A knowledge - based system to assist in the design of soil survey schemes

Soil survey information with quantified accuracy is relevant to decisions on land use and environmental problems. To obtain such information statistical strategies should be used for collecting and analysing data. A survey project based on a statistical sampling strategy requires a soil survey scheme specifying which sites are to be sampled, which data are to be recorded and how they are to be analysed statistically. The efficiency of such a scheme is determined by the accuracy of the survey results and the cost of operation. This accuracy and cost depend mainly on the method of determination and the sampling design in the scheme.This study aimed at formulating the basic design considerations of a knowledge-based system (KBS) to assist in the design of soil survey schemes. This system should incorporate pedological and statistical knowledge. The domain of the system has provisionally been limited to surveys for which a design-based approach, i.e. the use of classical sampling theory, is appropriate.Initially, the domain of the system has been structured in three layers: (i) an entity structure clarifying the position of the system in a soil survey project; (ii) a model describing the design process as a number of interrelated steps, and (iii) a conceptual framework defining the main concepts and their relations.Further analysis made it possible to specify the tasks in which the KBS should assist: definition of the survey request, selection of prior information, design of outlinear schemes, evaluation and optimization of outlinear schemes, generation of a report, and evaluation a posteriori .The system will primarily assist in the statistical decisions in the design process. Since there was no suitable classification of sampling designs available, a hierarchical framework of sampling designs has been constructed, in which sampling designs are grouped into types of designs, and types are grouped into classes of designs. Furthermore the main classes of sampling designs treated in the literature have been ordered in a taxonomy. Decision trees have been developed to guide the selection of an appropriate sampling approach (designbased versus model-based), and, in the case of a design-based approach, to guide the search for an appropriate class of sampling designs.To ensure that the available means for a project, such as budget, personnel, and equipment, are used adequately schemes should be evaluated and optimized beforehand. Models related to the features of sampling designs have been developed for predicting the accuracy and cost of survey schemes, the so-called prior evaluation. Furthermore the use of dynamic programming is proposed to search for the optimal sampling design within an outlinear scheme. The procedure enables objective comparison of schemes taking into account differences in spatial variability or sampling cost among sub-regions.Finally, basic design considerations are presented consisting of an initial requirements definition, a description of the intended use of the KBS, and a specification of the components for an actual KBS. Five components are distinguished: a database, a knowledge base, a model base, a problem-solving model, and a user interface. The system will assist in its own maintenance through continuous storage of knowledge from executed projects. This will facilitate the re-use of information. A KBS which is based on these basic design considerations will assist in controlling the quality of soil survey projects

Impact of diabetes mellitus on prediction of clinical outcome after coronary revascularization by ¹⁸F-FDG SPECT in patients with ischemic left ventricular dysfunction

Nuclear imaging using 18F-FDG is an established method for the noninvasive assessment of myocardial viability. Data on the value of 18F-FDG imaging in patients with diabetes mellitus are scarce. The aim of this study was to assess whether, in patients with diabetes mellitus and ischemic left ventricular (LV) dysfunction, 18/F-FDG imaging can predict improvement of LV function and heart failure symptoms after coronary revascularization. Methods: A total of 130 consecutive patients with ischemic LV dysfunction who were already scheduled for surgical revascularization were studied; 34 of the patients had diabetes mellitus. All patients underwent radionuclide ventriculography to assess left ventricular ejection fraction (LVEF), resting 2-dimensional echocardiography to identify dysfunctional myocardial tissue, and dual-isotope 18F-FDG/99m/Tc- tetrofosmin SPECT after oral administration of acipimox. Nine to 12 mo after coronary revascularization, radionuclide ventriculography and echocardiography were repeated. An improvement in LVEF by at least5% was considered significant. Results: 18F-FDG SPECT demonstrated that 610 (50%) of 1,212 dysfunctional segments were viable. Patients with and without diabetes mellitus had a comparable number of dysfunctional but viable segments per patient. Also, the number of patients with a substantial amount of dysfunctional but viable myocardium (≥ viable segments) was comparable between the groups with and without diabetes mellitus. The presence of substantial viability on 18F-FDG SPECT was predictive of improvement in LVEF and heart failure symptoms postoperatively (sensitivity and specificity of 82% and 89%, respectively, in patients with diabetes and 83% and 93%, respectively, in patients without diabetes; not statistically significant). Conclusion: 18F-FDG SPECT is practical for routine assessment of myocardial viability in patients with ischemic LV dysfunction with or without diabetes mellitus. Patients with substantial myocardial viability on 18F-FDG SPECT have a high probability of improvement of LV function and symptoms after coronary revascularization, irrespective of the absence or presence of diabetes mellitus.</p

Impact of diabetes mellitus on prediction of clinical outcome after coronary revascularization by ¹⁸F-FDG SPECT in patients with ischemic left ventricular dysfunction

Nuclear imaging using 18F-FDG is an established method for the noninvasive assessment of myocardial viability. Data on the value of 18F-FDG imaging in patients with diabetes mellitus are scarce. The aim of this study was to assess whether, in patients with diabetes mellitus and ischemic left ventricular (LV) dysfunction, 18/F-FDG imaging can predict improvement of LV function and heart failure symptoms after coronary revascularization. Methods: A total of 130 consecutive patients with ischemic LV dysfunction who were already scheduled for surgical revascularization were studied; 34 of the patients had diabetes mellitus. All patients underwent radionuclide ventriculography to assess left ventricular ejection fraction (LVEF), resting 2-dimensional echocardiography to identify dysfunctional myocardial tissue, and dual-isotope 18F-FDG/99m/Tc- tetrofosmin SPECT after oral administration of acipimox. Nine to 12 mo after coronary revascularization, radionuclide ventriculography and echocardiography were repeated. An improvement in LVEF by at least5% was considered significant. Results: 18F-FDG SPECT demonstrated that 610 (50%) of 1,212 dysfunctional segments were viable. Patients with and without diabetes mellitus had a comparable number of dysfunctional but viable segments per patient. Also, the number of patients with a substantial amount of dysfunctional but viable myocardium (≥ viable segments) was comparable between the groups with and without diabetes mellitus. The presence of substantial viability on 18F-FDG SPECT was predictive of improvement in LVEF and heart failure symptoms postoperatively (sensitivity and specificity of 82% and 89%, respectively, in patients with diabetes and 83% and 93%, respectively, in patients without diabetes; not statistically significant). Conclusion: 18F-FDG SPECT is practical for routine assessment of myocardial viability in patients with ischemic LV dysfunction with or without diabetes mellitus. Patients with substantial myocardial viability on 18F-FDG SPECT have a high probability of improvement of LV function and symptoms after coronary revascularization, irrespective of the absence or presence of diabetes mellitus.</p

Plasma natriuretic peptide levels reflect changes in heart failure symptoms, left ventricular size and function after surgical mitral valve repair

Background and aim: N-terminal pro-B-type natriuretic peptide (NT-proBNP) has diagnostic and prognostic value in patients with heart failure. The present prospective study was designed to assess whether changes in NT-proBNP levels after surgical mitral valve repair reflect changes in heart failure symptoms an

The benefits of statins in people without established cardiovascular disease but with cardiovascular risk factors: meta-analysis of randomised controlled trials

Objectives To investigate whether statins reduce all cause mortality and major coronary and cerebrovascular events in people without established cardiovascular disease but with cardiovascular risk factors, and whether these effects are similar in men and women, in young and older (>65 years) people, and in people with diabetes mellitus

Variations in clinical decision-making between cardiologists and cardiac surgeons; a case for management by multidisciplinary teams?

OBJECTIVE: To assess variations in decisions to revascularise patients with coronary heart disease between general cardiologists, interventional cardiologists and cardiac surgeons DESIGN: Six cases of coronary heart disease were presented at an open meeting in a standard format including clinical details which might influence the decision to revascularise. Clinicians (n = 53) were then asked to vote using an anonymous electronic system for one of 5 treatment options: medical, surgical (CABG), percutaneous coronary intervention (PCI) or initially medical proceeding to revascularisation if symptoms dictated. Each case was then discussed in an open forum following which clinicians were asked to revote. Differences in treatment preference were compared by chi squared test and agreement between groups and between voting rounds compared using Kappa. RESULTS: Surgeons were more likely to choose surgery as a form of treatment (p = 0.034) while interventional cardiologists were more likely to choose PCI (p = 0.056). There were no significant differences between non-interventional and interventional cardiologists (p = 0.13) in their choice of treatment. There was poor agreement between all clinicians in the first round of voting (Kappa 0.26) but this improved to a moderate level of agreement after open discussion for the second vote (Kappa 0.44). The level of agreement among surgeons (0.15) was less than that for cardiologists (0.34) in Round 1, but was similar in Round 2 (0.45 and 0.45 respectively) CONCLUSION: In this case series, there was poor agreement between cardiac clinical specialists in the choice of treatment offered to patients. Open discussion appeared to improve agreement. These results would support the need for decisions to revascularise to be made by a multidisciplinary panel

The impact of gender on long-term mortality in patients with multivessel disease after primary percutaneous coronary intervention

Background Gender and complete revascularisation are known to affect mortality. The objective of this study was to analyse a gender difference in mortality with respect to complete revascularisation for multivessel disease after primary percutaneous coronary intervention (PPCI) in STelevation myocardial infarction (STEMI) patients. Method In a prospective consecutive cohort of 1472 patients presenting with STEMI for PPCI, between January 2006 and January 2010, 832 patients with multivessel disease were analysed. The primary outcome was long-term mortality. Results Median follow-up was 3.3 ± 1.2 years. Complete revascularisation was performed less in females than in males (30 vs. 38%; p = 0.04). At PPCI, women (27%, n = 221) were ± 10 years older (p = 0.001), had more hypertension, renal failure and symptoms of heart failure (all p < 0.01). Cumulative long-term mortality with incomplete revasculari-sation was higher in females (F: 30 vs. M: 15%, p = 0.01). After adjustment for baseline characteristics, complete revascularisation (0.84; 95% CI 0.54–1.32) and gender (1.11; 95% CI 0.73–1.69) lost significance. Also the gender-bycomplete revascularisation interaction was not significant at long term. In women, age under 60 years independently predicted higher mortality (HR 10.09; 95% CI 3.08–33.08; p < 0.001). Conclusion In STEMI patients with multivessel disease at PPCI, women under the age of 60 years had higher mortality, but in women olde

Relationship of serum bilirubin concentration to kidney function and 24-hour urine protein in Korean adults

<p>Abstract</p> <p>Background</p> <p>The relationships among serum bilirubin concentration, kidney function and proteinuria have yet to be fully elucidated, nor have these relationships been investigated in Korean adults.</p> <p>Method</p> <p>We retrospectively reviewed the medical records of Korean adults who were evaluated at Kosin University Gospel Hospital (Busan, Republic of Korea) during a five-year period from January 2005 to December 2009. We evaluated the relationships among serum bilirubin concentration, estimated glomerular filtration rate (eGFR) and 24-hour urinary protein excretion in a sample of 1363 Korean adults aged 18 years or older.</p> <p>Results</p> <p>The values of eGFR <60 mL/min/1.73 m²and 24-hour urine albumin ≥150 mg/day were observed in 26.1% (n = 356) and 40.5% (n = 553) of subjects, respectively. Fasting glucose levels ≥126 mg/dL were observed in 44.9% (n = 612) of the total sample. After adjustment for potential confounding factors including demographic characteristics, comorbidities and other laboratory measures, total serum bilirubin was positively associated with eGFR and negatively associated with proteinuria both in the whole cohort and in a subgroup of diabetic individuals.</p> <p>Conclusions</p> <p>To our knowledge, this is the first hospital-based study specifically aimed at examining the relationships among serum total bilirubin concentration, 24-hour urine protein and kidney function in Korean adults. We demonstrated that serum total bilirubin concentration was negatively correlated with 24-hour urine protein and positively correlated with eGFR in Korean non-diabetic and diabetic adults.</p