发展家庭经济与区域资源的关系

家庭经济是农村经济的重要组成部分,它适应了区域资源的固有特征,因而在较长时期内仍将在我国农村广泛存在。但是,由于经营权的自主性和决策能力的先天不足,使家庭经济在其发展的每个阶段和生产经营的各个过程都暴露出种种矛盾,制约着家庭经济的发展,这就要求我们必须通过各种途径,引导自发的家庭经济向立足本地资源的产业模式集结,逐步形成各具特色的家庭经济小区。     

红外图谱计算机解析研究

本文提供了被认为比较准确的32种有机分子特征基团红外光谱吸收范围;提出了红外仪扫描时计算机同时采集数据,红外扫描结束后,计算机不用人工干予自动利用有机分子基团的特征吸收峰的峰位、强度信息判断有机分子所含基团的图谱解析方法。并提供了程序设计框图。给出了40个较有代表性化合物的图谱解析实验结果。     

Sonographic features of ileal duplication cyst at 12 weeks

Enteric duplication cyst is a congenital abnormality that is believed to arise from abnormal recanalization of the bowel during embryogenesis. Previous reports suggest that the condition may be suspected prenatally by sonographic demonstration of an intra-abdominal cystic mass in the second and third trimesters. We present the sonographic features of a fetus with ileal duplication cyst at 12 weeks of gestation, which show that the condition may present in the first trimester of pregnancy. Copyright © 2002 John Wiley & Sons, Ltd.     

滇池污染的综合治理与管理对策研究

根据近年来滇池污染综合治理的情况,提出了滇池流域污染综合治理对策.即用系统科学的方法,围绕水污染控制、水资源开发利用和生态恢复三大问题,进行环境工程治理和生态环境治理的对策措施研究,并在此基础上从滇池环境管理的角度,提出建立机制、制定政策、强化各项监督管理工作、依法治湖等管理对策.     

Co-present Pb(II) accelerates the oxidation of organic contaminants by permanganate: Role of Pb(III)

• Simultaneous removal of organic contaminants and Pb(II) was achieved by Mn(VII). • Pb(II) enhanced Mn(VII) oxidation performance over a wide pH range. • Pb(II) did not alter the pH-rate profile for contaminants oxidation by Mn(VII). • Mn(VII) alone cannot oxidize Pb(II) effectively at pH below 5.0. • Pb(III) plays important roles on enhancing Mn(VII) decontamination process. The permanganate (Mn(VII)) oxidation has emerged as a promising technology for the remediation and treatment of the groundwater and surface water contaminated with the organic compounds. Nonetheless, only a few studies have been conducted to explore the role of the heavy metals (especially the redox-active ones) during the Mn(VII) oxidation process. In this study, taking Pb(II) as an example, its influence on the Mn(VII) decontamination performance has been extensively investigated. It was found that, with the presence of Pb(II), Mn(VII) could degrade diclofenac (DCF), 2,4-dichlorophenol, and aniline more effectively than without. For instance, over a wide pH range of 4.5–8.0, the dosing of 10 μmol/L Pb(II) accelerated the DCF removal rate from 0.006–0.25 min⁻¹ to 0.05–0.46 min⁻¹ with a promotion factor of 1.9–9.4. Although the UV-vis spectroscopic and high resolution transmission electron microscopy analyses suggested that Mn(VII) could react with Pb(II) to produce Mn(IV) and Pb(IV) at pH 6.0–8.0, further experiments revealed that Pb(II) did not exert its enhancing effect through promoting the generation of MnO₂, as the reactivity of MnO₂ was poor under the employed pH range. At pH below 5.0, it was interesting to find that, a negligible amount of MnO₂ was formed in the Mn(VII)/Pb(II) system in the absence of contaminants, while once MnO₂ was generated in the presence of contaminants, it could catalyze the Pb(II) oxidation to Pb(IV) by Mn(VII). Collectively, by highlighting the conversion process of Pb(II) to Pb(IV) by either Mn(VII) or MnO₂, the reactive Pb(III) intermediates were proposed to account for the Pb(II) enhancement effect.     

Effects of perfluorooctanoic acid (PFOA) on activated sludge microbial community under aerobic and anaerobic conditions

Environmental Science and Pollution Research - Per- and polyfluoroalkyl substances (PFASs) have received increasing attention due to their widespread presence in diverse environments including...     

Warning signals confer advantage to prey in competition with predators: bumblebees steal nests from insectivorous birds

Aposematic (warning) signals of prey help predators to recognize the defended distasteful or poisonous prey that should be avoided. The evolution of aposematism in the context of predation has been in the center of modern ecology for a long time. But, the possible roles of aposematic signals in other ecological contexts have been largely ignored. Here we address the role of aposematic signals in competition between prey and predators. Bumblebees use visual and auditory aposematic signals to warn predators about their defenses. For 2 years, we observed competition for nestboxes between chemically defended insects, Bombus ardens (and possibly also Bombus ignitus), and cavity nesting birds (Parus minor and Poecile varius). Bumblebees settled in 16 and 9 % of nestboxes (in 2010 and 2011 breeding seasons, respectively) that contained bird nests at the advanced stage of nest building or at the stage of egg laying. Presence of bumblebees prevented the birds from continuing the breeding activities in the nestboxes, while insects took over the birds’ nests (a form of kleptoparasitism). Playback experiments showed that the warning buzz by bumblebees contributed to the success in ousting the birds from their nests. This demonstrates that aposematic signals may be beneficial also in the context of resource competition.     

Morphologically plastic responses to shading in the zoanthids Zoanthus sansibaricus and Palythoa tuberculosa

Zoanthids of the order Zoantharia (Anthozoa: Hexacorallia) exhibit high intraspecific morphological variability, but whether this is due to polymorphism, phenotypic plasticity or a combination of both remains unknown. To address this knowledge gap, in November 2010, eight colonies each of Zoanthus sansibaricus and Palythoa tuberculosa were sampled from three reefs off the south of mainland Singapore and transplanted to a shallow experimental site. The colonies were then distributed under two types of treatment frames: control and shaded. After 87 days, morphometric characters were extracted from macro-images. Reaction norms, principal components analysis, analysis of variance and canonical discriminant analysis all demonstrated light-induced changes in morphology. Patterns of plastic changes were similar for both species: shaded colonies had larger polyps as compared to control colonies. The presence of plastic responses in zoanthids may facilitate their colonization of a broad range of habitats as well as help them to withstand temporal changes in their environment.     

The role of rooted emergent vegetation on periodically thermal-driven flow over a sloping bottom

Thermal-driven flow is generated due to topographic or vegetation-shading effects. Asymptotic solutions by assuming a small bottom slope are derived to discuss effects of rooted emergent vegetation and interactions between emergent vegetation and sloping topography on thermal-driven flow during diurnal heating and cooling cycles. The results show that the zero-order horizontal velocity is significantly reduced by vegetative drag, and the time lag between the change of horizontal velocity and the reversal of pressure gradient is also shortened. The solutions reveal that the viscous effect is dominant in very shallow water, and the drag force becomes important as the water depth increases. The inertial term is only important at the very beginning stage of flow initiation. Different vegetation distributions can significantly change the temperature fields that then affect patterns of thermal-driven circulation and exchange flowrates. For the case of tall vegetation growth in shallow water, and when the deep water side is open, the effects of vegetation shading may interfere with the topographic effects and dramatically alter the flow patterns. The blockage of solar radiation due to vegetation shading can determine the patterns and magnitude of thermal-driven flow. By means of the derived asymptotic horizontal velocity, exchange flow rates can be estimated, which are in good agreement with previous studies. The limitation and valid ranges of asymptotic solutions are finally discussed.