IsolatedA National Weather Service convective precipitation descriptor for a 10 percent chance of measurable precipitation (0.01 inch).
Isolated Solar Gain SystemA type of passive solar heating system where heat is collected in one area for use in another.
isolating mechanismThe properties of an organism that prevent interbreeding (and therefore exchange of genetic material) between members of different species that inhabit…
isolation mediumAn optimum plant tissue culture medium suitable for explant survival, growth and development.
isomerOne of two or more compounds that have the same chemical formula but different arrangements of the atoms within the molecules and that may have different…
isomeraseAny of a class of enzymes that catalyse the re-arrangement of the atoms within a molecule, thereby converting one isomer into another.
Isometric transitionA mode of radioactive decay where a nucleus goes from a higher to a lower energy state. The mass number and the atomic number are unchanged.
IsoplethA broad term for any line on a weather map connecting points with equal values of a particular atmospheric variable (temperature, dew point, etc.).
IsotachA line connecting points of equal wind speed.
IsothermA line connecting points of equal temperature.
isotonicSolutions with the same osmotic potential, as a result of being of the same molar concentration.
isotope(I-soh-tope) A form of a chemical element in which the atoms have the same number of protons (part of the nucleus of an atom) but with a different number…
Isotopesatoms that have the same number of protons, but a different number of neutrons are isotopes of each other.
Isotropicthe property of being independent of direction. Isotropic radiation has the same intensity regardless of the direction of measurement.
Isotropic massA mass having the same property (or properties) in all directions.
isozymeA genetic variant of an enzyme. Isozymes for a given enzyme share the same function, but may differ in level of activity, as a result of minor differences…
ISSRAbbreviation for inter-simple sequence repeat.
IssuesUnresolved conflicts regarding alternative uses of available resources. Subjects of public interest.
ITCZInter-tropical Convergence Zone. The region where the northeasterly and southeasterly tradewinds converge, forming an often continuous band of clouds or…
J/kgJoules per kilogram, unit commonly used to represent CAPE and CIN.
JacketThe enclosure on a water heater, furnace, or boiler.
January ThawA period of mild weather popularly supposed to recur each year in late January.
Jeopardy opinionU.S. Fish and Wildlife Service (FWS) or National Marine Fisheries Service (NMFS) opinion that an action is likely to jeopardize the continued existence of…
JetWhen air is sent at a high velocity through the carburetor, jets direct the fuel into the airstream.
Jet fuelIncludes both naphtha-type and kerosene-type fuels meeting standards for use in aircraft turbine engines.
Jet Max( or Jet Streak) A point or area of relative maximum wind speeds within a jet stream.
Jet StreakSame as Jet Max; a point or area ("streak") of relative maximum wind speeds within a jet stream.
Jet Stream(abbrev. JSTR) Relatively strong winds concentrated in a narrow stream in the atmosphere, normally referring to horizontal, high-altitude winds.
Jet Stream CirrusA loose term for filamentous cirrus that appears to radiate from a point in the sky, and exhibits characteristics associated with strong vertical wind…
Jet Wind Speed ProfileA vertical wind speed profile characterized by a relatively narrow current of high winds with slower moving air above and below.
Jet-flow gateA gate consisting of a wheel-mounted leaf moved vertically by a motor-driven screw hoist.
JettingA method of compacting soil using a hose or other device, with a high velocity stream of water, worked down through the depth of soil placed.
Jetting pumpA water pump that develops very high discharge pressure.
JettyPier or other structure built out into a body of water to influence the current or tide, or to protect a harbor or shoreline.
Jiffy potäPots made from wood pulp and peat, commonly used for transplanting tissue culture -derived plants into soil medium.
JitneyPrivately-owned, small or medium-sized vehicle usually operated on a fixed route but not on a fixed schedule.
JIVETAbbreviation for juvenile in vitro embryo technology.
JIVTAbbreviation for juvenile in vitro embryo technology.
Job hazard analysis (JHA)A study of a job or activity to identify hazards or potential accidents associated with each step or task, and develop solutions that will eliminate…
JoggingThe frequent starting and stopping of an electric motor.
Joining (J) segmentA small DNA segment that links genes to yield a functional gene encoding an immunogobulin.
joining segment(Abbreviation: J). A small DNA segment that links genes in order to yield a functional gene encoding an immunoglobulin.
JointSee expansion joint, cold joint, construction joint, contraction joint, and control joint.
Joint implementationAgreements made between two or more nations under the auspices of the United Nations Framework Convention on Climate Change to help reduce greenhouse gas…
Joint information centerA single location where public information officials gather to collaborate on, and coordinate the release of, emergency public information.
Joint use capacityThe reservoir capacity assigned to flood control purposes during certain periods of the year and to conservation purposes during other periods of the year.
JoistOne of a series of parallel timber beams used to support floor and ceiling loads, and supported in turn by larger beams, girders, or bearing walls; the…
JokulhlaupAn Icelandic term meaning glacier dammed lake outburst flood.
JouleA metric unit of energy or work; the energy produced by a force of one Newton operating through a distance of one meter; 1 Joule per second equals 1 Watt…
Joule's LawThe rate of heat production by a steady current in any part of an electrical circuit that is proportional to the resistance and to the square of the…
JSTRJet Stream - Relatively strong winds concentrated in a narrow stream in the atmosphere, normally referring to horizontal, high-altitude winds.
JunctionA region of transition between semiconductor layers, such as a p/n junction, which goes from a region that has a high concentration of acceptors (p-type)…
Junior water rightsWater rights that are more recent than older or more senior rights. See also Senior water rights
Jurisdiction(1) The legal authority of a court to hear and decide a case. Concurrent jurisdiction exists when two courts have simultaneous responsibility for the same…
Just-in-time orderingA strategy for managing materials used at a project that ensures materials become available as needed to support activities, but are not stockpiled at the…
JuvenileYoung fish older than 1 year but not capable of reproduction.
juvenile hormoneA hormone secreted by insects from a pair of endocrine glands close to the brain.
juvenile in vitro embryo technology(Abbreviation: JIVT or JIVET). A technology involving collection of immature eggs from young animals, their in vitro maturation and fertilization, and the…
Juvenile salmonAll early lifestages of downstream migrating salmon (fry through smolt).
Juvenile WaterWater formed chemically within the earth and brought to the surface in intrusive rock.
juvenilityEarly phase of development in which an organism is incapable of sexual reproduction.
KSmoke- Smoke in various concentrations can cause significant problems for people with respiratory ailments.
K CoronaIn solar-terrestrial terms, of the white-light corona (that is, the corona seen by the eye at a total solar eclipse), that portion which is caused by…
K-captureThe capture by an atom's nucleus of an orbital electron from the first K-shell surrounding the nucleus.
K-IndexA measure of the thunderstorm potential based on vertical temperature lapse rate, moisture content of the lower atmosphere, and the vertical extent of the…
KanamycinAn antibiotic of the aminoglycoside family that poisons translation by binding to the ribosomes.
kanrKanamycin resistance gene. (See Selectable marker.)
Kaplan TurbineA type of turbine that has two blades whose pitch is adjustable. The turbine may have gates to control the angle of the fluid flow into the blades.
kappa chainOne of two classes of antibody light chains. The other is a lambda chain.
karyogamyThe fusion of nuclei or nuclear material that occurs at fertilization during sexual reproduction.
karyogramA diagrammatic representation of the full chromosome set of a species, highlighting characteristic physical features of individual chromosomes.
karyokinesisThe division of a cell nucleus. See: meiosis; mitosis.
KaryotypeAll of the chromosomes in a cell or an individual organism, visible through a microsope during cell division.
Katabatic WindA wind that is created by air flowing downhill.
KatafrontA front where the warm air descends the frontal surface (except in the low layers of the atmosphere).
KBAbbreviation for kilobase (of single-stranded nucleic acid).