Parámetros ambientales y pesqueros de un lago somero de La Pampa, luego de una mortandad masiva de <i>Odontesthes bonariensis</i>

The Bajo Giuliani Lagoon (36 ° 42 ‘20’’ S, 64 ° 16 ‘ 02 ‘’ W) is located south of the city of Santa Rosa, La Pampa, which was stocked with fish during the late 90’s. In this hypertrophic shallow lake, major environmental changes caused mass mortalities of silverside Odontesthes bonariensis, the last one occurred in 2010. In order to know the current state of the environment, in April 2013 surface water samples were collected, several points were georeferenced and major morphometric parameters were estimated. Fish were captured by trawls and gillnets. The lake has an area of 965 ha with an average depth of 2.31 meters, hyposaline, hard and sodium chlorinated water. Captured register 549 specimens of O. bonariensis and 437 of Jenynsia multidentata, showing a low diversity. The captured silverside ranged from 75 to 343 mm standard length and from 4 to 568 grams. The catch per unit effort in number and biomass was 519 fishes/ night and 99.2 kilos / night respectively, and the trophy size (PSD) was 41.6 6 %. The results indicate that PSD was 16% lower than those recorded before mortality in October 2009. Also, CPUE in number and CPUE in weight obtained were lower than that date. Nevertheless, several index showed better current body conditions.Facultad de Ciencias Naturales y Muse

Parámetros ambientales y pesqueros de un lago somero de La Pampa, luego de una mortandad masiva de <i>Odontesthes bonariensis</i>

The Bajo Giuliani Lagoon (36 ° 42 ‘20’’ S, 64 ° 16 ‘ 02 ‘’ W) is located south of the city of Santa Rosa, La Pampa, which was stocked with fish during the late 90’s. In this hypertrophic shallow lake, major environmental changes caused mass mortalities of silverside Odontesthes bonariensis, the last one occurred in 2010. In order to know the current state of the environment, in April 2013 surface water samples were collected, several points were georeferenced and major morphometric parameters were estimated. Fish were captured by trawls and gillnets. The lake has an area of 965 ha with an average depth of 2.31 meters, hyposaline, hard and sodium chlorinated water. Captured register 549 specimens of O. bonariensis and 437 of Jenynsia multidentata, showing a low diversity. The captured silverside ranged from 75 to 343 mm standard length and from 4 to 568 grams. The catch per unit effort in number and biomass was 519 fishes/ night and 99.2 kilos / night respectively, and the trophy size (PSD) was 41.6 6 %. The results indicate that PSD was 16% lower than those recorded before mortality in October 2009. Also, CPUE in number and CPUE in weight obtained were lower than that date. Nevertheless, several index showed better current body conditions.Facultad de Ciencias Naturales y Muse

Search for astronomical neutrinos from blazar TXS 0506+056 in super-kamiokande

We report a search for astronomical neutrinos in the energy region from several GeV to TeV in the direction of the blazar TXS 0506+056 using the Super-Kamiokande detector following the detection of a 100 TeV neutrinos from the same location by the IceCube collaboration. Using Super-Kamiokande neutrino data across several data samples observed from 1996 April to 2018 February we have searched for both a total excess above known backgrounds across the entire period as well as localized excesses on smaller timescales in that interval. No significant excess nor significant variation in the observed event rate are found in the blazar direction. Upper limits are placed on the electron- and muon-neutrino fluxes at the 90% confidence level as 6.0 × 10−7 and 4.5 × 10−7–9.3 × 10−10 [erg cm−2 s−1], respectively

Measurements of and + charged-current cross-sections without detected pions or protons on water and hydrocarbon at a mean anti-neutrino energy of 0.86 GeV

We report measurements of the flux-integrated and + charged-current cross-sections on water and hydrocarbon targets using the T2K anti-neutrino beam with a mean beam energy of 0.86 GeV. The signal is defined as the (anti-)neutrino charged-current interaction with one induced and no detected charged pion or proton. These measurements are performed using a new WAGASCI module recently added to the T2K setup in combination with the INGRID Proton Module. The phase space of muons is restricted to the high-detection efficiency region, 400 and 30 , in the laboratory frame. An absence of pions and protons in the detectable phase spaces of 200, 70 and 600, 70 is required. In this paper, both the; cross-sections and +; cross-sections on water and hydrocarbon targets and their ratios are provided by using the D\u27Agostini unfolding method. The results of the integrated ; cross-section measurements over this phase space are ;\sigma{\rm H{2}O}=(1.082\pm0.068(\rm stat.) {+0.145}{-0.128}(\rm syst.)) \times 10 {-39}\,{\rm cm {2} / nucleon};, ;\sigma{\rm CH}=(1.096\pm0.054(\rm stat.) {+0.132}{-0.117}(\rm syst.)) \times 10 {-39}\,{\rm cm {2} / nucleon};, and ;\sigma{\rm H{2}O}/\sigma{\rm CH} = 0.987\pm0.078(\rm stat.) {+0.093}{-0.090}(\rm syst.);. The +; cross-section is ;\sigma{\rm H{2}O} = (1.155\pm0.064(\rm stat.) {+0.148}{-0.129}(\rm syst.)) \times 10 {-39}\,{\rm cm {2} / nucleon};, ;\sigma{\rm CH}=(1.159\pm0.049(\rm stat.) {+0.129}{-0.115}(\rm syst.)) \times 10 {-39}\,{\rm cm {2} / nucleon};, and ;\sigma{\rm H{2}O}/\sigma{\rm CH}=0.996\pm0.069(\rm stat.) {+0.083}{-0.078}(\rm syst.);

The SOX experiment in the neutrino physics

SOX (Short distance neutrino Oscillations with BoreXino) is a new experiment that takes place at the Laboratori Nazionali del Gran Sasso (LNGS) and it exploits the Borexino detector to study the neutrino oscillations at short distance. In different phases, by using two artificial sources Cr-51 and Ce-144-Pr-144, neutrino and antineutrino fluxes of measured intensity will be detected by Borexino in order to observe possible neutrino oscillations in the sterile state. In this paper an overview of the experiment is given and one of the two calorimeters that will be used to measure the source activity is described. At the end the expected sensitivity to determine the neutrino sterile mass is shown

Search for proton decay into three charged leptons in 0.37 megaton-years exposure of the Super-Kamiokande

A search for proton decay into three charged leptons has been performed by using 0.37 Mton⋅years of data collected in Super-Kamiokande. All possible combinations of electrons, muons, and their antiparticles consistent with charge conservation were considered as decay modes. No significant excess of events has been found over the background, and lower limits on the proton lifetime divided by the branching ratio have been obtained. The limits range between 9.2×10^33 and 3.4×10^34 years at 90% confidence level, improving by more than an order of magnitude upon limits from previous experiments. A first limit has been set for the p→μ^−e^+e^+ mode

Search for astronomical neutrinos from blazar TXS 0506+056 in Super-Kamiokande

We report a search for astronomical neutrinos in the energy region from several GeV to TeV in the direction of the blazar TXS 0506+056 using the Super-Kamiokande detector following the detection of a 100 TeV neutrinos from the same location by the IceCube collaboration. Using Super-Kamiokande neutrino data across several data samples observed from 1996 April to 2018 February we have searched for both a total excess above known backgrounds across the entire period as well as localized excesses on smaller timescales in that interval. No significant excess nor significant variation in the observed event rate are found in the blazar direction. Upper limits are placed on the electron- and muon-neutrino fluxes at the 90% confidence level as 6.0 × 10−7 and 4.5 × 10−7–9.3 × 10−10 [erg cm−2 s−1], respectively