Detection of HIV-1 infection in dried blood spots from a 12-year-old ABO bedside test card

Background and Objectives: We tested dried blood from an ABO bedside test card which had been stored at room temperature for 12 years, to prove that a patient with HIV-1 infection had been infected by blood transfusion. Materials and Methods: Immunoblots for HIV-1 antibodies and threefold PCRs with half-nested primers for the HIV-1 integrase gene were done with eluates from the dried blood spots. Results: HIV-1 antibodies and HIV-1 DNA could be detected in the sample from one unit of blood, but not from the two other units or from the recipient before transfusion. Conclusion: Further studies should be done on the validity of stored dried blood as an alternative to the storage of frozen donor serum for several years for `look-back' studies

On the appearance of hyperons in neutron stars

By employing a recently constructed hyperon-nucleon potential the equation of state of \beta-equilibrated and charge neutral nucleonic matter is calculated. The hyperon-nucleon potential is a low-momentum potential which is obtained within a renormalization group framework. Based on the Hartree-Fock approximation at zero temperature the densities at which hyperons appear in neutron stars are estimated. For several different bare hyperon-nucleon potentials and a wide range of nuclear matter parameters it is found that hyperons in neutron stars are always present. These findings have profound consequences for the mass and radius of neutron stars.Comment: 12 pages, 12 figures, RevTeX4; summary and conclusions are strengthened, to appear in PR

Hybrid protoneutron stars with the MIT bag model

We study the hadron-quark phase transition in the interior of protoneutron stars. For the hadronic sector, we use a microscopic equation of state involving nucleons and hyperons derived within the finite-temperature Brueckner-Bethe-Goldstone many-body theory, with realistic two-body and three-body forces. For the description of quark matter, we employ the MIT bag model both with a constant and a density-dependent bag parameter. We calculate the structure of protostars with the equation of state comprising both phases and find maximum masses below 1.6 solar masses. Metastable heavy hybrid protostars are not found.Comment: 12 pages, 9 figures submitted to Phys. Rev.

The Lived Experience of Adults Using a Meditation App: A Phenomenological Study

Stress is increasingly prevalent in Western culture, and researchers associate it with physical and psychological health issues. Previous research indicates meditation, specifically through meditation apps on smartphones, is beneficial for reducing stress. However, limited research addresses qualitative data regarding meditation apps; therefore, this study describes the lived experience of adults using a meditation app called Headspace. We used phenomenology as a method to describe the essence of participant lived experiences. We collected qualitative data by having twelve adults journal about their experiences after completing a series of ten meditation app sessions. We completed a thematic analysis with the journal entries, which resulted in six emerging themes: relaxation, thoughts, emotions, senses, breathing, and reduced stress. Results suggest that meditation using Headspace is beneficial for relaxation and reducing stress in adults in Western culture. Implications for holistic health include that practitioners have a new method of promoting relaxation and stress reduction to their clients. Further research could be conducted to measure quantitative relaxation and stress reduction in adults experiencing stress in Western culture using the Headspace app

Io: IUE observations of its atmosphere and the plasma torus

Two of the main components of the atmosphere of Io, neutral oxygen and sulfur, were detected with the IUE. Four observations yield brightnesses that are similar, regardless of whether the upstream or the downstream sides of the torus plasma flow around Io is observed. A simple model requires the emissions to be produced by the interaction of O and S columns in the exospheric range with 2 eV electrons. Cooling of the 5 eV torus electrons is required prior to their interaction with the atmosphere of Io. Inconsistencies in the characteristics of the spectra that cannot be accounted for in this model require further analysis with improved atomic data. The Io plasma torus was monitored with the IUE. The long-term stability of the warm torus is established. The observed brightnesses were analyzed using a model of the torus, and variations of less than 30 percent in the composition are observed, the quantitative results being model dependent

Identification of volatile contaminants of space cabin materials Final report, Jan. - Jun. 1969

Identification of volatile contaminants of space cabin material

The structure of Io's thermal corona and implications for atmospheric escape

We investigate the escape of species from Io's atmosphere using a steady-state model of Io's exospheric corona and its interaction with the Io plasma torus. The corona is assumed to be spherically symmetric with the radial density and compositional structure determined by the gas kinetic temperature, critical level radius, and mixing ratios of the component species. Thermal and nonthermal escape rates are calculated and the results compared with previously estimated torus and neutral cloud supply rates for O, S, Na, and K. Both oxygen- and sulfur-dominated exospheres are considered. Atmospheric sputtering is found to be the major escape mechanism for models in which the plasma flow reaches the critical level. However, such models produce total mass-loading rates an order of magnitude larger than inferred values suggesting that either (1) the structure of the thermal corona is significantly modified by the nonthermal interaction, or (2) substantial plasma flow modification and deflection occurs in the corona at or above the critical level. Assuming that the thermal model is a correct description of the corona, a comparison of these results with the observed near-Io distribution of neutral Na and estimated source rates for the neutral Na "jets" suggests an extended Na coronal component. Assuming that this component is part of the thermal exosphere, we find that the observations are consistent with an O-dominated corona, an exospheric temperature ~1000 K, a 0.001 critical level mixing ratio of Na, and a critical level radius ~1.5 R_(Io)

Survey for Transiting Extrasolar Planets in Stellar Systems. II. Spectrophotometry and Metallicities of Open Clusters

We present metallicity estimates for seven open clusters based on spectrophotometric indices from moderate-resolution spectroscopy. Observations of field giants of known metallicity provide a correlation between the spectroscopic indices and the metallicity of open cluster giants. We use \chi^2 analysis to fit the relation of spectrophotometric indices to metallicity in field giants. The resulting function allows an estimate of the target-cluster giants' metallicities with an error in the method of \pm0.08 dex. We derive the following metallicities for the seven open clusters: NGC 1245, [m/H]=-0.14\pm0.04; NGC 2099, [m/H]=+0.05\pm0.05; NGC 2324, [m/H]=-0.06\pm0.04; NGC 2539, [m/H]=-0.04\pm0.03; NGC 2682 (M67), [m/H]=-0.05\pm0.02; NGC 6705, [m/H]=+0.14\pm0.08; NGC 6819, [m/H]=-0.07\pm0.12. These metallicity estimates will be useful in planning future extra-solar planet transit searches since planets may form more readily in metal-rich environments.Comment: 38 pages, including 12 figures. Accepted for publication in A

Test-enhanced learning of clinical reasoning: a crossover randomised trial

CONTEXT: Clinical reasoning is an essential skill, the foundations of which should be acquired during undergraduate medical education. Student performance in clinical reasoning can be assessed using key feature examinations. However, within a paradigm of test-enhanced learning, such examinations may also be used to enhance long-term retention of procedural knowledge relevant to clinical reasoning. OBJECTIVES: This study tested the hypothesis that repeated testing with key feature questions is more effective than repeated case-based learning in fostering clinical reasoning. METHODS: In this randomised crossover trial, Year 4 medical students attended 10 weekly computer-based seminars during which patient case histories covering general medical conditions were displayed. The presentation format was switched between groups every week. In the control condition, students studied long case narratives. The intervention condition used the same content but augmented case presentation with a sequence of key feature questions. Using a within-subjects design, student performance on intervention and control items was assessed at 13 weeks (exit examination) and 9 months (retention test) after the first day of term. RESULTS: A total of 87 of 124 eligible students provided complete data for the longitudinal analysis (response rate: 70.2%). In the retention test, mean ± standard deviation student scores on intervention items were significantly higher than those on control items (56.0 ± 25.8% versus 48.8 ± 24.7%; p < 0.001). The results remained unchanged after accounting for exposure time in a linear regression analysis that also adjusted for sex and general student performance levels. CONCLUSIONS: This is the first study to demonstrate an effect of test-enhanced learning on clinical reasoning as assessed with key feature questions. In this randomised trial, repeated testing was more effective than repeated case-based learning alone. Curricular implementation of longitudinal key feature testing may considerably enhance student learning outcomes in relevant aspects of clinical medicine