劳动力成本与利润差异对制造业升级的影响研究

引入单位劳动力成本和人均利润,考量劳动力成本与利润影响制造业升级的效应。结果表明：样本期间内虽然劳动力成本快速上涨,但劳动生产率增速更快,制造业整体单位劳动力成本没有上升,且有小幅下降,劳动密集型制造业仍有一定综合成本优势,但其人均利润低于制造业整体水平,比重总体下降,发展后劲不足,须转型升级;资本密集型虽然利润率相对较低,但人均利润为最高,比重不断上升,仍应是当前发展的重点;技术密集型比较优势不明显,急需突破核心技术,提高综合国际竞争力。     

农作物面积抽样单元空间变异性及其对抽样外推效率的影响

［目的］联合遥感和传统抽样方法的空间抽样技术是进行大区域农作物面积监测的有效手段。但传统抽样要求抽样单元间相互独立,并未考虑到区域农作物空间变异性的存在对农作物面积空间抽样效率是否有影响及其影响程度如何,从而限制了农作物面积监测的效率和精度。［方法］文章以吉林省德惠市为研究区,利用变异函数分别对10种抽样单元尺度内玉米和水稻种植面积的空间变异性进行定量评价。选择3种空间抽样方案（简单随机抽样、系统抽样、分层抽样）,分别计算不同空间变异程度下的样本容量（n）、抽样相对误差（Re）和总体总值估计量的变异系数（CV（Y︿））作为空间抽样效率的评价指标,定量分析空间变异性对农作物面积空间抽样效率的影响,提出适宜空间变异农作物的空间抽样优化方案。［结果］(1)玉米和水稻面积的空间变异性（反映为基台值C0+C）均随着抽样单元尺度的增加逐渐而减小,其中500m×500m和2 500m×2 500m抽样单元尺度下农作物面积的空间自相关程度相对最小。(2)相同抽样比下,农作物面积在3种抽样方法下的相对误差和变异系数均随着空间变异性的减小（抽样单元尺度增加）逐渐增大,其中玉米和水稻在分层抽样条件下的相对误差和变异系数具有相对最小值,分别限制在10%和20%以内,其次为系统抽样（Re<40%,CV（Y︿）<88%）和简单随机抽样（Re<50%,CV（Y︿）<75%）。 在抽样方法被选定的情况下,两种农作物的分层抽样相对误差变化率随着抽样比的增加迅速降低,当抽样比增至5%时,其相对误差和变异系数的变化率基本趋于稳定,继续增加抽样比来提高抽样精度的效果甚微。 在3 500m×3 500m抽样单元尺度内,按5%抽样比确定的样本容量对玉米和水稻面积进行分层抽样时,可达到95%的抽样精度（Re<5%）。 综合农作物在不同抽样单元尺度下的空间变异特征和空间抽样效率,基于2 500m×2 500m的抽样单元尺度和5%抽样比进行分层抽样的空间变异性农作物空间抽样方案是一种高精度、低成本、代表性强的空间抽样方案。［结论］该研究为区域农作物面积抽样调查方法的改善和抽样效率的提高提供技术支持和参考依据。     

上市公司治理结构效率评估

建立有效的公司治理结构无论对于所有者还是对于投资者而言都是有利的。基于诸如委托代理人理论、不对称信息理论等前沿理论成果,兼顾考虑到正在发展中的中国资本市场环境,本文运用数据包络分析(DEA)分析和研究了中国上市公司治理结构的有效性和效率。     

城镇居民消费过度敏感性的统计分析

本文在文献综述的基础上,指出了现有研究中的不足,即缺少不同收入阶层的消费过度敏感性的分析以及由于样本容量的不足导致模型拟合及预测能力不强。本文主要利用panel data模型分析了我国城镇不同收入阶层居民消费的过度敏感性,验证出各阶层都存在着过度敏感性,且过度敏感性的大小在各阶层中呈现倒"草帽"型分布。     

抽油机双功率电机在安塞油田应用的节能分析

在油田企业,机械采油电力驱动装备俱为电机,约占总耗电量的80％。在实际生产中,很多抽油机电机处于轻载、低效、高耗的运行状态,电能浪费严重。因此,电机节能降耗是解决油田节电降耗、降低开采成本的主要方向。通过分析抽油机光杆功率与电机额定功率的理论关系,结合2011年安塞油田引进安装双功率电机的现场应用效果,阐述其工作原理和技术指标,并根据现场监测得到电能参数进行客观、准确的分析评价。     

Are margins more procyclical in concentrated industries?

In a series of recent papers, Domowitz, Hubbard and Peterson (DHP) have explored the temporal behavior of price-cost margins in a panel of 284 four-digit SIC industries. This paper reexamines DHP's apparent finding of more procyclical margins in concentrated industries, concluding that it is not robust. The result appears to arise from long-run trend correlations between margin and demand levels, rather than from short-run cyclical effects. Consistent with DHP, prices are found to be stickier and unit costs more countercyclical in concentrated industries. However, (1) an omitted variables bias is uncovered which substantially reduces the estimated cyclical effect on costs, and (2) prices are found to be more flexible in low concentration, low-PCM industries than DHP estimate. With prices more responsive to growth in demand and a countercyclical effect on cost of substantially lower magnitude, margins are thus estimated to bemore procyclical in less concentrated industries. This finding explains the relative rise in low concentration margins in the sixties which, in turn, helps account for the declining significance of the cross-sectional concentration-margins relationship.I would like to acknowledge helpful comments from Roy Rotheim, and two anonymous reviewers.     

The impact of maize price shocks on household food security: Panel evidence from Tanzania

Using three waves (2008/09, 2010/11, 2012/13) of the Tanzanian National Panel Survey, this study investigates the impact of maize price shocks on household food security. Between 2008/09 and 2012/13, calorie intake stagnated for urban households, yet sharply deteriorated for rural households. The latter was driven by a significant decline in the consumption of the major staple maize which showed strongest price hikes among all major food items. Fixed-effects regressions indicate a clear negative relationship between maize prices and average household energy intake. Almost all population groups were found to be negatively affected by maize price shocks, with rural landless households being the most vulnerable group. In particular, a 50 percent rise in maize prices decreases caloric intake for rural (urban) households on average by 4.4 (5.4) percent, and for rural landless households by 12.6 percent. Results further indicate that subsistence agriculture can act as an effective strategy to insure against food price volatility.     

经济全球化对我国环境污染影响的实证研究——基于行业面板数据

我国经济的高速发展和伴生的环境污染问题,是在我国经济加速融入全球经济的背景下发生的。本文在阐述经济全球化的含义和构建经济全球化指数的基础上,基于我国33个工业行业1997-2005年的面板数据,采用PCSE稳健估计,发现经济全球化显著降低了我国的环境污染水平,同时得出了我国规模效应、技术效应、结构效应以及要素禀赋等的结果。     

国际贸易对我国行业间收入分配的影响——基于制造业面板数据的实证分析

本文运用我国1998-2006年27个制造业行业的面板数据对国际贸易的行业间收入分配效应进行了实证研究。研究发现,从总体上看,出口对行业相对工资有正向的上拉作用,进口对行业相对工资有负向的下拉作用。但进出口对不同类型行业的影响程度和方向不同,出口贸易对资本密集型和劳动密集型制造业行业的相对工资均有上拉作用,且对前者的促进作用大于后者;进口贸易对劳动密集型制造业行业的相对工资有下拉作用,而对资本密集型制造业行业的相对工资有上拉作用。基于上述结论,促进出口,提高劳动密集型产品的附加值,适当控制最终消费品等产品的进口,有助于缩小行业收入差距。     

Do R&D and ICT affect total factor productivity growth differently?

We analyze the effect of ICT and R&D on total factor productivity (TFP) growth across different industries in Sweden. R&D alone is significantly associated with contemporaneous TFP growth, thus exhibiting indirect effects. Although there is no significant short-run association between ICT and TFP, we find a positive association with a lag of seven to eight years. Thus, R&D affect TFP much faster than ICT-investments. We also divide ICT capital into hardware and software capital. To our knowledge, this distinction has not been made in any previous study analyzing TFP at the industry level. The results show that lagged hardware capital services growth is significantly associated with TFP growth. Hence, investments complementary to hardware are needed to reap the long-run TFP effects from reorganizing production.