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Microeconometrics researchers have increasingly realized the essential need to account for any within-group dependence in estimating standard errors of regression parameter estimates. The typical preferred solution is to calculate cluster-robust or sandwich standard errors that permit quite general heteroskedasticity and within-cluster error correlation,(More)
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This study considers sibling differences in child labor in Nepal. The data are consistent with a model where parents care equally for all children but siblings differ in comparative advantage in household production, although parental preferences and credit constraints could also be important. Girls, especially older girls, tend to work more than their(More)
Lleras-Muney, and participants in Princeton's Public Finance Working Group for useful comments, and Cynthia Cohen for assistance in the preparation of the manuscript. The views expressed herein are those of the authors and not necessarily those of the National Bureau of Economic Research. All rights reserved. Short sections of text not to exceed two(More)
A growing literature documents cyclical movements in mortality and health. We examine this pattern more closely and attempt to identify the mechanisms behind it. Specifically, we distinguish between mechanisms that rely on fluctuations in own employment or time use and those involving factors that are external to the individual. Our investigation suggests(More)
Development of nonviral gene transfer methods would be a valuable addition to the gene-therapy armamentarium, particularly for localized targeting of specific tissue volumes. Ultrasound can produce a variety of nonthermal bioeffects via acoustic cavitation including DNA delivery. Cavitation bubbles may induce cell death or transient membrane(More)