754 research outputs found
An audit of provincial gastroenterology services in the Western Cape
Background: While disorders such as gastro-oesophageal reflux disease, gastrointestinal (GI) cancers and inflammatory bowel disease are prevalent among all racial groups in the Western Cape, there is little knowledge of local GI service provision. The state of equipment, facilities and staffing is largely unrecorded and to date unknown. The aim of this study was to audit the availability of GI facilities in the provincial sector, which provides care for the majority of people in the Western Cape. Method: All hospitals in the Western Cape providing endoscopy were evaluated by means of a hands-on audit, to identify available organisational infrastructure. Data including staffing, details and utilisation of existing equipment, maintenance and disinfection techniques and delays in service provision were collected. Results: Over a period of 12 months, 17 Western Cape hospitals were visited : 3 tertiary, 5 regional and 9 district-level institutions. There are currently 89 GI endoscopes in state service, with an average age of 6.1 years (range 1 - 23 years). While most institutions utilise video endoscopy, in many instances equipment is near the end of its economic life. A total of 26 434 endoscopic procedures were performed over a 12-month period. Overall at least 60% of all adult endoscopy was undertaken at tertiary institutions. The mean delay from consultation until gastroscopy or colonoscopy was 9.25 weeks (range 0.5 - 28 weeks) and 8 weeks (range 1 - 20 weeks), respectively. Only 1 tertiary and 1 regional hospital employed fully trained, registered nurses, and the majority of institutions did not conform to internationally accepted standards for the maintenance and disinfection of endoscopic equipment. Conclusion: While endoscopy equipment is widely distributed throughout the province, it is evident from this study that services in the Western Cape fall short of international standards, with delays in endoscopic provision, lack of adequate equipment, inadequate scope maintenance and disinfection and a shortage of trained staff. As such, much of the population reliant on state facilities has poor access to GI health care. These deficiencies need to be addressed
Transition to subcritical turbulence in a tokamak plasma
Tokamak turbulence, driven by the ion-temperature gradient and occurring in
the presence of flow shear, is investigated by means of local, ion-scale,
electrostatic gyrokinetic simulations (with both kinetic ions and electrons) of
the conditions in the outer core of the Mega-Ampere Spherical Tokamak (MAST). A
parameter scan in the local values of the ion-temperature gradient and flow
shear is performed. It is demonstrated that the experimentally observed state
is near the stability threshold and that this stability threshold is nonlinear:
sheared turbulence is subcritical, i.e. the system is formally stable to small
perturbations, but, given a large enough initial perturbation, it transitions
to a turbulent state. A scenario for such a transition is proposed and
supported by numerical results: close to threshold, the nonlinear saturated
state and the associated anomalous heat transport are dominated by long-lived
coherent structures, which drift across the domain, have finite amplitudes, but
are not volume filling; as the system is taken away from the threshold into the
more unstable regime, the number of these structures increases until they
overlap and a more conventional chaotic state emerges. Whereas this appears to
represent a new scenario for transition to turbulence in tokamak plasmas, it is
reminiscent of the behaviour of other subcritically turbulent systems, e.g.
pipe flows and Keplerian magnetorotational accretion flows.Comment: 16 pages, 5 figures, accepted to Journal of Plasma Physic
Ion-scale turbulence in MAST: anomalous transport, subcritical transitions, and comparison to BES measurements
We investigate the effect of varying the ion temperature gradient (ITG) and
toroidal equilibrium scale sheared flow on ion-scale turbulence in the outer
core of MAST by means of local gyrokinetic simulations. We show that nonlinear
simulations reproduce the experimental ion heat flux and that the
experimentally measured values of the ITG and the flow shear lie close to the
turbulence threshold. We demonstrate that the system is subcritical in the
presence of flow shear, i.e., the system is formally stable to small
perturbations, but transitions to a turbulent state given a large enough
initial perturbation. We propose that the transition to subcritical turbulence
occurs via an intermediate state dominated by low number of coherent long-lived
structures, close to threshold, which increase in number as the system is taken
away from the threshold into the more strongly turbulent regime, until they
fill the domain and a more conventional turbulence emerges. We show that the
properties of turbulence are effectively functions of the distance to
threshold, as quantified by the ion heat flux. We make quantitative comparisons
of correlation lengths, times, and amplitudes between our simulations and
experimental measurements using the MAST BES diagnostic. We find reasonable
agreement of the correlation properties, most notably of the correlation time,
for which significant discrepancies were found in previous numerical studies of
MAST turbulence.Comment: 67 pages, 37 figures. Submitted to PPC
Idea-caution before exploitation:the use of cybersecurity domain knowledge to educate software engineers against software vulnerabilities
The transfer of cybersecurity domain knowledge from security experts (âEthical Hackersâ) to software engineers is discussed in terms of desirability and feasibility. Possible mechanisms for the transfer are critically examined. Software engineering methodologies do not make use of security domain knowledge in its form of vulnerability databases (e.g. CWE, CVE, Exploit DB), which are therefore not appropriate for this purpose. An approach based upon the improved use of pattern languages that encompasses security domain knowledge is proposed
Neurodevelopmental evaluation and referral practices in children with congenital heart disease in central South Africa
Introduction: Children with congenital heart disease (CHD) are at higher risk for developmental delays than the general population. The American Heart Association (AHA) published a guideline to address these concerns in 2012. This study determined the neurodevelopmental evaluation and referral practices of practitioners in central South Africa.Method: An online survey was administered to practitioners (n=45) including paediatric cardiologists (n=4), cardiothoracic surgeons (n=4) and general paediatricians (n=37). Information on practitioner characteristics, awareness of the 2012 AHA guideline; and neurodevelopmental evaluation and referral practices was collected.Results: Twenty-one practitioners responded, including paediatric cardiologists (n=4), cardiothoracic surgeons (n=2) and paediatricians (n=15). Data for 20 practitioners was included. Despite most practitioners (n=18) indicating guidelines for the management of development were important, the majority (n=16; 80%) were unaware of the guideline. Most practitioners (n=18; 90%) failed to risk stratify children to identify those to be evaluated. Children with developmental delays were referred for formal developmental evaluation (n=11; 55%) and to intervention therapies (n= 15; 75%).Conclusion: Most practitioners are unaware of the 2012 AHA guideline. Awareness of the developmental risks associated with CHD and implementation of the guideline could promote early identification of developmental delays with referral to intervention therapies
Ethnobotanical plant uses in the KwaNibela Peninsula, St Lucia, South Africa
Abstract Ethnobotanical field studies were conducted for the first time in the KwaNibela Peninsula of southern Maputaland, KwaZulu-Natal, to document indigenous knowledge about useful plants. The vernacular names and uses of 82 plant species were recorded and compared to published Zulu and Swazi knowledge. Medicines for skin disorders, toothache, wounds, worms, chest and throat ailments, infertility and purgatives are still commonly used. Superstition and divination play a major role in the traditional knowledge system of the people of KwaNibela with 24 plants used for this purpose. Three KwaNibela medicinal plants (Erythroxylum delagoense, Putterlickia verrucosa, and Teclea natalensis) appear to be new records, not previously reported in the general scientific literature. The list also includes 61 novel uses of plants and another 15 new variations on known (published) uses. Ten previously unpublished vernacular names are presented, together with an additional 19 new variants of known names. These new additions to the scientific literature confirm that indigenous knowledge in KwaZulu-Natal is not yet completely recorded
The Role of Entrepreneur-Venture Fit in Online Home-based Entrepreneurship: A Systematic Literature Review
Home-based businesses and their founders represent an important, but under-researched facet of entrepreneurship. Far from being small, hobby-businesses with little economic impact, home-based business make significant contribution to national economies in terms of both turnover and employment. Online home-based businesses have been recognised as an important and distinct sector of the home-based business domain, offering unique opportunity for innovation and business diversity. The paper presents a systematic literature review of extant research on online home-based entrepreneurs and their businesses. The findings of the review are structured and discussed using the theoretical lens of entrepreneur-venture fit. Use of this lens allows the study to bring coherence to previously fragmented extant studies, providing a basis for future research in this domain. The study also develops a novel model of entrepreneur-venture fit in the specific case of online home-based businesses. This allows us to suggest five positive interactions between entrepreneurial and venture characteristics. It also allows us to suggest a number of previously unidentified negative interactions, which may result in entrepreneurs becoming âlocked-inâ and suffering multiple sources of stress
Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058-5234
We present the analysis of a total of 177h of high-quality optical
time-series photometry of the helium atmosphere pulsating white dwarf (DBV) EC
20058-5234. The bulk of the observations (135h) were obtained during a WET
campaign (XCOV15) in July 1997 that featured coordinated observing from 4
southern observatory sites over an 8-day period. The remaining data (42h) were
obtained in June 2004 at Mt John Observatory in NZ over a one-week observing
period. This work significantly extends the discovery observations of this
low-amplitude (few percent) pulsator by increasing the number of detected
frequencies from 8 to 18, and employs a simulation procedure to confirm the
reality of these frequencies to a high level of significance (1 in 1000). The
nature of the observed pulsation spectrum precludes identification of unique
pulsation mode properties using any clearly discernable trends. However, we
have used a global modelling procedure employing genetic algorithm techniques
to identify the n, l values of 8 pulsation modes, and thereby obtain
asteroseismic measurements of several model parameters, including the stellar
mass (0.55 M_sun) and T_eff (~28200 K). These values are consistent with those
derived from published spectral fitting: T_eff ~ 28400 K and log g ~ 7.86. We
also present persuasive evidence from apparent rotational mode splitting for
two of the modes that indicates this compact object is a relatively rapid
rotator with a period of 2h. In direct analogy with the corresponding
properties of the hydrogen (DAV) atmosphere pulsators, the stable low-amplitude
pulsation behaviour of EC 20058 is entirely consistent with its inferred
effective temperature, which indicates it is close to the blue edge of the DBV
instability strip. (abridged)Comment: 19 pages, 8 figures, 5 tables, MNRAS accepte
Monoclonal antibodies to receptors for insulin and somatomedin-C.
Three monoclonal antibodies, designated alpha IR-1, alpha IR-2, and alpha IR-3, were prepared by fusing FO myeloma cells with spleen cells from a mouse immunized with a partially purified preparation of insulin receptors from human placenta. These antibodies were characterized by their ability to immunoprecipitate solubilized receptors labeled with 125I-insulin or 125I-somatomedin-C in the presence or absence of various concentrations of unlabeled insulin or somatomedin-C. alpha IR-1 preferentially immunoprecipitates insulin receptors and also less effectively immunoprecipitates somatomedin-C receptors, while alpha IR-2 and alph IR-3 preferentially immunoprecipitate somatomedin-C receptors, but may also weakly immunoprecipitate insulin receptors. These three monoclonal antibodies, as well as A410, a rabbit polyclonal antibody, were used to immunoprecipitate insulin and somatomedin-C receptors from solubilized human lymphoid (IM-9) cells and human placenta membranes that had been 125I-labeled with lactoperoxidase. Analysis of the immunoprecipitates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicates that both receptors are composed of alpha and beta subunits. The beta subunit of the insulin receptor (immunoprecipitated by alpha IR-1 and A410) has a slightly more rapid mobility than the corresponding subunit of the somatomedin-C receptor (immunoprecipitated by alpha IR-2 and alpha IR-3). Interestingly, the alpha subunit of the placenta somatomedin-C receptor has a slightly faster mobility than its counterpart from IM-9 cells. Immunoprecipitation of receptor that had been reduced and denatured to generate isolated subunits indicates that alpha IR-2 and alpha IR-3 interact with the alpha subunit of the somatomedin-C receptor while A410 interacts with both subunits of the insulin receptor. alpha IR-1 failed to react with reduced and denatured receptors
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