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  • July 30, 2010
  • 12:32 AM
  • 804 views

Endocannabinoids and the runner's high

by NeuroKüz in NeuroKüz

Throughout most of human history, our hunter-gatherer ancestors had to engage in physical activity to obtain food. But nowadays we can drive to the supermarket, briefly walk through its aisles, check-out, then drive back home. This may seem like a luxury, but evolution hasn’t prepared us for such a drastic shift in behaviour.A possible explanation for the “runner’s high,” a feeling of intense euphoria associated with going on a long run, is that our brains are stuck thinking that lots of exercise should be accompanied by a reward. Perhaps our ancestors who were able to achieve the runner’s high while hunting for food ran more often than those who could not achieve the high. These ‘high-achievers’ (no pun intended) would gather more food as a result of their enhanced motivation, and would be more fit to pass on their genes to the next generation.Anecdotal reports of the runner’s high often come from endurance runners. However, there has been little scientific study of the runner’s high, so it is difficult to speculate about its role or mechanism. The traditional, widely-publicized explanation for the runner’s high is an “endorphin rush” that inhibits pain during vigorous exercise. However, other chemicals that potentially contribute to the high are epinephrine, serotonin, dopamine and endocannabinoids.In a study recently published in Experimental Neurology, investigators deleted the gene for the cannabinoid receptor CB1 in mice, and examined how this change to the endocannabinoid system affects voluntary running. The mice with CB1 deletions exhibited 30-40% less running activity than mice that did not get deletions. The knockout mice also had reduced hippocampal neurogenesis, or neuron birth that is known to be induced by exercise, but they were able to increase neurogenesis at a regular rate when they exercised.These findings indicate that the endocannabinoid system is somehow involved in the regulation of voluntary running activity. In particular, a reduction in CB1 levels could lead to less binding of endocannabinoids to receptors in brain circuits that drive motivation to exercise. It appears that the endocannabinoid system does not play a major role in controlling neurogenesis caused by exercise.It is easy to point to endocannabinoids as a candidate mediator of the runner’s high, since endocannabinoids are the body’s natural tetrahydrocannabinol (THC), the psychoactive ingredient of marijuana. The study described here doesn’t directly speak much to this proposed parallel, but if the motivation to exercise is considered to be related to the runner’s high, then endocannabinoids may be a driving factor to achieve the runner’s high.Physical activity has been associated with obtaining rewards throughout evolution. Today we might be left with a certain high associated with the prospect of obtaining a reward – a motivational high mediated by endocannabinoids. This ‘pre-runner’s high’ is an anticipation of the runner’s high, so the two experiences cannot necessarily be thought of as separate. That is – of course – assuming that the runner’s high happened often enough in history that our brains continue to develop to anticipate it. But even if the runner’s high was not common throughout our past, the peaceful feeling that almost everyone experiences after an exhausting run or bike ride should be adequate motivation to start moving.Endocannabinoids have previously been shown to increase in blood levels after exercise, so there is still a possibility that endocannabinoids mediate the runner’s high. It is most likely, however, that many chemicals converge on brain circuits that underlie the experience. Given the newly discovered role of endocannabinoids in motivation for exercise, it would be unsurprising if endocannabinoids played an important part in directly inducing the runner’s high. So kids out there: don’t smoke weed if you wish to activate your CB1 receptors. Run.References:Dubreucq S, Koehl M, Abrous DN, Marsicano G, & Chaouloff F (2010). CB1 receptor deficiency decreases wheel-running activity: consequences on emotional behaviours and hippocampal neurogenesis. Experimental neurology, 224 (1), 106-13 PMID: 20138171Fuss J, & Gass P (2010). Endocannabinoids and voluntary activity in mice: runner's high and long-term consequences in emotional behaviors. Experimental neurology, 224 (1), 103-5 PMID: 20353785... Read more »

  • July 29, 2010
  • 11:54 PM
  • 326 views

…Happiness, Fatness, and Pizza

by Rift in Psycasm

I’ve always wanted to create a meme. Something that I can just devise, and watch it spread like a virus. And I didn’t realize it until recently (though it was lurking in the back of my mind) that I’m fascinated by networks – how information is spread from person to person, and how each person [...]... Read more »

James H. Fowler, & Nicholas A. Christakis. (2009) Cooperative Behavior Cascades in Human Social Networks. PNAS Proceedings of the National Academy of Sciences of the United States of America. arXiv: 0908.3497v2

Christakis, N., & Fowler, J. (2007) The Spread of Obesity in a Large Social Network over 32 Years. New England Journal of Medicine, 357(4), 370-379. DOI: 10.1056/NEJMsa066082  

  • July 29, 2010
  • 09:36 PM
  • 1,553 views

Phytoplankton are disappearing, so we're all going to suffocate

by Bjørn Østman in Pleiotropy

Phytoplankton is responsible for about half of the total amount of oxygen produced by all plant life. That would make a 1% yearly reduction of phytoplankton a really negative outcome of global warming, don't you think?... Read more »

Boyce, D., Lewis, M., & Worm, B. (2010) Global phytoplankton decline over the past century. Nature, 466(7306), 591-596. DOI: 10.1038/nature09268  

  • July 29, 2010
  • 09:29 PM
  • 500 views

Neury Thursday: Neurobiological Mechanisms of "Pot Time"

by Allison in Dormivigilia

Using an array of neuroscience techniques, researchers have dissected the neurobiology of "pot time" by focusing on cannabinoid effects on circadian entrainment and neuronal activity of the SCN circadian clock.... Read more »

Claudio Acuna-Goycolea, Karl Obrietan, and Anthony N. van den Pol. (2010) Cannabinoids Excite Circadian Clock Neurons. Journal of Neuroscience, 30(30), 10061-10066. info:/10.1523/JNEUROSCI.5838-09.2010

  • July 29, 2010
  • 08:49 PM
  • 816 views

Force Fields and Plasma Shields

by Ryan Anderson in The Science of Starcraft

I was always a fan of the Protoss: super-advanced technology, powerful units, and those awesome plasma shields protecting everything from the lowliest probe to gigantic carriers. But I always wondered: could those force fields really work? Well… Sort of. It really depends on your definition of a force field and what you want to prevent [...]... Read more »

  • July 29, 2010
  • 07:47 PM
  • 1,039 views

Loops to tie a knot in proteins?

by Grant Jacobs in Code for life






Most proteins fold onto themselves without forming knots. A minority form a “topologically entangled conformation”, a knot.
Proteins are strings of amino acids, chained together one after the other.

The properties of proteins depends on their specific three-dimensional fold, how the chain of amino acids are arranged in space.
When proteins are first made by reading the RNA [...]... Read more »

  • July 29, 2010
  • 03:51 PM
  • 2,137 views

Hubble Bubble

by The Astronomist in The Astronomist.

The Copernican principle holds that humans are not privileged observers of the Universe. Copernicus stated that the Earth is not at the center of the solar system or at any particularly special position in the heavens. Modern cosmology has extended this idea to reason that the earth does not occupy any unique position in the Universe. Modern philosophy of science pushes the principle even further to conclude that every observer (even if they be they little green men) should reason as if they were the most standard observer. However, despite all these humble and rational thoughts it is still tempting to explain certain aspects of modern cosmology that seem finely tuned as consequences of observer selection effects. Namely I am speaking of dark energy or the accelerated cosmological expansion which supposedly could be explained if we occupy a privileged position near the center of a large, nonlinear, and nearly spherical void in mass density. The idea that the region of the cosmos around us could be a void is colloquially known in astronomy as the Hubble bubble. Technically a Hubble bubble is defined as a region of space wherein there is an observed departure of the local value of the Hubble constant from its cosmologically averaged value.Lets speculate a little further on what it would be like to live in a Hubble bubble. In the standard cosmological model of the Universe the structures we see today like galaxies and clusters of galaxies (and similarly the structures we don't see like the massive dark matter halos the visible matter is embedded in) formed from tiny primordial quantum fluctuations in the early universe. The fluctuations were random variations in density such that locations which were over-dense formed galaxies and those which were under-dense formed voids. It is possible, in fact statistically quite acceptable that there are voids of various sizes in the Universe. These voids would become increasingly under-dense as the Universe evolved and equivalently over-dense regions of the Universe became increasingly over-dense. Inside the void matter would expand outward due to the gravitational pull of matter in surrounding dense regions and thus an observer at the center of the void would see an accelerated expansion of matter outward. Now it is also possible that our entire observable Universe is a Hubble bubble, but that really flies in the face in all of cosmology. It is unfounded, absurd, and really the whole idea of a Hubble bubble may explain dark energy, but is hardly a very good explanation. The Hubble Bubble is wildly speculative and precision cosmology has almost completely defeated it as a credible explanation. First, as the framework of cosmology has been successful resting on the Copernican principle it seems odd to throw it out now. It is odd and largely misguided. First, the probability of producing a void of necessary magnitude; to mimic aspects of dark energy is extremely small in the standard structure formation models. Second, the probability of an observer being at the center (the only location where the expansion effect would be noticed) is extremely low. Finally, the void would need to be close to spherical to match the observed spatial smoothness (or isotropy) of the universe. These qualitative arguments and many more quantitative arguments from precision cosmology data are laid forth in a recent paper by A. Moss, J. Zibin, and D. Scoot titled Precision Cosmology Defeats Void Models for Acceleration. The abstract follows:The suggestion that we occupy a privileged position near the center of a large, nonlinear, and nearly spherical void has recently attracted much attention as an alternative to dark energy. Putting aside the philosophical problems with this scenario, we perform the most complete and up-to-date comparison with cosmological data. We use supernovae and the full cosmic microwave background spectrum as the basis of our analysis. We also include constraints from radial baryonic acoustic oscillations, the local Hubble rate, age, big bang nucleosynthesis, the Compton y-distortion, and for the first time include the local amplitude of matter fluctuations, σ8. These all paint a consistent picture in which voids are in severe tension with the data. In particular, void models predict a very low local Hubble rate, suffer from an "old age problem", and predict much less local structure than is observed. The paper makes several quantitative arguments against the plausibility any kind of void model for cosmic acceleration by drawing together an impressive amount of cosmological data and technical expertise, however, they don't ever mention the term Hubble Bubble. A 2007 paper by Conley et al. takes the Hubble Bubble paradigm head on: Is There Evidence for a Hubble Bubble? The Nature of Type Ia Supernova Colors and Dust in External Galaxies. In Conley et al. they explore how dust effects the colors of type Ia supernovae because they reason if the dust can be modeled as a purely local Milky Way effect then the supernovae data would actually favor the Hubble Bubble. Of course, despite difficulties the analysis, they find that in their parametrization there is evidence for more than the simply effect of local Milky Way dust implying doom for the Hubble Bubble. So the Hubble Bubble has been burst.References:Adam Moss, James P. Zibin, & Douglas Scott (2010). Precision Cosmology Defeats Void Models for Acceleration arXiv preprint arXiv: 1007.3725v1Conley, A., Carlberg, R., Guy, J., Howell, D., Jha, S., Riess, A., & Sullivan, M. (2007). Is There Evidence for a Hubble Bubble? The Nature of Type Ia Supernova Colors and Dust in External Galaxies The Astrophysical Journal, 664 (1) DOI: 10.1086/520625... Read more »

Adam Moss, James P. Zibin, & Douglas Scott. (2010) Precision Cosmology Defeats Void Models for Acceleration. arXiv preprint. arXiv: 1007.3725v1

  • July 29, 2010
  • 03:00 PM
  • 946 views

Making Sense of Sense

by Lorimer Moseley in BodyInMind

The roads less travelled – four paths to get from touch to the body I am studying medicine and as part of our course we do an Independent Learning project. I am doing mine in the Body in Mind research group here at NeuRA.  My first task is to review a key paper in the [...]... Read more »

Serino A, & Haggard P. (2010) Touch and the body. Neuroscience and biobehavioral reviews, 34(2), 224-36. PMID: 19376156  

  • July 29, 2010
  • 03:00 PM
  • 549 views

A note on the ADA, corporate sponsorship, and PepsiGate

by Colby Vorland in nutsci.org

Last week, the American Dietetic Association announced a new corporate sponsor: The Hershey Center for Health & Nutrition. The press release is vague but states that they:

“…will collaborate with ADA on consumer and health professional initiatives including an innovative, national consumer-focused nutrition education campaign.”

Whatever that means. But the goals of these partnerships are always primarily to improve brand image so more people will include their products in a “healthy” diet, or at least reduce negative perceptions of the brand. Hey, if the ADA allows them to sponsor, their products must be ok to eat, right? That is what I might think, or at least subconsciously perceive, if I didn’t study nutrition.
... Read more »

  • July 29, 2010
  • 02:47 PM
  • 212 views

Socializing Makes Thick-Skinned Fish

by Daniel Bassett in Chew the Fat

Cyprinid fishes (carps) show fright, or escape behaviour, when smelling alarm signals produced by conspecifics. These chemical alarm signals are found within special club cells and are released when these cells are ruptured. In nature, fish possessing the alarm club cells may become aware of a predator as it becomes labelled with the alarm pheromones when ingesting prey. In cyprinids it has been found that higher club cell densities exist in regions where there is a high abundance of predators. Higher club cell densities means the fish is able to produce a greater volume of alarm pheromones. Important when a predator could be lurking around any corner. The authors in this study hypothesized that club cell density is plastic in regards to predator presence.
For the study they raised crucian carp individually and in groups of four. For both rearing types, fish were exposed to the skin extracts of either conspecifics (alarm signals) or brown trout (without club cells), and provided food in either low or high food rations. Interestingly, they did not find an association with club cell density and the presence of an alarm pheromone or predator chemical cue. However, what they did find was that club cell density increased when fish were living in close quarters with conspecifics (ie group of four fish).
The data from this study suggests that group-raised fish are more chemically on guard than those raised singly. The data shows that club cell density can show a ten-fold increase through an increased feeding regime combined with group rearing. Club cell density is plastic and is likely to be controlled through internal physiological regulators such as blood androgen levels, but also through external regulators such as nutritional status and growth promoting factors via chemical sensing. But in the end it just makes sense to not spend growth energy on lots of alarm substances when there will be no one else around to heed your warning.
Stabell, O., & Vegusdal, A. (2010). Socializing makes thick-skinned individuals: on the density of epidermal alarm substance cells in cyprinid fish, the crucian carp (Carassius carassius) Journal of Comparative Physiology A DOI: 10.1007/s00359-010-0550-4... Read more »

  • July 29, 2010
  • 02:25 PM
  • 398 views

Placebo response without placebos

by Richard Morrisroe in DisgruntledPhD

Often, I hear that the placebo response is an artifact, merely a control for the "real" treatment. Today, I'd like to blog about a paper that suggests that every treatment is partially placebo. The paper is Benedetti et al 2003, and is probably one of the most interesting papers I have read.Essentially, the study looked at whether or not the awareness of treatment had any impact on the response to real drugs. To do this, they used (mostly) post-operative patients and looked at pain & anxiety.Each treatment was given in two conditions: open and hidden. In the open condition, patients were given a drug by a doctor who told them what they were getting. In the hidden condition, the drug was given without the knowledge of the patients.The study also looked at open and hidden interruptions in treatment, and the results were essentially the same (i.e. pain/anxiety levels were higher after the open interruptions).  The results were clear for pain and anxiety. Open infusions were much more effective than hidden ones, with pain decreasing much more in the open condition than in the hidden one.  The drug given for anxiety was diazepam (Valium) and this drug was COMPLETELY ineffective in reducing anxiety in the hidden condition. One could take these results to mean that Valium is a placebo, and only works because people believe it will. Is it the cultural lore thats developed around Valium be the only reason its effective? Shocking stuff, and food for thought the next time someone argues that placebos are "just" controls or have "no clinical significance".Now, its worth being aware of a few caveats to this study. Firstly, the open condition was actually measuring the difference between the presence of a doctor and the awareness of a treatment. This could be gotten around by using a prerecorded voice telling participants that they were about to get medication.  Unfortunately, no one appears to have done this study yet, but its an interesting question nonetheless. Benedetti, F., Maggi, G., Lopiano, L., Lanotte, M., Rainero, I., Vighetti, S., & Pollo, A. (2003). Open versus hidden medical treatments: The patient's knowledge about a therapy affects the therapy outcome. Prevention & Treatment, 6 (1) DOI: 10.1037/1522-3736.6.0001a... Read more »

  • July 29, 2010
  • 01:30 PM
  • 1,770 views

Socializing Makes Thick-Skinned Fish

by Daniel Bassett in Chew the Fat

Cyprinid fishes (carps) show fright, or escape behaviour, when smelling alarm signals produced by conspecifics. These chemical alarm signals are found within special club cells and are released when these cells are ruptured. In nature, fish possessing the alarm club cells may become aware of a predator as it becomes labelled with the alarm pheromones when ingesting prey. In cyprinids it has been found that higher club cell densities exist in regions where there is a high abundance of predators. Higher club cell densities means the fish is able to produce a greater volume of alarm pheromones. Important when a predator could be lurking around any corner. The authors in this study hypothesized that club cell density is plastic in regards to predator presence.... Read more »

  • July 29, 2010
  • 01:12 PM
  • 853 views

Global vs Local Cognitive Style in Autism: Central Coherence

by William Yates, M.D. in Brain Posts

The cognitive style known as central coherence is receiving increased attention across a variety of clinical neuroscience disorders.  I had not been familiar with this concept of central coherence.  Essentially, central coherence describes a style of thinking on a spectrum. On one end of the spectrum, you have individuals who tend to think globally or using a gestalt perspective.  The big picture is seen rather than paying attention to details.  The other end of spectrum includes individuals who are detail-oriented.  Their perspective bias is to focus on details.Being on either extreme of the spectrum can produces problems.  Very high central coherence can lead to problems with missing important details that need attention or action.  Those with very low or weak central coherence can be detail bound, losing sight of important global interpretations of the situation or environment. The imaging correlates of coherence are being explored.  Higher central coherence appears to involve increased right and left brain activation with problem-solving.  Weak central coherence has been accompanied by less bilateral activation with tasks.Children and adults  with autism spectrum appear to have weak central coherence and are overly focussed on details to the expense of a global perspective.  This could explain typical autistic behaviors such as valuing sameness, attending to parts of objects and persistence in behaviors related to details.Rhonda Booth and Francesa Happe from the Social, Genetic and Developmental Psychiatry Centre at the Institute of Psychiatry in London have published a study of central coherence in children with autism, ADHD and controls.There study involved a simple sentence completion task.  The example provided is--Complete this sentence "Hunting with a knife and".  Child with weak central coherence typically finish this sentence with "fork".  Normals tend to expand on a global response like "catch a bear". The authors tested a ten question Sentence Completion Task with the following findings:Completion scores (central coherence) increased with age--children younger than 13 had lower completion scoresMost (but not all) children with autism showed weak central coherence on the task (more local error responses)Children with ADHD did not differ from controls on the taskInhibition difficulties did not increase the weak coherence local response ratesThe authors conclude "the Sentence Completion Task appears to be a simple and easy-to-administer test capable of tapping local processing bias, or weak coherence, in a range of populations". You will likely be hearing more about the neuropsychological concept of coherence in a variety of studies across the clinical neuroscience disorders.Photo of Electrical Power Line Fire Courtesy of Yates PhotographyBooth, R., & Happé, F. (2010). “Hunting with a knife and … fork”: Examining central coherence in autism, attention deficit/hyperactivity disorder, and typical development with a linguistic task Journal of Experimental Child Psychology DOI: 10.1016/j.jecp.2010.06.003Lee PS, Foss-Feig J, Henderson JG, Kenworthy LE, Gilotty L, Gaillard WD, & Vaidya CJ (2007). Atypical neural substrates of Embedded Figures Task performance in children with Autism Spectrum Disorder. NeuroImage, 38 (1), 184-93 PMID: 17707658... Read more »

  • July 29, 2010
  • 12:52 PM
  • 716 views

ResearchBlogCast #11: Using the genome to identify species

by Dave Munger in ResearchBlogging.org News

How do you define a species? Most people would probably say species are similar organisms that can reproduce sexually to produce viable offspring. But what about organisms that don’t reproduce sexually? Surely they have species too.
Today we’re discussing new research suggesting a different way to define species, using their genomes. It’s an intriguing study that [...]... Read more »

  • July 29, 2010
  • 12:08 PM
  • 743 views

The Left Hand of Obama

by Neuroskeptic in Neuroskeptic

Voters in the 2008 Presidential election didn't have a meaningful choice. Whichever box they ticked, they were voting for a lefty.Yes, Obama and McCain are both sinistral, a rather unlikely occurrence since just 7-10% of adults are left handed. Netherlands-based neuroscientists Casasanto and Jasmin decided to make use of this coincidence to test the hypothesis that people tend to make "good" gestures with their dominant hand and "bad" ones with their off-hand, in a new PLoS paper: Good and Bad in the Hands of Politicians.They analyzed the final televised debates from the '04 and '08 elections, in which the candidates discussed various topics, both positive i.e. their own policies, and negative i.e. their opponent's Vietnam War records, choice of running-mate, and association with dodgy preachers. They also examined the gestures that the speakers made to accompany their positive or negative points, and recorded which hand they used. George W. Bush and John Kerry are both right-handed, by the way.Here's what they found:Both lefty candidates tended to use their left hands for good gestures and their right hands for bad ones, while the right-handed showed the opposite pattern. The data also reveal some interesting facts about the overall number of gestures: Obama had a hands-off approach with only 119 gestures in total, while McCain was gesticulating all over the shop (259). Bush and Kerry, however, were essentially equal (192 vs 193). Maybe Kerry's one extra gesture was just one too many for the electorate, thus costing him the Presidency.Anyway, does this prove that we use our dominant hands to make "good" gestures - supporting the notion that we unconsciously associate positive ideas with our dominant side of space, and negative ideas with our non-dominant side? Well, this study includes a large amount of data: it is, statistically, very likely that Obama really does tend to use his left hand over his right hand for positive gestures, i.e. this is unlikely to be due to random chance.But does this mean that there's a correlation between handedness and good-gesture-lateralization? We actually only have 4 data points relevant to that question: Obama, McCain, Kerry and Bush. We have a lot of information on each of those people, but there are only 4 independent sets of data.Suppose that everyone has a hand-they-use-for-good-gestures, and that it's 50/50 whether it's left or right - that is to say, suppose it has nothing to do with your general handedness. Clearly, there's then a 50% chance that any given person's good-gesture-hand will match their handedness, just by coincidence. There's a 1 in 4 chance that, for any two people, both will have a match; it's 1 in 8 for three people and 1 in 16 for four people. Which implies that there's a 1 in 16 chance that these results would have happened purely by chance.Maybe we need to look back to the Clinton / Dole debates to get some more data...Daniel Casasanto and Kyle Jasmin1 (2010). Good and Bad in the Hands of Politicians: Spontaneous Gestures during Positive and Negative Speech PLoS ONE... Read more »

Daniel Casasanto and Kyle Jasmin1. (2010) Good and Bad in the Hands of Politicians: Spontaneous Gestures during Positive and Negative Speech. PLoS ONE. info:/

  • July 29, 2010
  • 11:40 AM
  • 905 views

qPCR Analysis: It’s What’s Inside That Counts

by avi_wener in American Biotechnologist

If you watched the video on real time quantitative PCR data analysis, you should have a good understanding of real-time quantitative PCR basics and the associated data analysis techniques. Classical quantification techniques such as Livak, delta CT and the Pfaffl rely on linear regression analysis and are currently the most widely accepted methodologies for quantitative [...]... Read more »

  • July 29, 2010
  • 09:05 AM
  • 498 views

Global warming roundup: There's bad news, and weird news, but no really good news

by Jeremy Yoder in Denim and Tweed

Regardless of what James Inhofe thinks, global climate change is going to dramatically reshape the natural systems our civilization depends upon. Unfortunately, even as we embark on the radical experiment of turning our planet's temperature up to 11, we're just figuring out what results to expect. A whole series of papers released in the last week exemplify this point, showing that living communities' response to the changing planet may often be counter-intuitive.

.flickr-photo { }.flickr-frameright { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:40%;}.flickr-caption { font-size: 0.8em; margin-top: 0px; } Temperature stress may offset trees' ability to soak up carbon dioxide. Photo by Wade Franklin.Let's start with the bad news:

A study out in last week's PLoS ONE suggests that, rather than growing more rapidly and absorbing more carbon dioxide as the planet warms, forest trees may actually grow more slowly. More carbon dioxide in the atmosphere should generally increase plants' growth rates, since carbon dioxide is the raw material for photosynthesis. On the other hand, rising temperatures may put plants under so much stress that it offsets the benefits of more carbon dioxide.

Silva et al. examined core samples from four tree species—black spruce, red pine, red oak, and red maple—growing in Ontario forests, and found that the trees' growth rings were narrower in more recent years, as atmospheric carbon dioxide increased. Comparison of the growth rings to carbon isotope ratios (which capture a tree's response to temperature stress) suggested that the growth declines were due to less hospitable temperatures.

A large-scale historical study just out in Nature shows similar results for phytoplankton, microscopic photosynthetic organisms that form the base of ocean food chains. Working from historical records of ocean water transparency—phytoplankton makes water cloudy—going back to 1899, Boyce et al. found widespread declines in phytoplankton density [$a]. That's bad news on multiple levels, implying that phytoplankton growth isn't helping to absorb carbon dioxide, and that the oceans' productivity is declining with its foundational food sources, not just from overfishing. (See also coverage of this result by the BBC and NPR.)

.flickr-photo { }.flickr-frameright { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:40%;}.flickr-caption { font-size: 0.8em; margin-top: 0px; } Earlier springs mean bigger marmots. Photo by Blake Matheson.Now, the weird news:

The rule of thumb for plants' response to climate change has been that they'll respond to warmer temperatures by starting the growing season earlier. But a new survey of plant populations in Florida finds that as global warming progressed, most species flowered later. The authors suggest that this is because many Florida plant communities that are already adapted to warm conditions, and because climate change across much of Florida has meant not just warmer temperatures overall, but also greater seasonal variation in temperatures—areas where summer temperatures increased also tended to have decreasing winter temperatures. Faced with the possibility of more late frosts, Floridian plants are waiting till later in the spring to start flowering.

Another weird result of climate change received lots of press last week: a thirty-year study of yellow-bellied marmots in Colorado found that, as their alpine habitats grew warmer, the marmots grew bigger and more numerous [$a]. Warmer overall temperatures mean earlier spring thaws, so the marmots are emerging from hibernation earlier, have more time to grow and pack on fat reserves before hibernation in the fall, and can make more babies the next spring. Is this good or bad? Co-author Dan Blumstein's answer to that question in an interview with NPR is worth quoting:I don't know if I'm worried as much as I'm intrigued by it and I want to continue following the story. ... it's only through these long-term studies that we can gain important insights into what's happening, what's happened and ultimately identify mechanisms through which we may be able to predict what might happen in the future.Climate change is essentially a global gamble, with the function of ecological communities everywhere as the stakes. Even as we humans are unable to muster the will to stop it, we're finding out daily how many changes are on the way as the planet warms.

References

Boyce, D., Lewis, M., & Worm, B. (2010). Global phytoplankton decline over the past century. Nature, 466 (7306), 591-6 DOI: 10.1038/nature09268

Ozgul, A., Childs, D., Oli, M., Armitage, K., Blumstein, D., Olson, L., Tuljapurkar, S., & Coulson, T. (2010). Coupled dynamics of body mass and population growth in response to environmental change. Nature, 466 (7305), 482-5 DOI: 10.1038/nature09210

Silva, L., Anand, M., & Leithead, M. (2010). Recent widespread tree growth decline despite increasing atmospheric CO2. PLoS ONE, 5 (7) DOI: 10.1371/journal.pone.0011543

Von Holle, B., Wei, Y., & Nickerson, D. (2010). Climatic variab... Read more »

  • July 29, 2010
  • 08:00 AM
  • 1,396 views

Will Eating Blueberries Reduce Risk For Heart Disease?

by Arya M. Sharma in Dr. Sharma's Obesity Notes

Eating more fruit and vegetables is a common recommendation in dietary guidelines to prevent everything from obesity and heart disease to premature aging and cancer.
In this context, berries are of particular interest, as they are particularly rich in anti-oxidants and a variety of phytochemicals like polyphenols, anthocyanins, proanthocyanidins, resveratrol, flavonols, and tannins that have demonstrated [...]... Read more »

  • July 29, 2010
  • 07:56 AM
  • 522 views

Petro-cology

by Journal Watch Online in Journal Watch Online

If you thought the environmental problems associated with our dependence on oil were bad enough, just wait – the end of cheap oil could bring new and even more vexing ecological threats. That’s the message from three scholars making a provocative new call for ecologists to get more active in studying the implications of tightening […] Read More »... Read more »

  • July 29, 2010
  • 07:28 AM
  • 1,093 views

Dendreon's sipuleucel-T data from the IMPACT trial shows no surprises

by Sally Church in Pharma Strategy Blog

Yesterday was a travel day but thanks to gippy wifi and a packed day, I didn't have the opportunity to post about some interesting articles on prostate cancer published in the NEJM, which I read and digested on the train...... Read more »

Kantoff, P., Higano, C., Shore, N., Berger, E., Small, E., Penson, D., Redfern, C., Ferrari, A., Dreicer, R., Sims, R.... (2010) Sipuleucel-T Immunotherapy for Castration-Resistant Prostate Cancer. New England Journal of Medicine, 363(5), 411-422. DOI: 10.1056/NEJMoa1001294  

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