Black hole solutions of N=2, d=4 supergravity with a quantum correction, in the H-FGK formalism

We apply the H-FGK formalism to the study of some properties of the general class of black holes in N=2 supergravity in four dimensions that correspond to the harmonic and hyperbolic ansatze and obtain explicit extremal and non-extremal solutions for the t^3 model with and without a quantum correction. Not all solutions of the corrected model (quantum black holes), including in particular a solution with a single q_1 charge, have a regular classical limit.Comment: Latex2e file +Bibtex file, 35 pages, no figure

Non-supersymmetric black-hole solutions in N=2,D=4 supergravity

Esta tesis de doctorado se dedica al estudio de los agujeros negros de supergravedad N=2 en cuatro dimensiones. Se concentra principalmente en el ánalisis de soluciones no supersimétricas, extremas y no extremas, a un solo centro o a multi-centro. Se han utilizado y profundizado nociones importantes como el formalismo de primer orden y el formalismo H-FGK. Se han encontrado nuevas soluciones de agujero negro y nuevas simetrías entre las variables del sistemas.This doctoral thesis contains a thorough study of the non-supersymmetric branch of supergravity black holes arising in four-dimensional N=2 theories interacting with abelian vector and scalar fields. It addresses the problem of describing supersymmetric and non supersymmetric, both extremal (also multicentre) and non extremal solutions with a similar formalism, based on first order dynamical equations driven by a superpotential. The new perspective provided by the so called H-FGK formalism and its outcomes are extensively discussed and proposed as a unifying framework

As motivações para o rejuvenescimento de software : uma abordagem em grounded theory acompanhada de NLP

Trabalho de conclusão de curso (graduação) — Universidade de Brasília, Instituto de Ciências Exatas, Departamento de Ciência da Computação, 2021.Os Engenheiros de Software estão constantemente buscando melhorar seus processos de desenvolvimento de software. Uma parte significativa da melhora do processo de desen volvimento está contida nas novas formas que vão surgindo de desenvolver o software, por meio das novas funcionalidades que passam a existir quando as linguagens de progra mação evoluem. Esse processo de evolução, entretanto, não está ligado apenas a questões técnicas e computacionais, mas também a questões sociais e humanas. Na última década, vem ocorrendo um aumento substancial de pesquisas na área de software que exploram as questões humanas, sociais e mercadológicas do software, sendo que em muitos casos é utilizada a metodologia Grounded Theory para tal. No presente artigo, utilizamos a metodologia Grounded Theory para evidenciar qual a relação entre a evolução do software e a evolução da linguagem utilizada para o desen volvimento deste software. Propomos também uma adaptação no processo da metodologia Grounded Theory, acrescentando uma etapa quantitativa em seu processo com o uso de Processamento de Linguagem Natural, com o objetivo de encontrar melhores respostas para a pergunta de pesquisa apresentada. Utilizamos a Grounded Theory como um método quanti-qualitativo para estudar 23 entrevistas com desenvolvedores experientes e de experiências diversas para compreender melhor as motivações por trás da evolução do software. Como resultados, apresentamos (a) uma amostra dos resultados alcançados pela aplicação parcial da metodologia de Grounded Theory no contexto da evolução do software; (b) uma maneira de aplicar o processamento de linguagem natural no contexto de análises qualitativas

On anharmonic stabilisation equations for black holes

Abstract: We investigate the stabilisation equations for sufficiently general, yet regular, extremal (supersymmetric and non-supersymmetric) and non-extremal black holes in fourdimensional N = 2 supergravity using both the H-FGK approach and a generalisation of Denef's formalism. By an explicit calculation we demonstrate that the equations necessarily contain an anharmonic part, even in the static, spherically symmetric and asymptotically flat case

Antidiabetic thiazolidinediones induce ductal differentiation but not apoptosis in pancreatic cancer cells

AIM: Thiazolidinediones (TZD) are a new class of oral antidiabetic drugs that have been shown to inhibit growth of same epithelial cancer cells. Although TZD were found to be ligands for peroxisome proliferator-activated receptor gamma (PPARgamma), the mechanism by which TZD exert their anticancer effect is presently unclear. In this study, we analyzed the mechanism by which TZD inhibit growth of human pancreatic carcinoma cell lines in order to evaluate the potential therapeutic use of these drugs in pancreatic adenocarcinoma. METHODS: The effects of TZD in pancreatic cancer cells were assessed in anchorage-independent growth assay. Expression of PPARgamma was measured by reverse-transcription polymerase chain reaction and confirmed by Western blot analysis. PPARgamma activity was evaluated by transient reporter gene assay. Flow cytometry and DNA fragmentation assay were used to determine the effect of TZD on cell cycle progression and apoptosis respectively. The effect of TZD on ductal differentiation markers was performed by Western blot. RESULTS: Exposure to TZD inhibited colony formation in a PPARgamma-dependent manner. Growth inhibition was linked to G1 phase cell cycle arrest through induction of the ductal differentiation program without any increase of the apoptotic rate. CONCLUSION: TZD treatment in pancr

Volatilidade, magnitude dos proventos e a sinalização na política de distribuição de lucros

Este trabalho procurou testar a teoria da sinalização por meio das notícias veiculadas aos investidores que se referem ao anúncio da distribuição de proventos de 1998 a 2006, para as ações integrantes da carteira teórica do Ibovespa de janeiro a abril de 2006. Para a realização deste artigo, foram efetuados cálculos para verificar a presença de retornos anormais nas datas de anúncio da distribuição de juros sobre capital próprio, dividendos e pagamento simultâneo. Adicionalmente, foram realizados testes nos dias ao redor da data de anúncio, numa janela de 11 dias, incluindo a data da divulgação do pagamento dos proventos na busca de vazamento de informações e para verificar a possibilidade de arbitragem na janela em estudo. Os testes realizados consideraram a presença de retornos anormais e acumulados quando o mercado estava operando em níveis diferentes de volatilidade do mercado e de magnitude do provento anunciado, procurando verificar se os investidores interpretam e penalizam o pagamento de dividendos de maneira simétrica com relação às variações de volatilidade do mercado e de magnitude do provento anunciado. Os resultados evidenciaram a presença de retornos anormais significativos

Doubly resonant photoacoustic spectroscopy: ultra-high sensitivity meets ultra-wide dynamic range

Photoacoustic spectroscopy (PAS) based gas sensors with high sensitivity, wide dynamic range, low cost, and small footprint are desirable across a broad range of applications in energy, environment, safety, and public health. However, most works have focused on either acoustic resonator to enhance acoustic wave or optical resonator to enhance optical wave. Herein, we develop a gas sensor based on doubly resonant PAS in which the acoustic and optical waves are simultaneously enhanced using combined optical and acoustic resonators in a centimeter-long configuration. Not only the lower detection limit is enhanced by the double standing waves, but also the upper detection limit is expanded due to the short resonators. As an example, we developed a sensor by detecting acetylene (C2H2), achieving a noise equivalent absorption of 5.7*10-13 cm-1 and a dynamic range of eight orders. Compared to the state-of-the-art PAS gas sensors, the developed sensor increases the sensitivity by two orders of magnitude and extends the dynamic range by three orders of magnitude. Besides, a laser-cavity-molecule locking strategy is proposed to provide additional flexibility of fast gas detection

Virtual reality for the assessment of everyday cognitive functions in older adults: an evaluation of the virtual reality action test and two interaction devices in a 91-year-old woman

Performance-based functional tests for the evaluation of daily living activities demonstrate strong psychometric properties and solve many of the limitations associated with self- and informant-report questionnaires. Virtual reality (VR) technology, which has gained interest as an effective medium for administering interventions in the context of healthcare, has the potential to minimize the time-demands associated with the administration and scoring of performance-based assessments. To date, efforts to develop VR systems for assessment of everyday function in older adults generally have relied on non-immersive systems. The aim of the present study was to evaluate the feasibility of an immersive VR environment for the assessment of everyday function in older adults. We present a detailed case report of an elderly woman who performed an everyday activity in an immersive VR context (Virtual Reality Action Test) with two different types of interaction devices (controller vs. sensor). VR performance was compared to performance of the same task with real objects outside of the VR system (Real Action Test). Comparisons were made on several dimensions, including (1) quality of task performance (e.g., order of task steps, errors, use and speed of hand movements); (2) subjective impression (e.g., attitudes), and (3) physiological markers of stress. Subjective impressions of performance with the different controllers also were compared for presence, cybersickness, and usability. Results showed that the participant was capable of using controllers and sensors to manipulate objects in a purposeful and goal-directed manner in the immersive VR paradigm. She performed the everyday task similarly across all conditions. She reported no cybersickness and even indicated that interactions in the VR environment were pleasant and relaxing. Thus, immersive VR is a feasible approach for function assessment even with older adults who might have very limited computer experience, no prior VR exposure, average educational experiences, and mild cognitive difficulties. Because of inherent limitations of single case reports (e.g., unknown generalizability, potential practice effects, etc.), group studies are needed to establish the full psychometric properties of the Virtual Reality Action Test