Exact solutions for supersymmetric stationary black hole composites

Four dimensional N=2 supergravity has regular, stationary, asymptotically flat BPS solutions with intrinsic angular momentum, describing bound states of separate extremal black holes with mutually nonlocal charges. Though the existence and some properties of these solutions were established some time ago, fully explicit analytic solutions were lacking thus far. In this note, we fill this gap. We show in general that explicit solutions can be constructed whenever an explicit formula is known in the theory at hand for the Bekenstein-Hawking entropy of a single black hole as a function of its charges, and illustrate this with some simple examples. We also give an example of moduli-dependent black hole entropy.Comment: 13 pages, 1 figur

Heterotic Strings on Generalized Calabi-Yau Manifolds and Kaehler Moduli Stabilization

Compactifications of heterotic string theory on Generalized Calabi-Yau manifolds have been expected to give the same type of flexibility that type IIB compactifications on Calabi-Yau orientifolds have. In this note we generalize the work done on half-flat manifolds by other authors, to show how flux quantization occurs in the general case, by starting with a basis of harmonic forms and then extending it. However it turns out that only the axions associated with the non-harmonic directions in the space of Kaehler moduli, can be stabilized by the geometric (torsion) terms. Also we argue that there are no supersymmetric extrema of the potential when the second (and fourth) cohomology groups on the manifold are non-trivial. We suggest that threshold corrections to the classical gauge coupling function could solve these problems.Comment: 9 page

Comprehensive Review of Heat Transfer Correlations of Supercritical CO2 in Straight Tubes Near the Critical Point: A Historical Perspective

An exhaustive review was undertaken to assemble all available correlations for supercritical CO2 in straight, round tubes of any orientation with special attention paid to how the wildly varying fluid properties near the critical point are handled. The assemblage of correlations, and subsequent discussion, is presented from a historical perspective, starting from pioneering work on the topic in the 1950s to the modern day. Despite the growing sophistication of sCO2 heat transfer correlations, modern correlations are still only generally applicable over a relatively small range of operating conditions, and there has not been a substantial increase in predictive capabilities. Recently, researchers have turned to machine learning as a tool for next-generation heat transfer prediction. An overview of the state-of-the-art of predicting sCO2 heat transfer using machine learning methods, such as artificial neural networks, is also presented

Propagation of tau and α-synuclein in the brain: therapeutic potential of the glymphatic system

Many neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, are characterised by the accumulation of misfolded protein deposits in the brain, leading to a progressive destabilisation of the neuronal network and neuronal death. Among the proteins that can abnormally accumulate are tau and α-synuclein, which can propagate in a prion-like manner and which upon aggregation, represent the most common intracellular proteinaceous lesions associated with neurodegeneration. For years it was thought that these intracellular proteins and their accumulation had no immediate relationship with extracellular homeostasis pathways such as the glymphatic clearance system; however, mounting evidence has now suggested that this is not the case. The involvement of the glymphatic system in neurodegenerative disease is yet to be fully defined; however, it is becoming increasingly clear that this pathway contributes to parenchymal solute clearance. Importantly, recent data show that proteins prone to intracellular accumulation are subject to glymphatic clearance, suggesting that this system plays a key role in many neurological disorders. In this review, we provide a background on the biology of tau and α-synuclein and discuss the latest findings on the cell-to-cell propagation mechanisms of these proteins. Importantly, we discuss recent data demonstrating that manipulation of the glymphatic system may have the potential to alleviate and reduce pathogenic accumulation of propagation-prone intracellular cytotoxic proteins. Furthermore, we will allude to the latest potential therapeutic opportunities targeting the glymphatic system that might have an impact as disease modifiers in neurodegenerative diseases

Compostagem de resíduos alimentares: uma abordagem em um ambiente escolar

Research that addresses ecological alternatives to waste generated by society must be supported today. Composting is one of these alternatives, but to put it into practice it is necessary to modify some chronic concepts that are intrinsically linked to society. The school has a decisive role inherent to the change of social concepts, if the composting is carried out in it the social impact is much more intense. A school can be a very propitious place to practice domestic composting, since it offers several inputs that can be used for this purpose, and being a public school it has in its school meals a constant source of composting raw material. In addition to producing natural fertilizer in the school itself, the school community has a great opportunity to address the cross-cutting themes of NCPs / 1997. In addition to these benefits, if the school has a community garden in its premises, composting can be used to produce fertilizer and consequently be used in this garden, which later provides ingredients for the preparation of the meal, and the latter provides inputs to domestic composting; Which would generate a sustainable cycle within the school itself. Within this context, some public schools in the municipality of Cabo de Santo Agostinho were interviewed in order to verify which facilitators were involved, what difficulties could be encountered and what paths were to be taken to achieve the operation of an environmental project such as this within of a School Unit and with the participation of all those who make up these learning spaces.Pesquisas que abordem alternativas ecológicas para os resíduos gerados pela sociedade devem ser respaldadas nos dias atuais. A compostagem é uma dessas alternativas, mas para colocá-la em prática é preciso modificar alguns conceitos crônicos que estão ligados intrinsicamente à sociedade. A escola tem um papel decisivo inerente à mudança de conceitos sociais, se a compostagem for realizada nela o impacto social é bem mais intenso. Uma escola pode ser um local bastante propício à prática da compostagem doméstica, pois ela oferece diversos insumos que podem ser utilizados para esta finalidade, e sendo uma escola pública ela tem na sua merenda escolar, uma fonte constante de matéria-prima para a compostagem. Além de produzir o adubo natural na própria escola, a comunidade escolar tem uma grande oportunidade de abordar os temas transversais dos PCNs/1997. Além desses benefícios, se a escola possuir em suas dependências uma horta comunitária, a compostagem pode servir para a produção de adubo e consequentemente ser destinado a esta horta, que posteriormente fornece ingredientes ao preparo da merenda, e que esta última fornece insumos à compostagem doméstica; o que geraria assim um ciclo sustentável dentro da própria escola. Dentro deste contexto, foram entrevistadas algumas escolas públicas do município do Cabo de Santo Agostinho a fim de verificar quais os agentes facilitadores, quais as dificuldades que poderiam ser encontradas e quais os caminhos a serem percorridos para alcançar o funcionamento de um projeto ambiental como este dentro de uma Unidade Escolar e com a participação de todos aqueles que compõem estes espaços de aprendizagem

Análise de imagens de séries temporais NDVI do sensor MODIS no Parque Nacional da Serra da Canastra

Monografia (graduação)—Universidade de Brasília, Instituto de Ciências Humanas, Departamento de Geografia, 2014.O presente estudo visa à delimitação das fitofisionomias vegetais presentes no Parque nacional da Serra da Canastra, o parque é uma unidade de conservação federal de grande importância para a conservação de nascentes de importantes rios brasileiros e proteção da grande biodiversidade encontrada nos arredores. Para tal procedimento as ferramentas de sensoriamento remoto foram escolhidas por serem as que melhor podem ajudar no processo. As imagens do sensor MODIS (Moderate Resolution Imaging Spectroradiometer) foram utilizadas e passaram pela geração do índice de NDVI (Normalized Difference Vegetation Index – Índice de Vegetação da Diferença Normalizada), após a realização de um processo de filtragem e classificação os resultados serão avaliados, o período escolhido foi entre os anos de 2000 a 2012. ______________________________________________________________________________ ABSTRACTThis research work is intended to delimit different vegetation types found inside the Serra da Canastra National Park. The park is a federal protected area where there is a need to conserve headwaters from important Brazilian rivers, and to protect biodiversity found around its area. In order to accomplish this procedure, remote sensing tools were chosen because it was thought to be the best way to do it. MODIS Images (Moderate Resolution Imaging Spectroradiometer) were used and processed on NDVI (Normalized Difference Vegetation Index), after a filtering and classifying process. The results will be evaluated. The period chosen goes from 2000 to 2012

Análise da gestão do turismo do circuito da natureza em Almirante Tamandaré - PR.

Orientador : Luciane de Fátima NériMonografia (especialização) - Universidade Federal do Paraná, Setor de Ciencias Humanas Letras e Artes, Curso de Especializaçao em Psicologia do Trabalh

Nonlinear stabilitty for steady vortex pairs

In this article, we prove nonlinear orbital stability for steadily translating vortex pairs, a family of nonlinear waves that are exact solutions of the incompressible, two-dimensional Euler equations. We use an adaptation of Kelvin's variational principle, maximizing kinetic energy penalised by a multiple of momentum among mirror-symmetric isovortical rearrangements. This formulation has the advantage that the functional to be maximized and the constraint set are both invariant under the flow of the time-dependent Euler equations, and this observation is used strongly in the analysis. Previous work on existence yields a wide class of examples to which our result applies.Comment: 25 page