Neurotoxicity and transcriptome changes in embryonic zebrafish induced by halobenzoquinone exposure

Halobenzoquinones(HBQs) are emerging disinfection byproducts(DBPs) with a widespread presence in drinking water that exhibit much higher cytotoxicity than regulated DBPs. However, the developmental neurotoxicity of HBQs has not been studied in vivo. In this work, we studied the neurotoxicity of HBQs on zebrafish embryos, after exposure to varying concentrations(0-8 μmol/L) of three HBQs, 2,5-dichloro-1,4-benzoquinone(2,5-DCBQ), 2,6-dichloro-1,4-benzoquinone(2,6-DCBQ), and 2,5-dibromo-1,4-benzoqu...     

美国区域碳封存联盟对我国推进CCS工作的启示

美国能源部提出的美国区域碳封存联盟(Regional Carbon Sequestration Partnerships,RCSPs)是美联邦政府推动碳捕集与封存(Carbon Capture and Storage,CCS)技术发展的组织,该联盟旨在从技术研发和基础设施建设角度构建一个基础架构。RCSPs的提出及所取得的成果,为美国部署CCS技术奠定了基础,本文通过分析RCSPs三个发展阶段及取得的成果为我国CCS技术的示范和部署工作带来启示。     

Set a thief to catch a thief: brown-necked raven (Corvus ruficollis) cooperatively kleptoparasitize Egyptian vulture (Neophron percnopterus)

Our study describes how brown-necked ravens (Corvus ruficollis) are able to take advantage of an ordinarily inaccessible, high-quality food source by relying upon their innovative and manipulative thinking capabilities to exploit methods used by Egyptian vulture (Neophron percnopterus) to overcome the problem. In five observed interactions, the ravens were first seen in the vicinity of an abandoned clutch of ostrich eggs (Struthio camelus). The area was frequented by a pair of Egyptian vultures that bred on the cliffs across the road from the nature reserve. The Egyptian vulture exhibits tool use in birds, and is able to crack the hard shells of ostrich eggs by lifting a rock in the beak and pounding at the egg till it breaks open or cracks. If the egg is only cracked, the vulture inserts its narrow bill into the fissure and widens it by opening the mandibles. Pieces of eggshell are removed from around the crack in order to further open the egg. This is the point at which the pair of ravens attacked the vulture and harassed it till it abandoned the egg and left the area. The ravens then jointly enjoyed the contents of the egg which was otherwise inaccessible to them because of the strong egg shell.     

氰化物生物降解法的优越性

矿业加工废水中的氰化物的生物降解法和有毒金属的生物吸着法是具有许多起超于化学处理法的优越性的技术。其优点包括;成本效率高,处理性能好,抗干扰,产生的残渣少,金属脱除率与回收率高,灵敏的设计特性,接受流出液,液流的适应性好和有随过程条件改变而自动调节的能力。     

散粒物料加工中粉尘爆炸的预防

加工处理散粒物料时通常会产生并散发粉尘。有些加工作业过程,例如将麦子磨成面粉,所产生的粉尘浓度可能很高。其他作业过程,诸如将煤倾卸入溜槽或运到输送机上所造成的粉尘问题虽然不很严重,但还会产生大量的微细粒子。粉尘引起的问题,视加工处理的物质而异。如果是贵重物质,粉尘会引起可观的经济损失;若是有害物质,粉尘会危害健康;第三种情况是微细物料可能构成爆炸事故。令人意外的是,许多通常认为是非爆炸性的物质,如阿斯匹林、可可、大多数金属、木材和糖,在微粒状态下很可能发生爆炸。如     

用于包装的振动试验

由于振动与冲击作用的周期时间不同,可认为这两者是有差别的。振动持续的时间较长,而冲击出现的时间间隔较短。 在包装领域,因为冲击脉冲幅值往往比振动幅值大很多,所以有时候存在忽略振动的倾向。由于在各共振频率处的振幅很大,振动可能造成结构的损坏。如果被包装产品中的共振频率与包装缓冲器的频率一致或接近的话,则包装内就可能出现这种损坏现象。     

重金属由衣菌到尾核草履虫的生物选择传递

衣菌是存在于污水中的细菌,己发现它能吞食锌、铝、镍和锰。该细菌的含金属培养物又被用来饲养原生动物尾核尊履虫、并且分析结果揭示了对锌、铝和镍的蓄积作用。在这一研究中,因为衣菌是草履虫的唯一食料源,所以此结果表明那些痕量金属是通过一种捕食与被捕食的关系,是经由细菌转移到原虫的。     

草地生态系统的生物地球化学循环

引言在一个生态系统内,如果没有遭受象耕种、生产农作物和施用肥料这样的周期性干扰,那么我们就把这个生态系统看成一个无干扰系统,象天然草地。由此也就利用这样有益环境,研究这种生态系统中包括N和P循环在内的许多过程的相互影响。对于热带生态系统,人们进行过上述研究,但可参阅的论文很少。目前的研究是要在印度占西(Jhansi)Aif Field牧场的Sehima村落对植物N和P的含量进行竹算。     

美国的地震危险性

<正> 1 地震危险性评定历史早期地震建筑规范的技术要求是根据Algermieecn(1969)的初步工作——总结本国最大历史烈度,而Cornell(1968)的工作则是确立了对点源的概率地震危险性分析演绎法。该方法要求定义震源,震级分布和衰减函数,然后对所有可能的地震震级和距离进行积分来计算地震危险性。Merz和Cornell(1973),McGuire(1976,1978),Der Kiureghian和Aug(1977)将该方法推广到能包括非指数震级分布和断层源的研究。美国地质调查局也采纳了该演绎法,并将其应用到全国范围(Algermissen和Rerhins,1976),同时合并震源和最大震级的输入范围。McGuire(1974,1977)采用谱参数(而不是峰值运动参数)第一个示范了地震危险性方法。该方法以TAC—3(1987)模型建筑规范格式应用于全国。     

Land-cover change in upper Barataria Basin estuary,Louisiana, 1972-1992: increases in Wetland area

The Barataria Basin, Louisiana, USA, is an extensive wetland and coastal estuary system of great economic and intrinsic value. Although high rates of wetland loss along the coastal margin of the Barataria Basin have been well documented, little information exists on whether freshwater wetlands in the upper basin have changed. Our objectives were to quantify land-cover change in the upper basin over 20 years from 1972–1992 and to determine land-cover transition rates among land-cover types. Using 80-m resolution Landsat MSS data from the North American Landscape Characterization (NALC) data archive, we classified images from three time steps (1972, 1985, 1992) into six land-cover types: agriculture, urban, bottomland hardwood forest, swamp forest, freshwater marsh, and open water. Significant changes in land cover occurred within the upper Barataria Basin over the study period. Urban land increased from 8% to 17% of the total upper basin area, primarily due to conversions from agricultural land, and to a lesser degree, bottomland forest. Swamp forest increased from 30% to 41%, associated with conversions from bottomland hardwood forest and freshwater marsh. Overall, bottomland forest decreased 38% and total wetland area increased 21%. Within the upper Barataria, increases in total wetland area may be due to land subsidence. Based on our results, if present trends in the reduction of bottomland forest land cover were to continue, the upper Barataria Basin may have no bottomland hardwood forests left by the year 2025, as it is subjected to multiple stressors both in the higher elevations (from urbanization) and lower elevations (most likely from land subsidence). These results suggest that changes in the upper freshwater portions of coastal estuaries can be large and quite different from patterns observed in the more saline coastal margins.