Adult Female Age Research Articles

THE POPULATION DYNAMICS OF NORTHERN SEA LIONS, 1975‐1985

Abstract: Populations of northern sea lions (Eumetopias jubatus) in the vicinity of Marmot Island, Alaska declined during 1975–1985 at about 5% per year (Merrick et al. 1987). The cause of this decline is not known. A life table for the northern sea lion was calculated assuming that life spans follow a Weibull distribution. Samples of northern sea lions taken in the vicinity of Marmot Island, Alaska during 1975–1978 and 1985–1986 indicate that the average age of females older than 3 yr increased about 1.55 yr (SD = 0.35 yr) while the population was declining at about 5% per year. Fecundity rates decreased by 10% over the same period, but the decrease was not statistically significant (Calkins and Goodwin 1988). Possible causes of the population decline and the change in age structure were examined by writing the Leslie matrix population equation in terms of changes in juvenile and adult survival rates and fecundity, and examining the short–term behavior of the trajectories of the average age of adult females, total number of females, and total number of pups with respect to those changes in the vital parameters. From the observed rate of declines of adults and the changes in average age of adult females and fecundity, estimates of the changes in adult and juvenile survival were calculated; estimates of the standard deviations of these changes were estimated via a bootstrap procedure. One purpose of this exercise is to aid in setting priorities for research for determining the cause of the decline. An explanation for the observed declines in numbers of adult sea lions consistent with the observed fecundity rates, a rate of decrease of 5% in the number of adults, and the corresponding increase in average age (of females age 3 yr and older) was a 10%–20% decrease in the survival of juveniles (age 0‐3 yr) coupled with an insignificant change in adult survival (0.03%, SD = 1%).

Widening Inequalities of Health in Britain: A Rejoinder to Rudolph Klein

Since the publication in 1980 of the Black Report, Inequalities in Health, critics have attempted to challenge its finding that for nearly all adult male and female age groups in Britain, inequalities in mortality between occupational class groups have widened during recent decades. This article seeks to refute one of the critics, using data published during the 1980s, and goes on to point out that if, as the Black Report also argued, material deprivation is the predominant scientific explanation for inequalities in mortality, then it is widening living standards between classes that we must examine to understand the trend.

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Effects of different electrodes on bioelectrical impedance values measured by the Selco bioelectrical impedance plethysmograph (SIF-881, Japan) were investigated using 8 adult females (age: 35.3 +/- 7.6 yr, Ht: 156.9 +/- 3.8 cm, Wt: 57.1 +/- 9.9 kg, and hydrodensitometrically determined body fat: 29.4 +/- 6.0%). The Lectec MP3000 electrode (Liberty Carton, USA) and the Bipolar electrode (Sanwa, Japan) produced significantly higher impedance values when compared to the Disposable electrode (Adovance, Japan) and the ECG electrode (Nihon Kohden, Japan). The coefficient of variation was significantly lower for the Disposable electrode (0.8%) and the ECG electrode (0.2%) than that for the Lectec MP3000 electrode (2.3%) and the Bipolar electrode (4.9%). In conclusion, the ECG electrode provides higher bioelectrical impedance values with the highest reproducibility in the assessment of human body composition by the bioelectrical impedance plethysmography.

Effect of Ascorbic Acid Supplementation on Haematological Response and Ascorbic Acid Status of Young Female Adults

Haematological response and ascorbic acid (AA) status were evaluated in 32 young adult females (age 20-34 years) 8 weeks after supplementation with two levels of AA (50 and 100 mg). Both levels of AA intake produced a similar response marked by significant elevation (p less than 0.01) in Hb concentration, Hct level, RBC count, serum and leucocyte ascorbate concentrations. Ten weeks after withdrawal of the supplements, values for all parameters evaluated decreased significantly (p less than 0.01) to presupplementation levels. Haemoglobin concentration and leucocyte ascorbate remained relatively higher (p less than 0.01) than initial values in subjects who received 100 mg AA. This study showed that AA supplementation improved erythropoietic activity and AA status of our female population. However, the higher dose of AA (100 mg) sustained Hb concentration and tissue ascorbate longer after withdrawal of supplementation.

Population Dynamics and Management of Baited Japanese Monkeys at Takasakiyama

A troop of Japanese monkeys at Takaskiyama has been artificially fed since 1953 and the population which divided into 3 and more troops grew from 250 to more than 1900 (Table 2). Artificially given food increased but, after 1975, decreased. Population parameters, especially growth rate, remaining rate to Takasakiyama, socionomic sex-ratio, adult female rate to the population size, birth rate to the adult female (natality) and primiparous age are compared with the food volume (Table 1) and with each other (Table 6). Nutrition given at the artificial feeding ground clearly influenced on the population parameters, especially on the growth rate, birth rate and primiparous age. Growth rate and socionomic sex ratio were influenced by the capture as agricultural pest, but remaining rate to Takasakiyama was not much influenced by the change of the nutrition. Changes of parameters were compared with those of the Ryozenyama population which was baited in a certain period and, then, left in the forest. The present nutrition intake by an animal at the artificial feeding ground as well as in the forest at Takasakiyama is a little more than that taken by wild animals. This study suggests that the artificial feeding should be controlled to the similar nutritional condition as that for wild animals.

Elderly listeners' estimates of vocal age in adult females.

The purpose of this study was to provide data on the ability of elderly listeners to estimate the age group of women (25-35, 45-55, 70-80) from phonated and whispered vowel productions. Further, comparisons were made between the performance of these elderly listeners and results for young listeners reported previously [S. E. Linville and H. Fisher, J. Acoust. Soc. Am. 78, 40-48 (1985)]. Tape recordings of whispered and normally phonated /ae/ vowels were played to 23 elderly women for relative age judgments. Results suggest that elderly women are not as accurate as young women in estimating age from sustained vowel productions, although the two listener groups tend to categorize individual speakers similarly. Further, it appears that listener age is a factor in acoustic cues used in making age judgments.

Parent-offspring food sharing: a statistical test of the early weaning hypothesis

Among non-human primates, Pan troglodytes and Leontopithecus rosalia are reported to show frequent parent-offspring food sharing. If sharing of solid foods could lead to early weaning, females in these species would reduce the energetic (nutrient transformation) and reproductive (delayed fertility) costs of lactation. Age at weaning in the two species is compared with the 95% confidence limits of the regressions that relate weaning age to adult female body weight, gestation length and age of sexual maturity in 52 primate species, since correlations with these variables must be taken into account to assess the food sharing-early weaning hypothesis statistically. P. troglodytes and L. rosalia fall within the confidence limits of the regressions in all cases but one, leading to rejection of the hypothesis. Food learning, in association with diet breadth, appears to be better supported as an alternative function for parent-offspring food sharing.

The influence of sex, sexual condition and age on the exploratory behaviour of wild wood mice ( Apodemus Sylvaticus L.)

From April 1978 to April 1980 the exploratory behaviour of more than 1000 wild wood mice was studied in a modified open field test situation. The influence of sex, sexual condition and age on the exploratory activity was investigated. Sufficient data being available, the exploratory activity of both sexually active and sexually inactive adult males and adult females, of both sexually active and sexually inactive subadult males and subadult females and of both sexually inactive juvenile males and females was compared by means of a one way analysis of variance for each two-month period. In other analyses the influence of age of adult males and adult females on the exploratory behaviour was further examined. No differences could be found in the exploratory activity displayed by males or females and by sexually active or sexually inactive animals. Also a clear influence of age was absent. The interindividual variation was very large.

Uric Acid Quantities in the Fat Body of Normal and Aposymbiotic German Cockroaches, Blattella germanica

Uric acid was measured in fat body of several age groups of the German cockroach, Blattella germanica (L.). Fat body was dissected from insects and dried to constant weight; uric acid was measured on a percentage dry weight basis using an enzyme-specific assay with uricase. Aposymbiotic last stage nymphs contained about twice as much uric acid as normal nymphs (means of 48 and 23%, respectively). Uric acid increased with high significance in normal nymphs during the last stage. There was a marginally significant increase (mean of 54%) with age in aposymbiotic adult females, while normal adult females showed a highly significant increase and much greater variation (between 18 and 87%) than the other groups tested. Both adult normal and adult aposymbiotic males showed increases in uric acid with age in asymptotic fashion, approaching mean maximum values of about 72 and 81%, respectively.

Comparison of the Relation between Integrated EMG and Force in Some Limb Muscles

The relation between integrated EMG and tension during voluntary isometric contraction was compared in each of the following: M. flexor pollicis brevis, M. biceps brachii, M. rectus femoris, M. biceps femoris and M. tibialis anterior. Also relation between EMG recorded from each muscle and skinfold thickness above that muscle was investigated.Experiments were made on total of 15 young adult females (age 21-22).Integrated surface EMG was recorded during the mid portion of 8 sec. period of sustaining contraction. The exerted force measured at distal phalange of pollex, wrist and ankle was 1, 3, 5, 7 and 10kg. Maximal and 1/2 maximal contraction was also made. Skinfold thickness on the muscle were measured with skinfold caliper. Results are summarized as follows:1) Integrated EMG increased approximately linearly with exerted force in every muscle.The slope of regression lines for various muscles differed markedly. Regression coefficient were decreasing in the followig order:M. flexor pollicis brevis, M. biceps brachii, M. tibialis anterior, M. triceps brachii, M. biceps femoris, M. rectus femoris.2) Analysis was made relationship between the maximum value of integrated EMG (that is EMG obtained during maximal contraction) and skinfold thikness. As regards paticular muscle, individual variation of the skinfold thickness above that muscle showed no systematic variation with integrated EMG. When various muscles are viewed as whole, however, significant negative correlation between integrated EMG and skinfold thickness was found.After logarithmic transformation for integrated EMG (Y, arbitrary unit) and skinfold thickness (X, cm), linear regression line was fitted. The regression coefficient was -0.661, (r=-0.568) showing that original relationship can be expressed by the formula Y=aX-0.661 where a is constant.3) By means of analysis of covariance, the maximum integrated EMG for each subject and for each muscle was adjusted to the skinfold thickness. There still remained significant difference among various muscles concerning the maximal EMG. Examined muscles could be arranged in the following decreasing order with respect to maximal EMG: M. flexor pollicis brevis, M. biceps brachii, M. tibialis anterior, M. triceps brachii, M. biceps femoris, M. rectus femoris.

Blood pressure of Amerindians from Surinam.

AbstractBlood pressures of members of the Trio and Wajana tribes from Surinam have been analysed in relation to age, stature and weight. The sample is representative of a group living in a hunting and gathering economy but beginning to come into jarring contact with an alien culture. Diastolic pressure does not alter significantly with age in adults of either sex. There is a small but significant increase in systolic pressure with age in adult females but in males there is an apparent decrease. This decrease is probably an artifact of the cross‐sectional survey approach. The high pressure in some young adults is discussed with reference to psychosocial stress. Mean blood pressures are given for children from five years of age onwards.

Study of age misstatement among young children in Ghana

In the 1960 Population Census of Ghana, the first attempt to enumerate the population by single years of age was made. The use of these data to estimate fertility levels was rendered somewhat difficult by the pattern assumed by the age statement of children. This pattern was similar to others found widely in developing countries. There appeared to be unexpectedly few children under two years of age and more children aged three years than any other single age. In order to investigate such age reporting, and in the hope of being able to provide some kind of correction to the census data, an attempt was made to trace one thousand children 0-99 months of age in ten different centers, with knoum dates of registered birth. If found, they were approached, as if by census enumerators, to obtain statements of age from the families. The investigation had to be confined to the compulsory registration areas where an eighth of the population of the country lives.It was found that age misstatement occurs partly because of digital preference but even more commonly because of a tendency to approximate age to the nearest birthday. Thus, when age misstatement occurs through the latter cause, it always takes the form of age advancement. Errors in age statement of more than one year fell evenly and randomly above and below the correct age. The age data in years were not appreciably affected by seeking further information on age in years and months. However, it was shown that the standard deviation of stated from real age was approximately proportional to real age and was equal to about one-eighth of it.The findings were then applied to the 1960 enumeration, where some problems such as the small number of one-year-olds, were solved. More work is needed to explain satisfactorily the peaking at three years of age. It was shown that age advancement may have reduced the size of the 0-4 age group by about 5 percent relative to adult female age groups, and this would result in an understatement of fertility as measured by the child/woman age ratio of the same amount.The research described in this paper was program of that post. With the exception of a carried out when the writer held the Population part of the analysis which has been carried out at Council demography post attached to the University of Ghana and formed part of the research program of that post. With the exception of a carried out when the writer held the Population part of the analysis which has been carried out at the Australian National University, the project was financed entirely by the Population Council.