Quantum Dot in 2D Topological Insulator: The Two-channel Kondo Fixed Point

In this work, a quantum dot couples to two helical edge states of a 2D topological insulator through weak tunnelings is studied. We show that if the electron interactions on the edge states are repulsive, with Luttinger liquid parameter $K < 1$, the system flows to a stable two-channel fixed point at low temperatures. This is in contrast to the case of a quantum dot couples to two Luttinger liquid leads. In the latter case, a strong electron-electron repulsion is needed, with $K<1/2$, to reach the two-channel fixed point. This two-channel fixed point is described by a boundary Sine-Gordon Hamiltonian with a $K$ dependent boundary term. The impurity entropy at zero temperature is shown to be $\ln\sqrt{2K}$. The impurity specific heat is $C \propto T^{\frac{2}{K}-2}$ when $2/3 < K < 1$, and $C \propto T$ when $K<2/3$. We also show that the linear conductance across the two helical edges has non-trivial temperature dependence as a result of the renormalization group flow.Comment: 4+\epsilon page

X-ray analysis of the proper motion and pulsar wind nebula for PSR J1741-2054

We obtained six observations of PSR J1741-2054 using the $Chandra$ ACIS-S detector totaling $\sim$300 ks. By registering this new epoch of observations to an archival observation taken 3.2 years earlier using X-ray point sources in the field of view, we have measured the pulsar proper motion at $\mu =109 \pm 10 {\rm mas\ yr}^{-1}$ in a direction consistent with the symmetry axis of the observed H$\alpha$ nebula. We investigated the inferred past trajectory of the pulsar but find no compelling association with OB associations in which the progenitor may have originated. We confirm previous measurements of the pulsar spectrum as an absorbed power law with photon index $\Gamma$=2.68$\pm$0.04, plus a blackbody with an emission radius of (4.5$^{+3.2}_{-2.5})d_{0.38}$ km, for a DM-estimated distance of $0.38d_{0.38}$ kpc and a temperature of $61.7\pm3.0$ eV. Emission from the compact nebula is well described by an absorbed power law model with a photon index of $\Gamma$ = 1.67$\pm$0.06, while the diffuse emission seen as a trail extending northeast of the pulsar shows no evidence of synchrotron cooling. We also applied image deconvolution techniques to search for small-scale structures in the immediate vicinity of the pulsar, but found no conclusive evidence for such structures.Comment: 7 pages, 8 figures, 4 Tables; Accepted by Ap

Soluble Host Defense Lectins in Innate Immunity to Influenza Virus

Host defenses against viral infections depend on a complex interplay of innate (nonspecific) and adaptive (specific) components. In the early stages of infection, innate mechanisms represent the main line of host defense, acting to limit the spread of virus in host tissues prior to the induction of the adaptive immune response. Serum and lung fluids contain a range of lectins capable of recognizing and destroying influenza A viruses (IAV). Herein, we review the mechanisms by which soluble endogenous lectins mediate anti-IAV activity, including their role in modulating IAV-induced inflammation and disease and their potential as prophylactic and/or therapeutic treatments during severe IAV-induced disease

Deep Chandra Observations of the Pulsar Wind Nebula Created by PSR B0355+54

We report on Chandra X-ray Observatory (CXO) observations of the pulsar wind nebula (PWN) associated with PSR B0355+54 (eight observations with a 395 ks total exposure, performed over an 8 month period). We investigated the spatial and spectral properties of the emission coincident with the pulsar, compact nebula (CN), and extended tail. We find that the CN morphology can be interpreted in a way that suggests a small angle between the pulsar spin axis and our line-of-sight, as inferred from the radio data. On larger scales, emission from the 7' (2 pc) tail is clearly seen. We also found hints of two faint extensions nearly orthogonal to the direction of the pulsar's proper motion. The spectrum extracted at the pulsar position can be described with an absorbed power-law + blackbody model. The nonthermal component can be attributed to magnetospheric emission, while the thermal component can be attributed to emission from either a hot spot (e.g., a polar cap) or the entire neutron star surface. Surprisingly, the spectrum of the tail shows only a slight hint of cooling with increasing distance from the pulsar. This implies either a low magnetic field with fast flow speed, or particle re-acceleration within the tail. We estimate physical properties of the PWN and compare the morphologies of the CN and the extended tail with those of other bow shock PWNe observed with long CXO exposures.Comment: 11 pages, 8 figure

Discovering the Link between Investor Attention and Trade Volume in the Philippine Stock Exchange

Investors regard trade volume as a crucial technical indicator that can confirm trends, predict trend reversals, and determine liquidity (Westerhoff, 2006; Mahender et al., 2014). Trade volume is reported throughout the current trading day as often as once an hour; however, the reported hourly and end-of-the-day trade volumes are merely estimates. Actual and final trade volumes are reported the following day. Given the relative inconsistency of reported trade volumes and uncertainty of future trade volumes, investors miss the opportunity to reinforce their trading decisions through the trade volume indicator

Discovering the Relationship Between Investor Attention and Trade Volume in the Philippine Stock Exchange Using Google Search Analysis

This study investigates the relationship between daily Google search volume and trade volume in the Philippine Stock Exchange. This is completed by employing a sample consisting of listed stocks in the Philippine Stock Exchange from 2015 to 2019 and testing the veracity of three different keyword categories in proxying investor attention. The empirical results indicate that when using company names and stock tickers as Google search keywords, there is a strong positive relationship between Google search volume and trade volume. This implies that the more investors search for a stock’s company name or ticker, the more likely that there will be an increase in that stock’s trade volume the following day. Additionally, this study finds evidence that when using stock tickers as Google search keywords, aggregate investor sentiment can influence this relationship, such that it is more significant during periods of high consumer confidence. The findings support the notion that daily Google search volume can measure investor attention and potentially serve as a supplementary stock indicator for retail investors in the Philippine Stock Exchange

Foot Placement and Arm Position Affect the Five Times Sit-to-Stand Test Time of Individuals with Chronic Stroke

Objectives. To investigate the effect of two foot placements (normal or posterior placement) and three arm positions (hands on the thighs, arms crossed over chest, and augmented arm position with elbow extended) on the five times sit-to-stand (FTSTS) test times of individuals with chronic stroke. Design. Cross-sectional study. Setting. University-based rehabilitation clinic. Participants. A convenience sample of community-dwelling individuals with chronic stroke ( = 45). Methods. The times in completing the FTSTS with two foot placements and the three arm positions were recorded by stopwatch. Results. Posterior foot placement led to significantly shorter FTSTS times when compared with normal foot placement in all the 3 arm positions ( ≤ 0.001). In addition, hands on thigh position led to significantly longer FTSTS times than the augmented arm position ( = 0.014). Conclusion. Our results showed that foot placement and arm position could influence the FTSTS times of individuals with chronic stroke. Standardizing the foot placement and arm position in the test procedure is essential, if FTSTS test is intended to be used repeatedly on the same subject