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Plagues and the transmission of diseases constituted one of the major concerns of people during the early modern period. Although there was a consistent effort from the sixteenth century onwards to find proper solutions to relieve the European citizens, the lack of medical knowledge forced these states to focus mostly on the containment of these diseases and not on finding a cure. Thus, the European states used any available resource in this battle against plagues. One of the most prominent allies in this effort to control the outbreak of diseases was the press. Brochures and pamphlets issued by the authorities, reporting the established policies on plagues, circulated in large numbers during the sixteenth century. The emergence of the newspaper in the early seventeenth century increased this circulation. The purpose of this article is to present the role of Francophone newspapers in propagating public health measures through the relevant reports and advertisements on their issues, during a period when the need for medicines increased, the services provided by apothecaries became necessary for the function of the health system and doctors’ involvement was of upmost importance.

A complete census of Active Galactic Nuclei (AGN) is a prerequisite for understanding the growth of supermassive black holes across cosmic time. A significant challenge toward this goal is the whereabouts of heavily obscured AGN that remain uncertain. This paper sets new constraints on the demographics of this population by developing a methodology that combines X-ray spectral information with priors derived from multiwavelength observations. We select X-ray AGN in the Chandra COSMOS Legacy survey and fit their $2.2-500\mu m$ spectral energy distributions with galaxy and AGN templates to determine the mid-infrared ($6\mu m$) luminosity of the AGN component. Empirical correlations between X-ray and $6\mu m$ luminosities are then adopted to infer the intrinsic accretion luminosity at X-rays for individual AGN. This is used as prior information in our Bayesian X-ray spectral analysis to estimate physical properties, such as line-of-sight obscuration. Our approach breaks the degeneracies between accretion luminosity and obscuration that affect X-ray spectral analysis, particularly for the most heavily obscured (Compton-Thick) AGN with low photon counts X-ray spectra. The X-ray spectral results are then combined with the selection function of the Chandra COSMOS Legacy survey to derive the AGN space density and a Compton-Thick fraction of $21.0^{+16.1}_{-9.9}\%$ at redshifts $z, Comment: Accepted for publication at MNRAS, 21 pages, 20 figures, 6 tables

This paper explores the role of small-scale environment ($, Accepted in Monthly Notices of the Royal Astronomical Society

An empirical model is presented that links the demographics of AGN to their ensemble X-ray variability properties. Observations on the incidence of AGN in galaxies are combined with (i) models of the Power Spectrum Density (PSD) of the flux variations of AGN and (ii) parameterisations of the black-hole mass vs stellar-mass scaling relation, to predict the mean excess variance of active black-hole populations in cosmological volumes. We show that the comparison of the model with observational measurements of the ensemble excess variance as a function of X-ray luminosity provides a handle on both the PSD models and the black-hole mass vs stellar mass relation. We find strong evidence against a PSD model that is described by a broken power-law and a constant overall normalisation. Instead our analysis indicates that the amplitude of the PSD depends on the physical properties of the accretion events, such as the Eddington ratio and/or the black hole mass. We also find that current observational measurements of the ensemble excess variance are consistent with the black-hole mass vs stellar mass relation of local spheroids based on dynamically determined black-hole masses. We also discuss future prospects of the proposed approach to jointly constrain the PSD of AGN and the black-hole mass vs stellar mass relation as a function of redshift. The mock AGN catalogue used in the paper is made available. The contents are described in the README file. The code used in the paper is available at https://github.com/ageorgakakis/EnsembleVariability. Full details can be found in the associated paper at https://arxiv.org/abs/2105.08752., The code that uses this data is available at https://github.com/ageorgakakis/EnsembleVariability The paper describing the modeling approach is available at https://arxiv.org/abs/2105.08752, {"references":["https://arxiv.org/abs/2105.08752"]}

Past efforts to relate board diversity and shareholder activism have mainly focused on directors’ gender in isolation, stressing that female board representation associates with lower shareholder activism. By considering gender as the only diversity dimension, however, this approach neglects the complex and multidimensional nature of the diversity construct. In this chapter, we draw on the notion of ‘intersectionality’ to argue that dual minority status in corporate boards (e.g., representation of directors with both gender and ethnic minority status) instead triggers a higher number of governance-related shareholder resolutions, a prominent form of shareholder activism. Our theory suggests that firms need to simultaneously consider the multiple configurations of board diversity. It also sheds light on the career disadvantages that dual minority directors may face due to shareholder resolutions - stressing that duality of minority status may associate with greater barriers at the board-shareholder interface.

XMM-Newton, a European Space Agency observatory, has been observing the X-ray, ultra-violet and optical sky for 23 years. During this time, astronomy has evolved from mainly studying single sources to populations and from a single wavelength, to multi-wavelength or messenger data. We are also moving into an era of time domain astronomy. New software and methods are required to accompany evolving astronomy and prepare for the next generation X-ray observatory, Athena. Here we present XMM2ATHENA, a programme funded by the European Union's Horizon 2020 research and innovation programme. XMM2ATHENA builds on foundations laid by the XMM-Newton Survey Science Centre (XMM-SSC), including key members of this consortium and the Athena Science ground segment, along with members of the X-ray community. The project is developing and testing new methods and software to allow the community to follow the X-ray transient sky in quasi-real time, identify multi-wavelength or messenger counterparts of XMM-Newton sources and determine their nature using machine learning. We detail here the first milestone delivery of the project, a new online, sensitivity estimator. We also outline other products, including the forthcoming innovative stacking procedure and detection algorithms to detect the faintest sources. These tools will then be adapted for Athena and the newly detected or identified sources will enhance preparation for observing the Athena X-ray sky., Comment: 7 pages, 1 figure, accepted for publication in Astronomische Nachrichten

This paper presents the construction of the RapidXMM database that is available through the XMM-Newton Science Archive and offers access to upper limits and aperture photometry across the field of view of the XMM-Newton Pointed and Slew Survey observations. The feature of RapidXMM is speed. It enables the fast retrieval of X-ray upper limits and photometry products in three energy bands (0.2-2, 2-12, 0.2-12 keV) for large numbers of input sky positions. This is accomplished using the Hierarchical Equal Area Iso Latitude pixelation of the sphere (HEALPix). The pre-calculated upper-limits and associated X-ray photometry products are reprojected into the HEALPix grid of cells before being ingested into the RapidXMM database. This results in tables of upper limits and aperture photometry within HEALPix cells of size ~3 arcsec (Pointed Observations) and ~6 arcsec (Slew Survey). The database tables are indexed by the unique integer number of the HEALPix cells. This reduces spatial nearest-neighbor queries by sky position to an integer-matching exercise and significantly accelerates the retrieval of results. We describe in detail the processing steps that lead from the science products available in the XMM-Newton archive to a database optimised for sky queries. We also present two simple show-case applications of RapidXMM for scientific studies: searching for variable X-ray sources, and stacking analysis of X-ray faint populations, Comment: 20 pages, 20 figures. This article has been accepted for publication in MNRAS. Published by Oxford University Press on behalf of the Royal Astronomical Society

To understand the Active Galactic Nuclei (AGN) phenomenon and their impact on the evolution of galaxies, a complete AGN census is required; however, finding heavily obscured AGNs is observationally challenging. Here we use the deep and extensive multi-wavelength data in the COSMOS field to select a complete sample of 578 infrared (IR) quasars ($L_{\rm AGN,IR}>10^{45}\rm \: erg\: s^{-1}$) at $z10^{22}\rm \: cm^{-2}$) and identify differences in the average properties between the obscured and unobscured quasars: (1) obscured quasars have star-formation rates $\approx 3$ times higher than unobscured systems for no significant difference in stellar mass and (2) obscured quasars have stronger radio emission than unobscured systems, with a radio-loudness parameter $\approx 0.2 \rm \: dex$ higher. These results are inconsistent with a simple orientation model but in general agreement with either extreme host-galaxy obscuration towards the obscured quasars or a scenario where obscured quasars are an early phase in the evolution of quasars.

This work explores the role of small-scale environment (< 1 Mpc) in modulating accretion events onto supermassive black holes by studying the incidence of Active Galactic Nuclei (AGN) in massive clusters of galaxies. A flexible, data-driven semi-empirical model is developed based on a minimal set of parameters and under the zero order assumption that the incidence of AGN in galaxies is independent of environment. This is used to predict how the fraction of X-ray selected AGN among galaxies in massive dark matter halos (\(\gtrsim 3 \times 10^{14}\,\rm{M}_{\odot}\) ) evolves with redshift and reveal tensions with observations. At high redshift, \(z\sim1.2\), the model underpredicts AGN fractions, particularly at high X-ray luminosities, \(L_X(\rm 2-10\,keV) \gtrsim 10^{44}\, erg \, s^{-1}\). At low redshift, \(z\sim0.2\), the model estimates fractions of moderate luminosity AGN (\(L_X(\rm 2-10\,keV) \gtrsim 10^{43}\, erg \, s^{-1}\)) that are a factor of 2-3 higher than the observations. These findings reject the zero order assumption on which the semi-empirical model hinges and point to a strong and redshift-dependent influence of the small-scale environment on the growth of black holes. Cluster of galaxies appear to promote AGN activity relative to the model expectation at\(z\sim1.2\) and suppress it close to the present day. These trends could be explained by the increasing gas content of galaxies toward higher redshift combined with an efficient triggering of AGN at earlier times in galaxies that fall onto clusters.

Which galaxies in the general population turn into active galactic nuclei (AGNs) is a keystone of galaxy formation and evolution. Thanks to SRG/eROSITA's contiguous 140 square degree pilot survey field, we constructed a large, complete, and unbiased soft X-ray flux-limited ($F_X>6.5\times 10^{-15}$ erg s$^{-1}$ cm$^{-2}$) AGN sample at low redshift, $0.05, Comment: 17 pages, 9 figures, 2 tables. A&A: Received: 19 December 2022 / Accepted: 21 March 2023

Studies indicate strong evidence of a scaling relation in the local Universe between the supermassive black hole mass ($M_\rm{BH}$) and the stellar mass of their host galaxies ($M_\star$). They even show similar histories across cosmic times of their differential terms: star formation rate (SFR) and black hole accretion rate (BHAR). However, a clear picture of this coevolution is far from being understood. We select an X-ray sample of active galactic nuclei (AGN) up to $z=2.5$ in the miniJPAS footprint. Their X-ray to infrared spectral energy distributions (SEDs) have been modeled with CIGALE, constraining the emission to 68 bands. For a final sample of 308 galaxies, we derive their physical properties (e.g., $M_\star$, $\rm{SFR}$, $\rm{SFH}$, and $L_\rm{AGN}$). We also fit their optical spectra for a subsample of 113 sources to estimate the $M_\rm{BH}$. We calculate the BHAR depending on two radiative efficiency regimes. We find that the Eddington ratios ($\lambda$) and its popular proxy ($L_\rm{X}$/$M_\star$) have 0.6 dex of difference, and a KS-test indicates that they come from different distributions. Our sources exhibit a considerable scatter on the $M_\rm{BH}$-$M_\star$ relation, which can explain the difference between $\lambda$ and its proxy. We also model three evolution scenarios to recover the integral properties at $z=0$. Using the SFR and BHAR, we show a notable diminution in the scattering between $M_\rm{BH}$-$M_\star$. For the last scenario, we consider the SFH and a simple energy budget for the AGN accretion, obtaining a relation similar to the local Universe. Our study covers $\sim 1$ deg$^2$ in the sky and is sensitive to biases in luminosity. Nevertheless, we show that, for bright sources, the link between SFR and BHAR, and their decoupling based on an energy limit is the key that leads to the local $M_\rm{BH}$-$M_\star$ scaling relation., Comment: Accepted for publication in A&A

The article presents the emergence of the three major French-language gazettes published in the Dutch Republic during the seventeenth and eighteenth century, the Gazette d’Amsterdam, Gazette de Leyde, and the Gazette de Rotterdam. All of them had Huguenot publishers, especially after the Revocation of the Edict of Nantes. The gazettes became famous during the two major wars of the King Louis XIV, the War of the Great Alliance, and the War of the Spanish Succession. They were circulated in large numbers not only among the Huguenot diaspora but also in France. At that time, France had only one gazette, the constitutional Gazette de Paris. The three Huguenot gazettes presented updated reports from every major city or military camp. Their reports and their attitude towards France, however, varied. This article enlightens the attitude of each Huguenot gazette towards France, presenting reports of the last two years of the War of the Great Alliance.

15 pages, 6 figures.-- This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), Increasing anthropogenic pressures on the coastal marine environments impact these ecosystems via a variety of mechanisms including nutrient loading, leading to eutrophication and increases in algal blooms. Here, we use a metagenomics approach to assess the taxonomic and functional changes of the microbial community throughout a nutrient enriched mesocosm phytoplankton bloom. We tested four different nutrient treatments consisting of either nitrate and phosphate or nitrate, phosphate and silicate, administered on the first day or continuously for the first two weeks of the experiment. Our results show a shift in the taxonomic composition of the community over time that is dependent on the nutrient addition regime. Significant differences in the functional potential of the communities were detected, with an interaction between bloom period (pre-bloom, bloom and post-bloom) and nutrient treatment (p = 0.004). A sharp drop in functional similarity was observed in the first week in all treatments and after 20 days had not returned to pre-bloom levels. Changes within energy metabolism pathways showed a remarkable enrichment of the dissimilatory nitrate reduction pathway in the post-bloom period. Eukaryotic oxidative phosphorylation and photosynthetic antenna proteins were more abundant during the bloom, especially in the continuous treatment with silicate. Our results suggest that continuous (i.e. chronic) nutrient enrichment has a larger effect on the functioning of marine systems compared to a single (i.e acute) addition. A deep understanding of the functional and taxonomic shifts in the community during blooms is essential to reverse or mitigate human impacts on coastal environments, This research was supported by baseline funding provided by KAUST to Prof. Xabier Irigoien

Cet article formule l’hypothese que l’objectivation comptable de la fonction publique europeenne (FPE) est le reflet de luttes qui ont pour enjeu la definition de l’Europe politique. Ce faisant, il vise a eclairer la facon dont cet enjeu pese, en amont, sur la definition de cette fonction publique et les problematisations changeantes dont elle fait l’objet dans le temps et dans l’espace du pouvoir europeen. Apres avoir rappele quelques elements clefs de l’histoire de la politique de la FPE, l’article donne a voir deux processus successifs : celui de l’objectivation sociale de cette fonction publique, sous l’effet de la monopolisation de la construction europeenne par l’administration de l’Union europeenne jusque dans les annees 1990 ; celui de sa mise sous pression (voire de son « objectification ») sous l’effet de forces heteronomes et de la redefinition de ses fonctions a l’aune du nouveau management public international et des enjeux budgetaires.

To understand the Active Galactic Nuclei (AGN) phenomenon and their impact on the evolution of galaxies, a complete AGN census is required; however, finding heavily obscured AGNs is observationally challenging. Here we use the deep and extensive multi-wavelength data in the COSMOS field to select a complete sample of 578 infrared (IR) quasars ($L_{\rm AGN,IR}>10^{45}\rm \: erg\: s^{-1}$) at $z10^{22}\rm \: cm^{-2}$) and identify differences in the average properties between the obscured and unobscured quasars: (1) obscured quasars have star-formation rates $\approx 3$ times higher than unobscured systems for no significant difference in stellar mass and (2) obscured quasars have stronger radio emission than unobscured systems, with a radio-loudness parameter $\approx 0.2 \rm \: dex$ higher. These results are inconsistent with a simple orientation model but in general agreement with either extreme host-galaxy obscuration towards the obscured quasars or a scenario where obscured quasars are an early phase in the evolution of quasars., Accepted for publication in MNRAS. 22 pages, 15 figures, 4 tables

We aim at characterizing the hot phase of the Circum-Galactic Medium in a large sample of galaxies. We stack X-ray events from the SRG/eROSITA eFEDS survey around central galaxies in the GAMA 9hr field to construct radially projected soft X-ray luminosity profiles as a function of their stellar mass and specific star formation rate. We consider samples of quiescent (star-forming) galaxies in the stellar mass range $2\times 10^{10}$ -- $10^{12}$ M$_\odot$ ($3\times 10^9$ -- $6\times10^{11}$ M$_\odot$). For quiescent galaxies, the X-ray profiles are clearly extended throughout the available mass range; however, the measured profile is likely biased high due to projection effects, as these galaxies tend to live in dense and hot environments. For the most massive star forming samples ($\geq10^{11}$ M$_\odot$), there is a hint of detection of extended emission. For star-forming galaxies with $< 10^{11}$ M$_\odot$ the X-ray stacked profiles are compatible with unresolved sources and consistent with the expected emission from faint Active Galactic Nuclei and X-ray binaries. We measure for the first time the mean relation between average X-ray luminosity and stellar mass separately for quiescent and star-forming galaxies. High-mass ($\geq 10^{11}$ M$_\odot$) star-forming or quiescent galaxies follow the expected scaling of virialized hot haloes, while lower mass star-forming galaxies show a less prominent luminosity and a weaker dependence on stellar mass, consistent with empirical models of the weak AGN population. When comparing our results with state-of-the art numerical simulations, we find an overall consistency on large ($>80$ kpc) scales at masses $\geq 10^{11}$ M$_\odot$, but disagreement on the small scales, where brighter than observed compact cores are predicted. Simulations also do not predict the clear differentiation that we observe between quiescent and star-forming galaxies., Comment: 23 pages, 11 figures, 4 tables, accepted in A&A

Studies argue that generalist CEOs are more valued by the market for executive labor and receive higher initial compensation. Challenging this prevailing assumption, we acknowledge the drawbacks of extensive career mobility and predict an inverted U-shape relationship between CEO generalist career experience and CEO initial compensation. Integrating the generalism and specialization views of human capital, we postulate that at an initial level, the acquisition of experience breadth from different firms and industries enables CEOs to broaden their knowledge base, obtain a variety of skills, and thus increase their labor market value and initial compensation. After a threshold, however, the accumulation of extensive levels of career generalism through frequent job hopping across firm and industry contexts gradually causes a lack of experience depth and insufficient career specialization, thereby triggering lower CEO market value and initial pay. Data from 197 CEO appointments in large, publicly traded firms support our predictions. Our results also show that the observed inverted U-shape relationship varies with factors nested at different layers of context, highlighting the contingent nature of this area of research.

Context. High-redshift quasars signpost the early accretion history of the Universe. The penetrating nature of X-rays enables a less absorption-biased census of the population of these luminous and persistent sources compared to optical/near-infrared colour selection. The ongoing SRG/eROSITA X-ray all-sky survey offers a unique opportunity to uncover the bright end of the high-z quasar population and probe new regions of colour parameter space. Aims. We searched for high-z quasars within the X-ray source population detected in the contiguous ~140 deg2 field observed by eROSITA during the performance verification phase. With the purpose of demonstrating the unique survey science capabilities of eROSITA, this field was observed at the depth of the final all-sky survey. The blind X-ray selection of high-redshift sources in a large contiguous, near-uniform survey with a well-understood selection function can be directly translated into constraints on the X-ray luminosity function (XLF), which encodes the luminosity-dependent evolution of accretion through cosmic time. Methods. We collected the available spectroscopic information in the eFEDS field, including the sample of all currently known optically selected z > 5.5 quasars and cross-matched secure Legacy DR8 counterparts of eROSITA-detected X-ray point-like sources with this spectroscopic sample. Results. We report the X-ray detection of eFEDSU J083644.0+005459, an eROSITA source securely matched to the well-known quasar SDSS J083643.85+005453.3 (z = 5.81). The soft X-ray flux of the source derived from eROSITA is consistent with previous Chandra observations. The detection of SDSS J083643.85+005453.3 allows us to place the first constraints on the XLF at z > 5.5 based on a secure spectroscopic redshift. Compared to extrapolations from lower-redshift observations, this favours a relatively flat slope for the XLF at z ~ 6 beyond L*, the knee in the luminosity function. In addition, we report the detection of the quasar with LOFAR at 145 MHz and ASKAP at 888 MHz. The reported flux densities confirm a spectral flattening at lower frequencies in the emission of the radio core, indicating that SDSS J083643.85+005453.3 could be a (sub-) gigahertz peaked spectrum source. The inferred spectral shape and the parsec-scale radio morphology of SDSS J083643.85+005453.3 indicate that it is in an early stage of its evolution into a large-scale radio source or confined in a dense environment. We find no indications for a strong jet contribution to the X-ray emission of the quasar, which is therefore likely to be linked to accretion processes. Conclusions. Our results indicate that the population of X-ray luminous AGNs at high redshift may be larger than previously thought. From our XLF constraints, we make the conservative prediction that eROSITA will detect ~90 X-ray luminous AGNs at redshifts 5.7 < z < 6.4 in the full-sky survey (De+RU). While subject to different jet physics, both high-redshift quasars detected by eROSITA so far are radio-loud; a hint at the great potential of combined X-ray and radio surveys for the search of luminous high-redshift quasars.

Our objective is to critically assess the X-ray flux variability as a tool for measuring the black hole (BH) mass in active galactic nuclei (AGN). We aim to establish a prescription for estimating BH masses based on measurements of the normalised excess variance from X-ray data. We discuss the minimum requirements in terms of the light-curve duration and X-ray signal-to-noise ratio (S/N) to enable a reliable determination that is comparable to what can be derived from the continuum and emission line reverberation studies. We used the light curves of local Seyfert from the Nuclear Spectroscopic Telescope Array hard X-ray mission (NuSTAR), to compute the normalised excess variance (NXV) in the 3-10 and 10-20 keV bands, thus extending the analysis to an energy band higher than 10 keV. The excess variance measurements were then combined with independent BH mass estimates from the literature to establish the MBH versus NXV relation for different samples and weigh its accuracy in terms of the light-curve duration and X-ray S/N. We find that it is possible to accurately measure the BH mass in AGN using excess variance measurements in the 3-10 and the 10-20 keV bands, however, strong quality requirements should be applied. The minimum necessary S/N and duration of the light curves used to compute the excess variance ought to be 3 and approximately 100 ks, respectively. We provide a linear relationship between the normalised excess variance and the black hole mass that can be used to estimate the latter, with an average uncertainty of the order of 0.4 to 0.25 dex (depending on the adopted light-curve segment duration)., 20 pages, 8 figures

Τα σημερινά πληροφοριακά συστήματα χαρακτηρίζονται από αυξημένη πολυπλοκότητα και την ανάγκη να εξυπηρετούν ταυτόχρονα πολλαπλούς χρήστες με διαφορετικές απαιτήσεις. Σε κάθε περίπτωση, κοινή απαίτηση όλων των σύγχρονων πληροφοριακών συστημάτων είναι η προστασία της πληροφορίας κατά τη διακίνησή της μέσα σε αυτά. Προαπαιτούμενο για την επιτυχή προστασία των πόρων ενός συστήματος είναι η αυθεντικοποίηση των χρηστών από αποκτούν πρόσβαση σε αυτό και κατόπιν η εφαρμογή κανόνων διαχείρισης πρόσβασης όπου καθορίζεται τι δικαιώματα κατέχει ο κάθε χρήστης.Η πιο διαδεδομένη μέθοδος αυθεντικοποίησης, παρά τα προβλήματα που παρουσιάζει, είναι η χρήση κωδικών πρόσβασης. Ωστόσο, η ανθρώπινη ικανότητα να απομνημονεύουμε οπτική πληροφορία έχει δώσει το έναυσμα για έντονη ερευνητική δραστηριότητα στην αυθεντικοποίηση με χρήση γραφικών κωδικών ως μια πιο αξιόπιστη εναλλακτική λύση στους κωδικούς κειμένου. Όμως, τα μοντέλα γραφικών κωδικών παρουσιάζουν όχι μόνο προβλήματα αποδοχής χρήσης από τους χρήστες αλλά και ζητήματα ασφάλειας. Κατανοώντας τις αδυναμίες αυτές η παρούσα διατριβή προτείνει ένα καινοτόμο μοντέλο αυθεντικοποίησης το Novel Authentication with Visual Information (NAVI), το οποίο είναι βασισμένο σε οπτική πληροφορία και το οποίο παρέχει υψηλού επιπέδου ασφάλεια. Το προτεινόμενο σύστημα αυθεντικοποίησης χρησιμοποιεί ως διαπιστευτήρια την διαδρομή που επιλέγει ένας χρήστης σε έναν προκαθορισμένο χάρτη. Στη διατριβή αυτή, πραγματοποιείται ανάλυση της ασφάλειας που παρέχει το NAVI σε θεωρητικό επίπεδο και επιπλέον αναπτύχθηκε μια πρότυπη υλοποίηση με την οποία πραγματοποιήθηκαν δοκιμές χρηστών για την αξιολόγηση της ευκολίας χρήσης και της ασφάλειας του παραγόμενου κωδικού. Επιπλέον, ζητήθηκε από τους χρήστες που συμμετείχαν στις δοκιμές να απαντήσουν σε ένα ερωτηματολόγιο αξιολόγησης προκειμένου να ληφθεί υπόψη η γνώμη τους σε μια σειρά από ζητήματα που αφορούν την υλοποίηση του NAVI.Εφόσον έχει πιστοποιηθεί ότι ένας χρήστης είναι αυτός που υποστηρίζει ότι είναι θα πρέπει να του αποδωθούν τα κατάλληλα δικαιώματα πρόσβασης. Η πλειοψηφία των μοντέλων ελέγχου πρόσβασης που έχουν αναπτυχθεί βασίζονται στην υπόθεση ότι τα δικαιώματα πρόσβασης των χρηστών μπορεί να καθοριστούν εκ των προτέρων. Ωστόσο, σε ένα σύγχρονο περιβάλλον συχνά προκύπτουν καταστάσεις έκτακτης ανάγκης που οδηγούν σε αιτήματα πρόσβασης που δεν έχουν προβλεφθεί από τις συνήθεις διαδικασίες. Έχοντας εντοπίσει την ανάγκη αυτή προτείνουμε ένα καινοτόμο μοντέλο διαχείρισης πρόσβασης το Dynamic Spatio Temporal EMergency Role Based Access Control (DSTEM-RBAC), το οποίο βασίζεται στο μοντέλο διαχείρισης πρόσβασης με ρόλους (Role Based Access Control – RBAC). Tο DSTEM-RBAC λαμβάνει υπόψη του χρονικούς και χωρικούς περιορισμούς αλλά το σημαντικότερο είναι ότι προσφέρει έναν ελεγχόμενο και ασφαλή τρόπο για να παρακαμφθούν οι στατικές πολιτικές ασφαλείας χρησιμοποιώντας δυναμικές πληροφορίες για να καταλήξει σε μια απόφαση κατ’ εξαίρεση πρόσβασης η οποία θα παρακάμπτει την στατική πολιτική ασφαλείας που εφαρμόζεται. Στο προτεινόμενο μοντέλο η ιεραρχία των ρόλων αναπαρίσταται ως ένας κατευθυνόμενος γράφος με βάρη, όπου κάθε ρόλος αποτελεί έναν κόμβο. Οι αποστάσεις μεταξύ των κόμβων είναι μια παράμετρος-κλειδί για την προτεινόμενη διαδικασία της κατ’ εξαίρεση πρόσβασης. Επί της ουσίας, η απόσταση μεταξύ ρόλων σε συνδυασμό με τους χρονικούς και τους χωρικούς περιορισμούς και η δυναμική πληροφορία καθορίζουν την κατ’ εξαίρεση πρόσβαση. Οι δυναμικές πληροφορίες που λαμβάνονται υπόψη αποτελούνται από την τοποθεσία του χρήστη, το επίπεδο ασφαλείας και το επίπεδο έκτατης ανάγκης που βρίσκεται ο οργανισμός καθώς και το επίπεδο των κινδύνων από το διαδίκτυο. Η προτεινόμενη αρχιτεκτονική , η οποία είναι επί της ουσίας μια επέκταση του XACML, αναλύεται σε βάθος και παρουσιάζεται μια πρότυπη υλοποίηση με στόχο να αναδειχθεί η εφαρμοσιμότητα του προτεινόμενου μοντέλου στον χώρο της υγείας.Επιπλέον, παρέχεται και μια μεθοδολογία για την αξιολόγηση της συμπεριφοράς των χρηστών έτσι ώστε να είναι εφικτό να βελτιστοποιηθεί η παραμετροποίηση που έχει εφαρμοστεί και να εντοπιστεί μια πιθανή κατάχρηση της λειτουργικότητας της κατ’ εξαίρεση πρόσβασης. Τέλος, πραγματοποιήθηκε μια έρευνα σε δύο κλινικές ως μελέτες περίπτωσης για την αξιολόγηση των αναγκών που υπάρχει για κατ’ εξαίρεση προσβάσεις.

We map the co-eval growth of galaxies and their central supermassive black holes in detail by measuring the incidence of Active Galactic Nuclei (AGN) in galaxies as a function of star formation rate (SFR) and redshift (to z~4). We combine large galaxy samples with deep Chandra X-ray imaging to measure the probability distribution of specific black hole accretion rates (LX relative to stellar mass) and derive robust AGN fractions and average specific accretion rates. First, we consider galaxies along the main sequence of star formation. We find a linear correlation between the average SFR and both the AGN fraction and average specific accretion rate across a wide range in stellar mass ($M_* \sim 10^{8.5-11.5}M_\odot$) and to at least z~2.5, indicating that AGN in main-sequence galaxies are driven by the stochastic accretion of cold gas. We also consider quiescent galaxies and find significantly higher AGN fractions than predicted, given their low SFRs, indicating that AGN in quiescent galaxies are fuelled by additional mechanisms (e.g. stellar winds). Next, we bin galaxies according to their SFRs relative to the main sequence. We find that the AGN fraction is significantly elevated for galaxies that are still star-forming but with SFRs below the main sequence, indicating further triggering mechanisms enhance AGN activity within these sub-main-sequence galaxies. We also find that the incidence of high-accretion-rate AGN is enhanced in starburst galaxies and evolves more mildly with redshift than within the rest of the galaxy population, suggesting mergers play a role in driving AGN activity in such high-SFR galaxies., Comment: 19 pages, 15 figures. This is a pre-copyedited, author-produced version of an article accepted for publication in MNRAS following peer review

Do female CEOs reduce gender-pay disparities in top management teams (TMTs)? Some scholars draw on social identity theory to argue that, as individuals tend to identify with and support their in-groups, appointing a female corporate leader (i.e., CEO) will mitigate the gender-pay gap among executives. Yet, others draw on the queen-bee syndrome to postulate that some female CEOs may rather strengthen gender-pay disparities in upper echelons – by favoring out-groups (male) more than their in-groups (female). We bring together these opposing theoretical arguments to develop a ‘beyond CEO gender’ perspective, arguing that the effects of CEO gender on TMT gender-pay disparities should be considered in conjunction with the corporate leaders' values – as reflected by their political ideology. Our research demonstrates that conservative-female CEOs compensate female (versus male) executives lower compared to all other CEO gender-ideology categories (i.e., female-liberal CEOs, male-liberal CEOs, and male-conservative CEOs). Overall, our work contributes to theory on the CEO-TMT interface by highlighting the role of the CEO as the ‘architect’ of executive remuneration.

The 140 square degree Final Equatorial-Depth Survey (eFEDS) field, observed with the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) aboard the Spectrum-Roentgen-Gamma (SRG) mission, provides a first look at the variable eROSITA sky. We analyze the intrinsic X-ray variability of the eFEDS sources, provide X-ray light curves and tables with variability test results in the 0.2-2.3 keV (soft) and 2.3-5.0 keV (hard) bands. respectively. We perform variability tests using the normalized excess variance and maximum amplitude variability methods as performed for the 2RXS catalogue and add results from the Bayesian excess variance and the Bayesian block methods. In total 65 sources have been identified as being significantly variable in the soft band. In the hard band only one source is found to vary significantly. For the most variable sources fits to stellar flare events reveal extreme flare properties. A few highly variable AGN have also been detected. About half of the variable eFEDS sources have been detected at X-rays with eROSITA for the first time. Comparison with 2RXS and XMM observations provide variability information on timescales of years to decades., Comment: To appear on A&A, Special Issue: The Early Data Release of eROSITA and Mikhail Pavlinsky ART-XC on the SRG Mission; 13 pages, 10 figures, accepted June 21, 2021

Theoretical models of galaxy-AGN co-evolution ascribe an important role for the feedback process to a short, luminous, obscured, and dust-enshrouded phase during which the accretion rate of the SMBH is expected to be at its maximum and the associated AGN-driven winds are also predicted to be maximally developed. To test this scenario, we have isolated a text-book candidate from the eROSITA Final Equatorial-Depth Survey (eFEDS) obtained within the Performance and Verification program of the eROSITA telescope on board Spectrum Roentgen Gamma. From an initial catalog of 246 hard X-ray selected sources matched with the photometric and spectroscopic information available within the eROSITA and Hyper Suprime-Cam consortia, three candidates Quasars in the feedback phase have been isolated applying the diagnostic proposed in Brusa et al. (2015). Only one source (eFEDSU J091157.5+014327) has a spectrum already available (from SDSS-DR16, z=0.603) and it unambiguously shows the presence of a broad component (FWHM~1650 km/s) in the [OIII]5007 line. The associated observed L_[OIII] is ~2.6x10^{42} erg/s, one to two orders of magnitude larger than that observed in local Seyferts and comparable to those observed in a sample of z~0.5 Type 1 Quasars. From the multiwavelength data available we derive an Eddington Ratio (L_bol/L_Edd) of ~0.25, and a bolometric correction in the hard X-ray of k_bol~10, lower than those observed for objects at similar bolometric luminosity. The presence of an outflow, the high X-ray luminosity and moderate X-ray obscuration (L_X~10^44.8 erg/s, N_H~2.7x10^22 cm^-2) and the red optical color, all match the prediction of quasars in the feedback phase from merger driven models. Forecasting to the full eROSITA all-sky survey with its spectroscopic follow-up, we predict that by the end of 2024 we will have a sample of few hundreds such objects at z=0.5-2., Comment: 11 pages, 6 figures, 2 tables. Resubmitted to A&A for the Special Issue: "The Early Data Release of eROSITA and Mikhail Pavlinsky ART-XC on the SRG Mission"

In November 2019, eROSITA on board of SRG observatory started to map the entire sky in X-rays. After the 4-year survey program, it will reach flux limits about 25 times deeper than ROSAT. During the SRG Performance Verification phase, eROSITA observed a contiguous 140 deg$^2$ area of the sky down to the final depth of the eROSITA all-sky survey ("eROSITA Final Equatorial-Depth Survey": eFEDS), with the goal of obtaining a census of the X-ray emitting populations (stars, compact objects, galaxies, clusters of galaxies, AGN) that will be discovered over the entire sky. This paper presents the identification of the counterparts to the point-sources detected in eFEDS in the Main and Hard samples described in Brunner et al 2021, and their multi-wavelength properties, including redshift. For the identification of the counterparts we combined the results from two independent methods (NWAY and ASTROMATCH), trained on the multi-wavelength properties of a sample of 23k XMM-Newton sources detected in the DESI Legacy Imaging Survey DR8. Then spectroscopic redshifts and photometry from ancillary surveys are collated for the computation of photometric redshifts. The eFEDS sources with a reliable counterparts are 24774/27369 (90.5\%) in the Main sample and 231/246 (93.9\%) in the Hard sample, including 2514 (3) sources for which a second counterpart is equally likely. [abridged] This paper is accompanying the eROSITA early data release of all the observations performed during the performance and verification phase. Together with the catalogs of primary and secondary counterparts to the Main and Hard samples of the eFEDS survey this paper releases their multi-wavelength properties and redshifts., Comment: Accepted by A&A for the Special Issue: The Early Data Release of eROSITA and Mikhail Pavlinsky ART-XC on the SRG Mission. NOTE: Paper completely revised wrt the first version submitted to arXiv. Revised catalogs available via https://erosita.mpe.mpg.de/edr/eROSITAObservations/Catalogues/

The eROSITA X-ray telescope on board the Spectrum-Roentgen-Gamma (SRG) satellite has started to detect new X-ray sources over the full sky at an unprecedented rate. Understanding the performance and selection function of the source detection is important for the subsequent scientific analysis of the eROSITA catalogs. Through simulations, we test and optimize the eROSITA source detection procedures, and we characterize the detected catalog quantitatively. Taking the eROSITA Final Equatorial-Depth Survey (eFEDS) as an example, we ran extensive photon-event simulations based on our best knowledge of the instrument characteristics, the background spectrum, and the population of astronomical X-ray sources. We introduce a method of analyzing source detection completeness, purity, and efficiency based on the origin of each photon. According to the source detection efficiency measured in the simulation, we chose a two-pronged strategy to build eROSITA X-ray catalogs, creating a main catalog using only the most sensitive band (0.2-2.3 keV) and an independent hard-band-selected catalog using multiband detection in a range up to 5 keV. Because our mock data are highly representative of the real eFEDS data, we used the mock catalogs to measure the completeness and purity of the eFEDS catalogs as a function of multiple parameters, such as detection likelihood, flux, and luminosity. These measurements provide a basis for choosing the eFEDS catalog selection thresholds. The mock catalogs (available with this paper) can be used to construct the selection function of active galactic nuclei and galaxy clusters. A direct comparison of the output and input mock catalogs also gives rise to a correction curve that converts the raw point-source flux distribution into the intrinsic number counts distribution., Comment: Accepted by A&A for the Special Issue: The Early Data Release of eROSITA and Mikhail Pavlinsky ART-XC on the SRG Mission

The statistical distributions of active galactic nuclei (AGN), i.e. accreting supermassive black holes (BHs), in mass, space and time, are controlled by a series of key properties, namely the BH-galaxy scaling relations, Eddington ratio distributions and fraction of active BHs (duty cycle). Shedding light on these properties yields strong constraints on the AGN triggering mechanisms whilst providing a clear baseline to create useful mock catalogues for the planning of large galaxy surveys. We here delineate a robust methodology to create mock AGN catalogs built on top of large N-body dark matter simulations via state-of-the-art semi-empirical models. We show that by using as independent tests the AGN clustering at fixed X-ray luminosity, galaxy stellar mass and BH mass, along with the fraction of AGN in groups and clusters, it is possible to significantly narrow down the choice in the relation between black hole mass and host galaxy stellar mass, the duty cycle, and the average Eddington ratio distribution, delivering well-suited constraints to guide cosmological models for the co-evolution of BHs and galaxies. Avoiding such a step-by-step methodology inevitably leads to strong degeneracies in the final mock catalogs, severely limiting their usefulness in understanding AGN evolution and in survey planning and testing., Comment: Accepted for publication in the Astrophysical Journal

In the context of the upcoming SRG/eROSITA survey, we present an N-body simulation-based mock catalogue for X-ray-selected active galactic nucleus (AGN) samples. The model reproduces the observed hard X-ray AGN luminosity function (XLF) and the soft X-ray logN-logS from redshift 0 to 6. The XLF is reproduced to within +/- 5 per cent and the logN-logS to within +/- 20 per cent. We develop a joint X-ray - optical extinction and classification model. We adopt a set of empirical spectral energy distributions to predict observed magnitudes in the UV, optical, and NIR. With the latest eROSITA all sky survey sensitivity model, we create a high-fidelity full-sky mock catalogue of X-ray AGN. It predicts their distributions in right ascension, declination, redshift, and fluxes. Using empirical medium resolution optical spectral templates and an exposure time calculator, we find that 1.1 x 10(6) (4 x 10(5)) fibre-hours are needed to follow-up spectroscopically from the ground the detected X-ray AGN with an optical magnitude 21 < r < 22.8 (22.8 < r < 25) with a 4-m (8-m) class multiobject spectroscopic facility. We find that future clustering studies will measure the AGN bias to the per cent level at redshift z < 1.2 and should discriminate possible scenarios of galaxy-AGN co-evolution. We predict the accuracy to which the baryon acoustic oscillation standard ruler will be measured using X-ray AGN: better than 3 per cent for AGN between redshift 0.5 to 3 and better than 1 per cent using the Ly alpha forest of X-ray QSOs discovered between redshift 2 and 3. eROSITA will provide an outstanding set of targets for future galaxy evolution and cosmological studies.© 2019 The Author(s).Published by Oxford University Press on behalf of the Royal Astronomical Society, JB acknowledges support from the CONICYT-Chile grants Basal-CATA PFB-06/2007 & AFB-170002, FONDECYT Postdoctorados 3160439 and the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. This research was supported by the DFG cluster of excellence 'Origin and Structure of the Universe'. GY would like to thank MINECO/FEDER for financial support under project grant AYA2015-63810-P. MK acknowledges support from DLR grant 50OR1802. The CosmoSim data base is a service of the Leibniz-Institute for Astrophysics Potsdam (AIP). The MultiDark data base was developed in cooperation with the Spanish MultiDark Consolider Project CSD2009-00064.

The XMM-RM project was designed to provide X-ray coverage of the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) field. 41 XMM-Newton exposures, placed surrounding the Chandra AEGIS field, were taken, covering an area of 6.13 deg^2 and reaching a nominal exposure depth of ~15 ks. We present an X-ray catalog of 3553 sources detected in these data, using a PSF-fitting algorithm and a sample selection threshold that produces a ~5% fraction of spurious sources. In addition to the PSF-fitting likelihood, we calculate a second source reliability measure based on Poisson theory using source and background counts within an aperture. Using the Poissonian likelihood, we select a sub-sample with a high purity and find that it has similar number count profiles to previous X-ray surveys. The Bayesian method "NWAY" was employed to identify counterparts of the X-ray sources from the optical Legacy and the IR unWISE catalogs, using a 2-dimensional unWISE magnitude-color prior created from optical/IR counterparts of Chandra X-ray sources. A significant number of the optical/IR counterparts correspond to sources with low detection likelihoods, proving the value of retaining the low-likelihood detections in the catalog. 932 of the XMM-RM sources are covered by SDSS spectroscopic observations. 89% of them are classified as AGN, and 71% of these AGN are in the SDSS-RM quasar catalog. Among the SDSS-RM quasars, 80% are detectable at the depth of the XMM observations., Comment: ApJS accepted. 20 pages, 16 figures

An empirical forward-modeling framework is developed to interpret the multi-wavelength properties of Active Galactic Nuclei (AGN) and provide insights into the overlap and incompleteness of samples selected at different parts of the electromagnetic spectrum. The core of the model are observationally derived probabilites on the occupation of galaxies by X-ray selected AGN. These are used to seed mock galaxies drawn from stellar-mass functions with accretion events and then associate them with spectral energy distributions that describe both the stellar and AGN emission components. This approach is used to study the complementarity between X-ray and WISE mid-infrared AGN selection methods. We first show that the basic observational properties of the X-ray and WISE AGN (magnitude, redshift distributions) are adequately reproduced by the model. We then infer the level of contamination of the WISE selection and show that this is dominated by non-AGN at redshifts $z, full article at https://arxiv.org/abs/2009.00060

Supplemental material, Online_Supplement for The Curse of Extremes: Generalist Career Experience and CEO Initial Compensation by Philipp E.M. Mueller, Dimitrios Georgakakis, Peder Greve, Simon Peck and Winfried Ruigrok in Journal of Management

The High Luminosity upgrade for the Large Hadron Collider LHC (HL-LHC) requires new Nb3Sn superconducting magnets and it triggers a development of novel hardware for the quench detection system (QDS) based on a field programmable gate array (FPGA) digital platform and a number of individually isolated analogue front-ends. Galvanic insulation has been implemented downstream the analogue to digital convertors to eliminate a usage of analogue isolation amplifiers. This concept was already successfully implemented in the current LHC QDS system, however the mitigation of new phenomena inside Nb3Sn materials required development of a new generation of QDS. The newly developed universal QDS offers flexibility of firmware defined architecture. Adopted prototype driven strategy includes thorough characterization of the analogue front-ends in the laboratory and prototype unit measurements performed on HL-LHC magnet prototypes at CERN's superconducting magnet test facility SM18. The tests also reveal the characteristics of the magnets as well as the measurement electronics at an early stage. The test results are used to optimize the analogue input stages as well as the digital signal processing within the FPGA. The preliminary test results are presented and focus is given to the measurement and studies of the so-called “flux jumps” to mitigate the effects of these voltage perturbations in the QDS.

Are new CEOs with diverse career experience more likely to promote strategic change early after their appointment? We attempt to address this question by integrating seemingly opposing predictions in the managerial cognition literature. We argue that new CEOs with high and low levels of intra-personal experience diversity will promote higher strategic change early after taking charge – compared to those at relatively moderate levels. Analyzing 115 CEO successions, we find support for the theorized U-shaped relationship between intra-personal CEO experience diversity and strategic change. Furthermore, our results suggest that this relationship is influenced by post-CEO-succession TMT turnover. We contribute to the literature on strategic change by adding a more nuanced perspective to the emerging research on new CEO career experience diversity, and its effects on corporate strategy.

We study the effect of new CEO succession origin on strategic change in firms facing turnaround situations. Taking a ‘relational perspective’ of CEO succession, we argue that the degree to which ou...

The statistical distributions of active galactic nuclei (AGNs), i.e., accreting supermassive black holes (BHs), in mass, space, and time are controlled by a series of key properties, namely, the BH-galaxy scaling relations, Eddington ratio distributions, and fraction of active BH (duty cycle). Shedding light on these properties yields strong constraints on the AGN triggering mechanisms while providing a clear baseline to create useful mock catalogs for the planning of large galaxy surveys. Here we delineate a robust methodology to create mock AGN catalogs built on top of large N-body dark matter simulations via state-of-the-art semiempirical models. We show that by using as independent tests the AGN clustering at fixed X-ray luminosity, galaxy stellar mass, and BH mass, along with the fraction of AGNs in groups and clusters, it is possible to significantly narrow down the choice in the relation between BH mass and host galaxy stellar mass, the duty cycle, and the average Eddington ratio distribution, delivering well-suited constraints to guide cosmological models for the coevolution of BHs and galaxies. Avoiding such a step-by-step methodology inevitably leads to strong degeneracies in the final mock catalogs, severely limiting their usefulness in understanding AGN evolution and in survey planning and testing.

THALES - European Union [383549]; Greek Government of the programme 'Education and lifelong learning'; FONDECYT Postdoctorados [3160439]; Ministry of Economy, Development, and Tourism's Millennium Science Initiative [IC120009]; Millennium Institute of Astro-physics MAS; Alfred P. Sloan Foundation; National Science Foundation; U.S. Department of Energy Office of Science; University of Arizona; Brazilian Participation Group; Brookhaven National Laboratory; Carnegie Mellon University; University of Florida; French Participation Group; German Participation Group; Harvard University; Instituto de Astrofisica de Canarias; Michigan State/Notre Dame/JINA Participation Group; Johns Hopkins University; Lawrence Berkeley National Laboratory; Max Planck Institute for Astrophysics; Max Planck Institute for Extraterrestrial Physics; New Mexico State University; New York University; Ohio State University; Pennsylvania State University; University of Portsmouth; Princeton University; Spanish Participation Group; University of Tokyo; University of Utah; Vanderbilt University; University of Virginia; University of Washington; Yale University

Herein a techno-economic assessment was performed on an energy-crop-based biogas plant coupled with a greenhouse for utilizing thermal energy produced by cogeneration. Seven energy crops were evaluated: triticale, maize, alfalfa, sunflower, clover, barley and wheat. According to the evaluation, triticale was the most competitive energy crop under selected climate conditions for northern Greece. Although maize displays higher biomass yield and biogas potential than the drought-resistant crop triticale, it has high irrigation demand that contributes significantly to total production costs. For a triticale-based biogas production to become economically feasible, agricultural arable area larger than 500 ha, or biogas plant size larger than 1000 kWel, is required. However, with public funding, biogas production becomes feasible at smaller area (>250 ha) or biogas plant size (>500 kWel). The inclusion of a greenhouse into the design of the biogas plant contributes positively to the economic viability of the entire system. Under this scenario, greenhouse financial income accounts for about 17–18% of total income. Results of a sensitivity analysis suggest that the selection of an appropriate energy crop for biogas production should be based principally on both digestibility (specific methane yield) and biomass yield per hectare, these factors being more critical than biomass production costs.