7,931 research outputs found
Review and synthesis of problems and directions for large scale geographic information system development
Problems and directions for large scale geographic information system development were reviewed and the general problems associated with automated geographic information systems and spatial data handling were addressed
Mathematical modelling of tissue-engineering angiogenesis
We present a mathematical model for the vascularisation of a porous scaffold following implantation in vivo. The model is given as a set of coupled non-linear ordinary differential equations (ODEs) which describe the evolution in time of the amounts of the different tissue constituents inside the scaffold. Bifurcation analyses reveal how the extent of scaffold vascularisation changes as a function of the parameter values. For example, it is shown how the loss of seeded cells arising from slow infiltration of vascular tissue can be overcome using a prevascularisation strategy consisting of seeding the scaffold with vascular cells. Using certain assumptions it is shown how the system can be simplified to one which is partially tractable and for which some analysis is given. Limited comparison is also given of the model solutions with experimental data from the chick chorioallantoic membrane (CAM) assay
An investigation into CLIL-related sections of EFL coursebooks : issues of CLIL inclusion in the publishing market
The current ELT global coursebook market has embraced CLIL as a weak form of bilingual education and an innovative component to include in General English coursebooks for EFL contexts. In this paper I investigate how CLIL is included in ELT coursebooks aimed at
teenaged learners, available to teachers in Argentina. My study is based on the content analysis of four series which include a section advertised as CLIL-oriented. Results suggest that such sections are characterised by (1) little correlation between featured subject specific content and school curricula in L1, (2) oversimplification of contents, and (3) dominance of reading skills development and lower-order thinking tasks. Through this study, I argue that
CLIL components become superficial supplements rather than a meaningful attempt to promote weak forms of bilingual education
Development of probabilistic models for quantitative pathway analysis of plant pest introduction for the EU territory
This report demonstrates a probabilistic quantitative pathway analysis model that can be used in risk assessment for plant pest introduction into EU territory on a range of edible commodities (apples, oranges, stone fruits and wheat). Two types of model were developed: a general commodity model that simulates distribution of an imported infested/infected commodity to and within the EU from source countries by month; and a consignment model that simulates the movement and distribution of individual consignments from source countries to destinations in the EU. The general pathway model has two modules. Module 1 is a trade pathway model, with a Eurostat database of five years of monthly trade volumes for each specific commodity into the EU28 from all source countries and territories. Infestation levels based on interception records, commercial quality standards or other information determine volume of infested commodity entering and transhipped within the EU. Module 2 allocates commodity volumes to processing, retail use and waste streams and overlays the distribution onto EU NUTS2 regions based on population densities and processing unit locations. Transfer potential to domestic host crops is a function of distribution of imported infested product and area of domestic production in NUTS2 regions, pest dispersal potential, and phenology of susceptibility in domestic crops. The consignment model covers the several routes on supply chains for processing and retail use. The output of the general pathway model is a distribution of estimated volumes of infested produce by NUTS2 region across the EU28, by month or annually; this is then related to the accessible susceptible domestic crop. Risk is expressed as a potential volume of infested fruit in potential contact with an area of susceptible domestic host crop. The output of the consignment model is a volume of infested produce retained at each stage along the specific consignment trade chain
Dynamics of Phononic Dissipation at the Atomic Scale: Dependence on Internal Degrees of Freedom
Dynamics of dissipation of a local phonon distribution to the substrate is a
key issue in friction between sliding surfaces as well as in boundary
lubrication. We consider a model system consisting of an excited nano-particle
which is weakly coupled with a substrate. Using three different methods we
solve the dynamics of energy dissipation for different types of coupling
between the nano-particle and the substrate, where different types of
dimensionality and phonon densities of states were also considered for the
substrate. In this paper, we present our analysis of transient properties of
energy dissipation via phonon discharge in the microscopic level towards the
substrate. Our theoretical analysis can be extended to treat realistic
lubricant molecules or asperities, and also substrates with more complex
densities of states. We found that the decay rate of the nano-particle phonons
increases as the square of the interaction constant in the harmonic
approximation.Comment: 10 pages, 6 figures, submitted to Phys. Rev.
Transport between edge states in multilayer integer quantum Hall systems: exact treatment of Coulomb interactions and disorder
A set of stacked two-dimensional electron systems in a perpendicular magnetic
field exhibits a three-dimensional version of the quantum Hall effect if
interlayer tunneling is not too strong. When such a sample is in a quantum Hall
plateau, the edge states of each layer combine to form a chiral metal at the
sample surface. We study the interplay of interactions and disorder in
transport properties of the chiral metal, in the regime of weak interlayer
tunneling. Our starting point is a system without interlayer tunneling, in
which the only excitations are harmonic collective modes: surface
magnetoplasmons. Using bosonization and working perturbatively in the
interlayer tunneling amplitude, we express transport properties in terms of the
spectrum for these collective modes, treating electron-electron interactions
and impurity scattering exactly. We calculte the conductivity as a function of
temperature, finding that it increases with increasing temperature as observed
in recent experiments. We also calculate the autocorrelation function of
mesoscopic conductance fluctuations induced by changes in a magnetic field
component perpendicular to the sample surface, and its dependence on
temperature. We show that conductance fluctuations are characterised by a
dephasing length that varies inversely with temperature.Comment: 13 pages, 10 figures, minor changes made for publicatio
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