- EPA Reverses Controversial ‘Human Guinea Pig’ Rule
- ‘Lucy’s Grandfather’ Fossil Makes Humanity’s Ancestor Seem More Like Us
- Not for Public Display: Backstage at the American Museum of Natural History
- Cassini Skims Through Titan’s Upper Atmosphere
- Video: How Leaping Fish Species Left the Water — For Good
Posted: 22 Jun 2010 01:50 PM PDT
Under proposed changes to federal research ethics standards, the Environmental Protection Agency will no longer accept studies that use people as guinea pigs in chemical tests.
In 2006, under chemical-industry pressure, and over arguments that the studies were scientifically and ethically bankrupt, the EPA declared such data acceptable. On June 16, the EPA reversed its decision.
"What we were really concerned about is toxicity studies, where they're trying to do a study on humans to determine the dose response of a chemical," said Jennifer Sass, a senior scientist at the Natural Resources Defense Council, a liberal nonprofit. "If the EPA stops accepting them, there's no motivation for companies to conduct them."
Almost every standard code of medical ethics — including the Nuremberg Code, written in response to Nazi doctors' nightmare studies — forbid human tests of drugs or chemicals that may cause harm, but can provide no direct benefit.
The chemical industry, however, has long argued that the EPA should accept data from tests in which healthy volunteers are paid for exposing themselves to pesticides and other known toxins. The industry says such data provide a more accurate picture of chemical effects than animal studies.
Critics say the resulting science is worthless, with companies running tests on small, non-representative groups of people, such as healthy young men, in order to create a false impression of safety. More importantly, the tests put people at potentially grave physical risk, with no benefit but a cash payment.
"These pesticides are intentionally designed to be toxic. Their whole purpose is to kill insects and invasive plants," wrote senator Barbara Boxer (D-CA) and representative Henry Waxman (D-CA) in a 2005 report (.pdf) on the industry's tests. "Yet in the experiments, test subjects swallowed insecticide tablets, sat in chambers with pesticide vapors, had pesticides applied to their skin, had pesticides shot into their eyes and noses, and were even exposed in their homes for six months at a time."
Continued Waxman and Boxer: "The subjects were not told of the dangers of exposure to the pesticides. Sometimes, they weren't even told the substances being tested were pesticides. They were misled into believing that they were participating in 'drug' trials, not pesticide experiments."
Nevertheless, the Bush-era EPA — led by Stephen Johnson, a former tobacco-industry scientist — said they'd accept data from those studies. The NRDC, along with liberal nonprofits Pesticide Action Network and Earthjustice, filed suit in federal court.
Proposed rule changes announced by the EPA on June 16are the result of negotiations that accompanied the legal battle. They extend protections from the Common Rule (a widely accepted set of medical ethics that forbid intentional-dosing studies that have no benefit) to all people involved in EPA-accepted studies. Extra protections are given to children and pregnant women.
"EPA expects its tougher new rules will decrease the number of systemic intentional dosing toxicity studies conducted for pesticides," reads the EPA website. "We expect the number of systemic toxicity studies to drop to as few as zero or one per year."
The rules will be opened to public comment in January of 2011, and will need court approval to finally become law.
The American Chemistry Council, the major chemical industry trade group and an advocate of expanded human testing, did not respond to requests for comment.
According to Sass, Some data on human exposures to chemicals may still be used. Reports from accidental poisonings, worker exposures and other unintentional dosing exist, and "EPA could incorporate a lot of that unfortunate, real-world data," she said.
"Pesticide companies should not be allowed to take advantage of vulnerable populations by enticing people to serve as human laboratory rats," said Pesticide Action Network senior scientist Margaret Reeves in a press release.
Image: Flickr/Michelle Tribe
Posted: 22 Jun 2010 11:28 AM PDT
A 3.6 million-year-old fossil from one of humanity's earliest ancestors is more human-like than expected — and much taller.
The discovery makes Lucy, the best-known fossil of all, appear to be exceptionally short by comparison. Lucy and the new skeleton are both Australopithecus afarensis, the first fully bipedal primate and a direct ancestor of humanity. Unlike Lucy and every other A. afarensis fossil, the new skeleton has complete forelimb and hindlimb bones, allowing researchers to estimate its size more accurately.
The new A. afarensis specimen stood a full six feet tall, or almost twice Lucy's height. Other fossil fragments suggested that Lucy was an unreliable measuring stick for A. afarensis, but the new fossil is the most conclusive evidence yet. Dubbed "Kadanuumuu," or Big Man, it is described June 21 in the Proceedings of the National Academy of Sciences.
Big Man's limbs also appear well-suited for running, in contrast to the shambling gait implied by Lucy's skeleton. The proportions compare to those found two million years later in Homo erectus, and would not be out of place in a modern human, said study co-author Owen Lovejoy, a Kent State University paleoanthropologist.
"The difference between Australopithecus and humans is much less than everyone expected," said Lovejoy. "Upright walking and running were pretty advanced at 3.6 million years ago, and they didn't change much over the next two million years. Most of the changes in that period of time took place elsewhere."
Lovejoy was also part of the team that discovered Ardipithecus ramidus, a 4.4 million-year-old possible human ancestor that was officially described last October. Ardipithecus was far less chimp-like than expected.
That raises the possibility that it's the other Great Apes, rather than humans, whose bodies have evolved the most over the last few million years.
Big Man, with a rib cage shaped more like our own than that of a chimpanzee or gorilla, reinforces that notion.
"Chimps and gorillas are again the unusual form. Hominids and ourselves bear many primitive traits that haven't been specialized like they have in gorillas," said Lovejoy.
"The classic cartoon of the ape turning into the human doesn't work at all."
Image: Yohannes Haile-Selassie/PNAS.
Citation: "An early Australopithecus afarensis postcranium from Woranso-Mille, Ethiopia." By
Posted: 21 Jun 2010 04:30 PM PDT
<< previous image | next image >>
NEW YORK CITY — You could spend three or four days in the American Museum of Natural History and still not see all the dinosaur fossils, meteorites, butterflies, lizards, diamonds and historical artifacts it has to offer. But even if you could, you would only have seen one face of the museum. In the basement, attic, turrets, back hallways and closets there's an equally dizzying array of awesome stuff.
Wired Science recently took a tour of the museum-behind-the-museum to learn about the science, art, construction and collection that make up the heart of the 140-year-old institution. From cutting-edge cryogenic tissue storage to decades-old, handmade, fossil-preparation equipment to the Big Bone Room, we learned how the museum helps discover, advance and preserve the knowledge it is best known for putting on display.
Frozen Tissue Laboratory
Getting to the various labs and back rooms of the museum involves navigating a confusing agglomeration of large spaces lined with tall cabinets containing all manner of beetle, bird and badger specimens; riding in oversized elevators; and walking down long, cluttered hallways with exposed pipes and a strange mix of outdated, faded science and safety posters on the walls. So entering the sterile, spare, high-tech frozen-tissue laboratory is like stepping into another world.
The Ambrose Monell Cryo Collection consists of eight nearly indestructible liquid-nitrogen–fueled cryogenic tanks. Three are already online, preserving 70,000 tissue samples from reptiles, amphibians, mammals, insects, fish and birds. The space can fit four more vats, and at full capacity could store and catalog a million samples.
"We have all taxa. It's one of the things that makes this collection unique," said Julie Feinstein, collections manager for the tissue lab. "All of the collections from the museum have samples here."
The cryovats take the place of the many individual collections that used to be kept in freezers in labs all over the museum. Those samples were vulnerable to power outages and even when they managed to stay frozen, they were kept between minus 4 and minus 112 Fahrenheit, which is not cold enough to prevent all damage and degradation over time. The bottom of the vats are filled with liquid nitrogen that is below minus 300, always keeping the tissue colder than minus 230.
"And the freezers don't fail," Feinstein said. Even in the event of a catastrophic power failure, the vats will stay cold for five weeks on their own. And they are on wheels, so the samples can be moved without taking them out of the freezers. There's also a dedicated staff just for the frozen collection. "So the freezers are not alone."
The tissue library is also protected against loss and misplacement by a meticulous computer tracking system that involves bar codes and human-readable numbers.
The cryostorage supports the museum's genetic-analysis and conservation studies, but the lab will store samples for any scientist with a need who is willing to relinquish ownership and share. The types of samples range from mammal blood to bird liver to whale skin. The lab recently received some samples of bats with White Nose syndrome, which threatens bat populations in the eastern United States, and is already receiving requests from other researchers to study them.
It is the premier tissue storage facility in the world, and the Smithsonian, Harvard and Yale natural history museums are hoping to model their own collections after it, Feinstein said.
Photos: Jonathan Snyder/Wired.com
Posted: 21 Jun 2010 01:39 PM PDT
The Cassini spacecraft made its deepest dip ever into the atmosphere of Titan, Saturn's largest moon, at 8:28 p.m. Eastern time on June 20. The data it collected will help determine whether the moon has its own magnetic field.
"For Titan scientists, this is one of the most anticipated flybys of the whole mission," wrote space physicist Cesar Bertucci of the Institute of Astronomy and Space Physics in Buenos Aires, Argentina in a blog post. That's saying something, as Cassini has already orbited Saturn for six years and may last seven more.
The flyby took Cassini within 547 miles of Titan's surface, about two and a half times the altitude of the International Space Station. Although this distance shaved only 43 miles off the next nearest approach, the flyby was the first to take the spacecraft below Titan's ionosphere, a layer of charged particles in the upper atmosphere. The ionosphere shielded the spacecraft from Saturn's much larger magnetic field, allowing scientists the first hints of whether Titan has a magnetic field of its own.
Earlier measurements by the Voyager spacecraft and an earlier Cassini flyby at 590 miles showed that Titan's magnetic field is weak at best, and certainly no match for Saturn's. But that doesn't mean it's not there, Bertucci said. "We'd like to know what the internal field might be, no matter how small."
Measuring the field will provide insight into the moon's internal structure. In planets like Saturn or Earth, long-lived magnetic fields are driven by currents in a metallic, liquid core. These currents arise as the planet rotates. With its thick atmosphere of nitrogen and methane and its liquid hydrocarbon lakes, Titan resembles the early Earth more than any other body in the solar system, making the moon an ideal natural laboratory for studying the origins of life. If Cassini picks up a magnetic field, it might mean that Titan, like Earth, has a liquid core.
But it might not. There are two other explanations for a magnetic Titan, Bertucci wrote. Like Mars, Titan may once have had a liquid core that has since frozen, leaving behind residual magnetism in the crust. Or, if a conducting layer like an ocean lies on or below the crust, part of the surface could have temporarily picked up some of Saturn's magnetism before Cassini got there.
The data should finish its downlink to Earth by the end of today, and a preliminary report on all the measurements from the flyby should be available by the end of the week, Bertucci told Wired Science.
Posted: 21 Jun 2010 12:28 PM PDT
Using high-speed video, researchers have revealed the biomechanical tweaks that allow a little-known fish called the leaping blenny to thrive on land.
Propelled by a twisting motion that turns their tails into springboards, leaping blennies have colonized rocky intertidal areas across the South Pacific. Closely related species still live in the ocean, but leaping blennies only go back by accident.
"None of the blennies were observed voluntarily entering the water during low or high tide," wrote Temple University biomechanicist Tonia Hsieh in a study published June 18 in Public Library of Science One.
Tsieh is one of a handful of researchers to study leaping blennies, formally known as Alticus arnoldorum. They've escaped scientific attention in part because blennies live among rocks buffeted by large, violent waves. It's a niche shared only with limpets and crabs, which could explain the evolutionary pressures favoring A. arnoldorum's terrestrial migration.
In the latest study, Hsieh studied leaping blennies and five closely-related species. Each can breathe through blood vessel-rich skin while out of water, allowing them to survive indefinitely if intermittently splashed, but only A. arnoldorum and one other blenny, Praealticus labrovittatus, venture onto land.
Hsieh used high-speed video and force-measuring plates to compare the locomotion of the different species. She found that A. arnoldorum and P. labrovittatus begin their leaps by curling their bodies into a C-shape. It's a shape seen often in the aquatic fish world as a reflexive response to danger, preceding a burst of escaping speed. The two blennies have brought it under intentional control.
Hsieh also found that A. arnoldorum has literally added a twist, rotating its tail fin sideways for extra push. This added boost likely explains its wholly terrestrial tendencies; P. labrovittatus, with its basic C-shape, is merely amphibious, and still returns regularly to the ocean.
"The terrestrial blennies have co-opted this for movement on land," Hsieh said.
Hsieh next plans to study the genetic relationships between the species, determining how the terrestrial blennies evolved and perhaps guessing how they'll evolve in the future. She also wants to study the blennies' impressive climbing abilities, which seem to involve adhesive mucus and suction-forming fins, allowing them to climb slippery, vertical surfaces.
"People say that a fish out of water is a dead fish, and that's not necessarily true," said Hsieh.
Videos: 1) Lateral view of jumping in the terrestrial blenny./Tonia Hsieh. 2) Ventral view of a terrestrial blenny, Alticus arnoldorum, climbing up a vertical piece of Plexiglas./Tonia Hsieh.
Citation: "A Locomotor Innovation Enables Water-Land Transition in a Marine Fish." By Shi-Tong Tonia Hsieh. Public Library of Science ONE, Vol. 5 No. 6, June 18, 2010.
|You are subscribed to email updates from John E Morf's Facebook notes |
To stop receiving these emails, you may unsubscribe now.
|Email delivery powered by Google|
|Google Inc., 20 West Kinzie, Chicago IL USA 60610|