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541.
MARKKU T. KUITUNEN JOHANNA VILJANEN ESKO ROSSI ARTO STENROOS 《Environmental management》2003,31(1):0079-0085
The impact of dense traffic on the breeding success in pied flycatchers (Ficedula hypoleuca) was studied using roadside nest-boxes. Nest site selection and breeding success of flycatchers were observed in relation
to the distance from the road. The number of occupied territories was no higher closer to the road than it was deeper inside
the forest. The distance to the road had no effect on the laying date, clutch size, or brood size. However, nests closer to
the road were more likely to fail at the chick stage. The number of broods that were closer to roads and were lost completely
was significantly higher than those further away. As a consequence, the number of fledglings per breeding attempt decreased
closer to roads. The nestlings typically died as older chicks when the parent birds were providing them with maximum quantities
of food. A possible reason for the declining reproductive success was the traffic-related mortality of parent birds, as weather
conditions were not especially adverse for raising healthy offspring. 相似文献
542.
目的 探究 A517 海工钢在海洋全浸区环境下的腐蚀机理。方法 通过模拟海洋全浸区腐蚀环境,利用失重法、SEM、EDS、XRD、电化学等测试技术,分析A517钢的腐蚀行为历程,并探讨其在全浸区的腐蚀机理。结果A517钢在厚度方向上的最大电位差为 13 mV,小于发生电偶腐蚀的最小电位差50mV,说明材料在厚度方向上的腐蚀敏感性一致。随浸泡时间的延长,腐蚀质量损失量逐渐增加,平均腐蚀速率先降低、后升高、最后趋于稳定,腐蚀速率约为 0.127 mm/a。结论 腐蚀动力初期主要是由溶解氧的极限扩散控制,后期则是腐蚀产物的氧化还原电荷转移控制。腐蚀首先在 Al2O3、MgO 等夹杂物处萌生扩展,腐蚀产物出现明显的分层现象,外锈层主要是疏松易脱落的γ-FeOOH,内锈层主要是致密均匀的 Fe3O4,同时锈层中还检测到了β-FeOOH和α-FeOOH的存在。锈层中存在大量微裂纹,削弱了产物膜的保护作用,促进了腐蚀的进行。 相似文献
543.
544.
The sperm cell toxicity test with Paracentrotus lividus is widely used in Italy to assess the quality of complex aqueous matrices, but at present there is a shortage of standardized methodologies for the bioassay performance. In this work several critical points were considered, in order to verify the reliability of this bioassay and to improve its standardization.In particular, we have studied the differences in EC50 values at different sperm: egg ratios and with different quantities of gametes; the influence of sperm and eggs on fertilization rate and the influence of different recipients materials (plastic or glass). At the same time, it was evaluated if the obtained EC50 values were in accordance with those reported in literature.Experiments performed yielded EC50 values for copper ranging from 16.54 μ g/l to 69.59 μ g/l, with a total mean value ± SD of 39.79 μ g/l ± 11.17. These data fit with those found in literature for other echinoid species. According to the same authors, poor fertilization was probably due to the effects on sperm and not on eggs, and moreover the linear regression analysis performed on each experiment suggested that the best amount of eggs to use in the test was 1000.Results from the comparison between the performance of the test in plastic or glass tubes showed an higher success in fertilization rate using borosilicate glass tubes. 相似文献
545.
546.
稳定塘的水力模型对于稳定塘的设计、运行和评价具有重要作用。该文在对稳定塘的各种水力模型分析的基础上,利用试验数据,对各种水力模型进行了识别与评价。结果表明:稳定塘的水力流态接近于完全混合态,基本上相当于2个或3个完全混合反应器的串联,无量纲扩散数d一般介于0.1~0.5之间。 相似文献
547.
在分析现行环保投资体制改革进程的基础上,提出了深化我国环保投资体制改革的总体目标、基本内容及其外部条件。为了保证足够的环保投入,提高环保投资效益,当前,政府部门应抓住改革的有利时机,稳妥、适时和有重点地推进环保投资体制的深化改革。 相似文献
548.
通过对近年深圳市区域环境噪声及道路交通噪声的监测数据分析,发现深圳市交通声源是长期影响城市区域环境噪声的主要因素,其根源在于城市机动车辆增加迅速,路网过密,而配套设施跟不上,造成对城区域环境噪声污染相对集中,城区声环境日趋恶化。 相似文献
549.
Forests managed through peoples' participation can help to achieve a number of sustainable development goals (SDGs). This paper, drawing data from four participatory forest management (PFM) projects in south-eastern Bangladesh, explored: (a) the factors that influenced the outcomes of PFM; and (b) contribution of PFM towards achieving selected SDGs. The research used observation, semi-structured household interviews, group discussions, vegetation survey and Ostromʼs design principles for data collection, Divergent forest conditions and factors in four PFM sites have had differential contribution to SDGs. Heterogeneity of user groups, insufficient coordination, absence of motivation, and land tenure conflicts had affected the attainment of SDGs. The PFM helped to achieve 9–11 SDGs comprising poverty reduction (Goal 1), improving food security (Goal 2), maintaining health and well-being (Goal 3), enhancing childrensʼ education (Goal 4), fair access to jobs and committees (Goals 5 and 10), sources of clean drinking water (Goal 6), affordable energy for cooking (Goal 7), increased household economy (Goal 8), climate change through carbon sequestration (Goal 13), forest conservation (Goal 15), and partnerships with relevant institutions (Goal 16). In order to achieve SDGs, PFM could be viewed as an integral part of government development strategies, which needs sectoral coordination and integration of relevant policies. 相似文献
550.
山东省经济结构的失衡水平:测度和比较 总被引:1,自引:0,他引:1
山东省是中国经济发展最快的省区之一,但随着经济增长的不断推进所积累的矛盾和失衡水平也逐渐提高,经济发展的可持续性日趋降低。为考察山东省经济发展的现状,明确山东省经济结构中存在的问题,该文拟根据文献[1]的方法,构建省域经济结构失衡程度指标体系。考虑到省域经济的特殊性,确定了包括产业结构、投资消费结构、金融结构、省内经济结构和国际收支结构5大类共17个指标作为基本指标体系,对近10年以来山东省经济结构失衡程度进行了测试,并且利用相同的指标体系对广东、江苏、浙江等东部代表性省区以及全国的整体结构失衡水平进行了测度和比较分析,明确了山东省经济结构失衡的绝对水平和相对水平。结果表明:山东省经济结构失衡现象较为突出,经济发展的可持续性日趋降低。本文建议山东省加快第三产业发展,理顺投资与消费的关系,提高国民经济中消费所占比重,平衡省内各市际间经济发展水平才能真正缓解经济结构失衡状况,增强可持续发展的动力。 相似文献