Cross correlation

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  • 文章类型: Journal Article
    在这篇短文中,我们概述了电子环形多极的概念,以及它们在非磁性和磁性材料中具有相关物理性质的顺序。鉴于对称性和与狄拉克理论的联系,引入了环形多极子作为微观电子变量。它们是根据晶体学和磁性点组进行fi分类的,这使我们能够以透明和统一的方式讨论各种可能的交叉相关性。环形阶和相关现象的代表性例子,并给出了这些命令之间的相互关系,专注于单极子和偶极子。环形多极的概念将促进未来对未知电子相位及其相关物理现象的观测和识别的研究。 .
    In this short article, we overview a concept of electronic toroidal multipoles, and their ordering with associated physical properties in non-magnetic and magnetic materials. The toroidal multipoles are introduced as microscopic electronic variables in view of symmetry and connection to Dirac theory. They are classified according to crystallographic and magnetic point groups, which allows us to discuss various possible cross correlations in a transparent and unified manner. The representative examples of toroidal orders and related phenomena, and the mutual relationship between these orders are given, with focusing on monopoles and dipoles. The concept of toroidal multipoles would promote future studies toward observations and identifications of unknown electronic phases and their related physical phenomena. .
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  • 文章类型: Journal Article
    这项研究调查了通过测量动脉脉搏波的强度和时间来识别射血分数降低(HFrEF)的心力衰竭的敏感性和特异性。先前验证的方法结合超快B型超声,平面波传输,使用奇异值分解和斑点跟踪来表征收缩早期和晚期发生的压缩和解压缩(“S”和“D”)波,分别,在左心室射血分数(LVEF)<40%的门诊患者的颈动脉中,通过超声心动图确定,心力衰竭的体征和症状,或LVEF≥50%且没有心力衰竭的体征或症状。平均而言,HFrEF组的S波强度和能量显著降低,心电图的R波和S波之间的间隔更大,S波和D波之间的间隔减小,S波偏移的增加,一种新的度量,它表征了S波远离ECG的R波并朝向D波的定时偏移(所有p<0.01)。接收器操作特征(ROC)首次用于量化波浪指标对个体参与者的分类。S波强度和能量使ROC下的面积为0.76-0.83,ECG-S波间隔为0.85-0.88,S波偏移为0.88-0.92。因此,这些方法,使用简单,不需要复杂的解释,提供HFrEF的敏感和特异性鉴定。如果在初级保健中获得了类似的结果,它们可以构成心力衰竭筛查技术的基础。
    This study investigated the sensitivity and specificity of identifying heart failure with reduced ejection fraction (HFrEF) from measurements of the intensity and timing of arterial pulse waves. Previously validated methods combining ultrafast B-mode ultrasound, plane-wave transmission, singular value decomposition (SVD), and speckle tracking were used to characterize the compression and decompression (\"S\" and \"D\") waves occurring in early and late systole, respectively, in the carotid arteries of outpatients with left ventricular ejection fraction (LVEF) < 40%, determined by echocardiography, and signs and symptoms of heart failure, or with LVEF ≥ 50% and no signs or symptoms of heart failure. On average, the HFrEF group had significantly reduced S-wave intensity and energy, a greater interval between the R wave of the ECG and the S wave, a reduced interval between the S and D waves, and an increase in the S-wave shift (SWS), a novel metric that characterizes the shift in timing of the S wave away from the R wave of the ECG and toward the D wave (all P < 0.01). Receiver operating characteristics (ROCs) were used to quantify for the first time how well wave metrics classified individual participants. S-wave intensity and energy gave areas under the ROC of 0.76-0.83, the ECG-S-wave interval gave 0.85-0.88, and the S-wave shift gave 0.88-0.92. Hence the methods, which are simple to use and do not require complex interpretation, provide sensitive and specific identification of HFrEF. If similar results were obtained in primary care, they could form the basis of techniques for heart failure screening.NEW & NOTEWORTHY We show that heart failure with reduced ejection fraction can be detected with excellent sensitivity and specificity in individual patients by using B-mode ultrasound to detect altered pulse wave intensity and timing in the carotid artery.
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  • 文章类型: Journal Article
    我们介绍McDAPS,一种交互式软件,用于从无创多通道生理记录中评估自主神经失衡。McDAPS提供了用于数据可视化的图形用户界面,节拍处理和交互式分析。该软件提取逐搏RR间期收缩压,舒张压,光电血管容积图的脉冲幅度和脉冲-脉冲间隔。分析模块包括固定和时变功率谱分析,移动相关分析和单变量分析。如果必须以相同的方式处理多个数据集,则也可以以批处理模式执行分析。程序以标准CSV格式导出结果。McDAPS在MATLAB中运行,并且在MSWindows和MAC操作系统上支持。MATLAB源代码可在https://github.com/thuptimd/McDAPS获得。git.
    We introduce McDAPS, an interactive software for assessing autonomic imbalance from non-invasive multi-channel physiological recordings. McDAPS provides a graphical user interface for data visualization, beat-to-beat processing and interactive analyses. The software extracts beat-to-beat RR interval systolic blood pressure, diastolic blood pressure, the pulse amplitude of photoplethysmogram and the pulse-to-pulse interval. The analysis modules include stationary and time-varying power spectral analyses, moving-correlation analysis and univariate analyses. Analyses can also be performed in batch mode if multiple datasets have to be processed in the same way. The program exports results in standard CSV format. McDAPS runs in MATLAB, and is supported on MS Windows and MAC OS systems. The MATLAB source code is available at https://github.com/thuptimd/McDAPS.git.
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  • 文章类型: Journal Article
    内在无序蛋白(IDPs)在脯氨酸残基中显著富集,可以填充称为PPII螺旋的特定局部次级结构元素,特点是小的包装密度。脯氨酸通常被认为会促进疾病,但它可以参与特定的π·CH与芳香族侧链的相互作用,导致多肽的构象灵活性降低。微分局部运动动力学与预制结构元素的稳定有关,并且可以用作建立远程相互作用的成核位点。因此,非常需要进行NMR实验来探测脯氨酸环系统的动力学。在这里,我们提出了一种基于13C检测的脉冲方案,以量化脯氨酸残基中亚甲基CH2基团的偶极-偶极交叉相关弛豫(CCR)速率。应用13C-CON检测策略提供了精致的光谱分辨率,即使在接近生理条件的情况下,也可以应用于高分子量IDPs。脉冲方案说明了应用于220个氨基酸长的蛋白质骨桥蛋白,一种参与炎症和癌症进展的细胞外细胞因子,和一个构建体,其中三个脯氨酸-芳香族序列片段已经突变。
    Intrinsically disordered proteins (IDPs) are significantly enriched in proline residues, which can populate specific local secondary structural elements called PPII helices, characterized by small packing densities. Proline is often thought to promote disorder, but it can participate in specific π·CH interactions with aromatic side chains resulting in reduced conformational flexibilities of the polypeptide. Differential local motional dynamics are relevant for the stabilization of preformed structural elements and can serve as nucleation sites for the establishment of long-range interactions. NMR experiments to probe the dynamics of proline ring systems would thus be highly desirable. Here we present a pulse scheme based on 13C detection to quantify dipole-dipole cross-correlated relaxation (CCR) rates at methylene CH2 groups in proline residues. Applying 13C-CON detection strategy provides exquisite spectral resolution allowing applications also to high molecular weight IDPs even in conditions approaching the physiological ones. The pulse scheme is illustrated with an application to the 220 amino acids long protein Osteopontin, an extracellular cytokine involved in inflammation and cancer progression, and a construct in which three proline-aromatic sequence patches have been mutated.
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  • 文章类型: Journal Article
    股票市场通常被视为经济的晴雨表,甚至在经济活动之前就对国际货币政策作出反应。许多中央银行已转向非常规政策措施,以应对各种金融危机,例如2007-2009年的全球金融危机或最近由COVID-19引起的危机。为了研究整体国际货币政策与股票市场的相互关系,我们采用每日影子空头利率(SSR),它的优点是允许在非常规和常规制度之间进行比较。分析是通过使用多重分形去趋势互相关分析(MF-DXA)的多重分形上下文进行的,考虑2000年1月1日至2022年3月31日的每日数据以及特定国家的SSR和八个发达经济体的股票市场。主要实证研究结果如下:(i)所有国家特定的SSR与股票市场对都具有显著的多重分形特征(ii)NZ-SSR/NZX50、US-SSR/DJIA、和CN-SSR/S&PTSX具有最高的多重分形模式,而EU-SSR/欧元区指数具有最低的多重分形模式(iii)澳大利亚和新西兰股票市场与SSR表现出反持续性的交叉相关性,而其余的在其多重分形方面具有持续的交叉相关性。最后,这项研究的结果对中央银行和股票市场参与者有几个重要的启示。
    Stock markets are generally perceived as a barometer of the economy and respond to international monetary policies even before economic activities. Many central banks have turned to unconventional policy measures in response to various financial crises such as the global financial crisis of 2007-2009 or the recent crisis caused by COVID-19. To examine the cross-correlation of overall international monetary policies with stock markets, we employ the daily shadow short rate (SSR), which has the advantage of allowing comparison across unconventional and conventional regimes. The analysis is made through a multifractal context using multifractal detrended cross correlation analysis (MF-DXA), considering daily data from 1st January 2000 to 31st March 2022 and country specific SSR and the stock markets of eight developed economies. The main empirical findings are the following: (i) all the country specific pairs of SSR with stock markets have significant multifractal characteristics (ii) the pairs of NZ-SSR/NZX50, US-SSR/DJIA, and CN-SSR/S&P TSX have the highest multifractal patterns while EU-SSR/Euro-area Index has the lowest multifractal patterns (iii) Australian and New Zealand stock markets exhibit anti-persistent cross-correlation with SSR while the remainder have persistent cross-correlation in their multifractality. Lastly, the findings of this study have several important implications for central banks and stock market participants.
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  • 文章类型: Journal Article
    已显示膜联蛋白A1(A1)与S100A11形成四聚体复合物(A1t),其涉及钙稳态和EGFR途径。在这项工作中,首次生成了A1t的全长模型。对完整的A1t模型进行了数百纳秒的多次分子动力学模拟,以评估A1t的结构和动力学。这些模拟产生了A1N末端(ND)的三种结构,其通过主成分分析鉴定。所有三个结构的前11个A1-ND残基的方向和相互作用都是保守的,它们的结合模式与膜联蛋白A2-p11四聚体中的膜联蛋白A2N末端的结合模式惊人地相似。在这项研究中,我们提供了A1t的详细原子信息。在A1-ND和两个S100A11单体之间的A1t内鉴定出强相互作用。A1的残基M3,V4,S5,E6,L8,K9,W12,E15和E18是A1与S100A11二聚体之间最强的相互作用。A1t的不同构象归因于A1-ND的W12与S100A11的M63之间的相互作用,这引起了A1-ND的扭结。互相关分析显示整个A1t的运动具有很强的相关性。无论构象如何,在所有模拟中在ND和S100A11之间观察到强的正相关。这项工作表明,A1-ND的前11个残基与S100A11的稳定结合可能是膜联蛋白-S100复合物的主题,并且A1-ND的灵活性允许A1t的多种构象。由RamaswamyH.Sarma沟通。
    Annexin A1 (A1) has been shown to form a tetrameric complex (A1t) with S100A11 which is implicated in calcium homeostasis and EGFR pathways. In this work, a full-length model of the A1t was generated for the first time. Multiple molecular dynamics simulations were performed on the complete A1t model for several hundred nanoseconds each to assess the structure and dynamics of A1t. These simulations yielded three structures for the A1 N-terminus (ND) which were identified via principal component analysis. The orientations and interactions of the first 11 A1-ND residues for all three structures were conserved, and their binding modes were strikingly similar to those of the Annexin A2 N-terminus in the Annexin A2-p11 tetramer. In this study, we provided detailed atomistic information for the A1t. Strong interactions were identified within the A1t between the A1-ND and both S100A11 monomers. Residues M3, V4, S5, E6, L8, K9, W12, E15, and E18 of A1 were the strongest interactions between A1 and the S100A11 dimer. The different conformations of the A1t were attributed to the interaction between W12 of the A1-ND with M63 of S100A11 which caused a kink in the A1-ND. Cross-correlation analysis revealed strong correlated motion throughout the A1t. Strong positive correlation was observed between the ND and S100A11 in all simulations regardless of conformation. This work suggests that the stable binding of the first 11 residues of A1-ND to S100A11 is potentially a theme for Annexin-S100 complexes and that the flexibility of the A1-ND allows for multiple conformations of the A1t.Communicated by Ramaswamy H. Sarma.
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  • 文章类型: Journal Article
    功能近红外光谱是一种光学脑监测技术,使用NIRS进行功能神经成像。它使用近红外光来测量大脑活动并估计由于运动活动而引起的大脑中的皮质血液动力学活动。功能性NIRS通过光学吸收测量氧合和脱氧血红蛋白中氧水平的变化。fNIRS信号分析中的主要挑战之一是由于来自多个源的噪声和伪影的干扰而导致的信号劣化。
    在这种情况下,本研究旨在利用图论分析大脑不同区域之间的连通性,从而分析大脑网络在功能参数方面的几何关联。在这项研究中,两个噪声去除过程(CBSI和TDDR)的影响,以及两种类型的相关fNIRS,如皮尔逊相关(PC),和互相关(CC)和各种全脑网络体系结构对单个参与者的图形测量的可重复性进行了仔细检查,以了解5%至50%的不同密度。使用测试-重测变异性(TRT)研究了图形在个体水平上的可重复性。
    在低密度下,二元网络中全局测量的重测可变性很大,不管噪声去除方法或相关性的种类。对于加权网络观察到非常低的测试重置值,并且对于整个图的测量结果具有很好的再现性。比较各种方法的重测值时,这种相关性,相关性的绝对值,权重计算方法对原始相关值均有显著的重大影响。
    基于以绝对互相关为权重的加权网络,这项研究表明,归一化的全局图测量是可靠的。用于去除噪声的节点定义技术对于可再现的归一化图度量不是必需的。
    UNASSIGNED: Functional Near-Infrared Spectroscopy is an optical brain monitoring technique which uses NIRS to perform functional neuroimaging. It uses near-infrared light for measuring brain activity and to estimate the cortical hemodynamic activity in the brain due to motor activity. Functional NIRS measures the changes in oxygen levels in oxygenated and deoxygenated hemoglobin by optical absorption. One of the main challenges in the analysis of fNIRS signals is the signal degradation due to the interference from noise and artifacts from multiple sources.
    UNASSIGNED: In this context, this research aims to analyze the connectivity between different regions of the brain using graph theory and hence the geometrical association of brain networks in terms of functional parameters. In this study, the impact of two noise removal processes (CBSI and TDDR), along with two types of correlation fNIRS such as Pearson\'s Correlation (PC), and Cross Correlation (CC) and various whole-brain network architectures on the reproducibility of graph measurements for individual participants has been carefully examined for different densities ranging from 5% to 50%.The graph measures\' repeatability at the individual level was studied using the test-retest variability (TRT).
    UNASSIGNED: The test-retest variability for global measurements in binary networks was substantially large at low densities, regardless of the noise removal method or the kind of correlation. Very low test -reset values are observed for weighted networks and great reproducibility for measures of the entire graph. When comparing the test-retest values for various methods, the kind of correlation, the absolute value of the correlation, and the weight calculation method on the raw correlation value all had significant major effects.
    UNASSIGNED: Based on a weighted network with the absolute cross correlation functioning as the weight, this study revealed that normalized global graph measurements were reliable. The node definition techniques that were utilized to remove noise were not essential for the normalized graph measures to be reproducible.
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  • 文章类型: Journal Article
    荧光相关光谱(FCS)是一种广泛使用的测量分子扩散和化学动力学的方法。然而,当考虑到荧光物质的混合物时,传统的FCS方法在提取不同物种的自相关和不同物种之间的交叉相关方面存在局限性。最近开发的基于时间标记时间分辨(TTTR)光子记录的荧光寿命相关光谱(FLCS),它可以记录每个光子的全局和微到达时间,已用于根据荧光寿命区分不同的物种。这里,基于由TTTR光子流构建的二维寿命衰减图,我们开发了一种定量的寿命反卷积FCS模型(LDFCS),以提取精确的化学速率,用于多物种系统中的化学转化。LDFCS模型的关键点是根据荧光寿命的全局分布分离不同的物种,然后从每个延迟时间的光子对的微到达时间构建的二维寿命衰减图中对自相关和互相关进行反卷积。
    Fluorescence correlation spectroscopy (FCS) is a widely used method for measuring molecular diffusion and chemical kinetics. However, when a mixture of fluorescent species is taken into account, the conventional FCS method has limitations in extracting autocorrelations for different species and cross correlations between different species. Recently developed fluorescence lifetime correlation spectroscopy (FLCS) based on time-tagged time-resolved (TTTR) photon recording, which can record the global and micro arrival time for each individual photon, has been used to discriminate different species according to fluorescence lifetime. Here, based on two-dimensional lifetime decay maps constructed from TTTR photon stream, we have developed a quantitative lifetime-deconvolution FCS model (LDFCS) to extract precise chemical rates for chemical conversions in multi-species systems. The key point of LDFCS model is separation of different species according to the global distribution of fluorescence lifetime and then deconvolution of autocorrelations and cross-correlations from the two-dimensional lifetime decay maps constructed by the micro arrival times of photon pairs at each delay time.
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  • 文章类型: Journal Article
    高密度神经生理学工具的最新发展现在可以记录本地数百个单个神经元,高度互联的神经网络。这种录音的许多优点之一是它们大大增加了可识别的数量,神经元之间的功能性相互作用,从而提供了前所未有的局部电路视图。使用高密度,非人类灵长类动物初级视觉皮层单个新皮层列的神经像素记录,我们使用已建立的互相关方法鉴定了1000个功能相互作用的神经元对。我们的结果揭示了单个皮质柱内功能相互作用的同步性和强度的清晰而系统的变化。尽管神经元位于同一列,两种相互作用的度量在很大程度上取决于神经元对之间的垂直距离,以及刺激调整的相似性。此外,我们利用大量功能相互作用对提供的统计能力,根据神经元的互相关函数对神经元之间的相互作用进行分类。这些分析确定了不同的,整个人群中功能相互作用的假定类别。这些类型的功能性相互作用通过其在定义的层状区室中的独特分布得到证实,并且与V1皮质回路的已知特性一致。例如简单细胞和复杂细胞之间的超前-滞后关系。我们的结果为使用高密度神经生理学记录来评估局部神经元网络中的电路级相互作用提供了清晰的原理证明。
    Recent developments in high-density neurophysiological tools now make it possible to record from hundreds of single neurons within local, highly interconnected neural networks. Among the many advantages of such recordings is that they dramatically increase the quantity of identifiable, functional interactions between neurons thereby providing an unprecedented view of local circuits. Using high-density, Neuropixels recordings from single neocortical columns of primary visual cortex in nonhuman primates, we identified 1000s of functionally interacting neuronal pairs using established crosscorrelation approaches. Our results reveal clear and systematic variations in the synchrony and strength of functional interactions within single cortical columns. Despite neurons residing within the same column, both measures of interactions depended heavily on the vertical distance separating neuronal pairs, as well as on the similarity of stimulus tuning. In addition, we leveraged the statistical power afforded by the large numbers of functionally interacting pairs to categorize interactions between neurons based on their crosscorrelation functions. These analyses identified distinct, putative classes of functional interactions within the full population. These classes of functional interactions were corroborated by their unique distributions across defined laminar compartments and were consistent with known properties of V1 cortical circuitry, such as the lead-lag relationship between simple and complex cells. Our results provide a clear proof-of-principle for the use of high-density neurophysiological recordings to assess circuit-level interactions within local neuronal networks.
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  • 文章类型: Journal Article
    成人初级视觉皮层特征表现出良好的取向选择性。然而,施加非首选刺激几分钟(适应)或应用抗抑郁药,比如氯胺酮,移动调谐曲线的峰值,给神经元赋予一种新的选择性。氯胺酮对V1神经回路的影响尚未确定。本调查探索(在控制下,适应后,并在局部应用氯胺酮后),方向选择性的改变及其对小鼠和猫神经元之间功能关系的影响。揭示了两个主要结果。单眼刺激的电生理神经元反应表明,在适应后表现出大的方向变化的细胞中,氯胺酮促进细胞的恢复。而在适应后显示小变化的单位中,药物增加了方向变化的幅度。此外,成对交叉相关图分析表明,神经元之间的功能关系发生了变化,揭示了氯胺酮应用后更新的微电路。我们报告在猫,但不是在老鼠,氯胺酮显著提高了连接率,他们的长处,和神经元同步性的增强。
    Adult primary visual cortex features well demonstrated orientation selectivities. However, the imposition of a non-preferred stimulus for many minutes (adaptation) or the application of an antidepressant drug, such as ketamine, shifts the peak of the tuning curve, assigning a novel selectivity to a neuron. The effect of ketamine on V1 neural circuitry is not yet ascertained. The present investigation explores (in control, post-adaptation, and following local ketamine application) the modification of orientation selectivities and its outcome on functional relationships between neurons in mouse and cat. Two main results are revealed. Electrophysiological neuronal responses of monocular stimulation show that in cells exhibiting large orientation shifts after adaptation, ketamine facilitates the cell\'s recovery. Whereas in units displaying small shifts following adaptation, the drug increases the magnitude of orientation shifts. In addition, pair-wise cross correlogram analyses show modifications of functional relationships between neurons revealing updated micro-circuits as a consequence of ketamine application. We report in cat but not in mouse, that ketamine significantly increases the connectivity rate, their strengths, and an enhancement of neuronal synchrony.
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