简介:Background:Oneofthemostimportantdriversofforestbiodiversityisconspecificnegativedensitydependence(CNDD),areductioninperformancewhenconspecificdensitiesarehigh.WhilethemajorityofCNDDresearchhasfocusedontropicalforests,evidenceismountingthatCNDDmayalsoplayanimportantroleintemperateforests.Tofurtherexplorethepotentialreachofthisphenomenon,weinvestigatedCNDDinAmericanbeech(Fagusgrandifolia)inamaturemid-Atlanticforest.Methods:Weusedbivariatepointpatternanalysestoexaminespatialrelationshipsbetweenlargebeechtreesandconspecificsaplings,andwealsocontrastedthesepatternswithcomparablepatternsforheterospecifics.Inaddition,toaddressthepossibilityofdispersallimitationandtheassociatedeffectsonspatialpatterns,weanalyzedseedlingdensityasafunctionofadultconspecificabundance.Results:Wefoundthatbeechsaplingsweremorerepeledfromlargeconspecificsthanlargeheterospecifics,despitethefactthatbeechseedlingdensitywaspositivelycorrelatedwithbeechbasalarea.However,saplingsofothercanopytreespecieswerealsorepeledfromadultbeechtrees,suggestingageneralsuppressiveeffect.Nonetheless,thediscrepancybetweenbeechseedlingandsaplingdensitiesbeneathadultconspecificssuggeststhatbeechseedlingsurvivalrateswerereducedinvicinityofconspecificadults.Conclusions:Regardlessoftheextenttowhichbeechinhibitsheterospecifictrees,anegativeeffectonconspecificrecruitsmaybecriticalforbiodiversitymaintenance.Withoutthisconspecificsuppression,adenselayerofshade-tolerantbeechsaplingscouldformbeneathadultbeechtrees.Ifthisweretooccur,beechwouldhaveasubstantialhead-startfolowingcanopydisturbance,andthislate-successionalspeciescouldpotentialydominateastandinperpetuity,throughrepeateddisturbancecycles.
简介:ThecompleteopenreadingframeofOsPIN1awasamplifiedthroughreversetranscriptase-polymerasechainreaction(RT-PCR)basedonthesequencedepositedinGenBanktoexploretherelationshipbetweentheauxineffluxproteinOsPIN1aandthenegativephototropismofriceroots.SequencingresultsshowedthattheGCcontentofOsPIN1awas65.49%.ThefusionexpressionvectorpCAMBIA-1301-OsPIN1a::GFPcontainingtheOsPIN1ageneandacodinggreenfluorescentprotein(gfp)genewasconstructed.ThefusionvectorwastransferredintoonionepidermalcellsbyAgrobacteriumtumefacienstransformation.ThetransientexpressionofOsPIN1a-GFPwasmainlylocatedinthenucleusandcellmembrane.Moreover,thetransgenicplantswereobtainedbyAgrobacterium-mediatedgenetictransformation.MoleculardetectionperformedbyusingPCRandβ-glucuronidasestainingshowedthatthetargetconstructwasintegratedintothegenomeofrice.Thenegativephototropiccurvaturesofthetransgenicricerootswerehigherthanthoseofthewildtype.Similarly,theexpressionlevelsofOsPIN1ainthetransgenicplantswereconsiderablyhigherthanthoseinthewild-typeplants.TheseresultssuggestthatOsPIN1aiscrucialinthenegativephototropiccurvatureofriceroots.
简介:Thisstudywasonsuperiorityofthenon-negativematrixfactorization(NMF)algorithmforapplicationofinformationextractedwithaerialimages.First,NMFwasusedforaerialimageinformationextraction,andthenthisdatawascomparedwithaprincipalcomponentanalysis(PCA)inwhichr(thenumberofrowsorcolumnsofbasicmatrix)andEignum(thenumberofeigenvalues)weregivendifferentvalues.ExperimentalresultsshowedthattheruntimeofNMFwithr=20or50waslessthanthatofPCAwithanEignum=20or50.Also,therecognitionrateofNMFwithr=50washigherthanthatofanEignum=50.Theexperimentshowedthatnonnegativematrixfactorizationhadadvantagesofashorttimeperiodwithahighrecognitionrate.
简介:APoissonregressionmodelandanegativebinomialregressionmodel(NBmodel)areoftenusedinareassuchasmedicineandeconomy,butrarelyinthedomesticforestrysector,especiallyintheforestfireforecasting.BasedonthedataofforestfireoccurrencesinDaxing’anlingregionin1980-2005,thispaperprofoundlyanalyzestheapplicationconditionsandtestmethodsofthetwomodels.TheAICmethodwasusedtocheckthefittinglevelofthemodelsandthecapabilityofthemodelsforforecastingforestfireswasdiscussed.ThisstudyprovidednecessarytheoreticalbasisanddatasupportfortheapplicationofthetwomodelsinthefieldofforestryinChina.