Backwash sediment record of the 2009 South Pacific Tsunami and 1960 Great Chilean Earthquake Tsunami.

Following recent tsunamis, most studies have focused on the onshore deposits, while the offshore backwash deposits, crucial for a better understanding of the hydrodynamic processes during such events and offering an opportunity for sedimentary archives of past tsunamis, have mostly been omitted. Here, we present a unique sedimentary record of the backwash from two historical tsunamis sampled in a sheltered bay in American Samoa, namely the 2009 South Pacific Tsunami and the 1960 Great Chilean Earthquake Tsunami. Although not always concomitant with a marked grain size change, backwash deposits are identified by terrestrial geochemical and mineralogical signatures, associated with basal soft sediment micro-deformations. These micro-deformations, including asymmetric flame structures, are described for the first time in historic shallow marine backwash deposits and lead us to propose an improved depositional mechanism for tsunami backflow based on hyperpycnal currents. Moreover, this study brings a potential new criterion to the proxy toolkit for identifying tsunami backwash deposits, namely the basal soft sediment micro-deformations. We suggest that further studies focus on these micro-deformations in order to test the representability of this criterion for tsunami backwash deposits. Sheltered shallow marine environments in areas repeatedly impacted by tsunamis have a higher potential for the reconstruction of paleo-tsunami catalogs and should be preferentially investigated for coastal risk assessment.

Improvements in cardiac function detected using echocardiography in patients with hereditary haemochromatosis.

BACKGROUND: Hereditary haemochromatosis is often not diagnosed until adulthood. Iron overload cardiomyopathy initially results in diastolic dysfunction and can result in arrhythmias and irreversible cardiac failure if untreated. The aim of this study was to investigate whether patients with newly diagnosed hereditary haemochromatosis without signs of heart failure exhibit subclinical alterations of cardiac function and to determine if cardiac function improved after 1 year of venesection. METHODS: Baseline echocardiography was performed on 25 patients with newly diagnosed hereditary haemochromatosis with elevated serum ferritin levels. The test was repeated after 1 year of treatment with venesection. Tissue Doppler imaging (TDI) and deformation (strain) imaging using speckle tracking were performed. Left atrial force was measured according to the Newtonian principle, in which force (dynes) = mass × acceleration. Left atrial force was calculated by the Manning method expressed as ρ × 0.53 × mitral annular orifice area × (peak A velocity)2. RESULTS: Radial strain showed a significant improvement after 1 year of venesection (increase from 38.8 to 52.6). The LAF showed a significant decrease after 1 year of venesection (median decrease = 0.6 (IQR 0, 1.60), p = 0.0004). Iso-volumetric relaxation time (IVRT) decreased significantly in patients after 1 year of venesection (decrease from 107.4 ± 16.2 to 97.68 ± 15.4 ms, p (0.0187)). CONCLUSION: Among all measurements, radial strain, IVRT and left atrial force were shown to significantly improve following a 1-year course of venesection, suggesting that these parameters could be used to identify subclinical cardiac dysfunction in patients with iron overload secondary to hereditary haemochromatosis and to guide intensification of venesection therapy.