If you wear a fitness traoker, no doubt you check it throughout the day, recording your steps or checking your heart rate and congratulating yourself as you get closer to your goals. But a new study finds that your Fitbit really isn't as much of an indicator of your health and fitness as the people you hang out with.

Researchers have long known that our friends influence whether we get into not-so-healthy habits. Now scientists want to take a closer look to see if friends also influence health, as well as happiness and stress.

“We were interested in the topology of the social network — what does my position within my social network predict about my health and well-being?” said Nitesh V. Chawla; the study's lead author. “What we found was that the social network structure provided an important improvement in predictability of wellness states of a person over just using the data coming from fitness trackers.”

Participants in the study wore Fitbits so researchers could collect information about steps, heart rate, sleep data and activity level. They also completed surveys about their feelings of happiness and stress. Researchers got data about the participants' social network using a mobile software that collected information about calls and texts.

The team then analyzed the data, comparing the tracker information to the social network characteristics. The results showed a strong relation between the structure of the participants' social network and their heart rate, the number of steps they took and their daily level of activity.

The researchers suggest that one way these research results might be used is in the workplace. Employers who give workers fitness trackers to improve their health could suggest they share their progress with each other in order to build an encouraging network.

On January 22, a massive iceberg broke off from Antarctica’s Brunt Ice Shelf. Scientists say the iceberg was expected to break off and the event isn’t connected to climate change. But the size of the iceberg is hard to imagine.

The iceberg, known as “A81”, is extremely large. It covers an area of about 600 square miles (1,550 square kilometers).

Antarctica, the world’s fifth largest continent, is covered with a layer of ice and snow that’s roughly 1.2 miles (1.9 kilometers) thick. As snow falls, it piles up in the center of Antarctica in a huge layer of ice. Over time, the weight of this ice and snow creates slowly moving rivers of ice called glaciers, which push out towards the sea.

When the glaciers reach the sea, they slowly push out beyond the edge of the land, forming huge “ice shelves”, These are massive sections of ice that spread out over the sea, floating on the water below. Antarctica’s largest ice shelf, the Ross Ice Shelf, is about the size of France.

From time to time, the edges of the ice shelves break off. This is a natural process, called “calving”. Though calving events are a normal part of the ice shelf in Antarctica, one expert describes huge calving events like this one as “spectacular”,

Unlike an ice shelf, sea ice isn’t attached to Antarctica’s land. It’s a layer of ice that floats on the surface of the sea. The sea ice is there year-round. It grows larger in the cold winters, and smaller as it begins to melt in the summers.

It’s now summer in Antarctica, and scientists say the sea ice is disappearing “unusually” rapidly. Last year, with temperatures warmer than normal, Antarctica set a record for the lowest amount of sea ice ever recorded. Scientists say Antarctica’s sea ice could set a new record low again this year.

Sport is not only physically challenging, but can also be mentally challenging. Criticism (批评) from coaches, parents and other teammates, as well as pressure to win can create too much anxiety or stress for young athletes. Stress can be physical, emotional, or psychological and research has indicated that it can lead to burnout. Burnout has been described as dropping out of or quitting an activity that was at one time enjoyable.

The early years of growth are important years for learning about oneself and the sport setting is one where valuable experiences can take place. Young athletes can for example, learn how to cooperate with others, make friends, and gain other social skills that will be used throughout their lives. Coaches and parents should be aware, at all times, that their feedback to youngsters can greatly affect their children. Youngsters may take their parents and coaches’ criticisms to heart and find faults in themselves.

Coaches and parents should also pay attention that youth sport participation does not become work for children. The outcome of the game should not be more important than the process of learning the sport an other life lessons. In today’s youth sport setting, young athletes may be worrying more about who will win instead of enjoying themselves and the sport. Following a game, many parents and coaches focus on the outcome and find faults with youngsters’ performances. Positive support should be provided regardless of the outcome. Research indicates that positive support encourages and has a greater effect on learning than criticism. Again, criticism can create high levels of stress, which can lead to burnout.