Closing the loop of SIEM analysis to Secure Critical Infrastructures

Critical Infrastructure Protection is one of the main challenges of last years. Security Information and Event Management (SIEM) systems are widely used for coping with this challenge. However, they currently present several limitations that have to be overcome. In this paper we propose an enhanced SIEM system in which we have introduced novel components to i) enable multiple layer data analysis; ii) resolve conflicts among security policies, and discover unauthorized data paths in such a way to be able to reconfigure network devices. Furthermore, the system is enriched by a Resilient Event Storage that ensures integrity and unforgeability of events stored.Comment: EDCC-2014, BIG4CIP-2014, Security Information and Event Management, Decision Support System, Hydroelectric Da

Ottimizzazione della produzione di polisaccaridi e lipidi nella diatomea marina Phaeodactylum tricornutum in coltura

Il lavoro sperimentale di questa tesi è stato condotto sulla coltivazione della diatomea Phaeodactylum tricornutum che grazie alla sua capacità di sintetizzare e di accumulare una elevata quantità di acidi grassi polinsaturi (PUFAs) ω-3 tra cui l’acido eicosapentanoico (EPA), ha un notevole interesse commerciale per la nutrizione umana. Il lavoro di tesi è stato svolto presso il Laboratorio di Biologia delle Alghe in due fasi sperimentali, nella prima, l’alga è stata coltivata usando un medium standard con due diversi rapporti molari N/P, valutando l’effetto della somministrazione di 1mg L-1 al giorno di CO2 sulla velocità di crescita e sulla composizione percentuale in termini di proteine polisaccaridi e lipidi della biomassa raccolta in fase stazionaria. I risultati ottenuti hanno mostrato che la somministrazione di CO2 durante la crescita dell’alga, determina un significativo incremento della biomassa algale ottenuta e una produzione maggiore di lipidi e polisaccaridi per cellula. Nella seconda fase sperimentale P.tricornutum è stata coltivata usando un refluo industriale con lo scopo di valutare la capacità dell’alga di rimozione dei componenti azotati e del fosforo per effettuare un processo di fitodepurazione e ridurre i costi dovuti all’impiego dei nutrienti nella coltivazione. I risultati ottenuti dimostrano che nel refluo l’alga presenta una velocità di crescita più elevata rispetto alle condizioni precedenti e, dopo la somministrazione di CO2, accumula una percentuale maggiore di proteine e di acidi grassi. In conclusione questi dati suggeriscono che l’utilizzo di un refluo industriale con la concomitante aggiunta di CO2 in basse concentrazioni nella coltivazione delle microalghe potrebbe ridurre i costi di produzione della biomassa su larga scala e consentirebbe di ottenere biomassa algale con un maggior valore commerciale

RR Lyrae stars as standard candles and stellar population tracers with Gaia

The main goal of this thesis is to exploit the dual role of RRLs as stellar population tracers in our Galaxy and its LG companions, and primary standard candles for the definition of the cosmic distance ladder, to (i) investigate the stellar populations in a number of new stellar satellites recently discovered around the Milky Way (MW) and Andromeda (M31) spiral galaxies; and (ii) study the luminosity - metallicity and period - luminosity - (metallicity) relations that RRLs conform to, based on the unprecedented astrometric and photometric dataset that is being collected by the European Space Agency (ESA) mission Gaia. The thesis is organized in 5 Chapters and 3 Appendices

Variable stars in the ultra-faint dwarf spheroidal galaxy Ursa Major I

We have performed the first study of the variable star population of Ursa Major I (UMa I), an ultra-faint dwarf satellite recently discovered around the Milky Way by the Sloan Digital Sky Survey. Combining time series observations in the B and V bands from four different telescopes, we have identified seven RR Lyrae stars in UMa I, of which five are fundamental-mode (RRab) and two are first-overtone pulsators (RRc). Our V, B-V color-magnitude diagram of UMa I reaches V~23 mag (at a signal-to-noise ratio of ~ 6) and shows features typical of a single old stellar population. The mean pulsation period of the RRab stars = 0.628, {\sigma} = 0.071 days (or = 0.599, {\sigma} = 0.032 days, if V4, the longest period and brightest variable, is discarded) and the position on the period-amplitude diagram suggest an Oosterhoff-intermediate classification for the galaxy. The RR Lyrae stars trace the galaxy horizontal branch at an average apparent magnitude of = 20.43 +/- 0.02 mag (average on 6 stars and discarding V4), giving in turn a distance modulus for UMa I of (m-M)0 = 19.94 +/- 0.13 mag, distance d= 97.3 +6.0/-5.7 kpc, in the scale where the distance modulus of the Large Magellanic Cloud is 18.5 +/- 0.1 mag. Isodensity contours of UMa I red giants and horizontal branch stars (including the RR Lyrae stars identified in this study) show that the galaxy has an S-shaped structure, which is likely caused by the tidal interaction with the Milky Way. Photometric metallicities were derived for six of the UMa I RR Lyrae stars from the parameters of the Fourier decomposition of the V-band light curves, leading to an average metal abundance of [Fe/H] = -2.29 dex ({\sigma} = 0.06 dex, average on 6 stars) on the Carretta et al. metallicity scale.Comment: Accepted for publication in Ap

RR Lyrae stars as standard candles in the Gaia Data Release 2 Era

We present results from the analysis of 401 RR Lyrae stars (RRLs) belonging to the field of the Milky Way (MW). For a fraction of them multi-band ($V$, $K_{\rm s}$, $W1$) photometry, metal abundances, extinction values and pulsation periods are available in the literature and accurate trigonometric parallaxes measured by the Gaia mission alongside Gaia $G$-band time-series photometry have become available with the Gaia second data release (DR2) on 2018 April 25. Using a Bayesian fitting approach we derive new near-, mid-infrared period-absolute magnitude-metallicity ($PMZ$) relations and new absolute magnitude-metallicity relations in the visual ($M_V - {\rm [Fe/H]}$) and $G$ bands ($M_G - {\rm [Fe/H]}$), based on the Gaia DR2 parallaxes. We find the dependence of luminosity on metallicity to be higher than usually found in the literature, irrespective of the passband considered. Running the adopted Bayesian model on a simulated dataset we show that the high metallicity dependence is not caused by the method, but likely arises from the actual distribution of the data and the presence of a zero-point offset in the Gaia parallaxes. We infer a zero-point offset of $-0.057$ mas, with the Gaia DR2 parallaxes being systematically smaller. We find the RR Lyrae absolute magnitude in the $V$, $G$, $K_{\rm s}$ and $W1$ bands at metallicity of [Fe/H]=$-1.5$ dex and period of P = 0.5238 days, based on Gaia DR2 parallaxes to be $M_V = 0.66\pm0.06$ mag, $M_G = 0.63\pm0.08$ mag, $M_{K_{\rm s}} = -0.37\pm0.11$ mag and $M_{W1} = -0.41\pm0.11$ mag, respectively.Comment: 18 pages, 21 figures, 4 tables. Accepted for publication in MNRA

Dwarf spheroidal satellites of M31: I. Variable stars and stellar populations in Andromeda XIX

We present B,V time-series photometry of Andromeda XIX (And XIX), the most extended (half-light radius of 6.2') of Andromeda's dwarf spheroidal companions, that we observed with the Large Binocular Cameras at the Large Binocular Telescope. We surveyed a 23'x 23' area centered on And XIX and present the deepest color magnitude diagram (CMD) ever obtained for this galaxy, reaching, at V~26.3 mag, about one magnitude below the horizontal branch (HB). The CMD shows a prominent and slightly widened red giant branch, along with a predominantly red HB, which, however, extends to the blue to significantly populate the classical instability strip. We have identified 39 pulsating variable stars, of which 31 are of RR Lyrae type and 8 are Anomalous Cepheids (ACs). Twelve of the RR Lyrae variables and 3 of the ACs are located within And XIX's half light radius. The average period of the fundamental mode RR Lyrae stars ( = 0.62 d, \sigma= 0.03 d) and the period-amplitude diagram qualify And XIX as an Oosterhoff-Intermediate system. From the average luminosity of the RR Lyrae stars ( = 25.34 mag, \sigma= 0.10 mag) we determine a distance modulus of (m-M)$_0$=$24.52\pm0.23$ mag in a scale where the distance to the Large Magellanic Cloud (LMC) is $18.5\pm0.1$ mag. The ACs follow a well defined Period-Wesenheit (PW) relation that appears to be in very good agreement with the PW relationship defined by the ACs in the LMC.Comment: accepted for publication in Ap

Gaia's Cepheids and RR Lyrae Stars and Luminosity Calibrations Based on Tycho-Gaia Astrometric Solution

Gaia Data Release 1 contains parallaxes for more than 700 Galactic Cepheids and RR Lyrae stars, computed as part of the Tycho-Gaia Astrometric Solution (TGAS). We have used TGAS parallaxes, along with literature ($V, I, J, {K_\mathrm{s}}, W_1$) photometry and spectroscopy, to calibrate the zero point of the Period-Luminosity and Period-Wesenheit relations of classical and type II Cepheids, and the near-infrared Period-Luminosity, Period-Luminosity-Metallicity and optical Luminosity-Metallicity relations of RR Lyrae stars. In this contribution we briefly summarise results obtained by fitting these basic relations adopting different techniques that operate either in parallax or distance (absolute magnitude) space.Comment: 5 pages, 4 figures, proceedings for the 22nd Los Alamos Stellar Pulsation Conference Series Meeting "Wide field variability surveys: a 21st-century perspective", held in San Pedro de Atacama, Chile, Nov. 28 - Dec. 2, 201

The complex surgical management of the first case of severe combined immunodeficiency and multiple intestinal atresias surviving after the fourth year of life

Severe combined immunodeficiency (SCID) is a life-threatening syndrome of recurrent infections and gastrointestinal alterations due to severe compromise of T cells and B cells. Clinically, most patients present symptoms before the age of 3 months and without intervention SCID usually results in severe infections and death by the age of 2 years. Its association with intestinal anomalies as multiple intestinal atresias (MIA) is rare and worsens the prognosis, resulting lethal. We describe the case of a four year-old boy with SCID-MIA. He presented at birth with meconium peritonitis, multiple ileal atresias and underwent several intestinal resections. A targeted Sanger sequencing revealed a homozygous 4-bp deletion (c.313ΔTATC; p.Y105fs) in tetratricopeptide repeat domain 7A (TTC7A). He experienced surgical procedures including resection and stricturoplasty. Despite parenteral nutrition-associated liver disease, the patient is surviving at the time of writing the report. Precocious immune system assessment, scrutiny of TTC7A mutations and prompt surgical procedures are crucial in the management