Bacteria that talk to each other

Bonnie Bassler, who teaches molecular biology at Princeton, explains that bacteria don't just grow and divide, grow and divide. They speak to each other and with other species of bacteria through their chemicals. Bassler studies how bacteria use chemical signals to act as coordinated social units. In this delightful TED talk, Bassler discusses how her research group has studied the manner in which bacteria talk to each other. They make chemical "words" to enable group activities (such as triggering the timing for effective virulence attacks), sensing each other through their "quorum-sensing molecules." They can also sense the difference between themselves and other bacteria. Note that each of us is 99% bacterial. Our human body consists of about one trillion of "our own" cells, but ten trillion bacteria. We have about 30,000 of "our own" genes, but we carry about 100 times more bacterial DNA than human DNA. Bacteria live as "mutualists" with us. They help us digest our food, make our vitamins, protects us from other pathogens and help us survive in numerous other ways. Rather than using antibiotics to kill bacteria (which inevitably selects for more virulent strains), Bassler suggests that a better understanding of the communications schemes used by bacteria is allowing scientists to develop potent new medicines. This is an upbeat and informative talk regarding a most ancient form of life.

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What it means (and doesn’t mean) to be “open minded.”

What does it mean to be "open minded?" This excellent video gets right to it. Simple, straight-forward reasoning with entertaining animation. I've never seen this topic better-discussed. The video is by Doug, "Qualiasoup," who puts this quote on his youtube site:

"It is not acceptable to have a religion where the alternative to faith is punishment — that's how you train dogs, not develop people." - Deng Ming-Dao Consider some of his additional videos, such as this one on the basics of evolution.

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MrTitanium with a Lead Pipe on the Patio

If the title didn't give you a Clue, then I just have to tell you that I like metals. I like melting metals. And I finally did a video of metal melting. Why? People are always asking me about how light titanium metal is. I was inspired by Theodore Gray and his Periodic Table Table to collect a set of samples of representative metal bars so as to show people. To let them feel for themselves. I started with Tungsten, because it is as heavy as gold and the hardest one to shape. I then collected and shaped matching bars of aluminum, titanium, bronze (95% copper), steel (97% iron), and magnesium (lighter than carbon). But absent the lead, I can't illustrate how much heavier tungsten (gold and platinum) are than lead. Pity I don't dare use silver, gold, or platinum bars. They would be funexemplars, but I fear short lived. But lead (Pb from the Latin Plumbum, as in plumbing, plumb-bob, etc) is now harder to get. This useful material has been in household use for almost 6,000 years. Children who likely drank from lead vessels gave us every advance in our civilization. But about a generation ago, it was declared toxic. So now it is getting hard to find outside of radiation labs, and expensive there. So, I decided to cast my own piece of fresh lead plate from some crusty and oxidized 19th century lead pipe. To feel the pipe is to understand its utility as a weapon; heavy and rigid, yet soft. Unfortunately, I didn't set up my camera to show me chopping up the lead pipe. I used a hammer and chisel to get through the crustiest parts (hundred year old drain pipe, eww). But tin snips work well on 1/4" thick lead. It cuts like cold butter. But shiny. And the piece I ended up with evoked a geological feature I'd visited: Shiprock in New Mexico. Magma oozed up through a crack in the Earth's crust forming a vane much like you see on my cast plate. An accidental demonstration in practical geology.

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