科普环保类 知识点题库

    It's a popular belief that a fish's memory lasts for only seven seconds. It may seem sad to think that they don't remember what they've eaten or where they've been, and they don't recognize you or any of their friends — every moment in their life would be like seeing the world for the first time.

    But don't be so quick to feel sorry for them. A new study has found that fish have a much better memory than we used to think. In fact, certain species of fish can even remember events from as long as 12 days ago.

    In the study, researchers from MacEwan University in Canada trained a kind of fish called African cichlids to go to a certain area of their tank to get food. They then waited for 12 days before putting them back in the tank again.

    Researchers used computer software to monitor the fish's movements. They found that after such a long break the fish still went to the same place where they first got food. This suggested that they could remember their past experiences.

    In fact, scientists had been thinking for a long time that African cichlids might have a good memory. An earlier study showed that they behaved aggressively（挑衅地） in front of certain fish, perhaps because they remembered their past “fights”. But until the latest findings, there was no clear evidence.

    Just as a good memory can make our lives easier, it also plays an important part when a fish is trying to survive in the wild.

    “If fish are able to remember that a certain area contains safe food, they will be able to go back to that area without putting their lives at risks,” lead researcher Trevor Hamilton told Live Science.

    For a long time, fish were placed far below chimpanzees, dolphins and mice on the list of smart animals. But this study has given scientists a new understanding of their intelligence.

    According to a team of researchers, an animal's ability to perceive(感知) time is linked to their pace of life.

    “Our results lend support to the importance of time perception in animals where the ability to perceive time in a very short time may be the difference between life and death for fast moving creatures.” commented lead author Kevin Healy from Trinity College Dublin.

    The study was done with a variety of animals using phenomenon based on the maximum speed of flashes of light an individual can see before the light source is seen as constant. Dogs, for example, have eyes with a refresh rate higher than humans.

    One example of this phenomenon at work, the authors say, is the housefly and its ability to avoid being hit. The research showed flies “observe motion in a shorter time than our own eyes can achieve,” which allows them to avoid being hit.

    Professor Graeme Ruxton of the University of St Andrews in Scotland, who worked jointly on the research project, said in a statement, “Having eyes that send updates to the brain at much higher frequencies than our eyes do is of no Value if the brain cannot process that information equally quickly. Thus, this work highlights the impressive abilities of even the smallest animal brains. Flies might now be deep thinkers, but they can make good decisions very quickly.”

    In comparison, the tiger beetle (虎甲虫) runs faster than its eyes can keep up, basically becoming blind, which requires it to stop periodically to re-evaluate its prey's(猎物) position.

    Our results suggest that time perception offers an as yet unstudied dimension along which animals can specialize and there is considerable range to study this system in more detail.

Senses That Work Together

    When we think about how our senses work, we usually imagine them operating separately: you sniff a flower, and the smell is delivered uninterrupted from nose to brain. However, it's more complex than that. Most evidence for cross-modal perception (知觉) comes from studies into sound and vision (视觉). But research that shows other senses crossing over is coming out all the time, and it seems that even sound and smell sometimes form an unlikely pairing.

    When New York researchers, Daniel Wesson and Donald Wilson, tried to find out the truth about a “mysterious” area of the brain called the olfactory tubercle (嗅结节)，they had to deal with this fact. Originally, they only intended to measure how olfactory tubercle cells in mice responded to smell. But during testing, Wesson noticed that every time he put his coffee cup down with a clunk (哐啷声)，the mouse cells jumped in activity. In fact, the olfactory tubercle is well-placed to receive both smell and sound information from the outside world. Later they found that among separate cells, most responded to a smell but a significant number were also active when a sound was made. Some cells even behaved differently when smell and sound were presented together, by increasing or decreasing their activity.

    Of course, mice aren't people, so research team has been carrying out further experiments. They pulled together a group of people and gave them various drinks to smell. Participants were asked to sniff the drinks, and then match them to appropriate musical instruments and produce the notes at different levels. The results were interesting: piano was regularly paired with fruity fragrances; strong smells sounded like the instruments that are made of metal.

    Further research found that listening to different sounds can change your perceptions. Studying taste this time, the team ordered some special toffee (太妃糖)and put together “soundscapes” corresponding to bitterness and sweetness. Participants tasted similar pieces of toffee while listening to each soundscape, and found the toffee more bitter or sweeter, depending on which soundtrack they were listening to.

    Studies like this are helping scientists correctly describe our understanding of the senses, and how the brain combines them with its advantage. The consequences are worth considering. Could we see musicians work together with chefs to produce sound-improved food and drink? Will you be ordering a coffee with a soundtrack to bring out your favorite smell? Come to think of it, that could be one thing you hope coffee shop chains don't get round to.

    For as long as we've known about it, humans have searched for a cure for cancer. Across the world, countless amounts of time and money have been spent on researching a way to stop this terrible disease. But now, it seems like the answer could have been inside our own bodies the whole time.

    Recently, the Food and Drug Administration (FDA) in the US, a government agency that's responsible for healthcare, approved a new form of gene therapy (疗法) that could mean the end of a certain type of cancer.

    The therapy allows scientists to "train" the immune (有免疫力的) cells of sick patients to fight leukemia (白血病)—a form of blood cancer that mostly affects young people.

    The exciting new treatment works by removing healthy immune cells from the patient, known as T-cells, which are then changed to be able to "hunt down" cancer cells.

    The cells are then put back into the patient before they begin to get rid of the patient's leukemia over time, similar to how the body fights off other illnesses.

    "This is truly an exciting new day for cancer patients," Louis J. DeGennaro, president of the Leukemia and Lymphoma Society, said in a news release.

    Up until now, a long and painful marrow transplant (骨髓移植) was the only option for many leukemia patients.

    In this procedure, healthy blood cells are taken from a donator and placed into the sick patient, who also has to go through chemotherapy (化疗) to allow their body to adjust to the new cells.

    But with a recovery rate of around 83%—according to a news release published by the FDA—it's hoped that the days of painful trips to the hospital, or even death, are over for leukemia sufferers.

    "We're entering a new frontier in medical innovation (创新) with the ability to reprogram a patient's own cells to attack a deadly cancer," FDA representative Scott Gottlieb said in the release. "New technologies such as gene and cell therapies hold the potential to transform medicine and our ability to treat and even cure many incurable illnesses."

    After photographer Monni Must's daughter Miya died, the sad mother adopted her black dog, Billy Bean. As Billy became increasingly weak, the thought of its dying was just more than Must could handle. So she decided to clone the dog. “I feared everyone was going to forget Miya," she said, "and my other daughters thought I had completely lost my mind."

    Billy's cells were shipped to ViaGen Pets, a Texas company that provides the cloning service. With more than $50,000, Must picked up a new puppy. "The dog has a real soul and is everything my daughter was—fun, social and kind," she said. "I feel that I still have that touchable connection and not just a spiritual connection.”

    Cloning animals is hardly new. But the recent news that singer Barbra Streisand had cloned her dog grabbed international headlines. People for the Ethical Treatment of Animals(PETA) president Ingrid Newkirk issued a statement saying she would love to talk her out of cloning, noting that millions of wonderful dogs are getting old in animal shelters every year or dying in terrifying ways when abandoned.

    Normally, a doctor takes a tissue biopsy(组织活检), a piece of skin and muscle about the size of a pencil eraser, from the dog. The next step is to take an egg cell from a donor dog, remove the egg's nucleus, and insert DNA from the pet to be cloned. When an embryo(胚胎)develops, it is transplanted in the body of a mother dog.

    In the basic cloning procedure, scientists take an entire adult cell and put it into an egg that's been relieved of its own DNA. The resulting embryo is a clone. However, in many animals, only one in 100 cloned embryos ever leads to a live birth. Some embryos die in the IVF dish or in the mothers bodies. Of those that are born, a few suffer from abnormalities and quickly die. Besides, pet cloning doesn't mean copying everything of your beloved pets.

    Microplastics are everywhere in our environment. It's hardly surprising that the tiny fragments have also been found in humans. A new study shows that Americans are consuming as many as 121,000 particles each year.

    Measuring 50 to 500 microns in length, microplastics come from a variety of sources, including large plastics that break down into smaller and smaller pieces. Therefore, much remains unknown about the common existence of these materials within the human body, as well as their impact on human health.

    Hoping to fill in some of these gaps, a research team led by Kieran Cox, a PhD candidate at the University of Victoria, looked at 26 papers assessing the amount of microplastics in commonly consumed food items, among which are seafood, sugars, salts, honey, alcohol and water. The team also evaluated the potential consumption of microplastics through inhalation (吸入)using previously reported data on microplastic concentrations in the air and the Environmental Protection Agency's reported respiration rates. Based on these data, the researchers calculated that our annual consumption of microplastics via food and drink ranges from 39,000 to 52,000 particles. When microplastics taken in through inhalation are taken into account, the range jumps to between 74,000 and 121,000 particles per year.

    The authors of the study found that people who drink exclusively from plastic water bottles absorb an additional 90,000 microplastics each year, compared to 4,000 among those who only consume tap water. "This shows that small decisions, over the course of a year, really matter and have an impact." Cox says. The new study, according to its authors, was the first to investigate "the accumulative human exposure" to microplastics. But in all likelihood, the research tells only a small part of the entire story. Collectively, the food and drink that the researchers analyzed represent 15 percent of Americans' caloric intake. The team could not account for food groups like fruits, vegetables and grains because there simply is not enough data on their microplastic content.

    For those worried about microplastic consumption, cutting down bottled water is a good place to start. But to the heart of the problem, we have to stop producing and using so much plastic.

    A new study suggests household cats can respond to the sound of their own names. No surprise to most cat owners, right? But Japanese scientists said that they've provided the first experimental evidence that cats can distinguish between words we say. So your cats are kind of like dogs, whose communication with people has been studied a lot more, and who've been shown to recognize hundreds of words if they're highly trained.

    Atsuko Saito of Sophia University in Tokyo says there's no evidence cats actually attach meaning to our words, not even their own names. Instead, they've learned that when they hear their names they often get rewards like food or play, or something bad like a trip to the ve（t兽医）. And they hear their names a lot. So the sound of it becomes special, even if they don't really understand it refers to their identity.

    Saito and colleagues describe the results of their research in the journal Scientific Reports. In four experiments with 16 to 34 animals, each cat heard a recording of its owner's voice, or another person's voice, which slowly recited a list of four nouns or other cat's names, followed by the cat's own name. Many cats initially reacted— such as by moving their heads, ears or tails—but gradually lost interest as the words were read. The crucial (关键的) question was whether they'd respond more to their name. Sure enough, on average, these cats perked up when they heard their own name as if delicious food would be offered.

    Kristyn Vitale, who studies cat behavior at Oregon State University in Corvallis but didn't participate in the new work, said the results "make complete sense to me.' 'Vitale, who said she has trained cats to respond to verbal commands, agreed that the new results don't mean that cats actually make sense of their names. It's more like being trained to recognize a sound, she said.

    A facial recognition app, recently developed by scientists, will make it easier to identify（辨认）pandas.

    Wan Yongqing, a Beijing photographer, visits Sichuan Province to take photos of pandas every other year. He has watched them for more than a decade. "My friends say I'm a big panda fan. It is a shame that I find all pandas look the same, with black eyes and white fur. It does not matter as all the pandas are cute to me, "he said.

    Yet, identifying one panda from another does matter to researchers, according to Zhang Zhihe, chief of the Chengdu panda research base.

    "Identifying individual pandas is important for conservation（保护） management and research. For captive（圈养的） pandas, it is important for their daily feeding schedules, family background and data management. For wild pandas, it helps researchers study their population structure and provides scientific support for their protection and management, "he said.

    China has carried out four scientific surveys on wild pandas, and now has a big databank about them. The number of wild pandas in China is mostly known. However, it is still difficult to determine the age, sex, health and other specific information about the population.

    "It's difficult track and watch the structure because wild pandas tend to live alone, deep in the mountains, and their living environment is vast," Zhang added.

    In 2017, the Chengdu base began researching individual panda identification technology by analyzing images. Over the past two years, they have built a databank of more than 120,000 images, over 10,00 video clips, and completed organizing nearly 10,000 images.

    Using the databank, researchers have started a facial recognition app that can accurately recognize captive pandas by analyzing and comparing the unique features of panda faces.

    Panda researchers hope the data and AI technology will help them analyze data for both captive and wild pandas.

    As is thought by many people, air pollution affected only the area around large cities with factories and heavy automobile traffic. At present, we realize that although these are the areas with the worst air pollution, the problem is worldwide. On several occasions over the past decade, a heavy cloud of air pollution has covered the east of the United States and brought health warnings in rural areas away from any major concentration of manufacturing and automobile traffic. In fact, the very climate of the entire earth may be infected by air pollution. Some scientists consider that the increasing concentration of carbon dioxide in the air resulting from the burning of fossil fuels (coal and oil) is creating a "greenhouse effect"—conserving heat reflected from the earth and raising the world's average temperature. If this view is correct and the world's temperature is raised only a few degrees, much of the polar ice cap will melt and cities such as New York, Boston, Miami, and New Orleans will be in water.

    Another view, less widely held, is that increasing particular (颗粒) matter in the atmosphere is blocking sunlight and lowering the earth's temperature—a result that would be equally disastrous. A drop of just a few degrees could create something close to a new ice age, and would make agriculture difficult or impossible in many of our top farming areas. Today we do not know for sure that either of these conditions will happen (though one recent government report drafted by experts in the field concluded that the greenhouse effect is very possible) Perhaps, if we are lucky enough, the two tendencies will offset each other and the world's temperature will stay about the same as it is now. Driven by economic profits, people neglect the damage on our environment caused by the "advanced civilization". Maybe the air pollution is the price the human beings have to pay for their development. But is it really worthwhile?

Changing weather pallerns, stronger storms, longer droughts- these are just a few signs that our climate is changing rapidly.

Recently, lawmakers in New Zealand signed the Zero Carbon Bill, which lays out a path for the country to reduce its carbon emissions to zero by 2050.

Net-zero is the balance between the amount of greenhouse gases a country releases into the atmosphere and how much is removed from the atmosphere.

A reasonable way to achieve net-zero is to divide the goal into two parts. To reduce emissions, countries can gradually adapt their economies to be less carbon dependent. This can be done by developing renewable energy, improving transportation and food production, stopping deforestation and restoring lands, reducing food wastage, and consuming less meat.

Countries can then address remaining emissions with carbon removal, a process that removes greenhouse gases directly from the atmosphere. This can be done by planting more trees and developing technologies that capture and store carbon.

New Zealand's Zero Carbon Bill aims to reduce fossil fuel usage and replace it with renewable energy sources. The government has also focused on promoting electric vehicles, public transportanon, biking, and walking. Additionally, New Zealand is committed to planting 1 billion trees by 2028.

The country wants to include agriculture into its climate solution. The government will tax farmers who do not decrease their carbon emissions by 2022. Currently, agriculture in New Zealand accounts for over half of its greenhouse gas emissions.

Methane is a greenhouse gas produced by the decomposition of organic matter from crops and livestock such as sheep and cattle — known as biogenic (生物的) methane. New Zealand will reduce biogenic emissions by 10% before 2030 and between24% to47% before2050. Here, the country is being denounced for not doing enough as methane is a much stronger greenhouse gas, even though it does not stay in the atmosphere as long as carbon dioxide.

Sixty countries have already committed to net-zero, yet they only make up 11% of global emissions. We need convince our leaders that our planet cannot survive if we don't take action.

What do you do at the end of the day when you're finished with work? How you spend your free time can have a big impact (影响) on your mental health, Hobbies can help you relax and ease pent-up (郁结的) stress caused by all that time in the office or in front of the computer. But, interestingly, how you spend your free time can also impact your work performance.

Researchers at the University of Sheffield's Institute of Work Psychology in the UK found that developing hobbies can develop your confidence about how well you perform your job. But your hobby has to be significantly different from what you do from 9-to-5 work.

To study the connection between work and leisure (休闲) activities, researchers employed 129 people who worked and were active in hobbies like rock climbing, musical theater and singing. They had them complete surveys to see how serious and committed they were to their hobbies and how demanding their jobs were. Then, each month for seven months, participants were asked how many hours they spent on their hobbies and how they rated their ability to perform at work.

Researchers found that if people have hobbies similar to what they do at work and that they do in an intense (强烈的) way, their on the job confidence can suffer. It's likely because their work and leisure time have the same mental and physical demands, so they're always feeling drained.

In contrast, people who have hobbies different from their work are happier and healthier. This is also true of those who choose a similar hobby but only participate in a lighthearted way. Those playful recreations act as a barrier between their professional and personal lives, giving them rest time to "recharge their batteries", the researchers say.

"When we feel like we have the confidence to handle challenges in our jobs. we're more likely to be able to build a sustainable (可持续的) job and remain healthy, productive, happy and employable over our lifetimes. It's important to consider how our leisure activities might play a role in that process," lead researcher Ciara Kelly said in a statement.

Jake Meyers, a graduate student in Northwestern University, has won the Best Sharable Video award in Planet Forward's national Storyfest 2020 competition. The project teaches, celebrates and rewards environmental storytelling by students from across the county.

As a master's student, Meyers works at the intersection of climate adaptation and food security. During the summer of 2019, Meyers worked with the International Livestock Research Institute in Nairobi, Kenya, to investigate climate adaptation solutions to food insecurity in the rapidly urbanizing nation.

Meyers' video, "Can urban farming feed the future?", shares the story of Francis Wachira, a leading advocate for urban facing in Nairobi.

Millions of people are moving from rural to urban areas as large-scale farming, coupled with climate change, forces small-scale farmers to abandon their livelihoods and pursue economic opportunity in urban areas, "Meyers said.

As food security concerns grow for the people of Nairobi, farmers like Francis are transforming urban lots into highly productive green spaces to raise livestock (牲畜), grow vegetables and fight climate change.

"Francis has an incredible urban farming system in Nairobi that features over 600 head of livestock and 150 species of plants, "Meyers said." I wanted to highlight Francis and his innovative approach to urban farming through storytelling with the goal of inspiring change."

"I have become so inspired by many incredible people like Francis Wachira. So many around the world are re-imagining solutions to poverty and climate change, yet their stories remain untold. I hope to continue using storytelling as a means of highlighting different perspectives that can create impact and advocate for transformational change, "Meyers said.

A group of researchers led by Patrick Yu-Wai-Man. an ophthalmologist (眼科医师) at Cambridge University, investigated a new genetic therapy for a form of blindness. Officially, their study was a failure. But it was also a great success, for 29 of the 37 participants reported big improvements in their vision.

The disease in question is Leber Hereditary Optic Neuropathy (LHON)(遗传性视神经病变) .A defective gene leads to sudden and rapid loss of sight, with many sufferers becoming legally blind within a year. It affects between one in 30,000 and one in 50,000 people. Men in their 20s and 30s are particularly at high risk. Since most cases are caused by a mutation (突变) in a single gene, LHON is a good candidate for gene therapy, a form of genetic engineering which aims to replace the defective gene with a working one.

With that in mind. Dr Yu-Wai-Man and his colleagues loaded up a changed virus with a corrected copy of the gene and injected it into their patients' eyes. The researchers controlled the experiment by injecting only one of each patient's eyes--chosen at random--with the virus. The other eye was given a fake injection. Using two eyes in the same patient makes for a perfect control.

The surprise came several months later. The researchers had hoped to see a big improvement in the treated eyes, compared with the untreated ones. They did not, for which the study failed in its primary objective. Instead, in more than three quarters of their patients, they saw significant improvements in both eyes.

On the face of it, that was odd. Only one eye had received the treatment, after all. Follow-up studies in monkeys confirmed what the researchers had suspected. The virus, it seemed, had found a way to travel from one eye to the other, probably via the optic nerve. Tissues and fluids samples from monkeys given the same treatment as the human patients showed viral DNA in both eyes, not just one.

Although it had a happy outcome in this case, the prospect of a gene-therapy virus travelling to places it is not intended to go to might worry regulators. Fortunately, the researchers found no trace of the virus elsewhere in the monkeys' bodies. And. though the study was technically a failure, its practical success means that an effective treatment for LHON may at last be in reach.

The smilodon (剑齿虎) died out probably about ten thousand years ago. Although it is also known as the saber-toothed tiger, it was not a close relative of the modern tiger. The more scientists study the two big cats, the more differences they find.

Tigers are not sociable animals. They generally travel by themselves. The smilodon, on the other hand, probably lived in groups. Tigers run fast while hunting their prey. But the smilodon, with much shorter tails than today's tigers, did not have the balance to run at top speeds. It probably caught its prey by hiding quietly until an animal came near.

Another main difference between today's tiger and the smilodon is the size of the smilodon's teeth. It is known as a saber-toothed cat because of two huge teeth that grew from the top of its jaw(颌). These teeth grew up to nearly 18 cm long and were easily broken and damaged. The smilodon probably used the teeth to bite into soft parts of its prey's body, such as its stomach. A modern tiger's teeth are much smaller, but they are stronger.

The smilodon lived in North and South America from about two million years ago until about ten thousand years ago. Tigers, of course, still exist today and live in eastern and southeastern Asia. No one knows for sure why the smilodon disappeared.

Roboticists at the University of California San Diego have developed an affordable, easy to use system to track the location of flexible surgical robots inside the human body. The system performs as well as current state of the art methods, but the whole system, including the robot, magnets and magnet localization setup, costs around $100. Many current methods also require exposure to radiation, while this system does not.

The system was developed by Tania Morimoto, a professor of mechanical engineering at the Jacobs School of Engineering at UC San Diego, and mechanical engineering Ph. D. student Connor Watson.

"Continuum medical robots work really well in highly constrained (受限的) environments inside the body," Morimoto said. "But it becomes a lot harder to track their location and their shape inside the body." The researchers used existing magnet localization methods, which work very much like GPS, to develop a computer model that predicts the robot's location.

GPS satellites ping (发送) smartphones and based on how long it takes for the signal to arrive, the GPS receiver in the smartphone can determine where the cell phone is. Similarly, researchers know how strong the magnetic field should be around the magnet placed in the robot. They rely on four sensors that are carefully spaced around the area where the robot operates to measure the magnetic field strength. Based on how strong the field is, they are able to determine where the tip of the robot is.

Morimoto and Watson went a step further. They then trained a neural network to learn the difference between what the sensors were reading and what the model said the sensors should be reading. As a result, they improved localization accuracy to track the tip of the robot. "Ideally we are hoping that our localization tools can help improve these kinds of growing robot technologies. We do want to push this research forward so that we can test our system in a clinical setting and eventually translate it into clinical use," Morimoto said.

Experts say that if food were a country, it would rank second behind the US as one of the biggest greenhouse gas polluters. The reason is the rising demand for meat. Animal farming is responsible for 14.5 percent of global methane emissions. While cows are the worst contributors, pigs, sheep, donkeys and other animals play a part as well.

Animal agriculture also causes land to become damaged, water to be polluted and forests to get destroyed. With the world population forecast to rise to 9.8 billion by 2050, things are only looking worse for our already decreasing natural resources. While going vegetarian would help, meat consumption is too deep-rooted in most Western diets to allow for such a sharp, permanent change. That is why experts are advocating substituting some of the beef, chicken, or pork with ordinary insects!

Insects, which grow into adults within a matter of months, if not weeks, are ready for consumption much faster than domestic animals. They also require much less room, use less water and food, and produce far less greenhouse gas than animals.

Of the 1.1 million insect species worldwide, scientists have identified 1,700 as eatable. Among them are ants, grasshoppers, grubs, and earthworms. Just like animals, each insect has a different taste. Tree worms taste just like pork, and grubs are similar to smoked meat.

While eating insects might be a new concept for Western people, over 2 billion people worldwide consume insects as a regular part of their diet. Besides being delicious, insects are high in protein, have very few calories, and are free of the saturated fat found in animal meat. Insects can be prepared in many ways. Creative cooks can use them to cook protein-rich soup, make baked treats, and even fry a few with vegetables. So eat insects— both your body and Mother Earth will thank you for it!

Scientists based in Japan's Osakn University have found a way to3 D printed wagyu(和牛)beef in a lab--a step they believe will one day help make widely available and sustainably-produced cuts of cultured meat that closely resemble original products.

Using stem cells that they took from wagyu cows, the scientists set out to create a structure with the characteristic marbling seen in wagyu beef that sets it apart from other cuts of beef. By isolating beef cells, the scientists organized the muscles, blood vessels, and fat. The researchers then shaped these tissues into the form of a steak by using a technique called 3D bioprinting, where cell structures can be layered(分层)to resemble real tissues in living things.

Wagyu beef is known to be extremely expensive, with wagyu selling for up to $200 per pound and adult cows selling for more than S30, 000. In 2019, Japan's wagyu exports reached a record high of $268. 8 million in profits, up 20% from 2018. This might be the first cut of wagyu beef ever to be 3D-printed. The researchers believe that proving that a wagyu beef can be accurately 3D-printed could be a big step toward a sustainable future where cultured meat can be created that closely resembles existing products.

3D printed wagyu beef originates from real meat and is also different from plant-based options. "By improving this technology, it will be possible to not only reproduce complex meat structures, such as the beautiful marbling of wagyu beef but to also make small adjustments to the fat and muscle components, " Michiya Matsusaki, one of the project's researchers, said in a statement. Michiya Matsusaki added that with these adjustments, customers might one day be able to order a cultured cut of meat with the amount of fat they desire, tailor-made to their tastes and health concerns.

However, it might be a while before one can sink their teeth into a cut of bioprinted beef. The United States Department of Agriculture (USDA)and the Food and Drug Administration (FDA)have not created a regulatory framework for these products yet, according to The Washington Post.

What is better for you? Exercising in the great outdoors, or signing up for a gym? To try and find out, the guardian was invited to spend a month working with fitness and sports psychology experts at University of Bath and the National Trust. The concept was that participants—including me—would spend alternate weeks exercising in a gym and on National Trust land.

The first week was spent on the exercise bikes, rowing machines and treadmills (跑步机) in a gym at Bath. Getting started at the gym was easy. There was a nice community too. People are gently joking and encouraging each other.

On the downside, it was hard to ignore the background noise of dance and pop music. And all the machines faced screens showing music videos, rolling news and sports channels. Not a place to get away from it all.

So it was a relief in week two to head for the hills of Dyrham, a National Trust parkland full of birds and deer.

Weeks three and four followed the same pattern. The diaries I had kept, questionnaires I had filled in, and heart monitors I had worn, were then analyzed by scientists from University of Bath.

The findings surprise me a bit. The heart monitors showed I had consumed a similar amount of energy whether exercising in the gym or outdoors. But fitness expert Martyn Standage was most interested in the fact that on the days when my exercise had been done outside, I used more energy through the rest of the day. Standage said this fitted with studies that suggest working out in the outdoors leads to a greater feeling of vitality (活力).

Jo Barton, who specializes in studying outdoor exercise, suggested that working out in the fresh air

could be "life-changing". "Exercising in nature lifts your mood and increases your self-respect," she said.

My verdict? It was more fun outside but sometimes more convenient to get to the gym. A bit of both may be the way forward.

A study of 3, 884 students from primary schools to colleges found that examinations made 83. 1 percent of primary students anxious, and more than 40 percent of high school children were out of sorts (身体不适) because of stress and anxiety.

Moreover, 75 percent of the high school respondents admitted that they had problems talking to their parents and more than 55 percent of them found it hard to associate with other people, according to the study.

It is not difficult to conclude that our children are not happy.

Today's kids are coming home from school weighed down with backpacks full of books and worksheets. They are spending hours at a desk at night, seldom going outside to play and getting to bed late.

How can this be a good thing?

Homework is eating away children's time to play freely with neighborhood kids—and more importantly, their time to sleep.

Homework can enrich the education process. But like all things, too much of it may dampen (减少) a student's enthusiasm for learning. To raise cheerful, contented and well-mannered children, parents need to put in a lot of time and effort. Their eyes should go beyond their children's preparations for tests, Children need a break too. So let them be in control of parts of the day.

Facial recognition cameras are everywhere. Many people rely on this technology to unlock their phones open doors or make quick payments, but there is a problem :Everyone is wearing masks. What a hassle!

Now, tech companies have updated their software. Facial recognition technology can now recognize people even if they are wearing a mask. Beijing-based tech company Hanwang has announced a software that can correctly recognize 95% of people wearing masks, Engineering & Technology (E&T) reported. What's the secret? It's all about your eyes.

Marios Savvides, a professor at Carnegie Mellon University, US, studies facial recognition technology. As we get older, he said, our faces change shape, but not the area around our eyes. It stays the same -even if we put on weight. Another company, Geneva-based Tech5, has also been working on this kind of software. It has AI that measures the shape of your face. It also scans your irises(虹膜)and hopes to ignore all of the face below the nose. Japan's NEC Corp. claims an astonishing 99.9% accuracy rate when identifying people with masks. The UK's Metropolitan Police Service has been approved to buy and use NEC Corp.'s facial recognition technology, Forbes reported.

Facial recognition software is about more than just unlocking your phone. It's about public safety. For example, you don't need to present an ID card, which can be lost or stolen. It also means that germs aren't spread by touching things, said has NEC's Shinya Takeshima."Touchless verification(验证）has become extremely important due to COVID-19,"he said to Reuters.

"We hope to contribute to safety and peace of mind."

More than that, facial recognition can be used to fight crime. "It can detect crime suspects and terrorists,"said Huang Lei, Hanwang's vice president. Hanwang's technology is used by the police in high-security settings, Reuters reported. This means places like government buildings, subway stations and airports. Similar technology is used by the United States Air Force and other governments.

Huang Lei admits one big weakness of this technology: It fails when people wear both a mask and sunglasses."In this situation, all of the key facial information is lost, "Huang said to E&T.