【推荐3】A mysterious illness is turning some black bears friendly and unafraid of humans, among other strange symptoms.

Researchers believe the illness, which young bears around a year old appear to suffer from, is a kind of encephalitis (脑炎), according to a news report by the California Department of Fish and Wildlife late last month. Since 2014, a handful of bears in Nevada and Caledonia have shown signs of the condition, and four California bears were confirmed to have it last year. One of them walked into a school and entered a classroom where she sat down among the children, behaving very much like a friendly dog.

The encephalitis has other serious effects on the nervous system of the bears, including tremble, head tilts and seizures (癫痫). Affected bears also tend to be seriously underweight. One female bear, observed in February picking up an apple and eating it among humans in a yard, weighed only 21 pounds when she should have been around 80 pounds. She was also covered in ticks (扁虱), walked strangely and was ultimately euthanized (安乐死).

It’s still unclear exactly what's causing the brain illness. But in the course of studying the phenomenon, scientists have identified five previously unknown viruses in the affected bears.

Bears suffering from encephalitis typically have to be euthanized. Their symptoms make them unequipped to survive in the wild, and those placed in zoos or shelters can become a huge burden due to the lifelong medical care they need.

Two bears exhibiting neurological (神经系统的) issues in recent years, however, were able to find new homes. One, now named Elinor, was brought to the Orange County Zoo. The other bear, who has become famous after being caught on camera sniffing a snowboarder and is now named Benji, lives at the San Diego Humane Society’s Ramona Wildlife Center. Last month, Benji celebrated his third birthday there with a cake made out of fruit and potatoes. Details are as follows.

【推荐3】Flowing through winding streets of London were smells, so common during the Great Plague (瘟疫) of the 17th century that they almost meant the plague itself, historians said. For hundreds of years, people believed that disease was spread not through tiny drops or insect bites, but through taking in unpleasant smells. To purify the air around them, they would burn rosemary and hot tar.

Now, as the world faces another widespread outbreak, a team of historians and scientists from six European countries is seeking to identify and categorize the most common smells of daily life across Europe from the 16th century to the early 20th century and to study what changes in smells over time reveal about society.

The project will search through more than 250,000 images and thousands of texts, including medical textbooks, novels and magazines in seven languages. Researchers will use machine learning and AI to analyze references to smells. Once they are cataloged, researchers, working with chemists and perfumers, will re-create roughly 120 smells with the hope that museums will incorporate some of them into exhibits to make visits more immersive (沉浸式的) or memorable to museum-goers. The use of smells in exhibits could also make museums more accessible for blind people and those with limited sight, historians said.

“With smell, you can open up questions about national culture, global culture and differences between communities,” said Dr. Inger Leemans, a professor of cultural history at Vrije University Amsterdam. He said that introducing smells into museums or classrooms leads people to open up in discussions in ways they do not always do when discussing other issiues of national identity. “It is such an open topic and what we want to do is think about how we can bring history to the nose.”

【推荐1】Artificial cloud technology could soon be used in the fight against environmental damage. Researchers in Australia have used machines to spray salt water into the air, and noted that the reflective qualities of these artificial clouds helped protect the Great Barrier Reef from sun bleaching.

The so-called cloud brightening project works by thickening existing clouds and reducing sunlight exposure. No artificial chemicals make it into the clouds in the sky, and when water droplets steam they leave only small salt crystals that float up into the atmosphere. This provides a larger surface area for water vapor (水蒸气) to be liquids around them，forming thicker clouds.

Cloud manipulation (控制) is becoming more commonplace as climate change threatens to destroy our ecosystems. The past two years have seen unheard-of forest fires and droughts caused by the climate change emergency, meaning that widespread use of this technique may become more commonplace if carbon emissions are not controlled strictly.

Drones have also entered the cloud manipulation picture, being used in the United Arab Emeritus, a country desperately in need of more rainfall, to deliver electrical shocks to clouds in order to promote rainfall. Zapping (击打) clouds to produce a positive or negative charge within clouds can cause water droplets to form together. The greater the charge, the larger the droplets, vital for ensuring that as much rain as possible reaches the surface before steam gives off all the hard-won moisture (水分).

Even discounting climate change, global waterfall shortages are still an increasing concern, giving the planet’s booming population. More people means more mouths to feed, and the demand for water in agriculture for animals and crops further increases urgency for cloud manipulation technology. An increase in rain also leads to positive economic growth in many countries, as large harvests stabilize financial systems and living standards in all climates.

Increasingly, scientists are looking to our skies in providing solutions to protect our environment. Cloud manipulation technologies have promise; however, they can also be extremely expensive to run. For this field of science to become practical economically, more research needs to be done in making this process a practicable option in protecting our environment.

【推荐2】Procrastinators (拖延症患者)，take note: If you’ve tried building self-control and you’re still putting things off, maybe you need to try something different. One new approach: Check your mood.

Often, procrastinators attempt to avoid the anxiety or worry aroused by a tough task with activities aimed at repairing their mood, such as checking Facebook or taking a nap. But the pattern, which researchers call “giving in to feel good,” makes procrastinators feel worse later, when they face the consequences of missing a deadline or making a last-minute effort, says Timothy Pychyl, an associate professor of psychology at Carleton University.

Increasingly, psychologists and time-management consultants are focusing on a new strategy: helping procrastinators see how attempts at mood repair are destroying their efforts and learn to control their emotions in more productive ways.

The new approach is based on several studies in the past two years showing that negative emotions can damage attempts at self-control. It fills a gap among established time-management methods, which stress behavioral changes such as adopting a new organizing system or doing exercises to build willpower.

Researchers have come up with a playbook of strategies to help procrastinators turn mood repair to their advantage. Some are tried-and-true classics: Dr. Pychyl advises procrastinators to just get started, and make the doorstep for getting started quite low. “Procrastinators are more likely to put the technique to use when they understand how mood repair works,” says Dr. Pychyl, author of a 2013 book, “Solving the Procrastination Puzzle.” He adds,“A real motive power comes from doing what we intend to do—the things that are important to us.”

He also advises procrastinators to practice “time travel”—projecting themselves into the future to imagine the good feelings they will have after finishing a task, or the bad ones they will have if they don^’t. This cures procrastinators’ tendency to get so stuck in present anxieties and worries that they fail to think about the future.

Another mood-repair strategy, self-forgiveness, is aimed at dismissing the self-blame. University freshmen who forgave themselves for procrastinating on studying for the first exam in a course procrastinated less on the next exam, according to a recent study led by Michael Wohl, an associate professor of psychology at Carleton.

Thomas Flint learned about the technique by reading research on self-control, including studies by Dr. Sirois and Dr. Pychyl. He put it to use after his family moved recently to a new house. Instead of beating himself up for failing to unpack all the boxes gathered in his garage right away, Mr. Flint decided to forgive himself and start with a single step. I’d say, "OK, I’m going to take an hour, with a goal of getting the TV set up, and that's it, he says; then he watched a TV show as a reward. Allowing himself to do the task in stages, he says, is “a victory.”