基于投影寻踪方法的粮食主产区农民用水合作组织绩效研究——基于湖北、湖南、黑龙江3省的调查

[目的]农民用水合作组织是我国灌溉管理制度改革的产物,农民用水合作组织的建立改进了农村水利管理的方式,提高了灌溉管理过程中水资源的利用率。[方法]通过构建粮食主产区农民用水合作组织绩效评价指标体系,建立基于实数编码加速遗传算法的投影寻踪分类模型,对湖北、湖南、黑龙江等3省61家农民用水合作组织的绩效进行了实证分析。[结果]粮食主产区农民用水合作组织绩效水平总体较好,在所调查的61家农民用水合作组织中,27.1%的农民用水合作组织绩效为优秀,28.8%绩效良好,13.6%绩效一般,30.5%绩效较差。[结论]总体上来看,湖南、湖北等2省农民用水合作组织的绩效高于黑龙江。是否有产权、农户参与率、是否民主决策、培训次数、农户满意度、单位面积灌水量和水费收取率等指标对农民用水合作组织绩效影响最大。因此,政府适当放权,选取恰当的扶持方式,提升农户的认识,推广好的农民用水合作组织发展模式是提高农民用水合作组织绩效的有效途径。     

Gains from horizontal collaboration among ski areas

Ski areas are known to expand by linking their lifts to neighbouring systems. Based on data from approximately 250 winter sport destinations in Austria, pooled over the years 1998–2014, this study explores the effects of such horizontal collaboration on the number of overnights stays in the area. A difference-in-differences (DID) approach combined with propensity score matching shows that new lift-linkages or expansions lead to a consolidation in the number of overnight stays at a level 12 per cent higher than before the introduction of the lift-link. However, there is a certain degree of heterogeneity in the causal effects. Satellite ski areas, remote villages and those who combine lift-linking with new connecting slopes benefit the most. More recent lift-linkages seem to lead to smaller gains than those established in the early years.     

Milk sales and dietary diversity among the Maasai

In Maasai culture, responsibilities are traditionally divided between genders. Men are in charge of grazing and managing the livestock herds. Women take care of the family, administer food supplies, and are responsible for milking. For them, balancing home consumption of milk (for the family and for the calves), milk sale, and food purchase is a major task. In this article, we first investigate how different milk sales groups vary regarding the use of different food items and the respective quantities consumed by the enkaji, i.e., a Maasai subhousehold. Then, we address the commercialization decision and assess the effect of milk sales on the enkaji's food item use and food consumption. Using the data of Maasai enkajijik in the milk catchment area of a milk collection center in Ngerengere, Tanzania, we estimate the effects by employing propensity score matching procedures. Our findings suggest that milk sellers, especially those selling to the milk collection center, have a more diverse diet. In terms of per person consumption, the groups are markedly similar. Therefore, we conclude that income generated by milk sales is invested in diet diversification rather than in increasing the quantity of food consumed, hence the enkajijik appear not to make use of caloric terms of trade.     

The effect of vaccination on children's physical and cognitive development in the Philippines

We use data from the Cebu Longitudinal Health and Nutrition Survey (CLHNS) in the Philippines to link vaccination in the first 2 years of life with later physical and cognitive development in children. We use propensity score matching to estimate the causal effect of vaccination on child development. We find no effect of vaccination on later height or weight, but full childhood vaccination for measles, polio, Tuberculosis (TB), Diphtheria, Pertussis and Tetanus (DPT) significantly increases cognitive test scores relative to matched children who received no vaccinations. The size of the effect is large, raising test scores, on average, by about half an SD.     

CAD中图层图块在机械图样中的应用

以法兰盘零件图为例,描述了图层、图块的功能,同时描述了图层设置方法,图块设置方法。探讨了绘制零件图时图层、图块应用方法与技巧。     

品牌与善因的匹配对善因营销的影响研究

通过文献回顾分析了企业与善因的匹配对善因营销效果的影响,结果发现,这种匹配对善因营销效果的影响不仅与消费者感知的匹配程度有关,同时还取决于消费者感知到的匹配类型(形象匹配与功能性匹配),以及许多调节变量(产品类型、购买情境、消费者对企业和善因的涉入及熟悉程度等)的影响。进而总结了目前研究的空白和不足,为未来的研究提出了建议。     

Flexibility at the Margin and Labor Market Volatility in OECD Countries*

We study the business‐cycle behavior of segmented labor markets with flexibility at the margin (e.g., just affecting fixed‐term contracts). We present a matching model with temporary and permanent jobs (i) where there is a gap in the firing costs associated with these types of jobs and (ii) where there are restrictions in the creation and duration of fixed‐term contracts. We show that a labor market with ``flexibility at the margin'' increases the unemployment volatility with respect to one that is fully regulated. This analysis yields new insights into the interpretation of the recent volatility changes witnessed in the OECD area.     

防治玻璃幕墙渗水浅谈

玻璃幕墙渗水原因非常复杂,涉及到设计、材料使用、施工和管理等各个方面。现对其进行简要分析。     

矿量分级制式观念有待创新

始自1909-1910年通行各国的多种矿量分级制式,在原则上是都以所谓地质信息的可靠性为标志。本文所倡议的矿量分级制式,将以总开发效益的可靠性为标志另行构筑,它能使矿块"级别-吨位-品位"指标的内在联系从幕后走到前台,使勘查者的各级矿量与开采者的三级矿量贯通一气。"级差品位指标制"在国内运行四十多年的成效,就是在块段吨位足够大的前提下尊重"级别-品位"依存关系的例证。