Friday, May 31, 2013
Damn straight. I have pulled my share of things too, of course. For example, I need to go dig old my exam instructions that allow the use of 'a note from your mother' and the question about mystery meat with Poisson-distributed things in it. (One of the students actually submitted a note from her mother. It include threats against both Lloydies and the Los Angeles Dodgers. There was also a comment about the potential health problems caused by generating functions.) (Tip of the cap to Sammy Kline --- and, of course, to Katie Noyes Rogstad and her mother.)
Wednesday, May 29, 2013
Apparently, male chess players make riskier opening moves when they are playing attractive female players. (Tip of the cap to Annals of Improbable Research.)
Another of my papers is now out in final form (with a volume, issue number, page numbers, and everything). This article appears in the first issue of Journal of Complex Networks (of which I am an associate editor), so of course the volume number and the issue number are both 1. Naturally, that was still left as a placeholder when the journal posted the article online before the official assignment of that information. :) Additionally, this paper has the largest number of authors of any of my papers. Anyway, here are the details. Title: Dynamic Network Centrality Summarizes Learning in the Human Brain Authors: Alexander V. Mantzaris, Danielle S. Bassett, Nicholas F. Wymbs, Ernesto Estrada, Mason A. Porter, Peter J. Mucha, Scott T. Grafton, and Desmond J. Higham Abstract: We study functional activity in the human brain using functional magnetic resonance imaging and recently developed tools from network science. The data arise from the performance of a simple behavioural motor learning task. Unsupervised clustering of subjects with respect to similarity of net- work activity measured over 3 days of practice produces significant evidence of ‘learning’, in the sense that subjects typically move between clusters (of subjects whose dynamics are similar) as time progresses. However, the high dimensionality and time-dependent nature of the data makes it difficult to explain which brain regions are driving this distinction. Using network centrality measures that respect the arrow of time, we express the data in an extremely compact form that characterizes the aggregate activity of each brain region in each experiment using a single coefficient, while reproducing information about learning that was discovered using the full data set. This compact summary allows key brain regions contributing to centrality to be visualized and interpreted. We thereby provide a proof of principle for the use of recently proposed dynamic centrality measures on temporal network data in neuroscience.
Monday, May 27, 2013
Sunday, May 26, 2013
Wednesday, May 22, 2013
A very cool test was given in a Behavioral Ecology class at UCLA. It sounds like it was a great learning experience for the students, and of course this story makes me think of a certain exam I once took in Philosophy of Probability. In both situations, the lessons from the course itself played center stage in the exam-taking strategy. (Tip of the cap to Jasvir Grewal.)
Friday, May 17, 2013
Tomorrow, I am heading off to Snowbird once again for the SIAM Conference on Applications of Dynamical Systems. The regulars call this the "Snowbird Conference". Since my first Snowbird conference in 1999, the only one I have missed is the one in 2005. This is my home conference.
Tuesday, May 14, 2013
That is the first highlight listed for this paper, which is called A mathematical model of "Gone with the Wind". (Tip of the cap to Jesús Cuevas Maraver.)
Monday, May 13, 2013
Yes, really. And this new paper (which is called Child Allowances, Fertility, and Chaotic Dynamics) claims to prove this in a model using rigorous mathematics. Obviously, this depends on how much one believes the model. The paper is written in a rather abstract manner, so clearly I am skeptical. There are some "awesome" things in the article, however. For one thing, I am not sure how chaotic dynamics is important to the problem at hand (as opposed to just in the model the authors happen to study), but chaos is genuinely important in other applications, so who knows? Another big "win" is the use of the term "allowance". What the authors have in mind is the number of children that one is allowed to have, but the other (unintended) interpretation of parents giving a child an "allowance" with which to buy things is what truly makes this a thing of beauty. I didn't look carefully enough at the mathematics itself, so I have no opinion on that. Rather, I am viewing this through my mathematical modelling lens, and I think it is "awesome" from that perspective. And the article title is truly a thing of beauty! This is the type of article that makes me both laugh and cry --- and I think that there might be an Ig Nobel Prize in store for the authors of this paper.
Saturday, May 11, 2013
In the print version of Daily Info at a local cafe, I noticed the following fantastic caveat below the cinema listing for Iron Man 3: "Not a follow-up to The Iron Lady." (I need to go there with my camera tomorrow so that I can get a picture of this. Sadly, the online versions of this document don't seem to include this warning --- or at least I was unable to find one that does. The current issue is 8407. I think the one I want is number 8406.)
Friday, May 10, 2013
Aric Hagberg, Cosma Shalizi, and Aaron Clauset have just created the Zachary Karate Club Club (or Award, if you prefer). Membership in this exclusive Club is awarded to "the first scientist at any conference on networks who uses Zachary's karate club". Here is Aaron Clauset's tweet announcing the inception of the Club. The inaugural inductee was Cris Moore, who is currently in possession of the coveted trophy representing his induction. (Naturally, karate is depicted on this trophy.) This trophy --- and perhaps other, similar, ones --- will be passed along at subsequent conferences and workshops on networks. (Tip of the cap to Aaron for his e-mail letting me know about this.)
I got to meet the members of the band OMD on Monday at the VIP part a few hours before their concert. I got them to sign the novel that I brought with me to read (as that is all that I had with me for them to sign). (Hopefully you can see the other pictures. I have thus far failed to find a public link to the album that I posted on Facebook. For now, I am linking to the picture I took with the band.)
Thursday, May 09, 2013
Actually, the surface of penguins' bodies are colder than the sub-zero temperatures of their surroundings! By the way, the purpose of this blog entry is merely to correct a glaring deficiency in the article to which I link: namely, how on earth could its authors write this article without making an allusion to Foreigner? (Tip of the cap to I Fucking Love Science.)
Wednesday, May 08, 2013
Here is a map of the London Underground (aka, the Tube) with an interesting twist: all of the stations are presented using anagrams of their actual names. (Tip of the cap to Alan Champneys.)
Tuesday, May 07, 2013
Sunday, May 05, 2013
I am currently revising a paper in which I need to use both the terms topology and geometry in adjective form on many occasions (and as a contrast to each other). This poses an interest expository conundrum: both "geometric" and geometrical" are correct adjectives for geometry, although the former is a good deal more common in mathematics than the latter. Nevertheless, both are correct, and you can find both used in the Wikipedia entry on geometry to which I linked above. However, I have never seen the word "topologic" used (as "topological" seems to be used all of the time), though at least one online dictionary claims that it is technically correct. The expository issue is that it is rather awkward to use "topological" yet "geometric", so the best solution appears to be to use the term "geometrical", even though it is less standard and seems a bit less nice when considered on its own. (Part of the issue is that certain things, like "geometric series", appear to almost always use the other form of the word.) I have decided that I would like to get to the bottom of this --- because I find this interesting --- so I decided to e-mail my colleague Peter Neumann, who has a keen interest in the history of mathematics and who I judged most likely among all of my Mathematical Institute colleagues to know the history behind how the adjective forms of geometry and topology developed in different ways. (One possibility that has crossed my mind was because of the "ology" ending in "topology" but not the other, but I have not tried to check whether that difference is worth pursuing to try to figure out what's going on.) Peter responded as follows: What a very interesting question. French has just the one form topologique, g\'eom\'etrique, arithm\'etique, alg\'ebrique. Similarly, German has just one form topologisch, geometrisch, arithmetisch, algebraisch. Yes, in English, most of these words used adjectivally have two forms. I think that topological is the only one to have just one. All the others can be geometric or geometrical, arithmetic or arithmetical, algebraic or algebraical (though this last is very uncommon now). I suspect that the -al forms may have been created in the 19th Century by people like Cayley, Sylvester, Hamilton, but that is a pure guess. I'll copy this to Alan Hughes of the Oxford English Dictionary. He may well know. We do use geometrical, I think, in phrases like `geometrical drawing', geometrical argument', `geometrical proof'. But the geometric mean could not possibly be the geometrical mean, could it? So that is where we now stand. Peter has cc'ed a person from the Oxford English Dictionary, who I hope will be able to shed some further light on the subject. (If Alan doesn't know or can't point out someone else to ask, I will try to figure out which of my humanities colleagues might be a good person to ask. Surely somebody at Oxford can help me get to the bottom of this?) Update (5/07/13): I have now heard from Alan Hughes from the Oxford English Dictionary. His response was very illuminating: Topologic does occur, but much less frequently than topological: in Google Books, 31k against 2.6m; in the Oxford English Corpus, 8 vs 1400; say three orders of magnitude difference. Geometric and geometrical seem to be the oldest English words to have the endings -metric and -metrical (geometrical is 14th c., geometric is 16th c.). The revised (OED3) entry for -metrical says "Where matching formations in -metric and -metrical exist, there is a tendency for the formation in -metrical to be earlier." Geometric mean occurs from 1701, but we have no OED entry for geometrical mean, supporting Peter's comment below [map: above]. Words in -ology generally > adjectives in -logical; but American English often uses -logic for scientific words, e.g. hematologic instead of haematological, geologic instead of geological. This may account for modern occurrences of topologic (in OED1 the word is attested with quotations of 1872 and 1903, but neither is to do with maths). The ending is later in English formations. OED3 notes at -ology "From the late 18th cent. onwards the element is freely used with first elements of classical origin to form the names of branches of study." Perhaps the lateness of -ology means there is less variability (between -ic and -ical) than is the case with words in -metric(al). There is sometimes a semantic difference between -ic and -ical: a historical novel (about subjects in history) but a historic feat (it will go down in history). The OED3 entry for algebraical (1571-, earlier than algebraic, 1653-) says "Originally: = algebraic adj. 1. In later use chiefly: characteristic or reminiscent of algebra." My view is that you need have no qualms at all about using geometric and topological in the same context, If one departs from what is usual usage, a reader is apt to be distracted by the language away from the meaning intended. So there you have it. A dude from the OED has spoken, and it turns out that my speculation that the difference might pertain to the ending 'ology' has some basis in truth. I hope that you have enjoyed this grammatical excursion into the history of mathematics. Or maybe this has actually been a grammatic excursion. :)
Friday, May 03, 2013
Thursday, May 02, 2013
Wednesday, May 01, 2013
A few minutes ago, I pulled the Facebook version of Fermat in commenting on a status update: "My comment is long and there isn't enough space to put it here." (Technically, I did put a bit of a pointer to where people could find my commentary, but I like the fact that I started with the above line.)
Tommy Lasorda appears to be extremely confused by PSY's shenanigans. This is pretty damn funny, actually. Just don't ask Tommy to give his opinion of PSY's performance. (Tip of the cap to whoever does Facebook posts for Major League Baseball.)
Here is an article about Diederik Stapels and his academic fraud. This case is extreme, but of course --- and sadly --- more subtle frauds are rampant throughout science. The article is long, but in my opinion it is required reading if you're a scientist.