As a group, dinosaurs were certainly well-ornamented animals. Horns, spikes, crests, plates, sails, clubs and other strange structures marked the bodies of many dinosaurs, but figuring out why these dinosaurs had these structures in the first place has often been difficult to figure out. Numerous hypotheses for different structures have been proposed over the years. [...]... Read more »
Padian, K., & Horner, J. (2010) The evolution of ‘bizarre structures’ in dinosaurs: biomechanics, sexual selection, social selection or species recognition?. Journal of Zoology. DOI: 10.1111/j.1469-7998.2010.00719.x
Three-dimensional models of hominoid skulls used in the study - (a) Hylobates lar; (b) Pongo pygmaeus; (c) Pan troglodytes; (d) Gorilla gorilla; (e) Australopithecus africanus; (f ) Paranthropus boisei; (g) Homo sapiens. They have been scaled to the same surface area, and the colors denote areas of stress (blue = minimal stress, pink = high stress). From Wroe et al, 2010.
It is all too easy to think of human evolution in linear terms. From our 21st century vantage point we can look back through Deep Time for the first glimmerings of the traits we see in ourselves, and despite what we have come to know about the undirected, branching pattern of evolution, the origin of our species is often portrayed as a slow rise from the ape in which brains eventually overtook brute strength. One of the most prominent examples of this was modifications made to our jaws. It has been widely assumed that, compared to apes and our extinct hominin relatives, we have relatively weak jaws - why should we need to exert heavy bite forces if our lineage developed tools to process food before it entered our mouths? It was our relatives among the robust australopithecines - namely Paranthropus - which obviously developed the strongest jaws, but a new study just published in the Proceedings of the Royal Society B questions these long-held assumptions.
As outlined in the introduction of the paper by Stephen Wroe, Toni Ferrara, Colin McHenry, Darren Curnoe, and Uphar Chamoli, the hypothesis that our species has a diminished bite force has primarily been based upon the study of other, obviously heavier-jawed hominins. On the surface this would seem to make sense - our jaws are nowhere near as robust as those of those of the multiple species of Paranthropus - yet our teeth seem well-suited to withstanding heavy bite forces. Among living apes, for example, we have the thickest amount of enamel, one of several features we posses which are consistent with the ability of teeth to withstand strong bites. Some have argued that these features are holdovers from when our prehistoric ancestors required stronger bites to process tough foods, but the team behind the new paper decided to create a detailed test which compared the bite mechanics of our species to some of our close hominin and hominid relatives, both living and extinct. Read the rest of this post... | Read the comments on this post...... Read more »
Inside the human body are millions of miniature machines, the gatekeepers of the electrical impulses that keep our hearts beating and our minds thinking. They’re called ion channels; portals that allow small ions such as sodium, potassium, calcium, and chloride, to pass in or out of cells. A simple responsibility, with a complex and crucial [...]... Read more »
Khalili-Araghi F, Jogini V, Yarov-Yarovoy V, Tajkhorshid E, Roux B, & Schulten K. (2010) Calculation of the gating charge for the Kv1.2 voltage-activated potassium channel. Biophysical journal, 98(10), 2189-98. PMID: 20483327
Whose Time do we live in? Time zones have set standards in keeping with longitudinal boundaries so that we share a clock experience that is often managed by an urban center. I am not the first to note, however, that these standards of Time overlook local, social definitions of Time. Though these local definitions persist, they are not generally the norm adhered to when individuals interact both
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Schieffelin, B. (2002) Marking Time: The Dichotomizing Discourse of Multiple Temporalities. Current Anthropology, 43(S4). DOI: 10.1086/341107
Goal setting is a funny thing. Like many of you, I’m sure, I’ve had a long and checkered relationship with it. I’ve gone back and forth, was a big fan, hated it, went back to goal setting again. What is it that fascinates and repels about goal setting? I set out to look at some [...]... Read more »
LATHAM, G., & LOCKE, E. (2006) Enhancing the Benefits and Overcoming the Pitfalls of Goal Setting. Organizational Dynamics, 35(4), 332-340. DOI: 10.1016/j.orgdyn.2006.08.008
Bora at A Blog Around the Clock posted a well written piece about expertise in journalism yesterday. He describes a division of experts and generalists; obviously the experts are those who have spent years studying a specific topic and understand … Continue reading →... Read more »
Kruger J, & Dunning D. (1999) Unskilled and unaware of it: how difficulties in recognizing one's own incompetence lead to inflated self-assessments. Journal of personality and social psychology, 77(6), 1121-34. PMID: 10626367
As usual, the 2010 Jahrbuch Archäologie Schweiz vol. 93 includes a list of newly discovered and excavated sites. It is no surprise that the number of Palaeolithic and Mesolithic sites discovered or investigated in 2009 is relatively low in comparison to the number of sites from most later prehistoric, roman and medieval periods. The figure [...]... Read more »
Huber, R. . (2010) Neue Territorien in Sicht! Wildbeutergesellschaften der Alt- und Mittelsteinzeit. Archäologie Schweiz, 33(2), 15-21. info:/
Regular readers of these pages will recall previous articles on the discoveryof brown adipose tissue in adult humans.
Brown adipose tissue or BAT is specifically designed to turn calories into heat, thereby significantly affecting metabolic rate.
The current theory is that people who have more BAT, are more obesity resistant and can better handle excess calories. It [...]... Read more »
Tan DX, Manchester LC, Fuentes-Broto L, Paredes SD, & Reiter RJ. (2010) Significance and application of melatonin in the regulation of brown adipose tissue metabolism: relation to human obesity. Obesity reviews : an official journal of the International Association for the Study of Obesity. PMID: 20557470
Have you ever tried to get into the Apple app store? Not as a consumer, but as a developer, I mean? Apparently, it’s pretty tough (just ask the guys from Opera or Wobble iBoobs!). App stores are all different with respect to their associated operating system, development language, the policy of approval and profit sharing [...]Post from: David Bradley's Sciencetext Tech TalkApp store communities
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Bong Gyou Lee, Gun Hee Lee, Yong Ho Shim, & Ajin Choi. (2010) Let developers run into the app store by lowering the barrier-to-entry. Int. J. Electronic Finance, 4(3), 201-220. info:/
In this video, Science in Seconds looks at the world's first picture of a molecule, taken by IBM researchers in 2009 and published in Science Magazine.... Read more »
Gross, L., Mohn, F., Moll, N., Liljeroth, P., & Meyer, G. (2009) The Chemical Structure of a Molecule Resolved by Atomic Force Microscopy. Science, 325(5944), 1110-1114. DOI: 10.1126/science.1176210
Do people construct meaning through the language they use? And if they do, should we be listening more carefully to our client's words and to our own?... Read more »
Atkinson, R. (1999) Discourses of partnership and empowerment in contemporary British urban regeneration. Urban Studies, 36(1), 59-72. DOI: 10.1080/0042098993736
Coupland, C. (2004) Career definition and denial: A discourse analysis of graduate trainees' accounts of career. Journal of Vocational Behavior, 64(3), 515-532. DOI: 10.1016/j.jvb.2003.12.013
TcR interacting with artificial membrane1
Why does autoimmune disease (sometimes) follow viral infection?2
It’s a pretty well-known phenomenon, but a definite answer isn’t yet known — and of course there may not be a single answer, there may be multiple causes. We know that many autoimmune diseases seem to be triggered by some sort of infection [...]... Read more »
McGargill MA, Mayerova D, Stefanski HE, Koehn B, Parke EA, Jameson SC, Panoskaltsis-Mortari A, & Hogquist KA. (2002) A spontaneous CD8 T cell-dependent autoimmune disease to an antigen expressed under the human keratin 14 promoter. Journal of immunology (Baltimore, Md. : 1950), 169(4), 2141-7. PMID: 12165543
Ji, Q., Perchellet, A., & Goverman, J. (2010) Viral infection triggers central nervous system autoimmunity via activation of CD8 T cells expressing dual TCRs. Nature Immunology, 11(7), 628-634. DOI: 10.1038/ni.1888
That's what the findings of a recent paper that concluded 4 popular diets were deficient in micronutrients would state.The paper in question took a look at micronutrient intakes if a person were to follow Atkins, South Beach, DASH or the Best Life diets, and from the very first sentence I knew it was going to be a tough read, "Research has shown micronutrient deficiency to be scientifically linked to a higher risk of overweight/obesity and other dangerous and debilitating diseases"Oh really? I guess it's a zinc deficiency that's leading people to consume more calories than ever before.This read became doubly painful as I had to then read the reference that he was using to support his assertion that micronutrient deficiency and obesity are causally linked, "Micronutrient deficiency has been shown to cause an 80.8% increase in the likelihood of becoming overweight or obese"It was a study published in the journal Economics and Human Biology entitled, Micronutrient deficiency and the prevalence of mothers' overweight/obesity in Egypt and without spending too much time on that study which was also poorly designed, let me simply point out that data collected on a small sample of mothers in Egypt who were subdivided into the poor and the extremely poor, does not even if true, automatically extrapolate to the rest of the world except by authors stretching to find references to help make their papers seem more important.Back to this paper, the author indeed demonstrates that following the aforementioned 4 diet plans people won't meet their micronutrient RDIs. What he didn't bother mentioning was that unless you're eating obesity inducing volumes of foods, regardless of what you're putting in your mouth, you're probably not going to meet your micronutrient RDIs and so really, if you're worried about micronutrients you should be on a basic multivitamin whether you're on a marquee diet or not. Instead the author makes this statement, "The implications of this study are significant and far-reaching.""Consequently, with global obesity being a very real and serious condition it should be of some concern to the millions of individuals worldwide, following one of this study’s four popular diet plans, or similar, using whole food alone, that based on the findings of this study, micronutrient deficiency is inevitable."Scary sounding, but more nutritional fear mongering than truly concerning and an issue certainly not unique to dieters.Ultimately this was a non-study. It was a completely expected result which the author spectacularized by inventing a causal link with obesity where there is none.So imagine my non-surprise when I got to the end of the study and read this, "JBC (the author) is the CEO of Calton Nutrition, a private corporation that researches the causation and prevalence of micronutrient deficiency worldwide. Due to the results of its research Calton Nutrition is in the process of developing a multivitamin"Peer review, shmeer review.(The most important (and not discussed) part of the study? If the author's calculations are correct the DASH diet, when followed, leads people to consume 2,200 calories - enough to cause weight gain for a woman with a healthy body weight.)Calton, J. (2010). Prevalence of micronutrient deficiency in popular diet plans Journal of the International Society of Sports Nutrition, 7 (1) DOI: 10.1186/1550-2783-7-24
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Calton, J. (2010) Prevalence of micronutrient deficiency in popular diet plans. Journal of the International Society of Sports Nutrition, 7(1), 24. DOI: 10.1186/1550-2783-7-24
Jeremy Gunawardena pointed me to this terrific paper that results from a collaboration between Bruce Walker’s and Arup Chakraborty’s groups (Košmrlj et al. Effects of thymic selection of the T-cell repertoire on HLA class I-associated control of HIV infection. Nature 465 350-4. PMID: 20445539). On reading it, I realized that I had heard Arup present the work at the ICSB 2009 conference; for me, it was one of the highlights of the meeting.... Read more »
Kosmrlj A, Read EL, Qi Y, Allen TM, Altfeld M, Deeks SG, Pereyra F, Carrington M, Walker BD, & Chakraborty AK. (2010) Effects of thymic selection of the T-cell repertoire on HLA class I-associated control of HIV infection. Nature, 465(7296), 350-4. PMID: 20445539
Most physicians of my age only witnessed summative evaluations during their medical education. You studied your stuff and did an exam for which you could fail or not, go or no go. Our exams were tests aiming to summarize learning up to that point. Today most med students are evaluated with formative evaluation. Continuous evaluations [...]
Related posts:Medical Education Evaluated With Twitter
Twitter, Doctors, Hospitals and Medical Education
Twitter during Lectures part 2
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Stefan Stieger, D.Sc., & Christoph Burger. (2010) Let’s Go Formative: Continuous Student Ratings with Web 2.0 Application Twitter. CYBERPSYCHOLOGY, BEHAVIOR, AND SOCIAL NETWORKING, 163-167. info:/10.1089/cyber.2009.0128
Roll up, roll up, ladies and gentlemen, Impact Factor Boxing is here again. As with last year (2009), these metrics are already a year out of date. But this doesn’t stop many people from writing about impact factors and it’s been an interesting year  for the metrics used by many to judge value of [...]... Read more »
Rizkallah, J., & Sin, D. (2010) Integrative Approach to Quality Assessment of Medical Journals Using Impact Factor, Eigenfactor, and Article Influence Scores. PLoS ONE, 5(4). DOI: 10.1371/journal.pone.0010204
One hundred years ago today, Richard Wetherill was shot and killed by Chischilly Begay near the western end of Chaco Canyon. That much is clear, but the circumstances surrounding Wetherill’s death are otherwise murky. The same could be said for his life and legacy. Wetherill was an enormously important figure to the history of archaeological [...]... Read more »
Snead, J. (1999) Science, Commerce, and Control: Patronage and the Development of Anthropological Archaeology in the Americas. American Anthropologist, 101(2), 256-271. DOI: 10.1525/aa.1918.104.22.1686
Why were the older people less affected by the new flu?
The elderly, especially those older than 65 years, that is, born before 1944, constitute the part of the population less affected by H1N1. It was suggested and later confirmed by CDC that it is about the prior immunity to the virus. These people probably have [...]... Read more »
Manicassamy, B., Medina, R., Hai, R., Tsibane, T., Stertz, S., Nistal-Villán, E., Palese, P., Basler, C., & García-Sastre, A. (2010) Protection of Mice against Lethal Challenge with 2009 H1N1 Influenza A Virus by 1918-Like and Classical Swine H1N1 Based Vaccines. PLoS Pathogens, 6(1). DOI: 10.1371/journal.ppat.1000745
The way we govern ourselves has changed fundamentally in the past 20 years, and we’ve barely noticed. The changes raise critical questions, which we have developed a habit of answering on a case-by-case basis, without considering the context and without … Continue reading →... Read more »
Leo, C. (2006) Deep Federalism: Respecting Community Difference in National Policy. Canadian Journal of Political Science/Revue canadienne de science politique, 39(03). DOI: 10.1017/S0008423906060240
What have people been talking about this week in high energy physics, astrophysics, gravitation, general relativity and quantum gravity?... Read more »
T. van Zoest, N. Gaaloul, Y. Singh, H. Ahlers, W. Herr, S. T. Seidel, W. Ertmer, E. Rasel, M. Eckart, E. Kajari, S. Arnold, G. Nandi, W. P. Schleich, R. Walser, A. Vogel, K. Sengstock, K. Bongs, W. Lewoczko-Adamczyk, M. Schiemangk, T. Schuldt, A. Peters, . (2010) Bose-Einstein Condensation in Microgravity. Science , 328(5985), 1540-1543. info:/10.1126/science.1189164
Bogdan A. Dobrescu, Patrick J. Fox, & Adam Martin. (2010) CP violation in B_s mixing from heavy Higgs exchange. arXiv. arXiv: 1005.4238v2
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