Wood mouse feeding effort and decision-making when encountering a restricted unknown food source

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Animals making foraging decisions must balance the energy gained, the time invested, and the influence of key environmental factors. In our work, we examined the effect of predation risk cues and experience on feeding efforts when a novel food resource was made available. To achieve this, we live-trapped wood mouse Apodemus sylvaticus in Monte de Valdelatas (Madrid), where 80 Sherman traps were set in four plots. Traps were subjected to two food-access difficulties in treatments consisting of three consecutive nights: open plastic bottles (easy) and closed bottles (difficult), both using corn as bait. To simulate predation risk, we set fox faeces in half of the traps in each plot. We also considered moonlight (medium/low) as an indirect predation risk cue. We analysed whether bottles had been bitten by mice and the gnawed area of each bottle was measured. Our results indicated that food access difficulty, experience, and predation risk determined mice feeding decisions and efforts. The ability of mice to adapt feeding effort when a new food source is available was demonstrated because a higher proportion of closed bottles exhibited bite marks and the gnawed area was bigger. Moreover, mouse experience was determinant in the use of this new resource since recaptured mice gnawed broader orifices in the bottles and the gnawed area increased each time an individual was recaptured. Additionally, direct predation risk cues prompted mice to bite the bottles whereas the effect of different moon phases varied among the food access treatments. This study provides direct evidence of formidable efficacy of wild mice to exploit a new nutrient resource while considering crucial environmental factors that shape the decision-making procedur

Majorana vs Pseudo-Dirac Neutrinos at the ILC

Neutrino masses could originate in seesaw models testable at colliders, with light mediators and an approximate lepton number symmetry. The minimal model of this type contains two quasi-degenerate Majorana fermions forming a pseudo-Dirac pair. An important question is to what extent future colliders will have sensitivity to the splitting between the Majorana components, since this quantity signals the breaking of lepton number and is connected to the light neutrino masses. We consider the production of these neutral heavy leptons at the ILC, where their displaced decays provide a golden signal: a forward-backward charge asymmetry, which depends crucially on the mass splitting between the two Majorana components. We show that this observable can constrain the mass splitting to values much lower than current bounds from neutrinoless double beta decay and natural loop corrections.Comment: 16 pages, 5 figures; v2: Minor changes, version accepted for publication in EPJ

Ressenyes

Obra ressenyada: José Manuel NAREDO, La economía en evolución. Madrid: Siglo XXI, 2003

Ressenyes

Obra ressenyada: Juan Carlos DOMÍNGUEZ NAFRÍA, El Real y Supremo Consejo de Guerra (siglos XVI-XVIII). Madrid: Centro de Estudios Políticos y Constitucionales, 2001

Theoretical and experimental approaches for the initiation and propagation of activity in spatially embedded neuronal cultures

[eng] Spatial embedding and inherited metric constraints are a fundamental trait of biological neuronal circuits. However their role in shaping connectivity and dynamics has been often disregarded, with models of neuronal networks paying much more attention to the distribution of connections in the quest for understanding network's behavior. In this thesis we aim at filling this gap by studying the importance of metric features in the complex connectivity- dynamics-noise interplay that shapes spontaneous neuronal activity. This thesis combines experiments in rat dissociated neuronal cultures with theoretical analyses to better comprehend the relevance of spatial embedding. We developed a new theoretical model grounded on Ising Models to assess metric effects in neuronal cultures' behavior, and in the context of percolation approaches. Once metric effects were settled, we illustrated their relevance in shaping spontaneous activity by perturbing the structural connectivity blueprint of neuronal cultures. This was achieved by patterning the substrate where neurons grow, and by using topographical molds that dictated the connectivity of the network. Next, and since the initiation of bursting activity is governed in great manner by a complex amplification mechanism that involves metric correlations and noise, we focused on the metric-driven amplification of spontaneous single-neuron noise to derive an analytical model that predicts the frequency of bursting events in neuronal cultures. We then further investigated in an experimental context the contribution of noise to the observed activity patterns, and by implementing a moderate electrical stimulation protocol that increases the level of activity noise in cultures. Finally, the latter study was completed with experiments regarding the specific role of inhibition in neuronal networks, to provide a wider understanding of the mechanisms that govern the initiation and propagation of activity fronts in cortical cultures.[cat] L'objectiu d'aquesta tesis és investigar els mecanismes que generen l'activitat espontània i estimulada en xarxes neuronals, més concretament en cultius corticals dissociats, i fent un especial èmfasi en l’efecte de les correlacions mètriques. En aquest marc, l’activitat col·lectiva consisteix en episodis esporàdics de dispars quasi sincronitzats entre totes les neurones del cultiu, anomenats “esclats de xarxa”. Tres elements principals en determinen les característiques: connectivitat entre neurones, dinàmica intrínseca neuronal, i soroll (activacions neuronals aleatòries). La investigació s’ha centrat en cinc línies de recerca: l’estudi de correlacions mètriques en cultius neuronals; el desenvolupament d’un model teòric per descriure i predir l’esclat de xarxa; l’anàlisi de la propagació dels fronts d’activitat experimentals sota pertorbacions estructurals de la connectivitat del cultiu; l’estudi de l’efecte de la inhibició en la iniciació i propagació dels esclats ‘in vitro’; i l’estudi de la resposta experimental dels cultius sota una estimulació elèctrica moderada de baixa freqüència. En la primera línia de recerca hem comprovat que les correlacions mètriques dominen el comportament dinàmic del cultiu, fins al punt d’emmascarar la contribució de la distribució del nombre de connexions. En la segona línia hem desenvolupat un model analític que prediu semi- quantitativament la freqüència dels esclats observada experimentalment. La tercera línia s’ha centrat en l’efecte de pertorbacions estructurals en la connectivitat; la dinàmica resultant ha mostrat una gran riquesa en patrons d’activitat, esclats de xarxa a diferents escales, i propagació altament específica de cada cultiu. La quarta línia de recerca ha demostrat que les xarxes sense inhibició disminueixen la seva freqüència d’esclat respecte a les xarxes control, que la velocitat de propagació de l’activitat incrementa lleugerament quan s’ha bloquejat la inhibició, i que els punts on s’inicien ens esclats varien respecte als controls. I, finalment, la cinquena línia de recerca ha constatat que l’aplicació d’un camp elèctric feble augmenta el soroll d’activitat de la xarxa, generant un increment en la freqüència dels esclats de xarxa

Ancient Cartographies as a Basis for Geolocation Models in Public Space: The Case of Giambattista Nolli and its Heritage Application

In 1748, the architect and surveyor Giambattista Nolli mapped an abstract reality of the city of Rome. As a challenge to the inherited projections, it represented the city mixing streets, halls, corridors, churches, baths and markets as part of a unique public space network. A new way to design public space and rethink the whole urban system was opened by the possibility of containing in these representations a single layer with all kinds of public space (including the interior of public buildings). Despite this, Nolli's plan remained as a useless instrument since the hegemony of automobile mobility appeared as a pre-eminent system. This research tries to understand how the application of the ancient cartographies' methodology can improve the pedestrian mobility of historic cities by means of enhancing the graphic value of the system of Giambattista Nolli. Nowadays, free public space is represented as empty and built ones, as solid. This proposal would revert this reified conception of the city, understanding this baroque representation as an instrument of identification and assessment of the transitional heritage. The clues unveiled by Nolli seem to be able to integrate the plans of public buildings within the urban tissue, which would result in a step towards the full integration of cartography and mobility. The success of the comprehensive tools offered by large servers such as Alphabet inc. (Google) or Bing Maps confirm the suitability of the combination of new technologies and Big Data with urban planning, reaching the synchronisation of Smart Cities. Nowadays, open public space can be 'walked in' from any electronic device, consequently, the application of the "Nolli methodology" would implement the model of urban geolocation with the assimilation of inner public spaces. In the creation of a great global map of the public space, a chimaera could be intuited. This would be discussed within a tangible reality: every open public space is already housed in the Big Data and it is accessible through geolocation tools. The inclusion of the of the public buildings' interiors would contribute to develop a greater permeability between city and citizens. Furthermore, this representation would optimize pedestrian travel times and would be able to expand the geolocation system network as a documentary repository

Estudi del procés de mineralització en el sòl compost de deixalles

Per tal de conèixer i poder explicar tots els processos que segueixen les diferents formes nitrogenades d'un sòl en el qual s'ha barrejat compost de residus sòlids urbans, es fan servir dos mètodes diferents: I- Incubació de les barreges sota condicions controlades, registrant l'activitat microbiana mitjançant una respirometria i analizant periòdicament el nivell de N-NH4+, N-NO3-. N.org. sol., N org. total i de C ox. sol. que hi ha a la barreja. II- Assaig de conreu de margall en tests, prenent mensualment mostres de substrat, del qual s'analitza el mateix que a les incubacions, i mostres de teixits vegetals, dels quals es determina la producció total i la riquesa en nitrogen. La mineralització del nitrogen i la producció vegetal als tractaments adobats amb compost presenten un retard considerable respecte als controls més com més alta és l'activitat dels microorganismes. Aquest retard s'atribueix a la immobilització microbiana.To know amd to explain the processes followed by the different nitrogenate forms of a soil where compost of City garbage has been added, two methods are used: I- Incubation of the mixture under controllate conditions, studying the microbial activity with respirometry and periodically analysing the level of N-NO3-, water soluble organic N, total organic N and oxidable water soluble carbon of the mixture. II- Growing test of ray grass in pots, taking soil and vegetable samples monthly doing the same analysis than in the incubation for the soil and controlling total dry production and nitrogen content for the ray grass. The high doses of compost used and its low stability initially produce nitrogen immobilization in the incubation as well as in the growing tests.Para conocer y poder explicar todos los procesos que siguen las diferentes formas nitrogenadas de un suelo al que se le ha mezclado compost de residus urbanos, se utilizan dos métodos diferentes: I- Incubación de la mezcla bajo condiciones controladas, registrando la actividad microbiana mediante una respirometria y analizando periódicamente el nivel de N-NH4 +, N-NO3-, N org. sol., N org. total y de C ox. sol. que hay en la mezcla. II- Ensayo de cultivo de ray-gras en macetas, tomando mensualmente muestras de sustrato, del que se analiza lo mismo que en las incubaciones, y muestras de tejido vegetal, del que se determina la producción total y la riqueza en nitrógeno. La mineralización del nitrógeno y la producción vegetal en los tratamientos abonados con compost presentan un retraso considerable respecto al control, mayor cuanto mayor es la actividad de los microorganismos. Este retraso se atribuye a la inmovilización microbiana

Timespace for Emotions: Anachronism in Flaubert, Bal/Williams Gamaker, Munch and Knausgård

Quoting Flaubert through time, Mieke Bal and Michelle Williams Gamaker’s Madame B brings Madame Bovary’s reflections on love and emotions to the present day, in a productive anachronism. Their work produces an intertemporal space where the past is relevant for the present, and the present enables us to understand the past. Intimacy and routine are central in their exploration of Flaubert’s contemporaneity. Those issues are precisely one of the keys in Karl Ove Knausgård’s project of literary autobiography, where he expands narration foreclosing the ellipsis and giving visibility to small things and emotions; a project with some resonances with Munch’s crude-obscene uses of intimacy. This essay explores how both proposals, Bal and Williams Gamaker in film, and Knausgård in literature, can serve us to connect present and past sensibilities and, more than that, demonstrate resistances to the hegemonic discourses of temporality