3,651 research outputs found
Topological Field Theories and Duality
Get PDFTopologically non trivial effects appearing in the discussion of duality
transformations in higher genus manifolds are discussed in a simple example,
and their relation with the properties of Topological Field Theories is
established.Comment: 7 pages, Late
On non-abelian T-dual geometries with Ramond fluxes
Full text linkWe show how to implement T-duality along non-abelian isometries in
backgrounds with non-vanishing Ramond fields. When the dimension of the
isometry group is odd (even) the duality swaps (preserves) the chirality of the
theory. In certain cases a non-abelian duality can result in a massive type-IIA
background. We provide two examples by dualising SU(2) isometry subgroups in
and . The resultant dual
geometries inherit the original AdS factors but have transverse spaces with
reduced isometry and preserve only half of the original supersymmetry. The
non-abelian dual of has an M-theory lift which is related to
the gravity duals of N=2 superconformal theories. We comment on a possible
interpretation of this as a high spin limit.Comment: 33 page
T-Duality and Penrose limits of spatially homogeneous and inhomogeneous cosmologies
Get PDFPenrose limits of inhomogeneous cosmologies admitting two abelian Killing
vectors and their abelian T-duals are found in general. The wave profiles of
the resulting plane waves are given for particular solutions. Abelian and
non-abelian T-duality are used as solution generating techniques. Furthermore,
it is found that unlike in the case of abelian T-duality, non-abelian T-duality
and taking the Penrose limit are not commutative procedures.Comment: 16 pages, 4 figures. Discussion on non-abelian T-duality expande
Blood transfusion in preterm infants improves intestinal tissue oxygenation without alteration in blood flow
Get PDFBACKGROUND AND OBJECTIVE: The objective of the study was to investigate the splanchnic blood flow velocity and oximetry response to blood transfusion in preterm infants according to postnatal age.
MATERIALS AND METHODS: Preterm infants receiving blood transfusion were recruited to three groups: 1–7 (group 1; n = 20), 8–28 (group 2; n = 21) and ≥29 days of life (group 3; n = 18). Superior mesenteric artery (SMA) peak systolic (PSV) and diastolic velocities were measured 30–60 min pre- and post-transfusion using Doppler ultrasound scan. Splanchnic tissue haemoglobin index (sTHI), tissue oxygenation index (sTOI) and fractional tissue oxygen extraction (sFTOE) were measured from 15–20 min before to post-transfusion using near-infrared spectroscopy.
RESULTS: The mean pretransfusion Hb in group 1, 2 and 3 was 11, 10 and 9 g/dl, respectively. The mean (SD) pretransfusion SMA PSV in group 1, 2 and 3 was 0·63 (0·32), 0·81 (0·33) and 0·97 (0·40) m/s, respectively, and this did not change significantly following transfusion. The mean (SD) pretransfusion sTOI in group 1, 2 and 3 was 36·7 (19·3), 44·6 (10·4) and 41·3 (10·4)%, respectively. The sTHI and sTOI increased (P < 0·01), and sFTOE decreased (P < 0·01) following transfusion in all groups. On multivariate analysis, changes in SMA PSV and sTOI following blood transfusion were not associated with PDA, feeding, pretransfusion Hb and mean blood pressure.
CONCLUSION: Pretransfusion baseline splanchnic tissue oximetry and blood flow velocity varied with postnatal age. Blood transfusion improved intestinal tissue oxygenation without altering mesenteric blood flow velocity irrespective of postnatal ages
Singular shell embedded into a cosmological model
Full text linkWe generalize Israel's formalism to cover singular shells embedded in a
non-vacuum Universe. That is, we deduce the relativistic equation of motion for
a thin shell embedded in a Schwarzschild/Friedmann-Lemaitre-Robertson-Walker
spacetime. Also, we review the embedding of a Schwarzschild mass into a
cosmological model using "curvature" coordinates and give solutions with
(Sch/FLRW) and without the embedded mass (FLRW).Comment: 25 pages, 2 figure
DO WOMEN MANAGE SMALLER FUNDS?
Full text linkBased on a sample of 467 asset managers from four countries we robustly find that women manage smaller funds than men, despite tough competition in this industry. Interestingly, the gender gap exists only for managers of smaller funds, i.e. at the lower end of the hierarchy, as quantile regressions show. This is inconsistent with the glass ceiling hypothesis. Going further, this gender gap is limited to large firms. Explanations may refer to large firms using market power in the area of smaller funds or to visibility among top asset managers protecting against unequal treatment of the sexes
Auto Cars
Get PDFSomos um grupo de quatro estudantes: Gustavo Henrique Roepke, Camila Hermann Tomio, Camilla Rosa e Vinícius Friedrich Blau. Estudamos no Instituto Federal Catarinense, campus Blumenau, cursamos informática. Esse projeto teve início na matéria desenvolvimento de projeto com o professor Luiz Ricardo Uriarte e Ricardo de La Rocha Ladeira. Muitas pessoas querem achar e comparar diferentes tipos de carros, porém não possuem conhecimento sobre esse ramo e querem algo mais prático, rápido e que não ocupe muito seu tempo. Nosso projeto ajudará com esses pequenos problemas sendo muito mais prático de utilizar o site e contendo especificações deles como o motor, tanque, preço, modelo, etc. E um breve resumo sobre ele. Nossos métodos saíram do papel recentemente, começamos a programar usando o Visual Studio Code, usamos o uizard.io para fazer o design do site. Todas as imagens utilizadas possuem direitos autorais livres. Discutimos em roda de conversas sobre como iríamos fazer algo fácil de visualizar e de fácil entendimento para os usuários do site. Essa ideia surgiu após uma pesquisa de um integrante do grupo onde ele teve dificuldade em achar as informações que precisava, tivemos a ideia de fazer esse projeto, assim iniciamos uma pesquisa para iniciar esse projeto, conclusão queremos fazer algo prático e sistemático para atender o máximo de pessoas possível, assim resolvendo uma possível frustração de alguém. Nosso site exige um cadastramento de usuário para login, no cadastro pedirá nome, senha, email e nome de usuário. Nosso banco de dados será criptografado com hash, ou seja, sua conta estará quase totalmente protegida por ele. O site contará com 5 modelos de carros, entre eles: Esportivos, Off-road, Vans, Populares e Econômicos. Cada um desses modelos contará com 3 tipos de carros diferentes, com suas devidas explicações (citadas acima). Dentro deste site, os usuários poderão favoritar os carros selecionados pelos mesmos, e é claro, terá uma aba específica dentro do site para os carros favoritos
Social mobility from a comparative perspective between Europe and Latin America
Get PDFProduction of INCASI Project H2020-MSCA-RISE-2015 GA 691004This chapter presents a review of the analysis of social mobility in the international sphere (Europe and Latin America), with a particular focus on the partner countries of the INCASI network. To date, few studies have linked nations whose economic and social aspects are so dissimilar. As is usual in the specialized literature, the relationship between social origin and class destination is addressed. This is done by noting the comparisons made across the geographical areas. We review the analyses that have been made of the evolution of social fluidity as well as the distance between social classes within each country and the comparisons made between them. We compare the main theories that have inspired the study of social mobility to date: modernization theory, which predicts an increase in relative mobility rates, and invariance theory, which postulates the constancy of social fluidity. Special attention is devoted to the role played by the family, the state and the market in late industrialized countries. We study the difficulties for social change, i.e. upward mobility from one class to another, as well as the likelihood of reproduction in comparative terms. To do so, we link these mechanisms with the AMOSIT model. The advances in methodology, techniques, theory and data processing are highlighted
Disproportionate Hyperproinsulinemia, \u3b2-Cell Restricted Prohormone Convertase 2 Deficiency, and Cell Cycle Inhibitors Expression by Human Islets Transplanted Into Athymic Nude Mice: Insights Into Nonimmune-Mediated Mechanisms of Delayed Islet Graft Failure
Get PDFTo learn more about nonimmune-mediated islet graft failure, we transplanted different preparations (preps) of isolated human islets under the kidney capsule of streptozotocin (STZ)-diabetic nude mice. One month after the implantation of 1,000 or 2,000 islets, grafts were harvested for morphological, immunohistochemical, and ultrastructural analysis. Only a single islet prep cured the diabetes out of all the recipients, while the remaining preps showed only partial function after the implantation of 2,000 islets. Transplanted mice showed high circulating proinsulin levels but, with the exclusion of those bearing curative grafts, relatively low mature insulin levels. Engrafted beta-cells showed positive carboxypeptidase E (CPE) and prohormone convertase 1 (PC1) staining, while prohormone convertase 2 (PC2) was undetectable. In contrast, PC2 was abundantly expressed by engrafted alpha-cells. Moreover, engrafted beta-cells did not show evidence of replication, and preapoptotic beta-cells, with intra- and extracellular amyloid deposition, were detected with electron microscopy. Cell cycle inhibitors p16(INK4), p21(WAF1), and p27(Kip1) were abundantly expressed in the islet grafts and showed a predominant nuclear localization. In conclusion, diabetic nude mice transplanted with human islets showed disproportionate hyperproinsulinemia and graft evidence of beta-cell restricted PC2 depletion, amyloid deposition and beta-cell death, and lack of beta-cell replication with nuclear translocation of p27(Kip1) and p21(WAF1) that together may contribute to delayed graft failur
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