After a terrible electrical accident, which caused him to become both blind and deaf, the whole world became completely dark and quiet for Robert Edwards for almost ten years. The loss of sight and hearing threw him into such sorrow(悲伤) that he tried a few times to put an end to his life. His family, especially his wife, did their best to tend and comfort him and finally he regained the will to live.

    One hot summer afternoon, he was taking a walk with a stick near his house when a thunderstorm started all at once. He stood under a large tree to avoid getting wet, but he was struck by the lightning. Witnesses thought he was dead but he woke up some 20 minutes later lying face down in muddy water at the base of the tree. He was trembling badly, but when he opened his eyes, he could hardly believe what he saw —— a plough and a wall. When Mrs. Edwards came running up to him, shouting to their neighbors to call for help, he could see her and hear her voice for the first time in nearly ten years.

    The news of Robert regaining his sight and hearing quickly spread, and many doctors came to examine him. Most of them said that he regained his sight and hearing from the shock he got from the lightning. However, none of them could give a convincing answer as to why this should have happened. The only reasonable explanation given by one doctor was that, since Robert lost his sight and hearing as a result of sudden shock, perhaps, the only way for him to regain them was by another sudden shock.

    Since English biologist Charles Darwin published On the Origin of Species in 1859, scientists have vastly improved their knowledge of natural history. However, a lot of information is still of the speculation, and scientists can still only make educated guesses at certain things.

    One subject that they guess about is why some 400 million years ago, animals in the sea developed limbs (肢) that allowed them to move onto and live on land.

    Recently, an idea that occurred to the US paleontologist (古生物学家) Alfred Romer a century ago became a hot topic once again.

    Homer thought that tidal (潮汐的) pools might have led to fish gaining limbs. Sea animals would have been forced into these pools by strong tides. Then, they would have been made either to adapt to their new environment close to land or die. The fittest among them grew to accomplish the transition (过渡) from sea to land.

    Romer called these earliest four-footed animals “tetrapods”. Science has always thought that this was a credible theory, but only recently has there been strong enough evidence to support it.

    Hannah Byrne is an oceanographer (海洋学家) at Uppsala University in Sweden. She announced at the 2018 Ocean Sciences Meeting in Oregon, US, that by using computer software, her team had managed to link Homer's theory to places where fossil deposits (沉积物) of the earliest tetrapods were found.

    According to the magazine Science, in 2014, Steven Balbus, a scientist at the University of Oxford in the UK, calculated that 400 million years ago, when the move from land to sea was achieved, tides were stronger than they are today. This is because the planet was 10 percent closer to the moon than it is now.

    The creatures stranded in the pools would have been under the pressure of “survival of the fittest”, explained Mattias Green, an ocean scientist at the UK's University of Bangor. As he told Science, “After a few days in these pools, you become food or you run out of food... the fish that had large limbs had an advantage because they could flip (翻转) themselves back in the water.”

    As is often the case, however, there are others who find the theory less convincing. Cambridge University's paleontologist Jennifer Clark, speaking to Nature magazine, seemed unconvinced. “It's only one of many ideas for the origin of land-based tetrapods, any or all of which may have been a part of the answer,” she said.

    People with bigger brains tend to score higher on standardized tests of intelligence, according to new study findings.

    However, the study author Dr. Michael A.McDaniel of the Virginia Commonwealth University in Richmond emphasized that these findings represent a general trend, and people with small heads should not automatically believe they are less intelligent. For instance, Albert Einstein's brain was "not particularly large", McDaniel noted." There's some relationship between brain size and intelligence on the average, but there's plenty of room for exceptions," he said.

    Interest in the relationship between brain size and intelligence grew in the1830s, when German anatomist(解剖学家) Frederich Tiedmann wrote that he believed there was "an unquestionable connection between the size of the brain and the mental energy displayed by the individual man". Since that statement, scientists have conducted numerous studies to determine if Tiedmann's assertion was correct. Most studies have looked into the link between head size and intelligence. More recently, however, researchers have published additional studies on brain size and intelligence, measured using MRI scan(核磁共振成像扫描).

    For his study, McDaniel analyzed more than 20 studies that looked into the relationship between brain size and intelligence in a total of 1,530 people. The studies showed that on the average, people with larger brain volume tended to be more intelligent. The relationship between brain volume and intelligence was stronger in women than men, and in adults than in children. McDaniel notes in the journal Intelligence.

    McDaniel is not sure why the relationship was stronger for adults and women. "Other research has shown that women, on the average, tend to have smaller brains than men, but score just as well—if not higher—in tests of intelligence," he said.

    McDaniel insisted that the relationship between brain size and intelligence is not a "perfect" one. "One can certainly find lots of examples of smaller-sized people who are highly intelligent," he said, "But, on the average, the relationship holds."

    From July to October every year, about a quarter of the world's blue whales feed in the Pacific Ocean off the coast of California. But the whales currently face a major threat in their favorite feeding area. Ships carrying cargo （货物）sail in the same area at the same time. All too often, the whales' paths and the ships' travel lines overlap (重叠), and a ship will hit a whale.

    According to a new study, these ship strikes have become a serious threat to the overall population of the world's blue whales. Only about 10,000 of the creatures still exist worldwide. Blue whales are the largest known animals ever to live on Earth. Even so, if hit by a container ship, a blue whale will likely die from its injuries.

    In 2007 alone, large ships killed five blue whales in the waters off San Francisco and Los Angeles, California. The National Oceanic and Atmospheric Administration (NOAA) says that because there are so few whales already, losing three to five from the California whale population every year is a significant loss. "The estimated population of blue whales in this part of the Pacific is 2,500", says Sean Hastings, a NOAA analyst. "So every whale counts toward this species moving off the endangered-species list."

    Now, marine scientists must figure out how to protect the whales from the giant container ships. One very simple program is already under way in the Santa Barbara Channel, a waterway that separates mainland California from the nearby Channel Islands.

    The Channel Islands National Marine Sanctuary has asked large container ships passing through the area to voluntarily slow down. Sailing slower will allow the ships crew （船员）more time to change course before hitting a whale.

    Several of the world's largest shipping lines are set to participate in the new program. For every ship that passes through the Santa Barbara Channel at or below the reduced speed of 12 knots （海里/小时）, the company that owns the ship will be paid $2,500.

    Inspired by a 9-year-old cyclist, Lauren Turner, who can only use one hand, a group of University of Guelph students has won an international award for their invention — a bike brake lever (刹车手柄) that pulls both the front brake and the back brake at the same time.

    Lauren Tuner was able to ride her bike, but not as confidently and quickly as her friends.

    "She couldn't use the front brake. She only used the back brake, but the front brake makes you stop twice as fast," says Micha Wallace, who, with Katie Bell, Anina Sakaguchi and Andrew Morries won second prize in the James Dyson Award for their single-handed bike brake lever.

    "Lauren Turner tried the device (装置) first and she used it all last summer. She had no problems. It helped her go faster because she felt more confident in her braking abilities. She felt safer." says Wallace.

    The invention was the fourth-year design project for the four students. They designed, tested and created a prototype (模型) within a four-month period.

    When Wallace heard about the James Dyson Award on the news, she and her co-inventors entered their project in the U. K. -based contest, which rewards students designers who create products that improve the way we live. The students collected the runner-up prize — £2,000 for them and £500 for their school.

    As well, they had a chance to meet James Dyson, a U.K. famous inventor. Praising the students for their invention, Dyson says the single-handed brake lever could improve safety for all cyclists. By using both brakes at once, you could prevent the possibility of flying over the handlebars and ending up with an injury.

    The students hope to sell it to a major company. It may be used in other devices that require two hands for operation.

    Humans and many other mammals have unusually efficient internal temperature regulating systems that automatically maintain stable core body temperatures in cold winters and warm summers. In addition, people have developed cultural patterns and technologies that help them adjust to extremes of temperature and humidity (湿度).

    In very cold climates, there is a constant danger of developing hypothermia, which is a life-threatening drop in core body temperature to below normal levels. The normal temperature for humans is about 37.0℃. However, differences in persons and even the time of day can cause it to be as much as 6℃ higher or lower in healthy individuals. It is also normal for core body temperature to be lower in elderly people. Hypothermia begins to occur when the core body temperature drops to 34.4℃. Below 29.4℃, the body cools more rapidly because its natural temperature regulating system usually fails. The rapid decline in core body temperature is likely to result in death. However, there have been rare cases in which people have been saved after their temperatures had dropped to 13.9-15.6℃. This happened in 1999 to a Swedish woman who was trapped under an ice sheet in freezing water for 80 minutes. She was found unconscious, not breathing, and her heart had stopped beating, yet she was eventually saved despite the fact that her temperature had dropped to 13.7℃.

    In extremely hot climates or as a result of uncontrollable infections, core body temperatures can rise to equally dangerous levels. This is hyperthermia. Life-threatening hyperthermia typically starts in humans when their temperatures rise to 40.6-41.7℃. Only a few days at this extraordinarily high temperature level is likely to result in the worsening of internal organs and death.