2,052 research outputs found
Biomechanical demands differentiate transitioning vs. continuous stair ascent gait in older women
Background Stair ascent mechanics change with age, but little is known about the differing functional demands of transitioning and continuous ascent. Work investigating the risky transition from gait to ascent is sparse, and the strategies that older adults adopt to achieve these demanding tasks have not been investigated. Methods This study compared the biomechanics of a 2-step transitional (floor-to-step2) and continuous ascent cycle (step1-to-step3) and investigated the role of limb preference in relation to dynamometer-derived knee strength during this transition. A biomechanical analysis of 36 women (60–83 years) ascending a 3-step staircase was conducted. Findings The 2-step transitioning cycle was completed quicker, with a larger range of motion, increased forces, larger knee flexor and dorsiflexor moments and ankle powers (P ≤ 0.05), but reduced hip and knee flexion, smaller hip extensor moments and hip and knee powers compared to continuous ascent. During the transition, 44% of the participants demonstrated a consistent limb preference. In these cases large between-limb extensor strength differences existed (13.8%) and 71% of these participants utilised the stronger limb to execute the 2-step transitional cycle. Interpretation The preferential stronger-limb 2-step transitioning strategy conflicts with previous recommendations of a stronger lead limb for frail/asymmetric populations. Our findings suggest that most healthy older women with large between-limb differences utilise the stronger limb to achieve the considerable propulsion required to redirect momentum during the 2-step transition. The biomechanical demands of ascent, relative to limb strength, can inform exercise programmes by targeting specific muscle groups to help older adults maintain/improve general functioning
Cerebro-spinal disease and its relation to the optic nerve: a critical review
In this review the optic nerve is interpretated as that part of the optic pathway which lies between the chiasm and the retina. The review is limited to a consideration of the conditions of this part of the visual tract
Lightcurve Classification in Massive Variability Surveys II: Transients towards the Large Magellanic Cloud
Automatic classification of variability is now possible with tools like
neural networks. Here, we present two neural networks for the identification of
microlensing events -- the first discriminates against variable stars and the
second against supernovae. The inputs to the networks include parameters
describing the shape and the size of the lightcurve, together with colour of
the event. The network computes the posterior probability of microlensing,
together with an estimate of the likely error. An algorithm is devised for
direct calculation of the microlensing rate from the output of the neural
networks. We present a new analysis of the microlensing candidates towards the
Large Magellanic Cloud (LMC). The neural networks confirm the microlensing
nature of only 7 of the possible 17 events identified by the MACHO experiment.
This suggests that earlier estimates of the microlensing optical depth towards
the LMC may have been overestimated. A smaller number of events is consistent
with the assumption that all the microlensing events are caused by the known
stellar populations in the outer Galaxy/LMC.Comment: 11 pages, MNRAS, in pres
Key dating features for timber-framed dwellings in Surrey
This article is made available through the Brunel Open Access Publishing Fund. Copyright @ The Vernacular Architecture Group 2013. MORE OpenChoice articles are open access and distributed under the terms of the Creative Commons Attribution License 3.0.The main component of the Surrey Dendrochronology Project is the accurate dating of 177 ‘dwellings’, nearly all by tree-ring analysis. The dates are used to establish date ranges for 52 ‘key features’, which cover many aspects of timber-framing from building type to details of carpentry. It is shown that changes of method and fashion were in many cases surprisingly rapid, almost abrupt in historical terms. Previous dating criteria for timber-framed dwellings in the county have been refined and new criteria introduced. Clusters of change from the 1440s and the 1540s are shown and some possible historical links suggested.The Heritage Lottery Fund, the Domestic Buildings Research Group (Surrey), the Surrey Archaeological Society and the historical societies of Charlwood, Farnham and Nutfield
Biomechanical demands of the 2-step transitional gait cycles linking level gait and stair descent gait in older women
Stair descent is an inherently complex form of locomotion posing a high falls risk for older adults, specifically when negotiating the transitional gait cycles linking level gait and descent. The aim of this study was to enhance our understanding of the biomechanical demands by comparing the demands of these transitions. Lower limb kinematics and kinetics of the 2-step transitions linking level and descent gait at the top (level-to-descent) and the bottom (descent-to-level) of the staircase were quantified in 36 older women with no falls history. Despite undergoing the same vertical displacement (2-steps), the following significant (p<.05) differences were observed during the top transition compared to the bottom transition: reduced step velocity; reduced hip extension and increased ankle dorsiflexion (late stance/pre-swing); reduced ground reaction forces, larger knee extensor moments and powers (absorption; late stance); reduced ankle plantarflexor moments (early and late stance) and increased ankle powers (mid-stance). Top transition biomechanics were similar to those reported previously for continuous descent. Kinetic differences at the knee and ankle signify the contrasting and prominent functions of controlled lowering during the top transition and forward continuance during the bottom transition. The varying musculoskeletal demands encountered during each functional sub-task should be addressed in falls prevention programmes with elderly populations where the greatest clinical impact may be achieved. Knee extensor eccentric power through flexion exercises would facilitate a smooth transition at the top and improving ankle plantarflexion strength during single and double limb stance activities would ease the transition into level gait following continuous descent
Practice to Policy: Clinical Psychologists' Experiences of Macro-Level Work
Aims: Many clinical psychologists have ventured beyond therapeutic and assessment roles to undertake public policy work. However, little research has systematically examined clinical psychologists’ roles in policy work and the implications of such work for the profession. This qualitative study examined the influences, processes, skills and knowledge underpinning policy work by clinical psychologists, and the challenges and facilitators encountered. /
Method: Participants were 37 UK clinical psychologists, from a broad spectrum of specialties, who had engaged in public policy work. They were selected by purposive sampling and snowballing to take part in a semi-structured interview about their experiences of policy work and social action. Transcripts were analyzed using Thematic Analysis. /
Results: The analysis yielded six themes, grouped into two domains: (1) ’Getting There’, describing participants’ professional journeys to policy work, including early influences and career paths, and (2) ‘Being There’ describing their experiences of working in this way, the challenges and facilitators in the process, and the skills and knowledge upon which they drew. /
Conclusions: Clinical psychologists already possess core clinical and research skills that may potentially be adapted to work within broader political systems. However, they need to learn to use their existing skills in a different context, and also acquire some additional skills unique to policy-level work
Possible Cosmological Implications of the Quark-Hadron Phase Transition
We study the quark-hadron phase transition within an effective model of QCD,
and find that in a reasonable range of the main parameters of the model, bodies
with quark content between and 10 solar masses can have been formed
in the early universe. In addition, we show that a significant amount of
entropy is released during the transition. This may imply the existence of a
higher baryon number density than what is usually expected at temperatures
above the QCD scale. The cosmological QCD transition may then provide a natural
way for decreasing the high baryon asymmetry created by an Affleck-Dine like
mechanism down to the value required by primordial nucleosynthesis.Comment: 19 pages, LaTeX, 5 Postscript figures included. Submitted to Journal
of Physics
On the Availability of European Mean Sea Level Data
Over the past two years a major effort has been made to bring up-to-date the European Mean Sea Level (MSL) data set with the result that significant updates have been obtained from all European coastlines, except one, which are known to operate tide gauges. Several important historical time series, not hitherto included in the Permanent Service for Mean Sea Level (PSMSL) data bank, have also been acquired. The resulting total European MSL data set, which is available for analysis by any interested research worker, will be employed subsequently in extensive climatological and geological investigations of European MSL interannual variability and long-term trends. This report presents a review of the quantity and quality of available European MSL data with particular emphasis on the recently-obtained information
Relics of the Cosmological QCD Phase Transition
The abundance and size distribution of quark nuggets (QN), formed a few
microseconds after the big bang due to first order QCD phase transition in the
early universe, has been estimated. It appears that stable QNs could be a
viable candidate for cosmological dark matter. The evolution of baryon
inhomogeneity due to evaporated (unstable) QNs are also examined.Comment: To appear in Physical Review
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