2,376 research outputs found

    Firedec: a two-channel finite-resolution image deconvolution algorithm

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    We present a two-channel deconvolution method that decomposes images into a parametric point-source channel and a pixelized extended-source channel. Based on the central idea of the deconvolution algorithm proposed by Magain, Courbin & Sohy (1998), the method aims at improving the resolution of the data rather than at completely removing the point spread function (PSF). Improvements over the original method include a better regularization of the pixel channel of the image, based on wavelet filtering and multiscale analysis, and a better controlled separation of the point source vs. the extended source. In addition, the method is able to simultaneously deconvolve many individual frames of the same object taken with different instruments under different PSF conditions. For this purpose, we introduce a general geometric transformation between individual images. This transformation allows the combination of the images without having to interpolate them. We illustrate the capability of our algorithm using real and simulated images with complex diffraction-limited PSF.Comment: Accepted in A&A. An application of the technique to real data is available in Cantale et al. http://arxiv.org/abs/1601.05192v

    Holomorphic extension of smooth CR-mappings between real-analytic and real-algebraic CR-manifolds

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    We establish results on holomorphic extension of CR-mappings of class CC^\infty between a real-analytic CR-submanifold of \C^N and a real-algebraic CR-submanifold of \C^{N'}

    Genetic Abnormalities in a Calf with Congenital Increased Muscular Tonus

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    A 2‐week‐old female calf was referred to the Clinic for Ruminants at the Vetsuisse Faculty, University of Berne, Switzerland, with difficulty standing and muscle tremors since birth. Prior treatment by the private veterinarian with selenium, calcium, magnesium, and vitamins had not led to any improvement. The general status at arrival to the clinic was slightly reduced, though the calf was alert and attentive, and tachycardia (152/min) and tachypnea (80/min) were noticeable. Examination of the skin revealed an infected lesion on the fetlock of the left forelimb and several superficial lesions. Gastrointestinal, respiratory, and urinary tracts were without important abnormalities. The musculoskeletal system was normally developed, no atrophy was noticed, but the calf remained in a recumbent position unless lifted up and helped to stand. When standing, it showed tremor, ataxia, and could only move backward with hypermetria in the hind limbs and tip‐toe‐standing of the front limbs (Fig 1). Consciousness was normal but the calf was unable to orientate itself in its surroundings. Cranial nerve examination showed no deficits. Muscle tone was generally increased in the limbs. No painful reaction was noticed upon palpation of the limbs. The spinal reflexes were generally reduced. Sensibility was normal in the neck and shoulder area, but reduced in the limbs. The head and neck could be moved in all directions and the ears were symmetrical and loose. The clinical signs were localized in the peripheral nervous or musculoskeletal system

    Kinematic Masses of Super Star Clusters in M82 from High-Resolution Near-Infrared Spectroscopy

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    Using high-resolution (R~22,000) near-infrared (1.51 -- 1.75 microns) spectra from Keck Observatory, we measure the kinematic masses of two super star clusters in M82. Cross-correlation of the spectra with template spectra of cool evolved stars gives stellar velocity dispersions of sigma_r=15.9 +/- 0.8 km/s for MGG-9 and sigma_r=11.4 +/- 0.8 km/s for MGG-11. The cluster spectra are dominated by the light of red supergiants, and correlate most closely with template supergiants of spectral types M0 and M4.5. We fit King models to the observed profiles of the clusters in archival HST/NICMOS images to measure the half-light radii. Applying the virial theorem, we determine masses of 1.5 +/- 0.3 x 10^6 M_sun for MGG-9 and 3.5 +/- 0.7 x 10^5 M_sun for MGG-11. Population synthesis modelling suggests that MGG-9 is consistent with a standard initial mass function, whereas MGG-11 appears to be deficient in low-mass stars relative to a standard IMF. There is, however, evidence of mass segregation in the clusters, in which case the virial mass estimates would represent lower limits.Comment: 16 pages, 8 figures; ApJ, in pres

    RANKL Signaling Sustains Primary Tumor Growth in Genetically Engineered Mouse Models of Lung Adenocarcinoma.

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    NSCLC is the leading cause of cancer mortality. Recent retrospective clinical analyses suggest that blocking the receptor activator of NF-κB (RANK) signaling pathway inhibits the growth of NSCLC and might represent a new treatment strategy. Receptor activator of NF-κB gene (RANK) and receptor activator of NF-κB ligand gene (RANKL) expression in human lung adenocarcinoma was interrogated from publicly available gene expression data sets. Several genetically engineered mouse models were used to evaluate treatment efficacy of RANK-Fc to block RANKL, with primary tumor growth measured longitudinally using microcomputed tomography. A combination of RANKL blockade with cisplatin was tested to mirror an ongoing clinical trial. In human lung adenocarcinoma data sets, RANKL expression was associated with decreased survival and KRAS mutation, with the highest levels in tumors with co-occurring KRAS and liver kinase B1 gene (LKB1) mutations. In Kras <sup>LSL-G12D/WT</sup> , Kras <sup>LSL-G12D/WT</sup> ; Lkb1 <sup>Flox/Flox</sup> and Kras <sup>LSL-G12D/WT</sup> ; p53 <sup>Flox/Flox</sup> mouse models of lung adenocarcinoma, we monitored an impaired progression of tumors upon RANKL blockade. Despite elevated expression of RANKL and RANK in immune cells, treatment response was not associated with major changes in the tumor immune microenvironment. Combined RANK-Fc with cisplatin revealed increased efficacy compared with that of single agents in p53- but not in Lkb1-deficient tumors. RANKL blocking agents impair the growth of primary lung tumors in several mouse models of lung adenocarcinoma and suggest that patients with KRAS-mutant lung tumors will benefit from such treatments

    Detection of ionized gas in the globular cluster 47 Tucanae

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    We report the detection of ionized intracluster gas in the globular cluster 47 Tucanae. Pulsars in this cluster with a negative period derivative, which must lie in the distant half of the cluster, have significantly higher measured integrated electron column densities than the pulsars with a positive period derivative. We derive the plasma density within the central few pc of the cluster using two different methods which yield consistent values. Our best estimate of n_e = (0.067+-0.015)/cm^3 is about 100 times the free electron density of the ISM in the vicinity of 47 Tucanae, and the ionized gas is probably the dominant component of the intracluster medium.Comment: 5 pages, 3 included figures, accepted for publication by ApJ Letter

    Benefit and risk of intrathecal morphine without local anaesthetic in patients undergoing major surgery: meta-analysis of randomized trials

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    Intrathecal morphine without local anaesthetic is often added to a general anaesthetic to prevent pain after major surgery. Quantification of benefit and harm and assessment of dose-response are needed. We performed a meta-analysis of randomized trials testing intrathecal morphine alone (without local anaesthetic) in adults undergoing major surgery under general anaesthesia. Twenty-seven studies (15 cardiac-thoracic, nine abdominal, and three spine surgery) were included; 645 patients received intrathecal morphine (dose-range, 100-4000 µg). Pain intensity at rest was decreased by 2 cm on the 10 cm visual analogue scale up to 4 h after operation and by about 1 cm at 12 and 24 h. Pain intensity on movement was decreased by 2 cm at 12 and 24 h. Opioid requirement was decreased intraoperatively, and up to 48 h after operation. Morphine-sparing at 24 h was significantly greater after abdominal surgery {weighted mean difference, −24.2 mg [95% confidence interval (CI) −29.5 to −19.0]}, compared with cardiac-thoracic surgery [−9.7 mg (95% CI −17.6 to −1.80)]. The incidence of respiratory depression was increased with intrathecal morphine [odds ratio (OR) 7.86 (95% CI 1.54-40.3)], as was the incidence of pruritus [OR 3.85 (95% CI 2.40-6.15)]. There was no evidence of linear dose-responsiveness for any of the beneficial or harmful outcomes. In conclusion, intrathecal morphine decreases pain intensity at rest and on movement up to 24 h after major surgery. Morphine-sparing is more pronounced after abdominal than after cardiac-thoracic surgery. Respiratory depression remains a major safety concer

    PHL 1222: an Interacting Quasar Pair?

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    The "By-Product" of a Survey: The origin of quasars and Active Galactic Nuclei (AGN) is one of the outstanding problems of modern extragalactic astronomy. Mergers and gravitational interactions between galaxies are probably more frequent at large redshifts, and may lead to the appearance of quasars and other AGN. As a matter of fact, there is now an increasing body of evidence - from observations and computer simulations - that gravitational interactions between galaxies may be somehow responsible for the onset and fueling of the nuclear activity (e.g., Hernquist 1989, and references therein)

    On the CR transversality of holomorphic maps into hyperquadrics

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    Let MM_\ell be a smooth Levi-nondegenerate hypersurface of signature \ell in Cn\mathbf C^n with n3 n\ge 3, and write HNH_\ell^N for the standard hyperquadric of the same signature in CN\mathbf C^N with Nn<n12N-n< \frac{n-1}{2}. Let FF be a holomorphic map sending MM_\ell into HNH_\ell^N. Assume FF does not send a neighborhood of MM_\ell in Cn\mathbf C^n into HNH_\ell^N. We show that FF is necessarily CR transversal to MM_\ell at any point. Equivalently, we show that FF is a local CR embedding from MM_\ell into HNH_\ell^N.Comment: To appear in Abel Symposia, dedicated to Professor Yum-Tong Siu on the occasion of his 70th birthda
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