Fecundity of the snapper Chrysophrys auratus (Pisces: Sparidae) from the Hauraki Gulf     

James Crossland 《新西兰海洋与淡水研究杂志》2013,47(4):767-775

Fecundity estimates were made for snapper Chrysophrys auratus, a serial spawning fish, for the 1974–75 and 1975–76 spawning seasons. Weighed sub‐samples of ovaries were used, and eggs were counted manually. All eggs >0.1 mm diameter were considered potentially capable of being spawned; estimates of these eggs were made at the beginning and end of spawning, and their difference was considered to be the actual fecundity. A log‐log transformation of egg numbers against length offish gave a linear relationship. Fecundity estimates ranged from 297 000 at 25 cm to 4 528 000 at 50 cm in 1974–75, and from 83 000 at 25 cm to 6 164 000 at 50 cm in 1975–76. Counts of ripe eggs were also made, and batch sizes ranging from 13 000 at 25 cm to 104 000 at 50 cm were predicted. By combining these data with fecundity estimates the number of batches spawned was estimated to be 23–44 in 1974–75, depending on and increasing with length; and 6–59 in 1975–76.  相似文献   

雷达发射机固态调制器的设计与实现     

贺美萍  ;王庆有  ;王冰利 《内蒙古气象》2013,(5):40-42

发射机是701系列探空雷达的重要组成部分,具有频率高、电压高、功率大、脉冲宽度窄等特点。原701雷达调制器和控制电源是由电子管和大型变压器等组成,成本高、故障率高、维修不便。新研制的固态调制器集控制电源于一体,通过采用推挽放大电路,多个场效应管并联电路及脉冲升压变压器,即克服了半导体器件存在的缺点,又实现了调制器的功能。  相似文献   

Introduction: Rethinking Practices for Enhancing Diversity in the Discipline     

Patricia Solís  Ines M. Miyares 《The Professional geographer》2013,65(2):169-172

This study explores the variations in household participation rates in recycling projects implemented in urban and suburban communities. A causal model is developed to compare the demographic attributes of residents, their awareness of the recycling programs, their environmental attitudes, and their overall willingness to recycle. The model is assessed by Linear Structural Equations Methodology (LISREL). The results suggest that household recycling behavior is not consistent across communities due primarily to variations in demographic characteristics of residents and their evaluation of program policies.  相似文献   

GLOBAL sensitivity analysis,GIS and multi‐criteria evaluation for a sustainable planning of a hazardous waste disposal site in Spain     

M. Gómez‐Delgado  S. Tarantola 《International journal of geographical information science》2013,27(4):449-466

A novel application of Sensitivity Analysis is presented. Useful applications of Global SA (GSA) already exist in the field of numerical modelling. In this paper, we explore the joint use of GSA, Geographical Information Systems (GIS) and Multi‐Criteria Evaluation. In this preliminary case study, 11 factors have been used to find the best place to locate a hazardous waste landfill. Two variance‐based methods (Sobol' and E‐FAST) are used to compute sensitivity indices in order to identify the factors that determine the variance of the model output. The results show that only three factors jointly account for 97% of the output variance. This information is employed to make a simplification of the original model, retaining only these three influential factors. In addition, if the SA is carried out in a pilot area where the spatial properties are similar to those of the whole region, we can infer the results to the whole area. This procedure achieves the goal of the study with an optimized allocation of resources for GIS data acquisition.  相似文献   

GIS,multi‐criteria and multi‐factor spatial analysis for the probability assessment of the existence of illegal landfills     

Giancarlo Biotto  Lucia Gobbo  Elisa Furlan  Sonia Valenti  Roberto Rosselli 《International journal of geographical information science》2013,27(10):1233-1244

This work deals with the identification of potentially contaminated areas using remote sensing, geographic information systems (GIS) and multi‐criteria spatial analysis. The identification of unknown illegal landfills is a crucial environmental problem in all developed and developing countries, where a large number of illegal waste deposits exist as a result of fast, and relatively unregulated, industrial growth over the past century. The criteria used to perform the spatial analysis are here selected by considering the characteristics which are ‘desirable’ for an illegal waste disposal site, chiefly related to the existence of roads for easy access and to a low population density which facilitates unnoticed dumping of illegal waste materials. A large dataset describing known legal and illegal landfills and the context of their location (population, road network, etc.) was used to perform a spatial statistical analysis to select factors and criteria allowing for the identification of the known waste deposits. The final result is a map describing the likelihood of an illegal waste deposit to be located at any arbitrary location. Such a probability map is then used together with remote sensing techniques to narrow down the set of possibly contaminated sites (Silvestri and Omri, 2008 Silvestri, S. and Omri, M. 2008. A method for the remote sensing identification of uncontrolled landfills: formulation and validation.. International Journal of Remote Sensing, 29(4): 975–989. [Taylor & Francis Online] , [Google Scholar]), which are candidates for further analyses and field investigations. The importance of the integration of GIS and remote sensing is highlighted and represents a key instrument for environmental management and for the spatially‐distributed characterization of possible uncontrolled landfill sites.  相似文献   

Mapping illegal domestic waste disposal potential to support waste management efforts in Queensland,Australia     

Katharine Glanville  Hsing-Chung Chang 《International journal of geographical information science》2013,27(6):1042-1058

Illegal disposal of waste is a significant management issue for contemporary governments because of the hazards posed to both human and ecosystem health. Understanding the complex distribution pattern of illegal waste and the range of economic, environmental and social factors influencing this distribution is valuable for improving the effectiveness and efficiency of waste management efforts. This article examines the applicability of mapping illegal waste disposal in the Sunshine Coast (Queensland, Australia) through the identification and integration of predictive spatial data in a geographic information system. A statistical model of illegal waste disposal was developed using a binary logistic regression analysis to identify explanatory variables suitable for predicting the distribution of illegal waste. Five statistically significant explanatory variables were identified through this analysis: population density, primary land use, distance to the nearest road, waste facility and roadside amenity. The generated statistical model had a predictive success of 86.1% with all indicators suggesting good model fit (χ² = 474.3, P = 0 with df = 22) across the study area. Standardised spatial data on each explanatory variable were combined using a weighted linear combination analysis and the results were classified into five categories from very low to very high illegal waste disposal potentials using the equal interval method. The resultant mapping identified 6.9% of the study area as having very high illegal waste disposal potential, and subsequent validation indicated that 32.9% of known illegal waste disposal sites were located within these areas.  相似文献   

中国餐饮业食物浪费的资源环境问题综述     

高利伟  成升魁  曹晓昌  张丹  刘晓洁  秦奇  刘尧 《资源与生态学报(英文版)》2013,(4):337-343

近年来食物浪费以及食物浪费的资源环境问题越来越成为全球关注的焦点,尤其是在发展中国家,食物浪费成为威胁食物安全的另一关键因素。尽管如此,在中国,人们仍然对食物浪费缺乏认识,尤其是餐饮业中消费者的食物浪费。因此,基于国内主流媒体报道的大量餐饮业食物浪费的案例数据资料,本研究针对餐饮业中的食物浪费做了系统的阐述。针对餐饮业食物浪费的初步估计,本研究揭示了我国餐饮业食物浪费的严重性。通过分析国际上大量食物浪费的相关文献资料,本研究具体阐述了食物浪费的资源环境代价。最后,本研究基于生命周期评价方法提出了针对餐饮业食物浪费及其资源环境效应研究的概念框架,以便更有效地减少食物浪费。  相似文献   

Geotechnical Engineering Issues in Ocean Waste Disposal: A Review     

Kenneth R. Demars 《Marine Georesources & Geotechnology》2013,31(3):219-235

Marine pollution has received considerable attention during the past few years as the news media has focused on such topics as contaminated seafoods, algae blooms, fish and mammal kills, and dirty beaches. The source of these pollution problems are many and include: sewage outfalls, industrial discharges, storm runoff from agricultural lands and metropolitan areas, waste sludges, dredge materials, and highly concentrated chemical and radioactive wastes. Although the United Nations has banned marine dumping, there is still the problem of legacy wastes and low level discharges into the coastal zone. Disposal of these wastes in the marine environment typically involves either: their placement directly on or within the seabed or dilution in the water column. If wastes are diluted in the water column, they have the potential to be adsorbed onto the surface of sediment particles which are settling to the seabed. As particles settle through the water column they are subjected to extensive dispersal and may eventually be injested by bottom-feeding organisms or bio-accumulation by plankton and, thus, enter the food chain. Geotechnical engineers working as members of multidisciplinary teams apply quantitative knowledge about the behavior and physical performance of earth materials toward designing systems for disposing of these wastes in the oceans and aid in monitoring waste disposal sites. In dredged material disposal geotechnical engineers assist in selecting disposal equipment, predict stable characteristics of dredged material mounds, design mound caps, and predict erodibility of the material. With sewage outfalls, geotechnical engineers design foundation and anchor elements, estimate scour potential around the outfalls, and determine the stability of deposits made up of discharged materials. Geotechnical engineers also consider the influence that pollutants have on the engineering behavior of marine sediment and the extent to which changes in behavior affect the performance of structures founded on the sediment. In each of these roles, careful application of geotechnical engineering principles can contribute toward more efficient and environmentally safe disposal operations.  相似文献   

缓冲／回填材料——砂-膨润土混合物研究进展   总被引：1，自引：0，他引：1  

叶为民  王琼  陈永贵  陈宝 《铀矿地质》2010,26(2):95-100

砂-膨润土混合物已被很多核能国家选为核废物地质处置库中理想的缓冲/回填材料。膨润土中加入砂可提高热传导系数和强度,维持适当的膨胀力,使其工程上易于处理并节省成本;但同时会导致其阻水能力和自愈性减弱。研究表明,影响砂-膨润土混合物以上各性质的主要因素为：砂/膨润土配合比、初始含水量、干密度等,它们综合决定着砂/膨润土最优配合比的选取。石英砂对混合物的渗透性、热传导性、强度等的影响,最优配合比选取,以及非饱和状态下吸力变化对混合物渗透性的影响等,应该是今后一段时间内砂-膨润土混合物研究的重点。  相似文献   

利用Welch功率谱估计方法求埋深的参数选择   总被引：1，自引：0，他引：1  

耿美霞  杨庆节 《吉林大学学报(地球科学版)》2010,(Z1)

研究了采用Welch谱估计方法求异常体埋深时,窗函数类型、窗口长度、FFT点数、重叠采样点数对结果的影响;应用Matlab中的PSD函数,以无限长水平圆柱体为例作了分析。根据分析结果,提出了采用Welch谱估计方法计算异常体埋深时,关于窗函数、窗长度、FFT点数和重叠采样点数选择的建议。  相似文献