David Kirkpatrick

July 14, 2010

Exercise improves your mental health

Via KurzweilAI.net — regular exercise provides many, many benefits and it’s not surprising improved mental health is among them. Since you’re reading this in front of a computer, take a few minutes sometime today to at least go on a brisk walk. Personally I do a bit of physical exercise, but nothing like I did when I was much younger. Now I completely swear by a 30 minute to hour daily workout on the Wii Fit Plus. For some reason I enjoy the idea of having a virtual trainer guiding my workout. It has something of “the future has arrived” science-fictiony feel to it for me.

Exercise reduces anxiety and depression

Exercise can ameliorate anxiety and depression-like behaviors induced by an adverse early-life environment by altering the chemistry of the hippocampus, the part of the brain that regulates stress responses, researchers from the University of New South Wales (UNSW) have found.

In the study, rats were divided into groups and either isolated from their mothers for controlled periods of time to induce stress or given normal maternal contact. Half were given access to a running wheel. In addition to being more anxious, animals that were subjected to stress early in life had higher levels of stress hormones and fewer steroid receptors in the part of the brain controlling behaviour.

“Both the anxious behaviour and the levels of hormones in these rats were reversed with access to the exercise wheel,” said UNSW Professor of Pharmacology Margaret Morris.

“We know that exercise can elevate mood, but here we are seeing chemical changes that may underpin this improvement. One of these is increases in brain-derived neurotrophic factor (BDNF), which helps nerve cells grow.

“Many neurological diseases appear to have their origins early in life. Stress hormones affect the way nerve cells grow in the brain. This discovery may be giving us a clue about a different way to tackle a range of conditions that affect mood and behaviour,” she said.

More info: University of New South Wales news

Here’s the PhysOrg take on this story.

December 7, 2009

Introducing the one-atom transistor

Via KurzweilAI.net — This really is just amazing. A transistor made of one single atom of phosphorus.

Single-atom transistor created
KurzweilAI.net, Dec. 7, 2009

A working transistor whose active region comprises only of a single phosphorus atom in silicon has been built byresearchers from Helsinki University of Technology, University of New South Wales, and University of Melbourne.

The device uses sequential tunneling of single electrons between the phosphorus atom and the source and drain leads of the transistor. The tunneling can be suppressed or allowed by controlling the voltage on a nearby metal electrode with a width of a few tens of nanometers.

The researchers plan to use the spin degree of freedom of an electron of the phosphorus donor as a quantum bit (qubit). They were able to observe spin up and down states for a single phosphorus donor in a magnetic field for the first time–a crucial step towards the control of these states in realizing a qubit.


(a) Scanning electron microscope image of single-atomtransistor
(b) Differential conductance through the transistor with 4 Tesla magnetic field

More informationHelsinki University of Technology news

October 23, 2008

Solar cell with 25% efficiency

Solar keeps improving by leaps and bounds these days. Encouraging news from the University of New South Wales.

The release:

Magic solar milestone reached

UNSW claims 25 percent solar cell efficiency title

UNSW’s ARC Photovoltaic Centre of Excellence has again asserted its leadership in solar cell technology by reporting the first silicon solar cell to achieve the milestone of 25 per cent effiency.

The UNSW ARC Photovoltaic Centre of Excellence already held the world record of 24.7 per cent for silicon solar cell efficiency. Now a revision of the international standard by which solar cells are measured, has delivered the significant 25 per cent record to the team led by Professors Martin Green and Stuart Wenham and widened their lead on the rest of the world.

Centre Executive Research Director, Scientia Professor Martin Green, said the new world mark in converting incident sunlight into electricity was one of six new world records claimed by UNSW for its silicon solar technologies.

Professor Green said the jump in performance leading to the milestone resulted from new knowledge about the composition of sunlight.

“Since the weights of the colours in sunlight change during the day, solar cells are measured under a standard colour spectrum defined under typical operational meteorological conditions,” he said.

“Improvements in understanding atmospheric effects upon the colour content of sunlight led to a revision of the standard spectrum in April. The new spectrum has a higher energy content both down the blue end of the spectrum and at the opposite red end with, dare I say it, relatively less green.”

The recalibration of the international standard, done by the International Electrochemical Commission in April, gave the biggest boost to UNSW technology while the measured efficiency of others made lesser gains. UNSW’s world-leading silicon cell is now six per cent more efficient than the next-best technology, Professor Green said. The new record also inches the UNSW team closer to the 29 per cent theoretical maximum efficiency possible for first-generation silicon photovoltaic cells.

Dr Anita Ho-Baillie, who heads the Centre’s high efficiency cell research effort, said the UNSW technology benefited greatly from the new spectrum “because our cells push the boundaries of response into the extremities of the spectrum”.

“Blue light is absorbed strongly, very close to the cell surface where we go to great pains to make sure it is not wasted. Just the opposite, the red light is only weakly absorbed and we have to use special design features to trap it into the cell,” she said.

Professor Green said: “These light-trapping features make our cells act as if they were much thicker than they are. This already has had an important spin-off in allowing us to work with CSG Solar to develop commercial ‘thin-film’ silicon-on-glass solar cells that are over 100 times thinner than conventional silicon cells.”

ARC Centre Director, Professor Stuart Wenham said the focus of the Centre is now improving mainstream production. “Our main efforts now are focussed on getting these efficiency improvements into commercial production,” he said. “Production compatible versions of our high efficiency technology are being introduced into production as we speak.”

The world-record holding cell was fabricated by former Centre researchers, Dr Jianhua Zhao and Dr Aihua Wang, who have since left the Centre to establish China Sunergy, one of the world’s largest photovoltaic manufacturers. “China was the largest manufacturer of solar cells internationally in 2007 with 70 per cent of the output from companies with our former UNSW students either Chief Executive Officers or Chief Technical Officers”, said Professor Green.

 

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