异丙甲草胺与锌共存对斜生栅藻毒性手性差异影响

为评价重金属与手性农药共存的生物选择性毒性,采用毒性试验标准方法研究了Rac-、S-异丙甲草胺单独及与锌共存对斜生栅藻的手性毒性差异.结果表明,Zn2+存在条件下Rac-、S-异丙甲草胺对斜生栅藻的生长趋势影响与除草剂单独作用时的趋势基本相同,Zn2+的存在降低了高浓度除草剂对斜生栅藻的生长抑制作用,处理初期(24 h)0.30 mg·L-1Rac-和S-异丙甲草胺单独对斜生栅藻生长的抑制率分别为49.61%和59.73%,与Zn2+联合作用其抑制率分别为38.41%和42.52%.Zn2+的存在增加了Rac-和S-异丙甲草胺对斜生栅藻的立体选择性毒性差异,使S-异丙甲草胺急性毒性增大的程度大于Rac-异丙甲草胺毒性的增加;与Zn2+的联合毒性作用类型表现为除草剂在低浓度下为部分相加作用,高浓度下为拮抗作用;除草剂单独及与Zn2+联合作用处理96 h后的斜生栅藻叶绿素含量变化与其生长趋势基本一致.     

The oil industry along the Atlantic coast of Cameroon: Assessing impacts and possible solutions

While the oil industry along the Atlantic coast of Cameroon has made important contributions to the national economy, this has been accompanied with adverse environmental impacts. There has been significant pollution from oil drilling, refinery waste, oil spillage, gas and flaring. After discussing these impacts, this paper argues that prevailing regulations are inadequate and need overhauling. It proposes that cleaner production requires:

(i)

specific laws to protect dwellers in the neighbourhood of oil refineries, filling stations, service stations and pipelines;     

Individual-based modelling of fishermen search behaviour with neural networks and reinforcement learning

A model to mimic the search behaviour of fishermen is built with two neural networks to cope with two separate decision-making processes in fishing activities. One neural network deals with decisions to stay or move to new fishing grounds and the other is constructed for the purpose of finding prey within the fishing areas. Some similarities with the behaviour of real fishermen are found: concentrated local search once a prey has been located to increase the probability of remaining near a prey patch and the straightforward movement to other fishing grounds. The artificial fisherman prefers areas near the port when conditions in different fishing grounds are similar or when there is high uncertainty in its world. In the latter case a reluctance to navigate to other areas is observed. The artificial fisherman selects areas with higher concentration of prey, even if they are far from the port of departure, unless a high uncertainty is related to the fishing ground. Connected areas are preferred and followed in orderly fashion if a higher catch is expected. The observed behaviour of the artificial fisherman in uncertain scenarios can be described as a risk-averse attitude. The approach seems appropriate for an individual-based modelling of fishery systems, focusing on the learning and adaptive characteristics of fishermen and on interactions that take place at a fine scale.     

Social dimensions of mining: Research,policy and practice challenges for the minerals industry in Australia

The social dimensions of the mining industry are increasingly acknowledged as critical to business success, yet remain the least understood aspect of the business concept of sustainable development—the ‘triple bottom line’ of economy, environment and society.     

DESALTING SALINE WATER FOR IRRIGATION A CASE STUDY,COACHELLA AREA,CALIFORNIA1

ABSTRACT .A case study was performed to evaluate potential applications of desalted saline water for agriculture using 2 distillation type processes and 2 membrane type processes. The investigation determined the costs and benefits associated with desalting saline water at concentrations of 1,500, 900, 400, 200, and 50 ppm. Benefits from desalting are generated by shifts to more profitable crops, reduced costs for drainage, and reduction in fertilizer and labor requirements with better quality water. Costs are based on the project features such as desalting plants, raw water diversion facilities, storage reservoirs, conveyance and distribution systems, brine disposal, blending facilities, and gypsum addition systems. Hydrologic studies determined the crop irrigation requirements, water demand schedules, desalted water storage requirements, brine disposal requirements, and size of facilities required. Reconnaissance design layouts were made for producing desalted water using a combination of 14 schemes. The study also included a review of irrigation practices. The benefit-cost ratios range from 0.4 to 1.0 for 1,500 ppm irrigation water to 0.8 to 1.0 for 50 and 200 ppm water. Investment costs per acre are high, ranging from $12,900 to $20,900. Irrigation benefits are based on the increase in production from a desert condition with no water supply to the irrigation conditions studied.     

Q235钢在火灾条件下的力学性能研究

在试验的基础上,对建筑中常用的Q235铜在火灾条件下的力学性能进行了研究,获得了Q235钢的屈服强度、极限强度、弹性模量、极限应变等力学性能随温度变化而变化的规律,并对影响Q235钢力学性能的因素进行了分析。     

乙醛对鱼类毒性的实验研究

介绍了实验室乙醛对鲢鱼幼鱼的急性毒性。试验结果表明，乙醛对鲢鱼幼鱼的急性毒性４８ｈＬＣ５０为１４６１８ｍｇ／Ｌ，其安全浓度为１４６２ｍｇ／Ｌ。     

工频磁场诱导人FL细胞膜EGF的受体聚簇及噪声磁场的干预

为了研究50Hz工频磁场对人源细胞膜表皮生长因子(epidermal growth factor,EGF)的受体聚簇现象的可能诱导作用及噪声磁场的干预,将人羊膜细胞FL(human amniotic cells)分别用EGF、不同强度(0.05、0.1、0.2、0.4mT)工频磁场、噪声磁场、工频磁场和噪声磁场叠加的复合场处理15 min后,用间接免疫荧光染色法标记,并用激光共聚焦显微镜观察细胞膜表皮生长因子(EGF)的受体的聚簇现象.结果表明,0.1、0.2、0.4mT工频磁场辐照FL细胞15 min可诱导细胞膜EGF的受体发生聚簇,但0.05mT工频磁场辐照时,细胞膜不出现EGF受体的明显聚簇.0.2mT噪声磁场则不能诱导细胞膜EGF受体的聚簇;当0.2mT噪声磁场与0.1、0.2mT工频磁场叠加后,可抑制工频磁场诱导的细胞膜EGF受体聚簇,但不能完全抑制0.4mT工频磁场诱导的细胞膜EGF受体聚簇.研究结果表明,一定强度的工频磁场能诱导细胞膜EGF受体的聚簇;其作用阈值在0.05～0.1mT之间;噪声磁场对工频磁场诱导膜受体聚簇的干预作用存在剂量-效应关系.     

高地应力条件下Q系统在某勘探洞围岩分类中的应用

西南地区某水电站勘探洞高地应力是一个突出问题,高地应力洞段岩体属于坚硬岩或较坚硬岩,主要破坏方式是岩爆。高地应力区非岩爆岩体中未见结构性流变和软岩塑性流动等变形破坏现象,岩体质量较好。通过对岩体质量分类Q系统在该勘探洞高地应力洞段的应用,发现Q系统对于高地应力区非岩爆段岩体没有给出相应的SRF值;岩爆的发育条件是多方面的,但Q系统对岩爆的发育条件考虑较单一,所以它在高地应力区岩爆段的分类结果不能准确地体现出岩爆的等级和围岩类别。基于这2个问题,本文对Q系统做了相应的修改,以适应该勘探洞围岩分类,从修改后Q系统的分类结果看,效果良好。     

硝基芳族化合物对江水细菌的毒性及QSAR研究

采用细菌生长抑制实验,测定了２４种硝莽主族化合物对松花江水中细菌的毒性,得到２４ｈ－ＩＣ５０值,并选用５种物理化学参数ｌｇＰ、＾１Ｘ＾ｖ、Ｉ、∑σ＾－、ＥＬＵＭＯ对毒性数据进行量结构活性关系研究。