Younger Categories Research Articles

Effects of Task Demands and Age on Vigilance and Subjective Workload

Sensory and cognitive vigilance were directly compared in two experiments. The question of whether sensory and cognitive vigilance task demands can be differentiated on the basis of perceived workload was also addressed. A third focus of the study was to investigate changes in sensory and cognitive vigilance across the adult life span. In Experiment 1 60 subjects from three age categories—young, middle, and elderly were studied. Experiment 2 consisted of 20 subjects from only the young and old age categories. Subjects performed a visual sensory and a cognitive vigilance task at low and high event rates. Each task used identical stimulus sets (pairs of digits) and differed only in the definition of a critical target. Task demands were a major determinant of vigilance performance. Cognitive vigilance was more resistant to decrement over time than sensory vigilance. On the other hand, the cognitive task was more adversely affected by high event rate than the sensory task. Older subjects had lower hit rates than young and middle-aged subjects on the cognitive task, particularly at the high event rate. Subjective workload results suggested that the increased mental demands required of the cognitive task at the high event rate were associated with performance differences between sensory and cognitive tasks. However, the results also revealed an apparent dissociation between performance and subjective workload measures. Implications of the results for display design and assessment of individual differences in monitoring capability are discussed.

Rehabilitation with removable dentures among the dentate population in Finland.

The information available on the rehabilitation with removable dentures among dentate subjects is contradictory. In the present study, the most common type of rehabilitation was a complete maxillary denture with or without a partial one. Nineteen per cent of men and 27% of women belonged to this category. Partial denture(s) without a complete one were worn by 11% of men and 15% of women. The odds ratio of having partial denture(s) was significantly higher among women, among people with a medium level of income, with a regular dental attendance pattern, and with a shorter distance to the nearest dental clinic. The presence of a complete denture significantly decreased the odds ratio of having a partial denture. The effect of age was non-significant in the two youngest age categories. The odds ratio of having a single complete denture was significantly higher among women, among people with a medium level of income and with a shorter distance to the nearest dental clinic. The presence of a partial denture and belonging to the oldest age bracket decreased the odds ratio significantly. Regularity of use of dental services had a non-significant effect.

Normal Cerebrospinal Fluid Values in Children: Another Look

Cerebrospinal fluid samples sterile for virus and bacteria from 371 patients who had no evidence of CNS pathology were examined. The patients were divided into five age categories. The white blood cell polymorphonuclear, and mononuclear cell counts were evaluated. The frequency distributions for these cell counts were markedly skewed, so values were calculated as percentiles for each age group. WBC values were highest for CSF obtained from patients in younger age categories, but 25% of patients from all age categories had two or three WBCs in their CSF. Patients from all but the 3- to 6-month category had three polymorphonuclear cells in their CSF 5% of the time. There was no significant difference in CSF WBC count between patients who had seizures and those who did not. Knowledge of normal values in different age groups is needed for the interpretation of CSF findings, but it should be used in conjunction with other clinical and laboratory findings.

Nederlands Voor Buitenlanders

The Delft Method is a so-called 'natural' method: the material corresponds as much as possible to the way in which people learn their first language. Characteristic properties of the material are: 1) integral presentation of the basic grammar at the beginning of the course, 2) presentation of a large and well-selected vocabulary, 3) complex lexical and grammatical exercises, 4) constant feedback, 5) absence of grammatical terminology. The Delft Method, as used at Delft University of Technology, is meant for students aged about 18, has a very high tempo and presupposes a lot of independent student activity. The course material is also used by students outside the university, coming from a much younger age category, having a considerably lower level of education and proceeding at a slower rate. A first comparison of the results shows that the method is natural enough to be successfully used by very heterogenous groups. Differences in the time used can be explained partly by differences in experience in studying: in this view people trained in studying learn a second language faster than could be expected ?by nature'.

Caffeine: use and abuse in sports.

The urinary caffeine content was compared between a control group and 775 cyclists checked for doping during the 1982 season. The data for sportsmen demonstrate that the (mis)use of caffeine is more pronounced in both professional and amateur classes than in the younger categories (debutant and junior). Caffeine was also monitored during a 60-h period in the urine of several coffee drinkers. Based on all results, a "maximum level of caffeine" of 15 micrograms X ml-1 in urine for sporting competitions is proposed.

The relative accuracy and reliability of histological aging methods

Histological aging methods of Kerley and of Ahlqvist and Damsten were applied to bone samples from thirteen individuals of known age at death. Relative accuracy and reliability were determined for six of Kerley's predicting formulas for the femur, fibula and tibia, and his profile method, Ahlqvist and Damsten's femoral predicting formulas, and age determined by averaging ages predicted by Kerley's six formulas. Averaging age estimates by Kerley's six formulas (mean regression) was found to produce the overall greatest accuracy and reliability. Dividing the sample into two age groups (13 - 51 and 60 - 102 years) altered the results only slightly. Kerley's femoral intact osteon formula produced the greatest accuracy for individuals in the younger age category, while his fibular osteon fragment formula was most accurate for older ages. Mean regression produced the greatest reliability for all age classes. Based upon both accuracy and reliability, averaging age predictions by Kerley's regression formulas appears to be the method of choice for broad application of histological aging.

FATAL AND NONFATAL CORONARY ATTACKS IN RELATION TO SMOKING IN SOME DUTCH COMMUNITIES

The association between acute coronary events (ACE) and cigarette or cigar smoking was evaluated in a case-referent study. The association was apparent for cigarette smokers of one and two packs daily. An association could be shown for cigar smoking also, with no appreciable difference between inhalers and non-inhalers. Cigarette smoking was related more strongly to rapidly fatal than to nonfatal ACE, especially in the younger age categories.

Differential leisure travel decision-making between spouses

Myers, Paul B. and Lewis W. Moncrief, “Differential Leisure Travel Decision-Making Between Spouses,· Annals of Tourism Research, Vol. V, No. 1 January/March 1978, pp. 157–165. Three hypotheses developed by Komarovsky on patterns of decision-making between spouses are examined using 1974 survey data. The leisure use choice analyzed is the selection of a pleasure travel destination, the route of the trip, and the commercial lodging utilized. None of Komarovsky's generalizations were supported by the authors' data. The three hypotheses were that wives in lower status families have comparatively greater influence in making choices; that joint decision-making is most frequent among couples in younger age categories; and that fewer joint decisions tend to be made at the bottom and top of the social hierarchy than among middle income groups. The data suggests that the destination decision is of greatest consequence to all parties concerned in that it is arrived at in more egalitarian fashion. Husbands dominate the route decision overwhelmingly while the lodging decision is shared in most cases, although husbands tend to have greater influence in the decision than wives if the decision is not shared.

Urinary Excretion of Cyclic Adenosine 3′,5′-Monophosphate in Children of Different Ages

The urinary excretion of cyclic AMP was investigated in 97 healthy children, 3 months to 16 years old. When the excretion was expressed as mumol/24 h an increase with age (r = 0.693, P less than 0.001) and an increase with body weight (r = 0.700, P less than 0.001) were found to be quite similar. In relation to surface area, the average excretion for children up to 91/2 years old was 4.45 +/- 1.71 mumol/m2 in constrast with 2.22 +/- 0.66 mumol/m2 in older children (P less than 0.001). The decline appears to be associated with approaching puberty. When cAMP excretion was related to urinary creatinine, an inverse correlation with age was found (r = -0.772, P less than 0.001). In the youngest category, 3 months to 4 years old, the ratio was 9.26 +/- 1.49 mumol/g creatinine vs 4.67 +/- 1.05 mumol/g creatinine in the age group 12 to 16 years old (P less than 0.001), which compares closely with the normal adult average of 4.34 +/- 1.25 mumol/g creatinine found in our previous study. Throughout there was no evidence of sex differentiation.

Coronary risk factors in a community. Findings in Tecumseh, Michigan.

In the Tecumseh study population examined from 1967 through 1969, 1457 men and 1607 women were separated into young (20-39 years), middle (40-54 years), and old (past 55 years) age categories. A subset of the study population, 183 men and 200 women who were repeatedly hyperglycemic according to a modified glucose tolerance test, were divided into the same age groups. Means and standard deviations of adiposity index, serum cholesterol, serum triglyceride, blood glucose, and systolic blood pressure were calculated for the total population and hyperglycemics. Correlation coefficients were determined for the relationship between adiposity index and each of the other variables and between paired variables exclusive adiposity index. Correlation coefficients for the latter relationships were recalculated after adjustment for the effect of adiposity. Means of variables were higher in middle and older age categories than in young age categories in both sexes, but the greatest incremental increases occurred between the young and middle-aged groups of men and between middle and old age groups among women. Men had significantly higher mean triglyceride and systolic blood pressure values than women in young and middle ages. Except for the cholesterol-triglyceride association, lipids, glucose, and systolic blood pressure were more highly correlated with adiposity than with each other. Correlations between variables were reduced by adjustment for adiposity. Hyperglycemics had higher mean adiposity indexes, serum lipids, and systolic blood pressures and generally higher correlations of variables than the entire study population. Much of the interrelationship of variables among hyperglycemics was associated with adiposity. Among men, higher mean triglyceride and systolic blood pressure levels, more frequent coexistence of risk factors, and a tendency to have large incremental increases in mean variables between young and middle age probably contribute to greater male susceptibility to ischemic heart disease. Levels of variables in the population and aggregation of coronary precursors in individuals are related to adiposity and hyperglycemia.

Legal Abortion: A Half-Decade of Experience

In the first 5 years of liberalized abortion laws approximately 850000 terminations have been performed in New York City about 1/2 of which were on city residents. There was a sharp rise in the number of legal abortions after the first year and then a subsequent drop. The increase in the number of resident women obtaining abortions has been attributed to an increased proportion of repeat abortions. In 1974 9 in 10 residents obtained abortions in the first trimester 8 in 10 of them by suction. The opposite is true among nonresidents. Difficulties in administrative procedures have apparently caused an increase in women obtaining late abortions via riskier procedures. The rise in abortions was greatest among teen-agers in the 17-year-old and younger category. Between 1971 and 1974 there was a 53% increase among residents in the ratio of legal abortions per 1000 live births and an increase by 28% in the rate per 1000 women aged 15-44. The ratios of 776 abortions per 1000 births in 1974 and 50.3 per 1000 of reproductive age were exhibited. Over the years more than 40% of resident women obtaining abortions have been nulliparous. Because of the increase in repeat abortions the proportion of never-pregnant has declined. This increase in repeat abortions is an indication of the need to produce a more reliable and safe contraceptive as well as to increase availability of family planning services.

Cohort Analysis of Church Attendance, 1939-69

An analysis of five different cohorts spanning a thirty-year period reveals little support for any particular model of church attendance as related to chronological aging. Although cohorts share trends in church attendance by sex and specific dates or time periods, each cohort seems to manifest its own distinct pattern as related to age itself. These findings suggest that even though church attendance varies by age, other factors such as specific cohort membership and general societal pressures may be more meaningful explanatory factors. A recurrent topic in the fields of both gerontology and sociology of religion is the relationship between church attendance and age. However, in spite of abundant research conducted on this topic, many questions remain largely unresolved, and a number of contradictory schools of thought still exist. Howard M. Bahr (1970) presents comprehensive descriptions of four models which have been used to classify research findings on the relationship between aging and church at-, tendance.1 He calls these four models traditional, stability, family-cycle, and disengagement. The traditional model views church attendance as reaching a low between the ages of 30 and 35, then increasing steadily until old age. The stability model sees church attendance as unrelated to age and as being fairly constant throughout one's lifetime. The family-cycle model suggests a relationship between age and church attendance depending on age-linked marriage and child rearing stages. According to this model, the peak in church attendance appears among young parents assumed to be concerned about their children's religious education. Finally, the disengagement model implies a gradual decline in church attendance from middle to old age. As the person ages, he gradually reduces his church-related activity along with other behavior patterns considered inappropriate for the aged in our society. The research of Cauter and Downham (1954), Fichter (1952; 1954), Glock et al. (1967), O'Reilly (1957), Smith (1966), as well as the writing of Argyle (1959) support the traditional model. That of Catholic Digest (1953; 1966), Lazerwitz (1961), Orbach (1961), and to some extent Streib (1965) upholds the stability model. Albrecht (1958) seems to be the chief exponent of the family life-cycle model, although Lazerwitz (1961) did find increased regularity of church attendance among Protestants with children five years old and older. The disengagement model finds support from the works of Barron (1958; 1961), Catholic Charities of St. Louis (1955), Hunter and Maurice (1953), McCann (1955), and Mayo (1951). A major source of confusion seems to arise from the two major methodological strategies used by the researchers noted above. We suspect that the existence of four empirically tested, yet contradictory models is due to the use of methodologies inappropriate for the problem. With the exception of a few restricted longitudinal studies (Streib, 1965), most of the research in this area can be classified as either cross-sectional or retrospective in nature. Crosssectional analyses assume that the activity pattern of those in younger age categories accurately portrays that of older people when they were younger. Such an approach ignores changes in behavior due to intergenerational differences as well as the possible existence of social change taking place during the lifetimes of respondents. In short, the cross-sectional approach presents a static view of behavior which often results in erroneous conclusions (Geriatric Focus, 1973). The retrospective approach attempts to approximate life-cycle patterns in church at* The authors thank the Roper Public Opinion Research Center, the University of Georgia Library System for making available the data used in this paper, and the University of Richmond which financed typing of the revised manuscript. 1 For a more complete summary and discussion of studies in this area, see Moberg (1965) and Orbach (1961).

Seasonal production of Andropogon gayanus

SummaryThe crude protein content and in vitro dry-matter digestibility (I.V.D.) of leaves and stems of Andropogon gayanus, grouped into four different age categories, were measured at weekly intervals during the secondhalf of the 1968 wet season. The crude protein content of all categories of leaf and stem rose to a maximumat ear emergence; significant reductions occurred thereafter, especiallyin the younger categories of leaf and stem. At any point in time the younger leaves and stems contained significantly more crude protein than the older leaves and stems.Although the mean crude protein content of each stem category was significantly lower than the corresponding leaf category, the young, elongating stems had a significantly higher crude protein content than the older, mature leaves at the time of ear emergence.The mean I.V.D. of all leaf and stem categories was highest at the start of the recording period. At ear emergence the I.V.D. of the young elongating stems was at least as high as the mature leaves. After ear emergence the I.V.D. of the stems fell more rapidly than the leaves.The results support the principle of cutting at ear emergence to achieve maximum yields of digestible nutrients.