基于数字水印技术和多媒体内容认证的交易协议

基于数字水印技术和多媒体内容认证技术,提出买卖双方交互协议。该协议可以明确确认交易双方的身份,有效地防止了购买者水印被盗用的可能性,并很容易判定所购得的数字产品是否被篡改。     

高校图书馆读者资源开发及应用

阐述高校图书馆读者资源的重要性,分析读者资源的类型及其与传统资源相比拥有的特点,根据高校图书馆的两大读者资源,分别阐述怎样开发及应用教师资源和学生资源,探究读者资源可持续开发应用的有效措施。     

Effect of K-diformate in starter diets on acidity, microbiota, and the amount of organic acids in the digestive tract of piglets, and on gastric alterations

The aim of this investigation was to study the effect of K-diformate on the intraluminal pH, microbial composition in digesta and feces, organic acids along the digestive tract, and alterations of the gastric epithelium of pigs. Pigs (n = 36) weaned at 28 d of age were allotted to two groups and fed without (control diet) or with 1.8% supplemental K-diformate. Fecal samples were taken from the rectum on d 0, 1, 3, 5, 7, 14, 21, and 28 postweaning. Half of the animals from each group were killed on d 7 and the other half on d 29 postweaning. Growth performance was not different for both groups (P > or = 0.73). The gastric epithelium was not negatively affected by K-diformate (P = 0.25). Potassium-diformate decreased (P < or = 0.04) or tended to decrease (P < or = 0.10) the counts of total anaerobic bacteria, lactic acid bacteria, and yeasts in feces and digesta samples from the stomach, distal small intestine, cecum, and middle segment of the colon. The pH along the gastrointestinal tract of piglets was not affected by K-diformate (P > or = 0.30). On d 7, the concentration of lactic acid along the gastrointestinal tract was similar with both diets (P = 0.15). On d 29, the concentrations of lactic acid tended to be lower along the small intestine (P < or = 0.08) and the stomach (P = 0.11) of the pigs fed K-diformate. Formic acid in digesta was detected at significant levels only in the distal segment of the small intestine of the control pigs (from 4 to 11 mmol/kg of wet digesta), whereas considerable amounts were measured in the stomach (from 23 to 40 mmol/kg of wet digesta) and all segments of the small intestine (from 7 to 25 mmol/kg of wet digesta) in the K-diformate-fed pigs on both days. On d 7, pigs fed the K-diformate diet had a tendency (P < or = 0.08) to have higher concentrations of organic acids (acetic + propionic + butyric) in the digesta of the distal small intestine, cecum, and proximal colon. On d 29, both groups had similar concentrations of these acids, irrespective of the segment of the gastrointestinal tract (P = 0.95). Our study showed that the addition of K-diformate to a starter diet for piglets decreased total anaerobic bacteria, lactic acid bacteria, coliforms, and yeasts in feces and in digesta from various segments of the gastrointestinal tract, without affecting the gastric or intestinal pH.     

Development of intervertebral disk calcification in the dachshund: a prospective longitudinal radiographic study

Plain spinal radiography was performed in 40 dachshunds at regular intervals from 6 or 12 months of age to 2 years of age. A follow-up study at 3 to 4 years of age included 12 dogs. High incidence rates of intervertebral disk calcification were seen at 6 to 18 months of age. The number of dogs affected and number of calcified disks seemed to reach a steady level or a maximum at about 24 to 27 months of age. Dissolution of previously calcified disks without clinical signs was demonstrated, causing decreasing numbers of visibly calcified disks after 2 years of age. Radiographic examination for calcified intervertebral disks in the dachshund is recommended at 24 to 30 months of age for heritability studies and selective breeding.     

The Use of a GUS Transformant of Trichoderma Harzianum, Strain T3a, to Study Metabolic Activity in the Spermosphere and Rhizosphere Related to Biocontrol of Pythium Damping-off And Root Rot

The activity of Trichoderma harzianum in the spermosphere and rhizosphere of different plant species was studied by use of a beta-glucuronidase (GUS) transformant (strain T3a). Hereby, direct observation of micro-habitats supporting metabolic activity of T. harzianum is reported. Germination of conidia and mycelial growth were not supported by exudates from healthy roots of various ages. Instead, growth and activity of T. harzianum depended on access to dead organic substrates such as seed coats, decaying roots, and wounds, including those caused by infecting pathogens. A correlation between the GUS activity of T. harzianum and the biomass of Pythium ultimum in infected roots was established. On the basis of our observations, we suggest that the biocontrol ability of T. harzianum involves competition with the pathogen for substrates including the seed coat, and wounded or infected root tissue.     

旱作春小麦品种高产抗旱特性的综合评价

对引进的旱作春小麦品种（系）做小区试验，初步筛选出C160和8275两个抗旱性强产量高的品种（系）。其叶面积变化表现为峰值出现早、大小适中，后期能保持较高叶面积。通过生理指标测定，在干旱条件下，这两个品种（系）均表现为叶绿素高、叶片相对含水量多、脯胺酸积累增加、叶水势加大、细胞膜的相对透性减少等特征，是较抗旱的表现，运用模糊综合评判法将各种的产量、与产量相关的性状和生理指标结合在一起进行综合评价，对品种优劣进行排序，其顺序为：C160，8275，8139，8624，8338，定西35，C4，昌春3号，会宁17。     

Auscultation in mild mitral regurgitation in dogs: observer variation, effects of physical maneuvers, and agreement with color Doppler echocardiography and phonocardiography

Observer variation in diagnosing mild mitral regurgitation in dogs by cardiac auscultation was assessed by having 6 veterinarians with different levels of experience examine 57 Cavalier King Charles Spaniels. Comparisons with color Doppler echocardiography and phonocardiography were made, and the effects of 2 physical maneuvers on the auscultatory findings were evaluated. Using mildly diseased dogs, interobserver agreement in diagnosing the presence or absence of left-sided murmurs ranged from 63% to 88%. The agreement with phonocardiography (range, 53-91%) increased with the amount of observer experience. The 2 most experienced observers could discern soft ejection murmurs from regurgitant murmurs and were able to diagnose 89% of the dogs with regurgitant jets larger than 30% of the left atrial area. In general, less experienced observers diagnosed most jets larger than 50%. In many dogs with small jets, no murmur was found by auscultation and phonocardiography. The audibility of mild regurgitation was significantly reduced in dogs that were difficult to auscultate. Early systolic murmurs were typical of mild regurgitation, whereas holosystolic murmurs typified severe regurgitation. In a few dogs, late systolic murmurs alternated with holosystolic murmurs. Systolic clicks were found phonocardiographically in 18 dogs with mild to moderate regurgitation, but the audibility apparently was low. In many mildly affected dogs, physical maneuvers increased murmur intensity. Thus, some form of dynamic auscultation might facilitate the diagnosis of mild regurgitation. Auscultatory findings in mild regurgitation appear to depend on observer experience, circulatory status, and how difficult the dog is to auscultate.     

Initial lung lesions in two calves experimentally infected with Haemophilus somnus

The initial lung lesions in two calves intrabronchially inoculated with Haemophilus somnus are described. The animals were euthanized within 7 h after challenge. The in situ location of H. somnus and accompanying lesions were examined by light microscopy, immunohistochemistry and transmission electron microscopy (TEM). Inoculation with H. somnus resulted in the development of acute pulmonary lesions within 3.5 h. H. somnus antigen was demonstrated only within the luminal spaces of the airways and in one area of bronchio-associated lymphoid tissue (BALT). As observed by TEM, the bacteria were phagocytized by both neutrophils and alveolar macrophages. Antigen was never demonstrated in the pulmonary intravascular macrophages.     

中国与欧美农业科技创新体系对比研究

农业科技创新发展已成为推动现代农业发展的重要原动力。近年来,中国步入农业科技创新发展的快车道,为探寻建立健全中国农业科技创新体系的路径与方法,对美国、英国、德国与中国的农业科技创新体系进行对比。结果表明：①农业产业的特殊性决定农业科技创新体系的特殊性,农业科技创新主体、农业科技创新环境、农业科技创新成果与应用、农业科技创新国际合作相互作用,构成完整的农业科技创新体系。②产学研紧密结合是美国农业科技创新体系的突出特点,英国则是注重政府引导、信息共享与知识服务,德国是信息化生态型农业科技创新体系代表,注重信息引领与绿色、可持续发展。③与欧美农业科技创新体系相比,我国农业科技创新体系仍存在一些不足,未来可从协调统筹、规划建设、队伍与机制建设等方面入手,全面推动我国农业科技创新体系发展建设。     

Effect of infection by bovine viral diarrhea virus (BVDV) in vitro on interleukin-1 activity of bovine monocytes

The effect of bovine viral diarrhea virus (BVDV) infection in vitro on the interleukin-1 (IL-1) activity of bovine monocytes was studied. Supernatants from BVDV-infected monocytes suppressed IL-1-stimulated proliferation of mouse thymocytes and masked lipopolysaccharide-stimulated IL-1 activity of bovine monocytes in the mouse comitogen thymocyte assay. Suppression of mouse thymocyte proliferation was restored by the addition of IL-1. IL-1 inhibitory activity was induced both by the prototype variants BVDV/NADL cytopathic and BVDV/NY-1 noncytopathic and by BVDV variants isolated from persistently infected cattle. Suppressed IL-1 activity was also found in supernatants from monocytes from persistently infected cattle following infection with BVDV in vitro. No differences in levels of IL-1 mRNA synthesis were detected between BVDV-infected and uninfected monocytes by RNA-cDNA hybridization. These results suggest that infection of bovine monocytes with BVDV results in the production and/or activation of a soluble inhibitor of IL-1 activity.