Most of us have quite good memories, but our memories are limited. For example, we cannot remember everyone we have ever met or what we did on every single day of our lives. However, there are some people who do have prodigious memories. These people have a rare condition known as savant syndrome（学者症候群）. Savants suffer from a developmental disorder, but they also exhibit great talents that contrast（显出差异）sharply with their physical and mental disabilities.

    Kim Peek (1951-2009) was a savant who lived in Salt Lake City, Utah, in the United States. He was born with damage to parts of his brain, but it seemed that other parts of his brain, particularly those relating to memory, became over-developed.

    Peek's unique abilities appeared at a very early age. When he was just 20 months old, he could already remember every book that was read to him. Peek could read two pages of a book at the same time-one page with the right eye and one with the left-in less than 10 seconds and remember everything he read. By the time he died, Peek had memorized more than 9,000 books. He could remember all the names and numbers in a variety of telephone books. He could remember thousands of facts about history, literature, geography and sports.

    Dr. David Treffert, an expert on savant syndrome, once described Peek as “a living Google” because of his astonishing ability to memorize and connect facts. However, at the same time, Peek was unable to carry out simple tasks, such as brushing his hair or getting dressed, and he needed others to help him. In 1989, the movie Rain Man won the Oscar for best Picture. The main character in the movie, played by Dustin Hoffman, was based on Kim Peek's life. He started to appear on television, where he would amaze audiences by correctly answering difficult questions on different topics. Peek-became world famous, and he and his father began touring widely to talk about overcoming disabilities. He inspired a great many people with his words. “Recognizing and respecting differences in others, and treating everyone in the way you want them to treat you, will make our world a better place for everyone. Everyone is different.”

    As the weather gets colder, we start wearing jackets, and most of us stop thinking about the sun. But the sun's rays can be just as harmful when it's cold and cloudy outside. "Any exposed area of your body can still get sunburned," Dr. Apple Bodemer, an associate professor at the University of Wisconsin-Madison, told Live Science.

    Whether you spend a day on the slopes, skating on a pond or clearing snow out of your driveway, your face is still getting exposed to the sun's radiation in the form of ultraviolet (紫外线) (UV) light, which can go deep into your skin cells causing DNA damage, according to Bodemer.

    The sun's long ultraviolet A (UVA) waves can cause earlier aging, sunspots and wrinkles, while its short ultraviolet B (UVB) rays are known for causing skin reddening and burns.

    Skin damage caused by UV exposure increases over time. More exposure to radiation contributes to more severe damage, even skin cancer. In addition, snow and ice can also make sun damage worse. They reflect up to 80 percent of UV rays reaching the ground. That means you get hit from both the sky and the ground. And skiers and snowboarders increase their risk of getting sunburned even more because UV exposure increases at higher altitudes.

    "Generally, the biggest factor for sun-sensitivity is how pale your skin is," he said. "But, the reality is that even the darkest individual can get sun damage."

    Luckily, the solution for protecting your skin is simple: Wear sunscreen every day. Rigel recommended using sunscreen with a sun protection factor (SPF) of at least 30, and going higher at high altitudes. As a rule of thumb, SPF 30 will block 97 percent of UVB rays, SPF 50 blocking 98 percent, and SPF 100 blocking 99 percent. Whatever kind of sunscreen you use, it's important to apply SPF about once every 2 hours.

    Rigel also suggested sunscreens with "broad spectrum (光谱)"—to protect against both UVB and UVA rays—as well as sunscreens that are water resistant for up to 80 minutes. That way, you can go about your day without it wearing off too quickly.

    Adrian Lamo, a Colombian-American threat analyst and former hacker, died in Sedgwick County, Kansas on Friday, at the age of 37. He was best known for passing on information that led to the arrest of Chelsea Manning.

    Lamo first gained media attention in the early 2000s for breaking into several high-profile computer networks, including those of The New York Times, Yahoo, and Microsoft, ending in his 2003 arrest when he eventually turned himself in.

    However, Lamo gained worldwide ill reputation in 2010 for disclosing to the FBI that the U.S. soldier, Chelsea Manning had leaked confidential information to Wikileaks. Manning had reached out to Lamo via a messaging app and told him that he had gained access to hundreds of thousands of classified documents and had leaked to Wikileaks a video of U.S. military forces in a helicopter machine madly gunning down journalists and Iraqi civilians. But, Lamo chose to report him and informed the U.S. military of the leak.

    Held responsible for the biggest leak of classified data in U.S. history, Manning was declared guilty by court martial and was sentenced to 35 years in prison, but was granted mercy by former President Barack Obama, who said his prison term was "disproportionate".

    Looking back on his decision to give up Manning, Lamo told US News and World Report in 2017 that it was "not his most honorable moment".

    However, he added that he had learned a lot from the experience, including that "you can't really know a person or their motives unless you've sat where they sat and seen the situation through their eyes, no matter how much you believe you do".

    While elephants born without tusks (长牙)are not unheard of，they normally form just 2 to 6 percent of the population. However, that is not the case at Mozambique's Gorongosa National Park, where an astonishing 33 percent of female elephants born after the country's civil war ended in 1992 are tuskless. While that may appear to be just a coincidence, Joyce Poole, an elephant behavior expert, has another theory. The researcher thinks we may be witnessing unnatural evolution of the species due to the constant hunting of elephants for valuable ivory.

    Poole says before the country's 15-year-long civil war, the 100,000-acre park was home to over 4,000 elephants. However, by the time the conflict ended in 1992, about 90 percent of them had been killed for ivory to help finance weapons (武器)and meat to feed the soldiers. Of the less than 200 survivors, over 50 percent of adult females had no tusks. Therefore, it is not surprising that the park's tuskless elephant population has grown greatly.

    This is not the first time researchers have observed a great change in the population of elephants. At Zambia's South Luangwa National Park and Lupande Game Management Area， areas which were heavily hunted in the 1970s and 1980s, 35% of elephants 25 years or older and 13% of those younger than 25 are now without tusks. A 2008 study published found that the number of tuskless females at the Ruaha National Park in Tanzania went from 10.5 percent in 1969 to almost 40 percent in 1989, largely due to illegal hunting for ivory.

    The recent ban on ivory in both the US and China should help get rid of, or at least reduce, elephant hunting. However, scientists are not sure how long it will take for elephants with a higher rate of tuskless females, to change the trend.

    Google previously announced successful tests of machine learning systems designed to assist doctors. In one case, Google reported AI had examined eye diseases with equal accuracy to doctors. Other tests showed that machine learning can be used to study large amounts of patient data to predict future medical events.

    Now the company has published two new studies showing a high level of success in identifying metastatic breast cancer. Metastatic means that cancer has spread from its main area to other parts of the body. Metastatic breast cancer is one of the deadliest, causing about 90 percent of all breast cancer deaths worldwide.

    In metastatic breast cancer patients, the cancer often travels to nearby lymph nodes（淋巴结）. Usually doctors examine lymph node tissue under a microscope to see whether cncer is present Google notes that previous studies have shown that up to one-fourth of metastatic lymph node classifications end up being changed after a second examination. In addition, studies show that small metastatic material can be missed up to 67 percent of the time when examinations happen under extreme time restrictions.

    Google says it created a mathematical algorithm(算法).The algorithm, called Lymph Node Assistant, is trained to find characteristics of tissue affected by metastatic cancer. When the system examined tissue images (图像), it was able to differentiate between metastatic cancer and non-cancer 99 percent of the time. In addition, the Lymph Node

    Assistant is highly effective at finding the positions of the cancers. Some of these positions would be too small for doctors themselves to identify. The research also showed that the algorithm method can reduce the usual time needed to examine the disease by about 50 percent.

    But Google makes clear the Al-based system is not meant to replace the work of medical professionals. Instead, it is designed to reduce the number of false identifications and help doctors work faster and more effectively.

    US inventor Thomas Alva Edison once said: "Genius is one percent inspiration and 99 percent perspiration." He was not exaggerating. Perspiration, indeed, plays a very important role in Chinese scientist Tu Youyou's success.

    Tu was given the Nobel Prize in Physio logy or Medicine in 2015 for discovering a new drug for malaria, a deadly disease caused by the bite of some types of mosquito. She is the first Chinese citizen to win a Nobel Prize in science. "It is the pride of the whole Chinese science community, which will inspire more Chinese scientists," China Daily noted.

    Malaria is a disease that infects around 200 million people and k ills about half a million people each year, according to the Economist. Tu's discovery has saved millions of lives, especially in the developing world. According to the World Health Organization, by 2013 malaria deaths had fallen by 47 percent compared with 2000.

    But the road to this achievement was a tough one to travel. In the late 1960s, during the "cultural revolution" (1966-1976), Tu joined a government project on which she began research on a new malaria drug.

    In the beginning, Tu read a lot of old folk remedies(药方), searched texts that w ere hundreds or thousands of years old and traveled to remote places.

    Over several months, Tu and her team collected over 600 plants and created a list of almost 380 possible remedies.

    "This w as the most challenging stage of the project," Tu told The Beijing News. "It was a very labor-demanding and dull job, in particular when you faced one failure after another."

    But the hard work and the dullness failed to break the team's spirit. In the following months, she and her team tested the remedies on malaria- infected mice and they found that an extract(提取物)from the plant qinghao seemed to work w ell.

    Not that the work was easier after that. The fact that the extract didn't always work against malaria discouraged some of her teammates. But Tu was ambitious to make a contribution to the world and so she encouraged her teammates to keep going. They decided to start again from the beginning.

    In 1971, they were rewarded for their efforts. After nearly 200 failures, Tu finally made an extract that was 100 percent effective  against malaria parasites.The extract was called "Artemisin in"(青蒿素).

    Thanks to decades of hard work, Tu and her team had "provided humankind with powerful new means to combat these diseases that affect hundreds of millions of people every year," said the Nobel Prize Committee. "It has greatly improved human health and reduced suffering."