977 research outputs found
Weak convergence to extremal processes and record events for non-uniformly hyperbolic dynamical systems
This is the author accepted manuscript. The final version is available from CUP via the DOI in this record.For a measure-preserving dynamical system (X , f, µ), we consider the time
series of maxima Mn = max{X1, . . . , Xn} associated to the process Xn = φ( f
n−1
(x))
generated by the dynamical system for some observable φ : X → R. Using a pointprocess
approach we establish weak convergence of the process Yn(t) = an(M[nt] − bn)
to an extremal process Y (t) for suitable scaling constants an, bn ∈ R. Convergence here
takes place in the Skorokhod space D(0, ∞) with the J1 topology. We also establish
distributional results for the record times and record values of the corresponding maxima
process.This research was partially supported by the London Mathematics Society (Scheme 4, no. 41126), and both authors thank the Erwin Schrodigner Institute (ESI) in Vienna where part of this work was carried out. MH wishes to thank the Department of Mathematics, University of Houston for hospitality and financial support, and MT thanks Exeter University for their hospitality and support
Psychologies of Ageing: Research, policy and practice
A frequent concern of older people and of those who work with older people is that research is often divorced from reality and does not inform everyday practice. For many years, psychology and related disciplines have investigated the social and psychological aspects of ageing from different perspectives. However, the contemporary challenges faced by older people and their carers remain substantial. There is a need to better connect research with policy and practice designed to improve the quality of life of older people. The aim of this special issue is to provide a forum for researchers, policy makers and practitioners to discuss particular initiatives and topics pertinent to people as they age. It is through this dialogue that researchers can gain further insight into the everyday issues faced by older people, and can become more aware of particular challenges faced in developing and implementing changes in policy and practice
The Giza Pyramid : learning from this megaproject
Purpose: This paper demonstrates the contemporary relevance of the management of the Great Pyramid of Giza project.
Design/methodology/approach: The paper uses evidence from the literature from many disciplines concerning both the objectives and construction of the pyramid. It relates this to recent discussion concerned with the issues faced in megaproject management which are core to discussion of success and failure.
Findings: The analysis shows the significance of the "break-fix model" of megaproject management and how having a sequence of megaprojects builds management through a learning process. It demonstrates the significance of innovation arising from the experience of previous projects in solving major technical challenges and illustrates the importance of the organisation and ethical management of a substantial workforce.
Research & practical limitations/implications: There is very limited reliable documentary evidence from the time of the construction of Giza (c 2560 BCE). Many sources concerning ancient Egypt are still widely contested. However, the use of research from a combination of disciplines demonstrates the relevance of the project and the importance of
learning from history to contemporary project management.
Originality/value:
We believe this is the first paper to analyse the Giza pyramid project from a project management
perspective. This was arguably the most significant construction project of ancient history, and the
paper explains the lessons which can be learnt which are very significant to today’s megaprojects.
Keywords: Project management history, megaproject, case study, “break-fix model" of megaproject management, Giza pyramid project
Pre-dialysis clinic attendance improves quality of life among hemodialysis patients
BACKGROUND: Although previous research has demonstrated that referral to pre-dialysis clinics is associated with favourable objective outcomes, the benefit of a pre-dialysis clinic from the perspective of patient-perceived subjective outcomes, such as quality of life (QOL), is less well defined. METHODS: A retrospective incident cohort study was conducted to determine if pre-dialysis clinic attendance was a predictor of better QOL scores measured within the first six months of hemodialysis (HD) initiation. Inclusion criteria were HD initiation from January 1 1998 to January 1 2000, diagnosis of chronic renal failure, and completion of the QOL questionnaire within six months of HD initiation. Patients receiving HD for less than four weeks were excluded. An incident cohort of 120 dialysis patients was identified, including 74 patients who attended at least one pre-dialysis clinic and 46 patients who did not. QOL was measured using the SF 36-Item Health Survey. Independent variables included age, sex, diabetes, pre-dialysis clinic attendance and length of attendance, history of ischemic heart disease, stroke, peripheral vascular disease, heart failure, malignancy, and chronic lung disease, residual creatinine clearance at dialysis initiation, and kt/v, albumin and hemoglobin at the time of QOL assessment. Bivariate and multivariate linear regression analyses were used to identify predictors of QOL scores. RESULTS: Multivariate analysis suggested that pre-dialysis clinic attendance was an independent predictor of higher QOL scores in four of eight health domains (physical function, p < 0.01; emotional role limitation, p = 0.01; social function, p = 0.01; and general health, p = 0.03), even after statistical adjustment for age, sex, residual renal function, kt/v, albumin, and co-morbid disease. Pre-dialysis clinic attendance was also an independent predictor of the physical component summary score (p = 0.03). CONCLUSIONS: We conclude that pre-dialysis clinic attendance favourably influences patient-perceived quality of life within six months of dialysis initiation
Jahn-Teller effects in initial and final states: high-resolution X-ray absorption, photoelectron and Auger spectroscopy of allene
Carbon K-edge resonant Auger spectra of gas-phase allene following excitation of the pre-edge 1s → π* transitions are presented and analysed with the support of EOM-CCSD/cc-pVTZ calculations. X-Ray absorption (XAS), X-ray photoelectron (XPS), valence band and non-resonant Auger spectra are also reanalysed with a series of computational approaches. The results presented demonstrate the importance of including nuclear ensemble effects for simulating X-ray observables and as an effective strategy for capturing Jahn-Teller effects in spectra
Detection of Exocometary CO within the 440 Myr Old Fomalhaut Belt: A Similar CO+CO 2 Ice Abundance in Exocomets and Solar System Comets
Recent Atacama Large Millimeter/submillimeter Array observations present mounting evidence for the presence of exocometary gas released within Kuiper Belt analogs around nearby main-sequence stars. This represents a unique opportunity to study their ice reservoir at the younger ages when volatile delivery to planets is most likely to occur. We here present the detection of CO J = 2-1 emission colocated with dust emission from the cometary belt in the 440 Myr old Fomalhaut system. Through spectrospatial filtering, we achieve a 5.4σ detection and determine that the ring's sky-projected rotation axis matches that of the star. The CO mass derived ((0.65\mbox{--}42)\times {10}^{-7}\,{M}_{\oplus }) is the lowest of any circumstellar disk detected to date and must be of exocometary origin. Using a steady-state model, we estimate the CO+CO2 mass fraction of exocomets around Fomalhaut to be between 4.6% and 76%, consistent with solar system comets and the two other belts known to host exocometary gas. This is the first indication of a similarity in cometary compositions across planetary systems that may be linked to their formation scenario and is consistent with direct interstellar medium inheritance. In addition, we find tentative evidence that % of the detected flux originates from a region near the eccentric belt's pericenter. If confirmed, the latter may be explained through a recent impact event or CO pericenter glow due to exocometary release within a steady-state collisional cascade. In the latter scenario, we show how the azimuthal dependence of the CO release rate leads to asymmetries in gas observations of eccentric exocometary belts
A Complete ALMA Map of the Fomalhaut Debris Disk
© 2017. The American Astronomical Society. All rights reserved. We present ALMA mosaic observations at 1.3 mm (223 GHz) of the Fomalhaut system with a sensitivity of 14 μJy/beam. These observations provide the first millimeter map of the continuum dust emission from the complete outer debris disk with uniform sensitivity, enabling the first conclusive detection of apocenter glow. We adopt an MCMC modeling approach that accounts for the eccentric orbital parameters of a collection of particles within the disk. The outer belt is radially confined with an inner edge of 136.3 ± 0.9 au and width of 13.5 ± 1.8 au. We determine a best-fit eccentricity of 0.12 ± 0.01. Assuming a size distribution power-law index of q = 3.46 ± 0.09, we constrain the dust absorptivity power-law index β to be 0.9 < β < 1.5. The geometry of the disk is robustly constrained with inclination 65.°6 ± 0.°3, position angle 337.°9 ± 0.°3, and argument of periastron 22.°5 ± 4.°3. Our observations do not confirm any of the azimuthal features found in previous imaging studies of the disk with Hubble Space Telescope, SCUBA, and ALMA. However, we cannot rule out structures ≤10 au in size or that only affect smaller grains. The central star is clearly detected with a flux density of 0.75 ± 0.02 mJy, significantly lower than predicted by current photospheric models. We discuss the implications of these observations for the directly imaged Fomalhaut b and the inner dust belt detected at infrared wavelengths
Be SMART:examining the experience of implementing the NHS Health Check in UK primary care
Background: The NHS Health Check was designed by UK Department of Health to address increased prevalence of cardiovascular disease by identifying risk levels and facilitating behaviour change. It constituted biomedical testing, personalised advice and lifestyle support. The objective of the study was to explore Health Care Professionals' (HCPs) and patients' experiences of delivering and receiving the NHS Health Check in an inner-city region of England. Methods: Patients and HCPs in primary care were interviewed using semi-structured schedules. Data were analysed using Thematic Analysis. Results: Four themes were identified. Firstly, Health Check as a test of 'roadworthiness' for people. The roadworthiness metaphor resonated with some patients but it signified a passive stance toward illness. Some patients described the check as useful in the theme, Health check as revelatory. HCPs found visual aids demonstrating levels of salt/fat/sugar in everyday foods and a 'traffic light' tape measure helpful in communicating such 'revelations' with patients. Being SMART and following the protocolrevealed that few HCPs used SMART goals and few patients spoke of them. HCPs require training to understand their rationale compared with traditional advice-giving. The need for further follow-up revealed disparity in follow-ups and patients were not systematically monitored over time. Conclusions: HCPs' training needs to include the use and evidence of the effectiveness of SMART goals in changing health behaviours. The significance of fidelity to protocol needs to be communicated to HCPs and commissioners to ensure consistency. Monitoring and measurement of follow-up, e.g., tracking of referrals, need to be resourced to provide evidence of the success of the NHS Health Check in terms of healthier lifestyles and reduced CVD risk
- …