简介:Intheestimationofseismictendency,usingGutenberg-Richter¢sb-valueandusingHurstexponentaretwocom-monlyusedmethods.Basedonthefractalgeometryofearthquaketimeseries,wepointoutthatthesetwomethodscorrelatetoeachother.IntheperspectiveoffractionalBrownianmotion(FBM),anearthquakesequencewithb>3/4andthatwithb<3/4havedifferentdynamicproperties.
简介:WeusedearthquakecatalogsrecordedbyGuangdongSeismologicalNetworkfrom2008to2014toresolvethespatialvariationsofb-valuesinthecoastalareaofGuangdong,particularlyinthreekeyresearchareas(Yangjiang,Heyuan,andoffshoreNanaoIsland)withstrongseismicity.Ourresultsrevealedthatb-valuesexhibitedsignificantspatialvariations,andzoneswithlowb-valuescouldindicatethemostlikelyseismogenicareaoflargeearthquakes.Weobservedthreeclearlowb-valuepatchesintheoffshoreNanaoIsland.Wefoundadistincthighb-valuepeakatthedepthof11kmandtwominimumpeaksatabout14and7–8kmintheYangjiangarea.Theoverallb-valuesgenerallydecreasewithdepthintheHeyuanarea.Thespatialvariationsofb-valuesreflecttectonicanomalies;thatis,the‘low-high-low’distributionofb-valuesintheoffshoreNanaoIslandandtheYangjiangareamayindicatetheanomalyofthecrustalstructurewithaweaklayer.Theb-valuesofreservoir-inducedseismicityareobviouslylowerthanthatinducedbytectonism.Thisfindingindicatesthatthereservoirareaisgenerallyathighstressstateundertheconditionofhighporepressure.Weinferredthatlargeearthquakesmightbepronetooccurat10–12kmdepthintheoffshoreNanaoIsland,at12–15kmdepthintheYangjiangarea,andatthelowerpartoftheseismicactivityzoneintheHeyuanarea.Moreover,theupstreamareaoftheXinfengjiangreservoiristhemostlikelyareaoffuturelargeearthquakesintheHeyuanarea.
简介:SequencevariationofpartialcytochromebgenesbetweentwoCoiliaspecies,C.ectenesandC.mystus,wasinvestigated.Ofthe402nucleotides,twenty-seven(6.72%)arepolymorphicandallaresynonymoussubstitutions.Atthethirdpositionsofgeneticcondonofcytochromebgene,thetwospeciesshowanextremeanti-Gbias(<4%)andapronouncedbiastowardsAandC(>68%).Thereisnoaminoacidsequencedivergencebetweenthepartialcytochromebgenesofthetwospecies,indicatingaclosegeneticrelationshipbetweenthem.Thek-2pgeneticdistanceofpartialcytochromebsegmentofthetwospeciesis0.072,suggestingthatthespecieswereseparated3.6Maago,inthemiddlePliocene.Ourresultrevealsthatthecytochromebgeneisanappropriatemarkerforstudiesofpopulationgeneticstructuresandphylogeographicpatternsofthetwospecies.
简介:Effectsofthemixtureofβ-ecdysoneandpolypodine-B(2:1W/W)onthemoultingandgrowthofprawn,Penaeusorientalisswerestudiedinlaboratorybyrearingtheanimalwiththeaddedcompounddiets.Theresultsshowedthattheadditionofthemoultinghormone(M.H)mixturetocompounddiets,from1.33×10-6to30×10-6,couldincreasemoultingactivityandgrowthrateoftheprawntodifferentextents,amongwhichthe5.33×10-6-10.67×10-6additionhadstatisticallysignificanteffects.However,60×10-6addeddietscausedmoultingandgrowthinhibitionsandcuticlethickening.Theanalysesofprotein,waterandashcontentsoftheprawnshowednoremarkabledifferencesbetweenhormonedosedanimalsandthecontrol.