93 research outputs found
New data on the chronology of the Vale do Forno sedimentary sequence (Lower Tejo River terrace staircase) and its relevance as a fluvial archive of the Middle Pleistocene in western Iberia
The Vale do Forno archaeological sites (Alpiar\ue7a, central Portugal) document the earliest human occupation
in the Lower Tejo River, well established in geomorphological and environmental terms, within
the Middle Pleistocene. In a staircase of six fluvial terraces, the Palaeolithic sites were found on the T4
terrace (\ufe24 m, above river bed) which is made of a basal Lower Gravels unit (LG) and an overlying Upper
Sands unit (US). Geomorphological mapping, coupled with lithostratigraphy, sedimentology and luminescence
dating (quartz-OSL and K-feldspar post-IRIR290) were used in this study. The oldest artefacts
found in the LG unit show crude bifacial forms that can be attributed to the Acheulian. In contrast, the US
unit has archaeological sites stratigraphically documenting successive phases of an evolved Acheulian.
Luminescence dating and correlation with the Marine Isotopic Stages suggest that the LG unit has a
probable age of ca. 335 to 325 ka and the US unit an age of ca. 325 to 155 ka. This is in contrast to
previous interpretations ascribing this terrace (and lithic industries) to the Last Interglacial and early
phases of the Last Glacial. The VF3 site (Milharos), containing Micoquian (Final Acheulian) industries
(with fine and elaborated bifaces), found in a stratigraphic level located between the T4 terrace deposits
and a colluvium associated with Late Pleistocene aeolian sands, is younger than 155 ka but much older
than 32 ka
Bicuspid aortic valve: a literature review and its impact on sport activity.
The bicuspid aortic valve (BAV) is the most common congenital cardiac malformation. A literature search was performed using the key words 'bicuspid aortic valve', 'pathophysiology', 'exercise' and 'training'. BAV is the result of a complex developmental process where several genes seem to lead to abnormal valvulogenesis. Complications associated with BAV include aortic stenosis (AS) and regurgitation, infective endocarditis and aortic dilation and dissection. Moreover, BAV may be associated with other cardiovascular anomalies, mainly aortic coarctation. There is greater awareness of BAV in the young population who practice sport, with an increasing interest on the impact of regular and competitive exercise on athletes with BAV. The early identification of BAV through pre-participation screening is of paramount importance, and the justification of the more appropriate diagnostic methods is still an area of debate. A normally functioning BAV usually does not represent a limit for practising sport. The stress of regular and intense exercise on an abnormal aortic valve may favour its early deterioration and accelerate the development of complications. Therefore, athletes with BAV warrant regular follow-up, which should include echocardiographic assessment at least every year. The eligibility for participation and ability to continue to practise competitive sports in athletes with BAV cannot be generalized, but needs to be individualized depending on age, severity of lesions and type of sport. Further studies are required to elucidate the impact of physical training and competitive sports on the natural course of the BAV
- …