935 resultados para Explanatory Variables Effect
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Dyer and McKune (2013) stated that music tempo has no influence on performance, physiological, and psychophysical variables in well-trained cyclists during high intensity endurance tasks. However, there are important limitations in the methodology of the study. The participants'music preferences and tempo change were not well measured. It is not possible to affirm that music tempo does not influence athletes'performance. Potential areas of future research include: (a) use of instruments to assess the qualities of music; (b) standardizing music of tempo according to exercise type (e.g., running, cycling, etc.); (c) considering training level of the participants (i.e., athletes and non-athletes); and (d) use of instruments to assess concentration during exercise.
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Introduction: Our objectives were to determine whether there are changes on the load deflection rate (L/DP) and the average force (FP) of the superelastic pseudoplateau, and whether permanent deformation is changed in nickel-titanium closed-coil springs (CCSs) after 6 months of clinical use. Methods: Twenty-two nickel-titanium CCSs (Sentalloy 100 g; Dentsply GAC, York, Pa) were subjected to tensile mechanical testing at 37 degrees C on activations varying from 3.2 to 16.0 mm before and after 6 months of clinical use. A regression line was fitted over the most horizontal area of the unloading part of the stress-strain graph of every CCS, and its slope was used as L/DP. The FP was determined by the midpoint of the longest segment of the curve that could be fit within the regression line with a R-2 of at least 0.999, and permanent deformation was determined graphically by obtaining the strain value when the measured stress reached zero. The data were analyzed by 3 analyses of variance at 2 levels, with 5% of significance. Results: Time and activation significantly influenced the variables tested (P < 0.001). Time increased the L/DP and permanent deformation but decreased the FP. Activation decreased L/DP, FP, and permanent deformation. Significant interactions between time and activation were detected for FP (P = 0.013) and deformation (P < 0.001). Conclusions: After 6 months of active clinical use, the analyzed springs had a significant but small increase in their L/DP; FP dropped up to 88%, and the CCSs deformed up to 1.26 mm.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Pós-graduação em Ciências da Motricidade - IBRC
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The purpose of this study was to evaluate the impact of different disinfection solutions on flexural resistance of chemically-activated acrylic resin. Test pieces were made of clear acrylic resin using a rectangular mold and employing two techniques: wet polymerization under pressure (n = 20) and dry polymerization under pressure (n = 20). Test pieces were subdivided into four equal groups: distilled water (control), sodium bicarbonate, 1% sodium hypochlorite and effervescent ats. The 30-day cycling technique consisted of immersing the test pieces in 100 ml of solution for 10 min three times a day and placing them in closed containers containing artificial saliva at 37°C. Subsequently, the flexural resistance of samples was tested. Data were analyzed using two-way analysis of variance (ANOVA) with forces serving as the dependent variables and the polymerization technique and cleaning agents as independent variables. Post hoc multiple comparisons were performed using Tukey’s test. There was no statistically significant difference in the flexural strength between the two polymerization techniques. The greatest flexural strength was observed for the effervescent tablets group followed by the control and 1% sodium hypochlorite groups which were statistically similar. Thus, the sodium bicarbonate solution caused the lowest flexural resistance of the test pieces.
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The aim of this study was to evaluate the deformation suffered by cantilevered implant-supported fixed prostheses frameworks cast in silver-palladium alloy and coated with two occlusal veneering materials: acrylic resin or porcelain. Material and Methods: Two strain gauges were bonded to the inferior surface of the silver-palladium framework and two other were bonded to the occlusal surface of the prosthesis framework covered with ceramic and acrylic resin on each of its two halves. The framework was fixed to a metallic master model and a 35.2 N compression force was applied to the cantilever at 10, 15 and 20 mm from the most distal implant. The measurements of deformation by compression and tension were obtained. The statistical 2-way ANOVA test was used for individual analysis of the experiment variables and the Tukey test was used for the interrelation between all the variables (material and distance of force application). Results: The results showed that both variables had influence on the studied factors (deformation by compression and tension). Conclusion: The ceramic coating provided greater rigidity to the assembly and therefore less distortion compared with the uncoated framework and with the resin-coated framework. The cantilever arm length also influenced the prosthesis rigidity, causing higher deformation the farther the load was applied from the last implant.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Unstable shoes have been designed to promote "natural instability" and during walking they should simulate barefoot gait, enhancing muscle activity and, thus, attributing an advantage over regular tennis shoes. Recent studies showed that, after special training on the appropriate walking pattern, the use of the Masai Barefoot Technology (MBT) shoe increases muscle activation during walking. Our study presents a comparison of muscle activity as well as horizontal and vertical forces during gait with the MBT, a standard tennis shoe and barefoot walking of healthy individuals without previous training. These variables were compared in 25 female subjects and gait conditions were compared using ANOVA repeated measures (effect size:0.25). Walking with the MBT shoe in this non-instructed condition produced higher vertical forces (first vertical peak and weight acceptance rate) than walking with a standard shoe or walking barefoot, which suggests an increase in the loads received by the musculoskeletal system, especially at heel strike. Walking with the MBT shoe did not increase muscle activity when compared to walking with the standard shoe. The barefoot condition was more effective than the MBT shoe at enhancing muscle activation. Therefore, in healthy individuals, no advantage was found in using the MBT over a standard tennis shoe without a special training period. Further studies using the MBT without any instruction over a longer period are needed to evaluate if the higher loads observed in the present study would return to their baseline values after a period of adaptation, and if the muscle activity would increase over time. (C) 2012 Elsevier B.V. All rights reserved.
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Effects of roads on wildlife and its habitat have been measured using metrics, such as the nearest road distance, road density, and effective mesh size. In this work we introduce two new indices: (1) Integral Road Effect (IRE), which measured the sum effects of points in a road at a fixed point in the forest; and (2) Average Value of the Infinitesimal Road Effect (AVIRE), which measured the average of the effects of roads at this point. IRE is formally defined as the line integral of a special function (the infinitesimal road effect) along the curves that model the roads, whereas AVIRE is the quotient of IRE by the length of the roads. Combining tools of ArcGIS software with a numerical algorithm, we calculated these and other road and habitat cover indices in a sample of points in a human-modified landscape in the Brazilian Atlantic Forest, where data on the abundance of two groups of small mammals (forest specialists and habitat generalists) were collected in the field. We then compared through the Akaike Information Criterion (AIC) a set of candidate regression models to explain the variation in small mammal abundance, including models with our two new road indices (AVIRE and IRE) or models with other road effect indices (nearest road distance, mesh size, and road density), and reference models (containing only habitat indices, or only the intercept without the effect of any variable). Compared to other road effect indices, AVIRE showed the best performance to explain abundance of forest specialist species, whereas the nearest road distance obtained the best performance to generalist species. AVIRE and habitat together were included in the best model for both small mammal groups, that is, higher abundance of specialist and generalist small mammals occurred where there is lower average road effect (less AVIRE) and more habitat. Moreover, AVIRE was not significantly correlated with habitat cover of specialists and generalists differing from the other road effect indices, except mesh size, which allows for separating the effect of roads from the effect of habitat on small mammal communities. We suggest that the proposed indices and GIS procedures could also be useful to describe other spatial ecological phenomena, such as edge effect in habitat fragments. (C) 2012 Elsevier B.V. All rights reserved.
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Rifampicin, a poorly soluble drug, has great importance in therapeutics as it is the main drug used to treat tuberculosis. The characterization of its permeability and the factors that influence it represent an important tool for predicting its bioavailability. Caco-2 cell monolayers were used as models of the intestinal mucosa to assess the uptake and transport of rifampicin and the effects of various experimental conditions were investigated, in order to establish the influence of these variables on rifampicin permeability. Different pHs (5.8, 6.8 and 7.4) in the apical medium, the presence or absence of mucin (3.0% w/v) in the donor site and the presence or absence of bovine serum albumin (4.0% v/v) in the receptor chamber were the evaluated conditions. The quantification of rifampicin in the apical or basolateral chambers was performed by a validated HPLC-UV method. The change in the donor chamber pH showed that permeability values were greater at pH 6.8, although this increase does not result in an alteration of the qualitative classification of rifampicin, which has high permeability. Mucin and bovine serum showed no effects on the permeability of rifampicin at the concentration tested. Overall, the current study suggests that pH, artificial mucin and bovine serum proteins have no influence on rifampicin permeability. Copyright (c) 2012 John Wiley & Sons, Ltd.
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Objectives To analyse demographic and clinical variables in patients with disease onset before and after 40, 45 and 50 years in a large series of Brazilian SpA patients. Methods A common protocol of investigation was prospectively applied to 1424 SpA patients in 29 centres distributed through the main geographical regions in Brazil. The mean age at disease onset was 28.56 +/- 12.34 years, with 259 patients (18.2%) referring disease onset after 40 years, 15.1 (10.6%) after 45 years and 81 (5.8%) after 50 years. Clinical and demographic variables and disease indices (BASDAI, BASFI, BASRI, MASES, ASQoL) were investigated. Ankylosing spondylitis was the most frequent disease (66.3%), followed by psoriatic arthritis (18%), undifferentiated SpA (6.7%), reactive arthritis (5.5%), and enteropathic arthritis (3.5%). Results Comparing the groups according to age of disease onset, those patients with later onset presented statistical association with female gender, peripheral arthritis, dactylitis, nail involvement and psoriasis, as well as negative statistical association with inflammatory low hack pain, alternating buttock pain, radiographic sacroiliitis, hip involvement, positive familial history, HLA-B27 and uveitis. BASDAI, BASFI and quality of life, as well as physicians and patient's global assessment, were similar in all the groups. Radiographic indices showed worse results in the younger age groups. Conclusion There are two different clinical patterns in SpA defined by age at disease onset: one with predominance of axial symptoms in the group with disease onset <= 40 years and another favouring the peripheral manifestations in those with later disease onset.
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Os indicadores sociais se tornaram imprescindíveis no elenco de variáveis dos estudos epidemiológicos a partir da constatação de que a determinação dos agravos à saúde é complexa e multidimensional. Nessa perspectiva, a desigualdade social vem ocupando destaque como um fator explicativo das condições de saúde das populações. O objetivo é discutir as diferentes concepções que norteiam a seleção dos indicadores utilizados nos estudos epidemiológicos e abordar os efeitos psicossociais nos seres humanos acarretados pela desigualdade social. Foi realizada uma revisão da literatura acerca dos estudos epidemiológicos que utilizaram os indicadores de desigualdade social e capital social para uma melhor compreensão dos problemas de saúde, bem como uma investigação no campo da sociologia e da psicologia social. De acordo com a pesquisa pode-se constatar que há controvérsias sobre o efeito da desigualdade social na saúde humana pelo fato desses indicadores serem baseados, majoritariamente, pela renda e capacidade de consumo dos indivíduos. Da mesma forma, os indicadores de capital social em nível cognitivo e estrutural são muito limitados para compreender o dinamismo das relações sociais. Nesse sentido, são necessários mais estudos para a construção de indicadores sociais que contemplem a complexidade das sociedades modernas.