1,686 research outputs found

    Traces of volcanic ash from the Mediterranean, Iceland and North America in a Holocene record from South Wales, UK

    Get PDF
    A tephra record is presented for a sediment core from Llyn Llech Owain, south Wales, spanning the early‐ to mid‐Holocene. Seven cryptotephra deposits are discovered with three thought to correlate with known eruptions and the remaining four considered to represent previously undocumented events. One deposit is suggested to correlate with the ~6.9 cal ka bp Lairg A tephra from Iceland, whereas more distant sources are proposed as the origin for two of the tephra deposits. A peak of colourless shards in early‐Holocene sediments is thought to tentatively correlate with the ~9.6 cal ka bp Fondi di Baia tephra (Campi Flegrei) and a second cryptotephra is tentatively correlated with the ~3.6 cal ka bp Aniakchak (CFE) II tephra (Alaska). The Fondi di Baia tephra has never been recorded beyond proximal sites and its discovery in south Wales significantly extends the geographical distribution of ash from this eruption. The remaining four cryptotephra deposits are yet to be correlated with known eruptions, demonstrating that our current understanding of widespread tephra deposits is incomplete. This new tephra record highlights the potential for sites at more southerly and westerly locations in northwest Europe to act as repositories for ash from several volcanic regions

    Mitochondrial and nuclear genes suggest that stony corals are monophyletic but most families of stony corals are not (Order Scleractinia, Class Anthozoa, Phylum Cnidaria)

    Get PDF
    Modern hard corals (Class Hexacorallia; Order Scleractinia) are widely studied because of their fundamental role in reef building and their superb fossil record extending back to the Triassic. Nevertheless, interpretations of their evolutionary relationships have been in flux for over a decade. Recent analyses undermine the legitimacy of traditional suborders, families and genera, and suggest that a non-skeletal sister clade (Order Corallimorpharia) might be imbedded within the stony corals. However, these studies either sampled a relatively limited array of taxa or assembled trees from heterogeneous data sets. Here we provide a more comprehensive analysis of Scleractinia (127 species, 75 genera, 17 families) and various outgroups, based on two mitochondrial genes (cytochrome oxidase I, cytochrome b), with analyses of nuclear genes (ßtubulin, ribosomal DNA) of a subset of taxa to test unexpected relationships. Eleven of 16 families were found to be polyphyletic. Strikingly, over one third of all families as conventionally defined contain representatives from the highly divergent "robust" and "complex" clades. However, the recent suggestion that corallimorpharians are true corals that have lost their skeletons was not upheld. Relationships were supported not only by mitochondrial and nuclear genes, but also often by morphological characters which had been ignored or never noted previously. The concordance of molecular characters and more carefully examined morphological characters suggests a future of greater taxonomic stability, as well as the potential to trace the evolutionary history of this ecologically important group using fossils

    Cardiovascular risk factors, cardiovascular disease, and COVID-19: an umbrella review of systematic reviews

    Get PDF
    Aims: To consolidate evidence to determine (i) the association between cardiovascular risk factors and health outcomes with coronavirus 2019 (COVID-19); and (ii) the impact of COVID-19 on cardiovascular health. Methods and results: An umbrella review of systematic reviews was conducted. Fourteen medical databases and pre-print servers were searched from 1 January 2020 to 5 November 2020. The review focused on reviews rated as moderate or high-quality using the AMSTAR 2 tool. Eighty-four reviews were identified; 31 reviews were assessed as moderate quality and one was high-quality. The following risk factors were associated with higher mortality and severe COVID-19: renal disease [odds ratio (OR) (95% confidence interval) for mortality 3.07 (2.43–3.88)], diabetes mellitus [OR 2.09 (1.80–2.42)], hypertension [OR 2.50 (2.02–3.11)], smoking history [risk ratio (RR) 1.26 (1.20–1.32)], cerebrovascular disease [RR 2.75 (1.54–4.89)], and cardiovascular disease [OR 2.65 (1.86–3.78)]. Liver disease was associated with higher odds of mortality [OR 2.81 (1.31–6.01)], but not severe COVID-19. Current smoking was associated with a higher risk of severe COVID-19 [RR 1.80 (1.14–2.85)], but not mortality. Obesity associated with higher odds of mortality [OR 2.18 (1.10–4.34)], but there was an absence of evidence for severe COVID-19. In patients hospitalized with COVID-19, the following incident cardiovascular complications were identified: acute heart failure (2%), myocardial infarction (4%), deep vein thrombosis (7%), myocardial injury (10%), angina (10%), arrhythmias (18%), pulmonary embolism (19%), and venous thromboembolism (25%). Conclusion: Many of the risk factors identified as associated with adverse outcomes with COVID-19 are potentially modifiable. Primary and secondary prevention strategies that target cardiovascular risk factors may improve outcomes for people following COVID-19

    Association of Exercise-Based Cardiac Rehabilitation with Progression of Paroxysmal to Sustained Atrial Fibrillation.

    Get PDF
    Progression of atrial fibrillation (AF) is associated with worsened prognosis for cardiovascular events and mortality. Exercise-based-cardiac rehabilitation programmes have shown preliminary promise for primary and secondary prevention of AF. Yet, such interventions are typically reserved for patients with acute coronary syndrome or undergoing revascularization. Using a retrospective cohort design, the present study investigated the association of exercise-based cardiac rehabilitation on the progression of paroxysmal to sustained AF, compared to propensity-matched controls. Patients with a diagnosis of paroxysmal AF were compared between those with and without an electronic medical record of exercise-based cardiac rehabilitation within 6-months of diagnosis. Using cox regression models, we ascertained odds of 2-year incidence for AF progression. This cohort of 9808 patients with paroxysmal AF demonstrated that exercise-based cardiac rehabilitation was associated with 26% lower odds of AF progression (odds ratio 0.74, 95% CI 0.66-0.83) compared to propensity-matched controls. This beneficial effect seemed to vary across patient subgroups. In conclusion, findings revealed that exercise-based cardiac rehabilitation was associated with significantly lower odds of progression from paroxysmal to sustained AF at 2-years follow-up compared to propensity-matched controls

    Exercise-Based Cardiac Rehabilitation and All-Cause Mortality Among Patients With Atrial Fibrillation.

    Get PDF
    Background There is limited evidence of long-term impact of exercise-based cardiac rehabilitation (CR) on clinical end points for patients with atrial fibrillation (AF). We therefore compared 18-month all-cause mortality, hospitalization, stroke, and heart failure in patients with AF and an electronic medical record of exercise-based CR to matched controls. Methods and Results This retrospective cohort study included patient data obtained on February 3, 2021 from a global federated health research network. Patients with AF undergoing exercise-based CR were propensity-score matched to patients with AF without exercise-based CR by age, sex, race, comorbidities, cardiovascular procedures, and cardiovascular medication. We ascertained 18-month incidence of all-cause mortality, hospitalization, stroke, and heart failure. Of 1 366 422 patients with AF, 11 947 patients had an electronic medical record of exercise-based CR within 6-months of incident AF who were propensity-score matched with 11 947 patients with AF without CR. Exercise-based CR was associated with 68% lower odds of all-cause mortality (odds ratio, 0.32; 95% CI, 0.29-0.35), 44% lower odds of rehospitalization (0.56; 95% CI, 0.53-0.59), and 16% lower odds of incident stroke (0.84; 95% CI, 0.72-0.99) compared with propensity-score matched controls. No significant associations were shown for incident heart failure (0.93; 95% CI, 0.84-1.04). The beneficial association of exercise-based CR on all-cause mortality was independent of sex, older age, comorbidities, and AF subtype. Conclusions Exercise-based CR among patients with incident AF was associated with lower odds of all-cause mortality, rehospitalization, and incident stroke at 18-month follow-up, supporting the provision of exercise-based CR for patients with AF

    Atrial Fibrillation in Patients With Cardiomyopathy: Prevalence and Clinical Outcomes From Real-World Data

    Get PDF
    BACKGROUND: Cardiomyopathy is a common cause of atrial fibrillation (AF) and may also present as a complication of AF. However, there is a scarcity of evidence of clinical outcomes for people with cardiomyopathy and concomittant AF. The aim of the present study was therefore to characterize the prevalence of AF in major subtypes of cardiomyopathy and investigate the impact on important clinical outcomes. METHODS AND RESULTS: A retrospective cohort study was conducted using electronic medical records from a global federated health research network, with data primarily from the United States. The TriNetX network was searched on January 17, 2021, including records from 2002 to 2020, which included at least 1 year of follow-up data. Patients were included based on a diagnosis of hypertrophic, dilated, or restrictive cardiomyopathy and concomitant AF. Patients with cardiomyopathy and AF were propensity-score matched for age, sex, race, and comorbidities with patients who had a cardiomyopathy only. The outcomes were 1-year mortality, hospitalization, incident heart failure, and incident stroke. Of 634 885 patients with cardiomyopathy, there were 14 675 (2.3%) patients with hypertrophic, 90 117 (7.0%) with restrictive, and 37 685 (5.9%) with dilated cardiomyopathy with concomitant AF. AF was associated with significantly higher odds of all-cause mortality (odds ratio [95% CI]) for patients with hypertrophic (1.26 [1.13–1.40]) and dilated (1.36 [1.27–1.46]), but not restrictive (0.98 [0.94–1.02]), cardiomyopathy. Odds of hospitalization, incident heart failure, and incident stroke were significantly higher in all cardiomyopathy subtypes with concomitant AF. Among patients with AF, catheter ablation was associated with significantly lower odds of all-cause mortality at 12 months across all cardiomyopathy subtypes. CONCLUSIONS: Findings of the present study suggest AF may be highly prevalent in patients with cardiomyopathy and associated with worsened prognosis. Subsequent research is needed to determine the usefulness of screening and multisdisciplinary treatment of AF in this population

    A retrospective and agenda for future research on Chinese outward foreign direct investment

    Get PDF
    Our original paper “The determinants of Chinese Outward Foreign Direct Investment” was the first theoretically based empirical analysis of the phenomenon. It utilised internalisation theory to show that Chinese state-owned firms reacted to home country market imperfections to surmount barriers to foreign entry arising from naivety and the lack of obvious ownership advantages, leveraging institutional factors including favourable policy stimuli. This special theory explained outward foreign direct investment (OFDI) but provided surprises. These included the apparent appetite for risk evinced by these early investors, causing us to conjecture that domestic market imperfections, particularly in the domestic capital market, might be responsible. The article stimulated a massive subsequent, largely successful, research effort on emerging country multinationals. In this Retrospective article we review some of the main strands of research that ensued, for the insight they offer for the theme of our commentary. Our theme is that theoretical development can only come through embracing yet more challenging, different, and new contexts, and we make suggestions for future research directions
    corecore