Two- versus three-dimensional connectivity testing of first-order queries to semi-algebraic sets

This paper addresses the question whether one can determine the connectivity of a semi-algebraic set in three dimensions by testing the connectivity of a finite number of two-dimensional ``samples'' of the set, where these samples are defined by first-order queries. The question is answered negatively for two classes of first-order queries: cartesian-product-free, and positive one-pass.Comment: corrected minor confusion in Proof of Theorem

Intermolecular Pauli repulsion: a QMC study of molecules in ground and excited state in free space and in solution

In this work we present a method to compute the Pauli repulsion interaction energy between two molecules and for a molecule solvated by a discrete medium. The method of Amovilli and Mennucci, that has been developed within a continuum solvent model approach, is here revised in order to treat the solvation environment with a discrete number of solvent molecules. In our model, one of the two interacting systems, and the solvent in the case of solvation, acts as ‘probe’. A probe has a volume domain defined by the atomic spheres centred on the nuclei of the relevant molecule. The probe measures the fraction of electrons of the solute molecule falling in its domain leading to the evaluation of Pauli repulsion energy. To this end, Quantum Monte Carlo calculations are used to sample the electronic configurations of the solute. The method has been designed to be applied also to excited states. We show results for test systems in the ground state and for the ground and the (Formula presented.) excited states of acetone in a cluster with 14 water molecules

Shannon Entropy in Atoms: A Test for the Assessment of Density Functionals in Kohn-Sham Theory

Electron density is used to compute Shannon entropy. The deviation from the Hartree-Fock (HF) of this quantity has been observed to be related to correlation energy. Thus, Shannon entropy is here proposed as a valid quantity to assess the quality of an energy density functional developed within Kohn-Sham theory. To this purpose, results from eight different functionals, representative of Jacob's ladder, are compared with accurate results obtained from diffusion quantum Monte Carlo (DMC) computations. For three series of atomic ions, our results show that the revTPSS and the PBE0 functionals are the best, whereas those based on local density approximation give the largest discrepancy from DMC Shannon entropy

Electronic, dynamical and superconducting properties of CaBeSi

We report first-principles calculations on the normal and superconducting state of CaBe(x)Si(2-x) (x=1), in the framework of density functional theory for superconductors (SCDFT). CaBeSi is isostructural and isoelectronic to MgB2 and this makes possible a direct comparison of the electronic and vibrational properties and the electron-phonon interaction of the two materials. Despite the many similarities with MgB2 (e.g. sigma bands at the Fermi level and a larger Fermi surface nesting), according to our calculations CaBeSi has a very low critical temperature (Tc ~ 0.4 K, consistent with the experiment). CaBeSi exhibits a complex gap structure, with three gaps at Fermi level: besides the two sigma and pi gaps, present also in MgB2, the appearance of a third gap is related to the anisotropy of the Coulomb repulsion, acting in different way on the bonding and antibonding electronic pi states.Comment: 6 pages, 5 figure

Intuitive perception and the competitive advantage of small family businesses: an exploratory study

We assess the closeness of perceptions between managers and customers of two small family-owned businesses ("FBs") and two larger non-FBs in Sardinia, Italy, in exploring how local retail shops may compete against international superstores. While the decline of small, High Street businesses has been widely reported, we present a more nuanced perspective of their competitiveness by suggesting how these typically family-run businesses may hold a competitive advantage over larger non-FBs based on their welldeveloped "perceptive concordance" with customers. Our findings have scholarly and managerial implications in the way that both FBs and non-FBs may gain competitive advantage by securing their customers' continuing support

Synthesis and Biological Activity of Novel Platencin Derivatives

The biological mode of action of platencin, a potential lead molecule for a new class of antibiotics, is detailed. Furthermore, enantiopure syntheses of several platencin derivatives are described, of which the core structure can be accessed in two exceedingly simple steps from commercially available starting materials. Furthermore, the antibiotic properties of the derivatives was evaluated

Depletion-mode Quantum Dots in Intrinsic Silicon

We report the fabrication and electrical characterization of depletion-mode quantum dots in a two-dimensional hole gas (2DHG) in intrinsic silicon. We use fixed charge in a SiO$_2$/Al$_2$O$_3$ dielectric stack to induce a 2DHG at the Si/SiO$_2$ interface. Fabrication of the gate structures is accomplished with a single layer metallization process. Transport spectroscopy reveals regular Coulomb oscillations with charging energies of 10-15 meV and 3-5 meV for the few- and many-hole regimes, respectively. This depletion-mode design avoids complex multilayer architectures requiring precision alignment, and allows to adopt directly best practices already developed for depletion dots in other material systems. We also demonstrate a method to deactivate fixed charge in the SiO$_2$/Al$_2$O$_3$ dielectric stack using deep ultraviolet light, which may become an important procedure to avoid unwanted 2DHG build-up in Si MOS quantum bits.Comment: Accepted to Applied Physics Letters. 5 pages, 3 figure

Deprotonative metalation of substituted aromatics using mixed lithium-cobalt combinations

International audienceThe deprotonation of anisole was attempted using different homo- and heteroleptic TMP/Bu mixed lithium-cobalt combinations. Using iodine to intercept the metalated anisole, an optimization of the reaction conditions showed that in THF at room temperature 2 equiv of base were required to suppress the formation of the corresponding 2,2'-dimer. The origin of the dimer was not identified, but its formation was favored with allyl bromide as electrophile. The metalated anisole was efficiently trapped using iodine, anisaldehyde, and chlorodiphenylphosphine, and moderately employing benzophenone, and benzoyl chloride. 1,2-, 1,3- and 1,4-dimethoxybenzene were similarly converted regioselectively to the corresponding iodides. It was observed that 2-methoxy- and 2,6-dimethoxypyridine were more prone to dimerization than the corresponding benzenes when treated similarly. Involving ethyl benzoate in the metalation-iodination sequence showed the method was not suitable to functionalize substrates bearing reactive functions

Dermatitis in community pharmacies: a survey on italian pharmacists’ management and implications on corticophobia

Community pharmacists represent an important resource for the promotion of a safer and more effective self-management of common skin diseases, as well as the provision of educational support on therapies prescribed by clinicians, ultimately improving patients’ adherence. In this study, a semi-structured survey was administered to 154 Italian community pharmacists, in order to acquire information on their counseling activity on dermatological disorders. Collected data provide an overview on the frequency and methodology of counseling offered in Italian community pharmacies, identifying knowledge gaps and misbeliefs. In particular, an overall negative opinion on topical corticosteroid therapy emerged among pharmacists, unveiling a phenomenon previously described as corticophobia. Starting from this observation, we discuss the risks for patients’ adherence, associated with corticophobia among pharmacists. Lastly, we briefly report on the main tools desired by pharmacists to improve their education on dermatology, envisioning their implementation with the aim of a more effective counseling