microdroplet array(Abbreviation: MDA). A technique used to simultaneously evaluate large numbers of media modifications, employing small quantities of medium into which are…
MicroenvironmentThe molecules and compounds such as nutrients and growth factors in the fluid surrounding a cell in an organism or in the laboratory, which play an…
microfibrilMicroscopic fibres visible only at the high magnification of the electron microscope.
micropropagationMiniaturized in vitro multiplication and/or regeneration of plant material under aseptic and controlled environmental conditions.
micropyle1. A small opening in the surface of a plant ovule through which the pollen tube passes prior to fertilization. 2.
microsatelliteA short sequence of DNA, usually 1 to 4 basepairs (a unit of DNA), that is repeated together in a row along the DNA molecule.
MicroscalePertaining to meteorological phenomena, such as wind circulations or cloud patterns, that are less than 2 km in horizontal extent.
MicrositeA small area within an environment with unique features, conditions, or characteristics relative to the surrounding area.
microsporeThe immature male gametophyte in seed plants; the haploid male cell that ripens into a pollen grain.
Microsystem irrigationMethod of precisely applying irrigation water to the immediate root zone of the target plant at very low rates.
microtuberMiniature tuber, produced in tissue culture, which is readily regenerable into a normal tuberous plant.
MicrotubuleSelf-assembling components of the cytoskeleton. Microtubules are cylindrical protein polymers, interconnected by cross-bridging proteins, which…
MicrowaveA type of electromagnetic radiation with wavelengths between those of infrared radiation and radio waves.
Microwave BurstIn solar-terrestrial terms, a radiowave signal associated with optical and/or X-ray flares
microwave radiationElectromagnetic radiation generally in the frequency range between 300 MHz and 300 GHz (wavelengths between 1mm and 1m).
Mid seral speciesShade intolerant species, primarily Douglas-fir trees and vine maple shrubs. These species typically follow the early seral species in natural succession.
Mid seral treatmentA treatment in which a stand of predominately mid seral species will be established.
Mid-Flame WindWind measured at the midpoint of the flames, considered to be most representative of the speed of the wind that is affecting fire behavior.
Mid-Latitude AreasAreas between 30o and 60o north and south of the Equator.
Mid-level CoolingLocal cooling of the air in middle levels of the atmosphere (roughly 8 to 25 thousand feet), which can lead to destabilization of the entire atmosphere if…
mid-parent valueThe average of the phenotypic measure, with respect to a given trait, of the two parents used to generate the population being analysed.
Middle Clouds(or Mid-Level Clouds) - A term used to signify clouds with bases between 6,500 and 23,000 feet.
middle lamellaA thin exclusively plant membrane separating two adjacent protoplasts and remaining as a distinct cementing layer between adjacent cell walls.
Middle Latitudes1) The latitude belt roughly between 35 and 65 degrees North and South. Also referred to as the temperate region.
Middle-level cloudsMiddle-level clouds (Ac and As) Altocumulus and Altostratus are the middle-level clouds.
Mie ScatteringAny scattering produced by spherical particles whose diameters are greater than 1/10 the wavelength of the scattered radiation.
MigmatiteRock composed of a complex mixture of metamorphic rock and igneous granitic rock.
Migration corridorA route followed by animals such as big game, birds, or fish when traveling between winter and summer habitats.
MigratoryMoving from one area to another on a seasonal basis.
Migratory Bird Treaty Act (MBTA)The MBTA implements various treaties and conventions between the United States, and Canada, Japan, Mexico, and the former Soviet Union for the protection…
MILA unit of length equal to 0.001 of an inch. Used in measuring the diameter of wires, and the thickness of fabric and plastic sheeting.
MilestoneA measurable action, state, or goal which marks a point of achievement on the way to solving the problem.
Military crestA ridge that interrupts the view between a valley and a hilltop.
Military Training Route (MTR)A designated corridor of airspace with defined vertical and lateral dimensions established for conducting military flight training at airspeeds in excess…
Milky WayThe galaxy in which the Earth is found. When viewed from the Earth and its environs, it appears in the night sky as a hazy band of white light (hence…
MillA common monetary measure equal to one-thousandth of a dollar or a tenth of a cent.
Mill residueWood and bark residues produced in processing logs into lumber, plywood, and paper.
Mill/kWhA common method of pricing electricity. Tenths of a cent per kilowatt hour.
Million acre-feet (maf)The volume of water that would cover 1 million acres to a depth of 1 foot.
Millisecond delay (short period delay)A type of delay cap with a definite but extremely short interval between initiation, or passing of current, and explosion.
Millsite mining claimClaim on nonmineral land for processing ore from a mining claim.
Mineral Leasing Act of 1920 (MLA)Authorizes the agency to issue rights-of-way grants for oil and gas gathering and distribution pipelines and related facilities not already authorized…
Mineral materialsWidespread deposits of common clay, sand, gravel, or stone which are not subject to disposal under the 1872 Mining Law, as amended.
mineralizationThe conversion of organic compounds into inorganic (mineral) ones. For example, the conversion of ethanol into carbon dioxide and water.
Miners' InchA rate of discharge through an orifice one inch square under a specific head.
mini-prepA small-scale preparation of plasmid or phage DNA. Used to purify cloned DNA from the DNA of the vector.
MinigeneratorA trademark of Union Carbide Corporation that is used to identify radioisotope generator systems for educational use.
Minimal tillage practicesPractices that allow farmers to reduce the tilling of the land to conserve topsoil and its nutrients.
Minimum Discernible SignalIn a receiver, it is the smallest input signal that will a produce a detectable signal at the output.
minimum effective cell densityThe cell density below which reproducible cell growth fails. The minimum density is determined by both the source function of the tissue (species…
Minimum flowNegotiated lowest flow in a regulated stream that will sustain an aquatic population of agreed-upon levels. Flow may vary seasonally.
minimum inoculum sizeThe critical volume of inoculum required to initiate culture growth, due to the diffusive loss of cell materials into the medium.
Minimum operating levelThe lowest level to which the reservoir is drawn down under normal operating conditions.
Minimum TemperatureThis is the lowest temperature recorded during a specified period of time. The time period can be 6, 12 or 24 hours.
MiningUsually removal of soil or rock having value because of its chemical composition.
Mining claimThat portion of the public mineral lands which a miner, for mining purposes, takes and holds in accordance with the mining laws.
Mining water useWater use during quarrying rocks and extracting minerals from the land.
minisatelliteA form of variable number tandem repeats in which the repeat unit size ranges from 10-100 bp. Used for DNA fingerprinting following Southern hybridization.
minituberSmall tubers (5-15 mm in diameter) formed on shoot cultures or cuttings of tuber-forming crops, such as potato.
Minor FloodingA general term indicating minimal or no property damage but possibly some public inconvenience.
Minor Tidal OverflowMinor flooding caused by high tides that results in little if any damage.
Minority CarrierA current carrier, either an electron or a hole, that is in the minority in a specific layer of a semiconductor material; the diffusion of minority…
Minority populationIncludes Hispanic, American Indian, or Alaskan Native; Asian; Native Hawaiian or Other Pacific Islander; Black (not of Hispanic origin) or African…
MioceneAn epoch of the upper Tertiary period, 23 to 5.3 million years ago.
MirrorA reflecting surface of various physical shapes (parabolic, nearly flat, or flat) used to reflect and/or concentrate the sun's energy to specific…
mismatchThe occurrence of a non-complementary pairs of bases in a double helix of DNA, e.g. A:C, G:T.
mismatch repairA DNA repair process that corrects mismatched base pairs.
MisoscaleThe scale of meteorological phenomena that ranges in size from 40 meters to about 4 kilometers. It includes rotation within a thunderstorm.
missense mutationA mutation that changes a codon for one amino acid into a codon specifying another amino acid.
Mission of the Hydrologic Services ProgramTo provide river and flood forecasts and warnings for the protection of life and property and to provide basic hydrologic forecast information for the…
Mission of the National Weather ServiceTo provide weather and flood warnings, public forecasts and advisories for all of the United States, its territories, adjacent waters and ocean areas…