Saturday, August 17, 2019

Sorrow for the Long Tail - the memory machine I will never see

There are several software products I want nobody will build.

For example, I want a “screen saver” that will randomly select from a collection of video and still images and display them across multiple screens.

Pretty much like Apple’s annoying [1] screen saver, but for video it would randomly select a xx second file segment and play that without sound.

I don’t think anyone will ever build this. It’s too hard to do [2] and there’s no money in it. Only a small number of people would pay, say, $20 for this. Maybe 1 in a 1000. After expenses and marketing it would be hard to earn even a few thousand dollars.

Which reminds us of the false promise of The Long Tail. Those were the days that Netflix had a huge catalogue of barely viewed movies [3] that were often very fine. We thought there would be business for the interests of the 0.1%. That didn’t happen.

This is why I’ve given up on trying to predict the future ...

--

[1] Whenever macOS cannot connect to the folder hosted on my NAS it reverts to the default collection. I need to restore my share and I’ve never been able to find an automated way to do that. On iOS things are much worse. Speaking of products I want, I’d pay $20 for a macOS utility that that simply reset my screen saver to my preferred share.

[2] We never thought software development would keep getting harder. We used to think there would be a set of composable tools we could all use (OpenDoc, AppleScript, etc). We expected a much more advanced version of what we had on DOS or Unix in the 80s or the early 90s web. Instead we got AngularJS.

[3] In the mailer days our kids movies were unplayable due to disc damage about half the time. Finally gave up on that.

Monday, August 12, 2019

Rough personal notes on review of management of degenerative lumbar spondylolisthesis with lumbar spinal stenosis and pseudoclaudiation

Every so often I review a medical topic and stick my notes into Simplenote for later reference. The reviews are quite messy since it’s just for my use. For what it’s worth, some hasty notes on this topic.

IMAGING

Initial Plain film: spondylolysis/listhesis. Standing flexion/extension lateral plain film, oblique (for pars interarticularis), AP for severity. (or just lateral, oblique and AP). See https://emedicine.medscape.com/article/2179163-workup

Considering surgery: MRI (neurosurgeon will have preferences)

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2270383/
Degenerative spondylolisthesis - European perspective - 2008

“Symptoms of neurogenic claudication that cause the patient to stop and sit after less than two blocks of walking usually correspond to the time, when the patient consents to surgery …

…. The plain radiographic features include the essential finding on a lateral view of forward displacement of L4 on L5 or, more rarely, L5 on S1 or L3 on L4 in the presence of an intact neural arch. Defect of pars interarticularis (which has the appearance of a Scottie dog with a collar) that can be seen on lateral or bilateral oblique views helps to distinguish between DS and isthmic spondylolisthesis …

… Only 10–15% of patients seeking treatment eventually will have surgery…

… The intervertebral spaces of the slipped segments were decreased significantly in size during follow-up examination in patients in whom no progression was found. LBP improved following a decrease in the total intervertebral space size. The development of osteoarthritic spurs, hypertrophy and ossification of the intervertebral ligaments, and facet arthrosis may lead to secondary stabilization that prevents slip progression…

Indications for surgery:
1. Persistent or recurrent back and/or leg pain or neurogenic claudication, with significant reduction of quality of life, despite a reasonable trial of non-operative treatment (a minimum of 3 months).
2. Progressive neurological deficit.
3. Bladder or bowel symptoms.

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6357993/ (2019 review, neurosurgery)
A systematic review of the literature has shown that delaying surgery for a period of conservative management is not associated with a worse surgical outcome and that surgery is more effective than continued conservative treatment when conservative options have failed for a period of three to six months…
… minimally invasive surgical approaches that preserve stabilizing paraspinal musculature …

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Some other odds and ends:

- We suggest that the angular instability of the intervertebral disc may play a more important role than neurological compression in the pathogenesis of disability in degenerative lumbar spondylolisthesis (this was weird — from MRI study of axial loading)

- Vanderbilt neurosurgery study from 2014 claimed medical management didn’t work but it looked like a horrible study

- BMJ review of 2016 was down on non-surgical treatment but not super keen on surgical. Consistent with trying conservative management for some time before trying surgery.

Tuesday, August 06, 2019

Warmer climate on the earth may be due to more carbon dioxide in the air. 1956.

Originally published in the NYT Oct 28, 1956 by Waldemar Kaempffert. Reprinted as Climate Science in 1956 and 2015 | HuffPost:

The general warming of the climate that has occurred in the last 60 years has been variously explained. Among the explanations are fluctuations in the amount of energy received from the sun, changes in the amount of volcanic dust in the atmosphere and variations in the average elevation of the continents.

According to a theory which was held half a century ago, variations in the atmosphere’s carbon dioxide can account for climatic change. The theory was generally dismissed as inadequate. Dr. Gilbert Plass re-examines it in a paper which he publishes in the American Scientist and in which he summarizes conclusions that he reached after a study made with the support of the Office of Naval Research. To him the carbon dioxide theory stands up, though it may take another century of observation and measurement of temperature to confirm it….

…. The atmosphere acts like the glass of a greenhouse. Solar radiation passes through to the earth readily enough, but the heat radiated by the earth is at least partly held back. That is why the earth’s surface is relatively warm. Carbon dioxide, water vapor and ozone all check radiation of heat.

Of the three gases that check radiation, carbon dioxide is especially important even though the atmosphere contains only 0.03 percent of it by volume. As the amount of carbon dioxide increases, the earth’s heat is more effectively trapped, so that the temperature rises.

... According to Dr. Plass, the latest calculations indicate that if the carbon dioxide content of the earth were doubled the surface temperature would rise 3.6° C and that if the amount were reduced by half the surface temperature would fall 3.8° C...

...Despite nature’s way of maintaining the balance of gases the amount of carbon dioxide in the atmosphere is being artificially increased as we burn coal, oil and wood for industrial purposes. This was first pointed out by Dr. G. S. Callendar about seven years ago. Dr. Plass develops the implications….

… Today more carbon dioxide is being generated by man’s technological processes than by volcanoes, geysers and hot springs. Every century man is increasing the carbon dioxide content of the atmosphere by 30 percent — that is, at the rate of 1.1° C in a century. It may be chance coincidence that the average temperature of the world since 1900 has risen by about this rate. But the possibility that man had a hand in the rise cannot be ignored.

Whenever the cause of the warming of the earth may be there is no doubt in Dr. Plass’ mind that we must reckon with more and more industrially generated carbon dioxide. “In a few centuries,” he warns, “the amount of carbon dioxide released into the atmosphere will be so large that it will have a profound effect on our climate.”

Even if our coal and oil reserves will be used up in 1,000 years, seventeen times the present amount of carbon dioxide in the atmosphere must be reckoned with. The introduction of nuclear energy will not make much difference. Coal and oil are still plentiful and cheap in many parts of the world, and there’s every reason to believe that both will be consumed by industry as long as it pays to do so.

I believe current predictions are on the order of 2C with doubling CO2 with longer term higher secondary increases. So bit less than 1956 model, but on the other hand the effects on climate have been obvious sooner than expected.

Overall, holds up quite well.

Monday, August 05, 2019

The rules change

On the 9th of August 2009 I wrote a post on at the start of my 51st year. It included an estimate that I was at "70% lifetime strength”. That was an improvement over June of 2008.

I figured it was downhill from there.

I was wrong though. Four years later, in April of 2013, I started doing CrossFit. It’s enlightening to look back at what I wrote then:

… I now do CrossFit twice a week; that's about as much as I have been able to safely handle. I currently need 3 days to heal between each session. Between sessions I do my usual 2 hours of bike commuting one day a week...

...After five months, despite my back strain injury, St Paul CrossFit has worked well for me. I haven't developed much visible muscle, but I'm significantly stronger and I can handle more exertion. My weight didn't decrease until about month 4, since then I dropped 8 lbs and am close to my optimal weight.

The net effect is that physically I perform and feel more like I did at 44 than at 54. That's a big difference; if I feel at 62 the way I was at 52 I'll be content.

I'm not as keen on CrossFit as some but I enjoy the people, the exercise, and the game of staying within my limits … I'll probably go to three times a week when ice and snow stop my bicycle commute...

… At 54 I'm into managed-decline rather than improvement, but at 34 I'd have been tempted. CrossFit workouts are intense -- and I'm not sure five or even four workouts a week makes sense for most 35+ bodies…

Six years later I would frequently do CrossFit five times a week, and I usually managed four times a week. At age 59, six years after starting, I amazed myself by surviving a 300 lb deadlift. That’s warmup weight for a strong middle-aged man, but it was a lot for me.

I got my dubs last year.

I've had several weight lifting and gymnastic personal records in the past two years. “Managed decline” didn’t happen at 54 after all -- despite being hit by the familial arthritis train at age 56. In retrospect, while my physiologic maximums had been declining for decades, there was more head room than I’d expected. I just started living closer to that maximum performance level.

But we know how the story ends. We know what 85 looks like. There’s a steep descent ahead.

I think I’ve started that run. Over the past few months I’ve been more fragile, prone to old injury patterns, healing more slowly. I didn’t make my 8/1/ Bar Muscle Up goal (still training though).

My peak performance has met my downward trending physiologic limit.

They probably met in May of 2019 - 3 months ago, but I only got the message last week when a minor back strain passed all my usual fitness tests — and got suddenly worse on a warmup lift. The rules changed.

I greeted this understanding with the mature wisdom of an Old person.

Hah, hah. Not really. I wanted to cry. I was crying on the inside. For a day or two anyway.

Now I have to figure out the new rules. I’m off CrossFit until after my early September Maah Daah Hey mountain bike trail ride — I need to be as rehabbed as possible until I’ve done that trip. So I’m doing my training rides, my rehab weight lifting (my strict pull-ups are 50% improved, also working on a new bench PR!), started swimming again, picking up more inline skating.

I’m studying my Supple Leopard book.

When I return to CrossFit (9/9/2019 is the plan) I can max on the cardio and the body weight reps and I can keep training for my maybe-never-bar-muscle-up, but it will be months before I let myself do serious weights. I have to figure out the new rules.

Maybe next year I’ll do my first triathlon.