The estimated ex ante economic impact of Bt cowpea in Niger,Benin and Northern Nigeria

Genetically modified (GM) crops could increase economic growth and enhance living standards in Africa, but political issues have slowed the use of biotechnology. This is the first study that assesses the potential impact of GM crops in Africa while considering the preferences of producers and consumers towards GMOs as well as the income and price risks they face. The study uses a choice experiment to estimate the ex ante economic impact of a novel technology, Bacillus thuringiensis (Bt) cowpea, on producers and consumers in Benin, Niger and northern Nigeria. The experiment involves the simulation of a market transaction similar to those in open air markets in West Africa. During the market simulation, respondents are informed about the advantages and disadvantages, including health risks, of Bt cowpea. The results from the study suggest that cowpea growers and consumers in Benin and northern Nigeria prefer Bt to conventional cowpea for health safety reasons. The results estimate that social welfare in Benin, Niger and northern Nigeria would increase by at least US$11.82 per capita annually with Bt cowpea, if seed sectors are operating smoothly. With inefficiencies in seed sectors and the potential for cowpea acreage increase, the estimated social welfare increase in the region would be about US$1.26 per capita annually.     

Food consumption impacts of adherence to dietary norms in the United States: a quantitative assessment

Promotion of adherence to healthy-eating norms has become an important element of nutrition policy in the United States and other developed countries. We assess the potential consumption impacts of adherence to a set of recommended dietary norms in the United States using a mathematical programming approach. We find that adherence to recommended dietary norms would involve significant changes in diets, with large reductions in the consumption of fats and oils along with large increases in the consumption of fruits, vegetables, and cereals. Compliance with norms recommended by the World Health Organization for energy derived from sugar would involve sharp reductions in sugar intakes. We also analyze how dietary adjustments required vary across demographic groups. Most socio-demographic characteristics appear to have relatively little influence on the pattern of adjustment required to comply with norms. Income levels have little effect on required dietary adjustments. Education is the only characteristic to have a significant influence on the magnitude of adjustments required. The least educated rather than the poorest have to bear the highest burden of adjustment. Our analysis suggests that fiscal measures like nutrient-based taxes may not be as regressive as commonly believed. Dissemination of healthy-eating norms to the less educated will be a key challenge for nutrition policy.     

Productivity growth, catching-up and uncertainty in China''s meat trade

The potential role of China as a major importer of agricultural products, and the likely impact on world markets has been a topic of considerable debate over the past decade. In this paper, we focus specifically on the livestock sector and develop a detailed analysis of productivity growth in China’s pig and poultry production along with projections of China’s likely meat trade in the year 2010. We use a general equilibrium model which permits us to explore the sensitivity of our projections to macro-economic uncertainty as well as uncertainty in livestock productivity growth rates. Our analysis shows that China’s net trade position is very sensitive to both of these factors. With high livestock productivity growth and a slow-down in the rest of the economy, China could be a substantial competitor in export markets by 2010. On the other hand, slow productivity growth in livestock production, coupled with a rapidly growing macro-economy could transform China into a major market for future meat exports.     

Regulatory risk, market uncertainties, and firm financing choices: Evidence from U.S. Electricity Market Restructuring

Based on the universe of rate-regulated electric utilities in the U.S., we examine why firms alter their financing decisions when transitioning from a regulated to a competitive market regime. We find that the significant increase in regulatory risk after the passage of the Energy Policy Act, state-level restructuring legislations, and divestiture policies have reduced leverage by 15 percent. Policies that encouraged competition, and hence increased market uncertainty, lowered leverage by another 13 percent on average. The ability to exercise market power allowed some firms to counter this competitive threat. In aggregate, regulatory risk and market uncertainty variables reduce leverage between 24.6 and 26.7 percent. We also confirm findings in the literature that firms with higher profitability and higher asset growth have lower leverage, and those with more tangible assets are more levered. Firms with greater access to internal capital markets and those with a footloose customer segment use less debt, while those actively involved in trading power in the wholesale market use more debt.     

步进电机驱动电路设计与实现研究

在分析了步进电机驱动芯片L297/L298的性能、结构的基础上,结合MCS-51单片机,介绍实现驱动步进电机的一种简单方法。文中给出了控制原理图。实测表明,利用该方法设计的步进电机驱动系统具有硬件结构简单、软件编程容易和价格低廉的特点。     

How institutions affect export quality

We examine the relationship between a country's institutional environment and the quality of its exports. Institutional factors such as widespread corruption, inefficient bureaucracy, and high risk of expropriation of private property by government can create uncertainty among producers and discourage them from investing and innovating over the long term. This can limit the ability of producers to improve the quality of their exports in the future. We find some evidence that a better institutional environment (i.e. lower corruption, more efficient bureaucracy and more secure property rights) is associated with better export quality. After accounting for potential endogeneity between institutional and economic variables, we conclude that better institutions lead to improvements in export quality. Among the institutional factors considered in this article, corruption appears to be most robustly associated with export quality. These results have important implications for policymakers.     

The age-productivity gradient: Evidence from a sample of F1 drivers

Estimating the effect of aging on productivity requires clean measures of productivity. Additionally, one needs to control for unobserved heterogeneity at the worker, firm and worker/firm level, to account for the role of experience and to correct for selection bias. We tackle these issues exploiting a panel of Gran Prix Formula One drivers, which provides a unique setting to single out the data requirements needed to credibly estimate the effect of age on productivity. Results robust to the inclusion of worker, firm and match effects show that the age-productivity link has an inverted U-shape profile with a peak at the age of 30-32. The use of repeated cross-sections of individuals also produces consistent results provided that cohort effects are properly accounted for. Relying on team-average measures of productivity makes instead inference harder.     

Entrepreneurship: Origins and returns

We examine the origins and outcome of entrepreneurship on the basis of exceptionally comprehensive Norwegian matched worker-firm-owner data. In contrast to most existing studies, our notion of entrepreneurship not only comprises self-employment, but also employment in partly self-owned limited liability companies. Based on this extended entrepreneurship concept, we find that entrepreneurship tends to be profitable. It also raises income variability, but the most successful quartile gains much more than the least successful quartile loses. Key determinants of the decision to become an entrepreneur are occupational qualifications, family resources, gender, and work environments. Individual unemployment encourages, while aggregate unemployment discourages, entrepreneurship.     

Gender differences in competitiveness: Empirical evidence from professional distance running

A large body of literature documents the existence of a considerable and persistent gender gap in competitiveness. Using longitudinal data from professional distance running covering a period of nearly 40 years (1973-2009) I first confirm the findings of most previous studies by demonstrating that on average the women's races were - for most years - indeed less competitive than the men's contests. Closer inspection of the data, however, reveals that the women's races over distances with large amounts of prize money and/or prestige at stake (5000 m track, 10,000 m road, half marathon, and marathon) have always been particularly “balanced”. Moreover, although it still exists, the gender gap has considerably narrowed over the years. These findings are not compatible with the hypothesis that gender differences in competitiveness reflect evolved biological differences and/or psychological predispositions. It is, however, compatible with two other (complementary rather than substitute) hypotheses: due to changing socio-cultural conditions boys and girls are today socialized similarly in many parts of the world and due to the increasing returns to success (i.e. identical prize money levels and distributions) women are nowadays motivated to train as hard as comparably talented men.