Water supply and human health impacts of global warming, Capturing the danger of superspreaders; From genome to 'venome'; Left-handers take the field; Climate change and regional response; Regional US commitment to cutting emission; Hunger guides the way

Summaries of newsworthy papers from Nature. Vol.438 No.7066 Dated 17 November 2005 including Optical telecommunications: Meaning from chaos and Development: A starring role for SCL in astrocytes

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This press release is copyright Nature. VOL.438 NO.7066 DATED 17 NOVEMBER 2005

This press release contains:
* Summaries of newsworthy papers:
* Climate change: Water supply and human health impacts of global warming
* Infectious disease: Capturing the danger of superspreaders
* Evolution: From genome to 'venome'
* Optical telecommunications: Meaning from chaos
* Materials: Left-handers take the field
* Development: A starring role for SCL in astrocytes
* Commentaries: Climate change and regional response
* Environmental policy: Regional US commitment to cutting emission
* And finally... Hunger guides the way
* Mention of papers to be published at the same time with the same embargo
* Geographical listing of authors

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[1], [2] & [3] Climate change: Water supply and human health impacts of
global warming (pp303-309; pp310-317;pp347-350)

The regional effects of climate change are explored by three articles in
this week's Nature.
In a Review article, Tim Barnett and colleagues evaluate the effect of
surface warming trends on regional hydrology, particularly in
snowmelt-dominated environments. They suggest that in a warmer world, less
snowfall in winter and snow melting earlier in the year means that the peak
river run-off is shifted to winter and early spring, away from summer and
autumn when water demand is highest. If storage capacities are insufficient,
much of the winter run-off is lost into the ocean. The reduction in glaciers
and snow-pack are likely to have severe consequences for the freshwater
supply of one-sixth of the Earth's population.
Jonathan A. Patz and colleagues' Review addresses the impact of climate
change on human health. They consider the available evidence and suggest
that climate warming may already have contributed to ill health and
thousands of premature deaths across the world, and is likely to have
serious implications in terms of future human health. Recent research
suggests that some regions are particularly at risk: temperate latitudes are
likely to experience disproportionately large temperature increases. Areas
where the climate is dominated by the El Niño/Southern Oscillation are
already vulnerable to climate-related health impacts and may become more so,
and with growing urbanization the urban heat-island effect is projected to
increase health risks.
Chris Milly and colleagues present research on the effect of climate change
on streamflow and trends in water availability and find that an ensemble of
12 current climate models accurately accounts for twentieth-century changes.
The same models project potentially crucial regional effects on streamflow
in the future, threatening the availability of fresh water in many regions
of the world by the year 2050.
CONTACT
Tim Barnett (Scripps Institute of Oceanography, University of California at
San Diego, La Jolla, CA, USA) paper no: [1]
Tel: +1 858 534 3223, E-mail: [email protected]

Jonathan A. Patz (University of Wisconsin-Madison, WI, USA) paper no: [2]
Tel: +1 608 262 4775, E-mail: [email protected]

Chris Milly (US Geological Survey, GFDL/NOAA, Princeton, NJ, USA) paper no:
[3]
Tel: +1 609 452 6507, E-mail: [email protected]

[4] Infectious disease: Capturing the danger of superspreaders (pp355-359;
N&V)

From Typhoid Mary to SARS, it has long been known that some people spread
disease more than others. But for many diseases transmitted through casual
contact, scientists have had to rely on population averages to estimate a
disease's potential to spread. Some analysts have used Ro, defined as the
mean number of infections caused by an infected individual in a susceptible
population, to calculate the course of an epidemic.
Now, in a paper appearing in this week's Nature, James Lloyd-Smith
and his colleagues describe the need for a more sophisticated view of how
epidemics emerge. They take a close look at eight human diseases and show
how some, such as SARS (and perhaps avian flu), show a strong tendency
towards 'superspreading events', in which the number of people that one
individual infects is highly variable. Other diseases analysed, including
smallpox and pneumonic plague (two potential bioterrorism agents) show
steadier spreading.
"[The authors] show that individual-specific strategies are more
likely to exterminate an emerging disease than population-wide
interventions, because the former increase heterogeneity in infectiousness,"
write Alison Galvani and Robert May in a related News and Views piece.
CONTACT
James Lloyd-Smith (University of California, Berkeley, CA, USA)
Tel: +1 510 643 1227, E-mail: [email protected]

Wayne Getz, co-author (University of California, Berkeley, CA, USA)
Tel: +1 510 642 8745, E-mail: [email protected]

Alison Galvani (Yale University School of Medicine, New Haven, CT, USA)
Tel: +1 203 785 2922, E-mail: [email protected]

Robert May (University of Oxford, UK)
E-mail: [email protected]

[5] Evolution: From genome to 'venome' (DOI: 10.1038/nature04328)

***This paper will be published electronically on Nature's website on 16
November 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 November, but at a later date.***

Conventional wisdom has it that, among reptiles, venom delivery is something
that is mainly associated with snakes, and underlies the dramatic success of
this group, with 2,500 out of 3,000 snake species being venomous. In
contrast, venom delivery is found in just two species of lizard, in which it
is believed to have evolved independently from snakes.
A new study by Bryan Fry and colleagues, to be published online by Nature
this week, reveals that venom delivery among lizards is in fact much more
widespread. The researchers show that two additional major lineages of
lizards - varanids and iguanians - also produce venom toxins, and that these
lizards even possess various forms of venom glands. The new work suggests
that the side-effects of nasty lizard bites may actually be due to venom
rather than incidental bacterial infection, and that snakes and lizards are
much more closely related than has been previously thought - with snakes
evolving from relatively advanced lizards, rather than representing a
separate evolutionary radiation.

CONTACT
Bryan Fry (University of Melbourne, Australia)
Tel: +61 3 8344 7753, E-mail: [email protected]

[6] Optical telecommunications: Meaning from chaos (pp343-346; N&V)

Transmitting light-based signals by embedding them in chaos doesn't sound
like a particularly good idea. But in this week's issue, Claudio Mirasso and
co-workers show otherwise. They have demonstrated that it is possible to
send such a signal over a distance of 120 km using a commercial fibre-optic
telecommunication network in the metropolitan area of Athens, Greece.
There are several benefits of sending information encoded in chaotic
signals. For one thing, the chaos serves as a good encryption system: at
face value, the signal looks like pure noise, and it's only when the
receiver generates its own chaotic output signal, which can be synchronized
with that of the transmitter, that the chaos can be removed to recover the
true signal. But also, chaotic 'carrier' signals are broadband signals -
they have a wide range of frequencies - which makes them more robust in the
face of interference.
The basic idea is that a chaotic light signal is generated by a transmitting
laser, and the receiver contains a second laser that can be induced by a
feedback circuit to produce a chaotic output synchronized with that of the
transmitter. The information-laden optical signal is mixed in with the
chaotic signal in the transmitter, but can be decoded by subtracting the
synchronized chaos of the receiver. This process had been demonstrated
previously over very short distances in the laboratory, but Mirasso and
colleagues have now proved that it will work in the real world. A related
News & Views article by Rajarshi Roy accompanies this research.

CONTACT
Claudio Mirasso (Universitat de les Illes Balears, Palma de Mallorca, Spain)
Tel: +34 971 172 783, E-mail: [email protected]

Rajarshi Roy (University of Maryland, College Park, MD, USA)
Tel: +1 301 405 1636, E-mail: [email protected]

[7] Materials: Left-handers take the field (pp335-338; N&V)

Scientists have made a material with unusual optical properties that could
be the precursor of a 'perfect lens', focusing images to show features
smaller than the wavelength of light itself.
This relies on so-called 'left-handed' materials that allow negative
refraction, where electromagnetic waves bend in the opposite direction to
normal materials. Although this has been achieved for microwave frequencies,
it is still out of reach for visible light.
In this week's Nature, Alexander Grigorenko and colleagues show that
negative permeability - a necessary condition for achieving a left-handed
material - is possible for visible light waves. Permeability describes how
the material responds to the magnetic field of the light wave as it passes
through, and a material's refractive index is partly determined by its
permeability.
The scientists covered a small glass plate with tiny gold pillars, each
about 100 nanometres high. They found that as light interacts with the
structures, it changes their magnetic field and reflective properties,
unlike a normal piece of gold.
"This is in itself a significant step towards a perfect lens, and other
novel optical components for visible frequencies," comments Roy Sambles in a
related News and Views article.

CONTACT
Alexander Grigorenko (Manchester University, UK)
Tel: +44 161 275 4097, E-mail: [email protected]

Roy Sambles (University of Exeter, UK)
Tel: +44 1392 264103, E-mail: [email protected]

[8] Development: A starring role for SCL in astrocytes (pp360-363)

As the most abundant glial cells, which make up the brain together with
nerve cells, astrocytes have traditionally been viewed as serving structural
and supportive roles. Scientists have recognized that astrocytes help to
form the blood-brain barrier and that some possess stem-cell properties. But
surprisingly little is known about what controls the development of these
cells.

Now, David Rowitch and colleagues provide a vital clue to this mystery: in a
paper appearing in this week's Nature, they describe how a protein called
SCL instructs immature neural stem cells to become astrocytes. The findings
could shed light on the role these cells play in neurological diseases such
as brain cancer, amyotrophic lateral sclerosis (ALS) and Alzheimer's
disease.

CONTACT
David Rowitch (Dana-Farber Cancer Institute, Boston, MA, USA)
Tel: +1 617 632 4201, E-mail: [email protected]

Commentaries: Climate change and regional response (pp283-256 & p286)

As climate change grows as a threat, the responses of different countries
are subject to intense scrutiny. In a Commentary in this week's Nature, two
US government scientists describe the hurricanes of 2005 as a wake-up call
to those concerned with minimizing loss of life and property from such
disasters. In an accompanying Commentary, scientists and engineers from the
Netherlands explain how their country is responding to its high risk of
flooding with dykes built to the highest standards in the world.
'The prospect of global climate change caused by greenhouse-gas
emissions means that key climate and hydrological variables will change',
write Pavel Kabat and colleagues in their Commentary. They investigate how
infrastructure is being used to reduce risks, and ask why it is accepted by
both the Dutch government and the people that millions of Euros are being
spent on 'climate proofing' the country while elsewhere in the world this is
not happening.
Aristides Patrinos and Anjuli Bamzai argue that the path between
climate science and policy is not always linear. They suggest that while
societies need robust infrastructures to deal with extreme weather
conditions, when developing policy responses to regional climate change it
is essential to consider the vulnerability of the communities affected. This
is relevant not just to continents like Africa, where extreme poverty and
natural disasters, such as drought, take millions of lives; over the past 30
years, US coastal development has quadrupled, placing 45 million people in
precarious situations along hurricane-prone coastlines.

CONTACT
Pavel Kabat (Wageningen University, The Netherlands)
Tel: +31 317 474314, E-mail: [email protected]

Aristides Patrinos (US Department of Energy, Washington DC, USA)
Please note: we are sourcing a media contact for this article. Please check
the press site for updates.

[9] Environmental policy: Regional US commitment to cutting emissions (pp
301-302)

The United States does not participate in the Kyoto protocol, even though
the country produces 24% of worldwide greenhouse-gas emissions. However, in
a Brief Communication in this week's Nature, Brendan Fisher and Robert
Costanza find that about one-quarter of the US population lives in states,
counties or cities that have adopted climate-change policies similar to
Kyoto. Including those regions classified as 'probable' and 'possible'
adopters, which have pledged to reduce emissions, more than one-third of the
US population lives in such areas. Together, these regions contribute up to
half of the US gross domestic product.
Although these numbers look promising, the authors caution that "compliance
will be a challenge even for current adopters, who have on average increased
their carbon dioxide emissions by 14% since 1990." There are no mechanisms
to enforce such initiatives, they add. However, the local nature of these
initiatives could make it possible to develop adaptable, site-specific plans
for reducing greenhouse-gas emissions, the authors point out.

CONTACT
Brendan Fisher (University of Vermont, Burlington, VT, USA)
Tel: +1 802 656 2900, E-mail: [email protected]

[10] And finally... Hunger guides the way (p302)

Ants use visual cues to find their way home when fed, and to find food when
unfed, a Brief Communication in this week's Nature shows.
Thomas Collett and colleagues trained ants by letting them walk alongside a
black wall from a start pot to a drop of sucrose on a glass slide. This way,
the ants learned that the wall would be on their left when walking towards
the sucrose, but on their right when walking home.
In a later experiment, trained ants were deposited midway along the wall.
Unfed ants walked in the direction towards the food with the wall on their
left, whereas fed ants walked in the opposite direction. Even rotating the
wall didn't change their preference for certain directions relative to the
walls.
Ants resemble honeybees in that their feeding state determines whether they
move towards food or home, the authors say. But they differ from honeybees
in that they don't use a celestial compass to guide them, but rely on visual
cues instead.

CONTACT
Thomas Collett (University of Sussex, Brighton, UK)
Tel: +44 1273 678507, E-mail: [email protected]

Rob Harris, co-author (University of Sussex, Brighton, UK)
Tel: +44 1273 872811, E-mail: [email protected]

Paul Graham, co-author (University of Sussex, Brighton, UK)
Tel: +44 1273 872943, E-mail: [email protected]

Natalie Hempel, co-author (University of Sussex, Brighton, UK)
Tel: +44 1273 872811

ALSO IN THIS ISSUE...

[11] Structure of the E. coli protein-conducting channel bound to a
translating ribosome (pp318-324; N&V)

[12] A light-sensing knot revealed by the structure of the
chromophore-binding domain of phytochrome (pp325-331)

[13] The formation of stars by gravitational collapse rather than
competitive accretion (pp332-334)

[14] Spin-torque diode effect in magnetic tunnel junctions (pp339-342)

[15] Palaeoanatomy and biological affinities of a Cambrian deuterostome
(Stylophora) (pp351-354)

[16] Control of B-cell responses by Toll-like receptors (pp364-368)

[17] A histone H3 methyltransferase controls epigenetic events required
for meiotic prophase (pp374-378)

[18] Chromatin remodelling at a DNA double-strand break site in
Saccharomyces cerevisiae (pp379-383)

[19] Force production by disassembling microtubules (pp384-388)

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
Clayton: 5
Melbourne: 5
Parkville: 5

BELGIUM
Brussells: 6

FRANCE
Besanc: 6
Paris: 5
Villeneuve d'Ascq: 15

GERMANY
Darmstadt: 6

GREECE
Athens: 6

ISRAEL
Tel Aviv: 5

ITALY
Pavia: 6

JAPAN
Tsukuba: 14
Chiba: 8
Fuchu: 14
Izumi: 17
Kawagushi: 14
Saitama: 17
Sendai: 17
Toyonaka: 14

THE NETHERLANDS
Leiden: 5

RUSSIA
Chernogolovka: 7
Moscow: 19
Pushchino: 19

SPAIN
Palma de Mallorca: 6
Santander: 6
Terrassa: 6

SWITZERLAND
Geneva: 2, 5
Zurich: 11

UNITED KINGDOM
Birmingham: 7
Brighton: 10
Cambridge: 17
Hull: 4
London: 15
Manchester: 7
Bangor: 7

UNITED STATES OF AMERICA
California
Berkeley: 4, 13
La Jolla: 1, 11
Livermore: 13
Stanford: 14
Colorado
Boulder: 19
Connecticut
New Haven: 10
Illinois
Argonne: 12
Massachusetts
Boston: 8
New Jersey
Princeton: 3, 13
New Mexico
Albuquerque: 18
New York
Albany: 11
North Dakota
Bismarck: 3
Pennsylvania
University Park: 5
Vermont
Burlington: 9
Virginia
Williamsburg: 4
Washington
Seattle: 1
Wisconsin
Madison: 2, 12

PRESS CONTACTS...
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
Ruth Francis, Nature London
Tel: +44 20 7843 4562; E-mail [email protected]
<mailto:[email protected]>

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

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Published: 16 Nov 2005

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