Science & Technology
A fractal is a geometric structure in which the shapes at a large scale reflect the shapes at a small scale, forming an interlocking set of patterns that nest inside each other like Russian dolls. Approximations of fractal structures have been noticed throughout nature. For example, the overall crystal structure of a snowflake looks remarkably like the structure in a single arm. And the ridges of a mountain range jut into the sky, forming patterns similar to the crags thrusting out from a single peak.
The inlaid patterned tiles grace the walls of many structures worldwide, in patterns of mind-boggling intricacy called "girih." Historians have always assumed that medieval architects meticulously developed the patterns with basic tools.
But manuals written by the architects to share tricks of the trade actually include model tiles - like geometrical tracings - that helped lay out the complex "girih" designs [image] on a large scale, researchers discovered recently. The efficient system eventually allowed artisans to produce "quasicrystalline" wall patterns - a concept that was discovered by Western mathematicians just three decades ago.
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| ©Livermore National Laboratory |
| Stages in the penetration of an aluminium target by the Solid State Heat Capacity Laser (SSHCL). The time between frames is 167 milliseconds. |
A laser developed for military use is a few steps away from hitting a power threshold thought necessary to turn it into a battlefield weapon.
In a report scheduled for the April 9 issue of ACS' Biotechnology Progress, a bi-monthly journal, Masaru Tomita and colleagues in Japan point out that DNA has been attracting attention as perhaps the ultimate in permanent data storage.
Data encoded in an organism's DNA, and inherited by each new generation, could be safely archived for hundreds of thousands of years, the researchers state. In contrast, CD-ROMs, flash memory and hard disk drives can easily fall victim to accidents or natural disasters.
Feelix Growing is a research project involving six countries, and 25 roboticists, developmental psychologists and neuroscientists.
Co-ordinator Dr Lola Canamero said the aim was to build robots that "learn from humans and respond in a socially and emotionally appropriate manner".
The 2.3m euros scheme will last for three years.
At the start of a solar cycle, sunspots-regions on the Sun marked by cooler temperatures and intense magnetic activity-tend to appear near the poles and move towards the equator as the cycle concludes.
Dr Rossiter measured the metabolic rates of modern athletes rowing a reconstruction of an Athenian trireme, a 37m long warship powered by 170 rowers seated in three tiers.
Using portable metabolic analysers, he measured the energy consumption of a sample of the athletes powering the ship over a range of different speeds to estimate the efficiency of the human engine of the warship.
By comparing these findings to classical texts that record details of their endurance, he realised that the rowers of ancient Athens - around 500BC - would had to have been highly elite athletes, even by modern day standards.
The use of spears and axes to hunt and kill is commonly thought to have been pioneered among humanity's ancestors by males, but research has indicated weapons may have been a female invention that compensated for their lesser size and strength.
The landmark achievement is a significant step toward being able to detect life on rocky exoplanets and comes years before astronomers had anticipated.





