The best way to hit the target when throwing
Baseball legend Satchel Paige had a simple philosophy when it came to pitching: Keep the ball away from the bat.
Throwing is one of the most complex actions humans perform. Even tossing a crumpled piece of paper into a rubbish bin requires a series of complex neurological and mechanical calculations.
Scientists at Harvard University decided to use mathematical models to figure out the best ways to throw something at a target.
"There are many different ways to get an object to a target," said the study's senior author Professor L. Mahadevan. "Our hypothesis was that you choose based on a strategy that minimises the error at the target while giving yourself the greatest room for error at the release."
The researchers, who recently published their findings in Royal Society Open Science, analysed the paths of thrown objects.
They found that while underhand throws are best for reaching a target close by and above the shoulder, overhand throws are more accurate for targets below the shoulder and are more forgiving to errors over long distances.
They also found that the most accurate throw is slightly faster than the minimum speed needed to reach the target. The faster the throw, the less likely it is to be accurate. At both high speeds and longer distances, the overarm throw beats the underhand throw in accuracy.
The study added that the ability to hit a target was important to early humans , as the ability to throw a stone or spear was a primary method of hunting.
Stroke prevention plan also reduces dementia
A stroke prevention strategy in Ontario appears to have had an unexpected, beneficial side effect - a reduction in the incidence of dementia among people over 80.
Researchers in Canada have found a decade-long drop in new cases of both stroke and dementia in the age group, after analysing data from the Institute for Clinical Evaluative Sciences.
Cases of stroke fell by almost 40 per cent, and those of dementia fell by about 15 per cent.
Ontario's stroke prevention strategy, launched in 2000, added more health centres to manage stroke, more community and physician support, better high blood pressure treatment and promotion of lifestyle changes to reduce risk of stroke.
"What this data suggests is that by successfully fighting off the risks of stroke - with a healthy diet, exercise, a tobacco-free life and high blood-pressure medication where needed - we can also curtail the incidence of some dementias," said study author Joshua Cerasuolo, a PhD student at Canada's Western University.
The findings were published in the journal Alzheimer's & Dementia: The Journal Of The Alzheimer's Association.
"That's a pretty powerful one-two punch," said the study's co-supervisor, Dr Vladimir Hachinski. He added that more research is needed to better understand the link between stroke and dementia, but this work already suggests health policies relating to stroke and dementia can be coordinated.
Most strokes are caused by the restriction of blood flow to the brain. Dementia also develops as blood supply to the brain reduces.
Dr Hachinski said someone who has had a stroke is twice as likely to develop dementia. Someone who has had a diagnosis of stroke has also likely had several prior "silent" strokes that may have affected the patient's cognitive abilities.
Bacteria-killing paper could be worn in future
Researchers in the United States have invented an inexpensive and effective way to kill bacteria and sanitise surfaces with devices made of paper, which they say could eventually be used in protective clothing.
The team led by Rutgers University in New Jersey coated paper with thin layers of aluminium in a honeycomb pattern. By applying high voltage to stacked sheets of the metallised paper, they generate "plasma", a hot and electrically charged gas that kills microbes.
The fibrous structure of the paper allows gas to permeate it, preventing overheating.
"Paper is an ancient material, but it has unique attributes for new, high-tech applications," said Assistant Professor Aaron Mazzeo.
In experiments, the paper-based sanitisers killed more than 99 per cent of Saccharomyces cerevisiae, a yeast species, and more than 99.9 per cent of Escherichia coli, a bacteria found in the gut and commonly used in research.
"Preliminary results showed that our sanitisers can kill spores from bacteria, which are hard to kill using conventional sterilisation methods," said co-author Richard Chen.
The findings were published this week in the Proceedings Of The National Academy Of Sciences.
In future, paper-based sanitisers may be suitable for clothing that sterilises itself, devices that sanitise laboratory equipment and smart bandages to heal wounds, among other uses, said the researchers.
The motivation for this study was to create personal protective equipment that might contain the spread of infectious diseases, such as the devastating 2014 outbreak of Ebola in West Africa.
Compiled by Lin Yangchen