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Approaches the shakedown optimal design of reinforced concrete (RC) structures, subjected to variable and repeated external quasi‐static actions which may generate the…
Approaches the shakedown optimal design of reinforced concrete (RC) structures, subjected to variable and repeated external quasi‐static actions which may generate the well‐known shakedown or adaptation phenomenon, when constraints are imposed on deflection and/or deformation parameters, in order to simulate the limited flexural ductility of the material, in the presence of combined axial stress and bending. Within this context, the classical shakedown optimal design problem is revisited, using a weak upper bound theorem on the effective plastic deformations. For this problem a new computational algorithm, termed evolution strategy, is herein presented. This algorithm, derived from analogy with the biological evolution, is based on random operators which allow one to treat the areas of steel reinforcements at each RC cross‐section of the structure as design variables of discrete type, and to use refined non‐linear approximations of the effective bending moment – axial force M‐N interaction diagrams of each RC cross‐section. The results obtained from case studies available in the literature show the advantages of the method and its effectiveness.
This paper is devoted to the optimal design of laminated composite structures. The goal of the study is to assess the quality and the performance of an algorithm based on…
This paper is devoted to the optimal design of laminated composite structures. The goal of the study is to assess the quality and the performance of an algorithm based on the directional derivative method. Particular attention is paid to the one‐dimensional search, a critical step of the process, performed by cubic splines approximation. The optimization problem is formulated as weight minimization, under constraints on the mechanical behavior of the structure. The assumed design variables are the ply thicknesses, treated as continuous design variables, constrained by technological requirements. The structural analysis is performed making use of quadrilateral four‐node composite elements, based on the first order shear deformation theory. The algorithm is applied to the optimization of a rectangular laminated plate. The results obtained are compared with those obtained by other similar studies and show the effectiveness and accuracy of the proposed approach.
Despite the increasing evidence about the inappropriate use of medications by older people, there is very little published evidence about the control and monitoring of…
Despite the increasing evidence about the inappropriate use of medications by older people, there is very little published evidence about the control and monitoring of neuroleptic drugs used in nursing homes. As others have indicated, this is all the more worrying when set in the context of the paucity of research on nursing home care and the trend to replace registered nurses with untrained care assistants. In the United States, legislation in the form of the Nursing Home Reform Act (OBRA 1987) was introduced, in part, to regulate the prescribing and administration of neuroleptic (antipsychotic) drugs. No such legislation exists in Canada or the United Kingdom. In the case of the latter jurisdiction, the recent Royal Commission on Long‐Term Care for older people (The Stationery Office, 1999) has recommended a national care commission to monitor care, and set assessment and quality benchmarks. In Canada this debate has not even begun, and the purpose of this paper is not to ignite controversy, but to raise questions about the use of these drugs with nursing home residents. Voluntary guidelines and education of physicians, nurses and care attendants would be infinitely better than legislation. In the meantime, we need research to address the following questions: For what reasons should these drugs be given to older people? Are these drugs being used appropriately? Is the risk of side‐effects too great with these drugs? Are the numbers and type of staff employed in nursing homes adequate/qualified to detect and report side‐effects? How well do these drugs manage the behaviours they are given to control? Are they being used as chemical restraints or to make the older person compliant? Are the so‐called ‘atypical’ neuroleptic drugs any better? What we offer in this article is background information that might encourage others to not only review their practice but also to address these questions.
Medication errors are an important patient safety issue. Electronic medication reconciliation is a system designed to correct medication discrepancies at transitions in…
Medication errors are an important patient safety issue. Electronic medication reconciliation is a system designed to correct medication discrepancies at transitions in healthcare. The purpose of this paper is to measure types and prevalence of intravenous antibiotic errors at hospital discharge before and after the addition of an electronic discharge medication reconciliation tool (EDMRT).
A retrospective study was conducted at a tertiary hospital where house officers order discharge medications. In total, 100 pre-EDMRT and 100 post-EDMRT subjects were randomly recruited from the study center’s clinical Outpatient Parenteral Antimicrobial Therapy (OPAT) program. Using infectious disease consultant recommendations as gold standard, each antibiotic listed in these consultant notes was compared to the hospital discharge orders to ascertain the primary outcome: presence of an intravenous antibiotic error in the discharge orders. The primary covariate of interest was pre- vs post-EDMRT group. After generating the crude prevalence of antibiotic errors, logistic regression accounted for potential confounding: discharge day (weekend vs weekday), average years of practice by prescribing physician, inpatient service (medicine vs surgery) and number of discharge mediations per patient.
Prevalence of medication errors decreased from 30 percent (30/100) among pre-EDMRT subjects to 15 percent (15/100) errors among post-EDMRT subjects. Dosage errors were the most common type of medication error. The adjusted odds ratio of discharge with intravenous antibiotic error in the post-EDMRT era was 0.39 (0.18, 0.87) compared to the pre-EDMRT era. In the adjusted model, the total number of discharge medications was associated with increased OR of discharge error.
To the authors’ knowledge, no other study has examined the impact of reconciliation on types and prevalence of medication errors at hospital discharge. The focus on intravenous antibiotics as a class of high-stakes medications with serious risks to patient safety during error events highlights the clinical importance of the findings. Electronic medication reconciliation may be an important tool in efforts to improve patient safety.