No discrimination against previous mates in a sexually cannibalistic spider

In several animal species, females discriminate against previous mates in subsequent mating decisions, increasing the potential for multiple paternity. In spiders, female choice may take the form of selective sexual cannibalism, which has been shown to bias paternity in favor of particular males. If cannibalistic attacks function to restrict a male's paternity, females may have little interest to remate with males having survived such an attack. We therefore studied the possibility of female discrimination against previous mates in sexually cannibalistic Argiope bruennichi, where females almost always attack their mate at the onset of copulation. We compared mating latency and copulation duration of males having experienced a previous copulation either with the same or with a different female, but found no evidence for discrimination against previous mates. However, males copulated significantly shorter when inserting into a used, compared to a previously unused, genital pore of the female.     

沿海和海洋生态系统与人类人口系统间的相互作用:关于消费如何调解这种相互作用的看法

人口、环境及可持续发展的困境 20世纪的80和90年代,环境工作者和普通公众普遍认为,不加控制的人口增长是造成各类环境退化的根本原因.这种新马尔萨斯人口论的观点最初出现在20世纪60年代Ehrlich所著的<人口炸弹>的文章中,该文以危言耸听的语气解释了那十年空前高的人口增长率[1～3].     

Evolutionary relationships of deep-sea hydrothermal vent and cold-water seep clams (Bivalvia: Vesicomyidae): results from the mitochondrial cytochrome oxidase subunit I

Phylogenetic relationships among vesicomyid clams (Bivalvia: Vesicomyidae) and their placement within the order Heterodonta were examined using mitochondrial encoded cytochrome oxidase subunit I (COI) DNA sequences. The presently analyzed vesicomyids represent a recent monophyletic radiation that probably occurred within the Cenozoic. Nucleotide phylogenetic analyses resolved discrete clades that were consistent with currently recognized species: Calyptogena magnifica, C. ponderosa, Ectenagena extenta, C. phaseoliformis, Vesicomya cordata, Calyptogena n. sp. (Gulf of Mexico), C. kaikoi, C. nautilei, C. solidissima and C. soyoae (Type-A). However, specimens variously identified as: V. gigas, C. kilmeri, C. pacifica, and V. lepta comprised two “species complexes”, each composed of multiple evolutionary lineages. Most taxa are limited to hydrothermal-vent or cold-seep habitats, but the “vent” versus “seep” clams do not constitute separate monophyletic groups. Current applications of the generic names Calyptogena, Ectenagena, and Vesicomya are not consistent with phylogenetic inferences. Received: 24 July 1997 / Accepted: 22 August 1997     

REACh im praxistest

In October 2003, the EU Commission presented the proposal for a new Chemicals Regulation. In late autumn 2005, Parliament and Council were working on finding their position on the Commission’s proposal. From November 2004 to April 2005, a simulation was carried out at EU level aiming to test the workability of registration under REACh. Based on a strategic partnership, the European Chemical Industry Council together with other industry associations, the EU Commission and a number of Member States had launched this project. 53 manufacturers or users of chemicals and competent authorities of 13 EU Member States took part in the simulation: eight registration cases were dealt with in parallel. The participants had to conduct the registration of a substance (including preparatory work) and the dossier evaluation by the authorities. The simulation was performed in a ’free-flow mode’, which means, that the participants worked without any guidance on how to practically implement the duties and tasks as laid down in the draft regulation. In the final phase of the project, the three strategic parners worked towards a common understanding on potential workability problems and suitable options for solutions. This process resulted in a report including a set of agreed recommendations on 12 identified workability issues The recommendations are mostly related to the co-operation between registrants, the sharing of responsibilities and communication between manufactures and down-stream users as well as technical and scientific aspects of dossier compilation., In addition, the recommendations address the need to develop a common understanding across Europe regarding the role of authorities in evaluating the registration dossiers and developing suitable tools for the evaluation. In addition to the set of practical recommendations, SPORT has demonstrated that useful insights in the workability of a new piece of legislation can be gained from simulating the key processes in practise already during the legislative process. Such pilot trials could be seen as a contribution toBetter Regulation, one of the strategic goals of the EU Commission.     

Evolution of habitat use by deep-sea mussels

Previous phylogenetic studies proposed that symbiont-bearing mussels of the subfamily Bathymodiolinae (Bivalvia: Mytilidae) invaded progressively deeper marine environments and evolved from lineages that decomposed wood and bone to specialized lineages that invaded cold-water hydrocarbon seeps and finally deep-sea hydrothermal vents. To assess the validity of the hypotheses, we examined two nuclear (18S and 28S rRNA) and two mitochondrial genes (COI and ND4) from a broad array of bathymodiolin species that included several recently discovered species from shallow hydrothermal seamounts. Bayesian phylogenetic analysis and maximum-likelihood estimates of ancestral character states revealed that vent species evolved multiple times, and that reversals in vent and seep habitat use occurred within the sampled taxa. Previous hypotheses regarding evolution from wood/bone-to-seeps/vents are supported in that mid-ocean hydrothermal vent species may represent a monophyletic group with one noticeable reversal. Earlier hypotheses about progressive evolution from shallow-to-deep habitats appear to hold with a few instances of habitat reversals.     

Characterization of Drought in the South Atlantic,United States

Drought has been less extensively characterized in the humid South Atlantic compared to the arid western United States. Our objective was to characterize drought in the South Atlantic and to understand whether drought has become more severe in this region over time. Here we used monthly streamflow to characterize hydrological drought. Hydrological drought occurred when streamflow fell below the 20th percentile over three consecutive months and terminated once streamflow remained above the 20th percentile for three consecutive months. We characterized the frequency, duration, magnitude, and severity of events using the above definition. Significant changes in drought characteristics were tested with Mann‐Kendall over three periods: 1930‐2010, 1930‐1969, and 1970‐2010. We show that 71% of drought events were shorter than six months, while 7% were multiyear events. There was little evidence of trends in drought characteristics to support the claim of drought becoming more severe in the South Atlantic over the 20th Century. The one exception was a significant increase in the joint probability of nearby basins being simultaneously in drought conditions in the southern portion of the study area from 1970 to 2010. While drought characteristics have changed little through time, decreasing average streamflow in non drought periods coupled with increasing water demand provide the context within which recent multiyear drought events have produced significant stress on existing water infrastructure.     

建造能源-效率的城市网络：欧洲和巴西的一些实践经验

今天的能源政策不得不把面向能源供应和能源需求两个主动性结合起来 .鉴于油价危机以来逐渐增加的环境限制的压力和节能行为，一个基于能源消耗管理和增加利用地方（可更新的）能源的新能源政策，已变得十分必要 .在这一研究里，地方和区域一级是合作伙伴 .能源效率项目的发展和市政府之间有关最佳实践信息的交换和传播，正在由节能机构的网络在世界范围组织起来 .下面就是这样的网络发展的几个实例 .……