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.

Radiographical spinopelvic parameters and disability in the setting of adult spinal deformity: a prospective multicenter analysis.

Abstract: Study design Prospective multicenter study evaluating operative (OP) versus nonoperative (NONOP) treatment for adult spinal deformity (ASD). Objective Evaluate correlations between spinopelvic parameters and health-related quality of life (HRQOL) scores in patients with ASD. Summary of background data Sagittal spinal deformity is commonly defined by an increased sagittal vertical axis (SVA); however, SVA alone may underestimate the severity of the deformity. Spinopelvic parameters provide a more complete assessment of the sagittal plane but only limited data are available that correlate spinopelvic parameters with disability. METHODS.: Baseline demographic, radiographical, and HRQOL data were obtained for all patients enrolled in a multicenter consecutive database. Inclusion criteria were: age more than 18 years and radiographical diagnosis of ASD. Radiographical evaluation was conducted on the frontal and lateral planes and HRQOL questionnaires (Oswestry Disability Index [ODI], Scoliosis Research Society-22r and Short Form [SF]-12) were completed. Radiographical parameters demonstrating highest correlation with HRQOL values were evaluated to determine thresholds predictive of ODI more than 40. Results Four hundred ninety-two consecutive patients with ASD (mean age, 51.9 yr) were enrolled. Patients from the OP group (n = 178) were older (55 vs. 50.1 yr, P Conclusion ASD is a disabling condition. Prospective analysis of consecutively enrolled patients with ASD demonstrated that PT and PI-LL combined with SVA can predict patient disability and provide a guide for patient assessment for appropriate therapeutic decision making. Threshold values for severe disability (ODI > 40) included: PT 22° or more, SVA 47 mm or more, and PI - LL 11° or more.

Statistical tests for presence of cyclostationarity

Abstract: The presence of kth-order cyclostationarity is defined in terms of nonvanishing cyclic-cumulants or polyspectra. Relying upon the asymptotic normality and consistency of kth-order cyclic statistics, asymptotically optimal /spl chi//sup 2/ tests are developed to detect the presence of cycles in the kth-order cyclic cumulants or polyspectra, without assuming any specific distribution on the data. Constant false alarm rate tests are derived in both time- and frequency-domain and yield consistent estimates of possible cycles present in the kth-order cyclic statistics. Explicit algorithms for k/spl les/4 are discussed. Existing approaches are rather empirical and deal only with k/spl les/2 case. Simulation results are presented to confirm the performance of the given tests. >

The multifarious, multireplicon Burkholderia cepacia complex

Abstract: The Burkholderia cepacia complex (Bcc) is a collection of genetically distinct but phenotypically similar bacteria that are divided into at least nine species. Bcc bacteria are found throughout the environment, where they can have both beneficial and detrimental effects on plants and some members can also degrade natural and man-made pollutants. Bcc bacteria are now recognized as important opportunistic pathogens that can cause variable lung infections in cystic fibrosis patients, which result in asymptomatic carriage, chronic infection or 'cepacia syndrome', which is characterized by a rapid decline in lung function that can include invasive disease. Here we highlight the unique characteristics of the Bcc, focusing on the factors that determine virulence.

IPO Pricing in the Dot‐com Bubble

Abstract: IPO underpricingreached astronomical levels during1999 and 2000.We show that the regime shift in initial returns and other elements of pricing behavior can be at least partially accounted for by marked changes in pre-IPO ownership structure and insider sellingbehavior over the period, which reduced key decision makers’ incentives to control underpricing. After controlling for these changes, the diierence in underpricing between 1999 and 2000 and the precedingthree years is much reduced. Our results sug g est that it was ¢rm characteristics that were unique duringthe ‘‘dot-com bubble’’and that pricing behavior followed from incentives created by these characteristics. IN 1996, FIRST-DAY RETURNS on initial public oierings (IPOs) averaged about 17 percent (median: 10 percent). In 1999, ¢rst-day returns averaged 73 percent (median: 40 percent) before taperingoi to 58 percent (median: 30 percent) in 2000. Internet IPOs averaged a stunning 89 percent (median: 57 percent) during 1999 and 2000. These average returns dwarf those from earlier periods and are the most widely recognized feature of what is now commonly referred to as the ‘‘dot-com bubble’’. 1 Existingexplanations for the initial return behavior of IPOs focus in larg e part on informational frictions that arise amongthe various parties to the transaction. 2 Although it is conceivable that informational frictions became more severe duringthe dot-com bubble, it strains belief that even collectively this body of theory can account for the profound change in market behavior. With this in mind, Loughran and Ritter (2001) conjecture that issuers grew complacent