11,414 research outputs found
Moreau\u27s Effective Intercultural Communication: A Christian Perspectives (Book Review)
Keel and Schroer\u27s Creation; Biblical theologies in the context of the ancient Near East (Book Review)
A review of Keel, O., & Schroer, S. (2015). Creation; Biblical theologies in the context of the ancient Near East (Peter T. Daniels, Trans.). Winona Lake, IN: Eisenbrauns, 244 pp. $44.99. ISBN 978157506093
Coppenger\u27s Moral Apologetics for Contemporary Christians: Pushing Back Against Cultural and Religious Critics (Book Review)
Necessity to adapt land use and land cover classification systems to readily accept radar data
A hierarchial, four level, standardized system for classifying land use/land cover primarily from remote-sensor data (USGS system) is described. The USGS system was developed for nonmicrowave imaging sensors such as camera systems and line scanners. The USGS system is not compatible with the land use/land cover classifications at different levels that can be made from radar imagery, and particularly from synthetic-aperture radar (SAR) imagery. The use of radar imagery for classifying land use/land cover at different levels is discussed, and a possible revision of the USGS system to more readily accept land use/land cover classifications from radar imagery is proposed
The effects of fatigue on race walking technique
The purpose of this study was to measure the effects of fatigue on gait parameters during race walking. Research has shown that fatigued athletes require gait alterations in order to maintain speed. Eighteen competitive race walkers walked either 5 km or 10 km at a pace equivalent to 105% of their season’s best time. Junior athletes walked 5 km, while senior athletes (mostly 20 km walkers) walked 10 km. Kinetic data were collected using a Gaitway treadmill (1000 Hz). Data were collected at three points during the 5 km walks and at four points during the 10 km walks. Repeated measures ANOVA showed that there were significant differences in impulse and contact time parameters (p < .01). The kinetic and temporal changes occurred as early as 1 km. Athletes are recommended to race at a constant pace to reduce the effects of fatigue
The measurement of kinetic variables in race walking
The purpose of this study was to measure kinetic variables during race walking. Forty national and international race walkers walked either 5 km or 10 km at a pace equivalent to 105% of their season’s best time. Junior athletes walked 5 km, while senior athletes (mostly 20 km walkers) walked 10 km. Kinetic data were collected using a Gaitway treadmill (1000 Hz). Data were collected at the 2.5 km point. Men had longer step lengths than women and walked faster as a result. There was little difference in cadence. Average flight times for each group of athlete were approximately 0.04 s. Senior athletes showed more ‘typical’ race walking vertical force patterns than the juniors; this may be linked to quantity of training experience and gait efficiency. Athletes are advised to develop muscular strength endurance to cope with loading rates upon initial contact
A Fast and Accurate Algorithm for Spherical Harmonic Analysis on HEALPix Grids with Applications to the Cosmic Microwave Background Radiation
The Hierarchical Equal Area isoLatitude Pixelation (HEALPix) scheme is used
extensively in astrophysics for data collection and analysis on the sphere. The
scheme was originally designed for studying the Cosmic Microwave Background
(CMB) radiation, which represents the first light to travel during the early
stages of the universe's development and gives the strongest evidence for the
Big Bang theory to date. Refined analysis of the CMB angular power spectrum can
lead to revolutionary developments in understanding the nature of dark matter
and dark energy. In this paper, we present a new method for performing
spherical harmonic analysis for HEALPix data, which is a central component to
computing and analyzing the angular power spectrum of the massive CMB data
sets. The method uses a novel combination of a non-uniform fast Fourier
transform, the double Fourier sphere method, and Slevinsky's fast spherical
harmonic transform (Slevinsky, 2019). For a HEALPix grid with pixels
(points), the computational complexity of the method is , with an initial set-up cost of . This compares
favorably with runtime complexity of the current methods
available in the HEALPix software when multiple maps need to be analyzed at the
same time. Using numerical experiments, we demonstrate that the new method also
appears to provide better accuracy over the entire angular power spectrum of
synthetic data when compared to the current methods, with a convergence rate at
least two times higher
Gait parameter differences between the legs during race walking
Prior research on the effects of fatigue during race walking has shown changes in step length and frequency (Knicker & Loch, 1990: New Studies in Athletics, 5, 25–38). It is unclear whether these changes are consistent for both legs. The purpose of the study was to investigate the differences between the legs for kinetic variables during race walking, and to measure changes occurring because of fatigue. The study was approved by the university’s ethics committee and informed consent was given by fourteen international race walkers, of whom four were females (age mean 28.2, s=7.4 years; stature 1.77, s=0.10 m; mass 66.0, s=11.7 kg). Each participant walked for 10 km on a treadmill (Gaitway, Traunstein). The average treadmill speed was 12.4 km h-1 (s=0.7) and each athlete walked at a constant pace. Data were recorded using the Gaitway treadmill, which has two in-dwelling force plates (Kistler, Winterthur). The sampling rate was 1000 Hz. Data were collected for 30 s at four times during the walk, at 2500 m, 4500 m, 6500 m and 8500 m. Statistical analysis consisted of repeated measures ANOVA. There was a significant difference between the legs for first peak force (F1,13=32.6, P¼0.001, Z2=0.71, power=0.99), weight acceptance rate (F1,13=14.5, P=.002, Z2=0.53, power=0.94), and push-off rate (F1,13=36.2, P=0.001, Z2=0.74, power=1), although these differences did not change significantly with distance walked. There was also a significant difference between the legs’ step lengths (F1,13=30.1, P=0.001, Z2=0.70, power=0.99), midsupport forces (F1,13=9.6, P=0.009, Z2=0.42, power=0.82), and propulsive force peaks (F1,13=20.6, P=0.001, Z2=0.61, power=0.99); the overall values for these variables also increased significantly with distance walked (P<0.001, P=0.009, and P<0.001 respectively). However, there was no effect of distance on the differences between the legs for any variable. The results show significant leg dominance during race walking. Athletes should be aware that these imbalances need rectification to prevent injury and maintain efficient walking technique. The imbalances did not appear to worsen with the onset of fatigue although this may occur over the longer championship distances of 20 and 50 km
Muscle activity of the stance knee in elite race walkers
The purpose of this study was to compare knee muscle activity in race walkers with different knee extension patterns. Three international athletes walked over two force plates recording at 1000 Hz. Video data were simultaneously recorded at 100 Hz; the digitised data were combined with the force data to calculate net muscle moments and joint powers. EMG testing was carried out on three muscles which cross the knee. The two walkers with legal techniques had similar moment and power patterns, whereas the non-legal walker experienced a longer period of eccentric flexor moment at the beginning of stance, which may have affected his ability to extend his knee correctly. After this, all three athletes experienced a period of isometric contraction at the knee. Achieving correct technique requires both strength endurance exercises and mobility development
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