4,668 research outputs found
Dynamics of fluctuations in a quantum system
"\textit{The noise is the signal}"[R. Landauer, Nature \textbf{392}, 658
(1998)] emphasizes the rich information content encoded in fluctuations. This
paper assesses the dynamical role of fluctuations of a quantum system driven
far from equilibrium, with laser-aligned molecules as a physical realization.
Time evolutions of the expectation value and the uncertainty of a standard
observable are computed quantum mechanically and classically. We demonstrate
the intricate dynamics of the uncertainty that are strikingly independent of
those of the expectation value, and their exceptional sensitivity to quantum
properties of the system. In general, detecting the time evolution of the
fluctuations of a given observable provides information on the dynamics of
correlations in a quantum system.Comment: 6 pages, 2 figure
RELATIONSHIP BETWEEN THE KINEMATICS OF THE TRUNK AND LOWER EXTREMITIES AND BALL VELOCITY DURING THE OVERHAND THROW IN MALE CANOE POLO PLAYERS
The purpose of this study was to examine the relationship between the motion of the trunk and lower extremities and ball velocity during the overhand throw in canoe polo. Fifteen male national canoe polo team players participated in this study. The overhand throwing motion was captured using a three dimensional motion analysis system. Kinematic and temporal parameters in the trunk and lower extremities were measured and analyzed. Results indicated that five variables were associated with variations in ball velocity. Specifically, as ball velocity increased, canoe polo players showed an increased maximal angular velocity in trunk-tilt sideways, upper torso rotation, and right knee flexion. In addition, the right knee flexion range of motion and time to maximum right knee flexion angular velocity increased as ball velocity increased
Revisiting the problem of audio-based hit song prediction using convolutional neural networks
Being able to predict whether a song can be a hit has impor- tant
applications in the music industry. Although it is true that the popularity of
a song can be greatly affected by exter- nal factors such as social and
commercial influences, to which degree audio features computed from musical
signals (whom we regard as internal factors) can predict song popularity is an
interesting research question on its own. Motivated by the recent success of
deep learning techniques, we attempt to ex- tend previous work on hit song
prediction by jointly learning the audio features and prediction models using
deep learning. Specifically, we experiment with a convolutional neural net-
work model that takes the primitive mel-spectrogram as the input for feature
learning, a more advanced JYnet model that uses an external song dataset for
supervised pre-training and auto-tagging, and the combination of these two
models. We also consider the inception model to characterize audio infor-
mation in different scales. Our experiments suggest that deep structures are
indeed more accurate than shallow structures in predicting the popularity of
either Chinese or Western Pop songs in Taiwan. We also use the tags predicted
by JYnet to gain insights into the result of different models.Comment: To appear in the proceedings of 2017 IEEE International Conference on
Acoustics, Speech and Signal Processing (ICASSP
Decrease of Klotho in the Kidney of Streptozotocin-Induced Diabetic Rats
The klotho gene is expressed in a limited number of tissues, most notably in distal convoluted tubules in the kidney and choroid plexus in the brain. A previous study suggested that Klotho increases resistance to oxidative stress. However, changes of Klotho expression in high glucose-induced oxidative stress remain unclear. In the present study, we used streptozotocin-induced diabetic rats (STZ rats) to examine the effects of insulin, phloridzin or antioxidant, tiron on diabetic nephropathy. Both insulin and phloridzin reversed the lower Klotho expression levels in kidneys of STZ rats by the correction of hyperglycemia. Also, renal functions were improved by these treatments. In addition to the improvement of renal functions, the decrease of Klotho expression in kidney of STZ rats was also reversed by tiron without changing blood glucose levels. The reduction of oxidative stress induced by high glucose can be considered for this action of tiron. This view was further confirmed in vitro using high glucose-exposed Madin-Darby canine kidney (MDCK) epithelial cells. Thus, we suggest that decrease of oxidative stress is not only responsible for the improvement of renal function but also for the recovery of Klotho expression in kidney of STZ rats
- …