Slashdot Mirror

Japanese researchers have found that even the slightest slither of light when trying to sleep could be linked to a heightened risk of depression, according to a new study published in The American Journal of Epidemiology. IFLScience reports: The reason behind this link is unclear, but the researchers believe it might be to do with the human circadian rhythm, the 24-hour cycle that tells us when to sleep and wake up, among other things, that is "programmed" by environmental factors. In the case of humans and many other creatures, light influences how much of the sleep-inducing hormone melatonin is pumped into our bodies, meaning we feel awake when the Sun rises and get sleepy when the Sun sets. This system works like a charm when there's only sunlight, moonlight, and a campfire to think about. However, the modern world is beaming with almost constant exposure to artificial light. Light at night (LAN) in a bedroom -- even a flash of a digital clock or streetlight creeping in from a crack in the curtains -- could screw with our natural sleep/wake cycle. The team behind the recent study assessed the sleep of almost 900 elderly people with no signs of depression. They found that people who slept in a room with 5 lux of light or more at night showed a "significantly higher depression risk" than those who slept in a completely dark room. For perspective, a household room with its lights on is around 80 lux and 10 lux is a single candle from 0.3 meters (1 foot) away.

An anonymous reader quotes a report from IFLScience: A new paper published in the journal Psychological Science has attempted to define and investigate the subject of free will. By asking participants to anticipate when they thought a specific color of circle would appear before them, something determined completely by chance, the researchers found that their predictions were more accurate when they had only a fraction of a second to guess than when they had more time. The participants subconsciously perceived the color change as it happened prior to making their mental choice, even though they always thought they made their prediction before the change occurred. They were getting the answers right because they already knew the answer. "Our minds may be rewriting history," Adam Bear, a Ph.D. student in the Department of Psychology at Yale University and lead author of the study, said in a statement. The implication here is that when it comes to very short time scales, even before we think we've made a conscious choice, our mind has already subconsciously decided for us, and free will is more of an illusion than we think.

An anonymous reader writes: As the climate continues to change in response to the increasing amount of carbon humans pump into the atmosphere, the oceans are being particularly hard hit from melting Arctic sea ice, acidification, and warming surface temperatures. Yet those are not the only difficulties that marine life has to deal with, as a new study reports that the oceans are also losing oxygen. As the majority of marine life relies on the oxygen dissolved in the oceans, it is worrying that noticeable differences have been observed in the gas concentrations in the world's waters. The reduction in oxygen will have profound effects on ocean biodiversity, though as the study published in Global Biogeochemical Cycles shows, not all regions will be affected in the same way or over the same period of time."Loss of oxygen in the ocean is one of the serious side effects of a warming atmosphere, and a major threat to marine life," said lead author Matthew Long of the National Center for Atmospheric Research. "Since oxygen concentrations in the ocean naturally vary depending on variations in winds and temperature at the surface, it's been challenging to attribute any deoxygenation to climate change. This new study tells us when we can expect the impact from climate change to overwhelm the natural variability."

Geoffrey.landis writes: Last week a news story suggested that a new model of sunspot activity predicted a dramatic drop in solar activity coming up, possibly resulting in coming a mini-ice age. Take that prediction with a bit of skepticism, though-- later news analysis suggests that the story may be more media hype than science. Valentina Zharkova, the scientist whose research is being quoted, made no mention of a "mini Ice age"-- her work was only on modelling the solar dynamo. And, in any case, the solar minimum predicted was estimated to last only three solar cycles-- far less than the 17th century Maunder Minimum.

Phil Plait, known for his "bad astronomy" column, does a more detailed analysis of the claims, pointing out that the effect, if it even exists at all, is weak-- and the much discussed "Little Ice Age" is currently believed to most likely have been triggered by volcanic action, not sunspots. And, in any case, any predicted cooling is small compared to already-present global warming. So, probably no need to stock up on firewood, dried food, and ammunition quite yet-- the mini ice age isn't likely to be coming quite yet.