Shell‐shape and morphometric variability in Mytilus galloprovincialis from micro‐tidal environments: responses to different hydrodynamic drivers          下载免费PDF全文

Vanessa Moschino  Monica Bressan  Luigi Cavaleri  Luisa Da Ros 《Marine Ecology》2015,36(4):1440-1453

Tidal conditions differently influence inter‐tidal organisms in terms of general physiological and metabolic responses. In this study we investigated the morphological response in shells of Mytilus galloprovincialis native to different micro‐tidal coastal environments in the Northern Adriatic Sea. Our purpose was to highlight the ecophenotypic variability across tidal levels and to elucidate how tidal currents and waves produced by anthropogenic activities may play a part in modulating shell morphology. Three sampling sites were selected: an open‐sea area 15 km off‐shore and two sites within the lagoon of Venice, the first near one of its three inlets, and the other one in the proximity of Venice city centre. At each sampling site, organisms were seasonally collected at different depths within their vertical zonation, either in the inter‐tidal zone – i.e. at both the highest and lowest tide zonation limits, and subtidally. The mussel shells were analysed by investigation of their morphometric relationships (height/length and width/length ratios) and by elliptic Fourier analysis of the shell contours. Shell thickness and condition index were also evaluated for a better comprehension of energy allocation/partitioning. Estimates based on long‐term measurements, visual observation, wind statistics and wave growth laws allowed an evaluation of the forces acting on shells. At the open‐sea site, the observed phenotypic variability of both shell shape and thickness was clearly related to the tidal vertical zonation. At the two lagoon sites, the currents generated by tidal flow through the inlet and the waves caused by the frequent passage of boats influenced both shell shape and thickness. A trade‐off between protection and growth was apparent along the tide gradient, as emphasized by the differences in the partitioning and allocation of energy between shell and flesh production.  相似文献   

Cu²⁺对青蛤的胁迫效应     

梁健  雷雅雲  李永仁  郭永军  邢克智 《海洋科学》2015,39(11):74-78

为研究青蛤(Cyclina sinensis)对重金属Cu~(2+)的蓄积作用及免疫机能的影响,开展了Cu~(2+)对青蛤的急性毒性实验,观察青蛤在96 h Cu~(2+)半致死浓度和安全浓度胁迫下,不同组织的蓄积趋势,及血淋巴液中SOD、CAT和ACP活性的变化。结果显示:Cu~(2+)的半致死浓度为0.807 mg/L,安全浓度为0.00807 mg/L。鳃和内脏团组织中蓄积的Cu~(2+)浓度与处理时间呈正相关;在半致死和安全浓度胁迫下,鳃组织中Cu~(2+)蓄积速度均快于内脏团;在半致死浓度胁迫下血淋巴液中SOD、CAT和ACP活性呈现先诱导再抑制的趋势,安全浓度下无明显变化,但均高于对照组水平。  相似文献   

Ultimate Load Capacity of Offshore Pipeline with Arbitrary Shape Corrosion Defects     

陈严飞  张娟  张宏  刘啸奔  李昕  周晶  曹静 《海洋工程》2015,29(2):241-252

A set of generalized solutions are proposed for estimating ultimate load capacity of pipeline with arbitrary corrosion shapes subjected to combined internal pressure, axial force and bending moment. Isotropic and anisotropic material characteristics in longitudinal and circumferential direction of pipeline are also considered in the proposed equations. Simplified numerical method is used to solve the generalized expressions. The comparisons of numerical results based generalized solutions and full-scale experimental results are carried out. The predicted results agree reasonably well with the experiment results. Meanwhile, the effects of corrosion shapes and locations on the ultimate load capacity are studied.  相似文献   

Inequalities, institutions, and forest commons   总被引：1，自引：0，他引：1  

Krister AnderssonArun Agrawal 《Global Environmental Change》2011,21(3):866-875

This paper contributes to a growing literature on the commons that examines the relationship between inequality and commons outcomes. Our analysis of evidence on forest commons outcomes in 228 cases from South Asia (India and Nepal), East Africa (Kenya and Uganda) and Latin America (Mexico and Bolivia) suggests that local governance and collective action matter in shaping how socioeconomic inequalities affect forest conditions. In particular, we find that both inter-group and intra-group economic inequalities have consistently negative effects on forest outcomes, but that effectively functioning local institutions for collective action dampen the negative effect of inter-group inequality on forest outcomes.  相似文献   

气候变化适应行动实施框架——宁夏农业案例实践     

居煇  陈晓光  王涛明  姜帅 《辽宁气象》2011,(1):58-64

宁夏是我国生态脆弱区和贫困区之一,以宁夏为例开展农业适应行动实践具有一定的代表性和示范作用。根据气候变化适应行动实施框架,研究结果表明：宁夏未来气候干旱风险将增加,水资源短缺矛盾加剧,极端气候事件频率和强度加大。未来宁夏北部灌区农业应以发展节水灌溉和高效种植为主,中部以设施农业和牧业为主,南部以发展特色农业为主。气象部门和水利部门对适应技术的适应效果持乐观态度,农牧业部门和林业部门则态度谨慎。适应措施能否实施的首要条件是措施符合国家和地方的政策方针,其次是成本效益;在实施条件中,要求相对比较弱化的是公众对气候风险的认知程度以及措施的灵活调整性。在适应措施选择上,气象服务和种植结构调整成为首选的适应技术,而覆盖技术、节水技术由于更倾向于传统的技术范畴,虽然效果较好,但对其适应优先性选择存在影响。  相似文献   

山东省地层划分对比厘定意见   总被引：5，自引：0，他引：5  

张增奇  刘书才  杜圣贤  单伟  程光锁  张尚坤  张义江  张成基  宋明春  焦秀美  王世进  杨恩秀  宋志勇  王立法  许克民 《山东国土资源》2011,27(9):1-9

山东省地层大部属华北地层大区晋冀鲁豫地层区,再分为华北平原、鲁西及鲁东三个地层分区,鲁东南海域日照市平岛、达山岛及车牛山岛等属华南地层大区扬子地层区连云港地层分区。岩石地层分为27个(岩)群120个(岩)组12个正式段,还有相当数量的非正式段。恢复奥陶纪东黄山组、北庵庄组、土峪组、五阳山组、阁庄组、八陡组,并6个组为马家沟群;恢复二叠纪黑山组、万山组、奎山组和孝妇河组,并4个组为石盒子群;在青州—临朐地区识别出奥陶纪亮甲山组。地质代号原则上遵从最新的国家标准及行业标准。  相似文献   

GENDER,GEOPOLITICS, AND GEOSURVEILLANCE IN THE BOURNE ULTIMATUM*     

KLAUS DODDS 《Geographical review》2011,101(1):88-105

Generic action‐thriller films, especially The Bourne Ultimatum, the last in a series of three films, provide a useful resource for examining the gendered nature of geopolitics, the specification of place, and the role of geosurveillance in post‐9/11 national security. Using the dialogue of the film as key source material, I show how the private world of Jason Bourne, an assassin, is interwoven with the public sphere of international security, including covert operations: The personal is geopolitical. I conclude with some reflections on how we might use film as a critical pedagogical resource.  相似文献   

空间网与地面网联合平差数据处理方法注     

成英燕  程鹏飞  秘金钟  顾旦生  张莉 《测绘科学》2004,29(2):57-59,63

针对联合平差数十万个观测值 ,近 2 0万个未知数来说 ,如何有效地组织数据 ,管理数据 ,最大限度地压缩内存是联合平差数据处理的关键。本文主要讨论联合平差数据处理中的主要函数模型和随机模型、大规模稀疏矩阵有效的解算方法并用软件加以实现。作为实例用此软件对小范围的实验区数据进行平差 ,对其解算结果进行了分析  相似文献   

高分辨率遥感图像最近邻模糊分类器的研究及实现     

朱国龙  汪云甲  乔浩然  刘乐乐  赵一清 《测绘科学》2010,35(6):96-98

本文针对高分辨率遥感影像快速高效萃取有用信息这一遥感技术应用的热点问题,探讨了一种适合于组合特征识别的遥感图像最近邻模糊分类器。该分类器首先把待识别目标的组合特征与训练模板中的组合特征样本的平均值一一进行比较,从而得到了一个特征差矩阵。用模糊分布函数在同类特征差之间进行处理,生成一个隶属度矩阵,然后用算术平均法对隶属度矩阵进行处理,并用最大隶属度准则来进行分类判决。以新疆和静县的SPOT5图像为例,应用此方法对其进行分类试验。结果表明:利用此分类方法对SPOT5遥感图像进行分类,不仅使分类结果具有丰富的语义信息,而且克服了由于特征选择的不稳定性对分类结果的影响,分类精度也得到了显著的提高。  相似文献   

利用已有像控点的多期航空影像光束法区域网联合平差   总被引：1，自引：0，他引：1  

王建梅  朱紫阳 《测绘学报》2010,39(1):22-27

为了充分利用已有航空影像与控制成果,节约作业成本,缩短作业周期,提出一种利用已有像控点联合多期航空影像进行整体平差加密的数学模型,并采用我国南方某地区的数据资料进行了试验证明。结果表明,联合平差能将已有像控点的控制作用通过多期影像间的同名点传递到最新航空影像上,联合平差加密点的平面精度与常规光束法区域网平差加密精度基本一致,而高程精度则取决于多期影像间同名点的观测值个数,同名点观测值越多,加密点高程精度越高,因此只要多期影像间存在足够多的同名点观测值,则联合平差的加密精度完全能够满足摄影测量地形图测绘的生产需要。  相似文献