Regionalisation Of Hospital Infrastructure In The Eastern Transvaal Area

A Dissertation Submitted to the Faculty of Medicine University of the Witwatersrand, Johannesburg for the Degree of Master of Medicine (Community Health)The extremely complex fragmentation of health services in the greater South Africa has lead to confusion, duplication and uncoordinated planning. This study assesses the hospital component of the health services in one discrete geographical area where service responsibilities are particularly complex. Each of the hospitals identified within the study area was visited and, after a short conducted tour, detailed information was obtained on a standard questionnaire during interviews with senior hospital personnel. Final detail was obtained by inspection of various functional components in each hospital. Proposals regarding the process of regionalising the hospital services in a future post-apartheid era (when political boundaries, particularly homeland boundaries, have disappeared and the health services can be rationalised under a unified health authority) are made. The major finding is that, while some expansion is needed, the existing facilities can be reorganised into a functional complex at minimal cost and limited disruption of services.AC 201

Small Satellite Launch to LEO:A Review of Current and Future Launch Systems

As minaturisation of ever improving enabling technologies increase the capabilities of small satellites, the issue of commercially affordable access to Earth orbit becomes more significant. Whilst the current practice of multiple manifesting is dominant, the emergence of new small launch vehicles may instigate a transition to the dedicated launch of these small satellites. A brief review of the current range of launch vehicles is presented and available small satellite launch market projections briefly examined. The small launch vehicles currently in development are also outlined and their potential to drive the future small satellite launch market discussed

The benefits of very low earth orbit for earth observation missions

Very low Earth orbits (VLEO), typically classified as orbits below approximately 450 km in altitude, have the potential to provide significant benefits to spacecraft over those that operate in higher altitude orbits. This paper provides a comprehensive review and analysis of these benefits to spacecraft operations in VLEO, with para-metric investigation of those which apply specifically to Earth observation missions. The most significant benefit for optical imaging systems is that a reduction in orbital altitude improves spatial resolution for a similar payload specification. Alternatively mass and volume savings can be made whilst maintaining a given performance. Similarly, for radar and lidar systems, the signal-to-noise ratio can be improved. Additional benefits include improved geospatial position accuracy, improvements in communications link-budgets, and greater launch vehicle insertion capability. The collision risk with orbital debris and radiation environment can be shown to be improved in lower altitude orbits, whilst compliance with IADC guidelines for spacecraft post-mission lifetime and deorbit is also assisted. Finally, VLEO offers opportunities to exploit novel atmosphere-breathing electric propulsion systems and aerodynamic attitude and orbit control methods. However, key challenges associated with our understanding of the lower thermosphere, aerodynamic drag, the requirement to provide a meaningful orbital lifetime whilst minimising spacecraft mass and complexity, and atomic oxygen erosion still require further research. Given the scope for significant commercial, societal, and environmental impact which can be realised with higher performing Earth observation platforms, renewed research efforts to address the challenges associated with VLEO operations are requiredThis project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 737183Peer ReviewedPostprint (author's final draft

R-loop formation during S phase is restricted by PrimPol-mediated repriming

During DNA replication conflicts with ongoing transcription are frequent and require careful management to avoid genetic instability. R-loops, three stranded nucleic acid structures comprising a DNA:RNA hybrid and displaced single stranded DNA, are important drivers of damage arising from such conflicts. How R-loops stall replication and the mechanisms that restrain their formation during S phase are incompletely understood. Here we show in vivo how R-loop formation drives a short purine-rich repeat, (GAA)10, to become a replication impediment that engages the repriming activity of the primase-polymerase PrimPol. Further, the absence of PrimPol leads to significantly increased R-loop formation around this repeat during S phase. We extend this observation by showing that PrimPol suppresses R-loop formation in genes harbouring secondary structure-forming sequences, exemplified by G quadruplex and H-DNA motifs, across the genome in both avian and human cells. Thus, R- loops promote the creation of replication blocks at susceptible structure-forming sequences, while PrimPol-dependent repriming limits the extent of unscheduled R-loop formation at these sequences, mitigating their impact on replication

Technology Challenges of SURROUND: A Constellation of Small Satellites Around the Sun for Tracking Solar Radio Bursts

The SURROUND mission proposes the operational monitoring and forecasting of space weather events using a constellation of five small satellites in orbit around the Sun. This unique mission concept would enable the localisation and tracking of solar events with unprecedented accuracy. The small payload combined with high launch requirements makes this an ideal candidate mission for a distributed constellation of small spacecraft and provides an opportunity for technical development in the areas of deep space communication, propulsion, and survivability. The baseline configuration for SURROUND proposes the deployment of spacecraft to Earth-Sun Lagrange points L1, L4, and L5, and two additional spacecraft in Earth leading (\u3c 1AU) and trailing (\u3e 1AU) orbits. However, the development and realisation of such a constellation in deep space presents a number of challenges, particularly when the use of small spacecraft is considered. This paper presents the conceptual design for the proposed SURROUND constellation, principally focusing on the key technical challenges of deploying the spacecraft into their desired locations around the Sun and subsequently communicating the collected data back to Earth. In addition to the key propulsion system and communications architecture trades, additional technological challenges of the mission are also considered, including attitude control, radiation hardening, and electromagnetic compatibility

Editorial

The credo - reaffirming our professionalismThe quest for ethics in medicineThe public service labour relations shamblesSensitisation, pre-emptive and total analgesiaThe resurrection ofprimary percutaneous transluminal coronary angioplasty for the treatment of acute myocardial infarctionPrimary health care depends on the district health syste