45 research outputs found

    Measurement of hydrogen depth distribution by resonant nuclear reactions

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    The resonance at E (19F) =6.42 MeV in the reaction 1H(19F,alphagamma)16O has been explored as a potentially useful method for the quantitative determination of hydrogen concentration as a function of depth in a solid substrate. The relative merits of this resonance, the 16.44-MeV resonance in the same reaction, and the 6.39-MeV resonance in the reaction 1H(15N,alphagamma)12C are discussed

    Highly Excited States in C11. Elastic Scattering of Protons by B10

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    Excitation functions for the elastic scattering of protons by B10 have been measured at center-of-mass scattering angles near 90°, 125°, and 160° for proton energies between Ep=0.15 MeV and Ep=3.0 MeV. Scattering angular distributions were measured at 43 selected energies in this range. An excitation function for the reaction B10(p, α0)Be7 was also measured between Ep=1.5 MeV and Ep=2.6 MeV at a laboratory angle of 90°. The atomic stopping cross section of boron for protons has been determined between Ep=0.1 MeV and Ep=3.0 MeV. The elastic scattering excitation functions exhibit conspicuous anomalies at Ep=1.50 MeV and Ep=2.180 MeV. The α0 transition to the ground state of Be7 is also resonant at Ep=2.180 MeV. The behavior of the cross sections in these regions has been analyzed in terms of compound states of C11. Satisfactory agreement is achieved with level assignments of Jπ=7/2+ with ER=1.50 MeV, Γp=90 keV, ΓT=250 keV; and Jπ=9/2+ with ER=2.180 MeV, Γp=100 keV, Γα0=100 kev, and ΓT=200 keV. Although complete analysis of the scattering is hindered by the influence of unknown background processes, the negative parity assignment for the previously reported state at Ep=1.17 MeV, derived from other reaction experiments, appears inconsistent with the scattering

    Scanning Transmission Ion Microscopy as it Complements Particle Induced X-Ray Emission Microanalysis

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    The early uses of Scanning Transmission Ion Microscopy (STIM) with MeV ions are reviewed. The transformation of STIM energy-loss images into maps of areal density is discussed, and is illustrated with images of a fruit fly head (Drosophila melanogaster). Freeze-dried male heads are transparent to 4-MeV protons in the dorsal and frontal directions, but in the sagittal direction the brain is opaque. STIM with molecular ions is shown to be useful for increasing contrast in low density areas. For recording registered STIM and PIXE images without changing accelerator parameters, apertures are used to accomplish the required change in beam intensity (a factor of 105). Molecular ions are used to assess contamination of the microbeam by scattered ions. Pixel by pixel ratios of x-ray intensity to areal density are taken to obtain maps of element concentrations. Calcium and iron maps are shown. Inner parts of the fly head are clearly seen in the concentration maps. The PIXE exposure caused differential displacements of inner parts of the head by 15 ÎŒm or less. Weight loss during the PIXE exposure was measured to be 3%

    Education, Employment, and America’s Opioid Epidemic

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    America is embroiled in an opioid epidemic that continues to take a toll on American citizens’ quality of life, utility, and mortality rates, as well as the nation’s economy. Researchers have examined information from Substance Abuse and Mental Health Services Administration’s (SAMHSA) Treatment Episode Data Set (TEDS) (Drug and Alcohol Services Information Systems [DASIS], 2009) in order to get an idea about which populations are able to access opioid treatment in America, the District of Columbia, and Puerto Rico. Details of education levels and employment rates for those being treated could offer answers about individuals and populations impacted by the opioid epidemic. The purpose of this study was to examine whether individuals who had been in treatment for heroin and/or opioids in 2014 have a higher level of education than individuals in treatment for heroin and/or opioids in 1998, and to determine if individuals in treatment for heroin and/or opioids in 2014 have higher rates of employment than individuals in treatment for heroin and/or opioids in 1998 (DASIS, 2009). Researchers used a T-test on the TEDS and found statistically significant changes in levels of education and static rates of employment from 1998 to 2014 (DASIS, 2009)

    Determination of Omega_b From Big Bang Nucleosynthesis in the Presence of Regions of Antimatter

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    Production of regions of antimatter in the early universe is predicted in many baryogenesis models. Small scale antimatter regions would annihilate during or soon after nucleosynthesis, affecting the abundances of the light elements. In this paper we study how the acceptable range in Omega_b changes in the presence of antimatter regions, as compared to the standard big bang nucleosynthesis. It turns out that it is possible to produce at the same time both a low 4He value (Y_p < 0.240) and a low D/H value (D/H < 4e-5), but overproduction of 7Li is unavoidable at large Omega_b.Comment: 9 pages, PRD version, ref. 6 correcte

    Developing the Agile Implementation Playbook for Integrating Evidence-Based Health Care Services into Clinical Practice

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    Problem: Despite the more than $32 billion the National Institutes of Health has invested annually, evidence-based health care services are not reliably implemented, sustained, or distributed in health care delivery organizations, resulting in suboptimal care and patient harm. New organizational approaches and frameworks that reflect the complex nature of health care systems are needed to achieve this goal. Approach: To guide the implementation of evidence-based health care services at their institution, the authors used a number of behavioral theories and frameworks to develop the Agile Implementation (AI) Playbook, which was finalized in 2015. The AI Playbook leverages these theories in an integrated approach to selecting an evidence-based health care service to meet a specific opportunity, rapidly implementing the service, evaluating its fidelity and impact, and sustaining and scaling up the service across health care delivery organizations. The AI Playbook includes an interconnected eight-step cycle: (1) identify opportunities; (2) identify evidence-based health care services; (3) develop evaluation and termination plans; (4) assemble a team to develop a minimally viable service; (5) perform implementation sprints; (6) monitor implementation performance; (7) monitor whole system performance; and (8) develop a minimally standardized operating procedure. Outcomes: The AI Playbook has helped to improve care and clinical outcomes for intensive care unit survivors and is being used to train clinicians and scientists in AI to be quality improvement advisors. Next Steps: The authors plan to continue disseminating the details of the AI Playbook and illustrating how health care delivery organizations can successfully leverage it

    Updated Nucleosynthesis Constraints on Unstable Relic Particles

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    We revisit the upper limits on the abundance of unstable massive relic particles provided by the success of Big-Bang Nucleosynthesis calculations. We use the cosmic microwave background data to constrain the baryon-to-photon ratio, and incorporate an extensively updated compilation of cross sections into a new calculation of the network of reactions induced by electromagnetic showers that create and destroy the light elements deuterium, he3, he4, li6 and li7. We derive analytic approximations that complement and check the full numerical calculations. Considerations of the abundances of he4 and li6 exclude exceptional regions of parameter space that would otherwise have been permitted by deuterium alone. We illustrate our results by applying them to massive gravitinos. If they weigh ~100 GeV, their primordial abundance should have been below about 10^{-13} of the total entropy. This would imply an upper limit on the reheating temperature of a few times 10^7 GeV, which could be a potential difficulty for some models of inflation. We discuss possible ways of evading this problem.Comment: 40 pages LaTeX, 18 eps figure
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