Science — page 97 of 132

13,110 terms including subtopics (0 terms filed directly here)

Science terms

Pueblo rights A water right possessed by a municipality which, as a successor of a Spanish or Mexican pueblo, entitled to the beneficial use of all needed…
Puget Sound Convergence Zone A situation where wind forced around the Olympic Mountains converges over the Puget Sound.
Pull shovel (dragshovel or hoe) A shovel with a hinge-and-stick mounted bucket that digs while being pulled inward.
Pulp chips Timber or residues processed into small pieces of wood of more or less uniform dimensions with minimal amounts of bark.
Pulse A short burst of electromagnetic energy that a radar sends out in a straight line to detect a precipitation target.
Pulse Duration The time over which a radar pulse lasts. The pulse duration can be multiplied by the speed of light to determine the pulse length or pulse width.
Pulse Length The linear distance in range occupied by an individual pulse from a radar. h = c * t , where t is the duration of the transmitted pulse, c is the speed of…
Pulse Radar A type of radar, designed to facilitate range (distance) measurements, in which are transmitted energy emitted in periodic, brief transmission.
Pulse Repetition Frequency (PRF) The amount of time between successive pulses, or bursts, of electromagnetic energy that is transmitted by a radar.
Pulse Repetition Time (PRT) The time elapsed between pulses by the radar. This is also called the pulse interval.
Pulse Resolution Volume A discrete radar sampling volume, of dimensions (horizontal beamwidth * vertical beamwidth * 1 range gate).
Pulse Severe Thunderstorms Single cell thunderstorms which produce brief periods of severe weather (3/4 inch hail, wind gusts in the excess of 58 miles an hour, or a tornado).
Pulse Storm A thunderstorm within which a brief period (pulse) of strong updraft occurs, during and immediately after which the storm produces a short episode of…
Pulse Width Same as Pulse Length; the linear distance in range occupied by an individual pulse from a radar.
Pulse-Pair Processing Nickname for the technique of mean velocity estimation by calculation of the signal complex covariance argument.
Pulse-Width-Modulated (PWM) Wave Inverter A type of power inverter that produce a high quality (nearly sinusoidal) voltage, at minimum current harmonics.
pulsed-field gel electrophoresis (Abbreviation: PFGE). A procedure used to separate very large (50 kbp to several Mbp) DNA molecules by alteRNA ting the direction of electric current in a…
Pump See centrifugal pump, diaphragm pump, jetting pump.
Pump Octane Number This number represents the ability of a fuel to resist knocking when ignited in the cylinder of an internal-combustion engine.
Pump-back system A return-flow system in which tailwater is pumped back to the head of an irrigation ditch for reuse.
Pumped Storage Facility A type of power generating facility that pumps water to a storage reservoir during off-peak periods, and uses the stored water (by allowing it to fall…
Pumped-storage plant Powerplant designed to generate electric energy for peakload use by releasing water previously pumped into an elevated storage reservoir, usually during…
Pumping Mechanical transfer of fluids.
Pumping energy Energy required to pump water from the lower reservoir to the upper reservoir of a pumped-storage plant.
Pumping Head Energy given to a fluid by a pump, usually expressed in feet of fluid (foot pounds per pound).
Pumping plant Facility that lifts water up and over hills.
Pumplift (pumping lift) The vertical distance that a pump will raise waters. Distance water must be lifted in a well from the pumping level to the ground surface.
punctuated equilibrium The occurrence of speciation events in bursts, separated by long intervals of species stability.
Purchase of Development Rights Programs through which local governments may purchase development rights and dedicate the land for conservation easements, protecting it as open space or…
Purchased power Normally this type is used to represent the purchase cost of energy for firming up the power supply.
pure line A strain in which all members are genetically nearly identical and are indistinguishable by phenotype.
purification tag See: affinity tag.
Purine A double-ring, nitrogen-containing base present in nucleic acids . Adenine (A) and guanine (G) are the two purines normally present in DNA and RNA…
Purveyor An agency or person that supplies water.
PVA The Plant Variety Act. See U.S. Department of Agriculture.
PVL Prevail
PvP Player vs. Player. This means for one player to attack another player.
PVR Abbreviation for plant variety rights.
pW Precipitable Water - measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column…
PWAT Precipitable Water - measure of the depth of liquid water at the surface that would result after precipitating all of the water vapor in a vertical column…
PWO Public Severe Weather Outlook
PWP Abbreviation for permanent wilting point.
Pyranometer A device used to measure total incident solar radiation (direct beam, diffuse, and reflected radiation) per unit time per unit area.
pyrethrins Active constituents of pyrethrum (Tanacetum cinerariifolium) flowers, used as insecticides.
Pyrheliometer A device that measures the intensity of direct beam solar radiation.
Pyrimidine A single-ring, nitrogen-containing base present in nucleic acid s. Cytosine (C) and thymine (T) are present in DNA, whereas uracil (U) replaces T in RNA.
Pyroclastic Ash mixed with larger igneous rock fragments produced by explosive volcanic eruptions.
Pyroclastic flow High-speed avalanches of hot ash, rock fragments, and gas that move down the sides of a volcano during explosive eruptions or when the steep edge of a…
Pyroclastic surge Similar to a pyroclastic flow, but contains a higher proportion of gas to rock and is more turbulent and faster moving.
pyrogen Bacterial substance that causes fever in mammals.
Pyrolysis The transformation on a compound or material into one or more substances by heat alone (without oxidation). Often called destructive distillation.
pyrophosphate A phosphate ion dimer; may be released on hydrolysis of ATP.
Q Denotes the longer of the two chromosome arms, e.g. human 10q is the long arm of human chromosome 10.
q-beta replicase A viral RNA polymerase secreted by a bacteriophage that infects E. coli. It has the property of being able to copy RNA sequences at a rapid rate.
QG Quasigeostrophic
QN Question
QPF Quantitative Precipitation Forecast. A spatial and temporal precipitation forecast that will predict the potential amount of future precipitation for a…
QPF Discussion This HPC forecast discussion is directed completely to explaining manual forecasts of areas in the contiguous 48 states expected to receive 1/4 inch or…
QPFERD NCEP Excessive Rainfall Discussion
QPFHSD NCEP Heavy Snow Discussion
QPFPFD NCEP Precipitation Forecast Discussion
QSAR Abbreviation for quantitative structure-activity relationship.
QSTNRY Quasi-stationary - describes a low or high pressure area or a front that is nearly stationary.
QTL Abbreviation for quantitative trait locus.
QTR Quarter
Quad One quadrillion Btu. (1,000,000,000,000,000 Btu)
Quad-level occurrence The recorded occurrence of a species in the area represented by a specific, named U.S. Geological Survey 7.5-minute topographic quadrangle map (quad map).
Quadrat Sampling area, most commonly one square meter, used for analyzing vegetation. A square or rectangular plot of land marked off for the study of plants and…
Quadrature The component of the complex signal that is 90 degrees out of phase with the inphase component.
quadrivalent A chromosome configuration visible in late prophase and metaphase of the first meiotic division, where four chromosome s are linked by chiasmata.
quadruplex The inheritance of alleles in autotetraploids. A genotype AAAa will produce gametes AA, Aa in the ratio 3:1.
Qualifying Facility A category of electric power producer established under the Public Utility Regulatory Policy Act (PURPA) of 1978, that includes small-power producers…
Qualitative Having to do with quality or qualities. Descriptive of kind, type or direction, as opposed to size, magnitude or degree.
qualitative trait A trait that shows discontinuous variation - i.e. individuals can be assigned to one of a small number of discrete classes.
Quality Measurement Experiments (QME) (QME) A special class of value-added product that regularly compares two or more data sets intended to understand the individual datastreams either as functions…
Quality of Life The overall enjoyment of life. Many clinical trials assess the effects of cancer and its treatment on the quality of life.
Quality of Snow The amount of ice in a snow sample expressed as a percent of the weight of the sample.
quality-assured data Typically, the final form of data to be submitted to the ARM data system. Includes datastream description documentation, fully calibrated data in commonly…
Quantitative Having to do with quantity, capable of being measured. Descriptive of size, magnitude or degree.
quantitative genetics The area of genetics concerned with the inheritance of quantitative traits that show continuous variation, as opposed to qualitative trait s.
quantitative inheritance Inheritance of measurable traits that depend on the cumulative action of many genes and/or involve a significant proportion of non-genetic determination.
Quantitative Precipitation Forecast A spatial and temporal precipitation forecast that will predict the potential amount of future precipitation for a specified region, or area.
Quantitative Precipitation Forecast (QPF) (QPF) A spatial and temporal precipitation forecast that will predict the potential amount of future precipitation for a specified region, or area.
Quantitative precipitation forecasts A projection that uses the interpretation of various observational, numerical, and objective aids to estimate the amount, location, and duration of…
quantitative structure-activity relationship (Abbreviation QSAR). A computer modelling technique that enables the prediction of the likely activity of a molecule before it is synthesized.
quantitative trait A measurable trait that shows continuous variation (e.g. height, weight, colour intensity, etc.) - i.e.
quantitative trait locus (Abbreviation: QTL). A locus where is associated with variation in a quantitative trait.
Quantum Fluctuations Tiny changes in the energy of the vacuum.
Quantum Mechanics A theory of physics that is applicable to systems of extremely small scales (ie. the size of an atom). QM quantifies the "fuzzyness" of the universe.
quantum speciation The rapid formation of new species, primarily by genetic drift.
quarantine Isolation for a period after arrival in a new location, to allow any pre-existing disease symptoms to appear.
Quark A fundamental matter particle that has strong interactions. Quarks have electric charge of either +2/3 (up, charm, top) or -1/3 (down, strange, bottom) in…
Quarry A rock pit. An open cut mine in rock chosen for physical rather than chemical characteristics.
Quartz Very hard, clear or translucent mineral composed of silica.
Quartzite A hard, metamorphic rock that was originally sandstone.
Quasar Short for Quasi-stellar Radio Source. A quasar behaves like a small galaxy powered by a super massive black hole, most of the time.
Quasi-stationary (abbrev. QSTNRY)- Describes a low or high pressure area or a front that is nearly stationary.
Quasi-stationary Front A front which is nearly stationary or moves very little since the last synoptic position. Also known as a stationary front.
Quaternary The present period, forming the latter part of the Cenozoic Era, originating about 1 million years ago and including the Recent and Pleistocene epochs.
Quaternary period the second period of the Cenozoic era containing the Pleistocene epoch and the Holocene epoch and lasting from 1.8 million years to the present.