The Returns to Migration: The Influence of Education and Migration Type

We show the impact of migration type on real wages over time. We create a migration and earnings history from the National Longitudinal Survey of Youth over the period 1979–2002. We estimate the effects of primary, onward, and two types of return migration on real wages using a panel data model with individual, location, and time fixed effects. Panel data are well suited for the study of the returns to U.S. internal migration because the influence of migration on wages has been found to occur years after the event. We differentiate return migration into two types: return to a location with ties that form a geographical anchor (“home”) and return to a prior place of work. We find that real wage growth varies by migration type. Education attainment is a significant factor in real wage growth. Our results show that onward migration is an important channel by which the monetary rewards to a college education are manifested.     

棉花主茎叶与根系硝酸还原酶活性分布对播期和密度的响应

【目的】本研究旨在探讨大田轻简化栽培条件下棉花氮代谢随播期和密度的变化规律。【方法】选用华棉3109(G.hirsutum L.)于2014年在华中农业大学试验农场,采用裂区设计:播期为主区(S1,5月30日;S2,6月14日),密度为副区(D1,7.5株·m-2;D2,9.0株·m-2;D3,10.5株·m-2),研究了硝酸还原酶(Nitrate reductase,NR)活性在主茎叶位和根系的分布特点。【结果】1)不同播期和密度对叶片和根系NR活性平均值有显著影响。推迟播期对现蕾期棉花叶片与根系平均NR活性无显著影响,增加密度可降低叶片平均NR活性,但对根系平均NR活性无显著影响;推迟播期,显著降低初花期和盛花期棉花叶片NR活性平均值,但晚播对根系NR活性平均值的影响由侧根NR决定,增加密度,叶片和根系平均NR活性呈先升高后降低变化趋势,表明见花施肥后,晚播抑制了棉花地上部叶片氮代谢强度,而增强了地下部根系氮代谢强度;适度增加密度可显著增强棉花地上部叶片和地下部根系氮代谢强度。2)现蕾期叶片NR活性平均值初花期盛花期,根系NR活性平均值大体呈先升高后降低变化趋势。3)主茎叶位NR活性在3个时期均由上而下显著降低,以第1叶至第3叶波动较大,第4叶以下叶片间无显著差异,表明叶片NR活性与叶龄有关,幼叶氮代谢强度高于成熟叶片,成熟叶片之间氮代谢强度保持相对稳定。【结论】长江流域棉区(主要指湖北植棉区)棉花播种不应晚于6月14日,种植密度以9.0株·m-2最佳。     

城镇化进程中农民工创业意愿及其影响因素研究——基于甘肃省农民工调查数据的实证分析

为了研究农民工创业意愿的相关影响因素,对甘肃省289位农民工进行了调查,并运用二元Logistic模型实证分析了影响农民工创业意愿的因素。结果表明：从影响因素来看,年龄小、已婚、受教育程度越高、有创业经历、能得到家人支持且社交广泛的农民工创业意愿越强烈,而务工月收入、家庭人均纯收入越高、偏好冒险的农民工不倾向于创业。同时调查发现创业资金匮乏、没有一技之长、文化程度不高是农民工创业的最大障碍,担心创业失败是农民工创业的心理屏障。因此政府要加大创业资金扶持及政策宣传,加强农民工职业技能培训和创业培训,确保农民工能多渠道获取创业信息,引导农民工高效创业。     

Migrant labour and the politics of scale: gendering the Philippine state

The purpose of this paper is to situate the study of international labour migration, and especially the policies of labour export, within a gendered geopolitical framework. In so doing I open avenues of inquiry into the complexities of political ideologies that guide state apparatuses. Specifically, I examine how the Philippine state negotiates and operates within contradictory capitalist spaces through discourses of scale. Spatial scales are politically and socially constructed to legitimise power relations and to justify particular policies and programmes. In its support of capital accumulation, the Philippine state tends to adopt a discourse of globalisation; when confronted with charges of migrant exploitation, the Philippine state couples a discourse of the global with a discourse of the body. This corporeal discourse attempts to deflect attention and criticism away from the state, thereby maintaining its political hegemony.     

Indicators of resistance of sunflower plant to basal stalk rot (Sclerotinia sclerotiorum): Symptomatological,biochemical, anatomical,and morphological characters of the host

Summary The object of this work was a study of the relationship between the field reactions of different sunflower genotypes to basal stalk rot (in terms of severe (dead plants) and incipient wilting, and lesion length) and some biochemical (phenol concentration), morphological (plant height, and stem and flower-bud diameters) and anatomical (xylem and cortical indexes) characters of the host. Plants from 8 inbred lines at closed flower-bud stage were artificially inoculated with mycelium at the base of the stem. The percentage of dead plants for each inbred line and the lesion length and wilting range for individual plants after 7 days were recorded.A positive and highly significant correlation coefficient between the percentage of dead plants and lesion length was found for the three years of the study (r=0.83; P<0.01). A highly significant association between lesion length and wilting range for individual plants was always found (P=0.00). Postinfectional phenol content exhibited a strong negative correlation with lesion length and the percentage of dead plants in all the experiments (P=0.05). Association between postinfectional phenol content and wilting range for individual plants was significant for all the years studied (P<0.05). No correlation between phenol levels in healthy plants of the different sunflower genotypes and their susceptibility was found. Morphological characters positively correlated with lesion length but only plant height exhibited significant values for the three years. Associations between wilting range and morphological characters for individual plants were significant for one of the two years analyzed (P<0.05). Xylem index showed a negative correlation with lesion length which was significant one of the two years studied.The lesion length measure seems to be a simple and direct method for resistance screening before the flowering period. Although strong relations with postinfectional phenol levels were found, their determinations would be too much time consuming and not completely reliable. The relationships between other characters measured and disease resistance would indicate that physiological mechanisms could be related to resistance.     

Network Structure,Knowledge Governance,and Firm Performance: Evidence from Innovation Networks and SMEs in the UK

It is increasingly understood that learning and thus innovation often occurs via highly interactive, iterative, network‐based processes. Simultaneously, economic development policy is increasingly focused on small and medium‐sized enterprises (SMEs) as a means of generating growth, creating a clear research issue in terms of the roles and interactions of government policy, universities, and other sources of knowledge, SMEs, and the creation and dissemination of innovation. This paper analyses the contribution of a range of actors in an SME innovation creation and dissemination framework, reviewing the role of various institutions therein, exploring the contribution of cross‐locality networks, and identifying the mechanisms required to operationalise such a framework. Bivariate and multivariate (regression) techniques are employed to investigate both innovation and growth outcomes in relation to these structures; data are derived from the survey responses of over 450 SMEs in the UK. Results are complex and dependent upon the nature of institutions involved, the type of knowledge sought, and the spatial level of the linkages in place but overall highlight the value of cross‐locality networks, network governance structures, and certain spillover effects from universities. In general, we find less support for the factors predicting SME growth outcomes than is the case for innovation. Finally, we outline an agenda for further research in the area.     

代际差异视角下农民工留城意愿的影响因素研究——基于全国9省的调研数据

20世纪90年代以来,农民工群体出现了老一代农民工和新生代农民工的分化,为了解新老一代农民工留城意愿的现状以及影响因素,笔者基于代际差异视野下研究农民工留城意愿问题,采用全国9省3358名农民工的样本数据,从个体特征、家庭特征、工作特征、政策因素和心理因素这5个方面分别探析老一代和新生代农民工留城意愿的影响因素。研究发现：新、老农民工留城意愿影响因素以及影响程度有所不同,其中,教育程度、住房满意度、就业类型、是否有新农合等因素对新生代农民工留城意愿有显著的促进作用,婚姻对其具有显著的抑制作用;性别、教育程度、老家房产情况、月收入、日均工作时间、是否有养老保险、生活满意度等因素对老一代农民工留城意愿具有显著的促进作用。因此,要提高农民工的留城意愿,一方面要加大教育培训力度,提升农民工的就业质量;另一方面要完善和健全社会保障系统,为农民工留城减少后顾之忧。     

覆盖栽培对烤烟叶绿素、酶活性及丙二醛含量的影响

研究了烤烟大田栽培期间,旺长期揭膜培土后垄上覆盖稻草与旺长期揭膜培土、全生育期覆盖地膜、全生育期覆盖稻草等4种垄体覆盖方式对烤烟叶片叶绿素含量、有关酶活性和丙二醛含量的影响。结果表明：旺长期揭膜培土后垄上覆盖稻草的处理较其他3种处理的叶绿素含量、硝酸还原酶（NR）活性和过氧化物酶（POD）活性略高,而丙二醛（MDA）含量略低;该农艺措施下,上述指标的变化态势与烤烟生长代谢的调控机理基本一致,在信阳乃至黄淮烟区都具有推广利用价值。     

5株纤维菌属菌株的分离、鉴定及产酶活性研究

旨在将贵州的玉米秸秆生物质资源通过微生物降解还田,应用到烤烟轮作生产上.以植烟土壤为材料,采用刚果红染色法以及CMCase活性测定进行菌株的筛选,通过失重法测定秸秆降解率.实验共获得44株分解纤维素菌株;初筛获得20株纤维素分解菌.选择D/d较大的5株菌株,通过拮抗实验共获得复合菌剂10株.5株高效纤维素分解菌初步鉴定...     

Labor Market Segmentation in Urumqi,Xinjiang: Exposing Labor Market Segments and Testing the Relationship between Migration and Segmentation

Labor market segmentation and migration are two phenomena that are dramatically reshaping the spatial, economic, and social relationships of many urban cities in both developed and developing countries. To this point, the bulk of Chinese literature falls within the context of area studies, without much effort to link Chinese migration and emerging labor market outcomes to larger global trends and discourse. This research attempts to link the body of internal Chinese migration and emerging labor markets to labor market segmentation theory, primarily developed by urban economists and sociologists. My findings provide evidence that applying labor market segmentation theory to examine emerging markets in China offers fruitful results that help to identify the new urban stratification that exists in China. I employ a set of quantitative methods using employee‐level field data that I collected in Urumqi in 2008 to identify distinct segments within Urumqi's labor market and argue that migration is a major driver of labor market segmentation. Cluster analysis shows Uyghur minorities and women are found to be overwhelmingly concentrated in the lower sector, composed mostly of “bad” jobs. Discriminant analysis reveals that migrant status and ethnicity are the most important variables that deepen the gap among the labor market segments. The social inequality created as a result of market segmentation can partially explain Uyghur discontent in the region and the July 2009 riots, one of the worst riots in Xinjiang's modern history.     

防御酶活性、木质素和总酚含量与 辣椒抗黄瓜花叶病毒的关系

（1中国农业大学农学与生物技术学院蔬菜系，北京 100094； 2山东省烟台农业学校，烟台 264002）     

Repatriation or Reshoring of Manufacturing to the U.S. and UK: Dynamics and Global Production Networks or from Here to There and Back Again

There are three contrasting approaches to understanding the geography of production. The first approach emphasizes the importance of local agglomerations, the second intrafirm mechanisms, while the third highlights global relationships or global production networks (GPN) or global value chains. These explanations are partial, but complementary. This paper explores the restructuring of global production with a focus on the reshoring or repatriation of manufacturing production to the U.S. and UK. Our intention is to identify the drivers behind reshoring as the first stage toward developing a dynamic conceptual framework for understanding the global organization of production. Reshoring needs to be conceptualized by drawing on and combining approaches developed in GPN with micro‐approaches to understanding firms including the development of a geography of production tasks. The study is based on a theoretical mapping to inform an empirical analysis of reshoring in both countries to identify and conceptualize the quantitative and qualitative causal drivers behind this process. The evidence suggests that reshoring is sector‐dependent and is mainly driven by manufacturers’ cost‐management and quality strategies combined with the importance of manufacturing products close to market. This involves a “total manufacturing cost analysis” in which access to a set of tangible and intangible inputs are key drivers behind dynamics of GPN.     

Racial Wage Differences among Young Male Job Changers: The Relative Contribution of Migration,Occupation Change,Site Characteristics,and Human Capital

ABSTRACT We demonstrated racial differences in the relationship between migration, location, and predicted wages for young male workers who have changed employers. An Oaxaca decomposition allowed a measuring of the contributions of migration, occupation change, site features, and human capital to the racial wage gap. Migration decreases black–white wage differences, and wage compensation for site attributes favors white householders. Constraints on occupation choice and migration dampen the ability of blacks to improve wages. Because most job changes occur in the first ten years of a career, these results on young workers give important general insights into the origins and persistence of racial wage gaps.     

Regional Variations of Firm Births,Deaths and Growth Patterns in the UK, 1980–1991

One of the debates around new firm formation across sub‐national territories focuses on whether regional differences in industrial structure are more important influences than regional differences in individual industry performance. The present research, using Value Added Tax (VAT) registration data, attempts to make a contribution to this debate in the United Kingdom (UK) context using a shift‐share covariance model. Firm de‐registrations and, as a consequence, net changes in firm stocks are also analyzed with similar questions in mind. The findings show that although the effects of industrial mix are significant across most regions, in several key regional contexts the industrial competitive effect dominates. The issue of the role of regional industrial concentration forms a second major theme of this paper. This basically involves a questioning as to whether concentration is a positive or negative force for new firm formation. The results of this research indicate that industrial concentration, measured through localization, is more important for firm deaths than for firm births (although significant for both), but not particularly relevant to the understanding of the net outcome of entry and exit processes. In the UK, regions with higher levels of industry concentration seem to be associated overall with relatively lower levels of both firm births and deaths.