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.

Intelligent Connection Agent for Three-Phase Grid-Connected Microgrids

Abstract: The high penetration of distributed generation power plants, based on renewable energy sources (RESs), is boosting the connection of power converters to the electrical network. This generation concept would permit to form local networks, microgrids, when the main grid falls due to any kind of contingency in the network. However, the connection and disconnection of these local networks may give rise to undesired transient overcurrents that should be avoided. In order to solve this drawback, this paper presents a method oriented to carry out a stable intentional disconnection/reconnection of local grids from the main electrical network under grid-fault conditions. This control method has been implemented in a grid-connected power converter that acts as an intelligent connection agent (ICA) and adapts its operation mode according to its connection state. The proposed control also manages the operation of a controlled switch, which is responsible of disconnecting/reconnecting the microgrid from the mains. In this paper, the behavior of the ICA under transient conditions will be discussed, and finally, its simulated and experimental performance will be shown.

Dengue Virus-Specific Antibodies Enhance Brazilian Zika Virus Infection.

Abstract: Anti-Flavivirus antibodies are highly cross-reactive and may facilitate Zika virus (ZIKV) infection through the antibody-dependent enhancement (ADE) mechanism. We demonstrate that dengue-specific antibodies enhance the infection of a primary Brazilian ZIKV isolate in a FcγRII-expressing K562 cell line. In addition, we demonstrate that serum samples from dengue-immune pregnant women enhanced ZIKV infection. These findings highlight the need for epidemiological studies and animal models to further confirm the role of ADE in the development of congenital and neurological complications associated with ZIKV infections.

Revisiting the genetic ancestry of Brazilians using autosomal AIM-Indels.

Abstract: There are many different studies that contribute to the global picture of the ethnic heterogeneity in Brazilian populations. These studies use different types of genetic markers and are focused on the comparison of populations at different levels. In some of them, each geographical region is treated as a single homogeneous population, whereas other studies create different subdivisions: political (e.g., pooling populations by State), demographic (e.g., urban and rural), or ethnic (e.g., culture, self-declaration, or skin colour). In this study, we performed an enhanced reassessment of the genetic ancestry of ~ 1,300 Brazilians characterised for 46 autosomal Ancestry Informative Markers (AIMs). In addition, 798 individuals from twelve Brazilian populations representing the five geographical macro-regions of Brazil were newly genotyped, including a Native American community and a rural Amazonian community. Following an increasing North to South gradient, European ancestry was the most prevalent in all urban populations (with values up to 74%). The populations in the North consisted of a significant proportion of Native American ancestry that was about two times higher than the African contribution. Conversely, in the Northeast, Center-West and Southeast, African ancestry was the second most prevalent. At an intrapopulation level, all urban populations were highly admixed, and most of the variation in ancestry proportions was observed between individuals within each population rather than among population. Nevertheless, individuals with a high proportion of Native American ancestry are only found in the samples from Terena and Santa Isabel. Our results allowed us to further refine the genetic landscape of Brazilians while establishing the basis for the effective application of an autosomal AIM panel in forensic casework and clinical association studies within the highly admixed Brazilian populations.

Influence of previous experience on resistance training on reliability of one-repetition maximum test.

Abstract: The 1-repetition maximum test (1RM) has been widely used to assess maximal strength However, to improve accuracy in assessing maximal strength, several sessions of the 1RM test are recommended The aim of this study was to analyze the influence of previous resistance training experience on the reliability of 1RM test Thirty men were assigned to the following 2 groups according to their previous resistance training experience: no previous resistance training experience (NOEXP) and more than 24 months of resistance training experience (EXP) All subjects performed the 1RM tests in bench press and squat in 4 sessions on distinct days There was a significant session × group effect in bench press (F = 309; p < 003) and squat (F = 276; p < 005) showing that only the NOEXP increased maximal strength between the sessions Significant increases (p < 005) in maximal strength occurred in the NOEXP between session 1 and the other sessions in bench press (session 1 vs 2 = +38%; session 1 vs 3 = +74%; session 1 vs 4 = +101%), and squat (session 1 vs 2 = +76%; session 1 vs 3 = +101%; session 1 vs 4 = +112%) Moreover, in bench press, maximal strength in sessions 3 and 4 were significantly higher than in session 2 The results of the present study suggest that the reliability of the 1RM test is influenced by the subject's previous experience in resistance training Subjects without experience in resistance training require more practice and familiarization and show greater increases in maximal strength between sessions than subjects with previous experience in resistance training