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  • July 12, 2011
  • 08:00 PM
  • 1,360 views

"They're doing WHAT?!" Revisiting ridiculed research

by NerdyOne in Try Nerdy

Fruit flies in France. Bear DNA in Montana. Catfish genome mapping in Alabama. The way some politicians tell it, taxpayers are footing the bill for a lot of really stupid research. But before you take their word for it, why not read on and do your own research so you can make that call for yourself?... Read more »

  • July 12, 2011
  • 05:11 PM
  • 1,713 views

Normal people more likely to recover from depression (probably)

by Tom Rees in Epiphenom

Patients who participate in medical trials are rarely asked about their religious beliefs, so we should be grateful for any studies that do. Here's one, and it's a study of citalopram (sold as Cilexa and Cipromil), which is a modern antidepressant - a bit like Prozac.

So they got religion info on 148 patients out of the 300-odd who took part in the trial (they were a slightly unusual bunch - 64% black, 64% women, and 79% single). And they asked them about their 'Religious well-being' (i.e. whether they thought that God loves them) and about how often they went to Church.

Then they checked up on how many patients had a remission of their depression after treatment. Unsurprisingly, there was no correlation at all between either measure of religiosity and their response (or lack of response).

But then they dug a bit further, splitting the group into three according to Church attendance (low, medium or high). Now they found something - people in the middle of the range had a better response than low or high frequency Church-goers.

What to make of this? Well, the authors speculate that frequent Church-goers might not take their medicine, or that highly depressed people might go to Church more often.

This doesn't explain the low response among infrequent churchgoers, however, and it's tempting to look for some kind of link to other research which shows that people at low and high levels of religiousness tend to be happier than those in the middle (see: the Happiness Smile).

But, to be honest, you do have to take these results with a pinch of salt. There are a number of problems with this study. First of, the cardinal rule of statistics is not to going digging around in the numbers if you don't find what you're looking for first time round. The reason is that the laws of chance means that you're bound to find some kind of pattern eventually - but it will probably be a mirage.

Indeed, a previous study found that religious well-being was linked to better response to antidepressants, in contradiction to this one. Just goes to show that you can't put too much store on these small, ad-hoc studies.

And lastly, there was no placebo control in this trial. That means we don't know if what we're seeing is a genuine effect of the medicine, or simply nature taking it's course.

Perhaps it's simply that people who do normal things, which in the USA (especially the Black community) means things like going to Church regularly but not obsessively, are more likely to recover from depression!



Schettino, J., Olmos, N., Myers, H., Joseph, N., Poland, R., & Lesser, I. (2011). Religiosity and treatment response to antidepressant medication: a prospective multi-site clinical trial Mental Health, Religion & Culture, 1-14 DOI: 10.1080/13674676.2010.527931

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



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  • July 12, 2011
  • 05:07 PM
  • 2,491 views

Cadence and injuries: Once more, with science

by Dave Munger in Science-Based Running

The plan for this site has always been to supplement discussion of peer-reviewed science with other reasoned discussions based on anecdotes and experience. When I’m discussing the peer-reviewed research, I always include the Research Blogging icon you see at the top of this post. When I’m discussing books or other non-peer-reviewed sources, I don’t. That [...]... Read more »

  • July 12, 2011
  • 04:12 PM
  • 1,083 views

Face off

by Africa Gomez in BugBlog

Ectemnius wasps are skilled fly hunters. Not only they hunt flies, but some species specialise in hoverflies, those masters of controlled flight. Like their prey, Ectemnius wasps are able to hover. As their large eyes suggest, they hunt visually and inspect flower patches that hoverflies frequent, hovering a bit, changing body direction, inspecting their terrain thoroughly. Once they detect a hoverfly, they try to approach from behind, and when at about 10 cm they aim and attack. Ectemnius provisions its nest - dug in dead wood - with hoverflies, which will serve as food for its larvae. The adults themselves feed on nectar. I was trying to photograph this digger wasp stalking hover flies, when it came across a male Syritta pipiens. The tiny hoverfly male, which often confronts other hoverfly males on this patch of wild rocket, instead of fleeing, it confronted the wasp, mirroring the predator movements and keeping his distance, both insects hovering perfectly still in front of each other for a few moments. Surprisingly, the wasp did not attack the fly and just moved on. Some insects have been shown to display a stealth strategy called "motion camouflage" by which an individual (the shadower) can conceal its movements to another individual (the shadowee) by maintaning its position in the retina of the shadowee. The shadower then appears as an stationary object from the point of vision of the shadowee. Some male hoverflies (and Syritta pipiens in particular) use this flying strategy to track females undetected and dragonflies use it to avoid being detected when intruding in other territories and it is also suspected to be used by visual insects when approaching prey. A range of models have been developed to simulate this strategy. Unsurprisingly, engineers are developing motion camouflage strategies to be applied to robots, satellites or with military purposes. According to Justh & Krishnaprasad:Motion camouflage can be used by a predator to stealthily pursue the prey, but a motion-camouflage strategy can also be used by the prey to evade a predator. The only difference between the strategy of the predator and the strategy of the evader is that the predator seeks to approach the prey while maintaining motion camouflage, whereas the evader seeks to move away from the predator while maintaining motion camouflage.I wonder if this was the case in the above photo. A temporary stale mate, but the prey got away.ReferencesJusth, E., & Krishnaprasad, P. (2006). Steering laws for motion camouflage Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 462 (2076), 3629-3643 DOI: 10.1098/rspa.2006.1742Mizutani, A., Chahl, J., & Srinivasan, M. (2003). Insect behaviour: Motion camouflage in dragonflies. Nature, 423 (6940), 604-604 DOI: 10.1038/423604a... Read more »

Justh, E., & Krishnaprasad, P. (2006) Steering laws for motion camouflage. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 462(2076), 3629-3643. DOI: 10.1098/rspa.2006.1742  

Mizutani, A., Chahl, J., & Srinivasan, M. (2003) Insect behaviour: Motion camouflage in dragonflies. Nature, 423(6940), 604-604. DOI: 10.1038/423604a  

  • July 12, 2011
  • 04:00 PM
  • 2,024 views

Rats, Bees, and Brains: The Death of the “Cognitive Map”

by Jason Goldman in The Thoughtful Animal

Humans, just like all other animals, face the same problem every day: how do we get around the world? I don’t mean how do we walk, swim, crawl, or fly. I mean, how do we navigate? If I leave in search of food, how do I find my way back home? ... Read more »

Tolman, E. (1948) Cognitive maps in rats and men. Psychological Review, 55(4), 189-208. DOI: 10.1037/h0061626  

O'Keefe J, & Speakman A. (1987) Single unit activity in the rat hippocampus during a spatial memory task. Experimental brain research. Experimentelle Hirnforschung. Experimentation cerebrale, 68(1), 1-27. PMID: 3691688  

Simons, D., & Wang, R. (1998) Perceiving Real-World Viewpoint Changes. Psychological Science, 9(4), 315-320. DOI: 10.1111/1467-9280.00062  

  • July 12, 2011
  • 12:42 PM
  • 1,681 views

Drive a lot? Housing density may not be to blame

by Tim De Chant in Per Square Mile

Pushing high density living may seem like a good way to get people out of their cars—saving them money, curbing emissions, and reducing oil dependence—but densification may not be a silver bullet, according to one recent study. The authors dug into the National Household Transportation Survey to examine per household vehicle ownership rates, vehicle miles [...]... Read more »

  • July 12, 2011
  • 12:34 PM
  • 2,000 views

It's Magnetic Moment Season: Measuring Various g-Factors

by Chad Orzel in Uncertain Principles

Among the articles highlighted in this week's Physics is one about a new test of QED through a measurement of the g-factor of the electron in silicon ions. This comes on the heels of a measurement of proton spin flips (this includes a free PDF) a couple of weeks ago, and those, in turn, build on measurements of electrons from a few years back, which Jerry Gabrielse talked about at DAMOP. Evidently, it's magnetic moment season in the world of physics.

The media reports on the proton experiment tend to be a little garbled in a way that reveals the writers don't quite understand what's going on. So let's take a crack at explaining this in ResearchBlogging form, in the usual Q&A format.

So, what's the deal with all this stuff? These look like very different experiments, and I don't see how they're related. Well, they're all using different systems, but in the end, they're after the same thing: measurements of what's known as the "g-factor" for some particle or another. This is a dimensionless number that relates the spin of a particle to its magnetic moment.

OK, what? Well, fundamental particles like electrons have a property known as "spin," which is an intrinsic angular momentum, as if the particles were spinning. They're not literally spinning balls of charge, and the behavior is somewhat strange compared to ordinary spinning objects (as explained with SteelyKid's help last summer), but in many ways they behave as if they were little spinning charges.

One of the things that spinning charges do is they produce a small magnetic field. For a literal spinning ball of charge, you can understand this by thinking of the charge on the surface as a little loop of current, which produces a magnetic field characterized by the "magnetic moment." If electrons are going to have the properties of a spinning thing, then, they need to produce a small magnetic field of their own.

If the electron was really a spinning charged ball, then the conversion from the rate of spin to the size of its magnetic moment would be really simple. Since the electron isn't really a spinning ball, though, there's a numerical factor that enters into the calculation. This is generally given the symbol "g," and thus is known as the "g-factor" for the electron.

And this thing has been measured? And calculated theoretically. The best current measurement of the electron g-factor was made by the Gabrielse group at Harvard, and gives a value of:

g/2 = 1.001 159 652 180 73 (28)

This agrees perfectly with a theoretical calculation of the expected value using quantum electro-dynamics (QED), which is why I tend to say that QED is the most precisely tested theory in the history of science.

How do they measure all those digits? It's a really impressive trick, involving holding a single electron in a "Penning trap," which confines it with the help of a strong magnetic field.
Read the rest of this post... | Read the comments on this post...... Read more »

Sturm, S., Wagner, A., Schabinger, B., Zatorski, J., Harman, Z., Quint, W., Werth, G., Keitel, C., & Blaum, K. (2011) g Factor of Hydrogenlike ^{28}Si^{13 }. Physical Review Letters, 107(2). DOI: 10.1103/PhysRevLett.107.023002  

Ulmer, S., Rodegheri, C., Blaum, K., Kracke, H., Mooser, A., Quint, W., & Walz, J. (2011) Observation of Spin Flips with a Single Trapped Proton. Physical Review Letters, 106(25). DOI: 10.1103/PhysRevLett.106.253001  

  • July 12, 2011
  • 11:57 AM
  • 1,680 views

“Eye of newt” reverses a long-held scientific dogma

by Sanford- Burnham in Beaker

Contrary to long-held belief, at least one animal (the newt) can continue to regenerate tissue even in old age—a finding that might help scientists understand why humans can’t, and allow them to do something about it.... Read more »

Eguchi, G., Eguchi, Y., Nakamura, K., Yadav, M., Millán, J., & Tsonis, P. (2011) Regenerative capacity in newts is not altered by repeated regeneration and ageing. Nature Communications, 384. DOI: 10.1038/ncomms1389  

  • July 12, 2011
  • 11:52 AM
  • 2,324 views

Is Bo Obama a Fraud?

by Elizabeth Preston in Inkfish

A hypoallergenic dog, we're told, is one that politely keeps its dander to itself and makes the air safer for allergy sufferers to breathe. Yet a new study claims to have debunked the whole notion of the allergy-friendly dog. Is this fair?Researchers from the Henry Ford Health System in Detroit studied a group of 173 homes that had both a baby and exactly one dog. After surveying each dog's owners about its breed, size, and how much time the dog spent indoors, the researchers collected a sample of dust from the floor of the baby's bedroom. They then measured the amount of dog allergen in each sample (the main allergy-causing ingredient in dog dander is a molecule called Can f 1).The families' dogs came from 60 different breeds. Researchers divided these dogs into hypoallergenic and non-hypoallergenic groups and looked for a difference in the amount of allergen the dogs left on their floors. Since "hypoallergenic" is not a label that's been defined scientifically--the problem that drove this study in the first place--the researchers tried several different methods to group the dogs. In their looser groupings, they put any dog that turned up in an internet search for allergy-free animals into the hypoallergenic category. They tried including, or not including, mutts with one supposedly hypoallergenic parent. In the strictest grouping, they considered only purebreds defined by the American Kennel Club as hypoallergenic, and compared them to all other dogs.No matter how they sliced it, though, the researchers couldn't come up with a significant difference in the allergen level between the homes of hypoallergenic and non-hypoallergenic dogs. Furthermore, only 10 homes had no detectable amounts of allergen in their dust samples, and none of these homes held hypoallergenic dogs. "We found no scientific basis to the claim hypoallergenic dogs have less allergen," author Christine Cole Johnson said in a press release. (The paper will be published online here.)So have we all been lied to? Is this dog, famously invited into the First Family because it wouldn't trouble little Malia's allergies, part of a large-scale deception?The headlines would have you believe so: There's No Such Thing as Hypoallergenic Dogs, they say. Hypoallergenic Dogs Are Just a Myth. Don't Waste Your Money.The authors of the study say it's unclear how the idea of the hypoallergenic dog originated, though it was in the late 20th century that the concept became popular. In a previous study, researchers shaved hair off of dogs of several breeds and measured the allergen present. Those authors found that although there was significant variation between breeds, there was also plenty of variation between individual dogs. And they found that poodles, dogs commonly called hypoallergenic, had a high level of allergen on their fur compared to other breeds. Christine Johnson and her co-authors wanted a more meaningful measurement of how much allergen was in the atmosphere of dog-owning homes, so they collected dust from the floors rather than fur from the dogs themselves.However, neither study measured the amount of allergen in the air, where it's actually inhaled by allergy sufferers. Allergen that's settled on the floor might be a good approximation of what was previously in the air--except that Can f 1, the allergen being measured, has two major sources: the fur and the saliva. Dogs that are heavy droolers, or ardent crumb seekers, could be depositing allergens all over the floor without necessarily impacting how much is in the air."Hypo-" means "less," not "none." The American Kennel Club says that dogs producing less dander "generally do well with people with allergies," and recommends 11 breeds to try. But this study didn't have a large enough sample size to look at individual breeds; it could only compare groups of dogs. So while the study didn't find an obvious difference between supposedly hypoallergenic dogs--as a group--and other dogs, the study did not show that there's no such thing as a hypoallergenic dog.If you're looking for a dog that doesn't trigger your allergies, you'd be better off spending some time around the dog itself than relying on an internet categorization. The variation between individual dogs' dander production might be more important than their breeds, anyway. Whether or not some breeds are truly hypoallergenic, science owes it to the allergy-ridden to create useful tests and meaningful labels for dogs. No one should have to live in fear of Bo.Bo: Official White House photo by Chuck Kennedy.Charlotte E. Nicholas, M.P.H., Ganesa R. Wegienka, Ph.D., Suzanne L. Havstad, M.A., Edward M. Zoratti, M.D., Dennis R. Ownby, M.D., & Christine Cole Johson, Ph.D. (2011). Dog allergen levels in homes with hypoallergenic compared with nonhypoallergenic dogs American Journal of Rhinology & Allergy... Read more »

Charlotte E. Nicholas, M.P.H., Ganesa R. Wegienka, Ph.D., Suzanne L. Havstad, M.A., Edward M. Zoratti, M.D., Dennis R. Ownby, M.D., & Christine Cole Johson, Ph.D. (2011) Dog allergen levels in homes with hypoallergenic compared with nonhypoallergenic dogs. American Journal of Rhinology . info:/

  • July 12, 2011
  • 10:41 AM
  • 1,709 views

Some musings on sustainability and obesity: focusing on BOTH physical activity & diet needed

by Megan Carter in Verdant Nation

There is no disputing that diet and physical inactivity are contributors to the obesity epidemic. A recent debate involving Drs Yoni Freedhoff and Bob Ross showed that both are important (I don’t think there was consensus in the audience as to who won). What I want to highlight in this post is that, from a sustainability perspective (see my previous post for a definition), it is a moot point to argue over the relative importance of each.Our food system has changed dramatically over the last few decades. We can get tasty, energy dense, often nutrient-poor foods anywhere, for very little money. And we’re constantly bombarded with advertisements to buy and eat these foods. What’s more is that we have almost completely engineered physical activity out of our daily life. For instance, most jobs nowadays require sitting for 8 hours (I am sitting as I write this), escalators and elevators do the climbing for us and are easily accessible, and we live far from where we work, play, or go to school so often must rely on the car, which involves more sitting.I think there is a consensus developing among obesity researchers and health professionals that obesity (or diabetes or other related diseases) is not entirely the fault of the individual. In my opinion, unhealthy behaviours are a natural response to our “obesogenic” environment, which increase a person’s risk of developing obesity. So then why do we expect that prevention or treatment efforts targeted at the individual will be effective and maintained over the long-term? To fix our deranged food system and culture of sitting requires interventions at higher levels of social organization, including changes stemming from the local community, municipal, provincial, and national governments, as well as the global community.In the last 10 years there has been a boom the number of scientific studies examining how our environments, beyond the household, are associated with obesity. The majority of these studies have been observational, with a cross-sectional design, and have looked at things like how street infrastructure, fast food restaurant density, and socioeconomic-level of residential neighbourhoods relate to obesity among adults.  Children have been less studied in this regard, as well as other types of environmental exposures, such as social interactions, and other types of areas, such as those around workplaces and schools (since these are likely not in one's residential neighbourhood).  Perhaps because of the complexity involved, even fewer studies have examined how specific policies and programs may influence physical activity, diet, and obesity at higher levels of social organization (you can find an example here).    Certainly more studies are needed given the weaknesses in the current literature, as well as the dearth of information in some areas. But I would like to put forward another argument.  Increasing the “walkability” and “liveability” of our shared spaces - *may* decrease obesity but will likely help to decrease green house gas emissions. Making it easier for us to get and cook wholesome foods (namely fruits and veggies) that are free of pesticides, antibiotics, and other chemicals, and harder to get meat, as well as processed foods *could* decrease obesity, but could also help to reduce land degradation, pollution of our water sources, and climate change. All of these things are good for our health in ways other than on our waistline.       My argument is that if there is a focus on sustainability, which these changes imply, population and environmental health should follow.  We need to focus on BOTH the diet and physical activity side in order to not only combat obesity, but a myriad of environmental problems and related health ailments like diabetes and asthma.  These changes are complex, don’t happen overnight, and may bring with them a whole set of new problems (the potential problem of denser living leading to a decrease in indoor air quality immediately comes to mind as an example). Nonetheless, I think we need to move towards rigorously implementing and evaluating interventions that increase sustainability – looking to see if they a) improve the environment, b) reduce obesity, or improve lifestyle behaviours, and c) that they do not negatively impact health in other ways (a post for another day). ... Read more »

  • July 12, 2011
  • 10:32 AM
  • 1,539 views

Transgenic mice susceptible to poliovirus

by Vincent Racaniello in virology blog

Yesterday I terminated the last remaining mice in my small colony, including the line of poliovirus receptor transgenic mice that we established here in 1990. Remarkably, I had never written about this animal model for poliomyelitis which has played an important role in the work done in my laboratory. While I was still working on [...]... Read more »

  • July 12, 2011
  • 10:10 AM
  • 2,151 views

No Really – Sitting Is Killing You

by Travis Saunders, MSc, CEP in Obesity Panacea


Earlier this year I posted an infographic on the health impact of sedentary behaviour which has generated plenty of discussion both here and elsewhere.  Many people are understandably skeptical about the relationship between sedentary behaviour and mortality, so I was excited about the recent publication of two recent systematic reviews focusing on just this issue.
The first, published in the American Journal of Preventive Medicine by Karin Proper and colleagues, focused on the prospective association between sedentary behaviour and obesity, CVD and diabetes risk, as well as mortality.  Somewhat surprisingly, they found little evidence that sedentary behaviour was associated with increased body weight or other health risk factors, despite consistent associations between sedentary behaviour and risk of death.  From the paper:
Weight Gain:
Based on the inconsistent findings among the [3] prospective studies identified, there is insufficient evidence for a longitudinal relationship between sedentary behavior and body weight/BMI gain.
Risk of Being Overweight or Obese:
Based on the inconsistent findings among the [4] studies, there is insufficient evidence for the relationship between sedentary behavior and the risk for overweight or obesity.
Increased Waist Girth:
Based on this single study, there is insufficient evidence for the relationship between sedentary behavior and waist gain.
Risk of Developing Diabetes:
Based on the consistent findings of… two low-quality studies, there is moderate evidence for a significant positive relationship between the time spent sitting and the risk for type 2 diabetes.
Risk of Cardiovascular Disease:
Based on the findings of the 4 studies identified, there is insufficient evidence for a significant relationship between sedentary behavior and various CVD risk factors.
Endometrial Cancer:
Based on the inconsistencies found between and within the two studies identified, there is insufficient evidence for the relationship between sedentary behavior andendometrial cancer.
As I said, there’s really not much evidence so far that sedentary behaviour is prospectively linked with these various markers of health.  However, it does seem to be associated with increased risk of death from various causes:
Based on the findings of the two high-quality studies, there is strong evidence for a relationship between sedentary behavior and mortality from all causes and from CVD, but no evidence for the relationship between sedentary behavior and mortality from cancer.
Another review published late last year focused specifically on sedentary behaviour and cancer outcomes.  It’s conclusions were a bit stronger than the review above, but the evidence for a relationship between sedentary behaviour and cancer still seems pretty weak.  From the review:
The literature review identified 18 articles pertaining to sedentary behavior and cancer risk, or to sedentary behavior and health outcomes in cancer survivors. Ten of these studies found statistically significant, positive associations between sedentary behavior and cancer outcomes. Sedentary behavior was associated with increased colorectal, endometrial, ovarian, and prostate cancer risk; cancer mortality in women; and weight gain in colorectal cancer survivors. The review of the literature on sedentary behavior and biological pathways supported the hypothesized role of adiposity and metabolic dysfunction as mechanisms operant in the association between sedentary behavior and cancer.
What’s the take-home message?
Sedentary behaviour seems very likely to be associated with increased risk of all-cause and cardiovascular disease mortality, while the relationship between sedentary behaviour and cancer mortality remain quite speculative.  Interestingly, prospective studies have yet to find much strong evidence linking sedentary behaviour with prospective risk of cardiovascular disease, despite being associated with increased risk of cardiovascular disease mortality.  Clearly there’s still a lot to be worked out here, especially given that so few prospective studies have been performed to date.  Further, 17 of 19 studies in the Proper review used self-report measures of sedentary behaviour, which can be dramatically different from directly measured sedentary behaviour.
The prospective relationships between sedentary behaviour and risk markers is likely to become more clear with time.  In the meantime, it seems reasonably clear that the more you sit, the greater your risk of mortality.
Standing workstation, anyone?
Travis
Proper, K., Singh, A., van Mechelen, W., & Chinapaw, M. (2011). Sedentary Behaviors and Health Outcomes Among Adults American Journal of Preventive Medicine, 40 (2), 174-182 DOI: 10.1016/j.amepre.2010.10.015
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Proper, K., Singh, A., van Mechelen, W., & Chinapaw, M. (2011) Sedentary Behaviors and Health Outcomes Among Adults. American Journal of Preventive Medicine, 40(2), 174-182. DOI: 10.1016/j.amepre.2010.10.015  

  • July 12, 2011
  • 09:27 AM
  • 1,637 views

New Exercise Guidelines Add Neuromotor Domain

by William Yates, M.D. in Brain Posts

Article first published as New Exercise Guidelines Are Here on Technorati.The American College of Sports Medicine (ACSM) recently published an update on their recommendations for exercise.  These guidelines follow an extensive review of the research literature and update guidelines that were previously published in 1998.The guidelines note four specific areas of exercise: cardiorespiratory fitness and reduction in risk of cardiovascular and metabolic disease, maintenance of muscular fitness, flexibility and neuromotor fitness.The guidelines provide a very extensive review of exercise research.  I will summarize the key recommendations by area of exercise:Cardiovascular fitness and reduction in risk of cardiovascular and metabolic risk factors:Moderate intensity aerobic exercise for 30 minutes per day on five or more days per week orVigorous intensity aerobic exercise for 20 minutes per on three or more days per week orA combination of moderate and vigorous aerobic exercise resulting in a total energy expenditure of 500 to 1000 MET minutes per weekThe MET (metabolic equivalent of task) minutes per week is a method of quantifying exercise.   By definition, the amount of energy needed at rest is one MET.  Moderate intensity is assigned activities such as walking that can be rated in the 3 to 6 MET range.  Vigorous exercise (such as jogging or running) is rated at MET levels about 6.  A person walking at a 4 MET level for 200 minutes per week would expend 1000 MET minutes in a week meeting the exercise guidelinesMuscular fitnessResistance training for each of the major muscle groups two or three times per weekFlexibilityComplete a series of flexibility exercises two or more days per week (60 seconds per each of the major muscle and tendon groupsNeuromotor ExerciseExercise focusing on balance, agility and coordination for 20 minutes on two or more days per weekThe benefits and recommendations have been expanded in this version of the ACSM guidelines.  The authors note the growing literature supporting the benefits of exercise such as tai chi and yoga in promoting balance and flexibility.  Balance and flexibility become increasingly important to counteract the effects of aging.  There is more research support for these types of exercise programs to reduce risk of falls and fall-related medical complications in older individuals.The ACSM notes the limited compliance with exercise guideline compliance in the general population.  Although walking is ranked as the more frequency physical activity in adults, less than 10% of walkers meet the weekly guideline threshold for duration and intensity. The ACSM makes some recommendations to increase compliance with the guidelines:Patients and their physicians should work together to develop and monitor customized programsUse behavioral strategies of "goal setting, social support, reinforcement, problem solving and relapse preventionFurther research targeting factors promoting maintenance of exercise compliance over extended periodsThe ACSM has provided a valuable to put together a comprehensive exercise program with benefits in many areas.  Now it's time for more individuals to adopt a healthy lifestyle that includes meeting these recommended guidelines.Photo of women getting exercise by walking from the author's private collection.Garber, C., Blissmer, B., Deschenes, M., Franklin, B., Lamonte, M., Lee, I., Nieman, D., & Swain, D. (2011). Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory, Musculoskeletal, and Neuromotor Fitness in Apparently Healthy Adults Medicine & Science in Sports & Exercise, 43 (7), 1334-1359 DOI: 10.1249/MSS.0b013e318213fefb... Read more »

  • July 12, 2011
  • 09:05 AM
  • 2,326 views

Choosing your partner is only as helpful as the partners you have to choose from

by Jeremy Yoder in Denim and Tweed


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Picking teammates. Original photo by humbert15.When you need partners for some sort of cooperative activity—say, teammates for a game of kickball—you'd probably like to have a choice among several candidates. That lets you weigh considerations about kicking strength and running speed—and who promised to give you his dessert at lunch period—to build a winning team. However, if the other team captain snaps up the good players first, the fact that you have a choice among the others might not make much difference.

Plants and animals looking for mutualists face a similar situation. Being able to choose among possible partners should allow the chooser to work with helpful partners and avoid unhelpful ones, but a new study suggests that in one widespread mutualism the process of choosing between partners can leave the chooser worse off than if it had no choice at all [$a].

Coauthors Erol Akçay and Ellen Simms focus on the effects of partner choice in the mutualism between plants and nitrogen-fixing bacteria—the interaction I'm studying in my current postdoc position, as it happens. All living things need nitrogen, but only some strains of bacteria are able to collect nitrogen from the atmosphere and "fix" it into a form that other organisms can use. Many plants, particularly members of the big and diverse bean family, have evolved to allow nitrogen-fixing bacteria to infect their roots—the plants form a nodule of root tissue around the infection and supply the tissue with sugar for the bacteria to feed on as they fix nitrogen. Eventually the nodule dries up and dies off, and the bacteria are freed into the soil, having multiplied many times over thanks to the food supply from the host plant.


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A plant's root nodules, some cut open to show the interior. Photo by pennstatelive.To see how this choice might work in practice, Akçay and Simms construct a mathematical model of a plant with two nodules. Each nodule produces some level of nitrogen, and recieves some level of sugar from the plant. The plant negotiates with the two nodules in what's called a "war of attrition" game: whichever partner wants a better deal cuts off the exchange of services, and holds out until the cost of losing the service it recieves is greater than the benefit it hopes to gain in the war of attrition.

Rather like ant-defended plants, plants that host nitrogen-fixing bacteria don't seem to screen potential mutualistic bacteria before allowing them to infect their roots. However, after root nodules are established, the success of the mutualism from the perspective of both partners depends on the genetics of each [PDF], and when host plants receive supplemental nitrogen, they put fewer resources into growing nodules [PDF]. Host plants have been observed with different strains of bacteria in different nodules, and some nodules could contain diligent nitrogen fixers while others are full of freeloaders. This may be the point at which the plant has a choice of partners—it can potentially direct sugar to helpful nodules, and cut off unhelpful ones.

Because the plant has two nodules to choose from, it can potentially outlast an uncooperative nodule by relying on the other one. This works if the plant can shunt more resources to the cooperative nodule and recieve more nitrogen from it in return. However, the success of this strategy depends on two traits of the bacteria inhabiting the nodules—how readily they ramp up nitrogen production in response to more sugar, and how stubborn they are in the war of attrition game.

If both nodules are stubborn but responsive to extra sugar, the plant can negotiate with one nodule by giving the other more sugar and receiving extra nitrogen. This lets the plant hold out longer in the war of attrition. On the other hand, nodules that are not responsive to extra sugar but also not very stubborn yield quickly in the war of attrition even though they don't help much in negotiations. In either of these two cases, the negotiations find an equilibrium in which the plant receives a benefit about intermediate between what it would recieve if both nodules were infected by the same strain of bacteria.

However, if the plant hosts a stubborn-responsive bacterial strain in one nodule and a yielding-unresponsive strain in the other, it finds itself in a trap: the yielding-unresponsive strain is no help in negotiation against the stubborn-responsive strain, and the help provided by the stubborn-responsive strain isn't an advantage in negotiating with the yielding-unresponsive strain. Over successive negotiations, the stubborn-responsive strain can ratchet up the sugar it extracts from the plant, and the plant ends up worse off than it would be if the two nodules were identical.

Just like humans haggling in a marketplace, the outcome of the interaction depends strongly on whether the other party plays along as expected.



Akçay and Simms find a way out of this trap by adding another wrinkle to the model. Much like the contract-theory models of mutualism I've discussed before, they modify the model to allow cooperative nodules to benefit from being cooperative. This makes a good deal of intuitive sense—if a nodule provides a better deal to the plant, the plant can potentially grow more leaves to produce more sugar, which would allow it to offer a better deal to the bacteria it hosts. Akçay and Simms call this "partner fidelity feedback," and they find that, if it is sufficiently strong, it can allow the plant to out-negotiate a stubborn strain of bacteria.

Although it has a good deal of intuitive appeal, the model presented by Akçay and Simms does a fair bit of speculating in the absence of data. This is also a problem for the contract-theory model, and really all models of this widespread and important interaction. We know a great deal about the chemical details of plants' interaction with nitrogen fixing bacteria. However, we don't have a good sense of whether and how plants can redirect resources among nodules to haggle with the bacteria they host, and we don't know whether and how bacteria could adjust their behavior to haggle with the plant. Akçay and Simms devote a big section of their online appendix [$a] to discussing just this point.

To figure out what's going on inside those nodules, we need to determine how different models of interaction between plants and their bacterial mutualists may shape patterns in things that are easier to observe—both in the compatibility between plant genotypes and bacterial strains in greenhouse tests, and in the broader population genetics of both partners.

References

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  • July 12, 2011
  • 08:43 AM
  • 1,066 views

Update on triple negative breast cancer

by Sally Church in Pharma Strategy Blog

One of the challenges of triple negative breast cancer is that it is defined by what it is not (ie ER/PR-, HER2-), rather than what it is.  This broad subgroup of breast cancer is therefore more heterogeneous in nature than … Continue reading →
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  • July 12, 2011
  • 08:36 AM
  • 2,544 views

Vaginal 'probiotics' may protect against HIV transmission

by Connor Bamford in The Rule of 6ix

According to WHO data, 2009 saw 33.9 million people worldwide infected with the human immunodeficiency virus -  HIV and of these, 1.8 million died from AIDS while 2.9 million were newly infected with the virus. This leaves a year-on-year increase of just over 1 million HIV positive people of which, many of these will go on to pass the virus. Therefore any strategy to eliminate HIV from the human population will have to aim at both treating those already infected as well as preventing new viral transmission and if this is achieved, HIV infection worldwide would dramatically decrease with every year, severely reducing the global health burden caused by this viral pandemic. The only problem is, how can we successfully prevent transmission?



Despite a significant decrease the number of people infected by HIV continues to grow year on year

HIV entry and pathogenesis - where and how can we target it?

One of the major routes of HIV transmission is through sexual activity: an HIV positive person will be carrying many copies of the HIV genome within their cells and in turn these will be able to generate new infectious virus particles. These virions - either present in blood or semen - may be mechanically transferred from infected to uninfected people during sexual activity and many immune cells (Langerhans cells, macrophages and intraepithelial CD4+ T cells to be precise - see below) lining and within the mucosal epithelial surfaces of the reproductive tract are the initial target cells for HIV entry into the human body. It is here that the cells are exposed to the virus through sexual contact, facilitating virus uptake and initial infection then allowing the virus to spread within the body and potentially set up the chronic infection that may develop into AIDS.

HIV entry via immune cells within the vaginal mucosa and spread to systemic lymphoid organs. Miller, 2007.

Many potential strategies are currently in development which aim at preventing person-person transmission during sexual activity through the inhibition of HIV particle transfer. This is the reason why condoms - male and female - are so effective. As the authors of the paper outlined below highlight the requirements of such a strategy:In many cultural settings, women need a product that can be used covertly without obtaining the permission of their sexual partner. In addition, the cost of HIV prevention must be affordable to the developing world. Thus, there is still a need for products that block HIV transmission, are safe and easy to use, and are coitally independent, discreet, and cost effective. Bacterial symbiosis to the help

All being so, our bodies are not completely defenseless when it comes to preventing sexually transmitted infections, including HIV; we have multiple tricks up our sleeves and one of which is through a form of bacterial symbiosis. The human reproductive tract is covered in a bacterial biofilm composed of a few species of bacteria, predominantly Lactobacilli. These microbes regulate vaginal biology and aid in the protection against variable infections through the formation of a physical barrier and through alterations in pH. But of course it isn't enough and as I mentioned earlier, people are all too often getting infected with HIV. Yet what if we could enhance these bacterial defenses through genetically engineering those bacteria that natural colonise the reproductive tract? This is exactly what a recently published paper in Mucosal Immunology reports -  the development of a novel genetically engineered live bacterial strain expressing an anti-HIV protein that can be easily applied to the vagina and prevents HIV transmission


Normal tissue properties A) and Presence of anti-HIV protein CV-N

The group had previously generated an engineered strain of Lactobacillus jensenii (termed:1153-1666) that expressed and secreted a modified Cyanovirin-N (CV-N) protein. This protein has been shown to have a broad inhibitory activity against a range of HIV-1 strains and provide protection from infection in a non-human primate model of HIV through inhibiting virus entry into those target immune cells - it is also highly potent and non-toxic. To establish the potential for administering this bacteria in humans, the group inoculated the vaginas of non-human primate macaques on a regular basis and achieved stable colonisation along with expression of the antiviral protein in the fluid lining the tract; the recombinant L. jensenii was detected along the epithelium while no tissue changes were observed and no untoward inflammation was detected, all indicating the safety of this strategy.


in vitro HIV inhibition with non-recombinant (left) and recombinant (right) bacteria

So far, the ability of this recombinant bacteria to inhibit HIV infection has not been addressed so later it was assessed through the use of an in vitro model that accurately portrays the physical and biological architecture of the human vagina as well as the macaque model that uses chimeric human/simian immunodeficiency virus infection. Colonization of the in vitro vaginal tract with the non-recombinant bacteria resulted in a 23% reduction in HIV infection compared to the control while inoculation with the CV-N expressing strain gave 72% inhibition (see above). Groups of macaques were then treated with an antibiotic to remove any endogenous Lactobacillus colonizing their vaginal tract and were subsequently inoculated repeatedly with the recombinant strain. These monkeys were then repeatedly challenged with the virus in a manner similiar to what would happen under natural human conditions and the ability of the virus to infect each animal was assessed over time. This strategy reduced the infection rate by nearly 63% (see below).



Macaque challenge outline and results of bacterial colonization protection


 This group has generated a bacteria... Read more »

Lagenaur, L., Sanders-Beer, B., Brichacek, B., Pal, R., Liu, X., Liu, Y., Yu, R., Venzon, D., Lee, P., & Hamer, D. (2011) Prevention of vaginal SHIV transmission in macaques by a live recombinant Lactobacillus. Mucosal Immunology. DOI: 10.1038/mi.2011.30  

  • July 12, 2011
  • 08:02 AM
  • 1,667 views

Babies prefer Picasso

by BPS Research Digest in BPS Research Digest



Still life with guitar by Picasso [c. www.pablo-ruiz-picasso.net]
Psychologists who study art appreciation have their work cut out. How does one begin to untangle cultural influences from more basic perceptual factors - the cache from the contours? Well one way is to study babies, because they're obviously too young to know about cultural fads and artistic reputations.

Trix Cacchione and her team at the University of Zurich presented nine-month old babies with paintings by the cubist painter Picasso and the impressionist Monet. Their first aim was to see if the babies could tell the difference between the two painting styles. They did this by continually presenting the babies with different paintings by one of the artists until they grew bored (known as "habituation") and then seeing if the babies treated the sight of a painting by the other artist as somehow different, and therefore more worthy of their attention. The finding here was that babies who'd habituated to Monet were thereafter more attracted to a painting by Picasso, as revealed when new paintings by each artist were presented together side by side. There was clearly something novel about a Picasso painting that they perceived and found stimulating, which led them to look at it more. However, the reverse wasn't true. Babies habituated to Picasso preferred to look at yet another Picasso painting rather than enjoy the greater novelty of a Monet.

Next the researchers checked the babies could distinguish between different paintings by the same artist. They found that babies habituated to one particular Picasso were attracted to a new Picasso more than a repeat. Ditto for Monet - the babies preferred a new Monet to a familiar old one.

So why did the babies prefer to look at yet another Picasso, even after they'd seen loads of them, rather than enjoy the novelty of a Monet? The implication is that the appeal of a Picasso overpowers the novelty of a Monet. There's clearly something about Picasso, but what is it?

Cacchione's team looked at a whole range of factors: Picasso's use of vivid colours, sharp contours, and his use of squares and other figurative elements (Monet pictures, by contrast, are more subtle and realistic). But each time the researchers removed one of these elements, for example by using black and white pictures of the paintings, the babies still preferred Picasso.

The most likely explanation then is that it's something about these elements in combination that appeals to babies. One further factor, which the current study didn't look at, is luminance or "perceived lightness". The researchers said it's possible that babies prefer Picasso because of the greater luminance of his paintings. Crucially, luminance is processed mostly by the dorsal visual stream (the "where pathway"). This would fit with the idea that babies don't yet have a fully developed visual system - in particular the ventral stream (also known as the "what pathway") is immature.

"Many of Monet's paintings have so little luminance contrast that it is impossible to recognise their elements on the basis of dorsal processing," the researchers said. "It is possible that infants preferred paintings by Picasso, because they were easier to process and afforded the most stimulation to their still developing visual system."

A final possibility is that there's something about Monet that babies don't like, rather than there being something particularly appealing about Picasso. Only further studies with more babies and different artists will get to the truth of why there appears to be something about Picasso.
_________________________________

Cacchione, T., Möhring, W., and Bertin, E. (2011). What is it about Picasso? Infants' categorical and discriminatory abilities in the visual arts. Psychology of Aesthetics, Creativity, and the Arts DOI: 10.1037/a0024129

This post was written by Christian Jarrett for the BPS Research Digest.

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  • July 12, 2011
  • 08:00 AM
  • 1,378 views

Tuesday Crustie: A fifty year wait for a name

by Zen Faulkes in NeuroDojo

This picture appeared in a wonderful gallery in The Guardian about life on the island of New Guinea a couple of weeks ago.


But in the original paper, you will find another spectacular picture. And before you ask, yes, this is actually the same species:


This second picture is probably more representative of the colouration of the species in the wild. In the paper describing it formally, the authors say its colour is, “Pinkish to orange and sometimes pale yellow.” My understanding is that many species of crayfish have a recessive gene that can result in this bright blue colour. This means that it is easy for pet owners to get a true-breeding strain if you have two individuals with the trait.

The story of the discovery of this species sows the long and roundabout route of basic species descriptions. These species started to show up in the pet trade in Europe and Japan (where have I heard that story before?), with information coming that there were collected in the Indonesian province of Irian Jaya on New Guinea.

The authors went into the extensive archives of a natural history museum in the Netherlands... and found the museum had samples of this unnamed species that were collected in 1952. These wonderful animals have been waiting for a science to name and describe them for over fifty years.

The museum the specimens were found was where the late carcinologist Lipke Holthuis worked. (He was eulogized at The Crustacean Society meeting I attended last month.) The crayfish now bear his name, Cherax holthuisi.

The text that accompanied the Guardian gallery article scares me, though.

Although new to science, wholesalers have already introduced the species to the European and Japanese pet market; however, the biology of the species in the wild, its distribution range, its conservation status and its value to local communities remain unknown.
Grabbing crayfish and shipping them as pets around the world when we are ignorant of their basic biology natural habitat is dangerous and irresponsible. It’s reasons like this that I started the Craywatch project.

Reference

Lukhaup C, & Pekny R (2006). Cherax (Cherax) holthuisi, a new species of crayfish (Crustacea: Decapoda: Parastacidae) from the centre of the Vogelkop Peninsula in Irian Jaya (West New Guinea), Indonesia. Zoologische Mededelingen 80(1): 101-107. http://www.repository.naturalis.nl/document/41228... Read more »

Lukhaup C, & Pekny R. (2006) Cherax (Cherax) holthuisi, a new species of crayfish (Crustacea: Decapoda: Parastacidae) from the centre of the Vogelkop Peninsula in Irian Jaya (West New Guinea), Indonesia. Zoologische Mededelingen, 80(1), 101-107. info:/

  • July 12, 2011
  • 07:38 AM
  • 1,102 views

Innovation is seeing round the corners

by Pieter Droppert in Biotech Strategy Blog

Innovation involves insight that allows you to see around the corners. That’s the perspective according to Andrew Marks, Professor of Physiology & Cellular Biophysics at Columbia University Medical Center, who recently wrote a Commentary on Innovation in Science Translational Medicine. … Continue reading →... Read more »

  • July 12, 2011
  • 06:40 AM
  • 1,543 views

Visual feedback for training novel coordinations

by Andrew Wilson in Notes from Two Scientific Psychologists

The key feature of coordinated rhythmic movements is that not all coordinations are stable. Most other rhythms can be learned, however, which is why we can have jazz drumming. People have been training participants to perform novel coordinations (especially 90°, the least stable rhythm without training) for years now, and have been asking all the standard learning questions - how long does learning take? Does it transfer to other coordinations? The first real studies on learning were by Kelso and Zanone (Kelso & Zanone, 2002; Zanone & Kelso, 1992a, b, 1997). I briefly reviewed the results of these studies here, which have lead to to the dynamic pattern hypothesis. This account describes stable states as attractors in a state space defined by relative phase as the order parameter, and learning is the creation of a new attractor centred on the target novel phase. This account ran into problems quite quickly but is still alive and kicking in a modified form; stability is the governing principle now, and from this perspective the feedback displays used for training don't matter so long as they support stable action. However, from our perception-action standpoint, the feedback displays matter a lot, because these are what's providing the perceptual information about the coordinated movement. Early learning studies all used some kind of transformed feedback, which we could never use because it altered the overall perception-action dynamic. In order to look at action learning directly, we needed a new form of feedback. So I invented one.Forms of Transformed Visual Feedback1. Visual MetronomesFigure 1. Visual metronomeThe first form of feedback was the visual metronome, used by the Kelso & Zanone studies, and is still used by Zanone. All it is is... Read more »

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