895 research outputs found

    Common intestinal protozoa of man: life cycle charts

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    prepated by M.M. Brooke and Dorothy M. Melvin, Laboratory Consultation and Development Section, Laboratory Branch.Originally issued in 1960 as an unnumbered publication by the Laboratory Branch of the Communicable Disease Center for use in training courses

    Keck telescope constraint on cosmological variation of the proton-to-electron mass ratio

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    Molecular transitions recently discovered at redshift z_abs=2.059 toward the bright background quasar J2123-0050 are analysed to limit cosmological variation in the proton-to-electron mass ratio, mu=m_p/m_e. Observed with the Keck telescope, the optical echelle spectrum has the highest resolving power and largest number (86) of H_2 transitions in such analyses so far. Also, (seven) HD transitions are used for the first time to constrain mu-variation. These factors, and an analysis employing the fewest possible free parameters, strongly constrain mu's relative deviation from the current laboratory value: dmu/mu =(+5.6+/-5.5_stat+/-2.9_sys)x10^{-6}, indicating an insignificantly larger mu in the absorber. This is the first Keck result to complement recent null constraints from three systems at z_abs>2.5 observed with the Very Large Telescope. The main possible systematic errors stem from wavelength calibration uncertainties. In particular, distortions in the wavelength solution on echelle order scales are estimated to contribute approximately half the total systematic error component, but our estimate is model dependent and may therefore under or overestimate the real effect, if present. To assist future mu-variation analyses of this kind, and other astrophysical studies of H_2 in general, we provide a compilation of the most precise laboratory wavelengths and calculated parameters important for absorption-line work with H_2 transitions redwards of the hydrogen Lyman limit.Comment: 15 pages, 8 figures (8 EPS files), 3 tables. Accepted by MNRAS. ArXiv copy includes full version of Fig. 1 (additional 8 pages, 7 EPS files). Complete version of Table 1 available at http://astronomy.swin.edu.au/~mmurphy/pub.htm

    Trends in the Environmental Health Job Market for New Graduates

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    The question of whether the job market can support future graduates of environmental health programs remains an important and difficult question for environmental health programs, current and prospective students, parents, and other stakeholders. Our previous report using 2014 data from the U.S. Bureau of Labor Statistics demonstrated anticipated growth and higher than average pay in the profession through at least 2022 for baccalaureate degree holders (Marion & Sinde, 2015). Growth in the profession does not necessarily translate into job availability if the market is saturated with job candidates. While university programs produce graduates, local health departments (LHDs) have suffered tremendous job losses nationally. Although there was a net gain of 850 positions in LHDs in 2016, the U.S. has 50,000 fewer LHD employees today than one decade ago. For monitoring potential changes in job availability, an annual survey is performed among the 32 programs accredited by the National Environmental Health Science and Protection Accreditation Council (EHAC). The results of the last six surveys (2012 - 2017) pertaining to job outlooks were evaluated. Using the responses to the overarching categories of public sector and private sector employment, descriptive analyses and a logistic regression model were performed to see if programs perceiving increasing job growth were oriented more toward having graduates placed in private sector positions. Overall, over half of accredited EHAC undergraduate and graduate programs perceive increasing job opportunities for their graduating students. The programs most closely aligned to the private sector reported more favorable job outlook scenarios for their graduates. Specifically, the odds of perceiving an increasing market for graduates increased six-fold for each percent increase in the number of recent graduates working in private industry (OR = 6.0, 95% CI: 1.1, 32). Most of the programs that are most closely aligned to public sector employment opportunities perceive either no change or increasing opportunities in the job market. Future studies among recent graduates taking into consideration salary differences between public and private employers are encouraged. Such discrepancies, if any, between public versus private salaries among EHAC graduates could be useful in informing environmental public health budgets and policies

    Fostering global science networks in a Post-COVID-19 world

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    To restrict the spread of COVID-19 disease, regional and national governments have implemented a range of communitybased measures. Physical distancing has closed offices and laboratories, canceled fieldwork and research cruises, and led to scientific productivity declines, notably of female scientists (Staniscuaski et al., 2020; Viglione, 2020; Vincent-Lamarr et al., 2020.) The cessation of international travel was an early measure that looks like it may be continuing for some time.info:eu-repo/semantics/publishedVersio

    EVLA Observations of the Radio Evolution of SN 2011dh

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    We report on Expanded Very Large Array (EVLA) observations of the Type IIb supernova 2011dh, performed over the first 100 days of its evolution and spanning 1-40 GHz in frequency. The radio emission is well-described by the self-similar propagation of a spherical shockwave, generated as the supernova ejecta interact with the local circumstellar environment. Modeling this emission with a standard synchrotron self-absorption (SSA) model gives an average expansion velocity of v \approx 0.1c, supporting the classification of the progenitor as a compact star (R_* \approx 10^11 cm). We find that the circumstellar density is consistent with a {\rho} \propto r^-2 profile. We determine that the progenitor shed mass at a constant rate of \approx 3 \times 10^-5 M_\odot / yr, assuming a wind velocity of 1000 km / s (values appropriate for a Wolf-Rayet star), or \approx 7 \times 10^-7 M_\odot / yr assuming 20 km / s (appropriate for a yellow supergiant [YSG] star). Both values of the mass-loss rate assume a converted fraction of kinetic to magnetic energy density of {\epsilon}_B = 0.1. Although optical imaging shows the presence of a YSG, the rapid optical evolution and fast expansion argue that the progenitor is a more compact star - perhaps a companion to the YSG. Furthermore, the excellent agreement of the radio properties of SN 2011dh with the SSA model implies that any YSG companion is likely in a wide, non-interacting orbit.Comment: 6 pages, 2 figures; accepted to ApJ

    Cost-effectiveness analysis of introducing HTLV-1 testing in South Africa

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    We have previously reported a 2013 cross-sectional study of HTLV prevalence among 46,765 South African blood donors. Confirmed HTLV-1 prevalence was 0.16% in Black donors, 0.02% in both White and Coloured donors and 0% in south Asian donors, for an overall prevalence of 0.062% extrapolated to the current blood donor population. Using these data we estimated the cost effectiveness of potential HTLV screening strategies in preventing transfusion transmitted HTLV-1 infection (TTI). Five blood donor screening strategies were considered: no screening; HTLV testing of every donation; HTLV testing each donor one time only; HTLV testing of new donors only; and universal filter leukodepletion without HTLV testing

    The Constancy of the Constants of Nature: Updates

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    The current observational and experimental bounds on the time variation of the constants of nature (the fine structure constant α\alpha, the gravitational constant GG and the proton-electron mass ratio μ=mp/me\mu=m_p/m_e) are reviewed.Comment: 27 pages, 2 figures, to be published in Prog.Theor.Phys, ref. adde

    Positive lifestyle changes around the time of pregnancy:a cross-sectional study

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    OBJECTIVES: To examine the prevalence of positive lifestyle behaviours before and during pregnancy in Ireland. DESIGN: Cross-sectional study. SETTING: Population-based study in Ireland. PARTICIPANTS: A total of 718 women of predominantly Caucasian origin from the Pregnancy Risk Assessment Monitoring System (PRAMS), Ireland, were included. PRIMARY AND SECONDARY OUTCOME MEASURES Positive lifestyle behaviour changes before and during pregnancy in Ireland on alcohol consumption, smoking, folate use and nutrition. RESULTS: Of 1212 women surveyed, 718 (59%) responded. 26% were adherent to all three recommendations on alcohol consumption, smoking and folate use before pregnancy. This increased to 39% for the same three behaviours during pregnancy, with greater increases in adherence observed among women with the lowest adherence before pregnancy. Age, education and ethnicity gaps in adherence before pregnancy appeared to narrow during pregnancy. Adherence to all seven food pyramid guidelines was less than 1% overall, and less than 1% of participants met all four micronutrient guidelines on vitamin D, folate, calcium and iron intake around the time of pregnancy. CONCLUSIONS: Low levels of healthy lifestyle behaviours before pregnancy and low levels of positive lifestyle behaviours during pregnancy demonstrate an urgent need for increased clinical and public health efforts to target deleterious health behaviours before, during and after pregnancy
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