45 resultados para indices
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Soil surface roughness is known to influence water infiltration, runoff and erosion. Soil surface roughness changes with management and weather and its mathematical description still remains an important issue. The main objective of this study was to investigate the effect of tillage on the two fractal indices, fractal dimension, D, and crossover length, 1, currently used in characterizing soil surface microrelief. The statistical index random roughness, RR, was also assessed. Field experiments were done on an Alfisol located at Rio Grande do Sul State (Brazil). Two tillage treatments (conventional versus direct drilling) were tested. The soil surface microrelief was assessed by point elevation measurements in 16 plots for each treatment. The sampling scheme was a square grid with 20 x 20 mm between point spacing and the plot size was 280 x 280 mm, so that each data set consisted of 225 individual elevation points. All indices were calculated after trend removal, both by slope correction, i.e., oriented microrelief, and by slope plus tillage marks correction, i.e., random microrelief. The implemented algorithm for estimating D and 1 consisted in evaluating the roughness around the local root mean square deviation (RMS) of the point elevation values. Irrespective of tillage treatment and detrending procedure, fractal behavior extended only over a bounded range of scales, from 40 to 100 mm, due to the experimental setup. In these conditions, assessing fractal indices was not always straightforward. The statistical index RR and the fractal index I were significantly different between tillage treatments for oriented and random surface conditions. D values of random soil surfaces were not affected by tillage treatment, whereas D values of oriented microrelief were significantly lower in the direct drilled plots. Removal of tillage marks trend resulted in a significant increase in D values. Within each tillage treatment, 1 and D were significantly correlated. (c) 2006 Elsevier B.V. All rights reserved.
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Considering the controversy in the literature regarding several aspects of temporomandibular dysfunction (TMD) in elderly populations and the absence of reliable data on elderly Brazilians in this field, this study consisted of an evaluation of TMD prevalence and the self-perception of oral health among institutionalised and community-dwelling elderly in Sao JosE dos Campos, Brazil.Two hundred and fifteen community-dwelling and 185 institutionalised elderly people were evaluated by the Helkimo anamnestic (Ai) and clinical dysfunction (Di) indices and answered a questionnaire using the Geriatric Oral Health Assessment Index (GOHAI).The major prevalence of TMD symptoms was for the Ai0 (symptom-free) group (69.5%), while the major prevalence of clinical signs was for the DiI (mild) group (56%). Women presented a higher AiII classification than men (chi(2) test, p = 0.049). Community-dwelling elderly presented a significantly lower Ai0 classification than the institutionalised ones (Two ratios equality test, p < 0.001). There was no relationship between the institutionalised status and the clinical dysfunction index for Di0 and DiIII classification (Two ratios equality test, p = 0.194 and 0.535 respectively). The institutionalised elderly presented greater (One-way anova = 0.005) self-perception of oral health (33.45) than did the community-dwelling group (32.66). There were only weak Pearson's correlations among the anamnestic (-33.0%) or clinical (-14.7%) findings by the TMD and GOHAI indices. Symptom-free (Ai0) institutionalised elderly presented better scores in all GOHAI dimensions and elderly representing an absence of clinical TMD signs (Di0) presented higher GOHAI physical dimension scores in both groups.The prevalence of TMD symptoms among this sample of elderly individuals was relatively low, self-perception of oral health was reasonable and a weak, inverse correlation was found between TMD signs and symptoms and elderly self-perception of oral health measured by the GOHAI index.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The quantification of the degree of activity of inflammatory bowel disease is assuming growing importance nowadays. The activity index of the disease can be attained by clinical and laboratorial indicators. For ulcerative colitis the mostly used clinical parameters are daily bowel movements and presence of bloody diarrhea whereas albumin, hemoglobin, ESR and positive acute phase protein measurements are the laboratory parameters. For Crohn's disease activity besides the daily bowel movements the presence of abdominal pain and discomfort sensation are also frequently used whereas the C-reactive protein is the most used laboratory test which is able to detect the disease reactivation even before the appearance of any clinical sign. The combinations of clinical signs with the laboratory tests earned the sympathy of the specialists and the set of ensembled indicators has been recognized by the author's name. In this sense, the classification of the ulcerative colitis activity originally proposed by Truelove and Witts deserves presently a wide acceptance whereas such agreement is still lacking for Crohn's disease activity. In the mean time, the Bristol index is clinically the most feasible, once the Crohn's disease activity index and the Van Hees index are considered too complex. However the latter indexes are still useful mainly for comparisons among multicentric data. It seems that the currently existing clinical signs used for Crohn's disease activity would be quantitatively improved by adding some easily made laboratory tests such as C-reactive protein.
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The objectives of this study were to verify the effects of wet suits (WS) on the performance during 1500m swimming (V1500), on the velocity corresponding to the anaerobic threshold (VAT) and on the drag force (AD) as well as its coefficient (Cx). 19 swimmers randomly completed the following protocols on different days (with and without WS): 1) maximal performance of 1500m swimming; 2) VAT in field test, with fixed concentration of blood lactate (4 mM) and 3) determination of hydrodynamic indices (AD and Cx). The results demonstrated significant differences (p < 0.05) in the VAT (1.27±0.09; 1.21±0.06 m.s-1), and in the V1500 (1.21±0.08; 1.17±0.08 m.s-1), with and without WS, respectively. However the AD, and its Cx did not present significant differences (p>0.05) for the respective maximal speeds of swimming. In summary, we can conclude that WS allows swimmers to reach greater speeds in both, long- and short-course swims. This improvement can be related to the decrease of the AD, since with higher speeds (with WS) the subjects presented the same resistance, as they did when compared to speeds without a WS. Moreover, these data suggest that the methodology used in this study to determine the Cx is unable to detect the improvement caused by WS.
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This paper deals with hybrid method for transient stability analysis combining time domain simulation and a direct method. Nowadays, the step-by-step simulation is the best available tool for allowing the uses of detailed models and for providing reliable results. The main limitation of this approach involves the large time of computational simulations and the absence of stability margin. On the other hand, direct methods, that demand less CPU time, did not show ample reliability and applicability yet. The best way seems to be using hybrid solutions, in which a direct method is incorporated in a time domain simulation tool. This work has studied a direct method using the transient potential and kinetic energy of the critical machine only. In this paper the critical machine is identified by a fast and efficient method, and the proposal is new for using to get stability margins from hybrid approaches. Results from systems, like 16-machine, show stability indices to dynamic security assessment. © 2001 IEEE.
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Reliability of power supply is related, among other factors, to the control and protection devices allocation in feeders of distribution systems. In this way, optimized allocation of sectionalizing switches and protection devices in strategic points of distribution circuits, improves the quality of power supply and the system reliability indices. In this work, it is presented a mixed integer non-linear programming (MINLP) model, with real and binary variables, for the sectionalizing switches and protection devices allocation problem, in strategic sectors, aimed at improving reliability indices, increasing the utilities billing and fulfilling exigencies of regulatory agencies for the power supply. Optimized allocation of protection devices and switches for restoration, allows that those faulted sectors of the system can be isolated and repaired, re-managing loads of the analyzed feeder into the set of neighbor feeders. Proposed solution technique is a Genetic Algorithm (GA) developed exploiting the physical characteristics of the problem. Results obtained through simulations for a real-life circuit, are presented. © 2004 IEEE.
A new method for real time computation of power quality indices based on instantaneous space phasors
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One of the important issues about using renewable energy is the integration of dispersed generation in the distribution networks. Previous experience has shown that the integration of dispersed generation can improve voltage profile in the network, decrease loss etc. but can create safety and technical problems as well, This work report the application of the instantaneous space phasors and the instantaneous complex power in observing performances of the distribution networks with dispersed generators in steady state. New IEEE apparent power definition, the so called Buccholz-Goodhue apparent power, as well as new proposed power quality (oscillation) index in the three-phase distribution systems with unbalanced loads and dispersed generators, are applied. Results obtained from several case studies using IEEE 34 nodes test network are presented and discussed.
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Nonlinear (NL) optical properties of antimony oxide based glasses (AG) were characterized for excitation wavelengths from 800 to 1600 m. The NL refractive indices, n2, and the two-photon absorption (TPA) coefficient, β, have been evaluated using the Z-scan technique. Values of n2≈ 10-15 - 10-14 cm2/W of electronic origin were measured and negligible TPA coefficients (β < 0.003 cm/GW) were determined. The response time of the nonlinearity is faster than 100 fs as determined using the Kerr shutter technique. The figure-of-merit usually considered for all-optical switching, T = 2βλ/n2 , indicates that AG are very good materials for ultrafast switches at telecom wavelengths. © 2007 IEEE.
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Estimates of gain with selection are very useful in breeding programs to predict the success of selection. Index-based simultaneous selection makes breeding more successful. The objective of this report was to estimate and compare the genetic gain obtained by direct and indirect selection and using the classical and based on desired gain indices. The experiment was set up in the design of families with intercalated checks with 293 F3 soybean genotypes, distributed in 32 families derived from five crosses. Individual gains obtained with direct selection among and within families and mass selection were similar and in most cases higher than selection by indices. On the other hand, the highest total gains were obtained with selection indices and distributed across all traits. The classical index obtained the highest genetic gains.
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Background: Decreased heart rate variability (HRV) is related to higher morbidity and mortality. In this study we evaluated the linear and nonlinear indices of the HRV in stable angina patients submitted to coronary angiography. Methods. We studied 77 unselected patients for elective coronary angiography, which were divided into two groups: coronary artery disease (CAD) and non-CAD groups. For analysis of HRV indices, HRV was recorded beat by beat with the volunteers in the supine position for 40 minutes. We analyzed the linear indices in the time (SDNN [standard deviation of normal to normal], NN50 [total number of adjacent RR intervals with a difference of duration greater than 50ms] and RMSSD [root-mean square of differences]) and frequency domains ultra-low frequency (ULF) ≤ 0,003 Hz, very low frequency (VLF) 0,003 - 0,04 Hz, low frequency (LF) (0.04-0.15 Hz), and high frequency (HF) (0.15-0.40 Hz) as well as the ratio between LF and HF components (LF/HF). In relation to the nonlinear indices we evaluated SD1, SD2, SD1/SD2, approximate entropy (-ApEn), α1, α2, Lyapunov Exponent, Hurst Exponent, autocorrelation and dimension correlation. The definition of the cutoff point of the variables for predictive tests was obtained by the Receiver Operating Characteristic curve (ROC). The area under the ROC curve was calculated by the extended trapezoidal rule, assuming as relevant areas under the curve ≥ 0.650. Results: Coronary arterial disease patients presented reduced values of SDNN, RMSSD, NN50, HF, SD1, SD2 and -ApEn. HF ≤ 66 ms§ssup§2§esup§, RMSSD ≤ 23.9 ms, ApEn ≤-0.296 and NN50 ≤ 16 presented the best discriminatory power for the presence of significant coronary obstruction. Conclusion: We suggest the use of Heart Rate Variability Analysis in linear and nonlinear domains, for prognostic purposes in patients with stable angina pectoris, in view of their overall impairment. © 2012 Pivatelli et al.; licensee BioMed Central Ltd.
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Background: Metabolic and morphological changes associated with excessive abdominal fat, after the introduction of Antiretroviral Therapy, increase the risk of cardiovascular disease in people living with HIV/AIDS(PLWHA). Accurate methods for body composition analysis are expensive and the use of anthropometric indices is an alternative. However the investigations about this subject in PLWHA are rare, making this research very important for clinical purpose and to advance scientific knowledge. The aim of this study is to correlate results of anthropometric indices of evaluation of body fat distribution with the results obtained by Dual-energy X-Ray Absorptiometry(DEXA) , in people living with HIV/AIDS. Methods. The sample was of 67 PLWHA(39 male and 28 female), aged 43.6+7.9 years. Body mass index, conicity index, waist/hip ratio, waist/height ratio and waist/thigh were calculated. Separated by sex, each index/ratio was plotted in a scatter chart with linear regression fit and their respective Pearson correlation coefficients. Analyses were performed using Prism statistical program and significance was set at 5%. Results: The waist/height ratio presented the highest correlation coefficient, for both male (r=0.80, p<0.001) and female (r=0.87, p <001), while the lowest were in the waist/thigh also for both: male group (r=0.58, p<0.001) and female group (r=0.03, p=0.86). The other indices also showed significant positive correlation with DEXA. Conclusion: Anthropometric indices, especially waist/height ratio may be a good alternative way to be used for evaluating the distribution of fat in the abdominal region of adults living with HIV/ADIS. © 2012 Segatto et al.; licensee BioMed Central Ltd.
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Genetic correlations of selection indices and the traits considered in these indices with mature weight (MW) of Nelore females and correlated responses were estimated to determine whether current selection practices will result in an undesired correlated response in MW. Genetic trends for weaning and yearling indices and MW were also estimated. Data from 612,244 Nelore animals born between 1984 and 2010, belonging to different beef cattle evaluation programs from Brazil and Paraguay, were used. The following traits were studied: weaning conformation (WC), weaning precocity (WP), weaning muscling (WM), yearling conformation (YC), yearling precocity (YP), yearling muscling (YM), weaning and yearling indices, BW gain from birth to weaning (BWG), postweaning BW gain (PWG), scrotal circumference (SC), and MW. The variance and covariance components were estimated by Bayesian inference in a multitrait analysis, including all traits in the same analysis, using a nonlinear (threshold) animal model for visual scores and a linear animal model for the other traits. The mean direct heritabilities were 0.21 ± 0.007 (WC), 0.22 ± 0.007 (WP), 0.20 ± 0.007 (WM), 0.43 ± 0.005 (YC), 0.40 ± 0.005 (YP), 0.40 ± 0.005 (YM), 0.17 ± 0.003 (BWG), 0.21 ± 0.004 (PWG), 0.32 ± 0.001 (SC), and 0.44 ± 0.018 (MW). The genetic correlations between MW and weaning and yearling indices were positive and of medium magnitude (0.30 ± 0.01 and 0.31 ± 0.01, respectively). The genetic changes in weaning index, yearling index, and MW, expressed as units of genetic SD per year, were 0.26, 0.27, and 0.01, respectively. The genetic trend for MW was nonsignificant, suggesting no negative correlated response. The selection practice based on the use of sires with high final index giving preference for those better ranked for yearling precocity and muscling than for conformation generates only a minimal correlated response in MW. © 2013 American Society of Animal Science. All rights reserved.
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Body size is directly related to the productive and reproductive performance of beef cattle raised under free-range conditions. In an attempt to better plan selection criteria, avoiding extremes in body size, this study estimated the heritabilities and genetic correlations of yearling hip height (YH) and mature hip height (MH) with selection indices obtained at weaning (WI) and yearling (YI) and mature weight (MW). Data from 102,373 Nelore animals born between 1984 and 2010, which belong to 263 farms that participate in genetic evaluation programmes of beef cattle conducted in Brazil and Paraguay, were used. The (co)variance components and genetic parameters were estimated by Bayesian inference in multi-trait analysis using an animal model. The mean heritabilities for YH, MH and MW were 0. 56 ± 0. 06, 0. 47 ± 0. 02 and 0. 42 ± 0. 02, respectively. The genetic correlation of YH with WI (0. 13 ± 0. 01) and YI (0. 11 ± 0. 01) was practically zero, whereas a higher correlation was observed with MW (0. 22 ± 0. 03). Positive genetic correlations of medium magnitude were estimated between MH and WI and YI (0. 23 ± 0. 01 and 0. 43 ± 0. 02, respectively). On the other hand, a high genetic correlation (0. 68 ± 0. 03) was observed between the indicator traits of mature body size (MH and MW). Considering the top 20 % of sire (896 sires) in terms of breeding values for the yearling index, the rank sire correlations between breeding values for MH and MW was 0. 62. In general, the results indicate that selection based on WI and YI should not lead to important changes in YH. However, an undesired correlated response in mature cow height is expected, particularly when selection is performed using YI. Therefore, changes in the body structure of Nelore females can be obtained when MH and MW is used as a selection criterion for cows. © 2012 Institute of Plant Genetics, Polish Academy of Sciences, Poznan.