A new study finds almost one third of the world's population is overweight. Since 1980, obesity rates(肥胖率)in children and adults have doubled in 73 countries, making people more worried. And rates are increasing in many other countries. Obesity is increasing faster in children than adults in many nations, including Algeria, Turkey and Jordan, the report said. But the world's weight problem is growing in both rich and poor countries alike. Researchers say an increasing number of people are dying of related health problems in what they called a "disturbing global public health problem."

    Researchers studied health information from 1980 through 2015. They examined obesity rates, average weight gain in 195 countries. They found that obesity rates are three times greater among youth and young adults in countries like China, Brazil and India. Almost 108 million children and more than 600 million adults were found to be overweight. Egypt had the highest number of overweight adults in 2015. Vietnam had the least. In the same year, the United States had the highest number of overweight children, and Bangladesh had the least.

    Yet hunger remains a problem in many areas. The United Nations said that almost 800 million people, including 300 million children, go to bed hungry each night. Experts said poor diets and lack of physical activity are mainly to blame for the rising numbers of overweight people.

    Growing populations have led to rising obesity rates in poor countries. Often, poor people will eat processed(加工的) foods instead of choosing a diet rich in vegetables.

    The London-based Overseas Development Institute studied the price of food in five countries: Britain, Brazil, China, Mexico and South Korea. It found that the cost of processed foods like ice cream and hamburgers has fallen since 1990. But the cost of fresh fruits and vegetables has gone up.

    Whenever we see a button on a doorbell or on a remote, we may press it. This is true in most cases. But some buttons are actually fake(假的), like the "close" button on an elevator.

    Many people are in the habit of pressing the "close" button because they don't have the patience to wait for the elevator doors to shut. But according to experts, the buttons are a complete trick—the doors will not close any faster however hard you press.

    It started in the 1990s when the Americans with Disabilities Act was passed, making sure that all elevators stayed open long enough so that people with disabilities could enter. Only firefighters and maintenance workers(维修工) can use the buttons to speed up the door-closing process if they have a code or special keys. But to normal elevator riders, the buttons aren't completely useless.

    According to psychologists, fake buttons can actually make you feel better by offering you a sense of control. Experts have showed that a lot of buttons that don't do anything exist in our lives for this same purpose. For example, pedestrian crosswalk buttons don't live up to their names. Pressing them used to help make the traffic signals change faster, but that was before computer-controlled traffic signals were introduced.

    But psychologists found it interesting that even when people are aware of these little "white lies". They still continue to push fake buttons because as long as the doors eventually close, it is considered to be worth the effort.

    That habit is here to stay, John Kounios, a psychology professor at Drexel University in the US, told The New York Times. "After all, I've got nothing else to do while waiting. So why not try the chance?"

    Depression(抑郁) can be a destructive illness, plaguing millions of people worldwide with feelings of sadness, hopelessness, and fatigue. Despite numerous antidepressant drugs, as many as a third of patients don't respond to medication. This has forced doctors to be more creative in finding different treatments for the condition.

    In the past two decades, researchers have tied depression to a seemingly unrelated condition: inflammation(炎症), the body's natural response to stress. It could rise from injury or inflection, or even emotional issues like an unhappy marriage or problems at work. Some amount of inflammation is generally beneficial, as it increases production of cytokines(致癌因子)，proteins that help us heal and protect us from the effects of overwork.

    But excessive cytokine levels, and the inflammation they bring on, could come at a cost—a number of studies suggests that high levels of cytokines could contribute to depression.

    Cytokines can reach the brain several ways: directly through the blood-brain barrier or indirectly by binding to nerve fibers elsewhere, which send signals to the brain to produce the inflammation molecules. In the brain, cytokines can disturb the production and release of several important signaling chemicals, including serotonin, dopamine and glutamate, which help control emotion, appetite, sleep, learning and memory. It's though that a lack of serotonin activity in the brain causes depression; most antidepressants increase the activity. But cytokines also have been shown to activate stress hormone signaling in the brain, which man also serve to develop depression.

    With all the evidence implicating inflammation in depression, doctors have been anxious to test anti-inflammatory drugs as a potential treatment. Four small studies published between 2006 and 2017 by research groups in Europe and Iran found that adults diagnosed with depression who took aspirin or another anti-inflammatory drug called Celecoxib, along with an antidepressant, got more relief from feelings of sadness, hopelessness, guilt and fatigue compared with those taking an antidepressant alone. However, Andrew Miller, a professor of psychiatry at Emory University, thought something was wrong in these small, limited studies. None of them looked at whether the participants had to have high levels of cytokines before they'd see a benefit from anti-inflammatory drugs.  "Unfortunately, much of the field has fallen into the trap of viewing inflammation as the be-all, end-all," Miller says. He and his colleagues wanted to see whether the effect of these drugs was limited to the depression patients with high cytokine levels, or if it helped all people diagnosed with depression.

    Whales, like all mammals(哺乳动物),need air, and come to the surface to breathe through a blowhole. A drone(无人机)that floats over the blowholes of humpback whales as they are making annual journey along Australia's east coast is being used by Australian scientists for collecting nasal mucus(鼻腔粘液)of whales.

    Vanessa Pirotta, a biologist at Macquarie University says that nasal mucus indicates the health of the whale. "It is the biological mixture that you see as a whale takes a breath as it surfaces from the water," she said. You can hear sounds of sharp breaths as a whale breathes because, after all, they are animals like you and I. So as they take a breath it is a lot of lung bacteria coming out from their lungs, which we can collect to provide a brief idea of whale health.

    Australian researchers have attached a special dish that is used in scientific tests to a drone which flies through the whale's nasal mist. As a whale comes to take a breath—you can actually see it coming to the surface on really good weather days —the drone then lowers, the dish is then opened, collecting nasal mucus for later research.

    The research could help to solve one of the secrets of another impressive creature of the deep —the Southern right whale. Its numbers have recovered on Australia's west coast since hunting became suppressed but its population on the eastern seaboard remains stubbornly low.

    In the past, studies into whale health had to rely on examining whales that were either killed or those whales that had been trapped on a beach. Drones allow scientists to collect nasal mucus from free-swimming whales to gather information in a safe way.

    The Internet has completely changed the workplace over the past three decades. Artificial Intelligence is now all set to do the same, and businesses that don't take advantage of the technology risk being left behind.

    Global tech giants (巨头) like Amazon have been leading the change, and businesses of all sizes are now using the technology for employing and managing their staff.

    Among them is L'Oreal. With about a million applicants for roughly 15,000 new positions each year, the company is using AI to hire.

    “We really wanted to save time and focus more on quality, diversity and candidate experience. And AI solutions were the best way to go faster on these challenges, said Eva Azoulay, global vice-president of L'Oreal's Human Resources Department.

    The company uses Mya, a chatbot, to save employers' time during the first stage of the process. It handles routine questions from candidates, and checks details such as availability and visa requirements. Should candidates make it to the next round, they'll run into Seedlink, an AI software that scores applicants based on their answers to open-ended interview questions. These scores don't replace human judgment, said Azoulay, but they do pick out candidates who might not seem like obvious choices.

    Early results have been promising. For one internship program, where 12,000 people apply for about 80 spots, employers claim they saved 200 hours of time while hiring the most diverse group to date.

    Other businesses have gone beyond employment and are using AI to help manage employees. Some UK firms have started using Isaak, a system designed by the London-based company StatusToday, to track how many hours staff spend online and the number of emails they receive. London real estate agent JBrown has been using this system since March. CEO James Brown said it helps the firm understand employees' habits and prevent them from overworking. "It enables us to solve bottleneck problems and relieve overburdened employees," he said.

    Despite these examples of good practice, there is still a long way for AI to reach its full potential (潜力), and the technology comes with risks. Another AI danger could be its impact on jobs through automation (自动化). McKinsey predicts AI could add $13 trillion to the global economy by 2030, with early adopters doubling their cash flow over that period. But the demand for repetitive (重复的) or digitally-unskilled jobs could drop by around 10%, the consulting firm said in a 2018 report.

When it comes to architectural accomplishments, humans like to think they stand at the top. That is to underestimate the astonishing achievement s of social insects; for example, white ants raise skyscraping nests. The true master builders of the insect world, however, are the hundreds of species of stingless bees.

In a new study, Ms. Di Pietro and her colleagues observed over 400 colonies of the stingless bee species in a large bee house in Brazil in 2022 and 2023. Around 95% of the colonies exhibited honeycombs（a structure made by bees） built up in horizontal layers（水平分层）, like tiered wedding cakes, while the rest adopted a spiral（螺旋的） structure.

Since the stingless bee shows a strong preference for a horizontal-layer honeycomb structure, it's surprising that spiral honeycombs occur. The team confirmed that there was no difference in the average cell-building rate between the two styles, and therefore no efficiency advantage.

In order to rule out a genetic explanation for the different styles, the researchers transplanted workers from colonies that built in one tradition to colonies that built in the other, having first emptied the host structures of their native adults. The imported workers soon switched to the local style, which was then continued by the colony's young insects as they eventually matured into workers.

Dr. Tom Wenseleers guessed that the bees may switch styles as a way of coping with the build-up of small construction errors made by their fore-runners. Such a process, in which multiple organisms indirectly affect each other's behavior through the traces they leave in their environment, is known as stigmergy（共识主动性）. The researchers later introduced a sign of spirals to the otherwise perfect horizontal-layer honeycombs, and found that it did indeed cause the bees to switch to building spirals.

These results suggest that stingless bees can pass on different building traditions across generations and individuals needn't be instructed by their peers. "The findings are the clearest demonstration of cultural differences naturally appearing in insects. Insect culture would once have been thought impossible," says behavioral biologist Andrew Whiten, who wasn't involved in the research. "Less than a century ago, culture was thought to be uniquely human."