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  • December 12, 2010
  • 07:00 AM
  • 1,032 views

Preventing HIV Before Exposure

by Shaheen Lakhan in Brain Blogger

Currently, more than 33 million people worldwide are living with human immunodeficiency virus (HIV) infection. Each year, there are nearly 3 million new infections. The growing worldwide burden of this infection, which causes acquired immune deficiency syndrome (AIDS), has prompted researchers to investigate novel approaches to infection control and prevention. A recent investigation published by [...]... Read more »

Abdool Karim Q, Abdool Karim SS, Frohlich JA, Grobler AC, Baxter C, Mansoor LE, Kharsany AB, Sibeko S, Mlisana KP, Omar Z.... (2010) Effectiveness and safety of tenofovir gel, an antiretroviral microbicide, for the prevention of HIV infection in women. Science (New York, N.Y.), 329(5996), 1168-74. PMID: 20643915  

Golub SA, Kowalczyk W, Weinberger CL, & Parsons JT. (2010) Preexposure prophylaxis and predicted condom use among high-risk men who have sex with men. Journal of acquired immune deficiency syndromes (1999), 54(5), 548-55. PMID: 20512046  

Johnson WD, Diaz RM, Flanders WD, Goodman M, Hill AN, Holtgrave D, Malow R, & McClellan WM. (2008) Behavioral interventions to reduce risk for sexual transmission of HIV among men who have sex with men. Cochrane database of systematic reviews (Online). PMID: 18646068  

Oster AM Md, Dorell CG Md Mph, Mena LA Md Mph, Thomas PE Phd, Toledo CA Phd, & Heffelfinger JD Md Mph. (2010) HIV Risk Among Young African American Men Who Have Sex With Men: A Case-Control Study in Mississippi. American journal of public health. PMID: 21088266  

Supervie V, García-Lerma JG, Heneine W, & Blower S. (2010) HIV, transmitted drug resistance, and the paradox of preexposure prophylaxis. Proceedings of the National Academy of Sciences of the United States of America, 107(27), 12381-6. PMID: 20616092  

Grant, R., Lama, J., Anderson, P., McMahan, V., Liu, A., Vargas, L., Goicochea, P., Casapía, M., Guanira-Carranza, J., Ramirez-Cardich, M.... (2010) Preexposure Chemoprophylaxis for HIV Prevention in Men Who Have Sex with Men. New England Journal of Medicine, 2147483647. DOI: 10.1056/NEJMoa1011205  

  • December 12, 2010
  • 04:00 AM
  • 1,170 views

Ketogenic Diet for Alzheimer’s Disease?

by Steve Parker, M.D. in Diabetic Mediterranean Diet Blog

Ketogenic diets have seen a resurgence in the last two decades as a treatment for childhood epilepsy, particularly difficult-to-control cases not responding to drug therapy.  It works, even in adults.  That’s why some brain experts are wondering if ketogenic diets … Continue reading →... Read more »

Gasior M, Rogawski MA, & Hartman AL. (2006) Neuroprotective and disease-modifying effects of the ketogenic diet. Behavioural pharmacology, 17(5-6), 431-9. PMID: 16940764  

  • December 11, 2010
  • 05:30 PM
  • 673 views

The transcendant temporal lobe

by Tom Rees in Epiphenom

The temporal lobe of the brain - the bit just above where your ear is - keeps cropping up in studies of spirituality.

In this latest one, Peter Van Schuerbeek and colleagues from the University of Brussels have looked at the volume of grey matter in different parts of the brain in young women.

They were interested to see how the volumes of different parts of the brain correlate with personality, and in particular testing a particular model of personality called the Cloninger personality model.

This model has four temperament dimensions (harm avoidance, novelty seeking, reward dependence and persistence) and three character dimensions (self-directedness, cooperativeness and self-transcendence).

The "self-transcendence" component is related to the feeling that you are part of a broader universe in some deep way, and includes tendencies towards spiritualism.

They found that women with a high sense of self-transcendence had more grey matter in the right-hand side of the brain in the region of the middle temporal gyrus and the inferior parietal gyrus (the images on the left of the picture).

They had less grey matter in the left-hand side of the brain in the region of the inferior temporal gyrus and the sub gyral (in the parietal lobe). They also had less grey matter in the superior frontal gyrus.

All this is intriguing because other research has shown that damage to the right-hand temporal and parietal lobes can lead to increased spirituality. That may be because these regions are involved in spatial awareness.

Now, that doesn't match precisely with these findings in Belgian women (who have more grey matter in this region. But perhaps there is some similar mechanism at work!

Van Schuerbeek P, Baeken C, De Raedt R, De Mey J, & Luypaert R (2010). Individual differences in local gray and white matter volumes reflect differences in temperament and character: A voxel-based morphometry study in healthy young females. Brain research PMID: 21126511

This article by Tom Rees was first published on Epiphenom. It is licensed under Creative Commons.

... Read more »

  • December 11, 2010
  • 04:39 PM
  • 707 views

The Heightened Effects of Social Defeat on Dopamine Signaling

by Allison in Dormivigilia

Neuroscientists have found that social defeat is linked to heightened firing of dopamine neurons in the ventral tegmental area: a major constituent of the reward circuitry. Does this mean that you can become physiologically addicted to defeat???... Read more »

Jun-Li Cao,1,2 Herbert E. Covington III,3 Allyson K. Friedman,4 Matthew B. Wilkinson,3 Jessica J. Walsh,4, & Donald C. Cooper,1 Eric J. Nestler,3,4 and Ming-Hu Han1,3,4. (2010) Mesolimbic Dopamine Neurons in the Brain Reward Circuit Mediate Susceptibility to Social Defeat and Antidepressant Action. Journal of Neuroscience, 30(49), 16453-16458. info:/10.1523/JNEUROSCI.3177-10.2010

  • December 11, 2010
  • 03:21 PM
  • 1,283 views

Supramolecular chemistry

by egonw in Chem-bla-ics

Some smart software developer once said to not optimize your code too early. However, not caring about it at all does not help either. Some basic knowledge of memory management can keep you going. That is, I just ran into the limits of Oscar and ChemicalTagger. As I blogged earlier today, I am analyzing the BJOC literature, but Lezan and I are running into a reproducible out-of-memory exception. At first I thought it was a memory leak, as it was the 95th paper if fell over on, but after we optimized our code a bit, by reusing classes, the problem remained and turned out to be not in recreating objects (though the code is significantly faster now), but in a single BJOC paper being too large.

The particular paper is not even ridiculously large, though it has an amazing 800 references! The paper, Molecular recognition of organic ammonium ions in solution using synthetic receptors (doi:10.3762/bjoc.6.32), is in fact an interesting review paper on supramolecular chemistry. The molecules I worked on (see below) in my own supramolecular chemistry time (doing a M.Sc. minor (6 month practical) with Peter Buijnsters in organic chemistry in the group of Prof. Nolte), is actually a compound of the type they review, though surfactants are not really covered in it particularly.
Yeah, supramolecular chemistry has this nice level complexity; it is so supramolecular, that it is currently outside the scope of the molecular analysis of Oscar and ChemicalTagger ;)

Späth, A., & König, B. (2010). Molecular recognition of organic ammonium-ions in solution using synthetic receptors Beilstein Journal of Organic Chemistry, 6 DOI: 10.3762/bjoc.6.32

Buijnsters, P. J. J. A.; García-Rodríguez, C. L.; Willighagen, E. L.; Sommerdijk, N. A. J. M.; Kremer, A.; Camilleri, P.; Feiters, M. C.; Nolte, R. J. M.; Zwanenburg, B. (2002). Cationic Gemini Surfactants Based on Tartaric Acid: Synthesis, Aggregation, Monolayer Behaviour, and Interaction with DNA European Journal of Organic Chemistry, 2002 (8), 1397-1406 : DOI:10.1002/1099-0690(200204)2002:8%3C1397::AID-EJOC1397%3E3.0.CO;2-6... Read more »

Buijnsters, P. J. J. A.; García-Rodríguez, C. L.; Willighagen, E. L.; Sommerdijk, N. A. J. M.; Kremer, A.; Camilleri, P.; Feiters, M. C.; Nolte, R. J. M.; Zwanenburg, B. (2002) Cationic Gemini Surfactants Based on Tartaric Acid: Synthesis, Aggregation, Monolayer Behaviour, and Interaction with DNA. European Journal of Organic Chemistry, 2002(8), 1397-1406. info:/10.1002/1099-0690(200204)2002:83.0.CO;2-6

  • December 11, 2010
  • 01:16 PM
  • 4,772 views

Perspectives on Psychological Science: Blogs Don't Exist

by The Neurocritic in The Neurocritic

The Seductive Allure of Neuroscience ExplanationsThe previous post, Voodoo Correlations: Two Years Later, was a retrospective on the neuroimaging methods paper that was widely discussed in the blogosphere before it was considered "officially" published (Vul et al., 2009). The article, a controversial critique of the statistical analyses used by fMRI investigators in social neuroscience, made its initial appearance on Ed Vul's website once it was accepted by Perspectives in Psychological Sciences. This caused considerable consternation among the criticized authors and the journal editor (Ed Diener).Now, as part of the November 2010 issue of the journal (Diener's last as editor), six invited articles on Neuroimaging: Voodoo, New Phrenology, or Scientific Breakthrough? appear in a Special Section on fMRI (Diener, 2010). I was pleased to see that one of the articles addressed The Appeal of the Brain in the Popular Press (Beck, 2010), since this has been a major theme of my blog for almost five years. However, I was disappointed that the word "blog" was not mentioned at all in Beck's article.This should have come as no surprise, given the journal's response to bloggers in May 2009. The Editor's Introduction is worth a mention for the issues it raises about peer review and publication in these modern times.PREPUBLICATION DISSEMINATIONAs soon as I accepted the Vul et al. article, I heard from researchers about it. People around the globe saw the article on the Internet, and replies soon appeared as well. Although my plan was to publish the article with commentary, the appearance of the article on the Internet meant that researchers read the article without the accompanying commentaries and replies that I had planned to publish with it.In some fields such as economics, it is standard practice to widely disseminate articles before they are published, whereas in much of psychology this has been discouraged. An argument in favor of dissemination is that it speeds scientific communication in a fast-paced world where journal publication is often woefully slow. An argument against dissemination of articles before publication is that readers do not have the opportunity to simultaneously see commentary and replies. ... In the Internet age, the issue of prepublication distribution becomes all the more important because an article can reach thousands of readers in a few hours. Given the ability of the Internet to communicate so broadly and quickly, we need greater discussion of this issue.In reply, I wrote:Bloggers have discussed this specific issue months ago. For example, as noted in Mind Hacks,The paper was accepted by a peer-reviewed journal before it was released to the public. The idea that something actually has to appear in print before anyone is allowed to discuss it seems to be a little outdated (in fact, was this ever the case?).And The Neurocritic opined that...[The aggrieved authors] are not keeping up with the way that scientific discourse is evolving. Citing "in press" articles in the normal academic channels is a frequent event; why should bloggers, some of whom are read more widely than the authors' original papers, refrain from such a practice? Is it the "read more widely" part?-from The paper formerly known as "Voodoo Correlations in Social Neuroscience", by The NeurocriticDiener originally solicited six commentaries on the Vul et al. paper for the May 2009 issue of the journal. Ironically, authors on two of the papers have serious blogs:Statistical Modeling, Causal Inference, and Social Science is a blog written by Andrew Gelman, a Professor of Statistics and Political Science at Columbia. He was one of the first to blog about the paper in Suspiciously high correlations in brain imaging studies, with a more detailed post a month later (More on the so-called voodoo correlations in neuroscience). Lindquist and Gelman (2009) applauded the discussion engendered by "pre-publication dissemination":Their article has in a short time given rise to a spirited debate about key statistical issues at the heart of most functional neuroimaging studies. The debate provides a useful opportunity to discuss core statistical issues in neuroimaging and ultimately provides a chance for the field to grow and move forward. [citation needed] is the blog kept by Tal Yarkoni, a Post-Doc at the University of Colorado Boulder. He happens to be an expert in statistics for fMRI analysis, and another one of the authors invited to submit a paper for the Vul, Harris, Winkielman, and Pashler festschrift/verdammung (Yarkoni, 2009):In this article, I argue that Vul et al.'s primary conclusion is correct, but for different reasons than they suggest. I demonstrate that the primary cause of grossly inflated correlations in whole-brain fMRI analyses is not nonindependence, but the pernicious combination of small sample sizes and stringent alpha-correction levels. Far from defusing Vul et al.'s conclusions, the simulations presented suggest that the level of inflation may be even worse than Vul et al.'s empirical analysis would suggest. His blog started in October 2009, after the commentaries were published.The Appeal of the Brain in the Popular PressThat brings us back to the article by Diane Beck, an Assistant Professor in Psychology and Cognitive Neuroscience at the University of Illinois Urbana-Champaign. She examines the distorted media coverage of neuroimaging studies, and possible reasons for it (Beck, 2010):Since the advent of human neuroimaging, and of ... fMRI in particular, the popular press has shown an increasing interest in brain-related findings. In this article, I explore possible reasons behind this interest, including recent data suggesting that people find brain images and neuroscience language more convincing than results that make no reference to the brain (McCabe & Castel, 2008; Weisberg, Keil, Goodstein, Rawson, & Gray, 2008). I suggest that part of the allure of these data are the deceptively simply messages they afford, as well as general, but sometimes misguided, confidence in biological data. In addition to cataloging some misunderstandings by the press and public, I highlight the responsibilities of the research scientist in carefully conveying their work to the general public. While reading through the examples of poor media coverage, imagine the shock of recognition if you were to realize that you have written several trenchant blog posts criticizing these very articles. Yet all this work (and the writings of many others) is rendered invisible to the mainstream of the Association for Psychological Science.Why is blogging so non-existent in these circles? There's a large thriving community of science blogs. Go to ResearchBlogging.org and look under ... Read more »

Beck, D. (2010) The Appeal of the Brain in the Popular Press. Perspectives on Psychological Science, 5(6), 762-766. DOI: 10.1177/1745691610388779  

  • December 11, 2010
  • 11:57 AM
  • 1,332 views

The Newly Discovered Giant Flores Stork

by Greg Laden in Greg Laden's Blog

A new species of stork has been identified from Flores, which is the Indonesian island on which the famous "hobbit" fossils have been found. The "hobbit" is a form of hominid (human relative) that seems to be a diminutive form of Homo erectus but different enough from that widespread species to give it a distinct taxonomic status, Homo floresiensis. The Flores hominids were probably about 120 centimeters in height, and the new stork was probably about 180 centimeters in height. The following artist reconstruction is meant to demonstrate bigness of the stork in relation to our diminutive relative:




More on that artist's reconstruction later. Read the rest of this post... | Read the comments on this post...... Read more »

  • December 11, 2010
  • 11:11 AM
  • 1,254 views

Motor bias

by Janet Kwasniak in Thoughts on thoughts


Eagleman and Sejnowski report a series of experiments that go a long way to pinning down the nature of our conscious perception of movement. A number of illusions were used in experiments showing that they shared a common process: flash-lag (moving object aligned with flash is offset), flash-drag (flash is offset as result of nearby [...]... Read more »

  • December 11, 2010
  • 10:53 AM
  • 1,730 views

roger penrose’s cyclical cosmology revisited

by Greg Fish in weird things

A little while ago, we looked at the cyclical cosmology resurrected by Roger Penrose and his colleague Vahe Gurzadyan, and discussed the major problems it left unaddressed. Now, physicists have tried to replicate a cosmic map with wispy concentric circles of radiation and took to arXiv with their rebuttals. Yes, they could find the circles [...]... Read more »

V.G.Gurzadyan, & R.Penrose. (2010) More on the low variance circles in CMB sky. n/a. info:/1012.1486v1

Adam Moss, Douglas Scott, & James P. Zibin. (2010) No evidence for anomalously low variance circles on the sky. n/a. arXiv: 1012.1305v1

  • December 10, 2010
  • 09:24 PM
  • 657 views

Fatal Familial Insomnia and CJD – Dying to sleep

by Thomas Tu in Disease of the week!

In mid-1980 Italy, a 52 year old man complains of insomnia, waking easily when he does get sleep, and loss of libido. He knows it’s close to the end for him; he has seen this in his sisters. Within a … Continue reading →... Read more »

Lugaresi E, Medori R, Montagna P, Baruzzi A, Cortelli P, Lugaresi A, Tinuper P, Zucconi M, & Gambetti P. (1986) Fatal familial insomnia and dysautonomia with selective degeneration of thalamic nuclei. The New England journal of medicine, 315(16), 997-1003. PMID: 3762620  

  • December 10, 2010
  • 07:31 PM
  • 962 views

Ep 138: The health benefits of breakfast

by westius in Mr Science Show



A world first study conducted by Menzies Research Institute Tasmania has shown that skipping breakfast over a long period of time may increase your risk of heart disease and diabetes.

The study, Skipping breakfast: longitudinal associations with cardiometabolic risk factors in the Childhood Determinants of Adult Health Study, published in the American Journal of Clinical Nutrition, followed up a 1985 national sample of 9–15 year old Australian children. The original work looked at whether these children ate breakfast before school. In 2004–2006, the authors of the new research tracked down 2184 participants of the original study (26–36 years of age) and enquired into their breakfast eating habits. This style of study is called a Longitudinal Study.

After adjustment for age, sex, and sociodemographic and lifestyle factors, participants who skipped breakfast in both childhood and adulthood had a larger waist circumference, higher fasting insulin, and higher total cholesterol concentration than did those who ate breakfast at both time points. The researchers conclude that skipping breakfast over a long period may have detrimental effects on cardiometabolic health.

I had a great chat to lead researcher Kylie Smith about her study. Listen in to this show here (or press play below):



Songs in the podcast:

Harry Allen
"Breakfast At Tiffany's"

from "I Love Mancini" Amy Stephens Group
"Breakfast In Atlanta"

from "My Many Moods"

References:
Smith KJ, Gall SL, McNaughton SA, Blizzard L, Dwyer T, & Venn AJ (2010). Skipping breakfast: longitudinal associations with cardiometabolic risk factors in the Childhood Determinants of Adult Health Study. The American journal of clinical nutrition, 92 (6), 1316-25 PMID: 20926520
 

... Read more »

  • December 10, 2010
  • 05:46 PM
  • 2,126 views

Mucous Cancer - The mess of Pseudomyxoma peritonei

by James Byrne in Disease Prone


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This post is very important to me for two reasons. First of it’s my very first proper post at my new home here at Disease Prone. Secondly it is a post I have been in the process of putting together for a while after it was suggested to me by my lovely wife, a nurse whose insights in to disease and treatment I hope to include as regularly as possible. I hope you enjoy it and all future posts as much as I enjoy writing them. Peace out.
The last time I wrote about cancer it was for the Scientific American regarding how bacteria can be used as treatments so really it wasn’t even cancer I was talking about but when I was told about this doosey of a cancer I couldn’t help but write about it. This is significant for me as I am a bacteriologist who has spent a long time trying to avoid cancer (developing or writing about it), too many signalling pathways (imagine trying to memorise dozens of images like this), ick.

Pseudomyxoma peritonei is a relatively rare cancer that literally is translated to mean “false mucinous tumor of the peritoneum”. The tumour is unusual because it’s of a very specific cell type resulting in an overproduction and accumulation of mucous in the abdominal cavity, also known as the peritoneum.

I love using old Gray's Anatomy pictures. Click to embiggen but essentially the peritoneum is the blue bit.

Although controversial it is currently believed that these cancers start in the appendix and over time the small internal cavity fills with proliferating tumour cells and they mucous they are producing until the organ becomes occluded. Once occluded the appendix will fill up like a fleshy mucous balloon (‘distends’ in medical speak) and eventually will explode (again, ‘rupture’ for the medicos out there) leaking the appendix’s contents into the abdominal cavity. But the tumour isn’t dead so the production of mucous continues slowly leaking more and more mucous.
I say the origin is ‘controversial’ because it is very hard to work out for this type of cancer. Ordinarily when you are diagnosed with cancer the doctor finds the biggest tumour, points to the middle of it and says it started right here. With disseminated cancers like those in Pseudomyxoma peritonei there is no tumour (hence the false part of its name) and you only realise you have it when your insides start to fill up with mucous.
Treating these cancers, as you can imagine is quite difficult. First you have to detect it. As the tumour is slow growing, and doesn’t form a solid tumour it is very hard to detect pathology early enough to prevent rupturing of the appendix and release of muck into the abdominal cavity. However, early detection allows for the removal of the appendix and with a bit of luck all the cancerous tissue with it.
If you don’t find it early consider yourself booked in for cytoreductive surgery also known as debulking. This kind of surgery involves opening you up and removing as much mucous as possible from the peritoneal cavity and removing organs that have been exposed to the mucous + cancerous cell mix. Generally this means patients will have the organs at the bottom of the abdomen removed including ovaries, uterus, bladder, parts of the small intestine, appendix, and parts of the liver.
Then you hope and wish that works.

That dotted line across the middle is referring to the "transpyloric plane", essentially everything under it is removed in during cytoreductive surgery.
Alongside cytoreductive surgery you normally have your peritoneal cavity filled with good old chemotherapeutics.
Even if you survive all that it is very difficult to determine if the cancer is all gone for the same reasons it was hard to detect to begin with so patients look forward to a life of hospital waiting rooms as the current practice is to perform tests every 3 months to monitor for changes.
Commonly all of these techniques are now rolled into one operation called a Sugarbaker procedure. This procedure starts with complete cytoreductive tumour removal followed by surgical chemotherapeutic administration and removal of the right hemicolon, spleen, gallbladder, greater omentum and lesser omentum, uterus and ovaries in women and rectum in some cases then further work strips the peritoneum from the pelvis and diaphragm before removal of the tumour from the surface of the liver. Yeah, this operation takes about 10 hours and at the end you’re empty. That must be such a weird feeling.
Until my wife told me about this disease I had no idea such a cancer existed. Slow growing rare cancers rarely make it to public knowledge but they are really important. Pseudomyxoma peritonei does not kill many people per year as it is so rare but even after treatment the long term survival rates are only 40% or so, if you get it your in trouble.
Of all the cancers I’d like to never have (all of them) this one comes somewhere near the top of the list. As well as being deadly and impossible to treat with any confidence there’s a bunch of mucous and it’s the image of a burst appendix leaking dribbling mucous that I can’t shake.
Luckily, treatments are improving and survival rates are defiantly on the increase. One French study found th... Read more »

  • December 10, 2010
  • 05:18 PM
  • 455 views

When Your Powers Combine...

by Dan in The Endolymph

Atlantic bluefin tuna Thunnus thynnus are a highly migratory, pelagic, marine fish species.  Although I have never personally indulged myself by eating this fish, I have little doubt they are delicious.  How can I make such an assessment?  Well, Atlantic bluefin tuna are one of the most endangered animals on the planet and most assessments suggest they are on the brink of extinction.  The obvious solution to this problem would be to close down the Atlantic bluefin tuna fishery, but alas, as with most fisheries issues the solution is not so cut and dry.  The demand for bluefin tuna is incredibly high and in some countries, like Italy, the fishery represents a culturally important event.  Because of the importance and current status of Atlantic bluefin tuna, significant effort has been put forth to address questions regarding migrations and stock structure of the species.  Studying the movements of highly migratory species is a difficult task to say the least, but solutions to these difficulties are quite interesting.  A suite of methods including otolith microchemistry, genetics and electronic tagging has been used to decipher the life history of this species.  Block et al. (2005) suggested that using each of these methods individually would be insufficient, and combining these methods paints a more powerful, more complete picture of the life history of bluefin tuna in the Atlantic Ocean. Using otolith microchemistry, Rooker et al. (2003) identified unique chemical signatures in the otoliths of age-1 Atlantic bluefin tuna from the western and eastern Atlantic.  This information is important, because it can be used to classify adult bluefin tuna to natal origins and suggests that there are probably two separate spawning stocks.  This information is augmented by the findings of Carlsson et al. (2007) who used both nuclear loci and mtDNA to distinguish differences between Atlantic bluefin spawned in the Gulf of Mexico and the Mediterranean Sea.  Finally, electronic tagging by Block et al. (2005) revealed that bluefin tuna have trans Atlantic migrations and may show spawning site fidelity to the Gulf of Mexico and the Mediterranean Sea.  Of course there is significant room to expand on all of this research, but when the current information is combined, the life history of Atlantic bluefin tuna becomes clearer.  Using otolith microchemistry and genetic analysis to examine the origins of adult tuna should provide information on the mixing of individual stocks, which could answer questions like which side of the Atlantic is producing more fish?  This information would complement findings from electronic tagging studies quite nicely.  Whatever direction this research takes, it is pretty clear that one method will not provide all of the answers needed to make proper management decisions.  It is only in combining their powers that a clear life history and stock structure can be identified for this critically important species.Block BA, Teo SL, Walli A, Boustany A, Stokesbury MJ, Farwell CJ, Weng KC, Dewar H, & Williams TD (2005). Electronic tagging and population structure of Atlantic bluefin tuna. Nature, 434 (7037), 1121-7 PMID: 15858572Carlsson J, McDowell JR, Carlsson JE, & Graves JE (2007). Genetic identity of YOY bluefin tuna from the eastern and western Atlantic spawning areas. The Journal of heredity, 98 (1), 23-8 PMID: 17158466Rooker, J.R., D.H. Secor, V.S. Zdanowicz, G. De Metrio, & L. Orsi Relini (2003). Identification of Atlantic bluefin tuna (Thunnus thynnus) stocks from putative nurseries using otolith chemistry Fisheries Oceanography, 12 (2), 75-84... Read more »

Block BA, Teo SL, Walli A, Boustany A, Stokesbury MJ, Farwell CJ, Weng KC, Dewar H, & Williams TD. (2005) Electronic tagging and population structure of Atlantic bluefin tuna. Nature, 434(7037), 1121-7. PMID: 15858572  

Rooker, J.R., D.H. Secor, V.S. Zdanowicz, G. De Metrio, & L. Orsi Relini. (2003) Identification of Atlantic bluefin tuna (Thunnus thynnus) stocks from putative nurseries using otolith chemistry. Fisheries Oceanography, 12(2), 75-84. info:/

  • December 10, 2010
  • 05:18 PM
  • 1,540 views

Fetal Testosterone and Autistic Traits - Part II: Eye Contact

by Lindsay in Autist's Corner

Part of an ongoing series examining the empirical support for Simon Baron-Cohen's "extreme male brain" theory of autism... Read more »

Lutchmaya, S., Baron-Cohen, S., & Raggatt, P. (2002) Foetal testosterone and eye contact in 12-month-old human infants. Infant Behavior and Development, 25(3), 327-335. DOI: 10.1016/S0163-6383(02)00094-2  

  • December 10, 2010
  • 04:35 PM
  • 1,417 views

Microsatellite loci for Symbiodinium A3 Identified using next-generation sequencing

by epibio in EpiCentral

Microsatellites, or simple sequence repeats (SSRs), are molecular markers that can be readily investigated for population genetic studies. Microsatellites contain tandem repeats of 1-6 bases and are usually highly polymorphic, displaying a large number of alleles. The high degree of polymorphism makes microsatellites an ideal tool for studying gene-flow.

A recent study by Pinzon et al. developed ten polymorphic microsatellite loci for a common algae (Symbiodinium fitti, type A3) to study coral-algal symbioses. For this study, genomic DNA from three cultured strains of S. fitti were extracted and purified. Two different methods were employed to identify microsatellite loci with di-, tri-, and tetranucleotide motifs: i) Roche 454 sequencing; and ii) standard clone library (TA cloning) amplified and cycle sequenced using the ABI’s Big Dye Terminator Kit. For the Roche 454 sequencing, libraries were prepared from only 50 ng of double-stranded DNA using the Nextera™ DNA Sample Prep Kit (FLX Titanium-compatible), and sequenced on the 454 GS-FLX sequencer. The sequencing results helped the authors identify three to eight alleles for each haploid locus, with <95% of the samples possessing a single, symbiont, multilocus genotype (MLG).

The study demonstrates the utility of next-generation sequencing (NGS), especially with limited amounts of DNA. As shown in this study, NGS can be used to identify population genetic markers, which can help scientists better understand intraspecific and interspecific gene flow and population genetic structure.

Pinzón, J. et al. (2010). Microsatellite loci for Symbiodinium A3 (S. fitti) a common algal symbiont among Caribbean Acropora (stony corals) and Indo-Pacific giant clams (Tridacna) Conservation Genetics Resources, 3 (1), 45-47 DOI: 10.1007/s12686-010-9283-5... Read more »

  • December 10, 2010
  • 03:02 PM
  • 964 views

How to get rich fast with batteries

by Joerg Heber in All That Matters

The title of this blog post is a bit tongue in cheek, but the situation isn’t that far from the truth when it comes to rechargeable batteries such as lithium-ion batteries. Ever since lithium-ion batteries were first commercialized in 1991 by Sony, based on work by John Goodenough and others, they have been highly successful in the [...]... Read more »

Padhi, A., Nanjundaswamy, K.S., & Goodenough, J.B. (1997) Phospho-olivines as Positive-Electrode Materials for Rechargeable Lithium Batteries. Journal of The Electrochemical Society, 144(4), 1188. DOI: 10.1149/1.1837571  

Chan, C., Peng, H., Liu, G., McIlwrath, K., Zhang, X., Huggins, R., & Cui, Y. (2007) High-performance lithium battery anodes using silicon nanowires. Nature Nanotechnology, 3(1), 31-35. DOI: 10.1038/nnano.2007.411  

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  • December 10, 2010
  • 12:58 PM
  • 527 views

Speaking of Plowing

by teofilo in Gambler's House

The postulated connection between plow-based agriculture and a highly inegalitarian system of gender roles that I was talking about in the previous post reminded me of another paper about plowing and gender in a very different context.  This article, by Robin Ganev of the University of Regina, was published in the Journal of the History [...]... Read more »

  • December 10, 2010
  • 12:43 PM
  • 1,315 views

Hypertension Treatment with Renal Nerve Ablation

by William Yates, M.D. in Brain Posts

The neuroscience of hypertension covers several important domains.  Untreated hypertension can lead to central nervous complications such as stroke and vascular dementia.  Patients with essential hypertension show hyperactive renal sympathetic nerve outflow.  This produces several effects increasing blood pressure including: stimulation of renin, increased kidney sodium reabsorption and reduced blood flow to the kidney.  The kidney signals the brain areas controlling central sympathethic tone regulation.Diet, weight loss and pharmacotherapy form the basics for treatment of hypertension.  Despite a variety of drugs with different mechanisms of action many patients fail to achieve satisfactory blood pressure control.  Obviously, new strategies for blood pressure control are needed.One surgical strategy undergoing study is use of a endovascular cather to interrupt signals from the renal nerves to the kidney.  A recent study published in Lancet (The Sympliciity HTN-2summarized promising results from a randomized clinical trial using renal sympathetic denervation in a group of patients with treatment-resistant hypertension.  The key design elements of the study were:Subjects: 52 subjects randomized to surgical intervention, 54 controls not receiving the interventionEntry criteria: age 18-85 with systolic blood pressure of 160 mm Hg or greater despite compliance with three or more antihypertensive drugs (subjects could be enrolled if they had type 2 diabetes with a blood pressure of 150 mm Hg or more)Exclusion criteria: renal insufficiency, type 1 diabetes, contraindications to MRI, valvular heart disease, pregnancy, history of myocardial infarction, unstable angina or stroke in the last 6 monthsProcedure: A Symplicity catheter was inserted through the groin.  A series of low-power radiofrequency pulses was applied along both renal arteries with IV anxiolytics and narcotics used to control painThe primary endpoint defined for the study was systolic blood pressure change at 6 months.  The drop in blood pressures were pretty impressive in the intervention group compared to controls:6 month reduction in systolic 32 mm Hg intervention vs 1 mm Hg increase in controls6 month reduction in diastolic blood pressure 12 mm Hg intervention vs 0 mm Hg in controlsFive subjects in the intervention group had no decrease in systolic blood pressure and did not appear to benefit.  No significant complications were noted in the intervention group.  Renal function remained stable after the intervention.  The authors note that the durability of the intervention is unknown.  It is possible nerve regeneration over time may occur resulting in return of hypertension.  In early trials, the effect of the intervention has not be lost in follow up lasting 2 years. This intervention for hypertension appears very promising and deserves further study and long-term follow up.  If replicated it holds the potential to be a significant advance in treatment-resistant hypertension and the prevention on central hypertension complications of stroke and vascular dementia.Figure on main complications related to hypertension courtesy of Wikipedia Commons public domain file authored by Mikael Haggstrom. Symplicity HTN-2 Investigators, Esler MD, Krum H, Sobotka PA, Schlaich MP, Schmieder RE, & Böhm M (2010). Renal sympathetic denervation in patients with treatment-resistant hypertension (The Symplicity HTN-2 Trial): a randomised controlled trial. Lancet, 376 (9756), 1903-9 PMID: 21093036... Read more »

  • December 10, 2010
  • 12:01 PM
  • 694 views

Financial incentives and the brain's reward system

by NeuroKüz in NeuroKüz

Neuroeconomics is a big buzzword.Behavioural economics and the psychology of decision-making have rich histories, but with emerging brain imaging technology, we're now able to peer into some of the intricacies of neural processes as they occur while someone is making an important financial decision. The hope is that studies of brain activity will help guide economic theory and practice.In a study recently published in PNAS, Japanese researchers used functional MRI to examine brain responses to a phenomenon that challenges current economic theories, known as the "undermining effect." They found that people who were most susceptible to this effect also showed greatest changes in brain responses while playing a game that involved financial incentives.The undermining effect is a well-known psychological phenomenon in which a person is less likely to voluntarily engage in a task after performing that task for some sort of extrinsic reward, such as money or good grades. An example is a potential effect of schooling -- students who are forced to read Shakespeare because they are being graded on it are probably less likely to read Shakespeare for fun afterward than someone who didn't study Shakespeare in school. The researchers investigated the neural basis of the undermining effect by dividing study participants into two groups and scanning each person's brain twice. Both groups participated in a fun task, called the "stopwatch" task, wherein subjects viewed a stopwatch timer going from zero to five seconds, and they had to press a button within 50 milliseconds of the 5 second time point (if you don't believe this sounds fun, try it for yourself with a digital watch). One group received financial rewards (200 Japanese Yen or about $2.20) for doing this correctly, while the other group didn't receive performance-based rewards. The group receiving financial rewards showed greater activity in areas of the brain previously associated with award, the anterior striatum and midbrain, when subjects were winning money.Then participants got out of the brain scanner and waited in a quiet room, where they had free time to play the fun game or do anything else. As predicted by the undermining effect, those who were receiving financial rewards for their earlier performance on the fun game spent less time playing the fun game than those who weren't receiving awards. Then all subjects got back into the brain scanner, and they performed the fun task again, but crucially this time nobody received any financial rewards. More free time was given after the second scan, and once again the subjects who had earlier received money for their performance spent less time playing the fun game.The most interesting finding revealed by analysis of the brain activity was that individuals who played the fun game the least during free time also showed the greatest differences in reward-related brain activity between the two brain scans. In other words, those who felt most rewarded by financial incentives (as measured by brain activity) were the same individuals who were least likely to engage in the fun game when given free time. This suggests that the undermining effect is strongest in individuals who think of money as a reward.If the goal of neuroeconomics is to reveal information about behaviour that cannot be attained through psychological testing alone, this study appears to have succeeded. Importantly, it shows that each brain responds differently to incentives, and reward-related brain activity can predict the undermining effect within an individual. This is particularly interesting because it shows that not all individuals should be treated as equal in economic models of decision-making and incentive-driven behaviour.The findings also have implications for policymakers who often implement incentives in domains such as public health and schooling. As demonstrated by the undermining effect, removing extrinsic incentives to engage in an activity can have damaging effects on the desire to voluntarily engage in that activity.As to whether the study will succeed in impacting economic theory and practice -- that's for the economists to determine.Reference: Murayama K, Matsumoto M, Izuma K, & Matsumoto K (2010). From the Cover: Neural basis of the undermining effect of monetary reward on intrinsic motivation. Proceedings of the National Academy of Sciences of the United States of America, 107 (49), 20911-6 PMID: 21078974... Read more »

Murayama K, Matsumoto M, Izuma K, & Matsumoto K. (2010) From the Cover: Neural basis of the undermining effect of monetary reward on intrinsic motivation. Proceedings of the National Academy of Sciences of the United States of America, 107(49), 20911-6. PMID: 21078974  

  • December 10, 2010
  • 10:29 AM
  • 1,605 views

Boom: the destruction and rebirth of a marine ecosystem.

by Uncharted Atolls in Uncharted Atolls

In 1883, the world shuddered as the loudest known sound in human history echoed from its epicenter in Indonesia.  The noise generated by Krakatoa, a volcanic island in the Sunda Strait, was heard over 3,000 kilometers aways both to the … Continue reading →... Read more »

C. J. Starger, P. H. Barber, Ambariyanto, & A. C. Baker. (2010) The recovery of coral genetic diversity in the Sunda Strait following the 1883 eruption of Krakatau. Coral Reefs, 547-565. info:/10.1007/s00338-010-0609-2

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