Semi-classical analysis of non self-adjoint transfer matrices in statistical mechanics. I

We propose a way to study one-dimensional statistical mechanics models with complex-valued action using transfer operators. The argument consists of two steps. First, the contour of integration is deformed so that the associated transfer operator is a perturbation of a normal one. Then the transfer operator is studied using methods of semi-classical analysis. In this paper we concentrate on the second step, the main technical result being a semi-classical estimate for powers of an integral operator which is approximately normal.Comment: 28 pp, improved the presentatio

Towards high-resolution astronomical imaging

This paper is a report from a recent meeting on "the Future of high-resolution imaging in the visible and infrared", reviewing the astronomical drivers for development and the technological advances that might boost performance. Each of the authors listed contributed a section themselves.Comment: 6 pages, 7 figures, 11 contributors, Accepted for publication in Astronomy & Geophysics of the RAS, June 2019 issu

Protocol for the development and analysis of the Oxford and Reading Cognitive Comorbidity, Frailty and Ageing Research Database - Electronic Patient Records (ORCHARD-EPR)

Background Hospital electronic patient records (EPRs) offer the opportunity to exploit large-scale routinely acquired data at relatively low cost and without selection. EPRs provide considerably richer data, and in real-time, than retrospective administrative data sets in which clinical complexity is often poorly captured. With population ageing, a wide range of hospital specialties now manage older people with multimorbidity, frailty and associated poor outcomes. We, therefore, set-up the Oxford and Reading Cognitive Comorbidity, Frailty and Ageing Research Database-Electronic Patient Records (ORCHARD-EPR) to facilitate clinically meaningful research in older hospital patients, including algorithm development, and to aid medical decision-making, implementation of guidelines, and inform policy. Methods and analysis ORCHARD-EPR uses routinely acquired individual patient data on all patients aged ≥65 years with unplanned admission or Same Day Emergency Care unit attendance at four acute general hospitals serving a population of >800 000 (Oxfordshire, UK) with planned extension to the neighbouring Berkshire regional hospitals (>1 000 000). Data fields include diagnosis, comorbidities, nursing risk assessments, frailty, observations, illness acuity, laboratory tests and brain scan images. Importantly, ORCHARD-EPR contains the results from mandatory hospital-wide cognitive screening (≥70 years) comprising the 10-point Abbreviated-Mental-Test and dementia and delirium diagnosis (Confusion Assessment Method—CAM). Outcomes include length of stay, delayed transfers of care, discharge destination, readmissions and death. The rich multimodal data are further enhanced by linkage to secondary care electronic mental health records. Selection of appropriate subgroups or linkage to existing cohorts allows disease-specific studies. Over 200 000 patient episodes are included to date with data collection ongoing of which 129 248 are admissions with a length of stay ≥1 day in 64 641 unique patients. Ethics and dissemination ORCHARD-EPR is approved by the South Central Oxford C Research Ethics Committee (ref: 23/SC/0258). Results will be widely disseminated through peer-reviewed publications and presentations at conferences, and regional meetings to improve hospital data quality and clinical services

Associations between maternal psychological distress and mother-infant bonding: a systematic review and meta-analysis

Purpose: Maternal psychological distress and mother-infant bonding problems each predict poorer offspring outcomes. They are also related to each other, yet the extensive literature reporting their association has not been meta-analysed. Methods: We searched MEDLINE, PsycINFO, CINAHL, Embase, ProQuest DTG, and OATD for English-language peer-reviewed and grey literature reporting an association between mother-infant bonding, and multiple indicators of maternal psychological distress. Results: We included 133 studies representing 118 samples; 99 samples (110,968 mothers) were eligible for meta-analysis. Results showed concurrent associations across a range of timepoints during the first year postpartum, between bonding problems and depression (r = .27 [95% CI 0.20, 0.35] to r = .47 [95% CI 0.41, 0.53]), anxiety (r = .27 [95% CI 0.24, 0.31] to r = .39 [95% CI 0.15, 0.59]), and stress (r = .46 [95% CI 0.40, 0.52]). Associations between antenatal distress and subsequent postpartum bonding problems were mostly weaker and with wider confidence intervals: depression (r = .20 [95% CI 0.14, 0.50] to r = .25 [95% CI 0.64, 0.85]), anxiety (r = .16 [95% CI 0.10, 0.22]), and stress (r = .15 [95% CI − 0.67, 0.80]). Pre-conception depression and anxiety were associated with postpartum bonding problems (r = − 0.17 [95% CI − 0.22, − 0.11]). Conclusion: Maternal psychological distress is associated with postpartum mother-infant bonding problems. Co-occurrence of psychological distress and bonding problems is common, but should not be assumed. There may be benefit in augmenting existing perinatal screening programs with well-validated mother-infant bonding measures

A multi-instrument and multi-wavelength high angular resolution study of MWC614: quantum heated particles inside the disk cavity

High angular resolution observations of young stellar objects are required to study the inner astronomical units of protoplanetary disks in which the majority of planets form. As they evolve, gaps open up in the inner disk regions and the disks are fully dispersed within ~10 Myrs. MWC 614 is a pre-transitional object with a ~10au radius gap. We present a set of high angular resolution observations of this object including SPHERE/ZIMPOL polarimetric and coronagraphic images in the visible, KECK/NIRC2 near-infrared aperture masking observations and VLTI (AMBER, MIDI, and PIONIER) and CHARA (CLASSIC and CLIMB) long-baseline interferometry at infrared wavelengths. We find that all the observations are compatible with an inclined disk (i ~55deg at a position angle of ~20-30deg). The mid-infrared dataset confirms the disk inner rim to be at 12.3+/-0.4 au from the central star. We determined an upper mass limit of 0.34 Msun for a companion inside the cavity. Within the cavity, the near-infrared emission, usually associated with the dust sublimation region, is unusually extended (~10 au, 30 times larger than the theoretical sublimation radius) and indicates a high dust temperature (T~1800 K). As a possible result of companion-induced dust segregation, quantum heated dust grains could explain the extended near-infrared emission with this high temperature. Our observations confirm the peculiar state of this object where the inner disk has already been accreted onto the star exposing small particles inside the cavity to direct stellar radiation.Comment: 24 pages. Published in Ap

Neuromuscular electrical stimulation as an adjunct to standard care in improving walking distances in intermittent claudication patients: the NESIC RCT

Background Peripheral arterial disease is common and associated with increased cardiovascular morbidity and mortality. While patients with peripheral arterial disease are known to benefit from supervised exercise therapy, it is not always available. Neuromuscular electrical stimulation devices may offer a similar benefit. A randomised controlled trial was required to ascertain whether such devices can benefit patients who receive supervised exercise therapy and those who do not. Objective(s) The primary objective was to assess the mean difference in absolute walking distance at 3 months in intermittent claudication patients receiving either a neuromuscular electrical stimulation device and local standard care (intervention), or local standard care alone (control). Design A pragmatic, multicentre, randomised controlled trial stratified by centre. Setting Secondary-care National Health Service hospitals in the United Kingdom. Participants Patients aged ≥18 years, with a diagnosis of intermittent claudication according to the Edinburgh Claudication Questionnaire and ankle–brachial pressure index (or stress test), without contraindications to neuromuscular electrical stimulation were deemed eligible to partake. Interventions Participants were randomised 1 : 1 to either local standard care or local standard care and neuromuscular electrical stimulation. Due to the nature of the intervention, it was unfeasible to blind the research nurse or participant to the study allocation. Main outcome measures The primary outcome measure was absolute walking distance measured by treadmill testing at 3 months. Secondary outcomes included change in initial claudication distance, quality of life, compliance with interventions and haemodynamic assessments. Results Two hundred patients underwent randomisation, with 160 patients having analysable primary outcome data for the intention-to-treat analysis intervention (n = 80); control (n = 80). As the data were right-censored, a Tobit regression model was used to analyse the primary outcome, utilising the square root of the absolute walking distance to accommodate the skewed data. However, as this made the data difficult to interpret, a Tobit regression model using raw absolute walking distance data was used as well. Neuromuscular electrical stimulation improved the difference in absolute walking distance at 3 months but this was not statistically significant (square root of absolute walking distance: 0.835 units, 95% confidence interval −0.67 to 2.34 units; p = 0.28/absolute walking distance raw data: 27.18 m, 95% confidence interval −26.92 to 81.28 m; p = 0.323). Supervised exercise therapy participants showed a markedly improved absolute walking distance compared with patients receiving best medical therapy only at 3 months (square root of absolute walking distance: 3.295 units 95% confidence interval 1.77 to 4.82; p < 0.001/absolute walking distance raw data: 121.71 m, 95% confidence interval 67.32 to 176.10; p ≤ 0.001). Neuromuscular electrical stimulation significantly improved absolute walking distance at 3 months for mild claudicants (square root of absolute walking distance: 2.877 units, 95% confidence interval 0.51 to 5.25; p = 0.019/absolute walking distance raw data: 120.55 m, 95% confidence interval 16.03 to 225.06; p = 0.03) compared to the control arm. This was an unplanned (post hoc) analysis. There were no clear differences in mechanistic measurements between the two treatment groups over the follow-up period. Serious adverse events were evenly reported between the two groups; all being classified as either not related or unlikely to be related to the study device. Limitations Absolute walking distance was used as the primary outcome measure; there was a large range of baseline distances in both groups with right-skewed distribution. We did not stratify by baseline absolute walking distance for the primary outcome analysis. Additionally, only 160 patients had analysable primary outcome data due to missing treadmill data. Conclusions Supervised exercise therapy is an effective treatment for intermittent claudication. Neuromuscular electrical stimulation appears to be beneficial as an adjunct to supervised exercise therapy and on its own in mild claudicants. Future work Further studies are needed to confirm the effectiveness of neuromuscular electrical stimulation in combination with supervised exercise therapy, and in mild to moderate claudicants in a larger sample size. Study registration This trial is registered as ISRCTN18242823. Funding This project was funded by the Efficacy and Mechanism Evaluation (EME) Programme, a Medical Research Council (MRC) and National Institute for Health and Care Research (NIHR) partnership (project number 15/180/68). This will be published in full in Efficacy and Mechanism Evaluation; Vol. 10, No. 2. See the NIHR Journals Library website for further project information. Infrastructure support for this research was provided by the NIHR Imperial Biomedical Research Centre (BRC) (with others, e.g. NIHR Imperial CRF, Imperial College ECMC, NIHR Imperial PSTRC, NIHR London MIC, etc.)

Spin–orbit alignment of the β pictoris planetary system

A crucial diagnostic that can tell us about processes involved in the formation and dynamical evolution of planetary systems is the angle between the rotation axis of a star and a planet's orbital angular momentum vector ("spin-orbit" alignment or "obliquity"). Here we present the first spin-orbit alignment measurement for a wide-separation exoplanetary system, namely on the directly imaged planet β Pictoris b. We use VLTI/GRAVITY spectro-interferometry with an astrometric accuracy of 1 μas (microarcsecond) in the Brγ photospheric absorption line to measure the photocenter displacement associated with the stellar rotation. Taking inclination constraints from astroseismology into account, we constrain the three-dimensional orientation of the stellar spin axis and find that β Pic b orbits its host star on a prograde orbit. The angular momentum vectors of the stellar photosphere, the planet, and the outer debris disk are well aligned with mutual inclinations ≤3° ± 5°, which indicates that β Pic b formed in a system without significant primordial misalignments. Our results demonstrate the potential of infrared interferometry to measure the spin-orbit alignment for wide-separation planetary systems, probing a highly complementary regime to the parameter space accessible with the Rossiter-McLaughlin effect. If the low obliquity is confirmed by measurements on a larger sample of wide-separation planets, it would lend support to theories that explain the obliquity in Hot Jupiter systems with dynamical scattering and the Kozai-Lidov mechanism