239 research outputs found

    Willmore surfaces and Hopf tori in homogeneous 3-manifolds

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    Some classification results for closed surfaces in Berger spheres are presented. On the one hand, a Willmore functional for isometrically immersed surfaces into an homogeneous space E3(Îș,τ) with isometry group of dimension 4 is defined and its first variational formula is computed. Then, we characterize Clifford and Hopf tori as the only Willmore surfaces satisfying a sharp Simons-type integral inequality. On the other hand, we also obtain some integral inequalities for closed surfaces with constant extrinsic curvature in E3(Îș,τ), becoming equalities if and only if the surface is a Hopf torus in a Berger sphere

    Willmore surfaces and Hopf tori in homogeneous 3-manifolds

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    Some classification results for closed surfaces in Berger spheres are presented. On the one hand, a Willmore functional for isometrically immersed surfaces into an homogeneous space E3(Îș,τ)\mathbb{E}^{3}(\kappa,\tau) with isometry group of dimension 44 is defined and its first variational formula is computed. Then, we characterize Clifford and Hopf tori as the only Willmore surfaces satifying a sharp Simons-type integral inequality. On the other hand, we also obtain some integral inequalities for closed surfaces with constant extrinsic curvature in E3(Îș,τ)\mathbb{E}^3(\kappa,\tau), becoming equalities if and only if the surface is a Hopf torus in a Berger sphere.Comment: 21 page

    Sharp upper estimates for the first eigenvalue of a Jacobi type operator

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    Our purpose in this article is to obtain sharp upper estimates for the first positive eigenvalue of a Jacobi type operator, which is a suitable extension of the linearized operators of the higher order mean curvatures of a closed hypersurface immersed either in the Euclidean space or in the Euclidean sphere.Brazilian National Research Council (CNPq): grant 303977/2015-9 y grant 308757/2015-7.peerReviewe

    Characterizations of complete linear Weingarten spacelike submanifolds in a locally symmetric semi-Riemannian manifold

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    In this paper, we deal with n-dimensional complete spacelike submanifolds Mn with flat normal bundle and parallel normalized mean curvature vector immersed in an (n + p)-dimensional locally symmetric semi-Riemannian manifold L_p^(n+p) of index p obeying some standard curvature conditions which are naturally satisfied when the ambient space is a semi-Riemannian space form. In this setting, we establish sufficient conditions to guarantee that, in fact, p = 1 and Mⁿ is isometric to an isoparametric hypersurface of L_1^(n+1)having two distinct principal curvatures, one of which is simple.The first author is partially supported by CAPES, Brazil. The second author is partially supported by CNPq, Brazil, grant 303977/2015- 9. The fourth author is partially supported by CNPq, Brazil, grant 308757/2015-7.peerReviewe

    Sharp upper estimates for the first eigenvalue of a Jacobi type operator

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    Our purpose in this article is to obtain sharp upper estimates for the first positive eigenvalue of a Jacobi type operator, which is a suitable extension of the linearized operators of the higher order mean curvatures of a closed hypersurface immersed either in the Euclidean space or in the Euclidean sphere.Brazilian National Research Council (CNPq): grant 303977/2015-9 y grant 308757/2015-7.peerReviewe

    Purification and Preliminary Crystallographic Analysis of a New Lys49-PLA2 from B. Jararacussu

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    BjVIII is a new myotoxic Lys49-PLA2 isolated from Bothrops jararacussu venom that exhibits atypical effects on human platelet aggregation. To better understand the mode of action of BjVIII, crystallographic studies were initiated. Two crystal forms were obtained, both containing two molecules in the asymmetric unit (ASU). Synchrotron radiation diffraction data were collected to 2.0 Å resolution and 1.9 Å resolution for crystals belonging to the space group P212121 (a = 48.4 Å, b = 65.3 Å, c = 84.3 Å) and space group P3121 (a = b = 55.7 Å, c = 127.9 Å), respectively. Refinement is currently in progress and the refined structures are expected to shed light on the unusual platelet aggregation activity observed for BjVIII

    Structural and Functional Studies of a Bothropic Myotoxin Complexed to Rosmarinic Acid: New Insights into Lys49-PLA2 Inhibition

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    Snakebite envenoming is an important public health problem in many tropical and subtropical countries, and is considered a neglected tropical disease by the World Health Organization. Most severe cases are inflicted by species of the families Elapidae and Viperidae, and lead to a number of systemic and local effects in the victim. One of the main problems regarding viperidic accidents is prominent local tissue damage whose pathogenesis is complex and involves the combined actions of a variety of venom components. Phospholipases A2 (PLA2s) are the most abundant muscle-damaging components of these venoms. Herein, we report functional and structural studies of PrTX-I, a Lys49-PLA2 from Bothops pirajai snake venom, and the influence of rosmarinic acid (RA) upon this toxin's activities. RA is a known active component of some plant extracts and has been reported as presenting anti-myotoxic properties related to bothopic envenomation. The myotoxic activity of Lys49-PLA2s is well established in the literature and although no in vivo neurotoxicity has been observed among these toxins, in vitro neuromuscular blockade has been reported for some of these proteins. Our in vitro studies show that RA drastically reduces both the muscle damage and the neuromuscular blockade exerted by PrTX-I on mice neuromuscular preparations (by ∌80% and ∌90%, respectively). These results support the hypothesis that the two effects are closely related and lead us to suggest that they are consequences of the muscle membrane-destabilizing activity of the Lys49-PLA2. Although the C-terminal region of these proteins has been reported to comprise the myotoxic site, we demonstrate by X-ray crystallographic studies that RA interacts with PrTX-I in a different region. Consequently, a new mode of Lys49-PLA2 inhibition is proposed. Comparison of our results with others in the literature suggests possible new ways to inhibit bothropic snake venom myotoxins and improve serum therapy

    Produção da bananeira nanica (1Âș ciclo) em função da aplicação de doses de biofertilizantes lĂ­quidos

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    Objetivou-se com este trabalho, estudar os efeitos de 5 tipos e 10 doses de biofertilizantes na produção da bananeira Nanica (1Âș ciclo). O experimento foi conduzido, em condiçÔes de campo, no CCHA, pertencente a Universidade Estadual da ParaĂ­ba-UEPB, Campus CatolĂ© do Rocha-PB. O delineamento experimental adotado foi o de blocos casualizados, com 50 tratamentos, no esquema fatorial 5 x 10, com quatro repetiçÔes, totalizando 200 parcelas experimentais. O valor do nĂșmero de frutos por planta aumentou com o incremento da dose do biofertilizante B4 atĂ© um limite Ăłtimo; o peso total de pencas por cacho aumentou linearmente com o incremento da dose de biofertilizante, atingindo o valor maior mĂĄximo na dose mĂĄxima; o peso mĂ©dio de penca aumentou linearmente com o incremento da dose do biofertilizante B2, atingindo o maior valor na dose mĂĄxima; o peso mĂ©dio do fruto e o peso do fruto mĂ©dio aumentaram linearmente com o aumento da dose do biofertilizante B5, atingindo os maiores valores na dose mĂĄxima; a aplicação de (B5) proporcionou maior peso mĂ©dio do fruto e peso do fruto mĂ©dio

    a cross-sectional community-based study

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    Funding Information: The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was co-funded by Funda\u00E7\u00E3o para a Ci\u00EAncia e Tecnologia, GHTM-UID/04413/2020 and LA-REAL-LA/P/0117/2020 and by the Flemish Government through the Building Institutional Capacity at the Mozambique INS project. Publisher Copyright: Copyright © 2024 Manafe, Ismael-Mulungo, Ponda, Dos Santos, Mandlate, Cumbe, Mocumbi and Oliveira Martins.Background: Humanitarian emergencies are a major global health challenge with the potential to have a profound impact on people’s mental and psychological health. Displacement is a traumatic event that disrupts families and affects physical and psychological health at all ages. A person may endure or witness a traumatic incident, such as being exposed to war, and, as a result, develop post-traumatic stress disorder (PTSD). There is a lack of information about post-traumatic stress disorder, depression, and anxiety disorder in low and middle-income countries in humanitarian emergency contexts such as Mozambique. This study aimed to assess the prevalence of PTSD, depression, and anxiety, and associated factors among armed conflict survivors in Cabo Delgado, north region of Mozambique in 2023. Methods: A community-based cross-sectional study was conducted between January and April 2023 among 750 participants, who were selected by convenience. A face-to-face interview used the Primary Care Post-Traumatic Stress Disorder Checklist (PC-PTSD-5) to evaluate PTSD, the Generalized Anxiety Disorder Scale (GAD-7) to evaluate anxiety and the Patient Health Questionnaire – Mozambique (PHQ-9 MZ) to evaluate depression. The association between PTSD and demographic and psychosocial characteristics was analyzed using bivariate and multivariable binary logistic regression. We used a 5% significance level. Results: The three mental disorders assessed were highly prevalent in our sample with 74.3% PTSD, 63.8% depression, and 40.0% anxiety. The chance of developing PTSD was higher in females (AOR = 2.30, 95% CI 1.50–3.51), in patients with depression symptoms (AOR = 8.27, 95% CI = 4.97–13.74) and anxiety symptoms (AOR = 1.45, 95% CI = 0.84–2.50). Conclusion: This study reported that the prevalence of PTSD, depression, and anxiety were high. Patients having depressive symptoms, anxiety symptoms, and being female are more at risk of developing PTSD. There is a need to integrate screening for common mental disorders in the context of humanitarian emergencies and its adapted integration of psychosocial interventions.publishersversionpublishe
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