Friday, March 27, 2020

Tabclearing Day

Tof has been remiss in keeping Faithful Reader up to date on all the things that FaithfDul Reader craves updating.

1. Phone Alone. 

In 1910, the WaPo discovered cell phones. Well, walkie-talkies, actually. These would enable shy lovers, as WaPo imagined, to call their beloved and confess their love without embarrassment..
Wireless Telephones

 2. Don't Forget Your Epi

Epigenetics means that one organism's learnings could be inherited by its offspring.IOW, it's not all Darwinian natural selection.

3.  Lamarck's Revenge

Speaking of epigenetics... Unified Theory of Evolution

 4. If We Can Send a Man to the Moon...

...why can;t we send a man to the moon? We no longer have the skill sets that sent Apollo out. We'd be starting from scratch if we tried. Back to the Moon!

 5. Arbitrium Liberum

Aquinas always said 'free judgement,' not 'free will.' The fMRI argument is full of crap.
Free Will

 6. What's New?

A mathematical study of innovation. Not everything imaginable is possible; and not everything possible is probable. Innovations work when they are "adjacent" to the AS IS situation. Let's have airplanes without propellers! Let's have radios with pictures! The Adjacent Possible.

7. "Knock, Knock! Who's There?" -- Macbeth, Act II, Scene III

Surprising what Shakespeare said back in the day. Shakespeare Quotes

Wednesday, March 25, 2020

The Wuhan Coronavirus

This morning's (3/25) reports from the five hardest hit provinces in China

Place cases recov'd deaths active
  1. Hubei 67,801 60,811 3161 3827
  2. Guangdong 1,433 1,336 8 89
  3. Henan 1,274 1,250 22 2
  4. Zhejiang 1,241 1,221 1 19
  5. Hunan 1,018 1,014 4 0
The death RATES can be bracketed by assuming all pending cases die or that all pending cases recover, both being less likely than that some do and some don't.
  1. Hubei 4.7% 4.9% 10.3%
  2. Guangdong 0.6% 0.6% 6.8%
  3. Henan 1.7% 1.7% 1.9%
  4. Zhejiang 0.1% 0.1% 1.6%
  5. Hunan 0.4% 0.4% 0.4%
So, unless a whole bunch of new cases appear -- and the meejah are doing their best to raise this possibility -- the Wuhan epicenter (Hubei province) will probably run about 5% mortality. Probably because the govt there at first tried to conceal it and only took action after it was 'too big to fail.' None of the other high-case provinces touch this. Only neighboring Henan comes close, at just under 2%. Guangdong is currently at 0.6% and only if every pending case is mortal might it become as high as 6.8%. In Hunan, where all cases are resolved at this point, the mortality is less than half a percent.

Thursday, March 12, 2020

The Dreaded Red Squamish

As an aid to another discussion elsewhere regarding the latest pandemic, consider the effect of screening for the Dreaded Red Squamish of which, unbeknownst even to Health Care Professionals, infects 5% of the population.

The test, which includes the person administering it, the instruments, conditions, and all what have you, is known to be 95% sensitive -- of those with the Squamish, the test will come back positive 95% of the time -- and 95% specific -- of those without the Squamish, the test will come back negative 95% of the time.

Perceptive Reader will notice that this means a 5% risk of a false positive and a 5% risk of a false negative. The Usual Suspects may cry, "No fair!" because they want Daddy and Mommy to ensure 100% perfect. [When do we want it? Now!] But the sensitivity is about normal for lab tests while the specificity is actually better than normal. (As an example of lack of specificity is the well-known ability of drug testing to detect the consumption of poppy seed bagels.) It is also hard to imagine that the 15,000th test will be performed with the same sprightly verve and enthusiasm as the 1st.

Now, test a million people for the Red Squamish, just in case.
 Of the 950,000 folks who are not infected. nearly all (95%) get a clean bill of health and of the 50,000 infected souls, nearly all (95%) get a red card. But along the way 2500 infected people go undetected, while 47,000 uninfected get red carded nonetheless. Perhaps they ate a poppy seed bagel that morning, or the test was run late at night by a dog-tired technician. In any case, you will notice that half of all those getting flagged are not in fact infected.

Consequently, the media reports that the infection rate is 9.5% [(47,500+47,500)/1,000,000] rather than 5%, although what they really mean is that the test-positive rate is 9.5%. 
This also affects estimates of the mortality rates. It's not called the Dreaded Red Squamish for nothing. But the denominator has been inflated by the false positives, so deaths will be divided by 95,000 rather than the [unknown] 50,000. There will be 47,000 "recoveries" of people who never actually had the disease. OTOH, some of the undetected 2,500 may also shuffle off the coil of mortality, but these will be assigned to collateral conditions (heart disease, asthma, etc.)

Those unfamiliar with the exigencies of measurement systems analysis are too likely to take test results as given.
Type I and Type II errors are universal. They apply to any decision process. In law, Type I is convicting the innocent and Type II is freeing the guilty. In the FDA, they are (I) withholding approval from a safe and effective medical device or (II) approving an unsafe or inneffective medical device. In product inspection you can (I) approve defective product or (II) reject conforming product. You can decide (I) not to kiss a willing girl or (II) to kiss an unwilling one.
What differs among these cases and others are the consequences of the errors. We try to avoid Type I error in trials and sending innocent people to jail; but we would rather avoid Type II error in FDA approvals. In the latter case, if we approve a device that turns out to be unsafe, people may die. People may also die if a safe and effective device is withheld from the market -- but they don't die on the front page. 
You can't improve by making the decision rule more stringent. That will only shift the errors between I and II. It's like Whack-a-Mole. Drive down one type of error and you'll drive up the other. You have to change the decision rules themselves.

Of course, none of this means the Dreaded Red Squamish is not dreadful. It only means the numbers may lead to unreasonable panic or to complacency. 
Or both.

Monday, March 9, 2020

One Flu Over

This is an excerpt from "Places Where the Roads Don't Go," which appeared in the collection Captive Dreams.

One Flu Over

It was five years later, during the big epidemic, when everyone went about wearing those face-masks and getting their shots, when we all met again.  Jared had contracted the flu and had fallen deathly ill.  And while he was not as close to me as he was to Kyle, still he had dated my sister and we knew each other better than most.  

The worst of it was over by then and the airports were open once more, so I caught a regional to Newark, rented a car, and drove down to Princeton Hospital.  Traffic was light and people still tended to avoid one another.  Like soldiers in the waning days of a war, those lucky enough to have escaped so far had no desire to become the last fatality.  It was, sadly, the smoothest trip that anyone had ever taken down the Jersey Turnpike.  

The University Medical Center stood on a side street, past an old cemetery, which struck me as bad feng shui for a hospital.  I drove through to the parking lot and walked back to the main building.  It was a chilly, blustery spring quite in keeping with the mood of the country.  The information desk was enclosed within a Plexiglas shell under positive air pressure so germs would not waft into the booth.  I presented my certificate of inoculation and passed through the sanitizing airlock into the main hospital.  The UV lamps, air jets, and gas spray were supposed to sterilize visitors, but I thought they might be only to reassure them.  It certainly cut down on the number of visitors. 

New Story from Michael F. Flynn

 Greetings All.    Mike (Dad) has a new story in the July/August edition of Analog . I know Analog is available on Kindle store and Analog ...