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61.
Since the mating of the parasitoid wasp Melittobia australica occurs on their eclosed hosts, the sex ratio is predicted to follow the local mate competition (LMC) theory. However, while LMC models predict that the sex ratio will increase from female-biased toward a 1:1 ratio with an increase in the number of foundresses, the observed female-biased sex ratios (1–5% males) show little increase in response to an increased foundress number. Lethal combat among adult males may serve as an explanation for this observed phenomenon. Using a microsatellite DNA marker, we first examined the individual sex ratio of two foundresses who had sequentially parasitized the same host. Both foundresses produced an extremely female-biased clutch and the sex ratios of the second foundress were only slightly less biased than that of the first. A small number of sons from both foundresses emerged at a constantly low rate over a prolonged period, resulting in a temporal mixture of emerging males derived from both the foundresses. Second, we conducted a one-on-one arena experiment to examine the combat level in relation to the relatedness of the opponents. Almost all the later-emerging males were killed by previously eclosed males irrespective of whether they were sibs or non-sibs. These results suggest that each foundress should not produce males in a single burst, but continue to produce male eggs at a constantly low rate in order to avoid the high mortality of her own sons by lethal male-male combat. This combat may be one of factors in explaining the extremely female-biased sex ratio even with an increasing foundress number.Communicated by R.F.A. Moritz 相似文献
62.
Agustin Robles-Morua Alex S. Mayer Mary H. Durfee 《Environment, Development and Sustainability》2009,11(1):197-213
There is a growing recognition in developing countries that community participation in water and sanitation projects is a
necessary strategy in sustainable development. The main advantage of following such an approach is that, if participation
can encourage a sense of ownership of the projects, the benefits of the project are more likely to extend over the long term.
The case study at hand focuses on the challenges faced in implementing a wastewater treatment system to solve an environmental
and public health problem in a rural community, Rosario de Tesopaco, in northwest Mexico. Until recently, the community has
been unable to implement an effective plan to treat the wastewater generated in the community. The problems faced by the community
can be attributed to the political arrangement of water and sanitation decentralization in Mexico that occurred in the mid
1980’s, whereby communities were required to meet wastewater treatment standards, but were not given the technical and political
guidance needed to achieve this goal. However, in this instance, cooperation between the authorities in Rosario de Tesopaco,
the federal agency for social development, and an academic institution has led to the successful design and approval of a
wastewater treatment project. This achievement can be attributed to the use of an effective collaborative strategy, tailoring
the project to the needs and capacity of the local community, positioning the community as the leaders and owners of the project.
A model for following this strategy for developing rural sanitation projects in Mexico is proposed.
Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
63.
Preventing groundwater contamination is vastly cheaper than remediation. Recognizing this, attention in water and land management
agencies in North America increasingly turn to groundwater protection. Local agencies, such as municipalities and watershed
management districts, are vital to successful groundwater protection, but they face daunting challenges. In the United States,
senior governments have recognized these challenges and provide considerable support for local agencies. In Ontario, Canada,
local agencies are, to a much greater extent, on their own. The aims in this paper are to analyze factors that shape local
capacity for groundwater protection, focusing on Ontario, and to recommend avenues for capacity building. Interrelationships
among five dimensions of capacity (technical, financial, institutional, social, and political) are explored through an analysis
of three smaller Ontario communities: City of Guelph (population 93,400), Town of Orangeville (population 22,188), and Town
of Erin (population 11,000). Size clearly influences capacity for groundwater protection. However, other considerations unrelated
to size appear to be as important. These other factors include the ability to form horizontal and vertical linkages with external
agencies, political leadership and commitment, and citizen involvement. Thus, smaller communities in Ontario (and other jurisdictions
with limited senior government support) would do well to focus on these areas at the same time as they develop their technical,
financial, and institutional capacity. 相似文献
64.
C. -H. Lee 《Resources, Conservation and Recycling》1998,24(3-4)
A resource depletion index can serve as a quantitative tool to evaluate the level of depletion for natural resources. This study introduces two types of resource depletion indices, the global resource depletion index and the local resource depletion index. Global resource depletion index mainly concerns global reserves and the annual consumption rate of these resources. The local resource depletion index not only considers global reserves and their annual consumption rate, but also considers the local factors such as local reserves, local recycling rates, and local resource import characteristics. This study considers the local resource characteristics of Taiwan and develops calculations for local resource depletion indexes for the resources of cobalt, molybdenum, tungsten, copper, aluminum, lead and zinc. 相似文献
65.
A GIS-based protocol for the collection and use of local knowledge in fisheries management planning 总被引:1,自引:0,他引:1
Despite a heavy reliance on scientific knowledge as the primary source of information in resource management, many resources are in decline, particularly in fisheries. To try and combat this trend, researchers have drawn upon the knowledge of local resource users as an important supplement to scientific knowledge in designing and implementing management strategies. The integration of local knowledge with scientific knowledge for marine species management, however, is problematic stemming primarily from conflicting data types. This paper considers the use of spatial information technology as a medium to integrate and visualise spatial distributions of both quantitative scientific data and qualitative local knowledge for the purposes of producing valid and locally relevant fisheries management plans. In this context, the paper presents a detailed protocol for the collection and subsequent use of local knowledge in fisheries management planning using geographic information systems (GIS). Particular attention is paid to the use of local knowledge in resource management, accuracy issues associated with the incorporation of qualitative data into a quantitative environment, base map selection and construction, and map bias or errors associated with the accuracy of recording harvest locations on paper map sheets, given the complications of map scale. 相似文献
66.
Masaaki Fukushima Misao Shioya Keiji Wakai Hidetoshi Ibe 《Journal of Material Cycles and Waste Management》2009,11(1):11-18
Sapporo Plastics Recycling Co., Ltd., (SPR) started its commercial operation of waste plastics liquefaction in 2000. At first
only hydrocarbon oil was reclaimed, this being derived from the waste plastics liquefaction process under the Japanese Containers
and Packaging Recycling Law. Presently, thermal degradation residue and hydrochloric acid are being produced as by-products
in addition to the hydrocarbon oil. As a result, the SPR plastics liquefaction plant has achieved a high reclamation rate
of 96%, and 93% of the recycled products have been reused in Hokkaido, where SPR is located. The technical problems caused
by corrosion and clogging have been solved.
Chemical Feedstock Recycling & Other Innovative Recycling Techniques 6 相似文献
67.
制定南京市机动车污染防治地方性法规的思考 总被引:2,自引:0,他引:2
周海茵 《环境监测管理与技术》2009,21(2):8-11
简述了南京市机动车污染现状,分析了目前机动车污染防治规章在实施过程中存在的问题。借鉴国内其他城市机动车污染防治相关法规的规定及其成功经验,提出应建立部门联动机制,加强尾气执法监管,强化定期检测和监督抽测,确保达标排放,启动环保标志管理,积极推进区域限行,完善管理手段,逐步淘汰高污染车辆,建立信息平台,加强对在用车维修治理工作的监管。 相似文献
68.
This paper describes one example of how the UK National Air Quality Strategy (NAQS) is implemented in a local urban environment. The paper reviews the beginning of this process, by examining the review and assessment procedures of the NAQS in the London Borough of Barnet. By the application of available UK tools of local air quality management (LAQM), the process began through analysis of the levels of local emissions and progressed onto modelling of current and future air quality. A map showing combined emission hotspot areas for the Borough indicated and higher emission rates occur in the south of the Borough and along the major transport corridors, as road sources dominate emissions. Dispersion modelling studies were also conducted for this purpose, using the screening models GRAM, PGRAM and ADMS Urban for an in-depth assessment. These analyses found that some local point sources and the majority of Borough roads with over 20,000 vehicles per day produced exceedances of the future objectives for air quality for some pollutants.Recommendations for the progression of LAQM in the Borough are made and include the update and expansion of the emissions information held for use in future modelling studies. The paper demonstrates the experience of implementing the Strategy, using the tools and procedures available for this purpose, in a local urban environment that is similar to many in the UK. 相似文献
69.
Phyt'Eaux Cités: application and validation of a programme to reduce surface water contamination with urban pesticides 总被引:1,自引:0,他引:1
This paper presents first results of Phyt’Eaux Cités, a program put in place by the local water supply agency, the SEDIF (Syndicat des Eaux d’Ile-de-France), in collaboration with 73 local authorities, private societies and institutional offices (365 km2). The challenges included: measurement of the previous surface water contamination, control of urban pesticide applications, prevention of pesticide hazard on users and finally a overall reduction of surface water contamination. An inquiry on urban total pesticide amount was coupled with a surface water bi-weekly monitoring to establish the impact of more than 200 molecules upon the Orge River. For 2007, at least 4400 kg and 92 type of pesticides (essentially herbicides) were quantified for all urban users in the Phyt’Eaux Cités perimeter. At the outlet of the Orge River (bi-weekly sampling in 2007), 11 molecules were always detected above 0.1 μg L−1. They displayed the mainly urban origin of pesticide surface water contamination. Amitrole, AMPA (Aminomethyl Phosphonic Acid), demethyldiuron, diuron, glyphosate and atrazine were quantified with a 100% of frequency in 2007 and 2008 at the Orge River outlet. During the year, peaks of contamination were also registered for MCCP, 2,4 MCPA, 2,4 D, triclopyr, dichlorprop, diflufènican, active substances used in large amount in the urban area. However, some other urban molecules, such as isoxaben or flazasulfuron, were detected with low frequency. During late spring and summer, contamination patterns and load were dominated by glyphosate, amitrole and diuron, essentially applied by cities and urban users. Both isoproturon and chlortoluron were quantified during autumn and winter months according to upstream agricultural practices. In conclusion, 3 years after the beginning of this programme, the cities reduced the use of 68% of the total pesticide amount. An improvement on surface water quality was found from 2008 and during 2009 for all pesticides. In particular, glyphosate showed a decrease of the load above 60% in 2008, partly related to the Phyt’Eaux Cités action. 相似文献
70.
Examining Hazard Mitigation Within the Context of Public Goods 总被引:1,自引:0,他引:1
Reddy SD 《Environmental management》2000,25(2):129-141
/ This paper presents a case study of an American barrier island devastated by a hurricane to show how it is addressing the free-riding problem and protecting its public goods, thereby contributing to hazard mitigation. It examines hazard mitigation and the free-riding problem within the public goods framework. Free-riding is a term used in the public choice theory and common pool resource literature. It is a term used for describing the actions of rational individuals who freely exploit a collective or public good at the expense of others. Free-riding is a major problem faced by public goods. The problem very frequently occurs in the context of hazard mitigation and coastal resource management. Very little is known about the factors that contribute to the promotion of hazard mitigation. This paper identifies some of the important factors that help local institutions provide and sustain hazard mitigation measures. Theoretical and practical implications for hazards research and disaster management policy are presented. 相似文献