By monitoring two time points (one at mid-light and the other at mid-dark), the day-night variation of melatonin content in the retina of 19-day-old chicks was characterized. Melatonin was detected in the retina plus attached pigment epithelium by a specific radioimmunoassay, and its identity was verified by high performance liquid chromatography with electrochemical detection. Melatonin conten...

Article history: Received 15 January 2014 Received in revised form 15 July 2014 Accepted 2 September 2014 Available online xxxx Individuals with a propensity to wake up early in the morning (“early-morning” types) and those who like to stay up late at night (“night owls”) often exhibit distinctive psychological and physiological profiles. Previous research has shown that night owls score higher...

BACKGROUND & OBJECTIVES Decline in cognitive functions is a major challenge for professionals during sustained wakefulness. We used middle latency response (MLR), event related potentials P300-ERP and contingent negative variation (CNV) and Raven's Advanced Progressive Matrices (RAPM) - a standard neuropsychological test were used to evaluate cognitive impairment after total sleep deprivation (...

AIMS AND BACKGROUND The circadian pattern of stroke occurrence variation has been recognized with certain differences between authors and stroke types. The underlying reason may be related to exogenous factors (cyclic physical activity, including sleep-awake cycles and assuming the up-right posture) and endogenous factors, with their diurnal variation (blood pressure, hemostatic balance, autono...

The relationship between liquid equivalent snowfall rate and visibility is investigated using data collected at the National Center for Atmospheric Research Marshall Snowfall Test Site during two winter field seasons and using theoretical relationships. The observational data include simultaneous liquid equivalent snowfall rate, crystal types, and both automated and manual visibility measuremen...

human presence and accordingly establishing suitable condition for social interactions are important factors in shaping urban spaces. caring to different aspects of improving environmental qualities especially perception aspect and ease of perception from the environment with legibility improvement is an element that was emphasized from the base of urban design. the role of time, commence of da...