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Is Sleep indisPensable? Science Advances


People have been aware of the importance of sleep for centuries and it is commonly believed that being sleep deprived is definitely not a good thing for our health. However, throughout the history, people have been questioning whether or not the statement above is really true and trying to minimize the amount of sleep. One of the most famous examples would be the sleep pattern of Leonardo da Vinci. Da Vinci followed a polyphasic sleep schedule called the Uberman sleep cycle, which consists of 20-minute naps every four hours. This sleep cycle enabled him to maximize his awake time during the day, while it compromised his ability to work on long term projects at the same time.
 
Scientists have long believed that sleep gives us an evolutionary edge since it helps conserve energy and give the brain time to organize memories. However, a new study recently published in Science Advances suggested that, at least for fruit flies, sleep may not be all that necessary.
 
In the new study, researchers noticed a very large distribution in sleep duration while observing fruit flies. Most slept somewhere between 300 minutes and 600 minutes per day, but about 6% of females slept for less than 72 minutes per day, and three particularly restless individuals slept for only 15, 14, or 4 minutes per day, respectively. Surprisingly, this lack of sleep seemed to have no ill effects on health. Even flies with typical sleep schedules weren’t bothered when housed inside a rotating tube that forced them to lose about 96% of their sleep time, the researchers reported.
 
The authors say their findings undercut the common wisdom that sleep plays an indispensable biological role. Instead, they say, we should adopt the view that sleep probably does serve some as-yet-unknown evolutionary purpose, but it isn’t strictly necessary.

Zebra stripes force insects to abort their landings, PLOS ONE


Why do zebras have stripes? Some people say that the stripes can confuse predators, while some others argue that they can actually help lower the body temperature of zebras. But none of these scientists were able to find solid evidence to support their argument. In 2014, a team discovered that the ranges of the horse fly and tsetse fly species and the three most distinctively striped zebra species (Equus burchelliE. zebra, and E. grevyi) overlap to a remarkable degree. They thus hypothesized that the stripes might have something to do with keeping off biting flies. Now, the team has find proofs to their argument and published their new findings on PLOS ONE.
 
In their experiments, the researchers used three zebras and nine monochromatically colored horses and dressed the with three different coats, one black, one white, and one striped (pictured) much like a zebra. Then they let the flies bite the animals. The zebra stripes did not deter flies from afar; both zebras and uncovered domestic horses experienced the same rate of circling flies. However, when analyzing the flies’ final approach to the animals, the team made some intriguing discoveries.
 
The scientists did not see a single tabanid probe a zebra’s skin during 5.3 hours of direct observation, whereas the flies successfully did so 239 times on the uncovered horses during 11 hours of observing them. More surprisingly, only five flies landed on the horses dressed in zebra coats during a 30-minute period, whereas more than 60 touched down on those in the solid black and solid white coats in the same time period and the flies attacked all the horses’ uncovered heads at the same rate.
 
Scientists concluded that the stripes do help prevent flies from biting the animals and they mainly affect the insects only at very close range. They also suggested that using zebra-striped coats may be a simple way to protect domestic horses from biting flies.

Having babies might not be compatible with full time STEM work

 
Though STEM works can generate a high salary, it is known to many researchers, as well as parents, that they can be unwelcoming to parents. Now, a new study backs that up with some startling numbers: After science, technology, engineering, and mathematics (STEM) professionals become parents, 43% of women and 23% of men switch fields, transition to part-time work, or leave the workforce entirely. For both genders, “the proportions were higher than we expected,” and the surprisingly high attrition rate for men also highlights that “parenthood in STEM is not just a mothers’ issue; it’s a worker issue,” according to Erin Cech, an assistant professor of sociology at the University of Michigan in Ann Arbor and lead author of the study, published in the Proceedings of the National Academy of Sciences.
 
However, sadly, having kids might not be the only reason for people to quit their STEM careers. This new study also suggested that it probably acts in concert with other contributors, says Donna Ginther, a professor of economics at the University of Kansas in Lawrence. Parenthood might not be the root cause. Rather, it could be the straw that broke the camel’s back. The real reasons might include societal expectations and stereotypes, hostile working environments, and outright discrimination. For example, someone who tolerates a negative work climate before they have children may decide, when they become a parent, that the tradeoff is no longer worth it.
 
“Is it the full story? Of course it’s not,” says Anna Kaatz from the University of Wisconsin, “But it’s more information. It leads us to say, ‘OK, let’s challenge academia and other sectors to get some hard numbers about reasons for attrition.’”
ISP Sci. Rev. 12 (2019)
Editor: Rossoneri Jing
Integrated Science Program
Northwestern University






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