Stream capacityTotal volume of water that a stream can carry within the normal high water channel.
Stream classClassification of streams based on the present and foreseeable uses made of the water, and the potential effects of on-site changes on downstream uses.
Stream CorridorThe area (containing wetlands, flood plains, woodlands, unique habitats, and steep slopes) which lies between relatively level uplands and stream banks…
Stream GageA site along a stream where the stage (water level) is read either by eye or measured with recording equipment.
Stream lineAn imaginary line within the flow which is everywhere tangent to the velocity vector.
Stream SegmentRefers to the surface waters of an approved planning area exhibiting common hydrological, natural, physical, biological, or chemical processes.
Stream terraceA remnant of a floodplain surface formed by streams as they carve downward into their floodplains.
Streambed at the dam axisThe lowest-point elevation in the streambed at the axis or centerline crest of the dam prior to construction.
StreamflowDischarge that occurs in a natural channel.
StreetscapeThe space between the buildings on either side of a street that defines its character.
streptavidinA small bacterial protein that binds with high affinity to the vitamin biotin. This streptavidin-biotin combination can be used to link molecules such as…
StressThe response of the body to physical, mental, or emotional pressure. This may make a person feel frustrated, angry, or anxious, and may cause unhealthy…
stress protein(... PROH-teen) One of a group of proteins that help protect cells from stresses such as heat, cold, and low amounts of oxygen or glucose (sugar).
StressorsPhysical, chemical, or biological entities that can induce adverse effects on ecosystems or human health.
StriationScratch or groove in bedrock caused by rocks within a glacier grinding the earth's surface as the glacier moves.
StriationsGrooves or channels in cloud formations, arranged parallel to the flow of air and therefore depicting the airflow relative to the parent cloud.
StrikeStrike means a labor dispute wherein employees engage in a concerted stoppage of work (including stoppage by reason of the expiration of a collective…
Strike-slip faultVertical (or nearly vertical) fractures where the blocks have mostly moved horizontally.
StringencyReaction conditions--notably temperature, salt, and pH--that dictate the annealing of single-stranded DNA/DNA, DNA/RNA, and RNA/RNA hybrids.
Stringent plasmidA plasmid that only replicates along with the main bacterial chromosome and is present as a single copy, or at most several copies, per cell. (See plasmid.
Strip croppingA crop production system that involves planting alternating strips of row crops and close-growing forage crops; the forage strips intercept and slow…
Strip miningCutting deep trenches to remove minerals such as coal and phosphate found near the earth's surface in flat or rolling terrain. See surface mining.
StrippingRemoval of a surface layer or deposit for the purpose of excavating other material beneath it.
Stroma(stro' mah) the supporting tissue or matrix of an organ; as distinguished from the functional part of the organ.
StromalRelating to the stroma of an organ or other structure, that is, its framework, usually of connective tissue, rather than its specific substance.
Stromal cell(STROH-mul SEL) A type of cell that makes up certain types of connective tissue (supporting tissue that surrounds other tissues and organs).
Stromal cellsNon-blood cells derived from blood organs, such as bone marrow or fetal liver, which are capable of supporting growth of blood cells in vitro.
Strong ForceThe interaction responsible for binding quarks, antiquarks, and gluons to make hadrons. Residual strong interactions provide the nuclear binding force.
structural chemical analysisThe composition of biomass reported by the proportions of the major structural components; cellulose, hemicellulose, and lignin.
Structural firesFire originating in and burning any part or all of any building, shelter, or other structure.
structural geneA gene that encodes a polypeptide, with either enzymatic or structural functions, and that is required for the normal metabolism and growth of a cell or…
Structural genomicsThe effort to determine the 3D structures of large numbers of proteins using both experimental techniques and computer simulation
Structural HeightDistance between the lowest point in the excavated foundation (excluding narrow fault zones) and the top of dam.
StructureChanges in the shape of the bottom of lakes, rivers, or impoundments, especially those that influence fish behavior.
Structure-functionalismThe scientific tradition that stresses the relationship between a physical structure and its function, for example, the related disciplines of anatomy and…
StudA popular term used for a length of wood or steel used in or for wall framing.
Stumpage(1) Standing live or dead uncut trees. (2) The value or rate paid to purchase standing trees for harvest.
styleSlender column of tissue that arises from the top of the ovary and terminates in the stigma, and through which the pollen tube must grow to achieve…
Sub-canopiesWoody vegetation that grows beneath the canopy or tree tops of a forest or woodland.
sub-cloneA procedure in which a large cloned DNA molecule is divided into smaller fragments, each one of which is then separately cloned.
sub-cultureDivision and transfer of a portion of a culture to fresh medium. Sometimes used to denote the adding of fresh liquid to a suspension culture.
sub-culture numberThe number of times cells, etc., have been sub-cultured..
Sub-organizationAny organization such as agencies, departments, offices, or local jurisdictions having a supportive role in emergency planning and preparedness.
sub-strainDerived from a strain by the isolation of an individual or group of individuals having properties or markers not shared by the strain as a whole.
sub-unit vaccineOne or more immunogenic protein s, either purified from the pathogen itself or produced from a cloned pathogen gene.
SubalpineThe upper mountain vegetation immediately below the cold limits of tree and tall shrub growth.
SubbaseA layer used in a pavement system between the subgrade and base course, or between the subgrade and portland cement concrete pavement.
Subbituminous coalA dull, black coal of rank intermediate between lignite and bituminous coal. See coal.
SubcloningThe process of tranferring a cloned DNA fragment from one vector to another. (See Cloning.)
Subcritical flowThose conditions of flow for which the depths are greater than critical and the velocities are less than critical.
SubculturingTransferring cultured cells, with or without dilution, from one culture vessel to another.
SubdivisionA subdivision occurs as the result of dividing land into lots for sale or development.
Subdivision Rules and RegulationsProcedures, requirements, and provisions governing the subdivision of land that is specified in formal Rules and Regulations promulgated by a city or town…
SubdrainageA land area (basin) bounded by ridges or similar topographic features, encompassing only part of a watershed.
SubdrillingOverdrilling or drilling below final grade. Sometimes necessary to assure that final grade is obtained when blasting.
subgenomic promoterA promoter added to a virus for a specific heterologous gene, resulting in the formation of mRNA for that gene alone.
SubgradeSoil prepared and compacted to support a structure or pavement system.
Subgrade surfaceThe surface of the earth or rock prepared to support a structure or a pavement system.
SubirrigationApplying irrigation water below the ground surface either by raising the water table within or near the root zone, or by use of a buried perforated or…
SublimationThe transition of a substance from the solid phase directly to the vapor phase, or vice versa, without passing through an intermediate liquid phase.
Sublimation of iceThe transition of water from solid to gas without passing through the liquid phase.
Submerged aquatic vegetation (SAV)Aquatic vegetation, such as sea grasses, that cannot withstand excessive drying and therefore live with their leaves at or below the water surface.
SubrefractionThe bending of the radar beam in the vertical which is less than under standard refractive conditions.
SubsidenceSinking or settlement of the land surface, due to any of several processes. As commonly used, the term relates to the vertical downward movement of…
Subsidence InversionA temperature inversion that develops aloft as a result of air gradually sinking over a wide area and being warmed by adiabatic compression, usually…
SubsistenceThe practices by which a group or individual acquires food, such as through hunting and gathering, fishing, and agriculture.
subspeciesPopulation(s) of organisms sharing certain characteristics that are not present in other populations of the same species.
SubstationAn electrical installation containing power conversion (and sometimes generation) equipment, such as transformers, compensators, and circuit breakers.
Substation capacityThe substation capacities are given in kVA (kilovolt-amperes). To determine the load in kilowatts, which could be served from the transformers, the…
substitutionReplacement of one nucleotide in a DNA sequence by another nucleotide or replacement of one amino acid in a protein by another amino acid.
Substrate1. A compound that is altered by an enzyme. 2. Food source for growing cells or micro-organisms. 3. Material on which a sedentary organism lives and grows.
Subsurface Storm FlowThe lateral motion of water through the upper layers until it enters a stream channel. This usually takes longer to reach stream channels than runoff.
SubtidalA marine or estuarine environment that lies below mean low water; always (or almost always) submerged in a tidally-influenced area.
Subtle Heavy Rainfall SignatureThis heavy rain signature is often difficult to detect on satellite. These warm top thunderstorms are often embedded in a synoptic-scale cyclonic…
Subtropical CycloneA non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones.
Subtropical DepressionA subtropical cyclone in which the maximum 1-minute sustained surface wind is 33 knots (38 mph) or less.
Subtropical Jet(Abbrev. STJ) - this jet stream is usually found between 20° and 30° latitude at altitudes between 12 and 14 km.
Subtropical StormA subtropical cyclone in which the maximum 1-minute sustained surface wind is 34 knots (39 mph) or more.
Subunit vaccineA vaccine composed of a purified antigenic determinant that is separated from the virulent organism. (See Vaccine, Enzyme.)
SuccessionA series of dynamic changes by which one group of organisms succeeds another through stages leading to potential natural community or climax.
suckerA shoot that arises from an underground root or stem. Of particular significance to grafted plants, since the sucker will be genotypically rootstock…
suckeringType of vegetative propagation where lateral buds grow out to produce an individual that is a clone of the parent.
Suction VortexA small but very intense vortex within a tornado circulation. Several suction vortices typically are present in a multiple-vortex tornado.
Sudden Commencement (SC)In solar-terrestrial terms, an abrupt increase or decrease in the northward component of the geomagnetic field, which marks the beginning of a geomagnetic…
Sudden Impulse (SI+ or SI-)In solar-terrestrial terms, a sudden perturbation of several gammas in the northward component of the low-latitude geomagnetic field, not associated with…
Sudden Ionospheric Disturbance (SID)In solar-terrestrial terms, HF propagation anomalies due to ionospheric changes resulting from solar flares, proton events and geomagnetic storms.
suicide geneA strategy for making cancer cells more vulnerable to chemotherapy. One approach has been to link parts of genes expressed in cancer cells to other genes…
Sulfate AerosolsParticulate matter that consists of compounds of sulfur formed by the interaction of sulfur dioxide and sulfur trioxide with other compounds in the…
Sulfate attackDamage to concrete caused by the effects of a chemical reaction between sulfates in soils or ground water and hydrated lime and hydrated calcium aluminate…
Sulfated proteoglycanMolecules found primarily in connective tissues and joint fluids and that provide lubrication.
Sulfur cycleCyclic movement of sulfur in different chemical forms from the environment, to organisms, and then back to the environment.
Sulfur dioxide (SO<sub>2</sub>)A compound composed of one sulfur and two oxygen molecules. Sulfur dioxide emitted into the atmosphere through natural and anthropogenic processes is…