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One question a lot of athletes have is whether they can work out when they're sick. Obviously, you don't want to lose training time, but on the other hand you don't want to make yourself too sick by training when you should be resting. The conventional wisdom is the "neck" rule (see for instance this article): if your symptoms are above the neck then you can train; if they're below the neck you can't:

David Nieman, Ph.D., who heads the Human Performance Laboratory at Appalachian State University, and has run 58 marathons and ultras, uses the "neck rule." Symptoms below the neck (chest cold, bronchial infection, body ache) require time off, while symptoms above the neck (runny nose, stuffiness, sneezing) don't pose a risk to runners continuing workouts.

This view is supported by research done at Ball State University by Tom Weidner, Ph.D., director of athletic training research. In one study, Weidner took two groups of 30 runners each and inoculated them with the common cold. One group ran 30 to 40 minutes every day for a week. The other group was sedentary. According to Weidner, "the two groups didn't differ in the length or severity of their colds." In another study, he found that running with a cold didn't compromise performance. He concluded that running with a head cold--as long as you don't push beyond accustomed workouts--is beneficial in maintaining fitness and psychological well-being.

The relevant paper is here. Most of the people I know tend to stick to easy distance and avoid hard workouts like intervals. I don't know of any science supporting this theory, though.

This NYT article, sent to me by Eu-Jin Goh, also describes another study that indicates that colds don't impair exercise performance:

The studies began, said Leonard Kaminsky, an exercise physiologist at Ball State University, when a trainer at the university, Thomas Weidner, wondered what he should tell athletes when they got colds.

The first question was: Does a cold affect your ability to exercise? To address that, the researchers recruited 24 men and 21 women ages 18 to 29 and of varying levels of fitness who agreed to be deliberately infected with a rhinovirus, which is responsible for about a third of all colds. Another group of 10 young men and women served as controls; they were not infected.

At the start of the study, the investigators tested all of the subjects, assessing their lung functions and exercise capacity. Then a cold virus was dropped into the noses of 45 of the subjects, and all caught head colds. Two days later, when their cold symptoms were at their worst, the subjects exercised by running on treadmills at moderate and intense levels. The researchers reported that having a cold had no effect on either lung function or exercise capacity.

This actually is a fairly surprising result. Most athletes certainly feel their performance suffers when they're sick. I certainly feel worse training when sick, and while I haven't taken any measurements of lung capacity, I do notice that my heart rate is significantly higher. If anyone has access to the original paper, I'd be very interested in reading it. (Abstract here). Initial impressions: the sample size is pretty small. I'd be interested in seeing a crossover study. What about performance at strength exercises?

I recently read Hanna Rosin's piece in The Atlantic about transgender children. The subjects of the piece are children who, from a very young age (< 5) insist that they are—or want to be—the other gender. Even for parents who are basically cool with the concept of the transgendered, this seems to still require some pretty difficult decisions. My take home points from the article go something like this:

• The current state of sex reassignment (yes, I know that some trans-people prefer the term "gender confirmation surgery", but as far as I know, sex reassignment is still the standard term) technology isn't that great. Certainly, a post-treatment female (i.e., someone who was born male) isn't as much like a biological female as you would like.
• Sex reassignment treatment works a lot better if you haven't gone through puberty yet.
• It seems fairly problematic to let children this yound make judgements about something as irreversible as having their genitals reconstructed. Moreover, according to this Endocrine Society review, a significant fraction of children diagnosed with Gender Identity Disorder (GID) experience spontaneous remission post-puberty.
• There are treatments available which will block/delay puberty, so at least the children are old enough to have a better chance of making their own decisions, though if it's puberty itself that realigns the child's psychological identity with their biological identity, it's not clear that helps as much as you would like. Anyway, if that happens, you can just stop the hormone blockers and let puberty proceed normally.
• The children in question seem much happier when they're allowed to dress and act as the gender they want to be.
• There are some psychological treatments which may (or may not) increase the chance that the child will become happier with their biological identity, but they sound pretty uncool (e.g., encouraging extreme traditional gender roles), and after reading the Atlantic article, I came away with the impression that the treated children weren't that happy as adults. But this seems inconsistent with letting them assume their desired gender roles in the interim.

One more note: some of the children in this article seem to have adopted stereotypical opposite sex behaviors incredibly early (like 2-3 years old.) I don't know what that tells us about how preferences for such behaviors get determined, but it's interesting.

The Times reports that H.M., a name familiar to generations of psych undergrads, has died. H.M. was a patient who underwent surgical treatment for a seizure disorder which left him unable to form new memories (think Memento but without the tattoos and the ultraviolence.) This made him a popular subject for the study of memory. One of the most interesting features of H.M.'s condition was that he could learn some new physical skills without being conscious of it. When presented with the task he would claim never to have tried it before, but would be able to perform them anyway. The Wikipedia article and the Times obit both make good reading.

As I mentioned earlier, Netflix Instant Viewing (and hence the Roku) is pretty heavy on the cheezy 80s TV shows. Mrs. EG and I have been catching up on Forever Knight, the existential tale of a vampire living in Toronto, trying to become human, and making up for his sins by posing as a Canadian cop named Nick Knight (though not that polite, so you can tell he's not really Canadian). Anyway, in the Forever Knightiverse, it seems you can get along OK by drinking cow's blood, so we're back to the situation I alluded to in an earlier post, vampirism as an immortality treatment with some annoying side effects. Given that, it occurs that Mr. Knight would do a lot more good for people by starting a cow blood production operation and saving the lives of the terminally ill by turning them into vampires. Just saying.

Ditzen, Pellegrino, and Vauxhall had an interesting paper in science a few months ago about the insect repellent DEET and its mechanism of action. Their results seem to indicate that a significant fraction of the effect of DDT isn't so much insect repellence as blocking the attractant effect of 1-octen-3-ol, which is present in human breath. The figure below summarizes the observed behavioral results on drosophila:

At high concentrations of DEET and/or when flies can come in direct contact with the DEET, flies are repelled. I.e., they prefer an empty chamber without DEET to one with DEET. If you reduce the concentration of DEET to 10% and cover it with a perforated polypropylene barrier, the repellent effect is eliminated, and the flies end up equally in both vials. However, if you take the same pair of vials (one without DEET and one with DEET) and put food in both of them, then the flies far far prefer the one without DEET.

This is confirmed by direct studies of the fly (drosophila) and mosquito (anopholoes gambiae) sensory systems which show a significantly reduced response to 1-octen-3-ol in the presence of DEET (The other major attractant is CO2, but DEET doesn't seem to have much effect on that.) This kind of explains why DEET has a relatively short range of action: this NEJM article claims 4 cm, while Ditzen et al. claim 38 cm (I can't read either of the original sources) but in either case, it's pretty short. I wonder if part of the issue is that mosquitos are still attracted to other chemicals you're emitting (e.g., CO2) but they get confused when they can't smell the 1-octen-3-ol, so they get close but don't want to actually land on you. What you really want, though, is something that will convince mosquitos they want to be far away from you, not just that they don't want to be near you.

Predicting Human Brain Activity Associated with the Meanings of Nouns
Tom M. Mitchell, Svetlana V. Shinkareva, Andrew Carlson, Kai-Min Chang, Vicente L. Malave, Robert A. Mason, Marcel Adam Just

The question of how the human brain represents conceptual knowledge has been debated in many scientific fields. Brain imaging studies have shown that different spatial patterns of neural activation are associated with thinking about different semantic categories of pictures and words (for example, tools, buildings, and animals). We present a computational model that predicts the functional magnetic resonance imaging (fMRI) neural activation associated with words for which fMRI data are not yet available. This model is trained with a combination of data from a trillion-word text corpus and observed fMRI data associated with viewing several dozen concrete nouns. Once trained, the model predicts fMRI activation for thousands of other concrete nouns in the text corpus, with highly significant accuracies over the 60 nouns for which we currently have fMRI data.

This paper is pretty interesting. Basically, they have measured fMRI activation data for 60 words. So, voxel v has activation level A_v_w for word w. For each word, they have measurements of a bunch of linguistic parameters P_1, P_2, P_3..., etc. They then fit a predictive model for the effect of each parameter on the activation level of each voxel, so for instance you could say that if a word is associated with "sight" (i.e., it appears near "sight" in text corpii) that increases the activation of voxel v by .1 units. This is fairly straightforward regression modelling stuff.

Once you have the model fitted, you can then predict the activation of each voxel for a novel word by taking its linguistic parameter values and plugging them into the model. Their results are actually pretty good. They have a corpus of 60 word/fMRI pairs and they use 58 as a training set and 2 as a test set. They then try to differentiate the two test words by asking which predicted activation pattern is closer. The results are significantly better than chance: mean=.77 for what appears to be arbitrary words and mean=.62 when the words are from the same semantic category (e.g., "celery" and "corn"). Moreover, a significant amount of the error appears to come from head motion by the subjects.

I'm not sure how to interpret this from a scientific perspective. It's a long way from knowing which brain cells are used in processing certain words to knowing how the brain actually processes those words. On the other hand, it's not clear you ned that deep an understanding to build a brain-scanning fMRI gizmo that does something useful. Though we're a long way from that too. Even ignoring the fact that we don't understand the brain well enough, hanging out with your head in a noisy magnet probably isn't a lot of fun.

For some reason I checked out Conservapedia today. Sort of an amazing artifact, if basically insane. It's like—well, it actually is—they want to create a whole alternate reality where the normal rules of intellectual discourse don't apply. Here's the (somewhat famous) article on the kangaroo:

According to the origins theory model used by young earth creation scientists, modern kangaroos are the descendants of the two founding members of the modern kangaroo baramin that were taken aboard Noah's Ark prior to the Great Flood. It has not yet been determined by baraminologists whether kangaroos form a holobaramin with the wallaby, tree-kangaroo, wallaroo, pademelon and quokka, or if all these species are in fact apobaraminic or polybaraminic.

After the Flood, these kangaroos bred from the Ark passengers migrated to Australia. There is debate whether this migration happened over land[6] with lower sea levels during the post-flood ice age, or before the supercontinent of Pangea broke apart[7] The idea that God simply generated kangaroos into existence there is considered by most creation researchers to be contra-Biblical.

Other views on kangaroo origins include the belief of some Australian Aborigines that kangaroos were sung into existence by their ancestors during the "Dreamtime" [8] and the evolutionary view that kangaroos and the other marsupials evolved from a common marsupial ancestor which lived hundreds of millions of years ago.[9] In accordance with their worldviews, a majority of biologists regard evolution as the most likely explanation for the origin of species including the kangaroo.

Uh, yeah. Incidentally, that passage contains links to Baraminology, the study of Biblical kinds. I almost expect there to be a page on the Turtles all the way down theory of cosmology. I was going to try to make a serious argument about this, but it's just laughable.

Incidentally, Mrs. G noted the weird juxtaposition of Pangea and flood theory. Unsurprisingly, there's a footnote pointing to this uh, explanation about how Pangea is compatible with flood theory. In case you're curious, it's that the rate of geologic activity was higher during the flood.

Interesting fact: there's a significant amount of evidence that sleeping on the left hand side as opposed to the right hand side significantly reduce GERD. For instance: Khoury et al. (1999(:

METHODS: Ten patients, three female and seven male (mean age 47.6 yr, range 30-67 yr) with abnormal recumbent esophageal pH <4 on 24-h pH-metry participated. A standardized high fat dinner (6 PM) and a bedtime snack (10 PM) were administered to all patients. GER during spontaneous sleep positions was assessed with a single channel pH probe placed 5 cm above the lower esophageal sphincter (LES) and with a position sensor taped to the sternum. Data were recorded with a portable digital data logger (Microdigitrapper-S, Synectics Medical) and analyzed for recumbent percent time pH <4 and esophageal acid clearance time in each of four sleeping positions. Time elapsed between change in sleeping position and GER episodes was also calculated.

See also Katz et al. (1994), van Herwaarden et al. (2000). The mechanism doesn't appear to be entirely clear, however.

Lutsey, Steffen, and Stevens report study of dietary intake and "metabolic syndrom" (MetSyn), described as "a cluster of cardiovascular risk factor abnormalities associated with increased risk of type 2 diabetes mellitus, cardiovascular disease, and all-cause mortality." Here's what they found:

Background--The role of diet in the origin of metabolic syndrome (MetSyn) is not well understood; thus, we sought to evaluate the relationship between incident MetSyn and dietary intake using prospective data from 9514 participants (age, 45 to 64 years) enrolled in the Atherosclerosis Risk in Communities (ARIC) study.

Methods and Results--Dietary intake was assessed at baseline via a 66-item food frequency questionnaire. We used principal-components analysis to derive "Western" and "prudent" dietary patterns from 32 food groups and evaluated 10 food groups used in previous studies of the ARIC cohort. MetSyn was defined by American Heart Association guidelines. Proportional-hazards regression was used. Over 9 years of follow-up, 3782 incident cases of MetSyn were identified. After adjustment for demographic factors, smoking, physical activity, and energy intake, consumption of a Western dietary pattern (Ptrend=0.03) was adversely associated with incident MetSyn. After further adjustment for intake of meat, dairy, fruits and vegetables, refined grains, and whole grains, analysis of individual food groups revealed that meat (Ptrend<0.001), fried foods (Ptrend=0.02), and diet soda (Ptrend=< 0.001) also were adversely associated with incident MetSyn, whereas dairy consumption (Ptrend=0.006) was beneficial. No associations were observed between incident MetSyn and a prudent dietary pattern or intakes of whole grains, refined grains, fruits and vegetables, nuts, coffee, or sweetened beverages.

Conclusions--These prospective findings suggest that consumption of a Western dietary pattern, meat, and fried foods promotes the incidence of MetSyn, whereas dairy consumption provides some protection. The diet soda association was not hypothesized and deserves further study.

(Full article behind a paywall, but I have sources).

So, working through the actual analysis, it looks like what they did was cut the level of consumption of each pattern or individual food group into quintiles and then compare the relative risks in each quintile. So, for instance, the highest quintile of the Western diet has an 18% (1.03 - 1.37) higher risk of MetSyn than the lowest quintile. At some level, this is good news if you tend to eat an "unhealthy" diet. An 18% increased risk really isn't that much, and you might well be willing to absorb it in order to keep eating stuff you like all the time, especially because the second quartile has a 13% increased risk, so you'd need to make pretty dramatic changes in order to see much improvement.

One question I'm having trouble extracting here is the extent to which the effect of the "Western Diet" is dominated by consumption of meat and fried foods (the only factors tha are significant in this model.) It's certainly possible that you could get away with eating all the sugar you wanted as long as you stayed off the chicken fried steak. On the other hand, it doesn't look like eating your vegetables helps at all.

The other result that's gotten a lot of press here is the association between diet soda consumption and MetSyn (34% in the highest tertile). As the authors say, it's hard to know if this is a cause or an effect, and needs some more study.

Ezra Klein points out that while the US death rate from prostate cancer is more or less the same as in other developed nations, the survival rate is a lot higher because the US screening program is so effective.

Figure from: Cancer Research UK

A natural question to ask at this point is: what's the point of a massive screening program if it doesn't improve the death rate? There's more to the issue here than the cost of the screening, since you need to followup with other tests, eventually culminating in a biopsy, and then treatment isn't fun. And of course it's probably kind of stressful to find out you have prostate cancer, even if it's not eventually going to kill you.