595 research outputs found

    Global solutions and exponential decay for a nonlinear coupled system of beam equations of Kirchhoff type with memory in a domain with moving boundary

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    In this paper we prove the exponential decay in the case n>2n>2, as time goes to infinity, of regular solutions for a nonlinear coupled system of beam equations of Kirchhoff type with memory and weak damping \begin{eqnarray*} &&u_{tt}+\Delta^2 u-M(||\nabla u||^2_{L^2(\Omega_t)}+||\nabla v||^2_{L^2(\Omega_t)})\Delta u\\ &&+\int^{t}_{0}g_1(t-s)\Delta u(s)ds +\alpha u_{t}+h(u-v)=0 \quad \mbox{in} \quad \hat{Q},\\ &&v_{tt}+\Delta^2 v-M(||\nabla u||^2_{L^2(\Omega_t)}+||\nabla v||^2_{L^2(\Omega_t)})\Delta v \\ &&+\int^{t}_{0}g_2(t-s)\Delta v(s)ds + \alpha v_{t}-h(u-v)=0 \quad \mbox{in} \quad \hat{Q} \end{eqnarray*} in a non cylindrical domain of Rn+1\mathbb{R}^{n+1} (n1)(n\ge1) under suitable hypothesis on the scalar functions MM, hh, g1g_1 and g2g_2, and where α\alpha is a positive constant. We show that such dissipation is strong enough to produce uniform rate of decay. Besides, the coupling is nonlinear which brings up some additional difficulties, which plays the problem interesting. We establish existence and uniqueness of regular solutions for any n1n\ge 1

    Juicio político y presunción de verdad

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    This article presents Hanna Arendt’s theory about political judgement, i.e., the expresion of the discursive reason in the political sphere. A certain lack of faith in the public exercise of discursive reason, motivated by her negative experience of totalitarism, leads Arendt to adopt a skeptical and Kantian conception of judgement, which only leaves place for a human action and freedom shorn of rationality in the political arena

    Clinicopathological and toxicological aspects of poisoning by the clomazone herbicide in sheep

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    AbstractClomazone (2-[(2-chlorophenyl)methyl]-4,4-dimethyl-3-isoxazolidinone) is a herbicide which has been widely used in southern Brazil in the rice cultivation and can be toxic for humans and animals. This study reports the first outbreak poisoning due to clomazone in a flock of 103 sheep, 20 of which showed mainly neurological and respiratory signs. Clomazone was detected in soil and vegetation samples and in the liver, kidney and muscles of poisoned animals. The poisoning was experimentally reproduced in three sheep by the administration of a 134mgkg body weight dose of clomazone. In both the natural and experimental cases, the clinical signs included tachypnea, anorexia, somnolence, weakness and ataxia. Macroscopically, there were no significant changes. Histologically, vacuolization in the white matter, perineuronal vacuoles and congestion of the leptomeningeal and brain vessels were observed. Ultrastructurally, the vacuolar lesions in the brain corresponded to swelling of the dendrites and astrocytic processes. It is concluded that clomazone causes toxic neuropathy in sheep

    CONCEITO DA PROFUNDIDADE DE MISTURA GERADA PELA AÇÃO DE ONDAS APLICADO À LAGOA DA MANGUEIRA

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    O termo profundidade de mistura é definido como a profundidade máxima afetada pela onda ao se propagar. Esse conceito é aplicado à lagoa Mangueira, uma lagoa costeira rasa, fechada e sem efeito de maré. Como a profundidade máxima é de 6m e que vento de intensidade superior a 5m/s atingem profundidades superiores a 4,7m na direção mais desfavorável, conclui-se tratar-se de local que dificilmente atinge uma condição de estratificação térmica, devendo ser comum a ressuspensão de sedimentos do fundo

    Diagnóstico Pré-natal de Síndrome de Wolf-Hirschhorn: a propósito de um caso

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    Introdução: O Síndrome de Wolf-Hirschhorn é uma patologia originada por uma deleção da região terminal do braço curto do cromossoma 4. O tamanho da deleção pode ser variável levando a um espectro alargado de manifestações clínicas. Em diagnóstico pré-natal (DPN), as alterações fetais mais frequentes incluem atraso do crescimento intra-uterino, lábio leporino e/ou fenda do palato e anomalias cardíacas. A prevalência estimada é de 1/50.000 nascimentos afetando duas vezes mais indivíduos do sexo feminino do que do sexo masculino. Objectivo: Apresentação de um caso de Síndrome de Wolf-Hirschhorn em DPN comparando-o com outros casos publicados. Material e métodos: Grávida com 17semanas de gestação, referenciada para estudos cromossómicos por idade materna avançada (35 anos) e rastreio bioquímico positivo para trissomia 18. A análise citogenética convencional dos amniócitos cultivados foi realizada de acordo com os métodos habituais usando bandas GTG. O estudo foi complementado por técnicas de citogenética molecular (FISH) utilizando-se a sonda específica para a região do Síndrome de Wolf-Hirschhorn. Resultados: O estudo cromossómico efetuado, revelou uma deleção na região terminal do braço curto do cromossoma 4. A análise por FISH confirmou a existência da deleção desta região, permitindo estabelecer o cariótipo 46,XX,del(4)(p15.3).ish del(4)(p16.3p16.3)(WCHR-). Os cariótipos efetuados aos pais foram normais. Conclusões: Discute-se a importância deste caso pela raridade da anomalia citogenética encontrada, assim como pela dificuldade em realizar o diagnóstico por citogenética convencional, em alguns destes casos, quando não se obtêm bandas de alta resolução

    Clinical, cytogenetic and molecular findings of a “de novo” inv dup del (6q)

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    Introduction: Complex rearrangements resulting in inverted duplications contiguous to a terminal deletion (inv dup del) were first reported for the short arm of chromosome 8 in1976. Since then this type of structural anomaly has been described for an increasing number of chromosomes. In these rearrangements, the concomitant presence of a deletion and a duplication has important consequences in genotype-phenotype correlations. The authors describe the clinical findings and the cytogenetic characterization of a rare inv dup del involving the long arm of chromosome 6. Material and methods: A girl aged 5 was referred for subtelomeric studies with the indication of psychomotor retardation, autistic features and stereotipies. Chromosome analysis with high resolution GTL-banding was performed on metaphases obtained from cultured peripheral blood lymphocytes. Molecular studies included MLPA (Kits P036 and P070, MRC-Holland), FISH with subtelomeric and whole chromosome painting probes specific for chromosome 6, and cCGH techniques. Results: Initial MLPA studies detected a subtelomeric deletion in the long arm of chromosome 6; the subsequent karyotype revealed a structurally abnormal chromosome 6 with additional material in the end of the long arm. FISH analysis showed the deletion and demonstrated that the extra material was derived from chromosome 6; cCGH tecnhiques defined the extension and confirmed the breakpoints of the duplicated segment. Thus this rearrangement was interpreted as an inv dup del (6q). Since parental karyotypes were normal, this anomaly was considered “de novo”. Discussion: As far as we know this is the first description of a patient presenting with a “de novo” inv dup del (6q). We compare the clinical features in this child with the previously reported cases with either an isolated terminal deletion or a duplication of distal 6q. The authors enhance the importance of the combination of high resolution banding with molecular studies in the characterization of this rare rearrangement

    Immunophenotype and TCR‐Vbeta repertoire of peripheral blood T‐cells in acute infectious mononucleosis.

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    Blood Cells Mol Dis. 2003 Jan-Feb;30(1):1-12. Immunophenotype and TCR-Vbeta repertoire of peripheral blood T-cells in acute infectious mononucleosis. Lima M, Teixeira Mdos A, Queirós ML, Santos AH, Gonçalves C, Correia J, Farinha F, Mendonça F, Soares JM, Almeida J, Orfão A, Justiça B. Service of Clinical Haematology, Hospital Santo António, Porto, Portugal. [email protected] Abstract Although a number of studies on the phenotypic changes that occur after T-cell activation have already been published, the specific immunophenotypic features of T-lymphocytes and the frequency at which TCR-variable region (TCR-V) restricted T-cell expansions occur "in vivo" during acute viral infection still remains to be established. We report on the immunophenotype and TCR-V repertoire of peripheral blood T-cells from 28 patients with acute infectious mononucleosis. Immunophenotypic studies were performed by flow cytometry using direct immunofluorescence techniques and stain-and-then-lyse sample preparation protocols with three- and four-colour combinations of monoclonal antibodies directed against a large panel of T- and NK-cell associated markers, activation- and adhesion-related molecules and TCR-Vbeta, -Vgamma and -Vdelta families. Nearly all patients (27/28) showed a massive expansion of CD8(+)/TCRalphabeta(+) T cells, the majority (>90%) of which displayed an immunophenotype compatible with T-cell activation: CD2(+high), CD7(+low), CD11a(+high), CD38(+high), HLA-DR(+high), CD28(+/-low), CD45RO(+high), CD45RA(-/+low), CD11b(-/+low), CD11c(+/-low), CD16(-), CD56(-), CD57(-), CD62L(-), CD94(-), CD158a(-), CD161(-), NKB1(-). Additionally, the levels of both CD3 and CD5 were slightly decreased compared to those found in normal individuals. Late-activation antigens, such as CD57, were found in small proportions of CD8(+)/TCRalphabeta(+) T-cells. Increased numbers of CD4(+)/TCRalphabeta(+) T-cells, TCRgammadelta(+) T-cells and NK-cells were also noticed in 17, 16 and 13 of the 28 cases studied, respectively. Evidence for activation of CD4(+)/TCRalphabeta(+) and TCRgammadelta(+) T-cells relied on changes similar to those described for CD8(+)/TCRalphabeta(+) although less pronounced, except for higher levels of both CD5 and CD28 in the absence of reactivity for CD11c on CD4(+)/TCRalphabeta(+) T-cells and higher levels of CD161 and CD94 on TCRgammadelta(+) T-cells. Small expansions of one or more TCR-Vbeta families accounting for 12 +/- 7% of either the CD8(+)/TCRalphabeta(+) or the CD4(+)/TCRalphabeta(+) T-cell compartment were found in 12 of 14 patients studied, whereas the distribution of the TCR-Vgamma and -Vdelta repertoires tested in 2 of the individuals with expanded TCRgammadelta(+) T-cells was similar to that observed in control individuals. The results presented here provide evidence for an extensive T-cell activation during acute viral infection and establish the immunophenotype patterns associated with this condition. PMID: 12667982 [PubMed - indexed for MEDLINE

    Thermodynamic characterization of deep eutectic solvents at high pressures

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    Despite the large spectrum of applications being reported for DESs over the last decade, their thermodynamic characterization is often neglected, hindering a better understanding of their nature, and the development of accurate and robust thermodynamic models to describe them, essential for the conceptual and design stages of new industrial processes. This work aims at decreasing such a gap in literature by reporting new experimental density and viscosity data in wide temperature and pressure ranges for the three archetypal DESs of cholinium chloride, as hydrogen bond acceptor, combined with either ethylene glycol, glycerol, or urea, as hydrogen bond donor. The experimental data measured in this work were then correlated using the Perturbed Chain - Statistical Associating Fluid Theory equation of state coupled with the Free Volume Theory to assess the performance of existing coarse-grained models when applied to the description of DESs. The modelling results obtained highlight the limitation of the existing models, since a correct prediction of DES density could not be achieved, reinforcing the need for viable alternative approaches for the development of coarse-grained models that are appropriate for the thermodynamic modelling of DESs.publishe

    Isolation of Besnoitia besnoiti from infected cattle in Portugal

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    Abstract Besnoitia besnoiti, an obligate intracellular protozoan parasite belonging to the phylum apicomplexa, is the causative agent of bovine besnoitiosis. Besnoitiosis is responsible for significant losses in the cattle industry of Africa and Mediterranean countries due to the high morbidity rate, abortion and infertility in males. The acute stage of disease is associated with the proliferative forms (tachyzoites) and is characterized by fever, whimpery, general weakness and swelling of the superficial lymph nodes. During the following chronic stage, a huge number of cysts are formed mainly in the subcutaneous tissues. This process is non-reversible, and chronic besnoitiosis is characterized by hyper-sclerodermia, hyperkeratosis, alopecia and, in bulls, atrophy, sclerosis and focal necrosis that cause irreversible lesions in the testis. In this paper we report on the identification of large cysts in the skin of a cow and a bull in Portugal, which presented loss of hair and enlargement and pachydermis all over the body. The observation of a two-layered cyst wall within the host cell, the encapsulation of the host cell by a large outer cyst wall, and the subcutaneous localization of the cysts within the host, were characteristic for B. besnoiti. The parasites were isolated from the infected animals and successfully propagated in Vero cells without prior passages in laboratory animals. Morphological characterization of B. besnoiti tachyzoites and the amplification of the 149 bp segment from the internal transcribed spacer 1 (ITS1), aided with specific primers, confirmed the identification of B. besnoiti. Keywords: Besnoitia besnoiti; Bovine besnoitiosis; Portugal; Cyst; In vitro cell cultur
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