En defensa de la poesia: pàgina web

La poesia és un genère literari que es veu sotmès a una paradoxa: per un costat, és ben valorat ocialment, ja que es considera que només la poden escriure uns "escollits" i també la poden llegir només els "iniciats". Però aquesta concepció genera una actitud en contra del mateix gènere: que ls que no es consideren "escollits" ni "iniciats" fàcilment se n'allunyen, de vegades de forma definitiva. Alguns del tòpics que des de sempre acompanyen la poesia poden ajudar a entendre questa actitud

Fronts from complex two-dimensional dispersal kernels: theory and application to Reid's paradox

Bimodal dispersal probability distributions with characteristic distances differing by several orders of magnitude have been derived and favorably compared to observations by Nathan [Nature (London) 418, 409 (2002)]. For such bimodal kernels, we show that two-dimensional molecular dynamics computer simulations are unable to yield accurate front speeds. Analytically, the usual continuous-space random walks (CSRWs) are applied to two dimensions. We also introduce discrete-space random walks and use them to check the CSRW results (because of the inefficiency of the numerical simulations). The physical results reported are shown to predict front speeds high enough to possibly explain Reid's paradox of rapid tree migration. We also show that, for a time-ordered evolution equation, fronts are always slower in two dimensions than in one dimension and that this difference is important both for unimodal and for bimodal kernels