October 4, 2009
04:44 PM
1,047 views

Carry a gun = you get shot more often

In a first-of its-kind study, epidemiologists at the University of Pennsylvania School of Medicine found that, on average, guns did not protect those who possessed them from being shot in an assault. The study estimated that people with a gun were 4.5 times more likely to be shot in an assault than those not possessing a gun.
source
Read the rest of this post... | Read the comments on this post...... Read more »

Branas, C., Richmond, T., Culhane, D., Ten Have, T., & Wiebe, D. (2009) Investigating the Link Between Gun Possession and Gun Assault. American Journal of Public Health. DOI: 10.2105/AJPH.2008.143099

Health

October 4, 2009
03:48 AM
1,317 views

Sex Determination in Sea Monsters

by Lucas in thoughtomics

Just to clarify this post’s title: I have not taken up an extremely dangerous but exciting new hobby. The sea monsters from the title have been extinct for a long time. But that doesn’t stop scientists from figuring out how sexual characteristics developed in these Jurassic reptiles.
In humans and in other mammals, the X and Y chromosomes are responsible [...]... Read more »

Organ, C., Janes, D., Meade, A., & Pagel, M. (2009) Genotypic sex determination enabled adaptive radiations of extinct marine reptiles. Nature, 461(7262), 389-392. DOI: 10.1038/nature08350

October 3, 2009
05:00 PM
688 views

It Hurts Less When I Can See It

by The Neurocritic in The Neurocritic

Fig. 1 (Longo et al., 2009). The mirror box technique in which the subject has the experience of viewing their right hand, while in fact seeing their left hand reflected in a mirror.Sight modifies somatosensation, by either enhancing or diminishing the subjective intensity of touch (Kennett et al., 2001) and pain (Ramachandran & Altschuler, 2009), respectively. These phenomena provide fascinating and lesser studied examples of crossmodal integration, or how signals from one sensory modality are combined with those of another to produce a unified percept. In an elegant series of experiments by Longo and colleagues, subjects who could see their own hand (either in a mirror or the real thing) reported less pain when exposed to the heat of a laser.Laser ‘Pain Beam’ under development by the U.S. military. NOT used in the "elegant" laser evoked potential experiments.Furthermore, an electrophysiological marker of pain was attenuated. This was measured from the EEG, time-locked to the application of the painful laser heat. These stimuli elicit a specific type of EEG response, called laser evoked potentials (LEPs). A sequence of three LEPs is generated in rapid succession, within the first 400 milliseconds after laser stimulation. These responses are called the N1, N2 and P2 potentials. As described in a review by Plaghki and Mouraux (2005),Laser heat stimulators selectively activate Aδ and C-nociceptors ["pain receptors"] in the superficial layers of the skin. Their high power output produces steep heating ramps, which improve synchronization of afferent volleys and therefore allow the recording of time-locked events, such as laser-evoked brain potentials. Study of the electrical brain activity evoked by Aδ- and C-nociceptor afferent volleys revealed the existence of an extensive, sequentially activated, cortical network. These electrophysiological responses are modulated by stimulus-driven and, even more extensively, top-down processes.These top-down processes include things like attention, expectation, and perhaps input from other sensory modalities. One advantage of LEPs is that you can determine exactly when in the pain processing stream these influences are active. Of greatest interest in this context is the N2-P2 complex, recorded at 195 milliseconds and 375 milliseconds after stimulation.Fig. 5 (Longo et al., 2009). Grand mean LEPs recorded from electrode Cz in the three experiments and N2/P2 peak-to-peak amplitudes at Cz (bottom right). Error bars are 1 SEM.The results demonstrated a cool new form of visually induced analgesia:Looking at one's hand produced significant reductions of subjective intensity and unpleasantness of laser pain and in the amplitude of the N2/P2 complex.... These effects were observed both when the illusion of looking directly at the hand was induced with a mirror box (Exps. 1 and 3) and when participants viewed their hand directly during stimulation (Exp. 2). The reduction was specific to seeing one's own hand (Exp. 3). What is the mechanism of action for these effects? First it's useful to know where in the brain the N2-P2 signals arise, because you can't tell from EEG alone. Plaghki and Mouraux review evidence from dipole models and invasive recordings, which haveconsistently revealed the activation of an extensive bilateral cortical network, comprising the secondary somatosensory cortex (S2), the insular cortex and the anterior cingulate cortex.It is noteworthy that the N1 response prior to the N2-P2 complex (not discussed here) is insensitive to the attentional and cognitive manipulations that affect the latter.But how does visual input influence pain processing in the insula and anterior cingulate? How does this crossmodal inhibition occur? This is tricky, because any coherent explanation would have to account for visual enhancement of touch perception. Longo and colleagues speculate that inhibitory GABA-containing neurons might be responsible:Could a common mechanism produce such divergent effects on touch and pain? One possibility would be a visually induced crossmodal activation of GABAergic interneurons. Injection of GABA antagonists increases the size of SI tactile receptive fields, suggesting that GABAergic interneurons function to sharpen tactile receptive fields, increasing tactile acuity. Conversely, GABA agonists are effective treatments for chronic central pain, suggesting that reduced GABAergic inhibition may be a major cause of chronic pain...Both the present results showing analgesic effects of seeing the body and previous findings showing tactile enhancement (Kennett et al., 2001) could therefore be explained by visual modulation of somatosensory GABAergic interneurons. This speculation is supported by multisensory influences on cortical inhibition in other physiological systems. For example, viewing a hand extends the TMS-evoked silent period compared with viewing a fixation cross.A related phenomenon was described by Mo Costandi in Distorting the body image affects perception of pain. Here, chronic pain patients viewed either magnified or "minified" versions of their affected arm while carrying out standarized motions. Subjective pain ratings were reported to be magnified or minified accordingly.Finally, looking at images other than of one's own body can affect the perception of pain as well. For instance, viewing aesthically pleasing art during the application of laser heat stimuli reduced pain ratings and LEP amplitudes (de Tommaso et al., 2008), as covered by The Neurocritic in Pain & Paintings: Beholding Beauty Reduces Pain Perception and Laser Evoked Potentials.In conclusion, Longo et al. note their results have possible implications for non-pharmacological treatments for pain:First, the present results show an analgesic effect of vision of the body for acute, rather than chronic, pain. Second, several authors have suggested that mirror therapy may operate by promoting plastic reorganization within somatosensory map or by correcting a distorted body image through visual recalibration of propriocepti... Read more »

Longo, M., Betti, V., Aglioti, S., & Haggard, P. (2009) Visually Induced Analgesia: Seeing the Body Reduces Pain. Journal of Neuroscience, 29(39), 12125-12130. DOI: 10.1523/JNEUROSCI.3072-09.2009

October 3, 2009
04:09 PM
688 views

Nutrient timing may make difference - for strength, body comp, muscle fiber...

by mc in begin to dig (b2d)

ResearchBlogging.orgCould changing when you have a recovery drink have a significant effect on strength, body comp and other performance factors? It may be that simple. If you like your workout routine, but want it to produce better results, you may find that changing one thing has a not insignificant effect. There seems to be significant benefit to strength, muscle fiber, body composition and muscle glycogen uptake based simply on when nutrients are taken around a workout. Likewise this nutrient timing requires no other change to one's diet to have this effect.... Read more »

CRIBB, P., & HAYES, A. (2006) Effects of Supplement Timing and Resistance Exercise on Skeletal Muscle Hypertrophy. Medicine , 38(11), 1918-1925. DOI: 10.1249/01.mss.0000233790.08788.3e

October 3, 2009
03:52 PM
1,475 views

Puffing up elliptical galaxies

by sarah in One Small Step

Elliptical galaxies are the boring uncles of the galaxy family: they’re amorphous blobby things, ubiquitous in the Universe, that contain a fairly uniform population of old, red stars. Without the interstellar gas and dust that is needed to harbour pretty sites of star formation, they are supremely unphotogenic. But they have far more going on [...]... Read more »

Damjanov, I., & et al. (2009) Red nuggets at z~1.5: Compact passive galaxies and the formation of the Kormendy relation. The Astrophysical Journal, 695(1), 101-115. DOI: 10.1088/0004-637X/695/1/101

Bezanson, R., van Dokkum, P., Tal, T., Marchesini, D., Kriek, M., Franx, M., & Coppi, P. (2009) The relation between compact, quiescent high-redshift galaxies and massive nearby elliptical galaxies: Evidence for hierarchical, inside-out growth. The Astrophysical Journal, 697(2), 1290-1298. DOI: 10.1088/0004-637X/697/2/1290

Fan, L., Lapi, A., De Zotti, G., & Danese, L. (2008) The Dramatic Size Evolution of Elliptical Galaxies and the Quasar Feedback. The Astrophysical Journal, 689(2). DOI: 10.1086/595784

Glazebrook, K. (2009) Galaxy formation: Too small to ignore. Nature, 460(7256), 694-695. DOI: 10.1038/460694a

Tomonori Totani. (2009) Size Evolution of Early-Type Galaxies and Massive Compact Objects as the Dark Matter. PASJ. arXiv: 0908.3295v1

October 3, 2009
02:23 PM
746 views

A Mathematical Model of p16INK4a and Aging

by Paul in Green Light Go

While the exact causes of mammalian aging are not know. The decline in replicative capacity of cells appears to be a factor. Activation of a particular gene p16INK4a causes the cell to arrest in a state of senescence at once suppressing cancer while attenuating its ability to replicate. Thus p16 may function via aging as [...]... Read more »

Denis Tsygankova, Yan Liub, Hanna K. Sanoffb, Norman E. Sharplessb, & Timothy C. Elstona. (2009) A quantitative model for age-dependent expression of the p16INK4a tumor suppressor. PNAS, 106(39). info:/

October 3, 2009
03:55 AM
1,134 views

Butterfly Phylogenetics

by Abhishek Tiwari in Fisheye Perspective

A recent study published in online issue of the Proceedings of the Royal Society B reconstructs a Nymphalid butterfly family tree and reveals family's evolutionary history which has remained a long term mystery due to the lack of butterfly fossils. The age of Nymphalidae butterflies has been the subject of longstanding confusion but according to this new study Nymphalids first evolved 90 million years ago which suprisingly coincides with the global rise of the angiosperms at about 100 million years ago.Based on sequences of 10 genes and 235 morphological characters for exemplars of 400 of the 540 valid Nymphalid genera representing all major lineages of the family authors have created a robust phylogenetic tree for the Nymphalidae butterfly family which represents the phylogenetic relationships of 400 genera of Nymphalidae based on a maximum likelihood analysis, along with outgroups. Clades representing subfamilies are coloured. (Image Copyright © The Royal Society 2009 )Interestingly the rate of diversification of the family tree or appearance of new Nymphalid species came to a slowdown around the 64 million years ago which coincides with the Cretaceous–Tertiary (KT) event leading to massive extinction of Nymphalid lineages and different species including non-avian dinosaurs. The ancestors of 10–12 lineages of the Neotropical and Oriental regions survived in KT event leading to subsequent elevated speciation rates in the Tertiary. Extinction, which according to many scientists was caused by a massive catastrophic bolide impact, have been further compounded as a result of widespread extinctions of angiosperm host plants in the same period, disrupting obligate butterfly–plant interactions.Reference:Wahlberg, N., Leneveu, J., Kodandaramaiah, U., Pena, C., Nylin, S., Freitas, A., & Brower, A. (2009). Nymphalid butterflies diversify following near demise at the cretaceous/tertiary boundary Proceedings of the Royal Society B: Biological Sciences DOI: 10.1098/rspb.2009.1303
Original article is
available at Fisheye Perspective blog. Stay
tuned for more posts and subscribe the RSS feed.

... Read more »

Wahlberg, N., Leneveu, J., Kodandaramaiah, U., Pena, C., Nylin, S., Freitas, A., & Brower, A. (2009) Nymphalid butterflies diversify following near demise at the cretaceous/tertiary boundary. Proceedings of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2009.1303

October 2, 2009
11:42 PM
866 views

Positive Psychology: Healing the well?

by Andrew Lyons in The Psych Student

I recently heard Martin Seligman talk here in London and then went back and watched his TED speech from last year. His work on Positive Psychology is has identified key identifiers that signify what we commonly call a full life, focused on optimism. But if it is possible, should we do away with depression?... Read more »

Seligman, M., Steen, T., Park, N., & Peterson, C. (2005) Positive Psychology Progress: Empirical Validation of Interventions. American Psychologist, 60(5), 410-421. DOI: 10.1037/0003-066X.60.5.410

October 2, 2009
09:24 PM
1,422 views

The feet of Ardipithecus ramidus

by zinjanthropus in A Primate of Modern Aspect

We’ve already covered Ardi’s hands here, so let’s move on to what is possibly the most interesting aspect of her skeleton: The feet.
As humans, we have pretty special feet. They’re good at dissipating all of the force that comes with walking on only two feet. They’re also good at propelling us forward, since [...]... Read more »

Lovejoy, C., Latimer, B., Suwa, G., Asfaw, B., & White, T. (2009) Combining Prehension and Propulsion: The Foot of Ardipithecus ramidus. Science, 326(5949), 72-72. DOI: 10.1126/science.1175832

October 2, 2009
07:36 PM
1,291 views

Climbing on the branches of the family tree: The hands of Ardipithecus ramidus

by zinjanthropus in A Primate of Modern Aspect

As everyone has already heard by now, the long-awaited Ardipithecus ramidus has finally been published, and boy is she a beauty! So many “anatomical surprises”! There are so many strange and new things about this skeleton that it took an entire issue of Science to describe them. Clearly then, it will take a few blog [...]... Read more »

Lovejoy, CO., Simpson, S., White, T., Asfaw, B., & Suwa, G. (2009) Careful Climbing in the Miocene: The Forelimbs of Ardipithecus ramidus and Humans Are Primitive. Science, 326(5949), 70-70. DOI: 10.1126/science.1175827

October 2, 2009
07:02 PM
1,538 views

Destigmatizing depression among medical (and graduate) trainees

by David J Kroll in Terra Sigillata

The Clinical and Translational Science Network (CTSciNet) section of Science Careers has just published a superb article by Karyn Hede on the issues of depression precipitated during the rigors of medical education. Hede is a freelance writer in Chapel Hill and has contributed before to Science Careers, particularly with this article on the challenges of women MD-PhDs and another on why so many of us have crappy interpersonal and lab management skills.

The current article focuses primarily on the medical profession given its placement in the clinical/translational section but these issues are true for PhD trainees as well:
Depression among medical trainees is well-documented. A recent large-scale survey of medical students and residents at six major medical schools revealed that one in five have mild to severe depression, a rate 15% to 30% higher than the general public. One out of every 17 even said they had thought about suicide. The study, reported in the journal Academic Medicine in February, brought to the fore the problem of depression among students immersed in the rigors of medical training.

"Certainly, medical school, residency, Ph.D. training, all those kinds of advanced degrees are set up with a lot of expectations, and by and large the people that are doing them are driven," says Deborah Goebert, a psychiatrist at the University of Hawaii, Manoa, and lead investigator of the study. These stressors, along with lack of sleep, financial concerns, and family pressures, can push people into an episode of clinical depression, she says. Read the rest of this post... | Read the comments on this post...... Read more »

Hede, K. (2009) Destigmatizing Depression. Science. DOI: 10.1126/science.caredit.a0900118

October 2, 2009
06:46 PM
837 views

Laugh. Then think.

by Emma in we are all in the gutter

This has turned out to be a busy day for posting on this blog! There’s one more thing that needs to be remarked on though – this years Ig Nobel prize winners were announced today by the Annals of Improbable Research. These awards, for those that don’t know, are counterparts to the official Nobel prizes; [...]... Read more »

Whitcome, K., Shapiro, L., & Lieberman, D. (2007) Fetal load and the evolution of lumbar lordosis in bipedal hominins. Nature, 450(7172), 1075-1078. DOI: 10.1038/nature06342

Javier Morales, Miguel Apátiga, & Victor M. Castaño. (2008) Growth of Diamond Films from Tequila. arXiv preprint. arXiv: 0806.1485v1

October 2, 2009
05:35 PM
743 views

Losing Crowd Control

by Journal Watch Online in Journal Watch Online

Population growth blamed for recent water shortages in southeastern US

... Read more »

Seager, R., Tzanova, A., & Nakamura, J. (2009) Drought in the Southeastern United States: Causes, Variability over the Last Millennium, and the Potential for Future Hydroclimate Change. Journal of Climate, 22(19), 5021. DOI: 10.1175/2009JCLI2683.1

October 2, 2009
03:40 PM
1,331 views

Discerning the role of the arcuate fasciculus in speech processing pt.1

by Wintz in A Replicated Typo

Originally identified by Reil (1809) and subsequently named by Burdach (1819), the arcuate fasciculus is a white-matter, neural pathway that intersects with both the lateral temporal cortex and frontal cortex via a “dorsal projection that arches around the Sylvain fissure.” (Rilling et al., 2008, pg. 426). Classical hypotheses saw this pathway as a critical component [...]... Read more »

CATANI, M., & MESULAM, M. (2008) The arcuate fasciculus and the disconnection theme in language and aphasia: History and current state. Cortex, 44(8), 953-961. DOI: 10.1016/j.cortex.2008.04.002

Glasser, M., & Rilling, J. (2008) DTI Tractography of the Human Brain's Language Pathways. Cerebral Cortex, 18(11), 2471-2482. DOI: 10.1093/cercor/bhn011

October 2, 2009
03:05 PM
1,584 views

How Brain Cells Avoid Getting All Tied Up

by Neuroskeptic in Neuroskeptic

During the development of the brain, young neurones need to form connections with other cells. But equally important, they need to avoid making connections with themselves.Unfortunately, the chance of this happening is rather high. As a neurone grows and branches out in all directions, many of the branches will inevitably come into contact with others from the same cell. They're right next to each other.So, how do brains achieve self-avoidance? The answer, according to a new Nature paper building on previous work, is a clever mechanism involving a single protein, Dscam1. The DNA code which produces it contains three sections (exons), which can each vary in several ways. There are 12 variants of exon 4, 48 of exon 6, and 33 of exon 9.That means that Dscam1 can end up in 12 x 48 x 33 = 19,008 different configurations (isoforms). It's as if whenever the protein is formed, it rolls a 12 sided dice, a 48 sided dice, and a 33 sided dice, and then ends up signalling the result. The diagram illustrates this nicely. The clever part is that each developing neurone expresses only a few isoforms, entirely at random.If a growing neuronal branch encounters another branch with the same Dscam1 isoform, the two identical proteins interact and the branches repel each other. Because every part of any given cell expresses the same "fingerprint", this produces self-avoidance. But the chance that another neighbouring cell will have the same protein is very small. There are billions of neurones in the brain, so many will share the same protein, but the chance of a cell encountering another nearby with the identical fingerprint is tiny.In this paper, the authors genetically engineered fruit flies (Drosophila) so that they had fewer than the normal 19,008 Dscam1 variants. (Previous work suggests that the system is similar in mammals.) Flies with 4,752 variants developed normally, but with only 1,152, problems arose: neurones got repelled from other nearby neurones because they shared the same protein. With 576, 24, or 12 isoforms, the problem became progressively worse, as the chance of two cells having the same isoform rose.So, in order to avoid tying themselves in knots, brains need somewhere between about one thousand and five thousand Dscam1 variants. It's an elegant solution to the problem of neurite self-avoidance, and a lovely example of evolution at work.Hattori D, Chen Y, Matthews BJ, Salwinski L, Sabatti C, Grueber WB, & Zipursky SL (2009). Robust discrimination between self and non-self neurites requires thousands of Dscam1 isoforms. Nature, 461 (7264), 644-8 PMID: 19794492... Read more »

Hattori D, Chen Y, Matthews BJ, Salwinski L, Sabatti C, Grueber WB, & Zipursky SL. (2009) Robust discrimination between self and non-self neurites requires thousands of Dscam1 isoforms. Nature, 461(7264), 644-8. PMID: 19794492

October 2, 2009
02:00 PM
1,380 views

The Ig Nobels are out! And the winners are....

by Christie Wilcox in Observations of a Nerd

If you haven't heard, the 2009 Ig Nobels have been given. The Ig Nobels are one of my favorite yearly treats. They are given to research that "first make people laugh, and then make them think."The prizes "celebrate the unusual, honor the imaginative - and spur people's interest in science, medicine, and technology."And the winners are...Veterinary medicine: Catherine Douglas and Peter Rowlinson of Newcastle University, UK, for showing that cows with names give more milk than cows that are nameless. Hear that, Bessie?Reference:Bertenshaw, C., & Rowlinson, P. (2009). Exploring Stock Managers' Perceptions of the Human–Animal Relationship on Dairy Farms and an Association with Milk Production Anthrozoos: A Multidisciplinary Journal of The Interactions of People & Animals, 22 (1), 59-69 DOI: 10.2752/175303708X390473Biology: Fumiaki Taguchi, Song Guofu and Zhang Guanglei of Kitasato University Graduate School of Medical Sciences in Sagamihara, Japan, for demonstrating that kitchen refuse can be reduced more than 90% in mass by using bacteria extracted from the feces of giant pandas.Reference: Taguchi, F. (2001). Microbial treatment of kitchen refuse with enzyme-producing thermophilic bacteria from Giant Panda feces. Journal of Bioscience and Bioengineering, 92 (6) DOI: 10.1016/S1389-1723(01)80326-1Medicine: Donald L Unger of Thousand Oaks, California, US, for investigating if knuckle-cracking causes arthritis of the fingers by diligently cracking the knuckles of his left hand but not his right hand every day for more than 60 years. Now that is dedication to a study! It doesn't, by the way.Reference: Donald L. Unger (1998). Does knuckle cracking lead to arthritis of the fingers? Arthritis & Rheumatism Arthritis & Rheumatism, 41 (5), 949-950Economics: The directors, executives, and auditors of four Icelandic banks have received the Ig Nobel in Economics for demonstrating that tiny banks can be rapidly transformed into huge banks, and vice versa - and for demonstrating that similar things can be done to an entire national economy. Physics: Katherine K Whitcome of the University of Cincinnati, Daniel E Lieberman of Harvard University and Liza J. Shapiro of the University of Texas were given the Ig Nobel in Physics for analytically determining why pregnant women do not tip over... most of the time.Reference:Whitcome, K., Shapiro, L., & Lieberman, D. (2007). Fetal load and the evolution of lumbar lordosis in bipedal hominins Nature, 450 (7172), 1075-1078 DOI: 10.1038/nature06342Chemistry: Javier Morales and his associates from the Universidad Nacional Autonoma in Mexico have received the Ig Nobel in Chemistry for creating diamond film from tequila. One diamond film, two diamond films, three diamond films... FLOOR!Reference: Javier Morales, Miguel Apátiga, & Victor M. Castaño (2008). Growth of Diamond Films from Tequila - arXiv: 0806.1485v1Literature: The Ig Nobel in Literature goes to Ireland's police service for writing and presenting more than 50 traffic tickets to the most frequent driving offender in the country - Prawo Jazdy - whose name in Polish means "Driving Licence". Public Health: Elena N Bodnar and her team from Chicago have won the Ig Nobel in Public Health for inventing a bra that can be quickly converted into a pair of gas masks - one for the wearer and one to be given to a needy bystander. Take that, bioterrorists!Reference: U.S. patent # 7255627, granted August 14, 2007 for a “Garment Device Convertible to One or More Facemasks.”Mathematics: Gideon Gono, governor of Zimbabwe's Reserve Bank, has received the Ig Nobel prize in Math for giving people a simple, everyday way to cope with a wide range of numbers by having his bank print notes with denominations ranging from one cent to one hundred trillion dollars. Now you'll never need change!Reference: Zimbabwe's Casino Economy — Extraordinary Measures for Extraordinary Challenges, Gideon Gono, ZPH Publishers, Harare, 2008, ISBN 978-079-743-679-4.And, last but not least:Peace: The Ig Nobel Peace Prize goes to Stephan Bolliger and his team from the University of Bern, Switzerland, for determining whether it is better to be smashed over the head with a full bottle of beer or with an empty bottle. In case you were wondering, both can fracture your skull. Reference: ... Read more »

Bertenshaw, C., & Rowlinson, P. (2009) Exploring Stock Managers' Perceptions of the Human–Animal Relationship on Dairy Farms and an Association with Milk Production. Anthrozoos: A Multidisciplinary Journal of The Interactions of People , 22(1), 59-69. DOI: 10.2752/175303708X390473

Taguchi, F. (2001) Microbial treatment of kitchen refuse with enzyme-producing thermophilic bacteria from Giant Panda feces. Journal of Bioscience and Bioengineering, 92(6), 602. DOI: 10.1016/S1389-1723(01)80326-1

Donald L. Unger,. (1998) Does knuckle cracking lead to arthritis of the fingers?. Arthritis , 41(5), 949-950. info:/

Whitcome, K., Shapiro, L., & Lieberman, D. (2007) Fetal load and the evolution of lumbar lordosis in bipedal hominins. Nature, 450(7172), 1075-1078. DOI: 10.1038/nature06342

Javier Morales, Miguel Apátiga, & Victor M. Castaño. (2008) Growth of Diamond Films from Tequila. -. arXiv: 0806.1485v1

Bolliger, S., Ross, S., Oesterhelweg, L., Thali, M., & Kneubuehl, B. (2009) Are full or empty beer bottles sturdier and does their fracture-threshold suffice to break the human skull?. Journal of Forensic and Legal Medicine, 16(3), 138-142. DOI: 10.1016/j.jflm.2008.07.013

Kent, R., Forman, J., & Bostrom, O. (2009) Is There Really a “Cushion Effect”?: A Biomechanical Investigation of Crash Injury Mechanisms in the Obese. Obesity. DOI: 10.1038/oby.2009.315

October 2, 2009
11:15 AM
1,994 views

Circadian and social cues regulate sodium channel trafficking in electric fish

by Mo in Neurophilosophy

SEVERAL hundred species of fish have evolved the ability to generate electric fields, which they use to navigate, communicate and home in on prey. But this ability comes at a cost - the electric field is generated continuously throughout life, so consumes a great deal of energy, and it can also attract predators which are sensitive to it. Electrogenic fish species therefore utilize various strategies to save energy and to minimize the likelihood of being detected. Some generate irregular pulses of electrical discharges whose rate can be modulated; others can also modulate the strength of the electric field.
A beautiful study published in the open access journal PLoS Biology now reveals the cellular and molecular mechanisms underlying one of these behavioural adaptations. It shows that in one species of electric fish, circadian cues and social encounters regulate the movements of proteins called voltage-gated sodium channels - which are crucial for generating the electric field - in cells of the electric organ. At night, low light levels and social interactions drive the insertion of sodium channels into the cell membranes, leading to a dramatic increase in the strength of the electric field.
Read the rest of this post... | Read the comments on this post...... Read more »

Markham, M., McAnelly, M., Stoddard, P., & Zakon, H. (2009) Circadian and Social Cues Regulate Ion Channel Trafficking. PLoS Biology, 7(9). DOI: 10.1371/journal.pbio.1000203

October 2, 2009
10:00 AM
955 views

Obesity and car crashes - does fat provide a protective cushion against injury?

by Travis Saunders, MSc in Obesity Panacea

While Travis and I often focus on the cardiometabolic and sometimes psychological complications of obesity, the consequences of carrying excess weight reach far beyond these two areas.

Take for example automobile collisions.

By and large, most cars on the road today are not built specifically to be driven by obese drivers. More importantly, the US Federal Motor Vehicle Safety regulations and New Car Assessment Program testing uses a crash test dummy with a BMI of ~25.5 kg/m2 to gauge how safe a given car, and what type of damage may be sustained by a passenger or driver of that car upon collision. Unfortunately, it is very likely that given the same type of vehicle and mode of collision, the mechanics of the trauma incurred by the driver and passenger will vary greatly when the BMI of these parties is 45 kg/m2 rather than 25.

Indeed, previous studies have found that increasing weight is associated with a greater mortality risk from a car crash, even when other factors such as seatbelt use, age, gender, seating position, and car weight are accounted for. Such a finding, however, does not allow us to deduce whether obese individuals are more injury prone given the same crash or simply if given the same injury sustained, obese people are more likely to die from complications.... Read more »

Kent, R., Forman, J., & Bostrom, O. (2009) Is There Really a “Cushion Effect”?: A Biomechanical Investigation of Crash Injury Mechanisms in the Obese. Obesity. DOI: 10.1038/oby.2009.315