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Search Results: 1 - 10 of 3670 matches for " Federico Maggi "
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Conceptual and mathematical modeling of insect-borne plant diseases: theory and application to flavescence doree in grapevine
Maggi Federico,Domenico Bosco,Cristina Marzachi'
Quantitative Biology , 2014,
Abstract: Insect-borne plant diseases recur commonly in wild plants and in agricultural crops, and are responsible for severe losses in terms of produce yield and monetary return. Mathematical models of insect-borne plant diseases are therefore an essential tool to help predicting the progression of an epidemic disease and aid in decision making when control strategies are to be implemented in the field. While retaining a generalized applicability of the proposed model to plant epidemics vectored by insects, we specifically investigated the epidemics of Flavescence dor\'ee phytoplasma (FD) in grapevine plant Vitis vinifera specifically transmitted by the leafhopper Scaphoideus titanus. The epidemiological model accounted for life-cycle stage of S. titanus, FD pathogen cycle within S. titanus and V. vinifera, vineyard setting, and agronomic practices. The model was comprehensively tested against biological S. titanus life cycle and FD epidemics data collected in various research sites in Piemonte, Italy, over multiple years. The work presented here represents a unique suite of governing equations tested on existing independent data and sets the basis for further modelling advances and possible applications to investigate effectiveness of real-case epidemics control strategies and scenarios.
Unusual Detection of Lathosterol in Amniotic Fluids Investigated for the Determination of Cholesterol and 7-Dehydrocholesterol for Suspected Smith-Lemli-Opitz Syndrome  [PDF]
Veniero Gambaro, Fiorenza Farè, Andrea Barlocco, Federico Maggi, Giuseppe Simoni, Lucia Dell’Acqua, Chiara Rusconi, Gabriella Roda
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.54031
Abstract: The Smith-Lemli-Opitz syndrome (SLOS), is an autosomal recessive disorder caused by a 7-dehydrocholesterol reductase deficiency, which is characterized by abnormally elevated amniotic fluid 7-DHC (7-dehydrocholesterol) concentrations. A GC/FID (gas-chromatography with a flame ionization detector) and GC/MS (gas-chromatography with a mass detector) method was optimized for the detection of cholesterol and 7-DHC in amniotic fluids. The quantitative determination of cholesterol in 39 control amniotic fluids evidenced that between the fourth and fifth month of pregnancy the levels of this analyte are quite constant, the concentration of total and free cholesterol being respectively 10.3 μg·mL﹣1 (SD = ±3.6) and 1.7 μg·mL﹣1 (SD = ±0.91), while the analysis of 60 amniotic fluids potentially related to SLOS, showed a higher variability of cholesterol levels. Moreover, in 13 samples an analyte which did not correspond either to cholesterol or to 7-DHC was detected. A GC/MS investigation allowed us to identify this compound as lathosterol, a precursor of cholesterol in the biosynthetic pathway.
A Particle-Water Based Model for Water Retention Hysteresis
Yixiang Gan,Federico Maggi,Giuseppe Buscarnera,Itai Einav
Physics , 2013, DOI: 10.1680/geolett.13.00046
Abstract: A particle-water discrete element based approach to describe water movement in partially saturated granular media is presented and tested. Water potential is governed by both capillary bridges, dominant at low saturations, and the pressure of entrapped air, dominant at high saturations. The approach captures the hysteresis of water retention during wetting and drainage by introducing the local evolution of liquid-solid contact angles at the level of pores and grains. Extensive comparisons against experimental data are presented. While these are made without the involvement of any fitting parameters, the method demonstrates relative high success by achieving a correlation coefficient of at least 82%, and mostly above 90%. For the tested materials with relatively mono-disperse grain size, the hysteresis of water retention during cycles of wetting and drainage has been shown to arise from the dynamics of solid-liquid contact angles as a function of local liquid volume changes.
Tracking and Characterizing Botnets Using Automatically Generated Domains
Stefano Schiavoni,Federico Maggi,Lorenzo Cavallaro,Stefano Zanero
Computer Science , 2013,
Abstract: Modern botnets rely on domain-generation algorithms (DGAs) to build resilient command-and-control infrastructures. Recent works focus on recognizing automatically generated domains (AGDs) from DNS traffic, which potentially allows to identify previously unknown AGDs to hinder or disrupt botnets' communication capabilities. The state-of-the-art approaches require to deploy low-level DNS sensors to access data whose collection poses practical and privacy issues, making their adoption problematic. We propose a mechanism that overcomes the above limitations by analyzing DNS traffic data through a combination of linguistic and IP-based features of suspicious domains. In this way, we are able to identify AGD names, characterize their DGAs and isolate logical groups of domains that represent the respective botnets. Moreover, our system enriches these groups with new, previously unknown AGD names, and produce novel knowledge about the evolving behavior of each tracked botnet. We used our system in real-world settings, to help researchers that requested intelligence on suspicious domains and were able to label them as belonging to the correct botnet automatically. Additionally, we ran an evaluation on 1,153,516 domains, including AGDs from both modern (e.g., Bamital) and traditional (e.g., Conficker, Torpig) botnets. Our approach correctly isolated families of AGDs that belonged to distinct DGAs, and set automatically generated from non-automatically generated domains apart in 94.8 percent of the cases.
PuppetDroid: A User-Centric UI Exerciser for Automatic Dynamic Analysis of Similar Android Applications
Andrea Gianazza,Federico Maggi,Aristide Fattori,Lorenzo Cavallaro,Stefano Zanero
Computer Science , 2014,
Abstract: Popularity and complexity of malicious mobile applications are rising, making their analysis difficult and labor intensive. Mobile application analysis is indeed inherently different from desktop application analysis: In the latter, the interaction of the user (i.e., victim) is crucial for the malware to correctly expose all its malicious behaviors. We propose a novel approach to analyze (malicious) mobile applications. The goal is to exercise the user interface (UI) of an Android application to effectively trigger malicious behaviors, automatically. Our key intuition is to record and reproduce the UI interactions of a potential victim of the malware, so as to stimulate the relevant behaviors during dynamic analysis. To make our approach scale, we automatically re-execute the recorded UI interactions on apps that are similar to the original ones. These characteristics make our system orthogonal and complementary to current dynamic analysis and UI-exercising approaches. We developed our approach and experimentally shown that our stimulation allows to reach a higher code coverage than automatic UI exercisers, so to unveil interesting malicious behaviors that are not exposed when using other approaches. Our approach is also suitable for crowdsourcing scenarios, which would push further the collection of new stimulation traces. This can potentially change the way we conduct dynamic analysis of (mobile) applications, from fully automatic only, to user-centric and collaborative too.
XSS Peeker: A Systematic Analysis of Cross-site Scripting Vulnerability Scanners
Enrico Bazzoli,Claudio Criscione,Federico Maggi,Stefano Zanero
Computer Science , 2014,
Abstract: Since the first publication of the "OWASP Top 10" (2004), cross-site scripting (XSS) vulnerabilities have always been among the top 5 web application security bugs. Black-box vulnerability scanners are widely used in the industry to reproduce (XSS) attacks automatically. In spite of the technical sophistication and advancement, previous work showed that black-box scanners miss a non-negligible portion of vulnerabilities, and report non-existing, non-exploitable or uninteresting vulnerabilities. Unfortunately, these results hold true even for XSS vulnerabilities, which are relatively simple to trigger if compared, for instance, to logic flaws. Black-box scanners have not been studied in depth on this vertical: knowing precisely how scanners try to detect XSS can provide useful insights to understand their limitations, to design better detection methods. In this paper, we present and discuss the results of a detailed and systematic study on 6 black-box web scanners (both proprietary and open source) that we conducted in coordination with the respective vendors. To this end, we developed an automated tool to (1) extract the payloads used by each scanner, (2) distill the "templates" that have originated each payload, (3) evaluate them according to quality indicators, and (4) perform a cross-scanner analysis. Unlike previous work, our testbed application, which contains a large set of XSS vulnerabilities, including DOM XSS, was gradually retrofitted to accomodate for the payloads that triggered no vulnerabilities. Our analysis reveals a highly fragmented scenario. Scanners exhibit a wide variety of distinct payloads, a non-uniform approach to fuzzing and mutating the payloads, and a very diverse detection effectiveness.
Projection of compact fractal sets: application to diffusion-limited and cluster-cluster aggregates
F. Maggi
Nonlinear Processes in Geophysics (NPG) , 2008,
Abstract: The need to assess the three-dimensional fractal dimension of fractal aggregates from the fractal dimension of two-dimensional projections is very frequent in geophysics, soil, and atmospheric sciences. However, a generally valid approach to relate the two- and three-dimensional fractal dimensions is missing, thus questioning the accuracy of the method used until now in practical applications. A mathematical approach developed for application to suspended aggregates made of cohesive sediment is investigated and applied here more generally to Diffusion-Limited Aggregates (DLA) and Cluster-Cluster Aggregates (CCA), showing higher accuracy in determining the three-dimensional fractal dimension compared to the method currently used.
Il rapporto d'indicazione nella ricerca visuale
Giorgio Maggi
m@gm@ , 2009,
Abstract: Cosa cambia nella progettazione di un piano della ricerca quando introduciamo l'elemento-dato visuale come materiale empirico fondamentale su cui ruota l'indagine scientifico-sociale? Più specificatamente cosa cambia nel rapporto d'indicazione quando ad essere collegate al concetto generale sono delle immagini-indicatori? In questo articolo tenterò di rispondere a questo non semplice interrogativo sostenendo la tesi che nella ricerca visuale si compie, necessariamente, una semplificazione logico-semantica o meglio un accorpamento delle fasi logico-procedurali che intercorrono nel classico processo di scomposizione dei concetti teorici in referenti empirici.
I treni e l’unificazione d’Italia: l’epoca delle costruzioni ferroviarie Trains and the Italian Unification: the Time of the Railways Buildings
Stefano Maggi
TeMA : Journal of Land Use, Mobility and Environment , 2011, DOI: 10.6092/1970-9870/224
Abstract: Se si rileggono i testi dei patrioti del Risorgimento, si trovano frequenti accenni alle “strade ferrate”, come allora si chiamavano, ritenute indispensabili per collegare gli Italiani, divisi fra i diversi Stati preunitari. Abolizione dei dazi, libertà del commercio, circolazione delle idee furono associati all’idea di nazione italiana, trovando la realizzazione “fisica” nelle ferrovie, che dovevano unire il territorio della penisola dalle Alpi alla Puglia e alla Calabria. Al momento dell’unità d’Italia, non esisteva una rete ferroviaria nazionale, sebbene il Piemonte di Cavour avesse sviluppato un cospicuo reticolo di strade ferrate, che misuravano 850 km. Seguivano, per l’estensione dei binari, il Lombardo-Veneto con 607 km, il Granducato di Toscana con 323 km, lo Stato Pontificio con 132 km, il Regno delle Due Sicilie con 128 km, il Ducato di Parma con 99 km, il Ducato di Modena con 50 km. Molti tratti erano in corso di costruzione, ma non si aveva una rete interstatale, perché gli Stati preunitari avevano operato separatamente l’uno dall’altro. Con l’eccezione della tratta da Torino a Bologna, in corso di completamanto nel 1860, per il resto le reti erano state pensate per servizi interni a ciascuno Stato. Per mettere in comunicazione gli Italiani delle diverse regioni e creare un mercato nazionale, i governi post-unitari dedicarono dunque alle ferrovie i maggiori investimenti per lavori pubblici. Nell’arco di un decennio, si completò l’ossatura fondamentale della rete, con 6.600 km nel 1871, anno in cui fu anche inaugurata la galleria del Fréjus di 13,6 km, la più lunga del mondo, che poneva l’Italia sulla rotta della “Valigia delle Indie”, il più intenso traffico mondiale di merci fra l’Inghilterra e la popolosa colonia delle Indie britanniche. Negli anni ’70 furono estesi i collegamenti e nel 1879 fu approvata la legge sulle ferrovie complementari - destinate a completare la rete della penisola e delle isole maggiori - che aprì un cinquantennio di costruzione di ferrovie secondarie, con la ramificazione della rete. Allo stesso tempo, fu estesa la rete delle strade ordinarie, che dovevano servire soprattutto a collegare i centri minori con le stazioni ferroviarie, trasformando le mulattiere in carreggiabili. The physical construction of modern Italy began in 1861, with the foundation of the Kingdom of Italy. The historical period coincided with the early industrial development of north-western Italy, and so the new infrastructure system developed in response, on the one hand, to the need to join together all the fragmentary pieces that formed th
T. A. Sebeok e i congegni di modellazione del mondo: strumenti teorici al servizio delle pratiche professionali
Giorgio Maggi
m@gm@ , 2005,
Abstract: L'elaborato si compone di una parte che comprende l'illustrazione delle linee generali del pensiero teorico di T. A. Sebeok e nello specif ico della sua teoria dei "sistemi di modellazione", e l'altra che include le riflessioni circa la possibilità di adoperare l'approccio biosemiotico alla realtà sociale e costruire, in tale direzione, un professionalismo ideal-tipico che sia capace di rispondere alle esigenze pratiche della vita quotidiana.
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