Universidade de Pernambuco

About: Universidade de Pernambuco is a education organization based out in Recife, Brazil. It is known for research contribution in the topics: Population & Artificial neural network. The organization has 6147 authors who have published 6948 publications receiving 73648 citations.

Association between resting heart rate and cardiovascular risk factors in adolescents.

Abstract: This cross-sectional study was performed in 2011 and included 4619 Brazilian adolescents (14–19 years old) to analyze the association between elevated resting heart rate (RHR) and cardiovascular risk factors in boys and girls. RHR and blood pressure were measured using an oscillometric monitor. Overweight was assessed by body mass index and abdominal obesity by waist circumference. Physical activity levels and sedentary behaviors were obtained using a questionnaire. The effect of clustering of cardiovascular risk factors on RHR was analyzed. For boys, abdominal obesity (b = 0.106, p = 0.003), high sedentary behavior (b = 0.099, b < 0.001), physical inactivity (b = 0.049, p = 0.034), and high blood pressure (b = 0.160, p < 0.001) were associated with RHR, whereas for girls, only high blood pressure was associated with RHR (b = 0.259, p < 0.001), after adjustment for age, period of the day, and other cardiovascular risk factors. Boys with five risk factors presented significantly higher (p < 0.05) RHR values (82.5 ± 13.4 beats min−1) than those for boys without any cardiovascular risk factors (68.8 ± 10.4 beats min−1). The girls with five risk factors presented a mean RHR value of 89.8 ± 9.9 beats min−1 that was higher (p < 0.05) than that for girls who had no risk factors (79.6 ± 10.9 beats min−1). Conclusions: Our study demonstrated that while RHR was associated with cardiovascular risk factors in both sexes, the clustering of risk factors amplified the elevation of RHR in a gender-dependent fashion.

Image encryption based on the finite field cosine transform

Abstract: In this paper, a novel image encryption scheme is proposed. The technique involves two steps, where the finite field cosine transform is recursively applied to blocks of a given image. In the first step, the image blocks to be transformed result from the regular partition of subimages of the original image. The transformed subimages are regrouped and an intermediate image is constructed. In the second step, a secret-key determines the positions of the intermediate image blocks to be transformed. Besides complying with the main properties required by image encryption methods, the proposed scheme provides benefits related to computational complexity and encoding of the ciphered-images.

Efeito agudo da intensidade do exercício de força na modulação autonômica cardíaca pós-exercício

Abstract: FUNDAMENTO: O balanco simpatovagal cardiaco se altera apos o exercicio de forca. Contudo, o impacto das caracteristicas do treinamento de forca nessa resposta ainda nao esta claro. OBJETIVO: Analisar o efeito agudo da intensidade do exercicio de forca para tronco e membros superiores na modulacao autonomica cardiaca pos-exercicio. METODOS: Quinze homens jovens realizaram tres sessoes experimentais em ordem aleatoria: controle (C), exercicio de forca com 50% de 1-RM (E50%) e exercicio de forca com 70% de 1-RM (E70%). As sessoes incluiram 05 exercicios para tronco e membro superior, realizados em tres series de 12, 9 e 6 repeticoes, respectivamente. Antes e aos 20 e 50 minutos apos as intervencoes, a frequencia cardiaca foi medida para posterior analise espectral da sua variabilidade. RESULTADOS: Em comparacao aos valores anteriores a intervencao, o intervalo RR e a banda de alta frequencia (AF) aumentaram (maiores alteracoes: + 112 ± 83 ms; +10 ± 11 un, respectivamente, p 0,05). Em comparacao aos valores pre-exercicio, o intervalo RR e a banda AF diminuiram (maiores alteracoes: -69 ± 105 ms; -13 ± 14 un, respectivamente, p < 0,01), enquanto que a banda BF e a razao BF/AF aumentaram (maiores alteracoes: -13 ± 14 un, +13 ± 14 un e +3 ± 3 un, respectivamente, p < 0,01) apos a E70%. CONCLUSAO: A maior intensidade de exercicio de forca para tronco e membros superiores promoveu, agudamente, maior aumento do balanco simpatovagal cardiaco pos-exercicio.