Street trees and rural conspecifics: Will long-lived trees reach full size in urban conditions?

Urban conditions are known to affect tree growth, but not all trees respond similarly to presumed stress. I test a hypothesis that successional status of hardwood tree species, rather than taxon, will differentially affect tree size relative to age, in forest versus street plantings. In central Ohio, USA, samples (N = 230) representing 15 native tree species were matched for size between rural woodlot and city street-side conditions. Their girth was measured and their age determined by a count of annual growth rings. Age and size data were analyzed by a general linear model. Most urban trees had smaller trunk diameters than rural conspecifics of the same age. However, trees of early and mid-successional ecologies, despite smaller girth, showed no reduction in growth rate over time. Late successional species appeared to be affected by proximity to impervious areas, showing reduced growth rates, and by inference,reduced ultimate size.     

发电-吸收式制冷联合装置循环的分析

对用汽轮机抽汽供热给吸收式制冷机组进行空调的蒸汽动力装置作热力学第二定律分析表明，这种既发电又供热制冷的联合装置比单发电动力装置和单供热制冷的锅炉能更有效地利用燃料能量。     

昆明市斗南村花卉生产的现状及产业化发展的对策

云南省昆明市呈贡县斗南村曾是中国千万个农村中非常普通的一个村,但如今它却以欣欣向荣的发展态势引起了各方面的关注。文章主要是在对斗南村花卉产业化经营调查的基础上,分析其经验与不足,并对其存在的问题做一些对策性研究。     

宋代墓木盗伐与保护观念探析

自古以来，人们就有在墓地种植树木的传统。在今存最早的完整成文法《唐律疏议》中，盗伐他人墓木就已写入刑法。至于宋代，有关墓木的政令以及墓木纠纷事件大量涌现，究其原因，主要在于宋代林木资源的减少、环境保护意识的加强，更为重要的则是墓木的文化象征义所致，它不仅是宋人维护宗族制度的重要纽带，体现了敬祖、爱宗之情，也关乎儒家“慎终追远”信仰所形成的终极关怀，此具体表现在两宋时期风水术中“生气”“遗体受荫”等观念盛行所形成的文化心理。     

论“空中”南水北调——南方、东北植树造林是解决华北水荒的最佳途径

森林不仅对森林所处流域内降水具有较大影响,而且对流域外特定地区的降水也具有较大影响。文章从实证的角度,论证了华北干旱与南方、东北、内蒙森林大面积减少有关。缓解华北水荒,在南方、东北、内蒙植树造林是一个效益较好的方案。     

火力发电厂及变电所电缆防火阻燃措施

介绍了火力发电厂及变电所电缆防火阻燃措施的发展状况,对电缆防火阻燃使用的材料及具体的防火阻燃措施进行了总结,并列举了典型的施工图。     

从我国已成为世界工厂之说论中国制造业再造

目前世界各国都认为我国真的在成为全球制造中心。这仅是看到我们制造业产品的数量,并没有注意到我们的产品在质量和档次上同发达国家的差距。而且我国制造业大量是来料加工,突出表现在电子工业,许多产品的核心技术和知识产权并不掌握在我们手里,因此附加值很低。我国已开始了向制造业大国的起步,但离制造业强国的距离还相当长。只有努力对我国制造业实施再造,这才是我国工业化面临的基本任务。     

忽思慧《饮膳正要》不明名物再考释

《饮膳正要》是蒙元宫廷饮食谱 ,具有较高的史料价值。从中可以透视元代蒙古、回回、畏兀儿等民族的饮食习惯 ,及其对中原汉地的影响和相互交流的文化走向 ,并着重对必思答、莳萝、哈昔泥、马思答吉等不明名物作了考释     

Significance and impotence: towards a balanced view of the null and the alternative hypotheses in marker selection for plant breeding

Summary.  The isolation of DNA markers that are linked to interesting genes helps plant breeders to select parent plants that transmit useful traits to future generations. Such 'marker-assisted breeding and selection' heavily leans on statistical testing of associations between markers and a well-chosen trait. Statistical association analysis is guided by classical p -values or the false discovery rate and thus relies predominantly on the null hypothesis. The main concern of plant breeders, however, is to avoid missing an important alternative. To judge evidence from this perspective, we complement the traditional p -value with a one-sided 'alternative p -value' which summarizes evidence against a target alternative in the direction of the null hypothesis. This p -value measures 'impotence' as opposed to significance: how likely is it to observe an outcome as extreme as or more extreme than the one that was observed when data stem from the alternative? We show how a graphical inspection of both p -values can guide marker selection when the null and the alternative hypotheses have a comparable importance. We derive formal decision tools with balanced properties yielding different rejection regions for different markers. We apply our approach to study rye-grass plants.     

从南京下关电厂看燃煤电厂的环境保护问题

南京下关电厂作为国内首座城市环保示范厂 ,努力适应当前环保形势 ,在扩建过程中进行了环境保护方面的尝试。本文着重介绍下关电厂在实现环境保护过程中的具体做法 ,为今后燃煤电厂的改造及扩建提供一些参考。