We explore the techniques of utilizing N gram information to categorize Chinese text documents hierarchically so that the classifier can shake off the burden of large dictionaries and complex segmentation process...We explore the techniques of utilizing N gram information to categorize Chinese text documents hierarchically so that the classifier can shake off the burden of large dictionaries and complex segmentation processing, and subsequently be domain and time independent. A hierarchical Chinese text classifier is implemented. Experimental results show that hierarchically classifying Chinese text documents based N grams can achieve satisfactory performance and outperforms the other traditional Chinese text classifiers.展开更多
【目的】GRAM(Glucosyltransferases,Rab-like GTPase activators and Myotubularins)是普遍存在于动、植物蛋白中的结构域,在植物生长发育及响应逆境胁迫等过程中发挥着重要功能。在马铃薯全基因组中鉴定GRAM基因家族成员,分析马铃薯G...【目的】GRAM(Glucosyltransferases,Rab-like GTPase activators and Myotubularins)是普遍存在于动、植物蛋白中的结构域,在植物生长发育及响应逆境胁迫等过程中发挥着重要功能。在马铃薯全基因组中鉴定GRAM基因家族成员,分析马铃薯GRAM家族基因在盐胁迫下的表达模式,探究GRAM家族在马铃薯盐胁迫过程中的作用。【方法】采用生物信息学方法鉴定马铃薯中GRAM家族成员,并对蛋白理化性质、染色体定位、亚细胞定位、基因结构、motif及共线性等方面进行分析。利用转录组测序和荧光定量PCR(RT-qPCR)对该家族成员在盐胁迫下的表达模式进行研究。【结果】在马铃薯中共鉴定到26个GRAM家族基因,不均匀地分布于7条染色体上;理化性质分析显示StGRAM全部为亲水性蛋白,大部分为碱性蛋白;亚细胞定位预测StGRAM蛋白大部分存在于叶绿体和细胞核;根据系统进化分析可将StGRAM家族分为3个亚族,同一亚族成员具有相似的基因结构及motif分布;通过马铃薯物种内共线性分析发现StGRAM仅有一对同源基因,物种间共线性显示StGRAM在水稻和拟南芥中分别存在5对和3对同源基因;在StGRAM基因启动子区发现大量的激素响应元件和逆境胁迫响应元件;转录组测序分析和RT-qPCR分析显示,StGRAM基因受盐胁迫的诱导表达,可能参与了马铃薯对盐胁迫的响应过程,StGRAM25基因可能对中性盐和碱性盐有不同的响应模式。【结论】StGRAM基因家族在马铃薯盐胁迫响应和信号转导过程中发挥着重要作用。展开更多
A space-based bistatic radar system composed of two space-based radars as the transmitter and the receiver respectively has a wider surveillance region and a better early warning capability for high-speed targets,and ...A space-based bistatic radar system composed of two space-based radars as the transmitter and the receiver respectively has a wider surveillance region and a better early warning capability for high-speed targets,and it can detect focused space targets more flexibly than the monostatic radar system or the ground-based radar system.However,the target echo signal is more difficult to process due to the high-speed motion of both space-based radars and space targets.To be specific,it will encounter the problems of Range Cell Migration(RCM)and Doppler Frequency Migration(DFM),which degrade the long-time coherent integration performance for target detection and localization inevitably.To solve this problem,a novel target detection method based on an improved Gram Schmidt(GS)-orthogonalization Orthogonal Matching Pursuit(OMP)algorithm is proposed in this paper.First,the echo model for bistatic space-based radar is constructed and the conditions for RCM and DFM are analyzed.Then,the proposed GS-orthogonalization OMP method is applied to estimate the equivalent motion parameters of space targets.Thereafter,the RCM and DFM are corrected by the compensation function correlated with the estimated motion parameters.Finally,coherent integration can be achieved by performing the Fast Fourier Transform(FFT)operation along the slow time direction on compensated echo signal.Numerical simulations and real raw data results validate that the proposed GS-orthogonalization OMP algorithm achieves better motion parameter estimation performance and higher detection probability for space targets detection.展开更多
BACKGROUND Pylephlebitis is an extremely rare form of septic thrombophlebitis involving the portal vein,carrying high rates of morbidity and mortality.CASE SUMMARY We present a case of a 42-year-old male with no past ...BACKGROUND Pylephlebitis is an extremely rare form of septic thrombophlebitis involving the portal vein,carrying high rates of morbidity and mortality.CASE SUMMARY We present a case of a 42-year-old male with no past medical history who presented with acute onset of abdominal pain and altered mental status with laboratory tests demonstrating new-onset acute liver failure.Pylephlebitis was determined to be the underlying etiology due to subsequent workup revealing polymicrobial gram-negative anaerobic bacteremia and complete thrombosis of the main and left portal veins.To our knowledge,this is the first documented case of acute liver failure as a potential life-threatening complication of pylephlebitis.CONCLUSION Our case highlights the importance of considering pylephlebitis in the broad differential for abdominal pain,especially if there are co-existing risk factors for hypercoagulability.We also demonstrate that fulminant hepatic failure in these patients can potentially be reversible with the immediate initiation of antibiotics and anticoagulation.展开更多
基金Supported by the China Postdoctoral Science Foundation
文摘We explore the techniques of utilizing N gram information to categorize Chinese text documents hierarchically so that the classifier can shake off the burden of large dictionaries and complex segmentation processing, and subsequently be domain and time independent. A hierarchical Chinese text classifier is implemented. Experimental results show that hierarchically classifying Chinese text documents based N grams can achieve satisfactory performance and outperforms the other traditional Chinese text classifiers.
文摘【目的】GRAM(Glucosyltransferases,Rab-like GTPase activators and Myotubularins)是普遍存在于动、植物蛋白中的结构域,在植物生长发育及响应逆境胁迫等过程中发挥着重要功能。在马铃薯全基因组中鉴定GRAM基因家族成员,分析马铃薯GRAM家族基因在盐胁迫下的表达模式,探究GRAM家族在马铃薯盐胁迫过程中的作用。【方法】采用生物信息学方法鉴定马铃薯中GRAM家族成员,并对蛋白理化性质、染色体定位、亚细胞定位、基因结构、motif及共线性等方面进行分析。利用转录组测序和荧光定量PCR(RT-qPCR)对该家族成员在盐胁迫下的表达模式进行研究。【结果】在马铃薯中共鉴定到26个GRAM家族基因,不均匀地分布于7条染色体上;理化性质分析显示StGRAM全部为亲水性蛋白,大部分为碱性蛋白;亚细胞定位预测StGRAM蛋白大部分存在于叶绿体和细胞核;根据系统进化分析可将StGRAM家族分为3个亚族,同一亚族成员具有相似的基因结构及motif分布;通过马铃薯物种内共线性分析发现StGRAM仅有一对同源基因,物种间共线性显示StGRAM在水稻和拟南芥中分别存在5对和3对同源基因;在StGRAM基因启动子区发现大量的激素响应元件和逆境胁迫响应元件;转录组测序分析和RT-qPCR分析显示,StGRAM基因受盐胁迫的诱导表达,可能参与了马铃薯对盐胁迫的响应过程,StGRAM25基因可能对中性盐和碱性盐有不同的响应模式。【结论】StGRAM基因家族在马铃薯盐胁迫响应和信号转导过程中发挥着重要作用。
文摘A space-based bistatic radar system composed of two space-based radars as the transmitter and the receiver respectively has a wider surveillance region and a better early warning capability for high-speed targets,and it can detect focused space targets more flexibly than the monostatic radar system or the ground-based radar system.However,the target echo signal is more difficult to process due to the high-speed motion of both space-based radars and space targets.To be specific,it will encounter the problems of Range Cell Migration(RCM)and Doppler Frequency Migration(DFM),which degrade the long-time coherent integration performance for target detection and localization inevitably.To solve this problem,a novel target detection method based on an improved Gram Schmidt(GS)-orthogonalization Orthogonal Matching Pursuit(OMP)algorithm is proposed in this paper.First,the echo model for bistatic space-based radar is constructed and the conditions for RCM and DFM are analyzed.Then,the proposed GS-orthogonalization OMP method is applied to estimate the equivalent motion parameters of space targets.Thereafter,the RCM and DFM are corrected by the compensation function correlated with the estimated motion parameters.Finally,coherent integration can be achieved by performing the Fast Fourier Transform(FFT)operation along the slow time direction on compensated echo signal.Numerical simulations and real raw data results validate that the proposed GS-orthogonalization OMP algorithm achieves better motion parameter estimation performance and higher detection probability for space targets detection.
文摘BACKGROUND Pylephlebitis is an extremely rare form of septic thrombophlebitis involving the portal vein,carrying high rates of morbidity and mortality.CASE SUMMARY We present a case of a 42-year-old male with no past medical history who presented with acute onset of abdominal pain and altered mental status with laboratory tests demonstrating new-onset acute liver failure.Pylephlebitis was determined to be the underlying etiology due to subsequent workup revealing polymicrobial gram-negative anaerobic bacteremia and complete thrombosis of the main and left portal veins.To our knowledge,this is the first documented case of acute liver failure as a potential life-threatening complication of pylephlebitis.CONCLUSION Our case highlights the importance of considering pylephlebitis in the broad differential for abdominal pain,especially if there are co-existing risk factors for hypercoagulability.We also demonstrate that fulminant hepatic failure in these patients can potentially be reversible with the immediate initiation of antibiotics and anticoagulation.
