STARRY: Analytic Occultation Light Curves

We derive analytic, closed form, numerically stable solutions for the total flux received from a spherical planet, moon or star during an occultation if the specific intensity map of the body is expressed as a sum of spherical harmonics. Our expressions are valid to arbitrary degree and may be computed recursively for speed. The formalism we develop here applies to the computation of stellar transit light curves, planetary secondary eclipse light curves, and planet-planet/planet-moon occultation light curves, as well as thermal (rotational) phase curves. In this paper we also introduce STARRY, an open-source package written in C++ and wrapped in Python that computes these light curves. The algorithm in STARRY is six orders of magnitude faster than direct numerical integration and several orders of magnitude more precise. STARRY also computes analytic derivatives of the light curves with respect to all input parameters for use in gradient-based optimization and inference, such as Hamiltonian Monte Carlo (HMC), allowing users to quickly and efficiently fit observed light curves to infer properties of a celestial body's surface map.Comment: 55 pages, 20 figures. Accepted to the Astronomical Journal. Check out the code at https://github.com/rodluger/starr

Management of supernumerary testis: a rare case of polyorchidism in a 2-year-old boy

Polyorchidism is a rare congenital abnormality described as the presence of three or more testicles. We report the case of a 2-year-old boy with intermittent left-sided scrotal swelling and an ipsilateral undescended testis. During the operation, a left cryptorchid testis was found at the external ring, with further dissection revealing a second vas deferens attached to an additional intrascrotal testis. The cryptorchid testis was pexied in the left hemiscrotum with the second descended testis left in place. A review of the literature reveals over 150 cases of supernumeracy testis. Triorchidism is the most common form with the third testis typically located within the scrotal sac. Supernumeracy testis is frequently associated with undescended testis, testicular torsion, inguinal hernia, and hydrocele. Management is controversial with some advocating for orchidectomy due to concerns of malignancy. The family was educated about the risk for malignancy and the importance of regular follow-up and testicular self examination starting at puberty.Keywords: orchidectomy, orchidopexy, polyorchidism, supernumerary testi

Appraising Cross-National Income Inequality Databases: An Introduction

In response to a growing interest in comparing inequality levels and trends across countries, a number of cross-national inequality databases are now available. These databases differ considerably in purpose, coverage, data sources, inclusion and exclusion criteria, and quality of documentation. A special issue of the Journal of Economic Inequality, which this paper introduces, is devoted to an assessment of the merits and shortcomings of eight such databases. Five of these sets are microdata-based: CEPALSTAT, Income Distribution Database (IDD), LIS, PovcalNet, and Socio-Economic Database for Latin America and the Caribbean (SEDLAC). Two are based on secondary sources: "All the Ginis" (ATG) and the World Income Inequality Database (WIID); and one is generated entirely through multiple-imputation methods: the Standardized World Income Inequality Database (SWIID). Although there is much agreement across these databases, there is also a non-trivial share of country/year cells for which substantial discrepancies exist. In some cases, different databases would lead users to radically different conclusions about inequality dynamics in certain countries and periods. The methodological differences that lead to these discrepancies often appear to be driven by a fundamental trade-off between a wish for broader coverage on the one hand, and for greater comparability on the other. These differences across databases place considerable responsibility on both producers and users: on the former, to better document and explain their assumptions and procedures, and on the latter, to understand the data they are using, rather than merely taking them as true because available

Distributional effects of taxation in Latin America

This chapter analyzes the incidence on income distribution by a comprehensive array of direct and indirect taxes in ten Latin American countries circa 2018. The study finds that although there is a significant heterogeneity, the redistributive impact is equalizing for direct taxes and unequalizing for indirect taxes. Overall, redistribution through taxes, without accounting for spending effects and interactions, is slightly equalizing for some countries and unequalizing for others, but the burden on the poor is high and even higher than on the rich. This is mainly a consequence of the high share of indirect taxes in the tax structures, and of low personal income tax collection and coverage. The inclusion of the redistributive effect of the corporate income tax contributes to improve redistribution and accounts for better comparison with the redistributive impact in more developed countries, where dividends are taxed heavily with personal income taxes rather than corporate income taxes as in Latin America. High levels of evasion and informality make payroll taxes more regressive in integrated labor markets with high informality, but make indirect taxes less regressive, since the poor pay little or no indirect taxes on some of their purchases

Challenges to estimating vaccine impact using hospitalization data.

Because the real-world impact of new vaccines cannot be known before they are implemented in national programs, post-implementation studies at the population level are critical. Studies based on analysis of hospitalization rates of vaccine-preventable outcomes are typically used for this purpose. However, estimates of vaccine impact based on hospitalization data are particularly prone to confounding, as hospitalization rates are tightly linked to changes in the quality, access and use of the healthcare system, which often occur simultaneously with introduction of new vaccines. Here we illustrate how changes in healthcare delivery coincident with vaccine introduction can influence estimates of vaccine impact, using as an example reductions in infant pneumonia hospitalizations after introduction of the 10-valent pneumococcal conjugate vaccine (PCV10) in Brazil. To this end, we explore the effect of changes in several metrics of quality and access to public healthcare on trends in hospitalization rates before (2008-09) and after (2011-12) PCV10 introduction in 2010. Changes in infant pneumonia hospitalization rates following vaccine introduction were significantly associated with concomitant changes in hospital capacity and the fraction of the population using public hospitals. Importantly, reduction of pneumonia hospitalization rates after PCV10 were also associated with the expansion of outpatient services in several Brazilian states, falling more sharply where primary care coverage and the number of health units offering basic and emergency care increased more. We show that adjustments for unrelated (non-vaccine) trends commonly employed by impact studies, such as use of single control outcomes, are not always sufficient for accurate impact assessment. We discuss several ways to identify and overcome such biases, including sensitivity analyses using different denominators to calculate hospitalizations rates and methods that track changes in the outpatient setting. Employing these practices can improve the accuracy of vaccine impact estimates, particularly in evolving healthcare settings typical of low- and middle-income countries

Impact of Pneumococcal Conjugate Vaccines on Pneumonia Hospitalizations in High- and Low-Income Subpopulations in Brazil.

BackgroundPneumococcal conjugate vaccines (PCVs) are being used worldwide. A key question is whether the impact of PCVs on pneumonia is similar in low- and high-income populations. However, most low-income countries, where the burden of disease is greatest, lack reliable data that can be used to evaluate the impact. Data from middle-income countries that have both low- and high-income subpopulations can provide a proxy measure for the impact of the vaccine in low-income countries.MethodsWe evaluated the impact of PCV10 on hospitalizations for all-cause pneumonia in Brazil, a middle-income country with localities that span a broad range of human development index (HDI) levels. We used complementary time series and spatiotemporal methods (synthetic controls and hierarchical Bayesian spatial regression) to test whether the decline in pneumonia hospitalizations associated with vaccine introduction varied across the socioeconomic spectrum.ResultsWe found that the declines in all-cause pneumonia hospitalizations in children and young and middle-aged adults did not vary substantially across low and high HDI subpopulations. Moreover, the estimated declines seen in infants and young adults were associated with higher levels of uptake of the vaccine at a local level.ConclusionsThese results suggest that PCVs have an important impact on hospitalizations for all-cause pneumonia in both low- and high-income populations

Mixed-proxy extensions for the NVIDIA PTX memory consistency model

In recent years, there has been a trend towards the use of accelerators and architectural specialization to continue scaling performance in spite of a slowing of Moore's Law. GPUs have always relied on dedicated hardware for graphics workloads, but modern GPUs now also incorporate compute-domain accelerators such as NVIDIA's Tensor Cores for machine learning. For these accelerators to be successfully integrated into a general-purpose programming language such as C++ or CUDA, there must be a forward- and backward-compatible API for the functionality they provide. To the extent that all of these accelerators interact with program threads through memory, they should be incorporated into the GPU's memory consistency model. Unfortunately, the use of accelerators and/or special non-coherent paths into memory produces non-standard memory behavior that existing GPU memory models cannot capture. In this work, we describe the "proxy" extensions added to version 7.5 of NVIDIA's PTX ISA for GPUs. A proxy is an extra tag abstractly applied to every memory or fence operation. Proxies generalize the notion of address translation and specialized non-coherent cache hierarchies into an abstraction that cleanly describes the resulting non-standard behavior. The goal of proxies is to facilitate integration of these specialized memory accesses into the general-purpose PTX programming model in a fully composable manner. This paper characterizes the behaviors that proxies can capture, the microarchitectural intuition behind them, the necessary updates to the formal memory model, and the tooling that we built in order to ensure that the resulting model both is sound and meets the needs of business-critical workloads that they are designed to support

Loneliness in the United States: A 2018 National Panel Survey of Demographic, Structural, Cognitive, and Behavioral Characteristics

Purpose: To inform health behavior intervention design, we sought to quantify loneliness and its correlates, including social media use, among adults in the United States. Design: Cross-sectional research panel questionnaire. Setting: Responses were gathered from individuals in all 50 states surveyed via Internet from February 2018 to March 2018. Participants: A total of 20 096 US panel respondents aged 18þ. Measures: The University of California at Los Angeles (UCLA) Loneliness Scale (theoretical score range ¼ 20-80) was administered along with demographic, structural, cognitive, and behavioral items. Analysis: After calibrating the sample to population norms, we conducted multivariable linear regression analysis. Results: The overall mean survey-weighted loneliness score was 44.03 (standard error ¼ 0.09). Social support (standardized b [sb] ¼ 0.19) and meaningful daily interactions (sb ¼ 0.14) had the strongest associations with lower loneliness, along with reporting good relationships, family life, physical and mental health, friendships, greater age, being in a couple, and balancing one’s daily time. Social anxiety was most strongly associated with greater loneliness (sb ¼ þ0.20), followed by self-reported social media overuse (sb ¼ þ0.05) and daily use of text-based social media (sb ¼ þ0.03). Conclusion: Our findings confirm that loneliness decreases with age, and that being in a relationship as well as everyday behavioral factors in people’s control are most strongly related to loneliness. Population health promotion efforts to reduce loneliness should focus on improving social support, decreasing social anxiety, and promoting healthy daily behaviors