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Sample size calculation

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https://www.readbyqxmd.com/read/29346452/body-shape-indices-are-predictors-for-estimating-fat-free-mass-in-male-athletes
#1
Yohei Takai, Miyuki Nakatani, Toru Aoki, Daisuke Komori, Kazuyuki Oyamada, Kensuke Murata, Eiji Fujita, Takuya Akamine, Yoshihisa Urita, Masayoshi Yamamoto, Hiroaki Kanehisa
It is unknown whether body size and body shape parameters can be predictors for estimating whole body fat-free mass (FFM) in male athletes. This study aimed to investigate whether body size and shape variables can be predictors for FFM in male athletes. Using a whole-body dual-energy X-ray absorptiometry scanner, whole body fat mass (FM) and FFM were determined in 132 male athletes and 14 sedentary males. The sample was divided into two groups: validation (N = 98) and cross-validation (N = 48) groups. Body height (BH), body mass (BM), and waist circumference at immediately above the iliac crest (W) were measured...
2018: PloS One
https://www.readbyqxmd.com/read/29346210/significance-errors-power-and-sample-size-the-blocking-and-tackling-of-statistics
#2
Edward J Mascha, Thomas R Vetter
Inferential statistics relies heavily on the central limit theorem and the related law of large numbers. According to the central limit theorem, regardless of the distribution of the source population, a sample estimate of that population will have a normal distribution, but only if the sample is large enough. The related law of large numbers holds that the central limit theorem is valid as random samples become large enough, usually defined as an n ≥ 30. In research-related hypothesis testing, the term "statistically significant" is used to describe when an observed difference or association has met a certain threshold...
February 2018: Anesthesia and Analgesia
https://www.readbyqxmd.com/read/29346126/complete-revascularization-for-patients-with-st-segment-elevation-myocardial-infarction-and-multivessel-coronary-artery-disease-a-meta-analysis-of-randomized-trials
#3
Gani Bajraktari, Haki Jashari, Pranvera Ibrahimi, Fernando Alfonso, Fisnik Jashari, Gjin Ndrepepa, Shpend Elezi, Michael Y Henein
INTRODUCTION: Despite the recent findings in randomized clinical trials (RCTs) with limited sample sizes and the updates in clinical guidelines, the current available data for the complete revascularization (CR) in hemodynamically stable patients with ST-segment elevation myocardial infarction (STEMI) at the time of primary percutaneous coronary intervention (PCI) are still contradictory. AIM: The aim of this meta-analysis of the existing RCTs was to assess the efficacy of the CR versus revascularization of infarct-related artery (IRA) only during primary PCI in patients with STEMI and multivessel disease (MVD)...
January 17, 2018: Coronary Artery Disease
https://www.readbyqxmd.com/read/29346063/linking-data-from-health-surveys-and-electronic-health-records-a-demonstration-project-in-two-chicago-health-center-clinics
#4
Fikirte Wagaw, Catherine A Okoro, Sunkyung Kim, Jessica Park, Fred Rachman
INTRODUCTION: Monitoring and understanding population health requires conducting health-related surveys and surveillance. The objective of our study was to assess whether data from self-administered surveys could be collected electronically from patients in urban, primary-care, safety-net clinics and subsequently linked and compared with the same patients' electronic health records (EHRs). METHODS: Data from self-administered surveys were collected electronically from a convenience sample of 527 patients at 2 Chicago health centers from September through November, 2014...
January 18, 2018: Preventing Chronic Disease
https://www.readbyqxmd.com/read/29345299/the-continuing-misuse-of-null-hypothesis-significance-testing-in-biological-anthropology
#5
EDITORIAL
Richard J Smith
There is over 60 years of discussion in the statistical literature concerning the misuse and limitations of null hypothesis significance tests (NHST). Based on the prevalence of NHST in biological anthropology research, it appears that the discipline generally is unaware of these concerns. The p values used in NHST usually are interpreted incorrectly. A p value indicates the probability of the data given the null hypothesis. It should not be interpreted as the probability that the null hypothesis is true or as evidence for or against any specific alternative to the null hypothesis...
January 18, 2018: American Journal of Physical Anthropology
https://www.readbyqxmd.com/read/29344230/reduced-mir-105-1-levels-are-associated-with-poor-survival-of-patients-with-non-small-cell-lung-cancer
#6
Gaixia Lu, Da Fu, Chengyou Jia, Li Chai, Yang Han, Jin Liu, Tingmiao Wu, Ruting Xie, Zhengyan Chang, Huiqiong Yang, Pei Luo, Zhongwei Lv, Fei Yu, Xiaojun Zhong, Yushui Ma
Altered expression of microRNAs (miRNAs or miRs) contributes to lung carcinogenesis. The present study performed an in silico analysis of differentially expressed miRNAs in different peripheral blood samples from patients with various diseases vs. controls using the Gene Expression Omnibus (GEO) database data, and assessed miR-105-1 expression in 32 normal lung and 142 non-small cell lung cancer (NSCLC) tissue samples using reverse transcription-quantitative polymerase chain reaction. Survival data were calculated using Kaplan-Meier curves and a log-rank test...
December 2017: Oncology Letters
https://www.readbyqxmd.com/read/29340847/comparative-analysis-of-aneurysm-volume-by-different-methods-based-on-angiography-and-computed-tomography-angiography
#7
Víctor Hugo Escobar-de la Garma, Marco Zenteno, Felipe Padilla-Vázquez, Daniel San-Juan, Aurelio Cerón-Morales
Endovascular treatment and prognosis of intracranial aneurysms are based on size and volume, which demand more accurate neuroimaging techniques. Aneurysm volume calculation is important to choose endovascular treatment modalities and packing density calculation. Of all these methods, it remains unknown which one is the most accurate to calculate aneurysm volume. The objective of this study is to compare the accuracy of three angiography-based versus three tomographic-based methods which calculate aneurysm volume...
January 16, 2018: Neurosurgical Review
https://www.readbyqxmd.com/read/29339982/relationships-between-mechanical-variables-in-the-traditional-and-close-grip-bench-press
#8
Robert G Lockie, Samuel J Callaghan, Matthew R Moreno, Fabrice G Risso, Tricia M Liu, Alyssa A Stage, Samantha A Birmingham-Babauta, John J Stokes, Dominic V Giuliano, Adrina Lazar, DeShaun L Davis, Ashley J Orjalo
The study aim was to determine relationships between mechanical variables in the one-repetition maximum (1RM) traditional bench press (TBP) and close-grip bench press (CGBP). Twenty resistance-trained men completed a TBP and CGBP 1RM. The TBP was performed with the preferred grip; the CGBP with a grip width of 95% biacromial distance. A linear position transducer measured: lift distance and duration; work; and peak and mean power, velocity, and force. Paired samples t-tests (p < 0.05) compared the 1RM and mechanical variables for the TBP and CGBP; effect sizes (d) were also calculated...
December 2017: Journal of Human Kinetics
https://www.readbyqxmd.com/read/29339615/adsorption-performance-of-polydopamine-modified-attapulgite-granular-adsorbent-for-methylene-blue
#9
Weisheng Zheng, Hailing Wang, Zhaolian Zhu, Peng Wei
Polydopamine-modified granule organo-attapulgite adsorbent (PDA-GOAT) was facilely prepared via a dip-coating approach. The samples were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Surface area and pore size were calculated from the Brunauer-Emmett-Teller method by N2 adsorption-desorption isotherm. The adsorption behaviour of methylene blue (MB) onto PDA-GOAT was systematically investigated. The experimental data revealed that the adsorption process fitted well with the pseudo-second-order kinetics equation and the adsorption isotherm fitted better with the Langmuir model...
January 2018: Water Science and Technology: a Journal of the International Association on Water Pollution Research
https://www.readbyqxmd.com/read/29335232/smartphone-app-using-mindfulness-meditation-for-women-with-chronic-pelvic-pain-memphis-protocol-for-a-randomized-feasibility-trial
#10
Elizabeth Ball, Sian Newton, Brennan C Kahan, Gordon Forbes, Neil Wright, Clara Cantalapiedra Calvete, Harry A L Gibson, Ewelina Rogozinska, Carol Rivas, Stephanie J C Taylor, Judy Birch, Julie Dodds
BACKGROUND: Female chronic pelvic pain (CPP) is defined as intermittent or constant pelvic or lower abdominal pain occurring in a woman for at least 6 months. Up to a quarter of women are estimated to be affected by CPP worldwide and it is responsible for one fifth of specialist gynecological referrals in the United Kingdom. Psychological interventions are commonly utilized. As waiting times and funding capacity impede access to face-to-face consultations, supported self-management (SSM) has emerged as a viable alternative...
January 15, 2018: JMIR Research Protocols
https://www.readbyqxmd.com/read/29333150/evaluation-of-the-correlation-coefficient-of-polyethylene-glycol-treated-and-direct-prolactin-results-and-comparability-with-different-assay-system-results
#11
Shyamali Pal
The presence of Macro prolactin is a significant cause of elevated prolactin resulting in misdiagnosis in all automated systems. Poly ethylene glycol (PEG) pretreatment is the preventive process but such process includes the probability of loss of a fraction of bioactive prolactin. Surprisingly, PEG treated EQAS & IQAS samples in Cobas e 411 are found out to be correlating with direct results of at least 3 immunoassay systems and treated and untreated Cobas e 411 results are comparable by a correlation coefficient...
December 2017: EJIFCC
https://www.readbyqxmd.com/read/29332696/a-comparison-of-plastic-cable-ties-based-on-physical-chemical-and-stable-isotopic-measurements
#12
Lisa M Nienaber, Sarah L Cresswell, James F Carter, Tony Peter
Plastic cable ties can be utilised in a range of serious criminal activities and a comparison of cable ties, or fragments, may form part of the physical evidence presented to a Court of law. This research assessed the potential value of evidence based on the analysis of plastic cable ties. Twenty packets of black coloured plastic cable ties (nominally 200mm×4.8mm) were purchased in pack sizes ranging from 25 to 100 individual cable ties (Brisbane, Australia, March 2015). Representative samples from each packet were visually examined, compared and tested to determine their physical dimensions, chemical compositions and stable isotopic compositions (δ2H, δ13C and δ15N)...
January 2018: Science & Justice: Journal of the Forensic Science Society
https://www.readbyqxmd.com/read/29332218/effects-of-sleep-hygiene-training-given-to-pregnant-women-with-restless-leg-syndrome-on-their-sleep-quality
#13
Ayşe Sönmez, Yeşim Aksoy Derya
PURPOSE: This research was conducted to determine the effects of sleep hygiene training given to pregnant women with restless leg syndrome on their sleep quality. METHODS: This study was conducted using a quasi-experimental design with pre-test and post-test, and a control group. When the power analysis was made, a sample size with 5% two-sided significance, 95% confidence interval, and 95% ability to represent the population was calculated to have a total of 128 pregnant women...
January 13, 2018: Sleep & Breathing, Schlaf & Atmung
https://www.readbyqxmd.com/read/29328531/thalamic-atrophy-in-ms-an-mri-marker-of-neurodegeneration-throughout-disease
#14
Christina J Azevedo, Steven Y Cen, Sankalpa Khadka, Shuang Liu, John Kornak, Yonggang Shi, Ling Zheng, Stephen L Hauser, Daniel Pelletier
OBJECTIVE: Thalamic volume is a candidate MRI-based marker associated with neurodegeneration to hasten development of neuroprotective treatments. Our objective is to describe the longitudinal evolution of thalamic atrophy in MS and normal aging, and to estimate sample sizes for study design. METHODS: 601 subjects (2632 MRI scans) were analyzed. 520 subjects with relapse-onset MS [CIS(90); RR(392); SP(38)] underwent annual standardized 3T MRI scans for an average of 4...
January 12, 2018: Annals of Neurology
https://www.readbyqxmd.com/read/29324378/impact-evaluation-of-environmental-factors-on-respiratory-function-of-asthma-patients-living-in-urban-territory
#15
Lyudmila V Veremchuk, Konstantinos Tsarouhas, Tatyana I Vitkina, Elena E Mineeva, Tatyana A Gvozdenko, Marina V Antonyuk, Valeri N Rakitskii, Karolina A Sidletskaya, Aristidis M Tsatsakis, Kirill S Golokhvast
BACKGROUND: Environmental pollution, local climatic conditions and their association with the prevalence and exacerbation of asthma are topics of intense current medical investigation. MATERIALS AND METHODS: Air pollution in the area of Vladivostock was estimated both by the index of emission volumes of "air gaseous components" (nitrogen oxide and nitrogen dioxide, formaldehyde, hydrogen sulfide, carbon monoxide) in urban atmosphere and by mass spectrometric analysis of precipitates in snow samples...
January 8, 2018: Environmental Pollution
https://www.readbyqxmd.com/read/29323925/the-responsiveness-of-patient-reported-outcome-tools-in-shoulder-surgery-is-dependent-on-the-underlying-pathological-condition
#16
R Zackary Unger, Jeremy M Burnham, Lee Gammon, Chaitu S Malempati, Cale A Jacobs, Eric C Makhni
BACKGROUND: Given the high number of available patient-reported outcome (PRO) tools for patients undergoing shoulder surgery, comparative information is necessary to determine the most relevant forms to incorporate into clinical practice. PURPOSE: To determine the utilization and responsiveness of common PRO tools in studies involving patients undergoing arthroscopic rotator cuff repair or operative management of glenohumeral instability. STUDY DESIGN: Systematic review...
January 1, 2018: American Journal of Sports Medicine
https://www.readbyqxmd.com/read/29322632/approaches-to-sample-size-calculation-for-clinical-trials-in-rare-diseases
#17
Frank Miller, Sarah Zohar, Nigel Stallard, Jason Madan, Martin Posch, Siew Wan Hee, Michael Pearce, Mårten Vågerö, Simon Day
We discuss 3 alternative approaches to sample size calculation: traditional sample size calculation based on power to show a statistically significant effect, sample size calculation based on assurance, and sample size based on a decision-theoretic approach. These approaches are compared head-to-head for clinical trial situations in rare diseases. Specifically, we consider 3 case studies of rare diseases (Lyell disease, adult-onset Still disease, and cystic fibrosis) with the aim to plan the sample size for an upcoming clinical trial...
January 10, 2018: Pharmaceutical Statistics
https://www.readbyqxmd.com/read/29321336/neuroimaging-identifies-patients-most-likely-to-respond-to-a-restorative-stroke-therapy
#18
Jessica M Cassidy, George Tran, Erin B Quinlan, Steven C Cramer
BACKGROUND AND PURPOSE: Patient heterogeneity reduces statistical power in clinical trials of restorative therapies. Valid predictors of treatment responsiveness are needed, and several have been studied with a focus on corticospinal tract (CST) injury. We studied performance of 4 such measures for predicting behavioral gains in response to motor training therapy. METHODS: Patients with subacute-chronic hemiparetic stroke (n=47) received standardized arm motor therapy, and change in arm Fugl-Meyer score was calculated from baseline to 1 month post-therapy...
January 10, 2018: Stroke; a Journal of Cerebral Circulation
https://www.readbyqxmd.com/read/29321002/comparison-of-nuisance-parameters-in-pediatric-versus-adult-randomized-trials-a-meta-epidemiologic-empirical-evaluation
#19
Ben Vandermeer, Ingeborg van der Tweel, Marijke C Jansen-van der Weide, Stephanie S Weinreich, Despina G Contopoulos-Ioannidis, Dirk Bassler, Ricardo M Fernandes, Lisa Askie, Haroon Saloojee, Paola Baiardi, Susan S Ellenberg, Johanna H van der Lee
BACKGROUND: We wished to compare the nuisance parameters of pediatric vs. adult randomized-trials (RCTs) and determine if the latter can be used in sample size computations of the former. METHODS: In this meta-epidemiologic empirical evaluation we examined meta-analyses from the Cochrane Database of Systematic-Reviews, with at least one pediatric-RCT and at least one adult-RCT. Within each meta-analysis of binary efficacy-outcomes, we calculated the pooled-control-group event-rate (CER) across separately all pediatric and adult-trials, using random-effect models and subsequently calculated the control-group event-rate risk-ratio (CER-RR) of the pooled-pediatric-CERs vs...
January 10, 2018: BMC Medical Research Methodology
https://www.readbyqxmd.com/read/29320374/plasmonic-and-sers-performances-of-compound-nanohole-arrays-fabricated-by-shadow-sphere-lithography
#20
Connor Skehan, Bin Ai, Steven R Larson, Keenan M Stone, William Dennis, Yiping Zhao
Several plasmonic compound nanohole arrays (CNAs), such as triangular nanoholes and fan-like nanoholes with multiple nanotips and nanogaps, are designed by a simple and efficient shadow sphere lithography (SSL) technique by tuning the sphere mask size, the deposition and azimuthal angles, substrate temperature TS, and the number of deposition steps N. Compared with conventional circular nanohole arrays (CCNAs), the CNAs show more hot spots and exhibit new transmission speaks. Systematic FDTD calculations indicate that different resonance modes excited by the various shaped and sized nanoholes are responsible for the enhanced plasmonic performances of CNAs...
January 10, 2018: Nanotechnology
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