7,340 research outputs found

    Asymmetric double-well potential for single atom interferometry

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    We consider the evolution of a single-atom wavefunction in a time-dependent double-well interferometer in the presence of a spatially asymmetric potential. We examine a case where a single trapping potential is split into an asymmetric double well and then recombined again. The interferometer involves a measurement of the first excited state population as a sensitive measure of the asymmetric potential. Based on a two-mode approximation a Bloch vector model provides a simple and satisfactory description of the dynamical evolution. We discuss the roles of adiabaticity and asymmetry in the double-well interferometer. The Bloch model allows us to account for the effects of asymmetry on the excited state population throughout the interferometric process and to choose the appropriate splitting, holding and recombination periods in order to maximize the output signal. We also compare the outcomes of the Bloch vector model with the results of numerical simulations of the multi-state time-dependent Schroedinger equation.Comment: 9 pages, 6 figure

    Transient Myocarditis Associated with Fulminant Colitis

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    Case Summary. An 18-year old man presented with a three-week history of abdominal pain, weight loss and bloody diarrhoea. He was profoundly septic, with generalised abdominal tenderness. CT and flexible sigmoidosopy confirmed colitis of the colon with rectal sparing. Laparotomy was performed when conservative management failed to improve his condition. Subtotal colectomy, with end ileostomy and mucus fistula formation, was performed in light of active colitis. Despite successful operative intervention the patient acute left ventricular failure, raising the possibility of giant cell myocarditis, which fully resolved before a definitive diagnosis could be reached. Discussion. It is possible that the transient cardiac failure in this case may represent an overwhelming inflammatory response or myocarditis. Inflammatory bowel disease is rarely associated with giant cell myocarditis (GCM). GCM usually affects a young population and its prognosis is variable, ranging from complete recovery, remission with recurrence and fatality. The management of this group of patients is still relatively experimental. Conclusion. Fulminant colitis can be associated with a rapid deterioration in cardiac function. Causes include sepsis, systemic inflammatory response syndrome or myocarditis. GCM should be considered in patients with new onset of left ventricular failure that decline rapidly

    Controlled coupling of counterpropagating whispering-gallery modes by a single Rayleigh scatterer: a classical problem in a quantum optical light

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    We present experiments where a single subwavelength scatterer is used to examine and control the back-scattering induced coupling between counterpropagating high-Q modes of a microsphere resonator. Our measurements reveal the standing wave character of the resulting symmetric and antisymmetric eigenmodes, their unbalanced intensity distributions, and the coherent nature of their coupling. We discuss our findings and the underlying classical physics in the framework common to quantum optics and provide a particularly intuitive explanation of the central processes.Comment: accepted for publication in Pysical Review Letter

    On Real Fluid Flow Over Yawed Circular Cylinders

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    The equations for both the boundary layer and the outer potential flow over a yawed cylinder can be resolved into equations for the crosswise and spanwise velocity components. These components of the boundary layer are evaluated using Sears’ method, and the separation point is found to be uninfluenced by the yaw angle. The potential-flow solutions for the spanwise and crosswise flows are added together to determine vortex patterns behind the cylinder. The approximate direct dependence of the Strouhal number upon the cosine of the yaw angle and/or the drag coefficient upon the square of the cosine, are verified. Experimental determinations of the Strouhal number and visualization of the flow pattern are consistent with the analysis

    The radical left's turn towards civil society in Greece: One strategy, two paths

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    The Communist Party of Greece (KKE) and the Coalition of the Radical Left (SYRIZA) made remarkable ‘turns towards civil society’ over the last decade. It is argued that this was primarily a response aimed at strengthening their social legitimacy, which had reached its lowest point in the early 1990s. Differences in the way the two parties attempted to stabilise and engage their membership and re-establish links to trade unions and new social movements can be attributed to their distinct ideological and organisational legacies. Despite those differences, their respective linkage strategies were both successful until the game-changing 2012 Greek national elections, which brought about the remarkable rise of SYRIZA and the electoral demise of the KKE

    The Aquarius Superclusters - I. Identification of Clusters and Superclusters

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    We study the distribution of galaxies and galaxy clusters in a 10^deg x 6^deg field in the Aquarius region. In addition to 63 clusters in the literature, we have found 39 new candidate clusters using a matched-filter technique and a counts-in-cells analysis. From redshift measurements of galaxies in the direction of these cluster candidates, we present new mean redshifts for 31 previously unobserved clusters, while improved mean redshifts are presented for 35 other systems. About 45% of the projected density enhancements are due to the superposition of clusters and/or groups of galaxies along the line of sight, but we could confirm for 72% of the cases that the candidates are real physical associations similar to the ones classified as rich galaxy clusters. On the other hand, the contamination due to galaxies not belonging to any concentration or located only in small groups along the line of sight is ~ 10%. Using a percolation radius of 10 h^{-1} Mpc (spatial density contrast of about 10), we detect two superclusters of galaxies in Aquarius, at z = 0.086 and at z = 0.112, respectively with 5 and 14 clusters. The latter supercluster may represent a space overdensity of about 160 times the average cluster density as measured from the Abell et al. (1989) cluster catalog, and is possibly connected to a 40 h^{-1} Mpc filament from z ~ 0.11 to 0.14.Comment: LateX text (21 pages) and 12 (ps/eps/gif) figures; figures 5a, 5b and 6 are not included in the main LateX text; to be published in the Astronomical Journal, March issu

    Belmont Criminal Law Journal Symposium 2017: Judicial Panel

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    Transcript of the Judicial Panel given during the 2017 Symposium featuring Chief Justice Jeffrey S. Bivins, Judge Joseph A. Woodruff, Judge Timothy L. Easter, and Judge Angelita B. Dalton

    The E-ELT Multi-Object Spectrograph: latest news from MOSAIC

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    There are 8000 galaxies, including 1600 at z larger than 1.6, which could be simultaneously observed in an E-ELT field of view of 40 sq. arcmin. A considerable fraction of astrophysical discoveries require large statistical samples, which can only be obtained with multi-object spectrographs (MOS). MOSAIC will provide a vast discovery space, enabled by a multiplex of 200 and spectral resolving powers of R=5000 and 20000. MOSAIC will also offer the unique capability of more than 10 "high-definition" (multi-object adaptive optics, MOAO) integral-field units, optimised to investigate the physics of the sources of reionization. The combination of these modes will make MOSAIC the world-leading MOS facility, contributing to all fields of contemporary astronomy, from extra-solar planets, to the study of the halo of the Milky Way and its satellites, and from resolved stellar populations in nearby galaxies out to observations of the earliest "first-light" structures in the Universe. It will also study the distribution of the dark and ordinary matter at all scales and epochs of the Universe. Recent studies of critical technical issues such as sky-background subtraction and MOAO have demonstrated that such a MOS is feasible with state-of-the-art technology and techniques. Current studies of the MOSAIC team include further trade-offs on the wavelength coverage, a solution for compensating for the non-telecentric new design of the telescope, and tests of the saturation of skylines especially in the near-IR bands. In the 2020s the E-ELT will become the world's largest optical/IR telescope, and we argue that it has to be equipped as soon as possible with a MOS to provide the most efficient, and likely the best way to follow-up on James Webb Space Telescope (JWST) observations.Comment: 10 pages, 3 Figures, in Ground-based and Airborne Instrumentation for Astronomy VI, 2016, Proc. SPI
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