Nosimpler

We study the stochastic dynamics of strongly-coupled excitable elements on a tree network. The peripheral nodes receive independent random inputs which may induce large spiking events propagating through the branches of the tree and leading to global coherent oscillations in the network. This scenario may be relevant to action potential generation in certain sensory neurons, which possess myelinated distal dendritic tree-like arbors with excitable nodes of Ranvier at peripheral and branching nodes and exhibit noisy periodic sequences of action potentials.

We focus on the spiking statistics of the central node, which fires in response to a noisy input at peripheral nodes. We show that, in the strong coupling regime, relevant to myelinated dendritic trees, the spike train statistics can be predicted from an isolated excitable element with rescaled parameters according to the network topology. Furthermore, we show that by varying the network topology the spike train statistics of the central node can be tuned to have a certain firing rate and variability, or to allow for an optimal discrimination of inputs applied at the peripheral nodes.

The increasing volume of ecologically and biologically relevant data has revealed a wide collection of emergent patterns in living systems. Analyzing different datasets, ranging from metabolic gene-regulatory to species interaction networks, we find that these networks are sparse, i.e. the percentage of the active interactions scales inversely proportional to the system size. This puzzling characteristic has been neither yet considered nor explained. Herein, we introduce the new concept of explorability, a measure of the ability of the system to adapt to newly intervening changes. We show that sparsity is an emergent property resulting from a variational principle aiming at the optimization of both explorability and dynamical robustness, the capacity of the system to remain stable after perturbations of the underlying dynamics. Networks with higher connectivities lead to an incremental difficulty to find better values for both the explorability and dynamical robustness, associated with the fine-tuning of the newly added interactions. A relevant characteristic of our solution is its scale invariance, that is, it remains optimal when several communities are assembled togheter. Connectivity is also a key ingredient determining ecosystem stability and our proposed solution contributes to solving May's celebrated complexity-stability paradox.

Replacing the function of a missing or paralyzed limb with a prosthetic device that acts and feels like one’s own limb is a major goal in applied neuroscience. Recent studies in nonhuman primates have shown that motor control and sensory feedback can be achieved by connecting sensors in a robotic...

Williams and Beer (2010) proposed a nonnegative mutual information decomposition, based on the construction of information gain lattices, which allows separating the information that a set of variables contains about another into components interpretable as the unique information of one variable, or redundant and synergy components. In this work we extend the framework of Williams and Beer (2010) focusing on the lattices that underpin the decomposition. We generalize the type of constructible lattices and examine the relations between the terms in different lattices, for example relating bivariate and trivariate decompositions. We point out that, in information gain lattices, redundancy components are invariant across decompositions, but unique and synergy components are decomposition-dependent. Exploiting the connection between different lattices we propose a procedure to construct, in the general multivariate case, information decompositions from measures of synergy or unique information. We introduce an alternative type of mutual information decompositions based on information loss lattices, with the role and invariance properties of redundancy and synergy components exchanged with respect to gain lattices. We study the correspondence between information gain and information loss lattices and we define dual decompositions that allow overcoming the intrinsic asymmetry between invariant and decomposition-dependent components, which hinders the consistent joint characterization of synergy and redundancy.

Old news, but interesting: the US National Security Agency (NSA) announced some months ago that it was suspending funding to its Mathematical Sciences Program. The announcement begins by phrasing it as a temporary suspension—

…[we] will be unable to fund any new proposals during FY2017 (i.e. Oct. 1, 2016–Sept. 30, 2017)

—but by the end, sounds resigned to a more permanent fate:

We thank the mathematics community and especially the American Mathematical Society for its interest and support over the years.

We’ve discussed this grant programme before on this blog.

The NSA is said to be the largest employer of mathematicians in the world, and has been under political pressure for obvious reasons over the last few years, so it’s interesting that it cut this programme. Its British equivalent, GCHQ, is doing the opposite, expanding its mathematics grants aggressively. But still, GCHQ consistently refuses to engage in any kind of adult, evidence-based discussion with the mathematical community on what the effect of its actions on society might actually be.

Because it is:

"... Groups of dark brown streaks have been photographed by the Mars Reconnaissance Orbiter on melting pinkish sand dunes covered with light frost..."

Author: Peter Stern

My buddy Josh Vekhter is visiting from his Ph.D. program in computer science and told me about a couple of incredibly creepy technological advances that will soon make our previous experience of fake news seem quaint.

First, there’s a way to edit someone’s speech:

Next, there’s a way to edit a video to insert whatever facial expression you want (I blame Pixar on this one):

Put those two technologies together and you’ve got Trump and Putin having an entirely fictitious but believable conversation on video.

Reposted from 2016 to add this awesome marble run choreographed to music:


With a hat tip to Miss C at Neatorama.

Reposted from January to add this even better one:


 There is an explanation of some of the mechanics at Neatorama.

I’ve just come back from the annual conference of the British Ecological Society in Liverpool. For several years I’ve had a side-interest in ecology, but I’d never spent time with a really large group of ecologists before, and it taught me some things. Here goes:

1. Size and scale. Michael Reed memorably observed that the American Mathematical Society is about the same size as the American Society for Nephrology, “and that’s just the kidney”. Simply put: not many people care about mathematics.

   The British Ecological Society (BES) meeting had 1200 participants, which is about ten times bigger than the annual international category theory meeting, and still only a fraction of the size of the conference run by the Ecological Society of America. You may reply that the US Joint Mathematics Meetings attract about 7000 participants; but as Reed pointed out (under the heading “Most of Science is Biology”), the Society for Neuroscience gets about 30,000. Even at the BES meeting in our small country, there were nearly 600 talks, 70 special sessions, and 220 posters. In the parallel sessions, you had a choice of 12 talks to go to at any given moment in time.

2. Concision. Almost all talks were 12 minutes, with 3 minutes for questions. You cannot, of course, say much in that time.

   With so many people attending and wanting to speak, it’s understandable that the culture has evolved this way. And I have to say, it’s very nice that if you choose to attend a talk and swiftly discover that you chose badly, you’ve only lost 15 minutes.

   But there are many critiques of enforced brevity, including from some very distinguished academics. It’s traditionally held that the most prestigious journals in all of science are Nature and Science, and in both cases the standard length of an article is only about three pages. The style of such papers is ludicrously condensed, and from my outsider’s point of view I gather that there’s something of a backlash against Nature and Science, with less constipated publications gaining ground in people’s mental ranking systems. When science is condensed too much, it takes on the character of a sales pitch.

   This is part of a wider phenomenon of destructive competition for attention. For instance, almost all interviews on TV news programmes are under ten minutes, and most are under five, with much of that taken up by the interviewer talking. The very design favours sloganeering and excludes all points that are too novel or controversial to explain in a couple of sentences. (The link is to a video of Noam Chomsky, who makes this point very effectively.) Not all arguments can be expressed to a general audience in a few minutes, as every mathematician knows.

3. The pleasure of introductions. Many ecologists study one particular natural system, and often the first few minutes of their talks are a delight. You learn something new and amazing about fungi or beavers or the weird relationships between beetles and ants. Did you know that orangutans spend 80% of the day resting in their nests? Or that if you give a young orangutan some branches, he or she will instinctively start to weave them together in a nest-like fashion, as an innate urge that exists whether or not they’ve been taught how to do it? I didn’t.

   

4. Interdisciplinarity. I’ve written before about the amazing interdisciplinarity of biologists. It seems to be ingrained in the intellectual culture that you need people who know stuff you don’t know, obviously! And that culture just isn’t present within mathematics, at least not to anything like the same extent.

   For instance, this afternoon I went to a talk about the diversity of microbiomes. The speaker pointed out that for what she was doing, you needed expertise in biology, chemistry, and informatics. She was unusual in actually spelling it out and spending time talking about it. Most of the time, speakers moved seamlessly from ecology to statistics to computation (typically involving processing of large amounts of DNA sequence data), without making a big deal of it.

   But there’s a byproduct of interdisciplinarity that troubles my mathematical soul:

5. The off-the-shelf culture. Some of the speakers bowled me over with their energy, vision, tenacity, and positive outlook. But no one’s superhuman, so it’s inevitable that if your work involves serious aspects of multiple disciplines, you’re probably not going to look into everything profoundly. Or more bluntly: if you need some technique from subject X and you know nothing about subject X, you’re probably just going to use whatever technique everybody else uses.

   The ultimate reason why I ended up at this conference is that I’m interested in the quantification of biological diversity. So, much of the time I chose to go to talks that had the word “diversity” in the title, just to see what measure of diversity was used by actual practising ecologists.

   It wasn’t very surprising that almost all the time, as far as I could tell, there was no apparent examination of what the measures actually measured. They simply used whatever measure was predominant in the field.

   Now, I need to temper that with the reminder that the talks are ultra-short, with no time for subtleties. But still, when I asked one speaker why he chose the measure that he chose, the answer was that it’s simply what everyone else uses. And I can’t really point a finger of blame. He wasn’t a mathematician, any more than I’m an ecologist.

6. The lack of theory. If this conference was representative of ecology, the large majority of ecologists study some specific system. By “system” I mean something like European hedgerow ecology, or Andean fungal ecology, or the impact of heatwaves on certain types of seaweed.

   This is, let me be clear, not a bad thing. Orders of magnitude more people care about seaweed than nn-categories. But still, I was surprised by the sheer niche-ness of general theory in the context of ecology as a whole. A group of us are working on a system of diversity measures that are general in a mathematician’s sense; they effortlessly take in such examples as human demography, tropical forestry, epidemiology, and resistance to antibiotics. This didn’t seem like that big a deal to me previously — it’s just the bog-standard generality of mathematics. But after this week, I can see that from many ecologists’ eyes, it may seem insanely general.

   Actually, the most big-picture talks I saw were very unmathematical. They were, in fact, about policy and the future of humanity. I’m not being flippant:

7. Unabashed politics. Mathematics is about an idealized world of imagination. Ecology is about our one and only natural world — one that we happen to be altering at an absolutely unprecedented rate. Words like “Brexit” and “Trump” came up dozens of times in the conference talks, and not in a tittery jocular way. The real decisions of people with real political power will have real, irreversible effect in the real world.

   Once again, this brought home to me that mathematics is not like (the rest of) science.

   It’s not just that we don’t have labs or experiments or hypothesis testing (at least, not in the same way). It’s that we can do mathematics in complete isolation from the realities of the world that human beings have made.

   We don’t have to think about deforestation or international greenhouse gas treaties or even local fishery byelaws. We might worry about the applications of mathematics — parasitic investment banks or deadly weapons or governments surveilling and controlling their citizens — but we can actually do mathematics in lamb-like innocence.

   On the other hand, for large parts of ecology, the political reality is an integral consideration.

   I saw some excellent talks, especially from Georgina Mace and Hugh Possingham, on policy and influencing governments. Possingham was talking about saving Portugal-sized areas of Australia from industrial destruction. (His advice for scientists engaging with governments: “Turn up. Have purpose. Maintain autonomy.”) Mace spoke on what are quite possibly the biggest threats to the entire planet: climate change, floods and heatwaves, population growth, and fragmentation and loss of habitats.

   It’s inspiring to see senior scientists being unafraid to repeat basic truths to those in power, to gather the available evidence and make broad estimates with much less than 100% of the data that one might wish for, in order to push changes that will actually improve human and other animal lives.

I try to stay out of politics on this website. This post is not mainly about politics. It’s a call to action. We’re trying to do something rather simple and clearly worthwhile. We’re trying to create backups of US government climate data.

The background is, of course, political. Many signs point to a dramatic change in US climate policy:

• Oliver Milman, Trump’s transition: sceptics guide every agency dealing with climate change, The Guardian, 12 December 2016.

So, scientists are now backing up large amounts of climate data, just in case the Trump administration tries to delete it after he takes office on January 20th:

• Brady Dennis, Scientists are frantically copying U.S. climate data, fearing it might vanish under Trump, Washington Post, 13 December 2016.

Of course saving the data publicly available on US government sites is not nearly as good as keeping climate programs fully funded! New data is coming in all the time from satellites and other sources. We need it—and we need the experts who understand it.

Also, it’s possible that the Trump administration won’t go so far as trying to delete big climate science databases. Still, I think it can’t be a bad thing to have backups. Or as my mother always said: better safe than sorry!

Quoting the Washington Post article:

Alarmed that decades of crucial climate measurements could vanish under a hostile Trump administration, scientists have begun a feverish attempt to copy reams of government data onto independent servers in hopes of safeguarding it from any political interference.

The efforts include a “guerrilla archiving” event in Toronto, where experts will copy irreplaceable public data, meetings at the University of Pennsylvania focused on how to download as much federal data as possible in the coming weeks, and a collaboration of scientists and database experts who are compiling an online site to harbor scientific information.

“Something that seemed a little paranoid to me before all of a sudden seems potentially realistic, or at least something you’d want to hedge against,” said Nick Santos, an environmental researcher at the University of California at Davis, who over the weekend began copying government climate data onto a nongovernment server, where it will remain available to the public. “Doing this can only be a good thing. Hopefully they leave everything in place. But if not, we’re planning for that.”

[…]

“What are the most important .gov climate assets?” Eric Holthaus, a meteorologist and self-proclaimed “climate hawk,” tweeted from his Arizona home Saturday evening. “Scientists: Do you have a US .gov climate database that you don’t want to see disappear?”

Within hours, responses flooded in from around the country. Scientists added links to dozens of government databases to a Google spreadsheet. Investors offered to help fund efforts to copy and safeguard key climate data. Lawyers offered pro bono legal help. Database experts offered to help organize mountains of data and to house it with free server space. In California, Santos began building an online repository to “make sure these data sets remain freely and broadly accessible.”

In Philadelphia, researchers at the University of Pennsylvania, along with members of groups such as Open Data Philly and the software company Azavea, have been meeting to figure out ways to harvest and store important data sets.

At the University of Toronto this weekend, researchers are holding what they call a “guerrilla archiving” event to catalogue key federal environmental data ahead of Trump’s inauguration. The event “is focused on preserving information and data from the Environmental Protection Agency, which has programs and data at high risk of being removed from online public access or even deleted,” the organizers said. “This includes climate change, water, air, toxics programs.”

The event is part of a broader effort to help San Francisco-based Internet Archive with its End of Term 2016 project, an effort by university, government and nonprofit officials to find and archive valuable pages on federal websites. The project has existed through several presidential transitions.

I hope that small “guerilla archiving” efforts will be dwarfed by more systematic work, because it’s crucial that databases be copied along with all relevant metadata—and some sort of cryptographic certificate of authenticity, if possible. However, getting lots of people involved is bound to be a good thing, politically speaking.

If you have good computer skills, good understanding of databases, or lots of storage space, please get involved. Efforts are being coordinated by Barbara Wiggin and others at the Data Refuge Project:

• PPEHLab (Penn Program in the Environmental Humanities), DataRefuge.

You can contact them at DataRefuge@ppehlab.org. Nick Santos is also involved, and if you want to get “more plugged into the project” you can contact him here. They are trying to build a climate database mirror website here:

• Climate Mirror.

At the help form on this website you can nominate a dataset for rescue, claim a dataset to rescue, let them know about a data rescue event, or help in some other way (which you must specify).

PPEHLab and Penn Libraries are organizing a data rescue event this Thursday:

• PPEHLab, DataRefuge meeting, 14 December 2016.

At the American Geophysical Union meeting in San Francisco, where more than 20,000 earth and climate scientists gather from around the world, there was a public demonstration today starting at 1:30 PST:

• Rally to stand up for science, 13 December 2016.

And the “guerilla archiving” hackathon in Toronto is this Saturday—see below. If you know people with good computer skills in Toronto, get them to check it out!

To follow progress, also read Eric Holthaus’s tweets and replies here:

• Eric Holthaus.

Guerrilla archiving in Toronto

Here are details on this:

Guerrilla Archiving Hackathon

Date: 10am-4pm, December 17, 2016

Location: Bissell Building, 4th Floor, 140 St. George St. University of Toronto

RSVP and up-to-date information: Guerilla archiving: saving environmental data from Trump.

Bring: laptops, power bars, and snacks. Coffee and pizza provided.

This event collaborates with the Internet Archive’s End of Term 2016 project, which seeks to archive the federal online pages and data that are in danger of disappearing during the Trump administration. Our event is focused on preserving information and data from the Environmental Protection Agency, which has programs and data at high risk of being removed from online public access or even deleted. This includes climate change, water, air, toxics programs. This project is urgent because the Trump transition team has identified the EPA and other environmental programs as priorities for the chopping block.

The Internet Archive is a San Francisco-based nonprofit digital library which aims at preserving and making universally accessible knowledge. Its End of Term web archive captures and saves U.S. Government websites that are at risk of changing or disappearing altogether during government transitions. The Internet Archive has asked volunteers to help select and organize information that will be preserved before the Trump transition.

End of Term web archive: http://eotarchive.cdlib.org/2016.html

New York Times article: “Harvesting Government History, One Web Page at a Time”

Activities:

Identifying endangered programs and data

Seeding the End of Term webcrawler with priority URLs

Identifying and mapping the location of inaccessible environmental databases

Hacking scripts to make accessible to the webcrawler hard to reach databases.

Building a toolkit so that other groups can hold similar events

Skills needed: We need all kinds of people — and that means you!

People who can locate relevant webpages for the Internet Archive’s webcrawler

People who can identify data targeted for deletion by the Trump transition team and the organizations they work with

People with knowledge of government websites and information, including the EPA

People with library and archive skills

People who are good at navigating databases

People interested in mapping where inaccessible data is located at the EPA

Hackers to figure out how to extract data and URLs from databases (in a way that Internet Archive can use)

People with good organization and communication skills

People interested in creating a toolkit for reproducing similar events

Contacts: michelle.murphy@utoronto.ca, p.keilty@utoronto.ca

The post The Revolution Has Begun: Beyond Meat appeared first on Marginal REVOLUTION.

Memory researchers have shone light into a cognitive limbo. A new memory—the name of someone you've just met, for example—is held for seconds in so-called working memory, as your brain's neurons continue to fire. If the person is important to you, the name will over a few days enter your long-term memory, preserved by permanently altered neural connections. But where does it go during the in-between hours, when it has left your standard working memory and is not yet embedded in long-term memory? To figure this out, a research team resurrects memories from this limbo. Their observations point to a new form of working memory, which they dub prioritized long-term memory, that exists without elevated neural activity. Consistent with other recent work, the study suggests that information can somehow be held among the synapses that connect neurons, even after conventional working memory has faded. This new memory state could have a range of practical implications, from helping college students learn more efficiently to assisting people with memory-related neurological conditions such as amnesia, epilepsy, and schizophrenia. Author: Jessica Boddy

Transplanted embryonic neurons integrate into adult neocortical circuits

Nature 539, 7628 (2016). doi:10.1038/nature20113

Authors: Susanne Falkner, Sofia Grade, Leda Dimou, Karl-Klaus Conzelmann, Tobias Bonhoeffer, Magdalena Götz & Mark Hübener

The ability of the adult mammalian brain to compensate for neuronal loss caused by injury or disease is very limited. Transplantation aims to replace lost neurons, but the extent to which new neurons can integrate into existing circuits is unknown. Here, using chronic in vivo

A cannabinoid link between mitochondria and memory

Nature 539, 7630 (2016). doi:10.1038/nature20127

Authors: Etienne Hebert-Chatelain, Tifany Desprez, Román Serrat, Luigi Bellocchio, Edgar Soria-Gomez, Arnau Busquets-Garcia, Antonio Christian Pagano Zottola, Anna Delamarre, Astrid Cannich, Peggy Vincent, Marjorie Varilh, Laurie M. Robin, Geoffrey Terral, M. Dolores García-Fernández, Michelangelo Colavita, Wilfrid Mazier, Filippo Drago, Nagore Puente, Leire Reguero, Izaskun Elezgarai, Jean-William Dupuy, Daniela Cota, Maria-Luz Lopez-Rodriguez, Gabriel Barreda-Gómez, Federico Massa, Pedro Grandes, Giovanni Bénard & Giovanni Marsicano

Cellular activity in the brain depends on the high energetic support provided by mitochondria, the cell organelles which use energy sources to generate ATP. Acute cannabinoid intoxication induces amnesia in humans and animals, and the activation of type-1 cannabinoid receptors present at brain mitochondria membranes (mtCB1) can directly alter mitochondrial energetic activity. Although the pathological impact of chronic mitochondrial dysfunctions in the brain is well established, the involvement of acute modulation of mitochondrial activity in high brain functions, including learning and memory, is unknown. Here, we show that acute cannabinoid-induced memory impairment in mice requires activation of hippocampal mtCB1 receptors. Genetic exclusion of CB1 receptors from hippocampal mitochondria prevents cannabinoid-induced reduction of mitochondrial mobility, synaptic transmission and memory formation. mtCB1 receptors signal through intra-mitochondrial Gαi protein activation and consequent inhibition of soluble-adenylyl cyclase (sAC). The resulting inhibition of protein kinase A (PKA)-dependent phosphorylation of specific subunits of the mitochondrial electron transport system eventually leads to decreased cellular respiration. Hippocampal inhibition of sAC activity or manipulation of intra-mitochondrial PKA signalling or phosphorylation of the Complex I subunit NDUFS2 inhibit bioenergetic and amnesic effects of cannabinoids. Thus, the G protein-coupled mtCB1 receptors regulate memory processes via modulation of mitochondrial energy metabolism. By directly linking mitochondrial activity to memory formation, these data reveal that bioenergetic processes are primary acute regulators of cognitive functions.

The need to breathe links the mammalian olfactory system inextricably to the respiratory rhythms that draw air through the nose. In rodents and other small animals, slow oscillations of local field potential activity are driven at the rate of breathing (~2–12 Hz) in olfactory bulb and cortex, and faster oscillatory bursts are coupled to specific phases of the respiratory cycle. These dynamic rhythms are thought to regulate cortical excitability and coordinate network interactions, helping to shape olfactory coding, memory, and behavior. However, while respiratory oscillations are a ubiquitous hallmark of olfactory system function in animals, direct evidence for such patterns is lacking in humans. In this study, we acquired intracranial EEG data from rare patients (Ps) with medically refractory epilepsy, enabling us to test the hypothesis that cortical oscillatory activity would be entrained to the human respiratory cycle, albeit at the much slower rhythm of ~0.16–0.33 Hz. Our results reveal that natural breathing synchronizes electrical activity in human piriform (olfactory) cortex, as well as in limbic-related brain areas, including amygdala and hippocampus. Notably, oscillatory power peaked during inspiration and dissipated when breathing was diverted from nose to mouth. Parallel behavioral experiments showed that breathing phase enhances fear discrimination and memory retrieval. Our findings provide a unique framework for understanding the pivotal role of nasal breathing in coordinating neuronal oscillations to support stimulus processing and behavior.

SIGNIFICANCE STATEMENT Animal studies have long shown that olfactory oscillatory activity emerges in line with the natural rhythm of breathing, even in the absence of an odor stimulus. Whether the breathing cycle induces cortical oscillations in the human brain is poorly understood. In this study, we collected intracranial EEG data from rare patients with medically intractable epilepsy, and found evidence for respiratory entrainment of local field potential activity in human piriform cortex, amygdala, and hippocampus. These effects diminished when breathing was diverted to the mouth, highlighting the importance of nasal airflow for generating respiratory oscillations. Finally, behavioral data in healthy subjects suggest that breathing phase systematically influences cognitive tasks related to amygdala and hippocampal functions.

While any particular move could be a boneheaded one which could set us on the path to Armageddon, I actually think the general concept of Trump blowing up our diplomatic protocols is fine. No I am not here to praise Trump. Likely he will set us on the path to Armageddon. Still I've long seen the way various long-established "rules" of doing thing seem to serve little purpose other than to make sure that the deep state maintains its control of the executive.

Some of our diplomatic niceties are stupid, though I do understand they exist for good reasons, even if they exist for bad ones, as I suspect, also, too.

Update and Action Item: Just since late this afternoon, the Jill Stein campaign has already raised more than $1 million toward requesting hand recounts in Pennsylvania, Michigan, and Wisconsin.  Their target is $6-7 million.  I just donated what I could; if you agree with this post, then please do the same.  It doesn’t matter at this point if you disagree with Stein, or even (like me) think she shouldn’t have run: the goal is just to get a recount to happen before the deadline expires.

Another Update (11/24): In an amazing demonstration of the power of online fundraising, the Stein campaign has already, in less than 24 hours, raised the $2.5 million needed to fund a recount in Wisconsin.  Now they’re working on Pennsylvania and Michigan.  Amusing that Stein seems finally to have found a winning cause: Hillary!  (“Fighting for Hillary even when Hillary won’t fight for herself.”)  Again: please donate here.

Third Update (11/25):  The recount is on is Wisconsin!  The Stein campaign hasn’t yet filed in Pennsylvania or Michigan, but will do so next.  So, all the commenters who came here to explain to me that this was a scam, no judge would it allow it to go forward, etc.: please update your priors.  And next time, if you won’t listen to me, at least listen to Alex Halderman…

---

This will probably be my last election-related post.  After this (assuming, of course, that the effort I’m writing about fails…), I plan to encase myself in a bubble, stop reading news, and go back to thinking about quantum lower bounds, as if we still lived in a world where it made sense to do so.  But this is important.

As many of you have probably seen, several of the US’s top computer security experts, including my former MIT colleague Ron Rivest and my childhood friend Alex Halderman, have publicly urged that an audit of the US election take place.  But time is quickly running out.  If, for example, the Clinton campaign were to request a hand recount, the deadlines would be this Friday in Wisconsin, Monday in Pennsylvania, and next Wednesday in Michigan.  So far, alas, the Clinton campaign seems to have shown little interest, which would leave it to one of the third-party candidates to request a recount (they have the legal right too, if they can come up with the money for it).  In the meantime, I urge everyone to sign a petition demanding an audit.

For me, the key point is this: given the proven insecurity of electronic voting machines, an audit of paper ballots ought to be completely routine, even if there weren’t the slightest grounds for suspicion.  In this particular case, of course, we know for a fact (!!) that Russian intelligence was engaging in cyber-warfare to influence the US election.  We also know that Russia has both the will and the technological ability to tamper with foreign elections using vote-stealing malware—indeed, it nearly succeeded in doing so in Ukraine’s 2014 election.  Finally, we know that Trump, despite losing the popular vote, surprised just about everyone by outperforming his polls in three crucial swing states—and that within those states, Trump did systematically better in counties that relied on electronic voting machines than in counties that used scanners and paper ballots.

Nate Silver has tweeted that he sees no evidence of foul play, since the discrepancy disappears once you control for the education level of the counties (for more, see this FiveThirtyEight article).

But that’s the thing.  In a sane world, skeptics wouldn’t need to present statistical proof of foul play in order to trigger a hand count.  For if enemy actors know that, in practice, hand counts are never going to happen, then they’re free to be completely brazen in tampering with the childishly-insecure electronic voting machines themselves.  If no one ever looks at them, then the paper records might as well not exist.

Would anyone in the 1950s or 60s have believed that, a half-century hence, Russia actually would acquire the terrifying power over the US that the right-wing Cold Warriors once hyperventilated about—sometimes choosing to exercise that power, sometimes not—and that 2016’s conservatives would either shrug or welcome the development, while the only people who wanted to take reasonable precautions were a few rabble-rousing professors and activists?

Fate has decided that we should live in a branch of the wavefunction where the worst triumph by flaunting their terribleness and where nothing makes sense.  But however infinitesimal the chances anyone will listen, we should still insist that the sensible things be done—if nothing else, then simply as a way to maintain our own mental connection to the world of sense.

Happy Thanksgiving.

Yesterday I heard a segment on WNYC on the effort to decriminalize box cutters in New York State. I guess it’s up to Governor Cuomo to sign it into law.

During the segment we hear a Latino man who tells his story: he was found by cops to be in possession of a box cutter and spent 10 days in Rikers. He works in construction and having a box cutter is literally a requirement for his job. His point was that the law made it too easy for people with box cutters to end up unfairly in jail.

It made me wonder, who actually gets arrested for possession of box cutters? I’d really like to know. I’m guessing it’s not a random selection of “people with box cutters.” Indeed I’m pretty sure this is almost never a primary reason to arrest a white person at all, man or woman. It likely only happens to people after being stopped and frisked for no particular good reason, and that’s much more likely to happen to minority men. I could be wrong but I’d like to see those stats.

It’s part of a larger statistical question that I think we should tackle: what is the racial discrepancy in arrest rates for other crimes, versus the population that actually commits those other crimes? I know for pot possession it’s extremely biased against blacks:

On the other end of the spectrum, I’d guess murder arrests are pretty equally distributed by race relative to the murdering population. But there’s all kinds of crimes in between, and I’d like some idea of how racially biased the arrests all are. In the case of box cutters, I’m guessing the bias is even stronger than for pot possession.

If w had this data, a statistician could mock up a way to “account for” racial biases in police practices for a given crime record, like we do in polling or any other kind of statistical analysis.

Not that it’s easy to collect; this is honestly some of the most difficult “ground truth” data you can imagine, almost as hard as money in politics. Still, it’s interesting to think about.

Found in Croatia.  Photo credit Vedran Glavan/Barcroft, via The Telegraph.

Update (Nov. 10): In the wake of the US’s authoritarian takeover, I will sadly understand if foreign students and postdocs no longer wish to study in the US, or if foreign researchers no longer wish to enter the US even for conferences and visits. After all, I wouldn’t feel safe in Erdogan’s Turkey or the Mullahs’ Iran. In any case, I predict that the US’s scientific influence will now start to wane, as top researchers from elsewhere find ways to route around us.

I make just one request: if you do come to the US (as I selfishly hope you will), please don’t avoid places like Austin just because they look on the map like they’re in a sea of red. To understand what’s going on, you need to look at the detailed county-by-county results, which show that even in “red” states, most cities went overwhelmingly for Clinton, while even in “blue” states like New York, most rural areas went for Trump. Here’s Texas, for example (Austin was 66% Clinton, 27% Trump).

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I’m ashamed of my country and terrified about the future.  When Bush took power in 2000, I was depressed for weeks, but I didn’t feel like I do now, like a fourth-generation refugee in the United States—like someone who happens to have been born here and will presumably continue to live here, unless and until it starts to become unsafe for academics, or Jews, or people who publicly criticize Trump, at which time I guess we’ll pack up and go somewhere else (assuming there still is a somewhere else).

If I ever missed the danger and excitement that so many European scientists and mathematicians felt in the 1930s, that sense of trying to pursue the truth even in the shadow of an aggressive and unironic evil—OK, I can cross that off the list.  Since I was seven years old or so, I’ve been obsessed by the realization that there are no guardrails that prevent human beings from choosing the worst, that all the adults who soothingly reassure you that “everything always works out okay in the end” are full of it.  Now I get to live through it instead of just reading about it in history books and having nightmares.

If James Comey hadn’t cast what turned out to be utterly unfounded suspicion over Hillary during the height of early voting, maybe the outcome would’ve been different.  If young and poor and minority voters in Wisconsin and North Carolina and elsewhere hadn’t been effectively disenfranchised through huge lines and strategic voter ID laws and closures of polling places, maybe the outcome would’ve been different.  If Russia and WikiLeaks hadn’t interfered by hacking one side and not the other, maybe the outcome would’ve been different.  For that matter, if Russia or some other power hacked the trivially-hackable electronic voting machines that lack paper trails—machines that something like a third of American voters still used this election—there’s an excellent chance we’d never find out.

But in some sense, all of that is beside the point.  For take all of it away, and Trump still would’ve at least come within a few terrifying points of winning—and as Scott Alexander rightly stresses, whatever horrible things are true about the American electorate today, would still have been true had Hillary eked out a narrow win.  It’s just that now we all get to enjoy the consequences of ½±ε of the country’s horrible values.

There is no silver lining.  There’s nothing good about this.

My immediate problem is that, this afternoon, I’m supposed to give a major physics colloquium at UT.  The title?  “Quantum Supremacy.”  That term, which had given me so much comedic mileage through the long campaign season (“will I disavow support from quantum supremacists?  I’ll keep you in suspense about it…” ), now just seems dark and horrible, a weight around my neck.  Yet, distracted and sleep-deprived and humor-deprived though I am, I’ve decided to power through and give the talk.  Why?  Because Steven Weinberg says he still wants to hear it.

I see no particular reason to revise anything I’ve said on this blog about the election, except perhaps for my uncritical quoting of all the analyses and prediction markets that gave Trump a small (but still, I stressed, much too high) probability of winning.

I stand by my contempt for the Electoral College, and my advocacy for vote-swapping.  The fact that vote-swapping once again failed doesn’t mean it was a bad idea; on the contrary, it means that we didn’t do enough.

I stand by my criticism of some of the excesses of the social justice movement, which seem to me to have played some role in spawning the predictable backlash whose horrific results the world now sees.

Lastly, I stand by what I said about the centrality of Enlightenment norms and values, and of civil discourse even with those with whom we disagree, to my own rejection of Trumpism.

On the other hand, the Trump supporters who are leaving me anonymous taunting comments can go elsewhere.  On this day, I think a wholly appropriate Enlightenment response to them is “fuck you.”

The post Solve for the equilibrium are British people really like this? appeared first on Marginal REVOLUTION.

A system with many degrees of freedom can be characterized by a covariance matrix; principal components analysis (PCA) focuses on the eigenvalues of this matrix, hoping to find a lower dimensional description. But when the spectrum is nearly continuous, any distinction between components that we keep and those that we ignore becomes arbitrary; it then is natural to ask what happens as we vary this arbitrary cutoff. We argue that this problem is analogous to the momentum shell renormalization group (RG). Following this analogy, we can define relevant and irrelevant operators, where the role of dimensionality is played by properties of the eigenvalue density. These results also suggest an approach to the analysis of real data. As an example, we study neural activity in the vertebrate retina as it responds to naturalistic movies, and find evidence of behavior controlled by a nontrivial fixed point. Applied to financial data, our analysis separates modes dominated by sampling noise from a smaller but still macroscopic number of modes described by a non--Gaussian distribution.

A century-old theoretical model of magnetism is giving rise to a hybrid computer, part classical and part quantum, that may capable of solving problems that overwhelm conventional computers. The so-called Ising machine, described in 100-bit and 2000-bit versions in two reports this week in Science, could tackle optimization problems that require finding the best solution among myriad possibilities, such as predicting how a protein will fold or allotting bandwidth in cellular communications networks. The machines take their name from the Ising model, which was developed in 1920 in an attempt to explain magnetism. Curiously, many optimization problems can be mapped onto the Ising model. Now, two overlapping groups at Stanford University in Palo Alto, California, and at NTT Basic Research Laboratories in Atsugi, Japan, have developed optical machines specifically designed to solve the model, at least approximately. Developers hope Ising machines may soon replace or aid conventional computers for some applications, although some researchers note it is not yet clear that the new machines can best ordinary computers. Author: Adrian Cho

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