Recent quotes:

Study links exposure to nighttime artificial lights with elevated thyroid cancer risk -- ScienceDaily

Among 464,371 participants who were followed for an average of 12.8 years, 856 cases of thyroid cancer were diagnosed (384 in men and 472 in women). When compared with the lowest quintile of light at night, the highest quintile was associated with a 55 percent higher risk of developing thyroid cancer.

Blue-light glasses improve sleep and workday productivity, study finds -- ScienceDaily

Across two studies, researcher collected data from 63 company managers and 67 call center representatives at Brazil-based offices for a U.S. multinational financial firm and measured task performance from clients. Participants were randomly chosen to test glasses that filtered blue light or those that were placebo glasses. "Employees are often required to work early mornings, which may lead to a misalignment between their internal clock and the externally controlled work time," the researchers said, adding that their analyses showed a general pattern that blue-light filtration can have a cumulative effect on key performance variables, at least in the short term. "Blue-light exposure should also be of concern to organizations," Guarana said. "The ubiquity of the phenomenon suggests that control of blue-light exposure may be a viable first step for organizations to protect the circadian cycles of their employees from disruption."

Dead zones in circadian clocks -- ScienceDaily

One of the important properties of circadian clocks is the response to light signals, which enables organisms to become entrained to the 24-hour light-dark cycle on Earth. It has been shown that circadian clocks respond to light signals during the night, whereas they do not respond to such signals during the daytime. This holds true even when an organism is kept in complete darkness; a short light pulse does not change the time of the circadian clock when body time of the individual is at daytime. The time period in which the circadian clock is insensitive to light signals is referred to as the "dead zone." Previous studies have indicated that the presence of a dead zone improves the robustness of the clock. However, the mechanism underlying its generation is unclear.

Sensitivity of the circadian system to evening bright light in preschool‐age children

We found robust melatonin suppression (87.6 ± 10.0%) in response to the bright light stimulus. Melatonin levels remained attenuated for 50‐min after termination of the light stimulus (P < 0.008). Furthermore, melatonin levels did not return to 50% of those observed in the dim light condition 50‐min after the light exposure for 7/10 children.

Color-Changing LEDs Could Reset the Circadian Rhythm - The Atlantic

In much the same way as the ear allows us to both hear and stay balanced, the eye’s rods and cones supply us with vision while these novel intrinsic photosensitive retinal ganglion cells, or ipRGCs, perform a separate function: They sense the quality and quantity of light, with input from the rods and cones, and send that information to a master circadian clock in the brain. That clock then conducts a symphony of cellular timepieces throughout the body, ensuring they all “rise and fall with appropriate relationships to the others,” explains Berson.

Study links night exposure to blue light with breast and prostate cancer: Researchers used images taken by astronauts to evaluate outdoor lighting in Madrid and Barcelona -- ScienceDaily

Results obtained for both cities show that participants exposed to higher levels of blue light had a 1.5 and 2-fold higher risk of developing breast and prostate cancer, respectively, as compared to the less-exposed population.