全新世早期黄河上游积石峡大型滑坡堵江事件研究

普遍认为黄河上游积石峡地区厚约30m的纹泥沉积是由于大型滑坡堵江形成的,然而,滑坡堵江时代以及堵江形成的堰塞湖纹泥沉积历时仍有争议。为了探讨研究区大型滑坡堵江时代及纹泥沉积历程,文中在纹泥底部和顶部各采集1个样品进行14C年代测定。纹泥底部样品的14C年代为9016±425 cal a B.P.,纹泥顶部样品的14C年代为7984±334 cal a B.P.。研究结果表明:黄河上游积石峡地区曾在全新世早期距今约9ka左右发生过大型堵江事件,纹泥沉积的沉积历程约为1ka,这与前人利用纹泥层厚度估算的沉积历程相吻合。该研究可为下游地区第四纪时期文明演化的研究提供一些新的参考。     

近50年陕西省无霜期的变化及果区霜冻风险分布

利用陕西省96个气象台站1961～2010年的日最低气温资料,计算了陕西各站历年霜冻的初日、终日及无霜期,并对其分布特征及年际变化进行分析。结果显示,陕西省初霜日、终霜日、无霜期等值线在陕北大致呈经向分布,在关中和陕南大致呈纬向分布;50年间,全省96站初霜日最早和最晚平均值相差44天,终霜日最早和最晚平均值相差49天,无霜期最长和最短天数平均值相差68天;全省平均初霜日呈推迟趋势,推迟幅度约为1.4天/10年;平均终霜日呈提前趋势,提前幅度约为1.7天/10年;平均无霜期呈加长趋势,加长幅度约为3.1天/10年。最后依据风险分析理论对陕西多个苹果基地县进行了花期霜冻风险分析,得出其风险的空间分布特点,结论对精确指导和开展防灾减灾工作有参考作用。     

塔里木河干流河道生态需水量研究

基于有序聚类法,在对1957-2006年塔里木河干流径流序列受人类活动显著影响突变点判别的基础上,对干流新渠满、乌斯满和恰拉3个水文断面河道逐月最小生态需水量和适宜需水量进行计算。结果表明：① 近50 a来,人类活动对干流水资源影响程度不断增大,1976年前的径流量可以近似看作自然状态;② 新渠满、乌斯满和恰拉河道年最小需水量分别为17.68×10⁸ m³、10.02×10⁸ m³和3.29×10⁸ m³,年适宜需水量分别为35.65×10⁸ m³、18.23×10⁸ m³和7.00×10⁸ m³;③一般用水期（10月至翌年3月）保证新渠满、乌斯满和恰拉河道最小需水量5.33×10⁸ m³、3.77×10⁸ m³和1.32×10⁸ m³,用水敏感期（4-9月）保证适宜需水量28.99×10⁸ m³、13.70×10⁸ m³和5.09×10⁸ m³即可确保干流河道生态系统健康。     

腐植酸在农药中的应用及发展前景

本文对腐植酸的来源、类别和在农药中的作用、应用现状等方面进行了介绍;重点阐述和分析了腐植酸类除草剂、杀虫剂、杀菌剂、植物生长调节剂的研究现状;腐植酸资源丰富,大有发展前途,并对其发展前景作了进一步展望。     

龟纹瓢虫捕食玉米蚜功能反应研究

室内研究了不同龄期的龟纹瓢虫Propylea japonica幼虫和成虫对玉米蚜Rhopalosiphum maidis的捕食功能反应。结果表明,龟纹瓢虫各龄幼虫及成虫对玉米蚜的日捕食量差异较大。龟纹瓢虫4龄幼虫对玉米蚜具有较强的捕食能力,最大日捕食量为196.85头。各龄幼虫和成虫的捕食功能反应均属于HollingⅡ型圆盘方程,经χ2检验,其理论值与观察值差异不显著。     

Advances on the Biosynthesis Mechanism of Bacterial Polysaccharides

Polysaccharide is the major component of bacterial cell that plays a significant role in the interaction between bacteria and their hosts. It aids the identification of bacteria, imparting virulence to the bacteria and adjusting host's immune response as well. Advance genomics research has deciphered several different bacterial polysaccharides sharing a common biosynthesis mechanism. The study of polysaccharides is mainly based on sequence analysis and prediction of genome in combination with metabolite analyses that still requires a detailed study. Researchers are now further focusing on their biosynthetic pathways to unveil the mechanisms underlying the diversity of these bacterial polysaccharides along with the host-pathogen interaction. It will open new doors for vaccine development and other therapeutic methods against pathogenic bacteria, and also provide technical support to control disease and cure at molecular level. This review states the mechanisms and relevant problems of biosynthesis and in vitro biosynthesis of peptidoglycan,O-antigen and capsular polysaccharides,and summarizes the application of bacteria polysaccharides in the aspects of searching for candidate antigens and controlling the targets of pathogenic bacteria and exploring genetic evolution of bacteria and biological synthesis.     

Effects of Different Milk Samples on Sensitization in BALB/c Mice

In order to study the allergenicity of camel milk,cow milk and human milk,sixty BALB/c mice were randomly divided into β-lactoglobulin (β-lg) group (positive control group),cow milk group,camel milk group,human milk group and blank group (negative control group). Each group of mice received 1 mg/g BW samples and 0.3 μg/g cholera toxin (CT) per week,while mice in control group were received PBS and CT. After six weeks of intragastric administration,some allergic symptoms,the serum specific immunoglobulin E (IgE) and immunoglobulin G1 (IgG1) levels,plasma histamine levels and vascular permeability were detected. The results showed that the body weight of mice in camel milk,human milk and blank groups were normally increased,while that in β-lg and cow milk groups tended to slow down. The serum-specific IgE,IgG1 levels and histamine level in β-lg and cow milk groups were extremely significantly higher than blank group (P<0.01),the vascular permeability was increased,and the allergy symptoms were obvious. While the specific IgE and IgG1 levels of camel milk group were extremely significantly lower than cow milk group (P<0.01),but there were no significant difference with human milk group (P>0.05),and the allergy symptoms were mild. This study showed that the sensitization of camel milk was lower than cow milk,and similar to human milk.     

健康麇鹿生长激素测定与分析

为了研究不同年龄、不同性别间麋鹿生长激素的变化水平,应用酶联免疫法测定了79只健康麋鹿血清生长激素水平.结果表明,年龄和性别不同的群体,血清生长激素分泌水平有所不同.麋鹿1岁时生长激素分泌最高,数值最大的个体也出现在1岁,值为1.52 μg/L,说明从整体上来看麋鹿1岁时生长最为旺盛.雄性生长激素分泌均值高于雌性,雄性生长激素平均值为0.6321 μg/L±0.06151 μg/L,雌性为0.6158μg/L±0.05743 μg/L,生长激素含量在1岁与2岁间存在极显著性差异(P＜0.01).说明年龄和性别是影响血清生长激素分泌的因素.     

挤压膨化加工对菜籽粕中抗营养因子含量及膨化菜籽粕对生长育肥猪生长性能的影响

本试验旨在研究挤压膨化加工对菜籽粕(RM)中抗营养因子、营养物质含量以及膨化菜籽粕(ERM)对生长育肥猪生长性能、营养物质表观消化率的影响。试验1:采用本实验室的TSE65双螺杆干法挤压膨化机和优化后的加工参数组合对饲料级RM进行挤压膨化加工,测定RM和ERM中的抗营养因子和营养物质含量。试验2:以RM和ERM为主要试验材料,选取72头体重为(33.82±3.72)kg的杜×长×大三元杂交猪,随机分成6组,每个组3个重复,每个重复4头猪。试验16周,1、3、5组分别饲喂添加6%、10%和14%RM的饲粮,试验2、4、6组分别饲喂添加6%、10%和14%ERM的饲粮;试验712周,1、3、5组分别饲喂添加10%、14%和18%RM的饲粮,试验2、4、6组分别饲喂添加10%、14%和18%ERM的饲粮。试验期为12周。结果表明:1)与RM相比,ERM中干物质、粗蛋白质、粗脂肪、粗灰分、钙和总磷含量都有所增加;ERM中粗脂肪和干物质含量显著升高(P0.05),半胱氨酸、赖氨酸和精氨酸含量显著降低(P0.05),总氨基酸含量下降了1.75%(P0.05),硫苷和植酸含量显著降低(P0.05),异硫氰酸酯和唑烷硫酮含量低于检测限0.15 mg/g,单宁含量无显著变化(P0.05)。2)16周内,同等添加量下,2、4组末重(FBW)显著高于1、3组(P0.05);4组平均日采食量(ADFI)显著高于其余各组(P0.05);各组间平均日增重(ADG)和料重比(F/G)均无显著差异(P0.05);6组粗蛋白质、粗脂肪和干物质表观消化率显著高于5组(P0.05);6组除蛋氨酸、丝氨酸和谷氨酸表观消化率与5组差异不显著(P0.05)外,其余氨基酸表观消化率均显著高于5组(P0.05)。712周内,同等添加量下,2、4组FBW高于1、3组,6组FBW低于5组,但差异均不显著(P0.05);2组粗蛋白质、粗脂肪和干物质表观消化率显著高于1组(P0.05);2组缬氨酸、异亮氨酸、赖氨酸、组氨酸、苏氨酸、天冬氨酸、酪氨酸、谷氨酸、甘氨酸、半胱氨酸、脯氨酸和总氨基酸表观消化率显著高于1组(P0.05)。由此可见,挤压膨化加工能提高RM的营养价值并降低多种抗营养因子含量,在育肥猪饲粮中添加ERM可以提高育肥猪的生长性能和营养物质表观消化率。30-60 kg的育肥猪饲粮中ERM适宜添加量为10%,61120 kg的育肥猪饲粮中ERM适宜添加量为14%。     

东方蝾螈外部体型指数回归方程的建立

为了探讨东方蝾螈在人工养殖效果评估方面 ,在确定屠宰或捕捞的大小与时间的适宜度方面 ,在生理、病理分析时 ,在治疗时间和用药量等诸方面 ,都达到取材时期的合理性问题 ,测定了东方蝾螈的身型指数 ,并初步建立了回归方程Y =- 2 5 0 +0 .6 2X1 ,并对相关数据的处理方法进行了探讨。