Junction of three off-critical quantum Ising chains and two-channel Kondo effect in a superconductor

We show that a junction of three off-critical quantum Ising chains can be regarded as a quantum spin chain realization of the two-channel spin-1/2 overscreened Kondo effect with two superconducting leads. We prove that, as long as the Kondo temperature is larger than the superconducting gap, the equivalent Kondo model flows towards the 2 channel Kondo fixed point. We argue that our system provides the first controlled realization of 2 channel Kondo effect with superconducting leads. This, besides its the theoretical interest, is of importance for potential applications to a number of context, including the analysis of the quantum entanglement properties of a Kondo system.Comment: 14 pages, 4 .eps figure

Josephson versus Kondo coupling in a quantum dot connected to two superconductors

We apply a Gutzwiller-like variational technique to study Josephson conduction across a quantum dot with an odd number of electrons connected to two superconducting leads. Our method projects out all states on the dot but the Kondo singlet and is valid when Kondo correlations are dominant and no Andreev bound states localized at the dot are available for Kondo screening. In these conditions superconducting pairing is a competing effect and the junction is $\pi -$like, to optimize antiferromagnetic correlations on the dot. As the superconducting gap increases, the Josephson current also increases, but its phase dependence becomes strongly non sinusoidal

General purpose readout board {\pi} LUP: overview and results

This work gives an overview of the PCI-Express board $\pi$LUP, focusing on the motivation that led to its development, the technological choices adopted and its performance. The $\pi$LUP card was designed by INFN and University of Bologna as a readout interface candidate to be used after the Phase-II upgrade of the Pixel Detector of the ATLAS and CMS experiments at LHC. The same team in Bologna is also responsible for the design and commissioning of the ReadOut Driver (ROD) board - currently implemented in all the four layers of the ATLAS Pixel Detector (Insertable B-Layer, B-Layer, Layer-1 and Layer-2) - and acquired in the past years expertise on the ATLAS readout chain and the problematics arising in such experiments. Although the $\pi$LUP was designed to fulfill a specific task, it is highly versatile and might fit a wide variety of applications, some of which will be discussed in this work. Two 7$^{th}$-generation Xilinx FPGAs are mounted on the board: a Zynq-7 with an embedded dual core ARM Processor and a Kintex-7. The latter features sixteen 12.5$\,$Gbps transceivers, allowing the board to interface easily to any other electronic board, either electrically and/or optically, at the current bandwidth of the experiments for LHC. Many data-transmission protocols have been tested at different speeds, results will be discussed later in this work. Two batches of $\pi$LUP boards have been fabricated and tested, two boards in the first batch (version 1.0) and four boards in the second batch (version 1.1), encapsulating all the patches and improvements required by the first version.Comment: 6 pages, 10 figures, 21th Real Time Conference, winner of "2018 NPSS Student Paper Award Second Prize

L'elettrolisi: un'occasione per riflettere sulla Chimica, ma anche sulla storia, l'economia, l'ambiente

Pensiamo che partire da esempi tratti dal mondo che ci circonda, in cui le procedure della Chimica, sia teoriche che sperimentali, appaiano in tutto il loro intreccio con le attività umane, possa costituire un metodo efficace per fornire a vari livelli un’immagine della disciplina corretta. Ciò può aiutare ad approcciarsi ad essa senza paure e senza trionfalismi. Nell’articolo in particolare si tratteranno alcuni significativi processi di elettrolisi, evidenziando il loro sviluppo storico e le loro implicazioni dal punto di vista produttivo e del rapporto con uomo e ambiente.We believe that an effective way to provide, at various levels, a correct image of Chemistry could be based on examples from the world around us, in which the procedures of the discipline, both theoretical and experimental, appear in all their interweaving with human activities. This may help to approach it without fear and without triumphalism. In the article in particular we discuss some significant electrolysis processes, highlighting their his- torical development and their implications from the point of view of production and the rela- tionship with man and environment

Classification Trees for Ordinal Responses in R: The rpartScore Package

This paper introduces rpartScore (Galimberti, Soffritti, and Di Maso 2012), a new R package for building classification trees for ordinal responses, that can be employed whenever a set of scores is assigned to the ordered categories of the response. This package has been created to overcome some problems that produced unexpected results from the package rpartOrdinal (Archer 2010). Explanations for the causes of these unexpected results are provided. The main functionalities of rpartScore are described, and its use is illustrated through some examples

Human parvovirus B19 and blood product safety. A tale of twenty years of improvements

Parvovirus B19 (B19V), long known to be the causative agent of erythema infectiosum (fifth disease), is not a newly emerging agent. The aim of this review is to analyse the role played by this virus in compromising safety in transfusion medicine and the progressive measures to reduce the risks associated with the virus

La diagnostica per la conoscenza storica e artistica delle opere d'arte. Il ruolo delle analisi sui pigmenti nel restauro degli affreschi di Michelangelo nella Cappella Sistina

Il pensiero inerente la tutela delle opere d’arte ha subito una notevole evo- luzione nel corso della storia ed oggi è diventato indispensabile affiancare la scienza della conservazione alle consuete metodologie di restauro. Le scienze applicate ai Beni Culturali coinvolgono studiosi provenienti da diversi campi di ricerca e la collaborazione diventa una prerogativa imprescindibile per il successo dell’intervento conservativo e, soprattutto, per la conoscenza approfondita dell’opera in tutti i suoi aspetti, dai materiali costitutivi alla tecnica di realizzazione. Nell’articolo illustreremo quanto detto soffermandoci tra l’altro sul restauro degli affre- schi di Michelangelo della Cappella Sistina. Questo è stato definito come il primo restauro moderno, proprio perché le analisi hanno accompagnato ogni intervento tecnico sugli affre- schi, i quali sono tornati allo splendore originario nel rispetto dei principi teorici del restauro. In questo e in altri casi la diagnostica è diventata quindi un importante ausilio per lo stu- dio dei Beni Culturali, anche se la scelta della tecnica analitica deve essere relazionata sempre alla domanda alla quale si cerca la risposta. Le scienze applicate permettono di approfondire la storia dell’opera, la tecnica dell’artista, caratterizzano i materiali, ricostruendone le antiche rotte commerciali; tutte queste informazioni permettono di raggiungere una conoscenza senza pari, indispensabile per la valorizzazione, la tutela e la conservazione dei Beni Culturali.he approach to the protection of artwork has considerably evolved through- out history; placing side by side the conservation science and the usual methods of restoration has today become unavoidable. Science Applied to Cultural Heritage involves scholars from different research fields making their collaboration of paramount importance for the success of the conservation process and, above all, for the in-depth knowledge of the artwork in all its aspects, from the constituent materials to the realization technique. This article will discuss this topic taking into particular account the restoration of Michelangelo’s frescoes in the Sistine Chapel. This was defined as the first modern restoration, because scientific tests have accompanied for the first time any technical intervention on the frescoes, which were returned to their original splendor in respect of the theoretical principles of restoration. In this specific case and in other ones, the diagnostics has therefore become an important aid in Cultural Heritage studies, provided that the choice of the analytical technique is always related to the answer that one is trying to pursue. Applied sciences provide an insight into the history of the artworks, the artists’ techniques, the knowledge of employed materials – that allow one to reconstruct the ancient trade routes; all this information can accomplish an unsurpassed knowledge, which is becoming essential for the development, protection and conservation of Cultural Heritage