1,347 research outputs found
A multiobjective optimization approach to statistical mechanics
Optimization problems have been the subject of statistical physics
approximations. A specially relevant and general scenario is provided by
optimization methods considering tradeoffs between cost and efficiency, where
optimal solutions involve a compromise between both. The theory of Pareto (or
multi objective) optimization provides a general framework to explore these
problems and find the space of possible solutions compatible with the
underlying tradeoffs, known as the {\em Pareto front}. Conflicts between
constraints can lead to complex landscapes of Pareto optimal solutions with
interesting implications in economy, engineering, or evolutionary biology.
Despite their disparate nature, here we show how the structure of the Pareto
front uncovers profound universal features that can be understood in the
context of thermodynamics. In particular, our study reveals that different
fronts are connected to different classes of phase transitions, which we can
define robustly, along with critical points and thermodynamic potentials. These
equivalences are illustrated with classic thermodynamic examples.Comment: 14 pages, 8 figure
In silico transitions to multicellularity
The emergence of multicellularity and developmental programs are among the
major problems of evolutionary biology. Traditionally, research in this area
has been based on the combination of data analysis and experimental work on one
hand and theoretical approximations on the other. A third possibility is
provided by computer simulation models, which allow to both simulate reality
and explore alternative possibilities. These in silico models offer a powerful
window to the possible and the actual by means of modeling how virtual cells
and groups of cells can evolve complex interactions beyond a set of isolated
entities. Here we present several examples of such models, each one
illustrating the potential for artificial modeling of the transition to
multicellularity.Comment: 21 pages, 10 figures. Book chapter of Evolutionary transitions to
multicellular life (Springer
Synthetic Turing protocells: vesicle self-reproduction through symmetry-breaking instabilities
The reproduction of a living cell requires a repeatable set of chemical
events to be properly coordinated. Such events define a replication cycle,
coupling the growth and shape change of the cell membrane with internal
metabolic reactions. Although the logic of such process is determined by
potentially simple physico-chemical laws, the modeling of a full,
self-maintained cell cycle is not trivial. Here we present a novel approach to
the problem which makes use of so called symmetry breaking instabilities as the
engine of cell growth and division. It is shown that the process occurs as a
consequence of the breaking of spatial symmetry and provides a reliable
mechanism of vesicle growth and reproduction. Our model opens the possibility
of a synthetic protocell lacking information but displaying self-reproduction
under a very simple set of chemical reactions
La pandemia de gripe: una amenaza global
Pocos virus se han cobrado en el pasado un número tan alto de víctimas como la gripe. La posibilidad de una nueva pandemia ha generado una alerta más que justificada tanto a nivel social como en términos de su posible impacto en las economías de todo el mundo.
La Organización Mundial de la Salud ha señalado que sólo 40 países del mundo han desarrollado planes de prevención contra la pandemia de gripe. Sin embargo, la gripe de 1918 y otras pandemias fueron efectivas en gran medida debido a la falta de previsión. Esta situación puede evitarse en esta ocasión, y una parte importante de lo efectiva que sea la lucha contra la pandemia surgirá de una información eficiente y coordinada durante las fases iniciales. No menos importante es ser conscientes del carácter global del fenómeno y que por lo tanto hay que mirar algo más allá de lo puramente doméstico
Minimal model of self-replicating nanocells: a physically embodied information-free scenario
The building of minimal self-reproducing systems with a physical embodiment
(generically called protocells) is a great challenge, with implications for
both theory and applied sciences. Although the classical view of a living
protocell assumes that it includes information-carrying molecules as an
essential ingredient, a dividing cell-like structure can be built from a
metabolism-container coupled system, only. An example of such a system, modeled
with dissipative particle dynamics, is presented here. This article
demonstrates how a simple coupling between a precursor molecule and surfactant
molecules forming micelles can experience a growth-division cycle in a
predictable manner, and analyzes the influence of crucial parameters on this
replication cycle. Implications of these results for origins of cellular life
and living technology are outlined.Comment: 9 pages, 10 figure
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