Archive for: August, 2010

Recent Reading: 8/14/10

Aug 14 2010 Published by under Recent Reading

A few interesting bioscience-related posts elsewhere, in no particular order:

Also be sure to check out the Scientopia Cafe Press store for all your T-shirt and coffee mug needs.

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Exploding Peat Moss

Aug 13 2010 Published by under Biology & Environment

This is a cool high speed video from Science Friday of spores exploding from Sphagnum moss. It's based on the research of Williams College biologist Joan Edwards and Pomona College physicist Dwight Whitaker.

The plants generate vortex rings that ensure the spores are dispersed by air currents.

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Backyard Fauna: Western Fence Lizard

Aug 13 2010 Published by under Biology & Environment

Western Fence Lizard

Living in the 'burbs there aren't many native animals that appear in my back yard other than birds and bugs.

The exception is the Western Fence Lizard - Sceloporus occidentalis - which pretty much have the run of the place.

The lizards spend most of their time sunning themselves on walls or fences. However, occasionally they do pushups, which serves as a message to others of their kind, either as territorial challenge or part of a courtship display (I can't tell the difference, but presumably the other lizards can). You can see that behavior in this video:

Western Fence Lizards sunning themselves.

They  reduce the population of unpleasant backyard critters by eating on crickets, spiders, ticks and scorpions. They even reduce the risk of Lyme disease, because the lizards' blood carries a factor that kills the disease-causing bacteria in the gut of ticks that bite them.

I just wish our next door neighbor's cat would stop hunting them, at least on our side of the fence.

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Cooking in a Sauna?

Aug 12 2010 Published by under Food & Cooking

Ribeye steak cooked sous vide for 2 hours at ~127°F

One of the recent culinary discoveries in our household has been cooking meat sous vide.  The process is pretty simple: meat is placed in a plastic bag from which the air is removed, then the bag is sealed and submerged in a temperature-controlled hot water bath1 until the temperature of the meat is the same as the  temperature of the water.

A thick steak takes 2 hours or so to reach 125°F (51°C, rare) or 130°F (54°C, medium rare). The resulting meat is cooked evenly all the way through. Searing it for 30 seconds in a very hot pan to make it nicely brown on the outside is optional.

Salmon doesn't require as much heat as the beef. It's can be cooked nicely after 45 minutes at 120°F (49°C). Some even cook it at 116°F (47°C) or lower temperatures.3 That's not much hotter than the summer temperature in desert towns like Palm Springs, where the average high in July is 108°F (42°C).

Sauna

Bathing or cooking?

People even voluntarily expose themselves to much higher temperatures (70-80°C) in saunas. Which raises an interesting question: why don't people cook when exposed to the same temperatures so effective for cooking meat and fish?

Charles Blagden - a British physician and scientist - studied that very question in 1775. Using a room that was hot enough to boil water (236°F/113°C), Blagden made observations on the effect of heat on both his own body and a dog.

As he reported to the Royal Society4, the dog panted and held out its tongue, but the symptoms did not show evidence of "ever becoming more violent that they are usually observed in dogs after exercise in hot weather; and the animal was so little affected during the whole time, as to shew signs of pleasure whenever we approached the basket [the dog was resting in]." After an hour in the heat, a thermometer placed between the thigh and flank of the dog read 110°F - higher than a dog's normal body temperature, but significantly cooler than the room. Blagden acknowledged he had a bit of trouble taking the measurement, and he thought that what he recorded was likely higher than the dog's actual temperature.

Blangdon's demonstration that the dog's body temperature could stay cool in a hot environment was an important one. But there was the possibility that the thermometer used to measure the room's temperature was grossly inaccurate, which would invalidate his results. The obvious control experiment was to see what happened to meat placed under the same conditions.

To prove that there was no fallacy in the degree of heat shewn by the thermometer, but that the air which we breathed was capable of producing all the well-known effects of such an heat on inanimate matter, we put some eggs and a beef-steak upon a tin frame, placed near the standard thermometer, and farther distant from the cockle than from the wall of the room. In about twenty minutes the eggs were taken out, roasted quite hard; and in forty-seven minutes the steak was not only dressed, but almost dry. Another beef-steak was rather overdone in thirty-three minutes. In the evening, when the heat was still greater, we laid a third beef-steak in the same place : and as it had now been observed, that the effect of the heated air was much increased by putting it in motion, we blew upon the steak with a pair of bellows, which produced a visible change on its surface, and seemed to hasten the dressing; the greatest part of it was found pretty well done in thirteen minutes.

Thermograph of a "cold blooded" snake wrapped around a human arm.

So under conditions where a steak will quickly become well done, dogs (and humans) are able to maintain close to their normal body temperature.

As Blagdon observed, humans shed excess heat by sweating, which cools the body when it evaporates. We also flush, as blood flow increases to the skin. The fur on dogs would make sweating ineffective, but panting serves the same purpose. That ability to regulate our internal temperature is why humans - and all other mammals - are called endotherms.

Of course shedding excess heat can put an enormous strain on the body. Last fall three people died and 19 were hospitalized after a sweat lodge ceremony lead by a New Age "guru". And just last week there was a death during a sauna competition.

I say leave the high temperatures for steaks and chops, where they can do the most good.

Update 8/14: My husband pointed out that I should have included a link to this post at Sous Vide Cooking, in which a scientifically minded sous vide enthusiast  brought  a vacuum-sealed steak to a Swiss steam bath that claimed to be at 55°C (131°F) - perfect for cooking steak.  You'll have to read the post to find out how well it worked.

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1. We2 started out with the beer cooler sous vide setup, which only requires a beer cooler, resealable "Ziploc" plastic bags and a digital meat thermometer,  but have graduated to a digital thermostat controlling water temperature in our CrockPot. And while steak sous vide is delicious, the most striking results have been with pork chops and chicken breast  - both of which turns out very moist and tender.

2. And by "we" I really mean that my husband has done pretty much all the equipment setup and experimentation with different prep methods and meats, and I have happily eaten the results.

3. The best reference guide for sous vide cooking is mathematician Douglas Baldwin's "A Practical Guide to Sous Vide Cooking", which covers preparation, temperature selection, cooking times, and  food safety in detail.  The illustration of eggs cooked at different temperatures is especially cool (65°C eggs are the best!).

4. Blagden C. "Further Experiments and Observations in an Heated Room"   Phil. Trans. 1 January 1775 vol. 65 484-494 doi: 10.1098/rstl.1775.0048 (full free article)

Top Image: Steak ©P.Kolm; Middle Image: "Badstuga, efter illustration" (via Wikipedia);  Bottom Image: "Stranglesnake" by Arno/Coen of nutscode.com (via Wikipedia)

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Ecology in Prison

Aug 11 2010 Published by under [Biology&Environment]

Nalini Nadkarni is a biologist at Evergreen State College in Olympia, Washington who is an expert on tree canopy ecosystems. She also does a considerable amount of science outreach to the public.

One of the educational programs she organized is the Sound Science program for urban youths that combines science and music by rapper C.A.U.T.I.O.N.., which sounds like it was a lot of fun for the participants.

More unusual is her Sustainable Prisons Project, which teaches ecology and biodiversity conservation to prisoners in several Washington state prisons. The goals of the program are broad:

Our mission is to reduce the environmental, economic and human costs of prisons by training offenders and correctional staff in sustainable practices. Equally important, we bring science into prisons by helping scientists conduct ecological research and conserve biodiversity through projects with offenders, college students and community partners.

Some of the research projects that prisoners have been involved include raising endangered frogs and  figuring out to grow moss for the horticultural trade

The education isn't only academic. The program also helps prepare inmates for "green collar" work by teaching them skills like hydroponic and organic gardening, beekeeping and pest control. At least one participant hopes to work for the U.S. Forestry Service when he is released.

And Nadkarni points out that the program has emotional benefits as well, by providing the prisoners an "intellectual and physical connection to the outside world".

Here's a video about the program.

See also Nalini Nadkarni's brief TED talk.

I know this may seem like an odd first post, since I assume that most of you readers don't spend the bulk of your time in a prison cell. But I think it's a good example of how science - both the knowledge of scientific facts and the process of scientific inquiry - can have a positive impact even for populations outside of the mainstream of society.

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Viewing the world through the lens of science

Aug 11 2010 Published by under [Etc]

Spider on Eggplant

Spider resting on an eggplant in my garden.

“Fortunate is he, who is able to know the causes of things” ~ Virgil

Welcome to my new blog Everyday Biology!

I'm quite excited to be joining the other science bloggers of the Scientopia blog collective (be sure check out the Scientopia front page if you haven't done so already).

Unlike many of my fellow Scientopia bloggers, most of my daily interactions are with people who do not have a formal background in science. One thing I've noticed is that for many people "science" is something that is separate from their daily lives -  it was a subject they covered in school, and they hear occasional reports about scientific breakthroughs (or "breakthroughs") on the news, but they usually don't view their experiences through the lens of science.

Raptor on Streetlight

Suburban Raptor

I'm just the opposite - I see science everywhere I look and in almost everything I do. Since my own background is in biology, that's the usual frame through which I view the world.

I find it comforting that the universe operates in a predictable fashion, even if we don't yet understand all the details. I find beauty in nature. And I think that a scientific understanding of the world is both personally satisfying and provides practical advantages over a non-scientific worldview.

It's useful to understand which plants should thrive in the local climate, why antibiotics work, which part of a chuck roast is the best eating, or why my friends might appear to have irrational shopping habits. And it's important to be able to sort out the real from the bogus when scientific claims are used to sell quack medications or beauty products or further political agendas.

Products for the lactose intolerant

Modified bacteria produce lactose-digesting enzymes.

I'm planning to use Everyday Biology to take a look at how bioscience applies to daily life -  in health and sickness, at work and at play, at home and out on the town.

I hope you find it as interesting as I do!

On a housekeeping note, my blogroll and layout are still under construction. Don't be surprised if they change over the next few weeks.

Also, if you are interested in the biosciences in pop culture, you might like my Biology in Science Fiction blog.

Images: Eggplant and Raptor ©2010 P. Kolm. Lactaid image by Scott Bauer USDA ARS Photo Library.

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