大气中过氧化氢的生成、污染特征及其影响因素

过氧化氢(H₂O₂)是自由基的源和汇,是对流层大气中重要的氧化剂. 采用文献研究法对1990年以来H₂O₂的文献进行搜集整理,对其生成途径、污染特征及其影响因素进行了研究. 结果表明:H₂O₂在大气、云水和颗粒物中均有存在,大气中的H₂O₂主要通过O₃和甲醛光解、VOC同OH·/O₃等反应生成. 大气中φ(H₂O₂)一般在nd～8×10-9内波动,晴天φ(H₂O₂)呈早晚低、午后高的日变化特征;φ(H₂O₂)随φ(O₃)、太阳辐射和气温的增加而升高,随φ(NO_x)、φ(VOCs)和相对湿度的升高而降低;H₂O₂氧化SO₂为SO₄2-是液相化学中最重要的反应,可以导致酸沉降以及二次气溶胶浓度的升高. 在气相光化学反应中,H₂O₂/HNO₃(体积分数比)可以指示O₃生成是VOCs控制还是NO_x控制. 今后需对OH·浓度、NO₂和O₃的光解速率等影响H₂O₂关键因素开展监测研究,此外,还需对我国特殊大气环境下H₂O₂对SO₄2-生成的贡献、不同地区H₂O₂/HNO₃指示O₃生成对NO_x或VOCs敏感性等方面开展更多的研究.      

年度城市环境事件评选:方法、评析及启示

政府和民众对于城市环境事件的关注越来越高,树立典型是激励良性发展的有效手段。为了提高年度城市环境事件评选的科学性和合理性,本文提出定量和定性相结合的评选方法,包含事件收集、事件筛选、事件评定三个阶段。在此基础上,对2016年度中国城市环境保护十大事件进行了评选,无锡、贵溪、三亚、珠海的案例分别代表了水、土、气、生4个专项领域环境治理和保护的先进典型;杭州、深圳、三沙的案例分别体现了以大型赛事活动为契机开展城市综合环境整治的先进经验,以及市场化的治理手段和生态技术对于城市综合治理的重要性;上海(崇明)、重庆、鄂尔多斯(库布齐地区)代表了因地制宜的区域生态文明发展模式。通过案例分析,得出如下启示:提升环境治理成效应该兼顾责任制、市场化、民主化的管理模式创新和各种技术创新;生态环境要素应该被视为城市发展的新兴增长点;城市环境保护行为具有发展和再分配双重属性,环保行为的发展属性仍有待于继续普及,而先行城市应该借鉴典型经验,积极探索通过环境保护实现经济发展的新模式。     

Ethanol concentration in food and body condition affect foraging behavior in Egyptian fruit bats (Rousettus aegyptiacus)

Ethanol occurs in fleshy fruit as a result of sugar fermentation by both microorganisms and the plant itself; its concentration [EtOH] increases as fruit ripens. At low concentrations, ethanol is a nutrient, whereas at high concentrations, it is toxic. We hypothesized that the effects of ethanol on the foraging behavior of frugivorous vertebrates depend on its concentration in food and the body condition of the forager. We predicted that ethanol stimulates food consumption when its concentration is similar to that found in ripe fruit, whereas [EtOH] below or above that of ripe fruit has either no effect, or else deters foragers, respectively. Moreover, we expected that the amount of food ingested on a particular day of feeding influences the toxic effects of ethanol on a forager, and consequently shapes its feeding decisions on the following day. We therefore predicted that for a food-restricted forager, ethanol-rich food is of lower value than ethanol-free food. We used Egyptian fruit bats (Rousettus aegyptiacus) as a model to test our hypotheses, and found that ethanol did not increase the value of food for the bats. High [EtOH] reduced the value of food for well-fed bats. However, for food-restricted bats, there was no difference between the value of ethanol-rich and ethanol-free food. Thus, microorganisms, via their production of ethanol, may affect the patterns of feeding of seed-dispersing frugivores. However, these patterns could be modified by the body condition of the animals because they might trade-off the costs of intoxication against the value of nutrients acquired.     

改建铁路沪汉蓉通道襄樊至安康段增建第二线关于环保问题的方案选线

改建铁路沪汉蓉通道襄樊至安康段增建第二线铁路原设计增建第二线线路全长361.824km,其中Dzk67+480-D zk79+480段有12km经过武当山风景名胜区。为相应国家环境保护的号召,为了尽量减少工程建设对武当山风景名胜景区古建筑群的影响,工程在选线过程中绕避古建筑群,以隧道隐蔽工程穿过,且对原生态环境影响最小。     

The effects of colony-level selection on the social organization of honey bee (Apis mellifera L.) colonies: colony-level components of pollen hoarding

Two-way selection for quantities of stored pollen resulted in the production of high and low pollen hoarding strains of honey bees (Apis mellifera L.). Strains differed in areas of stored pollen after a single generation of selection and, by the third generation, the high strain colonies stored an average 6 times more pollen than low strain colonies. Colony-level organizational components that potentially affect pollen stores were identified that varied genetically within and between these strains. Changes occurred in several of these components, in addition to changes in the selected trait. High strain colonies had a significantly higher proportion of foragers returning with loads of pollen, however, high and low strain colonies had equal total numbers of foragers Colony rates of intake of pollen and nectar were not independent. Selection resulted in an increase in the number of pollen collectors and a decrease in the number of nectar collectors in high strain colonies, while the reciprocal relationship occurred in the low strain. High and low strain colonies also demonstrated different diurnal foraging patterns as measured by the changing proportions of returning pollen foragers. High strain colonies of generation 3 contained significantly less brood than did low strain colonies, a consequence of a constraint on colony growth resulting from a fixed nest volume and large quantities of stored pollen. These components represent selectable colony-level traits on which natural selection can act and shape the social organization of honey bee coloniesCommunicated by R.F.A. Moritz     

Experimentally elevated plasma levels of testosterone do not increase male reproductive success in blue tits

In temperate passerines, increased testosterone (T) levels during breeding mediate male aggressive and mating behaviour. If individual variability in T levels is reflected in behavioural differences during mating, males with higher T might gain higher reproductive success. This can be tested experimentally by elevating T levels. However, high exogenous T levels are known to have negative effects on male sperm production. This may reduce male fitness, particularly if sperm competition is intense. We experimentally elevated T levels in breeding blue tit males to investigate how T levels above the natural mean influence male reproductive success. Contrary to most—if not all—previous experimental manipulations of T levels in birds, we restricted the treatment with exogenous T to the time when females were fertile and T levels were naturally high in males. In blue tits, extra-pair paternity is an important component of male reproductive success, and its frequency is likely influenced by androgen-mediated behaviours such as mate attraction and aggression towards other males. Here we show that T-males were equally likely to become cuckolded and did not gain more extra-pair paternity than control males. Cuckolded T-males, however, lost more paternity than control males. We discuss the possibility that this is caused by negative effects of T treatment on sperm production.Communicated by M. Webster     

多孔陶瓷球负载纳米晶粒二氧化钛光催化剂的制备及光催化活性

以多孔陶瓷球为载体,采用溶胶-凝胶法在其表面进行纳米TiO2薄膜负载,制备了多孔陶瓷球负载纳米晶粒二氧化钛光催化剂,经X射线衍射法(XRD)等手段对其表征结果表明,复合载体经500℃焙烧后,TiO2以锐钛矿晶型存在。对催化剂降解活性艳蓝溶液的催化活性进行研究表明,催化剂在5 h内可完全降解活性艳蓝染料。     

Male tail streamer length predicts fertilization success in the North American barn swallow (Hirundo rustica erythrogaster)

In socially monogamous species, extra-pair paternity has the potential to increase the variance in male reproductive success, thereby affecting the opportunity for sexual selection on male extravagant ornamentation. In the European barn swallow (Hirundo rustica rustica), the tail streamer length is a sexually selected male ornament and an honest indicator of viability. The North American barn swallow (Hirundo rustica erythrogaster) also shows sexual dimorphism in tail streamer length, but whether this trait holds the same signalling function in this subspecies is a controversial issue, and the available literature is presently scarce. Here, we present data on paternity in the North American barn swallow, including a complete sampling of extra-pair sires in four colonies. We analysed how extra-pair paternity affected the variance in male fertilization success and examined whether male tail streamer (i.e. the outermost tail feather) length correlated with fertilization success (n=86 males). Extra-pair paternity constituted 31% of all offspring and significantly increased the variance in male fertilization success. The number of offspring sired by extra-pair males accounted for almost half of the total variance in male fertilization success. Males with naturally long tail streamers had a higher fertilization success than males with shorter tail streamers, and this pattern was mainly caused by a higher extra-pair success for males with long tail streamers. Males with long tail streamers also paired with early breeding females in prime body condition. These results are consistent with the idea that there is directional sexual selection on male tail streamer length, possibly mediated through male extra-pair mating success or the timing of breeding onset.     

Patterns of fluctuating asymmetry in beetle horns: an experimental examination of the honest signalling hypothesis

Recent theoretical arguments have claimed that negative relationships between the size and symmetry of secondary sexual traits are indicative of honest signalling of male quality. The patterns of fluctuating asymmetry in beetle horns have been proposed to support the honest signalling hypothesis. Here we examine three assumptions of the hypothesis, (1) that traits are costly to produce; (2) the levels of fluctuating asymmetry are indicative of stress imposed during development; and (3) that males with larger traits should have more symmetrical traits, using the horned beetle, Onthophagus taurus. Experimental manipulations of brood mass were used to manipulate horn size and asymmetry. The development of horns was found to be environmentally determined and costly in terms of delayed development and increased risk of pre-adult mortality. Decreasing resource availability increased relative horn asymmetry. However, horn height was positively related to absolute horn asymmetry. While the results do support the hypothesis that sexual selection on secondary sexual traits should increase levels of fluctuating asymmetry, they provide no support for the notion that the patterns of asymmetry honestly signal male quality. Horns are used in disputes between males and may be indicative of male parental investment. Thus, we conclude that while horn size may be an indication of male quality, the patterns of fluctuating asymmetry are not. Received: 16 December 1996 / Accepted after revision: 5 May 1997     

Sexual ornamentation,condition, and immune defence in the house sparrow Passer domesticus

Female mate preferences for extreme male ornaments may arise and be maintained because males signal their ability to raise an immune defence against parasites by the size of their ornaments. The bursa of Fabricius is an organ involved in antibody synthesis in young birds, but regresses before sexual maturity. The relationship between badge size, condition, and immune defence was investigated in male house sparrows, Passer domesticus, which have a bib of black feathers under their beak, a secondary sexual character currently subject to a directional female mate preference. The size of the bursa of Fabricius decreased during the first year of life in house sparrows. Males with large secondary sexual characters had a smaller bursa than males with small badges. Individuals with a large directional asymmetry in relative testis size had a larger bursa. The abundance of one parasite (a mallophagan) was positively related to bursa size. There was a positive relationship between relative volume of bursa of Fabricius and the number of fault bars on feathers, which is a measure of body condition. These results suggest that males with large badges have lower current levels of immune response than males with small badges, and that males in good body condition, as evidenced from the absence of fault bars, had a relatively small bursa of Fabricius. Received: 6 October 1995/Accepted after revision: 2 June 1996