Nuclear power's danger to health, safety, and even life itself can be summed up in one word: radiation.

    Nuclear radiation has a certain mystery about it, partly because it cannot be detected by human senses. It can't be seen or heard, or touched or tasted, even though it may be all around us. There are other things like that. For example, radio waves are all around us but we can't detect them, sense them, without a radio receiver. Similarly, we can't sense radioactivity without a radiation detector. But unlike common radio waves, nuclear radiation is not harmless to human beings and other living things.

    At very high levels, radiation can kill an animal or human being immediately by killing masses of cells in vital organs. But even the lowest levels can do serious damage. There is no levels of radiation that is completely safe. If the radiation does not hit anything important, the damage may not be serious. This is the case when only a few cells are hit, and if they are killed immediately. Your body will replace the dead cells with healthy ones. But if the few cells are only damaged, and if they reproduce themselves, you may be in trouble. They can grow into cancer. Sometimes this does not show up for many years.

    This is another reason for some of the mystery about nuclear radiation. Serious damage can be done without the victim being aware at the time that damage has occurred. A person can be irradiated(辐射)and feel fine, then die for cancer five, ten, or twenty years later as a result. Or a child can be born weak as a result of radiation absorbed by its grandparents.

    Radiation can hurt us. We must know the truth.

    Daylight-powered germ-killing equipment（杀菌设备）may someday help protect health workers from deadly virus like Ebola virus. That is a finding from a study published in the journal Science Advances.

    Study organizers say they've developed membranes（薄膜）that produce very small amounts of hydrogen peroxide（过氧化氢）when left in daylight. Membranes are thin plastic, structures that can serve as barriers. They let some things pass through, but other things art blocked. Hydrogen peroxide, a liquid sold in drug stores, works as a disinfectant（杀菌剂）.

    Nearly 500 health workers were infected and died in 2014 when Ebola spread through parts of West Africa. Caregivers wear full-body protective suits when they come into contact with patients with infectious diseases. But the process of removing the suits is a time when infection can spread if the surface is covered with virus. “If there's any live bacteria or virus on the surface, it's still transmissible and could cause infection,” said Gang Sun of the University of California. He is one of the researchers that worked to develop membranes that could cover the outside of protective equipment.

    When the chemical molecules（分子）on the surface of these membranes are put in sunlight, they react with oxygen in the air to produce small amounts of hydrogen peroxide. Gang Sun explains that the process creates less hydrogen peroxide than what you would use to remove dirt on clothing, for example. But it is still enough to kill organisms.

    Rohan Tikekar is a food scientist with the University of Maryland. He described the development as “quite novel,” or new and different, Tikekar was not involved with the recent study. He said others have developed materials that produce disinfecting chemicals. But most only work under high-energy ultraviolet（U V）light, and not usual daylight. The new membrane also works in the dark for at least an hour or two because of chemical properties that can recharge its germ-killing powers. Tikekar called that an important improvement.

    Gang Sun said the new membranes, though still Far from perfect could be used for things other than protective equipment for health workers. They could also be added to packaging for fruits and vegetables to keep foods fresher and reduce the risk of being polluted. Some versions of the material use natural chemicals' Sun says that one of the next steps is to make it safe to sat

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.

    Kang Sung-il buys Sancho, his Pomeranian, a toy every business trip and this lunar New Year holiday will dress him up in s new $50 suit to visit 'grandma', Kang's mother. Kang and his wife say children are too expensive and bring too much pressure. Instead they have chosen to shower Sancho with love and gifts.

    They are not alone. South Korea's pet industry is booming, fuelled by the same factors that have made the country's birth rate, at 1.05 births per woman, the lowest in the world: the high cost of education and housing as well as extremely long working days.

    "Social pressures in South Korea are such that parents are required to provider resources for decades from private schooling to art classes," said Kang a 39 year old manager of a pet funeral home.

    On top of education expenses, an average and household must budget roughly 12.8 years of income to buy a mid-range home, compared to 8.8 years in 2014, data from KB Kookmin Bank shows. Adding to their stress, south Koreans work the third most hours per year among OECD (经合组织) nations, next only to Mexico and costa Rica.

    Pet-owning households have rose to 28 percent of all South Korean households in 2018, compared with 18 percent in 2012, government data shows.

    That in turn has resulted in a prosperous pet care industry whose offerings include tailored pet diets and high-priced photo shoots. Pet-related startup s are also popular with venture capitalists. The south Korean pet-related industry was worth 2.7 trillion won ($2.4 billion) last year, and that could more than double in size by 2027, according to the Korean Rural Economic Institute.

    American high school students are terrible writers, and one education reform group thinks it has an answer: robots. Or, more accurately, robot-readers—computers programmed to scan students' essays and spit out a grade.

    Mark Shermis, professor of the College of Education at the University of Akron, is helping to hold a contest, set up by the William and Flora Hewlett Foundation (WFHF), which promises $ 100,000 in prize money to programmers who write the best automated grading software. "If you're a high school teacher and you give a writing task, you're walking home with 150 essays," Shermis said. "You're going to need some help."

    Automated essay grading was first proposed in the 1960s, but computers back then were not up to the task. In the late 1990s, as technology improved, several textbooks and testing companies jumped into the field. Today, computers are used to grade essays on South Dakota's student writing assessments and a handful of other exams, including the TOEFL test of English fluency, taken by foreign students.

    The Hewlett contest aims to show that computers can grade as well as English teachers—only much more quickly and without all that depressing red ink. "Automated essay scoring is objective," Shermis said. "And it can be done immediately. If students finish an essay at 10 pm, they will get a result at 10: 01 pm."

    Take, for instance, the Intelligent Essay Assessor, a web-based tool marketed by Pearson Education, Inc. Within seconds, it can analyze an essay for spelling, grammar, organization, and help students to make revisions. The program scans for key words and analyzes semantic (语义的) patterns, and Pearson claims that it can understand the meaning of text much the same as a human reader.

Where does the meat on our table come from? It usually comes from livestock like chickens and cows. But did you know that meat can also be made in a lab? US company JUST has announced that lab-grown meat could be on some restaurant menus in the United States and Asia by the end of 2018, The Independent reported.

"These meats include chicken nuggets (鸡块), sausage and foie gras (鹅肝酱)," Josh Tetrick, CEO of JUST, told The Independent. Lab meat is sometimes referred to as "clean meat". It is made using the stem cells (干细胞) of living livestock. The cells need to be grown in a lab for a few weeks. For example, making a hamburger patty (肉饼) takes about nine weeks, CNN reported. This is faster than raising a cow, which usually takes over 20 weeks.

The first clean meat was a beef burger that was produced in 2013, but it was said to taste quite dry. How does clean meat taste now? Clean meat supporters told CNN that they think it tastes just like traditional meat.

Clean meat has other advantages. It is healthier than traditional meat. Meat producers can control what type of fat goes into the meat. They can produce clean meat that contains healthy fats, such as omega-3 fatty acids (脂肪酸). This kind of fat is good for people's hearts.

Clean meat can also help to solve global warming. According to The Washington Post, about 14.5 percent of the planet's greenhouse gas emissions (排放) come from raising livestock. That's more than the emissions from every car, train, ship and airplane in the world combined. It is predicted that switching to clean meat could lower greenhouse gas emissions by 96 percent, The Independent reported.