Search results for "statistical"
showing 10 items of 4960 documents
Measuring Spatiotemporal Dependencies in Bivariate Temporal Random Sets with Applications to Cell Biology
2008
Analyzing spatiotemporal dependencies between different types of events is highly relevant to many biological phenomena (e.g., signaling and trafficking), especially as advances in probes and microscopy have facilitated the imaging of dynamic processes in living cells. For many types of events, the segmented areas can overlap spatially and temporally, forming random clumps. In this paper, we model the binary image sequences of two different event types as a realization of a bivariate temporal random set and propose a nonparametric approach to quantify spatial and spatiotemporal interrelations using the pair correlation, cross-covariance, and the Ripley K functions. Based on these summary st…
Diagnostic accuracy of adding copeptin to cardiac troponin for non-ST-elevation myocardial infarction: A systematic review and meta-analysis.
2018
Introduction This study aimed to determine the diagnostic accuracy of adding copeptin to cardiac troponin (cTn) on admission to the emergency department (ED) for non-ST elevation myocardial infarction (NSTEMI) compared to cTn alone. Materials and methods A literature search of MEDLINE, EMBASE, and the Cochrane Library was performed (search date: April 13, 2018). Primary studies were included if they accurately reported on patients with symptoms suggestive of acute myocardial infarction and measured both cTn alone and cTn with copeptin upon admission to the ED. The patients with evidence of ST elevation myocardial infarction were excluded. To assess the risk of bias for the included studies,…
Applying univariate vs. multivariate statistics to investigate therapeutic efficacy in (pre)clinical trials: A Monte Carlo simulation study on the ex…
2020
BackgroundSmall sample sizes combined with multiple correlated endpoints pose a major challenge in the statistical analysis of preclinical neurotrauma studies. The standard approach of applying univariate tests on individual response variables has the advantage of simplicity of interpretation, but it fails to account for the covariance/correlation in the data. In contrast, multivariate statistical techniques might more adequately capture the multi-dimensional pathophysiological pattern of neurotrauma and therefore provide increased sensitivity to detect treatment effects.ResultsWe systematically evaluated the performance of univariate ANOVA, Welch's ANOVA and linear mixed effects models ver…
Numerical Study of the semiclassical limit of the Davey-Stewartson II equations
2014
We present the first detailed numerical study of the semiclassical limit of the Davey–Stewartson II equations both for the focusing and the defocusing variant. We concentrate on rapidly decreasing initial data with a single hump. The formal limit of these equations for vanishing semiclassical parameter , the semiclassical equations, is numerically integrated up to the formation of a shock. The use of parallelized algorithms allows one to determine the critical time tc and the critical solution for these 2 + 1-dimensional shocks. It is shown that the solutions generically break in isolated points similarly to the case of the 1 + 1-dimensional cubic nonlinear Schrodinger equation, i.e., cubic…
Universality of the Triangular Theory of Love: Adaptation and Psychometric Properties of the Triangular Love Scale in 25 Countries
2021
The Triangular Theory of Love (measured with Sternberg’s Triangular Love Scale – STLS) is a prominent theoretical concept in empirical research on love. To expand the culturally homogeneous body of previous psychometric research regarding the STLS, we conducted a large-scale cross-cultural study with the use of this scale. In total, we examined more than 11,000 respondents, but as a result of applied exclusion criteria, the final analyses were based on a sample of 7332 participants from 25 countries (from all inhabited continents). We tested configural invariance, metric invariance, and scalar invariance, all of which confirmed the cultural universality of the theoretical construct of love …
Testing Measurement Invariance Across Spanish and English Versions of the Physical Self-Description Questionnaire : An Application of Exploratory Str…
2014
Test of measurement invariance across translated versions of questionnaires is a critical prerequisite to comparing scores on the different versions. In this study, we used exploratory structural equation modeling (ESEM) as an alternative approach to evaluate the measurement invariance of the Spanish version of the Physical Self-Description Questionnaire (PSDQ). The two versions were administered to large samples of Australian and Spanish adolescents. First, we compared the CFA and ESEM approaches and showed that ESEM fitted the data much better and resulted in substantially more differentiated factors. We then tested measurement invariance with a 13-model ESEM taxonomy. Results justified u…
Cross-Cultural Validity of the Physical Self-Description Questionnaire: Comparison of Factor Structures in Australia, Spain, and Turkey
2002
Abstract We evaluated the cross-cultural generalizability of the factor structure for the Physical Self-Description Questionnaire (PSDQ) using confirmatory factor analysis. The factor structure was reasonably invariant over large samples of responses by Australian, Spanish, and Turkish students. Consistent with a priori predictions, the factor structures based on Australian and Spanish high school students were somewhat more similar to each other than to those based on Turkish university students, but these differences were small. Psychometric, theoretical, cross-cultural, and practical considerations support the PSDQ's usefulness in a variety of research and applied settings. The study als…
A Confirmatory Factor Analysis of the “Autoconcepto Forma 5” Questionnaire in Young Adults from Spain and Chile
2011
The aim of this work is to examine the pentafactorial validity of the AF5 Self-Concept Questionnaire in Spanish and Chilean young adults. From the responses of a total of 4,383 young adults aged 17 to 22 years (1,918 Spanish, 44%, and 2,465 Chilean, 56%) it was analyzed the reliability of the instrument, the compared validity of the 5 oblique factor model proposed by the authors versus the unifactorial and the orthogonal alternative models, and was studied the invariance of one Chilean sample. The results of confirmatory factor analyses supported the authors' pentafactorial model. The multi-group factorial invariance showed that Chilean sample of the AF5 does not change neither the Spanish …
Smoking trends among adolescents from 1990 to 2002 in ten European countries and Canada.
2006
Abstract Background Daily smoking adolescents are a public health problem as they are more likely to become adult smokers and to develop smoking-related health problems later on in their lives. Methods The study is part of the four-yearly, cross-national Health Behaviour in School-aged Children study, a school-based survey on a nationally representative sample using a standardised methodology. Data of 4 survey periods are available (1990–2002). Gender-specific daily smoking trends among 14–15 year olds are examined using logistic regressions. Sex ratios are calculated for each survey period and country. Interaction effects between period and gender are examined. Results Daily smoking preval…
Compassion Satisfaction, Compassion Fatigue, and Burnout in Spain and Brazil: ProQOL Validation and Cross-cultural Diagnosis
2017
Abstract Context Palliative care professionals' quality of life has emerged as a growing issue of interest in health care literature, centered on concerns about professionals' compassion within a context of work characterized by pain and death. Objectives The aim of this study was threefold: 1) to study the psychometric properties of both the Spanish and the Portuguese versions of the ProQOL scale, by means of confirmatory factor analyses; 2) to offer a diagnosis of compassion satisfaction and compassion fatigue levels of Spanish and Brazilian palliative care professionals; and 3) to compare levels in ProQOL between countries. Methods Two surveys with a cross-sectional design were carried o…