866 research outputs found

    The Voyage of the "Snowbird II"

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    Account of the trip of the converted U.S. Navy landing ship medium, Snowbird II, from Vancouver, B.C. to Cambridge Bay, Victoria Island, 1948, to supply the Royal Canadian Mounted Police post there. Describes special features of the ship, and her movements in the ice of Beaufort Sea and Canadian straits, aided by air reconnaissance

    Vortex ordering in fully-frustrated superconducting systems with dice lattice

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    The structure and the degenracy of the ground state of a fully-frustrated XY-model are investigated for the case of a dice lattice geometry. The results are applicable for the description of Josephson junction arrays and thin superconducting wire networks in the external magnetic field providing half-integer number of flux quanta per plaquette. The mechanisms of disordering of vortex pattern in such systems are briefly discussed.Comment: 10 pages, 3 figure

    Infectious diseases co-morbidities among patients attending Kogi State University Teaching Hospital: a ten-year retrospective study

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    Background: Co-existence of more than one acute or chronic infectious diseases in a person either concurrently or sequentially with consequent economic burden varies differently from one part of the world to another, with regional and population specific patterns. This study aims to provide co-morbid patho-epidemiological pattern of six infectious diseases; HIV, tuberculosis (TB), malaria, syphilis, hepatitis B and hepatitis C virus infections. Methodology: This research is a ten-year retrospective review of records of patients admitted at various wards of Kogi State University Teaching hospital and referred to the Laboratory Department of the hospital for investigations between June 2012 and July 2021. HIV was screened using the national serial algorithm, TB was diagnosed with the GeneXpert MTB, malaria parasite was identified by blood film microscopy, and syphilis, hepatitis B and hepatitis C viruses were screened using rapid diagnostic kits. Data were analysed with SPSS version 23.0 and association of variables with respect to gender and age group was determined using Chi square, with p< 0.05 considered to be statistically significant. Results: A total of 223 patients were retrospectively reviewed with 102 (45.7%) males and 121 (54.3%) females. Co-morbidities occurred most frequently among age groups 21-30 years (34.1%), 31-40 years (39.0%) and 41-50 years (16.6%). The most frequent co-morbidity pattern was HIV/TB (81.6%) followed by HBV/MP (4.5%), HIV/HBV (4.0%), HIV/MP (3.1%), TB/MP (2.7%), HBV/HCV (2.2%) while HCV/MP, TB/HCV, HCV/syphilis, and TB/HBV were (0.4%) each. There was no significant difference in the frequency of co-morbidity with respect to gender and age groups of patients (p>0.05). Conclusion: Co-existence of chronic infectious disease in a person increases the risk of morbidities and mortalities. Therefore, diagnosis, and concurrent treatment and management of co-morbid infectious diseases should be incorporated into our routine healthcare system and appropriate resources should be allotted for this in health plans.   Frebch title: Co-morbidités des maladies infectieuses chez les patients fréquentant l'hôpital universitaire de l'État de Kogi: une étude rétrospective sur dix ans Contexte: La coexistence de plusieurs maladies infectieuses aiguës ou chroniques chez une personne, simultanément ou séquentiellement, avec un fardeau économique conséquent, varie différemment d'une partie du monde à l'autre, avec des schémas régionaux et spécifiques à la population. Cette étude vise à fournir le schéma patho-épidémiologique comorbide de six maladies infectieuses; VIH, tuberculose (TB), paludisme, syphilis, infections par le virus de l'hépatite B et de l'hépatite C. Méthodologie: Cette recherche est un examen rétrospectif sur dix ans des dossiers de patients admis dans divers services de l'hôpital universitaire de l'État de Kogi et référés au département de laboratoire de l'hôpital pour des enquêtes entre juin 2012 et juillet 2021. Le VIH a été dépisté à l'aide de la série nationale algorithme, la tuberculose a été diagnostiquée avec le GeneXpert MTB, le parasite du paludisme a été identifié par microscopie de frottis sanguin et les virus de la syphilis, de l'hépatite B et de l'hépatite C ont été dépistés à l'aide de kits de diagnostic rapide. Les données ont été analysées avec SPSS version 23.0 et l'association des variables par rapport au sexe et au groupe d'âge a été déterminée à l'aide du Chi carré, avec p<0,05 considéré comme statistiquement significatif. Résultats: Un total de 223 patients ont été revus rétrospectivement avec 102 (45,7%) hommes et 121 (54,3%) femmes. Les comorbidités sont survenues le plus fréquemment dans les groupes d'âge 21-30 ans (34,1 %), 31-40 ans (39,0%) et 41-50 ans (16,6%). Le schéma de comorbidité le plus fréquent était le VIH/TB (81,6%), suivi du VHB/MP (4,5%), du VIH/VHB (4,0%), du VIH/MP (3,1%), de la TB/MP (2,7%), du VHB/VHC (2,2%) tandis que VHC/MP, TB/VHC, VHC/syphilis et TB/VHB étaient (0,4%) chacun. Il n'y avait pas de différence significative dans la fréquence des comorbidités en fonction du sexe et des tranches d'âge des patients (p>0,05). Conclusion: La coexistence de maladies infectieuses chroniques chez une personne augmente le risque de morbidité et de mortalité. Par conséquent, le diagnostic, le traitement et la gestion concomitants des maladies infectieuses comorbides doivent être intégrés à notre système de soins de santé de routine et des ressources appropriées doivent être allouées à cet effet dans les plans de santé

    Quantum optical coherence tomography with dispersion cancellation

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    We propose a new technique, called quantum optical coherence tomography (QOCT), for carrying out tomographic measurements with dispersion-cancelled resolution. The technique can also be used to extract the frequency-dependent refractive index of the medium. QOCT makes use of a two-photon interferometer in which a swept delay permits a coincidence interferogram to be traced. The technique bears a resemblance to classical optical coherence tomography (OCT). However, it makes use of a nonclassical entangled twin-photon light source that permits measurements to be made at depths greater than those accessible via OCT, which suffers from the deleterious effects of sample dispersion. Aside from the dispersion cancellation, QOCT offers higher sensitivity than OCT as well as an enhancement of resolution by a factor of 2 for the same source bandwidth. QOCT and OCT are compared using an idealized sample.Comment: 19 pages, 4 figure

    The second and third Sonine coefficients of a freely cooling granular gas revisited

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    In its simplest statistical-mechanical description, a granular fluid can be modeled as composed of smooth inelastic hard spheres (with a constant coefficient of normal restitution α\alpha) whose velocity distribution function obeys the Enskog-Boltzmann equation. The basic state of a granular fluid is the homogeneous cooling state, characterized by a homogeneous, isotropic, and stationary distribution of scaled velocities, F(c)F(\mathbf{c}). The behavior of F(c)F(\mathbf{c}) in the domain of thermal velocities (c1c\sim 1) can be characterized by the two first non-trivial coefficients (a2a_2 and a3a_3) of an expansion in Sonine polynomials. The main goals of this paper are to review some of the previous efforts made to estimate (and measure in computer simulations) the α\alpha-dependence of a2a_2 and a3a_3, to report new computer simulations results of a2a_2 and a3a_3 for two-dimensional systems, and to investigate the possibility of proposing theoretical estimates of a2a_2 and a3a_3 with an optimal compromise between simplicity and accuracy.Comment: 12 pages, 5 figures; v2: minor change

    High Energy QCD: Stringy Picture from Hidden Integrability

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    We discuss the stringy properties of high-energy QCD using its hidden integrability in the Regge limit and on the light-cone. It is shown that multi-colour QCD in the Regge limit belongs to the same universality class as superconformal N\cal{N}=2 SUSY YM with Nf=2NcN_f=2N_c at the strong coupling orbifold point. The analogy with integrable structure governing the low energy sector of N\cal{N}=2 SUSY gauge theories is used to develop the brane picture for the Regge limit. In this picture the scattering process is described by a single M2 brane wrapped around the spectral curve of the integrable spin chain and unifying hadrons and reggeized gluons involved in the process. New quasiclassical quantization conditions for the complex higher integrals of motion are suggested which are consistent with the SS-duality of the multi-reggeon spectrum. The derivation of the anomalous dimensions of the lowest twist operators is formulated in terms of the Riemann surfacesComment: 37 pages, 3 figure

    Baxter Q-operator and Separation of Variables for the open SL(2,R) spin chain

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    We construct the Baxter Q-operator and the representation of the Separated Variables (SoV) for the homogeneous open SL(2,R) spin chain. Applying the diagrammatical approach, we calculate Sklyanin's integration measure in the separated variables and obtain the solution to the spectral problem for the model in terms of the eigenvalues of the Q-operator. We show that the transition kernel to the SoV representation is factorized into the product of certain operators each depending on a single separated variable. As a consequence, it has a universal pyramid-like form that has been already observed for various quantum integrable models such as periodic Toda chain, closed SL(2,R) and SL(2,C) spin chains.Comment: 29 pages, 9 figures, Latex styl

    Estimating the parameters of the Sgr A* black hole

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    The measurement of relativistic effects around the galactic center may allow in the near future to strongly constrain the parameters of the supermassive black hole likely present at the galactic center (Sgr A*). As a by-product of these measurements it would be possible to severely constrain, in addition, also the parameters of the mass-density distributions of both the innermost star cluster and the dark matter clump around the galactic center.Comment: Accepted for publication on General Relativity and Gravitation, 2010. 11 Pages, 1 Figur

    Multi-parameter Entanglement in Quantum Interferometry

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    The role of multi-parameter entanglement in quantum interference from collinear type-II spontaneous parametric down-conversion is explored using a variety of aperture shapes and sizes, in regimes of both ultrafast and continuous-wave pumping. We have developed and experimentally verified a theory of down-conversion which considers a quantum state that can be concurrently entangled in frequency, wavevector, and polarization. In particular, we demonstrate deviations from the familiar triangular interference dip, such as asymmetry and peaking. These findings improve our capacity to control the quantum state produced by spontaneous parametric down-conversion, and should prove useful to those pursuing the many proposed applications of down-converted light.Comment: submitted to Physical Review
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