Dimensionally continued Oppenheimer-Snyder gravitational collapse II: solutions in odd dimensions

The Lovelock gravity extends the theory of general relativity to higher dimensions in such a way that the field equations remain of second order. The theory has many constant coefficients with no a priori meaning. Nevertheless it is possible to reduce them to two, the cosmological constant and Newton's constant. In this process one separates theories in even dimensions from theories in odd dimensions. In a previous work gravitational collapse in even dimensions was analysed. In this work attention is given to odd dimensions. It is found that black holes also emerge as the final state of gravitational collapse of a regular dust fluid.Comment: 16 pages, 3figures, latex Journal: to appear in Journal of Mathematical Physic

Dimensionally continued Oppenheimer-Snyder gravitational collapse. I - solutions in even dimensions

The extension of the general relativity theory to higher dimensions, so that the field equations for the metric remain of second order, is done through the Lovelock action. This action can also be interpreted as the dimensionally continued Euler characteristics of lower dimensions. The theory has many constant coefficients apparently without any physical meaning. However, it is possible, in a natural way, to reduce to two (the cosmological and Newton's constant) these several arbitrary coefficients, yielding a restricted Lovelock gravity. In this process one separates theories in even dimensions from theories in odd dimensions. These theories have static black hole solutions. In general relativity, black holes appear as the final state of gravitational collapse. In this work, gravitational collapse of a regular dust fluid in even dimensional restricted Lovelock gravity is studied. It is found that black holes emerge as the final state for these regular initial conditions.Comment: Late

Interference Phenomenon for the Faddeevian Regularization of 2D Chiral Fermionic Determinants

The classification of the regularization ambiguity of 2D fermionic determinant in three different classes according to the number of second-class constraints, including the new faddeevian regularization, is examined and extended. We found a new and important result that the faddeevian class, with three second-class constraints, possess a free continuous one parameter family of elements. The criterion of unitarity restricts the parameter to the same range found earlier by Jackiw and Rajaraman for the two-constraints class. We studied the restriction imposed by the interference of right-left modes of the chiral Schwinger model ($\chi QED_{2}$) using Stone's soldering formalism. The interference effects between right and left movers, producing the massive vectorial photon, are shown to constrain the regularization parameter to belong to the four-constraints class which is the only non-ambiguous class with a unique regularization parameter.Comment: 15 pages, Revtex. Final version to be published in Phys. Rev.

Análise estratégica da cadeia produtiva de leite ovino no Brasil: uma abordagem pela metodologia SWOT

O leite ovino é utilizado em escala global para a produção de queijos e outros derivados, ou para consumo in natura. A produção de leite e de seus derivados, seja formal ou informal, faz parte de uma cadeia produtiva, com menor ou maior grau de organização dependendo do desenvolvimento regional da atividade. O objetivo deste estudo foi descrever e discutir os elementos da cadeia produtiva de leite ovino no Brasil utilizando a metodologia SWOT. Este estudo foi desenvolvido em 2017 a partir de pesquisa direta com agentes ligados ao setor produtivo de leite ovino de 15 propriedades distribuídas em sete Estados do Brasil. Os agentes apontaram e descreveram os pontos fortes e fracos, as oportunidades e ameaças dos segmentos de insumos, produção, processamento, e venda e distribuição de produtos e, posteriormente, esses elementos foram organizados em uma matriz SWOT. No segmento produção, a baixa adoção de técnicas adequadas de produção, controle de dados e conhecimento dos custos de produção são fatores críticos. No segmento processamento, aspectos positivos foram apontados para as características físico-químicas do leite ovino, enquanto aspectos relacionados com a legislação foram considerados pontos críticos. A falta de cultura e conhecimento do consumidor sobre os produtos derivados do leite ovino são pontos críticos que afetam o segmento de venda e distribuição. A pequena escala de produção e a baixa demanda pelo leite e seus derivados, assim como a falta de insumos específicos para a atividade, também são pontos críticos da cadeia produtiva. Entretanto, o uso de insumos de outras atividades pecuárias (principalmente da bovinocultura leiteira) é uma opção importante para reduzir os custos de produção e otimizar o uso dos recursos na ovinocultura leiteira. Técnicas adequadas de produção e de processamento do leite ovino devem ser implementadas, assim como o controle de dados e de custos da produção. Apesar dos sistemas de produção estudados serem heterogêneos, alguns apresentam indicadores econômicos positivos, o que demonstra o potencial produtivo e econômico da atividade. Nesse cenário, a produção intensiva de produtos com maior valor agregado e o crescimento do mercado consumidor são fatores que estimulam o crescimento da ovinocultura leiteira, e são considerados oportunidades, de modo que campanhas de marketing para promover o consumo de derivados do leite devem ser realizadas. O pequeno volume de leite produzido gera oportunidades ao setor pela falta de concorrência e pelo grande mercado potencial a ser explorado, especialmente nos grandes centros, com maior poder aquisitivo

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected

The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in July 2014. It pursues three core programs: APOGEE-2,MaNGA, and eBOSS. In addition, eBOSS contains two major subprograms: TDSS and SPIDERS. This paper describes the first data release from SDSS-IV, Data Release 13 (DR13), which contains new data, reanalysis of existing data sets and, like all SDSS data releases, is inclusive of previously released data. DR13 makes publicly available 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA,the first data released from this survey. It includes new observations from eBOSS, completing SEQUELS. In addition to targeting galaxies and quasars, SEQUELS also targeted variability-selected objects from TDSS and X-ray selected objects from SPIDERS. DR13 includes new reductions ofthe SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification. DR13 releases new reductions of the APOGEE-1data from SDSS-III, with abundances of elements not previously included and improved stellar parameters for dwarf stars and cooler stars. For the SDSS imaging data, DR13 provides new, more robust and precise photometric calibrations. Several value-added catalogs are being released in tandem with DR13, in particular target catalogs relevant for eBOSS, TDSS, and SPIDERS, and an updated red-clump catalog for APOGEE.This paper describes the location and format of the data now publicly available, as well as providing references to the important technical papers that describe the targeting, observing, and data reduction. The SDSS website, http://www.sdss.org, provides links to the data, tutorials and examples of data access, and extensive documentation of the reduction and analysis procedures. DR13 is the first of a scheduled set that will contain new data and analyses from the planned ~6-year operations of SDSS-IV.PostprintPeer reviewe