Monday, July 12, 2010
Tuesday, June 29, 2010
Sunday, June 27, 2010
Brownian motion of particles
Science/AAAS | This Week in Science: 25 June 2010; 328 (5986): "Nearly 200 years ago, the botanist Robert Brown noted that pollen particles floating on a liquid displayed a random motion, jittering under the microscope as if the particles were alive. In 1905, Albert Einstein described this Brownian motion in terms of statistical thermodynamics. Now, Li et al. (p. 1673, published online 20 May) use a single, optically trapped silica bead to probe the dynamics of Brownian motion, measuring the predicted instantaneous velocity of the particle and verifying the short-time-scale behavior predicted a century ago. As well as testing fundamental principles of physics, the technique also has practical implications for cooling particles to ultralow temperatures."
Earth's 100,000 years cycle of glaciation and deglaciation
Science/AAAS | This Week in Science: 25 June 2010; 328 (5986)
For the past half-million years, our planet has passed through a cycle of glaciation and deglaciation every 100,000 years or so. Each of these cycles consists of a long and irregular period of cooling and ice sheet growth, followed by a termination—a period of rapid warming and ice sheet decay—that precedes a relatively short warm interval. But what causes glacial terminations? Denton et al. (p. 1652) review the field and propose a chain of events that may explain the hows and whys of Earth's emergence from the last glacial period. Pulling together many threads from both hemispheres suggests a unified causal chain involving ice sheet volume, solar radiation energy, atmospheric carbon dioxide concentrations, sea ice, and prevailing wind patterns.
For the past half-million years, our planet has passed through a cycle of glaciation and deglaciation every 100,000 years or so. Each of these cycles consists of a long and irregular period of cooling and ice sheet growth, followed by a termination—a period of rapid warming and ice sheet decay—that precedes a relatively short warm interval. But what causes glacial terminations? Denton et al. (p. 1652) review the field and propose a chain of events that may explain the hows and whys of Earth's emergence from the last glacial period. Pulling together many threads from both hemispheres suggests a unified causal chain involving ice sheet volume, solar radiation energy, atmospheric carbon dioxide concentrations, sea ice, and prevailing wind patterns.
Thursday, June 24, 2010
Neutrino search
A hard-to-observe fundamental particle that travels alone, the neutrino has little or no mass, so rarely interacts with other particles.
Neutrinos are ubiquitous throughout our universe. They were produced during the Big Bang, and many of those are still around. New ones are constantly being created too, through natural occurrences like solar fusion in the sun's core, or radioactive elements decaying in the Earth's mantle, as well as when the particle accelerator at Fermilab purposely smashes protons into carbon foils.
Our sun produces so many that hundreds of billions are zinging through our bodies every second, Coan said. It's hoped the new detector can resolve questions surrounding three different kinds of neutrinos — electron, tau and muon — and their "oscillation" from one type to another as they travel, he said.
Scientists at the new detectors will analyze data from Fermilab's neutrino beam to observe evidence of neutrinos when the speedy, lightweight particles occasionally smash into the carbon nuclei in the scintillating oil of the detector, causing a burst of light flashes, Coan said.
NOvA is looking for the most elusive oscillation of the muon type of neutrino to the electron type, Cooper said.
More information: http://www-nova.fnal.gov/
Monday, February 2, 2009
Sakshat, India's Rs. 500 laptop , to be launched today
India to unveil the £7 laptop
Government hopes its mini-computer, the world's cheapest, will bridge the digital divide between rich and poor
Randeep Ramesh in New Delhi
guardian.co.uk, Monday 2 February 2009 16.37 GMT
Article history
The credit crunch computer is set to arrive tomorrow in India when officials unveil the 500 rupee (£7.25) laptop. In an attempt to bridge the "digital divide" in the country between rich and poor, the government will show off the prototype, low-cost laptop as the centrepiece of an ambitious e-learning programme to link 18,000 colleges and 400 universities across the country.
India has a reputation for creating ultra-cheap technologies, a trend sparked last year by the Tata Nano, the world's cheapest car at Rs100,000 (£1,450).
The computer, known as Sakshat, which translates as "before your eyes", will be launched as part of a new Rs46bn "national mission for education". This envisages a network of laptops from which students can access lectures, coursework and specialist help from anywhere in India, triggering a revolution in education. A number of publishers have reportedly agreed to upload portions of their textbooks on to the system. More
Prabhakar Rao, vice-chancellor of the university in Andhra Pradesh from where the Sakshat will be launched, said that India was "looking to get the hardware and software cheaper. In a developing country, costs have to be kept low so that the maximum number of students will benefit. That means cheap computers and cheap broadband access, so that students get access to ebooks and ejournals."
Although half of India's 1 billion people are aged below 25, the country has fallen behind in terms of university places, with only 11% of students enrolled, compared with double that in China. India's bigger northern neighbour already has 180 million internet users, five times India's total.
Designed by scientists at the Vellore Institute of Technology, the Indian Institute of Science in Bangalore, the Indian Institute of Technology in Madras and the state-controlled Semiconductor Complex, the laptop has 2Gb of Ram and wireless connectivity. In an attempt to keep costs low, experts say it is unlikely to use familiar Microsoft Windows software.
Officials are confident that the Rs500 price tag can be met. RP Agarwal, the top civil servant for Indian higher education, told newspapers last week that "at this stage, the price is working out to be $20 [Rs1,000] but with mass production it is bound to come down."
Government hopes its mini-computer, the world's cheapest, will bridge the digital divide between rich and poor
Randeep Ramesh in New Delhi
guardian.co.uk, Monday 2 February 2009 16.37 GMT
Article history
The credit crunch computer is set to arrive tomorrow in India when officials unveil the 500 rupee (£7.25) laptop. In an attempt to bridge the "digital divide" in the country between rich and poor, the government will show off the prototype, low-cost laptop as the centrepiece of an ambitious e-learning programme to link 18,000 colleges and 400 universities across the country.
India has a reputation for creating ultra-cheap technologies, a trend sparked last year by the Tata Nano, the world's cheapest car at Rs100,000 (£1,450).
The computer, known as Sakshat, which translates as "before your eyes", will be launched as part of a new Rs46bn "national mission for education". This envisages a network of laptops from which students can access lectures, coursework and specialist help from anywhere in India, triggering a revolution in education. A number of publishers have reportedly agreed to upload portions of their textbooks on to the system. More
Prabhakar Rao, vice-chancellor of the university in Andhra Pradesh from where the Sakshat will be launched, said that India was "looking to get the hardware and software cheaper. In a developing country, costs have to be kept low so that the maximum number of students will benefit. That means cheap computers and cheap broadband access, so that students get access to ebooks and ejournals."
Although half of India's 1 billion people are aged below 25, the country has fallen behind in terms of university places, with only 11% of students enrolled, compared with double that in China. India's bigger northern neighbour already has 180 million internet users, five times India's total.
Designed by scientists at the Vellore Institute of Technology, the Indian Institute of Science in Bangalore, the Indian Institute of Technology in Madras and the state-controlled Semiconductor Complex, the laptop has 2Gb of Ram and wireless connectivity. In an attempt to keep costs low, experts say it is unlikely to use familiar Microsoft Windows software.
Officials are confident that the Rs500 price tag can be met. RP Agarwal, the top civil servant for Indian higher education, told newspapers last week that "at this stage, the price is working out to be $20 [Rs1,000] but with mass production it is bound to come down."
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