RESUMO
An emerging theme in modern astrophysics is the connection between astronomical observations and the underlying physical phenomena that drive our cosmos. Both the mechanisms responsible for the observed astrophysical phenomena and the tools used to probe such phenomena-the radiation and particle spectra we observe-have their roots in atomic, molecular, condensed matter, plasma, nuclear and particle physics. Chemistry is implicitly included in both molecular and condensed matter physics. This connection is the theme of the present report, which provides a broad, though non-exhaustive, overview of progress in our understanding of the cosmos resulting from recent theoretical and experimental advances in what is commonly called laboratory astrophysics. This work, carried out by a diverse community of laboratory astrophysicists, is increasingly important as astrophysics transitions into an era of precise measurement and high fidelity modeling.
RESUMO
We report a fully relativistic close-coupling calculation of the electron impact excitation of Ni xix to derive the 3C/3D line intensity ratio, with an uncertainty of 5%. Convergence of the calculation with respect to both channel coupling effects and the many interacting Rydberg series of resonances has been achieved. New measurements in an electron beam ion trap agree with our calculation. We show that the 3C/3D x-ray line ratio depends sensitively on both electron energy and beamwidth in an optically thin plasma. Accounting for this dependence improves the accuracy of the Ni abundance determination in astrophysical sources.
RESUMO
Spectra of highly charged Kr ions, produced in an electron-beam ion trap (EBIT), have been recorded in a broad x-ray energy band (0.3 keV to 4 keV) with a microcalorimeter detector. Most of the spectral lines have been identified as transitions of B- to Al-like Kr. The transition energies have been determined with 0.2% uncertainty. A semi-empirical EBIT plasma model has been created to calculate a synthetic spectrum of highly charged Kr and to determine a charge state distribution of Kr ions inside the EBIT.
RESUMO
Surgical wound morbidity was analyzed for a U.S. military field hospital deployed to the Republic of Haiti in support of Operation New Horizons 1998. The purpose of the analysis was to determine if procedures performed in the field hospital had greater infectious risks as a result of the environment compared with historical reports for traditional hospital or clinic settings. Acceptable historical infection rates of 1.5% for clean surgical cases, 7.7% for clean contaminated cases, 15.2% for contaminated cases, and 40% for dirty cases have been noted. There were 827 operations performed during a 6-month period, with the majority of patients assigned American Society of Anesthesiologists Physical Status Classification class I or II. The distribution of these cases was: 72% clean cases, 5% clean contaminated cases, 4% contaminated cases, and 19% dirty cases. The overall wound complication rate was 3.6%, which included 5 wound infections, 11 wound hematomas, 8 superficial wound separations, and 6 seromas. The infectious morbidity for clean cases, the index for evaluation of infectious complications, was 0.8%, well within the accepted standards. There were two major complications that required a return to the operating room: a wound dehiscence with infection in an orchiectomy, and a postoperative hematoma with airway compromise in a subtotal thyroidectomy. There were no surgical mortalities. The infectious wound morbidity for operations performed in the field hospital environment was found to be equivalent to that described for the fixed hospital or clinic settings. No special precautions were necessary to ensure a low infection rate. The safety for patients undergoing elective surgical procedures has been established. Further training using these types of facilities should not be limited based on concerns for surgical wound morbidity.
