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.     

莱茵鹅15项血清生化指标的测定及分析

为了更有效地保护和利用莱茵鹅的优良基因,对北方种鹅场和双鸭山种鹅场的莱茵鹅血清进行了15项生化指标的测定及分析。结果表明:北方种鹅场和双鸭山种鹅场莱茵鹅血清三酰甘油、肌酐、直接胆红素、氯、镁、尿素氮、白蛋白和钙等血清生化指标之间的差异达到了极显著水平(P<0.01);血清总蛋白和总胆红素之间的差异达到了显著水平(P<0.05);而葡萄糖、高密度脂蛋白胆固醇、总胆固醇、无机磷和尿酸含量之间差异不显著(P>0.05)。研究还初步建立了莱茵鹅15项血清生化指标的参考值及参考范围。     

陆地棉对黄萎病抗性的分子标记研究

 利用陆地棉标准系TM-1和常抗棉2个陆地棉品种杂交并自交,获得109个F₂单株及F_2:3家系为作图群体,以SSR、RAPD和SRAP 3种分子标记进行抗黄萎病性状的分子标记筛选。结果从1611对(条)引物中仅筛选到70对(条)多态性引物,获得75个多态性位点并进行标记间的连锁性分析。75个标记构建了一个包括15个连锁群,全长535 cM的陆地棉品种间分子标记遗传连锁图,标记间平均距离为11.15 cM,有27个标记不能进入任何连锁群。连锁群的标记数最少2个,最多6个;长度从1.0 cM到92.7 cM不等。对其F_2:3家系的成株期抗黄萎病性状即平均病情指数的分布进行分析,显示其呈正态分布,进一步说明陆地棉对黄萎病的抗性为数量遗传;单标记分析及复合区间作图,检测出与抗黄萎病性相关的3个QTL,分别位于第3、5、6连锁群上,贡献率分别为14.15%、3.45%和18.78%。另外,对该群体生长过程中黄萎病不同发病高峰期的病情也进行了分析。     

单纯形—正反步长优化方法（SSPSS）及其在农业上的应用

本文提出了一种新的多变量有约束非线性函数的寻优方法——单纯形一正反步长法(SSPSS)。文中详细阐述了该方法的搜索策略和具体步骤。同时,通过实例比较了相对步长模拟法的优点。     

Reproduction and Lactational Performance of Cattle in a Smallholder Dairy System in Zimbabwe

A study was conducted in two adjacent locations. Nharira (communal) and Lancashire (small-scale commercial) farming areas in Zimbabwe to characterize the breeds and evaluate the reproductive and lactation performance of dairy cattle under smallholder management. The types of cows identified were Friesian, Jersey and Red Dane, and an indigenous Sanga breed called the Mashona and its crossbreds. Both sectors used more exotic and crossbred cows than indigenous cows. The mean monthly weights of the dairy cows were higher in Lancashire than in Nharira and the calving intervals were longer in Nharira than in Lancashire. The mean age at first calving was higher and the mean total lactation yields were greater in Nharira than in Lancashire, but the mean 305-day lactation yields were not significantly different. The mean lactation lengths were longer for the cows from Nharira. It was concluded that the reproductive and lactation performances were low. The calving intervals were extended, probably owing to suboptimal nutrition and heat stress, particularly during the dry season, and to poor management practices, such as delayed mating due to the poor availability of bulls.     

Dairy Production and Reproduction by Crosses of Holstein,Jersey or Brown Swiss Sires with Holstein-Friesian/Gir Dams

The performance was compared of cows sired by Holstein, Jersey or Brown Swiss bulls out of Holstein-Friesian×Gir dams of 1/2 to 3/4 Holstein-Friesian content. The animals were kept in a single herd under the same management. The data were analysed by least-squares techniques under a model that included the fixed effects of breed of sire, Bos taurus fraction of the dam, parity, year and season of calving, and a random cow effect. Based on 480 observations, the milk yields per lactation for the Holstein, Jersey and Brown Swiss sired groups were 2821±163, 2320±61 and 2418±119 kg, respectively. The corresponding means for fat yield per lactation were 96.9±6.6, 86.8±2.5 and 92.8±4.8 kg; for protein yield per lactation were 85.3±5.1, 71.3±1.9 and 76.3±3.7 kg; for lactation length, 339±18, 283±7 and 313±14 days for fat percentage, 3.37±0.10, 3.73±0.04 and 3.77±0.07%; and for protein percentage, 3.02±0.05, 3.10±0.02 and 3.16±0.04%. The respective calving intervals were 487±24, 408±11 and 461±245 days. The yields of milk and protein per day of calving interval were similar in the Jersey and Holstein sired groups, while the former had higher yields of fat, implying that production economics might favour the smaller Jersey crosses in production systems in which the males were not reared. Crossing with Brown Swiss did not improve performance over the Holstein sired crosses.     

Evaluating environmental impacts of the Japanese beef cow–calf system by the life cycle assessment method

The objectives of this study were to evaluate the environmental impacts of a beef cow–calf system using a life cycle assessment (LCA) method and to investigate the effects of scenarios to reduce environmental impacts on the LCA results. The functional unit was defined as one marketed beef calf, and the processes associated with the cow–calf life cycle, such as feed production, feed transport, animal management, the biological activity of the animal and the treatment of cattle waste were included in the system boundary. The present results showed that the total contributions of one beef calf throughout its life cycle to global warming, acidification, eutrophication and energy consumption were 4550 kg of CO₂ equivalents, 40.1 kg of SO₂ equivalents, 7.0 kg of phosphate (PO₄) equivalents and 16.1 GJ, respectively. The contribution of each process to the total environmental impact in each environmental impact category showed a similar tendency to the contribution of each process in each environmental category reported in the case of the beef fattening system as a whole. The results from this analysis showed that shortening calving intervals by 1 month reduced environmental impacts by 5.7–5.8% in all the environmental impact categories examined in the current study, and increasing the number of calves per cow also reduced environmental impacts in all the categories, although the effects were smaller.     

An Adjustable Nutrient Margin of Safety Comparison Using Linear and Stochastic Programming in an Excel Spreadsheet

A stochastic-linear program Excel workbook was developed that consisted of 2 worksheets illustrating linear and stochastic program approaches. Both approaches used the Excel Solver add-in. A published linear program problem served as an example for the ingredients, nutrients, and costs and as a benchmark in the development of the linear and stochastic programs. Standard deviations for ME and nutrients were taken or calculated from CV, and from a commercial publication of sources for amino acids. The Excel spreadsheet was set up so that the calculated margin of safety (MOS) value, according to the requested probability, was the same for both the linear and stochastic programs. As an example, the probability for meeting the nutrient value for protein was compared at 50% (MOS = 0) and 69% (MOS = 0.5) by using both linear and stochastic programming. Spreadsheet results illustrated the flexibility, accuracy, and precision of the stochastic program over the linear program in meeting the requested nutrient probability.     

暗期间断在植物生长发育中的应用研究(英文)

暗期间断属于光周期调控技术,被广泛应用于植物的生长发育研究。通过对暗期间断的类型、应用和机理三个方面研究成果进行了综述,其中在暗期间断类型部分总结了光质、间断暗期的次数和间隔时间方面的研究;在暗期间断应用部分总结了在植物形态发生、生理和生物化学方面的相关研究。在此基础上,提出了暗期间断在分子生物学研究及森林资源保护中的应用前景。