4,568 research outputs found

    Expanding the Circle: Essays in Honor of Joan E. Hemenway

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    Reviewed by Sandee Yarlott

    Wall turbulence control

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    A variety of wall turbulence control devices which were experimentally investigated are discussed; these include devices for burst control, alteration of outer flow structures, large eddy substitution, increased heat transfer efficiency, and reduction of wall pressure fluctuations. Control of pre-burst flow was demonstrated with a single, traveling surface depression which is phase-locked to elements of the burst production process. Another approach to wall turbulence control is to interfere with the outer layer coherent structures. A device in the outer part of a boundary layer was shown to suppress turbulence and reduce drag by opposing both the mean and unsteady vorticity in the boundary layer. Large eddy substitution is a method in which streamline curvature is introduced into the boundary layer in the form of streamwise vortices. Riblets, which were already shown to reduce turbulent drag, were also shown to exhibit superior heat transfer characteristics. Heat transfer efficiency as measured by the Reynolds Analogy Factor was shown to be as much as 36 percent greater than a smooth flat plate in a turbulent boundary layer. Large Eddy Break-Up (LEBU) which are also known to reduce turbulent drag were shown to reduce turbulent wall pressure fluctuation

    Analytic nuclear forces and molecular properties from full configuration interaction quantum Monte Carlo

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    Unbiased stochastic sampling of the one- and two-body reduced density matrices is achieved in full configuration interaction quantum Monte Carlo with the introduction of a second, "replica" ensemble of walkers, whose population evolves in imaginary time independently from the first, and which entails only modest additional computational overheads. The matrices obtained from this approach are shown to be representative of full configuration-interaction quality, and hence provide a realistic opportunity to achieve high-quality results for a range of properties whose operators do not necessarily commute with the hamiltonian. A density-matrix formulated quasi-variational energy estimator having been already proposed and investigated, the present work extends the scope of the theory to take in studies of analytic nuclear forces, molecular dipole moments and polarisabilities, with extensive comparison to exact results where possible. These new results confirm the suitability of the sampling technique and, where sufficiently large basis sets are available, achieve close agreement with experimental values, expanding the scope of the method to new areas of investigation.Comment: 11 page

    Maine’s Climate Yesterday, Today, and Tomorrow

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    Recent evidence suggests that climate change is occurring at an accelerated rate as a result of human-induced greenhouse gas emissions and associated pollutants. Based on a recently completed study, the authors describe the changes Maine’s climate is likely to undergo over the next century. They suggest that while reduction of greenhouse gases is crucial, Maine needs to be prepared to adapt to the impact that our already changing climate will have on various ecosystems and economic sectors within the stat

    Telerehabilitation services for stroke

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    Publisher version made available in accordance with the publisher's policy. This item is under embargo for a period of 12 months from the date of publication, in accordance with the publisher's policy. 'This review is published as a Cochrane Review in the Cochrane Database of Systematic Reviews 2013, Issue 12. Cochrane Reviews are regularly updated as new evidence emerges and in response to comments and criticisms, and the Cochrane Database of Systematic Reviews should be consulted for the most recent version of the Review.’Background Telerehabilitation is an alternative way of delivering rehabilitation services. Information and communication technologies are used to facilitate communication between the healthcare professional and the patient in a remote location. The use of telerehabilitation is becoming more viable as the speed and sophistication of communication technologies improve. However, it is currently unclear how effective this model of delivery is relative to rehabilitation delivered face-to-face. Objectives To determine whether the use of telerehabilitation leads to improved ability to perform activities of daily living amongst stroke survivors when compared with (1) in-person rehabilitation (when the clinician and the patient are at the same physical location and rehabilitation is provided face-to-face); or (2) no rehabilitation. Secondary objectives were to determine whether use of telerehabilitation leads to greater independence in self care and domestic life and improved mobility, health-related quality of life, upper limb function, cognitive function or functional communication when compared with in-person rehabilitation and no rehabilitation. Additionally, we aimed to report on the presence of adverse events, cost-effectiveness, feasibility and levels of user satisfaction associated with telerehabilitation interventions. Search methods We searched the Cochrane Stroke Group Trials Register (November 2012), the Cochrane Effective Practice and Organization of Care Group Trials Register (November 2012), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 11, 2012), MEDLINE (1950 to November 2012), EMBASE (1980 to November 2012) and eight additional databases. We searched trial registries, conference proceedings and reference lists. Selection criteria Randomised controlled trials (RCTs) of telerehabilitation in stroke. We included studies that compared telerehabilitation with in-person rehabilitation or no rehabilitation. In addition, we synthesised and described the results of RCTs that compared two different methods of delivering telerehabilitation services without an alternative group. We included rehabilitation programmes that used a combination of telerehabilitation and in-person rehabilitation provided that the greater proportion of intervention was provided via telerehabilitation. Data collection and analysis Two review authors independently identified trials on the basis of prespecified inclusion criteria, extracted data and assessed risk of bias. A third review author moderated any disagreements. The review authors contacted investigators to ask for missing information. Main results We included in the review 10 trials involving a total of 933 participants. The studies were generally small, and reporting quality was often inadequate, particularly in relation to blinding of outcome assessors and concealment of allocation. Selective outcome reporting was apparent in several studies. Study interventions and comparisons varied, meaning that in most cases, it was inappropriate to pool studies. Intervention approaches included upper limb training, lower limb and mobility retraining, case management and caregiver support. Most studies were conducted with people in the chronic phase following stroke. Primary outcome: no statistically significant results for independence in activities of daily living (based on two studies with 661 participants) were noted when a case management intervention was evaluated. Secondary outcomes: no statistically significant results for upper limb function (based on two studies with 46 participants) were observed when a computer programme was used to remotely retrain upper limb function. Evidence was insufficient to draw conclusions on the effects of the intervention on mobility, health-related quality of life or participant satisfaction with the intervention. No studies evaluated the cost-effectiveness of telerehabilitation. No studies reported on the occurrence of adverse events within the studies. Authors' conclusions We found insufficient evidence to reach conclusions about the effectiveness of telerehabilitation after stroke. Moreover, we were unable to find any randomised trials that included an evaluation of cost-effectiveness. Which intervention approaches are most appropriately adapted to a telerehabilitation approach remain unclear, as does the best way to utilise this approach

    Observation of Amounts of Movement Practice Provided during Stroke Rehabilitation

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    Objective To investigate how much movement practice occurred during stroke rehabilitation, and what factors might influence doses of practice provided. Design Observational survey of stroke therapy sessions. Setting Seven inpatient and outpatient rehabilitation sites. Participants We observed a convenience sample of 312 physical and occupational therapy sessions for people with stroke. Interventions Not applicable. Main Outcome Measures We recorded numbers of repetitions in specific movement categories and data on potential modifying factors (patient age, side affected, time since stroke, FIM item scores, years of therapist experience). Descriptive statistics were used to characterize amounts of practice. Correlation and regression analyses were used to determine whether potential factors were related to the amount of practice in the 2 important categories of upper extremity functional movements and gait steps. Results Practice of task-specific, functional upper extremity movements occurred in 51% of the sessions that addressed upper limb rehabilitation, and the average number of repetitions/session was 32 (95% confidence interval [CI]=20–44). Practice of gait occurred in 84% of sessions that addressed lower limb rehabilitation and the average number of gait steps/session was 357 (95% CI=296–418). None of the potential factors listed accounted for significant variance in the amount of practice in either of these 2 categories. Conclusions The amount of practice provided during poststroke rehabilitation is small compared with animal models. It is possible that current doses of task-specific practice during rehabilitation are not adequate to drive the neural reorganization needed to promote function poststroke optimally
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