Glaucoma in general practice

Glaucoma is a silent condition very rarely presenting with headaches and only leading to decreased vision in the very advanced stages. Disc cupping and intraocular pressure measurement are important features in making the diagnosis. Acute angle closure is very rare and needs urgent referral. Most patients will be well controlled with medical therapy alone.For full text, click here:SA Fam Pract 2006;48(7):46-4

Higher symmetries of the Schrödinger operator in Newton–Cartan geometry

This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.geomphys.2016.06.003We establish several relationships between the non-relativistic conformal symmetries of Newton–Cartan geometry and the Schrödinger equation. In particular we discuss the algebra sch(d) of vector fields conformally-preserving a flat Newton–Cartan spacetime, and we prove that its curved generalisation generates the symmetry group of the covariant Schrödinger equation coupled to a Newtonian potential and generalised Coriolis force. We provide intrinsic Newton–Cartan definitions of Killing tensors and conformal Schrödinger–Killing tensors, and we discuss their respective links to conserved quantities and to the higher symmetries of the Schrödinger equation. Finally we consider the role of conformal symmetries in Newtonian twistor theory, where the infinite-dimensional algebra of holomorphic vector fields on twistor space corresponds to the symmetry algebra cnc(3) on the Newton–Cartan spacetime.I am supported by an STFC studentship

Exploring bone mineral density changes in total knee arthroplasty revisions and the impact of conal implants

Introduction The link between low bone mineral density (BMD) leading to greater fracture risk is well established in the literature; what is not fully understood is the impact of total knee revisions (rTKR) and cone implantation on BMD. This is important due to the increasing fracture risk associated with reductions in BMD. This feasibility study investigated a new type of Stryker cone for rTKR patients, and its impact on BMD utilising different imaging technologies and providing recommendations to be implemented for a full follow up trial. Method A systematic review was conducted to investigate total knee replacement (TKR) and rTKR on BMD results to establish known reported BMD changes after surgery, and to highlight the knee regions investigated. A bovine study was then conducted in order to test the different setup imaging technologies and possible analysis of the cones. Additionally, a novel piece of 3D SHAPER hip software was utilised to investigate bone changes in the hip across three groups (TKR, rTKR, and controls) which could then be compared to the main BMD changes or used as an alternative to the other imaging options. The main study involved recruiting 37 participants all undergoing rTKR to either a cone or non cone group, with all participants undergoing a series of scans via: CT scans (only at six months), DXA and x ray at intervals of pre op, six weeks, three, six and 12 months. Additionally, all participants completed questionnaires on mental health, lower extremity functionality, and quality of life. In addition to BMD investigation, hip and knee alignment was also explored at pre and post op intervals, as well as pixel density changes, both utilising long leg x ray imaging. Results Systematic review results reported 2,431 papers, of which 27 studies were included, across all the studies BMD losses appeared greatest at 12 months. The bovine study helped develop the imaging and analysis required for the main study. The 3D SHAPER ability to be applied to hip DXA imaging showed promise; which was reflected in the control, rTKR and TKR data. The development of different imaging technologies have potential in moving forward into a full trial. Recommendations would include: utilising DXA imaging as the main modality, given its gold standard for BMD changes and its consistency when using a standardised positioning protocol and ROI placement. Long leg x- 3 ray imaging to be used to investigate alignment and pixel density changes, as this imaging is convenient as part of routine follow-up care, although the inclusion of a step wedge within all long leg images would be required to allow pixel density standardisation for investigating in-growth. Finally, the CT imaging could not determine ingrowth in this feasibility study, and therefore should not be utilised in the full study. For the main feasibility study results, 35 participants attended pre--op, 26 attended six weeks and three months, at six months 25 attended, and 22 at 12 months. Results show rTKR is associated with lower BMD in the tibial and femoral stems, and in the medial tibial condyle, and associated with increases beyond the tibial and femoral stems, in both groups. The main difference is in lateral tibial condyle where there are associated increases in BMD in the cone group, and losses reported in the non--cone group. The questionnaire results show a favourable impact for rTKR, with reductions in depression, anxiety, and increases in functionality post--surgery, with the cone group reporting greater changes, although not statistically significant between groups. Alignment analysis shows little difference between

The design of a modelling framework to simulate the local food system of a rural community in Zimbabwe

In sub-Saharan Africa, forecasts of regional or national scale malnutrition are prepared using a variety of ‘Early Warning Systems’, based upon supply-side data such as crop forecasts and satellite images of vegetation growth. Three agencies are developing more localised targeting systems using historical indicators to prepare ‘vulnerability assessments’ and so predict malnutrition at sub-national scales. This work argues that an alternative approach of short-term simulations of local food systems, may offer benefits.The design of a modelling framework to carry out such a simulation, for a rural community of Zimbabwe, is presented together with the associated data requirements. The thesis reviews the current literature concerning food security, particularly the monitoring of food shortages, the targeting of emergency food aid and the economic and nutritional perspectives of the causes of malnutrition. The extent of spatial and temporal variability amongst households is analysed from primary survey data. The design implications of this variability and of the hierarchical structure o f the rural socio-economy and grain trading are discussed. Two versions of the modelling framework are reported, the first using systems dynamic modelling and the second using expert systems simulation techniques.The first framework uses the UNICEF diagram of the ‘malnutrition-infection complex’ to develop the central component of the simulation. The second framework combines a ‘rulebase’ of household and com m unity behaviour with rainfall and health statistics to effect changes upon a database of households, data for which are extrapolated from the primary survey and secondary data obtained. The effectiveness of the framework and the direction of future work thereon are discussed

Non-Relativistic Twistor Theory and Newton–Cartan Geometry

We develop a non-relativistic twistor theory, in which Newton--Cartan structures of Newtonian gravity correspond to complex three-manifolds with a four-parameter family of rational curves with normal bundle ${\mathcal O}\oplus{\mathcal O}(2)$. We show that the Newton--Cartan space-times are unstable under the general Kodaira deformation of the twistor complex structure. The Newton--Cartan connections can nevertheless be reconstructed from Merkulov's generalisation of the Kodaira map augmented by a choice of a holomorphic line bundle over the twistor space trivial on twistor lines. The Coriolis force may be incorporated by holomorphic vector bundles, which in general are non--trivial on twistor lines. The resulting geometries agree with non--relativistic limits of anti-self-dual gravitational instantons.We are grateful to Christian Duval, George Sparling and Paul Tod for helpful discussions. This work started when MD was visiting the Institute for Fundamental Sciences (IMP) in Tehran in April 2010. MD is grateful to IMP for the extended hospitality when volcanic eruption in Iceland halted air travel in Europe. The work of JG has been supported by an STFC studentship.This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00220-015-2557-

Transforming the Entrepreneurial Landscape: Emergent Innovative Behaviors in Internet Firms

Implications for opportunity identification, alliance formation, and strategic orientation of Internet entrepreneurs are presented as preliminary steps toward a new netpreneurship model of business formation