FPT-algorithms for some problems related to integer programming

This paper studies a new version of the location problem called the mixed center location problem. Let P be a set of n points in the plane. We first consider the mixed 2-center problem, where one of the centers must be in P, and we solve it in \(O(n^2\log n)\) time. Second, we consider the mixed k-center problem, where m of the centers are in P, and we solve it in \(O(n^{m+O(\sqrt{k-m})})\) time. Motivated by two practical constraints, we propose two variations of the problem. Third, we present a 2-approximation algorithm and three heuristics solving the mixed k-center problem (\(k>2\)).     

Climate change and population migration in Brazil’s Northeast: scenarios for 2025–2050

This research contributes to an understanding of the relationship between climate change, economic impacts and migration. We model the long-term relationship (up to 45 years of projection) between demographic dynamics—particularly migration—driven by changes in the performance of the economy due to climate changes in the Northeast region of Brazil. The region is of particular relevance to the study of climate change impacts given its large human population (28% of Brazil’s population) and high levels of impoverishment, having an extensive semi-dry area which will be severely impacted by growing temperatures. Ultimately, the integrated model generates state- and municipal-level migration scenarios based on climate change impacts on the primary economic sectors and their articulations with other sectors. Results suggest that the predicted climate changes will impact severely the agriculture sector in the region, acting as a potential migration push factor to other regions in the country. Finally, we discuss how the increased vulnerability of some groups, particularly migrants, can be factored into Brazilian public policy and planning.     

An Analysis of Student Satisfaction: Full-Time vs. Part-Time Students

This paper examines how full-time or part-time status affects students’ level of satisfaction with their degree programs. For our analysis, we obtained data from a survey of graduate students. The survey was conducted at a public university in Spain from 2001 to 2004. The decision to undertake paid employment while studying emerges as one of the key determinants of student satisfaction. In particular, our findings indicate that students who hold a part-time job while studying are more likely to express less satisfaction with their college experience.     

Class, gender and time poverty: a time-use analysis of British workers' free time resources

Free time, that is, the time that remains at one's own discretion after conducting daily work and personal care activities, has been previously recognized as a 'primary good' and an important welfare resource that provides opportunities for participation in social life and leisure. However, recent years have witnessed an increasing preoccupation with the phenomenon of time poverty, drawing attention to the distribution of free time and its relationship to structural and family circumstances. In this article we propose a novel approach to the measurement of time poverty and document its occurrence amongst British workers. In line with previous literature, a conceptualization of time poverty as a relative lack of free time resources vis-à-vis other members of the community is adopted. However, unlike previous empirical studies, we investigate the differential configuration of time poverty on weekdays and weekend days, alongside indicators of the quality of free time, taking into account insights from theoretical and empirical work within the field of the sociology of time. Our analysis of the 2000 UK Time Use Survey highlights class and gender inequalities that have been missed by previous measurement approaches and demonstrates that, overall, working women experience multiple and more severe free time constraints, which may constitute an additional barrier for their leisure and social participation.     

Household Saving Behavior and the Influence of Family-Owned Business

This study focused on the lifecycle income objective of business-owning (farm and nonfarm) households. We hypothesized that the complex relationship between household and business management decisions had the potential to challenge predictions from standard household savings theory. Specifically, we tested for differences in saving behavior of these entrepreneurial households relative to the average US household. A limited dependent variable model was performed, keying in on the saving behavior and ability of household respondents in the Survey of Consumer Finances for 2007. The estimation results indicated that, along with standard demographic influences of savings models, households owning a farm or nonfarm business had a significantly higher likelihood of maintaining private saving in a given year. Our results highlight the necessity for future research on household saving behavior to account for the differing objectives and choice sets faced by households that own businesses when conducting analyses of household saving.     

Work and breastfeeding decisions are jointly determined for higher socioeconomic status US mothers

We study postpartum decisions about paid work and breastfeeding using a simultaneous equations model. For our sample of higher socioeconomic status mothers, we find a joint decision process for three sets of decisions modeled: work leave duration and duration of any, as well as of exclusive, breastfeeding, and daily work hours and daily breastfeedings at infant age 3 months. We find that returning to paid work 1 week earlier reduces any breastfeeding duration by about two-thirds of a week while extending breastfeeding by a week delays work participation by about one-third of a week. We find larger elasticities for decisions involving daily work hours and number of breastfeedings at 3 months than for work leave duration and any breastfeeding duration and the smallest elasticities for duration of exclusive breastfeeding and work leave. This marks the first study to find a joint decision-making process for postpartum work and breastfeeding decisions and suggests that, in addition to increased leave impacting breastfeeding behaviors, successful breastfeeding promotion policies can have nontrivial impacts on the US labor market.     

The influence of FDA advisory information and black box warnings on individual use of prescription antidepressants

We examine how use of antidepressant medications is influenced by Food and Drug Administration (FDA) warnings about the increased risk of suicidality associated with pediatric antidepressant use. With individual-level data on antidepressant use from the Medical Expenditure Panel Survey, we consider whether consumer responses to FDA warnings differ among targeted (children) and non-targeted (adult) age-groups. Because the warning labels specifically mentioned new users, we examine separately the effects of the warnings on initiations of antidepressant therapy and on continued use of antidepressants. We find evidence consistent with reduced initiation of antidepressant use among the intended population of children, and that usage among children with more highly educated parents responded earlier to FDA information. However, we also find spillover effects of reduced initiation among the non-targeted population of adults. Overall, our results indicate that the FDA warning may have led consumers to perceive risks beyond those specifically mentioned.     

Changing Trends of Mothers’ Active and Passive Childcare Times

This paper explores how mothers’ allocation of types of time with children and the determinants of this allocation have changed during 1981–1997 in the United States, using Time Use Longitudinal Panel Study and Family Interaction, Social Capital and Trends in Time Use. Data reveal that active time with children has increased for the case of educated working mothers with young children. Estimations also provide evidence that although different uses of time are substitutes; active time is less sensitive than passive. Moreover, the relationship between active and passive time with children has changed over time.