Design of effective kernels for spectroscopy and molecular transport: time-dependent current-density-functional theory

Time-dependent current-density-functional theory (TDCDFT) provides an in principle exact scheme to calculate efficiently response functions for a very broad range of applications. However, the lack of approximations valid for a range of parameters met in experimental conditions has so far delayed its extensive use in inhomogeneous systems. On the other side, in many-body perturbation theory (MBPT) accurate approximations are available, but at a price of a higher computational cost. In the present work the possibility of combining the advantages of both approaches is exploited. In this way an exact equation for the exchange-correlation kernel of TDCDFT is obtained, which opens the way for a systematic improvement of the approximations adopted in practical applications. Finally, an approximate kernel for an efficient calculation of spectra of solids and molecular conductances is suggested and its validity discussed

Il conflitto (si', ancora il conflitto!) di interessi degli amministratori di s.p.a.: tra la rivendicazione di un ruolo attivo all'amministratore interessato ed il ridimensionamento dell'istanza di collegialita'

Il lavoro si volge a considerare alcuni profili della disciplina di cui all’art. 2391 c.c. Il primo capitolo muove dalla definizione di «maggior rigore» che si rinviene nella Relazione al d.lgs. 6/2003, per evidenziare i profili di criticità della regolamentazione previgente rilevati in dottrina ed approdare infine a considerazioni in ordine al modello di disciplina delineato dalla novella. Il secondo capitolo considera criticamente il preteso ampliamento quantitativo della fattispecie, per sottolineare la perdurante centralità del conflitto di interessi (non già solo al livello della ratio della disciplina, ma altresì) ai fini dell’individuazione della nozione di interesse rilevante. Quindi, rilevata la necessità di evitare un’eccessiva dilatazione dell’ambito operativo della disciplina, si dà conto di alcuni possibili percorsi che possano guidare l’interprete in tal direzione. Per rimarcare, da ultimo, la sussistenza in capo all’amministratore interessato di un ineliminabile ruolo nel sondare la praticabilità delle anzidette vie. Il terzo capitolo si appunta sull’obbligo di astensione dell’amministratore delegato, di cui si evidenzia la non operatività nell’ipotesi in cui l’interesse rilevante faccia capo non già al delegato stesso, bensì ad altro amministratore: dal che consegue una significativa erosione della postulata riserva di collegialità delle operazioni interessate

Challenges and prospects of the new banking resolution regime

The Florence School of Banking & Finance is a European platform bringing together practitioners and academics from the Banking and Finance sector to develop a common culture of regulation and supervision in the European Union.The consequences of the new banking resolution regime on the evolution of the European financial system were discussed at a Chatham House ‘Executive Seminar on Banking Resolution’ organized by the Florence School of Banking and Finance and held in Florence on 14-15 July 2016. The executive seminar brought together academics, EU policy-makers, investors, and industry practitioners to discuss the impact of the new resolution regime on banks, regulators and investors. Participants also exchanged views on liquidity support and exit strategies in the upcoming resolution phase. The main conclusions stemming from the interaction among panelists are the following: 1. Most of the systemic institutions still need to improve their internal governance in order to be in line with what is considered international best practice; 2. Despite some criticisms and unresolved issues, bail-in represents a clear and radical improvement from the government bail-outs that followed the Eurozone crisis; 3. Information disclosure to large investors is a major upcoming challenge posed by resolution; 4. A deeper assessment of the liquidity available for resolution needs to be carried out

Interested Voting

Corporate law is attentive to transactions with a controlling shareholder, but such transactions hardly cover all instances in which an interested shareholder may harm the corporation by casting a pivotal vote to pass a resolution. Interested votes cast by directors, managers, acquirers, cross-holders, arbitrageurs, institutional investors, hedge funds, and several other actors can be as detrimental as votes by a controlling shareholder. Yet, despite the ever growing influence of shareholders in corporate governance, interested voting has received scant attention. This Article is the first to offer a systematic mapping of interested voting based on type of shareholder and type of resolution. It categorizes existing policy approaches on interested voting as bright line rules (which discount votes presumed interested ex ante) or as open ended standards (which provide remedies for votes found ex post to be interested), and characterizes as “anything goes” the approach that leaves shareholders free to vote whichever way they please. Aside from policing controlling shareholders and, to a lesser extent, acquirers in M&A transactions, the law does not offer any remedies in several areas in which interested voting might occur, thus setting “anything goes” as the default regime for voting by non controlling shareholders. This Article evaluates whether and to what extent this “anything goes” regime is worrisome. While in some fields, like director elections and shareholder proposals, such an approach has the merit of limiting litigation rents, it is problematic in many others. In particular, M&A and other high profile financial transactions subject to shareholder approval run the risk of being determined by an interested voter not aligned with the genuine preferences of disinterested shareholders. Deal data show that half of (the few) close merger votes pass because of votes by insiders. In these cases, deal outcomes might systematically be swayed by votes at odds with the common interests of shareholders and market failures would ensue. This is troublesome given the current phase of reconcentration of ownership of public corporations, which makes it easier than ever to assemble coalitions of repeat players such as insiders, institutional investors, and hedge funds. If left unchecked, “anything goes” might result in a reduction of wealth in the long run

Effect of sensitization on the electrochemical properties of nanostructured NiO

Screen-printed NiO electrodes were sensitized with 11 different dyes and the respective electrochemical properties were analyzed in a three-electrode cell with the techniques of cyclic voltammetry and electrochemical impedance spectroscopy. The dye sensitizers of NiO were organic molecules of different types (e.g., squaraines, coumarins, and derivatives of triphenyl-amines and erythrosine B), which were previously employed as sensitizers of the same oxide in dye-sensitized solar cells of p-type (p-DSCs). Depending on the nature of the sensitizer, diverse types of interactions occurred between the immobilized sensitizer and the screen-printed NiO electrode at rest and under polarization. The impedance data recorded at open circuit potential were interpreted in terms of two different equivalent circuits, depending on the eventual presence of the dye sensitizer on the mesoporous electrode. The fitting parameter of the charge transfer resistance through the electrode/electrolyte interface varied in accordance to the differences of the passivation action exerted by the various dyes against the electrochemical oxidation of NiO. Moreover, it has been observed that the resistive term RCT associated with the process of dark electron transfer between the dye and NiO substrate is strictly correlated to the overall efficiency of the photoconversion () of the corresponding p-DSC, which employs the same dye-sensitized electrode as photocathode

The role of non-local exchange in the electronic structure of correlated oxides

We present a systematic study of the electronic structure of several prototypical correlated transition-metal oxides: VO2, V2O3, Ti2O3, LaTiO3, and YTiO3. In all these materials, in the low-temperature insulating phases the local and semilocal density approximations (LDA and GGA) of density-functional theory yield a metallic Kohn-Sham band structure. Here we show that, without invoking strong-correlation effects, the role of non-local exchange is essential to cure the LDA/GGA delocalization error and provide a band-structure description of the electronic properties in qualitative agreement with the experimental photoemission results. To this end, we make use of hybrid functionals that mix a portion of non-local Fock exchange with the local LDA exchange-correlation potential. Finally, we discuss the advantages and the shortcomings of using hybrid functionals for correlated transition-metal oxides.Comment: submitte

Leadership in Singleton Congestion Games: What is Hard and What is Easy

We study the problem of computing Stackelberg equilibria Stackelberg games whose underlying structure is in congestion games, focusing on the case where each player can choose a single resource (a.k.a. singleton congestion games) and one of them acts as leader. In particular, we address the cases where the players either have the same action spaces (i.e., the set of resources they can choose is the same for all of them) or different ones, and where their costs are either monotonic functions of the resource congestion or not. We show that, in the case where the players have different action spaces, the cost the leader incurs in a Stackelberg equilibrium cannot be approximated in polynomial time up to within any polynomial factor in the size of the game unless P = NP, independently of the cost functions being monotonic or not. We show that a similar result also holds when the players have nonmonotonic cost functions, even if their action spaces are the same. Differently, we prove that the case with identical action spaces and monotonic cost functions is easy, and propose polynomial-time algorithm for it. We also improve an algorithm for the computation of a socially optimal equilibrium in singleton congestion games with the same action spaces without leadership, and extend it to the computation of a Stackelberg equilibrium for the case where the leader is restricted to pure strategies. For the cases in which the problem of finding an equilibrium is hard, we show how, in the optimistic setting where the followers break ties in favor of the leader, the problem can be formulated via mixed-integer linear programming techniques, which computational experiments show to scale quite well