A STUDY OF THE INFLUENCE FROM DIFFERENT RUNNING SLOPE ON THE ANGLES OF LIMB JOINTS

This study focuses on an analysis and comparison of the hip, knee, and ankle joint angle changes and differences during the stance and swing phase of the running gait cycle while running on the same uphill or downhill gradient as well as the lower joint angle changes while running on different uphill or downhill inclines or on level ground. This study should also provide insight into whether or not there is a significant difference between the lower joint angle patterns while running on slopes of different steepness, which in turn can serve as a reference for runners and coaches for uphill or downhill running training or workout exercises. For this study we employed a high-speed camera, which allows us to capture the running motion cycles of the sagittal plane of test subjects while running on different uphill or downhill gradients. Motion analysis software was employed for data compilation, while a comparative analysis was conducted by utilizing statistical software. After extensive discussions and analysis, we reached the following conclusions: 1. Slope gradient changes have a significant impact on hip joint angles during the stance phase. The steeper the incline is, the greater is the difference between the hip joint angles. 2. Slope gradient changes have a significant effect on joint angle changes during the swing phase. The steeper the uphill gradient, the smaller are the hip, knee, and ankle joint angles, while steeper downhill gradients lead to larger hip and knee joint angles. 3. A comparison of the changes of all joint angles during uphill, downhill, and level ground running reveals that angle changes during uphill running are greater than during downhill running. It can be inferred that this phenomenon is caused by the fact that the number of muscle groups involved in uphill running is larger than in downhill running

Does unemployment have asymmetric effects on suicide rates? Evidence from the United States: 1928–2013

This study applied the recently developed asymmetric causality test and asymmetric generalised impulse-response method to demonstrate the dynamic relationship between unemployment and suicide rates in the U.S. over the period of 1928–2013. The results suggest that there exist asymmetric effects of unemployment on suicide rates. An economic recession (in terms of an increase in unemployment rate) is more likely to increase the suicide rate among an old age group (55–64 years old) than among other age groups, while an economic expansion (in terms of a decrease in unemployment rate) is more likely to reduce the suicide rate of young (15–24 and 25–34 years old) and middle age groups (35–44 and 45– 54 years old) than their counterpart. Therefore, policy implications generated from our results include the following: that intervention to prevent suicidal behaviour should be directed more towards the older age group during economic recession and that we may expect that an economic expansion may not result in a great reduction of suicide rates for the old age (55–64 years) group

Probing Transverse Momentum Broadening via Dihadron and Hadron-jet Angular Correlations in Relativistic Heavy-ion Collisions

Dijet, dihadron, hadron-jet angular correlations have been reckoned as important probes of the transverse momentum broadening effects in relativistic nuclear collisions. When a pair of high-energy jets created in hard collisions traverse the quark-gluon plasma produced in heavy-ion collisions, they become de-correlated due to the vacuum soft gluon radiation associated with the Sudakov logarithms and the medium-induced transverse momentum broadening. For the first time, we employ the systematical resummation formalism and establish a baseline calculation to describe the dihadron and hadron-jet angular correlation data in $pp$ and peripheral $AA$ collisions where the medium effect is negligible. We demonstrate that the medium-induced broadening $\langle p_\perp^2\rangle$ and the so-called jet quenching parameter $\hat q$ can be extracted from the angular de-correlations observed in $AA$ collisions. A global $\chi^2$ analysis of dihadron and hadron-jet angular correlation data renders the best fit $\langle p_\perp^2 \rangle \sim 13~\textrm{GeV}^2$ for a quark jet at RHIC top energy. Further experimental and theoretical efforts along the direction of this work shall significantly advance the quantitative understanding of transverse momentum broadening and help us acquire unprecedented knowledge of jet quenching parameter in relativistic heavy-ion collisions.Comment: 6 pages, 3 figure

Dimensionless ratios: characteristics of quantum liquids and their phase transitions

Dimensionless ratios of physical properties can characterize low-temperature phases in a wide variety of materials. As such, the Wilson ratio (WR), the Kadowaki-Woods ratio and the Wiedemann\--Franz law capture essential features of Fermi liquids in metals, heavy fermions, etc. Here we prove that the phases of many-body interacting multi-component quantum liquids in one dimension (1D) can be described by WRs based on the compressibility, susceptibility and specific heat associated with each component. These WRs arise due to additivity rules within subsystems reminiscent of the rules for multi-resistor networks in series and parallel --- a novel and useful characteristic of multi-component Tomonaga-Luttinger liquids (TLL) independent of microscopic details of the systems. Using experimentally realised multi-species cold atomic gases as examples, we prove that the Wilson ratios uniquely identify phases of TLL, while providing universal scaling relations at the boundaries between phases. Their values within a phase are solely determined by the stiffnesses and sound velocities of subsystems and identify the internal degrees of freedom of said phase such as its spin-degeneracy. This finding can be directly applied to a wide range of 1D many-body systems and reveals deep physical insights into recent experimental measurements of the universal thermodynamics in ultracold atoms and spins.Comment: 12 pages (main paper), (6 figures