A systematic approach to error isolation in computerized wastewater simulation models

Activated sludge models are used extensively in the study of wastewater treatment processes. While various commercial implementations of these models are available, there are many people who need to code models themselves using the simulation packages available to them, Quality assurance of such models is difficult. While benchmarking problems have been developed and are available, the comparison of simulation data with that of commercial models leads only to the detection, not the isolation of errors. To identify the errors in the code is time-consuming. In this paper, we address the problem by developing a systematic and largely automated approach to the isolation of coding errors. There are three steps: firstly, possible errors are classified according to their place in the model structure and a feature matrix is established for each class of errors. Secondly, an observer is designed to generate residuals, such that each class of errors imposes a subspace, spanned by its feature matrix, on the residuals. Finally. localising the residuals in a subspace isolates coding errors. The algorithm proved capable of rapidly and reliably isolating a variety of single and simultaneous errors in a case study using the ASM 1 activated sludge model. In this paper a newly coded model was verified against a known implementation. The method is also applicable to simultaneous verification of any two independent implementations, hence is useful in commercial model development.

A systematic study of the microwave and thermal cure kinetics of the DGEBA/DDS and DGEBA/DDM epoxy-amine resin systems

The microwave and thermal cure processes for the epoxy-amine systems (epoxy resin diglycidyl ether of bisphenol A, DGEBA) with 4,4'-diaminodiphenyl sulphone (DDS) and 4,4'-diaminodiphenyl methane (DDM) have been investigated for 1:1 stoichiometries by using fiber-optic FT-NIR spectroscopy. The DGEBA used was in the form of Ciba-Geigy GY260 resin. The DDM system was studied at a single cure temperature of 373 K and a single stoichiometry of 20.94 wt% and the DDS system was studied at a stoichiometry of 24.9 wt% and a range of temperatures between 393 and 443 K. The best values of the kinetic rate parameters for the consumption of amines have been determined by a least squares curve fit to a model for epoxy/amine cure. The activation energies for the polymerization of the DGEBA/DDS system were determined for both cure processes and found to be 66 and 69 kJ mol(-1) for the microwave and thermal cure processes, respectively. No evidence was found for any specific effect of the microwave radiation on the rate parameters, and the systems were both found to be characterized by a negative substitution effect. Copyright (C) 2002 John Wiley Sons, Ltd.

How well do general practitioners deliver palliative care? A systematic review

General practitioners (GPs) deliver the majority of palliative care to patients in the last year of life. This article seeks to examine the nature of GP care, perceptions of the GPs themselves and others of that care, the adequacy of palliative care training, issues relating to accessibility of GPs to palliative care patients, and strategies that may be of use in encouraging more effective delivery of palliative care by GPs. Medline and PubMed databases from 1966 to 2000 were searched, and 135 references identified. Sixty-six of these described studies relevant to GP palliative care. GPs value this part of their work. Most of the time, patients appreciate the contribution the GP makes to palliative care particularly if the GP is accessible, takes time to listen, allows patient and carer to ventilate their feelings, and is seen to be making efforts made regarding symptom relief. However, reports from bereaved relatives suggest that palliative care is performed less well in the community than in other settings. GPs express discomfort about their competence to perform palliative care adequately. They tend to miss symptoms which are not treatable by them, or which are less common. However, with appropriate specialist support and facilities, GPs have been shown to deliver sound and effective care. GP comfort working with specialist teams increases with exposure to this form of patient management, as does the understanding of the potential other team members have in contributing to the care of the patient. Formal arrangements engaging GPs to work with specialist teams have been shown to improve functional outcomes, patient satisfaction, improve effective use of resources and improve effective physician behaviour in other areas of medicine. Efforts by specialist services to develop formal involvement of GPs in the care of individual patients, may be an effective method of improving GP palliative care skills and appreciation of the roles specialist services can play.

Does primary medical practitioner involvement with a specialist team improve patient outcomes? A systematic review.

Patients with chronic or complex medical or psychiatric conditions are treated by many practitioners, including general practitioners (GPs). Formal liaison between primary and specialist is often assumed to offer benefits to patients The aim of this study was to assess the efficacy of formal liaison of GPs with specialist service providers on patient health outcomes, by conducting a systematic review of the published literature in MEDLINE, EMBASE, PsychINFO, CINAHL and Cochrane Library databases using the following search terms family physicians': synonyms of 'patient care planning', 'patient discharge' and 'patient care team'; and synonyms of 'randomised controlled trials'. Seven studies were identified, involving 963 subjects and 899 controls. most health outcomes were unchanged, although some physical and functional health outcomes were improved by formal liaison between GPs and specialist services, particularly among chronic mental illness patients. Some health outcomes worsened during the intervention. Patient retention rates within treatment programmes improved with GP involvement, as did patient satisfaction. Doctor (GP and specialist) behaviour changed, with reports of more rational use of resources and diagnostic tests, improved clinical skills, more frequent use of appropriate treatment strategies, and more frequent clinical behaviours designed to detect disease complications Cost effectiveness could not be determined. In conclusion, formal liaison between GPs and specialist services leaves most physical health outcomes unchanged, but improves functional outcomes in chronically mentally ill patients. It may confer modest long-term health benefits through improvements in patient concordance with treatment programmes and more effective clinical practice.

Benefits, harms and costs of screening mammography in women 70 years and over: a systematic review

Objective: To assess the (i) benefits, (ii) harms and (iii) costs of continuing mammographic screening for women 70 years and over. Data sources and synthesis: (i) We conducted a MEDLINE search (1966 - July 2000) for decision-analytic models estimating life-expectancy gains from screening in older women. The five studies meeting the inclusion criteria were critically appraised using standard criteria. We estimated relative benefit from each model's estimate of effectiveness of screening in older women relative to that in women aged 50-69 years using the same model. (ii) With data from BreastScreen Queensland, we constructed balance sheets of the consequences of screening for women in 10-year age groups (40-49 to 80-89 years), and (iii) we used a validated model to estimate the marginal cost-effectiveness of extending screening to women 70 years and over. Results: For women aged 70-79 years, the relative benefit was estimated as 40%-72%, and 18%-62% with adjustment for the impact of screening on quality of life. For women over 80 years the relative benefit was about a third, and with quality-of-life adjustment only 14%, that in women aged 50-69 years. (ii) Of 10 000 Australian women participating in ongoing screening, about 400 are recalled for further testing, and, depending on age, about 70-112 undergo biopsy and about 19-80 cancers are detected. (iii) Cost-effectiveness estimates for extending the upper age limit for mammographic screening from 69 to 79 years range from $8119 to $27 751 per quality-adjusted life-year saved, which compares favourably with extending screening to women aged 40-49 years (estimated at between $24 000 and $65 000 per life-year saved). Conclusions: Women 70 years and over, in consultation with their healthcare providers, may want to decide for themselves whether to continue mammographic screening. Decision-support materials are needed for women in this age group.

Introducing OTseeker (Occupational Therapy Systematic Evaluation of Evidence): A new evidence database for occupational therapists

OTseeker (Occupational Therapy Systematic Evaluation of Evidence) is a new resource for occupational therapists that has been designed with the principle aim of increasing access to research to support clinical decisions. It contains abstracts of systematic reviews and quality ratings of randomized controlled trials (RCTs) relevant to occupational therapy. It is available, free of charge, at www.otseeker.com. This paper describes the OTseeker database and provides an example of how it may support occupational therapy practice.

Systematic characterization of mutations in yeast acetohydroxyacid synthase: Interpretation of herbicide-resistance data

Acetohydroxyacid synthase (AHAS, EC 4.1.3.18) catalyses the first step in branched-chain amino acid biosynthesis and is the target for sulfonylurea and imidazolinone herbicides, which act as potent and specific inhibitors. Mutants of the enzyme have been identified that are resistant to particular herbicides. However, the selectivity of these mutants towards various sulfonylureas and imidazolinones has not been determined systematically. Now that the structure of the yeast enzyme is known, both in the absence and presence of a bound herbicide, a detailed understanding of the molecular interactions between the enzyme and its inhibitors becomes possible. Here we construct 10 active mutants of yeast AHAS, purify the enzymes and determine their sensitivity to six sulfonylureas and three imidazolinones. An additional three active mutants were constructed with a view to increasing imidazolinone sensitivity. These three variants were purified and tested for their sensitivity to the imidazolinones only. Substantial differences are observed in the sensitivity of the 13 mutants to the various inhibitors and these differences are interpreted in terms of the structure of the herbicide-binding site on the enzyme.

Systematic review of the role of pre-oxygenation for tracheal suctioning in ventilated newborn infants

Pre-oxygenation for endotracheal suctioning for mechanically ventilated infants is routine practice in many neonatal intensive care units. In the present systematic review the evidence to support its use is discussed and the authors conclude that no confident recommendations can be made from the results of this review.

Additions to the systematic of the bethylid fauna (Hymenoptera, Chrysidoidea) from Chile

Bethylopsis carinatus sp.n., and Epyris chilensis sp.n., from Chile are described and illustrated. Taxonomic data on Chilepyris herbsti Evans, Lytopsenella herbsti (Kieffer), Lytopsenella testaceicornis (Kieffer) and Pseudisobrachium erythrocephalum Evans are included. Male of Lytopsenella herbsti is recorded for the first time to genus and species.

Additional notes on systematic of Neotropical Dissomphalus Ashmead (Hymenoptera, Bethylidae)

Diagnosis and genitalia description and illustration of Dissomphalus bicavatusEvans, 1979;D. bispinulatusEvans, 1969;D. brasiliensisKieffer, 1910;Z). caviclypeus Evans, 1969; D. cornutus Evans 1964; D. dumosus, Evans, 1966; D. fungosus Evans, 1979; D. gilvipes Evans, 1979; D. incomptus Evans, 1964; D. infissus Evans, 1969; D. mendicus Evans, 1969; D. microstictus Evans, 1969; D. mirabilis Evans, 1966; D. nanellus Evans, 1969; D. napo Evans, 1979; D. plaumanni Evans, 1964; D. punctatus (Kieffer, 1910); D. puteolus Evans, 1969; D. rufipalpis Kieffer, 1910; D. xanthopus Ashmead, 1893 are provided. Female of D. mirabilis is first described. Five synonymies are proposed: D. connubialis Evans, 1966 of D. brasiliensis, D. montanus Kieffer, 1910 of D. punctatus, D. obliquus Evans, 1979 of D. rufipalpis, D. teren Evans, 1969 of D. cornutus and D. hastatus Evans, 1979 of D. bispinulatus. D. microtuberculatus sp.n. from Northern Argentina is described and illustrated.