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Search Results: 1 - 10 of 8228 matches for " Francesca Luca? "
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Current identification in vacuum circuit breakers as a least squares problem*
Ghezzi Luca,Rapetti Francesca
ESAIM : Proceedings , 2013, DOI: 10.1051/proc/201238020
Abstract: In this work, a magnetostatic inverse problem is solved, in order to reconstruct the electric current distribution inside high voltage, vacuum circuit breakers from measurements of the outside magnetic field. The (rectangular) final algebraic linear system is solved in the least square sense, by involving a regularized singular value decomposition of the system matrix. An approximated distribution of the electric current is thus returned, without the theoretical problem which is encountered with optical methods of matching light to temperature and finally to current density. The feasibility is justified from the computational point of view as the (industrial) goal is to evaluate whether, or to what extent in terms of accuracy, a given experimental set-up (number and noise level of sensors) is adequate to work as a “magnetic camera” for a given circuit breaker. Dans cet article, on résout un problème inverse magnétostatique pour déterminer la distribution du courant électrique dans le vide d’un disjoncteur à haute tension à partir des mesures du champ magnétique extérieur. Le système algébrique (rectangulaire) final est résolu au sens des moindres carrés en faisant appel à une décomposition en valeurs singulières regularisée de la matrice du système. On obtient ainsi une approximation de la distribution du courant électrique sans le problème théorique propre des méthodes optiques qui est celui de relier la lumière à la température et donc à la densité du courant. La faisabilité est justifiée d’un point de vue numérique car le but (industriel) est d’évaluer si, ou à quelle précision, un dispositif expérimental donné (nombre et seuil limite de bruit des senseurs) peut travailler comme une “caméra magnétique” pour un certain disjoncteur.
Staphylococcus haemolyticus superinfection of legionella pneumonia during infliximab therapy  [PDF]
Marianna Porzio, Luca Valenti, Daniela Bignamini, Francesca Ricchini, Alessandro Palleschi, Paolo Tarsia, Silvia Fargion
Open Journal of Internal Medicine (OJIM) , 2011, DOI: 10.4236/ojim.2011.11003
Abstract: We present the case of a 42-year-old man affected by psoriasis with Staphylococcus Haemolyticus superin-fection of Legionella pneumonia during infliximab therapy. The introduction of compounds that block TNF-α has yielded great benefits for patients affected by selected autoimmune diseases that fail to respond to classic anti-inflammatory agents, but, on the other hand, has led to an increased susceptibility to infec-tions, in particular of those caused by intracellular pathogens, such as L. Pneumophila. Emerging evi-dence suggests that legionellosis can be complicated by superinfection with other agents, including sap-rophytic microorganisms, among which coagulase- negative staphylococci. To our knowledge, this is the first report of systemic legionellosis with superinfec-tion by S. Haemolyticus, an emerging nosocomial multi-resistant pathogen that commonly causes sep-ticemia, osteomyelitis or endocarditis, but has not so far been associated with necrotizing pneumonia. De-spite the optimal antimicrobial therapy for Staphylo-coccus spp. pneumonia is still controversial, evidence suggests that in patients with confirmed positivity for methicillin resistant strains, particularly if sensitivity to vancomycin is suboptimal, linezolid should be the first choice therapy, being superior to vancomycin and teicoplanin.
Neural Network Emulation of the Integral Equation Model with Multiple Scattering
Luca Pulvirenti,Francesca Ticconi,Nazzareno Pierdicca
Sensors , 2009, DOI: 10.3390/s91008109
Abstract: The Integral Equation Model with multiple scattering (IEMM) represents a well-established method that provides a theoretical framework for the scattering of electromagnetic waves from rough surfaces. A critical aspect is the long computational time required to run such a complex model. To deal with this problem, a neural network technique is proposed in this work. In particular, we have adopted neural networks to reproduce the backscattering coefficients predicted by IEMM at L- and C-bands, thus making reference to presently operative satellite radar sensors, i.e., that aboard ERS-2, ASAR on board ENVISAT (C-band), and PALSAR aboard ALOS (L-band). The neural network-based model has been designed for radar observations of both flat and tilted surfaces, in order to make it applicable for hilly terrains too. The assessment of the proposed approach has been carried out by comparing neural network-derived backscattering coefficients with IEMM-derived ones. Different databases with respect to those employed to train the networks have been used for this purpose. The outcomes seem to prove the feasibility of relying on a neural network approach to efficiently and reliably approximate an electromagnetic model of surface scattering.
On two closely related species of Xiphinema americanum-group: X. simile Lamberti, Choleva & Agostinelli, 1983 and X. parasimile Barsi & Lamberti, 2004 (Longidoridae), with a description of the male of X. parasimile
Stela Lazarova,Francesca De Luca,Vlada Peneva
ZooKeys , 2008, DOI: 10.3897/zookeys.3.26
Abstract: Several populations of Xiphinema simile Lamberti, Choleva & Agostinelli, 1983 and two of X. parasimile Barsi & Lamberti, 2004, originating from various habitats – natural and man-made, have been studied. Xiphinema simile was associated both with cultivated and naturally growing plants, while X. parasimile was recovered from soil around grapevine. Data on the morphological and biometrical characteristics (including juvenile stages) are presented and variations discussed. Pharyngeal bulbus and glandularium length, vaginal and uterine characteristics were shown to be good differentiating characters. Present report of X. parasimile is a new record for Bulgaria as well as a new plant association for the species. The description of its male is provided for the first time. The Bulgarian population of X. parasimile showed the same pattern as the Serbian population revealed by the RFLP analyses of D1-D2 region.
Burst Format Design for Optimum Joint Estimation of Doppler-Shift and Doppler-Rate in Packet Satellite Communications
Giugno Luca,Zanier Francesca,Luise Marco
EURASIP Journal on Wireless Communications and Networking , 2007,
Abstract: This paper considers the problem of optimizing the burst format of packet transmission to perform enhanced-accuracy estimation of Doppler-shift and Doppler-rate of the carrier of the received signal, due to relative motion between the transmitter and the receiver. Two novel burst formats that minimize the Doppler-shift and the Doppler-rate Cramér-Rao bounds (CRBs) for the joint estimation of carrier phase/Doppler-shift and of the Doppler-rate are derived, and a data-aided (DA) estimation algorithm suitable for each optimal burst format is presented. Performance of the newly derived estimators is evaluated by analysis and by simulation, showing that such algorithms attain their relevant CRBs with very low complexity, so that they can be directly embedded into new-generation digital modems for satellite communications at low SNR.
Burst Format Design for Optimum Joint Estimation of Doppler-Shift and Doppler-Rate in Packet Satellite Communications
Luca Giugno,Francesca Zanier,Marco Luise
EURASIP Journal on Wireless Communications and Networking , 2007, DOI: 10.1155/2007/29086
Abstract: This paper considers the problem of optimizing the burst format of packet transmission to perform enhanced-accuracy estimation of Doppler-shift and Doppler-rate of the carrier of the received signal, due to relative motion between the transmitter and the receiver. Two novel burst formats that minimize the Doppler-shift and the Doppler-rate Cram r-Rao bounds (CRBs) for the joint estimation of carrier phase/Doppler-shift and of the Doppler-rate are derived, and a data-aided (DA) estimation algorithm suitable for each optimal burst format is presented. Performance of the newly derived estimators is evaluated by analysis and by simulation, showing that such algorithms attain their relevant CRBs with very low complexity, so that they can be directly embedded into new-generation digital modems for satellite communications at low SNR.
5′ UTR Control of Native ERG and of Tmprss2:ERG Variants Activity in Prostate Cancer
Francesca Zammarchi, George Boutsalis, Luca Cartegni
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0049721
Abstract: ERG, a member of the ETS transcription factor family, is frequently overexpressed in prostate cancer as a result of its fusion to the androgen-responsive Tmprss2 gene. Different genomic rearrangements and alternative splicing events around the junction region lead to multiple combination of Tmprss2:ERG fusion transcripts that correlate with different tumor aggressiveness, but their specific functions and biological activities are still unclear. The complexity of ERG expression pattern is compounded by the use of alternative promoters, splice sites, polyadenylation sites and translation initiation sites in both the native and fusion contexts. Our systematic characterization of native ERG and Tmprss2:ERG variants reveals that their different oncogenic potential is impacted by the status of the Ets domain and the configuration of the 5′ UTR region. In particular, expression and activity of functional ERG and Tmprss2:ERG variants are influenced both by translation initiation signals within the different isoforms and by inhibitory upstream Open Reading Frames (uORF) in their 5′ UTRs. Stable expression of ERG and Tmprss2:ERG variants promoted cell migration/invasion, induced a block of proliferation and induced a senescence-like state, suggesting a role for these variants in the prostate tumorigenesis process. In addition to Tmprss2:ERG fusion products, a group of related native ERG isoforms is also highly over-expressed in fusion-carrying prostate cancers, and share the same translation initiation site (in ERG exon 4) with the commonly observed Tmprss2 exon1 joined to ERG exon 4 (T1:E4) fusion-derived variant. Usage of this ATG can be preferentially down-regulated by directed antisense-based compounds, possibly representing the basis of a targeted approach that distinguishes between tumor–associated and normal ERG.
Epidemiological, Pathophysiological and Clinical Peculiarities of Graves’ Disease in Children with Down and Turner Syndrome: A Literature Review  [PDF]
Malgorzata Wasniewska, Tommaso Aversa, Filippo De Luca, Mariella Valenzise, Maria Francesca Messina, Fortunato Lombardo
Health (Health) , 2014, DOI: 10.4236/health.2014.612178
Abstract: Aim: to describe the salient relationships between Graves’ disease (GD) and both Turner syndrome (TS) and Down syndrome (DS). Design: to conduct a secondary analysis of current literature on this topic. Results: 1) the prevalences of GD in TS and in DS young patients are 1.7% and 6.5‰, respectively, i.e. higher than that in pediatric general population (around 1‰); 2) in both these chromosomopathies GD presentation is often preceded by Hashimoto’s thyroiditis (HT) antecedents; 3) in both TS and DS, GD presents with a clinical picture very similar to that observed in GD patients without these chromosomopathies; 4) in TS, clinical course of GD under pharmacological therapy is very similar to that observed in non-TS girls; 5) in DS, clinical course of GD under pharmacological therapy is less severe than that in non-DS patients. Conclusions: in the children with either TS or DS, GD is characterized by two common epidemiological peculiarities, i.e. increased prevalence rate and elevated frequency of HT antecedents.
Structural stability and uniformity of magnetic Pt13 nanoparticles in NaY zeolite
Luca Pavan,Cono Di Paola,Francesca Baletto
Physics , 2015,
Abstract: Based on first-principles simulations, the structural stability and magnetic uniformity of Pt13 nanoparticles encapsulated in a NaY zeolite were investigated. Among 50 stable isomers in the gas phase, only 15 could be accommodated into a zeolite pore and severe structural rearrangements occured depending on whether the solid angle at the Pt vertex bound to the supercage was larger than 2 sr (i.e. icosahedron). When van der Waals forces were included, the global minimum was found to be a new L-shaped cubic wire that is unstable in the gas phase. The total magnetization of the encapsulated Pt13 decreases due to the stabilization of less coordinated isomers, with the majority of clusters charaterized by a total magnetization of 2 {\mu}B, while the majority of free clusters exhibit a threefold value.
Static NLO susceptibilities: testing approximation schemes against exact results
Luca Del Freo,Francesca Terenziani,Anna Painelli
Physics , 2001, DOI: 10.1063/1.1426378
Abstract: The reliability of the approximations commonly adopted in the calculation of static optical (hyper)polarizabilities is tested against exact results obtained for an interesting toy-model. The model accounts for the principal features of typical nonlinear organic materials with mobile electrons strongly coupled to molecular vibrations. The approximations introduced in sum over states and finite field schemes are analyzed in detail. Both the Born-Oppenheimer and the clamped nucleus approximations turn out to be safe for molecules, whereas for donor-acceptor charge transfer complexes deviations from adiabaticity are expected. In the regime of low vibrational frequency, static susceptibilities are strongly dominated by the successive derivatives of the potential energy and large vibrational contributions to hyperpolarizabilities are found. In this regime anharmonic corrections to hyperpolarizabilities are very large, and the harmonic approximation, exact for the linear polarizability, turns out totally inadequate for nonlinear responses. With increasing phonon frequency the role of vibrations smoothly decreases, until, in the antiadiabatic (infinite vibrational frequency) regime, vibrations do not contribute anymore to static susceptibilities, and the purely electronic responses are regained.
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