### Glossary title:TOTFinder Technical Glossary
### Author:Ernesto Veras
### Description:A Glossary of English Technical Terms including a number of fields.
### Source language:English
### Source alphabet:Default
### Target language:English
### Target alphabet:Default
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2N2
Lunar elliptic semi diurnal second-order constituent.



ABATEMENT
Involves either removal of the painted surface, covering the painted surface with an impermeable surface, or covering surface with heavy-duty coating (encapsulant).



ABAXIAL
Surface of any structure which is remote or turned away
from the axis, such as the lower surface of a leaf.



Absence of Privity
Introduced into law during the Roman Empire to limit claims against an individual by unrelated or remote parties. In effect, the law stated that a contractual relationship (called privity) must exist between two parties in order to impose liability on one of the parties. In the absence of privity, liability cannot be imposed.



ABSOLUTE MEAN SEA LEVEL CHANGE
An eustatic change in mean sea level relative to the geographic center of the Earth.



ABSORPTION
1. The taking in of water and dissolved minerals and nutrients across cell membranes. Contrast with ingestion; 2. the process by which incident light is removed from the atmosphere and retained by a particle; 3. The process by which chemicals in gaseous, liquid or solid phases are incorporated into and included within another gas, liquid, or solid chemical.



ABSORPTION COEFFICIENT
a number that is proportional to the "amount" of light removed from a sight path by absorption per unit distance.



ABSORPTION CROSS SECTION
the amount of light absorbed by a particle divided by its physical cross section.



ABSORPTION SPECTRUM




ABYSSAL PLAIN
The ocean floor offshore from the continental margin, usually very flat with a slight slope.



ACAULESCENT
Having no stem or seemingly without a stem.



ACCELERATOR
Any device used to impart kinetic energy to electrically charged particles including, but not limited to, electrons, protons, deuterons and helium ions.



ACCEPTABLE DAILY INTAKE
[See REFERENCE DOSE]



ACCEPTED VALUES
Tidal datums and Greenwich high and low water intervals obtained through primary determination or simultaneous observational comparisons made with a primary control tide station in order to derive the equivalent of a 19-year value.



ACCESSORY FLOWER PARTS
Sepal and petal organs found on flowers.



ACCESSORY OCULOMOTOR NUCLEUS
Receives input from the pretectal area, innervates the ciliary ganglion. Mediates pupillary light reflexes.



ACCESSORY OPTIC SYSTEM
Region of the vertebrate midbrain to which some optic nerve fibers project. Cells respond to large slowly moving textured patterns and are selective for both direction and speed of motion suggesting they are involved in the computation of global motion. Possibly used for the detection of retinal slip and used in image stabilization. Consists of two sets of retina ganglion cell fibers and three target nuclei in the anterior portion of the midbrain, the dorsal, medial and lateral nuclei.



ACCIDENTAL VIEW
A special view of an object in which small perturbations in lighting or viewing direction drastically change its appearance. For example, imagine looking at a pencil straight on from the tip. (As opposed to Generic View).



ACCOMMODATION
Adjustment of the optics of an eye to keep an object in focus on the retina as its distance from the eye varies. Process of adjusting the focal length of a lens.



ACHENE
Any small, dry fruit with one seed whose outer covering (pericarp) does not burst when ripe.



ACHROMATOPSIA
A loss of color vision unaccompanied by attendant loss of other perceptual functions.



ACICULAR
Slender and pointed; needle-like and with a sharp point.



ACID DEPOSITION
air pollution produced when acid chemicals are incorporated into rain, snow, fog, or mist.



ACIDIFICATION
the decrease of acid neutralizing capacity in water or base saturation in soil caused by natural or anthropogenic
processes.



ACOUSTIC DOPPLER CURRENT PROFILER
A current measuring instrument employing the transmission of high frequency acoustic signals in the water.



ACRE-FOOT
The volume of water (325,851 gallons of water) required to cover one acre of land with 12 inches of water.



ACROPETAL
Developing upward from the base toward the apex.



ACRYLIC
A synthetic resin used in high-performance water-based coatings. A coating in which the binder contains acrylic resins.



ACTINOMORPHIC
Descriptive of a flower or set of flower parts which can be cut through the center into equal and similar parts along two or more planes; having radial symmetry.



ACTION SPECTRA
A photoreceptor's relative spectral sensitivity.



ACUITY
The highest spatial frequency rsolvable with a grating of unity contrast (i.e. the maximum possibly contrast).



ACULEUS
A prickle growing from bark. pl. aculei.



ACUMEN
The point of an acuminate leaf.



ACUMINATE
Drawn out into a long point; tapering point.



ACUTE
Sharp at the end; ending in a sharp point.



ACUTELY HAZARDOUS WASTES
Wastes that EPA has determined to be so dangerous in small amounts that they are regulated the same way as are large amounts of other hazardous wastes.



ADAPTATION
A change in the sensitivity to light of a photoreceptor or the visual system as a whole to match the average light intensity present.



ADAXIAL
Pertaining to the side of an organ toward the axis, such as the upper surface of a leaf.



ADCP
[See ACOUSTIC DOPPLER CURRENT PROFILER]



ADDUCT
To draw towards the main axis of the body or a limb.



ADENOSINE TRIPHOSPHATE
A relatively stable, high energy molecule used to fuel chemical reactions within cells.



ADHESION
The ability of dry paint to attach to and remain fixed on the surface without blistering, flaking, cracking or being removed by tape.



Adjusted Low Bid
A form of best value selection in which qualitative aspects are scored on a 0 to 100 scale expressed as a decimal; bid price is then divided by a qualitative score to yield an "adjusted bid" or "cost per quality point". Award is made to offeror with the lowest "adjusted bid".



ADNATE
Fusion of unlike structures or parts.



ADR
[See ADR GAUGE]



ADR GAUGE
[Analog to Digital Recording tide gauge] A float or pressure actuated tide gauge that records the heights at regular time intervals in digital format.



ADSORPTION
The adherence of gas molecules, ions or solutions to the surface of solids.



ADULT
The mature stage of an organism, usually recognized by the organism's attaining the ability to reproduce.



ADVECTION
The process by which chemicals and heat are transported along with the bulk motion of flowing gas or liquid.



ADVENTITIOUS
Plant structures or tissue occurring in an abnormal positon.



ADVENTITIOUS ROOTS
A root that grows from somewhere other than the primary root, for example, roots that arise from stems or leaves.



ADVENTIVE
A plant that is not native to the environment.



AEOLIAN
Soil transported from one area to another by wind.



AERENCHYMA
Parenchyma tissue with large and abundant intercellular air spaces; air-storing tissue; resembles the tissue of cork.



AEROBIC
a. Aerobic organisms require oxygen for their life processes; b. Pertaining to the presence of free oxygen.



AEROSOL
1. A mixture of microscopic solid or liquid particles in a gaseous medium. Smoke, haze, and fog are aerosol examples; 2. A product that uses compressed gas to spray the coating from its container.



AFFERENT
Heading towards. A system's afferent signals are those entering the system from elsewhere. (As opposed to Efferent)



AFFORDANCE
A possibility for action afforded to a perceiver by an object. The affordances of an object depend upon the perceiver as well as upon the characteristics of the object. For example, a stream affords such actions as jumping and paddling to a person, but to an frog it affords swimming.



AFTERIMAGE
A long lasting change in perceived brightness that occurs after prolonged viewing of a given luminance that remains after the luminance has been changed. Presumably due to adaptation in the exposed region.



AGE OF DIURNAL INEQUALITY
The time interval between the maximum semimonthly north or south declination of the Moon and the maximum effect of the declination upon range of tide or speed of the current.



AGE OF MOON
The time elapsed since the preceding new Moon



AGE OF PARALLAX INEQUALITY
The time interval between perigee of the Moon and the maximum effect of parallax upon range of tide or speed of the tidal current.



AGE OF PHASE INEQUALITY
The time interval between new or full Moon and the maximum effect of these phases upon range of tide or speed of the tidal current.



AGE OF TIDE
[See AGE OF PHASE INEQUALITY]



AGGER
[See DOUBLE TIDE]



AGGREGATE
Crowded into a cluster; a number of separate fruits from a single flower aggregated together; an aggregate flower is formed by a cluster of carples.



AGGREGATE FIELD
The area within which the receptive fields of cells in a single hypercolumn of the visual cortex fall.



AGULHAS CURRENT
An Indian Ocean current setting southwestward along the southeast coast of Africa.



AIR ACOUSTIC RANGING SENSOR
A pulsed, acoustic ranging device using the air column in a tube as the acoustic sound path.



AIR CONTAMINANT
Particulate matter, dust, fumes, gas, mist, smoke, vapor or any combination thereof.
[Air contaminant sources] --> Any and all sources of emission of air contaminants, whether privately or publicly owned or operated.



AIR CURE
A method by which liquid coatings cure to a dry film.



AIR CURTAIN DESTRUCTOR
A unit consisting of a combustion chamber pit and air blower designed to establish a curtain of high velocity air above the fire burning in the pit so that the products of combustion must be forced up through the curtain before they reach the outside air.



AIR DRY
[See AIR CURE]



AIR PARCEL
a volume of air that tends to be transported as a single entity.



AIR POLLUTANT
an unwanted chemical or other material found in the air.



AIR TEMPERATURE SENSORS
Sensors located in the protective well for the purpose of verifying uniformity of temperature for measurements taken by the air acoustic ranging sensor.



ALASKA CURRENT
A North Pacific Ocean current setting counterclockwise along the coasts of Canada and Alaska in the Gulf of Alaska.



ALASKAN STREAM
A North Pacific Ocean current setting westward along the south side of the Aleutian Islands. It is an extension of the Alaska Current.



ALGINATE
component of the cell walls of many rhodophytes and kelps. Alginates have an affinity for water, and so help to slow dessication when the algae are exposed to the air; they are commercially important in the production of paper, toothpaste, beer, and frozen foods.



ALIASING
Results when density of sampling is less than density of signal. One can only measure the portion of the input falling over the sampled positions. Sampled values for two different signals can be the same when the in-between values are different. (See also NYQUIST LIMIT).



ALKALINE
Term pertaining to a highly basic, as opposed to acidic, subtance.



ALKYD
Synthetic resin modified with oil. Coating that contains alkyd resins in the binder.



ALLELE
One of a pair or more of alternative hereditary characters; a gene which can occupy the same locus as another gene in a particular chromosome.



ALLELES
Alternative forms of a genetic locus.



ALLELOCHEMICALS
compounds that have an allelopathic effect.



ALLELOPATHY
The influence or effect of one living plant upon another; refers to biochemical interaction between all types of plants and its effect depends on a chemical compound being added to the environment.



ALLELOTROPIA
A depth percept can cause a shift in perceived form, namely change in the perceived distance between patterns in a configuration. For example that a pattern AB C is viewed in one eye and the pattern A BC is viewed through the other, the letter B is seen in depth at a position halfway between A and C.



ALLOCHTHONOUS
Refers to something formed elswhere than its present location. Antonym of autochthonous.



ALLUVIAL
Referring to alluvium, the type of soil found in flood plains.



ALTERNATE
Said of leaves occurring one at a node; said also of members of adjacent whorls in the flower when any member of one whorl is in front of or behind the junction of two adjacent members of the succeeding whorl.



ALTERNATION OF GENERATIONS
1. The occurrence in one life history of two or more different forms differently produced, usually an alternation of a sexual with an asexual form; 2. Life cycle in which haploid and diploid generations alternate with each other [see also HAPLOID-DIPLOID LIFE CYCLE].



ALVEOLA
A pit on the surface of an organ.



ALVEOLATE
Deeply pitted so as to resemble a honeycomb, as are the surfaces of some seeds or achenes.



AMACRINE CELL
A type of neuron seen in the retina.



AMBIENT VISION
The role of vision involved in orienting an animal in space and guiding its larger movements. Sensitive to motion and dependent on peripheral vision. (As opposed to Focal Vision).



AMBLYOPIA
An abnormal development of spatial vision associated with anisometropia or strabismus in early life. Visual acuity is reduced in the defocused or deviated eye as a result.



AMIDE
A functional group which can act as an epoxy resin curing agent.



AMINO ACID
unit molecule from which proteins are constructed by polymerization.



AMODAL
Perceptually present, but not having a real phenomenological presence. (As opposed to Modal).



AMODAL COMPLETION
The creation of a subjective contour that is without local sensory attributes e.g. contrast difference. It is neither a cognitive inference nor a projection but a direct perception. Seen most often in displays that have partially occluded objects. (See also MODAL COMPLETION).



AMOEBOID
Having no definite shape to the cell, able to change shape.



AMPHIDROMIC POINT
A point of no amplitude of the observed or a constituent tide.



AMPHIDROMIC REGION
An area surrounding an amphidromic point from which the radiating cotidal lines progress through all hours of the tidal cycle.



AMPHIESMA
The outer covering of a dinoflagellate, consisting of several membrane layers.



AMPLITUDE
One-half the range of a constituent tide.



ANAEROBIC
a. Anaerobic organisms do not require oxygen for their life processes, in fact oxygen is toxic to many of them. Most anaerobic organisms are bacteria or archaeans; b. Pertaining to the absence of free oxygen.



ANAEROBIOSIS
Life in the absence of air or free oxygen; anaerobic respiration, respiration occurring in the absence of oxygen.



ANAGLYPH
Device for creating 3-D images using red and blue filters for the two eyes.



ANALOG
[As used in the National Ocean Service] A continuous measurement or a continuous graphic display of data.



ANASTOMOSIS
a. A natural communication between two vessels; may be direct or by means of connecting channels; b. The surgical or pathological connections of two tubular structures; c. Connecting by cross-veins and forming a network.



ANATOMY
The branch of morphology that deals with the structure of plants, esp. the internal structure as revealed by the microscope.



ANCHORING
In any scene, the object which is the lightest is perceived as being white, or is 'anchored' to white.



ANDESITE
Igneous volcanic rock, less mafic than basalt, but more mafic than dacite; rough volcanic equivalent of diorite.



ANDROECIUM
Male reproductive organs of a plant; a collective term applied to all structures of the stamen whorl or whorls.



ANDROGYNAL
Bearing staminate and pistillate flowers on the same parent stem.



ANDROGYNOUS
Staminate flowers above the pistillate flowers in the same inflorescence.



ANDROPHORE
A support or column, formed by fusion of filaments, on which the stamens are borne.



ANEMOPHILY
Pollination by wind.



ANGIOSPERMAE
A major division of the plant kingdom, commonly called flowering plants as their reproductive organs are in flowers, having seeds which develop in a closed ovary made of carpels, a very reduced gametophyte, and endosperm develop from a triple fusion nucleus.pl. Angiosperms.



ANGLE OF INCIDENCE
Angle between an incident ray of light and the perpendicular to a surface.



ANGLE OF REFLECTION
Angle between a reflected ray of light and the perpendicular reflecting surface. (See ANGLE OF INCIDENCE).



ANGLE OF REFRACTION
Angle between a refracted ray of light and the perpendicular to the refracting surface. (See ANGLE OF INCIDENCE).



angular velocity of the Earth's rotation
Time rate of change of angular displacement relative to the fixed stars. It is equal to 0.729,211 x 10^-4 radian/second.



ANION
A negatively charged chemical.



ANION EXCHANGE
The chemical process where negative ions of one chemical are preferentially replaced by negative ions of another chemical.



ANISOMETROPIA
A disorder involving unequal refractive errors in the two eyes.



ANISOTROPIC
Any process or filter which is directionally selective or biased. (As opposed to Isotropic).




ANNUAL
A plant which completes its life history within a year.



ANNUAL INEQUALITY
Seasonal variation in water level or current, more or less periodic, due chiefly to meteorological causes.



ANOMALISTIC
Pertaining to the periodic return of the Moon to its perigee or the Earth to its perihelion.



ANOMALY
As applied to astronomy, the anomaly is the angle made at any time by the radius vector of a planet or moon with its line of apsides, the angle being reckoned from perihelion or perigee in the direction of the body's motion.



ANOXIA
Lack of oxygen or not enough oxygen.



ANTARCTIC CIRCUMPOLAR CURRENT
[See WEST WIND DRIFT]



ANTERIOR
Before or in front of.



ANTHER
The top of the stamen, usually elevated by means of a filament, which contains the pollen.



ANTHESIS
Stage or period during which the flower bud is fully open; flowering.



ANTHOPHYTE
A flowering plant, or any of its closest relatives, such as the Bennettitales, Gnetales, or Pentoxylales.



ANTHROPOGENIC
Arising from human activities, as opposed to natural origin.



ANTI-FOULING PAINT
Paints formulated especially for boat decks and hulls, docks and other below-water-line surfaces and structures to prevent the growth of barnacles and other organisms on ships' bottoms.



ANTICLINE
A fold of rock layers that is convex upwards. Antonym of syncline.



ANTICYCLONIC RING
A meander breaking off from the main current and spinning in a clockwise direction in the northern hemisphere (counter-clockwise in southern).



ANTILLES CURRENT
A North Atlantic Ocean current setting northwestward along the northeast coasts of the Bahama Islands.



ANTRORSE
Forward or upward.



APERTURE
Small opening, for example the opening in the test of a foram.



APERTURE PROBLEM
Any motion detecting device with a field of view which is small relative to an edge moving through it can only detect the component of velocity at right angles to the edge, while the component parallel to the edge is invisible.



APETALOUS
Having flowers without petals; having no corolla.



APHELION
The point in the orbit of the Earth (or other planet, etc.) farthest from the Sun.



APICAL
At the tip or summit.



APICAL MERISTEM
Group of cells at the growing tip of a branch or root. It divides cells to create new tissues.



APICULATE
Abruptly by a small, distinct point, an apiculus or apicule.



APOCARPOUS
Having separate carpels.



APOGEAN TIDES
Tides of decreased range or currents of decreased speed occurring monthly as the result of the Moon being in apogee.



APOGEE
1. The point in the orbit of the Moon or man-made satellite farthest from the Earth; 2. The point in the orbit of a satellite farthest from its companion body.



APOMIXIS
In general, reproducing without sexual reproduction; often used to denote seed production without a sexual process having been involved.



APPARENT MOTION
A observer presented with a display in which two items (lines, dots) in different locations are alternately exposed at certain interstimulus intervals will report seeing the item move from the first position to the second position. Illusion depends on the spatial separation, luminance and duration of the items. (See also TRANSFORMATIONAL APPARENT MOTION)




APPARENT SECULAR TREND
The nonperiodic tendency of sea level to rise, fall, or remain stationary with time.



APPARENT TIME
Time based upon the true position of the Sun as distinguished from mean time, which is measured by a fictitious Sun moving at a uniform rate.



APPRESSED
Lying flat or close against something. Often used for hairs.



APSIDES
The points in the orbit of a planet or moon which are the nearest and farthest from the center of attraction.



AQUATIC PLANTS
Plants that must grow in water whether rooted in the mud or floating without anchorage; plants that must complete part or all of their life cycle in or near the water.



AQUATIC VASCULAR PLANTS
Aquatic plants containing the conductive vascular tissue, phloem and xylem.



AQUICLUDE
A saturated formation that will not yield water in usable quantities.



AQUIFER
The saturated underground formation that will yield usable amounts of water to a well or spring.



ARACHNOID
Like a cobweb; covered with or consisting of soft fibers or hairs so entangled as to give a cobwebby appearance.



ARCHEGONIUM
The organ on a gametophyte plant which produces the egg cell, and nurtures the young sporophyte.



ARCUATE
Bend like a bow, from arcus, a bow) bent or curved in the form of a bow.



AREA CENTRALIS
Area in a vertebrate retina rich in cones, with little pooling of receptor outputs. In the human eye, the area centralis corresponds to the fovea, but this in not so in all species.



AREA CONTRAST
A contrast effect which is not limited to the borders of an enclosed region. The change of brightness produced by contrast at the edges of the region spreads uniformly over the entire enclosed region. (As opposed to Border Contrast).



ARGUMENT
[See EQUILIBRIUM ARGUMENT]



ARIL
An additional covering that forms on some seeds after fertilization, and developing from the stalk of the ovule.



ARISTATE
Awned; having an awn.



AROM
Aggressive range of motion



ARTESIAN AQUIFER
[See CONFINED AQUIFER]



ARTICULATE
Having joints; jointed; provided with places where separation may take place.



ARTIFICIAL RECHARGE
The unnatural addition of surface waters to groundwater.



Artistic impression
[Synchronized Swimming] An effect, image or feeling retained as a result of a swimmer's routine, covers the three areas of choreography, interpretation of music and manner of presentation.



Artistic impression score
[Synchronized Swimming] The score given by each judge of panel two for: choreography, music interpretation and manner of presentation.



ASCENDING
Rising or curving upward.



ASEPALOUS
Without sepals.



ASEXUAL REPRODUCTION
A type of reproduction involving only one parent that usually produces genetically identical offspring.



ASSIMILATION
A neutral pattern of intermediate luminance appears brighter if a superimposed pattern is made of high luminance lines, yet darker if the pattern consists of low luminance lines. This effect is in the opposite direction as is seen in simultaneous contrast.



ASTRES FICTIFS
Fictitious celestial bodies which are assumed to move in the celestial equator at uniform rates corresponding to the speeds of the several harmonic constituents of the tide producing force.



ASTRONOMICAL DAY
[See ASTRONOMICAL TIME]



ASTRONOMICAL TIDE
[See TIDE]



ASTRONOMICAL TIME
Time formerly used in astronomical calculations in which the day began at noon rather than midnight.



ATP
[See ADENOSINE TRIPHOSPHATE]



ATTENUATE
Gradually narrowed to a long point at apex or base.



AUGMENTING FACTOR
A factor used in connection with the harmonic analysis of tides or tidal currents to allow for the fact that the tabulated hourly heights or speeds used in the summation for any constituent, other than S, do not in general occur on the exact constituent hours to which they are assigned, but may differ from the same by as much as a half hour.



AURICLE
Any ear-like lobed appendages.



AUTO-STEREOGRAM
Unlike classical Random Dot Stereograms (RDS Ref) which require two separate images presented dichoptically, an autostereogram consists of just one images viewed by two eyes simultaneously. A depth percept is attained from this image.



AUTOCHTHONOUS
Refers to something formed in its present location. Antonym of allochthonous.



AUTOGAMOUS
Relating to, or reproducing by autogamy.



AUTOGAMY
Self-fertilization, pollination of a flower by its own pollen.



AUTOMATIC GAIN CONTROL
A fast gain control that aims to a constant output by changing gain in proportion to signal strength



AUTOMATIC TIDE GAUGE
An instrument that automatically registers the rise and fall of the tide.



AUTOTROPH
Any organism that is able to manufacture its own food. Most plants are autotrophs, as are many protists and bacteria. Contrast with consumer. Autotrophs may be photoautotrophic, using light energy to manufacture food, or chemoautotrophic, using chemical energy.



AUXINS
Growth promoting hormones that cause cell elongation, and are responsible for many developmental responses including phototropism.



AVULSION
A tearing away forcibly of a part or structure.



AWN
A stiff, bristlelike appendage, usually at the end of a structure.



AXIL
The angle found between any two organs or structures.



AXILLA
The armpit.



AXILLARY
In an axil, growing in an axil, as buds.



AZIMUTH
Azimuth of a body is the arc of the horizon intercepted between the north or south point and the foot of the vertical circle passing through the body.



Backside Bus
A dedicated bus that connects a microprocessor to a Level 2 (L2) cache that is used to eliminate performance bottlenecks. No other system device shares the backside bus.



BACTERIOPHAGE
Virus which infects and destroys a bacterial host. Some phages, however, will incorporate their DNA into that of their host, and remain dormant for an extended period. For this reason, they have become essential tools of genetic engineers.



Ballet leg
[Synchronized Swimming] A position where one leg is extended perpendicular to the water surface, with the body in a back layout position.



Ballet leg double
[Synchronized Swimming] A position where the legs are together and extended perpendicular to the water surface, with the face at the surface.



BANDWIDTH
The ratio of the spatial frequencies at which half the maximum contrast sensitivity is obtained.




BARBELLATE
Provided, usually laterally, with fine, short points or barbs.



BARBER POLE ILLUSION
The direction of motion of a diagonal grating pattern drifting behind a rectangular aperture depends upon the elongation of the aperture. The prevailing explanation is that the perceived direction of motion results from the integration of motion signals from grting terminators at the edges of the aperture. As a vertically elongated aperture has larger number of terminators with vertical trajectories, vertical motion prevails.



BARK
The outermost covering of trees and some plants. This is composed of the cuticle or epidermis, the outer bark or cortex, and the inner bark or fiber.



BAROCLINIC
When isobaric surfaces of a fluid are not parallel with density surfaces.



BAROTROPIC
When isobaric surfaces of a fluid are parallel with density surfaces.



BASALT
Highly mafic igneous volcanic rock, typically fine-grained and dark in color; rough volcanic equivalent of gabbro.



BASEFLOW
That part of streamflow derived from groundwater flowing into a stream.



BAY
A part of a sea or lake indenting the shore line.



BAYOU
A marshy inlet or outlet of a lake, river, etc.; also a backwater.



BEACH NOURISHMENT
Artificial beach norishment is a desirable, if expensive, method of beach protection and is nearly always preferable to structural methods when affordable. Unfortunately, engineers used to consider sand stored in ecologically sensitive bays, lagoons, estuaries, and nearshore areas as an unlimited source of sand for beach nourishment.



BEDROCK
General term referring to the rock underlying other unconsolidated material, i.e. soil.



BENCH MARK
A fixed physical object or mark used as reference for a vertical datum.



BENGUELA CURRENT
A South Atlantic Ocean current setting northward along the southwest coast of Africa.



BENTHIC
Organisms that live on the bottom of the ocean are called benthic organisms. They are not free-floating like pelagic organisms are.



BENUSSI RING ILLUSION
(See KOFFKA-BENUSSI RING ILLUSION)




BERRY
a. Any fleshy simple fruit with one or more seeds and a skin, as a tomato, cranberry, banana, grape, etc.; b. several-sided indehiscent fruit with a fleshy pericarp and without a stony layer surrounding the seeds.



Best Value
A selection process in which proposals contain both price and qualitative components and the award is based upon an evaluation of a combination of price and qualitative considerations.



BIENNIAL
A plant requiring two years in which to complete its life cycle, the first year growing only vegetatively, the second flowering, fruiting, then dying.



BIFID
Forked; divided by a cleft.



BILABIATE
Having two lips, as a bilabiate corolla of a flower.



BILATERAL
Having two sides.



BILATERALLY SYMMETRICAL
When divisible into equal halves in one plane only; zygomorphic.



BILOCULAR
Divided into two cells or compartments.



BINDER
Solid ingredients in a coating that hold the pigment particles in suspension and attach them to the substrate.



BINDING PROBLEM
If color, form, and motion are processed in separate areas of the brain, how/where is this information reassembled to create a single unified percept? (e.g. a purple box moving to the left).



BINOCULAR DISPARITY
The difference in position of two retinal images of an object that do not fall on exactly corresponding retinal positions.



BINOCULAR FIELD
A receptive field which responds to a cells optimal stimulus if it is presented to either eye




BINOCULAR OVERLAP
The segment of the optic array sampled by both eyes.



BINOCULAR RIVALRY
Occurs when the two eyes are presented with different stimuli. Instead of seeing a summation of the two images, our perception switches from one image to the other.




BINOCULAR VISION
Vision performed with two eyes/sensors whose outputs are often used to extract relative stereoscopic depth.



BINOCULAR ZONE
The central region of the visual field from which light enter both eyes. (See also MONOCULAR ZONE).



BINOPTIC STIMULATION
When the same image is presented to each eye. (See also Dichoptic Stimulation and Monoptic Stimulation).



BIOCHEMISTRY
the study of those molecules used and manufactured by living things.



BIOGENIC
Describing changes in the environment resulting from the activities of living organisms.



BIOLOGICAL AMPLIFICATION
The increase in concentration of a chemical in organisms that reside in environments contaminated with low concentrations of various organic compounds.



BIOLUMINESCENCE
a. The emission of light by organisms; b. the production of light by a chemical reaction within an organism. The process occurs in many bacteria and protists, as well as certain animals and fungi.



BIOMASS
Weight of all living material in a unit area at an instantaneous time. May be expressed as g/m2, mt/ha, or other similar expressions.



BIOSTRATINOMY
The study of what happens between the death of an organism and burial. Part of taphonomy.



BIPOLAR CELL
Key interneurons in the retina. Antagonistic center-surround receptive field organization. Makes excitatory connections to ganglion cells.



BIPOLE FIELD
A set of long range oriented cells which are excited by cells of their orientation and inhibited by perpendicular orientations.



BISEXUAL
a. Having both female and male reproductive organs present and functional in the same flower; hermaphrodite; b. Amphisporangiate; said of a plant having all bisexual flowers.



BISPORANGIATE
Flower or cone that produces both megaspores and microspores.



BISTRATED GANGLION CELL
Carry signal of the short wavelength cones. Dendritic trees stratified into two tiers near the inner and outer borders of the inner plexiform layer. Send output to parvocellular layer of LGN.



BLADE
1. The leaf of a plant, especially grass; the flat or expanded portion of a leaf; lamina; 2. Any broad and flattened region of a plant or alga, which allows for increased photosynthetic surface area.



BLEACHING
Photoreceptors, most notably rods, can be driven to saturation by bright visual stimuli and become insensitive to light changes in this region, then they are said to be 'bleached'.



BLIND SPOT
The location where optic nerve fibers leave the retina. This area has no photoreceptors and therefore no visual input. The cortex appears to fill-in this missing information so we are not conscious of the blind spot.



BLINDSIGHT
A phenomenon reported in individuals suffering from cortical blindness (i.e. damage to the primary visual cortex resulting in blindness). Individuals with blindsight report that they are unable to see, yet under forced choice conditions are able to indicate the presence and location of visually presented objects.



BLISTERING
Formation of dome-shaped projections in paints or varnish films resulting from local loss of adhesion and lifting of the film from the underlying surface.



BLOBS
Pillar like cortical sections, round or oval in sections cut parallel to the surface. Stain darkly when using cytochrome oxidase (Wong-Riley). Receive most input from parvocellular layers in the LGN via V1 layer 4C. Color selective cells, with no orientation preferences. Projects to thin stripes of V2.



BLOCK ARTIFACTS
Visual artifacts created when an image compressed with an algorithm using block coding is reconstructed. (See also BLOCK CODING)



BLOCK CODING
Any image processing technique which begins by subdividing the image into blocks. (See also BLOCK ARTIFACTS).



BLOOM
A blossom; the flower of a plant; an expanded bud; the opening of flowers in general, leaves, flowers, or fruits.



BLOSSOM
A flower or bloom, esp. of a fruit bearing plant. A state or time of flowering, literally, and figuratively.



BLUE BABY SYNDROME
[See METHEMOGLOBINEMIA]



BLUESCHIST
Metamorphic rock formed under great pressures, but not so great temperatures.



Bluetooth
A way to connect products to each other without using wires.



BODY
The thickness or viscosity of a fluid.



BOG
A quagmire covered with grass or other plants; wet, spongy ground; a small marsh; plant community on wet, very acid peat.



BOILED OIL
Linseed (sometimes soya) oil that was formerly heated for faster drying.



Boost
[Synchronized Swimming] A rapid, headfirst rise out of the water, aiming to raise as much of the body as possible above the surface.



BORDER CONTRAST
A localized contrast effect which is limited to the border immediately adjecent to the contrast discontinuity. (As opposed to Area Contrast).



BORE
[See TIDAL BORE]



BOTTOMLAND
Lowlands along streams and rivers, usually on alluvial floodplains that are periodically flooded.



BRACHIAL PLEXUS
Network of lower cervical and upper dorsal spinal nerves supplying the arm, forearm and hand.



BRACKISH
Mixed with salt; briny.



BRACKISH WATER
Water with a salt content between 1000 and 4000 parts per million.



BRACT
A modified leaf, growing at the base or on the stalk of a flower. It usually differs from other leaves in shape or color.



BRACTEOLATE
Furnished with bracteoles.



BRACTEOLE
A small bract; especially one on a floral axis.



BRANCH
A natural division of a plant stem.



BRANCHLET
A small usually terminal branch.



BRAZIL CURRENT
A South Atlantic Ocean current setting southwestward along the central coast of South America.



BREGMAN-KANIZSA DISPLAY
A display which suggests that the presence of visible occluders permits amodal completion which aid figure-ground segmentation and object recognition.



BREVITOXIN
neurotoxin produced by the dinoflagellate Ptychodiscus brevis.



BRIGHTNESS CONSTANCY
a. The perceived brightness of real objects in a natural environment is largely independent of changes in the overall illumination; b. Often mistakenly used for Lightness contrast. However there is evidence that luminescent objects can be perceived to be of the same luminance despite changes in ambient illumination or background.



BRISTLE
Stiff, strong but slender hair or trichome.



BRITISH EMPIRICISM
Rejects the notion that ideas were implanted in the mind at birth. Instead all complex ideas are built up for the sense organs. Ultimately all knowledge is achieved by associating simple sensations.




BROADBAND CHANNEL
(See MAGNOCELLULAR PATHWAY)



BROADBAND STIMULUS
A visual stimulus that can be considered to be the sum of a large number of sine-wave components.




BROW-SULZER EFFECT
An enhancement of brightness/darkness perception is found in the time domain. Stimuli of short duration evoke stronger sensations than stimuli of long uration.



BRYOPHYTE
Plants in which the gametophyte generation is the larger, persistent phase; they generally lack conducting tissues. Bryophytes include the Hepaticophyta (liverworts), Anthocerotophyta (hornworts), and Bryophyta (mosses).



BUBBLER TIDE GAUGE
[See GAS PURGED PRESSURE GAUGE]



BUD
A small swelling or projection on a plant, from which a shoot, cluster of leaves, or flowers develops; a rudimentary, undeveloped shoot, leaf, or flower; gemma.



BUE
Bilateral Upper Extremities.



BULB
A specialized underground bud that sends down roots and consists of a very short stem covered with leafy scales or layers which store water and nutrients, the whole enclosing next year's bud.



BUTADIENE
A gas which is chemically combined with styrene to create a resin used in latex binders, styrene-butadiene.



Cadence action
[Synchronized Swimming] A sequence of identical movements performed one by one by all team members, usually in rapid succession.



CADUCOUS
Said of a plant part, such as a sepal, petal, or leaf, that falls off quickly or early.



CAFE WALL ILLUSION
Although the lines composing the image are parallel, they do not appear to be.



CALCAREOUS
Refers to substances containing or composed of calcium carbonate.



CALCARINE SULCUS
Location of V1 in the human occipital lobe. The central visual field is represented in hte psoterior calcarine sulcus. The peripheral visual field is represented in the anterior portion of the calcarine sulus.




CALCIUM CARBONATE
a "salt" used by many marine invertebrates, such as corals and echinoderms, and by protists, such as coccolithophorids, to construct their exoskeletons.



CALIFORNIA CURRENT
A North Pacific Ocean current setting southeastward along the west coast of the United States and Baja California.



CALLIPPIC CYCLE
A period of four Metonic cycles equal to 76 Julian years, or 27,759 days.



CALLUS
A hard protuberance or callosity; new tissue covering a wound.



CALYX
The outer covering of a flower external to the corolla, which it encloses, and consisting of a whorl of leaves, or sepals, usually of a green color and less delicate in texture than the corolla.



CALYX TUBE
Tube formed by wholly or partially fused sepals. Not the floral tube of an epigynous or perigynous flower.



CAMBIUM
The layer of tissue between the bark and wood in woody plants, from which new wood and bark develops.



CAMPANULATE
Bell-shaped, usually applied to calyx and corolla.



CANARY CURRENT
A North Atlantic Ocean current setting southward off the west coast of Portugal and along the northwest coast of Africa.



CANCELLATE
Latticed, or resembling a latticed construction, usually said of a surface such as that of an achene or seed.



CANONICAL VIEWPOINT
A particular viewpoint of an object that people are more likely to imagine, quicker to name and more likely to classify as the best view of an object. Suggests that object pesentation may not be viewpoint independent.



CANOPY
Layer of vegetation elevated above the ground, usually of tree braches and epiphytes. In tropical forests, the canopy may be more than 100 feet above the ground.



CAPILLARY
a. Any of the minute blood vessels, averaging 0.008mm in diameter, carrying blood and forming the capillary system. Capillaries connect the smallest arteries (arterioles) with the smallest veins (venules); b. Pertinent to hair; hairlike; c. Resembling hair in the manner of growth; very slender, threadlike.



CAPILLARY FRINGE
A zone of partially saturated material just above the water table.



CAPITATE
Enlarged or swollen at tip, gathered into a mass at apex, as compound stigma; a knoblike stigma terminating a style.



CAPITULUM
An infloresence forming a head of sessile flowers or florets crowned together on a receptacle and usually surrounded by an involucre.



CAPSID
The protein "shell" of a free virus particle.



CAPSULE
A case, pod, or fruit, containing seeds, spores, or carpels; it usually bursts when ripe.



CARBOHYDRATES
class of biochemical compounds which includes sugars, starch, chitin, and steroids.



CARBON FILM
Thin layer of carbon remains of past life found in sedimentary rocks.



CARBONATE
Sediment, or rocks formed by sediment, derived from the precipitation of calcium, magnesium, or iron carbonates, (CaCO3, MgCO3, or FeCO3) either from inorganic or oganic sources. For example, limestone or dolomite.



CARINATE
Shaped like the keel of a ship; having a longitudinal prominence on the back, like a keel; applied to a calyx, corolla or leaf.



CARNIVORE
Literally, an organism that eats meat. Most carnivores are animals, but a few fungi, plants, and protists are as well.



CARPEL
A simple pistil, regarded as a modified leaf; also, any of the two or more carpels that unite to form a compound pistil; the unit of structure of the female portion of a flower.



CARPOPHORE
Generally the organ that supports the carpels; specifically, a very much elongated axis to which the carpels are attached.



CARYOPSIS
A small one-seeded, dry, indehiscent fruit, in which the seed adheres to the thin pericarp, so that the fruit and seed are incorporated into one body, as in wheat and other kinds of grain.



CASTANEA
A genus of trees typified by the common chestnut.



CASTANEOUS
Relating to or having the color of a chestnut.



CATALYST
Substance whose presence increases the rate of a chemical reaction, e.g., acid catalyst added to an epoxy resin system to accelerate drying time.



CATAPHYLL
1. Any rudimentary leaf, as a bud scale, preceding the true foliage leaves; 2. In cycads, a scale-like modified leaf which protects the developing true leaves.



CATAPHYLLARY LEAVES
Rudimentary or scale-like leaves which act as a covering of buds.



CATARACTS
Opacifications of the crystalline lens of the eye, causing a loss of transparency. The crystalline lens is the "focussing" mechanism of the human eye. The change in light transmission is due to accumulation of water and/or denaturation of the lens protein. A variety of factors cause cataracts, eg diabetes, eye trauma, age related changes.



CATION
A positively charged chemical. For example, calcium (Ca+2), and Magnesium (Mg+2).



CATION EXCHANGE
A process where positively charged ions of one chemical are preferentially replaced by positive ions of another chemical.



CATKIN
A scaly spike, the flowers of which are unisexual and petalless.



CAUDEX
The base of a perennial plant; the axis or stem of a woody plant, especially of a palm or tree fern.



CAULESCENT
having a well-developed stem above ground level.



CAULINE
Stem.



CELESTIAL SPHERE
An imaginary sphere of infinite radius concentric with the Earth, on which all celestial bodies except the Earth are imagined to be projected.



CELL
Fundamental structural unit of all life. The cell consists primarily of an outer plasma membrane, which separates it from the environment; the genetic material (DNA), which encodes heritable information for the maintainance of life; and the cytoplasm, a heterogeneous assemblage of ions, molecules, and fluid.



CELL CYCLE
Complete sequence of steps which must be performed by a cell in order to replicate itself, as seen from mitotic event to mitotic event. Most of the cycle consists of a growth period in which the cell takes on mass and replicates its DNA. Arrest of the cell cycle is an important feature in the reproduction of many organisms, including humans.



CELL MEMBRANE
The outer membrane of a cell, which separates it from the environment. Also called a plasma membrane or plasmalemma.



CELL WALL
1. Any tough layer which surrounds a cell and its cell membrane. In plants, this wall is composed of cellulose; 2. Rigid structure deposited outside the cell membrane.



CELLULOSE
a. carbohydrate polymer of the simple sugar glucose. It is found in the cell walls of plants and green algae, as well as dinoflagellates. Cellulose is the most abundant compound on earth that is manufactured by living things; A carbohydrate of unknown molecular structure but having the composition represented by the empirical formula (C6H10O5)x.b; b. The chief substance composing the cell walls or woody part of plants.



CENTER-SURROUND
A type of spatial receptive field structure in which the central region of the receptive field and the Surround portion influence cell activities in different ways e.g. ON-center, OFF-Surround




CENTIBAR
The unit of pressure equal to I ton per meter per second per second.



CENTRIFUGE
A device which spins or whirls test tubes at high speeds.



CENTRUM
central portion.



CESPITOSE
Growing in tufts or clumps; matted.



CESQG
[See CONDITIONALLY EXEMPT SMALL QUANTITY GENERATOR]



CHAFF
Dry scales or bracts, as those on the receptacle subtending the flowers in the heads of certain Compositae.



CHALKING
Formation of a powder on the surface of a paint film caused by disintegration of the binder during weathering.



CHANNELED
Having a deep longitudinal groove.



CHART DATUM
The datum to which soundings on a chart are referred. It is usually taken to correspond to a low-water elevation, and its depression below mean sea level is represented by the symbol Z .



CHARTACEOUS
Having the texture of thin but stiff paper.



CHARTER SCHOOL
Schools that are authorized by a government entity (such as a public university or a school district) and financed by the same per-pupil funds that traditional government schools receive.



CHARYBDIS
[See GALOFARO]



CHASMOGAMY
The opening of the perianth of a flower for the purpose of fertilization; contrast with cleistogamous.



CHERT
Hard, dense sedimentary rock, composed of interlocking quartz crystals and possibly amorphous silica (opal). The origin of the silica is normally biological, from diatoms, radiolaria or sponge spicules. Synonymous with flint.



CHITIN
carbohydrate polymer found in the cell walls of fungi, and in the exoskeletons of arthropods. It is the compound which makes cockroaches "crunchy".



CHLORINATED HYDROCARBON
Synthetic chemical substance containing chlorine, hydrogen, and carbon. The addition of chlorine to organic compounds causes these materials to break down slowly in the environment.



CHLORINITY
The number giving the chlorinity in grams per kilogram of a seawater sample is identical with the number giving the mass in grams of atomic weight silver just necessary to precipitate the halogens in 0.328,523,3 kilogram of the seawater sample.



CHLOROPHYLL
photosynthetic pigment. It includes a porphyrin ring, and often has a long hydrophobic tail.



CHLOROSIS
Abnormal condition characterized by absence of green pigments in plants.



CHORIPETALOUS
Polypetalous; having unconnected or separate petals.



CHROMA
A measurement of color. The degree of saturation of a hue.



CHROMATIC ADAPTATION TECHNIQUE
Used to identify receptor inputs. An adapting light is chosen such that it affects the response to one of the inputs to a cell far more than the other. The cells response is selectively desensitized so that the cell is largely driven by the other input. This way the response properties of the cell can now be studied in relative isolation.



CHROMOSOME
Linear piece of eukaryotic DNA, often bound by specialized proteins known as histones.



CHROMOSTEREOPSIS
The optics of the eye are such that short wavelengths are refracted slightly more than long wavelengths creating a positional disparity on the retina. When viewed by two eyes a stereoscopic disparity is obtained. This is termed Chromostereopsis or Chromatic Stereopsis



CILIARY GANGLION
Contains postganglionic neurons that innervate the smooth muscles of the pupillary sphincter, mediate pupillary reflexes. Receives input from the accessory oculomotor nucleus. (See FIGURE).



CILIATA
With marginal hairs that form a fringe.



CIRCUMSCISSILE
Opening splitting by a transverse fissure around the circumference, leaving an upper and lower half; said of certain seed pods or capsules.



CIVIL DAY
A mean solar day commencing at midnight.



CIVIL TIME
Time in which the day begins at midnight as distinguished from the former astronomical time in which the day began at noon.



CLASS I DISPOSAL FACILITY
A sanitary landfill that serves a municipal, institutional, and/or rural population and is used or is to be used for disposal of domestic wastes, commercial wastes, institutional wastes, municipal wastes, bulky wastes, landscaping and land clearing wastes, industrial wastes, construction demolition wastes, farming wastes, discarded automotive tires, and dead animals.



CLASS I INJECTION WELL
Injection wells that are regulated by federal and state permits. They include 1) wells used by generators of hazardous waste or owners/operators of hazardous waste management facilities to inject hazardous waste beneath the lowermost formation containing an underground source of drinking water (USDW) within a radius of one mile of the well bore; or 2) other industrial and municipal disposal wells that inject fluids beneath the lowermost formation containing a USDW within a radius of one mile of the well bore.



CLASS II DISPOSAL FACILITY
A landfill that receives waste generated by one or more industrial or manufacturing plants and that is used or is to be used for the disposal of solid waste generated by such plants, which may include industrial wastes, commercial wastes, institutional wastes, farming wastes, bulky wastes, landscaping and land clearing wastes, construction/demolition wastes, discarded automotive tires, and dead animals.



CLASS III DISPOSAL FACILITY
A landfill that is used or is to be used for the disposal of farming wastes, landscaping and land clearing wastes, and/or certain special wastes having similar characteristics.



CLASS IV DISPOSAL FACILITY
A landfill that is used or is to be used for the disposal of demolition/construction wastes, certain special wastes having similar characteristics and waste tires.



CLASS V DISPOSAL FACILITY
A land farming facility.



CLASS V INJECTION WELL
Injection wells or systems that are regulated either by permit or by rule and are not included in Classes I, II (oilfield brine), III (mineral extraction) or IV (hazardous waste). Class V wells include 1) air conditioning return flow wells used to return to the supply aquifer the water used for heating or cooling in a heat pump; 2) drainage wells used to drain surface fluid, primarily stormwater runoff, into a subsurface formation; 3) cooling water return flow wells used to inject water previously used for cooling; 4) recharge wells used to replenish the water in an aquifer; 5) sand backfill and other backfill wells used to inject a mixture of water and sand, mill tailings or other solids into mined-out portions of subsurface mines including radioactive waste; 6) radioactive waste disposal wells other than Class IV; and 7) other wells or systems as listed in DWS Rule 1220-4-6-.06.



CLASS VI DISPOSAL FACILITY
A surface impoundment used for disposal of solid waste.



CLASSIFICATION
[See TYPE OF TIDE]



CLAST
An individual grain or constituent of a rock.



CLAVATA
Club-shaped; having the form of a club; growing gradually thicker toward the top, as certain parts of a plant.



CLAW
The narrowed, stalklike base of some sepals or petals.



CLEAR COATING
A transparent protective and/or decorative film; generally the final coat of sealer applied to automotive finishes.



CLEFT
Divided halfway down to the midrib or further, or generally, any deep lobe or cut.



CLEISTOGAMY
The condition of having flowers which never open and self-pollination occurs, and the flowers are often small and inconspicuous.



CLONE
1. An identical copy of an organism; 2. A group of plants all of whose members are directly descended from a single individual.



CLOSED-LOOP CONTROL
A control system in which the output is continuously modified by feedback from the environment.




CLOSURE
Actions taken at the termination of a disposal operation which are necessary to finally close the disposal facility or disposal facility parcel.



COALESCENT AID
The small amount of solvent contained in latex coatings. Not a true solvent since it does not actually dissolve the latex resins.



COAST LINE
The low water datum line for purposes of the Submerged Lands Act (Public Law 31) [See SHORELINE].



COASTAL BOUNDARY
The mean high water line (MHWL) or mean higher high water line (MHHWL) when tidal lines are used as the coastal boundary.



COASTAL ZONE
The coastal waters (including the lands therein and thereunder) and the adjacent shorelands (including the waters therein and thereunder), strongly influenced by each and in proximity to the shorelines.



COASTLINE
[See SHORELINE]



COATING
A paint, varnish, lacquer or other finish used to create a protective and/or decorative layer.



COCURRENT LINE
A line on a map or chart passing through places having the same current hour.



COENOCYTIC
Condition in which an organism consists of filamentous cells with large central vacuoles, and whose nuclei are not partitioned into separate compartments. The result is a long tube containing many nuclei, with all the cytoplasm at the periphery.



COHERENT
Having parts united.



COHESION
A bonding together of a single substance to itself. Internal adhesion.



COLIFORM BACTERIA
Gram-negative, rod-shaped bacteria, including primary fecal coliform, found in the digestive tract, but other forms are found in soil and water.



COLLAGEN
Long proteins whose structure is wound into a triple helix. The resulting fibers have a high tensile strength. Collagen is a primary component of mammalian hair.



COLLAR
Region of junction between blade and leaf sheath of grasses.



COLLENCHYMA
Living, supportive tissue with chloroplasts generally just beneath the surface consisting or more or less elongated cells usually thickened unevenly in a manner somewhat variable in different groups of plants.



COLLUVIAL
Describing eroded material found at the bottom or on the lower slopes of a hill.



COLONIAL
1. Usually used to describe cloning by vegetative reproduction, the seemingly separate plants having arisen from rhizomes, stolons, or roots of a single or of neighboring "parent" plants; 2. Condition in which many unicellular organisms live together in a somewhat coordinated group. Unlike true multicellular organisms, the individual cells retain their spearate identities, and usually, their own membranes and cell walls.



COLONY
A stand, group, or population of neighboring plants of one species, the origin having been colonial, from seeds, or both.



COLOR CONSTANCY
Despite changes in wavelength (such as at sunset, or on cloudy days) objects are perceived to maintain their surface color.



COLOR OPPONENCY
When a cell is excited by one part of the visible spectrum and inhibited by another. First observed in ganglion cells in the retina.



COLOR OPPONENT CHANNEL
(See PARVOCELLULAR PATHWAY).



COLOR RETENTION
The ability of paint to keep its original color.



COLOR SPACE
A mathematical construct that allows us to visually denote different colors.




COLORANT
Concentrated color (dyes or pigments) that can be added to paints to make specific colors.



COLORFAST
Non-fading in prolonged exposure to light.



COLPATE
Having longitudinal germinal furrows in the exine.



COLUMELLA
A small column of tissue which runs up through the center of a spore capsule. It is present in hornworts, mosses, and some rhyniophytes.



COMA
A tuft of soft hairs, as at the apices or bases of seeds; a bunch of branches; a terminal cluster of bracts on a flowering stem, as in pineapples.



Combined spin
[Synchronized Swimming] A descending spin of at least 360 degrees followed, without a pause, by an equal ascending spin in the same direction.



COMMISSURE
A place of joining or meeting, as where one carpel joins another in the Umbelliferae.



COMMON FATE
(See GESTALT LAWS OF PERCEPTUAL ORGANIZATION).



COMMON SCHOOL
Refers to schools open to all people in a given community.



COMOSE
Having a tuft of hair.



COMPASS DIRECTION
Direction as indicated by compass without any allowances for compass error.



COMPASS ERROR
The angular difference between a compass direction and the corresponding true direction.



COMPETITION
Involves the removal or reduction of some factor from the environment by a plant or group of plants that is sharing the same habitat. Competition can be by an individual or groups of plants of the same or different species. Factors that may be reduced include water, minerals, food, and light.



COMPLEX CELLS
Cells in the primary visual cortex (V1) that responding either to an edge, a bar or a slit stimulus of a particular orientation falling anywhere in its receptive field. The exact location of the stimulus within the receptive field is not as critical. Have receptive fields longer than those of simple cells. The cell behaves non-linearly, responding to a drifting cosine grating with a uniform increase in activity with no sinusiodal modulcation (i.e. insensitive to phase). For a historical perspective see Simple Cells. (See also Hypercomplex Cells and Full-Wave Rectification).



COMPONENT
1. [See CONSTITUENT]; 2. That part of a tidal current velocity which, by resolution into orthogonal vectors, is found to act in a specified direction.



COMPOUND TIDE
A harmonic tidal (or tidal current) constituent with a speed equal to the sum or difference of the speeds of two or more elementary constituents.



COMPRESSION
The decrease in volume of a rock, rock unit or fossil caused by forces oriented in opposite directions.



Compulsory education
Laws requiring that children under a certain age be enrolled in school, usually a government school.



CONCENTRIC FIELD
A receptive field divided into an inner circular region and an outer ring-shaped region. Light falling in each of the two regions has opposite effects on the response of the cell.



CONCRETION
The act or process of making or becoming solid.



CONDITIONALLY EXEMPT SMALL QUANTITY GENERATOR
A generator who generates no more than 100 kilograms of hazardous waste in one calendar month.



CONE
Photoreceptor for day vision. Higher acuity and temporal resolution than rods. Mediates color vision. Highly concentrated in fovea. Graded responses (no action potential). There are three classes of cones, short, medium and long wavelength cones. (See also ROD).



CONE OF DEPRESSION
A depression in groundwater levels around a well in response to groundwater withdrawal or pumping water.



CONE OPSIN
Light absorbing molecule in cone cells



CONFINED AQUIFER
The saturated formation between low permeability layers that restrict movement of water vertically into or out of the saturated formation.



CONGLOMERATE
A coarse-grained sedimentary rock, with clasts larger than 2 mm.



CONNATE
Congenitally united.



CONNIVENT
Approximate but not organically united; converging; arching over so as to meet.



CONSTITUENT
One of the harmonic elements in a mathematical expression for the tide-producing force and in corresponding formulas for the tide or tidal current.



CONSTITUENT DAY
The time of the rotation of the Earth with respect to a fictitious celestial body representing one of the periodic elements in the tidal forces.



CONSTITUENT HOUR
One twenty-fourth part of a constituent day.



CONSTRUCTION
The fabrication, erection or installation of a stationary air emissions source or modification of such source.



CONSUMER
Any organism which must consume other organisms (living or dead) to satisfy its energy needs. Contrast with autotroph.



CONTAMINANT
Any unnatural biological, chemical, physical, or radiological substance or matter contained in water.



CONTINENTAL CRUST
The Earth's crust that includes both the continents and the continental shelves.



CONTINENTAL MARGIN
The ocean floor from the shore of continents to the abyssal plain.



CONTINENTAL RISE
Part of the continental margin; the ocean floor from the continental slope to the abyssal plain. The continental rise generally has a gentle slope and smooth topography.



CONTINENTAL SHELF
Part of the continental margin. the ocean floor from the coastal shore of continents to the continental slope, usually to a depth of about 200 meters. The continental shelf usually has a very slight slope, roughly 0.1 degrees.



CONTINENTAL SLOPE
Part of the continental margin; the ocean floor from the continental shelf to the continenetal rise or oceanic trench. usually to a depth of about 200 meters. The continental slope typically has a relatively steep grade, from 3 to 6 degrees.



CONTINGENCY PLAN
[hazardous wastes] A document setting out an organized, planned and coordinated course of action to be followed in case of fire, explosion or release of hazardous waste or hazardous waste constituents which could threaten public health or the environment.



Continuous spin
[Synchronized Swimming] A descending spin with a rapid rotation of at least 720 degrees, before the heels reach the surface.



CONTRACTILE VACUOLE
In many protists, a specialized vacuole with associated channels designed to collect excess water in the cell. Microtubules periodically contract to force this excess water out of the cell, regulating the cell's osmotic balance.



CONTRACTURE
a. Permanent contraction of a muscle due to spasm or paralysis; b. A condition of fixed high resistance to the passive stretch of a muscle, as may result from fibrosis of tissues surrounding a joint.



CONTRAST
The ratio between the maximum and minimum intensities in a light pattern.




CONTRAST-REVERSING GRATING
A space-time harmonic function.



CONTRAST SENSITIVITY FUNCTION
The reciprocal of the threshold contrast required to obtain a criterion response from a cell or a human subject as a function of spatial frequency. Falls off in sensitivity as the spatial frequency of the test pattern increases. (See also MODULATION TRANSFER FUNCTION)



CONTROL CURRENT STATION
A current station at which continuous velocity observations have been made over a minimum period of 29 days.



CONVENIENCE CENTER
Any area which is staffed and fenced that has waste receptacles on site that are open to the public when an attendant is present to receive household waste, municipal solid waste and recyclable materials.



CONVERGENCE
(See DEGREE OF CONVERGENCE).



CONVOLUTE
Said of parts rolled or twisted together when in an undeveloped stage, as in some corollas in the bud stage.



COPLANAR RATIO HYPHOTHESIS
A hypothesis by Gilchrist in which the visual system does not use retinal contrasts to determine relative lightnesses but uses depth information to determine which regions are at the same depth (coplanar) and uses their contrasts to deteremine the lightness perceived. This hypothesis has come under recent attack.



CORANGE LINE
A line passing through places of equal tidal range.



CORDATE
With a sinus and rounded lobes at the base, the overall outline usually ovate; often restricted to the base rather than to the outline of the entire organ; heart-shaped.



CORE
That portion of the interior of the Earth that lies beneath the mantle, and goes all of the way to the center. The Earth's core is very dense, rich in iron and the source of the magnetic field.



CORIACEOUS
Leathery; tough.



CORIOLIS FORCE
The apparent force, resulting from the earth's rotation, that deflects air or water movement. Winds seen from a moving frame of reference (the earth) are deflected to the right in the Northen Hemisphere.



CORM
An enlarged solid subterranean stem, often rounded in shape but of no distinct characteristic shape or size in some species, filled with nutrients, composed of two or more internodes and covered externally by a few thin membranous scales or cataphyllary leaves.



CORMOPHYTA
In older classifications, a division comprising all plants that have a stem and root.



CORMOPHYTE
A plant of the division Cormophyta.



COROLLA
The inner, usually colored or otherwise differentiated, whorl or whorls of the perianth; the petals of a flower as a whole.



CORRESPONDENCE PROBLEM
In Stereopsis - The challenge of matching elements in one eye with elements in another eye. Also known as the Matching Problem
In Motion - The challenge of matching moving elements in one frame with elements in a succeeding frame (especially true of random dot cinematograms).




CORRIDOR ILLUSION
The cylinders of equal size in a picture are perceive to be of different sizes when the lie in distinct positions within a rectangular grid whose spatial scale diminishes toward a fixation point on the horizon which create depth perspective cues. (See also PONZO ILLUSION).



CORROSION INHIBITIVE
A type of metal paint or primer that prevents rust by preventing moisture from reaching the metal.



CORROSIVE
A substance that dissolves metals and other materials or burns the skin.



CORTICAL MAGNIFICATION FACTOR
Defined as millimeters of cortex per degree of visual angle. Described by the following relationship: Where E is the retinal eccentricty in degress, E2, is the eccentricity at which magnification has changed by a factor of 2, and M2 is the foveal magnification (6-13 mm/deg). Integrating gives an expression for the distance, D, from the cortical mapping of the foveal center to a point at eccentricity E:




CORTICALTECTAL PATHWAY
Pathway from the cortex to the superior colliculi.



CORYMB
A racemose type of inflorescence in which the lower pedicels are successively elongated forming a more or less flat-topped inflorescence, the outer flowers opening before the inner.



COTIDAL HOUR
The average interval between the Moon's transit over the meridian of Greenwich and the time of the following high water at any place.



COTIDAL LINE
A line on a chart or map passing through places having the same cotidal hour.



COTYLEDON
The first leaf or leaves of a seed plant, found in the embryo of the seed which may form the first photosynthetic leaves or may remain below ground.



COUNTERCURRENT
A current usually setting in a direction opposite to that of a main current.



COUNTERCURRENT FLOW
The arrangement of material flow in a system designed to remove specific chemicals (such as sulfur oxides) from STACK GASES. The liquid containing the subtance that absorbs or reacts with the undesirable gas and the stack move throughout the system in opposite directions, and collection of the contaminant occurs when the streams collide.



CPD
Cycles per degree of visual angle. The human limit is about 30cpd in the fovea for an individual with 20/20 vision.




CRAIK-O'BRIEN CORNSWEET EFFECT
Two identically luminant rectangles except for a luminance cusp near the border appear to have different luminance levels.



Crane
[Synchronized Swimming] A position where the body is extended in a vertical position with one leg extended forward at a 90-degree angle.



CREEK
A natural stream of water normally smaller than and often tributary to a river.



CRENATE
Having a notched, indented, or scalloped edge, as certain leaves.



CREOSOTE
A liquid coating made from coal tar once used as a wood preservative.



CREST
The highest point in a propagating or standing wave.



CRITICAL FLICKER FREQUENCY
The frequency of flicker where the alternating levels of brightness are seen as a single level. The frequency is dependent on brightness levels and retinal location.



CROWN
That part of a stem at or just below the surface of the ground; an inner appendage of a petal or the throat of a corolla; an appendage or extrusion standing between the corolla and stamens, or on the corolla; an outgrowth of the staminal part or circle as in milkweeds.



CRUST
The outermost layer of the Earth, typically 5 to 75 km thick, representing less than 1 percent of the Earth's volume.



CULM
The stalk or stem for such plants as grasses and sedges, usually jointed and hollow.



CUNEATE
Narrowly triangular with the acute angle toward the base; wedge-shaped; tapering toward the point of attachment.



CURE
The process whereby a liquid coating becomes a hard film.



CURRENT
Generally, a horizontal movement of water. Currents may be classified as tidal and nontidal.



CURRENT CONSTANTS
Tidal current relations that remain practically constant for any particular locality.



CURRENT CURVE
A graphic representation of the flow of the current.



CURRENT DIAGRAM
A graphic table showing the speeds of the flood and ebb currents and the times of slacks and strengths over a considerable stretch of the channel of a tidal waterway, the times being referred to tide or tidal current phases at some reference station.



CURRENT DIFFERENCE
Difference between the time of slack water (or minimum current) or strength of current in any locality and the time of the corresponding phase of the tidal current at a reference station for which predictions are given in the Tidal Current Tables.



CURRENT DIRECTION
[See SET]



CURRENT ELLIPSE
A graphic representation of a rotary current in which the velocity of the current at different hours of the tidal cycle is represented by radius vectors and vectoral angles.



CURRENT HOUR
The mean interval between the transit of the Moon over the meridian of Greenwich and the time of strength of flood, modified by the times of slack water (or minimum current) and strength of ebb.



CURRENT LINE
A graduated line attached to a current pole used in measuring the velocity of the current.



CURRENT METER
An instrument for measuring the speed and direction or just the speed of a current.



CURRENT POLE
A pole used in observing the velocity of the current.



CURRENT STATION
The geographic location at which current observations are conducted.



CUSP
Rigid, sharp point, especially on a leaf.



CUSPIDATE
Tipped with a short, rigid point.



CUTICLE
A continuous layer of fatty substances covering over the outer surfaces of the epidermis of plants; it contains cutin and protects against water and gases.



CUTIN
A waxy substance which, together with cellulose, forms the outer layer of the skin of many plants.



CYANOSIS
Slightly bluish, grayish, slatelike or dark purple discoloration of the skin due to presence of abnormal amounts of reduced hemoglobin in the blood.



CYATHIUM
A type of inflorescence characteristic of some members of Euphorbiaceae; consisting of a cuplike involucre bearing unisexual flowers; staminate on its inner face, pistillate from the base.



CYCLONIC RING
A meander breaking off from the main current and spinning in a counter-clockwise direction in the northern hemisphere (clockwise in southern).



CYME
A cluster of flowers in which each main and secondary stem bears a single flower, the bud on the main stem blooming first; determinate inflorescence in which each growing point ends in a flower.



CYMOSE
Bearing a cyme or cymes.



CYSTOLITH
A mass of calcium carbonate concretion, occasionally silica, formed on ingrowths of modified epidermal cell walls in some plants, esp. of the Acanthaceae family.



CYTOCHROME OXIDASE
Histochemical method. Indicator of functional state of neurons as brain derives energy from oxidase metabolism. Used in the discovery of blobs in the visual cortex.




CYTOPLASM
All the contents of a cell, including the plasma membrane,but not including the nucleus.



CYTOSKELETON
Integrated system of molecules within eukaryotic cells which provides them with shape, internal spatial organization, motility, and may assist in communication with other cells and the environment. Red blood cells, for instance, would be spherical instead of flat if it were not for their cytoskeleton.



DACITE
Igneous volcanic rock, less mafic than andesite, typically fine-grained and light in color; rough volcanic equivalent of granodiorite.



DARK LIGHT
Rods spontaneously produce a signal that is indistinguishable from a photon elicited event even in complete darkness about once every 160 msec.



DATUM OF TABULATION
A permanent base elevation at a tide station to which all tide gauge measurements are referred.



DAVIDSON CURRENT
A North Pacific Ocean countercurrent setting northward between the California Current and the coasts of California, Oregon, and Washington during the winter months.



DAY
The period of rotation of the Earth.



DAY NEUTRAL PLANTS
Plants that flower regardless of day length.



DAYLIGHT SAVING TIME
A time used during the summer months, in some localities, in which clocks are advanced I hour from the usual standard time.



DEAD FLAT
No gloss or sheen.



DEBRIDEMENT
The removal of foreign materials and dead or damaged tissue, especially in a wound.



DECIBAR
The practical unit for pressure in the ocean, equal to 10 centibars.



DECIDUOUS
Falling after completion of the normal function.



DECIMETER
(dm), 3.973 inches, 10 cm, or 0.1 m.



Deckwork
[Synchronized Swimming] The mood-setting moves that swimmers perform on the deck once the music starts before they enter the water.



DECLINATION
Angular distance north or south of the celestial equator, taken as positive when north of the equator and negative when south.



DECLINATIONAL INEQUALITY
[See DIURNAL INEQUALITY]



DECLINATIONAL REDUCTION
A processing of observed high and low waters or flood and ebb tidal currents to obtain quantities depending upon changes in the declination of the Moon; such as tropic ranges or speeds, height or speed inequalities, and tropic intervals.



DECOMPOSITION
The breakdown of dead organic material by detrivores or saprophytes.



DECUMBENT
Trailing on the ground and rising at the tip, as some stems.



DECURRENT
Extending downward, applied usually to leaves in which the blade is apparently prolonged downward as two wings along the petiole or along the stem.



DEEP PERCOLATION
The movement of water below the maximum effective plant root zone.



DEGREE OF CONVERGENCE
The angle of inclination of the two eyes used in depth perception




Degree of difficulty
[Synchronized Swimming] A weighting applied to a particular figure for scoring purposes in a figure competition.



DEHISCE
To burst or split open, as the seed capsules of plants.



DEHISCENCE
Opening and shedding contents; said of stamens and fruits.



DELAYED MATCH-TO-SAMPLE
Subject is shown a stimulus and then after a delay is required to choose the same stimulus from a number of stimuli to obtain reward



DELTOID
Shaped like the Greek letter delta; triangular in outline.



DEMOLITION
The wrecking or taking out of any load-supporting structural member of a facility together with any related handling operations or the intentional burning of any facility.



DENTATE
Toothed, with large saw-like teeth on the margin pointing outward, not forward.



DENTICLE
A small tooth or toothlike projecting point.



DENTICULATE
Having small teeth; finely dentate.



DEOXYRIBONUCLEIC ACID
The nucleic acid which carries the genetic code of an organism. It is the primary component of chromosomes.



DEPOSITION
a. The washout or settling of material from the atmosphere to the ground or to surface waters; b. The absorption or adsorption in the respiratory tract of inhaled gases, vapors, or particles; c. Any accumulation of material, by mechanical settling from water or air, chemical precipitation, evaporation from solution, etc.



DEPTH CAPTURE
Objects in an image with no apparent depth information can be captured by surrounding surfaces which do contain depth information.



DEPTH CUES
(See MONOCULAR DEPTH CUES).



Descending spin
[Synchronized Swimming] A spin of 180 or 360 degrees that starts at the height of the vertical position and is completed as the heels reach the surface.



DETRITUS
Accumulated organic debris from dead organisms, often an important source of nutrients in a food web.



DETRIVORE
Any organism which obtains most of its nutrients from the detritus in an ecosystem.



DEVELOPMENT
The process by which a multicellular organism is produced from a single cell.



DEVIATION
[of compass] The deflection of the needle of a magnetic compass due to masses of magnetic metal within a ship on which the compass is located.



DIADELPHOUS
In two sets as applied to stamens when in two, usually unequal, sets.



DIAGENESIS
All of the changes that occur to a fossil (or more generally any sediment) after initial burial; includes changes that result from chemical, physical as well as biological processes. The study of diagenesis is part of taphonomy.



DIAPLOPIA
Double vision.




DIATOMITE
Diatomite, or diatomaceous earth, is a siliceous sedimaentary rock formed from the accumulations of diatoms or other nanoplankton.



DICHOPTIC STIMULATION
When different images are presented to each eye. (See also BINOPTIC STIMULATION and MONOPTIC STIMULATION).



DICHOTOMOUS
Having or consisting of a pair or pairs; paired.



DICHROMATIC COLOR VISION
Color vision based on two cone photoreceptor pigments in the retina. (See also TRICHROMATIC COLOR VISION and TETRACHROMATIC COLOR VISION).



Difficulty
[Synchronized Swimming] Complexity of movements, speed of movements, number if figures and hybrids.



DIFFRACTION
The scattering of rays of light by collision with particles of matter as they pass through a medium such as air or water, or pass by a edge or narrow aperture. Plays a role when the pupil is small.




DIFFUSION
Process where heat or chemicals are transported in response to differences in chemical concentration or temperature.



DIGITAL TIDE GAUGE
[See AUTOMATIC TIDE GAUGE]



DIGITATE
Having fingerlike divisions, as some leaves.



DIKARYOTIC
Having two different and distinct nuclei per cell; found in the fungi. A dikaryotic individual is called a dikaryon.



DILUENT
A liquid used in coatings to reduce the consistency and make a coating flow more easily. A diluent may also be called a "Reducer," "Thinner," "Reducing Agent" or "Reducing Solvent."



DIMORPHIC
Having two forms.



DINOSTERANES
[See DINOSTEROIDS]



DINOSTEROIDS
Chemicals found in dinoflagellates, which have been useful in documenting their existence early in the fossil record.



DIOECIOUS
Said of a kind of plant having unisexual flowers, the male and female flowers on different individual plants.



DIOPTER
Reciprocal meter. It is a measure of the power of a lens or optical system in bringing rays to a focus. The dioptric power of a thin lens is the reciprocal of the distance between the center of the lens and its focal point as measured in meters. (See also OPTICAL POWER).



DIORITE
Igneous plutonic rock, less mafic than gabbro, but more mafic than granite and granodiorite; rough plutonic equivalent of andesite.



DIP
The angle that a bedding plane or fault makes with the horizontal when measured perpendicular to the strike of the bedding plane or fault.



DIPLOID
Having twice the number of chromosomes normally occurring in a germ cell.



DIPLOID LIFE CYCLE
Occurs when the only multicellular stage in an organism's life cycle is diploid.



DIRECTION SELECTIVITY
A difference in the response of a cell to a pattern of light moving through it receptive field according to the direction of movement. Cells respond well when a stimulus moves in one direction and not in the opposite direction.




DISC FLOWERS
The radially symmetrical flowers of the head in Compositae, as distinguished from the ligulate ray flowers.



DISCHARGE AREA
Area where groundwater moves toward or is delivered to the soil surface.



DISCOID
Having the form of a disk; discoid flower; a compound flower not radiated but with tubular florets.



DISCOUNTING THE ILLUMINANT
Illumination of the visual world tens to be non-uniform, and fluctuates. in order for the visual system to create a consistent perception of color and lightness it must somehow discount fluctuation and gradient in the lighting source.



DISCRETE COSINE TRANSFORM
A multiresolution image coding technique used in JPEG. DCT features are products of harmonic functions where j and k refer to postion along the hrizontal and vertical directions. Generates a series of transfrom coefficient corresonding to the DCT features in the image. (See also JPEG).



DISEASE
Organisms suffer from disease when their normal function is impaired by some genetic disorder, or more often from the activity of a parasite or other organism living within them. Many diseases are caused by viruses, bacteria, or fungi.



DISPARITY GRADIENT
The ratio of the difference between two feature's disparities and their cyclopean separation. Steeply slanted surfaces have large disparity gradients. Human binocular fusion will only tolerate a disparity gradient of about 1.




DISPERSAL
Spread of a species to a new location. In many organisms, this happens at a particular stage in the life cycle, and is often crucial to the survival of the species. Organisms may disperse as spores, seeds, eggs, larvae, or adults.



DISPERSION
The process whereby a chemical, contained in water, deviates from the path that would be expected due to bulk flow.



DISPOSAL
The discharge, deposit, injection, dumping, spilling, leaking or placing of any hazardous waste into or on any land or water so that such hazardous waste or any constituent thereof may enter the environment or be emitted into the air or discharged into any waters, including ground water.



DISPOSAL FACILITY
a. (hazardous waste) A facility or part of a facility at which hazardous waste is intentionally placed into or on any water or land, and at which waste will remain after closure; b. (solid waste) A facility or part of a facility at which solid waste disposal occurs.



DISTAL
Farthest away from the point of attachment or origin.



DISTICHOUS
Two-ranked; in the case of plants with alternate leaves, the arrangement is such that 1st is directly below the 3rd.



DISTILLATION
Two-stage water treatment method: 1) the liquid is boiled, producing water vapor; 2) the water vapor is condensed, leaving most contaminants behind.



DISTRIBUTION
In toxicology, the transport and diffusion of an absorbed material within the body. The body distribution of a compound is a function of the size, water or fat solubility, and ionization, among other factors, associated with the material.



DIURNAL
Having a period or cycle of approximately one tidal day.



DIURNAL INEQUALITY
The difference in height of the two high waters or of the two low waters of each tidal day; also, the difference in speed between the two flood tidal currents or the two ebb currents of each tidal day.



DIURNAL RANGE
[See GREAT DIURNAL RANGE]



DIURNAL TIDE LEVEL
A tidal datum midway between mean higher high water and mean lower low water.



DIVARICATE
To branch or spread widely apart.



DIVERGENT
Separated from one another, having tips further apart than the bases



DIVERTICULATE
Having short offshoots approximately at right angles to axis.



DIVIDED
Referring to the blade of an appendage when it is cut into distinct divisions to, or almost to, the midvein.



DMAX
The largest displacement between successive presentations for which observers still obtain a coherent sense of motion. For larger steps the displaced object seems to disappear and then reappear at a different location. Increases with retinal eccentricity and is a function of the spatial frequencies in the image. Note that apparent motion can occur at distance much larger than Dmax.



DNA
[See DEOXYRIBONUCLEIC ACID]



DOCTRINE OF ISOMORPHISM
(See GESTALT PSYCHOLOGISTS).



DOLOMITE
A carbonate sedimentary rock composed of more than 50 percent of the mineral calcium-magnesium carbonate (CaMg(CO3)2).



DORMANCY
A period of suspended growth and metabolic activity. Many plants, seeds, spores, and some invertebrates become dormant during unfavorable conditions.



DORSAL
Pertaining to the back; the surface turned away from the axis.



DORSAL PATHWAY
One of two theorized systems of visual information processing. Information thought to progress toward the parietal cortex V1-> V2 -> MT -> MST -> STP. Functions in comprehension of spatial arrangement. (See also VENTRAL PATHWAY).



DOUBLE EBB
An ebb tidal current having two maxima of speed separated by a smaller ebb speed.



DOUBLE FLOOD
A flood tidal current having two maxima of speed separated by a smaller flood speed.



DOUBLE MEMBRANE
In mitochondria and plastids, there is a two-layered membrane which surrounds the organelle. This is believed to be the result of endosymbiosis, with the outer membrane coming from the eukaryotic cell, and the inner membrane belonging to the original prokaryote which was "swallowed".



DOUBLE TIDE
A double-headed tide, that is, a high water consisting of two maxima of nearly the same height separated by a relatively small depression, or a low water consisting of two minima separated by a relatively small elevation. Sometimes called an agger.



DOWN
Fine, soft feathers; soft, fine hair.



DOWNY
Covered with short, fine hairs.



DRAINAGE
Process of transporting surface water over a land area to a river, lake or ocean (surface drainage), or removal of water from a soil using buried pipelines that are regularly spaced and perforated (subsurface drainage).



DRAWDOWN
A lowering of the groundwater surface caused by withdrawal or pumping of water from a well.



DREDGING
Dredging is usually associated with the removal of loosened submerged deposits of sediments or rocky materials for the purpose of deepening a channel (or basin) or obtaining fill or aggregate for construction use.



DRIERS
Various compounds added to coatings to speed the drying.



DRIFT
[of current] The speed of the current.



DRIFT CURRENT
[See WIND DRIFT]



DRUPE
A fleshy or pulpy fruit with the inner portion of the pericarp hard or stony and enclosing the seed; usually 1-locular and 1-seeded, sometimes more than 1-locular and more than 1-seeded.



DRY COLORS
Powder-type colors to be mixed with water, alcohol or mineral spirits and resin to form a paint or stain.



DRYING OIL
An oil that when exposed to air will dry to a solid through chemical reaction with air [linseed oil, tung oil, perilla, fish oil, soybean oil].



DURA
Dura mater is the outer membrane covering the spinal cord and brain.



DYNAMIC METER
The former practical unit for geopotential difference (dynamic depth), equal to 10 geopotentials (dynamic decimeters).



DYNAMIC TOPOGRAPHY
[See GEOPOTENTIAL TOPOGRAPHY]



EAGRE
[See TIDAL BORE]



EARTH PIGMENTS
Those pigments that are obtained from the earth, including barytes, ocher, chalk and graphite.



EARTH TIDE
Periodic movement of the Earth's crust caused by gravitational interactions between the Sun, Moon, and Earth.



EBB AXIS
Average set of the current at ebb strength.



EBB CURRENT
The movement of a tidal current away from shore or down a tidal river or estuary.



EBB INTERVAL
The interval between the transit of the Moon over the meridian of a place and the time of the following ebb strength.



EBB STRENGTH
Phase of the ebb tidal current at the time of maximum speed.



EBBINGHAUS ILLUSION
Although the two central circles are the same size the one surrounded by smaller circles usually appears larger than the one surrounded by large circles.




ECCENTRICITY
Angular distance of a point on the retina from the center of the fovea




ECCENTRICITY OF ORBIT
Ratio of the distance from center to focus of orbit to the semimajor axis.



ECHINATE
Set with prickles; prickly, like a hedgehog; having sharp points.



ECLIPTIC
The intersection of the plane of the Earth's orbit with celestial sphere.



ECOLOGICAL APPROACH
Emphasizes the information which may be available in extended spatial and temporal pattern in the optic array to guide the actions of animals and people and to specify events of importance or interest as opposed to considering information just present in the retinal image




ECOLOGY
Branch of science concerned with the interrelationships of organisms and their environments esp. as manifested by natural cycles and rhythms, community development and structure, interaction between different kinds of organisms, geographic distributions and population alteration.



ECOSYSTEM
All the organisms in a particular region and the environment in which they live. The elements of an ecosystem interact with each other in some way, and so depend on each other either directly or indirectly.



EDAPHIC
Relating to, or determined by, conditions of the soil.



EDDY
A quasi-circular movement of water whose area is relatively small in comparison to the current with which it is associated.



EDGE INTEGRATION
Describes a model of lightness perception in which a region's lightness is computed by integrating over the contrast edges in an image. (See THE RETINEX ALGORITHM)



EDGE WAVES
Waves moving between zones of high and low breakers along the shoreline.



EFFERENT
Heading away. A system's efferent signals are those exiting to elsewhere. (As opposed to Afferent)




EFFLUENT
1. Wastewater that flows into a receiving stream by way of a domestic or industrial POINT SOURCE; 2. The discharge of a contaminant or contaminants with water from animal production or industrial facilities or waste water treatment plant.



EFFLUENT STREAM
[See GAINING STREAM]



EGG
1. A large gamete without flagellae that is fertilized by a sperm cell. An egg cell is also called an ovum; 2. A complex multicellular structure in which an animal embryo develops.



Eggbeater
[Synchronized Swimming] A rotary action of the legs used to support and propel the upper body in an upright position, leaving the arms free.



EGGSHELL
Gloss lying between semigloss and flat.



EHRENSTEIN ILLUSION
A series of radial lines create an illusory circle that appears to be brighter than the background.




EIGENGRAU
German word for 'intrinsic gray'. When both entire retinal images are stabilized, the observer does not perceive black but a non-descript gray fog.



EKMAN SPIRAL
A logarithmic spiral (when projected on a horizontal plane) formed by current velocity vectors at increasing depth intervals.



ELATER
A cell or part of a cell which assists in dispersing spores. The elaters change shape as they lose or acquire water, and they will then push against surrounding spores.



ELECTRIC TAPE GAUGE
A gauge consisting of a graduated Monel metal tape on a metal reel (with supporting frame)., voltmeter, and battery.



ELIMINATION
One of the final processes in the harmonic analysis of tides in which preliminary values for the harmonic constants of a number of constituents are cleared of the residual effects each other.



ELLIPTIC
An outline that is oval, narrowed to rounded at the ends and widest at about the middle (as the outline of a football); ellipsoid, a solid with an elliptical outline.



EMARGINATE
Said of leaves, sepals, or petals, and other structures that are notched at the apex.



EMBRYO
Once a zygote begins to undergo cellular divisions, it becomes an embryo.



EMBRYOPHYTE
Synonym for Plantae. It includes all green photosynthetic organisms which begin the development of the sporophyte generation within the archegonium.



EMERGE
To rise out of a fluid or other covering.



EMERGENT
Any of various plants (as a cattail) rooted in shallow water and having most of the vegetative growth above the water.



EMERGENT PLANT
A plant that grows in shallow water with the root system submerged under the water and the upper vegetation rising above the water.



EMERSED
Standing out of or rising above a surface as an aquatic plant with flower stalk emersed.



EMERSED PLANTS
Plants growing with their roots and a portion of the shoot below the water and the remainder of the shoot above the surface of the water.



EMMERT'S LAW
A monocular after-image is located on any surface to which a subject fixates while the after -image is present.x The perceived size of the after-image increases as the perceived distance of the surface increase. Shows that monocular cues may be insufficient to estimate an object's length.




EMMETROPIA
An eye whose image is focused on the retina, rather than in front of behind it. (As opposed to Hyperopia and Myopia)



EMULSION
A mixture of solids suspended in a liquid.



EMULSION PAINT
Coating in which resins are suspended in water, then flow together with the aid of an emulsifier.



ENAMEL
Broad classification of paints that dry to a hard, usually glossy finish.



ENATION
An abnormal growth of an organ or of an excresence upon any part of a plant.



ENATIONS
Flaps of tissue such as those found on psilophytes.



END-CUTTING
A compensatory process needed to prevent featural quality from flowing out of the percepts of all line endings and corners as orientationally tuned input masks are insensitive to orientation at the ends of scenic lines and corners.



END-INHIBITION
A property of some cells in the visual cortex which respond strongly to either an edge, a bar or a slit which ends within the receptive field.




END-STOPPED CELL
An orientation selective cell which is also sensitive to the end of a line or edge, responding to short but not long lines or edge stimuli.




ENDANGERED SPECIES
Any creature "in danger of extinction throughout all or a significant portion of its range".
[Endangered Species Act] --> federal law establishing procedures for the listing of species and plants or animals as endangered or threatened. The law also prohibits federal agencies from engaging in projects that place in jeopardy the continued existence of species that are threatened or endangered.



ENDEMIC
A plant that is native to a particular country or region; not introduced or naturalized.



ENDOCARP
The inter layer of the wall of a matured ovary; when its texture differs from the outer wall, it may be hard and stony, membranous, or fleshy.



ENDODERMIS
Literally "inner skin", this is a layer of cells which surrounds the central core of vascular tissue, and which helps to regulate the flow of water and dissolved substances.



ENDOPLASMIC RETICULUM
Network of membranes in eukaryotic cells which helps in control of protein synthesis and cellular organization.



ENSIFORM
Having sharp edges and tapering to a slender point; having a shape suggesting a sword.



ENTIRE
Having a margin devoid of any indentations, teeth, or lobes.



ENTOMOPHILOUS
Pollination by insects.



ENTOMOPHILY
Seed plants which are pollinated by insects are said to be entomophilous.



ENVIRONMENT
The place in which an organism lives, and the circumstances under which it lives. Environment includes measures like moisture and temperature, as much as it refers to the actual physical place where an organism is found.



ENZYME
Complex protein which helps to speed biochemical reactions. Enzymes are important in the construction and degradation of other molecules.



EPHEMERAL
Referring to an organ living a very short time, usually a day or less; lasting a very short time.



EPICAPSULAR STARS
Remnants left on the eye of the hyaloid canal, from development in the womb.




EPICENTER
Point on the Earth's surface directly above the focus of an earthquake.



EPIDERMIS
The outermost layer of cells; the "skin" of a plant, covering the leaves, stem, and roots. This tissue often contains specialized cells for defense, gas exchange, or secretion.



EPIGYNOUS
Growing upon the top of the ovary or seeming to do so, as petals, sepals, and stamens.



EPIGYNY
The condition of being epigynous.



EPIPETALOUS
Having stamens inserted on petals.



EPIPHYTE
A plant which grows upon another plant. The epiphyte does not "eat" the plant on which it grows, but merely uses the plant for structural support, or as a way to get off the ground and into the canopy environment.



EPIPOLAR LINE
For a given point in space, this is the line on which the point will fall in the opposite eye. This line is tilted out of the horizontal unless the eyes are fixated on a very distant object.




EPOCH
[See PHASE LAG]



EPOXY
Extremely tough and durable synthetic resin used in some coatings.



EQUATION OF TIME
Difference between mean and apparent time.



EQUATORIAL TIDAL CURRENTS
Tidal currents occurring semimonthly as a result of the Moon being over the Equator.



EQUATORIAL TIDES
Tides occurring semimonthly as a result of the Moon being over the Equator.



EQUILIBRIUM ARGUMENT
The theoretical phase of a constituent of the equilibrium tide.



EQUILIBRIUM THEORY
A model under which it is assumed that the waters covering the face of the Earth instantly respond to the tide-producing forces of the Moon and Sun to form a surface of equilibrium under the action of these forces.



EQUILIBRIUM TIDE
Hypothetical tide due to the tide producing forces under the equilibrium theory.



EQUILUMINANT STIMULI
Visual stimuli that vary only in color but not in luminance. Stereopsis and motion perception disappear at equiluminance indicating the presence of separate processing channels for color, motion and stereopsis.




EQUINOCTIAL
The celestial equator.



EQUINOCTIAL TIDES
Tides occurring near the times of the equinoxes.



EQUINOXES
The two points in the celestial sphere where the celestial equator intersects the ecliptic; also, the times when the Sun crosses the equator at these points.



EQUIPOTENTIAL SURFACE
[See GEOPOTENTIAL SURFACE]



EQUITANT
Overlapping; said of leaves whose bases overlap the leaves within or above them, as in the Iris.



EQUIVALENCE CLASSES
(See NULL SETS).



EROSE
Having small irregular notches in the margin, as if gnawed.



EROSION
1. Processes (mechanical and chemical) responsible for the wearing away, loosening, and dissolving of materials of the Earth's crust; 2. The process or series of processes that removes soils, crop residues, and organic matter from the land surface in runoff waters, or by wind.



ESSENTIAL FLOWER PARTS
The stamen and pistil organs of the flower that are required for pollination.



ESTUARY
1. An embayment of the coast in which fresh river water entering at its head mixes with the relatively saline ocean water; 2. An inlet or arm of the sea; especially the wide mouth of a river, where the tide meets the current. pl. estuaries.



EUKARYOTIC
Literally "true nucleus", the term applies to all protists, plants, animals, and fungi. Eukaryotic cells have internal membranes which partition them into regions for different functions, such as mitochondria, plastids, the ER, Golgi apparatus, etc. They also possess a cytoskeleton which helps them control their shape.



EULARIAN MEASUREMENT
Observation of a current with a device fixed relative to the flow.



EUSTATIC SEA LEVEL RATE
The worldwide change of sea level elevation with time.



EUSTELE
When a plant's vascular tissue develops in discrete bundles, it is said to have a eustele.



EUTROPHIC
The gradual increase in nutrients in a body of water. Natural eutrophication is a gradual process, but human activities may greatly accelerate the process.



EUTROPHICATION
1. The addition of excessive plant nutrients to a river, lake stream, or other body of water. The nutrients in excess are usually nitrates or phosphates, and the leads to prolific growth of aquatic plants; 2. The process of becoming eutrophic; 3. The process of surface water nutrient enrichment causing a water body to fill with aquatic plants and algae.



EVAPOTRANSPIRATION
The process of changing soil water into water vapor through the combination of soil evaporation and plant water use, or transpiration.



EVECTION
A perturbation of the Moon depending upon the alternate increase and decrease of the eccentricity of its orbit, which is always a maximum when the Sun is passing the Moon's line of apsides and a minimum when the Sun is at right angles to it.



EVEN-PINNATE
Said of compound leaves having an even number of leaflets, this is usually easily determined because there is a pair terminally.



EXCRESCENCE
A normal outgrowth; a disfiguring addition.



EXCURRENT
Projecting beyond the tip, as the midrib of a leaf or bract.



Execution
[Synchronized Swimming] The performance level of the skills demonstrated.



EXEMPTED AIR CONTAMINANT
A source that has been exempted from construction and operating permits by the Division of APC.



EXEMPTED HAZARDOUS WASTES
Wastes that have been exempted from RCRA but may still be subject to TDEC regulations.



EXFOLIATE
Peeling off in thin layers, shreds, or plates, as the bark of some trees.



EXINE
The outer of two layers forming the wall of certain spores (as pollen grains) - called also exosporium.



EXOCARP
The outer layer of the wall of a matured ovary.



EXSERT
To put forth; to thrust out; to protrude.



EXSERTED
Sticking out; extending beyond (some enclosing part).



EXSTIPULATE
Having no stem.



EXTENDER
Ingredients added to paint to increase coverage, reduce cost, achieve durability, alter appearance, control rheology and influence other desirable properties.



EXTRACELLULAR MATRIX
Region outside of metazoan cells which includes compounds attached to the plasma membrane, as well as dissolved substances attracted to the surface charge of the cells. The ECM functions both to keep animal cells adhered together, and well as buffering them from their environment.



EXTRASTRIATE CORTEX
Region of primate cerebral cortex anterior to striate cortex.



EXTREME HIGH WATER
The highest elevation reached by the sea as recorded by a tide gauge during a given period.



EXTREME LOW WATER
The lowest elevation reached by the sea as recorded by a tide gauge during a given period.



EXTRINSIC TERMINATORS
Those terminators that are not created by the end of the object itself. Rather they are due to occlusion by another surface. Such terminators play less of a role in determining the perceived direction of motion than do intrinsic terminators (See TERMINATORS).



EXTRUSIVE
Igneous. Antonym of intrusive.



EYESPOT
1. A concentrated patch of photoreceptor cells on the skin present in some species; 2. Light-sensitive organelle found in many groups of protists, and in some metazoans.




FACT SHEET
A document that briefly sets forth the principal facts and the significant factual, legal, methodological and policy questions considered in preparing the draft permit.



FALCATE
Curved like a sickle.



FALSE TARGET PROBLEM
(See CORRESPONDENCE PROBLEM)



FAR-SIGHTEDNESS
(See HYPEROPIA).



FARINACEOUS
Containing flour; starchy; mealy.



FARINOSE
Full of meal; mealy; covered with a white, powdery substance.



FARM POND
Any impoundment used exclusively to provide water for agricultural and domestic purposes such as livestock and poultry watering, irrigation of crops, recreation and conservation for the owner or occupant of the farm.



FASCICLE
A small bundle or tuft, as of fibers, leaves, etc.



FASTIGIATE
Branches close to stem and erect.



FAULT
A fracture or zone of fractures in rocks of mappable size along which there has been displacement of one side relative to the other.



FEATURE BINDING
The binding of features processed by different systems (audio, visual) or of different subsystems (motion, depth, color) to create a unified conscious percept.



FEATURE MATCHING
In Binocular Vision and Stereopsis, disparity can be extracted from an image if features in the two corresponding binocular images are matchable e.g. lines to lines, dots to dots.




FECAL COLIFORM
A portion of the coliform bacteria group originating in the intestinal tract of warm-blooded animals that pass into the environment as feces.



FECHNER'S PARADOX
The fact that a monocular view may look brighter than a binocular view. Suppose that a scene is viewed through both eyes but that one eye sees it through a neutral filter that attenuates all wavelengths by a constant ratio. The filter does not distort the reflectances or ratios of light reaching the eye, but only its absolute intensity. If the filtered eye is entirely occluded the scene looks brighter and more vivid than with the filter despite the fact that less total light is reaching the two eyes and the
reflectances are still the same.




FELSIC
Term used to describe the amount of light-colored feldspar and silica minerals in an igneous rock. Complement of mafic.



FEMALE
In organisms with separate sexes, the one which produces eggs.



FEN
Low land covered wholly or partially with water but producing sedge, coarse grasses, or other aquatic plants; boggy land; a moor or marsh; plant community on alkaline, neutral, or slightly acid peat.



FENESTRATED
A type of leaf anatomy with small perforation or transparent spots. Confined to a few tropical monocotyledons which grow on the island of Madagascar.



FERTILIZATION
The process by which an egg is made capable of generating offspring. It is often synonymous with syngamy.



FIBER
Elongated and thickened cell found in xylem tissue. It strengthens and supports the surrounding cells.



FIELD CAPACITY
The amount of water a soil contains after rapid drainage has ceased.



Figure
[Synchronized Swimming] A combination of body positions and transitions performed in a prescribed manner.



FILAMENT
1. Long chain of proteins, such as found in hair, muscle, or in flagella.; 2. The stalk bearing the anther.



FILIFORM
Thread-like, long and very slender.



FILLING-IN THEORY
Idea that the brightness and color of interiors of homogeneous regions are determined by a process of lateral spread of neural activation that is initiated by units responding to abrupt changes in luminance and wavelength.



FILM BUILD
Amount of thickness produced in an application.



FILM THICKNESS
Depth or thickness of the dry coating in millimeters.



FIMBRIATE
Cut into regular segments and appearing fringed at the margins.



FIRE RESISTANCE
The ability of a coating to withstand fire or to protect the substrate to which it is applied from fire damage.



FIRE RETARDANT
A coating which will (1) reduce flame spread, (2) resist ignition when exposed to high temperature or (3) insulate the substrate and delay damage to the substrate.



FIRST-ORDER MOTION MECHANISMS
Captures motion information from moving objects or features that differ from the background in luminance. (See also SECOND-ORDER MOTION MECHANISMS).



FIRST REDUCTION
A method of determining high and low water heights, time intervals, and ranges from an arithmetic mean without adjustment to a long-term series through simultaneous observational comparisons.



FISSION
Division of single-celled organisms, especially prokaryotes, in which mitosis does not occur. Also used to refer to mitosis in certain unicellular fungi.



FISTULA
Pathological or artifical pipe-like opening; water-conducting vessel - alt. trachea.



FISTULOSE
Same as fistulous.



FISTULOUS
Having the form or nature of a fistula.



FIXATION
Alignment of the eyes so that the image of the fixated target falls on the area centralis. For animals with immobile eyes the alignment of the head towards the fixated target



FLABELLATE
Fan-shaped.



FLACCID
Weak, limp, soft, or flabby; leaves that do not have enough water and are about to wilt or are wilting.



FLAGELLIN
Protein which is the primary component of prokaryotic flagella.



FLAGELLUM
Hair-like structure attached to a cell, used for locomotion in many protists and prokaryotes. The prokaryotic flagellum differs from the eukaryotic flagellum in that the prokaryotic flagellum is a solid unit composed primarily of the protein flagellin, while the eukaryotic flagellum is composed of several protein strands bound by a membrane, and does not contain flagellin. The eukaryotic flagellum is sometimes referred to as an undulipodium.



Flamingo
[Synchronized Swimming] A position where one leg is extended perpendicular to the surface while the other leg is drawn to the chest, with the lower leg parallel to the surface and the face at the surface.



FLAT
A surface that scatters or absorbs the light falling on it so as to be substantially free from gloss or sheen (0-15 gloss on a 60-degree gloss meter).



FLICKER
Alternating levels of brightness. (See also CRITICAL FLICKER FREQUENCY and FLICKER PHOTOMETRY EXPERIMENT)



FLICKER PHOTOMETRY EXPERIMENT
Stimuli consisting of a pair of different color test lights alternate. When the lights alternate slowly the pattern appears to change between the colors of the two lights. When the lights alternate rapidly observers fail to see the color modulation and instead perceive a dark-light modulation. Demonstrates that the temporal resolution for distinguishing blue-yellow is less than red-green which in turn is less than light-dark.




Float
[Synchronized Swimming] A surface formation where between two and eight swimmers are connected horizontally.



FLOAT WELL
A stilling well in which the float of a float-actuated gauge operates [ See alsi STILLING WELL].



FLOATER
A blurry spot that appears to float around in the eye but does not block vision. The blur is the result of debris from the vitreous humour casting a shadow on the retina.



FLOCCOSE
Said of pubescence which gives the impression of irregular tufts of cotton or wool.



FLOCCULATION
In wastewater treatment, the rapid mixing of chemicals into the wastewater to enhance the formation of FLOC.



FLOOD AXIS
The average set of the tidal current at strength of flood.



FLOOD CURRENT
The movement of a tidal current toward the shore or up a tidal river or estuary.



FLOOD INTERVAL
The interval between the transit of the Moon over the meridian of a place and the time of the following flood strength.



FLOOD STRENGTH
Phase of the flood tidal current at the time of maximum speed. Also, the speed at this time.



FLORESCENCE
Bursting into bloom, alt. anthesis.



FLORET
One of the small individual flowers of a crowded inflorescence such as capitulum; flower with lemma and palea, of grasses; alt. floscule.



FLORICANE
The stem at flowering and fruiting stage (of a bramble, Rubus).



FLOSCULE
a small flower; a floret.



FLOW
The British equivalent of the United States total current.



FLOWER
The part of a plant containing or consisting of the organs of reproduction, either together in a monoclinous flower or separate in male and female flowers.



FLUSHING TIME
The time required to remove or reduce (to a permissible concentration) any dissolved or suspended contaminant in an estuary or harbor.



FOCAL LENGTH
Relates the distance between an image source and a lens ds and the distance of the lens to the image di by the lenses focal length f.



FOCAL VISION
The role of vision involved in the examination and identification of objects associated with the fovea and exploratory eye movements. (As opposed to Ambient Vision)




FOCUS
The initial point within the Earth that ruptures in an earthquake, directly below the epicenter.



FOLD
Bent rock strata.



FOLIACEOUS
Having the form or texture of a foliage leaf; thin and leaf-like; bearing leaves.



FOLLICLE
A dry dehiscent fruit formed of one carpel, and dehiscing along one side.



FOOD CHAIN
All the interactions of predator and prey, included along with the exchange of nutrients into and out of the soil. These interactions connect the various members of an ecosystem, and describe how energy passes from one organism to another.



FOOD WEB
[See FOOD CHAIN]



FORCED DRY
Baking the paint between room temperature and 150ø F to speed the drying process.



FORCED WAVE
A wave generated and maintained by a continuous force.



FORTNIGHT
The time elasped between the new and full moons. Half a synodic month of 14.765,294 days.



FOSSIL
Any evidence of past life, including remains, traces, imprints as well as life history artifacts. Examples of artifacts include fossilized bird's nests, bee hives, etc.



FOVEA
The area of the retina associated with the highest concentration of cones and therefore the highest acuity. Humans move their eyes so that images of interest are projected onto their foveas.



FOVEOLA
The center of the fovea.



Free routine
[Synchronized Swimming] A routine where the choreography and choice of music is completely free.



FREE WAVE
A wave that continues to exist after the generating force has ceased to act.



FRESH WEIGHT
Same as wet weight. Generally not a useful measurement for aquatic plants.



FROND
A leaf, especially of fern or palm; a leaf-like expansion.



FRUGIVORE
Animal which primarily eats fruit. Many bats and birds are frugivores.



FRUIT
The developed ovary of the flower containing ripe seeds, whether fleshy or dry, often used to include other associated parts such as a fleshy receptacle, then called a false fruit.



FRUSTULE
The mineral "skeleton" of a diatom or other unicellular organism.



FRUTESCENT
Shrubby or becoming shrubby.



FUCOXANTHIN
Yellowish-brown pigment found in some members of the Chromista, including kelps and diatoms.



Full twist
[Synchronized Swimming] A rotation of 360 degrees at sustained height.



FULL-WAVE RECTIFICATION
A signal which shows a positive response to both the positive and negative parts of a sinusiod (i.e. frequency doubling). Many complex cells show this to contrast reversing patterns. (See also HALF-WAVE RECTIFICATION).



FUNICLE
Funiculus.



FUNICULUS
The stalk of an ovule. pl. funiculi.



FUSIFORM
Shaped like a spindle; thick, tapering at both ends.



GABBRO
Highly mafic igneous plutonic rock, typically dark in color; rough plutonic equivalent of basalt.



GAINING STREAM
A stream or portion of a stream where flow increases because of discharge from groundwater.



GALOFARO
A whirlpool in the Strait of Messina; at one time called Charybdis.



GALVANIZING
Process in which a thin coating of zinc is applied to iron or steel to prevent rust.



GAMETE
Reproductive cells which fuse to form a zygote. Gametes are haploid, and may be differentiated into egg and sperm.



GAMETOPHYTE
The gamete-forming haploid phase in the alternation of plant generations.



GAMOPETALOUS
Having the petals united so as to form a tubelike corolla. Same as sympetalous.



GAMOSEPALOUS
Having the sepals united.



GANGLION CELL
Output neuron of the retina. Axons form the optic nerve. Divided into several different classifications by morphological and physiological features for cats and primates. (See also ON-CENTER CELLS and OFF-CENTER CELLS).



GANGLION CELL LAYER
(See RETINAL LAYERS).



GANZFELD PHENOMENON
A uniformly illuminated surface of a uniform field (a ganzfeld) quickly disappears from visual perception and one experiences a gray fog.



GAS PURGED PRESSURE GAUGE
A type of analog tide gauge in which gas, usually nitrogen, is emitted from a submerged tube at a constant rate.



GAUSSIAN FILTER
Algorithm smoothing spatial or temporal variation in an image by averaging neighboring values of light intensity, the contribution of values to the average being weighted according to a Gaussian function.



GELB-EXPERIMENT
A spinning black disc is illuminated by a projector in a darkly illuminated room. The disk appears to be white until a small white piece of paper is placed in front of the projected light at which time the true color of the disk is perceived (i.e. black).




GEMMA
A bud or outgrowth of a plant which develops into a new organism. A leaf bud rather than a flower bud.



GEMMATES
Buds or outgrowths of a plant which develop into a new individual.



GENERALIST
Organism which can survive under a wide variety of conditions, and does not specialize to live under any particular set of circumstances.



GENERALIZED CONE
A surface representation created by moving a cross-section of a constant shape but variable size along an axis.



GENERATOR
Any person, by site, whose act or process produces hazardous waste identified or listed in SWM Rule 1200-1-11-.02 or whose act first causes a hazardous waste in a calendar month.



GENERIC VIEW
A view of an object that is not special. In other words, the view won't change drastically with small perturbations in lighting or viewing direction. (As opposed to Accidental View).



GENICULATE
Bent like a knee; bent abruptly at the nodes.



GENICULOSTRIATE PATHWAY
Pathway from the retina via the LGN to the striate cortex



GENOTYPE
The genetic constitution of an individual.



GENUS
a taxonomic group consisting of closely related species, genera being grouped into families; plural - genera; a. - generic.



GEOMORPHOLOGY
The study of the nature and origin of the land features of the earth.



GEONS
Geometric ions. A set of basic shape primitive (wedges, cylinders) from which complex objects can be described.



GEOPHYTE
Plants with an underground dormant part such as a tuber, bulb, rhizome, etc. to help the plant survive adverse conditions.



GEOPOTENTIAL
The unit of geopotential difference, equal to the gravity potential of 1 meter squared per second squared.



GEOPOTENTIAL ANOMALY
The excess in geopotential difference over the standard geopotential difference [at a standard specific volume at 35 parts per thousand (°/..) and 0 degrees C] between isobaric surfaces.



GEOPOTENTIAL DIFFERENCE
The work per unit mass gained or required in moving a unit mass vertically from one geopotential surface to another.



GEOPOTENTIAL SURFACE
A surface that is everywhere normal to the acceleration of gravity.



GEOPOTENTIAL TOPOGRAPHY
The topography of an equiscalar (usually isobaric) surface in terms of geopotential difference.



GEOSTROPHIC FLOW
A solution of the relative hydrodynamic equations of motion in which it is assumed that the horizontal component of the Coriolis force is balanced by the horizontal component of the pressure gradient force.



GERMINATION
The process by which a seedling emerges and develops from a seed, or by which a sporeling emerges and develops from a spore.



GESTALT PSYCHOLOGISTS
The whole is greater than the parts



GIBBERELLINS
Growth hormones that accelerate shoot growth. First discovered in the fungus Gibberella fujikuroi, and later in other plants.



GIBBOUS
A distended, rounded swelling on one side, as on a calyx or corolla tube or segment.



GLABRATE
Becoming glabrous with age.



GLABROUS
With a smooth, even surface; without hairs.



GLADE
Open space surrounded by woods or a forest; a marshy and usually low-lying area; a periodically inundated grassy marsh often running between adjacent slopes; a marshy area bounding or forming the headwaters of a stream.



GLAND
A secreting part or appendage.



GLANDULAR
Having or bearing secreting organs, glands, or trichomes.



GLANDULAR-PUBESCENT
Hairs or trichomes capitate and secretory.



GLASS
A non-crystaline rock that results from very rapid cooling of magma.



GLASS PATTERN
If one takes a random set of dots and a slightly rotated copy of the same set of dots, local groupings create a globally coherent pattern.



GLAUCOMA
A symptomatic condition characterized by raised intra-ocular pressure, visual field loss, enlargement of the blind spot and changes in the appearance of the optic nerve head. If left untreated ganglion cell axon death may be caused by prolonged exposure of the eye to elevated introcular pressure.



GLAUCOUS
Bluish green; covered with a pale green bloom.



GLOBOSE
Rounded; almost spherical; globular.



GLOMERATE
To gather or wind into a ball; growing, collected or arranged in a rounded mass, as glands, flowers, etc.; clustered.



GLOMERULE
A condensed cyme of almost sessile flowers; a compact cluster as of spores.



GLOSS
The luster or shininess of paints and coatings.



GLOSS METER
A device for measuring the light reflectance of coatings.



GLUCOSE
Simple sugar, and the primary product of photosynthesis. It is polymerized to make cellulose and chitin.



GLUME
A chaffy or membranous bract, a bract at the base of a grass inflorescence or spikelet.



GLUTINOUS
Having a sticky, moist surface; a gluey or sticky exudation.



GLYCOPROTEIN
A membrane-bound protein which has attached branching carbohydrates. These may function in cell-cell recognition, such as in human blood groups and immune system response, as well as in resisting compression of cells.



GOLGI APPARATUS
Eukaryotic organelle which package cell products, such as enzymes and hormones, and coordinate their transport to the outside of the cell.



GRADIENT FLOW
A solution of the relative hydrodynamic equations of motion in which only the horizontal Coriolis, pressure gradient, and centrifugal forces are considered.



GRAIN
1. The texture of wood, produced by the kinds of xylem cells present; 2. The fruit of a member of the grasses.



GRAINS PER GALLON
A unit of measurement often used to describe water hardness. One grain per gallon is approximately equal to 17 ppm of various cations.



GRANITE
Highly felsic igneous plutonic rock, typically light in color; rough plutonic equivalent of rhyolite. Granite is actually quite rare in the U.S.; often the term is applied to any quartz-bearing plutonic rock.



GRANODIORITE
Igneous plutonic rock, less felsic than granite, typically light in color; rough plutonic equivalent of dacite.



GRASSLAND
Region in which the climate is dry for long periods of the summer, and freezes in the winter. Grasslands are characterized by grasses and other erect herbs, usually without trees or shrubs. Grasslands occur in the dry temperate interiors of continents, and first appeared in the Miocene.



GRAVITATIONAL TIDE
[See EQUILIBRIUM TIDE]



GRAVITY WAVE
A wave for which the restoring force is gravity.



GRAYWACKE
Sandstone composed of poorly sorted angular clasts.



GREAT DIURNAL RANGE
The difference in height between mean higher high water and mean lower low water.



GREAT TROPIC RANGE
The difference in height between tropic higher high water and tropic lower low water.



GREENWICH ARGUMENT
Equilibrium argument computed for the meridian of Greenwich.



GREENWICH INTERVAL
An interval referred to the transit of the Moon over the meridian of Greenwich as distinguish from the local interval which is referred to the Moon's transit over the local meridian.



GREGORIAN CALENDAR
The modern calendar in which every year divisible by 4 (excepting century years) and every century year divisible by 400 are bissextile (or leap) years with 366 days.



GROUNDWATER
Water that occupies voids, cracks, or other spaces between particles of clay, silt, sand, gravel or rock within the saturated formation.



GROUNDWATER MINING
The removal of groundwater from an aquifer in excess of the rate of natural or artificial recharge.



GROUNDWATER RECHARGE
The process where water enters the soil and eventually reaches the saturated zone.



GUARD CELLS
Pair of cells which surround a stomate and regulate its size by altering their shape.



GULDER
Local name given to the double low water occurring on the south coast of England.



GUTTATION
Formation of drops of water on plants from moisture in air; the process of water being exuded from hydathodes at the enlarged terminations of veins around the margins of the leaves.



GYMNOSPERM
Generally any seed plant which does not produce flowers. The term may or may not exclude the pteridosperms.



GYMNOSPERMAE
An important division of the plant kingdom, being woody plants with alternation of generations, having the gametophyte retained on the sporophyte and seeds produced on the surface of the sporophylls and not enclosed in an ovary.



GYNAECIUM
The female organs of the flower, consisting of one or more carpels forming one or several ovaries with their stigmas and styles.



GYNECANDROUS
Having staminate and pistillate flowers in the same spike or spikelet, the latter above the former.



GYNOECIUM
The pistil or pistils of a flower, taken collectively; gynaecium.



GYNOPHORE
A stalk supporting the ovary.



GYNOSTEGIUM
A protective covering for a gynaecium, especially as formed by the union of stamens and style.



GYNOSTEMIUM
The central reproductive stalk of an orchid, which consists of a stamen and pistil fused together.



HABIT
The external appearance or way of growth of a plant, e.g. climbing, erect, bushy, etc.; the tendency of a plant to grow in a certain way.



HABITAT
1. The place and conditions in which an organism lives; 2. the locality or external environment in which a plant lives.



HALF-TIDE LEVEL
A tidal datum. The arithmetic mean of mean high water and mean low water.



Half twist
[Synchronized Swimming] A rotation of 180 degrees at sustained height.



HALF-WAVE RECTIFICATION
A signal which follows only the positive part of a sinusoid and has zero-response to the negative part. Many simple cells show half-wave rectification to contrast reversing patterns. (See also FULL-WAVE RECTIFICATION).



HALOCLINE
A layer in which the salinity changes significantly (relative to the layers above and below) with depth.



HALOPHILE
Organism which lives in areas of high salt concentration. These organisms must have special adaptations to permit them to survive under these conditions.



HALOPHYTE
Any species capable of tolerating 0.5% or more NaCl.



HAPLOID
Having a single set of chromosomes in the nucleus of each cell. Mosses, and many protists and fungi, are haploid.



HAPLOID-DIPLOID LIFE CYCLE
Occurs when a multicellular diploid phase, or sporophyte, alternates with a multicellular haploid phase, or gametophyte. Only plants and certain algae possess this kind of life cycle, which is also called "alternation of generations".



HAPLOID LIFE CYCLE
Occurs when the only multicellular stage in an organism's life cycle is haploid.



HAPLOPHYTE
Having the number of chromosomes characteristic of the gametes for the organism.



HAPLOSCOPIC STIMULATION
Different stimuli for the two eyes.



HAPTERON
Holdfast, specialized root-like projections that function to anchor a plant.



HAPTONEMA
Peg-like structure unique to the Prymnesiophyta; its function is not known.



HARDENER
Curing agent for epoxies or fiberglass.



HARMONIC ANALYSIS
The mathematical process by which the observed tide or tidal current at any place is separated into basic harmonic constituents.



HARMONIC ANALYZER
A machine designed for the resolution of a periodic curve into its harmonic constituents.



HARMONIC CONSTANTS
The amplitudes and epochs of the harmonic constituents of the tide or tidal current at any place.



HARMONIC FUNCTION
In its simplest form, a quantity that varies as the cosine of an angle that increases uniformly with time.



HARMONIC PREDICTION
Method of predicting tides and tidal currents by combining the harmonic constituents into a single tide curve.



HARMONIC REDUCTION
[See HARMONIC ANALYSIS]



HARMONIC TIDE PLANE
[See INDIAN SPRING LOW WATER]



HASTATE
Spear shaped, more or less triangular with the two basal lobes divergent.



HAZARD CRITERIA
The characteristics of waste that make it hazardous, i.e., ignitable, toxic, corrosive, reactive, etc.



HAZARDOUS SUBSTANCE
The list of hazardous substances includes hazardous wastes, hazardous air pollutants, water pollutants. and other substances listed in Section 101 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA).



HEAD
The difference in water level at either end of a strait, channel, inlet, etc.



HEAD OF TIDE
The inland or upstream limit of water affected by the tide.



HEMICRYPTOPHYTE
A perennial plant having its overwintering buds located at the soil surface.



HEMINEGLECT
A condition following damage to the parietal stream of one hemisphere in which individuals are unaware of stimuli from the hemifield that projects to that hemisphere.



HEMOGLOBIN
protein complex found in the blood of most chordates and the roots of certain legumes. It binds oxgen molecules, and in chordates serves as the means by which the oxygen is supplied to the cells of the body.



HEPA VACUUM
High-efficiency particulate air-filtered vacuum designed to remove lead- contaminated dust.



HERB
Any seed plant whose stem withers away to the ground after each season's growth; a seed plant with a green, non-woody stem.



HERBAGE
Herbs collectively; the green foliage and juicy stems of herbs.



HERBIVORE
Literally, an organism that eats plants or other autotrophic organisms. The term is used primarily to describe animals.



HERMANN GRID ILLUSION
Dark blobs appear at the intersections of a black rectangles except when viewed foveally.




HETEROPHYLLOUS
The presence on a single individual of two or more distinct leaf shapes. These leaves may differ markedly in shape, yet have similar gross anatomical organization.



HETEROSPORANGIATE
Producing two different kinds of sporangia, specifically microsporangia and megasporangia. [compare HETEROSPOROUS].



HETEROSPOROUS
Producing two different sizes or kinds of spores. These may come from the same or different sporangia, and may produce similar or different gametophytes. [contrast with homosporous, and compare with heterosporangiate].



HETEROZYGOTE
An organism or cell having two different alleles at corresponding loci on homologous chromosomes.



HIBERNACULUM
A plant organ such as a bud, rhizome, turion, etc. which allows a plant to live through adverse conditions



HIGH TIDE
[See HIGH WATER]



HIGH WATER
The maximum height reached by a rising tide.



HIGH WATER INEQUALITY
[See DIURNAL INEQUALITY]



HIGH WATER INTERVAL
[See LUNITIDAL INTERVAL]



HIGH WATER LINE
The intersection of the land with the water surface at an elevation of high water.



HIGH WATER MARK
A line or mark left upon tide flats, beach, or along shore objects indicating the elevation of the intrusion of high water.



HIGHER HIGH WATER
The highest of the high waters (or single high water) of any specified tidal day due to the declination Al effects of the Moon and Sun.



HIGHER LOW WATER
The highest of the low waters of any specified tidal day due to the declination.



HILUM
The scar on a seed marking the place where it was attached to the seed stalk.



HIRSUTE
Set with bristles; hairy; shaggy.



HISPID
Having stiff hairs, spines, or bristles.



HISTONES
proteins attached to the DNA of eukaryotes which allows it to be packaged into chromosomes.



HOLDFAST
Anchoring base of an alga.



HOLLOW FACE ILLUSION
A concave hollow mask of a face viewed from a few feet gives the impression of a normal face. The cognitive interpretation overrides the stereoscopic information.



HOMOSPOROUS
Producing only one size or kind of spore. [Contrast with HETEROSPOROUS].



HORIZONTAL CELLS
Cells in the retina connected via gap junctions that mediate lateral information transfer over large distances.



HORNER'S SYNDROME
Contraction of the pupil, enophthalmos (recession of the eyeball into the orbit), and sometimes loss of sweating over the affected side of the face. Due to paralysis of the cervical sympathetic nerve trunk.



HOROPTER
For a given fixation point, the set of points on the retina that are perceived to have zero retinal disparity. The points sweep out an arc in space that intersects a fixated point in space.



HOST
Organism which serves as the habitat for a parasite, or possibly for a symbiont. A host may provide nutrition to the parasite or symbiont, or simply a place in which to live.



HUE
The perception of color. (See also SATURATION).



HYALINE
Of thin, membranous, transparent or translucent texture.



HYBRID
Any cross-bred plant; heterozygote.



Hybrid figure
[Synchronized Swimming] A combination of figure parts, body positions and transitions that come from mixed origin or composition.



HYDATHODES
An epidermal structure specialized for secretion, or for exudation, of water.



HYDRAULIC CONDUCTIVITY
A term used to describe the ease with which water moves through soil or a saturated geologic material.



HYDRAULIC CURRENT
A current in a channel caused by a difference in the surface elevation at the two ends.



HYDRAULIC GRADIENT
Slope of the water surface in an aquifer. The hydraulic gradient indicates the direction groundwater will flow.



HYDRIC
Characterized by an abundant supply of water.



HYDROGRAPHIC DATUM
A datum used for referencing depths of water and the heights of predicted tides or water level observations.



HYDROLOGIC CYCLE
The constant movement of water above, on, and below the earth's surface.



HYDROPHILIC
"Water loving". Hydrophilic compounds dissolve easily in water, and are usually polar.



HYDROPHILY
Water pollination.



HYDROPHOBIC
"Water fearing". Hydrophobic compounds do not dissolve easily in water, and are usually non-polar. Oils and other long hydrocarbons are hydrophobic.



HYDROPHYTE
An aquatic plant living on or in water.



HYDROPOTE
A cell or cell group found on the lower epidermis of some species such as Nymphaea. These cells are thought to function in the uptake of ions from the water.



HYPANTHIUM
An expansion of the receptacle of a flower that forms a saucer-shaped, cup-shaped, or tubular structure (often simulating a calyx tube) bearing the perianth and stamens at or near its rim; it may be free from or united to the ovary.



HYPERACUITY
Psychophysical tasks involving judgements of relative position that are about ten times finer than the separation of bars at the grating acuity limit.



HYPERCOLUMN
A set of columns in the primary visual cortex (V1) that contains columns responsive to lines of all orientations from a particular region of space and for both eyes. (See also OCULAR DOMINANCE COLUMNS and ORIENTATION COLUMNS).



HYPERCOMPLEX CELLS
A third category of striate cells identified by Hubel and Wiesel that have since been classified as subsets of simple and complex cells. They posses inhibitory zones at one or both ends of oriented excitatory regions, thereby responding to bars of preferred orientation only if they are not too long. (See also COMPLEX CELLS , END-STOPPED CELL and END-INHIBITION).



HYPEROPIA
An eye is hyperopic when the far point is at a virtual point behind the eye. Generally the hyperopic eye is too short with respect to the refractive state of the standard eye (ie an emmetropic eye or eye requiring no optical correction) or because the optical power of the eye is too low relative to the length of the standard eye. The focus is correctly adjusted using a "plus" lens power or convex lens. Hyperopia is often referred to as "long-sightedness" or "far-sighted". (See also MYOPIA and EMMETROPIA).



HYPERTROPHY
Excessive growth due to increase in cell size.



HYPERVOLEMIA
Plethora of blood; abnormal increase in the volume of circulating blood.




HYPOGYNOUS
Inserted below the gynoecium, and not adherent; immediately below oogonium; the ovary thus said to be superior. n. hypogyny.



IAA
[See INDOLE-ACETIC ACID]



IBOTENIC ACID
Substance used in lesion studies. Destroys cell bodies of neurons but leave axons intact.




ICONIC MEMORY
Short-lived visual sensory memory which lasts about 500 msec. Disrupted by masking (i.e. by a bright light). Tied to anatomical coordinates.



IDIOBLASTS
Plant cells containing oil, gum, calcium, or other products, and appearing to help provide mechanical support.



IGNEOUS ROCK
a. Rock formed directly from cooled magma, such as granite, that has erupted from deeper in the earth's crust; b. Any rock solidified from molten or partly molten material.



IGNITABILITY
Anything that has a flash point of less than 140o F or which burns readily. Examples are paint wastes, certain degreasers and other solvents.



ILLUMINANCE
Amount of light falling onto an surface. (See also LUMINANCE).



ILLUSORY CONTOURS
Contours which can be perceived in the absence of any real lines or edges. (See also EHRENSTEIN ILLUSION).



IMBRICATE
Having parts overlapping each other like roof tiles.



IMMERSED
Growing under water.



IMPERFECT FLOWER
a flower containing stamen and pistil organs required for pollination but lacking sepals or petals or both of these organs.



IMPOUNDMENT
Any land area or formation that can hold liquid. An impoundment, which is open to the atmosphere, is used to treat, store, or dispose of waste, and include aeration tanks, holding ponds tanks, holding ponds, and lagoons.



IN-PLACE MANAGEMENT
A series of steps used as an alternative to lead-based paint removal.



IN SITU DENSITY
Mass per unit volume. The reciprocal of specific volume. In oceanography, the density of sea water is numerically equivalent to specific gravity and is a function of salinity, temperature, and pressure.



INCISED
With sharp angles between the lobes; having deeply cleft margins.



INCLUDED
Not projecting beyond an enclosing part.



INCRASSATE
Becoming thick or thicker, especially toward a tip or margin.



INCREMENTAL SHAFT ENCODER
A component of a tide gauge for converting length to a shaft angle on a rotating disk.



INDEHISCENT
Fruits which do not open to release seeds, but whole fruit is shed from the plant; not opening to release spores.



INDIAN SPRING LOW WATER
A datum originated by Professor G. H. Darwin when investigating the tides of India. It is an elevation depressed below mean sea level by an amount equal to the sum of the amplitudes of he harmonic constituents M2, S2, K1, and O1.



INDIAN TIDE PLANE
[See INDIAN SPRING LOW WATER]



INDIGENOUS
Native; originating or occurring naturally in the place specified.



INDOLE-ACETIC ACID
a natural growth hormone found in plants.



INEQUALITY
A systematic departure from the mean value of a tidal quantity.



INERT
A material that will not react chemically with other ingredients.



INERTIAL FLOW
A solution of the relative hydrodynamic equations of motion in which only the horizontal component of the Coriolis and centrifugal forces are balanced.



INFILTRATION
The downward entry of water into the soil.



INFLORESCENCE
A flower or putting forth blossoms; the mode of development and arrangement of flowers on an axis; a flowering branch.



INFLUENT STREAM
[See LOSING STREAM]



INFRUCTESCENCE
The inflorescence in a fruiting stage; collective fruits.



INGESTION
The intake of water or food particles by "swallowing" them, taking them into the body cavity or into a vacuole. Contrast with absorption.



INJECTION WELL
A well used for the emplacement of fluids into a subsurface stratum.



INNER NUCLEAR LAYER
(See RETINAL LAYERS).



INTEGRIN
Adhesive protein of the extracellular matrix in animals.



INTERBLOBS
Areas in V1 between blobs. Receive input from parvocellular layers in the LGN via V1 layer 4C Cells respond best to lines of a particular orientation, but are insensitive to direction of movement. Most lack color selectivity, but may response to color-contrast borders. Some cells are end-stopped responding to short but not long lies or edge stimuli. Projects to pale stripes of V2.



INTERCALATED ZONES
Areas of cells falling between the parvocellular and magnocellular layers.



INTERCELLULAR
Lying between cells, as intercellular space in plant tissue.



INTERCOSTAL
Between the ribs.



INTERFERENCE
The overall influence of one plant or groups of plants on another, and encompasses allelopathy or competition, or both of these processes.



INTERNAL TIDE
A tidal wave propagating along a sharp density discontinuity, such as a thermocline, or in an area of gradually changing (vertically) density.



INTERNODE
The portion of a stem between nodes.



INTEROCULAR MOTION DISPLAY
A motion display in which the motion stimulus in each eye of the observer is ambiguous, yet perception of coherent motion is possible if the subject combines motion information from both the eyes.



INTERSPECIFIC COMPETITION
Competition between species for nutrients, space, light, etc.



INTERTIDAL ZONE
The zone between the mean higher high water and mean lower low water lines



INTERVAL
[See LUNITIDAL INTERVAL and LUNICURRENT INTERVAL]



INTRACELLULAR
Being or occurring within a body cell or within the body cells.



INTRASPECIFIC COMPETITION
A type of competition whereby an individual plant competes with one or more members of the same species for nutrients, space, light, etc.



INTRINSIC IMAGES
A proposal put forward by Barrow and Tenebaum (1978) in which the visual system maintains several representations of the visual scene including lightness, illumination, depth etc. and the user can access each individual representation separate from the others.



INTRINSIC TERMINATORS
Those terminators that are due to the natural end of the object rather than to occlusion by another surface.



INTRUSIVE
Plutonic. Antonym of extrusive.



INTUBATE
To insert a tube in a part, especially the larynx.



INTUMESCENCE
A mechanism whereby fire-retardant paints protect the substrates to which they are applied.



INVERSE BAROMETER EFFECT
The inverse response of sea level to changes in atmospheric pressure.



INVOLUCEL
A secondary involucre, as the bracts subtending the secondary umbels in the Umbelliferae.



INVOLUCRE
A group of closely placed bracts that subtend or enclose an inflorescence.



INVOLUTE
Leaves having the edges rolled inwards at each side, toward the adaxial side.



INVOLUTION
A rolling inwards of leaves.



ION
An atom or small molecule which carries a positive or negative charge.



ISANOSTERE
An isopleth of either specific volume anomaly or thermosteric anomaly.



ISOBAR
An isopleth of pressure.



ISOBARIC SURFACE
A surface of constant or uniform pressure.



ISOHALINE
An isopleth of salinity. Constant or uniform in salinity.



ISOLUMINANT
Stimuli in which information based on luminance contrast is eliminated and only differences in wavelength are present.



ISOMORPHISTIC APPROACH
Belief that perceptual variations in the visual filed must be accounted for by analogous variations of neural activity. Roughly speaking, the neural distribution should look like the percept.



ISOPLETH
A line of constant or uniform value of a given quantity.



ISOPYCNIC
An isopleth of density. Constant or uniform in density.



ISOTHERM
An isopleth of temperature.



ISOTOPE
One of two or more variations of the same chemical element, differing in the number of neutrons not the number of protons.



ISOTROPIC
Any process or filter which is not directionally selective or biased. (As opposed to anisotropic).



JPEG
Joint photographic experts group. Defined an image-compression algorithm based on a linear transform called the discrete consine transform (DCT). The image is first block coded, each block transfomred using the DCT, the transform coefficient guantized, and then subjected to a lossless compression algorithm. Loses some information about high spacial frequencies and suffers from some block artifacts.



JULIAN CALENDAR
A calendar introduced by Julius Caesar in the year 45 B.C., and slightly modified by Augustus a few years later.



JULIAN DATE
Technique for the identification of successive days of the year when monthly notation is not desired.



KANIZSA SQUARE
Illusory change in brightness created by surrounding figures.



KAPPA
Name of Greek letter used as the symbol for a constituent phase lag or epoch when referred to the local equilibrium argument and frequently taken to mean the same as local epoch.



KAPPA PRIME
Name of Greek letter (with prime mark) used as the symbol for a constituent phase lag or epoch when the Greenwich equilibrium argument (G) has been modified to a particular time meridian.



KARYOGAMY
A process of fusion of the nuclei of two cells; the second step in syngamy.



KEEL
The folded edge or ridge of any structure.



Kell
[See KELL FACTOR]



KELL FACTOR
Used to quantify the loss of vertical resolution in a line-scan imaging system due to artifacts of sampling.



KELP FOREST
Marine ecosystem dominated by large kelps. These forests are restricted to cold and temperate waters, and are most common along the western coasts of continents. Kelp forests first appeared in the Miocene.



KERATOCONUS
Keratoconus (conical cornea) is an recessive inherited condition that manifests as a thinning of the corneal apex, or central area of the cornea. With the weakening of the tissue there is a bulging of the tissue which increases the myopia of the affected eye.



KINETIC DEPTH EFFECT
When a wire shape is rotated behind a screen on which the shadow falls, observers are able to recover the structure from the motion and see the dynamic shadow pattern as a solid shape in motion.



KLUEVER-BUCY SYNDROME
Seen in temporally lobectomized animals. They unnaturally tame, indiscriminately sexual and "psychially" blind. They can not recognize objects or learn to discriminate between them.



KNOT
A speed unit of 1 international nautical mile (1,852.0 meters or 6,076.115,49 international feet) per hour.



KOFFKA-BENUSSI RING ILLUSION
The addition of an intervening line can chance the perceived lightness of the two sides of a ring with uniform luminance.



LABIATE
Lipped, as in a calyx or corolla.



LACERATE
Said of a margin torn irregularly.



LACINIATE
Cut into narrow, jagged lobes or segments.



LACQUER
A fast-drying usually clear coating that is highly flammable and dries by solvent evaporation only.



LACUNATE
With air spaces or chambers in the midst of tissue.



LAGGING OF TIDE
The periodic retardation in the time of occurrence of high and low water due to changes in the relative positions of the Moon and Sun.



LAGOON
1. A shallow lake or pond, especially one connected with a larger body of water; 2. an area of shallow salt water separated from the sea by sand dunes; 3. the area of water surrounded by an atoll, or circular coral reef.



LAKE
An inland body of water, usually fresh water, formed by glaciers, river drainage, etc., larger than a pool or pond.



LAMBDA
Smaller lunar evectional constituent.



LAMELLATE
Made up of thin plates or lamina.



LAMINA
The expanded, blade part, of a foliar leaf, petal, etc.



LAMINARIN
A beta-glucan polysaccharide produced by many chromists through photosynthesis.



LANATE
Wooly, with long intertwined, curled hairs.



LANCEOLATE
1. Shaped like a lance; 2. broadest toward the base and narrowed to the apex, several times longer than wide.



LARVA
Among invertebrates, an immature stage in the life cycle which usually is much smaller than, and morphologically different from, the adult. In insects with metamorphosis, the larva must become a pupa before reaching adulthood.



LARYNGEAL
Pertinent to the larynx.



LATERAL GENICULATE NUCLEUS
Structure located in the thalamus which is a major recipient of axons from the retina. About 10% of its input is from the retina. It is composed of 6 layers. While input to the LGN from the two eyes is segregated, significant binocular influence can be exerted on the LGN by the cortex.



LATEX-BASED PAINT
General term used for water-based emulsion paints made with synthetic binders such as 100% acrylic, vinyl acrylic, terpolymer or styrene acrylic.



LATITUDE
The angular distance between a terrestrial position and the equator measured northward or southward from the equator along a meridian of longitude.



LAVA
Any molten material that is extrusive or volcanic, or the rock that forms from a molten extrusive.



LEACHING
The removal of dissolved chemicals from soil by the movement of a liquid (like water).



LEAD
A metal, previously used as a pigment in paints.



LEAF
A lateral outgrowth from a stem that constitutes part of the foliage of a plant and functions primarily in food manufacture by photosynthesis.



LEAF TRACE
The strand of vascular tissue which connects the leaf veins to the central vascular system of the stem.



LEAFLET
In a compound leaf, the individual blades are called leaflets.



LEAP YEAR
A calendar year containing 366 days.



LEFT VISUAL HEMIFIELD
The left half of the visual field, projects on the nasal hemiretina of the left eye and on the temporal hemiretina of he right eye.



LEGUME
1. A 1-locular fruit, usually dehiscent along two sutures, bearing seeds along the ventral suture; 2. a leguminous plant.



LEMMA
The lower (abaxial), and larger, of two membranous bracts enclosing the flower in grass.



LENTICEL
Corky spots on young bark, arising in relation to epidermal stomates.



LENTICULAR
Shaped like a double-convex lens.



Level
[Synchronized Swimming] The body's position in relation to the water surface, such as high, medium or low.



LEVEL OF NO MOTION
A level (or layer) at which it is assumed that an isobaric surface coincides with a geopotential surface.



LEVEL SURFACE
[See GEOPOTENTIAL SURFACE]



LGN
(See LATERAL GENICULATE NUCLEUS).



Lift
[Synchronized Swimming] When one or more swimmers gives support to lift another swimmer (or more) above the surface of the water.



LIGHTNESS
The perception of reflectance. Related to the perception of an object's surface.




LIGHTNESS CONSTANCY
Objects are perceived to maintain a relatively constant surface lightness despite changes in illumination (Type I) or background color (Type II).




LIGNIFY
1. To convert into wood or woody tissue; 2. to become wood or woody by chemical and physical changes in the cell walls that convert some or all of the constituents into lignin or lignocellulose.



LIGNIN
Organic substances which act as binders for the cellulose fibers in wood and certain plants, and adds strength and stiffness to the cell walls. Chemical structure of lignin is composed of a polymer of high carbon content but distinct from the carbonates. Consists of C6,C3 units.



LIGULATE
Having or pertaining to ligules.



LIGULE
Hyaline extension of the leaf sheath on the adaxial side of the leaf.



LIMB
The spreading part of a synsepalous calyx or sympetalous corolla, usually referring only to the calyx or corolla lobes, sometimes to their lips.



LIMESTONE
A carbonate sedimentary rock composed of more than 50 percent of the mineral calcium carbonate (CaCO3).



LIMNOLOGY
1. The study of river system ecology and life; 2. The scientific study of physical, chemical, meteorological, and biological conditions in fresh waters.



LINE MOTION ILLUSION
(See TRANSFORMATIONAL APPARENT MOTION).



LINEAR
Long and slender with parallel or nearly parallel sides.



LINESPREAD
The distribution of how the image of a very thin line is blurred on the retina (due to diffraction). Depends on pupil size.




LINKING HYPOTHESIS
Claim that a particular mapping occurs, or that a particular mapping principle applies between perceptual stages and stages of the visual substrate.




LINSEED OIL
Drying oil made from the flax seed and used as a solvent in many oil- based paints.



LIP
The upper or lower part of a bilabiate calyx or corolla.



LIPIDS
A class of biochemical compounds which includes fats, oils, and waxes.



LIQUID DRIERS
Solution of soluble driers in organic solvents.



LITHOPONE
A white pigment of barium sulfate and zinc sulfide.



LITTER
Leaf litter, or forest litter, is the detritus of fallen leaves and bark which accumulate in forests.



LITTORAL CURRENT
A current in the littoral zone such as a long shore or rip current.



LITTORAL ZONE
In coastal engineering, the area from the shoreline to just beyond the breaker zone. In biological oceanography, it is that part of the benthic division extending from the high water line out to a depth of about 200 meters.



LOBULATE
Divided into small lobes.



LOCAL EPOCH
[See KAPPA]



LOCAL TIME
Time in which noon is defined by the transit of the Sun over the local meridian as distinguished from standard time which is based upon the transit of the Sun over a standard meridian.



LOCULAR
Having the nature of, or consisting of cells.



LOCULE
A compartment of an anther or an ovary.



LOCULICIDAL
Dehiscent dorsally down middle of carpels.



LODICULE
A scale at base of an ovary in grasses, supposed to represent part of a perianth.



LOG LINE
A graduated line used to measure the speed of a vessel through the water or to measure the velocity of the current from a vessel at anchor.



LOMENT
A fruit of some legumes, contracted between the seeds, the 1-seeded segments separating at fruit maturity.



LONG-DAY PLANT
A plant that requires more than 12 hours of daylight before flowering will occur.



LONG PERIOD CONSTITUENT
A tidal or tidal current constituent with a period that is independent of the rotation of the Earth but which depends upon the orbital movement of the Moon or the Earth.



LONG-SIGHTEDNESS
(See HYPEROPIA).



LONG WAVES
[See LONG PERIOD WAVES]



LONGITUDE
Angular distance in a great circle of reference reckoned from an accepted origin to the projection of any point on that circle.



LONGSHORE CURRENT
A current paralleling the shore largely within the surf zone.



LOOP CURRENT
A current setting clockwise in the Gulf of Mexico.



LOOP OF STATIONARY WAVE
That portion of the oscillating area where the vertical movement is greatest.



LORICA
A vase-shaped or cup-shaped outer covering. Found in many protists, including some flagellates, ciliates,
chrysophytes, and choanoflagellates, as well as in some animal cells.



LOSING STREAM
A stream or portion of a stream that discharges water into the groundwater.



LOSSLESS COMPRESSION
An image compression method which preserves image information perfectly. For example, as nearby pizels in an image are usually similar (highly correlated), one can eliminate this redundency by coding one pixels intensity I(x,y), and subsequenct pixels by their difference (I(x,y+1)-I(x,y)) rather than the values themselves. The new representation has a lower correlation and requires less storage space despite preserving all informatio. The best possible lossless compression is one in which the values are completely decorrelated as correlation (the ability to predict one value from another) is a sign of redundancy.



LOSSY COMPRESSION
Image processing techniques which save much space but do lose some information about the contens of an image. (See also LOSSLESS COMPRESSION and PERCEPTUALLY LOSSLESS COMPRESSION).



LOW PERMEABILITY LAYERS
Soil, sediment or other geologic material that inhibit water movement.



LOW TIDE
[See LOW WATER]



LOW WATER
The minimum height reached by a falling tide.



LOW WATER EQUINOCTIAL SPRINGS
Low water springs near the times of the equinoxes.



LOW WATER LINE
The intersection of the land with the water surface at an elevation of low water.



LOWER HIGH WATER
The lowest of the high waters of any specified tidal day due to the declination Al effects of the Moon and Sun.



LOWER LOW WATER
The lowest of the low waters (or single low water) of any specified tidal day due to the declination Al effects of the Moon and Sun.



LUCIFERASE
Enzyme which activates luciferin to produce bioluminescence.



LUCIFERIN
Compound whose activated form emits light.



LUMINANCE
Amount of light coming off of a surface. Subjectively, the unit of brightness measured in candela per meter squared (cd/m2).



LUNAR CYCLE
An ambiguous expression which has been applied to various cycles associated with the Moon's motion.



LUNAR DAY
The time of the rotation of the Earth with respect to the Moon, or the interval between two successive upper transits of the Moon over the meridian of a place.



LUNAR INTERVAL
The difference in time between the transit of the Moon over the meridian of Greenwich and a local meridian.



LUNAR MONTH
[See SYNODICAL MONTH]



LUNAR NODES
The points where the plane of the Moon's orbit intersects the ecliptic.



LUNAR TIDE
That part of the tide on the Earth due solely to the Moon as distinguished from that part due to the Sun.



LUNAR TIME
Time based upon the rotation of the Earth relative to the Moon. See lunar day.



LUNATE
crescent-shaped.



LUNATION
Same as synodical month.



LUNICURRENT INTERVAL
The interval between the Moon's transit (upper or lower) over the local or Greenwich meridian and a specified phase of the tidal current following the transit.



LUNISOLAR TIDES
Harmonic tidal constituents K1, and K2, which are derived partly from the development of the lunar tide and partly from the solar tide, the constituent speeds being the same in both cases.



LUNITIDAL INTERVAL
The interval between the Moon's transit (upper or lower) over the local or Greenwich meridian and the following high or low water.



LYSOSOME
Eukaryotic organelle which carries digestive enzymes. The lyzosome fuses with a vacuolar membrane containing ingested particles, which are then acted upon by the enzymes.



M CELL
(See GANGLION CELL).



M CONES
Medium wavelength sensitive cones (green). Are most sensitive to a wavelength of approximately 531nm.



M1
Smaller lunar elliptic diurnal constituent.



M2
Principal lunar semidiurnal constituent.



M3
Lunar terdiurnal constituent.



MACH BANDS
Bright and dark lines that appear near the brighter and darker borders of a blurred edge between two uniform regions of different luminance. Luminance ramps which are too steep or too shallow do not create mach bands.



MACROPHYTE
A member of the macroscopic plant life especially of a body of water; large aquatic plant



MACROSCOPIC
Items large enough to be observed by the naked eye.



MACULA
A small spot or colored area.



MACULA LUTEA
The cone rich area of the human eye that contains the fovea



MAELSTROM
Famous whirlpool off the coast of Norway in the Lofoten Islands between Moskenesoy and Mosken.



MAFIC
Term used to describe the amount of dark-colored iron and magnesium minerals in an igneous rock. Complement of felsic.



MAGMA
Molten rock generated within the Earth.



Magnet school
District-operated government schools designed to "attract" a racially diverse student body from a variety of attendance areas.



MAGNETIC AZIMUTH
Azimuth reckoned from the magnetic north or magnetic south.



MAGNETIC DECLINATION
Same as variation.



MAGNETIC DIRECTION
Direction as indicated by a magnetic compass after correction for deviation but without correction for variation.



MAGNOCELLULAR LAYER
2 deep layers of the LGN. Large neurons, termination sight of parasol ganglion cells.




MAGNOCELLULAR PATHWAY
Pathway that begins with the parasol (magno) ganglion cells in the retina and terminates within the magnocellular layer of the LGN. Has a high contrast gain than Parvocellular Pathway. (See also PARVOCELLULAR PATHWAY and GANGLION CELL).



MAGNOLIID
Any member of the basal assemblage of flowering plants.



MALE
In organisms with separate sexes, the one which produces sperm.



Manner of presentation
[Synchronized Swimming] The total command of a swimmer's performance as she presents it to the audience.



MANNOXYLIC
Wood in which there is a great deal of parenchyma tissue among the xylem is called mannoxylic. Cycads and pteridosperms have mannoxylic wood.



MANTLE
That portion of the interior of the Earth that lies between the crust and the core.



MARCESCENT
Withering but remaining persistent.



MARIGRAM
A graphic record of the rise and fall of the water.



MARINE
Refers to the ocean.



MARINE BOUNDARY
The mean lower low water line (MLLWL) when used as a boundary.



MARINE PAINT
Coating specially designed for immersion in water and exposure to marine atmosphere.



MARSH
A tract of wet land principally inhabitated by emergent herbaceous vegetation.



MASCARET
French for tidal bore.



MASTIGONEME
Small hair-like filaments found on the "hairy" flagellum of the Chromista.



MATERIAL SAFETY DATA SHEET
Information sheet that lists any hazardous substance that comprises one percent or more of the product's total volume.



MEAN CURRENT HOUR
Same as current hour.



MEAN DIURNAL TIDE LEVEL
A tidal datum. The arithmetic mean of mean higher high water and mean lower low water.



MEAN HIGH WATER
A tidal datum. The average of all the high water heights observed over the National Tidal Datum Epoch.



MEAN HIGH WATER LINE
The line on a chart or map which represents the intersection of the land with the water surface at the elevation of mean high water. See shoreline.



MEAN HIGHER HIGH WATER
A tidal datum. The average of the higher high water height of each tidal day observed over the National Tidal Datum Epoch.



MEAN HIGHER HIGH WATER LINE
The line on a chart or map which represents the intersection of the land with the water surface at the elevation of mean higher high water.



MEAN LOW WATER
A tidal datum. The average of all the low water heights observed over the National Tidal Datum Epoch.



MEAN LOW WATER LINE
The line on a chart or map which represents the intersection of the land with the water surface at the elevation of mean low water.



MEAN LOW WATER SPRINGS
A tidal datum. Frequently abbreviated spring low water. The arithmetic mean of the low water heights occurring at the time of spring tides observed over the National Tidal Datum Epoch.



MEAN LOWER LOW WATER
A tidal datum. The average of the lower low water height of each tidal day observed over the National Tidal Datum Epoch.



MEAN LOWER LOW WATER LINE
The line on a chart or map which represents the intersection of the land with the water surface at the elevation of mean lower low water.



MEAN RANGE OF TIDE
The difference in height between mean high water and mean low water.



MEAN RISE
The height of mean high water above the elevation of chart datum.



MEAN RISE INTERVAL
The average interval between the transit of the Moon and the middle of the period of the rise of the tide.



MEAN RIVER LEVEL
A tidal datum. The average height of the surface of a tidal river at any point for all stages of the tide observed over the National Tidal Datum Epoch.



MEAN SEA LEVEL
A tidal datum. The arithmetic mean of hourly heights observed over the National Tidal Datum Epoch.



MEAN SUN
A fictitious sun which is assumed to move in the celestial equator at a uniform speed corresponding to the average angular speed of the real Sun in the ecliptic, the mean sun being alternately in advance and behind the real Sun.



MEAN TIDE LEVEL
Same as half-tide level.



MEAN TIME
Time based upon the hour angle of the mean sun as distinguished from apparent time which is based upon the position of the real Sun.



MEAN WATER LEVEL
A datum. The mean surface elevation as determined by averaging the heights of the water at equal intervals of time, usually hourly.



MEAN WATER LEVEL LINE
The line on a chart or map which represents the intersection of the land with the water surface at the elevation of mean water level.



MEGASPORE
In plants which are heterosporous, the larger kind of spore is called a megaspore; it usually germinates into a female (egg-producing) gametophyte.



MEIOSIS
A two-stage type of cell division in sexually reproducing organisms. In meiosis, a diploid cell divides to produce four haploid cells, each with half the original chromosome content. For this reason, meiosis is often called a "reduction division". In organisms with a diploid life cycles, the products of meiosis are usually called gametes. In organisms with an alternation of generations, the products of meiosis are caled spores.



MELANGE
A body of rocks consisting of large blocks (mappable size) of different rocks jumbled together with little continuity of contacts.



MELANIN
Black pigment in the pigment epithelium cells that absorbs light not captured by the retina preventing it from being reflected off the back of the eye.



MEMBRANE
Semi-fluid structure which bounds all cells, and partitions the interior of eukaryotic cells. It consists primarily of two lipid layers, with proteins "dissolved" in the lipids.



MEMBRANOUS
Having a thin, soft, pliable texture.



MEMBRANOUS DISCS
Located in outer segments of photoreceptors



MENINGITIS
Inflammation of the membranes of the spinal cord or brain.



MERICARP
One of the two carpels that resembles achenes and forms the schizocarp of an umbelliferous plant.



MERISTEM
Group of undifferentiated cells from which new tissues are produced. Most plants have apical meristems which give rise to the primary tissues of plants, and some have secondary meristems which add wood or bark.



MEROPHYTES
Group of cells which have all been produced from the same initial cell. Leaves and stems in particular are often built from specific patterns of merophytes.



MESIC
1. Conditioned by temperate moist climate; 2. neither xerix nor hydric; 3. pertaining to conditions of medium moisture supply.



MESOKARYOTIC
Nuclear condition unique to the dinoflagellates in which the chromosomes remain permanently condensed.



MESOPIC
Intensities of light under which both rods and cones operate. (See also Photopic and Scotopic).



METAMERIC STIMULI
Two stimuli which despite their physical differences are perceptually indistinguishable.



METAMORPHIC ROCK
Any rock derived from other rocks by chemical, mineralogical and structural changes resulting from pressure, temperature or shearing stress.



METAMORPHOSIS
A process of developmental change in insects whereby a larva reaches adulthood only after a radical change in morphology, often involving a pupa stage.



METEOROLOGICAL TIDES
Tidal constituents having their origin in the daily or seasonal variations in weather conditions which may occur with some degree of periodicity.



METHEMOGLOBINEMIA
Condition that limits the oxygen-carrying capacity of red blood cells.



METONIC CYCLE
A period of almost 19 years or 235 lunations. Devised by Meton, an Athenian astronomer who lived in the fifth century B.C., for the purpose of obtaining a period in which new and full Moon would recur on the same day of the year.



MICROPHYLL
A kind of leaf, specifically one which has a single, unbranched vein in it. Microphylls are only found in the lycophytes.



MICROPHYLLIDIOUS
Small, leaf-shaped.



MICROSPECTROPHOTOMETRY
A procedure that involves the passage of a narrow measuring beam through the outer segments of individual photoreceptors to measure absorbance spectra in excised retinas.



MICROSPORE
In plants which are heterosporous, the smaller kind of spore; it usually germinates into a male (sperm-producing) gametophyte.



MICROTUBULE ORGANIZING CENTER
Bundles of protein tubes which may be found at the base of a eukaryotic flagellum. In animals, they also function in creating the arrays of microtubules that pull the chromosomes apart during mitosis.



MICROTUBULES
Type of filament in eukaryotic cells composed of units of the protein tubulin. Among other functions, it is the primary structural component of the eukaryotic flagellum.



MICROVILLI
Thin fingerlike protrusions from the surface of a cell, often used to increase absorptive capacity or to trap food particles. The "collar" of choanoflagellates is actually composed of closely spaced microvilli.



MID-OCEANIC RIDGES
Elongated rises on the ocean floor where basalt periodically erupts, forming new oceanic crust; similar to continental rift zones.



MIDEXTREME TIDE
An elevation midway between extreme high water and extreme low water occurring in any locality.



MIDGET GANGLION CELL
Small cell bodies and small dendritic arborizations. Correspond physiologically to Parvo Ganglion Cells



MINERAL SPIRITS
Paint thinner. Solvent distilled from petroleum.



MIRE
Synonymous with any peat-accumulating wetland.



MITOCHONDRION
Complex organelle found in most eukaryotes; believed to be descended from free- living bacteria that established a symbiotic relationship with a primitive eukaryote. Mitochondria are the site of most of the energy production in most eukaryotes; they require oxygen to function. See: double membrane.



MITOSIS
The process of nuclear division in eukaryotes. It is one step in cytokinesis, or cellular division.



MIXED
(Current) Type of tidal current characterized by a conspicuous diunal inequality in the greater and lesser flood strengths and/or greater and lesser ebb strengths.
(Tide) Type of tide characterized by a conspicuous diurnal inequality in the higher high and lower high waters and/or higher low and lower low waters.



MODAL
Perceptually salient, having a real phenomenological presence. (As opposed to Amodal).



MODULATION TRANSFER FUNCTION
A plot of the ratio of image contrast to target contrast at different spacial frequencies



MONDRIAN STIMULUS
Consists of a Mosaic of rectangular shapes of (usually) black, grey and white.



MONILIFORM
Constricted laterally and appearing beadlike.



MONOCHROMAT
An individual with only one spectral channel (i.e. retina receptors have the same spectral sensitivity).



MONOCLINOUS
Having both stamens and pistils in the same flower.



MONOCOTYLEDONS
A class of angiosperms having an embryo with only one cotyledon, part of the flower usually in threes, leaves with parallel veins, and scattered vascular bundles.



MONOCULAR DEPTH CUES
Relative size, texture gradients, perspective, shadow, height of retina image, interposition, motion parallax.



MONOCULAR ZONE
The areas of the visual field from which light projects only to one of the eyes. (See also Binocular Zone).



MONOECIOUS
A plant having unisexual male and female flowers on the same individual; said of a plant having unisexual flowers.



MONOMER
Substance composed of low molecular weight molecules capable of reacting with like or unlike molecules to form a polymer.



MONOPTIC STIMULATION
When only one eye views an image (the other eye being closed or occluded).



MONOTYPIC
A plant of only one type.



MONSOON CURRENT
An Indian Ocean current setting in a generally eastward to southeastward direction off India and Ceylon. It replaces the North Equatorial Current, reversed by wind stress of the south-west monsoons, in August and September.



MONTH
The period of the revolution of the Moon around the Earth.



MOOR
[Chiefly British] An extensive area of open rolling infertile land consisting of sand, rock, or peat usually covered with heather, bracken, coarse grass and sphagnum moss; a boggy area of wasteland usually dominated by grasses and sedges growing in a thick layer of peat.



MORPHOLOGY
A branch of biology that deals with the form and structure of animals and plants, a study of the forms, relationships, metamorphoses, and phylogenetic development of organs apart from their functions.



MOTILE
Able to move oneself about, capable of self-locomotion.



MOTION CAPTURE
Occurs when features (such as random dot patterns) with no net motion of their own appear to move in sychrony with other salient moving features.



MOTION PARALLAX
Movement of the image of an object over the retina. The rate of movement depends upon the velocity of the object relative to the eye and its distance from the eye.



MOTOR FUSION
Changing the vergence of the two eyes so that images that fall on different points in the two retinas come to fall upon corresponding places in the central retinas. (As opposed to Sensory Fusion).



MOVEMENT AGNOSIA
A selective loss of motion perception without loss of any other perceptual capability. Occurs after bilateral damage in the cortex of MT or MST.



MSDS
[See MATERIAL SAFETY DATA SHEET]



MTOC
[See MICROTUBULE ORGANIZING CENTER]



MUCRO
A stiff or sharp point abruptly terminating an organ; a small awn.



MULLER-LYER ILLUSION
Two lines of equal length appear to unequal.



MULTICELLULAR
Any organism composed of many cells.



MULTIPAROUS
a. Having borne more than one child; b. Producing more than one child at birth.



MULTIPLE TIDE STAFF
A succession of tide staffs on a sloping shore so placed that the vertical graduations on the several staffs will form a continuous scale referred to the same datum.



MURICATE
Having a rough surface texture owing to small, sharp projections.



MUSCULOCUTANEOUS
a. Pertinent to the muscles and skin; b. Supplying or affecting the muscles and skin.



MYCORRHIZAE
Symbiotic association between a fungus and the roots or rhizoids of a plant.



MYOPIA
An eye is myopic when the "far point"; a point at which light from an object is focussed on the retina, is located at a finite distance in front of the eye. Myopia can be due to either an eye which is too long relative to the optical power of the eye (axial myopia), or because the optical power of the eye is too high relative to the length of the standard eye (refractive myopia). The focus is correctly adjusted with a "minus" power lens, or concave lens. Myopia is often referred to as "short-sightedness" or "near-sighted". (See also HYPEROPIA and EMMETROPIA).



N2
Larger lunar elliptic semi diurnal constituent.



NAPHTHA
A petroleum distillate used mostly by professionals (as opposed to do-it- yourself painters) for cleanup and to thin solvent-based coatings.



NASAL HEMIRETINA
That portion of the retina that lies medial to the fovea. (See TEMPORAL HEMIRETINA and FIGURE).



NATIONAL TIDAL DATUM EPOCH
The specific l9-year period adopted by the National Ocean Service as the official time segment over which tide observations are taken and reduced to obtain mean values (e.g., mean lower low water, etc.) for tidal datums.



NATURAL RESINS
Resins from trees, plants, fish and insects.



NATURALIZE
To adapt to an environment not native; of foreign origin, but established and reproducing as though native.



NAVIFACE
The interface between atmosphere and ocean; air-sea interface; sea surface. Adjective, navifacial.



NEAP RANGE
See neap tides.



NEAP TIDES
Tides of decreased range or tidal currents of decreased speed occurring semimonthly as the result of the Moon being in quadrature.



NEAR-SIGHTEDNESS
(See MYOPIA).



NECKER CUBE
A cube with ambiguous perspective.



NECTAR
The sweetish liquid in many flowers used by bees for the making of honey.



NECTARY
A part of a flower that secretes nectar. pl. nectaries



NEGATIVE PRIMING
The increased reaction time (or sometimes error rate) to a stimulus which has recently been ignored in preference to a target in a selection or decision task.



NEOMORPHOSIS
Regeneration in cases where the new part is unlike anything in the body.



NEON-COLOR SPREADING
A phenomenon in which the color certain stimuli seem to "leak" into surrounding areas. For example using a red cross and an Ehrenstein figure. When the solid red-cross is perceived in isolation it looks normal. When the Ehrenstein figure is viewed in isolation it generates an illusory contour. When the red cross is places in the Ehrenstein figure, the red color flows out of the cross and tends to fill the illusory figure.



NEOTENY
The retention of juvenile characteristics in the adult individual.



NEURAPRAXIA
Cessation in function of a peripheral nerve without degenerative changes occuring.



NEUROLYSIS
a. Stretching of a nerve to relieve tension; b. Loosening of adhesions surrounding a nerve; c. Disintegration or destruction of nerve tissue.



NEUROMA
Former term for any type of tumor composed of nerve cells.



NEURON DOCTRINE
The idea that nerve cells are independent biological units.



NEUROTMESIS
Nerve injury with complete loss of function of the nerve even though there is little apparent damage anatomically.



NEUROTOXIN
Poison which interferes with nerve function, usually by affecting the flow of ions through the cell membrane.



NEUTRAL FLOWER
Said of a sterile flower composed of a perianth without any sexual organs.



NEWBUILD
New vessel from bow to stern.



NICHE
The portion of the environment which a species occupies. A niche is defined in terms of the conditions under which an organism can survive, and may be affected by the presence of other competing organisms.



NITROGEN FIXATION
The conversion of gaseous nitrogen into a form usable by plants. Ususally by bacteria.



NOCTURNAL
Active only at night.



NODAL LINE
A line in an oscillating body of water along which there is a minimum or no rise and fall of the tide.



NODAL POINT
The no-tide point in an amphidromic region.



NODE
1. A knob or joint of a stem from which leaves, roots, shoots, or flowers may arise; 2. See LUNAR NODES.



NODE CYCLE
Period of approximately 18.61 Julian years required for the regression of the Moon's nodes to complete a circuit of 360° of longitude.



NODE FACTOR
A factor depending upon the longitude of the Moon's node which, when applied to the mean coefficient of a tidal constituent, will adapt the same to a particular year for which predictions are to be made.



NODICAL MONTH
Average period of the revolution of the Moon around the Earth with respect to the Moon's ascending node.



NODOSE
Nodular, knotty.



NOMENCLATURE
The making and giving distinguishing names to all groups of plants.



NON-ATTAINMENT AREA
A geographical area that does not meet an ambient air quality standard for the pollutant.



NON-POINT SOURCE POLLUTION
The source of surface or groundwater pollution originating from diffuse areas without well-defined sources.



NONCLASSICAL RECEPTIVE FIELD
Classical receptive fields are plotted by spots of light or moving stimuli. If a cell responds consistently to that stimulus then the location of that stimulus is said to be within the cells classical receptive field. Activity outside that area can influence a cell's response to the original stimulus.



NONHARMONIC CONSTANTS
Tidal constants such as lunitidal intervals, ranges, and inequalities which may be derived directly from high and low water observations without regard to the harmonic constituents of the tide.



Nonsectarian school
Schools without any particular religious affiliation.



NONVOLATILE
The portion of a coating left after the solvent evaporates; sometimes called the solids content.



NORMAL TIDE
A nontechnical term synonymous with tide; i.e., the rise and fall of the ocean due to the gravitational interactions of the Sun, Moon, and Earth alone.



NUCLEAR MEMBRANE
The double membrane which surrounds the eukaryotic nucleus. It has many pores in its surface which regulate the flow of large compounds into and out of the nucleus.



NUCLEIC ACID
Class of biochemical compounds which includes DNA and RNA. They are among the largest molecules known.



NUCLEOID
Region in prokaryotes where the DNA is concentrated. Unlike a nucleus, it is not bound by a membrane.



NUCLEOTIDE
Unit from which nucleic acids are constructed by polymerization. It contains a sugar, a phosphate group, and an organic base. ATP is a nucleotide.



NUCLEUS
Membrane-bound organelle which contains the DNA in the form of chromosomes. It is the site of DNA replication, and the site of RNA synthesis.



NUCLEUS OF THE OPTIC TRACT
Receives input from directionally sensitive cells in the retina. Lesions produce deficits in tracking of moving stimuli.



NULL SETS
Sets of stimuli which all lead to the same activation of the individual photoreceptor and are thus indiscriminable for that photoreceptor



NUT
1. A hard-shelled dry fruit or seed having a more or less distinct separatable rind or shell and interior kernel or meat; 2. a dry indehiscent one-seeded fruit with a woody pericarp developing from an inferior syncarpous ovary.



NUTLET
A small nut.



NUTRIENT
Any element or simple compound necessary for the health and survival of an organism. This includes air and water, as well as food.



NUTRIENT CYCLING
All the processes by which nutrients are transferred from one organism to another. For instance, the carbon cycle includes uptake of carbon dioxide by plants, ingestion by animals, and respiration and decay of the animal.



NYMPH
In aquatic insects, the larval stage.



NYQUIST LIMIT
The highest resolvable frequency that can be unambiguously registered by an array of neural elements. A system that encodes spatial patterns at a seires of uniformly spaced sample points, , can exactly represent sine or cosine gratings of all spacial frequencies up to the Nyquist frequency.



OBLANCEOLATE
Shaped like a lance point reversed, that is, having the tapering point next to the leafstalk.



OBLIQUE
Slanting; unequal-sided.



OBLIQUITY FACTOR
A factor in an expression for a constituent tide (or tidal current) involving the angle of the inclination of the Moon's orbit to the plane of the Earth's Equator.



OBLIQUITY OF THE ECLIPTIC
The angle which the ecliptic makes with the plane of the Earth's Equator.



OBLIQUITY OF THE MOON'S ORBIT
The angle which the Moon's orbit makes with the plane of the Earth's Equator.



OBLONG
Elliptical and from two to four times as long as broad.



OBOVATE
Inversely ovate; having the shape of the longitudinal section of an egg, with the broad end at the top, as some leaves.



OBOVOID
Inversely ovoid; roughly egg-shaped, with narrow end downwards; said of some fruits.



OBSOLETE
Rudimentary or not evident; applied to a structure that is almost suppressed; vestigial.



OBTUSE
With blunt or rounded end.



OCCLUSION
Strong monocular depth cue.



OCEAN
The great body of salt water that covers mores than two thirds of the surface of the earth; any of its five principal geographical divisions, the Atlantic, Pacific, Indian, Arctic, and Antartic.



OCEANIC CRUST
The Earth's crust which is formed at mid-oceanic ridges, typically 5 to 10 kilometers thick with a density of 3.0 grams per centimeter cubed.



OCEANIC TRENCH
Deep steep-sided depression in the ocean floor caused by the subduction of oceanic crust beneath either other oceanic crust or continental crust.



OCEANOGRAPHY
The science of all aspects of the oceans, in spite of its etymology. The term implies the interrelationships of the various marine sciences of which it is composed.



OCELLUS
Eye-Cup. A patch of light-sensitive receptor cells sunk into the skin present in some species.



OCREA
A tubelike covering around some stems, especially of plants of the Polygonaceae.



OCULAR DOMINANCE COLUMNS
The primary visual cortex (V1) is organized into alternating columns sensitive to input from the left and right eyes. (See also HYPERCOLUMN and ORIENTATION COLUMNS).



ODD-PINNATE
Said of compound leaves having an odd number of leaflets, this is usually easily determined because there is a single terminal leaflet.



OFF-CENTER CELLS
Decrease their activity when light increments are presented in their receptive fields. Surrounded by an antagonistic region which responds with the opposite polarity. Both ganglion and bipolar cells are separated into two classes, on-center and off-center. The off-center cells have dendrites that branch in the outer portion of the inner plexiform layer. (See also ON-CENTER CELLS).



OIL PAINT
A paint that contains drying oil, oil varnish or oil-modified resin as the film-forming ingredient.



OLEORESIN
A natural plant product that contains oil and resins.



OMNIVORE
Literally, an organism that will eat anything. Refers to animals who do not restrict their diet to just plants or other animals.



OMOHYOID
a. Concerning the scapula and the hyoid bone; b. Muscle attached to the hyoid bone and the scapula.




ON-CENTER CELLS
Increase their activity when light increments are presented in their receptive files. Surrounded by an antagonistic region which responds with the opposite polarity. Both ganglion and bipolar cells are separated into two classes, on-center and off-center. The on-center cells have dendrites that branch in the inner portion of the inner plexiform layer. (See also OFF-CENTER CELLS).



OPEN SEA DWELLING
Of marine biota that live suspended in the water.



OPPOSITE
1. Said of leaves or bracts occurring two at a node on opposite sides of the stem; 2. Said of flower parts when one part occurs in front of another.



OPSIN
Protein portion of rhodopsin.



OPTHALMOSCOPE
Device for seeing light reflected from the interior of the eye. First built by Hermann von Helmholtz.



OPTIC CHIASM
Location where the optic nerve axons from the two retinae join and are reorganized into two separate groups (the optic tracts) that encode information about the right and left visual fields.



OPTIC DISK
Where the ganglion cell axon fibers leave the retina. Contains no photoreceptors and therefore creates a blind spot in the visual field.



OPTIC NERVES
Myelinated axons from the optic disk of each eye which join at the optic chiasm.



OPTIC RADIATIONS
Projections from LGN to primary visual cortex (V1).



OPTIC TECTUM
Structure in the mid-brain of cold-blooded vertebrate that receives input from the optic nerve (homologous to the superior colliculi)



OPTIC TRACT
Retinal fibers leaving the optic chiasm separated by visual hemi-field (i.e. not by eye). Projects to three areas, the pretectum, the superior colliculus and the LGN.



OPTOKINETIC NYSTAGMUS
Eye movements characterized by a series of smooth movements in the same direction of a moving visual scence interspersed with rapid movements in the opposite direction. (See also OPTOKINETIC REFLEX).



OPTOKINETIC REFLEX
Elicited by coherent movement of a large region of the visual field. Helps stabilize the visual scene on the retina. (See OPTOKINETIC NYSTAGMUS).



OPTOMOTOR RESPONSE
The turning response of an animal presented with uniform flow of optic texture in the direction which minimizes rate of flow relative to the animal.



ORBICULAR
Round or shield-shaped with petiole attached to center.



ORGAN
Collection of tissues which performs a particular function or set of functions in an plant's body. The leaf, stem, and root are three organs found in many plants.



ORGANELLE
Membrane-bound structure in a eukaryotic cell. Organelles partition the cell into regions which carry out different cellular functions. Mitochondria, the ER, and lysosomes are examples of organelles.



ORGANIC
Generally refers to those substances produced by the metabolism of a living organism, especially carbon-containing compounds.



ORIENTATION COLUMNS
The primary visual cortex (V1) is organized into narrow columns (from pial surface to white matter) containing cells with almost identically the same orientation preferences.



ORIFICE
See STILLING WELL and PROTECTIVE WELL.



OUTCROP
Any place where bedrock is visible on the surface of the Earth.



OUTER SEGMENT
Portion of the photoreceptor cell that contains photopigment.



OVARY
The enlarged hollow part of a pistil in angiosperms in which ovules are formed.



OVATE
Having the shape of a longitudinal section of an egg; egg-shaped and attached by the broader end.



OVERFALLS
Breaking waves caused by the meeting of currents or by waves moving against the current.



OVERTIDE
A harmonic tidal (or tidal current) constituent with a speed that is an exact multiple of the speed of one of the fundamental constituents derived from the development of the tide-producing force.



OVIPAROUS
1. Egg-laying; 2. producing eggs which hatch after leaving the body of the female; 3. germinating while still attached to the parent plant; for example, mangrove.



OVOID
Egg-shaped.



OVULE
A structure in seed plants which contains the megasporangium (nucellus), megaspore (embryo sac), a food store, and a coat, and develops into a seed after fertilization.



OVUM
[See EGG]



OXIDATION
Chemical reaction upon exposure to oxygen.



OXIDIZING
[See AIR CURE]



OYASHIO
A current setting southwestward along the Siberian, Kamchatka, and Kuril Islands coasts in the Bering Sea and North Pacific Ocean.



PAINT
A coating including resin, a solvent, additives, pigments and, in some products, a diluent.



PAINT REMOVER
A chemical that softens old paint or varnish and permits it to be easily scraped off. Also called "stripper."



PAINT THINNER
[See MINERAL SPIRITS]



PALEA
The upper, and usually shorter and thinner, of two membranous bracts enclosing the flower in grasses.



PALEOHERB
Any member of a group of basal flowering herbs which may be the closest relatives of the monocots. They include the water lilies, Piperales, and Aristolochiales.



PALEOSOL
Soil horizon from the geologic past.



PALINOPSIA
(Literally 'seeing again') is a form of visual perseveration. It refers to reappearance of an image after some time when the original external stimulus is no longer available. Neural basis of palinopsia is unknown but many palinopsia patients have some right-hemisphere disturbances.



PALMATE
Leaves divided into lobes arising from a common center.



PANDEMONIUM
A feature based object recognition scheme. Feature demons signal the presence of features in an image. Cognitive demons look for feature combinations. Decision demon picks most active cognitive demons.



PANDURATE
Shaped somewhat like a violin, as some leaves.



PANICLE
A branched racemose inflorescence often applied more widely to any branched inflorescence.



PANICULATE
Panicled; arranged or growing in panicles.



PANUM'S FUSIONAL AREA
Region of space within which perception of a single object is possible. (See also STEREOPSIS).



PANUM'S LIMITING CASE
The minimum conditions for the perception of stereopsis consisting of three lines, one for one eye and two for the other.



PAPILLA
A glandular hair with one secreting cell above the epidermis level.



PAPILLOSE
Descriptive of a surface beset with short, blunt, rounded, or cylindric projections.



PARALLAX
The angle formed at the center of a celestial body between a line to the center of the Earth and a line tangent to the Earth's surface.



PARALLAX INEQUALITY
The variation in the range of tide or in the speed of a tidal current due to changes in the distance of the Moon from the Earth.



PARALLAX REDUCTION
A processing of observed high and low waters to obtain quantities depending upon changes in the distance of the Moon, such as perigean and apogean ranges.



PARALLEL PATHWAYS
Anatomical and physiological evidence exists for parallel pathways in the visual system e.g. Ventral and Dorsal streams for spatial and object processing. Parvo and Magno pathways from LGN to V2, V2 and V4. Hubel and Livingstone (1987) supported a few for strong segregation of the M and P pathways. Recent evidence (see Merrigan and Maunsell, 1994 for a review) strongly disputes this claim and the general viewpoint today is that much inter-stream communication occurs and that strict segregation of paths is unlikely.



PARALLEL PLATE INTAKE
Intake of a stilling or protective well with two parallel plates attached below.



PARASITE
Organism which lives on or within another organism, on which it feeds.



PARASOL GANGLION CELL
Large cell bodies, large dendritic arborization. Correspond physiologically to Magno Ganglion Cells.



PARENCHYMA
Plant tissue, generally soft and of thin-walled, relatively undifferentiated cells which may vary in structure and function.



PARIETAL
1. Pertinent to, or forming, the wall of a cavity; 2. Pertinent to the parietal bone; 3. When the placenta is attached to the wall of the ovary.



PART-PER-MILLION
A measure of concentration of a dissolved material in terms of a mass ratio (milligrams per kilogram, mg/kg).



PARTURITION
Act of giving birth to young.



PARVOCELLULAR LAYER
4 superficial layers of the LGN. Small neurons, termination sight of midget ganglion cells.




PARVOCELLULAR PATHWAY
Pathway that begins with the midget (parvo) ganglion cells in the retina and terminates within the parvocellular layer of the LGN. Conduction slower than that of Magnocellular Pathway.



PATHOGENIC
Organism which causes a disease within another organism.



Pattern
[Synchronized Swimming] A formation made by the spatial relationship between the members of a team.



PATTERN ADAPTATION
The perceived width and orientation of a grating pattern can be altered by first adapting to grating pattern of different frequencies and orientations. After adapting the contrast sensitivity to stimuli near the frequency or orientation of the adapting pattern is reduced. Suggests the existence of neurons tuned for frequency and orientation at are fatigued by the adapting pattern.



PEAT
1. A piece of turf cut for use as a fuel; 2. A mass of partially carbonized plant tissue formed by partial decomposition in water of various plants and esp. of mosses of the genus Sphagnum, widely found in many parts of the world, varying in consistency from a turf to a slime used as a fertilizer, as stable litter, as a fuel, and for making charcoal.



PECTINATE
Comb-like.



PEDESTALED MOTION STIMULUS
A compound stimulus consisting of a linear superposition of a drifting sine wave (motion) and a stationary sine wave (pedestal). Defeats feature tracking, meaning that if observers attempt to track peaks to discover motion they would not be able to perceive coherent motion as the peaks merely oscillate back and forth. (i.e. computing motion from peaks, valleys or zero-crossing fails). Subjects, however, are able to perceive the correct motion of the moving sine wave as long as the amplitude of the pedestal is not large compared to the amplitude of the motion.



PEDICEL
The stalk of a flower in an inflorescence.



PEDUNCLE
The stalk of a flower borne singly or the stalk of an inflorescence.



PELAGIC
a. Pelagic organisms swim through the ocean, and may rise to the surface, or sink to the bottom. They are not confined to live on the bottom as benthic organisms do; b. [see OPEN SEA DWELLING]



PELORUS
An instrument used on a vessel in connection with a current line and current pole to obtain the set of the current.



PELTATE
Shield-shaped, leaves that are shaped like a shield and attached to the stem at the center or by some point distinctly within the margin, and having the petiole inserted into the undersurface of the lamina not far from the center.



PENETRATING FINISH
A finish that sinks into the substrate, as opposed to settling on the surface.



PENICULLATE
Having the form of a pencil.



PEPTIDOGLYCAN
Carbohydrate polymer cross-linked by proteins. It is found in the cell wall of Gram positive bacteria, where it stains with the dye crystal-violet.



PERCEPTIVE FIELD
Area of the retina or visual space that when stimulated by a visual stimulus produces a change in behavioral response (for example in a monkey).



PERCEPTUAL CONSTANCY
The phenomenon that the perception of an object remains constant despite changes in the its size, lighting conditions and orientation.



PERCEPTUALLY LOSSLESS COMPRESSION
An image processing technique with loses some information about contents of the image, but the distortions produced by the loss aren't visible to the human image processing system.



PERCHED WATER TABLES
Occur when a low permeability material, located above the water table, blocks or intercepts the downward flow of water from the land surface.



PERENNATION
1. Survival of a plant for a number of years; 2. To live over from season to season.



PERENNIAL
A plant that grows for 3 or more years and usually flowers each year.



PERFECT FLOWER
A flower with both essential and accessory organs.



PERFOLIATE
Said of opposite or whorled leaves or bracts that are united into a collarlike structure around the stem that bears them.



PERFUSION
a. Passing of a fluid through spaces; b. The pouring of a fluid; c. Supplying an organ or tissue with nutrients and oxygen by injecting blood or a suitable fluid into an artery.



PERI-STIMULUS TIME HISTOGRAM
Plot of the average number of action potentials at each moment in time following a brief test flash.



PERIANTH
1. The outer whorl of floral leaves of a flower, when not clearly divided into calyx and corolla; 2. collectively, the calyx and corolla, or either one if one is absent.



PERICARP
The fruit wall which has developed from the ovary wall; sometimes used for any fruit covering.



PERIDININ
Carotenoid pigment found in dinoflagellates.



PERIGEAN TIDES
Tides of increased range or tidal currents of increased speed occurring monthly as the result of the Moon being in perigee.



PERIGEE
The point in the orbit of the Moon or man-made satellite nearest to the Earth.



PERIGYNIUM
Fruit investing utricle of the sedges, Carex.



PERIGYNOUS
1. Growing in a ring around the pistil, as the stamens; 2. having stamens, etc. growing in this way, said of a flower.



PERIHELION
The point in the orbit of the Earth (or other planet, etc.) nearest to the Sun.



PERIOD
Interval required for the completion of a recurring event, such as the revolution of a celestial body or the time between two consecutive like phases of the tide or tidal current.



PERIORBITAL
Surrounding the socket of the eye.



PERIPHYTON
Dense strands of algal growth that cover the water surface between the emergant aquatic plants. Spirogyra is commonly responsible for this growth.



PERISTOME
A set of cells or cell parts which surround the opening of a moss sporangium. In many mosses, they are sensitive to humidity, and will alter their shape to aid in spore dispersal.



PERMANENT CURRENT
A current that runs fairly continuously and is independent of tides and other temporary causes.



PERMEABILITY
The property of porous materials indicating the ease with which liquids or gases will be transmitted through a soil or other porous material.



PERSISTENT
Remaining attached after the normal function has been completed.



PETAL
Any of the component parts, or leaves, of a corolla; the unit of structure of the corolla.



PETALOID
Like a petal.



PETIOLATE
Growing on, or provided with, a petiole.



PETIOLE
The slender stalk or stem of a leaf, also called a leaf stalk.



PETROLEUM
Crude oil or any fraction of crude oil that is liquid at standard temperature and pressure (60° Fahrenheit and 14.7 pounds per square inch absolute).



pH
a numerical measure of the acidity or alkalinity of water. The pH scale ranges from 1 (acidic) to 14 (alkaline).



PHASE
(1) Any recurring aspect of a periodic phenomenon, such as new Moon, high water, flood strength, etc. (2) A particular instant of a periodic function expressed in angular measure and reckoned from the time of its maximum value, the entire period of the function being taken as 360°.



PHASE INEQUALITY
Variations in the tides or tidal currents due to changes in the phase of the Moon.



PHASE LAG
Angular retardation of the maximum of a constituent of the observed tide (or tidal current) behind the corresponding maximum of the same constituent of the theoretical equilibrium tide. [Same as EPOCH]



PHASE REDUCTION
A processing of observed high and low waters to obtain quantities depending upon the phase of the Moon, such as the spring and neap ranges of tide.



PHENOTYPE
1. The characters of an organism due to the interaction of genotype and environment, a group of individuals exhibiting the same phenotypic characters; 2. The detectable expression of the interaction of genotype and environment constituting the visible characters of an organism.



PHENOTYPIC
A set of characters arising from reaction to environmental stimulus.



PHERENIC NERVE
a. One arising in the cervical plexus entering the thorax and passing to the diaphragm; b. A motor nerve to the diaphragm with sensory fibers to the pericardium.



PHLOEM
The tissue involved in the transport of carbohydrates and food materials in a vascular plant, being composed of sieve elements, parenchyma cells and sometimes also of fibers and sclereids.



PHOSPHATE
An ion consisting of a phosphorus atom and four oxygen atoms. Among other things, it is used in the constuction of nucleic acids.



PHOTIC ZONE
Region of the ocean through which light penetrates; and the place where photosynthetic marine organisms live.



Photon Noise
The fact that a stream of photons is not steady but fluctuates in intensity around an average value



PHOTOPIC
Bright light conditions where only the cones are functional. (See also MESOPIC and SCOTOPIC).



PHOTORECEPTOR
Cells specialized for the transduction of light. (See also CONE and ROD).



Photoreceptor Mosaic
The spacial arrangement of photoreceptors in the retina.



PHOTOSYNTHESIS
Biochemical process in which light energy is absorbed by chlorophyll, and is used to fuel the building of sugar molecules.



Phototransduction
The transformation of incoming light to a neural impulse



PHYCOCYANIN
Blue, water-soluble pigment found in the cyanobacteria and the red algae.



PHYCOERYTHRIN
Red, water-soluble pigment found in the cyanobacteria and red algae.



PHYLLODE
A winged petiole with flattened surfaces placed laterally to the stem and functioning as a leaf.



PHYLLOTAXY
The arrangement of the leaves on the stem. The three common positions are alternate, opposite, and verticillate.



PHYLOGENY
The racial history or evolutionary development of any plant or animal species.



PHYTOMELANIN
A papery "sooty" black layer over the seed of plants in the Asparagales, which includes agaves, aloes, onions and hyacinths. It is an important character for defining the group.



PHYTOPLANKTON
Tiny, free-floating, photosynthetic organisms in aquatic systems. They include diatoms, desmids, and dinoflagellates.



PIGMENT
1. Any colorful compound, used by living things to absorb or block sunlight, and in sexual displays; 2. Insoluble, finely ground materials that give paint its properties of color and hide.



PIGMENT EPITHELIUM
Cells lining the back of the eye containing melanin which resynthesize photopigment for photoreceptors. (See also MELANIN).



PILEUS
Umbrella-shaped structure of mushrooms or toadstools.



PILLOW LAVA
Lava extruded beneath water characterised by pillow-type shapes.



PILOSE
Hairy; pubescence comprised of scattered long, slender, soft hairs.



PINNA
A leaflet or a primary division of a compound leaf. pl. pinnas or pinnae.



PINNATE
1. Divided in a feathery manner; 2. with lateral processes of a compound leaf, having leaflets on each side of an axis or midrib.



PINNATELY COMPOUND
Leaves which are divided up like a feather.



PINNULE
a secondary pinna, one of the ultimate divisions of a bipinnate or twice-pinnate leaf.



PISTIL
The unit of female function of a flower, may be comprised of a single carpel or two or more carpels united.



PISTILLATE
Said of a flower bearing a pistil or pistils but not stamens, may refer also to a plant having only pistillate flowers.



PITH
The soft, spongy tissue, consisting of cellular tissue, in the center of certain plant stems.



PITS
Thin regions of the cell wall in xylem conducting cells. Their structure is an important characteristic for recognizing different kinds of wood.



PLACENTA
The part of the ovary from which the ovules arise.



PLACENTATION
The manner in which the placenta is arranged in the ovary.



PLANKTON
Tiny, free-floating organisms of the ocean or other aquatic systems. They may be phytoplankton or zooplankton.



PLANO-CONVEX
Flat on one side and convex on the other.



PLANT
any of a kingdom (Plantae) of living beings typically lacking locomotive movement or obvious sensory organs, generally making its own food, possessing cell walls, and unlimited growth.



PLANTATION
An unusually large estate in a tropical or subtropical region that is generally cultivated by unskilled or semiskilled labor under central direction.



PLANTLET
A little plant.



PLASMA MEMBRANE
Outer membrane of a cell, sometimes called the cell membrane. The term plasma membrane is used more frequently when discussing prokaryotes.



PLASMID
Circular loop of DNA in prokaryotes. Eukaryotic DNA is organized into chromosomes.



PLASMODESMATA
Cytoplasmic connections between neighboring cells in plant tissues.



PLASMOGAMY
A process of fusion of the cytoplasm of two cells; the first step in syngamy.



PLATE
Rigid parts of the Earth's crust and part of the Earth's upper mantle that move and adjoin eachother along zones of seismic activity.



PLATYSPERMIC
Having seeds which are flattened and disc-like.



PLICATE
1. Folded into plaits, usually lengthwise; 2. Arranged in pleats, as a fan.



PLUMOSE
With hairlike branches, feathery.



PLUTONIC
Applies to igneous rocks formed beneath the surface of the Earth; typically with large crystals due to the slowness of cooling. Synonym of intrusive. Antonym of volcanic.



PNEUMOTHORAX
A collection of air or gas in the pleural cavity.



POACHING
The stealing of game or from private property or from a place where shooting, trapping or fishing rights are reserved. Until the twentieth century, most poaching was subsistence hunting or fishing to augment scanty diets.



POCOSIN
A bog that has formed in a shallow, undrained depression, the surrounding land being somewhat elevated, the vegetation predominantly evergreen shrubs or small trees.



POGGENDORF ILLUSION
Perception of colinearity can be distorted by an intervening figure.



POINT-OF-ENTRY TREATMENT
The treatment of all water entering a house, farmstead or other facility, regardless of its intended use.



POINT-OF-USE TREATMENT
Treatment of water at the point it is used.



POINT SOURCE
Any discernible, confined and discrete conveyance, including but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container, rolling stock, concentrated animal feeding operation, vessel or other floating craft from which pollutants are or may be discharged. This term does not include return flows from irrigated agriculture.



POINT SOURCE POLLUTION
The source of surface or groundwater pollution that originates from a well-defined source.



POINTSPREAD
A measure of optical blur produced by natural imperfections of the lens of the eye. The response to a point of light produces a certain amount of blur, the amount of this blurring is known as the pointspread.



POLES
(of optic flow field) The two points in the optic flow field surrounding an observer moving through the environment at which there is no flow of optic texture. One is the point toward which the observer is moving and the other is the point away from which the observer is moving.



POLLEN
The male or fertilizing element of seed plants, consisting of fine yellowish powder formed within the anther of the stamen.



POLLEN TUBE
In seed plants, the extension of the male gametophyte as it emerges from the pollen grain in search of the female gametophyte.



POLLINATOR
Animal which carries pollen from one seed plant to another, unwittingly aiding the plant in its reproduction. Common pollinators include insects, especially bees, butterflies, and moths, birds, and bats.



POLLINIA
A mass of fused pollen produced by many orchids.



POLLINIUM
A mass of coherent pollen characteristic of orchids and milkweeds.



POLLUTANT
1. Air contaminants that fall in the categories for criteria and non-criteria pollutants; 2. Any unwanted chemical or change in physical property that renders a water supply unfit for its intended use.



POLYGAMO-DIOECIOUS
Polygamous but chiefly dioecious.



POLYGAMO-MONOECIOUS
Polygamous but chiefly monoecious.



POLYGAMOUS
Having bisexual, pistillate, and staminate flowers on the same individual plant.



POLYMER
1. Substance, the molecules of which consist of one or more structural units repeated any number of times; 2. A large molecule constructed from many smaller identical units. These include proeins, nucleic acids, and starches.



POLYMERIZATION
1. The interlocking of molecules by chemical reaction to produce very large molecules; 2. The process of making plastics and plastic-based resins.



POLYMORPHIC
Having, assuming, or occurring in various forms, characters, or styles.



POLYPETALOUS
With many separate petals.



POLYVINYL CHLORIDE
A synthetic resin used in the binders of coatings.



POND
A body of standing water smaller than a lake, often artifically formed.



PONZO ILLUSION
When two horizontal rods of equal length are drawn over an upside down V the upper rod appears longer than the lower rod. (See also CORRIDOR ILLUSION).



POOL HYPOTHESIS
Hypothesis for the mechanism for stereopsis. Suggests the visual system contains three pools, one for crossed disparities, one for uncrossed disparities and one for non-zero disparities. A particular depth is signaled by the relative activity of crossed and uncrossed pools rather than by a sharply tuned neuron coding a particular depth.



Pool pattern
[Synchronized Swimming] The path a swimmer takes through the water.



POP-OUT
Target items in a visual search that have features which allow them to be detected quickly regarless of the number of distractors presents are said to "pop-out".



POPLITEAL
Concerning the posterior surface of the knee.



POROROCA
Brazilian for tidal bore.



POROSITY
The ratio of the volume of open spaces or voids to the total volume of a porous material.



POST STIMULUS TIME HISTOGRAM
A method for examining cell response to a particular stimulus. The time after stimulus onset is divided into a number of bins. The stimulus is then presented repeatedly and the count in each bin increased each time the cell fires during that time bin.



POSTERIOR
a. Toward the tear or caudal end;opposed to anterior; b. In man, toward the back; dorsal; c. Situated behind, coming after.



POSTERIOR PARIETAL CORTEX
Concerned with the perception of the spatial relations among objects.



POTABLE WATER SUPPLY
A source of water that can be used for human consumption.



PPM
[See PART-PER-MILLION]



PRECIPITATION
The process where water vapor condenses in the atmosphere to form water droplets that fall to the earth as rain, sleet, snow or hail.



PREDATOR
Organism which hunts and eats other organisms. This includes both carnivores, which eat animals, and herbivores, which eat plants.



PRELUNATE CORTEX
Area V4 in rhesus monkey brain.



PRESBYOPIA
The condition whereby the amplitude of accommodation, or ability to focus on objects at near distances, decreases with increasing age. It is corrected by a different prescription for reading, which is additive to the normal spectacle correction used for distance vision. Some recent research indicates that presbyopia may be caused by structural changes in the tendons and elastic fibres of the posterior ciliary body. The age related increase in fibrillar material could cause decreased compliance of the posterior insertion of the ciliary muscle.



PRESSURE SENSOR
A pressure transducer sensing device for water level measurement.



PRETECTAL AREA
Midbrain area just rostral to the superior colliculus. Receives input from the optic tract. Projects bilaterally to the preganglionic parasympathetic neurons of the accessory oculomotor nucleus. Mediates pupillary light reflexes.



PREY
Organism hunted and eaten by a predator.



PRICKLE
A sharp pointed emergence arising from the epidermis or bark of a plant.



PRIMARY PRODUCTION
The quantity of new organic matter created by photosynthesis.



PRIME MERIDIAN
The meridian of longitude which passes through the original site of the Royal Observatory in Greenwich, England and used as the origin of longitude.



PRIMER
First complete coat of paint of a painting system applied to a surface.



PRINCIPLE OF UNIVARIANCE
The absorbtion of a long wavelength (low frequency, low energy) quantum has the same effect on a receptor as the absorbtion of a short wavelength (high frequency, high energy) quantum. It is the probability of absorption that changes photoreceptor sensitivity.



PROCESS WASTEWATER
Any water which, during manufacturing or processing, comes into direct contact with or results from the production or use of any raw material, intermediate product, finished product, by-product or waste product.



PROCUMBENT
Trailing or lying flat but not rooting.



PRODUCER
Any organism which brings energy into an ecosystem from inorganic sources. Most plants and many protists are producers.



PRODUCTION
The weight of new organic material formed over a period of time, plus any losses during that time period.



PRODUCTIVITY
Amount of production over a given period of time. Expressed as a rate such as g/m2 per day, kg/ha per year, etc.



PROGRESSIVE WAVE
A wave that advances in distance along the sea surface or at some intermediate depth.



PROKARYOTIC
Literally "before the nucleus", the term applies to all bacteria and archaea. Prokaryotic cells have no internal membranes or cytoskeleton. Their DNA is circular, not linear.



PROLIFEROUS
Bearing supplementary structures such as buds or flowers, either in an abnormal manner or in a manner that is normal but from adventitious tissue.



PROM
Passive range of motion.



PROPAGULUM
A runner or sucker used in the asexual propagation of plants. pl. propagula or propagules.



PROPELLANT
The gas used to expel materials from aerosol containers.



PROPRIOCEPTIVE
Pertinent to prioprioception - the awareness of one's own posture, movement and changes in equilibrium and the knowledge of position, weight and resistance of objects in relation to the body.



Propulsion technique
[Synchronized Swimming] The way a swimmer uses her arms, legs or both to move through the water; a driving force.



PROSOPAGNOSIA
A loss of the ability to identify members of complex categories such as faces.



PROSTRATE
Growing on the ground, trailing.



PROTECTIVE WELL
A vertical pipe with a relatively large opening (intake) in the bottom. It is used with the air acoustic ranging sensor and electronic processing (filtering) technique to minimize the nonlinear characteristics of the stilling well.



PROTEIN
Class of biochemical compounds constructed from amino acids. Proteins may be structural, such as those that make up hair and cartilage, or they may be reactive, such as the enzymes.



PROTEINACEOUS
Describes any structure which is composed of protein.



PROTOGYNY
Development of the female organs before the appearance of the corresponding male products - thus inhibiting self-fertilization.



PROTOPLASM
All the contents of a cell, including the nucleus.



PROTOSTELE
Vascular tissue developed in a solid central bundle.



PSEUDOELATERS
Moisture-sensitive cells produced in the sporangium of hornworts.



PSEUDOLAMINA
The extended apical portion of a phyllode.



PSEUDOPODIA
Fingerlike extensions from an amoeboid cell; literally "false feet".



PSEUDOVIVIPARY
A condition where vegetative propagules replace some or all of the normal sexual flowers in the inflorescence.



PSTH
(See POST STIMULUS TIME HISTOGRAM).



PSYCHOPHYSICAL FUNCTION
A plot showing the variation in threshold (e.g. the dimmest light required for response) with some stimulus dimension (e.g. wavelength).



PTERIDOPHYTE
A major division of the plant kingdom, having clear alternation of generations with a dominant vascular sporophyte initially dependent upon the gametophyte which is very reduced.



PTERIDOSPERM
An extinct group of seed plants which bore fern-like leaves.



PUBERULENT
1. Covered with fine, short, and nearly imperceptable down; 2. Minutely pubescent, the hairs soft, straight, erect, but scarcely visible to the unaided eye.



PUBESCENT
1. A general term for hairiness; 2. Covered with soft hair or down.



PUNCTATE
1. Dotted; 2. With depressed dots scattered over the surface.



PUPA
In metamorphozing insects, a stage between the larva and adult during which the organism undergoes major
developmental changes.



PUSTULATE HAIR
Hair with an enlarged base.



PYCNOCLINE
A layer in which the density increases significantly (relative to the layers above and below) with depth.



PYCNOXYLIC
Wood in which there is little or no parenchyma tissue among the xylem is called pycnoxylic. Conifers and flowering plants have pycnoxylic wood.



PYRIFORM
Pear-shaped.



QUADRATURE MIRROR FILTERS
Used in image compression. A QMF pair splits an image into two orthogonal components. One filter defines a convolution kernal that blurs and reduces the image. The second filter, which is orthogonal to the first is used to create a representation of the error signal. The representation is more eficient than normal pyramidal schemes as the resulting reduced image and error signal are orthogonal. In continuous rather than discrete form, the convolution kernals are called orthogonal wavelets.



QUADRATURE OF MOON
Position of the Moon when its longitude differs by 90ø from the longitude of the Sun.



QUADRATURE PHASE PAIR FILTERS
Filtering in which two sets of filters are used e.g. Odd and Even Gabor filters, whose receptive field profiles are said to be in 'Quadrature Phase'.



RACE
A very rapid current through a comparatively narrow channel.



RACEME
Inflorescence having a common axis and stalked flowers in acropetel succession.



RACEMOSE
An inflorescence whose growing points continue to add to the inflorescence and in which there are no terminal flowers, and the branching is monopodial, as racemes, or spikes.



RACHILLA
The zigzag center upon which the florets are arranged in the spikelet of grasses or in some sedges.



RACHIS
The central prolongation of the stalk (peduncle), the axis through an inflorescence, or of a leaf stalk (petiole), the axis through a compound leaf.



RADIALLY
Arranged or having parts arranged like rays developing uniformly around a central axis.



RADIALLY SYMMETRICAL
Said of a flower or set of flower parts which can be cut through the center into equal and similar parts along two or more planes; actinomorphic.



RADIATIONAL TIDE
Periodic variations in sea level primarily related to meteorological changes such as the semidaily (solar) cycle in barometric pressure, daily (solar) land and sea breezes, and seasonal (annual) changes in temperature.



RADICLE
The end of a plant embryo which gives rise to the first root.



RADIO-CARBON DATING
Method for determining the age of an organic substance by measuring the amount of the carbon isotope, carbon-14, remaining in the substance; useful for determining ages in the range of 500 to 70,000 years.



RADIOACTIVE SOURCE
Material that emits radiation spontaneously or an apparatus that produces one or more forms of radiation.



RADIOSPERMIC
Having seeds which are round or ovoid.



RAMET
An individual member of a clone.



RANDOM-DOT KINEMATOGRAM
Comprised of successive frames of random texture in each of which there is no perceptive form. However, the dots in a central portion of each pattern are displace by a constant amount from one frame to the next while the background texture remains the same. The dots comprising the central region are seen to move as a whole revealing a boundary between a moving figure and a stationary surround.



RANDOM-DOT STEREOGRAM
A pair of images consisting of a uniform randomly generated texture of dots. No form is recognizable in the pair, but when fused, displacement of textural elements produces the perception of depth. Evidence against the use of monocular contours for stereopsis.



RANGE OF TIDE
The difference in height between consecutive high and low waters.



RBCL
A gene which is located in the chloroplast of photosynthetic organisms. It codes for the large subunit of the protein rubisco, and its sequence has been useful in plant phylogenies.



REACTIVITY
A substance that is unstable or undergoes rapid or violent chemical reaction with water or other materials.



RECEPTACLE
The more or less expanded apex of a floral axis which bears the floral parts.



RECEPTIVE FIELD
Area of the retina and visual space that when stimulated produces a change in the response rate of a neuron.



RECHARGE AREA
The area where water predominantly flows downward through the unsaturated formation (zone) to become groundwater.



RECTILINEAR CURRENT
Same as reversing current.



RED TIDE
The term applied to toxic algal blooms caused by several genera of dinoflagellates (Gymnodinium and Gonyaulax) which turn the sea red and are frequently associated with a deterioration in water quality.



REDUCER
[See DILUENT]



REDUCING AGENT
[See DILUENT]



REDUCING SOLVENT
[See DILUENT]



REDUCTION DIVISION
[See MEIOSIS]



REDUCTION FACTOR
Reciprocal of node factor (f).



REFERENCE DOSE
The maximum daily exposure to a chemical that is judged to be without risk of adverse systemic health effects over a person's lifetime. It formerly was called the ACCEPTABLE DAILY INTAKE.



REFLECTANCE
The fraction of incident light that is reflected toward the eye by an object.



REFLECTION DENSITOMETRY
Technique applied to the living eye to study photopigments. Measures the light reflected from the fundus (i.e. not absorbed by any pigments).



REMOTE
1. Separated from one another; 2. Separated by intervals or spaces greater than the ordinary.



RENIFORM
Having the form or shape of a kidney.



REPENT
Said of a stem that is prostrate and rooting at the nodes.



REPRODUCTION
Process by which new organisms are generated. Reproduction may be sexual, involving the fusion of gametes, or asexual.



Required elements
[Synchronized Swimming] Eight to ten fixed figures or other requirements which must be performed by all participants in a Technical Routine session.



RESIDUAL CURRENT
The observed current minus the astronomical tidal current.



RESIN
Synthetic or natural material used as the binder in coatings.



RETICULATE
Like network.



RETICULOPODIA
Long thread-like pseudopodia that branch apart and rejoin, forming a fine network. They are characteristic of forams.



RETINACULUM
The hook-like funicle of a seed of a plant of the family Acanthaceae; a band or band-like structure that holds an organ in place. pl. retinacula.



RETINAL
Light-absorbing portion of rhodopsin. The absorption of light causes retinal to change from 11-cis to 11-trans configuration



RETINEX THEORY
Theory of lightness and color perception. Argues that the color of an object is not determined by the composition of the light coming from the object. The color of a unit area is determined by a trio of numbers each computed on a single waveband to give the relationship for the waveband between the unit area and the rest of the unit areas in a visual scene.



RETINITIS PIGMENTOSA
A degeneration of the retinal pigment epithelium. This is a single celled layer of pigment cells that is between the retina and the choroid, the second "coat" of the eye. In this condition pigment granules are lost from the epithelium layer and deposited in clumps in the retina. Results in constricted visual fileds and eventraully reduced central vision and blindness. Effects primarity the rods.



RETINOTECTAL PATHWAY
Pathway from the retina to superior colliculi.



RETINOTOPIC MAP
A preservation of the spatial relationships of the photoreceptors in the retina in a higher brain representation.



RETRORSE
Having hairs or other processes turned toward the base.



RETUSE
With a shallow, rounded notch at the apex.



Reverse combined spin
[Synchronized Swimming] An ascending spin of at least 360 degrees followed without a pause by an equal descending spin in the same direction.



REVERSE OSMOSIS
Water treatment method used to remove dissolved inorganic chemicals and suspended particulate matter from a water supply. Water, under pressure, is forced through a semipermeable membrane that removes molecules larger than the pores of the membrane. Large molecules are flushed into waste waters. Smaller molecules are removed by an activated carbon filter.



REVERSING CURRENT
A tidal current which flows alternately in approximately opposite directions with a slack water at each reversal of direction.



REVETMENT
A protective structure usually consisting of sloping rocky walls.



REVOLUTE
Said of margins that are rolled backward (toward the abaxial side).



RHIZOID
Cellular outgrowth which usually aids in anchoring and to increase surface area for acquiring water or nutrients.



RHIZOMATOUS TUBER
Same as a corm.



RHIZOME
A subterranean horizontal root-like stem sending out leaves and shoots from its upper surface and roots from its lower surface.



RHODOPSIN
The visual pigment in rod cells. Contains opsin and retinal.



RHOMBUS
An outline like a rhomboid, a parallelogram with equal sides, having two oblique angles and two acute angles.



RHYOLITE
Highly felsic igneous volcanic rock, typically light in color; rough volcanic equivalent of granite.



RIBONUCLEIC ACID
The nucleic acid which carries the DNA message into parts of the cell where it is interpreted and used. The 18S ribosomal RNA sequence has been used in many groups of organisms to reconstruct phylogeny.



RIBOSOME
(ribosomal RNA)



RIFT ZONE
Elongate zones on continents that are in the form of a trough bounded by normal faults; the site of crustal extension, similar to that which occurs at mid-oceanic ridges.



RIGHT VISUAL HEMIFIELD
The right half of the visual field, projects on the nasal hemiretina of the right eye and on the temporal hemiretina of the left eye.



RIP
Agitation of water caused by the meeting of currents or by a rapid current setting over an irregular bottom.



RIP CURRENT
A narrow intense current setting seaward through the surf zone. It removes the excess water brought to the zone by the small net mass transport of waves.



RIPARIAN
Having to do with the edges of streams or rivers.



Risk factor
[Synchronized Swimming] The use of a difficult action in which an error in execution may cause a near disaster.



RIVER CURRENT
The gravity-induced seaward flow of fresh water originating from the drainage basin of a river.



RNA
[See RIBONUCLEIC ACID]



Rocket split
[Synchronized Swimming] A move involving a thrust to the vertical position, followed by a rapid leg split before returning to the vertical position at maximum height.



ROD
Photoreceptor for dim light conditions. Achromatic, lower acuity and temporal resolution than cones, outnumber cones 20 to 1. Rod system is convergent (many rods target one bipolar cell). (See also CONE).



ROM
Range of motion.



ROOT
The part of a plant, usually below the ground, that holds the plant in position, draws water and nutrients from the soil, stores food, and is typically non-green.



ROOT PRESSURE
Pressure in the roots which, when the shoot is cut off, will cause liquid to secrete from the root stump.



ROOT TUBER
Swollen food-storing roots.



ROOTLET
A radicel; a little root or small branch of a root.



ROOTSTOCK
Same as a rhizome.



ROSEATE
Rose-colored; rosy.



ROSETTE
A group of organs, such as leaves, clustered and crowned around a common point of attachment.



ROSIN
Natural resin obtained from living pine trees or from dead tree stumps and knots.



ROTARY CURRENT
A tidal current that flows continually with the direction of flow changing through all points of the compass during the tidal period.



ROTATE
1. Shaped like a wheel; 2. Radially spreading in one plane.



Routine
[Synchronized Swimming] A composition of strokes, figures and parts thereof, choreographed to music. It is judged on both technical merit and artistic impression.



RUBISCO
Protein which fixes carbon in photosynthetic organisms. It binds molecules of carbon dioxide to a five-carbon molcule. Rubisco is the most common protein on earth.



RUGOSE
1. Having or full of wrinkles; 2. corrugated; 3. ridged.



RUGULOSE
Same as rugose.



RUNCINATE
Pinnatified, with the lobes convex before and straight behind, pointing backward, like the teeth of a saw, as in the dandelion leaf.



RUNNER
A specialized stolon consisting of a prostrate stem rooting at the node and forming a new plant which eventually becomes detached from the parent plant as in a strawberry plant.



RUNOFF
Precipitation or irrigation water that does not infiltrate but flows over the land surface toward a surface drain, eventually making its way to a river, lake or an ocean.



S CONES
Short wavelength sensitive cones (blue). Are most sensitive to a wavelength of approximately 419nm.



SACCATE
Having the form of a sac; pouchlike.



SACK BEFORE FLOOD
The slack water immediately preceding the flood current.



SAGITTATE
Shaped like the head of an arrow with the basal lobes pointing downward.



SALINITY
1. A measure of the salt concentration of water. Higher salinity means more dissolved salts; 2. The total amount of solid material in grams contained in 1 kilogram of sea water when all the carbonate has been converted to oxide, the bromine and iodine replaced by chlorine, and all organic matter completely oxidized.



SALT MARSH
A salt marsh exists in protected coastlines in the middle to high latitudes. Plant and animals in these areas are adapted to salinity, periodic flooding, and extremes in temperature.



SALVERFORM
Said of a corolla in which the tube is essentially cylindrical, the lobes abruptly spreading; a gamopetalous corolla.



SANDSTONE
Sedimentary rock composed of sand-sized clasts.



SAPROPHYTE
Organism which feeds on dead and decaying organisms, allowing the nutrients to be recycled into the ecosystem. Fungi and bacteria are two groups with many important saprophytes.



SARMENTOSE
Producing slender prostrate branches or runners.



SAROS
A period of 223 synodic months corresponding approximately to 19 eclipse years or 18.03 Julian years, and is a cycle in which solar and lunar eclipses repeat themselves under approximately the same conditions.



SATURATED FORMATION ZONE
The portion of a soil profile or geologic formation where all voids, spaces or cracks are filled with water.



SATURATED THICKNESS (ZONE)
The total thickness of a saturated formation.




SATURATION
The richness of hue. Indicates how much a color has been diluted by grayness. (See also HUE).



SAXITOXIN
Neurotoxin found in a variety of dinoflagellates. If ingested, it may cause respiratory failure and cardiac arrest.



SCABRID
Slightly roughened.



SCABROUS
With small points or knobs, like a file; scaly, scabby, rough.



SCALENUS
One of three deeply situated muscles on each side of the neck extending from the tubercles of the transverse processes of the third through sixth cervical vertebrae to the first or second rib.



SCANDENT
Climbing plant of a creeping or scandent nature.



SCAPE
A stem growing from the crown of the root, bearing the blossom without leaves.



SCAPOSE
Scape-bearing; scapigerous; consisting of a scape.



SCARIOUS
Tough, thin, dry, and semitransparent.



SCHIZOCARP
A dry fruit, as in the maple, that splits at maturity into two or more one seeded carpels which remain closed.



SCISSION THEORY
A theory of Lightness perception forwarded by Metelli (1974) in which the visual system .



SCLERENCHYMA
Tissue of uniformly thick-walled, dead cells in the stem whose principal function is mechanical. The cells are usually grouped into fibers.



SCORPIOID
1. Resembling a scorpion; 2. Ssaid of a circinnately coiled determinate inflorescence in which the flowers are two-ranked and borne alternately at the right and left.



SCOTOPIC
Dim light conditions where only rods are functional.



Scull
[Synchronized Swimming] A movement of the hands designed to apply continuous pressure against the water to propel, balance and support the body.



SEA WALL
Solid vertical walls (either metal, concrete, or masonry) to protect shorelines or fill land. A seawall is a solid barricade built at the water's edge to protect the shore and to prevent inland flooding.



SEAWEED
Any large photosynthetic protist, including rhodophytes and kelps. Seaweeds are not true plants, but like plants they can make their own food.



SECOND-ORDER MOTION MECHANISMS
Capture motion information from moving properties such as a moving are of flicker in which there is no difference in mean luminance between target and background.



SECONDARY GROWTH
Growth in a plant which does not occur at the tips of the stems or roots. Secondary growth produces wood and bark in seed plants.



SECUND
Arranged or growing on one side only, as flowers or leaves on a stem.



SEDENTARY
Not moving. Many organisms, both plants and animals, spend the majority of their lives in one place.



SEDIMENT
Any solid material that has settled out of a state of suspension in liquid.



SEDIMENTARY ROCK
Any rock resulting from the consolidation of sediment.



SEED
1. The part of a flowering plant that contains the embryo and will develop into a new plant if sown; 2. A fertilized and mature ovule.



SEEPAGE
The movement of water into or through a porous material.



SEICHE
A stationary wave usually caused by strong winds and/or changes in barometric pressure.



SEISMIC SEA WAVE
Same as TSUNAMI.



SEMI-GLOSS FINISH
Finish that has a low luster sheen.



SEMIDIURNAL
Having a period or cycle of approximately one-half of a tidal day.



SENSITIVITY
a. The reciprocal of the minimum stimulus strength required for the stimulus to be detected reliably (1/threshold) May be related to noise and other mechanisms; b. Physiologically measured sensitivity averaged over many stimulus/response cycles. A measure of gain. Noise free.



SENSITIVITY CONTROL
Adjustment of eye sensitivity to compensate for a change in illumination.



SENSORY FUSION
The combining of drawing together of two images which fall on different points in the two retinas without changing the vergence of the two eyes. (As opposed to Motor Fusion).



SEPAL
Any of the leaf divisions of the calyx. When a calyx consists of but one part, it is said to be monosepalous; when of two parts, it is said to be disepalous; when of a variable and indefinite number of parts, it is said to be polysepalous; and when the parts are more or less united, it is said to be gamosepalous.



SEPTATE
Having or divided by a septum or septa.



SEPTICIDAL
1. Dividing through middle of ovary septa; 2. Dehiscing or breaking open at a natural dividing line.



SEPTUM
A partition separating two cavities or masses of tissue, as in fruits. pl. septa.



SEQUENCE OF CURRENT
The order of occurrence of the four tidal current strengths of a day, with special reference as to whether the greater flood immediately precedes or follows the greater ebb.



SEQUENCE OF TIDE
The order in which the four tides of a day occur, with special reference as to whether the higher high water immediately precedes or follows the lower low water.



SERRATE
1. Notched on edge like a saw; 2. Having sharp notches along the edge pointing toward the apex; as, a serrate leaf. When a serrate leaf has small serratures upon the large ones, it is said to be double serrate, as in the elm. A serrate-ciliate leaf is one having fine hairs, like eyelashes, on the serratures. A serrate-dentate leaf has the serratures toothed.



SERUM
a. Any serous fluid especially the fluid which moistens the surfaces of serous membranes; b. The watery portion of the blood after coagulation; a fluid found when clotted blood is left standing long enough for the clot to shrink.



SESSILE
1. Sitting directly on base without support, stalk, pedicel, or peduncle; 2. Attached or stationary as opposed to free living or motile.



SET
(of current) The direction towards which the current flows.



SETA
A bristle-like structure.



SETACEOUS
Bristly; set with bristles; consisting or having bristles.



SEXUAL REPRODUCTION
A type of reproduction in which two parents give rise to offspring that have unique combinations of genes inherited through the gametes of the two parents.



SHALLOW WATER CONSTITUENT
A short-period harmonic term introduced into the formula of tidal (or tidal current) constituents to take account of the change in the form of a tide wave resulting from shallow water conditions.



SHALLOW WATER WAVE
A wave is classified as a shallow water wave whenever the ratio of the depth (the vertical distance of the still water level from the bottom) to the wave length (the horizontal distance between crests) is less than 0.04.



SHEAR
A quasi-horizontal layer moving at a different velocity relative to the layer directly below and/or above.



SHEATH
1. A protective covering; 2. Lower part of leaf enveloping stem or culm.



SHELLAC
A coating made from purified lac dissolved in alcohol, often bleached white.



SHOCK CHLORINATION
The addition of chlorine for disinfecting a water supply system including the well, and all distribution pipelines.



SHOOT
A young branch which shoots out from the main stock.



SHORELINE
The intersection of the land with the water surface. The shoreline shown on charts represents the line of contact between the land and a selected water elevation.



SHORT-DAY PLANT
A plant requiring less than 12 hours of daylight in order for flowering to occur.



SHORT-SIGHTEDNESS
(See MYOPIA).



SHORT-TERM VISUAL STORE
Visual memory not affected by masking, not in anatomical coordinates, limited in capacity. Less is retained from complex images than simple images. (See also ICONIC MEMORY).



SIDEREAL DAY
The time of the rotation of the Earth with respect to the vernal equinox.



SIDEREAL MONTH
Average period of the revolution of the Moon around the Earth with respect to a fixed star.



SIDEREAL TIME
This is usually defined by astronomers as the hour angle of the vernal equinox.



SIDEREAL YEAR
Average period of the revolution of the Earth around the Sun with respect to a fixed star.



SIDERITE
Also called ironstone, that is a concretion of iron carbonate. Common in the Mazon Creek fossil beds.



SIGMA-T
An expression of density as a function of temperature and salinity (at atmospheric pressure) in a convenient numerical form.



SIGMA-ZERO
An expression of density as a function of salinity (at atmospheric pressure and 0øC) in a convenient numerical form.



SILENT SUBSTITUTION
If the action spectra of all photoreceptors types are known, spatial or temporal stimulus patterns can be designed which are invisible to some cone types while producing suprathreshold contrast for others. Thus one can study the range of psychophysical performance that is available for solely one type of cone signal. (See also NULL SETS).



SILICA
Amorphous silicon dioxide (glass). It is a structural component in many organisms, such as diatoms and horsetails.



SILICIFICATION
Process whereby silica replaces the original material of a substance. For example, silicified wood.



SILICONE
A resin used in the binders of coatings.



SILIQUE
The long, narrow pod of plants of the mustard family, Cruciferae, with valves which fall away from a frame bearing the seeds.



SIMPLE CELLS
One of three cell classifications for cells in the primary visual cortex (V1) proposed by Hubel & Wiesel. Simple cells show rectangular antagonistic on/off zones responding to bars of a particular orientations. They are described as a performing a linear filtering operation followed by a threshold nonlinearity. In a linear system the average response to a drifiting cosine grating will be a cosine at the same frequency. Because of the threshold, response to the negative half-cycles are suppressed.



SIMULTANEOUS CONTRAST
An object of moderate reflectance appears relatively brighter or darker according to whether spatially adjacent regions are considerably darker or brighter than the object itself.



SINGULAR VALUE DECOMPOSITION
A method for image compression. Defines a linear transformation from a set of image data to a new representation with statistically independent values that range over smaller values. Also know as the Karhunen-Love transform and the Hoteling transform.



SINUATE
Having a wavy margin, as some leaves.



SINUS
The rounded depression between two consecutive lobes. as of a leaf. pl. sinuses, sinus.



SIPHONOSTELE
Plant's vascular tissue developed as a central cylinder.



SIZE CONSTANCY
The fact that the perception of the sizes of objects remains remarkably constant at varying distance despite the fact that the image projected on the retina changes.



SLACK BEFORE EBB
The slack water immediately preceding the ebb current.



SLACK WATER
The state of a tidal current when its speed is near zero, especially the moment when a reversing current changes direction and its speed is zero.



SLOUGH
A wet place of deep mud or mire; a sluggish channel; a swamp, bog, or marsh, especially one that is part of an inlet or backwater.



SMALL DIURNAL RANGE
Difference in height between mean lower high water and mean higher low water.



SMALL TROPIC RANGE
Difference in height between tropic lower high water and tropic higher low water.



SNAKE
A deformable closed contour used in image analysis applications. Uses a elastodynamic model with applied forces for edge and curve detection. The energy of a stretchy, flexible contour (a snake) with tension and rigidity is minimized, while the snake itself is attracted to areas of darkness, brightness and/or intensity edges. Can be used to track objects over time as the potential function for the image changes from frame to frame.



SOIL
Unconsolidated materials above bedrock.



SOLAR DAY
The period of the rotation of the Earth with respect to the Sun. The mean solar day is the time of the rotation with respect to the mean Sun.



SOLAR TIDE
(1) The part of the tide that is due to the tide-producing force of the Sun. (2) The observed tide in areas where the solar tide is dominant.



SOLAR TIME
Time measured by the hour angle of the Sun. It is called apparent time when referred to the actual Sun and mean time when referred to the mean Sun.



Solicitation of Interest
A request from a prospective client for the expression of interest by construction professionals in participation in the client's project.



SOLID WASTE
Any discarded material that is abandoned, recycled or considered inherently waste-like.



SOLIDS
The part of the coating that remains on a surface after the vehicle has evaporated. The dried paint film.



SOLITARY WAVE
A wave of translation consisting of a single crest rising above the undisturbed water level without any accompanying trough.



SOLSTICES
The two points in the ecliptic where the Sun reaches its maximum and minimum declinations; also the times when the Sun reaches these points.



SOLSTITIAL TIDES
Tides occurring near the times of the solstices.



SOLVENT
Any liquid which can dissolve a resin.



SOURCE OF RADIATION
Material that emits radiation spontaneously or an apparatus that produces, or may produce when the associated controls are operated, one or more forms of radiation.



SOURCE REDUCTION
Steps taken to reduce waste generation and toxicity at the source through more effective utilization of raw materials and reformulation.



SPADIX
1. A racemose inflorescence with elongated axis, sessile flowers, and an enveloping spathe; 2. A succulent spike; a fleshy spike of flowers, usually enclosed in a spathe.



SPATHACEOUS
Having a spathe, or having the nature of a spathe.



SPATHE
A large leaflike part or pair of such enclosing a flower cluster (especially a spadix).



SPATULATE
Shaped like a spatula or spoon, gradually widening distally and with a rounded tip, as some leaves.



SPECIAL WASTES
This category includes sludges, bulky wastes, pesticide wastes, medical wastes, industrial wastes, liquid wastes, exempted hazardous wastes, friable asbestos wastes, combustion wastes and other solid wastes that are difficult or dangerous to manage.



SPECIALIST
Organism which has adopted a lifestyle specific to a particular set of conditions. Contrast with generalist.



SPECIES
A group of interbreeding individuals, not interbreeding with another such group, being a taxonomic unit including two names in binomial nomenclature, the generic name and specific epithet, similar and related species being grouped into a genus.



SPECIFIC CAPACITY
The productivity of a well. It is obtained by dividing the well discharge rate by the well drawdown while pumping.



SPECIFIC VOLUME
Volume per unit mass. The reciprocal of density (specific gravity).



SPECIFIC YIELD
The ratio of the volume of water that will drain from a unit volume of aquifer by gravity flow.



SPECTRAL EFFICIENCY
The relative luminous efficiency of light as a function of wavelength.



SPECULAR GLOSS
Mirror-like finish (usually 60 degrees on a 60-degree meter).



SPERMATOPHYTA
A major division of the plant kingdom, characterized by reproducing by seed and subdivided into the Gymnospermae and Angiospermae.



SPERMATOPHYTE
A seed plant.



SPICATE
Having the form of a spike.



SPICULE
1. A small, slender, sharp-pointed piece, usually on a surface; 2. A small spike of flowers.



SPIKE
A long flower cluster attached directly to the stalk.



SPIKELET
A small spike of a large one; a subdivision of a spike; as the spikelets of grasses.



Spin
[Synchronized Swimming] An ascending or descending rotation in a vertical position, performed in a uniform motion unless otherwise specified.



SPINE
A stiff sharp-pointed plant process as a modified leaf, leaf part, petiole, or stipule.



Split
[Synchronized Swimming] A position where the legs are split evenly forward and back, with the feet and thighs at the surface while the lower back is arched and the hips, shoulders and head are in a vertical line in the water.



SPONGIN
Proteinaceous compound of which the spicules in Demospongiae are composed.



SPORANGIOPHORE
A stalk to which sporangia are attached.



SPORANGIUM
A chamber inside of which spores are produced through meiosis.



SPORE
Any of various small reproductive bodies, often consisting of a single cell, produced by mosses, ferns, etc. asexually (asexual spore) or by the union of gametes (sexual spores); they are highly resistant and are capable of giving rise to a new adult individual, either immediately or after an interval of dormancy.



SPOROPHYLL
Any leaf which bears sporangia.



SPOROPHYTE
The diploid spore-producing phase in plants with alternation of generations.



SPRING
The point of natural groundwater discharge to a soil surface, river, or lake.



SPRING HIGH WATER
Same as mean high water springs.



SPRING LOW WATER
Same as mean low water springs.



SPRING TIDES
Tides of increased range or tidal currents of increased speed occurring semimonthly as the result of the Moon being new or full.



SPRINGER ILLUSION
A dot pattern produces the perception of faint diagonal lines.



SPUR
A slender, tubelike structure formed by an extension of one or more petals or sepals; also refers to a very short branch with closely spaced leaves.



STABILIZED RETINAL IMAGES
Technique for examining perception without eye movement accompanied by loss of color and contour perception. Demonstrates that movement of an image across the retina is vital for perception.



STALK
1. The stem or main axis of a plant, which supports the leaves, flowers, and fruit; 2. Any lengthened support on which an organ grows, as the petiole of a leaf or the peduncle of a flower.



STAMEN
The male reproductive organs in flowers; it is situated immediately within the petals, and is composed, in most cases, of two parts, the filament, and the anther, which is filled with pollen.



STAMINATE
1. Producing or consisting of stamens; 2. flowers with stamens but not pistils.



STAMINODIUM
A sterile stamen or an organ resembling one.



STAND OF TIDE
Sometimes called a platform tide. An interval at high or low water when there is no sensible change in the height of the tide.



STANDARD TIME
A kind of time based upon the transit of the Sun over a certain specified meridian, called the time meridian, and adopted for use over a considerable area.



STANDING CROP
Weight or organic material that can be sampled or harvested at any one time from a given area, but may not necessarily include the entire plant. Usually refers to normal harvesting procedures, unless specified, for the particular plant under consideration.



STANDING WAVE
A wave that oscillates without progressing.



STARCH
A complex polymer of glucose, used by plants and green algae to store surplus sugar for later use.



STATIC WATER LEVEL
The water level in a well located in an unconfined aquifer when the pump is not operating.



STATIONARY WAVE THEORY
An assumption that the basic tidal movement in the open ocean consists of a system of stationary wave oscillations, any progressive wave movement being of secondary importance except as the tide advances into tributary waters.



STELLATE
1. Starlike; 2. said of hairs that branch in such a manner as to radiate from a central point.



STEM
Main axis of a plant typically above the soil surface, having leaves or scales, and a characteristic arrangement of the vascular tissue.



STEM TUBER
Swollen structures produced by stolons and runners which remain dormant during adverse conditions and later grow into new plants when the conditions become favorable for growth.



STENCILS
Perforated sheets used with the tabulated hourly heights of the tide or speeds of the tidal current for the purpose of distributing and grouping them into constituent hours preliminary to summing for harmonic analysis.



STEREOGRATING
A random-dot stereogram creating the perception of a sinusion in depth. Can be used to obtain a measure of freqeuncy tuning (contrast sensitivity function) of stereopsis. Found to be about 10 times courser than frequency tuning for luminance.



STEREOPSIS
Perception of depth dependent upon disparity in the images projected on the retinas of the two eyes



STEREOSCOPE
Device for creating a 3-D image of a drawn objects. Works by projects two different images of the objects to the eyes.



STERIC ANOMALY
Same as specific volume anomaly.



STERNOCLEIDOMASTOID
One of two muscles arising from the sternum and inner part of the clavicle.



STIGMA
1. Dense region of pigments found in many photosynthetic protists which is sensitive to light, and thus functions somewhat like a miniature eye; 2. The upper tip or part of the pistil of a flower receiving the pollen. It is generally situated at the upper extremity of the style.



STILES-CRAWFORD EFFECT
Light entering the eye through the center of the pupil is more effective than light entering at a peripheral point near the edge of the pupil. This is largely to to the directionally sensitive photoreceptors which are oriented towrad the center of the pupil. This helps to minimize the effect of stray light.



STILLING WELL
A vertical pipe with a relatively small opening (intake) in the bottom. It is used in a gauge installation to dampen short period surface waves while freely admitting the tide, other long period waves, and sea level variations; which can then be measured by a tide gauge senor inside.



STIPE
The stalk-like basal part of an ovary, or of a fruit such as an achene; the stem bearing pileus in mushrooms and toadstools.



STIPEL
A small secondary stipule at the base of a leaflet.



STIPULE
One of two foliaceous or membranaceous processes developed at base of a leaf petiole, sometimes in tendril or spine form, sometimes fused.



STIPULES
Paired appendages found at the base of the leaves of many flowering plants.



STOLON
A stem which grows from a stem above the ground, taking root at the tip, and ultimately developing a new plant.



STOMA
One of the minute openings in the epidermis of leaves, stems, and other plant organs through which gaseous interchange between the atmosphere and the intercellular spaces within these structures occur; the opening together with its associated guard cells and accessory cells. pl. stomata.



STORM SURGE
The local change in the elevation of the ocean along a shore due to a storm.



STORM TIDE
The sum of the storm surge and astronomic tide.



STRABISMUS
A squint or strabismus is a failure of the two eyes to look at the same object thereby preventing binocular vision. Human binocular vision develops during the first few years of life. Interruption to the motor, sensory or central components, for example nerve or muscle defect, can lead to sensory or central defect. Causes of many squints are not fully understood although the majority are either a hereditary factor or a responsible defect.



STRAMINEUS
Of or like straw; straw-colored.



STRATUM
A layer of sedimentary rock; plural is strata.



STRAY LINE
Ungraduated portion of line connected with the current pole used in taking current observations.



STRENGTH OF CURRENT
Phase of tidal current in which the speed is a maximum; also the speed at this time.



STRENGTH OF EBB
Same as EBB STRENGTH.



STRENGTH OF FLOOD
Same as FLOOD STRENGTH.



STREPTOPHYTES
The clade consisting of the plants plus their closest relatives, the charophytes.



STRIATED
Marked by narrow lines or grooves, usually parallel.



STRIDOR
Harsh sound during respiration, high pitched and resembling the blowing of wind due to obstruction of air passages.



STRIGOSE
Covered with stiff hairs; ridged; marked by small furrows; surface clothed with stiff, often appressed hairs, these usually pointing in one direction.



STRIKE
The direction or trend of a bedding plane or fault, as it intersects the horizontal.



STRIPPER
[See PAINT REMOVER]



STROBILUS
A tightly clustered group of sporophylls arranged on a central stalk; commonly termed a "cone" or "flower".



STROOP EFFECT
When subjects are asked to name the colors of the ink in which the words are printed, their performance is considerably slowed if the words themselves are the names of other colors.



STRUCTURAL DESCRIPTION
A representational format for human pattern and object recognition consisting of a set of propositions about a particular configuration of features.



STYLE
Slender upper part of pistil, supporting stigma.



STYLOPODIUM
The fleshy support at the base of the style in flowers of the carrot family, Umbelliferae.



SUBDUCTION
The process of one plate descending beneath another.



SUBMERGE
To sink or plunge beneath the surface of water.



SUBMERGED LANDS
Lands covered by water at any stage of the tide.



SUBMERSED PLANTS
Plants growing with their root, stems, and leaves completely under the surface of the water.



SUBORBICULAR
Approximately circular.



SUBSTRATE
1. "Supporting surface" on which an organism grows. The substrate may simply provide structural support, or may provide water and nutrients. A substrate may be inorganic, such as rock or soil, or it may be organic, such as wood; 2. Any surface to which a coating is applied.



SUBULATE
Awl-shaped; slender and tapering gradually to a fine point.



SUCCESSIVE COLOR CONTRAST
Changes in the appearance of color occur as a result of preceding stimulation.



SUCCESSIVE CONTRAST EFFECT
The surface of a given luminance can appear darker or lighter depending on if the preceeding luminance was lower or higher.



SUCCULENT
Juicy; full of juice or sap.



SUFFRUTICULOSE
Moderately frutescent; obscurely shrubby; usually woody only basally.



SUGAR
Any of several small carbohydrates, such as glucose, which are "sweet" to the taste.



SULCATE
Furrowed, grooved; scored with deep, parallel furrows or grooves.



SUMMER TIME
British name for daylight saving time.



SUPERIOR COLLICULUS
A nucleus in the midbrain that coordinate visual, somatic and auditory information adjusting movements of the head and eyes towards a stimulus. contains four types of maps, a visual map, a map of the body surface, a map for sound in space and a motor map. Receives inputs from the retina (via the optic tract), the visual cortex, the somatosensory system and auditory systems. Mediates saccadic eye movements. Is the source of two major descending tracts, the tectospinal tract and the tectopontine tract in addition to regions of the brain stem controlling eye movements.



SUPINE
a. Lying on the back or with the face upward; b. Noting position of the hand or foot with the palm or foot facing upward; c. Opposite of prone.



SUPRASCAPULAR
Located above the scapula-the large flat triangular bone which forms the posterior part of the shoulder.



SURFACE MINING
All or any part of the process followed in the production of minerals from a natural mineral deposit by the open pit or open cut method.



SUTURE
1. A seam formed when two parts unite; 2. a seam or line or groove; usually applied to the line along which a fruit dehisces; 3. any lengthwise groove that forms a junction between two parts.



SWALE
A hollow or depression, especially one in wet, marshy ground.



SWAMP
Spongy land; low ground filled with water; a wooded area having surface water much of the time.



SYMBIOSIS
Literally, "living together". Many cases of symbiosis are mutual, in which both organisms rely on each other for survival. Other types of symbiosis include parasitism, in which one organism benefits at its host's expense, and commensalisms, in which one partner benefits and the other is neither benefited nor harmed.



SYMPHYSIOTOMY
Cutting a section of the symphysis pubia to facilitate childbirth by enlarging the pelvic outlet.



SYMPODIAL
Branching, growth of axillary shoots when apical budding has ceased.



SYNANGIUM
A cluster of sporangia which have become fused in development.



SYNCARP
A multiple or aggregate fruit derived from numerous separate ovaries of a single flower; a collective unit, as a blackberry.



SYNCLINE
A fold of rock layers that is convex downwards. Antonym of anticline.



SYNGAMY
The process of union of two gametes; sometimes called fertilization. It encompasses both plasmogamy and karyogamy.



SYNODICAL MONTH
The average period of the revolution of the Moon around the Earth with respect to the Sun, or the average interval between corresponding phases of the Moon.



SYNTEPALOUS
Flowers in which the tepals are fused.



SYZYGY
Position of the Moon when it is new or full.



TABLE ILLUSION
Although the parallelograms making up the top of the two coffee tables are exactly the same size (try checking with a cut out piece of paper) they look different presumably due to our experience with perspective.



TACHYCARDIA
Abnormal rapidity of heart action, usually defined as a heart rate over 100 per minute.



TACHYPNEA
Abnormal rapidity of respiration.



TACTILE
Perceptible to the touch.



TAENIA
Formation of ribbon-like structure with little or no differentiation between the leaf blade and stem.



TANNINS
Complex aromatic compounds some of which are glucosides, possibly giving protection or concerned with pigment formation.



TAPETUM
Silvery lining behind the retina in some animals active in dim light. Reflects light back through the eye and allows the photoreceptors a second chance to absorb photons.



TAPHONOMY
The study of what happens to a fossil, from the time of its initial creation (e.g. the death of an organism or the imprint left by the movement of an organism) and the time that the fossil is discovered by a paleontologist. For example, shells or bones can be moved my running water, and later be compressed by overlying sediment. Taphonomy is often broken into two parts, biostratinomy and the study of diagenesis.



TAXON
A taxonomic category or unit, as a species or genus.



TAXONOMY
1. A science that includes identification, nomenclature, and classification of objects, and is usually restricted to objects of biological origin; 2. orderly classification of plants according to their presumed natural relationships forming a basic biological discipline involving during its Linnean period the firm establishment of binomial nomenclature and acceptance of the static concept of fixity of the species, during its Darwinion period the dynamic concept of speciation by natural selection, and during its modern Mendelian epoch an expansion to include study of the mechanisms underlying speciation and related processes.



Technical merit
[Synchronized Swimming] The level of excellence demonstrated by the swimmers' mastery of highly specialised skills.



Technical merit score
[Synchronized Swimming] The score given by each judge in panel one for execution, synchronisation and difficulty.



Technical routine
[Synchronized Swimming] A routine which contains required elements woven into the choreography. Competitors are free to choose the music they perform to.



TECTOPONTINE TRACT
Relays information from the colliculus to the cerebellum for further coordination of eye and head movement.



TECTOSPINAL TRACT
Axons from the colliculus to the upper spinal cord where the neck motor neurons are located. Involved in reflex control of head and neck movements.



TELEMETRY
The capability of transmitting or retrieving data over long distance communication links, such as satellite or telephone.



TEMPERATE
Region in which the climate undergoes seasonal change in temperature and moisture. Temperate regions of the earth lie primarily between 30 and 60 degrees latitude in both hemispheres.



TEMPLATE MATCHING
An object recognition method. Incoming patterns are matched against a set of templates. If there is sufficient overlap between object and template, a match is signaled. Of limited use, primarily in alphanumeric character recognition.



TEMPORAL HEMIRETINA
That portion of the retina that lies lateral to the fovea.



TENDRIL
A slender twining or clasping process, modified stem, leaf, or part of a leaf, by which some plants climb.



TEPAL
Denoting a unit of the perianth when the sepals and petals are essentially alike and not readily differentiated.



TERDIURNAL
Having three periods in a constituent day.



TERETE
Nearly cylindrical in cross-section, as stems.



TERMINATORS
In the context of motion, terminators are those portions of a moving object which signal unambiguous motion. For a barber pole pattern these would be the line ends of the grating, for a translating diamond, these would be the corners.



TERNATE
Growing in groups of threes, as some leaves.



TERRESTRIAL
Living on land, as opposed to marine or aquatic.



TEST
Hard shell of certain unicellular protists.



TESTA
The hard outer covering or integument of seed.



TETRACHROMATIC COLOR VISION
Color vision based on four cone photoreceptor pigments in the retina. The fourth cone type is sensitive to U.V. light and seen in goldfish.



TEXTON
The basic textural elements of pre-attentive vision such as elongated blobs or line segments and their terminators which are important for segregation of textures



THALLOID
Of or resembling a thallus.



THALLOPHYTA
A primary division of plants including all forms consisting of one cell and cell aggregates not clearly differentiated into root, stem, and leaf, including bacteria, algae, fungi, and lichens.



THALLUS
A plant body that lacks differentiation into distinct forms of stems, leaves, roots, and does not grow from an apical point.



THECA
General term for any stiff outer covering of a unicellular protist, and usually made up of interlocking plates.
dinoflagellates and diatoms are examples of protists with thecae.



THERMOCLINE
A layer in which the temperature decreases significantly (relative to the layers above and below) with depth.



THERMOSTERIC ANOMALY
The specific volume anomaly (steric anomaly) that would be attained if the water were changed isothermally to a standard pressure of one atmosphere.



THEROPHYTES
An annual plant that overwinters as a seed.



THINNER
[See DILUENT]



THORN
A sharp rigid process on a plant; specif., a short, indurated, sharp-pointed, and leafless branch developed from a bud in a manner typical to a leafy branch.



THREATENED SPECIES
A threatened species is one that is likely to become endangered in the foreseeable future.



THROAT
Term applied to an expanded part of a corolla tube just below the lobes.



Thrust
[Synchronized Swimming] A move that starts from a back pike position with the legs perpendicular to the surface and involves a rapid vertical upward movement of the legs and hips as the body unrolls to assume the vertical position.



THYRSEUS
A panicle-like inflorescence consisting of a slender indeterminate main axis with lateral axes determinate, i.e., cymose.



TIDAL BORE
A tidal wave that propagates up a relatively shallow and sloping estuary or river in a solitary wave form.



TIDAL CURRENT
A horizontal movement of the water caused by gravitational interactions between the Sun, Moon, and Earth.



TIDAL CURRENT CHARTS
Charts on which tidal current data are depicted.



TIDAL CURRENTS
[See APOGEAN TIDES, NEAP TIDES, PERIGEAN TIDES]



TIDAL DAY
Same as LUNAR DAY.



TIDAL DIFFERENCE
Difference in time or height between a high or low water at a subordinate station and a reference station for which predictions are given in the Tide Tables.



TIDAL STREAM
British equivalent of United States tidal current.



TIDAL WAVE
A shallow water wave caused by the gravitational interactions between the Sun, Moon, and Earth. Essentially, high water is the crest of a tidal wave and low water, the trough.



TIDE
The periodic rise and fall of the water resulting from gravitational interactions between Sun, Moon, and Earth.



TIDE-PRODUCING FORCE
That part of the gravitational attraction of the Moon and Sun which is effective in producing the tides on the Earth.



TIDE STAFF
A tide gauge consisting of a vertical graduated staff from which the height of the tide can be read directly



TIDELANDS
The zone between the mean high water and mean low water lines. It is identical with intertidal zone (technical definition) when the type of tide is semi diurnal or diurnal.



TIDEWATER
Water activated by the tide generating forces and/or water affected by the resulting tide, especially in coastal and estuarine areas.



TIDEWAY
A channel through which a tidal current flows.



TILLER
Sprout, stalk, especially one from the base of a plant or from the axils of its lower leaves.



TIME MERIDIAN
A meridian used as a reference for time.



TISSUE CULTURE
The use of specialized methods to mass produce plants starting with small amounts of plant tissue.



TITANIUM DIOXIDE
White pigment in virtually all white paints. Prime hiding pigment in most paints.



TOMENTOSE
densely covered with short, matted hair.



TOTAL CURRENT
The combination of the tidal and non tidal current. The United States equivalent of the British flow.



TOTAL DISSOLVED SOLIDS
Water quality parameter defining the concentration of dissolved organic and inorganic chemicals in water.



TOXIC
Wastes are toxic if an extract from the waste is tested and found to exceed specific concentrations of heavy metals (such as mercury, cadmium or lead) or pesticides that could be released into ground water.



TRACHEOPHYTA
A division of plants comprising green plants with a vascular system that contains tracheids or tracheary elements, being the Pteridophyta and Spermatophyta, commonly called vascular plants.



TRACHEOPHYTE
Any member of the clade of plants possessing vascular tissue; a vascular plant.



TRACTIVE FORCE
The horizontal component of a tide producing force vector (directed parallel with level surfaces at that geographic location).



TRANSDUCIN
A regulatory g-protein in photoreceptors which stimulates phosphodiesterase molecules and acts as an amplifier of the incoming light signal.



TRANSDUCTION
Viral transfer of DNA to new host.



TRANSFORMATIONAL APPARENT MOTION
Apparent motion in which the presented object(s) appear to change shape, growing or contracting. In the simplest case, the line motion illusion, a line that is presented rapidly after a spot appears to smoothy grow out of the spot. There are many variations of this phenomenon. (See also APPARENT MOTION).



TRANSIENT TRITANOPIA PHENOMENON
Transient blindness for blue test lights is observed in the first few hundred milliseconds after the offset of strong yellow adaptations lights.



TRANSIT
The passage of a celestial body over a specified meridian.



TRANSMISSIVITY
The capacity of an aquifer to transmit water.



TREATMENT
Any method, technique or process, including neutralization, designed to change the physical, chemical or biological character or composition of any hazardous waste energy or material resource from the wastes.



TREE
Tall plant with a central trunk. The term does not imply anything about relationships, but is a growth pattern that has evolved several times in plants.



TRICHOCYST
Organelle in ciliates and dinoflagellates which releases long filamentous proteins when the cell is disturbed. Used as a defense against would-be predators.



TRICHOME
An outgrowth of the plant epidermis, either hairs or scales; a hair tuft; any hairlike outgrowth of the epidermis.



TRICHROMATIC COLOR VISION
Color vision based on three cone photoreceptors pigments in the retina



TRIGONAL
Triangular in cross-section as applied to stems.



TRIGONOUS
Trigonal; having three prominent longitudinal angles, as a style or ovary.



TRIMEROUS
Composed of three or multiples of three.



TRIPLOID
Having or being a chromosome number three times the monoploid number.



TRIQUETROUS
Triangular; having a triangular cross section.



TRISTICHOUS
Arranged in three vertical rows.



TROLAND
The unit of retinal illuminance defined as T=Lp with L (luminance) expressed in and p (pupil area) in mm2. Needed as luminance of the light incident on the retina varies with pupil size. There is a photopic and scotopic troland.



TROPIC CURRENTS
Tidal currents occurring semimonthly when the effect of the Moon's maximum declination is greatest.



TROPIC INEQUALITIES
The average difference between the two high waters of the day at the times of tropic tides.



TROPIC INTERVALS
The lunitidal interval pertaining to the higher high waters at the time of the tropic tides.



TROPIC RANGES
The difference in height between tropic higher high water and tropic lower low water.



TROPIC SPEED
The greater flood or greater ebb speed at the time of tropic currents.



TROPIC TIDES
Tides occurring semimonthly when the effect of the Moon's maximum declination is greatest.



TROPICAL
Region in which the climate undergoes little seasonal change in either temperature or rainfall. Tropical regions of the earth lie primarily between 30 degrees north and south of the equator.



TROPICAL MONTH
The average period of the revolution of the Moon around the Earth with respect to the vernal equinox.



TROPICAL YEAR
The average period of the revolution of the Earth around the Sun with respect to the vernal equinox.



TROUGH
The lowest point in a propagating or standing wave.



TRUNCATE
Terminating abruptly, as if tapering end were cut off; cut squarely across, either at the base or apex of an organ.



TRUNK
The main stem or body of a tree, considered apart from its roots and branches.



TSUNAMI
A shallow water progressive wave, potentially catastrophic, caused by an underwater earthquake or volcano.



TUBER
The short, thickened fleshy food-storing portion of an underground stem with many surface buds, generally shaped like a rounded protuberance.



TUBERCLE
A small rounded protuberance; root swelling or nodule; bubil; a surficial nodule; a thickened, solid, spongy crown or cap, as on an achene; a small tuber or tuberlike growth.



TURBINATE
Inversely conical; shaped like a cone resting on its apex.



TURGOR PRESSURE
Force exerted outward on a cell wall by the water contained in the cell. This force gives the plant rigidity, and may help to keep it erect.



TURION
Young scaly shoot budded off from underground stems, detachable winter bud used for perennation in many aquatic plants.



TURPENTINE
Distilled pine oil, used as a cleaner, solvent or thinner for oil-based and alkyd coatings.



TURTLE EXCLUDER
A device which must be placed on each tow net used by commercial shrimpers and fisherman.



TWIG
A small shoot or branch of a tree or other plant.



Twirl
[Synchronized Swimming] A rapid twist of 180 degrees.



Twist
[Synchronized Swimming] A rotation at sustained height.



Twist spin
[Synchronized Swimming] A move that involves a half-twist followed, without a pause, by a continuous spin.



UMBEL
An arrangement of flowers springing from a common center and forming a flat or rounded cluster.



UMBELLATE
Bearing umbels; consisting of umbels; forming an umbel or umbels.



UNCONFINED AQUIFER
The saturated formation in which the upper surface fluctuates with addition or subtraction of water.



UNCONFORMITY
Any interruption of the continuity of a depositional sequence.



UNDULIPODIUM
Another term for a eukaryotic flagellum.



UNISEXUAL
Of one or other sex, staminate or pistillate only, but not both.



UNIVERSAL TIME
Same as Greenwich mean time.



UNSATURATED FORMATION
The soil or other geologic material usually located between the land surface and a saturated formation where the voids, spaces or cracks are filled with a combination of air and water.



UPLANDS
Land above the mean high water line (shoreline) and subject to private ownership, as distinguished from tidelands, the ownership of which is prima facie in the state but also subject to divestment under state statutes.



UPWELLING
1. The raising of benthic nutrients to the surface waters. This occurs in regions where the flow of water brings currents of differing temperatures together, and increases productivity of the ecosystem; 2. An upward flow of subsurface water due to such causes as surface divergence, offshore wind, and wind drift transport away from shore.



URCEOLATE
Shaped like a pitcher or urn.



URETHANE
An important resin in the coatings industry.



UTRICLE
An air bladder of aquatic plants; membranous indehiscent 1-celled fruit.



VACUOLE
Membrane-bound fluid-filled space within a cell. In most plant cells, there is a single large vacuole filling most of the cell's volume. Some bacterial cells contain gas vacuoles.



VADOSE ZONE
[See UNSATURATED FORMATION]



VAGAL
Pertinent to the vagus nerve- the tenth cranial nerve. it is a mixed nerve, having motor and sensory functions and a wider distribution than any of the other cranial nerves.




VALVATE
Meeting at the edges without overlapping; opening as if by doors or valves.



VANISHING TIDE
In a predominantly mixed tide with very large diurnal inequality, the lower high water (or higher low water) becomes indistinct (or vanishes) at times of extreme declinations.



VARIATION
(of compass) Difference between true north as determined by the Earth's axis of rotation and magnetic north as determined by the Earth's magnetism.



VARIATIONAL INEQUALITY
An inequality in the Moon's motion due mainly to the tangential component of the Sun's attraction.



VARIETY
A taxonomic group below the species used in different senses by different specialists, including a race, stock, strain, breed, subspecies, geographical race, or mutant.



VASCULAR
Refers to the xylem and phloem tissues, which conduct water and nutrients through the plant body.



VASCULAR BUNDLE
A group of specialized cells consisting of xylem and phloem, sometimes separated by a strip of cambium and arranged in different patterns.



VASCULAR CAMBIUM
Lateral meristem that forms the secondary tissue and is located between the xylem and phloem.



VECTOGRAPH
A photograph consisting of varing degrees of polarization based on photographic content. Typically used to make stereoscopic photographs or slides that are viewed with special polarized glasses.



VEGETATIVE GROWTH
Growth of a plant by division of cells, without sexual reproduction.



VEHICLE
Portion of a coating that includes all liquids and the binder.



VELAMEN
A membrane; water-storing tissue in the outer layer of some roots.



VELOCITY
(of current) Speed and set of the current.



VELOCITY FIELD
A vector representation of the velocity of image motion of many small regions of a time-varying image



VENATION
The arrangement and pattern of veins in a leaf.



VENTRAL PATHWAY
One of two theorized systems of visual information processing. Information though to progress toward the temporal cortex V1-> V2 -> V4 -> IT. Functions for analysis of object qualities such as pattern shapes, size and colors. (See also DORSAL PATHWAY).



VERNAL
Belonging to the spring; appearing or occurring in spring; of the spring season.



VERNIER ACUITY
The ability to judege whether two line segments are collinear.



VERRUCOSE
Warty; having little warts or wartlike growth on the surface.



VERSATILE
Turning freely on its support, as an anther attached near the middle and capable of swinging freely on the filament.



VERTICAL DATUM
For marine applications, a base elevation used as a reference from which to reckon heights or depths.



Vertical position
[Synchronized Swimming] A position where the body is extended, with face, chest, thighs and feet at the surface.



VERTICIL
An arrangement of leaves, flowers, inflorescences, or other structures which surround the stem in a circle upon the same plane about the same point on the axis.



VERTICILLATE
Growing in a whorl or arranged on the same plane around an axis, as flowers, leaves, branches, etc.; arranged in verticils, whorled.



VESICLE
Any small bladderlike structure, cavity, sac, or cyst; a small bladderlike sac filled with air.



VESTITURE
That which covers a surface, as hairs, scales, etc.



VIETH-MULLER CIRCLE
When the foveal centers are pointed at an object, the range for which images of all other objects fall on corresponding points of zero horizontal disparity. This differs from the perceived range of zero disparity, the Horopter.



VILLOUS
Pubescent; shaggy; covered with fine long hairs, but the hairs not matted.



VINYL
[See POLYVINYL CHLORIDE]



VISCID
Thick, sirupy, and sticky, viscous; covered with a viscid substance as of leaves.



VISCOSITY
The property of a fluid whereby it tends to resist relative motion within itself.



VISUAL ANGLE
A measurement of the area of the retina in degrees subtended by a stimulus. Roughly speaking the width of one's thumb at arm's length is approximately 2 degrees.



VISUAL CLIFF
Apparatus consisting of a raised platform which divides two surfaces with optical texture (i.e. checkerboard pattern) covered with glass sheets. One is at a similar level to the platform, one is at a lower level. The optical information of the lower level produced the perception of a steep drop. Young animals of all species which guide themselves primarily by vision avoid venturing onto the glass covering the deep side.



VISUAL INTERFEROMETRY
Technique which allows the use of fine spacial patterns at much higher contrast than would be possible using ordinary optical techniques (because of optical blurring due to diffraction under ordinary conditions.) Uses a beam splitter to create an interference pattern.



VISUAL PHOSPHENE
The visual perception resulting from non-photopic stimulation such as electrical stimulation of the cortex or pressing on the eyeball. Brinkdley & Lewin 1968) and Bak et al (1990) have shown that stimulation of the cortex produces visual pherceptions.



VITREOMACULAR TRACTION SYNDROME
A traction-induced visual deficit in which partial posterior vitreous detachment is present in combination with persistent macular adherence.



VITREOUS HUMOR
Liquid filling the eye cavity.



VIVIPAROUS
1. Producing young alive rather than in eggs, as in most mammals; 2. multiplying by vegetative means such as buds or bulbils in the position of flowers.



VOC
[See VOLATILE ORGANIC COMPOUND]



VOLATILE ORGANIC COMPOUND
Organic chemicals and petrochemicals that emit vapors while evaporating.



VOLATILITY
The defining quality of a liquid that evaporates quickly when exposed to air.



VOLCANIC
Applies to igneous rocks that cool on the surface of the Earth, including beneath water; typically with small crystals due to the rapidity of cooling. Synonym of extrusive. Antonym of plutonic.



VOLUME SOLIDS
Solid ingredients as a percentage of total ingredients. The volume of pigment plus binder divided by the total volume, expressed as a percent.



Walkout front
[Synchronized Swimming] A move where, starting in the split position, the front leg is lifted in a 180-degree arc over the surface to meet the other leg in a surface-arch position, and with continuous movement an arch to back layout is executed.



WATER-BASED
Coatings in which the majority of the liquid content is water.



WATER TABLE
The upper level of a saturated formation where the water is at atmospheric pressure. The water table is the upper surface of an unconfined aquifer.



WATER TABLE AQUIFER
[See UNCONFINED AQUIFER]



WATERSHEDS
regional basins drained by or contributing water to a particular point, stream, river, lake or ocean.



WAVE HEIGHT
The vertical distance between crest and trough.



WEBER-FECHNER FUNCTION
Threshold versus intensity function



WEST WIND DRIFT
The largest permanent current in the world, setting eastward around the Antarctic Continent south of Cape Horn, Cape of Good Hope, Tasmania, and New Zealand.



WESTHEIMER PHENOMENON
Experiment of spacial summation at detection threshold that reveals the center-surround antagonism of individual neurons. A tiny test spot presented against background disks of varying diameter. The threshold for the test spot is first seen to rise then fall as the diameter of the background field increases.



WET WEIGHT
Same as fresh weight; weight of plants after the outer surface covering of water has been removed.



WET WOODLAND
A wooded area having surface water some of the time, for intermittent short periods.



WHEATSTONE STEREOGRAM
Fusing the two lines creates an image in depth with one line appearing to be above the other.



WHITE LEAD
Lead carbonate



WHORL
Circle of flowers, parts of a flower, or leaves arising from point; verticil.



WHORLED
When three or more leaves are arranged at the same level on a stem, typical of such plants as hydrilla.



WIND DRIFT
An ocean current in which only the Coriolis and frictional forces are significant.



WOODY
Of or containing wood or wood fibers; consisting mainly of hard lignified tissues.



XERIC
Characterized by a scanty supply of moisture, tolerating, or adapted to, arid conditions.



XYLEM
Woody tissue that is part of the water-transporting system in plants, consisting of lignified tracheids or vessels, and which also acts as a supporting tissue.



YIELD
Standing crop expressed as a rate, i.e., g dry weight per meter square per day.



ZOLLNER ILLUSION
Parallel lines appear tilted away from crossing lines depending on the angle of intersection. Claimed to be the result of competition/inhibition between orientations.



ZOOPLANKTON
Tiny, free-floating organisms in aquatic systems. Unlike phytoplankton, zooplankton cannot produce their own food, and so are consumers.



ZYGOMORPHIC
Said of the corolla or calyx when divisible into equal halves in one plane only bilaterally symmetrical, with only one plane of symmetry.



ZYGOTE
The product of gamete fusion. In organisms with a haploid life cycle, the zygote immediately undergoes meiosis, but in organisms with a multicellular diploid stage, the zygote is merely the first stage in the diploid portion of the life cycle.