La influencia de la biología en la monadología de Leibniz

En este artículo se aborda la influencia de los estudios biológicos de origen y desarrollo de los seres vivos en la ontología de Leibniz, en concreto del mundo abierto por los microscopistas como Leeuwenhoek, Swammerdam o Malpighi. El preformacionismo animalculista leibniziano será su opción embriológica en el contexto de la preexistencia del alma y el cuerpo orgánico desde el origen del mundo. Lo individuos vivos serán la médula de su ontología en la etapa previa a su monadología madura, y lo seguirán siendo en forma de sustancias compuestas en sus últimos añosThis article deals with the influence of biological studies about the origin and development of living things on Leibniz’s ontology; in particular, the discoveries by microscopists such as Leeuwenhoek, Swammerdam and Malpighi. For Leibniz, Animalcular Preformationism will also be the option in the embriological field in the context of the soul’s pre-existence and the organic body’s pre-existence from the origin of the world. Living individuals will be at the heart of his ontology in the previous stage to mature Monadology and will continue to be in the form of composed substances in his last years

Spacetime from locality of interactions in deformations of special relativity: the example of κ\kappa-Poincar\'e Hopf algebra

A new proposal for the notion of spacetime in a relativistic generalization of special relativity based on a modification of the composition law of momenta is presented. Locality of interactions is the principle which defines the spacetime structure for a system of particles. The formulation based on $\kappa$-Poincar\'e Hopf algebra is shown to be contained in this framework as a particular example.Comment: 14 page

Observers and their notion of spacetime beyond special relativity

It is plausible that quantum gravity effects may lead us to a description of Nature beyond the framework of special relativity. In this case, either the relativity principle is broken or it is maintained. These two scenarios (a violation or a deformation of special relativity) are very different, both conceptually and phenomenologically. We discuss some of their implications on the description of events for different observers and the notion of spacetime.Comment: 10 page

Beyond Special Relativity at second order

The study of generic, non-linear, deformations of Special Relativity parametrized by a high-energy scale $M$, which was carried out at first order in $M$ in Phys.Rev. D86, 084032 (2012), is extended to second order. This can be done systematically through a ('generalized') change of variables from momentum variables that transform linearly. We discuss the different perspectives on the meaning of the change of variables, obtain the coefficients of modified composition laws and Lorentz transformations at second order, and work out how $\kappa$-Poincar\'e, the most commonly used example in the literature, is reproduced as a particular case of the generic framework exposed here.Comment: 19 page

Twin Peaks: A possible signal in the production of resonances beyond special relativity

It is usually expected that quantum gravity corrections will modify somehow the symmetries of special relativity. In this paper we point out that the possibility of very low-energy (with respect to the Planck energy) modifications to special relativity in the framework of a deformed relativistic theory is not ruled out, and that, depending on the value of that scale, such a possibility could be tested in accelerator physics. In particular, we take a simple example of a relativistic kinematics beyond special relativity from the literature, and obtain a remarkable effect: two correlated peaks ("twin peaks") associated to a single resonance. We analyze this phenomenology in detail, use LEP data to put constraints of the order of TeV on the scale of corrections to special relativity, and note that such an effect might be observable in a future very high-energy proton collider.Comment: 17 pages, accepted for publication in Symmetr

Geometry of multiparticle systems with a relativistic deformed kinematics and the relative locality principle

There is a vast literature showing the connection between a deformed relativistic kinematics and a curved momentum space and, in particular, how the former can be obtained from the geometrical properties of the latter. However, there is not any mention about the geometry of a multiparticle system making manifest a possible modification in the metric of one particle due to the presence of others. In this work, we explore how a curved momentum metric depending on the particles involved in an interaction arises when considering a process. We also show that the principle of relative locality obtained in doubly special relativity from an action is achieved in this geometrical framework in a direct fashion. Moreover, this formalism allows us to generalize this principle when a curvature of spacetime is present in a natural way. Furthermore this geometrical setup allows us to define a new momentum dependent space-time coordinates for a multiparticle system in which locality of interactions is recovered. © 2021 American Physical Society

Study of the Prevalence of Metabolic Syndrome in Pediatric Obesity Patients

Treballs Finals de Grau de Nutrició Humana i Dietètica, Facultat de Farmàcia i Ciències de l'Alimentació, Campus de l'Alimentació de Torribera, Universitat de Barcelona. Curs: 2024-2025. Tutor: Augusto Miguel Anguita Ruiz[eng] Objective: The aim of this study was to evaluate the prevalence of Metabolic Syndrome (MetS) in Spanish children from three different cohorts, according to the definition by Ahrens et al. (2014) (IDEFICS study, action level). Additionally, it analyzed the components of MetS in each cohort to evaluate their impact on MetS prevalence across pediatric populations. Study design: The study comprised 2,411 participants aged between 3 and 18 years from three Spanish cities: Santiago de Compostela (N = 1,497), Zaragoza (N = 396), and Córdoba (N = 518). In all cohorts, recruited from hospital settings, anthropometric and biochemical data were collected and analyzed to determine the prevalence of MetS and to compare among cohorts. Results: MetS prevalence was notably high in children with obesity across all cohorts (Córdoba: 91.3%; Santiago de Compostela: 92.7%; Zaragoza: 86.8%). Additionally, MetS prevalence increased with pubertal development, rising from 11.3% in prepubertal children to 37.5% in pubertal children in the Córdoba cohort. The same trend was observed in the Santiago and Zaragoza cohorts. Regarding socioeconomic status, Córdoba had the highest proportion of families with low parental education (45.0%) compared to Santiago (11.6%) and Zaragoza (5.8%). Conclusion: In conclusion, significant regional, pubertal, and socioeconomic differences highlight the influence of biological and contextual factors on metabolic risk, emphasizing the urgent need to develop unified consensus guidelines for pediatric MetS.[cat] Objectiu: L'objectiu d'aquest estudi va ser avaluar la prevalença de Síndrome Metabòlica (MetS) en nens espanyols de tres cohorts diferents, d'acord amb la definició d'Ahrens et al. (2014) (IDEFICS study, action level). A més, es van analitzar els components de la MetS de cada cohort per avaluar el seu impacte en la prevalença de la MetS en poblacions pediàtriques. Disseny de l'estudi: L'estudi va incloure 2.411 participants d'entre 3 i 18 anys, de tres ciutats espanyoles: Santiago de Compostela (N = 1.497), Saragossa (N = 396), i Còrdova (N = 518). A totes les cohorts, reclutades a entorns hospitalaris, es van recollir i analitzar dades antropomètriques i bioquímiques per a determinar la prevalença de MetS i comparar entre les cohorts. Resultats: La prevalença de MetS va ser notablement alta en nens amb obesitat a totes les cohorts (Còrdova 91,3%; Santiago: 92,7%; Saragossa: 86,8%). Tanmateix, la prevalença de MetS va augmentar amb el desenvolupament puberal, passant de l'11,3% en nens prepuberals al 37,5% en nens puberals a la cohort de Còrdova. Es va observar la mateixa tendència en les cohorts de Santiago i Saragossa. Pel que fa al nivell socioeconòmic, Còrdova va presentar la proporció més alta de famílies amb un nivell educatiu parental baix (45,0%) en comparació amb Santiago (11,6%) i Saragossa (5,8%). Conclusió: En conclusió, les diferències regionals, puberals i socioeconòmiques posen de manifest la influència de factors biològics i de l'entorn en el risc metabòlic, destacant la urgent necessitat de desenvolupar guies consensuades i unificades per a la MetS pediàtrica

Relativistic deformed kinematics from locality conditions in a generalized spacetime

We show how a deformed composition law of four-momenta can be used to define, at the classical level, a modified notion of spacetime for a system of two particles through the crossing of worldlines in particle interactions. We present a derivation of a generic relativistic isotropic deformed kinematics and discuss the complementarity and relations with other derivations based on kappa-Poincare Hopf algebra or on the geometry of a maximally symmetric momentum space

Exploring black hole mechanics in cotangent bundle geometries

The classical and continuum limit of a quantum gravitational setting could lead, at mesoscopic regimes, to a very different notion of geometry with respect to the pseudo-Riemannian one of special and general relativity. A possible way to characterize this modified spacetime notion is by a momentum-dependent metric, in such a way that particles with different energies could probe different spacetimes. Indeed, doubly special relativity theories, deforming the special relativistic kinematics while maintaining a relativity principle, have been understood within a geometrical context, by considering a curved momentum space. The extension of these momentum spaces to curved spacetimes and its possible phenomenological implications have been recently investigated. Following this line of research, we address here the first two laws of black holes thermodynamics in the context of a cotangent bundle metric, depending on both momentum and spacetime coordinates, compatible with the relativistic deformed kinematics of doubly special relativity