Why is child malnutrition lower in urban than rural areas?

"While ample evidence documents that urban children generally have better nutritional status than their rural counterparts, recent research suggests that urban malnutrition is on the rise. The environment, choices, and opportunities of urbanites differ greatly from those of rural dwellers' from employment conditions to social and family networks to access to health care and other services. Given these differences, understanding the relative importance of the various determinants of child malnutrition in urban and rural areas and especially whether they differ is key to designing context-relevant, effective program and policy responses for stemming malnutrition. This study uses Demographic and Health Survey data from 36 developing countries to address the question of whether the socioeconomic determinants of child nutritional status differ across urban and rural areas. The purpose is to answer the broader question of why child malnutrition rates are lower in urban areas. The socioeconomic determinants examined are women's education, women's status, access to safe water and sanitation, and household economic status. The analysis finds little evidence of differences in the nature of the socioeconomic determinants or in the strength of their associations with child nutritional status across urban and rural areas. As expected, however, it documents marked differences in the levels of these determinants in favor of urban areas. Large gaps in favor of urban areas are also found in the levels of key proximate determinants of child nutritional status, especially maternal prenatal and birthing care, quality of complementary feeding, and immunization of children. The conclusion is that better nutritional status of urban children is probably due to the cumulative effect of a series of more favorable socioeconomic conditions, which, in turn, seems to lead to better caring practices for children and their mothers. Given that the nature of the determinants of child nutritional status is largely the same across urban and rural areas, the same program and policy framework can be used to stem malnutrition in both. Efforts to alleviate the most critical socioeconomic constraints specific to the different environments should continue to be prioritized." Authors' Abstractmalnutrition ,Demographic and Health Survey ,

Why is child malnutrition lower in urban than rural areas?

"While ample evidence documents that urban children generally have better nutritional status than their rural counterparts, recent research suggests that urban malnutrition is on the rise. The environment, choices, and opportunities of urbanites differ greatly from those of rural dwellers' from employment conditions to social and family networks to access to health care and other services. Given these differences, understanding the relative importance of the various determinants of child malnutrition in urban and rural areas and especially whether they differ is key to designing context-relevant, effective program and policy responses for stemming malnutrition. This study uses Demographic and Health Survey data from 36 developing countries to address the question of whether the socioeconomic determinants of child nutritional status differ across urban and rural areas. The purpose is to answer the broader question of why child malnutrition rates are lower in urban areas. The socioeconomic determinants examined are women's education, women's status, access to safe water and sanitation, and household economic status. The analysis finds little evidence of differences in the nature of the socioeconomic determinants or in the strength of their associations with child nutritional status across urban and rural areas. As expected, however, it documents marked differences in the levels of these determinants in favor of urban areas. Large gaps in favor of urban areas are also found in the levels of key proximate determinants of child nutritional status, especially maternal prenatal and birthing care, quality of complementary feeding, and immunization of children. The conclusion is that better nutritional status of urban children is probably due to the cumulative effect of a series of more favorable socioeconomic conditions, which, in turn, seems to lead to better caring practices for children and their mothers. Given that the nature of the determinants of child nutritional status is largely the same across urban and rural areas, the same program and policy framework can be used to stem malnutrition in both. Efforts to alleviate the most critical socioeconomic constraints specific to the different environments should continue to be prioritized." Authors' Abstractmalnutrition ,Demographic and Health Survey ,

Splitting between Bright and Dark excitons in Transition Metal Dichalcogenide Monolayers

The optical properties of transition metal dichalcogenide monolayers such as the two-dimensional semiconductors MoS$_2$ and WSe$_2$ are dominated by excitons, Coulomb bound electron-hole pairs. The light emission yield depends on whether the electron-hole transitions are optically allowed (bright) or forbidden (dark). By solving the Bethe Salpeter Equation on top of $GW$ wave functions in density functional theory calculations, we determine the sign and amplitude of the splitting between bright and dark exciton states. We evaluate the influence of the spin-orbit coupling on the optical spectra and clearly demonstrate the strong impact of the intra-valley Coulomb exchange term on the dark-bright exciton fine structure splitting.Comment: 6 pages, 2 figure

Tidal Disruption of Protoclusters in Giant Molecular Clouds

We study the collapse of protoclusters within a giant molecular cloud (GMC) to determine the conditions under which collapse is significantly disrupted. Motivated by observations of star forming regions which exhibit flattened cloud structures, this study considers collapsing protoclusters with disk geometries. The collapse of a 10^3 Msun protocluster initially a distance of 2-10 pc from a 10^3 - 10^6 Msun point mass is numerically calculated. Simulations with zero initial relative velocity between the two are completed as well as simulations with relative velocities consistent with those observed in GMCs. The results allow us to define the conditions under which it is safe to assume protocluster collapse proceeds as if in isolation. For instance, we find the collapse of a 10^3 Msun protocluster will be significantly disrupted if it is within 2-4 pc of a 10^4 Msun point mass. Thus, the collapse of a 10^3 Msun protocluster can be considered to proceed as if in isolation if it is more than ~ 4 pc away from a 10^4 Msun compact object. In addition, in no portion of the sampled parameter space does the gravitational interaction between the protocluster disk and the massive particle significantly disperse the disk into the background GMC. We discuss the distribution of clusters of young stellar objects within the Perseus and Mon R2 star forming regions, which are consistent with the results of our simulations and the limitations of our results in gas dominated regions such as the Orion cloud.Comment: 12 pages, 6 figures, Accepted for publication in Ap

Impact of heavy hole-light hole coupling on optical selection rules in GaAs quantum dots

We report strong heavy hole-light mixing in GaAs quantum dots grown by droplet epitaxy. Using the neutral and charged exciton emission as a monitor we observe the direct consequence of quantum dot symmetry reduction in this strain free system. By fitting the polar diagram of the emission with simple analytical expressions obtained from k$\cdot$p theory we are able to extract the mixing that arises from the heavy-light hole coupling due to the geometrical asymmetry of the quantum dot.Comment: 4 pages, 2 figure

Giant spin-dependent photo-conductivity in GaAsN dilute nitride semiconductor

A theoretical and experimental study of the spin-dependent photoconductivity in dilute Nitride GaAsN is presented. The non linear transport model we develop here is based on the rate equations for electrons, holes, deep paramagnetic and non paramagnetic centers both under CW and pulsed optical excitation. Emphasis is given to the effect of the competition between paramagnetic centers and non paramagnetic centers which allows us to reproduce the measured characteristics of the spin-dependent recombination power dependence. Particular attention is paid to the role of an external magnetic field in Voigt geometry. The photoconductivity exhibits a Hanle-type curve whereas the spin polarization of electrons shows two superimposed Lorentzian curves with different widths, respectively related to the recombination of free and trapped electrons. The model is capable of reproducing qualitatively and quantitatively the most important features of photoluminescence and photocurrent experiments and is helpful in providing insight on the various mechanisms involved in the electron spin polarization and filtering in GaAsN semiconductors.Comment: 10 pages, 5 figure

Development and evaluation of lessons for class and group situations in grade one

Thesis (Ed.M.)--Boston Universit

Bunching visibility for correlated photons from single GaAs quantum dots

We study photon bunching phenomena associated with biexciton-exciton cascade in single GaAs self-assembled quantum dots. Experiments carried out with a pulsed excitation source show that significant bunching is only detectable at very low excitation, where the typical intensity of photon streams is less than the half of their saturation value. Our findings are qualitatively understood with a model which accounts for Poissonian statistics in the number of excitons, predicting the height of a bunching peak being determined by the inverse of probability of finding more than one exciton.Comment: 6 pages, 6 figs to appear in Phys. Rev.

Maladie mentale et stigmatisation ou Comment on devient un malade mental pour la vie

La perspective sociologique telle que présentée ici en relation avec la santé et/ou la maladie mentale est basée sur une approche interactionniste du phénomène. En effet, la société est composée d'un ensemble de normes et de valeurs, partagées par la majorité des personnes au sein d'une même culture à une époque donnée. Ces normes dont l'apprentissage commence dès la naissance de l'individu, sont issues de la génération précédente et ainsi transmises de génération en génération. Normes et valeurs constituent le tissu social, fondement de notre vie en commun. Il s'agit d'une vision de la société centrée principalement sur les rapports entre les individus et la société, et entre les individus et les institutions, ces rapports étant définis par un ensemble d'interdépendance psychologique et sociale.In this article mental illness is presented in a sociological perspective, giving prominence to social-interaction factors which, in many cases, are responsable for the permanence of this type of illness. Its thereotical base comes !form the psychology of social-interaction developped by G.H. Mead and his disciples. This perspective defines the social human being as derived from successive interactions, beginning, at birth, with maternal contacts and extending progressively to the entirety of the members of the community of which the individual is a part. This interactional network is comprised of messages, of responses, and of expectations which make up the norms and values which in turn from the basis for the distribution of roles and statuses- From these roles and statuses derive the behaviours acceptable to a given collectivity. Among other theoretical developments, interactionist sociology gave birth to formulations on deviance which became known, in american terminology as "labelling theory". In the case of mental illness many sociologists interested in the phenomenon have studied it, using the framework elaborated by the proponents of this approach to deviance. Thus, rather than considering the deviant as abnormal in himself, deviance is viewed as a process; that is, as the result of a series of interactions confronting the individual who is not, or does not behave like the collectivity as a whole and the milieu in which he lives. When the reaction of the entourage is negative, the so-called deviant is subjected to sanctions such as avoidance, rejection, exclusion, confinement, etc... This process terminates generally in stigmatization which wraps the deviant in a label from which he will probably never free himself. The studies cited demonstrate this interactional process at different stages of mental illness, these being; d) at the point of medical diagnosis, b) during hospitalisation, c) on leaving We psychiatric institution, d) and after the return to society. The conclusion leads to an appreciation of the drama experienced by psychiatric ex-patients, for most of whom the label "mentally ill" constitutes an apparently irreversible stigmatization