Effects of costs and benefits of brood care on filial cannibalism in the sand goby

This study tested experimentally whether clutch size and the cost of care affect filial cannibalism in the sand goby, Pomatoschistus minutus. Evolutionary models of filial cannibalism suggest that egg eating has evolved as a way for the male parent to prolong his breeding season. These models assume that eggs function as an alternative energy source for the constrained parent. I manipulated clutch size by allowing males to mate with either one or two females, representing a small and a large clutch, respectively. The addition of a small male shore crab, a common egg predator, increased the cost of care. I quantified fat reserves as a measure of the condition of guarding males. Males who did not build nests had lower fat reserves than males who built nests, suggesting that males with low energy reserves do not start breeding. Males with small clutches lost their nest to the crab more often than males with large clutches. Neither filial cannibalism nor the amount of eggs eaten were affected by the treatments. Males who consumed eggs had a higher fat percentage than males who did not eat eggs. The result that males with small clutches lost their nests to the crabs supports the idea that eggs are defended only if the benefit from continued care will outweigh the cost and that males therefore are sensitive to the trade-off between present and future reproductive success. Received: 15 May 1997 / Accepted after revision: 15 November 1997     

Biodegradation of triclosan and formation of methyl-triclosan in activated sludge under aerobic conditions

Triclosan is an antimicrobial agent which is widely used in household and personal care products. Widespread use of this compound has led to the elevated concentrations of triclosan in wastewater, wastewater treatment plants (WWTPs) and receiving waters. Removal of triclosan and formation of triclosan-methyl was investigated in activated sludge from a standard activated sludge WWTP equipped with enhanced biological phosphorus removal. The removal was found to occur mainly under aerobic conditions while under anoxic (nitrate reducing) and anaerobic conditions rather low removal rates were determined. In a laboratory-scale activated sludge reactor 75% of the triclosan was removed under aerobic conditions within 150 h, while no removal was observed under anaerobic or anoxic conditions. One percent of the triclosan was converted to triclosan-methyl under aerobic conditions, less under anoxic (nitrate reducing) and none under anaerobic conditions.     

Utilization of municipal solid waste incineration fly ash for sulfoaluminate cement clinker production

The feasibility of partially substituting raw materials with municipal solid waste incineration (MSWI) fly ash in sulfoaluminate cement (SAC) clinker production was investigated by X-ray diffraction (XRD), compressive strength and free expansion ratio testing. Three different leaching tests were used to assess the environmental impact of the produced material. Experimental results show that the replacement of MSWI fly ash could be taken up to 30% in the raw mixes. The good quality SAC clinkers are obtained by controlling the compositional parameters at alkalinity modulus (C(m)) around 1.05, alumina-sulfur ratio (P) around 2.5, alumina-silica ratio (N) around 2.0~3.0 and firing the raw mixes at 1250 °C for 2h. The compressive strengths of SAC are high in early age while that develop slowly in later age. Results also show that the expansive properties of SAC are strongly depended on the gypsum content. Leaching studies of toxic elements in the hydrated SAC-based system reveal that all the investigated elements are well bounded in the clinker minerals or immobilized by the hydration products. Although some limited positive results indicate that the SAC prepared from MSWI fly ash would present no immediate thread to the environment, the long-term toxicity leaching behavior needs to be further studied.     

3种水培植物根系分泌的有机酸对氮循环菌的影响

通过收集水培吊兰、空心菜和水芹的根系分泌物,采用液相色谱分析了其中有机酸的种类和含量;并研究了根系分泌物中的有机酸对氮循环菌的影响。结果表明3,种植物根系分泌物中的有机酸对氨化细菌和反硝化细菌的生长具有促进作用,对亚硝化细菌和硝化细菌的生长具有抑制作用。     

泡沫活性炭的制备及其对丙酮的吸附性能研究

以中间相沥青和原煤为原料,在高温高压下发泡成型,经过高温炭化和水蒸气活化后制得了比表面积为672m2/g、中孔发达的泡沫状成型活性炭(MACFoam).该成型活性炭中含有大量的微米级孔道并具有良好的透气性,可以作为气流通道.由其所装填的吸附床层对丙酮的吸附行为与颗粒活性炭相似,可以使用Yoon-Nelson方程对实验穿...     

水解酸化-气浮-厌氧-好氧处理苎麻脱胶废水

江西瑞昌某苎麻公司产生大城污染严重的苎麻废水。废水处理规模300m^3／d。采用水解酸化-气浮-厌氧-好氧为主体的处理工艺,出水达到GB8978—96一级排放标准．该工艺具有耐冲击负荷、运行稳定、易于管理和运行费用低等优点。     

黄土丘陵区不同水体中氢氧同位素特征及相互关系

为了研究典型黄土丘陵区不同水体氢氧同位素特征及水体间补给转化关系,合理利用干旱半干旱区水资源,通过野外采集2019年6月至11月延安市安塞墩山周围降水、河水、地下水和土壤水样品,运用同位素示踪技术,结合混合模型探索研究区不同水体氢氧同位素特征及水循环转化关系.结果表明:河水、地下水较土壤水富集氢氧同位素;各水体D和18...     

从中外对比看中国生态旅游发展存在的问题

国外生态旅游的思想起源于20世纪60年代,80年代传入中国并由政府推动发展起来的.本文从生态旅游的起源谈起,梳理了国内外对生态旅游概念的理解,分析了国内外发展生态旅游的产生背景及发展现状,指出当前我国生态旅游发展存在3个方面的主要问题,最后从5个方面提出了解决对策.     

地形和季节变化对有机氯农药分布特征的影响——以四川省成都经济区为例

在成都经济区典型地貌单元（平原区和丘陵区）采集春季和秋季样品,共计52件农作物样品和100件土壤样品,通过美国EPA8080A方法测试样品中有机氯农药含量,以研究不同地貌单元不同季节有机氯农药污染分布特征。结果表明：土壤中DDT含量高于HCH含量;平原区绵竹市土壤中有机氯农药含量高于丘陵区盐亭县土壤有机氯农药含量;在平原区的绵竹市,秋季采集的土壤中有机氯农药含量高于春季样品中有机氯农药含量;在丘陵区的盐亭县,春季采集的土壤有机氯农药含量高于秋季样品中含量。农作物中有机氯农药的检出率较高,各种作物浓度均未超标,但对人们健康具有潜在危害。油脂含量高的粮食作物中有机氯农药含量高于叶类蔬菜和果实类蔬菜中有机氯农药的含量。地貌类型、土壤有机质含量以及有机氯农药施用是造成两个地区春、秋季土壤含量特征不同的主要原因,而植物的吸收方式、OCP的物理化学性质是影响农作物中OCP含量不同的主要因素.     

好氧颗粒污泥生物吸附酸性红B的试验研究

为了考察灭活好氧颗粒污泥(Aembic cranular Siudge,AGS)生物吸附偶氮染料酸性红B(Acid Red B,ARR)的能力,对初始pH值、吸附剂用量、ARB初始浓度以及NaCl浓度等条件对生物吸附的影响进行了批式试验.结果表明,初始pH值是影响ARB生物吸附的最苇要因素,最佳pH值为2.0.平衡吸附量随ARB初始浓度的增加而增加,随吸附荆浓度和NaCl浓度的增加而减少.通过傅立叶红外光谱分析得出AGS上的化学官能团(如胺基、羧基和羟基等)是吸附酸性红B的活性位置.研究表明,灭活ACS可以作为一种低成本的生物吸附剂来去除偶氮染料ARB及类似染料.