Ground Water Quality Effects on Domestic Water Utilization

The work upon which this report is based was supported in part by funds (Project A-040-ALAS) provided by the United States Department of the Interior, Office of Water Resources Research, as authorized under the Water Resources Act of 1964, as amended

An O\u27Neill Institute Briefing Paper: Ebola, the World Health Organization, and Beyond: Toward a Framework for Global Health Security

The West African Ebola epidemic has demonstrated that the world remains ill-prepared to respond to infectious disease outbreaks. A host of institutions are now reviewing what went wrong, and new institutions are being considered, including an African Centers for Disease Control and Prevention and World Bank-initiated Pandemic Emergency Facility. The World Health Organization itself failed in one of its core functions by allowing a preventable infectious disease to spiral out of control in the world’s poorest region. The 68th World Health Assembly (WHA), held in May 2015, provided an opportunity for the Organization to reflect on what went wrong and reform the organization to be better able to address the next epidemic. In this Briefing Paper we lay out the present landscape, including reforms needed of the International Health Regulations, and assess the strengths and weaknesses of the outcomes of the 68th WHA, including integrating WHO’s outbreak and emergency response programs; creating a global health emergency workforce, deployable on short notice; and setting up a global health emergency contingency fund. We also consider the vital structural issues the WHA failed to effectively address, including bolstering WHO’s core funding, increasing coherence between the WHO headquarters and regional offices, and enhancing civil society engagement

Isotopic study of oxygen diffusion in oxide coatings

Diffusion of oxygen in thin films of silicon dioxide was studied using oxygen isotopically enriched in oxygen of atomic mass 18 (O-18). This subject is of interest because thin films of dielectrics such as SiO2 are proposed for use as a protective coatings for solar mirrors in low Earth orbit, which is a strongly oxidizing environment. Films of this material were prepared with a direct current magnetron using reactive sputtering techniques. To produce (O-18)- enriched SiO2, a standard 3.5-in.-diameter silicon wafer was reactively sputtered using (O-18)-enriched (95 percent) oxygen as the plasma feed gas. The films were characterized using Rutherford backscattering and Secondary Ion Mass Spectrometer (SIMS) to establish stoichiometry and purity. Subsequently, the films were exposed to an air-derived oxygen plasma in a standard laboratory plasma reactor for durations of up to 10 hr. The concentration ratio of O-16 as a function of depth was determined using SIMS profiling and compared to a baseline, nonplasma exposed sample. A value for the diffusivity of oxygen near the surface of these films was obtained and found to be about 10(-15)sq cm/sec

Cis-regulatory basis of sister cell type divergence in the vertebrate retina

Multicellular organisms evolved via repeated functional divergence of transcriptionally related sister cell types, but the mechanisms underlying sister cell type divergence are not well understood. Here, we study a canonical pair of sister cell types, retinal photoreceptors and bipolar cells, to identify the ke

Improved methods for simulating nearly extremal binary black holes

Astrophysical black holes could be nearly extremal (that is, rotating nearly as fast as possible); therefore, nearly extremal black holes could be among the binaries that current and future gravitational-wave observatories will detect. Predicting the gravitational waves emitted by merging black holes requires numerical-relativity simulations, but these simulations are especially challenging when one or both holes have mass $m$ and spin $S$ exceeding the Bowen-York limit of $S/m^2=0.93$. We present improved methods that enable us to simulate merging, nearly extremal black holes more robustly and more efficiently. We use these methods to simulate an unequal-mass, precessing binary black hole coalescence, where the larger black hole has $S/m^2=0.99$. We also use these methods to simulate a non-precessing binary black hole coalescence, where both black holes have $S/m^2=0.994$, nearly reaching the Novikov-Thorne upper bound for holes spun up by thin accretion disks. We demonstrate numerical convergence and estimate the numerical errors of the waveforms; we compare numerical waveforms from our simulations with post-Newtonian and effective-one-body waveforms; we compare the evolution of the black-hole masses and spins with analytic predictions; and we explore the effect of increasing spin magnitude on the orbital dynamics (the so-called "orbital hangup" effect).Comment: 18 pages, 18 figure

Mandatory SARS-CoV-2 Vaccinations in K-12 Schools, Colleges/Universities, and Businesses

The Centers for Disease Control and Prevention (CDC) recently issued guidance that fully vaccinated individuals can safely remove masks and end social distancing in most indoor settings. Educational facilities and businesses are faced with whether and how to differentiate between vaccinated and unvaccinated individuals, including requiring proof of vaccination. Mandatory vaccination has historically served as a tool to reach and sustain high immunization coverage and to prevent transmission in K-12 schools, colleges/universities, and health care facilities. Vaccine mandates could extend to workers and customers in businesses to ensure safer environments. This Viewpoint examines the epidemiologic, public health, and legal considerations for mandatory SARS-CoV-2 vaccinations in each setting

Sprawl Angle in Simplified Models of Vertical Climbing: Implications for Robots and Roaches

Empirical data taken from fast climbing sprawled posture animals reveals the presence of strong lateral forces with significant pendulous swaying of the mass center trajectory in a manner captured by a recently proposed dynamical template. In this simulation study we explore the potential benefits of pendulous dynamical climbing in animals and in robots by examining the stability and power advantages of variously more and less sprawled limb morphologies when driven by conventional motors in contrast with animal-like muscles. For open loop models of gait generation inspired by the neural-deprived regimes of high stride-frequency animal climbing, our results corroborate earlier hypotheses that sprawled posture may be required for stability. For quadratic-in- velocity power output actuation models typical of commercially available electromechanical actuators, our results suggest the new hypothesis that sprawled posture may confer significant energetic advantage. In notable contrast, muscle-powered climbers do not experience an energetic benefit from sprawled posture due to their sufficiently distinct actuator characteristics and operating regimes. These results suggest that the potentially significant benefits of sprawled posture climbing may be distinctly different depending upon the details of the climber\u27s sensorimotor endowment. They offer a cautionary instance against mere copying of biology by engineers or rote study of physical models by biologists through this reminder of how even simple questions addressed by simple models can yield nuanced answers that only begin to hint at the complexity of biological designs and behaviors