尼安德特人为母、丹尼索瓦人为父：科学家首次发现2种古人类“混血儿”前网OER百家号J18-08-2715:24近日，研究人员在对西伯利亚洞穴中发现的一根人骨做基因组分析后，惊喜地发现，这名生活在约9万年前的女性身上，竟然有一半的尼安德特人血统和一半丹尼索瓦人血统。这是科学家们第一次发现2种不同古人类群体的第一代混血儿。这项研究结果也于8月22日发表在《自然》杂志上。（尼安德特人复原图，图片来源于《自然》）弗朗西斯克里克研究所人类遗传学家斯克伦德（PontusSkoglund）说：从这些群体中找到第一代混血儿是非常了不起的成就，这真是伟大的科学精神加上一点运气的结果。由德国菜比锡马克斯普朗克进化人类学研究所的古遗传学家斯隆（VivianeSlon）和帕阿波(SvantePaabo）领导的研究小组，对从俄罗斯阿尔泰山脉丹尼索瓦山洞中找到的人类骨头碎片进行了基因组分析。这个洞穴以已经灭绝的古人类丹尼索瓦人命名，因为在2008年，科学家正是在这个洞穴中发现了节指骨尖端，通过DNA测序，提出了丹尼索瓦这个新的古人类群体。值得注意的是，另一古代人种一一尼安德特人，同样分布在阿尔泰地区，科学家在
Acta Geologica Sinica (English Edition).2020.94(1):189-197ArtificialIntelligenceIdentificationofMultipleMicrofossilsfromtheCambrianKuanchuanpuFormation in SouthernGSCShaanxi, ChinaZHANGTao',2,WANGBin*,LIDedong,NIUBen',SUNJie2,SUNYifei?YANGXiaoguang,LUOJuanandHANJian'School of Information Science&Technology,Northwest University.Chang'an District,Xi'an 710075,China2ShaanxiKeyLaboratory ofEarlyLifeandEnvironmensts,StateKeyLaboratoryofContinentalDynamics,DepartmentofGeology,NorthwestUniversity,Xi'an710069,China.Abstract:The Cambrian Kuanchuanpu Formation in southern Shaanxi, China is a critical windowfor the understanding ofthe Cambrian explosion, because of abundant and various exceptionally preserved metazoans and embryo fossils yielded.The efficiency of traditional sample manually selecting with microscopes is quite lowand hinderthe discoveries of newspecies,thus recognition and classification of microfossils by artificial intelligence (Al) is substantially in the request. Inthis paper,we develop a procedure for fossil area segmentation in common multi-typed mixed photos by improvedwatershed algorithm.And for better fossil recognition, previous histogram of oriented grandient (HOG) algorithm isreplaced by scale invariant feature transform (SIFT), which is feasible for the segmented images and increase the accuracysignificantly.Thus,the scopeof application of AIfossil recognition canbe extended form singlefossil imagetomulti-typedmixed images and thereliability is also secured, as the result of ourtest presents a high (at least84%)accuracy of fossilrecognition.Keywords:watershed segmentation,scaleinvariantfeaturetransform,visual vocabulary,support vector machine
(b)(a)II-SIFTIl-SourceH-SIFT(e)12-SIFTI3-SIFTIn-SIFT(c)II-TF1234-..12-Source12-SIFT12-TF128-dim(f)AIDF13-TFK-Means13-SourceI3-SIFTClustering1234K(d)IDFIn-TFIn-SIFTIn-Source128-dim2345234KVisual VocabularyFig.4.TheprocessofconstructingtheSIFT-BoWmodel (visualvocabulary).(a)Thesegmentedfossil imagelistincludingtubularfossil,spheroidal fossil,residuedetritus,(b)theSIFTfeaturepointsoffossil images,(c)matrixof SIFTfeaturesof all images in thetraining set,(d)visual vocabularyformedbyK-Means clustering,(e)frequency statistic of SIFTfeatures withinvisual vocabularyof each image (TF);(f)inversedocument frequencycalculatedbyaccumulating eachhistogram inC (IDF)
RESEARCHlages and calibratethis sequencetoacurrentPALEONTOLOGYestimateofthegeologicaltimescaleusingtheA high-resolution summary of Cambrian to Earlybest available chronostratigraphic data (16)Ourstudyfocused onmarineinvertebratesTriassic marine invertebrate biodiversityand used data from3766published stratigraphicsections,including266,110localreJun-xuanFan*2,Shu-zhong Shen2.3x,Douglas H.rwin4.5,PeterM.Sadler,NormanMacLeodcords of the stratigraphic ranges of 45,318taxonomicunits,covering all Chinese CambrianQiu-mingCheng.Xu-dongHou,JiaoYangXiang-dongWangYueWang?HuaZhangXuChen?toLowerTriassictectonicblocks (fig.S1).Al-Guo-xiangLi2,Yi-chun ZhangYu-kun Shi',Dong-xunYuan2,QingChen2,Lin-na Zhangthough our data werelargely derived fromChaoLi,Ying-yingZhaoChinese sections,thetectonicblocksonwhichthey reside were situated in paleolatitudesOnegreat challenge in understandingthehistory oflife isresolving the influenceofenvironmentalstretchingfrom southern Gondwananto northchange on biodiversity. Simulated annealing and genetic algorithms were used to synthesize data fromernBoreal realms(17).Accordingly,thesedata11,000marinefossil species,collectedfrommorethan3000stratigraphicsections,togenerateanewreflectglobal biodiversitypatterns (figs.S2CambriantoTriassicbiodiversitycurvewithan imputedtemporal resolutionof26±14.9thousandyears.ands3)This increased resolution clarifies the timing of known diversification and extinction events.ComparativeOur initial analyses revealed that the rarityanalysis suggests that partial pressureof carbon dioxide(Pco2)is the only environmentalfactorthat seemsof Silurian-Devonian data in China (duetoto displaya secular pattem similartothatofbiodiversity,but this similaritywas not confirmed whenworldwideregression)hamperedregional andautocorrelation within that time series was analyzed by detrending.These results demonstrate that fossilglobal correlations.Consequently,we added adata can providethetemporal and taxonomicresolutions necessarytotest (paleo)biological hypotheses ataDownloadedfromhttp://science.sciensmall amountof European Silurian-Devonianlevel of detail approaching those of long-term ecological analyses.data to improvethe correlations inthis in-terval.These additional data did not alternderstandingpatterns ofglobaldiversityearlyPaleozoic().Taxonageassignmentswerethegeneralityofourresults because differentChinesetectonicblocks were located in dif-canrevealthehistoryof thebiospheresubjecttoerror,notequallyapplicabletoalandrelationsbetweenenvironmentalclades, and quicklybecameoutdatedbynewferent regions during thePaleozoic,with somechangesand diversityfluctuations,andcorrelations or updated age estimates.Pre-residingcloseto Europe(fig.S3).Ourstudycan provideinsights intohowthefossilviousanalyses havealsobeenperformed atintervalterminated atthe late MiddleTriassicrecordmightinformcurrentbiodiversitycon-taxonomicallybroad andphylogeneticallymarine regressioncerns.Earlyglobal-scalequantitative analysissuspectfamilyorgenuslevels.SuchresolutionsTaxonomicnamesinopen nomenclatureidentifiedwhathavecometobeknown astheare oftentoo crudeand imprecisetoassessdi-questionabletaxa,andtaxaunidentifiableto"bigfive"massextinctions.However,suchef-versificationratesorpatterns associatedwiththespecies level were not included.SpeciesFnrtedanandnn+hannalithtnemlnhalatefnnnaalotanricaacnltnnnaa
天河二号是由国防科大店研制的超级天河二号河二号电计算机系统主丰成为2013年.福全球最快超天河二号级计算机
天河二号是 由国防科大 研制的超级 计算机系统， 成为2013年 全球最快超 级计算机