Metadynamic sampling of the free energy landscapes of proteins coupled with a Monte Carlo algorithm

Metadynamics is a powerful computational tool to obtain the free energy landscape of complex systems. The Monte Carlo algorithm has proven useful to calculate thermodynamic quantities associated with simplified models of proteins, and thus to gain an ever-increasing understanding on the general principles underlying the mechanism of protein folding. We show that it is possible to couple metadynamics and Monte Carlo algorithms to obtain the free energy of model proteins in a way which is computationally very economical.Comment: Submitted to Gen

L’innovazione nelle medie imprese bresciane. Un’indagine empirica

L’articolo presenta i risultati di una indagine empirica su un campione di medie imprese della provincia di Brescia con particolare riferimento all’innovazione di prodotto e di processo. Le evidenze empiriche sugli investimenti in ricerca e sviluppo, sull’innovazione di prodotto e processo e sugli investimenti in nuove tecnologie mostrano la presenza di un gruppo di promettenti medie imprese innovative. Ma in generale il sistema delle imprese della provincia di Brescia è ancora segnato da alcune debolezze, quali una innovazione prevalentemente incrementale e non basata sulla ricerca, un basso livello di investimenti in ricerca e sviluppo, una bassa qualità del capitale umano impiegato, un debole impegno alla protezione delle innovazioni introdotte. L’articolo inquadra queste debolezze nei limiti sia dimensionali e organizzativi delle imprese che culturali di sistema dell’imprenditorialità del territorio indagato

Room Temperature Organic Superconductor?

The electron--phonon coupling in fullerene C28 has been calculated from first principles. The value of the associated coupling constant lambda/N(0) is found to be a factor three larger than that associated with C60. Assuming similar values of the density of levels at the Fermi surface N(0) and of the Coulomb pseudopotential for C28-based solids as those associated with alkali-doped fullerides A3C60, one obtains Tc(C28) \approx 8 Tc(C60).Comment: 10 pages, 2 figure

The ability of the turnaround index to assess going concern assumptions: evidence from its application to Italian listed companies.

In times of crisis, entrepreneur often must decide whether to liquidate the company and the whole business or to renew it by activating a turnaround process. A tool increasingly used in international practice is the turnaround index, which can determine whether a company can continue its activities in the future according to the going concern assumption, which is the index measured as a function of the economic and financial performance of the company. This measure can take values between 0.1, for satisfactory performance and therefore unlikely to turn around, and 0.9, for unsatisfactory performance and therefore a high propensity to turnaround. The index determines whether there is a higher or lower risk for a company to enter into crisis. The aim of this paper is to test the effectiveness of the turnaround index in assessing the turnaround urgency by choosing a sample of the Italian companies

EVIDENCE OF THE ITALIAN SPECIAL PURPOSE ACQUISITION COMPANY

In 1992 David Nussbaum with the support of the law firm Graubard Miller devised the formula of the specified purpose acquisition companies (SPAC): a financial vehicle that has the flexibility and functionality typical of the blank-check companies, which could provide investors with the right protections and guarantees in order to be a reliable instrument. The first SPAC officially debuted in 2003 through the Initial Public Offering (IPO) of Millstream Acquisition Corporation which then completed the merger with Nations Health in September 2004. In 2005 the first SPAC got listed in European Market and in 2011 the first SPAC joined in the Italian market. The aim of this research is to investigate the features of the Italian SPACs System because it\u201fs becoming a large phenomenon in Italy. This new type of investment is able to fit the needs of small-medium Italian companies, to solve crisis difficulties, to find new finance to grow, to be a good instrument for opening up venture capital and institutional investors respecting the past business history and the safeguard of corporate control. The study, then, performs an analysis on the Italian SPACs by examining their target firms, stock performance before and after the business combination and the impact of the SPACs on SME corporate governance models. These results will be compared with those of other research developed by academic literature

A need for assurance: Do internal control systems integrate environmental, social, and governance factors?

In the article, we provide an original linkage between the corporate environmental, social, and governance (ESG) rating and the cost of internal control system (ICSC) stemmed from two closely related frameworks: the 2017 CoSO Framework, which calls to strengthen internal control systems to integrate ESG issues, and the EU directive on nonfinancial reporting (2014/95/EU) that entered into force in 2017. Thus, we evaluate both introductions showing ESG integration in the internal control activities. We cover firms listed on Milan Exchange from 2016 to 2019, providing a thorough analysis with robustness tests. The findings imply that firms should consider both ESG rating and the internal control system cost as strategic corporate tools for value enhancement; therefore, companies should allocate the resources appropriately to internal control activities to incorporate ESG issues and create value since internal control provides the first assurance for ESG integration. The limitations of this study pave the way for further research directions; incorporating the new amendment of the EU directive on nonfinancial disclosure, allowing for a better valuation creation assessment; and whether there is a substitution between sustainability performance and other corporate issues such as taxes and marketing expenditure

A folding inhibitor of the HIV-1 Protease

Being the HIV-1 Protease (HIV-1-PR) an essential enzyme in the viral life cycle, its inhibition can control AIDS. The folding of single domain proteins, like each of the monomers forming the HIV-1-PR homodimer, is controlled by local elementary structures (LES, folding units stabilized by strongly interacting, highly conserved, as a rule hydrophobic, amino acids). These LES have evolved over myriad of generations to recognize and strongly attract each other, so as to make the protein fold fast and be stable in its native conformation. Consequently, peptides displaying a sequence identical to those segments of the monomers associated with LES are expected to act as competitive inhibitors and thus destabilize the native structure of the enzyme. These inhibitors are unlikely to lead to escape mutants as they bind to the protease monomers through highly conserved amino acids which play an essential role in the folding process. The properties of one of the most promising inhibitors of the folding of the HIV-1-PR monomers found among these peptides is demonstrated with the help of spectrophotometric assays and CD spectroscopy

Aggregation of Dependent Risks with Specific Marginals by the Family of Koehler-Symanowski Distributions

Many problems in Finance, such as risk management, optimal asset allocation, and derivative pricing, require an understanding of the volatility and correlations of assets returns. In these cases, it may be necessary to represent empirical data with a parametric distribution. In the literature, many distributions can be found to represent univariate data, but few can be extended to multivariate populations. The most widely used multivariate distribution in the aggregation of dependent risks in a portfolio is the Normal distribution, which has the drawbacks of inflexibility and frequent inappropriateness. Here, we consider modelling assets and measuring portfolio risks using the family of Koehler-Symanowski multivariate distributions with specific marginals, as, for example, the generalized lambda distribution. This family of distributions can be defined using the cdf along with interaction terms in the independence case. This family can be derived using a particular transformation of exponential random variables and an independent gamma. This distribution has the advantage of allowing models with complex dependence structures, as we demonstrate with Monte Carlo simulations and the analysis of the risk of a portfolioRisk Management, Monte Carlo Method, Generalized Lambda Distribution, Koehler-Symanowski Distribution