Linear regression

线性回归
  • 文章类型: Journal Article
    体内宽场荧光成像(WFFI)数据的准确解释需要将原始荧光信号精确分离成神经和血液动力学成分。经典的基于比尔-兰伯特定律的方法,它使用同时的530-nm照明来估计脑血容量(CBV)的相对变化,未能解释来自非神经元成分的530nm光子的散射和反射,导致对CBV变化的偏倚估计以及随后的神经活动的错误表示。本研究引入了一种新颖的线性回归方法,旨在克服这一限制。这种校正提供了荧光数据中CBV变化和神经活动的更可靠表示。我们的方法在多个数据集上进行了验证,证明了它比经典方法的优越性。
    Accurate interpretation of in vivo wide-field fluorescent imaging (WFFI) data requires precise separation of raw fluorescence signals into neural and hemodynamic components. The classical Beer-Lambert law-based approach, which uses concurrent 530-nm illumination to estimate relative changes in cerebral blood volume (CBV), fails to account for the scattering and reflection of 530-nm photons from non-neuronal components leading to biased estimates of CBV changes and subsequent misrepresentation of neural activity. This study introduces a novel linear regression approach designed to overcome this limitation. This correction provides a more reliable representation of CBV changes and neural activity in fluorescence data. Our method is validated across multiple datasets, demonstrating its superiority over the classical approach.
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  • 文章类型: Journal Article
    目的:为高精度的三维人脑成像提供基于导航器的运行时运动和一阶场校正,最小的校准和采集,和快速处理。
    方法:扩展了具有反馈控制的复值线性扰动模型,以使用轨道导航器(2.3ms)对梯度匀场进行估计和校正。提出了两种使模型对梯度场敏感的方法,一个基于有限的差异与三个额外的导航员,和另一个基于投影的近似,不需要额外的导航器。提出并评估了矩阵和数据的噪声去相关机制,以减少不必要的参数偏差。
    结果:刚性运动和一阶场控制实现了鲁棒的运动和梯度匀场校正,从而在一系列体模和不同场条件的体内实验中提高了图像质量。在幻影扫描中,磁铁漂移,成功校正了第二瓶体模移位引起的强制梯度场扰动和场畸变。磁体漂移的场估计与同时进行的场探针测量非常吻合。对于体内扫描,所提出的方法减轻了躯干运动的场变化,同时对头部运动具有鲁棒性。体内梯度场精度为30nT/m$30\\;\\mathrm{nT}/\\mathrm{m}$$以及单位数测微计和毫度刚性精度。
    结论:基于导航器的方法实现了准确的,具有低序列影响和校准要求的高精度运行时运动和场校正。
    OBJECTIVE: To provide a navigator-based run-time motion and first-order field correction for three-dimensional human brain imaging with high precision, minimal calibration and acquisition, and fast processing.
    METHODS: A complex-valued linear perturbation model with feedback control is extended to estimate and correct for gradient shim fields using orbital navigators (2.3 ms). Two approaches for sensitizing the model to gradient fields are presented, one based on finite differences with three additional navigators, and another projection-based approximation requiring no additional navigators. A mechanism for noise decorrelation of the matrix and the data is proposed and evaluated to reduce unwanted parameter biases.
    RESULTS: The rigid motion and first-order field control achieves robust motion and gradient shim corrections improving image quality in a series of phantom and in vivo experiments with varying field conditions. In phantom scans, magnet drifts, forced gradient field perturbations and field distortions from shifts of a second bottle phantom are successfully corrected. Field estimates of the magnet drifts are in good agreement with concurrent field probe measurements. For in vivo scans, the proposed method mitigates field variations from torso motions while being robust to head motion. In vivo gradient field precisions were 30   nT / m $$ 30\\;\\mathrm{nT}/\\mathrm{m} $$ along with single-digit micrometer and millidegree rigid precisions.
    CONCLUSIONS: The navigator-based method achieves accurate, high-precision run-time motion and field corrections with low sequence impact and calibration requirements.
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  • 文章类型: Journal Article
    神经成像数据模型(NIDM)是一系列规范,用于描述从原始数据到分析和来源的神经成像数据生命周期的各个方面。NIDM使用社区驱动的术语以及资源描述框架(RDF)文档中明确的数据字典来描述用于集成和查询的数据和元数据。来自不同研究的数据,使用本地定义的变量名,可以通过将它们链接到已建立的本体和术语中的高阶概念来检索。通过这些能力,NIDM文档有望提高可重复性,并促进数据发现和重用。PyNIDM是一个支持创建的Python工具箱,操纵,和查询NIDM文档。使用PyNIDM中可用的查询工具,用户能够询问数据集以找到收集了测量相似表型特性的变量的研究。这个,反过来,促进跨多个研究的数据转换和组合。本手稿的重点是线性回归工具,它是PyNIDM工具箱的一部分,直接在NIDM文档上工作。它提供了一个高层次的统计分析,帮助研究人员更深入地了解他们正在考虑在研究中合并的数据。这节省了研究人员宝贵的时间和精力,同时显示变量之间的潜在关系。线性回归工具通过与其他工具(pynidm线性回归)集成的命令行界面进行操作,并为用户提供了使用可用于NIDM文档的丰富查询技术指定感兴趣的变量的机会,然后进行具有可选的对比度和正则化的线性回归。
    The Neuroimaging Data Model (NIDM) is a series of specifications for describing all aspects of the neuroimaging data lifecycle from raw data to analyses and provenance. NIDM uses community-driven terminologies along with unambiguous data dictionaries within a Resource Description Framework (RDF) document to describe data and metadata for integration and query. Data from different studies, using locally defined variable names, can be retrieved by linking them to higher-order concepts from established ontologies and terminologies. Through these capabilities, NIDM documents are expected to improve reproducibility and facilitate data discovery and reuse. PyNIDM is a Python toolbox supporting the creation, manipulation, and querying of NIDM documents. Using the query tools available in PyNIDM, users are able interrogate datasets to find studies that have collected variables measuring similar phenotypic properties. This, in turn, facilitates the transformation and combination of data across multiple studies. The focus of this manuscript is the linear regression tool which is a part of the PyNIDM toolbox and works directly on NIDM documents. It provides a high-level statistical analysis that aids researchers in gaining more insight into the data that they are considering combining across studies. This saves researchers valuable time and effort while showing potential relationships between variables. The linear regression tool operates through a command-line interface integrated with the other tools (pynidm linear-regression) and provides the user with the opportunity to specify variables of interest using the rich query techniques available for NIDM documents and then conduct a linear regression with optional contrast and regularization.
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  • 文章类型: Journal Article
    目的:Delta胆红素(白蛋白共价结合胆红素)可能在识别结合胆红素的肝排泄受损方面提供重要的临床应用,但它不能在临床实验室中实时测量用于诊断目的。
    方法:共收集了210个样本,使用高效液相色谱法测量其δ胆红素水平四次。收集的数据包括年龄,性别,诊断代码,δ胆红素,总胆红素,直接胆红素,总蛋白质,白蛋白,球蛋白,天冬氨酸转氨酶,丙氨酸转氨酶,碱性磷酸酶,γ-谷氨酰转移酶,乳酸脱氢酶,血红蛋白,血清溶血值,溶血指数,翼值(IV),黄疸指数(II),血脂值(Lv),和血脂指数。进行特征选择,确定变量的最优组合,线性回归机器学习进行了1000次。
    结果:选择的变量是总胆红素,直接胆红素,总蛋白质,白蛋白,血红蛋白,Iv,二,还有Lv.白蛋白-直接胆红素-血红蛋白-Iv-Lv的组合可实现高δ胆红素浓度的最佳预测性能。由这些变量组成的最终方程式如下:δ胆红素=0.35×Iv0.05×Lv-0.23×直接胆红素-0.05×血红蛋白-0.04×白蛋白0.10。
    结论:本研究中建立的方程是实用的,可以轻松地在临床实验室中实时应用。
    OBJECTIVE: Delta bilirubin (albumin-covalently bound bilirubin) may provide important clinical utility in identifying impaired hepatic excretion of conjugated bilirubin, but it cannot be measured in real-time for diagnostic purposes in clinical laboratories.
    METHODS: A total of 210 samples were collected, and their delta bilirubin levels were measured four times using high-performance liquid chromatography. Data collected included age, sex, diagnosis code, delta bilirubin, total bilirubin, direct bilirubin, total protein, albumin, globulin, aspartate aminotransferase, alanine transaminase, alkaline phosphatase, gamma-glutamyl transferase, lactate dehydrogenase, hemoglobin, serum hemolysis value, hemolysis index, icterus value (Iv), icterus index (Ii), lipemia value (Lv), and lipemia index. To conduct feature selection and identify the optimal combination of variables, linear regression machine learning was performed 1,000 times.
    RESULTS: The selected variables were total bilirubin, direct bilirubin, total protein, albumin, hemoglobin, Iv, Ii, and Lv. The best predictive performance for high delta bilirubin concentrations was achieved with the combination of albumin-direct bilirubin-hemoglobin-Iv-Lv. The final equation composed of these variables was as follows: delta bilirubin = 0.35 × Iv + 0.05 × Lv - 0.23 × direct bilirubin - 0.05 × hemoglobin - 0.04 × albumin + 0.10.
    CONCLUSIONS: The equation established in this study is practical and can be easily applied in real-time in clinical laboratories.
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  • 文章类型: Journal Article
    线性混合效应(LME)模型是强大的统计工具,已在许多不同的实际应用中使用,例如零售数据分析。营销测量,和医学研究。统计推断通常通过最大似然估计进行,并对随机效应进行正态假设。然而,对于零售行业的许多应用,当考虑未知参数\'业务解释时,通常需要考虑随机效应的非正态分布。出于这种需要,研究了一种可能具有非正态分布的线性混合效应模型。我们基于因变量概率密度函数的鞍点逼近(SA),提出了一个通用的估计框架,这导致了约束非线性优化问题。然后,可以将具有正态假设的经典LME模型视为所提出的通用SA框架下的特例。与现有方法相比,所提出的方法通过令人满意的模型拟合提高了估计的现实可解释性。
    Linear Mixed Effects (LME) models are powerful statistical tools that have been employed in many different real-world applications such as retail data analytics, marketing measurement, and medical research. Statistical inference is often conducted via maximum likelihood estimation with Normality assumptions on the random effects. Nevertheless, for many applications in the retail industry, it is often necessary to consider non-Normal distributions on the random effects when considering the unknown parameters\' business interpretations. Motivated by this need, a linear mixed effects model with possibly non-Normal distribution is studied in this research. We propose a general estimating framework based on a saddlepoint approximation (SA) of the probability density function of the dependent variable, which leads to constrained nonlinear optimization problems. The classical LME model with Normality assumption can then be viewed as a special case under the proposed general SA framework. Compared with the existing approach, the proposed method enhances the real-world interpretability of the estimates with satisfactory model fits.
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  • 文章类型: Journal Article
    背景:COVID-19保护行为是世界卫生组织(WHO)建议的预防COVID-19传播的关键干预措施。然而,实现遵守这一建议通常是具有挑战性的,特别是在社会弱势群体中。
    目的:我们制定了社会脆弱性指数(SVI),以预测个人遵守世卫组织关于COVID-19保护性行为建议的倾向,并确定随着Omicron在2022年1月至2022年8月期间在非洲国家和2021年8月至2022年6月期间在亚太国家的演变,社会脆弱性的变化。
    方法:在非洲国家,在第一次Omicron波期间,从14个国家(n=15,375)收集了基线数据,随访数据来自7个国家(n=7179)。在亚太国家,在第一次Omicron波之前,从14个国家(n=12,866)收集了基线数据,随访数据来自9个国家(n=8737)。从相关数据库检索国家的社会经济和健康概况。要为4个数据集中的每个数据集构建SVI,与COVID-19保护行为相关的变量被纳入使用多脉络线相关性和varimax旋转的因子分析中.对影响因素进行了基数调整,求和,和最小值-最大值从0归一化到1(最脆弱到最不脆弱)。遵守世卫组织建议的分数是使用个人自我报告的针对COVID-19的保护行为计算的。使用多元线性回归分析来评估SVI与对WHO建议的依从性评分之间的关联,以验证该指数。
    结果:在非洲,导致社会脆弱性的因素包括识字和媒体使用,对医护人员和政府的信任,国家收入和基础设施。在亚太地区,社会脆弱性是由识字决定的,国家收入和基础设施,和人口密度。该指数与非洲国家在两个时间点遵守世卫组织建议有关,但仅在亚太国家的后续行动期间。在基线,非洲国家的指数值在13个国家从0.00到0.31之间,1个国家的指数值为1.00。亚太国家的指数值在12个国家从0.00到0.23之间,2个国家的指数值为0.79和1.00。在后续阶段,7个非洲国家中的6个和2个最脆弱的亚太国家的指数值下降。两个区域最脆弱国家的指数值保持不变。
    结论:在这两个地区,在基线时观察到社会对遵守世卫组织建议的脆弱性存在显著不平等,在第一次Omicron波之后,间隙变得更大。了解影响社会对COVID-19保护性行为的脆弱性的维度可能会支持有针对性的干预措施,以增强对WHO建议的遵守,并减轻弱势群体未来大流行的影响。
    BACKGROUND: COVID-19 protective behaviors are key interventions advised by the World Health Organization (WHO) to prevent COVID-19 transmission. However, achieving compliance with this advice is often challenging, particularly among socially vulnerable groups.
    OBJECTIVE: We developed a social vulnerability index (SVI) to predict individuals\' propensity to adhere to the WHO advice on protective behaviors against COVID-19 and identify changes in social vulnerability as Omicron evolved in African countries between January 2022 and August 2022 and Asia Pacific countries between August 2021 and June 2022.
    METHODS: In African countries, baseline data were collected from 14 countries (n=15,375) during the first Omicron wave, and follow-up data were collected from 7 countries (n=7179) after the wave. In Asia Pacific countries, baseline data were collected from 14 countries (n=12,866) before the first Omicron wave, and follow-up data were collected from 9 countries (n=8737) after the wave. Countries\' socioeconomic and health profiles were retrieved from relevant databases. To construct the SVI for each of the 4 data sets, variables associated with COVID-19 protective behaviors were included in a factor analysis using polychoric correlation with varimax rotation. Influential factors were adjusted for cardinality, summed, and min-max normalized from 0 to 1 (most to least vulnerable). Scores for compliance with the WHO advice were calculated using individuals\' self-reported protective behaviors against COVID-19. Multiple linear regression analyses were used to assess the associations between the SVI and scores for compliance to WHO advice to validate the index.
    RESULTS: In Africa, factors contributing to social vulnerability included literacy and media use, trust in health care workers and government, and country income and infrastructure. In Asia Pacific, social vulnerability was determined by literacy, country income and infrastructure, and population density. The index was associated with compliance with the WHO advice in both time points in African countries but only during the follow-up period in Asia Pacific countries. At baseline, the index values in African countries ranged from 0.00 to 0.31 in 13 countries, with 1 country having an index value of 1.00. The index values in Asia Pacific countries ranged from 0.00 to 0.23 in 12 countries, with 2 countries having index values of 0.79 and 1.00. During the follow-up phase, the index values decreased in 6 of 7 African countries and the 2 most vulnerable Asia Pacific countries. The index values of the least vulnerable countries remained unchanged in both regions.
    CONCLUSIONS: In both regions, significant inequalities in social vulnerability to compliance with WHO advice were observed at baseline, and the gaps became larger after the first Omicron wave. Understanding the dimensions that influence social vulnerability to protective behaviors against COVID-19 may underpin targeted interventions to enhance compliance with WHO recommendations and mitigate the impact of future pandemics among vulnerable groups.
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  • 文章类型: Journal Article
    为了提高预测性能并减少拉曼光谱中的伪影,我们开发了一种极限梯度增强(XGBoost)预处理方法来预处理葡萄糖的拉曼光谱,甘油和乙醇的混合物。为保证XGBoost预处理方法的鲁棒性和可靠性,开发了X-LR模型(结合了XGBoost预处理和线性回归(LR)模型)和X-MLP模型(结合了XGBoost预处理和多层感知器(MLP)模型)。这两个模型用于定量分析葡萄糖的浓度,混合溶液的拉曼光谱中的甘油和乙醇。在X-LR模型和X-MLP模型中,首先利用超参数比例图缩小超参数的搜索范围。然后相关系数(R2),校准均方根(RMSEC),和预测均方根误差(RMSEP)用于评估模型的性能。实验结果表明,XGBoost预处理方法具有较高的精度和泛化能力,与其他预处理方法相比,LR和MLP模型的性能更好。
    To improve prediction performance and reduce artifacts in Raman spectra, we developed an eXtreme Gradient Boosting (XGBoost) preprocessing method to preprocess the Raman spectra of glucose, glycerol and ethanol mixtures. To ensure the robustness and reliability of the XGBoost preprocessing method, an X-LR model (which combined XGBoost preprocessing and a linear regression (LR) model) and a X-MLP model (which combined XGBoost preprocessing and a multilayer perceptron (MLP) model) were developed. These two models were used to quantitatively analyze the concentrations of glucose, glycerol and ethanol in the Raman spectra of mixed solutions. The proportion map of hyperparameters was firstly used to narrow down the search range of hyperparameters in the X-LR and the X-MLP models. Then the correlation coefficients (R2), root mean square of calibration (RMSEC), and root mean square error of prediction (RMSEP) were used to evaluate the models\' performance. Experimental results indicated that the XGBoost preprocessing method achieved higher accuracy and generalization capability, with better performance than those of other preprocessing methods for both LR and MLP models.
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  • 文章类型: Journal Article
    根据主要基于视觉特性的标准建立蔬菜质量参数。尽管了解植物在整个发育过程中次生代谢的生化变化对于指导消费决策至关重要,收获和加工,这些决定涉及试剂的使用,特定的设备和先进的技术,让它们变得缓慢和昂贵。然而,当采用非破坏性方法来预测此类确定时,可以以足够的精度测试更多的样品。因此,这项工作的目的是建立能够在非破坏性物理和比色方面(预测变量)和破坏性测定生物活性化合物和抗氧化活性(要预测的变量)之间进行建模的关联,在成熟过程中,用分光光度法和高效液相色谱法对纳米香蕉进行定量。验证了对类黄酮等参数的预测,使用预测参数的回归方程表明R2的重要性,从83.43到98.25%不等,表明一些非破坏性参数可以作为预测因子非常有效。
    Vegetable quality parameters are established according to standards primarily based on visual characteristics. Although knowledge of biochemical changes in the secondary metabolism of plants throughout development is essential to guide decision-making about consumption, harvesting and processing, these determinations involve the use of reagents, specific equipment and sophisticated techniques, making them slow and costly. However, when non-destructive methods are employed to predict such determinations, a greater number of samples can be tested with adequate precision. Therefore, the aim of this work was to establish an association capable of modeling between non-destructive-physical and colorimetric aspects (predictive variables)-and destructive determinations-bioactive compounds and antioxidant activity (variables to be predicted), quantified spectrophotometrically and by HPLC in \'Nanicão\' bananas during ripening. It was verified that to predict some parameters such as flavonoids, a regression equation using predictive parameters indicated the importance of R2, which varied from 83.43 to 98.25%, showing that some non-destructive parameters can be highly efficient as predictors.
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  • 文章类型: Journal Article
    目标:助产士容易因工作的生理和情感要求而产生倦怠。职业倦怠是一种影响深远的职业现象。
    目的:本研究旨在评估埃塞俄比亚西北部公立医院助产士的职业倦怠程度和预测因素。
    方法:2022年2月7日至4月30日进行了一项基于机构的横断面研究。采用简单随机抽样方法,纳入640名研究参与者。数据是使用自我管理的问卷收集的,输入Epi-data4.6软件,并导出到SPSS版本25进行分析。采用多元线性回归分析模型来确定助产士职业倦怠的影响因素。
    结果:助产士职业倦怠的总患病率为55.3%(95%CI=51.7-58.9)。个人的普遍性,工作相关,与客户相关的倦怠为58.3%,60.3%,55.5%,分别。与倦怠显着相关的因素包括工作场所暴力(β=5.02,CI:2.90,7.13),未接受训练(β=4.32CI:1.81,6.80),暴露于血液和体液或针刺伤(β=5.13CI:3.12,7.13),低优支撑位(β=5.13CI:1.94,5.30),在三级医院工作(β=12.77CI:9.48,16.06),和六个月或更短的工作轮换(β=16.75,CI:13.12,20.39)。
    结论:这项研究发现,助产士的职业倦怠患病率明显较高。解决职业倦怠需要实施有效的职业倦怠预防措施,包括加强管理支持,提供专业培训,创造有利的工作环境,并遵守标准预防措施。
    OBJECTIVE: Midwives are susceptible to burnout due to the physically and emotionally demanding nature of their job. Burnout is an occupational phenomenon with far-reaching consequences.
    OBJECTIVE: This study aimed to assess the magnitude of burnout and predictors among midwives working at public hospitals in northwest Ethiopia.
    METHODS: An institutional-based cross-sectional study was conducted from February 7 to April 30, 2022. A simple random sampling method was employed to include 640 study participants. Data were collected using a self-administered questionnaire, entered into Epi-data 4.6 software, and exported to SPSS version 25 for analysis. A multivariable linear regression analysis model was fitted to identify factors contributing to midwives\' burnout.
    RESULTS: The overall prevalence of midwives\' burnout was 55.3 % (95 % CI = 51.7-58.9). The prevalence of personal, work-related, and client-related burnout was 58.3 %, 60.3 %, and 55.5 %, respectively. Factors that were significantly associated with burnout includes workplace violence (β = 5.02, CI: 2.90, 7.13), not receiving training (β = 4.32 CI: 1.81, 6.80), being exposed to blood and body fluids or needle stick injuries (β = 5.13 CI: 3.12, 7.13), low superior support (β = 5.13 CI: 1.94, 5.30), working in tertiary hospitals (β = 12.77 CI: 9.48, 16.06), and job rotation of six months or less (β = 16.75, CI: 13.12, 20.39).
    CONCLUSIONS: This study found that the prevalence of burnout among midwives was significantly high. Addressing burnout requires implementing effective burnout prevention measures including enhancing management support, offering professional training, creating a conducive working environment, and adhering to standard precautions.
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  • 文章类型: Journal Article
    心力衰竭(HF)定义为心脏无法满足身体的需氧量,需要提高左心室充盈压(LVP)来补偿。LVP增加可以在心导管实验室评估,但这一过程是侵入性和耗时的,以至于医生相当依赖非侵入性诊断工具。在这项工作中,我们评估了开发新的机器学习(ML)方法来预测临床相关LVP指数的可行性.同步侵入性(压力-容积描记)和非侵入性信号(ECG,脉搏血氧饱和度,和心音)从麻醉中收集,闭胸哥廷根小型猪。动物是健康的或患有具有降低的射血分数的HF,并且在对每只动物的分析中包括大约500次心跳。ML算法对LVP指数估计的预测效果很好,例如,舒张末期压的R2为0.955。这种新颖的ML算法可以帮助临床医生护理HF患者。
    Heart failure (HF) is defined as the inability of the heart to meet body oxygen demand requiring an elevation in left ventricular filling pressures (LVP) to compensate. LVP increase can be assessed in the cardiac catheterization laboratory, but this procedure is invasive and time-consuming to the extent that physicians rather rely on non-invasive diagnostic tools. In this work, we assess the feasibility to develop a novel machine-learning (ML) approach to predict clinically relevant LVP indices. Synchronized invasive (pressure-volume tracings) and non-invasive signals (ECG, pulse oximetry, and cardiac sounds) were collected from anesthetized, closed-chest Göttingen minipigs. Animals were either healthy or had HF with reduced ejection fraction and circa 500 heartbeats were included in the analysis for each animal. The ML algorithm showed excellent prediction of LVP indices estimating, for instance, the end-diastolic pressure with a R2 of 0.955. This novel ML algorithm could assist clinicians in the care of HF patients.
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