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8:09 PM | Size of each object in R's workspace

I’ve googled How do I find out how big my workspace is too many times … here’s the explicit code to run and hopefully the next googler sees this post:
for (thing in ls()) { message(thing); print(object.size(get(thing)), units='auto') }
Fin. You can stop there.
Or for a bit of context… Here’s an example code to generate objects of variable sizes where you might not be sure how big they are:
require(boot)
require(datasets)
data(sunspot.year)
system.time(boot.1
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A Chinese edition of Diebold-Rudebusch, Yield Curve Modeling and Forecasting: The Dynamic Nelson-Siegel Approach, just arrived. (I'm traveling -- actually at IMF talking about Diebold-Rudebusch among other things -- but Glenn informed me that he received it in San Francisco.) I'm not certain that I even knew it was in the works. Anyway, totally cool. I love the "DNS" ("Dynamic Nelson-Siegel") in the Chinese subtitle. Evidently some things just don't translate. Not sure how/where to buy it;
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What is Graham’s Number? (feat Ron Graham)
Graham’s number explained by none other than the man who first imagined this unimaginably big number, Ron Graham. Make sure to also watch the companion video How Big is Graham’s Number?

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Here’s a confession of mine: I’ve never really thought of myself as ‘good at math.’ Yep, I’m a high school math teacher proclaiming my discontent with my mathematical abilities. Ironic? Sad? Make you want to hide your children? Read on, it’s not as bad as you think. Being a math teacher was a second career for […]

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The chances of a presumed “fibroid” being cancerous had long been considered extremely remote. But in recent years, a growing number of doctors have suggested in studies and formal academic discussions that the medical community was using the wrong denominator to assess risk.

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7:17 PM | Rebecca Talks Logic With Her Kids!

I asked you to talk logic with your kids, and Rebecca came through in a big way! What follows is the transcript from her conversation with her kids. I've got some follow-up questions -- see them at the bottom of the post.---Three questions were posed, and I presented them to my children in order. My kids are K (8th grade girl), M (5th grade girl), and J (2nd grade boy).1. Ask your kid: Merds laugh when they're happy. Animals that laugh don't like mushrooms. Do merds like mushrooms? Why?J: Of
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As food companies look to cash in on the decline of cereal sales, expect protein-rich foods to headline their fare.

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I was recently reviewing workshop materials from a transformational geometry session and was directed to the Georgia Deparment of Education website for a unit called Algebraic transformations. This is the fifth unit in their first year (9th grade) course titled Coordinate Algebra. I found the activity/assessment below on page 109 (answer key on page 103). The task was to draw some shapes on a coordinate grid, and transform them using 8 different coordinate rules. Below
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Sarà l'attore Benedict Cumberbatch a interpretare il matematico inglese che aiutò a sconfiggere i nazisti traducendo (anzi hackerando) il sistema di codifica enigma. Il film uscirà nelle sale nel novembre 2014.Chi morì mangiando una mela avvelenata? Biancaneve, qualcuno penserà.Ma non è corretto! Infatti Biancaneve non morì affatto, ma cadde in catalessi fino al suo risveglio.Chi invece non si svegliò più ingerendo una mela"condita" con cianuro di potassio fu uno dei più grandi geni
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5:56 PM | A Better Definition Of “Personalization”

David Wiley: For me, personalization comes down to being interesting. You have successfully personalized learning when a learner finds it genuinely interesting. Providing me with an adaptive, customized pathway through educational materials that bore me out of my mind is not personalized learning. It may be better than forcing me through the same pathway that […]

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Label and number the axis on the graph, how many unique Imaginary Numbers does the graph represent? List them. Filed under: Number Sense, Open Middle

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5:32 PM | Driehoeken en lijnen

voorkennisgoniometrische verhoudingenvectorenvectoren en hoekenvergelijkingen van lijnenrichtingscoëfficiënt en normaalvectorHoofdstuk 2 wiskunde D VWO 4... olé...

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Managing Risk: How to Make Better Decisions | Big Think Edge | Big Think: Big Think Editors:
In the latest installment of Big Think Edge, psychologist Gerd Gigerenzer explains how to analyze risk. The author of Risk Savvy: How to Make Good Decisions, Gigerenzer teaches this exclusive workshop, where he stresses understanding the critical difference between calculable risk and uncertainty.
[source: mme rss]

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5:05 PM | TMC #14 GWWG – Annotated References: the research on explicit teaching of exploratory talk

OK, last summarizing post before I have to get packing.Here is the background research on ‘exploratory talk. Once again, please note that this is NOT required reading! Recreational reading only! So please don't freak out! :)I wanted to provide links and titles to valuable materials.These are listed in order of relevance to the Group Work Working Group morning session — they are not in formal bibliographical form.Shell Centre, MAP PD: Students Working Collaboratively (PD
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References: Griffiths, David J. (2005), Introduction to Quantum Mechanics, 2nd Edition; Pearson Education – Problem 8.12. We’ve seen that if we apply the WKB approximation to a potential well and require that the WKB wave functions match up in the region between the turning points, we get the condition where is the left turning point, […]

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from Thane Rosembaum, professor of law at NYU, here. He argues that Gaza civilians aren't really innocent civilians because they elected Hamas. Isn't this the same argument that Osama bin Laden made for the legitimacy of 9/11? Rosembaum goes on to say: " children whose parents are not card-carrying Hamas...

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4:44 PM | PageRank beyond the Web

I just completed a survey article about uses of PageRank outside of web-ranking. The paper has been submitted to a journal, and I also posted the manuscript to arXiv. David F. Gleich. PageRank beyond the Web. arXiv. cs.SI:1407.5107, 2014. The … Continue reading →

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Much like the presentation by Lei Tang (Wallmart Labs) on Adaptive User Segmentation for Recommendation at last year's GraphLab 2013 (see Slides (pdf) here and video here). Xavier Amatriain, of Netflix, made a presentation of what we should be expecting in terms of recommendation. The idea here is that most of this work cannot be static otherwise your customers just won't be responsive to it. Here are his slides and the attendant videos from the Machine Learning Summer School organized in
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4:06 PM | Rigor + Relevance beyond Caltech

I’ve been busy traveling for most of the last month, and so missed my chance for timely postings about a couple of exciting happenings that highlight how theory can impact practice. But, here are two that I can’t resist a quick post about, even if it is a bit late. First, this year’s ACM SIGCOMM […]

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Photography by Tracy Howl and Paul Clarke Has our newfound massive availability of data improved decisions and lead to better democracy around the world? Most would say, “It’s highly questionable.” Conrad Wolfram’s TEDx UK Parliament talk poses this question and explains how computation can be key to the answer, bridging the divide between availability and [...]

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Photography by Tracy Howl and Paul Clarke Has our newfound massive availability of data improved decisions and lead to better democracy around the world? Most would say, “It’s highly questionable.” Conrad Wolfram’s TEDx UK Parliament talk poses this question and explains how computation can be key to the answer, bridging the divide between availability and [...]

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3:42 PM | The Burden of Large Enrollments

This week I'm at the CRA Snowbird conference, the biennial meeting of CS chairs and other leaders in the field. In 2012 many of the discussion focused on MOOCS. This year the challenge facing most CS chairs are booming enrollments in CS courses. A nice problem to have, but a problem nevertheless.
Last night we had a broad discussion about the burgeoning number of students. Ed Lazowska showed his NCWIT slides giving anecdotal evidence. It's too early to get a complete survey of CS […]

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After typing up 96 citations, researchers from the National Institute for Digestive Diseases, I.R.C.C.S. “S. de Bellis,” in Bari, Italy, apparently ran out of steam for the last five, earning themselves a retraction for plagiarism in a literature review of the effects of probiotics on intestinal cancer. Here’s the notice for “Intestinal Microbiota, Probiotics and […]

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3:21 PM | Math and Twitter

What can a math teacher find out about math from Twitter? I loved this Deb Costello post. I used to do the same thing before google shuttered real-time search. I loved pulling up “math” at the beginning of my classes to see all the post/updates that rolled in. It was always good for a laugh. [...]

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3:14 PM | Sabbatical – one rule

But one decision, one rule, I kept. Almost. I decided not to go into my school. When my sabbatical was approved, May of 2013, I had to make some decisions about the school year that just passed. I chose an institution to take courses, and then I changed, and then I partially changed again. And […]

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3:03 PM | Thoughts on Calculus

All summer it's been looming. Last week it was finally time to do something about it. I attended a training for new/newish AP teachers. And now, a collection of ideas that have resulted.AP CommunityOur instructor for the week knew what she was doing. A teacher of Calculus AB and BC for many years, and with a history of establishing successful AP programs from nothing. A task similar to what I have.The most beneficial aspect was the fact that our instructor has been an exam reader for a number
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2:43 PM | Gods, phylosophy and computers

by @ulaulaman http://t.co/Q3AODpvKAs #Godel #ontologicalproof #god #computer The ontological arguments for the existence of God was introduced for the first time by St. Anselm in 1078: God, by definition, is that for which no greater can be conceived. God exists in the understanding. If God exists in the understanding, we could imagine Him to be greater by existing in reality. Therefore, God must exist.There are a lot of phylosophies, mathematics and logicians that proposed their ontological […]

Christoph Benzmüller & Bruno Woltzenlogel Paleo (2013). Formalization, Mechanization and Automation of Gödel's Proof of God's Existence, arXiv: 1308.4526v4

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Millennials get flack for postponing marriage, living with parents and shying away from homeownership. But maybe they're just responding rationally to their local housing markets.

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This is the 6th (continuing from part I and part II and part III and part IV and part V) in a series of expository posts where we put together in one place the pieces from various places about: how is treated lambda calculus in chemlambda how it works, with special emphasis on the […]

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Last week, I posted about the video shown below, a method that allows you to create infinite chocolate. Watch again the video and observe closely where the extra chocolate came from. After watching this video, watch the following video which discusses the secret behind the trick. You can explore the GeoGebra applet shown in the […]
Math and Multimedia - School math, multimedia, and technology tutorials.

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by @ulaulaman http://t.co/Q3AODpvKAs #Godel #ontologicalproof #god #computer The ontological arguments for the existence of God was introduced for the first time by St. Anselm in 1078: God, by definition, is that for which no greater can be conceived. God exists in the understanding. If God exists in the understanding, we could imagine Him to be greater by existing in reality. Therefore, God must exist.There are a lot of phylosophies, mathematics and logicians that proposed their ontological […]

Christoph Benzmüller & Bruno Woltzenlogel Paleo (2013). Formalization, Mechanization and Automation of Gödel's Proof of God's Existence, arXiv: 1308.4526v4

Citation

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\[(n+1)^3 - n^3 \equiv 1 \mod 6\] Claudi Alsina,, Roger Nelsen,, & Hasan Unal (2014). Proof Without Words: The Difference of Consecutive Integer Cubes Is Congruent to 1 Modulo 6 The College Mathematics Journal, 45 (2), 135-135 DOI: 10.4169/college.math.j.45.2.135 (facebook)

Claudi Alsina,, Roger Nelsen, & Hasan Unal (2014). Proof Without Words: The Difference of Consecutive Integer Cubes Is Congruent to 1 Modulo 6, The College Mathematics Journal, 45 (2) 135-135. DOI: 10.4169/college.math.j.45.2.135

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\[(n+1)^3 - n^3 \equiv 1 \mod 6\] Claudi Alsina,, Roger Nelsen,, & Hasan Unal (2014). Proof Without Words: The Difference of Consecutive Integer Cubes Is Congruent to 1 Modulo 6 The College Mathematics Journal, 45 (2), 135-135 DOI: 10.4169/college.math.j.45.2.135 (facebook)...
Claudi Alsina,, Roger Nelsen,, & Hasan Unal. (2014) Proof Without Words: The Difference of Consecutive Integer Cubes Is Congruent to 1 Modulo 6. The College Mathematics Journal, 45(2), 135-135.
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Claudi Alsina,, Roger Nelsen, & Hasan Unal (2014). Proof Without Words: The Difference of Consecutive Integer Cubes Is Congruent to 1 Modulo 6, The College Mathematics Journal, 45 (2) 135-135. DOI: 10.4169/college.math.j.45.2.135

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La settimana scorsa, su twitter, ho diffuso alcune immagini, foto scattate dalle pagine dal volume Letture da Le Scienze: Fisica delle particelle (un indice del volume), che raccoglieva alcuni articoli usciti sulla rivista italiana (e quindi anche su Scientific American). Poiché ognuna di quelle immagini fa inevitabilmente parte della storia della fisica, mi sembra sensato proporle raccolte insieme in un unico post molto più semplicemente raggiungibile di tanti piccoli... cinguettii.
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Weisskopf, V. (1968). The Three Spectroscopies, Scientific American, 218 (5) 15-29. DOI: 10.1038/scientificamerican0568-15

Barish, B. (1973). Experiments with Neutrino Beams, Scientific American, 229 (2) 30-38. DOI: 10.1038/scientificamerican0873-30

Treiman, S. (1959). The Weak Interactions, Scientific American, 200 (3) 72-84. DOI: 10.1038/scientificamerican0359-72

Cline D.B., Mann A.K. & Rubbia C. (1974). The Detection of Neutral Weak Currents, Scientific American, 231 (6) 108-119. DOI: 10.1038/scientificamerican1274-108

Glashow, S. (1975). Quarks with Color and Flavor, Scientific American, 233 (4) 38-50. DOI: 10.1038/scientificamerican1075-38

Nambu, Y. (1976). The Confinement of Quarks, Scientific American, 235 (5) 48-61. DOI: 10.1038/scientificamerican1176-48

Johnson, K. (1979). The Bag Model of Quark Confinement, Scientific American, 241 (1) 112-121. DOI: 10.1038/scientificamerican0779-112

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#sand #battery #chemistry #energy This is the holy grail – a low cost, non-toxic, environmentally friendly way to produce high performance lithium ion battery anodesZachary FavorsSchematic of the heat scavenger-assisted Mg reduction process.Herein, porous nano-silicon has been synthesized via a highly scalable heat scavenger-assisted magnesiothermic reduction of beach sand. This environmentally benign, highly abundant, and low cost SiO2 source allows for production of nano-silicon at the
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Favors, Z., Wang, W., Bay, H., Mutlu, Z., Ahmed, K., Liu, C., Ozkan, M. & Ozkan, C. (2014). Scalable Synthesis of Nano-Silicon from Beach Sand for Long Cycle Life Li-ion Batteries, Scientific Reports, 4 DOI: 10.1038/srep05623

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MindAfterMath tweeted: @MindAfterMath

Hidden Markov Models: The Baum-Welch Algorithm http://t.co/HBn6Mn2nc2 #compsci #datascience #math #stem #mathchat

2014-07-23 02:37:42

fawnpnguyen tweeted: @fawnpnguyen

@mr_stadel @karimkai @ddmeyer @robertkaplinsky + ages will disappear from younger than 18. Stock up.

2014-07-23 02:26:24

fawnpnguyen tweeted: @fawnpnguyen

@mr_stadel @karimkai @ddmeyer @robertkaplinsky I think I know the 18 well enough and can definitely tell it from the 12. Also heard the +

2014-07-23 02:26:01

andrescaicedo tweeted: @andrescaicedo

Of course, it would be nicer if "Piyush" mentioned explicitly the journal in question. It may just be one of the obviously predatory ones.

2014-07-23 02:13:38

ricardosaenz tweeted: @ricardosaenz

RT @FiveThirtyEight: The @RedSox are much better than their record would have us believe. http://t.co/Eqvej13bjq http://t.co/s1MepvQ98S

2014-07-23 02:10:32

andrescaicedo tweeted: @andrescaicedo

Ridiculous. http://t.co/wje4b9vayl

2014-07-23 02:07:12

j_lanier tweeted: @j_lanier

2014-07-23 01:57:22

MrHonner tweeted: @MrHonner

@JohnDCook I think about, and do, math on the subway all the time. I'm pretty sure it encourages people to leave me alone.

2014-07-23 01:16:55

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