Studies of Isolated and Non-isolated Photospheric Bright Points in an Active Region Observed by the New Vacuum Solar Telescope

Properties of photospheric bright points (BPs) near an active region have been studied in TiO λ 7058 Å images observed by the New Vacuum Solar Telescope of the Yunnan Observatories. We developed a novel recognition method that was used to identify and track 2010 BPs. The observed evolving BPs are classified into isolated (individual) and non-isolated (where multiple BPs are observed to display splitting and merging behaviors) sets. About 35.1% of BPs are non-isolated. For both isolated and non-isolated BPs, the brightness varies from 0.8 to 1.3 times the average background intensity and follows a Gaussian distribution. The lifetimes of BPs follow a log-normal distribution, with characteristic lifetimes of (267 ± 140) s and (421 ± 255) s, respectively. Their size also follows log-normal distribution, with an average size of about (2.15 ± 0.74) × 104 km2 and (3.00 ± 1.31) × 104 km2 for area, and (163 ± 27) km and (191 ± 40) km for diameter, respectively. Our results indicate that regions with strong background magnetic field have higher BP number density and higher BP area coverage than regions with weak background field. Apparently, the brightness/size of BPs does not depend on the background field. Lifetimes in regions with strong background magnetic field are shorter than those in regions with weak background field, on average

Environmental behavior of linear alkylbenzene sulfonate (LAS) in aquatic ecosystem.

LAS degradation rate in Donghu Lake water under aerobic was much faster than under anaerobic condition. The half life of LAS in aerobic and anaerobic environment was 3.2 days and 57 days, respectively. The degradation rate at 25-27°C was approximately 20 times higher than that at 1.5-3.5 °C. In a laboratory model aquatic ecosystem, two stages of bioconcentration in fish, daphnia and snail were observed. The first stage, on second day exposure, resulted from accumulation of intact LAS, and the second stage, on 16th day exposure, was due to metabolites. The bioconcentration factor (BCF) of LAS was extremely low in the muscle of hybrid carp (0.64), but rather high (2485) in the gall bladder