High-resolultion reconstruction of Lena River discharge during the Late Holocene inferred from microalgae assemblages

On the basis of a detailed study of the diatom and aquatic palynomorph assemblages and a detailed radiocarbon chronology of sediment cores obtained from the south-eastern inner Laptev Sea shelf adjacent to the Lena Delta the spatial and temporal variability in the Lena River discharge during the last 6 cal. ka were reconstructed. It was shown that in the area adjacent to the Lena Delta variations in surface water salinities, reconstructed using freshwater diatoms as a proxy, were mainly caused by changes in the volume of the Lena River runoff through the major riverine channels Trofimovskaya, Bykovskaya and Tumatskaya. Several paleohydrological phases are recognized: (i) establishment of modern-like conditions within the eastern Lena River Valley occurred from 6-4.2 cal. ka; (ii) Lena River outflow increased in north-eastward direction via the Trofimovskaya or Bykovskaya channels from 4.2-2.7 cal. ka, coeval with a reduction of runoff toward the north via the Tumatskaya Channel; (iii) generally stable hydrological conditions northward of the Tumatskaya Channel and variations in riverine discharge north-eastward of the Trofimovskaya and Bykovskaya channels prevail since 2.7 cal. ka. Using indicator species of dinocysts as principle marine proxy, an influence of Atlantic water to the southeast inner Laptev Sea shelf could be inferred, possibly along the Eastern Lena paleovalley, brought into this area by winddriven reversed bottom currents. Zusammenfassung: Untersuchungen von Diatomeen- und aquatischen Palynomorphen-Vergesellschaftungen wurden an Radiokohlenstoff datierten Sedimentkernen aus der inneren südöstlichen Laptevsee nahe des Lenadeltas durchgeführt. Anhand dieser Daten wurde die zeitliche und räumliche Veränderlichkeit des Flusswasserausstromes der Lena für die letzten 6 ka (Kalenderjahre) rekonstruiert. Zeitliche Veränderungen in den Häufigkeiten von Süßwasserdiatomeen sind begründet durch Wechsel in der Menge des Lenaausflusses durch die drei großen Haupkanäle im Delta: Trofimovskaja, Bykovskja, sowie Tumatskaja. Darauf basierend konnten prinzipiell drei große paläohydrologische Phasen unterschieden werden: (1) heutigen Verhältnissen vergleichbare Bedingungen wurden östlich des Lenadeltas zwischen 6 und 4.2 ka etabliert; (2) Erhöhung des Flusswasseraustrags in nordöstliche Richtung über die Kanäle Trofimovskaja und/oder Bykovskaja zwischen 4.2 und 2.7 ka bei gleichzeitiger Reduzierung Richtung Norden via Tumatskaja; (3) Ausbildung relativ stabiler Bedingungen nördlich des Deltas sowie Auftreten wechselhafter Flusswasserausträgen in östliche Richtung nach 2.7 ka. Das Auftreten von marinen Dinocysten in den Sedimenkernen belegt den Einfluss von Wassermassen mit vermutlich atlantischem Ursprung. Es ist zu vermuten, dass diese durch windgetriebene Bodenströmungen entlang der alten versunkenen Flusstäler auf den östlichen inneren Schelf verfrachtet werden

РЕГЕНЕРАТИВНЫЕ ОСОБЕННОСТИ ТКАНИ ПЕЧЕНИ ПОСЛЕ ОСТАНОВКИ КРОВОТЕЧЕНИЯ НЕРАВНОВЕСНОЙ ПЛАЗМОЙ НА 90-е И 180-е СУТКИ (ЭКСПЕРИМЕНТАЛЬНОЕ ИССЛЕДОВАНИЕ)

Liver damages occur to 17.8% of blunt abdominal trauma cases. Postoperative mortality in liver damage is a high. It amounts to 4–10% in case of stab wounds, to 30.4–35,2% in case of closed injury, to 39.3% in case of concomitant injury. Complete hemostasis without damage to organ parenchyma is needed for liver surgical operation.The aim of research is to evaluate the regenerative characteristics of liver tissue after hemostasis by nonequilibrium plasma in a long-term period.Material and methods. Research was performed on 20 laboratory rats, 3 experimental groups. 10 intact animals and 5 animals in groups on 90th and 180th day. Surgery is resection of liver left lobe and coagulation with cold plasma coagulator. The biochemical control (glucose, ALT, AST, total bilirubin, direct, alkaline phosphatase, total protein, urea, α-amylase, CRP, fibrinogen, aPTT, PTT, INR), morphological study of rat liver were performed.Results. After surgery with cold plasma hemostasis animals are active, early begin to eat. Fatal cases are not. Analysis of biochemical markers doesn't reveal statistically significant differences from the norm for the majority of indicators. Decrease of glucose concentration in the blood serum is observed in a long-term period. Histological analysis reveals an increase of the central and interlobular veins and moderate signs of edema on the 90th day. Hepatocytes with pronounced signs of protein and fatty degeneration are identified. Liver histology corresponds to the usual structure and is represented by liver lobules, separated by a small layer of connective tissue on the 180th day.Conclusion. Cold plasma coagulation in liver surgery showed effective hemostasis, minimal trauma of organ parenchyma, the lack of systemic effect and the subsequent complete regeneration of liver tissue in the treatment area.Частота повреждений печени при тупой травме живота может достигать 17,8% случаев. Послеоперационная летальность при повреждениях печени высока и составляет при колото-резаных ранах 4–10%, закрытой травме – 30,4–35,2%, сочетанной травме – до 39,3%. Для обеспечения хирургического пособия на печени необходим полный гемостаз без повреждения паренхимы органа.Цель исследования – оценить регенеративные особенности ткани печени после остановки кровотечения неравновесной плазмой в отдаленные сроки.Материал и методы. Эксперимент проводили на 20 лабораторных крысах-самцах, которые были разделены на 3 группы: 10 интактных животных (контроль) и по 5 крыс в группах на 90-е и 180-е сут после оперативного вмешательства. Выполняли атипичную резекцию левой доли печени и коагуляцию холодной плазмой. Проводили биохимический контроль (глюкоза, АЛТ, АСТ, билирубин общий, прямой, ЩФ, общий белок, мочевина, α-амилаза, СРБ), для исследования печени животных использовали морфологический метод.Результаты. После оперативного вмешательства с применением холодноплазменной коагуляции животные были активны, рано начинали питаться, летальные случаи отсутствовали. При анализе биохимических показателей крови не выявлено статистически значимых отличий от нормы для большинства показателей. На отдаленные сроки отмечалось снижение концентрации глюкозы в сыворотке крови. При гистологическом исследовании на 90-е сут наблюдались увеличение центральных и междольковых вен и умеренные признаки отека. Определялись гепатоциты с выраженными признаками белковой и жировой дистрофии. На 180-е сут гистология железы соответствовала обычному строению и была представлена печеночными дольками, разделенными небольшими прослойками соединительной ткани.Заключение. Холодноплазменная коагуляция при оперативных вмешательствах на печени показала эффективную остановку кровотечения, минимальную травму паренхимы органа, отсутствие системного эффекта и последующую полную регенерацию тканей печени в области обработки

Table 1: Diatom distribution in surface sediments of the Kara Sea

Diatom assemblages in 62 surface sediment samples from the outer Ob and Yenisei estuaries and the adjacent inner Kara Sea shelf were examined in relation to environmental conditions. Concentrations of diatoms reflect the biological productivity of surface waters along with specific water mass processes of diatom valve deposition in the zone of intermixing of riverine and marine waters. An inverse relationship between total concentration of diatom valves in sediments and surface water salinity is found. Extremely high abundances of diatom valves (up to 82.4 million valves/g sediment) are observed in the outer Ob and Yenisei estuaries (salinity 10-20%) correspond to the mean interannual location of the winter polynya corroborating previously obtained results from the Laptev Sea

Interactive Learning Technologies to Build Students' Interest in Cross-Cultural Communication

The article is devoted to the use of case-studies, group discussions, role-plays, imitative modeling and other interactive methods of teaching to build up students' interest in having communicative skills and socio-cultural knowledge necessary for effective cross-cultural communication

Holocene paleoenvironmental implications of diatom and organic carbon records from the Southeastern Kara Sea (Siberian Margin)

Diatom assemblages and organic carbon records from two sediment cores located within an estuarian bay of the inner Kara Sea trace changes in Yenisei River runoff and postglacial depositional environments. Paleosalinity and sea-ice reconstructions are based on modern relationships of local diatom assemblages and summer surface-water salinity. Approximately 15,500 cal yr B.P., rivers and bogs characterized the study area. When sea level reached the 38- to 40-m paleo-isobath approximately 9300 cal yr B.P., the coring site was flooded. From 9300–9100 cal yr B.P., estuarine conditions occurred proximal to the depocenter of fluvially derived material, and salinity was <7–8. Paleosalinity increased to 11–13 by 7500 cal yr B.P., following postglacial sea-level rise and the southward shift of the Siberian coast. Sharp decreases in diatom accumulation rates, total sediment, and organic carbon also occurred, suggesting the presence of brackish conditions and greater distance between the coast and study site. Maximum paleosalinity (up to 13) was recorded between 7500 and 6000 cal yr B.P., which was likely caused by the enhanced penetration of Atlantic waters to the Kara Sea. Stepwise decreases to modern salinity levels happened over the last 6000 cal yr