You get anxious if there's no wi-fi in the hotel or mobile phone signal up the mountain. You feel upset if your phone is getting low on power and you secretly worry things will go wrong at work if you're not there. All these can be called “always on” stress caused by smart phone addiction.

    For some people, smart phones have set them free from the nine-to-five work. Flexible working has given them more control over their working lives and enabled them to spend more time with their friends and families. For many others though, smart phones have become cruel masters in their pockets, never allowing them to turn them off and relax.

    Pittsburgh-based developer Kevin Holesh was worried about how much he was ignoring his family and friends in favor of his iPhone. So he developed an app — Moment — to monitor his usage. The app enables users to see how much time they're spending on the device and set up warnings if the usage limits are broken. “Moment's goal is to promote balance in your life,” his website explains. “Some time on your phone, some time off it enjoying your loving family and friends around you.”

    Dr. Christine Grant, an occupational psychologist at Coventry University, said, “The effects of this ‘always on' culture are that your mind is never resting, and you're not giving your body time to recover, so you're always stressed. And the more tired and stressed we get, the more mistakes we make. Physical and mental health can suffer.”

    And as the number of connected smart phones is increasing, so is the amount of data. This is leading to a sort of decision paralysis (瘫痪) and is creating more stress in the workplace because people have to receive a broader range of data and communications which are often difficult to manage. “It actually makes it more difficult to make decisions and many do less because they're controlled by it all and feel they can never escape the office,” said Dr. Christine Grant.

    One of the questions surrounding climate change is how it might affect the food supply for a growing global population. A new study suggests that researchers have been overlooking how two key human responses to climate—how much land people choose to farm, and the number of crops they plant—will affect food production in the future. The new study focused on the Brazilian state of Mato Grosso, an emerging（新兴的）global breadbasket（产粮地区）that as of 2013 supplied 10 percent of the world's soybeans. The researchers used variations in temperature and precipitation（降水）across the state over an eight-year period to estimate the sensitivity of the region's agricultural production to climate change. Those historical comparisons can help in making predictions about the sensitivity of agriculture to future climate change.

    The study found that, if the patterns from 2002 to 2008 hold in the future, an increase in average temperature in Mato Grosso of just 1 degree will lead to a 9 to 13 percent reduction in overall production of soy and corn. “This is worrisome given that the temperature in the study region is predicted to rise by 2 degrees by 2050,” said Avery Cohn, who led the study.

    Most studies of this kind look only at the extent to which climate shocks affect crop output. But researchers can miss critical dynamics（动力）that can affect overall output, says Leah VanWey, one of the study's senior authors. “If you look at output alone, you're not looking at all of the information because there are economic and social changes going on as well,” said VanWey.

    If output decreases, farmers may put less land area into production because it's not profitable. Farmers may also vary the number of crops they plant in a growing season. Double cropping is common in Mato Grosso. But if the weather is bad, farmers may change their decision to plant a second crop.

    Running your small business requires good staff. Once you find them, you don't want to let them go elsewhere.

    During an employee's time with a company, there are a number of forces that influence his or her behavior. I like to refer to them as "push" and "pull". You're either pushing an employee towards the door, or pulling them deeper into your organization.

    Suppose that you've made a good hire and you want to keep the employees, the trick is to recognize individual needs of employees and satisfy those needs, within reason, in order to keep pulling them away from the door. Even if you can't pull them away from the door, at least don't do things to push them out of the door.

    Recognize that some employees will lose interest and need something fresh to keep their interest. If you can't continually provide challenges, opportunities for promotion and other interesting and rewarding opportunities, then you'll have some employees leave through no fault of your own.

    The important thing is to identify your key employees and make certain they are being treated well. Communicate with them on a regular basis to make certain that you understand what makes them behave in a particular way, and be aware of concerns they may have about job satisfaction.

Hot Air Balloons

    The basis of how the balloon works is that warmer air rises in cooler air. This is because hot air is lighter than cool air as it has less mass per unit of volume. Mass can be defined by the measure of how much matter something contains. The actual balloon has to be large as it takes a large amount of heated air to lift it off the ground.

    The burner uses propane gas to heat up the air in the envelope to move the balloon off the ground and into the air. The pilot must keep firing the burner at regular intervals throughout the flight to ensure that the balloon continues to the stable. Naturally, the hot air will not escape from the hot at the very bottom of the envelop as firstly, hot air rises and secondly, the floating power keeps it moving up.

    To move the balloon upwards, the pilot opens up the propane value which lets the propane flow to the burner which in turn frees the flame up into the envelope. It works in much the same way as a gas grill: the more you open the valve, the bigger the flame to beat the air and the faster the balloon rises.

    The “Parachute Valve” at the very top of the balloon is what is used to bring the balloon down towards the ground. It is a circle of fabric cut out of the top of the envelop which is controlled by a rope which runs down through the middle of the envelope to the basket. If the pilot wants to bring the balloon down, he or she simply pulls on the rope which will open the valve, letting hot air escape, decreasing the inner air temperature. This cooling of air causes the balloon to slow its rise.

    The pilot can operate horizontally by changing the vertical position of the balloon because the wind blows in different directions at different altitudes. If the pilot wants to move in a particular direction, he or she simply arises and falls to the appropriate level and rides with the wind.

    In Europe, there is no escape for those who do not appreciate art and architecture(建筑). It is a heaven for people who want to feel like they have been transported to famous historical time periods from America. For me, Europe was a complete contrast from America. London and France had a more royal feel than New York, and Rome felt more ancient. I wasn't just on a different continent; it felt like I was in a different century.

    My parents and I visited London, Paris and Rome this summer in celebration of the end of my high school experience. It was supposed to be a break from a life as busy as a bee in New York, the constant stress, the crowded subway rides, and the weary body that had accompanied me for the last four years. It was an opportunity to appreciate Europe the way I couldn't do it just by reading history books.

    My favorite parts of London were the Tower of London and the Churchill War Rooms. As a site of past executions(刑场), the Tower of London displayed punishing devices from the 16^th and 17^th century and told stories of various members of the royal family who had ever been imprisoned in the tower, some even imprisoned by their own family members when they were seen as a threat to the crown. Besides that, I also got to see the royal family's crown jewels, amazingly beautiful.

    The Churchchill War Rooms, though very different from the Tower of London, were also spellbinding from a historic perspective. I am not a history fan, but I enjoy museums, and I took fancy in the Churchchill Museum inside the War Rooms that detailed the events of Churchchill's life and World War II. Everything I saw in it built up his life from his childhood to his last years, creating a three-dimensional Churchchill in my mind who was a person just like myself. He longed for more, he made mistakes, he experienced loneliness and sadness. But he had also done some remarkable things like uniting Britain during World War II.

    Our rewarding trip ended in Rome a couple of days later.

    After many considerations and years of heated argument, gray wolves were brought back to Yellowstone National Park. Fourteen wolves were caught in Canada and transported to the park. By last year, the Yellowstone wolf population had grown to more than 170 wolves.

    Gray wolves once were seen here and there in the Yellowstone area and much of the continental United States, but they were gradually displaced by human development. By the 1920s, wolves had practically disappeared from the Yellowstone area. They went farther north into the deep forests of Canada, where there were fewer humans around.

    The disappearance of the wolves had many unexpected results. Deer and elk populations — major food sources for the wolf — grew rapidly. These animals consumed large amounts of vegetation (植被), which reduced plant diversity in the park. In the absence of wolves, coyote populations also grew quickly. The coyotes killed a large percentage of the park's red foxes, and completely drove away the park's beavers.

    As early as 1966, biologists asked the government to consider reintroducing wolves to Yellowstone Park. They hoped that wolves would be able to control the elk and coyote problems. Many farmers opposed the plan because they feared that wolves would kill their farm animals or pets.

    The government spent nearly 30 years coming up with a plan to reintroduce the wolves. The U.S. Fish and Wildlife Service carefully monitors and manages the wolf packs in Yellowstone. Today, the debate continues over how well the gray wolf is fitting in at Yellowstone. Elk, deer, and coyote populations are down, while beavers and red foxes have made a comeback. The Yellowstone wolf project has been a valuable experiment to help biologists decide whether to reintroduce wolves to other parts of the country as well.