June 10, 2007, 9:01 PM CT

Columbine Flowers Develop Long Nectar Spurs

In flowers called columbines, evolution of the length of nectar spurs--the long tubes leading to plants' nectar--happens in a way that allows flowers to match the tongue lengths of the pollinators that drink their nectar, biologists have found.

The researchers were Justen Whittall of the University of California at Davis and Scott Hodges of the University of California at Santa Barbara. They were funded by the National Science Foundation (NSF). Their results appear in this week's issue of the journal Nature.

Darwin once proposed a co-evolutionary "race" to explain how natural selection might account for the evolution of very long nectar spurs in flowers, said Hodges. "In Darwin's race, plants with the longest spurs and pollinators with the longest tongues [to tap the flowers' nectar] would be favored by natural selection, and--in a never-ending process--continually drive the plants' spurs and the pollinator tongues to exceptionally long lengths".

But it turns out, Whittall and Hodges found, that evolution acts in a more one-sided fashion in many plants: the plants evolve nectar spurs to match the tongue-lengths of the pollinators. Then the process stops, and only starts again when there is a change in pollinators.

Whittall and Hodges proved this idea by testing the columbine genus Aquilegia, which is pollinated by bumblebees, hummingbirds and hawkmoths......... Posted by: Beverly      Read more         Source

June 10, 2007, 7:48 PM CT

Agonized Death Of Dinosaurs

Berkeley -- The peculiar pose of many fossilized dinosaurs, with wide-open mouth, head thrown back and recurved tail, likely results from the agonized death throes typical of brain damage and asphyxiation, according to two paleontologists.

A classic example of the posture, which has puzzled paleontologists for ages, is the 150 million-year-old Archaeopteryx, the first-known example of a feathered dinosaur and the proposed link between dinosaurs and present-day birds.

"Virtually all articulated specimens of Archaeopteryx are in this posture, exhibiting a classic pose of head thrown back, jaws open, back and tail reflexed backward and limbs contracted," said Kevin Padian, professor of integrative biology and curator in the Museum of Paleontology at the University of California, Berkeley. He and Cynthia Marshall Faux of the Museum of the Rockies published their findings in the recent issue of the quarterly journal Paleobiology, which appeared this week.

Dinosaurs and their relatives, ranging from the flying pterosaurs to Tyrannosaurus rex, as well as many early mammals, have been found exhibiting this posture. The explanation usually given by paleontologists is that the dinosaurs died in water and the currents drifted the bones into that position, or that rigor mortis or drying muscles, tendons and ligaments contorted the limbs......... Posted by: Beverly      Read more         Source

Fri, 08 Jun 2007 23:25:20 GMT

Oetzi-the Iceman Bled to Death on Glacier

The 5,300-year-old Alpine Iceman or Oetzi died as a result of massive blood loss from a ruptured artery, the Swiss-Italian team working on him revealed.

It is assumed that he was trying to hide from his captors when the arrow struck him in the left shoulder slitting the artery under his collarbone. It was a quick death. This assessment is based on the presence of a flint arrowhead lodged in his back and extensive cuts to his hands.

The remains of this Neolithic man emerged from a melting glacier in 1991 on the border between Austria and Italy.

Since the discovery, researchers have been working on him to find out what all happened with the man.

A long series of investigations have been carried on him, with the latest results being published in the Journal of Archaeological Science .

The tree pollen found in his stomach reveals that Oetzi started his day with a meal in a wooded valley below the Alps. The same day he was involved in a fight that led to his death.

Recent advances in computerised tomography (CT), a sophisticated X-ray scan that allows multidimensional imaging, have given researchers an unprecedented view of Oetzi’s internal anatomy. His death was immediate because blood poured out into the surrounding tissue, forming a haematoma that can be seen in the breast cavity.

Clotted blood also entered the hole caused by the arrow’s wooden shaft, showing that it was broken off while Oetzi was still alive and therefore still bleeding.

Oetzi climbed up to the Schnalstal Glacier and died of cardiac arrest, brought on by shock, after losing so much blood.

Scientists have modelled the arrowhead embedded in his back

The University of Zurich researchers said that it is impossible to tell whether Oetzi was hit while he was walking, running, or stationary, but the speed with which he died following his injury makes it seem more likely that he was shot on the glacier, rather than in the valley below where he started his journey. But, his killer was below him either kneeling or down the hill.

Oetzi takes his name from the Oetz Valley where he was found - still wearing goatskin leggings and a grass cape. His copper-headed axe and a quiver full of arrows were lying nearby. Oetzi was about 159cm tall (5ft, 2.5in), 46 years old, arthritic, and infested with whipworm.

Initially, it was thought he died from cold and hunger, but researchers eventually established that he died from injuries sustained in a conflict.Image

Via: BBC Posted by: Scorpio_teddy      Read more     Source

June 7, 2007, 7:28 PM CT

Turning the tables in chemistry

Waltham, MAWhat do glowing veggies have to do with a career in science" It just so happens that electrified pickles swimming in metal ions are one example of the type of undergraduate chemistry class demonstration that helps make a future in science a bright possibility, rather than a total turn-off, for a number of students.

In a commentary in this months Nature Chemical Biology, Brandeis University and Howard Hughes Medical Institute (HHMI) Professor Irving Epstein outlines a gathering storm clouding the future of U.S. science and prescribes a series of strategies to help avert a looming national crisis. Epstein says the continued success of U.S. science is seriously threatened by the fact that increasing numbers of undergraduates, especially the disadvantaged, are writing off a career in science.

Why? A number of students find introductory science, and chemistry in particular, both difficult and dull the way it is conventionally taught at the college level, discouraging a number of potential researchers before they ever have the chance to get hooked on science.

Anyone who teaches an introductory science course at one of this countrys elite universities is familiar with the sea of white faces he or she encounters, and the tendency of that ocean to whiten even more as the semester progresses and as one moves up the ladder of courses, writes Epstein, who last year won $1 million from HHMI to revamp introductory chemistry at Brandeis with an eye to luringand retainingmore students in science, especially disadvantaged ones......... Posted by: Beverly      Read more         Source

Thu, 24 May 2007 00:55:19 GMT

Sharks Are Our Distant Cousins, DNA Reveals

We humans have a water-living cousin, we failed to recognize for long! Thanks to scientists for apprising us to our distant cousins sharks! Yes, we the humans and the sharks share a common ancestor as been recently revealed by our DNA study.

Its not a single gene, but one shark species sevare found to be nearly identical to those in humans!

Amazingly, it was found that an elephant shark’s genome is much similar to ours to an extent that leads to more in common with it, compared to other species — like teleost (bony skeleton) fishes — nearer to us on the evolutionary tree.

It was exciting for the scientists to find that sets of genes on chromosomes, along with actual genetic sequences are highly similar in the elephant shark and human genomes!

Many of the genes compared between the elephant sharks and humans are found to be involved in sperm production. Surprisingly, both the species are found to produce sperm that appears to have receptors on the tip, allowing fusion with a female egg.

Ah! So, meet your distant cousin, especially those who kill them to meet their own greedy ends yes, you are killing your own cousin!

Hold on for a minute and think about it, before digging that harpoon on their flesh, just to make bleedImage Posted by: Irani      Read more     Source

April 30, 2007, 8:09 PM CT

First Genome Comparison of Plankton Species

An international team of scientists led by Scripps Institution of Oceanography at UC San Diego and the Department of Energy's (DOE) Joint Genome Institute has peered into the genetic makeup of two species of phytoplankton, the tiny plants key in global photosynthesis and carbon cycling, and come away with surprising results about evolutionary engineering and new ideas about the role that a poorly understood chemical element may play in the world's oceans.

For several years, Scripps Oceanography's Brian Palenik and his collaborators, including scientists from France, Belgium and Germany, have been analyzing and annotating an organism called Ostreococcus. At one micron it is the smallest known phytoplankton and one of the smallest of all the eukaryotes, organisms with specialized internal cell structures that include plants and animals. A teaspoon of seawater taken off the Scripps Oceanography Pier typically contains more than 100,000 eukaryotic phytoplankton, which are found throughout the world's oceans. Phytoplankton are responsible for nearly half of the planet's photosynthesis.

Advances in genomics have allowed scientists to begin digging deeply into a long-standing biological puzzle concerning the mechanisms behind the divergent genomes of related photosynthetic phytoplankton species. The international team's work, published in the online edition of Proceedings of the National Academy of Sciences, is the first comparison of the genetic makeup of two closely related eukaryotic phytoplankton and the mechanisms that make them biologically similar and distinct......... Posted by: Beverly      Read more         Source

April 30, 2007, 7:03 PM CT

Seeing the trees for the forest

After completing a two-year pilot phase, researchers at the Woods Hole Research Center are expanding the scope of the "National Biomass and Carbon Dataset" for the year 2000 (NBCD2000), the first ever inventory of its kind, by moving into the production phase. Through a combination of NASA satellite datasets, topographic survey data, land use/land cover data, and extensive forest inventory data collected by the U.S. Forest Service Forest Inventory and Analysis Program (FIA), NBCD2000 will be an invaluable baseline data set for the assessment of the carbon stock in U.S. forest vegetation and will improve current methods of determining carbon flux between vegetation and the atmosphere. Work on the remaining 61 mapping zones will be completed at a rate of roughly one zone every seven working days.

As per Josef Kellndorfer, an associate scientist at the Center who is leading the project, "Understanding this flux is critical for the quantification and prediction of atmospheric CO2 concentrations, a major determinant of the greenhouse warming effect in the climate system. Thus, this initiative will directly support the North American Carbon Program, which is a major component of the U.S. Climate Change Research Program".

In the NBCD2000 initiative, begun in 2005, data is being analyzed in 66 ecologically diverse regions, termed "mapping zones", which span the conterminous United States. Within each mapping zone data from the 2000 Shuttle Radar Topography Mission are combined with topographic survey data from the National Elevation Dataset (NED) to produce a radar-based height map of vegetation. Subsequently, this map is converted to estimates of actual vegetation height, biomass, and carbon stock using survey data from the U.S. Forest Service FIA program and ancillary data sets from the National Land Cover Database 2001 (NLCD2001) project. The NLCD2001 data layers are crucial inputs to the NBCD2000 project as they provide land cover and canopy density information used in the stratification/calibration process......... Posted by: Beverly      Read more         Source

April 25, 2007, 9:18 PM CT

Closer To The Goal Of High-yield Fusion Reactor

An electrical circuit that should carry enough power to produce the long-sought goal of controlled high-yield nuclear fusion and, equally important, do it every 10 seconds, has undergone extensive preliminary experiments and computer simulations at Sandia National Laboratories' Z machine facility.

Z, when it fires, is already the largest producer of X-rays on Earth and has been used to produce fusion neutrons. But rapid bursts are necessary for future generating plants to produce electrical power from sea water. This had not been thought achievable till now.

Sandia is a National Nuclear Security Administration laboratory.

How does it work?

An automobile engine that fired one cylinder and then waited hours before firing again wouldn't take a car very far.

Similarly, a machine to provide humanity unlimited electrical energy from cheap, abundant seawater can't fire once and quit for the day. It must deliver energy to fuse pellets of hydrogen every 10 seconds and keep that pace up for millions of shots between maintenance - a kind of an internal combustion engine for nuclear fusion. That's so, at least, for the fusion method at Sandia National Laboratories' Z machine and elsewhere known as inertial confinement.

But, unable to produce fusion except episodically, the method has been overshadowed by the technique called magnetic confinement - a method that uses a magnetic field to enclose a continuous fusion reaction from which to draw power......... Posted by: Beverly      Read more         Source

April 24, 2007, 11:08 PM CT

Hibernating Bears Conserve More Strength

A fascinating new study from the May/June 2007 issue of Physiological and Biochemical Zoology quantifiably measures the loss of strength and endurance in black bears during long periods of hibernation. T.D. Lohuis (Alaska Department of Fish and Game) and his coauthors find that black bears in hibernation lose about one-half as much skeletal muscle strength as humans confined to bed rest for similar periods of time do.

"Fasting, unweighting, or immobility results in compromised muscle function," explain the authors. They continue, "Because bears are confined and anorexic for several months during winter but can still retain muscle protein and display sustained activity if disturbed, we measured skeletal muscle strength, fatigue resistance, and in vivo contractile properties of intact muscles in bears within their natural dens".

Adapting a system used for the evaluation of neuromuscular disease progression in humans, the researchers tested black bears from Middle Park, Colorado, both early and late in the hibernation cycle. After sampling, bears were placed back in their den, and the entrance was covered with pine boughs and snow.

The researchers found that after 110 days of anorexia and confinement in the den, bears lost about 29% of their muscle strength. In comparison, humans on a balanced diet but confined to bed for 90 days have been reported to lose 54% of their strength. Other studies have shown that human astronauts in a weightless environment lose 9%11% of their strength during a 17-day spaceflight......... Posted by: Beverly      Read more         Source

April 24, 2007, 10:21 PM CT

New Family of Pseudo-Metallic Chemicals

The periodic table of elements, all 111 of them, just got a little competition. A new discovery by a University of Missouri-Columbia research team, published in Angewandte Chemie, the journal of the German Society of Chemists, allows scientists to manipulate a molecule discovered 50 years ago in such as way as to give the molecule metal-like properties, creating a new, "pseudo" element. The pseudo-metal properties can be adjusted for a wide range of uses and might change the way scientists think about attacking disease or even building electronics.

Five decades ago, Fred Hawthorne, professor of radiology and director of the International Institute for Nano and Molecular Medicine at MU, discovered an extremely stable molecule consisting of 12 boron atoms and 12 hydrogen atoms. Known as "boron cages," these molecules were difficult to change or manipulate, and sat dormant in Hawthorne's laboratory for many years.

Recently, Hawthorne's scientific team found a way to modify these cages, resulting in a large, new family of nano-sized compounds. In their study, which was published this month, Hawthorne, and Mark Lee, assistant professor at the institute and first author of the study, found that attaching different compounds to the cages gave them the properties of many different metals......... Posted by: Beverly      Read more         Source