ريتشارد دوكنز's Blog, page 662
October 17, 2015
Cassini Orbiter Sends Closest Northern Views Of Enceladus
Photo credit:
Enceladus via the Cassini Orbiter's Imaging Science Subsystem - Wide Angle. NASA/JPL-Caltech/Space Science Institute
NASA’s Cassini spacecraft completed the first of three final flybys of Saturn’s icy moon, Enceladus. On October 14, Cassini passed within 1,838 kilometers (1,142 miles) of Enceladus, providing unprecedented views of the moon’s north polar region.
This marked Cassini’s 20th close flyby of the icy snowball-like moon since arriving at Saturn over a decade ago. A handful of images were downlinked yesterday in honor of the spacecraft’s 18th launch anniversary, with more to come over the next several days.
Watch Monster Magnetic Putty Devour Metal Objects
Photo credit:
Joey FX/Science Channel via YouTube
In this video from Science Channel, we see the awesome (albeit oddly unsettling) magnetic putty in action.
How A Shark Attack Saved A Man’s Life
Photo credit:
Elias Levy/Flickr. (CC BY 2.0)
This incredible tale of luck starts with Eugene Finney on holiday in Huntington Beach, California, with his two children and girlfriend.
"The surf was pretty big that day," Finney said to Mercury News, "The waves were about 7 to 9 feet [2.1-2.7 meters], and the water is pretty deep. You can't touch the bottom."
Another Controversy for the “Female Viagra”?
Addyi, the first prescription medication approved to boost female libido, hits the market today. The U.S. Food and Drug Administration has approved marketing the drug to premenopausal women whose low libido doesn’t stem from a medical or psychiatric condition, medication or other substances, but from a lack of desire characterized as hypoactive sexual desire disorder, or HSDD.
The so-called “female Viagra”—something of a misnomer because Addyi does not affect arousal as Viagra does but rather increases libido—was mired in controversy prior to its approval, in large part because clinical studies did not show dramatic improvements in sexual desire and used measures that many experts criticized as inadequate. Despite such concerns, Addyi’s drugmaker, Sprout Pharmaceuticals, was purchased by Valeant Pharmaceuticals International for $1 billion once the drug received approval.
With about 10 percent of women suffering from HSDD, Valeant projects a healthy market for this once-a-day pill, and that does not include a large group of women who are likely to be prescribed the drug for another kind of desire problem: the low libido that is a common side effect of antidepressants.
Although Addyi has not been approved by the FDA for antidepressant-induced libido problems, once a drug hits the market, doctors can prescribe it off-label for other uses other than its approved indication. Nearly one in five women in the U.S. takes an antidepressant, and as many as 70 percent report dampened sexual desire as a result.
Selective serotonin (SSRI) and certain serotonin and noradrenaline (SNRI) reuptake inhibitor antidepressants are particularly likely to cause sexual dysfunction. The exact mechanisms are not well understood but likely stem from boosting serotonin activity in the brain. Serotonin is thought to dampen libido and arousal, and also to inhibit two other neurotransmitters, norepinephrine and dopamine, that promote sexual function. Doctors have tried various strategies, including reducing dosages, prescribing “drug holidays,” and adding in other antidepressants like Wellbutrin or drugs like Ritalin, to counteract these sexual side effects, but have not found a reliable antidote. “There’s nothing really phenomenal out there to treat SSRI-induced dysfunction,” says Christina Dording, a psychiatrist who directs sexual behavior studies at Massachusetts General Hospital’s depression research division. “Clinically we use a variety of different strategies but none of them are perfect.”
Dording and many colleagues point out that no one knows whether Addyi would be effective for women whose low libido stems from antidepressants. In theory, Addyi might work, says Anita Clayton, a University of Virginia psychiatrist who is an expert in antidepressant-induced sexual dysfunction, because it inhibits the sex-dampening effects of serotonin.
In clinical trials measuring the drug’s effectiveness the manufacturer excluded subjects who were taking an antidepressant or other drugs likely to harm sexual functioning.
Despite protocols, a few women in those efficacy studies did take an antidepressant. But because the study was not designed to measure how effective Addyi was for antidepressant users or for women whose low libido stemmed from antidepressant use, any data gleaned for would be “pretty much uninterpretable,” says Leonard Derogatis, a professor of psychiatry at Johns Hopkins University who has advised the drug’s manufacturer for a decade and who conducted many of the clinical trials. Representatives from the manufacturer, Sprout, declined to comment.
Cherry-picking patients to minimize confounding variables is a common strategy in drug trials but it doesn’t reflect the reality of clinical practice, says Rosemary Basson, director of the sexual medicine program at the University of British Columbia. Because many women with HSDD also have mood disorders and take an antidepressant, it is difficult to tease out whether a woman’s libido problems stem from her depression or other mood disorder, or from her antidepressants, relationship or other issues or from HSDD—itself a controversial diagnosis. “What’s very important is to document the level of sexual function prior to treatment with the antidepressant,” says Shari Lusskin, psychiatrist and professor at Icahn School of Medicine at Mount Sinai in New York City who specializes in women’s mental health. Unfortunately, she notes, “that’s not something that’s routinely done.”
The drug’s original developer, Boehringer Ingelheim, which later sold Addyi to Sprout, did conduct a 2010 study of depressed women with low libido to gauge whether it was safe to take Addyi with an antidepressant. The data, says Clayton, who helped plan the study, showed Addyi didn’t worsen anxiety or depression, although combining the drugs slightly increased the risk of some side effects including insomnia and dizziness.
Basson, Dording and others say they would hold off on prescribing Addyi to their patients with antidepressant-induced low libido until there is promising data to support its use—especially because even in women with HSDD, libido improvement was not dramatic and there was a risk of serious side effects like fainting and very low blood pressure, especially when combined with alcohol.
But not all doctors will be so cautious. “It will be used off-label—absolutely,” says Lusskin, who also says she would not do so herself in the absence of promising data for this subgroup. “People will ask for it, and doctors will prescribe it. It’s really the doctor’s responsibility to tell patients whether something is appropriate for them or not, but I’m afraid doctors are often willing to do what patients ask.”
Sprout would not comment on whether they plan to seek additional marketing approval to treat antidepressant-induced low libido, and the new parent company, Valeant, did not respond to requests for comment. But Derogatis and Clayton, who both served as scientific advisors to the manufacturer, think it might make sense to seek additional approvals, given the large number of women suffering from antidepressant-induced low libido and the dearth of truly effective treatment.
“I know [Sprout] was considering it,” Derogatis says, although he doesn’t know whether Valeant feels the same way. “It’s a natural to start looking at what marketing population would be beneficial. And depressed women [with antidepressant-induced low libido] jump right out.”
October 16, 2015
What We’re Reading
First evolve a duck, then teach it to read
Here are some of the stories that caught NCSE’s eye this week. Feel free to share articles that crossed your screen in the comment section, or e-mail us directly during the week with things that caught your eye. We’ll add the best to our weekly posts.
When It Rains, It Pours: Historic Drought and Atmospheric Rivers, Bay Nature magazine, July–September 2015 — We all know that weather and climate are different, but there are intersection points. This article in Bay Nature magazine explores the idea that climate change can affect weather variability—specifically, that the alternating droughts and deluges that characterize California’s weather may be exacerbated by climate change. Plus in a related article you’ll get to learn all about something called the Ridiculously Resilient Ridge.
Signs of Intelligent Life, Natural History, October 2015 — Squee! Or should I say, squeal? Christina M. Colvin and Lori Marino describe their research on pig behavior, and—no surprise here—note that “evolutionary history holds one of the keys for interpreting current research on their capacities.”
The 4 Kinds of People Who Don’t Vaccinate Their Kids: And How to Change Their Minds, The Atlantic, October 6, 2015 — Research indicates that people fail to vaccinate their kids for four different reasons: complacency, inconvenience, misplaced confidence, and risk calculation. Persuading these folks to vaccinate their children means overcoming the specific obstacles that are holding them back. No surprise that the ones who have misplaced their confidence are the toughest nuts to crack.
Competition Between Global Warming and an Abrupt Collapse of the AMOC in Earth’s Energy Balance, Nature, October 6, 2015 — The title needs help from the marketing department, but the upshot of this research report is that the doomsday scenario depicted in the horrible movie The Day After Tomorrow contains a kernel of truth. The scenario is this: freshwater influx from melting glaciers in Greenland changes oceanic circulation in the North Atlantic, leading to abruptly cooler temperatures. We already knew it had happened before; this paper says it could obliterate “global warming for a period of 15-20 years” and keep temperatures lower decades longer.
Teaching the Truth about Climate Change, The New York Times, October 10, 2015 — The New York Times editorial board calls for kids to learn about climate change. Do the arguments sound familiar? Maybe that’s because NCSE’s Minda Berbeco was interviewed on background.
Searching for the Genes that are Unique to Humans, The Atlantic, October 13, 2015 — Are genes that act like “inverse Oreos” the key to what makes us human? (Mm ... creamy filling.)
Bubble Plumes off Washington, Oregon Suggest Warmer Ocean May be Releasing Frozen Methane, Science Daily, October 14, 2015 — As Scooby-Doo would say, “Ruh-row.” Methane is more than twenty times more powerful as a greenhouse gas than CO2, and there is isotopic evidence that previous large methane releases from ocean sediments may be linked to climate shifts. The warming of permafrost may also be causing releases of methane. This is all worrisome.
Teeth from China Reveal Early Human Trek Out of Africa, Scientific American, October 14, 2015 — Homo sapiens reached China around 100,000 years ago, long before we had previously thought humanity’s range expanded out of Africa. No wonder: this was before Chinese restaurants started to deliver ...
Fort Bragg’s Paper-Plate Mandate for Restaurants off the Table, San Francisco Chronicle, October 14, 2015 — In a worrisome sign of how bad the climate-change-worsened drought here in California is, one city thought to save water by forcing restaurants to use paper plates instead of washing dishes. This is at once funny and sad. Highlights how things we don't think much about—how much water and energy does it take to clean your dishes when you eat out?—are coming to the forefront in our era of making do with less.
New Spiky-Haired Mammal Roamed During Dinosaurs’ Heyday, National Geographic, October 15, 2015 — Oh, what’s this? Just a mammal from 125 million years ago, with beautifully fossilized internal organs and hair. Paleontologists aren’t quite sure how it happened, but hair and soft tissues were preserved—at the cellular level—in a newly discovered mammal from the Cretaceous of Spain. For context, it lived nearly as far before the Chicxulub meteorite ushered in the Age of Mammals as we are past that mass extinction. But we know that it had hair not unlike modern mammals, a diaphragm for breathing, and an external ear that we’d all recognize.
And in the category of Not Exactly What We’re Reading but Fun to Explore Anyhow …
Check out this tool (click on Risk Zone Map on the right side of the page) that allows you to explore how much sea level is likely to rise anywhere in the U.S. depending on how good a job we do reducing carbon emissions. Hint: we’d better get cracking.
Can You Evolve Into a Duck? This irresistible game at Clickhole — the site that satirizes the internet’s love of clickbait — brilliantly illustrates the randomness, unpredictability, joy, and frustration of evolution.
Dino’s Tail Might Have Whipped It Good
It seems the first resident of earth to break the sound barrier wasn't Chuck Yeager, after all. He was about a hundred million years too late.
Apatosaurus was a cousin of Brontosaurus, but even bigger—with a 40-foot tail more than three feet thick at the butt end but no wider than your pinky at the tip. That dainty end made the tail too fragile for clubbing attackers. So what was it for? Maybe this: [bullwhip crack]
The idea that Apatosaurus might have used its tail like a bullwhip—to scare off predators, communicate or even show off for potential mates—gained traction about 20 years ago. That’s when paleontologist Philip Currie of the University of Alberta teamed with Nathan Myhrvold to create a computer simulation that showed the whip-cracking tail was plausible. Myhrvold is the founder and CEO of Intellectual Ventures—an invention firm in the Seattle suburbs—where I’m executive editor.
This week at a meeting of the Society for Vertebrate Paleontology, Myhrvold, Currie and Dhileep Sivam, also of Intellectual Ventures, unveiled a quarter-scale physical model of an Apatosaurus tail made from aluminum vertebrae and steel tendons. [Supersonic Sauropods: The Physical Model (p. 214)]
Give the big end of the model a strong push and pull, and it does this: [audio of model crack]. Our analysis of high-speed video of the tail in action found that the tip moves at more than 800 miles an hour—fast enough to break the sound barrier and create a small sonic boom.
A full-size apatosaur whipping its tail in this way could probably have produced a sound loud enough to shatter human eardrums. Which must have really gotten their attention back in the late Jurassic.
—Wayt Gibbs
[The above text is a transcript of this podcast]
Koko The Gorilla Gets Kittens For Her Birthday
Photo credit:
Koko meets Ms Grey. kokoflix/YouTube
On her 44th birthday last July, Koko the lowland gorilla had a visit from a litter of kittens. In a fascinating, humbling and obscenely adorable video, we see Koko play with the litter, including her two adopted kittens, Ms Black and Ms Grey.
The Last Few Quito Rocket Frogs Might Be Wiped Out By Volcano
Photo credit:
Ángel M. Felicísimo/Flickr. (CC BY-SA 2.0)
To say Quito rocket frogs are having a run of bad luck would be an understatement. After 25 years of being critically endangered, they are now threatened to be fully wiped out by a volcanic eruption in Ecuador.
How To Predict The Ratio Of Males To Females In Wild Animals
Photo credit:
Green lizards (Lacerta viridis) have ZW genetic sex determination systems, even though many other reptiles exhibit XY sex determination. András Liker
In the wild, some species tend to have more males than females, while some extreme populations might be composed of adult females exclusively. According to new findings published in Nature last week, the proportion of males to females – called the adult sex ratio – in many animal populations is based on the sex chromosomes. And that ratio can be predicted too.
Ebola Beds Saved Thousands
Photo credit:
Beds designed to allow safe treatment for Ebola patients saved tens of thousands of lives, but they could have saved many more. Tandem/Shutterstock
After a week without new Ebola cases, a study has reported how much worse the epidemic could have been without the supply of treatment beds. At the same time, it reveals the price of response delay, with half of Sierra Leone's cases declared as preventable with swifter action.
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