Search results for " wedge"
showing 10 items of 97 documents
Accretionary orogens through Earth history
2009
Accretionary orogens form at intraoceanic and continental margin convergent plate boundaries. They include the supra-subduction zone forearc, magmatic arc and back-arc components. Accretionary orogens can be grouped into retreating and advancing types, based on their kinematic framework and resulting geological character. Retreating orogens (e.g. modern western Pacific) are undergoing long-term extension in response to the site of subduction of the lower plate retreating with respect to the overriding plate and are characterized by back-arc basins. Advancing orogens (e.g. Andes) develop in an environment in which the overriding plate is advancing towards the downgoing plate, resulting in th…
Geochemical signature of Paleozoic accretionary complexes of the Central Asian Orogenic Belt in South Mongolia: Constraints on arc environments and c…
2006
Abstract We report a reconnaissance geochemical and Nd-isotopic study for 33 metaigneous and metavolcaniclastic rocks from the ca. 470 to 290 Ma old Gurvan Sayhan, Zoolen, Nemegt Uul, Bayanleg-Hatuu, and Tseel mountain ranges in southern Mongolia, in order to infer tectonic environments, test a recently proposed multiple terrane model, and explore the late-stage development of the southern Central Asian Orogenic Belt (CAOB). Samples from the Gurvan Sayhan and the Zoolen ranges have a predominantly intermediate, calc-alkaline composition; they display LREE enrichment, excess abundances of fluid-soluble elements, and low concentrations of high-field strength elements. These data, in combinati…
Circulatory response to volume expansion and transjugular intrahepatic portosystemic shunt in refractory ascites: Relationship with diastolic dysfunc…
2015
Abstract Background Cirrhotic cardiomyopathy may lead to heart failure in stressful circumstances, such as after transjugular intrahepatic portosystemic shunt (TIPS) placement. Aim To examine whether acute volume expansion predicts haemodynamic changes after TIPS and elicits signs of impending heart failure. Methods We prospectively evaluated refractory ascites patients (group A) and compensated cirrhotics (group B), who underwent echocardiography, NT-proBNP measurement, and heart catheterization before and after volume load; group A repeated measurements after TIPS. Results 15 patients in group A (80% male; 54 ± 12.4 years) and 8 in group B (100% male; 56 ± 6.2 years) were enrolled. Echoca…
Plasma levels of atrial natriuretic peptide and hemodynamic function in cardiac disease.
1993
Plasma concentrations of atrial natriuretic peptide were measured in eight patients with cardiac disease but normal resting right atrial pressure, during cardiac catheterization. No patient had clinical evidence of overt heart failure. An increase in peptide concentrations was observed between the aorta or the peripheral vein and the pulmonary artery. A linear relation was found between peripheral vein and pulmonary artery peptide concentration. Mean pulmonary artery and capillary wedge pressure also correlated with the peptide levels. No correlation was observed between mean right atrial pressure and peptide concentration. These findings demonstrate that atrial natriuretic peptide release,…
Estimation of pulmonary arterial pressure by measuring the size of the right pulmonary artery in the suprasternal echocardiogram.
1982
We studied 175 patients within 24 hr before cardiac catheterization with suprasternal echocardiography to evaluate whether pulmonary arterial hypertension can be derived by measuring the size of the right pulmonary artery. Group I consisted of 103 patients without pulmonary arterial hypertension (enddiastolic less than or equal to 12 mm Hg; mean pressure less than 20 mm Hg) and group II consisted of 72 patients with pulmonary arterial hypertension. The right pulmonary artery could be imaged in 91.2% of the patients studied. The size of the right pulmonary artery at the end of diastole in group I measured 17.9 +/- 0.2 mm (mean +/- SEM) and correlated best to the body surface area in this gro…
Pulmonary balloon angioplasty of chronic thromboembolic pulmonary hypertension (CTEPH) in surgically inaccessible cases.
2003
Abstract The clinical course of patients suffering from chronic thromboembolic pulmonary hypertension (CTEPH) depends on the distribution pattern of the thromboembolic material. In patients with thromboembolic findings in the central pulmonary segments pulmonary thrombendarterectomy (PTE) has excellent results and acceptable operative risk. This paper presents two surgically inaccessible cases that were successfully treated with balloon pulmonary angioplasty. Balloon angioplasty improved parenchymal perfusion, increased cardiac index (Delta CI +19.2 % [Case 1], and +15.4 % [2]), reduced pulmonary vascular resistance during follow-up (Delta PVRI -25.0 % [1] and -15.9 % [2]), and is discussed…
The Western Alps from the Jurassic to Oligocene: spatio-temporal constraints and evolutionary reconstructions
2005
Abstract Despite extensive research in the last 150 years, the regional tectonic reconstruction of the Western Alps has remained controversial. The curved orogenic belt consists of several ribbon-like continental terranes (Sesia/Austroalpine, Internal Crystalline Massifs, Brianconnais), which are separated by two or more ophiolitic sutures (Piemonte, Valais, Antrona?, Lanzo/Canavese?). High-pressure (HP) metamorphism of each terrane occurred during distinct orogenic episodes: at ∼65 Ma in the Sesia/Austroalpine, at ∼45 Ma in the Piemonte zone and at ∼35 Ma in the Internal Crystalline Massifs. It is suggested that these events reflect individual accretionary episodes, which together with kin…
Influence of dopexamine on hemodynamics, intramucosal pH, and regulators of the macrocirculation and microcirculation in patients undergoing abdomina…
2000
Abstract Objective: To investigate whether dopexamine hydrochloride beneficially influences splanchnic perfusion and regulators of the macrocirculation and microcirculation in patients undergoing surgery of the abdominal aorta. Design: Prospective, blinded, and randomized study. Setting: University-affiliated hospital. Participants: Twenty patients undergoing elective abdominal aortic surgery. Interventions: The patients were randomized to one of two groups. In the dopexamine group (DOP, n = 10), dopexamine, 1 μg/kg/min, was started before surgery and continued for 24 hours. In the control group (COG, n = 10), patients received saline solution as placebo. Extensive hemodynamic monitoring wa…
Noble-gas signature of magmas from a heterogeneous mantle wedge: The case of Stromboli volcano (Aeolian Islands, Italy)
2014
Abstract We report on the variation of the elemental (He, Ne, and Ar) and isotopic (He and Ar) compositions of olivine- and clinopyroxene-hosted fluid inclusions hosted in lavas, pyroclastics, and cumulate xenoliths from the last 60 ka of the eruptive history of Stromboli volcano, Italy. Samples belong to (i) the present-day activity as represented by shoshonitic (SHO) basalts, i.e., pumices with low porphyritic (LP) content and high porphyritic (HP) scoriae; (ii) the subalkaline versus alkaline products erupted at Stromboli during its subaerial history among the extreme magmatic series, i.e., calc-alkaline (CA) and potassic (KS); and (iii) the only known ultramafic cumulates (San Bartolo w…
Late Cretaceous lithospheric extension in SE China: Constraints from volcanic rocks in Hainan Island
2015
Abstract Petrological, geochemical and in-situ zircon U–Pb dating and Hf-isotope analyses have been carried out on a suite of basalt–andesite–rhyolite volcanic rocks exposed in the Liuluocun area, Hainan Island, SE China. Zircon analyses show that these volcanic rocks crystallized in the Early Cretaceous (ca. 102 Ma). The basalts are characterized by low MgO contents and mg-numbers but high rare earth element, high field strength element and large ion lithophile element contents and Nb–Ta negative anomalies. They have relatively uniform Sr–Nd isotope compositions with e Nd (t) values of − 4.09 to − 3.63. The andesites show enrichment of high field strength element and rare earth element wit…