The toxicity of nano-materials has received increasing attention in recent years.Nevertheless,relatively few studies have focused on their oceanic distributions and toxicities.In this study,we assessed nano-ZnO toxicity in marine organisms using the yellowstriped goby(Mugilogobius chulae).The relative differences in nano-ZnO dissolution and dispersal in seawater and fresh water were also investigated.The effects of nano-ZnO on embryonic development,deformity,hatching,mortality,and histopathology were analyzed.In addition,the effects of the Zn~(2+) concentration on M.chulae hatching and mortality were compared.The results showed that nano-ZnO had higher solubility in seawater than in fresh water.Nano-ZnO significantly inhibited hatching.By the fifth day of exposure,the LC_(50) of nano-ZnO was 45.40 mg/L,and the mortality rate spiked.Hatching inhibition and lethality were dose-dependent over a range of1–25 mg/L nano-ZnO.Zn~(2+) inhibited hatching and increased lethality,but its effects were weaker than those of nano-ZnO at the same concentrations.Nano-ZnO also induced spinal bending,oedema,hypoplasia,and other deformities in M.chulae embryos and larvae.Histopathology revealed vacuolar degeneration,hepatocyte and enterocyte enlargement,and morphological abnormalities of the vertebrae.Therefore,nano-ZnO caused malformations in M.chulae by affecting embryonic growth and development.We conclude that nano-ZnO toxicity in seawater was significantly positively correlated with the associated Zn~(2+) concentration and sedimentary behaviour.The toxicity of nano-ZnO was cumulative and showed a critical point,beyond which embryonic and developmental toxicity in marine fish was observed. 相似文献
The role of social context (e.g., leadership, team climate, and organizational support) in shaping employee proactive behavior has received considerable attention and has been investigated across multiple forms of proactive behavior. However, the research has not been well integrated. In this review, we adopt a multilevel approach to synthesize what is known about how social context factors influence employees' proactive behavior, as well as what mechanisms underpin these effects. Our analyses show that leader‐, team‐, and organization‐related social context factors mainly influence employee proactivity through shaping “reason to,” “can do,” and “energized to” states (i.e., proactive motivational states) via individual‐, team‐, and cross‐level processes. That has been most frequently investigated is the effect of the discretionary social context, particularly leadership, on proactive behavior. We also review the interaction effects between social context factors and other factors on employee proactive behavior and found inconsistent support for the motivational‐fit perspective that stimuli with the same directions enhance each other's effect. We offer a research agenda to advance theoretical insights on this important topic. 相似文献
Long-term use of chlorpyrifos poses a potential threat to the environment that cannot be ignored, yet little is known about the succession of substrate microbial communities in constructed wetlands(CWs) under chlorpyrifos stress. Six pilot-scale CW systems receiving artificial wastewater containing 1 mg/L chlorpyrifos were established to investigate the effects of chlorpyrifos and wetland vegetation on the microbial metabolism pattern of carbon sources and community structure, using BIOLOG and denaturing gradient gel electrophoresis(DGGE) approaches. Based on our samples, BIOLOG showed that Shannon diversity(HV) and richness(S) values distinctly increased after 30 days when chlorpyrifos was added. At the same time, differences between the vegetated and the non-vegetated systems disappeared. DGGE profiles indicated that H Vand S had no significant differences among four different treatments. The effect of chlorpyrifos on the microbial community was mainly reflected at the physiological level. Principal component analysis(PCA) of both BIOLOG and DGGE showed that added chlorpyrifos made a difference on test results.Meanwhile, there was no difference between the vegetation and no-vegetation treatments after addition of chlorpyrifos at the physiological level. Moreover, the vegetation had no significant effect on the microbial community at the genetic level. Comparisons were made between bacteria in this experiment and other known chlorpyrifos-degrading bacteria. The potential chlorpyrifos-degrading ability of bacteria in situ may be considerable. 相似文献
In this work, a one-year observation focusing on high time resolution characteristics of components in fine particles was conducted at an urban site in Shanghai. Contributions of different components on visibility impairment were also studied. Our research indicates that the major components of PM2.5 in Shanghai are water-soluble inorganic ions and carbonaceous aerosol, accounting for about 60% and 30% respectively. Higher concentrations of sulfate (SO42−) and organic carbon (OC) in PM2.5 occurred in fall and summer, while higher concentrations of nitrate (NO3−) were observed in winter and spring. The mass concentrations of Cl− and K+ were higher in winter. Moreover, NO3− increased significantly during PM2.5 pollution episodes. The high values observed for the sulfate oxidizing rate (SOR), nitrate oxidizing rate (NOR) and secondary organic carbon (SOC) in OC indicate that photochemical reactions were quite active in Shanghai. The IMPROVE (Interagency Monitoring of Protected Visual Environments) formula was used in this study to investigate the contributions of individual PM2.5 chemical components to the light extinction efficient in Shanghai. Both NH4NO3 and (NH4)2SO4 had close relationships with visibility impairment in Shanghai. Our results show that the reduction of anthropogenic SO2, NOx and NH3 would have a significant effect on the improvement of air quality and visibility in Shanghai. 相似文献
Objective: With increasing traffic volume and urban development, increasing numbers of underground tunnels have been constructed to relieve conflict between strained land and heavy traffic. However, as more long tunnels are constructed, tunnel traffic safety is becoming increasingly serious. Thus, it is necessary to acquire their implications and impacts. This study examined 4,539 traffic accidents that have occurred in 14 Shanghai river-crossing tunnels for the period 2011–2012 and analyze the correlation between potential factors and accident injury severity.
Methods: An ordered logit model was developed to examine the correlation between potential factors and accident injury severity.
Results: Results show that increased injury severity is associated with male drivers, drivers aged 65 years or older, accident time from midnight to dawn, weekends, wet road surface, goods vehicles, 3 or more vehicles, 4 or more lanes, middle speed limits (50–79 km/h), zone 3, extra-long tunnels (over 3,000 m), and maximum longitudinal gradient.
Conclusions: This article aims to provide useful information for engineers to develop interventions and countermeasures to improve tunnel safety in China. 相似文献
The article presents the distribution and enrichment of acid-leachable heavy metals (ALHMs) Cu, Zn, Pb, Cr, Mn, and Fe in the intertidal sediments collected from Quanzhou Bay, southeast coast of China. The contents of ALHMs along with sediment texture, total organic carbon, S2???, and CaCO3 in surface sediments were analyzed to identify the input of heavy metals from various sources. The enrichment of ALHMs in the sediments is mainly attributed to the intense industrial activities around Quanzhou Bay and to the serried activities of intertidal breed aquatics along the seacoast. The results also illustrate the association between the ALHMs with the finer fractions, organic matter, and Fe oxyhydroxides in the sediments. The above results were very supported by the multivariate statistical analyses, including correlation, principal component analysis, and hierarchical clustering analysis. Comparative results of ALHMs in the intertidal sediments from Quanzhou Bay with those in other domestic bays and estuaries indicate that the study area has been enriched with heavy metals, especially with Zn, Cu, and Pb, during the past few decades. The results of the present study suggest that the authorities should pay attention to the current status and take some measures to control the heavy metal pollution in the study area. 相似文献