Colour as a signal for entraining the mammalian circadian clock.

Twilight is characterised by changes in both quantity ("irradiance") and quality ("colour") of light. Animals use the variation in irradiance to adjust their internal circadian clocks, aligning their behaviour and physiology with the solar cycle. However, it is currently unknown whether changes in colour also contribute to this entrainment process. Using environmental measurements, we show here that mammalian blue-yellow colour discrimination provides a more reliable method of tracking twilight progression than simply measuring irradiance. We next use electrophysiological recordings to demonstrate that neurons in the mouse suprachiasmatic circadian clock display the cone-dependent spectral opponency required to make use of this information. Thus, our data show that some clock neurons are highly sensitive to changes in spectral composition occurring over twilight and that this input dictates their response to changes in irradiance. Finally, using mice housed under photoperiods with simulated dawn/dusk transitions, we confirm that spectral changes occurring during twilight are required for appropriate circadian alignment under natural conditions. Together, these data reveal a new sensory mechanism for telling time of day that would be available to any mammalian species capable of chromatic vision.

A modeling approach to determine how much UV radiation is available across the UK and Ireland for health risk and benefit studies.

A detailed map of the available UV across the UK from 2003 to 2012 is provided. A suite of data derived from climatologies and satellite observations are used to calculate spectral UV irradiance and related weighted doses (erythema, DNA damage, vitamin D). The result is a well-validated tool that has two advantages: (i) the output is simulated spectral UV irradiance that can be weighted with any action spectrum for use in any research studies that require ambient UV data, (ii) reliance on instruments with planned operational lives of at least several years that ensures data and method homogeneity for extension to future studies. The model-derived doses are satisfactory validated against spectral ground-based measurements at two sites. According to the calculated climatology, the southern part of the UK receives 1.5-2 times more UV than the north during spring, summer and autumn. During wintertime, the UV doses in the far north are an order of magnitude lower than southern values. Even for the same latitude, regional variations of cloudiness result in doses at coastal sites being up to 25% higher than inland areas.

Potential of wind turbines to elicit seizures under various meteorological conditions.

PURPOSE: To determine the potential risk of epileptic seizures from wind turbine shadow flicker under various meteorologic conditions. METHODS: We extend a previous model to include attenuation of sunlight by the atmosphere using the libradtran radiative transfer code. RESULTS: Under conditions in which observers look toward the horizon with their eyes open we find that there is risk when the observer is closer than 1.2 times the total turbine height when on land, and 2.8 times the total turbine height in marine environments, the risk limited by the size of the image of the sun's disc on the retina. When looking at the ground, where the shadow of the blade is cast, observers are at risk only when at a distance <36 times the blade width, the risk limited by image contrast. If the observer views the horizon and closes their eyes, however, the stimulus size and contrast ratio are epileptogenic for solar elevation angles down to approximately 5 degrees. DISCUSSION: Large turbines rotate at a rate below that at which the flicker is likely to present a risk, although there is a risk from smaller turbines that interrupt sunlight more than three times per second. For the scenarios considered, we find the risk is negligible at a distance more than about nine times the maximum height reached by the turbine blade, a distance similar to that in guidance from the United Kingdom planning authorities.

Gaps in the Postoperative Conversation: A Comprehensive Review of Current Practices and the Unmet Needs of Surgeons, Families, and Waiting Room Personnel.

Perioperative communication between surgeons and caregivers is an important aspect of patient care, with postoperative conversations (POCs) being critical. Literature suggests current communication practices may be suboptimal. Identifying barriers and opportunities could improve patient and caregiver satisfaction and increase surgeon efficiency. This mixed method study included 1) prospective study of all patients undergoing a surgery at an academic medical center between September 2014 and March 2016 and 2) nominal groups of physicians, caregivers, and waiting room personnel (WRP). Nominal groups ranked standard of care themes needing intervention. Multivariate logistic regression estimated the association of surgeon and procedure characteristics with POC practices considering both location and contact method. Data on 15,820 operations showed that surgical specialty (P ≤ 0.0001), inpatient status (P ≤ 0.0001), planned discharge destination (P = 0.0003), patient race (P = 0.02), and caregiver relationship (P ≤ 0.0001) were all significantly associated with receiving a private POC. Nominal group results provided opportunities for improvement: regular updates (caregivers), locating the caregivers postoperation (surgeons), clear communication between caregivers and surgeons (WRP). This study examines the perioperative communication. Surgeons, caregivers, and WRP identified effective communication as a top intervention priority. Managing caregiver expectations, addressing concerns of WRP, and creating an efficient environment for surgeons appear to be critical components to communication.