Low vitamin D blood levels are linked to greater risk of heart disease in whites and Chinese, but not in blacks and Hispanics, according to a study appearing this week in JAMA, the Journal of the American Medical Association.
Growing evidence has suggested that low blood levels of 25-hydroxyvitamin are associated with higher risk of developing coronary heart disease among whites. Few of these studies included substantial numbers of people from other races. (more…)
The most prestigious peer-reviewed journals in the world, such as Cell, Nature, Science, and the Journal of the American Medical Association (JAMA), have less and less influence amongst scientists, according to a paper co-authored by Vincent Larivière, a professor at the University of Montreal’s School of Library and Information Sciences. He questions the relationship between journal “impact factor” and number of citations subsequently received by papers.
“In 1990, 45% of the top 5% most cited articles were published in the top 5% highest impact factor journals. In 2009, this rate was only 36%,” Larivière said. “This means that the most cited articles are published less exclusively in high impact factor journals.” The proportion of these articles published in major scholarly journals has sharply declined over the last twenty years. His study was based on a sample of more than 820 million citations and 25 million articles published between 1902 and 2009. The findings were published in the Journal of the American Society for Information Science and Technology. (more…)
