Learn node: Meerkat facts, play and scorpion dismemberment

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Posted on 16th November 2007 by Judy Breck in animals | biology | environment

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meerkat rock alertThis learn node points to facts about the mammal Suricata suricatta, known as the meerkat, that are set out with excellent images (including the one to the right) in the Animals pages of Utah’s Hogel Zoo website. There are more facts at the Meerkat Information page of a zoological park that cares for meerkats who need a home. An article in the magazine of the American Museum of Natural History, Natural Science, by Lynda L. Sharpe is an expert description of some of what is known about the animal’s behavior: Meerkats At Play: Evolution demands that activities costing a lot of energy provide survival value in return. But what do these rambunctious little mammals gain from having so much fun?

Meerkats have their learning duties as well as frequent recess. A Live Science report (with amazing pictures) describes: Hunting 101: Meerkats Teach Scorpion Dismemberment in which a seventy-day-old pup learns how to eat a scorpion fed to it live. Only the not squeamish click here.

Within the webpages mentioned are links to more sources chosen by the page authors. Like their burrows, the online network about meerkats is complex and connects among various chambers of information.

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Learn node: History of chocolate may begin with cacao beer

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Posted on 13th November 2007 by Judy Breck in history | sciences

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chocolate history cocoa

This tasty learn node includes reports of discoveries in the history of chocolate from the Los Angeles Times, New York Science Times and other open sources relaying to the public science news that is from a source is limited to its paid subscribers (in this case the Proceedings of the National Academy of Sciences).

The chocolate news from the LA Times report:

Humans began exploiting cacao beans for alcohol before they started using them to make chocolate, according to new findings that push the earliest known use of cacao back about 500 years.

Residue scraped from pottery vessels dating to 1400 B.C. to 1100 B.C. indicate that residents of Honduras’ remote Ulua Valley fermented the sweet pulp of the chocolate plant to make an alcoholic drink well before they began grinding the bitter seeds and mixing them with honey and chiles to produce the equivalent of modern cocoa. . . .

Open chocolate history, chemistry and food information are richly available online. To pick a few pieces out of the virtual chocolate knowledge box: This MIT Kitchen Chemistry page includes a topic-by-topic online chocolate topic tour. Chicago’s Field Museum has an online chocolate knowledge feast Chocolate: The Exhibition. And the US Food and Drug Administration has a page (from which the image of chocolates above is taken) on its standards for chocolate.

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Learn node: Brainbows add color to neuron viewing

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Posted on 6th November 2007 by Judy Breck in biology

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brainbow neuronsThe image in this learn node of mouse neurons of many colors is from a Harvard Science video called Somewhere, inside the Brainbow which you can view by clicking its title in this sentence. The accompanying HARVARDSCIENCE article here overviews the project, which is led by Harvard’s Jean Livet, Joshua R. Sanes, and Jeff W. Lichtman. The article explains:

By activating multiple fluorescent proteins in neurons, neuroscientists at Harvard University are imaging the brain and nervous system as never before, rendering their cells in a riotous spray of colors dubbed a “Brainbow.” . . .

“There are few tools neuroscientists can use to tease out the wiring diagram of the nervous system; Brainbow should help us much better map out the brain and nervous system’s complex tangle of neurons,” Lichtman said.

Equal parts pointillism, fauvism, and abstract expressionism, the resulting images could also help scientists identify how brain wiring goes awry in many different diseases. Brainbow could also help track the complicated development of the mammalian nervous system, currently understood only in general terms. This, in turn, could elucidate the origins of the many brain disorders that arise early in development.

Drawing upon a mix of genetic tricks and special proteins that cause cells to glow, Brainbow uses a well-known genetic recombination system known as Cre/lox in a new way, to shuffle genes encoding green, yellow, orange, and red fluorescent proteins. The researchers painstakingly assembled the Brainbow transgene from snippets of DNA, and inserted it into neuronal DNA. As they predicted, the cut-and-paste recombination occurred totally at random, in the process assigning scores of different colors to neurons. This variation makes neurons leap out from one another visually under ordinary confocal microscopy.

Photonics.com picked up on the Brainbow story from the scientific imaging perspective, with an article called ‘Neurons Glow in ‘Brainbow’: “Brainbow allows researchers to tag neurons with roughly 90 distinct colors, a huge leap over the mere handful of shades possible with current fluorescent labeling. By permitting visual resolution of individual brightly colored neurons, this increase should greatly help scientists in charting the circuitry of the brain and nervous system.”

Chemistry World calls its report on this research Brain’s wiring seen in Technicolor, and includes nine still images of different Brainbow perspectives.

If you visit the the Brainbow links above, and others such as a report today in the New York Science Times, you will note that they all mention that Brainbow is the cover story of this week’s Nature magazine. The report in Nature magazine is not, however, a learnode (a node for learning in the open Internet) because it is not open. All of the other sources mentioned, and the supplementary links that they offer are open. What makes Nature not open is more than the fact that it is closed except to paid subscribers and purchasers of its Brainbow article. The Nature article is also not open because it cannot be a node in a network cluster of Brainbow links. Only open links can be learnodes in subject clusters where the links enrich each other and keep each other up-to-date. By analogy to the neuron image above: the open articles interconnect like the different colored neurons do; the Nature article is an isolated dot with no extending dendrite.
GOTO more biology learn node clusters.

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