1,359 research outputs found
REAL-TIME FEEDBACK OF PEDAL FORCES FOR THE OPTIMIZATION OF PEDALING TECHNIQUE IN COMPETITIVE CYCLING
INTRODUCTION: It seems doubtful that performance in road cycling can be improved by increasing the amount or intensity of training. Competitive cyclists already ride between 35,000 - 50,000 km per year as it is, the average daily time spent in the saddle being around 6 hours. An alternative means of increasing performance is to refine pedaling technique, so that a greater proportion of the energy used goes into forward propulsion. The same amount of energy is expended whilst riding speed is increased, or the amount of energy expended is reduced whilst retaining the same speed.
METHODS: The pedal forces are measured by triple-axis piezo force measuring elements, which can be integrated into LOOK-compatible cycle pedals. Crank angle and pedal angle are measured by special potentiometers. All measured variables are transmitted on-line to a PC for further processing. Speeds and angles of incline can be set on the treadmill used in the test. A computer monitor displays the feedback signal in real-time, whereby either the tangential force, the radial force or efficiency at that moment, i.e., the ratio between tangential force and that resulting, can be presented. Twelve competition cyclists took part in the tests. Each trial, at a rate of 200W and a pedaling frequency of 60 rpm, lasted 30 minutes and was broken down into three 10-minute periods. No feedback was given during the first 5 minutes, one of the respective parameters mentioned above was given as feedback in the second 5 minute period.
RESULTS: Comparing the phases without feedback to the three periods with feedback, efficiency of pedaling action increases significantly from 50% to 60%. A differentiated view emerges when one compares the effect of feedback in the various sectors of the crank circle and in relation to the various feedback parameters. In the area of the lower dead-point and during the pull-up phase, efficiency was raised on average over the three parameters by a significant 15% and 62% respectively. Feedback of radial forces produced the smallest improvement.
CONCLUSIONS: Refinement of pedaling technique with regard to higher efficiency of forward propulsion using the means of visual feedback in real-time promises improved results. The sports cyclists who took part in the tests were unanimous in believing that the feedback on pedal forces gave them fresh insight into their pedaling action. Requests were made for the regular use of feedback during training sessions. One could mention the development of a technique model in competitive cycling as another possible use of feedback. In this case, however, it would be necessary to consider overall energy efficiency at the same time. A further requirement is that the athlete’s muscular system can adapt to the new training conditions
Outcome Study of Physical Therapy Rehabilitation of Patients with Patellar Femoral Dysfunction
This study was conducted to assist St. Alexius Medical Center\u27s Institute of Sports Medicine in the analysis of physical therapy outcomes for patients who underwent patellofemoral surgical procedures including lateral retinacular release, vastus medialis oblique advancement, and tibial tubercle transfers. A review of data collected by the physical therapists at St. Alexius was performed and statistically analyzed to determine the efficacy of outcomes both clinically and functionally. This outcome analysis will assist current and future practice patterns by providing a basis for clinical effectiveness. The results of this study will be a useful resource for the facility as a guide to ensure quality improvement and as a tool for quantifying treatment to third party payers.
Overall, satisfactory outcomes, as determined by predetermined goals, were obtained by all patients for all areas of rehabilitation. On average, knee range of motion was functional and within protocol goals with no differences noted secondary to surgical procedure or patient\u27s age. Pain was kept to a minimum and was found to have no correlation with the age of the patient or return of strength. Joint effusion was also within the protocol goals and showed no correlation with achieved range of motion. Functional assessment demonstrated satisfactory results, overall, with transfers, ambulation, and activities of daily living
Rapid Formation and Flexible Expression of Memories of Subliminal Word Pairs
Our daily experiences are incidentally and rapidly encoded as episodic memories. Episodic memories consist of numerous associations (e.g., who gave what to whom where and when) that can be expressed flexibly in new situations. Key features of episodic memory are speed of encoding, its associative nature, and its representational flexibility. Another defining feature of human episodic memory has been consciousness of encoding/retrieval. Here, we show that humans can rapidly form associations between subliminal words and minutes later retrieve these associations even if retrieval words were conceptually related to, but different from encoding words. Because encoding words were presented subliminally, associative encoding, and retrieval were unconscious. Unconscious association formation and retrieval were dependent on a preceding understanding of task principles. We conclude that key computations underlying episodic memory – rapid encoding and flexible expression of associations – can operate outside consciousness
Вопросы определения экономической эффективности глубокого регулирования напряжения дальних линий электропередач
Приведена методика определения эффективности внедрения ГРН на существующих линиях. Предложена формула, которую можно использовать для определения оптимального диапазона регулирования для существующих связей при различном характере их работы
A molecular approach combined with American Thyroid Association classification better stratifies recurrence risk of classic histology papillary thyroid cancer
Contextual processing of brightness and color in Mongolian gerbils
Brightness and color cues are essential for visually guided behavior. However, for rodents, little is known about how well they do use these cues. We used a virtual reality setup that offers a controlled environment for sensory testing to quantitatively investigate visually guided behavior for achromatic and chromatic stimuli in Mongolian gerbils (Meriones unguiculatus). In two-alternative forced choice tasks, animals had to select target stimuli based on relative intensity or color with respect to a contextual reference. Behavioral performance was characterized using psychometric analysis and probabilistic choice modeling. The analyses revealed that the gerbils learned to make decisions that required judging stimuli in relation to their visual context. Stimuli were successfully recognized down to Weber contrasts as low as 0.1. These results suggest that Mongolian gerbils have the perceptual capacity for brightness and color constancy
Industrieller 3D-Betondruck durch selektive Zementaktivierung - Verfahren, Material, Anwendungen
Die selektive Zementaktivierung (SCA) ist ein additives Fertigungsverfahren zur Herstellung von Bauteilen aus Beton. Die SCA gehört zu den Verfahren des selektiven Bindens, bei denen schüttfähiges Material (hier eine Trockenmischung aus Zement und Gesteinskörnung) in dünnen Schichten ausgebracht und durch Einbringen einer flüssigen Komponente (hier Wasser) selektiv gebunden wird. Verglichen mit anderen Verfahren der additiven Fertigung mit Beton sind bei der SCA sowohl die Auflösung als auch die geometrische Freiheit besonders hoch. ...Selective cement activation (SCA) is an additive manufacturing process for the fabrication of concrete elements. SCA belongs to the group of the selective binding processes in which bulk material (here a dry mixture of cement and aggregate) is spread in thin layers and selectively bound by applying a liquid component (here water). Compared to other additive manufacturing processes using concrete, both resolution and geometric freedom are particularly high with SCA. ..
Fully-automated root image analysis (faRIA)
High-throughput root phenotyping in the soil became an indispensable quantitative tool for the assessment of effects of climatic factors and molecular perturbation on plant root morphology, development and function. To efficiently analyse a large amount of structurally complex soil-root images advanced methods for automated image segmentation are required. Due to often unavoidable overlap between the intensity of fore- and background regions simple thresholding methods are, generally, not suitable for the segmentation of root regions. Higher-level cognitive models such as convolutional neural networks (CNN) provide capabilities for segmenting roots from heterogeneous and noisy background structures, however, they require a representative set of manually segmented (ground truth) images. Here, we present a GUI-based tool for fully automated quantitative analysis of root images using a pre-trained CNN model, which relies on an extension of the U-Net architecture. The developed CNN framework was designed to efficiently segment root structures of different size, shape and optical contrast using low budget hardware systems. The CNN model was trained on a set of 6465 masks derived from 182 manually segmented near-infrared (NIR) maize root images. Our experimental results show that the proposed approach achieves a Dice coefficient of 0.87 and outperforms existing tools (e.g., SegRoot) with Dice coefficient of 0.67 by application not only to NIR but also to other imaging modalities and plant species such as barley and arabidopsis soil-root images from LED-rhizotron and UV imaging systems, respectively. In summary, the developed software framework enables users to efficiently analyse soil-root images in an automated manner (i.e. without manual interaction with data and/or parameter tuning) providing quantitative plant scientists with a powerful analytical tool. © 2021, The Author(s)
Thermal regime of the Costa Rican convergent margin: 1. Along-strike variations in heat flow from probe measurements and estimated from bottom-simulating reflectors
21 pages, 9 figures, 1 tableThe thermal structure of convergent margins provides information related to the tectonics, geodynamics, metamorphism, and fluid flow of active plate boundaries. We report 176 heat flow measurements made with a violin bow style probe across the Costa Rican margin at the Middle America Trench. The probe measurements are collocated with seismic reflection lines. These seismic reflection lines show widespread distribution of bottom-simulating reflectors (BSRs). To extend the spatial coverage of heat flow measurements we estimate heat flow from the depth of BSRs. Comparisons between probe measurements and BSR-derived estimates of heat flow are generally within 10% and improve with distance landward of the deformation front. Together, these determinations provide new information on the thermal regime of this margin. Consistent with previous studies, the margin associated with the northern Nicoya Peninsula is remarkably cool. We define better the southern boundary of the cool region. The northern extent of the cool region remains poorly determined. A regional trend of decreasing heat flow landward of the deformation front is apparent, consistent with the downward advection of heat by the subducting Cocos Plate. High wave number variability at a scale of 5–10 km is significantly greater than the measurement uncertainty and is greater south of the northern Nicoya Peninsula. These heat flow anomalies vary between approximately 20 and 60 mW m−2 and are most likely due to localized fluid flow through mounds and faults on the margin. Simple one-dimensional models show that these anomalies are consistent with flow rates of 7–15 mm yr−1. Across the margin toe variability is significant and likely due to fluid flow through deformation structures associated with the frontal sedimentary prismThis research was support by an NSF award (OCE‐0637120) to R.N.H. We thank R. von Huene, P. Fulton, and G. Spinelli for helpful comments. Heat flow data acquisition was funded by the German Science Foundation (DFG) through grant Vi 133/7‐1 to H.V. and I.G. and the SFB 574 “Volatiles and fluids in subduction zones” at Christan‐Albrechts University, Kiel. This is a contribution of the Barcelona Center for Subsurface Imaging (Barcelona‐CSI) supported by the Kaleidoscope project of REPSOLPeer Reviewe
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