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821.
The Gross growth efficiency(GGE) is defined as the amount of consumer carbon produced relative to the amount of prey ingested in a given time interval. In population ecology, it can be considered as an index for the ability of a consumer to convert the biomass of food into its population production. In this study, it was firstly applied to estimate the role of amphipods grazing in the biomass dynamics of macroalgae(Ulva lactuca) in Yundang Lagoon(a subtropical eutrophic coastal lagoon, Xiamen City, China). It was found that amphipods were the dominant group(82.2%–98.7%) in the benthic assemblage, in which five amphipod species(Corophium uenoi, Ampithoe valida, Grandidierella japonica, Grammaropsis laevipalmata and Caprella panantis) were observed in the lagoon. However, only A. valida significantly consumed U. lactuca among these amphipod species. A series of experiments were conducted to estimate the consumption of U. lactuca by A. valida. It was suggested that the monthly secondary production(P) of A. valida using size frequency method ranged from 2.39 to 13.68 g/m2. GGE of A. valida exponentially reduced with body size and was closely associated with water temperature. Therefore, GGE equation for different months using the temperature recorded during the field investigation was fitted. The monthly consumption of U. lactuca was figured out to be 86.7–1 549.0 g/m2 by the sum of consumption(P/GGE) by A. valida at different size, accounting for 2.0%–37.5% of U. lactuca production. It indicates that the grazing effect of A. valida did play a role in reducing the accumulation of U. lactuca biomass when A. valida was abundant, but it finally fails to limit the U. lactuca growth in Yundang Lagoon. Low abundance of A. valida and high nutrient loading may be two major reasons for the outbreak of U. lactuca bloom in the lagoon.  相似文献   
822.
近年来北部湾沿岸产业的快速发展对海湾特别是潮间带的生态环境造成一定的污染压力。双壳类动物对重金属有极强的富集能力,其体内的重金属含量是海洋污染监测的重要指标。根据2011年春季北部湾潮间带的波纹巴非蛤(Paphia undulata)软组织中7种重金属(Hg、Cd、Pb、Cr、Cu、Zn、As)的测定结果,分析该区域蛤体内重金属的空间分布特征。通过计算单因子标准指数(Pi)、金属污染指数(MPI)、生物-沉积物积累因子(BSAF)、重金属周最大理论摄入量(TMWI),评价波纹巴非蛤对沉积物中重金属的积累特征、生物质量及食用风险。研究表明,波纹巴非蛤体软组织中重金属污染总体水平不高,但站位间差异明显;该生物对沉积物中不同种类重金属的积累能力不同,对Cd、Hg、Zn的积累能力高于Pb、Cr、Cu、As;计算得到的各种重金属周最大理论摄入量(TMWI)均远低于食品添加剂联合专家委员会(JECFA)规定的相应限值,造成食用风险的可能性较低。  相似文献   
823.
To date, efforts by non-governmental organizations to encourage reduced meat consumption in light of climate change have been quite limited, particularly among environmental non-governmental organizations. This study sought to examine the factors influencing non-governmental organization decisions to establish and sustain dedicated public education and/or policy advocacy campaigns on this issue. More specifically, a grounded theory approach was used to examine environmental, food-focused, and animal protection non-governmental organizations in the U.S., Sweden, and Canada. Results indicate that the relatively limited degree of engagement is primarily attributable to the fact that few non-governmental organization staffers felt that addressing meat consumption within a climate change context was a part of their core missions. Reduced meat consumption was also seen as an issue with limited social and political appeal. Further, many environmental non-governmental organizations appeared to be reluctant to mount campaigns explicitly encouraging personal behavior change of any type. Cross- non-governmental organization collaboration or the creation of additional non-governmental organizations with missions focused on this specific issue may be needed to increase the level of campaigning on this issue.  相似文献   
824.
房产测绘是房地产产权户籍管理中一项非常重要的工作,房产测绘应结合新的建筑设计规范和建筑施工新工艺、测绘新技术的要求,逐步完善房产测绘技术标准,使其更具可操作性,以解决房产测绘中实际可能出现的新问题。本文对房产测量中房屋面积测算过程中经常碰到的几个问题进行探讨,并提出一些自己的意见建议。  相似文献   
825.
目前,全国许多地方的房产测绘工作在执行《房产测量规范》GB/T 17986.1-2000基础上,还额外执行地方发布的房屋建筑面积测绘计算规范,本文通过研究和分析房产测量规范和北京、上海、广州、深圳四个城市制定的房屋建筑面积计算方法,发现上述地方在执行房产测量规范中存在较大差异。  相似文献   
826.
High quality infrastructure is crucial to economic success and the sustainability of society. Infrastructures for services, such as transport, energy, and water supply, also have long lead times, and therefore require effective long-term planning. In this paper, we report on work undertaken as part of the UK Infrastructure Transitions Research Consortium to construct long-term models of demographic change which can help to inform infrastructure planning for transport, energy, and water as well as IT and waste. A set of demographic microsimulation models (MSM), which are spatially disaggregate to the geography of UK Local Authorities, provides a high level of detail for understanding the drivers of changing patterns of demand. However, although robust forecasting models are required to support projections based on the notion of ‘predict-and-provide,’ the potential for behavioral adaptation is also an important consideration in this context. In this paper, we therefore establish a framework for linkage of a MSM of household composition, with behavior relating to the consumption of energy. We will investigate variations in household energy consumption within and between different household groups. An appropriate range of household types will be defined through the application of decision trees to consumption data from a detailed survey produced by the UK Department of Energy and Climate Change. From this, analysis conclusions will be drawn about the impact of changing demographics at both household and individual level, and about the potential effect of behavioral adjustments for different household groups.  相似文献   
827.
Geographic applications frequently require the gathering and analysis of socioeconomic data. For many nations, these data are normally collected through a census. However, during the intercensal period (5–10 years), these data lose their currency and must be updated. The objective of this project was to estimate housing unit density from Landsat ETM+ imagery in the Terre Haute, IN, USA, region. Modelling was done for 1945 census blocks in the study area containing 30 972 housing units. Landtype, as represented by six cluster classes, was used as the primary surrogate for housing unit density. The percentage of each landtype within the census blocks was calculated. Other landscape metrics representing landtype patch dominance and diversity were also calculated on a per-block basis. Housing unit density within the census block was then modelled as a function of those percentages and metrics using discriminant analysis and multiple regression. The simple correlation between the observed and modelled housing unit density was 0.79. The mean residual error produced by the model was 0.37 housing units per hectare.  相似文献   
828.
《Urban geography》2013,34(4):296-323
This paper describes and analyses the geography and structure of the neighborhood residential preferences and residential satisfaction of the inhabitants of the medium-sized, post-Soviet city of Ust'-Kamenogorsk, Kazakhstan (population ca. 300,000). It is based on a questionnaire survey (N = 1516 + 320) conducted by the author in cooperation with the statistical authority of the Eastern Kazakhstan oblast'. At the aggregate level, the evidence that is presented suggests distinct preference patterns, and that the main focus of preference is on the city center. The geography of residential satisfaction is different. Differences in satisfaction have been found between residents of housing built by former high-priority enterprises and those occupying most of the remainder of the housing stock. These differences underscore the pervasive and continuing importance of the legacy of Soviet economic and territorial planning, and the still rather limited changes that the marketization of the economy has been able to produce.  相似文献   
829.
《Urban geography》2013,34(7):565-567
Through a close examination of the case of Virginia v. Hicks—from Kevin Hicks's arrests for trespassing on streets near a Richmond, Virginia, public housing project in 1998 and 1999 to the unanimous Supreme Court decision upholding these arrests on the grounds that no harm was done to the First Amendment—this paper explores how the rights of private property are made, through the judicial process, to "trump" other kinds of rights and interests. It examines the implications of both dominant property practices and discourses and a more general judicial anti-urbanism for city life. The paper shows that one of the things at risk given the judiciary's love affair with private property rights is the right of some people simply to be present in public space. By implication, the paper argues that legal geographies need to examine more than just final court decisions (as is often the case), but also uncover the full legal history—the strange twists and turns—of the cases examined.  相似文献   
830.
《Urban geography》2013,34(1):91-94
This study disentangles the relationship between income and real estate value development in Dutch urban neighborhoods. Within the literature on upgrading and downgrading, it is often assumed that neighborhood income and real estate value development are strongly linked. The results reported here—based on research in Amsterdam, The Hague, and Tilburg—indicate that income and real estate values develop simultaneously in only a relatively small number of neighborhoods, which are at the top and bottom of the housing market hierarchy. The majority reveal a more complex relationship: a number of neighborhoods show a time lag between the trends, whereas in other neighborhoods income and real estate values show partially diverging trends. Several tentative explanations are offered for the complex relationship, and stress the importance of place-specific knowledge. Three points of attention are suggested for further research: understanding the role of household dynamics, the position of neighborhoods within their urban system, and the role of the state and housing associations in neighborhood change.  相似文献   
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