Long-Run Purchasing Power Parity with Asymmetric Adjustment: Evidence from Mainland China and Taiwan

This study applies threshold cointegration test advanced by Enders and Siklos (2001) to investigate the properties of asymmetric adjustment in long-run purchasing power parity (PPP) for both Mainland China and Taiwan during the January 1986 to October 2009 period. Although there is evidence of long-run PPP for both Mainland China and Taiwan, the adjustment mechanism is asymmetric. These results have important policy implications for both Mainland China and Taiwan under study.threshold cointegration test; Purchasing Power Parity; asymmetric adjustment; Mainland China; Taiwan

Characterizing Intermittency of 4-Hz Quasi-periodic Oscillation in XTE J1550-564 using Hilbert-Huang Transform

We present the time-frequency analysis results based on the Hilbert-Huang transform (HHT) for the evolution of a 4-Hz low-frequency quasi-periodic oscillation (LFQPO) around the black hole X-ray binary XTE J1550-564. The origin of LFQPOs is still debated. To understand the cause of the peak broadening, we utilized a recently developed time-frequency analysis, HHT, for tracking the evolution of the 4-Hz LFQPO from XTE J1550 564. By adaptively decomposing the ~4-Hz oscillatory component from the light curve and acquiring its instantaneous frequency, the Hilbert spectrum illustrates that the LFQPO is composed of a series of intermittent oscillations appearing occasionally between 3 Hz and 5 Hz. We further characterized this intermittency by computing the confidence limits of the instantaneous amplitudes of the intermittent oscillations, and constructed both the distributions of the QPO's high and low amplitude durations, which are the time intervals with and without significant ~4-Hz oscillations, respectively. The mean high amplitude duration is 1.45 s and 90% of the oscillation segments have lifetimes below 3.1 s. The mean low amplitude duration is 0.42 s and 90% of these segments are shorter than 0.73 s. In addition, these intermittent oscillations exhibit a correlation between the oscillation's rms amplitude and mean count rate. This correlation could be analogous to the linear rms-flux relation found in the 4-Hz LFQPO through Fourier analysis. We conclude that the LFQPO peak in the power spectrum is broadened owing to intermittent oscillations with varying frequencies, which could be explained by using the Lense-Thirring precession model.Comment: 27 pages, 9 figures, accepted for publication in The Astrophysical Journa

Long-term Periodicities of Cataclysmic Variables with Synoptic Surveys

A systematic study on the long-term periodicities of known Galactic cataclysmic variables (CVs) was conducted. Among 1580 known CVs, 344 sources were matched and extracted from the Palomar Transient Factory (PTF) data repository. The PTF light curves were combined with the Catalina Real-Time Transient Survey (CRTS) light curves and analyzed. Ten targets were found to exhibit long-term periodic variability, which is not frequently observed in the CV systems. These long-term variations are possibly caused by various mechanisms, such as the precession of the accretion disk, hierarchical triple star system, magnetic field change of the companion star, and other possible mechanisms. We discuss the possible mechanisms in this study. If the long-term period is less than several tens of days, the disk precession period scenario is favored. However, the hierarchical triple star system or the variations in magnetic field strengths are most likely the predominant mechanisms for longer periods.Comment: 33 pages, 9 figures (manuscript form), Accepted for publication in PAS

Susceptibility of Human Embryonic Stem Cell-Derived Neural Cells to Japanese Encephalitis Virus Infection

Pluripotent human embryonic stem cells (hESCs) can be efficiently directed to become immature neuroepithelial precursor cells (NPCs) and functional mature neural cells, including neurotransmitter-secreting neurons and glial cells. Investigating the susceptibility of these hESCs-derived neural cells to neurotrophic viruses, such as Japanese encephalitis virus (JEV), provides insight into the viral cell tropism in the infected human brain. We demonstrate that hESC-derived NPCs are highly vulnerable to JEV infection at a low multiplicity of infection (MOI). In addition, glial fibrillary acid protein (GFAP)-expressing glial cells are also susceptible to JEV infection. In contrast, only a few mature neurons were infected at MOI 10 or higher on the third day post-infection. In addition, functional neurotransmitter-secreting neurons are also resistant to JEV infection at high MOI. Moreover, we discover that vimentin intermediate filament, reported as a putative neurovirulent JEV receptor, is highly expressed in NPCs and glial cells, but not mature neurons. These results indicate that the expression of vimentin in neural cells correlates to the cell tropism of JEV. Finally, we further demonstrate that membranous vimentin is necessary for the susceptibility of hESC-derived NPCs to JEV infection

Smoking, Habitual Tea Drinking and Metabolic Syndrome in Elderly Men Living in Rural Community: The Tianliao Old People (TOP) Study 02

The literature shows an inconsistent relationship between lifestyle behaviors and metabolic syndrome (MetS), especially in the elderly. We designed this study to investigate the interrelationships among cigarette smoking, tea drinking and MetS, and to verify the factors associated with MetS in elderly males dwelling in rural community. In July 2010, with a whole community sampling method, 414 male subjects aged over 65 dwelling in Tianliao township were randomly sampled. The response rate was 60.8%. Each subject completed the structured questionnaires including sociodemographic characteristics, habitual behaviors (including cigarette smoking and tea drinking habits) and medical history. After an overnight fast, the laboratory and anthropometric data were obtained. MetS was confirmed according to the criteria defined by the modified NCEP ATP III for the male Chinese population. Subjects were split into either non-MetS or MetS groups for further analysis. Of the 361 subjects with complete data, 132 (36.6%) elderly men were classified as having MetS. Using binary logistic regression, body mass index, serum uric acid, high sensitivity C-reactive protein, HOMA index, current smokers (OR = 2.72, 95%CI: 1.03 ∼ 7.19), total smoking amount > = 30 (OR = 2.78, 95%CI: 1.31 ∼ 5.90) and more than 20 cigarettes daily (OR = 2.54, 95%CI: 1.24 ∼ 5.18) were positively associated with MetS. Current un- or partial fermented tea drinker (OR = 0.42, 95%CI: 0.22 ∼ 0.84), tea drinking habit for 1–9 years (OR = 0.36, 95%CI: 0.15 ∼ 0.90) and more than 240cc daily (OR = 0.35, 95%CI: 0.17 ∼ 0.72) were negatively associated with MetS. In conclusion, this study suggests that smoking habit was positively associated with MetS, but tea drinking habit was negatively associated with MetS in elderly men dwelling in rural community