The dynamic control ratio at the equilibrium point (DCRe): introducing relative and absolute reliability scores     

Tobias Alt  Axel J. Knicker  Heiko K. Strüder 《Journal of sports sciences》2017,35(7):688-693

Analytical methods to assess thigh muscle balance need to provide reliable data to allow meaningful interpretation. However, reproducibility of the dynamic control ratio at the equilibrium point has not been evaluated yet. Therefore, the aim of this study was to compare relative and absolute reliability indices of its angle and moment values with conventional and functional hamstring–quadriceps ratios. Furthermore, effects of familiarisation and angular velocity on reproducibility were analysed. A number of 33 male volunteers participated in 3 identical test sessions. Peak moments (PMs) were determined unilaterally during maximum concentric and eccentric knee flexion (prone) and extension (supine position) at 0.53, 1.57 and 2.62 rad · s^–1. A repeated measure, ANOVA, confirmed systematic bias. Intra-class correlation coefficients and standard errors of measurement indicated relative and absolute reliability. Correlation coefficients were averaged over respective factors and tested for significant differences. All balance scores showed comparable low-to-moderate relative (<0.8–0.9) and good absolute reliability (<10%). Relative reproducibility of dynamic control equilibrium parameters augmented with increasing angular velocity, but not with familiarisation. At 2.62 rad · s^–1, high (moment: 0.906) to moderate (angle: 0.833) relative reliability scores with accordingly high absolute indices (4.9% and 6.4%) became apparent. Thus, the dynamic control equilibrium is an equivalent method for the reliable assessment of thigh muscle balance.  相似文献   

Polyelectrolyte multilayer surface functionalization of poly(dimethylsiloxane) (PDMS) for reduction of yeast cell adhesion in microfluidic devices     

Schmolke H  Demming S  Edlich A  Magdanz V  Büttgenbach S  Franco-Lara E  Krull R  Klages CP 《Biomicrofluidics》2010,4(4):44113

Polyelectrolyte multilayers (PEMs) based on the combinations poly(diallyldimethylammonium chloride)∕poly(acrylic acid) (PDADMAC∕PAA) and poly(allylamine hydrochloride)∕PAA (PAH∕PAA) were adsorbed on poly(dimethylsiloxane) (PDMS) and tested for nonspecific surface attachment of hydrophobic yeast cells using a parallel plate flow chamber. A custom-made graft copolymer containing poly(ethylene glycol) (PEG) side chains (PAA-g-PEG) was additionally adsorbed on the PEMs as a terminal layer. A suitable PEM modification effectively decreased the adhesion strength of Saccharomyces cerevisiae DSM 2155 to the channel walls. However, a further decrease in initial cell attachment and adhesion strength was observed after adsorption of PAA-g-PEG copolymer onto PEMs from aqueous solution. The results demonstrate that a facile layer-by-layer surface functionalization from aqueous solutions can be successfully applied to reduce cell adhesion strength of S. cerevisiae by at least two orders of magnitude compared to bare PDMS. Therefore, this method is potentially suitable to promote planktonic growth inside capped PDMS-based microfluidic devices if the PEM deposition is completed by a dynamic flow-through process.  相似文献   

Kinematic differences of elite and high-performance tennis players in the cross court and down the line forehand   总被引：1，自引：0，他引：1  

Landlinger J  Lindinger SJ  Stöggl T  Wagner H  Müller E 《Sports biomechanics / International Society of Biomechanics in Sports》2010,9(4):280-295

This study identified and compared the full body kinematics of different skill levels in the forehand groundstroke when balls were hit cross court and down the line. Forty-three three-dimensional retroreflective marker trajectories of six elite and seven high-performance players were recorded using an eight-camera 400 Hz, Vicon motion analysis system. The six highest horizontal velocity forehands with reliable kinematics of all participants were analysed for each specific situation (a total of 156 analysed shots). Significant differences (p < 0.01) and large effect sizes were observed between elite and high-performance players in linear velocity of the shoulder (2.0 vs. 1.2 m/s), angular velocity of the pelvis (295 vs. 168 degrees/s), and angular velocity of the upper trunk (453 vs. 292 degrees/s) at impact. The elite group showed a tendency towards higher racquet velocities at impact (p < 0.05). No significant differences were found in angular displacement of the racquet, hip alignment, or shoulder alignment at the completion of the backswing; nor did angular displacement vary significantly at impact. Irrespective of the group, different shoulder, hip, and racquet angles were found at impact, depending on the situation. The results should assist coaches when striving to improve their players' forehand.  相似文献   

Sporthistorisches aus den USA     

Sandra Heck  Bettina Kratzmüller 《Sportwissenschaft》2010,40(3):219-221

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Arms control for armed uninhabited vehicles: an ethical issue     

Jürgen Altmann 《Ethics and Information Technology》2013,15(2):137-152

Arming uninhabited vehicles (UVs) is an increasing trend. Widespread deployment can bring dangers for arms-control agreements and international humanitarian law (IHL). Armed UVs can destabilise the situation between potential opponents. Smaller systems can be used for terrorism. Using a systematic definition existing international regulation of armed UVs in the fields of arms control, export control and transparency measures is reviewed; these partly include armed UVs, but leave large gaps. For preventive arms control a general prohibition of armed UVs would be best. If that is unattainable, several measures should be taken. An explicit prohibition of autonomous attack, that is without a human decision, should be added to IHL. Concerning armed UVs remotely controlled by a human soldier, recommendations differ according to type or mission. New kinds of uninhabited nuclear-weapon carriers should be banned. Space weapons should be prohibited in general. UVs smaller than 0.2–0.5 m should be banned. Bigger remotely controlled armed UVs not equipped with weapons of mass destruction should be subject to numerical limitations in various categories. For these the Treaty on Conventional Armed Forces in Europe is an important precedent.  相似文献   

Schüleraktivitäten beim selbstorganisierten Lernen und deren Auswirkungen auf den Lernerfolg     

Jürgen?SeifriedEmail author 《Zeitschrift für Erziehungswissenschaft》2004,7(4):569-584

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What’s in a name? A problem of terminology     

A. A. Lumsdaine  David J. Klaus 《Educational technology research and development : ETR & D》1961,9(4):208-211

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Understanding Sport Organizations     

Trevor Slack  Günther Lüschen 《Sportwissenschaft》1998,28(1):98-99

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Sportökonomik: mehr Effizienz und Beratung für den Sport     

Martin-Peter Büch 《Sportwissenschaft》1998,28(3-4):431-434

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Entwicklung gro?er Systeme mit generischen Methoden – Eine übersicht über den Sonderforschungsbereich 501     

J. Avenhaus  R. Gotzhein  T. H?rder  L. Litz  K. Madlener  J. Nehmer  M. Richter  N. Ritter  D. Rombach  B. Schürmann und G. Zimmermann 《Informatik - Forschung und Entwicklung》1998,13(4):227-234

Ohne Zusammenfassung  相似文献