杨歧山毛竹枯梢病发生规律及综合防治技术

毛竹枯梢病的发生与气候和竹林的经营管理水平密切相关。通过实施清除病原，隔断侵染源、钩梢、垦复、施肥、烟剂防治等综合防治技术，使病害发生面积下降了90％，消灭了重度和中度危害区。发病率和感病指数分别下降了94％和85％。     

Pasteurella multocida septicaemia in fallow deer (Dama dama)

Thirteen of 100 fallow deer, aged between 6 months and 10 years, died over a 5 week period. The deaths occurred in 2 outbreaks 3 weeks apart. Both outbreaks were preceded by at least 3 days of cold wet and windy weather, and were associated with water-logged pastures. Affected animals were usually found dead, with a frothy blood-stained nasal discharge. In the 8 deer necropsied, gross lesions included widespread subserosal petechial haemorrhages, severe pulmonary congestion and oedema with froth-filled airways, and fibrinous pneumonia and pleurisy in 4 deer. Two deer, also, had extensive subcutaneous petechial and ecchymotic haemorrhages and oedema of skeletal musculature. Histologically, the most significant lesions were present in the lungs. Moderate to severe pulmonary congestion and oedema, with fibrinous exudation into alveoli and septal oedema, were present in all deer. In some deer these changes were accompanied by a diffuse infiltration with polymorphonuclear leucocytes. Pasteurella multocida was isolated from a range of tissues from 7 of 8 deer examined. The remaining animal had been treated with antibiotics 8 hours before death. The isolates had identical polyacrylamide gel electrophoresis patterns and were of the same antigenic type-Carter group A, Heddleston type 3,4.     

韭菜花芽分化过程及解剖学特征研究

为明确韭菜花芽的分化过程及内部结构特征,掌握不同类型韭菜的生殖生长周期,选用深休眠韭菜品种‘平韭2号’、浅休眠韭菜品种‘四季青’和‘薹韭’的三年生植株为试验材料,采用石蜡切片技术,观察韭菜茎尖生长点的变化。结果表明：可将韭菜花芽的分化过程分为4个时期——花芽未分化期、总苞和花序原基分化期、小花原基分化期与花部原基分化期。在统一的栽培条件下,韭菜品种不同,启动花芽分化的日期也不同。浅休眠品种‘四季青’比深休眠品种‘平韭2号’早约28 d,而同为浅休眠类型的‘薹韭’则比‘平韭2号’早约62 d。另外,花芽分化过程中各时期的持续时间在不同品种之间也表现出一定差异。     

改进PSO算法在电力系统无功优化中的应用

介绍一种改进粒子群的无功优化方法。采用简化粒子群优化方程和添加极值扰动算子两种策略加以改进,提出简化粒子群优化（SPSO）算法、带极值扰动粒子群优化（DPSO）算法,并将二者结合起来提出带极值扰动的简化粒子群优化（DSPSO）算法。以IEEE6节点系统为例进行无功优化计算,并与其他算法进行比较,结果表明：该算法具有较快的收敛速度及较强的全局搜索能力,可较好地解决电力系统的无功优化问题。     

我国西北平原地区林业生态服务功能评价

[目的]评价我国西北平原地区林业的生态服务功能。[方法]通过对西北平原地区林业的调查与监测,以县为最小单位,采取普查与典型调查相结合的调查方法,在评价上利用物质量评价法对西北地区平原林业的生态服务功能进行了评估。[结果]2005年西北地区平原林业在涵养水源、保持土壤、植被固碳、土壤固碳、植被制氧、吸收二氧化硫和滞尘方面均发挥了巨大作用,其各自生态服务功能值分别为32075.8万m3/a、2.8×106、1254、2752.8、3354.3、53.0和8510万t/a。[结论]为我国西北地区平原林业的生态服务功能研究奠定了基础。     

中亚热带常绿阔叶林林隙与物种多样性的关系研究

对万木林中亚热带常绿阔叶林非林隙与林隙内物种多样性及物种多样性随林隙大小的变化规律研究结果表明 ,万木林常绿阔叶林林隙内物种多样性高于非林隙内 ,乔木树种物种多样性随林隙大小的变化呈双峰曲线 ,其物种多样性为 2 0 0～ 30 0m2 面积林隙内达最大值 ;而灌木树种多样性随林隙大小的变化呈单峰曲线 ,其物种多样性为 4 0 0～ 5 0 0m2 面积林隙内达最大值。     

Estimation of (co)variance components for reproductive traits in Angus beef cattle divergently selected for blood serum IGF-I concentration

The objective of this study was to obtain estimates of (co)variance components for reproductive traits and insulin-like growth factor-I (IGF-I) concentration. Data were from a divergent selection experiment for blood serum IGF-I concentration in Angus beef cattle. Numbers of observations for mean IGF-I concentration of three blood samples taken at d 28, 42, and 56 of the 140-d postweaning test, scrotal circumference (SC), percentage of motile sperm cells (PMSC), percentage of morphologically normal sperm cells (PNSC), age of heifers at first calving (AFC), and calving rate (CR) were 1,848, 825, 596, 765, 294, and 2,092, respectively. Total number of animals in the numerator relationship matrix, including base animals, was 2,864, of which 1,861 were inbred. Estimates of direct heritability for IGF-I concentration of three blood samples collected at d 28, 42, and 56 of the postweaning test and for mean IGF-I concentration were 0.43+/-0.08, 0.51+/-0.09, 0.41+/-0.08, and 0.50+/-0.08, respectively. Estimates of direct heritability for SC, PMSC, PNSC, AFC, and CR were 0.51+/-0.13, 0.08+/-0.12, 0.47+/-0.07, 0.26+/-0.28, and 0.11+/-0.05, respectively. With the exception of age at first calving, estimates of maternal heritability and proportion of phenotypic variance that were due to permanent environmental effects of the dams were smaller than 0.21. Observations for calving rate were entered as either 1 (if calved) or 100 (if not calved). Estimates of additive genetic correlations of mean IGF-I concentration with SC, PMSC, PNSC, AFC, and CR were 0.35+/-0.11, 0.43+/-0.32, 0.00+/-0.03, -0.14+/-0.33, and -0.41+/-0.16, respectively. Environmental and phenotypic correlations for all of the traits with IGF-I measurements were smaller than 0.23. These results suggest that selection for increased serum IGF-I concentration should result in increased scrotal circumference, percent motile sperm cells, and calving rate.     

不同水分条件下苔藓结皮光合能力对氮素添加量的响应

[目的]探究苔藓结皮失水过程中光合能力对不同梯度氮添加的响应,为进一步研究苔藓结皮对氮沉降的响应过程以及为干旱、半干旱区荒漠生态系统的管理提供理论依据。[方法]选取毛乌素沙地的优势藓种拟双色真藓(Bryum pachytheca)为研究对象,在控制条件下采用氮添加的模拟试验手段。[结果]苔藓结皮净光合速率在低于0.2g/(m2·a)的氮添加量时受到促进,在高于0.2g/(m2·a)的氮素添加量下,低水分含量时被抑制,高水分含量时会受促进;同时,0.2g/(m2·a)是苔藓结皮能承受的最优氮添加量,此时苔藓结皮的光合固碳能力达到最大,年光合固碳量为对照条件的2倍。[结论]氮沉降引起的氮素增加对于干旱、半干旱区苔藓结皮的光合能力以及固碳潜力具有显著的影响。