324 research outputs found

    Dynamics of Quality Perception in a Social Network: A Cellular Automaton Based Model in Aesthetics Services

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    AbstractAn attempt was carried out to simulate interactions between customers and providers, and understand the rationality of a social network using a cellular automata model. A longitudinal research study was conducted, based on a dyadic perspective in aesthetics clinics, approaching clients and service providers. The evolution of opinions regarding the associated service quality was then modeled with a cellular automaton. Based on an existing and valid scale of service quality, six semi-structured interviews with clients and service providers were carried out. The indicators were then refined and two quantitative surveys were performed, with a time interval of four months. A cellular automaton rule was then searched for that could simulate the network rationality between the two surveys. The proposed cellular automaton model achieved an accuracy of 73.80%, a higher value than the ones typically found in linear regression models of the service quality literature. The simulation allowed to understand which behaviours adopted by providers and customers generate an improved perception of service quality. The simulation also identified dissatisfied individuals in the social network and the way they influence the network. These findings may help managers to control employees' conducts and the service performance

    A universal approach for drainage basins

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    Drainage basins are essential to Geohydrology and Biodiversity. Defining those regions in a simple, robust and efficient way is a constant challenge in Earth Science. Here, we introduce a model to delineate multiple drainage basins through an extension of the Invasion Percolation-Based Algorithm (IPBA). In order to prove the potential of our approach, we apply it to real and artificial datasets. We observe that the perimeter and area distributions of basins and anti-basins display long tails extending over several orders of magnitude and following approximately power-law behaviors. Moreover, the exponents of these power laws depend on spatial correlations and are invariant under the landscape orientation, not only for terrestrial, but lunar and martian landscapes. The terrestrial and martian results are statistically identical, which suggests that a hypothetical martian river would present similarity to the terrestrial rivers. Finally, we propose a theoretical value for the Hack's exponent based on the fractal dimension of watersheds, γ=D/2\gamma=D/2. We measure γ=0.54±0.01\gamma=0.54 \pm 0.01 for Earth, which is close to our estimation of γ≈0.55\gamma \approx 0.55. Our study suggests that Hack's law can have its origin purely in the maximum and minimum lines of the landscapes.Comment: 20 pages, 6 Figures, and 1 Tabl

    Comparação da prova de função pulmonar e da força muscular respiratória entre idosas osteoporóticas com e sem fratura vertebral torácica = Comparation of pulmonary function and respiratory muscle strength among older osteoporotic women with and without thoracic vertebral fracture

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    Introduction: Osteoporosis is a disease characterized by decreased bone mass, resulting in fractures, which may occur in the thoracic vertebrae, causing changes in respiratory mechanics, impairing lung function. Objectives: To compare the spirometric, respiratory muscle strength and angle of thoracic kyphosis among elderly osteoporotic vertebral fractures with and without chest. Methods: The sample was divided into group A, elderly women with thoracic vertebral fracture (n = 5) and group B, older chest without vertebral fracture (n = 7). All were assessed by spirometry, manometer, and anthropometric measurements of the thoracic curvature. Results: The results showed an increase in thoracic curvature and a decrease in lung function in Group A compared with Group B and respiratory muscle strength deficit in Group A. Conclusion: The thoracic kyphosis deformity, caused by osteoporotic fractures, affects both the respiratory and musculoskeletal system

    Fatores de risco para a transmissao vertical do HIV-1 e a influencia da terapia antirretroviral (ARV) no desfecho gestacional

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    In the absence of intervention, the rate of vertical transmission of HIV can range from 15-45%. With the inclusion of antiretroviral drugs during pregnancy and the choice of delivery route this amounts to less than 2%. However ARV use during pregnancy has generated several questions regarding the adverse effects of the gestational and neonatal outcome. This study aims to analyze the risk factors for vertical transmission of HIV-1 seropositive pregnant women living in Rio Grande and the influence of the use of ARVs in pregnancy outcome. Among the 262 pregnant women studied the rate of vertical transmission of HIV was found to be 3.8%. Regarding the VT, there was a lower risk of transmission when antiretroviral drugs were used and prenatal care was conducted at the referral service. However, the use of ART did not influence the outcome of pregnancy. However, initiation of prenatal care after the first trimester had an influence on low birth weight, as well as performance of less than six visits increased the risk of prematurity. Therefore, the risk factors analyzed in this study appear to be related to the realization of inadequate pre-natal and maternal behavior.Na ausência de intervenção, as taxas de transmissão vertical do HIV podem variar de 15-45%. Com a inserção dos antirretrovirais durante a gestação e a escolha da via de parto estas taxas chegam a menos de 2%. No entanto o uso de ARV na gestação tem gerado várias duvidas quanto aos efeitos adversos causados ao desfecho gestacional e ao neonato. Este estudo objetiva analisar os fatores de risco da transmissão vertical do HIV-1 em gestantes soropositivas atendidas na cidade do Rio Grande e a influência do uso do ARV no desfecho gestacional. Entre as 262 gestantes estudadas a taxa de transmissão vertical do HIV encontrada foi de 3,8%. Em relação à TV, foi observado menor risco de transmissão quando esta havia feito uso de antirretrovirais e o pré-natal era realizado no serviço de referência. Entretanto, o uso de ARV não influenciou negativamente o desfecho gestacional. No entanto, o inicio do pré-natal após o primeiro trimestre teve influencia sobre o baixo peso ao nascer, assim como a realização de menos de seis consultas aumentou o risco de prematuridade. Portanto, os fatores de risco analisados neste estudo parecem estar relacionados à realização não adequada do pré-natal e ao comportamento materno

    Mitigation of nitrous oxide emissions in grazing systems through nitrification inhibitors: a meta-analysis

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    Grasslands are the largest contributor of nitrous oxide (N2O) emissions in the agriculture sector due to livestock excreta and nitrogen fertilizers applied to the soil. Nitrification inhibitors (NIs) added to N input have reduced N2O emissions, but can show a range of efficiencies depending on climate, soil, and management conditions. A meta-analysis study was conducted to investigate the factors that influence the efficiency of NIs added to fertilizer and excreta in reducing N2O emissions, focused on grazing systems. Data from peer-reviewed studies comprising 2164 N2O emission factors (EFs) of N inputs with and without NIs addition were compared. The N2O EFs varied according to N source (0.0001-8.25%). Overall, NIs reduced the N2O EF from N addition by 56.6% (51.1-61.5%), with no difference between NI types (Dicyandiamide-DCD; 3,4-Dimethylpyrazole phosphate-DMPP; and Nitrapyrin) or N source (urine, dung, slurry, and fertilizer). The NIs were more efficient in situations of high N2O emissions compared with low; the reduction was 66.0% when EF > 1.5% of N applied compared with 51.9% when EF 10 kg ha(-1). NIs were less efficient in urine with lower N content (<= 7 g kg(-1)). NI efficiency was negatively correlated with soil bulk density, and positively correlated with soil moisture and temperature. Better understanding and management of NIs can optimize N2O mitigation in grazing systems, e.g., by mapping N2O risk and applying NI at variable rate, contributing to improved livestock sustainability

    Can intraoperative electrocorticography patterns predict surgical outcome in patients with temporal lobe epilepsy secondary to unilateral mesial temporal sclerosis?

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    Introduction: Intraoperative electrocorticography (ECoG) can be performed in cases of temporal lobe epilepsy due to hippocampal sclerosis (TLE-HS). However, its significance and correlation with surgical outcome are still controversial.Objectives: To analyze the electrophysiological characteristics of temporal lobe structures during ECoG of patients with TLE-HS, with emphasis on the comparison between pre- and post-resection recordings and surgical outcome.Patients and methods: Seventeen patients with refractory TLE-HS submitted to corticoamigdalohipocampectomy were included in the study. Clinical variables included age at the onset, duration of epilepsy and seizure outcome. the postoperative follow-up ranged from 24 to 36 months. According to outcome subjects were divided in two subgroups: (A) individuals free of seizures (Engel 1A), and (B) individuals not-free of seizures (Engel 1B-IV). Four patterns of ECoG findings were identified: isolated discharges; high frequency spikes (HFS); continuous discharges; combination of isolated discharges and HFS. According to predominant topography ECoG was classified as mediobasal, lateral (or neocortical), mediobasal and lateral.Results: the progressive removal of the temporal pole and the hippocampus was associated with significant decrease of neocortical spikes. No correlation between clinical variables and seizure outcome was observed. Patients who only had isolated spikes on intraoperative ECoG presented a statistical trend for excellent surgical control. Patients who presented temporal pole blurring on MRI also had better post-surgical seizure outcome.Conclusions: This study showed that out of diverse clinical and laboratory variables, only isolated discharges on intraoperative ECoG and temporal pole blurring on MRI predicted excellent post-surgicat seizure outcome. However, other studies with larger number of patients are stilt necessary to confirm these findings. (C) 2006 British Epilepsy Association. Published by Elsevier B.V. All rights reserved.Universidade Federal de São Paulo, Dept Neurol & Neurosurg, Div Neurol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Radiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Neurol & Neurosurg, Div Neurosurg, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Anesthesiol, São Paulo, BrazilUniv São Paulo, Ribeirao Preto Med Sch, Dept Surg, Div Neurosurg, São Paulo, BrazilUniv São Paulo, Ribeirao Preto Med Sch, Dept Neurol Psychiat & Clin Psychol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Neurol & Neurosurg, Div Neurol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Radiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Neurol & Neurosurg, Div Neurosurg, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Anesthesiol, São Paulo, BrazilWeb of Scienc

    Taekwondo athletes have better postural control than handball and american football athletes / Atletas de taekwondon têm melhor controle postural do que atletas de handebol e futebol americano

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    Introduction: Postural control is an important prerequisite for an athlete’s performance in sport. In addition, the postural control system contributes to injury prevention. Deficits in this system can lead to body instability and overload of musculoskeletal structures generating dysfunction and pain. Objectives: The purpose of this study was to evaluate postural control in three different sports modalities: taekwondo, handball, and American football. Methods: All athletes performed a one-legged stance/balance test on a force platform in the right and left lower limbs. Three tests of thirty seconds each were performed with eyes open. The mean of the three tests was used to measure the parameters of postural control, pressure center and velocity of anteroposterior and mediolateral displacements. Results: Significant differences were observed among the three groups in all analyzed parameters (P=<0.04). Post-hoc analysis revealed that taekwondo athletes had better postural control (P=<0.035) of lower limbs compared to the other two modalities. There were no significant differences between handball and American football. Conclusion: Taekwondo athletes have better postural control during the one-legged stance/balance test than handball and American football athletes. Introdução: O controle postural é um pré-requisito importante para o desempenho do atleta no esporte. Além disso, o sistema de controle postural contribui para a prevenção de lesões. Déficits nesse sistema podem levar a instabilidade corporal e sobrecarga das estruturas musculoesqueléticas, gerando disfunção e dor. Objetivos: A proposta deste estudo foi avaliar o controle postural em três diferentes modalidades esportivas: taekwondo, handebol e futebol americano. Métodos: Todos os atletas executaram o teste de equilíbrio unipodal sobre uma plataforma de força nos membros inferiores direito e esquerdo. Foram realizados três testes de trinta segundos cada, com os olhos abertos. A média dos três testes foi utilizada para mensurar os parâmetros de controle postural, centro de pressão e velocidade dos deslocamentos anteroposteriores e mediolaterais. Resultados: Diferenças significativas foram observadas entre os três grupos em todos os parâmetros analisados (P = <0,04). A análise post hoc revelou que os atletas de taekwondo tiveram melhor controle postural (P = < 0,035) dos membros inferiores em comparação com as outras duas modalidades. Não foram observadas diferenças significativas entre o handebol e o futebol americano. Conclusão: Os atletas do taekwondo têm melhor controle postural durante o teste de equilíbrio unipodal do que os atletas do handebol e do futebol americano
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