ICa

ICA
  • 文章类型: Journal Article
    分子是生命及其不同构象的基本组成部分(即,形状)至关重要地决定了它们在生物体中发挥的功能作用。低温电子显微镜(cryo-EM)允许获取单个分子的大图像数据集。计算低温EM的最新进展使学习构象景观的潜在变量模型成为可能。然而,解释这些潜在空间仍然是一个挑战,因为它们的个体维度通常是任意的。我们工作的关键信息是,可以将这种解释挑战视为独立成分分析(ICA)问题,在该问题中,我们寻求具有可识别性的模型。这意味着,他们有一个本质上独特的解决方案,代表构象潜在空间,该空间将分子在自然界中配备的不同自由度分开。因此,我们的目标是推进cryo-EM的计算领域超越可视化,因为我们将其与(非线性)ICA的理论框架联系起来,并讨论对可识别模型的需求,改进的指标,和基准。往前走,我们提出了增强cryo-EM潜在空间解纠缠的未来方向,完善评估指标,探索利用基于物理的生物分子系统解码器的技术。此外,我们讨论了时间分辨单粒子成像的未来技术发展如何实现非线性ICA模型的应用,该模型可以发现自然界分子的真实构象变化。对可解释的构象潜在空间的追求将使研究人员能够解开复杂的生物过程并促进有针对性的干预。这对更广泛的药物发现和结构生物学具有重要意义。更一般地说,潜在变量模型被广泛部署在许多科学学科中。因此,如果我们想从令人印象深刻的非线性神经网络模型转向数学基础方法,可以帮助我们学习有关自然的新知识,那么我们在这项工作中提出的论点在AI科学中具有更广泛的应用。
    Molecules are essential building blocks of life and their different conformations (i.e., shapes) crucially determine the functional role that they play in living organisms. Cryogenic Electron Microscopy (cryo-EM) allows for acquisition of large image datasets of individual molecules. Recent advances in computational cryo-EM have made it possible to learn latent variable models of conformation landscapes. However, interpreting these latent spaces remains a challenge as their individual dimensions are often arbitrary. The key message of our work is that this interpretation challenge can be viewed as an Independent Component Analysis (ICA) problem where we seek models that have the property of identifiability. That means, they have an essentially unique solution, representing a conformational latent space that separates the different degrees of freedom a molecule is equipped with in nature. Thus, we aim to advance the computational field of cryo-EM beyond visualizations as we connect it with the theoretical framework of (nonlinear) ICA and discuss the need for identifiable models, improved metrics, and benchmarks. Moving forward, we propose future directions for enhancing the disentanglement of latent spaces in cryo-EM, refining evaluation metrics and exploring techniques that leverage physics-based decoders of biomolecular systems. Moreover, we discuss how future technological developments in time-resolved single particle imaging may enable the application of nonlinear ICA models that can discover the true conformation changes of molecules in nature. The pursuit of interpretable conformational latent spaces will empower researchers to unravel complex biological processes and facilitate targeted interventions. This has significant implications for drug discovery and structural biology more broadly. More generally, latent variable models are deployed widely across many scientific disciplines. Thus, the argument we present in this work has much broader applications in AI for science if we want to move from impressive nonlinear neural network models to mathematically grounded methods that can help us learn something new about nature.
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  • 文章类型: Journal Article
    基于热应激暴露后的急性小鼠模型,研究被动热疗如何影响静息状态的功能性脑活动。
    收集体重约24~29g、年龄12~16周龄的C57BL/6J雄性小鼠28只rs-fMRI数据。热疗组的小鼠(HT,40°C±0.5°C,40分钟)在麻醉准备扫描之前进行被动热疗。正常对照组(NC)处于常温状态(NC,20°C±2°C,40分钟)。数据预处理后,我们对HT(n=13)和NC(n=15)的数据进行了独立成分分析(ICA)和感兴趣区域(ROI)-ROI功能连接(FC)分析.
    组ICA分析表明,HT和NC均包含11个固有连接网络(ICN),可以分为四种类型的网络:皮层网络(CN),皮层下网络(SN),默认模式网络(DMN),和小脑网络。CN和SN属于感觉运动网络。与NC相比,HT中ICNs的功能网络组织发生改变,总体功能强度降低.此外,在CN中选择了13个ROI,SN,和DMN用于进一步的ROI-ROIFC分析。ROI-ROIFC分析显示被动热疗显著降低了以CN为代表的全脑的FC强度,SN,小鼠的DMN。
    长时间暴露于高温对小鼠的整体感知和认知水平的影响更大,这可能有助于理解神经元活动与生理热感觉和调节以及行为变化之间的关系。
    UNASSIGNED: To investigate how passive hyperthermia affect the resting-state functional brain activity based on an acute mouse model after heat stress exposure.
    UNASSIGNED: Twenty-eight rs-fMRI data of C57BL/6J male mice which weighing about 24 ∼ 29 g and aged 12 ∼ 16 weeks were collected. The mice in the hyperthermia group (HT, 40 °C ± 0.5 °C, 40 min) were subjected to passive hyperthermia before the anesthesia preparation for scanning. While the normal control group (NC) was subjected to normothermia condition (NC, 20 °C ± 2 °C, 40 min). After data preprocessing, we performed independent component analysis (ICA) and region of interested (ROI)-ROI functional connectivity (FC) analyses on the data of both HT (n = 13) and NC (n = 15).
    UNASSIGNED: The group ICA analysis showed that the HT and the NC both included 11 intrinsic connectivity networks (ICNs), and can be divided into four types of networks: the cortical network (CN), the subcortical network (SN), the default mode network (DMN), and cerebellar networks. CN and SN belongs to sensorimotor network. Compared with NC, the functional network organization of ICNs in the HT was altered and the overall functional intensity was decreased. Furthermore, 13 ROIs were selected in CN, SN, and DMN for further ROI-ROI FC analysis. The ROI-ROI FC analysis showed that passive hyperthermia exposure significantly reduced the FC strength in the overall brain represented by CN, SN, DMN of mice.
    UNASSIGNED: Prolonged exposure to high temperature has a greater impact on the overall perception and cognitive level of mice, which might help understand the relationship between neuronal activities and physiological thermal sensation and regulation as well as behavioral changes.
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  • 文章类型: Journal Article
    目标:坎图综合征(CS),具有复杂心血管表型的多系统疾病,由ATP敏感性钾(KATP)通道的Kir6.1/SUR2亚基中的GoF变体引起,其特点是全身血管阻力低,以及曲折,扩张的血管,脉搏波速度降低。因此,CS血管功能障碍是多因素的,同时具有肌强直和超弹性成分。为了剖析这种复杂性是否在血管平滑肌细胞(VSMC)内由细胞自主产生,或者作为对病理生理环境的二次反应,我们评估了人类诱导多能干细胞来源的VSMC(hiPSC-VSMC)的电特性和基因表达,从对照和CS患者来源的HiPSC分化,以及在本机鼠标控制和CSVSMC中。
    结果:从野生型(WT)和Kir6.1[V65M](CS)小鼠分离的主动脉和肠系膜动脉VSMC的全细胞电压钳显示电压门控K(Kv)或Ca2电流没有明显差异。Kv和Ca2+电流在从对照分化的验证的hiPSC-VSMC和CS患者来源的hiPSC之间也没有差异。虽然对照hiPSC-VSMC中的吡那地尔敏感的KATP电流与WT小鼠VSMC中的一致,它们在CShiPSC-VSMC中相当大。在电流钳位条件下,CShiPSC-VSMC也是超极化的,与基础钾电导增加一致,并为CS的音调降低和血管阻力降低提供了解释。在分离的CS小鼠主动脉中观察到顺应性增加,并与弹性蛋白mRNA表达增加有关。这与CShiPSC-VSMC中弹性蛋白mRNA的高水平一致,表明CS血管病变的超弹性成分是血管KATPGoF的细胞自主结果。
    结论:结果表明,hiPSC-VSMC重申了与初级VSMC相同的主要离子电流的表达,验证使用这些细胞来研究血管疾病。源自CS患者细胞的hiPSC-VSMC的结果表明,CS血管病变的肌强直和超弹性成分都是由VSMC内KATP过度活动驱动的细胞自主现象。
    OBJECTIVE: Cantu Syndrome (CS), a multisystem disease with a complex cardiovascular phenotype, is caused by GoF variants in the Kir6.1/SUR2 subunits of ATP-sensitive potassium (KATP) channels, and is characterized by low systemic vascular resistance, as well as tortuous, dilated vessels, and decreased pulse-wave velocity. Thus, CS vascular dysfunction is multifactorial, with both hypomyotonic and hyperelastic components. To dissect whether such complexities arise cell-autonomously within vascular smooth muscle cells (VSMCs), or as secondary responses to the pathophysiological milieu, we assessed electrical properties and gene expression in human induced pluripotent stem cell-derived VSMCs (hiPSC-VSMCs), differentiated from control and CS patient-derived hiPSCs, and in native mouse control and CS VSMCs.
    RESULTS: Whole-cell voltage-clamp of isolated aortic and mesenteric arterial VSMCs isolated from wild type (WT) and Kir6.1[V65M] (CS) mice revealed no clear differences in voltage-gated K+ (Kv) or Ca2+ currents. Kv and Ca2+ currents were also not different between validated hiPSC-VSMCs differentiated from control and CS patient-derived hiPSCs. While pinacidil-sensitive KATP currents in control hiPSC-VSMCs were consistent with those in WT mouse VSMCs, they were considerably larger in CS hiPSC-VSMCs. Under current-clamp conditions, CS hiPSC-VSMCs were also hyperpolarized, consistent with increased basal K conductance, and providing an explanation for decreased tone and decreased vascular resistance in CS. Increased compliance was observed in isolated CS mouse aortae, and was associated with increased elastin mRNA expression. This was consistent with higher levels of elastin mRNA in CS hiPSC-VSMCs, suggesting that the hyperelastic component of CS vasculopathy is a cell-autonomous consequence of vascular KATP GoF.
    CONCLUSIONS: The results show that hiPSC-VSMCs reiterate expression of the same major ion currents as primary VSMCs, validating the use of these cells to study vascular disease. Results in hiPSC-VSMCs derived from CS patient cells suggest that both the hypomyotonic and hyperelastic components of CS vasculopathy are cell-autonomous phenomena driven by KATP overactivity within VSMCs.
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  • 文章类型: Journal Article
    背景:由于战争,创伤后应激障碍(PTSD)的发病率目前正在增加,恐怖主义,和大流行性疾病的情况。因此,PTSD的准确检测对患者的治疗至关重要,为此,本研究旨在对PTSD患者与健康对照者进行分类.
    方法:使用19名PTSD和24名健康对照男性受试者的静息状态功能MRI(rs-fMRI)扫描,使用组水平独立成分分析(ICA)和t检验来识别大多数受影响的大脑区域的激活模式。将受创伤后应激障碍影响的受试者与健康对照的六种机器学习技术进行分类,包括随机森林,天真的贝叶斯,支持向量机,决策树,K-最近邻,线性判别分析,和深度学习三维3D-CNN的数据进行了比较。
    结果:分析了最常见的11个创伤暴露区域和健康大脑的rs-fMRI扫描,以观察其激活水平。杏仁核和脑岛区域被确定为PTSD受试者大脑中感兴趣区域中最激活的区域。此外,机器学习技术已应用于从ICA提取的组件,但模型提供低分类精度。ICA分量也被馈送到3D-CNN模型中,用5倍交叉验证方法训练。3D-CNN模型表现出很高的准确性,如98.12%,98.25%,和98.00%的平均训练,验证,和测试数据集,分别。
    结论:研究结果表明,3D-CNN是一种超越其他六种技术的方法,它有助于准确识别PTSD患者。
    BACKGROUND: The incidence rate of Posttraumatic stress disorder (PTSD) is currently increasing due to wars, terrorism, and pandemic disease situations. Therefore, accurate detection of PTSD is crucial for the treatment of the patients, for this purpose, the present study aims to classify individuals with PTSD versus healthy control.
    METHODS: The resting-state functional MRI (rs-fMRI) scans of 19 PTSD and 24 healthy control male subjects have been used to identify the activation pattern in most affected brain regions using group-level independent component analysis (ICA) and t-test. To classify PTSD-affected subjects from healthy control six machine learning techniques including random forest, Naive Bayes, support vector machine, decision tree, K-nearest neighbor, linear discriminant analysis, and deep learning three-dimensional 3D-CNN have been performed on the data and compared.
    RESULTS: The rs-fMRI scans of the most commonly investigated 11 regions of trauma-exposed and healthy brains are analyzed to observe their level of activation. Amygdala and insula regions are determined as the most activated regions from the regions-of-interest in the brain of PTSD subjects. In addition, machine learning techniques have been applied to the components extracted from ICA but the models provided low classification accuracy. The ICA components are also fed into the 3D-CNN model, which is trained with a 5-fold cross-validation method. The 3D-CNN model demonstrated high accuracies, such as 98.12%, 98.25 %, and 98.00 % on average with training, validation, and testing datasets, respectively.
    CONCLUSIONS: The findings indicate that 3D-CNN is a surpassing method than the other six considered techniques and it helps to recognize PTSD patients accurately.
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  • 文章类型: Journal Article
    长期以来,人们一直认为沿海马长轴的结构差异是有意义的功能差异的基础。最近的发现表明,海马的数据驱动分割将海马分为10个簇的图,其中包括前内侧,前外侧,和后前外侧,中间,和后部组件。我们使用空间学习实验测试了任务和经验是否可以调节这种聚类,在该实验中,男性和女性参与者接受了训练,可以在类似Google街景的环境中虚拟导航一个新的社区。在培训初期和为期两周的培训期结束时,参与者在导航路线时进行了扫描。使用10簇地图作为理想模板,我们发现,最终很好地学习邻域的参与者的海马簇图与理想状态一致-即使在学习的第二天-而且他们的簇图在两周的训练期内没有偏离.然而,最终学习邻居的参与者开始时海马聚类图与理想模板不一致,尽管经过两周的培训,它们的簇映射可能会变得更加刻板。有趣的是,这种改进似乎是特定于路线的:经过一些早期改进,当一条新路线被导航时,参与者的海马图恢复到不那么刻板的组织。我们得出的结论是,海马聚集并不仅仅依赖于解剖结构,而是由解剖学的组合驱动,任务,而且重要的是,经验。尽管如此,而海马集群可以随着经验而改变,有效的导航依赖于功能性海马活动以刻板的方式聚集,突出沿海马前后轴和内侧外侧轴的最佳处理划分。意义声明海马是对记忆和导航重要的大脑区域。最近的研究表明,当人们休息时,海马体内的加工活动模式可以揭示海马体内的不同加工区域。我们通过在个体学习如何在新的虚拟现实环境中导航时检查海马体中的处理来扩展这项工作。我们的发现表明,不仅海马的活动模式可靠地将海马分为子组件,而且海马的干净功能分割与更强的导航性能有关。因此,虽然个人可以使用他们的海马体以不同的方式处理信息,可能有一个理想的模板来支持有效的空间学习。
    Structural differences along the hippocampal long axis are believed to underlie meaningful functional differences. Yet, recent data-driven parcellations of the hippocampus subdivide the hippocampus into a 10-cluster map with anterior-medial, anterior-lateral, and posteroanterior-lateral, middle, and posterior components. We tested whether task and experience could modulate this clustering using a spatial learning experiment where male and female participants were trained to virtually navigate a novel neighborhood in a Google Street View-like environment. Participants were scanned while navigating routes early in training and after a 2 week training period. Using the 10-cluster map as the ideal template, we found that participants who eventually learn the neighborhood well have hippocampal cluster maps consistent with the ideal-even on their second day of learning-and their cluster mappings do not deviate over the 2 week training period. However, participants who eventually learn the neighborhood poorly begin with hippocampal cluster maps inconsistent with the ideal template, though their cluster mappings may become more stereotypical after the 2 week training. Interestingly this improvement seems to be route specific: after some early improvement, when a new route is navigated, participants\' hippocampal maps revert back to less stereotypical organization. We conclude that hippocampal clustering is not dependent solely on anatomical structure and instead is driven by a combination of anatomy, task, and, importantly, experience. Nonetheless, while hippocampal clustering can change with experience, efficient navigation depends on functional hippocampal activity clustering in a stereotypical manner, highlighting optimal divisions of processing along the hippocampal anterior-posterior and medial-lateral axes.
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  • 文章类型: Journal Article
    背景:完整结肠系膜切除术(CME)和中央血管脱离是结直肠癌手术中非常重要的手术方法。术前和术中评估主要结直肠血管的解剖结构是必要的,以避免大量出血。尤其是在内窥镜手术中。据报道,罕见的异常病例中结肠动脉(MCA)和回结肠动脉(ICA)具有共同的干。
    方法:患者是一名73岁女性,在结肠镜检查中被诊断为升结肠癌。术前腹部对比增强计算机断层扫描证实,MCA和ICA具有共同的躯干。她接受了腹腔镜回盲肠切除术治疗升结肠癌,并进行了D3淋巴结清扫。术中进行吲哚菁绿荧光成像。确认血管分叉后,在MCA分叉的远端解剖ICA。该患者已作为门诊病人被随访,术后2年无复发迹象。
    结论:呈现一例具有独特血管分叉模式的升结肠癌。术前和术中评估结直肠主要血管对于预防围手术期及术后并发症非常重要。
    BACKGROUND: Complete mesocolic excision (CME) and central vascular detachment are very important procedures in surgery for colorectal cancer. Preoperative and intraoperative assessments of the anatomy of major colorectal vessels are necessary to avoid massive bleeding, especially in endoscopic surgery. A case with a rare anomaly in which the middle colic artery (MCA) and ileocolic artery (ICA) had a common trunk is reported.
    METHODS: The patient was a 73-year-old woman diagnosed with ascending colon cancer on colonoscopy. Preoperative abdominal contrast-enhanced computed tomography confirmed that the MCA and ICA had a common trunk. She underwent laparoscopic ileocecal resection for the ascending colon cancer with D3 lymph node dissection. Intraoperative indocyanine green fluorescence imaging was conducted. After confirming vessel bifurcation, the ICA was dissected at the distal end of the MCA bifurcation. The patient has been followed as an outpatient, with no signs of recurrence as of 2 years postoperatively.
    CONCLUSIONS: A case of an ascending colon cancer with a unique vascular bifurcation pattern was presented. Preoperative and intraoperative evaluations of the major colorectal vessels are very important for preventing perioperative and postoperative complications.
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  • 文章类型: Journal Article
    本文提出了一种先进的EEG伪影去除和运动图像分类方法,该方法结合了四类迭代滤波和滤波器组公共空间模式算法以及改进的深度神经网络(DNN)分类器。该研究旨在通过解决EEG伪影和复杂运动成像任务带来的挑战来提高BCI系统的准确性和可靠性。该方法首先引入FCIF,一种新颖的去除眼部伪影的技术,利用迭代滤波和滤波器组。FCIF的数学公式允许有效的伪影缓解,从而提高脑电数据的质量。串联,介绍了FC-FBCSP算法,扩展滤波器组公共空间模式方法来处理四类运动图像分类。改进的DNN分类器增强了FC-FBCSP特征的辨别能力,优化分类过程。本文展示了一个全面的实验装置,以BCI竞赛IV数据集2a和2b的利用为特色。详细的预处理步骤,包括过滤和特征提取,以数学上的严谨性呈现。结果证明了FCIF的显着伪影去除能力以及FC-FBCSP与ModifiedDNN分类器结合的分类能力。对比分析强调了所提出的方法相对于基线方法的优越性,该方法达到了98.575%的平均精度。
    This paper presents an advanced approach for EEG artifact removal and motor imagery classification using a combination of Four Class Iterative Filtering and Filter Bank Common Spatial Pattern Algorithm with a Modified Deep Neural Network (DNN) classifier. The research aims to enhance the accuracy and reliability of BCI systems by addressing the challenges posed by EEG artifacts and complex motor imagery tasks. The methodology begins by introducing FCIF, a novel technique for ocular artifact removal, utilizing iterative filtering and filter banks. FCIF\'s mathematical formulation allows for effective artifact mitigation, thereby improving the quality of EEG data. In tandem, the FC-FBCSP algorithm is introduced, extending the Filter Bank Common Spatial Pattern approach to handle four-class motor imagery classification. The Modified DNN classifier enhances the discriminatory power of the FC-FBCSP features, optimizing the classification process. The paper showcases a comprehensive experimental setup, featuring the utilization of BCI Competition IV Dataset 2a & 2b. Detailed preprocessing steps, including filtering and feature extraction, are presented with mathematical rigor. Results demonstrate the remarkable artifact removal capabilities of FCIF and the classification prowess of FC-FBCSP combined with the Modified DNN classifier. Comparative analysis highlights the superiority of the proposed approach over baseline methods and the method achieves the mean accuracy of 98.575%.
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  • 文章类型: Journal Article
    髓鞘调节因子(MYRF)是控制中枢神经系统中髓磷脂形成和维持的主要调节因子。MYRF在后生动物中的保守性及其广泛的组织表达表明,它的功能超出了公认的髓鞘形成作用。MYRF的丧失导致无脊椎动物和脊椎动物的发育致死性。人类MYRF单倍功能不全导致MYRF相关的心脏泌尿生殖道综合征,强调其在动物发育中的重要性;然而,这些机制在很大程度上是未经探索的。MYRF,一种非常规的转录因子,开始嵌入膜中,并经历分子内伴侣介导的三聚,引发自我分裂,允许其具有Ig折叠DNA结合域的N末端片段进入细胞核进行转录调节。最近的研究表明卵裂的发育调控,然而,机制仍然是神秘的。虽然已经阐明了MYRF结构的某些部分,其他人仍然默默无闻,留下了关于这些图案如何与其复杂的处理和功能相关联的问题。
    The Myelin Regulator Factor (MYRF) is a master regulator governing myelin formation and maintenance in the central nervous system. The conservation of MYRF across metazoans and its broad tissue expression suggest it has functions extending beyond the well-established role in myelination. Loss of MYRF results in developmental lethality in both invertebrates and vertebrates, and MYRF haploinsufficiency in humans causes MYRF-related Cardiac Urogenital Syndrome, underscoring its importance in animal development; however, these mechanisms are largely unexplored. MYRF, an unconventional transcription factor, begins embedded in the membrane and undergoes intramolecular chaperone mediated trimerization, which triggers self-cleavage, allowing its N-terminal segment with an Ig-fold DNA-binding domain to enter the nucleus for transcriptional regulation. Recent research suggests developmental regulation of cleavage, yet the mechanisms remain enigmatic. While some parts of MYRF\'s structure have been elucidated, others remain obscure, leaving questions about how these motifs are linked to its intricate processing and function.
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  • 文章类型: Journal Article
    监测和预测区域地下水储量(GWS)波动是有效管理水资源的重要支持。因此,以山东省为例,重力恢复和气候实验(GRACE)和GRACE后续(GRACE-FO)的数据用于反演2003年1月至2022年12月的GWS波动以及水隙全球水文模型(WGHM),原位地下水量和水位数据。使用独立成分分析(ICA)分解时空特征,以及影响因素,如降水和人类活动,也进行了分析。为了预测GWS的短时间变化,支持向量机(SVM)与三种常用的长短期记忆方法(LSTM)结合使用,奇异谱分析(SSA),自回归移动平均模型(ARMA),作为比较。结果表明:(1)西部GWS的损失强度明显大于沿海地区。2003-2006年GWS急剧增加,2007-2014年GWS损失率为-5.80±2.28mm/a,2015-2022年GWS变化线性趋势为-5.39±3.65mm/a,可能主要受南水北调工程影响。GRACE与WGHM的相关系数为0.67,与原位地下水量和水位一致。(2)考虑移动平均线后的时间延迟,GWS与每月全球降水气候项目(GPCP)具有较高的正相关性。根据连续小波变换(CWT)方法具有相似的能量谱。此外,分析了影响GWS年度波动的因素,GWS与包括地下水开采消耗在内的原位数据之间的相关系数,农田灌溉量分别为0.80、0.71。(3)对于GWS预测,采用SVM方法进行分析,建立了三个训练样本,分别为180、204和228个月,拟合优度均高于0.97。相关系数分别为0.56、0.75、0.68;RMSE分别为5.26、4.42、5.65mm;NSE分别为0.28、0.43、0.36。SVM模型的短期预测性能优于其他方法。
    Monitoring and predicting the regional groundwater storage (GWS) fluctuation is an essential support for effectively managing water resources. Therefore, taking Shandong Province as an example, the data from Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) is used to invert GWS fluctuation from January 2003 to December 2022 together with Watergap Global Hydrological Model (WGHM), in-situ groundwater volume and level data. The spatio-temporal characteristics are decomposed using Independent Components Analysis (ICA), and the impact factors, such as precipitation and human activities, which are also analyzed. To predict the short-time changes of GWS, the Support Vector Machines (SVM) is adopted together with three commonly used methods Long Short-Term Memory (LSTM), Singular Spectrum Analysis (SSA), Auto-Regressive Moving Average Model (ARMA), as the comparison. The results show that: (1) The loss intensity of western GWS is significantly greater than those in coastal areas. From 2003 to 2006, GWS increased sharply; during 2007 to 2014, there exists a loss rate - 5.80 ± 2.28 mm/a of GWS; the linear trend of GWS change is - 5.39 ± 3.65 mm/a from 2015 to 2022, may be mainly due to the effect of South-to-North Water Diversion Project. The correlation coefficient between GRACE and WGHM is 0.67, which is consistent with in-situ groundwater volume and level. (2) The GWS has higher positive correlation with monthly Global Precipitation Climatology Project (GPCP) considering time delay after moving average, which has the similar energy spectrum depending on Continuous Wavelet Transform (CWT) method. In addition, the influencing facotrs on annual GWS fluctuation are analyzed, the correlation coefficient between GWS and in-situ data including the consumption of groundwater mining, farmland irrigation is 0.80, 0.71, respectively. (3) For the GWS prediction, SVM method is adopted to analyze, three training samples with 180, 204 and 228 months are established with the goodness-of-fit all higher than 0.97. The correlation coefficients are 0.56, 0.75, 0.68; RMSE is 5.26, 4.42, 5.65 mm; NSE is 0.28, 0.43, 0.36, respectively. The performance of SVM model is better than the other methods for the short-term prediction.
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  • 文章类型: Journal Article
    静息状态网络(RSN)的电生理基础仍在争论中。特别是,尚未确定能够同样很好地解释所有RSN的原则性机制。虽然脑磁图(MEG)和脑电图是确定RSN电生理基础的首选方法,还没有RSN的标准分析管道。在这篇文章中,我们比较了从MEG数据中提取RSN的两种主要的现有数据驱动分析策略,并介绍了第三种方法。第一种方法使用相位-振幅耦合来确定RSN。第二种方法通过对不同频段的希尔伯特包络进行独立分量分析来提取RSN,而第三种新方法使用奇异值分解代替。为了评估这些方法,我们将MEG-RSN与来自相同受试者的功能磁共振成像(fMRI)-RSN进行了比较。总的来说,可以使用所有三种技术用MEG提取RSN,与特定组的fMRI-RSN匹配。有趣的是,与两种现有方法相比,基于SVD的新方法与七个fMRI-RSN中的五个产生了显着更高的对应关系。重要的是,用这种方法,除视觉网络外,所有网络在一个频带内与fMRI网络的对应度最高.因此,我们提供了对fMRI-RSN的电生理基础的进一步见解。这些知识对于电生理连接体的分析将是重要的。
    The electrophysiological basis of resting-state networks (RSN) is still under debate. In particular, no principled mechanism has been determined that is capable of explaining all RSN equally well. While magnetoencephalography (MEG) and electroencephalography are the methods of choice to determine the electrophysiological basis of RSN, no standard analysis pipeline of RSN yet exists. In this article, we compare the two main existing data-driven analysis strategies for extracting RSNs from MEG data and introduce a third approach. The first approach uses phase-amplitude coupling to determine the RSN. The second approach extracts RSN through an independent component analysis of the Hilbert envelope in different frequency bands, while the third new approach uses a singular value decomposition instead. To evaluate these approaches, we compare the MEG-RSN to the functional magnetic resonance imaging (fMRI)-RSN from the same subjects. Overall, it was possible to extract RSN with MEG using all three techniques, which matched the group-specific fMRI-RSN. Interestingly the new approach based on SVD yielded significantly higher correspondence to five out of seven fMRI-RSN than the two existing approaches. Importantly, with this approach, all networks-except for the visual network-had the highest correspondence to the fMRI networks within one frequency band. Thereby we provide further insights into the electrophysiological underpinnings of the fMRI-RSNs. This knowledge will be important for the analysis of the electrophysiological connectome.
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