Mathematics posts
- September 13, 2010
- 04:04 PM
- 1,362 views
Scientific hubris, or: Everything you thought you knew about straight line fits is wrong
by sarah in One Small Step
Think you’ve got your least squares down to a tee? Think again. In a paper posted to the Arxiv in late August, David Hogg of NYU and his collaborators take us to task on our sloppy data fitting habits. And he’s not in the mood to mince his words. It is conventional to begin any [...]... Read more »
David W. Hogg, Jo Bovy, & Dustin Lang. (2010) Data analysis recipes: Fitting a model to data. Arxiv . arXiv: 1008.4686v1
- August 29, 2010
- 04:45 PM
- 697 views
A Mathematical Description of Cell Aggregate Mechanical Deformation
by Michael Long in Phased
Luigi Preziosi (Politecnico di Torino, Italy) and coworkers have developed a mathematical model for the mechanical stress experienced by cell aggregates, relevant to cellular function in normal health (blood flow) and disease (cancer). This news feature was written on August 29, 2010.... Read more »
Preziosi, L., Ambrosi, D., & Verdier, C. (2010) An elasto-visco-plastic model of cell aggregates. Journal of Theoretical Biology, 262(1), 35-47. DOI: 10.1016/j.jtbi.2009.08.023
- August 27, 2010
- 10:28 AM
- 1,132 views
Please explain the end of kin selection
by Zen Faulkes in NeuroDojo
As an evolutionary biologist, I’m very familiar with the idea of kin selection. When I saw a paper titled “The evolution of eusociality” in the table of contents of Nature, and read the abstract saying, “Kin selection? Don’t need it,” I thought to myself, “Ooooh, this is big.”
I’ve read blog posts about it on Plektix and Wired. I listened to first author Martin Novak being interviewed on the Nature podcast.
Novak does a good job of explaining why kin selection is invoke........ Read more »
Nowak, M., Tarnita, C., & Wilson, E. (2010) The evolution of eusociality. Nature, 466(7310), 1057-1062. DOI: 10.1038/nature09205
- August 26, 2010
- 03:35 AM
- 739 views
Global Temperature Proxy Reconstructions ~ now with CO2 forcing
by apeescape in mind of a Markov chain
Previously, I did a simple Bayesian projection of recent temperature using proxy data and the methods shown in McShane and Wyner (2010). I showed that when you take out the last 30 years of data (1969~1998), the projection does not track the recent uptick in temperatures well. The “projection” is a simple unparametric bootstrap which [...]... Read more »
BLAKELEY B. MCSHANE AND ABRAHAM J. WYNER. (2010) A STATISTICAL ANALYSIS OF MULTIPLE TEMPERATURE PROXIES: ARE RECONSTRUCTIONS OF SURFACE TEMPERATURES OVER THE LAST 1000 YEARS RELIABLE?. Annals of Applied Statistics, 4(3). info:/
- August 24, 2010
- 11:54 AM
- 869 views
Differentiating Skill and Luck in Financial Markets with Streaks
by Samuel Arbesman in arbesman.net
Speaking of luck, we just released a paper onto SSRN about luck and skill entitled Differentiating Skill and Luck in Financial Markets with Streaks. This paper, which I worked on with Andrew Mauboussin (a brilliant high school student who worked in our lab this summer), examines the relationship between skill and luck using mutual fund [...]... Read more »
Andrew Mauboussin, & Samuel Arbesman. (2010) Differentiating Skill and Luck in Financial Markets with Streaks. SSRN: http://ssrn.com/abstract. info:/
- August 22, 2010
- 04:10 AM
- 666 views
Global Temperature Proxy Reconstructions ~ Bayesian extrapolation of warming w/ rjags
by apeescape in mind of a Markov chain
There are a bunch of “hockey sticks” that calculate past global temps. through the use of proxies when instrumental data is absent. There is a new one out there by McShane and Wyner (2010) that’s creating quite a stir in the blogosphere (here, here, here, here). The main take out being, that the uncertainty is [...]... Read more »
BLAKELEY B. MCSHANE AND ABRAHAM J. WYNER. (2010) A STATISTICAL ANALYSIS OF MULTIPLE TEMPERATURE PROXIES: ARE RECONSTRUCTIONS OF SURFACE TEMPERATURES OVER THE LAST 1000 YEARS RELIABLE?. Annals of Applied Statistics, 4(3). info:/
Mann, M., Zhang, Z., Hughes, M., Bradley, R., Miller, S., Rutherford, S., & Ni, F. (2008) Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia. Proceedings of the National Academy of Sciences, 105(36), 13252-13257. DOI: 10.1073/pnas.0805721105
- August 20, 2010
- 04:10 PM
- 727 views
Genome-Scale Epigenetic Marker Detection Across Populations
by Michael Long in Phased
Lior Pachter (University of California at Berkeley, United States) and coworkers have developed MetMap software for uncovering epigenetic data hidden by standard MethylSeq analysis, which will advance our understanding of the role of epigenetics in human health and medicine. This news feature was written on August 20, 2010.... Read more »
Singer, M., Boffelli, D., Dhahbi, J., Schoenhuth, A., Schroth, G. P., Martin, D. I. K., & Pachter, L. (2010) MetMap Enables Genome-Scale Methyltyping for Determining Methylation States in Populations. PLoS Computational Biology, 6(8). DOI: 10.1371/journal.pcbi.1000888
- August 19, 2010
- 07:30 AM
- 584 views
Numbers on the Brain: Neurobiology of Mathematics
by Jason Goldman in Child's Play
Nearly everyone has heard of developmental dyslexia – a learning disorder characterized by poor reading skills despite otherwise sufficient schooling – but have you heard of developmental dyscalculia? Many people have not. Here is part 4 in a week-long series on this lesser-known learning disorder. Case-studies of patients with various brain lesions have demonstrated the [...]... Read more »
Ardila A, & Rosselli M. (2002) Acalculia and dyscalculia. Neuropsychology review, 12(4), 179-231. PMID: 12539968
Dehaene, S. (2004) Arithmetic and the brain. Current Opinion in Neurobiology, 14(2), 218-224. DOI: 10.1016/j.conb.2004.03.008
Isaacs EB, Edmonds CJ, Lucas A, & Gadian DG. (2001) Calculation difficulties in children of very low birthweight: a neural correlate. Brain : a journal of neurology, 124(Pt 9), 1701-7. PMID: 11522573
Molko N, Cachia A, Rivière D, Mangin JF, Bruandet M, Le Bihan D, Cohen L, & Dehaene S. (2003) Functional and structural alterations of the intraparietal sulcus in a developmental dyscalculia of genetic origin. Neuron, 40(4), 847-58. PMID: 14622587
Dehaene, S, Piazza, M, Pinel, P, & Cohen, L. (2003) Three Parietal Circuits for Number Processing. Cognitive Neuropsychology, 487-506. info:/
- August 19, 2010
- 06:00 AM
- 1,334 views
Evolution of Colour Terms: 3 Perceptual Constraints
by Sean Roberts in A Replicated Typo 2.0
Continuing my series on the Evolution of Colour terms, this post reviews evidence for perceptual constraints on colour terms. For the full dissertation and for references, go here.
The perceptual space that results from the processing of opponent colours is non-uniform (see Figure below), meaning that there are optimal ways to describe it (Jameson & D’Andrade, . . . → Read More: Evolution of Colour Terms: 3 Perceptual Constraints... Read more »
Jameson, K., & D'Andrade, R.G. (1997) It's not really Red, Green, Yellow, Blue: An Inquiry into cognitive color space. Color Categories in Thought and Language. DOI: 10.1017/CBO9780511519819.014
Regier, T., Kay, P., & Khetarpal, N. (2007) Color naming reflects optimal partitions of color space. Proceedings of the National Academy of Sciences, 104(4), 1436-1441. DOI: 10.1073/pnas.0610341104
Liljencrants, J., Lindblom, B., & Lindblom, B. (1972) Numerical Simulation of Vowel Quality Systems: The Role of Perceptual Contrast. Language, 48(4), 839. DOI: 10.2307/411991
DEBOER, B. (2000) Self-organization in vowel systems. Journal of Phonetics, 28(4), 441-465. DOI: 10.1006/jpho.2000.0125
Buchsbaum, G. (2002) Color categories revealed by non-negative matrix factorization of Munsell color spectra. Vision Research, 42(5), 559-563. DOI: 10.1016/S0042-6989(01)00303-0
- August 18, 2010
- 09:30 AM
- 488 views
Developmental Dyscalculia Explained: Strategy, Memory, Attention
by Jason Goldman in Child's Play
Nearly everyone has heard of developmental dyslexia – a learning disorder characterized by poor reading skills despite otherwise sufficient schooling – but have you heard of developmental dyscalculia? Many people have not. Here is part 3 in a week-long series on this lesser-known learning disorder. (See parts one, and two, and a companion post at [...]... Read more »
Gallistel CR, & Gelman R. (1992) Preverbal and verbal counting and computation. Cognition, 44(1-2), 43-74. PMID: 1511586
Siegler, R. (1994) Cognitive Variability: A Key to Understanding Cognitive Development. Current Directions in Psychological Science, 3(1), 1-5. DOI: 10.1111/1467-8721.ep10769817
Geary, D. (1993) Mathematical disabilities: Cognitive, neuropsychological, and genetic components. Psychological Bulletin, 114(2), 345-362. DOI: 10.1037/0033-2909.114.2.345
Butterworth, B. (2005) The development of arithmetical abilities. Journal of Child Psychology and Psychiatry, 46(1), 3-18. DOI: 10.1111/j.1469-7610.2004.00374.x
Rosenberg PB. (1989) Perceptual-motor and attentional correlates of developmental dyscalculia. Annals of neurology, 26(2), 216-20. PMID: 2774508
- August 5, 2010
- 06:52 PM
- 1,242 views
R and Google Earth ~ comparing tuna tracks vs. Gulf of Mexico oil spill extent
by apeescape in mind of a Markov chain
There is a lot of interest in how the Gulf of Mexico oil gusher will affect the ecosystem and its marine species. One such species is the Western Atlantic bluefin tuna that holds the Gulf of Mexico as one of its major spawning grounds. Recent tag data show that the location of the gusher is [...]... Read more »
Teo SL, & Block BA. (2010) Comparative influence of ocean conditions on yellowfin and atlantic bluefin tuna catch from longlines in the gulf of Mexico. PloS one, 5(5). PMID: 20526356
- August 4, 2010
- 03:44 PM
- 732 views
Real Time fMRI
by Neuroskeptic in Neuroskeptic
Wouldn't it be cool if you could measure brain activation with fMRI... right as it happens?You could lie there in the scanner and watch your brain light up. Then you could watch your brain light up some more in response to seeing your brain light up, and watch it light up even more upon seeing your brain light up in response to seeing itself light up... like putting your brain between two mirrors and getting an infinite tunnel of activations.Ok, that would probably get boring, eventually. But th........ Read more »
Hinds, O., Ghosh, S., Thompson, T., Yoo, J., Whitfield-Gabrieli, S., Triantafyllou, C., & Gabrieli, J. (2010) Computing moment to moment BOLD activation for real-time neurofeedback. NeuroImage. DOI: 10.1016/j.neuroimage.2010.07.060
- July 30, 2010
- 11:00 AM
- 621 views
Measuring Synchrony - pt 2 of ??
by Brandon Goodell in Bored Lunatic
This is the second in a multi-part series analyzing the paper linked below. The paper uses several measures of synchrony and tests them against some real-world data to compare their performance. Today I will be talking about three different measures of nonlinear interdependence between two signals, all of which are based on nearest neighbors.
The main thing here is that the frequency coherence method of measuring synchrony primarily measures linear interdependency. In othe........ Read more »
Quian Quiroga, R., Kraskov, A., Kreuz, T., & Grassberger, P. (2002) Performance of different synchronization measures in real data: A case study on electroencephalographic signals. Physical Review E, 65(4). DOI: 10.1103/PhysRevE.65.041903
- July 20, 2010
- 07:09 AM
- 931 views
Why you REALLY can’t trust small studies: the small study effect
by Michael Slezak in Good, Bad, and Bogus
You’ll often see loony zealots refer you to a study showing how effective their preferred treatment is — there usually is some small study supporting the use of almost any treatment.
You’ll also often hear people reply that the study was only small, so shouldn’t be trusted. But why shouldn’t you trust small studies? Sure, they [...]... Read more »
Nüesch E, Trelle S, Reichenbach S, Rutjes AW, Tschannen B, Altman DG, Egger M, & Jüni P. (2010) Small study effects in meta-analyses of osteoarthritis trials: meta-epidemiological study. BMJ. PMID: 20639294
- July 19, 2010
- 09:32 AM
- 559 views
Measuring Synchrony - pt 1 of ??
by Brandon Goodell in Bored Lunatic
This is the first in a multi-part series analyzing the paper linked below. The paper uses several measures of synchrony and tests them against some real-world data to compare their performance. Today I will be talking about the frequency-coherence measure of synchrony.
I really love being a scientist. The coolest bit about research, as far as I can tell, is that it's hard. You are exploring the unknown. This paper is exploring the unknown - in the past two decade,........ Read more »
Quian Quiroga, R., Kraskov, A., Kreuz, T., & Grassberger, P. (2002) Performance of different synchronization measures in real data: A case study on electroencephalographic signals. Physical Review E, 65(4). DOI: 10.1103/PhysRevE.65.041903
- July 18, 2010
- 12:07 AM
- 1,012 views
Cherry Picking to Generalize ~ retrospective meta-power analysis using Cohen’s f^2 of NASA temp visualization
by apeescape in mind of a Markov chain
Previously, I plotted a grid of NASA GISS global temps in ggplot2 to show general trends by the brute force method. Here, I will again use the brute force method to do a simple power analysis on a portion of the data (data here). The general aim is to figure out what the minimum sample [...]... Read more »
Thomas, L. (1997) Retrospective Power Analysis. Conservation Biology, 11(1), 276-280. DOI: 10.1046/j.1523-1739.1997.96102.x
- July 16, 2010
- 11:53 AM
- 535 views
Phase synchronization
by Brandon Goodell in Bored Lunatic
Consider two pendula (penduli? pendulums?) that are on a bit of a wobbly table, oscillating back and forth.
Eventually, they synchronize. Once a huge mystery to physics, the fact that placing two pendulums on the same surface causes minute vibrations to transmit through that surface, causing the devices to become weakly coupled. The result is that, after a sufficiently long period of time swinging back and forth, the two pendulums become fully synchronous.
The Scholarpedia article, "Phase ........ Read more »
Izhikevich, E., & Ermentrout, B. (2008) Phase model. Scholarpedia, 3(10), 1487. DOI: 10.4249/scholarpedia.1487
- July 16, 2010
- 04:23 AM
- 1,072 views
‘Gravity doesn’t exist’, says philosophically naive scientist/journalist
by Michael Slezak in Good, Bad, and Bogus
Reports of a physicist “taking on gravity” have recieved a bit of attention recently, with a New York Times article outlining Erik Verlinde’s idea that gravity is an emergent property of thermodynamics.
I think it’s great that the piece was written — even though apparently it hasn’t excited any physicists since the start of the year. Regardless [...]... Read more »
Erik P. Verlinde. (2010) On the Origin of Gravity and the Laws of Newton. arxiv.org. arXiv: 1001.0785v1
Bertrand Russell. (1912) On the notion of cause. Proceedings of the Aristotelian Society. info:other/
- July 9, 2010
- 09:35 PM
- 1,060 views
Log Normal Distributions in Ecology ~ multiplications complications
by apeescape in mind of a Markov chain
The normal distribution is the “norm” when applying statistics to data. It is simple to interpret, simple to predict, simple to optimize, convenient software-wise and analytically elegant. But in many applications, this modeling assumption may not be optimal. The first is that the normal distribution doesn’t have a zero bound. In ecology, the data is [...]... Read more »
LIMPERT, E., STAHEL, W., & ABBT, M. (2001) Log-normal Distributions across the Sciences: Keys and Clues. BioScience, 51(5), 341. DOI: 10.1641/0006-3568(2001)051[0341:LNDATS]2.0.CO;2
- July 7, 2010
- 03:30 AM
- 1,346 views
Top Ten Excuses for World Cup Football Failures (with citations)
by Duncan Hull in O'Really?
Football fever grips the globe as we reach the final stages of the 2010 FIFA World Cup in South Africa. Alongside the traditional game where one winning team takes all, leaving 31 losing teams to go home earlier than expected, there is another competition running in parallel. Which losing team can come up with the [...]... Read more »
Travis, K. (2010) Scoring a Career in Sports Science. Science. DOI: 10.1126/science.caredit.a1000067
Lucifora, C., & Simmons, R. (2003) Superstar Effects in Sport: Evidence From Italian Soccer. Journal Of Sports Economics, 4(1), 35-55. DOI: 10.1177/1527002502239657
Zak, P., Kurzban, R., Ahmadi, S., Swerdloff, R., Park, J., Efremidze, L., Redwine, K., Morgan, K., & Matzner, W. (2009) Testosterone Administration Decreases Generosity in the Ultimatum Game. PLoS ONE, 4(12). DOI: 10.1371/journal.pone.0008330
Elmar Bittner, Andreas Nussbaumer, Wolfhard Janke, & Martin Weigel. (2006) Football fever: goal distributions and non-Gaussian statistics. Eur. Phys. J. B 67, 459 (2009). arXiv: physics/0606016v1
Goff, J., & Carré, M. (2010) Soccer ball lift coefficients via trajectory analysis. European Journal of Physics, 31(4), 775-784. DOI: 10.1088/0143-0807/31/4/007
Kranjec, A., Lehet, M., Bromberger, B., & Chatterjee, A. (2010) A Sinister Bias for Calling Fouls in Soccer. PLoS ONE, 5(7). DOI: 10.1371/journal.pone.0011667
Abell, J. (2010) ‘They seem to think “We're better than you”’: Framing football support as a matter of ‘national identity’ in Scotland and England. British Journal of Social Psychology. DOI: 10.1348/014466610X514200
Wayne C. Naidoo, & Jules R. Tapamo. (2006) Soccer video analysis by ball, player and referee tracking. SAICSIT '06: Proceedings of the 2006 annual research conference of the South African institute of computer scientists and information technologists on IT research in developing countries. DOI: 10.1145/1216262.1216268
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