3,305 research outputs found

    XMM-Newton Large Program on SN1006 - II: Thermal Emission

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    Based on the XMM-Newton large program on SN1006 and our newly developed spatially resolved spectroscopy tools (Paper~I), we study the thermal emission from ISM and ejecta of SN1006 by analyzing the spectra extracted from 583 tessellated regions dominated by thermal emission. With some key improvements in spectral analysis as compared to Paper~I, we obtain much better spectral fitting results with less residuals. The spatial distributions of the thermal and ionization states of the ISM and ejecta show different features, which are consistent with a scenario that the ISM (ejecta) is heated and ionized by the forward (reverse) shock propagating outward (inward). Different elements have different spatial distributions and origins, with Ne mostly from the ISM, Si and S from the ejecta, and O and Mg from both ISM and ejecta. Fe L-shell lines are only detected in a small shell-like region SE to the center of SN1006, indicating that most of the Fe-rich ejecta has not yet or just recently been reached by the reverse shock. The overall ejecta abundance patterns for most of the heavy elements, except for Fe and sometimes S, are consistent with typical Type~Ia SN products. The NW half of the SNR interior probably represents a region with turbulently mixed ISM and ejecta, so has enhanced emission from O, Mg, Si, S, lower ejecta temperature, and a large diversity of ionization age. In addition to the asymmetric ISM distribution, an asymmetric explosion of the progenitor star is also needed to explain the asymmetric ejecta distribution.Comment: 9 pages, 7 figures, 1 table, MNRAS in pres

    XMM-Newton Large Program on SN1006 - I: Methods and Initial Results of Spatially-Resolved Spectroscopy

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    Based on our newly developed methods and the XMM-Newton large program of SN1006, we extract and analyze the spectra from 3596 tessellated regions of this SNR each with 0.3-8 keV counts >104>10^4. For the first time, we map out multiple physical parameters, such as the temperature (kTkT), electron density (nen_e), ionization parameter (netn_et), ionization age (tiont_{ion}), metal abundances, as well as the radio-to-X-ray slope (α\alpha) and cutoff frequency (νcutoff\nu_{cutoff}) of the synchrotron emission. We construct probability distribution functions of kTkT and netn_et, and model them with several Gaussians, in order to characterize the average thermal and ionization states of such an extended source. We construct equivalent width (EW) maps based on continuum interpolation with the spectral model of each regions. We then compare the EW maps of OVII, OVIII, OVII Kδζ\delta-\zeta, Ne, Mg, SiXIII, SiXIV, and S lines constructed with this method to those constructed with linear interpolation. We further extract spectra from larger regions to confirm the features revealed by parameter and EW maps, which are often not directly detectable on X-ray intensity images. For example, O abundance is consistent with solar across the SNR, except for a low-abundance hole in the center. This "O Hole" has enhanced OVII Kδζ\delta-\zeta and Fe emissions, indicating recently reverse shocked ejecta, but also has the highest netn_et, indicating forward shocked ISM. Therefore, a multi-temperature model is needed to decompose these components. The asymmetric metal distributions suggest there is either an asymmetric explosion of the SN or an asymmetric distribution of the ISM.Comment: 25 pages, 18 figures, 4 tables, MNRAS, in pres

    Which Motivational Behaviors Impact Success in a Clinical Anatomy Course for Entry Level Doctor of Physical Therapy Students?

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    Objectives: The motivational behavior of self-efficacy for learning and performance was correlated with academic success in Doctor of Physical Therapy (DPT) students taking clinical anatomy, the first foundational course in the program. Students’ motivation strategies have been reported to be important factors in academic success, however, these strategies have not been investigated in DPT students. Therefore, the purpose of this study was to determine if course grade in clinical anatomy was correlated with the motivation subscales of the Motivated Strategies for Learning Questionnaire (MSLQ).Materials and Methods: The MSLQ was administered to 33first-year DPT students who consented to participate in the study. Correlation (Pearson r zero order) between the subscales and final course grade in clinical anatomy were determined. Results: Self-efficacy for learning and performance was correlated with course grade (r(31)=.44, p \u3c.05), while intrinsic and extrinsic goal orientation, task value, control of learning beliefs, and test anxiety, were poorly correlated. Conclusions: The results of the current study, indicating that self-efficacy for learning and performance is correlated with academic success, could be utilized in DPT programs to broaden admission processes, and aid in the development of remedial curricular and teaching strategies to support students identified with poor self-efficacy for learning and performance

    Age, gender, and territory of COVID-19 infections and fatalities

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    In this note we explore the main demographic differentials in the spread and impact of COVID-19 paying special attention to the combined effect of age and gender, and to the differences at territorial level where population density plays a large role in the diffusion and outcome of the disease in terms of morbidity and mortality. The information is important for designing an exit strategy from COVID-19 and anticipating the rebound for certain segments of the population with differential medical needs, particularly those living in high-density locations.JRC.E.6-Demography, Migration and Governanc

    Multi-Wavelength Observations of the HBL Object 1ES 1011+496 in Spring 2008

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    In the spring of 2008 MAGIC organised multi-wavelength (MWL) observations of the blazar 1ES 1011+496. 1ES 1011+496 is a high-frequency peaked BL Lac object discovered at VHE gamma-rays by MAGIC in spring 2007 during an optical outburst reported by the Tuorla Blazar Monitoring Programme. MAGIC re-observed the source during the 2008 MWL campaign which also included the Mets\"ahovi, KVA, Swift and AGILE telescopes. This was the first MWL campaign on this source that also included VHE coverage. MAGIC observed 1ES 1011+496 from March 4th to May 24th 2008 for a total of 27.9 hours, of which 20 h remained after quality cuts. The observations resulted in a detection of the source a ~7 sigma significance level with a mean flux and spectral index similar to those during the discovery. Here we will present the results of the MAGIC observations of the source in combination with contemporaneous observations at other wavelengths (radio, optical, X-rays, high energy gamma-rays) and discuss their implications on the modelling of the spectral energy distribution.Comment: 4 pages, 5 figures, contribution to the 32nd ICRC, Beijing 201

    Surface-layer (S-layer) of Human and Animal Clostridium Difficile Strains and Their Behaviour in Adherence to Epithelial Cells and Intestinal Colonization

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    Clostridium difficile is a frequent cause of severe, recurrent post-antibiotic diarrhoea and pseudomembranous colitis. The surface layer (S-layer) is the predominant outer surface component of C. difficile which is involved in pathogen-host interactions critical to pathogenesis. In this study, we characterized the S-layer protein A (SIpA) of animal and human strains belonging to different PCR-ribotypes (PR) and compared the in vitro adherence and in vivo colonization properties of strains showing different SIpA variants. Since each SIpA variant has been recently associated with an S-layer cassette, we were able to deduce the cassette for each of our strains. In this study, an identity of 99-100% was found among the SIpA of isolates belonging to PR 012, 014/020, 045 and 078. One exception was the SIpA of a poultry isolate, PR 014/020, which showed 99% identity with that of strain 0160, another PR 014/020 which contains an S-layer cassette 6. Interestingly, this cassette has also been found in a PR 018 strain, an emerging virulent type currently predominant in Italy. Five other SIpA variants (v014/020a-e) were identified in strains PR 014/020. In vitro adherence assays and in vivo colonization experiments were performed on five PR 014/020 strains: human 1064 (v014/020e), human 4684/08 (v014/020b), human Ill 106 (v078a), poultry P30 (v014/020d) and poultry PB90 (v014/020b) strains. Adhesion assays indicate that C. difficile strains vary in their capacity to adhere to cells in culture and that adhesion seems to be independent of the SIpA variant. Colonization properties were assessed in vivo using a dixenic mouse model of colonization. The kinetics of faecal shedding and caecal colonization were similar when human 4684/08 (v014/020b) strain was compared with human 1064 (v014/020e) and poultry PB90 (v014/02013) strain. In contrast, poultry P30 (v014/020d) strain outcompeted both human 4684/08 (v014/020b) and IT1106 (v078a) strains and its adherence to caeca at day 7 was significantly higher. The peculiar characteristics of C. difficile P30 seem to advantage it in colonizing the intestinal mice niche, increasing its ability to compete and adapt. The results obtained underline the need of an increased attention to the genetic evolution of C. difficile to prevent and limit the consequences of the emergence of increasingly virulent strains

    The supernova remnant SN 1006 as a Galactic particle accelerator

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    The origin of cosmic rays is a pivotal open issue of high-energy astrophysics. Supernova remnants are strong candidates to be the Galactic factory of cosmic rays, their blast waves being powerful particle accelerators. However, super nova remnants can power the observed flux of cosmic rays only if they transfer a significant fraction of their kinetic energy to the accelerated particles, but conclusive evidence for such efficient acceleration is still lacking. In this sce nario, the shock energy channeled to cosmic rays should induce a higher post shock density than that predicted by standard shock conditions. Here we show this effect, and probe its dependence on the orientation of the ambient magnetic field, by analyzing deep X-ray observations of the Galactic remnant of SN 1006. By comparing our results with state-of-the-art models, we con clude that SN 1006 is an efficient source of cosmic rays and obtain an obser vational support for the quasi-parallel acceleration mechanism

    Foreword Special Issue on "New Simulation Methodologies for Next-Generation TCAD Tools"

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    Technology computer-aided design (TCAD) is an integral part of the development process of semiconductor technologies and devices, a field which has become increasingly complex and heterogeneous. Processing of integrated circuits requires nowadays over 400 process steps, and the resulting devices often have an intricate 3-D structure and contain various specifically designed materials. The full device behavior can only be understood by considering effects on all length scales from atomistic (material properties, interfaces, defects, and so on), to nanometric (quantum confinement, non-bulk properties, tunneling, ballistic transport, and so on), to full-chip dimensions (strain, heat transport, and so on), and time scales from femtoseconds (scattering, ferroelectric switching time, and so on) to seconds (trapping times, degradation, and so on). Voltages, currents, and charges have been scaled to such low levels that statistical effects and process variations have a strong impact. Devices based on new materials (e.g., 2-D crystals) and physical principles (ferroelectrics, magnetic materials, qubits, and so on) challenge standard TCAD approaches. While the simulation methods developed by the physics community can describe the basic device behavior, they often lack important simulation capabilities like, for example, transient simulations or integration with other TCAD tools, and are often too slow for daily use. Due to the complexity of semiconductor technology, it becomes more and more difficult to assess the impact of a change in processing or device structure on circuit performance by looking at a single aspect of an isolated device under idealized conditions. Instead, a TCAD tool chain is required which can handle realistic device structures embedded in a chip environment. New methodologies are required for all aspects of TCAD to ensure an efficient tool chain covering from atomistic effects to circuit behavior based on flexible simulation models that can handle new materials, device principles, and the ensuing large-scale simulations and that make use of artificial intelligence for well-chosen (sub)routines to decrease the overall simulation time. This Special Issue features six invited and 18 regular papers that address these problems
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