Are the closed landfills recovered habitats for small rodents? A case study in a riparian site,Buenos Aires,Argentina

The establishment of landfills in urban areas leads to extensive disturbances. Their development after landfill closure depends on the characteristics of the soil cover, the surrounding communities and the dispersal of plants and animals. This study was carried out in a landfill closed in 2004, surrounded by an urban area, freshwater marshes and a riparian forest. The aim of this study was to determine the role that the closed landfill may play in maintaining rodent communities typical of this zone and its relation to characteristics of the sites. Four rodent and plant samplings were carried out from December 2005 to September 2006 at five sites inside the landfill: three filled cells and two areas of the riparian margin. We recorded a total of 433 individual rodents. The rodent community of the closed landfill included species typical of rural, riparian and rural habitats: Akodon azarae (358), Oligoryzomys flavescens (32), Deltamys kempi (14), Rattus rattus (14), Cavia aperea (11) and Scapteromys aquaticus (4). Rodent species composition varied among sites, but A. azarae was usually the dominant species. We found a rich rodent community mostly composed of wild species. The relictual riparian margin may have served as a major refuge for native rodent community while the landfill was in operation, and after closure it possibly acted as a source for some species to colonize the covered cells.     

SYSTEMIC AND IDIOSYNCRATIC SOVEREIGN DEBT CRISES

The theoretical literature on sovereign defaults has focused on adverse shocks to debtors' economies, suggesting that defaults are of an idiosyncratic nature. Still, sovereign debt crises are also of a systemic nature, clustered around panics in the financial center, such as the European Sovereign Debt Crisis in the aftermath of the US Subprime Crisis in 2008. Crises in the financial centers are rare disasters and, thus, their effects on the periphery can only be captured by examining long episodes. In this paper, we examine sovereign defaults from 1820 to the Great Depression, with a focus on Latin America. We find that 63% of the crises are of a systemic nature. These crises are different. Both the international collapse of liquidity and the growth slowdown in the financial centers are at their core. These global shocks trigger longer default spells and larger losses for investors.     

Social Movements and Patronage Politics: Processes of Demobilization and Dual Pressure

Why might social movements be highly contentious at one point in time and demobilize shortly after? Based on ethnographic fieldwork, this article examines the dynamics of demobilization of popular movements in a context of patronage politics. I argue that demobilization in these contexts results from relational processes creating a “dual pressure” stemming “from below” and “from above.” In social environments where patronage is pervasive, poor people develop survival strategies relying on clientelistic arrangements. They participate in a social movement organization (SMO) to voice their rights, but also to address pressing survival needs by gaining access to resources. These expectations of constituents create a pressure “from below” on leaders of an SMO, which respond by securing resources obtained through alliances with national political actors. In turn, these alliances create a pressure “from above,” because local leaders reciprocate this national support by eschewing the organization of collective actions. Drawing on data culled from 12 months of fieldwork on an Argentine peasant movement, this article inspects the interconnections between popular movements and patronage politics to refine our understanding of demobilization processes; contribute to discussions regarding the role of culture on contentious politics; and shed light on current demobilization trends in Latin America.     

Area under the ROC curve comparison in the presence of missing data

The area under the receiver operating characteristic (ROC) curve (AUC) is broadly accepted and often used as a diagnostic accuracy index. Moreover, the equality among the predictive capacity of two or more diagnostic systems is frequently checked from the comparison of their respective AUCs. In paired designs, this comparison is usually performed by using only the subjects who have collected all the necessary information, in the so-called available-case analysis. On the other hand, the presence of missing data is a frequent problem, especially in retrospective and observational studies. The loss of statistical power and the misuse of the available information (with the resulting ethical implications) are the main consequences. In this paper a non-parametric method is developed to exploit all available information. In order to approximate the distribution for the proposed statistic, the asymptotic distribution is computed and two different resampling plans are studied. In addition, the methodology is applied to a real-world medical problem. Finally, some technical issues are also reported in the Appendix.     

Segmentation in Low-Penetration and Low-Involvement Categories: An Application to Lottery Games

Market segmentation is accepted as a fundamental concept in marketing and several authors have recently proposed a segmentation model where personal and environmental variables intersect with each other to form motivating conditions that drive behavior and preferences. This model of segmentation has been applied to packaged goods. This paper extends this literature by proposing a segmentation model for low-penetration and low involvement (LP-LI) products. An application to the lottery games in Chile supports the proposed model. The results of the study show that in this type of products (LP-LI), the attitude towards the product category is the most important factor that distinguishes consumers from non consumers, and heavy users from light users, and consequently, a critical segmentation variable. In addition, a cluster analysis shows the existence of three segments: (1) the impulsive dreamers, who believe in chance, and in that lottery games can change their life, (2) the skeptical, that do not believe in chance, nor in that lottery games can change their life and (3) the willing, who value the benefits of playing.     

论卢梭的人类学原则

与将卢梭作为一位折中的思想家的印象相反,这篇论文试图重建他的人类学体系的核心。首先,讨论方法论的起点问题。第二,展开论述使自然得以在社会背景下作为一种理想运作所需的结构框架。最后,根据这种框架阐释卢梭的起源论述。这个过程使我解决了两个阐释难题,关于坏的起源的困境和人的自然孤独的问题。引入一个逻辑学上的双重概念来整合历史的和结构的要求,这个概念与卢梭思想中的自由和必然性相重叠。用这种照镜子的方式来组织我的论证,我把这项工作称作一篇随笔,因为它是在尽力思考卢梭为了写他所写的东西一定会想过什么。     

New Properties of the Kumaraswamy Distribution

The Kumaraswamy distribution is very similar to the Beta distribution but has the key advantage of a closed-form cumulative distribution function. This makes it much better suited than the Beta distribution for computation-intensive activities like simulation modeling and the estimation of models by simulation-based methods. However, in spite of the fact that the Kumaraswamy distribution was introduced in 1980, further theoretical research on the distribution was not developed until very recently (Garg, 2008 Garg , M. ( 2008 ). On distribution of order statistics from Kumaraswamy distribution . Kyunpook Mathemat. J. 48 : 411 – 417 .[Crossref] , [Google Scholar]; Jones, 2009 Jones , M. C. ( 2009 ). Kumaraswamy's distribution: A beta-type distribution with some tractability advantages . Statist. Methodol. 6 ( 1 ): 70 – 81 .[Crossref] , [Google Scholar]; Mitnik, 2009 Mitnik , P. ( 2009 ). The Kumaraswamy distribution: a median-dispersion re-parameterization for regression modeling and simulation-based estimation. Available at SSRN: http://ssrn.com/abstract=1231587 . [Google Scholar]; Nadarajah, 2008 Nadarajah , S. ( 2008 ). On the distribution of Kumaraswamy . J. Hydrol. 348 : 568 – 569 .[Crossref], [Web of Science ®] , [Google Scholar]). This article contributes to this recent research and: (a) shows that Kumaraswamy variables exhibit closeness under exponentiation and under linear transformation; (b) derives an expression for the moments of the general form of the distribution; (c) specifies some of the distribution's limiting distributions; and (d) introduces an analytical expression for the mean absolute deviation around the median as a function of the parameters of the distribution, and establishes some bounds for this dispersion measure and for the variance.