Ohio State University

About: Ohio State University is a education organization based out in Columbus, Ohio, United States. It is known for research contribution in the topics: Population & Cancer. The organization has 102421 authors who have published 222715 publications receiving 8373403 citations. The organization is also known as: Ohio State & The Ohio State University.

Central Masses and Broad-Line Region Sizes of Active Galactic Nuclei. I. Comparing the Photoionization and Reverberation Techniques

Abstract: The masses and emission-line region sizes of active galactic nuclei (AGNs) can be measured by "reverberation-mapping" techniques, and we use these results to calibrate similar determinations made by photoionization models of the AGN line-emitting regions. Reverberation mapping uses the light travel-time delayed emission-line response to continuum variations to determine the size and kinematics of the emission-line region. We compile a sample of 17 Seyfert 1 galaxies and two quasars with reliable reverberation and spectroscopy data, twice the number available previously. The data provide strong evidence that the broad-line region (BLR) size (as measured by the lag of the emission-line luminosity after changes in the continuum) and the emission-line width measure directly the central mass: the virial assumption is tested with long-term UV and optical monitoring data on NGC 5548. Two methods are used to estimate the distance of the broad emission-line region from the ionizing source: the photoionization method (which is available for many AGNs but has large intrinsic uncertainties) and the reverberation method (which gives very reliable distances but is available for only a few objects). The distance estimate is combined with the velocity dispersion, derived from the broad Hβ line width (in the photoionization method) or from the variable part (rms) of the line profile, in the reverberation-rms method, to estimate the virial mass. Comparing the central masses calculated with the reverberation-rms method to those calculated using a photoionization model, we find a highly significant, nearly linear correlation. This provides a calibration of the photoionization method on the objects with presently available reverberation data, which should enable mass estimates for all AGNs with measured Hβ line width. We find that the correlation between the masses is significantly better than the correlation between the corresponding BLR sizes calculated by the two methods, which further supports the conclusion that both methods measure the mass of the central black hole . Comparing the BLR sizes given by the two methods also enables us to estimate the ionizing EUV luminosity Lion, which is not directly observable. Typically it is 10 times the monochromatic luminosity at 5100 A (Lv). The Eddington ratio for the objects in our sample is in the range Lv/LEdd ~ 0.001-0.03 and Lion/LEdd ≈ 0.01-0.3.

A Pooled Analysis of Vitamin D Dose Requirements for Fracture Prevention

Abstract: BACKGROUND: The results of meta-analyses examining the relationship between vitamin D supplementation and fracture reduction have been inconsistent. METHODS: We pooled participant-level data from 11 double-blind, randomized, controlled trials of oral vitamin D supplementation (daily, weekly, or every 4 months), with or without calcium, as compared with placebo or calcium alone in persons 65 years of age or older. Primary end points were the incidence of hip and any nonvertebral fractures according to Cox regression analyses, with adjustment for age group, sex, type of dwelling, and study. Our primary aim was to compare data from quartiles of actual intake of vitamin D (including each individual participant's adherence to the treatment and supplement use outside the study protocol) in the treatment groups of all trials with data from the control groups. RESULTS: We included 31,022 persons (mean age, 76 years; 91% women) with 1111 incident hip fractures and 3770 nonvertebral fractures. Participants who were randomly assigned to receive vitamin D, as compared with those assigned to control groups, had a nonsignificant 10% reduction in the risk of hip fracture (hazard ratio, 0.90; 95% confidence interval [CI], 0.80 to 1.01) and a 7% reduction in the risk of nonvertebral fracture (hazard ratio, 0.93; 95% CI, 0.87 to 0.99). By quartiles of actual intake, reduction in the risk of fracture was shown only at the highest intake level (median, 800 IU daily; range, 792 to 2000), with a 30% reduction in the risk of hip fracture (hazard ratio, 0.70; 95% CI, 0.58 to 0.86) and a 14% reduction in the risk of any nonvertebral fracture (hazard ratio, 0.86; 95% CI, 0.76 to 0.96). Benefits at the highest level of vitamin D intake were fairly consistent across subgroups defined by age group, type of dwelling, baseline 25-hydroxyvitamin D level, and additional calcium intake. CONCLUSIONS: High-dose vitamin D supplementation (≥800 IU daily) was somewhat favorable in the prevention of hip fracture and any nonvertebral fracture in persons 65 years of age or older. (Funded by the Swiss National Foundations and others.) Copyright © 2012 Massachusetts Medical Society.

microRNA-7 Inhibits the Epidermal Growth Factor Receptor and the Akt Pathway and Is Down-regulated in Glioblastoma

Abstract: microRNAs are noncoding RNAs inhibiting expression of numerous target genes, and a few have been shown to act as oncogenes or tumor suppressors. We show that microRNA-7 (miR-7) is a potential tumor suppressor in glioblastoma targeting critical cancer pathways. miR-7 potently suppressed epidermal growth factor receptor expression, and furthermore it independently inhibited the Akt pathway via targeting upstream regulators. miR-7 expression was down-regulated in glioblastoma versus surrounding brain, with a mechanism involving impaired processing. Importantly, transfection with miR-7 decreased viability and invasiveness of primary glioblastoma lines. This study establishes miR-7 as a regulator of major cancer pathways and suggests that it has therapeutic potential for glioblastoma. [Cancer Res 2008;68(10):3566–71]

Conceptualizing the Role and Influence of Student-Teacher Relationships on Children's Social and Cognitive Development

Abstract: The purpose of this article is to add to our current understanding of the social contexts of education by synthesizing research on the nature and influence of relationships between students and their teachers. I was guided by 3 questions. First, how have we conceptualized students' relationships with teachers? Second, how have our approaches to studying relationships shaped our understanding of the phenomenon? Third, looking across these different approaches to studying student-teacher relationships, what do we know about the nature and influence of student-teacher relationships developmentally? Specifically, I review in 3 broad themes the multiple conceptions, or approaches, to the study of student-teacher relationships. These include student-teacher relationships from attachment perspectives, from motivation perspectives, and from sociocultural perspectives. I view each approach a posing a critical question needing to be addressed conceptually, methodologically, and developmentally. Looking across appro...

Gender Differences in Emotion Expression in Children: A Meta-Analytic Review

Abstract: Emotion expression is an important feature of healthy child development that has been found to show gender differences. However, there has been no empirical review of the literature on gender and facial, vocal, and behavioral expressions of different types of emotions in children. The present study constitutes a comprehensive meta-analytic review of gender differences and moderators of differences in emotion expression from infancy through adolescence. We analyzed 555 effect sizes from 166 studies with a total of 21,709 participants. Significant but very small gender differences were found overall, with girls showing more positive emotions (g –.08) and internalizing emotions (e.g., sadness, anxiety, sympathy; g –.10) than boys, and boys showing more externalizing emotions (e.g., anger; g .09) than girls. Notably, gender differences were moderated by age, interpersonal context, and task valence, underscoring the importance of contextual factors in gender differences. Gender differences in positive emotions were more pronounced with increasing age, with girls showing more positive emotions than boys in middle childhood (g –.20) and adolescence (g –.28). Boys showed more externalizing emotions than girls at toddler/preschool age (g .17) and middle childhood (g .13) and fewer externalizing emotions than girls in adolescence (g –.27). Gender differences were less pronounced with parents and were more pronounced with unfamiliar adults (for positive emotions) and with peers/when alone (for externalizing emotions). Our findings of gender differences in emotion expression in specific contexts have important implications for gender differences in children’s healthy and maladaptive development.