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内容：Jones Cao 编辑：Jones Cao
Wechat ID: NativeStudy / Weibo: http://weibo.com/u/3476904471
Part I: Speaker Mom's Genes Make Some Giraffes Hard to Spot By Christopher Intagliata on October 10, 2018 [Rephrase 1, 01:57]
Source: Scientific American https://www.scientificamerican.com/podcast/episode/moms-genes-make-some-giraffes-hard-to-spot/
Part II: Speed Nearly 2 million U.S. adult nonsmokers vape BY AIMEE CUNNINGHAM 1:20PM, OCTOBER 9, 2018 [Time 2] Nearly 2 million U.S. adults who have never consistently smoked traditional cigarettes use e-cigarettes, according to results from a national survey. Of these sole e-cig users, about 60 percent are young adults, aged 18 to 24, researchers report online October 9 in Annals of Internal Medicine.
E-cigarette companies have marketed the devices — which heat and vaporize liquids that typically contain nicotine — as a way to help adults quit smoking. But some public health officials worry that e-cigarettes could become a means to nicotine addiction, rather than an end.
This concern is especially true for adolescents and young adults, whose developing brains are vulnerable to nicotine exposure, which can cause addiction and other harms (SN Online: 8/19/15). E-cigarettes also can pose a variety of other health risks (SN: 3/5/16, p. 16).
Researchers analyzed 2016 data from the U.S. Centers for Disease Control and Prevention’s Behavioral Risk Factor Surveillance System. Among 261,541 nonsmokers, defined as having less than 100 cigarettes in a lifetime, 1.4 percent reported vaping. That corresponds to about 1.9 million sole e-cigarette users when extrapolated to the U.S. adult population in 2016. About 1.2 million of those users were young adults.
The work “highlights the potential need to regulate sales and marketing of e-cigarettes to protect vulnerable populations, including young persons who have never smoked combustible cigarettes,” the researchers say. [221 words] Source: Science News https://www.sciencenews.org/article/nearly-2-million-us-adult-nonsmokers-vape?tgt=nr
The economics of climate change and tech innovation win U.S. pair a Nobel BY BRUCE BOWER 12:09PM, OCTOBER 8, 2018
[Time 3] Two U.S. economists, William Nordhaus and Paul Romer, have received the 2018 Nobel Memorial Prize in Economic Sciences for their efforts to untangle the economics of climate change and technological innovations.
Nordhaus and Romer “significantly broadened the scope of economic analysis by constructing models that explain how the market economy interacts with nature and knowledge,” the Royal Swedish Academy of Sciences said in a statement announcing the awards on October 8.
Nordhaus, of Yale University, developed two computer simulations that weigh the costs and benefits of taking various steps to slow global warming. He has argued for taxes on the carbon content of fuels as an effective way to get businesses to reduce greenhouse gas emissions. The Environmental Protection Agency has used Nordhaus’ work, among others, to estimate the economic impacts of climate change.
The announcement of Nordhaus’ award came just hours after a United Nations panel on climate change released a report predicting grim future effects of climate change and calling for more vigorous action by world governments to limit warming to 1.5 degrees Celsius over preindustrial times (SN Online: 10/7/18). The new report cites Nordhaus’ work.
Romer, of New York University, expanded economic theory by arguing that government policies, such as funding for research and development, can stimulate technological advances. The presence or absence of such policies helps to explain national differences in wealth and economic growth, in Romer’s view.
Romer’s ideas about policy making and technological innovation, first published in 1990, inspired a school of research that examines how business regulations and policies lead to new ideas and economic growth.
The pair will split the 9-million-Swedish-kronor (about $1 million) award. [273 words]
Source: Science News https://www.sciencenews.org/article/economics-climate-change-and-tech-innovation-win-us-pair-nobel?tgt=nr
If the past is a guide, Hubble’s new trouble won’t doom the space telescope BY LISA GROSSMAN 3:03PM, OCTOBER 10, 2018
[Time 4] Hubble’s in trouble again.
The 28-year-old space telescope, in orbit around the Earth, put itself to sleep on October 5 because of an undiagnosed problem with one of its steering wheels. But once more, astronomers are optimistic about Hubble’s chances of recovery. After all, it’s just the latest nail-biting moment in the history of a telescope that has defied all life-expectancy predictions.
There is one major difference this time. Hubble was designed to be repaired by astronauts on the space shuttle. Each time the telescope broke previously, a shuttle mission fixed it. “That we can’t do anymore, because there ain’t no shuttle,” says astronomer Helmut Jenkner of the Space Telescope Science Institute in Baltimore, who is Hubble’s deputy mission head.
The most recent problem started when one of the three gyroscopes that control where the telescope points failed. That wasn’t surprising, says Hubble senior project scientist Jennifer Wiseman of NASA’s Goddard Space Flight Center in Greenbelt, Md. That particular gyroscope had been glitching for about a year. But when the team turned on a backup gyroscope, it didn’t function properly either.
Astronomers are working to figure out what went wrong and how to fix it from the ground. The mood is upbeat, Wiseman says. But even if the gyroscope doesn’t come back online, there are ways to point Hubble and continue observing with as few as one gyroscope.
“This is not a catastrophic failure, but it is a sign of mortality,” says astronomer Robert Kirshner of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. Like cataracts, he says, it’s “a sign of aging, but there’s a very good remedy.”
While we wait for news of how Hubble is faring, here’s a look back at some of its previous hiccups and repair missions. [293 words]
[Time 5] 1990: The blurry mirror
On June 27, 1990, three months after the space telescope launched, astronomers discovered an aberration in Hubble’s primary mirror. Its curvature was off by two micrometers, making the images slightly blurry.
The telescope soldiered on, despite being the butt of jokes on late-night TV. It observed a supernova that exploded in 1987 (SN: 2/18/17, p. 20), measured the distance to a satellite galaxy of the Milky Way and took its first look at Jupiter before the space shuttle Endeavour arrived to fix the mirror in December 1993.
1999: The first gyroscope crisis
On November 13, 1999, Hubble was put into safe mode after the fourth of its six gyroscopes failed, leaving it without the three working gyros necessary to point precisely. An already planned preventative maintenance shuttle mission suddenly became more urgent. NASA split the mission into two parts to get to the telescope more quickly. The first part became a rescue mission: Astronauts flew the space shuttle Discovery to Hubble that December to install all new gyroscopes and a new computer. 2004: Final shuttle mission canceled
After the space shuttle Columbia disintegrated while re-entering Earth’s atmosphere in 2003, NASA canceled the planned fifth and final Hubble reservicing mission. “That could really have been the beginning of the end,” Jenkner says.
The team has known for more than a decade that someday Hubble will have to work with fewer than three gyroscopes. To prepare, Hubble’s operations team deliberately shut down one of the telescope’s gyroscopes in 2005, to observe with only two.
“We’ve been thinking about this possibility for many years,” Wiseman says. “This time will come at some point in Hubble’s mission, either now or later.” [282 words]
[Time 6] Shutting down the third gyroscope was expected to extend Hubble’s life by only eight months, until mid-2008. In the meantime, two of the telescope’s scientific instruments — the Space Telescope Imaging Spectrograph and the Advanced Camera for Surveys — stopped working due to power supply failures.
2009: New lease on life Fortunately, NASA restored the final servicing mission, and the space shuttle Atlantis visited Hubble in May 2009 (SN Online: 5/11/09). That mission restored Hubble’s cameras, installed new ones and crucially, left the space telescope with six new gyroscopes, three for immediate use and three backups. The three gyroscopes still in operation (including the backup that is currently malfunctioning) are of a newer type, and are expected to live five times as long as the older ones, which last four to six years.
The team expects Hubble to continue doing science well into the 2020s and to have years of overlap with its successor, the James Webb Space Telescope, due to launch in 2021. “We are always worried,” says Jenkner, who has been working on Hubble since 1983. “At the same time, we are confident that we will be running for quite some time more.” [194 words] Source: Science News https://www.sciencenews.org/article/hubble-new-trouble-probably-wont-doom-space-telescope?tgt=nr
Part III: Obstacle Daily low-dose aspirin is not a panacea for the elderly BY AIMEE CUNNINGHAM 9:30AM, SEPTEMBER 19, 2018 [Paraphrase 7] A daily dose of aspirin? Not a good idea if you’re a healthy elderly adult.
A trio of papers based on a large-scale clinical trial finds that the drug doesn’t help to stave off heart attacks, strokes, dementia or physical disability. In fact, those in their golden years who took a low dose of aspirin daily were more likely to suffer serious internal bleeding than those who took a placebo. The researchers even observed more deaths among those on aspirin, although that result wasn’t statistically significant.
The clinical trial, called ASPREE or Aspirin in Reducing Events in the Elderly, included more than 19,000 adults. About half of those adults were randomly assigned to take 100 milligrams of aspirin per day and the other half a placebo pill for around five years.
The papers, published online in the New England Journal of Medicine on September 16, “once again remind us that aspirin is not a benign drug,” says cardiologist Jeffrey Berger of New York University School of Medicine who was not part of the research.
“There’s a lot of misunderstanding of the original data in support of aspirin,” he says. The notion that everyone in older age should take aspirin to prevent a first heart attack or stroke, Berger says, “is not born out from the evidence to date.” Yet a 2015 study found that nearly half of 2,039 U.S. adults ages 45 to 75 who didn’t report a history of cardiovascular disease were regularly taking aspirin.
Here are a few of the key findings from the new studies, as well as some common points of confusion over medical guidance for taking aspirin. Does aspirin protect against heart attacks?
Yes, if you already have had a heart attack or stroke or have coronary artery disease. “If you’ve had a heart attack, it’s not debatable: Aspirin saves lives,” Berger says. Clinical trials have shown that low-dose aspirin significantly reduces subsequent heart attacks and strokes in those patients, equating to about 10 to 20 fewer of these events per 1,000 people per year. That benefit outweighs the increases seen in occurrences of internal bleeding.
What’s unsettled is whether aspirin can help prevent a first heart attack or stroke in people without cardiovascular disease, and the new work casts additional doubt. Official recommendations are mixed, too. The latest U.S. Preventive Services Task Force guidelines, from 2016, recommend that people aged 50 to 59 who have at least a 10 percent risk of developing cardiovascular disease take up to 100 milligrams of aspirin daily. The organization also finds some evidence that the dose may be slightly beneficial for those 60 to 69 with that same cardiovascular disease risk. But the U.S. Food and Drug Administration does not support using aspirin for preventing a first heart attack or stroke, arguing the evidence lacking.
In the new research, Anne Murray, a geriatrician and medical director of the Berman Center for Outcomes and Clinical Research at Hennepin Healthcare in Minneapolis, and her colleagues wanted to study whether aspirin was helpful for preventing cardiovascular disease for even older adults. The researchers’ trial included Australians and some Americans 70 and older, with black and Hispanic American participants aged 65 and older, although most participants were white.
The rates of cardiovascular disease, including heart attacks and stroke, were about the same between the aspirin and placebo groups: 10.7 events per 1,000 people per year on aspirin and 11.3 events per 1,000 people on the placebo. But those on aspirin were significantly more likely to develop a major hemorrhage, or bleeding, in the stomach, intestines or brain, with 8.6 events per 1,000 people compared with 6.2 events per 1,000 people on the placebo.
Why did the researchers also investigate dementia and disability?
“Those are the two things that play the largest role in whether people are able to remain independent” in their later years, Murray says. She and her colleagues thought that the blood-thinning and anti-inflammatory properties of aspirin might decrease the risk of dementia and physical disability by ameliorating small vessel disease, or abnormalities in the brain’s small blood vessels that have been linked to impairments in thinking and movement.
But that hypothesis didn’t pan out. The combined rates of dementia, physical disability and death were nearly the same between the aspirin and placebo groups: 21.5 events versus 21.2 events per 1,000 people per year, respectively.
“There really are no measurable benefits of taking low dose aspirin” for healthy elderly adults, Murray says. “Certainly the benefits don’t outweigh the risk of bleeding.” Doesn’t aspirin reduce the risk of some cancers?
Yes, for colorectal cancer. Aspirin taken long-term, especially for 10 years, reduces the risk of this cancer, according to numerous studies. The U.S. Preventive Services Task Force recommends aspirin for people aged 50 to 59 to prevent colorectal cancer, finding the evidence is strongest for these adults.
Surprisingly, in the new work, “we did find that cancer made up the highest proportion of people who died,” among those in the aspirin group, Murray says. “That was unexpected, and we’re not clear why.” The trial didn’t find that aspirin increased or reduced cancer risk in healthy elderly adults.
The researchers want to study aspirin use in these elderly adults for five more years to see if longer-term use offers any protection against cancer in this age group, and if so, whether it outweighs the higher risk of internal bleeding. [900 words]
Source: Science News https://www.sciencenews.org/article/daily-low-dose-aspirin-not-panacea-elderly
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发表于 2018-10-12 04:43:22
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