学科分类
/ 1
10 个结果
  • 简介:Background:Weexplorethefactorsaffectingtheoptimalplotdesign(sizeandtypeaswellasthesubsampletreeselectionstrategieswithinaplot)andtheirrelativeimportanceindefiningtheoptimalplotdesigninamultipurposeforestinventory.Thefactorsincludetimeusedtolayouttheplotandtomakethetreemeasurementswithintheplot,thebetween-plotvariationofeachofthevariablesofinterestinthearea,andthemeasurementandmodelerrorsforthedifferentvariables.Methods:WesimulatedifferentplottypesandsizesandsubsampletreeselectionstrategiesonmeasuredtestareasfromNorthLapland.Theplottypesusedarefixed-radius,concentricandrelascopeplots.Weselecttheoptimaltypeandsizefirstatplotlevelusingacost-plus-lossapproachandthenatclusterlevelbyminimizingtheweightedstandarderrorwithfixedbudget.Results:Asrelascopeplotsareveryefficientattheplotlevelforvolumeandbasalarea,andfixed-radiusplotsforstemsperha,theoptimalplottypestronglydependsontherelativeimportanceofthesevariables.Theconcentricplotseemstobeagoodcompromisebetweenthesetwoinmanycases.Thesubsampletreeselectionstrategywasmoreimportantinselectingoptimalplotthanmanyotherfactors.Inclusterlevel,themostimportantfactoristhetransfertimebetweenplots.Conclusions:Whiletheoptimalradiusofplotsandotherparametersweresensitivetothemeasurementtimesandothercostfactors,theconcentricplottypewasoptimalinalmostallstudiedcases.Subsampletreemeasurementstrategiesneedfurtherstudies,astheywereanimportantcostfactor.However,theirimportancetotheprecisionwasnotasclear.

  • 标签: 森林资源清查 优化设计 库存 用途 选择策略 成本因素
  • 简介:ThispaperexaminestheplotstructuresofConrad’s“AmyFoster”andAlmayer’sFolly.Theydon’tfollowtheruleofconventionalplotstructure;rather,theyareConrad’selaborateexperimentsofmodernistconstruction,whichfeatureslayersofflashbacks.Thebenefitofsucharrangementisthevigorousinteractionbetweenthetextandthereaders.

  • 标签: modernist PLOT construction flashback frame STORY double
  • 简介:Middleearsurgerytechniqueshaveenabledtoimprovehearingdestroyedbyadisease.Despitehugeimprovementininstrumentationandtechniquestheresultsofhearingimprovementsurgeryarestilldifficulttopredict.ThispaperpresentstheresultsofvibrationsmeasurementsinahumanmiddleearobtainedattheMedicalUniversityofLublin.Vibrationsofthestapesinthecaseoftheintactossicularchain,aftercementincusrebuildingandincusinterpositionsarecomparedeachother.Inthisaimanewapproachofossiclesvibrationsobservationisintroducedinordertocompleteinformationobtainedfromclassicalapproachwhichbasesonthetransferfunction.Measurementsofossicularchainvibrationsareperformedonfreshhumantemporalbonespecimenusingthelaserdopplervibrometer.Next,afterclassicalresearch,theextendedanalysiswiththerecurrenceplotstechniqueisperformed.

  • 标签: 技术 中耳 复发 振动测量 情节 估计
  • 简介:

  • 标签:
  • 简介:SeveralREEdatasetswerecollectedinCoreDD2andEC2005intheinnershelfofEastChinaSea,CoreY127inthenorthernOkinawaTrough,CoreNT1,C9247andC92169inthesouthYellowSeatochecktheapplicabilityoftheδEuN-ΣREEsmodelforquantita-tivelydistinguishingsedimentsfromtheYangtzeRiverandtheYellowRiver.Bycomparison,severalsedimentsincoresDD2,EC2005,Y127aregenerallyinaccordancewiththismodel.ThecoresNT1,C9247andC92169,whichhavebeeninfluencedbytheYangtzeRiverandtheYellowRivertogether,however,wereinconsistentwiththeδEuN-ΣREEsmodel.TheδEuN-ΣREEsplotanditscorrespondingregressionequation,whichcouldbeusedtodistinguishsediments"intuitivelyandquantitatively"fromtheYangtzeRiver,andtheYellowRivershouldbereconsideredorreassessed.

  • 标签: rare earths sediment PROVENANCE YANGTZE RIVER
  • 简介:Background:Ecologistsareinterestedinassessingthespatialandtemporalvariationinecologicalsurveysrepeatedovertime.Thispapercomparesthe1985and2015surveysoftheBarroColoradoForestDynamicsplot(BCI),Panama,dividedinto1250(20m×20m)quadrats.Methods,spatialanalysis:TotalbetadiversitywasmeasuredasthetotalvarianceoftheHellinger-transformedcommunitydatathroughouttheBCIplot.Totalbetawaspartitionedintocontributionsofindividualsites(LCBDindices),whichweretestedforsignificanceandmapped.Results,spatialanalysis:LCBDindicesindicatedthesiteswithexceptionalcommunitycomposition.In1985,theyweremostlyfoundintheswamphabitat.Inthe2015survey,noneoftheswampquadratshadsignificantLCBDs.Whathappenedtothetreecommunityintheinterval?Methods,temporalanalysis:Thedissimilarityincommunitycompositionineachquadratwasmeasuredbetweentime1(1985)andtime2(2015).TemporalBetaIndices(TBI)werecomputedfromabundanceandpresence-absencedataandtestedforsignificance.TBIindicescanbedecomposedintoB=species(orabundances-per-species)lossesandC=species(orabundances-per-species)gains.B-Cplotswereproduced;theydisplayvisuallytherelativeimportanceofthelossandgaincomponents,throughtime,acrossthesites.Results,temporalanalysis:InBCI,quadratswithsignificantTBIindiceswerefoundintheswamparea,whichisshrinkinginimportanceduetochangestothelocalclimate.ApublishedhabitatclassificationdividedtheBCIforestplotintosixhabitatzones.GraphsoftheBandCcomponentswereproducedforeachhabitatgroup.Group4(theswamp)wasdominatedbyspecies(andabundances-per-species)gainswhereasthefiveotherhabitatgroupsweredominatedbylosses,somegroupsmorethanothers.Conclusions:WeidentifiedthespeciesthathadchangedthemostinabundancesintheswampbetweenT1andT2.Thisanalysissupportedthehypothesisthattheswampisdryingoutandisinvadedbyspeciesfr

  • 标签: BETA DIVERSITY B-C PLOTS BCI forest