9,404 research outputs found

    Case report: early aortic valve degeneration associated with interstitial deletion of chromosome 2-46,XX,del (2)(q31.3; q32.2).

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    Interstitial deletions within the long arm of chromosome 2, involving the 2q31q33 region, are rare but are known to be associated with delays in development, behavioral problems, facial dysmorphism and various hand/foot anomalies. Here, we describe a case with an interstitial 2q31.3.q32.2 deletion, presenting the previously described phenotype, exhibiting fibromyxoid degeneration of the aortic valve in addition to previously described clinical features. Interstitial deletion in chromosome 2q31.2q32.3 might be associated to a fibromyxoid degeneration of valvular leaflets generating regurgitation. Patients diagnosed with this mutation may require investigation to rule out a valvular disease

    In-orbit Vignetting Calibrations of XMM-Newton Telescopes

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    We describe measurements of the mirror vignetting in the XMM-Newton Observatory made in-orbit, using observations of SNR G21.5-09 and SNR 3C58 with the EPIC imaging cameras. The instrument features that complicate these measurements are briefly described. We show the spatial and energy dependences of measured vignetting, outlining assumptions made in deriving the eventual agreement between simulation and measurement. Alternate methods to confirm these are described, including an assessment of source elongation with off-axis angle, the surface brightness distribution of the diffuse X-ray background, and the consistency of Coma cluster emission at different position angles. A synthesis of these measurements leads to a change in the XMM calibration data base, for the optical axis of two of the three telescopes, by in excess of 1 arcminute. This has a small but measureable effect on the assumed spectral responses of the cameras for on-axis targets.Comment: Accepted by Experimental Astronomy. 26 pages, 18 figure

    Inverse Scattering for Gratings and Wave Guides

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    We consider the problem of unique identification of dielectric coefficients for gratings and sound speeds for wave guides from scattering data. We prove that the "propagating modes" given for all frequencies uniquely determine these coefficients. The gratings may contain conductors as well as dielectrics and the boundaries of the conductors are also determined by the propagating modes.Comment: 12 page

    Global Bounds for the Lyapunov Exponent and the Integrated Density of States of Random Schr\"odinger Operators in One Dimension

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    In this article we prove an upper bound for the Lyapunov exponent γ(E)\gamma(E) and a two-sided bound for the integrated density of states N(E)N(E) at an arbitrary energy E>0E>0 of random Schr\"odinger operators in one dimension. These Schr\"odinger operators are given by potentials of identical shape centered at every lattice site but with non-overlapping supports and with randomly varying coupling constants. Both types of bounds only involve scattering data for the single-site potential. They show in particular that both γ(E)\gamma(E) and N(E)E/πN(E)-\sqrt{E}/\pi decay at infinity at least like 1/E1/\sqrt{E}. As an example we consider the random Kronig-Penney model.Comment: 9 page

    Cardiac Surgery in Advanced Heart Failure.

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    Mechanical circulatory support and heart transplantation are established surgical options for treatment of advanced heart failure. Since the prevalence of advanced heart failure is progressively increasing, there is a clear need to treat more patients with mechanical circulatory support and to increase the number of heart transplantations. This narrative review summarizes recent progress in surgical treatment options of advanced heart failure and proposes an algorithm for treatment of the advanced heart failure patient at >65 years of age

    The First INTEGRAL AGN Catalog

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    We present the first INTEGRAL AGN catalog, based on observations performed from launch of the mission in October 2002 until January 2004. The catalog includes 42 AGN, of which 10 are Seyfert 1, 17 are Seyfert 2, and 9 are intermediate Seyfert 1.5. The fraction of blazars is rather small with 5 detected objects, and only one galaxy cluster and no star-burst galaxies have been detected so far. A complete subset consists of 32 AGN with a significance limit of 7 sigma in the INTEGRAL/ISGRI 20-40 keV data. Although the sample is not flux limited, the distribution of sources shows a ratio of obscured to unobscured AGN of 1.5 - 2.0, consistent with luminosity dependent unified models for AGN. Only four Compton-thick AGN are found in the sample. Based on the INTEGRAL data presented here, the Seyfert 2 spectra are slightly harder (Gamma = 1.95 +- 0.01) than Seyfert 1.5 (Gamma = 2.10 +- 0.02) and Seyfert 1 (Gamma = 2.11 +- 0.05).Comment: 17 pages, 12 figures, accepted for publication in Ap

    Cosmic X-ray background and Earth albedo Spectra with Swift/BAT

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    We use Swift/BAT Earth occultation data at different geomagnetic latitudes to derive a sensitive measurement of the Cosmic X-ray background (CXB) and of the Earth albedo emission in the 15--200 keV band. We compare our CXB spectrum with recent (INTEGRAL, BeppoSAX) and past results (HEAO-1) and find good agreement. Using an independent measurement of the CXB spectrum we are able to confirm our results. This study shows that the BAT CXB spectrum has a normalization ~8(+/-3)% larger than the HEAO-1 measurement. The BAT accurate Earth albedo spectrum can be used to predict the level of photon background for satellites in low Earth and mid inclination orbits.Comment: Accepted for publication in the Astrophysical Journal. 38 Pages, 16 Figures, 2 Table
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