Effect of Particle Spin on Trajectory Deflection and Gravitational Lensing

Spin of a test particle is a fundamental property that can affect its motion in a gravitational field. In this work we consider the effect of particle spin on its deflection angle and gravitational lensing in the equatorial plane of arbitrary stationary and axisymmetric spacetimes. To do this we developed a perturbative method that can be applied to spinning signals with arbitrary asymptotic velocity and takes into account the finite distance effect of the source and the observer. The deflection angle $\Delta\varphi$ and total travel time $\Delta t$ are expressed as (quasi-)power series whose coefficients are polynomials of the asymptotic expansion coefficients of the metric functions. It is found that when the spin and orbital angular momenta are parallel (or antiparallel), the deflection angle is decreased (or increased). Apparent angles $\theta$ of the images in gravitational lensing and their time delays are also solved. In Kerr spacetime, spin affects the apparent angle $\theta_K$ in a way similar to its effect on $\Delta\varphi_K$. The time delay between signals with opposite spins is found to be proportional to the signal spin at leading order. These time delays might be used to constrain the spin to mass ratio of neutrinos.Comment: 33 pages, 7 figures, to match the published versio

On Secrecy Performance for Energy-Harvesting Multi-Antenna Relaying Networks with a Dual-Use Source

This paper studies the secrecy performance of an energy-harvesting relaying system in the presence of a dual-use source node and an eavesdropper. Specifically, the source has dual roles in the dual-hop communication: 1) to transmit confidential information in the first hop; 2) to generate jamming signal to interfere the eavesdropper in the second hop. Moreover, the multi-antenna relay deploys a power-splitting harvesting scheme to coordinate the information receiving and energy harvesting, and adopts maximal ratio combining technique to process the multiple copies of signals. Considering decode-and-forward protocol and transmit antenna selection scheme, we derive an analytical expression for secrecy outage probability, and perform Monte Carlo simulation to validate the analysis. Analytical results show that the SOP performance with the dual-use source node can be effectively improved when the relay-destination channel does not have absolute advantage over the relay-eavesdropper channel

Customer Satisfaction Evaluation on Tokopedia E-Commerce Platform under Belt and Belt and Road Initiative

This research intended to study the Customer Satisfaction Evaluation on Tokopedia E-Commerce Platform under Belt and Road Initiative where this is based on the dimensions of performance, features, reliability, conformance, durability, serviceability, aesthetics, and perceived quality. The method used in this research is observation, questionnaires, and literature. While for the data analysis technique used is Multiple Linear Regression Analysis. The author takes an object of research in the year 2021 with a total sample of 358 respondents. Data collection technique that is adopted is convenience sampling method. The author distributed the questionnaires with 39 questions using dimensional performance, feature, reliability, conformance, durability, serviceability, aesthetics, and perceived quality. Belt and Road Initiative (BRI) through Indonesia’s E-Commerce Platform Tokopedia, Performance (X1), Reliability (X2), Feature (X3), Conformance (X4), Durability (X5), Serviceability (X6), Aesthetics (X7), Perceived Quality (X8) simultaneously affects the dependent variable Customer Satisfaction (Y). The percentage of the influence of the independent variables on the dependent variable is shown by the coefficient of simultaneous determination (R2). In this study, the magnitude of the R Square is 0.979. This means that the rise and fall of the dependent variable, namely performance (Y), is influenced by the independent variables, namely Performance (X1), Reliability (X2), Feature (X3), Conformance (X4), Durability (X5), Serviceability (X6), Aesthetics (X7), Perceived Quality (X8) by 97.9% while the remaining 2.1 percent is influenced by other variables outside of this study. There is a positive significant influence of Belt and Road Initiative (BRI) through the Product Quality towards the Customer Satisfaction Evaluation of Tokopedia Indonesia. Keywords: Belt and Road (BRI), Customer Satisfaction, Product Quality, Tokopedia DOI: 10.7176/JESD/12-6-02 Publication date:March 31st 202

Comparison of the Rehabilitation Effects of Taichi Exercise and Functional Exercise on Scapulohumeral Periarthritis

Purpose: To investigate and compare the rehabilitation effects of Taichi exercise and functional exercise on scapulohumeral periarthritis. Method: Eighty patients with scapulohumeral periarthritis from a community in Jingzhou, Hubei, China, were randomly selected from January to June 2016. They were randomly divided into the experimental group and the control group. On the basis of routine treatment and nursing, the experimental group (40 patients) adopted the Taichi exercise treatment while the control group (40 patients) adopted the functional exercise treatment. In the end, the shoulder joint pain degree changes, and the improvement of shoulder joint movements and the myoelectricity and myodynamia on the surfaces of the shoulder muscle group of the two groups were tested and measured. Result: The scoring difference of shoulder joint pain between the experimental group and the control group is significant, which is of statistical significance (P < 0.05). Before the treatment, the difference of shoulder joint movement between the two groups isn't significant, with no statistical significance, but after the treatment, the difference is significant, which is of statistical significance (P < 0.05). The myodynamia difference between the two groups after the treatment is significant, which is of statistical significance (P < 0.05). The therapy efficiency of the experimental group is higher than that of the control group and the difference is significant, which is of statistical significance (P < 0.05). Conclusion: On the basis of routine physical treatment, adopting Taichi exercise can increase the therapy efficiency on the patients with scapulohumeral periarthritis, can improve the blood supply and inflammation on the shoulder and improve patient's life quality