4,979 research outputs found
The Structure of AdS Black Holes and Chern Simons Theory in 2+1 Dimensions
We study anti-de Sitter black holes in 2+1 dimensions in terms of Chern
Simons gauge theory of anti-de Sitter group coupled to a source. Taking the
source to be an anti-de Sitter state specified by its Casimir invariants, we
show how all the relevant features of the black hole are accounted for. The
requirement that the source be a unitary representation leads to a discrete
tower of states which provide a microscopic model for the black hole.Comment: 17 pages, LaTex. The presentation in Section 5 was improved; other
minor improvements. Final form of the manuscrip
Educators’ Impression Construction: Considering Perceived Social Media Missteps
Social Media (SM) provide exciting instructional opportunities for educators. However, a simple Internet search reveals professional implications that have resulted from educators’ SM usage perceived as missteps. In this research, using an impression construction lens, we considered cases of educators’ SM missteps as perceived by stakeholders and as presented in the news media. From this analysis, a description of what is perceived as inappropriate teacher SM use is provided, explanations of the highlighted SM usage are considered, and a discussion of findings from an impression construction perspective is included. Results suggest impression construction in SM settings is a complex endeavor for educators that prompts varying opinions from stakeholder groups. Suggestions for professional SM use are included
AUDIODESCRIÇÃO: UM ESTUDO SOBRE O ACESSO ÀS IMAGENS POR PESSOAS COM DEFICIÊNCIA VISUAL NO ESTADO DO ESPÍRITO SANTO
Tese de doutorado com foco na audiodescrição, vinculada ao Programa de Pós-Graduação em Educação do Centro de Educação da Universidade Federal do Espírito Santo. Problematiza o acesso às imagens por pessoas com deficiência visual como direito à cidadania. A pesquisa qualitativa, ocorreu entre 2014 e 2017, no Instituto Luiz Braille do Espírito Santo, no Centro de Apoio Pedagógico (CAP) e no Centro Cultural Sesc Glória, todos em Vitória ES, com a participação de pessoas com deficiência visual de municípios do Espírito Santo, como Vitória, Vila Velha, Cariacica, Serra, Linhares e Aracruz. Procurou responder à pergunta: Como a audiodescrição, enquanto exercício exotópico, pode mediar o acesso às imagens por pessoas com deficiência visual e como isso se produz no Estado do Espírito Santo? Estabeleceu interlocução com Bakhtin, para dialogar sobre mediação, alteridade e exotopia; Walter Benjamin, para o estudo sobre Tradução e Reprodutibilidade Técnica, Schutz-Foerste e Ciavatta, para questões imagéticas, Oliver Sacks na análise das relações entre a pessoa com deficiência visual e o mundo imagético. Em especial, fundamentou-se nos diálogos com os sujeitos de pesquisa, pessoas com deficiência visual, dentre elas, a consultora de audiodescrição Aparecida Pereira Leite, que validou a audiodescrição das imagens apresentadas nesta tese e enriqueceu nosso estudo com seus depoimentos; além dos sujeitos do Instituto Luiz Braille, do Centro de Apoio Pedagógico (CAP) e dos espectadores da peça Ensaio Geral, provenientes de municípios diversos do estado do Espírito Santo. Nossas experiências e análises nos levaram a defender a tese de que a audiodescrição é uma prática incipiente no Estado do Espírito Santo e sua implementação e otimização impõe a necessidade do diálogo, na perspectiva da exotopia bakhtiniana. Busca possibilidades de realizar a mediação imagética com cegos, para além da tradução, mimésis ou interpretação
Comparison of nucleic acid extraction platforms for detection of select biothreat agents for use in clinical resource limited settings
High-quality nucleic acids are critical for optimal PCR-based diagnostics and pathogen detection. Rapid sample processing time is important for the earliest administration of therapeutic and containment measures, especially in the case of biothreat agents. In this context, we compared the Fujifilm QuickGene-Mini80 to Qiagen\u27s QIAamp Mini Purification kits for extraction of DNA and RNA for potential use in austere settings. Qiagen (QIAamp) column-based extraction is the currently recommended purification platform by United States Army Medical Research Institute for Infectious Diseases for both DNA and RNA extraction. However, this sample processing system requires dedicated laboratory equipment including a centrifuge. In this study, we investigated the QuickGene-Mini80, which does not require centrifugation, as a suitable platform for nucleic acid extraction for use in resource-limited locations. Quality of the sample extraction was evaluated using pathogen-specific, real-time PCR assays for nucleic acids extracted from viable and γ-irradiated Bacillus anthracis, Yersinia pestis, vaccinia virus, Venezuelan equine encephalitis virus, or B. anthracis spores in buffer or human whole blood. QuickGene-Mini80 and QIAamp performed similarly for DNA extraction regardless of organism viability. It was noteworthy that γ-irradiation did not have a significant impact on real-time PCR for organism detection. Comparison with QIAamp showed a less than adequate performance of the Fujifilm instrument for RNA extraction. However, QuickGene-Mini80 remains a viable alternative to QIAamp for DNA extraction for use in remote settings due to extraction quality, time efficiency, reduced instrument requirements, and ease of use
The s-process branching at 185W
The neutron capture cross section of the unstable nucleus 185W has been
derived from experimental photoactivation data of the inverse reaction
186W(gamma,n)185W. The new result of sigma = (687 +- 110) mbarn confirms the
theoretically predicted neutron capture cross section of 185W of sigma = 700
mbarn at kT = 30 keV. A neutron density in the classical s-process of n_n =
(3.8 +0.9 -0.8} * 1e8 cm-3 is derived from the new data for the 185W branching.
In a stellar s-process model one finds a significant overproduction of the
residual s-only nucleus 186Os.Comment: ApJ, in pres
Integrated Structure and Semantics for Reo Connectors and Petri Nets
In this paper, we present an integrated structural and behavioral model of
Reo connectors and Petri nets, allowing a direct comparison of the two
concurrency models. For this purpose, we introduce a notion of connectors which
consist of a number of interconnected, user-defined primitives with fixed
behavior. While the structure of connectors resembles hypergraphs, their
semantics is given in terms of so-called port automata. We define both models
in a categorical setting where composition operations can be elegantly defined
and integrated. Specifically, we formalize structural gluings of connectors as
pushouts, and joins of port automata as pullbacks. We then define a semantical
functor from the connector to the port automata category which preserves this
composition. We further show how to encode Reo connectors and Petri nets into
this model and indicate applications to dynamic reconfigurations modeled using
double pushout graph transformation
Complex itinerant ferromagnetism in noncentrosymmetric Cr11Ge19
The noncentrosymmetric ferromagnet Cr11Ge19 has been investigated by
electrical transport, AC and DC magnetization, heat capacity, x-ray
diffraction, resonant ultrasound spectroscopy, and first principles electronic
structure calculations. Complex itinerant ferromagnetism in this material is
indicated by nonlinearity in conventional Arrott plots, unusual behavior of AC
susceptibility, and a weak heat capacity anomaly near the Curie temperature (88
K). The inclusion of spin wave excitations was found to be important in
modeling the low temperature heat capacity. The temperature dependence of the
elastic moduli and lattice constants, including negative thermal expansion
along the c axis at low temperatures, indicate strong magneto-elastic coupling
in this system. Calculations show strong evidence for itinerant ferromagnetism
and suggest a noncollinear ground state may be expected
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