Multi-excitons in self-assembled InAs/GaAs quantum dots: A pseudopotential, many-body approach

We use a many-body, atomistic empirical pseudopotential approach to predict the multi-exciton emission spectrum of a lens shaped InAs/GaAs self-assembled quantum dot. We discuss the effects of (i) The direct Coulomb energies, including the differences of electron and hole wavefunctions, (ii) the exchange Coulomb energies and (iii) correlation energies given by a configuration interaction calculation. Emission from the groundstate of the $N$ exciton system to the $N-1$ exciton system involving $e_0\to h_0$ and $e_1\to h_1$ recombinations are discussed. A comparison with a simpler single-band, effective mass approach is presented

Older people's experiences of changed medication appearance : a survey

This report details a survey of older people's experiences of changed medication appearance. The aims of the study were: • To develop a questionnaire in partnership with older people to survey older people’s views on fluctuating medication appearance • To elicit older people’s experiences of medication that changed appearance due to ‘generic prescribing’ and ‘parallel import’ practices and its impact on their medication taking practices. These common pharmacy practices mean that the same tablet medication can be issued to older people in different colours, sizes and shapes to their previous prescriptions. Older people from a local User/Carer Forum highlighted these problems to the research team and asked that we investigate to explore the extent of the problem. An eight-item questionnaire was developed and distributed to 2000 older people (50 years+) across participating PCTs in Greater Manchester in 2008. A 29% response rate was achieved. The data was analysed using the SPSS statistical package. Findings include: •63.3% experienced a change in the appearance of their tablet medications. •74.1% did not seek advice regarding the change in the appearance of their tablet medications. •Older people noted changes to the actual tablets, tablet packaging and written information that accompanies tablets. Changes are occurring to the colour, size and shape of tablets more than changes to packaging and written information. The majority of respondents had experienced changes in the appearance of their prescribed tablet medication in the previous two years which were not due to change in medication or dose etc. Worryingly, for some respondents, these changes prompted negative experiences such as anxiety, confusion and upset. Of particular concern was that a small number omitted the affected tablet medications and did not seek help or advice from GPs, pharmacists or relatives. Six older people have been study advisors from inception to dissemination of this study and significantly added to its quality. The study demonstrates substantive public engagement / user involvement in research. The findings suggest nurses and others have a role to play in promoting better medicines management and identifying those most at risk from changed appearance of medications

Composite Geometric Phase for Multipartite Entangled States

When an entangled state evolves under local unitaries, the entanglement in the state remains fixed. Here we show the dynamical phase acquired by an entangled state in such a scenario can always be understood as the sum of the dynamical phases of its subsystems. In contrast, the equivalent statement for the geometric phase is not generally true unless the state is separable. For an entangled state an additional term is present, the mutual geometric phase, that measures the change the additional correlations present in the entangled state make to the geometry of the state space. For $N$ qubit states we find this change can be explained solely by classical correlations for states with a Schmidt decomposition and solely by quantum correlations for W states.Comment: 4 pages, 1 figure, improved presentation, results and conclusions unchanged from v1. Accepted for publication in PR

Anomalous Radio-Wave Scattering from Interstellar Plasma Structures

This paper considers scattering screens that have arbitrary spatial variations of scattering strength transverse to the line of sight, including screens that are spatially well confined, such as disks and filaments. We calculate the scattered image of a point source and the observed pulse shape of a scattered impulse. The consequences of screen confinement include: (1) Source image shapes that are determined by the physical extent of the screen rather than by the shapes of much-smaller diffracting microirregularities. These include image elongations and orientations that are frequency dependent. (2) Variation with frequency of angular broadening that is much weaker than the trademark \nu^{-2} scaling law (for a cold, unmagnetized plasma), including frequency-independent cases; and (3) Similar departure of the pulse broadening time from the usually expected \nu^{-4} scaling law. We briefly discuss applications that include scattering of pulses from the Crab pulsar by filaments in the Crab Nebula; image asymmetries from Galactic scattering of the sources Cyg X-3, Sgr A*, and NGC 6334B; and scattering of background active galactic nuclei by intervening galaxies. We also address the consequences for inferences about the shape of the wavenumber spectrum of electron density irregularities, which depend on scaling laws for the image size and the pulse broadening. Future low-frequency (< 100 MHz) array observations will also be strongly affected by the Galactic structure of scattering material. Our formalism is derived in the context of radio scattering by plasma density fluctuations. It is also applicable to optical, UV and X-ray scattering by grains in the interstellar medium.Comment: 21 pages, LaTeX2e with AASTeX-4.0, 6 PostScript figures, accepted by ApJ, revised version has minor changes to respond to referee comments and suggestion

Design and validation of a low cost indoor environment quality data logger

Theme: Fifty years later: Revisiting the role of architectural science in design and practiceThe appraisal of indoor environment quality in residential dwellings presents a range of technical challenges. Indoor environment quality (IEQ) is often described as having thermal, visual, aural and olfactory dimensions, each of which is assessed subjectively by the resident. While it is possible to objectively assess physical parameters relating to each aspect of IEQ, either directly or indirectly, resident satisfaction with the environment is determined subjectively so must be inferred. In the field study of thermal comfort (FSTC) approach, objective physical measurements are collected simultaneously with resident preference and sensation information, usually via a diary or written survey. This research paper explores a new approach to residential IEQ appraisal which extends the FSTC approach to the visual, aural and olfactory dimensions using a low cost data collection system based upon the Arduino microcontroller platform. The paper describes the design developed, presents early validation results and draws preliminary conclusions.Andrew Carre, Terence Williamson and Veronica Soebart