The deadliest Ebola outbreak in history that has so far killed almost 1000 people in Guinea, Liberia, Sierra Leone and Nigeria in West Africa has caused fear around the world.

    The outbreak is unprecedented（空前的）both in infection numbers and in geographic scope. Officials from the World Health Organization (WHO) said earlier this month the outbreak “is moving faster than our efforts to control it”, reported CNN. So far, the battle against the virus doesn't appear to be slowing down.

    The Ebola virus is terrifying no matter where it strikes: It's a disease with no cure that causes headaches and fever, severe diarrhea(腹泻), vomiting and bleeding and has been known to kill up to 90 percent of its victims.

    It is understandable for people to be panicked, but those living outside Africa shouldn't be particularly concerned about contracting the virus, says a Washington Post article.

    This is because transmission of Ebola requires direct contact with an infected person's blood, vomit or other bodily fluids during the period that he or she is contagious(接触传染的). It is something that is extremely unlikely for anyone but healthcare workers. The virus is not spread by coughing or sneezing.

    Media outlets in the US and the UK are using terrifying headlines, wrongly claiming that people infected with the virus have traveled to their countries.

    James Ball at The Guardian says the Ebola outbreak in Africa is tragic, but it is important to keep a sense of proportion. Other infectious diseases, including common influenza, are far, far deadlier.

    Maddie Messe, 13, has always loved Temple Run, a mobile game that sends her racing through swamps (沼泽) and forests to outrun a pack of crazed monkeys. What she didn't love was being forced to play as a boy — unless she was willing to buy a female version. “I felt like l was being cheated or misrepresented,” Maddie explains．“Girls are just as capable (有能力的) of running away from monkeys as boys are.”

    So last winter, Maddie researched 50 of the most popular iPhone games. What she found was infuriating：90 percent offered free male characters, but only 15 percent let you play as a female for free.

    Armed with those statistics, Maddie drafted a spirited article and fired it off to several major newspapers. The Washington Post agreed to run the piece, which attracted millions of readers around the globe — including the makers of Temple Run! “We realized she had a point,” says Natalia Luckyanova, the game's co-creator. “It was the kick in the pants we needed to say, ' We should fix it．' So we did.”

    Now you can play Temple Run with a female character for free, but Maddie hopes her campaign inspires something deeper.“If you don't see characters that look like you on TV or in movies or games, speak up! Just do your research first,”says Maddie. “One well-supported argument is much more effective than a million angry complaints.”

    Feifei, an 11-year-old boy from Xuzhou, Jiangsu Province, suffered from a sudden acute eye disease which has almost led to blindness. The disease was caused by excessive(过度的)eye fatigue(疲劳)during the winter vacation, during which he played computer games for continuous 10 days and nights.

    Many youngsters in China nowadays are increasingly addicted to computer games and other electronic products. This is followed by a series of health problems, with the most typical case being myopia, or nearsightedness.

    According to the latest research report released by the World Health Organization (WHO), the myopia   rate among Chinese teenagers ranks first in the world—70 percent of high school and college students. The rate is nearly 40 percent in primary school students, while it is only 10 percent for their peers in the United States.

    There are at least 10 million people in China with severe myopia, and they are likely to get pathological(病理性的)myopia in middle age. Pathological myopia can't be treated with glasses or surgery, and it is one of the biggest factors that lead to blindness, Xu Xun, director of the ophthalmology(眼科学) department at Shanghai General Hospital, pointed out.

    Experts explain that two major factors lead to the high rate of myopia among Chinese people. One is high academic pressure, and the other one is excessive use of electronic devices over a long period of time. Genetics, on the other hand, are not the main reason, as only 20 percent of Chinese people had myopia in the 1960s.

    "Teenagers are now faced with severe academic pressure, which means they often study without natural light. This increases their risk of becoming nearsighted," Xu said.

    Experts suggest that youngsters maintain a proper balance between study and rest so as to protect their eyesight, and parents should play an active role in the process.

Let E-bikes Power New York's Transit Future

    Providence, R. I., just became the 13th city to develop an electric-assisted bike-share system, which runs or is developing bike-share networks in cities across the United States. Ironically, the Brooklyn-based company cannot operate in its hometown of New York City,due to the wrongheaded ban on electric bicycles.

    In many major cities in the U. S. and abroad, e-bikes are flourishing and helping to solve major urban challenges. Stockholm is adding 5, 000 e-bikes to its bike-share system. UPS is delivering packages in Hamburg using electrically-assisted cargo tricycles. And San Francisco's DoorDash food delivery service has found e-bikes to be the best mode to navigate heavy traffic and limited parking.

    In striking contrast, New York City insists e-bikes are banned under law. More than 900 e- bikes were seized and more than 1, 800 summonses（召回）were issued by the New York Police Department in 2017,following Mayor de Blasio's decision to limit e-bike usage, despite the fact that no data or records exist to show e-bike-related safety incidents.

    Who does the e-bike restriction hurt? The e-bikes seized in 2017 primarily belonged to food delivery workers, who are immigrants from Asia and Latin America. New Yorkers love their delivery: A new study from the New York City Department of Transportation found that more than half of city residents receive food deliveries at least a few times per month."

    In fact, the top three neighborhoods for e-bike summonses-the Upper East and West Sides and East Midtown-also consisted of more than 70% white residents. It's difficult to divorce the penalty of workers of color from the predominantly white, rich neighborhoods to whom the meals are delivered.

    It is true that the rush to maximize delivery numbers leads to higher speeds and potentially dangerous biking. To that end, the city should improve and enforce safe cycling and expand bicycling infrastructure to ensure safe passage for cyclists and pedestrians.

    Outside New York, cities and companies are finding that e-bikes are convenient, have low carbon footprints and require less space than cars on city streets. As New York City seeks to improve traffic, better air quality and encourage active modes of transportation, it is confusing that a mode that checks all of those boxes would be outlawed.

    The city must stop pedaling backwards on both workable transportation modes and the racially-charged policies surrounding them. It is time for New York City to embrace e-bikes as the very useful, worker-enabling, convenient and environmentally-forward mode that they are.

    Large gatherings such as weddings and conferences can be socially stressful. Pressure to learn people's names only adds to the stress. A new facial-recognition app could come to the rescue, .but privacy experts recommend going on with caution.

    The app, called SocialRecall, connects names with faces via smartphone cameras and facial recognition, potentially avoiding the need for formal introductions. "It breaks down these social barriers we all have when meting somebody," says Bany Sandrew, who Created the app and tested it at an event attended by about 10000 people.

    After receiving an invitation to download SocialRecall from an event organizer, the user is asked to take two selfies(自拍) and sign in via social median At the event, the app is active within a previously defined geographical area. When a user points his or her phone camera at an attendee's face, the app identifies the individual, displays the person's name, and links to his or her social media profile. To protect privacy, it recognizes only those who have agreed to participate. And the app's creators say it automatically deletes users' data after an event.

    Ann Cavoukian, a privacy expert who runs the Privacy by Design Center of Excellence praises the app's creators for these protective measures. She cautions, however, that when people choose to share their personal information with the app, they should know that "there may be unintended consequences down the road with that information being used in another context that might come back to bite you."

    The start-up has also developed a version of the app for individuals who suffer from prosopagnosia, or "face blindness", a condition that prevents people from recognizing individuals they have met. To use this app, a person first acquires an image of someone's face, from either the smartphone's camera or a photograph, and then tags it with a name. When the camera spots that same face in real life, the previously entered information is displayed. The collected data are stored only on a user's phone, according to the team behind the app.

Photographic self-portraits have existed for as long as cameras have been in human hands. But what about selfies in space? On Twitter last year, NASA astronaut Edwin Aldrin, who famously became the second man to walk on the moon in July 1969, laid claim to a spaceflight first: taking the first selfie in space during the Gemini XII mission in 1966.

"For me, it needs to be digital to be selfie," argues Jennifer Levasseur, a director at the Smithsonian National Air and Space Museum. According to Levasseur, the concept of a selfie is directly linked to internet culture. "The thing that makes a selfie is sharing it," she says.

Still, astronauts have been carrying cameras aboard space vehicles since the 1960s. In 1966, Aldrin used a Hasselblad camera designed specifically for space. Hasselblad also painted the first camera in space a matte(磨砂) black to reduce reflections in the orbiter window. But cameras used in space need to survive extreme conditions, like temperature swings from -149° to 248°F, so Hasselblad painted later model silver.

Astronauts visiting the moon then had to take out the film and leave their camera bodies behind when they returned to Earth, because early space missions were limited by a weight limit on the returned trip. Then a big change in space camera technology came after the space shuttle Columbia broke apart on its return to Earth in 2003, Levasseur notes. "Fear that they'd never be able to bring film back from space and lose all that hard work accelerated the push for digital," she says.

Today, astronauts also have access to internet and social platforms in space and can post true space selfies made using digital cameras. Similarly, space robots are participating in selfie culture, capturing remote pictures of themselves in space or on other planets and sending them back to Earth.