Diffuse interstellar bands in Upper Scorpius: Probing variations in the DIB spectrum due to changing environmental conditions

We study the effects of local environmental conditions affecting the diffuse interstellar band (DIB) carriers within the Upper Scorpius subgroup of the Sco OB2 association. We obtained optical spectra with FEROS, and measured the equivalent widths of five DIBs (at 5780, 5797, 6196, 6379, and 6613 Angstrom) as well as those of absorption lines of di-atomic molecules (CH, CH+, CN) and atoms (KI, CaI) towards 89 targets in the direction of Upper Scorpius. We construct a simple radiative transfer and chemical network model of the diffuse interstellar medium (ISM) sheet in front of Upp Sco to infer the effective radiation field. Both the interstellar radiation field strength, I_UV, and the molecular hydrogen fraction, f_H2, have been derived for 55 sightlines probing the Upp Sco ISM. We discuss the relations between DIB strengths, CH and CH+ line strengths, E(B-V), I_UV, and f_H2. The ratio between the 5780 and 5797 DIBs reveals a (spatial) dependence on the local environment in terms of cloud density and exposure to the interstellar radiation field, reflecting the molecular nature of these DIB carriers.Comment: accepted for publication in A&A. 19 pages, 25 figures main paper. 26 pages appendix. v2. Minor revision

Procedural and documentation variations in intravenous infusion administration: a mixed methods study of policy and practice across 16 hospital trusts in England

Background: Procedural and documentation deviations relating to intravenous (IV) infusion administration can have important safety consequences. However, research on such deviations is limited. To address this we investigated the prevalence of procedural and documentation deviations in IV infusion administration and explored variability in policy and practice across different hospital trusts. / Methods: We conducted a mixed methods study. This involved observations of deviations from local policy including quantitative and qualitative data, and focus groups with clinical staff to explore the causes and contexts of deviations. The observations were conducted across five clinical areas (general medicine, general surgery, critical care, paediatrics and oncology day care) in 16 National Health Service (NHS) trusts in England. All infusions being administered at the time of data collection were included. Deviation rates for procedural and documentation requirements were compared between trusts. Local data collectors and other relevant stakeholders attended focus groups at each trust. Policy details and reasons for deviations were discussed. / Results: At least one procedural or documentation deviation was observed in 961 of 2008 IV infusions (deviation rate 47.9%; 95% confidence interval 45.5–49.8%). Deviation rates at individual trusts ranged from 9.9 to 100% of infusions, with considerable variation in the prevalence of different types of deviation. Focus groups revealed lack of policy awareness, ambiguous policies, safety and practicality concerns, different organisational priorities, and wide variation in policies and practice relating to prescribing and administration of IV flushes and double-checking. / Conclusions: Deviation rates and procedural and documentation requirements varied considerably between hospital trusts. Our findings reveal areas where local policy and practice do not align. Some policies may be impractical and lack utility. We suggest clearer evidence-based standardisation and local procedures that are contextually practical to address these issues

Synthesis and Optimization of Reversible Circuits - A Survey

Reversible logic circuits have been historically motivated by theoretical research in low-power electronics as well as practical improvement of bit-manipulation transforms in cryptography and computer graphics. Recently, reversible circuits have attracted interest as components of quantum algorithms, as well as in photonic and nano-computing technologies where some switching devices offer no signal gain. Research in generating reversible logic distinguishes between circuit synthesis, post-synthesis optimization, and technology mapping. In this survey, we review algorithmic paradigms --- search-based, cycle-based, transformation-based, and BDD-based --- as well as specific algorithms for reversible synthesis, both exact and heuristic. We conclude the survey by outlining key open challenges in synthesis of reversible and quantum logic, as well as most common misconceptions.Comment: 34 pages, 15 figures, 2 table

The Kazhdan-Lusztig conjecture for finite W-algebras

We study the representation theory of finite W-algebras. After introducing parabolic subalgebras to describe the structure of W-algebras, we define the Verma modules and give a conjecture for the Kac determinant. This allows us to find the completely degenerate representations of the finite W-algebras. To extract the irreducible representations we analyse the structure of singular and subsingular vectors, and find that for W-algebras, in general the maximal submodule of a Verma module is not generated by singular vectors only. Surprisingly, the role of the (sub)singular vectors can be encapsulated in terms of a `dual' analogue of the Kazhdan-Lusztig theorem for simple Lie algebras. These involve dual relative Kazhdan-Lusztig polynomials. We support our conjectures with some examples, and briefly discuss applications and the generalisation to infinite W-algebras.Comment: 11 page

Comparison of 32-site exact diagonalization results and ARPES spectral functions for the AFM insulator Sr2CuO2Cl2Sr_2CuO_2Cl_2

We explore the success of various versions of the one-band t-J model in explaining the full spectral functions found in angle-resolved photoemission spectra for the prototypical, quasi two-dimensional, tetragonal, antiferromagnetic insulator $Sr_2CuO_2Cl_2$. After presenting arguments justifying our extraction of $A(k,\omega)$ from the experimental data, we rely on exact-diagonalization results from studies of a square 32-site lattice, the largest cluster for which such information is presently available, to perform this comparison. Our work leads us to believe that (i) a one-band model that includes hopping out to third-nearest neighbours, as well three-site, spin-dependent hopping, can indeed explain not only the dispersion relation, but also the quasiparticle lifetimes -- only in the neighbourhood of $k = (\pi/2,0)$ do we find disagreement; (ii) an energy-dependent broadening function, $\Gamma (E) = \Gamma_0 + A E$, is important in accounting for the incoherent contributions to the spectral functions.Comment: 8 pages, Revtex

Pedestrians with Disabilities and Town and City Streets: From Shared to Inclusive Space?

This article highlights the importance of ensuring that accessibility and inclusion for people with disabilities, as required by the UN Convention on the Rights of Persons with Disabilities, is fully embedded in efforts to reduce the dominance of cars in city streets and promote more active modes of travel (including walking, wheeling and cycling) in line with global agendas. Drawing on emerging findings from the Inclusive Public Space research project, we present and critically reflect on types of difficulty associated with streets in which what is commonly known as a ‘shared space’ design operates, and those in which all or part of the available space is designated as primarily for pedestrian use. The data on which this analysis is based is qualitative, deriving from 83 semi-structured interviews about the experiences of our participants (a substantial majority of whom identified as having a disability) in two large UK cities and their wider metropolitan areas. The types of exclusionary experience described by our participants are organised into two broad overlapping categories – first, difficulties associated with navigating environments in which kerbs have been removed; and second, difficulties associated with interacting with vehicles (including bicycles) within and at the boundaries of shared or pedestrian spaces. Our findings are in line with those of previous projects that challenge and complicate claims that ‘shared space’ design, with its removal of kerbs and controlled crossings, enhances safety and mobility for all. Further, they demonstrate that many of the concerns associated with ‘shared space’ environments are also applicable to other types of street environment intended primarily for pedestrians. As well as highlighting and raising awareness of potential types of exclusion against which action should be taken, we draw attention to measures that could reduce the risk of such exclusionary barriers arising and persisting

On some nonlinear extensions of the angular momentum algebra

Deformations of the Lie algebras so(4), so(3,1), and e(3) that leave their so(3) subalgebra undeformed and preserve their coset structure are considered. It is shown that such deformed algebras are associative for any choice of the deformation parameters. Their Casimir operators are obtained and some of their unitary irreducible representations are constructed. For vanishing deformation, the latter go over into those of the corresponding Lie algebras that contain each of the so(3) unitary irreducible representations at most once. It is also proved that similar deformations of the Lie algebras su(3), sl(3,R), and of the semidirect sum of an abelian algebra t(5) and so(3) do not lead to associative algebras.Comment: 22 pages, plain TeX + preprint.sty, no figures, to appear in J.Phys.

Development of strategies for effective communication of food risks and benefits across Europe: Design and conceptual framework of the FoodRisC project

The FoodRisC project is funded under the Seventh Framework Programme (CORDIS FP7) of the European Commission; Grant agreement no.: 245124. Copyright @ 2011 Barnett et al.BACKGROUND: European consumers are faced with a myriad of food related risk and benefit information and it is regularly left up to the consumer to interpret these, often conflicting, pieces of information as a coherent message. This conflict is especially apparent in times of food crises and can have major public health implications. Scientific results and risk assessments cannot always be easily communicated into simple guidelines and advice that non-scientists like the public or the media can easily understand especially when there is conflicting, uncertain or complex information about a particular food or aspects thereof. The need for improved strategies and tools for communication about food risks and benefits is therefore paramount. The FoodRisC project ("Food Risk Communication - Perceptions and communication of food risks/benefits across Europe: development of effective communication strategies") aims to address this issue. The FoodRisC project will examine consumer perceptions and investigate how people acquire and use information in food domains in order to develop targeted strategies for food communication across Europe.METHODS/DESIGN: This project consists of 6 research work packages which, using qualitative and quantitative methodologies, are focused on development of a framework for investigating food risk/benefit issues across Europe, exploration of the role of new and traditional media in food communication and testing of the framework in order to develop evidence based communication strategies and tools. The main outcome of the FoodRisC project will be a toolkit to enable coherent communication of food risk/benefit messages in Europe. The toolkit will integrate theoretical models and new measurement paradigms as well as building on social marketing approaches around consumer segmentation. Use of the toolkit and guides will assist policy makers, food authorities and other end users in developing common approaches to communicating coherent messages to consumers in Europe.DISCUSSION: The FoodRisC project offers a unique approach to the investigation of food risk/benefit communication. The effective spread of food risk/benefit information will assist initiatives aimed at reducing the burden of food-related illness and disease, reducing the economic impact of food crises and ensuring that confidence in safe and nutritious food is fostered and maintained in Europe.This article is available through the Brunel Open Access Publishing Fund