Anomalous magnetophotoluminescence as a result of level repulsion in arrays of quantum dots

Selectively excited photoluminescence (SPL) of an array of self-organized In$_{0.5}$Ga$_{0.5}$As quantum dots has been measured in a magnetic field up to 11T. Anomalous magnetic field sensitivity of the SPL spectra has been observed under conditions for which the regular photoluminescence spectra is insensitive to the magnetic field due to large inhomogeneous broadening. The anomalous sensitivity is interpreted in terms of the repulsion of excited levels of the dots in a random potential. A theory presented to describe this phenomena is in excellent agreement with the experimental data. The data estimated the correlation in the positions of excited levels of the dots to be 94%. The magnetic field dependence allows the determination of the reduced cyclotron effective mass in a dot. For our sample we have obtained $m_em_h/(m_e+m_h)=0.034m_0$.Comment: 12 revtex preprint pages + 4 ps figures, uuencode

Home is where the heart of legal need is

AbstractPreliminary findings from the Legal Australia - Wide (LAW) Survey indicate that homeless people are an especially disadvantaged group who have increased vulnerability to a wide range of legal problems. The findings suggest that addressing the legal and non-legal needs of homeless people should be a priority and may require a holistic or client-focused approach, involving an integrated response from legal and broader human services

People

Postcard from Michaela Duffey, during the Linfield College Semester Abroad Program at Kanto Gakuin University in Yokohama, Japa

Towards run-time monitoring of web services conformance to business-level agreements

Web service behaviour is currently specified in a mixture of ways, often using methods that are only partially complete. These range from static functional specifications, based on interfaces in WSDL and preconditions in RIF, to business process simulations using executable process-based models such as BPEL, to detailed quality of service (QoS) agreements laid down in a service level agreement (SLA). This paper recognises that something similar to a SLA is required at the higher business level to govern the contract between service producers, brokers and consumers. We call this a business level agreement (BLA) and within this framework, seek to unify disparate aspects of functional specification, QoS and run-time verification. We propose that the method for validating a web service with respect to its advertised BLA should be based on run-time service monitoring. This is a position paper towards defining these goals

How good are projection methods for convex feasibility problems?

We consider simple projection methods for solving convex feasibility problems. Both successive and sequential methods are considered, and heuristics to improve these are suggested. Unfortunately, particularly given the large literature which might make one think otherwise, numerical tests indicate that in general none of the variants considered are especially effective or competitive with more sophisticated alternatives

People, place, enterprise: proceedings of the first annual conference on Olympic Legacy 8 and 9 May 2008

The Olympic Legacy: People, Place, Enterprise conference took place at the University of Greenwich in May 2008. The first in a series of annual conferences, it brought together leading academics, policy makers and practitioners to debate the lasting legacy of the games. The conference had four themes: social and cultural regeneration; Olympic tourism; enterprise, including social enterprise and skills development, and education, providing a multi-dimensional perspective on the likely impacts of the forthcoming London Olympics

Fresh-Register Automata

What is a basic automata-theoretic model of computation with names and fresh-name generation? We introduce Fresh-Register Automata (FRA), a new class of automata which operate on an infinite alphabet of names and use a finite number of registers to store fresh names, and to compare incoming names with previously stored ones. These finite machines extend Kaminski and Francez’s Finite-Memory Automata by being able to recognise globally fresh inputs, that is, names fresh in the whole current run. We exam-ine the expressivity of FRA’s both from the aspect of accepted languages and of bisimulation equivalence. We establish primary properties and connections between automata of this kind, and an-swer key decidability questions. As a demonstrating example, we express the theory of the pi-calculus in FRA’s and characterise bisimulation equivalence by an appropriate, and decidable in the finitary case, notion in these automata

Resurrecting the UK Historic Sector National Accounts

The UK national accounts do not provide a full long-run set of historic data describing the behaviour of the UK's private sector. Although comprehensive figures are available from 1987, the pre-1987 historic sector national accounts are marred by discontinuities, gaps and error. A partial solution is described that enables the compilation of consistent historic figures for sectors' income and expenditure flows, albeit at a high level of sector aggregation. Particular attention is paid to transfer incomes and associated inter-sector flows. To our knowledge, our dataset is the only one freely available that provides a basis, albeit an incomplete one, for a serious examination of Britain's post-war macroeconomic history. Coherent financial flow, balance sheet and volume data and further sector disaggregation are required to complete the picture. An annual dataset is provided as a supplement to the articleUK national accounts, European System of Accounts, data corruption, private sector, Statistics Commission

Analysis of enhanced diffusion in Taylor dispersion via a model problem

We consider a simple model of the evolution of the concentration of a tracer, subject to a background shear flow by a fluid with viscosity $\nu \ll 1$ in an infinite channel. Taylor observed in the 1950's that, in such a setting, the tracer diffuses at a rate proportional to $1/\nu$, rather than the expected rate proportional to $\nu$. We provide a mathematical explanation for this enhanced diffusion using a combination of Fourier analysis and center manifold theory. More precisely, we show that, while the high modes of the concentration decay exponentially, the low modes decay algebraically, but at an enhanced rate. Moreover, the behavior of the low modes is governed by finite-dimensional dynamics on an appropriate center manifold, which corresponds exactly to diffusion by a fluid with viscosity proportional to $1/\nu$