Mechanical characteristics of dip basement effects on dump stability in the Shengli open pit mine in Inner Mongolia,China

For waste dump slopes that form basements, landslides can be prevented by determining a stability evolving law of dynamic development. Keeping this issue in mind, the relationship between the mechanical structure and stability of waste dumps with basements is studied. Three key factors that influence waste dump stability are presented, and judgment criteria for self-locking and unlocking states of dump basements are provided. From the friction coefficient of waste dump basement stability analyses of the Shengli open pit mine, the results indicate that waste dump basements on the right side of fault F8 and on the left side of fault F61 are subjected to self-locking. However, between faults F61 and F8, the basement is subjected to unlocking. Regarding the residual thrusting of unlocking areas, structure and stability optimization schemes for waste dumps in the Shengli open pit mine are provided through a mechanics analysis. Reducing the slopes and basement angles of waste dumps can enhance their stability by increasing basement roughness levels.     

固相吸附毒素跟踪技术(SPATT)在浙江南麂海域的应用

浙江南麂岛海域是我国近岸贝类的重点养殖区,近年来一直遭受脂溶性贝类毒素(lipophilic shellfish toxins,LSTs)的污染,威胁着人类健康。为了建立有效的食品安全预警方法,本研究利用固相吸附毒素跟踪技术(solid phase adsorption toxin tracking,SPATT)在该海域进行了为期一年的野外监测和LSTs毒素分析。结果表明:7种LSTs毒素在SPATT(DIAION?HP20)中被检出,分别是大田软海绵酸(okadaic acid,OA)、鳍藻毒素-1(dinophysistoxin-1,DTX-1)、虾夷扇贝毒素(yessotoxin,YTX)及其衍生物homo YTX、扇贝毒素-2(pectenotoxin-2,PTX-2)及其衍生物7-epi-PTX2sa和环亚胺毒素(gymnodimine,GYM);有8种毒素在厚壳贻贝(Mytilus galloprovincialis)中被检出,分别是OA、DTX1、homo YTX、PTX2、7-epi-PTX2sa、GYM、原多甲藻酸贝类毒素-3(azaspiracid-3,AZA-3)和虾夷扇贝毒素衍生物45-OH-homo YTX。整体而言,SPATT(HP20)中吸附的毒素种类与贝肉中监测出的毒素种类大体上一致,且两者间OA、DTX1和PTX2的浓度在时间上具有较好的相关性,可见SPATT(HP20)对这些LSTs毒素具有较高的灵敏度,有望作为水体中LSTs毒素的预警监测材料。南麂岛海域LSTs分布特征明显,夏季最高,其次是春秋季,冬季最低,其中2014年夏季贝肉中OA毒素含量高达77.19ng/g贝肉,超出国家限量标准(45ng/g贝肉)比例达11.76%,为浙江南麂海域贻贝的食用安全带来隐患。     

Persistent alternate abundance states in the coral reef sea urchin Diadema savignyi: evidence of alternate attractors

Alternate attractors have been shown to exist in a variety of terrestrial and aquatic systems, e.g. temperate forests, savannas, shallow lakes, wetlands, coral reefs, kelp forests. The shift from one attractor to another, also referred to as a regime shift, is thought to occur when a system passes some critical threshold such that the trajectory of the system changes direction. Alternate attractors in population dynamics can also exist, leading to alternate stable states in the population abundance of a species. This study explored alternate attractors in the population dynamics of the Indo‐Pacific sea urchin Diadema savignyi and the potential underlying mechanisms that promote its bi‐stability. In Moorea, French Polynesia, the local abundance of D. savignyi, a functionally important herbivore in lagoon habitats, occurs in two states: (i) solitary individuals that occupy crevices in low densities and (ii) aggregations of tens to hundreds of individuals. These different states are temporally stable and are not explained by spatial differences in recruitment rates of juveniles. A field experiment revealed that the per capita mortality rate of adult D. savignyi was substantially lower at sites where urchins occurred in aggregations compared with sites at which they were solitary individuals. An additional experiment showed that per capita mortality decreased with increasing aggregation size. Individuals in high‐density aggregations, however, had significantly smaller test diameters than solitary individuals, indicating that individuals in aggregations may be food limited. Collectively, the evidence suggests that the two different local abundance states of D. savignyi result from negative feedback loops where high local density can be maintained by aggregative behavior that greatly reduces per capita risk of predation when the local number of adult sea urchins is sufficiently large; sites with few sea urchins remain at low density because individuals are more susceptible to predation when crevices are occupied but there are not enough individuals to form large aggregations. Thus, there may be alternate attractors in the population dynamics of D. savignyi that can produce either persistently low or high local population densities.     

基于浮标数据的卫星雷达高度计海浪波高数据评价与校正

卫星雷达高度计是海浪有效波高（significant wave height,SWH）观测的重要手段之一,本文利用时空匹配方法对T/P、Jason-1、Envisat、Jason-2、Cryosat-2和HY-2A共6颗卫星雷达高度计SWH数据与NDBC（National Data Buoy Center,NDBC）浮标SWH数据进行对比验证,并对雷达高度计SWH数据进行校正。全部卫星雷达高度计SWH数据时间跨度为1992年9月25日到2015年9月1日,对比验证NDBC浮标共53个,包括7个大洋浮标。精度评价发现除T/P外,各卫星雷达高度计SWH的RMSE都在0.4~0.5 m之间,经过校正后,RMSE都有显著下降,下降程度最大为13.82%;对于大洋浮标,评价结果RMSE在0.20~0.28 m之间,结果明显优于全部NDBC浮标的精度评价结果;HY-2A卫星雷达高度计SWH在经过校正后数据质量与国外其他5颗卫星雷达高度计SWH数据质量差异较小。     

POM模式在日本南部黑潮路径变异研究中的应用

日本南部黑潮路径变异对北太平洋地区的气候和环境具有显著的影响,对黑潮路径变异的研究具有重要的意义。本文利用POM(Princeton Ocean Model)数值模式模拟了日本南部黑潮的路径变异情况,分析了黑潮大弯曲路径形成的可能机制。研究结果表明,当黑潮处于非大弯曲路径时,相对位势涡度的平均值呈现递减趋势,说明日本南部低位势涡度水在不断积累,这样会使得四国再循环流的强度增强,迫使黑潮保持平直路径,同时,近岸黑潮垂直流速剪切增大,斜压不稳定性的作用也逐渐增大;当黑潮从非大弯曲路径向大弯曲路径过渡时,再循环流强度的减弱会导致黑潮的流速剪切减小。根据海表高度异常场以及海洋上层流场信息发现,近岸黑潮附近的气旋涡会随着再循环流区域反气旋涡的东侧向南运动,最终导致黑潮大弯曲的发生。分析涡流的能量,结果显示,黑潮大弯曲路径的形成与斜压不稳定性密切相关。     

Biodegradation of <Emphasis Type="Italic">Enteromorpha</Emphasis> polysaccharides by intestinal micro-community from <Emphasis Type="Italic">Siganus oramin</Emphasis>

Micro-communities are supposed to have more potential functions of biodegradation of polysaccharides than single strain; however, the intestinal micro-communities involved in the biodegradation of Enteromorpha polysaccharides (EP) were seldom reported. In order to obtain the EP-degrading micro-community, the intestines of Siganus oramin was obtained to isolate the micro-communities, which were enriched by 0.3% of EP as the sole carbon source. A stable micro-community with EP degradative capability was achieved after seven generations of subculture, named H1. Results showed that H1 was able to degrade 75% of EP within 24 hours, and the activity of EP lyases reached 500 U mL^?1 in 32 hours. With denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene clone library analysis, ten bacteria closely related to Marinomonas pontica, Microbacterium sp., Leucobacter chironomi, Cyclobacterium sp., Algoriphagus winogradskyi, Pseudoalteromonas sp. and Vibrio sp. were determined. Furthermore, compared with the DGGE bands sequence and the clone library analysis, the dominant bacteria of the EP-biodegrading micro- community were Pseudoalteromonas sp. and Vibrio sp., with the respective proportion of 38% and 46%, and they should play an important role in EP degradation together with other degrading bacteria in the micro-community H1.     

Antialgal and antilarval activities of bioactive compounds extracted from the marine dinoflagellate <Emphasis Type="Italic">Amphidinium carterae</Emphasis>

With the global ban on the application of organotin-based marine coatings by the International Maritime Organization, the development of environmentally friendly, low-toxic and nontoxic antifouling compounds for marine industries has become an urgent need. Marine microorganisms have been considered as a potential source of natural antifoulants. In this study, the antifouling potential of marine dinoflagellate Amphidinium carterae, the toxic and red-tide microalgae, was investigated. We performed a series of operations to extract the bioactive substances from Amphidinium carterae and tested their antialgal and antilarval activities. The crude extract of Amphidinium carterae showed significant antialgal activity and the EC₅₀ value against Skeletonema costatum was 55.4 μg mL^?1. After purification, the isolated bioactive substances (the organic extract C) exhibited much higher antialgal and antilarval activities with EC₅₀ of 12.9 μg mL^?1 against Skeletonema costatum and LC₅₀ of 15.1 μg mL^?1 against Amphibalanus amphitrite larvae. Subsequently, IR, Q-TOFMS, and GC-MS were utilized for the structural elucidation of the bioactive compounds, and a series of unsaturated and saturated 16- to 22-carbon fatty acids were detected. The data suggested the bioactive compounds isolated from Amphidinium carterae exhibited a significant inhibiting effect against the diatom Skeletonema costatum and Amphibalanus amphitrite larvae, and could be substitutes for persistent, toxic antifouling compounds.     

New variogram modeling method using MGGP and SVR

A critical step for kriging in geostatistics is estimation of the variogram. Traditional variogram modeling comprise of the experimental variogram calculation, appropriate variogram model selection and model parameter determination. Selecting of the variogram model and fitting of model parameters is the most controversial aspect of geostatistics. Shapes of valid variogram models are finite, and sometimes, the optimal shape of the model can not be fitted, leading to reduced estimation accuracy. In this paper, a new method is presented to automatically construct a model shape and fit model parameters to experimental variograms using Support Vector Regression (SVR) and Multi-Gene Genetic Programming (MGGP). The proposed method does not require the selection of a variogram model and can directly provide the model shape and parameters of the optimal variogram. The validity of the proposed method is demonstrated in a number of cases.