Read by QxMD icon Read

Composite quantile regression

Alessandra C de Paula Silveira, Sacha B Chaves, Leandro A Hilgert, Ana Paula D Ribeiro
STATEMENT OF PROBLEM: The precision of fit of chairside computer-aided design and computer-aided manufacturing (CAD-CAM) complete crowns is affected by digital impression and restorative material. PURPOSE: The purpose of this in vitro study was to evaluate by microcomputed tomography (μCT) the marginal and internal adaptation of composite resin and ceramic complete crowns fabricated with 2 different intraoral cameras and 2 restorative materials. MATERIAL AND METHODS: Ten extracted human third molars received crown preparations...
September 24, 2016: Journal of Prosthetic Dentistry
Degui Li, Runze Li
In this paper, we study the local polynomial composite quantile regression (CQR) smoothing method for the nonlinear and nonparametric models under the Harris recurrent Markov chain framework. The local polynomial CQR regression method is a robust alternative to the widely-used local polynomial method, and has been well studied in stationary time series. In this paper, we relax the stationarity restriction on the model, and allow that the regressors are generated by a general Harris recurrent Markov process which includes both the stationary (positive recurrent) and nonstationary (null recurrent) cases...
September 2016: Journal of Econometrics
Amit G Singal, Peng Zhang, Akbar K Waljee, Lakshmi Ananthakrishnan, Neehar D Parikh, Pratima Sharma, Pranab Barman, Venkataramu Krishnamurthy, Lu Wang, Stewart C Wang, Grace L Su
OBJECTIVES: Existing prognostic models for patients with hepatocellular carcinoma (HCC) have limitations. Analytic morphomics, a novel process to measure body composition using computational image-processing algorithms, may offer further prognostic information. The aim of this study was to develop and validate a prognostic model for HCC patients using body composition features and objective clinical information. METHODS: Using computed tomography scans from a cohort of HCC patients at the VA Ann Arbor Healthcare System between January 2006 and December 2013, we developed a prognostic model using analytic morphomics and routine clinical data based on multivariate Cox regression and regularization methods...
May 26, 2016: Clinical and Translational Gastroenterology
James P Herrera
Models of ecological community assembly predict how communities of interacting organisms may be shaped by abiotic and biotic factors. Competition and environmental filtering are the predominant factors hypothesized to explain community assembly. This study tested the effects of habitat, phylogenetic and phenotypic trait predictors on species co-occurrence patterns and abundances, with the endemic primates of Madagascar as an empirical system. The abundance of 11 primate species was estimated along gradients of elevation, food resource abundance and anthropogenic habitat disturbance at local scales in south-east Madagascar...
July 2016: Journal of Animal Ecology
Darrell J Gaskin, Hossein Zare, Adil H Haider, Thomas A LaVeist
OBJECTIVE: To explore the association between quality of care for surgical and pneumonia patients and the racial/ethnic composition of hospitals' patients. DATA SOURCE: Our primary data were surgical and pneumonia processes of care indicators from the 2012 Medicare Hospital Compare Data. We merged this data with information from the 2011 American Hospital Association Annual Survey of Hospitals. We computed the racial and ethnic composition of hospital patients using 2008 data from the Healthcare Costs and Utilization Project...
June 2016: Health Services Research
Ping Shi, J Max Goodson, Mor-Li Hartman, Hatice Hasturk, Tina Yaskell, Jorel Vargas, Maryann Cugini, Roula Barake, Osama Alsmadi, Sabiha Al-Mutawa, Jitendra Ariga, Pramod Soparkar, Jawad Behbehani, Kazem Behbehani, Francine Welty
BACKGROUND: Binary definitions of the metabolic syndrome based on the presence of a particular number of individual risk factors are limited, particularly in the pediatric population. To address this limitation, we aimed at constructing composite and continuous metabolic syndrome scores (cmetS) to represent an overall measure of metabolic syndrome (MetS) in a large cohort of metabolically at-risk children, focusing on the use of the usual clinical parameters (waist circumference (WC) and systolic blood pressure (SBP), supplemented with two salivary surrogate variables (glucose and high density lipoprotein cholesterol (HDLC)...
2015: PloS One
Grace H Lo, Timothy E McAlindon, Gillian A Hawker, Jeffrey B Driban, Lori Lyn Price, Jing Song, Charles B Eaton, Marc C Hochberg, Rebecca D Jackson, C Kent Kwoh, Michael C Nevitt, Dorothy D Dunlop
OBJECTIVE: Pain is not always correlated with severity of radiographic osteoarthritis (OA), possibly because people modify activities to manage symptoms. Measures of symptoms that consider pain in the context of activity level may therefore provide greater discrimination than a measure of pain alone. We undertook this study to compare discrimination provided by a measure of pain alone with that provided by combined measures of pain in the context of physical activity across radiographic OA severity levels...
November 2015: Arthritis & Rheumatology
Alya Al-Kaff, Sarah C MacDonald, Nancy Kent, Jason Burrows, Erik D Skarsgard, Jennifer A Hutcheon
OBJECTIVE: The purpose of this study was to determine the influence of planned mode and planned timing of delivery on neonatal outcomes in infants with gastroschisis. STUDY DESIGN: Data from the Canadian Pediatric Surgery Network cohort were used to identify 519 fetuses with isolated gastroschisis who were delivered at all tertiary-level perinatal centers in Canada from 2005-2013 (n = 16). Neonatal outcomes (including length of stay, duration of total parenteral nutrition, and a composite of perinatal death or prolonged exclusive total parenteral nutrition) were compared according to the 32-week gestation planned mode and timing of delivery with the use of the multivariable quantile and logistic regression...
October 2015: American Journal of Obstetrics and Gynecology
Seiji Miyazono, Reynaldo Patiño, Christopher M Taylor
This study determined long-term changes in fish assemblages, river discharge, salinity, and local precipitation, and examined hydrological drivers of biotic homogenization in a dryland river ecosystem, the Trans-Pecos region of the Rio Grande/Rio Bravo del Norte (USA/Mexico). Historical (1977-1989) and current (2010-2011) fish assemblages were analyzed by rarefaction analysis (species richness), nonmetric multidimensional scaling (composition/variability), multiresponse permutation procedures (composition), and paired t-test (variability)...
April 1, 2015: Science of the Total Environment
Anna Peeters, Emma Gearon, Kathryn Backholer, Bendix Carstensen
PURPOSE: We analyzed the changes in the body mass index (BMI) distribution for urban Australian adults between 1980 and 2007. METHODS: We used data from participants of six consecutive Australian nation-wide surveys with measured weight and height between 1980 and 2007. We used quantile regression to estimate mean BMI (for percentiles of BMI) and prevalence of severe obesity, modeled by natural splines in age, date of birth, and survey date. RESULTS: Since 1980, the right skew in the BMI distribution for Australian adults has increased greatly for men and women, driven by increases in skew associated with age and birth cohort/period...
January 2015: Annals of Epidemiology
Julien Rousseaux, Alain Duhamel, Dominique Turck, Denes Molnar, Julia Salleron, Enrique Garcia Artero, Stefaan De Henauw, Sabine Dietrich, Yannis Manios, Raffaela Piccinelli, Michael Sjöström, Luis Aznar Moreno, Frédéric Gottrand
OBJECTIVE: The question of whether breastfeeding has a protective effect against the development of overweight or obesity later in life remains controversial, especially during adolescence. The objective was to assess the relationship between breastfeeding and adolescents' body composition. METHODS: The HELENA study is a cross-sectional study involving 3,528 adolescents from 10 European cities. The outcome measures were body weight and height, subscapular skinfolds as well as waist circumferences...
2014: Obesity Facts
Ibrahim M Abbass, Salim S Virani, J Michael Swint, Wenyaw Chan, Luisa Franzini
BACKGROUND: Observation services are provided in greatly variant settings. The aim of this study was to reexamine the effectiveness of observation services compared to inpatient units for patients with nonspecific chest pain. HYPOTHESIS: Patients admitted to observation units have similar outcomes to patients admitted to inpatient wards. METHODS: We conducted a claim-based retrospective study for 7549 patients who were admitted to observation and inpatient units...
October 2014: Clinical Cardiology
Scott A Parsons, Robert A Congdon, Ivan R Lawler
Litter decomposition is a key ecosystem process, yet our understanding of the drivers in chemical changes in leaves during decay is limited. Our aim was to determine the comparative differences (chemical divergence or convergence) between sites and the drivers of decay pathways. We used the litterbag method ('in situ' litterfall and standardized 'control' leaves) in Australian tropical rainforests and near-infrared spectrometry to show the chemical pathways during decomposition (c. 360 d; 12 control sites; 17 in situ sites)...
August 2014: New Phytologist
Anke L B Günther, Helena Walz, Anja Kroke, Stefan A Wudy, Christina Riedel, Rüdiger von Kries, Gesa Joslowski, Thomas Remer, Guo Cheng, Anette E Buyken
BACKGROUND: Breastfeeding may lower chronic disease risk by long-term effects on hormonal status and adiposity, but the relations remain uncertain. OBJECTIVE: To prospectively investigate the association of breastfeeding with the growth hormone- (GH) insulin-like growth factor- (IGF) axis, insulin sensitivity, body composition and body fat distribution in younger adulthood (18-37 years). DESIGN: Data from 233 (54% female) participants of a German cohort, the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) Study, with prospective data on infant feeding were analyzed...
2013: PloS One
Brian K Sorrell, Chris C Tanner, Hans Brix
BACKGROUND AND AIMS: Plant species composition in wetlands and on lakeshores often shows dramatic zonation, which is frequently ascribed to differences in flooding tolerance. This study compared the growth responses to water depth of three species (Phormium tenax, Carex secta and Typha orientalis) differing in depth preferences in wetlands, using non-linear and quantile regression analyses to establish how flooding tolerance can explain field zonation. METHODOLOGY: Plants were established for 8 months in outdoor cultures in waterlogged soil without standing water, and then randomly allocated to water depths from 0 to 0...
2012: AoB Plants
Stanley R Bailey, Mara Loveman, Jeronimo O Muniz
Quantitative analyses of racial disparities typically rely on a single categorical measure to operationalize race. We demonstrate the value of an approach that compares results obtained using various measures of race. Using a national probability sample of the Brazilian population that captured race in six formats, we first show how the racial composition of Brazil can shift from majority white to majority black depending on the classification scheme. In addition, using quantile regression, we find that racial disparities are most severe at the upper end of the income distribution; that racial disparities in earnings are larger when race is defined by interviewers rather than self-identified; and that those classified as "black" suffer a greater wage penalty than those classified as "brown...
January 2013: Social Science Research
Jane Greve, Lars Bo Andersen
This paper examines the effect of participating in a web-based health programme that promotes personal tracking of high school students' own measurements of a number of health-related parameters. Danish cross-sectional survey data were used to examine the effects of the health programme on various health measures. Both quantile regression models and standard ordinary least squares (OLS) models were used to explore the correlations between the students' participation in the health programme and their body mass index (BMI), body fat percentage, aerobic fitness, and well-being...
2012: Journal of Sports Sciences
Siobhan Leahy, Cian O'Neill, Rhoda Sohun, Clodagh Toomey, Philip Jakeman
Anthropometric data indicate that the human phenotype is changing. Today's adult is greater in stature, body mass and fat mass. Accurate measurement of body composition is necessary to maintain surveillance of obesity within the population and to evaluate associated interventions. The aim of the present study was to construct and validate generalised equations for percentage body fat (%BF) prediction from anthropometry in 1136 adult men and women. Reference values for %BF were obtained using dual-energy X-ray absorptiometry...
February 28, 2013: British Journal of Nutrition
Hui Green Cheng, Yue-Qin Huang, Zhaorui Liu, Mingyuan Zhang, Sing Lee, Yucun Shen, Yanling He, James Christopher Anthony, Ronald C Kessler
Recently active mental disorders are associated with substantial disability, but there is little research on residual disability once symptoms have subsided. The aim of this study is to estimate the degree to which recent disability might be due to recent or past history of mental disorders using a quantile regressions (QR) model that makes it possible to study the full range of disability. Data were from cross-sectional surveys of Chinese living in Beijing and Shanghai, China (n=1628). The World Health Organization Disability Assessment Schedule and the WHO Composite International Diagnostic Interview were used to assess recent disability and common mental disorders, respectively...
October 30, 2012: Psychiatry Research
Meryl C Mims, Julian D Olden
The hydrologic regime is regarded as the primary driver of freshwater ecosystems, structuring the physical habitat template, providing connectivity, framing biotic interactions, and ultimately selecting for specific life histories of aquatic organisms. In the present study, we tested ecological theory predicting directional relationships between major dimensions of the flow regime and life history composition of fish assemblages in perennial free-flowing rivers throughout the continental United States. Using long-term discharge records and fish trait and survey data for 109 stream locations, we found that 11 out of 18 relationships (61%) tested between the three life history strategies (opportunistic, periodic, and equilibrium) and six hydrologic metrics (two each describing flow variability, predictability, and seasonality) were statistically significant (P < or = 0...
January 2012: Ecology
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"