30,827 research outputs found
Towards a geographical information system for European economic community regional data
The study proposes the development of a geographical information system for European Economic Community (EEC) regional data. The features of geographical information systems and some related issues are discussed. An outline is given of likely user requirements and attempts by various European organisations to make provision for these. The practical work involves the application of three selected data analysis, manipulation and mapping packages, and operating system facilities to tasks which users of the data might wish to undertake. For this purpose, EEC "Level II" region boundaries were digitised, and selected socio-economic attributes for 1977 organised in disc files. Ten choropleth maps of the Level II regions (eight original variabels and two composite variables) are displayed. Although there is a lack of certain, more specialised features in the software system used, it is considered that there exists the imprtant basic requirements of data analysis, manipulation and mapping in package form, upon which to build the proposed geographical information system
Cognitive appraisal of dissertation stress among undergraduate students
The present study examined changes in primary and secondary appraisal, and coping strategies utilized in the final weeks leading to dissertation submission. Sixty volunteer Sports Studies dissertation students (male: n = 29; female: n = 31) completed an adapted Cognitive Appraisal of Health Scale (CAHS: Kessler, 1998), and Brief COPE (Carver, Scheier, & Weintraub, 1989) on 4 occasions over the 6 weeks before dissertation submission. Repeated measures multivariate analysis of variance indicated a significant main effect for gender, with no main effect for changes over time and no significant interaction effect. Results demonstrated that males perceived the dissertation to be significantly more threatening and iess challenging than females. With regard to coping, males used more active coping, positive reframing, planning, and acceptance of the stressor, with lower scores for self-blame, venting of emotions, and behavioral disengagement. The results suggest that, for this student population, the dissertation did not become increasingly stressful in the period before submission. Clear relationships were also evidenced between primary appraisal, secondary appraisal, and coping. Future research should seek to identify factors that moderate the influence of situational stressors on coping responses among undergraduate students
Electronic structure and magnetism in two-dimensional hexagonal 5d transition metal carbides, Tan+1Cn (n=1,2,3)
Density functional calculations are used to investigate the electronic
structure of two-dimensional 5d tantalum carbides with honeycomb-like lattice
structures. We focus on changes in the low-energy bands near the Fermi level
with dimensionality. We find that the Ta 5d states dominate, but the extended
nature of the wavefunctions makes them weakly correlated. The carbide sheets
are prone to long range magnetic order. We evaluate the stability of these
states to enhanced electron--electron interactions through a Hubbard U
correction. Lastly, we find spin orbit interactions strongly renormalize the
band structure for n=2, but play a minor role in n=1 and 3.Comment: 4 pages, 4 figure
Space Station Spartan study
The required extension, enhancement, and upgrading of the present Spartan concept are described to conduct operations from the space station using the station's unique facilities and operational features. The space station Spartan (3S), the free flyer will be deployed from and returned to the space station and will conduct scientific missions of much longer duration than possible with the current Spartan. The potential benefits of a space station Spartan are enumerated. The objectives of the study are: (1) to develop a credible concept for a space station Spartan; and (2) to determine the associated requirements and interfaces with the space station to help ensure that the 3S can be properly accommodated
Streakline flow visualization of discrete hole film cooling with holes inclined 30 deg to surface
Film injection from three rows of discrete holes angled 30 deg to the surface in line with mainstream flow and spaced 5 diameters apart in a staggered array was visualized by using helium bubbles as tracer particles. Both the main stream and the film injectant were ambient air. Detailed streaklines showing the turbulent motion of the film mixing with the main stream were obtained by photographing small, neutrally buoyant helium-filled soap bubbles which followed the flow field. The ratio of boundary layer thickness to hole diameter and the Reynolds number were typical of gas turbine film cooling applications. The results showed the behavior of the film and its interaction with the main stream for a range of blowing rates and two initial boundary layer thicknesses
Endomorphisms and automorphisms of locally covariant quantum field theories
In the framework of locally covariant quantum field theory, a theory is
described as a functor from a category of spacetimes to a category of
*-algebras. It is proposed that the global gauge group of such a theory can be
identified as the group of automorphisms of the defining functor. Consequently,
multiplets of fields may be identified at the functorial level. It is shown
that locally covariant theories that obey standard assumptions in Minkowski
space, including energy compactness, have no proper endomorphisms (i.e., all
endomorphisms are automorphisms) and have a compact automorphism group.
Further, it is shown how the endomorphisms and automorphisms of a locally
covariant theory may, in principle, be classified in any single spacetime. As
an example, the endomorphisms and automorphisms of a system of finitely many
free scalar fields are completely classified.Comment: v2 45pp, expanded to include additional results; presentation
improved and an error corrected. To appear in Rev Math Phy
Oocyte cryopreservation as an adjunct to the assisted reproductive technologies
The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included. See page 2 of PDF for this item.Keith L Harrison, Michelle T Lane, Jeremy C Osborn, Christine A Kirby, Regan Jeffrey, John H Esler and David Mollo
Causal sites as quantum geometry
We propose a structure called a causal site to use as a setting for quantum
geometry, replacing the underlying point set. The structure has an interesting
categorical form, and a natural "tangent 2-bundle," analogous to the tangent
bundle of a smooth manifold. Examples with reasonable finiteness conditions
have an intrinsic geometry, which can approximate classical solutions to
general relativity. We propose an approach to quantization of causal sites as
well.Comment: 21 pages, 3 eps figures; v2: added references; to appear in JM
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