20,791 research outputs found
The effects of shoe temperature on the kinetics and kinematics of running
The aim of the current investigation was to examine the effects of cooled footwear on the kinetics and kinematics of running in comparison to footwear at normal temperature. Twelve participants ran at 4.0 m/s ± 5% in both cooled and normal temperature footwear conditions over a force platform. Two identical footwear were worn, one of which was cooled for 30 min. Lower extremity kinematics were obtained using a motion capture system and tibial accelerations were measured using a triaxial accelerometer. Differences between cooled and normal footwear temperatures were contrasted using paired samples t-tests. The results showed that midsole temperature (cooled = 4.21 °C and normal = 23.25 °C) and maximal midsole deformation during stance (cooled = 12.85 mm and normal = 14.52 mm) were significantly reduced in the cooled footwear. In addition, instantaneous loading rate (cooled = 186.21 B.W/s and normal = 167.08 B W/s), peak tibial acceleration (cooled = 12.75 g and normal = 10.70 g) and tibial acceleration slope (cooled = 478.69 g/s and normal = 327.48 g/s) were significantly greater in the cooled footwear. Finally, peak eversion (cooled = −10.57 ° and normal = −7.83°) and tibial internal rotation (cooled = 10.67 ° and normal = 7.77°) were also shown to be significantly larger in the cooled footwear condition. This study indicates that running in cooled footwear may place runners at increased risk from the biomechanical parameters linked to the aetiology of injuries
The polar temperature of Venus
Interferometric and polarization measurements of polar regions of Venu
Automatic focus control for facsimile cameras
An electronic circuit for controlling the focus of facsimile cameras is described. The circuit consists of balanced a.c. amplifiers, two square law function generators, and a differential amplifier and power drive. The invention includes a method for maintaining the imaging sensor at the expected location of the focal plane as the facsimile camera scans a scene or terrain. A block diagram of the electronic circuitry is provided
Bose-Einstein Condensation on a Permanent-Magnet Atom Chip
We have produced a Bose-Einstein condensate on a permanent-magnet atom chip
based on periodically magnetized videotape. We observe the expansion and
dynamics of the condensate in one of the microscopic waveguides close to the
surface. The lifetime for atoms to remain trapped near this dielectric material
is significantly longer than above a metal surface of the same thickness. These
results illustrate the suitability of microscopic permanent-magnet structures
for quantum-coherent preparation and manipulation of cold atoms.Comment: 4 pages, 6 figures, Published in Phys. Rev. A, Rapid Com
Bose-Einstein Condensation on a Permanent-Magnet Atom Chip
We have produced a Bose-Einstein condensate on a permanent-magnet atom chip
based on periodically magnetized videotape. We observe the expansion and
dynamics of the condensate in one of the microscopic waveguides close to the
surface. The lifetime for atoms to remain trapped near this dielectric material
is significantly longer than above a metal surface of the same thickness. These
results illustrate the suitability of microscopic permanent-magnet structures
for quantum-coherent preparation and manipulation of cold atoms.Comment: 4 pages, 6 figures, Published in Phys. Rev. A, Rapid Com
Tunable quantum spin liquidity in the 1/6th-filled breathing kagome lattice
We present measurements on a series of materials,
LiInScMoO, that can be described as a 1/6th-filled
breathing kagome lattice. Substituting Sc for In generates chemical pressure
which alters the breathing parameter non-monotonically. SR experiments
show that this chemical pressure tunes the system from antiferromagnetic long
range order to a quantum spin liquid phase. A strong correlation with the
breathing parameter implies that it is the dominant parameter controlling the
level of magnetic frustration, with increased kagome symmetry generating the
quantum spin liquid phase. Magnetic susceptibility measurements suggest that
this is related to distinct types of charge order induced by changes in lattice
symmetry, in line with the theory of Chen et al. [Phys. Rev. B 93, 245134
(2016)]. The specific heat for samples at intermediate Sc concentration and
with minimal breathing parameter, show consistency with the predicted
quantum spin liquid.Comment: Accepted for publication in Physical Review Letter
Le Conseil économique et l’impact régional de la politique commerciale
Given that there are a number of possible models of the regional impact of a tariff, one would have hoped that the Council would have attempted to test the standard ones and/or to have developed new and better ones. After almost forty years Mackintosh's model is still probably the most persuasive model of the long run impact of the tariff in Canada. The Council in its main report has been largely content to repeat and to some extent to confuse elements of the conventional wisdom on the subject. Interesting points have been made in some of the background studies, particularly, among the studies reviewed, by Postner and by Dauphin.
- …
