Phase synchronization of coupled bursting neurons and the generalized Kuramoto model

Bursting neurons fire rapid sequences of action potential spikes followed by a quiescent period. The basic dynamical mechanism of bursting is the slow currents that modulate a fast spiking activity caused by rapid ionic currents. Minimal models of bursting neurons must include both effects. We considered one of these models and its relation with a generalized Kuramoto model, thanks to the definition of a geometrical phase for bursting and a corresponding frequency. We considered neuronal networks with different connection topologies and investigated the transition from a non-synchronized to a partially phase-synchronized state as the coupling strength is varied. The numerically determined critical coupling strength value for this transition to occur is compared with theoretical results valid for the generalized Kuramoto model.Comment: 31 pages, 5 figure

Problemáticas da educação física I

info:eu-repo/semantics/publishedVersio

On the Richardson-Lucy Algorithm with A Varying Point Spread Function along The Iterations

Abstract: This work analyses the soundness of two algorithms, Fishsint and Almexp to improve images using the Richardson-Lucy (RL) algorithm under a varying Point Spread Function (PSF) along the iterations. A plethora of methods based on Richardson-Lucy has been published, but no further proposal involving such an alternative has been published. Whereas the unnamed predecessor of Fishsint addressed only small size synthetic images under a blind fashion procedure, Fishsint and Almexp employs an algorithm Wdet to determine the initial PSF and all subsequent values after each iteration, respectively. Fishsint performs a loop, where the last determined PSF improves the previously obtained image and vice versa. Its original unnamed version has been modified in the present work by entering a previously determined initial PSF to accelerate the convergence. The algorithm Almexp, as well, uses the algorithm Wdet to determine the PSF of the last obtained image to deconvolve itself. Therefore, whereas the Fishsint unnamed predecessor used an initial guess PSF - chosen by the customer - Almexp determines the PSF always through the algorithm Wdet. Fishsint and Almexp furnish final images which outperform those obtained with the original Richardson-Lucy approach working under a constant PSF along the iterations. Hence, in order to carry out a comparison between their performances, all the algorithms have been embedded into an ad hoc written Fortran 90 program. The results corroborate the soundness of a varying PSF along the iterations with the Richardson Lucy algorithm. Keywords: Richardson-Lucy, varying PSF along iterations, image improvement, neutron radiograph

Problemáticas da educação física II

info:eu-repo/semantics/publishedVersio

Mathematical model of brain tumour with glia-neuron interactions and chemotherapy treatment

Acknowledgements This study was possible by partial financial support from the following Brazilian government agencies: Fundação Araucária, EPSRC-EP/I032606/1 and CNPq, CAPES and Science Without Borders Program Process nos. 17656125, 99999.010583/2013-00 and 245377/2012-3.Peer reviewedPreprin

Using educational robotics in pre-service teacher training : orchestration between an exploration guide and teacher role

The proper integration of technology in teaching and learning processes must consider the role of teachers and students, as well as the design of tasks and the context in which they are implemented. Teachers’ perceived self-efficacy significantly influences their willingness to integrate educational robotics (ER) into their practice, so initial teacher training should provide opportunities for teachers to participate in structured activities that integrate ER. In this study, a class of pre-service teachers from an initial teacher training programme were provided with their first contact with an ER platform through the use of a simulator. We present the design process of a student exploration guide and teacher guide, developed over three iterative cycles of implementation, assessment and redesign. The analysis of the data collected allowed for improvements in the design of the tasks, the graphic component of the student exploration guide, and more precise indications for the teacher’s actions. The main contribution of this study is the chain orchestration between the simulator, student exploration guide and teacher guide, which allowed pre-service teachers to solve a set of challenges of increasing complexity, thereby progressively decreasing their difficulties and contributing to an adequate integration of ER in their future teaching practices.info:eu-repo/semantics/publishedVersio

NEW FOSSIL RECORDS OF PLEISTOCENE MARINE MOLLUSKS IN SOUTHERN BRAZIL

Fossils of the gastropods Diodora patagonica, Zidona dufresnei, Olivancillaria carcellesi, Lamniconus lemniscatus carcellesi and the bivalve Arcinella brasiliana are registered for the first time from the outcrops of Chui Creek, on the coastal plain of Rio Grande do Sul State, southernmost Brazil, together with other taxa previously known elsewhere. The specimens were collected in a shallow Pleistocene marine facies exposed at the base of the banks of the creek, in a fossil concentration possibly formed by storm events. The taxa described here live in shallow environments (with the exception of A. brasiliana and Z. dufresnei) with sandy bottoms (except for D. patagonica, T patagonica, B. odites, C. rhizophorae and A. brasiliana). The presence of L. lemniscatus carcellesi, found living today only in Uruguay and Argentina, indicates a wider distribution for this taxon during the late Pleistocene.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico - CNP

Guest Editorial Special Issue on Security and Forensics of Internet of Things: Problems and Solutions

The Internet of Things (IoT) has experienced significant growth over recent years and Gartner predicts that, by 2020, 21 billion IoT endpoints will be in use. The potential behind widespread usage of small devices capable of collecting, transmitting, or acting upon data has been fueling interest both from industry and academia. Security and forensics are two of the topics facing major challenges in this paradigm, on par with or even more prominent than other computing paradigms. Aspects such as low processing power and small storage capacity of such IoT devices contribute to their typically poor built-in security and forensics capabilities. Their reliance on cloud computing and mobile apps to operate and provide services increases the attack surface, distributing the collection of digital evidence and making reconstruction activities (to answer questions as what, where, when, who, why, and how) harder