Using too much water or throwing rubbish into our rivers are clear ways that humans can put our water supply in danger , but we also affect our water supply in less obvious ways. You may wonder how paving(铺砌) a road can lead to less useable fresh water. A major part of the water we use every day is groundwater. Groundwater does not come from lakes or rivers. It comes from underground. The more roads and parking lots we pave ，the less water can flow into the ground to become groundwater.

    Human activity is not responsible for all water shortages(短缺). Drier climates are of course more likely to have droughts(干旱) than areas with more rainfall, but in any case, good management can help to make sure there is enough water to meet our basic needs.

    Thinking about the way we use water every day can make a big difference, too In the United States , a family of four can use 1.5 tons of water a day! This shows how much we depend on water to live, but there's a lot we can do to lower the number.

    You can take steps to save water in your home. To start with use the same glass for your drinking water all day. Wash it only once a day. Run your dishwasher (洗碗机)only when it is full 。Help your parents fix any leaks in your home. You can even help to keep our water supply clean by recycling batteries instead of throwing them away.

    No one enjoys hearing the sound of someone else chewing their food. Most of the time, though, it's not that big a deal but a minor annoyance.

    But for a small group of people with misophonia (恐音症), the sound can be painful, causing extreme anger and deep discomfort. The most ordinary sounds of chewing and breathing can drive them crazy. Past attempts to explain the causes of misophonia have suggested everything from compulsive disorder to an easily-annoyed personality—but according to a study published yesterday in the journal CurrentBiology, the true criminal is the structure of the brain.

    For the study, a team of researchers led by Newcastle University neuroscientist Sukhbinder Kumar recruited (招募) 42 volunteers, of whom around half had extreme misophonia and the other half served as the control group, and played them several different noises: some ordinary; some harsh, like the sound of a person screaming; and some that were ordinary for the control group but known to be annoying for misophonics, people with misophonia, like the sound of breathing. As the participants listened, the researchers monitored them for signs of anxiety, both physical symptoms and behavioral expressions, and observed their brain activity using FMRI scans.

    The only significant difference in reaction between the two groups happened, during the misophonia-specific sounds, when those with the condition showed physical changes that suggested they were entering fight-or-flight mode.

    Misophonics had increased activity in the AIC, an area known to play a central role in the system that determines which things we should pay attention to. When the trigger sounds were played, there was not only more activity in this region but also abnormally high levels of connection to other regions.

    Misophonia, in other words, may be a result of misplaced attention the brain of a misophonic focuses on things that other people normally tune out (不予理会). On a related note, on behalf of misophonics and manners-minded moms everywhere: Please, chew with your mouth closed.

    This activity will melt away the pounds, build your body and leave you on an emotional high. Yet the form of exercise, the fitness trend of the year, does not require gym membership or a personal trainer. All you need to do is walk.

    “Walking is a refreshing alternative to complicated aerobic ( 氧) routines and overpriced gym membership,” says personal trainer Lucy Knight, author of a new book on the exercise. “It is free, enjoyable and already a part of everyday life. All you need to do is correct your technique, walk faster and for longer and you will lose weight.”

    There is much evidence of the benefits of walking. Scientists at the University of Pittsburgh recently discovered that overweight people who walked briskly ( 快) for 30 to 60 minutes a day lost weight even if they didn't change any other lifestyle habits. Another American study found that people who walked for at least four hours a week gained less weight than couch potatoes as they got older. Researchers at the University of Massachusetts medical school found that people who walked every day had 25 percent fewer colds than those who sat a lot. Best of all, walking makes you feel good about yourself. “For people suffering from depression, walking three to four times a week for 30 minutes has been shown to lift their mood,” says Knight.

    But how to walk your way to weight loss and wellness? Health experts recommend that we should walk 10,000 steps a day to stay healthy. Actually you would probably need to walk at least 16,000 steps a day to lose weight. “Your workout plans depend on your level of fitness. You should aim to progress by increasing your walking time by five minutes every two weeks, and walk a bit faster. In just three months, the results should speak for themselves,” says Knight.

    An idea that started in Seattle's public library has spread throughout America and beyond. The concept is simple: help to build a sense of community in a city by getting everyone to read the same book at the same time.

    In addition to encouraging reading as a pursuit (追求) to be enjoyed by all, the program allows strangers to communicate by discussing the book on the bus, as well as promoting reading as an experience to be shared in families and schools. The idea came from Seattle librarian Nancy Pearl who launched (发起)the "If All of Seattle Read the Same Book" project in 1998. Her original program used author visits, study guides and book discussion groups to bring people together with a book, but the idea has since expanded to many other American cities, and even to Hong Kong.

    In Chicago, the mayor(市长)appeared on television to announce the choice of To Kill a Mockingbird as the first book in the "One Book, One Chicago" program. As a result, reading clubs and neighbourhood groups sprang up around the city. Across the US, stories emerged of parents and children reading to each other at night and strangers chatting away on the bus about plot and character.

    The only problem arose in New York, where local readers could not decide on one book to represent the huge and diverse population. This may show that the idea works best in medium-sized cities or large towns, where a greater sense of unity(一致)can be achieved. Or it may show that New Yorkers rather missed the point, putting all their energy and passion into the choice of the book rather than discussion about a book itself.

    Ultimately as Nancy points out, the level of success is not measured by how many people read a book, but by how many people are enriched by the process or have enjoyed speaking to someone with whom they would not otherwise have shared a word.

A recent study has found that using wood for construction instead of concrete (混凝土) and steel can reduce emissions (排放). But Tim Searchinger at Princeton University says many of these studies are based on the false foundation that harvesting wood is carbon neutral (碳中和). "Only a small percentage of the wood gets into a timber (木料) product, and a part of that gets into a timber product that can replace concrete and steel in a building," he says. Efficiencies vary in different countries, but large amounts of a harvested tree are left to be divided into parts, used in short-lived products like paper or burned for energy, all of which generate emissions.

In a report for the World Resources Institute, Searchinger and his colleagues have modelled (塑造) how using more wood for construction would affect emissions between 2010 and 2050, accounting for the emissions from harvesting the wood. They considered various types of forests and parts of wood going towards construction. They also factored in the emissions savings from replacing concrete and steel.

Under some circumstances, the researchers found significant emissions reductions. But each case required what they considered an unrealistically high portion (份额) of the wood going towards construction, as well as rapid growth only seen in warmer places, like Brazil. In general, they found a large increase in global demand for wood would probably lead to rising emissions for decades. Accounting for emissions in this way, the researchers reported in a related paper that increasing forest harvests between 2010 and 2050 would add emissions equal to roughly 10 percent of total annual emissions.

Ali Amiri at Aalto University in Finland says the report's conclusions about emissions from rising demand are probably correct, but the story is different for wood we already harvest. "Boosting the efficiency of current harvests and using more wood for longer lived purposes than paper would cut emissions," he says. "We cannot just say we should stop using wood."