University of Virginia

About: University of Virginia is a education organization based out in Charlottesville, Virginia, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 52543 authors who have published 113268 publications receiving 5220506 citations. The organization is also known as: U of V & UVa.

Intelligence: New findings and theoretical developments.

Abstract: We review new findings and new theoretical developments in the field of intelligence New findings include the following: (a) Heritability of IQ varies significantly by social class (b) Almost no genetic polymorphisms have been discovered that are consistently associated with variation in IQ in the normal range (c) Much has been learned about the biological underpinnings of intelligence (d) "Crystallized" and "fluid" IQ are quite different aspects of intelligence at both the behavioral and biological levels (e) The importance of the environment for IQ is established by the 12-point to 18-point increase in IQ when children are adopted from working-class to middle-class homes (f) Even when improvements in IQ produced by the most effective early childhood interventions fail to persist, there can be very marked effects on academic achievement and life outcomes (g) In most developed countries studied, gains on IQ tests have continued, and they are beginning in the developing world (h) Sex differences in aspects of intelligence are due partly to identifiable biological factors and partly to socialization factors (i) The IQ gap between Blacks and Whites has been reduced by 033 SD in recent years We report theorizing concerning (a) the relationship between working memory and intelligence, (b) the apparent contradiction between strong heritability effects on IQ and strong secular effects on IQ, (c) whether a general intelligence factor could arise from initially largely independent cognitive skills, (d) the relation between self-regulation and cognitive skills, and (e) the effects of stress on intelligence

Frequency of bowel movements and the future risk of Parkinson’s disease

Abstract: Background: Constipation is frequent in PD, although its onset in relation to clinical PD has not been well described. Demonstration that constipation can precede clinical PD could provide important clues to understanding disease progression and etiology. The purpose of this report is to examine the association between the frequency of bowel movements and the future risk of PD. Methods: Information on the frequency of bowel movements was collected from 1971 to 1974 in 6790 men aged 51 to 75 years without PD in the Honolulu Heart Program. Follow-up for incident PD occurred over a 24-year period. Results: Ninety-six men developed PD an average of 12 years into follow-up. Age-adjusted incidence declined consistently from 18.9/10,000 person-years in men with 2/day ( p = 0.005). After adjustment for age, pack-years of cigarette smoking, coffee consumption, laxative use, jogging, and the intake of fruits, vegetables, and grains, men with p = 0.007). The risk of PD in men with p = 0.001) and to a 4.5-fold excess versus men with >2/day (95% CI: 1.2, 16.9; p = 0.025). Conclusions: Findings indicate that infrequent bowel movements are associated with an elevated risk of future PD. Further study is needed to determine whether constipation is part of early PD processes or is a marker of susceptibility or environmental factors that may cause PD.

Identifying conformational changes with site-directed spin labeling.

Abstract: Site-direct spin labeling combined with electron paramagnetic resonance (EPR) spectroscopy is a powerful tool for detecting structural changes in proteins. This review provides examples that illustrate strategies for interpreting the data in terms of specific rearrangements in secondary and tertiary structure. The changes in the mobility and solvent accessibility of the spin label side chains, and in the distances between spin labels, report (i) rigid body motions of alpha-helices and beta-strands (ii) relative movements of domains and (iii) changes in secondary structure. Such events can be monitored in the millisecond time-scale, making it possible to follow structural changes during function. There is no upper limit to the size of proteins that can be investigated, and only 50-100 picomoles of protein are required. These features make site-directed spin labeling an attractive approach for the study of structure and dynamics in a wide range of systems.

Effectiveness and Limitations of β-Blocker Therapy in Congenital Long-QT Syndrome

Abstract: Background—β-blockers are routinely prescribed in congenital long-QT syndrome (LQTS), but the effectiveness and limitations of β-blockers in this disorder have not been evaluated. Methods and Results—The study population comprised 869 LQTS patients treated with β-blockers. Effectiveness of β-blockers was analyzed during matched periods before and after starting β-blocker therapy, and by survivorship methods to determine factors associated with cardiac events while on prescribed β-blockers. After initiation of β-blockers, there was a significant (P<0.001) reduction in the rate of cardiac events in probands (0.97±1.42 to 0.31±0.86 events per year) and in affected family members (0.26±0.84 to 0.15±0.69 events per year) during 5-year matched periods. On-therapy survivorship analyses revealed that patients with cardiac symptoms before β-blockers (n=598) had a hazard ratio of 5.8 (95% CI, 3.7 to 9.1) for recurrent cardiac events (syncope, aborted cardiac arrest, or death) during β-blocker therapy compared with ...

Genome evolution in the allotetraploid frog Xenopus laevis

Abstract: To explore the origins and consequences of tetraploidy in the African clawed frog, we sequenced the Xenopus laevis genome and compared it to the related diploid X. tropicalis genome. We characterize the allotetraploid origin of X. laevis by partitioning its genome into two homoeologous subgenomes, marked by distinct families of 'fossil' transposable elements. On the basis of the activity of these elements and the age of hundreds of unitary pseudogenes, we estimate that the two diploid progenitor species diverged around 34 million years ago (Ma) and combined to form an allotetraploid around 17-18 Ma. More than 56% of all genes were retained in two homoeologous copies. Protein function, gene expression, and the amount of conserved flanking sequence all correlate with retention rates. The subgenomes have evolved asymmetrically, with one chromosome set more often preserving the ancestral state and the other experiencing more gene loss, deletion, rearrangement, and reduced gene expression.