Identifying patterns of weight-related health behaviors among US adolescents, and associated risk of obesity

Little is known about the current complex pattern of weight-related health behaviors among adolescents in the US. The goal of this report was to develop and examine a comprehensive latent class analysis (LCA) model examining the prevalence of combined associations of physical activities sedentary behaviors, and eating behaviors with obesity among female and male US adolescents (n= 12,031). Four classes and five classes were identified for female and male adolescents, respectively. Among which, three were similar and were characterized as ‘Inactive/ Low screen time/ Poor eating habit’, ‘Inactive/ Moderately high screen time/ Poor eating habit’, and ‘Active/ Low screen time/ Poor eating habit'. Additionally, ‘Inactive/ Low screen time/Good eating habit’ was unique to female adolescents, while ‘Moderately active/ High screen time/ Good eating habit' and ‘Moderately active/ Low screen time/ Good eating habit' were unique to males. Furthermore, the proportion of normal weight, overweight, and obese in each class was examined across females and males. The results showed that male adolescents had a higher proportion of people being obese than female adolescents in each class. The findings from this report provided insights on the current health needs of US adolescents and implied that gender-specific intervention strategies were required to reduce the risk of obesity among adolescents.Statistic

Media Screen Time for Young Children, a Culturally Competent Approach

Young children are being exposed to excessive screen time. There are many health and developmental risks of excessive or inappropriate media exposure, including sleep disturbances, developmental delays, and obesity. New American families are likely unaware of the consequences of too much screen time in young children.https://scholarworks.uvm.edu/fmclerk/1312/thumbnail.jp

The frequency of osteogenic activities and the pattern of intermittence between periods of physical activity and sedentary behaviour affects bone mineral content: the cross-sectional NHANES study

BACKGROUND: Sedentary behaviours, defined as non exercising seated activities, have been shown to have deleterious effects on health. It has been hypothesised that too much sitting time can have a detrimental effect on bone health in youth. The aim of this study is to test this hypothesis by exploring the association between objectively measured volume and patterns of time spent in sedentary behaviours, time spent in specific screen-based sedentary pursuits and bone mineral content (BMC) accrual in youth. METHODS: NHANES 2005–2006 cycle data includes BMC of the femoral and spinal region via dual-energy X-ray absorptiometry (DEXA), assessment of physical activity and sedentary behaviour patterns through accelerometry, self reported time spent in screen based pursuits (watching TV and using a computer), and frequency of vigorous playtime and strengthening activities. Multiple regression analysis, stratified by gender was performed on N = 671 males and N = 677 females aged from 8 to 22 years. RESULTS: Time spent in screen-based sedentary behaviours is negatively associated with femoral BMC (males and females) and spinal BMC (females only) after correction for time spent in moderate and vigorous activity. Regression coefficients indicate that an additional hour per day of screen-based sitting corresponds to a difference of −0.77 g femoral BMC in females [95% CI: -1.31 to −0.22] and of −0.45 g femoral BMC in males [95% CI: -0.83 to −0.06]. This association is attenuated when self-reported engagement in regular (average 5 times per week) strengthening exercise (for males) and vigorous playing (for both males and females) is taken into account. Total sitting time and non screen-based sitting do not appear to have a negative association with BMC, whereas screen based sedentary time does. Patterns of intermittence between periods of sitting and moderate to vigorous activity appears to be positively associated with bone health when activity is clustered in time and inter-spaced with long continuous bouts of sitting. CONCLUSIONS: Some specific sedentary pursuits (screen-based) are negatively associated with bone health in youth. This association is specific to gender and anatomical area. This relationship between screen-based time and bone health is independent of the total amount of physical activity measured objectively, but not independent of self-reported frequency of strengthening and vigorous play activities. The data clearly suggests that the frequency, rather than the volume, of osteogenic activities is important in counteracting the effect of sedentary behaviour on bone health. The pattern of intermittence between sedentary periods and activity also plays a role in bone accrual, with clustered short bouts of activity interspaced with long periods of sedentary behaviours appearing to be more beneficial than activities more evenly spread in time

Focusing and the Holographic Hypothesis

The ``screen mapping" introduced by Susskind to implement 't Hooft's holographic hypothesis is studied. For a single screen time, there are an infinite number of images of a black hole event horizon, almost all of which have smaller area on the screen than the horizon area. This is consistent with the focusing equation because of the existence of focal points. However, the {\it boundary} of the past (or future) of the screen obeys the area theorem, and so always gives an expanding map to the screen, as required by the holographic hypothesis. These considerations are illustrated with several axisymmetric static black hole spacetimes.Comment: 8 pages, plain latex, 5 figures included using psfi

"Do screen captures in manuals make a difference?": a comparison between textual and visual manuals

Examines the use of screen captures in manuals. Three types of manuals were compared: one textual and two visual. The two visual manuals differed in the type of screen capture that was used. One had screen captures that showed only the relevant part of the screen, whereas the other consisted of captures of the full screen. All manuals contained exactly the same textual information. We examined immediate use on time (use as a job aid) and on learning (use as a teacher). For job-aid purposes, there was no difference between the manuals. The visual manual with full-screen captures and the textual manual were both better for learning than the visual manual with partial screen captures. We found no effect on user motivation. The tentative conclusion of this study is that screen captures seem not to be vital for learning or immediate use. If one opts for including screen captures, then the conclusion is that full-screen captures are better than partial one

Two Screen Viewing and Social Relationships. Exploring the invisible backchannel of TV viewing

Use of social networks to create a real-time backchannel of\ud communication among viewers of television programs has been documented, and has been termed “two-screen viewing,” with one screen devoted to the program being watched, and a second screen (usually a laptop, tablet, or cell/mobile\ud phone) devoted to maintaining the backchannel. Prior research has examined twoscreen viewing through content analysis of social media posts. However, little has been done to explore the way in which two screen viewing qualitatively changes the viewing experience, or to understand how this behavior contributes to the construction or maintenance of social relationships. Couch (1992) noted that social interaction require a shared focus, a social objective, and congruent functional identities. The first screen program provides the shared focus. Using online interviews, this small pilot project seeks to discover whether social objectives and congruent functional identities are established through two-screen viewing. That is, the study explores how one might go about determining whether this communication actually contributes to social relationships or serves some other, asocial purpose. The present study is a small pilot project only. Preliminary\ud data suggest that there are two types of two-screen viewing defined by different degrees of visible and invisible online practice

Screen captures to support switching attention

The study set out to validate the supportive role of screen captures for switching attention. Forty-two participants learned how to work with Microsoft Excel with a paper manual. There were three types of manuals: a textual manual, a visual manual with full-screen captures, and a visual manual with a mixture of partial- and full-screen captures. The findings show that participants in all conditions looked up from the manual to the screen on about 97% of the cases in which such a switch was called for rank order analyses showed that users of the visual manuals switched attention significantly more often than did users of the textual manual. No differences were found between conditions on learning effects and training time

Gauss-Codazzi thermodynamics on the timelike screen

It is a known result by Jacobson that the flux of energy-matter through a local Rindler horizon is related with the expansion of the null generators in a way that mirrors the first law of thermodynamics. We extend such a result to a timelike screen of observers with finite acceleration. Since timelike curves have more freedom than null geodesics, the construction is more involved than Jacobson's and few geometrical constraints need to be imposed: the observers' acceleration has to be constant in time and everywhere orthogonal to the screen. Moreover, at any given time, the extrinsic curvature of the screen has to be flat. The latter requirement can be weakened by asking that the extrinsic curvature, if present at the beginning, evolves in time like on a cone and just rescales proportionally to the expansion.Comment: 8+1 pages, final versio