Women participation in formal decision-making: Empirical evidence from participatory forest management in Ethiopia

Amid growing emphasis on community-based approaches to natural resource management, there are concerns about the lack of women participation in communal decision-making. We analyze the association between participation of women in decision-making of forest user groups in Ethiopia and several forest management outcomes. We combine longitudinal survey, administrative and forest inventory data and find that participation of women in executive committees (i.e., formal decision-making) is associated with greater forest benefits, and an improved (perceived and actual) condition of the forest. Alternatively, the association between women participation in group-level meetings and outcomes is not robust. This implies that women participation in formal decision-making is required to reach forest conservation and livelihood gains.     

长毛对虾酸性磷酸酶功能基团的研究(Ⅱ)

用化学修饰剂pCMB、NBS、K试剂修饰长毛对虾Penaeuspenicilla－tusAlcock酸性磷酸酶（ACPase，EC3．1．3．2），在修饰剂作用下，酶活力明显下降，健康虾酶对修饰剂的敏感性（NBS除外）大都稍大于病虾酶。修饰酶的紫外280um吸收光谱以及荧光340um发射光谱的变化，表明酶活力下降的同时酶构象也产生相应的变化。结果表明，酶分子的半胱氨酸残基、色氨酸残基以及门冬氨酸、谷氨酸β或γ验基与酶活力有关，是酶的催化功能基团。     

空间线群目标方向相似度计算模型

本文提出了3种空间线群目标方向相似度的计算模型。依据风向玫瑰图的原理,将空间线群目标的方向特征进行定量统计生成对应的方向玫瑰图,在此基础上,生成对应的标准差椭圆和统计直方图,从而分别建立基于线目标方向玫瑰图、基于标准差椭圆和基于统计直方图的方向相似度计算模型,并进行了实验验证和分析。     

临夏台地电阻率变化与震兆现象分析

以甘肃省临夏台1981年以来的地电阻率资料为基础,利用数理统计和相关分析方法,分析该台地电阻率的变化特征,探讨EW和NS两测向之间数据的相关性,以及与大夏河流量变化的对应关系,认为该台两测向数据间具有很高的相关性,可能与区域地下介质具有较均匀的电性结构有关;分析了该区降水和地下静水位对地电阻率的影响,认为地下静水位的影响更显著.此外,探讨了临夏台地电阻率资料作为地震前兆的意义,认为该台资料对甘东南及甘青交界地区的中强地震反应敏感,以下降型破年变异常为主,呈现出震级越大,异常持续时间越长的特点.该台资料同时对甘青地区成组中强地震有所反应,显示出异常持续时间长、幅度大和恢复慢的特点.     

有限群p-超可解性的一个判别准则

为了得出群的p-超可解性的一些判别准则,引入有限群的z-置换嵌入子群的概念。设z是群G的Sylow子群的完全集,群G的一个子群H称为在G内z-置换嵌入,如果H的每个Sylow子群也是G的某个z-置换子群的Sylow子群,一些已知的结论也得到推广。     

Observations on Chatham Rise currents

New Zealand stream ecosystems differ from many of their North American counterparts, on which general stream ecosystem models are based, in several ways. In New Zealand, large particle detritivores (shredders) are poorly represented, and the dominant invertebrates are browsers which feed on fine particulate organic matter and stone‐surface organic layers. In contrast with the river continuum concept of Vannote et al. (Canadian Journal of Fisheries and Aquatic Sciences 37: 130–137, 1980), representation of functional feeding groups shows little change downstream and a temporal continuum of synchronous species replacements is not found. Many common benthic invertebrates are ecologically flexible species with poorly synchronised life histories. These differences appear to be associated with the non‐retentive, climatically unpredictable nature of the stream environment. The idea that stream communities are highly structured entities is questioned, as is the generality of the river continuum concept.     

Observations of freak waves in random wave field in 2D experimental wave flume

Long time series of wave field are experimentally simulated by JONSWAP spectra with random phases in a 2D wave flume. Statistic properties of wave surface, such as significant wave height, skewness and kurtosis, are analyzed, and the freak wave occurrence probability and its relations with Benjamin-Feir index （BFI） are also investigated. The results show that the skewness and the kurtosis are significantly dependent on the wave steepness, and the kurtosis increases along the flume when BFI is large. The freak waves are observed in random wave groups. They occur more frequently than expected, especially for the wave groups with large BFI.     

Ethnic migration between area groups in England and Wales

Minority ethnic populations in England and Wales have been increasing steadily as a share of the total population since the 1991 Census. In this paper, we are interested in how internal migration has changed as a possible consequence. Our analysis focuses on the movements between 12 area groups, as defined by the Office for National Statistics, and addresses the following three research questions: (1) how has internal migration in England and Wales evolved from 1991 to 2004; (2) what are the main differences in the movements between the White (majority) population and the ethnic minority population; and (3) how do migration patterns differ when ethnicity, education and employment statuses are considered together? The data come from the 1991 to 2004 National Health Service Central Registers, the 1999–2004 patient registers and the 2001 Census. We find strong stability in the migration patterns of the total population over time. However, large differences appear when the flows are disaggregated by ethnicity and further by education and employment. Education level is an important factor influencing the migration patterns for the White population, whereas employment status is a much more important factor for the ethnic minority population.