最低工资与企业价格加成

本文利用1998-2007年中国工业企业数据库和各地级市最低工资数据,从价格加成视角考察了最低工资对企业经营绩效和资源配置效率的影响,并重点探讨了可能的影响渠道。研究发现:最低工资上涨显著降低了企业的价格加成,削弱了企业盈利能力。这意味着在短期最低工资潜在的成本效应大于其生产率提升效应。这一影响对不同特征的企业存在异质性,企业资本密集度和平均工资越低,其价格加成受到最低工资的影响越大。此外,最低工资上涨还会降低城市行业内价格加成分散度,有利于行业内资源错配的改善。国家自然科学基金面上项目(71273167);;上海市教育委员会、上海市教育发展基金会2014年度“曙光计划”项目(14SG51);;霍英东青年教师基础研究课题(141085)的资

The Effect of Minimum Wage Standards on Firms' Export Duration

本文基于1998-2007年中国工业企业数据库数据,利用生存分析法考察了最低工资对中国企业出口持续时间的影响。研究发现,在控制了企业和城市层面主要特征变量后,最低工资上涨不仅没有降低企业的出口持续时间,反而提高了其在出口市场的生存概率,该结果在考虑了内生性问题后仍然显著。通过对最低工资与企业出口持续时间可能的影响机制进行检验,本文发现企业通过增加固定资产投资来提高企业生产率是导致最低工资对企业出口持续时间呈正向影响的重要渠道。This paper investigates the impact of the rising minimum wage on Chinese firms' export duration in the export markets through a survival analysis on the matched data between the ASIF data and the Chinese City Statistical Yearbook between 1998 and 2007. Our study shows that,after controlling the firmand city-level main characteristic variables,the increment of the minimum wage has positive effects on firms' export duration and improves the survival probability in the export market. This result is robust even if we consider the endogenous problem. Moreover,the empirical analysis demonstrates that firms will improve their productivities by substituting capital for labor,which may contribute to the positive effect of the minimum wage on the export duration.国家自然科学基金面上项目“我国城市贸易结构空间分布研究”(71273167)、“政策干预对我国不同组织模式贸易出口复杂度的影响”(71373156);; 教育部人文社会科学研究规划基金项目“中国贸易关系的持续时间及其在贸易政策调整中的应用”(13YJA790152);; 上海对外经贸大学国家开放与发展研究院价值链项目(E1A-6116-15-214);; 上海市教委“曙光计划”项目“我国城市比较优势研究”(14SG51)的资

Bioaccumulation and biotransformation of inorganic arsenic in Ruditapes philippinarum

Arsenic (As) is a ubiquitous toxic metalloid, and its toxicity depends greatly on its chemical speciation. Marine mollusks are apt to bioaccumulation of high arsenic contents because of their living habits. In this study, the bioaccumulation and biotransformation of the clam Ruditapes philippinarum were investigated after waterborne exposure to arsenite (As (Ⅲ)) or arsenate (As (Ⅴ)) for 14 days. The results showed that arsenic uptake increased with increasing arsenic concentration in the seawater, while gills of R. philippinarum showed the limited ability to bioaccumulate inorganic arsenic from seawater, with no significant difference compared with control group following waterbone 10 mug/L As (Ⅲ) and As (Ⅴ) exposure for 14 days. The bioavailability of As (Ⅲ) was slightly higher than that of As (Ⅴ) to R. philippinarum, and arsenic was easier to be accumulated in digestive glands. The results demonstrated the As biotransformation in the clams included As (Ⅴ) reduction, As (Ⅲ) oxidation, and methylation. Arsenobetaine (AsB) and dimethylarsinic acid (DMA) was the major arsenic speciation in all treatments, while monomethylarsonic acid (MMA) contents decreased significantly after exposure, indicating that MMA can be quickly metabolized or converted into other arsenic speciation in the rate-limiting conversion reaction of inorganic arsenic. Inorganic arsenic in gills was mainly converted to DMA, but AsB in digestive glands, indicating the different transformation efficiency in different tissues. In summary, the results provided an important basis for elucidating the arsenic bioaccumulation and biotransformation mechanism in R. philippinarum and provided theoretical basis for shellfish breeding and food safety