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# Posts

### November 27, 2014

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Hawk moths and impossible geometry   by Gebefreniya   http://im-possible.info/english/art/pencil/gebefreniya.html   Author - http://gebefreniya.deviantart.com/
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Thanksgiving means many things...Turkey and trimmings...the Macy's parade...Detroit Lions football...and, at least in my house...     I have documented the importance of Practice Standard 6, Attend to Precision, in a previous post.  In that case, the failure to demonstrate proficiency led to disastrous consequences.  Here, it's a different story.    Early on in the movie, Santa comes to Toyland to check on his Christmas orders.  The […]
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References: Griffiths, David J. (2007), Introduction to Electrodynamics, 3rd Edition; Pearson Education – Problem 10.18. Here’s a simple example of calculating the fields due to a moving point charge. Suppose we have a charge constrained to move on the axis in the direction, so that . The fields are where and is the particle’s position […]
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Sheets of single-atom thick carbon absorb the impact of bullets more efficiently than steel, paving the way for lightweight, super-strong bulletproof vests
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오랜만에 카메라와 렌즈를 꾸역꾸역 들고 우리 마을 뒷산인 낙산공원을 탐방하고 왔다. 나름 여기 주민인데 한 번 탐방해 줘야지..! 이번에는 혜화동 로터리와 한성대입구역 사이로 성곽길이 존재하길래 그 쪽으로 진입해 보았다. 아래는 구체적으로 이동한 경로: 성곽길을 따라 걷는데 오른쪽의 성곽보다는 왼쪽으로 보이는 … Continue reading →Related Posts ?[학교생활] […]
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Physicist: As long as the person who cut the straws: 1) takes the last remaining straw and 2) has a decent poker face (or doesn’t know which is which), then it’s completely fair.  If they have a bad poker face, … Continue reading →
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References: Griffiths, David J. (2007), Introduction to Electrodynamics, 3rd Edition; Pearson Education – Problems 10.17. We can use the Liénard-Wiechert potentials for a moving point charge to calculate the fields produced by the charge. The potentials are where is the position of the particle at the retarded time and is the velocity at the same […]
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non sempre le cose sono come sembrano. Prendiamo l'esempio del liceo classico....statistica, bias, correlazione, Piero AngelaThe post Cause, effetti e bias appeared first on Il Post.
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In honor of Thanksgiving: take a look at Niall MacKay’s paper Of bombs and boats and mice and men: a random tour through some scaling laws. I mention this because one of the scaling laws there is the time it … Continue reading →
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Nachdem wir die SAMS Bücher durchgelesen haben, versuche ich Carolina für Enid Blyton zu begeistern. Was habe ich ihre Bücher als Kind verschlungen. Fünf Freunde. Geheimnis um. Rätsel um. Die Schwarze Sieben. Sogar Hanni und Nanni habe ich gelesen.Und immer ging es um kluge Kinder, die Verbrechen lösen und Geheimnissen … Continue reading →
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For this conjecture there was found a counter-example, see this online article. The counter-example states that for funcoid . This way I discovered a new function defined by the formula . While and have many cryptomorphisms (that is different but equivalent definitions) and lots of useful usages, all is known about is its definition and […]
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By now, most of us know that girls have great math skills. Still, there are some folks out there who are holding on to the bias that boys naturally have better math abilities than girls. In my latest Math Manifesto video, I go through some of the recent research on gender and math. It’s good news […]
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Mark Palko linked to this data-rich cartoon by Randall Munroe: And I was stunned, first by the data on interracial marriage and then, retrospectively, by my earlier ignorance of these data. Was approval of interracial marriage only 4% in 1958? I had no idea. I looked it up at the Gallup site and it seems […] The post Quantitative literacy is tough! Or, I had no idea that, in 1958, 96% of Americans disapproved of interracial marriage! appeared first on Statistical Modeling, Causal […]
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I like thinking about assessment.  It certainly isn't straight forward, but I find it interesting.  In fact, I find it so interesting and important that I have been pursuing graduate studies on this topic.  Dylan Wiliam (2013) has suggested that assessment is the "central process in effective instruction...[and] the bridge between teaching and learning" (p.15), and I agree with this sentiment.  Usually even the people who strongly disagree with this statement, begin to agree […]
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Imaginary Erdős Number enjoy!
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I just gave a lecture on examples of spectral sequences in algebra and algebraic geometry for the ANAGRAMS seminar and without further ado, here are the notes. Nothing new or insightful in there, just some facts and examples taken together to help me during the lecture.
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[Feature photo (above) by alicepopkorn via Flickr (CC BY 2.0).] Therefore, as God’s chosen people, holy and dearly loved, clothe yourselves with compassion, kindness, humility, gentleness and patience. Bear with each other and forgive whatever grievances you may have against … Continue reading →
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There are two services offered by any publisher: to help you learn what others have written to help you show to others what you have written. These are the two sides of the publishing business. A long time ago, the main reason for the existence of publishers was to spread knowledge, i.e. to offer the … Continue reading The clients of publishers. Before: readers. Now: authors. →
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Happy Thanksgiving!  I know I have so much to be thankful for this year.  One thing I'm thankful for is that not a day goes by where my students don't make me laugh.  So, I think it's only fitting to share some things teenagers say today.  :) Previous Volumes:Volume 1 | Volume 2 | Volume 3 | Volume 4 | Volume 5  Volume 6 | Volume 7 | Volume 8 | Volume 9 | Volume 10Volume […]
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While cleaning up after a successful group build, a colleague and some students had fun making a little Thanksgiving tribute in Zometool.
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There are been three recent pieces about mathematical proof that have caught my attention in the last couple of months: (1) Most recently Keith Devlin’s piece here: (2) Evelyn Lamb’s coverage of Leslie Lamport’s talk at the Heidelberg Laureate Forum (including, importantly, a link to a paper in which Lamport takes a critical look at…
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The title is homage to the Gödel’s Last Letter and P=NP blog, which a week ago had a post entitled Two versus three. At the problem session at the Banff meeting last night, Dugald Macpherson and Andras Pongracz posed various … Continue reading →
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A retraction has appeared for Jens Förster, the former University of Amsterdam social psychologist whose work has come under serious scrutiny by two official committees. Here’s the notice for 2012’s “Sense Creative! The Impact of Global and Local Vision, Hearing, Touching, Tasting and Smelling on Creative and Analytic Thought,” a paper which first appeared in […]
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1 * 1 = 2 * 7 / 14 1 * 1 / 2 = 7 / 14 Also: 11 - 2 - 7 = 1 * √4 Also: 11 = 2 + 7 + (1 * √4)
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Ecco il nuovo rompicapo della settimana, dedicato agli amanti delle carte da gioco.  Nel mazzo di carte che ho in mano mancano alcune carte.Se le distribuisco in numero uguale tra 9 persone, mi avanzano 2 carte.Se le distribuisco in numero uguale tra 4 persone, mi avanzano 3 carte.Se le distribuisco in numero uguale tra 7 persone, me ne avanzano 5.In origine, il mazzo era di 52 carte. Quante carte mancano ora?
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There has been lots of advice lately on how to have a civil conversation at Thanksgiving – NPR ran a piece yesterday on “topics both Democrats and Republicans enjoy”, for example, which made me slightly annoyed and amused – perhaps because I am neither – and inspired this somewhat alternative list of ways to enjoy […]
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Here we look at some of the math behind the cross wind landing applet in the section on adding 2D vectors. The post Math in cross-wind landing vectors applet appeared first on squareCircleZ. Related posts: How to code JSXGraph axes, ticks and grids Trying to code JSXGraph so the axes and grid... Updated Graphs of tan, cot, sec and csc The updated applets on the Graphs of tan, cot,... New Riemann Sums applet Here's some background on the new Riemann Sums applet...
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Una poesia quadrata è una particolare composizione in cui il numero delle sillabe (o di parole) per ogni verso è uguale al numero dei versi, per cui la sua struttura risulta essere una griglia quadrata, come in questo esempio che traggo dalla matematica e poetessa americana JoAnne Growney e che ho adattato alla nostra lingua:When lovers leave, avoid laments. Grab a cactus-- new pain forgets.Se ti lascia,via la pena:sfrega cactuscon la schiena.La poesia quadrata più semplice (1 […]
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Time in the pub led to the realisation that beer spills less easily than coffee, and time in the lab helped explain why
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Proponer un problema atractivo puede traer consigo consecuencias muy interesantes, como la satisfacción por la propia resolución del mismo o el posterior estudio de sus posibles, y siempre enriquecedoras, generalizaciones. Esto es lo que ocurrió en la siguiente historia, protagonizada por Esther Klein, pero en este caso el problema propuesto cambió tanto su vida (principalmente […]Entra en Gaussianos si quieres hacer algún comentario sobre este artículo, consultar […]