基于能量消耗分析的乳状液液滴粒径计算关系式

在油水混输管道中,存在着大量粒径大小不一的乳状液液滴,液滴粒径及分布对油水混合液的粘度有重要影响,从而在很大程度上影响管道的压降。因此,研究乳状液液滴粒径的计算关系式对于描述油水两相的流动特性以及准确计算管道压降具有重要意义。针对4种原油,通过油水体系的乳化实验,研究了搅拌转速、温度及含水率对乳状液液滴粒径的影响。研究发现,搅拌转速增大,乳状液液滴粒径减小;温度升高,乳状液液滴粒径增大,并且在低温下增大的趋势较显著;含水率增加,乳状液液滴粒径有减小趋势,但减小的幅度不大;以火用损率来表征剪切过程中的能量消耗,建立了基于剪切火用损率分析的乳状液液滴粒径计算关系式。     

经济密度、人口规模与环境污染——基于城市面板数据的实证分析

选取2005-2016年285个地级及以上城市数据,利用静态和动态短面板模型分析经济密度和人口规模对环境污染的影响,分析表明:经济密度与环境污染之间存在“倒U型”关系,人口规模扩大会抑制污染物排放;不同等级城市经济密度、不同规模城市人口对环境污染的影响方向一致,但影响程度有所差异;前期污染排放对当期具有正向影响,环境污染物排放存在路径依赖;经济发展水平、工业产值占比和对外开放也是影响污染物排放的重要因素,但各指标对三类污染物排放的影响方向和影响程度存在差异。据此认为,在综合考虑城市具体空间区位条件下,人口适度集聚,提高城市经济密度,优化产业结构以及加强环境监管是环境治理的重要方向。     

On the role of Islamic and conventional banks in the monetary policy transmission in Malaysia: Do size and liquidity matter?

This paper empirically investigates the impact of monetary policy on the credit supply of Islamic versus conventional banks of Malaysia using an unbalanced panel dataset over the period 2005-2016. While estimating the effects of three alternative measures of monetary policy on banks' credit supply, we include several bank-specific and macroeconomic variables in the specification as control variables. We provide strong evidence on the existence of the credit channel of monetary policy transmission mechanism in Malaysia. Yet, we show that Islamic banks respond considerably less to changes in monetary policy instruments as compared to their conventional counterparts. We also find that the monetary policy measures affect small-sized banks and less-liquid banks more as compared to large-sized and more-liquid banks. Our findings suggest that for an effective monetary policy, there is a vital need to consider the nature of Islamic banking while devising any monetary policy instruments to manage credit supply in the economy.     

Tick size and market quality: Simulations based on agent‐based artificial stock markets

This paper investigates the way that minimum tick size affects market quality based on an agent‐based artificial stock market. Our results indicate that stepwise and combination systems can promote market quality in certain aspects, compared with a uniform system. A minimal combination system performed the best to improve market quality. This is the first study to analyse tick size systems that remain at the theory stage and compare four types of system under the same experimental environment. The results suggests that a minimal combination system could be considered a new direction for market policy reform to improve market quality.     

Optimum government size and economic growth in case of Indian states: Evidence from panel threshold model

This paper investigates the relationship between optimum government size and economic growth using data of Indian states during 1990-91 to 2017–18. Our results derived from panel threshold regression model show a positive and significant impact of government size on economic growth within the estimated thresholds for both aggregate and sub-panels based on income and regions. Once the government size moves above the upper threshold level, then its impact declines and turns to be insignificant. Thus, our findings suggest the policymakers for maintaining the government size within the thresholds limit.     

Does size matter? Corporate social responsibility and firm performance in the restaurant industry

Despite an increasing number of hospitality studies on the link between corporate social responsibility (CSR) and corporate financial performance (CFP), the literature has predominantly focused on the CSR–CFP relation without considering moderating factors. Consequently, the current study introduces firm size as a potential moderator on the CSR–CFP relationship. Performing a two-way fixed-effects model by firm and year with Newey-West standard errors, this study finds that firm size moderates the effect of positive CSR on CFP while it does not moderate the effect of negative CSR on CFP in the U.S. restaurant context.     

Rising real wages,mechanization and growing advantage of large farms: Evidence from Indonesia

This paper examines dynamic patterns of land use, capital investments and wages in agriculture using farm panel data from Indonesia. The empirical analysis shows that with an increase in real wages that prevailed in both agricultural and non-agricultural sectors in rural areas, relatively larger farmers increased the size of operational farm land by renting in land as well as used more hired-in machines through machine rental and/or service providers, which induces the substitution of labor by machines. Machines and land are complementary and, consistently, the inverse farm size-productivity relationship tends to be reversed among relatively large holders. The results support growing (diminishing) advantage of large (small) farms in the presence of rapidly rising real wages and have food security policy implications to many Asian countries where real wages are rapidly rising and small farms are predominant.     

企业规模对专利产出影响的实证分析——基于1998—2010年上市公司经验证据

使用1998—2010年中国A股上市公司的年度数据,研究了企业规模对专利产出和专利密度的影响。结果表明:发明专利和实用新型专利与企业规模之间存在U型关系,外观设计专利与公司规模呈倒U型关系;三类专利的专利密度都与企业规模之间存在U型关系;企业的知识存量、成立时间、财务杠杆、所有制类型等企业内部因素以及市场集中度、企业所处区域等外部环境因素都对企业的专利产出有显著影响。据此提出企业创新发展路径假说。     

Stabilizing the market with short sale constraint? New evidence from price jump activities

We re-examine the impact of short-sale constraints (SSC) on market stabilization via realized jump activities during 2002–2009 to circumvent the reverse causality in identifying the policy effects of SSC. We observed that the abnormal downturns under tighter short sale constraints are significantly larger whereas there is no difference for abnormal upturns. Our empirical results survive across a sequence of robustness examinations controlled for market illiquidity. The findings do not support the claims by regulators that restraining short-sales can stabilize prices; instead, SSC has led to a less efficient market with stronger extreme downward returns.     

Land pressures,the evolution of farming systems,and development strategies in Africa: A synthesis

Evidence assembled in this special issue of Food Policy shows that rising rural population densities in parts of Africa are profoundly affecting farming systems and the region’s economies in ways that are underappreciated in current discourse on African development issues. This study synthesizes how people, markets and governments are responding to rising land pressures in Africa, drawing on key findings from the various contributions in this special issue. The papers herein revisit the issue of Boserupian agricultural intensification as an important response to land constraints, but they also go further than Boserup and her followers to explore broader responses to land constraints, including non-farm diversification, migration, and reduced fertility rates. Agricultural and rural development strategies in the region will need to more fully anticipate the implications of Africa’s rapidly changing land and demographic situation, and the immense challenges that mounting land pressures pose in the context of current evidence of unsustainable agricultural intensification, a rapidly rising labor force associated with the region’s current demographic conditions, and limited nonfarm job creation. These challenges are manageable but will require explicit policy actions to address the unique development challenges in densely populated rural areas.