419 research outputs found

    CALONECTRIS BOREALIS (AVES, PROCELLARIIDAE) COMO UN REGISTRO NUEVO PARA DOS ESPECIES DE NEMÁTODOS EN BRASIL

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    Contracaecum pelagicum Johnston & Mawson, 1942 y Seuratia shipleyi (Stossich, 1900) están registrados en Brasil parasitando Calonectris borealis (Cory, 1881), que es un nuevo huésped para ambas especies. Se presentam las principales medidas de estas especies en el nuevo huésped

    Suitability Analysis of Groundwater for Eco-friendly Agricultural Growths in Food Basket of Pakistan

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    Water is an important component of earth’s atmosphere and it sustains ecosystems, agriculture and human settlements on earth (Samson et al., 2010). Salinity, sodicity and toxicity generally need to be considered for the evaluation of suitable quality of groundwater for irrigation (Khan et al., 2014; Cobbina et al., 2012; Todd and Mays, 2005). In Thal Doab Aquifer (TDA) groundwater occurs as a layer of fresh water over saline water and its availability is subjected to recharging potency of the Indus and Chenab rivers (Hussain et al., 2017 a, 2016 a)

    Geometric Thermodynamics of Schwarzschild-AdS black hole with a Cosmological Constant as State Variable

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    The thermodynamics of the Schwarzschild-AdS black hole is reformulated within the context of the recently developed formalism of geometrothermodynamics (GTD). Different choices of the metric in the equilibrium states manifold are used in order to reproduce the Hawking-Page phase transition as a divergence of the thermodynamical curvature scalar. We show that the enthalpy and total energy representations of GTD does not reproduce the transition while the entropy rep- resentation gives the expected behavior.Comment: 14 page

    LISTA DE CESTODA DO BRASIL

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    Se presenta una lista completa de las 432 especies de Cestoda que se han descrito y / o registrados en Brasil. Se distribuyen através de 15 órdenes y 36 familias; 50 especies no fueron identificadas y 9 se consideran species inquirenda. Entre los peces, Zungaro zungaro (Humboldt in Humboldt & Valenciennes, 1821) fue el hospedador que fue más parasitadas (con 18 especies de cestodos); entre los anfibios, fue Rhinella icterica Spix, 1824, con 3 especies; y entre los reptiles, fue Bothrops jararaca (Wied-Neuwied, 1824), con 7 especies. Entre las aves, Gallus gallus (Linnaeus, 1758) presentó el mayor numero de asociaciones con cestodos, de tal manera que 13 especies se han registrado en Brasil y teniendo en cuenta los mamíferos, Homo sapiens (Linnaeus, 1758) presentan 13 especies diferentes. Pocos representantes de estas especies de cestode se reportaran de invertebrados. El pequeño número de los helmintos parásitos descritos es probablemente debido al submuestreo de hospedadores potenciales, junto con el pequeño número de expertos en la taxonomía de los parásitos

    Calibration of the Logarithmic-Periodic Dipole Antenna (LPDA) Radio Stations at the Pierre Auger Observatory using an Octocopter

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    An in-situ calibration of a logarithmic periodic dipole antenna with a frequency coverage of 30 MHz to 80 MHz is performed. Such antennas are part of a radio station system used for detection of cosmic ray induced air showers at the Engineering Radio Array of the Pierre Auger Observatory, the so-called Auger Engineering Radio Array (AERA). The directional and frequency characteristics of the broadband antenna are investigated using a remotely piloted aircraft (RPA) carrying a small transmitting antenna. The antenna sensitivity is described by the vector effective length relating the measured voltage with the electric-field components perpendicular to the incoming signal direction. The horizontal and meridional components are determined with an overall uncertainty of 7.4^{+0.9}_{-0.3} % and 10.3^{+2.8}_{-1.7} % respectively. The measurement is used to correct a simulated response of the frequency and directional response of the antenna. In addition, the influence of the ground conductivity and permittivity on the antenna response is simulated. Both have a negligible influence given the ground conditions measured at the detector site. The overall uncertainties of the vector effective length components result in an uncertainty of 8.8^{+2.1}_{-1.3} % in the square root of the energy fluence for incoming signal directions with zenith angles smaller than 60{\deg}.Comment: Published version. Updated online abstract only. Manuscript is unchanged with respect to v2. 39 pages, 15 figures, 2 table

    Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory

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    We report a multi-resolution search for anisotropies in the arrival directions of cosmic rays detected at the Pierre Auger Observatory with local zenith angles up to 8080^\circ and energies in excess of 4 EeV (4×10184 \times 10^{18} eV). This search is conducted by measuring the angular power spectrum and performing a needlet wavelet analysis in two independent energy ranges. Both analyses are complementary since the angular power spectrum achieves a better performance in identifying large-scale patterns while the needlet wavelet analysis, considering the parameters used in this work, presents a higher efficiency in detecting smaller-scale anisotropies, potentially providing directional information on any observed anisotropies. No deviation from isotropy is observed on any angular scale in the energy range between 4 and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured; while no other deviation from isotropy is observed for moments beyond the dipole one. The corresponding pp-values obtained after accounting for searches blindly performed at several angular scales, are 1.3×1051.3 \times 10^{-5} in the case of the angular power spectrum, and 2.5×1032.5 \times 10^{-3} in the case of the needlet analysis. While these results are consistent with previous reports making use of the same data set, they provide extensions of the previous works through the thorough scans of the angular scales.Comment: Published version. Added journal reference and DOI. Added Report Numbe

    Ultrahigh-energy neutrino follow-up of Gravitational Wave events GW150914 and GW151226 with the Pierre Auger Observatory

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    On September 14, 2015 the Advanced LIGO detectors observed their first gravitational-wave (GW) transient GW150914. This was followed by a second GW event observed on December 26, 2015. Both events were inferred to have arisen from the merger of black holes in binary systems. Such a system may emit neutrinos if there are magnetic fields and disk debris remaining from the formation of the two black holes. With the surface detector array of the Pierre Auger Observatory we can search for neutrinos with energy above 100 PeV from point-like sources across the sky with equatorial declination from about -65 deg. to +60 deg., and in particular from a fraction of the 90% confidence-level (CL) inferred positions in the sky of GW150914 and GW151226. A targeted search for highly-inclined extensive air showers, produced either by interactions of downward-going neutrinos of all flavors in the atmosphere or by the decays of tau leptons originating from tau-neutrino interactions in the Earth's crust (Earth-skimming neutrinos), yielded no candidates in the Auger data collected within ±500\pm 500 s around or 1 day after the coordinated universal time (UTC) of GW150914 and GW151226, as well as in the same search periods relative to the UTC time of the GW candidate event LVT151012. From the non-observation we constrain the amount of energy radiated in ultrahigh-energy neutrinos from such remarkable events.Comment: Published version. Added journal reference and DOI. Added Report Numbe

    A search for point sources of EeV photons

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    Measurements of air showers made using the hybrid technique developed with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for point sources of EeV photons anywhere in the exposed sky. A multivariate analysis reduces the background of hadronic cosmic rays. The search is sensitive to a declination band from -85{\deg} to +20{\deg}, in an energy range from 10^17.3 eV to 10^18.5 eV. No photon point source has been detected. An upper limit on the photon flux has been derived for every direction. The mean value of the energy flux limit that results from this, assuming a photon spectral index of -2, is 0.06 eV cm^-2 s^-1, and no celestial direction exceeds 0.25 eV cm^-2 s^-1. These upper limits constrain scenarios in which EeV cosmic ray protons are emitted by non-transient sources in the Galaxy.Comment: 28 pages, 10 figures, accepted for publication in The Astrophysical Journa
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