K-classes of Brill-Noether loci and a determinantal formula

We prove a determinantal formula for the K-theory class of certain degeneracy loci, and apply it to compute the Euler characteristic of the structure sheaf of the Brill-Noether locus of linear series with special vanishing at marked points. When the Brill-Noether number $\rho$ is zero, we recover the Castelnuovo formula for the number of special linear series on a general curve; when $\rho=1$, we recover the formulas of Eisenbud-Harris, Pirola, and Chan-L\'opez-Pflueger-Teixidor for the arithmetic genus of a Brill-Noether curve of special divisors. Our degeneracy locus formula also specializes to new determinantal expressions for the double Grothendieck polynomials corresponding to 321-avoiding permutations, and gives double versions of the flagged skew Grothendieck polynomials recently introduced by Matsumura. Our result extends the formula of Billey-Jockusch-Stanley expressing Schubert polynomials for 321-avoiding permutations as generating functions for skew tableaux.Comment: 31 pages; v2: stronger Theorem C, and improved expositio

Researching a segmented market:reflections on telephone interviewing

Purpose The purpose of this paper was to review the effectiveness of telephone interviewing for capturing data and to consider in particular the challenges faced by telephone interviewers when capturing information about market segments. Design/methodology/approach The platform for this methodological critique was a market segment analysis commissioned by Sport Wales which involved a series of 85 telephone interviews completed during 2010. Two focus groups involving the six interviewers involved in the study were convened to reflect on the researchers’ experiences and the implications for business and management research. Findings There are three principal sets of findings. First, although telephone interviewing is generally a cost-effective data collection method, it is important to consider both the actual costs (i.e. time spent planning and conducting interviews) as well as the opportunity costs (i.e. missed appointments, “chasing participants”). Second, researchers need to be sensitised to and sensitive to the demographic characteristics of telephone interviewees (insofar as these are knowable) because responses are influenced by them. Third, the anonymity of telephone interviews may be more conducive for discussing sensitive issues than face-to-face interactions. Originality/value The present study adds to this modest body of literature on the implementation of telephone interviewing as a research technique of business and management. It provides valuable methodological background detail about the intricate, personal experiences of researchers undertaking this method “at a distance” and without visual cues, and makes explicit the challenges of telephone interviewing for the purposes of data capture

Distortions in farmer prices since the 1950s: South Africa in international perspective

For decades, earnings from farming in many low-income countries have been depressed by a pro-urban bias in own-country policies, as well as by governments of richer countries favoring their farmers with import barriers and subsidies. Both sets of policies reduce national and global economic growth. They also add to inequality and poverty in developing countries, since most of the worldÂ’s billion poorest people depend on farming for their livelihood. Over the past two decades numerous developing country governments have reduced their sectoral and trade policy distortions, while some high-income countries also have begun reforming their protectionist policies. Drawing on results from a new multi-country research project, this paper examines the extent of South AfricaÂ’s reforms relative to those of other temperate-zone Southern Hemisphere countries, of Northern Hemisphere rich countries, and of other developing countries. It concludes by pointing to the scope and prospects for further pro-poor policy reform at home and abroad.Distorted incentives, agricultural and trade policy reforms

Influence of strain and oxygen vacancies on the magnetoelectric properties of multiferroic bismuth ferrite

The dependencies on strain and oxygen vacancies of the ferroelectric polarization and the weak ferromagnetic magnetization in the multiferroic material bismuth ferrite, BiFeO_3, are investigated using first principles density functional theory calculations. The electric polarization is found to be rather independent of strain, in striking contrast to most conventional perovskite ferroelectrics. It is also not significantly affected by oxygen vacancies, or by the combined presence of strain and oxygen vacancies. The magnetization is also unaffected by strain, however the incorporation of oxygen vacancies can alter the magnetization slightly, and also leads to the formation of Fe^{2+}. These results are discussed in light of recent experiments on epitaxial films of BiFeO_3 which reported a strong thickness dependence of both magnetization and polarization.Comment: 9 pages, 3 figure

Using electronic patient-reported outcomes to promote quality of care and safety in the management of patients with end stage kidney disease requiring treatment with haemodialysis

Patients with Chronic Kidney Disease (CKD), particularly those with end-stage kidney disease (ESKD) undertaking haemodialysis (HD), often experience a high symptom burden and diminished health-related quality of life. Data on these constructs can be collected directly from patients and measured using electronic patient-reported outcomes (ePROs). Responses can be used at an individual level to facilitate optimal care and improve shared decision making; research from other clinical settings suggests ePROs use can improve clinician/patient communication, improve health related quality of life, reduce hospitalisations, and increase overall survival, while demonstrating cost effectiveness. At an aggregate level, these data can be used for audit and benchmarking to improve services. However, ePROs have not been implemented routinely and systematically in kidney care settings. The overall aim of this thesis was to explore and inform the evidence on how ePROs might be used to promote quality of care and safety in the management of patients with ESKD requiring treatment with HD. Firstly, a synthesis of current evidence on the use and implementation of PROs for patients with ESKD receiving HD was undertaken; identifying gaps in the evidence base and areas for investigation to deliver a roadmap for increasing the evidence base and introducing ePROs into mainstream HD clinical practice. Informed by these findings, a qualitative study was conducted, exploring the views, perceptions, and experiences of 22 patients receiving HD and 17 health care professionals (HCPs) in the HD multi-disciplinary team regarding the collection and use ePROs, in HD settings. This study highlighted the need to measure outcomes important to both patients and clinicians and supported the relevance of patient-reported outcomes included in HD-specific core outcome sets (COS). The study stressed the importance of building an empirical evidence base to support the use of ePROs and discussed key contextual implementation factors, including barriers and facilitators, to successful integration into clinical workflow. Leading on from this was a study to examine whether currently available patient-reported outcome measures (PROMs) used in HD adequately cover outcomes/domains recommended in HD-specific COS. A systematic search of published literature identified two HD-specific COS designed for use in HD research and routine clinical care and 46 validated PROMs currently being used in HD settings. Following assessment of COS coverage and measure characteristics, options for measure choice were outlined. Finally, to gain a deeper understanding of how ePROs might be successfully implemented, a mixed methods study was undertaken to comprehensively identify ePRO systems for CKD to explore system characteristics including methods of administration, levels of integration into existing workflow and electronic health records (EHR) and the reporting of ePROs to manage patient safety. Overall, 15 ePRO systems were identified allowing a comprehensive classification of core factors which contribute to successful implementation of ePROs in nephrology, including common facilitators and barriers. To conclude, this thesis describes the current and potential use of ePROs in CKD, with a focus on use in haemodialysis (HD) populations. It draws together a range of original research, including views on potential measures, existing and emerging ePRO systems and priority areas for future research to outline a roadmap to use ePROs to improve the quality of care delivered to patients with ESKD undergoing HD

Origin of ferroelectricity in the multiferroic barium fluorides BaMF4

We present a first principles study of the series of multiferroic barium fluorides with the composition BaMF4, where M is Mn, Fe, Co, or Ni. We discuss trends in the structural, electronic, and magnetic properties, and we show that the ferroelectricity in these systems results from the "freezing in" of a single unstable polar phonon mode. In contrast to the case of the standard perovskite ferroelectrics, this structural distortion is not accompanied by charge transfer between cations and anions. Thus, the ferroelectric instability in the multiferroic barium fluorides arises solely due to size effects and the special geometrical constraints of the underlying crystal structure.Comment: 8 pages, 6 figures, 3 table