Brucellosis in childhood in the Western Cape

Human brucellosis, a multisystem disease which may mimic other conditions, has a low incidence in childhood and the diagnosis may easily be missed. Over a 7-month period 9 children with brucellosis presented to the Department of Paediatrics and Child Health, Tygerberg Hospital. Six of the children had consumed unpasteurised milk. The main presenting symptoms were fever, fatigue, headache, myalgia and haematuria. Clinical signs included lymphadenopathy (3), nasopharyngitis (2), features of lower respiratory tract infection (2), splenomegaly (2) and pyrexia (1). The diagnosis was made on the basis of a positive serological titre (> 1:160) for Brucella abortus. The prozone phenomenon was encountered in 6 cases; however, the Coombs test confirmed the diagnosis in these cases. Children under 7 years were treated with co-trimoxazole and rifampicin and those over 7 years with tetracycline and rifampicin, for at least 6 weeks. No relapses were detected on follow-up

A deterministic detector for vector vortex states

Encoding information in high-dimensional degrees of freedom of photons has led to new avenues in various quantum protocols such as communication and information processing. Yet to fully benefit from the increase in dimension requires a deterministic detection system, e.g., to reduce dimension dependent photon loss in quantum key distribution. Recently, there has been a growing interest in using vector vortex modes, spatial modes of light with entangled degrees of freedom, as a basis for encoding information. However, there is at present no method to detect these non-separable states in a deterministic manner, negating the benefit of the larger state space. Here we present a method to deterministically detect single photon states in a four dimensional space spanned by vector vortex modes with entangled polarisation and orbital angular momentum degrees of freedom. We demonstrate our detection system with vector vortex modes from the |[Formula: see text]| = 1 and |[Formula: see text]| = 10 subspaces using classical and weak coherent states and find excellent detection fidelities for both pure and superposition vector states. This work opens the possibility to increase the dimensionality of the state-space used for encoding information while maintaining deterministic detection and will be invaluable for long distance classical and quantum communication

Radial orbit instability: review and perspectives

This paper presents elements about the radial orbit instability, which occurs in spherical self-gravitating systems with a strong anisotropy in the radial velocity direction. It contains an overview on the history of radial orbit instability. We also present the symplectic method we use to explore stability of equilibrium states, directly related to the dissipation induced instability mechanism well known in theoretical mechanics and plasma physics.Comment: 10 pages, submitted to Transport Theory and Statistical Physics, proceedings of Vlasovia 2009 International Conference. Corrected for typos, redaction, and references adde

Augmenting Distillation by Membranes: Developments and Prospects

The growing consciousness for sustainable industrial processes has resulted in industrially developed countries in supporting research efforts toward thorough evaluation of possibilities for improving efficiency of energy intensive separations implying also significant reduction of related carbon dioxide emissions. Being inherently thermodynamically inefficient, distillation, which is by far the most widely utilised and energy intensive separation technology in chemical process industries, has become primary target of energy conservation projects in refining, petrochemical and chemical industries. Improvement is an ongoing activity, replacing still beyond comprehension and a great deal of academic effort is oriented towards augmenting distillation by combining it, where appropriate, with membranes, i.e. pervaporation or vapour permeation, which in conjunction with polymeric membranes proved to be an industrially viable alternative to conventional processes for dehydration of alcohols. Present paper addresses recent developments along this line striving for larger fluxes in alcohol dehydrations by utilising ceramic membranes, with focus on vapour permeation, as well as the potential for the recovery of organic solvents and reactants forming azeotropes with other organics

Augmenting Distillation by Membranes: Developments and Prospects

The growing consciousness for sustainable industrial processes has resulted in industrially developed countries in supporting research efforts toward thorough evaluation of possibilities for improving efficiency of energy intensive separations implying also significant reduction of related carbon dioxide emissions. Being inherently thermodynamically inefficient, distillation, which is by far the most widely utilised and energy intensive separation technology in chemical process industries, has become primary target of energy conservation projects in refining, petrochemical and chemical industries. Improvement is an ongoing activity, replacing still beyond comprehension and a great deal of academic effort is oriented towards augmenting distillation by combining it, where appropriate, with membranes, i.e. pervaporation or vapour permeation, which in conjunction with polymeric membranes proved to be an industrially viable alternative to conventional processes for dehydration of alcohols. Present paper addresses recent developments along this line striving for larger fluxes in alcohol dehydrations by utilising ceramic membranes, with focus on vapour permeation, as well as the potential for the recovery of organic solvents and reactants forming azeotropes with other organics

Towards a formal description of the collapse approach to the inflationary origin of the seeds of cosmic structure

Inflation plays a central role in our current understanding of the universe. According to the standard viewpoint, the homogeneous and isotropic mode of the inflaton field drove an early phase of nearly exponential expansion of the universe, while the quantum fluctuations (uncertainties) of the other modes gave rise to the seeds of cosmic structure. However, if we accept that the accelerated expansion led the universe into an essentially homogeneous and isotropic space-time, with the state of all the matter fields in their vacuum (except for the zero mode of the inflaton field), we can not escape the conclusion that the state of the universe as a whole would remain always homogeneous and isotropic. It was recently proposed in [A. Perez, H. Sahlmann and D. Sudarsky, "On the quantum origin of the seeds of cosmic structure," Class. Quant. Grav. 23, 2317-2354 (2006)] that a collapse (representing physics beyond the established paradigm, and presumably associated with a quantum-gravity effect a la Penrose) of the state function of the inflaton field might be the missing element, and thus would be responsible for the emergence of the primordial inhomogeneities. Here we will discuss a formalism that relies strongly on quantum field theory on curved space-times, and within which we can implement a detailed description of such a process. The picture that emerges clarifies many aspects of the problem, and is conceptually quite transparent. Nonetheless, we will find that the results lead us to argue that the resulting picture is not fully compatible with a purely geometric description of space-time.Comment: 53 pages, no figures. Revision to match the published versio

Bi-Signature optical spectroscopy for online fault detection in electrical machines

A novel bi-signature optical spectroscopy for fault detection in electrical machines is presented. The combined use of long period grating (LPG) and two fibre Bragg gratings (FBG1 and FBG2) is implemented to discriminate between vibration and temperature sensitivity in the detection of machine faults. With LPG having higher sensitivity to temperature compared to both FBGs, machine faults are detected through spectral analysis of both signatures; and the optimal detection signature for each fault is consequently analysed. This novel technique utilises the principle of a shift in the wavelengths of the gratings to determine the kind of fault present in an electrical machine as the signature spectroscopy reveals varying amount of Bragg wavelength shifts for various fault types. The use of FBG sensing for fault detection in electrical machines has the potential of revolutionising non-intrusive real-time condition monitoring of future industrial machines with high reliability due to zero electromagnetic interference (EMI) as well as significant low cost of fibre-optic sensors

Enantioselective adsorption of ibuprofen and lysine in metal-organic frameworks

This study reveals the efficient enantiomeric separation of bioactive molecules in the liquid phase. Chiral structure HMOF-1 separates racemic mixtures whereas heteroselectivity is observed for scalemic mixtures of ibuprofen using non-chiral MIL-47 and MIL-53. Lysine enantiomers are only separated by HMOF-1. These separations are controlled by the tight confinement of the molecules

Novel characterization techniques for cultural heritage using a TEM orientation imaging in combination with 3D precession diffraction tomography: a case study of green and white ancient Roman glass tesserae

We present new transmission electron microscopy (TEM) based electron diffraction characterization techniques (orientation imaging combined with 3D precession electron diffraction tomography-ADT) applied on cultural heritage materials. We have determined precisely unit cell parameters, crystal symmetry, atomic structure, and orientation/phase mapping of various pigment/opacifier crystallites at nm scale which are present in green and white Roman glass tesserae. Such TEM techniques can be an alternative to Synchrotron based techniques, and allow to distinguish accurately at nm scale between different crystal structures even in cases of same/very close chemical composition, where is also possible to visualize between different crystal orientations and amorphous/crystalline phases. This study additionally demonstrates that although opacifiers in green and white tesserae are found to have average Pb2Sb2O7 cubic and CaSb2O6 trigonal structures, their pyrochlore related framework can host many other elements like Cu, Ca, Fe through ionic exchanges at high firing temperatures which in turn may also contribute to the tesserae colour appearance

Circumbinary, not transitional: on the spiral arms, cavity, shadows, fast radial flows, streamers, and horseshoe in the HD 142527 disc

We present 3D hydrodynamical models of the HD142527 protoplanetary disc, a bright and well-studied disc that shows spirals and shadows in scattered light around a 100 au gas cavity, a large horseshoe dust structure in mm continuum emission, together with mysterious fast radial flows and streamers seen in gas kinematics. By considering several possible orbits consistent with the observed arc, we show that all of the main observational features can be explained by one mechanism - the interaction between the disc and the observed binary companion. We find that the spirals, shadows, and horseshoe are only produced in the correct position angles by a companion on an inclined and eccentric orbit approaching periastron - the 'red' family from Lacour et al. Dust-gas simulations show radial and azimuthal concentration of dust around the cavity, consistent with the observed horseshoe. The success of this model in the HD142527 disc suggests other mm-bright transition discs showing cavities, spirals, and dust asymmetries may also be explained by the interaction with central companions