Diversity and conservation status of large branchiopods (Crustacea) in ponds of western Poland

A survey on temporary ponds has been conducted in search for large branchiopod crustaceans (Anostraca, Notostraca, Spinicaudata and Laevicaudata) in Wielkopolska province (western Poland). 728 pools have been studied and large branchiopods have been found in 221 of them. Seven species have been recorded, including three anostracans: Branchipus schaefferi, Chirocephalus shadini and Eubranchipus grubii; two notostracans: Lepidurus apus and Triops cancriformis; one spinicaudatan, Cyzicus tetracerus and one laevicaudatan, Lynceus brachyurus. According to the analysis of co-occurrence, the species form three groups, differing in habitat preferences and conservation status. The number of species shows that the diversity of globally threatened large branchiopods is still relatively high in the region. On the other hand, their conservation status is highly diverse and in most species unfavourable. Distribution of all species is highly clustered: large branchiopods have been generally found in 33 UTM squares (10 × 10 km) of 96 squares studied. However, only two species, i.e. E. grubii and L. apus occurred in more than five such squares and could be assessed as moderately widespread. Most water bodies inhabited by large branchiopods occur in groups forming patches of suitable habitats which are dispersed among prevailing seemingly unsuitable areas. Sustaining the existence of large metapopulations seems, therefore, to be essential for conservation of branchiopod species diversity. Field observations also bring some examples of human activities unintentionally supporting the branchiopod conservation.     

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毛乌素湖盆滩地湖水与地下水交互作用分析

湖水与地下水交互作用对于水资源合理开发与利用有着重要意义.基于温度示踪的原理,采用解析法、数值法2种方法,分析了湖床底部埋深0～0.4 m湖水与浅层地下水交互关系,并与水动力学方法进行了对比.结果 表明,2018年5月20日至28日,湖水与地下水之间的垂向渗流速度为2×10-7～1×10-6 m/s,且在埋深0.4 m...     

2005―2006年间粤西云浮市大气降水化学特征

对2005―2006年间在粤西云浮市采集到的40场降水样品进行降水化学分析.结果表明,降水离子的平均浓度为730.62 μeq/L,高于云南丽江、青海瓦里关山、香港、广东广州和鹤山等地,大气污染比较严重;降水中主要阳离子成分是Ca2+和NH4+,阴离子成分是SO42?和NO3?,共占离子总浓度的83﹪;离子浓度高值出现在降水偏少的汛期过渡期,低值则发生在降水丰沛的前汛期、主汛期和台风雨期;云浮降水离子浓度受地壳来源、工业交通污染影响较大,海洋源影响较小.     

基于SMOS的黄土高原区域尺度表层土壤水分时空变化

用SMOS土壤水分数据、MODIS植被指数数据和TRMM月降水数据,通过对黄土高原区域尺度表层土壤水分含量时空变化的研究,对表层土壤水分的时空变化特征及其对降水的响应进行了分析。结果表明：黄土高原表层土壤水分空间分布主要表现为西部和东北部低、东南部较高。青海石质高山区及山西西南部等区域土壤水分含量与整个区域存在差异。黄土高原西部与河套平原部分区域表层土壤水分含量季节性变化较大。在不同降水条件下,土壤水分含量与降水量相关性呈显著差异。     

基于粗糙集理论的区域降雨型滑坡预测预报

选择四川省雅安市雨城区为研究区域,以该区降雨型滑坡为数据样本,结合粗糙集理论,提取了研究区域的降雨因子和地质因子作为条件属性因子,利用粗糙集的计算机挖掘和智能知识发现功能,分析得到了预测降雨型滑坡发生与否的有价值的规则集。所生成的决策规则能够实现该区域滑坡的预测预报。研究结果表明:本方法较传统的统计方法更符合降雨型滑坡预测的非线性关系,而且考虑了地质因素的影响,较单纯降雨阈值的预测方法有更高的空间分辨率。     

Morphologies of eumelanins from the ink of six cephalopods species measured by atomic force microscopy

The morphologies of eumelanin, isolated from the six cephalopods species Sepia esculenta, Sepia lycidas, Sepia pharaonis, Sepiella japonica, Euprymna berryi, and Uroteuthis (Photololigo) edulis, were investigated using atomic force microscopy (AFM). The results showed that the hierarchical aggregate structures of irregular spherical particles with different diameters are the common characteristics of these eumelanins. Furthermore, the diameters of these spherical particles present an uneven distribution in a wide range and mainly concentrate in the range of about 20-150 nm. In addition, the eumelanin from different cephalopods species show obvious differences in the morphologies, which is illustrated by different assembly forms of diverse aggregate units and the quantitative features of eumelanin particles derived from the images.     

Risk assessment of human neural tube defects using a Bayesian belief network

Neural tube defects (NTDs) constitute the most common type of birth defects. How much risk of NTDs could an area take? The answer to this question will help people understand the geographical distribution of NTDs and explore its environmental causes. Most existing methods usually take the spatial correlation of cases into account and rarely consider the effect of environmental factors. However, especially in rural areas, the NTDs cases have a little effect on each other across space, whereas the role of environmental factors is significant. To demonstrate these points, Heshun, a county with the highest rate of NTDs in China, was selected as the region of interest in the study. Bayesian belief network was used to quantify the probability of NTDs occurred at villages with no births. The study indicated that the proposed method was easy to apply and high accuracy was achieved at a 95% confidence level.     

交通轴线约束下的中国区域经济分布特征

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国外非正规部门研究进展

国外非正规部门的研究始于20世纪70年代,最初研究的对象主要集中在发展中国家和地区,随着研究的深入,发现发达国家和地区也存在非正规部门,但存在方式和形成机制有别于发展中国家和地区.通过对国外非正规部门研究文献的系统梳理和分析,表明国外非正规部门的研究已形成一定的研究体系和理论成果,研究内容主要涉及非正规部门的边缘性和异质性等特征,非正规部门的空间集聚与分异,非正规部门存在与发展的理论,包括贫困就业论、二元经济论、规制论和嵌入论等,非正规部门与正规部门的联系,非正规部门的经济、社会影响以及非正规部门的正规化与政策等方面.但在从事非正规经济活动的人的空间特征、从综合视角分析非正规部门的形成发展过程、非正规部门对地域空间的影响以及对比研究和定量研究方面还较为欠缺.