15,326 research outputs found

    Encurralados na pandemia de COVID-19: o efeito da preocupação com o risco e das emoções no burnout nos profissionais de saúde

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    The COVID-19 pandemic poses critical challenges for the health care workers (HCWs) around the world due to the increasing demands imposed on health care systems. This study aims to investigate how risk concern impacts burnout via positive and negative affect. Further, the moderating role of risk exposure (low, medium, and high) in this parallel mediation model is examined. A sample of 257 Portuguese HCWs answered a questionnaire. Structural equation modeling (SEM) analysis was applied. Results showed that risk concern positively influences negative affect – but not positive affect – and, consequently, burnout. Contrary to our expectations, this indirect effect was not greater for individuals in the high-risk group (vs. low-risk group), which can be explained by individual and organizational factors' buffering role. These findings draw healthcare organizations' attention to the hazardous effects of risk concern on HCWs' well-being.info:eu-repo/semantics/publishedVersio

    The redshift and broad band spectral energy distribution of NRAO 150

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    Context. NRAO 150 is one of the brightest radio and mm AGN sources on the northern sky. It has been revealed as an interesting source where to study extreme relativistic jet phenomena. However, its cosmological distance has not been reported so far, because of its optical faintness produced by strong Galactic extinction. Aims. Aiming at measuring the redshift of NRAO 150, and hence to start making possible quantitative studies from the source. Methods. We have conducted spectroscopic and photometric observations of the source in the near-IR, as well as in the optical. Results. All such observations have been successful in detecting the source. The near-IR spectroscopic observations reveal strong Hα\alpha and Hβ\beta emission lines from which the cosmological redshift of NRAO 150 (z=1.517±0.002z=1.517\pm0.002) has been determined for the first time. We classify the source as a flat-spectrum radio-loud quasar, for which we estimate a large super-massive black-hole mass ∼5×109M⊙\sim5\times 10^{9} \mathrm{M_\odot}. After extinction correction, the new near-IR and optical data have revealed a high-luminosity continuum-emission excess in the optical (peaking at ∼2000\sim2000\,\AA, rest frame) that we attribute to thermal emission from the accretion disk for which we estimate a high accretion rate, ∼30\sim30\,% of the Eddington limit. Conclusions. Comparison of these source properties, and its broad-band spectral-energy distribution, with those of Fermi blazars allow us to predict that NRAO 150 is among the most powerful blazars, and hence a high luminosity -although not detected yet- γ\gamma-ray emitter.Comment: 8 pages, 4 figure

    A queima-do-broto da soja.

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    Alternate islands of multiple isochronous chains in wave-particle interactions

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    We analyze the dynamics of a relativistic particle moving in a uniform magnetic field and perturbed by a standing electrostatic wave. We show that a pulsed wave produces an infinite number of perturbative terms with the same winding number, which may generate islands in the same region of phase space. As a consequence, the number of isochronous island chains varies as a function of the wave parameters. We observe that in all the resonances, the number of chains is related to the amplitude of the various resonant terms. We determine analytically the position of the periodic points and the number of island chains as a function of the wave number and wave period. Such information is very important when one is concerned with regular particle acceleration, since it is necessary to adjust the initial conditions of the particle to obtain the maximum acceleration.Comment: Submitte

    Living bacteria rheology: population growth, aggregation patterns and cooperative behaviour under different shear flows

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    The activity of growing living bacteria was investigated using real-time and in situ rheology -- in stationary and oscillatory shear. Two different strains of the human pathogen Staphylococcus aureus -- strain COL and its isogenic cell wall autolysis mutant -- were considered in this work. For low bacteria density, strain COL forms small clusters, while the mutant, presenting deficient cell separation, forms irregular larger aggregates. In the early stages of growth, when subjected to a stationary shear, the viscosity of both strains increases with the population of cells. As the bacteria reach the exponential phase of growth, the viscosity of the two strains follow different and rich behaviours, with no counterpart in the optical density or in the population's colony forming units measurements. While the viscosity of strain COL keeps increasing during the exponential phase and returns close to its initial value for the late phase of growth, where the population stabilizes, the viscosity of the mutant strain decreases steeply, still in the exponential phase, remains constant for some time and increases again, reaching a constant plateau at a maximum value for the late phase of growth. These complex viscoelastic behaviours, which were observed to be shear stress dependent, are a consequence of two coupled effects: the cell density continuous increase and its changing interacting properties. The viscous and elastic moduli of strain COL, obtained with oscillatory shear, exhibit power-law behaviours whose exponent are dependent on the bacteria growth stage. The viscous and elastic moduli of the mutant have complex behaviours, emerging from the different relaxation times that are associated with the large molecules of the medium and the self-organized structures of bacteria. These behaviours reflect nevertheless the bacteria growth stage.Comment: 9 pages, 10 figure

    Nonadiabatic coherent evolution of two-level systems under spontaneous decay

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    In this paper we extend current perspectives in engineering reservoirs by producing a time-dependent master equation leading to a nonstationary superposition equilibrium state that can be nonadiabatically controlled by the system-reservoir parameters. Working with an ion trapped inside a nonindeal cavity we first engineer effective Hamiltonians that couple the electronic states of the ion with the cavity mode. Subsequently, two classes of decoherence-free evolution of the superposition of the ground and decaying excited levels are achieved: those with time-dependent azimuthal or polar angle. As an application, we generalise the purpose of an earlier study [Phys. Rev. Lett. 96, 150403 (2006)], showing how to observe the geometric phases acquired by the protected nonstationary states even under a nonadiabatic evolution.Comment: 5 pages, no figure

    Are Anti-Ro52 Antibodies Associated with Pulmonary Involvement in Scleroderma?

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    Abstract Introduction: The presence of anti-Ro52 antibodies has been reported in a wide variety of autoimmune diseases, particularly in myositis, scleroderma and autoimmune liver diseases. Clinical significance of anti-Ro52 antibodies remains controversial. Studies are lacking in clarifying the association of anti-Ro52 with pulmonary involvement in scleroderma. Objectives: To determine if anti-Ro52 antibodies are associated with pulmonary involvement (interstitial, indirect pulmonary hypertension, or both) in scleroderma. Methods: Single center, retrospective study based on immunoblotting panel analysis and patients clinical records. Pulmonary manifestations were sub-grouped in: 1) interstitial (alveolitis and/or fibrosis), 2) pulmonary artery systolic pressure (PASP) ≥40 mmHg plus interstitial pulmonary disease, and 3) isolated PASP≥40 mmHg (purely vascular). Results: Our scleroderma cohort included 200 patients, of which 137 had immunoblotting panels with anti-Ro52 reactivity analysis. The search was conducted between January 2010 and July 2011. The frequency of pulmonary manifestations in patients with positive anti-Ro52 antibodies was 67.7% (n=31), and 60% (n=24) in the negative anti-Ro52 group, showing no significant differences between groups (p=0.621). Still no significant differences were found when pulmonary manifestations were evaluated according to the subgroups (p=0.525). Sensitivity, specificity, positive and negative predictive values of anti-Ro52 reactivity for determining pulmonary involvement in scleroderma were low. Conclusion: No association was found between positive anti-Ro52 antibodies and pulmonary involvement in scleroderma
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