Radiative transition rates and collision strengths for Si II

Aims. This work reports radiative transition rates and electron impact excitation collision strengths for levels of the 3s23p, 3s3p2, 3s24s, and 3s23d configurations of Siii. Methods. The radiative data were computed using the Thomas-Fermi-Dirac-Amaldi central potential, but with the modifications introduced by Bautista (2008) that account for the effects of electron-electron interactions. We also introduce new schemes for the optimization of the variational parameters of the potential. Additional calculations were carried out with the Relativistic Hartree-Fock and the multiconfiguration Dirac-Fock methods. Collision strengths in LS-coupling were calculated in the close coupling approximation with the R-matrix method. Then, fine structure collision strengths were obtained by means of the intermediate-coupling frame transformation (ICFT) method which accounts for spin-orbit coupling effects. Results. We present extensive comparisons between the results of different approximations and with the most recent calculations and experiment available in the literature. From these comparisons we derive a recommended set of gf- values and radiative transition rates with their corresponding estimated uncertainties. We also study the effects of different approximations in the representation of the target ion on the electron-impact collision strengths. Our most accurate set of collision strengths were integrated over a Maxwellian distribution of electron energies and the resulting effective collision strengths are given for a wide range of temperatures. Our results present significant differences from recent calculations with the B-spline non-orthogonal R-matrix method. We discuss the sources of the differences.Comment: 6 figures, 5 tables within text, 2 electronic table

Ionic Capillary Evaporation in Weakly Charged Nanopores

Using a variational field theory, we show that an electrolyte confined to a neutral cylindrical nanopore traversing a low dielectric membrane exhibits a first-order ionic liquid-vapor pseudo-phase-transition from an ionic-penetration "liquid" phase to an ionic-exclusion "vapor" phase, controlled by nanopore-modified ionic correlations and dielectric repulsion. For weakly charged nanopores, this pseudotransition survives and may shed light on the mechanism behind the rapid switching of nanopore conductivity observed in experiments.Comment: This version is accepted for publication in PR

AN INTEGRATED APPROACH TO PREVENT THE EROSION OF SALT MARSHES IN THE LAGOON OF VENICE

The loss of coastal habitats is a widespread problem in Europe. To protect the intertidal salt marshes of the lagoon of Venice from the erosion due to natural and human causes which is diffusely and intensely impacting them, the European Commission has funded the demonstrative project LIFE VIMINE. LIFE VIMINE aims to protect the most interior, hard-to-access salt marshes in the northern lagoon of Venice through an integrated approach, whose core is the prevention of erosion through numerous, small but spatially-diffuse soil-bioengineering protections works, mainly placed through semi-manual labour and with low impact on the environment and the landscape. The effectiveness of protection works in the long term is ensured through routine, temporally-continuous and spatially-diffuse actions of monitoring and maintenance. This method contrasts the common approach to managing hydraulic risk and erosion in Italy which is based on large, one-off and irreversible protection actions. The sustainability of the LIFE VIMINE approach is ensured by the participatory involvement of stakeholders and the recognition that protecting salt marshes means defending the benefits they provide to society through their ecological functions, as well as protecting the jobs linked to the existence or conservation of this habitat

Conflated Constructs: Disentangling the Educative and Evaluative Functions of Preservice Teacher Supervision

University mentors require specialized knowledge and skill to support teacher candidate learning in the context of fieldwork. Without such knowledge and skill, interactions between university mentors and teacher candidates is often evaluative, thus undermining the educative potential of mentoring. We focus on mentoring practices employed in the context of the post-observation conference. Findings from a year-long implementation study show that when university mentors are introduced to an educative mentoring protocol and are provided with sustained professional development, their mentoring practices shift from an evaluative to an educative focus. University mentors indicate that this shift, initially perceived as unnatural, was supported through the scaffolding provided by the protocol and on-going professional development. Shifts in university mentors’ practices supported teacher candidate reflection and growth. By foregrounding the educative function, this work adds to the theory-based conceptualization of the knowledge and skills needed for the effective mentoring of those learning to teach

Evaluation of the burden of HPV-related hospitalizations as a useful tool to increase awareness: 2007–2017 data from the sicilian hospital discharge records

In light of the implementation of human papillomavirus (HPV) prevention strategies, epidemiological studies in different geographical areas are required in order to assess the impact of HPV-related diseases. The purpose of the present study was to describe the burden of HPV-related hospitalizations in Sicily. A retrospective observational study estimated 43,531 hospitalizations attributable to HPV from 2007 to 2017. During the observed period, there was a decrease for all HPV-related conditions with a higher reduction, among neoplasms, for cervical cancer (annual percent change (APC) = −9.9%, p < 0.001). The median age for cervical cancer was 45 years old, with an increasing value from 43 to 47 years (p < 0.001). The age classes with greater decreases in hospital admissions for invasive cancers were women aged 35 years or more (APC range from −5.5 to −9.86) and 25–34 years old (APC = −11.87, p < 0.001) for women with cervical carcinoma in situ. After ten years for vaccine introduction and sixteen years for cervical cancer screening availability, a relatively large decrease in hospital admissions for cervical cancer and other HPV-related diseases in Sicily was observed. Some clinical characteristics of hospitalization, such as increasing age, are suggestive clues for the impact of preventive strategies, but further research is needed to confirm this relationship

Design methodologies for one way spanning eccentrically loaded minimally or centrally reinforced pre-cast RC panels

AbstractThis paper examines and evaluates design methodologies applicable to pre-cast reinforced concrete (RC) panels subjected to eccentric axial load. Theoretical capacities derived from existing regulatory guidance are compared against those determined from experimental investigations, showing that slender RC walls have load capacities significantly higher than the estimates based on current design equations.A simple computational procedure incorporating lumped plasticity is presented and experimentally validated. It is shown that by utilising a non-linear hinge at the critical cross section, it is possible to effectively simulate the buckling response of the slender walls considered with a modest computational effort. The proposed design strategy emerges as a viable alternative to traditional methodologies by being able to capture the main effects of geometrical and material nonlinearities. It is therefore suggested that this approach, used in conjunction with a probabilistic, semi-empirical design procedure, will lead to design capacities more representative of actual experimental findings

Variational approach for electrolyte solutions: from dielectric interfaces to charged nanopores

A variational theory is developed to study electrolyte solutions, composed of interacting point-like ions in a solvent, in the presence of dielectric discontinuities and charges at the boundaries. Three important and non-linear electrostatic effects induced by these interfaces are taken into account: surface charge induced electrostatic field, solvation energies due to the ionic cloud, and image charge repulsion. Our variational equations thus go beyond the mean-field theory. The influence of salt concentration, ion valency, dielectric jumps, and surface charge is studied in two geometries. i) A single neutral air-water interface with an asymmetric electrolyte. A charge separation and thus an electrostatic field gets established due to the different image charge repulsions for coions and counterions. Both charge distributions and surface tension are computed and compared to previous approximate calculations. For symmetric electrolyte solutions close to a charged surface, two zones are characterized. In the first one, with size proportional to the logarithm of the coupling parameter, strong image forces impose a total ion exclusion, while in the second zone the mean-field approach applies. ii) A symmetric electrolyte confined between two dielectric interfaces as a simple model of ion rejection from nanopores. The competition between image charge repulsion and attraction of counterions by the membrane charge is studied. For small surface charge, the counterion partition coefficient decreases with increasing pore size up to a critical pore size, contrary to neutral membranes. For larger pore sizes, the whole system behaves like a neutral pore. The prediction of the variational method is also compared with MC simulations and a good agreement is observed.Comment: This version is accepted for publication in Phys. Rev. E

Association of the Individual and Context Inequalities on the Breastfeeding: A Study from the Sicily Region

Despite the advantages of breastfeeding being widely recognized, the economic level can have an influence on breastfeeding rates, with rich women breastfeeding longer than poor in high-income countries. In Italy, socio-economic differences affect breastfeeding start and continuation among most deprived people, such as in Southern Italy. The objective of the study was to evaluate the prevalence of the initiation and continuation of exclusive breastfeeding and its association with the levels of socio-economic deprivation in Sicily. A prospective cohort study with a two-phase survey in three breastfeeding detection times was conducted. Overall, 1,055 mothers were recruited with a mean age of 31 years. Breastfeeding decreased from 86% during hospitalization to 69% at the first month and 42% at the sixth month, yet at the same time, exclusive breastfeeding increased from 34% to 38% during hospitalization to the first month and went down to 20.2% at the sixth month. The adjusted multivariate analysis showed no association with individual inequalities. On the other hand, the context inequalities had a significant association with the risk of not following exclusive breastfeeding in the deprived class (odds ratio (OR): 2.08, confidence interval (CI) 95% 1.01-4.27) and in the very deprived class (OR: 1.83, CI 95% 1.00-3.38) at the six-month survey. These results indicate that the context inequalities begin to emerge from the return home of the mother and the child