204 research outputs found

    Spontaneous Echocardiographic Contrast (SPE) – An In-Vitro Study of the Impact of Cardiac-Output, Left-Ventricular DP/DT and Temperature

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    Recent clinical studies have indicated echocardiographic observations of gaseous emboli in the left ventricle (LV) and atrium (LA) during studies in patients with mechanical heart valves (MHV) in the mitral position. These reports have shown that the intensities of these gas bubbles in elderly patients are less than those in younger patients. These facts may indicate a correlation between formation of the gas bubbles and the LV functions. The goal was to utilize our pulse duplication system to create the corresponding physiologic conditions and to understand the impact of these parameters on SpE formation

    Distribution and Extinction of Ungulates during the Holocene of the Southern Levant

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    BACKGROUND: The southern Levant (Israel, Palestinian Authority and Jordan) has been continuously and extensively populated by succeeding phases of human cultures for the past 15,000 years. The long human impact on the ancient landscape has had great ecological consequences, and has caused continuous and accelerating damage to the natural environment. The rich zooarchaeological data gathered at the area provide a unique opportunity to reconstruct spatial and temporal changes in wild species distribution, and correlate them with human demographic changes. METHODOLOGY: Zoo-archaeological data (382 animal bone assemblages from 190 archaeological sites) from various time periods, habitats and landscapes were compared. The bone assemblages were sorted into 12 major cultural periods. Distribution maps showing the presence of each ungulate species were established for each period. CONCLUSIONS: The first major ungulate extinction occurred during the local Iron Age (1,200-586 BCE), a period characterized by significant human population growth. During that time the last of the largest wild ungulates, the hartebeest (Alcelaphus buselaphus), aurochs (Bos primigenius) and the hippopotamus (Hippopotamus amphibius) became extinct, followed by a shrinking distribution of forest-dwelling cervids. A second major wave of extinction occurred only in the 19th and 20th centuries CE. Furthermore, a negative relationship was found between the average body mass of ungulate species that became extinct during the Holocene and their extinction date. It is thus very likely that the intensified human activity through habitat destruction and uncontrolled hunting were responsible for the two major waves of ungulate extinction in the southern Levant during the late Holocene
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