Creatures as large as elephants are unusual; it takes a long time to evolve such size.
How long does it take for a mammal as small as a mouse to evolve into something as large as an elephant? A really, really long time, a recent study has found: about 24 million generations, at minimum.
To get that number, researchers looked at the evolution of body mass over the last 70 million years, after the dinosaurs went extinct and surviving animals expanded into the ecological niches they left behind. That estimate is far longer than earlier estimates, which, extrapolating from bursts of super-fast evolution in mice, range from just 200,000 to 2 million generations. Such speedy evolution, in actuality, is probably not sustainable over the long term—hence the lengthy new estimate.
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The researchers chose to examine the sperm of crickets, because, as with humans, you can get samples of it without having the male come into contact with a female first.
What’s the News: You might already know that sperm, which can survive for only a few hours when exposed to the outside world, can live for several days in women after ejaculation. But did you know that an ant queen can fertilize her eggs with sperm she’s stored for up to 30 years? And that organisms as diverse as birds, reptiles, and insects can hang onto sperm and keep it fresh for days, weeks, or months?
Scientists studying this ability have been trying to figure out how females do it, and in a recent paper, researchers put forth evidence showing that the ladies may be arresting the aging process, by slowing down sperms’ metabolism.
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A funny thing happened after Google’s new privacy policy was announced last week. When people started checking what Google knows about them on Ad Preferences Manager—that’s the profile of you they build by watching your movements on the Web, so they can tailor ads accordingly—young women began reporting that actually, Google had aged them quite a bit. And had thought they were dudes. One young lady of our acquaintance is believed by the Ad Preferences genie to be a “65+” male. Why?
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In this graphic from the restoration authority, the land that will
be lost to erosion if the plan isn’t undertaken is shown in red.
Six years after Hurricane Katrina devastated New Orleans and the Louisiana coast, the state’s Coastal Protection and Restoration Authority has finally released a draft of a plan to try to keep it from happening again. How? By restoring the wetlands along the Mississippi River Delta, which we have more or less systematically destroyed but used to act as buffers between storm surge waves and inland cities.
Previous plans had relied on mainly on building levees and seawalls, so it’s striking that this plan, which would unroll over the course of 50 years at a cost of $50 billion, focuses on wetland restoration, writes Mark Fischetti, who has been covering this issue for Scientific American for years. Here’s how it would work:
Along the outer edge of the torn-up coast, furthest from New Orleans, former barrier islands that have been worn to thin wisps of land would be broadened with sandy sediment, mostly dredged from the ocean bottom and conveyed through pipelines. Natural ridges of land along the coast would be strengthened in similar fashion. Together, the islands and ridges would form a dotted line around southeastern Louisiana that can cut down storm surges. They would not all connect, so wind-driven water could still find its way through, but the many segments would break up the incoming wavefront into chaotic eddies flowing in conflicting directions that would at least partially cancel out one another.
The plan is already drawing ire from fishermen, who say that current restoration projects haven’t had much effect, and that all this shuttling of sand and water will interfere with their livelihoods.
Read more at Scientific American.
Images courtesy of the Coastal Protection and Restoration Authority
We’ve written before about hapless business owners practically handing hackers customers’ information by failing to observe basic computer security (Subway, we’re looking at you). But this is a security fail on a whole different level. A researcher has just revealed that about ten thousand systems controlling water plants, sewage plants, and other infrastructure are online, mostly unprotected and findable with a simple search.
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If you think of your personal computer as almost an extension of yourself, a recent federal court ruling in Colorado sounds a little disturbing. The court has ordered that a woman decrypt files on her laptop so they can be used by prosecutors against her. The woman, who is being tried for mortgage fraud, argued that this is a violation of her Fifth Amendment right to keep from testifying against herself, but the court sees the matter differently. Timothy Lee at Ars Technica’s explanation of the problem gets to the heart of it:
In previous cases, judges have drawn a distinction between forcing a defendant to reveal her password and forcing her to decrypt encrypted data without disclosing the password. The courts have held that the former forces the defendant to reveal the contents of her mind, which raises Fifth Amendment issues. But Judge Robert Blackburn has now ruled that forcing a defendant to decrypt a laptop so that its contents can be inspected is little different from producing any other kind of document.
For some, being forced to decrypt your computer and handing over your password to investigators so they can decrypt it might not seem that different—what’s hidden by your password might well feel as much a part of your mind as your password. But when you think about the precedent a ruling in the other direction might set, things get cloudier. The Department of Justice argues that if encryption is all that’s required to keep documents out of the hands of the courts, then potential child pornographers, drug smugglers, and others can refuse to hand over evidence on the grounds that it’s encrypted. Hmmm.
Another case from this week that shows the difficulty of aligning the modern sense of privacy with the law. The Supreme Court ruled that sticking a GPS device on a suspect’s car to track his whereabouts, without a warrant, is unconstitutional. But the court was divided as to why, on a very important point.
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Vultures eating a gazelle.
By now, you’re probably familiar with the Body Farm at University of Tennessee. It’s one of the places where bodies donated to science go to rot while being closely observed by appreciative forensic scientists, and we say that with the greatest respect: if not for the brave few who gave their mortal remains to be studied, we would have a much harder time telling when and how people found in fields, woods, and other unusual locales died. Now, scientists working at another Body Farm-like facility, Texas State University’s Forensic Anthropology Research Facility, have performed a fascinating study to see exactly what happens when a human body is eaten by vultures.
Their findings imply that vultures can take much longer—37 days instead of 24 hours—to find a body than the carcass of a pig left in the wilderness, which is what previous studies in the Texas facility have used. On the other hand, vultures can also pick clean, or skeletonize, a body much faster than we’d thought: it took just 5 hours instead of the expected 24. The scientists also tracked where the vultures spread the body parts that they didn’t consume, as they kept visiting the body over the following five months, which will be useful in figuring out how far away a body might be if a bone or other part is found by itself in future forensic investigations.
[via New Scientist]
Image courtesy of appenz / flickr
Family reunion time!
Digging around in your DNA is getting cheaper and easier all the time. For only $207, you can now subscribe to 23andMe’s genotyping service, for instance, which gives you information about your genetic background, potential disease susceptibilities, and other traits. And as the numbers of people in such companies’ databases climb into the hundreds of thousands, it has become possible for software to connect customers who share so much DNA, they may well be relatives. For adoptees who don’t have access to their adoption records and are curious about biological family, there’s never been a better time to go searching. The New York Times follows the story of one 42-year-old woman who, after learning she was adopted, finds her third cousin through a DNA service, and details the relationship that they form as she deals with the revelation that she is not, after all, the daughter of her adoptive parents.
About five weeks after shipping off two tiny vials of her cells from a swab of her cheek, Mrs. Vaughan received an e-mail informing her that her bloodlines extended to France, Romania and West Africa. She was also given the names and e-mail addresses of a dozen distant cousins. This month, she drove 208 miles from her hometown here to Evansville, Ind., to meet her third cousin, the first relative to respond to her e-mails. Mrs. Vaughan is black and her cousin is white, and they have yet to find their common ancestor. But Mrs. Vaughan says that does not matter.
“Somebody is related to me in this world,” she said. “Somebody out there has my blood. I can look at her and say, ‘This is my family.’ ”
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With their majestic peaks, imposing canyons, and lofty designation, America’s national parks seem inviolate, places of natural grandeur far from the vagaries of money or politics. But over the years, 26 sites have lost their national park status. In a slideshow at National Geographic, Brian Handwerk explores why.
A few parks were less-than-ideal candidates to begin with (the National Park Service running the Kennedy Center? huh?). But more often than not, the decision to jettison a park from the list came down to economics: Several parks, like Montana’s Lewis and Clark Caverns, above, were too remote to attract enough visitors; the caverns are now part of the state’s park system. Other ex-parks, however, are no longer open to the public: a Palm Beach retreat that proved too expensive for the government to maintain was bought by Donald Trump—and made into a swanky, exclusive club.
Read the rest at National Geographic.
Image courtesy of Montana State Parks
Tulips in the rocks.
Artist’s conception of what the living creatures would have looked like.
The Burgess Shale fossil beds in the Canadian Rockies are famous for showing us some of the creepiest evolutionary dead-ends to ever grace the planet. They conjure up underwater scenes of many-legged spiky creatures scuttling beneath gigantic spider shrimp, but a recent find in the Burgess Shale suggests a more pastoral landscape: fields of waving tulip-shaped creatures, each about 8 inches high.
These newly discovered filter feeders, named Siphusauctum gregarium by their discoverers, have been found in clumps of over 65, and appear to have fed by sucking water through their bodies and extracting food particles.
Images courtesy of Royal Ontario Museum and Marianne Collins.
[via ScienceDaily]
Shiga toxin is nasty stuff. If you are infected with a Shiga-producing bacterium, like Shigella dysenteriae or some E. coli strains, there is no clear treatment: if you are given antibiotics, your infected cells will explode, spraying the toxin all over neighboring cells and exacerbating your symptoms. Each year, 150 million people are infected with Shiga-producing bacteria, which cause dysentery and food poisoning, and a million of those die. The lack of effective treatment for such Shiga toxicosis infections is one of the main reasons this year’s outbreak of E. coli poisoning in Europe was so deadly, with more than 3,700 people infected and 45 dead. But now scientists studying how the toxin makes its way around the cell have discovered that treating mice with the metal element manganese makes them resistant to Shiga poisoning. Since manganese’s chemistry is already well understood and it’s readily available, the possibility of using it as a treatment is exciting.
Here’s how manganese blocks Shiga’s spread, according to the group’s experiments in cultured human cells:
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A recent column by Dr. Pauline Chen at the New York Times explores a surprising oversight in modern healthcare: Doctors don’t really have a clue how to predict how long a patient will live. In the absence of a widely accepted, systematic method of prognosis, they’re kind of making it up—an informed guess, with the benefit of education and experience, but a guess nonetheless.
Prognosis was once a diligently studied, widely practiced part of a physician’s job, Chen writes. But as treatments improved, and keeping patients alive longer became ever more possible, the unpleasant but necessary skill of predicting when patients might die fell by the wayside. A recent study, she reports, revealed just how much:
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Over the past few years, several studies have illuminated some of what happened during the brief period when modern humans and Neanderthals overlapped in Europe, with genetic analyses showing that the two groups interbred tens of thousands of years ago (though not frequently) and ancient remains suggesting that modern humans fought and—more controversially—ate their prominent-browed contemporaries.
It seems that humans and Neanderthals made occasional love and intermittent war, but what were those interludes of interaction actually like? What was going on inside those distinctive crania? It’s a tricky question to answer—behavior doesn’t fossilize—but anthropologist Thomas Wynn and psychologist Frederick L. Coolidge combine genetic and anthropological evidence with a healthy dose of well-informed speculation to offer an intriguing picture of how Neanderthals may have lived, thought, felt, and acted.
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Artist’s rendering of a mitochondrian, the energy-producing
cellular structure affected by ARSACS
Scientists have pinpointed the cause of a rare, fatal neurodegenerative disorder called ARSACS, or autosomal recessive spastic ataxia of Charlevoix-Saguenay. The disease is due to defects in neuron’s mitochondria, the bit of biological machinery that generates energy for the cell—a structure known to be affected in Parkinson’s, Alzheimer’s, and other neurological diseases, as well.
ARSACS was first observed in the descendants of a small group of 17th century French settlers who made their homes near the Charlevoix and Saguenay rivers in what is now Quebec, and has since been seen worldwide. But its incidence remains unusually high in that particular French Canadian community, with 1 in 1,500 to 2,000 people developing ARSACS and 1 in 23 people unaffected genetic carriers of the disease.
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When tuberculosis kills lung tissue, it can produce gaping
holes like in the lung on the right.
For a long time, tuberculosis was a gruesome and incurable disease. Antibiotics changed that, but over the last century, as the drugs have been incorrectly used, the tuberculosis bacterium has been developing resistance to them. Multi-drug resistant tuberculosis, which requires a cocktail of many drugs to treat it, has become common. Now Indian doctors have reported in a medical journal that a strain that is resistant to all known drugs for tuberculosis has appeared in Mumbai. Twelve patients so far have been diagnosed with the strain, and it’s likely that they are just the tip of the iceberg in terms of those infected.
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