加氢裂化REAC系统双相不锈钢管道焊缝铁素体含量的讨论

本文介绍了专利商对应用于加氢裂化REAC系统的双相不锈钢S32205焊接接头的要求,简要说明了双相不锈钢的焊接工艺评定;分析了填充金属化学成分、焊接线能量、焊接冷却速度对双相不锈钢焊缝铁素体含量的影响;分析了双相不锈钢焊缝铁素体含量达到专利商要求的能力,以及手工电弧焊焊缝铁素体含量达不到专利商35%~60%要求的原因是焊条化学成分设计的结果;分析了焊缝铁素体含量要求的合理性,介绍了AWS、API、NACE及国家行业标准对于双相不锈钢焊接接头铁素体含量的要求;介绍了现场的焊接工艺,以及使实际焊缝达到使用要求的方法.     

上海郊区小型沼气发展的前景与方向

文章介绍了上海郊区沼气开发利用的发展历程和现状,分析了上海沼气发展萎缩的原因,指出上海在节能减排的大形势、寻找合理的农村生活垃圾处理出路和解决小型禽畜养殖场的环境问题等压力下,对郊区的沼气发展产生了新的需求。而以小型养殖场为中心、吸纳农村有机生活垃圾的小型沼气系统则是上海郊区未来沼气发展的方向,也是新农村环境整治的可行途径。     

贸易开放、劳动力转移和就业

长久以来主流国际贸易模型中充分就业的假设使经济学界忽略了对贸易开放如何影响就业的分析,而哈里斯-托达罗模型则为此提供了一个可供扩展的框架.将哈里斯-托达罗模型扩展到存在贸易开放的情况后,本文发现如果一国的比较优势为制造品,贸易开放将会减少就业,这是因为制造品价格的提高会吸引更多的劳动力从农业向制造业转移,而制造业部门劳动力市场刚性的存在则阻碍了劳动需求的增加.为了研究我国改革开放以来贸易开放对就业的影响机制,并且考虑到就业的持续性,本文利用我国省际面板动态数据进行实证研究,并使用国有企业和政府部门劳动力占比度量我国劳动力市场刚性程度.实证研究结果发现当不考虑劳动市场刚性时,由于我国的比较优势是劳动密集型产品,贸易开放能增加就业;而当劳动力市场刚性较大时,劳动力转移过程反而促使贸易开放减少我国的就业,恰好验证了本文的理论分析结果.该文的政策含义则意味着政府应努力降低劳动力市场刚性以促使贸易开放增加就业.     

Impacts of the Rising Opportunity Cost of Farm Labor on Agricultural Land Use Structure: Theory and Empirical Evidences

Abstract

Nowadays the rising of opportunity cost of farm labor comes to the forefront of attention in China. In order to understand its impact on agricultural land-use structure, a theoretical framework of household economics is formulated drawn on Low’s model. Under the theoretical framework, the impact of the rising opportunity cost of on-farm on cropping structure is deduced in theory. And then, using statistic and survey data, taking mountain area of southern Ningxia as an example, the theoretical assumes are verified. The results show that the rise of opportunity cost of farm labor leads to less diversified cropping structure.     

Holistic well-being and sustainable organisations – A review and argumentative propositions

Abstract

This article discusses holistic well-being in a balanced work system theory framework. Holistic well-being is a combination of well-being in both work and non-work domains. Theories of balanced work systems and balanced organisations are retold in light of holistic well-being to show how different individuals in organisations can contribute to achieving desired outcomes at different process levels. Further, this article provides new insights and research challenges to the balanced organisation theory by including a sustainability aspect and by proposing a new concept of balanced value networks.     

城乡劳动力流动及其对农地利用影响研究评述

农业劳动力务农机会成本呈上升趋势,促使大量农业劳动力向城镇流动,成为当今中国社会的一个突出特征。劳动力城乡流动会影响农户的土地利用决策行为,继而影响土地利用变化过程。为理解这一过程对于农地利用变化的影响,文章首先综述了城乡劳动力流动理论研究的历史脉络,并总结了国内外劳动力流动对农地利用影响的研究进展。提出了尚需研究的若干学术问题,即在方法上需要建立劳动力流动-农户土地利用决策模型,重视农户尺度研究,注重区域差异。     

Two Major Relative Comparative Advantages of China in International Trade

Sustainable development requires enriching and developing the traditional international trade theory, especially integrating the environmental elements into the current analysis framework of relative comparative advantages. These relationships among labor, capital, and environmental resources are analyzed in this study, using the relative comparative advantages method. As indicated in the analysis, the ever-increasing international trading volume in China relies not only on the relative comparative advantage of labor but also on the environmental one; these are the two major advantages in China. However, the two advantages will experience serious challenge in the future along with a rising cost on labor and environmental pollution.     

RAPD markers suggest genotypic effects on forager specialization in a eusocial wasp

Genetic variability within insect societies may provide a mechanism for increasing behavioral diversity among workers, thereby augmenting colony efficiency or flexibility. In order to assess the possibility that division of labor has a genetic component in the eusocial wasp Polybia aequatorialis, I asked whether the genotypes of workers within colonies correlated with behavioral specialization. Workers specialized by foraging for one of the four materials (wood pulp, insect prey, nectar, or water) gathered by their colonies. I collected foragers on 2 days from each of three colonies and identified the material the foragers were carrying when collected. I produced random amplified polymorphic DNA (RAPD) markers from the genomic DNA of these foragers and estimated genotypic similarity of foragers based on sharing of variable RAPD marker bands. Contingency tests on 20 variable loci per colony showed statistically significant (P <0.05) biases in RAPD marker frequencies among forager types in the three colonies. Patterns of association of RAPD marker bands with specializations were constant in two colonies, but changed between collection days in one colony. RAPD marker biases suggest that division of labor among workers includes a genetic component in P. aequatorialis. Colony-level selection on variation in division of labor is a possible factor favoring the evolutionary maintenance of high genotypic variability (low relatedness) in epiponine wasp colonies and in other eusocial insects. Received: 18 July 1995/Accepted after revision: 1 October 1995     

The dynamics of strike votes: Perceived justice during collective bargaining

Why do workers decide to go on strike or change their mind during a strike? This field study aims to determine to what extent employees' perceptions of justice formed during the collective bargaining process influence their strike vote. Data were collected from a North American university faculty that went on strike 21 months after the expiration of its collective agreement. The results show that perceived justice about collective bargaining is a determinant of the strike vote. The role played by the employer and the union as a source of (in)justice and the importance of the four types of justice perceptions (procedural, distributive, interpersonal, and informational) vary depending on the context of ballots (initiate, continue, or end the strike). This suggests that the reduction of uncertainty leads to the activation of three different mechanisms: judgmental heuristics (salience), social comparison, and cognitive dissonance. The results also suggest that employees attempt to be as rational as possible when they decide to go on strike. Nevertheless, the decision to join strikers and to continue the strike is partly based on an emotional process: employees use the strike to punish the employer. Copyright © 2012 John Wiley & Sons, Ltd.     

Evolution of extreme polyandry in the honeybee Apis mellifera L.

A number of hypotheses have been proposed to explain the evolution of multiple mating in the honeybee queen. In particular, the consequences of reduced intracolonial relatedness provide plausible explanations for multiple mating with up to ten drones, but fail to account for the much higher mating frequencies observed in nature. In this paper, we propose an alternative mechanism which builds on non-linear relationships between intracolonial frequencies in genotypic worker specialization and colony fitness. If genes for any worker specialization confer an advantage on colony fitness only when they are rare, this would require a stable mix of sperm from a few drones which contribute that trait, and many which do not. To ensure both specific, low within-colony proportions of “rare specialist” genes, and to reduce random variation of these proportions would require mating with high numbers of drones. The quantitative implementation shows that moderate to very high numbers of matings are required to exploit colony advantages from genotypic allocation of workers to rare tasks. Extreme polyandry thus could result from colony selection dependent on the intracolonial frequency of rare genetic specialists. Received: 30 January 1998 / Accepted after revision: 7 October 1998