网络环境下专业图书馆工作的转变   总被引：1，自引：0，他引：1  

闫险峰 《农业图书情报学刊》2004,16(11):155-156

本文论述了网络环境下专业图书馆转变业务工作的措施及需要注意的问题。  相似文献   

阴离子饲粮对活体外瘤胃发酵特性和营养物质消化的影响     

张跃文  孟庆翔  刘庆平  许曾曾 《中国畜牧杂志》2006,42(21):34-37

应用双外流连续培养系统模拟瘤胃发酵,研究不同阴阳离子差(DCAD)水平的阴离子饲粮对活体外瘤胃发酵和营养物质消化率的影响。试验分2期进行,每期12个发酵罐,3个1组,分别投入4种不同DCAD水平的饲粮:+120-、9-、77-、145 mEq/kgDM,后3种饲粮通过添加阴离子添加剂降低DCAD。结果表明:①阴离子饲粮对瘤胃发酵pH值、氨态氮浓度、总挥发性脂肪酸浓度、主要挥发酸的摩尔比例均没有显著影响(P>0.2)。②对饲粮干物质、有机质、中性洗涤纤维、粗蛋白消化率没有显著影响(P>0.2)。③对瘤胃微生物合成效率没有显著影响(P>0.2)。试验结论为阴离子饲粮对活体外瘤胃发酵和饲粮营养物质消化率没有显著影响。  相似文献   

草地补播对甘南草原高寒草甸高原鼢鼠食性的影响     

张彩军  姚宝辉  王小燕  孙小妹  苏军虎 《草业科学》2022,38(5):967-975

本研究阐明草地补播对高原鼢鼠(Eospalax baileyi)食性的影响,能为其防控和草地管理提供重要参考.利用胃容物显微分析法,研究高原鼢鼠在甘南高寒草甸补播草地和退化草地的食性与生态位差异.结果发现,草地补播显著改变了高原鼢鼠的食物资源,退化草地下优势植物主要是菊科(Asteraceae,45.30％)、唇形科(Lamiaceae,26.40％)和蔷薇科(Rosaceae,18.72％),而补播后则变为禾本科(Poaceae,37.00％)、蔷薇科(25.68％)和莎草科(Cyperaceae,16.54％).退化草地中高原鼢鼠采食15科27属27种植物,食物比例中蔷薇科(45.72％)、禾本科(19.68％)和廖科(Polygonaceae,17.11％)最高.而在补播草地高原鼢鼠采食15科25属28种植物,主要采食蔷薇科(40.71％)、禾本科(25.32％)、廖科(11.70％)和莎草科(11.45％).草地补播影响了高原鼢鼠采食植物的比例,且食性的生态位宽度、食物的多样性指数和均匀度有所提高.综上所述,补播可以通过减少杂类草的比例来减少高原鼢鼠的食物来源,喜食植物的减少可能会增加高原鼢鼠的觅食时间从而增加高原鼢鼠的觅食代价.通过补播影响高原鼢鼠食性是其生态防控的一个有效途径.  相似文献   

蚁形郭公虫人工饲料及繁殖饲养研究     

吕军  叶辉  刘宏屏  母其爱 《中国森林病虫》2006,25(5):28-31

在Reeve提出的配方基础上,研制出了适宜蚁形郭公虫Thanasimus formicarius的人工饲料配方,并以该配方饲料为基础,形成相应配套的蚁形郭公虫饲养技术。  相似文献   

婴儿营养米粉配方的优化设计     

李忠海  李安平 《中南林业科技大学学报(自然科学版)》2001,21(1):54-57

以世界卫生组织和联合国粮农组织推荐的营养素供给量标准以及我国建议的营养素供给量标准为基准，以婴儿为对象，采用混合惩罚函数法，借助计算机技术，对婴儿经常食用的营养米粉进行了优化设计，获得了最佳配方.计算过程表明，该方法可行，结果可靠.该方法亦可用于各类营养保健食品的最优设计.  相似文献   

C化学位移特点研究   总被引：2，自引：0，他引：2  

王宗德  肖转泉  安鑫南 《林产化学与工业》2002,22(2):86-88

由诺卜醇和丙酸酐合成了丙酸诺卜酯，用MS，IR，^1HNMR及^13CNMR分析进行了结构表征，利用^13C化学位移分析出其构象是：C-1-C-2-C-3-C-4-C-5部分处于同一平面，整个6，6-二甲基双环[3.1.1]庚-2-烯部分呈“Y”形。丙酸诺卜酯可以看成是阿朴蒎烯在C-2发生取代的衍生物，取代基对^13C化学位移的影响主要集中在C-2，C-1和C-3，对其它碳原子的影响比较小。  相似文献   

Bats as the main prey of wintering long‐eared owl (Asio otus) in Beijing: Integrating biodiversity protection and urban management          下载免费PDF全文

Long TIAN  Xuwei ZHOU  Yang SHI  Yumin GUO  Weidong BAO 《Integrative zoology》2015,10(2):216-226

The loss of biodiversity from urbanized areas is a major environmental problem challenging policy‐makers throughout the world. Solutions to this problem are urgently required in China. We carried out a case study of wintering long‐eared owls (Asio otus) and their main prey to illustrate the negative effects of urbanization combined with ineffective conservation of biodiversity in Beijing. Field monitoring of owl numbers at two roosting sites from 2004 to 2012 showed that the owl population had fallen rapidly in metropolitan Beijing. Analysis of pellet contents identified only seven individuals of two species of shrew. The majority of mammalian prey comprised four bat and seven rodent species, making up 29.3% and 29.5% of the prey items, respectively. Prey composition varied significantly among years at the two sample sites. At the urban site the consumption of bats and rodents declined gradually over time, while predation on birds increased. In contrast, at the suburban site the prey composition showed an overall decrease in the number of bats, a sharp increase and a subsequent decrease in bird prey, and the number of rodent prey fell to a low point. Rapid development of real estate and inadequate greenfield management in city parks resulted in negative effects on the bird and small mammal habitat of urban areas in Beijing. We suggest that measures to conserve biodiversity should be integrated into future urban planning to maintain China's rich biodiversity while also achieving sustainable economic development.  相似文献   

基于充油流量与曝气程度的拖拉机动力换向性能研究     

闫祥海  魏海江  刘孟楠  赵俊峰  张静云  徐立友 《农业机械学报》2023,54(8):381-393

围绕拖拉机动力换向离合器充油流量易受温度、回位弹簧刚度和预紧力等因素影响,液压油在加注及工作过程中易受空气污染,导致液压油空气含量增加的工程应用问题,探究了不同充油流量及曝气程度对动力换向性能的影响。以换向时间、冲击度、滑摩功和磨损量为评价指标对换向性能进行了评估,以期提高拖拉机动力换向品质、工作效率和传动系使用寿命。以东方红LF2204型拖拉机TX4A传动系为研究对象,建立了考虑充油流量和曝气程度的动力换向过程数学模型,基于ADAMS、Matlab/Simulink和AMESim平台分别建立了换向离合器机械模型、控制模型和液压模型,对拖拉机Ⅰ挡作业时前进挡切换为倒退挡的工况进行了仿真分析与台架试验验证。仿真结果表明：当液压油曝气程度为0.1%,充油流量分别为16、14 L/min时,与20 L/min流量相比,换向时间分别增长20%和43%,变速器最小输出转矩分别下降26%和52%,滑摩功分别上升33%和78%,最大冲击度分别下降11%和18%,最大磨损量分别上升24%和44%。当充油流量为20 L/min,曝气程度分别为1%和5%时,与0.1%曝气程度相比,换向时间分别增长26%和...  相似文献   

Food and water intake and selective feeding in rabbits on four feeding regimes     

A. L. Meredith 《Journal of animal physiology and animal nutrition》2014,98(5):991-1000

Diet plays an important role in maintaining rabbit health. Feeding an incorrect diet, particularly a low fibre diet, has been linked with digestive, dental and urinary tract disease. However, food intake and dietary requirements have been poorly studied in pet rabbits. This study assessed the effects of two commonly fed pet rabbit diets [extruded nuggets with hay (EH) and muesli with hay (MH)] alongside hay only (HO) and muesli only (MO) on food and water intake in 32 Dutch rabbits. Dry matter (DM) intake was greater in the HO group and lower in the MO group than in the EH and MH groups (p < 0.001). The portion of the diet made of hay was greater in the EH group than in the MH group (p < 0.001). Water intake was positively correlated with DM intake and was greatest in the HO group (p < 0.001). Selective feeding occurred in all rabbit groups fed muesli, whether or not hay was also available. Pellets were rejected, and grains and extrudates selected. The presence of selective feeding in all rabbits fed muesli leads to the consumption of an unbalanced diet. In addition, hay intake and water intake were lower when muesli was fed. Conclusions drawn from this study are based on general recommendations for pet rabbits, and clinical disease may have developed by feeding the study diets over a longer time period, as many diet‐related conditions typically present in older rabbits. However, the study demonstrates that the feeding of muesli diets cannot be recommended.  相似文献   

一种桔小实蝇幼虫人工饲料的配制     

杨珊  陈鹏  袁瑞琳 《林业调查规划》2014,(1):76-78

以豆渣、麦胚、酵母粉、蔗糖为主要原料,配制成桔小实蝇幼虫人工饲料,与天然饲料(水果)和现常用的人工配方饲料进行饲养试验,测定采用3种饲料饲养的桔小实蝇的卵孵化率、化蛹率及羽化率。结果表明,以豆渣为主要原料的人工饲料配制成本低廉,饲养效果接近天然饲料。  相似文献