Gravitational radiation from precessing accretion disks in gamma-ray bursts

Context. We study the precession of accretion disks in the context of gamma-ray burst inner engines. Aims. Our aim is to quantitatively estimate the characteristics of gravitational waves produced by the precession of the transient accretion disk in gamma-ray bursts. Methods. We evaluate the possible periods of disk precession caused by the Lense-Thirring effect using an accretion disk model that allows for neutrino cooling. Assuming jet ejection perpendicular to the disk plane and a typical intrinsic time-dependence for the burst, we find gamma-ray light curves that have a temporal microstructure similar to that observed in some reported events. The parameters obtained for the precession are then used to evaluate the production of gravitational waves. Results. We find that the precession of accretion disks of outer radius smaller than 108 cm and accretion rates above 1 M⊙ s-1 could be detected by Advanced LIGO if they occur at distances of less than 100 Mpc. Conclusions. We conclude that the precession of a neutrino-cooled accretion disk in long gamma-ray bursts can be probed by gravitational wave astronomy. Precession of the disks in short gamma-ray events is undetectable with the current technology.Facultad de Ciencias Astronómicas y Geofísica

Sudden alteration in the seismic behavior of the Domuyo volcanic complex in the southern volcanic backarc zone, Argentina

The Domuyo volcanic complex (DVC) and its geothermal field in the retroarc zone of the southern Central Andes of Argentina present reduced seismicity according to different catalogs (USGS and INPRES). However, in 2015/2016, a local project was carried out in the area to describe its seismo-volcanic activity, registering a large number of volcano-tectonic (VT) events (538 VT). Considering there is scarce information on these events, this study focuses on analyzing the Domuyo Volcanic Complex (DVC) to assess its seismicity. Therefore, we installed a local seismological network in the study area and compared results with data registered by other authors. Four seismological networks were used, to obtain a more precise location of the seismic events and calculate the focal mechanisms of earthquakes with magnitudes greater than 2. For the first record of crustal seismicity detected by INPRES the September 10th, 2016 with a Ml 3.3, we calculated the focal mechanism with two possible solutions: a thrust solution with a strike component and a favored normal solution with a strike component. Additionally, we relocated the largest event in the Domuyo region on March 27th, 2019, with a magnitude of 4.4 (NEIC – USGS) and focal mechanism with a normal solution and a small strike component, obtaining a shallower depth of 3.9 km instead of 10 km. The new seismological data used in this paper, correspond to September 10th 2016, and two different time periods, the first comprising continuous data from March to April 2019, when the largest registered earthquake occurred in the Domuyo region, and the second from December 2019 to January 2021. At these periods, registered seismicity had magnitudes Ml between 1.9 and 2.8, and focal depths between 1.8 and 5.2 km. Four of these events count with focal mechanisms with extensional and limited strike-slip components that are tentatively linked to the known neotectonic structures affecting the western slope of the DVC. This seismic sequence agrees with previous proposals in which degasification from a magmatic body at shallow depths constitutes the trigger factor.Fil: Godoy, Laura Beatriz. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nacif Suvire, Silvina Valeria. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nacif, Andres Antonio. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Christiansen, Rodolfo Omar. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Álvarez, Orlando. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Gimenez, Mario Ernesto. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Folguera, Andrés. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geologicas. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

The taxonomic position of the pelagic 'staurozoan' Tessera gemmaria as a ceriantharian larva

Based on 16 specimens from the Southwestern Atlantic coast (Argentina and Brazil) we reinterpret the taxonomic position of Tessera gemmaria Goy, 1979, a stauromedusa considered as incertae sedis for a long time. Using external morphology histological preparations and molecular data (16S and COI) we conclude that T. gemmaria is an early stage of a cerinula,the long-lived planktonic larval stage of the Ceriantharia (Anthozoa).Tessera gemmaria Goy, 1979, a stauromedusa considered as incertae sedis for a long time. Using external morphology histological preparations and molecular data (16S and COI) we conclude that T. gemmaria is an early stage of a cerinula,the long-lived planktonic larval stage of the Ceriantharia (Anthozoa).Fil: Rodriguez, Carolina Soledad. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Marques, Antonio C.. Universidade de Sao Paulo; BrasilFil: Stampar, Sérgio N.. Universidade de Sao Paulo; BrasilFil: Morandini, André C.. Universidade de Sao Paulo; BrasilFil: Christiansen, Ernesto. Instituto Nacional de Investigaciones y Desarrollo Pesquero; ArgentinaFil: Genzano, Gabriel Nestor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Mianzan, Hermes Walter. Instituto Nacional de Investigaciones y Desarrollo Pesquero; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentin

Silos de Punta Quilla: uso potencial para mejorar los indicadores de la ganadería en Santa Cruz

En la actualidad existe suficiente conocimiento local generado a partir de experiencias en las que se han mejorado los indicadores típicos de producción mediante la mejora del plano nutricional a partir de suplementación estratégica en baches. Sin embargo, estas técnicas no han logrado expandirse o estar al alcance de la mayoría de los productores debido a la falta de capacidad financiera para invertir en la infraestructura necesaria, o incluso por el alto costo de los alimentos y flete. En ese contexto, el Gobierno Provincial a través del Consejo Agrario Provincial, ha puesto especial énfasis en la instalación de dos silos de 1500 toneladas cada uno en el puerto de Punta Quilla, localidad de Puerto Santa Cruz, a partir de lo cual los productores accederían a alimento transportado a granel por vía marítima y a un precio más bajo que el transportado por vía terrestre. Con el objeto de contribuir a la puesta en funcionamiento de este proyecto, y en línea con un pedido realizado por representantes de FIAS e IPG, se cuantificaron los volúmenes necesarios para realizar diferentes planteos de suplementaciones estratégicas en ovinos y bovinos, considerando el aporte de fibra a partir de forraje en los casos que fuera necesario. Para las estimaciones se tomó en cuenta el stock actualizado según SENASA, mientras que la determinación de los porcentajes a suplementar se basó en la experiencia previa y en un importante número de trabajos técnicos realizados por INTA Santa Cruz. Es importante señalar que la operación de los silos con alimento balanceado no sería una alternativa posible ya que para lograr las 3000 toneladas y eficientizar el transporte, varias plantas deberían fabricar un mismo tipo de alimento, el cual debiera acopiarse en puerto con un incremento en el costo del producto en destino. A esto, se le suman las pérdidas en el proceso de transporte, carga y descarga, y otros potenciales problemas asociadas a grandes volúmenes, que afectarían la calidad del alimento. En tal sentido, y aun siendo más riesgoso debido a la acidosis, evaluamos el uso de maíz como fuente de energía, y de expeler de soja como aportante de proteína, siendo necesario contemplar una planta para la formulación de alimentos, que permita alcanzar las especificaciones de energía y proteína requeridas en cada estrategia. En este documento no analizamos el transporte marítimo, la infraestructura y equipamiento en muelle para la correcta operación de los buques, ni la necesidad de infraestructura básica a campo para el manejo de alimento a granel, todos aspectos complementarios y fundamentales para implementar con éxito distintos esquemas de alimentación o suplementación estratégica.EEA Santa CruzFil: Milicevic, Francisco. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz. Agencia de Extensión Rural Río Gallegos; Argentina.Fil: Aguilar, Marcelo Javier. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz. Agencia de Extensión Rural San Julián; Argentina.Fil: Fernandez, Rodrigo Ernesto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz. Agencia de Extensión Rural El Calafate; Argentina.Fil: Rivera, Emilio Hernan. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz. Agencia de Extensión Rural Río Gallegos; Argentina.Fil: Sturzenbaum, Maria Virginia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz. Agencia de Extensión Rural Río Gallegos; Argentina.Fil: Mansilla José Javier. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz. Agencia de Extensión Rural El Calafate; Argentina.Fil: Christiansen, Rodolfo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz. Agencia de Extensión Rural Río Turbio; Argentina.Fil: Christiansen, Rodolfo. Universidad Nacional de la Patagonia Austral. Unidad Académica Río Turbio Santa Cruz; Argentina

Azimuthal anisotropy of charged jet production in root s(NN)=2.76 TeV Pb-Pb collisions

We present measurements of the azimuthal dependence of charged jet production in central and semi-central root s(NN) = 2.76 TeV Pb-Pb collisions with respect to the second harmonic event plane, quantified as nu(ch)(2) (jet). Jet finding is performed employing the anti-k(T) algorithm with a resolution parameter R = 0.2 using charged tracks from the ALICE tracking system. The contribution of the azimuthal anisotropy of the underlying event is taken into account event-by-event. The remaining (statistical) region-to-region fluctuations are removed on an ensemble basis by unfolding the jet spectra for different event plane orientations independently. Significant non-zero nu(ch)(2) (jet) is observed in semi-central collisions (30-50% centrality) for 20 <p(T)(ch) (jet) <90 GeV/c. The azimuthal dependence of the charged jet production is similar to the dependence observed for jets comprising both charged and neutral fragments, and compatible with measurements of the nu(2) of single charged particles at high p(T). Good agreement between the data and predictions from JEWEL, an event generator simulating parton shower evolution in the presence of a dense QCD medium, is found in semi-central collisions. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).Peer reviewe

Forward-central two-particle correlations in p-Pb collisions at root s(NN)=5.02 TeV

Two-particle angular correlations between trigger particles in the forward pseudorapidity range (2.5 2GeV/c. (C) 2015 CERN for the benefit of the ALICE Collaboration. Published by Elsevier B. V.Peer reviewe

Event-shape engineering for inclusive spectra and elliptic flow in Pb-Pb collisions at root(NN)-N-S=2.76 TeV

Peer reviewe

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Juxtaposing BTE and ATE – on the role of the European insurance industry in funding civil litigation

One of the ways in which legal services are financed, and indeed shaped, is through private insurance arrangement. Two contrasting types of legal expenses insurance contracts (LEI) seem to dominate in Europe: before the event (BTE) and after the event (ATE) legal expenses insurance. Notwithstanding institutional differences between different legal systems, BTE and ATE insurance arrangements may be instrumental if government policy is geared towards strengthening a market-oriented system of financing access to justice for individuals and business. At the same time, emphasizing the role of a private industry as a keeper of the gates to justice raises issues of accountability and transparency, not readily reconcilable with demands of competition. Moreover, multiple actors (clients, lawyers, courts, insurers) are involved, causing behavioural dynamics which are not easily predicted or influenced. Against this background, this paper looks into BTE and ATE arrangements by analysing the particularities of BTE and ATE arrangements currently available in some European jurisdictions and by painting a picture of their respective markets and legal contexts. This allows for some reflection on the performance of BTE and ATE providers as both financiers and keepers. Two issues emerge from the analysis that are worthy of some further reflection. Firstly, there is the problematic long-term sustainability of some ATE products. Secondly, the challenges faced by policymakers that would like to nudge consumers into voluntarily taking out BTE LEI