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第一篇MoreThan8HoursSleepTooMuchofaGoodThing1Althoughthedangersoftoolittlesleeparewidelyknown,newresearchsuggeststhatpeoplewhosleeptoomuchmayalsosuffertheconsequences.2InvestigatorsattheUniversityofCaliforniainSanDiegofoundthatpeoplewhoclockup19or10hourseachweeknightappeartohavemoretroublefallingandstayingasleep,aswellasanumberofothersleepproblems,thanpeoplewhosleep8hoursanight.Peoplewhosleptonly7hourseachnightalsosaidtheyhadmoretroublefallingasleepandfeelingrefreshedafteranight’ssleepthan8-hoursleepers.23Thesefindings,whichDr.DanielKripkereportedinthejournalPsychosomaticMedicine3,demonstratethatpeoplewhowanttogetagoodnight’srestmaynotneedtosetaside4morethan8hoursanight.Headdedthat“itmightbeagoodidea”forpeoplewhosleepmorethan8hourseachnighttoconsiderreducingtheamountoftimetheyspendinbed,butcautionedthatmoreresearchisneededtoconfirmthis.4Previousstudieshaveshownthepotentialdangersofchronicshortagesofsleep—forinstance,onereportdemonstratedthatpeoplewhohabituallysleeplessthan7hourseachnighthaveahigherriskofdyingwithinafixedperiodthanpeoplewhosleepmore.5Forthecurrentreport,Kripkereviewedtheresponsesof1,004adultstosleepquestionnaires,inwhichparticipantsindicatedhowmuchtheysleptduringtheweekandwhethertheyexperiencedanysleepproblems.Sleepproblemsincludedwakinginthemiddleofthenight,arisingearlyinthemorningandbeingunabletofallbacktosleep,andhavingfatigueinterferewithday-to-dayfunctioning5.6Kripkefoundthatpeoplewhosleptbetween9and10hourseachnightweremorelikelytoreportexperiencingeachsleepproblemthanpeoplewhoslept8hours.Inaninterview,Kripke第一篇每晚只需8个小时，睡眠过多非益事睡眠不足带来的危害已经广为人知，而一项新的研究表明睡眠过多同样会产生不良后果。圣地亚哥加利福尼亚大学的研究人员发现在入睡、保持睡眠等方面，每晚睡9或10小时的人比睡8小时的人存在更多问题。与8小时睡眠者相比，每晚仅睡7个小时的人则表示，他们在入睡及经过一夜睡眠后精力恢复方面有更多的麻烦。DanielKripke愽士在《心身医学》杂志上报告的这些新发现表明，人们如果想晚上休息好，每天留给睡眠的时间只需8个小时。他补充说，对于那些每晚睡8个小时以上的人们来说，考虑减少在床上度过的时间“也许是个好主意”。不过他又提醒说这还需要进一步的研究证实。以往的研究证明了长期睡眠缺乏的潜在危机。有报告显示，睡眠经常少于7小时的人比睡眠充足者，在特定时期内死亡的机率更高。而在目前这份报告中，Kripke考评了一份1004名成年人参与反馈的睡眠调查问卷。问卷内容涉及每周睡眠时间和各种可能的睡眠问题，包括半夜惊醒、清晨早醒、无法重新入睡，以及白天疲劳影响日常工作等。Kripke发现每晚睡9～10小时的人比睡8个小时的人更容易出现各类睡眠问题。在一次访谈中，Kripke注意到睡眠时间长的人夜间可能难以入眠，正是因为他们notedthatlongsleepersmaystruggletogetrestatnightsimplybecausetheyspendtoomuchtimeinbed.Asevidence,headdedthatonewaytohelpinsomniaistospendlesstimeinbed.“Itstandstoreasons6thatifapersonspendstoolongatimeinbed,thenthey’llspendahigherpercentageoftimeawake,”hesaid.睡得太多了。因此他补充说，治疗失眠昀好的一种方法就是少睡点儿。“在床上花的时间过长，醒着的时间就会更多，这是理所当然的。”第二篇SootandSnow:aHotCombination1NewresearchfromNASAscientistssuggestsemissionsofblacksootalterthewaysunlightreflectsoffsnow.Accordingtoacomputersimulation,blacksootmayberesponsiblefor25percentofobservedglobalwarmingoverthepastcentury.2SootinthehigherlatitudesoftheEarth,whereiceismorecommon,absorbsmoreofthesun’senergyandwarmththananicy,whitebackground.Dark-coloredblackcarbon,orsoot,absorbssunlight,whilelightercoloredicereflectssunlight.3Sootinareaswithsnowandicemayplayanimportantroleinclimatechange.Also,ifsnowandicecoveredareasbeginmelting,thewarmingeffectincreases,asthesootbecomesmoreconcentratedonthesnowsurface.“Thisprovidesapositivefeedback,asglaciersandicesheetsmelt,theytendtogetevendirtier,”saidDr.JamesHansen,aresearcheratNASA’sGoddardInstituteforSpaceStudies,NewYork.4Hansenfoundsoot’seffectonsnowalbedo(solarenergyreflectedbacktospace),which1maybecontributingtotrendstowardearlyspringsintheNorthernHemisphere,suchasthinningArcticseaice,meltingglaciersandpermafrost.Sootalsoisbelievedtoplayaroleinchangesintheatmosphereabovetheoceansandland.5“Blackcarbonreducestheamountofenergyreflectedbysnowbackintospace,thusheatingthesnowsurfacemorethaniftherewerenoblackcarbon2,”Hansensaid.Soot’sincreasedabsorptionofsolarenergyisespeciallyeffectiveinwarmingtheworld’sclimate.“Thisforcingis第二篇煤灰与白雪：“火热”的组合美国国家航空和航天局的科学家的一项新调查显示，黑色煤烟的排放改变了冰雪对阳光的反射。依据电脑模拟，上世纪观测到的全球变暖有25%是黑煤灰引起的。地球高纬地区冰雪覆盖，那里的煤灰比白色的冰面吸收了更多的太阳热能。因为深黑色的炭或煤灰吸收太阳光，而浅色的冰面则反射阳光。冰雪地区的煤灰对气候变化可能起着至关重要的作用。而且一旦覆盖大地的冰雪开始融化，煤灰就会更加固着于冰面，从而加剧温室效应。“冰山、冰块一融化，就会变得更脏”。JamesHansen博士，一位来自纽约美国国家航空和航天局的Goddard太空研究所的研究人员如此说。Hansen发现，煤灰对冰雪反射率的影响，可能正是促使北半球春季提早的原因，引起北冰洋冰层变薄，冰山及冻土雪原融化。相信煤灰对海洋和陆地上空大气层的变化也有一定影响。“黑炭减少了冰雪反射回太空的能量，比没有炭灰的条件下更强烈地加热冰面。”Hansen说。煤灰对太阳热能的大量吸收是全球气候变暖的重要因素。Hansen指出，“这种温室作用特别显著，是同量二氧化unusuallyeffective,causingtwiceasmuchglobalwarmingasacarbon-dioxideforcingofthesamemagnitude,”Hansennoted.6Hansencautioned,althoughtheroleofsootinalteringglobalclimateissubstantial,itdoesnotalterthefactthatgreenhousegasesaretheprimarycauseofclimatewarmingduringthepastcentury.3Suchgasesareexpectedtobethelargestclimateforcingfortherest4ofthiscentury.7TheresearchersfoundthatobservedwarmingintheNorthernHemispherewaslargeinthewinterandspringatmiddleandhighlatitudes.Theseobservationswereconsistentwiththeresearchers’climatemodelsimulations,whichshowedsomeofthelargestwarmingeffectsoccurredwhentherewereheavysnowcover5andsufficientsunlight.碳强度的两倍。”Hansen又提醒说，尽管煤灰对全球气候变化的作用重大，但这并不能改变一个事实：温室气体是上世纪气候变暖的首要原因，而且它们还将是塑造本世纪气候的主力。研究人员发现北半球观测到的变暖现象大多发生在中高纬地区的冬春两季。这样的观测结果与气象模拟实验相吻合，表明部分大规模的温室效应发生在有厚雪覆盖层和强烈阳光的时期。第三篇IcyMicrobes1InicethathassealedasaltyAntarcticl