The emergence of classical behavior in magnetic adatoms

A wide class of nanomagnets shows striking quantum behavior, known as quantum spin tunneling (QST): instead of two degenerate ground states with opposite magnetizations, a bonding-antibonding pair forms, resulting in a splitting of the ground state doublet with wave functions linear combination of two classically opposite magnetic states, leading to the quenching of their magnetic moment. Here we study how QST is destroyed and classical behavior emerges in the case of magnetic adatoms, as the strength of their coupling, either to the substrate or to each other, is increased. Both spin-substrate and spin-spin coupling renormalize the QST splitting to zero allowing the environmental decoherence to eliminate superpositions between classical states, leading to the emergence of spontaneous magnetization.Comment: 5 pages, 4 figure

AA-stacked bilayer square ice between graphene layers?

Water confined between two layers with separation of a few Angstrom forms layered two- dimensional ice structure. Using large scale molecular dynamics simulations with the adoptable ReaxFF interatomic potential we found that flat monolayer ice with a rhombic-square structure nucleates between graphene layers which is non-polar and non-ferroelectric. Two layers of water are found to crystallize into a square lattice close to the experimental found AA-stacking [G. Algara- Siller et al. Nature 519, 443445 (2015)]. Each layer has a net dipole moment which are in opposite direction. Bilayer ice is also non-polar and non-ferroelectric. For three layer ice we found that each layer has a crystal structure similar to monolayer ice

Lending relationships and credit rationing: the impact of securitization

Do lending relationships mitigate credit rationing? Does securitization influence the impact of lending relationships on credit rationing? If so, is its impact differently in normal periods versus crisis periods? This paper combines several unique data sets to address these questions. Employing a disequilibrium model to identify credit rationing, we find that more intense lending relationships, measured through their length and lower number, considerable improve credit supply and reduce the degree of credit rationing. In general, we find that a relationship with a bank that is more involved in securitization activities relaxes credit constraints in normal periods; however, it also increases credit rationing during crisis periods. Finally, we study the impact of different types of securitization – covered bonds and mortgage-backed securities (MBS) – on credit rationing. While both types of securitization reduce credit rationing in normal periods, the issuance of MBS by a firm’s main bank aggravates these firm’s credit rationing in crisis periods.lending relationships;financial crisis;securitization

Comparing Solution Methods for Dynamic Equilibrium Economies

This paper compares solution methods for dynamic equilibrium economies. We compute and simulate the stochastic neoclassical growth model with leisure choice using Undetermined Coefficients in levels and in logs, Finite Elements, Chebyshev Polynomials, Second and Fifth Order Perturbations and Value Function Iteration for several calibrations. We document the performance of the methods in terms of computing time, implementation complexity and accuracy and we present some conclusions about our preferred approaches based on the reported evidence.Dynamic Equilibrium Economies, Computational Methods, Linear and Nonlinear Solution Methods

Real-time reverse transcription polymerase chain reaction development for rapid detection of Tomato brown rugose fruit virus and comparison with other techniques

Background: Tomato brown rugose fruit virus (ToBRFV) is a highly infectious tobamovirus that causes severe disease in tomato (Solanum lycopersicum L.) crops. In Italy, the first ToBRFV outbreak occurred in 2018 in several provinces of the Sicily region. ToBRFV outbreak represents a serious threat for tomato crops in Italy and the Mediterranean Basin. Methods: Molecular and biological characterisation of the Sicilian ToBRFV ToB-SIC01/19 isolate was performed, and a sensitive and specific Real-time RT-PCR TaqMan minor groove binder probe method was developed to detect ToBRFV in infected plants and seeds. Moreover, four different sample preparation procedures (immunocapture, total RNA extraction, direct crude extract and leaf-disk crude extract) were evaluated. Results: The Sicilian isolate ToB-SIC01/19 (6,391 nt) showed a strong sequence identity with the isolates TBRFV-P12-3H and TBRFV-P12-3G from Germany, Tom1-Jo from Jordan and TBRFV-IL from Israel. The ToB-SIC01/19 isolate was successfully transmitted by mechanical inoculations in S. lycopersicum L. and Capsicum annuum L., but no transmission occurred in S. melongena L. The developed real-time RT-PCR, based on the use of a primer set designed on conserved sequences in the open reading frames3, enabled a reliable quantitative detection. This method allowed clear discrimination of ToBRFV from other viruses belonging to the genus Tobamovirus, minimising false-negative results. Using immunocapture and total RNA extraction procedures, the real-time RT-PCR and end-point RT-PCR gave the same comparable results. Using direct crude extracts and leaf-disk crude extracts, the end-point RT-PCR was unable to provide a reliable result. This developed highly specific and sensitive real-time RT-PCR assay will be a particularly valuable tool for early ToBRFV diagnosis, optimising procedures in terms of costs and time

Delimitação de zonas inundáveis entre Belver e Vila Nova da Barquinha

Só está disponível o resumo.Delimitação de zonas inundáveis entre Belver e Vila Nova da Barquinha