Post List

  • June 7, 2011
  • 10:19 AM

Internet-Based Health Interventions: What Works?

by pennydeck in Feedback Solutions for Obesity

Many health behaviour interventions and treatment programs increasingly use web-based delivery platforms, capitalizing on the 80% of internet users in the US that search online resources for health information (1). Internet programs represent a relatively new way to deliver interventions … Continue reading →... Read more »

  • June 7, 2011
  • 09:38 AM

Morphological response of songbirds to 100 years of landscape change in North America

by Roger Jovani in Birds and Science

It is generally recognized that pointed wings allow a faster flight than rounded wings and hence, this shape has been favoured in migrating species or subpopulations. On the other side, rounded wings allow more manoeuvrability, being favoured in closed habitats....... Read more »

  • June 7, 2011
  • 09:05 AM

Freeloading caterpillars get in the way of plant-ant mutualism

by Jeremy Yoder in Denim and Tweed

.flickr-photo { }.flickr-framewide { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:100%;}.flickr-caption { font-size: 0.8em; margin-top: 0px; } Cecropia obtusifolia provides food for ants that come and protect it—unless caterpillars get there first. Photo by wallygroom.Imagine you need a team of security guards. To find them, you decide not to place an ad in the local paper or on Craigslist. Instead, you build an apartment complex next to your home, complete with a full-service cafeteria providing free hot meals 24 hours a day. You leave the front doors unlocked, then hope that anyone who shows up to live in the apartments will also keep an eye on your home.

If you took that strategy to protect your assets, you'd have to be crazy. But that's pretty much what ant-protected plants do all the time. They grow hollow structures called domatia, secrete nectar from special structures, and even produce tasty and nutritious "food bodies." Then they wait for ants to move into the domatia, eat the nectar and the food bodies, and hopefully chase away anything that might want to do the plant harm. The crazy thing is, it works.

Well, it mostly works.

One gap in the ant-protection mutualism is the period when an ant-protected plant hasn't grown big enough to support a whole colony of ants. In this early stage, ants won't colonize the plant, but other insects might be quite happy to take the rewards that are already being offered. That's exactly what larvae of the butterfly Pseudocabima guianalis do—they make themselves at home on unprotected ant-plants.

The ant-plant Pseudocabima caterpillars target is Cecropia obtusifolia, a shrubby Central American tree that relies on ants in the genus Azteca for protection. Azteca ants make vicious and well-coordinated bodyguards. Here's video Ed Yong posted last year, showing a bunch of the ants flushing a hapless moth into an ambush.

However, Cecropia saplings can't produce enough food to support a colony of ants until the plants grow to more than a meter tall. What's too little for thousands of ants is a feast for a Pseudocabima caterpillar, however. Each caterpillar builds a silk shelter around a region of the plant that grows food bodies, and settles in to eat. As it grow larger, the caterpillar moves into a domatium near its original shelter, covering the entrance hole with silk. Finally the caterpillar pupates inside the domatium, emerging as an adult to lay eggs on another unprotected Cecropia plant.

Eventually the Cecropia saplings grow large enough to attract ants, who run off the caterpillars. However, as the paper I linked to above describes, the caterpillars seem to be able to resist an ant colony's establishment on the plant—the silk shelters prevent ants from getting to the best sources of food. Cecropia saplings occupied by caterpillars didn't seem to suffer more herbivore damage than ant-protected plants, but they did grow more slowly over the course of several years' observations. Caterpillar-infested Cecropia plants were also more vulnerable to infection by a fungus, which the ants removed quite effectively.

Interestingly, though, caterpillar-infested plants also produced less food than those guarded by ants. This is a point of circumstantial evidence for a new model of mutualism I wrote about earlier this year, in which cheating is reduced or prevented when a host like Cecropia better mutualists help create better rewards. An ant-protected plant can divert more resources to feeding its tenants, so their work rewards itself. However, Pseudocabima caterpillars are glad to take the lower level of rewards that Cecropia plants offer up to all comers.

In other words, if you're going to give out free lunches, you can't really expect everyone who eats to pay you back.


Roux, O., Céréghino, R., Solano, P.J., & Dejean, A. (2011). Caterpillars and fungal pathogens: Two co-occurring parasites of an ant-plant mutualism. PLoS ONE, 6 : 10.1371/journal.pone.0020538

... Read more »

Roux, O., Céréghino, R., Solano, P.J., & Dejean, A. (2011) Caterpillars and fungal pathogens: Two co-occurring parasites of an ant-plant mutualism. PLoS ONE. info:/10.1371/journal.pone.0020538

  • June 7, 2011
  • 08:00 AM

The Warmth of the Heart Prevents Your Body from Rusting [#accessibility #a11y]

by Simon Harper in Thinking Out Loud

It seems to me we have got into a habit of using ageing as a proxy term for combinatorial disability, its inaccurate and we should stop it. Continue reading →... Read more »

Peter G. Fairweather. (2008) How older and younger adults differ in their approach to problem solving on a complex website. Proceedings of the 10th international ACM SIGACCESS conference on Computers and accessibility, 67-72. info:/

  • June 7, 2011
  • 08:00 AM

The Warmth of the Heart Prevents Your Body from Rusting [#accessibility #a11y]

by Simon Harper in Thinking Out Loud

It seems to me we have got into a habit of using ageing as a proxy term for combinatorial disability, its inaccurate and we should stop it. Continue reading →... Read more »

Peter G. Fairweather. (2008) How older and younger adults differ in their approach to problem solving on a complex website. Proceedings of the 10th international ACM SIGACCESS conference on Computers and accessibility, 67-72. info:/

  • June 7, 2011
  • 08:00 AM

Tuesday Crustie: Jonah

by Zen Faulkes in NeuroDojo

As I’m in Hawaii today to attend The Crustacean Society meeting, it seems only fitting to feature a species that is, while not new to science, new to Hawaii. This is Albunea bulla, a sand crab. Regular readers might recognize sand crabs as a group close to my heart, because they were the subject of my doctoral research.

But when you read the text of the paper, you could be forgiven for missing the cool story of how the sample that proved this species was found in Hawaiian waters:

Material examined. U.S.A., Hawaii: 200 fathoms (365.8 m), ex opakapaka a.k.a. crimson jobfish (Pristipomoides filamentosus (Valenciennes)) Little Brooks Bank (ca. 24°–24°15’N, 166°45’–167°W), northwestern Hawaiian Islands, coll. Capt. W. Strickland on F/V Fortuna, 11 Apr 2005: 1 male, 17.5 mm cl
(BPBM S12265).
You might suspect something was up when you hit this understated little phrase:

The condition of the present specimen is remarkably good, considering the source(.)
Finally, it sinks in:

(T)he fact that the fish species from which the Hawaiian specimen of A. bulla was removed has been found generally from 90–360 m depth (Allen 1985) suggests that perhaps the crab was eaten at shallower depths and transported intus piscis to the depth at which the fish was caught.
That’s right, they pulled the crab out of the stomach of the fish that ate it!

And, by the way, this proves that anything can sound classy in Latin. Compare:

“intus piscis” — Ooooh, sounds elegant!
“fish guts” — Eeeew, that’s disgusting!

I think in one of my papers, I suggested that one of the big advantages of being a digging species is being hidden from predators.

Apparently, that advantage isn’t as big as I thought.


Boyko CB. 2010. New records and taxonomic data for 14 species of sand crabs (Crustacea: Anomura: Albuneidae) from localities worldwide. Zootaxa 2555: 49-61... Read more »

Boyko CB. (2010) New records and taxonomic data for 14 species of sand crabs (Crustacea: Anomura: Albuneidae) from localities worldwide. Zootaxa, 49-61. info:/

  • June 7, 2011
  • 06:43 AM

The neuroscience of batman, or how the human brain performs echolocation

by BPS Research Digest in BPS Research Digest

Over the last few years it’s become apparent that humans, like bats, can make effective use of echolocation by emitting click sounds with the tongue and listening for the echoes that result. Now a team led by Lore Thaler at the University of Western Ontario has conducted the first ever investigation into the neural correlates of this skill.

Thaler and her colleagues first had to overcome the practical challenge of studying echolocation in the noisy environment of a brain scanner, in which participants are required to keep their heads still. The researchers established that two blind, experienced echo-locators, EB and LB, were able to interpret with high accuracy the recordings of tongue clicks and echoes they’d made earlier, and so this form of passive echolocation was studied in the scanner.

Among several remarkable new insights generated by the research, the most important is that EB and LB exhibited increased activity in their visual cortices, but not their auditory cortices, when they listened to clicks and echo recordings taken outside, compared with when they listened to the exact same recordings with the subtle echoes omitted. No such differential activity was detected among two age-matched, male sighted controls.

The finding suggests that it is the visual cortex of the blind participants that processes echoes, not their auditory cortex. This visual cortex activity was stronger in EB who was blind from an earlier age than LB, and is more experienced at echolocation. However the echolocation skill of both blind participants is remarkable. Both are able to cycle and they can identity objects, and detect movement. EB, but not LB, showed evidence of a contra-lateral pattern in his echo-processing brain activity, just as sighted people do with the processing of light. That is, activity was greater in the brain hemisphere opposite to the source of stimulation.

Just how the visual cortex extracts meaningful information from subtle echo sounds must await future research. The researchers best guess is that the relevant neurons perform ‘some sort of spatial computation that uses input from the processing of echolocation sounds that was carried out elsewhere, most likely in brain areas devoted to auditory processing.’ Establishing the functional role of the cerebellar processing that was also differentially activated by echo sounds in the echo-locators must also await future research.

‘… [O]ur data clearly show that EB and LB use echolocation in a way that seems uncannily similar to vision,’ the researchers concluded. ‘In this way, our study shows that echolocation can provide blind people with a high degree of independence and self-reliance in their daily life. This has broad practical implications in that echolocation is a trainable skill that can potentially offer powerful and liberating opportunities for blind and vision-impaired people.’

If this research has piqued your interest in echolocation, a previous research paper on the topic by Antonio Martinez and his co-workers explained that anyone, blind or sighted, is able to learn the skill. In fact they said that after two hours practice a day for two weeks you should be able to recognise blindfolded whether there is an object in front of you or not.

L Thaler, S Arnott, and M Goodale (2011). Neural Correlates of Natural Human Echolocation in Early and Late Blind Echolocation Experts. PLOS One DOI: 10.1371/journal.pone.0020162

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

... Read more »

  • June 7, 2011
  • 06:37 AM

Perceiving long distances in action scaled units

by Andrew Wilson in Notes from Two Scientific Psychologists

I have so many things I need to write up just now, but it's been a struggle finding the time. I hope to post on Chemero's last chapter, task-specific devices, calibration and some new coordination data soon. In the meantime, I thought I'd take advantage of the fact that I'm reading some new articles on an interesting topic, and I wanted to organise some thoughts and see if anyone had any comments!Perception is action-scaledTraditional theories of perception claim that we perceive the world in generic terms, and must transform that perception into a task relevant variable after picking the information up. The ecological suggestion is that the act of perception itself is directly scaled in action-relevant units, and that this perception will therefore be task-specific. In order to directly perceive action relevant properties (i.e. affordances) perception must be smart (think of the analogy of the polar planimeter). We are capable of perceiving the distance of things in the world; but we don't perceive them as being '6m away'. Instead, the system is interested in how to reach for an object, so you need to calibrate your perception of distance in terms of, say, arm length units. Calibration is the process of placing a measurement on a scale, and the ecological approach has been interested in action relevant scales such as arm lengths (for reaching; Mon-Williams & Bingham, 2007) and leg lengths (for stair climbing; e.g. Warren, 1984). One of Chemero's points is relevant here; body scale is probably only a proxy measure for ability to perform the action and the real action scale the system is using (the effectivity) will be more complicated. But body scale is mostly where the field is at right now.Perceiving distances beyond reach space  I'm currently interested in distance perception and the scaling it uses because I've begun collaborating with Arthur Zhu and Geoff Bingham on their throwing research (one paper of which I blogged here). We ran some studies in parallel this year on learning to throw to hit a target at 10m, and one of the interesting questions lurking in here is, how are people perceiving the distance to the target? Learning to throw accurately to a specific distance entails learning to produce a useful combination of release angle and release velocity; but these release parameters are the last chance you have to affect the ball's trajectory and so you must select these parameters on the basis of the perceived distance to the target (amongst other things). At 10m, your eyes are parallel and hence there is little information from this geometry about where things are in space. You need to visually perceive the location of the target along the floor from you, and you need to perceive this in throwing relevant units.There are two basic suggestions for action relevant scaling over long distances: eye height units (Sedgwick, 1986) and effort (e.g. Proffitt, 2008). Eye height is potentially quite useful, because it's always available in optic flow. The suggestion here is that you treat one eye-height as a unit, and perceive distance on a scale using that unit; 10m would then be some number of eye heights away. This is fine, and there is some evidence that eye-height matters, but it's not clear what is action relevant about it. If you wish to perceive the affordances of a spatial layout related to distance, what is it about eye-height that affects your ability to effect that affordance?Effort seems to be more in line with Chemero's suggestion that 'ability to perform the action' is the relevant dimension to go looking. However, it's terrible vague and hand-wavy. Essentially, the suggestion from Proffitt's group is that when viewing a space, your perception of those distances is scaled in terms of the amount of effort required to perform the task you're about to do. If you're about to walk the distance, your perception is scaled to locomotor effort; if you're about to throw something the distance, your perception is scaled to throwing effort. Perceived distance is therefore directly scaled to action relevant units at the time of perception by virtue of you being one task-specific device rather than another. When and how are spatial perceptions scaled?To test this idea, Witt, Proffitt & Epstein (2010) ran a simple study to tease apart when your visual perception of distance is scaled (at the time, or by a post-perceptual cognitive process) and to demonstrate task-specific effects on this scaling. There were two groups; the first was told they were going to walk to a target 6m or 8m away, the second were told they were going to throw to that target. The two groups then walked on a treadmill; this recalibrates the relationship between walking and optic flow such that walking at a set speed produces minimal optic flow, instead of flow at the set speed, because you aren't actually translating through the environment. This makes people feel that they need to expend more effort to walk a given distance (because effort now isn't producing much flow, you have to increase effort to get the appropriate flow to suggest you've moved far enough). Both groups were then asked to walk blindfolded to the target distance (so the throwing group were now doing a different action).The hypothesis was this: if you viewed the target at 6m with the intention of walking to it, your perception of the distance was scaled according to the effort required to locomote that far. If you recalibrate this scale with the treadmill so that more effort is required to cover that distance, and you are then asked to walk blindfolded until you think you have covered the distance, you will expend more effort and end up walking further than you would have. If you viewed the distance with the intention of throwing an object that far, your perception would be scaled in terms of the effort required to throw that far; this effort is not recalibrated by the treadmill experience and hence, when asked to instead walk the distance, you won't expend extra effort. If perception is not action scaled at the time of perception (pre-treadmill) but rather transformed in a post-perception cognitive process, then both groups should show the effect of the treadmill.The results showed that for both distances, walkers always blindwalked further than throwers-turned-walkers if there was a treadmill manipulation. This demonstrates that distance perception is action-scaled at the time of perception, relates to effort, and is task-specific.ThoughtsThere are some devilish details to worry about:Blind walking is designed to be an action measure of your visual distance perception at time t, in the absence of the ability to refine and update that perception with ongoing visual perception of the scene. It gets used quite a bit, and seems to work ok. It is, however, a little noisy and over longer distances people begin to get conservative and undershoot distances. This doesn't mean they thought the distance was shorter than it was, it can simply mean that, under uncertainty, they are playing it safe. In this study, at 8m, both groups undershot in the control condition and the throwers-turned-walkers did so in the treadmill study. So blindwalking is a complicated measure of what you thought the distance was.They tried this in reverse (trying to get walkers-turned-throwers to overshoot because of the treadmill experience) but blind-throwing is even more variable than blind-walking, so nothing came out. I'm interested in other changes in people's locomotion: does their stride length change? Stride frequency? The speed and hence the time taken to walk a given distance? And how do these relate to the treadmill activity? What about other measures of effort (e.g. VO2 max?)Other thoughts:If throwers-turned-walkers perceived the distance to the target in terms of throwing effort, why were they then able to use this information to walk quite accurately?  What does effort mean, anyway? What is the informational basis for this? I can kind of see a story about locomotion, where over the course of the day and a... Read more »

Witt JK, Proffitt DR, & Epstein W. (2010) When and how are spatial perceptions scaled?. Journal of experimental psychology. Human perception and performance, 36(5), 1153-60. PMID: 20731519  

  • June 7, 2011
  • 03:00 AM

The digital democracy of the internet and the publicity of openness

by SAGE Insight in SAGE Insight

A very popular blog: the internet and the possibilities of publicity From New Media & Society This article outlines how the mediums of traditional broadcast and the internet have different publicity possibilities. It is clear that the structure of the internet makes it particularly good at developing a publicity of openness and traditional media is [...]... Read more »

Brenton J. Malin. (2011) A very popular blog: The internet and the possibilities of publicity. New Media , 13 (2). info:/

  • June 7, 2011
  • 01:18 AM

Featured - The results are in, and I got nothing!

by Rift in Psycasm

This post is being written primarily for UQPsycBlog, a blogging collective written by PhD students at UQ, which primarily focuses on a day-in-the-life... Given that I kinda rub shoulders with a number of the contributers to the blog, and I intend to pursue a Phd, I've been asked to contribute...
And so here it is, a follow up to 'My Experimental Virginity' and 'Willful Self-De; (read more)

Source: Psycasm - Discipline: Psychology... Read more »

  • June 6, 2011
  • 11:58 PM

The Downside of Nano: Pregnancy Complications

by Paige Brown in From The Lab Bench

A recent article in Nature Nanotechnology investigates the potential risks of nanomaterials, specifically various sized silica and titanium dioxide nanoparticles, for causing pregnancy complications in mice. With up to 15% of human pregnancies in the United States being affected by poor fetal growth due to defects in or damages to placental tissue, researchers argue that nanomaterials found in many drug formulations as well as several food and women's cosmetic products deserve a careful investigation.... Read more »

Yamashita K, Yoshioka Y, Higashisaka K, Mimura K, Morishita Y, Nozaki M, Yoshida T, Ogura T, Nabeshi H, Nagano K.... (2011) Silica and titanium dioxide nanoparticles cause pregnancy complications in mice. Nature nanotechnology, 6(5), 321-8. PMID: 21460826  

  • June 6, 2011
  • 09:16 PM

Plesiosaurs, the Beautiful Bottom-Feeders

by Laelaps in Laelaps

In 1821, British geologists Henry De la Beche and William Conybeare presented a bizarre, previously-unknown fossil creature to their colleagues in the Geological Society of London. They called their monster Plesiosaurus. A paddle-legged marine reptile akin to the recently-discovered, shark-shaped animals known as ichthyosaurs, the new animal was cast as “a link between the Ichthyosaurus [...]... Read more »

McHenry CR, Cook AG, & Wroe S. (2005) Bottom-feeding plesiosaurs. Science (New York, N.Y.), 310(5745), 75. PMID: 16210529  

  • June 6, 2011
  • 08:01 PM

The Monarch Butterfly:Emmisary of 3 Nations

by Kimberly Moynahan in Endless Forms Most Beautiful

An exciting thing happened a couple weeks ago. I got email from Donald Davis, one of the leading Monarch Butterfly aficionados in Ontario, asking me if I was the Kimberly Gerson who tagged a monarch butterfly in Whitby Ontario, in September of 2006. If so, he went on to say, my tag had been recovered [...]... Read more »

  • June 6, 2011
  • 06:15 PM

Generating Functional Neurons Directly from Human Fibroblasts

by Michael Long in Phased

Connective tissue cells have been directly converted into functional neurons, avoiding stem cell intermediates likely to be carcinogenic, an important step towards replacing cells lost in Parkinson's disease.... Read more »

Ulrich Pfisterer, Agnete Kirkeby, Olof Torper, James Wood, Jenny Nelander, Audrey Dufour, Anders Björklund, Olle Lindvall, Johan Jakobsson, & Malin Parmar. (2011) Direct conversion of human fibroblasts to dopaminergic neurons. Proceedings of the National Academy of Sciences. info:/10.1073/pnas.1105135108

  • June 6, 2011
  • 06:00 PM

A Whistle of Surprise

by Diane Kelly in Science Made Cool

A caterpillar with an unusual aural defense mechanism.... Read more »

  • June 6, 2011
  • 04:55 PM

Osteochronology and the Berenstain Bears

by Kristina Killgrove in Powered By Osteons

Actually, Papa Bear, humans are a bit similar to trees.... Read more »

  • June 6, 2011
  • 04:54 PM

Were Dinosaurs Nocturnal, Diurnal, or Both?

by Allison in Dormivigilia

A recent report in Science compared eye morphologies to compare the vision type (scotopic vs. photopic vs. mesopic) and ecology (herbivore vs. predator vs. flyer) of Mesozoic archosaurs (the most notorious being the Velociraptor), suggesting intimate evolutionary links between physiological/anatomical make-ups and behavior as far back as the Mesozoic era. ... Read more »

  • June 6, 2011
  • 04:30 PM

Back Pains, Rubbery Brains, Doubts Remain

by Lorimer Moseley in BodyInMind

A while back Ben Wand blogged here about grey matter density changes in the brain and chronic pain. A new study, published in the Journal of Neuroscience by David Seminowicz et al tells what appears to be a similar story.... Read more »

  • June 6, 2011
  • 03:24 PM

How to Recycle Cancer GWAS Data

by Rob Mitchum in ScienceLife

In the 2000s, a new kind of genetic experiment was born: the genome-wide association study, or GWAS. If geneticists could recruit enough people with a particular disease and compare them to an equal number of disease-free controls, they believed GWAS would point the way to common gene variants associated with disease risk and novel biological [...]... Read more »

  • June 6, 2011
  • 02:07 PM

Monitoring your sleep patterns

by Charles Harvey in Charles Harvey - Science Communicator

It’s 3am. The cold light of my computer screen illuminates my face, highlighting the bags that are forming under my eyes and casting disturbing shadows around my bedroom. You might think that I was engaged in something incredibly important to keep me up so late. But no, the truth is, I am unable to sleep and resign myself to touring the bizarre offerings the internet presents only early in the morning.... Read more »

Cajochen C, Frey S, Anders D, Späti J, Bues M, Pross A, Mager R, Wirz-Justice A, & Stefani O. (2011) Evening exposure to a light-emitting diodes (LED)-backlit computer screen affects circadian physiology and cognitive performance. Journal of applied physiology (Bethesda, Md. : 1985), 110(5), 1432-8. PMID: 21415172  

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