183 research outputs found
Mediterranean outflow water activity on the Western Iberian Margin : evidence from a benthic foraminifer trace element study
Tracing the influence of Mediterranean outflow waters on the Mid-depth portuguese margin between Marine Isotope Stages 9 and 13
Predictors of ACEI/ARB therapy in patients with hypertrophic cardiomyopathy : results of a national registry
© The European Society of Cardiology 2018. All rights reserved. For Permissions, please e-mail: [email protected]: Angiotensin-converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB) are not considered disease-modifying drugs in hypertrophic cardiomyopathy (HCM) and their use is usually dependent on other clinical indications. Few data exist about the use of ACEI/ARB in HC in the real world, particularly in patients with intraventricular obstruction.
Objective: In this study, we sought to determine the frequency of ACEI / ARB therapy in patients with HCM and the predictors for their use.info:eu-repo/semantics/publishedVersio
Linkages between North Atlantic surface water circulation patterns and Mediterranean outflow variability on the Western Iberian Margin : examples from marine isotope stages 3 and 12 to 10
Paleoceanographic and climatic implications of a new Mediterranean Outflow branch in the southern Gulf of Cadiz
The presence of contourite drifts in the southern Gulf of Cadiz (GoC) along the Moroccan margin raises questions about the (re)circulation of Mediterranean Outflow Water (MOW) in the GoC and the origin of the currents depositing them. Here, we compare two cores representative of Iberian and Moroccan contourite drifts, covering the last 22 kyr. Although the whole sequence is contouritic in character, it reflects the interaction of distinctive silty-contourite facies (high flow velocity periods) imbedded in muddy-contourite facies (low flow velocity periods). Evidence from benthic foraminifera δ13C, sortable silt grain-size, oceanographic CTD profiles and numerical simulations, indicate the Mediterranean water mass as the source of the southern contourite deposits. Our data, therefore, suggests an additional branch of upper-MOW veering southwards off the Straits of Gibraltar along the Moroccan margin. During MIS-(Marine Isotope Stage) 2, upper-MOW was a sluggish current while in the Holocene upper-MOW dominated as a fast, semi-steady flow. Throughout the deglaciation, silty contourites associated with higher flow speeds were deposited in the northern and southern GoC during cold events such as Heinrich Stadial 1 (HS1) and the Younger Dryas, forced by global millennial-scale climate variability. Millennial variability also appears to drive the deposition of silty-contourites in the Holocene. We estimated an average duration of 1 ka for the process of depositing a fast contourite unit. The case of silty-contourite I6 (within HS1) allows us to illustrate with extremely high resolution a “rapid” sequential change in circulation, with gradual slow-down of dense Mediterranean water while surface was freshening (HS1), provoking injection of high-salinity intermediate waters (via contour-currents) into the GoC, and hence the North Atlantic. The subsequent brief collapse of dense water formation in the Mediterranean Sea triggered a major increase in sea surface temperatures (10 °C/ka) in the GoC, developing into the next interstadial (Bølling/Allerød). The impact of Mediterranean intermediate waters is manifested here by triggering a substantial rearrangement of intermediate and deep circulation in the North Atlantic, which would have further impacted the Atlantic Meridional Overturning Circulation (AMOC)
Influence of diagenetic processes and terrestrial/anthropogenic sources in the REE contents of the Cascais submarine canyon (Iberian western coast)
ABSTRACT: Temporal variations of rare earth elements (REE) and their fractionation patterns, major elements, Pb and Hg were determined in two multicores collected at 445 and 2100 m water depth (mwd) in the Cascais submarine canyon (CSC). The PAAS-normalized REE patterns suggest mixing of Tagus estuarine and marine sediments, marked by MREE (Nd‐Dy series) enrichment and by positive Eu-anomaly, with marine sediments. The positive Eu/Eu* implies incorporation of detrital feldspar minerals derived from the estuary. Ce/Ce*, (La/Yb)PAAS and (Nd/Yb)PAAS show differences between the two cores. Core 252-35 from the shallower site is enriched in HREE (Ho‐Lu series) over LREE (La‐Pr series), a pattern also found in the Tagus estuary in the vicinity of an abandoned chemical complex, where the environment is affected by the legacy of massive-sulfide ores processing. There seems to be only limited down-canyon sediment transport to the deeper reaches where core 252-32 was collected. This deeper site shows Ce/Ce* peaks coinciding with low (La/Yb)PAAS values suggesting preferential diagenetic remobilization of LREE relative to HREE. Upcore Pb/Al and Hg/Corg trends observed in both cores indicate dispersion of the anthropogenic component from the estuary through the CSC, which is less obvious from the ∑REE/Al trends particularly in the deeper site. This may suggest the influence of diagenetic processes in the REE signal, associated with relatively low sediment accumulation rates.info:eu-repo/semantics/publishedVersio
Higher frequency of turbidites during abrupt climatic "Heinrich" and "Dansgaard-Oeschger events" - evidence for slope instability on the Portuguese Margin
Submarine Cascais Canyon as a sediment conduit to the deep sea : comparison with adjacent slopes
Submarine canyons are known to be important conduits that trap, accumulate and deliver both natural and anthropogenic
sediments from the shelf to the deep sea. Ten multi-cores from the Cascais Canyon and from the neighbour slopes (off
Estremadura and Sines) were dated by 21Opb methodologies and analyzed for texture, major and trace metals to evaluate the
role of submarine canyons in the transport of anthropogenic metals to the abyssal plains. Higher accumulation mass rates were
determined in the upper Cascais Canyon than in the lower canyon and slopes. Enrichment factors (EF) were used to evaluate the
level of metal enrichment in the studied areas. EF values exceeding natural background concentrations were obtained for Pb
suggesting an anthropogenic and/or diagenetic source for Pb enrichment in the Cascais Canyon, but also, to a lesser extent, in the
Estremadura and Sines slopes. Studies of provenance based on the ratio of different stable Pb isotopes can help to determinethe
origin of such metal in the sediments
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