scholarly journals Homophily in delinquent behavior: The rise and fall of friend similarity across adolescence

2018 ◽  
Vol 43 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Ashley D. Richmond ◽  
Brett Laursen ◽  
Håkan Stattin
Keyword(s):  
Deviant Behavior ◽  
Community Sample ◽  
Delinquent Behavior ◽  
Group Differences ◽  
Cross Sectional ◽  
Age Related ◽  
Grade 5 ◽  
Intraclass Correlations ◽  
Self Reports ◽  
Age Related Changes

This study examined age-related changes in friend similarity on delinquency to determine whether deviant behavior homophily peaks during mid-adolescence. A community sample of 1,663 male and 1,826 female Swedish youth from Grade 5 ( M = 11.21 years) to Grade 10 ( M = 16.25 years) provided self-reports of delinquency. Friendships were identified from nominations. Intraclass correlations revealed age group differences in friend delinquency similarity, independent of normative age-related changes in deviant behavior. Cross-sectional results indicated that similarity was greatest in the seventh grade ( M = 13.21 years). Longitudinal results from a subsample of participants revealed an increase in friend similarity from ages 11 to 13 (Grades 5 to 7) and a decline in friend similarity from ages 14 to 16 (Grades 8 to 10). The findings demonstrate that similarity between friends in delinquent behavior peaks in mid-adolescence, independent of normative age-related changes in participation in deviant acts.

Ageing Changes in the Tensile Properties of Tendons: Influence of Collagen Fibril Volume Fraction

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
K. L. Goh ◽  
D. F. Holmes ◽  
H.-Y. Lu ◽  
S. Richardson ◽  
K. E. Kadler ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Collagen Fibril ◽  
Volume Fraction ◽  
Area Fraction ◽  
Sectional Area ◽  
Cross Sectional ◽  
P Values ◽  
Age Related ◽  
Fibril Diameter ◽  
Age Related Changes

Connective tissues are biological composites comprising of collagen fibrils embedded in (and reinforcing) the hydrated proteoglycan-rich (PG) gel within the extracellular matrices (ECMs). Age-related changes to the mechanical properties of tissues are often associated with changes to the structure of the ECM, namely, fibril diameter. However, quantitative attempts to correlate fibril diameter to mechanical properties have yielded inconclusive evidence. Here, we described a novel approach that was based on the rule of mixtures for fiber composites to evaluate the dependence of age-related changes in tendon tensile strength (σ) and stiffness (E) on the collagen fibril cross-sectional area fraction (ρ), which is related to the fibril volume fraction. Tail tendons from C57BL6 mice from age groups 1.6–35.3months old were stretched to failure to determine σ and E. Parallel measurements of ρ as a function of age were made using transmission electron microscopy. Mathematical models (rule of mixtures) of fibrils reinforcing a PG gel in tendons were used to investigate the influence of ρ on ageing changes in σ and E. The magnitudes of σ, E, and ρ increased rapidly from 1.6monthsto4.0months (P-values <0.05) before reaching a constant (age independent) from 4.0monthsto29.0months (P-values >0.05); this trend continued for E and ρ (P-values >0.05) from 29.0monthsto35.3months, but not for σ, which decreased gradually (P-values <0.05). Linear regression analysis revealed that age-related changes in σ and E correlated positively to ρ (P-values <0.05). Collagen fibril cross-sectional area fraction ρ is a significant predictor of ageing changes in σ and E in the tail tendons of C57BL6 mice.

Meta-analysis of the age-associated decline in maximal aerobic capacity in men: relation to training status

2000 ◽  
Vol 278 (3) ◽  
pp. H829-H834 ◽  
Author(s):  
Teresa M. Wilson ◽  
Hirofumi Tanaka
Keyword(s):  
Meta Analysis ◽  
Maximal Oxygen Consumption ◽  
Group Differences ◽  
Maximal Heart Rate ◽  
Maximal Aerobic Capacity ◽  
Cross Sectional ◽  
Physically Active ◽  
Age Related ◽  
Rate Of Decline ◽  
Exercise Status

Based on cross-sectional data, we recently reported that, in contrast to the prevailing view, the rate of decline in maximal oxygen consumption (V˙o 2 max) with age is greater in physically active compared with sedentary healthy women. We tested this hypothesis in men using a meta-analytic study ofV˙o 2 max values in the published literature. A total of 242 studies (538 subject groups and 13,828 subjects) met the inclusion criteria and were arbitrarily separated into sedentary (214 groups, 6,231 subjects), active (159 groups, 5,621 subjects), and endurance-trained (165 groups, 1,976 subjects) populations. Body fat percent increased with age in sedentary and active men ( P < 0.001), whereas no change was observed in endurance-trained men.V˙o 2 max was inversely and strongly related to age within each population ( r = −0.80 to −0.88, all P < 0.001) and was highest in endurance-trained and lowest in sedentary populations at any age. Absolute rates of decline inV˙o 2 max with age were not different ( P > 0.05) in sedentary (−4.0 ml ⋅ kg−1 ⋅ min−1 ⋅ decade−1), active (−4.0), and endurance-trained (−4.6) populations. Similarly, there were no group differences ( P > 0.05) in the relative (%) rates of decline inV˙o 2 max with advancing age (−8.7, −7.3, and −6.8%/decade, respectively). Maximal heart rate was inversely related to age within each population ( r = −0.88 to −0.93, all P < 0.001), but the rate of age-related reduction was not different among the populations. There was a significant decline in running mileage and speed with advancing age in the endurance-trained men. The present cross-sectional meta-analytic findings do not support the hypothesis that the rate of decline inV˙o 2 max with age is related to habitual aerobic exercise status in men.

scholarly journals Age‐related changes in chimpanzee ( Pan troglodytes ) cognition: Cross‐sectional and longitudinal analyses

2020 ◽  
Author(s):  
William D. Hopkins ◽  
Mary C. Mareno ◽  
Sarah J. Neal Webb ◽  
Steven J. Schapiro ◽  
Mary A. Raghanti ◽  
...  
Keyword(s):  
Pan Troglodytes ◽  
Longitudinal Analyses ◽  
Cross Sectional ◽  
Age Related ◽  
Age Related Changes

The Effect of Education on Age-Related Changes in Three Cognitive Domains: A Cross-Sectional Study in Primary Care

2012 ◽  
Vol 19 (4) ◽  
pp. 287-298 ◽  
Author(s):  
Isabel Pavão Martins ◽  
Carolina Maruta ◽  
Cláudia Silva ◽  
Pedro Rodrigues ◽  
Catarina Chester ◽  
...  
Keyword(s):  
Primary Care ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Cognitive Domains ◽  
Age Related ◽  
Age Related Changes

scholarly journals Age-related changes in the corpus callosum in early-onset bipolar disorder assessed using volumetric and cross-sectional measurements

2010 ◽  
Vol 4 (3-4) ◽  
pp. 220-231 ◽  
Author(s):  
Melissa Lopez-Larson ◽  
Janis L. Breeze ◽  
David N. Kennedy ◽  
Steven M. Hodge ◽  
Lena Tang ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Corpus Callosum ◽  
Early Onset ◽  
Cross Sectional ◽  
Age Related ◽  
Age Related Changes

Sex differences in the perceived intensity of breathlessness during exercise with advancing age

2008 ◽  
Vol 104 (6) ◽  
pp. 1583-1593 ◽  
Author(s):  
Dror Ofir ◽  
Pierantonio Laveneziana ◽  
Katherine A. Webb ◽  
Yuk-Miu Lam ◽  
Denis E. O'Donnell
Keyword(s):  
Sex Differences ◽  
Older Women ◽  
Cross Sectional Study ◽  
Inspiratory Muscle ◽  
Cross Sectional ◽  
Respiratory Impairment ◽  
Mechanical Constraints ◽  
Age Related ◽  
Underlying Mechanisms ◽  
Age Related Changes

The prevalence of activity-related breathlessness increases with age, particularly in women, but the specific underlying mechanisms have not been studied. This novel cross-sectional study was undertaken to examine the effects of age and sex, and their interaction, on the perceptual and ventilatory responses to incremental treadmill exercise in 73 healthy participants (age range 40–80 yr old) with normal pulmonary function. Age-related changes at a standardized oxygen uptake (V̇o2) during exercise included significant increases in breathlessness ratings (Borg scale), ventilation (V̇e), ventilatory equivalent for carbon dioxide, and the ratio of tidal volume (Vt) to dynamic inspiratory capacity (IC) (all P < 0.05). These changes were quantitatively similar in women ( n = 39) and in men ( n = 34). For the group as a whole, exertional breathlessness ratings increased as resting static inspiratory muscle strength diminished ( P = 0.05), as exercise ventilation increased relative to capacity ( P = 0.013) and as the Vt/IC ratio increased ( P = 0.003) during exercise. Older women (60–80 yr old, n = 23) reported greater ( P < 0.05) intensity of exertional breathlessness at a standardized V̇o2 and V̇e than age-matched men ( n = 16), despite similar age-related changes in ventilatory demand and dynamic ventilatory mechanics. These increases in breathlessness ratings in older women disappeared when sex differences in baseline maximal ventilatory capacity were accounted for. In conclusion, although increased exertional breathlessness with advancing age is multifactorial, contributory factors included higher ventilatory requirements during exercise, progressive inspiratory muscle weakness, and restrictive mechanical constraints on Vt expansion related to reduced IC. The sensory consequences of this age-related respiratory impairment were more pronounced in women, who, by nature, have relatively reduced maximal ventilatory reserve.

scholarly journals Quantifying age-related changes in brain and behavior: A longitudinal versus cross-sectional approach

eNeuro ◽  
2021 ◽  
pp. ENEURO.0273-21.2021
Author(s):  
Georgette Argiris ◽  
Yaakov Stern ◽  
Christian Habeck
Keyword(s):  
Cross Sectional ◽  
Age Related ◽  
Brain And Behavior ◽  
And Behavior ◽  
Age Related Changes

scholarly journals Exploring awareness of age-related changes among over 50s in the UK: findings from the PROTECT study

2021 ◽  
pp. 1-15
Author(s):  
Serena Sabatini ◽  
Obioha C. Ukoumunne ◽  
Clive Ballard ◽  
Rachel Collins ◽  
Anne Corbett ◽  
...  
Keyword(s):  
Thought Processes ◽  
Physical And Mental Health ◽  
Cross Sectional ◽  
Written Comments ◽  
Age Related ◽  
Perceived Age ◽  
The Uk ◽  
Protect Study ◽  
Age Related Changes ◽  
Theoretical Conceptualization

ABSTRACT Objectives: Older people describe positive and negative age-related changes, but we do not know much about what contributes to make them aware of these changes. We used content analysis to categorize participants’ written comments and explored the extent to which the identified categories mapped onto theoretical conceptualizations of influences on awareness of age-related change (AARC). Design: Cross-sectional observational study. Participants: The study sample comprised 609 UK individuals aged 50 years or over (mean (SD) age = 67.9 (7.6) years), enrolled in the PROTECT study. Measurements: Between January and March 2019, participants provided demographic information, completed a questionnaire assessing awareness of age-related change (AARC-10 SF), and responded to an open-ended question asking them to comment on their responses. Results: While some of the emerging categories were in line with the existing conceptual framework of AARC (e.g. experiencing negative changes and attitudes toward aging), others were novel (e.g. engagement in purposeful activities or in activities that distract from age-related thoughts). Analysis revealed some of the thought processes involved in selecting responses to the questionnaire items, demonstrating different ways in which people make sense of specific items. Conclusions: Results support the ability of the AARC questionnaire to capture perceived age-related changes in cognitive functioning, physical and mental health, and engagement in social activities and in healthy and adaptive behaviors. However, findings also suggest ways of enriching the theoretical conceptualization of how AARC develops and offer insights into interpretation of responses to measures of AARC.

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