137 research outputs found
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
SPRITZ is sparkling: Simulated CO and [C II] luminosities
Aims. We present a new prediction for the luminosity functions (LFs) of the [C II] line at 158 mu M, of the CO lines from J = 0 to J = 24, and of the molecular gas mass density up to z = 10, using the Spectro-Photometric Realisations of Infrared-selected Targets at all-z (SPRITz) simulation.Methods. We update the state-of-the-art phenomenological simulation SPRITZ to include both the CO (J <= 24) and the [C II] line luminosities. This has been performed using different empirical and theoretical relations to convert the total infrared luminosity (or star formation rate, SFR) to the [C II] or CO luminosity. The resulting line LFs were compared for validation with a large set of observations available in the literature. We then used the derived CO and [C II] line luminosities to estimate the molecular gas mass density and compare it with available observations.Results. The CO and [C II] LFs presented here are in good agreement with all the available observations. In particular, the best results for [C II] are obtained deriving the [C II] luminosity directly from the SFR, but considering a dependence of this relation on the gas metallicity. For all the CO LFs, the estimates favoured by the data are derived considering different relations, depending on the ionisation mechanism dominating each galaxy, namely star formation or active galactic nuclei, and, moreover, by deriving the J >= 4 CO lines directly from the [C II] luminosity. However, further data are necessary to fully distinguish between models. Finally, the best agreements with observations of the molecular gas mass density are derived by converting the [C II] luminosity to H-2 mass, using a [C II]-to-H-2 conversion similar to 130 M-circle dot/L-circle dot. All the line LFs, useful for planning and interpreting future observations, are made publicly available
Untargeted Metabolomics Investigation on Selenite Reduction to Elemental Selenium by Bacillus mycoides SeITE01
Bacillus mycoides SeITE01 is an environmental isolate that transforms the oxyanion selenite ((Formula presented.)) into the less bioavailable elemental selenium (Se0) forming biogenic selenium nanoparticles (Bio-SeNPs). In the present study, the reduction of sodium selenite (Na2SeO3) by SeITE01 strain and the effect of (Formula presented.) exposure on the bacterial cells was examined through untargeted metabolomics. A time-course approach was used to monitor both cell pellet and cell free spent medium (referred as intracellular and extracellular, respectively) metabolites in SeITE01 cells treated or not with (Formula presented.). The results show substantial biochemical changes in SeITE01 cells when exposed to (Formula presented.). The initial uptake of (Formula presented.) by SeITE01 cells (3h after inoculation) shows both an increase in intracellular levels of 4-hydroxybenzoate and indole-3-acetic acid, and an extracellular accumulation of guanosine, which are metabolites involved in general stress response adapting strategies. Proactive and defensive mechanisms against (Formula presented.) are observed between the end of lag (12h) and beginning of exponential (18h) phases. Glutathione and N-acetyl-L-cysteine are thiol compounds that would be mainly involved in Painter-type reaction for the reduction and detoxification of (Formula presented.) to Se0. In these growth stages, thiol metabolites perform a dual role, both acting against the toxic and harmful presence of the oxyanion and as substrate or reducing sources to scavenge ROS production. Moreover, detection of the amino acids L-threonine and ornithine suggests changes in membrane lipids. Starting from stationary phase (24 and 48h), metabolites related to the formation and release of SeNPs in the extracellular environment begin to be observed. 5-hydroxyindole acetate, D-[+]-glucosamine, 4-methyl-2-oxo pentanoic acid, and ethanolamine phosphate may represent signaling strategies following SeNPs release from the cytoplasmic compartment, with consequent damage to SeITE01 cell membranes. This is also accompanied by intracellular accumulation of trans-4-hydroxyproline and L-proline, which likely represent osmoprotectant activity. The identification of these metabolites suggests the activation of signaling strategies that would protect the bacterial cells from (Formula presented.) toxicity while it is converting into SeNPs
ALMA view of a massive spheroid progenitor: a compact rotating core of molecular gas in an AGN host at z=2.226
We present ALMA observations at 107.291 GHz (band 3) and 214.532 GHz (band 6)
of GMASS 0953, a star-forming galaxy at z=2.226 hosting an obscured AGN that
has been proposed as a progenitor of compact quiescent galaxies (QG). We
measure for the first time the size of the dust and molecular gas emission of
GMASS 0953 that we find to be extremely compact (1 kpc). This result,
coupled with a very high ISM density (n10 cm), a low gas
mass fraction (0.2) and a short gas depletion timescale (150 Myr)
imply that GMASS 0953 is experiencing an episode of intense star-formation in
its central region that will rapidly exhaust its gas reservoirs, likely aided
by AGN-induced feedback, confirming its fate as a compact QG. Kinematic
analysis of the CO(6-5) line shows evidence of rapidly-rotating gas
(=320 km s), as observed also in a handful of
similar sources at the same redshift. On-going quenching mechanisms could
either destroy the rotation or leave it intact leading the galaxy to evolve
into a rotating QG.Comment: MNRAS in press, 8 pages, 8 figure
ALMA view of a massive spheroid progenitor: a compact rotating core of molecular gas in an AGN host at z=2.226
We present ALMA observations at 107.291 GHz (band 3) and 214.532 GHz
(band 6) of GMASS 0953, a star-forming galaxy at z = 2.226 hosting an
obscured active galactic nucleus (AGN) that has been proposed as a
progenitor of compact quiescent galaxies (QGs). We measure for the first
time the size of the dust and molecular gas emission of GMASS 0953 that
we find to be extremely compact (similar to 1 kpc). This result, coupled
with a very high interstellar medium (ISM) density (n similar to 10(5.5)
cm(-3)), a low gas mass fraction (similar to 0.2), and a short gas
depletion time-scale (similar to 150 Myr), implies that GMASS 0953 is
experiencing an episode of intense star formation in its central region
that will rapidly exhaust its gas reservoirs, likely aided by
AGN-induced feedback, confirming its fate as a compact QG. Kinematic
analysis of the CO(6-5) line shows evidence of rapidly rotating gas
(V-rot = 320(-53)(+92) km s(-1)), as observed also in a handful of
similar sources at the same redshift. On-going quenching mechanisms
could either destroy the rotation or leave it intact leading the galaxy
to evolve into a rotating QG
Optical and mid-infrared line emission in nearby Seyfert galaxies
Line ratio diagnostics provide valuable clues on the source of ionizing
radiation in galaxies with intense black hole accretion and starbursting
events, such as local Seyfert or galaxies at the peak of the star formation
history. We aim to provide a reference joint optical and mid-IR analysis for
studying AGN identification via line ratios and testing predictions from
photoionization models. We obtained homogenous optical spectra with the
Southern Africa Large Telescope for 42 Seyfert galaxies with Spitzer/IRS
spectroscopy and X-ray to mid-IR multiband data available. After confirming the
power of the main optical ([OIII]) and mid-IR ([NeV], [OIV], [NeIII]) emission
lines in tracing AGN activity, we explore diagrams based on ratios of optical
and mid-IR lines by exploiting photoionization models of different ionizing
sources (AGN, star formation and shocks). We find that pure AGN photoionization
models are good at reproducing observations of Seyfert galaxies with an AGN
fractional contribution to the mid-IR (5-40 micron) emission larger than 50 per
cent. For targets with a lower AGN contribution these same models do not fully
reproduce the observed mid-IR line ratios. Mid-IR ratios like [NeV]/[NeII],
[OIV]/[NeII] and [NeIII]/[NeII] show a dependence on the AGN fractional
contribution to the mid-IR unlike optical line ratios. An additional source of
ionization, either from star formation or radiative shocks, can help explain
the observations in the mid-IR. Among combinations of optical and mid-IR
diagnostics in line ratio diagrams, only those involving the [OI]/Halpha ratio
are promising diagnostics for simultaneously unraveling the relative role of
AGN, star formation and, shocks. A proper identification of the dominant
ionizing source would require the exploitation of analysis tools based on
advanced statistical techniques as well as spatially resolved data.Comment: 31 pages, 15 figures, 2 tables. Accepted for publication in A&
HYPerluminous quasars at the Epoch of ReionizatION (HYPERION). A new regime for the X-ray nuclear properties of the first quasars
The existence of luminous quasars (QSO) at the Epoch of Reionization (EoR;
i.e. z>6) powered by supermassive black holes (SMBH) with masses
challenges models of early SMBH formation. To shed light
on the nature of these sources we started a multiwavelength programme based on
a sample of 18 HYPerluminous quasars at the Epoch of ReionizatION (HYPERION).
These are the luminous QSOs whose SMBH must have had the fastest mass growth
during the Universe first Gyr. In this paper we present the HYPERION sample and
report on the first of the 3 years planned observations of the 2.4 Ms
XMM-Newton Multi-Year Heritage program on which HYPERION is based. The goal of
this program is to accurately characterize the X-ray nuclear properties of QSOs
at the EoR. Through a joint X-ray spectral analysis of 10 sources, in the
rest-frame keV range, we report a steep average photon index
(). Absorption is not required. The average is
inconsistent at level with the canonical 1.8-2 value measured in
QSO at z<6. This spectral slope is also much steeper than that reported in
lower-z QSOs with similar luminosity or accretion rate, thus suggesting a
genuine redshift evolution. Alternatively, we can interpret this result as the
presence of an unusually low-energy cutoff keV on a standard
power-law. We also report on mild indications that HYPERION QSOs
show higher soft X-ray emission at 2 keV compared to the UV one at 2500A than
expected by lower-z luminous AGN. We speculate that a redshift-dependent
coupling between the corona and accretion disc or intrinsically different
coronal properties may account for the steep spectral slopes, especially in the
presence of powerful winds. The reported slopes, if confirmed at lower
luminosities, may have an important impact on future X-ray AGN studies in the
early Universe.Comment: 21 pages (including appendix), 12 figures, 4 tables. Accepted for
pubblication in A&
Probing the high-redshift universe with SPICA: Toward the epoch of reionisation and beyond
With the recent discovery of a dozen dusty star-forming galaxies and around 30 quasars at z > 5 that are hyper-luminous in the infrared (ÎŒ LIR > 1013 Lâ, where ÎŒ is a lensing magnification factor), the possibility has opened up for SPICA, the proposed ESA M5 mid-/far-infrared mission, to extend its spectroscopic studies toward the epoch of reionisation and beyond. In this paper, we examine the feasibility and scientific potential of such observations with SPICAâs far-infrared spectrometer SAFARI, which will probe a spectral range (35â230 ÎŒm) that will be unexplored by ALMA and JWST. Our simulations show that SAFARI is capable of delivering good-quality spectra for hyper-luminous infrared galaxies at z = 5 â 10, allowing us to sample spectral features in the rest-frame mid-infrared and to investigate a host of key scientific issues, such as the relative importance of star formation versus AGN, the hardness of the radiation field, the level of chemical enrichment, and the properties of the molecular gas. From a broader perspective, SAFARI offers the potential to open up a new frontier in the study of the early Universe, providing access to uniquely powerful spectral features for probing first-generation objects, such as the key cooling lines of low-metallicity or metal-free forming galaxies (fine-structure and H2 lines) and emission features of solid compounds freshly synthesised by Population III supernovae. Ultimately, SAFARIâs ability to explore the high-redshift Universe will be determined by the availability of sufficiently bright targets (whether intrinsically luminous or gravitationally lensed). With its launch expected around 2030, SPICA is ideally positioned to take full advantage of upcoming wide-field surveys such as LSST, SKA, Euclid, and WFIRST, which are likely to provide extraordinary targets for SAFARI
Evaluation of COVID-19 impact on DELAYing diagnostic-therapeutic pathways of lung cancer patients in Italy (COVID-DELAY study): fewer cases and higher stages from a real-world scenario
Introduction: COVID-19 has disrupted the global health care system since March 2020. Lung cancer (LC) patients (pts) represent a vulnerable population highly affected by the pandemic. This multicenter Italian study aimed to evaluate whether the COVID-19 outbreak had an impact on access to cancer diagnosis and treatment of LC pts compared with pre-pandemic time. Methods: Consecutive newly diagnosed LC pts referred to 25 Italian Oncology Departments between March and December 2020 were included. Access rate and temporal intervals between date of symptoms onset and diagnostic and therapeutic services were compared with the same period in 2019. Differences between the 2 years were analyzed using the chi-square test for categorical variables and the Mann\u2013Whitney U test for continuous variables. Results: A slight reduction ( 126.9%) in newly diagnosed LC cases was observed in 2020 compared with 2019 (1523 versus 1637, P = 0.09). Newly diagnosed LC pts in 2020 were more likely to be diagnosed with stage IV disease (P < 0.01) and to be current smokers (someone who has smoked more than 100 cigarettes, including hand-rolled cigarettes, cigars, cigarillos, in their lifetime and has smoked in the last 28 days) (P < 0.01). The drop in terms of new diagnoses was greater in the lockdown period (percentage drop 1212% versus 123.2%) compared with the other months included. More LC pts were referred to a low/medium volume hospital in 2020 compared with 2019 (P = 0.01). No differences emerged in terms of interval between symptoms onset and radiological diagnosis (P = 0.94), symptoms onset and cytohistological diagnosis (P = 0.92), symptoms onset and treatment start (P = 0.40), and treatment start and first radiological revaluation (P = 0.36). Conclusions: Our study pointed out a reduction of new diagnoses with a shift towards higher stage at diagnosis for LC pts in 2020. Despite this, the measures adopted by Italian Oncology Departments ensured the maintenance of the diagnostic-therapeutic pathways of LC pts
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