[1] Seismology: And now the earthquake forecast for today... (pp328-331; N&V)
Californians could soon be using the Internet to check the daily earthquake forecast as well as the weather. A newly devised model can calculate the probability that a given spot will be hit by severe shaking over the ensuing 24 hours.
The model, created by Matthew Gerstenberger and his colleagues and unveiled in this week's Nature, begins by assessing the 'background' earthquake risk, from a knowledge of the overall behaviour of California's fault lines, such as the San Andreas fault. It then factors in the anticipated knock-on effects of any medium or large earthquakes that have occurred in the region in the past few years.
The final result is a map of overall earthquake risk for any given location in California, which, for maximum usefulness, is expressed as the probability that a place will experience sufficient shaking to crack plaster or break windows. The United States Geological Survey will continually update these 24-hour forecasts on the web (http://pasadena.wr.usgs.gov/step/)*
"It remains to be seen in what ways, besides the educational value, such short-term (and generally low) probabilities will be used by the public and by emergency services," writes Duncan Agnew in an accompanying News and Views article. He adds that he hopes to see the same method used in the world's other earthquake-prone regions.
CONTACT
Matthew C. Gerstenberger, (US Geological Survey, Pasadena, CA, USA)
Tel: +1 626 583 7238; E-mail: [email protected]
Duncan Agnew (Scripps Institution of Oceanography, University of California, San Diego (UCSD), La Jolla, CA, USA)
Tel: +1 858 534 2590; E-mail: [email protected]
*Please note: The content of this site is the sole responsibility of the USGS
[2] Seismology: Satellite study reveals dynamics of shallow quakes (pp300-307)
In other earthquake news, researchers studying the earthquake that devastated the Iranian town of Bam on 26 December 2003 have shown that, although the majority of the slip on the fault occurred at relatively shallow depths, no slip at all occurred at the surface.
Yuri Fialko and his colleagues used data from the European Space Agency's Envisat satellite to image the earthquake zone before and after the quake, which allowed them to build up a picture of exactly how the earth moved. They calculate that most of the seismic energy was released 4-5 kilometres underground - which is relatively shallow for an earthquake - yet the rupture did not break the surface.
The authors, reporting in this week's Nature, were able to trace displacements continuously across the fault, to provide the first unambiguous evidence of no slip occurring near the Earth's surface during a shallow earthquake. This demonstrates that such 'shallow slip deficit', postulated from earlier studies, is real, and the researchers suggest that it is caused by a distributed failure of the shallow crust in the time period between earthquakes.
CONTACT
Yuri Fialko (University of California, San Diego (UCSD), La Jolla, CA, USA)
Tel: +1 858 822 5028; E-mail: [email protected]
[3] Relics: Oldest modern human bones in Europe (pp332-335)
A collection of bones from Mladec in the Czech Republic is now confirmed as the earliest evidence for modern humans in Europe, according to research in this week's Nature. The research ends a debate over their chronology that has been ongoing since their discovery.
The Mladec site is significant both in human evolutionary and archaeological terms. With recent dating of other early human remains across Europe-some showing that supposedly old bones are in fact more recent (see Nature 430, 198-201; 2004)-dating the Mladec remains is pivotal to our understanding of how and when humans arrived in Europe, and how they interacted with the resident Neanderthals.
Several attempts have been made to date the fossil assemblage accurately, by dating the surrounding soil and animal remains, but so far all of them have failed. Using a technique called accelerator mass spectrometry (AMS) radiocarbon dating, Eva Wild, Maria Teschler-Nicola and colleagues now show that the remains are about 31,000 radiocarbon years old*. This ties in with dates from other sites in Europe that have yielded artefacts characteristic of the Aurignacian** tradition, the characteristic style of tools and art works associated with early modern humans.
CONTACT
Eva M. Wild, (Vienna Environmental Research Accelerator (VERA) Laboratory, The University of Vienna, Austria)
Tel: +43 1 4277 51704; E-mail: [email protected]
Maria Teschler-Nicola (Natural History Museum of Vienna, Austria)
Tel: +43 222 521 77 239; E-mail: [email protected]
Important notes for editors:
*Radiocarbon years and calendar years are not necessarily the same things. They tend to diverge and converge at different periods in prehistory, consistent with the varying atmospheric abundance in the isotope carbon 14 on which the technique is based. The discrepancy is significant during the period concerned, and calibrating radiocarbon and calendar years for the period in question is a matter of ongoing research.
**During the Upper Palaeolithic period (35,000 BC to 8,000 BC), a number of human cultures such as the Aurignacian rose and developed in the Old World.
[4] Cancer research: Testicular cancer gene identified (pp360-364)
In this week's Nature, scientists identify a gene that causes testicular cancer in mice. A huge increase in testicular cancer incidence from 5% to 94% was described in a mouse strain more than 30 years ago, but it has taken until now for the identity of the gene itself to be discovered.
Testicular cancer is the most common type of cancer among males between 15 to 30 years of age, and its incidence is increasing in western countries. The study reveals that the Ter mutation occurs in a gene called deadend which involved in normal testicular development, but, according to Angabin Matin and colleagues, Ter mutations can increase testicular tumour incidence dramatically in mice. These results suggest that the Ter mutation may adversely affect essential aspects of primordial germ cell biology, and the authors explain that the work will have important implications for our understanding of the genetic control of testicular germ cell tumours.
CONTACT
Angabin Matin, (University of Texas, Houston, TX, USA)
Tel: +1 713 7945250; E-mail: [email protected]
[5] Space: Radios listen in to solve cosmic puzzle (pp313-316)
The Earth is constantly bombarded with high-energy particles from space, called cosmic rays. They come from various astrophysical sources, but the origin of the highest-energy cosmic rays is still a mystery. These ultra-high-energy cosmic rays (UHECRs) seem to come from beyond our Galaxy, yet theory suggests that such particles ought to be slowed down and eventually absorbed before they can travel very far through space.
To solve this puzzle, we first need to know what they are - they could be atomic nuclei, or protons, or ultra-light particles called neutrinos, or even gamma-rays. Heino Falcke and an international team show in this week's Nature that the identity of these cosmic rays could be revealed by a low-cost array of radio detectors.
When UHECRs collide with gas atoms in the air, a shower of fast-moving electrons and other charged particles is triggered. As these secondary particles move in the Earth's magnetic field, they give off radio waves. Falcke and colleagues have set up an array of radio antennas, connected to digital signal-detection circuitry, at Karlsruhe in Germany. The Karlsruhe centre also houses an array of detectors for spotting the showers of particles triggered by cosmic-ray collisions. So the researchers were able to show that the radio signals detected by their array coincided with such particle showers, and are thus a genuine signature of cosmic rays. It should be possible to combine these measurements so as to deduce what the cosmic rays are made from. UHECRs are very rare, but a cheap radio array like this could monitor the skies more or less continuously, improving the detection rate.
CONTACT
Heino Falcke (Max Planck Institut Radioastronomie, Bonn, Germany. Also at: Radboud University, Nijmegen, The Netherlands and ASTRON, Netherlands Foundation for Research in Astronomy, Dwingeloo, The Netherlands)
Tel: +31 521 595 294, E-mail: [email protected]
[6] Virology: The unfolding mystery of hepatitis C (pp374-379)
Hepatitis C is a potentially fatal disease that wreaks havoc on the human liver. Now, a paper in Nature offers new insights into the structure of one of the hepatitis virus proteins, providing an important platform for future research. The findings could lead to new avenues for developing drugs to fight this form of hepatitis.
Charles Rice and his colleagues detail a new fold in the viral protein, after a close examination of its crystal structure. The discovery of this particular molecular characteristic will give drug makers a new target to work with.
CONTACT
Charles M. Rice (The Rockefeller University, New York, NY, USA)
Tel: +1 212 327 7046; E-mail: [email protected]
[7] Physics: Ringing the changes in silicon (pp325-327)
Getting devices on silicon chips to 'talk' to each other in microelectronics entails connecting them through metal wires or 'interconnects'. But in the outside world, the dense data streams and high transmission speeds of modern information networks tend to rely on pulses of light instead of electricity. An important technological challenge is to ensure efficient communication between the two.
In this week's Nature, Michal Lipson et al. show that one of the main obstacles to this blend of electronic and light-based (optical) information technology can be overcome. They have addressed the problem of using electronic signals to turn a light beam on and off: called electro-optic modulation. To be compatible with standard chip technology, electro-optic modulators must be made from silicon. But it is not easy to persuade silicon microelectronic devices to interact strongly with light - this has previously been achieved only at scales of a millimetre or so, much too large for such devices to be integrated onto chips.
The team made a silicon electro-optic modulator measuring just 12 micrometres (thousandths of a millimetre) across. It consists of a ring-shaped silicon wire placed almost within touching distance of a silicon 'waveguide' - a kind of miniature optical fibre that conducts light signals. When electrically charged particles are injected into the ring, this alters the interactions between the ring and the waveguide in such a way that the 'transparency' of the waveguide is changed. This interaction is caused by the way that light travelling down the waveguide induces a resonant 'ringing' in the silicon ring. So an electronic signal applied to the ring can effectively open and close the light-bearing channel of the waveguide. The researchers say that their device should help to promote the miniaturization of optoelectronic information technology.
CONTACT
Michal Lipson, (Cornell University, Ithaca, NY, USA)
Tel: +1 607 255 7877; Email: [email protected]
[8] Environment: North Pacific capable of catastrophic shifts (pp336-340)
Ecosystems in the North Pacific Ocean can undergo rapid, catastrophic shifts in response to climate, according to an analysis using data spanning the last century. But although biological variables such as fish populations are vulnerable to such 'regime shifts', physical variables such as sea surface temperature are not.
Theorists had previously argued as to whether the large, rapid changes reportedly spotted over the last few decades in the North Pacific are genuine events or mere blips in the general trend between, say, climate warming and increased sea surface temperature. So, George Sugihara and his colleagues evaluated a host of parameters such as temperature, sea-level pressure and fish stocks.
A complex picture emerges, the researchers reveal in this week's Nature. For physical parameters, supposed regime shifts are in fact simply 'noise' in the overall data. But biological factors are capable of genuine catastrophic shifts, suggesting that the use of fixed quotas may not be sufficient to protect threatened fish stocks.
CONTACT
George Sugihara, (University of California at San Diego, CA, USA)
Tel: +1 858 534 5582; E-mail: [email protected]
[9] Physics: Optical lattice clock could push timekeeping to new limits (pp21-324; N&V)
A cloud of trapped atoms could become the most accurate timepiece ever built, according to research published in this week's Nature.
The most accurate clocks available today use radio waves of a very specific frequency to make electrons attached to caesium atoms flip up and down. If this frequency - the clock's 'pendulum' - drifts, it is instantly corrected, so that the atomic clock keeps regular time. These clocks are accurate to one part in 1015.
Hidetoshi Katori and colleagues now report that by keeping strontium atoms trapped in a laser-generated lattice, similarly precise timekeeping can be achieved. But unlike caesium clocks, the system has the potential for accuracies as high as one part in 1018, they say.
"These clocks may help to improve technologies such as satellite navigation and broadband synchronisation that are based on precision timing," comments Thomas Udem in a related News and Views article.
CONTACT
Hidetohsi Katori, (The University of Tokyo, Japan)
Tel: +81 3 5841 6845; E-mail: [email protected]
Thomas Udem (Max-Planck-Institut fu Quantenoptik, Garching bei Munchen, Germany)
Tel: +49 89 32905 257; E-mail: [email protected]
[10] And finally - Is red a winning colour? (p293)
"Come on you reds!" is a cry heard at football grounds the length and breadth of Britain. But those dressed in scarlet may need less help than you might think-a recent survey indicates that sporting competitors are more likely to emerge victorious if they are wearing red.
Russell Hill and Robert Barton studied four one-on-one disciplines in the 2004 Athens Olympic Games - boxing, tae kwon do, Greco-Roman wrestling and freestyle wrestling-in which combatants were randomly assigned either red or blue clothing or body protectors. Those wearing red, but otherwise matched in ability to their blue-wearing opponents, were more likely to win, they report in a Brief Communication in this week's Nature.
The researchers point out that red coloration is associated with high testosterone, fitness and aggression in animals-an effect that might also operate in humans and subconsciously put an opponent on the back foot.
CONTACT
Robert Barton (University of Durham, UK)
Tel: +44 191 374 2851; E-mail: [email protected]
Russell Hill (University of Durham, UK)
Tel: +44 191 334 6201; E-mail: [email protected]
ALSO IN THIS ISSUE
[11] Lack of long-term cortical reorganization after macaque retinal lesions (pp300-307; N&V)
[12] Mechanics of the kinesin step (pp308-312; N&V)
[13] CO self-shielding as the origin of oxygen isotope anomalies in the early solar nebula (pp317-320)
[14] Sustained firing in auditory cortex evoked by preferred stimuli (pp341-346)
[15] Regulation of PDGF signalling and vascular remodelling by peroxiredoxin II (pp347-353)
[16] The Mesp2 transcription factor establishes segmental borders by suppressing Notch activity (pp354-359)
[17] Non-equilibration of hydrostatic pressure in blebbing cells (pp365-369)
[18] DNA synthesis provides the driving force to accelerate DNA unwinding by a helicase (pp370-373)
