869 research outputs found

    A Comparison of Markers of Iron Status between Vegetarian and Non-Vegetarian Female High School Cross Country Runners. Is Routine, Pre-Season Screening Warranted?

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    The purpose of the present study is to determine whether the circulating markers of iron status differ between vegetarian or non-vegetarian adolescent female high school cross-country runners. Fifteen non-vegetarian and six vegetarian female cross-country runners completed questionnaires used to obtain anthropometric data, health history, menstrual status, diet history and training history. Dietary intake was determined by self-report, using a food frequency questionnaire and a 3-day diet record. Blood samples were analyzed for serum iron, total iron binding capacity, serum ferritin, and transferrin saturation. No significant difference was found between vegetarians and non-vegetarians for serum iron or transferrin saturation. However, TIBC was significantly higher in vegetarians (p \u3c 0.05). Ferritin was lower in vegetarians, trending toward significance (p \u3c 0.10). Study results suggest the need for routine pre-season iron screenings as well as nutrition education, aimed at improving iron status for vegetarian and non-vegetarian adolescent female endurance athletes

    Distribution of Amino Acids in Lunar Regolith

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    One of the most eagerly studied questions upon initial return of lunar samples was whether significant amounts of organic compounds, including amino acids, were present. Analyses during the 1970s produced only tentative and inconclusive identifications of indigenous amino acids. Those analyses were hampered by analytical difficulties including relative insensitivity to certain compounds, the inability to separate chiral enantiomers, and the lack of compound-specific isotopic measurements, which made it impossible to determine whether the detected amino acids were indigenous to the lunar samples or the results of contamination. Numerous advances have been made in instrumentation and methodology for amino acid characterization in extraterrestrial samples in the intervening years, yet the origin of amino acids in lunar regolith samples has been revisited only once for a single lunar sample, (3) and remains unclear. Here, we present initial data from the analyses of amino acid abundances in 12 lunar regolith samples. We discuss these abundances in the context of four potential amino acid sources: (1) terrestrial biological contamination; (2) contamination from lunar module (LM) exhaust; (3) derivation from solar windimplanted precursors; and (4) exogenous delivery from meteorites

    Distribution and Origin of Amino Acids in Lunar Regolith Samples

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    The existence of organic compounds on the lunar surface has been a question of interest from the Apollo era to the present. Investigations of amino acids immediately after collection of lunar samples yielded inconclusive identifications, in part due to analytical limitations including insensitivity to certain compounds, an inability to separate enantiomers, and lack of compound-specific isotopic measurements. It was not possible to determine if the detected amino acids were indigenous to the lunar samples or the result of terrestrial contamination. Recently, we presented initial data from the analysis of amino acid abundances in 12 lunar regolith samples and discussed those results in the context of four potential amino acid sources [5]. Here, we expand on our previous work, focusing on amino acid abundances and distributions in seven regolith samples and presenting the first compound-specific carbon isotopic ratios measured for amino acids in a lunar sample

    The development of a brief and objective method for evaluating moral sensitivity and reasoning in medical students

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    BACKGROUND: Most medical schools in Japan have incorporated mandatory courses on medical ethics. To this date, however, there is no established means of evaluating medical ethics education in Japan. This study looks 1) To develop a brief, objective method of evaluation for moral sensitivity and reasoning; 2) To conduct a test battery for the PIT and the DIT on medical students who are either currently in school or who have recently graduated (residents); 3) To investigate changes in moral sensitivity and reasoning between school years among medical students and residents. METHODS: Questionnaire survey: Two questionnaires were employed, the Problem Identification Test (PIT) for evaluation of moral sensitivity and a portion of the Defining Issues Test (DIT) for moral reasoning. Subjects consisted of 559 medical school students and 272 residents who recently graduated from the same medical school located in an urban area of Japan. RESULTS: PIT results showed an increase in moral sensitivity in 4(th )and 5(th )year students followed by a decrease in 6(th )year students and in residents. No change in moral development stage was observed. However, DIT results described a gradual rising shift in moral decision-making concerning euthanasia between school years. No valid correlation was observed between PIT and DIT questionnaires. CONCLUSION: This study's questionnaire survey, which incorporates both PIT and DIT, could be used as a brief and objective means of evaluating medical students' moral sensitivity and reasoning in Japan

    Position-sensitive detection of ultracold neutrons with an imaging camera and its implications to spectroscopy

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    Position-sensitive detection of ultracold neutrons (UCNs) is demonstrated using an imaging charge-coupled device (CCD) camera. A spatial resolution less than 15 μ\mum has been achieved, which is equivalent to an UCN energy resolution below 2 pico-electron-volts through the relation δE=m0gδx\delta E = m_0g \delta x. Here, the symbols δE\delta E, δx\delta x, m0m_0 and gg are the energy resolution, the spatial resolution, the neutron rest mass and the gravitational acceleration, respectively. A multilayer surface convertor described previously is used to capture UCNs and then emits visible light for CCD imaging. Particle identification and noise rejection are discussed through the use of light intensity profile analysis. This method allows different types of UCN spectroscopy and other applications.Comment: 12 figures, 28 pages, accepted for publication in NIM

    Status of the UCNÏ„ experiment

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    The neutron is the simplest nuclear system that can be used to probe the structure of the weak interaction and search for physics beyond the standard model. Measurements of neutron lifetime and β-decay correlation coefficients with precisions of 0.02% and 0.1%, respectively, would allow for stringent constraints on new physics. The UCNτ experiment uses an asymmetric magneto-gravitational UCN trap with in situ counting of surviving neutrons to measure the neutron lifetime, τ_n = 877.7s (0.7s)_(stat) (+0.4/−0.2s)_(sys). We discuss the recent result from UCNτ, the status of ongoing data collection and analysis, and the path toward a 0.25 s measurement of the neutron lifetime with UCNτ

    A boron-coated CCD camera for direct detection of Ultracold Neutrons (UCN)

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    A new boron-coated CCD camera is described for direct detection of ultracold neutrons (UCN) through the capture reactions 10^{10}B (n,α\alpha0γ\gamma)7^7Li (6%) and 10^{10}B(n,α\alpha1γ\gamma)7^7Li (94%). The experiments, which extend earlier works using a boron-coated ZnS:Ag scintillator, are based on direct detections of the neutron-capture byproducts in silicon. The high position resolution, energy resolution and particle ID performance of a scientific CCD allows for observation and identification of all the byproducts α\alpha, 7^7Li and γ\gamma (electron recoils). A signal-to-noise improvement on the order of 104^4 over the indirect method has been achieved. Sub-pixel position resolution of a few microns is demonstrated. The technology can also be used to build UCN detectors with an area on the order of 1 m2^2. The combination of micrometer scale spatial resolution, few electrons ionization thresholds and large area paves the way to new research avenues including quantum physics of UCN and high-resolution neutron imaging and spectroscopy.Comment: 10 pages, 8 figure
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