Science terms starting with M

758 terms

[Marine] Natural Heritage The nation's biological communities, habitats, ecosystems, and processes, and the ecological services, uses, and values they provide to this and future…
[Marine] Natural Resources Any biological or physical component of the marine environment that contributes to the structure, function, or services provided by a marine ecosystem.
M 3000 In solar-terrestrial terms, the optimum high frequency radio wave with a 3000 km range, which reflects only once from the ionosphere (single hop…
M13 A single-stranded DNA bacteriophage used as a vector for DNA sequencing.
M13 strand The single-stranded DNA molecule that is present in the infective form of bacteriophage M13.
M2/S2 m2/s2 (meters squared per second squared), unit of measure equivalent to J/kg (joules per kilogram).
MAAP Abbreviation for multiple arbitrary amplicon profiling.
Maar A volcanic crater that is produced by an explosion in an area of low relief, is generally more or less circular, and often contains a lake, pond, or marsh.
MAB Abbreviation for monoclonal antibody.
macerate To disintegrate tissue to disrupt cells. Commonly achieved via mechanical shearing, plasmolysis or enzymatic cell wall degradation.
Mackeral Sky The name given to cirrocumulus clouds with small vertical extent and composed of ice crystals. The rippled effect gives the appearance of fish scales.
Macroburst A convective downdraft with an affected outflow area of at least 2Â½ miles wide and peak winds lasting between 5 and 20 minutes.
Macroclimate The climate representative of relatively large area.
Macrohabitat An extensive habitat presenting considerable variation of the environment, containing a variety of ecological niches and supporting a large number and…
macromolecule Any high molecular weight molecule. Often used as a synonym for polymers.
macronutrient A major chemical element essential for normal growth and development. In tissue culture media, macronutrients are those required in concentrations above 0.
macrophage A type of white blood cell that surrounds and kills microorganisms, removes dead cells, and stimulates the action of other immune system cells.
Macrophyte (aquatic) An aquatic plant that is large enough to be observed with the naked eye. It grows in or near water.
Macrophytes A plant large enough to be seen by the naked eye.
macropropagation Production of plant clones from growing parts.
Macrorestriction map Map depicting the order of and distance between sites at which restriction enzymes cleave chromosomes.
Macroscale Large scale, characteristic of weather systems several hundred to several thousand kilometers in diameter.
macrospore See: megaspore.
mad cow disease Colloquial term for bovine spongiform encephalopathy. See proteinaceous infectious particle
Madden-Julian Oscillation (abbrev. MJO)- Tropical rainfall exhibits strong variability on time scales shorter than the seasonal El NiÃ±o-Southern Oscillation (ENSO).
MADS box A highly conserved DNA sequence motif found in a large family of transcription factors, most of which play important roles in developmental processes.
Mafic (or maphic) A term used to describe an igneous rock that has a large percentage of dark-colored minerals such as amphibole, pyroxene, and olivine.
MAFOR (Great Lakes Marine Forecast) - A National Weather Service coded summary appended to each of the Great Lakes Open Lakes forecasts.
Magenta Used in four color printing. Reflects blue & red and absorbs green.
Magflare In solar-terrestrial terms, a geomagnetic and/or cosmic storm has been associated with this flare
Magma Molten or partially molten rock at temperatures ranging from 1,260 F to 2,880 F (700 C to 1600 C).
Magnetic Ballast A type of florescent light ballast that uses a magnetic core to regulate the voltage of a florescent lamp.
Magnetic Bay In solar-terrestrial terms, a relatively smooth excursion of the H (horizontal) component of the geomagnetic field away from and returning to quiet levels.
Magnetic Field A field of force around the Sun and the planets, generated by electrical currents, in which a magnetic influence is felt by other currents.
Magnetic Field Lines A magnetic field has both a strength and a direction at each point in space. For example, at each point Earth, the magnetic field -- and thus a compass --…
Magnetic Loops Field lines illuminated by hot plasma flowing along the magnetic field lines.
Magnetic pole Magnetic Pole Either of the two points on the Earth's surface at which magnetic meridians converge.
Magnetic Storms and Substorms A series of terrestrial disturbances – namely, the precipitation of auroras and rapid changes in Earth's magnetic field – caused by high-speed blasts…
Magnetism A force generated by electrical currents and changing electric fields. Magnetism is responsible for almost every feature in the solar atmosphere, from…
Magnetogram A magnetogram is an image of the Sun's magnetic flux. They are derived by using emission lines which are magnetically sensitive, which allows the magnetic…
Magnetopause In solar-terrestrial terms, the boundary layer between the solar wind and the magnetosphere.
Magnetosphere An area around a planet in which the planet’s magnetic field is stronger than the magnetic field carried by the solar wind.
Magnetotail The long magnetic tail of a magnetosphere drawn out by the flow of the solar wind.
Magnitude A rating of a given earthquake, independent of the place of observation. It is calculated from measurements on seismographs and it is expressed in…
Magnuson-Stevens Fishery Conservation and Management Act The Magnuson-Stevens Fishery Conservation and Management Act (MSA) is the primary law governing marine fisheries management in United States federal…
Main The principal pipe artery to which branches may be connected.
Main channel The deepest or central part of the bed of a stream, containing the main current.
Main channel pool Reach of a stream or river with a low bed elevation, relative to rapids or riffles.
Main Sequence Star A star that lies along a continuous band, known as the main sequence, extending from the upper left (hot, bright stars) to the lower right (cool, dim…
Main Stem The reach of a river/stream formed by the tributaries that flow into it.
Main Synoptic Times The times of 0000, 0600, 1200, and 1800 UTC. Also known as the standard synoptic times.
Mainstream (mainstem) The main course of a stream where the current is the strongest.
MAINT Maintain
maintenance The patent fees due at 4, 8 and 12 years needed to keep a U. S. utility or plant patent in force for its full life.
Maintenance area Any geographic region of the United States previously designated nonattainment pursuant to the CAA Amendments of 1990 and subsequently redesignated to…
Maintenance management system Any organized system used to ensure that all operations and maintenance activities (e.g.
Major facility A term used by Reclamation to describe those facilities for which an examination is conducted every third year, alternately conducted by the Denver and…
Major Flare In solar-terrestrial terms, this flare is the basis for the forecast of geomagstorm, cosmic storm and/or protons in the earth's vicinity
Major Flooding A general term including extensive inundation and property damage. (Usually characterized by the evacuation of people and livestock and the closure of…
major histocompatibility antigen A cell-surface protein or glycoprotein that allows the immune system to distinguish foreign or "non-self" from "self". A better term is histoglobulin.
major histocompatibility complex (Abbreviation: MHC). The large cluster of genes that encode the major histocompatibility antigens in mammals.
Major histocompatibility complex (MHC) A group of genes that code for cell-surface histocompatibility antigens. These antigens are the primary reason why organ and tissue transplants from…
Major Hurricane A hurricane which reaches Category 3 (sustained winds greater than 110 mph) on the Saffir/Simpson Hurricane Scale.
Major source A source that emits, or has the potential to emit, a pollutant regulated under the Clean Air Act in excess of a specified rate in a nonattainment area.
Make-Up Air Air brought into a building from outside to replace exhaust air.
malformation A structural defect inherited in an organ or part of an organ that results from abnormal fetal development. See also syndrome
Malignant (muh-LIG-nunt) Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.
MALR Moist Adiabatic Lapse Rate- The rate at which the temperature of a parcel of saturated air decreases as the parcel is lifted in the atmosphere.
malt extract A mixture of organic compounds prepared from malt, used as a culture medium additive.
malting Enzymatic reduction of starch to sugars in germinating grain, used in brewing.
Mammals A group of air-breathing animals whose skin is more or less covered with hair or fur and who have mammary glands.
mammary gland Glandular organ located on the chest. The mammary gland is made up of connective tissue, fat, and tissue that contains the glands that can make milk.
Mammatus Clouds Rounded, smooth, sack-like protrusions hanging from the underside of a cloud (usually a thunderstorm anvil).
Management activities Planned activities initiated by land managers to meet the desired future condition for an area.
Management area Management areas are specific geographical areas defined by a forest plan. Each management area has a set of objectives and a management prescription…
Management indicator species Species selected as ecological indicators. The welfare of a management indicator species is presumed to be an indicator of the welfare of other species…
management of farm animal genetic resources The sum total of technical, policy and logistical operations involved in understanding (characterization), using and developing (utilization), maintaining…
Management plan A plan guiding overall management of an area administered by a federal or state agency.
Management/Managing Agency or Authority The federal, state, commonwealth, territorial, local, or tribal entity or entities with legal authority to designate, promulgate regulations for, and/or…
Manifold (Header) A large pipe to which a series of smaller pipes are connected.
mannan The polymer of mannose with a repeating unit of C6H10O5. Can be hydrolyzed to mannose. (Source: Voet, D.; Voet, J. G. Biochemistry.
Manning's roughness coefficient (n) A coefficient used to describe the relative roughness of a channel and overbank areas; used in hydraulic computations.
mannitol (MA-nih-TOL) A drug used to decrease swelling of the brain and to treat kidney failure.
mannose A hexose component of many polysaccharides, occasionally used as a carbohydrate source in plant tissue culture media.
Mano A stone with a flat side that was primarily held in one's hand or hands and used to grind edible substances, typically corn, grains, and nut meats.
Manometer An instrument for measuring pressure.
Mantle The main bulk of the Earth, between the crust and core, ranging from depths of about 40 to 3,480 kilometers.
Mantle hot spot A region of continental or oceanic crust below which a mantle plume causes melting of the overlying crust, resulting in a broad regional topographic swell…
Manual J The standard method for calculating residential cooling loads developed by the Air-Conditioning and Refrigeration Institute (ARI) and the Air Conditioning…
Manuals. See publications.
Manure Dung and urine of animals that can be used as a form of organic fertilizer. See fertilizer, organic fertilizer.
MAP 1. verb: to determine the relative positions of loci (genes or DNA sequences) on a chromosome.
MAP (Mean Areal Precipitation) The average rainfall over a given area, generally expressed as an average depth over the area.
map distance The standard measure of genetic distance between loci, expressed in centiMorgans (cM) or map units .
map unit One centiMorgan (1 cM) See: map distance; crossing-over unit.
mapping Determining the physical location of a gene or genetic marker on a chromosome. (See Continuous map, Genetic map, Physical map.)
mapping function A mathematical expression relating observed recombination fraction to map distance.
Mapping population The group of related organisms used in constructing a genetic map.
Marble Metamorphic rock formed by the "baking" and recrystallization of limestone.
Mare's Trail The name given to thin, wispy cirrus clouds composed of ice crystals that appear as veil patches or strands, often resembling a horse's tail.