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The situation that you presented in which an entity A inhibits the production of another entity B which in turn inhibits A, is a positive feedback. In a network path or a loop the overall sign of the loop/path is the product of the signs of individual edges (interactions). In this case it is negative times negative which gives a positive sign to the loop. ...


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Considering your assumption: I'm just looking at the exponential part, where the simple exponential equation works. If we assume there's sufficient nutrients for bacteria to grow unchecked for a number of hours (more-or-less true in a real culture) In your original model you are using discrete states and fixed time steps. So, if 30 min is one ...


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There are three seminal works that will give you an excellent grounding in the study of dynamical systems in population biology. The first details the foundations of population genetics: Crow, James F., and Motoo Kimura. An introduction to population genetics theory. (1970). The second deals with population ecology: Maynard-Smith, John. Models in ...


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There is no standard notation called Q (matrix). However in this case I think the matrix that they are referring to is the state transition matrix (similar to the adjacency matrix as mentioned by Justas in the comments, but with rates instead of just the connections). Basically you have three states (lets call them A, B and C) and there is a rate for ...


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Largely an informed guess based on properties of distributions rather than specific knowledge of statistical genetics: a beta distribution is useful for modeling the frequencies of two alleles at one locus. A Dirichelet distribution, which is a multivariate generalization of a beta distribution, would thus be useful for modeling a set of loci. The flip side ...


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Real bacteria population will likely reach some carrying capacity that will prevent them to grow exponentially. As a consequence, the exponential model will be a good fit for early growth only but after a while, one will need to use some other model (typically a logistic model). Logistic model Here, I quickly present one standard model of logistic growth ...


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If you are looking for a hard and fast answer, there is none. Life does not have a hard and fast definition, so it is impossible to identify something that everyone will recognize as both living and non-cellular. However, your question is answerable if you are interested in a summary of the state of the debate. All living organisms are made up of one ...


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I know of an example in development biology. Here is an example where noise in retinoic acid gradients is required for the boundaries in the developing hindbrain to sharpen. A related result is that the zebrafish hindbrain has a protein to modulate noise, but does not reduce the noise to zero. Together these results show that noise in the retinoic acid ...



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