216 research outputs found
Strategy of protection against hazardous channel and hydrological processes in rivers of developed territories and territories with focal development
In 2012-2015, the Makkaveev Research Laboratory of Soil Erosion and Fluvial Processes of MSU, Department of Geography, carried out a research, including analysis of hydrological and channel regimes of the Tom river in the Kuznetsk basin (Kuzbass) and the Katun river up to Uimonsky (the Altai), intra-mountain drainage basins, the survey of floodplains and eroded banks, and modelling of floods occurring in floodplains. As a result, a concept has been developed to improve protection measures against hazardous hydrological and channel processes. More than 200 engineering and organisational events were suggested as part of the concept. Given the dense network of river banks and the high potential damage caused by floods in Kuzbass, the continuous protection of cities, large residential and commercial areas, as well as sections of roads and railways subject to erosion is a priority in the flood control concept. In the case of the Katun river basin, characterized by local development, low population density, and relatively small damage caused by floods, the emphasis is put on organisational measures: prevention, evacuation of people and property, insurance and compensation. Selective engineering structures should, as a matter of priority, reduce the dangerous erosion of river banks and ensure a high level of protection of the territory against floods
Modeling of Marine Ecosystems: Experience, Modern Approaches, Directions of Development (Review). Part 2. Population and Trophodynamic Models
Purpose. The paper presents the second part of the review of the publications devoted to the problems of marine ecosystem modeling. In this part, major attention is paid to modern approaches to the management of marine biological resources which implement the ecosystem principles of modeling and monitoring the spatiotemporal dynamics of water objects.
Methods and Results. The review consists of three sections. The first one deals with the models for forecasting dynamics of the exploited populations and for optimizing fishery. The second section considers the trophodynamic models used to study the structure, productivity, and functional role of marine biota interacting with other species and environment at various trophic levels. The trophodynamic models are often applied both for assessing the impact of fishery on marine ecosystems, and for analyzing the influence of the factors directly or indirectly related to climatic variability and anthropogenic activity (eutrophication, salinity, environmental changes). The third section of the review is devoted to a relatively recent direction in marine ecosystem modeling which is based on the geo-information systems. The onrush of the geo-information technologies permitting to connect the data both of the field observations and simulations with their geolocation had an impact on the achievements in the field of ecological modeling.
Conclusions. In the coming years, the role of mathematical modeling in study and management of marine ecosystems will grow. The most important areas of research seem to be as follows: perfection of a model description of primary links in the marine ecosystem food webs (NPZD-models); the flows of matter and energy in the marine food chains; eutrophication and oxygen regime in the sea bays; distribution and transformations of pollutants, and their impact on ecosystems; functioning of marine reserves; the means of taking into account climatic factors in the ecosystem models; and application of satellite monitoring data for identifying and verifying the ecosystem individual components (chlorophyll, oil slicks, suspensions)
Evolution and global collapse of trapped Bose condensates under variations of the scattering length
We develop the idea of selectively manipulating the condensate in a trapped
Bose-condensed gas, without perturbing the thermal cloud. The idea is based on
the possibility to modify the mean field interaction between atoms (scattering
length) by nearly resonant incident light or by spatially uniform change of the
trapping magnetic field. For the gas in the Thomas-Fermi regime we find
analytical scaling solutions for the condensate wavefunction evolving under
arbitrary variations of the scattering length . The change of from
positive to negative induces a global collapse of the condensate, and the final
stages of the collapse will be governed by intrinsic decay processes.Comment: 4 pages, LaTeX, other comments are at
http://WWW.amolf.nl/departments/quantumgassen/TITLE.HTM
Diagnostic value of anti-GP2 antibodies determined in serum and coprofiltrates in children with inflammatory bowel disease
Inflammatory bowel diseases (IBD), such as Crohn’s disease (CD) and ulcerative colitis (UC), are characterized by chronically recurring inflammation of intestinal wall and are associated with a significant decrease in the quality of life. A spectrum of genetic variants associated with Crohn’s disease is described. Intestinal dysbiosis (DB) may be the triggering factor of the disease. Glycoprotein 2 (GP2), the main protein of pancreatic zymogen granules, is secreted into the intestines with digestive enzymes. Anti-GP2 antibodies were found in the serum of patients with CD. The aim of the present study was to investigate the levels of anti-GP2 antibodies in serum and feces of children with IBD compared with the DB group. Serums and coprofiltrates from 110 children (64 boys and 46 girls) at the age of 12.3 (2.6-17.9) years were studied; 36 patients with CD, 30 patients with UC. A comparison group consisted of 44 patients with DB. IgG and IgA antibodies against GP2 were tested with ELISA. Nonparametric statistics methods are applied, the results are presented as percentages and medians (Me (Q0.25-Q0.75)). The serum levels of anti-GP2 IgA antibodies were 9.97 (3.35-13.45) U/ml for the CD patients, 6.08 (2.71-14.26) U/ml for UC and 2. 94 (2.29-6.41) U/ml for DB. The levels of anti-GP2 IgG antibodies in serum were 6.16 (3.26-18.4) U/ml for CD, 5.26 (2.97-7.52) U/ml for UC, and for DB 5.23 (2.53-8.85) U/ml. The cut-off threshold concentration for anti-GP2 IgG antibodies was 13.8 U/ml, with sensitivity of 63.2%, specificity 100%, and for IgA 5.63 U/ml, with sensitivity of 60.5% and specificity of 78.8%, thus being lower than the calculated cut-off for adults (20 U/ml). The levels of anti-GP2 IgG in coprofiltrates in children of comparison group were 1.99 (1.26-3.04) U/ml; in the patients with CD, 23.5 (16.15-29.3) U/ml, and in children with UC, 20.45 (13.63-25.5) units/ml (p < 0.001). The cut-off value amounted 8.0 U/ml, with 100% sensitivity and 100% specificity. Concentrations of anti-GP2 IgA in coprofiltrates of patients with IBD did not significantly differ from DB patients. Moreover, the concentration of sIgA in the coprofiltrates of patients with IBD was significantly higher than their level in DB group. The anti-GP2 IgA/sIgA ratio was significantly lower in patients with CD (0.326 (0.23-0.512)), and UC (0.327 (0.205-0.435)), than in patients with DB (2.332 (1.575-3.523)) (p < 0.001); the cut-off level was 0.784, with a sensitivity of 97.7% and specificity of 98.6%. It is discussed, whether fecal anti-GP2 IgA antibodies should be considered as protective, supporting intestinal homeostasis, whereas anti-GP2 IgG antibodies are pathogenetically significant for development of IBD. Thus, using a non-invasive method for determining anti-GP2 antibodies in stool, when exceeding the cut-off for IgG, and reduction of IgA/sIgA ratio below the cut-off, one may differentiate IBD from DB with a similar symptoms at the onset of disease, with 100% sensitivity and 100% specificity
Physical Activity, Life Satisfaction, Stress Perception and Coping Strategies of University Students in Belarus during the COVID-19 Pandemic
The COVID-19 restrictions in Belarus turned out to be less stringent than those of its neighboring countries. Objective: We aimed to evaluate physical activity, life satisfaction, perception of stress, choice of coping strategies and their correlations among Belarusian students. An anonymous Internet survey was conducted among 1769 students studying at the faculties of physical culture (415), pedagogical (737), and medical (617) universities. International Physical Activity Questionnaires (IPAQ) and Satisfaction With Life Scale (SWLS), Perceived Stress Scale-10 (PSS-10), and Coping Orientations to Problems Experienced (mini-COPE) questionnaires were used. The respondents declared sufficient and high levels of physical activity. The level of physical activity was correlated with life satisfaction (typically for student-athletes). The least satisfaction with life and highest level of perceived stress were among future doctors. The minimum indicator of stress was noted in athletes. The most common coping strategy was active coping. Strategies of problem avoidance and
seeking support from outside were not used by student-athletes. These strategies were used by pedagogical and medical students. Student-athletes have the most favorable opportunities, followed by representatives of pedagogical and medical students. The proposed classification of the levels of behavior (optimal, acceptable, satisfactory and risky) makes it possible to adjust lifestyles
Geophysical Observatory in Kamchatka region for monitoring of phenomena connected with seismic activity
Regular monitoring of some geophysical parameters in association with seismicity has been carried out since last year at the Japan-Russian Complex Geophysical Observatory in the Kamchatka region. This observatory was organized in connection with the ISTC project in Russia and was motivated by the results of the FRONTIER/RIKEN and FRONTIER/NASDA research projects in Japan. The main purpose of the observations is to investigate the electromagnetic and acoustic phenomena induced by the lithosphere processes (especially by seismic activity). The seismicity of the Kamchatka area is analyzed and a description of the observatory equipment is presented. At present, the activity of the observatory includes the seismic (frequency range ∆F = 0.5 – 40 Hz) and meteorological recordings, together with seismo-acoustic (∆F = 30 – 1000 Hz) and electromagnetic observations: three-component magnetic ULF variations ( ∆F = 0.003 – 30 Hz), three-component electric potential variations ( ∆F <u><</u> 1.0 Hz), and VLF transmitter’s signal perturbations ( ∆F ~ 10 – 40 kHz)
Identification of the Causes of the Destruction of the Body of the Shut-off Valve
A study was made of the causes of the emergency destruction of the shut-off valve. The fracture surface was studied, the mechanical properties of the material and the structure of the metal were evaluated. The accident was caused by deviations from standard properties and equipment overload
Study of electromagnetic emissions associated with seismic activity in Kamchatka region
International audienceA review of data processing of electromagnetic emission observation collected at the Complex Geophysical Observatory Karimshino (Kamchatka peninsula) during the first 5 months (July?November, 2000) of its operation is given. The main goal of this study addresses the detection of the phenomena associated with Kamchatka seismic activity. The following observations have been conducted at CGO: variations of ULF/ELF magnetic field, geoelectric potentials (telluric currents), and VLF signals from navigation radio transmitters. The methods of data processing of these observations are discussed. The examples of the first experimental results are presented
Prospects for the use of eddy current flaw detectors that are broad zone of control in the repair of pipelines
The questions of choice and optimization of methods of diagnostics of pipes of gas pipelines liable stress are examined in this article - to the corrosive spalling. Practice of diagnostics showed that on short areas at an inspection it is expedient to use the portable fault detectors of type of МВД, ВК on extensive areas the mechanized complexes are justified, for example, ДНС- 1400, and also the vortex-current broad-cut (300 мм) fault detectors of ДНШ- 24 can be used. These fault detectors due to an original construction have the opportunity of easy access a sensor to all control points on the perimeter of pipe, and high-rate of inspection.В данной статье рассматриваются вопросы выбора и оптимизации методов диагностики труб газопроводов, подверженных стресс – коррозионному растрескиванию. Практика диагностики показала, что на коротких участках при обследовании целесообразно использовать портативные дефектоскопы типа МВД, на протяженных участках оправданы механизированные комплексы, например, ДНС-1400, а также могут быть использованы вихретоковые широкозахватные (300 мм) дефектоскопы «ДНШ-24». Эти дефектоскопы за счет оригинальной конструкции имеют возможность легкого доступа датчиком ко всем контрольным точкам по периметру трубы.Работа выполнена в рамках государственного задания ФАНО России по теме «Диагностика», №01201463329
The use of thromboelastography and the functional tests with double local hypoxia of the upper limb to assess the risk of thromboembolism in patients undergoing surgery
Introduction: Prothrombotic is considered a condition that leads to the development of venous or arterial thrombosis and its consequences. There are many factors that cause a violation of the hemostatic potential in patients undergoing surgery with existing risk factors for thromboembolism, a more detailed study of the blood coagulation system, including the study of the compensatory capabilities of the hemocoagulation system, should be conducted. One of these methods is a functional test with double local hypoxia of the upper limb (DLHUL) under the control of thromboelastography (TEG).
Goals: The purpose of the study - to identify the degree of thrombotic risk in patients preparing for planned surgical intervention, who belong to the risk group of thrombotic complications, to compare and evaluate the state of the hemostasis system in healthy volunteers and in this cohort of patients using a functional test with double local hypoxia of the upper limb by the method of thromboelastography.
Materials and methods: A randomized prospective study was conducted. Patients were divided into two groups depending on the presence of risk factors for thrombosis. Group 1 consisted of healthy volunteers (n = 40) who are not at risk of thrombosis. Group 2 includes patients with existing factors of thrombotic risk (n = 120) who are preparing for scheduled surgical interventions. These patients underwent a functional test of "double local hypoxia of the upper limb" (DLHUL) using thromboelastographic (TEG) methods of studying the hemocoagulation system. The main task of this functional test is to create a trigger component to determine the limits of hemostasis, the origin and duration of adaptive and compensatory reactions of the hemostasis system. Indicators of the hemostasis system are recorded using a thromboelastograph before and after the test. The links of hemostasis are reflected by the following indicators: aggregate state of blood (A0), contact coagulation intensity (CCI), coagulation drive intensity (ICD), maximum clot density - maximum activity (MA), fibrinolytic activity - clot retraction and lysis index (IRCL).
The results. Analyzing the data of thromboelastography after performing DLHUL, among the patients of Group 1, two types of reaction of the hemostasis system were found in patients without predictors of thrombotic risk: compensated (n= 20) (characterized by a decrease in the indicators of the vascular-platelet component; subcompensated (n = 20) (characterized by an increase in the indicators of the vascular -platelet component). In subjects of Group 1, TEG indicators indicate an increase in the external mechanism of prothrombinase formation, and the reaction of the procoagulant link of the blood coagulation system in response to the influence of a trigger indicates a change in the directionality of the hemostatic potential towards hypercoagulation. In subjects of group 1 with a compensated type, there is an increase in the components of fibrinolysis and a deviation of the hemostatic potential towards hypocoagulation is observed. The state of the hemostasis system in patients of Group 2 is characterized by pronounced changes in the hemostatic potential in all links. In the vascular-platelet link, a violation of platelet aggregation was noted, with an increase in indicators in response to a stimulus. When conducting the DLHUL test in the subjects of group 2, a decompensated (n = 98) and exhausted (n = 22) type of reaction to the test with local hypoxia of the upper limb was determined. That is, with increased platelet aggregation, hypercoagulation, inhibition of the anticoagulant system and fibrinolysis before the action of the trigger factor, after performing the DLHUL test, these disorders in the hemostasis system progress towards hypercoagulation, which is indicated by the increase in platelet aggregation, the strengthening of the coagulation link of the hemostatic system, the depression of fibrinolysis increases . However, the intensity of these changes is not as high as in patients of group 1 after the DLHUL test.
Conclusions: The test with double local hypoxia of the upper limb is effective as a trigger factor to determine the compensatory capabilities of the HS. Depending on the type of reaction of the platelet-vascular, coagulation components of hemostasis and fibrinolysis to the influence of the trigger, two types of reaction of the blood aggregate state regulation system are possible in people who do not have an anamnesis of factors provoking a hypercoagulable state: compensated and subcompensated. Therefore, when planning surgical intervention in this cohort of patients, the risk of thrombotic complications is low. Depending on the type of reaction of the platelet-vascular, coagulation components of hemostasis and fibrinolysis to the influence of the trigger, two types of reaction of the blood aggregate state regulation system are possible in people with an anamnesis of factors provoking a hypercoagulable state: decompensated (more often) and depleted (less often). Patients with a history of factors provoking a hypercoagulable state have a high risk of perioperative thrombotic complications and a possible risk of thrombo-hemorrhagic complications, including the syndrome of disseminated intravascular coagulation. Changes in all links of the hemostasis system in response to the DLHUL test indicate the need to use anticoagulant therapy in patients with an anamnesis of factors provoking a hypercoagulable state as one of the components of preoperative preparation
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