Aerosols have greater cooling effect than thought; Einstein's E=mc2 is put to the test; Martian plains not so wet?;Out of Africa challenge; Origin of tetrapod locomotion discovered; Reindeer obey different rhythms in the dark

Summaries of newsworthy papers from Nature Vol.438 No.7071 including Dance hall moves show off symmetry and sex appeal and Blast from the past


This press release is copyright Nature.
VOL.438 NO.7071 DATED 22 DECEMBER 2005

This press release contains:
* Summaries of newsworthy papers:
* Climate change: Aerosols have greater cooling effect than thought
* Sexual signalling: Dance hall moves show off symmetry and sex appeal
* Astrophysics: Blast from the past
* Physics: Einstein's E=mc2 is put to the test
* Planetary science: Martian plains not so wet?
* Review: Out of Africa challenge
* Evolution: Origin of tetrapod locomotion discovered
* And finally... Clocking off - reindeer obey different rhythms in the dark
* Mention of papers to be published at the same time with the same embargo
* Advance Online Publication
* Geographical listing of authors

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[1] Climate change: Aerosols have greater cooling effect than thought (pp1138-1141; N&V)

Aerosol particles generated by burning fuel have a much greater cooling
effect on the Earth than previous estimates have suggested, according to
research published in this week's Nature.

Fossil fuel burning produces the greenhouse gas carbon dioxide, a
significant cause of global warming. But it also releases haze particles
that scatter and absorb incoming sunlight, ultimately cooling our planet.
The balance of these two effects was poorly understood.

Nicolas Bellouin and colleagues have now made the most accurate measurement
so far of this cooling effect, using NASA's Terra and Aqua satellites, and
found that it is at the high end of estimates proposed by the
Intergovernmental Panel on Climate Change.

Concerns about the health impacts of aerosols have prompted efforts to
reduce their emission and improve air quality. A related News & Views
article from Jim Coakley accompanies this research.

Nicolas Bellouin (Met Office, Hadley Centre, Exeter, UK)
Tel: +44 1392 884 684, E-mail: [email protected]

Jim Coakley (Oregon State University, Corvallis, OR, USA)
Tel: +1 541 737 5686, E-mail: [email protected]

[5] Sexual signalling: Dance hall moves show off symmetry and sex appeal (pp1148-1150)

Most women would say that they like a man who can dance - and research
carried out on Jamaicans strutting their stuff now shows why. Men judged to
have superior moves also tend to have a greater degree of body symmetry, a
factor thought to be related to their potential as a quality mate.

Dancing is an important part of courtship in many societies, and William
Brown and his colleagues set out to discover whether dancing ability is
related to symmetry. They therefore used motion-capture cameras to record
dances performed by a range of males and females with different degrees of
body symmetry.

Women watching the recordings preferred the dances of symmetrical men, the
researchers report in this week's Nature. Likewise, men preferred dances
performed by more symmetrical females, although this effect was not as
marked, confirming the theory that women, who usually bear the majority of
the childcare burden, are more choosy when selecting a mate.

William Brown (Rutgers University, New Brunswick, NJ, USA)
Tel: +1 732 317 3389, E-mail: [email protected]

[6] Astrophysics: Blast from the past (pp1132-1134)

A team of astronomers has detected the 'echoes' of stars that exploded
several centuries ago. In this week's issue, Nicholas Suntzeff and
colleagues describe how they have seen light echoes of supernovae - old
stars that have collapsed and then exploded - in the small, nearby galaxy
called the Large Magellanic Cloud.

Supernovae are momentarily immensely bright, sometimes outshining all the
other stars in their host galaxy. The light that they produce can bounce off
nearby astrophysical objects such as dust clouds, just as shafts of sunlight
bounce off dust motes floating in a darkened room. Because of the huge
distances involved, such light echoes might still be glimmering in galaxies
hundreds of years after the supernova event.

Such echoes are relatively easy to see as concentric bright circles around
the recent supernova SN 1987A in the Large Magellanic Cloud. Suntzeff and
colleagues have been monitoring this galaxy closely since 2001, and they
have seen several other bright bands, which they interpret as light echoes
from three old supernovae. They work backwards from the echoes to identify
where the supernovae happened, and in two cases they are able to estimate
when they happened: four and six centuries ago, give or take a century or
two. They estimate that it may be possible to identify similar echoes from
supernovae as much as a thousand years old.

Sadly, however, it will be harder to spot echoes from the putative supernova
that some people have proposed as the origin of the Star of Bethlehem: if
this event ever happened at all, its repercussions will have grown too faint
in the intervening two millennia.

Nicholas Suntzeff (National Optical Astronomy Observatory, La Serena, Chile)
Tel: +56 51 205 200, E-mail: [email protected]

[7] Physics: Einstein's E=mc2 is put to the test (1096-1097)

Possibly the best-known equation in all of science is Einstein's famous
E=mc2, which expresses that mass and energy are interchangeable. If it were
just slightly incorrect, it would have enormous repercussions for modern
physics. No need to worry though. In this week's Nature, a new direct test
of the equation described in a Brief Communication confirms that E=mc2 is
true to within 0.00004%.

The equation predicts that a very small amount of mass is equivalent to a
very large amount of energy, because c2 is a very large number (c is the
speed of light). To test this, Simon Rainville and colleagues took careful
measurements of the change in mass that occurs for two different isotopes
when they have captured a neutron (not including the added mass of the
neutron), which should be equal to the energy of the gamma rays emitted as
the ions de-excite.

The team reduced the uncertainties of their measurements by using a
high-precision crystal-diffraction facility to determine the energy of the
gamma rays, and a special magnetic and electric field trap called a Penning
trap to determine the change in mass of the ions. Their result is 55 times
more accurate than previous efforts, a triumphant finale for the World Year
of Physics.

Simon Rainville (Université Laval, Quebec City, Canada)
Tel: +1 418 656 2131 ext.12511, E-mail: [email protected]

[10] & [11] Planetary science: Martian plains not so wet? (pp1123-1128 &

Minerals and rock patterns found by the Mars Exploration Rover Opportunity
have previously been interpreted as evidence for long-standing pools of
briny water on the red planet. But in this week's Nature, two research
papers question that interpretation and propose alternative explanations.
Thomas McCollom and Brian Hynek argue that the deposits seen by Opportunity
at an area of Mars called Meridiani Planum could in fact be formed from
volcanic ash, altered by very small amounts of acidic water and sulphur
dioxide, a volcanic gas.

Meanwhile, Paul Knauth and colleagues suggest that a ground-hugging,
turbulent surge of rock fragments, minerals and brine from a meteorite
impact could have produced the same layered features in the deposits studied
by Opportunity. A related News & Views article by Mark Bullock accompanies
this research.

Thomas McCollom (University of Colorado, Boulder, CO, USA)
Tel: +1 303 735 3072, E-mail: [email protected] - paper no: [10]

Paul Knauth (Arizona State University, Tempe, AZ, USA)
Tel: +1 480 965 2867, E-mail: [email protected] - paper no: [11]

Mark Bullock (Southwest Research Institute, Boulder, CO, USA)
Tel: +1 303 546 9027, E-mail: [email protected]

[12] Review: Out of Africa challenge (pp1099-1104)

The past decade has witnessed an explosion in the discovery of human
fossils, with the announcement of ten new species or genera and the
discovery of ancient hominids - such as the 1.8-million-year-old Homo
erectus-like hominids from Dmanisi in Georgia - outside the assumed African
homeland. This assumption of African origin is ripe for a challenge, say
Robin Dennell and Wil Roebroeks in a Review Article in this week's Nature.
Despite the spate of discoveries, we still know little about our ancestors,
and very much less about their patterns of origin and dispersal than we
think we do. Could humans of modern aspect have originated outside Africa
and migrated back? The time is ripe to think new thoughts about our origins.

Robin Dennell (University of Sheffield, UK)
Tel: +44 114 222 2000, E-mail: [email protected]

[13] Evolution: Origin of tetrapod locomotion discovered (pp1145-1147)

Today's four-limbed terrestrial animals, or tetrapods, are generally
'rear-wheel drive' - their hindlimbs provide much of the power for walking
or running. But a new analysis of a 360-year-old museum specimen suggests
that terrestrial walkers colonized the land by passing through a
'front-wheel drive' phase.

The first four-limbed vertebrates to crawl out of the water did so by
adopting a mode of locomotion similar to that of today's walking catfish,
which can shuffle across dry land, says Catherine Boisvert in this week's
issue of Nature. She arrived at her conclusion after studying a specimen of
a fishy ancestor of four-limbed vertebrates called Panderichthys, unearthed
in Latvia in 1972 and now housed at Tallinn University of Technology in

The pelvic fins of Panderichthys are much smaller than its pectoral fins,
which would therefore have borne much of the weight, allowing the creature
to shuffle along the ground or through shallow pools, Boisvert discovered.
Somewhere between this form and the later Acanthostega, which had more
powerful hindlimbs, these creatures must have shifted to a rear-wheel-drive
form of transport, she adds.

Catherine Boisvert (Uppsala University, Sweden)
Tel: +46 18 471 6223, E-mail: [email protected]

[14] And finally... Clocking off - reindeer obey different rhythms in the
dark (pp1095-1096)

Reindeer have a body clock that does not rely on a 24-hour light/dark cycle,
according to a Brief Communication published in this week's Nature. Living
at high latitudes means that daylight is continuous in summer, whereas
winter days are perpetually dark, so they need to use other cues to manage
their internal rhythms.

Karl-Arne Stokkan and colleagues studied two subspecies of reindeer for a
year, continuously recording their patterns of activity. The first group,
Rangifer tarandus platyrhynchus, lives in the high Arctic archipelago of
Svalbard, which lies approximately halfway between Greenland and Norway. The
second, R. t. tarandus, dwells in northern Norway. In these areas, organisms
experience a 24-hour day/night cycle for only a few weeks each year - in
spring and autumn. In summer and winter, the Sun neither rises nor sets, and
the team found that reindeer in these conditions lose circadian rhythmic
activity completely.

The authors suggest that many polar-dwelling species may have body clocks
that subside when not required. The ability to reduce the influence of
internal clocks is unusual, and the team's observation may open up new
avenues for research in the field of biological timing.

Karl-Arne Stokkan (University of Tromsø, Norway)
+47 776 44870, E-mail: [email protected]


[15] Extremely slow Drude relaxation of correlated electrons

[16] Anisotropy of Earth's D'' layer and stacking faults in the MgSiO3
post-perovskite phase (pp1142-1144)

[17] NMDA receptors are expressed in oligodendrocytes and activated in
ischaemia (pp1162-1166)

[18] NMDA receptors are expressed in developing oligodendrocyte processes
and mediate injury (pp1167-1171)

[19] WUSCHEL controls meristem function by direct regulation of
cytokinin-inducible response regulators (pp1172-1175)

[20] Double chromodomains cooperate to recognize the methylated histone
H3 tail (pp1181-1185)


***These papers will be published electronically on Nature's website on 21
December 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 them on this release to avoid multiple mailings they will not
appear in print on 22 December, but at a later date.***

[21] Gamma-band synchronization in visual cortex predicts speed of change
DOI: 10.1038/nature04258

[22] NMDA receptors mediate calcium accumulation in myelin during
chemical ischaemia
DOI: 10.1038/nature04474

[23] Origins of extrinsic variability in eukaryotic gene expression
DOI: 10.1038/nature04281


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.

Parkville: 4

Innsbruck: 3

Sao Paulo: 3, 4

Calgary: 22
Hamilton: 6
Ottawa: 22
Quebec City: 7

La Serena: 6
Santiago: 6

Grenoble: 7, 8
Orsay: 4
Paris: 3, 4

Goettingen: 3, 4
Karlsruhe: 4
Mainz: 15
Marburg: 3
Stuttgart: 15
Tuebingen: 19

New Delhi: 8

Chosi: 2
Fuchu: 2
Fukuoka: 2
Hiroshima: 2
Ikoma: 2
Kyoto: 2
Nagoya: 2, 3
Nishinomiya: 2
Noda: 2
Sendai: 2, 3
Tokyo: 2, 3, 4
Tsukuba: 2, 3,4

Groningen: 14
Leiden: 12
Nijmegen: 21

Auckland: 9
Palmerston North: 9

Oslo: 17
Tromso: 14

Madrid: 3, 4
Salamanca: 3

Uppsala: 13

Lausanne: 3
Lugano: 16
Zurich: 16

Exeter: 1
Glasgow: 4
Hinxton: 3, 4
Leicester: 18
Liverpool: 4
London: 17
Manchester: 2, 3, 4
Norwich: 4
NottinghamL 2, 3, 4
Oxford: 7
Sheffield: 3, 12

Tempe: 11
La Jolla: 23
Livermore: 6
Mountain View: 4
Stanford: 4
Boulder: 10
District of Columbia
Washington: 2, 3, 4
Tallahassee: 7
Athens: 4
Moscow: 3, 4
Argonne: 20
Lexington: 3, 4
New Orleans: 2, 3
Bethesda: 21
Gaithersburg: 7
Rockville: 2, 3, 4
Boston: 20, 23
Cambridge: 3, 4, 6, 7, 21
Lincoln: 4
New Jersey
New Brunswick: 5
Princeton: 1
New Mexico
Los Alamos: 11
New York
Cold Spring Harbor: 21
North Carolina
Chapel Hill: 19
Cleveland: 22
Columbus: 6
Beaverton: 4, 9
Eugene: 4
College Station: 4
Houston: 3
Charlottesville: 20
Madison: 3, 4
Seattle: 5, 6

For North America and Canada
Katie McGoldrick, Nature Washington
Tel: +1 202 737 2355; E-mail: [email protected]
<mailto:[email protected]>

For Japan, Korea, China, Singapore and Taiwan
Rinoko Asami, Nature Tokyo
Tel: +81 3 3267 8751; E-mail: [email protected]
<mailto:[email protected]>

For the UK/Europe/other countries not listed above
Katharine Mansell, Nature London
Tel: +44 20 7843 4658; E-mail: [email protected]

Sophie Hebden, Nature London
Tel: +44 20 7843 4502; E-mail: [email protected]

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