In cities with rent control, the city government sets the maximum rent that a landlord (房东) can charge for an apartment. Supporters of rent control argue that it protects people who are living in apartment. Their rent cannot increase; therefore, they are not in danger of losing their homes. However, the critics say that after a long time, rent control may have negative effects. Landlords know that they cannot increase their profits. Therefore, they invest in other businesses where they can increase their profits. They do not invest in new buildings which would also be rent-controlled. As a result, new apartments are not built. Many people who need apartments cannot find any. According to the critics, the end result of rent control is a shortage of apartments in the city.

    Some experts argue that the minimum wage law can cause problems in the same way. The federal government sets the minimum that an employer must pay workers. The minimum helps people who generally look for unskilled, low-paying jobs. However, if the minimum is high, employers may hire fewer workers. They will replace workers with machinery. Therefore, other things being equal, the number of workers that employers want decreases. Thus, critics hold the opinion that an increase in the minimum wage may cause unemployment. Some poor people may find themselves without jobs instead of with jobs at the minimum wage.

    Supporters of the minimum wage say that it helps people keep their dignity. Because of the law, workers cannot sell their services for less than the minimum. Furthermore, employers cannot force workers to accept jobs at unfair wages.

    Economic theory predicts the results of economic decision, such as decisions about farm production, rent control, and the minimum wage. The predictions may be corrected only if “other things are equal”. Economists do not agree on some of the predictions. They also do not agree on the value of different decisions. Some economists support a particular decision while others criticize it. Economists do agree, however, that there are no simple answers to economic questions.

    A complaint was received by the president of a major car company:“This is the fourth time I have written to you , and I don't blame you for not answering me because must sound crazy, but it is a fact that we have a tradition in our family of having ice-cream for dessert after dinner each night. Every night after we've eaten, the family votes on which flavor(味道)of ice-cream we should have and I drive down to the store to get it. I recently purchased a new Pantsmobile from your company and since then my trips to the store have created a problem. You see, every time I buy vanilla(香草)ice-cream my car won't start. If I get any other kind of ice-cream, the car starts just fine. I want you to t now I'm serious about this question , no matter how silly it sounds: What is there about a Pantsmobile that makes it not start when I get vanilla ice-cream, and easy to start whenever I get any other kind?'

    The Pantsmobile company president understandably doubted about the letter, but he sent an engineer there anyway. The engineer had arranged to meet the man just after dinner time, so the two got into the car and drove to the grocery store. The man bought vanilla ice-cream that night and sure enough, after they came back to the car it wouldn't start for several minutes. The engineer returned for three more nights. The first night, the man got chocolate. The car started right away. The second night, he got strawberry and again the car started right up. The third night he bought vanilla and the car failed to start.

    There must be a reason why the man's car wouldn't start when he bought vanilla ice-cream. What was it? After doing more research into the case, the engineer eventually found out. The cause. Vanilla ice-cream was the most popular flavor and was on display in a little case near the express check out, while the other flavors were in the back of the store and took more time to choose and check out. This mattered because the man's car was experiencing vapor(蒸汽) lock, which is excess(过度的)heat boiling the fuel in the fuel line and the resulting air bubbles (气泡) blocking the flow of fuel until the car has enough time to cool. When the car was running, there was enough pressure to move the bubbles along, but not when the car was trying to start.

    Snorkelling in Silfra

The clear water at this UNESCO world heritage(遗产) site in Thingvellir National Park will leave you speechless. It is one of the highest rated dive sites in the world. During this journey, you will snorkel within a crack between the Eurasian and American continents. You'll experience truly amazing views of the colorful underwater landscape, marine life(海洋生物), and geological formations. Silfra's water is fresh and drinkable at around 2℃ - 4℃ all year round. Visibility can reach more than 100 meters, and swimming often feels more like flying.

    This trip is for anyone who knows how to swim and is up for a unique adventure. We offer transportation with a pick-up in Reykjavik, and provide you with a dry suit. The total length of the tour is approximately five hours, and includes in-water snorkelling lasting around 30 minutes. We'll guide you through the main Silfra Big Crack, Silfra Hall, Silfra Cathedral and Silfra Lagoon.

Included:

    All necessary snorkeling equipment;

    Hot drinks and food;

    Silfra entrance fee of 1,000 ISK.

    Availability: All year at 09:00 and 15:00. Pick-up in one hour before.

    Requirements:

    Participants need to complete the Silfra medical statement before the tour.

    Divers must:

    Be at least 18 years old (young people under 18 years old need a signature from their legal guardian), and the maximum age is 65 years old;

    Be able to communicate in English.

    Be physically fit;

    Not be pregnant;

    Not be under the influence of alcohol or drugs;

    Sign a medical form.

    The bristlecone pine (狐尾松) is one of the longest-living things on Earth. These trees, with their strangely shaped branches, can live up to 5,000 years, but experts worry that a warming climate in some areas may threaten its future.

    Researchers say warmer weather is permitting a similar kind of tree, the limber pine (柔枝松), to take over good growing places from the ancient bristlecone. They say the tree is being forced out of mountainous areas where it grows.

    Scientists at the University of California, Davis, say climate change is causing the trees to compete with each other.

    Brian Smithers led the research project. “The limber pine is taking all the good spots,” he said.

    Bristlecone pines grow in high mountain forests in eastern California, Nevada and Utah. In the mountains, they face high winds and extreme temperatures.

    The difficult conditions leave the trees with twisted(变形的) branches and shapes. To survive long periods without water, parts of the trees die, including much of their outer bark (外皮). This makes the trees appear dead, except for small green pine needles. They show that the tree is indeed alive.

    The oldest living bristlecone pine is somewhere in California. It is not marked in any special way, so that people do not try to damage it.

    The limber pine is the bristlecone's distant relative and competitor, which can also live a long time — up to 2,000 years. Researchers say it is found at lower elevations (纬度), where temperatures are warmer.

    The scientists at the University of California, Davis, recently released the results of a three-year study. Their research centered on trees that have started growing in the last 50 years in the Great Basin area of California's White Mountains. The researchers found that most of the trees growing at higher elevations were limber pines.

    Smithers said, “It's very strange to see it charging higher up and not see the bristlecone charging up the mountain slopes ahead of the limber pine.”

    Smithers said the bristlecones are not in danger of disappearing, but he thinks they could be forced out of some places where they have grown for thousands of years.

    Whenever we see a button, we are eager to press it because we know something will happen. This is true in most cases, for example on a doorbell and on the "on/off" button on the TV. But some buttons are actually fake, like the "close" button on a lift.

    Many people are in the habit of pressing the "close" button because they don't have the patience to wait for the lift doors to shut. But lifts "close" buttons are a complete scam, at least in the US-the doors will not close any faster no matter how hard you press.

    It started in the 199os when the Americans with Disabilities Act was passed in the US, making sure that all lifts stayed open long enough so that people with disabilities could enter. Only US firefighters and repairmen can use the buttons to speed up the door-closing process if they have a code or special keys.

    But to normal lift 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." Perceived（能够感知的）control is very important. It reduces stress and increases well-being," Ellen J. Langer, a psychology professor, said," Having a lack of control is associated with depression."

    Experts have revealed that a lot of buttons that don't do anything exist in our lives for this same purpose. For example, many offices in the US have fake thermostats（温度调节器）because people tend to feel better when they think they can control the temperature in their workspace.

    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, said," Even though I have real doubts about the traffic light buttons, I always press them. After all, I've got nothing else to do while waiting.  So why not press the button in the hope that this one will work?"

Everyone gets anxious when the world takes an uncertain turn. And often, we treat that anxiety with a little panic buying.

A study published last year in the Journal of Consumer Research found that people buy things in troubled times as a means of keeping control over their lives. The researchers noted that utility items — specifically, cleaning products — tend to move most quickly from store shelves. The hoarding (囤积) of toilet paper, as perhaps the most fundamental cleaning product, may represent our most fundamental fears. An invisible enemy moves slowly and quietly towards us. We need to hold on to something in uncertain times. Maybe a hoard of toilet paper brings promises.

The thing is, it's not actually going anywhere. For all the sharp words and even sharper elbows thrown around by the crazy toilet paper shoppers, they seem to be missing one essential fact: There is no toilet paper shortage.

As The New York Times points out, shop owners that see their shelves emptied often fill up the shelves again in a day, often in just a few hours.

"You are not using more of it. You are just filling up your closet with it," Jeff Anderson, president of paper product manufacturer Precision Paper Converters, tells the Times.

The thing is, the toilet paper-obsessed shoppers have been infected with something many times more contagious (感染性的) than any coronavirus: fear.

"People are social creatures. We look to each other for cues for what is safe and what is dangerous," Steven Taylor, a clinical psychologist at the University of British Columbia, tells Fox News. "And when you see someone in the store panic-buying, that can cause a fear contagion effect. People become anxious ahead of the actual infection. They haven't thought about the bigger picture, like what are the consequences of hoarding toilet paper."