【推荐1】Scientists have created a new app designed to identify dangerous mosquitoes based on sounds the insects make. The app, called Abuzz, is aimed at helping fight major diseases spread by mosquitoes.

Haripriya Vaidehi Narayanan is one of the researchers who helped develop the app. Narayanan told VOA that anyone with a mobile phone could use the app to identify mosquitoes. “If they see a mosquito around, they just take out their phone, open up the app, point their phone towards the mosquito and hit the record button,”she said. “Then, when the mosquito flaps its wings and starts flying around, it makes that noise, that annoying buzzing noise. That noise is what gets recorded by the Abuzz app.” she added.

Many diseases that mosquitoes carry do not have cures or vaccines. So, targeting the flying insects is the best way to control them. “The most important step is to know where the mosquitoes are,” Narayanan said.

Traditional methods for hunting mosquitoes are costly and can take a very long time. The process also requires labor-intensive trapping as well as trained scientists to identify the insects.

Manu Prakash is a professor of bioengineering at Stanford University and a lead investigator on the project. He says that out of about 3,500 different mosquito species, only about 40 are dangerous to humans. Prakash says the goal of the project was to find out whether the mosquitoes around a person's house are just an annoyance, or whether they are possibly dangerous.

When mosquitoes move their wings up and down, they produce buzzing sounds. But each kind of mosquito makes a slightly different buzzing noise. The app records these sounds. Users of the app can get an answer by recording as little as one or two seconds of the buzzing sound. The app compares this recording to a collection of other recordings. It then predicts which species of mosquito it is most likely to be.

By making use of mosquito information worldwide, the app can help build maps of where dangerous mosquitoes are. This can help scientists and health officials identify areas where disease is likely to break out and where to target mosquito control.

【推荐1】The idea of unplugged running is gaining steam in the fitness community, as recent studies show that being addicted to tracking fitness metrics can lead to negative mindsets and outcomes.

Eoin Whelan, a senior lecturer in business information systems at the National University of Ireland Galway, explores the psychology behind engagement with social media and fitness tracking apps. “People are getting more enjoyment out of gathering the data and analyzing that and sharing it with other people”, Whelan told CNN, adding that there is a big element of social comparison for those who use fitness tracking apps. “People will compare themselves to people who are better than them, who are running faster or running longer. And ultimately we know that makes them feel bad.”

Whelan also noted that people who are very reliant on smartwatches. fitness trackers or fitness apps are more likely to skip their workout if the batteries on their tracking devices are dead. It’s like we can’t interpret our own body signals. We are becoming very dependent on the technology to actually do that for us. When you ask some of the athletes a simple question like “how did you sleep last night?” they can’t answer unless they look at the data.

Other researches show that too much screen time, including looking at our smartwatch or fitness apps, has negative impacts on mental health. The information people gather from smartwatches and workout tracking apps can contribute to “information overload” problems. Having a constant flow of information due to technology can lead to stress, anxiety, loss of sleep, depression, and more. The more we allow notifications and alerts to beckon (吸引) us, the more stress and anxiety chemicals are released, making us on edge and our mental and emotional systems are flooded with a message that says, “check me now”. Some experts advocate us to create screen-free zones as well as taking “tech breaks”, where we set a 15-or 30-timer during which we don’t check our phone. The time limit tells our brain that we can check the phone soon and reduces the anxiety of feeling we have to check in all the time.

Running watch-free is beneficial for more than just the casual jogger or weekend warrior. Some professionals also have had success with leaving their watches at home. Welsh runner Steve Jones famously set a world record at the 1984 Chicago Marathon without wearing a watch. He later told journalists he didn't even know he was on world record-pace until he crossed the finish line.

It’s not all negative, though. Other studies show there are many upsides to using fitness trackers. When using these technologies, some people tend to exercise for longer and at a higher intensity as well, which is all good for their physical well- being. So ditching the data might not be best for everyone.

【推荐2】The human body possesses an efficient defense system to battle with flu viruses. The immune system protects against the attack of harmful microbes (微生物) by producing chemicals called antibodies, which are programmed to destroy a specific type of microbe. They travel in the blood and search the body for invaders (入侵者). When they find an invasive microbe, antibodies attack and destroy any cell that contains the virus. However, flu viruses can be a terrible enemy. Even if your body successfully fights against the viruses, with their ability to evolve rapidly, your body may have no protection or immunity from the new ones.

Your body produces white blood cells to protect you against infectious diseases. Your body can detect invading microbes in your bloodstream because they carry antigens in their proteins. White blood cells in your immune system, such as T cells, can sense antigens in the viruses in your cells. Once your body finds an antigen, it takes immediate action in many different ways. For example, T cells produce more antibodies, call in cells that eat microbes, and destroy cells that are infected with a virus.

One of the best things about the immune system is that it will always remember a microbe it has fought before and know just how to fight it again in the future. Your body can learn to fight so well that your immune system can completely destroy a virus before you feel sick at all.

However, even the most cautious people can become infected. Fortunately, medical scientists have developed vaccines (疫苗), which are weakened or dead flu viruses that enter a person’s body before the person gets sick. These viruses cause the body to produce antibodies to attack and destroy the strong viruses that may invade during flu season.

【推荐3】Chewing uses a surprising amount of energy. An experiment that looked at the energy use associated with chewing gum (口香糖) found that it can increase bodily energy use by up to 15 per cent.

Adam van Casteren at the University of Manchester in the UK and his colleagues measured energy use in 21 people between 18 and 45 years old as they chewed gum for 15 minutes.

The gum was tasteless and calorie-free. “This way it doesn’t activate the digestive (消化的) system to the same extent as it otherwise would,” says van Casteren. “We wanted to measure just chewing or as close to chewing as we could get.

Each participant (参与者) was asked to chew two types of gum- one soft and the other tough-so they could compare the effects of the gum’s properties (性能) on the participants’ energy uses.

Energy use was measured using a plastic dome (半球形物) covering the participants’ heads. A monitor inside the dome measured oxygen intake and the amount of carbon dioxide released. “You can use this information to figure out how much energy is being used,” says van Casteren.

Before the experiment, the participants had all worn the plastic dome while they sat watching a film in order for the researchers to acquire their base level energy uses. The researchers found that chewing the soft gum raised energy use by about 10 per cent, while chewing the tougher gum increased this use by around 15 per cent. Van Casteren says it’s interesting that a small change in the properties of the gum had such a notable effect on energy use.

He says he expects the energy used to chew real food will be even larger as many foods such as steak and nuts require a lot of effort to break down. “I want to look at how much energy chewing nuts and seeds uses next,” he says.