1 . Facebook is a habit forming activity， but users who spend a lot of time on the site say they feel less happy with their lives.

Researchers from University of Gothenburg say that many users log in as soon as they turn their PCs on and that the behavior can develop into an“addiction”. People in low income groups and the poorly educated are particularly at risk. Up to 85% of users say that they use Facebook daily and half say they start up Facebook as soon as they open their web users. Half fear that they are not“on top of things”if they are not logged into the site, and 25% say they feel”ill at ease”if they can't log in regularly.

The Swedish survey showed the network had its dark side.“Face-booking may become an unconscious habit. A majority of the respondents(受访者) log in every time they start their web browser(浏览器). This may even develop into an addiction,” says Leif Denti, doctoral student of Psychology at the University of Gothenburg.

People with low income and low-educated individuals spend more time on Facebook. Women are generally more active than men on Facebook. Users with low income and low education use Facebook more than other groups. Within these groups，users who spend more time on Facebook also report feeling less happy and less content with their lives.

The other surprise about the network is that although a huge amount of personal “ news”is traded through the site,it tends to focus on the positive.“ Most of the content they share has something to do with major events, positive events and when feeling good,”says Leif Denti.

2 . When he was two years old, Ben stopped seeing out of his left eye. His mother took him to the doctor and soon discovered he had cancer in both eyes. After possible treatments failed, doctors removed both his eyes. For Ben, vision was gone forever.

But by the time he was seven years old, he had developed a technique for feeling the world around him: he clicked with his mouth and listened for the returning echoes. This method enabled Ben to determine the locations of open doorways, people, parked cars, garbage cans, and so on. He was echolocating: bouncing his sound waves off objects in the environment and catching the reflections to build a mental model of his surroundings.

Echolocation may sound like an improbable feat for a human, but thousands of blind people have perfected this skill, just like Ben did. The event has been written about since at least the 1940s, when the word ''echolocation" was first invented in a science article titled “Echolocation by Blind Men , Bats, and Radar.”

How could blindness give rise to the amazing ability to understand the surroundings with one's ears? The answer lies in a gift on the brain; huge adaptability.

Mother Nature filled our brains with flexibility to adapt to circumstances. Just as sharp teeth and fast legs are useful for survival, so is the brain's ability to reset, which allows for learning, memory, and die ability to develop new skills.

In Ben's case, his brain's flexible wiring repurposed his visual cortex for processing sound. As a result, Ben had more neurons available to deal with listening information, and this increased processing power allowed Ben to interpret soundwaves in shocking detail. Ben's super-hearing proves a more general rule: the more brain area a particular sense has, the better it performs.

3 . Located in the southeast of Canada and with a population of approximately 6 million, Toronto is a big and beautiful city, which has developed from a relatively unknown place over the past half century to the center of culture, trade and communication in Canada.

With its colorful ethnic mix, rich history and breathtaking buildings. Toronto offers non-stop adventures to the tourists. To get a sense of how big, various and magical Toronto is, the best place to start is the CN Tower. From this point, visitors can get a bird's-eye view of the city's amazing scenery and unique geography.

In addition to being an important center of culture, trade and communication in Canada, Toronto is also a major muti-ethnic city. It is the most populous city in Canada and its citizens come from countries around the world and from different kinds of ethnic backgrounds. Every day, in most places of the city, a hundred different languages can be heard on the streets, from Hindi to Greek to French. This, perhaps, explains why former Prime Minister Pierre Trudeau once said that Canada is a mosaic（嵌合体）of cultures and languages rather than a melting pot.

Street signs in Toronto are mostly in English. Weekly and daily newspapers are published in various languages, and the city hosts the successful international film festival each September. It is also home to a popular baseball team the Toronto Blue Jays. Toronto has something for everyone.

Moreover, Toronto has been rated one of the most livable cities in the world by United Nations Human Settlements Programme for many years. At the same time, Toronto is one of the safest, richest cities in the world with the highest standard of living.

4 . Online Bachelor's Degrees and Programs

The overview

Colleges offer online degrees in a range of fields. Click on a degree program to explore what courses you take, how long the program takes to complete, career options and average salary. For example, to earn an online health science bachelor's degree, you would take courses in public health, health communications and epidemiology(流行病学).

The benefits

Pursuing an accredited(官方认可的)online bachelor's degree can help you take the next step in your career. Through your program, you'll attend online lectures, study from home manage a busy schedule and interact virtually with professors and classmates.

The applicants

An online college degree may appeal to those who want more flexibility in completing their education, or who want to take classes while working full time or parenting. Choosing where to register online will likely be challenging, but below you'll find tools, advice and other resources to make your search easier.

Best online bachelor's programs

U. S. News evaluated several factors to rank the best online bachelor's degree programs, including graduation rates and support services available remotely.

To see the full ranking list, please click here.

5 . Americans are now allowed to get a COVID-19 vaccine （疫苗）. But the process in America is not going as smoothly as some had hoped. Many people are still facing a wait for their first shot. Moreover, the vaccines aren't available to kids under 16 yet. That's because scientists have only tested if the vaccine works in adults.

The good news is that there are two companies, Moderna and Pfizer, making COVID-19 vaccines. They are now running clinical trials（临床实验）to test their vaccines in teens and kids. Volunteers are given a treatment plan and then evaluated after.

Clinical trials are designed with safety in mind and usually done in adults first. They work like this: volunteers get placed into one of two groups. One group receives the vaccine. The other group gets a placebo. This is a shot given in the same way as the vaccine but with no effect. Scientists can compare the effects of the real vaccine against the placebo to see if the vaccine works. Researchers want to know everything that a person experiences when they get the shot, so they can detect any harmful effects. If anything did happen, the trial would stop immediately.

Some teens are eager to volunteer because they want to help people. Maybe you're the right age to be part of a clinical trial for the COVID-19 vaccine. Why not volunteer For A Vaccine Trial? Interested kids should read about the trials because every trial has risks. They should talk to their doctor and weigh the benefits and risks. Every vaccine has rare side effects in a few patients.

If you want to participate in a trial, you can try to sign up online by just clicking here, clinicaltrials gov. which lists every clinical trial in the US, including COVID-19 vaccine trials.

7 . TRAVEL ADVISORY

Here are a few things you should know before you take off on your next trip.

Frontier Airlines Face Covering Requirement

As required by federal law, the Centers for Disease Control (CDC) Order and Transportation Security Administration (TSA) Security Directive, all passengers and employees must wear a face covering over nose and mouth throughout the Frontier travel experience including at ticket counters, gate areas, baggage claim and onboard all flights. Face coverings are not required for children under the age of 2. Face coverings must fit snugly(紧密地) over your nose and mouth and be secured under the chin. Not wearing an approved face covering is a violation of federal law and you may lose future travel privileges on Frontier.

* Persons with a disability who cannot wear a mask, or cannot safely wear a mask, because of that disability as defined by the Americans with Disabilities Act can apply for a face mask exemption(豁免). To learn about pre-travel exemption requirements, click here.

Temperature Screening Requirement

Anyone with a temperature of 100.4 degrees Fahrenheit or higher will not be able to board the plane. If time allows, we will give customers the opportunity to rest before receiving a second check. If the second temperature screening is 100.4 degrees or higher, our team will help the customer to rebook travel on a later date when they are feeling better.

Know Your Travel Policy

CDC issued an Order on January 12, 2021(effective since January, 26, 2021) requiring proof of a negative COVID-19 test or documentation of having recovered from COVID-19 for all air passengers arriving from a foreign country to the US.