Eigenvalue distributions from a star product approach

We use the well-known isomorphism between operator algebras and function spaces equipped with a star product to study the asymptotic properties of certain matrix sequences in which the matrix dimension $D$ tends to infinity. Our approach is based on the $su(2)$ coherent states which allow for a systematic 1/D expansion of the star product. This produces a trace formula for functions of the matrix sequence elements in the large-$D$ limit which includes higher order (finite-$D$) corrections. From this a variety of analytic results pertaining to the asymptotic properties of the density of states, eigenstates and expectation values associated with the matrix sequence follows. It is shown how new and existing results in the settings of collective spin systems and orthogonal polynomial sequences can be readily obtained as special cases. In particular, this approach allows for the calculation of higher order corrections to the zero distributions of a large class of orthogonal polynomials.Comment: 25 pages, 8 figure

Duality constructions from quantum state manifolds

The formalism of quantum state space geometry on manifolds of generalised coherent states is proposed as a natural setting for the construction of geometric dual descriptions of non-relativistic quantum systems. These state manifolds are equipped with natural Riemannian and symplectic structures derived from the Hilbert space inner product. This approach allows for the systematic construction of geometries which reflect the dynamical symmetries of the quantum system under consideration. We analyse here in detail the two dimensional case and demonstrate how existing results in the AdS_2/CFT_1 context can be understood within this framework. We show how the radial/bulk coordinate emerges as an energy scale associated with a regularisation procedure and find that, under quite general conditions, these state manifolds are asymptotically anti-de Sitter solutions of a class of classical dilaton gravity models. For the model of conformal quantum mechanics proposed by de Alfaro et. al. the corresponding state manifold is seen to be exactly AdS_2 with a scalar curvature determined by the representation of the symmetry algebra. It is also shown that the dilaton field itself is given by the quantum mechanical expectation values of the dynamical symmetry generators and as a result exhibits dynamics equivalent to that of a conformal mechanical system.Comment: 25 Pages, References Adde

The problem of theory and practice in the medical profession1

Scientific knowledge is a symbolic system consisting of hypotheses, models and theories generated by means of a paradigm-mediated interaction between a scientific community and a research domain. Such a knowledge generating paradigm consists of already existing theories, as well as methodological and ontological beliefs or assumptions. In this article it is argued that the meaning ascribed to the central concepts of medical science(such as patient, disease, causality and therapy) are fundamentally determined by the 19th century logical positivist scientific paradigm. The ontological and methodological implications of the postmodern natural sciences (e.g. quantum physics) have not been applied to medical science. The 19th century ‘natural science paradigm’ therefore acts as a metatheory for both medical science and medical practice. However, the theoretical knowledge system generated by medical science acts as the theory for the practice of scientific clinical medicine which therefore functions with the same understanding of the central concepts such as patient, disease and disease causality, therapy etc. The limitations of this paradigmatic monism are illustrated by an analysis of the medical and societal response to the AIDS epidemic and it is concluded that medical science and practice, because of the complexity o f its research and practice domain, must accept in principle the possibility of paradigmatic pluralism (as in the social sciences) or should attempt to develop a holistic paradigm that will cope more adequately with its fields of research and practice

4-(3-Azaniumylpropyl)morpholin-4-ium chloride hydrogen oxalate: An unusual example of a dication with different counter-anions

© 2014 International Union of Crystallography. The mixed organic-inorganic title salt, C7H18N2O2+·C2HO4-·Cl-, forms an assembly of ionic components which are stabilized through a series of hydrogen bonds and charge-assisted intermolecular interactions. The title assembly crystallizes in the monoclinic C2/c space group with Z = 8. The asymmetric unit consists of a 4-(3-azaniumylpropyl)morpholin-4-ium dication, a hydrogen oxalate counter-anion and an inorganic chloride counter-anion. The organic cations and anions are connected through a network of N - H⋯O, O - H⋯O and C - H⋯O hydrogen bonds, forming several intermolecular rings that can be described by the graph-set notations R33(13), R21(5), R12(5), R21(6), R23(6), R22(8) and R33(9). The 4-(3-azaniumylpropyl)morpholin-4-ium dications are interconnected through N - H⋯O hydrogen bonds, forming C(9) chains that run diagonally along the ab face. Furthermore, the hydrogen oxalate anions are interconnected via O - H⋯O hydrogen bonds, forming head-to-tail C(5) chains along the crystallographic b axis. The two types of chains are linked through additional N - H⋯O and O - H⋯O hydrogen bonds, and the hydrogen oxalate chains are sandwiched by the 4-(3-azaniumylpropyl)morpholin-4-ium chains, forming organic layers that are separated by the chloride anions. Finally, the layered three-dimensional structure is stabilized via intermolecular N - H⋯Cl and C - H⋯Cl interactions

Symptomatology and Anatomy of Stemgrooving (Legno Riccio) 1n the Grape Vine

External and anatomical differences between organs affected and unaffected by stemgrooving were studied on the wine grape cultivar Chenin blanc and the table grape cultivars Barlinka and Almeria. Cultivar susceptibility, graft transmissibility as well as the effect of the disease on the percentage of take and growth in: the nursery were studied. The probability of an association with other virus diseases was considered. Abnormal behaviour of the vascular cambium of infected vines gave rise to hypertrophy, hyperplasia, hypoplasia and parenchymatoses in the secondary xylem and phloem. In diseased tissues dift'erentiation of pbeDogen proceeded abnormally deep into the phloem rays. Graft transmission was detected anatomically within six months. The disease was found in all the vine growing districts of the Western Cape. Anatomical.studies showed that the disease had been present for many years. A negative effect on the percentage of t:'tKe and growth in the nursery was, recorded. A probable-relationship with corky bark was indicated anatomically and by indexing with LN33

Growth or decay: universality of the turbulent dynamo saturation

The small-scale turbulent dynamo (SSD) is likely to be responsible for the magnetisation of the interstellar medium (ISM) that we observe in the Universe today. The SSD efficiently converts kinetic energy $E_{\rm kin}$ into magnetic energy $E_{\rm mag}$, and is often used to explain how an initially weak magnetic field with $E_{\rm mag} \ll E_{\rm kin}$ is amplified, and then maintained at a level $E_{\rm mag} \lesssim E_{\rm kin}$. Usually, this process is studied by initialising a weak seed magnetic field and letting the turbulence grow it to saturation. However, in this study, using three-dimensional, non-ideal magnetohydrodynamical turbulence simulations, we show that the same saturated state can also be achieved if initially $E_{\rm mag} \gg E_{\rm kin}$ or $E_{\rm mag} \sim E_{\rm kin}$. This is realised through a two-stage exponential decay (1. a slow backreaction that converts $E_{\rm mag}$ into $E_{\rm kin}$, and 2. Ohmic dissipation concentrated in anisotropic current sheets) into the saturated state, for which we provide an analytical model. This means that even if there are temporary local enhancements of $E_{\rm mag}$ in the ISM, such that $E_{\rm mag} > E_{\rm kin}$, e.g., through amplifications such as compressions, over a long enough time the field will decay into the saturated state set by the SSD, which is determined by the turbulence and magnetic dissipation. However, we also provide analytical models for the decay times and utilise wait-time statistics from compressive supernova events to show that if the magnetic field is enhanced above the saturated state, it will not have enough time to decay the field before the next supernova event. Hence, unless there exists a mechanism for destroying magnetic fields that is not in our non-ideal MHD models, the amplitudes of interstellar magnetic fields may also be a... (abridged).Comment: 18 pages. 14 figures. Submitted to MNRAS. Comments welcom

Fundamental MHD scales -- II: the kinematic phase of the supersonic small-scale dynamo

The small-scale dynamo (SSD) amplifies weak magnetic fields exponentially fast via kinetic motions. While there exist well-established theories for SSDs in incompressible flows, many astrophysical SSDs operate in supersonic turbulence. To understand the impact of compressibility on amplified magnetic fields, we perform an extensive set of visco-resistive SSD simulations, covering a wide range of sonic Mach number $\mathcal{M}$, hydrodynamic Reynolds number Re, and magnetic Prandtl number Pm. We develop robust methods for measuring kinetic and magnetic energy dissipation scales $\ell_\nu$ and $\ell_\eta$, as well as the scale at which magnetic fields are strongest $\ell_p$ during the kinematic phase of these simulations. We show that $\ell_\nu/\ell_\eta \sim$ Pm$^{1/2}$ is a universal feature in the kinematic phase of Pm $\geq 1$ SSDs, regardless of $\mathcal{M}$ or Re, and we confirm earlier predictions that SSDs operating in incompressible plasmas (either $\mathcal{M} \leq 1$ or Re $<$ Re$_{\rm crit} \approx 100$) concentrate magnetic energy at the smallest scales allowed by magnetic dissipation, $\ell_p \sim \ell_\eta$, and produce fields organised with field strength and field-line curvature inversely correlated. However, we show that these predictions fail for compressible SSDs ($\mathcal{M} > 1$ and Re $>$ Re$_{\rm crit}$), where shocks concentrate magnetic energy in large-scale, over-dense, coherent structures, with size $\ell_p \sim (\ell_{\rm turb} / \ell_{\rm shock})^{1/3} \ell_\eta \gg \ell_\eta$, where $\ell_{\rm shock} \sim \mathcal{M}^2 / [$Re $(\mathcal{M} - 1)^2]$ is shock width, and $\ell_{\rm turb}$ is the turbulent outer scale; magnetic field-line curvature becomes almost independent of the field strength. We discuss the implications for galaxy mergers and for cosmic-ray transport models in the interstellar medium that are sensitive to field-line curvature statistics.Comment: 25 pages, 15 figures, submitted to MNRAS, json-file w/ dat

Availability of infective larvae of parasitic nematodes of sheep grazing on Kikuyu (Pennisetum clandestinum) pastures in the winter rainfall area

Thirteen groups of 4 South African mutton Merinos grazed for 4 weeks with the flock on Kikuyu pastures and were slaughtered for total and differential worm counts at necropsy. Subsequently 12 groups of 8 week tracers grazed on the pastures and were killed for worm counts post mortem. The following were present in most sheep: Teladorsagia (syn. Ostertagia) circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Dictyocaulus filaria and Oesophagostomum venulosum. Haemonchus contortus, Nematodirus spathiger and Trichuris skrjabini were less frequently recovered. Optimal conditions for infestation of grazing sheep occurred from June (late autumn)-October (spring) when mean temperatures in any 4 week period were 40 mm of rain fell on 8 or more separate days. When the mean temperatures exceeded 20 °C pastures were safe, sheep acquiring< 1 000 worms in 4 weeks.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201

The outcome of babies 'of mothers with severe Rhesus incompatibility treated at Tygerberg Hospital, 1980 - 1993

No Abstract

Parasites in sheep grazing on Kikuyu (Pennisetum clandestinum) pastures in the winter rainfall region

Regular worm counts were done post-mortem on sheep that had grazed on Kikuyu pastures at the Elsenburg Research Station near Stellenbosch, a winter rainfall region. Major species were Trichostrongylus colubriformis, Trichostrongylus axei, while Ostertagia circumcincta was usually present in large numbers. Minor species were Haemonchus contortus, Nematodirus spathiger, Dictyocaulus filaria , Oesophagostomum venulosum, Trichuris spp., Chabertia ovina and larvae of the arthropod Oestrus ovis. Muellerius capillaris caused the formation of nodules in the lungs but were not counted. The trial started in April1982 and was concluded in March 1984. One hundred and four sheep died or were slaughtered and 99 were examined post-mortem during this period. Total worm burdens rose to a peak of 88 763 (range 67 281-124 735) worms in March 1983, i.e. sheep mortality was such that the flock had to be treated with an anthelmintic in April 1983 to prevent further losses. Kikuyu pastures provide shade, form an excellent mat, the humus layer under the grass retains moisture and is an excellent incubator for preinfective larvae and a protector for infective larvae. If these qualities are combined with more than 100 mm of rain in spring and summer, Kikuyu pastures are a paradise for the free-living stages.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201