Model-independent measurement of cosmic curvature with the latest H(z)H(z) and SNe Ia data: A comprehensive investigation

In the context of the discrepancies between the early and late universe, we emphasize the importance of independent measurements of the cosmic curvature in the late universe. We present an investigation of the model-independent measurement of the cosmic curvature parameter $\Omega_k$ in the late universe with the latest Hubble parameter $H(z)$ measurements and type Ia supernovae (SNe Ia) data. For that, we use two reconstruction methods, the Gaussian process (GP) and artificial neural network (ANN) methods, to achieve the distance construction from $H(z)$ data. Our analysis reveals that the GP method provides the most precise constraint on $\Omega_k$, with a constraint precision of $\xi(\Omega_k)=0.13$, surpassing recent estimations using similar methods. The GP method consistently indicates a preference for a flat universe at the 2$\sigma$ confidence level. Moreover, we find that the choice of reconstruction method influences the estimation of $\Omega_k$. The ANN reconstruction method exhibits higher sensitivity to the addition of BAO $H(z)$ data, resulting in comparable constraint precision to the GP method. A discrepancy exists between the best-fit values obtained by these two reconstruction methods, indicating their dependence on the reconstruction approach. However, we anticipate that with the improvement of sample size and precision of observational $H(z)$ data, the estimation of $\Omega_k$ using this approach will become more robust and reliable.Comment: 11 pages, 3 figures; accepted for publication in Physical Review

Anti-hypertensive effect of Gastrodia elata Bl leaf extract in rats

Purpose: To investigate the probable antihypertensive effects of Gastrodia elata Bl. extract (GEBE) in renovascular hypertensive rats as well as the mechanism involved in blood pressure reduction.Methods: The two-kidney one-clip (2K1C) Goldblatt model of renovascular hypertension was used in Wistar rats. The 2K1C group rats were treated with captopril (40 mg/kg/day), low-dose GEBE (150 mg/kg/day) and high-dose of GEBE (300 mg/kg/day) for 6 weeks by intragastric administration. Systolic (SBP) and diastolic blood pressure (DBP) were measured by the tail-cuff method. Urine creatinine and urea levels of the rats were measured by enzyme-linked immunosorbent assay (ELISA). Superoxide dismutase (SOD) and malondialdehyde (MDA) levels were also evaluated.Results: In the captopril- and GEBE-treated groups, blood pressure decreased progressively over the course of the 6-week treatment period compared with that of the untreated (control) rats (p < 0.01). High-dose GEBE also significantly increased plasma SOD activity but decreased plasma MDA concentration (p < 0.05). Renal function improved following captopril and GEBE (300 mg/kg/day) treatment (p < 0.01).Conclusion: The results suggest that GEBE probably exerts an antihypertensive effect by inhibiting endothelin (ET)-converting enzyme and via its antioxidant activity.Keywords: Antihypertensive, Gastrodia elata, Goldblatt renovascular hypertension, Endothelin-1, Hypertroph

The price Asian venture capitalists pay to work in Silicon Valley

They pay higher valuations due to their lower social status rather than social network disadvantages, write Jing Zhang, Poh-Kam Wong and Yuen-Ping H

Cloning, Identification, and Characterization of the rpoS-Like Sigma Factor rpoX from Vibrio alginolyticus

Vibrio alginolyticus ZJ-51 displays phase variation between opaque/rugose colonies (Op) and translucent/smooth colonies (Tr). These colony variants show great differences in biofilm formation and motility. In this study, a gene encoding for an rpoS-like sigma factor, rpoX, has been cloned and characterized. The absence of rpoX did not affect colony switching rate but did decrease biofilm formation in both the Op and the Tr variants. When challenged with hydrogen peroxide, the ΔrpoX in the Op background showed a slightly higher survival rate compared with the wild type, whereas survival was decreased in the Tr background. Deletion of rpoX in the Tr background resulted in a higher ability to resist ethanol challenges and to survive hyperosmolarity challenges, and in the Op background the opposite phenotype was observed. This indicates that the rpoX gene is involved in biofilm formation and stress response but the effects are controlled by colony phase variation in V. alginolyticus

IFRS Convergence and Stock Market Impact: Evidence from the 2007 China Reform

This study examines whether China’s adoption of new accounting standards in 2007 benefits shareholders by reducing information asymmetry in China’s stock market. Information asymmetry is measured by bid-ask spread, stock return volatility, and analyst forecast spread. Contrary to common perception and standard setter’s expectation, we find that information asymmetry has actually increased after the switch to the new CAS in 2007. Our results suggest that China’s recent convergence towards IFRS did not benefit shareholders, and that it was perceived negatively by market participants, which is consistent with earnings quality evidence from He et al. (2012)