2,911 research outputs found

    Maximal Voluntary Activation of the Elbow Flexors Is under Predicted by Transcranial Magnetic Stimulation Compared to Motor Point Stimulation Prior to and Following Muscle Fatigue

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    Transcranial magnetic (TMS) and motor point stimulation have been used to determine voluntary activation (VA). However, very few studies have directly compared the two stimulation techniques for assessing VA of the elbow flexors. The purpose of this study was to compare TMS and motor point stimulation for assessing VA in non-fatigued and fatigued elbow flexors. Participants performed a fatigue protocol that included twelve, 15 s isometric elbow flexor contractions. Participants completed a set of isometric elbow flexion contractions at 100, 75, 50, and 25% of maximum voluntary contraction (MVC) prior to and following fatigue contractions 3, 6, 9, and 12 and 5 and 10 min post-fatigue. Force and EMG of the bicep and triceps brachii were measured for each contraction. Force responses to TMS and motor point stimulation and EMG responses to TMS (motor evoked potentials, MEPs) and Erb's point stimulation (maximal M-waves, Mmax) were also recorded. VA was estimated using the equation: VA% = (1−SITforce/PTforce) × 100. The resting twitch was measured directly for motor point stimulation and estimated for both motor point stimulation and TMS by extrapolation of the linear regression between the superimposed twitch force and voluntary force. MVC force, potentiated twitch force and VA significantly (p < 0.05) decreased throughout the elbow flexor fatigue protocol and partially recovered 10 min post fatigue. VA was significantly (p < 0.05) underestimated when using TMS compared to motor point stimulation in non-fatigued and fatigued elbow flexors. Motor point stimulation compared to TMS superimposed twitch forces were significantly (p < 0.05) higher at 50% MVC but similar at 75 and 100% MVC. The linear relationship between TMS superimposed twitch force and voluntary force significantly (p < 0.05) decreased with fatigue. There was no change in triceps/biceps electromyography, biceps/triceps MEP amplitudes, or bicep MEP amplitudes throughout the fatigue protocol at 100% MVC. In conclusion, motor point stimulation as opposed to TMS led to a higher estimation of VA in non-fatigued and fatigued elbow flexors. The decreased linear relationship between TMS superimposed twitch force and voluntary force led to an underestimation of the estimated resting twitch force and thus, a reduced VA

    Nanotechnology in multimodal theranostic capsule endoscopy

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    Video capsule endoscopy (VCE) has become a clinically accepted diagnostic modality in the last 20 years and has established a technological roadmap for other capsule endoscopy (CE) devices, incorporating microscale technology, a local power supply and wireless communication. However, VCE does not provide a therapeutic function and research in therapeutic capsule endoscopy (TCE) has been limited. This paper proposes a new route towards viable TCE based on multiple CE devices including essential nanoscale components. A first device is used for multimodal diagnosis, with quantitative microultrasound as a complement to video imaging. Ultrasound-enhanced fluorescent marking of sites of pathology allows follow-up with a second device for therapy. This is based on fluorescence imaging and ultrasound-mediated targeted drug delivery. Subsequent treatment verification and monitoring with a third device exploits the minimally invasive nature of CE. Clinical implementation of a complete patient pathway remains the subject of research but several key components have been prepared in early prototype form. These are described, along with gaps that remain to be filled

    Models and metaphors: complexity theory and through-life management in the built environment

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    Complexity thinking may have both modelling and metaphorical applications in the through-life management of the built environment. These two distinct approaches are examined and compared. In the first instance, some of the sources of complexity in the design, construction and maintenance of the built environment are identified. The metaphorical use of complexity in management thinking and its application in the built environment are briefly examined. This is followed by an exploration of modelling techniques relevant to built environment concerns. Non-linear and complex mathematical techniques such as fuzzy logic, cellular automata and attractors, may be applicable to their analysis. Existing software tools are identified and examples of successful built environment applications of complexity modelling are given. Some issues that arise include the definition of phenomena in a mathematically usable way, the functionality of available software and the possibility of going beyond representational modelling. Further questions arising from the application of complexity thinking are discussed, including the possibilities for confusion that arise from the use of metaphor. The metaphor of a 'commentary machine' is suggested as a possible way forward and it is suggested that an appropriate linguistic analysis can in certain situations reduce perceived complexity

    Preparation of ceramic microlectromechanical systems (MEMS) using a gelcasting consolidation technique

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    The present work focuses the preparation and characterisation of suspensions withthree different powders, ferrite, PZT and alumina, for the fabrication of 3D-shapedceramic structures by gelcasting. The characterization of powders by particle size ispresented together with the preparation and characterization of the resultingsuspensions by rheological and zeta potential measurements. Using 1-wt% of DispexA-40 is possible to prepare concentrated PZT and ferrite suspensions to beconsolidated by gelcasting. The workability of gelcasting technique is demonstratedon a range of component geometries suitable for MEMS applications

    Changes in hedgerow floral diversity over 70 years in an English rural landscape, and the impacts of management

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    Hedgerows provide key habitat and refuges for wildlife in otherwise intensively-managed landscapes, and may play a role in connecting increasingly fragmented habitats. However, the processes governing changes to the floral biodiversity of hedges are poorly understood. We analysed a unique, long-term data set of plant species richness over a 70 year period at 357 hedgerow sites in southern England to quantify changes in a, b and c diversity, and identify the role of hedge management and other possible drivers of change. Alpha diversity increased in hedgerows, while a reduction in b diversity was indicated by taxonomic homogenisation, whereby previously distinct communities of species become more similar to one another over time. Changes in the regional species pool (c diversity) differed with plant life-history; it increased for woody species but decreased among herbaceous hedge species. Hedgerow communities shifted towards species associated with higher soil fertility, a more competitive ecological strategy and, in unmanaged hedgerows, greater shade tolerance. Probable drivers for these changes include the move from traditional forms of management such as coppicing and hedge-laying towards either no management or frequent cutting with a mechanical flail, and eutrophication. The extent of changes in plant diversity over time was determined by both historical and recent hedgerow management, but these management effects varied with plant life-history attributes. However, changes in hedge quality and floral diversity were not linked directly to a 60% increase in the proportion of land use categories classified as ‘intensive’ adjacent to the sites over the 70 years. Recommendations are made for future hedgerow management based on conservation objectives for specific groups of hedge plant species

    Erasmus Language students in a British University – a case study

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    Students’ assessment of their academic experience is actively sought by Higher Education institutions, as evidenced in the National Student Survey introduced in 2005. Erasmus students, despite their growing numbers, tend to be excluded from these satisfaction surveys, even though they, too, are primary customers of a University. This study aims to present results from bespoke questionnaires and semi-structured interviews with a sample of Erasmus students studying languages in a British University. These methods allow us insight into the experience of these students and their assessment as a primary customer, with a focus on language learning and teaching, university facilities and student support. It investigates to what extent these factors influence their levels of satisfaction and what costs of adaptation if any, they encounter. Although excellent levels of satisfaction were found, some costs affect their experience. They relate to difficulties in adapting to a learning methodology based on a low number of hours and independent learning and to a guidance and support system seen as too stifling. The results portray this cohort’s British University as a well-equipped and well-meaning but ultimately overbearing institution, which may indicate that minimising costs can eliminate some sources of dissatisfaction

    Measurement of the Branching Fraction for B- --> D0 K*-

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    We present a measurement of the branching fraction for the decay B- --> D0 K*- using a sample of approximately 86 million BBbar pairs collected by the BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the K*- through its decay to K0S pi-. We measure the branching fraction to be B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid Communications

    Measurement of the Proton and Deuteron Spin Structure Function g_1 in the Resonance Region

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    We have measured the proton and deuteron spin structure functions g_1^p and g_1^d in the region of the nucleon resonances for W^2 < 5 GeV^2 and Q20.5Q^2\simeq 0.5 and Q21.2Q^2\simeq 1.2 GeV^2 by inelastically scattering 9.7 GeV polarized electrons off polarized 15NH3^{15}NH_3 and 15ND3^{15}ND_3 targets. We observe significant structure in g_1^p in the resonance region. We have used the present results, together with the deep-inelastic data at higher W^2, to extract Γ(Q2)01g1(x,Q2)dx\Gamma(Q^2)\equiv\int_0^1 g_1(x,Q^2) dx. This is the first information on the low-Q^2 evolution of Gamma toward the Gerasimov-Drell-Hearn limit at Q^2 = 0.Comment: 7 pages, 2 figure

    Specialist role coaching and skill training periodisation: A football goalkeeping case study

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    © The Author(s) 2020. In sports like association football, professional teams are increasingly devoting resources to the role-based development of individual athletes and sub-groups. By employing ‘specialist coaches’ into athlete-support structures, clubs aim to facilitate individualised athlete training programs to enhance performance preparation as well as skill learning and talent development. Here, we discuss how contemporary pedagogical training approaches, like Nonlinear Pedagogy and the Constraints-Led approach, can enhance effectiveness of specialist role-based athlete development programs to facilitate performance functionality. We argue the need for a model of specialist role-based coaching practice in high performance sports organisations, based on a unified theoretical rationale, such as ecological dynamics. To exemplify the nature of specialist role-based coaching, a case study addresses how Nonlinear Pedagogy and Constraints-Led approach are being used for training professional football goalkeepers in an U23 years age group. Integrating key concepts from ecological dynamics, allied to principles of Nonlinear Pedagogy and the Constraints-Led approach, common skill training principles for specialist role coaches are highlighted. These illustrate the use of the recently introduced ‘Periodization of Skill Training’ framework for specialist role coaching, practically exemplifying a way to harness opportunities for performance enhancement and individualised talent development in the football goalkeeping context
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