Predictions of the solar wind interaction with Comet Grigg-Skjellerup

The planned encounter of the Giotto spacecraft with comet Grigg-Skjellerup on 10th July 1992 promises to extend our knowledge of the solar wind interaction with comets substantially. While there have been spacecraft missions to comets before now, this mission is exploratory in the sense that the target comet is much older and there-fore it has a much lower gas production rate than comets Halley (by a factor approximately 200) or Giacobini-Zinner (factor approximately 10). Here we present theoretical predictions for the location of the bow shock and contact surface features, and compare similar predictions with the observed features at the previous encounters. We discuss the applicability of fluid-type theory which these models employ, in the case of strong and weak comets in the solar wind

High surface area, emulsion-templated carbon foams by activation of polyHIPEs derived from Pickering emulsions.

Carbon foams displaying hierarchical porosity and excellent surface areas of >1400 m2/g can be produced by the activation of macroporous poly(divinylbenzene). Poly(divinylbenzene) was synthesized from the polymerization of the continuous, but minority, phase of a simple high internal phase Pickering emulsion. By the addition of KOH, chemical activation of the materials is induced during carbonization, producing Pickering-emulsion templated carbon foams, or carboHIPEs, with tailorable macropore diameters and surface areas almost triple that of those previously reported. The retention of the customizable, macroporous open-cell structure of the poly(divinylbenzene) precursor and the production of a large degree of microporosity during activation leads to tailorable carboHIPEs with excellent surface areas

Who flees? An integration of household characteristics in the white flight hypothesis

Although there is an extensive field dedicated to the study of ethnic residential segregation, few scholars investigate the importance of household characteristics for understanding this segregation. Considering the White Flight hypothesis as a special case of the Residential Stress theory, we investigate whether there is a link between the presence of four different house hold types ethnic concentration and segregation. We therefore perform two analyses using the 2001 Census of Belgium: a binary logistic multilevel analysis investigating the chance that a neighbourhood is ethnically concentrated (i.e. has a location quotient higher than 1) and a single level linear regression analysis investigating the dissimilarity score of a city. We find that neighbourhoods with a large share ethnic majority single households and lone parents have a higher chance to be concentrated than neighbourhoods with a lower share of either household type. The same can be said for the percentage cohabitating, childless couples before adding control variables. The percentage families with young children has an inverse relation with neighbourhood concentration before adding control variables. Cities with a higher share families with young children are more segregated than cities with a lower share families with young children. Cities with a high share single households and lone parents, on the other hand, are less segregated than cities with a low share single households or lone parents. We thus conclude that it is important to consider household characteristics when studying White Flight specifically and ethnic residential segregation more general

Measurement of Permanent Electric Dipole Moments of Charged Hadrons in Storage Rings

Permanent Electric Dipole Moments (EDMs) of elementary particles violate two fundamental symmetries: time reversal invariance (T) and parity (P). Assuming the CPT theorem this implies CP-violation. The CP-violation of the Standard Model is orders of magnitude too small to be observed experimentally in EDMs in the foreseeable future. It is also way too small to explain the asymmetry in abundance of matter and anti-matter in our universe. Hence, other mechanisms of CP violation outside the realm of the Standard Model are searched for and could result in measurable EDMs. Up to now most of the EDM measurements were done with neutral particles. With new techniques it is now possible to perform dedicated EDM experiments with charged hadrons at storage rings where polarized particles are exposed to an electric field. If an EDM exists the spin vector will experience a torque resulting in change of the original spin direction which can be determined with the help of a polarimeter. Although the principle of the measurement is simple, the smallness of the expected effect makes this a challenging experiment requiring new developments in various experimental areas. Complementary efforts to measure EDMs of proton, deuteron and light nuclei are pursued at Brookhaven National Laboratory and at Forschungszentrum Juelich with an ultimate goal to reach a sensitivity of 10^{-29} e cm.Comment: 8 pages, 2 figure

COMBINING TUBERCULOSIS AND LEPROSY SERVICES IN ONE PROGRAMME

ABSTRACT Reasons are provided for considering combining the services for leprosy and tuberculosis in one programme. Advantages and disadvantages of the combination are reviewed for leprosy and for tuberculosis separately. The place of a partly integrated special programme in general services with a primary health care concept is indicated and the potentially important role of the community health agent briefly described