简介:摘要位移公式是高中物理运动学部分中比较重要的公式,要求学生加深对公式的理解和掌握。本文对位移公式S=1/2at2及S=V0t+1/2at2阐述了一些新见解,以供广大同仁参考。
简介:目的探讨特勤人员S_ⅠS_ⅡS_Ⅲ综合征特点。方法选取Ⅰ、Ⅱ、Ⅲ标准导联同时存在S波的患者心电图,分析Ⅰ、Ⅱ、Ⅲ、aVR、V1、V5导联R波与S波比值、心电轴及年龄、体型以及病史等相关参数。结果(1)S_ⅠS_ⅡS_Ⅲ综合征发生率低,仅0.9%(51/5639人);(2)51例S_ⅠS_ⅡS_Ⅲ综合征患者心电轴偏移范围宽,在-110°~+178°,平均(27.49±79.74)°,其中心电轴正常19例(37.3%)、右偏15例(29.4%)、左偏13例(25.5%)、心电轴不确定4例(7.8%);(3)S_ⅠS_ⅡS_Ⅲ综合征多见于体质量指数偏低即呈瘦长体型年轻人,体质量指数〈24.0者占58.8%(30/51);(4)疗养体检无其他异常发现。结论健康特勤人员可出现S_ⅠS_ⅡS_Ⅲ综合征,多见于瘦长体型年轻人,可能系正常心电图变异,但诊断要慎重,须经心脏超声及X射线等检查排除器质性疾病。
简介:Deterrenceandcoercionaretwokindsofstrategies,thelatterbeingmoreaggressivethantheformer.TheU.S.Asia-PacificRebalancingstrategyisanimportantdiplomaticlegacyofObama'sadministration.FortheissuesinvolvingtheDiaoyuIslands,theSouthChinaSea,cybersecurity,DPRK'snuclearprogram,andIran'snuclearprogram,theU.S.hascarriedoutmilitarydeterrenceandnon-forcecoercionagainstChina.Butgenerally,thesearelow-levelcoercivemeasuresanddistinctfromthesevereeconomicsanctionanddiplomaticisolationimposedbytheU.S.onRussia,Syria,DPRKandIraninrecentyears.ConcerningissueswheretheU.S.andChinaholddistinctviews,therewouldbelessstrategicleewayforthetwocountries.IftheU.S.istostrengthendeterrenceandcoerciontowardsChina,Chinacanrespondmoreactivelyandeffectively,butitwillbemoredifficulttobuildanewmodelofChina-U.S.major-countryrelationship.
简介:Neurotrophicfactorscompriseessentialsecretedproteinsthathaveseveralfunctionsinneuralandnon-neuraltissues,mediatingthedevelopment,survivalandmaintenanceofperipheralandcentralnervoussystem.Therefore,neurotrophicfactorissuehasbeenextensivelyinvestigatedintothecontextofneurodegenerativediseases.Alzheimer'sdiseaseandParkinson'sdiseaseshowchangesintheregulationofspecificneurotrophicfactorsandtheirreceptors,whichappeartobecriticalforneuronaldegeneration.Indeed,neurotrophicfactorspreventcelldeathindegenerativeprocessesandcanenhancethegrowthandfunctionofaffectedneuronsinthesedisorders.Basedonrecentreports,thisreviewdiscussesthemainfindingsrelatedtotheneurotrophicfactorsupport–mainlybrain-derivedneurotrophicfactorandglialcellline-derivedneurotrophicfactor–inthesurvival,proliferationandmaturationofaffectedneuronsinAlzheimer'sdiseaseandParkinson'sdiseaseaswellastheirputativeapplicationasnewtherapeuticapproachforthesediseasesmanagement.