603 research outputs found

    Subdirect Sum of Ternary Rings and Subdirectly Irreducible Ternary Rings

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    In this paper we introduce the notions of subdirect sum of a family of ternary rings and the representation of a ternary ring as a subdirect sum of a family of ternary rings. We also introduce the notion of subdirectly irreducible ternary ring and characterize it. Lastly we characterize subdirectly irreducible Boolean ternary rings

    Supernova neutrino oscillations: A simple analytical approach

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    Analyses of observable supernova neutrino oscillation effects require the calculation of the electron (anti)neutrino survival probability P_ee along a given supernova matter density profile. We propose a simple analytical prescription for P_ee, based on a double-exponential form for the crossing probability and on the concept of maximum violation of adiabaticity. In the case of two-flavor transitions, the prescription is shown to reproduce accurately, in the whole neutrino oscillation parameter space, the results of exact numerical calculations for generic (realistic or power-law) profiles. The analytical approach is then generalized to cover three-flavor transitions with (direct or inverse) mass spectrum hierarchy, and to incorporate Earth matter effects. Compact analytical expressions, explicitly showing the symmetry properties of P_ee, are provided for practical calculations.Comment: 22 pages (RevTeX) + 5 figures (PostScript

    Supersymmetric isospectral formalism for the calculation of near-zero energy states: application to the very weakly bound 4{^4}He trimer excited state

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    We propose a novel mathematical approach for the calculation of near-zero energy states by solving potentials which are isospectral with the original one. For any potential, families of strictly isospectral potentials (with very different shape) having desirable and adjustable features are generated by supersymmetric isospectral formalism. The near-zero energy Efimov state in the original potential is effectively trapped in the deep well of the isospectral family and facilitates more accurate calculation of the Efimov state. Application to the first excited state in 4He trimer is presented.Comment: accepte

    Implications of recent solar neutrino observations: an analysis of charged current data

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    We have analysed the recent results from the observation of charged current \nu_e d \to e^- p p events from solar neutrinos by the Sudbury Neutrino Observatory SNO assuming neutrino oscillations with three active flavours. The data seem to prefer a low mass-squared difference and large mixing angle solution (the so-called LOW solution) in (12) parameter space. However, when combined with the Gallium charged current interaction data from Gallex and GNO, distinct (1\sigma) allowed regions corresponding to the large mixing angle (LMA) and small mixing angle (SMA) appear while the LOW solution is disfavoured upto 3\sigma standard deviation. The physical electron neutrino survival probability corresponding to these best fit solutions are then determined and analysed for their energy dependence.Comment: 16 pages Latex file, with 5 epsf figures; one reference adde

    STUDIES ON INCIDENCE AND ANTIBIOGRAM OF SALMONELLA SEROVARS ISOLATED FROM RAW PORK IN AIZAWL AND IMPHAL, INDIA

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    The study was conducted to determine the incidence, serotypes and antimicrobial resistance profile of Salmonella serovars isolated from raw pork of Aizawl and Imphal, India. A total of 200 raw pork samples (100 from Aizawl and Imphal each) were collected from unorganized butcher shops and subjected for isolation and identification of Salmonella spp. which phenotypically detected 5 Salmonella isolates. The Salmonella isolates were further confirmed genotypically by 16S rRNA genus specific PCR and recorded the incidence rate of 2.50%. Serotyping of the isolates revealed that all the three isolates from Imphal were Salmonella enterica serovar Virchow whereas the two isolates of Aizawl were Salmonella enterica serovar Virchow and Salmonella enterica serovar Typhimurium, one each. The antimicrobial sensitivity profile against 16 antimicrobials revealed that amikacin, imipenem, ofloxacine, norfloxacin and ciprofloxacin were 100% sensitive and among the resistant antimicrobials, highest resistance was recorded against ceftriaxone (80.00%) followed by amoxyclav and cotrimoxazole (60.00% each). Presence of Salmonella Typhimurium from raw pork is a matter of concern from hygiene and sanitation. Moreover, the antimicrobial resistance profile showed increasing resistance against cephalosporin, amino-penicillin and amino glycosides

    Probing Kaluza-Klein Dark Matter with Neutrino Telescopes

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    In models in which all of the Standard Model fields live in extra universal dimensions, the lightest Kaluza-Klein (KK) particle can be stable. Calculations of the one-loop radiative corrections to the masses of the KK modes suggest that the identity of the lightest KK particle (LKP) is mostly the first KK excitation of the hypercharge gauge boson. This LKP is a viable dark matter candidate with an ideal present-day relic abundance if its mass is moderately large, between 600 to 1200 GeV. Such weakly interacting dark matter particles are expected to become gravitationally trapped in large bodies, such as the Sun, and annihilate into neutrinos or other particles that decay into neutrinos. We calculate the annihilation rate, neutrino flux and the resulting event rate in present and future neutrino telescopes. The relatively large mass implies that the neutrino energy spectrum is expected to be well above the energy threshold of AMANDA and IceCube. We find that the event rate in IceCube is between a few to tens of events per year.Comment: 13 pages, 3 figures, LaTeX; typos fixed, version to appear in PR

    Search for DCC in 158A GeV Pb+Pb Collisions

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    A detailed analysis of the phase space distributions of charged particles and photons have been carried out using two independent methods. The results indicate the presence of nonstatistical fluctuations in localized regions of phase space.Comment: Talk at the PANIC99 Conference, June 9-16, 199

    Pion Freeze-Out Time in Pb+Pb Collisions at 158 A GeV/c Studied via pi-/pi+ and K-/K+ Ratios

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    The effect of the final state Coulomb interaction on particles produced in Pb+Pb collisions at 158 A GeV/c has been investigated in the WA98 experiment through the study of the pi-/pi+ and K-/K+ ratios measured as a function of transverse mass. While the ratio for kaons shows no significant transverse mass dependence, the pi-/pi+ ratio is enhanced at small transverse mass values with an enhancement that increases with centrality. A silicon pad detector located near the target is used to estimate the contribution of hyperon decays to the pi-/pi+ ratio. The comparison of results with predictions of the RQMD model in which the Coulomb interaction has been incorporated allows to place constraints on the time of the pion freeze-out.Comment: 9 pages, 12 figure

    Present Status and Future of DCC Analysis

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    Disoriented Chiral Condensates (DCC) have been predicted to form in high energy heavy ion collisions where the approximate chiral symmetry of QCD has been restored. This leads to large imbalances in the production of charged to neutral pions. Sophisticated analysis methods are being developed to disentangle DCC events out of the large background of events with conventionally produced particles. We present a short review of current analysis methods and future prospects.Comment: 12 pages, 5 figures. Invited talk presented at the 13th International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 97), Tsukuba, Japan, 1-5 Dec 199
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