465 research outputs found
RELIABILITY AND VALIDITY OF LASER DISTANCE AND VELOCITY DETERMINATION DURING RUNNING
This study compared the reliability of the laser system with video based kinematic analysis in measuring displacement and velocity. Validity and reliability of the laser on static measures was also assessed at distances between 10m and 70m. Ten subjects completed three running trials at self-determined fast, medium and slow speeds. Running velocity was measured simultaneously by a laser and two video cameras (one at 50Hz, one at 100Hz) within a 3m measurement zone. The reliability of velocity measurements for the 50Hz and 100Hz cameras via intra-class correlation were estimated at R=0.984 (confidence interval 0.95>0.971 to 0.992) and R=0.981 (confidence interval 0.95>0.966 to 0.991) respectively. For the laser, reliability was estimated at R=0.986 (confidence interval 0.95>0.975 to 0.993). One-way repeated measures ANOVA indicated no significant differences (p>0.05) between the three trials for any device. Measurement of running velocity using this procedure was deemed to be valid and reliable
FUNCTIONAL DATA ANALYSIS OF THE KINEMATICS OF GAIT IN SUBJECTS WITH A HISTORY OF ACHILLES TENDON INJURY
Clinical biomechanics research aims to understand the mechanisms of injury to improve prediction, prevention and rehabilitation. Dynamical systems theory suggests that coordination and variability may be key issues in the development of injuries. Traditional analysis has relied on a multivariate approach using discrete measures during stance. This essentially discards kinematic data obtained throughout the entire stance phase. Functional data analysis is an established statistical technique that is now emerging in biomechanics. It views the data as a function, thus using the entire time series data and determines which factors contribute to the variation. The purpose of this study was to examine the predictions of dynamical systems theory on angular kinematic data in subjects with Achilles tendon injury using a functional data analysis approach
ORTHOSES CONTROL OF FRONTAL AND SAGITTAL PLANE MOTION IN THE INJURED AND UNINJURED LEGS OF SUBJECTS WITH CHRONIC ACHILLES TENDON INJURY DURING RUNNING
This study is part of a larger study examining the effectiveness of orthoses in relieving symptoms of injury. Nine subjects with unilateral chronic Achilles tendon injury ran on a treadmill under three conditions: barefoot, with orthoses and without orthoses. Threedimensional rearfoot and lower leg kinematic data was obtained using eight ProReflex Qualisys MCU240 cameras operating at 200 Hz. An SPSS repeated measures ANOVA was used to examine differences between injured and uninjured legs. Results indicated considerable between SUbject variation even in this carefUlly controlled SUbject group. Orthoses restored the injured leg to a more neutral frontal plane position at heel strike and decreased sagittal plane maximum and ROM angles by more than 2° compared to the no orthoses condition. There was a significant leg'condition interaction effect for Achilles tendon angle at heel strike (p =0.003) illustrating different effects of conditions for both legs
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A Framework for Exploring Functional Variability in Olfactory Receptor Genes
Background: Olfactory receptors (ORs) are the largest gene family in mammalian genomes. Since nearly all OR genes are orphan receptors, inference of functional similarity or differences between odorant receptors typically relies on sequence comparisons. Based on the alignment of entire coding region sequence, OR genes are classified into families and subfamilies, a classification that is believed to be a proxy for OR gene functional variability. However, the assumption that overall protein sequence diversity is a good proxy for functional properties is untested.Methodology: Here, we propose an alternative sequence-based approach to infer the similarities and differences in OR binding capacity. Our approach is based on similarities and differences in the predicted binding pockets of OR genes, rather than on the entire OR coding region.Conclusions: Interestingly, our approach yields markedly different results compared to the analysis based on the entire OR coding-regions. While neither approach can be tested at this time, the discrepancy between the two calls into question the assumption that the current classification reliably reflects OR gene functional variability.</p
Sound-Induced Flash Illusion is Resistant to Feedback Training
A single flash accompanied by two auditory beeps tends to be perceived as two flashes (Shams et al. Nature 408:788, 2000, Cogn Brain Res 14:147–152, 2002). This phenomenon is known as ‘sound-induced flash illusion.’ Previous neuroimaging studies have shown that this illusion is correlated with modulation of activity in early visual cortical areas (Arden et al. Vision Res 43(23):2469–2478, 2003; Bhattacharya et al. NeuroReport 13:1727–1730, 2002; Shams et al. NeuroReport 12(17):3849–3852, 2001, Neurosci Lett 378(2):76–81, 2005; Watkins et al. Neuroimage 31:1247–1256, 2006, Neuroimage 37:572–578, 2007; Mishra et al. J Neurosci 27(15):4120–4131, 2007). We examined how robust the illusion is by testing whether the frequency of the illusion can be reduced by providing feedback. We found that the sound-induced flash illusion was resistant to feedback training, except when the amount of monetary reward was made dependent on accuracy in performance. However, even in the latter case the participants reported that they still perceived illusory two flashes even though they correctly reported single flash. Moreover, the feedback training effect seemed to disappear once the participants were no longer provided with feedback suggesting a short-lived refinement of discrimination between illusory and physical double flashes rather than vanishing of the illusory percept. These findings indicate that the effect of sound on the perceptual representation of visual stimuli is strong and robust to feedback training, and provide further evidence against decision factors accounting for the sound-induced flash illusion
Giant magnetic anisotropy changes in Sr2CrReO6 thin films on BaTiO3
The integration of ferromagnetic and ferroelectric materials into hybrid
heterostructures yields multifunctional systems with improved or novel
functionality. We here report on the structural, electronic and magnetic
properties of the ferromagnetic double perovskite Sr2CrReO6, grown as epitaxial
thin film onto ferroelectric BaTiO3. As a function of temperature, the
crystal-structure of BaTiO3 undergoes phase transitions, which induce
qualitative changes in the magnetic anisotropy of the ferromagnet. We observe
abrupt changes in the coercive field of up to 1.2T along with resistance
changes of up to 6.5%. These results are attributed to the high sensitivity of
the double perovskites to mechanical deformation.Comment: 3 figure
Tuning morphology and magnetism in epitaxial L10-FePt films
In this work, well-ordered epitaxial FePt thin ¿lms have been grown by RF sputtering on two different substrates (MgO (100) and SrTiO3 (100)) and the effect of different lattice parameters between the substrate and FePt ¿lm on morphology and magnetic behavior has been considered. Growth conditions have been optimized to obtain different morphologies and magnetic behaviors
Origin of the giant magnetic moment in epitaxial Fe3O4 thin films
7 páginas, 7 figuras.-- PACS number(s): 75.70.Rf, 75.70.Ak, 75.50.Bb.-- et al.We study the enhanced magnetic moment observed in epitaxial magnetite (Fe3O4) ultrathin films (t<15 nm) grown on MgO (001) substrates by means of pulsed laser deposition. The Fe3O4 (001) thin films exhibit high crystallinity, low roughness, and sharp interfaces with the substrate, and the existence of the Verwey transition at thicknesses down to 4 nm. The evolution of the Verwey transition temperature with film thickness shows a dependence with the antiphase boundaries density. Superconducting quantum interference device (SQUID) and vibrating sample magnetometry measurements in ultrathin films show a magnetic moment much higher than the bulk magnetite value. In order to study the origin of this anomalous magnetic moment, polarized neutron reflectivity (PNR), and x-ray magnetic circular dichroism (XMCD) experiments have been performed, indicating a decrease in the magnetization with decreasing sample thickness. X-ray photoemission spectroscopy measurements show no metallic Fe clusters present in the magnetite thin films. Through inductively coupled plasma mass spectroscopy and SQUID magnetometry measurements performed in commercial MgO (001) substrates, the presence of Fe impurities embedded within the substrates has been observed. Once the substrate contribution has been corrected, a decrease in the magnetic moment of magnetite thin films with decreasing thickness is found, in good agreement with the PNR and XMCD measurements. Our experiments suggest that the origin of the enhanced magnetic moment is not intrinsic to magnetite but due to the presence of Fe impurities in the MgO substrates.This work has been financially supported
by Spanish Ministry of Science through Projects No.
MAT2008-06567-C02 and No. MAT2008-01077, and the
Regional Government of Aragón (E-26, E-69, and E-34).Peer reviewe
La reedición de la discusión de la pena de muerte en América Latina
Desde la Antigüedad la pena de muerte es aplicada como castigo análogo a la acción cometida contra la vida y los credos religiosos. La religión había asimilado esta sanción como una forma de salvaguardar a los no pecadores, de aquellas personas consideradas como peligrosas para la fe. Su discusión es de larga data y las posiciones a favor y en contra, siempre se han hecho presentes. En América Latina, los altos índices de criminalidad llevan a que sectores sociales exijan se discuta sobre la necesidad de la aplicación de la pena capital, como forma de combatir la inseguridad, lo que desde lo teórico contrapone las teorías retributivas y utilitarias, así como la normativa internacional en materia de protección de derechos humanos.Since ancient times, death penalty has been applied as a punishment that deserves those who attempt against life and against religious beliefs. Religion had assimilated this sanction as a way to preserve it from sinners, people considered as dangerous for faith. This discussion is long-standing and the arguments for and against have always been present. In Latin America, the high crime rates lead social sectors to demand a new discussion about the need of apply a death penalty as a way to fight the climate of insecurity, position that contrast with retributive and utilitarian theories, as well as international law in human rights
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