linear mixed model

线性混合模型
  • 文章类型: Journal Article
    线性混合模型(LMM)已成为遗传关联研究的标准,以解释样本中的种群分层和相关性,以减少假阳性。LMM的许多最新进展都集中在近似计算上。精确的方法仍然需要计算,没有理论保证。该计算对于多组学研究尤其具有挑战性,其中测试了成千上万种表型与数百万个遗传标记的关联。我们提出了使用迭代色散更新来适应LMM的IDUL和IDUL,其中,IDUL÷是IDUL的修改版本,可保证更新之间的可能性增加。实际上,IDUL和IDUL产生相同的结果,两者都比最先进的牛顿-拉夫逊法更有效,特别是,两者对于其他表型都非常有效,使它们成为研究多组学表型遗传决定因素的理想选择。理论上,LMM似然性是渐近单峰的,因此,梯度上升算法IDUL®是渐近精确的。可在https://github.com/单倍型/IDUL上免费获得用于遗传关联研究的IDUL和IDUL软件包。
    The linear mixed model (LMM) has become a standard in genetic association studies to account for population stratification and relatedness in the samples to reduce false positives. Much recent progresses in LMM focused on approximate computations. Exact methods remained computationally demanding and without theoretical assurance. The computation is particularly challenging for multiomics studies where tens of thousands of phenotypes are tested for association with millions of genetic markers. We present IDUL and IDUL† that use iterative dispersion updates to fit LMMs, where IDUL† is a modified version of IDUL that guarantees likelihood increase between updates. Practically, IDUL and IDUL† produced identical results, both are markedly more efficient than the state-of-the-art Newton-Raphson method, and in particular, both are highly efficient for additional phenotypes, making them ideal to study genetic determinants of multiomics phenotypes. Theoretically, the LMM likelihood is asymptotically unimodal, and therefore the gradient ascent algorithm IDUL† is asymptotically exact. A software package implementing IDUL and IDUL† for genetic association studies is freely available at https://github.com/haplotype/IDUL.
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  • 文章类型: Journal Article
    因果结构预测是否可以提高汉语句子的理解力,以及词头的位置是否可以调节预测效果,尚不确定。我们进行了一项实验,以探讨因果预测和词位在汉语句子阅读中的作用。参与者被要求阅读包含因果联系的句子,并记录他们的眼球运动。在实验中,我们操纵了句子的因果结构和词头的位置。我们发现因果结构对第一遍阅读时间有促进作用,对总阅读时间有阻碍作用。然而,该效果不是由标题位置介导的。结果表明,因果句法预测促进了汉语句子处理的早期处理,增加了汉语句子处理后期的整合成本。这些发现也支持基于约束的方法,这表明语义和句法处理之间的隔离。
    It remains uncertain whether causal structure prediction can improve comprehension in Chinese sentences and whether the position of the headword mediates the prediction effect. We conducted an experiment to explore the effect of causal prediction and headword position in Chinese sentence reading. Participants were asked to read sentences containing causal connectives with their eye movements recorded. In the experiment, we manipulated the causal structure of the sentence and the position of the headword. We found a promoting effect of causal structure on first-pass reading time and a hindering impact on total reading time. However, the effect was not mediated by the headword position. The results show that causal syntactic prediction facilitated early-stage processing and increased the integration cost in the late stage of Chinese sentence processing. These findings also support the constraint-based approach, which suggests an isolation between semantic and syntactic processing.
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  • 文章类型: Journal Article
    本文旨在评估哮喘和非哮喘儿童和青少年的空气污染暴露与第一秒用力呼气量(FEV1)之间的统计关联。其中响应变量FEV1每月重复测量,表征纵向实验。由于数据的性质,鲁棒线性混合模型(RLMM),结合稳健的主成分分析(RPCA),建议处理协变量之间的多重共线性以及极端观测值(高水平的空气污染物)对估计值的影响。考虑Huber和Tukey损失函数以获得线性混合模型(LMM)中参数的鲁棒估计。在协变量遵循线性时间序列模型的情况下,进行了有限的样本量调查,其中有和没有加性异常值(AO)。研究了时间相关性和异常值对LMM中固定效应参数估计的影响。在真实的数据分析中,稳健的模型策略证明,RPCA表现出三个主成分(PC),主要与相对湿度(Hmd)有关,直径小于10μm的颗粒物(PM10)和直径小于2.5μm的颗粒物(PM2.5)。
    This paper aims to evaluate the statistical association between exposure to air pollution and forced expiratory volume in the first second (FEV1) in both asthmatic and non-asthmatic children and teenagers, in which the response variable FEV1 was repeatedly measured on a monthly basis, characterizing a longitudinal experiment. Due to the nature of the data, an robust linear mixed model (RLMM), combined with a robust principal component analysis (RPCA), is proposed to handle the multicollinearity among the covariates and the impact of extreme observations (high levels of air contaminants) on the estimates. The Huber and Tukey loss functions are considered to obtain robust estimators of the parameters in the linear mixed model (LMM). A finite sample size investigation is conducted under the scenario where the covariates follow linear time series models with and without additive outliers (AO). The impact of the time-correlation and the outliers on the estimates of the fixed effect parameters in the LMM is investigated. In the real data analysis, the robust model strategy evidenced that RPCA exhibits three principal component (PC), mainly related to relative humidity (Hmd), particulate matter with a diameter smaller than 10 μm (PM10) and particulate matter with a diameter smaller than 2.5 μm (PM2.5).
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  • 文章类型: Journal Article
    睡眠障碍在创伤后应激障碍患者中很常见。运动干预是治疗睡眠障碍的一种有希望的方法,但对运动干预对与创伤后应激障碍相关的睡眠障碍的疗效知之甚少。共有40名患有创伤后应激障碍的人被随机分为六个阶段的高强度间歇训练或低至中强度训练。12天内服用。从基线到匹兹堡睡眠质量指数评估24天内的睡眠质量。一个睡眠日志,和腰部佩戴的活动描记术。分析显示,无论组分配如何,随着时间的推移,高强度间歇训练的匹兹堡睡眠质量指数得分显着提高了2.28分,低强度至中等强度训练的得分提高了1.70分(高强度间歇训练的d=0.56;低强度至中等强度训练的得分为0.49),而任何睡眠日志或活动记录测量均无显著变化。对受临床显着睡眠障碍影响的子样本(n=24)的分析显示,运动干预之间没有差异,具有显着的时间效应:匹兹堡睡眠质量指数在高强度间歇训练下显着提高了2.65分,在低至中强度训练下显着提高了2.89分(高强度间歇训练下为d=0.53;在低至中强度训练下为0.88),从基线到术后,高强度间歇训练和睡眠开始后的清醒肌动测量值显著降低14.39分钟,低-中强度训练分别为6.96分钟(高强度间歇训练d=0.47;低-中强度训练为0.11).在我们的试点研究中,我们发现,从评估前到评估后,睡眠质量均有改善.运动组之间没有显着差异。需要进一步的研究来调查发现的时间效应是否反映了运动干预或无关因素。
    Sleep disturbances are common in individuals with posttraumatic stress disorder. Exercise interventions are a promising approach in the treatment of sleep disorders, but little is known about the efficacy of exercise interventions for sleep disturbances associated with posttraumatic stress disorder. A total of 40 individuals with posttraumatic stress disorder were randomized to six sessions of either high-intensity interval training or low-to-moderate-intensity training, administered within 12 days. Sleep quality was assessed over 24 days from baseline to post with the Pittsburgh Sleep Quality Index, a sleep log, and a waist-worn actigraphy. Analyses revealed that, regardless of group allocation, Pittsburgh Sleep Quality Index score improved significantly by 2.28 points for high-intensity interval training and 1.70 points for low-to-moderate-intensity training (d = 0.56 for high-intensity interval training; 0.49 for low-to-moderate-intensity training) over time, while there were no significant changes in any sleep log or actigraphy measure. Analysis of a subsample of those affected by clinically significant sleep disturbances (n = 24) revealed a significant time effect with no difference between exercise interventions: Pittsburgh Sleep Quality Index improved significantly by 2.65 points for high-intensity interval training and 2.89 points for low-to-moderate-intensity training (d = 0.53 for high-intensity interval training; 0.88 for low-to-moderate-intensity training), and actigraphy measure of wake after sleep onset was reduced significantly by 14.39 minutes for high-intensity interval training and 6.96 minutes for low-to-moderate-intensity training (d = 0.47 for high-intensity interval training; 0.11 for low-to-moderate-intensity training) from baseline to post. In our pilot study, we found an improvement in sleep quality from pre- to post-assessment. There were no significant differences between exercise groups. Further studies are needed to investigate whether the found time effects reflect the exercise intervention or unrelated factors.
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  • 文章类型: Journal Article
    多个性状与多个遗传变异的联合关联分析可以提供对遗传结构和多效性的洞察,提高性状预测,并增加检测关联的能力。此外,有些特征自然是高维的,例如,images,网络,或纵向测量的特征。评估多性状遗传关联的重要性可能是具有挑战性的,特别是当样本具有群体子结构和/或相关个体时。未能充分调整样品结构会导致功率损失和膨胀1型错误,和常用的评估显著性的方法可能对大量的性状效果不佳或计算缓慢。我们开发了JASPER,一个快速的,强大,用于评估与一组遗传变异相关的多性状显著性的稳健方法,在具有人口子结构的样本中,掺合料,和/或相关性。在模拟中,JASPER拥有更高的力量,更好的类型1错误控制,和比现有方法更快的计算,随着特征数量的增加,JASPER的力量和速度优势不断增加。JASPER可能适用于广泛的关联测试应用程序,包括多种疾病特征,表达性状,图像衍生的特征,和微生物组丰富。它允许协变量,确定,和罕见的变体,并且对表型模型错误指定是稳健的。我们应用JASPER分析弗雷明汉心脏研究中的基因表达,where,与替代方法相比,JASPER发现了更重要的关联,包括几个表明多效性的效应,其中大部分复制了以前的结果,而其他人以前没有报道过。我们的结果表明JASPER有望在结构化样本中进行强大的多性状分析。
    Joint association analysis of multiple traits with multiple genetic variants can provide insight into genetic architecture and pleiotropy, improve trait prediction, and increase power for detecting association. Furthermore, some traits are naturally high-dimensional, e.g., images, networks, or longitudinally measured traits. Assessing significance for multitrait genetic association can be challenging, especially when the sample has population sub-structure and/or related individuals. Failure to adequately adjust for sample structure can lead to power loss and inflated type 1 error, and commonly used methods for assessing significance can work poorly with a large number of traits or be computationally slow. We developed JASPER, a fast, powerful, robust method for assessing significance of multitrait association with a set of genetic variants, in samples that have population sub-structure, admixture, and/or relatedness. In simulations, JASPER has higher power, better type 1 error control, and faster computation than existing methods, with the power and speed advantage of JASPER increasing with the number of traits. JASPER is potentially applicable to a wide range of association testing applications, including for multiple disease traits, expression traits, image-derived traits, and microbiome abundances. It allows for covariates, ascertainment, and rare variants and is robust to phenotype model misspecification. We apply JASPER to analyze gene expression in the Framingham Heart Study, where, compared to alternative approaches, JASPER finds more significant associations, including several that indicate pleiotropic effects, most of which replicate previous results, while others have not previously been reported. Our results demonstrate the promise of JASPER for powerful multitrait analysis in structured samples.
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  • 文章类型: Journal Article
    阿尔茨海默病(AD)负担的增加强调了对有效诊断和治疗策略的需求。尽管有针对淀粉样蛋白β(Aβ)斑块的治疗方法,疾病改善疗法仍然难以捉摸。早期发现有AD转化风险的轻度认知障碍(MCI)患者至关重要,尤其是抗Aβ治疗。虽然血浆生物标志物有望区分AD和MCI,但缺乏预测认知衰退的证据。这项研究的目的是评估血浆蛋白生物标志物是否可以预测非痴呆个体的认知下降和MCI患者向AD的转化。这项研究是韩国认知老化和痴呆纵向研究(KLOSCAD)的一部分,一个潜在的,基于社区的队列。参与者基于基线时的血浆生物标志物可用性和临床诊断。这项研究包括MCI(n=50),MCI至AD(n=21),和认知障碍(CU,n=40)参与者。六种蛋白质的基线血浆浓度-总tau(tTau),残基181处的磷酸化tau(pTau181),淀粉样β42(Aβ42),淀粉样β40(Aβ40),神经丝轻链(NFL),和胶质纤维酸性蛋白(GFAP)-以及三个衍生比率(pTau181/tTau,分析了Aβ42/Aβ40,pTau181/Aβ42)以预测六年随访期内的认知能力下降。基线蛋白质生物标志物被分层为三元(低,中间,和高),并使用线性混合模型(LMM)进行分析,以预测纵向认知变化。此外,进行Kaplan-Meier分析以辨别蛋白质生物标志物是否可以预测MCI亚组中的AD转化。这项前瞻性队列研究表明,血浆NFL可以预测迷你精神状态检查(MMSE)得分的纵向下降。在被归类为淀粉样蛋白阳性的参与者中,NFL生物标志物显示了对MMSE和韩国版阿尔茨海默病注册评估分组联盟(CERAD-TS)总分的预测性能.此外,作为基线预测器,GFAP在CERAD-TS测量中表现出与横断面认知障碍的显着关联,特别是在淀粉样蛋白阳性参与者中。Kaplan-Meier曲线分析表明NFL的预测性能,GFAP,ttau,和Aβ42/Aβ40对MCI至AD转化的影响。这项研究表明,非痴呆参与者的血浆GFAP可能反映了基线横截面CERAD-TS评分,衡量整体认知功能。相反,血浆NFL可预测淀粉样蛋白阳性参与者的MMSE和CERAD-TS评分的纵向下降.卡普兰-迈耶曲线分析表明,NFL,GFAP,ttau,和Aβ42/Aβ40是未来AD转化的潜在稳健预测因子。
    The increasing burden of Alzheimer\'s disease (AD) emphasizes the need for effective diagnostic and therapeutic strategies. Despite available treatments targeting amyloid beta (Aβ) plaques, disease-modifying therapies remain elusive. Early detection of mild cognitive impairment (MCI) patients at risk for AD conversion is crucial, especially with anti-Aβ therapy. While plasma biomarkers hold promise in differentiating AD from MCI, evidence on predicting cognitive decline is lacking. This study\'s objectives were to evaluate whether plasma protein biomarkers could predict both cognitive decline in non-demented individuals and the conversion to AD in patients with MCI. This study was conducted as part of the Korean Longitudinal Study on Cognitive Aging and Dementia (KLOSCAD), a prospective, community-based cohort. Participants were based on plasma biomarker availability and clinical diagnosis at baseline. The study included MCI (n = 50), MCI-to-AD (n = 21), and cognitively unimpaired (CU, n = 40) participants. Baseline plasma concentrations of six proteins-total tau (tTau), phosphorylated tau at residue 181 (pTau181), amyloid beta 42 (Aβ42), amyloid beta 40 (Aβ40), neurofilament light chain (NFL), and glial fibrillary acidic protein (GFAP)-along with three derivative ratios (pTau181/tTau, Aβ42/Aβ40, pTau181/Aβ42) were analyzed to predict cognitive decline over a six-year follow-up period. Baseline protein biomarkers were stratified into tertiles (low, intermediate, and high) and analyzed using a linear mixed model (LMM) to predict longitudinal cognitive changes. In addition, Kaplan-Meier analysis was performed to discern whether protein biomarkers could predict AD conversion in the MCI subgroup. This prospective cohort study revealed that plasma NFL may predict longitudinal declines in Mini-Mental State Examination (MMSE) scores. In participants categorized as amyloid positive, the NFL biomarker demonstrated predictive performance for both MMSE and total scores of the Korean version of the Consortium to Establish a Registry for Alzheimer\'s Disease Assessment Packet (CERAD-TS) longitudinally. Additionally, as a baseline predictor, GFAP exhibited a significant association with cross-sectional cognitive impairment in the CERAD-TS measure, particularly in amyloid positive participants. Kaplan-Meier curve analysis indicated predictive performance of NFL, GFAP, tTau, and Aβ42/Aβ40 on MCI-to-AD conversion. This study suggests that plasma GFAP in non-demented participants may reflect baseline cross-sectional CERAD-TS scores, a measure of global cognitive function. Conversely, plasma NFL may predict longitudinal decline in MMSE and CERAD-TS scores in participants categorized as amyloid positive. Kaplan-Meier curve analysis suggests that NFL, GFAP, tTau, and Aβ42/Aβ40 are potentially robust predictors of future AD conversion.
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  • 文章类型: Journal Article
    在药物开发过程中,效价测试在生物制品生产和销售所需的质量评估中起着重要作用。由于多种操作和生物学因素,与物理化学方法相比,在生物测定中通常观察到更高的变异性。在本文中,我们讨论了生物测定变异性的不同来源,以及如何统计估计这种变异性。此外,我们提出了一种算法来估计在给定规范下与不同运行次数及其相应的OOS率相关的可报告结果的可变性。在多种测定格式上进行数值实验,以阐明生物测定变异性的经验分布。
    During the drug development process, testing potency plays an important role in the quality assessment required for the manufacturing and marketing of biologics. Due to multiple operational and biological factors, higher variability is usually observed in bioassays compared with physicochemical methods. In this paper, we discuss different sources of bioassay variability and how this variability can be statistically estimated. In addition, we propose an algorithm to estimate the variability of reportable results associated with different numbers of runs and their corresponding OOS rates under a given specification. Numerical experiments are conducted on multiple assay formats to elucidate the empirical distribution of bioassay variability.
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  • 文章类型: Journal Article
    妄想症是一系列与恐惧相关的经历,跨越诊断类别,并受社会和认知因素的影响。社交媒体和其他类型的媒体使用与偏执狂相关的程度尚不清楚。
    我们的目标是在人内和人与人之间检查媒体使用和偏执狂之间的关联。
    参与者是409名被诊断为精神分裂症谱系或双相情感障碍的个体。测量包括基线时的社会人口统计学和临床特征,然后在30天内每天收集3次生态瞬时评估(EMA)。EMA评估了偏执狂和5种类型的媒体使用:社交媒体,电视,音乐,阅读或写作,以及其他互联网或计算机使用。使用广义线性混合模型来检查偏执狂作为每种类型的媒体使用的函数,反之亦然。
    在409名参与者中,以下子组报告了至少1次媒体使用情况:261次(63.8%)使用社交媒体,385(94.1%)看电视,292(71.4%)听音乐,191(46.7%)用于阅读或写作,280(68.5%)用于其他互联网或计算机用途。性别,小鼠群体,教育程度,精神分裂症和双相情感障碍的诊断与媒体使用的可能性有差异。社交媒体使用与偏执狂之间存在个人内在联系:使用社交媒体与偏执狂随后减少5.5%(倍数变化0.945,95%CI0.904-0.987)相关。反向关联,从偏执狂到社交媒体使用的后续变化,没有统计学意义。其他类型的培养基使用与妄想症没有显着相关。
    这项研究表明,社交媒体的使用与偏执狂的适度减少有关,也许反映了社会关系的临床益处。然而,结构劣势和个别因素可能会阻碍媒体活动的可及性,媒体使用的心理健康相关因素可能会随着使用内容和环境的变化而进一步变化。
    UNASSIGNED: Paranoia is a spectrum of fear-related experiences that spans diagnostic categories and is influenced by social and cognitive factors. The extent to which social media and other types of media use are associated with paranoia remains unclear.
    UNASSIGNED: We aimed to examine associations between media use and paranoia at the within- and between-person levels.
    UNASSIGNED: Participants were 409 individuals diagnosed with schizophrenia spectrum or bipolar disorder. Measures included sociodemographic and clinical characteristics at baseline, followed by ecological momentary assessments (EMAs) collected 3 times daily over 30 days. EMA evaluated paranoia and 5 types of media use: social media, television, music, reading or writing, and other internet or computer use. Generalized linear mixed models were used to examine paranoia as a function of each type of media use and vice versa at the within- and between-person levels.
    UNASSIGNED: Of the 409 participants, the following subgroups reported at least 1 instance of media use: 261 (63.8%) for using social media, 385 (94.1%) for watching TV, 292 (71.4%) for listening to music, 191 (46.7%) for reading or writing, and 280 (68.5%) for other internet or computer use. Gender, ethnoracial groups, educational attainment, and diagnosis of schizophrenia versus bipolar disorder were differentially associated with the likelihood of media use. There was a within-person association between social media use and paranoia: using social media was associated with a subsequent decrease of 5.5% (fold-change 0.945, 95% CI 0.904-0.987) in paranoia. The reverse association, from paranoia to subsequent changes in social media use, was not statistically significant. Other types of media use were not significantly associated with paranoia.
    UNASSIGNED: This study shows that social media use was associated with a modest decrease in paranoia, perhaps reflecting the clinical benefits of social connection. However, structural disadvantage and individual factors may hamper the accessibility of media activities, and the mental health correlates of media use may further vary as a function of contents and contexts of use.
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  • 文章类型: Letter
    暂无摘要。
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  • 文章类型: Journal Article
    血清来源的牛免疫球蛋白(SBI)通过直接结合微生物成分来防止易位和炎症。最近,SBI还通过肠道微生物组调节显示出潜在的益处。为了确认和扩展这些初步发现,SBI消化和结肠发酵使用临床预测离体SIFR®技术(针对24名成年人)进行了研究,第一次,结合宿主细胞(上皮/免疫(Caco-2/THP-1)细胞)。SBI(人类等效剂量(HED)=2和5g/天)和参考益生元菊粉(IN;HED=2g/天)显着促进肠道屏障完整性,并且比饮食蛋白质(DP)更深刻。特别是在LPS诱导的炎症。SBI还特异性降低炎症标志物(TNF-α和CXCL10)。SBI和IN均通过特定的肠道微生物增强SCFA(乙酸盐/丙酸盐/丁酸盐),而SBI特异性刺激戊酸/bCFA和吲哚-3-丙酸(促进健康的色氨酸代谢产物)。最后,由于强大的队列(n=24),治疗效果可以根据初始微生物群组成进行分层:对于分类为拟杆菌/厚壁菌型肠型供体的受试者,仅刺激(乙酸盐/不产生气体)双歧杆菌科,与高乙酸盐/低产气相吻合,因此可能对IN具有更好的耐受性。总之,这项研究强烈表明肠道微生物组调节是SBI促进健康的机制。此外,SIFR®技术被证明是对治疗反应进行分层和支持未来个性化营养方法的强大工具.
    Serum-derived bovine immunoglobulin (SBI) prevents translocation and inflammation via direct binding of microbial components. Recently, SBI also displayed potential benefits through gut microbiome modulation. To confirm and expand upon these preliminary findings, SBI digestion and colonic fermentation were investigated using the clinically predictive ex vivo SIFR® technology (for 24 human adults) that was, for the first time, combined with host cells (epithelial/immune (Caco-2/THP-1) cells). SBI (human equivalent dose (HED) = 2 and 5 g/day) and the reference prebiotic inulin (IN; HED = 2 g/day) significantly promoted gut barrier integrity and did so more profoundly than a dietary protein (DP), especially upon LPS-induced inflammation. SBI also specifically lowered inflammatory markers (TNF-α and CXCL10). SBI and IN both enhanced SCFA (acetate/propionate/butyrate) via specific gut microbes, while SBI specifically stimulated valerate/bCFA and indole-3-propionic acid (health-promoting tryptophan metabolite). Finally, owing to the high-powered cohort (n = 24), treatment effects could be stratified based on initial microbiota composition: IN exclusively stimulated (acetate/non-gas producing) Bifidobacteriaceae for subjects classifying as Bacteroides/Firmicutes-enterotype donors, coinciding with high acetate/low gas production and thus likely better tolerability of IN. Altogether, this study strongly suggests gut microbiome modulation as a mechanism by which SBI promotes health. Moreover, the SIFR® technology was shown to be a powerful tool to stratify treatment responses and support future personalized nutrition approaches.
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