公共财政投入与农村公共物品供给

农村公共物品的供给对新农村建设、消除＂二元结构＂和城乡统筹发展具有重大意义.长期以来,＂二元＂经济社会结构导致城乡分割,公共财政未能覆盖农村,造成我国农村公共物品供给总量不足,供给结构不合理,严重制约了社会发展.文章对农村公共物品的界定及特征,目前我国农村公共物品供给和公共财政投入的现状及存在的问题进行了分析,并提出了公共财政投入农村公共物品的对策建议.     

Running with the Red Queen: host-parasite coevolution selects for biparental sex

Most organisms reproduce through outcrossing, even though it comes with substantial costs. The Red Queen hypothesis proposes that selection from coevolving pathogens facilitates the persistence of outcrossing despite these costs. We used experimental coevolution to test the Red Queen hypothesis and found that coevolution with a bacterial pathogen (Serratia marcescens) resulted in significantly more outcrossing in mixed mating experimental populations of the nematode Caenorhabditis elegans. Furthermore, we found that coevolution with the pathogen rapidly drove obligately selfing populations to extinction, whereas outcrossing populations persisted through reciprocal coevolution. Thus, consistent with the Red Queen hypothesis, coevolving pathogens can select for biparental sex.     

农村公共品贡献度的经验分析:以江苏省农业为例

通过对江苏农业增长的影响因素回归分析并进行测算,结果表明:公共品对农业产出及其总要素生产率具有重要的影响,特别是教育对农业增长存在显著正效应.测算结果表明,农业总要素生产率对农业产出的贡献与农业基本投入要素的贡献大体相当;在农业总要素生产率的增长贡献中,公共品的贡献率达到75%.因而,提高农村公共品的供给水平是实现工农业协调发展一条比较有效的途径.     

我国农村公共物品供给存在的问题原因及对策

农村公共物品的有效供给是保证农村稳定发展的重要条件和保障,也是建设社会主义新农村的应有之义。应加大对农村财政转移支付的力度,缩小地区间的差别,形成自下而上的供给决策机制。     

农村公共安全防治中府际协作的困境与破解路径

通过对府际协作理论和公共安全研究的综述,发现农村公共安全府际协作治理中存在风险源复杂、资源调配难、协作动力弱、效果不突出等问题,对此提出了基层政府在农村公共安全治理中府际协作的优化路径,应在确定基本原则的同时,设定协作治理目标,通过创建跨域治理协作机制,开创农村公共安全治理新局面。     

农村公共产品供给困境实例分析——以新型农村合作医疗为例

我国农村公共产品供给缺失、不足的现状积弊已久,应更多地予以其关注,加大供给投入和力度。鉴于医疗供给上的特殊性,及长期以来医疗供给存在的诸多弊端,本文以此为例,着重从空间布局和结构布局两个维度分析当前农村卫生服务体系建设的相关突出问题,并进行规避路径探析,俾使新型农村合作医疗的构建与完善能更贴近实际需求,能更快、更好地产生实效。     

不同收入视角下农户对农村公共品的需求偏好分析

本研究利用四川、河南、山西、陕西、贵州、宁夏6省1 146户农户微观数据,分析了不同收入水平农户对农村公共品的需求偏好,并采用二元Logistic模型,实证研究了农户对农村公共品的需求偏好与其影响因素之间的作用机理。研究表明,农户对农村公共品的整体需求意愿较为强烈,且农户的需求意愿随着收入水平的提高而提升;农户对不同类型公共品的需求偏好表现出一定的层次性或具有一定的差异性,即农户对医疗卫生保健的需求意愿最为强烈,其次依次是农村道路、农村社会保障、农村文化娱乐、农村基础教育;不同收入水平农户对不同类型公共品的需求偏好呈现出不同的特点;对于农户公共品需求偏好的影响因素而言,不同的因素对农户公共品需求偏好的影响方向和程度有所差异,但是对其产生共同关键影响的因素有村庄经济发展程度、受教育程度、政策支持、地方政府对中央政策的执行效果。     

Stick-slip as a mechanism for earthquakes

Stick-slip often accompanies frictional sliding in laboratory experi ments with geologic materials. Shallow focus earthquakes may represent stick slip during sliding along old or newly formed faults in the earth In such a situation, observed stress drops repre sent release of a small fraction of the stress supported by the rock surround ing the earthquake focus.     

不同育王方式对意大利蜜蜂王台接受率和蜂王质量的影响

以意大利蜜蜂为试材,分别在春季与秋季对单式移虫育王法、复式移虫育王法和免移虫育王法的王台接受率和蜂王质量进行比较。结果表明：免移虫育王法的王台接受率（72.62%）极显著地低于单式移虫育王法和复式移虫育王法,但蜂王质量优于单式移虫育王法和复式移虫育王法培育的蜂王;单式移虫育王法和复式移虫育王法在春季培育蜂王的质量高于秋季培育的蜂王,而免移虫育王法在春季和秋季培育的蜂王质量差异不显著。     

闽台旅游安全管理合作机制研究

认为旅游安全是旅游业的生命线,是区域旅游合作的重要基础和内容。分析了闽台旅游安全管理合作的背景与意义,比较了闽台旅游安全管理合作的环境。结合旅游安全保障体系和旅游安全管理体系,提出构建＂闽台旅游行业协会联盟＂等6个安全管理合作平台与建立＂闽台旅游安全制度交流＂等8个机制。     

高校汽车类应用型人才校企合作培养机制研究

校企合作是培养高技能应用型人才的重要途径。当前校企合作通常采用订单式、引厂入校、资源共享等合作模式,但多数合作简单、不深入,缺乏全面性、长效性和制度性。以河北农业大学和长城汽车股份有限公司合作成立长城汽车学院为例,分析了校企共建合作模式及其特点,阐述了企业、学生在校企合作中缺乏积极性的根源,指出了均衡利益、转变观念、构建评价机制、提供社会保障,是校企合作汽车类应用型人才培养的长效机制。     

Organelle alteration as a mechanism for maternal inheritance

An ultrastructural study of pollen-derived plants and normal microspore development indicates that chloroplasts and mitochondria are physically altered during microsporogenesis. These changes appear to debilitate the organelle so that only chloroplasts and mitochondria of the female parent are contributed to the offspring.     

Anticrack nucleation as triggering mechanism for snow slab avalanches

Snow slab avalanches are believed to begin by the gravity-driven shear failure of weak layers in stratified snow. The critical crack length for shear crack propagation along such layers should increase without bound as the slope decreases. However, recent experiments show that the critical length of artificially introduced cracks remains constant or, if anything, slightly decreases with decreasing slope. This surprising observation can be understood in terms of volumetric collapse of the weak layer during failure, resulting in the formation and propagation of mixed-mode anticracks, which are driven simultaneously by slope-parallel and slope-normal components of gravity. Such fractures may propagate even if crack-face friction impedes downhill sliding of the snowpack, indicating a scenario in which two separate conditions have to be met for slab avalanche release.     

True polar wander as a mechanism for second-order sea-level variations

Long-term wander of the rotation pole can be a significant contributor to second-order (time scales of approximately 100 million years) sea-level variations. Numerical predictions based on realistic viscoelastic Earth models and paleomagnetically constrained polar motion yield global-scale, differential sea-level trends that can be as large as approximately 200 meters. From the results presented here, it is argued that the well-documented, second-order, Cretaceous-Tertiary sea-level cycle should be reinterpreted as some combination of a eustatic and a regionally varying rotational signal.     

平潭综合实验区闽台旅游合作机制构建与路径发展思考

闽台旅游合作已成为福建区域旅游发展的显著特征和必然趋势,也是平潭综合实验区探索两岸区域合作的重要突破口。从分析平潭综合实验区闽台旅游合作背景入手,明确了实验区设立的政策优势、旅游发展优势及愿景等各项背景,从目标约束、组织协调、技术保障等方面构建实验区闽台旅游合作的“三维”机制,分析指出实验区闽台旅游合作的路径发展取向,即打造“海峡旅游”品牌产品体系、提升旅游企业竞争力、推进旅游人才无障碍流动,最终将实验区建设成为世界级旅游休闲目的地。     

公共图书馆"三农"服务模式探讨

公共图书馆应积极参与“三农”服务。笔者认为，以政府统筹为依据，通过知识扶贫和文化扶贫，采取送书下乡、实行“分馆制”、撰写提供二三次文献和举办多种活动的方式，在农村的社会发展中发挥积极作用，这是公共图书馆进行“三农”服务的有效模式。     

Assortative mating as a mechanism for rapid evolution of a migratory divide

There have been numerous recent observations of changes in the behavior and dynamics of migratory bird populations, but the plasticity of the migratory trait and our inability to track small animals over large distances have hindered investigation of the mechanisms behind migratory change. We used habitat-specific stable isotope signatures to show that recently evolved allopatric wintering populations of European blackcaps Sylvia atricapilla pair assortatively on their sympatric breeding grounds. Birds wintering further north also produce larger clutches and fledge more young. These findings describe an important process in the evolution of migratory divides, new migration routes, and wintering quarters. Temporal segregation of breeding is a way in which subpopulations of vertebrates may become isolated in sympatry.     

农业科技合作共建长效机制与农科专业实践教学结合的探索与实践

为了探讨农业科技合作共建与农科专业实践教学相结合的模式,进行校县农业科技合作共建长效机制建设与农科大学生实习实训基地建设相结合的探索与实践,系统总结探讨了两者的关系和建设的必要性、主要任务、创建途径、管理模式、双方义务、实习实训形式、保障措施及实践效果,为农科专业开展学生实习实训工作和建立农业科技合作共建长效机制提供参考。     

Oxygen tension as a control mechanism in pollen tube rupture

The decrease in stylar pO(2) encountered by pollen as it approaches the ovary can induce bursting of pollen tube tips. Anaerobic conditions induced a high percentage of tube tip bursting in most pollen germinated in vitro. Changes in tube tip metabolism with decreased oxygen probably sets up cell wall stress resulting in pollen tube rupture.