Reading
Arxiv has several articles on the EM-algorithm from J. Statistical Science unknown, unknown. What makes this distinct from applying any traditional optimization routine (Nelder-Mead, simulated annealing, etc) to the likelihood function? Just in that it determines the probability distribution as well as maximum?
UPDATE ON EM: brief discussion with Graham, Peter, Yaniv on this, now my impression is: Not necessarily get the distribution, but doesn’t just generically take a function and minimize it, but may not calculate the likelihood at each step. Handles missing values, simulate the data. We’ll take a closer look at this in our Algorithms discussion group.
Also from the arxiv, nice article by Nick Barton and colleagues on the role statistical mechanics has played in evolutionary biology.
Interesting work on the arxiv on critical transitions from Christian, a post-doc in Thilo Gross’s group at Max Planck Complex Systems, Dresden. Also meaning to look over there generalized models in food webs paper (Gross et. al. 2009).
Looks like a fantastic article on estimating diversification (speciation/extinction) rates in PNAS(Stadler, 2011), and an accompanying package, TreePar (which actually looks like it’s been on CRAN since last June).
Looking over this paper led me to a few others also by Tanja, discussing some of the challenges of simulating(Stadler, 2011) and sampling trees(Hartmann et. al. 2010).
See TreePar discussion in later post.
References
Gross T, Rudolf L, Levin S and Dieckmann U (2009). “Generalized Models Reveal Stabilizing Factors in Food Webs.” Science, 325. ISSN 0036-8075, https://dx.doi.org/10.1126/science.1173536.
Stadler T (2011). “Mammalian Phylogeny Reveals Recent Diversification Rate Shifts.” Proceedings of The National Academy of Sciences, 108. ISSN 0027-8424, https://dx.doi.org/10.1073/pnas.1016876108.
Stadler T (2011). “Simulating Trees With A Fixed Number of Extant Species.” Systematic Biology, 60. ISSN 1063-5157, https://dx.doi.org/10.1093/sysbio/syr029.
Hartmann K, Wong D and Stadler T (2010). “Sampling Trees From Evolutionary Models.” Systematic Biology, 59. ISSN 1063-5157, https://dx.doi.org/10.1093/sysbio/syq026.