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[阅读小分队] 【Native Speaker 每日训练计划】No.2853【科技】

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发表于 2020-7-28 19:48:28 | 显示全部楼层 |阅读模式
内容:Chopin Hong 编辑:Carrie Qin
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Part I: Speaker

Old Art Offers Agriculture Info
By Susanne Bard on July 24, 2020

Art museums are filled with centuries-old paintings with details of plants that today give us clues about evolution and breeding practices.

Source: Scientific American
https://www.scientificamerican.com/podcast/episode/old-art-offers-agriculture-info/

[Rephrase 1, 02:59

Part II: Speed


The Perseverance rover caps off a month of Mars launches
Three spacecraft from three countries are now on their way to the Red Planet
By Lisa Grossman and Maria Temming on July 30, 2020

[Time 2]
NASA’s Perseverance rover took off at 7:50 a.m. EDT on July 30 from Cape Canaveral, Fla., and is now on its way to Mars with a suite of instruments designed to search for ancient life. The launch is the third this month of spacecraft en route to the Red Planet.

This is the 22nd spacecraft NASA has aimed at Mars (16 of those missions were successful). But Perseverance will be the first mission to cache rock samples from the Red Planet for a future mission to bring back to Earth.

It will also be the first NASA mission in more than 40 years to directly search for life on Mars. The rover will land in a region called Jezero crater (SN: 7/28/20). That crater was once an ancient lake bed, and scientists think its rocks and sediments could preserve signs of life, if life was ever there (SN: 7/29/20). The spacecraft will take video and audio recordings of its own landing as it touches down — another first for a NASA Mars mission.

Mars launches tend to come in clumps thanks to Mars’ and Earth’s orbits. The planets line up on the same side of the sun every two years, so scientists have narrow windows to launch for the most efficient trip. All three of this year’s missions will arrive in February 2021.

[260 words]


[Time3]

The other missions launched in July represent firsts for their respective countries. The United Arab Emirates’ first interplanetary mission, which carries an orbiter called the Hope Probe, launched from Japan on July 19. Hope will measure Mars’ weather, from daily temperature changes to the significance of dust in the planet’s atmosphere (SN: 7/14/20).

Next up was China’s first Mars mission, Tianwen-1, which means “questions to heaven” and launched on July 23. China has previously sent spacecraft to orbit and land on the moon (SN: 1/3/19). And it is the first nation to send an orbiter, lander and rover all at once on its first attempt to reach Mars. “No planetary missions have ever been implemented in this way,” mission scientists wrote July 13 in Nature Astronomy. “If successful, it would signify a major technical breakthrough.”

Tianwen-1’s lander and rover will touch down in Utopia Planitia in April 2021. Instruments on the rover and lander will test Mars’ soil composition and magnetic and gravitational fields and will probe Mars’ interior.

Utopia Planitia is the same region where the first long-lived Mars lander, NASA’s Viking 1, touched down in 1976 (SN: 7/20/16). Viking was the first spacecraft to search for life on Mars, but its results were inconclusive. Perhaps with the rush of spacecraft this year, and the plans to bring red rocks home, scientists will finally learn whether Mars ever did — or does — host alien life.

[255 words]

Source: Science News
https://www.sciencenews.org/article/nasa-perseverance-rover-mission-mars-launch


An ancient skull hints crocodiles swam from Africa to the Americas
By Carolyn Wilke
JULY 23, 2020

[Time 4]
A resemblance between a long-lost African crocodile and modern American crocs goes beyond the shared bump on their snouts.  

New analyses of a roughly 7-million-year old skull from the extinct Crocodylus checchiai suggest that crocodiles journeyed from Africa to the Americas millions of years ago, researchers report July 23 in Scientific Reports. Unearthed in the 1930s, the fossil came from what’s now Libya and sat for decades in a museum. With CT scanning, scientists have now mapped the skull’s structure, revealing hidden anatomical features that tie the animal closely to the four species of American crocodiles alive today.

“It really looks like an American true crocodile, but it comes from Africa,” says Massimo Delfino, a paleoherpetologist at the University of Turin in Italy.

Genetic analyses had already linked the Nile crocodile with its American kin. Though scientists suspected that crocs long ago colonized one of the locales before journeying to the other, the fossil record hadn’t painted a clear picture of which came first.

This C. checchiai specimen predates the earliest known crocodile in the Americas (from roughly 5 million years ago) by about 2 million years. The skull’s structural features place C. checchiai at the base of the American crocs’ branch of the crocodile family tree. But the animal was also a close relative of the Nile crocodile, the researchers found. As a result, the newly described fossil “fills a gap between the Nile crocodile in Africa and the four extant American species,” Delfino says.

The continents would have been in roughly the same place as now when C. checchiai or a close relative may have been on the move. So the new finding suggests that a group of crocs, or at least one pregnant female, may have made a transatlantic journey from Africa to the Americas, Delfino says. “It’s not so surprising,” he says, given today’s crocodilians’ ability to survive saltwater and travel hundreds of kilometers when helped by ocean currents.
[323 words]

Source: Science News
https://www.sciencenews.org/article/ancient-skull-crocodiles-swam-africa-americas



Ancient DNA suggests Vikings may have been plagued by smallpox
By Erin Garcia de Jesus
JULY 24, 2020

[Time 5]

Some Vikings may have died from now-extinct strains of one of humankind’s deadliest pathogens: smallpox.

Researchers collected DNA from viruses in the remains of northern Europeans living during the Viking Age, some of whom were likely Vikings themselves, and found that they were infected with extinct but related versions of the variola virus that causes smallpox, the team reports in the July 24 Science. The new finding pushes back the proven record of smallpox infecting people by almost 1,000 years, to the year 603.

Researchers had previously discovered ancient traces of variola virus DNA in a mummy from the mid-1600s, which put the common origin of modern strains in the 16th or 17th century (SN: 12/8/16).

It is still uncertain when the virus that causes smallpox first began to infect people. The disease is estimated to have killed as many as 500 million people and is the only human pathogen to have been eradicated globally.

Written records from more than 3,000 years ago have documented smallpox-like symptoms, and scientists have identified possible smallpox skin lesions on mummified remains. But it’s difficult to prove that the smallpox virus was the cause.

“This is really exciting work,” says Ana Duggan, an evolutionary geneticist at McMaster University in Hamilton, Canada, who was not involved in the study. “Our understanding of this historical and devastating disease just got a lot wider. We are uncovering [variola virus] diversity that was unknown and unappreciated until right now.”
[241 words]

[Time 6]
Martin Sikora, a computational biologist at the University of Copenhagen, and his colleagues isolated viral DNA from the teeth and bones of 1,867 humans who lived approximately 31,000 to 150 years ago. Of those people, 13 had remnants from the variola virus. Eleven remains belonged to people — including some thought to be Vikings — who had lived in northern Europe, western Russia and the United Kingdom during the Viking Age more than 1,000 years ago. Two others lived in western Russia during the 19th century and were infected with variola virus strains closely related to modern versions.

The team reconstructed nearly complete genetic blueprints of four of the 11 ancient viruses, which reveal that the Viking-era strains belong to a now-extinct group of variola viruses. During that period, smallpox may have been widespread throughout Europe and could have caused serious disease, Sikora says. It’s also possible that if Vikings were infected, they may have spread the disease as they traveled.   

Though the ancient variola viruses are now gone, remnants of their DNA help uncover humans’ extensive relationships with pathogens. “These kinds of pandemics have been part of our history,” Sikora says. “What we see today is only the tip of the iceberg of what was around.”   
[205 words]

Source: Science News
https://www.sciencenews.org/article/smallpox-virus-ancient-dna-teeth-vikings-europeans


Part III: Obstacle



How Dinosaurs Raised Their Young
By Riley Black            |    SMITHSONIANMAG.COM    |    July 24, 2020

[Paraphrase 7]
For more than a century, paleontologists have been confident that all dinosaurs reproduced by laying eggs. After all, no dinosaur gave birth to live young (nor do their modern bird descendants), and nesting sites found from Montana to Mongolia indicate that prehistoric dinosaurs laid clutches of sturdy eggs. Slowly, though, new research has begun to change that picture of dino reproduction.

Up until now, paleontologists thought that all dinosaurs laid hard-shelled eggs. A recent study by University of Calgary paleontologist Darla Zelenitsky and colleagues found that some dinosaurs, like the 73 million-year-old horned dinosaur Protoceratops and the 215 million-year-old, long-necked dinosaur Mussaurus, laid soft-shelled eggs similar to the leathery eggs of some modern reptiles. By mapping out these findings onto the dinosaur family tree, the paper proposes the unexpected idea that all dinosaurs originally initially laid soft-shelled eggs. Over time, at least three different lineages independently evolved hard-shelled eggs.

This research could help to explain why dinosaur eggs are harder to find than many paleontologists would expect because softer eggs would be less likely to fossilize. And working out which dinosaurs laid which types of eggs is important for answering big questions about dinosaur parental care. That’s because no typical dinosaur nest exists. Some species laid lots of round, hard eggs in a pile. Others laid eggs two-by-two and arranged them carefully. Some eggs are spheres. Some are cone-shaped. And as is the case with modern birds, different egg types relate to the ways adult dinosaurs behaved.

“Even among only the hard eggs of dinosaurs, there are considerable differences in the architecture of the eggshell,” says University of Calgary paleontologist Darla Zelenitsky. “Such varied eggshell structure indicates vastly different nest styles, incubation methods, and times between egg-laying and hatching.”

A picture of dinosaur parenting
One matter of debate is whether dinosaur parents stuck around and guard their eggs, or, like today’s sea turtles, laid them and then left the offspring to fend for themselves. The answer seems to vary by species.

For example, consider the parrot-like dinosaurs called oviraptorids. Paleontologists have found the gorgeous skeletons preserved in a position where they seem to be sitting over nests of eggs. “It’s tempting to call this brooding, like living birds,” says San Diego Natural History Museum paleontologist Ashley Poust, “but we’re still unsure if that was part of their behavior.” Still, the details would indicate that the dinosaurs constructed their nests with care. Scientists know from previous finds that oviraptorids laid two eggs at a time in a clutch of 30 or more. “This means that the mother would have to stay with or at least return to the nest, lay her pair of eggs, arrange them carefully in the circle, and bury them appropriately every day for two weeks to a month,” Poust says.

Those eggs would have taken months to hatch. While experts are still searching for definitive evidence, parent dinosaurs may have sat with these nests until the hatchling babies pushed their way out of the shells. Also, Zelenitsky notes, researchers have found a large number of oviraptorosaur nests with adult dinosaur skeletons nearby. “These dinosaurs were completely obsessed with their eggs,” she says.

Oviraptorosaurs were not alone. The shovel-beaked dinosaur Maiasaura, which means “good mother lizard,” got its name in part from Marion Brandvold’s discovery of a nest containing baby dinosaurs too developed to be newborns. In the excavations and analysis that followed, Maiasaura became one of the earliest and best examples of dinosaurs watching over their offspring for an extended period after hatching.

Yet not all dinosaurs were doting parents. For example, the soft eggs that Protoceratops and Mussaurus would have laid, according to the new study, had to be covered so they wouldn’t dry out but were too thin to support the weight of a parent. The dinosaurs that laid soft-shelled eggs would’ve made nests to cover their hatchlings-to-be, but probably didn’t do anything more than watch over the nest area.

The biggest dinosaurs might have done little to look after the next generation. “We have shown parental care in distantly-related dinosaurs,” Poust says, “but for some groups, like sauropods, we don’t have evidence of post-laying care.” Sauropods include the long-necked giants like Apatosaurus and Brachiosaurus. Paleontologists have found their expansive nesting grounds, including some sites where dinosaurs laid eggs in areas that were warm with geothermal activity, perhaps to incubate the offspring. But researchers have no evidence that the parents stuck around.

“Long-necked dinosaurs buried their eggs carefully,” Poust says, “but like turtles, the evidence points to little further care—a strategy of lay ‘em and leave ‘em.”

This image doesn’t quite evoke the tender nurturing of The Land Before Time. But it makes sense biologically. “If giant dinosaurs were nesting in colonies like seagulls and parents remained there until hatching,” Zelenitsky says, “food resources for the parents would likely dwindle fast.” The daily food requirements of large adult dinosaurs may have prevented them from looming over their nests until hatching day. And this, in turn, might help to answer another thorny question.

Sticking together
At various sites around the world, paleontologists have found bonebeds containing young dinosaurs of the same species. A trio of Triceratops, an array of Alamosaurus, and a squad of Sinornithomimus appear to indicate that young dinosaurs of various species grouped together as they navigated their youth.

Why? More eyes offer a better chance to spot predators, for example. Adolescent dinosaurs forming cross-species social groups makes sense given what we know about how harsh life in the Mesozoic could be. Even among Maiasaura, who received better-than-average parental care, nearly 90 percent of the hatchlings died within the first year. If young dinosaurs could last through those first 365 days, and grow large enough not to be a snack for larger carnivores, they stood a better chance at survival.

Perhaps some dinosaurs employed additional parenting strategies, but researches can’t say because they have yet to find the evidence. In this case, living birds might offer some examples of what to look for. Some birds nests collectively, with multiple mothers laying in one nest, Poust says. Did the likes of Allosaurus do the same? We know, too, that some birds are brood parasites, meaning they leave their eggs in the nest of a different species, counting on other parents to raise their young. It’s not out of the question that some non-avian dinosaurs might have tried the technique first, getting another species to take care of their hungry youngster.
[1076 words]

Source: Smithsonian
https://www.smithsonianmag.com/science-nature/dinosaurs-parents-new-egg-discovery-180975361/

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发表于 2020-7-29 21:22:18 | 显示全部楼层
OB:
9:35
发表于 2020-7-30 14:22:34 | 显示全部楼层
#2853
Speak
Peter brugal iconic 1565 painting “the harvester”, hanging in the Metropolis museum of art in New York city. The work to picks peasons , cutting s of wheats, nearly as tall as they are. The work depicts peasants cutting stalks of wheat nearly as tall as they are.
Now, if you work through. You basically see that Wheat is about meter  knee height. The short status  statures is consequently bleeding of second tall half of 20 century.  
University biologist I D SMET
Select breeding favorite favored genes to reduce height because they came along the genes for increasing yield to feed the growing population. D smet says wheat is just one example historical artwork can allow us to track the transformation of food grabs crops over time. He came teamed up with art historical David F to catalog such artwork from around the world.
“We have made been mainly looking at things can transport spot the changes in color, shapes and size.
F says  Friends since childhood, they are interest in plants in artwork  began with the visit to  hemi of museum see peter grey in  St. Petersburg, Russia, where they started looking art  odd looking watermelon early 17 century painting by F from snaters.
“So if you think of watermelon, you got the truth you cut it through, it should be the dark red inside. But it has been paint that one appeared to be pale and white. Biologist dismet, as soon as assumed the painter has done a poor job. But the art historian F has different idea.
“He said he is one of the best painters ever, if he paint like that, that’s the way it must look like.
Other painting review revealed both red and white watermelon were cultivated for XX during the 17 century. The color determined by the gene that controlled the pigment like a p lycopene(番茄红素).
“there must have been some sort of mutation(突变), preventing accumulation of that color. Now with all the genetic knowledge from various plant pieces, that we have we can look in more detail how something go about.
For example the smats says carrot, first started to be painted in orange, only in the 16 century. Thanks to selective breeding beta-carotene( Beta 胡萝卜素) pigment.  Until the 18 century, European strawberry appears tiny in the paintings. They were growing in size process with the advent of cross-breeding, with north American varieties.
The research in the journal trans and plant science. Ultimately, the team hopes to create an online research database of those historical plant artworks. They see the contribution of art enthusiasts around the world be a social media hashtag are generics. But the they caution, the source of painting needs to be realistic  
“if you are going to use, for example, Picasso, to try to understand how a pear looked in the early 20 century, you might be misled.“
Indeed, such an attempt could be fruitless.  
发表于 2020-7-30 15:22:38 | 显示全部楼层
T2 2'13''
T3 2'05''
T4 2'09''
T5 1'26''
T6 1'03''
T7 5'42''
发表于 2020-8-1 17:35:17 | 显示全部楼层
t2:1'19''  :The Perseverance rover caps off a month of Mars launches
t3:1'20''
t4:1'38''  An ancient skull hints crocodiles swam from Africa to the Americas
t5:1'07''Ancient DNA suggests Vikings may have been plagued by smallpox(天花)
t6:45''
发表于 2020-8-2 13:13:11 发自手机 Web 版 | 显示全部楼层
T2   1'47
T3   1'53
T4   2' 06
发表于 2020-8-3 01:56:22 | 显示全部楼层
ob 10’
发表于 2020-8-3 13:04:02 | 显示全部楼层
OB 8'30

Different types of eggs of dinosaurs can indicate different styles of parental caring. Some dinosaurs may guard their eggs by covering them with soil, while some of them do nothing rather than watch over the area.
发表于 5 天前 | 显示全部楼层
#2853
Speak
Iconic, the harvester. Keen height. To track the food corps overtime. Watermelon, F. pale and while.  
Online research platform. Realistic. Mislead. Fruitless.

Time2 [260 words] 1:29
Another mission fight to Mars was launched in July 30th with the direct object to search live in Mars. It will land in feb 2021 at an crater where it was an ancient lake and will gather the inform for lives if it ever had.
Time3 [255 words]  2:30
3 mission have been launched in June 2020. Besides the one from the US, another one from united arab’s interplanetary mission which carries an orbiter called hope probe, launched from japan.
China has its tianwen-1 with orbit, lander and rover all at once on its first attempt to reach Mars. If successful, it would signify a major technical breakthrough.
Time4 [323 words] 2:53
Crocodile journeyed from Africa to Americas millions years ago.
It is not so surprising, crocodilian’s ability to survive saltwater and travel hundreds of kilometers when helped by ocean currents
Time5 [241 words] 2:24
New research found the Vikings may dead because of smallpox and push back the proven record of virus infecting people about 1000 years.
Time6 [205 words] 2:11
Part III: Obstacle [1076 words] 10:00

发表于 5 天前 | 显示全部楼层
非常感谢楼主的分享!
1’35
A NASA’s launch to Mars with its missions.
1’15
Another mission of NASA’s launch. Introduction of China’s Tianwen-1.
2’55
An ancient crocodile skull from Africa is related to living American crocodile species. It may suggest that the African crocodile swam to America.
1’35
A finding of smallpox that may lead to death of Vikings. It is not sure when the smallpox began to infect human beings, but scientists are exciting that it widen their research.
1’03
Although the virus were gone, scientists are able to use the DNA extracted from teeth and bones to identify strains of these virus.
OB 10’16
Dinosaurs were considered laying off hard-shell eggs, but new research shows they laid off soft-shell eggs initially and evolved to lay off hard-shell eggs. Different species show different parental styles. Some lay eggs and hatch them until new born, but some lay eggs and leave. They get together to offer better chance to spot predators.
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