396 research outputs found
An approach to the patient with a post-nasal drip and rhinosinusitis
Post-nasal drip (PND) can be a bothersome symptom and one of the main reasons for patients visiting a general practitioner (GP), pulmonologist or ear, nose and throat (ENT) surgeon. It can be either a symptom, sometimes not appreciated by the examining practitioner, or an important clinical sign suggesting rhinosinusitis. This article aims to explain the aetiological factors and initial work-up of the patient with a PND and rhinosinusitis and suggest a treatment paradigm for practitioners
Allergic fungal sinusitis secondary to Acremonium species causing unilateral visual loss
A wide range of fungi have been associated with Allergic Fungal Sinusitis (AFS) or Eosinophilic fungal rhinosinusitis ( EFRS) as it is known in some institutions. To our knowledge, this is the first reported case of aggressive, invasive AFS due to Acremonium species occurring in an immunocompetent patient and leading to unilateral visual loss. Literature on AFS is reviewed.Key words: Eosinophilic fungal rhinosinusitis, Allergic fungal sinusitis, Acremonium species, visual loss
Tracheal stenosis: Preventable morbidity on the increase in our intensive care units
Following a marked increase in patients with tracheal stenosis at Groote Schuur Hospital, we re-examined this problem to identify new trends. Practitioners should be aware of this problem and that tracheal stenosis is an avoidable complication of endotracheal (ET) intubation. It is invariably difficult to treat, a heavy treatment burden and has an associated significant morbidity and reduction in quality of life. A 10-year retrospective review of patients that presented with or were referred to our service with tracheal stenosis showed no new patterns to be responsible for the increase incidence of stenosis. Therefore we conducted a survey of endotracheal tube (ETT) cuff pressures and cuff monitoring practises in local intensive care units (ICUs). This revealed that cuff pressures were dangerously elevated in 30% of all intubated patients surveyed in the ICUs. We are concerned that poor cuff pressure monitoring practises may be responsible for the increase in tracheal stenosis
Endogenous orienting modulates the Simon effect: critical factors in experimental design
Responses are faster when the side of stimulus and response correspond than when they do not correspond, even if stimulus location is irrelevant to the task at hand: the correspondence, spatial compatibility effect, or Simon effect. Generally, it is assumed that an automatically generated spatial code is responsible for this effect, but the precise mechanism underlying the formation of this code is still under dispute. Two major alternatives have been proposed: the referential-coding account, which can be subdivided into a static version and an attention-centered version, and the attention-shift account. These accounts hold clear-cut predictions for attentional cuing experiments. The former would assume a Simon effect irrespective of attentional cuing in its static version, whereas the attention-centered version of the referential-coding account and the attention-shift account would predict a decreased Simon effect on validly as opposed to invalidly cued trials. However, results from previous studies are equivocal to the effects of attentional cuing on the Simon effect. We argue here that attentional cueing reliably modulates the Simon effect if some crucial experimental conditions, mostly relevant for optimizing attentional allocation, are met. Furthermore, we propose that the Simon effect may be better understood within the perspective of supra-modal spatial attention, thereby providing an explanation for observed discrepancies in the literature
Fractal Holography: a geometric re-interpretation of cosmological large scale structure
The fractal dimension of large-scale galaxy clustering has been demonstrated
to be roughly from a wide range of redshift surveys. If correct,
this statistic is of interest for two main reasons: fractal scaling is an
implicit representation of information content, and also the value itself is a
geometric signature of area. It is proposed that the fractal distribution of
galaxies may thus be interpreted as a signature of holography (``fractal
holography''), providing more support for current theories of holographic
cosmologies. Implications for entropy bounds are addressed. In particular,
because of spatial scale invariance in the matter distribution, it is shown
that violations of the spherical entropy bound can be removed. This holographic
condition instead becomes a rigid constraint on the nature of the matter
density and distribution in the Universe. Inclusion of a dark matter
distribution is also discussed, based on theoretical considerations of possible
universal CDM density profiles.Comment: 13 pp, LaTeX. Revised version; to appear in JCA
Statistical mechanics of image restoration and error-correcting codes
We develop a statistical-mechanical formulation for image restoration and
error-correcting codes. These problems are shown to be equivalent to the Ising
spin glass with ferromagnetic bias under random external fields. We prove that
the quality of restoration/decoding is maximized at a specific set of parameter
values determined by the source and channel properties. For image restoration
in mean-field system a line of optimal performance is shown to exist in the
parameter space. These results are illustrated by solving exactly the
infinite-range model. The solutions enable us to determine how precisely one
should estimate unknown parameters. Monte Carlo simulations are carried out to
see how far the conclusions from the infinite-range model are applicable to the
more realistic two-dimensional case in image restoration.Comment: 20 pages, 9 figures, ReVTe
Recommended centrifuge method: specific grain size separation in the <63 µm fraction of marine sediments
The isolation of specific grain size classes of lithogenic samples and biogenic carbonate from the <63 µm fraction (i.e. clay and silt) of marine sediment is often a prerequisite to further pre-treatments and/or analytical measurements for palaeoceanographic studies. Established techniques employed have included sieving, settling and micro-filtration (and/or a combination of these). However, these methods often use significant amounts of bulk sediment (often up to ∼3 g) and/or require considerable amounts of time during sediment processing (ranging from 48 hours to 3 weeks) to isolate a size specific class for further analyses. Here, we build on previous approaches to isolate three grain size classes (e.g. <2 µm, clay; 2-10 µm, fine silt; and 10-63 µm, coarse silt) from the <63 µm fraction of marine sediment with the aid of a centrifuge at varying revolutions per minute using Stokes’ Law. We show the utility of our approach using two common sediment types dominated by (i) lithogenic and (ii) biogenic carbonate (specifically coccoliths) components of marine sediment cores. Our method reduces the amount of sample material required to 1-2 g to provide an isolated clay fraction (or other targeted size fraction) and decreases the sample processing time (to ∼1 hour) to enable high throughput of analysis, when compared to previous techniques for palaeoceanographic proxy measurements.
• We recommend a more straightforward grain size isolation method for lithogenic sediment and biogenic carbonate sediment types
• Isolating commonly targeted grain size fractions for palaeoceanographic studies using a centrifug
Using honey to heal diabetic foot ulcers
Diabetic ulcers seem to be arrested in the inflammatory/proliferative stage of the healing process, allowing infection and inflammation to preclude healing. Antibiotic-resistant bacteria have become a major cause of infections, including diabetic foot infections. It is proposed here that the modern developments of an ancient and traditional treatment for wounds, dressing them with honey, provide the solution to the problem of getting diabetic ulcers to move on from the arrested state of healing. Honeys selected to have a high level of antibacterial activity have been shown to be very effective against antibiotic-resistant strains of bacteria in laboratory and clinical studies. The potent anti-inflammatory action of honey is also likely to play an important part in overcoming the impediment to healing that inflammation causes in diabetic ulcers, as is the antioxidant activity of honey. The action of honey in promotion of tissue regeneration through stimulation of angiogenesis and the growth of fibroblasts and epithelial cells, and its insulin-mimetic effect, would also be of benefit in stimulating the healing of diabetic ulcers. The availability of honey-impregnated dressings which conveniently hold honey in place on ulcers has provided a means of rapidly debriding ulcers and removing the bacterial burden so that good healing rates can be achieved with neuropathic ulcers. With ischemic ulcers, where healing cannot occur because of lack of tissue viability, these honey dressings keep the ulcers clean and prevent infection occurring
Yang-Mills instantons and dyons on homogeneous G_2-manifolds
We consider Lie G-valued Yang-Mills fields on the space R x G/H, where G/H is
a compact nearly K"ahler six-dimensional homogeneous space, and the manifold R
x G/H carries a G_2-structure. After imposing a general G-invariance condition,
Yang-Mills theory with torsion on R x G/H is reduced to Newtonian mechanics of
a particle moving in R^6, R^4 or R^2 under the influence of an inverted
double-well-type potential for the cases G/H = SU(3)/U(1)xU(1),
Sp(2)/Sp(1)xU(1) or G_2/SU(3), respectively. We analyze all critical points and
present analytical and numerical kink- and bounce-type solutions, which yield
G-invariant instanton configurations on those cosets. Periodic solutions on S^1
x G/H and dyons on iR x G/H are also given.Comment: 1+26 pages, 14 figures, 6 miniplot
The impact of an employee wellness programme in clothing/textile manufacturing companies: a randomised controlled trial
BACKGROUND: The prevalence of health risk behaviours is growing amongst South African employees. Health risk behaviours have been identified as a major contributor to reduced health related quality of life (HRQoL) and the increased prevalence of non-communicable diseases. Worksite wellness programmes promise to promote behaviour changes amongst employees and to improve their HRQoL. The aim of this study was to evaluate the short-term effects of an employee wellness programme on HRQoL, health behaviour change, body mass index (BMI) and absenteeism amongst clothing and textile manufacturing employees. METHODS: The study used a randomised control trial design. The sample consisted of 80 subjects from three clothing manufacturing companies in Cape Town, South Africa. The experimental group was subjected to a wellness programme based on the principles of cognitive behaviour therapy (CBT) as well as weekly supervised exercise classes over six weeks. The control group received a once-off health promotion talk and various educational pamphlets, with no further intervention. Measurements were recorded at baseline and at six weeks post-intervention. Outcome measures included the EQ-5D, Stanford Exercise Behaviours Scale, body mass index and absenteeism.Data was analysed with the Statistica-8 software program. Non-parametric tests were used to evaluate the differences in the medians between the two groups and to determine the level of significance. The Sign test was used to determine the within group changes. The Mann-Whitney U test was used to determine the difference between the two groups. RESULTS: At six weeks post intervention the experimental group (39 subjects) demonstrated improvement in almost every parameter. In contrast, apart from an overall decrease in time off work and a reduction in BMI for all study participants, there was no significant change noted in the behaviour of the control group (41 subjects). Seventy percent of the experimental group had improved HRQoL EQ-5D VAS scores post intervention, indicating improved perceived HRQoL. In comparison, only 58% of the control group had improved HRQoL EQ-5D VAS scores post intervention. There was no significant difference between the two groups at baseline or at six weeks post intervention. CONCLUSION: An employee wellness programme based on the principles of CBT combined with weekly aerobic exercise class was beneficial in improving the perceived HRQoL and changing health-related behaviours of clothing manufacturing employees. However, it cannot be concluded that the EWP was more effective than the once off health promotion talk as no significant changes were noted between the two groups at 6-weeks post intervention.This trial has been registered with ClinicalTrials.gov (trial registration number NCT01625039)
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