Environment-specific elasticity and sensitivity analysis of the stochastic growth rate

For matrix population models, analyses of how sensitive the population growth rate is to changes in vital rates (i.e. perturbations) are important for studies of life history evolution as well as for management and conservation of threatened species. There are two types of sensitivity analyses corresponding to absolute (sensitivity) or relative (elasticity) changes in the vital rates and both types can be applied to both deterministic and stochastic matrix population models. To date, most empirical studies of elasticity and sensitivity of the stochastic growth rate have examined the response to perturbations in the vital rates in a complete set of possible environments. However, it is often of interest to examine the response to perturbations occurring in only a subset of the possible environments. This has been done for periodic time-varying models elsewhere, but here we describe a recently published method for calculating the environment-specific sensitivity and elasticity of the stochastic growth rate and apply this method to data. These environment-specific perturbation analyses provide a logical way of dividing the sensitivity and elasticity among the environments. They give important insight into the selection regime in different environments and can provide valuable information for making management decisions and management evaluations in stochastic environments.     

Transmission of employment shocks before and after the Oklahoma City tornado

This study examined the economic impact of the May 3, 1999 Oklahoma tornado outbreak on the labor markets of Oklahoma City (OK), Wichita (KS), and Kansas City (MO). In particular, this article examines the transmission of shocks to employment growth across these different labor markets. Using monthly employment data from January 1990 to December 2004, we provide empirical evidence on the cross-market relationships that existed before and after the Oklahoma City tornado. The results suggest that the impact of the wind event may have altered labor market dynamics in Oklahoma City, as well as Wichita and Kansas City.     

产业间设备投资关联性分析

通过理论与实证分析，本文说明了产业间设备投资关联性对ＧＮＰ的促进作用，可作为制定宏观经济政策的参考。     

Effects of Harvest of Nontimber Forest Products and Ecological Differences between Sites on the Demography of African Mahogany

Abstract: The demographic impacts of harvesting nontimber forest products (NTFP) have been increasingly studied because of reports of potentially unsustainable harvest. Nevertheless, our understanding of how plant demographic response to harvest is altered by variation in ecological conditions, which is critical for developing realistic sustainable‐use plans, is limited. We built matrix population models to test whether and how variation in ecological conditions affects population responses to harvest. In particular, we examined the effect of bark and foliage harvest on the demography of populations of African mahogany (Khaya senegalensis) in two contrasting ecological regions of Benin, West Africa. K. senegalensis bark and foliage harvest significantly reduced its stochastic population growth rates, but ecological differences between regions had a greater effect on population growth rates than did harvest. The effect of harvest on population growth rates (Δλ) was slightly stronger in the moist than in the drier region. Life‐table response experiments revealed that the mechanism by which harvesting reduced λ differed between ecological regions. Lowered stasis (persistence) of larger life stages lead to a reduction in λ in the drier region, whereas lowered growth of all life stages lowered λ in moist region. Potential strategies to increase population growth rates should include decreasing the proportion of individuals harvested, promoting harvester‐owned plantations of African mahogany, and increasing survival and growth by promoting no‐fire zones in gallery forests. Our results show how population responses to harvest of NTFP may be altered by ecological differences across sites and emphasize the importance of monitoring populations over the climatic range in which they occur to develop more realistic recommendations for conservation.     

改革开放30年人的发展:评价与反思

传统的“唯GDP ”的经济发展方式成为中国未来经济可持续发展的桎梏,转变发展方式,提高经济增长质量,倡导共享式、包容性增长成为中国经济发展的新主题,而这种发展模式的基本导向就是促进“人的发展”.基于这样一个视角,本文依据经济增长质量提高的要求,从人的素质、人的福利、人的保障、人的迁移4个方面构建综合评价指标体系,对改革开放30年人的发展程度进行了测度与评价.评价结果显示:随着经济不断发展,30年间中国人的发展状况得到明显提高,但是人的发展指数以及人的素质指数、人的福利指数、人的保障指数、人的迁移指数、经济状况指数、资源环境指数仍需不断改善.未来中国在提高增长质量的过程中要促进人的发展,强调经济发展与人的发展的协调,树立“以人为本”的发展理念,着眼于人性,重视人的存在、人的价值、人的意义,建立促进人的素质和能力提升的机制和体制,确定以“富民”为目标的经济发展道路,实现人的发展与生态环境协调发展的有机统一.     

硝酸镧对铜绿微囊藻生长特性的影响

在实验室内利用BG₁₁培养液培养,研究了不同硝酸镧[La(NO₃)₃]浓度下铜绿微囊藻(Microcystis aeruginosa)FACHB526的生长特性,并在实验后期测定了藻细胞中的藻毒素含量.以藻细胞数和叶绿素a含量所表示的最大比生长率和最大现存量为指标,在一定浓度范围内,La(NO₃)₃可明显刺激铜绿微囊藻FACHB526的生长.但当培养液中La(NO₃)₃浓度很高时(125000g/L),却对铜绿微囊藻FACHB526的生长表现出明显的抑制作用.稀土盐类La(NO₃)₃对藻生长的低浓度刺激和高浓度抑制效应对全面了解水华爆发机制有一定的意义.从FACHB526藻中可分离检测出4种藻毒素变型MC-LR,MC-RR,MC-LW,MC-LF.     

环保投资对国民经济的作用机理与贡献度模型研究

在界定环保投资概念及范围的基础上,根据环保投资作用于经济的原理,借鉴环境经济投入产出的基本思想,构建了环保投资对经济贡献的投入产出模型,主要包括污染治理设施投资对经济的影响模型和污染治理设施运行成本对经济的影响模型,并对该模型进行了实证模拟分析.      

试用可持续发展眼光审视中国持续高涨的水坝建设

水坝建设往往忽略了生态影响,轻视了社会问题,高估了经济效益.介绍了国际上对水坝问题认识的最新进展和主要观点,分析了我国水坝建设的现状和问题--西部建坝热潮不退的原因.从现状来看,中国的已建水坝已使长江流域生态退化,加剧了黄河的断流,加重了淮河水质的恶化等.最后以科学发展观为指导,对中国的水坝建设作了一些深层的思考.      

广东省环境库兹涅茨特征分析

介绍了环境库兹涅茨假说经验结论,对其所涉及的环境质量随着经济增长出现"先恶化,后改善"的现象进行了分析,指出环境质量的变化不会自动产生,必须在环境政策的干预下才能实现.结合广东省废水、废气以及COD_Cr和SO₂等污染物排放量及经济增长数据,构建了广东省环境库兹涅茨曲线,实证分析了广东省经济增长与环境质量之间的关系;经过"十五"以来的环境综合整治,广东省废水和废气排放总量正在并将逐渐继续下降,部分环境指标正在接近转折点.      

芦苇和香蒲种间竞争对混合种植人工湿地污染河水净化特性的影响

为了系统评估混合种植人工湿地中植物组成的变化规律,以及物种竞争对湿地植物-微生物相互作用和湿地净化功能的影响特性,基于芦苇、香蒲混合种植的表面流人工湿地中试实验,开展了连续5年的研究.结果表明,在混合种植人工湿地中,芦苇从进水端开始侵蚀香蒲生态位,芦苇的生长密度和生物量在5年后分别达到了香蒲的11.5和6.1倍,但香蒲...