Tuesday, January 31, 2012

Potash


Canada is the largest producer of potash in the world. Recent investment in the development of potash resources in Saskatchewan is raising the usual issues of economic prosperity vs environmental sustainability. As potash is becoming a larger part of the Canadian economy I thought that I would share what I learned about potash because I knew essentially nothing about it until recently.
Before the late 1800s, potash was produced by leaching salts from the ashes of wood or plants and boiling the solution in a pot, hence the name potash. Historically, Canada was a large producer of potash as the frontier was opened up and deforested. Excess wood was burned and brought to asheries, where the ash was converted to potash.
Modern methods exist to obtain potash from mineral deposits and Canada has the largest reserves of these deposits in the world. The deposits are the result of the complete evaporation of sea water and the deposition of crystallized salts in beds of ore, called sylvinite. This ore consists of a mixture of sodium and potassium chloride (NaCl and KCl). The KCl is then purified using various processes and sold as potash.
Due to historical methods of production potash can refer to various salts of potassium, however mined potash is largely KCl. The element potassium derives its name from potash.
The majority of potash is used in fertilizers. Plant growth is often limited by available potassium. Therefore there is no substitute for potash and in a world of seven billion it is essential for food production. The best we can do is ensure that Canada responsibly extracts this valuable resource.


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Real Space Lego

I was very impressed with the Lego-astronaut of Mathew Ho and Asad Muhammad. These two seventeen year olds from Scarborough sent a Lego man 24km above the surface of the earth. Using a weather balloon, some long ropes, a cellphone GPS, Styrofoam, cameras and some patriotic Lego they captured some spectacular footage. The footage has captured widespread media attention. It is amazing that the technology for what is essentially an unmanned space probe is within the budget of two smart seventeen year olds.


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Tuesday, January 24, 2012

Asilomar Conference on Recombinant DNA

The recent call for a 60 day moratorium on engineered avian flu virus research reminded me about the Asilomar Conference.
The Asilomar Conference on Recombinant DNA was held in 1975 and its purpose was to establish guidelines for safely working with new recombinant DNA technology. The need for such a conference was instigated in 1974 by the construction of a bacterial plasmid that was deemed potentially hazardous. This plasmid contained elements from the monkey virus, SV40, which had been shown to cause cancer in mice. The idea of transforming this plasmid into a bacterium caused enough concern that a worldwide moratorium on recombinant DNA technology was called for by American scientists. The goal of the Asilomar Conference was to establish the conditions under which research in this area could continue. Many recommendations for experimental protocols were agreed upon. Additionally, three kinds of experiments were to be deferred until a later date. These experiments that were deemed too risky were cloning of genes from highly pathogenic organisms, cloning of toxic genes, and large scale production of gene products harmful to humans, plants or animals. Some of these kinds of experiments are now done routinely, and I do not know if there was ever a consensus of when it was determined these experiments were safe.
By taking initiative, the Asilomar Conference avoided potential governmental or other regulatory involvement that may have severely limited recombinant DNA technology in the long term. Instead, a timely relaxation of the guidelines, as knowledge about the true risks of these experiments accumulated, was a perfect fit for scientific progress.
Interestingly, I have spoken with scientists who were doing recombinant DNA research at the time who said that, in reality, the moratorium was not observed. Research continued in the field as it was an exciting and competitive time. I was also told during this time recombinant plasmids were exchanged between researchers by drying them on paper and mailing them, a practice still done occasionally today.
While there are some definite differences between these two calls for halting research, the current call for a moratorium on avian flu virus research has similar goals as the moratorium on recombinant DNA research. I think it would be a success if it had similar outcomes to the Asilomar Conference.
Certainly the moratorium has different goals than the censorship of two recent H5N1 papers, which is directed at stopping the dissemination of information about specific transmission determinants of H5N1. I have read a couple of articles that seem to get confused about the goals of this censorship and the goals of the recent moratorium. Indeed the current call for a moratorium doesn't mention the word terrorism or suggest censorship as a security measure.


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Tuesday, January 17, 2012

Ski Wax Science


According to a thesis published in 2006, ski wax is snake oil. Leonid Kuzmin is the author of a couple of papers, both included in his thesis from Mid Sweden University (pdf), that demonstrate that many practices designed to decrease friction between nordic skis and snow are counterproductive. It is the authors assertion that waxing practices evolved when skis were made of wood and that a critical re-examination of these practices was lacking when wood was replaced with modern plastics. The data in the thesis suggest that there is no advantages to waxing skis. At best, the data suggests, an improvement in glide is observed for the first 200m. After this point, a waxed ski picks up debris increasing friction with the snow to the point where it becomes slower than an unwaxed ski. The thesis also pokes holes in two other commonly held beliefs, that wax protects skis from water penetration and offers protection from abrasive wear. While this work was done exclusively with nordic skis, it is the authors belief that the findings hold true for alpine skis.
It is not hard to find lots of passionate anecdotes refuting his findings, however I was surprised that there was no real scientific studies demonstrating benefits of waxing skis.

From the thesis:

Skis treated with any established waxing procedure loose their glide ability faster than the reference skis (dry skis).

A typical counterpoint found in internet forums:

I was in a hurry to get to Sun Peaks a while ago. My skis needed waxing but I didn't do it so we could get on the road. On our first day I was having trouble getting a good slide going and I had to continuously pole and skate to get up over a hump to get to a particular face. That night I waxed my skis. The next day with essentially the same snow conditions I flew over that hump so fast I had to brake at the top, and I certainly didn't need to pole or skate. Wax works.

Despite this thesis, now 5 years old, most skiers get their skis waxed or do it themselves. I wonder if this is a case where the mantras and anecdotal evidence are winning in terms of acceptance or if the studies just did not get publicized well. Perhaps the first 200m where a waxed ski glides better is the source of much of the anecdotal arguments for waxing. Personally, I think much of the resistance to accept these findings is due to the fact that waxing skis can be an enjoyable process. Waxing your skis gets you excited to go skiing. I actually miss it.



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Wednesday, January 11, 2012

The Drag Effect

The skip of my curling team competed in the Brier a few years ago. I make him look pretty talented. Recently he was talking about the drag effect. The only thing I understood about it during our match is that when two stones are touching they do not behave exactly like billiard balls.
Take a look at this shot.



That is not how billiard balls would have behaved in that situation. Basically, the struck rock and the yellow rock behind it were frozen together on their striking surface. The struck rock then transfered some of its momentum to the yellow rock. A more detailed explanation of the drag effect is available here.


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Sunday, January 08, 2012

Flynn Effect

The Flynn Effect is the observed steady, widespread increase in IQ over generations. In some places this has been occurring for at least 100 years. In fact, if you were to give your great grandparents a modern IQ test, they would test below 75 and be considered mentally challenged. The Flynn Effect is not simply an increase in "crystallized" intelligence due to the increasing availability of knowledge. The way in which IQ scores are increasing is described in a recent Wired article:
1) Scores have increased the most on the problem-solving portion of intelligence tests.
2) Verbal intelligence has remained relatively flat, while non-verbal scores continue to rise.
3) Performance gains have occurred across all age groups.
4) The rise in scores exists primarily on those tests with content that does not appear to be easily learned.
The reason why IQ test results are increasing is a mostly unresolved question and presents some paradoxes described by Flynn and summarized here.

The intelligence paradox: The Flynn Effect suggests that we are getting smarter relatively quickly, but it’s not obvious (and some would say flies in the face of certain evidence) that kids today are so much smarter than their parents or grandparents (except perhaps when it comes to home electronics). As Flynn writes:

If huge IQ gains are intelligence gains, why are we not stuck by the extraordinary subtlety of our children’s conversation? Why do we not have to make allowances for the limitations of our parents? A difference of some 18 points in the average IQ over two generations ought to be highly visible.

The mental retardation paradox: If the rate of change in IQ is extrapolated backwards, it suggests that people in 1900 had a mean IQ score somewhere between 50 and 70 judged by today’s standards. An IQ level of 75 is typically considered ‘mentally retarded.’ Flynn puts this one nicely, too: ‘Either today’s children are so bright that they should run circles around us, or their grandparents were so dull that it is surprising that they could keep a modern society ticking over.’

The identical twins paradox: Twins raised apart tend to have very similar IQ scores, typically considered strong evidence for a genetic basis for differences in IQ. The Flynn Effect instead suggests that intelligence, if it is being measured by IQ, is more malleable and subject to environmental effects. [Clearly there is no genetic evolution basis for the Flynn effect, mostly obviously because the effect occurs too fast, over a single generation.]

The most popular theories as to the cause of our collective increasing genius include:

  1. Increased schooling and test familiarity – This seems like an obvious cause, however it has been shown that previous generations with similar levels of education still score lower than subsequent generations.
  2. Generally more stimulating environments – Our world is increasingly complex, potentially increasing exposure to problem solving situations.
  3. Nutrition – Improved nutrition has increased human stature. It is therefore possible that improved nutrition is also responsible for increases in IQ. Recent evidence outlined in the previously linked Wired article suggests that both ends of the bell curve are showing equal increases in IQ. An increase in IQ of those at the right side of the bell curve argues against a solely nutritional cause as those with a high IQ are likely not undernourished to begin with.
  4. Infectious diseases - The decrease in infectious diseases experienced during development of the brain may be responsible for the Flynn Effect. Fighting off a disease and brain development are both metabolically costly and perhaps early childhood infections might come at a cost to brain development. This perhaps has the same problem as the case for a nutritional cause outlined above.
  5. Heterosis - The genetic component of IQ is so great that some argue that environmental causes would have a minimal effect. Essentially the idea is that the increased mixing of human populations has lead to a "hybrid vigour" effect in population IQ.
These are not the only ideas for a cause of the Flynn effect. It is very possible that the Flynn effect has a complex combination of causes.

Another very interesting aspect of the Flynn Effect is that it has stopped in many developed nations. The cause is unknown.


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Friday, January 06, 2012

Infectious salmon anemia



The poor 2009 sockeye salmon return in the Fraser River, mentioned previously on the bayblab, prompted the Cohen Commission in order to better understand what happened. The final report of the Commission is due this year but in the meantime there is a large amount of information about the ongoing findings of the Commission available here. Many potential causes are being examined, however much of the media coverage of the commission has focused on the possible role of infectious salmon anemia (ISA). The possibility of the presence of this virus in wild pacific salmon has become very political and has resulted in accusations of attacks on scientific credibility. It would certainly have implications for the controversial salmon farming operations in the area.
As the name implies the virus causes anemia by infecting red blood cells of infected salmon and has an extremely high mortality, as high as 90%. This virus is commonly associated with atlantic salmon farms and has affected farming operations all over the world in recurrent epidemic outbreaks. Spread of the virus between farms can be examined by correlations between seaway and genetic distances between viral isolates.
ISA is an Orthomyxovirus, like influenza, and therefore has a small segmented negative sense single stranded RNA genome. This genome arrangement allows for reassortment when a cell is superinfected, and confers the ability of the virus to rapidly change in a population, much like influenza. Hopefully this virus is unlike influenza and will not successfully cross the species barrier and maintain a high mortality in pacific salmon.
On a positive note, it is possible that a local ISA strain has been in pacific salmon species for years. It would be interesting to know to what degree it is genetically related to the ISA found in atlantic salmon farms. Fortunately it has also been demonstrated that pacific salmon are highly resistant to previously characterized ISA (pdf).


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