Two populations of open clusters

The paper proposes a division of the local open clusters into two different disklike subpopulations on the base of the metallicity enhancement history, spatial distribution in the Galaxy and morphology of their C-M diagrams. The thin disk population objects exhibit higher metallicities and are more closely concentrated to the center and the disk of the Galaxy than the thick disk clusters. The former contain also frequently blue stragglers while the later exhibit the presence of Clump giant members, typical for the thick disk globular clusters. Kinematical properties of the two considered open cluster subpopulations remain unknown due to the lack of observational data.     

Water-level fluctuations, emersion regimes, and variations of echinoid populations on a Caribbean reef flat

This paper examines fluctuations in water level over a Caribbean reef flat at Punta Galeta, Panamá. In an analysis of approximately ten years of records, the mean diurnal range of the tides was 24·5 cm and varied <2 cm from year to year. Daily mean water levels varied erratically over a range of approximately 30 cm. Monthly mean water levels fluctuated seasonally over a range of about 10 cm and were consistently higher than those at the regional tidal reference station at Cristóbal. On days with more wave action, water levels at Galeta increased relative to those at Cristóbal, suggesting that waves were ‘pumping’ water onto the reef flat. The monthly mean water levels at the two sites were not correlated, indicating that tidal data from conventional stations in deeper water cannot be extrapolated to reef flats, except as estimates of minimum potential water levels.Most of the reef flat was within 6 cm vertical span just below mean lower low water. The highest elevations within this range were exposed above water level for an average of 918 hours per year, as compared with 144 hours per year at the lowest elevation. Most exposures lasted less than 10 hours, with a modal duration of 3–5 hours; however, exposures longer than 12 hours occurred at nearly all elevations in all years. Exposures of the reef flat were most frequent between February and June and between August and November, a pattern apparently caused by a combination of seasonal oscillations of regional sea levels, the annual pattern of the solstitial tides, and waves generated by seasonal trade winds.The fluctuations in water levels apparently affected the abundances of some species of sea urchins on the reef flat. Populations of Lytechinus variegatus and Diadema antillarum declined or disappeared from the reef flat during seasons of repeated subaerial exposures, but recolonized the habitat in periods of higher water levels. Although they are reported to suffer heavy mortality during emersion, Echinometra lucunter and E. viridis did not exhibit reductions in abundance that were synchronous with the seasonal exposures of the reef flat.     

山东沿海菲律宾蛤仔不同地理群体遗传多样性的AFLP分析

利用AFLP技术对山东沿海菲律宾蛤仔（Ruditapes philippinarum）4个野生群体（乳山、无棣、牟平、即墨）进行了遗传多样性分析。采用6对引物组合对4个群体进行扩增,共得到356个位点,乳山群体、无棣群体、牟平群体和即墨群体的多态位点比例依次为74.40%、70.50%、72.80%、74.70%,具有较高的遗传多样性水平。其中,即墨群体多态性比例最高,无棣群体多态性比例最低。聚类分析表明,各群体间的遗传距离在0.0263～0.0448之间,乳山群体和无棣群体间的遗传距离最近(0.0263),两群体首先聚在一起,随后与牟平群体和即墨群体聚在一起。     

生物成因煤层气实验研究现状与进展

总结了当前国内外关于生物成因煤层气生成机理及其影响因素、煤层中厌氧菌及其与煤层生物甲烷生成的关系和生物成因煤层气生成模拟实验研究方面的最新进展。细菌计数和分子生态学研究是考察煤层厌氧菌数量和生理特征的主要方法。煤抽提物的有机地球化学分析验证了煤层可作为生气基质产气,而生物模拟实验研究了煤层生物甲烷生成过程中各种影响因素的影响特征。国内对煤层厌氧菌的研究主要集中在细菌计数和富集培养上,而国外研究则更多关注煤中本源产甲烷菌的分子生态学特征和菌种的改良研究。     

How to allocate limited healthcare resources: Lessons from the introduction of antiretroviral therapy in rural Mozambique

Proper allocation of limited healthcare resources is a challenging task for policymakers in developing countries. Allocation of and access to these resources typically varies based on how need is defined, thus determining how individuals access and acquire healthcare. Using the introduction of antiretroviral therapy in southern Mozambique as an example, we examine alternative definitions of need for rural populations and how they might impact the allocation of this vital health service. Our results show that how need is defined matters when allocating limited healthcare resources and the use of need-based metrics can help ensure more optimal distribution of services.     

基于概率加权估计的中国极端气温时空分布模拟试验

建立可监测、可预报的雨涝危险性指数与暴雨洪涝受灾人口的关系模型,对暴雨洪涝灾前、灾中、灾后人口受灾情况快速评估具有重要意义。以湖北省为例,利用小时降水、日最大降水量、累积降水量与暴雨持续天数等气象资料以及水系、高程等孕灾环境资料,构建了雨涝危险性指数。结合历史洪涝受灾人口资料,建立基于雨涝危险性指数的暴雨洪涝受灾人口灾损曲线。按照重现期划分雨涝危险性等级,并通过计算不同重现期雨涝危险性指数的致灾阈值,建立危险性等级与受灾人口的定量关系模型。结果显示：（1）湖北省暴雨高危险区主要位于江汉平原以东,其次是鄂西南南部、江汉平原南部。（2）通过历史暴雨过程受灾情况比较,包含小时雨量和孕灾环境的雨涝危险性指数更能呈现暴雨过程的受灾程度。（3）湖北省暴雨洪涝受灾人口与雨涝危险性指数呈幂函数关系,年及暴雨过程实际受灾人口与拟合受灾人口的相关系数分别达0.800和0.891。（4）利用5 a、10 a和20 a三个重现期将雨涝危险性指数划分为三个等级,当雨涝危险性指数超20 a一遇时,预计受灾人口将达12万人以上。

     

The “easy restriction” syndrome drive local fish stocks to extinction: The case of the management of Swedish coastal populations

Spatially sensitive management built on detailed biological and socio-economic knowledge is required to establish sound fishing regulations and to avoid extinction of small coastal populations of fish and shellfish. Highly productive isolated populations of several commercial species have historically inhabited the Swedish west coast, but during the past century these populations have been depleted by fisheries and with no sign of recovery. Since 1999 several fisheries regulations and different stakeholder co-management initiatives have flourished along the Swedish coast of the Skagerrak. They aimed to facilitate the recovery of collapsed local stocks but the established regulations failed to identify and restrict the main sources of mortality acting on local stocks and they have thus been ineffective to promote the recovery. Furthermore, regulations have operated on the weakest among stakeholders (e.g.. recreational fishers), which have minor influence over management, and the restrictions have been imposed without providing any data which supported the choice (i.e. the “easy restriction” syndrome). In line with the general “spirit” of recent Swedish fishery management, we conclude that managers, without the disapproval of Swedish scientists, have circumvented limitations which should address the largest mortality factor, i.e. the commercial fishery. The regulations presently in place, have been politically uncontroversial and easy to implement, but have been highly unsuccessful. We therefore suggest that stakeholders, including politicians, should start focusing on more effective and science-based management and less on what is politically attractive if Swedish citizens shall have a chance to witness the recovery of their once flourishing coastal populations.