The protection of Lake Baikal and the planning of water management measures in the Selenga River Basin require a comprehensive understanding of the current state and functioning of the delta's ecosystem and hydrogeochemical processes. This is particularly relevant in light of recent and expected future changes involving both the hydrology and water quality in the Lake Baikal basin causing spatiotemporal changes in water flow, morphology, and transport of sediments and metals in the Selenga River delta and thus impacting on delta barrier functions. The central part of the delta had been characterized by sediment storage, especially along the main channels, causing a continuous lift of the delta surface by about 0.75 cm/year-1. Theses morphological changes have a significant impact on hydrological conditions, with historical shifts in the bulk discharge from the left to the right parts of the delta which is distinguished by a relatively high density of wetlands. Regions with a high density of wetlands and small channels, in contrast to main channel regions, show a consistent pattern of considerable contaminant filtering and removal (between 77 and 99 % for key metals), during both high-flow and low-flow conditions. The removal is associated with a significant concentration increase (2-3 times) of these substances in the bottom sediment. In consequence, geomorphological processes, which govern the partitioning of flow between different channel systems, may therefore directly govern the barrier function of the delta.
Abstract:A LUCIFS model variant is presented that represents the influence of climate and land use change on fluvial systems. The study considers trends of climatic characteristics (air temperature, annual precipitation totals, rainfall erosion index, aridity and continentality coefficients) for the steppe and partially wooded steppe watersheds of the south of East Siberia (the Yenisey River macro-watershed). It also describes the influence of these characteristics on erosion processes, one indicator of which is the suspended sediment yield. Changes in the river network structure (the order of rivers, lengths, etc.) as a result of agricultural activity during the 20th century are investigated by means of analysis of maps of different dates for one of the watersheds, that of the Selenga River, the biggest tributary of Lake Baikal. The study reveals an increase of erosion process intensity in the first two-thirds of the century in the Selenga River watershed and a reduction of this intensity in the last third of the century, both in the Selenga River watershed and in most of the other watersheds of the study area.
IntroductionSpontaneous cervical-mediastinal hematoma caused by extracapsular rupture of parathyroid gland occurs extremely rarely. There are no standard treatment approaches because of the peculiarities of each case.Presentation of caseWe report herewith about a rare case of spontaneous cervical-mediastenal hematoma occured by hemorrhage in parathyroid adenoma, which was detected in an previously absolutely healthy female patient in the age of 29. This woman was hospitalized in 2 days after the manifestation, complaining about a neck ache. Indirect laryngoscopy: right-side larynx paresis. Blood test: parathyroid hormone 843 pg/ml (norm 15–65), ionized calcium 1.8 mmol/l (norm 0.9–1.1). Positive dynamics was observed throughout 8 days of anti-inflammatory therapy. Symptoms of neck organs compression increased acutely at the 9th day. The patient was operated – hematoma lancing with resection of walls. Histological examination discovered the fragments of parathyroid adenoma in the hematoma's wall. Level of ionized blood calcium got normal approximately in 24 h after the surgery. The patient was examined 6 months after the surgery. The patient had no disphagy, voice quality was intact, breathing was not restricted. Level of parathyroid hormone in blood got normal.DiscussionA rareness of this pathology and treatment variability does not allow to choose a unified medical and diagnostic tactics.ConclusionOur case demonstrates that radical correction of primary hyperparathyroidism by excision of hematoma and its fibrous capsule with preservation of thyroid gland is possible in conditions of tense cervical-mediastinal hematoma with inflammation process in the hemorrhage area.
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