3,488 research outputs found

    Nearby radio loud AGN and the Unified Model

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    The statistical study of the parsec scale properties of radio sources is crucial to get information on the nature of the central engine and to provide the foundations of the current unified theories, suggesting that the appearance of active galactic nuclei depends strongly on orientation. We started a project to observe at sub-arcsec resolution a complete sample of 94 nearby (z<0.1) radio galaxies, the Bologna Complete Sample, which is not affected by any selection effect on the jet velocity and orientation with respect to the line of sight. Up to now, we published our parsec scale analysis of 77/94 sources. Here, we describe the last VLBA observations at 5 GHz and EVN data at 18 cm obtained for the 17 remaining faintest radio core (<5 mJy at 5 GHz in VLA images) BCS sources and we report our preliminary results on the whole complete sample.Comment: 4 pages, 1 figure; accepted for publication in the proceeding of the "12th European VLBI Network Symposium and Users Meeting - EVN 2014" (7-10 October 2014, Cagliari, Italy); published online in Proceedings of Science, PoS(EVN 2014)09

    Twin SMBH candidates in the BCG of RBS 797

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    The radio-loud BCG at the center of the cool core cluster RBS 797 is known to exhibit a misalignment of its 5 GHz radio emission observed at different VLA resolutions, with the innermost kpc-scale jets being almost orthogonal to the radio lobes which extends for tens of kpc filling the X-ray cavities seen by Chandra. The different radio directions may be caused by rapid jet reorientation due to interaction with a secondary supermassive black hole (SMBH), or to the presence of two AGN, probably in a merging phase, which are emitting radio jets in different directions. We present the results of new 5 GHz observations performed with the EVN in May 2013. In particular, we detected two compact radio components, with a projected separation of 77 pc. We discuss two possible scenarios for the origin and nature of the EVN double source, showing that both interpretations are consistent with the presence of a SMBH binary system in the BCG of RBS 797.Comment: 4 pages, 1 figure; accepted for publication in the proceeding of the "12th European VLBI Network Symposium and Users Meeting - EVN 2014" (7-10 October 2014, Cagliari, Italy); published online in Proceedings of Science, PoS(EVN 2014)08

    Bioethanol in biofuels checked by an amperometric organic phase enzyme electrode (OPEE) working in “substrate antagonism” format

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    The bioethanol content of two samples of biofuels was determined directly, after simple dilution in decane, by means of an amperometric catalase enzyme biosensor working in the organic phase, based on substrate antagonisms format. The results were good from the point of view of accuracy, and satisfactory for what concerns the recovery test by the standard addition method. Limit of detection (LOD) was on the order of 2.5 × 10−5 M. © 2016 by the authors; licensee MDPI, Basel, Switzerland

    Innovative LOPA-based methodology for the safety assessment of chemical plants

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    The aim of the present work was the development and application of a methodology for the safety assessment of chemical plants based on LOPA (Layer of Protection Analysis) techniques. The approach integrates the use of consolidate hazard identification techniques (HazOp) and the adoption of quantitative literature models for consequence assessment (e.g., integral models) into the LOPA framework, allowing to limit the role played by expert judgment in the evaluation in order to reduce the causes of uncertainty in the results. Furthermore, a systematic and quantitative assessment of safety measures contribution to the reduction of plant residual risk was included in the analysis. In order to apply the methodology, a case study was defined taking into account an actual industrial facility. The results obtained allowed demonstrating the potentialities of the method

    Digital Archive as a Creative Booster.Connecting Design Processes to Logistics and PLM Platforms

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    Comparison between a direct-flow SPR immunosensor for ampicillin and a competitive conventional amperometric device: analytical features and possible applications to real samples

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    In this research, we developed a direct-flow surface plasmon resonance (SPR) immunosensor for ampicillin to perform direct, simple, and fast measurements of this important antibiotic. In order to better evaluate the performance, it was compared with a conventional amperometric immunosensor, working with a competitive format with the aim of finding out experimental real advantages and disadvantages of two respective methods. Results showed that certain analytical features of the new SPR immunodevice, such as the lower limit of detection (LOD) value and the width of the linear range, are poorer than those of a conventional amperometric immunosensor, which adversely affects the application to samples such as natural waters. On the other hand, the SPR immunosensor was more selective to ampicillin, and measurements were more easily and quickly attained compared to those performed with the conventional competitive immunosensor

    Synthesis and D<sub>2</sub>-like binding affinity of new derivatives of N3-[(1- ethyltetrahydro-1H-2-pyrrolyl)methyl]-4,5-dihydrobenzo[g]indole-3- carboxamide and related compounds

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    In previous papers 4a,b we have reported the syntheses and structure-activity relationships of a series of 5-phenyl-3-pyrrole carboxamide and related 4,5-dihydrobenzo[g]indole-3-carboxamide analogues whose most representative terms were 1a and 2a respectively. Encouraged by these results we carried out several modifications of 2a

    New Insight into a Deceptively Simple Reaction: The Coordination of bpy to RuII-Carbonyl Precursors - The Central Role of thefac-[Ru(bpy)Cl(CO)3]+Intermediate and theChloride Rebound Mechanism

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    This work demonstrates how a careful reexamination of well-trodden fields can fill conceptual gaps that previously escaped full understanding. The coordination of 2,2'-bipyridine (bpy) to the known Ru(II)-chlorido-carbonyl precursors \u2013 the dinuclear [RuCl2(CO)3]2 (P1) and the polymeric [RuCl2(CO)2]n (P2) \u2013 has been investigated by several groups in the past, and a remarkably large number of ruthenium mono(bpy) carbonyls were identified and fully characterized. Many were investigated as catalysts or key intermediates for the photochemical, electrochemical, and photo-electrochemical reduction of CO2, and for the water\u2013gas shift reaction. Nevertheless, even though most \u2013 if not all \u2013 the reaction products are known already, a careful exam of the literature led us to believe that a convincing general scheme interconnecting them all was still missing and important questions remained unanswered. For this reason, we investigated the reactivity of two mononuclear Ru(II)-carbonyl-dmso precursors, trans,cis,cis-[RuCl2(CO)2(dmso-O)2] (P3) and fac-[RuCl2(CO)3(dmso-O)] (P4) \u2013 that can be considered as \u2018activated forms\u2019 of P2 and P1, respectively \u2013 towards the coordination of bpy. Compounds P3 and P4, allowed us to gain new mechanistic insight and a deeper level of understanding. In particular, we found that coordination of bpy to P4 (or P1) generates first the tricarbonyl cation fac-[Ru(bpy)Cl(CO)3]+.This key intermediate undergoes the facile and selective nucleophilic attack on the CO trans to Cl (by RO\u2013 in alcoholic solvents or OH\u2013 from adventitious water in other solvents), leading to all other species. We also demonstrated that Cl\u2013 \u2013 even when in large excess \u2013 is unable to replace a carbonyl on fac-[Ru(bpy)Cl(CO)3]+. However, the chloride set free from the precursor, competes efficiently with bpy for the coordination to Ru(II) (chloride rebound mechanism)

    CALCAREOUS NANNOPLANKTON RESPONSE TO THE LATEST CENOMANIAN OCEANIC ANOXIC EVENT 2 PERTURBATION

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    Morphometric analyses were performed on Biscutum constans, Zeugrhabdotus erectus, Discorhabdus rotatorius and Watznaueria barnesiae specimens from five sections spanning the Cenomanian-Turonian boundary interval including Oceanic Anoxic Event (OAE) 2 (~ 94 Ma). The study provides evidence for size fluctuations and dwarfism of B. constans during OAE 2, followed by a partial recovery at the end of the event: this taxon appears to be the most sensitive species, with similar and coeval size trends in all the analyzed sections. Conversely, morphometry shows negligible or unsystematic coccolith variations in Z. erectus, D. rotatorius and W. barnesiae. The comparison of OAE 2 data with those available for the early Aptian OAE 1a and latest Albian OAE 1d, indicates that B. constans repeatedly underwent size reduction and temporary dwarfism possibly implying that the same paleoenvironmental factors controlled calcification of B. constans during subsequent OAEs although the amplitude of B. constans coccolith reduction is significantly larger for OAE 1a than OAE 2. Paleoceanographic reconstructions suggest that ocean chemistry related to the amount of CO2 and toxic metal concentrations played a central role in B. constans coccolith secretion, while temperature and nutrient availability do not seem to have been crucial. Contrary to OAE 1a, Z. erectus, D. rotatorius and W. barnesiae appear to be substantially unrelated to OAE 2 paleoenvironmental stress, possibly because of different degrees of perturbation.&nbsp; &nbsp
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