Effects of External Loads on Human Head Movement Control Systems

The central and reflexive control strategies underlying movements were elucidated by studying the effects of external loads on human head movement control systems. Some experimental results are presented on dynamic changes weigh the addition of aviation helmet (SPH4) and lead weights (6 kg). Intended time-optimal movements, their dynamics and electromyographic activity of neck muscles in normal movements, and also in movements made with external weights applied to the head were measured. It was observed that, when the external loads were added, the subject went through complex adapting processes and the head movement trajectory and its derivatives reached steady conditions only after transient adapting period. The steady adapted state was reached after 15 to 20 seconds (i.e., 5 to 6 movements)

Pathological Speech Classification Using a Convolutional Neural Network

Convolutional Neural Networks (CNNs) have enabled significant improvements across a number of applications in computer vision such as object detection, face recognition and image classification. An audio signal can be visually represented as a spectrogram that captures the time-varying frequency content of the signal. This paper describes how a CNN can be applied to the spectrogram of an audio signal to distinguish pathological from healthy speech. We propose a CNN structure and implement it using Keras to test the approach. A classification accuracy of over 95% is obtained in experiments on two public pathological speech datasets

High-efficiency WSi superconducting nanowire single-photon detectors for quantum state engineering in the near infrared

We report on high-efficiency superconducting nanowire single-photon detectors based on amorphous WSi and optimized at 1064 nm. At an operating temperature of 1.8 K, we demonstrated a 93% system detection efficiency at this wavelength with a dark noise of a few counts per second. Combined with cavity-enhanced spontaneous parametric down-conversion, this fiber-coupled detector enabled us to generate narrowband single photons with a heralding efficiency greater than 90% and a high spectral brightness of $0.6\times10^4$ photons/(s$\cdot$mW$\cdot$MHz). Beyond single-photon generation at large rate, such high-efficiency detectors open the path to efficient multiple-photon heralding and complex quantum state engineering

ELECTROMYOGRAPHY AND KINEMATIC CHARACTERISTICS OF OBSTACLE GAIT IN ELDERLY PARKINSON’S PATIENTS

INTRODUCTION: Falls associated with tripping over an obstacle can be dangerous, yet little is known about the strategies used for stepping over obstacles in elderly Parkinson's patients. The purpose of this study was to investigate the lower extremity muscle activity and kinematics of obstacle gait in Parkinson's patients

Short range ferromagnetism and spin glass state in Y0.7Ca0.3MnO3\mathrm{Y_{0.7}Ca_{0.3}MnO_{3}}

Dynamic magnetic properties of $\mathrm{Y_{0.7}Ca_{0.3}MnO_{3}}$ are reported. The system appears to attain local ferromagnetic order at $T_{\mathrm{SRF}} \approx 70$ K. Below this temperature the low field magnetization becomes history dependent, i.e. the zero field cooled (ZFC) and field cooled (FC) magnetization deviate from each other and closely logarithmic relaxation appears at our experimental time scales (0.3-$10^{4}$ sec). The zero field cooled magnetization has a maximum at $T_{\mathrm{f}}\approx 30$ K, whereas the field cooled magnetization continues to increase, although less sharply, also below this temperature. Surprisingly, the dynamics of the system shows non-equilibrium spin glass (SG) features not only below the maximum in the ZFC magnetization, but also in the temperature region between this maximum and $T_{\mathrm{SRF}}$. The aging and temperature cycling experiments show only quantitative differences in the dynamic behavior above and below the maximum in the ZFC-magnetization; similarly, memory effects are observed in both temperature regions. We attribute the high temperature behavior to the existence of clusters of short range ferromagnetic order below $T_{\mathrm{SRF}}$; the configuration evolves into a conventional spin glass state at temperatures below $T_{\mathrm{f}}$.Comment: REVTeX style; 8 pages, 8 figure

Transition Spectra for a BCS Superconductor with Multiple Gaps: Model Calculations for MgB_2

We analyze the qualitative features in the transition spectra of a model superconductor with multiple energy gaps, using a simple extension of the Mattis-Bardeen expression for probes with case I and case II coherence factors. At temperature T = 0, the far infrared absorption edge is, as expected, determined by the smallest gap. However, the large thermal background may mask this edge at finite temperatures and instead the secondary absorption edges found at Delta_i+Delta_j may become most prominent. At finite T, if certain interband matrix elements are large, there may also be absorption peaks at the gap difference frequencies | Delta_i-Delta_j | . We discuss the effect of sample quality on the measured spectra and the possible relation of these predictions to the recent infrared absorption measurement on MgB_2

Selective dilution and magnetic properties of La_{0.7}Sr_{0.3}Mn_{1-x}M'_xO_3 (M' = Al, Ti)

The magnetic lattice of mixed-valence Mn ions in La$_{0.7}$Sr$_{0.3}$MnO$_3$ is selectively diluted by partial substitution of Mn by Al or Ti. The ferromagnetic transition temperature and the saturation moment decreases with substitution in both series. The volume fraction of the non-ferromagnetic phases evolves non-linearly with the substitution concentration and faster than theoretically expected. By presenting the data in terms of selective dilutions, the reduction of $T_\mathrm{c}$ is found to be scaled by the relative ionic concentrations and is consistent with a prediction derived from molecular-field theory.Comment: 6 pages, 5 figures, REVTex4.0. Submitted to PR

The optical response of Ba_{1-x}K_xBiO_3: Evidence for an unusual coupling mechanism of superconductivity?

We have analysed optical reflectivity data for Ba_{1-x}K_xBiO_3 in the far-infrared region using Migdal-Eliashberg theory and found it inconsistent with standard electron-phonon coupling: Whereas the superconducting state data could be explained using moderate coupling, \lambda=0.7, the normal state properties indicate \lambda \le 0.2. We have found that such behaviour could be understood using a simple model consisting of weak standard electron-phonon coupling plus weak coupling to an unspecified high energy excitation near 0.4 eV. This model is found to be in general agreement with the reflectivity data, except for the predicted superconducting gap size. The additional high energy excitation suggests that the dominant coupling mechanism in Ba_{1-x}K_xBiO_3 is not standard electron-phonon.Comment: 5 pages REVTex, 5 figures, 32 refs, accepted for publication in Phys. Rev.