【推荐1】Mathew White, an environmental psychologist, is on a mission to give Mother Nature the respect he thinks she deserves when it comes to human health. For decades, scientists and health-care professionals have recognized that exposure to green spaces, such as public parks or forests, is linked with lower risks of all sorts of illnesses common in the world. Experimental work has demonstrated various physiological responses that occur when people spend time in natural environments: blood pressure drops, heart rate decreases, immune function improves, and the nervous system directs the body to rest and digest.

As humans increasingly populate urbanized areas, they are spending less and less time in natural environments. But before doctors can start advising their patients to head to the nearest park, there is an important outstanding question, says White: How much time in nature do you need to generate these apparent benefits? Most of the research that has linked health outcomes with exposure to the natural world didn’t use frequency or duration of park visits, but rather the amount of green space within a certain distance of a person’s home, White says. But “it’s not so much where you live; it’s whether you use it or not.”

So he collected data to estimate what dose（剂量） of nature was needed to show benefits to a person’s health. White’s group found the answer he was after: Spending at least two hours in nature per week was strongly correlated with self-reports of being in good health or having high wellbeing. “I was very surprised, to be honest,” says White, who had been expecting a much longer time. “We had no idea that such a clear threshold of time per week would emerge from the data.”

He was further surprised to learn that it didn’t seem to matter how many trips to a park people took, so long as they got in their two hours per week. It could be a long visit one day, a couple of hour-long trips, three visits of 40 minutes, or four half-hour excursions. He and his colleagues speculate that, if nature’s apparent health benefits are a result of being able to de-stress, then whatever pattern of green space exposure fits one’s schedule is probably the best way to achieve that goal.

Health-care recommendations for people to spend time in nature are probably years away, but the movement has begun. Several organizations around the world are working to promote awareness of nature’s contribution to health. Some researchers have used the term “a dose of nature” to evaluate the amount of exposure needed to gain benefits. “That was kind of the deliberate medicalization of the language around nature and health,” says White.

【推荐2】Antarctica(南极洲)’s melting ice, which has caused global sea levels to rise by at least 13.8 millimeters over the past 40 years, was thought to primarily come from the unstable West Antarctic Ice Sheet(WAIS). Now, scientists have found that the East Antarctic Ice Sheet (EAIS)—considered largely unaffected by climate change—may also be melting at an unexpectedly rapid speed.

The WAIS, whose base is below sea level, has long been considered the most likely to break down. Besides gravity, a deep current of warm water slips beneath the sheet, melting it from below until it becomes a floating shelf at risk of breaking away. In contrast, extreme cold and a base mostly above sea level are thought to keep the EAIS relatively safe from warm waters.

But as greenhouse gases warm much of the planet, driving stronger polar winds, some scientists think warm water carried by a circular current will start to invade East Antarctica’s once unassailable ice. A cooperation of more than 60 scientists last year, published in Nature, estimated that the EAIS actually added about 5 billion tons of ice each year from 1992 to 2017.

Eric Rignot of the University of California, Irvine, and colleagues combined 40 years of satellite imagery and climate modeling and found that overall Antarctica now sends six times more ice into the sea each year than it did in 1979, with the majority coming from West Antarctica. But East Antarctica was responsible for more than 30% of Antarctica’s contribution to the 13.8-millimeter sea level rise over the past 40 years. “The more we look at this system the more we realize this is fragile,” Rignot says. “Once these glaciers become unstable there is no red button to press to stop it.”

Rignot hopes the study brings greater attention to a part of Antarctica that has traditionally been understudied. Helen Fricker, a glaciologist (冰川学家) in California, agrees. “We need to monitor the entire Antarctica and we just can’t do that without international cooperation.”

【推荐3】According to a new study from Cornell University, about one-fifth of the global population, of 2 billion people worldwide, will be forced to resettle or go deeper inland by 2100 due to the continuous rise in sea level.

The study, published in the journal Land Use Policy, showed that the growing global population could make the matter worse. The researchers expected that there are about 1.4 billon “climate change refugees(难民)” in the world by 2060 and by 2100 the number of the displaced people due to the rising sea level could reach up to two billion.

“We’re going to have more people on less land and sooner than we think,” said lead author Charles Geisler, professor at Cornell. “The future rise in global average sea level probably won’t be gradual. Yet few policy makers are observing the significant barriers that coastal climate refugees, like other refugees, will run into when they move to higher ground.”

For the study, the researchers reviewed(回顾) potential problems that climate change refugees may face if they go deeper inland. The researchers identified these land difficulties with relocation using three organizing groups. Including depletion(损耗) zones, win-lose zones and no-trespass(不得擅自进入) zones. By doing so, the researchers were able to provide primary estimates of their toll(损失) on inland resettlement space. The researchers found that some inland regions were unlikely to support new waves of climate change refugees due to the remains of war, road developments and rare natural resources.

Apart from the rising sea level, increasing storm weather and the booming global population are also having a huge influence on the number of climate change refugees. Storm can push seawater further inland. The increasing global population requires more land even as the ocean swallows up rich costal zones and river deltas(三角洲). These force people to search for new places to move to higher ground.

【推荐1】Although small business training and credit programs have become more common throughout the world, little attention has been paid to the need of young people, and even less to the children living on the street or in difficult condition.

Over the past nine years, Street Kids International (S.K.I.) has been working with partner organizations in Africa, Latin America and India to support the economic lives of street children and develop opportunities for street children to earn income.

The S.K.I. Bicycle Courier Service first started in the Sudan. Street children who took part in it were given bicycles, which they used to deliver parcels and messages. A similar program was taken up in Bangalore, India. The Shoe Shine Collective was a program with the Y.W.C.A. in the Dominican Republic. The children in this project were lent money to buy shoe shine boxes. They were also given a safe place to store their equipment, and facilities for individual savings plans. The Youth Skills Enterprise Initiative in Zambia is a program with the Red Cross Society and the Y.W.C.A. Street youths are supported to start their own small business through business training, life skills training and access to credit.

During the program, The S.K.I. and partner organizations have drawn lessons from the past: First of all, being a businessman is not for everyone, nor for every street child. And it is important for all loans to be linked to training programs that include the development of basic business and life skills. Secondly, small loans are provided firstly for buying fixed assets such as bicycles, shoe shine kits and basic building materials for a market stall. As the children gain experience, they can be given more loan amounts. And all S.K.L. programs have charged interest on the loans. Generally the rates have been lower than bank rates. Most importantly, it is believed that credit must be given with other types of support that help the young develop key life skills as well as productive businesses.

【推荐2】Is there a way to turn back the aging process in people? For centuries, people have been looking for a “fountain of youth.” The idea is that if you find a magical fountain, and drink its water, you will not age.

Researchers in New York did not find an actual fountain of youth, but they may have found a way to turn back the aging process. It appears that the answer may be called the hypothalamus, which is part of your brain. It controls important body activities, including growth, the way we process food and so on. Researchers found that hypothalamus neural stem cells (干细胞) also influence how fast aging takes place.

Dongsheng Cai was the leading researcher in a study on aging in mice. He and his team reported their findings. “when the hypothalamus starts aging, particularly the loss of hypothalamus stem cells, so does the body.” he said.

Using this information, the researchers began trying to activate (激活) the hypothalamus in laboratory mice. The results show that the treatment slowed aging in the animals. “When we injected the hypothalamus stem cells to the middle-aged mice, the mice aged slowly and they could also live longer.”

But these results were just from studying mice in a laboratory. If the mice can live longer, does that mean people could have longer lives? The next step is to see if the anti-aging effects also work in human beings. If so, they say the findings could lead to new ways to help doctors identify and treat age-related health problems.

【推荐3】In a major medical breakthrough, Tel Aviv University researchers have “printed” the world's first 3D vascularized (有血管的）engineered heart using a patient’s own cells and biological materials. Their findings were published on April IS in a study in Advanced Science.

“This is the first time anyone anywhere has successfully engineered and printed an entire heart,” says Prof. Tal Dvir of Department of Materials Science and Engineering, who led the research for the study. “This heart is made from human cells and patient-specific biological materials. In our process, these materials serve as the bioinks, something made of sugars and proteins that can be used for 3D printing of complex tissue models，” Prof, Dvir says. “People managed to 3D print the structure of a heart in the past, but not with cells or with blood vessels (血管).Our results demonstrate the potential of our approach for engineering personalized tissue and organ replacement in the future.”

According to Prof. Dvir，the use of “ native ” patient-specific materials is important to successfully engineering tissues and organs.

The researchers are now planning on culturing the printed hearts in the lab and “ teaching them to behave” like hearts, Prof. Dvir says. They then plan to transplant the 3D-printed heart in animal models.

“We need to develop the printed heart further，” he concludes. “The cells need to form a pumping ability ； they can currently contract (收缩），but we need them to work together. Our hope is that we will succeed and prove our method’s efficacy (功效)and usefulness. “Maybe, in ten years, there will be organ printers in the finest hospitals around the world，and these procedures will be conducted routinely. ”