17,938 research outputs found
Identifying Gaps and Setting Priorities for Employment and Training Research
The report summarizes recent workforce and employment related research, to identify current gaps in employment and training research and makes recommendations for future research processes and priorities that could better inform policy makers, practitioners, job seekers and employers. The report reviews workforce and related research funded by several federal agencies, including the US Departments of Labor, Education, Agriculture, Health and Human Services, and Housing and Urban Development, the National Science Foundation and other federal entities, as well as research undertaken by regional, state and local workforce agencies and philanthrophic organizations
Physical Activity Modulates Corticospinal Excitability of the Lower Limb in Young and Old Adults
Aging is associated with reduced neuromuscular function, which may be due in part to altered corticospinal excitability. Regular physical activity (PA) may ameliorate these age-related declines, but the influence of PA on corticospinal excitability is unknown. The purpose of this study was to determine the influence of age, sex, and PA on corticospinal excitability by comparing the stimulus-response curves of motor evoked potentials (MEP) in 28 young (22.4 ± 2.2 yr; 14 women and 14 men) and 50 old adults (70.2 ± 6.1 yr; 22 women and 28 men) who varied in activity levels. Transcranial magnetic stimulation was used to elicit MEPs in the active vastus lateralis muscle (10% maximal voluntary contraction) with 5% increments in stimulator intensity until the maximum MEP amplitude. Stimulus-response curves of MEP amplitudes were fit with a four-parameter sigmoidal curve and the maximal slope calculated (slopemax). Habitual PA was assessed with tri-axial accelerometry and participants categorized into either those meeting the recommended PA guidelines for optimal health benefits (\u3e10,000 steps/day, high-PA; n = 21) or those not meeting the guidelines (n = 41). The MEP amplitudes and slopemax were greater in the low-PA compared with the high-PA group (P \u3c 0.05). Neither age nor sex influenced the stimulus-response curve parameters (P \u3e 0.05), suggesting that habitual PA influenced the excitability of the corticospinal tract projecting to the lower limb similarly in both young and old adults. These findings provide evidence that achieving the recommended PA guidelines for optimal health may mediate its effects on the nervous system by decreasing corticospinal excitability
Stress Fractures of the Elbow in the Throwing Athlete: A Systematic Review.
Background: Stress fractures of the elbow are rare in throwing athletes and present a challenge from both a management and rehabilitation perspective. Although the incidence of stress fractures of the elbow is increasing, there is a lack of data in the literature focused on throwers.
Purpose: To evaluate studies regarding the management and outcomes of stress fractures of the elbow in throwing athletes.
Study Design: Systematic review; Level of evidence, 4.
Methods: A systematic review was conducted by searching the Scopus, PubMed, and Cochrane Library electronic databases to identify studies reporting on the management and outcomes of stress fractures in overhead-throwing athletes. Management data included nonoperative and operative modalities, and outcome data included return to play, encompassing the timing and level of activity. Studies were excluded if the stress fracture of the elbow was not a result of a sport injury attributed to throwing or if the study failed to report whether an athlete returned to play.
Results: Fourteen studies met the inclusion criteria and were included in this analysis. There were 52 patients in total (50 male, 2 female) with a mean age of 19.7 years (range, 13-29.1 years). The olecranon was the most common location of the stress fracture (51 patients; 98.1%), followed by the distal humerus (1 patient; 1.9%). The majority of patients (n = 40; 76.9%) were treated operatively. Of the 40 patients who were treated surgically, 14 (35.0%) underwent a period of conservative treatment preoperatively that ultimately failed because of persistent nonunion or continued elbow pain. A total of 50 patients (96.2%) returned to sport either at or above their preinjury level. Of the 2 patients (3.8%) who did not return to sport, 1 did not return because of continued elbow pain postoperatively, and the other was lost to follow-up. Complications occurred in 9 patients (17.3%), all of whom were treated surgically.
Conclusion: On the basis of this systematic review, the majority of elbow stress fractures were treated operatively and approximately one-third after a period of failed nonoperative management. The return-to-sport rate was high. Further, higher level studies are needed to optimize management and return-to-sport rates in this population
Forecasting Equicorrelation
We study the out-of-sample forecasting performance of several time-series models of equicorrelation, which is the average pairwise correlation between a number of assets. Building on the existing Dynamic Conditional Correlation and Linear Dynamic Equicorrelation models, we propose a model that uses proxies for equicorrelation based on high-frequency intraday data, and the level of equicorrelation implied by options prices. Using state-of-the-art statistical evaluation technology, we find that the use of both realized and implied equicorrelations outperform models that use daily data alone. However, the out-of-sample forecasting benefits of implied equicorrelation disappear when used in conjunction with the realized measures.Equicorrelation, Implied Correlation, Multivariate GARCH, DCC
Physical Activity Modulates Corticospinal Excitability of the Lower Limb in Young and Old Adults
Aging is associated with reduced neuromuscular function, which may be due in part to altered corticospinal excitability. Regular physical activity (PA) may ameliorate these age-related declines, but the influence of PA on corticospinal excitability is unknown. The purpose of this study was to determine the influence of age, sex, and PA on corticospinal excitability by comparing the stimulus-response curves of motor evoked potentials (MEP) in 28 young (22.4 ± 2.2 yr; 14 women and 14 men) and 50 old adults (70.2 ± 6.1 yr; 22 women and 28 men) who varied in activity levels. Transcranial magnetic stimulation was used to elicit MEPs in the active vastus lateralis muscle (10% maximal voluntary contraction) with 5% increments in stimulator intensity until the maximum MEP amplitude. Stimulus-response curves of MEP amplitudes were fit with a four-parameter sigmoidal curve and the maximal slope calculated (slopemax). Habitual PA was assessed with tri-axial accelerometry and participants categorized into either those meeting the recommended PA guidelines for optimal health benefits (\u3e10,000 steps/day, high-PA; n = 21) or those not meeting the guidelines (n = 41). The MEP amplitudes and slopemax were greater in the low-PA compared with the high-PA group (P \u3c 0.05). Neither age nor sex influenced the stimulus-response curve parameters (P \u3e 0.05), suggesting that habitual PA influenced the excitability of the corticospinal tract projecting to the lower limb similarly in both young and old adults. These findings provide evidence that achieving the recommended PA guidelines for optimal health may mediate its effects on the nervous system by decreasing corticospinal excitability
Local u'g'r'i'z' Standard Stars in the Chandra Deep Field-South
Because several observing programs are underway in various spectral regimes
to explore the Chandra Deep Field South (CDF-S), the value of local photometric
standards is obvious. As part of an NOAO Surveys Program to establish
u'g'r'i'z' standard stars in the southern hemisphere, we have observed the
central region of the CDF-S to create local standards for use by other
investigators using these filters. As a courtesy, we present the CDF-S
standards to the public now, although the main program will not finish until
mid-2005.Comment: Accepted by AJ (scheduled for October 2003 issue). 26 pages, 5
tables, 5 figures. High resolution version of Figure 7 available at
http://home.fnal.gov/~dtucker/Southern_ugriz/index.htm
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