Il lobbying tra teorie e regolazione.

Regulation of the private interests’ influence in politics has been justified by economists through the market inefficiencies stemmed from rent-seeking activities. Although the rent-seeking theory offer a positive tool to calculate those inefficiencies, in this paper I argue that lobbying can enhance the legitimacy of a political system if those activities fell under mandatory and full disclosure of information about the actors involved, both politicians and lobbyists. Drawing from the insights of the public policy researches, in this paper I highlight how know the determinants of lobbying can help lobbying regulation to disseminate information about the political process. This goal can be reached just if the regulators are aware of the importance of transparency in the overall legitimacy of the political system

Studio di processi a più componenti coinvolgenti arini e sintesi ed elaborazione di adotti ottenuti attraverso reazioni di nitroso Diels-Alder

RIASSUNTO ANALITICO Il presente lavoro di tesi si è articolato in due parti: sviluppo di processi a più componenti coinvolgenti arini e sintesi ed elaborazioni di addotti ottenuti attraverso reazioni di nitroso Diels-Alder. Nella prima parte il nostro interesse si è focalizzato nell’addizione sequenziale di un nucleofilo ed un elettrofilo su arini generati attraverso ioni fluoruro: la componente nucleofila è stata selezionata fra gli alchini mentre la componente elettrofila ha visto lo screening di numerosi composti allilici. È stato utilizzato un sistema rame-ligante che porta nel primo stadio alla formazione di acetiluri di rame che attaccando l’arino formano aril cuprati che si addizionano all’elettrofilo allilico. I migliori risultati sono stati ottenuti con fenilacetilene e vinil aziridina dove la catalisi mediata dal sistema ioduro rameoso-PyBox favorisce l’apertura secondo un meccanismo SN2’. Il fluoruro di cesio è presente in eccesso perché è responsabile della generazione del benzino e della deprotonazione dell’alchino. Inizialmente era stata aggiunta un’ammina terziaria per favorire la deprotonazione ma è stato osservato che è sufficientemente nucleofila per attaccare l’arino con formazione di uno zwitterione. Questo dato ci ha portato a saggiare la reattività delle ammine terziarie a nucleofilicità crescente sul benzino osservando un processo di β-eliminazione di tipo Hoffman che porta alla sintesi di derivati anilinici. Lo studio si è espanso anche per ammine ibridate sp2 impiegando l’arino come attivante della posizione 2 di 4-metossipiridine (Schema 2). La seconda parte del lavoro si è concentrata sull’elaborazione della 2-carbossimetil 1,2-diidropiridina precedentemente sintetizzata nel mio laboratorio di tesi a seguito di una reazione di tipo Perkin acil Mannich tra anidride acetica e piridina. La diidropiridina è stata studiata impiegando una larga varietà di reazioni di tipo Diels-Alder. I risultati più interessanti sono stati ottenuti mediante la reazione di nitroso Diels-Alder. A seconda del nitroso derivato è stato possibile ottenere regioselettivamente addotti di tipo diretto, e inverso o una miscela 55:45. L’elaborazione dei cicloaddotti ha fornito in alcuni casi delle reattività molto interessanti. Ad esempio lo studio del cleavage del legame ossigeno-azoto degli N-acil cicloaddotti ha permesso l’individuazione di un nuova trasposizione [3.3] sigmatropica per fornire piperidine polifunzionalizzate non convenzionali. In un caso è stato possibile individuare le condizioni sperimentali per ottenere il cleavage dei cicloaddotti

Nonspinning black hole-neutron star mergers: a model for the amplitude of gravitational waveforms

Black hole-neutron star binary mergers display a much richer phenomenology than black hole-black hole mergers, even in the relatively simple case - considered in this paper - in which both the black hole and the neutron star are nonspinning. When the neutron star is tidally disrupted, the gravitational wave emission is radically different from the black hole-black hole case and it can be broadly classified in two groups, depending on the spatial extent of the disrupted material. We present a phenomenological model for the gravitational waveform amplitude in the frequency domain that encompasses the three possible outcomes of the merger: no tidal disruption, "mild", and "strong" tidal disruption. The model is calibrated to general relativistic numerical simulations using piecewise polytropic neutron star equations of state. It should prove useful to extract information on the nuclear equation of state from future gravitational-wave observations, and also to obtain more accurate estimates of black hole-neutron star merger event rates in second- and third-generation interferometric gravitational-wave detectors. We plan to extend and improve the model as longer and more accurate gravitational waveforms become available, and we will make it publicly available online as a Mathematica package. We also present in appendix analytical fits of the projected KAGRA noise spectral density, that should be useful in data analysis applications.Comment: 22 pages; 10 figures; 4 tables; a MATHEMATICA package is available at: http://www.phy.olemiss.edu/~berti/research.htm

In memory of Paolo Costantino (1955–2020)

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Aligned spin neutron star-black hole mergers: a gravitational waveform amplitude model

The gravitational radiation emitted during the merger of a black hole with a neutron star is rather similar to the radiation from the merger of two black holes when the neutron star is not tidally disrupted. When tidal disruption occurs, gravitational waveforms can be broadly classified in two groups, depending on the spatial extent of the disrupted material. Extending previous work by some of us, here we present a phenomenological model for the gravitational waveform amplitude in the frequency domain encompassing the three possible outcomes of the merger: no tidal disruption, "mild" and "strong" tidal disruption. The model is calibrated to 134 general-relativistic numerical simulations of binaries where the black hole spin is either aligned or antialigned with the orbital angular momentum. All simulations were produced using the SACRA code and piecewise polytropic neutron star equations of state. The present model can be used to determine when black-hole binary waveforms are sufficient for gravitational-wave detection, to extract information on the equation of state from future gravitational-wave observations, to obtain more accurate estimates of black hole-neutron star merger event rates, and to determine the conditions under which these systems are plausible candidates as central engines of gamma-ray bursts, macronovae and kilonovae.Comment: 15 pages, 7 figures, 1 tabl

Bile leak after elective laparoscopic cholecystectomy: Role of MR imaging

Increasing hepatobiliary laparoscopic surgeries have lead to a rise in injury to the biliary tree and other complications like bile leak. Ultrasonography (US) and computed tomography (CT) cannot reliably distinguish bile from other postoperative fluid collections. Magnetic resonance (MR) imaging with hepatobiliary agents and MR cholangiopancreatography provide anatomic and functional information that allows for prompt diagnosis and excludes any other concomitant complications. We report a case of post-cholecystectomy bile leak in a 42-year-old female who presented with persistent dull abdominal pain after the intervention; we emphasize the role of MR imaging in achieving the correct diagnosis

Reconsidering Generic Composition: the modes A10, A11 and A12 are insecure

Authenticated Encryption (AE) achieves privacy and authenticity with a single scheme. It is possible to obtain an AE scheme gluing together an encryption scheme (privacy secure) and a Message Authentication Code (authenticity secure). This approach is called generic composition and its security has been studied by Namprempre et al. [NRS14]. They looked into all the possible gluings of an encryption scheme with a secure MAC to obtain a nonce-based AE-scheme. The encryption scheme is either IV-based (that is, with an additional random input, the initialization vector [IV]) or nonce-based (with an input to be used once, the nonce). Nampremepre et al. assessed the security/insecurity of all possible composition combinations except for 4 (N4, A10, A11 and A12). Berti et al. [BPP18a] showed that N4 is insecure and that the remaining modes (A10, A11, and A12) are either all secure or insecure. Here, we prove that these modes are all insecure with a counterexample

Parallel and perpendicular cascades in solar wind turbulence

MHD-scale fluctuations in the velocity, magnetic, and density fields of the solar wind are routinely observed. The evolution of these fluctuations, as they are transported radially outwards by the solar wind, is believed to involve both wave and turbulence processes. The presence of an average magnetic field has important implications for the anisotropy of the fluctuations and the nature of the turbulent wavenumber cascades in the directions parallel and perpendicular to this field. In particular, if the ratio of the rms magnetic fluctuation strength to the mean field is small, then the parallel wavenumber cascade is expected to be weak and there are difficulties in obtaining a cascade in frequency. The latter has been invoked in order to explain the heating of solar wind fluctuations (above adiabatic levels) via energy transfer to scales where ion-cyclotron damping can occur. Following a brief review of classical hydrodynamic and magnetohydrodynamic (MHD) cascade theories, we discuss the distinct nature of parallel and perpendicular cascades and their roles in the evolution of solar wind fluctuations