Experiments and simulations on short chain fatty acid production in a colonic bacterial community

Understanding how production of specific metabolites by gut microbes is modulated by interactions with surrounding species and by environmental nutrient availability is an important open challenge in microbiome research. As part of this endeavor, we explore interactions between F. prausnitzii, a major butyrate producer, and B. thetaiotaomicron, an acetate producer, under three different in vitro media conditions in monoculture and coculture. In silico Genome-scale dynamic flux balance analysis (dFBA) models of metabolism in the system using COMETS (Computation of Microbial Ecosystems in Time and Space) are also tested for explanatory, predictive and inferential power. Experimental findings indicate enhancement of butyrate production in coculture relative to F. prausnitzii monoculture but defy a simple model of monotonic increases in butyrate production as a function of acetate availability in the medium. Simulations recapitulate biomass production curves for monocultures and accurately predict the growth curve of coculture total biomass, using parameters learned from monocultures, suggesting that the model captures some aspects of how the two bacteria interact. However, a comparison of data and simulations for environmental acetate and butyrate changes suggest that the organisms adopt one of many possible metabolic strategies equivalent in terms of growth efficiency. Furthermore, the model seems not to capture subsequent shifts in metabolic activities observed experimentally under low-nutrient regimes. Some discrepancies can be explained by the multiplicity of possible fermentative states for F. prausnitzii. In general, these results provide valuable guidelines for design of future experiments aimed at better determining the mechanisms leading to enhanced butyrate in this ecosystem.https://www.biorxiv.org/content/10.1101/444760v1https://www.biorxiv.org/content/10.1101/444760v1Othe

La doctrina del efecto desaliento como punto de conexión entre el Derecho penal y los derechos fundamentales

ABSTRACT. A criminal norm may discourage the exercise of a fundamental right when it is disproportionately applied to conduct bordering on the legitimate exercise of that right. The purpose of this paper is to analyse this effect that criminal norms can produce, known as "chilling effect", taking as an example the events that occurred on 20 September 2017 before the Ministry of Economy of the Catalan Government

Transport engineering and reduction in crime: the Medellín case

[EN] This study analyses the impact of the aerial cable car public transport system, locally known as Metrocable, in Medellín (Colombia), on the reduction in crime. As part of the municipal policies of social urbanism, Metrocable has contributed to the social integration of the population in the outlying neighbourhoods, which has increased safety in Medellín. This case is clearly of great interest from the point of view of Criminal Sciences, demonstrating how crime can be combated by using tools beyond ius puniendi.Colomer Bea, D. (2016). Transport engineering and reduction in crime: the Medellín case. En XII Congreso de ingeniería del transporte. 7, 8 y 9 de Junio, Valencia (España). Editorial Universitat Politècnica de València. 1795-1801. https://doi.org/10.4995/CIT2016.2015.3434OCS1795180