Improving the A-Contrario computation of a fundamental matrix in computer vision

Laboratoire MAP5 (Mathématiques appliquées Paris 5), CNRS UMR8145 Université Paris V - Paris DescartesThe fundamental matrix is a two-view tensor playing a central role in Computer Vision geometry. We address its robust estimation given pairs of matched image features, affected by noise and outliers, which searches for a maximal subset of correct matches and the associated fundamental matrix. Overcoming the broadly used parametric RANSAC method, ORSA follows a probabilistic a contrario approach to look for the set of matches being least expected with respect to a uniform random distribution of image points. ORSA lacks performance when this assumption is clearly violated. We will propose an improvement of the ORSA method, based on its same a contrario framework and the use of a non-parametric estimate of the distribution of image features. The role and estimation of the fundamental matrix and the data SIFT matches will be carefully explained with examples. Our proposal performs significantly well for common scenarios of low inlier ratios and local feature concentrations

A global optimisation approach to range-restricted survey calibration

Survey calibration methods modify minimally unit-level sample weights to fit domain-level benchmark constraints (BC). This allows exploitation of auxiliary information, e.g. census totals, to improve the representativeness of sample data (addressing coverage limitations, non-response) and the quality of estimates of population parameters. Calibration methods may fail with samples presenting small/zero counts for some benchmark groups or when range restrictions (RR), such as positivity, are imposed to avoid unrealistic or extreme weights. User-defined modifications of BC/RR performed after encountering non-convergence allow little control on the solution, and penalization approaches modelling infeasibility may not guarantee convergence. Paradoxically, this has led to underuse in calibration of highly disaggregated information, when available. We present an always-convergent flexible two-step Global Optimisation (GO) survey calibration approach. The feasibility of the calibration problem is assessed, and automatically controlled minimum errors in BC or changes in RR are allowed to guarantee convergence in advance, while preserving the good properties of calibration estimators. Modelling alternatives under different scenarios, using various error/change and distance measures are formulated and discussed. The GO approach is validated by calibrating the weights of the 2012 Health Survey for England to a fine age-gender-region cross-tabulation (378 counts) from the 2011 Census in England and Wales

Trends in survival of older care home residents in England: a 10-year multi-cohort study

Increases in longevity combined with a policy emphasis on caring for older people in their own homes could have widened or narrowed the survival gap between care home and community-dwelling resident older people. Knowledge of pre-Covid-19 trends in this gap is needed to assess the longer-term impacts of the pandemic. We provide evidence for England on recent trends in 1, 2 and 3-year mortality amongst care home residents aged 65+ compared with similar community-dwelling residents. We use the Clinical Practice Research Datalink, a nationally representative primary care database. For each of the ten years from 2006 to 2015, care home and community-dwelling residents aged 65+ were identified and matched in the ratio 1:3, according to age, gender, area deprivation and region. Cox survival analyses were used to estimate mortality risks for care home residents in comparison with similar community-dwelling people, adjusting for age, gender, area deprivation and region. The study sample consisted of ten overlapping cohorts averaging 5,495 care home residents per cohort. Adjusted mortality risks increased over the study period for care home residents while decreasing slightly for matched community-dwelling residents. The relative risks (RRs) of mortality associated with care home residence were higher for younger ages and shorter follow-up periods, in all years. Over the decade, the RRs increased, most at younger ages and for shorter follow-up periods (e.g. for the age group 65–74 years, 1-year average RR increased by 61% from 5.4 to 8.8, while for those aged 85-94 years and over, 3-year RR increased by 22% from 1.3 to 1.6). Thus the survival gap between older care home and community-dwelling residents has been widening, especially at younger ages. In due course, it will be possible to establish to what extent the Covid-19 pandemic has resulted in further growth in this gap

Clinical characteristics, activity levels and mental health problems in children with long coronavirus disease: a survey of 510 children

Background: Whether long coronavirus disease pertains to children as well is not yet clear. Methods: The authors performed a survey in children suffering from persistent symptoms since initial infection. A total of 510 children infected between January 2020 and January 2021 were included. Results: Symptoms such as fatigue, headache, muscle and joint pain, rashes and heart palpitations and issues such as lack of concentration and short-term memory problems were particularly frequent and confirm previous observations, suggesting that they may characterize this condition. Conclusion: A better comprehension of long coronavirus disease is urgently needed

Transfer of congenital heart patients from paediatric to adult services in England

OBJECTIVE: This study assessed the transfer of patients from paediatric cardiac to adult congenital heart disease (ACHD) services in England and the factors impacting on this process. METHODS: This retrospective cohort study used a population-based linked data set (LAUNCHES QI data set: 'Linking Audit and National datasets in Congenital Heart Services for Quality Improvement') including all patients born between 1987 and 2000, recorded as having a congenital heart disease (CHD) procedure in childhood. Hospital Episode Statistics data identified transfer from paediatric to ACHD services between the ages of 16 and 22 years. RESULTS: Overall, 63.8% of a cohort of 10 298 patients transferred by their 22nd birthday. The estimated probability of transfer by age 22 was 96.5% (95% CI 95.3 to 97.7), 86.7% (95% CI 85.6 to 87.9) and 41.0% (95% CI 39.4 to 42.6) for severe, moderate and mild CHD, respectively. 166 patients (1.6%) died between 16 and 22 years; 42 of these (0.4%) died after age 16 but prior to transfer. Multivariable ORs in the moderate and severe CHD groups up to age 20 showed significantly lower likelihood of transfer among female patients (0.87, 95% CI 0.78 to 0.97), those with missing ethnicity data (0.31, 95% CI 0.18 to 0.52), those from deprived areas (0.84, 95% CI 0.72 to 0.98) and those with moderate (compared with severe) CHD (0.30, 95% CI 0.26 to 0.35). The odds of transfer were lower for the horizontal compared with the vertical care model (0.44, 95% CI 0.27 to 0.72). Patients who did not transfer had a lower probability of a further National Congenital Heart Disease Audit procedure between ages 20 and 30 compared with those who did transfer: 12.3% (95% CI 5.1 to 19.6) vs 32.5% (95% CI 28.7 to 36.3). CONCLUSIONS: Majority of patients with moderate or severe CHD in England transfer to adult services. Patients who do not transfer undergo fewer elective CHD procedures over the following decade

Arterial Switch for Transposition of the Great Arteries

Background Reports of long-term mortality and reintervention after transposition of the great arteries with intact ventricular septum treatment, although favorable, are mostly limited to single-center studies. Even less is known about hospital resource utilization (days at hospital) and the impact of treatment choices and timing on outcomes. Objectives The purpose of this study was to describe survival, reintervention and hospital resource utilization after arterial switch operation (ASO) in a national dataset. Methods Follow-up and life status data for all patients undergoing ASO between 2000 and 2017 in England and Wales were collected and explored using multivariable regressions and matching. Results A total of 1,772 patients were identified, with median ASO age of 9.5 days (IQR: 6.5-14.5 days). Mortality and cardiac reintervention at 10 years after ASO were 3.2% (95% CI: 2.5%-4.2%) and 10.7% (95% CI: 9.1%-12.2%), respectively. The median time spent in hospital during the ASO spell was 19 days (IQR: 14, 24). Over the first year after the ASO patients spent 7 days (IQR: 4-10 days) in hospital in total, decreasing to 1 outpatient day/year beyond the fifth year. In a subgroup with complete risk factor data (n = 652), ASO age, and balloon atrial septostomy (BAS) use were not associated with late mortality and reintervention, but cardiac or congenital comorbidities, low weight, and circulatory/renal support at ASO were. After matching for patient characteristics, BAS followed by ASO and ASO as first procedure, performed within the first 3 weeks of life, had comparable early and late outcomes, including hospital resource utilization. Conclusions Mortality and hospital resource utilization are low, while reintervention remains relatively frequent. Early ASO and individualized use of BAS allows for flexibility in treatment choices and a focus on at-risk patients

Interactions between state pension and long-term care reforms: an overview

In April 2016 major reforms to state pensions and long-term care will be implemented in Great Britain and England respectively. Their combined effects have received little attention despite interactions between the two systems. The long-term effects of both sets of reforms will depend on how details of the systems are set in the intervening years, and on how policies in other parts of the welfare system evolve. We will investigate the long-term impacts of alternative ways in which current pensions and long-term care financing reforms may evolve over the next 40 years to ensure that that there is widespread appreciation of the implications of any changes which may have significant long-term effects

Care and State Pension Reform - Interactions between state and pension long-term care reforms: a summary of findings

In April 2016 major reforms to state pensions were implemented in Great Britain. Reforms to the English long-term care financing system were also to be introduced in 2016 but have been postponed until 2020. The state pension reforms replace the existing two-tier state pension system with a single tier pension set just above the minimum income guaranteed through means-tested benefits. It affects only people reaching State Pension age from April 2016. The long-term care reforms introduce a cap on lifetime liability for care costs. To reach the cap, people will need to have eligible care needs for a considerable period, typically at least three years. The primary objective of the state pension reforms is to provide a clearer foundation for private pension saving and reduce reliance on means-tested benefits in retirement by setting the level of the new State Pension (nSP) above the level of the minimum income guaranteed by the means-tested benefit Pension Credit. The long-term care reforms introduce a lifetime limit on individual liability for care costs to provide protection against the risk that care costs could use up nearly all of an individual’s savings. The long-term effects of both sets of reforms will depend on how details of the systems are set in the intervening years, and in particular how components of the systems are adjusted each year – ‘uprated’ – for inflation. This report summarises the findings from a research project which aims to promote informed debate on how the reforms could evolve, highlighting the interactions between the two systems. Amongst other things, the study has analysed the impact of the reforms to 2030 under uprating assumptions consistent with current policy and under alternative uprating assumptions. A separate more detailed Technical Report of the analysis is available