OBJECTIVES Emerging evidence suggests that inconsistent sleep may affect physical and psychological health. Thus, it is important to identify modifiable determinants of sleep variability. Screen time and physical activity are both thought to affect sleep, but studies of their relationship to sleep variability using objective measures are lacking. We examined cross-sectional associations between these variables in mid-teen adolescents using objectively measured sleep and activity. METHODS Wrist-worn accelerometers were used to measure one week of sleep and activity in 315 tenth grade students (mean age 15.8y) from six Reykjavík compulsory schools. Participants reported their daily hours of screen time. Regression analysis was used to explore associations of screen time and physical activity with variability in duration, quality, and timing of sleep, adjusting for DXA-measured body fat percentage, parental education, and physical activity or screen time. RESULTS Screen time, especially game playing, was associated with variability in duration, timing, and quality of sleep, most strongly with variation in bedtime. Physical activity was inversely associated with variability in duration, timing, and quality of sleep, most strongly with variation in the number of awakenings. Boys had less stable sleep patterns and higher screen time than girls, and sex-specific associations of screen time with sleep variability parameters were significant for boys only. CONCLUSIONS Less screen time and more physical activity were independently associated with less sleep variability among mid-teen adolescents. Our results indicate that encouraging youngsters toward an active lifestyle with limited screen use may be important to achieve more consistent sleep. OBJECTIVE The objective of the study was to characterize obstructive sleep apnea treatment patterns among older Americans with neurological conditions. SETTING AND PARTICIPANTS Claims data from a 5% fee-for-service sample of Medicare beneficiaries were analyzed to determine the proportion of older adults with OSA who received and were adherent to continuous positive airway pressure therapy and examine potential gaps in OSA care among neurological populations. Logistic regression was used to determine whether gender or race/ethnicity modified the associations between neurological morbidities and OSA treatment or adherence. RESULTS Data from n = 102,618 beneficiaries with OSA were identified. The prevalence of stroke, cognitive disorders, or Parkinson's disease in this sample was 7%, 3%, and 2% respectively. Overall, OSA-diagnosed individuals (73%) obtained treatment, and most treated were adherent to CPAP (72%). Lower proportions of OSA treatment and adherence were observed in neurological conditions, particularly stroke. In logistic regression models, gender and race/ethnicity each modified associations between neurological comorbidity and OSA treatment and adherence. Women as compared to men with a given neurological condition were uniformly less likely to receive CPAP or adhere to treatment (p less then 0.01 for each condition). Similarly, in comparison to whites with the same neurological condition, OSA treatment was significantly lower among all other races with stroke, and among blacks with cognitive disorders. CONCLUSIONS Older women and minorities with neurological conditions may be more vulnerable to gaps in OSA care. Targeted strategies to improve treatment disparities and neurological outcomes in older adults could be informed by these data. OBJECTIVES Methods for analyzing sleep as a dyadic behavior remain relatively unexplored. We aimed to (1) characterize how bedpartners influence each other's sleep, and (2) identify factors that predict sensitivity to wake transmission between bedpartners. DESIGN Cross-sectional study. SETTING Community members in Melbourne, Australia. see more PARTICIPANTS Fifty-five couples without sleep disorders, aged 18-72 years. MEASUREMENTS Participants completed the Morningness-Eveningness Questionnaire, reduced version. Habitual sleep/wake patterns were monitored for seven nights via actigraphy and sleep diary. Epoch-by-epoch sleep/wake concordances (shared sleep/wake minutes), number of transmissions received (number of awakenings immediately preceded by bedpartner wakefulness), percent transmissions received (percentage of total awakenings that were transmissions), transmissibility (percentage of all bedpartner awakenings transmitted), and percent minutes resistant to transmission (percentage of bedpartner's wake minutes that an individual slept), were calculated. Mixed-effects modeling assessed predictors of dyadic sleep. RESULTS We described rates of sleep concordance (M = 66.8% ± 6.8%), wake concordance (M = 6.8% ± 3.1%), number of transmissions received (M = 6.0 ± 2.7), percent transmissions received (M = 18.9% ± 7.5%), transmissibility (M = 20.0% ± 6.2%), and percent minutes resistant (M = 52.1% ± 13.6%). Average couple-level percent transmissions received were highest and percent minutes resistant lowest in couples who had similar bedtime (within 30 minutes), compared to couples with greater differences in bedtime. CONCLUSIONS Wake transmission is a useful metric of dyadic sleep, which varies according to relative bedtimes, and chronotypes of bedpartners. Higher wake transmissions for couples with similar bedtimes suggest dyadic preferences for shared bedtimes may be due to psychosocial benefits of shared sleep timing, rather than minimization of bedpartner-driven sleep disruption. Mammalian pregnancy creates unique challenges for immune systems highly evolved to detect and eliminate invading pathogens. Recognition of the challenges created by gestating a semi-allogeneic fetus evolved from the discipline of transplantation biology and were informed by studies on the unique natural parabiosis that occurs when female calves are gestated with twin male fetuses. These pregnancies typically result in an intersex female termed a freemartin, which revealed insights into development of the male and female reproductive tracts. However, they also uncovered important clues on immune tolerance with wide-ranging implications to reproductive biology, transplantation biology and autoimmune disease. Many studies focused on identifying mechanisms through which the fetus evades maternal immune detection and elimination. These included studies characterizing immune interactions between the fetus and mother at the nourishing interface of the placenta and uterine endometrium. This immunological forbearance only occurs under high concentrations of circulating progesterone.