Nonequilibrium dynamics of spin-boson models from phase space methods

An accurate description of the nonequilibrium dynamics of systems with coupled spin and bosonic degrees of freedom remains theoretically challenging, especially for large system sizes and in higher than one dimension. Phase space methods such as the Truncated Wigner Approximation (TWA) have the advantage of being easily scalable and applicable to arbitrary dimensions. In this work we adapt the TWA to generic spin-boson models by making use of recently developed algorithms for discrete phase spaces [Schachenmayer, PRX 5, 011022 (2015)]. Furthermore we go beyond the standard TWA approximation by applying a scheme based on the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy of equations [Pucci, PRB 93, 174302 (2016)] to our coupled spin-boson model. This allows in principle to study how systematically adding higher order corrections improves the convergence of the method. To test various levels of approximation we study an exactly solvable spin-boson model which is particularly relevant for trapped-ion arrays. Using TWA and its BBGKY extension we accurately reproduce the time evolution of a number of one- and two-point correlation functions in several dimensions and for arbitrary number of bosonic modes.Comment: 10+5 pages, 5 figure

UN MODELLO ALLE DIFFERENZE FINITE DI UN PANNELLO FOTOVOLTAICO ACCOPPIATO A MATERIALE A CAMBIAMENTO DI FASE

La diffusione commerciale dei dispositivi fotovoltaici presenta negli ultimi anni un trend di crescita significativa a livello internazionale. Numerose ricerche sono state svolte al fine di incrementare l\u2019efficienza di conversione elettrica dei pannelli fotovoltaici e tra le soluzioni indagate \ue8 stato sperimentato l\u2019impiego di materiali a cambiamento di fase (MCF) per ridurre i picchi di temperatura di funzionamento. Nel lavoro \ue8 stato sviluppato un algoritmo di calcolo in grado di fornire l\u2019andamento temporale della temperatura di un pannello fotovoltaico accoppiato a materiale a cambiamento di fase (Sistema PV-MCF). La determinazione della distribuzione di temperature che interessano un sistema PV-MCF \ue8 stata affrontata con il metodo delle differenze finite in geometria monodimensionale. Sono state definite le equazioni di conservazione dell\u2019energia per ogni punto nodale in cui \ue8 stato discretizzato il sistema fisico, differenziandole per i nodi \u201cinterni\u201d e per i nodi \u201csuperficiali\u201d. Le equazioni alle differenze finite sono state formulate esplicitamente rispetto alla variabile temporale e sono state codificate in un apposito software. Il confronto con alcune soluzioni analitiche largamente impiegate nella bibliografia di settore ha permesso di verificare la correttezza e la validit\ue0 dell\u2019approccio sviluppato

Newborn body perception: sensitivity to spatial congruency

Studies on adults have demonstrated that the perception our own body can be manipulated by varying both temporal and spatial properties of multisensory information. While human newborns are capable of detecting the temporal synchrony of visuo-tactile body-related cues, it remains unknown whether they also utilise spatial information for body perception. Twenty newborns were presented with a video of an infant's face touched with a paintbrush, while their own face was touched either in the spatially congruent, or an incongruent, location. We found that newborns show a visual preference for spatially congruent synchronous events, supporting the view that newborns have a rudimentary sense of their own body

Healthcare Associated Infections. educational intervention by "Adult Learning" in an Italian teaching hospital

An educational intervention for HAI prevention based on a combination of training, motivation and subsequent application in the current clinical practice in an Italian teaching hospital

Nitrogen fertilization management in no-tillage maize with different witer crops.

The nitrogen (N) utilization by maize grown in a no-tillage system is dependent on the quality of the preceding crop residues, which may promote differences in N fertilization efficiency with respect to time. Thus, the purpose of this study was to evaluate the nutritional state, dry matter production and grain yield of maize grown in a clayey soil (Typic Acrustox) under a no-tillage system. The split-plot experimental design was set up in randomized complete blocks with three replications, in which the main plot was treated with different N application strategies and the split-plots were planted with winter crops (soybean and maize). The fertilizer strategies (rate: 120 kg ha-1 of N) used were as follows: (0 ? 0), (20 ? 100), (60 ? 60), (120 ? 0) and (0 ? 120), with the first number corresponding to the rate of N (kg ha-1) applied before planting and the second number corresponding to the top dressing rate (V4-5 stage). Nitrogen fertilization raised the N content (in shoots and leaves) and maize yield (in the shoot dry matter and grain). The maize grown after soybean had both greater N concentrations and production (dry matter and grain) relative to the maize grown after maize. Applying 120 kg ha-1 N did not significantly affect the evaluated variables, regardless of the winter crop

In vitro metabolism of a nitroderivative of acetylsalicylic acid (NCX4016) by rat liver: LC and LC-MS studies

The metabolism of a nitroderivative of acetylsalicylic acid, benzoic acid, 2-(acetyloxy)-3-[(nitrooxy)methyl]phenyl ester (NCX4016), the lead compound of a new class of NO-releasing non steroidal-antiinflammatory drugs has been studied in vitro in rat liver subcellular fractions (S 9000xg, microsomes, cytosol). Samples were extracted with CH3CN (2 vol.) containing 1% H3PO4 (2 M), vortexed for 3 min and then centrifuged for 5 min at 5000 rpm. Supernatants were diluted with 0.02 M phosphoric acid and analysed by reverse-phase LC. Linearity of calibration for NCX4016 and metabolites was observed over the range 0.25-50 microg/ml with coefficients of determination greater than 0.9996. Extraction efficiency from spiked liver samples ranged from 85 to 95% for all the analytes. In the S 9000xg fraction, NCX4016 undergoes rapid metabolization, with the formation of salicylic acid (SA) and [3-(nitrooxymethyl)phenol] (HBN). HBN is then rapidly metabolised to 3-hydroxybenzylalcohol (HBA), and mainly to a new metabolic species, whose formation takes place specifically in the liver cell cytosol. LC-MS analysis (electrospray ionisation) of the cytosol extract in negative and positive-ion modes furnished deprotonated [M-H]- and protonated [M+H]+ molecular ions at m/z 412 and 414, respectively, accompanied by the typical clusters with sodium. MS/MS analysis in negative-ion mode, by selection and collision of the ion at m/z 412, gave a fragmentation pattern characterized by the ions at m/z 272 and 254, which allowed to assign the structure of 1-(glutathion-S-yl)methylene-3-hydroxy-benzene, a conjugated product between GSH and the benzyl carbon atom of HBN. In rat liver cytosol HBN is completely metabolised to this thioether adduct within 30 min incubation; the process is enzymatically mediated by GSH transferase and strictly dependent on GSH availability. The relevance of this new metabolic pathway in NCX4016 detoxification by rat liver is discussed