نتایج جستجو برای: night light

تعداد نتایج: 426123  

Journal: :Investigative ophthalmology & visual science 1981
G Levinson B Burnside

The long, slender cones of the teleost retina elongate at night and contract during the day. In the Midas cichlid, Cichlasoma citrinellum, this cone excursion is elicited both by changes in light conditions and by strong endogenous circadian rhythms. In a normal day/night cycle. C. citrinellum cones change length by 69 micron. We have found that in this species an endogenous circadian rhythm in...

Journal: :Journal of physiological anthropology 2011
Shigekazu Higuchi Tomomi Fukuda Tomoaki Kozaki Masaya Takahashi Nobuhiko Miura

Bright light at night improves the alertness of night workers. Melatonin suppression induced by light at night is, however, reported to be a possible risk factor for breast cancer. Short-wavelength light has a strong impact on melatonin suppression. A red-visor cap can cut the short-wavelength light from the upper visual field selectively with no adverse effects on visibility. The purpose of th...

Journal: :The Journal of neuroscience : the official journal of the Society for Neuroscience 2003
Toshiyuki Hamada Joseph LeSauter Maria Lokshin Maria-Teresa Romero Lily Yan Judith M Venuti Rae Silver

It is well known that light resets the circadian clock only at specific times of day. The mechanisms mediating such gating of environmental input to the CNS are not well understood. We show that calbindinD28K (CalB)-containing cells of the suprachiasmatic nucleus (SCN), which are directly retinorecipient, gate photic entrainment of cellular circadian oscillators and thereby determine the timing...

Journal: :Industrial health 2002
Todd S Horowitz Takeshi Tanigawa

Night work is becoming increasingly common. Unfortunately, humans are physiologically unsuited to inverted schedules, leading to negative consequences for shift workers, employers, and society. The circadian and homeostatic processes which govern sleepiness and alertness are improperly aligned for night workers. We review a number of laboratory studies designed to treat circadian maladaptation ...

Journal: :Journal of biological rhythms 2013
Laura K Fonken Taryn G Aubrecht O Hecmarie Meléndez-Fernández Zachary M Weil Randy J Nelson

With the exception of high latitudes, life has evolved under bright days and dark nights. Most organisms have developed endogenously driven circadian rhythms that are synchronized to this daily light/dark cycle. In recent years, humans have shifted away from the naturally occurring solar light cycle in favor of artificial and sometimes irregular light schedules produced by electric lighting. Ex...

2002

N ight blindness—the inability to see after dusk or at night—is the most common ocular manifestation of moderate to severe vitamin A deficiency. Poor dark adaptation leading to night blindness occurs when there is decreased production of a vitamin A–dependent photosensitive pigment, rhodopsin, in the retinal receptors responsible for seeing under low levels of illumination (rods). Normally, whe...

Journal: :British medical journal 1986
N P Mann R Haddow L Stokes S Goodley N Rutter

The effect of alternating night and day on sleep, feeding, and weight gain in 41 healthy preterm infants was examined in a randomised controlled trial. Twenty infants from a night and day nursery, where the intensity of light and noise was reduced between 7 pm and 7 am, spent longer sleeping and less time feeding and gained more weight than 21 infants from a control nursery, where the intensity...

2005
KANAME NAKAJIMA YASUO NAKAOKA

Circadian changes in behaviour and electrical properties of the membrane were investigated in Paramecium bursaria. Both photoaccumulation and swimming velocity were at a higher level during the day than at night. During the day, swimming velocity decreased as light intensity was increased and the cells almost stopped at the intensity at which they showed the maximum degree of photoaccumulation....

Journal: :Plant & cell physiology 2003
Félicie Lopez Agnès Bousser Igor Sissoëff Marília Gaspar Bertrand Lachaise Jackson Hoarau Aline Mahé

In maize (Zea mays) roots, xylem water transfer supported by root pressure occurs during the day and is less important at night. Diurnal modifications of osmotic pressure gradient between medium and xylem could not explain the oscillation of water flux in young maize roots during the day-night cycle. We observed a high turgor pressure of root cortical cells associated with a high flux. In maize...

Journal: :Plant physiology 1970
H M Cathey H A Borthwick

Flowering of chrysanthemum plants under short photoperiods, as is well known, is prevented when the plants are illuminated near the middle of the long night. Such illumination inhibits flowering whether it is given continuously or intermittently, and whether it comes from incandescent or from fluorescent lamps. We discovered, however, that fluorescent light applied intermittently (cyclically) t...

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