8,930 research outputs found
The social cognition of medical knowledge, with special reference to childhood epilepsy
This paper arose out of an engagement in medical communication courses at a Gulf university. It deploys a theoretical framework derived from a (critical) sociocognitive approach to discourse analysis in order to investigate three aspects of medical discourse relating to childhood epilepsy: the cognitive processes that are entailed in relating different types of medical knowledge to their communicative context; the types of medical knowledge that are constituted in the three different text types analysed; and the relationship between these different types of medical knowledge and the discursive features of each text type. The paper argues that there is a cognitive dimension to the human experience of understanding and talking about one specialized from of medical knowledge. It recommends that texts be studied in medical communication courses not just in terms of their discrete formal features but also critically, in terms of the knowledge which they produce, transmit and reproduce
Comment on "Magnetic field effects on neutron diffraction in the antiferromagnetic phase of UPt3"
Moreno and Sauls [Phys. Rev. B 63, 024419 (2000)] have recently tried to
reanalyze earlier neutron scattering studies of the antiferromagnetic order in
UPt3 with a magnetic field applied in the basal plane. In their calculation of
the magnetic Bragg peak intensities, they perform an average over different
magnetic structures belonging to distinct symmetry representations. This is
incorrect. In addition, they have mistaken the magnetic field direction in one
of the experiments, hence invalidating their conclusions concerning the
experimental results.Comment: Revised 5 June 2001: Added group theory analysis and modified
discussion of S and K domain
Atomic quasi-Bragg diffraction in a magnetic field
We report on a new technique to split an atomic beam coherently with an
easily adjustable splitting angle. In our experiment metastable helium atoms in
the |{1s2s}^3S_1 M=1> state diffract from a polarization gradient light field
formed by counterpropagating \sigma^+ and \sigma^- polarized laser beams in the
presence of a homogeneous magnetic field. In the near-adiabatic regime, energy
conservation allows the resonant exchange between magnetic energy and kinetic
energy. As a consequence, symmetric diffraction of |M=0> or |M=-1> atoms in a
single order is achieved, where the order can be chosen freely by tuning the
magnetic field. We present experimental results up to 6th order diffraction (24
\hbar k momentum splitting, i.e., 2.21 m/s in transverse velocity) and present
a simple theoretical model that stresses the similarity with conventional Bragg
scattering. The resulting device constitutes a flexible, adjustable,
large-angle, three-way coherent atomic beam splitter with many potential
applications in atom optics and atom interferometry.Comment: 4 pages, 5 figure
Magnetism of Superconducting UPt3
The phase diagram of superconducting in pressure-temperature
plane, together with the neutron scattering data is studied within a two
component superconducting order parameter scenario. In order to give a
qualitative explanation to the experimental data a set of two linearly
independent antiferromagnetic moments which emerge appropriately at the
temperature \mbox{} and \mbox{} and
couple to superconductivity is proposed. Several constraints on the fourth
order coefficients in the Ginzburg-Landau free energy are obtained.Comment: 17 pages, figures available on request to
[email protected]
Palaeozoic insects of southern Africa: a review
Although a substantial number of Triassic insect fossils have been discovered in southern Africa, relatively few insect fossils are known from the Permian deposits of this region. Fossil insects from the Permian period elsewhere, including the extensive entomological fauna from Eastern Europe (including Russia), Brazil and Australia is well-documented. The Irati Formation in the Parana Basin of Brazil, the temporal and lithological correlate of the Permian Whitehill Formation of South Africa, has yielded fossil insects belonging to Homoptera, N europtera, Coleoptera and Mecoptera. Fossil insects from the Whitehill Formation are usually poorly preserved and only seven specimens are mentioned in the literature. An overview is given of the more recent discoveries of Permian fossil insects in South Africa. This includes the discovery of the oldest beetle in Africa, the oldest longhorned grasshopper in the Southern Hemisphere and a survey of the Permian insects from the Beaufort Group of Natal. Reasons for the paucity of Permian insects are briefly discussed.Palaeo-Anthropology Scientific Trust; French Embassy in South Africa; Co-operation and Cultural Servic
The effect of temporary prostatic stent on sexual function
This study was conducted to explore the effects of the bell-shaped Horizon prostatic stent on sexual function in the treatment of patients with LUTS/BPH
Free initial wave packets and the long-time behavior of the survival and nonescape probabilities
The behavior of both the survival S(t) and nonescape P(t) probabilities at
long times for the one-dimensional free particle system is shown to be closely
connected to that of the initial wave packet at small momentum. We prove that
both S(t) and P(t) asymptotically exhibit the same power-law decrease at long
times, when the initial wave packet in momentum representation behaves as O(1)
or O(k) at small momentum. On the other hand, if the integer m becomes greater
than 1, S(t) and P(t) decrease in different power-laws at long times.Comment: 4 pages, 3 figures, Title and organization changed, however the
results not changed, To appear in Phys. Rev.
Is locally advanced head and neck cancer ‘increasing’ in the Netherlands? The paradox of absolute numbers, standardized incidence rates and proportional share
Background: Several reports have indicated that locally advanced head and neck cancer (LAHNC) has increased in the past decade. However, incidence trends cannot be easily compared because slightly different definitions of LAHNC were used. Aim: To investigate if the incidence of locally advanced disease (LAD) in the oral cavity, oropharynx, hypopharynx and larynx is indeed increasing over time, considering the growing and ageing population in the Netherlands. Patients and methods: Data were obtained from the Netherlands Cancer Registry (NCR). Primary head and neck squamous cell carcinomas of the oral cavity, oropharynx, hypopharynx and larynx diagnosed between 1989 and 2017 were included. Yearly numbers and European standardized incidence rates (ESRs) were reported by extent of disease. The annual percentage change (APC) over time in ESRs was calculated to assess trends. Results: Absolute numbers and ESRs of LAD increased over time for oral cavity and most prominently for oropharynx carcinomas (before 1996, APC: 0.4, 95%CI: 0.1; 0.8 and APC: 5.7 (95%CI: 3.1; 8.4) after 1996: 1.5 (1.0; 2.0) respectively. For hypopharynx cancer the absolute number and ESR of LAD increased until 1997 and declined with 0.8% per year since 1997. Absolute numbers of patients with larynx cancer stayed stable over time, while ESR decreased (APC: −0.8 (95%CI: −1.1; −0.6)). Conclusion: The perception of an increasing trend in LAD in the Netherlands can be attributed to the increasing incidence of oral cavity and oropharynx carcinomas. For LAD of the hypopharynx a decreasing trend was observed. In larynx cancer, the proportional share of LAD of the larynx increased, even though incidence rates declined.</p
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