Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Fitting”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 541 records · Page 30Linked to original sources

Photokeratoscopy in the fitting of soft contact lenses.

Our ultimate goal is to develop a photokeratoscopic system that will enable the fitter to select an initial lens of the proper design and power to fit a given eye and with reasonable assurance that further fitting will rarely be required. Our studies in this direction have carried us through to a prefitting screening system for the Bausch and Lomb Soflens that greatly increases the probability of successful fitting (and which demonstrates the importance of corneal shape in the successful fit of this lens) to a highly promising experimental system that is applicable to larger lenses with spherical base curves. The development of this computer-assisted fitting system is highly desirable. It will make the fitting a much simpler and efficient process with much less trauma to the eye and a marked reduction in the risk of accidental infection than with trial lens fitting. But, a second desirable effect that is not readily apparent is the use of the computer to drive fabrication equipment to manufacture lenses on a custom-fit basis to obtain the maximum in physiological tolerance that these lenses are capable of delivering. In either case, the patient is the ultimate beneficiary and that should always be our major goal.

Adolescent↗

Ethanol pharmacokinetics in white women: nonlinear model fitting versus zero-order elimination analyses.

BACKGROUND: Studies have shown repeatedly that ethanol pharmacokinetics are not linear, yet most researchers still determine ethanol elimination by linear, zero-order kinetics. The goals of the present work were to: (1) fit four nonlinear pharmacokinetic models to mean breath alcohol concentration (BrAC)-time data of 27 women and determine the best-fit model; (2) fit the determined best-fit model to individual BrAC data and estimate the pharmacokinetic parameters; and (3) compare the method of nonlinear model fitting with the classical zero-order elimination method and determine in which cases the classical approach is justified. METHODS: Twenty-seven healthy white women ingested four drinks (total of 0.67 g x kg(-1)) of ethanol on two test days. Approximately 24 breath ethanol samples (for pharmacokinetic analyses) and one blood sample (for hormonal markers) were taken per day. Pharmacokinetic model evaluation was based on the coefficient of variation, the weighted residual sum of squares, and the sequence of the weighted residuals. Because hormonal changes across the menstrual cycle did not significantly influence ethanol pharmacokinetics, data from the two test days were pooled. RESULTS: The best-fit model was a one-compartment open model with first-order absorption and sequential first-order elimination, followed by Michaelis-Menten elimination kinetics. Fitting this model to the individual BrAC data yielded mean ka = 0.062 hr(-1), Vd = 0.457 L x kg(-1), ke = 0.011 hr(-1), Vmax = 0.136 g x L(-1) x hr(-1), and Km = 0.096 g x L(-1). For the classical analyses, mean time to peak BrAC = 1.83 hr, disappearance rate = 0.179 g x L(-1) x hr(-1), and area under the blood ethanol-time curve (AUC) = 2.884 g x L(-1) x hr. Correlational analyses showed that more frequent drinkers eliminated ethanol significantly faster and reached significantly lower AUC than less frequent drinkers. CONCLUSIONS: After multiple dose ingestion in white women, classical zero-order elimination analyses can be applied only to a limited portion of the descending BrAC-time curve. They seem justified and practical from 0.5 hr after peak BrAC until BrAC reaches 0.2 g x L(-1). To describe ethanol pharmacokinetics across the entire BrAC-time curve, however, sophisticated nonlinear model fitting is required.

Adult↗

Environment-dependent performance and fitness of Iris brevicaulis, I. fulva (Iridaceae), and hybrids.

We tested the relative fitness of two Louisiana Iris species (Iris brevicaulis and I. fulva) and their first-generation backcross hybrids in three experimental watering treatments: dry, field capacity, and flooded. Leaf area expansion rate, gas exchange (A(max), g(s), c(i)), and biomass at final harvest were measured for each species and hybrid class in all three environmental treatments. Fitness (based on total biomass) of the four genotypic classes differed significantly with environment. All genotypic classes performed most poorly in the dry treatment. The fitness ranking of genotypic class also changed across environments (significant genotypic class by treatment interaction) with hybrid genotype fitness shifting relative to parental genotypes. Integrating over all treatments, backcrosses to I. fulva showed the lowest fitness, whereas backcrosses to I. brevicaulis outperformed I. fulva. The differences in fitness were apparently achieved by a combination of differences in photosynthesis and allocation. In this system, hybrids are not necessarily less fit than their parents, and the relationship between hybrid and parental fitness is influenced by environmental conditions, lending support to the Hybrid Novelty model of hybrid zone evolution.

Journal Article↗

Moral value transfer from regulatory fit: what feels right is right and what feels wrong is wrong.

People experience regulatory fit (E. T. Higgins, 2000) when the strategic manner of their goal pursuit suits their regulatory orientation, and this regulatory fit feels right. Fit violation feels wrong. Four studies tested the proposal that experiences of fit can transfer to moral evaluations. The authors examined transfer of feeling wrong from fit violation by having participants in a promotion or prevention focus recall transgressions of commission or omission (Studies 1 and 2). Both studies found that when the type of transgression was a fit violation, participants expressed more guilt. Studies 3 and 4 examined transfer of feeling right from regulatory fit. Participants evaluated conflict resolutions (Study 3) and public policies (Study 4) as more right when the means pursued had fit.

Analysis of Variance↗

The genetic basis of adaptive population differentiation: a quantitative trait locus analysis of fitness traits in two wild barley populations from contrasting habitats.

We used a quantitative trait locus (QTL) approach to study the genetic basis of population differentiation in wild barley, Hordeum spontaneum. Several ecotypes are recognized in this model species, and population genetic studies and reciprocal transplant experiments have indicated the role of local adaptation in shaping population differences. We derived a mapping population from a cross between a coastal Mediterranean population and a steppe inland population from Israel and assessed F3 progeny fitness in the natural growing environments of the two parental populations. Dilution of the local gene pool, estimated as the proportion of native alleles at 96 marker loci in the recombinant lines, negatively affected fitness traits at both sites. QTLs for fitness traits tended to differ in the magnitude but not in the direction of their effects across sites, with beneficial alleles generally conferring a greater fitness advantage at their native site. Several QTLs showed fitness effects at one site only, but no opposite selection on individual QTLs was observed across the sites. In a common-garden experiment, we explored the hypothesis that the two populations have adapted to divergent nutrient availabilities. In the different nutrient environments of this experiment, but not under field conditions, fitness of the F3 progeny lines increased with the number of heterozygous marker loci. Comparison of QTL-effects that underlie genotype x nutrient interaction in the common-garden experiment and genotype x site interaction in the field suggested that population differentiation at the field sites may have been driven by divergent nutrient availabilities to a limited extent. Also in this experiment no QTLs were observed with opposite fitness effects in contrasting environments. Our data are consistent with the view that adaptive differentiation can be based on selection on multiple traits changing gradually along ecological gradients. This can occur without QTLs showing opposite fitness effects in the different environments, that is, in the absence of genetic trade-offs in performance between environments.

Adaptation, Biological↗

Clinical evaluation of fitting presbyopic patients with contact lenses.

This clinical investigation was performed to determine the success of using a system designed as a flow chart to fit presbyopic patients with contact lenses. The value of this type of system is to provide practitioners with a simple step-by-step approach to fitting presbyopic patients and reducing the costs of several trial fitting sets. Patients were fit with monovision, simultaneous vision bifocal, alternating vision bifocal or diffractive bifocal contact lenses. The patients were fit first with monovision, and, if unsuccessful with this or any of the above lens designs, they proceeded to the next stage. Stage 2 used the simultaneous lens design, Stage 3 the alternating lens design and Stage 4 the diffractive lens design. Of the 22 patients enrolled in the study, 17 (77.3 percent) were successful through Stage 3 and 18 (81.8 percent) were successful through Stage 4. The first three stages are those proposed by Bausch & Lomb as the Presbyopic Fitting System. The Presbyopic Fitting System was found to be simple to follow and successful in fitting presbyopic patients.

Adult↗

Fitness and genetic architecture of parent and hybrid willows in common gardens.

Models of hybrid zone dynamics incorporate different patterns of hybrid fitness relative to parental species fitness. An important but understudied source of variation underlying these fitness differences is the environment. We investigated the performance of two willow species and their F1, F2, and backcross hybrids using a common-garden experiment with six replicated gardens that differed in soil moisture. Aboveground biomass, catkin production, seed production per catkin, and seed germination rate were significantly different among genetic classes. For aboveground biomass and catkin production, hybrids generally had intermediate or inferior performance compared to parent species. Salix eriocephala had the highest performance for all performance measures, but in two gardens F, plants had superior or equal performance for aboveground biomass and female catkin production. Salix eriocephala and backcrosses to S. eriocephala had the highest numbers of filled seeds per catkin and the highest estimates of total fitness in all gardens. Measures of filled seeds per catkin and germination rate tend to support the model of endogenous hybrid unfitness, and these two measures had major effects on estimates of total seed production per catkin. We also estimated how the two willow species differ genetically in these fitness measures using line cross analysis. We found a complex genetic architecture underlying the fitness differences between species that involved additive, dominance, and epistatic genetic effects for all fitness measures. The environment was important in the expression of these genetic differences, because the type of epistasis differed among the gardens for above-ground biomass and for female catkin production. These findings suggest that fine-scale environmental variation can have a significant impact on hybrid fitness in hybrid zones where parents and hybrids are widely interspersed.

Ecosystem↗

A comparison between nomogram vs. trial fitting of rigid gas permeable contact lenses.

To determine the differences between prescribing a trial fitted vs. nomogram (System 10) selected rigid gas permeable contact lens, 42 subjects were fit with one lens design on one eye and the other lens design on the opposite eye. Subjective responses for comfort and vision, objective signs of central corneal clouding, conjunctival injection, post keratometry readings, 3-9 staining, over-refraction, post refraction and lens position were ranked and assigned to success levels for each eye. Subjects were evaluated at 1 week, 1 month, and 3 months. The first fit success rates were 92 percent for the trial fit and 86 percent for the nomogram fit. The trial fit lens attained significantly better outcomes in individual categories of comfort and over-refraction. It was noted that the lens diameters differed significantly and a large percentage of both types of lenses benefited from a slight blend and edge modification. Although trial fitting remains the method of highest success, nomogram fitting (using System 10) appears consistent enough to consider it an option for certain practice situations.

Adolescent↗

Distribution of fitness effects caused by random insertion mutations in Escherichia coli.

Very little is known about the distribution of mutational effects on organismal fitness, despite the fundamental importance of this information for the study of evolution. This lack of information reflects the fact that it is generally difficult to quantify the dynamic effects of mutation and natural selection using only static distributions of allele frequencies. In this study, we took a direct approach to measuring the effects of mutations on fitness. We used transposon-mutagenesis to create 226 mutant clones of Escherichia coli. Each mutant clone carried a single random insertion of a derivative of Tn10. All 226 mutants were independently derived from the same progenitor clone, which was obtained from a population that had evolved in a constant laboratory environment for 10,000 generations. We then performed competition experiments to measure the effect of each mutation on fitness relative to a common competitor. At least 80% of the mutations had a significant negative effect on fitness, whereas none of the mutations had a significant positive effect. The mutations reduced fitness by about 3%, on average, but the distribution of fitness effects was highly skewed and had a long, flat tail. A compound distribution, which includes both gamma and uniform components, provided an excellent fit to the observed fitness values.

Biological Evolution↗

Cardiorespiratory fitness and body mass index as predictors of cardiovascular disease mortality among men with diabetes.

BACKGROUND: Questions remain as to whether higher levels of cardiorespiratory fitness, a measure of regular physical activity, are associated with lower risk of cardiovascular disease (CVD) mortality in overweight and obese individuals with diabetes. Our objective was to quantify the independent and joint relations of cardiorespiratory fitness (hereafter, fitness) and body mass index (BMI; calculated as weight in kilograms divided by the square of height in meters) with CVD mortality in men with diabetes. METHODS: This study was conducted using prospective observational data from the Aerobics Center Longitudinal Study. Study participants comprised 2316 men with no history of stroke or myocardial infarction and who were diagnosed as having diabetes (mean [SD] age, 50 [10] years); had a medical examination, including a maximal exercise test during 1970 to 1997 with mortality surveillance to December 31, 1998; and had a BMI of 18.5 or greater and less than 35.0. The main outcome measure was CVD mortality across levels of fitness with stratification by BMI. RESULTS: We identified 179 CVD deaths during a mean (SD) follow-up of 15.9 (7.9) years and 36,710 man-years of exposure. In a model containing age, examination year, fasting glucose level, systolic blood pressure, parental history of premature CVD, total cholesterol level, cigarette smoking, abnormal resting, and exercise electrocardiograms, a significantly higher adjusted risk of mortality was observed in men with a low fitness level who were normal weight (hazard ratio, 2.7 [95% confidence interval, 1.3-5.7]), overweight (hazard ratio, 2.7 [95% confidence interval, 1.4-5.1]), and class 1 obese (hazard ratio, 2.8 [95% confidence interval, 1.4-5.1]) compared with normal weight men with a high fitness level. CONCLUSION: In this cohort of men with diabetes, low fitness level was associated with increased risk of CVD mortality within normal weight, overweight, and class 1 obese weight categories.

Body Mass Index↗

Cardiorespiratory fitness levels among US youth 12 to 19 years of age: findings from the 1999-2002 National Health and Nutrition Examination Survey.

OBJECTIVES: To assess cardiorespiratory fitness levels in youth aged 12 to 19 years and to examine associations between fitness and age, sex, race/ethnicity, and self-reported physical activity in this age group. DESIGN: Cross-sectional study. SETTING: The National Health and Nutrition Examination Survey's mobile examination center, throughout the United States from 1999-2002. PARTICIPANTS: A representative sample of 4732 youth aged 12 to 19 years was examined; 3287 completed the treadmill test and were included in the analysis. The National Center for Health Statistics conducted the survey. Main Exposures Age, sex, race/ethnicity, weight status, self-reported physical activity, and television viewing. Main Outcome Measure Estimated maximal oxygen uptake (VO2max) determined by a submaximal treadmill exercise test. RESULTS: Estimated VO2max (mL.kg(-1) . min(-1)) was higher in males (mean +/- SE, 46.4 +/- 0.4) than in females (mean +/- SE, 38.7 +/- 0.3) but did not differ across race/ethnicity groups. Among males, older participants had higher VO2max values, while in females, younger participants had higher values. For both males and females, those in the normal weight group had higher fitness levels than those in the at risk for overweight and overweight groups. Approximately one third of both males and females failed to meet recommended standards for cardiorespiratory fitness. CONCLUSIONS: In US youth, cardiorespiratory fitness is lower in males and females who are overweight than in those of normal weight, but fitness is not related to race/ethnicity. Youth who have low levels of physical activity and high levels of sedentary behavior are also more likely to have lower cardiorespiratory fitness.

Adolescent↗

Physical fitness training for stroke patients.

BACKGROUND: Stroke patients have impaired physical fitness and this may exacerbate their disability. It is not known whether improving physical fitness after stroke reduces disability. OBJECTIVES: The primary aims of the review were to establish whether physical fitness training reduces death, dependence and disability after stroke. The secondary aims of the review included an investigation of the effects of fitness training on secondary outcome measures (including, physical fitness, mobility, physical function, health and quality of life, mood and the incidence of adverse events). SEARCH STRATEGY: We searched the Cochrane Stroke Group Trials Register (June 2003). In addition, the following electronic databases were searched: Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2002 Issue 4), MEDLINE (1966 to December 2002), EMBASE (1980 to December 2002), CINAHL (1982 to December 2002), SPORTDiscus (1949 to December 2002), Science Citation Index Expanded (1981 to December 2002), Web of Science Proceedings (1982 to December 2002), Physiotherapy Evidence Database (December 2002), REHABDATA (1956 to December 2002) and Index to UK Theses (1970 to December 2002). We hand searched relevant journals and conference proceedings and screened reference lists. To identify unpublished and ongoing trials we searched trials directories and contacted experts in the field. SELECTION CRITERIA: Randomised controlled trials were included when an intervention represented a clear attempt to improve either muscle strength and/or cardiorespiratory fitness, and whose control groups comprised either usual care or a non-exercise intervention. DATA COLLECTION AND ANALYSIS: Data from eligible studies were independently extracted by two reviewers. The primary outcome measures were death, disability and dependence. The lack of common outcome measures prevented some of the intended analysis. MAIN RESULTS: A total of twelve trials were included in the review. No trials reported death and dependence data. Two small trials reporting disability showed no evidence of benefit. The remaining available secondary outcome data suggest that cardiorespiratory training improves walking ability (mobility). Observed benefits appear to be associated with specific or 'task-related' training. REVIEWER'S CONCLUSIONS: There are few data available to guide clinical practice at present with regard to fitness training interventions after stroke. More general research is needed to explore the efficacy and feasibility of training, particularly soon after stroke. In addition more specific studies are required to explore the effect of content and type of training. Further research will require careful planning to address a number of issues peculiar to this type of intervention.

Exercise Therapy↗

The protective effect of good physical fitness when young on the risk of impaired glucose tolerance when old.

BACKGROUND: The role of physical activity or fitness on preventing impaired glucose tolerance (IGT) has not been widely investigated. The present case-control study examined the relationship between the occurrence of IGT in men in their 50s and the level of their physical fitness while in their 30s. METHODS: The subjects consisted of 38 male Japan Self-Defense Forces officials in their 50s who had IGT, as diagnosed by the 75-g oral glucose tolerance test, and 60 control individuals. Nine diabetics were included in the IGT cases. As an indicator of physical fitness between the ages of 30 and 39 years, we selected the best time recorded for each individual during that decade of life for the 1,500-m physical fitness test run. We calculated the odds ratio for IGT in relation to selected risk factors (including physical fitness), and a logistic regression analysis was used to adjust for possible confounding variables. RESULTS: The odds ratio (95% confidence interval, P value) for IGT with physical fitness in their 30s was 0.25 (0.11-0.58, P < 0.05). With adjustment for a parental history of diabetes and body mass index in both their 30s and their 50s, the odds ratio was 0.31 (0.11-0.86, P < 0.05). CONCLUSIONS: We concluded that the occurrence of IGT, including diabetes, in men in their 50s can be reduced by maintaining a high level of physical fitness while in their 30s.

Adult↗

Development and initial validation of the Effort Sense Rating Scale (ESRS): a self-perceived index of physical fitness.

BACKGROUND: The Effort Sense Rating Scale is a non invasive, easy to administer, self-assessment device for deriving an index of physical fitness comprising only aerobic and anaerobic power components. The scale originates from the notion that people who have experienced varying degrees of effort doing "everyday" tasks can accurately estimate the exertion required in fairly common, physically demanding "situations" when provided with an appropriate perceptual frame-of-reference. Estimations elicited in this way can be scaled and used to categorize fitness level. This article reports an initial validity study. Further development of this technique is in progress. SAMPLE: Forty volunteers from a university community, mainly students (17 women and 23 men), completed ESRS twice and then underwent submaximal aerobic (cycle ergometry: YMCA protocol) and anaerobic power (Wingate protocol) assessments. RESULTS: Nonparametric correlation coefficients between the Effort Sense Rating Scale and the aerobic power were r(s) = 0.47 (P < 0.05) and anaerobic power r(s) = 0.62 (P < 0.05). Interpreted at the category level there was 77.5% agreement between ESRS indices and category levels for measured fitness components. Readministration of the Effort Sense Rating Scale after 14 days prior to physical assessments showed 100% consistency in choice of rating items with some changes in assigned values (r(s) = 0.86, P < 0.01). CONCLUSIONS: Modifications to the equivalence and selection of fitness elements and wording of the effort-demanding "scenarios," the discriminative level of the fitness categories, and broadening the size and composition of the validation sample are required to further enhance the veracity of the scale. Appropriately tuned, this perception-based approach to self-assessment of physical fitness can provide a low-cost, meaningful device for baseline setting and progress monitoring by people either entering or continuing with an exercise program for health-related fitness purposes.

Activities of Daily Living↗

Physical fitness and sport activity of children and adolescents: methodological aspects of a regional survey.

Measurement of physical fitness and physical activity in children and adolescents raise a lot of methodological issues, explaining the scarcity of surveys in European countries and in Switzerland. This article exposes the design and the methods used in a survey on physical fitness, physical activity and health conducted in a region of Switzerland, and discuss the choice of the instruments and the quality control procedure selected to measure physical activity and physical fitness. The survey was conducted in a sample of 3540 students 9-19 years-old and included a battery of physical fitness tests, anthropometrics measurements and a self-report questionnaire on physical activity, sports activity and life styles. An ancillary study in a sub sample assessed daily physical activity with a pedometer, dietary intake with a 3-day dietary record, serum lipids and nutritional status. Some results are displayed as example. Quality control techniques are exposed and the choice of the instrument to assess physical fitness, physical activity, sports, and dietary intake are discussed. Local reference tables are now available for fitness tests and the practicability of fitness testing has been demonstrated in physical education. The research process has induced the sensitisation of schools toward health promotion through physical activity.

Adolescent↗

Fitness changes in an Australian Antarctic expedition.

Serial fitness testing using a cycle ergometer and a submaximal work-load technique was performed monthly on 22 expeditioners at Davis Station, Antarctica, during the period February 1982 to January 1983. The results showed a linear increase in fitness in the group over the 12 month study period, including the winter period when outdoor activities were limited. The regression equation for fitness (measured as maximum oxygen uptake) was VO2max (ml . min-1 . kg-1) = 43.96 + 0.631 (time) where time is the month number from 1 through to 12. The correlation coefficient of the regression line representing fitness plotted against time in months was 0.918 (p less than 0.001). It is evident that indoor station activities and limited outdoor activities were more than adequate to maintain physical fitness in the winter period. Pre-departure fitness assessment for expeditioners is suggested. As fitness was lowest on arrival in Antarctica yet station workloads heaviest at this time, physical training prior to arrival in Antarctica is recommended for future expeditions.

Adult↗

A physical fitness model of older adults.

Physical fitness for young people is viewed as a multidimensional construct, in that it consists of specific components such as strength, mobility, balance, flexibility, and stamina. This study examined whether this structure underlying physical fitness is also relevant to older adults. A 10-item performance test, which was assumed to assess six components of physical fitness, was administered to 69 healthy volunteers ranging in age from 61 to 83 years. A covariance structure model was applied to the test data: the second-order factor was Physical Fitness, and the first-order factors were Strength, Walking, Balance, Flexibility, Stamina, and Manual Speed which were assumed to be measured based on the ten observed variables. Goodness-of-fit index (GFI) of the model was acceptable (GFI = 0.93). While four factors relating to basic motor performances (Strength, Walking, Balance, and Manual Speed) had loadings more than 0.62 to Physical Fitness, Flexibility and Stamina had less than 0.35. It was suggested for elderly people that strength, mobility, balance, and speed components of physical fitness were highly correlated and explainable by a single factor, while flexibility and cardiorespiratory endurance were to be measured by use of specific measures.

Aged↗

Adiposity, physical fitness and incident diabetes: the physical activity longitudinal study.

AIMS/HYPOTHESIS: The purpose of this study was to investigate the relationships among adiposity, physical activity, physical fitness and the development of diabetes in a diverse sample of Canadians. METHODS: The sample included 1,543 adults (709 men and 834 women) from the Canadian Physical Activity Longitudinal Study who were free of diabetes at baseline (1988). Several indicators of adiposity (BMI, waist circumference, WHR, sum of skinfold thicknesses), musculoskeletal fitness (sit-ups, push-ups, grip strength, trunk flexibility), cardiorespiratory fitness (maximal metabolic equivalents [METs]) and leisure-time physical activity levels were measured at baseline. Participants were followed until 2002-2004 for the ascertainment of new cases of diabetes. RESULTS: The 15.5-year cumulative incidence of diabetes was 5.0% (5.2% in men, 4.9% in women). Adiposity and physical fitness, but not physical activity, were significant predictors of diabetes after adjustment for age, sex and several covariates. For each standard deviation of the indicators of adiposity, the risk of diabetes was 99-194% higher. Conversely, the risk was 70 and 61% lower for each standard deviation of maximal METs and composite musculoskeletal fitness score, respectively. Receiver operating characteristic curve analyses confirmed that neither adiposity nor physical fitness provided a superior prediction of incident diabetes. CONCLUSIONS/INTERPRETATION: Adiposity and physical fitness were both important predictors of the development of diabetes in this cohort of Canadians.

Adipose Tissue↗