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Age Changes (age + change)

Distribution by Scientific Domains

Life Sciences	42%

Selected Abstracts

Age Changes in Prosocial Responding and Moral Reasoning in Adolescence and Early Adulthood

JOURNAL OF RESEARCH ON ADOLESCENCE, Issue 3 2005
Nancy Eisenberg
Age changes' measures of prosocial responding and reasoning were examined. Participants' reports of helping, empathy-related responding, and prosocial moral reasoning were obtained in adolescence (from age 15,16 years) and into adulthood (to age 25,26 years). Perspective taking and approval/interpersonal oriented/stereotypic prosocial moral reasoning increased from adolescence into adulthood, whereas personal distress declined. Helping declined and then increased (a cubic trend). Prosocial moral judgment composite scores (and self-reflective empathic reasoning) generally increased from late adolescence into the early 20s (age 17,18 to 21,22) but either leveled off or declined slightly thereafter (i.e., showed linear and cubic trends); rudimentary needs-oriented reasoning showed the reverse pattern of change. The increase in self-reflective empathic moral reasoning was for females only. Thus, perspective taking and some aspects of prosocial moral reasoning,capacities with a strong sociocognitive basis,showed the clearest increases with age, whereas simple prosocial proclivities (i.e., helping, sympathy) did not increase with age. [source]

A Morphological Study of Age Changes in Adult Human Auricular Cartilage With Special Emphasis on Elastic Fibers

THE LARYNGOSCOPE, Issue 5 2001
Isamu Ito MD
Abstract Objective It is well known that the size of the human auricle increases after it has finished development. The reason why the size of the human auricle continues to enlarge until advanced age after reaching adulthood was investigated by observation of the ultrastructure of elastic fibers in human auricular cartilage. Methods A total of 1958 subjects (966 males and 992 females) were classified into 18 age groups from 0 to 5 years up to 85 years and above by 5-year intervals. Ear length, ear width, and length of ear attachment were measured with calipers. Human auricular cartilage was obtained from 26 subjects (16 males and 10 females) aged 14 to 79 years, stained by orcein, and examined by light and electron microscopy. Results Each item of measurement of human auricular size increased significantly with age in both males and females. On morphological examination by light and electron microscopy after orcein staining, elastic fibers in the cartilage were almost homogeneous in diameter and surrounded the cartilage lacuna in bundle-like fashion in young persons, whereas those in elderly persons were heterogeneous in thickness and had many fragments surrounding the territorial matrix. In elderly persons, collagen-like fibers and small vesicles with heterogeneous electron density were frequently observed near elastic bundles around the territorial matrix. Conclusion Structural changes of auricular cartilage associated with morphological age changes of elastic fibers may be one of the causes of expansion of the auricle after reaching adulthood. [source]

Age changes in bone microstructure: do they occur uniformly?

INTERNATIONAL JOURNAL OF OSTEOARCHAEOLOGY, Issue 6 2005
G. A. Macho
Abstract Age estimations based on conventional multifactorial methods were compared with trends observed in the internal morphology of bones obtained from high-resolution µCT. Specifically, average trabecular thickness and number of trabeculae/mm transect were determined in the non-load-bearing capitate (hand) and the load-bearing navicular (foot). The µCT findings reveal age-related trends but,surprisingly,these correspond only loosely with the ages assigned by conventional ageing methods, and are also not in accordance with what would be predicted from biomechanical considerations: trabeculae tend to be thinner in the (habitually) load-bearing navicular than in the (habitually) non-load-bearing capitate. While the statistically significant correlation between trabecular thickness and number of trabeculae would suggest a compensatory mechanism between these two aspects of microanatomy, they are not correlated with the assigned ages and, importantly, may differ between sexes. Only in females is there an unequivocal trend towards trabecular thickness increase with age. These findings, although unexpected, can be reconciled with recent histological evidence and assumed average activity levels in historical populations. Conversely, changes in trabecular number are less clear-cut and may be due to the lack of very old individuals in the sample. Nevertheless, the trends observed for trabecular thickness, as well as for trabecular number, seem to imply that the higher incidence of osteoporosis in women could be explained from a structural point of view alone. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Why Does head form change in children of immigrants?

AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2010
A reappraisal
Objectives: We test two specific hypotheses that explain the cranial changes Boas observed in Hebrews and Sicilians, namely that Hebrew change results from abandoning cradling of infants in America, while in Sicilians it results from impaired growth in America. Methods: Boas's (1928) data were used to test these hypotheses. The role of cradling in cranial shape was examined by comparing cranial indices of U.S.-born and foreign children between 1.5 and 5 years of age. Age changes in cranial index of Hebrew and Sicilian children ages five to eighteen were examined to demonstrate differing patterns of age changes, which could be explained by environmental differences. Statistical methods employed were t -tests, least squares, and loess regression. Results: The difference between American and foreign-born Hebrew children arose prior to five years of age, after which it remained constant. American and foreign-born Sicilians, on the other hand, had similar cranial indices at age five, and diverged during the growing years, primarily because American-born children did not exhibit the reduction in cranial index with age seen in the other groups. Conclusions: The results support the two hypotheses tested. Change in Hebrew cranial indices resulted from abandoning the practice of cradling infants in America. U.S.-born Sicilian children experienced an environment worse than the one in Europe, and consequently experienced impaired growth. We conclude that the changes Boas observed resulted from specific behavioral and economic conditions unique to each group, rather than a homogeneous American environment. Am. J. Hum. Biol. 22:702-707, 2010. © 2010Wiley-Liss, Inc. [source]

Size-independent age effects on reproductive effort in a small, short-lived fish

FRESHWATER BIOLOGY, Issue 5 2008
PABLO A. TEDESCO
Summary 1. Age-related changes in reproductive effort have been predicted by theoretical models and observed in a wide range of organisms. However, for indeterminate growers such as fish, an allometric relationship linking gonad weight to body size is commonly observed. There is often a positive linear relationship when these variables are log-transformed, which by implication reduces the influence of age on reproductive effort. 2. Contrasting with this usual pattern, we report a nonlinear relationship between gonad weight and fish size (after log-transformation) in mosquitofish (Gambusia holbrooki), clearly resulting from age changes. The declining rate of increase of gonad mass as a function of body size revealed a higher reproductive effort for younger individuals relative to size. 3. This size-independent age effect on reproductive effort was predicted based on previous studies of mosquitofish and is certainly related to their particular life-history strategy, combining an early maturation and short lifespan with the physiological costs of reproduction and over-wintering. Our findings probably apply to other small, short-lived species with similar life history. [source]