Some other topics to muse while I put off going to bed.
* A philanthropist named Mark Bent has an excellent sense of pressure points, areas where a modest investment and limited technogy can yield a huge improvement in many lives. Too often would-be benefactors decide in advance what they want to give and then engage in expensive and often futile efforts to change the recipients’ behavior around the gift. This is my major beef with the hundred dollar laptop – it will be a nice addition for the local equivalent of a middle class, but any kind of electronic technology is simply too flimsy and high-maintenance for the people who need charity the most. When a computer expert decides that everybody needs a computer it looks to me like a hammer deciding that everything is a nail. Mark Bent spent enough time in Eritrea to see that a simple problem like nighttime darkness was putting a major limitation on people’s lives, so he developed a super-rugged solar powered flashlight that can last three years before replacing a pair of AA batteries. I would file this with microcredit and the supermoneymaker water pump as the kind of idea I want to see more often.
* The metamaterial phenomenon promises advances like cloaking and a perfect optical lens (e.g., no diffraction limit on how small you can focus). These ideas, which work to a limited degree in a laboratory setting, keep closing in on usable real-world applications (original references here and here).
At the heart of the hyperlens concept4, 5 lies a nanostructured ‘metamaterial’ whose dielectric constant — a measure of a material’s response to the electric field of the incident light — has opposite signs in two orthogonal directions. The effect of this anisotropy is to do away with the lower limit on the wavelength of a propagating field that is characteristic of a conventional, isotropic medium. With no lower limit on the propagating light’s wavelength, there is no diffraction limit — and so, theoretically, unbounded image resolution.
As soon as waves of very small wavelength emerge from this ‘optical hyperspace’ into air, however, they can no longer propagate, and again become evanescent. To deliver the sub-wavelength information carried by such waves into the far field, one must first increase their wavelength to the point when propagation in air is possible. The cylinder (or half-cylinder) geometry of the hyperlens is specifically designed to achieve this, by slowly increasing the wavelength as the field spreads away from the centre of the device (Fig. 1).
In their experimental realizations of the hyperlens, Liu et al.1, of the University of California, Berkeley, and Smolyaninov et al.2, of the University of Maryland, Baltimore, use a half-cylinder1 and a cylinder2 of layered metamaterials whose dielectric constant is strongly isotropic in the radial and tangential directions. The objects to be imaged are placed in the hollow middle and illuminated from the outside — in Smolyaninov and colleagues’ case, from the top of the cylinder, and for Liu and colleagues from the side of the half-cylinder.
When industry gets a better grasp on making and using this technology I can promise some very, very weird products.
* Sleep before you study. A new report shows that memory formation is dramatically inhibited when you don’t sleep enough. [Edit] Here is a summary, although the text is subscription-only. Find the original paper here.
In the experiment the researchers studied two groups of young adults. A first group stayed awake for one night before watching a slide show, at 6 pm, of 150 non-emotional slides presented through special LCD goggles, while their brains were scanned using functional magnetic resonance imaging (fMRI). The control group spent a normal night at home with no sleep restrictions before undergoing the same procedure as the sleep deprived group. After the slide show, all 28 subjects went home to sleep, with no sleep restrictions. The following evening the participants took a pop quiz on the slides they had seen 24 hours earlier; 75 new slides were randomly mixed with the original 150 slides and presented one by one on a computer screen. Immediately after each image, participants had to indicate whether they had seen it before.
Yoo et al. [12] found that those participants who had been sleep deprived on the first night performed worse compared to the control group — even though they had had a night to catch up on their sleep. By contrasting the fMRI data obtained during the initial viewing of the slides, the authors were able to attribute the impaired memory performance in the sleep deprived group to a deficit in hippocampal activity. Interestingly, the hippocampal complex, lying deep under the frontal cortex, is a region known to be critically involved in short term memory such as learning of new episodic memories like memorizing pictures.
ThymeZone
That reminds me of my favorite admonition here, “Don’t post drunk.”
If only more of my fellow lefties would follow that proscription!
Rome Again
I haven’t had a drink in weeks, what’s my excuse?
Andrew
The not sleeping thing is pretty old news.
However, I see no problems with posting, studying, or sleeping while drunk.
Andrew
I think I see the problem. It has something to do with not having a drink in weeks.
The Other Steve
The $150(it’s no longer $100) laptop fiasco is a solution in search of a problem.
It’s like deciding the problem with starving people is that they don’t have Prada shoes to wear.
Andrew
The problem it solves is quite obvious:
As a vanity project for elitist technology types, it helps them receive praise from a sycophantic press corps who live in the same first world cities and are uninterested in actually reporting on the living conditions of the third world.
Press release journamalism FTW!
Andrew
Nicholas Negroponte, barely paraphrased, just now on 60 minutes: The first English word used by some poor Cambodian children, who live in a village without sanitation, was “google.”
Gag me with a fucking OLPC.
The Other Steve
It reminds me of the doctor I heard interviewed on NPR. I don’t remember what relief agency he was with, might have been doctors without borders or something. But he was talking about AIDS in Africa, and how to try to manage it.
I forget the exact context, but they began talking about drug availability at low cost.
He said, cost wasn’t really the main issue. The main problem was that most AIDS management drugs are a cocktail of drugs that must be taken on a rigorous schedule. This pill every 4 hours, this one every 8, etc.
The problem is most of the people don’t have clocks.
There are multiple problems that need to be solved together.
On the other hand, maybe people like not having all of the modern stuff in the world.
vttex
What the hell language was that first section written in? Was that really English?
Fe E
Hey-soos Vega!
That hyperlens topic easily equals the number of times I’ve seen the word “anisotropy” since I took optical mineralogy in 1992!
Way to knock the rust off of my brain this morning Tim!
When they refer to a strongly isotropic dielectric in the radial and tnagaential directions, I need a bit of clarification: Is this with respect to a cylinder, and is the tangent refered to the longitudinal axis of the cylionder, or tangent to the outer surface of the cylinder?
Optics always made my head hurt. I feel dizzy. I’m gonna lie down now.
And now I’ll need to look for ways to use “orthogonal” in a sentence now. It was always my favorite of the six crytal classes–not too little symmetry (monoclinic) and not too much (isotropic). ;)
Fe E
I type good!
crytal = crystal
tnagaential(wtf) = tangential
Tim F.
I really hope that you’re not asking me.
Fe E
Awwww c’mon Tim–I was hoping you’d do the hard reading so I wouldn’t have to!
To be blunt however, even if you did answer that question, I’m sure I wouldn’t know why it would matter-I’ll just take their word that it does. I just like to keep my spatial orientation/visualization accurate.
On the other hand, I can’t help but feel like I just won a round of “stump the band.”
Mark
Tim,
Are you familiar with the TED conference website? Lots of that kind of stuff to be found here. One of my favorites:
Amy Smith: Simple designs that could save millions of childrens’ lives