A sharp estimate for the first Robin-Laplacian eigenvalue with negative boundary parameter

In this paper we prove that the ball maximizes the first eigenvalue of the Robin Laplacian operator with negative boundary parameter, among all convex sets of \mathbb{R}^n with prescribed perimeter. The key of the proof is a dearrangement procedure of the first eigenfunction of the ball on the level sets of the distance function to the boundary of the convex set, which controls the boundary and the volume energies of the Rayleigh quotient

Patients with Diabetic Nephropathy in Established Renal Failure: Demographics, Survival and Biochemical Variables (Chapter 16)

Diabetic nephropathy is now the most common renal disease leading to renal replacement therapy in developed countries1,2,3,4. Within the UK, the number of DN patients accepted for RRT rose steadily in the 1990s5 especially in the African–Caribbean and South Asian populations3,4,5,6. This may be related to the increased prevalence of Type 2 diabetes in the general population, the ageing population and the liberalisation of attitudes to acceptance for RRT5,7. The overall rise has slowed in the last 4 years8 . DN patients starting RRT are likely to have more co-morbidity than other patients, in particular cardiovascular disease, and consequently worse survival on RRT9,10,11. In recent years there has been some reduction in the high mortality of such patients, so the prevalence of diabetic nephropathy patients on RRT (currently lower than the percentage of incident patients, see Chapter 3) might increase12,13. The National Service Frameworks for Diabetes14 and for Renal Services15 have highlighted the importance of the primary prevention of DN in diabetic patients by early detection and aggressive management of hypertension, glucose control and cardiovascular risk factors and of the timely referral (recommendation >1 yr before RRT) of those with progressive renal disease in order to plan for RRT. 251 There is a key policy drive to reduce health inequalities in England16. In the UK there is evidence that diabetic patients in more socially deprived areas have higher all cause mortality even after adjustment for smoking and blood pressure9 , and lower rates of attendance at GP and hospital clinics17. The UK Renal Registry 2003 Report highlighted the possible role of social deprivation in the context of DN. This chapter examines the characteristics of patients developing established renal failure from DN, their access to modalities of treatment and their survival on RRT relative to other incident patients. It also includes data on quality of care (HbA1c, cholesterol and blood pressure). These analyses were undertaken before individual patient data from the Scottish Registry became available and therefore only includes England and Wales

Is intergenerational social mobility related to the type and amount of physical activity in mid-adulthood? Results from the 1946 British birth cohort study.

PURPOSE: Greater levels of leisure-time or moderate-vigorous physical activity have consistently been found in those with greater socioeconomic position (SEP). Less is known about the effects of intergenerational social mobility. METHODS: We examined the influence of SEP and social mobility on mid-adulthood physical activity in the Medical Research Council National Survey of Health and Development. Two sub-domains of SEP were used: occupational class and educational attainment. Latent classes for walking, cycling, and leisure-time physical activity (LTPA) were used, plus sedentary behavior at age 36. Associations between types of physical activity and SEP were examined with the use of logistic or multinomial logistic regression. RESULTS: Being a manual worker oneself or having a father who was a manual worker was, relative to nonmanual work, associated with lower levels of sedentary behavior and greater walking activity, but also with lower LTPA. Compared with those who remained in a manual occupational class, upward occupational mobility was associated with more sedentary behavior, less walking, and increased LTPA. Associations with downward mobility were in the opposite directions. Similar results were obtained for educational attainment. CONCLUSIONS: This study found clear evidence of social differences in physical activity. Persistently high SEP and upward social mobility were associated with greater levels of LTPA but also increased sedentary behavior and less walking

Acute kidney injury in stable COPD and at exacerbation.

BACKGROUND: While acute kidney injury (AKI) alone is associated with increased mortality, the incidence of hospital admission with AKI among stable and exacerbating COPD patients and the effect of concurrent AKI at COPD exacerbation on mortality is not known. METHODS: A total of 189,561 individuals with COPD were identified from the Clinical Practice Research Datalink. Using Poisson and logistic regressions, we explored which factors predicted admission for AKI (identified in Hospital Episode Statistics) in this COPD cohort and concomitant AKI at a hospitalization for COPD exacerbation. Using survival analysis, we investigated the effect of concurrent AKI at exacerbation on mortality (n=36,107) and identified confounding factors. RESULTS: The incidence of AKI in the total COPD cohort was 128/100,000 person-years. The prevalence of concomitant AKI at exacerbation was 1.9%, and the mortality rate in patients with AKI at exacerbation was 521/1,000 person-years. Male sex, older age, and lower glomerular filtration rate predicted higher risk of AKI or death. There was a 1.80 fold (95% confidence interval: 1.61, 2.03) increase in adjusted mortality within the first 6 months post COPD exacerbation in patients suffering from AKI and COPD exacerbation compared to those who were AKI free. CONCLUSION: In comparison to previous studies on general populations and hospitalizations, the incidence and prevalence of AKI is relatively high in COPD patients. Coexisting AKI at exacerbation is prognostic of poor outcome

Polymorphisms in ARMS2/HTRA1 and complement genes and age-related macular degeneration in India: findings from the INDEYE study.

PURPOSE: Association between genetic variants in complement factor H (CFH), factor B (CFB), component 2 (C2), and in the ARMS2/HTRA1 region with age-related macular degeneration (AMD) comes mainly from studies of European ancestry and case-control studies of late-stage disease. We investigated associations of both early and late AMD with these variants in a population-based study of people aged 60 years and older in India. METHODS: Fundus images were graded using the Wisconsin Age-Related Maculopathy Grading System and participants assigned to one of four mutually exclusive stages based on the worse affected eye (0 = no AMD, 1-3 = early AMD, 4 = late AMD). Multinomial logistic regression was used to derive risk ratios (RR) accounting for sampling method and adjusting for age, sex, and study center. RESULTS: Of 3569 participants, 53.2% had no signs of amd, 45.6% had features of early amd, and 1.2% had late amd. CFH (RS1061170), C2 (RS547154), OR CFB (RS438999) was not associated with early or late AMD. In the ARMS2 locus, RS10490924 was associated with both early (adjusted RR 1.22, 95% confidence interval [CI]: 1.13-1.33, P < 0.0001) and late AMD (adjusted RR 1.81, 95% CI: 1.15-2.86; P = 0.01); rs2672598 was associated only with early AMD (adjusted RR 1.12, 95% CI: 1.02-1.23; P = 0.02); rs10490923 was not associated with early or late AMD. CONCLUSIONS: Two variants in ARMS2/HTRA1 were associated with increased risk of early AMD, and for one of these, the increased risk was also evident for late AMD. The study provides new insights into the role of these variants in early stages of AMD in India

Severe mental illness and chronic kidney disease: a cross-sectional study in the United Kingdom

OBJECTIVE: We investigated the burden of chronic kidney disease (CKD) among patients with severe mental illness (SMI). METHODS: We identified patients with SMI among all those aged 25–74 registered in the UK Clinical Practice Research Datalink as on March 31, 2014. We compared the prevalence of CKD (two measurements of estimated glomerular filtration rate <60 mL/min/1.73 m2 for ≥3 months) and renal replacement therapy between patients with and without SMI. For patients with and without a history of lithium prescription separately, we used logistic regression to examine the association between SMI and CKD, adjusting for demographics, lifestyle characteristics, and known CKD risk factors. RESULTS: The CKD prevalence was 14.6% among patients with SMI and a history of lithium prescription (n = 4,295), 3.3% among patients with SMI and no history of lithium prescription (n = 24,101), and 2.1% among patients without SMI (n = 2,387,988; P < 0.001). The prevalence of renal replacement therapy was 0.23%, 0.15%, and 0.11%, respectively (P = 0.012). Compared to patients without SMI, the fully adjusted odds ratio for CKD was 6.49 (95% CI 5.84–7.21) for patients with SMI and a history of lithium prescription and 1.45 (95% CI 1.34–1.58) for patients with SMI and no history of lithium prescription. The higher prevalence of CKD in patients with SMI may, in part, be explained by more frequent blood testing as compared to the general population. CONCLUSION: CKD is identified more commonly among patients with SMI than in the general population

Gravitational Lorentz Force and the Description of the Gravitational Interaction

In the context of a gauge theory for the translation group, we have obtained, for a spinless particle, a gravitational analog of the Lorentz force. Then, we have shown that this force equation can be rewritten in terms of magnitudes related to either the teleparallel or the riemannian structures induced in spacetime by the presence of the gravitational field. In the first case, it gives a force equation, with torsion playing the role of force. In the second, it gives the usual geodesic equation of General Relativity. The main conclusion is that scalar matter is able to feel anyone of the above spacetime geometries, the teleparallel and the metric ones. Furthermore, both descriptions are found to be completely equivalent in the sense that they give the same physical trajectory for a spinless particle in a gravitational field.Comment: Equations (44)-(47) correcte

A formal framework for a nonlocal generalization of Einstein's theory of gravitation

The analogy between electrodynamics and the translational gauge theory of gravity is employed in this paper to develop an ansatz for a nonlocal generalization of Einstein's theory of gravitation. Working in the linear approximation, we show that the resulting nonlocal theory is equivalent to general relativity with "dark matter". The nature of the predicted "dark matter", which is the manifestation of the nonlocal character of gravity in our model, is briefly discussed. It is demonstrated that this approach can provide a basis for the Tohline-Kuhn treatment of the astrophysical evidence for dark matter.Comment: 13 pages RevTex, no figures; v2: minor corrections, reference added, matches published versio