Toward the Ab-initio Description of Medium Mass Nuclei

As ab-initio calculations of atomic nuclei enter the A=40-100 mass range, a great challenge is how to approach the vast majority of open-shell (degenerate) isotopes. We add realistic three-nucleon interactions to the state of the art many-body Green's function theory of closed-shells, and find that physics of neutron driplines is reproduced with very good quality. Further, we introduce the Gorkov formalism to extend ab-initio theory to semi-magic, fully open-shell, isotopes. Proof-of-principle calculations for Ca-44 and Ni-74 confirm that this approach is indeed feasible. Combining these two advances (open-shells and three-nucleon interactions) requires longer, technical, work but it is otherwise within reach.Comment: Contribution to Summary Report of EURISOL Topical and Town Meetings, 15-19 October 2012; missing affiliations added and corrected errors in Tab

FISHRENT; Bio-economic simulation and optimisation model

Key findings: The FISHRENT model is a major step forward in bio-economic model-ling, combining features that have not been fully integrated in earlier models: 1- Incorporation of any number of species (or stock) and/or fleets 2- Integration of simulation and optimisation over a period of 25 years 3- Integration of effort and TAC-driven management policies 4- Three independent relations for stock growth, production and investments. The feedbacks within the model allow for a dynamic simulation. The main application of the model is scenario analysis of policy options. Complementary findings: The model formulates a complete set of mathematical relations, but it also con-tains a number of important assumptions, which remain to be tested empirically. Therefore the model presents a challenging agenda for empirical research, which should lead to further qualitative and quantitative improvements of the in-dividual mathematical equations and parameter values. Method: This model was developed during the EU-funded project 'Remuneration of spawning stock biomass'. Its aim was to generate consistent sets of scenarios for an assessment of potential resource rents in different EU fisheries. The model comprises six modules, each focussing on a different aspect of the functioning of the fisheries system: biology (stocks), economy (costs, earnings and profits), policy (TACs, effort and access fees), behaviour (investments), prices (fish and fuel) and an interface linking the modules together. Input, calculation and output are clearly separated. The model produces a standard set of graphics, which provide a quick insight into the results of any model run. All output of the model runs can be exported to database software for further analysis. The model has been built in Excel, which makes it accessible for most us-ers. It has been used in new applications and even translated to other software. The model is continually further developed

Unsuspected glucose abnormalities in patients with coronary artery disease

Objectives: To compare the ability of fasting glucose, glycosylated haemoglobin (HbA1c), the American Diabetic Association (ADA) score and measures of the metabolic syndrome (waist circumference, high-density lipoprotein (HDL), and triglycerides) in predicting an initial diagnosis of diabetes mellitus or abnormal glucose tolerance based on the World Health Organization (WHO) criteria.Design: A cross-sectional, diagnostic study was undertaken of 120 patients admitted to the cardiology wards of Pretoria Academic Hospital for elective coronary angiographic studies. Main outcome measures: All subjects underwent a modified glucose tolerance test whereby fasting and 2-hour post glucose (75 g) plasma glucose levels were measured. Using the revised WHO criteria, the overall incidence of diabetes was found to be 11.7% (95% confidence interval (CI): 6.5 - 19) and the overall incidence of abnormal glucose tolerance was 46% (CI: 37 - 55). Results: In univariate analysis for the diagnosis of diabetes, HbA1c (p < 0.05) yielded the largest area (0.76) under the receiver operating characteristic (ROC) curve, with a sensitivity of 21%, specificity of 99%, positive predictive value (PPV) of 75% and negative predictive value (NPV) of 91%. For the prediction of abnormal glucose tolerance, applying multivariate analysis using a logistic regression model, the combination of age, ethnic group, serum HDL, serum triglycerides and HbA1c yielded an area under the ROC curve of 0.79, sensitivity of 66%, specificity of 80%, PPV of 76% and a NPV of 71%. Conclusion: Most subjects with diabetes mellitus (9 of 14) would not have been detected if a 2-hour oral glucose tolerance test had not been done. Addition of either HbA1c or lipid parameters to the model of age and ethnic group were similar in predicting abnormal glucose tolerance. Journal of Endocrinology, Metabolism and Diabetes of South Africa Vol. 11(1) 2006: 24-2

The diagnostic value of lymph node biopsy to detect Castleman’s disease

HIV is not indicated in the aetiology of Castleman’s disease. However, it impacts on the prevalence and natural history of this disease and significantly on the disease progression. Castleman’s disease is a uni- or multicentric disease of the lymph node with or without polyclonal proliferation of B-cells. It is a morphologically distinct form of lymph node hyperplasia and is characterised by significant architectural changes in all lymphatic compartments. Histopathologically, the disease is classified into two major subtypes: the hyaline-vascular type and the plasma-cell type. A mixed type is also identified, as there are frequent transitions between the types. The diagnosis of Castleman’s disease needs to be made histologically. Treatment modalities include surgery, which is curative for unicentric disease, and systemic therapy, which is needed for multicentric disease. This case highlights the diagnostic value of lymph node excision biopsy in HIV-infected patients

Providing clinicians with information on laboratory test costs leads to reduction in hospital expenditure

Objectives. We aimed to ascertain the efficacy of an intervention in which laboratory test costs were provided to clinicians as a pocketsized brochure, in reducing laboratory test costs over a 4-month eriod. Methods. This was a non-randomised intervention study in the Internal Medicine wards at Steve Biko Academic Hospital, Pretoria, in which the intervention was laboratory test costs provided to clinicians as a pocket-sized brochure. The intervention period was the winter months of May - August 2008 and the pre-intervention period was the same months of the preceding year. In the two 4-month periods (2007 and 2008), the number of days in hospital and the laboratory tests ordered were computed for each patient admitted. For the intervention and control groups, pre- and postintervention cost and days in hospital were estimated. Results. The mean cost per patient admitted in the intervention group decreased from R2 864.09 to R2 097.47 &ndash; a 27% reduction. The mean cost per day in the intervention group as a whole also decreased, from R442.90 to R284.14 &ndash; a 36% reduction. Conclusion. Displaying the charges for diagnostic tests on the laboratory request form may significantly reduce both the number and cost of tests ordered, and by doing so bring about considerable in-hospital cost savings

Barriers to obstetric care among maternal near-misses

Background. There are several factors in the healthcare system that may influence a woman’s ability to access appropriate obstetric care.Objective. To determine the delays/barriers in providing obstetric care to women who classified as a maternal near-miss.Methods. This was a descriptive observational study at Steve Biko Academic Hospital, a tertiary referral hospital in Pretoria, South Africa. One hundred maternal near-misses were prospectively identified using the World Health Organization criteria. The ‘three-delays model’ was used to identify the phases of delay in the health system and recorded by the doctor caring for the patient.Results. One or more factors causing a delay in accessing care were identified in 83% of near-miss cases. Phase I and III delays were the most important causes of barriers. Lack of knowledge of the problem (40%) and inadequate antenatal care (37%) were important first-phase delays. Delay in patient admission, referral and treatment (37%) and substandard care (36%) were problems encountered within the health system. The above causes were also the most important factors causing delays for the leading causes of maternal near-misses – obstetric haemorrhage, hypertension/pre-eclampsia, and medical and surgical conditions.Conclusions. Maternal morbidity and mortality rates may be reduced by educating the community about symptoms and complications related to pregnancy. Training healthcare workers to identify and manage obstetric emergencies is also important. The frequency of antenatal visits should be revised, with additional visits in the third trimester allowing more opportunities for blood pressure to be checked and for identifying hypertension

In medium T-matrix for nuclear matter with three-body forces - binding energy and single particle properties

We present spectral calculations of nuclear matter properties including three-body forces. Within the in-medium T-matrix approach, implemented with the CD-Bonn and Nijmegen potentials plus the three-nucleon Urbana interaction, we compute the energy per particle in symmetric and neutron matter. The three-body forces are included via an effective density dependent two-body force in the in-medium T-matrix equations. After fine tuning the parameters of the three-body force to reproduce the phenomenological saturation point in symmetric nuclear matter, we calculate the incompressibility and the energy per particle in neutron matter. We find a soft equation of state in symmetric nuclear matter but a relatively large value of the symmetry energy. We study the the influence of the three-body forces on the single-particle properties. For symmetric matter the spectral function is broadened at all momenta and all densities, while an opposite effect is found for the case of neutrons only. Noticeable modification of the spectral functions are realized only for densities above the saturation density. The modifications of the self-energy and the effective mass are not very large and appear to be strongly suppressed above the Fermi momentum.Comment: 20 pages, 11 figure