Science-- there's something for everyone

Friday, January 31, 2014

Don’t eat right for your type

In 1996, P.J. D’Adamo’s book Eat Right For Your Type proposed that, for optimum health, people should adopt diets specific for their ABO blood type. If you thought that was nonsense, you’re right! While the various diets proposed in the book can be healthy changes, they are equally good for everyone regardless of blood type.
University of Toronto researchers led by Ahmed El-Sohemy put the blood type diet myth to rest by giving 1455 young adults various diets. People with blood type A did benefit from the type A diet (lots of grains, fruits and vegetables) with lower BMIs, insulin and cholesterol, but so did people with other blood types. Similarly, the type O diet (lots of meat, little or no grain) was associated with lower triglycerides for everyone, not just people with type O blood.
These results are not surprising, given that there was little scientific basis for D’Adamo’s claims in the first place. The human population is simply not divided up into agricultural type As, nomadic type Bs and hunter-gatherer type Os. Considering that the ABO blood types are present in non-human primates, they probably came on the scene at least 20 million years ago, far before humans existed, let alone were divided by cultural behaviors.
Besides, if we’re talking about blood types, the ABO system is only one of over thirty different blood type systems. The ABO system is certainly the most well known, but you’d be in just as much trouble getting a transfusion from someone who’s incompatible for any of the other matching systems.

Jingzhou Wang, Bibiana García-Bailo, Daiva E. Nielsen, & Ahmed El-Sohemy (2014). ABO Genotype, ‘Blood-Type’ Diet and Cardiometabolic Risk Factors PLoS ONE DOI: 10.1371/journal.pone.0084749.

Thursday, January 30, 2014

Sea anemones—not just for the tropics

If you think NASA loves acronyms, get a load of the multi-national ANtarctic geological DRILLing (ANDRILL) program’s Submersible Capable of under-Ice Navigation and Imaging (SCINI). Researchers in Antarctica sent the submersible through drill holes in the 250 meter thick Ross Ice Shelf to see what was underneath. You won’t believe what they found. A brand new species of sea anemone. 

A. Close up of Edwardsiella andrillae B. Field of specimens. Red dots are 10 centimeters apart
C. Single specimen.
This was even more surprising because the expedition scientists were just planning to take ice samples, they did not expect to find any life under the ice and certainly not sea anemones. The researchers had to do some hasty improvising to examine and collect the anemone samples.

Members of an Antarctic drilling team, from left: Bob Zook, Paul Mahecek and Dustin Carroll, hold the underwater robot that was used to discover the sea anemone. (Frank Rack, CBC News)

These sea anemones (Edwardsiella andrillae) actually burrow into the ice, dangling down into the frigid water below. They range in size from seven centimeters when fully extended to two centimeters when retracted into the ice. Although that sounds tiny, it’s actually quite large by burrowing anemone standards.
The fact that the researchers found fields of the anemones at two different drill sites (A and B below) strongly suggests that the creatures are extremely abundant under the ice. Marymegan Daly of The Ohio State University and Frank Rack and Robert Zook from the University of Nebraska-Lincoln found thousands of these hardy specimens.
Drill sites A and B are roughly 6 kilometers apart.

Daly M, Rack F, & Zook R (2013). Edwardsiella andrillae, a New Species of Sea Anemone from Antarctic Ice. PloS one, 8 (12) PMID: 24349517.

Wednesday, January 29, 2014

Just for fun: Skeleton shrimp

Meet Liropus minusculus, a new species of skeleton shrimp found off the coast of California.

You may be interested to note that this creature is neither a skeleton nor a shrimp. Instead, it's a crustacean in the Caprillidae family of amphipods

Weird doesn't begin to describe these creatures. Check out this clip:

For much more on this, including a Caprillidae anatomy lesson "skeleton shrimp have taken the basic amphipod body plan and dialed all the features to 'scary'"head over to Jennifer Frazer's piece at Scientific American Blogs.

Tuesday, January 28, 2014

A new way to analyze precious works of art

This is what happens when elderly parishioners take it upon themselves to restore artwork. This was a 19th century fresco by Spanish painter Elias Garcia Martinez in the Santuario de Misericodia church in Borja, northeastern Spain.
In order to preserve and restore art work, you need to understand exactly what materials and techniques the original artist used. For example, you can create nearly the same shade of purple by either applying a thin red glaze on top of blue pigment or by mixing blue and red pigments together first. If you don’t know which pigments and methods the artist the used, you could easily botch up your restoration efforts.
Unfortunately, conventional imaging can’t penetrate very deeply into paint layers and don’t offer 3D molecular information, whereas methods that can give that kind of information require the removal of physical samples. But no longer.  Tana Villafana of Duke University and her colleagues have used pump-probe microscopy to create 3D molecular maps of paintings.

The technique was originally used to visualize organic pigments in biological samples as a way to screen for skin cancer. Briefly, you use a series of short pulses of light to electrically excite (pump) the sample and then another series of pulses to detect (probe) that change. 
The tricky part is finding the proper wavelengths to pump through the apparatus to give you the information you need. Skin pigments are much less variable than the range of materials used to color paintings, and perhaps more importantly, they aren’t combined in myriad ways. However, the scientists were successful in making a nondestructive 3D image of an intact 14th century painting (The Crucifixion by Puccio Capanna).
Left: a femtosecond pump-probe microscope positioned over a section of The Crucifixion by Puccio Capanna.
Top right: a false-color face-on view of the section, showing blue lapis lazuli fragments.
Bottom right: a 60-µm-thick cross-section of the painting, revealing the thickness of the pigment.
PNAS PMID: 24449855.

The authors believe this technique can be used not only to completely deconstruct paintings so that they can be properly restored, but to more fully understand the degradation of pigments so that artwork can be better protected and preserved.

Villafana TE, Brown WP, Delaney JK, Palmer M, Warren WS, & Fischer MC (2014). Femtosecond pump-probe microscopy generates virtual cross-sections in historic artwork. Proceedings of the National Academy of Sciences of the United States of America PMID: 24449855

Monday, January 27, 2014

To stigmatize or not to stigmatize obesity

There’s no doubt that obesity is a problem in the U.S. But what’s the best way to stop the epidemic of excessive weight gain? Perhaps it would be helpful to stigmatize obesity by discriminating against the overweight and by publicly pointing out their short failings. If you think that, you’re in for a ruder awakening than the people this method was tried on. Negative talk about overeating makes women who perceive themselves as overweight less able to control their eating.
Researchers led by Brenda Major from the University of California, Santa Barbara recruited 93 female students, 49 of whom rated themselves as overweight. Among the 91 women who consented to be measured, 32 had BMI’s indicating that they were in fact overweight.
The participants were asked not to eat for two hours prior to the study. They didn’t know the study had anything to do with food or weight, instead they were told the study was about physiological responses and communication. Let that be a lesson to anyone participating in a  sociology or psychology study. It’s never about what they say it’s about.
The subjects were asked to read an, unbeknownst to them, fake New York Times article. After reading the article, they gave a videotaped five minute presentation, discussing the article and explaining its implications. Half the people got an article called “Lose Weight or Lose Your Job”, the other half were given the nearly identical article “Quit Smoking or Lose Your Job”. Once they were done with their presentations, it was break time in a room conveniently equipped with bowls of pre-measured snacks.
As you can see from the following chart, women who were forced to discuss the pitfalls of smoking (control) were able to moderate their eating behavior depending on how overweight they perceived themselves to be. That is, the more overweight women felt they were, the less they ate. In contrast, the women who had been subjected to negative weight information ate more snacks if they felt they were overweight.
Full-size image (13 K)
Control = smoking article
WS Treat = weight article
DOI: 10.1016/j.jesp.2013.11.009.
The most likely explanation is that brain power is a limited resource. We only have so much attention and energy for any task. When we’re subjected to one kind of stress, such as feeling judged, we have less energy available to fight impulses. One clue that this is what’s going on here is that perceived weight affected the women’s behavior much more than objective weight, as measured by BMI.
All this goes to show that shaming people for behaviors we’d like to discourage is counterproductive. I hope no one is surprised by that.

Brenda Major, Jeffrey M. Hunger, Debra P. Bunyan, & Carol T. Miller (2014). The ironic effects of weight stigma Journal of Experimental Social Psychology, 51, 74-80 DOI: 10.1016/j.jesp.2013.11.009.

Friday, January 24, 2014

Another difference between liberals and conservatives

It’s normal for people’s eyes to dilate slightly while they’re thinking. But we don’t always dilate the same way. Depending on our biases, our eyes can behave slightly differently. University of Amsterdam researchers Jan Willen de Gee, Tomas Knapen and Tobias Donner found that conservatives and liberals showed different dilation patterns.
The scientists measured pupil size at constant luminance in participants while they strained to detect a faint pattern above random noise. For each trial, the subjects had to indicate whether or not the pattern was present by pressing a ‘yes’ or ‘no’ button. The images were calibrated for each subject’s eyesight so that the subjects were correct about 75% of the time.  Most trails took less than three seconds, with ‘no’ choices taking longer than ‘yes’ choices, and incorrect answers taking longer than correct ones.
Everyone’s eyes dilated while they were thinking. No surprise there. However, people who identified as conservative showed a much greater difference in dilation between ‘yes’ choices and ‘no’ choices. For self-identified liberals, yes or no, right or wrong, they always dilated about the same amount. Not so for the conservatives, who had little dilation when choosing ‘no’, but lots of dilation when choosing ‘yes’ regardless of whether they were right or wrong in making that choice.

The authors speculate that conservatives find saying ‘yes’ about something more effortful than liberals do. No comment.

de Gee JW, Knapen T, & Donner TH (2014). Decision-related pupil dilation reflects upcoming choice and individual bias. Proceedings of the National Academy of Sciences of the United States of America PMID: 24449874.

Thursday, January 23, 2014

3D printing the universe

When it comes to enjoying the wonders brought to us by the Hubble Space Telescope, blind people are really missing out. There's not much that can be done about that. Or is there? 

Carol Christian and Antonella Nota of the Space Telescope Institute have been recreating Hubble images using 3D printers. Not only are they trying to convey size and distance, but brightness as well, which requires a great deal of ingenuity. The astronomers and a team of software designers began incorporating tactile features such as heights and open circles to represent elements like dust and gas.

These images show people with visual impairments using their fingers to explore 3-D tactile representations of images taken by NASA's Hubble Space Telescope. In these representations, stars, filaments, gas, and dust shown in Hubble images of the bright star cluster NGC 602 have been transformed through 3-D printing into textures, appearing as raised open circles, lines, and dots in the 3-D printout. These features also have different heights to correspond with their brightnesses. The tallest, and therefore brightest, features are a tight group of open circles, which represent the stars in the core of the cluster. 

Credit: NASA, ESA, and M. Estacion (STScI).

While no one can claim that a blind person's experience with the plastic 3D printouts will approach that of a sighted person viewing a Hubble image, so far the test audience seems to be pleased. One hundred visually impaired people were not only able to enjoy the prototypes, but were able to identify astronomical features within them.

More from Science Daily.

Wednesday, January 22, 2014

Just for fun: Graphic drawings

I can't stop staring at graphic artist Alex Konahin's weird and intricate drawings of anatomy

and insects:
New Ornate Insects Drawn by Alex Konahin insects illustration drawing

More on tumblr and Facebook. Do yourself a favor and check them out.

Tuesday, January 21, 2014

Triggering drug release with light

Some illnesses are best treated by the periodic release of drugs into the patient’s bloodstream. Take diabetes, for example. A patient can’t just take his yearly supply of insulin all at once, treating the disease is a continuous and ongoing process.

This leads to two problems. First, depending on the illness, it can be complicated, expensive and/or invasive to monitor and maintain the right dosage of medicine coursing through a patient’s body. And second, the patients themselves have to be compliant, not purposefully or accidentally skipping doses.

But what if you could eliminate both problems by implanting a remotely controlled device to release the medicine that was triggered by light? 

Researchers led by Brian Timko of Harvard Medical School and MIT have developed a gold nanoparticle membrane that becomes porous only when irradiated with near infra-red light. Light at the right wavelengths causes the network of polymers in the membrane to collapse. After the light source is removed, the membrane reforms. If you enclose medicine within these membranes, you have a device that will release those drugs when you expose it to light.

Diabetic rats were implanted with devices containing a synthetic form insulin. The devices were triggered either by exposure to light or by immersing the rats in a very hot bath. As hoped, insulin was released into the rats’ bodies from the now permeable membranes. The devices could be retriggered every day for at least five days, continuing to release more medicine.

Obviously, this is in the ‘proof of concept’ stage. No one is going to say, “it’s too arduous to remember to take my pills, so instead I’ll have them implanted and stand under a special light four times a day.” It’s not even clear to me who would be responsible for doing the triggering, the doctors or the patients themselves. Nevertheless, this technique does have tremendous potential, especially for patients who require long-term medication.

Brian P. Timko, Manuel Arruebo, Sahadev A. Shankarappa, Brian McAlvin, & et al (2013). Near-infrared–actuated devices for remotely controlled drug delivery Proceedings of the National Academy of Sciences of the United States of America : doi/10.1073/pnas.1322651111.

Monday, January 20, 2014

What’s the score on readability formulas?

School children are usually given reading assignments geared to their grade level. At least, that’s the idea. The trouble is, according to John Begeny and Diana Greene from North Carolina State University, our current methods of evaluating the ‘readability’ of texts may be seriously flawed.

A number of factors go into determining the difficulty level of reading material. The percentages of ‘easy’ words (with which kids at a particular grade level are likely to be familiar), the percentage of multisyllabic words and the average number of words per sentence all go into mathematical formulas to compute readability. Not surprisingly, the different formulas don’t all agree on the readability score of specific texts. The bigger question is whether any of them can give an accurate picture of how challenging a piece of literature is.

The authors recruited 360 students in second through fifth grade for their study. Each child was asked to read six short passages aloud, two of which were supposedly below his grade level, two at grade level and two above grade level. Oral reading ability was measured as the number of words read correctly in one minute. 

Of the eight different readability scales the authors used, most were unable to either predict actual reading difficulty or accurately discriminate between grade levels. For example, the kids didn’t necessarily find the 4th grade passages more challenging than the 3rd grade passages. 
The most successful formula in this regard was one called Dale-Chall, and even it only had a 79% track record. At best, the other seven formulas were valid for a single grade level rather than for all four tested grade levels. All the formulas were more accurate for above average readers than for below average readers, which is, of course, the demographic most in need of reading instruction. 

Where does this leave the teacher trying to either assess a student’s reading ability or select appropriately challenging reading material for her class? A teacher in this position might do better trying a few literature passages and seeing what works rather than relying on readability scores. 

John Begeny, & Diana Greene (2014). CAN READABILITY FORMULAS BE USED TO SUCCESSFULLY GAUGE DIFFICULTY OF READING MATERIALS? Psychology in the Schools, 51 (2) DOI: 10.1002/pits.21740

Friday, January 17, 2014

Confronting word blindness

File:US Army 51636 Teddy Bear Picnic.jpg

Loyola University researchers Jason Cuomo, Murray Flaster and José Biller chronicle the story of a forty year old woman they call M.P. who suffered a sudden onset of ‘word blindness’ following a stroke. This was particularly galling for the kindergarten reading specialist, who’s life mission had been to read to children and to help them learn to read. Thanks to her hard work, M.P. found a way to decipher one word at a time.

Word blindness, or alexia without agraphia is a condition that robs patients of the ability to read. Bizarrely, these people can still write. They can also speak and understand spoken language, they just can’t make out written words. In order to succumb to this syndrome, you’d need to suffer lesions that specifically disrupt visual inputs to the left angular gyrus (the ‘language’ zone), a fortunately rare event. This was most likely the case with M.P., though her biopsies were negative. In any case, M.P. could no longer read or tell time.
M.P. wasn’t about to let things stand as they were and began using all the tools in her arsenal to regain her ability to read. When the normal techniques M.P. was proficient in using to help her young students proved to be totally ineffective, she invented a different tactic. She capitalized on the fact that although she couldn’t recognize letters by sight, she could identify them by their feel. Thus, she traces over each individual letter with her finger until she can piece together the word. 

The authors give the following example of this effective, though arduous technique.
Given a word, M.P. will direct her attention to the first letter, which she is unable to recognize. She will then place her finger on the letter and begin to trace each letter of the alphabet over it in order until she recognizes that she has traced the letter she is looking at. “That is the letter M,” she declares, after tracing the previous 12 letters of the alphabet with her finger while deciphering a word in front of her. Three letters later, she is able to shorten this exercise with a guess: “This word is ‘mother,’” she announces proudly.

Needless to say, this method is far too laborious for pleasure reading, let alone reading to children, which M.P. sorely misses. She’s had to give up her job as a kindergarten teacher and take another job, though she still volunteers her time in her community. It’s been a little over a year since her stroke, and it doesn’t look like her deficit will ever be overcome. Still, thanks to her perseverance, she can at least make out words when she really needs to. 

Jason Cuomo, Murray Flaster, & José Biller (2014). Right Brain: A reading specialist with alexia without agraphia Neurology, 82 (1) : doi: 10.1212/01.wnl.0000438218.39061.93.

Thursday, January 16, 2014

Are spiders omnivores?

Western spotted orbweaver (Neoscona oaxacensis).

When you think of mealtime for a spider, what comes to mind? Flies? Beetles? Aphids? How about pollen? According to Benjamin Eggs and Dirk Sanders of the University of Bern, pollen could make up a quarter of the diet of orb-weaving spiders.

Orb-weaving spiders (Araneidae) not only spin webs, but they also dismantle and eat those webs at regular intervals. Very often the sticky silk threads are covered with pollen, which the spider ingests along with the web. Aha! you say, the spider isn’t eating the pollen on purpose so it doesn’t count. That might be true except for one thing.

Most pollen grains are too large for spiders to eat. I know that’s hard to believe, but spiders have really tiny mouth parts. In order to consume hard objects like pollen, they have to first dissolve the outer coating and then slurp up the insides, just like they do with insects. In other words, they have to want to eat the pollen.

And sure enough, they do want to eat pollen. Chemical tests showed that wild caught spiders consume both flying insects and pollen in a ratio of three to one. That’s a lot of pollen.

To find out what the benefit could be of eating all that pollen, the researchers compared two groups of captive spiders. Group A were fed fruit flies three times a week. Group B got the flies but also had their webs dusted with birch pollen. While group B spiders definitely ate both pollen and flies, they didn’t grow any larger or faster than group A spiders who only got flies.

So why do spiders purposefully chow down on pollen if it doesn’t help them grow? One possibility is that pollen does help wild spiders who aren't getting fruit flies delivered to them at regular intervals. When flying insects are scarce or wily, pollen may mean the difference between starvation and survival. The researchers suspect that pollen is a particularly important supplement for young spiders. 

For whatever reason, the spiders clearly are consuming pollen, and in large quantities. Other animals with diets that are one quarter vegetable are considered omnivores, therefore, spiders should be reclassified as omnivores. 

Eggs B, & Sanders D (2013). Herbivory in spiders: the importance of pollen for orb-weavers. PloS one, 8 (11) PMID: 24312430.