Ischemic heart disease still represents a large burden on individuals and health care resources worldwide. By conventions, it is equated with atherosclerotic plaque due to flow-limiting obstruction ...in large-medium sized coronary arteries. However, clinical, angiographic and autoptic findings suggest a multifaceted pathophysiology for ischemic heart disease and just some cases are caused by severe or complicated atherosclerotic plaques. Currently there is no well-defined assessment of ischemic heart disease pathophysiology that satisfies all the observations and sometimes the underlying mechanism to everyday ischemic heart disease ward cases is misleading. In order to better examine this complicated disease and to provide future perspectives, it is important to know and analyze the pathophysiological mechanisms that underline it, because ischemic heart disease is not always determined by atherosclerotic plaque complication. Therefore, in order to have a more complete comprehension of ischemic heart disease we propose an overview of the available pathophysiological paradigms, from plaque activation to microvascular dysfunction.
We present a study on the prediction of rogue waves during the 1-hour sea state of Hurricane Joaquin when the Merchant Vessel El Faro sank east of the Bahamas on October 1, 2015. High-resolution ...hindcast of hurricane-generated sea states and wave simulations are combined with novel probabilistic models to quantify the likelihood of rogue wave conditions. The data suggests that the El Faro vessel was drifting at an average speed of approximately 2.5 m/s prior to its sinking. As a result, we estimated that the probability that El Faro encounters a rogue wave whose crest height exceeds 14 meters while drifting over a time interval of 10 (50) minutes is ~1/400 (1/130). The largest simulated wave is generated by the constructive interference of elementary spectral components (linear dispersive focusing) enhanced by bound nonlinearities. Not surprisingly then, its characteristics are quite similar to those displayed by the Andrea, Draupner and Killard rogue waves.
Since the 1990s, the modulational instability has commonly been used to explain the occurrence of rogue waves that appear from nowhere in the open ocean. However, the importance of this instability ...in the context of ocean waves is not well established. This mechanism has been successfully studied in laboratory experiments and in mathematical studies, but there is no consensus on what actually takes place in the ocean. In this work, we question the oceanic relevance of this paradigm. In particular, we analyze several sets of field data in various European locations with various tools, and find that the main generation mechanism for rogue waves is the constructive interference of elementary waves enhanced by second-order bound nonlinearities and not the modulational instability. This implies that rogue waves are likely to be rare occurrences of weakly nonlinear random seas.
We study channel turbulence by interpreting its vorticity as a random sea of ocean wave packet analogues. In particular, we investigate the ocean-like properties of vortical packets applying ...stochastic methods developed for oceanic fields. Taylor's hypothesis of frozen eddies does not hold when turbulence is not weak, and vortical packets change shape as they are advected by the mean flow, altering their own speed. This is the physical manifestation of a hidden wave dispersion of turbulence. Our analysis at the bulk Reynolds number Re
= 5600 suggests that turbulent fluctuations behave dispersively as gravity-capillary waves, with capillarity being dominant near the wall region.
Abstract
We present a statistical analysis of deep-water buoy measurements of large waves generated during two major storms of the Eastern Mediterranean in 2017 and 2018, respectively. The largest ...waves observed do display similar characteristics to those of the Draupner, Andrea, and El Faro rogue waves in that second order bound nonlinearities enhance the linear dispersive focusing of extreme waves. We also present a novel analysis of waves in space-time to predict potential risks posed by such large waves to navigation. In particular, we consider the scenario of two types of vessels of the Israeli Navy fleet navigating during the most intense stages of the two storms considered here and provide predictions for the largest waves likely to be encountered.
The severe acute respiratory syndrome coronavirus 2 (Sars-CoV-2) global pandemic is a devastating event that is causing thousands of victims every day around the world. One of the main reasons of the ...great impact of coronavirus disease 2019 (COVID-19) on society is its unexpected spread, which has not allowed an adequate preparation. The scientific community is fighting against time for the production of a vaccine, but it is difficult to place a safe and effective product on the market as fast as the virus is spreading. Similarly, for drugs that can directly interfere with viral pathways, their production times are long, despite the great efforts made. For these reasons, we analyzed the possible role of non-pharmacological substances such as supplements, probiotics, and nutraceuticals in reducing the risk of Sars-CoV-2 infection or mitigating the symptoms of COVID-19. These substances could have numerous advantages in the current circumstances, are generally easily available, and have negligible side effects if administered at the already used and tested dosages. Large scientific evidence supports the benefits that some bacterial and molecular products may exert on the immune response to respiratory viruses. These could also have a regulatory role in systemic inflammation or endothelial damage, which are two crucial aspects of COVID-19. However, there are no specific data available, and rigorous clinical trials should be conducted to confirm the putative benefits of diet supplementation, probiotics, and nutraceuticals in the current pandemic.
Heart failure is a complex syndrome responsible for high rates of death and hospitalization. Ischemic heart disease is one of the most frequent causes of heart failure and it is normally attributed ...to coronary artery disease, defined by the presence of one or more obstructive plaques, which determine a reduced coronary blood flow, causing myocardial ischemia and consequent heart failure. However, coronary obstruction is only an element of a complex pathophysiological process that leads to myocardial ischemia. In the literature, attention paid to the role of microcirculation, in the pathophysiology of ischemic heart disease and heart failure, is growing. Coronary microvascular dysfunction determines an inability of coronary circulation to satisfy myocardial metabolic demands, due to the imbalance of coronary blood flow regulatory mechanisms, including ion channels, leading to the development of hypoxia, fibrosis and tissue death, which may determine a loss of myocardial function, even beyond the presence of atherosclerotic epicardial plaques. For this reason, ion channels may represent the link among coronary microvascular dysfunction, ischemic heart disease and consequent heart failure.
Significant new information shows that the Campanian Ignimbrite (CI) eruption from the Phlegrean Fields, southern Italy, was much larger than hitherto supposed and in fact one of the largest late ...Quaternary explosive events. The eruption can be dated to 40,000 calendar years ago, within the interval of the so-called Middle to Upper Paleolithic ‘transition’. Its position can be precisely correlated with a number of other environmental events, including Heinrich Event 4 (HE4), the Laschamp excursion, and a particular cosmogenic nuclide peak. In view of this unique combination of factors, we studied the CI volcanic catastrophe with particular attention to its impact on climate and human ecosystems, including potential interference with ongoing processes of cultural evolution (biological evolution is best left aside for the moment). The contribution of this research is chronological and ecological. The CI volcanic event provides an unequalled means of correlating stratigraphic sequences across Western Eurasia, either directly or indirectly, and affords a unique opportunity to establish the age and climatic context of important archaeological sequences. Ecologically, the CI eruption inevitably interacted with the beginning of HE4 in terms of atmospheric feedback systems. Their combined forcing produced a sudden and at least hemispheric climatic deterioration; a ‘volcanic winter’ scenario cannot be ruled out. Paleolithic occupation was severely altered throughout the direct-impact zone of the eruption and likely along fringe areas in southern and southeastern Europe. The above observations call for a reconsideration of the processes and rhythms involved in the Middle to Upper Paleolithic ‘transition’. A tentative model is suggested that links the exceptional environmental stress at 40,000
BP with processes already active in Paleolithic societies, leading to a period of accelerated change in cultural configurations. These eventually evolved into an Upper Paleolithic proper at a later date. The evidence to invoke allochthonous cultural input or invasionist scenarios is not considered compelling.
Alpe Borghetto Moe, Dagfinn; Fedele, Francesco G.
Vegetation history and archaeobotany,
03/2019, Letnik:
28, Številka:
2
Journal Article
Recenzirano
The origins of Alpe Borghetto, a present-day summer farm complex in Val Febbraro (Italian central Alps), were investigated in 1996–2004 on the basis of five peat mires at 1,895–2,103 m a.s.l. which ...were analysed palynologically, and five main archaeological sites at 2,015–2,115 m. The area appears to have started to be used in the Neolithic according to environmental evidence at Borghetto Sotto, around 4500–3800 cal BC. Increased human land use during the Copper and/or Bronze Age is indicated by pollen results from the Barch and Lavazzé sites and by archaeological findings at Lavazzé. Some kind of regular summer activity may have taken place at Lavazzé and perhaps in the Barch area along the natural tree line. In the early Iron Age, a substantial reduction of woodland around 800–500 cal BC at Barch probably marks the beginning of traditional dairying-based summer farming in the area, soon followed by a ‘protohistoric’/early Medieval settlement at Barch. A year-round settlement of similar date appeared at lower altitude in the nearby valley of Starleggia, following Bronze Age woodland clearance. A subsequent decrease in charcoal input at Barch can be associated with the period when mountain farmers left the zone and settled lower down at present-day Borghetto, as evidenced from Borghetto Sotto. This resettlement was possibly brought about by a lack of wood for building, fuel and tools, and may have taken place over many centuries during the Middle Ages. Pressures from Iron Age economies within and around the Alps might have influenced the appearance of traditional summer farming in Val Febbraro.
Objectives The aim of this study was to determine whether clinical presentation and type of cell death in acute myocarditis might contribute to cardiac magnetic resonance (CMR) sensitivity. ...Background Growing evidence indicates CMR is the reference noninvasive tool for the diagnosis of acute myocarditis. However, factors affecting CMR sensitivity are still unclear. Methods We retrospectively evaluated 57 consecutive patients with a diagnosis of acute myocarditis made on the basis of clinical history (≤3 months) and endomyocardial biopsy evidence of lymphocytic infiltrates (≥14 infiltrating leukocytes/mm2 at immunohistochemistry) in association with damage of the adjacent myocytes and absence or minimal evidence of myocardial fibrosis. CMR acquisition protocol included T2-weighted (edema), early (hyperemia), and late (fibrosis/necrosis) gadolinium enhancement sequences. Presence of ≥2 CMR criteria denoted myocarditis. Type of cell death was evaluated by using in situ ligation with hairpin probes. Results Three clinical myocarditis patterns were recognized: infarct-like (pattern 1, n = 21), cardiomyopathic (pattern 2, n = 21), and arrhythmic (pattern 3, n = 15). Tissue edema was observed in 81% of pattern 1, 28% of pattern 2, and 27% of pattern 3. Early enhancement was evident in 71% of pattern 1, 67% of pattern 2, and 40% of pattern 3. Late gadolinium enhancement was documented in 71% of pattern 1, 57% of pattern 2, and 47% of pattern 3. CMR sensitivity was significantly higher in pattern 1 (80%) compared with pattern 2 (57%) and pattern 3 (40%) (p < 0.05). Cell necrosis was the prevalent mechanism of death in pattern 1 compared with pattern 2 (p < 0.001) and pattern 3 (p < 0.05), whereas apoptosis prevailed in pattern 2 (p < 0.001 vs. pattern 1 and p < 0.05 vs. pattern 3). Conclusions In acute myocarditis, CMR sensitivity is high for infarct-like, low for cardiomyopathic, and very low for arrhythmic clinical presentation; it correlates with the extent of cell necrosis–promoting expansion of interstitial space.
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