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PubMed1991

Relationships of anxiety scores to screening and training status of air traffic controllers.

The present study assessed the relationship between anxiety, as measured by the State-Trait Personality Inventory (STPI), and success of post-strike air traffic control specialist (ATCS) trainees at the FAA Academy and during field training. The STPI was administered to students who entered the FAA Academy between June 1984 and September 1985. Academy test scores were obtained for 1,790 students in the en route option. Criterion data included the field training status of the Academy graduates as of July 1988. Statistical analyses determined the relationships between ATCS student scores on the STPI measures and a) normative data and b) Academy screening and field training results. ATCS students reported significantly lower state (current level) and trait (proneness) levels of anxiety than did either college students or military recruits. Trainees who had relatively high scores (for ATCSs) on a combined index of the trait and state measures of anxiety exhibited significantly higher a) percentages of Academy failures/withdrawals, b) percentages of option switches in the field, and c) overall field attrition, than did trainees with low scores. Results support the operation of some personality-related self-selection among ATCS applicants regarding anxiety and the importance of this low anxiety characteristic for ATCS job success.

Aerospace Medicine↗

PubMed1991

Segmental contributions to total body momentum in sit-to-stand.

In a previous investigation, we reported that the maximum linear momentum of the body center of mass (CM) during a sit-to-stand task showed a relative invariance in the horizontal vs the vertical direction of motion as the speed of ascent increased from natural to fast. The present study investigated the segmental origin of this directionally specific difference by examining the linear momentum of the shank, thigh, and head-arm-trunk segments for ten healthy young adults at slow, natural, and fast self-selected speeds. Findings indicated that the head-arm-trunk was the major contributor to the horizontal maximum linear momentum of the CM and accounted for the relative invariance in its magnitude. In contrast, the thigh was the major contributor to the vertical maximum linear momentum of the CM and was responsible for the progressive increase in its magnitude across the range of speeds. Moreover, the compatibility between the motions of the head-arm-trunk and of the shank in their general profile and peak magnitudes further suggested that a simplifying strategy may have been employed to reduce the overall number of degrees of freedom associated with the sit-to-stand movement.

Adult↗

PubMed1990

An assessment of the level of dental and mouthcare knowledge amongst nurses working with elderly patients.

A 60 item questionnaire was completed by a self-selected sample of nurses working with elderly patients. The questionnaire was divided into three sections; to collect personal data, to assess the nurses' attitude to mouthcare and their level of training in this subject, and to assess the level of dental knowledge. This paper identifies the disadvantages of using a self selected as opposed to a random sample. Analysis of the completed questionnaires revealed a fairly high level of basic training in dental and mouthcare matters. There was however, a paucity of specific dental knowledge e.g. there was some confusion over the aetiology and prevention of dental caries and also as to the difference between gingivitis and periodontitis. In addition, few nurses seemed to be aware of the effects systemic disease and drugs may have on the oral tissues. In spite of this most respondents achieved more than 50 per cent correct answers. A number of recommendations to improve nurses' dental knowledge is given at the end of the article.

Aged↗

PubMedDate not supplied

Determining HIV seroprevalence among women in women's health clinics.

Human immunodeficiency virus, type 1 (HIV), seroprevalence studies are needed to determine the level and trends of HIV infection among women attending family planning, abortion, and prenatal care clinics in the United States. A review of published and unpublished studies showed that HIV seroprevalence among women attending women's health clinics was 0 to 2.6 percent, although the studies were difficult to compare because of differences in methodology. The Centers for Disease Control, in association with State and local health departments, has developed a standardized protocol to determine HIV seroprevalence among women attending women's health clinics in selected metropolitan areas. Blinded HIV serosurveys (serologic test results not identified with a person) are being conducted annually in selected sentinel clinics in order to obtain estimates of HIV seroprevalence unbiased by self-selection, as well as to monitor trends in infection among clients attending these clinics. In areas with high HIV seroprevalence, nonblinded serosurveys (in which clients voluntarily agree to participate) will be used to assess behaviors that may place women at increased risk of exposure to HIV. Data from the surveys can be used in developing age-specific and culturally appropriate AIDS educational materials, assessing the amount and type of counseling activities required, and evaluating acquired immunodeficiency syndrome (AIDS) prevention activities. The information will provide epidemiologic data to complement the results of other surveys in characterizing the scope of HIV infection among women of childbearing age in the United States.

AIDS Serodiagnosis↗

PubMedDate not supplied

Using seroprevalence data in managing public health programs.

An objective of the Centers for Disease Control (CDC) family of HIV seroprevalence surveys, conducted by State and local health departments, is the collection of seroprevalence data that may be useful in managing public health programs. In prevention programs, seroprevalence data may be used in allocating resources, in determining the types and amount of education, counseling, and testing services offered, and in identifying access points for HIV-infected persons for medical followup and care. Over time, data will be useful in detecting and following trends in HIV infection and in evaluating the impact of program activities to prevent HIV infection. No single seroprevalence survey is representative of the entire population of a metropolitan area. Each type of survey has strengths and limitations that must be considered when interpreting seroprevalence data. However, results from the family of surveys are the best available data because they are relatively unaffected by self-selection bias, they are standardized, and the information is collected over time. Characterization of the population surveyed and adherence to standard CDC protocols improve the quality of the data. Consultants in health departments and at CDC form a network for providing technical support and disseminating data to health care providers and program managers.

AIDS Serodiagnosis↗

PubMed1990

Intake of essential and toxic trace elements in a random sample of Danish men as determined by the duplicate portion sampling technique.

Average daily intakes of essential and toxic trace elements from self-selected diets consumed by 100 men, selected as a random sample among the population of 30-34 year-old men in one urban and two rural areas of Denmark, were determined by the analysis of 48 h duplicate food portions. Median daily dietary intakes were 11.3 mg for zinc, 1.1 mg for copper, 11.3 mg for iron, 51 micrograms for selenium, 3.9 mg for manganese, 99 micrograms for molybdenum, 7 micrograms for lead and 11 micrograms for cadmium. Median dietary intake of mercury was below the detection limit. The observed nitrogen, sodium and potassium intakes were about 25% lower than the average total daily excretion of these constituents. It is therefore assumed that dietary intakes of nutrients during the duplicate portion sampling period were reduced by about 25% and that the observed intakes of trace elements can be regarded as minimum estimates of habitual intake. Taking this into consideration, it is concluded that the content of essential trace elements in Danish diets seems to be adequate and the amounts of the elements lead, mercury and cadmium are of little concern as regards health aspects.

Adult↗

PubMed1978

Update of naltrexone treatment.

To summarize, then, our work with naltrexone in a multi-modality treatment program indicates that it appeals to about 5-10 percent of narcotic addicts--those who conciously want to obtain drug-free status. It does significantly attentuate the effect of narcotics to the extent that they lose their reinforcing properties, and it has minimal side effects. Although we treated a self-selected population, it is noteworthy that about 10 percent of those who remained on naltrexone for more than a week were still opiate free 6 months after cessation of treatment. For some it appeared to be a turning point in their lives. It was the first time in years that they could live in their neighborhood and not be either intoxicated or occupied with the pursuit of narcotics. Our behavioral studies have identified a number of conditioned psychophysiological responses associated with the self-injection ritual. So far, although we have succeeded in extinguishing some of these responses, this has not resulted in an improved clinical outcome. We are currently working on more comprehensive behavioral treatments, but the clinical significance of these conditioned responses is uncertain at present.

Adult↗

PubMed1990

Sensitivity of the appetite control system in obese subjects to nutritional and serotoninergic challenges.

The sensitivity of the appetite system of a group of obese individuals was assessed in response to two challenges known to reduce hunger and enhance satiety in lean people. The challenges were the presentation of a caloric (high protein) load and the activation of serotonin systems. Eight obese female adults (BMI = 38) received 2 X 15 mg d-fenfluramine or placebo daily for 3 days, the study conforming to a 2 X 2 factor (drug X lunch type), double blind, repeated measures design. Three hours after dosing on day 3 they ate either a high carbohydrate (63 percent of total energy) or high protein (54 percent) lunchtime meal (the caloric load). These fixed meal challenges were equal in energy (475 kcal), weight and fat content. Ratings of hunger motivation and food preferences were tracked over the course of lunch and for a further 3 hours, at which point subjects returned for a self-selection test meal. Intakes from this second open meal revealed significant main effects of both caloric load and drug on energy intake, with the high protein d-fenfluramine combination being the most potent anorectic pairing. These findings were supported by the profiles of hunger motivation. This study has confirmed that the appetite system of these subjects was responsive to these biologically relevant challenges. The results suggest that the combination of an appetite modulating drug with specific dietary intervention may represent an effective strategy for the management of hunger arising from caloric restriction.

Adult↗

PubMed1990

Prevalence of anisometropia in volunteer laboratory and school screening populations.

For 10 years our laboratory has conducted, a longitudinal study of focusing and motor behavior of a volunteer population of 686 subjects aged 3 months to 9 years. Its purpose is to characterize normal refractive development in infants and children and to relate refractive anomalies to subsequent visual problems. Using age-related criteria for anisometropia adjusted to detect the most unusual 5% of the refractions on a test battery, we have found 19 nonstrabismic, anisometropic subjects (2.8% of total subject population). Of these, eight were either seen once or their anisometropia appeared at their last visit. Of the remaining 11 subjects, all had a reduction of their anisometropia to within normal limits on subsequent visits. Thus our current best estimate of persistent infant anisometropia is 0%, a startling result. By comparison, we found ten strabismic subjects (1.46%), two of whom had persistent anisometropia. Although we did not believe that anisometropic subjects could self-select and not participate in the study, it was possible that the volunteer laboratory population had characteristics atypical of the county at large. Thus we conducted a screening of 374 Head Start and first-grade pupils throughout the county, using the same methods. We found virtually no difference in the average refractive conditions between the laboratory and school populations and no significant difference in the prevalence of visual disorders. The very low prevalence of anisometropia in infants and young children in both populations has important implications for the etiology of anisometropic amblyopia.

Anisometropia↗

PubMed1990

Natural childbirth--the Johannesburg Hospital experience, 1983-1989.

The Johannesburg Hospital Active Birth Unit (ABU), the only one of its kind in southern Africa to date, has provided an alternative to conventional labour practices since 1983. In a retrospective study of the results achieved in this unit the intrapartum records of 492 patients admitted to the ABU between 1 March 1983 and 30 June 1989 were analysed. During the 6.3-year study period 364 patients (74%) successfully laboured and delivered within the unit. These figures included 50 underwater deliveries. One hundred and twenty-eight patients required intrapartum transfer to the conventional labour ward and of these 44 achieved spontaneous vaginal delivery. Thirty-four patients (7%) 'self-selecting' for natural childbirth ultimately required caesarean section delivery. Primiparous patients were more likely than their multiparous counterparts to require intrapartum transfer to the labour ward (38% v. 13%). Birth outcome results achieved in the Johannesburg Hospital ABU compare favourably with those for 6 other ABUs reported in the literature.

Female↗

PubMed1990

Occupational stress and well-being: do seafarers harbor more health problems than people on the shore?

The popular image of life at sea is one of stress: often difficult physical conditions, dislocation, isolation and less than ideal personal habits. In order to determine whether this stressful way of life is manifested when seamen's health status is assessed by standard measurements, we studied 144 sea captains and marine chief engineers as compared with a group of ordinarily employed men. The referent men were matched for age, ethnic origin, and level of education with the seamen. Outcome measures included a wide spectrum of physiological, psychological and behavioral indices. The comparisons revealed only mild differences between the two groups. Captains and chief engineers tend to harbor slightly higher levels of certain biochemical or physiological parameters (risk factors), such as serum cholesterol and uric acid, hemoglobin level and leukocyte count. Certain behavioral risk factors were more dominant among the seamen than among the control group (smoking level, alcohol consumption and lack of leisure-time physical activity). The study group did not exhibit a greater prevalence of overt disease or a higher degree of psychological symptoms. It is suggested that the group under study represents a self-selected group of persons well adjusted to their job and their special way of life.

Adult↗

PubMed1990

Physiologic and perceptual responses during treadmill running with ankle weights.

This study examined the effects of ankle weighting on physiologic and perceptual responses during treadmill running in seven healthy, female recreational runners with a mean maximal aerobic power of 48.4 +/- 4.0 ml/kg/min. Each subject completed four experimental one-mile runs at individually selected treadmill running speeds with 0, 1.6, 3.2 and 4.8 kg weights on their ankles. The subjects selected a speed at which they would run (train) if their objectives were to significantly improve cardiovascular function and induce weight loss. Metabolic and cardiovascular responses were continuously monitored, and ratings of perceived exertion were recorded near the end of the activity. During the unweighted run, the subjects selected a running speed of 6.87 +/- 0.63 mph which resulted in a net energy expenditure of 0.153 kcal/kg/min or 1.34 +/- 0.16 kcal/kg/mile. This corresponded to a training intensity of 76.3% +/- 5.1% of maximum oxygen consumption or 88.1% +/- 9.7% of maximum heart rate. Addition of weight to the ankles caused a significant decrease (p less than .05) in the running speed selected and, therefore, did not result in any significant changes (p greater than .05) in the rate of oxygen consumption, heart rate or ratings of perceived exertion when compared to the unweighted condition. These observations are in contrast to previous studies on ankle weighting which were conducted at fixed treadmill running speeds. However, the use of ankle weights did have a tendency to increase gross and net energy expenditure of running when values were expressed in kcal/mile because of slower self-selected running speeds under these conditions. This increase in energy expenditure could be of physiologic significance if running with ankle weights was performed on a regular basis at a fixed distance.

Adult↗

PubMed1990

dl-fenfluramine challenge to nutrient-specific textural preference conditioned by concurrent presentation of two diets.

Effects of the ingestion of protein and carbohydrate conditioned a preference for one size of chow particle over another, which was triggered by need for a specific nutrient. This learned elicitation of nutrient-specific dietary selection was not changed by injection of dl-fenfluramine HCl (2.5 mg/kg). This indicates that previously observed effects of fenfluramine on differential intakes of dextrin- and casein-rich diets do not depend on nutrient-specific self-selection.

Animals↗

PubMed1990

Ankle-foot orthoses: effect on energy expenditure of gait in spastic diplegic children.

This study examined the effect of conventional plastic bilateral ankle-foot orthoses (AFOs) on the energy expenditure of ambulation in spastic diplegic cerebral palsy patients. Eighteen subjects (aged 8.3 +/- 2.83 years) ambulated five minutes at freely chosen velocities with and without their AFOs. Heart rate (beats per minute) and distance (meters) ambulated were recorded for each minute. A physiologic cost index was calculated by determining the ratio of walking heart rate to velocity [(HRamb-HRrest) divided by meters per minute]. The mean physiologic cost indexes for the last three minutes of ambulation with and without orthoses were 1.34 +/- 0.69 beats per meter and 1.51 +/- 0.79 beats per meter, respectively (p less than 0.05). Ambulation heart rate, velocity and total distance traveled were not statistically different between the two trials. The results indicated that energy expenditure of ambulation at self-selected speeds in spastic diplegic children was reduced by the application of conventional AFOs. However, each child should be evaluated on a single-case basis because of individual differences.

Adolescent↗

PubMed1990

The effect of exercise on energy intake and body composition in overweight women.

Twelve moderately overweight women with mild obesity were studied to determine the effect of exercise on nutrient intake and body composition. The women, 16 to 42 percent above desired body weight (BW) and 30 to 41 percent body fat, rotated through three 18-day treatment periods: no exercise (NO-EX), moderate duration exercise (M-EX), and long duration exercise (L-EX). Daily exercise was prescribed to increase energy expenditure by 12.5 (M-EX) or 25 percent (L-EX) of energy intake required for BW maintenance during baseline. Diets were self-selected from a variety of conventional foods, and intake was monitored. Exercise did not affect quantity of energy intake or macronutrient composition of diets during the treatment periods. Energy and carbohydrate intakes tended to be higher in response to M-EX and L-EX compared to NO-EX during the last 5-day interval of the treatment periods, but these trends were not statistically significant. Exercise did affect BW and fat-free mass (FFM); mean FFM values were 49.3, 49.7 and 50.8 kg at the end of NO-EX, M-EX and L-EX, respectively (P = 0.017). Body fat mass (FM) was not consistently affected by exercise. It appears that exercise affects FFM but has no consistent effect on nutrient intake in mildly obese women who are choosing food intake from a variety of foods.

Adipose Tissue↗

PubMed1990

Patient selection and outcomes for out-of-hospital births in one family practice.

This paper reports a study of the pregnancies followed to delivery in one family medicine group practice that offered a choice of childbirth settings. Those choosing out-of-hospital birth (OHB) were a self-selected group of highly motivated couples interested in natural childbirth or desiring to minimize the cost of pregnancy care. Of 790 singleton pregnancies followed to term, 71 (9.0%) planned home births, 510 (64.6%) planned clinic births, and 209 (26.5%) planned hospital births. Of those planning clinic or home birth, 73% gave birth outside the hospital as planned (44 at home and 379 in the clinic), 81 (14%) changed plans prenatally and gave birth in a local hospital, 46 (8%) were transferred to the local hospital intrapartum, and 29 (5%) were referred to tertiary care. Primiparas who initially chose OHB were more likely than multiparas to give birth in a hospital (46% vs 16%). Controlling retrospectively for obstetric risk and parity, there were few differences in outcome between local hospital and out-of-hospital births. The observed rates of serious complications for OHB were low, but overall, 27% of those initially considered candidates for birth outside the hospital required a change to a higher level of care. For primiparas initially planning clinic or home birth, discriminant analysis revealed five variables that together might have improved the prediction of the eventual decision for hospital delivery in 46%. Clinical pelvimetry was the most powerful variable, in keeping with the finding that most intrapartum transfers were for arrests of labor. The results also suggest that financial factors and other features of the physician-patient relationship influenced clinical decision making.

Adult↗

PubMed1990

Control of body mass transfer as a function of speed of ascent in sit-to-stand.

The purpose of this study was to test the hypothesis that a progressive variation in the speed of ascent would result in differences in the horizontal and vertical motions of the body center of mass (CM) and in the governing impulse-momentum relationship. A motion analysis system and two force platforms were used to examine the STS task among 10 healthy adults at each of three self-selected speeds. As the speed of ascent became faster, a progressively earlier time to the maximum vertical linear momentum and an increase in its magnitude occurred. In contrast, a relatively constant time to the maximum linear momentum, which was also the time when the propulsive impulse became the braking impulse, was found in the horizontal direction, and the propulsive impulse showed a disproportionately (1:3) smaller increase from slow to fast speeds than its vertical counterpart. The relative invariance in the horizontal motion suggested that different neuromuscular control strategies may have been employed in the horizontal and vertical directions to accomplish the different tasks of balance control in one direction and changing the gravitational potential energy in the other direction.

Adult↗

PubMed1990

Oxygen uptake and heart rate responses to treadmill and water running.

The relationship between heart rate (HR) and oxygen uptake (VO2) was assessed during treadmill running and during running-like motions in water without ground support. Athletes self-selected easy, moderate and hard efforts during water running. While there was a linear relationship between HR and VO2 in both exercise conditions, there was considerable between-subject variability of the slope and intercept of the linear regressions. These data are taken to indicate that HR for a given VO2 during water compared to land running is influenced in large part by the skill of the athlete in the water running activity.

Adult↗