关系数据库中关系模式的规范化   总被引：1，自引：0，他引：1  

佘学兵  饶苏敏 《科技广场》2008,(10)

关系数据库中的关系模式直接影响了数据库中数据的完整性、准确性和一致性,好的关系模式能避免数据冗余和操作异常。关系规范化是设计关系模式的依据,是围绕函数依赖进行的。其基本思想是一个关系只描述一个主题,遵从"一事一地"原则,不能把彼此没有直接关联的属性放在一起,这将会导致关系数据库性能变坏。关系规范化过程是不断分解关系的过程。根据关系中属性间函数依赖情况规定了若干标准,这就是所谓的1NF、2NF和3NF,还有更高的范式,通常认为3NF在性能、扩展性和数据完整性方面都达到了最好的平衡,故一般关系模式设计要求达到3NF。  相似文献   

转型时期图书馆知识产权管理战略需求、目标与路径   总被引：7，自引：0，他引：7  

陈传夫  饶艳  吴钢 《中国图书馆学报》2010,36(2)

我国各类型图书馆正处在战略转型状态,这种转型的特征是数字资源的开发利用、本地服务与远程服务融合、图书馆服务与图书馆资源融合、图书馆与社区融合、图书馆权威服务与联盟合作,等等.知识产权管理是实现图书馆转型的关键问题之一.文章在调研基础上,对转型时期图书馆知识产权战略需求、战略重点、战略路径等进行探讨,提出运用知识产权推进我国图书馆战略转型的理论观点.  相似文献   

Association of hyperhomocysteinemia to alcohol withdrawal in chronic alcoholics     

K. Devika Rani  N. Suneetha  Shruti Mohanty  Pragna Rao 《Indian journal of clinical biochemistry : IJCB》2008,23(2):150-153

This study is conducted in chronic alcoholics to assess the association of an Individual’s level of serum homocysteine with the success of achieving alcohol deaddiction in the patient. The patients’ nutrition status is also assessed. 50 chronic alcoholics admitted to a deaddiction center were inducted into the study. Patients underwent an 8 weeks holistic program to promote rehabilitation from alcoholism. All the patients were addicted to alcohol for 8 – 10 years. Of the 50 patients enrolled, 39 of them completed the 8 weeks program including complete abstinence from alcohol during this period. Fasting blood samples were collected on admission and again after 8 weeks of alcohol abstinence for analyses of serum homocysteine and serum prealbumin, transferrin, total proteins and albumin, gammaglutamyl transferase (GGT) and alanine transaminase (ALT). Of the 50 patients enrolled in the study, 39 completed the 8 weeks rehabilitation program. 11 patients discontinued within 2 weeks of admission. During the 8 weeks of complete alcohol abstinence, patients were given a balanced diet and multivitamin supplements. A significant improvement in their nutritional status was noted by the elevation of serum levels of prealbumin, transferrin, total proteins and albumin. Serum homocysteine levels decreased significantly (p<0.002) to normal levels from previous hyperhomocytenemia. This was accompanied by decrease in serum GGT and ALT levels indicating improved liver functions. Serum estimation of homocysteine in chronic alcoholics is important to assess whether the patient will have a successful rehabilitation. Normal homocysteine levels are achieved after dietary changes and abstinence from alcohol. Timely correction of hyperhomocysteinemia also provides successful rehabilitation.  相似文献   

樱桃属种间杂种的早期分子鉴定     

王鸿霞  叶乃好  李文生  张开春  束怀瑞 《中国科学院大学学报》2006,23(5):671-675

通过剥蕾反复授粉克服欧洲甜樱桃与毛樱桃种间杂交障碍,采用胚培养的方法克服了远缘杂种在自然状态下胚败育的情况发生,获得了以甜樱桃先锋为母本,以毛樱桃为父本的杂种G3。本实验利用AS-PCR技术将S等位基因作为樱桃砧木辅助育种中的分子标记,对获得的远缘杂种在苗期进行S基因型鉴定,结果表明G3的确是远缘杂交的新种质,RAPD分析显示G3同时具有母本和父本的特征随机扩增DNA片段,进一步证实了AS-PCR方法的可靠性。通过远缘杂交的育种能够有效的扩展樱桃砧木的遗传背景,另一方面利用分子标记的手段在苗期即可进行预先选择和鉴定。  相似文献   

关于我国钢铁工业发展的思考     

饶文涛 《中国科技论坛》2000,(4):12-14,18

1996年我国粗钢产量首次突破1亿吨,产量跃居当年的世界第一,在我国的冶金史上树立了一块里程碑,圆了多年国人要把中国变为钢铁大国的梦.最近三四年我国已经扭转了从建国以来就一直存在的钢铁供应紧缺的局面,供和需转为大体平衡,钢铁进一步增产的紧迫性已不如从前,但这并不等于市场对钢铁的需求不会随着国民经济的发展进一步增长,事实上,尽管这几年钢铁的供需矛盾趋于缓和,但无论需求和生产仍是逐年增长的,只是增长的幅度不如前几年大.在面临世纪之交,对我国钢铁工业的发展进行分析,找出未来发展的方向是非常必要的.  相似文献   

New age adjuvants and delivery systems for subunit vaccines     

Sridevi Kurella  Monika Manocha  Leenu Sabhnani  Beena Thomas  D. N. Rao 《Indian journal of clinical biochemistry : IJCB》2000,15(1):83-100

The dramatic advancements in the field of vaccinology has led to the formulation of chemically well defined vaccines composed of synthetic peptides and recombinant proteins derived from the immunologically dominant regions of the pathogens. Though these subunit vaccines are safer compared to the traditional vaccines they are known to be poorly immunogenic. This necessitates the use of adjuvants to enhance the immunogenicity of these vaccine formulations. The most common adjuvant for human use is alum. Research in the past has focused on the development of systemic immunity using conventional immunization protocols. In the present are, the emphasis is on the development and formulation of alternative adjuvants and delivery systems in generating systemic as well as mucosal immunity. This review mainly focuses on a variety of adjuvants (particulate as well as non-particulate) used with protective antigens of HIV, malaria, plague, leprosy using modified delivery vehicles. The experience of our laboratory and other researchers in this field clearly proves that these new age adjuvants and delivery systems undoubtedly generate enhanced immune response-both humoral and cell mediated. The choice of antigens, the nature of adjuvant used and the mode of delivery employed have a profound effect on the type of immune response generated. Besides the quantity, the quality of the antibodies generated also play a vital role in protection against these diseases. Some of the adjuvants and delivery systems used promoted high titre and affinity antibodies, which were shown to be cytophilic in nature, an important criteria in providing protection to the host. Thus the studies on these adjuvants/delivery systems with respect to various infectious diseases indicate their active role in efficient modulation of immune response along with safety and permissibility.  相似文献   

Studies on some serum enzyme levels in various liver diseases     

D. S. Raghavendra  Shrinivas B. Rao 《Indian journal of clinical biochemistry : IJCB》2000,15(1):48-51

Serum alkaline phosphatase (ALP) (EC 3.1.3.1), 5′nucleotidase (5′NT) (EC 3.1.3.5), aldolase (ALD) (EC 4.1.2.13) and sorbitol dehydrogenase (SDH) (EC 1.1.1.14) were estimated in infective hepatitis, alcoholic hepatitis, chronic active hepatitis, obstructive jaundice, cirrhosis of liver and amoebic liver abscess. It was observed that serum ALP and 5′NT were significantly increased in all cases of chronic active hepatitis and obstructive hepatic disease. However, the elevation observed in the latter was much higher than the former. Serum SDH and ALD levels were elevated in all cases of infective hepatitis, studied though increase in the former was much higher than the latter, suggesting its significance in the diagnostic confirmation of this disease. Results presented suggest 5′NT and SDH as more reliable diagnostic test compared to ALP and ALD for obstructive jaundice and infective hepatitis respectively.  相似文献   

Intelligent Indexing and Semantic Retrieval of Multimodal Documents   总被引：2，自引：0，他引：2  

Rohini K. Srihari  Zhongfei Zhang  Aibing Rao 《Information Retrieval》2000,2(2-3):245-275

Finding useful information from large multimodal document collections such as the WWW without encountering numerous false positives poses a challenge to multimedia information retrieval systems (MMIR). This research addresses the problem of finding pictures. The fact that images do not appear in isolation, but rather with accompanying, collateral text is exploited. Taken independently, existing techniques for picture retrieval using (i) text-based and (ii) image-based methods have several limitations. This research presents a general model for multimodal information retrieval that addresses the following issues: (i) users' information need, (ii) expressing information need through composite, multimodal queries, and (iii) determining the most appropriate weighted combination of indexing techniques in order to best satisfy information need. A machine learning approach is proposed for the latter. The focus is on improving precision and recall in a MMIR system by optimally combining text and image similarity. Experiments are presented which demonstrate the utility of individual indexing systems in improving overall average precision.  相似文献   

"全程情境教学法"在《国际贸易实务》课程教学中的实践与探索   总被引：2，自引：0，他引：2  

蔡环宇  饶华 《科技广场》2007,(8):161-162

课堂教学是高等教育教学体系中的重要组成部分,针对《国际贸易实务》课程实践性和操作性很强的特点,运用一种全程情境教学法,并分析和探讨了该方法的实践过程、特点及其实施条件。  相似文献   

Think it over     

Photon Rao 《Resonance》1996,1(3):115-115

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