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Search Results: 1 - 10 of 15622 matches for " Bruno; Moreira "
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Tanned or Burned: The Role of Fire in Shaping Physical Seed Dormancy
Bruno Moreira, Juli G. Pausas
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0051523
Abstract: Plant species with physical seed dormancy are common in mediterranean fire-prone ecosystems. Because fire breaks seed dormancy and enhances the recruitment of many species, this trait might be considered adaptive in fire-prone environments. However, to what extent the temperature thresholds that break physical seed dormancy have been shaped by fire (i.e., for post-fire recruitment) or by summer temperatures in the bare soil (i.e., for recruitment in fire-independent gaps) remains unknown. Our hypothesis is that the temperature thresholds that break physical seed dormancy have been shaped by fire and thus we predict higher dormancy lost in response to fire than in response to summer temperatures. We tested this hypothesis in six woody species with physical seed dormancy occurring in fire-prone areas across the Mediterranean Basin. Seeds from different populations of each species were subject to heat treatments simulating fire (i.e., a single high temperature peak of 100°C, 120°C or 150°C for 5 minutes) and heat treatments simulating summer (i.e., temperature fluctuations; 30 daily cycles of 3 hours at 31°C, 4 hours at 43°C, 3 hours at 33°C and 14 hours at 18°C). Fire treatments broke dormancy and stimulated germination in all populations of all species. In contrast, summer treatments had no effect over the seed dormancy for most species and only enhanced the germination in Ulex parviflorus, although less than the fire treatments. Our results suggest that in Mediterranean species with physical dormancy, the temperature thresholds necessary to trigger seed germination are better explained as a response to fire than as a response to summer temperatures. The high level of dormancy release by the heat produced by fire might enforce most recruitment to be capitalized into a single post-fire pulse when the most favorable conditions occur. This supports the important role of fire in shaping seed traits.
Protein disorder in plants: a view from the chloroplast
Inmaculada Yruela, Bruno Contreras-Moreira
BMC Plant Biology , 2012, DOI: 10.1186/1471-2229-12-165
Abstract: Our analysis of plant genomes confirms that nuclear-encoded proteins follow the same trend than other multi-cellular eukaryotes; however, chloroplast- and mitochondria- encoded proteins conserve the patterns of Archaea and Bacteria, in agreement with their phylogenetic origin. Based on current knowledge about gene transference from the chloroplast to the nucleus, we report a strong correlation between the rate of disorder of transferred and nuclear-encoded proteins, even for polypeptides that play functional roles back in the chloroplast. We further investigate this trend by reviewing the set of chloroplast ribosomal proteins, one of the most representative transferred gene clusters, finding that the ribosomal large subunit, assembled from a majority of nuclear-encoded proteins, is clearly more unstructured than the small one, which integrates mostly plastid-encoded proteins.Our observations suggest that the evolutionary dynamics of the plant nucleus adds disordered segments to genes alike, regardless of their origin, with the notable exception of proteins currently encoded in both genomes, probably due to functional constraints.A relevant fraction of genomes encode for proteins with structural disordered regions. Intrinsically protein disorder refers to segments or to whole proteins that do not fold into well-defined regular three-dimensional structures in isolation (i.e. not bound to other molecules) [1,2]. This disorder covers local flexible loops, extended domains, molten globule domains and folded domains with flexible linkers [3]. Thus, proteins might be either entirely disordered or partially disordered, characterised by regions spanning just a few (<10) consecutive disordered residues (loops in otherwise well-structured proteins) or long stretches (>30) of contiguously disordered residues. The presence of protein disorder is thought to confer dynamic flexibility to proteins, allowing transitions between different structural states [4]. This increased flexibi
Learning to Rank for Expert Search in Digital Libraries of Academic Publications
Catarina Moreira,Pável Calado,Bruno Martins
Computer Science , 2013,
Abstract: The task of expert finding has been getting increasing attention in information retrieval literature. However, the current state-of-the-art is still lacking in principled approaches for combining different sources of evidence in an optimal way. This paper explores the usage of learning to rank methods as a principled approach for combining multiple estimators of expertise, derived from the textual contents, from the graph-structure with the citation patterns for the community of experts, and from profile information about the experts. Experiments made over a dataset of academic publications, for the area of Computer Science, attest for the adequacy of the proposed approaches.
Using Rank Aggregation for Expert Search in Academic Digital Libraries
Catarina Moreira,Bruno Martins,Pável Calado
Computer Science , 2015,
Abstract: The task of expert finding has been getting increasing attention in information retrieval literature. However, the current state-of-the-art is still lacking in principled approaches for combining different sources of evidence. This paper explores the usage of unsupervised rank aggregation methods as a principled approach for combining multiple estimators of expertise, derived from the textual contents, from the graph-structure of the citation patterns for the community of experts, and from profile information about the experts. We specifically experimented two unsupervised rank aggregation approaches well known in the information retrieval literature, namely CombSUM and CombMNZ. Experiments made over a dataset of academic publications for the area of Computer Science attest for the adequacy of these methods.
Learning to Rank Academic Experts in the DBLP Dataset
Catarina Moreira,Bruno Martins,Pável Calado
Computer Science , 2015, DOI: 10.1111/exsy.12062
Abstract: Expert finding is an information retrieval task that is concerned with the search for the most knowledgeable people with respect to a specific topic, and the search is based on documents that describe people's activities. The task involves taking a user query as input and returning a list of people who are sorted by their level of expertise with respect to the user query. Despite recent interest in the area, the current state-of-the-art techniques lack in principled approaches for optimally combining different sources of evidence. This article proposes two frameworks for combining multiple estimators of expertise. These estimators are derived from textual contents, from graph-structure of the citation patterns for the community of experts, and from profile information about the experts. More specifically, this article explores the use of supervised learning to rank methods, as well as rank aggregation approaches, for combing all of the estimators of expertise. Several supervised learning algorithms, which are representative of the pointwise, pairwise and listwise approaches, were tested, and various state-of-the-art data fusion techniques were also explored for the rank aggregation framework. Experiments that were performed on a dataset of academic publications from the Computer Science domain attest the adequacy of the proposed approaches.
The Use of Solid State NMR to Evaluate the Carbohydrates in Commercial Coffee Granules  [PDF]
Regina Freitas Nogueira, Elisangela Fabiana Boffo, Maria Inês Bruno Tavares, Leonardo A. Moreira, Leila Aley Tavares, Ant?nio Gilberto Ferreira
Food and Nutrition Sciences (FNS) , 2011, DOI: 10.4236/fns.2011.24050
Abstract: Coffee brings many health benefits due to its chemical constituents. Based on this information, it is essential to know the main chemical compounds from coffee granules; the intermolecular interaction among the coffees compounds and the molecular components homogeneity. In this study six types of roasted commercial coffee were evaluated by solid state nuclear magnetic resonance (NMR), employing carbon-13 (13C) and hydrogen (1H) nucleus. Carbon-13 was analyzed applying high field NMR techniques, such as: magic angle spinning (MAS); magic angle spinning with cross-polariza- tion (CPMAS) and magic angle spinning with cross-polarization and dipolar dephasing (CPMASDD). The hydrogen was evaluated via relaxation times. Proton spin-lattice relaxation time in the rotating frame was deter-mined through the carbon-13 decay, during the variable contact-time experiment, using high field NMR. Proton spin-lattice relaxation time was determined through the inversion-recovery pulse sequence, using low field NMR. Considering all NMR results, it was concluded that the major coffee compounds are: a) triacilglycerides, which constitute the mobile region in the granule coffee and b) Carbohydrates such as: polysaccharides and fibers that belong to the rigid domain. These constituents belong to different molecular mobility domain, although they have strong intermolecular interactions due to the granule organization.
Da Classifica??o de Viena para a Nova Classifica??o de Montreal: Caracteriza??o Fenotípica e Evolu??o Clínica da Doen?a de Crohn
Rebelo,Ana; Rosa,Bruno; Moreira,Maria Jo?o; Cotter,José;
Jornal Português de Gastrenterologia , 2011,
Abstract: montreal classification (mc) succeeded vienna classification (vc) in the characterization of patients with crohn′s disease (cd). in order to evaluate the differences and potential advantages of the first regarding the last one and validate the mc through the longitudinal analysis of the phenotypic variation of this population, 122 crohn′s patients were retrospectively analyzed and classified according to both classifications. the evolution of both subgroups and the need for surgery was analysed. results showed that mc reclassified 6 patients in the criteria age at diagnosis (a), 4 in the criteria location (l) and 18 in the criteria behaviour (b). the disease location (l) remained stable. the behaviour (b) by the vc classification changed at 3 and 5 years. 41,8% of patients underwent major surgery. a higher association between the need for surgery and the group b3 of mc was identified. there were no statistically significant differences between the survival curves and sex, smoking and age at diagnosis. conclusion: the mc is more sensitive in the phenotypic evaluation of behaviour of cd, especially after exclusion of perianal disease from the category penetrating disease. the classification of cd by phenotypic pattern could possibly, in future, be applied to predict its natural history.
Enteroscopia por cápsula na suspeita de doen?a de Crohn: há lugar para o Score de Lewis na prática clínica?
Rosa,Bruno; Moreira,Maria Jo?o; Rebelo,Ana; Cotter,José;
Jornal Português de Gastrenterologia , 2010,
Abstract: introduction: suspected crohn?s disease (cd) is a common indication for capsule enteroscopy (ce). however, lesions are nonspecific and no gold standard is available for diagnosing cd. lewis score (ls) measures inflammatory activity based on oedematous villous appearance, ulcers and stenoses. aim: to evaluate the role of sl in the diagnosis of cd in clinical practice. methods: thirty patients who underwent ce for suspected cd were included and followed up for at least six months. inflammatory activity was classified in three levels: clinically insignificant (score<135), mild (135≤score≤790) or moderate to severe (score > 790). results: diagnosis of cd was established in 10 patients (33%). clinically significant inflammatory activity (score ≥ 135) had a positive predictive value (vpp) = 75%, negative predictive value (vpn) = 94%, sensitivity (s) = 90% and specificity (e) = 85% for the diagnosis of cd. conclusions: ls seems to be a useful index in the setting of suspected cd, increasing the objectivity of ce findings; it also has a good correlation with the diagnosis established during follow-up.
Nutritional status is related to fat-free mass, exercise capacity and inspiratory strength in severe chronic obstructive pulmonary disease patients
Sabino, Pollyane Galinari;Silva, Bruno Moreira;Brunetto, Antonio Fernando;
Clinics , 2010, DOI: 10.1590/S1807-59322010000600007
Abstract: introduction: being overweight or obese is associated with a higher rate of survival in patients with advanced chronic obstructive pulmonary disease (copd). this paradoxical relationship indicates that the influence of nutritional status on functional parameters should be further investigated. objective: to investigate the impact of nutritional status on body composition, exercise capacity and respiratory muscle strength in severe chronic obstructive pulmonary disease patients. methods: thirty-two patients (nine women) were divided into three groups according to their body mass indices (bmi): overweight/obese (25 < bmi < 34.9 kg/m2, n=8), normal weight (18.5 < bmi < 24.9 kg/m2, n=17) and underweight (bmi <18.5 kg/m2, n=7). spirometry, bioelectrical impedance, a six-minute walking distance test and maximal inspiratory and expiratory pressures were assessed. results: airway obstruction was similar among the groups (p=0.30); however, overweight/obese patients had a higher fat-free mass (ffm) index [ffmi=ffm/body weight2 (mean±sem: 17±0.3 vs. 15±0.3 vs. 14±0.5 m/kg2, p<0.01)], exercise capacity (90±8 vs. 79±6 vs. 57±8 m, p=0.02) and maximal inspiratory pressure (63±7 vs. 57±5 vs. 35±8 % predicted, p=0.03) in comparison to normal weight and underweight patients, respectively. in addition, on backward multiple regression analysis, ffmi was the unique independent predictor of exercise capacity (partial r=0.52, p<0.01). conclusions: severe chronic obstructive pulmonary disease (copd) patients who were overweight or obese had a greater ffm, exercise capacity and inspiratory muscle strength than patients with the same degree of airflow obstruction who were of normal weight or underweight, and higher ffm was independently associated with higher exercise capacity. these characteristics of overweight or obese patients might counteract the drawbacks of excess weight and lead to an improved prognosis in copd.
Efeitos do pós-condicionamento isquêmico na fun??o ventricular esquerda de cora??es isolados de ratos
Pinheiro, Bruno Botelho;Fiorelli, Alfredo Inácio;Gomes, Otoni Moreira;
Revista Brasileira de Cirurgia Cardiovascular , 2009, DOI: 10.1590/S0102-76382009000100007
Abstract: objective: to assess the effects of ischemic postconditioning on left ventricular function in isolated rat hearts. methods: twenty-four wistar rats were used. these hearts underwent perfusion by modified langerdorff method and distributed into three groups: gi - control (n=8); gii - three cycles of postconditioning of 10/10s (n=8); giii three cycles of postconditioning of 30/30s (n=8). after a 15min stabilization period, all hearts underwent 20min of global ischemia following 20min of reperfusion. in the times 0 (control), 5, 10, 15 and 20min of reperfusion, the heart rate (hr), the coronary flow (cof), the systolic pressure, the (+dp/dt max) contractility and (-dp/dt max) velocity of relaxation were measured. data were analyzed by anova method followed by tukey's test for differences between groups and p < 0.05 was considered significant. results: the hr (bpm) decreased in all groups after 20min of reperfusion without statistical differences among them (gi 232.5+36.8; gii 241.8+46.7; giii 249.4+40.4;p>0.05). the same occurred with the systolic pressure (mmhg) (gi 132.6+49.3; gii 140.8+43.1; giii 112.6+33.2; p>0.05), coronary blood flow (gi 18.5+4.6; gii 21.4+4.4; giii 22.1+9.0; p>0.05) and -dp/dt max (mmhg) (gi 1490.6+512.0; gii 1770.4+406.6; giii 1399.1+327.4; p>0.05). the +dp/dt max (mmhg) decreased significantly in all groups except in group ii (gi 1409.0+415.2, gii 1917.3+403.1, giii 1344.8+355.8) (gii vs gi, p= 0.04; gii vs giii, p= 0.02). conclusion: the ischemic postconditioning by three cycles of reperfusion/ischemia of 10/10s demonstrated to be effective for preservation of the myocardial contractility in isolated rat hearts which had undergone 20min of ischemia.
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