Za pocetak dve vesti, jedna iz fizike a druga iz psihologije o agresivnosti inferiornih sefova:
First black hole for light created on Earth
* 17:13 14 October 2009 by Anil Ananthaswamy
An electromagnetic "black holeMovie Camera" that sucks in surrounding light has been built for the first time.
The device, which works at microwave frequencies, may soon be extended to trap visible light, leading to an entirely new way of harvesting solar energy to generate electricity.
A theoretical design for a table-top black hole to trap light was proposed in a paper published earlier this year by Evgenii Narimanov and Alexander Kildishev of Purdue University in West Lafayette, Indiana. Their idea was to mimic the properties of a cosmological black hole, whose intense gravity bends the surrounding space-time, causing any nearby matter or radiation to follow the warped space-time and spiral inwards.
Narimanov and Kildishev reasoned that it should be possible to build a device that makes light curve inwards towards its centre in a similar way. They calculated that this could be done by a cylindrical structure consisting of a central core surrounded by a shell of concentric rings.
There's no escape
The key to making light curve inwards is to make the shell's permittivity – which affects the electric component of an electromagnetic wave – increase smoothly from the outer to the inner surface. This is analogous to the curvature of space-time near a black hole. At the point where the shell meets the core, the permittivity of the ring must match that of the core, so that light is absorbed rather than reflected.
Now Tie Jun Cui and Qiang Cheng at the Southeast University in Nanjing, China, have turned Narimanov and Kildishev's theory into practice, and built a "black hole" for microwave frequencies. It is made of 60 annular strips of so-called "meta-materials", which have previously been used to make invisibility cloaks.
Each strip takes the form of a circuit board etched with intricate structures whose characteristics change progressively from one strip to the next, so that the permittivity varies smoothly. The outer 40 strips make up the shell and the inner 20 strips make up the absorber.
"When the incident electromagnetic wave hits the device, the wave will be trapped and guided in the shell region towards the core of the black hole, and will then be absorbed by the core," says Cui. "The wave will not come out from the black hole." In their device, the core converts the absorbed light into heat.
Narimanov is impressed by Cui and Cheng's implementation of his design. "I am surprised that they have done it so quickly," he says.
Fabricating a device that captures optical wavelengths in the same way will not be easy, as visible light has a wavelength orders of magnitude smaller than that of microwave radiation. This will require the etched structures to be correspondingly smaller.
Cui is confident that they can do it. "I expect that our demonstration of the optical black hole will be available by the end of 2009," he says.
Such a device could be used to harvest solar energy in places where the light is too diffuse for mirrors to concentrate it onto a solar cell. An optical black hole would suck it all in and direct it at a solar cell sitting at the core. "If that works, you will no longer require these huge parabolic mirrors to collect light," says Narimanov.
Journal references: Applied Physics Letters (vol 95, p041106), and "An electromagnetic black hole made of metamaterials" by Tie Jun Cui and Qiang Cheng's (preprint archive)
It's official: Your bullying boss really is an idiot
* 14:28 15 October 2009 by Ewen Callaway
* For similar stories, visit the The Human Brain Topic Guide
Got a bullying boss? Take solace in new research showing that leaders who feel incompetent really do lash out at others to temper their own inferiority.
"Power holders feel they need to be superior and competent. When they don't feel they can show that legitimately, they'll show it by taking people down a notch or two," says Nathanael Fast, a social psychologist at the University of Southern California in Los Angeles, who led a series of experiments to explore this effect.
In one, Fast and his colleague Serena Chen, who is at the University of California, Berkeley, asked 90 men and women who had jobs to complete online questionnaires about their aggressive tendencies and perceived competence. The most aggressive of the lot tended to have both high-power jobs and a chip on their shoulder, Fast and Chen found.
To see if a bruised ego can actually cause aggression, the researchers manipulated people's sense of power and self-worth by asking them to write about occasions when they felt either empowered or impotent and then either competent or incompetent. Previous research has suggested that such essays cause a short-term bump or drop in feelings of power and capability, Fast says.
Next, Fast and Chen asked their volunteers to select a punishment to be given to university students for wrong answers in a hypothetical test of learning. Volunteers chose between horn sounds that ranged from 10 decibels to a deafening 130 decibels.
The volunteers who felt the most incompetent and empowered picked the loudest punishments – 71 decibels on average. Workers who felt up to their jobs, selected far quieter punishments, between 55 and 62 decibels, as did those primed to feel incompetent yet powerless.
Flattery seems to temper the aggressive urges of insecure leaders. When Fast and Chen coaxed the egos of these volunteers by praising their leadership skills, their aggressive tendencies all but disappeared. This is proof that leaders are aggressive because of a hurt ego, not simply a threat to their power, Fast says.
This might also explain why leaders of organisations both big and small surround themselves with yes-men and women, he says.
Blind flattery may not be the best solution for the 54 million US citizens estimated to have experienced workplace bullying (PDF). But easing leaders into new positions of power, or telling them that it's natural to feel daunted, could prevent future outbursts, says Adam Galinsky , a social psychologist at Northwestern University's Kellogg School of Management in Evanston, Illinois.
Journal reference: Psychological Science, DOI: 10.1111/j.1467-9280.2009.02452.x