Saturday, August 31, 2013

Mark of Cain: One Homo to Rule Them All

There are a lot of species of the Panthera (lions, tigers, panthers, etc.) genus still around. Ditto for dogs. Not so Homo. We call ourselves Homo sapiens (wise man), but our late brother species might refer to us a bit more disparagingly. One hundred thousand years ago, there were at least six human species still extant, including Neandertals, Denisovans, Homo erectus, Homo ergaster, and the hobbit people of the Isla de Flores. And of course, us, the wise guys. Quite likely, there were others, as yet unknown, or perhaps, never to be known.

It seems that we are not exactly innocent in the demise of our late bretheren. Such, at least, is the message Yuval Noah Harari, a prof at the Hebrew University of Jerusalem and the teacher of Coursera's A Brief History of Humankind

It's early in the course, but it seems that he's not that impressed with our own prospects either. Compared to erectus, who managed 1.4 million years on the planet, we only have 200 k years in, and he thinks we might be lucky to make another thou.

Friday, August 30, 2013

Guaranteed Income

From time to time Matt Yglesias pushes the idea of a guaranteed basic income as an alternative to minimum wage, welfare and various other programs. For one thing, it would do away with all the bureaucratic nuisances of welfare and minimum wage. It also eliminates the economic distortions caused by the minimum wage. Combine that with universal single payer health care, and one alleviates many of the burdens of poverty, which among other evils, effectively causes lower IQ.

Of course there are some potential difficulties, including the fact that the people who work would have to pay for it. The central problem, though, is the free rider problem. How do you avoid creating a dissipated class that won't and can't work and that lives parasitically on the rest of society? Have any rich countries tried this?

If automation continues to destroy jobs, tactics like this might become necessary for the stability of society.

Volcanoes Be Complicated: Silicon Rocks!

Like any good science nerd, I made baking soda and vinegar volcanoes as a kid. This seems to have persuaded me that nothing much was going on in volcanic eruptions. Donald Dingwell’s Coursera course on the subject has certainly disabused me of that notion. It turns out that my chemistry is more than a bit short of what’s needed to properly understand the subject, but what I can understand is really interesting.

I signed up for the course because the promised workload was small and explosions are cool, thinking that I might watch a bunch of videos of lava, pyroclastic flows, etc. Actually it turns out to be perusing a lot of complicated graphs with multiple axes plotting such things as “speciazation of water in haplogranitic glasses and melts” or “glass transition temperature at a specified sheer viscosity as a function of water weight content”. Unfortunately, I’m not entirely clear why sheer viscosity is an important thing to specify when measuring glass transition temperature, but it has something to do with a notion of equivalence. If I understand that, it in turn means that a whole bunch of properties, including sheer viscosity at the glass transition temperature, are good proxies for the structural content of the silica melt.

Silicates turn out to impressively complex. Somewhat like carbon, silicon likes to form four tetrahedrally directed chemical bonds, with oxygen in the case of silicates, and these silicon-oxygen tetrahedra are the basis of the polysilicates. Of course oxygen is not very happy with just one chemical bond, so something else is needed to glom onto, and the most obvious possibility in a silicate melt is another silicon atom, resulting in two silicon oxygen tetrahedra sharing a common oxygen. Chains of such tetrahedra can be formed, but linking of ends is thermodynamically favored, so usually triangles and hexagons of linked tetrahedra are formed. Higher degrees of linking produce sheets and solids of tetrahedra. When all the oxygen atoms are shared, four oxygen per Silicon, two Silicon per oxygen, we have SiO2.

In a silicate melt, with a good mixture of other chemical components present, the various configurations of silicon tetrahedra will be present in some sort of equilibrium mixture of structural species characterized just by temperature, pressure, and chemistry. Cooling abruptly can produce glassy states far from equilibrium, and the exact type of non-equilibrium depends on the history of the heating and cooling. Glasses are hysterical* – they exhibit hysteresis.

So why is this stuff important as well as cool? Because silicates exhibit an enormous range of viscosities (depending mainly on the relative content of the various arrangements of the tetrahedra), and viscosity is the key to understanding whether the volcano will be a mild mannered, flowing lava will obliterate your town in days or weeks, type volcano, or a hot tempered, explosive volcano that will blow your whole island to hell in seconds, type.

*Alternate title for present note

Thursday, August 29, 2013


It seems our faithful British allies are none too keen on a Syria adventure. Now Obama is really in a box (largely of his own making). At a minimum he probably now needs Congressional approval for anything he undertakes - which is as it should be.

Expect Mid East nukes, sometime soon.

WWWWD About Syria?

What Would Walter White do about Syria? I think it might go a bit like this:

First, assassinate the infant daughter of a Panda owned by the Canadian Prime Minister. This would lead, by a series of events as inevitable as they would be improbable, to Assad's being blown up while consulting with the the leaders of Russia, China, and Iran.

Wednesday, August 28, 2013

The Dumb Kid

It had been a while, but I recently found myself being the dumb kid again. This wasn't exactly a new feeling for me, but it had been a while, and I had lost the feeling. It was an edX class, and not a hard one either. For a variety of reasons, including health and other distractions, I found myself making all the dumb mistakes the that the weak students make. Forgetting when the assignments were due, and starting on them only to find that they were already due. Not quite understanding the technique, but jumping to a guess and coming up with the wrong answer as a result. Starting on the final with way too little time to complete it. Staring at a problem and seeing no magic insight come. Finding out that the BS that worked thirty years ago when my brain was more agile wouldn't cut it when crunch time came.

None of this will come as a surprise to some of my readers - Lubos, for example. Painful, but life has lots of such lessons.

Oh well.

Could Syria Be Like Iraq (And Vietnam)?

In that we get lured into a stupid war based on phony intelligence? I don't think so, but it would be foolish to discount the possibility.

There are some obvious differences. Iraq was ruled by an evil dictator who was more or less keeping the peace in his own country and not threatening the US. Iraq turned out not to have chemical or nuclear weapons - despite a consensus opinion on the former and his dubious rumors on the latter. Syria too is ruled by an evil dictator and not directly threatening the US, but it clearly has chemical weapons and has used them, killing more than 1000 people. That evil dictator is alos engaged in a war on his own people which has killed hundreds of thousands. Bush wanted war at any cost - Obama clearly doesn't (my opinion, of course).

Oh, did I happen to mention some similarities too?

Whatever intervention Obama chooses, and I really think he has little choice, a bad outcome is likely. Obama apparently does not want to affect the course of the war, or so he says. In that case, don't do anything!! Killing a bunch of people to "send a message" is bullshit. That sort of BS is even worse than letting our credibility go to crap, and I do think that's a really bad choice too.

If Obama does do something, it should materially affect Assad's ability to wage war.

Tuesday, August 27, 2013

The Real Issue in Syria

Obama drew a blurred line in the sand for Assad over chemical weapons. Assad tiptoed up to the line and danced over it, and Obama did nothing. Assad drove over the line in his pickup and set up his tent. Now Obama is trapped. The last thing he wanted was another war in Asia. He already let the military persuade him that an unwinnable war in Afghanistan could be won, and he got burned. Between his vague threat and dilatory behavior he really is stuck.

Yglesias and others have pointed out that any intervention in Syria is an extremely cost ineffective way to save lives - it's more likely to kill more people than it saves in any case. In my opinion, though, that's not the point. The real point is our other vague threat in the Middle East - the one where we (he) said that we wouldn't permit Iran to get nukes.

If Obama folds on Syria, or, more likely, settles for purely symbolic mini-strikes, Assad will see a giant green light, and so will Iran.

Of course the worst thing now is that there are no good options. If Assad loses, Syria likely becomes a failed state dominated by jihadis. If he win, Hezbullah and Iran win.

I think maybe Obama should have been more specific in his initial threat, like, "If you use Chemical Weapons we will kill your Air Force." He should probably do that now anyway.

Monday, August 26, 2013

Speaking About Giving Away Privacy

It seems my kitchen is featured in this newly celebrated video on the inadvisability of chicken washing  And to think that I've washed many a turkey in that very sink.

Sunday, August 25, 2013

Drugs and Money

Watching Breaking Bad got me to thinking about the connections of drugs, money, and crime once again. Real high level criminals go to a lot more trouble to protect the links in the chain (than in BB), going to elaborate lengths to prevent lower level people from having knowledge of higher ups, but there is one infallible and reliable link up the chain - the money.

The US has printed up a trillion dollars or so in hundred dollar bills. A nearly equal quantity of 500 and 100 Euro notes exists. No legitimate business or individual needs these. They are almost exclusively needed and used by criminal activities. Large bills, and shady banks, make organized crime possible.

Governments tend to like them because they provide seigniorage, but this could be dealt with, I think, by monetary operations.

Can anybody think of any good reason why large cash bills - or all cash - should not be done away with? In a country where almost everyone has a smart phone, cash is not needed. Those without could be issued at least special dumb phones that were essentially just debit and credit card readers.

UPDATE: At least a couple of readers thought of reasons why they didn't want to give up hundred dollar bills, or cash more generally. No doubt the Tea Party and others would scream bloody murder if any attempt were taken to downsize our bills, so I don't expect it to happen in my lifetime. That said, I'm far from sure that the right to buy expensive stuff for cash is really a vital or Constitutional right.

Punishing Innovation

Today I listened to a talk by an archeologist who lived among Peruvian Indians for some years, and discussing the subject later he remarked "Innovation is punished." He added something about the fact that a lot of cultural energy is spent on building fences - fences between us and them. The trouble with innovation, whether it's making changes in the patterns of a traditional art form or allowing gay people to marry each other, is that it tears down those fences. Those breaches in fences alter a culture, usually in ways that cannot be mended.

In modern civilized societies we perforce tolerate a whole lot of innovation, so resistance may well be futile, but it seems to be pretty ingrained in human nature.

Ellen Barry, writing in today's NYT, reported the assassination of Dr. Narendra Dhoholkar.

For nearly three decades, an earnest man named Narendra Dabholkar traveled from village to village in India, waging a personal war against the spirit world.

If a holy man had electrified the public with his miracles, Dr. Dabholkar, a former physician, would duplicate the miracles and explain, step by step, how they were performed. If a sorcerer had amassed a fortune treating infertility, he would arrange a sting operation to unmask the man as a fraud. His goal was to drive a scientist’s skepticism into the heart of India, a country still teeming with gurus, babas, astrologers, godmen and other mystical entrepreneurs.

That mission ended Tuesday, when two men ran up behind Dr. Dabholkar, 67, as he crossed a bridge, shot him at point-blank range, then jumped onto a motorbike and disappeared into the traffic coursing through this city.

His assassins have not been caught, but it's a plausible guess that someone among the many enemies he had made among those mystical entrepreneurs and conservative Hindus might be behind the murder.

Saturday, August 24, 2013

Hating On the Actors

Anna Gunn has one of the great all-time show business gigs as Skyler White in Breaking Bad. She is discovering, however, that there is a downside to creating a memorable character that engages people's deepest emotions. In her NYT Op-Ed she discusses the hatred some people have for her character and how it has even led some nut jobs to threaten her, the actress, personally. It's probably not much comfort to her to realize that this is in fact a bizarre tribute to her skill in making her character so vividly real.

I recall a couple of occasions when I encountered similar feelings. In one case, I was an audience member watching Mark Medoff's When You Comin' Back Red Rider. The actor playing the central character, the villainous, unbalanced, and explosive Teddy made such a strong impression that I disliked him personally until I was fortunate enough to take a class (a few classes, actually) from him. Later, when I was playing a part in One Flew Over the Cukoo's Nest (directed by the same guy, actually), a friend of mine asked me, seemingly seriously, "That nurse Ratchet is so evil. Don't you just want to throw her off the stage."

I can't remember exactly what I said or thought, but it was probably something along the lines of "Well Miss X is actually a lovely young actress and we all adore her" and "Wouldn't that sort of spoil the rest of the play?"

Again, though, that kind of level confusion between reality and fiction shows the power of the actor and the writing.

Tuesday, August 20, 2013

Origins of Indian Endogamy

One of India's most characteristic institutions is its division into endogamous clans, or jatis - somewhat misleading referred to as the caste system. A group of genetics researchers from Hyderabad and Boston now claim to have evidence that the endogamic system originated, or at least took shape, about 1900 years ago.

Indian ancestry is complex, but there are two major strands, the so-called Ancestral North Indians, who are related to central Asians, Middle Easterners, and Europeans one the one hand and Ancestral South Indians, who don't appear to be closely related to any outside groups. The claim is that the genetic evidence indicates that mixing between the groups began about 4200 years ago - plausibly at the time Indo-European languages arrived in India - and stopped 1900 years ago, when the Jati system took hold.

Naturally I would be interested in Arun's opinion, fortified as it is by his vast knowledge of Indian history and deep skepticism about conventional interpretations.

Aliens: Isn't It Ironic

The irony challenged have tended to get hysterical about Krugman's famous suggestion that the economy could be healed by a fake Alien invasion. He explains the context (a riff on an similarly ironic commentary of Keynes) once again here.

DeLong finds Cochrane being irony challenged (or as Krugman puts it, perhaps uncharitably, "remarkably dense").

It's unlikely to help though. The problem with the ironically challenged seems to be that they really don't - and can't - get it. Which is another reason why irony ought to be used a bit sparingly.

The Surveillance State: 1984 Comes a Bit Late

The latest stupid heavy handedness in the Snowden affair comes courtesy of the Brits. Glenn Greenwald, writing for The Guardian, has been the main reporter of the Snowden leaks, and the Brits detained and interrogated his partner David Miranda, for a day in a London Airport, confiscating his laptop, phone etc.

In this story, Alan Rusbridger recounts the bizarre story story of how government agents destroyed laptops and hard drives in the Guardian's basement. The heavy-handedness and clumsy ineffectuality of both incidents suggest either gross incompetence or an effort at intimidation, or both. It's hard to know what the hell Cameron and Obama think they are doing here, but they sure aren't covering themselves with glory or credibility.

Birthers: Anti-Revolutionary Foreign Born Cuban Colonialist Version

It seems that US Senator and Tea Party darling Rafael "Ted" Cruz is a Canadian as well as a US Citizen, and may be a Cuban Citizen as well.

He has announced plans to renounce his Canadian citizenship, thereby forfeiting his chance to become Premier, I suppose.

Oddly enough, this story reminds me of the unfortunately challenged coyote who chewed off three legs and was still stuck.

Perfectly Normal, Statistically Speaking.

Who, exactly, is normal. Bee has a meditation on this point and concludes that everybody is above average, in some respect at least. If you consider a few hundred parameters, nearly everybody is going to be an outlier in some respect. But is that the right metric? Shouldn't the real question be whether some total deviation from the mean is significantly larger than the deviation expected on the basis of chance?

The classic (but totally arbitrary) test for statistical significance is a result which would be expected purely by chance less than 5% of the time. Suppose that you have a couple of independent, random, normally distributed variables. Then almost 10% of the time (1-(.95)^2), at least one of them will be in the 5% zone. Similarly, with ten such variables, 40 % of the time at least one is in the zone, and for 100 variables, more than 99% of the time.

So if you were to assemble a bunch of the relevant variables (height, weight, strength, agility, vision, leaping ability, etc.) Lebron James is still exceptional - a veritable freak of nature - and you aren't.

Of course I'm a pretty lousy statistician, so somebody ought to check my work. Though I already know my variables aren't statistically independent.

Sunday, August 18, 2013

The Optimist

Lumo is an optimist - the kind of a guy who would get on a flight if expert opinion thought there was only a 95% chance that it would crash.

Well, it did always work for Captain Kirk.

Saturday, August 17, 2013

Scientific Medicine

Arun has lately been posting on Richard Lewontin's reflections on scientific medicine. Here is a quote that exemplifies my objection to Lewontin's argument:

The causes of the tremendous decline of mortality from infectious diseases in the last 100 years are not certain. All that is certain is that “scientific medicine” played no significant part.

Evaluating his argument depends on exactly how one defines "scientific medicine," but I'm going to argue that scientific medicine began with the statistical evaluation of treatment effectiveness. Alan Taylor:

In 1809, on a battlefield in Portugal, the first recognisable medical trial evaluated bloodletting on a sample of 366 soldiers allocated into treatment and control groups. The cure was shown to be bogus. It was the beginning of the end of pre-modern medicine.

Here is another Lewontin Fragment:

In 1828, when causes of death were first systematically recorded in Britain, the death rate from tuberculosis was nearly 4,000 per million. The rate can only be appreciated in contrast to the present death rate in the US and Britain from all causes of only 9,000 per million. By 1855 the death rate from tuberculosis had fallen to about 2,700 and continued to fall steadily so that by the turn of the century it had reached about 1,200 per million. Koch’s discovery of the causal bacillus in the 1880s had no effect whatsoever on the rate of decline, and by 1925, after the Flexner revolution in medical schools, the rate was about 800, only 20 percent of its value in 1838. Totally unaffected by the arrival of modern medicine, the death rate continued its steady drop to 400 per million until 1948 when the introduction of chemotherapy on a broad scale did indeed accelerate the decline to its present negligible level.

Note first that the collection of systematic records on causes of death is exactly the sort of thing that corresponds to what I call "scientific medicine", and that the date is quite in line with the Taylor quote. That kind of statistical data has been central to medicine ever since, and that kind of data is even more valuable than the identification of a specific causal agent to prevention and treatment. Even the modern plague of AIDS followed the familiar pattern - the Center for Disease Control and others knew a great deal about epidemiology long before the identification of the virus responsible.

Dr. Lewontin, your diagnosis is bogus.

Thursday, August 15, 2013


This marvellous map has a dot for each American, and each dot is colored blue, red, green, orange or brown for race, respectively White, Asian, Black, Hispanic, or other, including Native American, as per the US census. I live in very mixed town in a rather mixed State, but I was surprised at how segregated even my own town (Las Cruces, NM) is. My own neighborhood is mainly orange, with a strong blue presence, but some areas of the town are almost all orange and the wealthier neighborhoods mostly blue with a good dusting of orange and a dash of red. Our greens - yes, we have a few - are harder to find than Waldo.

I was pretty shocked, nonetheless, when I looked at a few American cities. They seem as ghettoized as if the Tsar had drawn the lines himself.

Tuesday, August 13, 2013

How Much Freedom of Action Does a President Have?

My guess is that it's not nearly as much as partisans think. Congress makes the laws, and a President who ignores them is very likely to be impeached - and should be. That's true even though Congress is easily stampeded into making stupid laws. Consider Guantanamo. It's a black mark on the country and Obama promised to close it. Why didn't he? Because Congress went to a lot of trouble to expressly forbid it.

Wars are another problem of the same sort. It's very hard to get out of a war even if you were elected by promising to end it. Even unpopular wars have powerful constituencies, and anybody who pulls out before the bitter end is sure to be assailed as one who has stabbed the country in the back and betrayed the sacrifice of those who have already died, been wounded, or even served.

Consider the problem of terrorism. The US has relatively small but numerically large number of Muslim citizens, who overwhelmingly are law abiding and apparently as patriotic as anybody else. A tiny fraction of that population consists of radicalized individuals who wish to damage the country. Since 9/11 we have averaged less than one significant terrorist attack on behalf of Islam per year - and a not much smaller number of anti-Islamic terrorist acts. Suppose the former number were a dozen? How long would it be before vigilante mobs began hunting out Muslims and anybody else some idiot might mistake for a Muslim - Sikhs, for example.

Are the Islamic terrorists and would be terrorists motivated by things that we, the US, actually does? Of course, but that doesn't really solve our problem. My personal belief is that we should fear the national security state - a lot - but at least in part, it may be necessary.

Is this intended as a defense of Obama? Sure, but it's also prompted by a lifetime of seeing Presidents, including some who are otherwise very smart, sucked into situations they didn't want, can't control, and don't manage to escape.

The Constitution has some powerful protections of individual rights. These rights are sometimes more honored in the breach than in the guarantee, but before we panic we ought to think and compare. Is it obnoxious if the government monitors our email? Sure, but compared to some of the things Lincoln and FDR felt they needed to do, it's very small potatoes indeed.

Monday, August 12, 2013

The GOP, Breaking Bad

One odd aspect of the human condition might be called the "berserker mode." It's a desperate, nihilistic tactic, driven by panic or madness that is willing to risk anything. Perhaps the suicide attacker is the ultimate expression of this mode, but it's far more widespread than that. The psychopath gets his effectiveness from his reckless lack of fear, of consequences or the disapproval of others. The character "Heisenberg" of Breaking Bad learns he is dying of cancer and is transformed from meek high school chemistry teacher into a murderous drug lord.

Something similar happens to whole nations. Germany and Austria at the dawn of World War II. It can happen to political parties too. The desperate nihilism of today's Republican Party has a huge component of that. People seeing the old verities of racism, that old time religion, and good union jobs collapse are the motor that powers the anti-government, anti-Obama, anti-science, anti-modern Republican base, and there are plenty of unscrupulous opportunists ready to harness that rage to power - the Kochs, the Romney's and the others.

These stories usually end badly. For everybody.

Saturday, August 10, 2013

Scientism: Pinker vs. Douthat

"Scientism" is a charge frequently aimed at those who choose a reductionist view of human nature. Stepnen Pinker thinks it's an accusation without substance - a "boo" word as he calls it. His essay in the New Republic is a forthright defense of most of the evolutionary, reductionist, and scientific ideas usually attacked as "Scientism" and a agressive rejection of notions that reliable guides to ethical behavior can be found in conventional spiritualistic notions. Among some material quoted by Douthat:

...We know that the laws governing the physical world (including accidents, disease, and other misfortunes) have no goals that pertain to human well-being. There is no such thing as fate, providence, karma, spells, curses, augury, divine retribution, or answered prayers—though the discrepancy between the laws of probability and the workings of cognition may explain why people believe there are. And we know that we did not always know these things, that the beloved convictions of every time and culture may be decisively falsified, doubtless including some we hold today.

Douthat clearly hates all this, but he doesn't muster much of an attack on it. The best he can manage is an argument that the utilitarian humanism Pinker advocates is hardly the only morality one might choose in the absence of supernatural guidance.

And his invocation of “the scientific facts” to justify what is, at bottom, a philosophical preference for Mill over Nietzsche is the pretty much the essence of what critics mean by scientism: Empirically overconfident, intellectually unsubtle, and deeply incurious about the ways in which human beings can rationally disagree.

Of course he submits exactly zero evidence for any of the "charges" in his ultimate sentence. What, if anything, does he mean "empirically overconfident"? Does it mean anything except trusting experience over mysticism? "Intellectually unsubtle" is an insult that lacks content or, if I may say, intellectual subtlety, and "deeply uncurious" is merely another almost content free insult. Does it mean anything except refusal to take mysticism seriously?

Monday, August 05, 2013

All the News...

...that five or six mega-plutocrats see fit to print (or broadcast).

Jeff Bezos's purchase of the Washington Post is another step in the complete control of all media by a few plutocrats. I don't have any idea whether Bezos is what I would call a good plutocrat or a bad (Koch) style one, but the trend is ominous.

Friday, August 02, 2013


It's clear that the Republican Party is betting heavily that they will be able to sabotage the economy until 2014 and not suffer the obvious electoral consequences. This maybe in part because Obama, the dreamer of compromise and accomodation, lacks the confidence to forthrightly challenge them. When they themselves have been in charge, they usually show themselves to be both spenders and Keynesians.

Meanwhile Obama will continue to propose modest job promoting policies and good naturedly complain about the failure of "Congress" to pass his programs. How about showing just a little spunk and FDR, Mr. President? Name names and be specific. Talk about just how many jobs have been cost by the Congressional Republican's sabotage - and call it by it's name.

Thursday, August 01, 2013

Physics Under The Dome

I got hooked on the new CBS TV serial, Under the Dome (Monday Nights). The suspense led to the Stephen King novel on which it is based. In the afterword, King makes a big point of noting his medical advisors, who ensured, I suppose, that he got the gruesome details right on the countless catstrophes he inflicted on his characters. But we won't worry about that here, or about the literary merits of the novel as a whole - what we care about is the physics.
Not the physics of the Dome - we don't learn anything about that - the physics of life under the dome.
** ** **
The climactic catastrophe of the book is based on a monstrous explosion producing a giant fireball that spreads over most of the dome with terrible carnage, leaving the few survivors with no oxygen to breathe. Do the numbers add up?
In the book, the town of Chester's Mills is suddenly enclosed in a dome, impenetrable to anything they can throw at it, but transmitting sound, electromagnetic radiation, and somewhat permeable to air and water. The area enclosed is perhaps 10 or 20 square kilometers - call it 10^7 m^2. The maximum height is about 15 km, so the enclosed volume is something around 10^11 m^3 - 100 billion cubic meters.
The explosion was produced mostly by 10,000 gallons of propane - the fuel supply of an enormous Meth lab.
How much heat would that evolve? Complete combustion of one gallon of propane produces about 100 million Joules of heat, so 10,000 gallons produces something like a trillion Joules. For comparison, on a sunny October day at noon in Maine (the setting)the ground might receive 400 J/sec per sq meter, or 4 billion J/s for the whole area enclosed by the Dome. The propane would thus release the equivalent of about eight minutes sunlight for the whole Dome. That's a bunch, but not a Dome wide firestorm type bunch.

When I was a student, a guy had a fight with his wife and ran his car into the middle of a gasoline tanker truck not far from where I lived. The fireball melted the pavement and set fire to a couple of nearby roofs, but the tanker driver escaped by kicking out his front window and running like hell. Those trucks carry five or ten thousand gallons of gasoline, and gasoline has an energy content that is similar to (but slightly lower than) propane.

How about the notion that the fire would use up all the oxygen? Propane has 3 carbons and 8 hydrogens, so complete combustion consumes 10 Oxygen atoms (5 O2 molecules), producing 3 CO2 + 4 H2O. Hence each molecule of propane (molecular weight 44) gobbles up Oxygen atoms of total molecular weight 160, and so a gallon of propane, at a bit less than two kilograms, would consume rather less than 8 kilograms of Oxygen, or 80,000 kilos of Oxygen all told. Sea level air has about 0.2 kg of Oxygen/m^3, so the whole enterprise consumes the Oxygen in 400,000 m^3 of air - a pittance compared to the 100 billion m^3 in the Dome - even if you allow for the fact that the upper levels contain much smaller masses of air.

What about the 78,000 or so kilos of CO2 produced? It's a bunch, but not too bad compared to 50 billion or so kg of air in the dome - only about 2 ppm - not even a major local warming threat.
The complete combustion assumed above is highly unlikely. In the scenario of the book, even if most or all of the propane vessels were breached in the initial or subsequent explosions, the fuel-air mixtures would mostly lack enough oxygen for combustion.

Propane tanks are tough. Mythbusters took them on in this episode. Explosions at the Blue Rhino plant in Tavares, Florida destroyed many of the more than 50,000 20 gallon tanks stored there, but the 3 thirty thousand gallon tanks survived. This video captures far larger propane explosions in Korea, but even they are much too small to produce the kind of widespread catastrophe King describes.