The signs of life; Primate police; Dance of the dollars sheds light on epidemiology; Metals between order and chaos; Small planets are far out; Plants and animals play by different metabolic rules; Well-travelled snails hitch a ride around the globe

Summaries of newsworthy papers from Nature, Vol.439 No.7075 Dated 26 January 2006

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VOL.439 NO.7075 DATED 26 JANUARY 2006

This press release contains:
* Summaries of newsworthy papers:
* Earth science: The signs of life
* Animal behaviour: Primate police
* Complex systems: Dance of the dollars sheds light on epidemiology
* Materials science: Metals between order and chaos
* Astronomy: Small planets are far out
* Biological scaling: Plants and animals play by different metabolic rules
* And finally...Well-travelled snails hitch a ride around the globe
* Geographical listing of authors

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[1] Earth science: The signs of life (pp411-418)

Life on Earth sculpts the landscape around it in many different ways, but is
there a topographic signature of life? According to a Review article in this
week's Nature, we cannot yet point to a landform that uniquely reflects the
presence of life.

William E. Dietrich and J. Taylor Perron discuss the ways that biota affect
the processes changing the landscape such as soil erosion, weathering and
climate change. Yet in all cases, an abiotic (or lifeless) process can
produce similar shapes and patterns on Earth.
In the absence of life, however, Earth would still look very different, but
the difference would lie in the frequency distribution of certain landform
properties. Dietrich and Perron also suggest that a topographic signature of
life may yet be found at the scale of a metre or less.

CONTACT
William E. Dietrich (University of California, Berkeley, CA, USA)
Tel: +1 510 642 2633; Email: [email protected]

[2] Animal behaviour: Primate police (pp426-429)

Policing is essential for achieving social stability in primates, reports a
study in this week's Nature. The research on a captive group of pigtailed
macaques (Macaca nemestrina) shows that conflict management has a positive
effect on social resource networks, promoting integrated grooming and play
and reducing the impact of chronic perturbations, which can lead to group
fragmentation.

Jessica Flack and colleagues studied the behavioural processes of niche
construction by conducting a series of 'knockout' experiments to determine
the effect of removing key policing individuals on four social networks:
grooming, play, contact-sitting and proximity. They found that individuals
have significantly more play and grooming partners in the presence of
policing and are more willing to integrate. In the absence of policing,
individuals are more likely to form cliques and tend to sit in areas away
from others, in order to avoid conflict.

Policing gives rise to larger, more structured social networks. Such
structures provide important behavioural resources, which influence infant
survivorship, emergence and spread of cooperative behaviour, social learning
and cultural traditions. The study has implications for how animal social
organizations are built and presents a new experimental design for knockout
studies.

CONTACT
Jessica Flack (Santa Fe Institute, NM, USA)
Tel: +1 505 946 2711; E-mail: [email protected]

[4] Complex systems: Dance of the dollars sheds light on epidemiology
(pp462-465)

An unusual approach to understanding the geographical dispersion of humans
is reported in this week's Nature.

Dirk Brockmann and colleagues analysed the trajectories of nearly half a
million US dollar bills recorded in the online US bill-tracking system
www.wheresgeorge.com. On the basis of their analyses, they concluded
that the dispersal of bank notes - and therefore human travelling behaviour
- can be described by a process of many small random steps with occasional
large jumps; as well as long waiting times between displacements.

These findings may have important consequences for modelling the spread of
human diseases, for which a precise knowledge of dynamical and statistical
properties of human travel is of fundamental importance. The behavioural
pattern described by the authors means that modellers cannot simply assume
that humans disperse diffusively.

CONTACT
Dirk Brockmann (Max-Planck-Institute for Dynamics and Self-Organization,
Göttingen, Germany)
Tel: +49 551 5176 411; E-mail: [email protected]

[5] Materials science: Metals between order and chaos (pp419-425; N&V)

A metallic glass might sound like an oxymoron, but such things do exist and
are potentially useful materials. In this week's Nature, Hong Wei Sheng and
colleagues show how the packing of atoms in metallic glasses maintains a
delicate balance between crystal-like and random structures.

Normal metals are crystalline: their atoms are arranged in regular, orderly
arrays, like oranges stacked on a greengrocer's stall. In window glass, on
the other hand, the component atoms are disorderly, jumbled together like an
unruly yet virtually static crowd. Metallic glasses also have a disordered
arrangement of atoms - but they are neither ductile, like ordinary metals,
nor brittle, like window glass. They are tough and springy, which is why
they are being explored for uses ranging from golf-club heads to armour
plating.

Although there is no 'long-range' order in metallic glasses they do have
some degree of regularity over shorter scales. Not only are each atom's
immediate neighbours arranged rather similarly to those in a crystal, but
even the next-nearest neighbours and the ones beyond may have some
non-randomness, some predictability, in their positions.

Several different theoretical models have been proposed for the structure of
metallic glasses, but only now do the experiments and computer-modelling
studies of Sheng and colleagues subject them to scrutiny. The researchers
show that groups of atoms tend to form clusters with geometric, polyhedral
shapes in the short range; they also propose some fundamentally new packing
schemes which constitute medium-range ordering, up to length scales of
several ångströms.

CONTACT
Hong Wei Sheng (Johns Hopkins University, Baltimore, MD, USA)
Tel: +1 410 516 8944; E-mail: [email protected] <mailto:[email protected]>

Alain Reza Yavari (Institut National Polytechnique de Grenoble, France)
Tel: +33 4 7644 6863; E-mail: [email protected]

[6] Astronomy: Small planets are far out (pp437-440; N&V)

A planet five and a half times more massive than the Earth has been
discovered in orbit around a star 28,000 light years away. This is the first
relatively small planet that is not huddled very close to its parent star.
The new planet, named OGLE-2005-BLG-390Lb, is described in Nature this week.
It orbits its sun at more than two and a half times the distance between the
Earth and our own Sun (1 astronomical unit, or au).

Most extrasolar planets are detected by the wobble that they induce in their
parent stars' orbits (around the common centre of mass of the stellar
system). But such planets must generally be either big or close to their sun
in order to produce a wobble big enough to be detected. Jean-Philippe
Beaulieu and co-workers have used a different approach. They are part of an
international collaboration, which uses several telescopes worldwide to look
for extrasolar planets. In microlensing, the light from a distant star is
bent and focused by the gravitational field of a nearer star. If a planet
orbits the lensing star, this can lead to additional magnification of the
background star, allowing the planet's mass and orbit to be calculated.
Such an event was detected in June 2005 and at 5.5 times the Earth's mass,
the new planet is much smaller than Neptune. Previously, extrasolar planets
smaller than Neptune have not been found further from their parent star than
0.15 au.

Models suggest that such modest-sized planets will typically have orbits of
1-10 au. So this first detection of such a world beyond 0.15 au comes as
some relief to researchers trying to understand how planets form.

CONTACT
Jean-Philippe Beaulieu (Institut d'Astrophysique de Paris, Paris, France)
Tel: +33 1 4432 8119; E-mail: [email protected]

Didier D Queloz (Observatoire de Geneve, Switzerland)
Tel: +41 22 379 2477; E-mail: [email protected]

[7] Biological scaling: Plants and animals play by different metabolic rules
(pp457-461; N&V)

For decades biologists have hoped that all living organisms might follow a
universal rule for how metabolic rate changes with size. But a new
comprehensive analysis of metabolism in 43 different plant species shows
that plants follow a different law to that governing animals.

In the animal kingdom, metabolic rate increases with body mass, but not
linearly. Instead, it follows a more complicated 'logarithmic' relationship
that arises because of the branching pattern of the blood vessels that
distribute oxygen and metabolites around the body. So elephants use more
energy than mice, but not as much as you might expect based on body size
alone. This means that larger animals generally tend to lumber around while
smaller creatures live more hectic lives. Experts had hoped that plant
species might follow a similar law. But instead, Peter Reich and co-workers
report in this week's Nature that metabolic rates in plants, unlike animals,
do follow a linear relationship. Having surveyed some 500 individual plants,
they find that metabolic rate scales with plant mass or, more accurately,
with the total amount of nitrogen that the plant contains. "Their findings
question our understanding of how plant metabolism is organized," comments
Lars Hedin in an accompanying News and Views article.

CONTACT
Peter Reich (University of Minnesota, MN, USA)
Tel: +1 612 624 4270; E-mail: [email protected]

Lars Hedin (Princeton University, Princeton, NJ, USA)
Tel: +1 609 558 9096 or +1 609 258 7893; Email: [email protected]

[8] And finally...Well-travelled snails hitch a ride around the globe (p409)

A group of land-snail species have been shown to belong to one big family,
despite living on far-flung islands some 9,000 kilometres apart. The
discovery, made by comparing their DNA sequences, raises the intriguing
question of how they accomplished their extensive ocean-going journeys -
with migratory birds being the leading contenders for ferrying them around
the globe.

Snails of the genus Balea are found throughout Europe and the Azores, a
remote group of islands in the middle of the North Atlantic. Similar snails
are also found on the Tristan da Cunha archipelago in the South Atlantic,
but naturalists had assigned them to a different species because of their
sheer distance from the Northern Hemisphere species.

But, by comparing the genetic sequences of these snails, researchers led by
Richard Preece have discovered that all of the more than 20 species of Balea
arose from a single, relatively recent common ancestor. As the researchers
explain in a Brief Communication in this week's Nature, this means that they
represent a single genus that has spread over incredible swathes of open
ocean. This supports the possibility that the molluscs may have been
transported by birds - a phenomenon that fascinated Charles Darwin during
his studies on the origin of species.

CONTACT
Richard Preece (University of Cambridge, Cambridge, UK)
Tel: +44 1223 36666; Email: [email protected]

ALSO IN THIS ISSUE...

[9] Epigenetic silencers and Notch collaborate to promote malignant
tumours by Rb silencing (pp430-436)

[10] Laser acceleration of quasi-monoenergetic MeV ion beams (pp441-444)

[11] Laser-plasma acceleration of quasi-monoenergetic protons from
microstructured targets (pp445-448)

[12] Amplification of chirality in two-dimensional enantiomorphous
lattices (pp449-452)

[13] A climatologically significant aerosol longwave indirect effect in
the Arctic (pp453-456)

[14] Pregnenolone stabilizes microtubules and promotes zebrafish
embryonic cell movement (pp480-483)

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.

AUSTRALIA
Hobart: 6
Perth: 6
Weston Creek: 6

AUSTRIA
Vienna: 6

CHILE
Concepcion: 6
Santiago: 6

DENMARK
Kobenhavn: 6

FRANCE
Gif-sur-Yvette: 6
Paris: 6
Toulouse: 6

GERMANY
Jena: 11
Garching: 10
Gottingen: 4
Heidelberg: 6
Munich: 10
Potsdam: 6

JAPAN
Kyoto: 11
Nagano: 6
Nagoya: 6
Tokyo: 3
Saitama: 3
Sapporo: 3

THE NETHERLANDS
Leiden: 8

NEW ZEALAND
Auckland: 6
Christchurch: 6
Wellington: 6

POLAND
Kornik: 7
Warsaw: 6

RUSSIA
Moscow: 11

SOUTH AFRICA
Cape Town: 6
Bloemfontein: 6

SPAIN
Alicante: 9
Puerto Real: 9

SWEDEN
Huddinge: 3

SWITZERLAND
Dubendorf: 11

TAIWAN
Taipei: 14

UK
Belfast: 6
Birkenhead: 6
Cambridge: 8
Glasgow: 11
Macclesfield: 6
Reading: 11
St Andrews: 6

USA
California
Berkeley: 1
David: 3
La Jolla: 13
Livermore: 6
Santa Barbara: 4
Florida
Gainesville: 6
Georgia
Atlanta: 2
Indiana
Notre Dame: 6
Maryland
Baltimore: 5, 6
Gaithersberg: 5
Minnesota
St Paul: 7
Nevada
Reno: 10
New Jersey
Princeton: 6
New Mexico
Los Alamos: 10
Santa Fe: 2
New York
Upton: 13
Pennsylvania
Swarthmore: 7
Tennessee
Oak Ridge: 5
Texas
College Station: 7
Fort Davis: 6
Wisconsin
Madison: 3

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

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

For the UK/Europe/other countries not listed above
Ruth Francis, Nature London
Tel: +44 20 7843 4562; E-mail [email protected]

Zoe Corbyn, Nature London
Tel: +44 20 7843 4658; E-mail: [email protected]

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Published: 25 Jan 2006

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