Friday, August 21, 2015

Computer software bugs caused the air traffic control problems at Washington Center

Here is a link to the FAA press release.

There is a moral to this story - and it involves trusting automated systems to do what you expect them to do or the appropriateness of what they are programmed to do.

The Washington Center air traffic control problems and the crash of Air France 447 both involved computer software problems.

The Washington Center problems were caused by a bug - the software had an error that prevented it from doing what the programmers intended.

The Air France crash was caused in part by software that did what the programmers intended.  There, the problem was the failure of the programmers to appreciate how confused pilots would be from computer responses they intended.  One example concerned the stall warning system.

The angle the wing makes with the air is called the angle of attack, AOA.  You can think of it as the angle the wing makes with the direction of travel in the air.  Roughly, wings generate lift that is proportional to the AOA, up to a critical AOA.  Beyond the critical AOA, the airflow over the wing becomes turbulent and the lift is enormously reduced, resulting in a descent in an unstable condition.  This regime is called a stall - the wing is stalled.

The AOA control in an airplane is the stick.  Pulling it back increases the AOA and pushing it forward decreases the AOA.  Thus, the pilot will induce a stall if he holds the stick too far back.  To avoid unanticipated stalls, airliners have what is called a stick shaker and/or stick pusher, along with a computer generated voice that says "stall" or something equivalent.  These safety features operate when the computer senses too high an AOA.

The Air France 447 computer system had these safeguards.  However, the warnings were programmed to stop if the sensed AOA was way too high.  This  reflected the system designers' thinking that such a high AOA indication was more likely due to a system failure than an actual AOA that high.

So, as the pilots pulled back on the stick, they got a stall warning, but due to the weather, the wing went to a way higher AOA and the warning stopped and they no longer thought they were stalled - but they were.  They rode the stall all the way down to the Atlantic, never realizing the problem with the aircraft's responses was that it was stalled.

Wednesday, August 19, 2015

Coffee Intake, Recurrence, and Mortality in Stage III Colon Cancer: Results From CALGB 89803 (Alliance)

Here is a link to an article about coffee and colon cancer in the Journal of Clinical Oncology.  The article's conclusion reads:

Higher coffee intake may be associated with significantly reduced cancer recurrence and death in patients with stage III colon cancer.

The abstract suggests that the "may be" may be "may not be". :-)

Here is the abstract.

Observational studies have demonstrated increased colon cancer recurrence in states of relative hyperinsulinemia, including sedentary lifestyle, obesity, and increased dietary glycemic load. Greater coffee consumption has been associated with decreased risk of type 2 diabetes and increased insulin sensitivity. The effect of coffee on colon cancer recurrence and survival is unknown.

Patients and Methods
During and 6 months after adjuvant chemotherapy, 953 patients with stage III colon cancer prospectively reported dietary intake of caffeinated coffee, decaffeinated coffee, and nonherbal tea, as well as 128 other items. We examined the influence of coffee, nonherbal tea, and caffeine on cancer recurrence and mortality using Cox proportional hazards regression.

Patients consuming 4 cups/d or more of total coffee experienced an adjusted hazard ratio (HR) for colon cancer recurrence or mortality of 0.58 (95% CI, 0.34 to 0.99), compared with never drinkers (Ptrend = .002). Patients consuming 4 cups/d or more of caffeinated coffee experienced significantly reduced cancer recurrence or mortality risk compared with abstainers (HR, 0.48; 95% CI, 0.25 to 0.91; Ptrend = .002), and increasing caffeine intake also conferred a significant reduction in cancer recurrence or mortality (HR, 0.66 across extreme quintiles; 95% CI, 0.47 to 0.93; Ptrend = .006). Nonherbal tea and decaffeinated coffee were not associated with patient outcome. The association of total coffee intake with improved outcomes seemed consistent across other predictors of cancer recurrence and mortality.

Higher coffee intake may be associated with significantly reduced cancer recurrence and death in patients with stage III colon cancer.

Here are some reasons that strike me as justifying skepticism.

The study is a prospective study with no controls.  It is possible that patients who are doing the best and feeling the best drink more coffee.  In that case the causality runs from health to coffee, not from coffee to health.

131 items were examined for a possible relationship.  In a 131 variable regression, the probability that at least one variable will have a statistically significant estimated relationship with the dependent variable is high, even if the there is really no relationship between any of the 131 independent variables and the dependent variable.  The study quotes measures of statistical significance that appear to be unadjusted for this.  If so, they are wildly overstated.

Tuesday, August 18, 2015

Fraudulent study in the American Journal of Public Health inaccurately claims that states with more guns have more police deaths

Here is a link to a critique of an American Journal of Public Health paper that claimed that states with more guns have more police deaths.

The authors note that the AJPH paper uses faulty statistics, and that the correlation is reversed if better statistics are used.

Stuart Anderson: Trump The Hypocrite: Investing Overseas Fine For Him

Here is a link to Anderson's column in Forbes.

Anderson is right.

A lot of what Trump says about international trade is ridiculous, and he does the things he berates others for doing.  It is not that he and others are doing something bad, it is that they are doing something good and Trump is calling it bad.

Sunday, August 16, 2015

John Cochrane: The wrong austerity

Here is a comment from John Cochrane about the Greek version of "austerity".  The message is that Government is dysfunctional again.

A barrage of new tax measures are contained in the new bill presented to Greece’s Parliament

...diesel fuel tax for farmers going from 66 euros per 1,000 liters to 200 euros/1,000 liters from October 1, 2015, and to 330 euros by October 1, 2016. Farmers’ income tax to be paid in advance will rise from 27.5 percent to 55 percent. Income tax for farmers is set to rise from 13 to 20 percent for 2016 and to 26 percent for 2017.

Freelancers will be subject to a gradual increase from 55 to 75 percent in advanced tax payments for income earned in 2015, increasing to 100 percent in 2016. The 2 percent tax break for single payments on income tax is also being abolished from January 1, 2015.

Private education, previously untaxed, will be taxed at 23 percent, including the tutoring schools (frontistiria) that most Greeks send their children to but excluding preschools.

Greece’s vital shipping industry will also be subject to new tax rises. Among other measures, tonnage tax is to increase by 4 percent annually between 2016 and 2020. A special contribution by foreign cargo carriers will remain in place until 2019.

"Austerity" has been a contentious and vague word, descending to an all-purpose insult from the pen of Krugman et al.

But on one point I think we can agree. Steep tax increases, especially steep increases in marginal tax rates on people likely to work, save, invest, start new businesses, and hire others, are an especially bad idea right now. The only hope to pay back debt is growth, and this sort of thing just kills growth. Part of growth is also keeping smart young Greeks in the country, which they are leaving in droves.

Sure, I look at the margins,  incentives, and "supply," while Keynesians look at taxes as just "money in pockets" that drives consumer spending and "demand."  But looked at either way, this is really counterproductive.

In practical terms, there is a Laffer curve, whether of supply side incentives or demand side multipliers. And for paying back debts, the long-run Laffer curve matters:  the effect of taxes on business formation, expansion and growth; on people moving to and from a country. The contentious short-run Laffer curve is on the question whether people with jobs work fewer hours at high taxes. Maybe yes, maybe no, but that's not the issue for Greece or for her creditors.

I think the Europeans think they can just raise tax rates and produce more interest payments. Alas, you have to let a garden grow before you harvest the fruit.

The Economist: Do we live in a multiverse?

Here is a link to a video at The Economist.

Run the video "Do we live in a multiverse".

I'm betting on a multiverse.  Hmm, how will I know if I win? :-)

George Will: America’s barnacled budget

Here is a link to an article by George Will.

Will explains how and why minorities make the Federal Budget a painful joke for majorities.  However, he does not go quite far enough.

Assume, for simplicity, equal distribution of cost.

If a minority, say 1% of the populace gets the Government to pay it $1.00, it costs the minority  only $0.01.  Thus, there is an incentive for minorities to try to get Government handouts.

If the populace is composed of 100 minorities, then each has an incentive to get its $1.00 at a perceived cost of $0.01.  However, if each is successful at perverting the Government Budget in this way, all of the minorities will receive $1.00 each and will pay $1.00 each.  Actually, the cost will exceed $1.00 each, as there are costs to run the various programs.

All this waste could be avoided if all the minorities agreed not to receive Government handouts.  However, there is no way to obtain and enforce such an agreement.

Put yourself in the position of one of these minorities (probably, you are knowingly or unknowingly already a member of several).  Would you agree to refuse your handout?  Of course not - there is no credible evidence that everyone else would, so if you did, you would simply be a loser.

Obscure Engineering Conversions Factors

Ratio of an igloo's circumference to its diameter = Eskimo Pi

2000 pounds of Chinese Soup = Won ton

1 millionth of a mouthwash = 1 microscope

Time between slipping on a peel and smacking the pavement = 1 bananosecond

Weight an evangelist carries with God = 1 billigram

Time it takes to sail 220 yards at 1 nautical mile per hour = Knotfurlong

365.25 days of drinking low-calorie beer = 1 Lite year

16.5 feet in the Twilight Zone = 1 Rod Serling

Half a large intestine = 1 semicolon

1,000,000 aches = 1 megahurtz

Basic unit of laryngitis = 1 hoarsepower

1 kilogram of falling figs = 1 Fig Newton

1000 ccs of wet socks = 1 literhosen

Thursday, August 13, 2015

John Lott: The New York Times Believes MoJo’s Gun-Control Myths

Here is a link to an article by John Lott critiquing a New York Times article about allowing law abiding citizens to carry concealed guns.

The New York Times shows its ignorance and incompetent journalism, as Lott points out.

George Will: The man who helped kill the Soviet Union with information

Here is a link to a very good article by George Will.

It relates how the printed word can help defeat dictators.

His comment about Bernie Sanders is on target.

Read it.

Tuesday, August 11, 2015

My only published "poetry"

Published in the August 1980 issue of "Soaring".

Soaring along a wooded ridge, I meet a hawk
            Aloft like me on the Autumn breeze.
We linger, he and I, amidst the colors
            And the whisper of the wind
Until, as dusk rises from below,
            We fall gently back to earth.
Feeling all the while,
            The pulse of life within us.

Sunday, August 09, 2015

A Tale of Johnny and Tommy

Here is a link to a comment by Don Boudreaux that is on target.

Anti-social behavior that would not be tolerated by children or by adults acting as individual  is lauded by progressives in politicians.

Friday, August 07, 2015

What Democrats get wrong about the middle class

Here is a link to an article by James Pethokoukis at the American Enterprise Institute.

JP points out some of the reasons why the middle class is really much better off now than it was two to three decades ago.

Wednesday, August 05, 2015

John Lott: What Mother Jones Missed In Its Hit Piece About Me

Here is a link to an article by John Lott that illustrates the despicable tactics of the anti-gunners.

Lott is on target, it is worse than he portrays.

The best book on the impact of concealed carry and related laws on crime rates is Lott's "More Guns Less Crime".  It provides all the common sense, statistics, and description about the level of discourse by anti-gunners that you need.  On top of that, it is a great read.

You can get Lott's book here.

How Not to Pass a Carbon Tax

Greg Mankiw makes some good points about how political reality can prevent implementing good economics.

Here is the link.

Mankiw makes the point that, in principle, a carbon tax can be sensible.  He notes that one problem with implementing one is that the revenue is likely to be used to increase Government, rather than to reduce other taxes, hence a reason for many to oppose a carbon tax.  Mankiw fails to mention two other key problems - (1) how is one to one to know what is the right tax level and (2) that there are political motives to make the tax larger - much larger - than optimal, even if the optimum tax level is known.