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Search Results: 1 - 10 of 18538 matches for " Alberto Niccolini "
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Onset Time Determination of Acoustic and Electromagnetic Emission During Rock Fracture
Gianni Niccolini;Jie Xu;Amedeo Manuello;Giuseppe Lacidogna;Alberto Carpinteri
PIER Letters , 2012, DOI: 10.2528/PIERL12070203
Abstract: We present an application of the Akaike Information Criterion () for an automatic and accurate determination of the acoustic and electromagnetic emission (AE and EME) onset times. The onset time information is used to derive the time delays between correlated AE and EME events from rock specimens during laboratory fracture experiments. The observed correlation in time between AE and EME events is consistent with EME release during microcrack growth. Relevant load drops are accompanied by AE bursts, expected to be generated during macrocracks propagation.
A Proteomic Investigation of Soluble Olfactory Proteins in Anopheles gambiae
Guido Mastrobuoni, Huili Qiao, Immacolata Iovinella, Simona Sagona, Alberto Niccolini, Francesca Boscaro, Beniamino Caputo, Marta R. Orejuela, Alessandra della Torre, Stefan Kempa, Antonio Felicioli, Paolo Pelosi, Gloriano Moneti, Francesca Romana Dani
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0075162
Abstract: Odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) are small soluble polypeptides that bind semiochemicals in the lymph of insect chemosensilla. In the genome of Anopheles gambiae, 66 genes encode OBPs and 8 encode CSPs. Here we monitored their expression through classical proteomics (2D gel-MS analysis) and a shotgun approach. The latter method proved much more sensitive and therefore more suitable for tiny biological samples as mosquitoes antennae and eggs. Females express a larger number and higher quantities of OBPs in their antennae than males (24 vs 19). OBP9 is the most abundant in the antennae of both sexes, as well as in larvae, pupae and eggs. Of the 8 CSPs, 4 were detected in antennae, while SAP3 was the only one expressed in larvae. Our proteomic results are in fairly good agreement with data of RNA expression reported in the literature, except for OBP4 and OBP5, that we could not identify in our analysis, nor could we detect in Western Blot experiments. The relatively limited number of soluble olfactory proteins expressed at relatively high levels in mosquitoes makes further studies on the coding of chemical messages at the OBP level more accessible, providing for few specific targets. Identification of such proteins in Anopheles gambiae might facilitate future studies on host finding behavior in this important disease vector.
BG-12 and its potential for the prevention of relapse in multiple sclerosis
Giannetti P, Niccolini F, Nicholas R
Degenerative Neurological and Neuromuscular Disease , 2012, DOI: http://dx.doi.org/10.2147/DNND.S35790
Abstract: G-12 and its potential for the prevention of relapse in multiple sclerosis Review (1265) Total Article Views Authors: Giannetti P, Niccolini F, Nicholas R Published Date October 2012 Volume 2012:2 Pages 119 - 132 DOI: http://dx.doi.org/10.2147/DNND.S35790 Received: 10 July 2012 Accepted: 28 August 2012 Published: 01 October 2012 Paolo Giannetti,1 Flavia Niccolini,2 Richard Nicholas1 1Centre for Neurosciences, Division of Experimental Medicine, Department of Medicine, Imperial College, London, UK; 2University of Rome “Sapienza”, Department of Neurology and Psychiatry, Rome, Italy Abstract: Multiple sclerosis (MS) arises from an immune attack on the central nervous system producing demyelination and axonal loss. Clinically the relapsing–remitting course is characterized by subacute onset of neurological symptoms usually with partial or complete recovery, while the progressive course, predominant in the later stages, is characterized by progressive disability in the absence of relapses. A number of disease-modifying treatments have been developed and are increasingly effective at targeting relapses. Early injectable therapies such as interferon and glatiramer acetate are only partially effective, but have a good safety record. Recently, natalizumab, an intravenous therapy, demonstrated increased effectiveness, but side effects complicate its use. The first oral therapy offering good efficacy and convenience, fingolimod, was approved in USA in 2010 and Europe in 2011. BG-12 is a potential novel oral therapy for MS, which has previously been used as a different formulation for psoriasis. It has anti-inflammatory and neuroprotective actions in vitro, which makes it a promising candidate for future therapies. Phase II studies showed that BG-12 reduced MRI inflammatory activity over placebo, which was confirmed in two Phase III studies indicating immune modulation may be its principal action rather than neuroprotection. In these studies, BG-12 reduced relapse rates consistently with variable effects on progression and few serious adverse events. With its favorable efficacy–tolerability profile, BG-12 could offer a substantial step forward for the care for subjects affected by relapsing MS.
Classification of poplar stand areas by high-resolution satellite images
Grignetti A,Coaloa D,Niccolini G
Forest@ , 2009, DOI: 10.3832/efor0590-006
Abstract: This work concerns the classification of different crown cover classes of Poplar stands, using high spatial resolution images (Ikonos and Quickbird satellites), in order to provide poplar monitoring. The test sites are two agricultural areas, located in the alluvial plain of northern Italy, close to Alessandria. In order to enhance spectral differences among classes, textural and high-pass filters were applied and vegetation indices (ratio, difference and normalized difference) were processed. Images were then classified by means of an object-oriented approach which include a segmentation process followed by the application of a Standard Nearest Neighbor classifier on different data sets of spectral images (mean and standard deviation images) and shape indices (shape, compactness). The data sets were defined using the Feature Space Optimization tool available in the Definiens Developer7 software. From a set of attributes, this tool selects the best combination that produces the largest separability among the classes. The shape of the polygons matched the agricultural plots and the classification results were compared with the reference map defined by means of aerial photo interpretation and ground surveys. New poplar classes were defined in order to improve classification results. The accuracy values obtained were satisfactory (close to 73% for Ikonos and 82% for Quickbird images) and they constitute a basis for automated recognition of poplar plantations and for updating poplar stands assessments.
Acoustic emission monitoring of medieval towers considered as sensitive earthquake receptors
A. Carpinteri,G. Lacidogna,G. Niccolini
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2007,
Abstract: Many ancient masonry towers are present in Italian territory. In some cases these structures are at risk on account of the intensity of the stresses they are subjected to due to the high level of regional seismicity. In order to preserve this inestimable cultural heritage, a sound safety assessment should take into account the evolution of damage phenomena. In this connection, acoustic emission (AE) monitoring can be highly effective. This study concerns the structural stability of three medieval towers rising in the centre of Alba, a characteristic town in Piedmont (Italy). During the monitoring period a correlation between peaks of AE activity in the masonry of these towers and regional seismicity was found. Earthquakes always affect structural stability. Besides that, the towers behaved as sensitive earthquake receptors. Here a method to correlate bursts of AE activity in a masonry building and regional seismicity is proposed. In particular, this method permits to identify the premonitory signals that precede a catastrophic event on a structure, since, in most cases, these warning signs can be captured well in advance.
BG-12 and its potential for the prevention of relapse in multiple sclerosis
Giannetti P,Niccolini F,Nicholas R
Degenerative Neurological and Neuromuscular Disease , 2012,
Abstract: Paolo Giannetti,1 Flavia Niccolini,2 Richard Nicholas11Centre for Neurosciences, Division of Experimental Medicine, Department of Medicine, Imperial College, London, UK; 2University of Rome “Sapienza”, Department of Neurology and Psychiatry, Rome, ItalyAbstract: Multiple sclerosis (MS) arises from an immune attack on the central nervous system producing demyelination and axonal loss. Clinically the relapsing–remitting course is characterized by subacute onset of neurological symptoms usually with partial or complete recovery, while the progressive course, predominant in the later stages, is characterized by progressive disability in the absence of relapses. A number of disease-modifying treatments have been developed and are increasingly effective at targeting relapses. Early injectable therapies such as interferon and glatiramer acetate are only partially effective, but have a good safety record. Recently, natalizumab, an intravenous therapy, demonstrated increased effectiveness, but side effects complicate its use. The first oral therapy offering good efficacy and convenience, fingolimod, was approved in USA in 2010 and Europe in 2011. BG-12 is a potential novel oral therapy for MS, which has previously been used as a different formulation for psoriasis. It has anti-inflammatory and neuroprotective actions in vitro, which makes it a promising candidate for future therapies. Phase II studies showed that BG-12 reduced MRI inflammatory activity over placebo, which was confirmed in two Phase III studies indicating immune modulation may be its principal action rather than neuroprotection. In these studies, BG-12 reduced relapse rates consistently with variable effects on progression and few serious adverse events. With its favorable efficacy–tolerability profile, BG-12 could offer a substantial step forward for the care for subjects affected by relapsing MS.Keywords: BG-12, multiple sclerosis, relapses, oral treatments
Cooperative Control for Multiple Autonomous Vehicles Using Descriptor Functions
Marta Niccolini,Lorenzo Pollini,Mario Innocenti
Journal of Sensor and Actuator Networks , 2014, DOI: 10.3390/jsan3010026
Abstract: The paper presents a novel methodology for the control management of a swarm of autonomous vehicles. The vehicles, or agents, may have different skills, and be employed for different missions. The methodology is based on the definition of descriptor functions that model the capabilities of the single agent and each task or mission. The swarm motion is controlled by minimizing a suitable norm of the error between agents’ descriptor functions and other descriptor functions which models the entire mission. The validity of the proposed technique is tested via numerical simulation, using different task assignment scenarios.
Fast ray-tracing algorithm for circumstellar structures (FRACS) I. Algorithm description and parameter-space study for mid-IR interferometry of B[e] stars
Gilles Niccolini,Philippe Bendjoya,Armando Domiciano De Souza
Physics , 2010, DOI: 10.1051/0004-6361/201014511
Abstract: The physical interpretation of spectro-interferometric data is strongly model-dependent. On one hand, models involving elaborate radiative transfer solvers are too time consuming in general to perform an automatic fitting procedure and derive astrophysical quantities and their related errors. On the other hand, using simple geometrical models does not give sufficient insights into the physics of the object. We propose to stand in between these two extreme approaches by using a physical but still simple parameterised model for the object under consideration. Based on this philosophy, we developed a numerical tool optimised for mid-infrared (mid-IR) interferometry, the fast ray-tracing algorithm for circumstellar structures (FRACS) which can be used as a stand-alone model, or as an aid for a more advanced physical description or even for elaborating observation strategies. FRACS is based on the ray-tracing technique without scattering, but supplemented with the use of quadtree meshes and the full symmetries of the axisymmetrical problem to significantly decrease the necessary computing time to obtain e.g. monochromatic images and visibilities. We applied FRACS in a theoretical study of the dusty circumstellar environments (CSEs) of B[e] supergiants (sgB[e]) in order to determine which information (physical parameters) can be retrieved from present mid-IR interferometry (flux and visibility). From a set of selected dusty CSE models typical of sgB[e] stars we show that together with the geometrical parameters (position angle, inclination, inner radius), the temperature structure (inner dust temperature and gradient) can be well constrained by the mid-IR data alone. Our results also indicate that the determination of the parameters characterising the CSE density structure is more challenging but, in some cases, upper limits as well as correlations on the parameters characterising the mass loss can be obtained. Good constraints for the sgB[e] central continuum emission (central star and inner gas emissions) can be obtained whenever its contribution to the total mid-IR flux is only as high as a few percents. Ray-tracing parameterised models such as FRACS are thus well adapted to prepare and/or interpret long wavelengths (from mid-IR to radio) observations at present (e.g. VLTI/MIDI) and near-future (e.g. VLTI/MATISSE, ALMA) interferometers.
Analyzing the Performance of LRU Caches under Non-Stationary Traffic Patterns
Mohamed Ahmed,Stefano Traverso,Paolo Giaccone,Emilio Leonardi,Saverio Niccolini
Computer Science , 2013,
Abstract: This work presents, to the best of our knowledge of the literature, the first analytic model to address the performance of an LRU (Least Recently Used) implementing cache under non-stationary traffic conditions, i.e., when the popularity of content evolves with time. We validate the accuracy of the model using Monte Carlo simulations. We show that the model is capable of accurately estimating the cache hit probability, when the popularity of content is non-stationary. We find that there exists a dependency between the performance of an LRU implementing cache and i) the lifetime of content in a system, ii) the volume of requests associated with it, iii) the distribution of content request volumes and iv) the shape of the popularity profile over time.
Temporal Locality in Today's Content Caching: Why it Matters and How to Model it
Mohamed Ahmed,Stefano Traverso,Michele Garetto,Paolo Giaccone,Emilio Leonardi,Saverio Niccolini
Computer Science , 2013,
Abstract: The dimensioning of caching systems represents a difficult task in the design of infrastructures for content distribution in the current Internet. This paper addresses the problem of defining a realistic arrival process for the content requests generated by users, due its critical importance for both analytical and simulative evaluations of the performance of caching systems. First, with the aid of YouTube traces collected inside operational residential networks, we identify the characteristics of real traffic that need to be considered or can be safely neglected in order to accurately predict the performance of a cache. Second, we propose a new parsimonious traffic model, named the Shot Noise Model (SNM), that enables users to natively capture the dynamics of content popularity, whilst still being sufficiently simple to be employed effectively for both analytical and scalable simulative studies of caching systems. Finally, our results show that the SNM presents a much better solution to account for the temporal locality observed in real traffic compared to existing approaches.
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