Archive for January, 2009

Jan 30 2009

Some End-Of-The-Week Stupidity

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As far as I know the mortality rate due to ghosts is zero. There are no credibly documented cases of anyone being injured or killed by a ghost. Besides – they are supposed to be immaterial, so how could they harm you? They might make you a bit chilly, or give you a severe case of the willies, but that’s it. I suppose they could frighten a weak-hearted person to death, in which case all we have to fear is fear itself.

So why, then, are people so terrified of ghosts. I admit I have never seen one, so I cannot honestly brag about how I would react, but I think I would be more fascinated than anything else. My primary thought would probably be – where’s my camera?

Why, then, are staff at Derby’s new Royal Hospital so frightened? According to news reports:

There have been dozens of sightings over recent weeks and people are scared witless.

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Jan 29 2009

Dinosaur Fossils and Evolution

Published by under Evolution

Leading up to the 200th anniversary of Darwin’s birth on February 12th, and the 150th anniversary of the publication of the Origin of Species, I will be covering more evolution-related news items. It has long been a favorite scientific topic of mine anyway, so it’s a good enough excuse to focus on evolution.

One of the strongest lines of evidence for the fact that life on earth arose through evolution is the fossil record. I do not think this is the strongest line of evidence, not because it is weak but because the genetic evidence is so remarkably strong. Statistically speaking, the genetic evidence speaks to common descent through branching speciation of all life on earth to such a degree that it approaches certainty.

But the fossil evidence is also impressive, and much more visceral – walking into a museum full of gigantic fossil dinosaurs (or at least their casts) has a coolness factor with which a string of base pairs cannot compete.

Creationists, of course, deny the implications of the fossil evidence. At the extreme end are some young-earth creationists who claim that Satan put the fossils there to test our faith. That unfalsifiable notion is not worth further comment.

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Jan 28 2009

Obama’s UFO

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The interwebbies is full of discussion about the alleged UFO that was filmed by CNN just prior to Obama’s inauguration. You can watch the video here, along with some amusing commentary by a UFO believer.

edit: The Youtube video was removed, so watch this version here.

When I first saw the video my immediate reaction was that this blurry object that flies across the screen was a bird, or perhaps an insect closer to the camera. After looking more closely, and hearing various commentary, I am convinced that these are the most likely explanations – and of the two I think it is most likely a bird.Watch the video carefully. Despite the narrators description that the object moves in a straight line, it is not moving in a straight line at all. It is moving in a sinusoidal wave, which means it is bobbing up and down slightly as it flies. This is exactly how a flapping bird moves through the air (and why I think it’s a bird and not an insect).In fact the narrator mentions that it looks as if some flapping is visible, but he dismisses this as an artifact of the camera. I disagree – I think we are seeing the blurry flapping of wings.

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Jan 27 2009

Yet More Evidence Against a Link Between Thimerosal and Autism

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A new study published yesterday (Monday) in the journal Pediatrics provides more evidence against any link between thimerosal (a mercury-based preservative in some vaccines) and autism or other neurological disorders. This study adds to the large and growing body of scientific evidence for the safety of vaccines, and contradicting the claims of the anti-vaccine movement that vaccines cause autism.

The study is a bit fortuitous in that it was not originally designed to probe this question. Rather, this was a safety and efficacy study of the acellular pertussis vaccine conducted in Italy between 1992 and 1993. But it created a cohort of children who were carefully screened and monitored, and randomized to different exposures to thimerosal. This allowed the researchers to go back 10 years later to survey and examine the children for neurological disorders.

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Jan 26 2009

An fMRI Wrinkle

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Functional magnetic resonance imaging, or fMRI, is an extremely useful new technology (created in 1993 and increasingly used over the last decade) to study brain activity. Like any new and complex tool, however, it is critical to understand how the tool works, especially when interpreting research. A new study published today in Nature may cause fMRI researchers to change how they conduct an interpret their research.

fMRI is an application of regular MRI, made possible by advances in computer processing power and researchers finding new ways to exploit how living tissue responds to a powerful magnetic field. In the case of fMRI it was discovered that blood reacts differently when it is highly oxygenated than when it is less oxygenated. This is because oxyhemoglobin (the form of hemoglobin with oxygen) is diamagnetic, while deoxyhemoglobin (the form of hemoglobin without oxygen) is paramagnetic. Most living tissue (and in fact most stuff) is diamagnetic – in response to a strong external magnetic field it creates a weak opposite magnetic field. In superconductors this property can be exploited to create levitation above a strong magnet. A paramagnetic substance, rather, in response to a strong external magnetic field creates an attractive magnetic field. Unlike ferromagnetic materials (like iron), diamagnetic and paramagnetic substances lose their magnetic field as soon as the external field ends – they are not permanent or long-lasting.

All of this means that oxygenated and less oxygenated blood behave differently in the magnetic field of an MRI and this differential response can be exploited to image relative arterial blood flow to different parts of the brain. An entire branch of neuroscientific research has sprung up over this fact – using fMRI to see which parts of the brain are active when subjects are asked to perform a specific task, when they are exposed to external stimuli, or in different disease states.

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Jan 23 2009

Some Follow Up On Migraines

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Yesterday I wrote about a new Cochrane review of acupuncture and migraines. The most significant result of the review was that published studies show no difference between “real” acupuncture and “sham” acupuncture. This is the part of trials that can be blinded – well, single-blinded at least (the subject does not know which is real vs sham, but the acupuncturist does). This blinded data is negative, indicating that it does not matter where you stick the needles, which is a strong indication that the underlying philosophy of acupuncture is false. Further, now that acupuncture studies are being done with placebo acupuncture – opaque sheaths and dull needles that do not penetrate the skin, allowing for double-blind studies – these are also coming out negative.

Therefore, I think it is reasonable to conclude from the literature that it does not matter where you stick acupuncture needles, or even if you stick them. Therefore, any observed benefit must be either: 1) an artifact of the study design (i.e. placebo effects); or 2) a result of other things that are happening in association with the acupuncture treatment.

Several points were raised in the comments I want to address in some detail. Further, there are many questions about migraines, and since migraines make up a significant portion of my clinical practice I can clear up some of the confusion as well.

Migraines

First some background on migraines.   Migraines are a specific kind of primary headache, meaning that the headache is the disorder and is not secondary to an underlying problem, like a brain tumor. Migraine are variable in their presentation, and so are defined as having some of a list of symptoms. These include unilateral (one-sided), throbbing, can be triggered by various things, and associated with nausea, vomiting, and sensitivity to light, sound, and strong odors. Migraines can also occur with an aura, which is a neurological symptom occuring before or during the headache, most commonly visual changes like dark spots (scotoma) or flashing lights (visual fortifications).

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Jan 22 2009

Through the CAM Looking Glass

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A newly published systematic review of a controversial anti-migraine drug, migrostat, shows that it works no better than placebo. The review for the Cochrane Collaboration looked at 33 trials, involving a total of 6,736 patients. Those patients treated with migrostat had a reduction of frequency and severity of migraines of about 30%, but this was no better than the placebo group which experienced a similar reduction (there was a “slight” advantage for tension headaches, likely noise in the randomness) – a response rate typical of placebo treatment for subjective symptoms.

The lead author of the review,  Dr. Jacob Bayous, who works for the Pharmaceutical Industry Research Center, is quoted as saying:

“Much of the clinical benefit of migrostat might be due to non-specific effects and powerful placebo effects, meaning selection of specific chemical constituents may be less important than industry proponents have traditionally argued.”

Despite the fact that this review clearly shows that migrostat is no better than placebo – the standard scientific interpretation of which is that it does not work – industry proponents (who are eager to get FDA approval for migrostat) claim that the drug works – “as placebo.” They argue that migraine sufferers still find relief from taking migrostat, and that relief is valuable, even if it is only an effect of the “power of the mind.”

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Jan 20 2009

Stem Cells for Stroke

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Dr. Keith Muir is leading a trial at the Southern General Hospital in Glasgow that is about to test stem cells as a possible therapy in stroke. As reported by the BBC, the trial is set to enroll 12 subjects and will last for two years. While this will be far from a definitive trial, it will explore the basic safety and potential of this approach.

Strokes occur due to lack of blood flow to a part of the brain. Those brain cells are injured – those at the core of the stroke die while those around the periphery (which is usually much larger in volume than the core), which are getting some blood flow, may or may not survive. About a third of stroke patients recover either fully or nearly so, while the rest either die or suffer permanent neurological deficits. The symptoms of a stroke depend upon what part of the brain is damaged.

Dead brain cells do not come back. Initial recovery results from damaged but not dead neurons recovering their function. After that, deficits are due to dead brain cells and are considered permanent. However, further recovery is possible (although slow – months to years) due to the brain’s plasticity. The brain can rewire around damaged section, and form new pathways. In addition, healthy cortex can take over the lost functions or compensate for them to some degree. This takes a great deal of time and effort, which is part of the function of the long course of rehabilitation that often takes place following a stroke.

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Jan 19 2009

Louisiana, We Have a Problem

Published by under Evolution

In my recent post on the battle between science and creationism, I noted that the current strategy of the intelligent design (ID)/creationism movement is to push for academic freedom. They don’t really care about academic freedom, they just want to erode academic quality standards so as create a back door through which they can squeeze their religious beliefs into science classrooms. This strategy is playing out in Louisiana.

Last year Louisiana governor Bobby Jindahl signed into law an academic freedom bill that was part of this strategy. Now, just last week, the state’s Board of Elementary and Secondary Education passed the Louisiana Science Education Ac. Casey Luskin, one of the worst apologists for anti-science over at the ID “think tank”, the Discovery Institute, characterized this bill as a “victory for Louisiana students and teachers.”  If Luskin in happy with this bill, we should be very worried. Continue Reading »

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Jan 15 2009

I’ll be on NPR

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Quick note for those who are interested, I will be interviewed on NPR Friday morning 9:30-10:30 Eastern time. The topic will be about dualism and the evolution of human consciousness. They tell me that Michael Egnor may also be on – should be interesting.

Update!

The interview went well, it was a 1 on 1 for about an hour. It was being recorded for future broadcast. I was told it will come out around Darwin’s birthday (Feb 12th) either on Morning Edition or All Things Considered.

As soon as they let me know exactly when I will post another update.

Urgent Update:

This is actually unrelated, but I was asked to be on JPR, a local Oregon NPR affiliate, right now!!!.

That is – 12:00-1:00pm Eastern Today.

You can stream live from here: http://www.ijpr.org/ (go to The Jefferson Exchange under News). Here is the link to the show description: http://www.ijpr.org/ProgramGuide.asp?StationID=3

Download the podcast here (http://www.npr.org/rss/podcast/podcast_detail.php?siteId=5593976)  – my interview is the second hour.

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