Just for fun: Giraffe fight club

Ah, the peaceful majestic giraffe... and then there's this. 




Filmed on Safari in Tanzania. If you want to know more about giraffes' neck-bashing fighting techniques and how they may relate to the evolution of the species, this post by Brian Switek is well worth a read.

A clue to acne development

Ever wonder why some of your friends sailed through puberty without a blemish while you were buying stock in acne medications? Researchers from UCLA, led by Sorel-Fitz-Gibbon and Shuta Tomida, may have the answer. Although nearly everyone’s skin is populated by Propionibacterium acnes (the pathogen thought to be responsible for acne), not everyone has the same strain of these bacteria. Some versions of P. acnes may actually be beneficial.

The scientists compared the skin microbiome on the noses of 49 acne sufferers and 52 clear-skinned individuals. For each subject, the vast majority of the bacteria present were of the species P. acnes. Everyone had plenty of these little buggers, and clear-skinned people had the same number as acne patients. However, not all the P. acne had the exact same genotype. The researchers identified six strains that were present in only one group, five only in acne sufferers and one that was only found on the unblemished.

At this point, it’s not clear how P. acnes initiate the development of acne. This new data could mean that some strains are virulent whereas others are protective of the skin. This is certainly true of many species of bacteria, for which only certain strains are dangerous (think MRSA). If true for P. acnes, dermatologists might do well not to try to strip their patients’ faces of bacteria but rather to encourage the growth of helpful strains.

Fitz-Gibbon, S., Tomida, S., Chiu, B., Nguyen, L., Du, C., Liu, M., Elashoff, D., Erfe, M., Loncaric, A., Kim, J., Modlin, R., Miller, J., Sodergren, E., Craft, N., Weinstock, G., & Li, H. (2013). Propionibacterium acnes Strain Populations in the Human Skin Microbiome Associated with Acne Journal of Investigative Dermatology DOI: 10.1038/jid.2013.21.

Motion Magnification

Scientists at the Massachusetts Institute of Technology, led by Hao-Yu Wu, have developed an algorithm to magnify tiny changes and motions. The result was a type of motion magnification they call 'Eulerian Video Magnification'. This is one case where a video is definitely worth a thousand words, so I’ll let author William Freeman shows us the possibilities:

As stated in the video, the algorithm can be used with any video, and computation time is only a few minutes. The code will be offered for free for non-commercial usage on the project web site. In conjunction with this, Quanta Research Cambridge has created a site where users can experiment with their own or provided videos. What else might the technology be used for? One suggestion was to use the algorithm in real time to detect a 'tell' in poker players. I’m sure you can think of even better uses.

Hat tip: Lindsey Muscato.

Wu, H., Rubinstein, M., Shih, E., Guttag, J., Durand, F., & Freeman, W. (2012). Eulerian video magnification for revealing subtle changes in the world ACM Transactions on Graphics, 31 (4), 1-8 DOI: 10.1145/2185520.2335416.

Is there hope for preventing celiac disease?

Celiac disease is an autoimmune disorder in which the introduction of gluten (a protein found in wheat and other grains) precipitates the truncation of the small intestinal villi. This results in a host of unpleasant symptoms, not least of which is the inability to properly absorb nutrients. Once diagnosed with this condition, the only remedy is to avoid all products containing gluten, an expensive, time consuming and sometimes unpalatable option. Because of this, Swedish researchers led by Anneli Ivarsson and Anna Myléus of Umeå University are seeking a way to prevent people from getting the disease in the first place.

The scientists compared two groups of children, each numbering several thousand. The first had been born in 1993, the middle of a ‘celiac epidemic’ in Sweden in which unusually large numbers of children had been diagnosed with the disorder. The second were born in 1997, after the epidemic had subsided. All the children were tested for celiac at age twelve. Sure enough, about 30% more kids had celiac in the first group than in the second.

So what was different about the two groups of children? From 1982 to 1996, parents were advised to postpone supplementing their infants’ diets with gluten-containing foods until the babies were six months old. In 1996, that recommendation was changed to four months of age. The celiac epidemic in Sweden lasted from 1984 to 1996. Could this be a coincidence? Certainly, and more investigation must be done in order to prove that this correlation is in fact a causation. However, the authors feel that early introduction of gluten in conjunction with continued breastfeeding may stave off the development of celiac disease. I’m sorry to say that I'm a bit more skeptical myself.

For one thing, there were minimal actual feeding differences, as remembered by the parents, between the two groups. The children in the 1993 cohort had been breastfed for an average of seven months versus nine months for the later group of children. Gluten was introduced to both groups at about five months of age. The authors contend that the parents might not remember exactly what they had done twelve years earlier, a valid point, but one that could work against them just as much as it could for them. As things stand, the surveys don’t highlight any great differences in infant feeding practices. 

Second, the prevalence of celiac disease did not go down to zero in the 1996 cohort. Just over two percent of those kids had the disorder, which is still a fairly high number. Even if the parents of the second group had followed the authors’ recommendations, it wasn’t a panacea. Then again, possibly reducing the risk of your child developing celiac disease by 30% is nothing to scoff at.

From personal experience, I know that it’s not always possible to convince an infant to follow the feeding plan you’ve designed. I’m not sure this data is worth battling with a child over, but I’m neither an expectant mother with a history of celiac disease, nor a doctor. As always with information gleaned from this blog, check with your medical professional before deciding on any health practices.


Ivarsson, A., Myleus, A., Norstrom, F., van der Pals, M., Rosen, A., Hogberg, L., Danielsson, L., Halvarsson, B., Hammarroth, S., Hernell, O., Karlsson, E., Stenhammar, L., Webb, C., Sandstrom, O., & Carlsson, A. (2013). Prevalence of Childhood Celiac Disease and Changes in Infant Feeding PEDIATRICS, 131 (3) DOI: 10.1542/peds.2012-1015.

The female protective effect in autism

It hasn’t escaped the notice of autism researchers that boys are far more likely to have autism spectrum disorders (ASD) than are girls. In fact, the ratio is something like four afflicted males for every female. This could be because boys are at particular risk for some reason or that girls have some sort of protection from ASD. After comparing almost 10,000 pairs of dizygotic (non-identical) twins, Elise Robinson of Harvard Medical School and her colleagues concluded that when it comes to ASD, there is a ‘female protective effect’.

As the name ‘autism spectrum’ implies, there is huge range of behaviors and symptoms associated with the disease. Individuals can have varying degrees of each trait and different combinations of traits. This no doubt reflects the fact that whole suites of genes that have been implicated with ASD, with similarly afflicted individuals having completely different genotypes and environmental histories. Nevertheless, family members of people who test high for autistic behaviors are more likely to display such behaviors themselves. Here’s where the twins come in.

The researchers argued that if there were a female protective effect, then it would require more drastic genetic changes in girls than in boys to result in the same degree of autistic behavior. In other words, a girl with autism would have a greater number of genetic changes, on average, than a boy with autism. That being the case, there’s a greater chance that a girl’s siblings, who share half her DNA, would also be impaired than a boy’s siblings. This would be particularly true of twins who shared the same womb environment.

To be clear, we already know that ASD is largely inheritable and that the siblings of children with ASD are more likely to have the disorder themselves. The question is whether there’s a difference between the siblings of boys and the siblings of girls with ASD. Short answer: yes there is. The fraternal twins of girls who scored at the top 10% for ASD traits were 38% more likely to also score that high than were the twins of boys.

If there is a female protective effect, we don’t yet know what it is. However it functions, it only further complicates the morass that is ASD genetic studies since researchers now have to take gender into account when looking for genetic causes. Still, anything that furthers our understanding of this disorder is a good thing.

Elise B. Robinson, Paul Lichtenstein, Henrik Anckarsäter, Francesca Happé, & Angelica Ronald (2013). Examining and interpreting the female protective effect against autistic behavior Proceedings of the National Academy of Sciences of the United States of America : DOI:10.1073/pnas.1211070110.

Just for fun: Smarter every day

Looking for another YouTube science series?  You might enjoy Smarter Every Day, put together by intrepid investigator Destin.

Here's one offering, full of incredible slo-mo of beautiful Amazon parrots.

An hour of exercise won't save you from the perils of sitting

Almost three years ago, I wrote that sitting can kill you. You may have been hoping that the damage done by sitting could be offset by doing some strenuous exercise everyday. I’m afraid not. A new study by Bernard Duvivier and his colleagues from Maastricht University Medical Centre shows that even an hour of vigorous exercise can’t compensate for spending the rest of the day in a chair.

The researchers recruited 18 volunteers to participate in three movement regimens, each lasting four days. In random order, people were asked to sit for fourteen hours/day (sitting), to sit for thirteen hours per day but vigorously pedal a stationary bike for one hour each day (exercise), or to walk for four hours and stand for two hours (minimal intensity). The last two protocols resulted in the same daily energy expenditure. After completing each four-day cycle, the subjects took a ten-day break before moving on to the next regime.

All participants spent the entire four days of each phase hooked up to monitors that measured both their energy expenditure and whether they were sitting, lying, standing or active. They were also asked to keep a food diary and to consume the same number of calories during each movement protocol, though their choices were not otherwise restricted. Finally, the volunteers were given stopwatches to remind them to record time spent sitting, standing or walking at fifteen minute intervals.

You can see the breakdown of the time spent on each activity below:

Graphical overview of time spent in different activity categories (sleeping, sitting, standing, cycling and walking) in the three regimes followed by the participants.

doi:10.1371/journal.pone.0055542

On the morning of day five, after completing each four-day activity protocol, fasting blood samples were taken from each participant. Insulin and plasma lipid levels (cholesterol and triglycerides) did not differ between the sitting and exercise regimes. In contrast, levels of these molecules were improved after the minimal intensity protocol. The differences were not great, but consistent and could have implications for people hoping to stave off type II diabetes or cardiovascular disease.

To be clear, these data do not compare the benefits of vigorous versus low-intensity exercise. Rather, the experiments highlight the health differences between more sitting and less sitting. As expected, less sitting is better. More to the point, one hour of intense exercise per day does not change one’s blood profile. If you want to avoid the detriments of sitting, you’ll have to spend a large part of the day on your feet.


Duvivier, B., Schaper, N., Bremers, M., van Crombrugge, G., Menheere, P., Kars, M., & Savelberg, H. (2013). Minimal Intensity Physical Activity (Standing and Walking) of Longer Duration Improves Insulin Action and Plasma Lipids More than Shorter Periods of Moderate to Vigorous Exercise (Cycling) in Sedentary Subjects When Energy Expenditure Is Comparable PLoS ONE, 8 (2) DOI: 10.1371/journal.pone.0055542.