Linear root water uptake by vegetation

The performance of a simple model with a linear root water extraction term that varies with time is presented in this paper. The research is based on the use of a one-dimensional form of Richard’s Equation for unsaturated moisture flow including a sink term. A numerical solution has been achieved via the finite element method for spatial discretisation along with a finite difference time-marching scheme. The model is assessed via a series of simulations of water uptake beneath uniform crop cover. A good correlation between the field data and simulated results has been achieved. This relatively straight forward approach is seemed more suitable for development and application to a range of geoengineering problems such as slope stability, shrinkage and heave prediction

Creep in fibre-reinforced polymer mat composites

Tensile creeps have been conducted upon a woven, glass-fibre laminated epoxy composite and a 0/90° cross ply, carbon fibre reinforced epoxy composite. For the laminate loading was aligned with a fibre direction. For the ply the loading was inclined to the fibres (off-axis). Testing to stress levels up to 200 MPa and temperatures in the range 20°- 200°C has revealed a form of creep in each material. The creep observed is essentially primary in nature but with extended time •1000 h, it may exhaust or resemble a pseudo-secondary regime with a low rate. Where the load carrying capacity is lost, through fibre breakage or tab slip, the creep rate accelerates suddenly to infinity in a few hours. Smooth creep curves apply to successful tests but many irregular curves resulted from grip failure. A phenomenological approach was used to model smooth curves using a summation of instantaneous, primary and secondary strain terms. For the mat reinforcement a consistent trend was not found between the secondary creep rate and a stress that was raised incrementally upon the same testpiece. However the cumulative instantaneous strain provided the correct elastic modulus. Creep in the solid laminate was believed to be due to a fibre straightening that yielded a limiting strain in a time beyond which the process exhausts. Creep in cfrc was only evident when the fibres were inclined to the stress axis, indicating a viscous flow in the matrix. Moreover, it is believed that a viscous shear sliding between laminates or plies is more likely to contribute to an off-axis deformation mode which is not strain limited.http://www.brunel.ac.uk/about/acad/sed/sedstaff/design/DavidRee

Measuring Confidentiality Risks in Census Data

Two trends have been on a collision course over the recent past. The first is the increasing demand by researchers for greater detail and flexibility in outputs from the decennial Census of Population. The second is the need felt by the Census Offices to demonstrate more clearly that Census data have been explicitly protected from the risk of disclosure of information about individuals. To reconcile these competing trends the authors propose a statistical measure of risks of disclosure implicit in the release of aggregate census data. The ideas of risk measurement are first developed for microdata where there is prior experience and then modified to measure risk in tables of counts. To make sure that the theoretical ideas are fully expounded, the authors develop small worked example. The risk measure purposed here is currently being tested out with synthetic and a real Census microdata. It is hoped that this approach will both refocus the census confidentiality debate and contribute to the safe use of user defined flexible census output geographies

Internal Migration and Regional Population Dynamics in Europe: Denmark Case Study

This report analyses the patterns of internal migration and population change across the communes of Denmark as part of a multi-country study of regional population dynamics in Europe, comparing the 1980s and 1990s. Section 2 of the report reviews the recent history of internal migration and regional/local population change in Denmark. Section 3 documents data sources and structure. Section 4 provides a detailed cartographic analysis of the patterns of in-migration, out-migration and net-migration at commune level for 1985 and 1998 (the years selected for study), while section 5 reviews population change between 1985 and 1998. Overall net migration shifts have decreased between the two years. The spatial pattern combines losses from peripheral regions (western Jutland, Bornholm) and Copehagen suburbs with gains to commuting belts centred on Copenhagen and the other large towns. As many other high income European countries, there is a profound contrast between the migration behaviour of young people and other adults (families, older workers and the retired). Young people move strongly towards the centre of the capital region and other large towns, while the other groups deconcentrate. Section 6 analyses the relationships between net migration/population change and the settlement system, to calibrate more precisely the patterns observed on the maps, while sections 7 and 8 look at the relationships between internal migration and economic/functional classifications of the communes. The former relationships are stronger than the latter, but are not as well clearly structured with respect to the urban hierarchy or population density as in many other countries studied. Denmark has reached a system state beyond simple counterurbanisation to be characterised by periurbanisation in the Copenhagen region, reurbanisation in Copenhagen itself and moderate outflows from rural regions

Stellar Dynamics around Black Holes in Galactic Nuclei

We classify orbits of stars that are bound to central black holes in galactic nuclei. The stars move under the combined gravitational influences of the black hole and the central star cluster. Within the sphere of influence of the black hole, the orbital periods of the stars are much shorter than the periods of precession. We average over the orbital motion and end up with a simpler problem and an extra integral of motion: the product of the black hole mass and the semimajor axis of the orbit. Thus the black hole enforces some degree of regularity in its neighborhood. Well within the sphere of influence, (i) planar, as well as three dimensional, axisymmetric configurations-both of which could be lopsided-are integrable, (ii) fully three dimensional clusters with no spatial symmetry whatsover must have semi-regular dynamics with two integrals of motion. Similar considerations apply to stellar orbits when the black hole grows adiabatically. We introduce a family of planar, non-axisymmetric potential perturbations, and study the orbital structure for the harmonic case in some detail. In the centered potentials there are essentially two main families of orbits: the familiar loops and lenses, which were discussed in Sridhar and Touma (1997, MNRAS, 287, L1-L4). We study the effect of lopsidedness, and identify a family of loop orbits, whose orientation reinforces the lopsidedness, an encouraging sign for the construction of self-consistent models of eccentric, discs around black holes, such as in M31 and NGC 4486B.Comment: to appear in MNRAS, 10 pages, latex, 20 POstScript figure

The human superior colliculus: Neither necessary, nor sufficient for consciousness?

Non-invasive neuroimaging in humans permits direct investigation of the potential role for mesodiencephalic structures in consciousness. Activity in the superior colliculus can be correlated with the contents of consciousness, but it can be also identified for stimuli of which the subject is unaware; and consciousness of some types of visual stimuli may not require the superior colliculus

The importance of incorporating technological advancements into the artificial eye process: a perspective commentary

Application of technology into healthcare has typically been targeted to high demand illnesses and treatments. However, with an increasing need to meet patient’s expectations combined with increased accessibility and reduced costs, smaller healthcare fields are starting to investigate its function and usability. Services have historically been led by skills and expertise, and recent developments are being seen by ocularists in the field of prosthetic eyes who acknowledge the potential benefit from technological advancement. Utilising the technologies recently investigated in maxillofacial prosthesis can start the evolutionary process where products are continually re-designed and re-developed to achieve excellent patient outcome and satisfaction levels