Biomechanics in young and adult italian standardbred trotter horses in real racing conditions

This study was undertaken to characterize and establish the kinematic standards of Italian standardbred trotter horses in real racing conditions. Certain parameters, such as the angles of both front and hind fetlock joints, stride length, stride frequency and average speed in youngs and adults are presented, examinated and compared with statistical tests. The angles and stride length were obtained using ONTRACK software over frames extracted from two CANON MV630i digital videocameras. For the stride frequency, a third identical videocamera filmed the horses to count the number of beats per minute. The average speed was calculated by multiplying the stride frequency by the stride length and transforming the result into kilometers per hour. The data reveal that as speed increases, younger horses have more extended fetlock joints than adults. Contrary to this, at the maximum speed (hereafter referred to as sprint speed) the adults increase both their stride frequency and stride length, while young horses increase stride frequency and decrease stride length. We think that the knowledge of these parameters in competition breeds could have potential relevance as they may reveal early indicators of the development of proper and adequate characteristics in young horses of those breeds.     

广义奇异积分算子的加权φ有界性

在齐型空间上定义了一类广义奇异积分算子证明了该算子的加权φ有界性，这里φ是Ｙｏｕｎｇ函数，同时给了它的一些应用。     

"三渔问题"与渔业管理制度——基于辽东湾海蜇捕捞的考察

相比"三农问题","三渔问题"远未获得重视.文章通过对辽东湾海蜇捕捞的考察,沿着渔业资源的特征这条主线,深入地探讨渔民的经济行为和社会冲突,揭示现存海蜇管理制度的缺陷.笔者认为,对于辽东湾海蜇捕捞,基于产权的渔业共同管理模式是一种有效的方案.     

一种有效提取无核荔枝幼胚总RNA的方法

笔者采用改良CTAB法从富含多酚的无核荔枝幼胚中提取总RNA,并用甲醛变性琼脂糖凝胶电泳和紫外分光光度计对所提RNA质量进行检测,旨在为多糖、多酚含量较高的植物材料RNA的提取提供一种有效方法。     

新麦草幼穗愈伤组织诱导影响因素研究

[目的]探讨愈伤组织诱导取材时间、培养基筛选、激素调节及幼穗成熟度对新麦草幼穗愈伤组织诱导的影响。[方法]以新麦草2个品种幼穗为外植体接种于附加不同激素的MS和N6培养基上进行愈伤组织诱导培养。[结果]2种培养基诱导的愈伤组织质地无明显差异。山丹新麦草幼穗最佳诱导培养基为N6添加2,4-D2mg/L,P8401为MS添加2,4-D6mg/L。ABA添加于MS培养基可显著促进愈伤组织生长。山丹新麦草幼穗愈伤组织培养添加ABA适宜浓度为1.5mg/L,P8401为0.3mg/L。CH仅具有加速愈伤生长的效果,但对新麦草愈伤组织诱导促进作用不大。P8401新麦草1～2cm新生幼穗材料作为愈伤诱导外植体最为理想,山丹新麦草5～6cm较成熟幼穗在MS上愈伤诱导率高于幼嫩小穗。[结论]2种培养基均可用于新麦草幼穗愈伤组织诱导。外植体的取材时间在组织培养中是关键因素。     

一种有效提取无核荔枝幼胚总RNA的方法（英文）

A total RNA extraction method for young embryo of seedless litchi was introduced.CTAB,Phenol(saturated with water),chloroform,Guanidine isothiocyanate were used as main extraction reagents.Polyphenolic compounds were removed effectively by added PVP into the extraction buffer solution.RNA was purified intensively by phenol,chloroform extraction,and ethanol deposition after deposited by LiCl.Both the results of formaldehyde denatured agarose gel electrophoresis and ultraviolet spectrophotometer analysis showed high integrity and purity of RNA.So the quality of extracted RNA could meet the demand of most molecular biology experiments that require higher quality RNA.     

硝酸钙和氯化钠不同浓度对番茄苗期光合生理特性的影响

以Ca (NO3 ) 2 和NaCl按 5∶1的比例均匀混合设计 0 % ,0 1 % ,0 2 % ,0 3% ,0 5 % ,0 7%的盐浓度 6个处理 ,模拟宁夏不同日光温室的土壤含盐量 ,以番茄为试验对象 ,研究了不同浓度盐份对番茄苗期叶绿素含量 ,光合作用 ,荧光参数的影响。结果表明 ,在 0～ 0 5 %盐份处理对叶绿素含量有促进作用 ,在 0 1 %盐份处理对光合作用和光能转换率有刺激作用 ,但随着盐份浓度的加大 ,叶绿素含量降低 ,光合作用下降 ,光能转换率降低 ,植株生长发育受到了明显的抑制     

冷箭竹更新幼龄芽种群的数量统计

臣龙自然保护区大熊猫栖息地冷箭竹更新幼龄芽种群密度平均为３９．８株／ｍ＾２,各龄级基株的芽种群密度排序是１１年生〉１２年生〉１２年生〉１０年生〉９年生〉８年生,无性系群仅１年～７生植株具有发芽能力,且主要集中于２年～５年生的无性上株,呈现出３年生〉２年生〉４年生〉６年生〉１年生〉６年生〉７年生的动态格局,不同林分类型和海拔高度的冷箭竹芽种群密度各异,就林分类型而高,岷江冷杉～冷箭竹林数量最高,铁松     

关于加快新疆青年农业科技人才队伍建设的对策研究

文章以新疆农科院为例,分析了青年农业科技人员的队伍结构,并从工作条件、培养机制、激励机制、考评机制、生活条件等方面指出了青年农业科技人才队伍建设存在的问题,提出了为青年农业科技人员提供专项经费支持、建立多形式的青年农业科技人员培养机制、实施科技创新团队建设工程等对策建议,以期为青年农业科技人才队伍建设提供借鉴。     

幼林化学控草抚育技术研究

试验探讨了在幼林抚育中使用森草净的适宜技术,开展了森草净不同剂量、喷施时间以及单独使用或与其他除草剂配比使用的控草效果。结果表明：不炼山造林的幼林在春季杂草萌芽前罩住幼树,进行带面喷施有效成份20～60ml/667m2的森草净,可有效地控制幼林地杂草。杂草萌芽后用一定剂量的森草净与草甘膦、森泰混合使用,结合劈草抚育,效果更佳。这种＂不炼山耙带造林、幼林化学控草抚育＂的新模式,既实现了幼林少耕,又极大地提高了林业的经济效益和生态效益。