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9:52 AM | Where People Bike and Run, Worldwide

Remember those running maps I made with limited data from RunKeeper? Strava, which also provides an app to track your …

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9:40 AM | Elsevier journals — some facts

A little over two years ago, the Cost of Knowledge boycott of Elsevier journals began. Initially, it seemed to be highly successful, with the number of signatories rapidly reaching 10,000 and including some very high-profile researchers, and Elsevier making a number of concessions, such as dropping support for the Research Works Act and making papers […]

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I realize it's still April. Our last day of school is May 14th. But, I'm already thinking about next year. In fact, I'm thinking a lot about next year. Things I want to do. Things I don't want to do. Things I need to do. Things I should think about doing. Here's the deal. Oklahoma is changing standards next year. Originally, we were a PARCC state. Next year is supposed to be our first year of full implementation of Common Core. […]

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7:55 AM | Navigare con la matematica – Maddmaths!

Navigare con la matematica leggi articolo completo

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7:29 AM | Announcement: TikZ workshop

I should’ve made this announcement sooner, but today I am giving an introductory workshop to TikZ (and friends). It is organised by my friends of PRIME and takes place today (Thursday, April 24) at 17h30 in room Turing, of building S9 on the Sterre campus of Ghent University. Everyone can attend, but it will be […]

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No summary available for this post.

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6:00 AM | 5535

5535 = 3 x 3 x 3 x 5 x 41.Every digit of 5535 is a prime factor of 5535 (A062239).5535 and the square of 5535 use only the digits 0, 2, 3, 5, and 6 (A136888).5535 is a number n such that n3 - 4 and n3 + 4 are prime (A161589).5535 is a number n such that (n3 + 2 and n3 + 4) is a twin prime pair (A178337).5535 divides 7312 - 1.5535 is a number that cannot be written as a sum of three squares.Source: OEIS

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Anche le scimmie sanno la matematica leggi articolo completo

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I’ve been an editor of JSS for the last few years, and as a result I tend to get email from people asking me about publishing papers describing R packages in JSS. So for all those wondering, here are some general comments. JSS prefers to publish papers about packages where the package is on CRAN and has been there long enough to have matured (i.e., obvious bugs ironed out and a few active users). This is partly because we have so many submissions that it helps to filter some out and this […]

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Risorse di matematica dalle scuole elementari fino alle scuole superiori leggi articolo completo

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5:32 AM | NASA Space Crews

In the Apollo missions many of the crew were experienced, but some were
not. So I drew a diagram - see what patterns you see.

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5:32 AM | Software Checklist

During the second World War, fighter pilots would scramble to take off.
Their heart would stop when the engine mis-fired. Was the fuel mix too
rich, or too lean? Turn the control wrong way and they could die ...

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Equazione parametrica di secondo grado vedi video

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5:26 AM | Invariant subspaces and Deddens algebras

My paper entitled `Invariant subspaces and Deddens algebras’ has been accepted for publication in Expositiones Mathematicae. Here is the abstract It is shown that if the Deddens algebra associated with a quasinilpotent operator on a complex Banach space is closed … Sigue leyendo →

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Here is a somewhat 'older' blind deconvolution algorithm (compared to this one)Blind Image Deblurring by Spectral Properties of Convolution Operators by Guangcan Liu, Yi MaIn this paper, we study the problem of recovering a sharp version of a given blurry image when the blur kernel is unknown. Previous methods often introduce an image-independent regularizer (such as Gaussian or sparse priors) on the desired blur kernel. For the first time, this paper shows that the blurry image
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The last of the three examples involving the composition of triadic relatives with dyadic relatives is shown again in Figure 25. (25) The hypergraph picture of the abstract composition is given in Figure 26. (26) This example illustrates the way that Peirce … Continue reading →

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This will be the fifth and final NCTMNOLA Processing Session. It’ll be short too, just a quick debrief. I vacillate between the poles of “math is different” and “math is just like other subjects.” Sometimes I wonder if math teachers … Continue reading →

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Those most mathematical fun I had at NCTMNOLA was in sessions focused on Elementary School level math. Either by accident or by impulse I found myself drifting into sessions that one would associate with K-5. Well, if that’s the case, … Continue reading →

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1:57 AM | The Math of Rock Climbing

What's it like to fall 40 feet down a sheer cliff face, while dangling from a rope hundreds of feet from the ground? Emory mathematician Skip Garibaldi describes his rock climbing experiences on El Capitan in Yosemite National Park. He also explains some basic climbing math, such as the fall factor, used to reduce the risk of injury during a rope climb.

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In between the instant they opened the door to Jo Boaler’s talk on “Promoting Equity Through Teaching for a Growth Mindset” and when she began speaking, I, Eleanor, and a few others in my row banded together as Jo Boaler … Continue reading →

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1:42 AM | ITU 100 GHz Frequency Grid Math

Introduction A physicist in my group and I were having a discussion about how the wavelengths (i.e. colors) for lasers are specified by an international standard and I thought this discussion would provide a nice example of a differential approximation. … Continue reading →

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backwardinduction:
In mathematics, an algebraic set is the set of solutions of a system of polynomial equations. Algebraic sets are sometimes also called algebraic varieties, but normally an algebraic variety is an irreducible algebraic set, i.e. one which is not the union of two other algebraic sets. Algebraic sets and algebraic varieties are the central objects of study in algebraic geometry. The word “variety” is employed in the sense which is similar to that of manifold;
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1:01 AM | Believe it or not, we've been talking about the nice Krugman -- some perspective on the 538 debate

[You may have trouble getting past the NYT firewall on these. If so, the easiest way around this is either to Google name and author or do what I did and go here for a complete set.]One of the side questions in the ongoing 538 debate is whether or not Nate Silver and his writers are being excessively criticized. There is certainly some truth to the charge (for reasons I'll get into later), but it's also important to remember that, to a remarkable extent, Silver walked into a bar fight, a number […]

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11:44 PM | Manitoba Education Minister takes a swipe at Alberta’s “not as successful” math curriclum

Manitoba Education Minister takes a swipe at Alberta’s “not as successful” math curriclum: David Staples:
In response to concerns from parents and experts, such as University of Manitoba math professor Robert Craigen and University of Winnipeg math professor Anna Stokke, the Manitoba brought in a number of chances.
"the Manitoba brought in a number of chances"!?
[source: mme rss]

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11:30 PM | On This Day in Math - April 24

Simplicibus itaque verbis gaudet Mathematica Veritas, cum etiam per se simplex sit Veritatis oratio.(So Mathematical Truth prefers simple wordssince the language of Truth is itself simple.)~ Tycho BraheThe 114th day of the year; the sum of the first 114 digits of e after the decimal point, is prime. This is the third consecutive day number with this property. And From Mario Livio: The number of ways of coloring the faces of a cube with 3 different colors is 114.EVENTS1066 Halley's Comet […]

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Apparently, adults are still telling children who will definitely be going to go to college that they should try to get into the best college possible. Moreover, apparently we teachers are actively encouraging our high-flying students to get into the highest-ranked college possible.Here's my argument that this is an awful thing and that we should stop.You'll learn more at the top-notch universities.Let's start with the observation that universities don't typically do anything interesting, […]

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In a comment to the previous post on the Fermi Paradox, David Wallace wrote this terrific exposition of it. I agree with almost everything he says, so I will save my own quibbles for a comment. David writes: Just to clarify the force of the Fermi paradox (which is intended...

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A large chunk of machine learning (although not all of it) is concerned with predictive modeling, usually in the form of designing an algorithm that takes in some data set and returns an algorithm (or sometimes, a description of an algorithm) for making predictions based on future data. In terminology more friendly to the philosophy […]

Bailey, D., Borwein, J., de Prado, M.L. & Zhu, Q. (2014). Pseudo-Mathematics and Financial Charlatanism: The Effects of Backtest Overfitting on Out-of-Sample Performance, Notices of the American Mathematical Society, 61 (5) 458. DOI: 10.1090/noti1105

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Here the monotonicity of the EM algorithm is established. $$ f_{o}(Y_{o}|\theta)=f_{o,m}(Y_{o},Y_{m}|\theta)/f_{m|o}(Y_{m}|Y_{o},\theta)$$ $$ \log L_{o}(\theta)=\log L_{o,m}(\theta)-\log f_{m|o}(Y_{m}|Y_{o},\theta) \label{eq:loglikelihood} $$ where \( L_{o}(\theta)\) is the likelihood under the observed data and \(L_{o,m}(\theta)\) is the likelihood under the complete data. Taking the expectation of the second line with respect to the conditional distribution of
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Ruslan R Salakhutdinov, Sam T Roweis & Zoubin Ghahramani (2012). On the Convergence of Bound Optimization Algorithms, arXiv, arXiv: 1212.2490v1

Wu C.F.J. (1983). On the Convergence Properties of the EM Algorithm, The Annals of Statistics, 11 (1) 95-103. DOI: 10.1214/aos/1176346060

McLachlan G. & Peel D. DOI: 10.1002/0471721182

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by @ulaulaman about #exoplanets #planetary_transit #kepler_mission #nasa #astronomy The search for extrasolar planets (or exoplanets) had its first success in 1991 with the discovery of some planets orbiting around the pulsar PSR1257+12(1, 2, 3), measuring the variations of the radio pulses coming from the star. The second important milestone in exoplanet research takes place in 1995, with the discovery around the star 51 Pegasi (a star like our Sun) of a Jupiter-like planet, found at a […]

Wolszczan, A. & Frail, D. (1992). A planetary system around the millisecond pulsar PSR1257 + 12, Nature, 355 (6356) 145-147. DOI: 10.1038/355145a0

Wolszczan, A. (1994). Confirmation of Earth-Mass Planets Orbiting the Millisecond Pulsar PSR B1257 + 12, Science, 264 (5158) 538-542. DOI: 10.1126/science.264.5158.538

Mayor, M. & Queloz, D. (1995). A Jupiter-mass companion to a solar-type star, Nature, 378 (6555) 355-359. DOI: 10.1038/378355a0

Borucki, W., Koch, D., Basri, G., Batalha, N., Brown, T., Caldwell, D., Caldwell, J., Christensen-Dalsgaard, J., Cochran, W., DeVore, E. & Dunham, E. (2010). Kepler Planet-Detection Mission: Introduction and First Results, Science, 327 (5968) 977-980. DOI: 10.1126/science.1185402

Lissauer, J., Fabrycky, D., Ford, E., Borucki, W., Fressin, F., Marcy, G., Orosz, J., Rowe, J., Torres, G., Welsh, W. & Batalha, N. (2011). A closely packed system of low-mass, low-density planets transiting Kepler-11, Nature, 470 (7332) 53-58. DOI: 10.1038/nature09760

George, S. (2011). Extrasolar planets in the classroom, Physics Education, 46 (4) 403-406. DOI: 10.1088/0031-9120/46/4/004

LoPresto, M. & McKay, R. (2005). An introductory physics exercise using real extrasolar planet data, Physics Education, 40 (1) 46-50. DOI: 10.1088/0031-9120/40/1/003

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Non voglio fare concorrenza alla splendida spiegazione di Amedeo o a quella tecnica di Corrado, ma mia sorella, leggendo il post di pancia scritto nella sera dell'annuncio di BICEP2, ha candidamente confessato di non aver capito cosa era accaduto quel giorno. E allora proviamoci, a raccontarlo. (da The Cartoon History of the Universe #1 di Larry Gonick)C'era una volta un'idea di universo, che era la Terra al centro, quindi il Sole, la Luna e gli altri pianeti e sullo sfondo le stelle fisse,
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Hubble E. (1929). A relation between distance and radial velocity among extra-galactic nebulae, Proceedings of the National Academy of Sciences, 15 (3) 168-173. DOI: 10.1073/pnas.15.3.168

Gamow G. (1948). The Evolution of the Universe, Nature, 162 (4122) 680-682. DOI: 10.1038/162680a0

Alpher R.A. & Herman R. (1948). Evolution of the Universe, Nature, 162 (4124) 774-775. DOI: 10.1038/162774b0

Alpher R., Bethe H. & Gamow G. (1948). The Origin of Chemical Elements, Physical Review, 73 (7) 803-804. DOI: 10.1103/PhysRev.73.803

Peebles P.J.E., Schramm D.N., Turner E.L. & Kron R.G. (1994). The Evolution of the Universe, Scientific American, 271 (4) 52-57. DOI: 10.1038/scientificamerican1094-52

McLeish T.C.B., Bower R.G., Tanner B.K., Smithson H.E., Panti C., Lewis N. & Gasper G.E.M. (2014). History: A medieval multiverse, Nature, 507 (7491) 161-163. DOI: 10.1038/507161a

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Much of my undergrad was spent studying physics, and although I still think that a physics background is great for a theorists in any field, there are some downsides. For example, I used to make jokes like: “soft isn’t the opposite of hard sciences, easy is.” Thankfully, over the years I have started to slowly […]

Lazer, D., Kennedy, R., King, G. & Vespignani, A. (2014). Big data. The parable of Google Flu: traps in big data analysis., Science, 343 (6176) 1203-1205. PMID: 24626916

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mathhombre tweeted: @mathhombre

RT @tchmathculture: Math Deparments that Support All Students’ Learning http://t.co/ng4XNAsybl

2014-04-24 18:05:59

mathhombre tweeted: @mathhombre

RT @doingmath: "Knowing Alongside" http://t.co/yKJcfbpUuq

2014-04-24 18:04:51

j_lanier tweeted: @j_lanier

2014-04-24 18:03:43

MathDisk tweeted: @MathDisk

How Triangles Revolutionized Mapmaking [http://t.co/0LfPMIYQaO] #math

2014-04-24 18:03:30

MindAfterMath tweeted: @MindAfterMath

2014-04-24 18:01:47

MathProjects tweeted: @MathProjects

The universe speaks to us in the language of mathematics, and desperately wants us to know what it has to say.

2014-04-24 17:54:35

gaussianos tweeted: @gaussianos

RT @eliatron: @mtpibtor desde @CCCientifica y @PIkasle, ganadores, ex aequo, del Premio #CarnaMat52 http://t.co/OUwFnOfBdM

2014-04-24 17:46:14

gaussianos tweeted: @gaussianos

RT @juanripu: Clara con limón en Imaginary Logroño @cjgestal @RealSocMatEsp #MathLife http://t.co/w4fAjdrrs9

2014-04-24 17:45:47

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