1,721,083 research outputs found
2500 years ago scientific theories of the origin of life arose in ancient Greece
No full textWhat have the Greeks ever done for us? Everything. This short commentary celebrating the earliest history of origin of life research seeks to bring to the attention of the community of origin of life researchers that there is a much longer tradition of scientific theories in this subject than some people are aware of; there are 2500 years of thinking that we should not forget about. In Ionian Greece, Thales initiated ideas that we can see as the beginnings of science itself. Anaximander, his pupil, was particularly interested in the origins of the world, including how life had arisen, and proposed a species of proto-evolutionary theory of the origin of life. 2500 years ago, Anaxagoras left Ionia for Athens taking ideas of scientific thinking with him. Anaxagoras is credited with being the originator of a further theory of the origin of life, that of panspermia. The scientific conception of knowledge was attacked almost immediately, and Anaxagoras ended up exiled, but that idea of the knowability of things survived and led, many centuries later, to the scientific revolution and to our current human civilization.Peer reviewe
DNA as information: At the crossroads between biology, mathematics, physics and chemistry
Get PDFOn the one hand, biology, chemistry and also physics tell us how the process of translating the genetic information into life could possibly work, but we are still very far from a complete understanding of this process. On the other hand, mathematics and statistics give us methods to describe such natural systems-or parts of them-within a theoretical framework. Also, they provide us with hints and predictions that can be tested at the experimental level. Furthermore, there are peculiar aspects of the management of genetic information that are intimately related to information theory and communication theory. This theme issue is aimed at fostering the discussion on the problem of genetic coding and information through the presentation of different innovative points of view. The aim of the editors is to stimulate discussions and scientific exchange that will lead to new research on why and how life can exist from the point of view of the coding and decoding of genetic information. The present introduction represents the point of view of the editors on the main aspects that could be the subject of future scientific debate
De tessere quinquangula: five hundred years of pentagonal tilings from Dürer to Mackay via Kepler, Escher, and Penrose
No full textAlbrecht Dürer began the mathematical study of pentagonal tilings five hundred years ago with the publication in 1525 of his textbook of mathematics Underweysung der Messung. A century later Johannes Kepler produced more elaborate and intricate pentagonal tilings. In the 20th century Maurits Escher made pentagonal tilings into art. Escher’s art–science interactions with Roger Penrose made the latter keep thinking about tilings; he made pentagonal tilings tile the plane aperiodically in 1974. And Alan Mackay built on and extended Penrose’s work to predict the existence of quasicrystals in 1981.Peer reviewe
Dynamics of the osmotic lysis of mineral protocells and its avoidance at the origins of life
No full texthe osmotic rupture of a cell, its osmotic lysis or cytolysis, is a phenomenon that active biological cell volume regulation mechanisms have evolved in the cell membrane to avoid. How then, at the origin of life, did the first protocells survive prior to such active processes? The pores of alkaline hydrothermal vents in the oceans form natural nanoreactors in which osmosis across a mineral membrane plays a fundamental role. Here, we discuss the dynamics of lysis and its avoidance in an abiotic system without any active mechanisms, reliant upon self-organized behaviour, similar to the first self-organized mineral membranes within which complex chemistry may have begun to evolve into metabolism. We show that such mineral nanoreactors could function as protocells without exploding because their self-organized dynamics have a large regime in parameter space where osmotic lysis does not occur and homeostasis is possible. The beginnings of Darwinian evolution in proto-biochemistry must have involved the survival of protocells that remained within such a safe regime.We acknowledge the financial support of the Spanish FEDER/Junta de Andalucía- Consejería de Economía y Conocimiento project PY2001389 and the contribution of the COST Action CA21169, Dynalife, supported by European Cooperation in Science and Technology.Peer reviewe
Diffusion-controlled growth of a planar chemical garden wall before osmotic fracture
No full textChemical gardens refer to a class of self-assembling structures of semi-permeable precipitates. They have been attracting significant interest due to their relevance to sub-oceanic hydrothermal vents and the origin of life. We have investigated the growth behaviour of chemical garden walls in a horizontal Hele-Shaw cell. The experiments were conducted with pellets of either solid cobalt(II) or manganese(II) chloride contained in aqueous sodium silicate solutions. It is found that the growth of the chemical garden walls can be well described by a simple, diffusion-controlled dynamical model until their eventual osmotic fracture at a reproducible time. This provides a basis by which wall growth in more complex chemical garden systems can be characterized. This article is part of the theme issue 'Biological fluid dynamics: emerging directions'.The authors acknowledge the financial support from the European Cooperation in Science and Technology Action CA21169 Dynalife.Peer reviewe
Effect of diversity distribution symmetry on global oscillations of networks of excitable units
No full textWe show that the degree of symmetry of the diversity distribution is the key determinant of global oscillations in coupled networks of FitzHugh-Nagumo units, used as prototypical examples of excitable systems. In these ensembles, symmetric diversity reliably yields resonant collective oscillations - even when all units are individually excitable - whereas asymmetric diversity suppresses them. Two symmetry-based metrics predict the presence or absence of global oscillations from the distribution alone. A simple mean-field mechanism, corroborated by a minimal two-unit analysis, explains how symmetry creates a landscape that supports limit cycles. These results identify diversity distribution symmetry as a key mechanism for emergent synchronization in excitable media.S.S., M.P., and E.H. acknowledge support from the Estonian Research Council through Grant No. PRG1059. M.E.Y. acknowledges support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) via Grant No. YA 764/1-1, Project No. 456989199. J.H.E.C. acknowledges support from the Spanish Ministerio de Ciencia, Innovación y Universidades through Grant No. PID2024-160443NB-I00.Peer reviewe
Dynamical equivalence between resonant translocation of a polymer chain and diversity-induced resonance
No full textNetworks of heterogeneous oscillators are often seen to display collective synchronized oscillations, even when single elements of the network do not oscillate in isolation. It has been found that it is the diversity of the individual elements that drives the phenomenon, possibly leading to the appearance of a resonance in the response. Here, we study the way in which heterogeneity acts in producing an oscillatory regime in a network and show that the resonance response is based on the same physics underlying the resonant translocation regime observed in models of polymer diffusion on a substrate potential. Such a mechanical analog provides an alternative viewpoint that is useful to interpret and understand the nature of collective oscillations in heterogeneous networks.M.P., E.H., and S.S. acknowledge support from the Estonian Research Council through Grant No. PRG1059. M.E.Y. acknowledges support from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) via Project No. 456989199.Peer reviewe
Competing structures in a minimal double-well-potential model of condensed matter
No full textThe microscopic structure of several amorphous substances often reveals complex patterns such as medium- or long-range order, spatial heterogeneity, and even local polycrystallinity. To capture all these features, models usually incorporate a refined description of the particle interaction that includes an ad hoc design of the inside of the system constituents and use temperature as a control parameter. We show that all these features can emerge from a minimal athermal two-dimensional model where particles interact isotropically by a double-well potential, which includes an excluded volume and a maximum coordination number. The rich variety of structural patterns shown by this simple geometrical model apply to a wide range of real systems including water, silicon, and different amorphous materials.B.E. acknowledges support from Grant Nos. PCIN-2017-098, PTA2020-018247-I, and PID2020-118974GB-C21 from the Spanish Ministerio de Ciencia e Innovación. J.H.E.C. and C. I. S. D. acknowledge support from the Spanish Ministerio de Ciencia, Innovación y Universidades through Grant No. PID2024-160443NB-I00. S.R.-V. acknowledges support from the European Commission through the Marie Skłodowska-Curie Individual Fellowship
840195-ARIADNE. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon Europe research and innovation program ERC-AdG-2022 (GA No. 101096293).Peer reviewe
Filament dynamics in planar chemical gardens
No full textFilaments in a planar chemical garden grow following tortuous, erratic paths. We show from statistical mechanics that this scaling results from a self-organized dispersion mechanism. Effective diffusivities as high as 10−5 m2 s−1 are measured in 2D laboratory experiments. This efficient transport is four orders of magnitude larger than molecular diffusion in a liquid, and ensures widespread contact and exchange between fluids in the chemical-garden structure and its surrounding environment.L. A. M. R. gratefully acknowledges funding from the Fundaçaio para a Ciencia e Tecnologia (FCT), Portugal (grant SFRH/BD/ 130401/2017). The authors acknowledge the contribution of the COST Action Chemobrionics, CA17120Peer reviewe
Experimental modelling of the growth of tubular ice brinicles from brine flows under sea ice
No full textThe supplementary material deposited in this dataset are movies at real time describing the crystal growth of ice brinicles in different experimental conditions simulating the natural forms found in Arctic and Antarctic oceans and other planets.European COST Action CA17120 supported by the EU Framework Programme Horizon 2020. S.T. acknowledges the CSIC and Spanish Andalusian ‘Garantía Juvenil’ project AND21_IACT_M2_058Peer reviewe
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