428 research outputs found
Molecular detection of Rickettsia, Borrelia, and Babesia species in Ixodes ricinus sampled in northeastern, central, and insular areas of Italy.
The aim of the present study was to provide insight into the diversity of tick-borne pathogens circulating in Italy, carried/transmitted by Ixodes ricinus, one of the most abundant tick species in the country. A total of 447 specimens sampled in five areas of northeastern, central and insular Italy were analysed by polymerase chain reaction and sequencing for the presence of rickettsiae, borreliae and babesiae. Several rickettsial species of the spotted fever group of zoonotic concern and other zoonotic pathogens were found, such as Borrelia burgdorferi s.s., Borrelia afzelii, Borrelia garinii, and Babesia venatorum. These findings confirm a wide distribution of tick-borne bacterial and protozoan species in Italy, and highlight the sanitary importance of I. ricinus, often recorded as feeding on humans
Radio recombination lines from obscured quasars with the SKA
We explore the possibility of detecting hydrogen radio recombination lines
from 0 < z < 10 quasars. We compute the expected Hnalpha flux densities as a
function of absolute magnitude and redshift by considering (i) the range of
observed AGN spectral indices from UV to X-ray bands, (ii) secondary
ionizations from X-ray photons, and (iii) stimulated emission due to nonthermal
radiation. All these effects are important to determine the line fluxes. We
find that the combination of slopes: alpha_X,hard = -1.11, alpha_X,soft = -0.7,
alpha_EUV = -1.3, alpha_UV = -1.7, maximizes the expected flux, f_Hnalpha = 10
microJy for z = 7 quasars with M_AB = -27 in the n = 50 lines; allowed SED
variations produce variations by a factor of 3 around this value. Secondaries
boost the line intensity by a factor of 2 to 4, while stimulated emission in
high-z quasars with M_AB = -26 provides an extra boost to RRL flux observed at
nu = 1 GHz if recombinations arise in HII regions with T_e = 10^3-5 K, n_e =
10^3-5 cm^-3. We compute the sensitivity required for a 5sigma detection of
Hnalpha lines using the SKA, finding that the SKA-MID could detect sources with
M_AB < -27 (M_AB < -26) at z < 8 (z < 3) in less than 100 hrs of observing
time. These observations could open new paths to searches for obscured SMBH
progenitors, complementing X-ray, optical/IR and sub-mm surveys.Comment: 11 pages, 9 figures; to be published in Monthly Notices of the Royal
Astronomical Society Main Journa
A model-driven approach to survivability requirements assessment for critical systems
Survivability is a crucial property for those systems – such as critical infrastructures or military Command and Control Information Systems – that provide essential services, since the latter must be operational even when the system is compromised due to attack or faults. This article proposes a model-driven method and a tool –MASDES– to assess the survivability requirements of critical systems. The method exploits the use of (1) (mis)use case technique and UML profiling for the specification of the survivability requirements and (2) Petri nets and model checking techniques for the requirement assessment. A survivability assessment model is obtained from an improved specification of misuse cases, which encompasses essential services, threats and survivability strategies. The survivability assessment model is then converted into a Petri net model for verifying survivability properties through model checking. The MASDES tool has been developed within the Eclipse workbench and relies on Papyrus tool for UML. It consists of a set of plug-ins that enable (1) to create a survivability system view using UML and profiling techniques and (2) to verify survivability properties. In particular, the tool performs model transformations in two steps. First, a model-to-model transformation generates, from the survivability view, a Petri net model and properties to be checked in a tool-independent format. Second, model-to-text transformations produce the Petri net specifications for the model checkers. A military Command and Control Information Systems has been used as a case study to apply the method and to evaluate the MASDES tool, within an iterative-incremental software development process
Modelling Security of Critical Infrastructures: A Survivability Assessment
Critical infrastructures, usually designed to handle disruptions caused by human errors or random acts of nature, define assets whose normal operation must be guaranteed to maintain its essential services for human daily living. Malicious intended attacks to these targets need to be considered during system design. To face these situations, defence plans must be developed in advance. In this paper, we present a Unified Modelling Language profile, named SecAM, that enables the modelling and security specification for critical infrastructures during the early phases (requirements, design) of system development life cycle. SecAM enables security assessment, through survivability analysis, of different security solutions before system deployment. As a case study, we evaluate the survivability of the Saudi Arabia crude-oil network under two different attack scenarios. The stochastic analysis, carried out with Generalized Stochastic Petri nets, quantitatively estimates the minimization of attack damages on the crude-oil network
Using Process Mining and Model-driven Engineering to Enhance Security of Web Information Systems
Due to the development of Smart Cities and Internet of Things, there has been an increasing interest in the use of Web information systems in different areas and domains. Besides, the number of attacks received by this kind of systems is increasing continuously. Therefore, there is a need to strengthen their protection and security. In this paper, we propose a method based on Process Mining and Model- Driven Engineering to improve the security of Web information systems. Besides, this method has been applied to the SID Digital Library case study and some preliminary results to improve the security of this system are described
An approach for the automatic verification of blockchain protocols: the Tweetchain case study
This paper proposes a model-driven approach for the security modelling and analysis of blockchain based protocols. The modelling is built upon the definition of a UML profile, which is able to capture transaction-oriented information. The analysis is based on existing formal analysis tools. In particular, the paper considers the Tweetchain protocol, a recent proposal that leverages online social networks, i.e., Twitter, for extending blockchain to domains with small-value transactions, such as IoT. A specialized textual notation is added to the UML profile to capture features of this protocol. Furthermore, a model transformation is defined to generate a Tamarin model, from the UML models, via an intermediate well-known notation, i.e., the Alice &Bob notation. Finally, Tamarin Prover is used to verify the model of the protocol against some security properties. This work extends a previous one, where the Tamarin formal models were generated by hand. A comparison on the analysis results, both under the functional and non-functional aspects, is reported here too
How Board Gender Diversity Affects Corporate Reputation: A Study on Italian Most Reputable Companies
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