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1.
Long-term stationary studies on the ecology of the northern mole vole (Ellobius talpinus Pall.), performed by the mark–recapture method from 1985 to 1997, have provided original data on population dynamics and structure. The analysis shows that, to reveal cyclic fluctuations of population size in this species, the period of three years should be taken as a unit of time for estimating the duration of one phase. The 12-year population cycle in E. talpinus has four distinct phases: an increase, a peak, a decline, and a minimum. At each phase, the population is characterized by certain features of family structure, age composition, birth and death rates, and the composition of migrants.  相似文献   
2.
通过收集北京市2010~2016年逐日呼吸和心脑血管疾病死亡数据、污染物(BC、PM2.5、SO2、O3和NO2)日均浓度资料以及同期的气象资料,采用广义相加模型(GAMs)中的主效应模型、非参数二元响应模型和温度分层模型探讨了北京市气温、PM2.5和BC单效应,以及气温与PM2.5和BC交互作用分别对呼吸和心脑血管疾病死亡人数的影响.单效应分析结果表明,气温与两种疾病死亡人数的累计暴露-反应关系均呈“J”型分布特征,最适温度为24℃;累计滞后一天情况下PM2.5和BC的健康效应均最显著,此时PM2.5和BC浓度每升高四分位间距(IQR),呼吸系统疾病死亡人数超额增加百分比(ER)分别为2.21%和1.80%,心脑血管疾病死亡人数ER分别为2.02%和1.48%.交互作用的研究结果表明,高温与高浓度的PM2.5(或BC)对疾病死亡的影响存在协同效应,且高温条件下BC对疾病死亡影响的健康风险大于PM2.5,当气温大于24℃时,BC和PM2.5浓度每升高IQR对应的呼吸系统疾病死亡人数ER分别为6.22%和6.17%,心脑血管疾病死亡人数ER分别为5.01%和3.97%.虽然BC只占PM2.5的一部分,但BC对人群健康的影响不容忽视,应该引起足够的重视.  相似文献   
3.
为探讨中国臭氧短期暴露与死亡率之间的关系,更新适用于中国本地化的暴露-反应系数,本研究全面检索了1990年1月1日-2020年1月1日在Web of Science数据库、PubMed、中国期刊全文数据库(CNKI)、万方医学数据库和维普数据库上发表的文献,以"O3/臭氧(ozone)"、"空气污染(air pollution)"、"死亡率(mortality)"、"时间序列(time-series)","病例交叉(case-crossover)"、"中国(China)"为关键词,对符合纳入标准的文献进行质量评价后提取相关数据,通过Meta分析方法合并估计值.结果显示,大气中臭氧浓度每增加10 μg·m-3,人群总死亡率、心血管系统疾病和呼吸系统疾病死亡率分别增加0.40%(95% CI:0.28%~0.52%)、0.67%(95% CI:0.46%~0.88%)、0.23%(95% CI:-0.20%~0.66%).亚组分析结果表明,除季节外,温度、年龄、性别均不存在显著的修饰作用.本文结论可为开展城市大气污染健康风险精细化评估提供依据.  相似文献   
4.
谢元博  李巍 《环境科学学报》2013,33(6):1763-1770
保护居民健康是北京市能源系统优化管理和大气污染治理的重要目标.本研究基于北京市的社会经济发展目标并结合相关节能减排和环保要求,针对全市2010-2020年间的能源消费分别设计了高、中、低3种约束情景,通过LEAP模型预测了全市至2020年的能源消费量与S02、NOx、PM10和PM2.5等4种主要大气污染物的排放强度,并采用泊松回归模型对3种情景下主城区居民受环境空气中这4种大气污染物的暴露危害所导致的健康风险进行了评估.结果显示:相对低约束情景,高约束情景至2020年可避免与S02、NOx、PM10和PM2.5污染相关的死亡危害分别为2663、6359、4720和4104人·a-1,而且在高约束情景下煤炭消费比重每下降1%,可相应地避免约1400人·a-1的污染急性死亡.由此建议北京市实施更加严格的节能和减排措施,严控煤炭消费总量,进一步优化能源结构,最大程度地降低能源消费导致的大气污染所产生的居民健康风险.  相似文献   
5.
建立了一种基于指示性污染物的非突发性环境健康风险评价模式。根据研究区域的能源类型及气候条件选择对该区域人群健康产生明显影响的指示性污染物,并根据多个城市及地区的历史数据确定指示性污染物与常住人口死亡率之间的定量对应关系,将大气预测模型和GIS系统进行集成开发,再将指示性污染物浓度与区域常住人口死亡率之间的定量对应关系嵌入与GIS集成后的大气预测模型中..通过将区域气象数据及规划中关于指示性污染物连续排放的源强数据输入上述模型进行模拟预测,得出区域不同级别大气环境健康风险范围分布。  相似文献   
6.
Abstract: Juvenile growth rate and adult body size are important components of life‐history strategies because of their direct impact on fitness. The diamondback terrapin (Malaclemys terrapin) is a sexually dimorphic, long‐lived turtle inhabiting brackish waters throughout the Atlantic and Gulf coasts of the United States. In parts of its range, terrapins face anthropogenically imposed mortality: juveniles of both sexes inadvertently enter commercial crab traps and drown. For adult females, the carapace eventually grows large enough that they cannot enter traps, whereas males almost never reach that critical size. We compared age structure, carapace dimensions, growth curves, and indices of sexual dimorphism for a Chesapeake Bay population of terrapins (where mortality of turtles is high due to crab traps) with contemporary terrapins from Long Island Sound and museum specimens from Chesapeake Bay (neither group subject to commercial crab traps). We also calculated the allochronic and synchronic rates of evolutionary change (haldanes) for males and females to measure the rate of trait change in a population or between populations, respectively. We found a dramatic shift to a younger male age structure, a decrease in the length of time to terminal female carapace size, a 15% increase in female carapace width, and an increase in sexual dimorphism in Chesapeake Bay. In a new twist, our results implicate a fishery in the selective increase in size of a reptilian bycatch species. These sex‐specific changes in life history and demography have implications for population viability that need to be considered when addressing conservation of this threatened turtle.  相似文献   
7.
Abstract: One potential contributor to the worldwide decline of bird populations is the increasing prevalence of roads, which have several negative effects on birds and other vertebrates. We synthesized the results of studies and reviews that explore the effects of roads on birds with an emphasis on paved roads. The well‐known direct effects of roads on birds include habitat loss and fragmentation, vehicle‐caused mortality, pollution, and poisoning. Nevertheless, indirect effects may exert a greater influence on bird populations. These effects include noise, artificial light, barriers to movement, and edges associated with roads. Moreover, indirect and direct effects may act synergistically to cause decreases in population density and species richness. Of the many effects of roads, it appears that road mortality and traffic noise may have the most substantial effects on birds relative to other effects and taxonomic groups. Potential measures for mitigating the detrimental effects of roads include noise‐reduction strategies and changes to roadway lighting and vegetation and traffic flow. Road networks and traffic volumes are projected to increase in many countries around the world. Increasing habitat loss and fragmentation and predicted species distribution shifts due to climate change are likely to compound the overall effects of roads on birds.  相似文献   
8.
A reproductive-health knowledge, attitudes and practices (KAP) survey was carried out among 468 Afghan women of reproductive age. A convenience sample of women was selected from attendees in the outpatient departments of four health facilities in Kabul. Seventy-nine per cent of respondents had attended at least one antenatal consultation during their last pregnancy. Two-thirds (67 per cent) delivered their first child between 13 and 19 years. The Caesarean-section rate was low (1.6 per cent). Two-thirds (67 per cent) of deliveries occurred in the home. The contraceptive prevalence rate was 23 per cent (16 per cent modern and 7 per cent natural methods). Twenty-four per cent had knowledge of any STIs, although most of these women did not know correctly how to prevent them. Most of the women (93 per cent) needed authorization from their husband or a male relative before seeking professional health-care. In multivariate analysis, women's schooling was significantly associated with antenatal-care attendance (AOR 4.78), institutional delivery (AOR 2.29), skilled attendance at birth (AOR 2.07) and use of family planning (AOR 4.59). Reproductive-health indicators were noted to be poor even among these women living in Kabul, a group often considered to be the most privileged. To meet the reproductive-health needs of Afghan women, the socio-cultural aspects of their situation--especially their decision-making abilities -- will need to be addressed. A long-standing commitment from agencies and donors is required, in which the education of women should be placed as a cornerstone of the reconstruction process of Afghanistan.  相似文献   
9.
Abstract

Bangladesh is on target for achieving the Millennium Development Goal 4 relating to infant and under-five mortality because of very rapid reduction in mortality in recent years. But this rate of reduction may be difficult to sustain and may hamper the achievement of Millennium Development Goal 4. Therefore, the main objective of this paper is to discuss and compare the different covariates of infant and under-five mortality in the context of overall country, urban and rural levels of Bangladesh using discriminant analysis. For this, the data are taken from Bangladesh Demographic and Health Survey, 2004. In discriminant analysis, the stepwise procedure has been picked up and only the significant variables are ranked according to the rank of Wilk’s Lambda values. The canonical discriminant function coefficients (unstandardized and standardized) for the predictor variables have also been calculated. Both the results show that breastfeeding is the most important variable in discriminating the two groups of mothers, i.e., mothers experiencing to infant mortality or not and mothers experiencing to under-five mortality or not. The related results of discriminant function also indicate that the discriminant function is statistically significant and discriminates well. Therefore, improvements in the health system are essential for promoting the breastfeeding practices (both inclusive and exclusive), which may be the effective strategies to reach families and communities with targeted messages and information.  相似文献   
10.
Abstract: Theory suggests that demographic and genetic traits deteriorate (i.e., fitness and genetic diversity decrease) when populations become small, and that such deterioration could precipitate positive feedback loops called extinction vortices. We examined whether demographic attributes and genetic traits have changed over time in one of the 2 remaining small populations of the highly endangered Iberian lynx (Lynx pardinus) in Doñana, Spain. From 1983 to 2008, we recorded nontraumatic mortality rates, litter size, offspring survival, age at territory acquisition, and sex ratio. We combined these demographic attributes with measures of inbreeding and genetic diversity at neutral loci (microsatellites) and genes subjected to selection (major histocompatibility complex). Data on demographic traits were obtained through capture and radio tracking, checking dens during breeding, track surveys, and camera trapping. For genetic analyses, we obtained blood or tissue samples from captured or necropsied individuals or from museum specimens. Over time a female‐biased sex ratio developed, age of territory acquisition decreased, mean litter size decreased, and rates of nontraumatic mortality increased, but there were no significant changes in overall mortality rates, standardized individual heterozygosity declined steadily, and allelic diversity of exon 2 of class II major histocompatibility complex DRB genes remained constant (2 allelic variants present in all individuals analyzed). Changes in sex ratio and age of territory acquisition may have resulted from demographic stochasticity, whereas changes in litter size and nontraumatic mortality may be related to observed increases in inbreeding. Concomitant deterioration of both demographic attributes and genetic traits is consistent with an extinction vortex. The co‐occurrence, with or without interaction, of demographic and genetic deterioration may explain the lack of success of conservation efforts with the Doñana population of Iberian lynx.  相似文献   
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