The predatory mite Phytoseiulus persimilis manipulates imprinting among offspring through egg placement

A crucial question with respect to imprinting is how animals ensure that kin imprint on kin but not on non-kin. Imprinting takes place in a sensitive ontogenetic phase, usually in an early period of life or when offspring are produced, at which time the recipient imprints on the first referents met. In the predatory mite Phytoseiulus persimilis, imprinting among immature individuals happens in the larval stage immediately after hatching. I tested the hypothesis that adult P. persimilis females manipulate offspring imprinting by influencing the likelihood of encounters among recipients and referents via egg placement and egg aggregation. I conducted two experiments, one of which addressed imprinting and cannibalism, and the other addressed egg placement and egg aggregation. The imprinting experiment suggests that larvae imprint on any conspecific individual met in a sensitive ontogenetic phase and later on treat this individual as kin, irrespective of relatedness. After molting to protonymphs, imprinted individuals preferentially cannibalized unfamiliar to familiar larvae. Irrespective of familiarity, kin were cannibalized earlier than non-kin, suggesting the involvement of self-referent phenotype matching. The egg-placement experiment provides evidence that females adjust the aggregation level of their own eggs according to the degree of relatedness to present eggs from a previously ovipositing female. Both experiments in concert suggest that egg placement is a maternal strategy influencing imprinting among immature individuals. Apart from avoiding kin cannibalism, egg placement and imprinting by larvae may have relevance to other behaviors influenced by kin recognition, such as mate choice, prey-patch choice and dispersal.Communicated by L. Simmons     

城市热岛效应研究进展

作为现代城市气候主要特征之一的城市热岛效应有日渐严重的趋势。文章综述了城市热岛的生态环境效应、热岛的主要形成机制、时空分布特征等研究状况和发展趋势；基于当前城市热岛研究的现状，提出了未来城市热岛效应研究的方向及缓解城市热岛效应的有关对策。     

Changes of Soil Microbiological Properties Caused by Land Use Changing From Rice–Wheat Rotation to Vegetable Cultivation

A survey was done recently in Jiaxing city of Zhejiang Province in the Yangtze River Delta to compare the differences of soil microbiological properties among paddy soils with different land use including continuous open-field vegetable cultivation (OFVC), plastic-greenhouse vegetable cultivation (PGVC) and traditional rice–wheat rotation (RWR). The soil types included are percolating, permeable and waterlogged paddy soils. The results indicate that the microbial flora was markedly changed as the land use changed for all the three soil types. In continuous vegetable cultivation soils, especially in PGVC soils, the bacteria amounts decreased dramatically, but the fungal and actinomyce amounts increased as compared with RWR soils. The dehydrogenase activities decreased significantly in vegetable soils, especially in PGVC soils as compared with RWR soils. The microbial biomass C and the total phospholipid contents (TPL) in vegetable cultivation soil greatly decreased as compared with RWR soils. Biolog analysis indicated that the kinds of carbon sources that could be metabolized by native microbes in PGVC soils greatly decreased as compared with OFVC soils and RWR soils, revealing that microbial diversity had decreased since land use change. The activities of some soil enzymes including urease, invertase and phosphase were all lower in OFVC soils than those in RWR soils, and those in PGVC soils were the lowest. The degradation of microbiological activities in continuous vegetable cultivation soils, especially in PGVC soils, as compared with RWR soils might have been caused by soil acidification and accumulation of salts due to overuse of both organic and inorganic fertilizers in vegetable cultivation.     

三峡工程淹没区文物古迹科学保护方案的探讨

对于三峡工程没区文物群落的保护,不只限于其文物价值的研究,文物的保存环境及现状的评估更是采取科学保护方案的先决条件。从地面石抽文物的原位测试技术和地下文物的考古勘探技术两方面以实例和详细的数据,介绍了在三峡工程没区文物保护工程前 的科学     

以关键酶为基础共代谢模型的建立——以甲烷细菌共代谢三氯乙烯为例

根据共代谢过程扣特点，详细推导建立了一个以关键酶为中心的综合性数学模型，模型不仅包括传统的基质降解迷率和微生物生长，而且包括关键产诱导，毒性抑制和自我恢复，以及能量的调节等重要因素，模型能够在理解释文献报道的各种实验现象。     

海南三亚近岸海域水化学要素的分布特征和变化规律

本文调查研究了海南三亚近岸海域水化学要素的浓度和分布，结果表明：（１）表层ＤＯ、ＮＯ－２、ＮＯ－３、ＮＨ＋４、ＰＯ３－４和ＣＯＤ的平均浓度分别为４１１．９、０．０５、０．４７、１．７９、０．１６μｍｏｌ／ｄｍ３和１．３１ｍｇ／Ｌ。（２）河流输入对沿岸海域水化学要素的影响主要集中于ＮＨ＋４和ＣＯＤ，对ＰＯ３－４和ＮＯ－３的浓度影响不明显，海域总体为一贫营养盐区域。采用主成分分析表明控制水化学要素的主要因子是河流的输入和由此导致了的生物旺发。     

无锡太湖新城污水处理厂改良型A^2／O工艺的调试与运行

介绍了无锡市太湖新城污水处理厂的一期工程设计概况和所采用的改良型A^2/O脱氮除磷工艺，分析、探讨了污水处理厂的调试、培菌、试运行过程中出现的问题，并针对性地采用了一系列的解决措施。由监测数据表明，该工艺运行可靠，出水水质稳定，实现了污水处理厂的正常运行。     

中国九十年代城市环境污染控制战略(下)

80年代是我国城市社会经济发展最快的时期,城市化水平由1981年的14.3％提高到1990年的21％,城市规模结构趋向合理,形成了以大城市为中心,中等城市为骨干和小城市为纽带的城市结构。但应该清醒的是,我国绝大部分城市的经济发展水平与工业     

水污染·水资源·对策

本文详细论述了中国和世界的水资源状况，并论述了中国的水资源短缺状况、中国用水的优劣势，以及如何解决中国水资源短缺的措施和基本战略。     

青藏高原重点区域工业布局的战略构想

论文认为在青藏高原具有相对比较优势的重点区域 ,应大力发展具有特色的现代工业。作者重点分析了高原重点区域工业发展的总体思路和战略目标 ,指出了工业发展的总体方向和区域工业布局框架设想。从协调好高原各个产业之间的相互关系出发 ,文章认为在高原重点区域应大力发展以钢铁-铁合金-有色-黄金为主的冶金工业 ,以盐化和油气化工为主的化学工业 ,以满足高原内部需要的建材工业 ,以及具有一定基础的机电-轻纺和藏民族手工业。