March 27, 2014

"Tits of the World" Poster Process.

(via notrare)

March 26, 2014
Shrout & Fleiss’s ICC in mixed model form

Shrout & Fleiss give guidelines for calculating intraclass correlation coefficients for estimating interrater reliability and agreement. The original paper shows how to calculate them using ANOVA but they can also be estimated in a mixed model framework. Noting these down so I remember them

1. "Repeatability"
$y = a + e$
$ICC(1, k) = \frac{\sigma_a^2}{\sigma_a^2 + \frac{\sigma_e^2}{k}}$
2. "Agreement"
$y = a + r + \epsilon$
$ICC(2, k) = \frac{\sigma_a^2}{\sigma_a^2 + \frac{\sigma_r^2 + \sigma_\epsilon^2}{k}}$
3. "Consistency"
$y = a + r + \epsilon$
$ICC(3, k) = \frac{\sigma_a^2}{\sigma_a^2 + \frac{\sigma_\epsilon^2}{k}}$

March 7, 2014

Good book.

(Source: bbww, via unfinished-photography)

February 24, 2014

via Fat Birds

February 17, 2014

February 13, 2014
"Every speciality changes its classification of illnesses every few years, as we learn more about illnesses, but only psychiatry gets abuse for doing so."
February 6, 2014

Having done some research recently on collies, I like this.

(Source: scancity)

February 5, 2014
"Think of overfitting as memorizing as opposed to learning."

— James Faghmous , New to Machine Learning? Avoid these three mistakes

February 1, 2014
Feasibility and Uncertainty in Behavior Genetics for the Nonhuman Primate

M. J. Adams International Journal of Primatology February 2014, Volume 35, Issue 1, pp 156-168 doi: 10.1007/s10764-013-9722-8

Nonhuman primates are good species to study for understand the genetic underpinnings of behavior, especially because their behaviors are so similar to our. One reason that primates are good to study is because they are individually identifiable and we tend to know which individuals are related (or we can discover this using genotyping).

However, studying primates offers several challenges. The main one is that when studying nonhuman primates the sample sizes (dozens or at most hundreds) are much smaller than what is typical in studies of humans (hundreds to tens of thousands). This small sample size diminishes statistical power and limits the types of questions that can be investigated.

I conducted some simulations to see just how gloomy the prospects are. I found that statistical power can be increased slightly by multiple measurements of each individual, something that is feasible since primates are long-lived.

Abstract

The analysis of phenotypic covariances among genetically related individuals is the basis for estimations of genetic and phenotypic effects on phenotypes. Beyond heritability, there are several other estimates that can be made with behavior genetic models of interest to primatologists. Some of these estimates are feasible with primate samples because they take advantage of the types of relatives available to compare in primate species and because most behaviors are expressed orders of magnitude more often and in a greater variety of contexts than morphological or life-history traits. The hypotheses that can be tested with these estimates are contrasted with hypotheses that will be difficult to achieve in primates because of sample size limitations. Feasible comparisons include the proportion of variance from interaction effects, the variation of genetic effects across environments, and the genetics of growth and development. Simulation shows that uncertainty of genetic parameters can be reduced by sampling each individual more than once. Because sample sizes are likely to remain relatively small in most primate behavior genetics, expressing uncertainty in parameter estimates is needed to move our inferences forward.

January 25, 2014
"Practically no experimental work has been done upon individual differences and family resemblances in animal behavior. In most cases the behaviorist has been content to study the mass reaction of a group of animals to external stimuli, and in the main, has not attempted to treat the variability of his group because of the relatively small number of animals tested."

— Halsey Bagg, 1920, Archives of Genetics Mono. Vol 43, p.1 (via Rosalind Arden)

2:46pm  |   URL: http://tmblr.co/Z23PQy15O3-iG
Filed under: genetics variation
January 24, 2014

Jose Vazquez
The tower and the park

The Arts Tower and Western Bank Library at the University of Sheffield.

January 23, 2014

"Hurrah then for confusion and mystery in medicine."

A mesmeric physician taking advantage of his female patient. Colour lithograph, 1852
Wellcome Images L0034922

January 21, 2014
"…the shy-animal mental model of experimentation. The effect is there; you just need to create the right circumstances to coax it out of its hiding place."
January 18, 2014

Never Trust Passerine Nomenclature by Albertonykus via @hylopsar.

January 15, 2014

March 25, 1984 — see The Complete Peanuts 1983-1986