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.     

Prevalence and Correlates of Sex Exchange Among a Nationally Representative Sample of Adolescents and Young Adults

The present study examines prevalence and correlates of exchanging sex for drugs, money, food shelter, or other favors (sex exchange) among a nationally representative sample of youth and young adults. Adolescents and young adults (n = 11,620, 53% female, 47% male) from the National Longitudinal Study of Adolescent Health were used for the current sample. Participants completed in-home interviews at both waves. Results revealed that sex exchange was reported by 4.9% (n = 569) of the population in wave 2 or wave 3, and 4.6% (n = 26) of those who exchanged sex did so at both waves. More males reported exchanging sex than females (n = 332 versus n = 237). Respondents who reported child sexual abuse were more likely to exchange sex (95% CI 2.51–4.28, p < .05) than respondents who reported any other form of child abuse. Both males and females who engaged in sex exchange were at greater risk for sexually transmitted infections; however, the odds of ever exchanging sex were highest among males who ever had gonorrhea (OR = 6.2; 95% CI 3.75–10.3). Although sex exchange has been studied extensively among homeless and runaway youth, the current study reveals sex exchange also occurs in the general population.     

Promises and Pitfalls of Using Digital Traces for Demographic Research

The digital traces that we leave online are increasingly fruitful sources of data for social scientists, including those interested in demographic research. The collection and use of digital data also presents numerous statistical, computational, and ethical challenges, motivating the development of new research approaches to address these burgeoning issues. In this article, we argue that researchers with formal training in demography—those who have a history of developing innovative approaches to using challenging data—are well positioned to contribute to this area of work. We discuss the benefits and challenges of using digital trace data for social and demographic research, and we review examples of current demographic literature that creatively use digital trace data to study processes related to fertility, mortality, and migration. Focusing on Facebook data for advertisers—a novel “digital census” that has largely been untapped by demographers—we provide illustrative and empirical examples of how demographic researchers can manage issues such as bias and representation when using digital trace data. We conclude by offering our perspective on the road ahead regarding demography and its role in the data revolution.     

Labor Migration between Developing Countries: The Case of Paraguay and Argentina1

Despite the historical and numerical importance of international migration between Paraguay and Argentina, the socioeconomic forces affecting the dynamics of the flow remain largely unexplored. This article contributes to the understanding of migration movements between the Latin American countries by analyzing patterns of labor migration from two Paraguayan communities to Argentina. The analysis separates the process of migration into four segments representing different migration decisions that Paraguayan men face throughout their life course: first trip, first return, recurrent trips, and duration of additional trips. Results confirm that Paraguayan migration to Argentina is closely related to individual characteristics and wealth, the extent of migrant networks and experience, and changes in macroeconomic conditions. The relative importance of these factors on migration varies depending on the aspect of migration under consideration. More generally, the analysis shows that unlike migration between Mexico and the United States, Paraguayan migrants to Argentina tend to be positively selected with respect to educational attainment and skills. This reflects the higher transferability of skills between the two countries and the absence of large urban centers attracting internal migrants in Paraguay. In addition, results show that migration between Paraguay and Argentina is very responsive to fluctuations in macroeconomic conditions, particularly income differentials and peso over‐valuation. Government policies oriented towards the regulation of migration flows in the Southern Cone should pay closer attention to the impact of macroeconomic fluctuations on migration decisions, especially in the context of the Mercosur agreement.     

The effect of artificial light on bat richness and nocturnal soundscapes along an urbanization gradient in an arid landscape of central Peru

Urbanization usually reduces bat richness; however, the presence of green areas within cities and peripheral rural areas in arid ecosystems may provide microhabitats for some species. Light pollution is a major feature of urbanization, but its impact on bat behavior appears to be species-specific and previous studies have documented contrasting responses. Moreover, the effect of urbanization on bat species has been poorly studied in arid regions. We assessed the effect of artificial night light intensity (as a proxy of urbanization) on both bat occupancy and the acoustic space used (ASU) in an urbanization gradient in Peruvian central coast, based on passive acoustic recorders. We collected 26,169 recordings from 19 sites which resulted in 579 independent detections of 15 bat species. Variation in both ASU and species richness was best explained by artificial night light intensity. Species-specific effects of the artificial night light intensity based on a multi-species occupancy modeling showed that this covariate had a negative effect on occupancy for most of the bat species (12 species). ASU and both observed and posterior bat species richness were positively correlated, suggesting that ASU can be used as a proxy of bat richness. This study provides evidence that both bat richness and occupancy decrease with artificial light intensity; nevertheless, eight species used urban areas, similar to results found in other cities around the world.

     

Properties and applications of the Poisson-reciprocal inverse Gaussian distribution

The barely known continuous reciprocal inverse Gaussian distribution is used in this paper to introduce the Poisson-reciprocal inverse Gaussian discrete distribution. Several of its most relevant statistical properties are examined, some of them directly inherited from the reciprocal of the inverse Gaussian distribution. Furthermore, a mixed Poisson regression model that uses the reciprocal inverse Gaussian as mixing distribution is presented. Parameters estimation in this regression model is performed via an EM type algorithm. In light of the numerical results displayed in the paper, the distributions introduced in this work are competitive with the classical negative binomial and Poisson-inverse Gaussian distributions.     

Fast and exact simulation of Gaussian random fields defined on the sphere cross time

Statistics and Computing - We provide a method for fast and exact simulation of Gaussian random fields on the sphere having isotropic covariance functions. The method proposed is then extended to...     

Acculturation, gender stereotypes, and attitudes about dating violence among Latino youth

This study examined the relationship between personal characteristics (gender, acculturation, belief in gender stereotypes, recent dating experiences), and attitudes and knowledge about dating violence in urban Latino youth (N = 678). All participants completed self-administered surveys at school. Relative to girls, boys held more problematic (proviolence) attitudes about dating violence and reported less knowledge about dating violence and its consequences. Teens who were more traditional (less acculturated), those who endorsed gender stereotypes, and those who reported recent fearful dating experiences tended to report less knowledge about abuse and lower endorsement of nonviolent attitudes. Multivariate analyses revealed that all four personal variables predicted dating violence knowledge. By contrast, attitudes were predicted by endorsement of gender stereotypes only, or gender stereotypes and gender. Implications for dating violence interventions and future directions for research are explored.     

Privacy,data protection and emerging sciences and technologies: towards a common framework

Privacy is an important fundamental human right. It underpins human dignity and other values such as freedom of association and freedom of speech. However, privacy is being challenged in the networked society. The use of new technologies undermines this right because it facilitates the collection, storage, processing and combination of personal data by security agencies and businesses. This research note presents the background and agenda of the recently-commenced research project PRESCIENT, which aims at reconceptualizing the concept of privacy and developing means for the assessment of privacy impacts.