Semi-aridModerately dry region or climate where moisture is normally greater than under arid conditions but still definitely limits the production of vegetation.
semi-conservative replicationDuring DNA duplication, each strand of a parent DNA molecule acts as a template for the synthesis of a new complementary strand.
semi-continuous cultureCells in an actively dividing state which are maintained in culture by periodically draining off the medium and replenishing it with fresh medium.
semi-permeable membraneA natural or synthetic material which selectively allows the passage of certain ions or molecules.
semi-sterilityThe condition of partial fertility. Often associated with chromosomal aberrations or the result of mutagenesis.
SemiconductorAny material that has a limited capacity for conducting an electric current. Certain semiconductors, including silicon, gallium arsenide, copper indium…
Semiconservative replicationDuring DNA duplication, each strand of a parent DNA molecule is a template for the synthesis of its new complementary strand.
Semipermanent anticycloneSemipermanent anticyclone (high) High pressure area largely predominate during a major portion of the year where an anticyclone appears on the mean…
Sending DistrictAn overlay zoning district established by the Town Meeting/Town Council upon recommendation from the Planning Board as an area in which use or development…
Sendout(Natural Gas) Volume of natural gas that is re-gasified and delivered into the downstream natural gas grid from an LNG terminal.
senescenceA late stage in the development of multicellular organisms, during which irreversible loss of function and degradation of biological components occur.
Senior water rightsWater rights that have been established first (measured by the date of appropriation) to the limit of their respective right, frequently to the exclusion…
sense RNAThe RNA transcript of the coding strand DNA (often represented as the (+)-strand). Opposite: antisense RNA.
Sensible Cooling EffectThe difference between the total cooling effect and the dehumidifying effect.
Sensible Cooling LoadThe interior heat gain due to heat conduction, convection, and radiation from the exterior into the interior, and from occupants and appliances.
Sensible HeatThe heat absorbed or released when a substance undergoes a change in temperature.
Sensible Heat FluxThe flux of heat from the earth's surface to the atmosphere that is not associated with phase changes of water; a component of the surface energy budget.
Sensible Heat StorageA heat storage system that uses a heat storage medium, and where the additional or removal of heat results in a change in temperature.
SensitivityWhen referring to a medical test, sensitivity refers to the percentage of people who test positive for a specific disease among a group of people who have…
Sensitivity level (analysis)Measures (e.g., high, medium, and low) of public concern for the maintenance of scenic quality.
Separation depositSand deposit located at the upstream end of a recirculation zone, where downstream flow becomes separated from the channel bank.
Separation EddyAn eddy that forms near the ground on the windward or leeward side of a bluff object or steeply rising hillside; streamlines above this eddy go over the…
sepsis(SEP-sis) The presence of bacteria or their toxins in the blood or tissues.
septate(SEP-tate) An organ or structure that is divided into compartments.
Septic tankUnderground tank for treatment of wastewater from a home in rural and suburban areas.
septumA dividing wall or partition, which splits a structure into separate cells or compartments.
sequenceThe linear order of nucleotides along a DNA or RNA molecule, and the process of obtaining this.
Sequence assemblyA process whereby the order of multiple sequenced DNA fragments is determined.
sequence characterized amplified region(Abbreviation: SCAR). A molecular marker obtained by the conversion to a sequence-tagged site of a single random amplified polymorphic DNA product.
sequence divergenceThe percent difference in the nucleotide sequence between related nucleic acid sequences, or in the amino acid sequence in a comparison between related…
Sequence hypothesisFrancis Crick's seminal concept that genetic information exists as a linear DNA code; DNA and protein sequence are colinear.
Sequence tagged site (STS)A unique (single-copy) DNA sequence used as a mapping landmark on a chromosome.
sequence-tagged site(Abbreviation: STS). Short unique DNA sequence (200-500 bp long) that can be amplified by PCR and is thus tagged to the site on the chromosome from which…
SequencingDetermination of the order of nucleotides (base sequences) in a DNA or RNA molecule or the order of amino acids in a protein.
Sequencing technologyThe instrumentation and procedures used to determine the order of nucleotides in DNA.
Seral stagesThe series of relatively transitory plant communities that develop during ecological succession from bare ground to the climax stage.
Serial DerechoType of derecho that consists of an extensive squall line which is oriented such that the angle between the mean wind direction and the squall line axis…
serial divisionSplitting of excised shoot-tip material growing in vitro, in order to induce the development of greater numbers of plantlets.
serial float cultureA technique whereby immature anthers are floated on a liquid medium, and continue their development through to the release of pollen.
seriesA configuration of an electrical circuit in which the positive lead is connected to the negative lead of another energy producing, conducting, or…
Series ConnectionA way of joining photovoltaic cells by connecting positive leads to negative leads; such a configuration increases the voltage.
Series ResistanceParasitic resistance to current flow in a cell due to mechanisms such as resistance from the bulk of the semiconductor material, metallic contacts, and…
SerologyThe branch of science dealing with the measurement and characterization of antibodies and other immunological substances in body fluids, particularly…
serumThe clear liquid part of the blood that remains after blood cells and clotting proteins have been removed.
serum albuminThe main protein in blood plasma. Low levels of serum albumin occur in people with malnutrition, inflammation, and serious liver and kidney disease.
Service spillway (primary spillway)A structure located on or adjacent to a storage or detention dam over or through which surplus or floodwaters which cannot be contained in the allotted…
Servo LoopIn radar meteorology, a generic description of hardware needed to remotely control the motion of the antenna dish.
SetThree of a kind when you have two of the rank in your hand, and there is one on the board.
Set-upThe process whereby strong winds blowing down the length of a lake cause water to "pile up" at the downwind end, raising water levels there and lowering…
Setback ThermostatA thermostat that can be set to automatically lower temperatures in an unoccupied house and raise them again before the occupant returns.
SettlementAfter negotiating, the amount you agree to accept from the insurance company as full payment for your loss.
SetupThis referes to various adjustments that are made to the race car's suspension for handling at a specific racetrack.
severe combined immunodeficiency (SCID)A disease affecting the immune system. SCID is fatal if affected individuals do not receive bone marrow transplants. See also antibody
Severe IcingThe rate of ice accumulation on an aircraft is such that de-icing/anti-icing equipment fails to reduce or control the hazard.
Severe Local StormA convective storm that usually covers a relatively small geographic area, or moves in a narrow path, and is sufficiently intense to threaten life and/or…
Severe Local Storm WatchAn alert issued by the National Weather Service for the contiguous U.S. and its adjacent waters of the potential for severe thunderstorms or tornadoes.
Severe ThunderstormA thunderstorm that produces a tornado, winds of at least 58 mph (50 knots), and/or hail at least ¾" in diameter.
Severe Thunderstorm WarningThis is issued when either a severe thunderstorm is indicated by the WSR-88D radar or a spotter reports a thunderstorm producing hail 3/4 inch or larger…
Severe Thunderstorm WatchThis is issued by the National Weather Service when conditions are favorable for the development of severe thunderstorms in and close to the watch area.
Severe Weather AnalysisThis WSR-88D radar product provides 3 base products (reflectivity (SWR), radial velocity (SWV), and spectrum width (SWW)) at the highest resolution…
Severe Weather Potential StatementThis statement is designed to alert the public and state/local agencies to the potential for severe weather up to 24 hours in advance.
Severe Weather ProbabilityThis WSR-88D radar product algorithm displays numerical values proportional to the probability that a storm will produce severe weather within 30 minutes.
Severe Weather StatementA National Weather Service product which provides follow up information on severe weather conditions (severe thunderstorm or tornadoes) which have…
SewageThe waste water from domestic, commercial and industrial sources carried by sewers.
sewage treatmentA widespread biotechnological processes in developed economies. Methods vary widely, but all are designed for the biological break-down of human and…
Sewage treatment (primary)Mechanical treatment of sewage in which large solids are filtered out by screens and suspended solids settle out as sludge in a sedimentation tank.
Sewer tileGlazed waterproof clay pipe with bell joints.
sex chromosomeDifferentiated chromosome which is responsible for the determination of sex of the individual.
sex determinationAny method by which the distinction between males and females is established in a species, particularly at an early stage of foetal development.
sex ductionThe incorporation of bacterial genes into F factors and their subsequent transfer, by conjugation, to a recipient cell.
sex factorA bacterial episome (e.g. the F plasmid in E. coli ) that enables the cell to be a donor of genetic material.
sex hormonesSteroid hormones that control sexual development in animals.
sex linkageReferring to genes present on one of the sex chromosomes, thus genetically linked to the sex of the individual.
sex-influenced dominanceThe tendency for gene action to vary between the sexes within a species. For example, the presence of horns in some breeds of sheep appears to be dominant…
sex-limitedExpression of a trait in only one sex; e.g. milk production in mammals; egg production in chickens.
Sex-linkedLocated on the X chromosome. Sex-linked (or x-linked) diseases are generally seen only in males. See also gene, mutation
Shading CoefficientA measure of window glazing performance that is the ratio of the total solar heat gain through a specific window to the total solar heat gain through a…
Shadow PersonA commonly-reported inky black humanoid entity that moves fast, it is often spotted out of the corner of the eye and has been interpreted to be anything…
Shadow zoneThe region where direct sound does not penetrate because of upward diffraction due to vertical temperature and/or wind gradients.
ShaftThe vertical segment of a column or pilaster between the base and the capital.
Shaft horsepowerA measure of the actual mechanical energy per unit time delivered to a turning shaft. 1 shaft horsepower = 1 electric horsepower = 550 ft-lb/second.