Federal Institute for Education

Rio Grande, Brazil

Federal Institute for Education

Rio Grande, Brazil
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De Andrade Fernandes A.,Federal University of Viçosa | De Andrade Fernandes A.,Federal Institute for Education | Dos Santos Amorim P.R.,Federal University of Viçosa | Brito C.J.,Federal University of Sergipe | And 5 more authors.
Physiological Measurement | Year: 2014

Measuring skin temperature (TSK) provides important information about the complex thermal control system and could be interesting when carrying out studies about thermoregulation. The most common method to record TSK involves thermocouples at specific locations; however, the use of infrared thermal imaging (IRT) has increased. The two methods use different physical processes to measure TSK, and each has advantages and disadvantages. Therefore, the objective of this study was to compare the mean skin temperature (MTSK) measurements using thermocouples and IRT in three different situations: pre-exercise, exercise and post-exercise. Analysis of the residual scores in Bland-Altman plots showed poor agreement between the MTSK obtained using thermocouples and those using IRT. The averaged error was -0.75 °C during pre-exercise, 1.22°C during exercise and -1.16°C during post-exercise, and the reliability between the methods was low in the pre- (ICC = 0.75 [0.12 to 0.93]), during (ICC = 0.49 [-0.80 to 0.85]) and post-exercise (ICC = 0.35 [-1.22 to 0.81] conditions. Thus, there is poor correlation between the values of MTSK measured by thermocouples and IRT pre-exercise, exercise and post-exercise, and low reliability between the two forms of measurement. © 2014 Institute of Physics and Engineering in Medicine.

Neves F.A.S.,Federal University of Pernambuco | De Souza H.E.P.,Federal Institute for Education | Cavalcanti M.C.,Federal University of Pernambuco | Bradaschia F.,Federal University of Pernambuco | Bueno E.J.,University of Alcalá
IEEE Transactions on Industrial Electronics | Year: 2012

In this paper, two methods for determining the fundamental frequency and harmonic positive- and negative-sequence components of three-phase signals are investigated. Many aspects of the space-vector discrete Fourier transform and generalized delayed signal cancellation (GDSC) such as response time for different possible implementations, frequency adaptation schemes, stability of recursive implementation, and rounding error effects are discussed. A new design procedure for GDSC transformations is presented. New indices for characterizing three-phase unbalanced and distorted signals are proposed. Simulations and experiments are included in order to verify the performances and illustrate the theoretical conclusions. © 2012 IEEE.

Cerqueira M.,Federal University of Viçosa | Cerqueira M.,Federal Institute for Education | Amorim P.,Federal University of Viçosa | Magalhaes F.,Iguaçu University | And 6 more authors.
Obesity | Year: 2013

Objective This study aimed to verify the validity of BAI in predicting %BF in a sample of Brazilian women Design and Methods A total of 102 women (average age 60.3 ± 9.8) were assessed. To determine percentage body fat (% BF), dual-energy X-ray absorptiometry (DXA) was used as the "gold standard." To evaluate the association between body adiposity index (BAI) and % BF assessed by DXA, we used Pearson's correlation coefficient. Paired sample t-test was used to test differences in mean % BF between BAI and DXA. To evaluate the concordance between % BF measured by DXA and estimated by BAI, we used the Lin's concordance correlation coefficient and the agreement analysis of Bland-Altman. Results The correlation between % BF obtained by DXA and that estimated by BAI was r = 0.65, P < 0.001. Paired t-test showed significant mean difference between methods (P < 0.0001). Lin's concordance correlation coefficient was C-b = 0.73, which is classified as poor, while the Bland-Altman plots showed BAI underestimating % BF in relation to the used criterion measure in a large portion of the sample. Conclusions Results of the present study show that BAI presented low agreement with % BF measured by DXA, which is not recommended for % BF prediction in this studied sample. Copyright © 2013 The Obesity Society.

Neves F.A.S.,Federal University of Pernambuco | De Souza H.E.P.,Federal University of Pernambuco | De Souza H.E.P.,Federal Institute for Education | Bradaschia F.,Federal University of Pernambuco | And 3 more authors.
IEEE Transactions on Industrial Electronics | Year: 2010

In this paper, a space-vector discrete-time Fourier transform is proposed for fast and precise detection of the fundamental-frequency and harmonic positive- and negative-sequence vector components of three-phase input signals. The discrete Fourier transform is applied to the three-phase signals represented by Clarke's $\alpha\beta$ vector. It is shown that the complex numbers output from the Fourier transform are the instantaneous values of the positive- and negative-sequence harmonic component vectors of the input three-phase signals. The method allows the computation of any desired positive- or negative-sequence fundamental-frequency or harmonic vector component of the input signal. A recursive algorithm for low-effort online implementation is also presented. The detection performance for variable-frequency and interharmonic input signals is discussed. The proposed and other usual method performances are compared through simulations and experiments. © 2006 IEEE.

Fontes A.G.,Federal Institute for Education | Gama-Rodrigues A.C.,State University of Norte Fluminense | Gama-Rodrigues E.F.,State University of Norte Fluminense | Sales M.V.S.,State University of Norte Fluminense | Costa M.G.,State University of Norte Fluminense
Plant and Soil | Year: 2014

Aim: To compare the internal balances of nutrients and the rates of nutrient cycling across nine cocoa agroforestry systems consisting of various combination of soil types (Latosols and Cambisols), production systems (cabruca and Erythrina glauca-shade) and fertilization regimes in southern Bahia, Brazil.Methods: We measured nutrient stocks in litter fall production, in the accumulated litter and fruits. The internal nutrient balance for various simulations was obtained by the following expressions: (1) Balance 1 = litter – fruit (seeds and husks) and (2) Balance 2 = (litter + husks) – seeds. Annual litter decomposition coefficients (k) and subsequent potential of nutrient release were also investigated. The data were analyzed by principal components analysis and by Pearson correlations.Results: There was a high degree of dissimilarity among the cocoa agrosystems in relation to the nutrient cycling and the internal nutrient balance. The mean annual litterfall production ranged from 4.6 to 8.5 Mg/ha, and the amount of accumulated litter ranged from 7.7 to 16.8 Mg/ha. The results showed significant differences in quality among litter from cocoa agroforests; the decomposition coefficient of litter and the subsequent nutrient release were regulated by the litter quality. In general, the cocoa-erythrina system presented a higher capacity to recycle nutrients compared to the cocoa-cabruca system, with the cocoa-erythrina system having the largest transfer rate of nutrients through litterfall, high values for the decomposition coefficient of litter and the lowest values for the Mean Residence Time of nutrients. Cocoa tree leaves functioned as a sink of nutrients, while shade tree leaves functioned predominantly as a source. The nutritional reserves of litter + cocoa fruit husks, with respect only to the nutrients exported in the seeds, the balance was positive for all nutrients (N, P, K, Ca and Mg) in all agroforests, which emphasizes the potential productive capacity of these agroforests to sustain the estimated production in different harvest cycles.Conclusions: The internal balance of nutrients reflects an agroforests’s productive capacity, which accumulated litter and cocoa fruit husks may be important nutrient sources that could enable the development of fertilizer recommendation systems aimed at increasing the efficiency of fertilizer use and at maintaining soil fertility in cocoa agroforests. Therefore, further research is needed to develop nutritional balance systems integrating litter + fruits stock and other nutrient pathways (e.g., soil quality, biological N fixation, leaching), which were not measured, for making recommendations regarding liming and fertilizers that are suitable for highly complex biological agrosystems, such as cocoa agroforests that have low levels of elements exported during seed production. © 2014, Springer International Publishing Switzerland.

PubMed | Queensland University of Technology, Federal University of Maranhão, Technical University of Madrid, Cruzeiro Esporte Clube and 3 more.
Type: Journal Article | Journal: Journal of thermal biology | Year: 2016

Research into obtaining a fast, valid, reliable and non-invasive measure of core temperature is of interest in many disciplinary fields. Occupational and sports medicine research has attempted to determine a non-invasive proxy for core temperature particularly when access to participants is limited and thermal safety is of a concern due to protective encapsulating clothing, hot ambient environments and/or high endogenous heat production during athletic competition. This investigation aimed to determine the validity of inner canthus of the eye temperature (T

Santos J.C.F.,Federal University of Alagoas | Valentim I.B.,Federal University of Alagoas | Valentim I.B.,Federal Institute for Education | de Araujo O.R.P.,Federal University of Alagoas | And 2 more authors.
International Journal of Molecular Sciences | Year: 2013

Advanced glycation end products (AGEs) are generated spontaneously in cells; however, under conditions of hyperglycemia and lipid peroxidation, their levels are higher than usual, which contribute to the development of diseases such as the nonalcoholic fatty liver disease (NAFLD). NAFLD is associated with oxidative stress (OS), which is linked to the transition of steatosis to steatohepatitis due to lipid peroxidation. The AGE-receptor interaction in hepatic stellate cells leads to an increase in reactive oxygen species and enhances the proliferation and activation of these cells, worsening liver fibrosis and disease progression. In this vicious cycle, there is production of (carboxymethyl)lysine, a biomarker for products of advanced glycation and lipid peroxidation, being a shared component between the two pathways. In this review, we aim to compile evidence to support the basic molecular mechanisms of AGEs and OS generation and their influence, independently or combined, on the evolution of NAFLD. The deeper understanding of the interrelations of AGEs + OS may help to elucidate the pathogenic pathways of NAFLD and to devise rational therapeutic interventions for this disease, with an expected positive impact on quality of life of patients. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Vicente C.D.,Federal Institute for Education | de Abreu F.C.,Federal University of Alagoas | Goulart M.O.F.,Federal University of Alagoas | de Vasconcelos J.N.,Federal University of Alagoas
American Journal of Food Technology | Year: 2011

This study quantified the phenolic compounds (gallic acid, vanillic acid, vanillin, syringic acid, syringaldehyde, coumarin and scopoletin), furfuraldehyde and the antioxidant capacity during in 0, 1, 3, 6, 9, 12 and 18 months of non-aged cachaca and active aging of cachaca in 20 L casks of four Brazilian wood species, white peroba (Paratecoma white peroba), balsamo (Myroxylon balsamum), timborana (Piptadenia sp.), jaboty (Erisma uncinatum) and white oak (Quercus sp.) casks. The content of phenolic compounds and 2-furfuraldehyde were quantified by HPLC-UV. The antioxidant capacity was determined using two indirect methods: The total phenolic content by Folin-Ciocalteu assay and the inhibition of 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical. The phenolic compounds incorporated in aged cachacas after 18 months of aging were: jaboty (gallic acid and vanillin), white oak (gallic acid, vanillic acid, vanillin, syringic acid and syringaldehyde), timborana (gallic acid, vanillic acid, vanillin and coumarin), balsamo (gallic acid, vanillic acid, vanillin, syringic acid, syringaldehyde and coumarin) white peroba (gallic acid, vanillic acid, vanillin, syringic acid, syringaldehyde and coumarin). The antioxidant capacity and content of phenolic compounds both increase with increasing aging time and there is a significant correlation between them. The Brazilian woods balsam, followed by white peroba and timborana were the best substitute to replace the oak casks because their aged cachacas presented higher antioxidant capacity and phenolic profile more complex and quantitatively greater than the cachaca aged in white oak casks. This work suggests that 2-furfuraldehyde can degrade in cachaca aged in timborana, white peroba and balsamo. © 2011 Academic Journals Inc.

Zanotta D.C.,Federal Institute for Education | Bruzzone L.,University of Trento | Bovolo F.,Fondazione Bruno Kessler | Shimabukuro Y.E.,National Institute for Space Research
IEEE Transactions on Geoscience and Remote Sensing | Year: 2015

In this paper, we present a novel domain adaptation technique aimed at providing reliable change detection maps for a series of image pairs acquired on the same area at different times. The proposed technique exploits the polar change vector analysis method and assumes that the reference data for characterizing a specific change of interest are available only for a pair of images (source domain). Then, it exploits the knowledge learned from the source domain and adapts it to other pairs of images belonging to the time series (target domains) to be analyzed. The proposed technique is able to handle possible radiometric differences among images adapting in an unsupervised way the decision rule estimated on the source domain to the target domains through variables estimated directly on the target images. The proposed approach has been applied to two data sets made up of time series of Landsat Thematic Mapper images. In one case, the change of interest is related to evolution of deforestation, while in the other case, it is related to burned area detection. Experimental results show the effectiveness of the proposed technique. © 1980-2012 IEEE.

Nogueira P.E.,Federal Institute for Education | Matias Jr. R.,Federal University of Uberlandia | Vicente E.,Federal University of Triângulo Mineiro
Proceedings of the ACM Symposium on Applied Computing | Year: 2014

In computer experiments, many research works rely on the accuracy of measured programs' execution time. We observe that not all studies consider that repeated executions of the same program, under the same experimental conditions, may produce statistically significant different completion times. In this work, we experimentally demonstrate that several sources of OS Jitter affect the execution time of computer programs. We compare various execution time samples using three test protocols, which apply different statistical techniques. The results show that significant differences are detected in all evaluated scenarios. Copyright 2014 ACM.