نکته مهم
    برنامه Twilight ممکن از باعث غیر قابل دسترس شدن دکمه نصب برنامه ها شود.  راه حل: 1) توقف Twilight از طریق نوار اطلاع رسان, 2) نصب برنامتان, 3) ادامه Twilight. باعرض پوزش برای این ناراحتی.
لطفا اصول اولیه در ریتم شبانه روزی و نقش ملاتونین را بخوانید:
http://en.m.wikipedia.org/wiki/Melatonin
http://en.m.wikipedia.org/wiki/Melanopsin
http://en.m.wikipedia.org/wiki/Circadian_rhythms
http://en.m.wikipedia.org/wiki/Circadian_rhythm_disorder
نمونه هایی از تحقیقات علمی مرتبط:
        Amplitude Reduction and Phase Shifts of Melatonin, Cortisol and Other Circadian Rhythms after a Gradual Advance of Sleep and Light Exposure in Humans
        Derk-Jan Dijk, Jeanne F. Duffy, Edward J. Silva, Theresa L. Shanahan, Diane B. Boivin, Charles A. Czeisler 2012
    
    Exposure to Room Light before Bedtime Suppresses Melatonin Onset and Shortens Melatonin Duration in Humans
    Joshua J. Gooley, Kyle Chamberlain, Kurt A. Smith, Sat Bir S. Khalsa, Shantha M. W. Rajaratnam, Eliza Van Reen, Jamie M. Zeitzer, Charles A. Czeisler, Steven W. 2011
    
    Effect of Light on Human Circadian Physiology
    Jeanne F. Duffy, Charles A. Czeisler 2009
    
    Efficacy of a single sequence of intermittent bright light pulses for delaying circadian phase in humans
    Claude Gronfier, Kenneth P. Wright, Richard E. Kronauer, Megan E. Jewett, Charles A. Czeisler 2009
    
    Intrinsic period and light intensity determine the phase relationship between melatonin and sleep in humans
    Kenneth P. Wright, Claude Gronfier, Jeanne F. Duffy, Charles A. Czeisler 2009
    
    The Impact of Sleep Timing and Bright Light Exposure on Attentional Impairment during Night Work
    Nayantara Santhi, Daniel Aeschbach, Todd S. Horowitz, Charles A. Czeisler 2008
    
    Short-Wavelength Light Sensitivity of Circadian, Pupillary, and Visual Awareness in Humans Lacking an Outer Retina
    Farhan H. Zaidi & Co. 2007