Category Archives: natural-world

Sleeper cells

I’ve recently been enjoying a podcast on microbiology.

They recently mentioned that some bacterial infections include a tiny fraction of hibernating cells.   The sleepers are unaffected if somebody tries to murder with an antibiotic.  Later when they awaken the antibiotic is gone and the infection returns.

Bad faddish ideas are like this too.

Narwhale distribution

Amusing neologism: the narwhale distribution.  i.e. the statistical distribution with a horn.


That’s taken from a lovely essay in “Small Things Considered” about how some viruses operate in two modes.  In the mode your probably familiar with they infect the cell, repurpose things to reproduce, and the blow up the cell to go in search of more prey.  But in another mode they are more like a parasite.  It seems that when in this second mode they can provide a benefit to the cell, i.e. a defense against the first mode.  Oh nature!

Smeed’s Law

In the 1930s a traffic engineer in England noticed a curious pattern in the data about highway deaths.  Here is the chart from the article he published.

The vertical axis shows deaths/car and the horizontal shows cars/person with one dot for each country.  That’s for 1938.   In 1938 few people in Spain(19) owned a car, but those that did were causing a lot of deaths.   Switzerland(2) wasn’t fitting the model very well.   You can make up your own insta-theory for why countries with few cars/person kill more people with each car.

Here’s a chart from 1980.  More countries, more years, more confirmation of the model.  The data are shown twice, the second time is a log-log graph.

Note that there are lots of things you might think would affect the numbers for a given country.  For example: seat belts, population density, driver median age, safety regulations, insurance, policing, road quality, dash-board cams…  But those aren’t part of this simple curve and so can only effect the residuals.

I stole these charts from J.G.U. Adams short article “Smeed’s Law: some further thoughts” in Traffic Engineering and Control, 1987

I find this all weird.   You would think the traffic engineers would have a polished consensus by now of what this is saying.  Adams’ article has some interesting things to say.  For example societies learn to manage the cars as their numbers increase.   But I don’t sense there is a consensus in the profession.  Even now, 80+ years after the pattern was first noticed.

Northwestern United States – Earthquake

Once upon a time geologists believed that, unlike California, the Pacific Northwest was pretty stable.  Earthquakes?  Not to worry.  Other than a few Native American folktales, it’s been quiet since settlers showed up.

But, I’m reading “Cascadia’s Fault: The Earthquake and Tsunami That Could Devastate North America” (library, amazonblog) which explains how they came to change their minds about that.

Now they think that something pretty horrific is in the cards.  If you can sublimate what that means it’s a very cool detective story.  I particularly like that they know exactly when the last monster quake occurred: 9pm on January 27th, 1700.  They know this because of extensive written records of the Tsunami it caused hitting the coast of Japan.  They know this because they found trees still standing in salt marshes, killed when the ground sank and the saltwater killed them.  They pulled the well preserved roots from under the mud and counted the rings.

They have core samples of the off shore mudslides that the monster quakes have created.  Using techniques from the oil industry they can match up the wiggles in the core samples taken from these samples they can puzzle out a history for these monster quakes that goes back a long way.  They can draw a sobering timeline (click to enlarge).



They know the mountain tops are slowly squeezing together.  These days they can watch the mountains of the entire region move, every day.  They can sum up how much stress has accumulated.  Around 60 feet of slippage will be unwound by the next quake.  The big ones on that timeline are magnitude 9.  No city with sky scrapers has have ever experienced that.  The 2011 Japanese Tsunami was triggered by a one.

So, the state of Washington has a brochure.   It suggests that most every bridge in the state will collapse.

ps. Mimi and I will be in San Francisco the last weekend of July; for the Renegade Craft fair.

Big Warm Blooded Animals

This is a lovely simple article: How Large Should Whales Be?  It’s a simple article because it builds on an earlier article about the sizes of land mammals.

The model in the article rests on some stylized facts about animal size. Fossils show that over time species tends to get larger; we can presume there is a benefit to being larger.  Warm blooded animals have a minimun size; if your tiny it’s hard to keep warm. Most warm blooded animals are about the size of a large rat (or squirrel).  Which doesn’t really make sense since we already said that larger is better.

The tension between the advantages of size and the fact that most warm blooded animals aren’t huge is – they say – about extinction. On the one hand it takes time to evolve into something huge and on the other hand the speicies is always at some risk of going extinct. This is almost enough to build a model that explains the distirbution of sizes for warm blooded animals. We need only one more detail – i.e. that larger animals are more likely to go extinct. I gather the model works extremely well.


The paper just extends the model from land to sea. Showing that the model works very nicely for whales and such. It’s harder to keep warm in the water, so the minimum size for a aquatic mammal is larger than that of a land mammal. My favorite factoid from the paper is that land mammals moved into the water as soon as grew larger than the warmblooded aquatic minimum.

Why are larger species are more likely to go extinct? It’s bit counter intuitive. Size has a short term advantage, otherwise they wouldn’t evolve toward larger sizes.  A large animal has, in effect, a larger bank account and that let’s him buffer life’s vicissitudes.  But why would it be good in the short term and bad in the long term.  A possible logic is that any species resides in some niche, and it’s a bigger then you get a smaller population filling the niche. Small populations are easier to wipe out.

I don’t really see any hope that this model is useful in other contexts closer to my interests: firm size, wealth distributions, city size, etc.  Their size distributions don’t look like that illustration, not at all.  They have much longer tails to the right.  Suggesting the extinction events are rare for them.  But it’s an amusing exercise to try. Look for the analogies to theromodynamics, evolution, and extinction events.

Forgetting to succeed

I learn from a book that bacteria are unlike life as we know it.  The evolutionary mechanisms are different.  Food scarcity is the primary pressure on them.  When food is scarce reproducing fast is beneficial.  The book mentions two ways the accelerate their reproduction. Both address the same problem copying the genetic material takes time.  First off they shed genes.  For example they will very quickly shed the genes for antibiotic resistance when the antibiotic is absent.  Secondly; recalling that bacteria are a-sexual.  That allows mom a head start.  She can make the copy that will be used by her grand daughters.

The shedding genes appears, at first glance, to be very short sighted.  My house is full of stuff I’m not going to need tomorrow; but yeah I retain to insure against the possibility I’ll need it next week.  The bacteria have stumbled on solution to this problem, they steal genes from each other.  In fact they do it a lot, the percentages are huge.  I think this is amazingly cool.  The community can, and will, shed the gene for antibiotic resistance quickly; but if only a handful of the community retain it then the community can survive the reintroduction.  I do that too.  I discard stuff in my house because I know I can recover it from the city around me.

Much fun can be had with this.  For example here is a fun essay on the evolutionary history of the directories in my Unix PATH.  At each point in time it seemed like a good idea, solved a problem; but now we carry the complexity around.  The essay is written by somebody who is under very different evolutionary pressures; so he’s trying to shed those genes.

I’m reminded of how the 1984 macintosh shed the genes for memory management, because it wanted to reproduce more quickly than the Lisa.  Getting that gene back wasn’t easy, but the design pattern certainly didn’t get lost.

The dialectic between reproducing fast and remembering and copying all the important design patterns is a key challenge in any new product.  It is the curse of experience that you have a deeper catalog of design patterns you feel you must decide if you will or won’t pack them into today’s new product.  I’m always a bit bemused by how casually presumptive some people are about the absolute necessity of packing in this or that thing.  For example: first customer contact v.s. QA?  For example: delivery or modularity?  For example: features or cross platform.

The answer tends to fall out of the R-selected v.s. K-selected nature of your business ecology.  It’s part of what makes small businesses radically different from big ones.  Which reminds me of who eats the bacteria.

So in this amusing game of analogy what plays the role of antibiotic.  QA is a kind of antibiotic, but I think a better example would be the skills that organizations need to have to defend themselves from the dark arts – i.e. the agents that immunize the organization against the numerous bad ideas found in the business cults.

And then finally, let’s says something about how the bacteria draw upon their community much as I draw upon the city around me.  In a business context I think that explains a lot about the survival value that comes from situating your small business inside a geographic region  or virtual community from which you can draw in the craft knowledge you’ll probably shed in exchange for fast growth out of the box.

lawyer’s wig

Encountered this beautiful stand of fresh shaggy ink cap mushrooms today:

I don’t believe I’ve every eaten these, though they are reported to be very tasty, but you need to act fast.  They liquify into a black ink within hours of picking them. Their spores are  distribute in the ink.  I like the story that some collectors carry a pan with them so they can eat them immediately.

Note: there is another common ink cap that’s poisonous.