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.     

The relationship between Civil Unions and fertility in France: Preliminary evidence

This paper explores the relationship between fertility and the introduction of new laws regulating cohabitation, in a context of low fertility and high out of wedlock childbearing. We show that in France, while fertility and marriage rates moved closely together before 1999, since the introduction (in 1999) of the “Pacte Civil de Solidarité” (PACS)—a cohabitation contract less binding than marriage—this relationship is much weaker. Surprisingly, legal unions (defined as marriage plus PACS) and fertility continue to move together after this date. We provide evidence of the relationship between the introduction of PACS and fertility, utilizing the regional variation in the number of PACS per woman (PACS intensity) and the differences in fertility before and after 1999. We show that French Departments with high PACS intensity did not show a different trend in fertility before 1999 than those with low PACS intensity (excluding Metropolitan Paris). However, they did experience an increase in their fertility levels after the introduction of PACS. This suggests the need to collect better and more detailed data, in order to assess whether the recent increases in French fertility can be partially explained by the availability of PACS.     

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.     

Using satellite imagery to measure the relationship between air quality and infant mortality: an empirical study for Mexico

This research uses a unique dataset that provides relatively inexpensive measures of air quality at detailed geography. The analytical focus is the relationship, in Mexico, between Aerosol Optical Depth (AOD, a measure of air quality obtained from satellite imagery) and infant mortality due to respiratory diseases from January, 2001 through December, 2006. The results contribute to existing literature on the relationship between air pollution and health outcomes by examining, for the first time, the relationship between these variables for the entire land area of Mexico, for most of which no ground measures of pollution concentrations exist. Substantive results suggest that changes in AOD have a significant impact on infant mortality due to respiratory diseases in municipalities in the three highest AOD quartiles in the country, providing evidence that air pollution’s adverse effects, although nonlinear, are not only present in large cities, but also in lower pollution settings which lack ground measures of pollution. Methodologically, it is argued that satellite-based imagery can be a valuable source of information for both researchers and policy makers when examining the consequences of pollution and/or the effectiveness of pollution-control mechanisms.     

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.     

A new discrete distribution: properties and applications in medical care

This paper proposes a simple and flexible count data regression model which is able to incorporate overdispersion (the variance is greater than the mean) and which can be considered a competitor to the Poisson model. As is well known, this classical model imposes the restriction that the conditional mean of each count variable must equal the conditional variance. Nevertheless, for the common case of well-dispersed counts the Poisson regression may not be appropriate, while the count regression model proposed here is potentially useful. We consider an application to model counts of medical care utilization by the elderly in the USA using a well-known data set from the National Medical Expenditure Survey (1987), where the dependent variable is the number of stays after hospital admission, and where 10 explanatory variables are analysed.     

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.     

Biowarfare as a biopolitical icon

Nuclear warfare threat has been one of the main driver for cultural, political, economical and social changes in the late twentieth century, biological warfare threat is about to take it over. However, while nuclear warfare was a concrete possibility, biological warfare is just an elusive risk. This paper will explore some reasons for this apparent inconsistency by discussing biowarfare from a symbolic point of view, looking for its inner meanings and philosophical implications.

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Zusammenfassung  Der drohende Atomkrieg war eine der Hauptantriebe kulturellen, politischen, wirtschaftlichen und gesellschaftlichen Wandels im späten 20. Jahrhundert. Jetzt ist die Gefahr biologischer Kriege im Begriff, diese Rolle zu übernehmen. Während der Atomkrieg jedoch eine konkrete Möglichkeit war, ist der Biokrieg nur ein kaum greifbares Risiko. In diesem Beitrag untersuchen wir einige der Gründe für diesen offenbaren Widersinn, indem wir biologische Kriegführung von einem symbolischen Standpunkt aus diskutieren und nach ihren inneren Bedeutungen und philosophischen Implikationen suchen.

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Résumé  La menace de guerre atomique a été l’un des moteurs principaux des changements culturels, politiques, économiques et sociaux dans la deuxième moitié du XX ^e siècle, la menace de guerre biologique est en passe de reprendre ce rôle. Toutefois, tandis que la guerre nucléaire était une possibilité concrète, la guerre biologique est un risque peu tangible. Le présent article explore les raisons de la contradiction apparente qui nous fait considérer la guerre biologique d’un point de vue symbolique et rechercher ses significations intérieures et ses implications philosophiques.

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