Random Samples

Science  01 Aug 2008:
Vol. 321, Issue 5889, pp. 617

    Just in time for the start of the Beijing Summer Games, German researchers announced last month that they had located traces of one of ancient Olympia's most famous racecourses. The hippodrome, where chariot races took place, was the largest structure in the ancient Greek sports complex. Described in several ancient texts, the course was also the site of Roman Emperor Nero's quest for Olympic laurels in 67 C.E. (He won them despite falling out of his chariot.)

    Archaeologists began excavating the site more than a century ago but found no sign of the racecourse and assumed that flooding from the nearby Alfeiós River had washed it away. A recent reinterpretation of a medieval text prompted sports historian Norbert Müller of the University of Mainz and colleagues to look again. Using geomagnetic mapping and georadar, the team found evidence of long, parallel ditches, walls, and earthworks along a 1.2-kilometer stretch about 2 meters below the current surface. The proportions and location—south of the already excavated stadium—match those of the ancient texts. The find is not a huge surprise given the texts' descriptions, says Paul Christesen, a classicist at Dartmouth College. But further digging should prove interesting, he says, because few hippodromes from the period have been excavated.


    If you're looking for some action, forget about the latest Hollywood blockbuster and check out a stimulated neuron. Ions stream into and out of the cell, membrane channels open and slam shut, impulses speed along the axon, neurotransmitters spill into the synapse. Nervoussystem newbies can watch these events unfold at Neurons, an animated primer from neuroanatomist Patricia Stewart of the University of Toronto in Canada and colleagues.

    The eight chapters detail the structure and workings of the excitable cells. Readers can follow along, step by step, as neurons load up on sodium ions in preparation for firing, depolarize, and then release neurotransmitters. One sequence, for example, illustrates how cocaine leads to prolonged activation of brain neurons and euphoria. Like a monkey wrench in a machine, the cocaine molecule jams the pump that normally removes the neurotransmitter dopamine from synapses. As a result, neurons keep firing.



    Last year, scientists reported that the first chickens in the New World might have come from Polynesia. Now, a new DNA analysis contradicts that notion, instead linking the bird to its European kin. The result bolsters claims that chickens first arrived in South America with Spaniards in the 15th century.


    The study, published online 28 July in the Proceedings of the National Academy of Sciences, refutes findings in an earlier PNAS paper, in which Alice Storey of the University of Auckland in New Zealand and colleagues analyzed chicken mitochondrial DNA (mtDNA) from a bone recovered from an archaeological dig in Chile. Radiocarbon analysis of the bone dated the bird to just before the Spanish arrived, and some mtDNA sequences seemed to match those in Polynesian chickens. But those sequences are also common to European chickens, says a team led by Jaime Gongora of the University of Sydney in Australia. The new analysis of mtDNA of 41 modern Chilean chickens found no trace of a uniquely Polynesian sequence. And wear and tear on the bone from the marine climate could have affected carbon-dating results, the researchers report.

    Smithsonian Institution archaeologist Bruce Smith, who was not involved in either study, says the new results demonstrate the importance of replicating studies. “This shows that science works,” he says.



    Virgin Galactic and its competitors hope to send commercial passengers to the edge of space for several minutes of zero gravity when their new suborbital airlines start operations. NASA is considering sending scientists, too. The space agency has asked researchers to design experiments that could be conducted aboard the commercial ships to make what NASA calls “astronomical, solar, planetary, and Earth observations at wavelengths and special observing geometries not accessible from the ground.”

    Astronomer Daniel Durda helped develop the idea while working with NASA's science directorate. Durda, now at Southwest Research Institute in Boulder, Colorado, has observed asteroids from F-18s, obtaining data that weather often obscures from observatories on the ground. Suborbital flights could offer other scientists similar opportunities, he says.

    “We're looking for creative new thinking,” says NASA's Kelly Snook. Virgin is aiming for commercial flights in 2009 and has booked more than 200 tickets at $200,000 each for the 5-minute excursions. Each flight, which will hold six passengers, will reach 100 kilometers in altitude. Other companies developing suborbital aircraft, including Amazon founder Jeff Bezos's Blue Origin, would also be eligible for the program.