简介:Thepeculiarattributesofmusclesthatarestretchedwhenactivehavebeennotedfornearlyacentury.Understandably,thefocusofmusclephysiologyhasbeenprimarilyonshorteningandisometriccontractions,aseloquentlyrevealedbyA.V.Hillandsubsequentlybyhisstudents.WhentheslidingfilamenttheorywasintroducedbyA.F.HuxleyandH.E.Huxley,itwasarelativelysimpletasktolinkHill'smechanicalobservationstotheactionsofthecrossbridgesduringtheseshorteningandisometriccontractions.Incontrast,lengtheningoreccentriccontractionshaveremainedsomewhatenigmatic.Dismissedasnecessarilycausingmuscledamage,eccentriccontractionshavebeenmuchmoredifficulttofitintothecross-bridgetheory.Therelativelyrecentdiscoveryofthegiantelasticsarcomericfilamenttitinhasthrustapreviouslymissingelementintoanydiscussionofmusclefunction,inparticularduringactivestretch.Indeed,theunexpectedcontributionofgiantelasticproteinstomusclecontractilefunctionishighlightedbyrecentdiscoveriesthattwitchin-actininteractionsareresponsibleforthe"catch"propertyofinvertebratemuscle.Inthisreview,weexamineseveralcurrenttheoriesthathavebeenproposedtoaccountforthepropertiesofmuscleduringeccentriccontraction.Weaskhowwelleachoftheseexplainsexistingdataandhowanelasticfilamentcanbeincorporatedintotheslidingfilamentmodel.Finally,wereviewtheincreasingbodyofevidenceforthebenefitsofincludingeccentriccontractionsintoaprogramofmusclerehabilitationandstrengthening.
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:ChangesoftherelationshipbetwenpopulationandenvironmentintheYangtzeRiverValeyinhistoryZHANGDixiangSUNPingThePopulationResearch...
简介:AttheinvitationoftheChineseAssociationForInternationalUnderstanding(CAFIU),a7-memberdelegationoftheInternationalInitiativesofChangeAssociationofJapan(IICAJ)headedbyToruHashimoto,AdvisorofJapanMizuhoFinancialGroup,PresidentoftheJapaneseBranchoftheDeustchBankGroupandPresidentoftheIICAJvisitedChinafromOctober10to16,2004.
简介:AbstractRecently, death from herpes B virus (Cercopithecine Herpesvirus 1) infection was reported in China, reminding us to be alert to the risk of transmission and infection with herpes B virus. Herpes B virus is a zoonotic pathogen that can cause fatal encephalomyelitis in humans. The virus naturally infects rhesus monkeys, causing diseases like human herpes simplex virus (HSV) infection, which are often asymptomatic or mild in the rhesus macaque. However, herpes B virus infection can be fatal to humans. Without timely treatment, the mortality rate of herpes B virus infection is as high as 70%-80%. To date, approximately 50 cases of human herpes B virus (HBV) infection have been reported worldwide. Most cases are related to direct contact with macaques, such as scratching, biting, or mucosal contact with monkey body fluids or secretions. Although the risk of human-to-human transmission is low, the widespread prevalence of the virus among monkeys, the high mortality of infected persons, and the severe neurological sequelae of survivors render this virus an important zoonotic pathogen that threatens human beings. Biorisk-related training programs for at risk personnel and timely treatment after exposure to the B virus can reduce infection rate and mortality. The early initiation of antiviral therapy prevents severe disease or death after the rapid diagnosis of human B virus disease. Identification of risk factors is essential in controlling the spread of the herpes B virus in the population at risk.
简介:AbstractVisualization and access. Historically, these have been the two major factors that have limited advancement in the field of Otolaryngology. No other surgical specialty deals with anatomical challenges quite like those presented by the structures of the head and neck. Otolaryngology is a field of dark cavities, complex and miniscule structures, and awkward angles. The aim of this article is to briefly explore how Otolaryngologists have historically met these challenges, with a specific focus on technological advancements in illumination, visualization, and access. From mirrors reflecting candlelight to fiberoptic illuminated scopes, from bamboo nasal speculums to Transoral Robotic Surgery (TORS), tracing the historical arc of these technologies highlights the innovative spirit that has come to define the field of Otolaryngology.
简介:BasedonhistoricaldocumentsandrecordsthispaperanalyzesthecharacteristicsoffrequencyanddistributionofmajordisastersthattookplaceinthehistoryofChina.Thefindingsshowthatoccurrencesofdifferenttypesofdisastersvariedandspatialpatternatprovinciallevelaresignificantlydifferentaswell.Theresultsalsoindicatethatthereisastrongrelationshipbetweentypeofdisastersandspatialdistributionandthatthespatialpatternoflosseswasnotthesameasthatofthefrequency.Thereasonsare:(1)thehazard-formativeenvironmentswhich,toalargeextent,determinethespatialpatternofthedisastersaresignificantlydifferent;(2)thelossescausedbynaturaldisasterswerecloselyrelatedtotheconcentrationofeconomyandpopulation.Numberofdeathswasusuallylargeinareaswhereagriculture,cultureandbusinesswererelativelydeveloped.ThespatialpatternofdisasterlossesisanevitableresultofuneveneconomicdevelopmentinthehistoryofChina.
简介:Background:Nationalforestresourceassessmentsandmonitoring,commonlyknownasNationalForestInventories(NFI’s),constituteanimportantnationalinformationinfrastructureinmanycountries.Methods:ThisstudypresentsdetailsaboutdevelopmentsoftheNFIinChina,includingsamplingandplotdesign,andtheusesofalternativedatasources,andspecifically·reviewstheevolutionofthenationalforestinventoryinChinathroughthe20thand21stcenturies,withsomereferencetoEuropeandtheUS;·highlightstheemergenceofsomecommoninternationalthemes:consistencyofmeasurement;moreefficientsamplingdesigns;implementationofimprovedtechnology;expansionofthevariablesmonitored;scientifictransparency;·presentsanexampleofhowChina’sexpandingNFIexemplifiestheseglobaltrends.Results:MainresultsandimportantchangesinChina’sNFIaredocumented,bothtosupportcontinuedtrendanalysisandtoprovidedatauserswithhistoricalperspective.Conclusions:NewtechnologiesanddataneedsensurethattheChineseNFI,likethenationalinventoriesinothercountries,willcontinuetoevolve.Withinthecontextofhistoricalchangeandcurrentconditions,likelydirectionsforthisevolutionaresuggested.
简介:ThebrieftheoriesofwaveletanalysisandHilbert-Huangtransform(HHT)areintroducedfirstlyinthepresentpaper.ThenseveralsignaldatawereanalyzedbyusingwaveletandHHTmethods,respectively.ThecomparisonshowsthatHHTisnotonlyaneffectivemethodforanalyzingnon-stationarydata,butalsoisausefultoolforexaminingdetailedcharactersoftimehistorysignal.