452 research outputs found

    Enhancement of the critical temperature in iron-pnictide superconductors by finite size effects

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    Recent experiments have shown that, in agreement with previous theoretical predictions, superconductivity in metallic nanostructures can be enhanced with respect to the bulk limit. Motivated by these results we study finite size effects (FSE) in an iron-pnictide superconductor. For realistic values of the bulk critical temperature Tc ~ 20-50K, we find that, in the nanoscale region L ~ 10 nm, Tc(L) has a complicated oscillating pattern as a function of the system size L. A substantial enhancement of Tc with respect to the bulk limit is observed for different boundary conditions, geometries and two microscopic models of superconductivity. Thermal fluctuations, which break long range order, are still small in this region. Finally we show that the differential conductance, an experimental observable, is also very sensitive to FSE.Comment: 4 pages, 3 figure

    Specificity in S-Nitrosylation: a short-range mechanism for NO signaling?

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    Significance: Nitric oxide (NO) classical and less classical signaling mechanisms (through interaction with soluble guanylate cyclase and cytochrome c oxidase, respectively) operate through direct binding of NO to protein metal centers, and rely on diffusibility of the NO molecule. S-Nitrosylation, a covalent post-translational modification of protein cysteines, has emerged as a paradigm of nonclassical NO signaling. Recent Advances: Several nonenzymatic mechanisms for S-nitrosylation formation and destruction have been described. Enzymatic mechanisms for transnitrosylation and denitrosylation have been also studied as regulators of the modification of specific subsets of proteins. The advancement of modification-specific proteomic methodologies has allowed progress in the study of diverse S-nitrosoproteomes, raising clues and questions about the parameters for determining the protein specificity of the modification. Critical Issues: We propose that S-nitrosylation is mainly a short-range mechanism of NO signaling, exerted in a relatively limited range of action around the NO sources, and tightly related to the very controlled regulation of subcellular localization of nitric oxide synthases. We review the nonenzymatic and enzymatic mechanisms that support this concept, as well as physiological examples of mammalian systems that illustrate well the precise compartmentalization of S-nitrosylation. Future Directions: Individual and proteomic studies of protein S-nitrosylation-based signaling should take into account the subcellular localization in order to gain further insight into the functional role of this modification in (patho)physiological settings. Antioxid. Redox Signal. 19, 1220-1235.Spanish Government [CSD2007-00020, CP07/00143, PS09/00101, SAF2009-7520, PI10/02136]; Spanish-Portuguese Integrated Action Grant [PRI-AIBPT-2011-1015/E-10/12]; Foundation for Science and Technology (FCT, Portugal) [PTDC/SAU-NEU/102612/2008, PTDC/SAU-NMC/112183/2009, PEst-OE/EQB/LA0023/2011]; COST action [BM1005]info:eu-repo/semantics/publishedVersio

    A review of Cushing’s disease treatment by the Department of Neuroendocrinology of the Brazilian Society of Endocrinology and Metabolism

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    The treatment objectives for a patient with Cushing’s disease (CD) are remission of hypercortisolism, adequate management of co-morbidities, restoration of the hypothalamic-pituitary-adrenal axis, preservation of fertility and pituitary function, and improvement of visual defects in cases of macroadenomas with suprasellar extension. Transsphenoidal pituitary surgery is the main treatment option for the majority of cases, even in macroadenomas with low probability of remission. In cases of surgical failure, another subsequent pituitary surgery might be indicated in cases with persistent tumor imaging at post surgical magnetic resonance imaging (MRI) and/or pathology analysis of adrenocorticotropic hormone-positive (ACTH+) positive pituitary adenoma in the first procedure. Medical treatment, radiotherapy and adrenalectomy are the other options when transsphenoidal pituitary surgery fails.There are several options of medical treatment, although cabergoline and ketoconazole are the most commonly used alone or in combination. Novel treatments are also addressed in this review. Different therapeutic approaches are frequently needed on an individual basis, both before and, particularly, after surgery, and they should be individualized. The objective of the present review is to provide the necessary information to achieve a more effective treatment for CD. It is recommended that patients with CD be followed at tertiary care centers with experience in treating this condition

    Pathogenicity and aggressiveness of Colletotrichum gloeosporioides isolates in ornamental pepper

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    Anthracnose, a disease caused by fungi of the Colletotrichum genus, affects many crops, including ornamental plants. This study aimed at evaluating the pathogenicity and aggressiveness of the Colletotrichum gloeosporioides Penz. (Sacc.) isolates Cg1 (papaya), Cg2 (guava) and Cg3 (mango) in the ornamental pepper varieties Stromboli, Etna and Pirâmide, during two different periods (July/August and November/December 2013). The fungi pathogenicity and the severity of plant symptoms were assessed using a grading scale. The three C. gloeosporioides isolates were pathogenic to the three ornamental pepper varieties studied, exhibiting different levels of aggressiveness among them. The environmental conditions influenced the isolates aggressiveness, with the most severe symptoms observed in the second assessment period

    Macrossismicity associated with the Arraiolos earthquake of January 15, 2018 with M = 4.9 and possible implications in the geometry of the rupture

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    RESUMO: Na segunda quinzena de janeiro de 2018 realizou-se um estudo da macrossismicidade associada ao sismo de Arraiolos de dia 15 de janeiro. No presente trabalho descreve-se a metodologia usada na recolha de informação, o tratamento dos dados e a sua representação na forma de mapa de intensidades. A distribuição geográfica das intensidades mostra um alongamento da isossista de intensidade IV na direção N-S e no sentido sul. Este alongamento poderá estar relacionado com uma variação lateral da atenuação, ou com um efeito de sítio. Outra hipótese, menos provável, é que este padrão se deva ao efeito de diretividade originado por uma rutura unilateral com propagação de norte para sul, ao longo de um plano do mecanismo focal. Esta possibilidade, conjugada com evidências para a existência de estruturas ativas WNW-ESE descritas em trabalhos anteriores, levanta a hipótese do designado “cluster sísmico de Arraiolos” estar associado a uma interseção de falhas ativas.ABSTRACT: We performed a study about the macrossismicity associated to the Arraiolos (Portugal) earthquake, that occurred on January 15th, (M = 4.9), in order to construct a map of seismic intensities. The fieldwork took place in the second half of January, using the questionnaire available in the website of the Portuguese Institute of the Sea and the Atmosphere (IPMA). We provided the same questionnaire on the internet, and collected responses from many parts of the country. The results obtained allowed to construct a map of intensities showing a clear elongation of the intensities in a N-S direction. This orientation can be explained by the differences in the behaviour of seismic waves depending on the nature of the rocks or by a directivity effect associated with the rupture along a fault with this direction. On the one hand, an earthquake of magnitude 4.9 will hardly have the capacity to produce a directivity effect, however on the other hand the analysis of the Portuguese Geological Map seems to discard the first hypothesis. The IPMA provides on its website, a strike slip focal mechanism for this earthquake (E-W dextral and N-S sinistral). The conjugation of this focal mechanism with the distribution of intensities, seems to reinforce the hypothesis of rupture along an N-S fault plane. Similar focal mechanisms are known, associated with other earthquakes that occurred in this region, but previous works propose that they are related, not toN-Sruptures, buttoWNW-ESE structures present in the region, with geological and geomorphological evidence of recent tectonic activity. In this type of studies, there is always a factor ofsubjectivity inherent to the sensitivity of the people who were questioned, so these data are not sufficient to clearly affirm that the earthquake occurred associated with a N-S-trending fault. The combination of these data with the information published in previous works allows to consider the possibility that the "Arraiolos seismic cluster" corresponds to an intersection of active WNW-ESE and N-S strike slip faults. Assuming that there are alternating ruptures in both systems, temporary block occurs in the system that has been cut, leading to a local stress concentration. Though, a movement that in depth can be ductile, aseismic throughout most of the area of the faults, in the zone of intersection of the two systems the crust will have to respond necessarily as brittle, generating earthquakes and explaining the existence of this seismic cluster.info:eu-repo/semantics/publishedVersio

    Didactic Sequence for Teaching Exponential Function

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    This paper presents a methodological proposal for the teaching of exponential function, resulting from the application of a didactic sequence involving exponential function, where evidence of learning and the consolidation and application of mathematical concepts in problem solving were identified and analyzed. The Didactic Engineering of Michèle Artigue (1988) was used as a research methodology. As theoretical contributions that guided and enabled the development of the research, we chose the use of Mathematical Investigation in the classroom; Didactic Sequence in the conception of Zabala (1999); the Articulated Units of Conceptual Reconstruction proposed by Cabral (2017) and assumptions of Vygotsky\u27s theory. A didactic sequence composed of five UARC\u27s was elaborated to work the exponential function, with a view to minimizing the difficulties naturally imposed by the content to be explained. Microgenetic analysis of verbal interactions between teacher and students was used to analyze the results of the application. The results show that the students participating in the experiment showed evidence of learning, recorded during the process, and began to have a good understanding of the concepts and properties related to the topic, in addition to a good performance in carrying out the activities, facts that corroborate the potential of the didactic sequence proposed herein

    Analysis of the relationship between life expectancy and social determinants in a north-eastern region of Brazil, 2010-2017

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    The process of population aging is a worldwide reality becoming a global public health challenge. Although population aging is especially noticeable in more developed regions, there has also been a significant advance in the quantity of elderly people in areas with unfavourable socioeconomic indicators, and a rapid growth in countries with a low level of economic development. This article presents an analysis based on spatial autocorrelation of the relationship between life expectancy and social determinants in a north-eastern region of Brazil. An ecological study was conducted using the secondary data of social, demographic, and health indicators of elderly people collected in the Brazilian Demographic Census of the 75 municipalities of the state of Sergipe. Spatial autocorrelation was evaluated using the Moran global index and the local indicators of space association. Multiple linear regression models were used to identify the relationship between life expectancy and social determinants. The South-eastern region of the state presented clusters with all indicators pointing to acceptable lifestyles, whereas the municipalities of the north-western and far-eastern regions were characterized by values demonstrating precarious living conditions. The high dependency ratio, illiteracy rate, and unemployment rate among elderly people had a negative impact on life expectancy. The evidence confirms that there is an autocorrelation between social determinants and life expectancy, indicating that the worse the social, economic, and health indicators are, the lower the life expectancy. This finding indicates the need to redirect public policies and formulate strategies aimed at reducing social and health inequalities

    Escala de resultados de Glasgow por ocasião da alta hospitalar como indicador prognóstico em pacientes com traumatismo cranioencefálico grave

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    OBJECTIVE: Evaluate the Glasgow outcome scale (GOS) at discharge (GOS-HD) as a prognostic indicator in patients with traumatic brain injury (TBI). METHOD: Retrospective data were collected of 45 patients, with Glasgow coma scale <8, age 25±10 years, 36 men, from medical records. Later, at home visit, two measures were scored: GOS-HD (according to information from family members) and GOS LATE (12 months after TBI). RESULTS: At discharge, the ERG showed: vegetative state (VS) in 2 (4%), severe disability (SD) in 27 (60%), moderate disability (MD) in 15 (33%) and good recovery (GR) in 1 (2%). After 12 months: death in 5 (11%), VS in 1 (2%), SD in 7 (16%), MD in 9 (20%) and GR in 23 (51%). Variables associated with poor outcome were: worse GOS-HD (p=0.03), neurosurgical procedures (p=0.008) and the kind of brain injury (p=0.009). CONCLUSION: The GOS-HD was indicator of prognosis in patients with severe TBI.OBJETIVO: Avaliar a escala de resultados de Glasgow (ERG) à alta hospitalar (ERG-ALTA) como indicador prognóstico em pacientes com traumatismo cranioencefálico (TCE). MÉTODO: Dados retrospectivos de 45 pacientes (36 homens), com escala de coma de Glasgow <8, idade 25±10 anos, foram coletados do prontuário médico. Posteriormente, em visita domiciliar, foram pontuadas duas medidas: ERG-ALTA (de acordo com informações de familiares) e ERG TARDIA (após 12 meses do TCE). RESULTADOS: Por ocasião da alta hospitalar, a ERG evidenciou: estado vegetativo (EV) em 2 (4%); incapacidade grave (IG) em 27 (60%), incapacidade moderada (IM) em 15 (33%) e boa recuperação (BR) em 1 (2%). Após 12 meses: morte em 5 (11%), EV em 1 (2%), IG em 7 (16%), IM em 9 (20%) e BR em 23 (51%). Variáveis associadas com má evolução foram: pior ERG-ALTA (p=0,03); procedimentos neurocirúrgicos (p=0,008) e o tipo de lesão cerebral (p=0,009). CONCLUSÃO: A ERG-ALTA foi indicador adequado de prognóstico tardio em pacientes com TCE grave.60460
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