7,688 research outputs found
Stratosphere chemistry in a 2-D model with residual circulation
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
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
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
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
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Prioritizing IT Projects: An Empirical Application of an IT Investment Model
Information Technology projects are organizational investments that anticipate positive returns. When viewed as such, the development of a diversified “portfolio” of projects helps reduce risk from a single project failure, and results in an overall positive return. Positive returns on IT projects are usually indirect, since they have value only insomuch as they enable the accomplishment of larger organizational goals. We present here a model that integrates elements of risk, cost, and internal rate of return that can be applied to individual IT projects. The model produces a numerical score that can be used to rank potential IT projects. Projects with higher scores return more value to the organization, and therefore should be given a higher priority. We apply the model using the IT project portfolio of a large state-charterd credit union. The results indicated that the credit union was prioritizing projects with more visibility but lower returns that other projects with less visibility but that offered greater returns. The implications of applying the model in other organizational settings are discussed
Social report framing: Evidence from a major Italian bank
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
Effective Feedback to Improve Primary Care Prescribing Safety (EFIPPS) a pragmatic three-arm cluster randomised trial:designing the intervention (ClinicalTrials.gov registration NCT01602705)
Peer reviewedPublisher PD
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