1,464 research outputs found
Unusually large polarizabilities and "new" atomic states in Ba
Electric polarizabilities of four low-J even-parity states and three low-J
odd-parity states of atomic barium in the range to $36,000\
^{-1}6s8p
^3P_{0,2}$ is suggested.Comment: 29 pages, 12 figure
Nonlinear magneto-optical rotation with frequency-modulated light in the geophysical field range
Recent work investigating resonant nonlinear magneto-optical rotation (NMOR)
related to long-lived (\tau\ts{rel} \sim 1 {\rm s}) ground-state atomic
coherences has demonstrated potential magnetometric sensitivities exceeding
for small () magnetic
fields. In the present work, NMOR using frequency-modulated light (FM NMOR) is
studied in the regime where the longitudinal magnetic field is in the
geophysical range (), of particular interest for many
applications. In this regime a splitting of the FM NMOR resonance due to the
nonlinear Zeeman effect is observed. At sufficiently high light intensities,
there is also a splitting of the FM NMOR resonances due to ac Stark shifts
induced by the optical field, as well as evidence of alignment-to-orientation
conversion type processes. The consequences of these effects for FM-NMOR-based
atomic magnetometry in the geophysical field range are considered.Comment: 8 pages, 8 figure
Consensus based framework for digital mobility monitoring
Digital mobility assessment using wearable sensor systems has the potential to capture walking performance in a patient's natural environment. It enables monitoring of health status and disease progression and evaluation of interventions in real-world situations. In contrast to laboratory settings, real-world walking occurs in non-conventional environments and under unconstrained and uncontrolled conditions. Despite the general understanding, there is a lack of agreed definitions about what constitutes real-world walking, impeding the comparison and interpretation of the acquired data across systems and studies. The goal of this study was to obtain expert-based consensus on specific aspects of real-world walking and to provide respective definitions in a common terminological framework. An adapted Delphi method was used to obtain agreed definitions related to real-world walking. In an online survey, 162 participants from a panel of academic, clinical and industrial experts with experience in the field of gait analysis were asked for agreement on previously specified definitions. Descriptive statistics was used to evaluate whether consent (> 75% agreement as defined a priori) was reached. Of 162 experts invited to participate, 51 completed all rounds (31.5% response rate). We obtained consensus on all definitions ("Walking"> 90%, "Purposeful"> 75%, "Real-world"> 90%, "Walking bout"> 80%, "Walking speed"> 75%, "Turning"> 90% agreement) after two rounds. The identification of a consented set of realworld walking definitions has important implications for the development of assessment and analysis protocols, as well as for the reporting and comparison of digital mobility outcomes across studies and systems. The definitions will serve as a common framework for implementing digital and mobile technologies for gait assessment and are an important link for the transition from supervised to unsupervised gait assessment
A multicentre, randomised controlled trial of PDSAFE, a physiotherapist-delivered fall prevention programme for people with Parkinsonâs
This is the author accepted manuscript. The final version is available from BMJ Publishing Group via the DOI in this record.Objective: To estimate the effect of a physiotherapist-delivered fall-prevention programme for people with
Parkinsonâs (PwP).
Methods: People at risk of falls with confirmed Parkinsonâs were recruited to this multi-centre, pragmatic,
investigator blind, individually randomised controlled trial with pre-specified sub-group analyses. 474 PwP
(Hoehn and Yahr 1-4) were randomised: 238 allocated to a physiotherapy programme and 236 to control.
All participants had routine care; the control group received a DVD about Parkinsonâs and single advice
session at trial completion. The intervention group (PDSAFE) had an individually tailored, progressive
home-based fall-avoidance strategy training programme with balance and strengthening exercises.
The primary outcome was risk of repeat-falling, collected by self-report monthly diaries, 0 to 6 months
post-randomisation. Secondary outcomes included, Mini-BESTest for balance, chair stand test, Falls
Efficacy, freezing of gait, health related quality of life (Euroqol EQ-5D), Geriatric Depression Scale, Physical
Activity Scale for the Elderly and Parkinsonâs disease Questionnaire, fractures and rate of near-falling.
Results: Average age, 72 years and 266 (56%) were men. By 6 months 116 (55%) of the control group, and
125 (61.5%) of the intervention group reported repeat falls (controlled odds ratio 1.21, 95% confidence
interval 0.74 to 1.98, P=0.447). Secondary sub-group analyses suggested a different response to the
intervention between moderate and severe disease severity groups. Balance, falls efficacy and chair stand
time improved with near-falls reduced in the intervention arm.
Conclusion: PDSAFE did not reduce falling in this pragmatic trial of PwP. Other functional tasks improved
and reduced fall rates were apparent among those with moderate disease.Department of HealthNational Institute for Health Research (NIHR
Vacuum Squeezing in Atomic Media via Self-Rotation
When linearly polarized light propagates through a medium in which
elliptically polarized light would undergo self-rotation, squeezed vacuum can
appear in the orthogonal polarization. A simple relationship between
self-rotation and the degree of vacuum squeezing is developed. Taking into
account absorption, we find the optimum conditions for squeezing in any medium
that can produce self-rotation. We then find analytic expressions for the
amount of vacuum squeezing produced by an atomic vapor when light is
near-resonant with a transition between various low-angular-momentum states.
Finally, we consider a gas of multi-level Rb atoms, and analyze squeezing for
light tuned near the D-lines under realistic conditions.Comment: 10 pages, 6 figures; Submitted to PR
Nonlinear magneto-optical rotation of frequency-modulated light resonant with a low-J transition
A low-light-power theory of nonlinear magneto-optical rotation of
frequency-modulated light resonant with a J=1->J'=0 transition is presented.
The theory is developed for a Doppler-free transition, and then modified to
account for Doppler broadening and velocity mixing due to collisions. The
results of the theory are shown to be in qualitative agreement with
experimental data obtained for the rubidium D1 line.Comment: 11 pages, 5 figures, v.2 edited for clarit
Great Expectations: Voluntary Sports Clubs and Their Role in Delivering National Policy for English Sport
âThe original publication is available at www.springerlink.comâ. Copyright International Society for Third-Sector Research and The Johns Hopkins University. DOI: 10.1007/s11266-009-9095-yVoluntary sports clubs (VSCs) account for about a quarter of all volunteering in England. The volunteers work in a mutual aid, self-production, self-consumption system whose main purpose is identifying and nurturing high-level performers. But the new HMG/Sport England strategies leading to London 2012 expects volunteers to make a major contribution to sustaining and extending participation. The study utilized six focus group sessions with a total of 36 officials and members of 36 clubs across the six counties of Eastern England to assess whether and to what extent government policy objectives can be delivered through the voluntary sector. The study focused on the perceptions and attitudes of club members about being expected to serve public policy and the current pressures they and their clubs face. The results lead the authors to question the appropriateness, sensitivity, and feasibility of current sport policy, particularly the emphasis on VSCs as policy implementers.Peer reviewe
Wearable Haptic Devices for Gait Re-education by Rhythmic Haptic Cueing
This research explores the development and evaluation of wearable haptic devices for gait sensing and rhythmic haptic cueing in the context of gait re-education for people with neurological and neurodegenerative conditions. Many people with long-term neurological and neurodegenerative conditions such as Stroke, Brain Injury, Multiple Sclerosis or Parkinsonâs disease suffer from impaired walking gait pattern. Gait improvement can lead to better fluidity in walking, improved health outcomes, greater independence, and enhanced quality of life. Existing lab-based studies with wearable devices have shown that rhythmic haptic cueing can cause immediate improvements to gait features such as temporal symmetry, stride length, and walking speed. However, current wearable systems are unsuitable for self-managed use for in-the-wild applications with people having such conditions. This work aims to investigate the research question of how wearable haptic devices can help in long-term gait re-education using rhythmic haptic cueing. A longitudinal pilot study has been conducted with a brain trauma survivor, providing rhythmic haptic cueing using a wearable haptic device as a therapeutic intervention for a two-week period. Preliminary results comparing pre and post-intervention gait measurements have shown improvements in walking speed, temporal asymmetry, and stride length. The pilot study has raised an array of issues that require further study. This work aims to develop and evaluate prototype systems through an iterative design process to make possible the self-managed use of such devices in-the-wild. These systems will directly provide therapeutic intervention for gait re-education, offer enhanced information for therapists, remotely monitor dosage adherence and inform treatment and prognoses over the long-term. This research will evaluate the use of technology from the perspective of multiple stakeholders, including clinicians, carers and patients. This work has the potential to impact clinical practice nationwide and worldwide in neuro-physiotherapy
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