For more than fifty years, a worker was forced to sit on the back of a truck and slowly drop plastic barriers（障碍） to set out lanes（车道）on the Golden Gate Bridge in San Francisco. Every day, their direction changes to control the traffic, meaning an employee had to go through the difficult task every twenty-four hours.

    But a new piece of machinery means the work can be completed in a matter of minutes. A new “zipper truck” has been introduced. The vehicle lays and moves a lane barrier as it drives over the bridge. Last weekend, the bridge was closed so the new safety barrier, designed to reduce the dangers of head-on crashes, could be set up.

    For the longest period in its nearly eighty-year history, the bridge was closed early Saturday to all but walkers, cyclists and buses to set up the barriers on the 1.7-mile bridge. A survivor of a 2008 head-on crash on the bridge spoke Sunday from a wheelchair to help introduce the new barrier, made of steel-clad concrete（铜包混凝土）blocks that can move across the bridge's six lanes to meet traffic needs.

    Gr. Grace Dammann pushed for a safer barrier since becoming unable to walk after the accident. She said she decided to drive near the middle of the bridge, which was called the “suicide（自杀）lane”, because she and her daughter were running late. Brian Clark, who was driving in the opposite direction, had just learned his father had cancer. “He suddenly lost control of the wheel, crossed over and hit my car,” Dammann said.

    She said she and Clark became friends as they persuaded（说服）the government to use the MYM30 million barrier. “I am so thankful,” said Dammann, who came to the ceremony with Clark.

    “Clark and I thank you.”

    This activity will melt away the pounds, build your body and leave you on an emotional high. Yet the form of exercise, the fitness trend of the year, does not require gym membership or a personal trainer. All you need to do is walk.

    “Walking is a refreshing alternative to complicated aerobic ( 氧) routines and overpriced gym membership,” says personal trainer Lucy Knight, author of a new book on the exercise. “It is free, enjoyable and already a part of everyday life. All you need to do is correct your technique, walk faster and for longer and you will lose weight.”

    There is much evidence of the benefits of walking. Scientists at the University of Pittsburgh recently discovered that overweight people who walked briskly ( 快) for 30 to 60 minutes a day lost weight even if they didn't change any other lifestyle habits. Another American study found that people who walked for at least four hours a week gained less weight than couch potatoes as they got older. Researchers at the University of Massachusetts medical school found that people who walked every day had 25 percent fewer colds than those who sat a lot. Best of all, walking makes you feel good about yourself. “For people suffering from depression, walking three to four times a week for 30 minutes has been shown to lift their mood,” says Knight.

    But how to walk your way to weight loss and wellness? Health experts recommend that we should walk 10,000 steps a day to stay healthy. Actually you would probably need to walk at least 16,000 steps a day to lose weight. “Your workout plans depend on your level of fitness. You should aim to progress by increasing your walking time by five minutes every two weeks, and walk a bit faster. In just three months, the results should speak for themselves,” says Knight.

    Long before iPhone, the cigarette was the companion of choice for restlessness. And long before Facebook and WeChat, it was tobacco that promised to better your social life. Now, quitting smartphones has become the new quitting smoking.

    Of course, technology does not yellow your teeth, cause disease or lead to cancer. But some individuals are so concerned that device addiction is damaging their mental health. In order to reduce their dependence, even in Silicon Valley, people are turning off the messages that constantly buzz for their attention, banning smartphones from the bedroom and, curiously, changing the colors on their screens to a less tempting scale of gray.

    The big tech companies will have to work out how to respond to this new generation of quitters. Facebook is the first to go public with its attempt, hoping its recent move can make the social network more homely.

Last year the tech industry got a bad name —Big Tech—with unfortunate echoes of other industries that have faced fierce opposition, including Big Tobacco. Like them, the tech industry has to reduce concern from a new generation of activist shareholders （股东） that are questioning its role in the world. These campaigns are never as fierce as those faced by Big Tobacco. In the 1990s, socially responsible investors refused to put money in tobacco stocks.

    It is far difficult for investors to challenge Big Tech and hard to separate the good these companies do in the world-connecting old friends and giving space for people to share their ideas-from the bad. In the meantime, stopping using technology remains problematic. In The World Without Mind: The Existential Threat of Big Tech, Franklin Foer argues that tech should be seen in a similar way to junk food: a convenience that some reject for more continuing nutrition.

    So we need to do more to turn the tide. In the same way that public service announcements made smoking around your children taboo （禁忌）, we can warn parents against losing themselves in their smartphones while taking care of kids. We can also create no-smartphone zones at dinner. Eventually smartphones could be banned from all public places and help us give our attention to the people around us instead.

    People love cellphones, which is why nine in ten Americans own one. But does heavy use of cellphones pose a risk of cancer? This question has caused controversy for many years. A new study in rats now augments those concerns. Its data linked long-term, intense exposure to radiation from cellphones with an increased risk of cancer in the heart or brain. The results have yet to be confirmed, the authors note.

    Indeed, although the rat study found a link between cellphone radiation and cancer, it offers no clues to why such a link might exist, notes Jonathan Samet. He teaches preventative medicine and directs the Institute for Global Health at the University of Southern California in Los Angeles. Still, he calls the new study's findings “significant”.They could lead to studies researching how cellphone radiation might cause cancer, he says.

    Phone signals are relayed between cell towers and cellphones via radio waves. This radio frequency—or RF—radiation is a type known as non-ionizing (非电离的).Unlike X-rays, non-ionizing radiation does not deposit enough energy into cells to release electrons from atoms or molecules, producing ions. So it tends to be far less harmful than ionizing radiation, such as X-rays. But that does not mean radio waves might not cause harm.

    In very large doses (量) this radiation will heat the body and cause tissue damage. But it's not yet known what much lower RF levels might do, such as those from cellphone use. Five years ago, the World Health Organization's International Agency for Research on Cancer, or IARC, concluded that cellphone use “is possibly carcinogenic (致癌的)”.

    Its conclusion was based on what little research data was available at that time. But notice that IARC was not certain. It said only that phone use might “possibly” cause cancer. So scientists at the National Toxicology Program, or NTP, investigated further.

    “Sorry seems to be the hardest word”—that is one of Elton Johns most popular songs. But not every public figure seems to find it so tough to say that powerful five-letter word.

    In recent days public figures, from politicians to stars, have all publicly expressed remorse. But with so much remorse, how can we tell a forced apology from a heartfelt expression of remorse?

    Specifically, saying sorry should be a realization that something you have said or done has hurt someone and you want to make amends. “People wants the response to be personal to them. They want to feel that they're being listened to and taken seriously,” says Martin Stone.

    Firstly, it is important to show that you understand. It is vital that any group or a person making an apology understands the focus—is it sorry for the way it's acted or is it sorry that the complainant feels the way they do? Watch out for the speed of response. The quicker the apology comes, the better it indicates that the person making it has felt an immediate sense of guilt.

    If sincere, the person making the apology will be looking for clues (线索) to see if he or she is being understood, such as eye contact and facial expressions. Performed apologies always have a sense of being “acted out”, and are often accompanied by too many unnatural gestures.

    For a sincere apology, it is also important to avoid promises that can't be kept. Don't say that you'll make sure that this will not happen again if you're not confident that it won't. It could come back to bite you. And do remember that the use of “but” can hugely change the tone (语气) of an apology. As Stone points out, “I'm sorry but…” sounds like you are making excuses and aren't actually taking any form of responsibility.

 Imagine this. You need an image of a balloon for a work presentation and turn to an AI text- to- image generator, like Midjourney or DALL-E, to create a suitable image. You enter the prompt(提示词)" red balloon against a blue sky" but the generator returns an image of an egg instead.

What's going on? The generator you' re using may have been" poisoned". What does this mean?

Text- to- image generators work by being trained on large databasets that include millions or billions of images. Some of the generators have been trained by indiscriminately (任意地) scraping online images, many of which may be under copyright. This has led to many copyright infringement(侵害) cases where artists have accused big tech companies of stealing and profiting from their work.

 This is also where the idea of" poison" comes in. Researchers who want to empower individual artists have recently created a tool named" Nightshade" to fight back against unauthorised image scraping. The tool works by slightly changing an image's pixels(像素) in a way that confuses the computer vision system but leaves the image unchanged to a human's eyes. If an organization then scrapes one of these images to train a future AI model, its data pool becomes" poisoned". This can result in mistaken learning, which makes the generator return unintended results. As in our earlier example, a balloon might become an egg.

 The higher the number of" poisoned" images in the training data, the greater the impact. Because of how generative AI works, the damage from" poisoned" images also affects related prompt keywords. For example, if a" poisoned" image of a Picasso work is used in training data, prompt results for masterpieces from other artists can also be affected.

 Possibly, tools like Nightshade can be abused by some users to intentionally upload" poisoned" images in order to confuse AI generators. But the Nightshade's developer hopes the tool will make big tech companies more respectful of copyright. It does challenge a common belief among computer scientists that data found online can be used for any purpose they see fit.

 Human rights activists, for example, have been concerned for some time about the indiscriminate use of machine vision in wider society. This concern is particularly serious concerning facial recognition. There is a clear connect ion between facial recognition cases and data poisoning, as both relate to larger questions around technological governance. It may be better to see data poisoning as an innovative(创新的) solution to the denial of some fundamental human rights.