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宝石和宝石学杂志(中英文) 1989年第1期 103-103,88页

作者： m.mitchell Waldrop 杨铁汾

尽管尘埃很糟糕,但来自白垩—第三纪撞击的化学散落物却是更糟的——非常糟的。

关键词：第三系岩石第三纪酸雨酸性降水降雨淋滤

Assessing the utility of the tipping point ratio to monitor HIV treatment programmes in the era of universal access to ART

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Infectious Disease modelling 2018年第1期3卷 85-96页

作者： Simon de montigny marie-Claude Boily Benoît Rmasse Kate m.mitchell Dobromir T.Dimitrov CHU Sainte-Justine Research Center MontrealQCCanada School of Public Health University of MontrealMontrealQCCanada Department of Infectious Disease Epidemiology Imperial CollegeLondonUnited Kingdom Fred Hutchinson Cancer Research Center SeattleWAUnited States

Background:The epidemiological tipping point ratio(TPR)has been suggested as a useful indicator to monitor the scale-up of antiretroviral treatment(ART)programmes and determine when scale-up is sufficient to control the *** has been defined as the ratio of yearly number of new HIV infections to the yearly number of new ART initiations or to the yearly net increase in the number of people on *** has been used to rank the progress of treatment programmes across countries,with the objective of reaching a TPR value under *** study aims to assess if TPR alone can be used as an indicator of ART success across settings by comparing the expected changes in HIV incidence and ART coverage when TPR is maintained constant over *** particular,we focus on the effect of ART initiation timing(emphasis on ART being initiated early or late during HIV progression)on the interpretation of the ***:We used a dynamic model of HIV transmission in South Africa representing ART rollout leading to universal treatment in *** model is calibrated to HIV incidence,HIV prevalence and ART coverage in 2012 in South Africa,and 1000 simulations are selected for the base-case *** measure the effect of TPR,we simulate TPRpreserving interventions,maintaining TPR(yearly number of new ART initiations denominator)at the value observed in 2019(between 0.65 and 1.25)for 15 *** compare ART coverage and HIV incidence across TPR values and across strategies in which ART access is prioritized *** a secondary analysis,we illustrate the sensitivity of new ART initiations to ART retention,and we compare both definitions of the ***:Our analysis shows that HIV incidence reduction is weakly correlated to TPR:the same reduction in HIV incidence(15%)can be achieved by implementing the same strategy with a wide range of TPR maintained(0.65e1.12).Assuming high retention in ART,TPR-preserving strategies prioritizing early ART initiation yield greater reduction i

关键词： treatment maintained retention

marsh persistence under sea-level rise is controlled by multiple,geologically variable stressors

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Ecosystem Health and Sustainability 2017年第10期3卷 22-38页

作者： m.mitchell J.Herman D.m.Bilkovic C.Hershner Virginia Institute of marine Science College of William&MaryGloucester PointVAUSA

Introduction:marshes contribute to habitat and water quality in estuaries and coastal *** importance to continued ecosystem functioning has led to concerns about their ***:Concurrent with sea-level rise,marshes are eroding and appear to be disappearing through ponding in their interior;in addition,in many places,they are being replaced with shoreline stabilization *** examined the changes in marsh extent over the past 40 years within a subestuary of Chesapeake Bay,the largest estuary in the United States,to better understand the effects of sea-level rise and human pressure on marsh ***:Approximately 30 years ago,an inventory of York River estuary marshes documented the historic extent of *** were resurveyed in 2010 to examine shifts in tidal marsh extent and *** change varied spatially along the estuary,with watershed changes between a 32%loss and an 11%gain in marsh *** of marsh was apparent in high energy sections of the estuary while there was marsh gain in the upper/riverine section of the estuary and where forested hummocks on marsh islands have become *** showed little change in the small tributary creeks,except in the creeks dominated by fringing marshes and high shoreline ***:Differential resilience to sea-level rise and spatial variations in erosion,sediment supply,and human development have resulted in spatially variable changes in specific marsh extents and are predicted to lead to a redistribution of marshes along the estuarine gradient,with consequences for their unique communities.

关键词： Chesapeake Bay climate change coastal resilience marsh change salt marsh sea-level rise tidal wetlands

Using data from‘visible’populations to estimate the size and importance of‘hidden’populations in an epidemic:A modelling technique

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Infectious Disease modelling 2020年第1期5卷 798-813页

作者： Anna m.Foss Holly J.Prudden Kate m.mitchell michael Pickles Reynold Washington Anna E.Phillips michel Alary marie-Claude Boily Stephen moses Charlotte H.Watts Peter T.Vickerman Department of Global Health and Development and Centre for mathematical modelling of Infectious Diseases London School of Hygiene and Tropical Medicine15-17 Tavistock PlaceLondonWC1H 9SHUK Department of Infectious Disease Epidemiology School of Public HealthImperial College LondonMedical School BuildingSt Mary’s CampusNorfolk PlaceLondonW21PGUK St John’s Research Institute 100 Feet RoadJohn NagarKoramangalaBangalore560034KarnatakaIndia Department of Community Health Sciences Max Rady College of MedicineRady Faculty of Health SciencesUniversity of ManitobaS113-750 Bannatyne AvenueWinnipegManitobaR3E 0W3Canada Centre de recherche du CHU de Québec-UniversitéLaval 1050 Chemin Ste-FoyQuébec(Qc)G1S 4L8Canada Département de médecine sociale et préventive Facultéde médecineUniversitéLaval1050avenue de la MédecineQuébec(Qc)G1V 0A6Canada

We used reported behavioural data from cisgender men who have sex with men and transgender women(mSm/TGW)in Bangalore,mainly collected from‘hot-spot’locations that attract mSm/TGW,to illustrate a technique to deal with potential issues with the representativeness of this sample.A deterministic dynamic model of HIV transmission was developed,incorporating three subgroups of mSm/TGW,grouped according to their reported predominant sexual role(insertive,receptive or versatile).Using mathematical modelling and data triangulation for‘balancing’numbers of partners and role preferences,we compared three different approaches to determine if our technique could be useful for inferring characteristics of a more‘hidden’insertive mSm subpopulation,and explored their potential importance for the HIV *** for 2009 across all three approaches suggest that HIV prevalence among insertive mSm was likely to be less than half that recorded in the surveys(4.5e6.5%versus 13.1%),but that the relative size of this subgroup was over four times larger(61e69%of all mSm/TGW versus 15%).We infer that the insertive mSm accounted for 10e20%of all prevalent HIV infections among urban males aged *** modelling can be used with data on‘visible’mSm/TGW to provide insights into the characteristics of‘hidden’mSm.A greater understanding of the sexual behaviour of all mSm/TGW is important for effective HIV *** broadly,a hidden subgroup with a lower infectious disease prevalence than more visible subgroups,has the potential to contain more infections,if the hidden subgroup is considerably larger in size.

关键词： HIV Infectious diseases mathematical modelling men who have sex with men Transgender women India

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一种新型弹性体材料—SEP

橡胶参考资料 1987年第1期 13-19页

作者： Julian m.mitchell 王启生

引言在许多热固性塑料或热塑性塑料的应用中,为了调节和满足加工性能或使用性能的要求,常常对两种或两种以上的聚合物进行并用。在制造轮胎和橡胶工业制品方面,所选择的主要是使聚烯烃改性,以改善冲击强度和热塑性弹性体的结构。目前,... 详细信息

引言在许多热固性塑料或热塑性塑料的应用中,为了调节和满足加工性能或使用性能的要求,常常对两种或两种以上的聚合物进行并用。在制造轮胎和橡胶工业制品方面,所选择的主要是使聚烯烃改性,以改善冲击强度和热塑性弹性体的结构。目前,聚合物并用技术已扩展到更加广泛的应用领域,它作为一条切实可行的技术路线,相当引人注

关键词： SEP 橡胶弹性体并用胶过氧化物硫化扯断伸长率硫黄抗张强度扯断强度促进剂硫化胶胶料耐压强度体积电阻低温屈挠物理性能电性能

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生命真的开始于RNA世界吗?

世界科学 1993年第8期 26-28页

作者： m.mitchell Waldrop 李庆

混沌初开,地球上的原始生物还没进化出蛋白质或遗传密码的时候,复杂而万能的RNA分子(核糖核酸)控制着生物体的基础化学。地球上的每一点遗传信息都被编入RNA中。细胞新陈代谢中发生的一切化学反应都由RNA来催化。大约40亿万年前的原始... 详细信息

混沌初开,地球上的原始生物还没进化出蛋白质或遗传密码的时候,复杂而万能的RNA分子(核糖核酸)控制着生物体的基础化学。地球上的每一点遗传信息都被编入RNA中。细胞新陈代谢中发生的一切化学反应都由RNA来催化。大约40亿万年前的原始地球是一个“RNA世界”。上述观点已成为人们的常识。80年代初,当科罗拉多大学的托马斯·舍契(Thomas Cech)和耶鲁大学的西德尼·沃尔曼(Sidney Alman)证

关键词：学说乔伊斯生命欧格尔 RNA 生命起源遗传信息同分异构体

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人工智能——仿造人类的思维

世界科学 1986年第4期 40-43页

作者： m.mitchell Waldrop 丁鸿富

经过三十年艰苦的工作以后,人工智能正成熟起来,正从实验室走向市场。专家系统,即能够像人类的专家一样给出建议的计算机程序,已经能够确定矿藏位置,为病人诊断。程序已经可以做到相当灵巧地理解通俗的英语或法语。机器人不久就可以借... 详细信息

经过三十年艰苦的工作以后,人工智能正成熟起来,正从实验室走向市场。专家系统,即能够像人类的专家一样给出建议的计算机程序,已经能够确定矿藏位置,为病人诊断。程序已经可以做到相当灵巧地理解通俗的英语或法语。机器人不久就可以借助于计算机视觉系统,把一个物体或场面的数字化照片储存起来,还可以相当准确地“认出”照片上有些什么。

关键词：人工智能研究者计算机程序人类