Moments for a bivariate beta distribution

A common choice for a probability distribution of a probability is the beta distribution. It has the required support between 0 and 1, and with its two parameters we can obtain a pretty wide qualitative range for the probability density function. What should we do if we want to create correlated probabilities? We might look for some kind of multivariate generalisation of the beta distribution, … Continue reading Moments for a bivariate beta distribution

Understanding the neigbour-modulated inclusive fitness approach

The goal is to understand Equation 4.2 of Rodrigues and Kokko (2016). To understand the technique, I read through Taylor et al. (2007), and Taylor and Frank (1996), specifically examples 4, 4a and 4b. Very briefly, we begin with a matrix whose elements represent the genetic contribution of class to class . Then for some mutant genic value , the fitness derivative is where is … Continue reading Understanding the neigbour-modulated inclusive fitness approach

Evolution of parochialism

Previously I was reading about identity in Singapore, and I found that the government project of creating a national identity is focused upon creating a cosmopolitan mindset (i.e. one of openness and tolerance of difference), and that this interacts in different ways with the two main groups of foreigners, the ‘foreign talent’ and the ‘foreign worker’. The literature review that I did there was focused … Continue reading Evolution of parochialism

Identity in Singapore, the Internet, and connections to game theory

The following is a literature summary that I undertook as part of my broader interest in modelling social systems, using identity in Singapore as a case study. I should preface all of this by saying that the ideas below are not ‘my own’ as such, but rather my attempt to synthesise the literature and opinions of experts in Singapore. Identity in Singapore Since independence, the … Continue reading Identity in Singapore, the Internet, and connections to game theory

Termite eusociality

Termites are eusocial by possessing two subfertile or sterile castes, the worker and the soldier. The consensus is that eusociality in termites is the result of a suite of factors (Thorne, 1997), though the relative importance accorded to each in the literature has shifted over time (Howard and Thorne, 2011). For the purpose of a quick review, I have not looked into mechanisms that appear … Continue reading Termite eusociality

Bad for birds, good for squirrels

Here’s a nice video I stumbled upon about Lisa Aubry’s group’s work at Utah State Uni. Climate change is having a positive effect on uinta ground squirrels, allowing them to fatten-up and attain weights higher than those recorded historically. This population is survival limited, and survival probability is higher the fatter the squirrels are, so abundance responds positively to this climate change. I can’t handle … Continue reading Bad for birds, good for squirrels