82 research outputs found

    30,000 YEARS OF GROUND SURFACE TEMPERATURE AND HEAT FLUX CHANGES IN KARELIA RECONSTRUCTED FROM BOREHOLE TEMPERATURE DATA

    Get PDF
    Analyses of temperature-depth profiles logged in deep boreholes (> 1 km) permit the reconstruction of ground surface temperature (GST) and surface heat flux (SHF) histories in the period of global climate change at the border of the Pleistocene and the Holocene. We reconstructed past GST and SHF histories using data obtained from the 3.5-km-deep Onega borehole (Karelia, north-west Russia). The resulting reconstructions include information on the basal thermal regime of the Scandinavian Ice Sheet, which covered the region in the Last Glacial Maximum (LGM). The surface temperature history reveals a high amplitude of Pleistocene/ Holocene warming equal to 18–20 K. The heat flux changes precede the surface temperature changes and are close to the variations of insolation at a latitude of 60°N. A comparison of the reconstructed GST and SHF histories with the records of carbon dioxide contents in Antarctic ice cores shows that CO2 changes are much closer to temperature changes than they are to heat flux changes

    Autoresonance in a Dissipative System

    Full text link
    We study the autoresonant solution of Duffing's equation in the presence of dissipation. This solution is proved to be an attracting set. We evaluate the maximal amplitude of the autoresonant solution and the time of transition from autoresonant growth of the amplitude to the mode of fast oscillations. Analytical results are illustrated by numerical simulations.Comment: 22 pages, 3 figure

    Asymptotics for a special solution to the second member of the Painleve I hierarchy

    Full text link
    We study the asymptotic behavior of a special smooth solution y(x,t) to the second member of the Painleve I hierarchy. This solution arises in random matrix theory and in the study of Hamiltonian perturbations of hyperbolic equations. The asymptotic behavior of y(x,t) if x\to \pm\infty (for fixed t) is known and relatively simple, but it turns out to be more subtle when x and t tend to infinity simultaneously. We distinguish a region of algebraic asymptotic behavior and a region of elliptic asymptotic behavior, and we obtain rigorous asymptotics in both regions. We also discuss two critical transitional asymptotic regimes.Comment: 19 page

    Benign and malignant paragangliomas: clinical presentation and treatment outcomes in 38 patients

    Get PDF
    Paragangliomas are tumors of neuroendocrine system. Tumors are characterized by a wide variety of localizations. The article presents an analysis of 38 cases of benign and malignant paragangliomas detected between 2010 and 2019 at the Sverdlovsk Regional Oncology Center.Параганглиомы - опухоли нейроэндокринного происхождения, характеризующиеся широким разнообразием локализаций. В статье представлен анализ 38 случаев доброкачественных и злокачественных параганглиом, выявленных за период с 2010 г. по 2019 г. на базе Свердловского областного онкологического диспансера

    Peculiarities of the Accumulation of Mineral Elements and Nitrogen in the Assimilation Apparatus of Scots Pine

    Get PDF
    The research has been carried out in the Arkhangelsk forestry of the Arkhangelsk Region in a drained shrub-sphagnum pine forest. Census trees of medium diameter and height for the stand have been selected, from which samples of needles, both living and dying yellow ones, and shoots of different ages have been taken on model branches. Soil samples have also been taken from the 3 upper horizons. It has been established that most of all nitrogen and mineral elements accumulate in the living needles – 4.4 % on average, in the dying needles and shoots there are 37–40 % less. Among all the elements, nitrogen, potassium and calcium make up the largest proportion; while the rest of the chemical elements are several time less. In descending order of the share, they are arranged in the following sequence: magnesium, sulfur, phosphorus, manganese, silicon, iron and aluminum. The most important mineral elements are derived in significant quantities from the dying yellow needles. The content of sulfur, magnesium, phosphorus, manganese and iron decreases in them by 3.3, 2.1, 8.0, 1.5 and 1.4 times, respectively, compared to the living needles. Data on the presence of nitrogen and mineral elements in the soil horizons A0, T1 and T2 have been obtained. It has been established that some of the essential elements for the life of a tree are concentrated in the living needles in much larger quantities than in the soil: potassium, phosphorus, manganese and calcium – by 12.0, 4.0, 6.0 and 1.9, respectively. The yellow falling needles create a biological cycle of substances. The amount of nitrogen and ash constituents in these needles is proportional to their presence in the soil. In turn, the content of mineral elements in the shoots is close to their amount in the yellow falling needles, on the one hand, and on the other, depends on the age of the shoots. There is a steady trend of decreasing the content of nitrogen, potassium, phosphorus and sulfur with the age of the shoots

    Lenvatinib Therapy in Patients with Unresectable Hepatocellular Carcinoma in Real Clinical Practice

    Get PDF
    Aim. To determine lenvatinib treatment outcomes in patients with advanced unresectable hepatocellular carcinoma (uHCC) in real clinical practice.Patients and methods. A multicenter retrospective observational study included 58 patients with a confirmed uHCC diagnosis receiving lenvatinib. At baseline, ECOG, Child-Pugh and BCLC scores were assessed. The objective response rate (ORR), disease control rate (DCR), median overall survival (OS) and median progression-free survival (PFS) rates were assessed. In addition, adverse effects (AE) during treatment were monitored.Results. The median OS and PFS comprised 14.6 (95 % CI 10.6–18.6) and 11.1 months (95 % CI 8.31–13.8), respectively. The ORR amounted to 32.8 %, while DCR reached the level of 79.3 %. The levels of ORR and DCR were not statistically significantly different between the patients with stages B and C according to the BCLC staging system, with grades 0 and 1 according to ECOG, with classes A and B according to the Child-Pugh score, with viral and non-viral HCC etiology, with and without extrahepatic spread, and with and without portal vein invasion. Patients with alpha-fetoprotein (AFP) blood levels <200 ng/mL showed significantly higher ORR and DCR compared to those with AFP levels >200 ng/mL (44.4 % vs. 13.6 %, p = 0.015; and 88.9 % vs. 63.6 %, p = 0.021, respectively). The uHCC stage according to BCLC, ECOG functional status, Child-Pugh class, presence or absence of extrahepatic spread and viral etiology had no effect on the OS and PFS median levels. Patients with macroscopic portal vein invasion had a significantly lower PFS compared with those lacking this complication: 3.97 (0.00-8.07) vs. 11.1 (8.46-13.7), p = 0.053. AFP levels ≥200 ng/mL adversely affected survival rates: median OS comprised 12.0 (5.95-18.9) months in the group of patients with AFP ≥200 ng/mL vs. 16.1 (8.73-23.5) months in the group of patients having AFP <200 ng/mL, p = 0.020. AEs were registered in 81.0% (n = 47) of patients. Among the most common AEs were arterial hypertension (32.8 %), weakness (24.1 %), weight loss (12.1 %) and appetite loss (10.3 %). Due to AEs, Lenvatinib was withdrawn in 5 (8.6 %) patients.Conclusion. Lenvatinib confirmed its efficacy and safety in patients with uHCC in real clinical practice. The treatment outcome might be affected by AFP levels and the presence of macroscopic portal vein invasion. Further comparative studies into treatment regimens applied in real clinical practice are required

    Properties of field functionals and characterization of local functionals

    Get PDF
    Functionals (i.e. functions of functions) are widely used in quantum field theory and solid-state physics. In this paper, functionals are given a rigorous mathematical framework and their main properties are described. The choice of the proper space of test functions (smooth functions) and of the relevant concept of differential (Bastiani differential) are discussed. The relation between the multiple derivatives of a functional and the corresponding distributions is described in detail. It is proved that, in a neighborhood of every test function, the support of a smooth functional is uniformly compactly supported and the order of the corresponding distribution is uniformly bounded. Relying on a recent work by Yoann Dabrowski, several spaces of functionals are furnished with a complete and nuclear topology. In view of physical applications, it is shown that most formal manipulations can be given a rigorous meaning. A new concept of local functionals is proposed and two characterizations of them are given: the first one uses the additivity (or Hammerstein) property, the second one is a variant of Peetre's theorem. Finally, the first step of a cohomological approach to quantum field theory is carried out by proving a global Poincar\'e lemma and defining multi-vector fields and graded functionals within our framework.Comment: 32 pages, no figur
    corecore