饲粮不同氯水平对笼养生长蛋鸭体内酸碱平衡的影响

本试验旨在研究玉米-豆粕型饲粮不同氯水平对笼养生长蛋鸭体内酸碱平衡的影响。选用300只28日龄体重相近的金定鸭,随机分为5个处理组,分别饲喂含氯0.06%、0.12%、0.18%、0.30%和0.60%的饲粮,每个处理组设10个重复,每个重复6只蛋鸭。结果显示:各处理组之间血清Cl-含量和Na+含量随饲粮氯水平的升高呈线性增加;各组间血液pH和HCO3-浓度差异不显著(P0.05),但是随氯水平增大血液逐渐趋于酸性。综合分析,低水平或高水平的氯可影响蛋鸭体内的酸碱平衡,饲粮中含0.12%～0.18%的氯可使笼养蛋鸭体内达到最佳的酸碱平衡。     

载体大小对木聚糖酶过量表达的影响

将黑曲霉Aspergillus niger木聚糖酶基因与表达载体pET21a(5 443 bp)和pET20b(3 716 bp)重组,而后转化E.coli BL21(DE3) 细胞,发现大载体细胞和小载体细胞中质粒DNA浓度为(4.6±0.01),(5.5±0.01)g·L-1,木聚糖酶含量为(57.2±10.6),(140.2±22.1) mg·L-1,木聚糖酶酶活性为(6.6±0.2),(69.6±11.2) U·mL-1.相对于大载体细胞,小载体细胞质粒浓度增加19.5%,木聚糖酶含量增加1.45倍,木聚糖酶活性增加9.5倍,说明载体大小对外源蛋白表达的影响效应呈递增趋势.由此可见,小型载体在表达外源蛋白时更利于减少宿主细胞的负担,利于质粒扩增并提高基因拷贝数,最后提高木聚糖酶含量及活性.     

RO法浓缩稀土氯铵废水预处理动态实验

指出了稀土氯铵废水成分复杂.反渗透膜对进水水质要求严格,因此进膜前必须进行预处理.其废水中舍油(17.2 mg/L)和COD值(156mg/L),通过炉灰渣和活性炭联合吸附可降到0.5和20mg/L以下;通过投加氨水、阻垢剂和适量的盐酸可使废水回收率为75%而不致结垢.经砂石过滤和活性炭过滤后,SDI值可降到1以下.通过以上工序处理,稀土氯铵废水可达到膜进水水质的要求.     

混凝土桥梁耐久性环境因素及其防护涂料分析

桥梁作为交通枢纽发挥着越来越重要的作用。然而,大量混凝土桥梁在没有达到预定的使用年限,就出现了耐久性严重退化现象。本文分析混凝土桥梁所处的腐蚀环境(大气、水、氯盐及日照)和腐蚀特点,介绍国内外桥梁防护涂料的技术要求及防护涂装配套体系的研究现状,针对目前防护涂料缺乏考虑日照对混凝土桥梁的不利影响,提出应用热反射隔热涂料的趋势,为今后混凝土桥梁用功能性防护涂料提供参考。     

锦州市自来水硬度特点及净化对策研究

通过表征锦州自来水,阐述了锦州自来水的特点,主要是高硬度特性,同时为了得到精确数值,采用EDTA络合滴定的方法进行了测定 ,得到总硬度数值为368.4,并采用煮沸法得到了锦州城市自来水的暂时硬度和永久硬度 ,分别为61.2和307.2.通过对数据分析,永久硬度所占比重大,提出了为去除永久硬度,建议采用离子交换吸附法去除.     

扎陵湖-鄂陵湖自然保护分区湿地生物群落结构调查

指出了扎陵湖-鄂陵湖自然保护分区共记录有野生动物88种,其中鸟类51种,兽类29种,爬行类1种,鱼类7种,含国家Ⅰ级保护动物4种、Ⅱ级保护动物13种;植被种类共计17种,隶属于6目8科,其中以禾本科(Gramineae)、菊科(Compositae)和蔷薇科(Rosaceae)植物为优势种。分析了间歇性积水草甸土、无积水草甸土和无积水沙土3个不同土壤环境生物群落结构的Shannon-wiener多样性指数、Pielou均匀性指数和Jaccard指数,结果表明:无积水沙土生物群落多样性和均匀度均最高,间歇性积水草甸生物群落结构与无积水草甸生物群落结构相似度最高,而间歇性积水草甸生物群落结构与无积水沙土生物群落结构相似性最低;植物群落呈现出禾本科植物比例依次减少,双子叶杂草类依次增加的趋势;动物群落呈现湿地鸟类数量依次减少,非湿地鸟类和兽类依次增加的趋势。     

沂河山东段水体中重金属的分布与污染评价

[目的]研究沂河山东段水体中重金属Cu、Cr、Pb、Cd、Hg、As的分布和污染状况。[方法]采用ICP-OES法测定了沂河山东段水体中重金属Cu、Cr、Pb、Cd、Hg、As的含量,并利用单因子污染指数法对其进行污染评价。[结果]沂河水体中Cu和Cr含量极低,未检测出;Pb、Cd、Hg、As 4种重金属元素的平均含量分别为0.023 40、0.000 94、0.006 13和0.043 70 mg/L,分别符合国家Ⅲ类、Ⅰ类、劣Ⅴ类和Ⅰ类地表水质标准;由单因子污染指数法评价得出,河水中Pb和Cd单因子污染指数均小于1,为清洁水平;As单因子指数最大值是1.87,最小值是0.22,综合污染指数为1.50,为轻微污染;Hg单因子指数值均在10以上,最大值为135.6,综合污染指数为105.2,沂河山东段水体受到非常严重的Hg污染。[结论]该研究为沂河沿岸人们的健康及畜牧业的发展提供科学依据和防控基础。     

落叶松人工林大径材培育森林抚育技术

按照落叶松大径材培育模式,针对孟家岗林场68林班13小班的落叶松人工林生长状况,根据林分直径分布模型算出间伐时林分的直径分布,按照下层抚育间伐的方法确定间伐强度,科学调整林分结构,促进林分健康生长。     

The effect of oviposition experience of adult Microplitis pallidipes parasitoids on discrimination between nucleopolyhedrovirus-infected and healthy Spodoptera litura larvae

Using multiple pest-mortality sources is a basic tenet of IPM, but they may not always be compatible. To that end, we examined compatibility of parasitism and nucleopolyhedrovirus (NPV) infected. Specifically, we examined the effects of prior oviposition experience by Microplitis pallidipes on its ability to distinguish NPV-infected from healthy larvae of Spodoptera litura. We found that time spent searching for hosts was significantly lower, while the number of attacks, percentage of first attacks, and parasitism rate were all significantly higher in healthy versus virus-infected hosts for parasitoids that had experienced healthy hosts. Meanwhile, parasitoids that had experienced infected hosts spent significantly more time searching for infected hosts starting on day 2. For these parasitoids, the number of attacks, percentage of first attacks, and parasitism rate were all significantly lower from day 2 in virus-infected versus healthy larvae. We found no significant differences between parasitoids without experience versus ones experienced with infected hosts in search time for infected hosts, number of infected host attacks, or percentage of first attacks on infected hosts. In comparison, parasitoids that had experienced healthy hosts spent less time searching for healthy hosts than parasitoids without experience, and displayed a higher frequency of attack on healthy hosts and a higher percentage of first attacks on healthy hosts. Experience with healthy larvae aided parasitoids in distinguishing healthy from virus-infected larvae, but experience with virus-infected larvae did not convey the same discrimination. This information provides a better understanding of how to integrate NPV applications with naturally occurring parasitism for this pest in crops.