Shared posts

10 Jan 23:28

The dawn of mediocre computing.

by mdbownds@wisc.edu (Deric Bownds)

This post is a followup on MindBlog's 12/07/22 post on OpenAI's ChatGPT essay generating system. It was mentioned in Venkatesh Rao's essay "The Dawn of Mediocre Computing" that my techie son, Jonathan Bownds,sent to me. After pasting in the first two paragraphs of Rao's article, I want to pass on some essential clips that Jon extracted from Rao's overly long text, the sort of logorrheic writing that is responsible for the TLDR (too long didn't read) acronym. 

Well, we all knew it was coming. Computers already easily overwhelm the best humans at chess and Go. Now they have done something far harder: achieved parity with David Brooks at writing.
OpenAI’s ChatGPT, released as a research beta two days ago, has done to the standard high-school essay what cameras did to photorealistic painting and pocket calculators did to basic arithmetic. It is open sign-up and free for now, but I suspect not for much longer, so go try it; and make sure to trawl social media for interesting and revealing examples being posted by people.

Definitions:
Mediocre computing is computing that aims for parity with mediocre human performance in a realish domains where notions of excellence are ill-posed.
Excellent computing is computing that aims to surpass the best-performing humans in stylized, closed-world domains where notions of excellence are well-posed.
Most of us spend most of our time in realish domains. The urban built environment, workplaces, shopping, and modern systems of roads are all examples of realish domains. But I want to focus on two big and important ones in particular: language and money. Vast numbers of mediocre humans make good livings producing words and/or moving money around. These activities are also the home domains of the two frontiers of computing today, Al and crypto. The Second and First Foundations of the mediocre future of computing.
Via seemingly unrelated computational pathways, these two realish domains have succumbed to computerized automation. Incompletely, imperfectly, and unreliably, to be sure, but they definitely have succumbed. And in ways that seem conceptually roughly right rather than not even wrong. Large language models (LLMs) are the right way for software to eat language. Blockchains are the right way for software to eat money. And the two together are the right way to eat everything from contracts to code.
This reeks of real yin-yangery that extends to the roots of computing somehow. It's not just me hallucinating patterns where there are none.
I'm not trying to be cute here. I sincerely believe mediocre computing in realish domains is not just harder than excellent computing in stylized domains, but constitutes a whole higher category of hardness. There is an element of Moravec's paradox in my reasoning here. Roughly, the paradox states that tasks that look simple, and which all humans can do, are harder for Als than tasks that look hard, and which seem like exceptional achievements among humans.
10 Jan 23:27

Neurocomputational evidence that conflicting prosocial motives guide distributive justice

by mdbownds@wisc.edu (Deric Bownds)

A fascinating perspective and analysis from Hu et al. who show that three prosocial motives (fairness, harm aversion, and rank reversal aversion) are encoded by separate neural systems, compete for representation in various brain areas processing equality and harm signals, and are integrated in the striatum, which functions as a crucial hub for translating the motives to behavior (see also the commentary by Armstrong and McKee).  

Significance

Resource allocation in human societies usually triggers discussions about fairness, but satisfactory solutions to distribution problems also involve other prosocial motives that may prescribe different actions. Here, we address how the human brain mitigates such conflicts between multiple prosocial motives (fairness, harm aversion, and rank reversal aversion) during wealth distribution. Combining a experimental paradigm with fMRI and integrated neurocomputational modeling, we show that different prosocial motives are separately represented and integrated into choices by neural activity in striatum and its interactions with different brain regions. These findings extend unidimensional economic theories of third-party social preferences, characterize biological bases for individual and contextual differences in resource distribution behavior, and have economic and political implications for the design of taxation policies.
Abstract
In the history of humanity, most conflicts within and between societies have originated from perceived inequality in resource distribution. How humans achieve and maintain distributive justice has therefore been an intensely studied issue. However, most research on the corresponding psychological processes has focused on inequality aversion and has been largely agnostic of other motives that may either align or oppose this behavioral tendency. Here we provide behavioral, computational, and neuroimaging evidence that distribution decisions are guided by three distinct motives—inequality aversion, harm aversion, and rank reversal aversion—that interact with each other and can also deter individuals from pursuing equality. At the neural level, we show that these three motives are encoded by separate neural systems, compete for representation in various brain areas processing equality and harm signals, and are integrated in the striatum, which functions as a crucial hub for translating the motives to behavior. Our findings provide a comprehensive framework for understanding the cognitive and biological processes by which multiple prosocial motives are coordinated in the brain to guide redistribution behaviors. This framework enhances our understanding of the brain mechanisms underlying equality-related behavior, suggests possible neural origins of individual differences in social preferences, and provides a new pathway to understand the cognitive and neural basis of clinical disorders with impaired social functions.
10 Jan 22:59

Thermodynamics as a myth

by tomate

Against all odds I am making long-term plans: I accepted an invitation by my dear friend Aleksandar Ostojic to travel to Serbia next June 14th to discuss about science, philosophy, sociology, anthropology, and all that. Of course I am expert on none of those subjects, but I assumed I could study hard from here to then and get prepared to fluidly discuss Serres, Collins, Viveiros de Castro, CRISPR and just whatever…

Unfortunately, though, I wasn’t aware that, due to urgent bureaucratic deadlines, I had to write an abstract urgently! In panic, I slaughtered the last and most precious of the rabbits from my hat: thermodynamics.

While I do believe I am a (world-renowned?) expert on what “entropy” is all about and on a few other things, still I cannot make sense of whether my boiler is condensing or not. As a theoretical physicist, I feel embarassed whenever an electrician steps into my house.

So to keep myself “on the side of the wheat” (a popular saying in my hometown to mean “safe”), I proposed this:

“Thermodynamics has a special status in physics. On the one hand it is celebrated as a universal theory («the only […] that, within the framework of the applicability of its basic concepts, will never be overthrown», according to a quote attributed to Albert Einstein). On the other hand it is also the most peculiar of physical theories, as 1) its domain of application may vary from the whole universe, to certain machines, to nothing; 2) its “laws” are either mystical («the entropy of the Universe cannot decrease») or technical («it is impossible to devise a machine…»); 3) it is a patchwork of principles and practices and a nightmare for students and teachers; 4) its conception and technical developments are entangled, ever since the industrial revolution.

In this seminar I argue that thermodynamics, despite recent progress in its formalization, is still as confusing as ever: not because of some subtle technical issue, but because it is intrinsically orthogonal to the modus operandi of other purified physical theories that have a well-defined scope. Thermodynamics serves instead as a repository of narratives and myths for scientists to think about their own work from a different angle, dispensing with strict reductionism. Finally I argue that some aspects of these narratives are being appropriated by corporations in the attempt to green-wash their practices, and that other forms of “thermodynamic empowerment” are possible.”

I would love to share these thoughts to anybody nearly interested in going deeper.

09 Jan 20:45

Shared Neural Circuits for Visuospatial Working Memory and Arithmetic in Children and Adults

by Anna A. Matejko
Journal of Cognitive Neuroscience, Ahead of Print.
06 Jan 04:25

Emergent excitability in populations of nonexcitable units

by Marzena Ciszak, Francesco Marino, Alessandro Torcini, and Simona Olmi

Author(s): Marzena Ciszak, Francesco Marino, Alessandro Torcini, and Simona Olmi

Population bursts in a large ensemble of coupled elements result from the interplay between the local excitable properties of the nodes and the global network topology. Here, collective excitability and self-sustained bursting oscillations are shown to spontaneously emerge in globally coupled popula…


[Phys. Rev. E 102, 050201(R)] Published Fri Nov 20, 2020

06 Jan 04:11

The HoTT Game

by Joesph Hua

What is the HoTT Game?

from thehottgameguide.readthedocs.io

The Homotopy Type Theory (HoTT) Game is a project written by mathematicians for mathematicians interested in HoTT and no experience in proof verification, with the aim of introducing cubical agda as a tool for trying out mathematics in HoTT. You can find it here. Much of the content of the game is based on the HoTT book and lectures by Robert Harper on YouTube.

How does the game work?

The game is a guided sequence of exercises that the user can complete in cubical agda. There are currently two main parts to it:

  • Fundamental Group of the Circle: This part has one goal in mind: to show that π₁(S¹) = ℤ from scratch. We use this as an excuse to introduce higher inductive types, univalence, transport, loop spaces, and homotopy levels.
  • Trinitarianism: This introduces the basics of dependent type theory and later the extension to HoTT. We try to outline each new concept with logical, type theoretic, and categorical perspectives. Whilst this can be the starting point for learning HoTT, we recommend users to start with Fundamental Group of the Circle.

The format: The website contains all the information the user needs to play the game, but to follow along with the exercises, one must do so in agda installed on their computer. Unfortunately installing agda is often the most challenging part, and we are yet to find a good solutions to this. If you have any difficulties installing agda, please try to reach us with ‘issues’ on the github repository. If you have any suggestions or solutions (such as making a browser format of the game) please let us know as well.

Who are we and why did we make it?

The current development team consists of Joseph Hua (me), Ken Lee, and Bendit Chan. We are masters students in pure mathematics at Imperial College London. We were inspired by the Natural Numbers Game made by our professor Kevin Buzzard introducing undergraduates to lean, and thought making a similar game would be a nice way to review the HoTT we learnt. Moreover, we thought this would be a nice resource for people to try out HoTT in a modern, hands-on way.

If you try out the game we would also love to hear your feedback.

06 Jan 03:39

Categories and Epidemiology

by john
MathML-enabled post (click for more details).

I gave a talk about my work using category theory to help design software for epidemic modeling:

• Category theory and epidemiology, African Mathematics Seminar, Wednesday November 2, 2022, 3 pm Nairobi time or noon UTC. Organized by Layla Sorkatti and Jared Ongaro.

This talk is a lot less technical than previous ones I’ve given on this subject, which were aimed mainly at category theorists. You can watch it on YouTube.

MathML-enabled post (click for more details).

Here’s the abstract:

Category theory provides a general framework for building models of dynamical systems. We explain this framework and illustrate it with the example of “stock and flow diagrams”. These diagrams are widely used for simulations in epidemiology. Although tools already exist for drawing these diagrams and solving the systems of differential equations they describe, we have created a new software package called StockFlow which uses ideas from category theory to overcome some limitations of existing software. We illustrate this with code in StockFlow that implements a simplified version of a COVID-19 model used in Canada. This is joint work with Xiaoyan Li, Sophie Libkind, Nathaniel Osgood and Evan Patterson.

Check out these papers for more:

For some more mathematical talks on the same subject, go here.

19 Aug 00:20

Shark brain vs. dolphin brain

by Minnesotastan

Via - and to answer your question, dolphin brain vs. human brain.

06 May 02:53

How many martinis is too many ?

by Minnesotastan

In this "immortal quatrain," Dorothy Parker explained that her limit was two:
“I like to have a martini,
Two at the very most.
After three I'm under the table,
After four I'm under my host.” 
I wish we could resurrect Dorothy Parker.  She was a widely quoted author in the 1920s, known for her wit.  A collection of her work was released in the United States in 1944 under the title The Portable Dorothy Parker.  Parker's is one of only three of the Portable series (the other two being William Shakespeare and The Bible) to remain continuously in print."  I'm sure she would have some choice words to offer regarding the current situation in the U.S.  Here are some of her famous quotes:
“If you want to know what God thinks of money, just look at the people he gave it to.”

“This is not a novel to be tossed aside lightly. It should be thrown with great force.”

“What fresh hell is this?”

“Tell him I was too fucking busy-- or vice versa.”

“This wasn't just plain terrible, this was fancy terrible. This was terrible with raisins in it.”

“I had been fed, in my youth, a lot of old wives' tales about the way men would instantly forsake a beautiful woman to flock around a brilliant one. It is but fair to say that, after getting out in the world, I had never seen this happen.”

“So, you're the man who can't spell 'fuck.'" (Dorothy Parker to Norman Mailer after publishers had convinced Mailer to replace the word with a euphemism, 'fug,' in "The Naked and the Dead.”) Addendum: Note this is possibly a misattribution, perhaps said by Tallulah Bankhead (hat tip to reader Michael Skeet).

“Men seldom make passes at girls who wear glasses.”

“The best way to keep children at home is to make the home atmosphere pleasant, and let the air out of the tires.”
For her epitaph, she suggested 'Excuse my dust.'  Ironically "her ashes remained unclaimed in various places, including her attorney Paul O'Dwyer's filing cabinet, for approximately 17 years."  I've requested The Portable Dorothy Parker from the library.

Reposted from 2012 to provide some levity in the midst of pandemic and political news.  I would add, however, that however witty her epigrammatic quotes are, the collected poetry is mostly morose, suitable primarily for an emo book club.

Addendum:  Here's a link for the Dorothy Parker Society.

Addendum:  As reported by NPR:
Dorothy Parker died in 1967 at the age of 73. She left no family and directed that her estate and any future royalties go to a man she had never met but admired, The Reverend Martin Luther King; and on his death, to the NAACP. 
She designated that her friend, the playwright Lillian Hellmann, be her literary executor. But Lillian Hellmann thought that Dr. King was a pompous stuffed shirt, and she didn't think much of the NAACP. 
Seemingly out of spite, [Hellmann] made it difficult for those who wanted to reprint Dorothy Parker's poems or turn her works into plays and movies. 
Marion Meade has written about the saga of Dorothy Parker and Lillian Hellmann in the April-May issue of Book Forum magazine. She joins us from our studios in New York... [continues at the link]

Reposted again to highlight the "What fresh hell is this" sentiment. 

05 Feb 01:46

The next potential horrorshow for our oceans

by Minnesotastan

I started monitoring the internet for articles about deep-sea mining in about 2012, when an article in The Guardian reported that a commercial firm was going to begin mining the seafloor near Papua New Guinea for precious metals.
A "new frontier" in mining is set to be opened up by the underwater extraction of resources from the seabed off the coast of Papua New Guinea, despite vehement objections from environmentalists and local activists.

Canadian firm Nautilus Minerals has been granted a 20-year licence by the PNG government to commence the Solwara 1 project, the world's first commercial deep sea mining operation.

Nautilus will mine an area 1.6km beneath the Bismarck Sea, 50km off the coast of the PNG island of New Britain. The ore extracted contains high-grade copper and gold.
The mining company dismissed fears of environmental damage:
"The material is very high grade so you have to mine less in order to get the same amount of metal," said Chris Yeats, a geologist at CSIRO, the Australian government's scientific arm. "At those depths there are bacteria, but there's a cut off at around 1,000m where most fish are, so it should have little impact."

"Unlike a terrestrial mine, you don't have to build infrastructure such as roads and you don't displace people. You chop off one of these venting chimneys and another one will grow back, so it's a little like the mining equivalent of cutting grass."
In 2016 a UK company joined the Canadian one, although that one was going to focus on extinct vents:
Prime minister David Cameron has said such exploits could be worth £40bn to the UK alone and in March, a UK company won a second licence from the International Seabed Authority to prospect in 75,000 sq km of the Pacific...

They will use robot submarines to be the first to drill into extinct vent deposits, using a specially hardened drill to probe 55 metres below the sea bed... A key question is how much the seawater has rusted away the metals deposited by the hot springs that stopped flowing up to 50,000 years ago.

The deposits can be extremely rich in valuable metals, including gold, cobalt, zinc, tellurium and so-called “rare earths”, which are used in many electrical technologies, including smartphones, wind turbines, solar panels and electric cars and in high-strength, lightweight alloys used in aircraft, for example...
There is absolutely no suggestion or enthusiasm from either scientists, or mining companies as far as I know, to go anywhere near the active hydrothermal systems,” said Murton. “They are extraordinarily rich areas of unique species and ecosystems and we wouldn’t do anything to disturb those.” 
The situation was informally summed up by a geology student
This is going to happen, people. The natural resources industry is becoming desperate to find new mineral deposits, as the replacement rate of new discoveries is lagging consumption by a significant margin. Never before has the industry been so desperate to find new projects, which is why multinational miners are more willing than ever to work in the worst of the third-world nations or in formerly frozen terrains that are only now being exposed by global warming...

Seafloor mining is NOT going to be particularly environmentally destructive. Nearly all of the black smokers in question that are going to be mined are geologically dead, having moved too far away from undersea volcanic activity. These deposits are MASSIVE. The potential profitability is astounding. Some of these deposits have been noted to contain nearly 20% copper in megaton quantities, versus the .4% that is typical of modern open-pit porphyry deposits, the immense pits in the earth that you've all seen pictures of.

Where you get to mining active black smokers, though, the situation gets interesting. In these cases, the smokers can physically grow by 3 feet or more per day, with god only knows what kinds of growth on the sulfide fields surrounding the smokers. Experts have been speculating that you could attach a pipe to the end of a black smoker and from there dry out and process the supercritical, black smoker water, which can be 50 weight percent or higher enriched in potentially economic metals. Here, we are for all intents and purposes talking about a renewable source of metals - an astounding proposition.

Success in black smoker mining will mean that land-based mining operations, which have immensely more potential for environmental harm, will begin to be phased out. The environmentalist movement will have thus scored a great victory. For this reason alone black smoker mining should be encouraged, though I'll be the first to march with the Sierra Club in insisting that 'oasis' black smokers that host unusual life-forms should not be mined. We geologists love the outdoors too!
And in addition to the hydrothermal vents, there are the manganese nodules that rest on the ocean floor.
Nodules lie on the seabed sediment, often partly or completely buried. They vary greatly in abundance, in some cases touching one another and covering more than 70% of the sea floor. The total amount of polymetallic nodules on the sea floor was estimated at 500 billion tons by Alan A. Archer of the London Geological Museum in 1981.

Polymetallic nodules are found in both shallow (e.g. the Baltic Sea) and deeper waters (e.g. the central Pacific), even in lakes, and are thought to have been a feature of the seas and oceans at least since the deep oceans oxidised in the Ediacaran period over 540 million years ago.
They represent totally different microecosystems from the vents.
Nodules lie loosely in the sand, but because they exist in places devoid of any other hard substrates—just muddy sediment—they end up acting like pseudo-reefs. Sponges and other sessile creatures can anchor themselves to the metallic rocks. They in turn provide habitat for a wide variety of other deep sea organisms...
And harvesting them requires a different process:
The machines mining companies are likely to use resemble giant potato harvesters. These giant 300-ton robot tractors trundle along the seafloor, ploughing through the sediment, scooping up manganese rocks. The resulting clouds of mud agitated by such a disturbance could be devastating to the fauna that live within it and in the water column.
In 2017, Hakai magazine showed a photo of a harvester (embedded at top of the post), and discussed regulatory challenges:
Officially, the nascent deep-sea-mining industry is governed by the International Seabed Authority (ISA), an intergovernmental organization established in 1996 by the United Nations Convention on the Law of the Sea (UNCLOS). The authority’s critical task is to coordinate its 168 member nations in establishing and enforcing regulations for the developing deep-sea-mining industry.

But the ISA’s teeth are just coming in, says Duncan Currie, a legal advisor to the Deep Sea Conservation Coalition, an advocacy organization. At the moment, the authority still hasn’t created an enforcement agency. In addition, “they won’t and they can’t force countries to comply with ISA regulations when drafting their own laws,” says Currie...

That the ISA has not yet landed on a set of rules puts countries such as Papua New Guinea—where Nautilus plans to open the first commercial deep-sea-mining operation—in an uncertain state. There’s no international template for Papua New Guinea to follow, says Conn Nugent, director of the Pew Charitable Trusts’ efforts to study and guide the development of seabed mining. Papua New Guinea’s Mining Act governs both onshore and offshore activities.

The ISA has also yet to determine how it will enforce regulations and respond to allegations of noncompliance. There are provisions within its mandate to create an inspection arm, says Lodge, but it has not been established because mining has yet to begin...

Besides, says Lodge, deep-sea mining is not a fly-by-night enterprise—a deep-sea-mining operation requires an investment of hundreds of millions of dollars. This means that companies will have to get money from banks, and banks want certainty. “The consequences of license denial are extremely high,” says Lodge. A company that opts to go rogue after failing to get ISA approval will quickly find itself without the financial backing it needs to operate.
The reason I'm writing this up now is because The Atlantic has just published a longread on the subject - History's Largest Mining Operation Is About to Begin.  The author is not sanguine about the future:
Today, many of the largest mineral corporations in the world have launched underwater mining programs. On the west coast of Africa, the De Beers Group is using a fleet of specialized ships to drag machinery across the seabed in search of diamonds. In 2018, those ships extracted 1.4 million carats from the coastal waters of Namibia; in 2019, De Beers commissioned a new ship that will scrape the bottom twice as quickly as any other vessel. Another company, Nautilus Minerals, is working in the territorial waters of Papua New Guinea to shatter a field of underwater hot springs lined with precious metals, while Japan and South Korea have embarked on national projects to exploit their own offshore deposits. But the biggest prize for mining companies will be access to international waters, which cover more than half of the global seafloor and contain more valuable minerals than all the continents combined...

Regulations for ocean mining have never been formally established. The United Nations has given that task to an obscure organization known as the International Seabed Authority, which is housed in a pair of drab gray office buildings at the edge of Kingston Harbour, in Jamaica. Unlike most UN bodies, the ISA receives little oversight. It is classified as “autonomous” and falls under the direction of its own secretary general, who convenes his own general assembly once a year, at the ISA headquarters. For about a week, delegates from 168 member states pour into Kingston from around the world, gathering at a broad semicircle of desks in the auditorium of the Jamaica Conference Centre. Their assignment is not to prevent mining on the seafloor but to mitigate its damage—selecting locations where extraction will be permitted, issuing licenses to mining companies, and drafting the technical and environmental standards of an underwater Mining Code...

The companies with permits to explore these regions have raised breathtaking sums of venture capital. They have designed and built experimental vehicles, lowered them to the bottom, and begun testing methods of dredging and extraction while they wait for the ISA to complete the Mining Code and open the floodgates to commercial extraction...

At full capacity, these companies expect to dredge thousands of square miles a year. Their collection vehicles will creep across the bottom in systematic rows, scraping through the top five inches of the ocean floor. Ships above will draw thousands of pounds of sediment through a hose to the surface, remove the metallic objects, known as polymetallic nodules, and then flush the rest back into the water. Some of that slurry will contain toxins such as mercury and lead, which could poison the surrounding ocean for hundreds of miles. The rest will drift in the current until it settles in nearby ecosystems...

The ISA has issued more mining licenses for nodules than for any other seabed deposit. Most of these licenses authorize contractors to exploit a single deepwater plain. Known as the Clarion-Clipperton Zone, or CCZ, it extends across 1.7 million square miles between Hawaii and Mexico—wider than the continental United States. When the Mining Code is approved, more than a dozen companies will accelerate their explorations in the CCZ to industrial-scale extraction. Their ships and robots will use vacuum hoses to suck nodules and sediment from the seafloor, extracting the metal and dumping the rest into the water.
Map of the CCZ below.  Black squares are no-mining zones; white ones are being explored for mining.
 
"We’re about to make one of the biggest transformations that humans have ever made to the surface of the planet. We’re going to strip-mine a massive habitat, and once it’s gone, it isn’t coming back.”
More at The Atlantic.  For reference: Economic minerals associated with black smokers (2006)
05 Feb 01:42

Bonsai

by Minnesotastan

Created by bonsai master Masahiko Kimura
His unconventional bonsai creations have stirred controversy at first. Deemed by some traditionalists as a non-conforming artist, Kimura continued to break the traditional rules of bonsai making. Typically, the art involves cultivating a single tree or shrub planted on a container. Instead of planting just one miniaturized tree, Kimura brilliantly created a mini-forest sprouting from a slanted deadwood. He has produced and sold several versions of the Hinoki Forest. But the original version, which he created more than 20 years ago, still sits proudly in his garden. His garden is located in Omiya, Japan and is open to the public upon request.
Image via
05 Feb 01:30

Words that exist only in the plural form

by Minnesotastan
  • Names of devices: 
    • bellowsbinocularsforcepsgallowsglassespliers, scissorsshearstongs.
  • Names of items of clothing: 
    • bracesbriefsjeansknickerspantspyjamasshortstightstrousers.
Discussion at Lexico.
27 Jan 22:34

Nonlinear control in the nematode C. elegans. (arXiv:2001.08332v2 [q-bio.NC] UPDATED)

by Megan Morrison, Charles Fieseler, J. Nathan Kutz

Recent whole-brain calcium imaging recordings of the nematode C. elegans have demonstrated that neural activity is dominated by dynamics on a low-dimensional manifold that can be clustered according to behavioral states. Despite progress in modeling the dynamics with linear or locally linear models, it remains unclear how a single network of neurons can produce the observed features. In particular, there are multiple clusters, or fixed points, observed in the data which cannot be characterized by a single linear model. We propose a nonlinear control model which is global and parameterized by only four free parameters that match the features displayed by the low-dimensional C. elegans neural activity. In addition to reproducing the average probability distribution of the data, long and short time-scale changes in transition statistics can be characterized via changes in a single parameter. Some of these macro-scale transitions have experimental correlates to single neuro-modulators that seem to act as biological controls, allowing this model to generate testable hypotheses about the effect of these neuro-modulators on the global dynamics. The theory provides an elegant characterization of the neuron population dynamics in C. elegans. Moreover, the mathematical structure of the nonlinear control framework provides a paradigm that can be generalized to more complex systems with an arbitrary number of behavioral states.

11 Jan 02:33

East, West, South and North Somewhat.

by noreply@blogger.com (Atrios)
At least Rumsfeld had a bit of a poet's soul.

03 Jan 20:28

The Real Butterfly Effect

by Sabine Hossenfelder
If a butterfly flaps its wings in China today, it may cause a tornado in America next week. Most of you will be familiar with this “Butterfly Effect” that is frequently used to illustrate a typical behavior of chaotic systems: Even smallest disturbances can grow and have big consequences. The name “Butterfly Effect” was popularized by James Gleick in his 1987 book “Chaos” and is usually
03 Jan 01:05

Quantum Dominance, Hegemony, and Superiority

by Scott

Yay! I’m now a Fellow of the ACM. Along with my fellow new inductee Peter Shor, who I hear is a real up-and-comer in the quantum computing field. I will seek to use this awesome responsibility to steer the ACM along the path of good rather than evil.

Also, last week, I attended the Q2B conference in San Jose, where a central theme was the outlook for practical quantum computing in the wake of the first clear demonstration of quantum computational supremacy. Thanks to the folks at QC Ware for organizing a fun conference (full disclosure: I’m QC Ware’s Chief Scientific Advisor). I’ll have more to say about the actual scientific things discussed at Q2B in future posts.

None of that is why you’re here, though. You’re here because of the battle over “quantum supremacy.”

A week ago, my good friend and collaborator Zach Weinersmith, of SMBC Comics, put out a cartoon with a dark-curly-haired scientist named “Dr. Aaronson,” who’s revealed on a hot mic to be an evil “quantum supremacist.” Apparently a rush job, this cartoon is far from Zach’s finest work. For one thing, if the character is supposed to be me, why not draw him as me, and if he isn’t, why call him “Dr. Aaronson”? In any case, I learned from talking to Zach that the cartoon’s timing was purely coincidental: Zach didn’t even realize what a hornet’s-nest he was poking with this.

Ever since John Preskill coined it in 2012, “quantum supremacy” has been an awkward term. Much as I admire John Preskill’s wisdom, brilliance, generosity, and good sense, in physics as in everything else—yeah, “quantum supremacy” is not a term I would’ve coined, and it’s certainly not a hill I’d choose to die on. Once it had gained common currency, though, I sort of took a liking to it, mostly because I realized that I could mine it for dark one-liners in my talks.

The thinking was: even as white supremacy was making its horrific resurgence in the US and around the world, here we were, physicists and computer scientists and mathematicians of varied skin tones and accents and genders, coming together to pursue a different and better kind of supremacy—a small reflection of the better world that we still believed was possible. You might say that we were reclaiming the word “supremacy”—which, after all, just means a state of being supreme—for something non-sexist and non-racist and inclusive and good.

In the world of 2019, alas, perhaps it was inevitable that people wouldn’t leave things there.

My first intimation came a month ago, when Leonie Mueck—someone who I’d gotten to know and like when she was an editor at Nature handling quantum information papers—emailed me about her view that our community should abandon the term “quantum supremacy,” because of its potential to make women and minorities uncomfortable in our field. She advocated using “quantum advantage” instead.

So I sent Leonie back a friendly reply, explaining that, as the father of a math-loving 6-year-old girl, I understood and shared her concerns—but also, that I didn’t know an alternative term that really worked.

See, it’s like this. Preskill meant “quantum supremacy” to refer to a momentous event that seemed likely to arrive in a matter of years: namely, the moment when programmable quantum computers would first outpace the ability of the fastest classical supercomputers on earth, running the fastest algorithms known by humans, to simulate what the quantum computers were doing (at least on special, contrived problems). And … “the historic milestone of quantum advantage”? It just doesn’t sound right. Plus, as many others pointed out, the term “quantum advantage” is already used to refer to … well, quantum advantages, which might fall well short of supremacy.

But one could go further. Suppose we did switch to “quantum advantage.” Couldn’t that term, too, remind vulnerable people about the unfair advantages that some groups have over others? Indeed, while “advantage” is certainly subtler than “supremacy,” couldn’t that make it all the more insidious, and therefore dangerous?

Oblivious though I sometimes am, I realized Leonie would be unhappy if I offered that, because of my wholehearted agreement, I would henceforth never again call it “quantum supremacy,” but only “quantum superiority,” “quantum dominance,” or “quantum hegemony.”

But maybe you now see the problem. What word does the English language provide to describe one thing decisively beating or being better than a different thing for some purpose, and which doesn’t have unsavory connotations?

I’ve heard “quantum ascendancy,” but that makes it sound like we’re a UFO cult—waiting to ascend, like ytterbium ions caught in a laser beam, to a vast quantum computer in the sky.

I’ve heard “quantum inimitability” (that is, inability to imitate using a classical computer), but who can pronounce that?

Yesterday, my brilliant former student Ewin Tang (yes, that one) relayed to me a suggestion by Kevin Tian: “quantum eclipse” (that is, the moment when quantum computers first eclipse classical ones for some task). But would one want to speak of a “quantum eclipse experiment”? And shouldn’t we expect that, the cuter and cleverer the term, the harder it will be to use unironically?

In summary, while someone might think of a term so inspired that it immediately supplants “quantum supremacy” (and while I welcome suggestions), I currently regard it as an open problem.

Anyway, evidently dissatisfied with my response, last week Leonie teamed up with 13 others to publish a letter in Nature, which was originally entitled “Supremacy is for racists—use ‘quantum advantage,'” but whose title I see has now been changed to the less inflammatory “Instead of ‘supremacy’ use ‘quantum advantage.'” Leonie’s co-signatories included four of my good friends and colleagues: Alan Aspuru-Guzik, Helmut Katzgraber, Anne Broadbent, and Chris Granade (the last of whom got started in the field by helping me edit Quantum Computing Since Democritus).

(Update: Leonie pointed me to a longer list of signatories here, at their website called “quantumresponsibility.org.” A few names that might be known to Shtetl-Optimized readers are Andrew White, David Yonge-Mallo, Debbie Leung, Matt Leifer, Matthias Troyer.)

Their letter says:

The community claims that quantum supremacy is a technical term with a specified meaning. However, any technical justification for this descriptor could get swamped as it enters the public arena after the intense media coverage of the past few months.

In our view, ‘supremacy’ has overtones of violence, neocolonialism and racism through its association with ‘white supremacy’. Inherently violent language has crept into other branches of science as well — in human and robotic spaceflight, for example, terms such as ‘conquest’, ‘colonization’ and ‘settlement’ evoke the terra nullius arguments of settler colonialism and must be contextualized against ongoing issues of neocolonialism.

Instead, quantum computing should be an open arena and an inspiration for a new generation of scientists.

When I did an “Ask Me Anything” session, as the closing event at Q2B, Sarah Kaiser asked me to comment on the Nature petition. So I repeated what I’d said in my emailed response to Leonie—running through the problems with each proposed alternative term, talking about the value of reclaiming the word “supremacy,” and mostly just trying to diffuse the tension by getting everyone laughing together. Sarah later tweeted that she was “really disappointed” in my response.

Then the Wall Street Journal got in on the action, with a brief editorial (warning: paywalled) mocking the Nature petition:

There it is, folks: Mankind has hit quantum wokeness. Our species, akin to Schrödinger’s cat, is simultaneously brilliant and brain-dead. We built a quantum computer and then argued about whether the write-up was linguistically racist.

Taken seriously, the renaming game will never end. First put a Sharpie to the Supremacy Clause of the U.S. Constitution, which says federal laws trump state laws. Cancel Matt Damon for his 2004 role in “The Bourne Supremacy.” Make the Air Force give up the term “air supremacy.” Tell lovers of supreme pizza to quit being so chauvinistic about their toppings. Please inform Motown legend Diana Ross that the Supremes are problematic.

The quirks of quantum mechanics, some people argue, are explained by the existence of many universes. How did we get stuck in this one?

Steven Pinker also weighed in, with a linguistically-informed tweetstorm:

This sounds like something from The Onion but actually appeared in Nature … It follows the wokified stigmatization of other innocent words, like “House Master” (now, at Harvard, Residential Dean) and “NIPS” (Neural Information Processing Society, now NeurIPS). It’s a familiar linguistic phenomenon, a lexical version of Gresham’s Law: bad meanings drive good ones out of circulation. Examples: the doomed “niggardly” (no relation to the n-word) and the original senses of “cock,” “ass,” “prick,” “pussy,” and “booty.” Still, the prissy banning of words by academics should be resisted. It dumbs down understanding of language: word meanings are conventions, not spells with magical powers, and all words have multiple senses, which are distinguished in context. Also, it makes academia a laughingstock, tars the innocent, and does nothing to combat actual racism & sexism.

Others had a stronger reaction. Curtis Yarvin, better known as Mencius Moldbug, is one of the founders of “neoreaction” (and a significant influence on Steve Bannon, Michael Anton, and other Trumpists). Regulars might remember that Yarvin argued with me in Shtetl-Optimized‘s comment section, under a post in which I denounced Trump’s travel ban and its effects on my Iranian PhD student. Since then, Yarvin has sent me many emails, which have ranged from long to extremely long, and whose message could be summarized as: “[labored breathing] Abandon your liberal Enlightenment pretensions, young Nerdwalker. Come over the Dark Side.”

After the “supremacy is for racists” letter came out in Nature, though, Yarvin sent me his shortest email ever. It was simply a link to the letter, along with the comment “I knew it would come to this.”

He meant: “What more proof do you need, young Nerdawan, that this performative wokeness is a cancer that will eventually infect everything you value—even totally apolitical research in quantum information? And by extension, that my whole worldview, which warned of this, is fundamentally correct, while your faith in liberal academia is naïve, and will be repaid only with backstabbing?”

In a subsequent email, Yarvin predicted that in two years, the whole community will be saying “quantum advantage” instead of “quantum supremacy,” and in five years I’ll be saying “quantum advantage” too. As Yarvin famously wrote: “Cthulhu may swim slowly. But he only swims left.”

So what do I really think about this epic battle for (and against) supremacy?

Truthfully, half of me just wants to switch to “quantum advantage” right now and be done with it. As I said, I know some of the signatories of the Nature letter to be smart and reasonable and kind. They don’t wish to rid the planet of everyone like me. They’re not Amanda Marcottes or Arthur Chus. Furthermore, there’s little I despise more than a meaty scientific debate devolving into a pointless semantic one, with brilliant friend after brilliant friend getting sucked into the vortex (“you too?”). I’m strongly in the Pinkerian camp, which holds that words are just arbitrary designators, devoid of the totemic power to dictate thoughts. So if friends and colleagues—even just a few of them—tell me that they find some word I use to be offensive, why not just be a mensch, apologize for any unintended hurt, switch words midsentence, and continue discussing the matter at hand?

But then the other half of me wonders: once we’ve ceded an open-ended veto over technical terms that remind anyone of anything bad, where does it stop? How do we ever certify a word as kosher? At what point do we all get to stop arguing and laugh together?

To make this worry concrete, look back at Sarah Kaiser’s Twitter thread—the one where she expresses disappointment in me. Below her tweet, someone remarks that, besides “quantum supremacy,” the word “ancilla” (as in ancilla qubit, a qubit used for intermediate computation or other auxiliary purposes) is problematic as well. Here’s Sarah’s response:

I agree, but I wanted to start by focusing on the obvious one, Its harder for them to object to just one to start with, then once they admit the logic, we can expand the list

(What would Curtis Yarvin say about that?)

You’re probably now wondering: what’s wrong with “ancilla”? Apparently, in ancient Rome, an “ancilla” was a female slave, and indeed that’s the Latin root of the English adjective “ancillary” (as in “providing support to”). I confess that I hadn’t known that—had you? Admittedly, once you do know, you might never again look at a Controlled-NOT gate—pitilessly flipping an ancilla qubit, subject only to the whims of a nearby control qubit—in quite the same way.

(Ah, but the ancilla can fight back against her controller! And she does—in the Hadamard basis.)

The thing is, if we’re gonna play this game: what about annihilation operators? Won’t those need to be … annihilated from physics?

And what about unitary matrices? Doesn’t their very name negate the multiplicity of perspectives and cultures?

What about Dirac’s oddly-named bra/ket notation, with its limitless potential for puerile jokes, about the “bra” vectors displaying their contents horizontally and so forth? (Did you smile at that, you hateful pig?)

What about daggers? Don’t we need a less violent conjugate tranpose?

Not to beat a dead horse, but once you hunt for examples, you realize that the whole dictionary is shot through with domination and brutality—that you’d have to massacre the English language to take it out. There’s nothing special about math or physics in this respect.

The same half of me also thinks about my friends and colleagues who oppose claims of quantum supremacy, or even the quest for quantum supremacy, on various scientific grounds. I.e., either they don’t think that the Google team achieved what it said, or they think that the task wasn’t hard enough for classical computers, or they think that the entire goal is misguided or irrelevant or uninteresting.

Which is fine—these are precisely the arguments we should be having—except that I’ve personally seen some of my respected colleagues, while arguing for these positions, opportunistically tack on ideological objections to the term “quantum supremacy.” Just to goose up their case, I guess. And I confess that every time they did this, it made me want to keep saying “quantum supremacy” from now till the end of time—solely to deny these colleagues a cheap and unearned “victory,” one they apparently felt they couldn’t obtain on the merits alone. I realize that this is childish and irrational.

Most of all, though, the half of me that I’m talking about thinks about Curtis Yarvin and the Wall Street Journal editorial board, cackling with glee to see their worldview so dramatically confirmed—as theatrical wokeness, that self-parodying modern monstrosity, turns its gaze on (of all things) quantum computing research. More red meat to fire up the base—or at least that sliver of the base nerdy enough to care. And the left, as usual, walks right into the trap, sacrificing its credibility with the outside world to pursue a runaway virtue-signaling spiral.

The same half of me thinks: do we really want to fight racism and sexism? Then let’s work together to assemble a broad coalition that can defeat Trump. And Jair Bolsonaro, and Viktor Orbán, and all the other ghastly manifestations of humanity’s collective lizard-brain. Then, if we’re really fantasizing, we could liberalize the drug laws, and get contraception and loans and education to women in the Third World, and stop the systematic disenfranchisement of black voters, and open up the world’s richer, whiter, and higher-elevation countries to climate refugees, and protect the world’s remaining indigenous lands (those that didn’t burn to the ground this year).

In this context, the trouble with obsessing over terms like “quantum supremacy” is not merely that it diverts attention, while contributing nothing to fighting the world’s actual racism and sexism. The trouble is that the obsessions are actually harmful. For they make academics—along with progressive activists—look silly. They make people think that we must not have meant it when we talked about the existential urgency of climate change and the world’s other crises. They pump oxygen into right-wing echo chambers.

But it’s worse than ridiculous, because of the message that I fear is received by many outside the activists’ bubble. When you say stuff like “[quantum] supremacy is for racists,” what’s heard might be something more like:

“Watch your back, you disgusting supremacist. Yes, you. You claim that you mentor women and minorities, donate to good causes, try hard to confront the demons in your own character? Ha! None of that counts for anything with us. You’ll never be with-it enough to be our ally, so don’t bother trying. We’ll see to it that you’re never safe, not even in the most abstruse and apolitical fields. We’ll comb through your words—even words like ‘ancilla qubit’—looking for any that we can cast as offensive by our opaque and ever-shifting standards. And once we find some, we’ll have it within our power to end your career, and you’ll be reduced to groveling that we don’t. Remember those popular kids who bullied you in second grade, giving you nightmares of social ostracism that persist to this day? We plan to achieve what even those bullies couldn’t: to shame you with the full backing of the modern world’s moral code. See, we’re the good guys of this story. It’s goodness itself that’s branding you as racist scum.”

In short, I claim that the message—not the message intended, of course, by anyone other than a Chu or a Marcotte or a SneerClubber, but the message received—is basically a Trump campaign ad. I claim further that our civilization’s current self-inflicted catastrophe will end—i.e., the believers in science and reason and progress and rule of law will claw their way back to power—when, and only when, a generation of activists emerges that understands these dynamics as well as Barack Obama did.

Wouldn’t it be awesome if, five years from now, I could say to Curtis Yarvin: you were wrong? If I could say to him: my colleagues and I still use the term ‘quantum supremacy’ whenever we care to, and none of us have been cancelled or ostracized for it—so maybe you should revisit your paranoid theories about Cthulhu and the Cathedral and so forth? If I could say: quantum computing researchers now have bigger fish to fry than arguments over words—like moving beyond quantum supremacy to the first useful quantum simulations, as well as the race for scalability and fault-tolerance? And even: progressive activists now have bigger fish to fry too—like retaking actual power all over the world?

Anyway, as I said, that’s how half of me feels. The other half is ready to switch to “quantum advantage” or any other serviceable term and get back to doing science.

02 Jan 22:46

London Calling with Career Opportunities

by woit

At some point within the past couple years I noticed that one blog that had Not Even Wrong on its blogroll was the blog of Dominic Cummings, who was often getting credited with masterminding the political campaign that got the British to vote (narrowly) for Brexit in 2016. Cummings has had further success recently as Chief Special Adviser to British Prime Minister Boris Johnson, with a blow-out election victory three weeks ago putting him securely in control of the British state.

Today on his blog Cummings has, invoking Grothendieck, posted a job advertisement: ‘Two hands are a lot’ — we’re hiring data scientists, project managers, policy experts, assorted weirdos…. He’s looking for mathematicians, physicists and others to join him to change British society, working

in the intersection of:

  • the selection, education and training of people for high performance
  • the frontiers of the science of prediction
  • data science, AI and cognitive technologies (e.g Seeing Rooms, ‘authoring tools designed for arguing from evidence’, Tetlock/IARPA prediction tournaments that could easily be extended to consider ‘clusters’ of issues around themes like Brexit to improve policy and project management)
  • communication (e.g Cialdini)
  • decision-making institutions at the apex of government.

For some other descriptions of who Cummings would like to hire, on the economics side there’s:

The ideal candidate might, for example, have a degree in maths and economics, worked at the LHC in one summer, worked with a quant fund another summer, and written software for a YC startup in a third summer!

We’ve found one of these but want at least one more.

He also wants “Super-talented weirdos”, with examples given from William Gibson novels, such as “that Chinese-Cuban free runner from a crime family hired by the KGB.”

The remarkable things to me about this long document are what it doesn’t contain. In particular I see nothing at all about any specific policy goals. Usually a new government would recruit people by appealing to their desire to make the world a better place in some specific way, but there’s nothing about that here. The goal is to control the government and what the British population believes, but to what end?

In addition, a more conventional hiring process would be asking for candidates of high ethical values, with some devotion to telling the truth. Cummings seems to be asking for exactly the opposite: best if your background is “from a crime family hired by the KGB.”

Best of wishes to my British readers, now joining the US and other nations in a new dystopic post-truth era. It’s massively depressing to me to see how this has worked out here, I hope you do better. Maybe you should be sending in your applications to Cummings and hoping to sign up for a role in the new power structure. If so, tell him “Not Even Wrong” sent you…

Update: For more on Cummings, there’s a good Financial Times article.

06 Dec 15:16

Same-Sex behavior in animals - a new view.

by mdbownds@wisc.edu (Deric Bownds)
Monk et al. offer a fresh perspective on the "problem" of how same-sex sexual behavior could have evolved. It is a problem only if different-sex sexual behavior is the baseline condition for animals, from which single-sex behavior has evolved. The authors suggest that same-sex behavior is bound up in the very origins of animal sex. It hasn’t had to continually re-evolve: It’s always been there. The arguments of Monk and collaborators are summarized in a review by Elbein:
Instead of wondering why same-sex behavior had independently evolved in so many species, Ms. Monk and her colleagues suggest that it may have been present in the oldest parts of the animal family tree. The earliest sexually reproducing animals may have mated with any other individual they came across, regardless of sex. Such reproductive strategies are still practiced today by hermaphroditic species, like snails, and species that don’t appear to differentiate, like sea urchins.
Over time, Ms. Monk said, sexual signals evolved — different sizes, colors, anatomical features and behaviors — allowing different sexes to more accurately target each other for reproduction. But same-sex behavior continued in some organisms, leading to diverse sexual behaviors and strategies across the animal kingdom. And while same-sex behavior may grant some evolutionary benefits, an ancient origin would mean those benefits weren’t required for it to exist.
But how has same-sex behavior stuck around? The answer may be that such behaviors aren’t as evolutionarily costly as assumed. Traditionally, Ms. Monk said, any mating behavior that doesn’t produce young is seen as a waste. But animal behavior often doesn’t fit neatly into an economic accounting of costs and benefits.
Here is the abstract of Monk et al.:
Same-sex sexual behaviour (SSB) has been recorded in over 1,500 animal species with a widespread distribution across most major clades. Evolutionary biologists have long sought to uncover the adaptive origins of ‘homosexual behaviour’ in an attempt to resolve this apparent Darwinian paradox: how has SSB repeatedly evolved and persisted despite its presumed fitness costs? This question implicitly assumes that ‘heterosexual’ or exclusive different-sex sexual behaviour (DSB) is the baseline condition for animals, from which SSB has evolved. We question the idea that SSB necessarily presents an evolutionary conundrum, and suggest that the literature includes unchecked assumptions regarding the costs, benefits and origins of SSB. Instead, we offer an alternative null hypothesis for the evolutionary origin of SSB that, through a subtle shift in perspective, moves away from the expectation that the origin and maintenance of SSB is a problem in need of a solution. We argue that the frequently implicit assumption of DSB as ancestral has not been rigorously examined, and instead hypothesize an ancestral condition of indiscriminate sexual behaviours directed towards all sexes. By shifting the lens through which we study animal sexual behaviour, we can more fruitfully examine the evolutionary history of diverse sexual strategies.
26 Nov 16:16

The Golomb--Dickman Constant

by john
MathML-enabled post (click for more details).

I’m falling in love with random permutations. There’s something both simple and fairly deep about them. I like to visualize a random permutation as a “gas of cycles”, governed by the laws of statistical mechanics. I haven’t gotten very with this analogy yet.

MathML-enabled post (click for more details).

Here’s one of the many cute facts about random permutations. Let a na_n be the average length of the longest cycle in a permutation, averaged over all permutations of an nn-element set. Then a na_n is asymptotically equal to λn\lambda n where

λ≈0.6243299885… \lambda \approx 0.6243299885 \dots

is called the Golomb–Dickman constant. There’s a cool formula for this constant: λ=∫ 0 1e Li(x)dxwhereLi(x)=∫ 0 xdtlnt \lambda = \int_0^1 e^{\mathrm{Li}(x)} dx \; \; where \; \; Li(x) = \int_0^x \frac{dt}{\ln t} But nobody has been able to prove that it’s irrational!

The Golomb–Dickman constant also shows up in number theory… in a very similar way! If you randomly choose a huge nn-digit integer, the average number of digits of its largest prime factor is asymptotic to λn\lambda n.

So, there’s a connection between prime factorizations and random permutations! And this fact is both simpler and more interesting to me than the Golomb–Dickman constant. You can read more about this in Sections 3.10-3.12 here:

The Golomb–Dickman constant is a kind of relative of Euler’s constant, though there’s no known formula expressing one in terms of the other.

Here’s another appearance of this constant. Say you randomly choose a function from a huge nn-element set to itself. Then the average length of its longest periodic orbit is asymptotic to

λπn2 \lambda \; \sqrt{\frac{\pi n}{2}}

26 Nov 16:07

Random Permutations (Part 1)

by john
MathML-enabled post (click for more details).

I’m going to solve some problems on random permutations in my combinatorics class, to illustrate some of the ideas on species and generating functions, but also to bring in some ideas from complex analysis.

In all these problems we choose permutations randomly from S nS_n, with each permutation having probability 1/n!1/n! of being chosen.

I’ll start with one that’s easy, given the stuff I’ve already explained in class.

MathML-enabled post (click for more details).

Puzzle 1. What is the probability that a randomly chosen permutation of an nn-element set has exactly kk fixed points? What does this probability converge to as n→∞n \to \infty?

In homework the students already computed the probability that a randomly chosen permutation of an nn-element set has no fixed points. A permutation with no fixed points is called a derangement, and the number of derangements of an nn-element set is called the subfactorial !n!\!n.

Using the inclusion-exclusion principle, the number of derangements of {1,…,n}\{1,\dots, n\} is the number of permutations of this set, minus the number of permutations that fix the point 11, minus the number that fix the point 22,… minus the number that fix the point nn, plus the number that fix the points 11 and 22, plus the number that fix the points 11 and 33,… minus the number that fix the points 1,21, 2 and 33,… and so on.

In short:

!n=n!−(n1)(n−1)!+(n2)(n−2)!−⋯+(−1) n(nn)(n−n)! !n = n! \; -\; \binom{n}{1} (n-1)! + \binom{n}{2} (n-2)! - \cdots + (-1)^n \binom{n}{n} (n-n)!

We can simplify this to

!n=n!(10!−11!+12!−⋯+(−1) nn!) !\!n = n! \, \left(\frac{1}{0!} - \frac{1}{1!} + \frac{1}{2!} - \cdots + \frac{(-1)^n}{n!} \right)

Thus, the probability that a permutation of an nn-element set has no fixed points is

!nn!=10!−11!+12!−⋯+(−1) nn! \frac{!\!n}{n!} = \frac{1}{0!} - \frac{1}{1!} + \frac{1}{2!} - \cdots + \frac{(-1)^n}{n!}

and this approaches 1/e1/e as n→∞n \to \infty. So cool.

Now, what about kk fixed points? To choose a permutation of an nn-element set with kk fixed points, we need to choose kk points and then choose a derangement of the remaining (n−k)(n-k)-element set. There are

(nk)!(n−k) \binom{n}{k} \, !(n-k)

ways to do this. Thus, the probability that a permutation of an nn-element set has kk fixed points is

(nk)!(n−k)n! \binom{n}{k} \; \frac{!\!(n-k)}{n!}

which can be written more charmingly as

1k!!(n−k)(n−k)! \frac{1}{k!} \; \frac{!\!(n-k)}{(n-k)!}

We have seen that as n→∞n \to \infty we have

!(n−k)(n−k)!→1e \frac{!\!(n-k)}{(n-k)!} \to \frac{1}{e}

Thus, as n→∞n \to \infty, the probability that a permutation of an nn-element set has kk fixed points approaches

1ek! \frac{1}{e \, k!}

Note that these probabilities sum to 11, as they must.

Puzzle 2. In the n→∞n \to \infty limit, what is the expected number of fixed points of a permutation of an nn-element set?

You might naively think it would be infinite, but remember as we increase the size of our set we decrease the probability that any point gets mapped to itself.

We know that in the n→∞n \to \infty limit the probability of there being kk fixed points is

1ek! \frac{1}{e \, k!}

so in this limit, the expected number of fixed points is

∑ k≥0k1k!e=1e∑ k≥11(k−1)!=1 \sum_{k \ge 0} k \frac{1}{k! e} = \frac{1}{e} \sum_{k \ge 1} \frac{1}{(k-1)!} = 1

Exactly one!

You might also wonder what’s the expected number of fixed points for an arbitrary finite nn, but I’ll leave that to you.

22 Nov 21:33

Discovery Of The First Human Retro-Giant Virus: Description of its morphology, retroviral kinase and ability to induce tumours in mice

by Lusi, E. A., Caicci, F.
Background: The study of retroviruses dates back to the early 1900s during investigations on neoplastic diseases in chickens. Subsequently, Robert Gallo reported the first human retrovirus HLTV in 1980. What we report here is not an archetypal retrovirus, but the discovery of an oncogenic giant microbial agent with a mega-genome, where the transforming retroviral nature co-exists with multiple archaeal oncogenes. Methods: After their isolation from human T cells Leukaemia, these organisms were examined at electron microscopy, tested for reverse transcriptase activity, fully sequenced, used for transformation tests on NIH-3T3 cells in vitro and tumours formation in mice. Same type of particles were also isolated from Canine Transmissible Venereal Tumour (CTVT), the oldest contagious cancer in nature. Results: EM showed the presence of giant viral particles displaying retroviral antigens. These microbial entities harbour in their mega-genome a transforming retroviral kinase, cell-based oncogenes and have reverse transcriptase activity. The purified viral particles transformed NIH-3T3 cells and induced metastatic tumours in nude mice, three weeks post infection. Ruling out the possible presence of filterable retroviruses, a filtered supernatant did not display RT activity and did not transforms. Conclusions: We discovered an ancestral microbial agent, acutely transforming. For its giant dimensions, the ability to retain the Gram stain, the presence of a mega-genome and its retroviral nature, we tentatively named the agent Retro-Giant-Virus (RGV). However, distinct from amoeba giant Mimiviruses, this transforming human agent has a different nature and does not require for its isolation amoeba co-culture, since amoeba is not its natural host. The morphology, biology and genetic features allocate this mammalian giant microbe halfway in between a classic oncogenic virus and an infectious cancer cell. Its transforming nature goes with its constant ability to induce tumours formation in mice.
22 Nov 17:05

The "technical debt" of America's infrastructure

by Minnesotastan
Excerpts from a very sobering article in The Atlantic:
A kind of toxic debt is embedded in much of the infrastructure that America built during the 20th century. For decades, corporate executives, as well as city, county, state, and federal officials, not to mention voters, have decided against doing the routine maintenance and deeper upgrades to ensure that electrical systems, roads, bridges, dams, and other infrastructure can function properly under a range of conditions. Kicking the can down the road like this is often seen as the profit-maximizing or politically expedient option. But it’s really borrowing against the future, without putting that debt on the books.

In software development, engineers have long noted that taking the easy way out of coding problems builds up what they call “technical debt,” as the tech journalist Quinn Norton has written...

Almost everywhere you look in the built environment, toxic technical-debt bubbles are growing and growing and growing. This is true of privately maintained systems such as PG&E’s and publicly maintained systems such as that of Chicago’s Department of Water Management. It’s extremely true of roads: Soon, perhaps 50 percent of Bay Area roads will be in some state of disrepair, not to mention the deeper work that must occur to secure the roadbeds, not just the asphalt on top.

Then there are the sewers and the wastewater plants. Stormwater drains. Levees. And just regular old drinking water. Per capita federal funding for water infrastructure has fallen precipitously since the 1970s. Cities are forced to make impossible decisions between funding different services. And even when they do have the money they need, officials make bad or corrupt decisions. So, water systems in the United States have built up a $1 trillion technical debt, which must be paid over the next 25 years. The problem is particularly acute in the Great Lakes states. One investigation, by American Public Media, found that from 2007 to 2018 Chicago residents’ water bills tripled, and Cleveland residents’ doubled. In Detroit, a city with a median income of less than $27,000, the average family paid $1,151 for water. At these rates, poor residents are far more likely to have their water shut off, and the systems still aren’t keeping up with the maintenance they need. Runaway technical debt makes it nearly impossible to pay the “interest,” which is just keeping the system running, let alone to start paying down the principal or start new capital projects.

All told, the American Society of Civil Engineers estimates that it will cost $3.6 trillion to get Americans back to an acceptable level of technical debt in our infrastructure.
The linked article by Quinn Norton is also sobering.
What Californians, as well as many other Americans, and hundreds of millions of people around the world need to give up on is living where they think they ought to be able to live. Californians are busy building new neighborhoods into the rightful territory of giant fast moving infernos; post-Hurricane Texans think they have the right to build in low-elevation Houston, and poverty-stricken Bangladeshis and Indonesians think they should hold on to the shores they’ve always lived on.
Houston is technical debt. New Orleans is technical debt. Puerto Rico is plagued by intertwined monetary and technical debt.
22 Nov 16:46

An introduction to "Dolly Parton's America"

by Minnesotastan


I long ago gave up radio in favor of podcasts.  The most interesting and enjoyable one I've heard this year is embedded above.
Radiolab creator and host Jad Abumrad spent the last two years following around music legend Dolly Parton, and we're here to say you should tune in! In this episode of Radiolab, we showcase the first of Jad's special series, Dolly Parton's America. In this intensely divided moment, one of the few things everyone still seems to agree on is Dolly Parton—but why? That simple question leads to a deeply personal, historical, and musical rethinking of one of America’s great icons.

We begin with a simple question: How did the queen of the boob joke become a feminist icon? Helen Morales, author of “Pilgrimage to Dollywood,” gave us a stern directive – look at the lyrics! So we dive into Dolly’s discography, starting with the early period of what Dolly calls “sad ass songs” to find remarkably prescient words of female pain, slut-shaming, domestic violence, and women being locked away in asylums by cheating husbands. We explore how Dolly took the centuries-old tradition of the Appalachian “murder ballad”—an oral tradition of men singing songs about brutally killing women—and flipped the script, singing from the woman’s point of view. And as her career progresses, the songs expand beyond the pain to tell tales of leaving abuse behind.
It's probably fair to say that "nobody doesn't like Dolly Parton."
JAD: Like, she tore right through all of that noise. Through the general election and beyond. And I kept bumping into people who would describe the experience of being at a Dolly show as, like, standing in an alternate vision of America than what was unfolding on the TV.

JESSIE WILKERSON: I remember just standing out in the lobby and just people watching, because it was the most diverse place I’ve ever been. I was seeing a multi-racial audience. People wearing cowboy hats and boots. I was seeing people in drag. Church ladies. Lesbians holding hands. Little girls who were there with their families.

WAYNE BLEDSOE: You had a whole audience of people who absolutely their philosophies were in opposition to each other co-mingling, and everybody is polite to each other.

JAD: So that was one thing that caught my attention. That in this very divided moment, Dolly seems to maybe be a kind of unifier. And after doing a little poking around, the data does kind of bear this out. If you look at her global Q Score, this is a measure of how well people think about your brand, globally. What they do is they assemble a very diverse sample of people, they ask them a bunch of questions, and out of all of these different brands that are out there, all these different performers, she is in the top 10 globally in terms of everybody's favorites. But she's almost number one when it comes to lack of negatives, if that makes any sense.
The embed above is from a Radiolab presentation.  The series is available here.
22 Nov 16:41

To detect a hidden "nannycam"

by Minnesotastan

Hidden cameras are everywhere nowadays.  Travelers especially need to be wary in rented rooms.  A WikiHow article shows how to find one using your smartphone.

Note the red dot in the blackness above (from a hidden camera) is not visible light - you could see that with your naked eye.  This is infrared light from the spy camera, detected by the front-facing camera on your phone.


More procedural details at the link.
21 Nov 20:19

Socially dominant, aggressive males are poor influencers of group-consensus in a social fish

by Rodriguez-Santiago, M., Nuehrenberg, P., Derry, J., Deussen, O., Garrison, L. K., Garza, S. F., Francisco, F., Hofmann, H., Jordan, A. L.
In many species, cultures, and contexts, social dominance reflects the ability to exert influence over the behavior of others. Yet the behavioral attributes of those in dominant positions, and the behaviors of actually influential individuals may not be the same, and the behavioral attributes that generate influence in one social context may reduce influence in others. The question of what makes an effective leader is therefore not straightforward, and has many answers depending on the context in which leadership and influence is to be manifested. Most importantly, social dominance cannot always be assumed to be equivalent with social influence. Here we examine whether socially dominant males in the cichlid fish Astatotilapia burtoni are more effective in exerting social influence than socially subordinate males. Using machine-vision based automated tracking of behavior, we find that dominant males in this species display behavioral traits that typify leadership across taxonomic systems - they are aggressive, occupy central social network positions, and lead group movements, whereas subordinate males are passive, socially peripheral, and have little influence over typical group movement. However, in a more complex group-consensus task the influence of dominant males breaks down, and subordinate males become more effective agents of social change. In a more sophisticated group consensus task involving a visual association task, the behavioral attributes that define male dominance - aggression, rapid movement, and increased physical distance to others - interfere with the ability of dominant males to generate group to consensus. Dominant males occupy more spatially distant positions, and had lower signal-to-noise ratio of informative behavior in the association task, while subordinate males are typically is close physical association with their group members, have high signal-to-noise behaviors in the association task, and equal visual connectivity to other group members as dominant males. The attributes that define effective social influence are therefore highly context-specific in this species. These results demonstrate that in this and many other species including humans, behavioral traits that are typical of socially dominant individuals may be the same that reduce their social influence in other contexts.
21 Nov 19:50

The Statistical Foundations of Colour Space

by Wilkins, L.
The idea of a colour space where distance corresponds to discriminability has been fundamental to colour vision research since the 19th century. Despite their long-standing success there is a contradiction between the geometric framework that is typically used in these spaces (a particular application of Riemannian geometry) and a view of the transduction of sensory information as the result of a stochastic process. When this is made explicit, a subtly different approach is suggested which turns out to provide a general, and more complete framework for colour space. It is argued further that not only is a contradiction avoided, but that this framework is both intuitive and of real practical value, in particular for researchers interested in the visual behaviour and ecology of animals.
15 Nov 18:57

Human Olfaction without Apparent Olfactory Bulbs

by Tali Weiss, Timna Soroka, Lior Gorodisky, Sagit Shushan, Kobi Snitz, Reut Weissgross, Edna Furman-Haran, Thijs Dhollander, Noam Sobel
The olfactory bulbs are the sole known relay station of odor information from nose to brain. Using MRI, Weiss et al. discover that ∼4% of left-handed women have normal olfaction without apparent olfactory bulbs. How these women can smell remains unknown.
13 Nov 01:50

Thermodynamic uncertainty relations constrain non-equilibrium fluctuations

by Jordan M. Horowitz

Nature Physics, Published online: 11 November 2019; doi:10.1038/s41567-019-0702-6

A new class of inequalities known as thermodynamic uncertainty relations provides quantitative tools for the description of physical systems out of equilibrium. A perspective is offered on these results and their future developments.
12 Nov 22:58

Einstein's E = mc^2 derivable from Heisenberg's Uncertainty Relations. (arXiv:1911.03818v1 [quant-ph])

by Sibel Baskal, Young S. Kim, Marilyn E. Noz

Heisenberg's uncertainty relation can be written in terms of the step-up and step-down operators in the harmonic oscillator representation. It is noted that the single-variable Heisenberg commutation relation contains the symmetry of the Sp(2) group which is isomorphic to the Lorentz group applicable to one time-like dimension and two space-like dimensions, known as the O(2,1) group. This group has three independent generators. The one-dimensional step-up and step-down operators can be combined into one two-by-two Hermitian matrix which contains three independent operators. If we use a two-variable Heisenberg commutation relation, the two pairs of independent step-up, step-down operators can be combined into a four-by-four block-diagonal Hermitian matrix with six independent parameters. It is then possible to add one off-diagonal two-by-two matrix and its Hermitian conjugate to complete the four-by-four Hermitian matrix. This off-diagonal matrix has four independent generators. There are thus ten independent generators. It is then shown that these ten generators can be linearly combined to the ten generators for the Dirac's two oscillator system leadingto the group isomorphic to the de Sitter group O(3,2), which can the be contracted to the inhomogeneous Lorentz group with four translation generators corresponding to the four-momentum in the Lorentz-covariant world. This Lorentz-covariant four-momentum is known as Einstein's E = mc^2.

31 Oct 13:37

BlackSheep: A Bioconductor and Bioconda package for differential extreme value analysis

by Blumenberg, L., Kawaler, E., Cornwell, M., Smith, S., Ruggles, K., Fenyo, D.
Nosimpler

EXTREEEEME

Unbiased assays such as shotgun proteomics and RNA-seq provide high-resolution molecular characterization of tumors. These assays measure molecules with highly varied distributions, making interpretation and hypothesis testing challenging. Samples with the most extreme measurements for a molecule can reveal the most interesting biological insights, yet are often excluded from analysis. Furthermore, rare disease subtypes are, by definition, underrepresented in cancer cohorts. To provide a strategy for identifying molecules aberrantly enriched in small sample cohorts, we present BlackSheep--a package for non-parametric description and differential analysis of genome-wide data, available at https://github.com/ruggleslab/blackSheep. BlackSheep is a complementary tool to other differential expression analysis methods that may be underpowered when analyzing small subgroups in a larger cohort.