Monday afternoon one more time as scheduled. Science talk returns to brighten your day with selections from science sites across the globe. New discoveries, new takes on old knowledge, and other bits of news are all available for the perusing in today's information world. Today's tidbits include why do we recoil at unpleasant noises, the trigger for explosive volcanic eruptions, quantum effects observed in cold chemistry, engineered flies spill the secret of febrile seizures, seaweed as an alternative protein source, and Cambrian fossil pushes back the evolution of complex brains.
Pull up that comfy chair and grab a spot on the porch. There is always plenty of room for everyone. Another session of Dr. Possum's science education, entertainment, and potluck discussion is set to begin.
Featured Stories
Most all of us have had the experience of recoiling from an unpleasant noise such as the scratching of nails on a chalkboard.
Brain imaging has shown that when we hear an unpleasant noise the amygdala modulates the response of the auditory cortex heightening activity and provoking our negative reaction.
...
Researchers found that the activity of the amygdala and the auditory cortex varied in direct relation to the ratings of perceived unpleasantness given by the subjects. The emotional part of the brain, the amygdala, in effect takes charge and modulates the activity of the auditory part of the brain so that our perception of a highly unpleasant sound, such as a knife on a bottle, is heightened as compared to a soothing sound, such as bubbling water.
Analysis of the acoustic features of the sounds found that anything in the frequency range of around 2,000 to 5,000 Hz was found to be unpleasant.
Studies of eruptions continue as scientists report finding the
trigger for explosive volcanic eruption.
The Las Cañadas volcanic caldera on Tenerife, in the Canary Islands, has generated at least eight major eruptions during the last 700,000 years. These catastrophic events have resulted in eruption columns of over 25km high and expelled widespread pyroclastic material over 130km. By comparison, even the smallest of these eruptions expelled over 25 times more material than the 2010 eruption of Eyjafjallajökull, Iceland.
By analysing crystal cumulate nodules (igneous rocks formed by the accumulation of crystals in magma) discovered in pyroclastic deposits of major eruptions, the scientists found that pre-eruptive mixing within the magma chamber – where older cooler magma mixed with younger hotter magma – appears to be the repeating trigger in large-scale eruptions.
Very cold temperatures are known to effect reactions of many sorts.
At very low temperatures, close to absolute zero, chemical reactions may proceed at a much higher rate than classical chemistry says they should – because in this extreme chill, quantum effects enter the picture. A Weizmann Institute team has now confirmed this experimentally; their results would not only provide insight into processes in the intriguing quantum world in which particles act as waves, it might explain how chemical reactions occur in the vast frigid regions of interstellar space.
Long-standing predictions are that quantum effects should allow the formation of a transient bond – one that will force colliding atoms and molecules to orbit each other, instead of separating after the collision. Such a state would be very important, as orbiting atoms and molecules could have multiple chances to interact chemically. In this theory, a reaction that would seem to have a very low probability of occurring would proceed very rapidly at certain energies.
In my branch of veterinary medicine seizures are a large part of practice. News that scientists have found
the secret to some forms of seizure is very exciting indeed.
The researchers used a technique called homologous recombination — a more precise and sophisticated technique than transgenic gene engineering — to give flies a disease-causing mutation that is a direct analogue of the mutation that leads to febrile epileptic seizures in humans. They observed the temperature-dependent seizures in whole flies and also observed the process in their brains. What they discovered is that the mutation leads to a breakdown in the ability of certain cells that normally inhibit brain overactivity to properly regulate their electrochemical behavior.
Now for someone to bring this to practical application with drugs or genetic modification of a different sort as these seizures are important in humans.
In the ever widening search for alternative food sources scientists are evaluating seaweed as a protein source.
Teagasc researchers are looking to seaweed for proteins with health benefits for use as functional foods. Historically, edible seaweeds were consumed by coastal communities across the world and today seaweed is a habitual diet in many countries, particularly in Asia. Indeed, whole seaweeds have been successfully added to foods in recent times, ranging from sausages and cheese to pizza bases and frozen-meat products.
Researchers have previously shown that protein-rich red seaweeds such as Palmaria palmata (common name Dulse) and Porphyra (common name Sleabhac or Laver) species may potentially be used in the development of low-cost, highly nutritive diets that may compete with current protein crop sources such as soya bean. For example, the protein content of Dulse varies from between 9-25% depending on the season of collection and harvesting. The highest percentage protein per gram of dried whole seaweed is normally found in P. palmata collected during the winter season (October – January). Valuable amino acids such as leucine, valine and methionine are well represented in Dulse. In Porphyra species, the amino acid profile is similar to those reported for leguminous plants such as peas or beans.
A well preserved fossil of an
extinct arthropod with a complex brain shows development earlier than thought.
Embedded in mudstones deposited during the Cambrian period 520 million years ago in what today is the Yunnan Province in China, the approximately 3-inch-long fossil, which belongs to the species Fuxianhuia protensa, represents an extinct lineage of arthropods combining an advanced brain anatomy with a primitive body plan.
The fossil provides a “missing link” that sheds light on the evolutionary history of arthropods, the taxonomic group that comprises crustaceans, arachnids and insects.
The researchers call their find “a transformative discovery” that could resolve a long-standing debate about how and when complex brains evolved.
Knucklehead's Photo of the Week
Acropora Jungle
©Knucklehead, all rights reserved, presented by permission. (Click on the image to see more in the same series.)
Other Worthy Stories of the Week
New Exoplanet is twice Earth's size and made mostly of diamond
Spider silk could weave biodegradable computer chips
Wired Science space photo of the day: Star formation in Berkely 87
X-raying stellar winds in a high speed collision
When galaxies eat galaxies they get denser
Reason discovered for the toxicity of indoor mold
Researchers create 'nanoflowers' for energy storage, solar cells
Physicists extend special relativity beyond the speed of light
Large water reservoirs at the dawn of stellar birth
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NASA picture of the day. For more see the NASA image gallery or the Astronomy Picture of the Day Archive
Helix Nebula, NASA, Public Domain
