Posts

April 05, 2015

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5:11 PM | LOG#168. D-dimensional laws(III).
The question of the origin of mass is one of the more important issues in theoretical physics. The existence (or not) of extra dimensions of space and time will likely affect to the final solution of this unsolved problem. The … Continue reading → Tags:  action, BSM physics, Clifford algebra, Clifford algebraic relations, Dirac algebra, Dirac matrices, effective 4D world, effective field theory, effective mass, Euler-Lagrange equations, extra dimensions, Fourier analysis, […]
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4:00 PM | Philip K. Dick (2) vs. George Carlin (2); Hobbes advances
For yesterday’s semifinal, I was all ready to go with this argument by Zbicyclist in favor of Cervantes: For someone who wasn’t writing in English, he’s credited with a fair number of English catchphrases. Let’s bring the old guy back to life and see what else he’s got. When thou art at Rome, do as […] The post Philip K. Dick (2) vs. George Carlin (2); Hobbes advances appeared first on Statistical Modeling, Causal Inference, and Social Science.
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3:36 PM | March Favorites
Hi, everyone! I thought it would be a good idea to do the March Favorites after all (This Week). So, with no further comment lets start the favorites list: 1. Favorite quote(s): I have 2 quotes this month and they problem represent my feelings this month. The first quote was perfect for the 1st part of […]
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1:41 PM | Fear of Alzheimer
I am scared of that old German gentleman. Forgot his name. Oh, yeah. Alzheimer. I started to lose my brain processing speed a long time ago. By my estimates I am about 100 times slower than I used to be. From time to time someone gives me a puzzle I remember I solved in 30 […]
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1:14 PM | This is why I’m a political scientist and not a psychologist
I can understand how people can hold all sorts of wacked-out political views (after all, in the past, people have supported ideas as crazy as abolitionism, polygamy, monarchy, and the nationalization of the means of production), but certain things in psychology just continue to baffle me, even though I know they’re true. The most recent […] The post This is why I’m a political scientist and not a psychologist appeared first on Statistical Modeling, Causal Inference, and […]
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10:59 AM | La scomparsa di Patò
Misteriosa #scomparsa di #Pasqua a #Vigata Il direttore della banca di Vigata, persona rispettata e apprezzato attore dilettante, subito dopo il Mortorio, rappresentazione della passione di Cristo, scompare misteriosamente. Sia la moglie, disperata, sia lo zio, sottosegretario del ministero dell'interno, premono sui pubblici ufficiali per ottenere una soluzione quanto più veloce delle indagini.Andrea Camilleri, ispirato da un passaggio di A ciascuno il suo di Leonardo Sciascia, si lancia […]
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9:45 AM | Cassini ovals
#HappyEaster from @ulaulaman with #math via commonsA Cassini oval is a quartic plane curve defined as the set (or locus) of points in the plane such that the product of the distances to two fixed points is constant. This may be contrasted to an ellipse, for which the sum of the distances is constant, rather than the product. Cassini ovals are the special case of polynomial lemniscates when the polynomial used has degree 2.Cassini ovals are named after the astronomer Giovanni Domenico Cassini […]
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9:27 AM | LOG#167. D-dimensional laws(II).
Let me begin this article in D=d+1 spacetime. We are going to study quantum gases and their statistics in multidimensional space. Usual notation:     In D=d+1 spacetime, the massless free ideal relativistic gas satisfies, as we will show, certain … Continue reading → Tags:  antiboson, BEC, Bose-Einstein condensate thermodinamical properties, Bose-Einstein condensation, Bose-Einstein distribution, Bose-Einstein statistics, Bose-Einsteins condensate temperature, […]

April 04, 2015

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10:15 PM | back from New York
A greatly enjoyable [if a wee bit tight] visit to Columbia University for my  seminar last Monday! (And a reasonably smooth trip if I forget about the screaming kids on both planes…!) Besides discussing with several faculty on our respective research interests, and explaining our views on replacing Bayes factors and posterior probabilities, views that […]
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6:30 PM | LOG#166. D-dimensional laws(I).
My next thread of nested articles are aimed to explore (shallowly, only) the issue of extra dimensions (of space and time!). Let me begin with the Gauss law for the electric field. The electrical flux in D-dimensional space reads, for … Continue reading → Tags:  Ampere law extra dimensions, Bessel function of 2nd type, Biot-Savart law extra dimensions, calculus, Chern-Simons couplings, Coulom law in extra dimensions, Coulomb law, Coulomb law extra dimensions for massive […]
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5:52 PM | Distribution of sick time
Carl Erickson, the president of a small software company, writes that sick time follows a logarithmic distribution.  His terminology is a bit nonstandard, but here’s what he’s saying.  Take all the people who have worked for his company and list the … Continue reading →
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4:00 PM | The Final Four: Cervantes, Hobbes, Dick, Carlin! Today’s semifinal: Miguel de Cervantes (2) vs. Thomas Hobbes
We’re nearing the end! Yesterday‘s winner was decided based on several Carlin quotes. From Paul, a great line on Muhammad Ali: He said, ‘No, that’s where I draw the line. I’ll beat ‘em up, but I don’t want to kill ‘em.’ And the government said, ‘Well, if you won’t kill people, we won’t let you […] The post The Final Four: Cervantes, Hobbes, Dick, Carlin! Today’s semifinal: Miguel de Cervantes (2) vs. Thomas […]
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3:49 PM | LOG#165. Rogers-Ramanujan identities.
There are some cool identities, very well known to mathematicians and some theoretical physicists or chemists, related with Ramanujan. They are commonly referred as Rogers-Ramanujan identities (Rogers, 1894; Ramanujan 1913,1917 and Rogers and Ramanujan, 1919). They are related to some … Continue reading → Tags:  basic hypergeometric functions, Baxter's solution, calculus, classical hypergeometric functions, hard hexagon model, modular functions, q-analogue, q-analogue of […]
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3:24 PM | Why would anyone want to become a security analyst or portfolio manager?
In today’s Wall Street Journal, Jason Zweig frets about the popularity of index funds: If investors keep turning their money over to machines that have no opinion about which stocks or bonds are better than others, why would anyone want to become a security analyst or portfolio manager? Who will set the prices of investments? […]
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3:19 PM | LOG#164. Theta functions.
Hi, there! We are going to explore more mathematical objects in this post. Today, the objects to study are theta functions. A prototype is the Jacobi theta function: (1)   where and . It satisfies the functional equation (2)   … Continue reading → Tags:  1D heat equation, auxiliary Jacobi theta functions, Dirac comb, Dirichlet conditions, functional equation, generalized theta function, heat equation, Jacobi identities, Jacobi theta function, metaplectic group, […]
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2:14 PM | Stan meetup in NYC on Tuesday
The next Stan meetup in NYC is on Tuesday, 4/7/2015. If you have installation issues, modeling trouble, or just want to pick some of the developers’ brains, show up. Free. Registration required: http://www.meetup.com/Stan-Users-NYC/events/221561385/   P.S. Boston, Stan meetups are coming your way. The post Stan meetup in NYC on Tuesday appeared first on Statistical Modeling, Causal Inference, and Social Science.
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1:33 PM | “Thinking about the possibility of spurious correlation isn’t a matter of liking—it should be pretty much automatic.”
I agree with sociologist David Weakliem when he writes the above sentence. Here’s the full paragraph: Krugman says, “you can, if you like, try to argue that this relationship is spurious, maybe not causal.” Actually, I [Weakliem] liked his original figure, since I agree with Krugman on economic policy. But thinking about the possibility of […] The post “Thinking about the possibility of spurious correlation isn’t a matter of liking—it should be pretty […]
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1:13 PM | Aunt Pythia’s advice
Holy shit people we’ve got an awesome column today. Aunt Pythia shall not disappoint, and when she says that, she really means that you wonderful readers have not disappointed Aunt Pythia – your questions are surprising and rich and thoughtful as always. It brings a sweet lightness to Aunt Pythia’s otherwise heavy, snuffly head. For […]
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12:52 PM | Puzzlebomb – April 2015
Puzzlebomb is a monthly puzzle compendium. Issue 40 of Puzzlebomb, for April 2015, can be found here: Puzzlebomb – Issue 40 – April 2015 The solutions to Issue 40 will be posted at the same time as Issue 41. Previous issues of Puzzlebomb, and their solutions, can be found here.
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12:18 PM | New York skyline
Filed under: Kids, pictures, Travel, University life Tagged: Broadway, Columbia University, New York city, sunset
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8:20 AM | Faccia di Luna
Il mondo di Jodorowsky è popolato di personaggi estremi ed estremizzati che in Faccia di Luna trovano una casa comune. In un mondo distopico, rappresentato da una società chiusa e confinata su un'isola, retto politicamente da una coppia di fratelli-amanti, in realtà fantocci dell'autorità religiosa, fa la sua comparsa Borrado, senza volto e senza parole, che romperà l'equilibrio tra le forze ribelli e quelle governative, che a loro volta finanziano e […]
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6:00 AM | Cancer, bad luck, and a pair of paradoxes
Among the highlights of my recent visit to IMO were several stimulating discussions with Artem Kaznatcheev. I’m still thinking over my response to his recent post about reductionist versus operationalist approaches in math biology, which is very relevant to some of my current research. Meanwhile, at Artem’s suggestion, this post will discuss a reanalysis of the “cancer and […]
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