keyword
MENU ▼
Read by QxMD icon Read
search

Sample size calculation

keyword
https://www.readbyqxmd.com/read/29150339/hair-concentration-of-trace-elements-and-growth-in-homeless-children-aged-6years-results-from-the-enfams-study
#1
Lucia Fábelová, Stéphanie Vandentorren, Cécile Vuillermoz, Robert Garnier, Sandrine Lioret, Jérémie Botton
BACKGROUND: Growth is an important indicator of health in early childhood. This is a critical developmental period, during which a number of factors, including exposure to metals, might play a role in later physical and metabolic functions. OBJECTIVE: To study the association between exposure to arsenic (As), cadmium (Cd), mercury (Hg), lead (Pb) and selenium (Se), and physical growth of children from homeless families aged <6years. METHODS: This study was based on data of the cross-sectional survey (ENFAMS), which was conducted by the Observatoire du Samu Social on a random sample of homeless sheltered families in the Paris region during winter 2013...
November 14, 2017: Environment International
https://www.readbyqxmd.com/read/29150186/articular-scaling-and-body-mass-estimation-in-platyrrhines-and-catarrhines-modern-variation-and-application-to-fossil-anthropoids
#2
Jonathan M G Perry, Siobhán B Cooke, Jacqueline A Runestad Connour, M Loring Burgess, Christopher B Ruff
Body mass is an important component of any paleobiological reconstruction. Reliable skeletal dimensions for making estimates are desirable but extant primate reference samples with known body masses are rare. We estimated body mass in a sample of extinct platyrrhines and Fayum anthropoids based on four measurements of the articular surfaces of the humerus and femur. Estimates were based on a large extant reference sample of wild-collected individuals with associated body masses, including previously published and new data from extant platyrrhines, cercopithecoids, and hominoids...
November 14, 2017: Journal of Human Evolution
https://www.readbyqxmd.com/read/29149955/hemodialysis-patients-willingness-to-undergo-kidney-transplantation-an-observational-study
#3
H Alansari, A Almalki, L Sadagah, M Alharthi
BACKGROUND: The number of dialysis patients is increasing, with only 20% undergoing kidney transplantation. In Saudi Arabia, no studies had examined transplantation barriers from the patients' perspectives. We aimed in this study to estimate hemodialysis (HD) patients' willingness to undergo kidney transplantation and to explore its underlying determinants. METHODS: In an observational cross-sectional study involving adult HD patients from King Abdulaziz Medical City and King Abdullah Dialysis Center-Jeddah, patients were interviewed through a pre-tested questionnaire...
November 2017: Transplantation Proceedings
https://www.readbyqxmd.com/read/29149174/cystatin-b-cathepsin-l-and-d-related-to-surrogate-markers-for-cardiovascular-disease-in-children
#4
Magnus Dencker, Tina Tanha, Magnus K Karlsson, Per Wollmer, Lars B Andersen, Ola Thorsson
OBJECTIVE: This study investigated potential associations between novel biomarkers for cardiovascular disease and other surrogate markers for health. METHODS: Community sample of 170 (92 boys and 78 girls) children aged 8-11 years. Total fat mass (TBF) and abdominal fat (AFM) were measured by Dual-energy x-ray absorptiometry (DXA). Total body fat was also expressed as percentage of total body mass (BF%), and body fat distribution was calculated as AFM/TBF. Maximal oxygen uptake (VO2PEAK), systolic and diastolic blood pressure (SBP and DBP) and pulse pressure (PP) were measured...
2017: PloS One
https://www.readbyqxmd.com/read/29147785/qt-interval-and-dispersion-in-drug-free-anorexia-nervosa-adolescents-a-case-control-study
#5
Monica Bomba, Lucio Tremolizzo, Fabiola Corbetta, Franco Nicosia, Francesca Lanfranconi, Gianni Poggioli, Karine Goulene, Marco Stramba-Badiale, Elisa Conti, Francesca Neri, Renata Nacinovich
Long QT values have been reported in patients with anorexia nervosa of the restricting type (ANr) potentially increasing the risk of fatal arrhythmia, especially if psychotropic drug treatment is required. Nevertheless, the previous studies on this topic are biased by drug exposure, long disease durations, and small sample sizes. This study is aimed at assessing QTc and QTcd values in ANr adolescents with recent onset and drug free, as compared to subjects affected by psychiatric disorders other than ANr. We evaluated QTc and its dispersion (QTcd) in a population of 77 drug-free ANr female adolescents and compared to an equal number of healthy controls (H-CTRL) and pathological controls (P-CTRL, mixed psychiatric disorders)...
November 16, 2017: European Child & Adolescent Psychiatry
https://www.readbyqxmd.com/read/29146656/prevalence-of-diabetic-retinopathy-in-children-and-young-people-living-with-diabetes-protocol-for-a-systematic-review
#6
Maria Carolina Ibanez-Bruron, Ameenat L Solebo, Phillippa M Cumberland, Jugnoo S Rahi
INTRODUCTION: The frequency of diabetes mellitus in childhood is increasing. Thus, more children and young people are at risk of developing diabetic retinopathy and diabetes related visual impairment. However, there is no consensus on optimal screening strategies for the paediatric population reflecting the lack of clarity about the current burden of disease in this group. We aim to estimate the prevalence of diabetic retinopathy in children and young people living with types 1 or 2 diabetes, and to investigate potential sources of heterogeneity in this figure so as to inform screening strategies for this population...
November 15, 2017: BMJ Open
https://www.readbyqxmd.com/read/29146637/unequal-cluster-sizes-in-stepped-wedge-cluster-randomised-trials-a-systematic-review
#7
Caroline Kristunas, Tom Morris, Laura Gray
OBJECTIVES: To investigate the extent to which cluster sizes vary in stepped-wedge cluster randomised trials (SW-CRT) and whether any variability is accounted for during the sample size calculation and analysis of these trials. SETTING: Any, not limited to healthcare settings. PARTICIPANTS: Any taking part in an SW-CRT published up to March 2016. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome is the variability in cluster sizes, measured by the coefficient of variation (CV) in cluster size...
November 15, 2017: BMJ Open
https://www.readbyqxmd.com/read/29146283/a-computational-framework-for-estimating-statistical-power-and-planning-hypothesis-driven-experiments-involving-one-dimensional-biomechanical-continua
#8
Todd C Pataky, Mark A Robinson, Jos Vanrenterghem
Statistical power assessment is an important component of hypothesis-driven research but until relatively recently (mid-1990s) no methods were available for assessing power in experiments involving continuum data and in particular those involving one-dimensional (1D) time series. The purpose of this study was to describe how continuum-level power analyses can be used to plan hypothesis-driven biomechanics experiments involving 1D data. In particular, we demonstrate how theory- and pilot-driven 1D effect modeling can be used for sample-size calculations for both single- and multi-subject experiments...
October 7, 2017: Journal of Biomechanics
https://www.readbyqxmd.com/read/29145831/copd-online-rehabilitation-versus-conventional-copd-rehabilitation-rationale-and-design-for-a-multicenter-randomized-controlled-trial-study-protocol-core-trial
#9
Henrik Hansen, Theresa Bieler, Nina Beyer, Nina Godtfredsen, Thomas Kallemose, Anne Frølich
BACKGROUND: Rehabilitation of patients with chronic obstructive pulmonary disease (COPD) is a key treatment in COPD. However, despite the existing evidence and a strong recommendation from lung associations worldwide, 50% of patients with COPD decline to participate in COPD rehabilitation program and 30-50% drop-out before completion. The main reasons are severe symptoms, inflexible accessibility and necessity for transportation. Currently there are no well-established and evident rehabilitation alternatives...
November 16, 2017: BMC Pulmonary Medicine
https://www.readbyqxmd.com/read/29145780/power-and-sample-size-for-multivariate-logistic-modeling-of-unmatched-case-control-studies
#10
Mitchell H Gail, Sebastien Haneuse
Sample size calculations are needed to design and assess the feasibility of case-control studies. Although such calculations are readily available for simple case-control designs and univariate analyses, there is limited theory and software for multivariate unconditional logistic analysis of case-control data. Here we outline the theory needed to detect scalar exposure effects or scalar interactions while controlling for other covariates in logistic regression. Both analytical and simulation methods are presented, together with links to the corresponding software...
January 1, 2017: Statistical Methods in Medical Research
https://www.readbyqxmd.com/read/29145769/exact-statistical-calculation-of-the-uncertainty-term-in-the-decision-limits-of-the-gh-2000-score-for-growth-hormone-misuse-doping-detection
#11
Dankmar Böhning, Wei Liu, Richard Ig Holt, Walailuck Böhning, Nishan Guha, Peter Sönksen, David Cowan, Tianyi Liang
The GH-2000 score has been developed as a powerful and unique technique for the detection of growth hormone misuse by sportsmen and women. The score depends upon the measurement of two growth hormone sensitive markers, insulin-like growth factor-I and the amino-terminal pro-peptide of type III collagen. It also includes a term to adjust for the age of the athlete. Decision limits for the GH-2000 score have been developed and are incorporated into the guidelines of the World Anti-Doping Agency. These decision limits are derived by setting a 1 in 10,000 false-positive rate rule...
January 1, 2017: Statistical Methods in Medical Research
https://www.readbyqxmd.com/read/29143863/morphometric-properties-of-the-latissimus-dorsi-muscle-in-human-fetuses-for-flap-surgery
#12
Orhan Beger, Burhan Beger, Deniz Uzmansel, Semra Erdoğan, Zeliha Kurtoğlu
PURPOSE: Although latissimus dorsi (LD) flaps are extensively used in a wide range of interventions, fetus studies on this subject are quite limited. This study aims to obtain detailed information about the morphometric features of LD, thoracodorsal artery (TDA) and nerve (TDN). METHODS: The study was carried out on both sides of 50 formalin-fixed human fetuses (22 male/28 female) with a mean gestational age of 24.5 ± 4.7 (range 18-36) weeks, which were in the inventory of Anatomy Department of Mersin University Faculty of Medicine...
November 16, 2017: Surgical and Radiologic Anatomy: SRA
https://www.readbyqxmd.com/read/29143253/ruling-out-clinically-significant-prostate-cancer-with-negative-multi-parametric-mri
#13
Julie Y An, Abhinav Sidana, Sarah A Holzman, Joseph A Baiocco, Sherif Mehralivand, Peter L Choyke, Bradford J Wood, Baris Turkbey, Peter A Pinto
PURPOSE: To evaluate the negative predictive value (NPV) of a negative prostate multi-parametric magnetic resonance imaging (mpMRI) in ruling out clinically significant prostate upon 12-core systematic biopsy. METHODS: We retrospectively reviewed 114 men evaluated at our institution who underwent systematic 12-core biopsy within 1 year of a negative prostate mpMRI. Clinicopathologic features were evaluated and NPV was calculated for detection of clinically significant (Gleason ≥ 7) cancer...
November 15, 2017: International Urology and Nephrology
https://www.readbyqxmd.com/read/29142758/ethnic-differences-in-patients-perceptions-towards-isolated-orthopedic-injuries-a-pilot-study
#14
Boris A Zelle, Gurpreet Singh, Deanna L Kitchen, Roberto J Fajardo, Mohit Bhandari, Melissa A Valerio
Background: Patients' perceptions of their healthcare have been reported to influence clinical outcomes following orthopedic trauma. Findings across clinical outcomes have demonstrated significant differences in perceptions towards healthcare between Hispanics and non-Hispanic whites. However, ethnic disparities in perceptions towards orthopedic injuries have not been examined in the literature. Aim of study: The aim of this pilot study is to explore whether Hispanic patients with isolated orthopedic injuries will demonstrate different perceptions towards their injury as compared to non-Hispanic white patients...
2017: Pilot and Feasibility Studies
https://www.readbyqxmd.com/read/29140552/the-influence-of-phylogeny-social-style-and-sociodemographic-factors-on-macaque-social-network-structure
#15
Krishna N Balasubramaniam, Brianne A Beisner, Carol M Berman, Arianna De Marco, Julie Duboscq, Sabina Koirala, Bonaventura Majolo, Andrew J MacIntosh, Richard McFarland, Sandra Molesti, Hideshi Ogawa, Odile Petit, Gabriele Schino, Sebastian Sosa, Cédric Sueur, Bernard Thierry, Frans B M de Waal, Brenda McCowan
Among nonhuman primates, the evolutionary underpinnings of variation in social structure remain debated, with both ancestral relationships and adaptation to current conditions hypothesized to play determining roles. Here we assess whether interspecific variation in higher-order aspects of female macaque (genus: Macaca) dominance and grooming social structure show phylogenetic signals, that is, greater similarity among more closely-related species. We use a social network approach to describe higher-order characteristics of social structure, based on both direct interactions and secondary pathways that connect group members...
November 15, 2017: American Journal of Primatology
https://www.readbyqxmd.com/read/29138444/the-elusive-evidence-of-volcanic-lightning
#16
K Genareau, P Gharghabi, J Gafford, M Mazzola
Lightning strikes are known to morphologically alter and chemically reduce geologic formations and deposits, forming fulgurites. A similar process occurs as the result of volcanic lightning discharge, when airborne volcanic ash is transformed into lightning-induced volcanic spherules (LIVS). Here, we adapt the calculations used in previous studies of lightning-induced damage to infrastructure materials to determine the effects on pseudo-ash samples of simplified composition. Using laboratory high-current impulse experiments, this research shows that within the lightning discharge channel there is an ideal melting zone that represents roughly 10% or less of the total channel radius at which temperatures are sufficient to melt the ash, regardless of peak current...
November 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29137376/impact-of-vegfa-polymorphisms-on-glioma-risk-in-chinese
#17
Peng Zhao, Anjing Chen, Qichao Qi, Wenjing Zhou, Zichao Feng, Jiwei Wang, Ning Yang, Xingang Li, Jian Wang, Qibing Huang, Bin Huang
Several single nucleotide polymorphisms (SNPs) in the vascular endothelial growth factor A (VEGFA) gene have been previously reported to be associated with glioma susceptibility, but individual studies have demonstrated inconclusive results. In the current study, a meta-analysis was performed to derive a more precise estimation of the involvement of VEGFA polymorphisms in glioma development. A comprehensive literature search conducted in PubMed, Embase, the Cochrane Library, and OVID databases through February 25, 2017 yielded 4 eligible studies consisting of 2,275 cases and 2,475 controls...
October 13, 2017: Oncotarget
https://www.readbyqxmd.com/read/29137163/association-between-small-fetuses-and-puberty-timing-a-systematic-review-and-meta-analysis
#18
REVIEW
Xu Deng, Wenyan Li, Yan Luo, Shudan Liu, Yi Wen, Qin Liu
Background: Epidemiological studies reporting the effect of small fetuses (SF) on puberty development have shown inconsistent results. Objective: To examine current study evidence and determine the strength and direction of the association between SF and puberty timing. Methods: PubMed, OVID, Web of Science, EBSCO, and four Chinese databases were searched from their date of inception to February 2016. All cohort studies that examined the association between SF and puberty timing in children were identified...
November 13, 2017: International Journal of Environmental Research and Public Health
https://www.readbyqxmd.com/read/29137042/associations-among-medication-regimen-complexity-medical-specialty-and-medication-possession-ratio-in-newly-diagnosed-hypertensive-patients-a-population-based-study
#19
Chen-Pei Ho, Jih-I Yeh, Shu-Hui Wen, Tony Jer-Fu Lee
The aim of this study was to explore the associations among the medication regimen complexity index (MRCI), medical specialty, and medication possession ratio (MPR) in newly diagnosed hypertensive patients.Data from 19,859 newly diagnosed hypertensive patients were collected from 2,000,000 random samples of the National Health Insurance Research Database in Taiwan. All study participants were followed for 1 year after the first diagnosis of hypertension. MPR was defined as total days of antihypertensive drugs supplied/365 days...
November 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/29136784/the-alternation-of-autophagy-apoptosis-in-cd4-cd25-foxp3-tregs-on-the-developmental-stages-of-atherosclerosis
#20
Yuling Tian, Xiao Liang, Yue Wu
Naturally regulatory T cells (Tregs) play a critical role in the regulation of T cell-mediated immune responses in atherosclerosis. However, the regulatory mechanism underlying Tregs upon long-term development of atherosclerosis remains unknown. Therefore, in this study, atherosclerotic model was induced in ApoE-/- mice by feeding fat-diet for 10 weeks. Quantification of atherosclerotic lesions was done by calculating the lesion size in the aortic sinus every 2 weeks. The lipid levels and inflammatory mediators were detected in serum sample...
November 8, 2017: Biomedicine & Pharmacotherapy, Biomédecine & Pharmacothérapie
keyword
keyword
5489
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"