The Effects of Social Networks on Wages of Rural-Urban Migrants: An Empirical Analysis Using Data From the Pearl River Delta

随着我国城市化进程的加快，从农村到城市从事非农工作的农民工群体不断扩大，并逐渐分化成新生代和老一代两个群体。在农民工求职的过程中，社会关系网络依然起着主导作用，但新生代农民工对社会关系网络的依赖减少，求职渠道呈现出多元化的趋势。在这一背景下，研究社会关系网络对农民工工资水平的影响，对提高农民工的劳动力市场就业结果和促进和谐社会的发展具有重要的现实意义。 本文利用中山大学社会科学调查中心于2006、2008、2009年对珠三角地区九城市的农民工调查访问的样本数据，以是否通过亲友介绍求职作为农民工社会关系网络的代理变量，在对样本数据进行描述性统计分析的基础上，利用稳健加权最小二乘法实证研究了社会...With the accelerating process of urbanization, the number of rural-urban migrants continues to increase, and they are gradually divided into two different groups, the young generation and the old generation. Social networks still play dominant roles in rural-urban migrants’ job search, but the young generation is less dependent on them and their job search channels tend to be diversified. So the s...学位：经济学硕士院系专业：经济学院_西方经济学学号：1532013115219

Allelic imbalance and abnormal expression of FHIT in endemic nasopharyngeal carcinoma: association with clinicopathological features

Natural Science Fund of Fujian Province, ChinaThe FHIT gene is involved in the pathogenesis of many cancers. The aim of this study was to investigate allelic imbalance (AI) pattern at FHIT locus and alteration of FHIT gene in nasopharyngeal carcinoma (NPC) and analyzed potential correlation between AI, FHIT mRNA expression and clinicopathological factors. We examined AI, including loss of heterozygosity (LOH) and microsatellite instability (MSI), at FHIT locus in 41 cases of NPC by microsatellite analysis and FHIT gene status in 30 cases of NPC by nested reverse transcriptase-polymerase chain reaction and DNA sequencing. The frequencies of LOH and MSI at FHIT locus in NPC were 70.7% (29/41) and 36.6% (15/41), respectively. Thirteen of thirty (43.3%) NPCs exhibited aberrant FHIT transcripts. LOH and abnormal FHIT expression were correlated with advanced clinical stage and higher titers of immunoglobulin (Ig) A against Epstein-Barr virus capsid antigen (EBVCA-IgA) (p < 0.05). Abnormal FHIT expression was also correlated with tumor recurrence (p < 0.05). MSI was correlated with early clinical stage and higher titers of EBVCA-IgA (p < 0.05). AI at FHIT locus is a common event and contributes to genetic imbalance in NPC. The abnormalities of FHIT, presumably associated with genetic imbalance at FHIT locus, might be involved in the development and the tumor recurrence of NPC

鸟类传播捕食线虫真菌的可能性探究

微生物多样性的空间分布格局及驱动机制是微生态学研究的核心问题,从鸟类传播微生物的视角开展研究,可能有助于理解该问题,为此,在云南省大理州采集不同野生鸟类喙、脚趾和脚爪、翅下覆羽和尾下覆羽部位的棉拭子及粪便样品共379份,明确不同鸟类携带捕食线虫真菌(nematode-trapping fungi,NTF)的情况,探究不同鸟类传播NTF的可能性。本研究仅从鸟类脚趾和脚爪样品中检出1属(Arthrobotrys)4种9株NTF,检出率为8.7%。从迁徙状态看,迁徙途中候鸟的检出率为3.6%,已到达越冬地或繁殖地的候鸟检出率为15.0%,留鸟检出率为12.5%。从生态类群看,林鸟中主要在乔木灌丛间活动的鸟类检出率为0,在地面上活动的鸟类检出率为18.2%; 水鸟中游禽检出率为10.7%,涉禽检出率为11.1%。研究表明鸟类能够通过脚趾和脚爪携带NTF,鸟类的生境选择决定其携带NTF的能力,NTF中的广布种更容易被鸟类携带和传播。鸟类对微生物的携带和传播作用,及其对微生物多样性空间格局的影响需要纳入相关研究范畴

电渗析真空膜蒸馏集成膜法回收离子液体

为了达到最大限度回收离子液体循环再利用的目的,用电渗析-真空膜蒸馏集成膜法浓缩低浓度质量分数(下同)为1%~5%的离子液体水溶液,实现了有效可操作的膜集成浓缩过程控制。分析了膜集成过程中电渗析施加电压、料液初始浓度和料液体积比等操作参数对优化工艺的影响,获得了此电渗析过程的最高浓缩浓度。当电渗析可浓缩AMIMCl至最大浓度时,即可切换至真空膜蒸馏过程深度浓缩,最终可将AMIMCl水溶液浓缩至48.2%

电渗析-真空膜蒸馏集成膜法回收离子液体

为了达到最大限度回收离子液体循环再利用的目的,用电渗析-真空膜蒸馏集成膜法浓缩低浓度质量分数(下同)为1%~5%的离子液体水溶液,实现了有效可操作的膜集成浓缩过程控制。分析了膜集成过程中电渗析施加电压、料液初始浓度和料液体积比等操作参数对优化工艺的影响,获得了此电渗析过程的最高浓缩浓度。当电渗析可浓缩[AMIM]Cl至最大浓度时,即可切换至真空膜蒸馏过程深度浓缩,最终可将[AMIM]Cl水溶液浓缩至48.2%

Aberrant Expression Levels of MTA1 and RECK in Nasopharyngeal Carcinoma: Association With Metastasis, Recurrence, and Prognosis

Objectives: We investigated the expression and clinical value of MTA1 and RECK genes in patients with nasopharyngeal carcinoma (NPC). Methods: We examined MTA1 and RECK expression in nasopharyngeal tissue from patients with chronic nasopharyngitis, lymph nodes with metastasis of NPC, and primary NPC tumor tissue by means of in situ hybridization and analyzed their correlation with the clinicopathologic features of NPC. Results: The positive expression of MTA1 in the NPC tissues and metastatic lymph nodes was significantly higher than that in the chronic nasopharyngitis tissues (p 0.05). However, they had a positive correlation with cervical lymph node metastasis, tumor recurrence, and 5-year overall survival rate of the patients with NPC (p < 0.05). Moreover, multivariate analysis showed that MTA1 and RECK expressions were independent prognostic factors for survival (p < 0.05). Conclusions: The conversely abnormal expression levels of MTA1 and RECK may be collectively involved in progression of malignancies and may serve as molecular predictors for metastasis, recurrence, and prognosis of NPC.Medical Innovation Program Fund of Fujian Province, China [2011-CXB-35