501 research outputs found
Torqued fireballs in relativistic heavy-ion collisions
We show that the fluctuations in the wounded-nucleon model of the initial
stage of relativistic heavy-ion collisions, together with the natural
assumption that the forward (backward) moving wounded nucleons emit particles
preferably in the forward (backward) direction, lead to an event-by-event
torqued fireball. The principal axes associated with the transverse shape are
rotated in the forward region in the opposite direction than in the backward
region. On the average, the standard deviation of the relative torque angle
between the forward and backward rapidity regions is about 20deg for the
central and 10deg for the mid-peripheral collisions. The hydrodynamic expansion
of a torqued fireball leads to a torqued collective flow, yielding, in turn,
torqued principal axes of the transverse-momentum distributions at different
rapidities. We propose experimental measures, based on cumulants involving
particles in different rapidity regions, which should allow for a quantitative
determination of the effect from the data. To estimate the non-flow
contributions from resonance decays we run Monte Carlo simulations with
THERMINATOR. If the event-by-event torque effect is found in the data, it will
support the assumptions concerning the fluctuations in the early stage of the
fireball formation, as well as the hypothesis of the asymmetric rapidity shape
of the emission functions of the moving sources in the nucleus-nucleus
collisions.Comment: Grant reference adde
Potential for technological modernisation and innovation based on ICT in agri-food companies of central region of Portugal
This paper assesses the potential for technological modernisation and innovation based on Information and Communication Technologies (ICT) in agri-food companies located in the central region of Portugal. The survey was applied to 50 agri-food companies of Cereals, Cheese, Olive oil, Dry sausages, Honey, Wine, and Horticultural sectors. Survey results can be summarised as: The large majority of companies use computers and have Internet service. Most of companies don't have a webpage and neither use Internet for advertising campaigns, selling or buying products. Half of companies use social networks for business purposes. Most companies haven't promoted collaborators training in ICT in the last year. Companies claim that possessing a webpage and attending ICT training will be the technological solutions that will improve their productivity and/or marketing products and services. For each sector, recommendations and suggestions were provided in order to promote the use of ICT for business purposes.info:eu-repo/semantics/publishedVersio
new considerations on substrate inhibition profile and catalytic mechanism
We would like to thank Fundacao para a Ciencia e Tecnologia for the financial support through grants SFRH/BD/39009/2007 (AGD), PDTC/QUI/64638/2006 (IM) and PDCT/QUI-BIOQ/1/6481/2010 (IM). REQUIMTE is funded by grant PEst-C/EQB/LA0006/2013 from FCT/MEC.Nitric oxide reductase (NOR) from denitrifying bacteria is an integral membrane protein that catalyses the two electron reduction of NO to N2O, as part of the denitrification process, being responsible for an exclusive reaction, the NN bond formation, the key step of this metabolic pathway. Additionally, this class of enzymes also presents residual oxidoreductase activity, reducing O2 to H2O in a four electron/proton reaction. In this work we report, for the first time, steady-state kinetics with the Pseudomonas nautica NOR, either in the presence of its physiological electron donor (cyt. c552) or immobilised on a graphite electrode surface, in the presence of its known substrates, namely NO or O2. The obtained results show that the enzyme has high affinity for its natural substrate, NO, and different kinetic profiles according to the electron donor used. The kinetic data, as shown by the pH dependence, is modelled by ionisable amino acid residues nearby the di-nuclear catalytic site. The catalytic mechanism is revised and a mononitrosyl-non-heme Fe complex (FeB(II)-NO) species is favoured as the first catalytic intermediate involved on the NO reduction.publishersversionpublishe
Práticas formativas em psicologia social, do trabalho e das organizações: análises de campo e propostas de plano de ação
Retinal OCT speckle as a biomarker for glaucoma diagnosis and staging
This paper presents a novel image analysis strategy that increases the potential of macular Optical Coherence Tomography (OCT) by using speckle features as biomarkers in different stages of glaucoma. A large pool of features (480) were computed for a subset of macular OCT volumes of the Leuven eye study cohort. The dataset contained 258 subjects that were divided into four groups based on their glaucoma severity: Healthy (56), Mild (94), Moderate (48), and Severe (60). The OCT speckle features were categorized as statistical properties, statistical distributions, contrast, spatial gray-level dependence matrices, and frequency domain features. The averaged thicknesses of ten retinal layers were also collected. Kruskal-Wallis H test and multivariable regression models were used to infer the most significant features related to glaucoma severity classification and to the correlation with visual field mean deviation. Four features were selected as being the most relevant: the ganglion cell layer (GCL) and the inner plexiform layer (IPL) thicknesses, and two OCT speckle features, the data skewness computed on the retinal nerve fiber layer (RNFL) and the scale parameter (a) of the generalized gamma distribution fitted to the GCL data. Based on a significance level of 0.05, the regression models revealed that RNFL skewness exhibited the highest significance among the features considered for glaucoma severity staging (p-values of 8.6×10-6 for the logistic model and 2.8×10-7 for the linear model). Furthermore, it demonstrated a strong negative correlation with the visual field mean deviation (ρ=-0.64). The post hoc analysis revealed that, when distinguishing healthy controls from glaucoma subjects, GCL thickness is the most relevant feature (p-value of 8.7×10-5). Conversely, when comparing the Mild versus Moderate stages of glaucoma, RNFL skewness emerged as the only feature exhibiting statistical significance (p-value = 0.001). This work shows that macular OCT speckle contains information that is currently not used in clinical practice, and not only complements structural measurements (thickness) but also has a potential for glaucoma staging
Determinação não destrutiva do nitrogênio total em plantas por espectroscopia de reflectância difusa no infravermelho próximo
Diffuse reflectance near-infrared (DR-NIR) spectroscopy associated with partial least squares (PLS) multivariate calibration is proposed for a direct, non-destructive, determination of total nitrogen in wheat leaves. The procedure was developed for an Analytical Instrumental Analysis course, carried out at the Institute of Chemistry of the State University of Campinas. The DR-NIR results are in good agreement with those obtained by the Kjeldhal standard procedure, with a relative error of less than ± 3% and the method may be used for teaching purposes as well as for routine analysis
Forage Intake and Nitrogen Retention in Wethers Fed Ryegrass Haylage Supplemented with Maize Silage
Many decision support tools have been developed to predict herbage intake with herbivore ruminants indoors (Faverdin 1992) or at grazing, both using short-term (Baumont et al. 2004) or daily scale input variables (Heard et al. 2004; Delagarde et al. 2011). However, the ingestive and digestive interactions when diets with more than one type of forage are used have not been sufficiently studied. The aim of this study was to assess the effects of maize silage supplementation to wethers receiving ryegrass haylage on OM intake, OM digestibility, microbial protein synthesis and N retention
Anéis vasculares na infância: diagnóstico e tratamento
Objetivo: apresentar a experiência do Serviço de Cirurgia Pediátrica do Instituto da Criança do HCFMUSP no diagnóstico e tratamento de crianças com anomalias do arco aórtico e definir a importância dos exames complementares para o diagnóstico. Métodos: estudo retrospectivo de 22 crianças com diagnóstico de compressão traqueoesofágica por anel vascular tratadas no Instituto da Criança, no período de 1985 a 2000, investigando-se dados clínicos pré e pós-operatórios, exames complementares e evolução. Resultados: a anomalia vascular mais freqüente foi artéria inominada direita anômala (10 casos), seguido de duplo arco aórtico (7 casos) e arco aórtico à direita (5 casos). Os sintomas predominantes foram respiratórios (86%) e de início precoce (76% desde o período neonatal). Entretanto, o diagnóstico definitivo na maioria dos casos (60%) só foi estabelecido após 1 ano de vida. O exame mais importante para o diagnóstico foi o esofagograma. A correção de todas anomalias foi realizada por toracotomia póstero-lateral esquerda. Não ocorreram complicações cirúrgicas. A evolução foi pior nos casos operados mais tardiamente. Todas as crianças permaneceram sintomáticas por até 6 meses, apesar de significativa melhora no pós-operatório. Conclusão: o diagnóstico de anel vascular deve ser investigado nas crianças com sintomas respiratórios de início precoce e nas "chiadoras" de difícil controle. O diagnóstico pode ser realizado de forma simples através do esofagograma. Os demais exames de imagem acrescentam poucas informações e são dispensáveis na maioria dos casos. Os sintomas respiratórios podem persistir com menor intensidade por períodos variáveis no pós-operatório.<br>Objective: To present the study carried out by the Pediatric Surgery Department of Instituto da Criança at the Medical School of Universidade de São Paulo regarding the diagnosis and treatment of children with aortic arch abnormalities and to define the role of complementary exams for diagnosis. Methods: Retrospective study of 22 patients with diagnosis of tracheoesophageal compression treated at Instituto da Criança from 1985 to 2000, analyzing pre- and postoperative clinical data, diagnostic exams and outcome. Results: The most frequent diagnosis was right aberrant innominate artery (10 cases), followed by double aortic arch (7 cases) and right aortic arch (5 cases). Respiratory symptoms (86%) and early manifestation (76% since the neonatal period) were predominant. Nevertheless, most cases (60%) had the definitive diagnosis established only after 1 year of life. The most relevant examination for the diagnosis was the esophagogram. The correction of all the anomalies was carried out through left postero-lateral thoracotomy. There were no surgical complications. The outcome was worse in patients with delayed treatment. All children remained symptomatic for up to 6 months, although they had significant improvement in the postoperative period. Conclusions: The diagnosis of vascular rings should be considered in children with early respiratory symptoms and in the wheezing baby with difficult control. The diagnosis may be established just through the esophagogram. Other image studies add few information and they are unnecessary in most cases. Less severe symptoms may persist for variable periods
Network-based data classification: combining k-associated optimal graphs and high-level prediction
Background: Traditional data classification techniques usually divide the data space into sub-spaces, each representing a class. Such a division is carried out considering only physical attributes of the training data (e.g., distance, similarity, or distribution). This approach is called low-level classification. On the other hand, network or graph-based approach is able to capture spacial, functional, and topological relations among data, providing a so-called high-level classification. Usually, network-based algorithms consist of two steps: network construction and classification. Despite that complex network measures are employed in the classification to capture patterns of the input data, the network formation step is critical and is not well explored. Some of them, such as K-nearest neighbors algorithm (KNN) and -radius, consider strict local information of the data and, moreover, depend on some parameters, which are not easy to be set. \ud
Methods: We propose a network-based classification technique, named high-level classification on K-associated optimal graph (HL-KAOG), combining the K-associated optimal graph and high-level prediction. In this way, the network construction algorithm is non-parametric, and it considers both local and global information of the training data. In addition, since the proposed technique combines low-level and high-level terms, it classifies data not only by physical features but also by checking conformation of the test instance to formation pattern of each class component. Computer simulations are conducted to assess the effectiveness of the proposed technique.\ud
Results: The results show that a larger portion of the high-level term is required to get correct classification when there is a complex-formed and well-defined pattern in the data set. In this case, we also show that traditional classification algorithms are unable to identify those data patterns. Moreover, computer simulations on real-world data sets show that HL-KAOG and support vector machines provide similar results and they outperform well-known techniques, such as decision trees and K-nearest neighbors. \ud
Conclusions: The proposed technique works with a very reduced number of parameters and it is able to obtain good predictive performance in comparison with traditional techniques. In addition, the combination of high level and low level algorithms based on network components can allow greater exploration of patterns in data sets.São Paulo State Research Foundation (FAPESP)Brazilian National Council for Scientific and Technological Development (CNPq
Herbage Intake, Methane Emissions and Animal Performance of Steers Grazing Dwarf Elephant Grass with or without Access to \u3cem\u3eArachis pintoi\u3c/em\u3e Pastures
The inclusion of legumes in diets based on grass has nutritional benefits due to ingestive and digestive interactions (Niderkorn and Baumont 2009). Moreover, it is speculated that tropical legumes can contribute to reducing the emission of greenhouse gases (GHG) compared to diets exclusively composed of grasses (Archimède et al. 2011). However, under grazing conditions, these advantages are not always possible to obtain. This occurs when the spatial distribution of sward grasses impose limitations on access to legumes by grazing animals (Solomon et al. 2011). This can be the case, for example, when legumes are overlapped by the leaves of a tufted tall grass, as dwarf elephant grass (Crestani et al. 2013).
Considering that management strategies for increasing legumes in the diet of grazing animals should be better studied and data on enteric methane emitted by ruminants eating tropical forages are scarce, the aim of this work was to evaluate the effect of access to an exclusive area of peanuts (Arachis pintoi cv. Amarillo) for cattle grazing dwarf elephant grass (Pennisetum purpureum cv. BRS Kurumi) on herbage intake, animal performance and enteric methane emission
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