Scientific American 60 Second ScienceWord文件下载.docx
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Scientific American 60 Second ScienceWord文件下载.docx
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Ithasatleastonegenenecessaryforphotosynthesis—sofarit’stheonlyanimalknownwiththisability.Butitneedssomehelp,thegeneitselfisn’tenough.Soseaslugseatalgae.Theyslitopentheorganismsandsuckoutthecytoplasm.Theslugsdigestmostofthealgae,butthoseplastidsremainwholeandundigested.Andthentheplastidskeepondoingwhattheydo,whichisconvertsunlighttousableenergy.Oncetheseaslughaseatenenoughalgae,andgainedenoughplastids,itcanliveoffjustsunlightforuptoninemonths.Whenitcomestoenergy,thisslugneedsnoplug.
—CynthiaGraber
December2,2008
RobotClamAchievesFeatwithFoot
M.I.T.researchershaveinventedaroboticclam--whichmeansthey'
vereallydevelopedasmartanchorforsmallvessels.CynthiaGraberreports
M.I.T.scientistshavedesignedanewrobot.You’llprobablyneverseeitthough—it’smeanttobehidden.Becauseit’sarobotclam.Engineerswantedtodesignalightweightanchorthatcouldbeeasilysetandthenpickedup.That’snotpossiblewithconventionalanchors.Amoretalentedanchorwouldbegreatfor,say,smallsubmarinesthatmovearoundconstantlytotestoceantemperaturesandcurrents.
Razorclamspresentedtheidealbiologicalmodel.Theycanburrowacentimeterpersecondmorethantwofeetdownintothesoil,wheretheycananchorthemselvestightlytotheoceanfloor.Scientistssetupaglassboxwithwaterandbeadsandstuckalivingrazorclaminside.Theyfilmedwhathappenednext.Theanimal’sfootwiggledintothebeads.Therestoftheclamfollowedbymovingquicklyupanddownandrapidlyopeningandclosingitsshell.Bycarefullyanalyzingthefilm,thescientistsdiscoveredsomethingsurprising.Theclam’smovementsturnthesandaroundthecreatureintomoreofafluid—basicallyquicksand.Bycopyingthissystem,M.I.T.researcherscreatedatinyRoboClam.It’sthesizeofacigarettelighter.Iftheyaddartificialintelligence,wecanfindoutifthedeviceishappyasaclam.
December3,2008
UsingRadartoMonitorBabyBreathing
UniversityofFloridaengineershavecreatedaprototypebabymonitorthatusesDopplerradartotrackthemovementsofababy'
schest,indicatingbreathingstatus.SteveMirskyreports
[Radiosound:
]“Northeast480youareclearedforlanding,Northeast480youareclearedforlanding.”
Thatsameradartechnologythatguidesaircraftandtrackshurricanescouldinthefuturekeeptrackofababy’sbreathing.EngineersfromtheUniversityofFloridahavebuiltaprototyperadarbabymonitor.Thecrib-mountedmonitordetectsmovementoftheinfant’schestusingDopplerradar.Ifbreathingstops,movementstopsandthemonitorsoundsanalarm.Suchasystemshouldbesuperiortothosethatjustsendsoundorvideototheparents.TheresearchwillappearintheFebruaryissueofIEEEMicrowaveMagazine.IEEEistheInstituteofElectricalandElectronicsEngineers.
Theradarmonitorthattheresearcherscreatedisaboutthesizeofsmallbook.Thereceiverindicatesthebaby’sbreathing,aswellasthestateofthewirelessconnectionwiththemonitorandthebatterystatus.Futureversionscouldalsodetectheartbeatthroughahigherfrequencysignal.
]“Mrs.WatsononMapleDrive,yourbabyisbreathingnormally,thebabyisbreathingnormally.”
—SteveMirsky
December4,2008
BraheBurstBroughttoLight
Astronomershavecollectedlightbouncingaroundsincea1572supernova,witnessedbyTychoBrahehimself,tofigureoutexactlywhatkindofexplosionitwas.CynthiaGraberreports
It’snoteverydaywegetachancetotimetravel.Otherthanintothefutureattherateofonesecondpersecond.Butastronomerssaythey’vedonealittletravelingintothepast.InNovemberof1572,legendaryastronomerTychoBrahepeeredupatthenightsky.HesawwhatlookedlikeastrangelybrightstarintheconstellationCassiopeia.ItwasbrightereventhanthenearbyplanetVenus.Hestudiedthatbrightnewstarforfivemonths,untilitfadedaway.ButwhatBrahesawwasn’tanewstar.Itwasactuallyanoldstarundergoingthebrilliantlybrightdeathofasupernova.
ScientistsattheSubaruTelescopeinJapanrecentlyanalyzedwhatcouldbecalledechoesofthismorethan400-year-oldevent.TheypublishedtheirresearchintheDecember4thissueofthejournalNature.Lightfromtheoriginalsupernovabouncedoffdustparticlesintheinterstellarcloudsandeventuallyreachedushereonearthmorethanfourcenturieslater.ScientistsusedtheseechoestodeterminethatBrahewitnessedatypeIasupernova.
December5,2008
HappinessIsContagious
Ahappypersonwithinasocialcirclequicklyinfluencesthosearoundhimorhertobehappy,extendingtothreedegreesofseparation.AdamHinterthuerreports
Wanttoliveahappierlife?
Trysurroundingyourselfwithhappyfriendsoratleastfindfriendswithhappyfriends.AstudypublishedonlineDecember4thintheBritishMedicalJournalsayshappinesscanquicklygoviralwithinyoursocialnetwork.
Researcherslookedattwentyyears'
worthofdataonmorethan5,000individualsandfoundthatwhenanyonepersonwashappy,theirfriendsbecamemorelikelytosharethatjoy.Benefitsspreadouttothreedegreesofseparation,meaningabetterchanceathappinessfornotonlytheirfriends'
friends,butalsotheirfriends'
friends'
friends.
Butdon'
tgothinkingyourtenthousandbuddiesonFacebookwillbringyouhappiness.Theresearchersfoundthatthestrengthoftheeffectdissipatesoverphysicaldistance,withnext-doorneighborsandfriendslivingnearbygettingthebiggestboost.Surprisingly,sadnessmadeverylittleheadwaywithinsocialnetworks,palingincomparisontothecommunaleffectsofhappiness.Justintimefortheholidayseason,scientificproofthatit'
snotthegiftthatcounts—it’sthesmileonthefaceofthefriendgivingit.
—AdamHinterthuer
December8,2008
WarmClimatesSupportLongerLimbs
Astudywithmicefindsthatthosekeptinwarmerenvironmentsdeveloplongerlimbsthantheirchilliercousins,thankstoenhancedcartilagegrowth.KarenHopkinreports
Animalsthatliveincoldclimatestendtohavestubbylimbs—shorterarmsandlegs—evensmallerearsandtails.Pictureapenguinandyou’llseewhatImean.Biologistshavelongassumedthatthesestumpyappendagesareanevolutionaryadaptation.Shorterextremitiesminimizeheatloss,soanimalsthataremorecompactarebettersuitedtothecold.
ButscientistsfromOhiosaythattemperaturemayhaveamoredirecteffectonthelengthofananimal’slimbs.Becausetheyfindthatturninguptheheathelpscartilagegrow—resultsthatwerepublishedintheProceedingsoftheNationalAcademyofSciences.
Theresearchersraisedmiceatseveraldifferenttemperatures,andtheyconfirmedthatthosekeptatabalmy80degreeswerelongerlimbedthanthosewholivedatamorechill45.Buthowdoesalittleheatmakemicemoreleggy?
Theanswer,theyfind,liesinthecartilage.Longbonesgrowfromthecartilagefoundateitherend.Andthewarmeritis,themorethatcartilagegrows,evenwhenit’sjustsittinginatesttube.WhichIguessmeansit’spossiblethatthedogdaysofsummerleadtolonger-leggeddogs.
—KarenHopkin
December9,2008
TraditionalTreatmentsShowPromiseforHIV,Psoriasis
TraditionalChinesemedicine'
sastragalusrootshowspromiseinHIVtreatment,andtheplantextract,indigonaturalis,mayhelpcalmtheskinconditionpsoriasis.CynthiaGraberreports
Chinesemedicinehasbeengettingsomepropslately.Acoupleofrecentstudieshavedemonstratedthemedicalpotentialoftraditionaltreatments.
PartofthechallengeofAIDSisthatimmunecellslosetheirabilitytodivideandthustheirdiseasefightingpower.Partlybecausethetelomeres—asortofprotectivecapontheendsofchromosomes—becomeprogressivelyshorter.Entertherootastragalus.It’susedfrequentlyinChineseherbalremedies.ResearchersfocusedonachemicalcalledTAT2,whichwasidentifiedinastragalus.TheytesteditoncellsandbloodfromHIVinfectedindividuals.ThecompoundslowedtheshorteningoftelomeresandgenerallyimprovedtheabilityofcellstofightHIV.(TheJournalofImmunology)
Anotherstudyfocusedonpsoriasis.There’snocureforthatchronicskindisease.ButinChinaandTaiwan,peoplewithpsoriasisfrequentlyapplyadarkblueplant-basedpowdercalledindigonaturalis.Inarandomizedstudy[intheArchivesofDermatology],indigopowdersignificantlyreducedskinscaling,rednessandhardness.TheTaiwanesescientistssaythenextstepistodetermineindigo’spharmacologyandperhapsextractthespecificchemicalcompoundsthatcouldbringpsoriasissuffererssomerelief.
December10,2008
ImmigrantElephantsStickTogether
Whenelephantsaretransportedtonewhabitats,theimmigrantstendtosticktogether,onlyslowlyassimilatingintotheexisting
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