Time irreversibility, a fundamental property of nonequilibrium systems, should be of importance in assessing the status of physiological processes that operate over a wide range of scales. However, measurement of this property in living systems has been limited. We provide a computational method derived from basic physics assumptions to quantify time asymmetry over multiple scales and apply it ...

Human motor control systems orchestrate complex scale-invariant patterns of activity over a wide range of time scales (minutes to hours). The neural mechanisms underlying scale-invariance are unknown in humans. In rats, the master circadian pacemaker [suprachiasmatic nucleus (SCN)] is crucially involved in scale-invariant activity fluctuations over multiple time scales from minutes to 24 h. Agi...

It is clear that sex hormones impact ventilation. While the effects of the menstrual cycle, pregnancy, testosterone, and progesterone on resting ventilation have been well documented, effects of sex hormones on the hypoxic (HVR) and hypercapnic ventilatory responses (HCVR) are inconclusive. In addition, in no study have systemic sex steroid hormone levels been measured. Age and sex differences ...

Human age estimation has attracted increasing researches due to its wide applicability in such as security monitoring and advertisement recommendation. Although a variety of methods have been proposed, most of them focus only on the agespecific facial appearance. However, biological researches have shown that not only gender but also the aging difference between the male and the female inevitab...

Depigmentation of hair shafts is a hallmark human aging. However, it remains unclear how aging causes to grey. Here, we found that single session plucking via waxing grey in castrated mice. Moreover, this greying continued for several cycles. Given androgen secretion decreases with age both male and female humans, the present result suggests decrease may contribute age-related greying. I...

The purpose of this study was to examine relationships among memory aging knowledge and memory self-appraisal in college students and community-dwelling older adults. Participants completed the Knowledge of Memory Aging Questionnaire ([KMAQ] Cherry, Brigman, Hawley, & Reese, 2003) and the Memory Functioning Questionnaire ([MFQ] Gilewski, Zelinski, & Schaie, 1990). We hypothesized that poorer pe...

We investigated the kinetics of enthalpy recovery of several glass-forming polymers at temperatures significantly below the glass transition temperature (Tg) and for aging times up to one year. We find a double-step recovery at relatively low aging temperatures for the longest investigated aging times. The enthalpy recovered after the two-step decay approximately equals that expected by extrapo...

We investigate the velocity dependence of kinetic friction with a model that makes minimal assumptions on the actual mechanism of friction so that it can be applied at many scales, provided the system involves multicontact friction. Using a recently developed master equation approach, we investigate the influence of two concurrent processes. First, at a nonzero temperature, thermal fluctuations...

We use multispeckle dynamic light scattering to measure the dynamic structure factor, f(q,tau), of gels formed by aggregation of colloids. Although the gel is an elastic solid, f(q,tau) nearly completely decays on long time scales, with an unusual form, f(q, tau) approximately exp{-(tau/tau(f))(mu)}, with mu approximately 1.5 and with tau(f) proportional variant q(-1). A model for restructuring...

This three-sample study focused on changes in four key features of women’s personalities (identity, generativity, confident power, and concern about aging) over the course of middle age. Based on women’s retrospective and concurrent feelings about their lives in their 30s, 40s, and 50s, scales were developed and validated for the four themes. We found that identity certainty, generativity, conf...