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Substantial Correlation (substantial + correlation)
Selected AbstractsThe Illness/Injury Sensitivity Index: an examination of construct validityDEPRESSION AND ANXIETY, Issue 6 2006R. Nicholas Carleton M.A. Abstract The 11-item Illness/Injury Sensitivity Index [ISI; Taylor, 1993: J Behav Ther Exp Psychiatry 24:289,299] measures fears of injury and illness and has the potential to delineate some mechanisms underlying anxiety-associated chronic health conditions. In a principal components analysis in 2005, Carleton et al. [2005a: J Psychopathol Behav Assess 27:235,241] indicated that a two-factor solution (Fear of Injury and Fear of Illness) best explained the structure of the ISI. The primary purpose of this study was to examine the structural and construct validity of the ISI. Results supported a two-factor solution after removal of two overinclusive items. Although the measure demonstrated good factorial validity, convergent and discriminant validity require further evaluation. In addition, a substantial correlation with fear of pain suggests a shift in our perspective on what constitutes a fundamental fear. Future research implications are discussed. Depression and Anxiety 23:340,346, 2006. © 2006 Wiley-Liss, Inc. [source] DIFFERENTIATION AMONG POPULATIONS WITH MIGRATION, MUTATION, AND DRIFT: IMPLICATIONS FOR GENETIC INFERENCEEVOLUTION, Issue 1 2006Seongho Song Abstract Populations may become differentiated from one another as a result of genetic drift. The amounts and patterns of differentiation at neutral loci are determined by local population sizes, migration rates among populations, and mutation rates. We provide exact analytical expressions for the mean, variance, and covariance of a stochastic model for hierarchically structured populations subject to migration, mutation, and drift. In addition to the expected correlation in allele frequencies among populations in the same geographic region, we demonstrate that there is a substantial correlation in allele frequencies among regions at the top level of the hierarchy. We propose a hierarchical Bayesian model for inference of Wright's F -statistics in a two-level hierarchy in which we estimate the among-region correlation in allele frequencies by substituting replication across loci for replication across time. We illustrate the approach through an analysis of human microsatellite data, and we show that approaches ignoring the among-region correlation in allele frequencies underestimate the amount of genetic differentiation among major geographic population groups by approximately 30%. Finally, we discuss the implications of these results for the use and interpretation of F -statistics in evolutionary studies. [source] Genome-wide pleiotropy of osteoporosis-related phenotypes: The framingham studyJOURNAL OF BONE AND MINERAL RESEARCH, Issue 7 2010David Karasik Abstract Genome-wide association studies offer an unbiased approach to identify new candidate genes for osteoporosis. We examined the Affymetrix 500K,+,50K SNP GeneChip marker sets for associations with multiple osteoporosis-related traits at various skeletal sites, including bone mineral density (BMD, hip and spine), heel ultrasound, and hip geometric indices in the Framingham Osteoporosis Study. We evaluated 433,510 single-nucleotide polymorphisms (SNPs) in 2073 women (mean age 65 years), members of two-generational families. Variance components analysis was performed to estimate phenotypic, genetic, and environmental correlations (,P, ,G, and ,E) among bone traits. Linear mixed-effects models were used to test associations between SNPs and multivariable-adjusted trait values. We evaluated the proportion of SNPs associated with pairs of the traits at a nominal significance threshold ,,=,0.01. We found substantial correlation between the proportion of associated SNPs and the ,P and ,G (r,=,0.91 and 0.84, respectively) but much lower with ,E (r,=,0.38). Thus, for example, hip and spine BMD had 6.8% associated SNPs in common, corresponding to ,P,=,0.55 and ,G,=,0.66 between them. Fewer SNPs were associated with both BMD and any of the hip geometric traits (eg, femoral neck and shaft width, section moduli, neck shaft angle, and neck length); ,G between BMD and geometric traits ranged from ,0.24 to +0.40. In conclusion, we examined relationships between osteoporosis-related traits based on genome-wide associations. Most of the similarity between the quantitative bone phenotypes may be attributed to pleiotropic effects of genes. This knowledge may prove helpful in defining the best phenotypes to be used in genetic studies of osteoporosis. © 2010 American Society for Bone and Mineral Research [source] Trained lay observers can reliably assess medical students' communication skillsMEDICAL EDUCATION, Issue 7 2009George R Bergus Context, Our project investigated whether trained lay observers can reliably assess the communication skills of medical students by observing their patient encounters in an out-patient clinic. Methods, During a paediatrics clerkship, trained lay observers (standardised observers [SOs]) assessed the communication skills of Year 3 medical students while the students interviewed patients. These observers accompanied students into examination rooms in an out-patient clinic and completed a 15-item communication skills checklist during the encounter. The reliability of the communication skills scores was calculated using generalisability analysis. Students rated the experience and the validity of the assessment. The communication skills scores recorded by the SOs in the clinic were correlated with communication skills scores on a paediatrics objective structured clinical examination (OSCE). Results, Standardised observers accompanied a total of 51 medical students and watched 199 of their encounters with paediatric patients. The reliability of the communication skills scores from nine observed patient encounters was calculated to be 0.80. There was substantial correlation between the communication skills scores awarded by the clinic observers and students' communication skills scores on their OSCE cases (r = 0.53, P < 0.001). Following 83.8% of the encounters, students strongly agreed that the observer had not interfered with their interaction with the patient. After 95.8% of the encounters, students agreed or strongly agreed that the observers' scoring of their communication skills was valid. Conclusions, Standardised observers can reliably assess the communication skills of medical students during clinical encounters with patients and are well accepted by students. [source] Normal and Abnormal Personality Traits: Evidence for Genetic and Environmental Relationships in the Minnesota Study of Twins Reared ApartJOURNAL OF PERSONALITY, Issue 5 2002Kristian E. Markon ABSTRACT Recent studies have demonstrated substantial correlations between normal and abnormal personality traits. Yet little is known about how these correlations are mediated genetically and environmentally: Do normal and abnormal personality traits stem from the same underlying genes and environments? We addressed this question using data from 128 monozygotic and dizygotic twin pairs in the Minnesota Study of Twins Reared Apart (MISTRA). Additive genetic and nonshared environmental correlations between scales of the Minnesota Multiphasic Personality Inventory (MMPI),an index of abnormal personality,and the Multidimensional Personality Questionnaire (MPQ),an index of normal personality,were estimated. Results indicated that phenotypic correlations between normal and abnormal personality were mediated by genetic as well as environmental factors, although the magnitude of genetic mediation tended to be larger overall. Moreover, the patterns of phenotypic, genetic, and environmental relationships among the scales were similar, suggesting that influences on normal and abnormal personality act through systems common to both. It is suggested that future research focus on the neurogenetic substrates of these shared systems and how dysfunction in these systems influences development of disordered personality. [source] Common Genetic Contributions to Alcohol and Cannabis Use and Dependence SymptomatologyALCOHOLISM, Issue 3 2010Carolyn E. Sartor Background:, Despite mounting evidence that use of and dependence on alcohol and cannabis are influenced by heritable factors, the extent to which heritable influences on these phenotypes overlap across the 2 substances has only rarely been explored. In the current study, we quantified cross-substance overlap in sources of variance and estimated the degree to which within-substance associations between use and dependence measures are attributable to common genetic and environmental factors for alcohol and cannabis. Methods:, The sample was comprised of 6,257 individuals (2,761 complete twin pairs and 735 singletons) from the Australian Twin Registry, aged 24 to 36 years. Alcohol and cannabis use histories were collected via telephone diagnostic interviews and used to derive an alcohol consumption factor, a frequency measure for cannabis use, and DSM-IV alcohol and cannabis dependence symptom counts. Standard genetic analyses were conducted to produce a quadrivariate model that provided estimates of overlap in genetic and environmental influences across the 4 phenotypes. Results:, Over 60% of variance in alcohol consumption, cannabis use, and cannabis dependence symptoms, and just under 50% of variance in alcohol dependence (AD) symptoms were attributable to genetic sources. Shared environmental factors did not contribute significantly to the 4 phenotypes. Nearly complete overlap in heritable influences was observed for within-substance measures of use and dependence symptoms. Genetic correlations across substances were 0.68 and 0.62 for use and dependence symptoms, respectively. Conclusions:, Common heritable influences were evident for alcohol and cannabis use and for AD and cannabis dependence symptomatology, but findings indicate that substance-specific influences account for the majority of the genetic variance in the cannabis use and dependence phenotypes. By contrast, the substantial correlations between alcohol use and AD symptoms and between cannabis use and cannabis dependence symptoms suggest that measures of heaviness of use capture much of the same genetic liability to alcohol- and cannabis-related problems as dependence symptomatology. [source] | ||||||||||