The 16-day variation in tidal amplitudes at Grahamstown (33.3° S, 26.5° E)

International audienceMeteor wind data at Grahamstown (33.3° S, 26.5° E) have been used to study the short-term (planetary scale) variations of the diurnal and semidiurnal tidal amplitudes at ~ 90 km altitude. Wavelet multi-resolution and spectral techniques reveal that planetary periodicities of ~ 10 and ~ 16 days dominate the wave spectrum in the ~ 2?20-day period range. The quasi-16-day oscillation is thought to be related to similar oscillations in the lower atmosphere. Also, there seems to be a link between the winter/equinox 16-day oscillation in the mean flow and that in the semidiurnal tidal amplitudes. It is thought that this is probably due to either the coupling between the normal mode-mean flow interactions and the gravity wave-tidal interactions, or to direct nonlinear interactions between planetary waves and the tide. On the other hand, a comparison of the mean flow and the diurnal tide does not show evidence of correlation. Possible reasons for this disparity are discussed briefly

The 16-day variation in the mean flow at Grahamstown (33.3° S, 26.5° E)

International audienceData from the Grahamstown (33.3° S, 26.5° E) meteor radar have been used to study the short-term variations of the mean flow at ~ 90 km altitude. The results show considerable variation characterised by a superposition of fluctuations on different planetary time scales. Wavelet multi-resolution and spectral techniques reveal that the quasi-16-day oscillation dominates the wave spectrum in the ~ 2?20-day period range. This quasi-16-day oscillation, which is thought to be related to a similar oscillation in the lower atmosphere, is found to be dominant in winter and the equinoxes. However, it is sometimes significant in summer, which could be due to cross-equatorial ducting and the selective transmissivity of gravity waves

Extracting gravity wave parameters during the September 2002 Southern Hemisphere major sudden stratospheric warming using a SANAE imaging riometer

Using absorption data measured by imaging riometer for ionospheric studies (IRIS) located at the South Africa National Antarctic Expedition (SANAE), Antarctica (72° S, 3° W), we extracted the parameters of gravity waves (GW) of periods between 40 and 50 min during late winter/spring of the year 2002, a period of the unprecedented major sudden stratospheric warming (SSW) in the Southern Hemisphere middle atmosphere. During this period, an unprecedented substantial increase of temperature by about 25–30 K throughout the stratosphere was observed. During the period of the occurrence of the major stratospheric warming, there was a reduction of both the GW horizontal phase speeds and the horizontal wavelengths at 90 km. The GW phase speeds and horizontal wavelengths were observed to reach minimum values of about 7 m s⁻¹ and 19 km, respectively, while during the quiet period the average value of the phase speed and horizontal wavelength was approximately 23 m s⁻¹ and 62 km, respectively. The observed event is discussed in terms of momentum flux and also a potential interaction of gravity waves, planetary waves and mean circulation

Basic Science (Chemistry)

Exam paper for second semester National Diploma (Emergency Medical Care ; Podiatry

Modelling to inform next-generation medical interventions for malaria prevention and treatment

Global progress against malaria has stagnated and novel medical interventions to prevent malaria are needed to fill gaps in existing tools and improve protection against infection and disease. Candidate selection for next-generation interventions should be supported by the best available evidence. Target product profiles and preferred product characteristics play a key role in setting selection criteria requirements and early endorsement by health authorities. While clinical evidence and expert opinion often inform product development decisions, integrating modelling evidence early and iteratively into this process provides an opportunity to link product characteristics with expected public health outcomes. Population models of malaria transmission can provide a better understanding of which, and at what magnitude, key intervention characteristics drive public health impact, and provide quantitative evidence to support selection of use-cases, transmission settings, and deployment strategies. We describe how modelling evidence can guide and accelerate development of new malaria vaccines, monoclonal antibodies, and chemoprevention

The views of patients with spinal cord injuries on their rehabilitation experience

Background and Purpose: Spinal rehabilitation programs seek to enhance the residual functional abilities of people who have an acquired disabling impairment because of SCI. Very little has been published on how patients experience rehabilitation, and what the implication of their experience is on rehabilitation outcomes. The aim of this pilot study was to explore the views of patients with SCI regarding their experience of rehabilitation while in hospital. Materials and Methods: A qualitative exploratory study using semi-structured interviews was employed. Twelve patients constituted the sample of convenience. Qualitative techniques were used to analyze the data. Results: The study revealed a variety of psycho-emotional issues related to the patients’ experience of rehabilitation. Positive issues included being treated humanly, being told the truth about their condition early on, family involvement in rehabilitation and being allowed to contribute to decision making regarding their rehabilitation. Negative issues were mainly their lack of insight into their health condition. Conclusion: The study highlighted important psycho-emotional issues related to the patients’ experience of rehabilitation. Rehabilitation personnel must consider these issues when working with patients with spinal cord injury, to ensure effective rehabilitation outcomes