THREE ESSAYS ON CHILD HEALTH AND SKILL FORMATION

This dissertation attempts to add to the scholarly literature on parental investments in children. In particular, these essays study a number of ways in which children use their time, and the potential influence of such use of time on the development of cognitive and non-cognitive skills in school-age children in the U.S. and in India. The particular uses of time that this dissertation addresses include participation in lessons and sports, spending time with mothers, and spending time away from school to support family members. The key difficulty in identifying a causal impact of these choices arises from the possibility that a child's human capital acquisition decisions are made jointly with a variety of other decisions. To deal with potential endogeneity in these analyses, I employ a number of empirical techniques: individual fixed effects, sibling fixed effects, and instrumental variables. The first essay examines the impact of parental choices regarding extra-curricular activities on the health and skill acquisition outcomes of school-age children in the US. Using longitudinal time use data from the Child Development Supplement (CDS) of the PSID, I find reduced behavioral problems and enhanced positive development for children that engage in structured activity. Participation in lessons also significantly increases positive behavior and mathematics test scores. In the second essay, data on a panel of children aged five through eighteen from the NLSY-Child (1979) are analyzed to explore the effect of maternal employment on a child's mental health outcomes. Using fixed effects estimates, we find that mothers who spend more time at home have children with fewer emotional problems: they score lower on the behavioral problems index; they are also less likely to be frequently unhappy or depressed. In the final essay, cross-section data drawn from the 50th Round of National Sample Survey (NSS) from rural India are analyzed to explore the relationship between fertility and child labor. Our results indicate the possibility of a sibling subsidization effect: all else equal, a new child in the family results in increasing the probability of sending an oldest child in the age group 5-14 out to work by over 5 percent

Transition from inspiral to plunge for braneworld EMRI

In the present article, we discuss the late inspiral and then the transition regime to the plunge phase of a secondary, less massive compact object into a more massive braneworld black hole, in the context of an extreme-mass-ratio inspiral. We obtain the approximate expressions for fluxes due to slowly evolving constants of motion, such as the energy and the angular momentum, in the presence of the tidal charge inherited from the higher spacetime dimensions for an extreme-mass-ratio system. These expressions for fluxes are further used to introduce dissipative effects while modeling the inspiral to the plunge phase through the transition regime. Within our setup, we provide a qualitative understanding of how the additional tidal charge present in the braneworld scenario may affect the timescale of the late inspiral to the plunge, in particular, by enhancing the time scale of the transition regime. Finally, we provide an estimate for the tidal charge from the higher dimensions, using the observable aspects of the transition regime from the late inspiral to the plunge by the gravitational wave detectors.Comment: 22 pages, 2 figure

Grouping of large populations into few CTL immune ‘response-types’ from influenza H1N1 genome analysis

Despite extensive work on influenza, a number of questions still remain open about why individuals are differently susceptible to the disease and why only some strains lead to epidemics. Here we study the effect of human leukocyte antigen (HLA) genotype heterogeneity on possible cytotoxic T-lymphocyte (CTL) response to 186 influenza H1N1 genomes. To enable such analysis, we reconstruct HLA genotypes in different populations using a probabilistic method. We find that epidemic strains in general correlate with poor CTL response in populations. Our analysis shows that large populations can be classified into a small number of groups called response-types, specific to a given viral strain. Individuals of a response-type are expected to exhibit similar CTL responses. Extent of CTL responses varies significantly across different populations and increases with increase in genetic heterogeneity. Overall, our analysis presents a conceptual advance towards understanding how genetic heterogeneity influences disease susceptibility in individuals and in populations. We also obtain lists of top-ranking epitopes and proteins, ranked on the basis of conservation, antigenic cross-reactivity and population coverage, which provide ready short-lists for rational vaccine design. Our method is fairly generic and has the potential to be applied for studying other viruses