凝聚度——描述与测度社会生态系统抗干扰能力的一种新特性

研究一个网络系统抵抗干扰的能力,系统科学里有＂鲁棒性＂的概念,社会—生态系统里用＂脆弱性＂、＂恢复性＂和＂适应性＂等概念.这些已有的概念是否已经全面地描述了系统抵抗干扰的能力呢？在综合灾害风险管理的实践中,整个社会凝心聚力,行动协调一致,往往发挥着至关重要的决定性作用.然而,现有学术研究中所用到的各种系统属性,都不能很好表述一个系统凝心聚力的能力或水平.鉴于此,本文提出一种全新的网络系统属性：网络凝聚度（consilience degree）,专门用以度量一个如社会—生态系统一样行为的网络系统凝心聚力,行动协调一致,以抵抗干扰的能力.网络凝聚度实际上是一种更具普遍意义的＂联结度＂.它可以象联结度一样,派生发展出一系列的系统新属性和网络新模型,从而形成一个研究复杂系统的新的理论体系.本文将重点阐述这个体系的雏型.理论分析和仿真研究都证明：本文所提出的网络凝聚度是现有各种系统属性所无法涵盖或替代的,是研究现实复杂系统所必需的新理论工具.     

A kernel-driven model of effective directional emissivity fornon-isothermal surfaces

Land surface temperature (LST) is a key geophysical parameter that reflects the combined effects of land surface energy and radiation balance. Remote sensing of LST, however, requires understanding the directional patterns of thermal emission from heterogeneous land surfaces. Recently, semi-empirical, linear, kernel-driven models have been successfully used to describe observed directional patterns of land surface reflectance. Following a similar methodology and based on a recent model of the physics of directional thermal emission from heterogeneous land surfaces, a kernel-driven semi-empirical model for thermal emission is developed using three kernels: (i) an isotropic kernel, corresponding to the gray-body component in a heterogeneous pixel; (ii) a two-layer canopy kernel, derived from a previous conceptual model; and (iii) a geometric optical kernel that accounts for the fact that sunlit parts are hotter than shaded parts in a pixel. The three-kernel model fits 1997 airborne directional thermal brightness data over Avignon, France, very well.     

手机诉讼面临科学检验

关于手机会增加脑癌发生机率的证据在科学法庭上并不是一帆风顺 ;在法律法庭上 ,它会被认可吗 ?     

Physiology: does gut hormone PYY3-36 decrease food intake in rodents?

Batterham et al. report that the gut peptide hormone PYY3-36 decreases food intake and body-weight gain in rodents, a discovery that has been heralded as potentially offering a new therapy for obesity. However, we have been unable to replicate their results. Although the reasons for this discrepancy remain undetermined, an effective anti-obesity drug ultimately must produce its effects across a range of situations. The fact that the findings of Batterham et al. cannot easily be replicated calls into question the potential value of an anti-obesity approach that is based on administration of PYY3-36.     

重建海地：太阳下的岛屿

也许谈论重建海地的机遇对这个尚未从地震阴霾中摆脱的国家来说有点冷酷无情。但我们不能任由它重新陷入悲剧。重建机遇之一是改善海地的能源基础设施。目前，海地因缺少化石燃料，每年需耗资500万美元进口。     

对辊式粉碎机和锤片式粉碎机的评价

对于大多数商业性饲料厂,粉碎能耗仅次于制粒,甚至更大.这就是为什么饲料厂经理在设计一个新饲料厂或修复旧设备时,特别注重于各种减小粒度的方法.节能将是新方法的重点.人们虽已习惯使用锤式粉碎机“担负”饲料厂的粉碎任务,但必须重新评价饲料工业的新变化.当代饲料消费者更加注意饲料     

在中国实行库存系统的设想

本文讨论发展中国家建立现代化库存和物资管理系统会遇到的问题。在回顾一些与现实有关的历史背景以后,提出了在较少资金和技术能力条件下逐步采用现代化库存实践的建议。     

Forest cover change and its effects on the livelihood of the dependent local people:the case of Sesheke district of Zambia

Objective--To investigate forest cover change in Masese Local Forest Reserve and its effects on the livelihoods of the dependent communities; to establish the occurrence of forest cover change in Masese Local Forest Reserve; to determine the extent of forest cover change in Masese from 1990 to 2005; to determine the tree species that have been affected by forest cover change in Masese; and to assess the effects of forest cover change on the livelihoods of the dependent communities. Methods--Interviews and questionnaire were conducted with a proportion of 36 households from Ma- ondo and 84 households from Mulimambango settlements. Scenes of landsat images of 1990, 2000, 2005 and Earth Google image for Masese were used for map analysis. Also remote sensing was used to analyze landsat images and Google image to detect forest and non-forest classes. Results and Conclu- sion-Forest cover change has adverse implication on the provision of wood forest products and non- wood forest products to the dependent local communities. The declining status of dominant Baikiaea Forest that has exploitable species for building materials and fuel wood has affected the livelihoods of the dependent local communities. There is also increased cost and shortage of fire wood and building materials due to deforestation in Masese Forest Reserve.     

束参数对离子束溅射法所淀积非晶硅电特性的影响

本文论述了用离子束溅射淀积非晶硅(a-Si)和氢化非晶硅(a-Si:H)的方法,提供了加速电压和衬底位置改变对薄膜暗电阻率的影响结果,通过有关淀积工艺条件的研究,得出了一些有用的结论。