Death from anthropogenic causes is partially compensatory in recovering wolf populations

There is substantial interest in how mortality rates affect animal populations, but mechanisms explaining when and under what circumstances particular causes of death incur demographic responses are far from clear. In theory, small or expanding populations should experience additive mortality from anthropogenic causes of death, but whether such effects are homogenous across a population or expressed only in certain high-risk individuals is open for debate. We used competing risks models to analyze mortality patterns among radio-collared wolves (Canis lupus, n = 711) from three populations in northwestern United States (1982-2004), and evaluated the degree to which anthropogenic mortality was additive vs. compensatory to natural demographic processes. Almost 80% (n = 320) of wolves dying of known fates were killed by anthropogenic causes (legal control, illegal killing, harvest in Canada, vehicle collision), and additive effects of anthropogenic mortality were most pronounced in northwestern Montana where wolf exposure to humans and livestock was high compared to either the Greater Yellowstone Area or central Idaho, where anthropogenic risk was lower. In contrast, risk from natural hazards was lower in northwestern Montana than in the other areas, implying some degree of compensatory mortality from anthropogenic risk. Animals recruited to the study following human-wolf conflict had markedly higher anthropogenic risk than those recruited for standard monitoring purposes, and juvenile wolves as well as dispersers, succumbed to higher anthropogenic risk. Multivariate models revealed that increasing wolf population density promoted higher anthropogenic risk and reduced natural risk, indicating that partially-compensatory effects of anthropogenic mortality actually became increasingly additive with population density. The observed compensatory mortality and hazard heterogeneity in our study implies that demographic responses to mortality risk may be complex and more subtle than previously thought; the density-dependent effect of anthropogenic mortality portends a stabilizing influence of humans on recovering wolf populations. We conclude that future assessment of the role of anthropogenic mortality should include individual-based hazard estimation as a complement to traditional population-level approaches.     

气象条件对柑桔果实生长的影响

本文研究了红桔、锦橙和普通甜橙果实各生长阶段果径增长规律，建立了果实生长与气象因子的关系方程，揭示了柑桔果实生长规律及影响柑桔果实生长的气候问题。     

The Need and Efforts to Industrialized Housing from Developers

There exists the problems of low technology, low quality of components and lacked process in the traditional houses. This article states the experience and lesson in the development of Chongqing Longhu Garden, and the efforts of developers in the industrialized housing.     

湖北宣恩烟区气候因素和烤烟质量特点分析

笔者分析了湖北宣恩烟叶产区适宜种植烤烟的基本条件、气候因素和所产烟叶的质量特点，并与国外优质烟叶产区津巴布韦烤烟进行了比较，结果表明：该烟区具有无霜期长、大于10℃积温高、日均气温大于20℃的时间长等突出特点，达到了烤烟最适宜类型生长发育所要求的气候条件；宣恩烤烟颜色橘黄或柠檬黄，成熟度好，与津巴布韦烟叶外观质量相当；宣恩烟叶填充力较高，各化学成分含量较适宜，组成比例协调；感官评吸质量较好     

几种利用方式下酸性硫酸盐土的环境风险及其连锁效应

研究并比较了不同利用方式下酸性硫酸盐土酸形态和铝形态的结构特征,分析了硫形态与酸形态、酸形态与铝形态之间的相关性。研究发现,酸性硫酸盐土的不同利用类型中,土壤酸度由大到小依次为:鱼塘塘基、荒稻田>稻田>荒旱地>改良稻田>蔗田>红树林迹地;活性铝含量由高到低依次为:荒旱地>鱼塘塘基、荒稻田>稻田>改良稻田>蔗田>红树林迹地。土壤酸度和铝形态含量的层间差异较为显著,多数随深度增加呈逐渐上升的趋势。酸性硫酸盐土中的硫形态—酸—铝形态之间有明显的连锁关系。     

气象服务新农村建设工作的调研与思考

通过对气象为新农村建设服务基本情况的调研,较系统地分析了气象信息传递、农村生活条件、农村对气象服务的需求,剖析了气象为新农村建设服务的制约因素,最后提出了对策.     

张家界市永定区气象灾害防御及为农服务的现状与对策建议

我国气象灾害及其衍生灾害发生频繁，对经济社会发展和人民群众生产生活产生严重影响。农村是气象工作最广阔的领域，气象灾害防御工作对农业农村发展影响深远。本文以张家界市永定区为例，重点描述了本地区主要的气象灾害类型，分析当阶段农村气象灾害的防御现状，并从政府、资金、队伍、科技、防御、科普等六个方面，提出了气象灾害防御能力建设及为农服务的具体措施与建议。     

VaR度量金融风险的几个问题

针对VaR模型中的delta-正态模型的计算,分析了其中存在的几个问题并进行了改进。结果认为,用区间估计替代点估计可以提高VaR值的有效性;在用CAPM模型计算股票资产的可能损失时,不能丢失常数项,否则计算值偏大。另鉴于传统VaR模型不能评估市场因子变化时资产损失发生的概率,现基于高维正态分布的计算方法提出了用VaR度量金融市场风险的新方法。     

气象因素对淮北地区夏玉米生产的影响和对策

分析了 1996～ 1998年降水和日照对宿县、涡阳二点玉米试验的影响 ,认为 7～ 8月份 ,尤其是 8月份降水日照是影响淮北地区夏玉米生产的重要因素 ,并对稳定提高夏玉米单产提出了相应的对策