114 research outputs found

    Modelling Ordinal Responses with Uncertainty: a Hierarchical Marginal Model with Latent Uncertainty components

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    In responding to rating questions, an individual may give answers either according to his/her knowledge/awareness or to his/her level of indecision/uncertainty, typically driven by a response style. As ignoring this dual behaviour may lead to misleading results, we define a multivariate model for ordinal rating responses, by introducing, for every item, a binary latent variable that discriminates aware from uncertain responses. Some independence assumptions among latent and observable variables characterize the uncertain behaviour and make the model easier to interpret. Uncertain responses are modelled by specifying probability distributions that can depict different response styles characterizing the uncertain raters. A marginal parametrization allows a simple and direct interpretation of the parameters in terms of association among aware responses and their dependence on explanatory factors. The effectiveness of the proposed model is attested through an application to real data and supported by a Monte Carlo study

    A non local model for cell migration in response to mechanical stimuli

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    Cell migration is one of the most studied phenomena in biology since it plays a fundamental role in many physiological and pathological processes such as morphogenesis, wound healing and tumorigenesis. In recent years, researchers have performed experiments showing that cells can migrate in response to mechanical stimuli of the substrate they adhere to. Motion toward regions of the substrate with higher stiffness is called durotaxis, while motion guided by the stress or the deformation of the substrate itself is called tensotaxis. Unlike chemotaxis (i.e. the motion in response to a chemical stimulus), these migratory processes are not yet fully understood from a biological point of view. In this respect, we present a mathematical model of single-cell migration in response to mechanical stimuli, in order to simulate these two processes. Specifically, the cell moves by changing its direction of polarization and its motility according to material properties of the substrate (e.g., stiffness) or in response to proper scalar measures of the substrate strain or stress. The equations of motion of the cell are non-local integro-differential equations, with the addition of a stochastic term to account for random Brownian motion. The mechanical stimulus to be integrated in the equations of motion is defined according to experimental measurements found in literature, in the case of durotaxis. Conversely, in the case of tensotaxis, substrate strain and stress are given by the solution of the mechanical problem, assuming that the extracellular matrix behaves as a hyperelastic Yeoh's solid. In both cases, the proposed model is validated through numerical simulations that qualitatively reproduce different experimental scenarios

    Exploring the Italian equine gene pool via high-throughput genotyping

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    Introduction: The Italian peninsula is in the center of the Mediterranean area, and historically it has been a hub for numerous human populations, cultures, and also animal species that enriched the hosted biodiversity. Horses are no exception to this phenomenon, with the peculiarity that the gene pool has been impacted by warfare and subsequent “colonization”. In this study, using a comprehensive dataset for almost the entire Italian equine population, in addition to the most influential cosmopolitan breeds, we describe the current status of the modern Italian gene pool.Materials and Methods: The Italian dataset comprised 1,308 individuals and 22 breeds genotyped at a 70 k density that was merged with publicly available data to facilitate comparison with the global equine diversity. After quality control and supervised subsampling to ensure consistency among breeds, the merged dataset with the global equine diversity contained data for 1,333 individuals from 54 populations. Multidimensional scaling, admixture, gene flow, and effective population size were analyzed.Results and Discussion: The results show that some of the native Italian breeds preserve distinct gene pools, potentially because of adaptation to the different geographical contexts of the peninsula. Nevertheless, the comparison with international breeds highlights the presence of strong gene flow from renowned breeds into several Italian breeds, probably due to historical introgression. Coldblood breeds with stronger genetic identity were indeed well differentiated from warmblood breeds, which are highly admixed. Other breeds showed further peculiarities due to their breeding history. Finally, we observed some breeds that exist more on cultural, traditional, and geographical point of view than due to actual genetic distinctiveness

    The spacetime associated with galactic dark matter halos

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    We show how an adequate post--Newtonian generalization can be obtained for Newtonian dark matter halos associated with an empiric density profile. Applying this approach to halos that follow from the well known numerical simulations of Navarro, Frenk and White (NFW), we derive all dynamical variables and show that NFW halos approximatelly follow an ideal gas type of equation of state which fits very well to a polytropic relation in the region outside the core. This fact suggests that ``outer'' regions of NFW halos might be related to equilibrium states in the non--extensive Statistical Mechanics formalism proposed by Tsallis.Comment: 6 pages, 1 figur

    Informes - II Reunión plenaria de mitad del proyecto "Fastos, simulacros y saberes en la América Virreinal"

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    Estos informes son resultado del proyecto «Fastos, simulacros y saberes en la América Virreinal» (PID2020-113841GB-I00), han participado: WP AGENCIA FEMENINA. Coordina Beatriz Ferrús. EQUIPO: Julia Lewandowska, Beatriz Colombi, Sarah Serrano y Sara Poot Herrera WP ESPACIO Y CARTOGRAFÍA SIMBÓLICA. Coordina Eva Valero. EQUIPO: María José Rodilla y Jorge Mojarro WP ALTERIDADES, IDENTIDAD Y DEVOCIONES. Coordina Alberto Baena. EQUIPO: Antonio Rubial, Elena Manchado y Alejandro Cañeque WP CULTURA MATERIAL Y VISUAL. Coordina Francisco Montes. EQUIPO: Andreia Martins, Roberto Junco y Renata Schneider WP FASTO Y SIMULACRO. Coordina Judith Farré Vidal Este DATASET está sujeto a una licencia CC BY-NC-ND 4.0Los informes que se presentan son resultado de las sesiones que conformaron la reunión plenaria de mitad del proyecto «Fastos, simulacros y saberes en la América Virreinal» (PID2020-113841GB-I00) celebrada en 2023 (https://www.archivocolonial.csic.es/nuestra-actividad/ii-reunion-plenaria-del-proyecto/) . Todos los miembros del proyecto se organizaron en grupos de trabajo (WP) para previamente trazar un estado de la cuestión de cada una de las líneas transversales del proyecto (ver infografía en los documentos). El coordinador de cada línea de investigación se encargó de recoger, elaborar y unificar la información de cada WP, que ahora presentamos como un conjunto de informes de trabajo.N
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