1,344 research outputs found
Uniaxial strain control of spin-polarization in multicomponent nematic order of BaFeAs
The iron-based high temperature superconductors exhibit a rich phase diagram
reflecting a complex interplay between spin, lattice, and orbital degrees of
freedom [1-4]. The nematic state observed in many of these compounds epitomizes
this complexity, by entangling a real-space anisotropy in the spin fluctuation
spectrum with ferro-orbital order and an orthorhombic lattice distortion [5-7].
A more subtle and much less explored facet of the interplay between these
degrees of freedom arises from the sizable spin-orbit coupling present in these
systems, which translates anisotropies in real space into anisotropies in spin
space. Here, we present a new technique enabling nuclear magnetic resonance
under precise tunable strain control, which reveals that upon application of a
tetragonal symmetry-breaking strain field, the magnetic fluctuation spectrum in
the paramagnetic phase of BaFeAs also acquires an anisotropic
response in spin-space. Our results unveil a hitherto uncharted internal spin
structure of the nematic order parameter, indicating that similar to liquid
crystals, electronic nematic materials may offer a novel route to
magneto-mechanical control.Comment: 11 pages, 5 figure
A review of the accuracy and utility of motion sensors to measure physical activity of frail older hospitalised patients.
The purpose of this review was to examine the utility and accuracy of commercially available motion sensors to measure step-count and time spent upright in frail older hospitalized patients. A database search (CINAHL and PubMed, 2004â2014) and a further hand search of papersâ references yielded 24 validation studies meeting the inclusion criteria. Fifteen motion sensors (eight pedometers, six accelerometers, and one sensor systems) have been tested in older adults. Only three have been tested in hospital patients, two of which detected postures and postural changes accurately, but none estimated step-count accurately. Only one motion sensor remained accurate at speeds typical of frail older hospitalized patients, but it has yet to be tested in this cohort. Time spent upright can be accurately measured in the hospital, but further validation studies are required to determine which, if any, motion sensor can accurately measure step-count
Palliative care and Parkinson's disease : meeting summary and recommendations for clinical research
Introduction: Palliative care is an approach to caring for patients and families affected by serious illnesses that focuses on the relief of suffering through the management of medical symptoms, psychosocial issues, advance care planning and spiritual wellbeing. Over the past decade there has been an emerging clinical and research interest in the application of palliative care approaches to Parkinsonâs disease (PD) and outpatient palliative care services are now offered by several movement disorders centers. Methods: An International Working Group Meeting on PD and Palliative Care supported by the Parkinsonâs Disease Foundation was held in October 2015 to review the current state of the evidence and to make recommendations for clinical research and practice. Results: Topics included: 1) Defining palliative care for PD; 2) Lessons from palliative care for heart failure and other chronic illnesses; 3) Patient and caregiver Needs; 4) Needs assessment tools; 5) Intervention strategies; 6) Predicting prognosis and hospice referrals; 7) Choice of appropriate outcome measures; 8) Implementation, dissemination and education research; and 9) Need for research collaborations. We provide an overview of these discussions, summarize current evidence and practices, highlight gaps in our knowledge and make recommendations for future research. Conclusions: Palliative Care for PD is a rapidly growing area which holds great promise for improving outcomes for PD patients and their caregivers. While clinical research in this area can build from lessons learned in other diseases, there is a need for observational, methodological and interventional research to address the unique needs of PD patients and caregivers
Exploring the physical activity and screen-viewing-related knowledge, training, and self-efficacy of early childhood education candidates
Background: Early childhood educators greatly influence young children\u27s physical activity and screen-viewing behaviours in childcare. However, educators have requested additional training in physical activity programming, and one logical place to provide this education is during their pre-service schooling. This study explored the physical activity and screen-viewing-related knowledge, training, and self-efficacy of early childhood education (ECE) candidates across Canada, to determine their confidence and ability to facilitate physical activity opportunities and limit screen-viewing among young children in childcare. Methods: Key program personnel at 61 (of 110) Canadian colleges/universities offering an ECE program agreed to participate in this cross-sectional study. An online survey (112 items; 9 domains), developed by experts using the Tailored Design Method, was administered via Qualtrics© to a sample of 1292 ECE candidates. Descriptive statistics, Mann-Whitney U-tests, and chi-square tests were used to report participant demographics and physical activity and screen-viewing-related knowledge (i.e., of physical activity and screen-viewing concepts), training (i.e., physical activity and screen-viewing courses/content received), and self-efficacy (i.e., to facilitate physical activity and limit screen-viewing in childcare) of candidates. Results: ECE candidates exhibited the least amount of knowledge regarding the impact of screen-viewing on physiological outcomes (i.e., blood pressure) in young children. Further, only 32.2 and 26.7% of candidates reported completing physical activity or screen-viewing courses during their post-secondary training, respectively. Candidates who completed one or more physical activity or screen-viewing courses exhibited significantly greater (p \u3c.05) self-efficacy than those without such training related to ensuring children were engaging in adequate moderate-to-vigorous physical activity (MVPA). Confidence to limit screen time did not differ. Candidates reporting meeting national physical activity recommendations (i.e., 150+ minutes of MVPA/week) exhibited significantly greater (p \u3c.05) physical activity-related self-efficacy than those not meeting these guidelines. Conclusions: Findings from this work highlight both the need for and the potential of supplementary physical activity and screen-viewing content in post-secondary ECE programs to benefit candidates\u27 knowledge and self-efficacy in these areas. Introducing this content at the post-secondary level will ensure that all early childhood educators are appropriately trained regarding physical activity and screen-viewing before entering a childcare-based profession, where they can positively influence young children\u27s health behaviours
Performance analysis of AlGaAs/GaAs tunnel junctions for ultra-high concentration photovoltaics
An n(++)-GaAs/p(++)-AlGaAs tunnel junction with a peak current density of 10 100Acm(-2) is developed. This device is a tunnel junction for multijunction solar cells, grown lattice-matched on standard GaAs or Ge substrates, with the highest peak current density ever reported. The voltage drop for a current density equivalent to the operation of the multijunction solar cell up to 10 000 suns is below 5 mV. Trap-assisted tunnelling is proposed to be behind this performance, which cannot be justified by simple band-to-band tunnelling. The metal-organic vapour-phase epitaxy growth conditions, which are in the limits of the transport-limited regime, and the heavy tellurium doping levels are the proposed origins of the defects enabling trap-assisted tunnelling. The hypothesis of trap-assisted tunnelling is supported by the observed annealing behaviour of the tunnel junctions, which cannot be explained in terms of dopant diffusion or passivation. For the integration of these tunnel junctions into a triple-junction solar cell, AlGaAs barrier layers are introduced to suppress the formation of parasitic junctions, but this is found to significantly degrade the performance of the tunnel junctions. However, the annealed tunnel junctions with barrier layers still exhibit a peak current density higher than 2500Acm(-2) and a voltage drop at 10 000 suns of around 20 mV, which are excellent properties for tunnel junctions and mean they can serve as low-loss interconnections in multijunction solar cells working at ultra-high concentrations
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A quantitative approach for measuring the reservoir of latent HIV-1 proviruses.
A stable latent reservoir for HIV-1 in resting CD4+ T cells is the principal barrier to a cure1-3. Curative strategies that target the reservoir are being tested4,5 and require accurate, scalable reservoir assays. The reservoir was defined with quantitative viral outgrowth assays for cells that release infectious virus after one round of T cell activation1. However, these quantitative outgrowth assays and newer assays for cells that produce viral RNA after activation6 may underestimate the reservoir size because one round of activation does not induce all proviruses7. Many studies rely on simple assays based on polymerase chain reaction to detect proviral DNA regardless of transcriptional status, but the clinical relevance of these assays is unclear, as the vast majority of proviruses are defective7-9. Here we describe a more accurate method of measuring the HIV-1 reservoir that separately quantifies intact and defective proviruses. We show that the dynamics of cells that carry intact and defective proviruses are different in vitro and in vivo. These findings have implications for targeting the intact proviruses that are a barrier to curing HIV infection
No effect of glutamine supplementation and hyperoxia on oxidative metabolism and performance during high-intensity exercise.
addresses: Health and Biology, Liverpool Hope University, Liverpool, UK. [email protected]: Comparative Study; Journal ArticleThis is an Author's Accepted Manuscript of an article published in Journal of Sports Sciences, 2008, Vol. 26, Issue 10, pp. 1081 â 1090 © 2008 copyright Taylor & Francis, available online at: http://www.tandfonline.com/doi/abs/10.1080/02640410801930200Glutamine enhances the exercise-induced expansion of the tricarboxylic acid intermediate pool. The aim of the present study was to determine whether oral glutamine, alone or in combination with hyperoxia, influenced oxidative metabolism and cycle time-trial performance. Eight participants consumed either placebo or 0.125 g kg body mass(-1) of glutamine in 5 ml kg body mass(-1) placebo 1 h before exercise in normoxic (control and glutamine respectively) or hyperoxic (FiO(2) = 50%; hyperoxia and hyperoxia + glutamine respectively) conditions. Participants then cycled for 6 min at 70% maximal oxygen uptake (VO(2max)) immediately before completing a brief high-intensity time-trial (approximately 4 min) during which a pre-determined volume of work was completed as fast as possible. The increment in pulmonary oxygen uptake during the performance test (DeltaVO(2max), P = 0.02) and exercise performance (control: 243 s, s(x) = 7; glutamine: 242 s, s(x) = 3; hyperoxia: 231 s, s(x) = 3; hyperoxia + glutamine: 228 s, s(x) = 5; P < 0.01) were significantly improved in hyperoxic conditions. There was some evidence that glutamine ingestion increased DeltaVO(2max) in normoxia, but not hyperoxia (interaction drink/FiO(2), P = 0.04), but there was no main effect or impact on performance. Overall, the data show no effect of glutamine ingestion either alone or in combination with hyperoxia, and thus no limiting effect of the tricarboxylic acid intermediate pool size, on oxidative metabolism and performance during maximal exercise
Implementation of an e-Learning course in physical activity and sedentary behavior for pre- and in-service early childhood educators: Evaluation of the TEACH pilot study
Background: Childcare-based physical activity (PA) and sedentary behavior (SB) interventions have traditionally used in-person training to supplement early childhood educatorsâ (ECEs) knowledge and confidence to facilitate physically active programming for the children in their care. However, this method of delivery is resource-intensive and unable to reach a high number of ECEs. The purpose of the Training pre-service EArly CHildhood educators in PA (TEACH) pilot study was to test the implementation (e.g., fidelity, feasibility, acceptability) of an e-Learning course targeting PA and SB among a sample of pre-service (i.e., post-secondary students) and in-service (i.e., practicing) ECEs in Canada. Methods: A pre-/post-study design was adopted for this pilot study, and implementation outcomes were assessed cross-sectionally at post-intervention. Pre-service ECEs were purposefully recruited from three Canadian colleges and in-service ECEs were recruited via social media. Upon completing the e-Learning course, process evaluation surveys (n = 32 pre-service and 121 in-service ECEs) and interviews (n = 3 pre-service and 8 in-service ECEs) were completed to gather ECEsâ perspectives on the e-Learning course. Fidelity was measured via e-Learning course metrics retrieved from the web platform. Descriptive statistics were calculated for quantitative data, and thematic analysis was conducted to analyze qualitative data. Results: Moderate-to-high fidelity to the TEACH study e-Learning course was exhibited by pre-service (68%) and in-service (63%) ECEs. Participants reported that the course was highly acceptable, compatible, effective, feasible, and appropriate in complexity; however, some ECEs experienced technical difficulties with the e-Learning platform and noted a longer than anticipated course duration. The most enjoyed content for pre- and in-service ECEs focused on outdoor play (87.5% and 91.7%, respectively) and risky play (84.4% and 88.4%, respectively). Conclusions: These findings demonstrate the value of e-Learning for professional development interventions for ECEs. Participant feedback will be used to make improvements to the TEACH e-Learning course to improve scalability of this training
Change in pre- and in-service early childhood educatorsâ knowledge, self-efficacy, and intentions following an e-learning course in physical activity and sedentary behaviour: a pilot study
Background: Early childhood educators (ECEs) are the primary daytime role models for many young children, and are responsible for facilitating physical activity (PA) opportunities and minimizing sedentary behaviour (SB) in childcare. However, they have reportedly received little related education in their pre-service training. The purpose of the Training pre-service EArly CHildhood educators in physical activity (TEACH) pilot study was to explore changes in pre- and in-service ECEsâ knowledge, self-efficacy, behavioural intention, and perceived behavioural control following the TEACH e-Learning course in PA and SB. Methods: Pre-service ECEs were purposefully recruited from three Canadian colleges, while in-service ECEs were recruited via social media. A pre-post study design was used. ECEs completed two online surveys; one prior to, and one immediately following the completion of the TEACH e-Learning course (~ 5 h). Descriptive statistics were reported, and McNemar Chi-Square tests and paired samples t-tests were used to examine changes in ECEsâ question-specific, and total knowledge scores, respectively. Wilcoxon Signed Ranks tests were employed to examine changes in self-efficacy, behavioural intention, and perceived behavioural control. Results: Both pre- (n = 32) and in-service (n = 121) ECEs significantly increased their total knowledge scores from pre- to post-course completion (p \u3c.05*). Significant positive changes in self-efficacy (p \u3c.025*), behavioural intention (p \u3c.007*), and perceived behavioural control (p \u3c.007*) were demonstrated by in-service ECEs following course completion, while only select composite scores within these tools were significant among pre-service ECEs. Conclusions: These findings provide preliminary evidence of the potential efficacy of the e-Learning course at improving ECEsâ knowledge, self-efficacy, behavioural intention, and perceived behavioural control to support PA and minimize SB in childcare. Following the success of the pilot study, testing the effectiveness of the TEACH e-Learning course on a larger scale, with a comparison group, is warranted prior to recommending broader dissemination of the training in pre-service ECE programs and for in-service ECE professional learning
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