Last year, around Labor Day, I read a “Happy Ad” in our local newspaper. There was a lady in a local nursing home for the aged, who was celebrating her 90th birthday and her family wanted everyone to know about it. It said that if you wanted to drop her a line, here was her address. So I did. I found a birthday card and dropped her a short note, wishing her a happy birthday.

    A week or so later, someone knocked at my front door. I opened the door and found a middle-aged man standing on my doorstep. He introduced himself as the son of this woman to whom I had sent the card. He explained that he just wanted to drop by in person and thank me for sending such a nice card to his mom. Apparently, like many older folks, she did not receive much mail and was quite excited to receive mine. I just didn't know what to say. I told him it was my pleasure and that I hoped his mom had enjoyed her birthday.

    That year, I did not send out any Christmas cards, except to this lovely old lady in the nursing home. I just told her that I was thinking about her and hoped that she had a nice holiday. I sent her a holiday card and also a couple of notes in between. I just thought she might like to have someone write to her, to get some mails.

    She passed away a couple of months ago. I never met this lady, but I did keep her and her family in my thoughts. I dropped them a line of sympathy. I hope that my few little notes were enough to brighten a couple of her days here on earth.

    Believe it or not, the size of the human brain has become smaller over the past 20,000 years. Scientists argue over whether this means we are becoming more or less intelligent as a species.

    “I'd call that a major downsizing in an evolutionary eye blink (眨眼),” John Hawks told Discover magazine.

    Why is the brain becoming smaller?

    There are different theories to explain it. One is that tens of thousands of years ago, before the decline began, to survive in cold and dangerous conditions, humans needed a stronger and larger body and therefore, a larger head. Also they had to chew the tough meat of rabbits, foxes and horses. As conditions improved, the brain stopped growing, according to supporters of this theory.

    Another theory comes from a recent study by David Geary and Drew Bailey. They found that brain size decreased as population density(密度) increased.

    “As complex societies appeared, the brain became smaller because people did not have to be as smart to stay alive.” Geary told AFP.

    But smaller brain size does not necessarily mean that modern humans are less smart than their ancestors. “Modern humans simply developed different, more complex forms of intelligence,” said Brian Hare.

    Hare's studies focus on two types of great apes: chimpanzees and bonobos. Both are much like humans, but are physically quite different from one another. The bonobo has a smaller brain than the chimpanzee, and is also much less aggressive and more tolerant.

    “When it comes to working out a problem,” Hare said, “chimpanzees are much less likely to accomplish it if it involves working together. Not so with bonobos.”

The smaller brain in modern humans may be evidence that we can cooperate,” Hare told the US National Public Radio.

    Frequently, we speak about people being “color-blind” but very few of us are. Even those who describe themselves as color-blind are normally just color lack. A strongly, color-blind person will still be able to tell 20 different colors, compared to the 100 or so that normal-sighted people see.

    Pingelap, a tiny island in the Pacific, is a beautiful spot but one that has a genetic trouble. It is known as Color-blind Island because so many people who live on this remote island can only see black and white.

    Not being able to see colors is bad enough. But one islander, Herrol, who's a fisherman, also struggles in full sunlight because all he sees is a painful burnt-out image. “I find it difficult to go outside in the sun,” he says, “because when it's sunny I cannot see to do my work.”

    But if being truly color-blind is rare, why is it that around 10% of the population of Pingelap live in a totally black and white world?

    Well, we know that in 1780 the population of Pingelap was all but wiped out by a tsunami (海啸). As few as 20 people survived, one of whom was the king. It's believed he had a genetic fault that causes colour-blindness and he passed this fault on to his many generations.

    There is one advantage. Herrol can see well, really well, in the dark. So when it gets dark, Herrol and his friends get in their boats and hunt flying fish. They hang up flaming torches and the fish are attracted to the flames. “This type of fishing is fun,” Herrol says, “especially if we catch plenty. So even though it's hard work we enjoy it.”

    It happens from time to time: you feel terrible when you take your first bite of a certain food, but after eating more, you find yourself enjoying it. This is what is called an acquired taste. But why do our tastes change?

    The answer, according to a recent study presented at an American Chemical Society meeting in Boston, lies in proteins in our saliva (唾液).

    Most of us tend to think saliva, almost entirely made up of water, is “only a mouth lubricant (润滑剂) helping us to swallow food,” the New York Times said. However, it also contains many proteins, which can help break food down, protect our teeth and help in tasting food.

    To explain how these proteins affect taste, a team of scientists from Purdue University in the US invited 64 volunteers to drink a bitter-tasting chocolate milk three times a day for six weeks and rated their tastes at the same time.

    According to the research, the participants found a strong bitterness on the first day, but the unpleasant flavor came to decrease as time went on and finally disappeared.

    That is not all that was changing. A noticeable increase in the levels of proline-rich (富含脯氨酸的) proteins was found in the saliva samples of the test subjects in the research period. These proteins serve to reduce the bitterness we taste and improve our adaptation to this flavor.

    “We think the body adapts to reduce the negative feeling of these bitter compounds,” said Cordelia Running, a food scientist at Purdue University. “Saliva changes flavor, which in turn changes eating choices.”

    This change in taste not only makes the food tastier, but also helps people keep an appetite for healthy food whose flavor might otherwise keep them away.

    One day, these proteins may even be extracted (提炼) and used as a separate food additive that could help people stick to healthy food whose flavor they continue to dislike, researchers told Science Alert. And according to Running, even it doesn't happen, the idea that “maybe some little piece of your body is actually trying to help you” could really benefit some people. Let's wait and see.

Do you continue to be healthy in social isolation? NASA is looking for people to spend 8 months locked in a Russian lab for a new experiment.

When humans go to the moon and travel to Mars, they will need to be prepared for long-term space travel and even longer stays on these far-off destinations. Currently, NASA's Artemis program aims to land humans on the moon for the first time since NASA's Apollo 17 mission landed in 1972.

While the moon is the main goal of NASA's Artemis program, the agency's larger goal is to send people to Mars. But long-term space travel and habitation won't be easy. Such missions will present both physical and mental challenges as astronauts work to not only survive, but perform important scientific research in uniquely difficult environments.

In the upcoming NASA-Russia experiment, a group of people will live in a closed facility at Russia's Institute for Biomedical Problems, which is in Moscow. This habitat facility was used in2011 for notable series of Russian mock (模拟的) Mars missions known as Mars 500. During these missions, groups of people spent 520 and 105 days on two separate missions in the facility.

The facility, according to the statement, will have "environmental factors similar to those astronauts are expected to experience on future missions to Mars". The group of people will spend 8 months living together in isolation and working on scientific research.

By living and working in this Mars-like environment, participants in this study will help NASA researchers better understand the psychological and physiological (心理和生理的) effects of isolation. These missions help researchers not only perform relevant science experiments but also see how people might get on under strange conditions for long periods of time.

So, if you're finding that living in social isolation works for you, you might be particularly well-suited for living in a Mars-like environment and this could be for you. But first, you have to qualify. NASA is looking for "highly motivated" Americans between the ages of 30-55, who must speak both Russian and English fluently and have a Master of Science, Doctor of Philosophy, Doctor of Medicine, or military officer training. Applicants with other related experience may also be considered. Those who are chosen to be a part of this group will be paid for their work.

Painting is an ancient medium and even with the introduction of photography, film and digital technology, it still has remained a persistent mode of expression. So many paintings have come into being over the years but only a small percentage of them could be described as "timeless classics". The following are some of the most famous paintings of all time. 

Leonardo Da Vinci, Mona Lisa, 1503—1519

Painted between 1503 and 1519, Leonardo da Vinci's attractive portrait has been a subject of controversy since the day it was made, due to two questions: Who's the subject and why is she smiling? A number of theories for the former have been provided over the years: That she's the wife of the Florentine merchant Francesco di Bartolomeo del Giocondo and that she's Leonardo's mother, Caterina. As for that famous smile, its quality has driven people crazy for hundreds of years. 

James Abbott McNeill Whistler. Arrangement in Grey and Black No. 1. 1871

Whistler's Mother, or Arrangement in Grey and Black No. 1, as it's actually titled, speaks to the artist's ambition to pursue art for art's sake. James Abbott McNeill Whistler painted the work in his London studio in 1871. Whistler's mother Anna is pictured as one of several elements locked into an arrangement of right angles. Her severe expression fits in with the rigidity of the composition, and it's somewhat ironic to note that despite Whistler's formalist intentions, the painting became a symbol of motherhood. 

Jan van Eyck, The Arnolfini Portrait, 1434

As one of the most significant works produced during the Northern Renaissance, this composition is believed to be one of the first paintings finished in oils. It portrays an Italian merchant and a woman who may or may not be his bride. In 1934. the celebrated art historian Erwin Panofsky proposed that the painting is actually a wedding contract. What can be reliably said is that the piece used orthogonal perspective to create a sense of space. It feels like a painting you could step into.