高校图书馆文献采访工作中的信息不对称及其对策

信息不对称理论是微观信息经济学研究的一个核心内容,在图书馆文献采访活动中,也普遍存在着信息不对称现象。在此探讨了两种信息不对称的表现形式:一种来源于图书馆和书商之间;另一种是图书馆和读者之间;运用信息不对称理论,分析了其成因并提出了抑制措施,以便高校图书馆更好地为读者服务,促进高校图书馆健康有序发展。     

免疫佐剂研究进展及前景展望

本文从免疫佐剂的发现、作用机理、发展进行论述,综述了传统免疫佐剂、细胞因子佐剂、天然来源佐剂及新型免疫佐剂的类别与免疫机理,并就免疫佐剂的发展前景进行了展望。     

Genome-wide Association Study on Abdominal Fat Weight in Jinghai Yellow Chicken

The study was conducted to reveal the genetic basis of abdominal fat weight trait and scan molecular markers which could be used to improve the abdominal fat weight.The abdominal fat weight of female Jinghai Yellow chicken in core group were measured after being slaughtered.Genome-wide association study was carried out using specific-locus amplified fragment sequencing technology to detect SNPs associated with abdominal fat weight.Finally, five SNPs that associated with abdominal fat weight and reached suggestive genome-wide significance (P<1.1×10^-5) were found, and four of them (rs18144674, rs18144680, rs12246236 and rs12257795) reached chromosome significance level.Three SNPs (rs18144674, rs18144680 and rs19745739) located in a 1.6 Mb area of chromosome 2, and two SNPs (rs12246236 and rs12257795) located in a 12 kb area of chromosome 14.Genes in the candidate regions with 0.1 Mb windows were screened.Finally, eleven candidate genes of VIM, TRDMT1, AXIN1, PDIA2, ARHGDIG, gga-mir-1763, gga-mir-1564, CLCN7, ECL1, DNASE1 and SDOS were obtained.The molecular function and biological processes were analyzed using GO database.The results showed that those genes might be candidate genes affecting abdominal fat weight in Jinghai Yellow chicken.     

How do environmental factors and different fertilizer strategies affect soil CO2 emission and carbon sequestration in the upland soils of southern China?

Upland soils have been identified as a major CO₂ source induced by human activities, such as fertilizer applications. The aim of this study is to identify the characteristics of soil CO₂ emission and carbon balance in cropland ecosystems after continuous fertilizer applications over decades. The measurements of soil surface CO₂ fluxes throughout the years of 2009 and 2010 were carried out based on a fertilization experiment (from 1990) in a double cropping system rotated with winter wheat (Triticum aestivum L.) and maize (Zea mays L.) in upland soil in southern China. Four treatments were chosen from the experiment for this study: no-fertilizer application (SR), nitrogen–phosphorus–potassium chemical fertilizers (NPK), NPK plus pig manure (NPKM) and pig manure alone (M). Results showed that the mean value of soil CO₂ fluxes from 08:00 to 10:00 am could represent its daily mean value in summer period (June–August) and that from 09:00 am to 12:00 pm for the rest season of a year. Soil temperature and moisture combined together could explain 70–83% of variations of CO₂ emission. Annual cumulative soil CO₂ fluxes in the treatments with manure applications (8.2 ± 0.8 and 11.0 ± 1.2 t C ha⁻¹ in 2009, and 7.9 ± 0.9 and 11.1 ± 1.2 t C ha⁻¹ in 2010 in NPKM and M, respectively) were significantly higher than those in the treatments with non-manure addition (2.5 ± 0.2 and 3.4 ± 0.2 t C ha⁻¹ in 2009, and 2.1 ± 0.2 and 3.7 ± 0.3 t C ha⁻¹ in 2010 in SR and NPK, respectively). However, the treatments with manure applications represented a carbon sink in the soil (carbon output/input ratio < 1.0), which demonstrated potential for carbon sequestration.     

STAT5b基因的遗传多态性及其与京海黄鸡体重和繁殖性状的关联分析

以京海黄鸡、AA鸡、尤溪麻鸡、边鸡等4个鸡品种为研究对象,采用PCR-SSCP方法检测信号转导和转录激活子5b(STAT5b)第7外显子和部分内含子7的多态性,并分析其对京海黄鸡体重和繁殖性状的遗传效应。结果显示,在STAT5b第7内含子区域检测到1处突变(8 066bp C→T)。在4个鸡品种中均检测到AA、AB、BB 3种基因型,χ2检验结果表明,除京海黄鸡外其余3个品种群体在该座位均达到Hardy-Weinberg平衡(P>0.05)。最小二乘分析表明,京海黄鸡3种基因型个体的出生重和开产日龄存在显著差异(P<0.05)。     

杂交鲷与黑鲷投喂频率的比较研究

比较了黑鲷(Acanthopagrus schlegelii)♀×真鲷(Pagrus major)♂杂交子二代(杂交鲷或杂交F2)与黑鲷幼鱼在不同投喂频率下生长性能、生理生化指标的差异表现,为新品种选育提供基础依据.选用杂交F2及黑鲷幼鱼为研究对象,设4个投喂频率组(1T:1次·d?1、2T:2次·d?1、3T:3次·...     

缩放型喷嘴空化流动特性的数值分析

为研究空化射流结构及剪切空泡的形成演化,文中采用RANS-LES混合模型方法对一种缩放型喷嘴的空化水射流进行数值模拟计算,对比分析了不同扩张角喷嘴对射流流场的影响以及空泡初生阶段其形态、速度、湍动能等物理量的变化规律.计算结果发现:喷嘴扩张角对空化射流影响较大,当扩张角为60°时其空化性能更优;由于空化射流速度非常高,射流剪切层内存在较大的速度梯度,两侧流体发生频繁的能量交换并产生许多旋涡结构;空化现象最早发生在喷嘴喉管处并逐渐向扩张段及喷嘴出口附近运动发展,空化程度不断增大,不同时刻径向截面内的各参数均沿轴心对称分布,空泡形态呈圆环状,并随着时间推移圆环面积逐渐增大.研究结果对于提高空化水射流性能、拓宽空化水射流应用范围、揭示空化水射流特性等方面具有一定的应用价值及指导作用.     

鸡腿菇转化桑叶发酵液的降血糖作用研究

研究了鸡腿菇转化桑叶发酵液的降血糖作用,测定了糖尿病小鼠喂养鸡腿菇转化桑叶发酵液后血糖、血脂及肝脏、肾脏组织中的超氧化物岐化酶酶活等指标,并分析了发酵液中的成分。结果表明,鸡腿菇转化桑叶发酵液可以降低血清中血糖、果糖胺、甘油三酯、丙二醛含量,提高脏器中超氧化物岐化酶活性;同时,与未转化桑叶的发酵液相比,鸡腿菇转化桑叶发酵液中具有降血糖作用的黄酮和多酚含量显著增加高,进一步分离得到的4,5-二羟基,2-甲氧基-苯甲醛含量也显著提高。无论从功效还是发酵液成分变化都已说明鸡腿菇转化桑叶发酵液具有很好的降血糖作用,为药用真菌转化中药提高降血糖作用提供了参考。     

基于TM影像的玛多县湿地变化监测方法

以玛多县为典型研究区,利用2010年Landsat TM数据比较分析了谱间关系法、归一化水体指数（NDWI）、修正归一化水体指数（MNDWI）及非监督分类4种分类方法提取湿地信息的准确度。结果表明,在较大显著湿地区域,4种方法信息提取的准确度都比较高;在海拔4 500 m以上且地形复杂地区,MNDWI方法的精度明显高于其他3种方法,达到86%;在中部地势较低区域,MNDWI方法不如NDWI方法的准确度高,但优于谱间关系法及非监督分类方法。总体来说,MNDWI方法能很好地将云和地形对湿地信息提取的影响降到最低,筛选最佳湿地信息提取方法有助于保护青藏高原湿地资源。     

曼陀罗对大豆的化感作用研究

采用室内生物测定方法,分别测定曼陀罗根、果皮、种子浸提液对大豆种子萌发、幼苗生长及若干生理指标的影响.结果表明,曼陀罗对大豆的化感效应存在不同供体器官的差异,总体表现为根＞果皮＞种子;受体器官所受到的抑制作用也存在差异,总体表现为侧根＞种子＞根.曼陀罗对大豆的化感效应随其浸提液的质量浓度提高而增强.其生理指标测定结果表明,曼陀罗对大豆幼苗可溶性蛋白的分解有较大的抑制作用.