The 2011 oil spill in the Bohai Sea was the largest spill event in China. Nine sediment cores were taken near the spill site and environmental factors including Polycyclic Aromatic Hydrocarbon (PAHs), oils, sulfides, organic carbon were measured 6 months later. Benthic foraminifera were separated into >150 μm (large) and 63-150 μm (small) size fractions for 2-cm depth interval of each sediment core. Statistical analyses suggested that the species composition of living foraminifera was impacted by oils, PAHs and sulfides. Large foraminifera were more sensitive to the oils than the small. Abnormal specimens were positively correlated with oils or PAHs. Small forms, however, tended to have high reproduction and mortality. Pollution-resistant and opportunistic taxa were identified to calculate a Foraminiferal Index of Environmental Impacts (FIEI). The FIEI increased from low to high oil-polluted station and from deep layer to surface sediment reflects the impact of oil pollution in this area.
The Multiple Displacement Amplification (MDA) protocol is reported to introduce different artifacts into DNA samples with impurities. In this study, we report an artifactual effect of MDA with sediment DNA samples from a deep-sea brine basin in the Red Sea. In the metagenomes, we showed the presence of abundant artifactual 454 pyrosequencing reads over sizes of 50 to 220 bp. Gene fragments translocated from neighboring gene regions were identified in these reads. Occasionally, the translocation occurred between the gene fragments from different species. Reads containing these gene fragments could form a strong stem-loop structure. More than 60% of the artifactual reads could fit the structural models. MDA amplification is probably responsible for the massive generation of the artifactual reads with the secondary structure in the metagenomes. Possible sources of the translocations and structures are discussed.
Recent occurrence and distribution of 16 priority polycyclic aromatic hydrocarbons (PAHs) proposed by USEPA in the northern Yellow River Delta (YRD) were studied based on the analytical data of 20 surface soil samples. The concentrations of 16 PAHs varied from 27.5 to 129 ng g-1 (dry weight). A clear tendency was observed that the total concentration of 16 PAHs is getting lower from west to the east in this area. The eco-toxicological risk assessment showed that this area is at low ecological risk region, which might not exert significant potential damage to the organisms. Four to six ring PAHs were predominantly from the coal and wood combustions in the whole area.
Aiming at uncertainty of process plans in the process decision making, the paper introduced a method based on ant colony optimization (ACO) to find out the set of optimal solutions for multi-objective machine tool selection. The Analytic Hierarchy Process (AHP) was applied to simplify process decision making plans, and the structural diagram of AHP was made up according to the different demands of manufacturing engineer. By means of the examples the different elements to different manufacturing processes are comprehensive evaluated, and the most splendid process scheme is evaluated, meanwhile the feasibility of the proposed method applying process decision making is verified.
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