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Posts

March 29, 2015

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9:26 AM | Affine Transformation
via SeperateIntegrate
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8:43 AM | Stop BIDMAS (PEMDAS)
Skips over a few things but the message is bang on. Such a shame that in almost the same breath the author created a video showcasing how great FOIL is (wrong…wrong…wrong…wrong).
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7:30 AM | Details, Details, Details, ...
March 29th, 2015How long is a year on Neptune?Well a year on Neptune takes 1 […]
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4:40 AM | Paper helicopters at a science fair
Today, we ran Box’s paper helicopter experimental design example at the Science Street Fair  sponsored by the NZ Association of Scientists and hosted by the Museum of Transport and Technology.It went fairly well. In particular, the younger kids really liked dropping paper helicopters and comparing different designs and we got in a few useful discussions of experimental design with adults — mostly school teachers.Things to note:Use a photocopier and pre-printed design template, such as […]
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3:17 AM | Quality of Service (QOS), VOIP, and Netflix
I have a fairly extensive SIP based VOIP system. Recently, after buying a FireTV Stick for Christmas, I've been having lots of complaints about "breaking up" when the kids are streaming high def content, like Sesame Street or nature shows about ants or whatever. I thought this was fairly odd, because I run an OpenWRT […]
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3:14 AM | Your (very own) personalized genomic prediction varies depending on who else was around?
As if I wasn’t skeptical enough about personalized predictions based on genomic signatures, Jeff Leek recently had a surprising post about a “A surprisingly tricky issue when using genomic signatures for personalized medicine“.  Leek (on his blog Simply Statistics) writes: My student Prasad Patil has a really nice paper that just came out in Bioinformatics (preprint in case paywalled). […]
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1:55 AM | The Signal and the Noise
I recently finished Nate Silver‘s famous book. Some parts were more fun to read than others, but overall, it was worth the read. I was impressed by Nate’s apparently vast perspective, and he did a good job of pointing out how bad we are at predicting certain things (and explaining some of the bottlenecks). Based on…
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1:49 AM | Riemann zeta function: correlations between the properties of the local maxima of the Riemann-Siegel Z function and the properties of some fractal features
primepatterns:In my previous post I provided some initial evidence of a remarkable correlation between the number, position and relative size of the major butterflies of the fractal formed from iteration of the Riemann zeta function, and the number, position and relative amplitude of the maxima of the Riemann-Siegel Z function.I promised to provide further evidence for the correlation by showing a map of a region of the fractal at a height of around 2447i where there is a particularly large […]
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1:11 AM | Projective objects
The goal of this post is to summarize some more-or-less standard facts about projective objects. A subtlety that arises here is that in abelian categories there are several conditions equivalent to being projective (we’ll list seven of them below) which are not equivalent in general. We’ll pay more attention than might be usual to this […]
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12:38 AM | Before a break: Seniors Think 'School'
The seniors completed their final presentations this week. This was a series of TED style talks on subjects ranging from 3D printing and product placement to the connections between meat and cancer and the lack of women in foreign policy. … Continue reading →
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12:00 AM | On This Day in Math - March 29
von Mädler Map of Moon, *www.RareMaps.comNatural selection is a mechanism for generating an exceedingly high degree of improbability. ~R. A. FisherThe 88th day of the year; 882 = 7744, it is one of only 5 numbers known whose square has no isolated digits. (Can you find the others?) [Thanks to Danny Whittaker @nemoyatpeace for a correction on this.]88 is also a chance to introduce a new word (new for me).  88 is strobogrammatic, a number that is the same when it is rotated 180o about its […]

March 28, 2015

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11:43 PM | When great man walks among fools, the fools know him not.
This is what my guru looks like. This has got to be one of my favorite humans currently on the planet.  And I've never met him in person.  I aim to remedy that in April. Turns out lemons are sour. Money is not a measure of greatness, heart is...although this guy has made more money in a year than many people reading this will make in their lifetime.  This is a good ol' Montana boy who has done good. If you have a message you want to get out to the world, (mine just so happens to […]
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11:42 PM | Week 14
Welk deel van het vierkant is gekleurd?
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11:15 PM | off to New York
I am off to New York City for two days, giving a seminar at Columbia tomorrow and visiting Andrew Gelman there. My talk will be about testing as mixture estimation, with slides similar to the Nice ones below if slightly upgraded and augmented during the flight to JFK. Looking at the past seminar speakers, I […]
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11:08 PM | On the “clientèle-based” logic in redefining academic units
Are we just a service department? I don’t believe Princeton’s Mathematics department thinks so, neither does any Chemistry department on this continent. Yet, a Vice-President of the Canadian Mathematical Society wants us “to come to the realization that in almost … Continue reading →
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11:03 PM | IL (NON) CARNEVALE DELLA FISICA #7
"Certe volte mi domando perché sia stato proprio io a elaborare la teoria della relatività. La ragione, a parer mio, è che normalmente un adulto non si ferma mai a riflettere sui problemi dello spazio e del tempo. Queste sono cose a cui si pensa da bambini. Io invece cominciai a riflettere sullo spazio e sul tempo solo dopo essere diventato adulto. Con la sola differenza che studiai il problema più a fondo di quanto possa fare un bambino." Albert EinsteinBenvenuti alla 7ª […]
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10:56 PM | CPLEX Performance Variability
It may come as a surprise to some users of CPLEX that its performance is, somewhat intentionally, random. (This may be true of some other optimization software as well. I'll limit the assertion to CPLEX because CPLEX is the only solver for which I have first-hand knowledge that it's true.)A certain amount of uncertainty about performance is probably inevitable. Operating systems swap programs in and out of memory and processes in and out of CPU cores in ways uncontrollable by the CPLEX user, so […]
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9:40 PM | An identity
The following problem is apparently a bonus question for 13 year olds at a local girls school: Evaluate the sum [tex] \displaystyle \frac{1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4} + \cdots + \frac{1}{99} – \frac{1}{100}}{\frac{1}{1+101}+ \frac{1}{2+102} + \cdots + \frac{1}{50+150}}. [/tex] It’s not that easy if … Continue reading →
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9:00 PM | The Rhetoric of Weird Wonders Gleefully Carousing in Morphospace : The Biodiversity Heritage Library’s Flickr Collection
Plate from Anatomie der Echinothuriden – Walter Schurig [1906] The Biodiversity Heritage Library is a consortium of natural history and botanical libraries that cooperate to digitize the legacy literature of biodiversity held in their collections and to make that literature available for open access and responsible use as a part of a global biodiversity commons. […]
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8:53 PM | sheaf cohomology for kindergarteners
sheaf cohomology for kindergarteners
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7:55 PM | Some lectures
Some things spotted recently: an absolutely star-studded conference in Zürich next june Jean-Pierre Serre giving strings of lectures at 88 Peter Scholze lecturing in Ann Arbor at 27 a pretty expensive set of compass and rulers and, finally, last week in the fine small city of Saverne : (Picture in the Public Domain)
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7:42 PM | Helping Students SOAR
I just finished my fourth of twelve classes for my master's in curriculum and instruction with an emphasis in math education.  That means I'm officially 25% done with grad school!  And, yes, I am counting.  :) My last class was focused on teaching problem solving, and I have to say it was the most interesting and useful class I have taken so far.  Today, I want to post one of the homework assignments I did for this class.  Our assignment was to make a poster describing […]
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7:36 PM | Math Mammoth Percent book updated
Math Mammoth Percent is a worktext (with both instruction & exercises) that teaches students the concept of percent, how to calculate the percentage of a number, to figure discounts, sales tax, and interest, to draw circle graphs, to differentiate between a percent of change and a percent of comparison, and to know how to calculate both.The text is suitable for grades 6 through 8 (middle school).This book has been now updated to include many new lessons that will ALSO be in the upcoming […]
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7:32 PM | Links: HBR article on Women in STEM and AAUW Report
A latest article on bias issues for women in STEM by Harvard Business Review.  A slide presentation by AAUW related to their report: Solving the Equation: The Variables for Women’s Success in Engineering and Computing.  The full report can be downloaded for free here.  
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7:21 PM | سلسلة حساب التكامل - س21- Calcul d’intégrale
سلسلة حساب التكامل - س21- Calcul d’intégrale <!-- mathsways336-280 --> (adsbygoogle = window.adsbygoogle || []).push({}); ما يلي شرح شامل لجميع دروس الثانية بكالوريا لكل الشعب العلمية بالاضافة الى سلسلة هائلة من التمارين المحلولة مع الشرح بالفيديو. كما يتم اضافة الجديد اسبوعيا وفي بعض الاحيان […]
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7:20 PM | Week 13
Een muntstukje met een diameter van 2 heeft in het midden een gaatje. Men plaatst een potloodpunt in dit gaatje en rolt het muntstukje langs de buitenrand van een driehoek met omtrek 18. Bij het rollen wordt door het potlood een baan uitgetekend.Bereken exact de lengte van die baan?Oplossing week 13
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7:00 PM | Reutersvard's figure
Variation of Reutersvard's figure by Jep Lor   http://im-possible.info/english/art/computer/jep-lor.html   Author - https://www.behance.net/jeplor
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6:44 PM | Motion under a constant Minkowski force
Reference: Griffiths, David J. (2007), Introduction to Electrodynamics, 3rd Edition; Pearson Education – Chapter 12, Problem 12.60. The Minkowski force is the rate of change of four-momentum with respect to proper time, and allows Newton’s law to be written in its natural form where is the proper acceleration, or second derivative of position with respect […]
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4:43 PM | Tormenta nera
E' notizia recente che Yoshihiro Tatsumi è morto. Come ricordato anche su LSB, Tatsumi è il fondatore del gekiga, il manga serio e adulto rispetto a quello sbarazzino più famoso e diffuso, in sostanza l'equivalente del romanzo a fumetti occidentale.Come visto all'inizio della serie dedicata ad Astro Boy, Osamu Tezuka è considerato come il "Dio del manga" e tra i suoi allievi è presente anche Tatsumi, che però deciderà di portare la lezione del suo maestro verso un approccio più […]
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4:19 PM | Where’s the Function?
This question was another question from the January 2013 C3 paper that I remember almost foxing some of my students of the time: It’s a strange question in that it asks for ff(-3) but, unusually, doesn’t define the function algebraically. I remember the day of the exam three of them discussing the paper with me […]
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