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Search Results: 1 - 10 of 6883 matches for " Federico Rossi "
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Investigation on Thermophysical Properties of Thymic Cell Cultures Exposed to Electromagnetic Fields
Federico Rossi,Andrea Nicolini
Environment and Pollution , 2012, DOI: 10.5539/ep.v2n1p11
Abstract: The paper deals with an investigation of the possible effects of RF electromagnetic fields towards the environment and human health. An experimental facility was designed and built and in vitro experiments were carried out on thymic cell cultures. They were exposed for three and six hours to 144 MHz RF electromagnetic fields. The effects were analysed in terms of the possible variation of their thermophysical properties (density, viscosity, specific heat). Results showed that the tested configuration does not induce alterations of the thermophysical properties of the tested cell cultures.
Distributed consensus with mixed time/communication bandwidth performance metrics
Federico Rossi,Marco Pavone
Computer Science , 2014,
Abstract: In this paper we study the inherent trade-off between time and communication complexity for the distributed consensus problem. In our model, communication complexity is measured as the maximum data throughput (in bits per second) sent through the network at a given instant. Such a notion of communication complexity, referred to as bandwidth complexity, is related to the frequency bandwidth a designer should collectively allocate to the agents if they were to communicate via a wireless channel, which represents an important constraint for dense robotic networks. We prove a lower bound on the bandwidth complexity of the consensus problem and provide a consensus algorithm that is bandwidth-optimal for a wide class of consensus functions. We then propose a distributed algorithm that can trade communication complexity versus time complexity as a function of a tunable parameter, which can be adjusted by a system designer as a function of the properties of the wireless communication channel. We rigorously characterize the tunable algorithm's worst-case bandwidth complexity and show that it compares favorably with the bandwidth complexity of well-known consensus algorithm.
On the fundamental limitations of performance for distributed decision-making in robotic networks
Federico Rossi,Marco Pavone
Computer Science , 2014,
Abstract: This paper studies fundamental limitations of performance for distributed decision-making in robotic networks. The class of decision-making problems we consider encompasses a number of prototypical problems such as average-based consensus as well as distributed optimization, leader election, majority voting, MAX, MIN, and logical formulas. We first propose a formal model for distributed computation on robotic networks that is based on the concept of I/O automata and is inspired by the Computer Science literature on distributed computing clusters. Then, we present a number of bounds on time, message, and byte complexity, which we use to discuss the relative performance of a number of approaches for distributed decision-making. From a methodological standpoint, our work sheds light on the relation between the tools developed by the Computer Science and Controls communities on the topic of distributed algorithms.
Cohomology of D-complex manifolds
Daniele Angella,Federico A. Rossi
Mathematics , 2012, DOI: 10.1016/j.difgeo.2012.07.003
Abstract: In order to look for a well-behaved counterpart to Dolbeault cohomology in D-complex geometry, we study the de Rham cohomology of an almost D-complex manifold and its subgroups made up of the classes admitting invariant, respectively anti-invariant, representatives with respect to the almost D-complex structure, miming the theory introduced by T.-J. Li and W. Zhang in [T.-J. Li, W. Zhang, Comparing tamed and compatible symplectic cones and cohomological properties of almost complex manifolds, Comm. Anal. Geom. 17 (2009), no. 4, 651-684] for almost complex manifolds. In particular, we prove that, on a 4-dimensional D-complex nilmanifold, such subgroups provide a decomposition at the level of the real second de Rham cohomology group. Moreover, we study deformations of D-complex structures, showing in particular that admitting D-Kaehler structures is not a stable property under small deformations.
Isotopic Effect on the Kinetics of the Belousov-Zhabotinsky Reaction
Federico Rossi,Mauro Rustici,Claudio Rossi,Enzo Tiezzi
International Journal of Molecular Sciences , 2007, DOI: 10.3390/i8090943
Abstract: In this work we present results about the deuterium isotope effect on the globalkinetics of a Belousov-Zhabotinsky reaction in batch conditions. A nonlinear dependenceof the Induction Period upon the percentage of deuterated reactants was found. The isotopiceffect on the bromination reaction of malonic acid was evaluated.
Evaluation and Optimization of an Innovative Low-Cost Photovoltaic Solar Concentrator
Franco Cotana,Federico Rossi,Andrea Nicolini
International Journal of Photoenergy , 2011, DOI: 10.1155/2011/843209
Abstract: Many researches showed that the cost of the energy produced by photovoltaic (PV) concentrators is strongly reduced with respect to flat panels, especially in those countries that have a high solar irradiation. The cost drop comes from the reduction of the expensive high-efficiency photovoltaic surface through the use of optical concentrators of the solar radiation. In this paper, an experimental innovative PV low-concentration system is analysed. Numerical simulations were performed to determine the possible reasons of energy losses in the prototype, primarily due to geometrical factors. In particular, the effect of the shadows produced from the mirrors on the prototype performances was analysed: shadows are often neglected in the design phase of such systems. The study demonstrates that shadows may affect the performances of a hypothetical optimized PV low-concentration system up to 15%. Finally, an economical evaluation was carried out comparing the proposed optimized system to a traditional flat PV panel. 1. Introduction Solar energy is a huge free resource for the world energetic demand. Direct conversion of sunlight into electricity in PV cells is one of the main solar active technologies, the two others being concentrating solar power (CSP) and solar thermal collectors for heating and cooling [1]. PV cells provide 0.1% of the global electricity generation and are projected to provide 5% of global electricity consumption in 2030, rising up to 11% in 2050 [2]. Many researches showed that the cost of the energy produced by traditional flat PV panels may be reduced by PV concentrators [3–5]. Since semiconductor material is the most expensive part of the PV system and PV cells can theoretically produce more energy if exposed to higher sunlight fluxes, PV concentrators are based on focusing a large amount of solar radiation on a small surface of high-efficiency PV cells. Different concentrator systems were proposed in the past years [3]: however, their economic suitability was limited by the low availability of PV cells able to work in concentrating conditions, the problems in implementing efficient PV cooling systems, the necessity of efficient and cheap solar tracking systems. Nowadays, these technologies reached, for different reasons, a good development level. However, medium and high PV concentration systems (resp. with 20–500x and over 500x concentration levels) need expensive multijunction PV cells which are characterized by high efficiency but a performance drop when they are installed in hot environments (such as deserts) [6, 7]. Furthermore,
Golgi Cell-Mediated Activation of Postsynaptic GABAB Receptors Induces Disinhibition of the Golgi Cell-Granule Cell Synapse in Rat Cerebellum
Federico Brandalise, Urs Gerber, Paola Rossi
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0043417
Abstract: In the cerebellar glomerulus, GABAergic synapses formed by Golgi cells regulate excitatory transmission from mossy fibers to granule cells through feed-forward and feedback mechanisms. In acute cerebellar slices, we found that stimulating Golgi cell axons with a train of 10 impulses at 100 Hz transiently inhibited both the phasic and the tonic components of inhibitory responses recorded in granule cells. This effect was blocked by the GABAB receptor blocker CGP35348, and could be mimicked by bath-application of baclofen (30 μM). This depression of IPSCs was prevented when granule cells were dialyzed with GDPβS. Furthermore, when synaptic transmission was blocked, GABAA currents induced in granule cells by localized muscimol application were inhibited by the GABAB receptor agonist baclofen. These findings indicate that postsynaptic GABAB receptors are primarily responsible for the depression of IPSCs. This inhibition of inhibitory events results in an unexpected excitatory action by Golgi cells on granule cell targets. The reduction of Golgi cell-mediated inhibition in the cerebellar glomerulus may represent a regulatory mechanism to shift the balance between excitation and inhibition in the glomerulus during cerebellar information processing.
Model Predictive Control of Autonomous Mobility-on-Demand Systems
Rick Zhang,Federico Rossi,Marco Pavone
Computer Science , 2015,
Abstract: In this paper we present a model predictive control (MPC) approach to optimize vehicle scheduling and routing in an autonomous mobility-on-demand (AMoD) system. In AMoD systems, robotic, self-driving vehicles transport customers within an urban environment and are coordinated to optimize service throughout the entire network. Specifically, we first propose a novel discrete-time model of an AMoD system and we show that this formulation allows the easy integration of a number of real-world constraints, e.g., electric vehicle charging constraints. Second, leveraging our model, we design a model predictive control algorithm for the optimal coordination of an AMoD system and prove its stability in the sense of Lyapunov. At each optimization step, the vehicle scheduling and routing problem is solved as a mixed integer linear program (MILP) where the decision variables are binary variables representing whether a vehicle will 1) wait at a station, 2) service a customer, or 3) rebalance to another station. Finally, by using real-world data, we show that the MPC algorithm can be run in real-time for moderately-sized systems and outperforms previous control strategies for AMoD systems.
L’immunogenicità nella cavia e nel cavallo di due formulazioni di un vaccino inattivato e adiuvato per la peste equina
Gaetano Federico Ronchi,Simonetta Ulisse,Emanuela Rossi,Paola Franchi
Veterinaria Italiana , 2012,
Abstract: L’efficacia di due vaccini monovalenti, inattivati e adiuvati per il controllo della Peste Equina, allestiti con i sierotipi 5 e 9, è stata saggiata su cavia per selezionare la formulazione con le migliori capacità immunogene. Nella formulazione dei vaccini sono state prese in considerazione: la risposta immunitaria evocata nella cavia e le proprietà infiammatorie di due diversi tipi di adiuvanti precedentemente saggiati nella specie di destino del vaccino.Il vaccino allestito con il sierotipo 9, saggiato in uno studio pilota su cavallo, si è dimostrato capace fin dalla prima somministrazione di stimolare la produzione di anticorpi neutralizzanti. La risposta anticorpale evocata ha subito un marcato rialzo dopo la somministrazione della dose di richiamo, effettuata dopo 28 giorni, perdurando per almeno 10 mesi. La cavia sembra essere un utile modello di laboratorio per la valutazione delle proprietà antigeniche dei vaccini contro la peste equina.
Vaccino inattivato e adiuvato per il controllo delle infezioni da sierotipo 9 del virus della peste equina: valutazione dell'efficacia in cavallo e cavia
Rossella Lelli,Umberto Molini,Gaetano Federico Ronchi,Emanuela Rossi
Veterinaria Italiana , 2013,
Abstract: La peste equina (PE) è una malattia virale non contagiosa dei solipedi trasmessa da insetti vettori appartenenti al genere Culicoides. La malattia è endemica in numerose regioni dell'Africa e passate esperienze hanno evidenziato come l'Italia sia un paese esposto alle malattie infettive emergenti, endemiche in Africa. Un'incursione del virus della PE unitamente alla presenza del vettore Culicoides potrebbero essere causa di una emergenza epidemica. Onderstepoort Biological Products (OBP) commercializza un vaccino vivo attenuato contenente 7 dei 9 sierotipi virali, i sierotipi 5 e 9 sono esclusi dal vaccino. L'uso di tali vaccini è controverso, pertanto, da diversi anni, vengono condotti studi su prodotti inattivati o ricombinanti. Poiché la ricerca sui vaccini PE è ostacolata dalla necessità di utilizzare il cavallo per la valutazione dell'immunogenicità, in un precedente esperimento è stata studiata la risposta sierologica ai sierotipi 5 e 9, in cavie e cavalli. Nelle due specie animali è stata osservata una risposta durevole e sovrapponibile. Nel presente studio sono state saggiate per un periodo di 12 mesi le risposte sierologiche ottenute in cavie e cavalli immunizzati con il vaccino inattivato formulato con il sierotipo 9. Le risposte sierologiche nelle due specie animali si sono confermate sovrapponibili. Al challenge dell'immunità i cavalli sono risultati protetti dall'infezione e dalla malattia.
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