I know I’d implied I was off ’til Monday, but Peter Coles has written an important post that demands immediate and unqualified endorsement. Sketching two stills from his life as an openly gay man, Coles communicates the progress that has and has not been made in the way differences from the inherited social norms of sexuality are handled within academia and British society.
Archive for January, 2010
In the light
Posted in Politics on January 31, 2010| Leave a Comment »
My weekend reading
Posted in Links, tagged Art, Links, Politics, Sport on January 31, 2010| Leave a Comment »
Links that make the world go round:
- Sanford Schwartz in the NY Review of Books on the Belgian figurative artist Luc Tuymans;
- Anne Enwright casts a restrained but not-quite-dispassionate eye across the moral carnage surrounding Iris Robinson;
- Bernard Keane writes for Crikey on the possibility of a no-frills banking service through Australia Post;
- In case you had forgotten, Keith Windschuttle believes that the history of indigenous Australia has been fabricated by, I don’t know, Robert Manne or something; the third volume of his epic revisionism, on the topic of the Stolen Generations in particular, has just been published and Windschuttle takes to the pages of The Australian to tell us more.
- Manne and Windschuttle may deserve one another, but The Monthly >> Quadrant. Here is John Birmingham in the former regarding the existential malaise of New South Wales.
- Amanda Ripley writes in The Atlantic about a determined investigation into what makes for great teaching at the primary and secondary level.
- And for those with extra time up their sleeves, Yves Smith has plenty more to read.
Enjoy your Australian Open/Australia v. Pakistan ODI coverage. See you Monday!
– JBJ, Berkeley, CA
WMAP 7 cosmological parameter set
Posted in Statistics and Metrics, The Universe on January 29, 2010| 1 Comment »
Your Universe ca. 2010, per the WMAP+BAO+H0[1] maximum likelihood parameter set:
Parameter | WMAP+BAO+H0 ML | |||||
---|---|---|---|---|---|---|
Hubble parameter | h | 0.702 | H0 | 70.2 km/s/Mpc | ||
Dark matter density | Ωch2 | 0.1120 | Ωc | 0.227 | ||
Baryonic matter density | Ωbh2 | 0.02246 | Ωb | 0.0455 | ||
Total matter density | Ωmh2 | 0.1344 | Ωm | 0.272 | ||
Vacuum tension[2] | ΩΛ | 0.728 | ||||
Amplitude of curvature perturbation at k = 0.002/Mpc |
Δ2R | 2.45 x 10-9 | ||||
Spectral index of density perturbations |
ns | 0.961 | ||||
Size of linear density fluctuation at 8 Mpc/h |
σ8 | 0.807 | ||||
Redshift of matter– radiation equatlity |
zeq | 3196 | ||||
Age of the Universe | t0 | 13.78 Gyr |
Parameters fit directly from the data are shown in a slightly different colour; all the others have been derived from the fit parameters using the usual definitions. The determination of zeq is carried out using the WMAP 7-year data on its own. The two papers in which these figures are given are:
Larson et al. (2010), arXiv:1001.4635
Komatsu et al. (2010), arXiv:1001.4538
These papers contain many other numbers: in particular, for extensions to ΛCDM cosmology, such as neutrino species, non-zero spatial curvature and dark energy that is not the cosmological constant. I expect some of the parameters mentioned there and not here—particularly the fNLstatistics of non-Gaussianity—to gain more public attention in the next decade as observations begin to determine the properties of the cosmological inflation that occurred in the very early Universe.
A final note: I’ve written this post only because these numbers are not written on an actual webpage—they are all in pdf or postscript files. But, it also gives me a chance to congratulate the WMAP team on their ongoing achievement.
Footnotes
1. Riess, A. et al. (2009), ApJ 699 539, arXiv:0905.0695
2. Dark energy, or, as assumed here, the cosmological constant.
The pleasures of chess
Posted in Brain, Creativity, Puzzle, Sport on January 28, 2010| 5 Comments »
Garry Kasparov this month thinks about reviewing something-or-other in the New York Review of Books, becoming happily diverted into a discussion of what makes chess truly interesting. (I draw also from some recent conversations with S. O. Killmier.)
The big point: chess is not about who can see the most moves ahead. Computers (and humans) that win by doing this are simply winning by brute force, rather than by intelligence; in the article Kasparov memorably denigrates his result against Deep Blue as ‘losing to a $10 million alarm clock.’ If one insists that the only purpose of chess is to win, then brute force seems a very successful, though by no means infallible, way to do this. I’d like to spend a little time describing just why it isn’t fool-proof; and a lot of time showing why victory in chess is less than half the point.
Imagine you are a chess computer; in fact, imagine you are a chess computer with limitless computational power. Now here is a famous chess position—find the winning move:
Barnes + 1
Posted in The Universe on January 28, 2010| 1 Comment »
I’ll let Luke post more extensively on this when time permits, but Berni, Luke & their family welcomed a new addition today, Rosalie Joy Barnes.
Congratulations to the parents!
Genus analogues
Posted in Mathematics, Physics, Statistics and Metrics, The Universe on January 26, 2010| 6 Comments »
N.b. This is a technical post, written to illustrate a question I believe to be interesting to some colleagues outside my particular discipline. I am accutely aware of its shortcomings as expository work, and pedagogical criticism is almost as welcome as an attempt to engage with the question at hand.
The other coincidence problem
Posted in Amusing, Creativity, Mathematics, Physics, The Universe on January 26, 2010| 2 Comments »
J. S. Bloom points out:
so putting constraints on the evolution of the fine structure constant away from its present value. With no apologies whatsoever to xkcd.