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Results for “canonical correlation analysis”

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PubMed1995

Rigid-body motions of sub-units in DNA: a correlation analysis of a 200 ps molecular dynamics simulation.

A 200 ps molecular dynamics simulation of the B-form double stranded self-complementary octanucleotide d(CTGATCAG) is analyzed in terms of correlated motions using the canonical analysis approach. Each nucleotide is decomposed in three sub-units corresponding to the base, the sugar ring and the backbone respectively. The correlation between the full dynamics of two sub-units was found to decrease as their mutual distance increases. The interpretation of the full dynamics of sub-units as the superimposition of rigid-body motions (translation and orientation) and deformation shows that the main source of correlation is rigid-body motions. Correlation between sub-units deformation is weak and practically vanishes for sub-units belonging to non-adjacent nucleotides. It is also shown that the correlation is much more important for sub-units of the same strand than of opposite strands. We conclude that the internal dynamics of the octanucleotide may be well described by rigid-body motions, the sub-units deformation having only local influence whereas sub-units translation and rotation have repercussion to long distances. The results presented in this study suggest how the number of degrees of freedom may be reduced for simulating long-time dynamics of oligonucleotides.

Computer Simulation↗

PubMed1988

Sub-cutaneous fat thickness measured by magnetic resonance imaging, ultrasound, and calipers.

Sub-cutaneous fat thickness was measured at 12 sites on the body surface of 24 males and 26 females using magnetic resonance imaging (MRI), skinfold calipers, and A-mode ultrasound. The mean of the 12 fat thickness measurements and individual site thicknesses were compared between individuals using analysis of variance. In males, the mean thicknesses for ultrasound and calipers were similar (P greater than 0.05) but both were less than the MRI (P less than 0.001). MRI and ultrasound were similar in females but less than calipers (P less than 0.001). A good between-subject correlation was found between all three methods in the males but only the calipers and MRI were well correlated in females. Within-subject correlations are poor for all measures and in both sexes. Factor loadings for a varimax rotation of two principal components indicate that the fat is distributed in 1 of 2 patterns: either principally on the trunk or on the limbs. The principal component analysis and the result of canonical correlations obtained from the factor loadings confirm the findings of the analysis of variance, in that a general level of fatness is measurable by all three methods over a range of subjects. However, the pattern of fat thicknesses measured over a number of specific sites by one method of measurement is unlikely to be duplicated by either of the other two methods on the same individual.

Adipose Tissue↗

PubMed2000

Relation of abdominal height to cardiovascular risk factors in young adults: the Bogalusa heart study.

Obesity and fat patterns are important predictors of coronary heart disease risk. The relations of abdominal height (sagittal diameter) and various obesity measures to coronary heart disease risk factors were examined in a community-based sample of 409 Blacks and 1,011 Whites aged 20-38 years in Bogalusa, Louisiana (1995-1996). Obesity measures used included weight, waist circumference, waist:hip ratio, waist:height ratio, abdominal height, triceps and subscapular skinfold thicknesses, body mass index, and conicity index. Abdominal height was highly correlated with other obesity measures, especially waist circumference (0.937-0.944, p < 0.001), and was least correlated with height. In multivariate analysis, abdominal height was an independent predictor of levels of total cholesterol, triglycerides, very low density lipoprotein cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, glucose, and insulin and of systolic and diastolic blood pressures (p < 0.05 to p < 0.001), with total R2 values ranging from 0.13 to 0.52. Abdominal height contributed more to the prediction of blood pressure than did other measures of central obesity. In canonical analysis, abdominal height was correlated more strongly with the coronary disease risk factor variables as a group than were other obesity measures. These results suggest that abdominal height adds another dimension to measures of obesity in that it may help to assess a component of visceral fat that other measures miss.

Abdomen↗

PubMed2000

Groningen active living model (GALM): stimulating physical activity in sedentary older adults; first results.

BACKGROUND: A significant proportion of older adults in The Netherlands does not regularly participate in leisure-time physical activity. The Groningen Active Living Model (GALM) was developed to change this situation for the better. In this article the first results with respect to the validation of the model are presented. METHODS: We obtained cross-sectional data from a sample of 392 potential participants. Scores on the potentially causal variables (self-efficacy, social support, perceived fitness, and enjoyment) and the stages of change give a first indication of the potential validity of the GALM behavioral change model. RESULTS: Seventeen percent of the subjects could be categorized as in the precontemplation stage, 42% in the contemplation/preparation stage, and 39% in the action/maintenance stage. Data with respect to stages of change were missing for 2% of the subjects. Scores on all potentially causal variables rose significantly from the precontemplation to the action/maintenance stage. Discriminant analysis resulted in a canonical correlation of 0.58 between the precontemplation and the contemplation/preparation stages and 0.59 between the contemplation/preparation and action/maintenance stages; respectively, 82.6 and 78.3% of the subjects had been classified correctly. CONCLUSIONS: The results found in this study support our hypothesis, as described in the conceptual theory of the GALM behavioral change model. For a more comprehensive validation of the model's action theory and conceptual theory, follow-up measurements are required.

Aged↗

PubMed1984

Faculty and administrator perceptions of decision making.

This research study was conducted in associate and baccalaureate schools of nursing. This research focused on the extent of faculty participation in decision making; a description and analysis of the characteristics of nurse faculty, nurse administrators, and the organizations of associate and baccalaureate schools of nursing; the interrelationships between opportunities for participation in decision making and the level and type of decision making; the relationships between various personal and situational variables that affect decision making, the relationship between the type of involvement in decision making to the variables of job satisfaction, professional commitment, and job tension; and the relationships among the variables of job satisfaction, professional commitment and job tension. Ninety-three faculty and 10 administrators participated in the research study. Research data were collected by three instruments: the School Information Profile, the Administrative Questionnaire, and the Faculty Questionnaire. The data were subjected to frequency distribution statistics, the RELIABILITY program of SPSS, Pearson correlation coefficients, Canonical correlations, and Multiple Regression analysis. The primary study results were: Faculty reported that their participation in decision making is primarily in the area of making recommendations, not final determinations. Faculty stated that decision making is usually a group process. Administrator perceptions were that faculty possess more decision-making power than faculty believed. Faculty reaffirmed that job satisfaction and professional commitment are positively correlated, and that job tension was found to be negatively correlated to job satisfaction and professional commitment.(ABSTRACT TRUNCATED AT 250 WORDS)

Administrative Personnel↗

PubMed2006

Differences in blood pregnenolone and dehydroepiandrosterone levels between schizophrenia patients and healthy subjects.

BACKGROUND AND OBJECTIVE: Contradictory and confusing reports on serum dehydroepiandrosterone (DHEA) levels in schizophrenia led us to compare the serum concentration of its precursor, pregnenolone (PREG), between medicated schizophrenia patients and healthy subjects. The neurosteroid levels were monitored for two months and the relationship of these neurosteroids with schizophrenic symptomatology, emotional distress, and anxiety was examined. METHOD: We determined blood levels of PREG, and DHEA in 15 schizophrenia patients and 12 healthy controls at four time points: at the start of the study, after 2, 4 and 8 weeks. Analysis of covariance and canonical correlations across four time points were applied. RESULTS: Controlling for age, serum concentrations of PREG were lower, while the DHEA level and the molar ratio values of DHEA/PREG were higher in schizophrenia patients compared to healthy controls. Both levels of PREG and DHEA and their molar ratio did not change significantly during the study's period either among schizophrenia patients or healthy controls. The blood levels of PREG appear to be associated with trait-anxiety scores in the schizophrenia patients, while associations of clinical symptoms with two neurosteroids did not reach a significant level when the confounding effect of emotional distress, and anxiety scores was controlled. CONCLUSION: Low serum pregnenolone concentrations in schizophrenia appear to be associated with trait-anxiety scores independent of symptoms. Further research into the role of pregnenolone in schizophrenia is warranted.

Adult↗

PubMed1984

What affects fetal pulmonary maturation during diabetic pregnancy?

Previous studies differ as to whether the fetus of the woman with diabetes mellitus has altered formation of lung surfactant. The factors responsible for these differences remain unclear. In this study, measures of blood glucose control, including birth weight percentile and the presence of factors potentially influencing fetal pulmonary maturation, such as diabetic class, maternal chronic hypertension, and preeclampsia, were compared with the amniotic fluid lecithin/sphingomyelin ratio, phosphatidylglycerol, and phosphatidylinositol within a group of 90 diabetic pregnancies. The factors were evaluated in combination with the techniques of canonical correlation and multiple regression analysis. Gestational age had the strongest effect in determining levels of amniotic fluid phospholipids, and hypertension was found to significantly accelerate the appearance of phosphatidylgycerol (p less than 0.05). The effect of hypertension was one third as important as that of gestational age. Neither diabetic blood glucose control, White classification, nor the remaining explanatory variables were found to play a significant role in determining the amniotic fluid phospholipid levels. This study suggests that, in the clinical management of diabetes, gestational duration remains the single most important determinant of amniotic fluid phospholipid levels.

Amniotic Fluid↗

PubMed1985

Predictive validity of the MCAT for students with two sets of scores.

Addressed in the study reported here is the question of which set of scores for those students who retake the Medical College Admission Test (MCAT) yields a better predictive validity. The sample was comprised of 304 students who retook the MCAT prior to entering Jefferson Medical College between 1978 and 1981. Five sets of MCAT scores were considered as predictors in the study: earlier, later, higher, and lower sets of MCAT scores and the average of the earlier and later scores for each MCAT subtest. Twenty-five criteria were used, including grades earned in the freshman and sophomore years and scores on the subtests of Part I and Part II of the examinations of the National Board of Medical Examiners. Correlational techniques, such as bivariate and multiple correlation analyses and canonical correlation followed by redundancy analysis were utilized. The magnitude of redundancy indices indicated that the set of MCAT scores in which the earlier and later scores were averaged was the best predictor, followed by the earlier, lower, higher, and later sets of MCAT scores. The implications of these findings for the admissions process and for validity studies are discussed.

Achievement↗

PubMed1986

The validity of clerkship performance evaluations.

The validity of narrative evaluations of clinical performance in medical school was investigated for three successive classes of medical school graduates. The criteria were ratings obtained from residency supervisors one year after entering the programme. Bivariate correlational analysis, multiple regression analysis and canonical redundancy analysis were performed to examine the associations between the evaluations by teachers of competence in medical school clerkships and the subsequent ratings by residency supervisors. The results, best summarized in the canonical analysis, showed two relationships between the two sets of measures (lambda 1 = 0.54 and lambda 2 = 0.47). The first relationship revealed an overall-competence-in-medicine dimension; the second suggested an interpersonal-skills/professional-maturity dimension. Overall, knowledge of clerkship performance accounted for 15% of the variance in residency ratings. The findings suggest the need to improve the assessment of professional maturity and behaviour during medical school.

Clinical Clerkship↗

PubMed1985

Apolipoproteins and lipoproteins in children with type I diabetes: relation to glycosylated serum protein and HbA1.

Serum levels of cholesterol (C), triglycerides (TG), lipoprotein-C and apolipoproteins (apo) A-I, A-II and B were measured in 30 children with type I diabetes mellitus (16 boys, 14 girls, aged 11-14 years) and in 26 healthy controls (15 boys, 11 girls, aged 10-13 years). For 19 diabetics controls matched for age, sex and relative body weight were selected. The diabetic patients were considered to be in fair metabolic control according to HbA1 levels and glycosylated serum protein concentrations. Mean serum apo A-I, A-II and B, C, TG, low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) did not differ significantly between diabetic nondiabetic children. Very low density lipoprotein cholesterol (VLDL-C) was significantly higher in diabetic children than in controls. Serum C and LDL-C levels showed close univariate linear correlations with glycosylated serum protein (LDL-C: r = 0.53, p less than 0.01, C: r = 0.58, p less than 0.01) in diabetics. The ratio LDL/HDL-C was significantly correlated to HbA1 levels (r = 0.47, p less than 0.01). By canonical and multiple linear correlation analysis significant relations of a selected set of variables concerning the control and therapy of diabetes (serum glucose, HbA1, glycosylated serum protein, insulin dose) with a set of lipoprotein variables (C, TG, VLDL-C, HDL-C, LDL-C, apo A-I, A-II, B) could be demonstrated. From these data we conclude that significant relations between atherogenic serum lipids and lipoproteins (C, LDL-C) and the degree of metabolic control exist in diabetic children, even in the absence of marked dyslipoproteinemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1988

Subjective well-being among the rural elderly population.

The purpose of this study was to investigate the relationship between psychosocial factors and subjective well-being among rural elderly persons. A broad range of psychosocial factors (such as mastery, social support, and perceived health) and measures of well-being (such as positive and negative affect and life satisfaction) were employed in bivariate correlation, canonical correlation, and multiple regression analysis. The findings show significant relationships between subjective well-being measures and psychosocial factors that are concomitant with other populations, both elderly and general.

Age Factors↗

PubMed2000

[Lipid peroxidation and activity of diagnostically important blood enzymes in rats during 35 days head-down suspension].

In the experiment with 35-d head-down suspension of rats concentrations of lipid peroxidation (LPO) products and values of antioxidant defense (AOD) parameters were determined in the lever, skeletal muscles, myocardium, and blood plasma. In addition, activity of 11 plasma enzymes characteristics of these tissues was evaluated. LPO was found to be activated in the lever, myocardium and skeletal muscles in the first and 4-5 weeks of suspension. The period between weeks 2 and 4 marked phase variation of LPO intensity which could have baseline or increased values. Plasma LPO was inhibited due to AOD activation pointing to compensatory processes on the level of organism and absence of pathologies in the organs and tissues under study. As a rule, activity of the plasma enzymes directly or indirectly participating in energy metabolism was reduced. Enzymes-catalysts of other types of metabolism predominantly elevated activity during LPO intensification. Canonic analysis established a significant correlation of LPO, AOD and activity of plasma enzymes, and LPO and AOD in the rat's lever and plasma enzymes. These correlations between LPO, AOD and activity of diagnostically important enzymes can be used to diagnose and predict changes in the state of organism caused by simulated factors of space flight.

Animals↗

PubMed2003

Developmental interdependence between selected somatic features and the weight of internal organs in human male and female foetuses.

The study material comprised 3889 foetuses of both sexes, aged 20-42 weeks and focused on developmental interdependence between the weight of the internal organs and their relation to selected somatic features during the prenatal period. The study also attempted to distinguish potential sex-related differences in the degree of statistical interdependence between the analysed variables. As a result, the analysis of linear and canonical correlation coefficients for consecutive weeks of foetal life has been carried out. High correlation coefficients have been obtained which indicate strong developmental interdependence between those organs and the somatic features. However, no significant sex-related differences in the developmental interdependence of the analysed variables have been observed.

Anthropometry↗

PubMed1988

Canonical analysis of cells in normal and abnormal cervical smears.

Over 4,000 cells from 105 normal and 96 abnormal uterine cervical scrapes were prepared according to the UCLA monolayer procedure, stained by a routine Papanicolaou method and visually classified by two cytopathologists and a technologist into seven classes: parabasal, metaplastic, mild dysplasia, moderate dysplasia, severe dysplasia, carcinoma in situ and invasive carcinoma. Canonical analysis was used to correlate effects-coded class membership variables with 23 cell features derived from digital image analysis. In general, nuclear texture measures derived from linear combinations of run-length correlations along with features derived from a Markov transitional probability matrix provided the best predictors of cell class. After cells were divided into benign (moderate dysplasia or less) and malignant (severe dysplasia or worse) groups, discriminant analysis correctly classified 84% of the benign cells and 91% of the malignant cells.

Cell Nucleus↗

PubMedDate not supplied

Relationship between ethanol-induced changes in brain regional metabolism and its motor, behavioural and cognitive effects.

AIMS AND METHODS: Acute alcohol administration induces marked decreases in glucose metabolism throughout the human brain. However, the relationship between alcohol's effects on brain metabolism and the behavioural changes that occur with intoxication are still unclear. Here we assessed this association using principal component analysis for dimension reduction and canonical correlations to gauge inter-class relationships. We also used canonical correlations in the polynomial space to assess for possible nonlinear relationships. RESULTS: After normalizing the regional measures to account for the large whole brain decreases observed with intoxication we show that the largest decreases occurred in occipital cortex and that there were relative increases in basal ganglia. Principal component analysis of the changes in the normalized measures revealed that 60% of the variance was accounted for by two factors; one that contrasted cerebellum versus frontal and anterior cingulate metabolism, and another that contrasted basal ganglia and insula. The square of the first factor was significantly correlated with the deterioration in cognitive performance. The second factor showed a significant linear correlation with self-reports of intoxication and with deterioration in cognitive and motor performance. CONCLUSIONS: These findings suggest that the contrasting effects of alcohol in basal ganglia versus the insula are involved in the perception of 'feeling drunk' and that its contrasting effects in cerebellum versus those in frontal and parietal cortices are involved in its motor incoordinating effects. On the other hand alcohol's impact on cognitive performance implicates a more complex pattern of brain effects that includes linear as well as non-linear associations.

Adult↗

PubMed2001

LBNP as useful tool for pilot candidates selection to the Polish Air Force: a preliminary study.

BACKGROUND: Candidates to the Polish Air Force are to fulfill strict medical conditions. Every candidate, wanting to become a fighter pilot or not, has to pass a rigorous centrifuge examination. This is a costly and especially stressful process for the candidates, as first-timers. This article explores possibility for different approach to candidates fitness to fly assessment. METHODS: 14 candidates (21-22 yrs old) were subjected to a regular GOR centrifuge profile (0.1 G/s; up to +7.0 Gz; unprotected) and to lower body negative pressure (LBNP) examination (2 min. rest period followed by 3 min. at -40 mm Hg; supine position). Both, centrifuge and LBNP examinations were carried out the same day, with about 1 hour gap between them. ECG and impedance cardiography (ICG) were being recorded during both tests. The following parameters were calculated: HR and QZ (time between ventricular depolarization [beginning of the Q wave in ECG] and local maximum of the first derivative [dZ/dt] in ICG). QZ was considered to be an effective measure of dynamic heart function. RESULTS: +Gz tolerance for the group was +5.94 +/- 0.98 Gz. Correlation between +Gz tolerance and QZ values during LBNP test (-40 mm Hg) for all subjects was equal to r=0.6. Correlation between sets of parameters (canonical analysis) for LBNP and centrifuge was equal to r=0.78. Both results were statistically insignificant (p<0.09). Baseline HR values were 121 +/- 19 bpm and 75 +/- 12 bpm, and maximal HR values were 172 +/- 21 bpm and 81 +/- 13 bpm, respectively for centrifuge and LBNP. For both, baseline and maximal HR during LBNP and G exposure canonical correlation was equal to r=0.72. The results were statistically not significant, however. CONCLUSIONS: Centrifuge examination is much more stressful than LBNP test. This could have implication on the objective results of centrifuge test. The results may suggest that LBNP test could be a used in pilot candidates selection, especially those presenting high baseline HR values.

Adaptation, Physiological↗

PubMed2005

Informing cancer prevention strategies for African Americans: the relationship of African American acculturation to fruit, vegetable, and fat intake.

Acculturation has been associated with health-related behaviors in African Americans. We sought to determine if there is a relationship between acculturation and dietary intake in African Americans. African Americans in the PREMIER trial completed the African American Acculturation Scale (AAAS) and 2 nonconsecutive 24-h dietary recalls (n = 238). Analysis of variance (ANOVA) and canonical correlation were used to assess relationships between acculturation and dietary intakes. Canonical correlation (p = 0.05) showed that traditional African Americans had lower intakes of fruits/vegetables and milk/dairy with higher intakes of fats, meat, and nuts. This pattern was supported by differences in the ANOVA. African American acculturation is related to dietary intake. These findings have implications for the design of cancer-related public health messages targeted to African Americans.

Acculturation↗

PubMed2005

Association between physique characteristics and hand skeletal aging status.

The aim of the present study was to evaluate the association between skeletal aging traits (obtained from evaluation of hand radiographs) and physique characteristics, including indices of obesity, skeletal size, muscular development, and the somatotypes of Heath and Carter (1967) and of Deriabin (1985). To achieve our aims, we used multiple regression analysis, and Pearson's and canonical correlation analyses. The studied population comprised 629 males and 561 females aged 18-90 years, all members of the Chuvasha (Russian Federation). The present study provides evidence for a connection between hand bone aging traits and physique characteristics. The cortical index showed a small but significant correlation with adiposity and the index of overall physique, but bone mineral density (BMD) traits were not correlated with the index of overall physique. Deriabin's set of somatotypes was significantly correlated with BMD, but could explain only 2% of its variation. Significant correlations of the hand osteoarthritis trait were observed with indices of adiposity. Also observed were statistically significant canonical correlations with both sets of somatotypes, which enabled us to predict 2-3% of hand osteoarthritis variation by a combination of somatotype components. Osseometric score evinced statistically significant correlations with most indices of physique as well as with a combination of somatotype components. These findings may prove helpful in epidemiological studies, because they show that body composition is the factor that is statistically significantly associated with skeletal aging.

Adipose Tissue↗