1,358,019 research outputs found
Progettare futuri possibili : Pluralismo dei paradigmi e Tras-formazione
No full textIl volume Progettare futuri possibili: pluralismo dei paradigmi e tras-formazione è il
frutto di un confronto interdisciplinare nato dalla summer school di ricerca organizzata
dalla Società di ricerca Educativa e Formativa (SIREF) nel settembre 2024,
che esplora in profondità le sfide educative, sociali e culturali del nostro tempo. Il
titolo stesso ne anticipa il percorso: progettare il futuro significa confrontarsi con
la complessità del presente, riconoscendo il pluralismo dei saperi e adottando approcci
trasformativi capaci di generare orizzonti di possibilità
Extracting the Motor Program of Handwriting from its Lognormal Representation
No full textLognormality has proven to be an effective way for handwriting modeling. It assumes that handwriting is a time superimposition of a sequence of commands issued by the motor system, each command producing a stroke, i.e. a movement with a lognormal velocity profile. Motor control theories, moreover, suggest that handwriting movements result from both central and peripheral control, thus assuming that some movements of the sequence may not be encoded into the stored motor program but rather generated peripherally to keep the action as close as possible to the intended one. In the light of those observations, we present an algorithm for segmenting handwriting movements into strokes, each of which corresponds to a command stored into the motor program, while disregarding those that may depend on peripheral control. Experiments on handwriting samples show that the proposed algorithm detects the same number of strokes across multiple executions of a handwriting task by the same subject, and this set of strokes provides also a good reconstruction of the action
Francesco Filelfo, Corrispondenza. I. Lettere volgari. Edizione critica e commento a cura di Nicoletta Marcelli
No full textNel panorama dell’umanesimo italiano a fianco di numerosi e celebri autori che, sull'esempio di Francesco Petrarca, si dedicarono alla composizione di un epistolario latino, possiamo annoverarne altrettanti per ciò che concerne l’epistolografia in volgare, ma, assai rari sono i casi di umanisti che per la scrittura di lettere si siano cimentati sul doppio registro latino-volgare e, nel caso di Filelfo, con l’aggiunta del greco.
Se all’Epistolario latino e greco, raccolto, rielaborato e concepito con le caratteristiche di una vera e propria opera letteraria destinata alla pubblicazione Filelfo dedicò notevoli cure per molti anni, alle lettere volgari, al contrario, l’autore non riconobbe uno statuto letterario, per cui la loro sorte è stata quella della totale dispersione, al punto che non se ne conosceva neppure il numero complessivo. Grazie a questo lavoro il corpus conta oggi 141 lettere, parte delle quali sconosciute e inedite, in larga misura autografe, indirizzate ad alcune tra le maggiori personalità della politica e della cultura del Quattrocento: fra tutti spiccano i duchi Francesco e Galeazzo Maria Sforza, Lorenzo il Magnifico e il cancelliere sforzesco Cicco Simonetta. Le lettere toccano molti aspetti della storia e della cultura del secolo XV, dalla politica, alla diplomazia, dalle humanae litterae, alla biografia di Filelfo stesso. Nella loro varietà rispecchiano a pieno la poliedrica personalità dell’autore, il cui profilo intellettuale appare mirabilmente definito nell'ampio percorso della sua Corrispondenza, che si completa con gli altri corpora previsti dal progetto (epistole greche, latine, estravaganti), entro il quale questo primo volume si inscrive
Do handwriting difficulties of Parkinson's patients depend on their impaired ability to retain the motor plan? A pilot study
No full textPatients affected by Parkinson’s disease (PD) show deficits in learning novel motor behaviors and executing previously acquired ones. We investigated whether the two phenomena are related, evaluating the hypothesis that PD patients have difficulties in executing fine movements (such as handwriting) acquired before the onset of the disease since they perform the task as they are executing it for the first time. We asked healthy subjects to write a sequence of ‘l’ on a digitizer tablet by drawing the loop of the letter in counterclockwise fashion (as they are used to do) and clockwise fashion (i.e. using a novel motor plan). We compared the kinematic features of the samples produced by healthy subjects to those measured in samples produced by PD patients. We focused the analysis on the ink trace segmentation points, which represent the starting/ending points of the elementary handwriting movements. Our results suggests that deficits observed in PD patients in executing both novel tasks (reduced learning performance compared to controls) and previously acquired task (disrupted kinematic features compared to controls) could be due to the same underlying deficit, i.e. impaired ability of PD patients to retain the motor plan associated to the task
Do synthetic generated signatures reflect the subject motor programs? A pilot study
No full textHandwritten signature is a biometric trait used for verifying a person’s identity. Automatic signature verification systems typically require a lot of specimens in order to model the signing habit of a subject but, in a real scenario, few signature samples are available. To overcome this problem, methods for creating human-like duplicated signatures using one real signature per subject and based on sigma lognormal decomposition have been proposed in literature. In this paper, we evaluate if duplicated signatures show the same amount of variability observed in real signatures by detecting and analysing signature stability regions. In particular, we investigate if real and duplicated signatures could be the instances of a similar motor program. Experimental results on a standard dataset show that in some cases duplication methods introduce a variability that is greater than the writer's variability to such an extent to generate motor programs that do not belong to the writer's repertoire. Results suggest that a connection exists between trajectory plan and motor plan parameters, which cannot be modified independently one from the other in order to generate synthetic signatures that reflect the writer’s motor program repertoire
Existence of Bounded Trajectories Via Upper and Lower Solutions
No full textThe paper deals with the boundary value problem (on the whole line) u''-f(u,u')+g(u)=0, u(-∞)=0, u(+∞)=1, where g is a continuous non-negative function with support [0, 1], and f is a continuous function. By means of a new approach, based on a combination of lower and upper-solutions methods and phase-plane techniques, we prove an existence result for the problem when f is superlinear in u'; by a similar technique, we also get a non-existence one. As an application, we investigate the attractivity of the singular point (0,0) in the phase-plane (u, u'). Applications of these results in the field of front-type solutions for reaction diffusion equations can be found in L. Malaguti, C. Marcelli, Math. Nachr. 242 (2002), 148—16
The Role of Three-Body Interactions on the Equilibrium and Non-Equilibrium Properties of Fluids from Molecular Simulation
No full textThe aim of this work is to use molecular simulation to investigate the role of
three-body interatomic potentials in noble gas systems for two distinct
phenomena: phase equilibria and shear flow. In particular we studied the
vapour-liquid coexisting phase for pure systems (argon, krypton and x enon) and
for an argon-krypton mixture, utilizing the technique called Monte Carlo Gibbs
ensemble. We also studied the dependence of the shear viscosity, pressure and
energy with the strain rate in planar Couette flow, using a non-equilibrium
molecular simulation (NEMD) technique.
The results we present in this work demonstrate that three-body interactions
play an important role in the overall interatomic interactions of noble gases. This
is demonstrated by the good agreement between our simulation results and the
experimental data for both equilibrium and non-equilibrium systems.
The good results for vapour-liquid coexisting phases encourage performing
further computer simulations with realistic potentials. This may improve the
prediction of quantities like critical temperature and density, in particular of
substances for which these properties are difficult to obtain from experiment.
We have demonstrated that use of accurate two- and three-body potentials for
shearing liquid argon and xenon displays significant departure from the
expected strain rate dependencies of the pressure, energy and shear viscosity.
For the first time, the pressure is convincingly observed to vary linearly with an
apparent analytic g&2 dependence, in contrast to the predicted g&3/ 2 dependence
of mode -coupling theory. Our best extrapolation of the zero -shear viscosity for
argon gives excellent agreement (within 1%) with the known experimental data.
To the best of our knowledge, this the first time that such accuracy has been
achieved with NEMD simulations. This encourages performing simulations with
accurate potentials for transport properties
L’imprenditore: teoria e storia sul lungo periodo
No full textL’imprenditorialità è un tema che suscita grande interesse, la cui esplo- razione storica rimane tuttavia ancora incompleta, specialmente se ci si riferisce al periodo antecedente alla nascita delle grandi imprese mo- derne. Anche lo studio dell’essenza e del ruolo dell’imprenditore non ha ancora ricevuto l’attenzione che merita. Questo volume approfondisce il tema dell’imprenditorialità da una prospettiva di lungo periodo, valu- tando il suo sviluppo e l’influenza che ha avuto sul sistema economico e sociale nel corso dei secoli. Attraverso l’esame di casi studio emblemati- ci, mira a far comprendere pienamente la centralità del ruolo degli im- prenditori come agenti di trasformazione e innovazione, offrendo spunti preziosi di riflessione su come queste figure visionarie abbiano generato progresso e prosperità
A Multiscale Approach to the Elastic Moduli of Biomembrane
No full textWe develop equilibrium fluctuation formulae for the isothermal elastic moduli of discrete biomembrane models at different scales. We account for the coupling of large stretching and bending strains of triangulated network models endowed with harmonic and dihedral angle potentials, on the basis of the discrete-continuum approach presented in Schmidt and Fraternali (J Mech Phys Solids 60:172–180, 2012). We test the proposed equilibrium fluctuation formulae with reference to a coarse-grained molecular dynamics model of the red blood cell (RBC) membrane (Marcelli et al. in Biophys J 89:2473–2480, 2005; Hale et al. in Soft Matter 5:3603–3606, 2009), employing a local maximum-entropy regularization of the fluctuating configurations (Fraternali et al. in J Comput Phys 231:528–540, 2012). We obtain information about membrane stiffening/softening due to stretching, curvature, and microscopic undulations of the RBC model. We detect local dependence of the elastic moduli over the RBC membrane, establishing comparisons between the present theory and different approaches available in the literature
A computational model-based analysis of cerebellar plasticity in motor learning
No full textThe Cerebellum is involved in many cognitive and motor functions. This work focuses on the inspection of the role of the Cerebellum during motor learning. The investigation is led through simulation of
a computational model representing the types and the connections of the different cerebellar neural structures. We inspect the role and the function of the main actor in cerebellar learning: the synaptic plasticity mechanism. The presence of different plasticity sites has been reported in the Cerebellum and this work aims at analysing the role of the two mechanisms of synaptic plasticity: Long-Term Depression (LTD) and Long Term Potentiation (LTP). We want to inspect their relevance in every site and the contribution of the site itself during motor learning. We have investigated the role of the Cerebellum in three different tasks: learning motor behaviours, acquiring conditioned responses and adapting the natural vestibulo-ocular reflex (VOR). We have also simulated lesion-based scenario where we caused artificial lesions at granule cells, the input processing units for all the analysed tasks. Our work remarks some results reported in literature and also leads to some new considerations about the role of some plasticity sites
- …
