1,359 research outputs found
Stochastic synaptic plasticity in deterministic aVLSI networks of spiking neurons
No full textChicca E, Fusi S. Stochastic synaptic plasticity in deterministic aVLSI networks of spiking neurons. In: Rattay F, ed. Proceedings of the World Congress on Neuroinformatics. Vienna: ARGESIM/ASIM Verlag; 2001: 468-477.Stochastic learning solves the stability-plasticity problem (Fusi et al., 2000a)
but raises new issues related to the generation of the proper noise driving
the synaptic dynamics. Here we show that a simple, fully deterministic,
spike-driven synaptic device can make use of the network generated vari-
ability in the neuronal activity to drive the required stochastic mechanism.
Randomness emerges naturally from the interaction of deterministic neu-
rons, and no extra source of noise is needed. Learning and forgetting
rates of the network can be easily controlled by changing the statistics of
the spike trains without changing any inherent parameter of the synaptic
dynamics
Cu-ZSM-5 (Si/Al=66), Cu-Fe-S-1 (Si/Fe=66) and Cu-S-1 catalysts for NO decomposition: preparation, analytical characterization and catalytic activity
No full textWe prepared H-ZSM-5 (Si/Al = 66), Fe-S-1 (Si/Fe = 66), and Silicalite-1 (S-1) according to the methods described by Bellussi and coworkers, and compared their ion-exchange capacity for copper ions. The Cu-ZSM-5, Cu-Fe-S and Cu-S-1 samples thus obtained have been investigated as catalysts for the NO decomposition reaction at 773 K. We found that using copper acetate solutions with concentrations in the range 0.004 M less than or equal to[Cu2+]less than or equal to 0.1 M, at room temperature and at 323 K, it is very easy to prepare overexchanged Cu-ZSM-5, Cu-Fe-S-1, and Cu-S-1 catalysts. XRD and Vis-UV DRS techniques show that after thermal treatments of the fresh samples in air at 823 K for 4 h no segregation of bulk CuO phase occurs, suggesting the presence of low nuclearity [CunOx(OH)(y)](q+) species [q=2(n-x)-y greater than or equal to 0]. These results were confirmed by TPR studies. At 773 K, only Cu-ZSM-5 and Cu-Fe-S-1 catalysts showed NO decomposition activity (NO 1% in He, W/F = 0.2 g s cm(-3)). Instead, the activities of Cu-S-1 and of the copper-free matrices (S-1, H-ZSM-5 and Fe-S-1) were not measurable under our experimental conditions. The negative results obtained with Cu-S-1 catalysts clearly demonstrate that the active sites for NO decomposition in Cu-MFI catalysts consist of polynuclear ionic copper species strongly anchored to framework [MO4](-) species (M=Al, Fe)
Valdo Fusi Square
No full textPubblicazione del progetto per la piazza/giardino e il parcheggio Valdo Fusi a Torino
Fusi da sonno in sindromi extrapiramidali.
No full textI nuclei della base sono stati ritenuti importanti nella produzione dello spindling nel corso del sonno. Sono stati studiati i fusi da sonno in malattie del sistema extrapiramidale mediante un'analisi che utilizza il fiiltraggio digitale del segnale EEG rendendo automatica ed oggettiva la lettura e il conteggio dei fusi. Il dato principale che emerge dallo studio è che l'alterazione più caratteristica del sonno notturno riguarda i fusi da sonno. Infatti lo spindling è risultato inferiore nei pazienti con parkinsonismo ed ipertonia, mentre era aumentato nei pazienti coreici ed ipotonia. Nel primo caso l'alterazione potrebbe essere sottesa da carenza di attività dopaminergica, mentre nel secondo caso da un eccesso della stessa attività
Synthesis and Characterization of 3-Hydroxy-2-(5'-Hydroxypentyl)-4H-Pyran-4-one and Study of Its Complexation with Iron(III)
No full textAbstract: With the special focus to obtain a new tridentate ligand able to coordinate Fe(III), 3-hydroxy-2-(5'-hydroxypentyl)-4H-pyran-4-one (5-H) has been synthesized. Iron/ligand solution chemistry has been investigated in aqueous solution by ESI-MS and cyclic voltammetric measurements. The physiologic predominant specie is the tris-chelate complex as Job test attested. The electrode potential of the [FeIII(5)3]/[FeII(5)3]– couple was evaluated to be –0.54 V vs. SCE, pH 7.4
A comparison between Cu-ZSM-5, Cu-S-1 and Cu-mesoporous-silica-alumina as catalysts for NO decomposition
No full textWe prepared H-ZSM-5 (Si/Al=80), amorphous mesoporous silica-alumina (MSA, Si/Al=90), and Silicalite-1 (S-1) according to the methods described by Bellussi and co-workers, and compared their ion-exchange capacity for copper ions. The Cu-ZSM-5, Cu-MSA and Cu-S-1 samples thus obtained have been investigated as catalysts for the NO decomposition reaction at 773 K. We found that using copper acetate solutions with concentrations in the range 0.008 M≤[Cu 2+]≤0.1 M, both at room temperature arid at 323 K, it is very easy to prepare over-exchanged Cu-ZSM-5, Cu-S-1 and Cu-MSA catalysts. XRD and Vis-UV DRS techniques show that after thermal treatments of the fresh samples in air at 823 K for 4 h no segregation of CuO phase occurs, suggesting the presence of low nuclearity [Cu(n)O(x)(OH)(y)](q+) species (q=2(n-x)-y≥0). These results were confirmed by TPR studies. At 773 K only over-exchanged Cu-ZSM-5 catalysts showed NO decomposition activity (NO 1% in He, W/F=0.1 gs/cm 3) with a turnover frequency essentially determined by the Si/Al ratio, in agreement with previous literature data. Instead, the activity of Cu-S-1 and Cu-MSA catalysts was not measurable under our experimental conditions. The present results confirm that the framework topology and the presence of framework AlO 4/ - species are fundamental to develop active copper species for NO decomposition. It is demonstrated that the active sites in Cu-ZSM-5 consist of copper species strongly anchored to framework AlO 4/ - species. The most active sites, as they occur only on ZSM-5 support with the lower Si/Al atomic ratios, might consist of dimeric Cu species (Cu +···Cu 2+···O -) strongly anchored to next-nearest-neighbour framework AlO 4 - species.
We prepared H-ZSM-5 (Si/Al=80), amorphous mesoporous silica-alumina (MSA, Si/Al=90), and Silicalite-1 (S-1) according to the methods described by Bellussi and co-workers, and compared their ion-exchange capacity for copper ions. The Cu-ZSM-5, Cu-MSA and Cu-S-1 samples thus obtained have been investigated as catalysts for the NO decomposition reaction at 773 K. We found that using copper acetate solutions with concentrations in the range 0.008 M≤[Cu 2+]≤0.1 M, both at room temperature and at 323 K, it is very easy to prepare over-exchanged Cu-ZSM-5, Cu-S-1 and Cu-MSA catalysts. XRD and Vis-UV DRS techniques show that after thermal treatments of the fresh samples in air at 823 K for 4 h no segregation of CuO phase occurs, suggesting the presence of low nuclearity [Cu nO x(OH) y] q+ species (q=2(n-x)-y≥0). These results were confirmed by TPR studies. At 773 K only over-exchanged Cu-ZSM-5 catalysts showed NO decomposition activity (NO 1% in He, W/F=0.1 gs/cm 3) with a turnover frequency essentially determined by the Si/Al ratio, in agreement with previous literature data. Instead, the activity of Cu-S-1 and Cu-MSA catalysts was not measurable under our experimental conditions. The present results confirm that the framework topology and the presence of framework AlO 4 - species are fundamental to develop active copper species for NO decomposition. It is demonstrated that the active sites in Cu-ZSM-5 consist of copper species strongly anchored to framework AlO 4 - species. The most active sites, as they occur only on ZSM-5 support with the lower Si/Al atomic ratios, might consist of dimeric Cu species (Cu +...Cu 2+...O -) strongly anchored to next-nearest-neighbour framework AlO 4 - species.
Medical education and attitudes about acute otitis media guidelines: a survey of Italian pediatricians and otolaryngologists.
No full text(0) Save to: more options
Medical Education and Attitudes About Acute Otitis Media Guidelines A Survey of Italian Pediatricians and Otolaryngologists
Author(s): Marchisio, P (Marchisio, Paola); Mira, E (Mira, Eugenio)2; Klersy, C (Klersy, Catherine)3; Pagella, F (Pagella, Fabio)2; Esposito, S (Esposito, Susanna); Bianchini, S (Bianchini, Sonia); Di Mauro, G (Di Mauro, Giuseppe)4; Fusi, M (Fusi, Michela); Nazzari, E (Nazzari, Erica); Tagliabue, M (Tagliabue, Marta)2; Bellussi, L (Bellussi, Luisa)5; Principi, N (Principi, Nicola)1
Source: PEDIATRIC INFECTIOUS DISEASE JOURNAL Volume: 28 Issue: 1 Pages: 1-4 DOI: 10.1097/INF.0b013e318184ef02 Published: JAN 2009
Times Cited: 7 (from Web of Science)
Cited References: 36 [ view related records ] Citation Map
Abstract: Background: Medical education and guidelines have been advocated as major means of improving the managernent of otitis media. Limited data are available concerning medical education in acute otitis media (AOM), and the association between medical education and attitudes about AOM guidelines has never been explored.
Objectives: To assess the prevalence of medical education concerning AOM, of a Positive attitude toward AOM guidelines and of appropriate diagnostic methods in a large sample of Italian pediatricians (PEDs) and otolaryngologist (ENTs) and to look for possible associations between them.
Subjects and Methods: This cross-sectional survey was based on the responses of 2012 physicians (1160 PEDs and 852 ENTs) to a mailed anonymous questionnaire.
Results: Very few (9%) of the responders had received any AOM medical education during Medical school, but the number increased (hiring residency (38%) and peaked in the postresidency period (53%) with slight differences between PEDs and ENTs. Forty percent reported a positive attitude toward AOM guidelines, with PEDs having a better attitude than ENTs (46% vs. 32%, P < 0.001), An appropriate diagnostic method for AOM was reported by only 21% of the physicians (PEDs 11% vs. ENTs 35%, P < 0.001). AOM Medical education during postresidency and reporting the use of appropriate diagnostic methods were significantly associated With a positive attitude about AOM guidelines.
Conclusions: Specific educational programs concerning AOM should be implemented and rigorously evaluated, before physicians become fully trained PEDs and ENTs, and maintained during postresidency. Evidence-based guidelines should be further incorporated into everyday practice of both PEDs and ENTs
The response of cortical neurons to in vivo-like input current: theory and experiment: I. Noisy inputs with stationary statistics.
No full textThe study of several aspects of the collective dynamics of interacting neurons can be highly simplified if one assumes that the statistics of the synaptic input is the same for a large population of similarly behaving neurons (mean field approach). In particular, under such an assumption, it is possible to determine and study all the equilibrium points of the network dynamics when the neuronal response to noisy, in vivo-like, synaptic currents is known. The response function can be computed analytically for simple integrate-and-fire neuron models and it can be measured directly in experiments in vitro. Here we review theoretical and experimental results about the neural response to noisy inputs with stationary statistics. These response functions are important to characterize the collective neural dynamics that are proposed to be the neural substrate of working memory, decision making and other cognitive functions. Applications to the case of time-varying inputs are reviewed in a companion paper (Giugliano et al. in Biol Cybern, 2008). We conclude that modified integrate-and-fire neuron models are good enough to reproduce faithfully many of the relevant dynamical aspects of the neuronal response measured in experiments on real neurons in vitro
Riconoscimento e misura automatica dei fusi da sonno mediante filtraggio digitale
No full textViene descritto un metodo di misura automatica della distribuzione della durata dei fusi da sonno che avviene attraverso tre susseguenti fasi: digitalizzazione dell'EEG, riconoscimento dei fusi, misura dei fusi. Il segnale EEG, registrato su nastro magnetico viene digitalizzato con una strumentazione elettronica CAMAC collegata in linea a un calcolatore PDP 11/45. Con una routine di Fast Fourier Transform si effettua una trasformazione dal dominio del tempo al dominio delle frequenze. Qui si attua il filtraggio della banda di frequenza da 12 a 16 Hz caratteristiche dei fusi da sonno in esame. Con un'operazione di antitrasformata si ottiene il segnale filtrato nel dominio del tempo a cui si applica il processo di misurare della lunghezza temporale dei fusi
S. Balloni, Le campagne elettorali di Ippolito Niccolini (1882-1890), Polistampa, Firenze 2017,
No full text- …
