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Schooling, occupational motivation, and personality as related to success in paramedical training.

Measures of prior school experience, motivation for working in a health care job, and personality were evaluated as potential predictors of success in Navy paramedical training. When, by multiple regression procedures, years of school completed, numbers of suspensions or expulsions from school, occupational motivation, and Comrey personality scale scores were combined with an aptitude measure that is used for guiding recruits into paramedical training, the cross-validity for predicting training completion was significantly increased (P less than 0.001) from 0.40 to 0.50. Practical means for applying these measures to the screening of candidates for paramedical training were developed. Results of the evaluation suggest that guiding people into jobs that they neither prefer nor perceive as congruent with their abilities and interests can significantly reduce the chances for occupational success.

Achievement↗

PubMed1994

Neural-network classification of normal and Alzheimer's disease subjects using high-resolution and low-resolution PET cameras.

UNLABELLED: Neural-network classification methods were applied to studies of FDG-PET images of the brain acquired from a total of 77 "probable" Alzheimer's disease and 124 normal subjects at two different centers. METHODS: Classification performances, as determined by relative-operating-characteristic (ROC) analyses of cross-validation experiments, were measured for FDG PET images obtained with either a 15-mm FWHM PETT V or a 6-mm FWHM Scanditronix PC-1024-7B camera for various methods of data representation. Neural networks were trained to distinguish between normal and abnormal subjects on the basis of regional metabolic patterns. For both databases, classification performance could be improved by increasing the "resolution" of the representation (decreasing the region size) and by normalizing the regional metabolic values to the value of a reference region (occipital region). RESULTS: The optimal classification performance for Scanditronix data (ROC area = 0.95) was higher than that for PETT V data (ROC area = 0.87). Under Bayesian theory, the classification performance with Scanditronix data corresponded to an ability to change a pre-test probability of disease of 50% to a post-test probability of either 90% for a positive classification or 10% for a negative classification. CONCLUSION: This classification can be used to either strongly confirm or rule out the presence of abnormalities.

Aged↗

PubMed1994

Prognosis of rehabilitation outcome in head injury using the Disability Rating Scale.

In this correlational study, we investigated the prediction of functional status on discharge from head injury rehabilitation in 64 adults with traumatic closed head injury. Subjects were rated on Rappaport's Disability Rating Scale during rehabilitation to obtain the Disability Rating Score on admission to rehabilitation, recovery rate during the first month of rehabilitation, and discharge Disability Rating Score. Potential prognostic variables included demographic and social characteristics, severity of injury indicators, head injury deficits present on admission to rehabilitation, and initial Disability Rating Score, and recovery rate. Multiple regression analyses were performed to determine if discharge Disability Rating Score could be predicted from subsets of the potential prognostic variables. Significant contributions were made to the regression equations by initial Disability Rating Score, recovery rate, post-traumatic amnesia and cognitive deficits. A single multiple regression containing the four significant predictors retained initial Disability Rating Score and recovery rate as significant. The findings were cross-validated on a new sample of 30 head injury patients. Initial Disability Rating Score on admission to rehabilitation emerged as a useful predictor of rehabilitation outcome.

Adolescent↗

PubMed1993

Evaluation of laboratory data by conventional statistics and by three types of neural networks.

Sixty-three patients with lung (34 small-cell, 18 squamous, 11 adeno-) carcinomas and 43 patients with benign lung diseases were characterized with seven tumor markers: neuron-specific enolase (NSE); cancer antigens CA 19-9, CA 125, CA 15-3, and CA 50; carcinoembryonic antigen (CEA); and tissue polypeptide antigen. Diagnosis had been established by histological examination after surgery and used for classification. After vector transformation, the tumor marker data were fed into neural networks (NNs) based on three different types of learning algorithms: backpropagation (BP), competitive learning (CL), and Hopfield (H). For comparison, the data were evaluated with multivariate stepwise discriminant analysis (MVSDA). BP-NNs are equal to (NSE, CA 19-9, CEA) or better than (100% correct classification when using all seven markers) MVSDA in assigning the correct diagnosis to the patients. Cross-validation data yielded shrinkage effects ranging from 0% to 12.5%. Quality-control (QC) data were evaluated by traditional QC algorithms and compared with the results obtained by a BP-NN. The results show that the BP-NNs could only partly fulfill the tasks of three QC algorithms regarding the violation of static borders but gave good results with respect to dynamic changes.

Biomarkers, Tumor↗

PubMed1993

Factors which discriminate rural and urban family physicians practicing in South Carolina.

A sample of 28 rural and urban private practicing family physicians was compared on a number of attitudes and practice characteristics based on results from a mailed questionnaire. Results cross-validated previous findings and provided new ones. A number of self-report discriminators are discussed to better predict which physicians will locate in rural areas.

Adult↗

PubMed1993

Radioimmunological analysis of ethinylestradiol in human serum. Validation of the method and comparison with a gas chromatographic/mass spectrometric assay.

The majority of combination oral contraceptives contain ethinylestradiol (EE2, CAS 57-63-6) as estrogenic component at doses between 50 and 20 micrograms/unit. Since the concentrations of EE2 in the serum of women under oral contraceptive (OC) therapy are in the lower pg-range, highly sensitive and specific analytical methods are required. Radioimmunoassay (RIA) has been the method of choice, but evidence of specificity in the presence of the coadministered progestogens and their metabolites has not always been provided. The present study compares two radioimmunological methods, which use the same antiserum but different sample volumes and standard curves (extracted vs. non-extracted), with a newly developed gas chromatographic/mass spectrometric (GC/MS) method, in order to cross-validate the methods. For that purpose, 51 serum samples obtained from women who had been taking two different combination oral contraceptives were analysed independently by all three methods. The specificity of the antiserum was further examined by submitting ex vivo serum samples obtained from OC-users to a combination of high pressure liquid chromatography (HPLC) and RIA. The results obtained by the three methods were very similar and correlation coefficients (r) obtained from linear regression analysis were about 0.7. There was no interference from the coadministered progestins on the analysis of EE2 as carried out by the three methods. There were no metabolites in the extracts of ex vivo serum samples which showed cross-reactivity with the antiserum used. Modifications of the radioimmunoassay procedure did not markedly affect the results of EE2 determination. If properly validated, radioimmunoassay can be used as an alternative to GC/MS in pharmacokinetic studies.

Chromatography, High Pressure Liquid↗

PubMed1993

Effect of stepping rate on energy costs during StairMaster exercise.

The responses to a self-selected stepping pattern (random) on a StairMaster 4000PT were compared with those obtained in response to the rates established by the manufacturer (cadence) in men (N = 14) and women (N = 14). During the random test the subjects stepped at their own natural, self-selected rate and distance. In cadence trial the subjects were required to step in time with a metronome at a predetermined rates of 60, 77, 95, and 112 steps.min-1. Each trial consisted of four, 5-min continuous workloads during which HRs were recorded and expired air was analyzed using an automated open-circuit gas system each minute. All size dependent variables (i.e., VE and lO2.min-1) as well as relative VO2 (mlO2.kg-1.min-1) were significantly (P < 0.01) higher for the men across all stages and between methods. Although the random test produced slightly higher oxygen consumption values than the cadence trial, these differences were not significant (P > 0.05). The actual METs were significantly (P < 0.01) higher at all stages except at the lowest stepping rate for both methods compared with those estimated by the manufacturer. Equations were established to estimate actual MET costs: Men's METs = 2.675 + 0.935 (rate); women's METs = 2.934 + 0.817 (rate). Cross-validations of 0.975 and 0.957 were obtained on an additional group of men (N = 8) and women (N = 11), respectively.

Adult↗

PubMed1993

VO2max estimation from a submaximal 1-mile track jog for fit college-age individuals.

The primary purpose of this study was to develop a submaximal field test for the estimation of maximal oxygen uptake (VO2max) using a 1-mile track jog. A second purpose was to determine the accuracy of the 1.5-mile run in estimating VO2max for both male and female subjects. VO2max was measured in 149 relatively fit college students (males = 88, females = 61) 18-29 yr using a treadmill protocol (mean +/- SD; VO2max = 47.7 +/- 6.3 ml.kg-1 x min-1). Multiple regression analysis (N = 54) to estimate VO2max from the submaximal, steady-state 1-mile track jog yielded the following validation (V) model (r(adi) = 0.87, SEE = 3.0 ml.kg-1 x min-1): VO2max = 100.5 + 8.344* GENDER (0 = female; 1 = male) - 0.1636* BODY MASS (kg) - 1.438* JOG TIME (min.mile-1) - 0.1928* HEART RATE (bpm). To help ensure that a submaximal level of exertion was realized for the 1-mile track jog, elapsed jog time was restricted to > or = 8.0 min for males and > or = 9.0 min for females and exercise HR to < or = 180 bpm. Cross-validation (CV) of the 1-mile track jog comparing observed and estimated VO2max (N = 52) resulted in radj = 0.84, SEE = 3.1 ml.kg-1 x min-1. Multiple regression analysis (N = 50) to estimate VO2max from the 1.5-mile run (V:N = 49, radj = 0.90, SEE = 2.8 ml.kg-1 x min-1; CV: N = 47, radj = 0.82, SEE = 3.9 ml.kg-1 x min-1), used elapsed run time, body mass, and gender as independent variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Development of a submaximal treadmill jogging test for fit college-aged individuals.

The purpose of this study was to develop a single-stage submaximal treadmill jogging test for the estimation of maximal oxygen uptake (VO2max). VO2max was measured in 129 relatively fit individuals (males = 84, females = 45), 18-29 yr, using a maximal treadmill protocol (mean +/- SD; VO2max = 48.3 +/- 6.2 ml.kg-1 x min-1, range = 35.6 to 62.3 ml.kg-1 x min-1). The treadmill test required subjects to sustain a comfortable, submaximal jogging pace (4.3-7.5 mph; level grade) until a steady-state heart rate was achieved (approximately 3 min). To help ensure that a submaximal level of exertion was realized for the treadmill jogging test, treadmill speed and exercise HR criteria were established that restricted treadmill speed to < or = 7.5 mph for males and < or = 6.5 mph for females and steady-state exercise HR < or = 180 bpm. Multiple regression analysis (N = 66) to estimate VO2max from the treadmill jogging test yielded the following validation (V) model (r(adj) = 0.84, SEE = 3.2 ml.kg-1 x min-1): VO2max = 54.07 + 7.062 * GENDER (0 = female; 1 = male) - 0.1938 * WEIGHT (kg) + 4.47* SPEED (miles.h-1) - 0.1453 * HEART RATE (bpm). Cross-validation (CV) of the treadmill jogging test comparing observed and estimated VO2max (N = 63) resulted in r(adj) = 0.88, SEE = 3.1 ml.kg-1 x min-1. The results indicate that this submaximal single-stage treadmill jogging test based on multiple linear regression provides a valid and convenient method for estimating VO2max.

Adolescent↗

PubMed1995

Predictive accuracy of bioimpedance equations in estimating fat-free mass of Hispanic women.

This study assessed the predictive accuracy of previously published bioelectrical impedance analysis equations for estimating fat-free mass of young (20-39 yr) Hispanic women (N = 29). The reference method was hydrostatic weighing at residual lung volume. Body density was converted to percent body fat using the Siri equation. Resistance and reactance were measured with a Valhalla bioimpedance analyzer. The bioelectrical impedance analysis equations of Lohman, Rising, Stolarczyk, Segal, Gray, and Van Loan were cross-validated. There were significant correlations between criterion and predicted fat-free mass (r = 0.86-0.95) for all equations. The standard error of estimate for each equation was acceptable; however, the total error for the Stolarczyk (3.2 kg) and the Van Loan (4.6 kg) equations exceeded the recommended value (2.8 kg). For all equations, the difference between average criterion and predicted fat-free mass was significant (P < 0.05). However, the mean differences for the Lohman (0.8 kg), Segal (0.8 kg), and Gray (0.9 kg) equations were small. In conclusion, the Segal, Lohman, and Gray equations may have potential for assessing the body composition of healthy, acculturated, Hispanic women.

Acculturation↗

PubMed1995

Validity of skinfold equations for estimating body density in youth wrestlers.

The present investigation examined the validity of 16 skinfold equations for predicting body density (BD) in youth wrestlers (mean age +/- SD = 11.0 +/- 1.3 yr) by comparing the values to those obtained from underwater weighing. Forty-eight members of youth wrestling clubs (mean BD +/- SD = 1.0634 +/- 0.0125 g.cm-3) volunteered to serve as subjects. The statistical analyses included examination of the constant error (CE), standard error of estimate (SEE), correlation coefficient (r), and total error (TE). The results of this investigation indicated that all of the equations resulted in TE values that were > or = 0.0106 g.cm-3 (range = 0.0106-0.0229 g.cm-3) which corresponded to > or = 4.9% body fat. The TE values were too large to provide accurate estimates of body composition in the present sample of youth wrestlers. Future studies should use the CE values from the present investigation to adjust the intercepts of the skinfold equations in the present study and cross-validate the modified equations on young male athletes.

Body Composition↗

PubMed1995

[Body density assessment utilizing skinfold thickness and age in Japanese men].

A study was conducted to investigate the validity of skinfold-based prediction equations for body density (g/ml) by Nagamine and Suzuki (1964), and to formulate more convenient and more useful equations for predicting body density from skinfold and age in men. Subjects of the study were 257 healthy men aged 19-60 years in or near Nagasaki City. The regression equation for the dependent variable, body density, was determined by hydrostatic weighing. Independent variables included eight skinfolds, the sum of two skinfolds (triceps, subscapular), the sum of three skinfolds (triceps, subscapular, and abdominal), age, and body surface area. Skinfolds were measured with an Eiken-model skinfold caliper. Age (mean 33.1, range 19-60 yrs.), weight (mean 65.3, range 46.6-107.7 kg), height (mean 168.8, range 152.3-185.4 cm), and body density (mean 1.05874, range 1.00860-1.09020 g/ml) were also recorded. Percent body fat was calculated using the formula by Brozek et al. and ranged from 6.1% to 38.9%. Multiple correlation coefficients (MR) and standard error (SE) of 10 regression equations (A-J) for predicting body density in men were obtained. The best-fitting and the most convenient prediction equation for body density was equation-E.: body density = 1.09556-0.00062 x sum of three skinfolds (mm)-0.00028 x age (MR = 0.815 and SE = 0.0087 g/ml). The equation was cross-validated on a different sample of 45 men. The correlation coefficient between predicted and hydrostatically determined body density was 0.781 (p < 0.001). Equation-E (Tahara's equation) appears to be useful in body density analysis particularly when the subjects are Japanese men, aged 18-50 yrs, with percent body fat 10 to 30%.

Adult↗

PubMed1977

Interaction between consumers and providers of health services: new roles and their implications.

In the last few years, there has been an active effort in Italy to involve the population in solving health problems at the community level. This movement had its origin in the industrial setting, where workers succeeded in promoting legislation which gives them control over matters affecting their health. This experience lead to the development of a health education methodology based on the following principles: (a) the assessment of health needs must be based on the subjective experience of the people who have acquired knowledge and interest in health problems; (b) the evaluation of health needs by professionals serves to complement and integrate the assessment of needs as experienced by the community; (c) the self-diagnosis of the community -- in particular of homogenous community groups exposed to similar health risks and experiencing the same needs--and the diagnosis of the professionals must undergo cross-validation and be accepted by both parties; (d) on the basis of this mutual agreement, community health programmes should be planned and carried out jointly by the professionals and the people.

Community Participation↗

PubMed1996

A statistical model predicting the seizure threshold for right unilateral ECT in 106 patients.

Titration of the electroconvulsive therapy (ECT) stimulus to the patient's convulsive threshold is the only way to directly assess the patient's seizure threshold. This technique is presently practiced by 39% of ECT providers, according to a recent survey. Because multiple variables influence the seizure threshold in patients, multivariate statistical methods may provide a useful strategy to determine which variables exert the most influence on convulsive threshold. A multivariate ordinal logistic model of seizure threshold was developed on an experimental group of 66 consecutive patients undergoing titrated right unilateral (RUL) ECT for major depression. The accuracy of the model was cross-validated on a second group of 40 patients undergoing similar RUL ECT procedures. The final multivariate ordinal logistic regression model for the seizure threshold level (STL) was significant (Likelihood ratio chi 2 = 54.115; p < 0.0001:R2 = 0.313). Increasing age, African-American race, and longer inion-nasion distances (p < 0.06) predicted higher STL. Female gender was associated with a lower STL. The ability of the final model to accurately predict STL for the validation group was fair (pairwise correlation was 0.576; p < 0.001). The model did well for predicting lower STL, but fared poorly for higher STL. In conclusion, modeling STL may help establish the relative contribution of variables thought to be important to seizure threshold. However, STL models remain impractical for clinical applications in estimating seizure threshold at this time, and empirical stimulus titration should be used.

Adult↗

PubMed1995

Some positive effects of transcranial magnetic stimulation.

It is hoped that this survey conveys a sense of the many positive uses of focal and nonfocal MC stimulation already manifest within a decade of its introduction. As with other techniques of investigating brain function, MC stimulation has its relative advantages and disadvantages. The precision of defining the site of MC effects currently is inferior to that achieved with PET scanning, but the precision of timing of effects is superior, being on the order of milliseconds. Perhaps the special value of MC stimulation is in moving closer to specifying cause-effect relationships, through interference or facilitatory effects, than when techniques yielding more circumstantial evidence are used. However, it is the testing and cross-validation of the conclusions from the different modes of neuroscientific inquiry that we look to in synthesizing explanations of brain function.

Brain↗

PubMed1996

[Validation of the German version of the 20-item Toronto Alexithymia Scale in normal persons and psychiatric patients].

This paper describes the cross-validation of the German version of the 20-Item Toronto Alexithymia Scale (TAS-20) in normal adults (n = 306) as well as in a psychiatric inpatients sample (n = 101). The scale showed adequate estimates of internal consistency, split-half and test-retest reliability, and a three-factor structure comparable to that obtained for the English version of the TAS-20 which was found to be consistent with the main features of the alexithymia construct. Evidence of convergent validity of the German TAS-20 was demonstrated by significant positive correlations with conceptual related psychometric scales. The finding of significantly higher alexithymia scores in the psychiatric patients sample as compared to normal adults underlined the clinical validity of the German version of the TAS-20.

Adolescent↗

PubMed1996

A probabilistic classification system for predicting the cellular localization sites of proteins.

We have defined a simple model of classification which combines human provided expert knowledge with probabilistic reasoning. We have developed software to implement this model and have applied it to the problem of classifying proteins into their various cellular localization sites based on their amino acid sequences. Since our system requires no hand tuning to learn training data, we can now evaluate the prediction accuracy of protein localization sites by a more objective cross-validation method than earlier studies using production rule type expert systems. 336 E. coli proteins were classified into 8 classes with an accuracy of 81% while 1484 yeast proteins were classified into 10 classes with an accuracy of 55%. Additionally we report empirical results using three different strategies for handling continuously valued variables in our probabilistic reasoning system.

Cells↗

PubMed1996

A generalized hidden Markov model for the recognition of human genes in DNA.

We present a statistical model of genes in DNA. A Generalized Hidden Markov Model (GHMM) provides the framework for describing the grammar of a legal parse of a DNA sequence (Stormo & Haussler 1994). Probabilities are assigned to transitions between states in the GHMM and to the generation of each nucleotide base given a particular state. Machine learning techniques are applied to optimize these probabilities using a standardized training set. Given a new candidate sequence, the best parse is deduced from the model using a dynamic programming algorithm to identify the path through the model with maximum probability. The GHMM is flexible and modular, so new sensors and additional states can be inserted easily. In addition, it provides simple solutions for integrating cardinality constraints, reading frame constraints, "indels", and homology searching. The description and results of an implementation of such a gene-finding model, called Genie, is presented. The exon sensor is a codon frequency model conditioned on windowed nucleotide frequency and the preceding codon. Two neural networks are used, as in (Brunak, Engelbrecht, & Knudsen 1991), for splice site prediction. We show that this simple model performs quite well. For a cross-validated standard test set of 304 genes [ftp:@www-hgc.lbl.gov/pub/genesets] in human DNA, our gene-finding system identified up to 85% of protein-coding bases correctly with a specificity of 80%. 58% of exons were exactly identified with a specificity of 51%. Genie is shown to perform favorably compared with several other gene-finding systems.

Chromosomes, Human↗