|Two Years on Mars! |
Yogurt and AIDS? Nanoballerinas!
Duck-billed Dino, Egyptian Queen!
The Human-Chimp Connection!
|Two Years on Mars! |
NASA's Mars Exploration Rover Spirit welcomed the beginning of 2006 on Earth
by taking this striking panorama of intricately rippled sand deposits in Gusev
Crater on Mars. (NASA)
NASA News Release
January 24, 2006 - NASA's Mars rovers, Spirit and Opportunity, have been working overtime to help scientists better understand ancient environmental conditions on the red planet. The rovers are also generating excitement about the exploration of Mars outlined in NASA's Vision for Space Exploration.
The rovers continue to find new variations of bedrock in areas they are exploring on opposite sides of Mars. The geological information they have collected adds evidence about ancient Martian environments that included periods of wet, possibly habitable conditions.
"The extended journeys taken by the two rovers across the surface of Mars has allowed the science community to continue to uncover discoveries that will enable new investigations of the red planet far into the future." said Mary Cleave, associate administrator for the Science Mission Directorate, NASA Headquarters.
NASA's third mission extension for the rovers lasts through September 2006, if they remain usable that long. During their three-month primary missions, the rovers drove farther and examined more rocks than the prescribed criteria for success.
Opportunity begins its third year on Mars today. It is examining bedrock exposures along a route between "Endurance" and "Victoria" craters. Opportunity found evidence of a long-ago habitat of standing water on Mars.
On Jan. 3, Spirit passed its second anniversary inside the Connecticut-sized Gusev Crater. Initially, Spirit did not find evidence of much water, and hills that might reveal more about Gusev's past were still mere bumps on the horizon. By operating eight times as long as planned, Spirit was able to climb up those hills, examine a wide assortment of rocks and find mineral fingerprints of ancient water.
This synthetic image of the Spirit Mars Exploration Rover on the
flank of "Husband Hill" was produced using "Virtual Presence in
Space" technology. Developed at NASA's Jet Propulsion Laboratory,
Pasadena, Calif., this technology combines visualization and
image-processing tools with Hollywood-style special effects. (NASA)
While showing signs of wear, Spirit and Opportunity are still being used to their maximum remaining capabilities. On Spirit, the teeth of the rover's rock abrasion tool are too worn to grind the surface off any more rocks, but its wire-bristle brush can still remove loose coatings. The tool was designed to uncover three rocks, but it exposed interiors of 15 rocks.
On Opportunity, the steering motor for the front right wheel stopped working eight months ago. A motor at the shoulder joint of the rover's robotic arm shows symptoms of a broken wire in the motor winding. Opportunity can still maneuver with its three other steerable wheels. Its shoulder motor still works when given extra current, and the arm is still useable without that motor.
The rovers are two of five active robotic missions at Mars, which include NASA's Mars Odyssey and Mars Global Surveyor and the European Space Agency's Mars Express orbiters. The orbiters and surface missions complement each other in many ways. Observations by the rovers provide ground-level understanding for interpreting global observations by the orbiters. In addition to their own science missions, the orbiters relay data from Mars.
NASA's Jet Propulsion Laboratory, Pasadena, Calif., a division of the California Institute of Technology, manages the Mars Exploration Rover, Odyssey and Global Surveyor projects for NASA's Science Mission Directorate.
For information about NASA and other agency exploration programs on the Web, visit: http://www.nasa.gov/home
For images and information about the rovers and their discoveries on the Web, visit: http://www.nasa.gov/mars
|Yogurt and AIDS? |
Brown University News Release
PROVIDENCE RI January 24, 2006 — Researchers have come up with a novel delivery system for anti-AIDS drugs: milk-curdling bacteria used to make yogurt and cheese.
"We’ve found that you can engineer these bugs to secrete drugs – in this case, a viricide that disables HIV," said Bharat Ramratnam, assistant professor of medicine at Brown Medical School and attending physician at Rhode Island Hospital and The Miriam Hospital. "The hope is to use the bacteria as the basis for a microbicide which can prevent sexual transmission of HIV."
Ramratnam oversaw the bug-to-drug experiments conducted by an international team of scientists who recently published their results in the Journal of Acquired Immune Deficiency Syndromes.
Ramratnam hatched the idea a few years ago after reading about an intriguing discovery: A protein called cynovirin binds to HIV and prevents it from entering cells in the mucous membranes – a feat confirmed in both laboratory and animal studies. Ramratnam was already familiar with lactic acid bacteria, or LAB.
They help make fermented foods such as yogurt and cheese by turning carbohydrates into lactic acid. LAB are also known for their "promiscuity," or the ability to accept foreign DNA, then produce proteins called for in these new genetic recipes.
So why not introduce cynovirin DNA into these bacterial protein factories?
That’s what the research team tried. Using blasts of electric current, the team made tiny holes in LAB membranes and inserted circular bits of DNA that carry the recipe for cynovirin. The team succeeded: The genetically modified LAB began cranking out the HIV-blocking protein.
The hope is to use these bioengineered bacteria as the active ingredient in a microbicide – a foam, cream or suppository that can be applied to, or inserted into, the vagina or anus before sex to prevent HIV transmission. Scientists around the world are trying to develop these topical drugs as weapons in the battle against HIV/AIDS, which has killed more than 25 million people. According to the World Health Organization, this makes the HIV/AIDS epidemic one of the most destructive in recorded history.
Ramratnam, an internist who received his medical training before the advent of life-extending antiretrovirals, hopes to have a treatment to test in humans in three years. A microbicide using modified LAB will be tested in monkeys beginning this summer.
"Before we can move into human trials, we need to meet a few challenges in animal trials," he said. "We need to be sure that LAB make enough cynovirin and make sure that the cynovirin is effective. If that happens, we may have a terrific treatment on our hands."
Ramratnam also plans to genetically modify LAB to crank out proteins that disable salmonella, shigella, cholera and other pathogens that enter the body through the mucous membranes.
Ramratnam is a scientist with the Lifespan/Tufts/Brown Center for AIDS Research. Other members of the research team include Oliver Pusch with the Medical University of Austria, Daniel Boden from the Aaron Diamond AIDS Research Center, Sean Hannify with the Institute of Food Research, Lynne Tucker from Brown Medical School, Michael Boyd from the USA Cancer Research Institute at the University of South Alabama College of Medicine, and Jerry Wells from the Swammerdam Institute for Life Sciences.
The National Institutes of Health, the Doris Duke Charitable Foundation and the Charles E. Culpeper Biomedical Pilot Initiative funded the work.
Brown University - http://www.brown.edu/Administration/News_Bureau
|Pentagon Fired 244 Gays |
|SANTA BARBARA January 25, 2006 (US Newswire) - A University of California research center released data today showing that the military has fired 244 medical specialists under the "don't ask, don't tell" policy. The figures, which cover 1994 through 2003, the first ten years of the policy, were obtained from the Pentagon by the Center for the Study of Sexual Minorities in the Military (CSSMM) with the help of Rep. Marty Meehan. The information is being reported today by the Associated Press. |
Dr. Aaron Belkin, director of CSSMM, said the discharges provide evidence that the gay ban is hampering military readiness. "The consequences of shortfalls in medical specialists during wartime are serious," he said. "When the military lacks the medical personnel it needs on the frontlines, it compromises the well-being not only of its injured troops, but of the overextended specialists who have to work longer tours to replace those who have been discharged."
According to the new data, the 244 medical personnel discharged under the gay exclusion policy included physicians, nurses, biomedical laboratory technicians and other highly trained medical specialists. The revelation comes at a time when the military has acknowledged it is struggling with significant shortfalls in recruitment and retention of medical personnel.
According to a Senate report issued in 2003 by Sens. Christopher Bond and Patrick Leahy, hundreds of injured Guard and Army Reserve soldiers "have been receiving inadequate medical attention" while housed at Ft. Stewart because of a lack of preparedness that includes "an insufficient number of medical clinicians and specialists, which has caused excessive delays in the delivery of care."
The Center for the Study of Sexual Minorities in the Military is an official research unit of the University of California, Santa Barbara.
Princeton University News Release
January 24, 2006 - A team of Princeton researchers has untangled the mystery behind a puzzling phenomenon first observed more than a decade ago in the ultra-small world of nanotechnology.
Why is it, researchers wondered, that tiny aggregates of soap molecules, known as surfactant micelles, congregate as long, low arches resembling Quonset huts once they are placed on a graphite surface?
To fellow scientists and engineers, this question and the researchers' answer is tantalizing since the discovery gives insight into "guided self-assembly," an important technique in nanotechnology where molecules arrange themselves spontaneously into certain structures. It may also one day lead to valuable technological applications such as the creation of anti-corrosion coatings for metals and bio-medical applications involving plaque formation with proteins.
In a paper appearing in the January 13 issue of Physical Review Letters, a premier physics journal, Dudley Saville, Ilhan Aksay, Roberto Car, and their colleagues explain how they unraveled the mystery.
The scientists discovered they and others had been operating on the flawed assumption that - in response to the texture of the graphite beneath them - surfactant molecules assembled themselves into static 'Quonset Hut' shapes that stayed put.
Because of new atomic force microscope imaging done by research associate Hannes Schniepp, the Princeton scientists were able to see that the micelle structures were not static but, rather, constantly on the move, building and rebuilding themselves over and over again into the same structures.
To understand what the researchers discovered, it is helpful to switch metaphors. Now, rather than envisioning the molecular assemblies as static Quonset huts, think of them as ensembles of ballerinas in constant motion.
"We spent a year trying to describe why these rods orient themselves on the graphite surface," Saville said. "But it turns out that we had imaged the dancers in freeze-frame. What we did not take into account in our original thinking was that micelles on the surface are in constant rotary motion."
Under most conditions, small particles make tiny random movements known as Brownian motion. Powered by Brownian motion, a single surfactant can be thought of as a dancer spinning about on her own; it is impossible to predict the precise pattern of movement.
What the researchers discovered was that, when molecules assembled into a micelle and the micellar dancer moved on the graphite "stage," it did so in a choreographed fashion.
Something was overriding the rotary Brownian motion. What was it?
"Saville and his coauthors combined theory at the surfactant and micellar scales with a series of careful experiments to resolve the dilemma," said William Russel, the Arthur W. Marks '19 professor of chemical engineering and dean of the graduate school at Princeton. "Long-range van der Waals forces, which are orientation-dependent, exert a torque on the entire micelle that is strong enough to overcome the randomizing tendency of Brownian motion."
Metaphorical translation: "When micelles appear on the graphite stage, they begin dancing to the music of a van der Waals orchestra," Saville said. The van der Waals interactions – weak links between the electron clouds of the micelles and the graphite below– make the micelles orient in specific directions. Basic work by research associates Je-Luen Li and Jaehun Chun provided a description of the angular variation of the van der Waals interaction and this enabled the group to close the loop.
The scientists said their work opens new horizons to explore. They still have not figured out, for example, how micelles interact with one another on the surface to form large patterned arrays. Or how the micelles disintegrate and reform in the same patterns.
"You need a critical number of dancers for this to happen but we have no idea how many," Aksay said. Moreover, he noted, the researchers can now move on to other interesting questions now that they know that the micelles are dynamic and understand the time frame in which they move. "This opens up the prospect for even more rigorous thinking."
Princeton University - http://www.princeton.edu
|Duck-billed Dino News |
University of Toronto News Release
January 24, 2006 - After decades of debate, a U of T researcher has finally determined that duck-billed dinosaurs' massive but hollow crests had nothing to do with what many scientists suspected -- the sense of smell.
Speculation about their function has led to theories that the crests functioned as everything from brain coolers to snorkels for underwater feeding.
Now, David Evans, a PhD student in zoology at the University of Toronto at Mississauga, has been able to use a reconstructed brain cavity to rule out one historically popular theory: that the crests evolved to increase the animal's sense of smell.
"From the brain case, there's no indication that the nerves curled upwards into the crest, as we would expect if the crest was used for the sense of smell," Evans says.
"It appears that the brain changed very little from their non-crested dinosaur ancestors, and that the primary region of the sense of smell was located right in front of the eyes – and coincidentally, that's where it is in birds, crocodiles, mammals and basically all four-legged animals."
Evans studied fossils from a group of herbivorous dinosaurs called lambeosaurs, which are often referred to as crested duck-billed dinosaurs. Lambeosaurs are easily recognizable for their large cranial crests, which contain elongated nasal passages and loop over their skull.
Duck-billed dinosaurs are sometimes referred to as the "Cows of the Cretaceous period" and lived 85 million to 65 million years ago.
Evans reconstructed the dinosaurs' brain cavity using well-preserved fragments of fossilized bone and created the first-ever cast of the lambeosaur brain, which is approximately the size of a human fist. The findings add weight to two currently popular theories: that the crests were used to create resonant sounds to attract mates or warn of predators, or that they were used for visual display in mate selection or species recognition, similar to feather crests in some birds.
University of Toronto - http://www.utoronto.ca
|Egyptian Queen Found! |
Johns Hopkins University News Release
January 24, 2005 - A Johns Hopkins University archaeological expedition in Luxor, Egypt, has unearthed a life-sized statue, dating back nearly 3,400 years, of one of the queens of the powerful king Amenhotep III.
The statue, which dates to between 1391 and 1352 B.C.E., was uncovered earlier this month by the expedition's director, Betsy Bryan, Johns Hopkins professor of Egyptian art and archaeology. Bryan and a graduate student, Fatma Talaat Ismail, were clearing a portion of the platform of the temple of the goddess Mut in Luxor, an area dating to about 700 B.C.E. The statue, which was lying face down in the ground, appeared to have been used as building rubble, Bryan said.
The statue's back pillar was unearthed first and led Bryan to believe briefly that it dated from a far later period, since an inscription there was clearly made in the 21st Dynasty, about 1000 B.C.E., for a very powerful queen Henuttawy.
"The statue, however, when it was removed, revealed itself as a queen of Amenhotep III, whose name appears repeatedly on the statue's crown," Bryan said. She said she theorizes that perhaps this statue is of the great Queen Tiy, wife of Amenhotep III and mother of the so-called heretic king Akhenaten, who came to the throne as Amenhotep IV but later changed his name because of his rejection of the god Amen in favor of the sun disk Aten.
"Tiy was so powerful that, as a widow, she was the recipient of foreign diplomatic letters sent to her from the king of Babylonia in hopes that she would intercede with her son on behalf of the foreign interests," Bryan said. "Some indications, such as her own portraits in art, suggest that Tiy may have ruled briefly after her husband's death, but this is uncertain."
For reasons relating to inscriptions found on it, the statue of the queen definitely may be dated to the late years of Amenhotep III's 38-year rule, Bryan said.
"The king did marry his own daughter, princess Sit-Amun, and made her his great royal wife as Tiy became more elderly," Bryan said. "Thus the statue could also represent Sit-Amun as queen. Research on this highly detailed and exquisitely worked large-scale statue is only beginning. More story will be revealed."
The discovery was made during Bryan's 11th annual excavation at the Mut Temple Precinct, where she and her students are exploring the Egyptian New Kingdom (1567 to 1085 B.C.E.). The crew shares its work with the world through "Hopkins in Egypt Today," an online diary featuring images by university photographer Jay VanRensselaer and captions by Bryan, detailing the day-to-day life on an archaeological dig. It is located at http://www.jhu.edu/neareast/egypttoday.html
Johns Hopkins University - http://www.jhu.edu
|Ancient Peruvian Factories! |
|Universitat Autònoma de Barcelona News Release |
Obsidian tools from El Trigal.
January 24, 2006 - A research team from the Universitat Autònoma de Barcelona has discovered a new type of construction, unknown until now, in the archaeological region of Puntilla, in the province of Nazca, Peru. These yards, built with stone walls, situated in the centre of the village, is where people went to work, either in agricultual or in the crafts. The yards date from the first millenium BC, but their exact date is yet to have been determined.
These results come from the analysis of archaeological excavations in the 2005 La Puntilla Project, which ended last December. The project aims to produce sociological research on the communities living in the Nazca province – where the archaeological area of La Puntilla is situated – on the south coast of Peru in the first millenium BC. The researchers have worked in two sites in the area.
They have found evidence of a new type of unique building that had not yet been found anywhere. The buildings are yards built with stone walls, located in the centre of the village. The excavation of part of one of these buildings, at the peak of the El Trigal site, has shown that the buildings were for centralised work, and not for cermonies as was first thought. The researchers have found evidence for a large number of agricultural processing tasks and craftsmanship.
The work undertaken in these buildings included making andesite and obsidian tools, manufacturing ornaments on marine shells, weaving and spinning and food processing. It is particularly remarkable that Spondylus shells were found, as these must have been brought from distant lands, probably from the coastline of what is now Ecuador. This means that the community living in La Puntilla, in the phase known by historians as Ocucaje 8, had access to goods that had covered large distances. The team of scientists now hopes to use radiocarbon dating to gain a more precise idea of the period of the first millenium BC in which the building excavated in El Trigal began operating.
Spondylus and collar from the central
building in El Trigal.
The excavations have also uncovered domestic units that show the availability of the products manufactured in the centre of the settlement. This means it will be possible to analyse distribution and production and whether there was a dominant class controlling production.
It is hoped that as excavations continue over the next few years, we will be able to understand how those living in the Nazca region during the most primitive periods of the Paracas and Nazca civilisations. This period came shortly before the Nazca culture became firmly established at the start of the first century AD, and is therefore of great historical interest.
The excavations were conducted by researchers from the Universitat Autònoma de Barcelona and the University of Almería and directed by Professor Pedro V Castro Martínez and Juan Carlos de la Torre Zevallos, of the UAB Department of Prehistory. Archaeologists from the Universidad Nacional Mayor de San Marcos and the Pontifícia Universidad Católica del Perú also took part. Funding came from the Ministry of Culture as part of the Archaeological Projects Abroad programme.
Universitat Autònoma de Barcelona - http://www.uab.es
|The Human-Chimp Connection |
Georgia Institute of Technology News Release
January 24, 2006 - Scientists at the Georgia Institute of Technology have found genetic evidence that seems to support a controversial hypothesis that humans and chimpanzees may be more closely related to each other than chimps are to the other two species of great apes – gorillas and orangutans. They also found that humans evolved at a slower rate than apes.
Appearing in the January 23, 2006 issue of the Proceedings of the National Academy of Sciences, biologist Soojin Yi reports that the rate of human and chimp molecular evolution – changes that occur over time at the genetic level – is much slower than that of gorillas and orangutans, with the evolution of humans being the slowest of all.
As species branch off along evolutionary lines, important genetic traits, like the rate of molecular evolution also begin to diverge. They found that the speed of this molecular clock in humans and chimps is so similar, it suggests that certain human-specific traits, like generation time, began to evolve one million years ago - very recently in terms of evolution. The amount of time between parents and offspring is longer in humans than apes. Since a long generation time is closely correlated with the evolution of a big brain, it also suggests that developmental changes specific to humans may also have evolved very recently.
In a large-scale genetic analysis of approximately 63 million base pairs of DNA, the scientists studied the rate at which the base pairs that define the differences between species were incorrectly paired due to errors in the genetic encoding process, an occurrence known as substitution. "For the first time, we've shown that the difference in the rate of molecular evolution between humans and chimpanzees is very small, but significant, suggesting that the evolution of human-specific life history traits is very recent," said Yi.
Most biologists believe that humans and chimpanzees had a common ancestor before the evolutionary lines diverged about 5-7 million years ago. According to the analysis, one million years ago the molecular clock in the line that became modern humans began to slow down. Today, the human molecular clock is only 3 percent slower than the molecular clock of the chimp, while it has slowed down 11 percent from the gorilla's molecular clock.
This slow down in the molecular clock correlates with a longer generation time because substitutions need to be passed to the next generation in order to have any lasting effect on the species.
"A long generation time is an important trait that separates humans from their evolutionary relatives," said Navin Elango, graduate student in the School of Biology and first author of the research paper. "We used to think that apes shared one generation time, but that's not true. There's a lot more variation. In our study, we found that the chimpanzee's generation time is a lot closer to that of humans than it is to other apes."
The results also confirm that there is very little difference in the alignable regions of the human and chimp genomes. Taken together, the study's findings suggest that humans and chimps are more closely related to each other than the chimps are to the other great apes.
"I think we can say that this study provides further support for the hypothesis that humans and chimpanzees should be in one genus, rather than two different genus' because we not only share extremely similar genomes, we share similar generation time," said Yi.
Even though the 63 million base pairs they studied is a large sample, it's still a small part of the genome, Yi said. "If we look at the whole genome, maybe it's a different story, but there is evidence in the fossil record that this change in generation time occurred very recently, so the genetic evidence and the fossil data seem to fit together quite well so far."
Georgia Institute of Technology - http://www.gatech.edu