79 research outputs found

    Origin of Nepheline-normative High-K Ankaramites and the Evolution of Eastern Srednogorie Arc in SE Europe

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    Eastern Srednogorie is part of the Apuseni-Banat-Timok-Srednogorie magmatic belt in SE Europe, the main arc related to the Late Cretaceous subduction and closure of the Tethys Ocean between Africa and Europe. Extrusive and shallow intrusive magmatism in the Eastern Srednogorie is abundant and extremely diverse in composition, covering a wide range from ultramafic volcanic rocks to granites; this provides a unique opportunity to study processes of primitive melt formation and magma evolution in an arc environment. In contrast to other parts of the belt, relatively mafic lavas predominate here. Three magmatic regions are distinguished within Eastern Srednogorie from south to north: Strandzha, Yambol-Burgas and East Balkan. Systematic differences exist between these regions, notably the increased alkalinity of samples from the Yambol-Burgas region in the central part. All rocks display a clear subduction-like signature in their trace-element patterns, particularly the enrichment in large ion lithophile elements and light rare earth elements relative to high field strength elements. A distinct primitive nepheline-normative ankaramite magma type is recognized among the mafic volcanic rocks from the Yambol-Burgas region and melt inclusions entrapped in olivine and clinopyroxene from a cumulitic rock. Lower crustal clinopyroxene and amphibole cumulates carried to the surface as xenoliths in a mafic dike represent a possible source for the ankaramite. Modeling of the melting process suggests that low degrees of batch melting of a clinopyroxene-rich, amphibole-bearing source similar to the cumulate xenoliths at 1 GPa, temperatures of 1240-1300°C, oxidized conditions and a water content of 0·2 wt % reproduce accurately most of the observed major- and trace-element characteristics of the studied ankaramites. The elevated Rb, K2O, Th, Ba content and higher Pb isotope ratios of the predicted liquids compared with the ankaramites are explained by mixing of the ankaramite magma with lherzolite partial melts derived from the subduction-modified mantle wedge. Underplating of such mantle-derived magmas at the crust-mantle boundary in an extensional environment as a response to slab roll-back provides also the necessary heat to melt lower crustal cumulates. Fractional crystallization of mainly clinopyroxene plus olivine and Fe-Ti oxides in a deep (equivalent to 8 kbar pressure) magma chamber produced most of the observed range of shoshonitic basalts and basaltic andesites in Eastern Srednogorie. The more evolved intermediate varieties were probably formed by mixing and crystallization at lower temperatures in lower pressure magma chambers. Whole-rock Sr and Pb isotope compositions indicate variable degrees of admixing of basement rocks to generate the intermediate to acid Late Cretaceous magmas, but assimilation was minimal for magmas with less than 53 wt % SiO2. The proposed model for the evolution of the magmatism in Eastern Srednogorie involves initial formation of the calc-alkaline and high-K arc magmatism in the Strandzha and East Balkan regions, followed by roll-back induced intra-arc rifting and the formation of high-K, shoshonitic and ultra-high-K magmatism, including primitive ankaramites in the Yambol-Burgas regio

    The hidden symbiotic star SU Lyn-detection of flickering in U band

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    We report photometric observations of the hidden symbiotic star SU Lyn in the optical bands. In four nights we detect a weak flickering in U band with amplitude of about 0.05 magnitudes. No intranight variations are found in B, V, g’ and r’ bands. This is one more indication that the secondary component is a white dwarf accreting at a low accretion rate Ẇe also searched for intranight variability of a dozen related objects-RR Boo, RT Boo, AM Cyg, AG Peg, BF Cyg, NQ Gem, StHa190, V627 Cas, XX Oph, FS Cet and Y Gem-however no variability above the observational errors is detected

    Rhodiola rosea L.:from golden root to green cell factories

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    Baseline characteristics of patients in the reduction of events with darbepoetin alfa in heart failure trial (RED-HF)

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    <p>Aims: This report describes the baseline characteristics of patients in the Reduction of Events with Darbepoetin alfa in Heart Failure trial (RED-HF) which is testing the hypothesis that anaemia correction with darbepoetin alfa will reduce the composite endpoint of death from any cause or hospital admission for worsening heart failure, and improve other outcomes.</p> <p>Methods and results: Key demographic, clinical, and laboratory findings, along with baseline treatment, are reported and compared with those of patients in other recent clinical trials in heart failure. Compared with other recent trials, RED-HF enrolled more elderly [mean age 70 (SD 11.4) years], female (41%), and black (9%) patients. RED-HF patients more often had diabetes (46%) and renal impairment (72% had an estimated glomerular filtration rate <60 mL/min/1.73 m2). Patients in RED-HF had heart failure of longer duration [5.3 (5.4) years], worse NYHA class (35% II, 63% III, and 2% IV), and more signs of congestion. Mean EF was 30% (6.8%). RED-HF patients were well treated at randomization, and pharmacological therapy at baseline was broadly similar to that of other recent trials, taking account of study-specific inclusion/exclusion criteria. Median (interquartile range) haemoglobin at baseline was 112 (106–117) g/L.</p> <p>Conclusion: The anaemic patients enrolled in RED-HF were older, moderately to markedly symptomatic, and had extensive co-morbidity.</p&gt

    RATIONAL PHARMACOTHERAPY IN TAKOTSUBO CARDIOMYOPATHY

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    Rational pharmacotherapy in Takotsubo cardiomyopathy is based on clinical picture and data of functional and laboratory investigations of concrete patient. In patients with hypotension and moderate-to-severe left ventricle outflow tract obstruction inotropic agents must not to be used because they can worsen the degree of obstruction. In these patients beta blockers can improve hemodynamics by causing resolution of the obstruction. If intraventricular thrombus is detected, anticoagulation for at least 3 months is recommended. The duration of anticoagulant therapy may be modified depending on the extent of cardiac function recovery and thrombus resolution. For patients without thrombus but with severe left ventricular dysfunction, anticoagulation is recommended until the akinesis or dyskinesis has resolved but not more than 3 months

    RATIONAL PHARMACOTHERAPY IN TAKOTSUBO CARDIOMYOPATHY

    Get PDF
    Rational pharmacotherapy in Takotsubo cardiomyopathy is based on clinical picture and data of functional and laboratory investigations of concrete patient. In patients with hypotension and moderate-to-severe left ventricle outflow tract obstruction inotropic agents must not to be used because they can worsen the degree of obstruction. In these patients beta blockers can improve hemodynamics by causing resolution of the obstruction. If intraventricular thrombus is detected, anticoagulation for at least 3 months is recommended. The duration of anticoagulant therapy may be modified depending on the extent of cardiac function recovery and thrombus resolution. For patients without thrombus but with severe left ventricular dysfunction, anticoagulation is recommended until the akinesis or dyskinesis has resolved but not more than 3 months.</p
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