简介：Overthepastfewdecades,extremechangeshaveoccurredinthecharactersofexploitedfishpopulations.Themajorityofthesechangeshaveaffectedthegrowthtraitsoffishlifehistory,whichincludeasmallersize-at-age,anearlierage-at-maturationandamongothers.Currently,thecausesoftheselifehistorytraitschangesstillrequiresystematicanalysesandempiricalstudies.Theexplanationsthathavebeencitedaremerelyexpressedintermsoffishphenotypicadaptation.Ithasbeenclaimedthattheoriginaltraitsoffishcanberecoveredoncetheintensityofexploitationofthefishiscontrolled.Sustainedenvironmentalandfishingpressurewillchangethelifehistorytraitsofmostfishspecies,sothefishindividual’straitsarestillinsmallsize-at-ageandatearlierage-at-maturationinexploitedfishpopulations.Inthispaper,weexpressedourviewofpointsthatfishinggearhasimposedselectivityonfishpopulationsandindividualsasvariousotherenvironmentalfactorshavedoneandsuchchangesareunrecoverable.Accordingtotheexistingtendofexploitedfishindividual’slifehistorytraits,wesuggestedfurtherresearchesinthisfieldandprovidedbettermethodsoffisherymanagementandtherebyfisheryresourcesprotectionthanthoseavailableearly.

简介：Afatiguelifeestimationmethodforoffshorestructuresunderrandomstressresponseisstudiedinthispaper.Themethodofbroadbandcumulativefrequencynumberisusedtodeterminetheeffectofbandwidthofstressfrequencyspectraonfatigue.AformulaofcorrectionfactorforfatigueunderbroadbandstressspectraissuggestedandcomparedwiththatgivenbyP.H.Wirsching.

简介：-Withtherapiddevelopmentoftheoffshoreoilindustries,submarineoil/gaspipelineshavebeenwidelyused.Underthecomplicatedsubmarineenvironmentalconditions,thedynamiccharacteristicsofpipelinesshowsomenewfeaturesduetotheexistenceofbothinternalandexternalflows.Thepaperisintendedtoinvestigatethevortex-inducedvibrationofthesuspendedpipelinespanexposedtosubmarinesteadyflow.Especially,theeffectsoftheflowinsidethepipelinearetakenintoaccount.Itsinfluencesontheamplitudeofpipelineresponse,andthenonthefatiguelife,aregivenintermsofthevelocityoftheinternalflow.

简介：Shelf-lifeextensionofaquaticproductsisofsignificanteconomicalimportance.Todeterminethepotentialeffectofchitosanontheshelf-lifeoffilletedtilapia,thisstudyanalyzedthebacterialcommunitydiversityinfreshandspoiledtilapiafilletsstoredat(4±1)℃andexaminedtheantimicrobialactivityofchitosanagainstrelevantbacteriaisolates.ResultsshowedthatPseudomonas(20%)andAeromonas(16%)wereabundantinfreshtilapiafillets,whereasPseudomonas(52%),Aeromonas(32%)andStaphylococcus(12%)weredominantinthespoiledsamples.Chitosanshowedwide-spectrumantibacterialactivityagainstbacteriaisolatedfromtilapiaand5.0gL-1chitosanwasselectedforapplicationinpreservation.Wefurtherdeterminedtheshelf-lifeofchitosan-treated,filletedtilapiastoredat(4±1)℃basedonmicrobiological,biochemicalandsensoryanalyses.Resultsshowedthattheshelf-lifeofchitosan-treated,filletedtilapiawasextendedto12d,whereasthatofuntreated,controlsampleswas6d.Theseindicatethatchitosan,asanaturalpreservative,hasgreatapplicationpotentialintheshelf-lifeextensionoftilapiafillets.