分析了面向先进硬件平台上的数据库优化技术,提出了基于内存存储模型的多表连接查询处理优化技术,采用内存存储模型存储维表并对维表主键进行顺序化,从而使维表的主键与内存维表记录的内存偏移地址相一致,实现对维表记录的内存直接访问...分析了面向先进硬件平台上的数据库优化技术,提出了基于内存存储模型的多表连接查询处理优化技术,采用内存存储模型存储维表并对维表主键进行顺序化,从而使维表的主键与内存维表记录的内存偏移地址相一致,实现对维表记录的内存直接访问。通过列存储技术减少维表记录的访问宽度,进一步优化维表访问的cache性能。与基于SQL Server 2005的查询执行计划的连接算法、join index连接算法以及基于列存储模型的优化连接算法进行了实验比较和性能分析,结果表明:基于内存存储模型的多表连接算法在处理星型结构数据仓库多谓词、多连接的复杂查询时具有很好的性能,与join index相比不需要额外的空间开销,与列存储数据模型相比具有更好的兼容性和性能。展开更多
Outpatient percutaneous liver biopsy is a common practice in the differential diagnosis and treatment of chronic liver disease. The major complication and mortality rate were about 2-4% and 0.01-0.33% respectively. Ar...Outpatient percutaneous liver biopsy is a common practice in the differential diagnosis and treatment of chronic liver disease. The major complication and mortality rate were about 2-4% and 0.01-0.33% respectively. Arterio-portal fistula as a complication of percutaneous liver biopsy was infrequently seen and normally asymptomatic. Hemobilia, which accounted for about 3% of overall major percutaneous liver biopsy complications, resulted rarely from arterio-portal fistula We report a hemobilia case of 68 years old woman who was admitted for abdominal pain after liver biopsy. The initial ultrasonography revealed a gallbladder polypoid tumor and common bile duct (CBD) dilatation. Blood clot was extracted as endoscopic retrograde cholangiopancreatography (ERCP) showed hemobilia. The patient was shortly readmitted because of recurrence of symptoms. A celiac angiography showed an intrahepatic arterio-portal fistula. After superselective embolization of the feeding artery, the patient was discharged uneventfully. Most cases of hemobilia caused by percutaneous liver biopsy resolved spontaneously. Selective angiography embolization or surgical intervention is reserved for patients who failed to respond to conservative treatment.展开更多
Carbon emissions embodied in international trade of China during 1997-2007 are accounted by input-output method based on Chinese input-output table and global trade analysis project database.It is revealed that carbon...Carbon emissions embodied in international trade of China during 1997-2007 are accounted by input-output method based on Chinese input-output table and global trade analysis project database.It is revealed that carbon emissions embodied in imports and exports both increased during 1997-2007,but carbon emissions embodied in exports are greater than those embodied in imports,China is a net export nation in embodied carbon.The net exports of embodied carbon account for about 10.82%of the total carbon emissions in 1997,dropped to 7.15%in 2002,increased to 13.13%in 2006,and slightly dropped to 12.64%in 2007.Low-end position of international industry division is an objective factor of being a net exporter of embodied carbon for China,and usage of a large amount of obsolete energy-using equipments wasted much energy and increased carbon emissions embodied in exports. Importers should take more responsibilities for carbon emissions embodied in trade,and China should take a certain responsibility for unreasonable energy dissipations too.展开更多
Using input-output tables of China and the U.S., this paper has calculated the pollution embodied in trade and structure of pollution, the balance of emissions embodied in trade （BEET） and the pollution terms of tra...Using input-output tables of China and the U.S., this paper has calculated the pollution embodied in trade and structure of pollution, the balance of emissions embodied in trade （BEET） and the pollution terms of trade （PTT） for 18 manufacturing sectors of China and the US. between 2001 and 2010. The calculation aims to verify whether China has become a ＂pollution haven＂ in bilateral trade with developed countries represented by the U.S., and whether Chinese exports are ＂dirtier＂ compared with imports from the U.S., and further conducting an industry structure analysis and effect decomposition study on pollution embodied in trade in industrial goods between China and U.S.. Result of our research indicates that according to our calculation of the BEET, China remains a country with environmental deficits in bilateral trade with the U.S. while the gaps between pollution embodied in China＇s export and import are narrowing. Pollution embodied in China＇s export has the tendency of increase before decline while pollution embodied in import demonstrates no significant tendency of decline. Through effect decomposition, we further found that the effect of technology arising from the substantial decline of pollution intensity effectively lowered pollution embodied in export and narrowed the environmental deficits of China in its bilateral trade. The effect of scale arising from growing export volumes significantly increased China＇s environmental deficits while the structural effect arising from changes in the structure of import and export is insignificant in reducing environmental deficits. Our calculation of the PTT led to the finding that China＇s export goods are more pollution intensive compared with import goods and that the structure of US exports to China is cleaner than the structure of Chinese exports to the US., which requires further improvements of China＇s import and export structure.展开更多
文摘分析了面向先进硬件平台上的数据库优化技术,提出了基于内存存储模型的多表连接查询处理优化技术,采用内存存储模型存储维表并对维表主键进行顺序化,从而使维表的主键与内存维表记录的内存偏移地址相一致,实现对维表记录的内存直接访问。通过列存储技术减少维表记录的访问宽度,进一步优化维表访问的cache性能。与基于SQL Server 2005的查询执行计划的连接算法、join index连接算法以及基于列存储模型的优化连接算法进行了实验比较和性能分析,结果表明:基于内存存储模型的多表连接算法在处理星型结构数据仓库多谓词、多连接的复杂查询时具有很好的性能,与join index相比不需要额外的空间开销,与列存储数据模型相比具有更好的兼容性和性能。
文摘Outpatient percutaneous liver biopsy is a common practice in the differential diagnosis and treatment of chronic liver disease. The major complication and mortality rate were about 2-4% and 0.01-0.33% respectively. Arterio-portal fistula as a complication of percutaneous liver biopsy was infrequently seen and normally asymptomatic. Hemobilia, which accounted for about 3% of overall major percutaneous liver biopsy complications, resulted rarely from arterio-portal fistula We report a hemobilia case of 68 years old woman who was admitted for abdominal pain after liver biopsy. The initial ultrasonography revealed a gallbladder polypoid tumor and common bile duct (CBD) dilatation. Blood clot was extracted as endoscopic retrograde cholangiopancreatography (ERCP) showed hemobilia. The patient was shortly readmitted because of recurrence of symptoms. A celiac angiography showed an intrahepatic arterio-portal fistula. After superselective embolization of the feeding artery, the patient was discharged uneventfully. Most cases of hemobilia caused by percutaneous liver biopsy resolved spontaneously. Selective angiography embolization or surgical intervention is reserved for patients who failed to respond to conservative treatment.
文摘Carbon emissions embodied in international trade of China during 1997-2007 are accounted by input-output method based on Chinese input-output table and global trade analysis project database.It is revealed that carbon emissions embodied in imports and exports both increased during 1997-2007,but carbon emissions embodied in exports are greater than those embodied in imports,China is a net export nation in embodied carbon.The net exports of embodied carbon account for about 10.82%of the total carbon emissions in 1997,dropped to 7.15%in 2002,increased to 13.13%in 2006,and slightly dropped to 12.64%in 2007.Low-end position of international industry division is an objective factor of being a net exporter of embodied carbon for China,and usage of a large amount of obsolete energy-using equipments wasted much energy and increased carbon emissions embodied in exports. Importers should take more responsibilities for carbon emissions embodied in trade,and China should take a certain responsibility for unreasonable energy dissipations too.
基金supported by the Foundation of Tianjin Educational Committee(Grant No.20112401)
文摘Using input-output tables of China and the U.S., this paper has calculated the pollution embodied in trade and structure of pollution, the balance of emissions embodied in trade （BEET） and the pollution terms of trade （PTT） for 18 manufacturing sectors of China and the US. between 2001 and 2010. The calculation aims to verify whether China has become a ＂pollution haven＂ in bilateral trade with developed countries represented by the U.S., and whether Chinese exports are ＂dirtier＂ compared with imports from the U.S., and further conducting an industry structure analysis and effect decomposition study on pollution embodied in trade in industrial goods between China and U.S.. Result of our research indicates that according to our calculation of the BEET, China remains a country with environmental deficits in bilateral trade with the U.S. while the gaps between pollution embodied in China＇s export and import are narrowing. Pollution embodied in China＇s export has the tendency of increase before decline while pollution embodied in import demonstrates no significant tendency of decline. Through effect decomposition, we further found that the effect of technology arising from the substantial decline of pollution intensity effectively lowered pollution embodied in export and narrowed the environmental deficits of China in its bilateral trade. The effect of scale arising from growing export volumes significantly increased China＇s environmental deficits while the structural effect arising from changes in the structure of import and export is insignificant in reducing environmental deficits. Our calculation of the PTT led to the finding that China＇s export goods are more pollution intensive compared with import goods and that the structure of US exports to China is cleaner than the structure of Chinese exports to the US., which requires further improvements of China＇s import and export structure.
