A role for the equatorial undercurrent in the ocean dynamical thermostat

Author Posting. © American Meteorological Society, 2018. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Climate 31 (2018): 6245-6261, doi:10.1175/JCLI-D-17-0513.1.Reconstructions of sea surface temperature (SST) based on instrumental observations suggest that the equatorial Pacific zonal SST gradient has increased over the twentieth century. While this increase is suggestive of the ocean dynamical thermostat mechanism of Clement et al., observations of a concurrent weakening of the zonal atmospheric (Walker) circulation are not. Here we show, using heat and momentum budget calculations on an ocean reanalysis dataset, that a seasonal weakening of the zonal atmospheric circulation is in fact consistent with cooling in the eastern equatorial Pacific (EEP) and thus an increase in the zonal SST gradient. This cooling is driven by a strengthening Equatorial Undercurrent (EUC) in response to decreased upper-ocean westward momentum associated with weakening equatorial zonal wind stress. This process can help to reconcile the seemingly contradictory twentieth-century trends in the tropical Pacific atmosphere and ocean. Moreover, it is shown that coupled general circulation models (CGCMs) do not correctly simulate this process; we identify a systematic bias in the relationship between changes in equatorial surface zonal wind stress in the EEP and EUC strength that may help to explain why observations and CGCMs have opposing trends in the zonal SST gradient over the twentieth century.2019-01-1

Physiological and clinical consequences of relief of right ventricular outflow tract obstruction late after repair of congenital heart defects.

BACKGROUND: Right ventricular outflow tract obstruction (RVOTO) is a common problem after repair of congenital heart disease. Percutaneous pulmonary valve implantation (PPVI) can treat this condition without consequent pulmonary regurgitation or cardiopulmonary bypass. Our aim was to investigate the clinical and physiological response to relieving RVOTO. METHODS AND RESULTS: We studied 18 patients who underwent PPVI for RVOTO (72% male, median age 20 years) from a total of 93 who had this procedure for various indications. All had a right ventricular outflow tract (RVOT) gradient >50 mm Hg on echocardiography without important pulmonary regurgitation (less than mild or regurgitant fraction <10% on magnetic resonance imaging [MRI]). Cardiopulmonary exercise testing, tissue Doppler echocardiography, and MRI were performed before and within 50 days of PPVI. PPVI reduced RVOT gradient (51.4 to 21.7 mm Hg, P<0.001) and right ventricular systolic pressure (72.8 to 47.3 mm Hg, P<0.001) at catheterization. Symptoms and aerobic (25.7 to 28.9 mL.kg(-1).min(-1), P=0.002) and anaerobic (14.4 to 16.2 mL.kg(-1).min(-1), P=0.002) exercise capacity improved. Myocardial systolic velocity improved acutely (tricuspid 4.8 to 5.3 cm/s, P=0.05; mitral 4.7 to 5.5 cm/s, P=0.01), whereas isovolumic acceleration was unchanged. The tricuspid annular velocity was not maintained on intermediate follow-up. Right ventricular end-diastolic volume (99.9 to 89.7 mL/m2, P<0.001) fell, whereas effective stroke volume (43.7 to 48.3 mL/m2, P=0.06) and ejection fraction (48.0% to 56.8%, P=0.01) increased. Left ventricular end-diastolic volume (72.5 to 77.4 mL/m2, P=0.145), stroke volume (45.3 to 50.6 mL/m2, P=0.02), and ejection fraction (62.6% to 65.8%, P=0.03) increased. CONCLUSIONS: PPVI relieves RVOTO, which leads to an early improvement in biventricular performance. Furthermore, it reduces symptoms and improves exercise tolerance. These findings have important implications for the management of this increasingly common condition

Theorizing healthy settings: a critical discussion with reference to Healthy Universities

The settings approach appreciates that health determinants operate in settings of everyday life. Whilst subject to conceptual development, we argue that the approach lacks a clear and coherent theoretical framework to steer policy, practice and research. Aims: To identify what theories and conceptual models have been used in relation to the implementation and evaluation of Healthy Universities. Methods: A scoping literature review was undertaken between 2010-2013, identifying 26 papers that met inclusion criteria. Findings: Seven theoretical perspectives or conceptual frameworks were identified: the Ottawa Charter; a socio-ecological approach (which implicitly drew on sociological theories concerning structure and agency); salutogenesis; systems thinking; whole system change; organisational development; and a framework proposed by Dooris. These were used to address interrelated questions on the nature of a setting, how health is created in a setting, why the settings approach is a useful means of promoting health, and how health promotion can be introduced into and embedded within a setting. Conclusion: Although distinctive, the example of Healthy Universities drew on common theoretical perspectives that have infused the settings discourse more generally. This engagement with theory was at times well-developed and at other times a passing reference. The paper concludes by pointing to other theories that offer value to healthy settings practice and research and by arguing that theorisation has a key role to play in understanding the complexity of settings and guiding the planning, implementation and evaluation of programmes

Impact of Renal Impairment on Beta-Blocker Efficacy in Patients With Heart Failure.

BACKGROUND: Moderate and moderately severe renal impairment are common in patients with heart failure and reduced ejection fraction, but whether beta-blockers are effective is unclear, leading to underuse of life-saving therapy. OBJECTIVES: This study sought to investigate patient prognosis and the efficacy of beta-blockers according to renal function using estimated glomerular filtration rate (eGFR). METHODS: Analysis of 16,740 individual patients with left ventricular ejection fraction <50% from 10 double-blind, placebo-controlled trials was performed. The authors report all-cause mortality on an intention-to-treat basis, adjusted for baseline covariates and stratified by heart rhythm. RESULTS: Median eGFR at baseline was 63 (interquartile range: 50 to 77) ml/min/1.73 m2; 4,584 patients (27.4%) had eGFR 45 to 59 ml/min/1.73 m2, and 2,286 (13.7%) 30 to 44 ml/min/1.73 m2. Over a median follow-up of 1.3 years, eGFR was independently associated with mortality, with a 12% higher risk of death for every 10 ml/min/1.73 m2 lower eGFR (95% confidence interval [CI]: 10% to 15%; p < 0.001). In 13,861 patients in sinus rhythm, beta-blockers reduced mortality versus placebo; adjusted hazard ratio (HR): 0.73 for eGFR 45 to 59 ml/min/1.73 m2 (95% CI: 0.62 to 0.86; p < 0.001) and 0.71 for eGFR 30 to 44 ml/min/1.73 m2 (95% CI: 0.58 to 0.87; p = 0.001). The authors observed no deterioration in renal function over time in patients with moderate or moderately severe renal impairment, no difference in adverse events comparing beta-blockers with placebo, and higher mortality in patients with worsening renal function on follow-up. Due to exclusion criteria, there were insufficient patients with severe renal dysfunction (eGFR <30 ml/min/1.73 m2) to draw conclusions. In 2,879 patients with atrial fibrillation, there was no reduction in mortality with beta-blockers at any level of eGFR. CONCLUSIONS: Patients with heart failure, left ventricular ejection fraction <50% and sinus rhythm should receive beta-blocker therapy even with moderate or moderately severe renal dysfunction

Electromagnetic interactions of high energy cosmic my muons

Electromagnetic interactions of high energy muons incident in the nearly horizontal direction at Durham, I98 ft. above sea level, have been studied by detecting electron-photon bursts produced in iron absorbers. Over the measured burst size range, bremsstrahlung and knock-on electron production were the predominant energy transfer processes. No divergence from accepted theory has been observed for energy transfer in the range 3 - 240 GeV. A second burst experiment has been performed to measure the spectra of nuclear-active particles incident at Durham in the nearly vertical direction. The observed spectra of both charged and neutral nuclear-active particles show a discontinuity at energies >100 GeV, which can be taken as support for the SU(_3) prediction that a protonis a tightly bound system of three charged quarks. This interpretation would indicate a quark mass of 10 GeV, and that high energy protons dissociate into their constituent quarks in about l8^ of their collisions above threshold (18OO GeV). A further implication isthat quarks interact strongly in the atmosphere, otherwise telescope detectors would have recorded an abundance of quarks. A decrease-2in the nucleon attenuation length from 127 gm. cm to a value ofp117 gm. cm(^-2) for sea level nucleon energies > 100 GeV would also account for the observed discontinuity

Differential response to resistance training in CHF according to ACE genotype

The Angiotensin Converting Enzyme (ACE) gene may influence the risk of heart disease and the response to various forms of exercise training may be at least partly dependent on the ACE genotype. We aimed to determine the effect of ACE genotype on the response to moderate intensity circuit resistance training in chronic heart failure (CHF) patients. Methods: The relationship between ACE genotype and the response to 11 weeks of resistance exercise training was determined in 37 CHF patients (New York Heart Association Functional Class=2.3±0.5; left ventricular ejection fraction 28±7%; age 64±12 years; 32:5 male:female) who were randomised to either resistance exercise (n=19) or inactive control group (n=18). Outcome measures included V˙ O2peak, peak power output and muscle strength and endurance. ACE genotype was determined using standard methods. Results: At baseline, patients who were homozygous for the I allele had higher V˙ O2peak (p=0.02) and peak power (p=0.003) compared to patients who were homozygous for the D allele. Patients with the D allele, who were randomised to resistance training, compared to non-exercising controls, had greater peak power increases (ID pb0.001; DD pb0.001) when compared with patients homozygous for the I allele, who did not improve. No significant genotype-dependent changes were observed in V˙ O2peak, muscle strength, muscle endurance or lactate threshold. Conclusion: ACE genotype may have a role in exercise tolerance in CHF and could also influence the effectiveness of resistance training in this condition

Combined heart-liver transplantation for failing Fontan circulation in a late survivor with single-ventricle physiology

Management of adults with failing Fontan physiology poses many challenges, especially as transplantation offers the only realistic alternative to palliative care. We present the first combined heart and liver transplant performed in Europe, for a late survivor of single ventricle palliation with the Fontan circulation. In addition to the conventional medical and surgical challenges posed, we highlight the management of the associated multi-organ failure with focus on the liver and novel strategies for assessment and optimization

Ambulatory Care in Adult Congenital Heart Disease—Time for Change?

\ua9 2022 by the authors. Licensee MDPI, Basel, Switzerland.Background: The adult congenital heart disease (ACHD) population is growing in size and complexity. This study evaluates whether present ambulatory care adequately detects problems and considers costs. Methods: A UK single-centre study of clinic attendances amongst 100 ACHD patients (40.4 years, median ACHD AP class 2B) between 2014 and 2019 and the COVID-19 restrictions period (March 2020–July 2021). Results: Between 2014 and 2019, there were 575 appointments. Nonatten-dance was 10%; 15 patients recurrently nonattended. Eighty percent of appointments resulted in no decision other than continued review. Electrocardiograms and echocardiograms were frequent, but new findings were rare (5.1%, 4.0%). Decision-making was more common with the higher ACHD AP class and symptoms. Emergency admissions (n = 40) exceeded elective (n = 25), with over half following unremarkable clinic appointments. Distance travelled to the ACHD clinic was 14.9 km (1.6–265), resulting in 433–564 workdays lost. During COVID 19, there were 127 appointments (56% in-person, 41% telephone and 5% video). Decisions were made at 37% in-person and 19% virtual consultations. Nonattendance was 3.9%; there were eight emergency admissions. Conclusion: The main purpose of the ACHD clinic is surveillance. Presently, the clinic does not sufficiently predict or prevent emergency hospital admissions and is costly to patient and provider. COVID-19 has enforced different methods for delivering care that require further evaluation

Is perception of quality more important than technical quality in patient video cases?

Background: The use of video cases to demonstrate key signs and symptoms in patients (patient video cases or PVCs) is a rapidly expanding field. The aims of this study were to evaluate whether the technical quality, or judgement of quality, of a video clip influences a paediatrician's judgment on acuity of the case and assess the relationship between perception of quality and the technical quality of a selection of video clips. Methods: Participants (12 senior consultant paediatricians attending an examination workshop) individually categorised 28 PVCs into one of 3 possible acuities and then described the quality of the image seen. The PVCs had been converted into four different technical qualities (differing bit rates ranging from excellent to low quality). Results: Participants' assessment of quality and the actual industry standard of the PVC were independent (333 distinct observations, spearmans rho = 0.0410, p = 0.4564). Agreement between actual acuity and participants' judgement was generally good at higher acuities but moderate at medium/low acuities of illness (overall correlation 0.664). Perception of the quality of the clip was related to correct assignment of acuity regardless of the technical quality of the clip (number of obs = 330, z = 2.07, p = 0.038). Conclusions: It is important to benchmark PVCs prior to use in learning resources as experts may not agree on the information within, or quality of, the clip. It appears, although PVCs may be beneficial in a pedagogical context, the perception of quality of clip may be an important determinant of an expert's decision making. © 2015 Roland et al