【推荐2】Spending your nights sleeping for just four seconds at a time might sound painful, but not for chinstrap penguins (帽带企鹅), which fall asleep thousands of times a day, new research finds.

Scientists studying the chinstrap penguins on King George Island in Antarctica found they nod off more than10,000 times a day, allowing them to keep an eye on their nests all the time, protecting eggs and chicks from predators (捕食性动物).

“Nesting penguins took over 600 ‘microsleeps’ an hour, each lasting only four seconds,” researchers wrote in the paper, published in the journal Science. The findings suggest “microsleeps can perform at least some of the functions of sleep”.

Sleep seems to be common among animals, but it makes them vulnerable because they lose the ability to respond quickly to the outside environment.

The researchers studied chinstrap penguins in the wild using electronicephalogram (EEG) monitoring. Microsleeps were shown by sleep-related brain activity and eye-closure. They noticed a slight increase in the depth of sleep at around noon, when risk of predation could be at its lowest.

Studies have shown some species routinely sleep very little, seemingly without negative costs to their performance while awake. African bush elephants sleep on average for two hours a day, and mostly while standing up, one study found. Sometimes they went 48 hours without sleeping.

Giant frigate birds can spend months on the wing during ocean migrations (迁徙). During this period they can sleep for less than an hour a day, while still flying and hunting. When they get back to the nest they sleep for nearly 13 hours a day.

“Sleep seems to be flexible among species,” a researcher said. “I believe that there are still many things unknown about animal sleep.”

【推荐3】You’ve most likely heard the news by now: A car-commuting, desk-bound, TV-watching lifestyle can be harmful to our health. All the time that we spend rooted in the chair is linked to increased risks of so many deadly diseases that experts have named this modern-day health epidemic the “sitting disease”.

Sitting for too long slows down the body’s metabolism (新陈代谢) and the way enzymes (酶) break down our fat reserves, raising both blood sugar levels and blood pressure. Small amounts of regular activity, even just standing and moving around, throughout the day is enough to bring the increased levels back down. And those small amounts of activity add up — 30 minutes of light activity in two or three-minute bursts can be just as effective as a half-hour block of exercise. But without that activity, blood sugar levels and blood pressure keep creeping up, steadily damaging the inside of the arteries and increasing the risk of diabetes, heart disease, stroke, and other serious diseases. In essence, fundamental changes in biology occur if you sit for too long.

But wait, you’re a runner. You needn’t worry about the harm of a sedentary lifestyle because you exercise regularly, right? Well, not so fast. Recent studies show that people spend an average of 64 hours a week sitting, whether or not they exercise 150 minutes a week as recommended by World Health Organization (WHO). Regular exercisers, furthermore, are found to be about 30 percent less active on days when they exercise. Overall, most people simply aren’t exercising or moving around enough to counteract all the harm that can result from sitting nine hours or more a day.

Scared straight out of your chair? Good. The remedy is as simple as standing up and taking activity breaks.

【推荐1】Every driver loves sailing through a series of green lights without having to stop and wait at a traffic light. Now, thanks to artificial intelligence, German researchers have found a way to reduce time spent at intersections. And they have gone further than that. This innovation is now being tested in the small German town of Lemgo.

For the research, scientists first studied algorithms taken from a busy intersection to learn about traffic patterns and where improvements were most needed. Actually, it is necessary to adjust waiting time at intersections as conventional methods are inflexible and cannot interpret all traffic flow patterns.

The new AI method uses radar sensors and high-resolution cameras to interpret traffic patterns in real time. They can determine the speed of traffic as well as waiting time and combine this with self-learning algorithms.

The intelligent lights are said to improve traffic flow by 10 to 15 percent, which results in money saved. (The EU estimates that traffic jams create economic damage that adds up to 100 billion Euros a year.) Aside from reducing commuting time, these traffic lights will reduce noise and CO₂ emissions from cars moving slowly at intersections.

Another exciting development in this research focuses on pedestrians crossing intersections. Using AI, researchers can confirm how many people are waiting at a pedestrian crossing and whether some of these people will need extra time to cross the street. Using a 3D points cloud, they can tell if someone has disabilities or is elderly without identifying the individual.

Testing will be done until this summer in the German towns of Lemgo and Bielefeld, with researchers optimistic that it will be adopted abroad. “We are the first team in the world to test deep reinforcement learning for traffic light control under real-world conditions. And our testing work has encouraged others to make similar efforts,” scientist Arthur Müller said.

【推荐2】Zebras are close relatives of horses and they are popular because of their unique black and white stripes (条纹). In fact, the most fascinating feature is their stripes and each zebra has a unique stripe pattern. It is this physical feature that makes them attractive and recognizable.

The body structure of zebras is similar to that of horses. Normally, the average height of an adult zebra ranges from four to five feet and the body length can be between seven and nine feet. An adult zebra weighs between 660 and 900 pounds. They have strong, rounded, muscular bodies with long legs and odd number of toes on each foot. Their faces are large and the ears are long and straight. The eyes are set high on their forehead, providing them with a wide range of vision(视野,视力). They have strong teeth, which help them to chew grass. The back-bone is straight and the tail is long.

The visual sense of zebras is very excellent, as they have both day and night vision. They have very acute senses of hearing and smell. They can hear distant sounds and are highly sensitive to smoke. Zebras’ diet mainly consists of grass. Occasionally their diet includes buds, roots, fruits, leaves and bark of trees. They need a lot of food to meet their daily nutritional requirement. Therefore, most of the daytime, they are busy chewing their food.

Zebras live in a wide range habitats like mountains, hills, woodlands and grasslands. Plains zebras prefer grasslands with trees and are usually seen near some water source. They are found in south and east Africa. Mountain zebras, as the name suggests, live up in the mountains in southwest Africa, where the atmosphere is cool. They are experts in climbing and like to take dust baths.