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7:30 AM | Brain-O Quiz Answers

8/31/2015 Answers to Last Fridays Brain-O Quiz: 1. You might fine “begi
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1:06 AM | Oliver Sacks... Story-teller

My inclination, upon hearing of Oliver Sacks' death, was to note it, but not attempt any further tribute, since so many will be penning better pieces than I can (plus, he doesn't fit that easily into a mathematics blog). But on reflection, as a small memorial, I've decided to re-run here at MathTango, the below entry that was originally posted at Math-Frolic over two years ago [...I've also now

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8:54 PM | Statistical Independence – Sunday Puzzle

Two events are statistically independent if the outcome of one does not affect the probability of the other. For instance, if I flip two coins, the fact that one coin shows heads in no way affects the outcome of the other coin. On the other hand, if I deal out cards for game, then the … Continue reading Statistical Independence – Sunday Puzzle

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4:41 PM | New Year Warm Up 2015

For the last few years, at about this time, I've posted a few maths questions by way of a warm up for the encroaching academic year. I see no reason not to continue this short-lived tradition so here are some more. These are all questions I wrote for this year's Charterhouse Foundation Scholarship Exam which is designed for students in Year 8. We wish to identify those who show most mathematical promise for their arrival at the beginning of Year 9 (or the fourth form as it's called here). Very […]

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Some time ago, I have written a post about tiling: Floors of Derelict Buildings with Tile-like Patterns and after that I have been looking for more information about tiling and recently I got to this really interesting article: With Discovery, 3 Scientists Chip Away at an Unsolvable Math Problem. The article tells the story of […]

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1:34 PM | Market Packing

Hexagonal close packing of "spheres" at a market in Tblisi, Georgia.
The displayed produce at the market illustrates a variety of packing strategies, from random to close, depending on the size and shape of the items and other constraints.
Photos by I. Peterson

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This Sunday's reflection from Freeman Dyson (in "Dreams of Earth and Sky"):
"A typical proton-proton collision in the LHC will produce a large spray of secondary particles, and the collisions are occurring at a rate of millions per second. The machine must automatically discard the vast majority of the collisions, so that the small minority that might be scientifically important can be

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11:46 PM | littlelimpstiff14u2:
Wavegrower
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littlelimpstiff14u2:
Wavegrower
Oscillations - Harmony - Unity
I’m Frédéric Vayssouze-Faure, a french guy fascinated by wave phenomenons and the vibrating guitar string harmonics theory,
therefore inspired by periodic motions in general, and by the purest
and smoothest of them in particular : those which
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I’m not an Engineer, but I can definitely relate to this!

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3:09 PM | Triking on Square Wheels

A tricycle with square wheels on a circular track at the National Museum of Mathematics in New York City.
Note the Fibonacci spiral pattern at the track's center.
For more on square wheels, see "Riding on Square Wheels."
Photos by I. Peterson

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7:30 AM | The Monk and the Bridges Problem

8/29/20158,292,015 is a composite, deficient, odd, odious and wasteful number. When written in base 36 it is 4XQ5R. And, it can be expressed as the sum of all of the integers from 3741 to 5529.

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12:00 AM | Telephone Keypad Design

Why are the push buttons on a telephone arranged the way they are?

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8:25 PM | L’autre conjecture de Goldbach

Si je vous disais que j’ai résolu la conjecture de Goldbach et que cela m’a pris en tout et pour tout 5 minutes, vous me croiriez ? Probablement pas. Et pourtant… Vous connaissez sans doute la grande conjecture de Goldbach, … Lire la suite →

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This is the eighth post in my new series that seeks to share the best mathematical content on the web. Enjoy! 1. The man behind modern mathematics: Fibonacci Barron’s has an excellent article about Leonardo of Pisa (aka Fibonacci). What I appreciate most is the article is accurate in its history: “the Fibonacci sequence, which … Continue reading This Week in Math (#8): Fibonacci, Android Passwords, and Tall Buildings

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6:01 PM | Volumes

(Click on the comic if you can't see the full image.) (C)Copyright 2015, C. Burke.Shouldn't Volume 6 be three times as meaty as Volume 2? Assuming some books aren't denser than others, of course. Again, there are times I'm surprised that I haven't done jokes like this one before. Come back often for more funny math and geeky comics.

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4:51 PM | Tide Cycles

A wonderful visualization of tide cycles at the Exploratorium in San Francisco.
Each acrylic slice is a hanging record of tide levels for one day, so you can easily pick out the peak of high tide and the valley of low tide. These peaks and valleys shift from day to day and month to month, as influenced by the moon's gravity (and, to a lesser extent, by the sun's gravity). So the timing of

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2:05 PM | Meet XNSPY – An Effective Mobile Spy App

I have been writing & experimenting about major tech tools like smartphones for some time now. Last few years have been really intrusive for the smartphone manufacturers. With increasing mobile phone usage, I see a lot of new problems emerging for families and businesses. Cyberbullying, ePredating, catfishing, scamming, identity theft, patents-theft are just a few…

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1:30 PM | MathLinks Ahead...

...actually, several this week that are only tangential to math:
1) More on Alex Bellos' new loop pool game:
http://www.bbc.com/news/magazine-34015430
2) Madore mazes, hyperbolic surfaces, and Evelyn Lamb:
http://blogs.scientificamerican.com/roots-of-unity/an-epic-quest-on-an-8-812-holed-donut/
3) A new "Math Teachers At Play" blog carnival is up here:
http://mrseteachesmath.blogspot.com/

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11:30 AM | What Did You Do On Summer Vacation?

Siobhan Roberts probably didn't really get a summer vacation, being busier-than-ever with a book tour, but she reports on the mixture of "research and play" that filled the summers of some others:
http://www.newyorker.com/tech/elements/cogito-ergo-summer-the-beauty-of-summer-science

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7:30 AM | Mr. B's Brain-O Quiz # 22

8/28/2015 Mr. B’s “BRAIN-O” QuizGuaranteed to unclog clogged up
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2:57 AM | Octahedral Moondog

Located in the National Gallery of Art's Sculpture Garden, Tony Smith's Moondog is based on a lattice of tetrahedral and octahedral components (15 stretched octahedra and 10 tetrahedra). As described by George Hart, you can think of the structure as part of a diamond crystal lattice, with the smaller tetrahedral faces (visible as equilateral triangles) representing carbon atoms and the

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curiosamathematica:
The sums of the reciprocals of the binomial coefficients over successive diagonals in Pascal’s triangle converge into beautiful patterns, apart from the first and second diagonal (which lead to the series 1 + 1 + 1 + 1 + … and the harmonic series, respectively).
A proof of the identity can be found on cut-the-knot.org.

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Here are the questions, with answers and explanations, for the New York State Geometry (Common Core) Regents exam, Parts 3 and 4. There were 3 questions in Part 3, each worth 4 credits. There were 2 questions in Part 4, each worth 6 credits. Partial credit may be earned. All work must be shown. In general, a correct answer without any work is worth 1 credit, unless that answer is given as a choice and an explanation is required. Link to Part 1Link to Part 2 Part 3 32. As shown in the diagram
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12:16 PM | Flip a Coin - Fay With Your Math (#4)

This is a the fourth problem I have planned in my FWYM series. So far I've chosen one problem on subtraction, one that focuses on logic, and one that uses combinatorics. This next problem gets into probability by looking at coin flips.Of the first four FWYM problems, I am most interested in seeing students' strategies for […]
The post Flip a Coin - Fay With Your Math (#4) appeared first on Math Fireworks.

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I might have posted this already, but here it is again for George! One of my favourite texts written by a mathematician about mathematics and the way in which it is (but ought not be) taught. https://www.maa.org/external_archive/devlin/LockhartsLament.pdf

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di diffusione della scienza e rivoluzioni cc @aubreymcfato @CristianCantoro Utilizzare i dati sulle citazioni in Wikipedia per misurare la diffusione dell'open accessScrivevo all'inizio del 2011 per i festeggiamenti del wiki-decennale di una rivoluzione irreversibile. E' stato piuttosto interessante leggere il titolo che technology review ha utilizzato per raccontare dell'ultimo degli articoli dedicati all'enciclopedia libera: Why Wikipedia + Open Access = Revolution.L'idea degli autori, Misha
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Nielsen, F. (2007). Scientific citations in Wikipedia, First Monday, 12 (8) DOI: 10.5210/fm.v12i8.1997

Heather Ford, Shilad Sen, David R. Musicant & Nathaniel Miller (2013). Getting to the source: where does Wikipedia get its information from?, Proceedings of the 9th International Symposium on Open Collaboration, DOI: 10.1145/2491055.2491064

Misha Teplitskiy, Grace Lu & Eamon Duede (2015). Amplifying the Impact of Open Access: Wikipedia and the Diffusion of Science, Wikipedia Workshop at 9th International Conference on Web and Social Media (ICWSM), arXiv: 1506.07608v1

Citation

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After (or before?) @StartsWithABang's balloon animals' post? A couple of week ago Ethan Siegel published a post about ballon animals, so I decide to repost an old piece that I wrote in 2011 for my italian blog: the english version is lost, but it is magically reposted here! Two one-balloon constructions and their associated graphsI recently discovered this interesting site, vihart. In the site there are some interesting paper and today I want to write something about Computational Balloon
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Demaine E.D., Demaine M.L. & Hart V. (2008). Computational balloon twisting: The theory of balloon polyhedra., Proceedings of the 20th Canadian Conference on Computational Geometry (CCCG2008), 139-142.

Bryś K. & Lonc Z. (2009). Polynomial cases of graph decomposition: A complete solution of Holyer's problem, Discrete Mathematics, 309 (6) 1294-1326. DOI: 10.1016/j.disc.2008.01.054

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Supponiamo di doverci confrontare con un animale, ad esempio un cane o un lupo (o più in generale con un animale, addomesticato o selvaggio). Secondo Konrad Lorenz il comportamento aggressivo di un cane viene influenzato da due stati d'animo differenti: l'ira e la paura.Si può allora provare a prevedere il comportamento del cane in funzione di quale dei due stati domina: nel caso in cui l'animale è dominato da paura o da ira, proporre una previsione è abbastanza semplice; nel caso in cui il […]

Zeeman E.C. (1976). Catastrophe Theory, Scientific American, 234 65-83. DOI: 10.1038/scientificamerican0476-65

Jean Petitot (2013). Complexity and self-organization in Turing, The Legacy of A.M. Turing, (E. Agazzi, ed.), Franco Angeli, Milano, 149-182. arXiv: 1502.05328v1

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Non prevedevo di scrivere la versione italiana di un post sull'ultima news proveniente dal RHIC, ma mi è stato gentilmente chiesto, e provvedo ben volentieri. Inizio, però, con un piccolo cappello, alla fine del quale saprete che c'è anche un piccolissimo pezzetto (il doppio diminutivo è perché i firmatari del papero su arXiv sono veramente tanti) d'Italia in questa interessante scoperta.Tutto nasce da un post, nel flusso twittero, di Annalisa Arci, in cui racconta, in maniera e con un […]

Belavina A.A., Polyakova A.M., Schwartza A.S. & Tyupkina Y.S. (1975). Pseudoparticle solutions of the Yang-Mills equations, Physics Letters B, 59 (1) 85-87. DOI: 10.1016/0370-2693(75)90163-X

Hooft G.'. (1976). Symmetry Breaking through Bell-Jackiw Anomalies, Physical Review Letters, 37 (8) DOI: 10.1103/PhysRevLett.37.8

Hooft G.'. (1976). Computation of the quantum effects due to a four-dimensional pseudoparticle, Physical Review D, 14 DOI: 10.1103/PhysRevD.14.3432

Fukushima K., Kharzeev D.E. & Warringa H.J. (2008). The Chiral Magnetic Effect, Physics Review D, 78 (7) DOI: 10.1103/PhysRevD.78.074033

Kharzeev D.E. & Yee H.U. (2011). Chiral Magnetic Wave, Physical Review D, 83 DOI: 10.1103/PhysRevD.83.085007

STAR Collaboration (2015). Observation of charge asymmetry dependence of pion elliptic flow and the possible chiral magnetic wave in heavy-ion collisions, arXiv, arXiv: 1504.02175v2

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A new clue about the #quarkgluonplasma from @RHIC_STAR at @BrookhavenLabWithin the particles that constitute atomic nuclei, protons and neutrons, there are the quarks, the elementary particles with fractional charges, linked to each other thanks to the gluons, bosons that carry the nuclear interaction. Thanks to the gluons it is impossible to observe, at present, free quarks, but it is expected that in the very first stage of the universe, matter was in a state called quark-gluon plasma. Thanks […]

Belavina A.A., Polyakova A.M., Schwartza A.S. & Tyupkina Y.S. (1975). Pseudoparticle solutions of the Yang-Mills equations, Physics Letters B, 59 (1) 85-87. DOI: 10.1016/0370-2693(75)90163-X

Hooft G.'. (1976). Symmetry Breaking through Bell-Jackiw Anomalies, Physical Review Letters, 37 (8) DOI: 10.1103/PhysRevLett.37.8

Hooft G.'. (1976). Computation of the quantum effects due to a four-dimensional pseudoparticle, Physical Review D, 14 DOI: 10.1103/PhysRevD.14.3432

Fukushima K., Kharzeev D.E. & Warringa H.J. (2008). The Chiral Magnetic Effect, Physics Review D, 78 (7) DOI: 10.1103/PhysRevD.78.074033

Kharzeev D.E. & Yee H.U. (2011). Chiral Magnetic Wave, Physical Review D, 83 DOI: 10.1103/PhysRevD.83.085007

STAR Collaboration (2015). Observation of charge asymmetry dependence of pion elliptic flow and the possible chiral magnetic wave in heavy-ion collisions, arXiv: 1504.02175v2

Citation

MindAfterMath tweeted: @MindAfterMath

Approximating the Set Cover Problem http://t.co/E8SCIiZcMP #compsci #datascience #math #stem #mathchat

2015-08-31 16:45:53

fawnpnguyen tweeted: @fawnpnguyen

@professorpatton Hi Hunter. I did Gone Fishing with mine on 1st day: http://t.co/aboRybZKcf

2015-08-31 16:43:16

OraclMachine tweeted: @OraclMachine

#我的墓志铭 我有突然想到一句不错的，虽然有几分幽怨，但一下就拉近了和扫墓人的距离。可以在我墓碑上写“为什么没有人欣赏我的才华？”

2015-08-31 16:42:58

NISSSAMSI tweeted: @NISSSAMSI

The NISS &SAMSI Mathematics Daily is out! http://t.co/0XEXGH12aF Stories via @ElsevierMath @dansmath @BartStuck

2015-08-31 16:38:05

jamesgrime tweeted: @jamesgrime

Gremlins 2 is better than Gremlins. There, I've said it: Key & Peele - "Gremlins 2" Brainstorm https://t.co/GejVe3YXcf

2015-08-31 16:37:33

mluebbecke tweeted: @mluebbecke

2015-08-31 16:34:35

MindAfterMath tweeted: @MindAfterMath

RT @samim: A Implementation of the Neural Algorithm of Artistic Style : http://t.co/jDhVwt2AXT #GitXiv http://t.co/ja0vhiIuzl

2015-08-31 16:28:59

michiexile tweeted: @michiexile

RT @theengrprof: The horrified face on students' faces when they find out that during "syllabus week", which they skipped, you already cove…

2015-08-31 16:27:07

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