Podcasts about mann whitney u

Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Predictive Performance on Metaculus vs. Manifold Markets, published by nikos on March 3, 2023 on The Effective Altruism Forum. TLDR I analysed a set of 64 (non-randomly selected) binary forecasting questions that exist both on Metaculus and on Manifold Markets. The mean Brier score was 0.084 for Metaculus and 0.107 for Manifold. This difference was significant using a paired test. Metaculus was ahead of Manifold on 75% of the questions (48 out of 64). Metaculus, on average had a much higher number of forecasters All code used for this analysis can be found here. Conflict of interest noteI am an employee of Metaculus. I think this didn't influence my analysis, but then of course I'd think that and there may be things I haven't thought about. Introduction Everyone likes forecasts, especially if they are accurate (well, there may be some exceptions). As a forecast consumer the central question is: where should you go to get your best forecasts? If there are two competing forecasts that slightly disagree, which one should you trust most? There are a multitude of websites that collect predictions from users and provide aggregate forecasts to the public. Unfortunately, comparing different platforms is difficult. Usually, questions are not completely identical across sites which makes it difficult and cumbersome to compare them fairly. Luckily, we have at least some data to compare two platforms, Metaculus and Manifold Markets. Some time ago, David Glidden created a bot on Manifold Markets, the MetaculusBot, which copied some of the questions on the prediction platform Metaculus to Manifold Markets. Methods Manifold has a few markets that were copied from Metaculus through MetaculusBot. I downloaded these using the Manifold API and filtered for resolved binary questions. There are likely more corresponding questions/markets, but I've skipped these as I didn't find an easy way to match corresponding markets/questions automatically. I merged the Manifold markets with forecasts on corresponding Metaculus questions. I restricted the analysis to the same time frame to avoid issues caused by a question opening earlier or remaining open longer on one of the two platforms. I compared the Manifold forecasts with the community prediction on Metaculus and calculated a time-averaged Brier Score to score forecasts over time. That means, forecasts were evaluated using the following score: S(p,t,y)=∫Tt0(pt−y)2dt, with resolution y and forecast pt at time t. I also did the same for log scores, but will focus on Brier scores for simplicity. I tested for a statistically significant tendency towards higher / lower scores on one platform compared to the other using a paired Mann-Whitney U test. (A paired t-test and a bootstrap analysis yield the same result.) I visualised results using a bootstrap analysis. For that, I iteratively (100k times) drew 64 samples with replacement from the existing questions and calculated a mean score for Manifold and Metaculus based on the bootstrapped questions, as well as a difference for the mean. The precise algorithm is: draw 64 questions with replacement from all questions compute an overall Brier score for Metaculus and one for Manifold take the difference between the two repeat 100k times Results The time-averaged Brier score on the questions I analysed was 0.084 for Metaculus and 0.107 for Manifold. The difference in means was significantly different from zero using various tests (paired Mann-Whitney-U-test: p-value < 0.00001, paired t-test: p-value = 0.000132, bootstrap test: all 100k samples showed a mean difference > 0). Results for the log score look basically the same (log scores were 0.274 for Metaculus and 0.343 for Manifold, differences similarly significant). Here is a plot with the observed differences in time-averaged Brier scores for every qu...

今回はスプレッドシートでマン・ホイットニーのU検定を実装して，非エンジニアでも検定を行えるにしたという内容です． ライブラリは簡単に使える一方で，どういった計算で導出されているかなどを理解して使わないと正しい答えが得られないので，より理解を深めるためにも，今回のようにスプレッドシートで1から自分で計算してみるとよかったです． 参考：スプレッドシートで行うMann-WhitneyのU検定 episode note: 第22回（2021/11/29）: スプレッドシートでマン・ホイットニーのU検定を実装した話 ----------- このPodcastは@navitacion と @asteriam_fp の2人の機械学習エンジニアが気になる話題・興味のあるトピックをお届けするPodcastです． ご意見・ご感想・お便り・ご質問は Twitter DM(@double_m2ml)，からお待ちしております． Keywords: 機械学習/データサイエンス/統計学/Kaggle/MLOps/行動経済学/キャリア...etc

In a preliminary study of the Stability of the mandibular dental arch following periodontally accelerated osteogenic orthodontics therapy (PAOO), it concluded that PAOO therapy resulted in significantly greater improvements during the orthodontic retention period, as judged using the ABO-Objective Grading System on study casts and panoramic radiographs. The study scored for 8 criteria  immediately after orthodontic treatment and at least 1 year of retention.Measuring ResultsThe ABO Objective Grading System for scoring dental casts and panoramic radiographs contains eight criteria: • alignment• marginal ridges• buccolingual inclination or the the angle between the long axis of lower second molars and a reference line tangent to the lower border of the mandibular body• occlusal relationships and contacts related to the grinding or biting surface of a tooth• overjet, or when the upper front teeth protrude outward• interproximal contacts, or the space that lies between teeth that is occupied by the gum, and•root angulation, or the portion of the tooth that is buried in the tissues.PAOO FindingsIn the study, non-extraction orthodontic patients were treated to resolve crowding with PAOO and without PAOO during an average of 19.6 and 16.4 months, respectively.Moreover, the amount of relapse following treatment was significantly greater in both control subgroups compared to both periodontally accelerated osteogenic orthodontics subgroups.A Mann–Whitney U test (used to compare whether there is a difference in the dependent variable for two independent groups) showed that the two groups were statistically homogeneous at post-treatment but at retention, the PAOO group was significantly better for alignment. Moreover, the Objective Grading System total score dropped precipitously (or improved) during retention in the PAOO group compared to the control group. Preliminary retrospective university research indicates that the mandibular dental arch is more stable after PAOO therapy in comparison to traditional orthodontics.It is surmised that the remarkable stability following PAOO is due to substantial “memory” loss of periodontal tissues and increased cortical bone thickness due to alveolar augmentation grafting.About Periodontally accelerated osteogenic orthodonticsPeriodontally accelerated osteogenic orthodontics is a relatively new procedure designed to minimize the time taken for orthodontic treatment. The orthodontist avails of the aid of a periodontist to perform decortication of the bone and places bone graft for rapid orthodontic correction of malocclusion.To discover the latest innovations in orthodontic treatments that reduce treatment times and produce long-lasting, airway-beneficial and aesthetically-superior results schedule a consultation at Airway and Sleep Group.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.01.321828v1?rss=1 Authors: Ekvall, M., Höhle, M., Käll, L. Abstract: Motivation: Permutation tests offer a straight forward framework to assess the significance of differences in sample statistics. A significant advantage of permutation tests are the relatively few assumptions about the distribution of the test statistic are needed, as they rely on the assumption of exchangeability of the group labels. They have great value, as they allow a sensitivity analysis to determine the extent to which the assumed broad sample distribution of the test statistic applies. However, in this situation, permutation tests are rarely applied because the running time of naive implementations is too slow and grows exponentially with the sample size. Nevertheless, continued development in the 1980s introduced dynamic programming algorithms that compute exact permutation tests in polynomial time. Albeit this significant running time reduction, the exact test has not yet become one of the predominant statistical tests for medium sample size. Here, we propose a computational parallelization of one such dynamic programming-based permutation test, the Green algorithm, which makes the permutation test more attractive. Results: Parallelization of the Green algorithm was found possible by nontrivial rearrangement of the structure of the algorithm. A speed-up - by orders of magnitude - is achievable by executing the parallelized algorithm on a GPU. We demonstrate that the execution time essentially becomes a non-issue for sample sizes, even as high as hundreds of samples. This improvement makes our method an attractive alternative to, e.g., the widely used asymptotic Mann-Whitney U-test. Availability: In Python 3 code from the GitHub repository https://github.com/statisticalbiotechnology/parallelPermutationTest under an Apache 2.0 license. Copy rights belong to original authors. Visit the link for more info

Ziel der vorliegenden Studie ist es, den Einfluss von 17β-Östradiol und/oder Progesteron auf die neurologische Funktion in vivo sowie auf die neuronale Morphologie und auf molekulare Aspekte der zerebralen Inflammation und Exzitotoxizität in vitro im Zeitraum von 4 Tagen nach herzchirurgisch typischer extrakorporaler Zirkulation (EKZ) mit 45 min tief hypothermem Kreislaufstillstand („deep hypothermic circulatory arrest“, DHCA) in einem Versuchsmodell an der Ratte zu untersuchen. 100 weibliche Sprague-Dawley-Ratten wurden in 5 Versuchsgruppen (n = 20) randomisiert: Eine Gruppe wurde scheinkastriert (Gruppe „Intakt“); die 4 weiteren Gruppen wurden kastriert und je nach Gruppenzugehörigkeit mit einem subkutanen Hormonimplantat versehen: Plazebo (Gruppe „Plazebo“), 17β-Östradiol (Gruppe „Östrogen“), Progesteron (Gruppe „Progesteron“) sowie 17β-Östradiol- und Progesteron (Gruppe „Progesteron + Östrogen“, „P+Ö“). 4 Wochen nach Kastration/Scheinkastration und gegebenenfalls nach Hormon-/Plazebo-Supplementierung wurden die Tiere mit Isofluran (2,0 – 2,5 Vol% in 40 % O2) anästhesiert, intubiert, katheterisiert, mithilfe der EKZ über 30 min auf 16 °C rektale Körpertemperatur abgekühlt und der DHCA wurde für einen Zeitraum von 45 min durchgeführt. Anschließend wurden die Tiere mittels EKZ über 40 min auf 35,5 °C rektale Körpertemperatur wiedererwärmt, die EKZ beendet, die Tiere 1 Stunde nachbeatmet und eine Telemetrie-Transmittersonde intraperitoneal eingesetzt, bevor die Anästhesie beendet, und die Tiere bei Einsetzen der Spontanatmung extubiert wurden. Die postoperative telemetrische Überwachung umfasste Körpertemperatur und Herzfrequenz, letztere gekoppelt mit einem Alarmsystem, um Tiere bei Bedarf (Herzfrequenz < 150 Schläge/min) rechtzeitig euthanasieren zu können. Alle Tiere wurden am präoperativen Tag 1 (Tag –1) neurologisch untersucht sowie an den postoperativen Tagen 1, 2, 3 und 4, sofern sie überlebt haben. Am postoperativen Tag 4 wurden die Tiere in tiefer Isoflurannarkose zur Blut- und Serum-Gewinnung entblutet sowie deren Gehirne entnommen und tiefgefroren (–80 °C). In Hämatoxylin-Eosin (HE-) gefärbten Gehirnschnitten wurde die Anzahl intakter und geschädigter Neurone lichtmikroskopisch in den Bereichen Striatum (Bregma –0,3 mm), Kortex und Hippokampus (Bregma –3,3 mm) ermittelt. Die TNFα-Konzentration im Serum der Tiere wurde mittels Enzyme-linked Immunosorbent Assay bestimmt. Die zerebrale Expression von Östrogenrezeptor α (ERα), von Östrogenrezeptor β (ERβ), von „Excitatory Amino Acid Transporter 1“ (EAAT1), von „Glutamat Transporter 1b“ (GLT-1b), von „CXC-Motiv-Chemokinrezeptor 2“, (CXCR2), von Interleukin-8 (IL-8) und von induzierbarer Stickoxid Synthase (iNOS) erfolgte mit dem Western-Blot-Verfahren. Die durchgeführten Auswertungen erfolgten für eine nach spezifischen Kriterien getroffene Auswahl von jeweils 5 überlebenden Tieren und 5 euthanasierten Tieren pro Versuchsgruppe. Die statistische Datenanalyse wurde mithilfe allgemeiner linearer Modelle mit post-hoc einfaktorieller Varianzanalyse und Bonferroni-t-Tests bzw. Kruskal-Wallis und post-hoc Mann-Whitney U (p < 0,05) durchgeführt. Die Ergebnisse zeigen keine Versuchsgruppen-spezifischen Unterschiede bei den intra- und postoperativen physiologischen Parametern. Die Serumkonzentrationen von TNFα, die Gehirnmorphologie und die neurologische Funktion zeigten sich vom Versuchsansatz unbeeinflusst. Beim Nachweis der Expression von Rezeptor-, Transporter- und Entzündungsproteinen im Gehirngewebe mittels Western-Blot-Verfahren zeigten sich bei einigen Proteinen Versuchsgruppen-spezifische Unterschiede: Die vorzeitig euthanasierten Tiere der Gruppe „Plazebo“ zeigten eine niedrigere Expression von ERβ als die überlebenden Tiere dieser Gruppe und als die ebenfalls vorzeitig euthanasierten Gruppen „Östrogen“ und „P+Ö“. Des Weiteren exprimierten die überlebenden Tiere der Gruppe „P+Ö“ signifikant mehr EAAT1 im Gehirn als die vorzeitig euthanasierten Tiere dieser Gruppe und auch als die überlebenden Tiere der „Plazebo“-Gruppe. Zusätzlich zeigte sich, dass physiologische hormonelle Schwankungen im Rahmen des Zyklusgeschehens bei der gemeinsamen Wirkung von 17β-Östradiol und Progesteron (Gruppe „Intakt“) im Rahmen der postoperativen zerebralen Inflammation sowohl vorteilhaft (reduzierte iNOS-Expression) als auch von Nachteil (erhöhte IL-8-Expression) gegenüber einer Substituion dieser beiden Hormone (Gruppe „P+Ö“) sein können. Zusammenfassend gesehen bieten aus der Vielzahl der untersuchten Parameter und Faktoren insbesondere die für die zerebrale Inflammation und Exzitotoxizität typischen spezifischen Proteine ausreichend Potential für weiterführende, tierexperimentell ähnlich gestaltete Untersuchungen. Langfristig könnten hier zusätzliche Tierversuchsmodelle wie z. B. Alterung, Diabetes, Atherosklerose und Hypertension eine weitere Annäherung an humanklinische Verhältnisse ermöglichen.

The purpose of this study was: (1) to assess the cephalometric variables of the nasopharynx, oropharynx and laryngopharynx including soft palate among male and female subjects with different anteroposterior jaw relationships, orthognathic and retrognathic, treated with a rapid maxillary expander, a Hyrax-Type expansion appliance, in two dimensions; (2) to assess the cephalometric variables of the pharyngeal area in the control group; (3) to compare the variables of both groups in order to investigate the pharyngeal area. Seventy-one maxillary constriction subjects, 39 females and 32 males, were selected from the records section of the Department of Orthodontics of the Ludwig Maximilian University, Munich, on the basis of the following criteria: (1) patient with skeletal maxillary constriction; (2) no observable craniofacial abnormalities; (3) no previous orthodontic treatment; (4) first permanent molars, primary molars or premolars were in occlusion; and (5) each lateral cephalometric radiograph was taken with teeth in centric occlusion. The RME group was compared with a control group comprising 47 samples with normal transversal maxilla. The average age of the control group at the first observation was 9.94 + 2.11 years and RME group before treatment was 10.15 + 2.22 years. In 71 patients, orthodontic treatment was started with RME, followed by conventional orthodontic treatment, not combined with any other form of orthodontic device. Twelve linear measurements, including pharyngeal airway and soft palate dimensions were determined. The lateral cephalometric radiographs were taken at the first examination for pretreatment and annual follow up for post-treatment was undertaken. All cephalometric radiographs were hand-traced by one investigator using 0.35 mm lead 2H pencil on 0.003 mm matte acetate tracing paper in a darkened room with extraneous light from the viewing box. All tracings were measured with a digital caliper. The differences between the RME and the control group were compared. The pharyngeal area and soft palate changed following RME treatment in the RME group and with growth in the control group. In the RME treatment group, there were statistically significant differences between the facial type of males and sex-related differences in orthognathic patients. No statistically significant differences were found between subgroups of the control patients and between the RME and control groups with the Mann Whitney U-test (P < 0.05). The results suggest that airway dimension and soft palate underwent noticeable changes after treatment with RME whereas the control group changed after growth factor event and changing environment. These changes are usually produced and may be compensated in time by natural growth. Thus RME has been shown to be capable of assisting nature in the natural process of growth. Finally, all patients considered for RME should be examined for nasal obstruction and if obstruction is found, prior to commencing orthodontic treatment, they should be referred to an otolaryngologist for examination and treatment of the problem.

Background: There is evidence that homocysteine contributes to various neurodegenerative disorders. Objective: To assess the values of homocysteine in patients with Creutzfeldt-Jakob disease (CJD) in both cerebrospinal fluid (CSF) and plasma. Methods: Study design: Case control study. Total homocysteine was quantified in CSF and plasma samples of CJD patients (n = 13) and healthy controls (n = 13). Results: Mean values in healthy controls: 0.15 mumol/l +/- 0.07 (CSF) and 9.10 mumol/l +/- 2.99 (plasma); mean values in CJD patients: 0.13 mumol/l +/- 0.03 (CSF) and 9.22 mumol/l +/- 1.81 (plasma). No significant differences between CJD patients and controls were observed (Mann-Whitney U, p > 0.05). Conclusions: The results indicate that the CSF and plasma of CJD patients showed no higher endogenous levels of homocysteine as compared to normal healthy controls. These findings provide no evidence for an additional role of homocysteine in the pathogenetic mechanisms underlying CJD neurodegeneration. Copyright (C) 2005 S. Karger AG, Basel.

Das Ziel dieser In-vitro-Untersuchung war es die Randqualität von lichthärtenden kompositbasierten Füllungsmaterialien in Klasse-II-MOD Füllungen im approximalem Bereich zu überprüfen. In 80 extrahierten, menschlichen Molaren wurden standardisierte MOD-Inlay- Kavitäten präpariert. Bei einer approximalen Extension lag der zervikale Präparationsrand 1mm koronal der Schmelz-Zement-Grenze (SZG) und bei der anderen approximalen Extension 1mm apikal der SZG. Die Probenzähne wurden randomisiert in 10 Gruppen verteilt. In den Gruppen APB842, AKJ842, BPB842, BKJ842 wurde die präparierte Zahnoberfläche im Sinne der Total-etch-Technik vorbehandelt und anschließend wurde ein azetonbasierter Einkomponentenhaftvermittler (Prime & Bond NT oder KJ7-101-07) appliziert. Nach der Polymerisation erfolgte das Erstellen der Restaurationen aus ormocerbasierten Kompositmaterialien (experimentelles Material A und B) mittels konventioneller Verarbeitungstechnik. In den Gruppen QX812, QX814, QX524 und QFX814 wurde ein selbstkonditionierender Haftvermittler (XenoIII) auf die präparierte Zahnoberfläche aufgetragen. Der Lichtpolymerisation des Haftvermittlers folgte das Anfertigen der Restaurationen aus dem Material Quixfil. Das konventionelle Verarbeitungskonzept wurde nach den Angaben des Herstellers modifiziert. Die Polymerisationszeit wurde verkürzt und in den Gruppen QX814, QX524 und QFX814 wurde im dentinbegrenztem Kasten eine 4 mm Schicht appliziert. In der Gruppe QFX814 wurde ein Liner aus fließfähigem Komposit benutzt. Als Referenzgruppen wurden Restaurationen aus Material Tetric Ceram mit Syntac classic (TSC842) und aus Material Surefil mit Prime&Bond NT (SPB844) herangezogen. Nach dem Ausarbeiten und Politur der angefertigten Restaurationen wurden die Proben einer künstlichen Alterung unterzogen (Thermowechselbad 5/55°C, 2000 Zyklen, Kausimulator – okklusale Belastung 50 N, 50 000 Zyklen). Bei der morphologischen Untersuchung wurden Epoxyharzreplika von beiden approximalen Seiten einer quantitativen Randspaltanalyse im Rasterelektronenmikroskop bei 200-facher Vergrößerung unterzogen. Bei dem Farbpenetrationstest wurden die Probenzähne in Methylenblaulösung eingetaucht (5%, 15 Min.), geschnitten und auf die Tiefe der Farbpenetration untersucht. Statistische Analyse der Ergebnisse (Kruskal-Wallis H-test, Mann-Whitney U-test) zeigte signifikante Unterschiede zwischen den untersuchten Gruppen. Der adhäsive Verbund zwischen Komposit und Dentin war anfälliger für das Auftreten von Randspalten als der Verbund zum Zahnschmelz. Im Dentin variierte der prozentuale Anteil an perfektem Rand zwischen 87,9% (BKJ842) und 56,9% (SPB842), im Schmelz zwischen 97,2% (TSC842) und 77,4% (SPB842). In der Gruppe BKJ842 konnte teilweise signifikant bessere Randqualität erreicht werden als in der Gruppe BPB842. Die Ergebnisse der Gruppen APB842, AKJ842, BPB842, BKJ842 waren mit der Referenzgruppe TCS842 vergleichbar. In den Gruppen QX812, QX814, QX524 und QFX814 hat sich das variieren der Lichtpolymerisation und der Schichtstärke auf die Qualität der marginalen Adaptation nicht signifikant ausgewirkt. Mit einem Liner aus fließfähigem Komposit wurde die Randdichtigkeit dentinbegrenzter Füllungsränder erhöht. Die Randqualität der Restaurationen aus Material Quixfil war vor allem in der Randdichtigkeit (außer QFX814) mit der Referenzgruppe SPB844 vergleichbar.

Background: Lymphocytes are recruited to sites of inflammation by chemokines. Accordingly, a number of chemokine receptors are differentially expressed on effector T cells. We hypothesized that selected T cells accumulate in inflammatory lung diseases involving different pulmonary compartments. To test this hypothesis the frequencies of chemokine receptor expressing T cells were compared in peripheral blood (PB) and bronchoalveolar lavage fluid (BALF) of children with chronic bronchitis and interstitial lung diseases. Methods: BAL was performed in 70 children. According to clinical, macroscopic and cytological findings 37 children were selected for the study and classified as chronic bronchitis (CB, n=17, m=7, mean age 6.6 yrs.) or interstitial lung diseases (ILD, n=20, m=13, mean age 7.0 yrs.). Patients (n=33) with other diagnoses or without cells in BALF were excluded. CD4+ and CD8+ T cells were analyzed in PB (n=30) and BALF (n=37) by flow cytometry. The percentages of CCR5+and CXCR3+ cells were determined within each T cell subset. Results are expressed as medians. For statistical analyses non-parametric tests (Wilcoxon, Mann-Whitney U) were applied. Results: In peripheral blood, the percentage of CXCR3+ T cells (16.4%, range: 0-35.2%) was higher than the percentage of CCR5+ T cells (3.9%, range: 0-19.1%; p

Background: The multifocal pattern electroretinogram (mfPERG) allows analysis of local ganglion cell dysfunction by multifocal stimulation. Aim of this study was to investigate if this method is an useful tool for diagnosing and following glaucoma patients. Methods: Measurements on 52 age-matched normal eyes were compared to those on 23 eyes with different stages of glaucoma. A RETIScan system was used to generate a stimulus pattern of 19 hexagons, each consisting of 6 triangles. The triangles pattern-reversed black to white at 75 Hz. Those 19 hexagons form 3 stimulus regions: a central field, a middle and a peripheral ring. The complete array subtended 48° at the eye. The hexagons alternated black-white following a corrected binary m-sequence (length 512, 10 cycles with 39 second each). Corneal loop electrodes were used with reference electrode on temple. Results: The mfPERGs were analyzed for significant changes in amplitude and latency of the positive and negative responses. For patients with glaucoma the positive P-50 and negative N-95 components were significantly reduced for the central area and both rings compared to normal volunteers (p

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.17.046466v1?rss=1 Authors: Chelebian, E., Fuster-Garcia, E., Alvarez-Torres, M. d. M., Juan-Albarracin, J., Garcia-Gomez, J. M. Abstract: BACKGROUND AND PURPOSE: Genetic classifications are crucial for understanding the heterogeneity of glioblastoma. Recently, MR perfusion imaging techniques have demonstrated their ability to determine molecular alterations. In this work, we investigated whether perfusion markers within infiltrated peripheral edema were associated with proneural, mesenchymal, classical and neural subtypes. MATERIALS AND METHODS: ONCOhabitats open web service was used to obtain the cerebral blood volume at the infiltrated peripheral edema for MRI studies of 50 glioblastoma patients from The Cancer Imaging Archive: TCGA-GBM. ANOVA and Kruskal-Wallis tests were carried out in order to assess the association between vascular features and the subtypes. For assessing specific differences, Mann-Whitney U-test was conducted. Finally, the association of overall survival with molecular and vascular features was assessed using univariate and multivariate Cox models. RESULTS: ANOVA and Kruskal-Wallis tests for the maximum cerebral blood volume at the infiltrated peripheral edema between the four subclasses yielded false discovery rate corrected p-values of