Foliar and shoot allometry of pollarded black locust, Robinia pseudoacacia L.

Browse of multipurpose tree species such as black locust could be used to broaden grazing options, but the temporal distribution of foliage has not been adequately studied. Our objective was to determine effects of harvest date, P fertilization (0 and 600 kg ha⁻¹ yr⁻¹), and pollard height (shoots clipped at 5-, 50-, and 100-cm above ground) on foliar and shoot allometry of black locust. The experiment was conducted on a naturally regenerated 2-yr-old black locust stand (15,000 trees ha⁻¹). Basal shoot diameter and foliar mass were measured monthly in June to October 2002 and 2003. Foliar and shoot dry mass (Y) was estimated from basal shoot diameter (D) by the function Y = aD ^b , with regression explaining ≥95% of variance. Allometry of foliar mass was affected by harvest date, increasing at a greater rate with D in September than in June or July, but not by P fertilization or pollard height. Foliar mass was predicted best by month-specific equations for the June to October growth interval. Allometry of shoot dry mass was unaffected by harvest date, P fertilization, or pollard height. These equations could be used as a first approximation of foliar and shoot mass for pollarded black locust.     

河南省林种结构调整的研究

根据１９９３年省森林资源清查、森林资源消耗量及消耗结构的调查资料，以可持续发展的理论为指导，采用线性规划对我省的林种结构进行了研究。研究结果：河南省现阶段的林种结构应为：用材林∶防护林∶经济林∶薪炭林∶特用林＝３４９∶１５９∶２３７∶２１１∶４４。     

气象实时数据监控程序的设计与开发

对上海气象信息与技术支持中心而言,原先的气象信息数据监控系统由于操作复杂而需要改进.新的监控系统开发使用delphi6.0语言和多线程技术,对自动站数据、雷达和卫星数据、MICAPS压缩数据和MICAPS解压数据这四类气象实时数据进行监控,以一体化的方式展现所有重要的监控信息,提高了工作效率.     

喀什市土地资源优化配置研究

以新疆维吾尔自治区喀什市作为研究对象,以2009年喀什市土地结构利用数据作为基期数据,借助线性规划方法对喀什市土地资源进行优化配置.通过对喀什市土地利用现状的分析,并结合当地社会经济发展特点以及相关规划调控指标,预测2020年喀什市土地利用结构优化数据,以使得喀什市土地综合利用效益达到最大.     

Spatial optimization by simulated annealing and linear programming

Forest management planning comprises selection among treatment alternatives in management units. A traditional linear programming (LP) approach may effectively account for a profit maximization objective combined with sustainability constraints, e.g. on the temporal distribution of harvest volume flows, cash‐flow, and net present value development, but it fails to account for spatial constraints, especially those associated with final felling. By applying a simulated annealing adjacency model based on net present value maximization and combined with an LP consequence computation model, it is possible to delineate optimal strategies of final felling scheduling. Evaluation is made of the trade‐off between (1) the incremental cost (determined by use of the LP model) of an optimal adjacency model solution, and (2) the potential damage cost resulting from adjacency characteristics such as windthrow and bark injuries. The decision support system may contribute significantly to reduce damage costs and may improve the reliability of forest management planning.     

Prematurity and Dysmaturity Are Associated With Reduced Height and Shorter Distal Limb Length in Horses

The long-term effects of gestational immaturity in the premature (defined as < 320 days gestation) and dysmature (normal term but showing some signs of prematurity) foal have not been thoroughly investigated. Studies have reported that a high percentage of gestationally immature foals with related orthopedic issues such as incomplete ossification may fail to fulfill their intended athletic purpose, particularly in Thoroughbred racing. In humans, premature birth is associated with shorter stature at maturity and variations in anatomical ratios, linked to alterations in metabolism and timing of physeal closure in the long bones. We hypothesized that gestational immaturity in horses might similarly be associated with reduced height and different anatomical ratios at maturity. In this preliminary study, the skeletal ratios of horses with a history of gestational immaturity, identified through veterinary and breeder records, were compared with those of unaffected, closely related horses (i.e., sire, dam, sibling). External measurements were taken from conformation photographs of cases (n = 19) and related horses (n = 28), and these were then combined into indices to evaluate and compare metric properties of conformation. A principal component analysis showed that the first two principal components account for 43.8% of the total conformational variation of the horses’ external features, separating horses with a rectangular conformation (body length > height at the withers), from those that are more square (body length = height at the withers). Varimax rotation of PC1 and analysis of different gestational groups showed a significant effect of gestational immaturity (P = .001), with the premature group being more affected than the dysmature group (P = .009, P = .012). Mean values for the four dominant indices showed that these groups have significantly lower distal limb to body length relationships than controls. The observed differences suggest that gestational immaturity may affect anatomical ratios at maturity, which, in combination with orthopedic issues arising from incomplete ossification, may have a further impact on long-term athletic potential.     

网络课件在C程序设计语言教学中的应用

传统的黑白教学方法存在着一些弊端，导致学习效率降低、资源浪费。网络教学这种新型教育模式不仅大大提高了学习效率，而且很大程度地发挥了教育资源的作用。本文以C程序设计语言为例，阐述了制作网络课件的关键技术和实现技巧。     

一种改进的基因表达式编程方法及应用

基因表达式编程(GEP)是基于遗传算法和遗传编程的具有更强数据处理和知识发现的进化算法。介绍了传统GEP算法的基本原理和关键技术,针对求解问题时传统GEP存在未成熟收敛和进化后期收敛速度慢等问题,提出了GEP算法的改进方法,并将改进算法应用于函数发现问题中。与传统GEP算法的对比试验表明改进的GEP算法具有更好的求解能力和更高的性能。     

APPLICATION OF A CONVEX NETWORK FLOW PROGRAMMING TO THE ECONOMIC POWER DISPATCH

Analyses the characteristics of convex network flow programming of the economic power dispatch with security and presents a rapid algorithm. The numerical examples are given to demonstrate the effectiveness of the algorithm.