2,279 research outputs found

    Internal Energy of the Potts model on the Triangular Lattice with Two- and Three-body Interactions

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    We calculate the internal energy of the Potts model on the triangular lattice with two- and three-body interactions at the transition point satisfying certain conditions for coupling constants. The method is a duality transformation. Therefore we have to make assumptions on uniqueness of the transition point and that the transition is of second order. These assumptions have been verified to hold by numerical simulations for q=2, 3 and 4, and our results for the internal energy are expected to be exact in these cases.Comment: 9 pages, 4 figure

    Premature ovarian failure in twins: case report

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    Premature ovarian failure (POF)is a serious life-changing condition that affects young women, remains an enigma and the researchers’ challenge. POF, premature ovarian insufficiency (POI), premature menopause, premature dysfunction (POD), or hypergonadotropic hypogonadism is one of the most perplexing disorders with aheterogeneous origin. Infertility, social and psychological stress are common consequences of this entity. This paper presents a rare condition where both twins had presented with POF

    An incidental case of uterus didelphys and fibroids: Right sided myomectomy and left hemi-hysterectomy

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    Congenital anomalies of the uterus occur due to agenesis or lack of fusion of the Mullerian ducts. The incidence of these anomalies is largely  unknown since they are unlikely to be diagnosed in asymptomatic women. Uterine didelphys or double uterus occurs when the two Mullerian ducts  fail to fuse resulting in duplication of the uterus and cervix. This report discusses a case of a 38-yearold woman who had presented with a longstanding history of abnormal uterine bleeding and cyclical pain. She had had two successful vaginal deliveries prior to presentation to our unit. Sonographic findings revealed large uterine myomas and was consented for open myomectomy. Intraoperatively she was found to have two uteri, both of which had intramural fibroids and two cervices. Keywords: didelphys uterus, fibroid

    Helium, Oxygen, Proton, and Electron (HOPE) Mass Spectrometer for the Radiation Belt Storm Probes Mission

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    The HOPE mass spectrometer of the Radiation Belt Storm Probes (RBSP) mission (renamed the Van Allen Probes) is designed to measure the in situ plasma ion and electron fluxes over 4π sr at each RBSP spacecraft within the terrestrial radiation belts. The scientific goal is to understand the underlying physical processes that govern the radiation belt structure and dynamics. Spectral measurements for both ions and electrons are acquired over 1 eV to 50 keV in 36 log-spaced steps at an energy resolution ΔE FWHM/E≈15 %. The dominant ion species (H+, He+, and O+) of the magnetosphere are identified using foil-based time-of-flight (TOF) mass spectrometry with channel electron multiplier (CEM) detectors. Angular measurements are derived using five polar pixels coplanar with the spacecraft spin axis, and up to 16 azimuthal bins are acquired for each polar pixel over time as the spacecraft spins. Ion and electron measurements are acquired on alternate spacecraft spins. HOPE incorporates several new methods to minimize and monitor the background induced by penetrating particles in the harsh environment of the radiation belts. The absolute efficiencies of detection are continuously monitored, enabling precise, quantitative measurements of electron and ion fluxes and ion species abundances throughout the mission. We describe the engineering approaches for plasma measurements in the radiation belts and present summaries of HOPE measurement strategy and performance

    Transmission of Information in Active Networks

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    Shannon's Capacity Theorem is the main concept behind the Theory of Communication. It says that if the amount of information contained in a signal is smaller than the channel capacity of a physical media of communication, it can be transmitted with arbitrarily small probability of error. This theorem is usually applicable to ideal channels of communication in which the information to be transmitted does not alter the passive characteristics of the channel that basically tries to reproduce the source of information. For an {\it active channel}, a network formed by elements that are dynamical systems (such as neurons, chaotic or periodic oscillators), it is unclear if such theorem is applicable, once an active channel can adapt to the input of a signal, altering its capacity. To shed light into this matter, we show, among other results, how to calculate the information capacity of an active channel of communication. Then, we show that the {\it channel capacity} depends on whether the active channel is self-excitable or not and that, contrary to a current belief, desynchronization can provide an environment in which large amounts of information can be transmitted in a channel that is self-excitable. An interesting case of a self-excitable active channel is a network of electrically connected Hindmarsh-Rose chaotic neurons.Comment: 15 pages, 5 figures. submitted for publication. to appear in Phys. Rev.

    Bicornuate unicollis uterine Müllerian anomaly with unilateral haematometra in a ten year old: A case report

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    Acute abdominal pain is a common complaint in the paediatric age group. Gastroenteritis and appendicitis are the common non-surgical and surgical conditions respectively. Haematometra due to a non-communicating horn of a bicornuate uterus is a rare presentation for acute abdomen in this age group. This is a case of a ten year nine month old female who presented with an acute abdomen for a period of two days. Physical examination revealed right iliac fossa tenderness. Pelvic ultrasound showed a bicornuate unicollis uterine Müllerian anomaly with unilateral haematometra. Magnetic Resonance Imaging (MRI) confirmed the ultrasonographic findings. A successful hemi-hysterectomy was done with resolution of symptoms

    A practical guide for collecting farmers socio-economic and agronomic data: an AfSIS Project field protocol

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    One of the aims of the AfSIS (Africa Soil Information Service) project is to document farmers’ characteristics and practices to determine their ability to engage in effective soil and crop management. This document outlines how agronomic surveys are integrated with knowledge of farmers’ condition, wealth, status, access to knowledge, and access to markets, using pre-designed questionnaires and field surveys, and including the use of Global Positioning System-based field surveys and Geographic Information Systems

    Probing a non-biaxial behavior of infinitely thin hard platelets

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    We give a criterion to test a non-biaxial behavior of infinitely thin hard platelets of D2hD_{2h} symmetry based upon the components of three order parameter tensors. We investigated the nematic behavior of monodisperse infinitely thin rectangular hard platelet systems by using the criterion. Starting with a square platelet system, and we compared it with rectangular platelet systems of various aspect ratios. For each system, we performed equilibration runs by using isobaric Monte Carlo simulations. Each system did not show a biaxial nematic behavior but a uniaxial nematic one, despite of the shape anisotropy of those platelets. The relationship between effective diameters by simulations and theoretical effective diameters of the above systems was also determined.Comment: Submitted to JPS

    Magnetic and Dielectric Properties in Multiferroic Cu3Mo2O9 under High Magnetic Fields

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    The magnetic and dielectric properties under high magnetic fields are studied in the single crystal of Cu3Mo2O9. This multiferroic compound has distorted tetrahedral spin chains. The effects of the quasi-one dimensionality and the geometrical spin frustration are expected to appear simultaneously. We measure the magnetoelectric current and the differential magnetization under the pulsed magnetic field up to 74 T. We also measure the electric polarization versus the electric field curve/loop under the static field up to 23 T. Dielectric properties change at the magnetic fields where the magnetization jumps are observed in the magnetization curve. Moreover, the magnetization plateaus are found at high magnetic fields.Comment: 6 pages, 3 figures, in press in JPS Conf. Proc. as a part of SCES2013 Proceeding

    Three-dimensional antiferromagnetic q-state Potts models: application of the Wang-Landau algorithm

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    We apply a newly proposed Monte Carlo method, the Wang-Landau algorithm, to the study of the three-dimensional antiferromagnetic q-state Potts models on a simple cubic lattice. We systematically study the phase transition of the models with q=3, 4, 5 and 6. We obtain the finite-temperature phase transition for q= 3 and 4, whereas the transition temperature is down to zero for q=5. For q=6 there exists no order for all the temperatures. We also study the ground-state properties. The size-dependence of the ground-state entropy is investigated. We find that the ground-state entropy is larger than the contribution from the typical configurations of the broken-sublattice-symmetry state for q=3. The same situations are found for q = 4, 5 and 6.Comment: 9 pages including 9 eps figures, RevTeX, to appear in J. Phys.
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