7,688 research outputs found

    Stratosphere chemistry in a 2-D model with residual circulation

    Get PDF
    The objective of this research was to examine the effects of chemical perturbations on the stratosphere using models which can incorporate fully interactive radiative, chemical, and dynamical responses, in the context of a zonally averaged model. Model runs for the unperturbed, chlorine-perturbed and simultaneously chlorine-and CO2-perturbed cases were completed using the JPL-87 chemical kinetics data. The base case was analyzed and submitted for publication. The perturbed cases show substantial sensitivity of the predicted column ozone depletion to the perturbations affecting lower stratosphere temperature, but less to far dynamical perturbations. The column ozone distribution changed substantially when the kinetics data was changed. This implies a greater-than-expected uncertainty in predicted latitude distributions of ozone depletion, due to uncertainty about the accuracy and completeness of the chemical kinetics data set

    Report on the 2-D Model Intercomparison Workshop held January 11-16, 1987 in Fort Myers Beach, Florida, chapter 2

    Get PDF
    In the attempts to understand the processes which affect ozone in the stratosphere, and to predict future ozone levels, a variety of computer models were developed and employed. To oversimplify somewhat, the models range from 1-D models with intricately detailed photochemistry but only the crudest representation of transport, to 3-D general circulation models with intricately detailed dynamics and no photochemistry at all. Each of these has its appropriate uses. It was felt that there was much to be gained from intermediate models incorporating an extensive treatment of photochemistry with a dynamical framework which at least recognizes that atmospheric motions are advective as well as diffusive, and that both chemistry and dynamics are subject to latitudinal and seasonal variations. Thus the 2-D, zonally averaged models have begun to play a larger role in the last seven years, both in attempting to understand observed distributions of trace species and in attempting to assess the probable effects of antropogenic perturbations. There are many choices to be made in developing the model. It was the purpose of the 2-D model Intercomparison Workshop to permit discussion of the choices made and the behavior of the resulting models. The goal was not to identify a best set of choices, but rather to identify areas in which the models are sensitive to the choices made, and to develop a sense of where these models as a class do well or poorly in simulating the observed atmosphere

    Deprivation and kidney disease – a predictor of poor outcomes

    Get PDF
    There is a growing body of evidence for the role of deprivation in a broad spectrum of diseases including renal disease. Deprivation has been demonstrated to be associated with poorer outcomes across a range of renal diseases including acute kidney injury (AKI), chronic kidney disease and transplantation. In this issue of Clinical Kidney Journal, Hounkpatin et al. describe the association of socioeconomic deprivation with incidence, mortality and resolution of AKI in a large UK cohort. Investigating deprivation as a factor influencing either incidence or outcome of disease is challenging due to variations in measures of deprivation used and other confounding factors that may be contributing to the observed differences. In this editorial, we review the current literature examining the role of deprivation in renal disease

    Modelling the atomic structure of very high-density amorphous ice

    Full text link
    The structure of very high-density amorphous (VHDA) ice has been modelled by positionally disordering three crystalline phases, namely ice IV, VI and XII. These phases were chosen because only they are stable or metastable in the region of the ice phase diagram where VHDA ice is formed, and their densities are comparable to that of VHDA ice. An excellent fit to the medium range of the experimentally observed pair-correlation function g(r) of VHDA ice was obtained by introducing disorder into the positions of the H2O molecules, as well as small amounts of molecular rotational disorder, disorder in the O--H bond lengths and disorder in the H--O--H bond angles. The low-k behaviour of the experimental structure factor, S(k), is also very well reproduced by this disordered-crystal model. The fraction of each phase present in the best-fit disordered model is very close to that observed in the probable crystallization products of VHDA ice. In particular, only negligible amounts of ice IV are predicted, in accordance with experimental observation.Comment: 4 pages, 3 figures, 1 table, v2: changes made in response to referees' comments, the justification for using certain ice phases is improved, and ice IV is now disordered as wel

    Social report framing: Evidence from a major Italian bank

    Get PDF
    This study aims to analyse the development of a social report in a major Italian bank from its formation in 2007 to 2012.The Italian banking sector plays an important role in the Italian economy.Several Italian frameworks for social reports have been published and used by Italian companies.However, an important framework for social reports in Italy is the GRI.The paper aims to answer the following research questions: 1) what international guidelines have been used by the Bank in its social reports, during the period considered? 2) What have been the structural changes in the social report over time? The aim of these questions is to analyse the structure of the Bank’s six social reports.The paper relies on documentary analysis, applied to six social reports. It is based on G3 Guidelines and Performance Indicators (PIs).The paper finds that in the six-year period several changes in social reports are highlighted.We conclude that the Bank has engaged in a process of continuous improvement in the information content of the social report, including recently indicating that a PI is only partially disclosed if not in accordance with the guidelines
    corecore