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Although patellar taping has been shown to reduce pain in participants with patellofemoral pain syndrome, the mechanisms of pain reduction have not completely been established following its application. The purpose of this study was to evaluate EMG activity of vastus medialis and vastus lateralis following the application of patellar taping during a functional single leg squat. Both vastus medialis obliquus-vastus lateralis onset and vastus medialis obliquus/vastus lateralis amplitude of 18 participants with patellofemoral pain syndrome and 18 healthy participants as controls were measured using an EMG unit. This procedure was performed on the affected knee of participants with patellofemoral pain syndrome, before, during, and after patellar taping during unilateral squatting. The same procedure was also performed on the unaffected knees of both groups. The mean values of vastus medialis obliquus-vastus lateralis onset prior to taping (2.54 ms, s = 4.35) were decreased significantly following an immediate application of tape (-3.22 ms, s = 3.45) and after a prolonged period of taping (-6.00 ms, s = 3.40 s) (P < 0.05). There was also a significant difference between the mean values of vastus medialis obliquus-vastus lateralis onset among controls (-2.03 ms, s = 6.04) and participants with patellofemoral pain syndrome prior to taping (P < 0.05). However, there were no significant difference between the ranked values of vastus medialis obliquus/vastus lateralis amplitude of the affected and unaffected knees of participants with patellofemoral pain syndrome and controls during different conditions of taping (P > 0.05). Decreased values of vastus medialis obliquus-vastus lateralis onset may contribute to patellar realignment and explain the mechanism of pain reduction following patellar taping in participants with patellofemoral pain syndrome. 相似文献
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The questions focus on the emergence of education for sustainable development in the French university. The case study discusses the curricular examination of the Bachelor of Territory Professional Planning in 17 universities and the diachronic evolution, between 2001 and 2011, of their educational content around sustainable development. The analysis leads to a reflection on the specificity of French contexts, compared to international positions. Indeed, the legitimacy of the education provided is queried against the economization of the educational sphere. Didactic problems are posed by the reduction of distances between social practices and knowledge mobilized for the teachings. The evolution of the ‘school form’ and the specific place of ‘educations for’ in the framework of the institution are questioned. 相似文献
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Thomas K. Bader Karin de Borst Karin Fackler Thomas Ters Susan Braovac 《Journal of Cultural Heritage》2013,14(5):377-388
Mechanical properties of wood at different length scales of its hierarchical structure are governed by structural and compositional properties on smaller length scales. This opens up the possibility to use microstructural data for estimating mechanical properties, which are difficult to assess by conventional, destructive testing but are nevertheless of high relevance for conservation practice. Herein, we investigate such microstructure-mechanics relationships for a particular example, namely the load bearing archaeological oak of the Oseberg Viking ship, displayed at the Viking Ship Museum in Oslo, Norway. In order to identify the effects of degradation on the mechanical behavior and their relations to the microstructure, recent oak specimens of different geographical origin (Norway and Austria) are investigated as well. Wood exhibits a cellular structure. Its cell walls are composed of an amorphous polymer matrix consisting of lignin and hemicelluloses and embedded, stiff cellulose fibers. At the cell level, experimental studies comprised microscopic investigations of the cellular structure, chemical analyses of the composition of the cell walls, as well as nanoindentation tests on single cell walls. The same samples were also analyzed on the macroscopic level, where additionally mass density and annual ring data were measured together with ultrasonic stiffnesses. The chemical data clearly indicate deterioration in the archaeological oak, affecting mainly hemicelluloses and amorphous cellulose. At the cell wall scale, however, this does not necessarily lead to a weaker material behavior. The nanoindentation modulus, as a measure of the cell wall stiffness, was found to even increase. This is counterintuitive to our understanding of the effects of chemical degradation. It might be due to possible modification of lignin in the Oseberg oak, and thus have a stronger effect on the indentation modulus than the concurrent weakening of the interfaces between the load-carrying cellulose fibers and the connecting cell wall matrix when analyzing wood at the microscopic level. A similar effect is also observed for the transversal stiffness of macroscopic samples, which increases. In tension-dominated loading modes, however, the degradation of the interfaces is the dominant effect, resulting for example in a considerable reduction of the macroscopic stiffness in longitudinal direction. This underlines the utmost relevance of the loading condition on the remaining load-carrying capacity of degraded wood. On the macroscale, effects of the geographical origin (i.e. growth conditions) on ring characteristics of the oak tissues override the effects of degradation on the mechanical behavior. They have to be carefully extracted in order to come up with conclusions on the effect of degradation from macroscopic test results. The identified microstructure-mechanics relationships provide the basis for–in further research steps–building mathematical models describing the relations between microstructural characteristics and macroscopic mechanical properties and, thereon, for structural analyses of historical wooden objects. 相似文献
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Rebekka Darner Gougis Janet F. Stomberg Alicia T. O’Hare Catherine M. O’Reilly Nicholas E. Bader Thomas Meixner Cayelan C. Carey 《International Journal of Science and Mathematics Education》2017,15(6):1039-1056
The concepts of randomness and variation are pervasive in science. The purpose of this study was to document how post-secondary life science students explain randomness and variation, infer relationships between their explanations, and ability to describe and identify appropriate and inappropriate variation, and determine if students can identify sources of variation. An instrument designed to test statistical concepts was administered to 282 college students from three universities, ranging from introductory non-science majors to science graduate students. Students readily distinguished between causes of variation. A naïve no-pattern concept of randomness persisted from first-year non-science majors to senior-level science majors, contributing to incorrect responses on the variation instrument. Students’ expressions of randomness were better predictors of performance on the variation instrument than their expressions of variation. It is argued that inclusion of everyday language uses of randomness in instruction can bridge the gap between vernacular and scientific uses of this term. 相似文献
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This paper describes a national survey designed to determine trends in videodisc use, development, and production in academic health sciences libraries throughout North America. In the winter of 1989, 131 four-page survey instruments went to library directors in academic health sciences institutions. Of these, 63 (48%) survey forms were completed and returned. Survey results indicated a wide range of videodisc technology use and development and a growing production of both Level I and Level III videodiscs within academic health sciences libraries. Videodisc technology delivery for student use was centralized within many medical libraries, although videodisc development was not centralized within academic health sciences centers. Most libraries (67%) have purchased videodisc technology and over one fourth (28%) are repurposing a videodisc within their institution. Over one fourth (25%) of respondents have already begun to develop their own videodisc software, and almost one fourth (24%) of respondents have a Level III videodisc in production. Clearly the use and development of videodisc technology for biomedical instruction is expanding within academic health sciences libraries. 相似文献