Aims. Our goal is to study the different morphologies associated to the interaction of the stellar winds of AGB stars and red supergiants with the interstellar medium (ISM) to follow the fate of the ...circumstellar matter injected into the interstellar medium. Methods. Far-infrared Herschel/PACS images at 70 and 160 μm of a sample of 78 Galactic evolved stars are used to study the (dust) emission structures developing out of stellar wind-ISM interaction. In addition, two-fluid hydrodynamical simulations of the coupled gas and dust in wind-ISM interactions are used for comparison with the observations. Results. Four distinct classes of wind-ISM interaction (i.e. “fermata”, “eyes”, “irregular”, and “rings”) are identified, and basic parameters affecting the morphology are discussed. We detect bow shocks for ~40% of the sample and detached rings for ~20%. The total dust and gas mass inferred from the observed infrared emission is similar to the stellar mass loss over a period of a few thousand years, while in most cases it is less than the total ISM mass potentially swept-up by the wind-ISM interaction. De-projected stand-off distances (R0) – defined as the distance between the central star and the nearest point of the interaction region – of the detected bow shocks (“fermata” and “eyes”) are derived from the PACS images and compared to previous results, model predictions, and the simulations. All observed bow shocks have stand-off distances smaller than 1 pc. Observed and theoretical stand-off distances are used together to independently derive the local ISM density. Conclusions. Both theoretical (analytical) models and hydrodynamical simulations give stand-off distances for adopted stellar properties that are in good agreement with the measured de-projected stand-off distance of wind-ISM bow shocks. The possible detection of a bow shock – for the distance-limited sample – appears to be governed by its physical size as set roughly by the stand-off distance. In particular the star’s peculiar space velocity and the density of the ISM appear decisive in detecting emission from bow shocks or detached rings. In most cases the derived ISM densities concur with those typical of the warm neutral and ionised gas in the Galaxy, though some cases point towards the presence of cold diffuse clouds. Tentatively, the “eyes” class objects are associated to (visual) binaries, while the “rings” generally do not appear to occur for M-type stars, only for C or S-type objects that have experienced a thermal pulse.
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Aims. The spatial structure of the emission lines and continuum over the 50″ extent of the nearby, O-rich, PN NGC 7009 (Saturn Nebula) have been observed with the MUSE integral field spectrograph on ...the ESO Very Large Telescope. This study concentrates on maps of line emission and their interpretation in terms of physical conditions. Methods. MUSE Science Verification data, in <0.6″ seeing, have been reduced and analysed as maps of emission lines and continuum over the wavelength range 4750–9350 Å. The dust extinction, the electron densities and temperatures of various phases of the ionized gas, abundances of species from low to high ionization and some total abundances are determined using standard techniques. Results. Emission line maps over the bright shells are presented, from neutral to the highest ionization available (He II and Mn V). For collisionally excited lines (CELs), maps of electron temperature (Te from N II and S III) and density (Ne from S II and Cl III) are available and for optical recombination lines (ORLs) temperature (from the Paschen jump and ratio of He I lines) and density (from high Paschen lines). These estimates are compared: for the first time, maps of the differences in CEL and ORL Te’s have been derived, and correspondingly a map of t2 between a CEL and ORL temperature, showing considerable detail. Total abundances of only He and O were formed, the latter using three ionization correction factors. However, the map of He/H is not flat, departing by ~2% from a constant value, with remnants corresponding to ionization structures. An integrated spectrum over an area of 2340 arcsec2 was also formed and compared to 1D photoionization models. Conclusions. The spatial variation of a range of nebular parameters illustrates the complexity of the ionized media in NGC 7009. These MUSE data are very rich with detections of hundreds of lines over areas of hundreds of arcsec2 and follow-on studies are outlined.
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Context. Dust plays a significant role in planetary nebulae. Dust ejected with the gas in the asymptotic giant branch (AGB) phase is subject to the harsh environment of the planetary nebula (PN) ...while the star is evolving towards a white dwarf. Dust surviving the PN phase contributes to the dust content of the interstellar medium. Aims. The morphology of the internal dust extinction has been mapped for the first time in a PN, the bright nearby Galactic nebula NGC 7009. The morphologies of the gas, dust extinction and dust-to-gas ratio are compared to the structural features of the nebula. Methods. Emission line maps in H Balmer and Paschen lines were formed from analysis of MUSE cubes of NGC 7009 observed during science verification of the instrument. The measured electron temperature and density from the same cube were employed to predict the theoretical H line ratios and derive the extinction distribution across the nebula. After correction for the interstellar extinction to NGC 7009, the internal AV/NH has been mapped for the first time in a PN. Results. The extinction map of NGC 7009 has considerable structure, broadly corresponding to the morphological features of the nebula. The dust-to-gas ratio, AV/NH, increases from 0.7 times the interstellar value to >5 times from the centre towards the periphery of the ionized nebula. The integrated AV/NH is about 2× the mean ISM value. A large-scale feature in the extinction map is a wave, consisting of a crest and trough, at the rim of the inner shell. The nature of this feature is investigated and instrumental and physical causes considered; no convincing mechanisms were identified to produce this feature, other than AGB mass loss variations. Conclusions. Extinction mapping from H emission line imaging of PNe with MUSE provides a powerful tool for revealing the properties of internal dust and the dust-to-gas ratio.
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Simulation of power converters has traditionally been carried out using simplified models to shorten simulation time. This will compromise the accuracy of the results. A proposed fast simulation ...method for simulating converter losses and device temperatures over long mission profiles (load cycles) is described in this paper. It utilizes accurate physics-based models for the device losses, and is validated with experimentally obtained results.
A retrospective, consecutive case series.
The relationship between dysphagia and acute cervical spinal cord injury (CSCI) has been recently reported; however, the cause and mechanism of dysphagia are ...still not well understood. No definitive factors have yet been established according to multivariate analysis. The objective is to elucidate the incidence and risk factors of dysphagia in patients with acute CSCI.
Spinal Injuries Center, Fukuoka, Japan.
A total of 298 patients with acute CSCI, who were evaluated for neurological impairment within 3 days after injury, were reviewed. CSCI patients with tube dependence due to obvious aspiration after injury were defined as having dysphagia. The factors postulated to increase the risk for dysphagia, including the patient's age, sex, American Spinal Injury Association (ASIA) impairment scale at 3 days after injury, level of injury, tracheostomy and operative treatment, were analyzed using a multiple logistic regression model.
Of 298 patients, 21 were suffering from severe dysphagia after acute CSCI (7.0%). Of these 21 patients, 12 (57%) had CSCI at the C3-C4 level. Multivariable logistic regression analysis revealed that old age (>72 years), severe ASIA impairment scale (A or B) and presence of tracheostomy were significant risk factors of dysphagia. Level of injury ⩾C3-C4 was not a significant risk factor after adjustment for several potential confounders.
The incidence of severe dysphagia associated with aspiration was 7%. Old age, severe paralysis and presence of tracheostomy may be the risk factors for dysphagia. The risk for dysphagia should be evaluated to prevent aspiration pneumonia.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
To evaluate the possible causative role of central serous chorioretinopathy (CSC) in the development of exudative age-related macular degeneration (AMD).
In a cross-sectional study at an ...institutional setting, 150 control subjects who had senile cataract or nasolacrimal duct stenosis and who were older than 50 years were enrolled. The background data for 89 patients with typical AMD (tAMD) and 138 patients with polypoidal choroidal vasculopathy (PCV) were used for comparison. Their medical records were taken for history of CSC, hypertension, systemic steroid use, and smoking. The fundus was also evaluated for signs of atrophic retinal pigment epithelial (RPE) tract and for focal photocoagulation scars in the macula.
After adjusting for age, gender, and history of hypertension, systemic steroid use, and smoking, history of CSC was significantly more frequent (P<0.0001) in patients with PCV (15 patients, 10.9%) compared with patients with tAMD (2 patients, 2.2%) or control subjects (0 patients). On fundoscopy, an atrophic RPE tract (seven patients) or a focal photocoagulation scar (one patient) was observed only in patients with PCV (eight patients, 5.8%), and the frequency was statistically significant compared with that with tAMD (P=0.0143) or control subjects (P=0.0143). The laterality of CSC and AMD involved the same eye in 9 of 10 patients among those who had unilateral AMD and a reported unilateral CSC history.
A history of CSC may be a predisposing factor for the development of PCV in the Japanese population.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
This paper describes the development and implementation of an analytical 3-D thermal model for fast and accurate thermal simulation of power device modules in electrothermal converter simulation. A ...Fourier-based solution is used to solve the 3-D heat equation. The solution can describe the variation of temperature through the whole inverter power module structure as a function of time. The model can simulate thermal interactions resulting from multiple heat sources. The thermal model is extremely fast to simulate compared to finite-element (FEM) approaches. The new model has been implemented in MATLAB/Simulink in order to cosimulate with the converter model which is in the same form. The model has been validated against the computational fluid dynamics (CFD) software package FLOTHERM and shows good agreement. The required aspects of 3-D heat diffusion are captured successfully by the Fourier-based model.
Context. The detected variety in chemistry and circumstellar shell morphology of the limited sample of Galactic post-asymptotic giant branch (AGB) stars is so large that there is no consensus yet on ...how the different objects are linked by evolutionary channels. The evaluation is complicated by the fact that their distances and hence luminosities remain largely unknown. Aims. We construct a catalogue of the optically bright post-AGB stars in the Large Magellanic Cloud (LMC). The sample forms an ideal testbed for stellar evolution theory predictions of the final phase of low- and intermediate-mass stars, because the distance and hence luminosity and also the current and initial mass of these objects is well constrained. Methods. Via cross-correlation of the Spitzer SAGE catalogue with optical catalogues we selected a sample of LMC post-AGB candidates based on their 8 − 24 colour index and estimated luminosity. We determined the fundamental properties of the central stars of 105 of these objects using low-resolution, optical spectra that we obtained at Siding Spring Observatory and SAAO. Results. We constructed a catalogue of 70 high probability and 1337 candidate post-AGB stars that is available at the CDS. About half of the objects in our sample of post-AGB candidates show a spectral energy distribution (SED) that is indicative of a disc rather than an expanding and cooling AGB remnant. Like in the Galaxy, the disc sources are likely associated with binary evolution. Important side products of this research are catalogues of candidate young stellar objects, candidate supergiants with circumstellar dust, and discarded objects for which a spectrum was obtained. These too are available at the CDS.
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We present X-ray spectral analysis of 20 point-like X-ray sources detected in Chandra Planetary Nebula Survey observations of 59 planetary nebulae (PNe) in the solar neighborhood. Most of these 20 ...detections are associated with luminous central stars within relatively young, compact nebulae. The vast majority of these point-like X-ray-emitting sources at PN cores display relatively "hard" (> or =, slanted0.5 keV) X-ray emission components that are unlikely to be due to photospheric emission from the hot central stars (CSPN). Instead, we demonstrate that these sources are well modeled by optically thin thermal plasmas. From the plasma properties, we identify two classes of CSPN X-ray emission: (1) high-temperature plasmas with X-ray luminosities, LX, that appear uncorrelated with the CSPN bolometric luminosity, L sub(bol) and (2) lower-temperature plasmas with L sub(X)/L sub(bol) ~ 10 super(-7). We suggest these two classes correspond to the physical processes of magnetically active binary companions and self-shocking stellar winds, respectively. In many cases this conclusion is supported by corroborative multiwavelength evidence for the wind and binary properties of the PN central stars. By thus honing in on the origins of X-ray emission from PN central stars, we enhance the ability of CSPN X-ray sources to constrain models of PN shaping that invoke wind interactions and binarity.
A multicenter prospective study comparing the neurological outcome of patients treated by surgical intervention versus conservative treatment for cervical spinal cord injury (CSCI) without bone and ...disc injury.
To evaluate the neurological outcome of decompression surgery for CSCI without bone and disc injury in patients with spinal cord compression with incomplete paralysis (AIS B, C).
The Japan LHWO Spinal Injuries Center and the other 10 labor accident hospitals in Japan.
Thirty-four patients with AIS B, C and cervical spinal cord compression were classified into either a surgical treatment group or a conservative treatment group. The 34 patients enrolled were equally divided between the groups. Patients with AIS B, C and mild spinal compression were enrolled into another group.
The neurological outcome of surgical treatment and conservative treatment for AIS B, C with spinal cord compression was found to be closely similar. In addition, the neurological outcome was also similar to that observed after conservative treatment for AIS B, C in patients presenting with mild spinal cord compression.
Surgical treatment was not found to be superior to conservative treatment for CSCI patients without bone and disc injury suffering from spinal cord compression in the acute phase.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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