By the mid-nineteenth century, the term “icebox” had entered the American language, but ice was still only beginning to affect the diet of ordinary citizens in the United States. The ice trade grew with the growth of cities. Ice was used in hotels, pubs, and hospitals, and by some forward-looking city dealers in fresh meat, fresh fish, and butler. After the Civil War (1861-1865), as ice was used to refrigerate freight cars(货车), it also came into household use. Even before 1880, half the ice sold in New York, Philadelphia, and Baltimore, and one-third of that sold in Boston and Chicago, went to families for their own use. This had become possible because a new household convenience, the icebox, a precursor（前身）of the modem refrigerator, had been invented.

    Making an efficient icebox was not as easy as we might now suppose. In the early nineteenth century, the knowledge of the physics of heat, which was essential to a science of refrigeration, was undeveloped. The common belief that the best icebox was one that prevented the ice from melting was of course mistaken, for it was the melting of the ice that performed the cooling. Nevertheless, early efforts to economize ice included wrapping the ice in blankets, which kept the ice from doing its job. Not until near the end of the nineteenth century did inventors achieve the delicate balance of insulation(绝缘) and circulation needed for an efficient icebox.

    But as early as 1803, an intelligent Maryland farmer, Thomas Moore, had been on the right track. He owned a farm about twenty miles outside the city of Washington, for which the village of Georgetown was the market center. When he used an icebox of his own design to transport his butter to market, he found that customers would pass up the rapidly melting butter of his competitors to pay an extra price for his butter, still fresh and hard in neat, one-pound bricks. One advantage of his icebox, Moore explained, was that fanners would no longer have to travel to market at night in order to keep their produce cool.

    The Internet plays a big part in human life. We use it for work and pleasure. We use it to learn a new language. We find advice on it. We use it to connect with family and friends. We use it to stay in touch with events we care about. The list goes on and on.

    As far as the Internet being a part of our lives. - Well, that train has left the station. This expression means there is no going back to an Internet-free life. But can using the Internet too much be bad for our health? It might be, say researchers. A new study finds that heavy Internet use may be connected to high blood pressure (血压) in a young group: teenagers.

    The study results show that teens who spend at least 14 hours a week only may cause high blood pressure, which makes your heart and blood vessels (血管) work too hard. Over time, this extra pressure increases your risk of a heart attack. High blood pressure can also cause heart and other diseases.

    The Henry Ford Hospital in Detroit, Michigan did the study. 335 young people, from 14 t0 17 years old, took part in it. 134 0f the teens were described as "heavy Internet users". And researchers found that out of these 134 teens, 26 had high blood pressure. The researchers say the study is the first to connect heavy web use with high blood pressure.

    The lead researcher is Andrea CassidyBushrow. She said, "Using the Internet is part of our daily life, but it shouldn't ruin us." Ms. Cassidy-Bushrow adds that it is important for teens to take regular breaks from their computers or smartphones and do some kind of physical activity. She also suggests that parents shouldn't let their children use the Internet for more than two hours a day, five days a week.

    We're Hiring Shift Workers for Our Production Plant

    Looking for a career with a company that values its employees, and promotes them from within? Then Black Cat Blades is the company for you!

    Cutting Operators

    CNC Operators

    Heat Treat Operators

    Full training provided, starting at $14.50 per hour, with the potential to move to $18.16 in one year.

    We also require a Skilled Welder(焊接工), to work 12-hour rotating shifts (轮班) in our cutting department. The successful candidate must be a registered journeyman(熟练工) within the Province of Alberta or with a Red Seal.

    We offer a great benefit package, including health and RRSPs(注册退休储蓄计划). Desirable welfare: Profit Sharing, Pay for Years of Service, Fitness Program Allowance, and fun social events for you and your family.

    Apply in person, and we'll take you on a tour of our production equipment or forward your personal information by fax or e-mail.

Black Cat Blades Ltd

    HR@ blackcatblades.com

    5604-59 St. , Edmonton, AB T6B 3C3

    Fax:

    HONG KONG-Cross-border buses operated by Hong Kong companies on Friday started trial runs on the Hong Kong-Zhuhai-Macao Bridge (HZMB) in preparation for the bridge's upcoming opening.

    "The trial runs, arranged by the governments of the Chinese mainland, the Hong Kong Special Administrative Region (SAR) and the Macao SAR, would last for three days and aimed at testing the readiness of boundary crossing facilities (设施) of the three places," the Hong Kong SAR government's Transport and Housing Bureau told Xinhua.

    Two major cross-boundary coach trade associations in Hong Kong were invited to send buses and members to participate in the trial runs.

    Freeman Cheung, secretary of Hong Kong Guangdong Boundary Crossing Bus Association, said his association would run one bus with about 10 passengers on Friday and Saturday respectively as part of the trial runs.

    "Our bus started at noon from the Hong Kong Boundary Crossing Facilities and ran all the way to Zhuhai in about 40 minutes," he said, adding that "the journey was smooth."

    Alan Chan, secretary of another trade association who participated in the trial runs as a passenger, said the clearance procedures at boundary crossing facilities of the three places all went on well and smoothly.

    "The boundary crossing facilities of Zhuhai and Macao, in particular, are operated in a collaborative (合作的) way, which helps remarkably shorten the time needed for the clearance procedures," he said.

    The HZMB, situated at the waters of Lingdingyang of Pearl River Estuary, is a mega-size sea crossing linking the Hong Kong SAR, Zhuhai city of Guangdong Province and the Macao SAR.

    The 55-km bridge is the longest bridge-and-tunnel (隧道) sea crossing in the world.

    The bridge is meant to meet the demand of passenger and freight land transport among Hong Kong, the Chinese mainland and Macao, and to establish a new land transport link between the east and west banks of the Pearl River.

WELCOME AND ARRIVAL INFORMATION

    Welcome to Harvard University Housing and thank you for choosing to live with us. To help you make a smooth transition, please read the information below on planning your arrival.

    Pets

    Dogs living with you in your pet-friendly apartment must be vaccinated for rabies and licensed with the City of Cambridge every year.

    International Students

    Consider unlocking your phone prior to leaving your home country. This will enable you to use a SIM card from a company such as campus SIMS or US Mobile in your phone after you arrive. Those sim cards may be available at the Property Management Office.

    Driving

    If you plan on bringing a moving van or truck it will not fit under the overpasses on Soldiers Field Road and Memorial Drive. Plan your route in advance to avoid a risky and costly problem.

    Parking arrangements for trucks and vans must be made in advance as well. Visit your property page for information about parking your car.

    Furniture and Lighting

    Most HUH units have no furniture—the unit is empty except for a stove and a refrigerator. You need to bring, buy, or rent a bed, other furniture, and household items. In many HUH units, rooms do not have overhead lights, so you also may need table or floor lamps.

    If you want to stock up on groceries and some household items as soon as you arrive, please find information about "Grocery Shopping" by selecting it from the drop-down menu.

    Do you suppose Darwin, one of the greatest scientists of all time, really did foolish experiments? Or did he do experiments that were so simple and basic that other people just thought they were foolish?

    Sometimes, people think they already know the answer to a question or the solution to a problem. Sometimes, they really do know an answer or a solution, but without thinking they are important.

    Charles Darwin didn't settle for(满足于) just thinking he knew something. And, he believed all things could be important however simple they seemed to be.

    Suppose you drop sheets of paper that are of exactly the same size and shape. If you drop them at the same time in the same place, they will fall in the same way. Now make one of the sheets of paper into a tight little ball and let it drop along with the other sheets. What happens? You have done an experiment that is so simple that you might think it couldn't be worth anything.

    But this simple experiment is important. It explains part of our present-day understandings of physics, ideas that were worked out long ago by Galileo and Newton. And these understandings set aside some of ancient Greek physics.

    Scientists sometimes stop to look at very simple things and to think very hard about them. Even the simplest idea, which we might think is foolish, can shake the foundations of science.