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371.
Sperm competition theory predicts that males should tailor their investment in ejaculates according to the number of rival males competing to fertilize a female’s eggs. Research spanning several taxa supports this prediction by showing that males are often sensitive to the level of sperm competition and adjust their investment in sperm numbers accordingly. More recent work has revealed that males may also tailor the quality of sperm according to the number of males competing for fertilization. Here I test for both effects in guppies (Poecilia reticulata) in an experiment that simultaneously evaluates the risk and intensity models of sperm competition. The experiment determined whether male guppies adjust the number (stripped ejaculate size) and quality (sperm velocity and viability) of sperm that are primed over a 3-day period according to experimental changes in the perceived level of sperm competition. A total of 136 focal males were initially stripped of all retrievable sperm and assayed for these sperm traits before being allocated at random to one of four treatments simulating different levels of sperm competition risk and intensity. During the 3-day treatment phase, focal males had visual and olfactory access to a sexually receptive (initially virgin) female maintained with different numbers of stimulus males to simulate variation in the risk and intensity of sperm competition. Following this, males were assayed again for the sperm traits. Contrary to predictions, there was no significant change in any of the measured variables among treatments, although qualitatively the patterns for sperm velocity and viability did conform to expectation. The lack of any trend for the number of sperm primed was unequivocal and future work examining the effects of sperm competition on sperm production should focus on whether males differentially allocate sperm numbers among matings that differ in the level of sperm competition.  相似文献   
372.
乾隆三年宁夏大地震救济刍议   总被引:1,自引:0,他引:1  
清乾隆三年宁夏府大地震,造成了严重的社会危机.震后地方政府首先作出反应,一边开展自救,一边向中央政府汇报.中央政府在接到灾情汇报后,组织了一系列赈济.文章从政府层面面对地震灾害后出现的诸问题角度,探讨清代中央政府与地方政府应对地震灾害的措施.指出正是中央政府与地方政府紧密的配合,才避免了地震灾情的恶化.  相似文献   
373.
This article examines the opportunities for fostering sustainable development through public sector sourcing from small- and medium-sized enterprises (SMEs). Buying from small businesses can make such contributions in a variety of forms, ranging from a contribution to local economic development through providing innovative green products and services, particularly in the food sector, to helping the public sector organisation to better align its operations with its community. Sourcing from small businesses also has implications for the governance of sourcing processes and can benefit from a partnership approach. Barriers to public sector sourcing from small businesses are discussed and suggestions made on how these can be overcome.  相似文献   
374.
Yearlong hibernation in a marsupial mammal   总被引:4,自引:3,他引:1  
Many mammals hibernate each year for about 6 months in autumn and winter and reproduce during spring and summer when they are generally not in torpor. I tested the hypothesis that the marsupial pygmy-possum (Cercartetus nanus), an opportunistic nonseasonal hibernator with a capacity for substantial fattening, would continue to hibernate well beyond winter. I also quantified how long they were able to hibernate without access to food before their body fat stores were depleted. Pygmy-possums exhibited a prolonged hibernation season lasting on average for 310 days. The longest hibernation season in one individual lasted for 367 days. For much of this time, despite periodic arousals after torpor bouts of ∼12.5 days, energy expenditure was reduced to only ∼2.5% of that predicted for active individuals. These observations represent the first report on body-fat-fuelled hibernation of up to an entire year and provide new evidence that prolonged hibernation is not restricted to placental mammals living in the cold.  相似文献   
375.
梳理和总结新中国初期我国应对海洋灾害的实践,有助于我们了解海洋灾害的应对措施并为当今提供借鉴。通过对我国海洋灾害史料的分析和总结,得知从新中国成立至改革开放前这一时期内,"防重于救"是我国应对海洋灾害的的主要指导思想,在海洋灾害预测预警、建设防护性工程、群众自救和政府辅以必要救济等方面发挥了重要作用,并为之后我国应对海洋灾害打下了一定基础。  相似文献   
376.
农村非政府应急组织是以共同应对农村突发事件为纽带自愿结成的互助性合作联盟,成员间的利益分配关系是组织生存与发展的重要基础。而Shapley值法正是解决多人合作利益分配问题的一种简便易行的数学方法。基于Shapley值法构建农村非政府应急组织利益分配激励模型能较好地促进其成员间的信任、合作与共享信息,使其收益透明化,有助于全面提升应急服务效益和充分发挥应急服务功能。首先,介绍了基于Shapley值法构建农村非政府应急组织激励模型的研究现状,然后初步探索了构建步骤及其实施建议,以进一步促进农村非政府应急组织的稳定运行与健康发展。  相似文献   
377.
This paper explores how social networks and bonds within and across organisations shape disaster operations and strategies. Local government disaster training exercises serve as a window through which to view these relations, and ‘social capital’ is used as an analytic for making sense of the human relations at the core of disaster management operations. These elements help to expose and substantiate the often intangible relations that compose the culture that exists, and that is shaped by preparations for disasters. The study reveals how this social capital has been generated through personal interactions, which are shared among disaster managers across different organisations and across ‘levels’ within those organisations. Recognition of these ‘group resources’ has significant implications for disaster management in which conducive social relations have become paramount. The paper concludes that socio‐cultural relations, as well as a people‐centred approach to preparations, appear to be effective means of readying for, and ultimately responding to, disasters.  相似文献   
378.
2020年是决胜脱贫攻坚战的关键之年,近20多年来,生态环境部门主动发挥行业特色,开展了大量坚实有效的行业扶贫工作,科学客观地评价生态环境部门的扶贫绩效,对于生态环境部门进一步精准施策、融入并推动实现乡村振兴具有重要意义. 本文基于实地调研、专家咨询和统计数据,建立了包括生态资源保护、环境质量改善、促进特色产业发展、社会公共服务提升以及抵御风险等4类26项指标在内的生态环境行业扶贫绩效评估指标体系;采用熵值法确定指标权重,结合多元统计分析方法,以承德市围场满族蒙古族自治县(简称"围场县")为例,对生态环境部门扶贫绩效进行了量化评估. 结果表明:①2006-2018年,承德市围场县扶贫绩效呈逐年上升的趋势,增长了68.3%,成效十分显著. ②生态环境行业扶贫在围场县的扶贫绩效主要体现在促进特色产业发展、生态资源保护以及环境质量改善等3个方面,占总绩效的81.1%. ③生态环境行业扶贫对促进生态环境质量改善与地方经济协同发展的促进作用较为显著. 在环境质量改善绩效指标上升47.1%的同时,促进特色产业发展和抵御风险能力绩效指标分别上升了90.5%和83.3%. 研究显示,生态环境行业定点扶贫对提升贫困地区持续"造血"能力具有显著促进作用,生态环境部门要主动作为,积极融入乡村振兴的全过程,进一步提升措施的针对性,在帮助贫困地区保住优质生态资源的同时,充分挖掘生态资源的经济优势,推动贫困地区巩固好脱贫成效,实现乡村振兴.   相似文献   
379.
针对现阶段政府监管主导下的职业健康治理模式存在的不足,从社会组织的角色定位、社会组织参与下的职业健康治理体系构成与运行机制等方面提出建议,并以目前多个地方现行的社会组织参与下的职业健康治理实践工作为例,对相关治理模式进行分析与总结,本文所提出的社会组织参与下的治理模式可以为各级政府和企业进一步提高相关职业健康治理水平提供参考和借鉴。  相似文献   
380.
现阶段,资源过度消耗与环境恶化成为中国经济与社会可持续发展的障碍。虽然现有研究从多方面探究了环境污染的治理机制,但对政府推动型城镇化这一重要的宏观政策的关注不足。本文以中国工业企业为研究样本,利用撤县设区改革的准自然实验构建双重差分模型,考察政府推动型城镇化对企业污染排放的影响。实证结果显示,撤县设区改革显著地减少了原县辖区内企业的污染排放量,即政府推动型城镇化对企业污染排放具有“治理效应”。异质性分析发现,撤县设区改革对企业污染排放的“治理效应”来源于主动推动型撤县设区而非被动实施型撤县设区;相比于在非重污染行业的企业以及隶属于县级以上的企业中,撤县设区改革对企业污染排放的“治理效应”在重污染行业的企业以及隶属于县级以下的企业中更强。影响机制分析发现,撤县设区改革后,原县级政府的财政收入显著下降、基础建设性财政支出显著减少而民生性财政支出显著增加,说明撤县设区后,原县级政府财政收入的经济激励弱化,财政支出目标亦从基础设施建设转变为提供公共服务,从而有助于治理企业污染排放问题。  相似文献   
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