Browsing by Subject "principles"

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    Collision-Induced Absorption By Supermolecular Complexes From A New Potential Energy And Induced Dipole Surface, Suited For Calculations Up To Thousands Of Kelvin
    (2010-06) Abel, M.; Frommhold, L.; Wang, F.; Gustafsson, M.; Li, X. P.; Hunt, K. L. C.; Abel, Martin; Frommhold, Lothar
    Absorption by pairs of H-2 molecules is an important opacity source in the atmospheres of the outer planets, and thus of special astronomical interest. The emission spectra of cool white dwarf stars differ significantly from the expected blackbody spectra, amongst other reasons due to absorption by H-2 H-2, H-2 He, and H-2-H collisional complexes in the stellar atmospheres. To model the radiative processes in these atmospheres, which have temperatures of several thousand kelvin, one needs accurate knowledge of the induced dipole (ID) and potential energy surfaces (PES) of such collisional complexes. These come from quantum-chemical calculations with the H-2 bonds stretched or compressed far from equilibrium. Laboratory measurements of collision-induced (CI) absorption exist only at much lower temperature. For H-2 pairs at room temperature, the calculated spectra of the rototranslational band, the fundamental band, and the first overtone match the experimental data very well. In addition, with the newly obtained IDS it became possible to reproduce the measurements in the far blue wing of the rototranslational spectrum of H-2 at 77.5 K, as well as at 300 K. Similarly good agreement between theory and measurement is seen in the fundamental band of molecular deuterium at room temperature. Furthermore, we also show the calculated absorption spectra of H-2-He at 600 K and of H-2-H-2 at 2,000 K, for which there are no experimental data for comparison.
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    Letter to H.B. Stenzel from J.R. Schramm on 1939-10-30
    (1939-10-30) Schramm, J.R.
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    Outpatient Antibiotic Prescribing in the United States: 2000 to 2010
    (2014-06) Lee, Grace C.; Reveles, Kelly R.; Attridge, Russell T.; Lawson, Kenneth A.; Mansi, Ishak A.; Lewis, James S.; Frei, Christopher R.; Lee, Grace C.; Reveles, Kelly R.; Lawson, Kenneth A.; Lewis, James S.; Frei, Christopher R.
    The use of antibiotics is the single most important driver in antibiotic resistance. Nevertheless, antibiotic overuse remains common. Decline in antibiotic prescribing in the United States coincided with the launch of national educational campaigns in the 1990s and other interventions, including the introduction of routine infant immunizations with the pneumococcal conjugate vaccine (PCV-7); however, it is unknown if these trends have been sustained through recent measurements. Methods: We performed an analysis of nationally representative data from the Medical Expenditure Panel Surveys from 2000 to 2010. Trends in population-based prescribing were examined for overall antibiotics, broad-spectrum antibiotics, antibiotics for acute respiratory tract infections (ARTIs) and antibiotics prescribed during ARTI visits. Rates were reported for three age groups: children and adolescents (<18 years), adults (18 to 64 years), and older adults (>= 65 years). Results: An estimated 1.4 billion antibiotics were dispensed over the study period. Overall antibiotic prescribing decreased 18% (risk ratio (RR) 0.82, 95% confidence interval (95% CI) 0.72 to 0.94) among children and adolescents, remained unchanged for adults, and increased 30% (1.30, 1.14 to 1.49) among older adults. Rates of broad-spectrum antibiotic prescriptions doubled from 2000 to 2010 (2.11, 1.81 to 2.47). Proportions of broad-spectrum antibiotic prescribing increased across all age groups: 79% (1.79, 1.52 to 2.11) for children and adolescents, 143% (2.43, 2.07 to 2.86) for adults and 68% (1.68, 1.45 to 1.94) for older adults. ARTI antibiotic prescribing decreased 57% (0.43, 0.35 to 0.52) among children and adolescents and 38% (0.62, 0.48 to 0.80) among adults; however, it remained unchanged among older adults. While the number of ARTI visits declined by 19%, patients with ARTI visits were more likely to receive an antibiotic (73% versus 64%; P < 0.001) in 2010 than in 2000. Conclusions: Antibiotic use has decreased among children and adolescents, but has increased for older adults. Broad-spectrum antibiotic prescribing continues to be on the rise. Public policy initiatives to promote the judicious use of antibiotics should continue and programs targeting older adults should be developed.