Today is Friday the 13th. Neil deGrasse Tyson tweeted: "Remember that Thursday the 12ths are just as rare as friday the 13th!
Science at Atheist Universe
VIDEO THE WEEK: Giant Japanese hornets slaughter European honeybee hive. From National Geographic. Not for the faint of heart. Hat tip to Doone.
Many more fabulous nature videos at the AVM Video Thread
EVOLUTION: Evolution is written in primates’ faces. Primates have the most astounding diversity of faces of any mammalian lineage, with an incredible gamut of coloration, facial ornamentations, etc. This rich diversity has puzzled zoologists for a long time. The faces took at least 24 million years to evolve. A recent publication reporting an investigation of the faces of 129 primate species from central and South America, links facial diversity, more specifically pigmentation and pattern of coloration, with adaptation to different environments, but mostly, to type of social structure. The researchers investigated environmental factors such exposure to the sun, and confirmed that some aspects of facial coloring was affected by ecology, and in colder areas facial hair was found to be longer. But the biggest effect was the adaptation to living in small groups vs large groups. It appears that facial patterns function in communication and species recognition. Species living in smaller groups and close to a whole bunch of related species have evolved more complex coloration patterns, and hair ornamentations, while primates who live in large groups evolved increasingly plain faces to aid inter-species communication by way of facial expressions. If you are highly social, expressions count more than facial patterns, and very bright colors or distinct patterns may interfere with communication through facial expressions. Remarkably, humans have the plainest faces of all primates.
ZOOLOGY: The scorpion's giant eye. Scorpions already have a superabundance of eyes, sometimes as many as 12, but according to a recent publication, they may actually be all eyes. Their exoskeleton can act as a giant proto-eye, his whole surface may actually be one giant photoreceptor that can detect shadows and moonlight. Scientists have puzzled at the scorpions ability to find a blade of grass or other refuge to scurry under, even in total darkness. They devised an experiment covering the scorpions’ eyes to see their reactions to different wavelengths, in the visible and the UV range. The scorpions with covered eyes moved in response to UV light but not visible light. This property may explain why scorpions fluoresce to UV light. The researchers hypothesized that their cuticle as a giant photo-receptor that converts UV light to green light (scorpions are most reactive to green light) ad then relaying the information to the animal's central nervous system. In order to confirm this, scientists need to block the cuticle's ability to receive UV light, but unfortunately sunscreen kills the poor creatures.
Octopuses Rewrite Their RNA to Beat the Cold. Another great story on the complexity of life and the astonishing capabilities of animals to adapt to their environments. I also love this story because it involves RNA editing, one of the lesser known cellular regulatory mechanisms, and not mutations in genes (in other words, in the organism's DNA), which is the first thing that pops to mind when thinking about adaptation or evolution. During RNA editing, the nucleotide sequence of the RNA, synthesized from the gene, gets altered. The gene does not change. But the sequence of amino acids in the protein coded by the RNA changes, and with it, the protein's function. Ion channels, which are proteins that allow ions to flow in and out of the cell membrane, are fundamental in the firing of neurons. Frigid temperatures slow down the opening and closing of these channels, and thus the ion channels in the neurons of animals that live in the cold, especially cold blooded animals, are different in sequence so that they can function faster in very low temperatures. However, when potassium channels from two different species of octopus, one tropical, living in Puerto Rico, and another one Antarctic were expressed in the lab, they made identical proteins! But when they isolated the proteins from wild octopuses, they had different sequences. The secret was RNA editing. The Antarctic octopus edited the RNA at 9 sites, one of which being crucial for adaptation to the cold, since that one change alone doubled the potassium channel's closing speed. I'm sure now many other scientists will start looking for RNA editing to explain other adaptations. It's fascinating stuff.
NEUROSCIENCE: How the human brain sees faces. We often make fun (and rightly so) at the pareidolia phenomenon when it happens to Christians spotting Jesus's face on an old sock or the Virgin Mary's face on a piece of toast. The fact remains that our brains are really good at spotting faces and this is why we see them in inanimate objects. Naturally, most normal people can immediately tell that it is not a real human face staring back at us. But how does our brain decide what is a real human face and what only looks like a human face? We know that the fusiform gyrus (part of the temporal lobe, towards the bottom of the brain) is involved in face and body recognition (and also in the processing of color information and word recognition). But how does it sort out real from not real? Neuroscientists did an experiment using photos of real faces and photos of faces ion rocks, etc., that machines mistakenly label as human faces, and measured brain activity of volunteers looking at the pictures by fMRI. They found different activity patterns in the right and left side of the brain. The left side would flare with activity whether the face was real or just an eerie rock formation, but the right side of the fusiform gyrus had a very different activation pattern whether the face was real or whether it was something that only resembled a face. The researchers conclude that the left side does its job face in ranking something as a face-like image, transmits the information to the right side, and the right side makes the distinction between a real human face and something that only looks like it, however eerily similar it may be to a face. This clear distinction of function is one of the first known examples of the left and right side having different roles in high-order visual processing tasks.
ASTROPHYSICS: Evidence of multiverses colliding? Famous astrophysicist Stephen Hawking is a big proponent of M-theory (a type of string theory) as the best current “theory of everything” in physics, One prediction of M-theory is that there are multiple universes, with different values for the physical constants, which is why our universe seems so “finely tuned” to specific values that make life possible. But is M-theory testable or even falsifiable? One way of testing it is to study the cosmic microwave background radiation (CMB) to look for perturbations or signs that other universes have collided with ours in the extremely distant past. The CMB radiation has circular patterns that have led theoretical physicist Roger Penrose to propose that the Big Bang was not the beginning of space and rime, but that our universes goes through multiple continuous cycles, called “aeons”. Penrose and his colleague Vahe Gorzadyn are now making the extraordinary claim that an analysis of CMB from data collected by NASA’s Wilkinson Anisotropy Probe, supports his “conformal cyclic cosmology" theory. Penrose and Gurzadyan say they have clearly identified concentric circles and that these circles allow us to look into the aeon that would have existed before the Big Bang. Julian Barbour, a professor of physics at the University of Oxford thinks that the result is still very controversial and that other researchers will undoubtedly analyze the data very critically.
Science bits and news from other sites:
Why this winter in Eastern North America is so bizarrely warm. Many of our members are from North America and we have not failed to notice, and comment, abundantly on the unusually balmy weather that we are having this winter. It’s basically like winter is not really here. There is almost no snow: snow cover is at 19 % across the US (average is 50 % in January). Many of us automatically think climate change when this happens, but is it climate change or in this particular case, a meteorological phenomenon? The immediate explanation for this freakishly warm weather is actually meteorological: an extremely unusual jet stream during the last few months. The jet stream is what defines weather in North America, basically. It is controlled by climate patterns called oscillations, in this case, the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO). These oscillations occur because of differences in sea-level pressure, and this year these differences have been dramatic: the most extreme difference ever recorded for the NAO and the second most extreme for the AO happened this past December. This positive pressure difference has drawn warm air from the southwest over the Eastern US, instead of the cold air coming from the Arctic. We had the opposite last winter, with the two most extreme negative values on record. But why are these extremes happening? Is it climate change? Dr. Jeff Masters, a meteorologist who writes the Wunderground blog, thinks that climate models are too crude at this point to make predictions on how anthropogenic climate change could be affecting the AO now. There are links between solar activity and sunspots and positive values and between arctic sea ice loss and negative values. Whether the strong positive differences seen this winter are related to sunspots is not known.
Newly discovered hormone recapitulates the effects of exercise. Exercise benefits a variety of organ systems in mammals. Researchers have discovered a new hormone in mice, termed irisin, which is produced in muscle as a response to exercise. Irisin is also produced in humans as a response to exercise: people who had gotten 10 weeks of endurance training had double the amount of irisin in their blood than those who had not. In mice, an increase of irisin blood levels lead to an increase in energy expenditure even if it was artificially injected instead of produced by exercise. This resulted in improvements in obesity and glucose homeostasis in an obese mouse model. The new hormone was named irisin, after Iris, the Greek messenger goddess Iris, because this hormone sends information to other tissues besides muscle. An increase in irisin levels turn mouse white fat into the more metabolically active brown fat, which burns more calories, and increases the body’s susceptibility to glucose. Glucose tolerance is a sign of diabetes. After 10 days of irisin injections, obese mice fed a high fat diet had shed some weight and become more sensitive to glucose, in the absence of exercise. No negative effects have been seen so far. Irisin could be therapeutic for human metabolic disease and other disorders that are improved with exercise. It has been licensed to Ember Therapeutics for possible development as a drug to help combat obesity and diabetes.
A new species of snake: Matilda’s horned viper. A very beautiful new species of bush viper, named Matilda’s Horned Viper (Atheris matildae), has recently been discovered by the Wildlife Conservation Society in a remote hilly forest fragment in the South West region of Tanzania. It is a relative of the Usambara bush viper (Atheris ceratophora) but is considerably larger. DNA analysis suggests the species have been separated by about 2.2 million years. This colorful viper is a highly range-restricted forest species, and it should be listed as “critically endangered”. The WCS warns that often when new species are discovered, there is a rush to collect and sell specimens and in this viper’s case, this could lead to the complete disappearance of the species. Therefore, although the species description has been published, the exact location where the animal was found and lives is kept secret. In addition, the WCS has initiated a small breeding program for this new species, within Tanzania. Against this background, we have initiated a small breeding program for the new viper in Tanzania. This is intended not only as ‘insurance population’ to protect the new species from overexploitation, but also to facilitate the conservation of its threatened habitat so that this unique animal can persist in the wild. We are planning to make available (gratis) the first few dozen offspring from the captive population, in order to provide the market with captive-bred specimens of the new species. The aim is to avoid collection of wild caught specimens, lower the price of the animal and encourage responsible captive breeding by keepers in the most highly demanding countries. The ultimate goal is also to raise awareness and support for an in situ community-based forest conservation program, including community support, education and forest management. Matilda’s Horned Viper will, it is hoped, be a flagship species for the initiative.
Albatrosses symbiotic grooming relationship with sunfish. For the first time, Japanese researchers have observed a flock of albatrosses cleaning parasites off an entire school of sunfish, in the Western Pacific Ocean. The ocean sunfish is the largest bony fish on the planet; it is also very strange looking, like it’s a gigantic fish head with no body. The researchers observed and documented (go to the link for more pictures) a school of 57 ocean sunfish floating up to the surface on their broad sides, seemingly courting the floating albatrosses, by following them around and swimming next to them on the surface. These ocean sunfish were teeming with a parasite called Pennella, a parasitic shrimp-like crustacean who sinks its head on the fish and feast on their blood. Albatrosses of two different species were attracted to the floating ocean sunfish and were observed having an easy meal of the parasites they plucked off the fishes’ bodies. Although the association might have been a one-time event, there have been other reports of seabirds flocking around schools of basking sunfish. This is the first time that scientists have had the opportunity to observe and record the birds actually cleaning the ocean sunfish from their parasites.
Sunflowers Inspire Better Solar Power Tech. I’m instantly attracted to novel technology that uses nature as an inspiration (biomimicry). Evolution has figured things out before we did. In this case, the pattern of sunflower florets (the small flowers at the center of the petals, which turn into seeds) is being used as an inspiration to make more space-efficient solar panels. Sunflower florets are arranged in a specific spiral fashion, a form of Fermat spiral, in which each floret is turned at ~137 degrees (the golden angle) with respect to its neighbor. Currently concentrated solar power (CSP) plants consist of many rows of mirror heliostats concentrated on a high pillar that concentrate the heat of the sun and turn it into electricity. Very few of these CSP plants exist around the world. The constraint is that they need to be huge. Now Alexander Mitsos from MIT, is looking at the sunflower floret pattern to apply it to the layout of the CSP plants. And reduce the area needed in future designs. He used a computer model to evaluate the efficiency of different heliostat layouts and to calculate the amount of light each section reflects at any given moment. They found that arranging the mirrors in a spiral-like pattern reduced the area needed by 10% without affecting efficiency. To further improve on this, his team modeled a heliostat in which each mirror was twisted 137 degrees relative to its neighbor. The results were spectacular. The sunflower-like layout required 20 % less space and was even more efficient than the best current CSP plant, PS10, situated in Andalusia (Spain).