The global impact of HIV/AIDS

The scale of the human immunodeficiency virus (HIV)/AIDS epidemic has exceeded all expectations since its identification 20 years ago. Globally, an estimated 36 million people are currently living with HIV, and some 20 million people have already died, with the worst of the epidemic centred on sub-Saharan Africa. But just as the spread of HIV has been greater than predicted, so too has been its impact on social capital, population structure and economic growth. Responding to AIDS on a scale commensurate with the epidemic is a global imperative, and the tools for an effective response are known. Nothing less than a sustained social mobilization is necessary to combat one of the most serious crises facing human development.     

The spread of HIV-1 in Africa: sexual contact patterns and the predicted demographic impact of AIDS

The spread of HIV-1 in Africa is examined here in the light of recent information on the main epidemiological and behavioural determinants of transmission. Mathematical models incorporating demographic, epidemiological and behavioural processes are used to assess the potential demographic impact of the disease AIDS. These analyses highlight the significance of patterns of sexual behaviour, and in particular networks of sexual contact, on the predicted spread of infection. Current data reveal substantial variations in the degree of spread between and in countries, but new analyses support earlier predictions that in the worst-afflicted areas AIDS is likely to change population growth rates from positive to negative values in a few decades.     

基于GM(1,1)模型的平顶山市劳动力人口供给预测

现阶段中国人口存在总量增长、老龄化加速与劳动力下降以及地域不平衡性的特点.以平顶山市劳动力人口变化趋势为研究对象,运用短维灰色GM(1,1)模型进行平顶山市劳动年龄人口预测,运用线性回归进行平顶山市劳动参与率分析,并建立平顶山市劳动力人口预测模型,最终预测2010—2019年平顶山市劳动力人口供给情况.结果表明:以15~64岁为统计口径的平顶山市劳动力人口在2010—2019年间将保持平稳缓慢增长状态,年均增长速度约为0.4%,尚未出现劳动力短缺拐点.     

Incubation period of AIDS in patients infected via blood transfusion

Temporal trends in the prevalence of HIV (human immunodeficiency virus) infection are uncertain because of the reluctance of most governments to embark on large-scale programmes of serological surveillance. In the absence of such data, attempts have been made to relate the number of reported cases of AIDS (acquired immune deficiency syndrome) in a defined population to the proportion of that population infected with the virus as a specified time point. One crucial determinant of this relationship is the probability distribution of the incubation period of the disease, with the period defined as the time interval from infection to diagnosis. Recent statistical analysis suggests a mean incubation period of 4.5 years with wide confidence limits, whereas a more heuristic study reports a mean of 15 years. Here we report on a new analysis which reveals age-related differences in the mean (and median) incubation period: 1.97 (1.90) years for children (0-4 yrs old at infection), 8.23 (7.97) years for adults (5-59 yrs old), 5.50 (5.44) years for elderly patients (60 yrs and older).     

冷箭竹竹笋种群消长规律

研究了冷箭竹（Ｂａｓｈａｎｉａｆａｎｇｉａｎａ）无性系繁殖竹笋的种群消长规律；建立了冷箭竹活笋数、死笋数、总发笋数的消长预测模型；找出影响冷箭竹种群消长的主要因素；得出当年生活笋数与一年生成竹数对第２年的成活竹笋数有显著影响，二年生与多年生成竹数对第２年的死笋数有显著影响的结论．了解冷箭竹的种群发展和竹种资源数量是预测对大熊猫承载能力的科学依据．     

北京 MSM 人群 HIV 传播的贝叶斯推断

从北京地区收集了 44 例年轻男男同性恋 (men who have sex with men, MSM) 性行为者的人类免疫缺陷病毒 (human immunodeficiency virus, HIV)-1 基因序列, 利用贝叶斯推断从中提取了一些有价值的流行病学信息, 得到了传播动力学的重要参数: 有效再生数 $R_{\rm e}$. 研究结果显示, 2006 年至 2014 年 HIV/AIDS (acquired immune deficiency syndrome) 的传播速度明显加快, 这可能与过去十多年间中国年轻人群对男男同性恋人群的接受程度越来越高有关. 结果揭示了近十多年来 HIV/AIDS 在北京 MSM 中的传播趋势. 这些信息可以为疫情预测及制定干预措施提供帮助.     

对高危人群实施干预措施的时滞HIV/AIDS传播模型

考虑了一类对高危人群实施干预措施的HIV/AIDS传播模型,给出了无病平衡点的全局稳定和地方病平衡点局部稳定的条件,当R01时,疾病在人群中持久,同时,研究了干预措施在HIV/AIDS预防中的效果.     

小蓬竹种群结构研究

利用样方调查法,研究了贵州董架乡小蓬竹种群的结构特征。结果表明：小蓬竹无性系种群中1、2年生竹比例超过了50 %,2、4年生竹数量多于1、3年生竹,个体地径主要集中在0400～0698 cm范围内,4～6 m高度级个体数量比例最大。小蓬竹丛平均地径与丛株数大小具有显著的正相关性。由此说明,该种群目前处于增长状态、种群结构基本合理并具有一定的大小年现象,小蓬竹竹丛数量随丛株数的增加呈下降趋势,丛株数为10株以上的竹丛,其平均年龄较为稳定。     

近47年德语区大气科学学科研究方向的变化特征

 为进一步了解国际大气科学发展进程及为中国大气科学学科设置优化调整提供指导，收集整理了1969-2015年德语区7000多篇大气科学学科毕业论文题目，分析了年论文数的时间变化特征，探讨了论文数阶段性增速快慢的原因。结果表明，近47年德语区大气科学类毕业年论文数呈明显的阶段性变化，可分为缓慢增长、较快增长和加速增长3个时期，前两个时期的增速主要与人口增长有关，第三个时期的增速与社会需求、技术革新密切相关；随着大气科学学科分支的细化，从20世纪90年代起，绝大多数研究方向之间的比例差异较20世纪70-80年代有所缩小；近47年，27个研究方向中占比最高的5个研究方向分别是大气探测、应用气象、气候与气候变化、大气物理和动力气象，其中应用气象年论文数的增长速度最快，尤其是近20年增速明显加快，说明大气科学与其他行业的交叉研究在蓬勃发展，并且随着社会需求的提升，这种趋势会进一步加强。     

2000年-2017年中国PM2.5污染的健康影响及经济损失时空分布模式

当今环境下,大气污染是危害人体健康的主要威胁之一,对包括PM2.5在内的细颗粒物污染造成的人群健康影响和经济损失的估算是目前研究的热点之一.该研究采用人口、PM2.5污染浓度等基础数据以及流行病学等相关领域的研究结果,将全国区域划分为5 kmX5 km的精细格网,根据暴露—反应关系函数及统计生命价值法(VSL)、疾病成...     

Aetiology of AIDS--antibodies to human T-cell leukaemia virus (type III) in haemophiliacs

Human T-cell leukaemia virus type III (HTLV-III) is suspected of having a key role in the pathogenesis of acquired immune deficiency syndrome (AIDS). Epidemiological data suggest that AIDS is transmitted by an infectious agent through intimate contact with body secretions, blood or blood products. To maintain haemostasis, many haemophiliac patients depend on commercially prepared clotting concentrates made from large multi-donor plasma pools and are thus at increased risk of developing the disease. We report here that, using indirect membrane immunofluorescence and radioimmunoprecipitation with SDS-polyacrylamide gel electrophoresis, we have detected antibodies to HTLV-III in 30 of 47 (64%) asymptomatic haemophiliacs and in all of three haemophiliacs who either had or soon developed AIDS. Of 34 samples drawn before 1984, 18 (53%) were antibody-positive, whereas of 16 samples drawn during 1984, 15 (94%) were positive (P less than or equal to 0.002). These data suggest that exposure to HTLV-III antigens is widespread among asymptomatic haemophiliacs.     

Conservation biology: lion attacks on humans in Tanzania

Large carnivores inspire opposition to conservation efforts owing to their impact on livestock and human safety. Here we analyse the pattern of lion attacks over the past 15 years on humans in Tanzania, which has the largest population of lions in Africa, and find that they have killed more than 563 Tanzanians since 1990 and injured at least 308. Attacks have increased dramatically during this time: they peak at harvest time each year and are most frequent in areas with few prey apart from bush pigs (Potamochoerus larvatus), the most common nocturnal crop pest. Our findings provide an important starting point for devising strategies to reduce the risk to rural Tanzanians of lion attacks.     

中国就业增长与经济增长的弹性系数分析及对策

改革开放以来,中国经济一直保持较快增长,但近年来就业弹性不断下降,经济增长对就业拉动效应不足问题日益显现,经济结构失衡是就业效应不足的重要诱因。对一个人口大国来说,就业效应不足既是对人力资源的浪费,也会导致大量的社会失业人口的存在,影响社会稳定。必须调整经济结构,在拉动经济增长的同时大力促进就业增长。     

Incubation period of AIDS in San Francisco

In a closed population, the distribution of AIDS diagnoses over time is the convolution of the distributions of human immunodeficiency virus (HIV) infections and the incubation period. This has motivated estimates of the infection distribution, assuming known diagnosis and incubation distributions, but the usefulness of this method is limited by uncertainty about incubation. The large amount of information on the distribution of HIV infections in San Francisco's gay community suggests the opposite approach--estimating the incubation distribution, assuming known infection and diagnosis distributions. A non-parametric implementation of this strategy produced an estimate with a median at 9.8 years, increasing hazard rates, and less uncertainty than previous estimates.     

国内生产总值对建筑业增长影响的计量分析

建筑业产出在很大程度上受到整体经济环境影响。采用序列稳定性检验（ADF）技术、协整检验技术和误差较正模型，分析了中国过去20年间国内生产总值（GDP）增长对建筑业增长影响。发现：中国建筑业与GDP之间有长期稳定的均衡增长关系，因此长远来看，建筑业会随着整体经济增长而发展壮大。另外，我国建筑业增长相对于GDP有1－2年滞后期，GDP每增长1％，建筑业会在1－2年后增长1．5％－1．6％，所以根据目前国家宏观经济增长情况，可以预测未来短期内的建筑业大致增长状况，这对于建筑业和房地产投资有指导意义。     

干旱对豫西主要农作物生产的影响——以河南伊川县为例

以伊川县为例,分析各季节降水、气温变化趋势及干旱对主要作物生育和产量形成因素的影响.结果表明:伊川年降水量呈减少趋势,近10年春季、夏季降水量减少较多,气温升高加剧了干旱的发展;冬小麦干旱减产年表现为底墒差,播期前后干旱、春季干旱减产偏重,造成冬小麦基本苗和分蘖少、生育推迟,有效茎数、穗粒数偏少.初夏旱晚播、伏旱或初夏旱伏旱相连,使夏玉米发育迟缓,造成穗粒质量降低减产甚至植株干枯绝收.针对干旱对作物生产的影响,提出了适应对策.     

肺栓塞的诊治新进展

目的:了解肺栓塞是内源性或外源性栓子堵塞肺动脉或其分支引起肺循环障碍的临床和病理综合症.方法:收集近年有关肺栓塞的诊治新进展的研究资料并加以归纳综合.结果:其发病率随年龄增加而增加,成人发病率15%～64%,80岁以上高达70%.结论:因其诊断较困难,故肺栓塞的真正患病率仍不清楚,因此,应引起广大医务工作者的重视.     

The coming acceleration of global population ageing

The future paths of population ageing result from specific combinations of declining fertility and increasing life expectancies in different parts of the world. Here we measure the speed of population ageing by using conventional measures and new ones that take changes in longevity into account for the world as a whole and for 13 major regions. We report on future levels of indicators of ageing and the speed at which they change. We show how these depend on whether changes in life expectancy are taken into account. We also show that the speed of ageing is likely to increase over the coming decades and to decelerate in most regions by mid-century. All our measures indicate a continuous ageing of the world's population throughout the century. The median age of the world's population increases from 26.6 years in 2000 to 37.3 years in 2050 and then to 45.6 years in 2100, when it is not adjusted for longevity increase. When increases in life expectancy are taken into account, the adjusted median age rises from 26.6 in 2000 to 31.1 in 2050 and only to 32.9 in 2100, slightly less than what it was in the China region in 2005. There are large differences in the regional patterns of ageing. In North America, the median age adjusted for life expectancy change falls throughout almost the entire century, whereas the conventional median age increases significantly. Our assessment of trends in ageing is based on new probabilistic population forecasts. The probability that growth in the world's population will end during this century is 88%, somewhat higher than previously assessed. After mid-century, lower rates of population growth are likely to coincide with slower rates of ageing.     

Effects of household dynamics on resource consumption and biodiversity

Human population size and growth rate are often considered important drivers of biodiversity loss, whereas household dynamics are usually neglected. Aggregate demographic statistics may mask substantial changes in the size and number of households, and their effects on biodiversity. Household dynamics influence per capita consumption and thus biodiversity through, for example, consumption of wood for fuel, habitat alteration for home building and associated activities, and greenhouse gas emissions. Here we report that growth in household numbers globally, and particularly in countries with biodiversity hotspots (areas rich in endemic species and threatened by human activities), was more rapid than aggregate population growth between 1985 and 2000. Even when population size declined, the number of households increased substantially. Had the average household size (that is, the number of occupants) remained static, there would have been 155 million fewer households in hotspot countries in 2000. Reduction in average household size alone will add a projected 233 million additional households to hotspot countries during the period 2000-15. Rapid increase in household numbers, often manifested as urban sprawl, and resultant higher per capita resource consumption in smaller households pose serious challenges to biodiversity conservation.     

重庆市人口年龄结构与经济增长的关系研究

重庆市直辖以来,人口状况进入到了低出生率、低死亡率和低自然增长率阶段,利用抚养比作为测算人口年龄结构转变的指标,测算出了重庆市已经处于人口红利期;运用计量模型分析重庆市在人口红利阶段人口结构对投资及经济增长的影响,结论表明人口结构对投资存在影响,在人口转变过程中,重庆市应该抓住机遇最大限度地收获人口红利.