3,111 research outputs found

    Presencia de Bryopsida fértil en los niveles Westfalianos del subgrup Itararé, Cuenca de Paraná, Brasil

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    The bryophyte fossils are rare, mainly in Paleozoic sedimentary rocks in spite of being present since the Silurian Period. In the Division Bryophyta, the fossils that belong to the Class Bryopsida are recognized since the Carboniferous, but they are extremely scarce. They are plentiful only in Permian sediments, in the Petchora, Kuznetsk and Russian Platform basins, also in Antarctica, Karoo basin (the last in South Africa) and India. Identified at the genus Dwykea, gametophyte specimens bearing pleurocarpous sporophyte were recovered from the lowermost levels of Itararé Subgroup, near Campinas city, S. Paulo State. These fossils correspond to the first register of bryophyte female gametophyte for the Carboniferous Period. The microflora in association with these fossils allow correlations of these levels to the Palynozone Ahrensisporites cristatus of Westphalian age. Related to proglacial sediments, they may correspond to a tundra vegetation covering the Northeastern border of Paraná Basin, during the Westphalian.Los fósiles atribuidos a briófitos son escasos, principalmente en rocas paleozoicas a pesar de ser registrados desde el Silúrico. Para la División Bryophyta, los fósiles correspondientes a la Clase Bryopsida comienzan a ser encontrados a partir del Carbonífero, aunque son bastante escasos. Registros más abundantes son conocidos para el Pérmico en rocas de las cuencas de Petchora, Kuznetsk y en la Plataforma Rusa, así como en la Antártica, en la Cuenca del Karoo (África del Sur) e India. Especímenes de gametófitos con esporofitos pleurocárpicos del género Dwykea fueron colectados en los niveles inferiores del Subgrupo Itararé, próximos a la ciudad de Campinas, Estado de S. Paulo. Estos fósiles corresponden al primer registro para el periodo Carbonífero de gametofitos femeninos fértiles. La microflora asociada a los fósiles de Dwykea permite establecer correlaciones con la Palinozona Ahrensisporites cristatus de edad westfaliana. Además los niveles donde fueron colectados los ejemplares de Dwykea corresponden a sedimentos proglaciales, que son interpretados como una vegetación de tundra que habitaba en el margen noreste de la Cuenca del Paraná, durante el Westfaliano

    Normal Stress Distribution of Rough Surfaces in Contact

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    We study numerically the stress distribution on the interface between two thick elastic media bounded by interfaces that include spatially correlated asperities. The interface roughness is described using the self-affine topography that is observed over a very wide range of scales from fractures to faults. We analyse the correlation properties of the normal stress distribution when the rough surfaces have been brought into full contact. The self affinity of the rough surfaces is described by a Hurst exponent H. We find that the normal stress field is also self affine, but with a Hurst exponent H-1. Fluctations of the normal stress are shown to be important, especially at local scales with anti-persistent correlations.Comment: 11 pages LaTeX, 4 Postscript figures, submitted to Geophysical Research Letter

    The No-defect Conjecture: Cosmological Implications

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    When the topology of the universe is non trivial, it has been shown that there are constraints on the network of domain walls, cosmic strings and monopoles. I generalize these results to textures and study the cosmological implications of such constraints. I conclude that a large class of multi-connected universes with topological defects accounting for structure formation are ruled out by observation of the cosmic microwave background.Comment: 4 pages, 1 figure, accepted for publication as a brief report in Phys. Rev.

    Cosmic microwave background anisotropies in multi-connected flat spaces

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    This article investigates the signature of the seventeen multi-connected flat spaces in cosmic microwave background (CMB) maps. For each such space it recalls a fundamental domain and a set of generating matrices, and then goes on to find an orthonormal basis for the set of eigenmodes of the Laplace operator on that space. The basis eigenmodes are expressed as linear combinations of eigenmodes of the simply connected Euclidean space. A preceding work, which provides a general method for implementing multi-connected topologies in standard CMB codes, is then applied to simulate CMB maps and angular power spectra for each space. Unlike in the 3-torus, the results in most multi-connected flat spaces depend on the location of the observer. This effect is discussed in detail. In particular, it is shown that the correlated circles on a CMB map are generically not back-to-back, so that negative search of back-to-back circles in the WMAP data does not exclude a vast majority of flat or nearly flat topologies.Comment: 33 pages, 19 figures, 1 table. Submitted to PR

    Use of Wild Type or Recombinant Lactic Acid Bacteria as an Alternative Treatment for Gastrointestinal Inflammatory Diseases: A Focus on Inflammatory Bowel Diseases and Mucositis

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    The human gastrointestinal tract (GIT) is highly colonized by bacterial communities, which live in a symbiotic relationship with the host in normal conditions. It has been shown that a dysfunctional interaction between the intestinal microbiota and the host immune system, known as dysbiosis, is a very important factor responsible for the development of different inflammatory conditions of the GIT, such as the idiopathic inflammatory bowel diseases (IBD), a complex and multifactorial disorder of the GIT. Dysbiosis has also been implicated in the pathogenesis of other GIT inflammatory diseases such as mucositis usually caused as an adverse effect of chemotherapy. As both diseases have become a great clinical problem, many research groups have been focusing on developing new strategies for the treatment of IBD and mucositis. In this review, we show that lactic acid bacteria (LAB) have been capable in preventing and treating both disorders in animal models, suggesting they may be ready for clinical trials. In addition, we present the most current studies on the use of wild type or genetically engineered LAB strains designed to express anti-inflammatory proteins as a promising strategy in the treatment of IBD and mucositis

    The 20-minute whole blood clotting test (20WBCT) for snakebite coagulopathy—A systematic review and meta-analysis of diagnostic test accuracy

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    Background The 20-minute whole blood clotting test (20WBCT) has been used to detect coagulopathy following snakebite for almost 50 years. A systematic review and meta-analysis of the 20WBCT was conducted to evaluate the accuracy of the 20WBCT to detect coagulopathy, indicative of systemic envenoming. Methods and findings Databases were searched from inception up to 09/12/2020 to identify studies that compared the 20WBCT and INR/fibrinogen on five or more subjects. Data was extracted from full-text articles by two reviewers using a predetermined form. Authors of 29 studies that lacked sufficient details in the manuscript were contacted and included if data meeting the inclusion criteria were provided. Included studies were evaluated for bias using a tailored QUADAS-2 checklist. The study protocol was prospectively registered on PROSPERO database (CRD42020168953). The searches identified 3,599 studies, 15 met the inclusion criteria and 12 were included in the meta-analysis. Data was reported from 6 countries and included a total of 2,270 patients. The aggregate weighted sensitivity of the 20WBCT at detecting INR >1.4 was 0.84 (CI 0.61 to 0.94), the specificity was 0.91 (0.76 to 0.97) and the SROC AUC was 0.94 (CI 0.91 to 0.96). The aggregate weighted sensitivity of the 20WBCT at detecting fibrinogen <100 mg/dL was 0.72 (CI 0.58 to 0.83), the specificity was 0.94 (CI 0.88 to 0.98) and the SROC AUC was 0.93 (0.91 to 0.95). Both analyses that used INR and fibrinogen as the reference test displayed considerable heterogeneity. Conclusions In the absence of laboratory clotting assays, the 20WBCT remains a highly specific and fairly sensitive bedside test at detecting coagulopathy following snakebite. However, clinicians should be aware of the importance of operator training, standardized equipment and the lower sensitivity of the 20WBCT at detecting mild coagulopathy and resolution of coagulopathy following antivenom

    Kinin B(1) receptor deficiency leads to leptin hypersensitivity and resistance to obesity

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    OBJECTIVE-Kinins mediate pathophysiological processes related to hypertension, pain, and inflammation through the activation of two G-protein-coupled receptors, named B(1) and B(2). Although these peptides have been related to glucose homeostasis, their effects on energy balance are still unknown.RESEARCH DESIGN and METHODS-Using genetic and pharmacological strategies to abrogate the kinin B(1) receptor in different animal models of obesity, here we present evidence of a novel role for kinins in the regulation of satiety and adiposity.RESULTS-Kinin B(1) receptor deficiency in mice (B(1)(-/-)) resulted in less fat content, hypoleptinemia, increased leptin sensitivity, and robust protection against high-fat diet-induced weight gain. Under high-fat diet, B(1)(-/-) also exhibited reduced food intake, improved lipid oxidation, and increased energy expenditure. Surprisingly, B(1) receptor deficiency was not able to decrease food intake and adiposity in obese mice lacking leptin (ob/ob-B(1)(-/-)). However, ob/ob-B(1)(-/-) mice were more responsive to the effects of exogenous leptin on body weight and food intake, suggesting that B(1) receptors may be dependent on leptin to display their metabolic roles. Finally, inhibition of weight gain and food intake by B(1) receptor ablation was pharmacologically confirmed by long-term administration of the kinin B(1) receptor antagonist SSR240612 to mice under high-fat diet.CONCLUSIONS-Our data suggest that kinin B(1) receptors participate in the regulation of the energy balance via a mechanism that could involve the modulation of leptin sensitivity.Universidade Federal de São Paulo, Dept Biophys, BR-04023062 São Paulo, BrazilUniv Mogi das Cruzes, Mogi Das Cruzes, BrazilUniversidade Federal de São Paulo, Dept Physiol, BR-04023062 São Paulo, BrazilSanofi Aventis, Montpellier, FranceUniversidade Federal de São Paulo, Dept Med, BR-04023062 São Paulo, BrazilInst Natl Sante & Rech Med, Dept Renal & Cardiac Remodeling, U858 I2MR, Toulouse, FranceUniv Toulouse 3, Inst Med Mol Rangueil, F-31062 Toulouse, FranceInst Natl Rech Agron AgroParisTech, UMR914 Nutr Physiol & Ingest Behav, Paris, FranceMax Delbruck Ctr Mol Med, Berlin, GermanyUniversidade Federal de São Paulo, Dept Biophys, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Physiol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Med, BR-04023062 São Paulo, BrazilWeb of Scienc

    ENDOVASCULAR ANEURYSM REPAIR IN WIDE INFRARENAL NECKS - INCREASED RISK OF COMPLICATIONS?

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    EVAR has become the predominant repair technique for abdominal aortic aneurysm. Long-term clinical success relies greatly upon a long-lasting proximal seal. EVAR has achieved good outcomes on the short-term in patients with hostile neck features such as large proximal necks. However, the long-term outcomes in these patients is greatly unknown. In this article, the authors perform a literature review in order to assess the clinical impact of wide proximal neck on mid to long-term outcomes following EVAR
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