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维持性血液透析患者监测频率与临床达标情况分析
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作者 张月 洪大情 +1 位作者 何强 王莉 《四川医学》 CAS 2013年第11期1666-1668,共3页
目的 指南推荐维持性血透患者(MHD)临床监测频率应每1~3月1次,提供临床指导和判断,而实际工作中检验频率和推荐频率有差异.本研究通过分析我中心临床指标实际监测频率与指标达标情况,了解它们之间的关系.方法 回顾性分析310例患者分... 目的 指南推荐维持性血透患者(MHD)临床监测频率应每1~3月1次,提供临床指导和判断,而实际工作中检验频率和推荐频率有差异.本研究通过分析我中心临床指标实际监测频率与指标达标情况,了解它们之间的关系.方法 回顾性分析310例患者分别行血常规、血电解质、ALB、iPTH等检查的次数,测定上述指标值,按照KDOQI及KDIGO指南计算每位患者1年间的达标率,分析患者临床检验的频率与上述指标达标情况的关系.结果 按患者各项检验的次数,将患者分为三组(A组,检验≤3次/年;B组,4~5次/年;C组,≥6次/年),三组患者年龄、性别、CKD病程及透析龄无显著差异.血Hgb,A组与B组、A组与C组差异有统计学意义(P〈0.05),B组与C组差异无统计学意义(P =0.793);Hgb达标率,A组与B组、A组与C组差异有统计学意义(P 〈0.01),而B组与C组患者Hgb达标率无显著差异.血Ca、P值达标率与Hgb类似,A组与B组、A组与C组差异有统计学意义,B组与C组差异无统计学意义.结论 指南推荐的检测频率有利于MHD患者各项指标的控制,临床上实施存在困难时应至少每季度一次,否则不利于贫血及钙磷等生化等指标的控制. 展开更多
关键词 血液透析 检验频率
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应用《公路工程质量检验评定标准》应注意的问题 被引量:8
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作者 于庆 《河北工业科技》 CAS 2002年第6期51-54,共4页
《公路工程质量检验评定标准》(JTJ0 71— 98)作为公路工程建设中必须严格执行的主要技术法规 ,在加强工程技术管理和质量监控方面起到了重要作用。本文将实际工作中应用该标准遇到的“检验项目允许偏差的极值”、“砼排水沟及钢筋砼沟... 《公路工程质量检验评定标准》(JTJ0 71— 98)作为公路工程建设中必须严格执行的主要技术法规 ,在加强工程技术管理和质量监控方面起到了重要作用。本文将实际工作中应用该标准遇到的“检验项目允许偏差的极值”、“砼排水沟及钢筋砼沟盖板标准无实测检查项目”和“实测项目的检验频率大于或小于标准要求”问题做了扼要阐述 ,并提出相应的解决方案。实践证明 ,这些方案对于正确理解和执行 JTJ0 71— 98标准 。 展开更多
关键词 《公路工程质量检验评定标准》 偏差极值 检验频率
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基于GARCH-GED分布模型的证券投资基金风险度量 被引量:10
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作者 鲁皓 周志凯 《金融理论与实践》 北大核心 2014年第3期8-11,共4页
随着基金行业改革的推进,市场风险日益成为证券投资基金面临的主要风险。基于收益率序列的波动聚集特征,在计算VaR时对方差-协方差法进行了改进:为描述分布的尖峰厚尾特性,假定其收益服从GED分布;为描述条件方差的时变性,将GARCH模型引... 随着基金行业改革的推进,市场风险日益成为证券投资基金面临的主要风险。基于收益率序列的波动聚集特征,在计算VaR时对方差-协方差法进行了改进:为描述分布的尖峰厚尾特性,假定其收益服从GED分布;为描述条件方差的时变性,将GARCH模型引入VaR计算,并以10只开放式基金为样本进行实证分析。结果表明:基于GARCH-GED模型的VaR方法比传统方法更有效,能够较好地刻画证券投资基金的市场风险。 展开更多
关键词 VAR 证券投资基金 GARCH模型 GED分布 失败频率检验
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基于HMM的VaR风险度量及其实证分析 被引量:3
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作者 汪金菊 吴燕飞 王杨 《合肥工业大学学报(自然科学版)》 CAS CSCD 北大核心 2013年第5期632-636,共5页
文章基于隐马尔科夫模型(HMM)提出了度量金融资产风险价值(VaR)的HMM-ARMA-GARCH模型。首先对金融资产收益率序列建立正常状态和异常状态的隐马尔科夫模型,使用期望最大化算法估算出模型中的未知参数,再利用Viterbi算法估算出收益率序... 文章基于隐马尔科夫模型(HMM)提出了度量金融资产风险价值(VaR)的HMM-ARMA-GARCH模型。首先对金融资产收益率序列建立正常状态和异常状态的隐马尔科夫模型,使用期望最大化算法估算出模型中的未知参数,再利用Viterbi算法估算出收益率序列所对应的隐状态序列,根据隐状态序列把收益率序列数据分成正常状态类序列和异常状态类序列2个大类,对2个状态类序列分别建立ARMA-GARCH模型来估算VaR。最后利用该模型和传统的ARMA-GARCH模型对上证企债指数进行了实证分析,采用Ku-piec失败频率检验法对VaR的准确性进行检验。实证结果表明,该模型的VaR计算方法具有较好的估计效果,能够有效地降低GARCH模型高估波动持续性的现象。 展开更多
关键词 隐马尔科夫模型 VaR风险价值 ARMA-GARCH模型 Kupiec失败频率检验
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脉冲变压器频响自动测试系统
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作者 徐静波 唐侃 《上海工程技术大学学报》 CAS 1999年第3期179-186,共8页
对脉冲变压器实现了频响特性自动测试。系统硬件有包含IEEE-488卡和PIO-12卡的微机及HP8751A网络分析仪。用TURBOPASCAL编制控制程序。系统的运用可以提高测试效率,满足测试误差的要求。该系统已成功地投入自动生产线运行。
关键词 脉冲变压器 频率响应检验 自动测试系统
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沪深300指数的VaR风险测量——基于历史模拟法和蒙特卡罗模拟法 被引量:9
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作者 高可佑 王潇怡 黄勇兵 《市场周刊》 2008年第3期90-91,共2页
VaR是目前金融市场风险测量的主流方法。本文基于历史模拟法和蒙特卡罗模拟法,以沪深300指数为研究对象,进行了VaR风险测量实证研究。研究发现,蒙特卡罗模拟法能够较好地覆盖实际损失,适于我国股票市场价格指数的风险度量。
关键词 VAR 历史模拟法 蒙特卡罗模拟法 失败频率检验
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基于HMM-GARCH模型的VaR方法及其在农业股市的应用 被引量:1
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作者 容兰兰 陈爽 冯茹 《应用数学进展》 2017年第6期768-780,共13页
文章利用隐马尔科夫模型在状态划分上的优势,将隐马尔科夫模型(HMM)与GARCH模型结合建立HMM-GARCH模型来度量金融资产风险价值(VaR)?首先对收益率序列建立隐马尔科夫模型,将股票市场分为正常状态与异常状态,用Baum-Welch算法估算模型的... 文章利用隐马尔科夫模型在状态划分上的优势,将隐马尔科夫模型(HMM)与GARCH模型结合建立HMM-GARCH模型来度量金融资产风险价值(VaR)?首先对收益率序列建立隐马尔科夫模型,将股票市场分为正常状态与异常状态,用Baum-Welch算法估算模型的参数,再采用Viterbi算法估算收益率序列所对应的隐状态序列,根据隐状态序列将收益率序列分为两类,分别建立HMM-GARCH模型估算VaR?最后利用GARCH模型?MRS-GARCH模型?HMM-GARCH模型对北大荒股票(600598)数据进行了实证分析,采用Kupiec-失败频率检验法对估计的VaR值进行检验?实证结果表明,基于HMM-GARCH模型的VaR方法能更好的描绘和预测该股票的风险? 展开更多
关键词 HMM-GARCH模型 MRS-GARCH模型 VAR方法 Kupiec-失败频率检验
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基于GARCH—VaR模型的人民币兑美元的汇率风险研究
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作者 余志鸿 吴学福 《经济视野》 2014年第11期306-307,共2页
本文以2006年1月1日至2013年10月31日人民币兑美元的中间汇率为样本数据,进行了计量检验,首先采用GARCH模型计算对数收益率的条件方差,其次运用V水方法中的参数法计算对数收益率的V水值,最后使用Kupiec检验法检验GARCH—VaR模型的... 本文以2006年1月1日至2013年10月31日人民币兑美元的中间汇率为样本数据,进行了计量检验,首先采用GARCH模型计算对数收益率的条件方差,其次运用V水方法中的参数法计算对数收益率的V水值,最后使用Kupiec检验法检验GARCH—VaR模型的有效性,实证研究表明运用GARcH—VaR模型研究汇率波动性有一定应用价值。 展开更多
关键词 汇率波动 GARCH模型 失败频率检验
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关于随机变量相关性的几个问题
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作者 刘珍儒 刘群生 《山东理工大学学报(自然科学版)》 CAS 1994年第2期6-11,共6页
本文主要研究了两随机变量“函数相关”和“相互独立”的充要条件;揭示了相关系数的几何意义;得到了对多元非线性回归函数拟合检验的一种新方法——频率拟合检验法。
关键词 相关系数 函数相关 频率拟和检验
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Risk modification of colorectal cancer susceptibility by interleukin-8-251T>A polymorphism in Malaysians 被引量:6
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作者 Mohd Aminudin Mustapha Siti Nurfatimah Mohd Shahpudin +1 位作者 Ahmad Aizat Abdul Aziz Ravindran Ankathil 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第21期2668-2673,共6页
AIM: To investigate the allele and genotype frequencies and associated risk of interleukin (IL)-8-251T>A polymorphism on colorectal cancer (CRC) susceptibility risk. METHODS: Peripheral blood samples of 255 normal ... AIM: To investigate the allele and genotype frequencies and associated risk of interleukin (IL)-8-251T>A polymorphism on colorectal cancer (CRC) susceptibility risk. METHODS: Peripheral blood samples of 255 normal controls and 255 clinically and histopathologically confirmed CRC patients were genotyped for IL-8-251T>A polymorphism employing allele-specific polymerase chain reaction. The relative association of variant allele and genotypes with CRC susceptibility risk was determined by calculating the odds ratios (ORs). Corresponding χ 2 tests on the CRC patients and controls were carried out and 95% confidence intervals (CIs) were determined using Fisher's exact test. The allele frequencies and its risk association were calculated using FAMHAP, haplotype association analysis software. RESULTS: On comparing the frequencies of genotypesof patients and controls, the homozygous variant AA was significantly higher in CRC patients (P = 0.002) compared to controls. Investigation on the association of the polymorphic genotypes with CRC susceptibility risk, showed that the homozygous variant IL-8 -251AA had a significantly increased risk with OR 3.600 (95% CI: 1.550-8.481, P = 0.001). In the case of allele frequencies, variant allele A of IL-8 -251 showed a significantly increased risk of CRC predisposition with OR 1.32 (95% CI: 1.03-1.69,P = 0.003). CONCLUSION: Variant allele and genotype of IL-8 (-251 T>A) was significantly associated with CRC susceptibility risk and could be considered as a high-risk variant for CRC predisposition. 展开更多
关键词 Interleukin-8-251T〉A Polymorphism Colorectal cancer Malaysians
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Eosinophil associated genes in the inflammatory bowel disease 4 region:Correlation to inflammatory bowel disease revealed
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作者 Kristin Blom Jenny Rubin +9 位作者 Jonas Halfvarson Leif Trkvist Anders Rnnblom Per Sangfelt Mikael Lrdal Ulla-Britt Jnsson Urban Sjqvist Lena Douhan Hkansson Per Venge Marie Carlson 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第44期6409-6419,共11页
AIM: To study the association between inflammatory bowel disease (IBD) and genetic variations in eosinophil protein X (EPX) and eosinophil cationic protein (ECP). METHODS: DNA was extracted from ethylene diami... AIM: To study the association between inflammatory bowel disease (IBD) and genetic variations in eosinophil protein X (EPX) and eosinophil cationic protein (ECP). METHODS: DNA was extracted from ethylene diamine tetraacetic acid blood of 587 patients with Crohn's disease (CD), 592 with ulcerative colitis (UC) and 300 healthy subjects. The EPX405 (G 〉 C, rs2013109), ECP434 (G 〉 C, rs2073342) and ECP562 (G 〉 C, rs2233860) gene polymorphisms were analysed, by the 5'-nuclease allelic discrimination assay. For de- termination of intracellular content of EPX and ECP in granulocytes, 39 blood samples was collected and extracted with a buffer containing cetyltrimethylam- monium bromide. The intracellular content of EPX was analysed using an enzyme-linked immunosorbent as- say. The intracellular content of ECP was analysed with the UniCAP system as described by the manufacturer. Statistical tests for calculations of results were χ2 test, Fisher's exact test, ANOVA, Student-Newman-Keuls test, and Kaplan-Meier survival curve with Log-rank test for trend, the probability values of P 〈 0.05 were considered statistically significant.RESULTS: The genotype frequency for males with UC and with an age of disease onset of ≥ 45 years (n = 57) was for ECP434 and ECP562, GG = 37%, GC = 60%, CC = 4% and GG = 51%, GC = 49%, CC = 0% respectively. This was significantly different from the healthy subject's genotype frequencies of ECP434 (GG = 57%, GC = 38%, CC = 5%; P = 0.010) and ECP562 (GG = 68%, GC = 29%,CC = 3%; P = 0.009). The genotype frequencies for females, with an age of dis- ease onset of ≥ 45 years with CD (n = 62), was for the ECP434 and ECP562 genotypes GG = 37%, GC =52%, CC = 11% and GG = 48%, GC = 47% and CC = 5% respectively. This was also statistically different from healthy controls for both ECP434 (P = 0.010) and ECP562 (P = 0.013). The intracellular protein concen- tration of EPX and ECP was calculated in μg/10^6 eosi- nophils and then correlated to the EPX 405 genotypes. The protein content of EPX was highest in the patients with the CC genotype of EPX405 (GG = 4.65, GC = 5.93, and CC = 6.57) and for ECP in the patients with the GG genotype of EPX405 (GG = 2.70, GC = 2.47 and CC = 1.90). ANOVA test demonstrated a difference in intracellular protein content for EPX (P = 0.009) and ECP (P = 0.022). The age of disease onset was linked to haplotypes of the EPX405, ECP434 and ECP562 genotypes. Kaplan Maier curve showed a difference be- tween haplotype distributions for the females with CD (P = 0.003). The highest age of disease onset was seen in females with the EPX405CC, ECP434GC, ECP562CC haplotype (34 years) and the lowest in females with the EPX405GC, ECP434GC, ECP562GG haplotype (21 years). For males with UC there was also a difference between the highest and lowest age of the disease on- set (EPX405CC, ECP434CC, ECP562CC, mean 24 years vs EPX405GC, ECP434GC, ECP562GG, mean 34 years, P = 0.0009). The relative risk for UC patients with ECP434 or ECP562-GC/CC genotypes to develop dys- plasia/cancer was 2.5 (95%CI: 1.2-5.4, P = 0.01) and 2.5 (95%CI: 1.1-5.4, P = 0.02) respectively, compared to patients carrying the GG-genotypes. 展开更多
关键词 Eosinophil derived neurotoxin RNase 2 RNase 3 Single nucleotide polymorphism Inflamma-tion bowel disease Crohn's disease Ulcerative colitis
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Hypothesis testing analysis and unknown parameter estimation of GPS signal detection 被引量:3
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作者 张文 M.Ghogho 《Journal of Central South University》 SCIE EI CAS 2012年第5期1290-1301,共12页
Hypothesis testing analysis and unknown parameter estimation of both the intermediate frequency(IF) and baseband GPS signal detection are given by using the generalized likelihood ratio test(GLRT) approach,applying th... Hypothesis testing analysis and unknown parameter estimation of both the intermediate frequency(IF) and baseband GPS signal detection are given by using the generalized likelihood ratio test(GLRT) approach,applying the model of GPS signal in white Gaussian noise,It is proved that the test statistic follows central or noncentral F distribution,It is also pointed out that the test statistic is nearly identical to central or noncentral chi-squared distribution because the processing samples are large enough to be considered as infinite in GPS acquisition problem.It is also proved that the probability of false alarm,the probability of detection and the threshold are affected largely when the hypothesis testing refers to the full pseudorandom noise(PRN) code phase and Doppler frequency search space cells instead of each individual cell.The performance of the test statistic is also given with combining the noncoherent integration. 展开更多
关键词 global positioning system (GPS) signal detection parameter estimation generalized likelihood ratio test (GLRT) probability of false alarm probability of detection THRESHOLD
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The MNS16A polymorphism in the TERT gene in peri-centenarians from the Han Chinese population 被引量:1
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作者 LIU LiNa WANG ChengYe +5 位作者 LU Xiang XIAO FuHui WANG HuaWei YANG LiQin XU LiangYou KONG QingPeng 《Science China(Life Sciences)》 SCIE CAS 2014年第10期1024-1027,共4页
MNS16A, a variable number of tandem repeats polymorphism in the TERT gene, has been suggested to regulate telomerase activity. As telomerase activity has been reported to be related to life-span, we hypothesized that ... MNS16A, a variable number of tandem repeats polymorphism in the TERT gene, has been suggested to regulate telomerase activity. As telomerase activity has been reported to be related to life-span, we hypothesized that this polymorphism might affect human longevity by controlling the length of the telomere. To test this hypothesis, we collected 446 unrelated pericentenarian individuals (age)90, mean 94.45±3.45 years) and 332 normal controls (age 22-53, mean 35.0±12.0 years) from Dujiangyan, Sichuan, China. We typed the MNS16A polymorphism in both groups, and compared the allele and genotype frequencies between the peri-centenarian and control groups using the chi-squared test. There was no significant difference between the peri-centenarian and control groups. Thus, the MNS16A polymorphism in TERT might not influence human life-span, at least in the Hart Chinese population studied here. 展开更多
关键词 TELOMERASE LONGEVITY MNS16A polymorphism peri-centenarian
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