小血管疾病在脑血管疾病中占有重要地位,是导致老年人认知能力下降和功能丧失的主要原因。脑小血管病(cerebral small vessel disease,CSVD)是以小血管结构或功能病变所导致的一系列临床、病理和影像学改变为主要表现的综合征,患者常以...小血管疾病在脑血管疾病中占有重要地位,是导致老年人认知能力下降和功能丧失的主要原因。脑小血管病(cerebral small vessel disease,CSVD)是以小血管结构或功能病变所导致的一系列临床、病理和影像学改变为主要表现的综合征,患者常以头晕为主要症状和主诉。近年来,越来越多的研究表明CSVD可导致头晕,但其机制还尚未完全明确。本文就头晕与CSVD的关系及其可能的机制进行综述,旨在为头晕患者发生CSVD的识别和诊治提供一定的参考。展开更多
The resistance of dominant rice varieties in Guangzhou against rice blast(Magnaporthe oryzae)and bacterial blight(Xanthomonas oryzae pv.oryzae)were evaluated by artificial inoculation and field natural blast nursery i...The resistance of dominant rice varieties in Guangzhou against rice blast(Magnaporthe oryzae)and bacterial blight(Xanthomonas oryzae pv.oryzae)were evaluated by artificial inoculation and field natural blast nursery identification.Among 11 varieties tested,seven varieties showed resistance to rice blast,accounting for 63.6%;two varieties were highly resistant,accounting for 18.2%;three varieties were resistant,accounting for 27.3%;two varieties were moderately resistant,accounting for 18.2%;four varieties were susceptible(moderately susceptible),accounting for 36.4%.Varieties showed different resistance against the prevailing pathotype IV of bacterial blight;one variety was resistant,accounting for 9.1%;three varieties were moderately resistant,accounting for 27.3%;five varieties were moderately susceptible,accounting for 45.5%;one variety was susceptible,accounting for 9.1%;one variety was highly susceptible,accounting for 9.1%;all varieties tested showed susceptible to the virulent pathotype V.Huanghuazhan,Yuejingsimiao 2 and Fengxiuzhan showed resistance against both bacterial blight(pathotype IV)and rice blast,accounting for 27.3%.It is helpful to reduce the production risk by extending such dominant rice varieties with good resistance to rice blast and bacterial blight.展开更多
文摘小血管疾病在脑血管疾病中占有重要地位,是导致老年人认知能力下降和功能丧失的主要原因。脑小血管病(cerebral small vessel disease,CSVD)是以小血管结构或功能病变所导致的一系列临床、病理和影像学改变为主要表现的综合征,患者常以头晕为主要症状和主诉。近年来,越来越多的研究表明CSVD可导致头晕,但其机制还尚未完全明确。本文就头晕与CSVD的关系及其可能的机制进行综述,旨在为头晕患者发生CSVD的识别和诊治提供一定的参考。
文摘智能车辆视觉目标具有非线性、噪声分布非高斯性的典型特点,现有算法难以实时估计目标的状态。针对识别物体复杂且多变,很难用完全的特征来描述待识别目标及其背景的不断变化,提出了一种用于融合颜色特征及SURF(Speed-Up Robust Features)特征的协方差矩阵来改进粒子滤波算法,从而提升视觉目标跟踪的实时性,满足智能车辆的要求。首先,对采集的图像进行预处理来获取感兴趣区域。接着,通过融合颜色特征及SURF特征构造范围感兴趣区域(Region Of Interest,ROI)的目标特征协方差矩阵,建立目标状态预测模型及状态观测模型,用于改进粒子滤波算法粒子重采样过程,实现对目标的精确跟踪。最后,将该方法与Mean-shift算法和颜色属性(CN)算法进行对比。实验结果表明,在智能车视觉跟踪过程中对光环境瞬时变化、目标物体存在短时遮挡以及目标物体姿态改变时,该算法在满足智能车辆对实时性要求的前提下,有效提升算法的精确度及鲁棒性。
基金Supported by National Key R&D Program of China(2017YFD0100100)Guangdong Science and Technology Project(2019B020217003,2018B030311035,2020A1515011213).
文摘The resistance of dominant rice varieties in Guangzhou against rice blast(Magnaporthe oryzae)and bacterial blight(Xanthomonas oryzae pv.oryzae)were evaluated by artificial inoculation and field natural blast nursery identification.Among 11 varieties tested,seven varieties showed resistance to rice blast,accounting for 63.6%;two varieties were highly resistant,accounting for 18.2%;three varieties were resistant,accounting for 27.3%;two varieties were moderately resistant,accounting for 18.2%;four varieties were susceptible(moderately susceptible),accounting for 36.4%.Varieties showed different resistance against the prevailing pathotype IV of bacterial blight;one variety was resistant,accounting for 9.1%;three varieties were moderately resistant,accounting for 27.3%;five varieties were moderately susceptible,accounting for 45.5%;one variety was susceptible,accounting for 9.1%;one variety was highly susceptible,accounting for 9.1%;all varieties tested showed susceptible to the virulent pathotype V.Huanghuazhan,Yuejingsimiao 2 and Fengxiuzhan showed resistance against both bacterial blight(pathotype IV)and rice blast,accounting for 27.3%.It is helpful to reduce the production risk by extending such dominant rice varieties with good resistance to rice blast and bacterial blight.
