Dr Possum: Silkhearts, Fishspeak, And The Mysteries Of Wings

(Well. Here it is. Thursday morning. The perfect time to post the weekly wisdom of Dr. Possum. Which arrived in my inbox in plenty of time, for me to post it, as every week scheduled, on Monday morning. Except I couldn’t. Post it then. On Monday morning. Because of multiple dysfunctions. Which seem to recur weekly. Oh well. Alas. As it is written. We work in the dark. We do what we can.)

New discoveries, new takes on old knowledge, and other bits of news are all available for the perusing in today’s information world. Over the fold are selections from the past week from a few of the many excellent science news sites around the world. Today’s tidbits include life goes on near hydrothermal vents even when the vent turns icy cold, worm silk as a scaffold for heart tissue, the first recordings of deep-sea fish noises, graphene can be used to distill alcohol, how wings really work, and detecting detrimental change in coral reefs. Pull up that comfy chair and grab a spot near the fireside. There is always plenty of room for everyone. Another session of Dr. Possum’s science education, entertainment, and potluck discussion is set to begin.

Hydrothermal vents deep beneath the ocean surface usually provide a very hot environment in which life proliferates.

Scientists have long known that active vents provided the heat and nutrients necessary to maintain microbes. But dormant vents – lacking a flow of hot, nutrient-rich water—were thought to be devoid of life.

Hydrothermal vents are formed on the ocean floor with the motion of tectonic plates. Where the sea floor becomes thin, the hot magma below the surface creates a fissure that spews geothermally heated water—reaching temperatures of more than 400 degrees C.

After a (geologically) brief time of actively venting into the ocean, the same sea floor spreading that brought them into being shuffles them away from the hotspot. The vents grow cold and dormant.

And new forms of life take the place in a succession of organisms.

The human heart is an amazing organ but its ability to repair damage is limited. Scientists hope to use the silk from the Tasar silkworm as a scaffold to build new tissue and aid the repair process.

In their attempt to develop a treatment for the repair of cardiac tissue, scientists are pursuing the aim of growing replacement tissue in the laboratory, which could then be used to produce replacement patches for the repair of damaged cardiac muscle. The reconstruction of a three-dimensional structure poses a challenge here. Experiments have already been carried out with many different materials that could provide a scaffold substance for the loading of cardiac muscle cells.

As recording equipment and techniques become more affordable scientists are reaching to the depths of the ocean to record sounds from the fish living in that arena.

Unlike active acoustic studies that bounce sound waves out and back, passive acoustic studies involve just listening. (Researchers) Rountree and Juanes have been promoting underwater passive acoustic studies for more than a decade. They hope to create a census of sounds and behavior observed concomitant with sounds from many different aquatic and marine habitats.

Juanes says some fish use special “sonic muscles” to produce some sounds, and different sounds have different meanings or functions. Many are believed to be related to reproductive behavior. Some fish use a “sound map” for orientation in their immediate environment and may even use sound waves returning from distant beaches to help them navigate over longer distances. “There is a fascinating acoustic soundscape out there just waiting to be explored.”

Graphene is the thinnest and strongest material known today and is an excellent electrical and heat conductor.

Now the University of Manchester scientists have studied membranes from a chemical derivative of graphene called graphene oxide. Graphene oxide is the same graphene sheet but it is randomly covered with other molecules such as hydroxyl groups OH-. Graphene oxide sheets stack on top of each other and form a laminate.

The researchers prepared such laminates that were hundreds times thinner than a human hair but remained strong, flexible and were easy to handle.

When a metal container was sealed with such a film, even the most sensitive equipment was unable to detect air or any other gas, including helium, to leak through.

It came as a complete surprise that, when the researchers tried the same with ordinary water, they found that it evaporates without noticing the graphene seal. Water molecules diffused through the graphene-oxide membranes with such a great speed that the evaporation rate was the same independently whether the container was sealed or completely open.

Contrary to the popular belief that air moving above an airfoil must travel faster allows lower pressure from above, a new explanation for the function of wings is shown in a video.

To show that this common explanation is wrong, (researcher) Babinsky filmed pulses of smoke flowing around an aerofoil (the shape of a wing in cross-section). When the video is paused, it’s clear that the transit times above and below the wing are not equal: the air moves faster over the top surface and has already gone past the end of the wing by the time the flow below the aerofoil reaches the end of the lower surface.

“What actually causes lift is introducing a shape into the airflow, which curves the streamlines and introduces pressure changes—lower pressure on the upper surface and higher pressure on the lower surface,” clarified Babinsky, from the Department of Engineering. “This is why a flat surface like a sail is able to cause lift—here the distance on each side is the same but it is slightly curved when it is rigged and so it acts as an aerofoil. In other words, it’s the curvature that creates lift, not the distance.”

The suspicion that humans are causing damage to coral reefs began with J. Cousteau in the 1970s with evidence mounting day by day today.

Situated in shallow clear water, most coral reefs are visible to satellites that use passive remote sensing to observe Earth’s surface. But coral reefs are complex ecosystems with coincident coral species, sand, and water all reflecting light. (Researcher) Dustan found that currently orbiting satellites do not offer the spatial or spectral resolution needed to distinguish between them and specifically classify coral reef composition. So instead of attempting to classify the inherently complex coral ecosystem to monitor their health, Dustan has instead started to look for change—how overall reflectance for a geographic location varies over time.

Dustan uses a time series of Landsat data to calculate something called temporal texture¬—basically a map showing where change has occurred based on statistical analysis of reflectance information. While Dustan cannot diagnosis the type of change with temporal texture he can establish where serious changes have occurred. Coral communities have seasonal rhythms and periodicities, but larger, significant changes show up as statistical outliers in temporal texture maps and often correlate with reef decline.

Other Worthy Stories of the Week
Solar-storm-fueled auroras make for awesome backyard photography
Galaxy formation on a benchtop
Mars orbiter shows wind handiwork
Classifying solar eruptions
How viruses evolve and become deadly
Underwater caves in the Bahamas may hold clues to life beyond the Earth
Microbubbles provide a boost for biofuel production
Overgrazed grasslands tied to locust outbreaks
Carbon storage is tropical vegetation: A new map
A new clue to the chemical origins of life
First atomic X-ray laser created
Diagnostic brain tumor test could revolutionize care of low-grade glioma patients
How cholera bacteria gain a foothold in the gut
Climate-driven heat peaks may shrink wheat crops

For even more science news:
General Science Collectors:
Alpha-Galileo
BBC News Science and Environment
Eureka Science News
LiveScience
New Scientist
PhysOrg.com
SciDev.net
Science/AAAS
Science Alert
Science Centric
Science Daily
Scientific American
Space Daily

Blogs:
A Few Things Ill Considered Techie and Science News
Cantauri Dreams space exploration
Coctail Party Physics Physics with a twist.
Deep Sea News marine biology
Laelaps more vertebrate paleontology
List of Geoscience Blogs
ScienceBlogs
Space Review
Techonology Review
Tetrapod Zoology vertebrate paleontology
Science Insider
Scientific Blogging.
Space.com
Wired News
Science RSS Feed: Medworm
The Skeptics Guide to the Universe–a combination of hard science and debunking crap

NASA picture of the day. For more see the NASA image gallery or the Astronomy Picture of the Day Archive

The Earth as a Big Blue Marble, recent composite photograph, NASA, Public Domain

13 Responses to “Dr Possum: Silkhearts, Fishspeak, And The Mysteries Of Wings”


  1. 1 possum February 2, 2012 at 6:07 am

    Monday, Thursday, Tuesday. All the same in this crazy world of ours. The dysfunction of a job and outside responsibilities kept me away from these digs all week. First time with a few moments to stop in and there is science one more time. What a nice surprise. :)


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