Paediatric burns in a rural South African district hospital

Objectives. To describe the epidemiology, clinical features, management and outcome of children with burns admitted to a rural district hospital. Design. A retrospective analysis of the case notes of consecutive cases of paediatric burns. Setting. Hlabisa Hospital, KwaZulu-Natal - a 450-bed rural district hospital serving approximately 200 000 people. Subjects. All cases of paediatric burns (age < 12 years) admitted to Hlabisa Hospital in 1994. Main outcome measures. Number of admissions, month of admission, age, sex, time to presentation, site of burn, complications, number of surgical procedures, adherence to management protocol and outcome. Results. One hundred and forty-nine children presented to the outpatient department in 1994 and 88 (59%) were admitted, The median age of those admitted was 36 months with 66 (75%) aged less than 5 years; 42 (48%) were boys, Thirty-nine children (44%) were admitted during the four winter months of May to August, The average interval from the tirne of the burn to presentation at hospital was 42 hours (range 1 - 120). Sixty-eight burns (77%) were due to hot fluid or food burning the legs, trunk or arms, There was a high level of morbidity, Nineteen (22%) children developed wound infections, 5 (6%) developed contractures and 20 (23%) required a total of 32 surgical procedures, There was 1 death, Burns were responsible for more paediatric patient days spent in hospital than any condition other than malnutrition, and a longer length of stay was associated with delay in presentation, Children presenting within 24 hours of the burn had a mean length of stay of 12.8 days, compared with 25.2 days (P = 0.03) for children presenting 24 hours or more after the burn. Twenty of the 22 children who stayed for longer than 3 weeks or who required transfer were judged to have been managed inadequately in at least one respect compared with 3 of 48 who were discharged within 2 weeks or not transferred (P < 0.001). Conclusion. This study shows that paediatric burns are an important cause of morbidity and contribute significantly to inpatient stay in this rural setting. The lengthy delay from time of burn to presentation at hospital is of serious concern and our results show that this delay is associated with increased hospital stay. As most burns were due to spillage of hot fluids or food there seems to be significant potential for preventive interventions. Community-based studies would help to estimate the true incidence of burns and would contribute to an understanding of the reasons for delay in presentation. The information gathered is being used to inform the development of a burns prevention programme.4 page(s

Multicycle dynamics of fault systems and static and dynamic triggering of earthquakes

Dynamic simulations of rupture propagation and multiple earthquake cycles for varying fault geometries are presented. We investigate the role of both dynamic and static stress changes on earthquake triggering. Dynamic stress triggering of earthquakes is caused by the passage of seismic waves, whereas static stress triggering is due to net slippage on a fault resulting from an earthquake. Static stress changes represented by a Coulomb failure function and its relationship to seismicity rate change is a relatively well-known mechanism, whereas the physical origin of dynamic triggering remains one of the least understood aspects of earthquake nucleation. We investigate these mechanisms by analysing seismicity patterns with varying fault separation, geometry and with and without dynamic triggering present

Modeling dimethylsulphide production in the upper ocean

Dimethylsulphide (DMS) is produced by upper ocean ecosystems and emitted to the atmosphere, where it may have an important role in climate regulation. Several attempts to quantify the role of DMS in climate change have been undertaken in modeling studies. We examine a model of biogenic DMS production and describe its endogenous dynamics and sensitivities. We extend the model to develop a one-dimensional version that more accurately resolves the important processes of the mixed layer in determining the ecosystem dynamics. Comparisons of the results of the one-dimensional model with an empirical relationship that describes the global distribution of DMS, and also with vertical profiles of DMS in the upper ocean measured at the Bermuda Atlantic Time Series, suggest that the model represents the interaction between the biological and physical processes well on local and global scales. Our analysis of the model confirms its veracity and provides insights into the important processes determining DMS concentration in the oceans

Costs of tree seed and seedling supply systems. The cost of integrating genetic diversity into forest landscape restoration.

Genetic and physiological quality are crucial for the short and long-term success of restoration projects. While physiological quality has a considerable influence on both the germination rate of seedlings and the immediate vitality of the seedling after planting, genetic quality enables a planted population to adapt to a changing environment, and positively correlates with an increased resilience to pests and diseases. Moreover, genetic quality is considered to be an important prerequisite that allows seedlings to establish under prevailing conditions at the planting site and thus to avoid or decrease mortality due to maladaptation. Although there is broad consensus about the advantages of integrating genetic quality into Forest Landscape Restoration (FLR), markets often fail to offer seed of high genetic quality, resulting in genetic quality hardly being considered in current restoration projects. Besides the possible lack of appropriate guidelines or a general lack of awareness about the importance of genetic diversity, a collection strategy that prefers quantity over (genetic) quality might also be a reason for this. It may be economically feasible to collect as many seeds as possible from a few nearby trees, but the disadvantages of this strategy far outweigh the advantages. The resulting lack of genetic quality potentially leads to a (total) failure of a restoration initiatives, which ultimately entails a loss of investment and hence comes with significantly higher costs compared to the costs that were saved during collection. In order to better understand the interrelationships between costs, benefits, properties of the supply chain (e.g., vegetation cover at the planting site), and quality considerations (physical, physiological, plant health, and genetic) we developed a cost model that integrates relevant cost drivers of the tree seed and seedling supply chain into a single cost structure. By presenting a holistic view of relevant cause-effect relationships, we aim to help decision makers and practitioners to take better informed decisions and to create appropriate incentives, which are reflected, for example, in genetic quality-dependent prices for seeds. The model is based on a framework that represents important components of and interrelations within currently applied seed sourcing strategies, as well as associated costs and mechanisms to which these costs are subjected

Electron Exchange Coupling for Single Donor Solid-State Qubits

Inter-valley interference between degenerate conduction band minima has been shown to lead to oscillations in the exchange energy between neighbouring phosphorus donor electron states in silicon \cite{Koiller02,Koiller02A}. These same effects lead to an extreme sensitivity of the exchange energy on the relative orientation of the donor atoms, an issue of crucial importance in the construction silicon-based spin quantum computers. In this article we calculate the donor electron exchange coupling as a function of donor position incorporating the full Bloch structure of the Kohn-Luttinger electron wavefunctions. It is found that due to the rapidly oscillating nature of the terms they produce, the periodic part of the Bloch functions can be safely ignored in the Heitler-London integrals as was done by Koiller et. al. [Phys. Rev. Lett. 88,027903(2002),Phys. Rev. B. 66,115201(2002)], significantly reducing the complexity of calculations. We address issues of fabrication and calculate the expected exchange coupling between neighbouring donors that have been implanted into the silicon substrate using an 15keV ion beam in the so-called 'top down' fabrication scheme for a Kane solid-state quantum computer. In addition we calculate the exchange coupling as a function of the voltage bias on control gates used to manipulate the electron wavefunctions and implement quantum logic operations in the Kane proposal, and find that these gate biases can be used to both increase and decrease the magnitude of the exchange coupling between neighbouring donor electrons. The zero-bias results reconfirm those previously obtained by Koiller.Comment: 10 Pages, 8 Figures. To appear in Physical Review

Aerosol climate feedback due to decadal increases in Southern Hemisphere wind speeds

Observations indicate that the westerly jet in the Southern Hemisphere troposphere is accelerating. Using a global aerosol model we estimate that the increase in wind speed of 0.45 + /- 0.2 m s(-1) decade(-1) at 50-65 degrees S since the early 1980s caused a higher sea spray flux, resulting in an increase of cloud condensation nucleus concentrations of more than 85% in some regions, and of 22% on average between 50 and 65 degrees S. These fractional increases are similar in magnitude to the decreases over many northern hemisphere land areas due to changes in air pollution over the same period. The change in cloud drop concentrations causes an increase in cloud reflectivity and a summertime radiative forcing between at 50 and 65 degrees S comparable in magnitude but acting against that from greenhouse gas forcing over the same time period, and thus represents a substantial negative climate feedback. However, recovery of Antarctic ozone depletion in the next two decades will likely cause a fall in wind speeds, a decrease in cloud drop concentration and a correspondingly weaker cloud feedback

Perineal Assessment and Repair Longitudinal Study (PEARLS): a matched-pair cluster randomized trial.

Perineal trauma during childbirth affects millions of women worldwide every year. The aim of the Perineal Assessment and Repair Longitudinal Study (PEARLS) was to improve maternal clinical outcomes following childbirth through an enhanced cascaded multiprofessional training program to support implementation of evidence-based perineal management

Variability of atmospheric dimethylsulphide over the southern Indian Ocean due to changes in ultraviolet radiation

Dimethylsulphide (DMS) is a climatically important component of global biogeochemical cycles, through its role in the sulphur cycle. Changes in ultraviolet radiation (UV) exhibit both positive and negative forcings on the dynamics of production and turnover of DMS and its precursor dimethylsulphoniopropionate (DMSP). In this study we investigate the net forcing of UV on atmospheric DMS. The work is based on a 10-year record of observed DMS at Amsterdam Island in the southern Indian Ocean, and satellite-based retrievals of surface UV and photosynthetically active radiation (PAR). The results show an inverse relationship between UV radiation and atmospheric DMS associated with extreme changes (defined as the greatest 5%) in daily UV, independent of changes in wind speed, sea surface temperature, and PAR

Assessing shrub distribution and impact in tallgrass prairie using aerial and ground-based mapping. American Society for Photogrammetry and Remote Sensing Technical Papers

ABSTRACT Woody plant invasion of native tallgrass prairie can result in degradation of the herbaceous community and eventual replacement by woody communities. Methods are needed to assess shrub distribution and potential impacts in prairie ecosystems. This study examined distribution and effects of the shrub smooth sumac (Rhus glabra L.) in the Rockefeller Native Prairie, a small prairie remnant in northeastern Kansas. We assessed distribution using ground-based measurements and aerial imagery, established a baseline for monitoring, and quantified both sumac and herbaceous biomass as a function of sumac stem density. Photo-and ground-based maps, each showing four categories of sumac density, indicate that sumac grows in approximately 35% of the prairie. We tested the hypothesis that increasing sumac abundance is associated with decreasing herbaceous biomass. We found that herbaceous biomass is negatively correlated with sumac abundance, expressed as either density or biomass. Our sampling design allowed us to show that this inverse relationship holds for mapped sumac density classes, thus allowing us to infer impacts within mapped units throughout the prairie