4,984 research outputs found

    Quiet Eye Training in a Visuomotor Control Task

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    Introduction: Several researchers have reported the importance of maintaining a longer final fixation on the target (termed the quiet eye period, QE) prior to performing an aiming task. We present an innovative, perceptual training intervention intended to improve the efficiency of gaze behavior (i.e., QE) in shotgun shooting. Methods: A sample of 20 International-level, skeet shooters were assigned equally to one of two, matched-ability groups based on their pre-test shooting scores. A perceptual training group participated in a 4-step, pre-shot routine, alongside three video feedback sessions involving their own gaze behaviors and those of an expert model in an effort to influence positively QE behaviors. A control group received video feedback of performance, but without the addition of feedback on QE behaviors. Participants completed pre- and post-tests along with an 8-week training intervention. Results: The perceptual training group significantly increased its mean QE duration (397 cw 423 ms), employed an earlier onset of QE (257 cw 244 ms), and recorded higher shooting accuracy scores (62 cw 70 %) from pre- to post-test. Participants in the perceptual training group significantly reduced gun barrel displacement and absolute peak velocity on the post- compared to the pre-test, even though neither variable was overtly trained. A transfer test, based on performance during competition, indicated that perceptual training significantly improved shooting accuracy pre- to post-intervention. No pre- to post-test differences were observed for the control group on the measures reported. Conclusion: The results demonstrate the effectiveness of QE training in improving shooting accuracy and developing a more efficient visuo-motor control strategy. Findings have implications for future research on training visuo-motor behaviors, attention and gaze orientation during the performance of aiming tasks

    Platelet-derived transforming growth factor-β1 promotes keratinocyte proliferation in cutaneous wound healing.

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    Platelets are a recognised potent source of transforming growth factor-β1 (TGFβ1), a cytokine known to promote wound healing and regeneration by stimulating dermal fibroblast proliferation and extracellular matrix deposition. Platelet lysate has been advocated as a novel personalised therapeutic to treat persistent wounds, although the precise platelet-derived growth factors responsible for these beneficial effects have not been fully elucidated. The aim of this study was to investigate the specific role of platelet-derived TGFβ1 in cutaneous wound healing. Using a transgenic mouse with a targeted deletion of TGFβ1 in megakaryocytes and platelets (TGFβ1fl/fl .PF4-Cre), we show for the first time that platelet-derived TGFβ1 contributes to epidermal and dermal thickening and cellular turnover after excisional skin wounding. In vitro studies demonstrate that human dermal fibroblasts stimulated with platelet lysate containing high levels of platelet-derived TGFβ1 did not exhibit enhanced collagen deposition or proliferation, suggesting that platelet-derived TGFβ1 is not a key promoter of these wound healing processes. Interestingly, human keratinocytes displayed enhanced TGFβ1-driven proliferation in response to platelet lysate, reminiscent of our in vivo findings. In summary, our novel findings define and emphasise an important role of platelet-derived TGFβ1 in epidermal remodelling and regeneration processes during cutaneous wound healing

    Anxiety, Movement Kinematics, and Visual Attention in Elite-Level Performers

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    We tested the predictions of Attentional Control Theory (ACT) by examining the effect of anxiety on attention control and the subsequent influence on both performance effectiveness and performance efficiency within a perceptual-motor context. A sample (N = 16) of elite shotgun shooters was tested under counterbalanced low (practice) and high (competition) anxiety conditions. A head-mounted, corneal reflection system allowed point of gaze to be calculated in relation to the scene, while motion of the gun was evaluated using markers placed on the barrel which were captured by two stationary cameras and analyzed using optical tracking software. The quiet eye (QE) duration and onset were analyzed along with gun barrel displacement and variability; performance outcome scores (successful vs. unsuccessful) were also recorded. QE (Vickers, 1996) is defined as the final fixation or tracking gaze that is located on a specific location/object in the visual display for a minimum of 100 ms. Longer QE durations have been linked to successful performance in previous research involving aiming tasks. Participants demonstrated shorter quiet eye durations, and less efficient gun motion, along with a decreased performance outcome (fewer successful trials) under high compared with low anxiety conditions. The data support the predictions of ACT with anxiety disrupting control processes such that goal-directed attention was compromised, leading to a significant impairment in performance effectiveness

    Regulation of connective tissue growth factor/CCN2 gene expression in systematic sclerosis fibroblasts

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    Systemic sclerosis (Scleroderma, SSc) is a chronic, connective tissue disease of unknown etiology, characterised by vascular dysfunction, iriflarnmation and organ fibrosis. Involving both genetic and environmental components, the specific mechanisms which result in fibrosis remain largely unknown. A cardinal feature of SSc is increased synthesis of extracellular matrix (ECM). Dermal fibroblasts cultured from SSc patients maintain many of the abnormal properties seen in vivo, including excess production of collagen type I, and growth factors such as connective tissue growth factor (CTGF/CCN2). CTGF, like many genes dysregulated in SSc, is induced by TGF- p in normal fibroblasts. The overall aim of my studies was to determine the mechanism(s) controlling CTGF over-expression in SSc dermal fibroblasts (SDF). Induction of CTGF by TGF-p was found to be dependent upon elements in the proximal portion of the CTGF promoter, distinct from those of the previously characterised TGF- P response element (TRE). The TRE acts, in NIH/3T3 and HFF cells, as a regulator of basal expression, and is not essential for TGF-P induction of CTGF. Instead TGF-p induces CTGF expression via a Smad3 complex, binding to a bona fide SMAD transcription factor binding site. Over-expression CTGF in SDF is independent of autocrine expression of TGF-P and the SMAD binding element and rather dependent on a functional Sp-binding site. Inhibition of Spl-like DNA binding reduces excessive CTGF expression in SDF. Consistent with this Spl-DNA binding activity is elevated in SDF nuclear extracts. Investigation of the mechanism of elevated Spl-like binding found that SDF exhibited constitunVely active ERK1/2 and JNK1. Inhibition of ERK1/2 repressed elevated Sp-binding and CTGF over-expression observed in SDF. In summary, the data presented in this thesis provide evidence that dysregulation of ERK1/2 in SDF is involved in CTGF over-expression via a Spl-like DNA binding. Thus repression of ERK may represent a candidate in targeting fibrosis in SSc

    Modelling e-learner comprehension within a conversational intelligent tutoring system

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    Conversational Intelligent Tutoring Systems (CITS) are agent based e-learning systems which deliver tutorial content through discussion, asking and answering questions, identifying gaps in knowledge and providing feedback in natural language. Personalisation and adaptation for CITS are current research focuses in the field. Classroom studies have shown that experienced human tutors automatically, through experience, estimate a learner’s level of subject comprehension during interactions and modify lesson content, activities and pedagogy in response. This paper introduces Hendrix 2.0, a novel CITS capable of classifying e-learner comprehension in real-time from webcam images. Hendrix 2.0 integrates a novel image processing and machine learning algorithm, COMPASS, that rapidly detects a broad range of non-verbal behaviours, producing a time-series of comprehension estimates on a scale from -1.0 to +1.0. This paper reports an empirical study of comprehension classification accuracy, during which 51 students at Manchester Metropolitan University undertook conversational tutoring with Hendrix 2.0. The authors evaluate the accuracy of strong comprehension and strong non-comprehension classifications, during conversational questioning. The results show that the COMPASS comprehension classifier achieved normalised classification accuracy of 75%

    Antimicrobial efficacy and mechanism of action of poly(amidoamine) (PAMAM) dendrimers against opportunistic pathogens.

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    The aim of this study was to investigate a range of poly(amidoamine) (PAMAM) dendrimer generations against Gram-positive and Gram-negative skin pathogens and to determine any differences in antimicrobial potency for different generations, characterising how differences in physicochemical properties influence antimicrobial efficacy. A range of tests were carried out, including viable count assays to determine IC50 values for each dendrimer, membrane integrity studies and an inner membrane permeabilisation assay. This is supported by scanning electron microscopy imaging of the interactions observed between dendrimers and bacteria. The results of this study indicate that the antimicrobial efficacy of native PAMAM dendrimers is dependent on generation, concentration and terminal functionalities, for example the MIC50 (Ï…g/mL) against S. aureus was between 26.77 for the G2-PAMAM-NH2 dendrimer and 2.881 for the G5-PAMAM-NH2 dendrimer. There was a strong correlation between membrane disruption and the determined biocidal activity, making it a key contributing mechanism of action. This study demonstrates that selection of the type of PAMAM dendrimer is important as their inherent antimicrobial efficacy varies according to their individual physicochemical properties. This understanding may pave the way for the development of enhanced dendrimer-based antimicrobial formulations and drug delivery systems

    Catalogue of Wave Energy Test Centres

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    The objective of this catalogue is to provide an overview of the development of wave energy projects across Europe. This is framed within the context of the need to address climate change and concerns over security of oil and gas supplies. Both of these have driven European policy-makers to develop and implement a European energy policy. The European Commission has set ambitious targets for all Member States through a Directive promoting the use of energy from renewable sources (2009/28/EC), taken forward at Member State level through a National Renewable Energy Action Plan (NREAP). Many coastal European States have recognised that marine renewable energy developments will play a key role in meeting their targets. This document presents the targets set by each State in their NREAP and specifically identifies the level of ocean energy (tidal or wave) that would be required to meet those targets. Offshore wind is included for comparative purposes. The NREAP targets are supplemented by ocean energy objectives garnered from various other strategies and roadmaps. This report also addressed the future potential spatial footprint of wave energy developments. The targets set in the NREAPs and other documented scenarios are used to calculate the potential number and spatial extent of wave energy farms required, based on the current state of the technology and operational experience. These predictions will provide an essential contribution to future Maritime Spatial Planning (MSP) systems in EU Member States. The final data section gives an overview of the wave energy development situation in Europe as of early 2011, summarising the wave energy projects that have been tested in the sea to date, those that are currently operational and those that are in the planning stage. These projects range from demonstration type projects to examples of where full-scale devices have been deployed or are planned for deployment in the near future. Information presented relates primarily to the physical characteristics of the site and the technology type in place. The catalogue concludes with a summary of the main findings from the above work. The document is accompanied by an Annex, with information on devices that have been tested in the sea since 1999, those that are currently operational and those that are in the planning stage. The data contained in the catalogue will act as the foundation for many of the SOWFIA Project‟s deliverables. Most imminently, an inventory of all available environmental impact data collected, or in the process of collection, at each of the wave energy test centres listed here will be developed. This catalogue therefore provides a snapshot of the state of the wave energy industry in Europe and its predicted development in the coming decade. It forms a baseline for understanding the developments needed in technology, policy, funding and monitoring. This is essential if the required European-wide device development and testing programmes, technical support infrastructure, and streamlined consenting and permitting regimes are to be developed to facilitate the growth of this industry. Throughout these processes, social, environmental and economic impacts must be considered. The report has four aims: to document the various targets set by coastal Member States for ocean energy; to determine the spatial requirements for these; to provide a methodology for progressing the technology; and to outline the devices that have been tested in the sea since 1999 and those that are in the planning stage.Inteligent Energy Europe Programme of the European Unio

    Assessing the Quality of Decision Support Technologies Using the International Patient Decision Aid Standards instrument (IPDASi)

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    Objectives To describe the development, validation and inter-rater reliability of an instrument to measure the quality of patient decision support technologies (decision aids). Design Scale development study, involving construct, item and scale development, validation and reliability testing. Setting There has been increasing use of decision support technologies – adjuncts to the discussions clinicians have with patients about difficult decisions. A global interest in developing these interventions exists among both for-profit and not-for-profit organisations. It is therefore essential to have internationally accepted standards to assess the quality of their development, process, content, potential bias and method of field testing and evaluation. Methods Scale development study, involving construct, item and scale development, validation and reliability testing. Participants Twenty-five researcher-members of the International Patient Decision Aid Standards Collaboration worked together to develop the instrument (IPDASi). In the fourth Stage (reliability study), eight raters assessed thirty randomly selected decision support technologies. Results IPDASi measures quality in 10 dimensions, using 47 items, and provides an overall quality score (scaled from 0 to 100) for each intervention. Overall IPDASi scores ranged from 33 to 82 across the decision support technologies sampled (n = 30), enabling discrimination. The inter-rater intraclass correlation for the overall quality score was 0.80. Correlations of dimension scores with the overall score were all positive (0.31 to 0.68). Cronbach's alpha values for the 8 raters ranged from 0.72 to 0.93. Cronbach's alphas based on the dimension means ranged from 0.50 to 0.81, indicating that the dimensions, although well correlated, measure different aspects of decision support technology quality. A short version (19 items) was also developed that had very similar mean scores to IPDASi and high correlation between short score and overall score 0.87 (CI 0.79 to 0.92). Conclusions This work demonstrates that IPDASi has the ability to assess the quality of decision support technologies. The existing IPDASi provides an assessment of the quality of a DST's components and will be used as a tool to provide formative advice to DSTs developers and summative assessments for those who want to compare their tools against an existing benchmark

    Accurate reconstruction of insertion-deletion histories by statistical phylogenetics

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    The Multiple Sequence Alignment (MSA) is a computational abstraction that represents a partial summary either of indel history, or of structural similarity. Taking the former view (indel history), it is possible to use formal automata theory to generalize the phylogenetic likelihood framework for finite substitution models (Dayhoff's probability matrices and Felsenstein's pruning algorithm) to arbitrary-length sequences. In this paper, we report results of a simulation-based benchmark of several methods for reconstruction of indel history. The methods tested include a relatively new algorithm for statistical marginalization of MSAs that sums over a stochastically-sampled ensemble of the most probable evolutionary histories. For mammalian evolutionary parameters on several different trees, the single most likely history sampled by our algorithm appears less biased than histories reconstructed by other MSA methods. The algorithm can also be used for alignment-free inference, where the MSA is explicitly summed out of the analysis. As an illustration of our method, we discuss reconstruction of the evolutionary histories of human protein-coding genes.Comment: 28 pages, 15 figures. arXiv admin note: text overlap with arXiv:1103.434
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