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ID:41224593
大小:1.00 MB
页数:43页
时间:2019-08-19
《FORENSICSCIENCETraceEvidence法医学物证》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、FORENSICSCIENCETraceEvidence1IntroductionTraceEvidence--anysmallpiecesofmaterial,man-madeornaturallyoccurringMostcommonexamples:HairFiber2TestQuestionsforTraceEvidenceWhatisit?Isitman-madeornatural?Whatisitssource?Howcommonisit?Canitbeidentifiedtoasi
2、nglesource?3HairHumanhairisoneofthemostfrequentlyfoundpiecesofevidenceatthesceneofaviolentcrime.Itcanprovidealinkbetweenthecriminalandtheact.Fromhaironecandetermine:HumanoranimalRaceOriginMannerinwhichhairwasremovedTreatedhairDrugsingested4DNAThehairsh
3、aftcontainsabundantmitochondrialDNA--inheritedonlyfromourmothers.ItcanbetypedbycomparingrelativesifnoDNAfromthebodyisavailable.OnlytherootcontainsnuclearDNA.5HairMorphologyTheStudyofStructureandFormPartsofthehairShaft--partofthehairthatsticksoutofthesk
4、inRoot--liesbelowtheepidermisFollicle--structurefromwhichthehairgrows6HairGrowthTerminologyAnagen--hairthatisgrowingCatagen--hairatrestTelogen--hairthatisdyingLength--00.5mmperdayor1centimeterpermonth;approximatelyonehalfinchpermonth7HairCuticleMosaicP
5、ectinateImbricatePetalDiamondpetalChevronThecuticleistheoutermostlayerofhairwhichiscoveredwithscales.Scalesalsoalwayspointtowardthetipofthehair.Thesescalesdifferbetweenspeciesofanimalsandarenamesbasedontheirappearance.Someofthesescalesarevariationsofth
6、esameandinclude:8ScaleTypesMosaicChevron9ScaleTypes(cont)PectinateImbricate10ScaleTypes(cont)PetalDiamondPetal11HUMANSCALESInordertovisualizethescalespaintfingernailpolishonaslideplaceahaironthepolishliftoffthehairandobservethescaleimprintsWhatpatterni
7、sseeninthisslide?12HairCortexThecortexgivesthehairitsshape.Ithastwomajorcharacteristics:Melanin--pigmentgranulesthatgivehairitscolorCorticalfusi--airspaces,usuallyfoundneartherootbutmaybefoundthroughoutthehairshaft13Themedullaisthehaircorethatisnotalwa
8、yspresent.Themedullacomesindifferenttypesandpatterns.Types:ContinuousIntermittentorinterruptedFragmentedAbsent--notpresentHairMedulla14HairMedullaPatternsUniserialMultiserialVacuolatedLatticeAmorphous(withoutadistinctpattern)15HUMANMEDU
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