461 research outputs found

    Potts model with q=3 and 4 states on directed Small-World network

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    Monte Carlo simulations are performed to study the two-dimensional Potts models with q=3 and 4 states on directed Small-World network. The disordered system is simulated applying the Heat bath Monte Carlo update algorithm. A first-order and second-order phase transition is found for q=3 depending on the rewiring probability pp, but for q=4 the system presents only a first-order phase transition for any value pp . This critical behavior is different from the Potts model on a square lattice, where the second-order phase transition is present for q4q\le4 and a first-order phase transition is present for q>4.Comment: 5 pages, 8 figures. arXiv admin note: text overlap with arXiv:1001.184

    One Dimensional Chain with Long Range Hopping

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    The one-dimensional (1D) tight binding model with random nearest neighbor hopping is known to have a singularity of the density of states and of the localization length at the band center. We study numerically the effects of random long range (power-law) hopping with an ensemble averaged magnitude \expectation{|t_{ij}|} \propto |i-j|^{-\sigma} in the 1D chain, while maintaining the particle-hole symmetry present in the nearest neighbor model. We find, in agreement with results of position space renormalization group techniques applied to the random XY spin chain with power-law interactions, that there is a change of behavior when the power-law exponent σ\sigma becomes smaller than 2

    Levantamento das patologias e monitorização do Arco-Cruzeiro da Igreja da Misericórdia de Aveiro

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    O estado de conservação das construções tradicionais motiva para um crescente interesse na recuperação e manutenção do património construído. Antes de mais, é importante obter uma visão geral da evolução temporal das construções permitindo assim a caracterização dos diversos aspectos estruturais e construtivos. Este trabalho foi desenvolvido com o objectivo de estudar as patologias associadas à nave principal da Igreja da Misericórdia de Aveiro e em particular as patologias associadas ao Arco-Cruzeiro que se encontra no interior desta, com o intuito de se estabelecer a melhor estratégia de monitorização dos danos estruturais a aplicar. Como resultado desta análise foi proposto e implementado um plano de monitorização, com o desenvolvimento de meios de instrumentação, que permitem monitorizar o comportamento estrutural do arco, de forma não intrusiva, garantindo a reversibilidade e a eventual futura extensão da instrumentação. Foi ainda desenvolvido um modelo numérico em elementos finitos que serviu de apoio à interpretação das causas dos danos estruturais encontrados

    Transforming growth factor-β (TGF-β) maintains follicular ultrastructure and stimulates preantral follicle growth in caprine ovarian tissue cultured in vitro

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    O objetivo desse estudo foi investigar se o TGF-β afeta a sobrevivência, ativação e crescimento de folículos primordiais caprinos inclusos no córtex ovariano após o cultivo in vitro. Ovários de cabras foram coletados em abatedouro e fragmentos de tecido ovariano foram cultivados por um e sete dias em meio essencial mínimo alfa (α-MEM+) sozinho ou suplementado com TGF-β (1, 5, 10 ou 50ng/mL). Fragmentos ovarianos não cultivados e cultivados foram processados para análise histológica e ultraestrutural. Os resultados mostraram que, comparado ao controle fresco, houve diminuição no percentual de folículos morfologicamente normais em todos os tratamentos somente após sete dias de cultivo. O TGF-β não afetou a ativação folicular independente da concentração testada, contudo, o diâmetro folicular foi superior (P<0.05) no tratamento com 10ng/mL de TGF-β quando comparado ao controle fresco e aos demais tratamentos. Além disso, essa mesma concentração manteve a ultraestrutura normal dos folículos após sete dias de cultivo. Em conclusão, o TGF-β apresentou efeito adicional no crescimento folicular e na manutenção da integridade ultraestrutural de folículos pré-antrais caprinos inclusos no tecido ovariano quando utilizado na concentração de 10ng/mL durante sete dias de cultivo.The objectives of this study were to investigate whether TGF-β affect the survival, activation and further growth of goat primordial follicles enclosed in ovarian cortex after in vitro culture. Goat ovaries were collected from an abattoir and pieces of ovarian tissues were cultured for one or seven days in a supplemented alpha Minimum Essential Medium, alone or containing TGF-β (1, 5, 10 or 50ng/mL). Ovarian tissues from the fresh control as well as those cultured were processed for histological and ultrastructural studies. The results showed that when compared with fresh control, there was decrease in the percentages of histologically normal follicles in all treatments only after seven days culture. TGF-β did not affect the activation of preantral follicles regardless of its concentration, however, larger follicles diameter (P<0.05) was observed using 10ng/mL TGF-β than in the fresh control and other treatments. Moreover, this concentration maintained the normal ultrastructure after seven days of culture. In conclusion, TGF-β showed additional effect on the follicle growth and the maintenance of ultrastructural integrity of goat preantral follicles enclosed in ovarian tissue when used at 10ng/mL during seven days of culture

    Myocardial T1 mapping and extracellular volume quantification in patients with left ventricular non-compaction cardiomyopathy

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    Aims: From pathophysiological mechanisms to risk stratification and management, much debate and discussion persist regarding left ventricular non-compaction cardiomyopathy (LVNC). This study aimed to characterize myocardial T1 mapping and extracellular volume (ECV) fraction by cardiovascular magnetic resonance (CMR), and investigate how these biomarkers relate to left ventricular ejection fraction (LVEF) and ventricular arrhythmias (VA) in LVNC. Methods and results: Patients with LVNC (n = 36) and healthy controls (n = 18) were enrolled to perform a CMR with T1 mapping. ECV was quantified in LV segments without late gadolinium enhancement (LGE) areas to investigate diffuse myocardial fibrosis. Patients with LVNC had slightly higher native T1 (1024 ± 43 ms vs. 995 ± 22 ms, P = 0.01) and substantially expanded ECV (28.0 ± 4.5% vs. 23.5 ± 2.2%, P &lt; 0.001) compared to controls. The ECV was independently associated with LVEF (β = -1.3, P = 0.001). Among patients without LGE, VAs were associated with higher ECV (27.7% with VA vs. 25.8% without VA, P = 0.002). Conclusion: In LVNC, tissue characterization by T1 mapping suggests an extracellular expansion by diffuse fibrosis in myocardium without LGE, which was associated with myocardial dysfunction and VA, but not with the amount of non-compacted myocardium

    Exploratory Behavior, Trap Models and Glass Transitions

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    A random walk is performed on a disordered landscape composed of NN sites randomly and uniformly distributed inside a dd-dimensional hypercube. The walker hops from one site to another with probability proportional to exp[βE(D)]\exp [- \beta E(D)], where β=1/T\beta = 1/T is the inverse of a formal temperature and E(D)E(D) is an arbitrary cost function which depends on the hop distance DD. Analytic results indicate that, if E(D)=DdE(D) = D^{d} and NN \to \infty, there exists a glass transition at βd=πd/2/Γ(d/2+1)\beta_d = \pi^{d/2}/\Gamma(d/2 + 1). Below TdT_d, the average trapping time diverges and the system falls into an out-of-equilibrium regime with aging phenomena. A L\'evy flight scenario and applications to exploratory behavior are considered.Comment: 4 pages, 1 figure, new versio

    Genetic Diversity Of Pacu And Piapara Broodstocks In Restocking Programs In The Rivers Paraná And Paranapanema (brazil)

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    The genetic diversity of Piaractus mesopotamicus (pacu) and Leporinus elongatus (piapara) broodstocks used in restocking programs in the rivers Paraná and Paranapanema is analyzed. One hundred and twenty specimens (two broodstocks of each species) from fish ponds in Palotina PR Brazil and in Salto Grande SP Brazil were assessed. Ten primers produced 96 fragments, comprising 68 (70.83%) and 94 (97.92%) polymorphic fragments for P. mesopotamicus and L. elongatus broodstocks, respectively. Differences (p <0.05) in the frequency of 15 and 27 fragments were detected for each species, without exclusive fragments. Shannon Index (0.347-0.572) and the percentage of polymorphic fragments (57.3%-94.8%) revealed high intra-population genetic variability for all broodstocks. Results of molecular variance analyses (AMOVA) showed that most variations do not lie between the broodstocks but within each broodstock (89%). Genetic (0.088 and 0.142) and identity (0.916 and 0.868) distance rates demonstrated similarity between the broodstocks of each species, corroborated by Fst (0.1023 and 010.27) and Nm (4.18 and 4.33) rates, with a slight genetic difference due to genic flux. High intrapopulation genetic variability and similarity between the broodstocks of each species was also detected, proving a common ancestry.3742365237

    In vitro development of primordial follicles after long-term culture of goat ovarian tissue

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    This study aims to investigate the effects of follicle stimulating hormone (FSH) and fibroblast growth factor-2 (FGF-2) on the survival and growth of caprine preantral follicles. Ovarian tissues were cultured for 1, 7, 14, 21 or 28 days in medium supplemented with FSH (FSH-2d or FSH-7d, i.e., with replacement of the culture medium every 2 or 7 days, respectively) or FSH + FGF-2 (replacement of the medium every 2 days). Non-cultured (control) and cultured ovarian fragments were processed for histological and ultrastructural analysis. After 28 days of culture, the media supplemented with FSH-2d was the most effective in maintaining the percentage of normal follicles and in promoting follicular growth. Furthermore, both treatments with FSH increased the percentage of the primary follicles. However, ultrastructural studies did not confirm follicular integrity from 14 days of culture onward. In conclusion, culturing tissue for up to 7 days in medium containing FSH alone or combined with FGF-2 maintains caprine preantral follicle integrity and promotes their growth in vitro

    Sphingosine 1-phosphate promotes activation of aprine preantral follicle in vitro

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    Este estudo descreve o efeito da esfingosina 1-fosfato (S1P) no desenvolvimento de folículos pré-antrais, portanto da ativação e viabilidade de folículos caprinos cultivados in vitro. Fragmentos de ovários foram cultivados por um ou sete dias em meio essencial mínimo com diferentes concentrações de S1P (0, 1, 10, 50, 100 ou 200ng/mL). Os fragmentos de ovário foram processados para análise histológica em microscopia óptica, microscopia eletrônica e microscopia de fluorescência. O tratamento usando 1ng/mL de S1P foi capaz de manter a porcentagem de folículos normais durante o período de cultivo de sete dias. Ao final do período de cultivo, houve uma redução significativa (p<0,05) na porcentagem de folículos primordiais em todos os grupos tratados com S1P, comparados com os grupos controle (FC e CC), seguida por um aumento do número de folículos ativados (intermediários, primários e secundários). Adicionalmente, na cultura por sete dias com meio suplementado com S1P (1ng/mL), houve preservação da ultraestrutura das organelas e manteve-se a viabilidade dos folículos pré-antrais avaliados por microscopia de fluorescência. Em conclusão, após sete dias de cultura, o meio suplementado com 1ng/mL de S1P ativa o desenvolvimento de folículos pré-antrais de caprino, cultivados in situ e mantém as viabilidades oocitária e folicular.This study describes the effect of sphingosine 1-phosphate (S1P) for development of preantral follicle, therefore the activation and follicular viability of caprine follicles cultured in vitro. Ovarian fragments were cultured for 1 or 7 days in Minimum Essential Medium with different S1P concentrations (0, 1, 10, 50, 100 or 200ng/mL). All ovarian fragments were processed for histological analysis in optical microscopy, transmission electron microscopy and fluorescence analysis. The treatment using 1ng/mL of S1P was able to maintain the percentage of normal follicles with the progression of the culture from day 1 to 7. At end of the 7-day culture period there was a significant reduction (P<0.05) in the percentage of primordial follicles in all groups treated with S1P, compared with fresh control (FC) and Control Culture (CC), which was followed by an increase of activated follicles (intermediary, primary and secondary). In addition, the culture for 7 days with media supplemented with S1P with 1ng/mL preserved the ultrastructure of organelles and kept the preantral follicular viability when evaluated by fluorescence microscopy. In conclusion, after 7 days of culture, the 1ng/mL of S1P activates the development of preantral caprine follicles, cultured in situ and maintains the oocitary and follicular viability

    Cross-cultural validity of the Animated Activity Questionnaire for patients with hip and knee osteoarthritis: a comparison between the Netherlands and Brazil

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    Background: The Animated Activity Questionnaire (AAQ) was developed in the Netherlands to assess activity limitations in individuals with hip/knee osteoarthritis (HKOA). The AAQ is easy to implement and minimizes the disadvantages of questionnaires and performance-based tests by closely mimicking real-life situations. The AAQ has already been cross-culturally validated in six other countries. Objective: To assess the cross-cultural validity, the construct validity, the reliability of the AAQ in a Brazilian sample of individuals with HKOA, and the influence of formal education on the construct validity of the AAQ. Methods: The Brazilian sample (N = 200), mean age 64.4 years, completed the AAQ and the Western Ontario and McMaster Universities Index (WOMAC). A subgroup of participants performed physical function tests and completed the AAQ twice with a one-week interval. The Dutch sample (N = 279) was included to examine Differential Item Functioning (DIF) between the scores obtained in the Netherlands and Brazil. For this purpose, ordinal regression analyses were used to evaluate whether individuals with the same level of activity limitations from the two countries (the Dutch as the reference group) scored similarly in each AAQ item. To evaluate the construct validity, correlation coefficients were calculated between the AAQ, the WOMAC domains, and the performance-based tests. To evaluate reliability, the Cronbach's alpha coeffi-cient, the intraclass correlation coefficient, and the standard error of measurement (SEM) were calculated. Results: The AAQ showed significant correlations with all the WOMAC domains and performance -based tests (rho=0.46-0.77). The AAQ showed high internal consistency (Cronbach's alpha=0.94), excellent test-retest reliability (ICC2,1 = 0.98), and small SEM (2.25). Comparing to the scores from the Netherlands, the AAQ showed DIF in two items, however, they did not impact on the total AAQ score (rho=0.99). Conclusion: Overall, the AAQ showed adequate cross-cultural validity, construct validity, and reliability, which enables its use in Brazil and international/multicenter studies. (c) 2021 Associacao Brasileira de Pesquisa e Pos-Graduacao em Fisioterapia. Published by Elsevier Espana, S.L.U. All rights reserved.Orthopaedics, Trauma Surgery and Rehabilitatio
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