Age-dependent association of exposure to television screen with children's urinary melatonin excretion?

OBJECTIVES: Changes in magnetic field are associated with a decrease in nocturnal urinary melatonin excretion. Television screens emit low and very low frequency electromagnetic waves (radiofrequencies and light) and exposure to them may be associated with a decrease in 24-hour melatonin in children's urine. Design and setting. An observational study in schools of Cavriglia, Italy, determined melatonin in 24-hour urines from 42 boys and 32 girls 6 to 13 years of age after one week of watching TV and after another week of abstaining from watching TV. RESULTS AND MAIN FINDINGS: In a gender- and age-dependent fashion, exposure to a television screen was associated with lower urinary melatonin concentrations, affecting particularly younger children at a pubertal stage when important changes in melatonin's time structure occur. CONCLUSION: Additional work should test further relations to growth, maturation and development, focusing on any adverse effect from exposure to a television screen also on obesity from a neuro-hormonal viewpoint, quite apart from any decreased activity and/or other lifestyle alterations associated with watching TV.     

Weather conditions and daily television use in the Netherlands, 1996–2005

This study examines the impact of daily atmospheric weather conditions on daily television use in the Netherlands for the period 1996–2005. The effects of the weather parameters are considered in the context of mood and mood management theory. It is proposed that inclement and uncomfortable weather conditions are associated with lower human mood, and that watching entertainment and avoiding informational programs may serve to repair such mood. We consequently hypothesize that people spend more time watching television if inclement and uncomfortable weather conditions (low temperatures, little sunshine, much precipitation, high wind velocity, less daylight) coincide with more airtime for entertainment programs, but that they view less if the same weather conditions coincide with more airtime devoted to information fare. We put this interaction thesis to a test using a time series analysis of daily television viewing data of the Dutch audience obtained from telemeters (T = 3,653), merged with meteorological weather station statistics and program broadcast figures, whilst controlling for a wide array of recurrent and one-time societal events. The results provide substantial support for the proposed interaction of program airtime and the weather parameters temperature and sunshine on aggregate television viewing time. Implications of the findings are discussed.     

“Blind focusing”: An objective method for avoiding errors of focus at the television texture analysis system (TAS)

Summary The amount of light energy a particle absorbs does not depend upon correct focus. The change in the path of light rays brought about by defocusing causes absorbing areas to be registered as areas of higher transmittance than when in focus. Already wellknown in photometry, this effect is put to use by the blind focus method at the television texture analysis system (TAS, Leitz). Some chromophores within the object to be measured are compared to a preset value of transmittance, for exampleT=0.40.Only the area representing the structures as dense or denser than the preset density are registered. If the structures are out of focus the size of the registered area is too low, since by defocusing, structures to be measured become pale and diffuse, the correct focus corresponds to the largest area to a preset value of transmittance.