3,425 research outputs found

    Scaling of Berry's Phase Close to the Dicke Quantum Phase Transition

    Full text link
    We discuss the thermodynamic and finite size scaling properties of the geometric phase in the adiabatic Dicke model, describing the super-radiant phase transition for an NN qubit register coupled to a slow oscillator mode. We show that, in the thermodynamic limit, a non zero Berry phase is obtained only if a path in parameter space is followed that encircles the critical point. Furthermore, we investigate the precursors of this critical behavior for a system with finite size and obtain the leading order in the 1/N expansion of the Berry phase and its critical exponent

    Capillary electrophoretic and extraction conditions for the analysis of Catha edulis FORKS active principles

    Get PDF
    A capillary electrophoretic method, which allowed the detection and separation of the active principles of Catha edulis, i.e. cathinone, cathine and phenylpropanolamine, was developed. A suitable internal standard (nicotinamide), which permitted the quantification of the analytes reducing the variability of the migration times due to EOF changes, was identified. The analytical method was validated, assessing linearity, sensitivity and repeatability, showing optimal features for the analysis of the vegetable material. Moreover extraction conditions were investigated to achieve the exhaustion of the plant material in the fastest and most efficient way to meet the requirements of the Court

    i rexfo life an innovative business model to reduce food waste

    Get PDF
    Abstract Every year the food produced and wasted consumes a volume of water equal to 250 km3, requires around 30% of the world agricultural land, and it is responsible for the emission of 3,3 billion tons of greenhouse gases. The direct economic consequences of food waste are ranging around 750 billion dollars per year (FAO source). i-REXFO designs an innovative business model with the objective of reducing significantly the amount of landfilled food waste. The actions are economically sustained by public incentives, tax reductions and private revenues from energy valorization of residual food waste. Uptaking the good practices from other EU countries (Denmark) the project will develop a tool to design the integrated model, optimize it from a technical, economic and environmental point of view and transfer it to other EU regions. i-REXFO will increase consumer awareness on food waste reduction in retail malls and HORECA while facilitating the sale and donation to charities and food banks of close to expiration and aesthetically not adequate food; it will also remove the barriers that hamper the use of food residues in biogas plants. The actions are economically sustained from energy valorization of food waste in biogas plant that use the digestate as fertilizer, closing the cycle. I-REXFO will achieve an overall reduction of 17000 tons/year of food waste landfilled during the project duration and in the after life phase. This will correspond to an overall reduction of 41000 tons of CO2 equivalent emissions

    Retrieval of characteristic parameters for water vapour transmittance in the development of ground based Sun-Sky radiometric measurements of columnar water vapour

    Get PDF
    Sunsky radiometers are instruments created for aerosol study, but they can measure in the water vapour absorption band allowing the estimation of columnar water vapour in clear sky simultaneously with aerosol characteristics, with high temporal resolution. A new methodology is presented for estimating calibration parameters (i.e. characteristic parameters of the atmospheric transmittance and solar calibration constant) directly from the sunsky radiometer measurements. The methodology is based on the hypothesis that characteristic parameters of the atmospheric transmittance are dependent on vertical profiles of pressure, temperature and moisture occurring at each site of measurement. To obtain the parameters from the proposed methodology some seasonal independent measurements of columnar water vapour taken over a large range of solar zenith angle simultaneously with the sunsky radiometer measurements, are needed. In this work high time resolution columnar water vapour measurements by GPS were used as independent data set, but also the case when such measurements are not available was considered by developing the surface humidity method (SHM). This methodology makes it possible to retrieve the needed independent data set of columnar water vapour using the standard surface meteorological observations (temperature, pressure and relative humidity) more readily available. The time pattern of columnar water vapour from sunsky radiometer retrieved using both the methodologies was compared with simultaneous measurements from microwave radiometer, radiosondings and GPS. Water vapour from sunsky radiometer, obtained using GPS independent measurements, was characterized by an error varying from 1% up to 5%, whereas water vapour from SHM showed an error from 1% up to 11%, depending on the local columnar water occurring at the site during the year. These errors were estimated by comparing water vapour series from sunsky radiometer against measurements taken by GPS at a nearby station. The accordance between retrievals from sunsky radiometer and simultaneous measurements from the other instruments was found always within the error both in the case of SHM and of the GPS independent data set. Water vapour obtained using characteristic parameters of the atmospheric transmittance dependent on water vapour was also compared against GPS retrievals, showing a clear improvement with respect to the case when these parameters are kept fixed

    Information, Credit, and Organization

    Get PDF
    This paper investigates the effect of a change in informational environment of borrowers on the organizational design of bank lending. We use micro-data from a large multinational bank and exploit the sudden introduction of a credit registry, an information-sharing mechanism across banks, for a subset of borrowers. Using within borrower and loan officer variation in a difference-in-difference empirical design, we show that expansion of credit registry led to an improvement in allocation of credit to affected borrowers. There was a concurrent change in the organizational structure of the bank that involved a dramatic increase in delegation of lending decisions of affected borrowers to loan officers. We also find a significant expansion in scope of activities of loan officers who deal primarily with affected borrowers, as well as of their superiors. There is suggestive evidence that larger banks in the economy were better able to implement similar changes as our bank. We argue that these patterns can be understood within the framework of incentive-based and information cost processing theories. Our findings could help rationalize why improvements in the information environment of borrowers may be altering the landscape of lending by moving decisions outside the boundaries of financial intermediaries

    SARS-CoV-2 mRNA Vaccine Breakthrough Infections in Fully Vaccinated Healthcare Personnel: A Systematic Review

    Get PDF
    The number of people vaccinated against COVID-19 increases worldwide every day; however, it is important to study the risk of breakthrough infections in vaccinated individuals at high risk of exposure such as healthcare personnel (HCP). A systematic literature review (SLR) applying the PRISMA declaration and the PECOS format using the following entry terms was used: “Health Personnel OR Healthcare Worker OR Healthcare Provider OR Healthcare Personnel AND breakthrough OR infection after vaccine*”. The research was carried out utilizing the following databases: SCOPUS, PubMed, Embase, and Web of Sciences. An overall very low incidence of post-vaccination breakthrough infections was found, ranging from 0.011 to 0.001 (per 100 individuals at risk). Our findings further support the published high effectiveness rates of mRNA vaccines in preventing SARS-CoV-2 infections among fully vaccinated HCP. Additional studies are needed to define the duration of the vaccine-induced protection among HCP

    How Do Laws and Institutions Affect Recovery Rates for Collateral?

    Get PDF
    Using unique internal bank data on ex ante appraised liquidation and market values of assets pledged as collateral in sixteen countries, we show that laws and institutions that strengthen creditor protection increase expected recovery rates for collateral. Stronger creditor protection increases expected recovery rates for movable collateral relative to immovable collateral and shifts the composition of collateral toward movable assets, thereby increasing debt capacity through both higher loan-to-values and attenuating the creditor's liquidation bias. Our results suggest that the recovery rate for collateral is an important first-stage mechanism through which creditor protection can improve contracting efficiency and enhance access to credit

    Ageing test of the ATLAS RPCs at X5-GIF

    Full text link
    An ageing test of three ATLAS production RPC stations is in course at X5-GIF, the CERN irradiation facility. The chamber efficiencies are monitored using cosmic rays triggered by a scintillator hodoscope. Higher statistics measurements are made when the X5 muon beam is available. We report here the measurements of the efficiency versus operating voltage at different source intensities, up to a maximum counting rate of about 700Hz/cm^2. We describe the performance of the chambers during the test up to an overall ageing of 4 ATLAS equivalent years corresponding to an integrated charge of 0.12C/cm^2, including a safety factor of 5.Comment: 4 pages. Presented at the VII Workshop on Resistive Plate Chambers and Related Detectors; Clermont-Ferrand October 20th-22nd, 200
    • …
    corecore