37 resultados para hot subdwarf stars

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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Hot Jupiters, due to the proximity to their parent stars, are subjected to a strong irradiating flux that governs their radiative and dynamical properties. We compute a suite of three-dimensional circulation models with dual-band radiative transfer, exploring a relevant range of irradiation temperatures, both with and without temperature inversions. We find that, for irradiation temperatures T irr lsim 2000 K, heat redistribution is very efficient, producing comparable dayside and nightside fluxes. For T irr ≈ 2200-2400 K, the redistribution starts to break down, resulting in a high day-night flux contrast. Our simulations indicate that the efficiency of redistribution is primarily governed by the ratio of advective to radiative timescales. Models with temperature inversions display a higher day-night contrast due to the deposition of starlight at higher altitudes, but we find this opacity-driven effect to be secondary compared to the effects of irradiation. The hotspot offset from the substellar point is large when insolation is weak and redistribution is efficient, and decreases as redistribution breaks down. The atmospheric flow can be potentially subjected to the Kelvin-Helmholtz instability (as indicated by the Richardson number) only in the uppermost layers, with a depth that penetrates down to pressures of a few millibars at most. Shocks penetrate deeper, down to several bars in the hottest model. Ohmic dissipation generally occurs down to deeper levels than shock dissipation (to tens of bars), but the penetration depth varies with the atmospheric opacity. The total dissipated Ohmic power increases steeply with the strength of the irradiating flux and the dissipation depth recedes into the atmosphere, favoring radius inflation in the most irradiated objects. A survey of the existing data, as well as the inferences made from them, reveals that our results are broadly consistent with the observational trends.

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Code duplication is common in current programming-practice: programmers search for snippets of code, incorporate them into their projects and then modify them to their needs. In today's practice, no automated scheme is in place to inform both parties of any distant changes of the code. As code snippets continues to evolve both on the side of the user and on the side of the author, both may wish to benefit from remote bug fixes or refinements --- authors may be interested in the actual usage of their code snippets, and researchers could gather information on clone usage. We propose maintaining a link between software clones across repositories and outline how the links can be created and maintained.

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Free-living amoebae (FLA) belonging to Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris, and Sappinia pedata are known to cause infections in humans and animals leading to severe brain pathologies. Worldwide, warm aquatic environments have been found to be suitable habitats for pathogenic FLA. The present study reports on screening for potentially pathogenic FLA in four hot spring resorts in Switzerland. Water samples were taken from water filtration units and from the pools, respectively. Amoebae isolated from samples taken during, or before, the filtration process were demonstrated to be morphologically and phylogenetically related to Stenoamoeba sp., Hartmannella vermiformis, Echinamoeba exundans, and Acanthamoeba healyi. With regard to the swimming pools, FLA were isolated only in one resort, and the isolate was identified as non-pathogenic and as related to E. exundans. Further investigations showed that the isolates morphologically and phylogenetically related to A. healyi displayed a pronounced thermotolerance, and exhibited a marked in vitro cytotoxicity upon 5-day exposure to murine L929 fibroblasts. Experimental intranasal infection of Rag2-immunodeficient mice with these isolates led to severe brain pathologies, and viable trophozoites were isolated from the nasal mucosa, brain tissue, and lungs post mortem. In summary, isolates related to A. healyi were suggestive of being potentially pathogenic to immunocompromised persons. However, the presence of these isolates was limited to the filtration units, and an effective threat for health can therefore be excluded.

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Atrial fibrillation (AF) ablation has evolved to the treatment of choice for patients with drug-resistant and symptomatic AF. Pulmonary vein isolation at the ostial or antral level usually is sufficient for treatment of true paroxysmal AF. For persistent AF ablation, drivers and perpetuators outside of the pulmonary veins are responsible for AF maintenance and have to be targeted to achieve satisfying arrhythmia-free success rate. Both complex fractionated atrial electrogram (CFAE) ablation and linear ablation are added to pulmonary vein isolation for persistent AF ablation. Nevertheless, ablation failure and necessity of repeat ablations are still frequent, especially after persistent AF ablation. Pulmonary vein reconduction is the main reason for arrhythmia recurrence after paroxysmal and to a lesser extent after persistent AF ablation. Failure of persistent AF ablation mostly is a consequence of inadequate trigger ablation, substrate modification or incompletely ablated or reconducting linear lesions. In this review we will discuss these points responsible for AF recurrence after ablation and review current possibilities on how to overcome these limitations.

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OBJECTIVE: The aim of this study was to evaluate the feasibility of a clinical trial investigating the effects of acupuncture (AP) and Chinese herbal medicine (CHM) on hot flushes and quality of life in postmenopausal women. METHODS: Forty postmenopausal women reporting at least 20 hot flushes per week were enrolled in a randomized controlled trial. They were randomly allocated to receive traditional Chinese medicine (TCM) AP, sham AP, verum CHM, or placebo CHM for 12 weeks. Follow-up assessment was conducted 12 weeks after intervention. Primary outcome measures included hot flush frequency and severity. As a secondary outcome measure, the severity of menopausal symptoms was assessed using the Menopause Rating Scale (MRS) II. RESULTS: TCM AP induced a significant decline in all outcome measures from pretreatment to posttreatment compared with sham AP (hot flush frequency, P = 0.016; hot flush severity, P = 0.013; MRS, P < 0.001). In the TCM AP group, a larger decrease in MRS scores persisted from pretreatment to follow-up (P = 0.048). No significant differences were noted between the verum CHM group and the placebo CHM group. Compared with the verum CHM group, there was a significant decrease in MRS scores (P = 0.002) and a trend toward a stronger decrease in hot flush severity (P = 0.06) in the TCM AP group from pretreatment to posttreatment. CONCLUSIONS: TCM AP is superior to sham AP and verum CHM in reducing menopausal symptoms, whereas verum CHM shows no significant improvements when compared with placebo CHM.