Radiocarbon dating has revealed two fake (伪造的) paintings in France — probably the first time the technique has been used in a police investigation. The paintings were supposedly works from around the early twentieth century. But a team led by scientist Lucile Beck at the University of Paris-Saclay dated them to sometime within the past 70 years.
The use of radiocarbon dating is gaining popularity, thanks to advances that require smaller samples than ever before. Removing tinier samples from artwork is becoming more palatable to museums and owners of paintings. If there is a chance that a painting is genuine — and therefore valuable — they don’t want the collection of larger samples to damage it.
All living things take in carbon, including radioactive carbon-14, from the atmosphere and from food. When a plant commonly used to make oil painting cloth dies, the carbon-14 that it contained continues to fall off. Radiocarbon dating measures what’s left to estimate the time that’s passed, says Mariaelena Fedi, a physicist at the National Institute for Nuclear Physics in Florence, Italy.
Atomic-bomb (原子弹) testing, which began in the 1940s and took off in the 1950s, quickly increased the amount of carbon-l4 in the atmosphere.Carbon-l4 peaked around 1964and went down after a partial ban on nuclear tests. Researchers can easily identify materials containing modern bomb-produced radiocarbon because their carbon-14 concentrations are higher than pre-1950s levels. Beck’s team tested its samples to see whether they bore the feature of that bomb-produced radioactive carbon-14.
The canvas fiber from the paintings clearly contained carbon from either the mid-1950sor after the year 2000, the researchers reported. Beck acknowledged that, ideally, the team would do further chemical analysis to support its findings, but the researchers were limited by the tight time.
1. What does the underlined word “palatable” in Paragraph 2 probably mean?| A．Impressive. | B．Acceptable. | C．Expensive. | D．Difficult. |
| A．By analyzing samples from artwork. |
| B．By removing the smaller samples. |
| C．By measuring the carbon-14 left. |
| D．By testing the carbon in the sample. |
| A．It produces more carbon-14. |
| B．It helps identify fake paintings. |
| C．it reduces carbon concentration. |
| D．It has been stopped completely. |
| A．Paintings waiting to be identified |
| B．Two fake paintings found in France |
| C．New technology in painting becomes a hit |
| D．Radiocarbon dating proves an anti-fake helper |
相似题推荐
【推荐1】Countries around the world are spending plenty of dollars and lots of time on various space tasks.
Space exploration has already enhanced technological improvements that benefit us all. High-end products around the world are made to a higher standard. Today space technologies are widely used in all kinds of industries.
Sending astronauts (宇航员) into space has helped people think about the world’s problems and find ways to solve them. Our planet’s resources are limited. In order to provide for the rapidly increasing population, scientists are trying to find other planets that could one day be our new home.
Exploring space benefits us so much. So it should be continued so as to provide new and better solutions to people’s short-term and long-term problems.
| A．Then the data is sent to scientists on the earth. |
| B．Exploring space brings many difficulties to the world. |
| C．Some people think we should realize how exploring space helps us. |
| D．The greatest attention at present is on Mars because it is closer to the earth. |
| E．Some people argue we should stop wasting time and money exploring space. |
| F．Exploring space has already made a difference in the fight against world hunger. |
| G．Smartwatches, memory pillows, smartphone cameras and so on are changing our lives. |
【推荐2】Age may be just a number, but it’s a number that often carries unwanted side effects, from fragile bones and weaker muscles to increased risks of heart disease and cancer. Now, scientists at the Salk Institute have shown that they can safely and effectively reverse the aging process in middle-aged and elderly mice by partially resetting their cells to more youthful states.
As living creatures age, it is not just their outward appearances and health that change; every cell in their bodies carries a molecular clock (分子钟) that records the passage of time. Cells from older people or animals have different patterns of chemicals along their DNA, called epigenetic markers (表观遗传标志物), compared to younger people or animals. Scientists know that adding a mixture of four reprogramming molecules — also known as “Yamanaka factors” — to cells can reset these epigenetic markers to their original patterns. This approach is how researchers can dial back adult cells, developmentally speaking, into stem cells (干细胞).
In the new study, Izpisua Belmonte, a professor in Salk’s Gene Expression Laboratory, and his colleagues tested variations of the approach in healthy animals as they aged. The first group of mice received the Yamanaka factors from the time they were 15 months old until 22 months, approximately equal to age 50 through 70 in humans. Another group was treated from 12 through 22 months, approximately age 35 to 70 in humans. And a third group was treated for just one month at age 25 months, similar to age 80 in humans.
“What we really wanted to establish was that using this approach for a longer time is safe,” says Belmonte. “Indeed, we did not see any negative effects on the health, behavior or body weight of these animals. ” Compared to control animals, there were no blood cell changes in the mice that had received the Yamanaka factors. Moreover, the team found no cancers in any of the groups of animals.
1. What does the underlined word “reverse” in Paragraph 1 probably mean?| A．Maintain. | B．Start. | C．Change. | D．Quicken. |
| A．They consist of four reprogramming molecules. |
| B．They can turn epigenetic markers into stem cells. |
| C．They have been applied to lower the risk of heart disease. |
| D．They were discovered by Izpisua Belmonte and his colleagues. |
| A．The purpose of the study. | B．The procedure of the study. |
| C．The background of the study. | D．The significance of the study. |
| A．To report the result of a cancer study. |
| B．To introduce a cure for aging diseases. |
| C．To inform a breakthrough in gene research. |
| D．To explain the process of keeping mice young. |
【推荐3】Coaches have always taken into account the condition of players when scheduling training sessions. Now with the help of artificial intelligence, they can calculate more precisely the probability that individual athletes will get injured during the next match, the next week or the next month.
“We follow a team for an entire season, recording GPS data during training and matches,” Rossi explains. He then uses machine learning to try to detect patterns. “This gives us the probability that a player will get injured in the next days or next weeks.”
These data reveal an athlete’s workload—how often they train and how intensely. Just enough training can pave the way to medals, but too much puts pressure on the body and can lead to injuries.
Sport is gradually entering a new era, in which artificial intelligence might act as an assistant coach. Algorithms (算法) could enable a teenager to train smarter and avoid a career-ending injury or help a professional athlete to compete for a new years longer. But the technology’s success depends, in part, on the ability of data scientists to convince coaches to include data in their decision process.
The teams that McHugh has worked with have seen a reduction in injuries of between 5% and 40%. Yet not every coach is happy to join forces with AI. “Coaches sometimes don’t feel good, because it seems like trying to substitute the human element,” Rossi says. But in reality, data is only a tool. “The interpretation of the results, the change of the training load, is done by coaches,” he says.
McHugh agrees that people have to make the final call. “Once the injury probability for an athlete on a given day is output from an injury model. The athlete or coach must then decide whether the predicted risk is acceptable or not, usually depending on the context,” he says. There might be a big game that day, and the player might be especially important to the team. “Even though the predicted injury probability may be as high as 70%, the coach may be willing to take that chance he says.
1. What can be learned about GPS data?| A．GPS data decide athletes’ workload. |
| B．GPS data are collected during the final match. |
| C．GPS data use machine learning to detect patterns. |
| D．GPS data provide useful information for training athletes. |
| A．Athletes’ training time. | B．Coaches’ acceptance. |
| C．Scientists’ judgment. | D．Data accuracy. |
| A．AI in sports has a bright future. |
| B．The coach tends to ignore the risk. |
| C．It is up to people to make the final decision. |
| D．It is always wise to follow the advice of AI. |
| A．Replacing coaches with AI | B．Predicting Injuries with an algorithm |
| C．Training athletes intensely | D．Embracing technology readily |
【推荐1】Digital assistants such as Siri are increasingly common on phones and computers. Developing an emotional relationship with a piece of software can, however, bring discomfort to some people.
As a study published in Psychology Science by Park Daeun, of Chungbuk National University in South Korea, and her colleagues, shows, one emotion sometimes involved in machine-human interaction is embarrassment.
Dr. Park and her team recruited 187 participants into their study. To start with, each was presented with a series of statements on the changeability of intelligence. These included, “you have a certain amount of intelligence, and you can’t really do much to change it”, and “you can always substantially change how intelligent you are”. Participants rated their responses to these statements on a six-point scale, on which one meant “strongly disagree” and six meant “strongly agree”. The reason for this initial test was that Dr. Park knew from previous work that those who believe intelligence to be changeable are comfortable asking for assistance while those who believe it to be fixed often feel ashamed to do so.
The initial test done, the researchers presented their volunteers with a second, which involved looking at 16 sets of three words and trying to think of a fourth word that linked them. For example, when offered “room, blood, salts” a correct answer would be “bath”. Sometimes the first three words were accompanied by an unrequested hint (in the example given, this was “tub”). Sometimes they were not.
Hints appeared as the written form of the word in question, accompanied by a computer-shaped icon (图标). For half of participants this icon had a humanlike face, and the hint was placed inside a speech bubble originating from that face, thus anthropomorphizing (赋予人性) the presentation to some degree. For the other half the icon lacked a face and there was no speech bubble. After the final set of words had been displayed, participants were asked to agree to disagree with follow-up statements about their experience, such as “it was embarrassing to receive help during the task”, and “others might think I am incompetent (无能的) because I received help during the task”. This time, they quantified their feelings on a seven-point scale, with higher scores representing greater feelings of unease.
The researchers found that participants who believed intelligence to be unchangeable (the top sixth of the sample) felt more embarrassed and more incompetent after the tests. They averaged 3.2 when measured for feelings of shame and embarrassment if the computer icons they had seen giving the hints had had faces and speech bubbles but only 2.7 if not. In contrast, people who strongly believed that intelligence could be changed over time (the bottom sixth of the sample) felt the same level of discomfort (around 2.5) whether or not the icons had been anthropomorphized.
1. The initial test is meant to classify the participants according to ________.| A．how intelligent they are in academic settings |
| B．how familiar they are with previous research |
| C．how much they agree with Dr. Park’s viewpoint |
| D．how much they believe intelligence is changeable |
| A．request a useful hint at a proper time |
| B．link the four words given with a key word |
| C．tell computer-shaped icons from face-shaped ones |
| D．answer whether they feel comfortable to receive help |
| A．Those believing intelligence can change are more likely to turn down computer’s help |
| B．Those regarding intelligence as fixed may feel less at ease when turning to computers. |
| C．Those regarding intelligence as fixed are more likely to feel embarrassed in real life |
| D．Those who believe intelligence can change are more capable than those who don’t. |
| A．More should be done to make digital assistants more human-like. |
| B．People’s idea of intelligence needs to be updated at the moment. |
| C．Digital assistants are sometimes too human to appeal to users. |
| D．Embarrassment is among most common emotions people have. |
【推荐2】While we aim to avoid any appearance of baseless theories, it is noteworthy to observe the long-standing practice of putting magnets (磁铁) in cows, a phenomenon that has been carefully unfolding for years. Why are farmers putting magnets in cows?
Known as cow magnets, the devices are placed inside cattle to deal with “hardware disease”. Hardware Disease occurs after an animal eats a metallic object that then makes a hole in the wall of the reticulum, the second stomach room in ruminant animals (反刍动物). This issue arises from the natural eating behaviors of these ruminants, similar to a person at an unlimited food event — quickly and eagerly large bites without sufficient chewing. This fast-paced feeding approach makes them tend to unintentionally consume metal pieces in their food, including broken farm machinery parts, nails and wires used in fencing, for instance.
Metal objects entering the reticulum may result in infections, increased body temperatures, digestive problems, and unease for the animals. To address hardware disease, the main strategy is to prevent metal from entering the cattle’s diet. Farmers have also adopted the method of placing cow magnets into the stomach using either a stomach tube or a balling gun. The cow magnet attracts such objects and prevents them from becoming fixed in the animal’s tissue. These magnets, once positioned, remain within the animals throughout their lifespan, only being removed after death when the cows pass away or are processed for meat.
Moseley, a Veterinary Medicine professor, states in a hardware disease resource, “The magnet gathers foreign metallic objects, reducing the risk of making a hole in the reticulum.” Research shows a mild magnetic field affects a cow’s small blood pathways, improving circulation and aiding recovery without significant impact on the cow or milk quality.
1. Why are magnets fed to cows?| A．To change feeding habits. | B．To prevent hardware disease. |
| C．To improve the milk quality. | D．To enhance digestive system. |
| A．Eating without chewing. | B．Taking magnets by mistake. |
| C．Sufficient chewing hard food. | D．Swallowing metals accidentally. |
| A．To describe the historical practice of putting magnets in cows. |
| B．To deny the adoption of cow magnets to enhance cattle health. |
| C．To discuss the influence of a mild magnetic field on milk quality. |
| D．To explain the reason for using magnets to prevent hardware disease. |
| A．Exploring more potential benefits of cow magnets. |
| B．Investigating the broader applications of magnets. |
| C．Discussing the alternative methods of caring for cows. |
| D．Evaluating the long-term effects of magnets on animals. |
【推荐3】The Earth set unofficial record high temperatures last week. Scientists said they were a clear sign of how pollutants released by humans are warming the environment. “Heat sets the pace of our climate in so many ways... it’s never just the heat,” said Kim Cobb. a climate scientist at Brown University.
Ocean warming, wildfire smoke and early arrived EI Nino that much of North America experienced this summer are other signs of climate troubles. Other recent natural events also show that climate change has entered new territory.
Most of the planet is covered by oceans, which have taken in 90 percent of the recent warming caused by planet-warming gases. In April, worldwide ocean temperature rose to 21, 1°C, which scientists believe was caused by a combination of planet-warming gases and the early EI Nino formation. EI Nino is a period of warning Pacific Ocean waters. Newly published data documented exceptionally warm ocean temperatures in the North Atlantic and also extreme sea heat waves near Ireland, Britain, and in the Baltic Sea.
High levels of wildfire smoke were more common on the US West Coast recently. Several rounds of smoke from wildfires in northern Canada brought dangerous air quality levels to eastern North America. Scientists say that climate change will make wildfires and smoke more intense and that the East Coast will see more of it.
The current EI Nino formed a month or two earlier than usual. It replaced La Nina that, with its cooling of Pacific waters, kept worldwide temperatures down. That means that it will have more time than usual to strengthen. It is predicted that there is a 98 percent chance that at least one of the next five years will be the warmest on record. One of these years would beat temperatures from 2016 when an exceptionally strong EI Nino was present.
1. What did Kim Cobb want to say in the first paragraph?| A．Cold wave might arrive soon. | B．The heat may come to an end. |
| C．The Earth would suffer more. | D．It’s easy to forecast the weather. |
| A．Ireland. | B．Britain. | C．The South Atlantic. | D．The US West Coast. |
| A．More earthquakes. | B．Fewer accidents. | C．Record heat. | D．Extreme cold. |
| A．Weather patterns. | B．Climate troubles. | C．Polluted waters. | D．Green practices. |
