University of Pittsburgh

About: University of Pittsburgh is a education organization based out in Pittsburgh, Pennsylvania, United States. It is known for research contribution in the topics: Population & Transplantation. The organization has 87042 authors who have published 201012 publications receiving 9656783 citations. The organization is also known as: Pitt & Western University of Pennsylvania.

The Acquisition of Reading Comprehension Skill

Abstract: How do people acquire skill at comprehending what they read? That is the simple question to which we shall try to make a tentative answer. To begin, we have to acknowledge some complexities about the concept of reading comprehension and what it means to develop it.

Vaginal Lactobacilli, Microbial Flora, and Risk of Human Immunodeficiency Virus Type 1 and Sexually Transmitted Disease Acquisition

Abstract: A prospective cohort study was conducted to examine the relationship between vaginal colonization with lactobacilli, bacterial vaginosis (BV), and acquisition of human immunodeficiency virus type 1 (HIV-1) and sexually transmitted diseases in a population of sex workers in Mombasa, Kenya. In total, 657 HIV-1-seronegative women were enrolled and followed at monthly intervals. At baseline, only 26% of women were colonized with Lactobacillus species. During follow-up, absence of vaginal lactobacilli on culture was associated with an increased risk of acquiring HIV-1 infection (hazard ratio [HR], 2.0; 95% confidence interval [CI], 1.2-3.5) and gonorrhea (HR, 1.7; 95% CI, 1.1-2.6), after controlling for other identified risk factors in separate multivariate models. Presence of abnormal vaginal flora on Gram's stain was associated with increased risk of both HIV-1 acquisition (HR, 1.9; 95% CI, 1.1-3.1) and Trichomonas infection (HR, 1.8; 95% CI, 1.3-2.4). Treatment of BV and promotion of vaginal colonization with lactobacilli should be evaluated as potential interventions to reduce a woman's risk of acquiring HIV-1, gonorrhea, and trichomoniasis.

Deficiency of Subsarcolemmal Mitochondria in Obesity and Type 2 Diabetes

Abstract: The current study addresses a novel hypothesis of subcellular distribution of mitochondrial dysfunction in skeletal muscle in type 2 diabetes. Vastus lateralis muscle was obtained by percutaneous biopsy from 11 volunteers with type 2 diabetes; 12 age-, sex-, and weight-matched obese sedentary nondiabetic volunteers; and 8 lean volunteers. Subsarcolemmal and intermyofibrillar mitochondrial fractions were isolated by differential centrifugation and digestion techniques. Overall electron transport chain activity was similar in type 2 diabetic and obese subjects, but subsarcolemmal mitochondria electron transport chain activity was reduced in type 2 diabetic subjects (0.017 ± 0.003 vs. 0.034 ± 0.007 units/mU creatine kinase [CK], P = 0.01) and sevenfold reduced compared with lean subjects ( P < 0.01). Electron transport chain activity in intermyofibrillar mitochondria was similar in type 2 diabetic and obese subjects, though reduced compared with lean subjects. A reduction in subsarcolemmal mitochondria was confirmed by transmission electron microscopy. Although mtDNA was lower in type 2 diabetic and obese subjects, the decrement in electron transport chain activity was proportionately greater, indicating functional impairment. Because of the potential importance of subsarcolemmal mitochondria for signal transduction and substrate transport, this deficit may contribute to the pathogenesis of muscle insulin resistance in type 2 diabetes.

Why Do Firms Pay Dividends? International Evidence on the Determinants of Dividend Policy

Abstract: In the U.S., Canada, U.K., Germany, France, and Japan, the propensity to pay dividends is higher among larger, more profitable firms, and those for which retained earnings comprise a large fraction of total equity. Although there are hints of reductions in the propensity to pay dividends in most of the sample countries over the 1994 to 2002 period, they are driven by a failure of newly listed firms to initiate dividends when expected to do so. Dividend abandonment and the failure to initiate by existing nonpayers are economically unimportant except in Japan. Moreover, in each country, aggregate dividends have not declined and are concentrated among the largest, most profitable firms. Finally, outside of the U.S. there is little evidence of a systematic positive relation between relative prices of dividend paying and non-paying firms and the propensity to pay dividends. Overall, these findings cast doubt on signaling, clientele, and catering explanations for dividends, but support agency cost-based lifecycle theories.