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In the current context of distance learning, learning management systems (LMSs) make it possible to store large volumes of data on web browsing and completed assignments. To understand student behavior patterns in this type of environment, educators and managers must rethink conventional approaches to the analysis of these data and use appropriate computational solutions, such as educational data mining (EDM). Previous studies have tested the application of EDM on small datasets. The main contribution of the present study is the application of EDM algorithms and the analysis of the results in a massive course delivered by a Brazilian University to 181,677 undergraduate students enrolled in different fields. The use of key algorithms in educational contexts, such as decision trees and clustering, can reveal relevant knowledge, including the attribute type that most significantly contributes to passing a course and the behavior patterns of groups of students who fail.

Purpose: To replicate previous genome-wide association study identified sprint-related polymorphisms in 3 different cohorts of top-level sprinters and to further validate the obtained results in functional studies. Methods: A total of 240 Japanese, 290 Russians, and 593 Brazilians were evaluated in a case-control approach. Of these, 267 were top-level sprint/power athletes. In addition, the relationship between selected polymorphisms and muscle fiber composition was evaluated in 203 Japanese and 287 Finnish individuals. Results: The G allele of the rs3213537 polymorphism was overrepresented in Japanese (odds ratio [OR]: 2.07, P =.024) and Russian (OR: 1.93, P =.027) sprinters compared with endurance athletes and was associated with an increased proportion of fast-twitch muscle fibers in Japanese (P =.02) and Finnish (P =.041) individuals. A meta-analysis of the data from 4 athlete cohorts confirmed that the presence of the G/G genotype rather than the G/A+A/A genotypes increased the OR of being a sprinter compared with controls (OR: 1.49, P =.01), endurance athletes (OR: 1.79, P =.001), or controls + endurance athletes (OR: 1.58, P =.002). Furthermore, male sprinters with the G/G genotype were found to have significantly faster personal times in the 100-m dash than those with G/A+A/A genotypes (10.50 [0.26] vs 10.76 [0.31], P =.014). Conclusion: The rs3213537 polymorphism found in the CPNE5 gene was identified as a highly replicable variant associated with sprinting ability and the increased proportion of fast-twitch muscle fibers, in which the homozygous genotype for the major allele (ie, the G/G genotype) is preferable for performance. [ABSTRACT FROM AUTHOR]

Sweet potato chlorotic stunt virus (SPCSV; genus Crinivirus, family Closteroviridae), is an economically important pathogen of sweet potato. In the present work, the nucleotide sequences of two RNA segments of SPCSV (isolate SPCSV-UNB-01) were determined by MiSeq Illumina sequencing of samples of sweet potato plants grafted onto Ipomoea setosa. A comparative analysis of the genome organization of SPCSV-UNB-01 and other SPCSV sequences showed that RNA1 was lacking p22, and p5.1 and that p5.2. was absent in RNA2, indicating a unique genomic pattern. SPCSV-UNB-01 contained longer p6 and p5 regions, with little similarity to orthologous sequences. Sequence comparison did not reveal any previously identified functional domains within these open reading frames (ORFs). No recombination or rearrangement events were detected. Phylogenetic analysis suggested the possibility of separate entries of SPCSV into South America based on the genetic distance between SPCSV-UNB-01 and the Peruvian isolate m2-47. Samples from northeastern Brazil (State of Pernambuco) were positive for SPCSV when tested using specific primers for the major coat protein (CP) gene. This is the first full-length genome sequence of SPCSV-UNB-01 from Brazil. [ABSTRACT FROM AUTHOR]

A new bipartite begomovirus (family Geminiviridae) was detected on cowpea (Vigna unguiculata) plants exhibiting bright golden mosaic symptoms on leaves under field conditions in Brazil. Complete consensus sequences of DNA-A and DNA-B components of an isolate of the virus (PE–088) were obtained by nanopore sequencing and confirmed by Sanger sequencing. The genome components presented the typical genomic organization of New World (NW) begomoviruses. Pairwise sequence comparisons revealed low levels of identity with other begomovirus species previously reported infecting cowpea around the world. Phylogenetic analysis using complete sequences of DNA-A components revealed that the closest relatives of PE–088 (85-87% nucleotide sequence identities) were three legume-infecting begomoviruses from Brazil: bean golden mosaic virus, macroptilium common mosaic virus and macroptilium yellow vein virus. According to the current classification criteria, PE–088 represents a new species in the genus Begomovirus, tentatively named as cowpea bright yellow mosaic virus (CoBYMV). [ABSTRACT FROM AUTHOR]

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Helicobacter pylori, especially the cytotoxin-associated antigen A ( cagA)-positive strains, plays a crucial role in the development of gastric atrophy and gastric cancer. CagA delivered into gastric epithelial cells combines with src homology 2 domain-containing protein tyrosine phosphatase-2 (SHP-2), possibly leading to atrophy/cancer. Our previous study found that a single-nucleotide polymorphism (SNP; IMS-JST057927) of the PTPN11 gene encoding SHP-2, was associated with gastric atrophy among H. pylori-seropositive subjects. This study aimed to examine the reproducibility of the association among Japanese residing in a different circumstance. The subjects were 918 healthy adult Japanese Brazilians from four different areas in Brazil. Blood was sampled from March to May 2001. The target SNP in intron 3 of PTPN11 was genotyped by polymerase chain reaction with confronting two-pair primers (PCR-CTPP). Gastric atrophy was evaluated with serum pepsinogens (PGs); PG I, less than 70 ng/dl and PG I/II ratio, less than 3. The genotype frequency of PTPN11 was in Hardy-Weinberg equilibrium: 65.5% for G/ G, 30.4% for G/ A, and 4.1% for A/ A. The PTPN11 polymorphism had no significant association with H. pylori seropositivity. Among the H. pylori-seropositive subjects, the odds ratios (ORs) of gastric atrophy were 0.93 (95% confidence interval [CI], 0.59–1.47) for the G/ A genotype and 0.31 (95% CI, 0.10–0.95) for the A/ A genotype, compared with the G/ G genotype. The present study reproduced the significant association between the A/ A genotype and reduced risk of gastric atrophy among Japanese outside Japan. According to the Japan Single Nucleotide Polymorphisms (JSNP) database (db)SNP data, the G allele is very frequent among Japanese and rare in Caucasians. This fact may partly explain the distribution of gastric atrophy/cancer in the world. [ABSTRACT FROM AUTHOR]