we find a criterion for a morphism of coalgebras over a barr-exact category to be effective descent and determine (effective) descent morphisms for coalgebras over toposes in some cases. also, we study some exactness properties of endofunctors of arbitrary categories in connection with natural transformations between them as well as those of functors that these transformations induce between co...

While most molecular biologists are familiar with the artificial transformation of bacteria in the context of laboratory cloning experiments, natural competence for transformation refers to a specific physiological state in which prokaryotes are able to take up genetic material from their surroundings. Occasionally, such absorbed DNA is recombined into the organism's own genome, resulting in na...