Part I：Speaker 【Rephrase】 Article 1 Limit Youth Football Practice Hits for Brain Health Changes in youth football practices cut total hits to the head in half, whereas leaving game situations unaffected. Ingrid Wickelgren reports
Transcript hided
Brain injury is a growing concern in football. But changes during practice could make the game safer for kids by cutting total blows to the head in half. So finds the largest study ever to measure head impacts in youth football. The work is in the Annals of Biomedical Engineering. [Bryan R. Cobb et al., Head Impact Exposure in Youth Football: Elementary School Ages 9–12 Years and the Effect of Practice Structure]
Researchers put accelerometers in the helmets of 50 9- to 12-year-olds on three teams to detect forces on the head. For kids on two teams, practice was far riskier than games: they got more than twice as many whacks to the skull at practice than in games. The more hits, the greater the chance of brain injury.
But the third team got knocked in the noggin only half as often as the others—and the difference was entirely from workouts. That team not only practiced less but their sessions were safer: players followed new Pop Warner rules that restrict the number of contact drills and outlaw the roughest ones.
During actual games, however, contact was the same for all players—which shows that protecting kids in practice doesn’t change the product on the field. It can stay as brutal as we like. [Dialog, 1:15]
Part II：Speed
【Time 1】
Article 2 Forget Plumage, Birds Sniff Out Good Mates
Birds are known for their eyesight, not their sense of smell. But the odors they emit may play a key role in helping them land mates, according to a new study. Most bird odors originate from the oils in the preen gland. Birds use their beak to rub preen oil over their feathers while grooming. To study the effects of different odors on mate choice, researchers collected preen-oil samples from 34 dark-eyed juncos, a common North American sparrow. They then put together a profile of odor compounds more typically found in males and those more typically found in females. Researchers assigned a score to birds based on the proportion of compounds in the preen oil. The higher the score, the greater abundance of malelike odor compounds. The high-scoring males produced the greater number of offspring (between six to seven fledglings) compared to the low-scoring males who had no surviving offspring. The study, to be published in the October issue of Animal Behaviour, also found that bird odor was a more reliable predictor of reproductive success than a male’s size or his plumage. Researchers also looked at social reproductive success, or the male's ability to raise offspring of their own as well as those sired by other males. Good “father” birds tended to have a more malelike odor.
字数[217] Source: http://news.sciencemag.org/plants-animals/2013/08/scienceshot-forget-plumage-birds-sniff-out-good-mates
【Time 2】 Article 3 The Pesticide Paradox
Pesticides—a vast range of chemicals that kill insects, weeds, fungi, and other organisms humans would rather do without—bring some great benefits to society. They have made it possible to feed a growing human population, and they protect millions from malaria and other insect-borne diseases. They also support important economic sectors such as the cotton and flower industries and help make our lives easier and more enjoyable; for instance, by reducing mosquito, ant, and cockroach populations. Yet the potentially serious threats they pose to human health and the environment have led to a series of bans on the most dangerous chemicals and to calls to go much further. This spring, the European Union took a new step by issuing a partial ban on three neonicotinoids, a widely used group of insecticides suspected of harming bees, butterflies, and other nontarget species.
Although science is guiding some policy changes, there is still room for major improvement when it comes to pesticides, by more carefully tracking their effects, using them more judiciously, reducing their negative impacts, and finding alternatives. Scientists are making strides in precisely understanding the effects of the chemicals now in our arsenal, including the myriad ways in which they are broken down in the environment and the harm they cause to wildlife. Meanwhile, cohort studies in the United States are beginning to map out their troubling effects on the young developing brain.
Reducing the negative fallout from pesticides is possible in many ways. Australia's wheat farmers are tackling one of the worst weed problems in the world (a crisis that, ironically, partly arose from overreliance on herbicides) by using a more diverse set of tools. Pesticide overuse is a big problem in Asia, too; although cheap, they hurt the farmer's bottom line in the long run. Vietnam has developed a pioneering program that is paying dividends to farmers who spray less. Also in Asia, scientists are tackling one of the biggest problems: More than 300,000 people are believed to commit suicide every year by swallowing pesticides.
字数[337] Source: http://www.sciencemag.org/content/341/6147/728
【Time 3】 Article 4 Predictors of suicidal behaviour found in blood Changes in gene expression can indicate heightened risk for self-harm.
People who are intent on taking their own life may not seek counsel or discuss their thoughts with others. Having some ways of predicting the rise of suicidal thoughts could help save at least some of the 1 million people worldwide who die that way every year.
“It’s a preventable tragedy,” says Alexander Niculescu, a psychiatrist at Indiana University in Indianapolis who is looking for biological signs of suicide risk.
Because of the brain's complexity and inaccessibility, the search for predictors of suicide risk has instead focused on molecular signs, or biomarkers. These biomarkers help to indicate which people are at even higher risk. Niculescu and his colleagues have found six such biomarkers in blood that they say can identify people at risk of committing suicide. Their work is published in Molecular Psychiatry.
The study by Niculescu and his colleagues had four distinct phases. First, they identified nine men with bipolar disorder from a longitudinal cohort study at Indiana University who, between visits to the lab, had switched from having no suicidal thoughts to scoring highly on a suicide-risk scale. They looked for changes in gene expression in men’s blood cells, and identified candidate biomarkers. These biomarkers were then checked against previous work on genes related to mental illness and suicide to identify 41 most likely to be involved. “It works like a Google search ranking,” says Niculescu. “Those that had the most independent lines of evidence got the highest rank.”
Next, the researchers checked their results against blood samples taken by the coroner from nine men who had committed suicide. This enabled them to narrow their list of candidate biomarkers from 41 to 13. After subjecting the biomarkers to more rigorous statistical tests, Niculescu's team was left with six which they was reasonably confident were indicative of suicide risk.
字数[301]
【Time 4】
To check whether these biomarkers could predict hospitalizations related to suicide or suicide attempts, the researchers analysed gene-expression data from 42 men with bipolar disorder and 46 men with schizophrenia, and found that correlations with four of their biomarkers, especially in the bipolar group. This indicates that the active genes are not just ‘state markers’ of immediate risk but ‘trait markers’ that can indicate long-term risk. When the biomarkers were combined with clinical measures of mood and mental state, the accuracy with which researchers could predict hospitalizations jumped from 65% to more than 80%.
The strongest predictor was a biomarker encoded by a gene called SAT1. “It was head and shoulders above the rest,” says Niculescu. The work “opens a window into the biology of what’s happening,” he says.
Ghanshyam Pandey, a psychiatrist at the University of Illinois at Chicago, says that Niculescu’s work is an important step in the search for psychiatric biomarkers, but the small sample size means the results will have to be validated in much larger groups and tested for specificity and sensitivity before the results could be used clinically. “That’s a big challenge,” Pandey says.
Niculescu says that this type of work is usually done with much larger sample sizes but that he and his colleagues used rigorous, multi-step methods to weed out false positives. The next step, he says, is to look at the levels of these biomarkers in the general population and in other at-risk populations, such as those with depression or suffering from stress or bereavement. “Suicide is not just related to mental illness,” he says. “It’s a very complex behaviour.”
字数[269] Source: http://www.nature.com/news/predictors-of-suicidal-behaviour-found-in-blood-1.13570
【Time 5】 Article 5 NASA gives up on fixing Kepler
NASA’s planet-hunting Kepler space telescope, hobbled by the breakdown of two crucial parts, is beyond repair, officials announced in a teleconference August 15.
In May the Kepler team reported that two of the four reaction wheels used to turn the spacecraft toward its stellar targets had failed, leaving the telescope incapable of detecting the small dips in starlight that signify the existence of distant planets (SN Online: 5/15/13; SN: 6/15/13, p. 10). Last month engineers forced the faulty wheels back into action one at a time and found high friction levels when each of them spun. Exceedingly high resistance to spin is a death sentence for telescopes that rely on reaction wheels.
Still, last week engineers tried using Wheel 2, the more promising of the two troubled wheels, plus the two functional ones, to direct the telescope. Kepler worked for about six hours before the wheel encountered so much friction that the telescope automatically turned itself off. “The wheels are sufficiently damaged that they cannot sustain spacecraft pointing control for any extended amount of time,” said Charles Sobeck, Kepler’s deputy project manager.
Kepler scientists are now exploring what the telescope can accomplish with just two reaction wheels, and in the fall NASA will determine whether that justifies any of the roughly $18 million allocated to the mission this year. It will be a tough sell: Kepler’s precision focus is what made it an unprecedented astronomical asset.
字数[236] Source: http://www.sciencenews.org/view/access/id/352469/description/KEPLER_BEYOND_REPAIR
Part III： Obstacle
【Time 6】
Article 6
Crittercams and Crowdsourcing to Solve Mystery of Hawaiian Monk Seals? Scientists hope schoolkids can help reveal how endangered seals spend their days.
In a move that has baffled scientists, one of the world's rarest marine mammals—the Hawaiian monk seal—is setting up shop on the populated islands of Hawaii.
With a population that hovers around 1,100, most of the world's silvery, seven-foot-long (two-meter-long) monk seals live on the uninhabited northwest Hawaiian Islands, in the Papahānaumokuākea Marine National Monument.
They've lived there for as long as Western history records, said Charles Littnan, lead scientist with the U.S. National Oceanic and Atmospheric Administration's Hawaiian monk seal research program in Honolulu.
But their population has been in decline for the past 30 to 40 years. Scientists are still trying to figure out why.
In the late 1990s, however, this endangered mammal saw a glimmer of hope, with a noticeable uptick in monk seal numbers on the main Hawaiian Islands like Kauai, Molokai, and Oahu. Together, the islands are home to over one million people.
Today, about 150 to 200 monk seals—roughly ten percent of the total monk seal population—call the main islands home.
"In the main Hawaiian Islands, totally counterintuitively, you have a population of seals—still relatively small—that is growing at about seven percent a year," Littnan said. "All the animals are fat, healthy, and happy."
A New Competitor? But some of the human residents aren't so enthused.
Fishermen who grew up locally, in an environment without monk seals, now feel like they're competing with the animals for the same resources, like octopuses and a fish locals call aholehole. "I fish all my life on the ocean and never saw any seals," said Ray Arezo, a Hawaii resident who fishes to help feed his family.
"They know how to pick the net with their flippers," he said. "They go over, they bite [the fish], and grab it and take it off the net."
Littnan says that he has heard the seals described as "a swarm of locusts moving across the bottom of the ocean" and that they eat 600 pounds (272 kilograms) of fish a day. "The largest a monk seal gets is 600 pounds, and most are considerably smaller," Littnan said. "So that's obviously a physical impossibility."
Tensions between seals and humans have produced local headlines about seal deaths under "suspicious" circumstances, even though it's a state and federal crime to harm or kill the endangered seals.
The headlines provoked Littnan to investigate what monk seals really do while underwater, with help from some Crittercams—small video cameras mounted on animals to study their behavior. "We're not here to sell monk seals to anyone," Littnan said. "We want the truth."
The preliminary results show that some of the community's perceptions of the seals are off. But Littnan knew that getting fishermen and other locals to accept the results of a study from a government scientist would be tough sailing.
Community Inclusion Rather than conducting a scientific study in the usual way—collecting data, analyzing the results, publishing findings—Littnan wanted to involve locals from the get-go.
He hoped that involving the public in the study's planning stages, and getting preliminary data out quickly, would keep frustrations with the seals from boiling over.
"It buys us time," he said. "It hopefully saves a seal or two while we work to [answer] these more difficult questions in terms of what role or what impacts do monk seals really have and what level of fisheries interactions are there?"
In early 2012, researchers held four public meetings on the islands of Molokai, Kauai, and Oahu (map) to get public input on how to design their monk seal study.
Then Littnan and his team worked with locals on ways to analyze the hundreds of hours of video the project would collect, so that residents would be more apt to accept the results.
"There's no way we're going to be able to get every person in the public to sit down and watch 180 hours of Crittercam footage," Littnan said.
But when a Molokai resident suggested that Littnan employ local middle and high school students to analyze the footage for him, he embraced the idea.
Now, researchers take all their footage from video camera deployments—they've made eight successful ones to date—make two copies and send one copy to classes on Molokai. "They get the data before we get to look at it," Littnan said.
The hope is that if someone at a public meeting challenges the team's findings, students from the community can vouch for the footage.
Some of the students get very passionate about the project, Littnan said, and are frustrated that some people don't believe the results they've been getting from the video.
Eye-Opening Results Early analysis from the three- to four-day Crittercam deployments—done in partnership with National Geographic—show monk seals doing a variety of things underwater: eating, swimming, and sleeping.
But to consume 600 pounds (272 kilograms) of fish a day, as Littnan has heard some locals allege, a monk seal would have to eat a pound of fish every 45 seconds. The cameras showed seals would sometimes spend 15 minutes trying to get just one fish.
And footage shows the seals totally ignoring the aholehole fish, the one some locals believed the animals were eating up.
"There's a lot of sleeping," Littnan said. Monk seals will wedge themselves under ledges on the seafloor and doze for 10 to 15 minutes at a time.
One camera caught a monk seal fending off sharks intent on stealing its meal of an octopus.
"We're blowing a lot of these misconceptions out of the water already," Littnan said.
Local Ownership And Littnan's plan for getting people to sit down at the table to start talking appears to be working. A recent public meeting with 170 attendees, from tourists to fishermen, was very friendly. "There was information exchange happening," he said. "People left knowing more."
Taylor Heckman, a recent high school graduate from Oahu, won an essay-writing contest about monk seals and got to accompany Littnan and a team of researchers while they attached Crittercams to the marine mammals on Molokai in February.
"They get to see the community of monk seals in a whole different way than they've ever experienced because [the seals aren't] just lying on a beach asleep or being problematic in fishing spots," said Heckman, describing her fellow students watching the Crittercam videos.
Terry Heckman, Taylor's mother, agrees. "The Crittercams are fun to watch," Terry said. "It's really interesting to see what they're doing, so sharing the video is a good way to get people excited about monk seals."
Littnan is about halfway through the three-year project and plans to deploy at least 15 more cameras on monk seals.
It's still too early to definitively say how the marine mammals spend all their time while they're out to sea, but we have more insights than ever before.
Before, researchers didn't pay much attention to monk seals on the main Hawaiian Islands because there were so few of them, Littnan said.
"And now, it's one of the greatest hopes for the future of the species' existence," he said. "It's absolutely essential that we find a way to balance the needs of the animals and the needs of the people in order to make sure that these animals persist."
字数[1209] Source: http://news.nationalgeographic.com/news/2013/08/130819-hawaiian-monk-seal-crittercam-conservation-ocean-science/?source=hp_dl2_news_hawaii_seals_20130820 | 
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