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Felix Almaraz, Author and Teacher, "The Tragic Calvalier."(photograph)
No full textPhotograph of Felix Almaraz, Author and Teacher, "The Tragic Calvalier."
Stable and Robust Sampling Strategies for Compressive Imaging
No full textIn many signal processing applications, one wishes to acquire images that are sparse in transform domains such as spatial finite differences or wavelets using frequency domain samples. For such applications, overwhelming empirical evidence suggests that superior image reconstruction can be obtained through variable density sampling strategies that concentrate on lower frequencies. The wavelet and Fourier transform domains are not incoherent because low-order wavelets and low-order frequencies are correlated, so compressive sensing theory does not immediately imply sampling strategies and reconstruction guarantees. In this paper, we turn to a more refined notion of coherence-the so-called local coherence-measuring for each sensing vector separately how correlated it is to the sparsity basis. For Fourier measurements and Haar wavelet sparsity, the local coherence can be controlled and bounded explicitly, so for matrices comprised of frequencies sampled from a suitable inverse square power-law density, we can prove the restricted isometry property with near-optimal embedding dimensions. Consequently, the variable-density sampling strategy we provide allows for image reconstructions that are stable to sparsity defects and robust to measurement noise. Our results cover both reconstruction by l(1)-minimization and total variation minimization. The local coherence framework developed in this paper should be of independent interest, as it implies that for optimal sparse recovery results, it suffices to have bounded average coherence from sensing basis to sparsity basis-as opposed to bounded maximal coherence-as long as the sampling strategy is adapted accordingly
Lower bounds for the error decay incurred by coarse quantization schemes
No full textAbstractSeveral analog-to-digital conversion methods for bandlimited signals used in applications, such as ΣΔ quantization schemes, employ coarse quantization coupled with oversampling. The standard mathematical model for the error accrued from such methods measures the performance of a given scheme by the rate at which the associated reconstruction error decays as a function of the oversampling ratio λ. It was recently shown that exponential accuracy of the form O(2−αλ) can be achieved by appropriate one-bit Sigma–Delta modulation schemes. However, the best known achievable rate constants α in this setting differ significantly from the general information theoretic lower bound. In this paper, we provide the first lower bound specific to coarse quantization, thus narrowing the gap between existing upper and lower bounds. In particular, our results imply a quantitative correspondence between the maximal signal amplitude and the best possible error decay rate. Our method draws from the theory of large deviations
Replication data for: The vagaries of the sea: evidence on the real effects of money from maritime disasters in the Spanish Empire
No full textReview of Economics and Statistics: Forthcomin
Parents’ assets and child marriage: are mother’s assets more protective than father’s assets?
No full textChild marriage places girls at an increased risk for dropping out of school early, sexually transmitted infections, teenage childbirth, and accompanying childbirth complications, including maternal mortality. The determinants of child marriage are not clearly understood, which hinders efforts to mount effective interventions. This study examined the link between economic resources and child marriage by investigating whether maternal and paternal asset ownership were longitudinally associated with daughters’ child marriage in Ethiopia. Drawing upon household bargaining theory, it was hypothesized that maternal assets would be more protective of daughters’ child marriage than paternal assets. Data for 4,293 girls from the nationally representative Ethiopia Socioeconomic Survey, fielded in 2011 and 2014, were employed. Logistic regression and instrumental variable analyses were used to examine the relationship between transition into child marriage during the study period and maternal and paternal assets, controlling for child-, family-, and community-level characteristics. Results show that a one standard deviation increase in mother’s assets was associated with 37–53% lower odds of daughter’s child marriage whereas a one standard deviation increase in paternal asset holdings was associated with 0–37% higher odds of daughter’s child marriage. Effects were strongest in regions where the dominant mode of marriage payments is bride price. These results suggest that the link between economic resources and child marriage depends on the gender of the parent who owns the resources. This study also highlights the interconnectedness of two targets of the gender equality Sustainable Development Goal—improvement of women’s ownership of assets and the elimination of child marriage—and suggests that the realization of one gender equality target could have implications for other targets.Peer reviewe
Disability among children of immigrants from India and China: is there excess disability among girls?
No full textWe investigate whether there is excess morbidity among daughters of Indian or Chinese immigrants in the US by studying the prevalence of disability among children. We use data from the 2012–14 American Community Surveys on approximately 20,000 US-born children of Indian and Chinese immigrants. Children of US natives are used as a comparison group to account for innate differences in disability between the sexes. Results indicate that there is excess disability among daughters compared with sons among children of Chinese immigrants and children of immigrants from northern or western Indian states; this excess disability declines with younger age at arrival or longer exposure to the host country. Analysis using children of Filipino immigrants as an alternative comparison group yields similar excess disability rates for females.Peer reviewe
Effect of Food Subsidies on Micronutrient Consumption
No full textIn this article, we study the effect of an exogenous increase in wheat and rice price subsidy to poor families resulting from a targeted food price subsidy program in India called the Targeted Public Distribution System (TPDS) on micronutrient intake in low-income families. Descriptive results show that wheat and rice have one of the lowest micronutrient density scores, suggesting that these are poor suppliers of micronutrients. Empirical analysis suggests that the increase in subsidy amount of Rs. 15-18 resulting from the TPDS expansion lowered calcium intake by 12-14 percent and had negligible to small (often negative) effects on the consumption of most micronutrients.Peer reviewe
Sex composition of children and spousal sexual violence in sub-Saharan Africa
No full textObjective
In societies with a cultural preference for sons over daughters, women who do not bear sons may be at increased risk for spousal violence. This study examined whether women with daughters only are at an elevated risk for spousal sexual violence compared to women with sons only in sub-Saharan Africa. The study tested the hypothesis that the association between sex composition of children and spousal sexual violence would be observed only in large families.
Methods
Data were from the most recent (as at February, 2016) Demographic and Health Surveys conducted in 22 sub-Saharan African countries for 37,915 women. Odds ratios comparing experience of spousal sexual violence of women with sons only to those with daughters only were estimated, separately for women with three or fewer children and those with four or more children, controlling for age, age at first cohabitation, age at first birth, educational attainment, urban residence, and household wealth.
Results
Having daughters only was associated with a greater likelihood of spousal sexual violence among women with many children (adjusted odds ratio [AOR] = 1.53; 95% CI = 1.02–2.30) but not among those with few children (AOR = 0.92; 95% CI = 0.82–1.04).
Conclusions for practice
A higher risk of sexual violence for women without sons suggests that son preference may have implications on women’s health and wellbeing. Efforts to further understand and address increased risk of sexual violence for women without sons should consider son preference and intra-couple conflict concerning fertility intentions.Peer reviewe
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