randomization

随机化
  • 文章类型: Journal Article
    研究空间-社会界面需要区分社会和空间互动驱动因素的工具。测试有关决定动物相互作用的因素的假设通常涉及将观察到的相互作用与参考或“空”模型进行比较。在参考模型中考虑社会互动的空间驱动因素的一种方法是随机化动物运动路径,以分离空间和社会表型,同时保持环境对运动的影响。这里,我们更新了一个参考模型,该模型在空间约束的影响之上检测社会吸引力。我们探索了“环绕”方法的使用,并将其性能与使用基于代理的模拟的先前方法进行了比较。环绕方法提供了与原始跟踪数据更相似的参考模型,同时仍然区分社会和空间驱动因素。此外,环绕式方法比其前身产生的假阳性更少,尤其是当动物每晚不返回一个地方而是改变运动焦点时,局部或定向。最后,我们表明,GPS跟踪的格里芬秃鹰(Gypsfulvus)之间的相互作用来自社会吸引力,而不是来自其运动的空间限制。最后,我们强调了更新的方法可能最适合测试有关社交互动根本原因的假设的生物学情况。本文是主题问题“空间-社会界面:理论和实证整合”的一部分。
    Studying the spatial-social interface requires tools that distinguish between social and spatial drivers of interactions. Testing hypotheses about the factors determining animal interactions often involves comparing observed interactions with reference or \'null\' models. One approach to accounting for spatial drivers of social interactions in reference models is randomizing animal movement paths to decouple spatial and social phenotypes while maintaining environmental effects on movements. Here, we update a reference model that detects social attraction above the effect of spatial constraints. We explore the use of our \'wrap-around\' method and compare its performance to the previous approach using agent-based simulations. The wrap-around method provides reference models that are more similar to the original tracking data, while still distinguishing between social and spatial drivers. Furthermore, the wrap-around approach results in fewer false-positives than its predecessor, especially when animals do not return to one place each night but change movement foci, either locally or directionally. Finally, we show that interactions among GPS-tracked griffon vultures (Gyps fulvus) emerge from social attraction rather than from spatial constraints on their movements. We conclude by highlighting the biological situations in which the updated method might be most suitable for testing hypotheses about the underlying causes of social interactions. This article is part of the theme issue \'The spatial-social interface: a theoretical and empirical integration\'.
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  • 文章类型: Journal Article
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  • 文章类型: Journal Article
    目的:本研究旨在评估治疗维生素D缺乏对耐药性癫痫的影响。
    方法:我们进行了多中心,双盲,安慰剂对照,随机临床试验,包括年龄≥15岁的耐药局灶性或全身性癫痫患者。25-羟基维生素D(25[OH]D)<30ng/mL的患者被随机分为接受维生素D3(胆钙化醇,100000IU,在3个月内服用5剂)或对照组(CG)接受匹配的安慰剂。在开放标签研究期间,EG患者接受100000IU/月治疗6个月,而CG患者在3个月内接受5次剂量,然后1次/月,持续3个月。监测包括癫痫发作频率(SF),25(OH)D,钙,白蛋白,肌酐检测,和标准化的疲劳量表,焦虑抑郁,和生活质量(修改后的疲劳影响量表[M-FIS],医院焦虑抑郁量表,癫痫的生活质量[QOLIE-31])在3、6和12个月。主要疗效结果是与参考期和3个月时的CG相比,SF降低的百分比。次要结果是SF和双侧强直阵挛性癫痫发作(BTCS)减少,量表分数变化,随访期间与25(OH)D的相关性。
    结果:本研究纳入了88名患者(56名女性,17-74岁),每3个月的中位基线SF=16.5和≥2种抗癫痫药物,占88.6%。在75名患者(85%)中,25(OH)D<30ng/mL;其中40个随机分配给EG,34个随机分配给CG。在3个月的盲期之后,SF降低在组间没有显著差异。然而,在开放标签期间,SF显著降低(SF中位数降低30%,12个月时的应答率为33%)。BTCS减少了52%。M-FIS和QOLIE-31评分在全组水平上显著提高。SF降低与25(OH)D>30ng/mL持续>6个月相关。
    结论:尽管在3个月的盲期后没有证实的效果,开放标签研究表明,长期补充维生素D3和最佳25(OH)D可能会降低SF和BTCS,对疲劳和生活质量有积极影响。这些发现需要进一步的长期研究来证实。
    背景:ClinicalTrials.gov标识符:NCT03475225(03-22-2018)。
    OBJECTIVE: This study was undertaken to assess the effect of treatment of vitamin D deficiency in drug-resistant epilepsy.
    METHODS: We conducted a multicenter, double-blind, placebo-controlled, randomized clinical trial, including patients aged ≥15 years with drug-resistant focal or generalized epilepsy. Patients with 25-hydroxyvitamin D (25[OH]D) < 30 ng/mL were randomized to an experimental group (EG) receiving vitamin D3 (cholecalciferol, 100 000 IU, five doses in 3 months) or a control group (CG) receiving matched placebo. During the open-label study, EG patients received 100 000 IU/month for 6 months, whereas CG patients received five doses in 3 months then 1/month for 3 months. Monitoring included seizure frequency (SF), 25(OH)D, calcium, albumin, creatinine assays, and standardized scales for fatigue, anxiety-depression, and quality of life (Modified Fatigue Impact Scale [M-FIS], Hospital Anxiety and Depression Scale, Quality of Life in Epilepsy [QOLIE-31]) at 3, 6, and 12 months. The primary efficacy outcome was the percentage of SF reduction compared to the reference period and CG at 3 months. Secondary outcomes were SF and bilateral tonic-clonic seizure (BTCS) reduction, scale score changes, and correlations with 25(OH)D during the follow-up.
    RESULTS: Eighty-eight patients were enrolled in the study (56 females, aged 17-74 years), with median baseline SF per 3 months = 16.5 and ≥2 antiseizure medications in 88.6%. In 75 patients (85%), 25(OH)D was <30 ng/mL; 40 of them were randomly assigned to EG and 34 to CG. After the 3-month blinded period, SF reduction did not significantly differ between groups. However, during the open-label period, SF significantly decreased (30% median SF reduction, 33% responder rate at 12 months). BTCSs were reduced by 52%. M-FIS and QOLIE-31 scores were significantly improved at the whole group level. SF reduction correlated with 25(OH)D > 30 ng/mL for >6 months.
    CONCLUSIONS: Despite no proven effect after the 3-month blinded period, the open-label study suggests that long-term vitamin D3 supplementation with optimal 25(OH)D may reduce SF and BTCSs, with a positive effect on fatigue and quality of life. These findings need to be confirmed by further long-term studies.
    BACKGROUND: ClinicalTrials.gov identifier: NCT03475225 (03-22-2018).
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  • 文章类型: Journal Article
    背景:观察性研究发现血脂水平与子宫内膜异位症(EM)的发展和进展之间存在相关性。然而,这种相关性的因果关系和方向尚不清楚。本研究旨在使用公开的全基因组关联研究(GWAS)汇总统计数据来检查血脂谱与EM风险之间的双向联系。
    方法:合格的暴露变量,如甘油三酯(TG)水平,总胆固醇(TC),低密度脂蛋白(LDL),和高密度脂蛋白(HDL)是在一系列质量控制程序后,使用双样本孟德尔随机化(MR)分析方法选择的。EM数据来自芬兰公开的欧洲患者数据库。反向方差加权(IVW),Egger先生,加权中位数,采用加权模式方法分析脂质暴露与EM之间的因果关系,排除混杂因素,执行灵敏度分析,并评估结果的稳定性。使用EM作为暴露和脂质结果作为研究结果进行反向MR分析。
    结果:IVW分析结果确定HDL是EM的保护因素,而TG被证明是EM的危险因素。基于EM病变部位的亚组分析确定HDL是子宫EM的保护因素,虽然TG被确定为输卵管EM的危险因素,子房,和盆腔腹膜.反向分析未显示EM对脂质水平的任何影响。
    结论:血脂,如HDL和TG,可能在EM的发生发展中起重要作用。然而,EM不会导致血脂异常。
    BACKGROUND: Observational studies have found a correlation between the levels of blood lipids and the development and progression of endometriosis (EM). However, the causality and direction of this correlation is unclear. This study aimed to examine the bidirectional connection between lipid profiles and the risk of EM using publicly available genome-wide association study (GWAS) summary statistics.
    METHODS: Eligible exposure variables such as levels of triglycerides (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) were selected using a two-sample Mendelian randomization (MR) analysis method following a series of quality control procedures. Data on EM were obtained from the publicly available Finnish database of European patients. Inverse variance weighted (IVW), MR Egger, weighted median, and weighted mode methods were used to analyze the causal relationship between lipid exposure and EM, exclude confounders, perform sensitivity analyses, and assess the stability of the results. Reverse MR analyses were performed with EM as exposure and lipid results as study outcomes.
    RESULTS: IVW analysis results identified HDL as a protective factor for EM, while TG was shown to be a risk factor for EM. Subgroup analyses based on the site of the EM lesion identified HDL as a protective factor for EM of the uterus, while TG was identified a risk factor for the EM of the fallopian tube, ovary, and pelvic peritoneum. Reverse analysis did not reveal any effect of EM on the levels of lipids.
    CONCLUSIONS: Blood lipids, such as HDL and TG, may play an important role in the development and progression of EM. However, EM does not lead to dyslipidemia.
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  • 文章类型: English Abstract
    Criteria for assessment of the significance of scientific articles are presented. The focus is on research design and methodology, illustrated by the classical study on prehospital volume treatment of severely injured individuals with penetrating torso injuries by Bickell et al. (1994). A well-thought out research design is crucial for the success of a scientific study and is documented in a study protocol beforehand. A hypothesis is a provisional explanation or prediction and must be testable, falsifiable, precise, and relevant. There are various types of randomization methods, with the randomized controlled trial being the gold standard for clinical interventional studies. When reading a scientific article it is important to verify whether the research design and setting align with the research question and whether potential sources of error have been considered and controlled. Critical scrutiny should also be applied to references, the funding and expertise of the researchers.
    UNASSIGNED: Kriterien zur Einordnung der Aussagekraft wissenschaftlicher Artikel werden vorgestellt. Der Fokus liegt auf Forschungsdesign und Methodik, die anhand der klassischen Studie zur prähospitalen Volumentherapie bei Schwerverletzten mit penetrierenden Torsoverletzungen von Bickell et al. (1994) erläutert werden. Ein sorgfältig durchdachtes Forschungsdesign entscheidet über den Erfolg einer wissenschaftlichen Studie und wird vorab im Studienprotokoll festgehalten. Eine Hypothese ist eine vorläufige Erklärung oder Vorhersage und muss test-, falsifizierbar, präzise und relevant sein. Es gibt verschiedene Randomisierungsarten. Die randomisierte kontrollierte Studie ist der Goldstandard klinischer Interventionsstudien. Beim Lesen einer wissenschaftlichen Arbeit sollte kontrolliert werden, ob Forschungsdesign und -setting zur Forschungsfrage passen, und ob Fehlerquellen bedacht und kontrolliert wurden. Kritisch prüfen lassen sich auch Literaturangaben, Finanzierung und Expertise der Forschenden.
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  • 文章类型: Journal Article
    在受控II期试验中,主要的预后因素需要很好的平衡。使用的主要程序是SPBR(分层置换块随机化)和最小化。首先,我们对2019年发表的胃肠道肿瘤对照II期试验中使用的治疗分配程序进行了系统评价.第二,我们使用6项II期研究的数据进行了模拟,以衡量失衡和偏倚对疗效估计的影响.从分析的40篇文章中,在标题和摘要中都提到了随机化,纳入患者的中位数为109例,77.5%为多中心.在报告至少一个分层变量的27项研究中,10将中心作为分层变量,10个使用的最小化,9二手SBR,和8个未指定。在真实的数据研究中,不平衡随着中心数量的增加而增加。SBR的总失衡和边际失衡高于最小化,差异随着中心数量的增加而增加。在这两个程序中,每个手臂的效率估计都接近原始试验估计。在许多中心的情况下,经常使用最小化,并确保在II期试验中分层变量之间的相似性更好,以实现总体和边际不平衡。
    In controlled phase II trials, major prognostic factors need to be well balanced between arms. The main procedures used are SPBR (Stratified Permuted Block Randomization) and minimization. First, we provide a systematic review of the treatment allocation procedure used in gastrointestinal oncology controlled phase II trials published in 2019. Second, we performed simulations using data from six phase II studies to measure the impacts of imbalances and bias on the efficacy estimations. From the 40 articles analyzed, all mentioned randomization in both the title and abstract, the median number of patients included was 109, and 77.5% were multicenter. Of the 27 studies that reported at least one stratification variable, 10 included the center as a stratification variable, 10 used minimization, 9 used SBR, and 8 were unspecified. In real data studies, the imbalance increased with the number of centers. The total and marginal imbalances were higher with SBR than with minimization, and the difference increased with the number of centers. The efficiency estimates per arm were close to the original trial estimate in both procedures. Minimization is often used in cases of numerous centers and guarantees better similarity between arms for stratification variables for total and marginal imbalances in phase II trials.
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  • 文章类型: Journal Article
    随着下一代测序数据量的增加,迫切需要算法来有效地处理数据。通用命中集(UHS)最近被引入,作为序列分析中最小化器中心思想的替代方案,希望它们能够更有效地解决常见任务,例如计算读取重叠的哈希函数。稀疏后缀数组,和Bloom过滤器。UHS是一组k-mer,它们命中每个长度为L的序列,因此可以用作L长序列的索引。不幸的是,计算小型UHS的方法对于现实世界的测序实例来说还不实用,因为它们具有串行和确定性,当处理k的典型值(例如k>13)时,这导致长运行时间和高存储器需求。为了解决这个瓶颈,我们提出了两种算法创新来显着降低运行时间,同时保持较低的内存使用:(i)我们利用先进的理论和架构技术来并行化并减少计算k-mer命中数的内存使用;(ii)我们基于随机集合覆盖的技术来更快地选择通用k-mer。我们在PASHA中实施了这些创新,用于生成近最优UHS的第一个随机并行算法,新处理k>13。我们凭经验证明,PASHA产生的集合仅比串行确定性算法的集合稍大;此外,可以证明的是,设置的大小保证在最佳大小的一个小的常数因子内。PASHA的运行时间和内存使用改进比当前最佳算法快几个数量级。我们希望在许多高通量序列分析管道中采用我们新实用的UHS结构。
    As the volume of next generation sequencing data increases, an urgent need for algorithms to efficiently process the data arises. Universal hitting sets (UHS) were recently introduced as an alternative to the central idea of minimizers in sequence analysis with the hopes that they could more efficiently address common tasks such as computing hash functions for read overlap, sparse suffix arrays, and Bloom filters. A UHS is a set of k-mers that hit every sequence of length L, and can thus serve as indices to L-long sequences. Unfortunately, methods for computing small UHSs are not yet practical for real-world sequencing instances due to their serial and deterministic nature, which leads to long runtimes and high memory demands when handling typical values of k (e.g. k>13). To address this bottleneck, we present two algorithmic innovations to significantly decrease runtime while keeping memory usage low: (i) we leverage advanced theoretical and architectural techniques to parallelize and decrease memory usage in calculating k-mer hitting numbers; and (ii) we build upon techniques from randomized Set Cover to select universal k-mers much faster. We implemented these innovations in PASHA, the first randomized parallel algorithm for generating nearoptimal UHSs, which newly handles k>13. We demonstrate empirically that PASHA produces sets only slightly larger than those of serial deterministic algorithms; moreover, the set size is provably guaranteed to be within a small constant factor of the optimal size. PASHA\'s runtime and memory-usage improvements are orders of magnitude faster than the current best algorithms. We expect our newly-practical construction of UHSs to be adopted in many high-throughput sequence analysis pipelines.
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  • 文章类型: Journal Article
    当缺乏良好的初始猜测知识时,搜索粒子的随机初始化是支持部署自然启发的元启发式算法的有力论据。本文分析了随机化类型对算法工作和获得的解决方案的影响。在这项研究中,在搜索粒子进行选择性谐波消除(SHE)的初始化和程序期间,将五种不同类型的随机化应用于加速粒子群优化(APSO)和松鼠搜索算法(SSA)。随机化的类型包括指数,正常,瑞利,制服,和Weibull特征。统计分析表明,随机化的类型确实会影响优化算法的工作和目标函数的最佳值。
    A random initialization of the search particles is a strong argument in favor of the deployment of nature-inspired metaheuristic algorithms when the knowledge of a good initial guess is lacked. This article analyses the impact of the type of randomization on the working of algorithms and the acquired solutions. In this study, five different types of randomizations are applied to the Accelerated Particle Swarm Optimization (APSO) and Squirrel Search Algorithm (SSA) during the initializations and proceedings of the search particles for selective harmonics elimination (SHE). The types of randomizations include exponential, normal, Rayleigh, uniform, and Weibull characteristics. The statistical analysis shows that the type of randomization does impact the working of optimization algorithms and the fittest value of the objective function.
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  • 文章类型: Journal Article
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  • 文章类型: Journal Article
    背景:在COVID-19大流行期间,许多重症监护病房(ICU)停止了研究,将重点放在COVID-19特异性研究上。
    目的:描述在大流行期间预防应激性溃疡的国际随机试验(重新评估ICU中对应激侵蚀的抑制作用[REVISE])的实施,解决注册模式,中心参与,知情同意程序,数据收集,一项COVID特异性亚研究,病人转移,和数据监控。
    方法:REVISE是一项针对机械通气患者的随机试验,比较泮托拉唑40mg静脉注射与安慰剂对临床重要上消化道出血的主要疗效结局和90日死亡率的主要安全性结局.我们记录了2020年3月11日至2022年8月30日的协议实施情况。
    结果:指导委员会没有更改科学方案。从2019年7月9日的首次注册到2020年3月10日(大流行前8个月),在18个中心招募了267名患者。从2020年3月11日至2022年8月30日(此后30个月),41个新中心加入;截至2022年8月30日,59个参与,共纳入2961名患者。在大流行阶段总共1235个月的登记期间,入学人数总计暂停106个月(8.6%)(中位数3个月,四分位数间距2;6)。协议的实施涉及从大流行前的先验同意模式(188,58.8%)到同意继续模式(1615,54.1%,p<0.01)。在一个新的中心,选择退出模式获得批准。知情同意率略有增加(80.7%至85.0%,p=0.05)。电话同意增加(16.6%至68.2%,p<0.001)。激增的能力需要机构内的转移;接收中心尽可能继续执行协议。我们开发了一项嵌套的COVID-19子研究。方法中心继续对试验指标进行中央统计监测。现场监控最初是远程的,然后在限制解除时亲自到场。
    结论:大流行期间的方案实施适应包括同意模式的转变,持续的高同意率,并启动了COVID-19子研究。随着新中心的加入,招聘人数增加,优化了患者转移,并调整了监测方法。
    BACKGROUND: During the COVID-19 pandemic, many intensive care units (ICUs) halted research to focus on COVID-19-specific studies.
    OBJECTIVE: To describe the conduct of an international randomized trial of stress ulcer prophylaxis (Re-Evaluating the Inhibition of Stress Erosions in the ICU [REVISE]) during the pandemic, addressing enrolment patterns, center engagement, informed consent processes, data collection, a COVID-specific substudy, patient transfers, and data monitoring.
    METHODS: REVISE is a randomized trial among mechanically ventilated patients, comparing pantoprazole 40 mg IV to placebo on the primary efficacy outcome of clinically important upper gastrointestinal bleeding and the primary safety outcome of 90-day mortality. We documented protocol implementation status from March 11th 2020-August 30th 2022.
    RESULTS: The Steering Committee did not change the scientific protocol. From the first enrolment on July 9th 2019 to March 10th 2020 (8 months preceding the pandemic), 267 patients were enrolled in 18 centers. From March 11th 2020-August 30th 2022 (30 months thereafter), 41 new centers joined; 59 were participating by August 30th 2022 which enrolled 2961 patients. During a total of 1235 enrolment-months in the pandemic phase, enrolment paused for 106 (8.6%) months in aggregate (median 3 months, interquartile range 2;6). Protocol implementation involved a shift from the a priori consent model pre-pandemic (188, 58.8%) to the consent to continue model (1615, 54.1%, p < 0.01). In one new center, an opt-out model was approved. The informed consent rate increased slightly (80.7% to 85.0%, p = 0.05). Telephone consent encounters increased (16.6% to 68.2%, p < 0.001). Surge capacity necessitated intra-institutional transfers; receiving centers continued protocol implementation whenever possible. We developed a nested COVID-19 substudy. The Methods Centers continued central statistical monitoring of trial metrics. Site monitoring was initially remote, then in-person when restrictions lifted.
    CONCLUSIONS: Protocol implementation adaptations during the pandemic included a shift in the consent model, a sustained high consent rate, and launch of a COVID-19 substudy. Recruitment increased as new centers joined, patient transfers were optimized, and monitoring methods were adapted.
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