Effects of Climate Change,Invasive Species,and Disease on the Distribution of Native European Crayfishes

Climate change will require species to adapt to new conditions or follow preferred climates to higher latitudes or elevations, but many dispersal‐limited freshwater species may be unable to move due to barriers imposed by watershed boundaries. In addition, invasive nonnative species may expand into new regions under future climate conditions and contribute to the decline of native species. We evaluated future distributions for the threatened European crayfish fauna in response to climate change, watershed boundaries, and the spread of invasive crayfishes, which transmit the crayfish plague, a lethal disease for native European crayfishes. We used climate projections from general circulation models and statistical models based on Mahalanobis distance to predict climate‐suitable regions for native and invasive crayfishes in the middle and at the end of the 21st century. We identified these suitable regions as accessible or inaccessible on the basis of major watershed boundaries and present occurrences and evaluated potential future overlap with 3 invasive North American crayfishes. Climate‐suitable areas decreased for native crayfishes by 19% to 72%, and the majority of future suitable areas for most of these species were inaccessible relative to native and current distributions. Overlap with invasive crayfish plague‐transmitting species was predicted to increase. Some native crayfish species (e.g., noble crayfish [Astacus astacus]) had no future refugia that were unsuitable for the modeled nonnative species. Our results emphasize the importance of preventing additional introductions and spread of invasive crayfishes in Europe to minimize interactions between the multiple stressors of climate change and invasive species, while suggesting candidate regions for the debatable management option of assisted colonization. Efectos del Cambio Climático, Especies Invasoras y Enfermedades sobre la Distribución de Cangrejos de Río Europeos Nativos     

Dynamics of Hybridization and Introgression in Red Wolves and Coyotes

Abstract:  Hybridization and introgression are significant causes of endangerment in many taxa and are considered the greatest biological threats to the reintroduced population of red wolves ( Canis rufus ) in North Carolina (U.S.A.). Little is known, however, about these processes in red wolves and coyotes ( C. latrans ). We used individual-based simulations to examine the process of hybridization and introgression between these species. Under the range of circumstances we considered, red wolves in colonizing and established populations were quickly extirpated, persisted near the carrying capacity, or had intermediate outcomes. Sensitivity analyses suggested that the probabilities of quasi extinction and persistence of red wolves near the carrying capacity were most affected by the strength of two reproductive barriers: red wolf challenges and assortative mating between red wolves and coyotes. Because model parameters for these barriers may be difficult to estimate, we also sought to identify other predictors of red wolf population fate. The proportion of pure red wolves in the population was a strong predictor of the future probabilities of red wolf quasi extinction and persistence. Finally, we examined whether sterilization can be effective in minimizing introgression while allowing the reintroduced red wolf population to grow. Our results suggest sterilization can be an effective short-term strategy to reduce the likelihood of extirpation in colonizing populations of red wolves. Whether red wolf numbers are increased by sterilization depends on the level of sterilization effort and the acting reproductive barriers. Our results provide an outline of the conditions likely required for successful reestablishment and long-term maintenance of populations of wild red wolves in the presence of coyotes. Our modeling approach may prove generally useful in providing insight into situations involving complex species interactions when data are few.     

有障碍物开敞空间可燃气云爆炸超压场的数值模拟

利用计算流体动力学软件AutoReaGas定量研究障碍物、障碍物阻塞比对开敞空间可燃气云爆炸超压场的影响以及爆燃超压随测点距离变化的分布规律。研究结果表明:当有障碍物存在时,爆炸峰值超压会显著增加,且峰值超压随着障碍物阻塞比的增加而增加。对于有障碍物条件下开敞空间的丙烷气云爆炸,无论是气云内部还是气云外部,随着距爆心距离的增加,峰值超压都有减小的趋势。     

A framework for human error risk analysis of coal mine emergency evacuation in China

Evacuation from underground coal mine in emergency as soon as possible makes the difference between life and death. Human factors have an important impact on a successful evacuation, but literature review shows that there is a lack of consideration of human error risk during coal mine emergency evacuation in China. To address the above problems, in this paper, we established a framework for human error risk analysis of coal mine emergency evacuation, consisting of scenario and task analysis, risk assessment and risk reduction. A general evacuation procedure which is applicable for different causes is detailed through the scenario and task analysis. A new method based on expert judgment, named OGI-Model, is proposed to evaluate the reliability of human safety barrier. In this new approach, human safety barrier is divided into three sub-barriers, i.e., organization safety sub-barrier (OSSB), group safety sub-barrier (GSSB), and individual safety sub-barrier (ISSB). Each sub-barrier consists of a series of concrete measures against specific evacuation actions. An example is provided in this paper to demonstrate the use of this framework and its effectiveness.     

"绿色壁垒"的思考与应对

"绿色壁垒"是<WTO贸易与技术壁垒协议>的重要组成部分.随着中国加入wTO,世界经济的一体化,传统的非关税壁垒被逐步削减,绿色壁垒以鲜明的时代特征正日益成为国际贸易发展的主要关卡,因此研究wTO贸易技术壁垒协议中的"绿色壁垒",对于我国入世后的国际贸易、企业生产和民众绿色消费都具有十分重要的意义.     

入世后,绿色壁垒与我国环境保护事业

绿色壁垒已经成为影响贸易活动和促进环境保护的一种有效工具，给中国环境保护事业带来了前所未有的机遇和挑战。面对绿色壁垒提出了我国环保部门应完善环保法律法规、提高环境标准、促进清洁生产、积极开展ISO14000认证和提高绿色意识等对策措施。     

Analysis of Flax and Cotton Fiber Fabric Blends and Recycled Polyethylene Composites

Manufacturing composites with polymers and natural fibers has traditionally been performed using chopped fibers or a non-woven mat for reinforcement. Fibers from flax (Linum usitatissimum L.) are stiff and strong and can be processed into a yarn and then manufactured into a fabric for composite formation. Fabric directly impacts the composite because it contains various fiber types via fiber or yarn blending, fiber length is often longer due to requirements in yarn formation, and it controls the fiber alignment via weaving. Composites created with cotton and flax-containing commercial fabrics and recycled high-density polyethylene (HDPE) were evaluated for physical and mechanical properties. Flax fiber/recycled HDPE composites were easily prepared through compression molding using a textile preform. This method takes advantage of maintaining cotton and flax fiber lengths that are formed into a yarn (a continuous package of short fibers) and oriented in a bidirectional woven fabric. Fabrics were treated with maleic anhydride, silane, enzyme, or adding maleic anhydride grafted polyethylene (MAA-PE; MDEX 102-1, Exxelor^® VA 1840) to promote interactions between polymer and fibers. Straight and strong flax fibers present problems because they are not bound as tightly within yarns producing weaker and less elastic yarns that contain larger diameter variations. As the blend percentage and mass of flax fibers increases the fabric strength, and elongation generally decrease in value. Compared to recycled HDPE, mechanical properties of composite materials (containing biodegradable and renewable resources) demonstrated significant increases in tensile strength (1.4–3.2 times stronger) and modulus of elasticity (1.4–2.3 times larger). Additional research is needed to improve composite binding characteristics by allowing the stronger flax fibers in fabric to carry the composites load.     

水力帷幕防治海水入侵的数值模拟研究

为比较应用于防治海水入侵工程的水力帷幕效果,利用垂向二维非均质流体的对流-弥散模型,运用伽辽金有限元法求解,并用物理实验结果验证其有效性.将模型应用于模拟广西北海市海城区海水入侵过程及水力帷幕防治海水入侵效果,分别计算了超采地下水、抽水、注水和抽-注水情况下咸淡水界面随时间推移过程,并分析咸淡水界面推移与抽、注水流量及抽、注水孔位置之间关系,通过比较得出注水是北海市防治海水入侵较为理想的措施.     

逆流式冷却塔淋水噪声特性分析与声屏障设计

针对某住宅的冷却塔噪声治理工程中的具体情况,采用声屏障对其进行噪声治理,阐述了噪声特性、控制措施及治理效果,对材料的选择和布置以及声屏障的结构设计问题进行了细致的分析,在工程实际应用中取得了很好的降噪效果。     

国际贸易中环境贸易壁垒问题及其对策探析

介绍了国际贸易中存在的环保问题以及环境贸易壁垒的概念、特点及内容、形式,概述了环境贸易壁垒对国际贸易的影响,尤其是对我国外贸的影响,举例说明了我国创外汇较高的几个行业在国际贸易中因受环境贸易壁垒的制约所面临的严峻考验,并与可持续发展的观点相结合提出了针对环境贸易壁垒问题的对策与建议。