Relativistic plasmas in AGN jets - From synchrotron radiation to γ\gamma-ray emission

Relativistic jets of plasma are a key ingredient of many types of Active Galactic Nuclei (AGN). Today we know that AGNs are powered by the accretion of inter stellar material into the gravitational field of a Super Massive Black Hole and that this process can release as much power as a whole galaxy, like the Milky Way, from a region that is comparable to the Solar System in size. Depending on the properties of the central energy source, a large fraction of this power can be involved in the acceleration of magnetized plasmas at relativistic speeds, to form large scale jets. The presence of jets affects the spectrum of AGNs through the emission of synchrotron radiation and Inverse Compton scattering of low energy photons, thus leading to a prominent non-thermal spectrum, some times extending from radio frequencies all the way up to $\gamma$-ray energies. Here we review some characteristic processes of radiation emission in AGN jets, which lead to the emission of photons in the radio, optical, X-ray and $\gamma$-ray bands, and we present the results of a spectroscopic campaign of optical counterparts. We discuss our observations and their connection with $\gamma$-ray properties in a scenario that traces the role of relativistic jets in different classes of AGNs, detected both in the local as well as in the remote Universe.Comment: 11 pages, 5 figures (3 in color), proceedings of the XXVIII School on Physics of Ionized Gases (SPIG), accepted for publication on the European Journal of Physics

Generation of an ultrastable 578 nm laser for Yb lattice clock

In this paper we described the development and the characterization of a 578 nm laser source to be the clock laser for an Ytterbium Lattice Optical clock. Two independent laser sources have been realized and the characterization of the stability with a beat note technique is presente

Behavioural operations in healthcare : knowledge sharing perspective

Purpose The purpose of this paper is to provide arguments and empirical evidence that different knowledge sharing behaviours – i.e. sharing best practices, sharing mistakes, seeking feedbacks – are promoted and enabled by different types of knowledge assets, and differently affect employees’ innovative work behaviours. Design/methodology/approach The research framework includes four sets of constructs: employees’ innovative work behaviour, knowledge sharing, knowledge assets, psychological safety. The literature-grounded hypotheses were tested collecting data from healthcare professionals from three hospice and palliative care organisations in Italy. In all, 195 questionnaires were analysed using structural equations modelling technique. Findings First, findings show that the linkage between knowledge assets and knowledge sharing is both direct and indirect with psychological safety as relevant mediating construct. The linkage between relational and structural social capital and seeking feedbacks and sharing mistakes is fully mediated by psychological safety. Second, findings show that each dimension of knowledge sharing affects the different dimensions of employees’ innovative work behaviour – i.e. idea generation, idea promotion, idea implementation – in a distinct manner. While sharing of best practices influences all of them, seeking feedbacks affects idea promotion and sharing mistakes influences idea implementation. Practical implications The results provide operations managers with a clearer picture of how to pursue improvements of current operations by leveraging on knowledge sharing among employees through the creation of numerous, high-quality interpersonal relationships among employees, based on rich and cohesive network ties. Originality/value This study, by adopting a micro-level perspective, offers an original perspective on how knowledge assets and knowledge sharing initiatives may contribute to the engagement of innovative work behaviour by employees

The intrinsic Baldwin effect in broad Balmer lines of six long-term monitored AGNs

We investigate the intrinsic Baldwin effect (Beff) of the broad H$\alpha$ and H$\beta$ emission lines for six Type 1 active galactic nuclei (AGNs) with different broad line characteristics: two Seyfert 1 (NGC 4151 and NGC 5548), two AGNs with double-peaked broad line profiles (3C 390.3 and Arp 102B), one narrow line Seyfert 1 (Ark 564), and one high-luminosity quasar with highly red asymmetric broad line profiles (E1821+643). We found that a significant intrinsic Beff was present in all Type 1 AGNs in our sample. Moreover, we do not see strong difference in intrinsic Beff slopes in different types of AGNs which probably have different physical properties, such as inclination, broad line region geometry, or accretion rate. Additionally, we found that the intrinsic Beff was not connected with the global one, which, instead, could not be detected in the broad H$\alpha$ or H$\beta$ emission lines. In the case of NGC 4151, the detected variation of the Beff slope could be due to the change in the site of line formation in the BLR. Finally, the intrinsic Beff might be caused by the additional optical continuum component that is not part of the ionization continuum.Comment: 12 pages, 8 figures, Accepted for publication in A&

Prove di tossicità da S C P nell'ovino: nota 7.: rilievi sul comportamento della microflora ruminale

During chronic and acute toxicity trials on ovines, fed with an alkanegrown SCP, observations were also made on the behaviour of the ruminaI microflora. The different diet supplied to both experimental and control groups of animals, did not seem to have affected the total count and the total numbers of Starch digesters, Cellulose digesters and Proteolytic bacteria. During the chronic toxicity test, 194 strains of yeast were identified belonging to the following species: Candida boidinii, Candida slooffii, Candida tropicalis, Cryptococcus albidus var. albidus, Cryptococcus albidus var. diffluens, Cryptococcus dimennae, Cryptococcus kuetzingii, Rhodotorula glutinis var. dairenensis, Rhodotorula glutinis var. glutinis, Rhodotorula graminis, Rhodotorula pallida, Rhodotorula rubra, Torulopsis versatilis, Trichosporon cutaneum, Debaryomyces hansenii, Debaryomyces phaffi, Debaryomyces tamarii, Saccharomyces vafer . The yeast species that were isolated were not so different from those discovered by other authors in similar researches, carried cut, however, in animals fed differently. A marked diffusion of the genus Debaryomyces was to be observed, together with a notable lipolytic and caseinolytic activity in most of the strains isolated. At first the introduction of SCP in the diet at concentrations of 15% and 40% seemed to favour the multiplication of the yeasts in the rumen fluid, but their numbers diminished towards the end of both test in all groups under observation. The type of protein given, does not seem to have affected even the species of yeasts that are usually lodged in the animals rumen. Screening of the isolated strains is now in course for the SCP production on glucose, lactose, xylose, starch, fruit and citrus pulps, and other conventional substrata

Analisi chimiche

Le indagini chimiche eseguite presso il Centro di Spettroscopia(SS) tendevano (innanzitutto) ad accertare la la provenienza e il tipo d'impasto argilloso utilizzato per la fabbricazione delle ceramiche

Frequency transfer via a two-way optical phase comparison on a multiplexed fiber network

We performed a two-way remote optical phase comparison on optical fiber. Two optical frequency signals were launched in opposite directions in an optical fiber and their phases were simultaneously measured at the other end. In this technique, the fiber noise was passively cancelled, and we compared two optical frequencies at the ultimate 1E-21 stability level. The experiment was performed on a 47 km fiber that is part of the metropolitan network for Internet traffic. The technique relies on the synchronous measurement of the optical phases at the two ends of the link, that is made possible by the use of digital electronics. This scheme offers several advantages with respect to active noise cancellation, and can be upgraded to perform more complex tasks

Azidated Ether-Butadiene-Ether Block Copolymers as Binders for Solid Propellants

Polymeric binders for solid propellants are usually based on hydroxyl-terminated polybutadiene (HTPB), which does not contribute to the overall energy output. Azidic polyethers represent an interesting alternative but may have poorer mechanical properties. Polybutadiene–polyether copolymers may combine the advantages of both. Four different ether-butadiene-ether triblock copolymers were prepared and azidated starting from halogenated and/or tosylated monomers using HTPB as initiator. The presence of the butadiene block complicates the azidation step and reduces the storage stability of the azidic polymer. Nevertheless, the procedure allows modifying the binder properties by varying the type and lengths of the energetic blocks

Models of emission line profiles and spectral energy distributions to characterize the multi-frequency properties of active galactic nuclei

The spectra of Active Galactic Nuclei (AGNs) are often characterized by a wealth of emission lines with different profiles and intensity ratios that led to a complicated classification. Their electro-magnetic radiation spans more than 10 orders of magnitude in frequency. In spite of the differences between various classes, the origin of their activity is attributed to a combination of emitting components, surrounding an accreting Super Massive Black Hole, in the so called Unified Model. Currently, the execution of sky surveys, with instruments operating at various frequencies, provides the possibility to detect and to investigate the properties of AGNs on very large statistical samples. Thanks to the spectroscopic surveys that allow investigation of many objects, we have the opportunity to place new constraints on the nature and evolution of AGNs. In this contribution we present the results obtained by working on multi-frequency data and we discuss their relations with the available optical spectra. We compare our findings with the AGN Unified Model predictions, and we present a revised technique to select AGNs of different types from other line emitting objects. We discuss the multi-frequency properties in terms of the innermost structures of the sources.Comment: 11 pages, 4 figures. Proceedings of the XI Serbian Conference on Spectral Line Shapes in Astrophysics. Accepted for publication on Atom