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71.
三氯杀螨醇的雌激素效应及其机制的研究进展 总被引:5,自引:0,他引:5
三氯杀螨醇(dicofol,DCF)是现代农牧业生产中广泛使用的一种杀虫剂,许多实验证据表明它对动物和人体有雌激素效应,如导致美洲鳄(Alligator mississippiensis)发生雌性化现象、使美洲鹰(Falco sparverius)的卵壳变薄、引起小鼠子宫增重、促进人类乳癌细胞(MCF7)增殖等。有关它的作用机制研究目前主要集中在下丘肛-垂体-性腺轴中的激素受体上,本文对DCF的雌激素效应及其作用机制研究进展做了回顾。 相似文献
72.
Ecohealth is a process for identifying key environmental determinants causing mortality or morbidity and combating them by mobilizing multiple social sectors. Evolving out of the concept of environmental health, ecohealth provides a framework for long‐term sustainability. The health outcomes anticipated by environmental interventions are part of a long‐term agenda and require fundamental groundwork for the growth of community‐driven development. Building long‐term sustainability requires that two key approaches be developed through ecohealth. The first is the strengthening of local community institutions, whether formal or informal. The second is building financial mechanisms that are more diversified and less reliant on a single donor. As a result, the ecohealth system provides an opportunity for foundations to empower communities, build cross‐cutting cooperation, and gain knowledge through projects. If people's environmental behaviour is to change and be sustained in the long term to produce desired health outcomes, this will require all members of society to be capable of functioning within the existing institutional infrastructure. This means that not only do formal institutions need to become more accessible but also that concepts relating to local informal institutions must be incorporated into ecohealth projects. It is imperative that we identify and understand relevant local institutions and how they can be transformed so that new environmental forms of behaviour can be sustained and result in positive health outcomes. The intersection of environmental and health concerns provides an ideal area in which the gap between government and civil society can be bridged — not only providing solutions to ecohealth concerns, but building government capacity in general and making these positive changes sustainable in the long term. This article is a case study, based on several United Nations Foundation grants. It outlines the significance of traditional community organizations, the breadth of their long‐term relations with communities, their resources, and the adoption of sustained forms of behaviour. In addition, the article highlights the role that international foundations can play in creating innovative financing mechanisms through community‐based foundations. 相似文献
73.
结合知识产权现有的实践活动,结合中国的行政程序,提出了知识产权审查机制的基本框架,实现了知识产权审议的基本程序和开展重大经济活动的一般程序的有机融合。在该基础上,对重大经济活动知识产权审查机制的管理模式进行了概念设计,为构建和完善知识产权审查机制提供了有益的参考。 相似文献
74.
ABSTRACT: Literatures on price‐based urban water conservation and on market‐based mechanisms to manage natural resources suggest that market‐based management of urban/suburban water use may be feasible. A market‐based proposal that emerged from a water shortage on California's Monterey Peninsula is presented. In the proposal, conservation incentives arise both from an ability among end‐users of water to reduce consumption and sell use‐rights to water, and from a penalty price for consumption in excess of one's use rights. The amount of water associated with use rights is capped and varies according to hydrological, meteorological, ecological, and other criteria. Requirements for further study of the proposal are listed, and the role that similar market‐based mechanisms could play in urban water management is discussed. 相似文献
75.
76.
Katrin Brauch Keith Hodges Antje Engelhardt Kerstin Fuhrmann Eric Shaw Michael Heistermann 《Behavioral ecology and sociobiology》2008,62(9):1453-1466
In a wide variety of species, male reproductive success is determined by contest for access to females. Among multi-male primate
groups, however, factors in addition to male competitive ability may also influence paternity outcome, although their exact
nature and force is still largely unclear. Here, we have investigated in a group of free-ranging Barbary macaques whether
paternity is determined on the pre- or postcopulatory level and how male competitive ability and female direct mate choice
during the female fertile phase are related to male reproductive success. Behavioural observations were combined with faecal
hormone analysis for timing of the fertile phase (13 cycles, 8 females) and genetic paternity analysis (n = 12). During the fertile phase, complete monopolisation of females did not occur. Females were consorted for only 49% of
observation time, and all females had ejaculatory copulations with several males. Thus, in all cases, paternity was determined
on the postcopulatory level. More than 80% of infants were sired by high-ranking males, and this reproductive skew was related
to both, male competitive ability and female direct mate choice as high-ranking males spent more time in consort with females
than low-ranking males, and females solicited copulations mainly from dominant males. As most ejaculatory copulations were
female-initiated, female direct mate choice appeared to have the highest impact on male reproductive success. However, female
preference was not directly translated into paternity, as fathers were not preferred over non-fathers in terms of solicitation,
consortship and mating behaviour. Collectively, our data show that in the Barbary macaque, both sexes significantly influence
male mating success, but that sperm of several males generally compete within the female reproductive tract and that therefore
paternity is determined by mechanisms operating at the postcopulatory level. 相似文献
77.
四氧化三铁/聚乙烯亚胺纳米颗粒的制备及除磷性能的研究 总被引:1,自引:0,他引:1
采用化学共沉淀法,以聚乙烯亚胺(PEI)为改性剂,制备了聚乙烯亚胺改性的纳米四氧化三铁复合材料(Fe3O4/PEI).Zeta电位、透射电镜和FTIR表征结果显示,PEI修饰提高了纳米Fe3O4在水中的分散性和稳定性,同时也增强了其表面正电荷,从而提高了Fe3O4对水中磷酸根的去除能力.在磷酸根初始浓度为50 mg·L~(-1),Fe3O4/PEI投加量为200 mg,p H=3,温度为25℃的条件下,Fe3O4/PEI对100 m L磷酸根的吸附去除率达到91%.吸附过程在3 h内达到平衡.吸附等温数据表明,该吸附过程符合Langmuir吸附等温方程,可决系数R2达到0.99,最大吸附量为29.88 mg·L~(-1).Fe3O4/PEI复合材料重复利用性好,在第5次吸附-解析后还能保持对磷酸根75%以上的吸附去除率.磷的解析效率随着p H增加而增加,在p H=13时,解析效率达到65%. 相似文献
78.
79.
Incentive-based mechanisms are regarded as efficient instruments to reconcile conservation and development. This win-win objective has been difficult to accomplish; cross-compliance has, therefore, been suggested as a mechanism to ensure sustainability. Cross-compliance, which requires producers to conform to production regulations and environmental standards to qualify for direct payments, has been a popular instrument in the Common Agricultural Policy (CAP) reform. Since 1990, cross-compliance has been the main characteristic of policy design in Sami reindeer husbandry in Finnmark, Norway. All direct transfers to the Sami pastoralists have been connected to harvesting demands to decrease the number of reindeer and to conserve pastures. The content of these incentive-based mechanisms are decided through negotiated agreements with the Sami Reindeer Herders' Association of Norway (NRL), and the regulation of reindeer numbers and access to pastures are delegated to co-management boards. Despite the participation of the Sami pastoralists in shaping these policies, win-win objectives have not been achieved. Although the cross-compliance program could have been improved by payment for graded results, the lack of regulations by the administration or co-management boards is more likely to be the cause of failure to reach sustainability. Despite the long-term failures of the cross-compliance program, policies have been slow to change. We might attribute this delay to the NRL's strong position in the negotiated agreements. In general, we argue that the success of the cross-compliance program depends on a well-functioning governance system that can implement regulations and sanctions if incentives do not work as intended. 相似文献
80.