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    The Americans believe that anybody can become president of the United States. In a recent Hollywood comedy, that is exactly what happens.

    Dave Kovic, played by Kevin Kline, is a kind-hearted man who runs a business that finds people jobs. He leads a typical American way of life, except for one thing－he looks exactly like the president, Bill Mitchell. In fact, the only thing that makes him different from the nation's leader is that he is very nice!

    The president has started using look-alikes during some public appearances. Dave is offered a chance to “serve his country” by becoming one. However, things go wrong. The president becomes very ill and Dave ends up acting as the president forever.

    Director Ivan Reitman, who made the popular and successful comedies like Twins, Ghostbusters and Legal Eagles, could have gone for easy laughs by making fun of the American government. Instead, Dave is an attractive comedy about an ordinary man in extraordinary situations. Kevin Kline gives a double performance as Dave and the president, and Sigourney Weaver is at her best as his First Lady. The love story that develops between her role and Dave is a real classic.

    The film is 100% American. However, if you've ever felt that anybody could do a better job running the country than the people in power, then you'll enjoy Dave!

    When my friend Lesa was diagnosed(诊断) with cancer, another friend and I went to the hospital to spend some time with her. We bought her a small toy and  named him Lemon－Aide. We gave Lemon－Aide to Lesa and told her he was to go with her to all of her treatments to remind her that we were thinking of her and caring about her even though we could not always be with her. When the treatments were completed, she said when someone else needed him she would pass him along.

    A few months later，much to my surprise, it was me that she passed him to. Lemon－Aide went with me to all of my treatments.

    One day while waiting for my doctor I decided we could market the idea to fight cancer. Lesa thought it was a great idea so we founded the organization that came to be known as Lemon－Aide' s Friends, Inc. We designed our organization to remind people fighting cancer that there are people who love and care about them all the time. Today we have totally 5013 volunteers. The money raised is donated to cancer patients who do not have insurance. The physicians on our Board of Advisors determine how and where our money is donated.

    Lemon－Aide is for men, women, and children of all ages and to date has been sent to 34 states and 33 countries to provide smiling support for people fighting cancer. When life gave us lemons we made Lemon－Aide, a soft smiling toy that represents love, support, and encouragement.

A hybrid electric vehicle (混合动力车) or HEV is a vehicle driven by the combination of petrol engine and electric motor. Terrence has been driving a HEV for five years. He really doesn't understand why more people aren't accepting them. "I probably spend about $ 7 a day on petrol," the taxi driver told news. com. au. In his previous conventional vehicle Terrence said he was spending up to $ 30 a day on petrol, meaning he saves almost $ 6000 every year.

The Toyota spokesman said this was quite a high saving and official tests estimate (估计) an average driver would only save about 33 percent off their current bill. This means a driver paying $ 30 a day on petrol would see their bill drop to about $ 20 using the hybrid. "A taxi driver that drives in built-up areas and spends little time on highways will notice a higher fuel saving," he said. "Low speeds allow the electric motors to be used more and the petrol engine used less."

While some people are skeptical about how reliable hybrids are, Terrence said he had never run out of power. His Camry cost about $ 34,000 and so after five years, it's nearly paid for itself. "For cab drivers, it's a real advantage because of the cost-effectiveness," he said. Terrence has no complaints about the car. "I love it, the calm and quietness of it, the simplicity of it—you just jump in and go. The maintenance（保养）is really low. But the only difficulty is finding someone to service the car as there are not many experienced mechanics（机修工）."

Terrence said it's "extraordinary" that more drivers aren't buying more hybrid electric vehicles and that governments are not encouraging this more. "I think people have a view that you have to plug it in, which is not true. A lack of information about the cars may be stopping people from taking the plunge. It's not promoted at all for the public to understand—it's simplifying the actual owning of a car—you don't have to do so many things to own it and run it, it's just so much simpler. Why wouldn't the government promote such a thing?"

    The Harvard Pre-College Program is a nice experience for high school students. Alongside peers(同辈)from around the world, you'll be introduced to college life as you attend classes, live on campus, and enjoy fun outings and activities.

    Learning without limits

    Biology, physics, law, writing and philosophy — these are just a few of the 30-plus courses you can choose from in each session. In our noncredit classes, we set aside grades so that you can fully commit to your growth as a well-rounded student. Class sizes typically range from 14 to 18 students to encourage interactive learning.

    Living at Harvard

    When you attend the Pre-College Program, you'll live in a historic undergraduate house, near Harvard Square. You will be with your fellow Pre-College students, resident directors, and proctors who provide support. You'll also enjoy meals in one of Harvard's dining halls, which are a short walk from Harvard Yard and provide many options for a variety of dietary needs.

    Thriving outside the classroom

    The summer Pre-College Program offers many mentally challenging co-curricular(补充课程的)activities beyond the classroom. With faculty and Harvard-affiliated experts, you will have the opportunity to participate in workshops on topics like the psychology of color-blindness, classic literature from around the world and science of happiness. From our Cambridge scavenger hunt to a trip to the Sand Sculpting Festival at America's first public beach, there's no shortage of fun activities in the Pre-College Program.

 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.