5,239 research outputs found

    The Spectral Energy Distribution of the High-Z Blazar Q0906+693

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    We describe further observations of QSO J0906+6930, a z=5.48 blazar likely to be detected in gamma-rays. New radio and X-ray data place significant constraints on any kpc-scale extension of the VLBA-detected jet. Improved optical spectroscopy detects absorption from an intervening galaxy at z=1.849 and raise the possibility that this distant, bright source is lensed. We combine the new data into an improved SED for the blazar core and comment on the Compton keV-GeV flux component.Comment: 10pp, 3 figures, accpeted for publication in the Astronomical Journa

    A multi-class approach for ranking graph nodes: models and experiments with incomplete data

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    After the phenomenal success of the PageRank algorithm, many researchers have extended the PageRank approach to ranking graphs with richer structures beside the simple linkage structure. In some scenarios we have to deal with multi-parameters data where each node has additional features and there are relationships between such features. This paper stems from the need of a systematic approach when dealing with multi-parameter data. We propose models and ranking algorithms which can be used with little adjustments for a large variety of networks (bibliographic data, patent data, twitter and social data, healthcare data). In this paper we focus on several aspects which have not been addressed in the literature: (1) we propose different models for ranking multi-parameters data and a class of numerical algorithms for efficiently computing the ranking score of such models, (2) by analyzing the stability and convergence properties of the numerical schemes we tune a fast and stable technique for the ranking problem, (3) we consider the issue of the robustness of our models when data are incomplete. The comparison of the rank on the incomplete data with the rank on the full structure shows that our models compute consistent rankings whose correlation is up to 60% when just 10% of the links of the attributes are maintained suggesting the suitability of our model also when the data are incomplete

    Fitting Pulsar Wind Tori. II. Error Analysis and Applications

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    We have applied the torus fitting procedure described in Ng & Romani (2004) to PWNe observations in the Chandra data archive. This study provides quantitative measurement of the PWN geometry and we characterize the uncertainties in the fits, with statistical errors coming from the fit uncertainties and systematic errors estimated by varying the assumed fitting model. The symmetry axis Ψ\Psi of the PWN are generally well determined, and highly model-independent. We often derive a robust value for the spin inclination ζ\zeta. We briefly discuss the utility of these results in comparison with new radio and high energy pulse measurementsComment: 15 pages, 3 figures, ApJ in pres

    First Astronomical Application of a Cryogenic TES Spectrophotometer

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    We report on the first astronomical observations with a photon counting pixel detector that provides arrival time- (delta t = 100ns) and energy- (delta E_gamma < 0.15eV) resolved measurements from the near IR through the near UV. Our test observations were performed by coupling this Transition Edge Sensor (TES) device to a 0.6m telescope; we have obtained the first simultaneous optical near-IR phase-resolved spectra of the Crab pulsar. A varying infrared turnover gives evidence of self-absorption in the pulsar plasma. The potential of such detectors in imaging arrays from a space platform are briefly described.Comment: 4 pages, 5 figure

    Burnout among physicians

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    Burnout is a common syndrome seen in healthcare workers, particularly physicians who are exposed to a high level of stress at work; it includes emotional exhaustion, depersonalization, and low personal accomplishment. Burnout among physicians has garnered significant attention because of the negative impact it renders on patient care and medical personnel. Physicians who had high burnout levels reportedly committed more medical errors. Stress management programs that range from relaxation to cognitive-behavioral and patientcentered therapy have been found to be of utmost significance when it comes to preventing and treating burnout. However, evidence is insufficient to support that stress management programs can help reducing jobrelated stress beyond the intervention period, and similarly mindfulness-based stress reduction interventions efficiently reduce psychological distress and negative vibes, and encourage empathy while significantly enhancing physicians’ quality of life. On the other hand, a few small studies have suggested that Balint sessions can have a promising positive effect in preventing burnout; moreover exercises can reduce anxiety levels and exhaustion symptoms while improving the mental and physical well-being of healthcare workers. Occupational interventions in the work settings can also improve the emotional and work-induced exhaustion. Combining both individual and organizational interventions can have a good impact in reducing burnout scores among physicians; therefore, multidisciplinary actions that include changes in the work environmental factors along with stress management programs that teach people how to cope better with stressful events showed promising solutions to manage burnout. However, until now there have been no rigorous studies to prove this. More interventional research targeting medical students, residents, and practicing physicians are needed in order to improve psychological well-being, professional careers, as well as the quality of care provided to patients.Keywords: burnout; health care professionals; stress management; mindfulness-based stress reduction programs; physicians well-bein

    Blazar Counterparts for 3EG Sources at -40 < decl. < 0: Pushing South Through the Bulge

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    Supplementing existing survey data with VLA observations, we have extended γ\gamma-ray counterpart identifications down to decl. = -40^\circ using our Figure of Merit approach. We find blazar counterparts for \sim 70% of EGRET sources above decl. = -40^\circ away from the Galaxy. Spectroscopic confirmation is in progress, and spectra for \sim two dozen sources are presented here. We find evidence that increased exposure in the bulge region allowed EGRET to detect relatively faint blazars; a clear excess of non-blazar objects in this region however argues for an additional (new) source class.Comment: ApJ accepte
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