disarmThe deletion from a plasmid or virus of genes that are pathogenic.
DisasterAn event that demands a crisis response beyond the scope of any single line agency or service (e.g.
Discharge(DIS-charj) In medicine, a fluid that comes out of the body. Discharge can be normal or a sign of disease.
Discharge capacityThe maximum amount of water that can safely released from a given waterway.
Discharge CurveA curve that expresses the relation between the discharge of a stream or open conduit at a given location and the stage or elevation of the liquid surface…
Discharge Table(1) A table showing the relation between two mutually dependant quantities or variable over a given range of magnitude.
discontinuous variationVariation where individuals can be classified as belonging to one of a set of discrete, non-overlapping classes.
discordantMembers of a pair showing different, rather than similar, characteristics.
Discount rateThe discount rate is the interest rate the Federal Reserve charges on loans it makes to banks and other financial institutions.
DiscountingA method of financial and economic analysis used to determine present and future values of investments or expenses.
DisdrometerEquipment that measures and records the size distribution of raindrops.
disease resistanceThe genetically determined ability to prevent the reproduction of a pathogen, thereby remaining healthy.
Disease-associated genesAlleles carrying particular DNA sequences associated with the presence of disease.
disease-freeA plant or animal certified through specific tests as being free of specified pathogens .
disease-indexingDisease-indexed organisms have been assayed for the presence of known diseases according to standard testing procedures.
Dish engineThe dish engine is a concentrating solar power (CSP) technology that produces electricity, typically in the range of 3 to 25 kilowatts, by using a…
disinfectionAttempted elimination by chemical means of internal micro-organisms (particularly pathogens) from a culture or sample; rarely attained. See: sterilize (1).
disinfestationThe elimination or inhibition of the activity of surface-adhering micro-organisms and removal of insects.
disjunctionSeparation of homologous chromosomes during anaphase I of meiosis, or of sister chromatids during anaphase of mitosis and anaphase II of meiosis.
diskThe visible surface of the sun (or any heavenly body) projected against the sky.
Dispatchable power (dispatchability)The ability of a power-producing facility to provide required amounts of power (at or below the facility's nameplate rating) on demand of the grid…
DispatchingTo schedule and control the generation and delivery of electric power.
dispenseThe transfer of a measured volume of a solution.
Dispersing agentAn agent used to assist in separating individual fine soil particles and to prevent them from flocculating when in suspension.
DispersionDistortion of the shape of a seismic-wave train because of variation of velocity with frequency.
DisplacementDisplacement is the replacement of a U.S. worker by an H-1B worker in an essentially equivalent job and occurs within the period beginning 90 days before…
Displacement PowerA source of power (electricity) that can displace power from another source so that source's power can be transmitted to more distant loads.
Displacement pumpReciprocating type of pump where a piston draws water into a closed chamber and then expels it under pressure.
DisposalA term used in some countries, including the U.S., to mean that an application has been abandoned, denied (rejected) or allowed (granted).
disrupter geneUsed to enforce the sterility of seed saved from a genetically engineered crop. See: genetic use restriction technology.
dissecting microscopeA microscope with a magnifying power of about 50x, used as an aid in the manipulation of small objects, e.g. excision of embryos from young zygotes.
dissectionSeparation of a tissue by cutting into components, for analysis or observation.
dissociationA chemical process by means of which a change in physical condition causes a molecule to split into simple groups of atoms, single atoms, or ions.
Dissolved oxygen (DO)Amount of free oxygen found in water; perhaps the most commonly employed measurement of water quality.
Distance zonesA subdivision of the landscape as viewed from an observer position. The BLM defined zones include foreground, middleground, background, and seldom seen.
distillateThe portion of a liquid that is removed as vapor and condensed during a distillation process.
Distillate fuel oilProducts of refinery distillation sometimes referred to as middle distillates; kerosene, diesel fuel, and home heating oil. No.
Distillate oilAny distilled product of crude oil. A light petroleum product used for home heating and most machinery.
distillationThe process of heating a mixture to separate the more volatile from the less volatile parts, and then condensing fractions of the resulting vapour so as…
distillers dried grains (DDG)The dried grain byproduct of the grain fermentation process, which may be used as a high-protein animal feed.
Distillers´ dried grains (DDG)The dried byproduct of the grain fermentation process. Typically used as a high-protein animal feed.
Distributed GenerationA term used by the power industry to describe localized or on-site power generation.
DistributionThe sale of securities. Also refers to a sum payable to shareholders representing their share of profits.
Distribution (Hydro)GraphA unit hydrograph of direct runoff modified to show the proportions of the volume of runoff that occur during successive equal units of time.
Distribution efficiencyMeasure of the uniformity of irrigation water distribution over a field.
Distribution LineOne or more circuits of a distribution system on the same line or poles or supporting structures' usually operating at a lower voltage relative to the…
Distribution SystemThat portion of an electricity supply system used to deliver electricity from points on the transmission system to consumers.
DistrictAn entity that has a contract with the Bureau of Reclamation for the delivery of irrigation water.
District EnergyA district energy system consists of a central plant that produces steam, hot water, or chilled water, to provide space heating, domestic hot water…
District HeatingA heating system in which steam or hot water for space heating or hot water is piped from a central boiler plant or electric power/heating plant to a…
District heating or coolingA system that involves the central production of hot water, steam, or chilled water and the distribution of these transfer media to heat or cool buildings.
disulphide bridgeA chemical bond between pairs of sulphur atoms that stabilizes the three-dimensional structure of proteins, and hence the protein 's normal function.
DitchGenerally, a long narrow excavation. Constructed open channel for conducting water.
ditypeIn fungi, a tetrad that contains two kinds of meiotic products (spores), e.g. 2AB and 2ab.
Diurnal CyclesVariations in meteorological parameters such as temperature and relative humidity over the course of a day which result from the rotation of the Earth…
Diurnal Temperature RangeThe temperature difference between the minimum at night (low) and the maximum during the day (high).
divergenceThe expansion or spreading out of a vector field; usually said of horizontal winds. It is the opposite of convergence.
DiversionThe process of removing some minor criminal, traffic or juvenile cases from the full judicial process, on the condition that the accused undergo some sort…
Diversion capacityThe flow which can be passed through the canal headworks at a dam under normal head.
Diversion channel (canal or tunnel)A waterway used to divert water from its natural course. The term generally applies to a temporary arrangement (e.g.
Diversion damA dam built to divert water from a waterway or stream into a different watercourse.
Diversion inletA conduit or tunnel upstream from an intake structure. Diversion inlet may be integral with the outlet works or be part of a separate conveyance structure…
DiversityThe distribution and abundance of different plants and animals within an area.
Diversity FactorThe ratio of the sum of the noncoincidental maximum demands of two or more loads to their coincidental maximum demands for the same period.
DivertTo direct a flow away from its natural course.
DivideA ridge or high area of land that separates one drainage basin from another.
Dividing StreamlineIn the blocked flow region upwind of a mountain barrier, the streamline that separates the blocked flow region near the ground from the streamlines above…
Dividing Streamline HeightThe height above ground of the dividing streamline, as measured far upwind of a mountain barrier. See dividing streamline.
dizygotic twinsTwo-egg twins, i.e. a pair of individuals that shared the same uterus at the same time, but which arose from separate and independent fertilization of two…
DNAThe molecules inside cells that carry genetic information and pass it from one generation to the next. Also called deoxyribonucleic acid.
DNA (deoxyribonucleic acid)An organic acid and polymer composed of four nitrogenous bases--adenine, thymine, cytosine, and guanine linked via intervening units of phosphate and the…
DNA amplificationMany-fold multiplication of a particular DNA sequence either in vivo in a plasmid, phage or other vector; or in vitro using, most commonly, the polymerase…
DNA amplification fingerprinting(Abbreviation: DAF). A arbitrarily primed polymerase chain reaction technique for obtaining molecular markers using very short (5-8 bp) primers.
DNA bankA service that stores DNA extracted from blood samples or other human tissue.
DNA constructA chimeric DNA molecule, carrying all the genetic information necessary for its transgenic expression in a host cell.
DNA delivery systemA generic term for any procedure that transports DNA into a recipient cell.
DNA diagnosisThe use of DNA polymorphisms to detect the presence of a disease gene.
DNA diagnosticsThe use of DNA polymorphisms to detect the presence of a specific sequence, which could indicate the presence of a contaminant, of a pathogen, or of a…
DNA fingerprintThe unique pattern of DNA fragments identified by Southern hybridization (using a probe that binds to a polymorphic region of DNA) or by polymerase chain…
DNA fingerprintingThe derivation of unique patterns of DNA fragments obtained using a number of marker techniques; historically these were RFLPs, but latterly they are…
DNA helicaseAn enzyme that catalyses the unwinding of the complementary strands of a DNA double helix. Synonym: gyrase.