Geographical variation in parasitism shapes larval immune function in a phytophagous insect

Two of the central goals of immunoecology are to understand natural variation in the immune system among populations and to identify those selection pressures that shape immune traits. Maintenance of the immune system can be costly, and both food quality and parasitism selection pressure are factors potentially driving immunocompetence. In tritrophic interactions involving phytophagous insects, host plants, and natural enemies, the immunocompetence of phytophagous insects is constrained by selective forces from both the host plants and the natural enemies. Here, we assessed the roles of host plants and natural enemies as selective pressures on immune variation among natural populations of Lobesia botrana. Our results showed marked geographical variation in immune defenses and parasitism among different natural populations. Larval immune functions were dependent of the host plant quality and were positively correlated to parasitism, suggesting that parasitoids select for greater investment into immunity in moth. Furthermore, investment in immune defense was negatively correlated with body size, suggesting that it is metabolically expensive. The findings emphasize the roles of host plants and parasitoids as selective forces shaping host immune functions in natural conditions. We argue that kinds of study are central to understanding natural variations in immune functions, and the selective forces beyond.     

预氧化技术在油田污水处理中的应用研究

预氧化技术是随着油田污水处理的需要发展起来的一种新技术。预氧化的目的就是把二价铁离子转化为三价铁,并在后期通过添加化学药剂沉淀出来,从而提高水质稳定性,降低后续处理过程的结垢现象。目前采用的预氧化技术主要有两种:化学预氧化和电化学预氧化。详细介绍预氧化技术,并通过与传统工艺技术的对比总结了预氧化技术的特点;分析了两种预氧化技术的异同;并通过这两种技术在油田的实际应用情况对它们的应用水质、运行管理、加药情况等方面进行了对比研究,总结了两种技术的优缺点及适用水质,并对该技术以后的推广应用提出相应建议。     

1960年-2014年天山北麓气温和降水变化趋势及预测研究

利用天山北麓17个气象站点1960年-2014年的气温和降水资料,采用Morlet小波分析、R/S分析等,研究了天山北麓气温和降水的时间变化.结果表明,(1)天山北麓年平均气温和年降水量分别以0.035℃/a和0.881 mm/a的倾向率呈上升趋势;季节变化明显;(2)年平均气温和年降水量有明显的周期性,年平均气温在55 a尺度内存在13 a的强显著周期,年降水量在55 a尺度内存在8 a的强显著周期.(3)未来一段时间内,天山北麓气温和降水均呈上升趋势,且与过去的变化趋势持续性较强.     

Vision-independent odometry in the ant Cataglyphis cursor

In contrast to flying insects, in which distance estimation is visually mediated, self-induced image motion and use of familiar landmarks are known to play a minor role in ants. Here we show that strictly diurnal Cataglyphis cursor ants can gauge with accuracy the distance they have travelled even in complete darkness in the absence of any other cues, i.e. chemical or protocounting information. Thus, an ants odometer is a vision-independent system based on proprioceptive cues, implicating some form of step counting, which remain to be elucidated.     

小龙潭电厂脱硫工艺的探讨

介绍了国外几种成熟的脱硫工艺，通过分析与比较并结合小龙潭电厂的实际情况，最终选择烟气循环流化床半干法作为该电厂褐煤锅炉的脱硫工艺。     

Spring abundance and distribution of the ctenophore Pleurobrachia pileus in the Seine estuary: advective transport and diel vertical migration

Several sets of plankton and hyperbenthos samples were collected from the Seine estuary in late May-early June of 1991, 1992 and 1994, and the abundance, size-frequency, horizontal and vertical distribution, and short-term fluctuations of Pleurobrachia pileus (O.F. Müller, 1776) were determined. In the Seine estuary, P. pileus was more abundant than reported for any other European shallow waters. Its depth-averaged density was 33 individuals m^-3 in 1991 and 32 individuals m^-3 in 1992, with a maximum density of 808 individuals m^-3. The ctenophores displayed passive tidal advection and active diel vertical migration. In the outer estuary, high abundances were observed around low tide, and diel vertical migration was very pronounced. However, many individuals remained aggregated near the bottom at all times. In spring, the distribution of P. pileus coincided with the 33 and 150 S isohalines, with high abundances on the marine side of the estuary. It is suggested that aggregation of ctenophores near the bottom and diel vertical migration play an important role in the retention of P. pileus in the estuary. Two schemes of P. pileus life cycle in the Bay of Seine are proposed.     

区域农业持续性与持续发展研究

景观生态学属于宏观尺度生态空间研究范畴，它的理论核心集中表现为空间异质性和生态整体性两方面。持续性，包括农业景观持续性的最终目标在于人类与其环境的整体协调，即广义的人类生态整体性。持续性研究涉及广阔的地域空间，其目标的实现则有赖于空间途径。这一认识是将景观生态学应用于持续农业发展的理论出发点。     

Mobility of heavy metals associated with the natural weathering of coal mine spoils

Knowledge of chemical mobility of heavy metals is fundamental to understanding their toxicity, bioavailability, and geochemical behavior. In this paper, two different methods, i.e. mineralogical means and sequential extractions, were employed to analyze the total contents, existing states, and chemical forms of heavy metals in coal mine spoils. The results demonstrate that the mobility of heavy metals in coal mine spoils depends not only on their existing states and the stability of their host minerals but also on the properties of the coal mine spoils. In the process of coal mine spoils-water interaction, sulfides that contain heavy metals first break down and release metals, which are then adsorbed and complexed by the iron oxyhydroxide colloid resulting from pyrite oxidization and organic matter. During the natural weathering of coal mine spoils, only a small fraction of these metals are released to the environment, and most of them still remains in the residual material.     

磁黄铁矿氧化机理及酸性矿山废水防治的研究进展

磁黄铁矿是矿山尾矿堆中最为常见且分布很广的一种硫化铁矿物.由于硫化物矿物氧化后不仅产生酸性废水,还会释放出大量可溶的、生物可利用形态的微量金属,并且酸性环境会进一步增强这些有毒金属的移动性,因此是造成矿山周围水体环境污染的罪魁祸首.为了阻止或降低磁黄铁矿的自然风化反应速度从而达到源头治理酸性矿山废水的目的,首先必须研究它在各种条件下的氧化机理、氧化产物和氧化速度.对近年来国外在磁黄铁矿晶体结构、反应活性以及酸性矿山废水的产生与防治等方面的研究进行了综述.