The discovery, rediscovery, and re-rediscovery of computed tomography

Note: This post is my contribution to The Giant’s Shoulders #2, to be held at The Lay Scientist. I thought I’d cover something a little more recent than my previous entries to the classic paper carnival; in truth, I need a break from translating 30-page papers written in antiquated German/French!

One of the fascinating things about scientific progress is what you might call its inevitability. Looking at the history of a crucial breakthrough, one often finds that a number of researchers were pushing towards the same discovery from different angles. For example, Isaac Newton and Gottfried Leibniz developed the theory of calculus independently and nearly simultaneously. Another example is the prehistory of quantum mechanics: numerous experimental researchers independently began to discover ‘anomalies’ in the behavior of systems on the microscopic level.

I would say that the development of certain techniques and theories become ‘inevitable’ when the discovery becomes necessary for further progress and a number of crucial discoveries pave the way to understanding (in fact, one might say that this is the whole point of The Giant’s Shoulders). Occasionally it turns out that others had made a similar discovery earlier, but had failed to grasp the broader significance of their result or were missing a crucial application or piece of evidence to make the result stand out.

A good example of this is the technique known as computed tomography, or by various other aliases (computed axial tomography, computer assisted tomography, or just CAT or CT). The pioneering work was developed independently by G.N. Hounsfield and A.M. Cormack in the 1960s, and they shared the well-deserved 1979 Nobel Prize in Medicine “for the development of computer assisted tomography.” Before Hounsfield and Cormack, however, a number of researchers had independently developed the same essential mathematical technique, for a variety of applications. In this post I’ll discuss the foundations of CT, the work of Hounsfield and Cormack, and note the various predecessors to the groundbreaking research.

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Posted in History of science, Physics | 13 Comments

The Montauk monster: a dead raccoon, after all…

Over the past week we’ve been treated to a barrage of news stories about a mysterious carcass which washed up on the beach of Montauk, Long Island, on July 13th.  Dubbed “The Montauk monster”, it even rated a video bit on CNN.

Alas, the ‘monster’ has been identified, and is none other than the decayed remains of a raccoon that had spent lots of time in the water.  Details can be found at Tetrapod Zoology.

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Posted in ... the Hell?, Animals | 10 Comments

Heart-Shaped Box, by Joe Hill

As I’ve noticed previously, I took a multi-year hiatus from reading horror novels, in large part because I couldn’t separate out the gems from the trash in the new horror releases. Since I decided to blog about horror fiction, among other things, I’ve been taking another look at the current crop of horror authors, and I’ve been pleasantly surprised.

The most recent read I’ve undertaken is Heart-Shaped Box (2007), by Joe Hill. Hill is a newcomer to the horror field, and has only one other book, 20th Century Ghosts (2005), a collection of short stories. I’ll be picking up the latter in the near future, because Heart-Shaped Box was an excellent book that does the genre proud.

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My photo in Parachutist Magazine!

I’m famous!  The balloon jump I did a couple of months ago, with video and pictures, made it as a photo in Parachutist, the official USPA (United States Parachute Association) publication.  Here’s the relevant page:

That’s me leaping out in the upper left corner!  I’ve demurely blocked out my name in the caption, even though my pseudonym isn’t a particularly big secret these days.

My plan to penetrate all sorts of media is proceeding briskly!  I’ve been quoted in newspapers, books, journals, and now magazines.  All that’s left is to get myself on the radio and television, preferably without doing something horrible!   😛

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15 days until The Giant’s Shoulders #2!

This seemed like as good a time as any to remind readers that we’re 15 days out before the deadline of The Giant’s Shoulders #2, to be held at The Lay Scientist.  Entries can be submitted through blogcarnival.com, or sent directly to the host.  I’ll keep pestering and reminding people about the carnival until it takes on a sufficient life of its own…

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Feeling history in your bones: Brühl’s Terrace

Via OhGizmo!, we find that an exhibit exists (or did exist) on Brühl’s Terrace in Dresden, Germany, which allows one to experience the simulated sounds of the devastating 1945 bombing of the city simply by resting oneself against a railing on the terrace in the appropriate manner (image from OhGizmo!):

The technology, evidently referred to as ‘touched echo’, is more descriptively known as bone conduction technology, and relies on the transmission of sounds directly to the inner ear through vibrations in the skull, rather than vibrations in the eardrum.  The inner ear responds to vibration of the fluid contained within it, and in principle anything which produces such a vibration will be interpreted as ‘sound’.

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H. Rider Haggard’s She

Before Indiana Jones, there was Allan Quatermain, elephant hunter and adventurer/explorer of Africa. Quatermain was the creation of H. Ridger Haggard (1856-1925), and was featured in the novels King Solomon’s Mines and Allan Quatermain. Haggard’s work was informed by his own experiences working for the British government in one of their South African colonies, and his works are still in print to this day, though not as widely read as they once were.

I recently finished reading Haggard’s other famous adventure/romance, She (1887), in preparation for another lengthy survey of weird fiction, and I thought I’d share some thoughts on the novel.

The “She” of the title refers to a legendary white queen of an isolated African tribe, though her full title is, “She who must be obeyed” (she’s also named Ayesha, but that’s not nearly as impressive sounding). The novel tells the tale of a trio of adventurers who risk life and limb to travel in search of her.

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Posted in Adventure fiction, Fantasy fiction | 7 Comments

Freezing images in an atomic vapor!

ResearchBlogging.org
I thought I’d step out of my comfort zone and specific field of expertise for once and do a post on some interesting quantum optics. In a June issue of Physical Review Letters, an Israeli research group experimentally demonstrated the ability to store and retrieve optical images in an atomic vapor using so-called ‘electromagnetically induced transparency’, a purely quantum-mechanical effect. Researchers have previously demonstrated the ability to ‘freeze’ light pulses in an atomic medium, but this is the first time to my knowledge that a structured two-dimensional image has been given the same treatment. To fully describe the research and its significance, however, we need to say a little bit about how atoms and molecules absorb and emit light.

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Posted in Optics, Physics | 5 Comments

No surprise: Girls just as good at math as boys

The title says it all: via CNN, we learn that a comprehensive study published today in Science (for those with access, the article can be read here) shows that girls perform just as well as boys in mathematics. This study is the largest and most detailed of its kind, comparing 7 million children from grades 2 to 11. The only weakness I can see at first glance is that the study used “No Child Left Behind” standardized test scores as its metric, and standardized testing is rather limited in its ability to capture true aptitude.

The results aren’t surprising, though; in my personal teaching experience I’ve typically found that girls do better than boys in physics. This is a limited sample, and skewed by the depressingly small number of women taking physics classes, but I’ve never had any doubts of women’s ability to succeed in mathematical and technical disciplines.

A good example of this is Emmy Noether (1882 – 1935), who in 1918 published what is now known as Noether’s theorem, a general and far-reaching theorem which demonstrates the link between symmetries in physical systems and conservation laws. Conservation of momentum, for instance, is connected with the fact that the laws of physics do not depend on position. Noether’s obituary was written in the New York Times by no less a distinguished mathematician than Einstein himself.

Update:  Via Uncertain Principles, I learn that, as always, the Onion has the funniest take on a serious subject…

Posted in Science news | 36 Comments

Graham Masterton’s The 5th Witch

I finally got a chance to read one of Graham Masterton’s most recent novels, The 5th Witch, and I thought I’d share some thoughts about it!  (In fact, there’s an even more recent novel, House of Bones, which I’m going to get ASAP.)

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Posted in Horror | 25 Comments