Search

Environmental factors are generally considered to be important factors affecting the release process of phosphorus (P) in sediments. However, little is known about the effect of temperature increased at first and then decreased with the season change on the P flux rate and flux amount at the sediment–water interface in the steppe wetlands. The effects of the temperature variation on P flux at the sediment–water interface in the steppe wetlands during the vegetation growing season under simulated wetland habitat were studied. The results showed that the release of P from sediments to overlying water was greatly affected by temperature changes. When the temperature rose, P was released from the sediment into the overlying water, while P was precipitated from the water into the sediment with the temperature dropped. During simulation period, the total P in water flux rates between sediment and overlying water (FP) was ranged from − 4.51 to 4.99 mg·m−2·day−1, while the dissolved reactive P in water flux rates between sediment and overlying water (FDP) was changed from − 5.37 to 5.14 mg·m−2·day−1. The FP and FDP were negatively correlated with the content of total P in water (WTP), dissolved reactive P in water (WDRP), pH of sediment (pH), and microbial biomass P (MBP), but increased with temperature (T), aluminum phosphate (Al.P), and occluded phosphate (Oc.P). The P flux rates were affected by temperature variation both directly and indirectly; the mechanism of how temperature influenced the fate of P in the wetland is still not clear. Therefore, the physicochemical properties and kinetic, thermodynamic, and microbiology characteristics should be combined together to clarify the mechanism in future research. [ABSTRACT FROM AUTHOR]

Traffic congestion and smog are hot topics in recent years. This study analyzes the impacts of road traffic characteristic parameters on urban air quality quantitatively based on aerosol optical thickness (AOD) and geographical weighted regression (GWR) models, including the road network density, road area occupancy, intersection number, and bus network density as main factors. There are some major research findings. Firstly, there exists a strong positive correlation between the peak congestion delay index (PCDI) and air quality, the correlation has R2 values of up to 0.4962 (R 0.70). Secondly, GWR refines the local spatial changes in the AOD and the road parameters, and the correlation R2 based GWR model all above 0.6. The correlation between AOD and the road area occupancy was the highest, and the correlations with the bus network density and the intersections number were higher than that with the road network density. Thus, bus route planning, bus emission reduction, road network planning, and signal timing (at intersections) have a greater impact on air quality than other policy, especially in areas with traffic jams. The results of this study could provide theoretical support for traffic planning and traffic control, and is promising in practice. [ABSTRACT FROM AUTHOR]

This article examines the evolution of national research policy in China over the past three decades and its recent shift in emphasis from 'import' to 'import-export' oriented internationalization. Based on a policy review and interviews with three groups of academics-six journal editors in the humanities and social sciences, two directors from top-tier Chinese university Departments of Scientific Research Administration, and six scholars from different disciplines-the article investigates the impact of national research policy and its recent shift towards 'going out' on scholarly publishing in China. The paper reveals Chinese academia's quandary with regard to internationalization and discusses the link with larger debates about uni- and bi-directionality in academic knowledge exchange. [ABSTRACT FROM AUTHOR]