Polca SARA - Full polarization, direction-dependent calibration and sparse imaging for radio interferometry

New generation of radio interferometers are envisaged to produce high quality, high dynamic range Stokes images of the observed sky from the corresponding under-sampled Fourier domain measurements. In practice, these measurements are contaminated by the instrumental and atmospheric effects that are well represented by Jones matrices, and are most often varying with observation direction and time. These effects, usually unknown, act as a limiting factor in achieving the required imaging performance and thus, their calibration is crucial. To address this issue, we develop a global algorithm, named Polca SARA, aiming to perform full polarization, direction-dependent calibration and sparse imaging by employing a non-convex optimization technique. In contrast with the existing approaches, the proposed method offers global convergence guarantees and flexibility to incorporate sophisticated priors to regularize the imaging as well as the calibration problem. Thus, we adapt a polarimetric imaging specific method, enforcing the physical polarization constraint along with a sparsity prior for the sought images. We perform extensive simulation studies of the proposed algorithm. While indicating the superior performance of polarization constraint based imaging, the obtained results also highlight the importance of calibrating for direction-dependent effects as well as for off-diagonal terms (denoting polarization leakage) in the associated Jones matrices, without inclusion of which the imaging quality deteriorates

The nature and role of empathy in public librarianship

This article presents two recent studies, an AHRC-funded exploration of the role of empathy in community librarianship (Study 1) and an investigation of the role of empathy in service to minority ethnic users (Study 2). Qualitative elements of each methodology are presented, namely a series of focus groups with frontline staff, interviews with senior managers and a research workshop (Study 1), and a case study investigation of a public library in the heart of a Chinese community (Study 2). Synthesizing the data of both studies, an analysis is conducted of the relationship between the cultural identities of library staff and their ability to empathize with the public. It is concluded that empathy plays a role in facilitating effective communication between staff and users, but that a distinction should be made between intuitive and cognitive empathy, in considering the potential of staff training to develop appropriate levels of emotional response to members of all communities

A framework model for a contextualized and integrated warfarin therapy case in a master of pharmacy program

© Copyright 2019 American Journal of Pharmaceutical Education.Objective. To develop and integrate a case study on warfarin into a clinical pharmacy workshop. Methods. A framework model was designed and used to create a case study on warfarin therapy. The case study was implemented in a third-year Master of Pharmacy course. Student feedback was obtained using an online questionnaire and two focus groups. Results. All students agreed that the case study successfully integrated the science of warfarin and concepts of pharmacy practice. The majority of students (94%) agreed that this approach helped them to understand the science of warfarin more than a traditional lecture would have. Students felt the time allocated to the workshop was too short. Conclusion. An integrated case study provides a learning environment that emphasizes the contextualization of chemistry and pharmacology into a clinical pharmacy setting.Peer reviewedFinal Published versio

Research

This chapter provides an overview of the research in librarianship and information science (hereafter LIS) carried out in the UK in the period 2011-2015, complementing the analogous British Librarianship and Information Work chapters by Nicolas for the periods 1991-2000 and 2001-2005 and by Sen and Willett for the period 2006-2010. More specifically, we consider first the funding environment for LIS research in the UK, and then the process and outcome of REF2014, a nationwide evaluation of the quality of research conducted by UK universities. The next, and largest, section discusses the range of LIS research being conducted in the UK as reflected in both the academic and the professional literatures, the latter including a brief discussion of the perceived value of different media to the research process, and the chapter concludes by summarising important characteristics, both positive and negative, of the current state of LIS research in the UK

Reader development

Reader development, with adult readers in particular, has experienced a dramatic growth in relatively recent years. This chapter explores this growth, in terms of its impact on library service delivery and policy, and in the context of its more social benefits. Themes frequently used in definitions of reader development are considered, such as intervention, cultural change, reader-centred and social inclusion. A number of frequently cross-sectoral initiatives are presented in order to exemplify the various facets of these definitions. The chapter ends with a consideration of the future of reader development

'We are here because you were there': minority ethnic genre fiction in UK public libraries.

This paper presents findings of ongoing doctoral research into the reading of, and engagement with, minority ethnic genre fiction in public libraries, with a particular focus on Black British and British Asian authors. The research context is first briefly summarised, looking at the nature of minority genre fiction, and at public library provision and readership of materials for ethnically diverse communities. An empirical study is then presented, for which a general survey was conducted of the reading habits and attitudes of library users in the East Midlands region of England. The large sample population of 1,047 public library users enabled both qualitative and quantitative analyses, considering readers’ preferred location for selecting books, their usual reading choices, material that they would not consider reading, and any factors affecting their choice. Finally, a brief comparison is made of libraries of different types, in terms of community, ethnicity or class. The findings indicate that certain respondents appeared to have an increased openness to read from a wide range of genres, even an increased reading confidence as a result of reading books written by minority ethnic authors. It is concluded that promotional activity can play a role not only in offering wider reading choices but also, potentially, in reducing fear and prejudice and celebrating cultural diversity

Alginate hydrogel has a negative impact on in vitro collagen 1 deposition by fibroblasts

Hydrogels have been widely investigated as 3D culture substrates because of their reported structural similarity to the extracellular matrix (ECM). Limited ECM deposition, however, occurs within these materials, so the resulting “tissues” bear little resemblance to those found in the body. Here matrix deposition by fibroblasts encapsulated within a calcium alginate (Ca-alg) hydrogel was investigated. Although the cells transcribed mRNA for coll Iα over a period of 3 weeks, very little collagen protein deposition was observed within the gel by histology or immunohistochemistry (IHC). Although molecular diffusion demonstrated charge dependency, this did not prevent the flux of both positively and negative charged amino acids through the gel, suggesting that the absence of ECM could not be attributed to substrate limitation. The flux of protein, however, was charge-dependent as proteins with a net negative charge passed quickly through the Ca-alg into the medium. The minimal collagen deposition within the Ca-alg was attributed to a combination of rapid movement of negatively charged procollagen through the gel and steric hindrance of fibril formation

Scanning Quantum Decoherence Microscopy

The use of qubits as sensitive magnetometers has been studied theoretically and recent demonstrated experimentally. In this paper we propose a generalisation of this concept, where a scanning two-state quantum system is used to probe the subtle effects of decoherence (as well as its surrounding electromagnetic environment). Mapping both the Hamiltonian and decoherence properties of a qubit simultaneously, provides a unique image of the magnetic (or electric) field properties at the nanoscale. The resulting images are sensitive to the temporal as well as spatial variation in the fields created by the sample. As an example we theoretically study two applications of this technology; one from condensed matter physics, the other biophysics. The individual components required to realise the simplest version of this device (characterisation and measurement of qubits, nanoscale positioning) have already been demonstrated experimentally.Comment: 11 pages, 5 low quality (but arXiv friendly) image