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    This month, Germany's transport minister, Alexander Dobrindt, proposed the first set of rules for autonomous vehicles(自主驾驶车辆). They would define the driver's role in such cars and govern how such cars perform in crashes where lives might be lost.

    The proposal attempts to deal with what some call the “death valley” of autonomous vehicles: the grey area between semi-autonomous and fully driverless cars that could delay the driverless future.

    Dobrindt wants three things: that a car always chooses property(财产) damage over personal injury; that it never distinguishes between humans based on age or race; and that if a human removes his or her hands from the driving wheel — to check email, say — the car's maker is responsible if there is a crash.

    “The change to the road traffic law will permit fully automatic driving,” says Dobrindt. It will put fully driverless cars on an equal legal footing to human drivers, he says.

    Who is responsible for the operation of such vehicles is not clear among car makers, consumers and lawyers. “The liability(法律责任) issue is the biggest one of them all,” says Natasha Merat at the University of Leeds, UK.

    An assumption behind UK insurance for driverless cars, introduced earlier this year, insists that a human “ be watchful and monitoring the road” at every moment.

    But that is not what many people have in mind when thinking of driverless cars. “When you say ‘driverless cars', people expect driverless cars.”Merat says. “You know — no driver.”

    Because of the confusion, Merat thinks some car makers will wait until vehicles can be fully automated without operation.

    Driverless cars may end up being a form of public transport rather than vehicles you own, says Ryan Calo at Stanford University, California. That is happening in the UK and Singapore, where government-provided driverless vehicles are being launched.

    That would go down poorly in the US, however. “The idea that the government would take over driverless cars and treat them as a public good would get absolutely nowhere here,” says Calo.

    Charlotte Heffelmire was home in Vienna,Va.,for Thanksgiving break from the Air Force Academy when she saw that her father had gotten stuck under the pickup truck he'd been working on.

    "I was on my back,face up,and I was trying to get some brake lines when apparently the jack（千斤顶）slipped and fell down on me,"her dad,Eric Heffelmire,told WUSA9.Gasoline spilled（溢出）and caught fire,and he knew he was in trouble."I thought they 'd be pulling out a dead body later in the evening."

    After his struggling for 10 minutes,his barefoot teenage daughter came running into the garage."I felt the weight shift,and I said,'You almost got it.'and then it was just UGHHHRRR,and suddenly I'm pulled out,"Eric told NBC4.

    Even Charlotte,120 pounds and 5-foot-6,isn't sure where her power came from."It was some crazy strength, "she told WUSA9.

    Realizing the burning truck could set her house on fire at any moment,Charlotte jumped into the truck and drove it out of the garage."I didn't want the entire house to explode with the truck,so I started the truck,put it in four-wheel drive,and managed to drive it with three wheels,"she said.

    Then she went inside the house to grab her baby sister and got her grandmother out of the house too."I just did what I had to do,so I don't feel like a big hero or anything,"Charlotte said.Her local fire department,Fairfax County Fire and Rescue,felt differently,awarding her the Citizen Lifesaving Award.

    Why should mankind explore space? Why should money, time and effort be spent exploring and researching something with so few apparent benefits? Why should resources be spent on space rather than on conditions and people on Earth? These are questions that, understandably, are very often asked.

    Perhaps the best answer lies in our genetic makeup as human beings. What drove our ancestors to move from the trees into the plains, and on into all possible areas and environments? The wider the spread of a species, the better its chance of survival. Perhaps the best reason for exploring space is this genetic tendency to expand wherever possible.

    Nearly every successful civilization has explored, because by doing so, any dangers in surrounding areas can be identified and prepared for. Without knowledge, we may be completely destroyed by the danger. With knowledge, we can lessen its effects.

    Exploration also allows minerals and other potential resources to be found. Even if we have no immediate need of them, they will perhaps be useful later. Resources may be more than physical possessions. Knowledge or techniques have been acquired through exploration. The techniques may have medical applications which can improve the length or quality of our lives. We have already benefited from other spin-offs including improvements in earthquake prediction, in satellites for weather forecasting and in communications systems. Even non-stick pans and mirrored sunglasses are by products(副产品) of technological developments in the space industry!

    While many resources are spent on what seems a small return, the exploration of space allows creative, brave and intelligent members of our species to focus on what may serve to save us. While space may hold many wonders and explanations of how the universe was formed or how it works, it also holds dangers. The danger exists, but knowledge can help human beings to survive. Without the ability to reach out across space, the chance to save ourselves might not exist.

    While Earth is the only planet known to support life, surely the adaptive ability of humans would allow us to live on other planets. It is true that the lifestyle would be different, but human life and cultures have adapted in the past and surely could in the future.

A Different Kind of Spring Break

    For many American university students, the week-long spring break holiday means an endless part on a sunny beach in Florida or Mexico. In Panama City Beach, Florida, a city with a permanent population of approximately 36,000, more than half a million university students arrive during the month of March to play and party, making it the number one spring break destination in the United States.

    A week-long drinking binge is not for everyone, however, and a growing number of American university students have found a way to make spring break matter. For them, joining or leading a group of volunteers to travel locally or internationally and work to address problems such as poverty, homelessness, or environmental damage makes spring break a unique learning experience that university students can feel good at.

    During one spring break week, students at James Madison University in Virginia participated in 15 "alternative spring break" trips to nearby states, three others to more distant parts of the United States, and five international trips. One group of JMU students traveled to Bogalusa, Louisiana, to help rebuild homes damaged by Hurricane Katrina. Another group traveled to Mississippi to organize creative activities for children living in a homeless shelter. One group of students did go to Florida, but not to lie on the sand. They performed exhausting physical labor such as maintaining roving invasive plant species that threaten the native Florida ecosystem.

    Students who participate in alternative spring break projects find them very rewarding. While most university students have to get their degrees before they can start helping people, student volunteers are able to help people now. On the other hand, the accommodations are far from glamorous. Students often sleep on the floor of a school or church, or spend the week camping in tents. But students only pay around $250 for meals and transportation, which is much less than some of their peers spend to travel to more traditional spring break hot spot.

    Sometimes the best gift is the one you can use at home. These items will likely be appreciated all year for time spent relaxing, entertaining or getting things done.

    Jawbone Jambox Wireless Speaker

    $199 retail (far cheaper online). The bigger version goes for $299.

    The cool-looking rechargeable wireless speaker is getting good reviews for its big, balanced sound and compact design. It lets you stream music from smartphones, laptops and other Bluetooth devices(设备).

    Chalkboard Wall Planter

    $129. 95 retail at Williams-Sonoma

    No need to make room indoors for more flower pots. Grow a herb garden indoors in a wall-fixed vertical planter, and you'll get the benefits of fragrance (芳香). Fill the 10 planting cells with the herbs of your choice, and hang the planter in a sunny spot. Use the chalkboard borders to label each plant. Measures 16 by 5 by 24 inches and weighs 11 pounds.

    Pocket Projector

    $299 retail at Brookstone

    Let everyone get a good look at the pictures on your smartphone, computer, video player, or digital camera. This rechargeable pocket projector can turn a flat surface into a 60-inch big screen with 1080p HD picture quality. Invite friends for a movie night or a presentation. An HDMI cable is included to connect it to your device.

    Adjustable Tablet Stand

    $159 at Sharper Image

    This is the gift for the person who enjoys mobile. Use it to keep your hands free while doing homework, crafts or writing out bills. It can be rotated through 360 degrees. The stand slides easily under your furniture and can be used on either side of a bed or a sofa. It also folds for storage.

A new study examines possible harm caused by microscopic pieces of plastic that end up inside people's bodies. These materials -known as microplastics and nanoplastics - can enter the body through the air or in food or drinks.

One new study suggests the buildup of such plastics inside the body can increase the risk of a stroke, heart attack or death. But the researchers noted the evidence presented cannot prove a direct link between tiny plastic materials and heart problems.

The study involved 257 people who had medical operations to clear blocked blood vessels （血管） in their necks. Italian researchers examined the fatty buildup the doctors removed from the carotid arteries, which supply blood and oxygen to the brain. Using two methods, they found evidence of plastics-mostly nanoplastics that cannot be seen-in the artery plaque（动脉斑块）of 150 patients. No evidence of plastics was seen in 107 patients.

The team followed these people for three years. During that time, 30 individuals, or 20 percent of the group with plastics, had a heart attack, stroke, or died from any cause. These rates dropped to about eight percent among those with no evidence of plastics. Research results were recently published in a study in the New England Journal of Medicine.

The researchers admitted their study was very small. For example, it only looked at people with narrowed arteries who were already at risk for heart attacks and stroke.

Steve Nissen is a heart expert at the Cleveland Clinic in the state of Ohio who was not part of the study. He told the Associated Press he thinks the team's estimate that the risk of heart attack, stroke or death was four times greater seems too high. "It would mean that these microplastics are the most important cause of coronary heart disease （冠心病） yet discovered. And I just don't think that's likely to be right," Nissen said. "Maybe, it's just a wake-up call that perhaps we need to take the problem of microplastics more seriously." Nissen added.