Rehabilitation for Cardiac Arrhythmia in COVID-19 and Non COVID-19 Patients

Introduction Exercise-based cardiorespiratory rehabilitation programme is an effective intervention to improve clinical outcomes, exercise capacity and quality of life in individuals living with cardiac and pulmonary conditions. Despite the effectiveness of the programme in cardiac population, no routine prescription of comprehensive rehabilitation is offered to those with AF. This thesis aimed to assess the benefits of the programme in those with HF and co-existing AF and to investigate the views toward delivering the programme for this population. Moreover, evidence suggests that an adapted rehabilitation programme is effective in improving clinical outcomes in those with post COVID-19 syndrome. Thus, we aimed to investigate the potential benefits of the programme in restoring cardiac autonomic functions and cardiac disturbance that might be present in this population. Methods Four main study designs were undertaken to address the thesis aims. 1. Retrospective analysis to investigate the benefits of the programme in HF individuals with AF. 2. Survey study to assess HCP views toward delivering the programme for individuals with AF. 3. Survey and interviews to investigate the need for rehabilitation for individuals with AF. 4. Observational study to assess the benefits of the programme for individual with post COVID-19. Results Rehabilitation programme demonstrated an improvement in clinical outcomes in individuals with HF and co-existing AF. HCPs were enthusiastic about the benefits of the programme for individuals living with AF. Moreover, those living with AF reported their need for this programme to help manage their symptoms. Lastly, an adapted rehabilitation programme demonstrated an improvement in cardiac autonomic function and other clinical measures in those with post COVID-19 syndrome. Conclusion Rehabilitation programme is an effective intervention for those with HF and co-existing AF, while an adapted rehabilitation programme demonstrated an improvement in cardiac functions in those with post COVID-19.</p

Tropical forcing and ENSO dominate Holocene climates in South Africa’s southern Cape

This paper explores the Holocene climatic dynamics of South Africa's southern Cape, a region that supports a large proportion of the Greater Cape Floristic Region and contains an array of important archaeological sites. While South African climates are generally characterised by marked rainfall seasonality, the southern Cape is currently situated at the interface between tropical and temperate climate systems, resulting in a largely aseasonal rainfall regime. This regime, however, is thought to have been particularly sensitive to past changes in late Quaternary boundary conditions, meaning that variability in either tropical or temperate systems could have significant environmental impacts. Evidence of past climate change, however, remains limited. We present a 9000-year record of hydroclimatic variability obtained from rock hyrax midden stable nitrogen records, from Papkuilsfontein, on the southern slope of the Anysberg Mountains. Resolved to an average 6-year resolution and spanning the period c. 9050 cal yr BP to 1990 CE, this is the highest resolution Holocene record from southern Africa and presents a unique opportunity for the detailed study of the primary drivers and spatial gradients of Holocene climate change in the southern Cape. The data indicate a long-term decrease in aridity across the Holocene and a pattern of variability that reveals remarkable similarities with records from the South African tropics and El Niño–Southern Oscillation proxies, highlighting the significance of tropical systems as drivers of Holocene climate change in the region. This substantially expands what has been previously considered to be the zone of tropical influence, extending from a coastal phenomenon associated with heat transport via the Agulhas Current to encompass much, if not all, of the Agulhas Plain south of the Cape Fold Mountains. These findings provide a valuable new climatic framework for contextualizing changes in ecological and archaeological records in the southern Cape, and contribute to a more comprehensive understanding of the spatio-temporal dynamics of climate systems in southern Africa

Genetic testing in patients with unexplained coronary aneurysms or dilation

Coronary artery dilatation (defined in CAAR – Coronary Artery Aneurysm Registry - as a diameter exceeding 1.5x an adjacent normal coronary segment or the largest normal artery) is evident in at least 0.35% of all diagnostic coronary angiograms. 1 Coronary aneurysms arediscrete dilated segments bounded by normal coronary segments. Coronary dilation may also be more diffuse, often involving the proximal and mid vessel with a normal calibre distal vessel. In contrast to arterial dilation in other vascular beds, coronary dilation is not usually progressive and rupture appears very rare (1/1565 recorded in CAAR survivors over 37.2 months follow-up). 1 The main clinical sequelae is coronary thrombosis leading to acute myocardial infarction. Patients followed up after an angiographic finding of coronary dilation have high major adverse cardiovascular event rates (31% at 37.2 months). [Opening paragraph]</p

How pressure affects costs of power conversion machinery in compressed air energy storage; part II: Heat exchangers

In the field of compressed air energy storage, a critical economic aspect that has been overlooked in existing literature relates to the influence of storage pressure on the capital cost of power conversion system. In Part I, a comprehensive study was conducted to address this question focusing on compressors and expanders. This part is devoted to the heat exchangers and basically assesses the engineering rationale behind the relationship between the cost per kW for HXs and operating pressure. Based on the performed analysis, the operating pressure of a HX impacts two crucial cost-related factors: the heat transfer area and required tube thicknesses. Higher operating pressures are associated with the smaller heat transfer area tending to lower costs, but increasing pressure raises tube thickness requirements, tending to increase costs. Below approximately 200 bar, the former effect prevails over the latter, leading to cost reductions with rising pressure. Conversely, at higher pressures, the latter effect outweighs the former, resulting in cost increases with increasing pressure. On the other hand, as the number of compression stages is increased to attain higher storage pressures, there is a noteworthy variation in the cost contribution of HXs. Specifically, the contribution of HX costs within the PCS machinery escalates from 10 % at a storage pressure of 30 bar to approximately 35% at a storage pressure of 350bar. This cost increase is accompanied by a substantial reduction in costs associated with other PCS machinery components (compressors and expanders), ultimately justifying the advantages of operating at higher storage pressures

Understanding cardiometabolic risk profile: the effect of aerobic exercise training, symptoms, and COVID-19

Presence of long-term conditions have been linked to morbidity and premature mortality. Preventing and reducing modifiable risk factors of long-term conditions improve symptoms and quality of life as well as reduce the risk of complications and premature mortality in populations with long-term conditions. This thesis aims to identify populations with increased cardiometabolic risk and understand whether breathlessness could influence this risk, as well as identify a possible intervention for reducing cardiovascular risk. Cardiometabolic profiles of adult survivors of severe COVID-19 were compared with COVID naïve healthy controls to understand whether COVID-19 may be linked to an increased risk of cardiometabolic diseases. Cardiometabolic risk indicators were also compared between adults with exertional breathlessness and healthy controls as well as post-COVID participants with and without breathlessness. A systematic review was also conducted to explore the effect of aerobic exercise training on pulse wave velocity in adults with and without long-term conditions. Adult survivors of severe COVID-19 had an increased cardiometabolic risk compared to the healthy group, however breathlessness was not associated with an increased risk in this cohort. There was no difference in cardiometabolic risk indicators between adults with and without exertional breathlessness, although this study had a small sample size due to the restrictions of the COVID-19 pandemic. The systematic review showed that aerobic exercise training significantly reduces pulse wave velocity in health and disease and that age was the inversely associated with this reduction.</p

AGN STORM 2. V. Anomalous Behavior of the C iv Light Curve of Mrk 817*

An intensive reverberation mapping campaign of the Seyfert 1 galaxy Mrk 817 using the Cosmic Origins Spectrograph on the Hubble Space Telescope revealed significant variations in the response of broad UV emission lines to fluctuations in the continuum emission. The response of the prominent UV emission lines changes over an ∼60 day duration, resulting in distinctly different time lags in the various segments of the light curve over the 14 month observing campaign. One-dimensional echo-mapping models fit these variations if a slowly varying background is included for each emission line. These variations are more evident in the C iv light curve, which is the line least affected by intrinsic absorption in Mrk 817 and least blended with neighboring emission lines. We identify five temporal windows with a distinct emission-line response, and measure their corresponding time delays, which range from 2 to 13 days. These temporal windows are plausibly linked to changes in the UV and X-ray obscuration occurring during these same intervals. The shortest time lags occur during periods with diminishing obscuration, whereas the longest lags occur during periods with rising obscuration. We propose that the obscuring outflow shields the broad UV lines from the ionizing continuum. The resulting change in the spectral energy distribution of the ionizing continuum, as seen by clouds at a range of distances from the nucleus, is responsible for the changes in the line response.</p

The Effect of Sedentary Behaviour on Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis

Background: Cardiorespiratory fitness (CRF) is an important indicator of current and future health. While the impact of habitual physical activity on CRF is well established, the role of sedentary behaviour (SB) remains less understood. Objective: We aimed to determine the effect of SB on CRF. Methods: Searches were conducted in MEDLINE, Embase, PsycINFO, CINAHL and SPORTDiscus from inception to August 2022. Randomised controlled trials, quasi-experimental studies and cohort studies that assessed the relationship between SB and CRF were eligible. Narrative syntheses and meta-analyses summarised the evidence, and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) certainty was based on evidence from randomised controlled trials. Results: This review included 18 studies that focused on youth (four randomised controlled trials, three quasi-experimental studies, 11 cohort studies) and 24 on adult populations (15 randomised controlled trials, five quasi-experimental studies, four cohort studies). In youth and adults, evidence from randomised controlled trials suggests mixed effects of SB on CRF, but with the potential for interventions to improve CRF. Quasi-experimental and cohort studies also support similar conclusions. Certainty of evidence was very low for both age groups. A meta-analysis of adult randomised controlled trials found that interventions targeting reducing SB, or increasing physical activity and reducing SB, had a significant effect on post-peak oxygen consumption (mean difference = 3.16 mL.kg–1.min–1, 95% confidence interval: 1.76, 4.57). Conclusions: Evidence from randomised controlled trials indicates mixed associations between SB and CRF, with the potential for SB to influence CRF, as supported by meta-analytical findings. Further well-designed trials are warranted to confirm the relationship between SB and CRF, explore the effects of SB independent from higher intensity activity, and investigate the existence of such relationships in paediatric populations. Clinical Trial Registration: PROSPERO CRD42022356218

Simultaneous Inference of Past Demography and Selection from the Ancestral Recombination Graph under the Beta Coalescent

The reproductive mechanism of a species is a key driver of genome evolution. The standard Wright-Fisher model for the reproduction of individuals in a population assumes that each individual produces a number of offspring negligible compared to the total population size. Yet many species of plants, invertebrates, prokaryotes or fish exhibit neutrally skewed offspring distribution or strong selection events yielding few individuals to produce a number of offspring of up to the same magnitude as the population size. As a result, the genealogy of a sample is characterized by multiple individuals (more than two) coalescing simultaneously to the same common ancestor. The current methods developed to detect such multiple merger events do not account for complex demographic scenarios or recombination, and require large sample sizes. We tackle these limitations by developing two novel and different approaches to infer multiple merger events from sequence data or the ancestral recombination graph (ARG): a sequentially Markovian coalescent (SMβC) and a graph neural network (GNNcoal). We first give proof of the accuracy of our methods to estimate the multiple merger parameter and past demographic history using simulated data under the β-coalescent model. Secondly, we show that our approaches can also recover the effect of positive selective sweeps along the genome. Finally, we are able to distinguish skewed offspring distribution from selection while simultaneously inferring the past variation of population size. Our findings stress the aptitude of neural networks to leverage information from the ARG for inference but also the urgent need for more accurate ARG inference approaches.</p

Co-teaching in higher education: Reflections from an early career academic

Co-teaching has been regularly used as a pedagogical tool in K-12 and postsecondary learning environments for decades, yet its practice in higher education institutions has only recently started to grow in popularity. This paper builds on recent recommendations for effective co-teaching in tertiary teaching settings by offering critical reflections and suggestions for practice from an early career academic that specialises in academic literacies. Key concepts explored include developing co-teaching norms and pedagogies through a community of practice, establishing two-way dialogue, diversifying strengths of teaching teams, and enforcing continual reflection and feedback. The paper also provides contextualised guidance notes, so that university educators and program managers have a clearer direction as to how co-teaching teams could be implemented across a range of higher education teaching programs

Minimal cover of high-dimensional chaotic attractors by embedded coherent structures

We propose a general method for constructing a minimal cover of high-dimensional chaotic attractors by embedded coherent structures, such as periodic orbits. By minimal cover we mean a finite subset of periodic orbits such that any point on the attractor is within a predefined proximity threshold to a periodic orbit within the subset. The proximity measure can be chosen with considerable freedom and adapted to the properties of a given attractor. On the example of a Kuramoto-Sivashinsky chaotic attractor, we demonstrate that the minimal cover can be faithfully constructed even when the proximity measure is defined within a subspace of dimension much smaller than the dimension of space containing the attractor. We discuss how the minimal cover can be used to provide reduced characterisation of the attractor structure and dynamics on it