Department of Embryology, Obstetrics, andGynecology University of BolognaBologna, Italy Clayton Harris Associate ProfessorDepartment of Geography and GeologyMiddle Tennessee State Univer
Trang 1The GALE ENCYCLOPEDIA
THIRD EDITION
Trang 2This page intentionally left blank
Trang 3The GALEENCYCLOPEDIA
Trang 4Gale Encyclopedia of Science, Third Edition
K Lee Lerner and Brenda Wilmoth Lerner, Editors
Project Editor
Kimberley A McGrath
Editorial
Deirdre S Blanchfield, Chris Jeryan, Jacqueline
Longe, Mark Springer
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© 2004 by Gale Gale is an imprint of The Gale
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LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA
Gale encyclopedia of science / K Lee Lerner & Brenda Wilmoth Lerner, editors.— 3rd ed.
p cm.
Includes index.
ISBN 0-7876-7554-7 (set) — ISBN 0-7876-7555-5 (v 1) — ISBN 0-7876-7556-3 (v 2) — ISBN 0-7876-7557-1 (v 3) — ISBN 0-7876-7558-X (v 4) — ISBN 0-7876-7559-8 (v 5) — ISBN 0-7876-7560-1 (v 6)
1 Science—Encyclopedias I Lerner, K Lee II Lerner, Brenda Wilmoth.
Trang 5Topic List vii
Organization of the Encyclopedia xxvii
Advisory Board xxix
Contributors xxxi
Entries Volume 1 (Aardvark–Chaos) 1–818 Volume 2 (Charge-coupled device–Eye) 819–1572 Volume 3 (Factor–Kuru) 1573–2254 Volume 4 (Lacewings–Pharmacogenetics) 2255–3036 Volume 5 (Pheasants–Star) 3037–3800 Volume 6 (Star cluster–Zooplankton) 3801–4378
General Index 4379–4495
Trang 6This page intentionally left blank
Trang 7AluminumAluminum hydroxideAlzheimer diseaseAmaranth family (Amaranthaceae)Amaryllis family (Amaryllidaceae)American Standard Code forInformation InterchangeAmes test
Amicable numbersAmides
Amino acidAmmoniaAmmonificationAmnesiaAmniocentesisAmoebaAmphetaminesAmphibiansAmplifierAmputationAnabolismAnaerobicAnalemmaAnalgesiaAnalog signals and digital signalsAnalytic geometry
AnaphylaxisAnatomyAnatomy, comparativeAnchovy
Anemia
AdrenalsAerobicAerodynamicsAerosolsAfricaAge of the universeAgent OrangeAging and deathAgouti
Agricultural machinesAgrochemicalsAgronomyAIDSAIDS therapies and vaccinesAir masses and frontsAir pollution
AircraftAirshipAlbatrossesAlbedoAlbinismAlchemyAlcoholAlcoholismAldehydesAlgaeAlgebraAlgorithmAlkali metalsAlkaline earth metalsAlkaloid
Alkyl groupAllelesAllergyAllotropeAlloy
TOPIC LIST
Trang 8Atomic modelsAtomic numberAtomic spectroscopyAtomic theoryAtomic weightAtomsAttention-deficit/Hyperactivitydisorder (ADHD)
AuksAustraliaAutismAutoimmune disordersAutomatic pilotAutomationAutomobileAutotrophAvogadro’s numberAye-ayes
B
BabblersBaboonsBacteriaBacteriophageBadgersBall bearingBallistic missilesBallisticsBalloonBananaBandicootsBar codeBarberryBarbetsBarbituratesBariatricsBariumBarium sulfateBark
BarleyBarnaclesBarometerBarracuda
ArcARC LAMPArchaebacteriaArchaeoastronomyArchaeogeneticsArchaeologyArchaeometallurgyArchaeometryArcheological mappingArcheological sitesArithmeticArmadillosArrow wormsArrowgrassArrowrootArteriesArteriosclerosisArthritisArthropodsArthroscopic surgeryArtifacts and artifact classificationArtificial fibers
Artificial heart and heart valveArtificial intelligence
Artificial visionArum family (Araceae)Asbestos
Asexual reproductionAsia
Assembly lineAsses
Associative propertyAsteroid 2002AA29AsthenosphereAsthmaAstrobiologyAstroblemesAstrolabeAstrometryAstronomical unitAstronomyAstrophysicsAtmosphere, composition andstructure
Atmosphere observation Atmospheric circulationAtmospheric optical phenomenaAtmospheric pressure
Trang 9Brown dwarfBrownian motionBrucellosisBryophyteBubonic plagueBuckminsterfullereneBuckthorn
BuckwheatBuds and buddingBuffer
Building design/architectureBulbuls
Bunsen burnerBuoyancy, principle ofBuret
BurnBustardsButtercupButterfliesButterfly fishButyl groupButylated hydroxyanisoleButylated hydroxytolueneBuzzards
C
CactusCAD/CAM/CIMCaddisfliesCaeciliansCaffeineCaissonCalciumCalcium carbonateCalcium oxideCalcium propionateCalcium sulfateCalculatorCalculusCalendars
BioremediationBiosphereBiosphere ProjectBiotechnologyBioterrorismBirch family (Betulaceae)Birds
Birds of paradiseBirds of preyBirthBirth defectsBisonBitternsBivalves
BL Lacertae objectBlack holeBlackbirdsBlackbody radiationBleach
BlenniesBlindness and visual impairmentsBlindsnakes
BloodBlood gas analysisBlood supplyBlotting analysisBlue revolution (aquaculture)Bluebirds
BoarfishBoasBohr ModelBoiling pointBond energyBony fishBoobies and gannetsBoolean algebraBoric acidBotanyBotulismBowen’s reaction seriesBowerbirds
BowfinBoxfishBrachiopodsBrackishBrainBrewingBrick
Trang 10ChlorineChlorofluorocarbons (CFCs)Chloroform
ChlorophyllChloroplastCholeraCholesterolChordatesChorionic villus sampling (CVS)Chromatin
ChromatographyChromosomal abnormalitiesChromosome
Chromosome mappingCicadas
Cigarette smokeCircle
Circulatory systemCircumscribed and inscribedCirrhosis
Citric acidCitrus treesCivetsClimax (ecological)Clingfish
Clone and cloningClosed curvesClosure propertyClouds
Club mossesCoalCoast and beachCoatis
CocaCocaineCockatoosCockroachesCodeineCodfishesCodonsCoefficientCoelacanth
CatfishCathetersCathodeCathode ray tubeCation
CatsCattailsCattle family (Bovidae)Cauterization
CaveCave fishCelestial coordinatesCelestial mechanicsCelestial sphere: The apparentmotions of the Sun, Moon,planets, and stars
CellCell deathCell divisionCell, electrochemical Cell membrane transportCell staining
Cellular respirationCellular telephoneCellulose
CentipedesCentrifugeCeramicsCerenkov effectCetaceansChachalacasChameleonsChaosCharge-coupled deviceChelate
Chemical bondChemical evolutionChemical oxygen demandChemical reactionsChemical warfareChemistryChemoreceptionChestnutChi-square testChickenpoxChildhood diseasesChimaeras
Chimpanzees
Trang 11CrystalCubic equationsCuckoosCurareCurlewsCurrentsCurveCushing syndromeCuttlefish
CyberneticsCycadsCyclamateCyclone and anticycloneCyclosporine
CyclotronCystic fibrosisCytochromeCytology
D
DamsDamselfliesDark matterDating techniquesDDT (Dichlorodiphenyl-trichloroacetic acid)Deafness and inherited hearing lossDecimal fraction
DecompositionDeer
Deer mouseDeforestationDegreeDehydroepiandrosterone (DHEA)Delta
DementiaDengue feverDenitrification
ConstellationConstructionsContaminated soilContaminationContinentContinental driftContinental marginContinental shelfContinuityContour plowingContraceptionConvectionCoordination compoundCopepods
CopperCoral and coral reefCoriolis effectCork
CormCormorantsCorn (maize)Coronal ejections and magneticstorms
Correlation (geology)Correlation (mathematics)Corrosion
Cosmic background radiationCosmic ray
CosmologyCotingasCottonCoulombCountableCoursers and pratincolesCourtship
CoypuCrabsCraneCranesCrayfishCrestfishCreutzfeldt-Jakob diseaseCrickets
Critical habitatCrocodilesCrop rotationCropsCross multiply
Trang 12EcosystemEcotoneEcotourismEdemaEel grass
El Niño and La NiñaEland
Elapid snakesElasticityElectric arcElectric chargeElectric circuitElectric conductorElectric currentElectric motorElectric vehiclesElectrical conductivityElectrical power supplyElectrical resistanceElectricity
Electrocardiogram (ECG)Electroencephalogram (EEG)Electrolysis
ElectrolyteElectromagnetic fieldElectromagnetic inductionElectromagnetic spectrumElectromagnetismElectromotive forceElectron
Electron cloudElectronicsElectrophoresisElectrostatic devicesElement, chemicalElement, families ofElement, transuraniumElements, formation ofElephant
Elephant shrews
DobsonfliesDogwood treeDomainDonkeysDopamineDoppler effectDoriesDormouseDouble-blind studyDouble helix Down syndromeDragonfliesDrift netDrongos
Drosophila melanogaster
DroughtDucksDuckweedDuikersDuneDuplication of the cubeDust devil
DVDDwarf antelopesDyes and pigmentsDysentery
DyslexiaDysplasiaDystrophinopathies
E
e (number)EaglesEarEarthEarth scienceEarth’s interiorEarth’s magnetic fieldEarth’s rotationEarthquakeEarwigsEating disordersEbola virusEbonyEchiuroid worms
Trang 13Elephant snout fish
Figurative numbersFiltration
FinchesFirsFishFlagellaFlame analysisFlamingosFlatfishFlatwormsFlaxFleasFliesFlightless birdsFloodingFloraFlowerFluid dynamicsFluid mechanicsFluorescenceFluorescence in situ hybridization(FISH)
Fluorescent lightFluoridationFlying fishFocused Ion Beam (FIB)Fog
FoldFood chain/webFood irradiationFood poisoningFood preservationFood pyramidFoot and mouth diseaseForce
Forensic scienceForestryForestsFormula, chemical
EthnoarchaeologyEthnobotanyEthyl groupEthylene glycolEthylenediaminetetra-acetic acidEtiology
EubacteriaEugenicsEukaryotaeEuropeEutrophicationEvaporationEvapotranspirationEven and oddEvent horizonEvolutionEvolution, convergentEvolution, divergentEvolution, evidence ofEvolution, parallelEvolutionary change, rate ofEvolutionary mechanismsExcavation methodsExclusion principle, PauliExcretory systemExercise
Exocrine glandsExplosivesExponentExtinctionExtrasolar planetsEye
F
FactorFactorialFalconsFaraday effectFat
Fatty acidsFaultFaunaFax machineFeather starsFermentation
Trang 14Grand unified theoryGrapes
Graphs and graphingGrasses
GrasshoppersGrasslandsGravitational lensGravity and gravitationGreat Barrier ReefGreatest common factorGrebes
Greenhouse effectGroundhogGroundwaterGroupGrouseGrowth and decayGrowth hormonesGuenons
Guillain-Barre syndromeGuinea fowl
Guinea pigs and caviesGulls
GuppyGutenberg discontinuityGutta percha
GymnospermGynecologyGyroscope
H
HabitatHagfishHalf-lifeHalide, organicHall effect
Genetic disordersGenetic engineeringGenetic identification ofmicroorganismsGenetic testingGenetically modified foods andorganisms
GeneticsGenetsGenomeGenomics (comparative)Genotype and phenotypeGeocentric theoryGeochemical analysisGeochemistryGeodeGeodesicGeodesic domeGeographic and magnetic polesGeologic map
Geologic timeGeologyGeometryGeomicrobiologyGeophysicsGeotropismGerbilsGerm cells and the germ cell lineGerm theory
GerminationGerontologyGesneriasGeyserGibbons and siamangsGila monster
GingerGinkgoGinsengGiraffes and okapiGIS
GlaciersGlandsGlassGlobal climateGlobal Positioning SystemGlobal warming
GlycerolGlycol
Trang 15IbisesIceIce age refugesIce agesIcebergsIcemanIdentity elementIdentity propertyIgneous rocksIguanasImaginary numberImmune systemImmunologyImpact craterImprinting
In vitro fertilization (IVF)
In vitro and in vivo
Incandescent lightIncinerationIndicator, acid-base Indicator speciesIndividualIndoor air qualityIndustrial mineralsIndustrial RevolutionInequality
Inertial guidanceInfectionInfertilityInfinityInflammationInflection pointInfluenzaInfrared astronomyInherited disordersInsecticidesInsectivore
HistamineHistorical geologyHoatzin
Hodgkin’s diseaseHolly family (Aquifoliaceae)Hologram and holographyHomeostasis
HoneycreepersHoneyeatersHoopoeHorizonHormonesHornbillsHorse chestnutHorsehair wormsHorses
Horseshoe crabsHorsetailsHorticultureHot spotHovercraftHubble Space TelescopeHuman artificial chromosomesHuman chorionic gonadotropinHuman cloning
Human ecologyHuman evolutionHuman Genome ProjectHumidity
HummingbirdsHumusHuntington diseaseHybrid
HydraHydrocarbonHydrocephalusHydrochlorofluorocarbonsHydrofoil
HydrogenHydrogen chlorideHydrogen peroxideHydrogenationHydrologic cycleHydrologyHydrolysisHydroponicsHydrosphereHydrothermal vents
Trang 16Internal combustion engine
International Space Station
International Ultraviolet Explorer
Internet file transfer and tracking
Internet and the World Wide Web
LEDLegionnaires’ diseaseLegumes
LemmingsLemursLensLeprosyLeukemiaLewis structureLice
LichensLife historyLigandLightLight-yearLightningLilacLily family (Liliaceae)Limit
Limiting factorLimpetsLine, equations ofLinear algebraLipid
Liquid crystalsLithiumLithographyLithosphereLithotripsyLiverwortLivestockLobstersLockLock and keyLocusLogarithmsLoonsLORAN
Jet streamJuniperJupiter
K
K-T event (Cretaceous-Tertiaryevent)
Kangaroo ratsKangaroos and wallabiesKarst topographyKaryotype and karyotype analysisKelp forests
Kepler’s lawsKeystone speciesKillifish
KingfishersKingletsKoalasKolaKorsakoff’s syndromeKrebs cycle
Kuiper belt objectsKuru
L
LacewingsLactic acidLagomorphsLakeLamarckismLampreys and hagfishesLand and sea breezesLand use
LandfillLandformLangurs and leaf monkeysLantern fish
LanthanidesLarksLaryngitisLaserLaser surgeryLatitude and longitude
Trang 17MildewMilkweedsMilky WayMiller-Urey ExperimentMillipedes
MimicryMineralogyMineralsMiningMinkMinnowsMinor planetsMint familyMir Space StationMirrors
MiscibilityMistletoeMitesMitosisMixture, chemicalMöbius stripMockingbirds and thrashersMode
Modular arithmeticMohs’ scaleMoldMoleMole-ratsMolecular biologyMolecular formulaMolecular geometryMolecular weightMoleculeMolesMollusksMomentumMonarch flycatchersMongooses
Monitor lizardsMonkeys
MarsupialsMarten, sable, and fisherMaser
MassMass extinctionMass numberMass productionMass spectrometryMass transportationMass wastingMathematicsMatrixMatterMaunder minimumMaxima and minimaMayflies
MeanMedianMedical geneticsMeiosis
MembraneMemoryMendelian geneticsMeningitis
MenopauseMenstrual cycleMercurous chlorideMercury (element)Mercury (planet)Mesoscopic systemsMesozoa
Metabolic disordersMetabolismMetalMetal fatigueMetal productionMetallurgyMetamorphic gradeMetamorphic rockMetamorphismMetamorphosisMeteorologyMeteors and meteoritesMethyl group
Metric systemMice
Michelson-Morley experimentMicrobial genetics
Trang 18Mulberry family (Moraceae)
Multiple personality disorder
Number theoryNumeration systemsNut
NuthatchesNutmegNutrient deficiency diseasesNutrients
NutritionNux vomica tree
O
OaksObesityObsessionOceanOcean basinOcean sunfishOcean zonesOceanographyOctet ruleOctopusOhm’s lawOil spillsOil well drillingOld-growth forestsOlive family (Oleaceae)Omnivore
One-to-one correspondenceOpah
Open-source softwareOpossums
Opportunistic speciesOptical data storageOptics
Orang-utanOrbitOrchid familyOrdinal numberOre
OrganOrganelles and subcellular genetics
Natural gasNatural numbersNautical archaeologyNEAR-Earth Object Hazard IndexNectar
NegativeNeptuneNerve growth factorNerve impulses and conduction ofimpulses
Nervous systemNeuromuscular diseasesNeuron
NeuroscienceNeurosurgeryNeurotransmitterNeutralizationNeutrinoNeutronNeutron activation analysisNeutron star
New World monkeysNewton’s laws of motionNewts
NicheNicotineNight vision enhancement devicesNightshade
Nitric acidNitrificationNitrogenNitrogen cycleNitrogen fixationNoise pollutionNon-Euclidean geometryNon-point sourceNonmetalNorth AmericaNova
NovocainNuclear fissionNuclear fusionNuclear magnetic resonanceNuclear medicine
Nuclear powerNuclear reactorNuclear weaponsNuclear winter
Trang 19PhotochemistryPhotocopyingPhotoelectric cellPhotoelectric effectPhotographyPhotography, electronicPhoton
PhotosynthesisPhototropismPhotovoltaic cellPhylogenyPhysical therapyPhysics
PhysiologyPhysiology, comparativePhytoplankton
PiPigeons and dovesPigs
PikePiltdown hoaxPinecone fishPinesPipefishPlaceboPlanck’s constantPlane
Plane familyPlanetPlanet XPlanetary atmospheresPlanetary geologyPlanetary nebulaePlanetary ring systems
PandasPangolinsPapayaPaperParabolaParallaxParallelParallelogramParasitesParityParkinson diseaseParrots
ParthenogenesisParticle detectorsPartridgesPascal’s trianglePassion flowerPaternity and parentage testingPathogens
PathologyPCRPeafowlPeanut wormsPeccariesPedigree analysisPelicans
PenguinsPeninsulaPentyl groupPeonyPepperPeptide linkagePercentPerceptionPerchPeregrine falconPerfect numbersPeriodic functionsPeriodic tablePermafrostPerpendicularPesticidesPestsPetrels and shearwatersPetroglyphs and pictographsPetroleum
pHPhalangers
Trang 20Potassium aluminum sulfate
Potassium hydrogen tartrate
Quantum numberQuarks
QuasarQuetzalQuinine
R
RabiesRaccoonsRadarRadial keratotomyRadiation
Radiation detectorsRadiation exposureRadical (atomic)Radical (math)Radio
Radio astronomyRadio wavesRadioactive datingRadioactive decayRadioactive falloutRadioactive pollutionRadioactive tracersRadioactive wasteRadioisotopes in medicineRadiology
RadonRailsRainbowsRainforestRandomRangelandRaptorsRare gasesRare genotype advantage
Prairie dogPrairie falconPraying mantisPrecession of the equinoxesPrecious metals
PrecipitationPredatorPrenatal surgeryPrescribed burnPressurePreyPrimatesPrime numbersPrimrosesPrintingPrionsPrismProbability theoryProboscis monkeyProjective geometryProkaryote
PronghornProofPropyl groupProsimiansProstheticsProteasProtected areaProteinsProteomicsProtistaProtonProtozoaPsychiatryPsychoanalysisPsychologyPsychometryPsychosisPsychosurgeryPubertyPuffbirdsPuffer fishPulsarPunctuated equilibriumPyramid
Pythagorean theoremPythons
Trang 21SealsSeamountsSeasonal windsSeasonsSecondary pollutantsSecretary birdSedgesSediment and sedimentationSedimentary environmentSedimentary rockSeed fernsSeedsSegmented wormsSeismographSelectionSequencesSequencingSequoiaServomechanismsSesame
Set theorySETISevere acute respiratory syndrome(SARS)
Sewage treatmentSewing machineSex changeSextant
Ribonucleic acid (RNA)Ribosomes
RiceRicinRickettsiaRiversRNA functionRNA splicingRobinsRoboticsRockets and missilesRocks
RodentsRollersRoot systemRose family (Rosaceae)Rotation
RoundwormsRuminationRushesRusts and smuts
S
Saiga antelopeSalamandersSalmonSalmonellaSaltSaltwaterSampleSandSand dollarsSandfishSandpipersSapodilla treeSardinesSarin gasSatelliteSaturnSavannaSavantSawfishSaxifrage familyScalar
Scale insects
Trang 22StarStar clusterStar formationStarburst galaxyStarfish
StarlingsStates of matterStatistical mechanicsStatistics
Steady-state theorySteam engineSteam pressure sterilizerStearic acid
SteelStellar evolutionStellar magnetic fieldsStellar magnitudesStellar populationsStellar structureStellar windStem cellsStereochemistrySticklebacksStilts and avocetsStimulus
Stone and masonryStoneflies
StorksStormStorm surgeStrataStratigraphyStratigraphy (archeology)Stream capacity and competenceStream valleys, channels, andfloodplains
StrepsipteraStressStress, ecologicalString theory
Solar activity cycleSolar flare
Solar illumination: Seasonal anddiurnal patterns
Solar prominenceSolar systemSolar windSolder and soldering ironSolstice
SolubilitySolutionSolution of equationSonar
Song birdsSonoluminescenceSorghum
Sound wavesSouth AmericaSoybeanSpaceSpace probeSpace shuttleSpacecraft, mannedSparrows and buntingsSpecies
Spectral classification of starsSpectral lines
SpectroscopeSpectroscopySpectrumSpeechSphereSpider monkeysSpiderwort familySpin of subatomic particlesSpina bifida
SpinachSpiny anteatersSpiny eelsSpiny-headed wormsSpiral
SpirometerSplit-brain functioningSponges
Spontaneous generationSpore
SpringtailsSpruce
Trang 23Swallows and martins
Swamp cypress family
TouchTowers of HanoiToxic shock syndromeToxicology
Trace elementsTragopansTrains and railroadsTranquilizersTranscendental numbersTransducer
TransformerTransgenicsTransistorTransitiveTranslationsTranspirationTransplant, surgicalTrapezoid
TreeTree shrewsTrichinosisTriggerfishTriglyceridesTrigonometryTritiumTrogonsTrophic levelsTropic birdsTropical cycloneTropical diseasesTrout-perchTrue bugs
T
T cellsTanagersTaphonomyTapirsTarponsTarsiersTartaric acidTasmanian devilTaste
TaxonomyTay-Sachs diseaseTea plant
TectonicsTelegraphTelemetryTelephoneTelescopeTelevisionTemperatureTemperature regulationTenrecs
TeratogenTermTermitesTernsTerracingTerritorialityTetanusTetrahedronTextilesThalidomideTheoremThermal expansionThermochemistryThermocoupleThermodynamicsThermometerThermostatThistleThoracic surgeryThrips
ThrombosisThrushesThunderstormTides
Trang 24Weaver finchesWeevilsWeldingWest Nile virusWetlandsWheatWhisk fernWhite dwarfWhite-eyesWhooping coughWild typeWildfireWildlifeWildlife trade (illegal)Willow family (Salicaceae)Wind
Wind chillWind shearWintergreenWolverineWombatsWoodWoodpeckersWoolly mammothWork
VacuumVacuum tubeValenceVan Allen beltsVan der Waals forcesVapor pressureVariableVariable starsVarianceVaricella zoster virusVariola virusVegetablesVeinsVelocityVenusVerbena family (Verbenaceae)Vertebrates
Video recordingViolet family (Violaceae)Vipers
Viral geneticsVireosVirtual particlesVirtual realityVirus
ViscosityVisionVision disordersVitaminViviparityVivisectionVolatilityVolcanoVolesVolumeVoyager spacecraftVulcanizationVultures
VX agent
W
Wagtails and pipitsWalkingsticksWalnut familyWalruses
Trang 25Y2KYakYamYeastYellow feverYewYttrium
Trang 26This page intentionally left blank
Trang 27The Gale Encyclopedia of Science, Third Edition
has been designed with ease of use and ready reference
in mind
• Entries are alphabetically arranged across six volumes,
in a single sequence, rather than by scientific field
• Length of entries varies from short definitions of one or
two paragraphs, to longer, more detailed entries on
more complex subjects
• Longer entries are arranged so that an overview of the
subject appears first, followed by a detailed discussion
conveniently arranged under subheadings
• A list of key terms is provided where appropriate to
de-fine unfamiliar terms or concepts
• Bold-faced terms direct the reader to related articles
• Longer entries conclude with a “Resources” section,
which points readers to other helpful materials
(includ-ing books, periodicals, and Web sites)
• The author’s name appears at the end of longer entries.His or her affiliation can be found in the “Contributors”section at the front of each volume
• “See also” references appear at the end of entries topoint readers to related entries
• Cross references placed throughout the encyclopediadirect readers to where information on subjects withouttheir own entries can be found
• A comprehensive, two-level General Index guidesreaders to all topics, illustrations, tables, and personsmentioned in the book
AVAILABLE IN ELECTRONIC FORMATS
Licensing The Gale Encyclopedia of Science, Third
Edition is available for licensing The complete database
is provided in a fielded format and is deliverable on suchmedia as disk or CD-ROM For more information, con-tact Gale’s Business Development Group at 1-800-877-GALE, or visit our website at www.gale.com/bizdev
ORGANIZATION OF THE ENCYCLOPEDIA
Trang 28This page intentionally left blank
Trang 29ACADEMIC ADVISORS
Marcelo Amar, M.D.
Senior Fellow, Molecular Disease Branch
National Institutes of Health (NIH)
University of South Carolina School of Medicine
Columbia, South Carolina
William J Engle P.E
Exxon-Mobil Oil Corporation (Rt.) New Orleans, Louisiana
Bill Freedman
ProfessorDepartment of Biology and School for Resource andEnvironmental Studies
Dalhousie UniversityHalifax, Nova Scotia, Canada
Antonio Farina, M.D., Ph.D
Department of Embryology, Obstetrics, andGynecology
University of BolognaBologna, Italy
Clayton Harris
Associate ProfessorDepartment of Geography and GeologyMiddle Tennessee State UniversityMurfreesboro, Tennesses
Trang 30encyclo-The University of Western Australia
Molecular Oncology and Development
Program/Boyer Center for Molecular Medicine
Yale University School of Medicine
New Haven, Connecticut
William S Pretzer
Curator
Henry Ford Museum and Greenfield Village
Dearborn, Michigan
Judyth Sassoon, Ph.D., ARCS
Department of Biology and Biochemistry
Michael J Sullivan, M.D., Ph.D., FRACP
Cancer Genetics LaboratoryUniversity of Otago
Dunedin, New Zealand
Richard Addison Wood
Meteorological ConsultantTucson, Arizona
Diego F Wyszynski, M.D., Ph.D
Department of Medicine, Epidemiology &
BiostatisticsBoston University School of MedicineBoston, Massachusetts
Rashmi Venkateswaran
Undergraduate Lab CoordinatorDepartment of ChemistryUniversity of OttawaOttawa, Ontario, Canada
LIBRARIAN ADVISORS Donna Miller
DirectorCraig-Moffet County LibraryCraig, Colorado
Judy Williams
Media CenterGreenwich High SchoolGreenwich, Connecticut
Trang 31Nasrine Adibe
Professor Emeritus
Department of Education
Long Island University
Westbury, New York
Georgia Southern UniversityStatesboro, Georgia
Carolyn Black
ProfessorIncarnate Word CollegeSan Antonio, Texas
Larry Blaser
Science WriterLebanon, Tennessee
Jean F Blashfield
Science WriterWalworth, Wisconsin
Richard L Branham Jr
DirectorCentro Rigional deInvestigaciones Científicas yTecnológicas
Mendoza, Argentina
Patricia Braus
EditorAmerican DemographicsRochester, New York
Dana M Barry
Editor and Technical WriterCenter for Advanced MaterialsProcessing
Clarkston UniversityPotsdam, New York
Puja Batra
Department of ZoologyMichigan State UniversityEast Lansing, Michigan
Donald Beaty
Professor EmeritusCollege of San MateoSan Mateo, California
Eugene C Beckham
Department of Mathematics andScience
Northwood InstituteMidland, Michigan
Martin Beech
Research AssociateDepartment of AstronomyUniversity of Western OntarioLondon, Ontario, Canada
Julie Berwald, Ph.D (Ocean Sciences)
Austin, Texas
Massimo D Bezoari
Associate ProfessorDepartment of ChemistryHuntingdon CollegeMontgomery, Alabama
John M Bishop III
TranslatorNew York, New York
CONTRIBUTORS
Trang 32Brandon R Brown
Graduate Research Assistant
Oregon State University
Toronto, Ontario, Canada
Scott Christian Cahall
Center for Quantum Mechanics
The University of Texas at Dallas
Physician and Medical Writer
Durham, North Carolina
Mary Ann Cunningham
Environmental Writer
St Paul, Minnesota
Les C Cwynar
Associate ProfessorDepartment of BiologyUniversity of New BrunswickFredericton, New Brunswick
Paul Cypher
Provisional InterpreterLake Erie MetroparkTrenton, Michigan
Stanley J Czyzak
Professor EmeritusOhio State UniversityColumbus, Ohio
Rosi Dagit
Conservation BiologistTopanga-Las Virgenes ResourceConservation District
Topanga, California
David Dalby
PresidentBruce Tool Company, Inc.Taylors, South Carolina
Lou D’Amore
Chemistry TeacherFather Redmund High SchoolToronto, Ontario, Canada
Douglas Darnowski
Postdoctoral FellowDepartment of Plant BiologyCornell University
Ithaca, New York
Sreela Datta
Associate WriterAztec PublicationsNorthville, Michigan
Sarah K Dean
Science WriterPhiladelphia, Pennsylvania
Kenneth B Chiacchia
Medical EditorUniversity of Pittsburgh MedicalCenter
Pittsburgh, Pennsylvania
M L Cohen
Science WriterChicago, Illinois
Robert Cohen
ReporterKPFA Radio NewsBerkeley, California
Sally Cole-Misch
Assistant DirectorInternational Joint CommissionDetroit, Michigan
George W Collins II
Professor EmeritusCase Western ReserveChesterland, Ohio
Jeffrey R Corney
Science WriterThermopolis, Wyoming
Tom Crawford
Assistant DirectorDivision of Publication andDevelopment
University of Pittsburgh MedicalCenter
Edward Cruetz
PhysicistRancho Santa Fe, California
Frederick Culp
ChairmanDepartment of PhysicsTennessee TechnicalCookeville, Tennessee
Trang 33New York University
New York, New York
New York University
New York, New York
Bill Freedman
ProfessorDepartment of Biology andSchool for Resource andEnvironmental StudiesDalhousie UniversityHalifax, Nova Scotia
T A Freeman
Consulting ArchaeologistQuail Valley, California
Elaine Friebele
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ClimatologistEotvos Lorand UniversityBudapest, Hungary
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EngineerSharon, Vermont
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AudiologistPortland, Oregon
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GeologistLas Vegas, Nevada
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Educational EnvironmentalWriting
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Instructor of BiologyThe North Carolina School ofScience and MathematicsDurham, North Carolina
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Science WriterMadison, Wisconsin
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Department of Astronomy andPhysics
Bloomberg CenterBaltimore, Maryland
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ProfessorQuinsigamond CommunityCollege
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Senior InstructorLloyd Center for EnvironmentalStudies
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Extension Specialist,Marine/Aquatic EducationVirginia State UniversityPetersburg, Virginia
Ed Fox
Charlotte Latin SchoolCharlotte, North Carolina
Trang 34South Granville High School
Durham, North Carolina
Hans G Graetzer
Professor
Department of Physics
South Dakota State University
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University of Rhode Island
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Department of Physical SciencePembroke State UniversityPembroke, North Carolina
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Instructor of Biology, Anatomy,Chemistry
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Senior Research FellowInstitute of Medical ResearchPapua, New Guinea
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(Geology)
GeologistPortland, Oregon
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Editor
The Amicus Journal
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Associate ProfessorDepartment of Geography andGeology
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ProfessorDepartment of Chemistry andPhysics
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Department of PhysicsLuther College Calmar, Iowa
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Science EducatorShelton, Nebraska
Trang 35Amy Kenyon-Campbell
Ecology, Evolution and
Organismal Biology Program
Los Alamos National Laboratory
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Associate News Editor
Journal of Cell Biology
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Trang 36Christine Miner Minderovic
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Trang 39In mathematics, to factor a number or algebraic
ex-pression is to find parts whose product is the original
number or expression For instance, 12 can be factored
into the product 6 2, or 3 4 The expression (x2- 4)
can be factored into the product (x + 2)(x - 2) Factor is
also the name given to the parts We say that 2 and 6 are
factors of 12, and (x-2) is a factor of (x2- 4) Thus we
refer to the factors of a product and the product of factors
The fundamental theorem of arithmetic states that
every positive integer can be expressed as the product of
prime factors in essentially a single way A prime
num-ber is a numnum-ber whose only factors are itself and 1 (the
first few prime numbers are 1, 2, 3, 5, 7, 11, 13)
Inte-gers that are not prime are called composite The
num-ber 99 is composite because it can be factored into the
product 9 11 It can be factored further by noting that
9 is the product 3 3 Thus, 99 can be factored into the
product 3 3 11, all of which are prime By saying
“in essentially one way,” it is meant that although the
factors of 99 could be arranged into 3 11 3 or 11
3 3, there is no factoring of 99 that includes any
primes other than 3 used twice and 11
Factoring large numbers was once mainly of interest
to mathematicians, but today factoring is the basis of the
security codes used by computers in military codes and
in protecting financial transactions High-powered
com-puters can factor numbers with 50 digits, so these codes
must be based on numbers with a hundred or more digits
to keep the data secure
In algebra, it is often useful to factor polynomial
expressions (expressions of the type 9x3+ 3x2 or x4
-27xy + 32) For example x2+ 4x + 4 is a polynomial that
can be factored into (x + 2)(x + 2) That this is true can
be verified by multiplying the factors together The
de-gree of a polynomial is equal to the largest exponent
that appears in it Every polynomial of degree n has at
most n polynomial factors (though some may contain
complex numbers) For example, the third degree
poly-nomial x3+ 6x2+ 11x + 6 can be factored into (x + 3) (x2+ 3x + 2), and the second factor can be factored againinto (x + 2)(x + 1), so that the original polynomial hasthree factors This is a form of (or corollary to) the fun-damental theorem of algebra
In general, factoring can be rather difficult Thereare some special cases and helpful hints, though, thatoften make the job easier For instance, a common factor
in each term is immediately factorable; certain common
situations occur often and one learns to recognize them,such as x3+ 3x2+ xy = x(x2+ 3x + y) The difference oftwo squares is a good example: a2- b2= (a + b)(a - b).Another common pattern consists of perfect squares ofbinomial expressions, such as (x + b)2 Any squared bi-nomial has the form x2+ 2bx + b2 The important things
to note are: (1) the coefficient of x2is always one (2) thecoefficient of x in the middle term is always twice the
square root of the last term Thus x2 + 10x + 25 =(x+5)2, x2- 6x + 9 = (x-3)2, and so on
Many practical problems of interest involve mial equations A polynomial equation of the form ax2+
polyno-bx + c = 0 can be solved if the polynomial can be tored For instance, the equation x2+ x - 2 = 0 can bewritten (x + 2)(x - 1) = 0, by factoring the polynomial.Whenever the product of two numbers or expressions is
fac-zero, one or the other must be zero Thus either x + 2 = 0
or x - 1 = 0, meaning that x = -2 and x = 1 are solutions
of the equation
Resources Books
Bittinger, Marvin L, and Davic Ellenbogen Intermediate bra: Concepts and Applications 6th ed Reading, MA:
Alge-Addison-Wesley Publishing, 2001.
Davison, David M., Marsha Landau, Leah McCracken, Linda
Immergut, and Brita and Jean Burr Smith Arithmetic and
Algebra Again New York: McGraw Hill, 1994.
Larson, Ron Precalculus 5th ed New York: Houghton Mifflin
College, 2000.
F
Trang 40McKeague, Charles P Intermediate Algebra 5th ed Fort
Worth: Saunders College Publishing, 1995.
J.R Maddocks
Factorial
The number n! is the product 1 2 3 4
n, that is, the product of all the natural numbers from 1
up to n, including n itself where 1 is a natural number It
is called either “n factorial” or “factorial n.” Thus 5! is
the number 1 2 3 4 5, or 120
Older books sometimes used the symbol In for n
factorial, but the numeral followed by an exclamation
point is currently the standard symbol.
Factorials show up in many formulas of statistics,
probability, combinatorics, calculus, algebra, and
else-where For example, the formula for the number of
per-mutations of n things, taken n at a time, is simply n! If a
singer chooses eight songs for his or her concert, these
songs can be presented in 8!, or 40,320 different orders
Similarly the number of combinations of n things r at a
time is n! divided by the product r!(n - r)! Thus the
num-ber of different bridge hands that can be dealt is 52!
di-vided by 13!39! This happens to be a very large number.
When used in conjunction with other operations, as
in the formula for combinations, the factorial function
takes precedence over addition, subtraction, negation,
multiplication, and division unless parentheses are used
to indicate otherwise Thus in the expression r!(n - r)!,
the subtraction is done first because of the parentheses;
then r! and (r - n)! are computed; then the results are
multiplied
As n! has been defined, 0! makes no sense However,
in many formulas, such as the one above, 0! can occur If
one uses this formula to compute the number of
combina-tions of 6 things 6 at a time, the formula gives 6! divided
by 6!0! To make formulas like this work, mathematicians
have decided to give 0! the value 1 When this is done,
one gets 6!/6!, or 1, which is, of course, exactly the
num-ber of ways in which one can choose all six things
As one substitutes increasingly large values for n,
the value of n! increases very fast Ten factorial is more
than three million, and 70! is beyond the capacity ofeven those calculators which can represent numbers inscientific notation
This is not necessarily a disadvantage In the seriesrepresentation of sine x, which is x/1! - x3/3! + x5/5! - ,the denominators get large so fast that very few terms of
the series are needed to compute a good decimal
ap-proximation for a particular value of sine x.
Fahrenheit see Temperature
Falcons
Falcons are birds of prey in the family Falconidae There are 39 species of true falcons, all in the genus
Falco Like other species in the order Falconiformes
(which also includes hawks, eagles, osprey, and
vul-tures), falcons have strong raptorial (or grasping) talons,
a hooked beak, extremely acute vision, and a fierce meanor Falcons can be distinguished from other raptors
de-by the small toothlike serrations (called tomial teeth) ontheir mandibles and by their specific coloration They
also have distinctive behavior patterns, such as killing their prey by a neck-breaking bite, head-bobbing, defe- cating below the perch or nest, and an often swift and
direct flight pattern
Falcons can be found on all continents except
Antarctica Some species have a very widespread
distri-bution In particular, the peregrine falcon (F.
peregrinus) is virtually cosmopolitan, having a number
of subspecies, some of them specific to particular
ocean-ic islands Other falcons are much more restrocean-icted in
their distribution: for example, the Mauritius kestrel (F.
puctatus) only breeds on the island of Mauritius in the
Indian Ocean At one time, fewer than ten individuals of
this endangered species remained, although populations
have since increased as a result of strict protection and aprogram of captive breeding and release
Species of falcons exploit a very wide variety of
habitat types, ranging from the high arctic tundra to
bo-real and temperate forest, prairie and savanna, and cal forests of all types Falcons catch their own food.
tropi-Most species of falcons catch their prey in flight, althoughkestrels generally seize their food on the ground, oftenafter hovering above As a group, falcons eat a great range
of foods; however, particular species are relatively specific
in their feeding, limiting themselves to prey within certain
size ranges The American kestrel (F sparverius), for
ex-ample, eats mostly insects, earthworms, small mammals, and small birds, depending on their seasonal availability.
KEY TERMS .
Product—The product of two numbers is the
number obtained by multiplying them together