1,881 research outputs found

    Two Cases of Primary Ectopic Ovarian Pregnancy

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    Primary ovarian pregnancy is one of the rarest varieties of ectopic pregnancies. Patients frequently present with abdominal pain and menstrual irregularities. Intrauterine devices have evolved as probable risk factors. Preoperative diagnosis is challenging but transvaginal sonography has often been helpful. A diagnostic delay may lead to rupture, secondary implantation or operative difficulties. Therefore, awareness of this rare condition is important in reducing the associated risks. Here, we report two cases of primary ovarian pregnancies presenting with acute abdominal pain. Transabdominal ultrasonography failed to hint at ovarian pregnancy in one, while transvaginal sonography aided in the correct diagnosis of the other. Both cases were confirmed by histopathological examinations and were successfully managed by surgery

    Effect of Salt Concentration on the Electrophoretic Speed of a Polyelectrolyte through a Nanopore

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    In a previous paper [S. Ghosal, Phys. Rev. E 74, 041901 (2006)] a hydrodynamic model for determining the electrophoretic speed of a polyelectrolyte through an axially symmetric slowly varying nanopore was presented in the limit of a vanishingly small Debye length. Here the case of a finite Debye layer thickness is considered while restricting the pore geometry to that of a cylinder of length much larger than the diameter. Further, the possibility of a uniform surface charge on the walls of the nanopore is taken into account. It is thereby shown that the calculated transit times are consistent with recent measurements in silicon nanopores.Comment: 4 pages, 2 figure

    Local Identification of Subsets of Quantum states: A Stronger Quantum Nonlocality

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    Nonolocality makes quantum theory nontrivially sacred and useful in the paradigm of information theoretic tasks. Apart from Bell nonlocality, which deals with measurement outcome statistics of spatially separated agents, there is also another kind of quantum nonlocality, that is associated with perfect distinguishability of quantum states by local operations and classical communication (LOCC). We propose a distributed task: perfect identification of subsets of a known set of multipartite orthogonal states by LOCC, namely, local subset identification. Failure in accomplishing this task guarantees a new notion of quantum nonlocality, viz., local subset unidentifiability. Here, we show that both local distinguishability and local markability of quantum states implies local subset identifiability, but the converse is not necessarily true. This makes local subset unidentifiability a stronger quantum nonlocal phenomenon than its predecessors -- local indistinguishability and local unmarkability. Moreover, we also present an even stronger version of local subset unidentifiablity involving more than two spatially separated parties namely, genuine local subset unidentifiability, where a given subset becomes identifiable if and only if all the parties come together in a common lab.Comment: Initial draft, New results added, Comments are welcom

    Robustness of d-Density Wave Order to Nonmagnetic Impurities

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    Effect of finite density of nonmagnetic impurities on a coexisting phase of d-density wave (DDW) order and d-wave superconducting (DSC) order is studied using Bogoliubov-de Gennes (BdG) method. The spatial variation of the inhomogeneous DDW order due to impurities has a strong correlation with that of density, which is very different from that of DSC order. The length scale associated with DDW is found to be of the order of a lattice spacing. The nontrivial inhomogeneities are shown to make DDW order much more robust to the impurities, while DSC order becomes very sensitive to them. The effect of disorder on the density of states is also discussed.Comment: 4 pages, 3 PostScript figure

    Rotation periods and colours of 10-m scale near-Earth asteroids from CFHT target of opportunity streak photometry

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    The rotational properties of \sim10~m-scale asteroids are poorly understood with only a few measurements. Additionally, collisions or thermal recoil can spin their rotations to periods less than a few seconds obfuscating their study due to the observational cadence imposed by the long read-out times of charge-coupled device imagers. We present a method to measure the rotation periods of 10~m-scale asteroids using the target of opportunity capability of the Canada France Hawaii Telescope and its MegaCam imager by intentionally streaking their detections in single exposures when they are at their brightest. Periodic changes in brightness as small as \sim0.05 mag along the streak can be measured as short as a few seconds. Additionally, the streak photometry is taken in multiple g, r, and i filter exposures enabling the measurement of asteroid colours. The streak photometry method was tested on CFHT observations of three 10~m-scale asteroids, 2016 GE1_1, 2016 CG18_{18}, and 2016 EV84_{84}. Our 3 targets are among the smallest known asteroids with measured rotation periods/colours having some of the shortest known rotation periods. We compare our rotation period and taxonomic results with independent data from the literature and discuss applications of the method to future small asteroid observations.Comment: Revised version, MNRAS:L, 13 pages, 10 figures, 3 table

    Reactive chemical dynamics through conical intersections

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    Reaction dynamics of prototypical, D + H2 and Cl (2P) + H2, chemical reactions occurring through the conical intersections of the respective coupled multi-sheeted potential energy surfaces is examined here. In addition to the electronic coupling, nonadiabatic effects due to relativistic spin-orbit coupling are also considered for the latter reaction. A time-dependent wave packet propagation approach is undertaken and the quantum dynamical observables viz., energy resolved reaction probabilities, integral reaction cross-sections and thermal rate constants are reported

    A GEANT-based study of atmospheric neutrino oscillation parameters at INO

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    We have studied the dependence of the allowed space of the atmospheric neutrino oscillation parameters on the time of exposure for a magnetized Iron CALorimeter (ICAL) detector at the India-based Neutrino Observatory (INO). We have performed a Monte Carlo simulation for a 50 kTon ICAL detector generating events by the neutrino generator NUANCE and simulating the detector response by GEANT. A chi-square analysis for the ratio of the up-going and down-going neutrinos as a function of L/EL/E is performed and the allowed regions at 90% and 99% CL are displayed. These results are found to be better than the current experimental results of MINOS and Super-K. The possibilities of further improvement have also been discussed.Comment: 8 pages, 13 figures, a new figure added, version accepted in IJMP

    Single-Particle Density of States of a Superconductor with a Spatially Varying Gap and Phase Fluctuations

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    Recent experiments have shown that the superconducting energy gap in some cuprates is spatially inhomogeneous. Motivated by these experiments, and using exact diagonalization of a model d-wave Hamiltonian, combined with Monte Carlo simulations of a Ginzburg-Landau free energy functional, we have calculated the single-particle density of states LDOS(ω,r)(\omega,r) of a model high-Tc_c superconductor as a function of temperature. Our calculations include both quenched disorder in the pairing potential and thermal fluctuations in both phase and amplitude of the superconducting gap. Most of our calculations assume two types of superconducting regions: α\alpha, with a small gap and large superfluid density, and β\beta, with the opposite. If the β\beta regions are randomly embedded in an α\alpha host, the LDOS on the α\alpha sites still has a sharp coherence peak at T=0T = 0, but the β\beta component does not, in agreement with experiment. An ordered arrangement of β\beta regions leads to oscillations in the LDOS as a function of energy. The model leads to a superconducting transition temperature TcT_c well below the pseudogap temperature Tc0T_{c0}, and has a spatially varying gap at very low TT, both consistent with experiments in underdoped Bi2212. Our calculated LDOS(ω,r)(\omega,r) shows coherence peaks for TTcT T_c, in agreement with previous work considering phase but not amplitude fluctuations in a homogeneous superconductor. Well above TcT_c, the gap in the LDOS disappears.Comment: 37 pages, 12 figures. Accepted by Phys. Rev. B. Scheduled Issue: 01 Nov 200

    Effect of carbon nanofibre addition on the mechanical properties of different Vf carbon-epoxy composites

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    Carbon-epoxy (C-epoxy) laminated composites having different fibre volume fractions (40, 50, 60 and 70) were fabricated with and without the addition of aminofunctionalized carbon nanofibres (A-CNF). Flexural strength, interlaminar shear strength (ILSS) and tensile strength of the composite laminates were determined. It was observed that, the ability of A-CNF to enhance the mechanical properties of C-epoxy diminished significantly as the fibre volume fraction (Vf) of the C-epoxy increased from 40 to 60. At 70Vf, the mechanical properties of the ACNF reinforced C-epoxy were found to be lower compared to the C-epoxy composite made without the addition of A-CNF. In this paper suitable mechanisms for the observed trends are proposed on the basis of the fracture modes of the composite
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