Burst annealing of high temperature GaAs solar cells

One of the major limitations of solar cells in space power systems is their vulnerability to radiation damage. One solution to this problem is to periodically heat the cells to anneal the radiation damage. Annealing was demonstrated with silicon cells. The obstacle to annealing of GaAs cells was their susceptibility to thermal damage at the temperatures required to completely anneal the radiation damage. GaAs cells with high temperature contacts and encapsulation were developed. The cells tested are designed for concentrator use at 30 suns AMO. The circular active area is 2.5 mm in diameter for an area of 0.05 sq cm. Typical one sun AMO efficiency of these cells is over 18 percent. The cells were demonstrated to be resistant to damage after thermal excursions in excess of 600 C. This high temperature tolerance should allow these cells to survive the annealing of radiation damage. A limited set of experiments were devised to investigate the feasibility of annealing these high temperature cells. The effect of repeated cycles of electron and proton irradiation was tested. The damage mechanisms were analyzed. Limitations in annealing recovery suggested improvements in cell design for more complete recovery. These preliminary experiments also indicate the need for further study to isolate damage mechanisms. The primary objective of the experiments was to demonstrate and quantify the annealing behavior of high temperature GaAs cells. Secondary objectives were to measure the radiation degradation and to determine the effect of repeated irradiation and anneal cycles

Glucocorticoid therapy for adrenal insufficiency: nonadherence, concerns and dissatisfaction with information

Objective: Appropriate self‐management of glucocorticoid therapy (GC) is crucial for patients with adrenal insufficiency (AI). We aimed to describe patients’ self‐reported nonadherence to GC, evaluate perceived doubts about need for GC, concerns about adverse effects, and dissatisfaction with information received about GC. Design: Cross‐sectional survey. Patients: Patients prescribed GC for AI (n = 81) from five European countries. Measurements: Online survey including the Medication Adherence Report Scale (MARS), Beliefs about Medicines Questionnaire© (BMQ Specific, adapted for AI) and Satisfaction with Information about Medicines Scale© (Prof Rob Horne; SIMS). Results: Most patients (85·2%) reported a degree of nonadherence to GC. The most frequent types of nonadherence concerned changing the timing of GC doses, for example taking a dose later in the day than advised (37·0%). Few patients doubted their personal need for daily GC, but most reported high concerns about GC including potential weight gain (50·6%), osteoporosis (53·6%) and the continuing risk of adrenal crisis (50·6%). Dissatisfaction with information about GC was frequent, with participants particularly dissatisfied with the amount of information they had received about potential problems with GC. People who expressed dissatisfaction with information about GC, and concerns about its adverse effects were also more likely to report nonadherence (P < 0·05). Conclusions: Nonadherence to treatment, concerns about potential adverse effects and dissatisfaction with the information provided about treatment were frequently reported by this European sample of AI patients. Many AI patients may need additional information about their GC and support to address concerns about GC and facilitate adherence

High spectral resolution time-resolved optical spectroscopy of V893 Sco

We present high resolution time-resolved optical spectra of the high inclination short orbital period dwarf nova V893 Sco. We performed spectral analysis through radial velocity measurements, Doppler mapping, and ratioed Doppler maps. Our results indicate that V893 Sco's accretion disk is dissimilar to WZ Sge's accretion disk, and does not fit any of the current accretion disk models. We derive the system parameters M1 and i, and present evidence for V893 Sco as a very young cataclysmic variable and an ER UMa star. We advance the hypothesis that all ER UMa stars may be newly formed cataclysmic variables.Comment: 23 pages (total), 8 figures, accepted by Ap

Space radiation equivalence for effects on transistors Final report, 15 May 1965 - 15 Nov. 1966

Space radiation equivalences for permanent damage to silicon transistors by measuring changes in transistor parameters after exposure to proton, electron, and gamma ray irradiatio

Two-band ferromagnetic Kondo-lattice model for local-moment half-metals

We introduce a two-band Kondo-lattice model to describe ferromagnetic half-metals with local magnetic moments. In a model study, the electronic and magnetic properties are presented by temperature dependent magnetization curves, band-structures, spin polarizations and plasma frequencies. These are obtained from numerically evaluated equations, based on the single-electron Green functions. We show that the mutual influence between the itinerant electrons and the local magnetic moments is responsible for several phase transitions of the half-metals, namely first and second order magnetic phase transitions, as well as half-metal to semiconductor and half-metal to semimetal transitions.Comment: 10 pages, 5 figures, submitted to Journal of Physics: Condensed Matte

The Poincare' coset models ISO(d-1,1)/R^n and T-duality

We generalize a family of Lagrangians with values in the Poincar\'e group ISO(d-1,1), which contain the description of spinning strings in flat (d-1)+1 dimensions, by including symmetric terms in the world-sheet coordinates. Then, by promoting a subgroup H=R^n, n less than or equal to d, which acts invariantly from the left on the element of ISO(d-1,1), to a gauge symmetry of the action, we obtain a family of sigma-models. They describe bosonic strings moving in (generally) curved, and in some cases degenerate, space-times with an axion field. Further, the space-times of the effective theory admit in general T-dual geometries. We give explicit results for two non degenerate cases.Comment: LaTeX, 24 pages, no figure

Determinants of knowledge about dietary supplements among Polish Internet users with no medical education: a nationwide cross-sectional study

BACKGROUND: Having an accurate understanding of dietary supplements is a prerequisite for informed decision regarding their intake. However, there is a need for studies of such understanding among the public based on validated research tools. OBJECTIVE: To assess the knowledge about dietary supplements in Polish Internet users with no medical education, to identify its determinants and design an appropriate predictive model. METHODS: The study protocol with statistical analysis plan was prospectively registered. Polish users of an online health service and a social networking service were administered a survey consisting of the recently-developed Questionnaire on Knowledge about Dietary Supplements, Questionnaire on Trust in Advertising Dietary Supplements, Beliefs about Medicines Questionnaire, as well as several other health related single-item measures and sociodemographic questions. The results were subjected to general linear modeling. RESULTS: In total, 6273 participants were included. Out of 17 yes/no questions in the Questionnaire of Knowledge about Dietary Supplements, the mean number of correct responses was 9.0 (95% CI: 8.9 to 9.1). Health service users performed worse than social networking ones by 2.3 (95% CI: 2.1 to 2.5) points in an analysis adjusted for potential confounders. Internet users had less true beliefs about dietary supplements if they presented higher trust in their advertising (adjusted β: -.37, 95% CI: -.39 to -.34), used dietary supplements (adjusted β: -.14, 95% CI: -.17 to -.12), experienced their positive effect (adjusted β: -.16, 95% CI: -.18 to -.13), were older or younger than 35 (adjusted β: -.14, 95% CI: -.17 to -.12), expressed interest in the topic of dietary supplements (adjusted β: -.10, 95% CI: -.13 to -.08), reported getting information about the products from friends (adjusted β: -.13, 95% CI: -.15 to -.11), believed that medicines are harmful (adjusted β: -.12, 95% CI: -.15 to -.10). The proposed 5-predictor model could explain 31.2% of variance in knowledge about dietary supplements. The model appeared resistant to overfitting and was able to forecast the majority of the observed associations. CONCLUSIONS: Polish Internet users with no medical education exhibit some false beliefs regarding dietary supplements. Trusting in advertising dietary supplements appears in conflict with having knowledge about them. There is an urgent need for effective online educational campaigns about dietary supplements and promotion of advertising literacy. The proposed predictive model, after being externally validated, may help identify the least informed target audience. CLINICALTRIAL: Open Science Framework, https://osf.io/5e92d/

Radiation and shielding study for the International Ultraviolet Explorer

Technical advisory services to ensure integrity of parts and material exposed to energetic particle radiation for the IUE scientific instruments, spacecraft, and subsystems are provided. A significant potential for interference, degradation, or failure for unprotected or sensitive items was found. Vulnerable items were identified, and appropriate tests, changes, and shields were defined