The Distribution of Alpha Elements in Ultra-Faint Dwarf Galaxies

The Milky Way ultra-faint dwarf galaxies (UFDs) contain some of the oldest, most metal-poor stars in the Universe. We present [Mg/Fe], [Si/Fe], [Ca/Fe], [Ti/Fe], and mean [alpha/Fe], abundance ratios for 61 individual red giant branch stars across 8 UFDs. This is the largest sample of alpha abundances published to date in galaxies with absolute magnitudes M_V > -8, including the first measurements for Segue 1, Canes Venatici II, Ursa Major I, and Leo T. Abundances were determined via medium-resolution Keck/DEIMOS spectroscopy and spectral synthesis. The sample spans the metallicity range -3.4 < [Fe/H] < -1.1. With the possible exception of Segue 1 and Ursa Major II, the individual UFDs show on average lower [alpha/Fe] at higher metallicities, consistent with enrichment from Type Ia supernovae. Thus even the faintest galaxies have undergone at least a limited level of chemical self-enrichment. Together with recent photometric studies, this suggests that star formation in the UFDs was not a single burst, but instead lasted at least as much as the minimum time delay of the onset of Type Ia supernovae (~100 Myr) and less than ~2 Gyr. We further show that the combined population of UFDs has an [alpha/Fe] abundance pattern that is inconsistent with a flat, Galactic halo-like alpha abundance trend, and is also qualitatively different from that of the more luminous CVn I dSph, which does show a hint of a plateau at very low [Fe/H].Comment: 14 pages, 6 figures, re-submitted to ApJ with revisions based on referee repor

Localised anti-branes in non-compact throats at zero and finite T

We investigate the 3-form singularities that are typical to anti-brane solutions in supergravity and check whether they can be cloaked by a finite temperature horizon. For anti-D3-branes in the Klebanov-Strassler background, this was already shown numerically to be impossible when the branes are partially smeared. In this paper, we present analytic arguments that also localised branes remain with singular 3-form fluxes at both zero and finite temperature. These results may have important, possibly fatal, consequences for constructions of meta-stable de Sitter vacua through uplifting.Comment: 18 + 9 page

Estudio de la demanda de energía eléctrica en edificios universitarios para su abastecimiento parcial con generación fotovoltaica

Los edificios educativos del Nordeste Argentino presentan características adecuadas al momento de considerar la implementación de un suministro parcial de electricidad por generación fotovoltaica. Se exponen los primeros resultados del análisis y caracterización de la demanda de energía eléctrica en edificios universitarios de la región para determinar el impacto sobre la misma de un sistema de generación fotovoltaica. Se comenzó realizando un estudio del consumo eléctrico a fin de describir sus características y detectar ineficiencias que puedan subsanarse antes de implementar la generación renovable. Este estudio se extiende a cinco Facultades localizadas en la ciudad de Resistencia. Cuatro de ellas pertenecientes a la Universidad Nacional del Nordeste y la restante perteneciente a la Universidad Tecnológica Nacional. Con esta información se procede a diseñar y dimensionar un sistema de generación fotovoltaica determinándose la porción de la demanda que se podrá satisfacer.Educational buildings in the Northeast of Argentina present adequate characteristics at the moment of considering the implementation of partial electricity supply by photovoltaic generation. First results of the analysis and characterization of the demand of electric energy in university buildings of the region are presented, to determine the impact of a photovoltaic generation system on it. It began by conducting a study of electricity consumption in order to describe its characteristics and to detect inefficiencies that can be remedied before implementing renewable generation. This study extends to five Faculties located in the city of Resistencia. Four of them belonging to the Universidad Nacional del Nordeste and the last one belonging to the Universidad Tecnológica Nacional. With this information it proceeds to design and size a photovoltaic generation system, determining the portion of the demand that can be satisfied.Fil: Zurlo, Hugo D.. Universidad Tecnológica Nacional (Argentina). Facultad Regional ResistenciaFil: Vargas, Orlando C.. Universidad Tecnológica Nacional (Argentina). Facultad Regional Resistenci

The global addiction academy project: a global phenomenon - requiring a global solution - from a global community

The emergence of different and effective modes of e-communications has rapidly expanded possibilities for more extensive dialogue, collaboration and learning. For professionals and those working with addiction issues and support services, these offer increased opportunities to break down significant barriers to integrating issues of addiction into the care sector workforce and to ensure that the workforce can respond more appropriately and confidently and to access a range of up-to-date resources as well as to share best practice and expertise. Our international collaboration to develop a Global Classroom which started at the beginning of 2014 seeks to provide an innovative online platform for stimulating learning among people of different disciplines and interests on addictions. We aim to bring people together from diverse cultural communities to engage in dialogue, debate and to share ideas on addiction beyond their own peers, regions or country and to meet a range of learning needs within this structure which is inclusive and developmental. This symposium will share the outcomes of our early developments in the first year of developing a global addiction academy project, the challenges and possibilities particularly focusing on the impact of such methodology on achieving wider engagement on a global public health issue and enhancing inter-professional learning

Inter-band B(E2) transition strengths in odd-mass heavy deformed nuclei

Inter-band B(E2) transition strengths between different normal parity bands in 163Dy and 165Er are described using the pseudo-SU(3) model. The Hamiltonian includes Nilsson single-particle energies, quadrupole-quadrupole and pairing interactions with fixed, parametrized strengths, and three extra rotor terms used to fine tune the energy spectra. In addition to inter-band transitions, the energy spectra and the ground state intra-band B(E2) strengths are reported. The results show the pseudo-SU(3) shell model to be a powerful microscopic theory for a description of the normal parity sector in heavy deformed odd-A nuclei.Comment: 4 figures, 2 table

Gause's exclusion principle revisited: artificial modified species and competition

Gause's principle of competition between two species is studied when one of them is sterile. We study the condition for total extinction in the niche, namely, when the sterile population exterminates the native one by an optimal use of resources. A mathematical Lotka-Volterra non linear model of interaction between a native and sterile species is proposed. The condition for total extinction is related to the initial number $M_{o}$ of sterile individuals released in the niche. In fact, the existence of a critical sterile-population value $M_{c}$ is conjectured from numerical analysis and an analytical estimation is found. When spatial diffusion (migration) is considered a critical size territory is found and, for small territory, total extinction exist in any case. This work is motived by the extermination agriculture problem of fruit flies in our region.Comment: 11 pages. Published in Jour.Phys.A Math.Gen. 33, 4877 (2000

A Light Calibration System for the ProtoDUNE-DP Detector

A LED-based fiber calibration system for the ProtoDUNE-Dual Phase (DP) photon detection system (PDS) has been designed and validated. ProtoDUNE-DP is a 6x6x6 m3 liquid argon time-projection-chamber currently being installed at the Neutrino Platform at CERN. The PDS is based on 36 8-inch photomultiplier tubes (PMTs) and will allow triggering on cosmic rays. The system serves as prototype for the PDS of the final DUNE DP far detector in which the PDS also has the function to allow the 3D event reconstruction on non-beam physics. For this purpose an equalized PMT response is desirable to allow using the same threshold definition for all PMT groups, simplifying the determination of the trigger efficiency. The light calibration system described in this paper is developed to provide this and to monitor the PMT performance in-situ.Comment: 15 pages, 5 figure