行政组织边界理论基础上的我国农业行政执法体制改革理论模型研究

农业行政执法正逐步成为一项重要的农业行政职能 ,农业行政综合执法是我国农业行政执法体制改革中产生的新生事物 ,在实践中受到各方利益群体的质疑。本文以我国行政体制改革是行政边界和行政组织边界的双重边界重构为理论基础 ,研究归纳出我国农业行政执法的三种理论模型 ,并阐述了模型形成的依据和模型的替代顺序 ,认为综合执法是我国现阶段提高农业行政执法效率切实可行的选择 ,从长远来看也可能是一种过渡形式。     

Impact of legislation requiring moped and motorbike riders to wear helmets

In 1992, a package of measures was adopted by the city of Barcelona to obligate riders of motorcycles with a power capacity inferior to 125 cc to use helmets, until then only compulsory for larger motorcycles. Interrupted time series analyses with the use of a control group is used to investigate the effect of these measures on the number of serious injuries and number of deaths. The results indicate a significant decrease in the number of serious cases in the treated group—smaller motorcycles and mopeds—a decrease which does not occur in the control group —larger motorcycles. The impact of the adopted measures is abrupt and permanent but the change in riders helmet wearing habits has not been influenced so much by the media campaign as by the coming into force of the legislation with the potential application of sanctions.     

The Granular Origins of Aggregate Fluctuations

This paper proposes that idiosyncratic firm‐level shocks can explain an important part of aggregate movements and provide a microfoundation for aggregate shocks. Existing research has focused on using aggregate shocks to explain business cycles, arguing that individual firm shocks average out in the aggregate. I show that this argument breaks down if the distribution of firm sizes is fat‐tailed, as documented empirically. The idiosyncratic movements of the largest 100 firms in the United States appear to explain about one‐third of variations in output growth. This “granular” hypothesis suggests new directions for macroeconomic research, in particular that macroeconomic questions can be clarified by looking at the behavior of large firms. This paper's ideas and analytical results may also be useful for thinking about the fluctuations of other economic aggregates, such as exports or the trade balance.     

Strategic Supply Function Competition With Private Information

A finite number of sellers (n) compete in schedules to supply an elastic demand. The cost of each seller is random, with common and private value components, and the seller receives a private signal about it. A Bayesian supply function equilibrium is characterized: The equilibrium is privately revealing and the incentives to rely on private signals are preserved. Supply functions are steeper with higher correlation among the cost parameters. For high (positive) correlation, supply functions are downward sloping, price is above the Cournot level, and as we approach the common value case, price tends to the collusive level. As correlation becomes maximally negative, we approach the competitive outcome. With positive correlation, private information coupled with strategic behavior induces additional distortionary market power above full information levels. Efficiency can be restored with appropriate subsidy schemes or with a precise enough public signal about the common value component. As the market grows large with the number of sellers, the equilibrium becomes price‐taking, bid shading is on the order of 1/n, and the order of magnitude of welfare losses is 1/n². The results extend to inelastic demand, demand uncertainty, and demand schedule competition. A range of applications in product and financial markets is presented.     

The Sichel model and the mixing and truncation order

The analysis of word frequency count data can be very useful in authorship attribution problems. Zero-truncated generalized inverse Gaussian–Poisson mixture models are very helpful in the analysis of these kinds of data because their model-mixing density estimates can be used as estimates of the density of the word frequencies of the vocabulary. It is found that this model provides excellent fits for the word frequency counts of very long texts, where the truncated inverse Gaussian–Poisson special case fails because it does not allow for the large degree of over-dispersion in the data. The role played by the three parameters of this truncated GIG-Poisson model is also explored. Our second goal is to compare the fit of the truncated GIG-Poisson mixture model with the fit of the model that results from switching the order of the mixing and truncation stages. A heuristic interpretation of the mixing distribution estimates obtained under this alternative GIG-truncated Poisson mixture model is also provided.     

Selecting significant effects in factorial designs: Lenth's method versus using negligible interactions

Among the many analytical techniques that have been published to analyze the significance of the effects in the absence of replications, two have emerged as the most widely used in text books as well as statistical software packages: The Lenth's method and the estimation of the variance of the effects from the values of those considered negligible. This article shows that neither is better than the other in all cases, and by analyzing the results obtained in a wide variety of situations it provides guidelines on when it is preferable to use one or the other technique.     

A breakpoint detection in the mean model with heterogeneous variance on fixed time intervals

Statistics and Computing - This work is motivated by an application for the homogenization of global navigation satellite system (GNSS)-derived integrated water vapour series. Indeed, these series...     

Social cohesion revisited: a new definition and how to characterize it

This paper provides a general overview on different perspectives and studies on social cohesion, offers a definition of social cohesion that is deeply rooted in current literature, and provides a framework that can be used to characterize social cohesion and help support resilient cities. The framework highlights the factors that play a substantial role in enabling social cohesion, and shows from which perspectives it can be fostered.     

Labour incorporation of young Southern European graduates in Mexico: the impact of the economic crisis

ABSTRACT

The 2008 economic crisis has had particularly negative effects on the youth labour market outcomes in Southern Europe. Thus, it is hardly surprising that many Southern European youngsters see migration as the only way to escape from under-employment and precariousness. In this context, the article studies the reasons for emigration to Mexico of a group of young graduates from Italy and Spain. The paper is based on 42 in-depth semi-structured interviews with young graduates, aged 29 years old or less on their arrival in Mexico. The article first explores the relevance of the economic crisis as the main reason behind the migration of this group. It is revealed that the interviewed graduates had a precarious labour incorporation back in their countries of origin, and migration appeared as a means to further their careers. Second, the paper analyses the interviewees’ labour incorporation in Mexico; in many cases this coincides with an extended university-work transition, since many of them had not secured full-time permanent jobs before their arrival in Mexico. Finally, the paper explores the interviewees’ future plans. These depend not only on their work experiences in Mexico but also on their degree of social and cultural integration in the host country.