Rotterdam model versus almost ideal demand system: will the best specification please stand up?

The Rotterdam model and the Almost Ideal Demand System (AIDS) are often applied in consumer demand systems modeling. Using Monte Carlo techniques, we determine which model performs best in recovering the true elasticities of demand. The AIDS model is usually used in linearized form. Since the Rotterdam model is also linear in a very similar form, comparison of the Rotterdam model and the AIDS model has been the subject of much speculation in the literature. We not only compare the linearized AIDS model with the Rotterdam model, but also with the full nonlinear AIDS. Copyright © 2008 John Wiley & Sons, Ltd.     

How Do Playful People Play? Gendered and Racial Leisure Perspectives,Motives, and Preferences of College Students

Playfulness is an aspect of personality that predisposes individuals to reframe boring situations into more amusing ones for themselves. This study extends knowledge about the playfulness construct by contrasting college students who were high or low in playfulness relative to the activity preferences they make, the motives they have, and their perspectives on their leisure time. Significant differences were found in perspectives and motives but not in activity preferences, leading to the conclusion that playfulness relates more to how individuals view their leisure and what they seek than in what they do. Only minor differences due to gender or race were observed.     

Boredom in Free Time: Relationships with Personality,Affect, and Motivation for Different Gender,Racial and Ethnic Student Groups

The propensity to experience boredom in free time was investigated by exploring relationships with the individual's demographic characteristics, personality, motivational orientation, and affective style assessed through group-administered questionnaires to 999 university students. The self-as-entertainment personality attribute consistently predicted the likelihood that students would be bored, and inverse relationships with extraversion and intrinsic motivational orientation were found for all student groups. Multiple regression analyses revealed that race, ethnicity, and gender were the only significant demographic predictors of the likelihood an individual would be bored in free time. Group similarities and differences in depicting students who were prone to experience boredom in free time are described.     

Theorizing about play: Critique and direction

This paper presents a review of the extant theoretical models of play behavior. Play theories can be clustered insofar as they suggest different motivations and presuppose distinct underlying mechanisms for playful behavior. The biological view sees the motivation to play as instinctually determined and suggests a genetically inherited predisposition to emit playful responses. The play theories discussed under this heading stress the importance of homeostatic mechanisms and the transformation of energy states as determining when play will occur. The play theories subsumed under the environmental view focus on the typology of play activities and suggest that play is only a subclass of behavior to which the principles of environmental contingencies and reinforcement in learning also apply. Cognitive explanations impart the causation to play as a function of the information‐processing mechanisms of the individual. Within this framework play is defined as a state of mind rather than an activity and it is the player's perception of his environment, in interaction with cognitive processes, which determines the characterization of a playful response. Although the theoretical models of play are discussed within these three perspectives, it is suggested that it is more useful to view these three headings as lying on a continuum, since a review of the theories shows a gradual transition and later cognitive‐based models still presume an internal biological drive. The difficulties with each perspective are discussed and a synthesis is provided which extrapolates some of the tenets of each of the models, as well as presenting an alternative and interactive view of play behavior.     

炫酷改装车

BRABUS把奔驰升级为巴博斯爱好汽车的朋友们,一定听过这样的一句话:德国人的血管里流淌的不是血液,是汽油!如此博得全球汽车业认同的,不仅是众所周知的德国豪车品牌,更有其体系成熟的改装文化.成立于1977年的德国品牌BRABUS(巴博斯)正是其中的先驱者.巴博斯自创立之初,便专门真对奔驰汽车进行定制改装.早在1992年,巴博斯便在奔驰600型轿车上搭载了509马力/375千瓦的巴博斯6.9升V12发动机,使改装后车速可高达300公里.自此,巴博斯开始了其顶级12缸发动机的研发与制造.时至今日,巴博斯的产品涵盖了引擎移植、引擎性能加强、空气动力性能提升、高质量合金轮毂、动感与舒适兼具的悬挂系统、高性能制动系统以及各种高品质的个性化内饰改装服务.     

Implications of the global growth slowdown for rural poverty

Over the past 25 years, higher growth in developing countries has contributed to a dramatic fall in global poverty, although poverty rates in rural areas remain higher than in urban areas. Unfortunately, projected growth rates have fallen in recent years; this article examines the impact of this slowdown on the poor, particularly the rural poor. It first uses a global model to assess the impacts of lower productivity on key price and income variables. It then uses microsimulation models for almost 300,000 households to assess the impacts on their real incomes. Although poverty rates overall are projected to fall substantially, the poorest countries see the greatest slowdown in poverty reduction, with over 5% of their population projected to remain below the poverty line. In addition, poverty rates will remain alarmingly high in many countries. Overall, 38 million fewer people will leave extreme poverty compared to earlier projections. Farm households are at particular risk in middle‐income countries, with over 1.5% more of the farming population remaining trapped in poverty than previously estimated. By 2030, average extreme poverty in rural areas is projected at about 7.5%, rather than 7.1% under the earlier growth projections. Clearly, a strong focus on policies for poverty reduction will be vital for eliminating poverty by 2030.     

Economic growth,convergence, and agricultural economics

After nearly two centuries of lagging behind the industrial countries, growth in many developing countries has surged since the early 1990s. This outperformance has major implications for almost all areas of agricultural economics and, if continued, will likely do so into the future. This article aims to identify the key ways in which the changes in rich and poor country growth rates matter for agricultural economists, as a basis for formulating better research agendas. A key impact arises through sharp increases in demand for agricultural resources as demand for livestock products increases. This changing structure of food demand has important implications for nutrition studies and policies, with the emergence of a double burden of malnutrition. On the supply side, growth in developing countries tends to increase domestic food supply, which is also boosted by increases in research and development spending. Growth in developing countries both stimulates and benefits from increases in infrastructure investment, evaluation of which requires new analytical tools. Negative impacts include the contribution of increased demand for livestock products to global greenhouse gas emissions. In terms of trade policy, growth in developing country is tending to lead to convergence of agricultural policies with the pattern of assistance seen in today's developed countries, raising concerns about the future need to deal with collective action problems, particularly those that increase the volatility of world prices.