4,892 research outputs found
Evaluation of the Clinimetric Properties of the Upper Limb Subscales of the Motor Assessment Scale Using a Rasch Analysis Model.
OBJECTIVES: To apply Rasch analysis to evaluate the psychometric properties of the composite score of the 3 upper limb subscales of the Motor Assessment Scale (UL-MAS) when administered in the acute/subacute phase post-stroke. DESIGN: Prospective data collection of UL-MAS scores. PARTICIPANTS: Eighty Eighty individuals a mean of 64.8 days (standard deviation 53.3; range 4-193 days) following the onset of unilateral stroke. METHODS: All UL-MAS test items were administered in 30 participants assessed longitudinally over 3 occasions, and in 50 participants assessed on a single occasion. These 140 observations were pooled to be evaluated using Rasch analysis. RESULTS: With the elimination of the wrist radial deviation test item, the UL-MAS demonstrated uni-dimensionality with no significant test item response bias. The test item difficulty hierarchy was validated in the Upper Arm and Hand Movements subscales, but not in the Advanced Hand Activities subscale. The acceptable floor (14%) and ceiling (9%) effects and the high Person Separation Reliability Index (0.96) indicated that the scale was appropriately targeted to discriminate statistically between groups of acute/subacute stroke participants with differing upper limb motor recovery. CONCLUSION: The findings support the psychometric properties of the composite UL-MAS score in this clinical population
Household decision-making about delivery in health facilities: evidence from Tanzania.
This study investigated how partners' perceptions of the healthcare system influence decisions about delivery-location in low-resource settings. A multistage population-representative sample was used in Kasulu district, Tanzania, to identify women who had given birth in the last five years and their partners. Of 826 couples in analysis, 506 (61.3%) of the women delivered in the home. In multivariate analysis, factors associated with delivery in a health facility were agreement of partners on the importance of delivering in a health facility and agreement that skills of doctors are better than those of traditional birth attendants. When partners disagreed, the opinion of the woman was more influential in determining delivery-location. Agreement of partners regarding perceptions about the healthcare system appeared to be an important driver of decisions about delivery-location. These findings suggest that both partners should be included in the decision-making process regarding delivery to raise rates of delivery at facility
Searching for Dark Matter at the LHC with a Mono-Z
We investigate a mono-Z process as a potential dark matter search strategy at
the LHC. In this channel a single Z boson recoils against missing transverse
momentum, attributed to dark matter particles, , which escape the
detector. This search strategy is related, and complementary to, monojet and
monophoton searches. For illustrative purposes we consider the process
in a toy dark matter model, where the Z boson is
emitted from either the initial state quarks, or from the internal propagator.
Among the signatures of this process will be a pair of muons with high pT that
reconstruct to the invariant mass of the Z, and large amounts of missing
transverse energy. Being a purely electroweak signal, QCD and other Standard
Model backgrounds are relatively easily removed with modest selection cuts. We
compare the signal to Standard Model backgrounds and demonstrate that, even for
conservative cuts, there exist regions of parameter space where the signal may
be clearly visible above background in future LHC data, allowing either new
discovery potential or the possibility of supplementing information about the
dark sector beyond that available from other observable channels.Comment: 11 pages, 13 figure
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Analyzing Postdisaster Surveillance Data: The Effect of the Statistical Method
Data from existing administrative databases and ongoing surveys or surveillance methods may prove indispensable after mass traumas as a way of providing information that may be useful to emergency planners and practitioners. The analytic approach, however, may affect exposure prevalence estimates and measures of association. We compare Bayesian hierarchical modeling methods to standard survey analytic techniques for survey data collected in the aftermath of a terrorist attack. Estimates for the prevalence of exposure to the terrorist attacks of September 11, 2001, varied by the method chosen. Bayesian hierarchical modeling returned the lowest estimate for exposure prevalence with a credible interval spanning nearly 3 times the range of the confidence intervals (CIs) associated with both unadjusted and survey procedures. Bayesian hierarchical modeling also returned a smaller point estimate for measures of association, although in this instance the credible interval was tighter than that obtained through survey procedures. Bayesian approaches allow a consideration of preexisting assumptions about survey data, and may offer potential advantages, particularly in the uncertain environment of postterrorism and disaster settings. Additional comparative analyses of existing data are necessary to guide our ability to use these techniques in future incidents
Gas Purity effect on GEM Performance in He and Ne at Low Temperatures
The performance of Gas Electron Multipliers (GEMs) in gaseous He, Ne, He+H2
and Ne+H2 was studied at temperatures in the range of 3-293 K. This paper
reports on previously published measurements and additional studies on the
effects of the purity of the gases in which the GEM performance is evaluated.
In He, at temperatures between 77 and 293 K, triple-GEM structures operate at
rather high gains, exceeding 1000. There is an indication that this high gain
is achieved through the Penning effect as a result of impurities in the gas. At
lower temperatures the gain-voltage characteristics are significantly modified
probably due to the freeze-out of these impurities. Double-GEM and single-GEM
structures can operate down to 3 K at gains reaching only several tens at a gas
density of about 0.5 g/l; at higher densities the maximum gain drops further.
In Ne, the maximum gain also drops at cryogenic temperatures. The gain drop in
Ne at low temperatures can be re-established in Penning mixtures of Ne+H2: very
high gains, exceeding 104, have been obtained in these mixtures at 30-77 K, at
a density of 9.2 g/l which corresponds to saturated Ne vapor density at 27 K.
The addition of small amounts of H2 in He also re-establishes large GEM gains
above 30 K but no gain was observed in He+H2 at 4 K and a density of 1.7 g/l
(corresponding to roughly one-tenth of the saturated vapor density). These
studies are, in part, being pursued in the development of two-phase He and Ne
detectors for solar neutrino detection.Comment: 4 pages, 7 figure
Laterality Differences in Cerebellar-Motor Cortex Connectivity
Lateralization of function is an important organizational feature of the motor system. Each effector is predominantly controlled by the contralateral cerebral cortex and the ipsilateral cerebellum. Transcranial magnetic stimulation studies have revealed hemispheric differences in the stimulation strength required to evoke a muscle response from the primary motor cortex (M1), with the dominant hemisphere typically requiring less stimulation than the nondominant. The current study assessed whether the strength of the connection between the cerebellum and M1 (CB-M1), known to change in association with motor learning, have hemispheric differences and whether these differences have any behavioral correlate. We observed, in right-handed individuals, that the connection between the right cerebellum and left M1 is typically stronger than the contralateral network. Behaviorally, we detected no lateralized learning processes, though we did find a significant effect on the amplitude of reaching movements across hands. Furthermore, we observed that the strength of the CB-M1 connection is correlated with the amplitude variability of reaching movements, a measure of movement precision, where stronger connectivity was associated with better precision. These findings indicate that lateralization in the motor system is present beyond the primary motor cortex, and points to an association between cerebellar M1 connectivity and movement execution
Reward-driven enhancements in motor control are robust to TMS manipulation
A wealth of evidence describes the strong positive impact that reward has on motor control at the behavioural level. However, surprisingly little is known regarding the neural mechanisms which underpin these effects, beyond a reliance on the dopaminergic system. In recent work, we developed a task that enabled the dissociation of the selection and execution components of an upper limb reaching movement. Our results demonstrated that both selection and execution are concommitently enhanced by immediate reward availability. Here, we investigate what the neural underpinnings of each component may be. To this end, we aimed to alter the cortical excitability of the ventromedial prefrontal cortex and supplementary motor area using continuous theta-burst transcranial magnetic stimulation (cTBS) in a within-participant design (N = 23). Both cortical areas are involved in determining an individual’s sensitivity to reward and physical effort, and we hypothesised that a change in excitability would result in the reward-driven effects on action selection and execution to be altered, respectively. To increase statistical power, participants were pre-selected based on their sensitivity to reward in the reaching task. While reward did lead to enhanced performance during the cTBS sessions and a control sham session, cTBS was ineffective in altering these effects. These results may provide evidence that other areas, such as the primary motor cortex or the premotor area, may drive the reward-based enhancements of motor performance
Multilocus sequence typing identifies an avian-like Chlamydia psittaci strain involved in equine placentitis and associated with subsequent human psittacosis
No abstract available
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