Asymmetric price transmission has been the subject of considerable attention in agricultural economics. It is not only important because it may point to gaps in economic theory, but also because its presence is often considered for policy purposes to be evidence of market failure. In this paper we survey the literature on asymmetric price transmission. A wide variety of often conflicting theories of, and empirical tests for, asymmetry co‐exist in this literature. We classify the different types and causes of asymmetric price transmission and describe the econometric techniques used to quantify it. We also briefly review the results of empirical applications. Outstanding methodological problems and suggestions for future research are discussed. Our main conclusion is that the existing literature is far from being unified or conclusive, and that it has often been largely method‐driven, with little attention devoted to theoretical underpinnings and the plausible interpretation of results. Hence, much interesting theoretical and empirical work remains to be done.
Historically, farmers and hunter-gatherers relied directly on ecosystem services, which they both exploited and enjoyed. Urban populations still rely on ecosystems, but prioritize non-ecosystem services (socioeconomic). Population growth and densification increase the scale and change the nature of both ecosystem- and non-ecosystem-service supply and demand, weakening direct feedbacks between ecosystems and societies and potentially pushing social-ecological systems into traps that can lead to collapse. The interacting and mutually reinforcing processes of technological change, population growth and urbanization contribute to over-exploitation of ecosystems through complex feedbacks that have important implications for sustainable resource use.
BackgroundTo investigate the association between environmental risk factors, eating away from home, and increasing BMI of Chinese adults.MethodsParticipants were selected from the recent four waves (2004, 2006, 2009, and 2011) of the China Health and Nutrition Survey (CHNS). 10633 participants, including 5084 men and 5549 women, were used in the analysis. 24-h dietary recall data for three consecutive days with information on the time and place of consumption were collected. Nearby restaurants were measured by the number of fast food outlets, indoor restaurants, and food stands in the neighborhood. Random effects multivariable regression was used to assess associations between these variables.ResultsPeople living in neighborhoods with large numbers of indoor restaurants are more likely to eat away from home (p<0.05). Higher frequency of eating away from home is positively associated with BMI, but this effect is only significant for men (p<0.05). Moreover, while eating dinner or breakfast away from home contributes to BMI increase for men (p<0.05), no such association is found for lunch.ConclusionEating dinner and breakfast away from home is positively associated with BMI for Chinese men. Labeling energy and portion size for the dishes served in indoor restaurants is recommended in China.
Scientists understand how global ecological degradation is occurring but not why it seems to be so difficult to reverse. We used national-level data and a mathematical model to provide an empirical test of the hypothesis that national economies display two distinct economic regimes that are maintained by self-reinforcing feedbacks between natural resources and society. Our results not only support previous findings that two distinct groups exist, but also show that countries move toward one of these two different equilibrium points because of their different patterns of natural resource use and responses to population growth. At the less economically developed equilibrium point maintained by "green-loop" feedbacks, human populations depend more directly on ecosystems for income. At the more economically developed equilibrium point maintained by "red-loop" feedbacks, nonecosystem services (e.g., technology, manufacturing, services) generate the majority of national gross domestic product (GDP), but increasing consumption of natural resources means that environmental impacts are higher and are often exported (via cross-scale feedbacks) to other countries. Feedbacks between income and population growth are pushing countries farther from sustainability. Our analysis shows that economic growth alone cannot lead to environmental sustainability and that current trajectories of resource use cannot be sustained without breaking feedback loops in national and international economies.
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