My teenager son Karl became withdrawn after his father died. As a single parent, I tried to do my best to talk to him. But the more I tried, the more he pulled away. When his report card arrived during his junior year, it said that he had been absent 95 times from classes. In this way he would never graduate. I sent him to the school adviser, and I even begged him. Nothing worked.

    One night I was at work when I got a phone call. A man introduced himself as a head teacher, “I want to talk to you about Karl's absences (缺席).” Before he could say another word I choked up (硬咽), and said sadly, “I love my son. I've tried everything to get Karl to go back to school and nothing has worked. It's out of my hands.” For a moment there was silence on the other end of the line. The head teacher seriously said, “Thank you for your time.”

    Karl's next report card showed a marked improvement in his grades. He was even on the list of the best students at school. In his fourth year, I took part in a parent-teacher meeting. I noticed that his teachers were surprised at the way he had turned himself around. On our way home, he said, “Mum, remember that call from the head teacher last year?” I nodded. “That was me. I thought I'd play a joke but I heard you said. It really hit me how much I was hurting you. That's when I knew I had to make you proud.”

    It may appear strange to hear that crops are making headlines.But this is no ordinary produce—these fruits and vegetables have been grown in simulated（模拟的）Martian and lunar soils!

    Though the possibility of growing crops in outer space only gained widespread interest after Matt Damon grew potatoes in the movie "The Martian",scientists have been testing the idea for many years.Fresh produce will after all be the key to setting up space colonies（殖民地）.

    Among the pioneers in this effort is a team led by Wieger Wamelink,a scientist at Netherland's Wageningen University.In 2013,they planted fourteen varieties of plants in simulated Martian and lunar soils.Though the "Mars" plants did not bear any produce,they grew better than the "lunar" plants,most of which died shortly after being planted.Lack of vapor in the soil,according to the scientists,might have accounted for the failure.

    The second experiment began in late 2015.The researchers selected the same crops,while this time they used larger containers and added grass to them.In March 2016,their efforts were rewarded with a variety of produce including the vegetable that kept "The Martian" alive: potatoes.

    However,the researchers were still not sure if the produce was safe to eat.That's because the Martian and lunar soils contain heavy metals like lead and arsenic,which do not affect plants but are poisonous to humans.

    After months of testing,earlier this week,the team finally confirmed that the produce was safe for human consumption.Some of the crops even contained lower levels of heavy metals than plants grown in the "ordinary" earth soil.

    To celebrate the success,the scientists held a dinner party that centered ground the crops.While there is no word on how the food tasted,it sure looks delicious.

    As the temperature rises, sweaty humans are making a response that is further worsening the problem of climate change. At present, the world just has 1.6 billion air conditioning units, but these units use a surprising total of ten percent of all global electricity supply. While less than a third of families globally are so equipped, the most AC-addicted countries are Japan (in 91 percent of families), the US (90 percent) and South Korea(86 percent).

    New research by the International Energy Agency (IEA) guesses that the total number of AC units is likely to increase to over 5.6 billion by 2050－equal to ten new units being sold every second for more than 30 years－with sales driven particularly by India, China and Indonesia. This will make the use of air conditioning one of the world's largest demands for energy.

    "Growing electricity demand for air conditioning is one of the most critical blind spots in today's energy debate," argues Faith Birol, executive director of the IEA. "With rising incomes, air conditioner ownership will skyrocket, especially in the developing world. While this will improve daily lives, it is quite necessary that efficiency performance be prioritized."

    Birol and the IEA stress the need for new efficiency standards to ensure that consumers are at least buying units that require significantly less power to function, therefore decreasing the total energy demand. Variations on the traditional "vapor compression" technology, which has formed the basis for AC units for more than a century, may appear really important. A water-based system was recently developed by researchers at the National University of Singapore (NUS), which uses 40 percent less electricity and produces only one by-product: drinkable water.

    "Our cooling system can be tailored for all types of weather conditions, from wet climate in the tropics to dry climate in the deserts," says associate professor Ernest Chua at NUS. "While it can be used for indoor living and commercial spaces, it can also be easily used to provide air conditioning for blocks of buildings in an energy-efficient manner."

Volunteer Chances for Teens

    About Learning Buddies

    Learning Buddies is an education program for K-5 students at the Beacon Hill, Columbia, Douglass-Truth, New Holly and West Seattle Library branches (分馆). Teen volunteers and kids read together, learn math and play educational games with support from librarians.

    If you are a high school student who enjoys math, reading and helping kids succeed in school, please consider volunteering as a Learning Buddy. You will get service learning experience and earn(获得) community service hours for school.

Learning Buddies teaches kids once a week. Volunteer chances are offered at the following Library branches, October through December and March through May.

    Beacon Hill Branch: Tuesday, 4:15 p.m. to 5:45 p.m.

    Columbia Branch: Thursday, 4:15p.m. to 5:45 p.m

    Douglass-Truth Branch: Tuesday, 4:15 p.m.to 5:45 p.m.

    New-Holly Branch: Tuesday, 4:15 p.m. to 5:45 p.m.

    West Seattle Branch: Tuesday, 4 p.m. to 5:30 p.m.

    Become a Learning Buddy

    High school students must be at least 14 years old and live close to a Library branch that offers the Learning Buddies program.

    You can ask for a volunteer application (申请书) and attend an interview at one of the following Library branches at least one month before the fall or spring Learning Buddies series.

    Beacon Hill Branch: call the Teen Services Librarian at 206-684-4711.

    Columbia Branch: call the Teen Services Librarian at 206-386- 1908.

    Douglass-Truth Branch: call Services Librarian at 206-684-4704.

    New-Holly Branch: call the Supervising Librarian at 206-386- 1905.

    West Seattle Branch: call the Teen Services Librarian at 206-684-7444.

On one side of the room sits the cutest life-size stuffed animal(填充玩具) you've ever seen. On the other side rests a real dog—the same size, shape and even the same name as the stuffed version. You get to sit next to both of these furry friends and pet their fur. Guess which one will make your brain light up?

If you guessed the real dog, you're right. Stuffed animals, as cute and lovely as they may be, just don't effectively activate our frontal cortex(额叶皮层), the part of the brain overseeing how we think and feel, according to a new study published in the journal PLOSONE. The study found an even stronger rise in brain activity when the person petted the fur of a real dog versus a stuffed animal.

"We chose to research the frontal cortex because this brain area is involved in several executive(执行) functions, such as attention, working memory, and problem-solving. But it is also involved in social and emotional processes,"said study lead author Rahel Marti, a doctoral student in the division of clinical psychology at the University of Basel in Switzerland.

Why is this finding important? It provides additional evidence that live human-animal interaction therapy(疗法) may promote cognitive and emotional activity in the brain. Marti said,"If patients with deficits in motivation, attention, and socioemotional functioning show higher emotional involvement in activities connected to a real dog, then such activities could increase the chance of learning and of achieving treatment aims."

"This is an interesting, seriously conducted study that provides new insight into associations between human-animal interaction and regional prefrontal brain activity in healthy adults. We found that brain activity increased when the contact with a real dog or a stuffed animal became closer. This confirms previous studies relating closer contact with animals to increased brain activity,"Marti said.

Getting rid of old tyres (轮胎) has long been a problem. Most are thrown into landfills or piled up in storage. Energy recovery is another common method. This involves burning tyres to generate electricity or heat for industries, but that produces planet warming pollution; or we use them to

repair roads, but chemicals from them might pollute the ground.

Some firms, therefore, have begun exploring an alternative. One such firm is Wastefront, which owns a big tyre-recycling plant in north-east England. In a couple of years, it will be able to turn 8 million old tyres into new products, including a black liquid called TDO (轮胎衍生油).

The process works by deconstructing a tyre into steel, rubber, and carbon black. After tearing down the steel, the remaining material is exposed to high temperatures in the absence of air to make the rubber change into a mix of hydrocarbon gases, and then they're removed. What is left behind is pure carbon black. Once the removed gases cool down, a part of them liquefies(液化) into TDO. The remaining gases are to be burned to fuel the process. This creates a closed-cycle system that prevents emissions. 

The carbon black can be reused to make new tyres. That is of interest to tyre-makers because it helps efforts to become carbon neutral—achieving a balance between the amounts of carbon dioxide produced and the carbon dioxide removed from the atmosphere. Producing new carbon black requires burning heavy oil or coal, which lets off plenty of greenhouse gases.

The recovered TDO is well-suited for making diesel ( 柴油). While not completely carbon-neutral, it does produce an 80-90% reduction in emissions of carbon dioxide, compared with the conventional fuel. The future market for such cleaner fuels will remain large, even though electric vehicles are on the rise. Fossil-fueled vehicles will exist for decades, particularly the big burners of diesel—trucks, which are harder to electrify. The fuel is also needed by trains and ships. So, anything that helps clean up overall emissions is useful—especially if it also eases a mountainous waste problem.