Caffeine has no effect on submaximal running in hypoxia in low caffeine consuming males and females.

Background: Exposure to hypoxia immediately challenges a variety of physiologic systems that limit exercise capacity. Under normoxia, caffeine (CAFF) increases ventilation and subsequent oxygenation of hemoglobin (SpO2) and skeletal muscle (SmO2). CAFF improves exercise performance at altitude.

Large motherhood penalties in US administrative microdata.

Whereas previous research has described motherhood penalties in US survey data, we leverage administrative data on 811,000 quarterly earnings histories from the US Unemployment Insurance program. We analyze contexts where smaller motherhood penalties might be expected: couples where the woman outearns her male partner prior to childbearing, at firms that are headed by women, and at firms that are predominantly women. Our startling result is that none of these propitious contexts appear to diminish the motherhood penalty, and indeed, the gap often increases in magnitude over time following childbearing.

Reduced trolling on Russian holidays and daily US Presidential election odds.

Russian trolls generally supported the Trump campaign and were particularly active on Twitter 2015-2017. We find that trolling fell 35% on Russian holidays and to a lesser extent, when temperatures were cold in St. Petersburg.

Perinatal health among 1 million Chinese-Americans.

The literature on "missing girls" suggests a net preference for sons both in China and among Chinese immigrants to the West. Perhaps surprisingly, we find that newborn Chinese-American girls are treated more intensively in US hospitals: they are kept longer following delivery, have more medical procedures performed, and have more hospital charges than predicted (by the non-Chinese gender difference). What might explain more aggressive medical treatment? We posit that hospitals are responding to worse health at birth of Chinese-American girls.

Livestock plants and COVID-19 transmission.

Policy responses to the COVID-19 outbreak must strike a balance between maintaining essential supply chains and limiting the spread of the virus. Our results indicate a strong positive relationship between livestock-processing plants and local community transmission of COVID-19, suggesting that these plants may act as transmission vectors into the surrounding population and accelerate the spread of the virus beyond what would be predicted solely by population risk characteristics. We estimate the total excess COVID-19 cases and deaths associated with proximity to livestock plants to be 236,000 to 310,000 (6 to 8% of all US cases) and 4,300 to 5,200 (3 to 4% of all US deaths), respectively, as of July 21, 2020, with the vast majority likely related to community spread outside these plants.

Later bedtimes predict President Trump's performance.

Technology and social media use are increasingly associated with delays in nightly sleep. Here, we consider the timing of President Trump's official Twitter account posts as a proxy for sleep duration and how it relates to his public performance. The President wakes around 6am, a routine which has not changed since early 2017.

From Heterocycles to Carbacycles: Synthesis of Carbocyclic Nucleoside Analogues from Enals and Hydroxylamines.

Substituted and stereochemically dense carbacycles can be prepared by sequential dipolar cycloaddition and reductive cleavage from enals and hydroxylamines. The reaction sequence proceeds with high efficiency for a wide variety of enals and hydroxylamines. The reaction is regio- and diastereoselective for the initial formation of a bridged bisisoxazolidine intermediate, which then undergoes quantitative double N-O cleavage to produce carbacycles as single diastereomers.

Synthesis of Chromenoisoxazolidines from Substituted Salicylic Nitrones via Visible-Light Photocatalysis.

This effort reports the first redox-neutral visible-light photocatalytic intramolecular dipolar cycloaddition for the diastereoselective synthesis of chromenoisoxazolidines. The authors have found that alkenylphenyl nitrones with a diverse substitution pattern on the aromatic ring and the alkenyl substituent undergo visible-light-promoted cycloadditions in the presence of catalytic amounts of Ru(bpy)Cl in high yields and selectivities. Evidence indicates that the proposed redox-neutral pathway is the predominant photoredox mechanism for this transformation.

Quantifying coal power plant responses to tighter SO emissions standards in China.

We evaluate the impact of China's new air pollution standards on sulfur dioxide (SO) emissions by comparing newly available data from Continuous Emissions Monitoring Systems (CEMS) at coal power plants with satellite measures. First, we show that following the July 2014 deadline for implementing tighter emissions standards, stack concentrations of SO reported by CEMS declined by 13.9%.

Son-biased sex ratios in 2010 US Census and 2011-2013 US natality data.

If gender bias is receding, demographic manifestations of son preference should also tend to decrease. The sex composition of US children provides a key barometer of gender preference. In the 2010 US Population Census, Chinese and Asian-Indian families are more likely to have a son after a daughter, consistent with previous research.

Provider and user acceptability of intermittent screening and treatment for the control of malaria in pregnancy in Malawi.

Background: Malaria in pregnancy is a major cause of adverse maternal and fetal outcomes. Intermittent preventive treatment with sulfadoxine-pyrimethamine (IPTp-SP) is one of the control strategies promoted by WHO. In response to mounting resistance to SP, intermittent screening and treatment (ISTp) has been proposed as an alternative.

Impacts of classifying New York City students as overweight.

US schools increasingly report body mass index (BMI) to students and their parents in annual fitness "report cards." We obtained 3,592,026 BMI reports for New York City public school students for 2007-2012. We focus on female students whose BMI puts them close to their age-specific cutoff for categorization as overweight.

An adaptive significance of morning sickness? Trivers-Willard and Hyperemesis Gravidarum.

Nausea during pregnancy, with or without vomiting, is a common early indication of pregnancy in humans. The severe form, Hyperemesis Gravidarum (HG), can be fatal. The aetiology of HG is unknown.

An Explanation of the Photoinduced Giant Dielectric Constant of Lead Halide Perovskite Solar Cells.

A photoinduced giant dielectric constant of ~10(6) has been found in impedance spectroscopy measurements of lead halide perovskite solar cells. We report similar effects in measurements of a porous lead zirconate titanate (PZT) sample saturated with water. The principal effect of the illumination of the solar cell and of the introduction of water into the pore volume of the PZT sample is a significant increase in conductivity and dielectric loss.

Auspicious birth dates among Chinese in California.

The number eight is considered lucky in Chinese culture, e.g. the Beijing Olympics began at 8:08 pm on 8/8/2008.

Paternity acknowledgment in 2 million birth records from Michigan.

Out-of-wedlock childbearing is more common in the U.S. than in other countries and becoming more so.

Resistance of Subtype C HIV-1 Strains to Anti-V3 Loop Antibodies.

HIV-1's subtype C V3 loop consensus sequence exhibits increased resistance to anti-V3 antibody-mediated neutralization as compared to the subtype B consensus sequence. The dynamic 3D structure of the consensus C V3 loop crown, visualized by ab initio folding, suggested that the resistance derives from structural rigidity and non-β-strand secondary protein structure in the N-terminal strand of the β-hairpin of the V3 loop crown, which is where most known anti-V3 loop antibodies bind. The observation of either rigidity or non-β-strand structure in this region correlated with observed resistance to antibody-mediated neutralization in a series of chimeric pseudovirus (psV) mutants.

The role of hospital heterogeneity in measuring marginal returns to medical care: a reply to Barreca, Guldi, Lindo, and Waddell.

In Almond et al. (2010), we describe how marginal returns to medical care can be estimated by comparing patients on either side of diagnostic thresholds. Our application examines at-risk newborns near the very low birth weight threshold at 1500 g.

Killing Me Softly: The Fetal Origins Hypothesis.

In the epidemiological literature, the fetal origins hypothesis associated with David J. Barker posits that chronic, degenerative conditions of adult health, including heart disease and type 2 diabetes, may be triggered by circumstance decades earlier, nutrition in particular. Economists have expanded on this hypothesis, investigating a broader range of fetal shocks and circumstances and have found a wealth of later-life impacts on outcomes including test scores, educational attainment, and income, along with health.

Public vs. private provision of charity care? Evidence from the expiration of Hill-Burton requirements in Florida.

This paper explores the consequences of the expiration of charity care requirements imposed on private hospitals by the Hill-Burton Act. We examine delivery care and the health of newborns using the universe of Florida births from 1989 to 2003 combined with hospital data from the American Hospital Association. We find that charity care requirements were binding on hospitals, but that private hospitals under obligation "cream skimmed" the least risky maternity patients.

Assessment of immunologically relevant dynamic tertiary structural features of the HIV-1 V3 loop crown R2 sequence by ab initio folding.

The antigenic diversity of HIV-1 has long been an obstacle to vaccine design, and this variability is especially pronounced in the V3 loop of the virus' surface envelope glycoprotein. We previously proposed that the crown of the V3 loop, although dynamic and sequence variable, is constrained throughout the population of HIV-1 viruses to an immunologically relevant β-hairpin tertiary structure. Importantly, there are thousands of different V3 loop crown sequences in circulating HIV-1 viruses, making 3D structural characterization of trends across the diversity of viruses difficult or impossible by crystallography or NMR.

Structural conservation predominates over sequence variability in the crown of HIV type 1's V3 loop.

The diversity of HIV-1 is a confounding problem for vaccine design, as the human immune response appears to favor poor or strain-specific responses to any given HIV-1 virus strain. A significant portion of this diversity is manifested as sequence variability in the loops of HIV-1's surface envelope glycoprotein. Here we show that the most variable sequence positions in the third variable (V3) loop crown cluster to a small zone on the surface of one face of the V3 loop ss-hairpin conformation.