Multi-line Stokes inversion for prominence magnetic-field diagnostics

We present test results on the simultaneous inversion of the Stokes profiles of the He I lines at 587.6 nm (D_3) and 1083.0 nm in prominences (90-deg scattering). We created datasets of synthetic Stokes profiles for the case of quiescent prominences (B<200 G), assuming a conservative value of 10^-3 of the peak intensity for the polarimetric sensitivity of the simulated observations. In this work, we focus on the error analysis for the inference of the magnetic field vector, under the usual assumption that the prominence can be assimilated to a slab of finite optical thickness with uniform magnetic and thermodynamic properties. We find that the simultaneous inversion of the two lines significantly reduces the errors on the inference of the magnetic field vector, with respect to the case of single-line inversion. These results provide a solid justification for current and future instrumental efforts with multi-line capabilities for the observations of solar prominences and filaments.Comment: 14 pages, 5 figures, 1 tabl

The effects of the covid-19 pandemic on the mass market retailing of wine in Italy

The purpose of this study was to provide a detailed framework of wine purchases in supermarkets during the COVID-19 pandemic. The unexpected diffusion of the virus and the restrictions imposed in Italy to prevent its spread have significantly affected the food purchasing habits of consumers. By analyzing the scanner data of the wine sales in the Italian mass market retail channel, this study was intended to show whether and how the dynamics triggered by the pandemic have modified the overall value and type of wine purchases, focusing on prices, formats, and promotional sales. In particular, this study explores sales in two separate periods, namely March–April (the “lockdown”, with general compulsory closing and severe restrictions) and June–July 2020 (the “post-lockdown”, in which some limitations were no longer effective). The analysis of wine sales during lockdown and post-lockdown and the study of the variations compared to the sales of the previous years showed some significant changes in purchase behavior. The results could provide managers, researchers, and policy makers with extensive insights into the purchasing patterns of consumers during this unprecedented time and reveal trends that may characterize the structure of the future wine demand

Unsaturated hydraulic conductivity of a silty sand with the instantaneous profile method

The unsaturated hydraulic conductivity of a silty sand at different initial void ratios is measured using the instantaneous profile method. The variation of the suction and volumetric water content is recorded during the infiltration process as a function of time. Accordingly, an infiltration column was developed with a height of 600 mm and an inner diameter of 170 mm. The suction and volumetric water content were measured simultaneously every 100 mm along the column by means of small tensiometers and TDRs, respectively. Hydraulic conductivity is calculated by dividing the water flow velocity by the hydraulic gradient. The soil is reconstituted from Ruedlingen (Canton Schaffhausen, Switzerland), where landslide triggering experiments were carried out in October 2008 and March 2009. The hydraulic conductivity functions are determined and the laboratory values are compared to the in-situ measurements of hydraulic conductivity carried out in the course of the landslide triggering experiments

Space and Time pattern of mid-velocity IMF emission in peripheral heavy-ion collisions at Fermi energies

The emission pattern in the V_perp - V_par plane of Intermediate Mass Fragments with Z=3-7 (IMF) has been studied in the collision 116Sn + 93Nb at 29.5 AMeV as a function of the Total Kinetic Energy Loss of the reaction. This pattern shows that for peripheral reactions most of IMF's are emitted at mid-velocity. Coulomb trajectory calculations demonstrate that these IMF's are produced in the early stages of the reaction and shed light on geometrical details of these emissions, suggesting that the IMF's originate both from the neck and the surface of the interacting nuclei.Comment: 4 pages, 3 figures, RevTex 3.1, submitted to Phys. Rev. Letter

Bi-partite entanglement entropy in massive (1+1)-dimensional quantum field theories

This paper is a review of the main results obtained in a series of papers involving the present authors and their collaborator J L Cardy over the last 2 years. In our work, we have developed and applied a new approach for the computation of the bi-partite entanglement entropy in massive (1+1)-dimensional quantum field theories. In most of our work we have also considered these theories to be integrable. Our approach combines two main ingredients: the 'replica trick' and form factors for integrable models and more generally for massive quantum field theory. Our basic idea for combining fruitfully these two ingredients is that of the branch-point twist field. By the replica trick, we obtained an alternative way of expressing the entanglement entropy as a function of the correlation functions of branch-point twist fields. On the other hand, a generalization of the form factor program has allowed us to study, and in integrable cases to obtain exact expressions for, form factors of such twist fields. By the usual decomposition of correlation functions in an infinite series involving form factors, we obtained exact results for the infrared behaviours of the bi-partite entanglement entropy, and studied both its infrared and ultraviolet behaviours for different kinds of models: with and without boundaries and backscattering, at and out of integrability

Relative entropy and the Bekenstein bound

Elaborating on a previous work by Marolf et al, we relate some exact results in quantum field theory and statistical mechanics to the Bekenstein universal bound on entropy. Specifically, we consider the relative entropy between the vacuum and another state, both reduced to a local region. We propose that, with the adequate interpretation, the positivity of the relative entropy in this case constitutes a well defined statement of the bound in flat space. We show that this version arises naturally from the original derivation of the bound from the generalized second law when quantum effects are taken into account. In this formulation the bound holds automatically, and in particular it does not suffer from the proliferation of the species problem. The results suggest that while the bound is relevant at the classical level, it does not introduce new physical constraints semiclassically.Comment: 12 pages, 1 figure, minor changes and references adde

Comparison between the in situ and laboratory water retention curves for a silty sand

After an extreme rainfall event in May 2002 a series of landslides occurred in Ruedlingen in Canton Schaffhausen, North Switzerland. A 38° steep slope has been chosen in this area beside the river Rhine to carry out an artificial rainfall experiment to investigate the dependence between rainfall, suction, saturation and shear resistance. Two sprinkling experiments were conducted to represent an extreme rainfall event, the second of which resulted in failure of 130 m 3 of the slope. Several cycles of wetting and drying were applied to the soil and suction and volumetric water content were measured at different depths in three locations of the slope, by which in-situ Water Retention Curves (WRC) can be derived. The WRC of an undisturbed sample was also determined from laboratory test. The in situ and laboratory WRCs are compared in this paper and the differences will be discussed

Interpretation of the behaviour of compacted soils using cam-clay extended to unsaturated conditions

This paper is focused on the interpretation of experimental results obtained at the Department of Geotechnical Engineering of the University of Naples Federico II (Italy) to investigate the effects of partial saturation on the volumetric behaviour and the initial shear stiffness of a compacted silt. Tests were performed by using suction-controlled triaxial and resonant column cells. Herein, the compatibility of the results with a Single Stress Model (SSM) is discussed. The SSM allows to highlight that suction can have two effects on the mechanical behaviour of an unsaturated soil: it increases the average volumetric stress acting on the soil skeleton and it has a sort of cementing effect on the soil packing (hardening and cementation)

Application to a compacted soil of a Cam Clay model extended to unsaturated conditions

This paper presents an interpretation of experimental results obtained at the Department of Geotechnical Engineering of the Università di Napoli Federico II. The results are part of an extensive program carried out to investigate the effects of partial saturation on the volumetric behaviour and on the initial shear stiffness of a compacted silt. Tests were performed using two suction-controlled devices, a triaxial cell and a Resonant Column Torsional Shear (RCTS) cell. The compatibility of experimental data with a Bishop Stress Model (BSM) is discussed in the paper. The BSM permits to highlight the two main effects of suction on soil behaviour: the increase of the average stress acting on the soil skeleton and the hardening - cementing of the soil packing. Hydraulic hysteresis is included in the definition of the water retention curve so that its effects, such as the irreversible component of volume change recorded during drying paths, are automatically incorporated in the predictions of the model

Triaxial tests on frozen ground: formulation and modelling

Artificial Ground Freezing (AGF) is a controllable process that can be used by engineers to stabilise temporarily the ground, provide structural support and/or exclude groundwater from an excavation until construction of the final lining provides permanent stability and water tightness. In this work, the process of ground freezing is studied using a constitutive model that encompasses frozen and unfrozen behaviour within a unified effective-stress- based framework and employs a combination of ice pressure, liquid water pressure and total stress as state variables. The parameters of the constitutive model are calibrated against experimental data obtained from samples retrieved during construction of Napoli underground, in which AGF was extensively used to excavate in granular soils and weak fractured rock below the ground water table.Postprint (published version