Using accelerometry to quantify deceleration during a high-intensity soccer turning manoeuvre     

Niels Jensby Nedergaard  Uwe Kersting 《Journal of sports sciences》2014,32(20):1897-1905

Abstract

The mechanics of cutting movements have been investigated extensively, but few studies have considered the rapid deceleration phase prior to turning which has been linked to muscle damage. This study used accelerometry to examine the influence of turning intensity on the last three steps of a severe turn.

Ten soccer players performed 135° “V” cuts at five different intensities. Resultant decelerations were recorded from a trunk-mounted tri-axial accelerometer. Lower limb kinematics and ground reaction forces (GRF) from the pivot foot-ground contact (FGC) were also monitored.

Average peak trunk decelerations were larger at the two preceding steps (4.37 ± 0.12 g and 4.58 ± 0.11 g) compared to the PIVOT step (4.10 ± 0.09 g). Larger peak joint flexion angular velocities were observed at PRE step (ankle: 367 ± 192 deg.s^?1; knee 493 ± 252 deg.s^?1) compared to PIVOT step (ankle 255 ± 183 deg.s^?1; knee 377 ± 229 deg.s^?1). Turn intensity did not influence peak GRF at PIVOT step.

This study highlights the importance of steps prior to turning and their high-frequency loading characteristics. It is suggested that investigations of lower limb loading during turning should include this deceleration phase and not focus solely on pivot FGC.  相似文献   

The Role of Motor Competences in Predicting Working Memory Maintenance and Preparatory Processing     

Sebastian Ludyga  Manuel Mücke  Keita Kamijo  Christian Andrä  Uwe Pühse  Markus Gerber  Christian Herrmann 《Child development》2020,91(3):799-813

The purpose of the study was the examination of the longitudinal association between motor competences and changes in preparatory processing during a task requiring working memory maintenance. At baseline, 52 Caucasian children aged 10–12 years completed the MOBAK-5 test battery and a Sternberg task, whereas the cue-P300 and the initial contingent negative variation (iCNV) were recorded via electroencephalography. After 9 months, the Sternberg task was administered again to assess changes in these neurophysiological indices and behavioral performance. Path analyses revealed that motor competences predicted the change in cue-P300 and iCNV from baseline to follow-up. The present findings indicate that the cognitive control strategy during a task demanding working memory maintenance changes as a function of children's baseline motor competences.  相似文献   

Moderate-to-vigorous physical activity,executive functions and prefrontal brain oxygenation in children: A functional near-infrared spectroscopy study     

Manuel Mücke  Christian Andrä  Markus Gerber  Uwe Pühse 《Journal of sports sciences》2018,36(6):630-636

Despite accumulating evidence that regular exercise improves executive functioning, the underlying neurophysiological mechanisms have rarely been investigated. The present study aimed to compare cognitive performance as well as task-specific concentration changes in oxygenated haemoglobin in the prefrontal cortex between children with higher and lower moderate-to-vigorous physical activity (MVPA). Physical activity was measured over 7 consecutive days using actigraphy. Afterwards, participants (N = 50) completed verbal fluency tests (VFTs) and mental arithmetic (MA) for the assessment of cognitive flexibility and working memory capacity. During the tasks, changes of oxygenated haemoglobin were measured with functional near-infrared spectroscopy. Using average MVPA of 11-year-old children as cut-point, the sample was divided into children with lower and higher MVPA. Analyses of variance revealed no significant differences in correct and false responses on the cognitive tests between groups. With regard to oxygenated haemoglobin, no group differences were found for concentration changes in response to the cognitive tasks. In conclusion, VFTs and MA increased children’s activation in prefrontal regions associated with cognitive flexibility and working memory, respectively. However, these executive functions and cortical activation were not different between children with lower and higher MVPA.  相似文献   

Science in the Third Reich: Margit Szöllösi-Janze (ed.), <Emphasis Type="Italic">Science in the Third Reich (German Historical Perspectives,XII</Emphasis>) (Oxford/New York: Berg, 2001), 289 pp., ISBN: 1-85973-421-9     

Wolfgang?Uwe?EckartEmail author 《Minerva》2004,42(4):451-454

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Response to "Who spares the rod? religous orientation, social conformity, and child abuse potential" [Rodriguez, Henderson, Child Abuse & Neglect 34 (2) (2010) 84-94     

Breiner SJ 《Child abuse & neglect》2011,35(4):235

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Can young students understand the mathematical concept of equality? A whole-year arithmetic teaching experiment in second grade     

Fischer  Jean-Paul  Sander  Emmanuel  Sensevy  Gérard  Vilette  Bruno  Richard  Jean-François 《European Journal of Psychology of Education - EJPE》2019,34(2):439-456

European Journal of Psychology of Education - Ensuring students correctly understand the notion of equality is a fundamental problem in teaching mathematics. Is it possible to teach arithmetic in...  相似文献   

Down the Rabbit Hole: Using The Matrix to Reflect on Teacher Education     

Katherine Batchelor  Scott A. Sander 《Studying Teacher Education》2017,13(1):68-86

In this article we use The Matrix movie as a heuristic device that offers two possibilities for conceptualizing teacher education: as a mirror (looking at ourselves) and as a window (looking at teacher education). We begin by sharing our interests and reason for using self-study while examining the components of The Matrix, noting parallels between key elements in our educational world and Neo’s world. Here we unpack scenes from the movie while making connections between the Matrix world and the world of education in order to problematize many of the longstanding, traditional notions that hinder or prevent all of us from awakening fully. We then discuss how our journeys have been influenced and altered by both self-study and curriculum study, noting the many similarities of our plight of existence with Neo’s false reality by using our experiences as a lens to re-surface the messages in The Matrix for a new generation. These messages can serve as entry points in order to initiate conversations that expand current notions of the role of a teacher and the purpose of school toward more socially-just, democratic ends. We close with personal revelations and implications and consider how our stories can be used as a point-of-entry that can inform teacher preparation. Overall, we hope that our experiences will help others begin to question the seemingly common-sense notions and often unquestioned traditions deeply entrenched in our current world of education that are related to teaching, learning, and learning to teach.  相似文献   

DNA-library assembly programmed by on-demand nano-liter droplets from a custom microfluidic chip     

Uwe Tangen  Gabriel Antonio S. Minero  Abhishek Sharma  Patrick F. Wagler  Rafael Cohen  Ofir Raz  Tzipy Marx  Tuval Ben-Yehezkel  John S. McCaskill 《Biomicrofluidics》2015,9(4)

Nanoscale synthetic biology can benefit from programmable nanoliter-scale processing of DNA in microfluidic chips if they are interfaced effectively to biochemical arrays such as microwell plates. Whereas active microvalve chips require complex fabrication and operation, we show here how a passive and readily fabricated microchip can be employed for customizable nanoliter scale pipetting and reaction control involving DNA. This recently developed passive microfluidic device, supporting nanoliter scale combinatorial droplet generation and mixing, is here used to generate a DNA test library with one member per droplet exported to addressed locations on microwell plates. Standard DNA assembly techniques, such as Gibson assembly, compatible with isothermal on-chip operation, are employed and checked using off-chip PCR and assembly PCR. The control of output droplet sequences and mixing performance was verified using dyes and fluorescently labeled DNA solutions, both on-chip and in external capillary channels. Gel electrophoresis of products and DNA sequencing were employed to further verify controlled combination and functional enzymatic assembly. The scalability of the results to larger DNA libraries is also addressed by combinatorial input expansion using sequential injection plugs from a multiwell plate. Hence, the paper establishes a proof of principle of the production of functional combinatorial mixtures at the nanoliter scale for one sequence per well DNA libraries.  相似文献   

On demand nanoliter-scale microfluidic droplet generation,injection, and mixing using a passive microfluidic device     

Uwe Tangen  Abhishek Sharma  Patrick Wagler  John S. McCaskill 《Biomicrofluidics》2015,9(1)

We here present and characterize a programmable nanoliter scale droplet-on-demand device that can be used separately or readily integrated into low cost single layer rapid prototyping microfluidic systems for a wide range of user applications. The passive microfluidic device allows external (off-the-shelf) electronically controlled pinch valves to program the delivery of nanoliter scale aqueous droplets from up to 9 different inputs to a central outlet channel. The inputs can be either continuous aqueous fluid streams or microliter scale aqueous plugs embedded in a carrier fluid, in which case the number of effective input solutions that can be employed in an experiment is no longer strongly constrained (100 s–1000 s). Both nanoliter droplet sequencing output and nanoliter-scale droplet mixing are reported with this device. Optimization of the geometry and pressure relationships in the device was achieved in several hardware iterations with the support of open source microfluidic simulation software and equivalent circuit models. The requisite modular control of pressure relationships within the device is accomplished using hydrodynamic barriers and matched resistance channels with three different channel heights, custom parallel reversible microfluidic I/O connections, low dead-volume pinch valves, and a simply adjustable array of external screw valves. Programmable sequences of droplet mixes or chains of droplets can be achieved with the device at low Hz frequencies, limited by device elasticity, and could be further enhanced by valve integration. The chip has already found use in the characterization of droplet bunching during export and the synthesis of a DNA library.  相似文献   

Impacts of government incentives towards industrial innovation: An analysis of the federal programme funding R&D personnel in the Federal Republic of Germany     

Frieder Meyer-Krahmer  Gisela Gilelow  Uwe Kuntze 《Research Policy》1983,12(3):153-169

Against a background of deteriorating national and international economic conditions, increasing importance is being attached by political administrations to the innovative capacities of small and medium-sized firms with respect to the employment situation and to international competitiveness. Consequently, government support of research, development and innovation in these companies has taken a marked upward turn since the late seventies, both in the Federal Republic of Germany and in other industrialized Western countries.The actual impacts of some of these programmes are at present under study by the Fraunhofer-Institut für Systemtechnik und Innovationsforschung (ISI). This paper is an outline of the results of a study of the largest current programme funding R&D and innovation in small and medium-sized firms by offering grants towards the costs of R&D personnel. The impact analysis is being conducted in two rounds: the first round of studies, which is the subject of this report, took place in 1980/1981 and was designed to examine the discernible short-term effects and characteristics of the programme. The second round is planned for 1983/1984 as a summary of the impacts of the programme over the first five years of its term of effect.The subjects of investigation are the quantitative and qualitative changes in R&D activities caused by the programme in the firms under study and the contribution the programme can make to strengthen innovative and competitive capabilities. The conditions underlying the programme are reviewed critically, especially in order to see whether the barriers to innovation and the weak spots assumed did in fact exist in the firms examined. The administrative management, “free rider”-effects, and factors restricting impacts are investigated along with such questions as whether firms located in peripheral regions were reached by the programme to the same extent as firms in conurbation areas. Furthermore, the reasons for non-participation of firms are analyzed.The example of the federal programme funding R&D personnel thus is used in this impact analysis in an attempt to provide empirical data on the significance, the range, and the limits of such a government instrument promoting R&D and innovation in small and medium-sized firms.  相似文献