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This press release is copyright Nature. VOL.442 NO.7104 DATED 17 AUGUST 2006
This press release contains:
· Summaries of newsworthy papers:
Brain development: Gene that might have driven the evolution of human brain revealed
Planetary science: Caps off to carbon dioxide on Mars
Microbiology: Unseen Archaea vital to nitrogen cycle
Quantum physics: Taking electrons for a spin
And finally… Watching early galaxies take shape
· Mention of papers to be published at the same time with the same embargo
· Geographical listing of authors
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[1] Brain development: Gene that might have driven the evolution of human brain revealed (AOP) DOI: 10.1038/nature05113
***This paper will be published electronically on Nature's website on 16 August at 1800 London time / 1300 US Eastern time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 17 August, but at a later date.***
Genetic comparisons between humans and other animals have identified a gene that may help in making humans unique. Intriguingly, the gene is expressed during the embryonic development of the neocortex, the site of many of the brain's most sophisticated processes.
Researchers led by David Haussler initially found the genetic sequence by comparing the human genome with those of the chimp, mouse and rat in a bid to find regions that have evolved particularly rapidly since we diverged from these other species, and which might, therefore, have been key players in shaping human evolution.
Now, as they report in a paper to be published online this week by Nature, they have found that this genetic region contains a gene, called HAR1F, which is expressed during brain growth before birth. The gene, which produces an RNA molecule rather than a protein, is expressed in cells called Cajal–Retzius neurons during the crucial period of 7 to 19 weeks of gestation, when many of the nerve cells of the neocortex are establishing their functions within the brain.
CONTACT
David Haussler (Howard Hughes Medical Institute and University of California, Santa Cruz, CA, USA)
Tel: +1 831 459 2105; E-mail: [email protected]
[4] & [5] Planetary science: Caps off to carbon dioxide on Mars (pp 790-792; 793-796)
Mars has two polar ice caps — each consisting of a permanent, central portion made up of water ice and a seasonal, thin layer of frozen CO2, which extends down to latitude 60° during the winter. During the summer, the CO2 vaporises and subsequently condenses over the opposite pole, which is experiencing winter. This week in Nature two papers discuss how this may happen.
The reflectivity of the southern ice cap is very low, and it has been proposed that this is because the CO2 ice is so clear that the underlying ground can be seen. Now Yves Langevin and colleagues show that the proposed slab of clear ice is not there. The most comprehensive observations of this region to date have been obtained with the Thermal Emission Spectrometer on board the Mars Global Surveyor spacecraft. From these images, the team consider the best explanation to be that the ice is covered with dust deposited by atmospheric circulation patterns, which is then removed as the ice cap sublimates.
In a related paper, Philip Christensen and colleagues studied infrared images of unusual dark spots, fans and blotches on the ice cap as it retreats, using the Mars Odyssey satellite. These features remain much colder than previously thought, so the team conclude that these are not features on defrosted ground, but rather on the surface of the ice. They propose that the ice cap sublimates from the bottom, shooting jets of pressurized CO2 up through the ice and creating the infrared-observed features where the jets break through the surface.
CONTACT
Yves Langevin (Institut d'Astrophysique Spatiale, Orsay, France) Author paper [4]
Tel: +33 1 69 85 86 81; E-mail: [email protected]
(Please note the author is travelling, but can be contacted from 9 to 11 August at the following number: +33 2 96 55 87 66 or on the e-mail address above)
Philip Christensen (Arizona State University, Tempe, AZ, USA) Author paper [5]
Tel: +1 480 965 7105; E-mail: [email protected]
Please note the authors have set up a protected website under embargo for extra information about paper [5]. The URL is: http://themis.asu.edu/news-polarjets
[6] Microbiology: Unseen Archaea vital to nitrogen cycle (pp 806-809)
A genetic analysis of soil reveals that a previously overlooked group of microorganisms called Crenarchaeota could be the most abundant soil ammonia-oxidizing organisms on Earth, as reported in this week’s Nature.
Ammonia oxidation is the first step in nitrification, a key part of the nitrogen cycle that results in the formation of nitrate through microbial activity. Previously, this process, which is important for plant nutrition and leads to the release of by-product greenhouse gases, was largely attributed to certain lineages of bacteria.
Not so, say Christa Schleper and her colleagues, who investigated the abundance of the gene encoding ammonia monooxygenase (amoA) in twelve wild and agricultural European soil samples. amoA gene copies from Crenarchaeota were up to 3,000-fold more abundant than bacterial amoA genes. The authors say that estimates of ammonia oxidizing activity, including greenhouse gas emissions, will need to be re-assessed.
CONTACT
Christa Schleper (University of Bergen, Norway)
Tel: +47 5558 2665; E-mail: [email protected]
[7] Quantum physics: Taking electrons for a spin (pp766-771; N&V)
The "missing ingredient" for creating a quantum computer — the 'qubit' — from isolated electrons in microelectronic devices is demonstrated in Nature this week. Lieven Vandersypen and colleagues show that they can use a magnetic field to control the quantum state of an electron held in a kind of cage called a quantum dot, made from an ultrathin blob of a semiconducting material.
Quantum computing aims to use the principles of quantum theory to boost the power of computers, exploiting the fact that quantum objects can exist in several different states at once. If information is encoded in these states, they could be used to perform many computations simultaneously. Electrons can have different states of a quantum-mechanical property called spin — in effect, the electron could be either in the so-called 'spin up' state, representing a ‘1’ in binary code, or in the 'spin down' state, representing ‘0’.
Researchers know that single electrons confined in quantum dots can be placed in particular spin states, and that a pair of electrons can exchange spin states. But to perform quantum computing with electron spins, it is also necessary to be able to rotate the spins in a controlled manner using magnetic fields. Vandersypen and colleagues achieved this for two electrons in adjacent quantum dots. By applying pulses of a magnetic field to the electrons using a microchip circuit, the researchers showed that the two spins could be rotated coherently — that is, each of them changes in synchrony with the other. They say that the results show the feasibility of using single electron spins as the 'bits' of a quantum computer.
CONTACT
Lieven Vandersypen (Delft University of Technology, Netherlands)
Tel: +31 15 278 2469; E-mail: [email protected]
Frank Koppens (Delft University of Technology, Netherlands)
Tel: +31 15 278 1420; E-mail: [email protected]
Guido Burkard (University of Basel, Switzerland) N&V author
Tel: +41 61 267 3694; E-mail: [email protected]
[8] And finally… Watching early galaxies take shape (pp786-789; N&V)
How were the first galaxies made? An international team of astronomers has glimpsed some answers to this question by studying snapshots of a very distant galaxy, formed when the Universe was just three billion years old — a mere fifth of its current age.
The ancient galaxy is called BzK-15504, and Reinhard Genzel and colleagues have imaged it using the Very Large Telescope of the European Southern Observatory in Chile. They publish their results in Nature this week.
The earliest galaxies are thought to have condensed from gas pulled together by clumps of so-called dark matter, the still-mysterious form of matter that dominates all galaxies today. The dense gas then clumped to form stars. But no one is too sure how long this took to happen, or how galaxies acquired the disks and bulges that they have today.
Genzel and colleagues seem to have caught this process in the act in BzK-15504. This galaxy already shows signs of the rotating outer disk and central bulge characteristic of 'modern' galaxies, and the researchers think that the bulge hosts a massive black hole into which gas is being pulled. The stars in BzK-15504 are still relatively young, suggesting that the formation of the disk-and-bulge shape happened surprisingly quickly.
CONTACT
Reinhard Genzel (Max-Planck Institut für Extraterrestrische Physik, Garching, Germany)
Tel: +49 893 0000 3281; E-mail: [email protected]
Robert C. Kennicutt (University of Cambridge, UK)
Tel: +44 1223 765844; E-mail: [email protected]
ALSO IN THIS ISSUE…
[9] Multiferroic and magnetoelectric materials (pp 759-765)
[10] PML inhibits HIF-1a translation and neoangiogenesis through repression of mTOR
(pp 779-785)
[11] Spontaneous skyrmion ground states in magnetic metals (pp 797-801)
[12] Resonant slow fault slip in subduction zones forced by climatic load stress (pp 802-805)
ADVANCE ONLINE PUBLICATION
***This paper will be published electronically on Nature's website on 16 August at 1800 London time / 1300 US Eastern time (which is also when the embargo lifts) as part of our AOP (ahead of print) programme. Although we have included it on this release to avoid multiple mailings it will not appear in print on 17 August, but at a later date.***
[13] Crystal structures of a multidrug transporter reveal a functionally rotating mechanism
DOI: 10.1038/nature05076
GEOGRAPHICAL LISTING OF AUTHORS…
The following list of places refers to the whereabouts of authors on the papers numbered in this release. For example, London: 4 - this means that on paper number four, there will be at least one author affiliated to an institute or company in London. The listing may be for an author's main affiliation, or for a place where they are working temporarily. Please see the PDF of the paper for full details.
CHINA
Hefei: 8
FRANCE
Grenoble: 4
Paris: 4
GERMANY
Cologne: 6
Dresden: 11
Garching: 8, 11
Karlsruhe: 11
Neuherberg: 6
ISRAEL
Tel Aviv: 8
ITALY
Bologna: 8
Florence: 8
Padua: 8
JAPAN
Osaka: 13
Saitama: 13
Tokyo: 8
NORWAY
Bergen: 6
THE NETHERLANDS
Delft: 7
UNITED KINGDOM
Aberdeen: 6
Cambridge: 9
Edinburgh: 3
Warwick: 3
UNITED STATES OF AMERICA
Arizona
Flagstaff: 5
Tempe: 5
Tucson: 8
California
Berkeley: 8
Colorado
Boulder: 12
Nevada
Carson City: 5
New York
New York: 10
Pennsylvania
Philadelphia: 10
University Park: 6
Utah
Logan: 12
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For the UK/Europe/other countries not listed above
Katherine Anderson, Nature London
Tel: +44 20 7843 4502; E-mail [email protected]
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