Long-term global earth surface ultraviolet radiation exposure derived from ISCCP and TOMS satellite measurements

A long-term (1983–2000) global dataset of Earth’s surface daily-integrated UV exposure was developed from a combination of ISCCP-D1 3 h reflectance measurements (in order to resolve the diurnal variation of cloud conditions) and TOMS total ozone amount. The inversion algorithm developed in our previous study was employed with modifications addressing the conversion of visible reflectance to UV albedo and narrowband UV albedo to broadband albedo over the range of 280–400 nm. Validation of the product was carried out using ground-based measurements at six stations. In general, good agreements between the estimated and measured daily UV exposure are found at most stations; the relative mean and root mean square (RMS) difference varies from 3 to 14% and from 20 to 45%, respectively. Among the stations, San Diego has a fairly low mean difference (9%) and the lowest RMS difference (33%), owing to the prevailing clear sky or uniform cloud cover condition. The RMS difference increases with cloud amount, which is largely caused by mismatch between satellite and ground-based measurements. The effect of diurnal variation in atmospheric opacity associated primarily with cloud on the estimation of daily erythemal UV doses is investigated with both ground-based measurements and ISCCP-D1 data. It is found that daily erythemal UV doses estimated from only a noontime satellite “snapshot” may incur errors larger than 20%, which may be reduced for long-term averaging.     

Arthropod assemblages in vegetative vs. humic portions of epiphyte mats in a neotropical cloud forest

Epiphyte mats (contiguous pieces of live and dead epiphytes perched upon branches of trees) are a conspicuous component of tropical cloud forests and harbor diverse meso- and microarthropod communities. We investigated differences in arthropod assemblage structure between the vegetative (green) and humic (brown) portions of epiphyte mats in a lower montane forest in Monteverde, Costa Rica. Because of qualitative differences between the two substrates, we hypothesized that they would support different arthropod communities and that variation in community parameters would be linked to the quantity of brown material present in a mat sample. The green fraction contained twice as many individuals and species per gram dry mass than the brown fraction. Morphospecies composition was very similar between green and brown portions, but the relative abundance of several taxa differed significantly between the substrates. Contrary to our prediction, total arthropod abundance and richness in a sample were not correlated with the proportion of brown material present. In laboratory trials, the most common morphospecies of oribatid mite in this system showed a preference for brown substrates.     

Species diversity and habitat fragmentation: frogs in a tropical montane landscape in Mexico

We evaluate the alpha (within patch species richness), beta (spatial turnover among patches) and gamma (landscape) diversity of frogs in a tropical montane cloud forest (TMCF) in central Veracruz, Mexico in order to assess (1) the influence of forest fragmentation on frog assemblages, (2) the importance to diversity of the various elements of the landscape matrix, including the shaded coffee plantations and cattle pastures that surround TMCF and (3) to identify the frog guilds most affected by habitat transformation. We sampled ten sites between May 1998 and November 2000: five TMCF fragments and five anthropogenic habitats. For the entire landscape, we registered 21 species belonging to six families. 100% of these were found in the TMCF fragments and 62% in the surrounding mosaic of anthropogenic habitats. Gamma diversity (γ) is determined to a greater extent by species exchange (β) than by local species richness (α). Elevational variation, the degree of conservation of the vegetation canopy and fragment size appear to determine the species diversity of this landscape. Large species, terrestrial species, those whose eggs develop outside water, and those whose larvae develop in the water seemed to be most affected by habitat transformation. On its own, even the largest and most species-rich cloud forest fragment is not capable of preserving the current anuran diversity. Neither are the shaded coffee plantations that are interspersed among and link the patches of TMCF. However together they form a diverse system of habitats crucial to species conservation in this landscape.     

基于混合策略机制的人工鱼群算法

针对人工鱼群算法在处理多峰函数问题时存在一部分人工鱼处于漫无目的的随机移动、易陷入"早熟收敛"情况造成的收敛速度减慢的缺点,提出一种基于混合策略机制的人工鱼群算法。它借鉴群体位置方差的早熟判断机制,把云发生器产生的杂交和变异算子引入到该算法中,为减少算法计算量,而采用耗散的人工鱼群算法结构。仿真实验表明,该算法比只有一个适应值的人工鱼群算法具有更快的收敛速度,且具有很强的避免局部极小能力,其性能远远优于单一优化方法。     

云计算与移动数字图书馆

移动数字图书馆作为图书馆在信息技术变革中推出的新服务模式,无疑会受到云计算技术的影响。通过分析云计算的特征和应用形式,提出移动数字图书馆应用云计算的三种模式,即基础设施即服务（IAAS）、软件即服务（SAAS）和平台即服务（PAAS）。     

构建财经科技文献资源“云”平台

探讨了构建财经科技文献资源"云"平台的具体措施,须订立统一的接口和标准,联合各类数据机构,才能建立广泛的信息资源数据中心,以此实现财经科技文献资源的共建共享,为今后各级各类平台项目全面整合提供有益的探索和尝试。     

云计算在新农村信息化建设中的应用研究

目前,新农村信息化建设中依然存在着不足,尤其是农村信息化基础设施比较落后;农业信息资源共享存在一定局限性。将云计算结合到新农村信息化建设的应用中,能够解决上述存在的诸多问题,并能够为新农村信息化新的应用模式提供强大的技术支持。首先介绍了农村信息化建设和云计算技术发展的现状,在现有的农村信息化基础上利用云计算技术,采用“松散耦合模式”对现有农村信息化系统进行面向服务的封装或者改造,搭建新农村信息化云基础架构,实现信息资源共享。     

基于云计算和RFID技术的农产品物流信息系统研究

以安徽舒城调研为基础,分析影响农产品物流市场发展现状和存在的问题,并提出利用云计算平台、RFID智能物流管理等先进信息技术构建农产品物流信息管理系统,进而完善农产品质量安全溯源体系,充分降低物流成本,提升农产品的质量安全档次。     

基于云计算的农业科研创新信息服务平台设计

针对传统信息技术支撑的信息服务平台存在投资成本高、信息孤岛等问题,提出基于云计算的农业科研创新信息服务平台的建设思路,分析信息技术在农业科研领域应用的相关研究工作,介绍云计算在其他行业的应用情况,设计云计算在农业信息服务领域应用的体系架构,对云计算在行业应用中的多租户技术、自动服务组合技术等进行介绍,提出一种面向行业应用的云计算体系架构,对云计算在行业的应用推广具有借鉴意义。     

基于云课堂的混合式教学法在实践课程教学的研究

随着信息技术的发展,以及传统教学模式下学生学习现状的不容乐观,世界范围内多种新教改模式相继出现。其中以云课堂为基础的混合式教学法,迅速扩展到教育的各个领域。本文研究了云课堂的混合式教学法在我校药物分析与检验技术课程中的实践应用,从研究背景、研究的方法目标及实践教学设计等方面进行了阐述。