Stephen Chu’s White Roof Proposal and Rush Limbaugh’s Response

White roofing on urban row homes in Philadelphia

It does not surprise me that Rush Limbaugh would think that Energy Secretary Stephen Chu’s proposal to paint flat roofs white is idiotic, but I found it rather amusing that he couldn’t even figure out how reflection works on his radio talk show this morning. This is a very simple idea, light colors are brighter or lighter than dark colors because they reflect more light. The key is to understand that light is energy and light that impinges upon dark surfaces is far more likely to be absorbed and converted to kinetic energy, a.k.a. heat. Although I’m not sure, I bet the reason for only painting flat roofs white is because slanted roofs will reflect the light such that it will travel through far more of the earth’s atmosphere and therefore almost certainly be absorbed by the air, whereas a flat roof will reflect the light nearly vertically and thus the photons will be far more likely to escape our atmosphere back out to space. The solution is simple and cheap, yet elegant in its simplicity.

I feel that anybody who has completed a high school education in this country should be able to come up with the explanation that I just gave above, but the sad fact is that probably the majority of American’s could not give such an explanation, despite the fact that the overwhelming majority of Americans have completed high school. Science has been the hallmark of the advancement of all civilizations, why is “illiteracy” in science (and innumeracy) so acceptable in our society? Although left wing extremists will jump at the opportunity to make Rush look stupid, the general public won’t care. Although it is possible that Rush was being disingenuous and really did understand the simple ideas behind the proposal, but feigned ignorance for political reasons, I am more inclined to believe that he was being honest when he said he didn’t understand how it works.

We really need to look at how we teach in this country, and start experimenting with radical new approaches because this perfectly illustrates how inadequate current methods are. I realize changes in how science is taught have been made since Mr. Limbaugh attended school, but I am quite certain that most recent graduates would respond similarly.

Books: “Euler’s Gem The Polyhedron Formula and the Birth of Topology” by David S. Richeson

This book is a beautifully illustrated gem! It examines Euler’s famous formula: V-E+F=2 which holds for all polyhedra or surfaces which are topologically equivalent to the sphere. The formula is an example of a topological invariant, something which can be computed for any surface, and thus allows one to categorize surfaces. The book also covers the famous classification theorem which categorizes all surfaces as either homeomorphic (topologically equivalent) to a sphere, n-handled torus, or sphere with n cross-caps (projective plane). Next it dives into knot theory and Seifert surfaces, before moving on to the interplay between topology and geometry, and ends by mentioning homology and how topology is done in higher dimensions.

Steven Strogatz guest blogs on the New York Times

Steven Strogatz, a mathematician at Cornell University and the author of a really cool book on chaotic dynamical systems was asked to guest blog at the New York Times today. He has written a short but interesting piece about power laws originating in biological systems and even in cities.

Creating Printable PDF Flash Cards Using LaTeX

This post details how to make high quality, printable flash cards like I have available at my web site. I am assuming you are using Ubuntu Linux. I did this on Ubuntu 8.04 (Hardy Heron), but it might work on some previous and later versions as well.

First you want to install LaTeX, plus Andrew Budge’s flashcards package. Open a command terminal and type in the following command to install TeX and LaTeX. The flashcards package resides in the texlive-latex-extra Ubuntu package.


$ sudo apt-get install texlive texlive-latex-extra


I also recommend installing Kile which is a great program for editing TeX/LaTeX documents. You can do this with the following command. Depending on your system configuration, apt-get might require you to install several extra packages. The following is optional:


$ sudo apt-get install kile


At this point, if you try to compile a latex document that uses the flashcards package, you’ll get the following error:


! Package geometry Error: You must set \paperwidth properly.


To fix this, we need to create a small file called geometry.cfg, which tells the geometry packages which type of paper we will be using. Create the file using the following command:


$ sudo gedit /usr/share/texmf-texlive/tex/latex/geometry/geometry.cfg


Now copy and paste the following into gedit, save the file and exit from gedit.


%%
%% This is file `geometry.cfg',
%% generated with the docstrip utility.
%%
%% The original source files were:
%%
%% geometry.dtx (with options: `config')
%%
%% File: geometry.dtx Copyright (C) 1996-2002 Hideo Umeki
%% (hideo.umeki@toshiba.co.jp)
%%
%% This package may be distributed under the terms of the LaTeX
%% Project Public License, as described in lppl.txt in the base
%% LaTeX distribution, either version 1.2 or (at your option)
%% any later version.
%%

%% Uncomment and edit the line below to set default options.
\ExecuteOptions{letterpaper,dvips}

\endinput
%%
%% End of file `geometry.cfg'.


Now, you should be able to compile a LaTeX document that uses the flashcards package without errors, but there will be some warnings. To fix the warnings, we need to change one line in flashcards.cls.


$ sudo gedit /usr/share/texmf-texlive/tex/latex/flashcards/flashcards.cls


The following diff command shows the change you need to make:


$ diff -ru flashcards.cls.bak flashcards.cls
--- flashcards.cls.bak 2009-01-26 17:15:27.000000000 -0700
+++ flashcards.cls 2009-01-26 19:43:57.000000000 -0700
@@ -83,7 +83,7 @@
top=\topoffset,
left=\oddoffset,
right=\evenoffset,
- twosideshift=\oddevenshift,
+ twoside=true,
bottom=0.0in,
noheadfoot}
\ifthenelse{\boolean{flashcards@dvips}}{\geometry{dvips}}{}


Now you should be able to compile a LaTeX document without any errors or warnings, excepting for any errors in your own markup of course.

Good Introduction to Emacs

I stumbled upon a short but useful introduction to emacs on the web. It has lots of screenshots to demonstrate the different commands. It even touches upon development tools like gdb and diff.

Books: “Particle Physics A Very Short Introduction” by Frank Close

I found this book in the library the other day and found it to be a very good introduction to the basics of particle physics. I liked the fact that it explains the basics of the experimental side of particle physics as well as introducing the three families of leptons and quarks. Too often, popular science books explain the various subatomic particles with out giving you any idea of how we actually know of their existence. Because of this, I think disbelief tends to creep in. But Close does an excellent job of explaining the basics of how accelerators operate and also the basics of how detectors work. And he does all this in only 129 pages! Very short indeed, and highly recommended.

Algebraic Geometry: “Ideals, Varieties, and Algorithms” C++ Code

I did an REU (Research Experience for Undergraduates) this summer and we used the textbook “Ideals, Varieties, and Algorithms” (isbn 978-0-387-35650-1) by David Cox, John Little, and Donal O’Shea. As the title mentions, algorithms are an important tool in the study of varieties via their corresponding algebraic ideals. One of the main tools used in algebraic geometry is what is known as a Groebner basis, which is somewhat akin to a basis set in Linear Algebra. Anyway, I wrote some C++ code which implements a few of the algorithms in the book, but stops short of implementing Buchberger’s algorithm for computing a Groebner basis. The code should be useful as a starting point because it implements a Monomial class and a Polynomial class both with lots of useful methods thus eliminating the drudgery of implementing the book’s algorithms in C++.

The code can be found at: my web site as a gzipped tarball. Please let me know if you find it useful. I developed the code on an Ubuntu Linux machine, but it is generic enough that it should compile on any platform. You will need to read the README to understand the simple input, output format.

Run any GNU/Linux app on Windows without any virtualization

Free Software Magazine has an excellent article on how to Run any GNU/Linux app on Windows without any virtualization.

It explains how to install, setup and use the free Xming X Window server for Windows and also how to use SSH from the command line. It also includes information on how to enable SSH access into an Ubuntu machine.

Iterated Function Systems and Fractals

This code generates fractals based upon an iterated function system (IFS). Several input files and a Makefile are included. The code is written in C++, and distributed as a tarball. I did this for a class at the University of Utah, but it is based upon a homework assignment for a computer graphics class at MIT (6.837).

Below is the famous Barnsley fern which was generated by an IFS with just four transforms!

New and Improved Sierpinski Triangle C++ Code

I modified my Sierpinski triangle code so that it now allows you to adjust the contraction mapping constant. Normally one uses a contraction mapping constant of 1/2 but if you invert that and instead use an expansion mapping constant of 2, then you get the following pretty picture.

The New College Try – New York Times

The New York Times has an excellent op-ed piece today on college admissions. Read the article, and you’ll see why test prep centers like Kaplan are doing so well.

Strategy Letter VI – Joel on Software

Joel Spolsky has an excellent essay on his blog about AJAX web apps and where they’re headed. The essay is entitled Strategy Letter VI – Joel on Software and I highly recommend it!

I used to be very enthusiastic about a startup that originated at MIT called Curl Corporation that did much of what Joel talks about with one major exception, instead of targeting JavaScript, they targeted their own runtime. Now that has the major disadvantage that users must download the runtime in order to run client-side Curl code, but the widespread adoption of Flash (which sucks in comparison because it was designed for visual effects) leads me to believe that if they had decided to freely distribute their runtime (for commercial as well as non-commercial use), then they would be rulers of the web by now. Their language is fairly Lispy like Joel talks about in his essay, and was a joy to use, but alas, they decided to take the short-term route and market their technology to large corporations for intranet applications. I tend to think that if they had taken the long-term strategy of targeting the entire web, then we would all be using Curl now and enjoying very rich client-side web apps instead of bickering about how to best AJAXify your web-site/application.

At this point in time, I think Joel is spot-on about the need to target JavaScript, instead of creating a new runtime, because that avoids the chicken and egg dilemma. But the devil is in the details. It may be a considerable challenge to seamlessly target Microsoft’s, Apple’s and Mozilla’s JavaScript engines.

Classes I’m Taking Fall Semester 2007

Here are the classes I’m taking this fall:

• Introduction to Complex Analysis
• Introduction to Topology
• Research Experience for Undergraduates: Metric Spaces, The Contraction Mapping Principle, Fractals and Other Applications

The Subconcious Brain – Who’s Minding the Mind? – New York Times

I found this article in today’s New York Times to be very fascinating:
The Subconcious Brain – Who’s Minding the Mind?

Dark Matter and Particle Physics

Michael Peskin recently posted an article to the arxiv entitled “Dark Matter and Particle Physics”. The article is an almost layman’s guide to how the WIMP model of dark matter might soon be partially validated experimentally at the LHC.

In the article he outlines the reasons why most matter in the universe is dark or in other words does not emit light or radiation, and thus is normally only detected via its gravitational effects. He then goes on to describe the WIMP model for dark matter and its predictions. Next he talks about how the LHC might detect WIMPs:

The discovery of events at the LHC with apparent unbalanced momentum will signal that this accelerator is producing weakly interacting massive particles. However, it would be far from clear that this particle is the same one that is the dominant form of matter in the universe. To demonstrate this, we would need to correlate properties of the WIMP that we observe at the LHC with astrophysical observations.

There are two possible ways to observe WIMPs outside of the LHC. First is the direct approach of observing the scattering of a WIMP from a nucleus in an extremely sensitive detector located deep underground in a mine to minimize noise. The second method is to observe gamma rays emitted from pairs of WIMPS annihilating each other. These gamma rays should have a characteristic spectrum and be most commonly found coming from parts of our galaxy where the concentration of dark matter is highest, namely near the center of the Milky Way.

If the mass of the WIMP seen at the LHC is the same as the mass from astrophysical detection experiments, this will provide strong evidence that the LHC is producing the true particle of dark matter.

Thanks to Hwasung “Mars” Lee for pointing out this article in his blog.

General Public License Version 3: A Legal View

If you would like a great summary of differences between versions 2 and 3 of the GPL check out Mark Radcliffe’s blog post: General Public License Version 3: A Legal View on his blog entitled Law & Life: Silicon Valley.

New RSS Feed for Flash Cards Page

I added an RSS feed to update anyone interested on changes I’ve made to my Math and Physics flash cards page.

Printable “Real Analysis” Theorems Flash Cards

In my last post, I mentioned that I had created some flash cards for Real Analysis that had definitions on them. I recently created a set with many of the relevant theorems, and I will be updating them as the summer progresses. Thanks to Erin Chamberlain for providing the source TeX code for the theorems. You can find them at

http://www.physics.utah.edu/~jasonu/flash-cards/

Enjoy!

Printable “Real Analysis” Flash Cards

I’ve been busy this summer studying Real Analysis, and in the process I’ve made a set of printable flash cards in PDF format. They’re still a work in progress, but I have over 90 cards full of definitions. Cards with theorems on them will probably come some time later. The pictures below show what the typical front and back of a card look like.

Cool Feature on NY Times Website

I was just reading an article on the New York Times entitled “Science of the Soul? ‘I Think, Therefore I Am’ Is Losing Force” and while reading I came across the word “palaver” in the text. Not knowing its meaning I double clicked on it to highlight it so I could easily paste it into Ubuntu’s dictionary, but there was no need. The website popped open a window with the definition for me. Pretty cool! I wonder how long this has been working?