3,833 research outputs found

    Dynamical Ne K Edge and Line Variations in the X-Ray Spectrum of the Ultra-compact Binary 4U 0614+091

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    We observed the ultra-compact binary candidate 4U 0614+091 for a total of 200 ksec with the high-energy transmission gratings onboard the \chandra X-ray Observatory. The source is found at various intensity levels with spectral variations present. X-ray luminosities vary between 2.0×1036\times10^{36} \ergsec and 3.5×1036\times10^{36} \ergsec. Continuum variations are present at all times and spectra can be well fit with a powerlaw component, a high kT blackbody component, and a broad line component near oxygen. The spectra require adjustments to the Ne K edge and in some occasions also to the Mg K edge. The Ne K edge appears variable in terms of optical depths and morphology. The edge reveals average blue- and red-shifted values implying Doppler velocities of the order of 3500 \kms. The data show that Ne K exhibits excess column densities of up to several 1018^{18} cm−2^{-2}. The variability proves that the excess is intrinsic to the source. The correponding disk velocities also imply an outer disk radius of the order of <109< 10^9 cm consistent with an ultra-compact binary nature. We also detect a prominent soft emission line complex near the \oviii Lα\alpha position which appears extremely broad and relativistic effects from near the innermost disk have to be included. Gravitationally broadened line fits also provide nearly edge-on angles of inclination between 86 and 89∘^{\circ}. The emissions appear consistent with an ionized disk with ionization parameters of the order of 104^4 at radii of a few 107^7 cm. The line wavelengths with respect to \oviiia\ are found variably blue-shifted indicating more complex inner disk dynamics.Comment: 24 pages, 8 figures, submitted to the Astrophyscial Main Journa

    A synthetic human Agouti-related protein-(83–132)-NH2 fragment is a potent inhibitor of melanocortin receptor function

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    AbstractChemical synthesis of Agouti proteins – Agouti and Agouti-related proteins – is complicated by their large size and by multiple cysteine residues located in the carboxyl terminal regions. Three human Agouti-related protein (AGRP) fragments, two of which correspond to a proposed endoprotease cleavage site between amino acids 82 and 83, were synthesized and tested for anti-melanotropic activity using Xenopus laevis dermal melanophores. Amino-terminal fragments AGRP(25–51) and (54–82) were devoid of significant antagonist activity, whereas the amidated carboxyl-terminal AGRP fragment (83–132)-NH2 was potently active with an inhibitory equilibrium dissociation constant (Ki) of 0.7 nM. The ability to synthesize functionally active AGRP should help unravel its role in the central nervous system and its unusual properties with respect to interaction with the melanocortin family of G-protein coupled receptors

    Enterobiliary Fistula as a Complication of Eosinophilic Gastroenteritis: a Case Report

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    Eosinophilic gasteroenteritis is an uncommon disease with variable clinical features characterized by eosinophilic infiltration. Clinical manifestations range from non-specific gastrointestinal complaints such as nausea, vomiting, crampy abdominal pain, and diarrhea to specific findings such as malabsorption, protein loosing enteropathy, luminal obstruction, eosinophilic ascites and effusion. We report here on a case of eosinophilic gastroenteritis causing enterobiliary fistula which is an extremely unusual complication

    Phase-resolved optical and X-ray spectroscopy of low-mass X-ray binary X1822-371

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    (Abridged) X1822-371 is the prototypical accretion disc corona X-ray source, a low-mass X-ray binary viewed at very high inclination, thereby allowing the disc structure and extended disc coronal regions to be visible. We study the structure of the accretion disc in X1822-371 by modelling the phase-resolved spectra both in optical and X-ray regime. We analyse high time resolution optical ESO/VLT spectra of X1822-371 to study the variability in the emission line profiles. In addition, we use data from XMM-Newton space observatory to study phase-resolved as well as high resolution X-ray spectra. We apply the Doppler tomography technique to reconstruct a map of the optical emission distribution in the system. We fit multi-component models to the X-ray spectra. We find that our results from both the optical and X-ray analysis can be explained with a model where the accretion disc has a thick rim in the region where the accretion stream impacts the disc. The behaviour of the H_beta line complex implies that some of the accreting matter creates an outburst around the accretion stream impact location and that the resulting outflow of matter moves both away from the accretion disc and towards the centre of the disc. Such behaviour can be explained by an almost isotropic outflow of matter from the accretion stream impact region. The optical emission lines of HeII 4686 and 5411 show double peaked profiles, typical for an accretion disc at high inclination. However, their velocities are slower than expected for an accretion disc in a system like X1822-371. This, combined with the fact that the HeII emission lines do not get eclipsed during the partial eclipse in the continuum, suggests that the line emission does not originate in the orbital plane and is more likely to come from above the accretion disc, for example the accretion disc wind.Comment: 10 pages, 13 figures, accepted for publication in A&

    Granulosa Cell Tumor of Scrotal Tunics: A Case Report

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    We report a case of adult granulosa cell tumor arising in the scrotal tunics. The patient was a 34-year-old man who presented with right scrotal swelling, first noticed four months previously. Under the initial clinical impression of epididymoorchitis, antibiotic treatment was instituted but there was no response. The paratesticular nodules revealed by ultrasound and magnetic resonance imaging mimicked intratesticular lesion, and radical orchiectomy was performed. Although several cases of adult testicular granulosa cell tumor, have been reported, the occurrence of this entity in the paratesticular area has not, as far as we are aware, been previously described

    3D-vision based detection, localization, and sizing of broccoli heads in the field

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    This paper describes a 3D vision system for robotic harvesting of broccoli using low-cost RGB-D sensors, which was developed and evaluated using sensory data collected under real-world field conditions in both the UK and Spain. The presented method addresses the tasks of detecting mature broccoli heads in the field and providing their 3D locations relative to the vehicle. The paper evaluates different 3D features, machine learning, and temporal filtering methods for detection of broccoli heads. Our experiments show that a combination of Viewpoint Feature Histograms, Support Vector Machine classifier, and a temporal filter to track the detected heads results in a system that detects broccoli heads with high precision. We also show that the temporal filtering can be used to generate a 3D map of the broccoli head positions in the field. Additionally, we present methods for automatically estimating the size of the broccoli heads, to determine when a head is ready for harvest. All of the methods were evaluated using ground-truth data from both the UK and Spain, which we also make available to the research community for subsequent algorithm development and result comparison. Cross-validation of the system trained on the UK dataset on the Spanish dataset, and vice versa, indicated good generalization capabilities of the system, confirming the strong potential of low-cost 3D imaging for commercial broccoli harvesting

    Experimental analysis of the effect of local base blowing on three-dimensional wake modes

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    Wake modes of a three-dimensional blunt-based body near a wall are investigated at a Reynolds number . The targeted modes are the static symmetry-breaking mode and two antisymmetric periodic modes. The static mode orientation is aligned with the horizontal major -axis of the base and randomly switches between a positive and a negative state leading to long-time bistable dynamics of the turbulent wake. The modifications of these modes are studied when continuous blowing is applied at different locations through four slits along the base edges (denoted L for left, R for right, T for top and B for bottom) in either four single asymmetric configurations or two double symmetric configurations (denoted LR and TB). Two regimes, referred to as mass and momentum, are clearly identifiable for all configurations. The mass regime, which is fairly insensitive to blowing momentum and location, is characterized by the growth of the recirculating bubble as the total injected flow rate is increased, and is associated with a base drag reduction and interpreted as resulting from the equilibrium between mass fluxes feeding and emptying the recirculating region. A simple budget model is shown to be in agreement with entrainment velocities measured for isolated turbulent mixing layers. The strength of the static mode is reduced up to 20 % when the bubble length is maximum, whereas no change in the periodic mode frequencies is found. On the other hand, the momentum regime is characterized by the deflating of the recirculating bubble, leading to base drag increase, and it is interpreted by the free shear layer forcing, which increases the entrainment velocity, thus emptying the recirculating bubble. In this regime the static mode orientation is imposed by the blowing symmetry. Lateral L and R (respectively top/bottom T and B) blowing configurations select or states in the horizontal (respectively vertical) direction, while bistable dynamics persists for the symmetric LR and TB configurations. The shape of periodic modes follows the changes in wake static orientation. The transition between the two regimes is governed by both the total injected flow rate and the location of the injection
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