【推荐1】By the time most of the world discovered the kipunji monkey, it was already seriously endangered. These rare animals live in Tanzania and is not closely related to any other known monkeys. Thanks to smart protection efforts, their population is accumulating.

Kipunji monkeys live in groups and spend most of their time in trees. Local hunters knew about them, but researchers first identified the species in the early 2000s. A 2007survey found 1, 117 of the animals alive. Experts from organizations such as the Wildlife Conservation Society (WCS) stepped in to try to save the species.

One method of protecting kipunji monkeys was to reduce conflict between the monkeys and humans. Kipunji often come out of the forest to steal bananas, and carrots from farms, leading farmers to set traps that can kill the monkeys. So WCS workers put unpleasant things such as chili oil (辣椒油) on the leaves of the crops to keep the monkeys away. Farmers have also started growing crops like potatoes, which the monkeys are less interested in eating.

To discourage people from cutting down trees in the kipunji’s habitats (栖息地), the WCS has established other sources of wood. Kipunji habitats have been turned into protected parks and reserves.

So far, their efforts have been successful. A 2022 study found that the area in which the monkeys live has increased in size by nearly 20%, and their population has risen to 1, 966 animals. If the efforts continue, the population of kipunji monkey could double in 25 years. “It’s not perfect,” former WCS director Tim Davenport said. “But it’s in a considerably better place than it used to be.”

【推荐2】Crows (乌鸦) are incredibly smart. Researchers have already discovered that these dark birds possess primary consciousness- the ability possessed by humans and some primates to integrate memories to think in terms of past and present. A recent study expands the wealth of knowledge on these clever creatures. In the study, researchers discovered that crows can comprehend the concept of zero.

The concept of "none", or the absence of any quantity, which emerged earlier than the concept of zero, differs from using zero as a distinct “quantity", in and of itself. Zero is actually a rather recent mathematical invention. This makes the crow's newly discovered ability all the more impressive.

Going into their experiment,' the researchers at the University of Fubiggen in Germany knew that crows have certain neurons(神经元) which light up when they see certain quantities displayed. One dot fires a certain neuron, two another, three another, and four yet another, It was therefore already known that crows could distinguish these quantities from one another.

To test whether crows could comprehend zero as a numerical value, the researchers showed crows two displays of dots (点), each display containing between zero and four. The crows were trained to indicate if the two displays showed the same value. While they did this, researchers observed how their brains responded. When the crows saw "zero" dots, their brains tired a new neuron recognizing new “quantity."

Sometimes the birds made mistakes, identifying two displays as representing the same quantity. “Where zero was concerned, the bird more often confused it for displays with one dot than those with two or more," said co-author Andreas Nieder. “This effect would only be expected if crows can understand the empty set as the smallest numerical value on the number line."

【推荐3】Livestock(牲畜)cloning is the practice of cloning sheep, cattle and other livestock species as a way to improve efficiency. The basic idea behind livestock cloning is to clone animals that have certain qualities, such as cows that produce more milk or meat.     1    

However, this practice is very controversial, and livestock farmers have been hesitant to adopt it fully because of public opposition and certain inefficiencies.

In technical terms, livestock are cloned by taking cells from one animal and using them to fertilize(使受精)eggs. Scientists take the fertilized eggs and put them in female animals.     2       Many animals are born with abnormal shapes. Scientists are looking for ways to improve the process and make it less expensive to adopt on a wider scale.

    3     For example, if farmers were able to take only their very best animals and recreate them many times, they could potentially be more productive.

There are also some potential problems with cloned livestock.     4     For example, when a disease hits, there are usually individuals that cannot be harmed by the disease or are more resistant, and they will generally survive. If all the animals were genetically(在基因方面)similar, this sort of disease could totally destroy an entire generation of livestock.

In addition to concerns about genetic diversity, there are other concerns about cloning.     5     There are also some people who worry that livestock cloning research may be a gateway to introducing human cloning, which is widely disapproved of.

【推荐1】The 19th century landscape paintings in the museum looked awfully familiar to climate physicist Albright. Artist Turner’s signature way of covering his views in fog and smoke reminded Albright of her own research — tracking air pollution. After all, Turner —a forerunner of the impressionist movement — was painting as Britain’s industrial revolution gathered steam and smoke.

To find out how much realism there is in impressionism, Albright teamed up with Harvard University climatologist Peter Huybers. Their analysis of nearly 130 paintings by Turner, Paris-based impressionist Claude Monet and several others tells a tale of two modernizing cities.

Low contrast and whiter colors are typical of the impressionist style. They are also typical of air pollution. Tiny aerosols (气溶胶) can absorb or distribute light. That makes the bright parts of objects appear less bright while also shifting the entire scene’s color toward white.

Albright and Huybers distinguished art from aerosols by first using a mathematical model to analyze the contrast and color of 60 paintings that Turner made between 1796 and 1850 as well as 38 Monet works from 1864 to 1901. They then compared the findings to sulfur dioxide emissions (二氧化硫排放量) over the century and estimated from the trend in the annual amount of coal sold and burned in London and Paris. When sulfur dioxide reacted with molecules (分子) in the atmosphere, aerosols formed.

As sulfur dioxide emissions increased over time, the amount of contrast in both Turner’s and Monet’s paintings decreased. However, paintings of Paris that Monet made from 1864 to 1872 have much higher contrast than Turner’s last paintings of London made two decades earlier. They owed the difference to the much slower start of the industrial revolution in France. Paris’ air pollution level around 1870 was about what London’s was when Turner started painting in the early 1800s. It confirmed that the similar progress in their painting styles couldn’t be coincidence, but was guided by air pollution, the pair concluded.

【推荐2】A new study led by researchers at the Yale School of Public Health finds air pollution may negatively impact standardized test scores. Using data from the North Carolina Education Research Data Center, the researchers tracked 2.8 million public school students in North Carolina from 2001 to 2018 and measured their exposure to PM2.5 found in polluted air. While previous research has shown negative effects on academic performance, it has relied on relatively small or less representative samples. “The biggest strength of this study is that we tracked every student in North Carolina in those years, for the whole time period that they were in the public schools,” said Emma Zang, coauthor of the study.

The study also finds that test scores of ethnic minorities and girls are disproportionately (不成比例地) impacted by PM2.5 levels. “Females and ethnic minorities face sexism and racism,” said Zang. “There are a lot of policies that are not friendly towards them. So, when they’re exposed to the same level of air pollution, they don’t have the resources to lessen the negative influences.” More privileged populations, however, might have more resources that allow them to live in a better environment, such as in houses with air purifiers.

“The level of PM2.5 pollution in the US is relatively low, but students living in areas below the current air quality standard of annual PM2.5 concentration are still negatively impacted by air pollution when it comes to their test scores,” said Zang. “We should aim to strengthen the annual PM2.5 standard to better protect our children.”

Air pollution is known to contribute to disease and death, and it also negatively affects students’ academic performance even at low levels of pollution. The subsequent studies, the researchers said, would involve looking at whether the findings hold true in different areas, and also the reasons behind the ethnic and sexual differences.