Month: September 2012

An aqueous computer based on water droplets rolling around a superhydrophobic surface has been developed by researchers in Finland. See flip-flop memory logic in action:

Source

From the abstract to the paper: “When water droplets impact each other while traveling on a superhydrophobic surface, we demonstrate that they are able to rebound like billiard balls.” We present elementary Boolean logic operations and a flip-flop memory based on these rebounding water droplet collisions. Furthermore, bouncing or coalescence can be easily controlled by process parameters. Thus by the controlled coalescence of reactive droplets, here using the quenching of fluorescent metal nanoclusters as a model reaction, we also demonstrate an elementary operation for programmable chemistry.”

So, what is making the droplet flip and flop so that it goes left-right alternately. I asked team leader Robin Ras to explain:

“You can see that the droplet that is standing still is actually located in a bistable depression (in the shape of an 8). Each depression is slightly off-axis, so that when the moving droplet hits it, it kicks the droplet at an angle. As in classical Newtonian mechanics (for action there is an equal and opposite reaction), the first moving droplet is going into the other direction (and slowing down as it transfers its momentum) and fits into the other depression.” Hence the alternating. “Simple but beautiful,” Ras told me.

More droplet logic videos.

Mertaniemi, H., Forchheimer, R., Ikkala, O. & Ras, R.H.A. (2012). Rebounding Droplet-Droplet Collisions on Superhydrophobic Surfaces: from the Phenomenon to Droplet Logic, Advanced Materials, n/a. DOI: 10.1002/adma.201202980

Interesting search phrase brought someone to the Sciencebase site:

“for how long should you be watching out for a stroke after a cheiro practioner aligns your neck?”

Spelling and grammar aside, I presume the visitor was concerned about the problem of cerebral stroke that has been known to occur following manipulation of neck vertebra by a chiropractic where damage to the carotid arteries that carry blood to the brain can occur.

A recent study by American neurosurgeons reported in The Guardian adds to evidence suggesting chiropractic can damage arteries supplying the brain. The NHS CHoices site provided by the UK’s National Health Service points out that “Serious complications that have been linked to spinal manipulation include: tearing of an artery wall, leading to stroke injury to the spinal column, leading to paralysis build-up of blood between the skull and the outer layers of the brain, which can result in coma or death.”

Don’t let any bone-cruncher near your neck…or any other bits of you. None of these “alternative” manipulation techniques are supported by scientific evidence. Remember, anecdote is not evidence, some people see practitioners and quacks and claim miraculous recovery…there is a vague chance that something a quack does has an effect, but more likely is that they were going to recover anyway, given time. Reversion to the mean.

When we were kids, Dad used to have this recurring joke (actually, he still does have lots of recurring jokes), we’d be out walking and as we set off he’s say “Follow me, I’m right behind you”. Obviously, at first glance a purely oxymoronic statement akin to “Hurry up and take your time” or “that’s a definite maybe” or a “blatant innuendo” etc.

I was reminded of the phrase by Toa Fraser who quoted Leonard Cohen on Twitter: “Follow me,” the wise man said/But he walked behind.”

My parents have always been behind me, not leading from the rear as generals do in wars from the safety of their armoured bunkers, but suppportive. My mother’s jokes are more spontaneous than some of my Dad’s, less catchphrase, more spontaneous wit. They laugh a lot. Anyway, with my book “finished” (it’s with the typesetter this week), I thought I’d share with you some acknowledgements, which will be in the print edition:

Thanks to author and radio presenter Tim Lihoreau for helping to get the project started, and to E&T’s Olivia Bays for nurturing my first solo book so gently. Thanks also to John Woodruff for expert editing and for trapping escaped facts and oversights.

Thanks to the various scientific contacts who validated chapters, and to all those sceptics on the web who kindly provide information that corroborates facts in the book and tirelessly overturn the deceived wisdom. Also, thanks to my loyal Facebook and Twitter followers for their enthusiasm, suggestions and pre-orders, and to you for finding your own inner scientist.

Thanks to my children for their initial excitement when they learned that Dad was writing a book without co-authors, and for their amusement at the bald character on the cover, who bears no little resemblance to the author. Thanks too to my parents for supporting my inner geek.

Most of all, thanks to my wife, Tricia, for her patience during the writing and editing process when late nights, early mornings, and nocturnal ‘light bulb moments’ often precluded a good night’s sleep for both of us. I hope you and she think it was all worth it.

According to stats prof David Spiegelhalter, whom I met for the first time only this year, “Our survival is governed by the “force of mortality” – the wonderfully archaic expression for the chance of dying each year. Each year, an average adult ages, this unavoidable force increases by around 9%, so that every eight years your chance of not making your next birthday roughly doubles.”

He is thus wondering whether he will live longer than his 20-year old cat (that’s 100 in cat years, I believe). Our cat, died at 15 (equiv to 75), I think I’d like to get somewhere closer to Spiegelhalter’s cat’s longevity and sidestep the Schrodinger risk…

via BBC News – Will I live longer than my cat?