725 research outputs found
The variations of the δ<sup>13</sup>C and δ<sup>18</sup>O in the Middle Permian rocks, Volga river outcrops, Russia
© 2006-2017 Asian Research Publishing Network (ARPN). Data on stable isotopes of carbon and oxygen of the Permian carbonate rocks play an important role to create geochemical frame of the Permian formations. The stable isotopes records reflect changes in chemical composition of carbonate rocks in dependence on regional and global factors in history of the Permian period. Variations of stable isotopes across the Middle Permian rocks correlate with the stratigraphic boundaries and paleoenvironmental changes
Red paleosols in the key sections of the Middle and Upper Permian of the Kazan Volga region and their paleoclimatic significance
© 2015, Pleiades Publishing, Ltd. This paper presents the preliminary results of investigations of carbonate nodules from red paleosols of the reference sections of the Middle and Upper Permian of the Kazan Volga region. The main genetic types of paleosols are calcic gleysols and gleyed vertisols, the pedogenic nodules are composed of dolomite and calcite. Scanning electron microscopy and spectroscopic and isotopic methods of analysis show that the nodules retained their original mineral composition and were formed with the participation of soil microorganisms under conditions of contrasting seasonality in an arid climate. In the vicinity of the Kiama–Illawarra paleomagnetic boundary, the Urzhumian paleosols show a transition in the composition of pedogenic nodules from dolomite to calcite. It is suggested that this transition was caused by the humidization of climate, which is supported by lithological and isotopic data
ART-XC: A Medium-energy X-ray Telescope System for the Spectrum-R-Gamma Mission
The ART-XC instrument is an X-ray grazing-incidence telescope system in an ABRIXAS-type optical configuration optimized for the survey observational mode of the Spectrum-RG astrophysical mission which is scheduled to be launched in 2011. ART-XC has two units, each equipped with four identical X-ray multi-shell mirror modules. The optical axes of the individual mirror modules are not parallel but are separated by several degrees to permit the four modules to share a single CCD focal plane detector, 1/4 of the area each. The 450-micron-thick pnCCD (similar to the adjacent eROSITA telescope detector) will allow detection of X-ray photons up to 15 keV. The field of view of the individual mirror module is about 18 x 18 arcminutes(exp 2) and the sensitivity of the ART-XC system for 4 years of survey will be better than 10(exp -12) erg s(exp -1) cm(exp -2) over the 4-12 keV energy band. This will allow the ART-XC instrument to discover several thousand new AGNs
Fast X-ray Transients and Their Connection to Gamma-Ray Bursts
Fast X-ray transients (FXTs) with timescales from seconds to hours have been
seen by numerous space instruments. We have assembled archival data from
Ariel-5, HEAO-1 (A-1 and A-2), WATCH, ROSAT, and Einstein to produce a global
fluence-frequency relationship for these events. Fitting the log N-log S
distribution over several orders of magnitude to simple power law we find a
slope of -1.0. The sources of FXTs are undoubtedly heterogeneous, the -1 power
law is an approximate result of the summation of these multiple sources. Two
major contributions come from gamma-ray bursts and stellar flares.
Extrapolating from the BATSE catalog of GRBs, we find that the fraction of
X-ray flashes that can be the X-ray counterparts of gamma-ray bursts is a
function of fluence. Certainly most FXTs are not counterparts of standard
gamma-ray bursts. The fraction of FXTs from non-GRB sources, such as magnetic
stars, is greatest for the faintest FXTs. Our understanding of the FXT
phenomenon remains limited and would greatly benefit from a large, homogeneous
data set, which requires a wide-field, sensitive instrument.Comment: 36 pages, 8 figure
Шкала GRACE 2.0 для прогнозирования течения острого коронарного синдрома: какой из маркеров повреждения миокарда использовать?
Aim. To compare the effectiveness of various markers of myocardial injury (creatine phosphokinase MB-fraction (CK-MB), cardiac troponin I, measured by standard and high sensitivity methods (cTnI and hs-TnI), and heart-type fatty acids binding protein (H-FABP)) in predicting the ACS course using the GRACE 2.0 score.Methods. 183 patients with a verified diagnosis of ACS were included in the study. The levels of CK-MB, cTnl, hs-Tnl and H-FABP were measured at admission. Qualitative assessment of H-FABP was performed by immunochromatographic express-tests “CARD-INFO” and “CardioFABP”. Risk assessment of death in the in-hospital period and within the 12-months follow-up period, as well as death and/or acute myocardial infarction (AMI) within the 12-months follow-up was estimated using the GRACE 2.0 score with alternate inclusion of the various cardiomarkers. The effectiveness of the resultant prognostic scales was evaluated using the ROC-analysis and comparison of the areas under the curve (AUC).Results. 114 patients (62.3%) were diagnosed with AMI and 69 (37.7%) with unstable angina. 10 patients (5.5%) died during the indexed hospitalization. Four patients died within the follow-up and 8 patients (4.4%) had Ami. 94 patients (51.3%) had elevated hs-Tnl levels at admission, 90 patients (49.2%) - cTnl, 45 patients (24.6%) - CK-MB. H-FABP levels were elevated in 70 (38.3%). The express-test “CARD-INFO” was positive in 86 patients (47.0%), the “CardioFABP” - in 125 (68.3%). There were no significant differences found between the stratification of ACS patients by the GRACE 2.0 score into high and non-high risk groups in terms of complications (p<0.05). Similarly, there were no significant differences found between the AUC values of the cardiomarkers in terms of developing the endpoints using the GRACE 2.0 score (p<0.05).Conclusion. The introduction of H-FABP in the GRACE 2.0 scale is non-inferior to traditional markers of myocardial damage and may be used to stratify risk in patients with ACS.Цель. Сравнить эффективность прогнозирования течения острого коронарного синдрома (ОКС) с помощью шкалы GRACE 2.0 при включении в нее результатов определения различных маркеров повреждения миокарда (МВ-фрак-ции креатинфосфокиназы (МВ-КФК), сердечного тропонина I, определенного методами стандартной и высокой чувствительности (сТн I и вчТн I), и сердечного белка, связывающего жирные кислоты (сБСЖК)).Материалы и методы. В исследование включены 183 пациента с верифицированным диагнозом «ОКС». Больным при поступлении проводилось количественное определение уровня МВ-КФК, сТн I, вчТн I и сБСЖК, а также качественная оценка содержания сБСЖК с помощью иммунохроматографических экспресс-тестов «КАРД-ИНФО» и «КардиоБСЖК». Оценку риска летального исхода в стационаре и в течение 12 месяцев наблюдения, а также летального исхода и/или развития острого инфаркта миокарда (ОИМ) в течение 12 месяцев, выполняли с помощью шкалы GRACE 2.0 с поочередным использованием результатов определения различных кардиомаркеров. Эффективность полученных прогностических шкал оценивали с помощью ROC-анализа и сопоставления показателей площади под кривой (AUC).Результаты. У 114 больных (62,3%) диагностирован ОИМ, у 69 (37,7%) - нестабильная стенокардия. В течение госпитализации умерли 10 пациентов (5,5%), в течение последующего наблюдения произошло еще 4 летальных исхода и 8 случаев (4,4%) развития ОИМ. Уровень вчТн I при поступлении был повышен у 94 пациентов (51,3%), сТн I - у 90 (49,2%), МВ-КФК - у 45 (24,6%), сБСЖК, определенного количественным методом, - у 70 (38,3%). Экспресс-тест «КАРД-ИНФО» был положительным у 86 пациентов (47,0%), «КардиоБ-СЖК» - у 125 (68,3%). Результаты распределения больных ОКС на группы высокого и невысокого риска развития осложнений по шкале GRACE 2.0 в течение госпитализации и 12 мес. при использовании различных маркеров значимо не различались (p<0,05). При сравнении показателей AUC изучавшихся кардиомаркеров в отношении развития всех конечных точек с помощью шкалы GRACE 2.0 достоверных различий также не выявлено (p<0,05).Заключение. Включение в шкалу GRACE 2.0 сБСЖК по эффективности прогнозирования течения ОКС не уступает традиционным маркерам повреждения миокарда и может применяться, наряду с ними, для стратификации риска у больных ОКС
Laser-Plasma Interactions Enabled by Emerging Technologies
An overview from the past and an outlook for the future of fundamental
laser-plasma interactions research enabled by emerging laser systems
Feasibility studies of the time-like proton electromagnetic form factor measurements with PANDA at FAIR
The possibility of measuring the proton electromagnetic form factors in the
time-like region at FAIR with the \PANDA detector is discussed. Detailed
simulations on signal efficiency for the annihilation of into a
lepton pair as well as for the most important background channels have been
performed. It is shown that precision measurements of the differential cross
section of the reaction can be obtained in a wide
angular and kinematical range. The individual determination of the moduli of
the electric and magnetic proton form factors will be possible up to a value of
momentum transfer squared of (GeV/c). The total cross section will be measured up to (GeV/c).
The results obtained from simulated events are compared to the existing data.
Sensitivity to the two photons exchange mechanism is also investigated.Comment: 12 pages, 4 tables, 8 figures Revised, added details on simulations,
4 tables, 9 figure
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