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Results for “Discriminant Analysis”

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PubMed2005

Refinery firefighters: assessing fitness for duty.

Firefighting is a hazardous and physically demanding activity. The demanding nature of the tasks involved in firefighting requires a high level of fitness both for the safety of the firefighting personnel as well as for the adequate performance of their tasks. Here, the characteristics (body weight, lung function, etc.) of a small group of refinery firefighters were investigated using exploratory factor analysis and discriminant analysis. The results indicated that there is a group of factors that characterize those individuals meeting minimum fitness requirements as described previously in the literature. The factors that were identified included those related to anthropometry (such as body composition and weight) and those related to physical capabilities (such as push-ups). Since these data are collected relatively easily in most occupational settings, they may offer an efficient surrogate method to determine fitness for duty among firefighters.

Firefighters↗

PubMed1992

Prognostic factors for radiographic damage and physical disability in early rheumatoid arthritis. A prospective follow-up study of 147 patients.

We studied the influence of demographic, clinical, laboratory and genetic features and radiographic damage at onset on the outcome after 2 years in a prospective study of 147 patients with classical or definite RA with disease duration shorter than 1 year at entry. Outcome was determined by physical disability and by radiographic damage of hands and feet. By means of multiple regression analysis and discriminant analysis outcome was explained from variables at the start and during the first 6 months. No clinically relevant conclusions could be made for physical disability due to the low explained variance and small number of patients with bad physical disability. Radiographic damage after 2 years was predicted by high disease activity at the start (measured as erythrocyte sedimentation rate, C-reactive protein or Disease Activity Score) combined with DR4 or DR2 (as a prognostically favourable factor) and rheumatoid factor positivity. Radiographic damage could be better predicted if disease activity during the first 6 months was included. Absence or presence of progression of radiographic damage could be correctly predicted in 83% of the patients.

Adolescent↗

PubMed2002

Methotrexate in the treatment of rheumatoid arthritis. II. In vivo effects on bone mineral density.

OBJECTIVE: To determine the effect of methotrexate (MTX) on bone mineral density (BMD) in rheumatoid arthritis (RA). METHODS: One hundred and sixteen non-steroid-treated RA subjects (90 women) were studied in a prospective, longitudinal, non-randomized study. Subjects started MTX (n=36) or sulphasalazine (n=23) or continued long-term (>5 yr) treatment with MTX (n=28) or other disease-modifying anti-rheumatic drugs (n=29). BMD was estimated at entry and after 1 yr. Markers of bone turnover were measured at entry and at 1 yr, and additionally at 3 and 6 months in those starting treatment. Bone biopsies were taken before and after MTX treatment in four subjects. The primary outcome was change in BMD Z score and secondary outcomes were changes in bone turnover markers and bone formation by histomorphometry. RESULTS: Univariate analysis of covariance found that MTX at baseline was associated with reduced BMD at the femoral neck. However, femoral neck BMD was also associated with radiological damage score for the hand. Multivariate analysis and discriminant analysis of the subset of post-menopausal women showed that reduced bone density associated with MTX was due to confounders such as disease activity. There was no adverse effect of MTX on bone turnover markers or on measures of bone formation in biopsies. CONCLUSIONS: No adverse effect of low-dose MTX (mean 10 mg/week) on bone formation in RA was found.

Adult↗

PubMed1977

Sensitizing medical students to impression formation processes in the patient interview.

Medical students in a course that included instruction in patient interviewing participated in an experiment devised to alert them to sources of bias which might influence their judgements and management of patients. Students were randomly assigned to one of four groups and exposed to either a videotaped or audiotaped interview of the same patient presented as either normal weight or overweight. Questionnaire responses of students in the two audio groups indicated no detectable differences in the sound tracks of the overweight and normal weight versions of the interview, and these groups were combined for subsequent analysis. A discriminant analysis indicated that students exposed to the overweight video version formed impressions and assessed patient treatment and outcome differently from those exposed to either the video normal or audio versions of the interview. Implications of these findings for medical education are discussed, and suggestions are made for incorporating such sensitization experiments in the medical curriculum.

Attitude of Health Personnel↗

PubMed1977

Alternative regression approaches to the analysis of medical care survey data.

In a multivariate analysis of ambulatory care utilization of a subsample of the 1970 National Health Interview Survey (NHIS) data the dependent variables representing utilization, acute conditions and chronic conditions were found to have discrete variable properties violating normality assumptions of standard regression analysis. Focusing on the utilization variable, alternative multivariate approaches were compared with results obtained from standard least squares analysis. These were Poisson-based multivariate regression, logit analysis, and discriminant analysis. While the fixed interval measure of utlization had an L-shaped frequency distribution with considerable departure from normality, it was found that more theoretically appropriate alternatives provided only marginal gains over the standard least squares techniques.

Acute Disease↗

PubMedDate not supplied

Predictors of plasma triglyceride elevation in patients participating in a coronary atherosclerosis treatment program.

PURPOSE: Low-fat, high-carbohydrate diets have been used successfully to prevent and treat coronary heart disease, although these diets have been shown to cause elevations in fasting plasma triglyceride concentrations. The present study investigated metabolic factors (glucose, insulin, body weight) associated with changes in plasma triglyceride concentrations in patients participating in a comprehensive, multidisciplinary program, which included the use of a very low-fat diet designed to regress atherosclerotic cardiovascular disease. METHODS: Thirty-six patients were entered into the study and placed on a 10% fat diet. Body mass index and fasting plasma insulin, glucose, lipids, and apolipoproteins were assessed at entrance into and after 3 months of participation in the program. Statistical analysis (discriminant function analysis) was used to identify factors that predicted elevations in plasma triglyceride that occurred during therapy. RESULTS: For the entire group, significant reductions in body weight (-2.4%), fasting glucose (-6%), total cholesterol (-8%), and low-density lipoprotein cholesterol (-11%) were observed, while insulin and triglycerides showed no significant changes. Twenty-one of the patients experienced an increase in fasting triglyceride concentration of 10% or greater. CONCLUSIONS: Three variables (baseline body mass index and fasting triglyceride and insulin concentrations) accurately classified 90% of those who would experience a > or = 10% elevation in triglycerides (P = 0.0002) and 67% of those who experienced no change. The present analysis provides a practical algorithm for clinicians to predict which patients will experience significant elevations in plasma triglyceride concentration when undergoing risk factor reduction that includes the consumption of a very low-fat, high-carbohydrate diet.

Adult↗

PubMed1985

Carrier detection in factor VII congenital deficiency.

Thirty obligate and 28 possible carriers of factor VII congenital deficiency, belonging to 16 families, were studied in relation to the immunological variants to which the kindreds belonged, namely, VII+, VIIR and VII-. Factor VII activity and antigen determinations in these subjects formed two phenotypical patterns: a discrepant pattern characterized by a low ratio activity/antigen present in VII+ heterozygotes, and a non-discrepant pattern (normal ratio activity/antigen) which is present in the VII- and VIIR variants. In the first genetic variant the detection of carriers can be performed using the ratio VII:C/VII:Ag. In the other variant, which accounts for the vast majority of heterozygotes, the distribution of the carriers' factor VII is so widespread that a large overlap results between these subjects and the normals. The application of a probabilistic calculation performed by combining the actual values of factor VII:C and the genetic probability of carriership using Fisher's linear discriminant analysis, makes discrimination between carriers and normals easier.

Adolescent↗

PubMed1985

Morphometric assessment of reflux oesophagitis in fibreoptic biopsy specimens.

The oesophageal epithelium of patients with reflux oesophagitis has been studied by means of computer aided morphometry. Measurements of histological features were made on biopsies from six cases before and after treatment. The size and elongation of the nuclei and their variation, the number of nuclei per unit length or per unit sectioned area, and the size and number of nucleoli per nucleus were measured for two zones of the epithelium, the base layer and the intermediate layer, which were independent of section orientation. The measurements were analysed using discriminant analysis. Significant discrimination was found between the two groups. The most important parameters were the number of intermediate layer nuclei per sectioned square millimetre, the mean intermediate layer nuclear area, and the number of nuclei per millimetre of base epithelium. These parameters are consistent with increased cell turnover of the non-ulcerated epithelium before treatment.

Anti-Ulcer Agents↗

PubMed2006

Over-complete discrete wavelet transformation of the normal auditory brainstem response improves prediction of outcome following severe acute closed head injury.

Previous research has shown that complex statistical analysis (discriminant function analysis) of a 'normal' auditory brainstem response (ABR) result can improve this measure's ability to predict subject outcome following severe acute closed head injury (ACHI). We hypothesized that adding the ABR's time-frequency information to such an analysis would improve this predictive value even further. 'Normal' ABR results were sampled from 69 severe ACHI subjects (22 of whom died and 47 of whom lived) and their time-frequency information extracted using an over-complete discrete wavelet transformation (OCDWT). A series of logistic regression analyses then showed correct predictions of death and survival as follows: ABR measures only 72 and 89% (respectively), ABR OCDWT measures only 82 and 89% (respectively), and ABR and ABR OCDWT measures combined 86 and 93% (respectively). These results showed that the addition of time-frequency information can improve the ability of the 'normal' ABR result to predict outcome following severe ACHI.

Acoustic Stimulation↗

PubMed1981

Hemagglutination tests for tuberculosis with mycobacterial glycolipid antigens. Results in patients with active pulmonary tuberculosis before and during chemotherapy and in healthy tuberculosis contacts.

Hemagglutination tests using three serologically active mycobacterial glycolipids as antigens were carried out on serum specimens from patients with pulmonary tuberculosis and from healthy family contacts of patients with tuberculosis in Singapore. A positive response to any of the three antigens was found in 82.5% of 211 patients with newly diagnosed disease and in 21% of 100 contacts. The much higher proportion of positive results in the contacts than in other groups of healthy subjects previously reported might have been due to subclinical infection with tubercle bacilli or with other environmental mycobacteria. The use of rules derived from discriminant analysis improved discrimination between patients and contacts, so that a positive result was obtained in 72% of patients and 5% of contacts. Serial positive titers during 1 yr of chemotherapy showed an initial slight increase during the first month and then a slow decrease, although conversion from a serologically positive result to a negative result was uncommon. The occurrence of widely variable patterns of response to the three antigens in different patients emphasizes the importance of using a battery of tests, each with a separate antigen.

Adolescent↗

PubMed2003

The contribution of somatic symptoms to the diagnosis of depressive disorder in Parkinson's disease: a discriminant analytic approach.

This study assessed the sensitivity of individual depressive symptoms and their relative contribution to the diagnosis of depressive disorder in patients with Parkinson's disease. The Structured Clinical Interview for DSM-IV Depression and the Hamilton and Montgomery-Asberg depression rating scales (Ham-D, MADRS) were administered to 149 consecutive nondemented patients. The contribution of the individual items of these scales to the diagnosis of "depressive disorder" was calculated by discriminant analysis. The discriminant models based on the Ham-D and MADRS scores were both highly significant. Nonsomatic core symptoms of depression had the highest correlation coefficient. Somatic items had mostly low correlation coefficients, with the exception of reduced appetite and early morning wakening (late insomnia). Nonsomatic symptoms of depression appear to be the most important for distinguishing between depressed and nondepressed patients with Parkinson's disease, along with reduced appetite and early morning awakening.

Aged↗

PubMed2025

Exploration of the genetic diversity of Avena Fatua L. (wild oat) through genotyping-by-sequencing and SDS-PAGE.

BACKGROUND: The consumption of oats has rapidly increased due to their exceptional nutritional value. However, concerns over genetic erosion have emerged as oat breeding programs rely on a highly limited genetic pool. This study aimed to expand the genetic diversity pool of oats by collecting wild oat (Avena fatua L.) populations in South Korea and assessing their genetic diversity and seed storage protein patterns. RESULTS: A total of 237 A. fatua individuals were collected in 2022 from eight regions in the southwestern coastal areas of South Korea. Genetic diversity and seed storage protein patterns were analyzed using genotyping-by-sequencing (GBS) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The GBS analysis identified 20,836 single-nucleotide polymorphisms (SNPs). An analysis of molecular variance (AMOVA) based on regional populations revealed that 40.9% of the genetic variation was attributed to differences among populations, while 59.1% was within populations, indicating high genetic differentiation within regional populations. Subsequent population structure analysis and discriminant analysis of principal components (DAPC) both stated the formation of two distinct genetic groups, with an AMOVA value of 70.9% between the groups, suggesting a high level of genetic variation. Pairwise FST analysis was conducted to compare the genetic differentiation between two populations, revealing that Jindo and Jangheung exhibited the highest level of genetic differentiation (FST = 0.795) among the geographic groups. Seed storage proteins were analyzed using SDS-PAGE, and the patterns were grouped using k-means clustering. A comparison between the groups based on protein patterns and those based on genetic variation revealed no significant correlation. CONCLUSION: This study provides data on the genetic diversity of A. fatua, a wild relative of cultivated oats, aimed at expanding the genetic pool of oats for future breeding programs. These findings are expected to be a foundational resource for oat breeding and genetic improvement efforts.

Genetic Variation↗

PubMed1986

A multivariate investigation of postpartum mood disturbance.

The interrelationships of 'blues' and later postpartum depression with a number of biochemical, medical, and psychosocial variables have been examined in 52 subjects. The two syndromes shared only an impressive association with a prior history of gynaecological problems. Puerperal 'blues' was characterised in addition by associations with primiparity, tearfulness during pregnancy, and reduced plasma total tryptophan in the early puerperium. Depressive symptomatology up to nine months postpartum was related to an excess of male births and to an altered pattern of decline of non-esterified fatty acids immediately postpartum. In each case, the 'risk' variables were statistically independent and combined linearly. Stepwise discriminant analysis successfully discriminated 'blues' and depression from their respective non-cases. 'Blues and postpartum depression were only weakly related and, apart from gynaecological history, each was associated with separate and independent causative factors.

Adolescent↗

PubMed2006

Understanding exercise behavior among Korean adults: a test of the transtheoretical model.

The purpose of this study was to examine the theorized association of Transtheoretical Model (TTM) of behavior change constructs by stage of change for exercise behavior among Korean adults. A total of 1,335 Korean adults were recruited and surveyed from the Nowon district, geographically located in northern Seoul. Four Korean-version questionnaires were used to identify the stage of exercise behavior and psychological attributes of adolescents. Data were analyzed by frequency analysis, MANOVA, correlation analysis, and discriminant analysis. Multivariate F tests indicated that behavioral and cognitive processes of change, exercise efficacy, and pros differentiated participants across the stages of exercise behavior. Furthermore, the findings revealed that adults' exercise behavior was significantly correlated with the TTM constructs and that overall classification accuracy across the stages of change was 50.6%. This study supports the internal and external validity of the TTM for explaining exercise behavior.

Adult↗

PubMed2004

Empirical study on mutual fund objective classification.

Mutual funds are usually classified on the basis of their objectives. If the activities of mutual funds are consistent with their stated objectives, investors may look at the latter as signals of their risks and incomes. This work analyzes mutual fund objective classification in China by statistical methods of distance analysis and discriminant analysis; and examines whether the stated investment objectives of mutual funds adequately represent their attributes to investors. That is, if mutual funds adhere to their stated objectives, attributes must be heterogeneous between investment objective groups and homogeneous within them. Our conclusion is to some degree, the group of optimized exponential funds is heterogeneous to other groups. As a whole, there exist no significant differences between different objective groups; and 50% of mutual funds are not consistent with their objective groups.

Journal Article↗

PubMed2001

Antiatherogenic mitochondrial genotype in patients with type 2 diabetes.

OBJECTIVE: To evaluate the significance of a longevity-associated mitochondrial genotype (Mt5178A) derived from a C --> A transversion at nucleotide position 5178 of mitochondrial DNA, which causes a Leu-to-Met substitution within the NADH dehydrogenase subunit 2 gene, in type 2 diabetic subjects. RESEARCH DESIGN AND METHODS: Mt5178 typing was done by polymerase chain reaction-restriction fragment-length polymorphism with the restriction enzyme AluI in 1,148 type 2 diabetic Japanese subjects, and the results were compared with the clinical characteristics. Then, the association of Mt5178 type with early atherosclerotic changes of the bilateral carotid arteries on ultrasonography was assessed in 412 diabetic subjects randomly selected from the original 1,148 type 2 diabetic subjects, while maintaining the same frequency of Mt5178A and Mt5178C. RESULTS: The frequency of Mt5178A in the type 2 diabetic subjects (454 of 1,148; 40%) was not different from that previously found in healthy blood donors (114 of 252; 45%). Clinical characteristics regarding diabetes were not significantly different between the Mt5178A group (n = 454) and the Mt5178C group (n = 694). However, the mean intima-media thickness (IMT) at six sites in the bilateral carotid arteries was significantly smaller in the Mrt5178A group than in the Mt5178C group (0.906 +/- 0.018 vs. 0.995 +/- 0.021 mm, mean +/- SEM, P = 0.022), and the Mt5178 type was significantly correlated with both the mean IMT and the presence of plaque on multiple regression analysis and discriminant analysis. CONCLUSIONS: The Mt5178A genotype may be unrelated to the etiology of type 2 diabetes. However, Mt5178A seems to have an antiatherogenic effect, at least in type 2 diabetic individuals.

Adult↗

PubMed1992

Differentiation of fear, anger, and joy.

The purpose of the present study was to identify the physiological characteristics corresponding to three affects (fear, anger, and joy), which were elicited through real situations in a laboratory. The subjects were asked to rate their psychological responses using the Affect Rating Scales for each affective situation. Physiological indices (diastolic and systolic blood pressures, heart rate, respiration rate and frequency of galvanic skin response) were measured. The subjects' affects can be characterized by two functions obtained through discriminant analysis. One discriminant function separated positive from negative affects; the other set apart anger from the remaining affects.

Adolescent↗

PubMed1979

Comparison of methods of predicting burn mortality.

Recent suggestions that patients "hopelessly burned" be permitted to die peacefully have refocused attention on the accuracy of different methods of predicting whether an individual burn patient will survive. The purpose of this presentation is to compare the accuracy of mortality predictions based upon four different statistical methods: (1) Baux's rule which adds the patient's age in years to the percentage of his body surface area burned--the original assertion was that values over 75 meant a very poor prognosis. (2) probit analysis, (3) discriminant analysis, and (4) logistic risk function analysis. Each of these methods was applied to data for over three thousand consecutive admissions to St. Mary's Hospital Burn Center in Milwaukee, Wisconsin. This data base and the four statistical models are described. Mortality predictions derived from the four models are compared, and some observations are made concerning the selection of an appropriate model for predicting burn mortality.

Adolescent↗