1,753 research outputs found
A KINEMATIC STUDY OF BUTTERFLY TURN IN ELITE SWIMMERS
The aims of this work were (i) to evaluate the different phases of the butterfly turn during a 200 m race (in long course), (ii) to determine if the wall contact times were related to swim velocity, (iii) to compare the turn variables of the European champion with the other swimmers studied. Two studies were carried out, the first one was to: (i) test 22 swimmers ranked in 3 groups according to their performance. The most significant results revealed that the third turn was performed quicker by GI (the faster group) than by G3 (the slower group), both before (
Group-level Emotion Recognition using Transfer Learning from Face Identification
In this paper, we describe our algorithmic approach, which was used for
submissions in the fifth Emotion Recognition in the Wild (EmotiW 2017)
group-level emotion recognition sub-challenge. We extracted feature vectors of
detected faces using the Convolutional Neural Network trained for face
identification task, rather than traditional pre-training on emotion
recognition problems. In the final pipeline an ensemble of Random Forest
classifiers was learned to predict emotion score using available training set.
In case when the faces have not been detected, one member of our ensemble
extracts features from the whole image. During our experimental study, the
proposed approach showed the lowest error rate when compared to other explored
techniques. In particular, we achieved 75.4% accuracy on the validation data,
which is 20% higher than the handcrafted feature-based baseline. The source
code using Keras framework is publicly available.Comment: 5 pages, 3 figures, accepted for publication at ICMI17 (EmotiW Grand
Challenge
EFFECT OF SWIM PADDLES ON THE INTRA-CYCLIC VELOCITY VARIATIONS AND ON THE ARM COORDINATION OF FRONT CRAWL STROKE
This study analysed the effect of swimming with hand paddles on arm coordination and velocity pattern. Eight competitive swimmers performed two maximal aerobic tests. The maximal aerobic velocity was significantly higher when swimming with paddles but stroke rate, maximal heart rate and blood lactate values did not differ. The index of coordination (IdC) determined according to Chollet et al. (2000) and the intra-cyclic velocity variations were measured in two 25 m tests, one with and one without swim paddles, at a fixed stroke rate. When swimming with paddles, IdC and the duration of the propulsive phase increased significantly (~~0.0a5n)d the velocity signal frequency spectrum showed fewer harmon~cs (
Diffraction based Hanbury Brown and Twiss interferometry performed at a hard x-ray free-electron laser
We demonstrate experimentally Hanbury Brown and Twiss (HBT) interferometry at
a hard X-ray Free Electron Laser (XFEL) on a sample diffraction patterns. This
is different from the traditional approach when HBT interferometry requires
direct beam measurements in absence of the sample. HBT analysis was carried out
on the Bragg peaks from the colloidal crystals measured at Linac Coherent Light
Source (LCLS). We observed high degree (80%) spatial coherence of the full beam
and the pulse duration of the monochromatized beam on the order of 11 fs that
is significantly shorter than expected from the electron bunch measurements.Comment: 32 pages, 10 figures, 2 table
C/C ratio in planetary nebulae from the IUE archives
We investigated the abundance ratio of C/C in planetary nebulae
by examining emission lines arising from \ion{C}{3} 2s2p ^3P_{2,1,0} \to 2s^2
^1S_0. Spectra were retrieved from the International Ultraviolet Explorer
archives, and multiple spectra of the same object were coadded to achieve
improved signal-to-noise. The C hyperfine structure line at 1909.6 \AA
was detected in NGC 2440. The C/C ratio was found to be
1.2. In all other objects, we provide an upper limit for the flux
of the 1910 \AA line. For 23 of these sources, a lower limit for the
C/C ratio was established. The impact on our current
understanding of stellar evolution is discussed.
The resulting high signal-to-noise \ion{C}{3} spectrum helps constrain the
atomic physics of the line formation process. Some objects have the measured
1907/1909 flux ratio outside the low-electron density theoretical limit for
C. A mixture of C with C helps to close the gap somewhat.
Nevertheless, some observed 1907/1909 flux ratios still appear too high to
conform to the presently predicted limits. It is shown that this limit, as well
as the 1910/1909 flux ratio, are predominantly influenced by using the standard
partitioning among the collision strengths for the multiplet --
according to the statistical weights. A detailed calculation for the fine
structure collision strengths between these individual levels would be
valuable.Comment: ApJ accepted: 19 pages, 3 Figures, 2 Table
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