WHAT ACCOUNTS FOR THE DECLINE IN CRIME?*

In this article we analyze recent trends in aggregate property crime rates in the United States. We propose a dynamic equilibrium model that guides our quantitative investigation of the major determinants of observed patterns of crime. Our main findings can be summarized as follows: First, the model is capable of reproducing the drop in crime between 1980 and 1996. Second, the most important factors that account for the observed decline in property crime are the higher apprehension probability, the stronger economy, and the aging of the population. Third, the effect of unemployment on crime is negligible. Fourth, the increased inequality prevented an even larger decline in crime. Overall, our analysis can account for the behavior of the time series of property crime rates over the past quarter century.     

Mining and Social Movements: Struggles Over Livelihood and Rural Territorial Development in the Andes

Social movements have been viewed as vehicles through which the concerns of poor and marginalized groups are given greater visibility within civil society, lauded for being the means to achieve local empowerment and citizen activism, and seen as essential in holding the state to account and constituting a grassroots mechanism for promoting democracy. However, within development studies little attention has been paid to understanding how social movements can affect trajectories of development and rural livelihood in given spaces, and how these effects are related to movements’ internal dynamics and their interaction with the broader environment within which they operate. This paper addresses this theme for the case of social movements protesting contemporary forms of mining investment in Latin America. On the basis of cases from Peru and Ecuador, the paper argues that the presence and nature of social movements has significant influences both on forms taken by extractive industries (in this case mining) and on the effects of this extraction on rural livelihoods. In this sense, one can usefully talk about rural development as being co-produced by movements, mining companies, and other actors, in particular the state. The terms of this co-production, however, vary greatly among different locations, reflecting the distinct geographies of social mobilization and of mineral investment, as well as the varying power relationships among the different actors involved.     

江苏居民收入分配差距及其治理分析

改革开放以来,江苏居民收入普遍提高,人民生活得到很大改善,但近年来居民收入开始出现差距并且日益扩大,已成为影响社会稳定和经济发展的重要问题。文章首先分析了江苏居民收入分配的现状,然后剖析了影响居民收入分配差距过大的成因,在此基础上提出了防止居民收入差距过大的治理对策。     

混合拉曼/EDFA放大器及其在DWDM中的应用

本文综述了混合拉曼／掺饵光纤放大器（HFA）的工作原理，结构和特点，介绍了4类HFA基本结构及其实验结果，并通过介绍近年来各类HFA在密集波分复用（DWDM）系统中的应用表明了HFA在带宽，增益和噪声特性方面的优点。     

CREDIT CYCLES REDUX*

Theoretical studies have shown that under unorthodox assumptions on preferences and production technologies, collateral constraints can act as a powerful amplification and propagation mechanism of exogenous shocks. We investigate whether or not this result holds under more standard assumptions. We find that collateral constraints typically generate small output amplification. Large amplification is obtained as a “knife‐edge” type of result.     

Regional innovation and small high technology firms in peripheral regions

This paper highlights the difficulty of developing HT firms in a peripheral region of Spain. Although the endogenous development of HT firms in these regions is possible, their evolution depends on more central regions. The firm's geographical location and the type of HT production are the most important endogenous factors governing the firm's success.     

A note on forecasting international tourism demand in Spain

This paper considers the extent to which price and income proxy variables help in forecasting tourist demand in Spain. Contrary to some recent studies, we found that the inputs' contribution in terms of fitting and forecasting is nil when compared with alternative univariate models. Whether these findings are the results of the restrictions embedded in building the proxy inputs or in a poor specification of the dynamics of these models remains to be seen. We also contend that when dealing with medium, long-term forecasting comparisons, the use of the traditional aggregate accuracy measures like RMSE and MAPE help very little in discriminating among competing models. In these situations, predicted annual growth rates may be a better alternative.     

Scarcity and appropriative competition

This paper formalizes the commonsensical hypothesis that resource scarcity causes a large allocation of time and effort to appropriative competition. Our main innovation is to model explicitly the positive intertemporal effect of consumption on the probability of survival. The critical assumption is that this effect becomes stronger as resources become scarcer. We also show that anticipated future resource abundance increases the incremental value of survival and, consequently, amplifies the current allocation of time and effort to appropriative competition. Interestingly, if resources are currently scarce, then larger anticipated future abundance can cause a big enough increase in the time and effort allocated to appropriative competition to result in a decrease in the sum of current and expected future utility, a “paradox of anticipated abundance”.