我国防灾减灾法的性质与地位问题初探

从属性上讲,我国防灾减灾法不只是行政管理法,而应是社会安全与可持续发展保障法;我国防灾减灾法不纯粹是公法,而应是公法与私法兼备的综合法。从地位来看,我国防灾减灾法是一个新兴的独立的法律部门。在中国特色社会主义法律体系中,我国《防灾减灾法》是一部重要的新兴的基本法与综合法。     

Cadmium contamination in Tianjin agricultural soils and sediments: relative importance of atmospheric deposition from coal combustion

Cadmium (Cd) in coal, fly ash, slag, atmospheric deposition, soils and sediments collected from Tianjin, northern China, were measured to provide baseline information and determine possible Cd sources and potential risk. The concentrations of Cd in coal, fly ash and atmospheric deposition were much higher than the soil background values. Fallout from coal-fired thermal power plants, heating boilers and industrial furnaces has increased the Cd concentration in soils and sediments in Tianjin. The concentrations of Cd in soils of suburban areas were significantly higher than in rural areas, suggesting that coal burning in Tianjin may have an important impact on the local physical environment. Cd from coal combustion is readily mobilized in soils. It is soluble and can form aqueous complexes and permeate river sediments. The high proportion of mobile Cd affects the migration of Cd in soils and sediments, which may pose an environmental threat in Tianjin due to the exposure to Cd and Cd compounds via the food chain. This study may provide a window for understanding and tracing sources of Cd in the local environment and the risk associated with Cd bioaccessibility.     

Chelator-induced bioextraction of heavy metals from artificially contaminated soil by mushroom (Coprinus comatus)

This study investigated the potential use of chelator-induced bioextraction of heavy metals from soil by Coprinus comatus in a pot experiment. Two production waves of the mushroom were obtained to determine biomass and metal concentration. The application of ethylenediaminetetraacetic acid (EDTA) or nitrilotriacetate (NTA) slightly inhibited the growth of C. comatus, but significantly enhanced the accumulation of heavy metals in fruiting bodies compared with the control. The highest concentrations of Pb, Cu and Cd reached 900.60, 783.61 and 23.64 mg·kg^?1 in a single pot, respectively. However, application of citric acid (CA) had no effect on metal uptake. Moreover, chelators applied to soil after fructification increased the dry biomass and metal concentration in fruiting bodies compared with those applied before sowing mycelia. EDTA was more efficient for inducing metal uptake by C. comatus than NTA or CA, and split applications of EDTA after fructification resulted in the highest total metal uptake by mushroom, i.e. 19.08±2.84, 17.57±0.69 and 0.55±0.06 mg for Pb, Cu and Cd, respectively, which were 130, 12 and 5 times values obtained with the control. Interestingly, many mushrooms turned blue after soil had been treated with chelator, indicating that these mushrooms are rich in Cu.     

Despotic, high-impact species and the subcontinental scale control of avian assemblage structure

Some species have disproportionate influence on assemblage structure, given their numbers or biomass. Most examples of such "strong interactors" come from small-scale experiments or from observations of the effects of invasive species. There is evidence that entire avian assemblages in open woodlands can be influenced strongly by individual species over very large areas in eastern Australia, with small-bodied species (< 50 g) being adversely affected. We used data from repeated surveys in 371 sites in seven districts across a region from Victoria to Queensland (> 2000 km). A series of linked Bayesian models was used to identify large-bodied (> or = 50 g) bird species that were associated with changes in occurrence and abundance of small-bodied species. One native species, the Noisy Miner (Manorina melanocephala; family Meliphagidae), was objectively identified as the sole large-bodied species having similar detrimental effects in all districts, depressing occurrence of 57 of 71 small-bodied species. Adverse effects on abundances of small-bodied species were profound when the Noisy Miner occurred with mean site abundances > or = 1.6 birds/2 ha. The Noisy Miner may be the first species to have been shown to influence whole-of-avifauna assemblage structure through despotic aggressiveness over subcontinental scales. These substantial shifts in occurrence rates and abundances of small-bodied species flow on to alter species abundance distributions of entire assemblages over much of eastern Australia.     

Is the Great Barracuda (<Emphasis Type="Italic">Sphyraena barracuda</Emphasis>) a reef fish or a pelagic fish? The phylogeographic perspective

Current taxonomy indicates a single global species of the Great Barracuda (Sphyraena barracuda) despite differences in color and behavior between Atlantic and Pacific forms. To investigate these differences and qualify the dispersal characteristics of this unique coastal–pelagic teleost (bony fish), we conducted a global phylogeographic survey of 246 specimens from thirteen sampling locations using a 629-base pair fragment of mtDNA cytochrome b. Data indicate high overall gene flow in the Indo-Pacific over large distances (>16,500 km) bridging several biogeographic barriers. The West Atlantic population contains an mtDNA lineage that is divergent from the Indo-Pacific (d = 1.9%), while the East Atlantic (N = 23) has two mutations (d = 0.6%) apart from the Indo-Pacific. While we cannot rule out distinct evolutionary partitions among ocean basins based on behavior, coloration, and near-monophyly between Atlantic and Indo-Pacific subpopulations, more investigation is required before taxonomic status is revised. Overall, the pattern of high global dispersal and connectivity in S. barracuda more closely resembles those reported for large oceanic predators than reef-associated teleosts.     

氧化改性对活性炭吸附二苯并噻吩的影响

采用硝酸作为氧化剂,对树脂基球形活性炭(RCS)表面进行氧化改性,分别考察了氧化时间、氧化温度及硝酸浓度对改性RCS吸附脱除油品中二苯并噻吩(DBT)的性能影响.通过N2吸附、Boehm滴定和热重分析等手段对改性前后的RCS进行表征.实验结果表明:较为经济有效的改性工艺条件为硝酸浓度10 mol/L,氧化温度60℃,氧化时间3h;改性RCS的比表面积和总孔体积都有所下降;硝酸改性后,RCS的表面酸性基团含量由0.83 mmol/g提高至3.85 mmol/g;改性前后RCS吸附DBT的等温线可较好地用Freundlich方程进行拟合.     

Comparison between linear and non-linear forms of pseudo-first-order and pseudo-second-order adsorption kinetic models for the removal of methylene blue by activated carbon

The best-fit equations of linear and non-linear forms of the two widely used kinetic models, namely pseudo-first-order and pseudo-second-order equations, were compared in this study. The experimental kinetics of methylene blue adsorption on activated carbon was used for this research. Both the correlation coefficient (R ²) and the normalized standard deviation Δq(%) were employed as error analysis methods to determine the best-fitting equations. The results show that the non-linear forms of pseudo-first-order and pseudo-second-order models were more suitable than the linear forms for fitting the experimental data. The experimental kinetics may have been distorted by linearization of the linear kinetic equations, and thus, the non-linear forms of kinetic equations should be primarily used to obtain the adsorption parameters. In addition, the Δq(%) method for error analysis may be better to determine the best-fitting model in this case.     

粮食安全视角下黄河流域生态保护与高质量发展

黄河流域是我国重要的生态功能区，是实现国家粮食安全的重点区域。本文梳理了近期黄河流域的相关研究，从粮食安全视角下分析了黄河流域现阶段在流域水效率、流域水管理机制、流域水生态文明三方面的问题，并提出了关于黄河流域大保护与高质量发展的两方面建议。一是创新流域水管理机制，服务国家粮食安全。积极改进水资源管理方式，加大节水宣传教育力度，加强黄河流域水土流失综合治理，合理调控水价，完善黄河流域水权市场建设。二是践行"两山"理论，提升流域水生态文明。建设"四大体系"和"七大区域"，推进生态廊道建设；转变经济发展方式；提前布局水生态文明建设。     

PIV experimental study on the flow characteristics upstream of a floating intake in nonlinear stratified ambient conditions

Selective withdrawal is commonly implemented in nonlinearly stratified ambient, which typically has stratified ambient conditions, for purposes of controlling quality. A floating intake is applied as an effective facility of selective withdrawal. However, the outflow dynamics of a floating intake in a nonlinearly stratified ambient have been disregarded, which has a significant effect on the outflow water quality of a reservoir. Experiments were conducted to investigate the effect of thermal stratification on the flow characteristics using particle image velocimetry at three temperature distributions (no stratification, weak stratification and strong stratification). The flow fields upstream of the floating intake showed that the withdrawal layer was formed inhibited by the thermal stratification. And strong stratification produced the thinner withdrawal layer thickness, leading to a larger nonuniform coefficient of the velocity profile. To quantitatively describe the velocity profiles, formulas of dimensionless velocity profiles were proposed. The flow developments were analysed, and the virtual control points located 0.56d above the floating intake (where d is the straight pipe diameter of the floating intake) were obtained. The positions of virtual control points mainly depended on the withdrawal discharge. The decay rate of the velocity along the horizontal line passing through the virtual control point was inversely proportional to the stratification intensity.

     

Flow cytometric analysis of nuclear DNA stained with SYBR Green I in Phaeodactylum tricornutum北大核心CSCD

This study aimed to investigate a suitable method to stain the nuclei of Phaeodactylum tricornutum with a flow cytometer equipped with a 488-nm laser to detect the DNA. Exponentially growing cells were fixed using a 70% ethanol, a 1% glutaraldehyde and a 1% formaldehyde solution, respectively. The samples were treated with RNase A and were then stained with propidium iodide. Samples not treated with RNase A were stained with SYBR-green I. All these samples were observed under a fluorescence microscope and the content of the nuclear DNA was quantitated by flow cytometry. Specific fluoresce spots indicate that fluorescence was detected only in the nuclei of cells stained with SYBR-green I and non-RNase A treated, using fluorescence microscopy. The result of flow cytometry showed that the DNA histogram of cells stained with SYBR-green I had distinct G1 and G2/M peaks, with a fit degree (RCS) of about 3, and a coefficient of variation (CV) of around 8.6%. However, the DNA histograms of cells stained with propidium iodide had a higher CV value, a poor fit degree, and no obvious G1 and G2/M peaks. The results indicate that SYBR Green I is an adequate detection method for nuclear DNA quantitation in cells of P. tricornutum using a flow cytometer equipped with a 488-nm laser, and without RNase A treatment. © 2018 Science Press. All rights reserved.