MGTutoring.com. A Rational Perspective on Education.

January 7, 2010

Horses and Cold

Filed under: Animals, Biology, Horses — Administrator @ 1:32 pm

In “How Horses Cope With Cold,” Heather Smith Thomas says:

Horses handle cold weather better than humans do; equines evolved in the cold climates of northern Europe and Asia. Their natural “comfort zone” (energy-neutral temperature zone, in which they don’t need to expend extra energy to maintain normal body temperature if weather is not wet or windy) is from about 15 to 60 degrees Fahrenheit. The horse’s body is better at creating and conserving heat in cold weather than dissipating it in hot weather.

Horses have a normal body temperature of about 100 degrees Farenheit (38 degrees Celcius). They maintain this temperature in cold weather with the help of several mechanisms which include shivering, changes in hormone levels, increased body metabolism, increased digestion of fiber (adding more fiber or more protein to the diet can help a horse keep warm, since digestion of these nutrients produce heat), growing longer and thicker hair which can stand up on the skin to make a layer of insulating air pockets, increased feed consumption, and increased activity. Cold horses on a frosty morning often run and buck to warm up.

If the horse gets cold, the blood vessels in his skin constrict to minimize heat loss, and the hair shafts stand on end for better insulating. If he continues to be cold, he starts to shiver, with his muscles rapidly contracting and relaxing–which quickly raises his metabolism rate and amount of fuel burned in the muscles. With his large blocks of muscle, the horse can shiver much more readily and more comfortably than a human. Since most of this muscle action is being converted to heat, this is a very effective way to warm himself. It takes a great deal of energy, however, to shiver for a prolonged period; this can use up his energy stores.

Read the rest. Good stuff. I’d have like the essay better if there were references to actual scientific research and articles at the end.

The last sentence and paragraph is fascinating; it’s all physics, chemistry, and their application in biology: the theory of insulation; the theory of thermodynamics; the law of conservation of energy; the conversion of chemical energy to mechanical energy to heat.

This is a topic I’ll need to look into more, to see how this is all consistent with science and evolution.

Update (9:30 PM):  Note that it is the air trapped in the horse’s hair that provides most insulation (air is a poor thermal conductor when no convection takes place). We use the same principle in double-paned windows, and in dressing in layers.

Update (10:43 PM):  In “Cold Weather Horse Care Review” (TheHorse.com, January 05 2010, Article # 15582), Liz Brown writes:

Water is essential for regulating body temperature, said Greg Meyer, extension educator for large animals at Ohio State University. “We typically think of keeping horses cool with water, but water is required for energy for keeping them warm as well.”

Copyright © 2010 BLOOD-HORSE PUBLICATIONS. All rights reserved.

And in “Cold Weather Nutrition” (TheHorse.com, February 01 2008, Article # 11409), Kimberly Peterson, DVM, writes:

Generally, horses at rest in ambient temperatures of 70°F consume 2% of their body weight in roughage (hay) per day. A 1,100-pound horse will eat approximately 22 pounds of hay per day. Assuming an energy density of 1.0 Mcal/lb, which is typical of many hays, this equates to approximately 22 Mcal or 22,000 Kcal.

Roughage in the diet is the main source of heat for the horse. The bacterial fermentation of fiber in roughage, occurring in the large intestine, results in the majority of heat produced during digestion.

Added fat in the form of vegetable oil is an efficient calorie source at 4 Mcal/pound (four times the energy of hay). Up to 12% of the day’s total calories in the form of fats and oils is well-tolerated. While fat digestion releases almost no heat, it provides calories for energy and the maintenance of body condition (1 cup vegetable oil=2 Mcal).

Copyright © 2010 BLOOD-HORSE PUBLICATIONS. All rights reserved.

November 23, 2009

Science, Sugar, and Life Span

Filed under: Biology, Exercise, Health & Nutrition, Science — Administrator @ 11:19 pm

Charles Washington said in “Spoonful Of Sugar’ Makes The Worms’ Life Span Go Down“(Zeroing in On Health – The Blog!,  11-12-09):

By adding just a small amount of glucose to C. elegans usual fare of straight bacteria, they found the worms lose about 20 percent of their usual life span. They trace the effect to insulin signals, which can block other life-extending molecular players.

Although the findings are in worms, Cynthia Kenyon of the University of California, San Francisco, says there are known to be many similarities between worms and people in the insulin signaling pathways.

“In the early 90s, we discovered mutations that could double the normal life span of worms,” Kenyon said. Those mutations effected insulin signals. Specifically, a mutation in a gene known as daf-2 slowed aging and doubled life span. That longer life depended on another “FOXO transcription factor” called DAF-16 and the heat shock factor HSF-1.

Although we do not fully understand the mechanism by which glucose shortens the life span of C. elegans, the fact that the two mammalian aquaporin glycerol-transporting channels are downregulated by insulin raises the possibility that glucose may have a life-span-shortening effect in humans, and, conversely, that a diet with a low glycemic index may extend human life span,” the researchers write. Kenyon also points to recent studies that have linked particular FOXO variants to longevity in several human populations, making the pathway the first with clear effects on human aging.

© Zeroing In On Health – The Blog!.

Update (11-24-09, 8:20 AM):  See also Worms and Stress: Live Long and Prosper by Petro Dobromylskyj, at his blog Hyperlipid. An excerpt:

This is how this research group view the impact of their work on diabetes management:

“In light of our findings, the current body of evidence tentatively calls into question the efficacy of increasing cellular glucose uptake in diabetics and suggests that other methods of lowering blood glucose (Isaji, 2007; Wright et al., 2007) may be preferable to achieve normal life expectancy in human type 2 diabetes patients.”

The two refs cited refer to techniques for extracting glucose through the kidneys or possibly reducing its uptake through the gut. No consideration seems to be given to not actually putting quite so much glucose in to the system in the first place!

Read his post and the comments, and follow the links. Good stuff.

Update (11-24-09, 10:50 AM):  Here are some cookie recipes; cookies wheat-grainless and sugarless (or at least capable of being made so):

1.  Chocolate chip cookies and more from Elena’s Pantry

2.  Assorted cookies from This Primal Life

3.  “Caveman Cookies” from Son of Grok

4.  Almond cookies from Mark’s Daily Apple

Search through those Websites and you’ll find more good eating.  See also RecipeZaar and Paleofood (like their cookie recipes).

Update (11-24-09, 2:190 PM): Forgot to give a hat tip to Mark’s Daily Apple for bringing the Charles Washington post to my attention. And to Marnee D and Valda R for bringing the Dobromylskyj post to my attention.

October 11, 2009

Ardi on the Discovery Channel

Filed under: Announcements, Biology, Science — Administrator @ 8:02 am

Tonight the Discovery Channel will play the show “DISCOVERING ARDI: Changing Our Understanding of Human Origins.” They say about the show:

Following publication in the journal Science on the discovery and study of a 4.4 million-year-old female partial skeleton nicknamed “Ardi,” Discovery Channel will present a world premiere special, DISCOVERING ARDI, Sunday October 11 at 9 PM (ET/PT) documenting the sustained, intensive investigation leading up to this landmark publication of the Ardipithecus ramidus fossils.

UNDERSTANDING ARDI, a one-hour special produced in collaboration with CBS News will air at 11 PM (ET/PT) immediately following DISCOVERING ARDI. The special is moderated by former CBS and CNN anchor Paula Zahn and includes research team members Dr. Tim White, Dr. Yohannes Haile-Selassie, Dr. Giday WoldeGabriel, Dr. Owen Lovejoy, and science journalist Ann Gibbons

The scientific investigation began in the Ethiopian desert 17 years ago, and now opens a new chapter on human evolution, revealing the first evolutionary steps our ancestors took after we diverged from a common ancestor we once shared with living chimpanzees. “Ardi’s” centerpiece skeleton, the other hominids she lived with, and the rocks, soils, plants and animals that made up her world were analyzed in laboratories around the world, and the scientists have now published their findings in the prestigious journal Science.

Copyright © 2009 Discovery Communications, LLC.

The two-hour special will also air on October 12th, 15th, and 16th.

October 9, 2009

Health, Flu, Vitamin D, Diet and More

Filed under: Biology, Exercise, Health & Nutrition, Mathematics, Science — Administrator @ 8:08 am

I’m convinced that vitamin D3 and a change in diet has improved my health, immunity, and biochemistry. Well, as convinced as one can be without running scientific experiments on oneself, or doing some rough controlled experiments. I’m basing my conviction on personal experience, friends’ experience, and the science I’ve read on Dr. Eades’ Website, Dr. Harris’ Website, Dr. Guyenet’s Website, and others.

Note how this all demonstrates the practicality and pro-human-life nature of science and mathematics, without which I could never know what I do about health.

Here are some personal anecdotes (which, while not reaching the status of scientific experiment, are still informed by principles of induction):

1.  I used to get sick (catch a cold or feel like I was coming down with one; I don’t mean sick to my stomach) if I’d work out at the gym after skipping lunch, even if I had a good breakfast. I recall one time when I worked out under those conditions, then sat down at my computer to do some work until I became hungry. After an hour, I was not hungry yet. But after an hour and a half or two, my vision started to black out in the center, so that I couldn’t see what I was typing. At that point, I made dinner!!

But since I changed my diet and started taking vitamin D3, this no longer happens. I can skip breakfast and lunch, then work out, and be fine for hours — no blacking out of vision, no getting sick. What’s more, I can fast for 24 hours, but stay energetic and clear-headed. Once upon a time, I never would have thought I could fast that long, and never would have tried. And I used to hate, hate, hate to go to bed hungry. Now sometimes I *want* to go to bed hungry.

2.  In tutoring students, I am around students who are sick, of course. But, recently, I have not come down with anything. I know I have picked stuff up from some students because one weekend I had two periods lasting about half hour to an hour where I was sneezy and feeling like I was coming down with something. But I never did. This was a shocker; in years of prior experience, feeling like I had those two times always had led to being sick. The only/major differences between now and then are vitamin D3 and diet.  On the recent days when I was around students who were sick, by they way, I increased my dosage of vitamin D3 to 6,000 to 10,000 IU. (I recently bought some vitamin C, with 1,667% of the “recommended” daily amount; I save it only for days when I’m around someone who is sick.)

In other words, that’s “not getting sick, courtesy of science and mathematics.”

I take 2,000-5,000 IU per day of vitamin D3, unless I’m going horseback riding, in which case I don’t take any — I get plenty of vitamin D made by body + sunshine. (In a prior blog post, I linked to a vitamin D calculator, which you can check out, if you are interested.)

(more…)

October 2, 2009

Introducing Ardi, Ancestor of Lucy

Filed under: Biology, Logic, Mathematics, Science — Administrator @ 8:12 am

In “Before Lucy came Ardi, new earliest hominid found” (Yahoo News, Thu Oct 1, 6:33 pm ET), Randolph E. Schmid says:

The story of humankind is reaching back another million years as scientists learn more about “Ardi,” a hominid who lived 4.4 million years ago in what is now Ethiopia. The 110-pound, 4-foot female roamed forests a million years before the famous Lucy, long studied as the earliest skeleton of a human ancestor.

This older skeleton reverses the common wisdom of human evolution, said anthropologist C. Owen Lovejoy of Kent State University.

Rather than humans evolving from an ancient chimp-like creature, the new find provides evidence that chimps and humans evolved from some long-ago common ancestor — but each evolved and changed separately along the way.

“This is not that common ancestor, but it’s the closest we have ever been able to come,” said Tim White, director of the Human Evolution Research Center at the University of California, Berkeley.

Copyright © 2009 The Associated Press.

Copyright © 2009 Yahoo! Inc. A

There are articles regarding Ardi in TimeNational Geographic,  the New York Timesand more.

Science Magazine has made available the 11 articles for free; you can download them in pdf format.

You can also listen to a 45-minute audio interview with Dr. Tim White on the Website of the American Association for the Advancement of Science, which links to other goodies on their page announcing Ardi.

The hierarchy of knowledge behind understanding Ardi is amazing. In terms of discoveries in history, it reaches back hundreds of years…

October 1, 2009

The Power of Concepts

Filed under: Biology, Logic, Mathematics, Science — Administrator @ 9:00 am

In “Tiny parasite may have done in mighty T. rex” (Chicago Tribune, September 30, 2009), William Mullen writes:

CHICAGO – Sue – the biggest, meanest, meat-eating dinosaur known to history – probably was killed not by some other monster killer battling with her 65 million years ago, but by a tiny, one-celled parasite that gave her a sore throat.

That is the conclusion drawn by an international team of scientists who studied holes in the jaw of Sue, the biggest, most complete Tyrannosaurus rex fossil ever found and one of the star attractions at Chicago’s Field Museum.

The holes in Sue’s mandible bones at one time were thought to be bite marks by another T. rex during a fight sometime during her life. A paper published Tuesday in the online science journal PLoS says instead that the holes were made by a parasitic infection called trichomonosis, which continues to cause fatal disease in modern-day carnivorous birds known as raptors – hawks, eagles and osprey.

(c) 2009, Chicago Tribune.

Perceptually, all Sue would have been to us was pieces of rock. Conceptually — with science, mathematics, and measurement — the individual pieces of rock become classifiable as old bones based on their shape (i.e., their geometry); they can then be compared and contrasted (based on geometric shape, size, density, structure, etc.) with the bones of living (or recently deceased) animals to grasp that the rocks make up a whole, a skeleton; and with more knowledge (biology, zoology, botany, evolution, chemistry, physics, mathematics) they can be used to grasp what kind of animal had the bones, how the animal lived and moved, what it ate, and when it lived. All we know about dinosaurs is based on our ability to conceptualize, and therefore, ultimately, on measurement and mathematics.

September 28, 2009

Ape Intelligence

Filed under: Animals, Biology, Science — Administrator @ 7:58 am

NOVA and National Geographic made a fascinating documentary entitled “Ape Genius,” in which they showed how apes learn and how they function mentally. In one segment of the show, they compared how chimpanzees and human children learn and function; someone posted videos on YouTube in two parts: child vs chimpanzee, part 1 and child vs chimpanzee, part 2. There are also some fascinating, interesting segments on problem solving in apes and learning by imitation. You can watch the whole show (one hour, divided into six parts) on NOVA’s Website. They give you the option of watching it in Quicktime or Windows Media.

On a related note, National Geographic has an article (which I have not read) entitled “Almost Human,” by Mary Roach. They also have some interesting video clips on ape intelligence.

Another good segment, from National Geographic’s “Human Ape,” is about self-recognition.

September 25, 2009

We Don’t Eat Meat Because We Are Human; We Are Human Because We Eat Meat

Filed under: Biology, Exercise, Health & Nutrition, Mathematics, Science — Administrator @ 7:55 am

In “Are we meat eaters or vegetarians? Part II” (21. September 2009, 22:32 Uhr), Dr. Michael Eades says:

In April 1995 an article appeared in the journal Current Anthropology that was an intellectual tour de force and, in my view, an example of a perfect theoretical paper.  “The  Expensive-Tissue Hypothesis” (ETH) by Leslie Aiello and Peter Wheeler demonstrated by a brilliant thought experiment that our species didn’t evolve to eat meat but evolved because it ate meat.

In keeping with a great scientific tradition, Aiello and Wheeler were able to see what they saw because they stood on the shoulders of giants who came before them.  In their case the giant was Max Kleiber, an animal physiologist working at the University of California at Davis, who published a groundbreaking paper in 1947 and a scholarly text titled The Fire of Life in 1961.  Kleiber’s work involved the meticulous measurement of the metabolic rates of numerous animals, including humans.  As he plotted the various metabolic rates, he discovered an extremely strong correlation between the mass of an animal and its metabolic rate.  Kleiber found that this relationship held constant across numerous species.  His October 1947 paper in Physiological Reviews simply titled “Body Size and Metabolic Rate” was a classic.  By using the equations Kleiber worked out, the metabolic rate of virtually any animal could be determined simply by knowing the animal’s body size.

Since all animals measured have conformed to Kleiber’s law, Aiello and Wheeler postulated that animals now extinct – including our human and pre-human predecessors – would have fallen along the same line. Using skeletal remains paleontologists have been able to calculate body sizes of extinct animals along with pre-Homo and early-Homo species.  Then using Kleiber’s law, it is possible to closely estimate the metabolic rates of these creatures.  And here’s where it gets interesting.

According to Kleiber’s law, an australopithecine weighing 80 pounds would have the same metabolic rate as a human weighing 80 pounds despite the disparity in brain size between the two.  The much larger brain of the human would have 4-5 times the metabolic rate of the brain of the australopithecine, yet would have the same overall metabolic rate.  What gives?

The Blog of Michael R. Eades, M.D. © mreades 2009

Read Dr. Eades’ article to find out the answer! And more! It is a fascinating article.

Some of the development and hierarchy of science is made clear in it. But to see where it all came from, we’d have to trace this back to the work to study human metabolism in the first place, to Joule’s work in the mechanical equivalent of heat, to Mayer’s work in the conservation of energy principle, to Harvey applying mathematics to biology. And to the development of the math that made the knowledge possible in the first place.

September 24, 2009

The Metabolism of Muscle

Filed under: Biology, Exercise, Health & Nutrition, Mathematics, Science — Administrator @ 11:26 am

In a comment to Dr. Michael Eades’ post “Are we meat eaters or vegetarians? Part II” (21. September 2009, 22:32), Gabe says (at 22. September 2009, 20:26):

Thanks for the comments Mike. You know I had to try to check some numbers myself… though not very thoroughly tonight. I did find, however, a couple of references that suggest that muscle metabolic rate is indeed ‘not all that’, and it may be overestimated in most cases. In one reference (Am J Clin Nutr 2006;84:475–82) [http://www.ajcn.org/cgi/reprint/84/3/475], Robert Wolfe suggest that “every 10-kilogram difference in lean mass translates to a difference in energy expenditure of 100 calories per day, assuming a constant rate of protein turnover.” That’s only about 10 cal/kg muscle (or ~5 cal per pound of muscle!). The other reference, a bit older (Obes Res. 2001;9:331-336) [http://www.nature.com/oby/journal/v9/n5/pdf/oby200142a.pdf], the authors propose a classification scheme founded on body composition level (whole-body, tissue-organ, cellular, and molecular) and related components as the resting energy expenditure predictor variables. Rather technical but if some of the equations are applied to muscle, then we find that muscle the daily metabolic rate for muscle is just about 6 calories per pound per day, not very far from Wolfe’s predictions and very low indeed!

I can see how this could lead to the notion of ‘exercising is a waste of time’. While the increase in metabolic rate is modest at best (or right out low…), at least is higher than the metabolic rate of a similar weight of fat, which is about 2 calories per pound per day. Perhaps the lesson is that the right kind of exercise (resistance in this case, and probably more on the heavier side of weight training) improves body composition by burning more calories than fat in the hours after exercise and by preserving lean body mass while dieting for weight loss. In any case, certainly there may not be such thing as three extra pounds of lean muscle burns about 10,000 extra calories a month as I seem to remember from “Power of 10: The Once-a-Week Slow Motion Fitness Revolution”.

The Blog of Michael R. Eades, M.D. © mreades 2009

As in the previous post, we could not grasp these facts without…math!! (And physics. And chemistry. And philosophy.) How ubiquitous math is, but how perplexing it is that people don’t grasp how math useful is.

Some Comments On Fat, Cholesterol, Sugar, and Body Composition

Filed under: Biology, Exercise, Health & Nutrition — Administrator @ 11:24 am

In response to “Are we meat eaters or vegetarians? Part I” (11. September 2009, 1:17) by Dr. Michael Eades, some commenters say:

Stefano, 12. September 2009, 4:11
We once did a study (in fact, our clinic had the largest number of subjects in this study of any center in the world) on a fat blocking agent that ultimately passed the FDA and is now available. Subjects in this study could be on no medications. We had a terrible time keeping patients in the study because these subjects – on an artificial low-fat diet because the drug blocked fat uptake – got depressed, went to their regular doctors and got put on antidepressants. It was a common, common occurrence. It’s shouldn’t be a surprise, though, when you consider that the brain is primarily fat and contains an enormous amount of cholesterol. One would think – if one thought rationally – that depriving the brain of these substances would have consequences.

Walter Norris, 12. September 2009, 11:23
I don’t believe that increasing protein intake drives the production of sugar, unless you need the sugar. You require about 200 g of sugar per day. Protein converts to sugar at the rate of about 0.8g sugar per g of protein, so you would need to get 100 g of protein per day to make 80 g of sugar, which would still leave you short of the 200 g you need. Plus you need some protein just to replace the wear and tear on the tissues. By the time you add it all up, it’s difficult to get enough protein to make sugar and replace wear and tear and produce excess blood sugar. And that’s even if excess protein result in excess sugar, and I don’t think it does.

How do we know? Where does this come from (cognitively)? There is a broad, deep chain of reasoning behind these comments, taking us into biology, chemistry, physics, mathematics, and philosophy. Beautiful.

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