【推荐2】Honeybees command a lot of attention in insect conservation circles, as they are important for pollinating our food supply. But the findings from researchers emphasize the importance of prioritizing other pollinators or insects like wild bees, moths and butterflies in conservation efforts, too.

For the study, ecologists Joshua Kohn and Dillon Travis from the University of California, painstakingly tracked the pollination of flowers from two plant species in San Diego — white sage and Phacelia distans. Often Travis sat for hours waiting for a single pollinator, honeybees or other insects, to land on a flower. Each time he put a mesh (网状的) bag on the flower to prevent any new visitor, then back to collect seeds from different visitors. Back in the greenhouse, the team grew the seeds, analyzing characteristics that reflected their quality, such as how many seeds grew and survived and how many leaves or flower seedlings (幼苗) grew from them.

They found flowers pollinated by honeybees make fewer and lower-quality seeds than flowers visited by other pollinators. The white sage and Phacelia distans plants produced roughly half the amount of seeds from flowers pollinated by honeybees compared with other pollinators. And Phacelia distans seeds from honeybee-pollinated plants grew into seedlings with fewer flowers.

The researchers also found that honeybees visited about twice as many flowers on one plant before moving to the next than the average of other pollinators, causing honeybees to transfer more pollen in flowers of the same plant, thus resulting in fewer and lower-quality and more inbred (近亲繁殖的) seeds. Other pollinators more often flew between different plants, probably transferring more diverse pollen.

Travis says, “Honeybees’ pollination habit can impact ecosystems and agriculture in the long term. One potential consequence could be that native plant populations decline as next generations become more inbred, reducing biodiversity.”

“It is time to actually shift our dependence for pollination from largely honeybees to other native species as well,” says Jaya Sravanthi Mokkapati, an entomologist at Penn State University.

【推荐1】After a long day at work, it feels so much better to just leave the dirty dishes in the sink — right? Don’t just call it laziness: After a long period of thinking hard, we tend to make decisions for relaxing in the short term but are worse overall, which appears to be a biological tool to fight against cognitive fatigue (疲乏), according to a new study published Thursday in the journal Current Biology.

“Influential theories suggested that fatigue, a feeling of being extremely tired, is a sort of illusion cooked up by the brain to make us stop whatever we are doing and turn to a more satisfying activity,” said study author Mathias Pessiglione, Inserm research director at the Brain and Spine Institute in Paris. “Our findings show that cognitive work results in a true functional change, so fatigue would indeed be a signal that makes us stop working, but for a different purpose: to protect the state of brain functioning.”

In the study, 40 people were given either an easy or a hard task that involved telling letters on a screen for more than six hours. Each participant was then offered choices of either an immediately satisfying smaller reward that required less cognitive (认知的) control or one that was higher value in the longer term but involved more cognitive control. Participants who had to think harder for the six-hour task were more likely to take the smaller reward. The researchers found that the harder the participants thought, the higher their levels of glutamate (谷氨酸盐).

After people spend long time thinking hard, the glutamate accumulation (积累) triggers a response in the brain, making it more difficult to use the prefrontal cortex, the area in the brain that allows us to control our thoughts, so that we make choices that are more impulsive (冲动的) than strategic.

If you are about to make an important decision, it’s important to make sure you aren’t too tired, said study author Antonius Wiehler, a cognitive neuroscientist and postdoctoral researcher at the Paris Brain Institute. But bad news is: It may also be difficult for people to accurately evaluate how fatigued they actually are.

【推荐2】Food poisoning is a harsh and often unexpected illness affecting your digestive tract (消化道), a common sickness acquired by 48 million Americans every year.

It is caused by “viruses, bacteria, and parasites (寄生虫)” present in food and drink. These harmful foreign pollutants can be caused by a failure to correctly prepare or cook food.     1    

The effects of food poisoning kick in within several hours after digesting the polluted substances, and usually won’t occur unnoticed. On rare occasions, food poisoning symptoms can take days to make themselves known.     2     Also the length of food poisoning can vary, lasting only a day or less and up to a week for others.

The stomach flu and food poisoning are constantly compared to each other.     3     The stomach flu has symptoms appearing between 12 hours to two days of the illness, while food poisoning is with immediate symptoms within hours.

The best cure for food poisoning is rest.     4     After a period of bad days and nights, your body will naturally recover. Water is of vital necessity as well. A consistently large intake of water can keep your body in good shape.     5    

【推荐3】Joseph Dituri hasn’t seen the sun for days. And he won’t see it again for months. Since March 1, the bio-medical engineer has been underwater, with the goal of spending 100 days there—for science.

The underwater living, if successful, will also break the current world record for time spent living underwater, which was set by two Tennessee biologists in 2014 when they stayed beneath the surface for 73 days.

Dituri, who uses the nickname Dr. Deep Sea, is living in Jules’ Undersea Lodge (小屋) in Key Largo, Florida—the same underwater spot where the previous record was set. The 100-square-foot hotel, which sits 30 feet below the surface, is his intended home until June 9, where he’ll be carrying out research and giving virtual lectures for his students at the University of South Florida.

As part of this research, Dituri is researching the effects of living in a high-pressure environment for an extended period. To keep water from entering the lodge, air must constantly be pumped into the space, which creates a pressure about 1.6 times that of Earth’s surface.

“The human body has never been underwater that long, so I will be monitored closely,” Dituri says in a press release. “This study will examine every way this journey affects my body.” Before taking the dive, Dituri had psychosocial, psychological and medical tests. He will continue to have testing during and after his 100 days at the lodge. He’s also taking doses of Vitamin D and keeping regular psychological appointments.

Beyond research, the project is also a chance to promote ocean protection and encourage young scientists. “The oceans are in a bit of trouble―the coral reefs are under attack, and the fishing industry is collapsing,” Thane Milhoan, habitat operations manager for Jules’ Undersea Lodge, says in a video. “We wanted to make use of the attention that the 100-day mission would demand to inspire the youth, more so than anybody, to get involved and start taking action.”

【推荐3】There are so many different methods claiming to predict marathon performance. But these are not always very accurate because predicting marathon performance is difficult. However, in our new study, we found it's possible to calculate a critical speed that we can use to predict a runner's marathon time with a good degree of accuracy.

Many things determine how fast you can run a marathon, your physical quality plays a huge role in your performance. For example, excellent marathon runners tend to be slim with long limbs. Fast marathon runners also tend to have a higher maximum rate of oxygen use (vo₂ max) and can operate at a high percentage of this maximum for a long time without developing tiredness. The right shoes can make running more economical in terms of how much energy you use. And of course, choosing a flat course with ideal weather conditions can help too.

Endurance (耐久力) running is essentially determined by the fastest speed you can sustain for a given distance. or how long you can run at a given speed. This suggests there is a critical speed which, in theory, we can sustain for quite a long time. It is quite possible that the critical speed is useful for predicting endurance performance.

By analyzing training data from 25,000 athletes, we found we could estimate their critical speeds and predict their marathon performance with 92% accuracy.

We also found that, on average, runners ran the marathon at speeds around 85% of their critical speeds. Faster athletes ran their marathons at close to 93% of their critical speeds, but slower runners did so at 79% of their critical speeds. This means that using training data to estimate your critical speed, certain fitness apps on your smart watch or phone may soon be able to predict your finish time at an even higher degree of accuracy, as well as providing real-time advice about how best to pace your race.