Tuesday, February 9, 2016

The stealthy third-rail of American politics

What do you think of this: spending over $1 trillion over the next twenty years for 2,400 stealthy F-35 Joint Strike Fighter jets? That's over $400 million per plane. The helmets that the pilots will wear, alone, cost over $400,000 a pop.

Bernie thinks it's a good idea.
Hillary thinks it's a good idea.
Trump and Cruz and Rubio and Jeb all think it's a good idea.

So much for finally finding something that we can all agree on.

The amount of money being wasted here is mind-boggling. And wasted is the right word, since no compelling case has been made that this weapons system boondoggle will do anything to address our genuine national security concerns.

This number of better things that we could do with this vast sum is itself mind-boggling.

We could provide free college and vocational training for young people for decades. Teachers could be paid the kind of salaries that would allow us to recruit and retain the best and the brightest of them. Our crumbling infrastructure could be repaired or replaced if need be. World-class public transportation systems could be built that would become the preferred way for everyone to get around. Sources of clean energy could be developed and our environment restored in the process. And, for a relative pittance, no city, town, or village in the country would have to settle for providing its residents with anything but the highest quality drinking water.

The list goes on.

So why is everyone behind such a bad idea? The reason is that the United States has become a warrior culture; you can stake out any position you damn well please across the political spectrum, but you can't say anything that in any way could be construed as calling into question the premise of unrivaled and enduring American military power around the world.

Military spending has become the "third-rail" of American politics. No one dares touch it.

Sunday, February 7, 2016

Thinking outside the petri dish - an ingenious application of microfluidics

Petri dish with bacterial colonies 
The easily recognized, circular, slim glass petri dish has been a mainstay of microbiology research since the late 1870s, when it was invented by Julius Richard Petri, an assistant to the pioneering German microbiologist Robert Koch.

Filled with agar, a jelly-like substance, obtained from algae, which has been infused with selected nutrients, the petri dish becomes a go-to habitat for cultivating a variety of microbes, everything from bacteria to small mosses.

But for all its successes as an instrument of biological and biomedical studies - and they are legion - petri dishes fall short in some regards. In particular, once the liquid agar and its mix of nutrients and any other selected chemicals set, you're pretty much stuck with the environment for your microorganisms that you decided on in advance.

But what if you wanted to do an experiment that required you to change the nutrient environment over time? Are there options to using the tried-and-true, but inflexible, approach that the petri dish has to offer?

Microfluidics devices used to direct the evolution of
C. elegans at the McGrath lab (Marc Merlin)
An answer can be found in the so-called lab-on-a-chip, like the set of five pictured here on a wafer fabricated by Georgia Tech School of Biology graduate student Lijian Long and used by the McGrath lab there to direct the evolution of a tiny roundworm with the official name C. elegans.

These are microfluidics devices. They resemble computer chips for a good reason: they are constructed using the same micro-scale techniques used to make those components so central to our digital technology. The key difference is that, unlike computer chips which are designed to control the flow of electrons, microfluidics devices are designed to allow for the exquisite control of the flow of fluids.

In this case of the McGrath research group, the fluid being controlled contains, in part, bacteria found in decaying organic matter, a preferred meal for C. elegans. (Nom, nom, nom, as they say.) The roundworms, only around three-quarters of a millimeter in length, take up residence in the winding, narrow channel inscribed on the microfluidics device and feed on the bacteria that come their way.

By modulating the concentration of these bacteria, among other things, the McGrath lab is able to interfere with the usual development of C. elegans with the intention of driving the evolution of specific traits, for example those having to do with lifespan.

These kind of innovative labs-on-a-chip were developed early on by Georgia Tech School of Chemical & Biomolecular Engineering Professor, Hang Lu. They are wonderful examples of how science proceeds not only through the production of remarkable primary discoveries but also through the development of ingenious auxiliary experimental techniques which require thinking outside the box. In this case, one could say, thinking outside the petri dish.

Wednesday, January 20, 2016

So long, Copenhagen - I'm a Many Worlds believer now

This is adapted from a status update I posted on Facebook

I am pleased to announce that, in large part due to the wonderful explanations by physicist Sean Carroll, I now subscribe to the Many-Worlds Interpretation (MWI) of quantum mechanics.

MWI is not at all new to me. It's been kicking around since 1957 when it was first proposed by Hugh Everett while he was a graduate student at Princeton. I was certainly aware of it when I started my physics studies back in the early 1970s.

I had never taken the interpretation seriously, mostly because I was put off by the notion that the act of measuring a physical system generated new worlds somehow, one world for each of the possible values of the result of that measurement. This elevator-pitch description of MWI struck me as both magical and untestable and, so, not really worth my time.

Recently, though, I have decided to revisit the topic.

The so-called Copenhagen Interpretation of quantum mechanics on which I and most physics graduate students of my generation were weaned has not really weathered well. In some respects, it was considered provisional even back then, a placeholder waiting for something better to come along. I had counted on the fact that its own magical elements - the putative role of consciousness in measurement and the non-local collapse of the wave function - would have been put on a stronger intellectual footing in the last forty years. But that hasn't really happened.

Thanks to Sean, whose thoughts on some of the central philosophical questions of modern physics have become a go-to resource for me, I decided to take another look at MWI and now frankly could kick myself for not investigating it sooner.

Now, I understand that MWI is a straightforward outcome if you take the equations of quantum mechanics at face value and don't add the unnecessary - and problematic - assumption that observers somehow exist outside the physical systems that they observe. Indeed, Hugh Everett's dissertation had the title, The Theory of the Universal Wave Function (PDF) which proposes an approach which breaches the classical wall that separates observer and observed. His key insight is, “[h]owever, from the standpoint of our theory, it is not so much the system which is affected by an observation as the observer, who becomes correlated to the system.”

[In his dissertation Everett also addresses a colorful criticism leveled at conventional interpretations of quantum mechanics by Einstein that “he could not believe that a mouse could bring about drastic changes in the universe simply by looking at it.” Everett turns this on its head: “The mouse does not affect the universe - only the mouse is affected.” So much for spooky action at a distance.]

I do think that there are problems hewing to the popular interpretation that of many worlds branching off as observations occur. This is one reason why Sean and others prefer to call MWI “Everettian Quantum Mechanics.” And I would have to admit that I’m not quite sure what meaning to attribute to the ever increasing number of quantum states with which we find ourselves involved as required by the theory. Perhaps they are worlds in some sense, but certainly not the dynamically created universes of the multiverse theories that have captured the attention of string theorists over the last several decades.

In any event, there’s a lot for me to learn here, but I feel like I've finally gotten my arms around a very profound physics question that's been bothering me for a long time.