11,131 research outputs found

    Science highlights from the Fermi Large Area Telescope

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    During its first three years of operation, the Fermi Gamma-ray Space Telescope has provided an unprecedented view of the high energy gamma-ray sky, and also performed direct measurements of the cosmic-ray leptons and searches for signals from dark matter. In this paper we present a short overview of some highlight results, shedding new light on the high-energy side of the Universe.Comment: Contribution to Les Rencontres de Physique de la Vall\'ee D'Aoste (La Thuile, February 27-March 5 2011); 12 pages, 5 figure

    Plasduino: An inexpensive, general-purpose data acquisition framework for educational experiments

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    Based on the Arduino development platform, plasduino is an opensource data acquisition framework specifically designed for educational physics experiments. The source code, schematics and documentation are in the public domain under a GPL license and the system, streamlined for low cost and ease of use, can be replicated on the scale of a typical didactic lab with minimal effort. We describe the basic architecture of the system and illustrate its potential with some real-life examples

    Mass formula for T=0 and T=1 ground states of N=Z nuclei

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    An algebraic model is developed to calculate the T=0 and T=1 ground state binding energies for N=Z nuclei. The method is tested in the sd shell and is then extended to 28-50 shell which is currently the object of many experimental studies.Comment: 5 figure

    Increasing Performances of TCP Data Transfers Through Multiple Parallel Connections

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    Although Transmission Control Protocol (TCP) is a widely deployed and successful protocol, it shows some limitations in present-day environments. In particular, it is unable to exploit multiple (physical or logical) paths between two hosts. This paper presents PATTHEL, a session-layer solution designed for parallelizing stream data transfers. Parallelization is achieved by striping the data flow among multiple TCP channels. This solution does not require invasive changes to the networking stack and can be implemented entirely in user space. Moreover, it is flexible enough to suit several scenarios - e.g. it can be used to split a data transfer among multiple relays within a peer-to-peer overlay networ

    Odd Parity Light Baryon Resonances

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    We use a consistent SU(6) extension of the meson-baryon chiral Lagrangian within a coupled channel unitary approach in order to calculate the T-matrix for meson-baryon scattering in s-wave. The building blocks of the scheme are the pion and nucleon octets, the rho nonet and the Delta decuplet. We identify poles in this unitary T-matrix and interpret them as resonances. We study here the non exotic sectors with strangeness S=0,-1,-2,-3 and spin J=1/2, 3/2 and 5/2. Many of the poles generated can be associated with known N, Delta, Sigma, Lambda and Xi resonances with negative parity. We show that most of the low-lying three and four star odd parity baryon resonances with spin 1/2 and 3/2 can be related to multiplets of the spin-flavor symmetry group SU(6). This study allows us to predict the spin-parity of the Xi(1620), Xi(1690), Xi(1950), Xi(2250), Omega(2250) and Omega(2380) resonances, which have not been determined experimentally yet.Comment: New appendix and references adde

    The Origanum Collection of Gaetano Savi (1769-1844) in the Herbarium Horti Pisani (PI)

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    The Origanum Collection of Gaetano Savi (1769-1844) in the Herbarium Horti Pisani (PI). The collection of exsiccata of the genus Origanum, studied by Gaetano Savi and kept in the Herbarium Horti Pisani (PI) represents a valuable document of Savi's work as a taxonomist. It provides useful news for researchers of systematics and history of botany. The collection is enriched by some original drawings and includes the lectotypes of Origanum confertum Savi and O. fortuitum Savi

    Lectotypification of two Origanum names (Lamiaceae) described by Gaetano Savi

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    Origanum confertum Savi and O. fortuitum Savi are typified on herbarium specimens kept in PI. These taxa are identifiable, as heterotypic synonyms, with O. majorana L. and O. xpaniculatum W.D.J.Koch, respectively
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