QCD Viscosity to Entropy Density Ratio in the Hadronic Phase

Shear viscosity (eta) of QCD in the hadronic phase is computed by the coupled Boltzmann equations of pions and nucleons in low temperatures and low baryon number densities. The eta to entropy density ratio eta/s maps out the nuclear gas-liquid phase transition by forming a valley tracing the phase transition line in the temperature-chemical potential plane. When the phase transition turns into a crossover, the eta/s valley gradually disappears. We suspect the general feature for a first-order phase transition is that eta/s has a discontinuity in the bottom of the eta/s valley. The discontinuity coincides with the phase transition line and ends at the critical point. Beyond the critical point, a smooth eta/s valley is seen. However, the valley could disappear further away from the critical point. The eta/s measurements might provide an alternative to identify the critical points.Comment: 16 pages, 4 figures. Minor typos corrected and references adde

A THREE-DIMENSIONAL ANALYSIS OF THE VOLLEYBALL ONE-FOOT JUMP SPIKE

INTRODUCTION: Since the Chinese National female volleyball team developed the one-foot jump spike technique during the 1980s, the high percentage of successful spiking has made the skill a powerful offensive weapon on volleyball courts all over the world. But no research has been done on the biomechanical analysis of the female one-foot jump spike. The purpose of this study was to describe the biomechanical characteristics of the techniques of the one-foot jump spike demonstrated by elite Taiwanese female players. METHODS: Four elite female players from the Taiwanese National Volleyball Team served as subjects. Their mean height, weight, and age (and variance) were 1.78 (0.03) m, 63.53 (.11) kg, and 21.50 (.58) years, respectively. Two Peak Performance high speed video cameras operating at 120Hz were synchronized to record the actions employed by the subjects in performing the one-foot jump spike. Three-dimensional object space co-ordinates of digitized image co-ordinates were obtained using a DLT algorithm and 19 calibration points in the video volume. RESULTS: [Table 1] The values of selected variables for the one-foot jump spike by the four female players were calculated (Table 1). The elite female one-foot jump spikers had a shorter takeoff time(0.198s) than the elite male two-foot spikers(0.308s).The female one-foot jump spikers also had a sharper approach angle(27 deg)then the elite male and female two-foot spikers(45- 60 deg) which made it harder for the opponent to block the ball. The results of this study provide valuable information for teachers and coaches teaching players to perform the one-foot jump spike. CONCLUSIONS: The results indicated that elite female one-foot jump spikers have a shorter takeoff time and a sharper approach angle then the elite male and female two-foot spikers, which contribute to the success of spiking

Detach and Adapt: Learning Cross-Domain Disentangled Deep Representation

While representation learning aims to derive interpretable features for describing visual data, representation disentanglement further results in such features so that particular image attributes can be identified and manipulated. However, one cannot easily address this task without observing ground truth annotation for the training data. To address this problem, we propose a novel deep learning model of Cross-Domain Representation Disentangler (CDRD). By observing fully annotated source-domain data and unlabeled target-domain data of interest, our model bridges the information across data domains and transfers the attribute information accordingly. Thus, cross-domain joint feature disentanglement and adaptation can be jointly performed. In the experiments, we provide qualitative results to verify our disentanglement capability. Moreover, we further confirm that our model can be applied for solving classification tasks of unsupervised domain adaptation, and performs favorably against state-of-the-art image disentanglement and translation methods.Comment: CVPR 2018 Spotligh

GOLF PUTTING GRIP DESIGN INFLUENCES ON PUTTING KINEMATICS

Putting is considered one of the most important skills in golf. Golf club designs have been consistenly introducing new design to enhance performance. The purpose of this paper was to look into the effects of grip sizes on putting kinematics. Ten (n=7) male, right-handed, novice-skilled golfers (height 172.4±3.4cm, weight 72.3±2.4kg, age 38.6 ±1.3yrs, and handicap 9.5 ±1.1) were recruited for the study. Research results suggest that larger grip design have affect on the kinematics of the putting characterics, with trait of shorter backswing, decrease in total rotation during downswing and shorterened rhythm &timing. Future study focuses on the cordinate change of body joints in relation to phase and relative club position, and synchronize with EMG data between various skill level

Random singlets and permutation symmetry in the disordered spin-2 Heisenberg chain: A tensor network renormalization group study

We use a tensor network renormalization group method to study random $S=2$ antiferromagnetic Heisenberg chains with alternating bond strength distributions. In the absence of randomness, bond alternation induces two quantum critical points between the $S=2$ Haldane phase, a partially dimerized phase and a fully dimerized phase, depending on the strength of dimerization. These three phases, called ($\sigma$,$4-\sigma$)=(2,2), (3,1) and (4,0) phases, are valence-bond solid (VBS) states characterized by $\sigma$ valence bonds forming across even links and $4-\sigma$ valence bonds on odd links. Here we study the effects of bond randomness on the ground states of the dimerized spin chain, calculating disorder-averaged twist order parameters and spin correlations. We classify the types of random VBS phases depending on strength of bond randomness $R$ and the dimerization $D$ using the twist order parameter, which has a negative/positive sign for a VBS phase with odd/even $\sigma$. Our results demonstrate the existence of a multicritical point in the intermediate disorder regime with finite dimerization, where (2,2), (3,1) and (4,0) phases meet. This multicritical point is at the junction of three phase boundaries in the $R$-$D$ plane: the (2,2)-(3,1) and (3,1)-(4,0) boundaries that extend to zero randomness, and the (2,2)-(4,0) phase boundary that connects another multicritical point in the undimerized limit. The undimerized multicritical point separates a gapless Haldane phase and an infinite-randomness critical line with the diverging dynamic critical exponent in the large $R$ limit at $D=0$. Furthermore, we identify the (3,1)-(4,0) phase boundary as an infinite-randomness critical line even at small $R$, and find the signature of infinite randomness at the (2,2)-(3,1) phase boundary only in the vicinity of the multicritical point.Comment: 13 pages, 14 figure