Category Archives: Science

Evidence of Short DNA Segment Self Assembly

Tiny DNA Molecules Show Liquid Crystal Phases, Pointing Up New Scenario For First Life On Earth, University of Colorado:

CU-Boulder physics Professor Noel Clark said the team found that surprisingly short segments of DNA, life’s molecular carrier of genetic information, could assemble into several distinct liquid crystal phases that “self-orient” parallel to one another and stack into columns when placed in a water solution. Life is widely believed to have emerged as segments of DNA- or RNA-like molecules in a prebiotic “soup” solution of ancient organic molecules.
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Such DNA polynucleotides had previously been shown to organize into liquid crystal phases in which the chains spontaneously oriented parallel to each other, he said. Researchers understand the liquid crystal organization to be a result of DNA’s elongated molecular shape, making parallel alignment easier, much like spaghetti thrown in a box and shaken would be prone to line up in parallel, Clark said.

The CU-Boulder and University of Milan team began a series of experiments to see how short the DNA segments could be and still show liquid crystal ordering, said Clark. The team found that even a DNA segment as short as six bases, when paired with a complementary segment that together measured just two nanometers long and two nanometers in diameter, could still assemble itself into the liquid crystal phases, in spite of having almost no elongation in shape.

Structural analysis of the liquid crystal phases showed that they appeared because such short DNA duplex pairs were able to stick together “end-to-end,” forming rod-shaped aggregates that could then behave like much longer segments of DNA. The sticking was a result of small, oily patches found on the ends of the short DNA segments that help them adhere to each other in a reversible way — much like magnetic buttons — as they expelled water in between them, Clark said.
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“In essence, the liquid crystal phase condensation selects the appropriate molecular components, and with the right chemistry would evolve larger molecules tuned to stabilize the liquid crystal phase. If this is correct, the linear polymer shape of DNA itself is a vestige of formation by liquid crystal order.”

New Triceratops Ancestor

Alberta palaeontologists discover new dino genus

Scientists from the Royal Tyrrell Museum and the Canadian Museum of Nature have [discovered]… Eotriceratops xerinsularis (pronounced EE-OH-try-sair-ah-tops ZEER-in-soo-lair-iss)… The dino may be an ancestor of the well-know triceratops, and at the very least, is the group’s earliest known member; researchers say the Eotriceratops lived in southern Alberta 68 million years ago.

It is the largest type of horned dinosaur ever discovered in Alberta, and possibly the world.

According to researchers, Eotriceratops likely reached eight or nine metres from nose to tail. It had a massive skull that featured a solid frill (this alone was three metres in length), and three horns – two above each eye, and another, shorter one, perched on its nose.
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Judging by its teeth, the Eotriceratops was a plant-eater, but one that would have been able to ward off predators.

Who Should Profit from Yellowstone’s Microbes

The Gold in Yellowstone’s Microbes

Year by year, Yellowstone’s hot waters are yielding remarkable new microbial specimens with implications for medicine, agriculture and energy, as well as offering clues to the formation of earliest life on Earth and maybe even on Mars. The potential financial windfalls are enormous, as evidenced by one big jackpot.
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Yellowstone microbes (and those from a few other hot spots on the planet) may also hold great promise for bioremediation — cleaning up chemical pollution, oil slicks and smokestack emissions — as well as the means to accelerate biomass fermentation and develop drought-resistant crops. And there is more to be discovered: Probably less than one percent of Yellowstone’s microscopic life forms have been discovered and studied.
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the National Park Service signed a secretive research-sharing agreement with Diversa Corporation in 1998. Non-profit groups quickly cried “bio-piracy!” when they found out and sued the Service over the arrangement. While a federal court dismissed the case, it ordered the Park Service to address the issue… But the Park Service is still trying to come up with an acceptable, benefits-sharing agreement that might allow bio-prospecting of microbes and disclosure of findings, with a fair return to the Park from any commercial success.

Nigersaurus

photo of the Nigersaurus Jaw Bones

Structural Extremes in a Cretaceous Dinosaur

Nigersaurus taqueti shows extreme adaptations for a dinosaurian herbivore including a skull of extremely light construction, tooth batteries located at the distal end of the jaws, tooth replacement as fast as one per month, an expanded muzzle that faces directly toward the ground, and hollow presacral vertebral centra with more air sac space than bone by volume. A cranial endocast provides the first reasonably complete view of a sauropod brain including its small olfactory bulbs and cerebrum. Skeletal and dental evidence suggests that Nigersaurus was a ground-level herbivore that gathered and sliced relatively soft vegetation, the culmination of a low-browsing feeding strategy first established among diplodocoids during the Jurassic.

This discovery has received a good deal of coverage. Among other things it is great to see this paper is available to everyone who wants to view it because it is published by open access PLoS One. The Nigersaurus was discovered in what is now the Sahara Desert in Niger. When the Nigersaurus was roaming the area, 110 million years ago, the climate was a Mesozoic forest. The dinosaur had a few hundred teeth that were replaced almost monthly (a record). The bones of the head and neck were so minimal and light that the Read more about the Nigersaurus. As the author stated: “One of the stunning things about this animal is how fragile the skull is… Some of the bones are so thin you can shine a light through them.”

2nd Annual Science Blogging Conference

2nd Annual Science Blogging Conference will be held in North Carolina on January 19th (there are also pre-conference activities on the 18th). I unfortunately won’t make it but take a look and see if it is something you would enjoy. The program includes:

Open Science: how the Web is changing the way science is done, written and published with Dr.Hemai Parthasarathy
Blogging about the Social Sciences and Humanities with Martin Rundkvist and John McKay
Changing Minds through Science Communication: a panel on Framing Science with Chris Mooney , Jennifer Jacquet and Sheril Kirshenbaum

Open Laboratory 2007, an anthology of science blog posts will be published, as it was last year. Posts need to have been posted between 20 Dec 2006 and 20 Dec 2007 to be eligible. Submit your suggestions.

New Theory of Everything

Surfer dude stuns physicists with theory of everything

An impoverished surfer has drawn up a new theory of the universe, seen by some as the Holy Grail of physics, which as received rave reviews from scientists. Garrett Lisi, 39, has a doctorate but no university affiliation and spends most of the year surfing in Hawaii, where he has also been a hiking guide and bridge builder (when he slept in a jungle yurt).
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Despite this unusual career path, his proposal is remarkable because, by the arcane standards of particle physics, it does not require highly complex mathematics. Even better, it does not require more than one dimension of time and three of space, when some rival theories need ten or even more spatial dimensions and other bizarre concepts. And it may even be possible to test his theory, which predicts a host of new particles, perhaps even using the new Large Hadron Collider atom smasher that will go into action near Geneva next year.
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Although the work of 39 year old Garrett Lisi still has a way to go to convince the establishment, let alone match the achievements of Albert Einstein, the two do have one thing in common: Einstein also began his great adventure in theoretical physics while outside the mainstream scientific establishment, working as a patent officer, though failed to achieve the Holy Grail, an overarching explanation to unite all the particles and forces of the cosmos.

Now Lisi, currently in Nevada, has come up with a proposal to do this. Lee Smolin at the Perimeter Institute for Theoretical Physics in Waterloo, Ontario, Canada, describes Lisi’s work as “fabulous”. “It is one of the most compelling unification models I’ve seen in many, many years,” he says.

Actual open access paper: An Exceptionally Simple Theory of Everything by A. Garrett Lisi
Reactions: A Theoretically Simple Exception of Everything – Upon further review, surfer’s new Theory of Everything severely deficient
Related: String Theory – CERN Pressure Test Failure – Webcasts by Chemistry and Physics Nobel Laureates

The Brain is Wired to Mull Over Decisions

New studies have identified a specific neural circuit in the brains of monkeys that is activated when they postpone acting on a decision. The circuit is thought to keep potential choices brewing in memory even after a decision has already been made.

The brain may continue to consider the options even after a decision is made because that extra consideration may sometimes result in a change of mind – and a possible reward, such as a tastier meal. The researchers said that their findings could offer important insight into the function of neural circuits that drive the brain’s memory and decision-making machinery.
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the researchers conducted experiments in which they required the monkeys to delay their decision. At the same time, the researchers recorded the electrical activity of neurons in a region called the medial premotor cortex—one of the brain regions involved in decision-making and motor choice.

“To our surprise, when the monkeys held the decision for several seconds, what we saw in the activity of these brain cells in the medial premotor cortex is that they were still remembering the sensory information on which the decision was based,” said Romo. “During that time the neurons were recalling the first stimulus, recalling the second, comparing the second against the first, and even reporting in their activity the categorical decision.”

Remove the Identical Stretches of DNA Found in Mice, Rats, and Humans and What Happens?

A Real Genetic Headscratcher by Derek Lowe:

As you root through genomic sequences – and there are more and more of them to root through these days – you come across some stretches of DNA that hardly seem to vary at all. The hard-core “ultraconserved” parts, first identified in 2004, are absolutely identical between mice, rats, and humans.
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Even important enzyme sequences vary a bit among the three species, so what could these pristine stretches (some of which are hundreds of base pairs long) be used for? The assumption, naturally, has been that whatever it is, it must be mighty important, but if we’re going to be scientists, we can’t just go around assuming that what we think must be right. A team at Lawrence Berkeley and the DOE put things to the test recently by identifying four of the ultraconserved elements that all seem to be located next to critical genes – and deleting them.

The knockout mice turned out to do something very surprising indeed. They were born normally, but then they grew up normally. When they reached adulthood, though, they were completely normal. Exhaustive biochemical and behavioral tests finally uncovered the truth: they’re basically indistinguishable from the wild type. Hey, I told you it was surprising. This must have been the last thing that the researchers expected.

What a great example of scientists at work. It will be interesting to see where this goes.

Math and Science Education Assessment

Science Friday podcast (NPR radio programming) on the urban institute study mentioned a few weeks ago in: The Importance of Science Education.

Conventional wisdom says that U.S. students don’t measure up well against students in many foreign countries when it comes to math and science skills. But is that really true? A team of researchers have re-assessed the results of several common measures of science education success, and they say the true picture may not be as gloomy as some analysts have said.

“When it comes to math and science, American students are no worse, and often score better, than students from many leading countries,” said Harold Salzman, one of the authors of the new Urban Institute report “Into the Eye of the Storm: Assessing the Evidence on Science and Engineering Education, Quality, and Workforce Demand.” The researchers argue that some of the rankings produced by measures such as the Trends in International Mathematics and Science Study (TIMSS) are due to statistically insignificant differences in scoring.

Read the actual report – Into the Eye of the Storm, Assessing the Evidence on Science and Engineering Education, Quality, and Workforce Demand by B. Lindsay Lowell, Harold Salzman.

Scientists Chart Record Rise in Yellowstone Caldera

Scientists chart record rise in Yellowstone caldera

The floor of Yellowstone National Park’s gigantic volcano has been rising at a record rate in recent years, probably due to an underground blob of molten rock more than 14 times the size of Billings, according to a new study. The Yellowstone caldera rose nearly 3 inches a year for the past three years, faster than anyone has ever recorded. “These are rates three times (greater) than previous historic rates,” said University of Utah seismologist Bob Smith, a lead author of the study to be published in the journal Science today.

But that rapid rising isn’t an indication of an imminent volcanic eruption or hydrothermal explosion at Yellowstone, he said. It appears in line with behavior at other volcanic craters that rise and fall for thousands of years without large-scale, catastrophic eruptions. “These things go up and down,” Smith said. “That’s very common for calderas globally.”

The researchers believe the 463-square-mile slab formed from molten rock in the magma chamber beneath Yellowstone, causing the surface of the caldera to rise.