28 research outputs found
Carbon outflow from the active layer of thermokarst lake catchments in the Lena River delta
Nowadays due to climate change the interest to the hydrological processes in the permafrost affected regions is growing. Permafrost soil is important carbon pool and thawing can cause the increase of carbon outflow from Arctic river basins. During Russian-German expeditions Lena-2012 and 2013 some measurements were carried out on the catchment of the Fish Lake on Samoylovsky Island in the Lena River delta. Fish Lake is a thermokarstpolygonal lake, and the landscape of its catchment is typical for the Arctic polygonal tundra. These measurements were done in order to study the DOC income to the lake from an active layer of the catchment. Measurements of the DOC concentration in the pore water and the depth of seasonal thawing were made at 21 points in the 1,52 sq km catchment. The points were selected in different parts of the polygons to consider the heterogeneity of the landscape. Samples for DOC were analyzed in the field using a Spectro::lyser probe and in the lab with a Shimadzu TOC-L probe. In August the depth of the active layer was between 20 and 60 cm: 20-30 cm on the polygon rims, 30-60 cm in the polygon centers and near the lake. During the month when the measurements were made the depth increased by 10-15. For August the DOC concentration in the pore water of the active layer was 8-51 mg/l, for July – 5-30 mg/l, which correlates with the results of other researches in Arctic region. The changes in DOC concentration in pore water for the different thaw depth were examined. Maximum was observed on the depth 35-40 cm for July and 45-55 cm for August. So, for the same depth the variance in the concentration was the most significant. The DOC flux to the Fish Lake was calculated using the mean measured concentration and water runoff from the catchment (Ogorodnikova, 2011). The DOC daily flux to the lake is evaluated as about 0,8 kg per day and the flow rate is 0,5 kg/ km2*day, which is in ten time less than for the lake catchment of southern areas (Moore, 2003). Prolongation of field measurements is necessary for reasons clarifying and for better understanding of DOC flux formation processes under different conditions including thawing increase
Hydro-geochemical characteristics and transformation processes of the Lena River Delta branches
Previous studies have shown that arctic river delta systems are areas of accumulation of geochemical substances at the sea-river mixing zone. In the Lena River Delta our previous work shows the tendencies of water runoff redistribution changes and heterogeneity of suspended supply distribution along the delta branches, accumulation and erosion zone in the different parts of the delta. Nevertheless, the processes of geochemical flow transformation in the subaerial deltas are so far underestimated. In order to close this gap, we sampled water, suspended and bottom sediments in the Lena River Delta in the summer seasons of 2010 and 2014. Most of the sampling points were tight to the profiles of hydrological measurements held in the delta and highlighted in Fedorova et al. [2015]. The results show that geochemical transformation of the Lena River runoff is taking place in the delta. The most active time for the transformation is the summer season due to the activity of sediment accumulation and biogeochemical processes. Hydrological conditions in the delta affect also its hydrogeochemical characteristics. Furcation of the delta branches affects the hydrodynamic conditions of different delta areas. The factors influencing the geochemical characteristics of the delta were identified on the base of geochemical indexes approach applied to sediments and statistical factor analysis. Based on geochemical indexes (Al/Na, Si/Al, Fe/Mn and Fe/Al ratios) similar conditions were determined for the main branch of the Lena, the upstream parts of Bykovskaya and Tumatskaya branches and in Olenekskaya branch near Chay-Tumus. Despite of high runoff the branches are characterized by element accumulation, which can be explained by decreasing of flow turbulence and specificity redox conditions in these areas. Bottom sediments are one of the most important indicators of geochemical transformation processes. The results of statistical factor analysis show three main factors for formation of the these geochemical conditions in the delta: 1. the general water flow of the Lena River, which is influenced by the lithogenous base of the river catchment, 2. the cryogenic condition of the Lena Delta (permafrost degradation processes and cryogenic weathering) and 3. biogeochemical transformation during redistribution of chemical water components , suspended matter and bottom sediments.
Acknowledgements
The research was supported by grant No. 14-05-00787 A of Russian Foundation for Basic Research
References
Fedorova, I.; Chetverova, A.; Bolshiyanov, D.; Makarov, A.; Boike, J.; Heim, B.; Morgenstern,
A.; Overduin, P. P.; Wegner, C.; Kashina, V.; Eulenburg, A.; Dobrotina, E. and Sidorina, I. [2015]: Lena Delta hydrology and geochemistry: long-term hydrological data and recent field observations. Biogeosciences, 12(2):345–363, doi:10.5194/bg-12-345-2015
The management of acute myocardial infarction in the Russian Federation: Protocol for a study of patient pathways [version 2; referees: 2 approved]
Source at https://doi.org/10.12688/wellcomeopenres.12478.2. Background: Death rates from cardiovascular disease in Russia are among the highest in the world. In recent years, the Russian government has invested substantially in the healthcare system, with a particular focus on improving access to advanced technology, especially for acute myocardial infarction (AMI). This protocol describes a study to understand the management of AMI in different Russian regions, investigating the role of patient, clinical, and health system characteristics.
Methods: A prospective observational study has recruited a representative sample of AMI patients within 16 hospitals from 13 regions across Russia. Criteria for inclusion are being aged 35-70 years with a confirmed diagnosis of AMI and surviving until the day after admission. Information being collected includes health system contacts and features of clinical management prior to the event and in the 12 months following discharge from hospital. Following initial exploration of the data to generate hypotheses, multivariate analyses will be applied to assess the role of these characteristics in both treatment decisions and any delays in time critical interventions. Between June 2015 and August 2016, 1,122 patients have been recruited at baseline and follow-up to 12 months post-discharge is scheduled to be completed by autumn 2017. The study is unique in examining patient factors, clinical management prior to admission and in hospital in the acute phase and throughout the critical first year of recovery across a diverse range of geographies and facilities. It uses standardized instruments to collect data from patients and health care providers and includes regions that are diverse in terms of geography and development of cardiology capacity. However, given the limited health services research capacity in the Russian Federation, it was not possible to obtain a sample that was truly nationally representative
Spatial-temporal coherence of different scale hydrological processes in the Lena River delta
The Lena River delta is one of the hydrologically entertaining objects. Hundreds channels and thousands lakes as well as thawing ice complex and permafrost active layer dynamic allow to investigate spatial-temporal coherence of different scale hydrological processes. During 15 years Russian-German scientific collaboration on hydrological, hydrochemical and hydrobiological studies have been operated on different water objects for cause-effect relation of large and specific micro processes indication. Transient liquid-frozen water phase change is significant not only for active layer runoff forming but also for hydrochemical and biological specific. Thus, maximum of DOC is in the overlaying soil layer than permafrost border [Bobrova et al., 2013]. It could be used for modeling of runoff forming and biological activity estimation. Measured temperature of lacustrine bottom sediment of one thermokarst lake on Samoylov Island shows maximal volume 3,7 °C on 1,75 cm beneath water-sediment border [Skorospekhova, 2015]. It is also can be interpreted as biological processes activity, for example, organic material destruction with additional heating. It could be observed more detail and can be used for modeling of a lake thermic regime. Hydrobiological specificity shows similarity of species in the channels and lakes, poorness of biodiversity, especially in big channel; only stagnant in summer season Bulkurskaya channel has more zooplankton species in four times than the main river channel [Nigamatzyanova et al., 2015]. Decline of water turbidity from the delta top to channel edges is about 5-8 times [Charkin et al., 2009]. Considerable turbidity increase is formed according to permafrost thawing and can reach 500 g l-1 including high concentration of carbon and biogenic elements. Thermokarst lake degradation [Morgenstern et al., 2011] plays also an important role for permafrost hydrology in the delta. Outflow from an ice complex forms a high local suspended supply in adjacent river branches and influences on biological processes consequently [Dubinenkov et al., 2015]. Underestimated effect of water and sediment discharge increase in the middle part of river branches had been marked [Fedorova et al., 2015]. Head flux of the large Lena River forms taliks under channels with more sophisticated affect in the shoreline zone of the
Laptev Sea due to aquifer dynamic and mixing of fresh and salt water. Talik effect on hydrology and sedimentation (and suspended material transformation) in the central part of the delta is currently carried out according to geophysical and hydrogeological methods. First field measurements are planned to be done in April 2016 and results will be presented in the ICOP 2016. The studies have been done with support of RFBR grant 14-05-00787 and 15-35-50949, in the framework of Russian-German projects “ CarboPerm” and “Scientific station “Samoylov Island”. The project for both SPBU and DFG funding had also applied for field and scientific investigation as well.
References
Bobrova, O.; Fedorova, I.; Chetverova, A.; Runkle, B. and Potapova, T. Input of Dissolved Organic Carbon for Typical Lakes in Tundra Based on Field Data of the Expedition Lena–2012. In Proceedings of the 19th International Northern Research Basins Symposium and Workshop, Southcentral Alaska, USA – August 11–17, 2013, 2013.
Charkin, A.N.; Dudarev, O.V.; Semiletov, I.P.; Fedorova, I.; Chetverova, A.A.; J., Vonk; Sanchez- Garcia, L.; Gustafsson, ö. and Andersson, P. edimentation in the System of the Delta Lena River - the South Western Part of Buor-Haya Gulf (the Laptev Sea). In The 16th International Symposium on Polar Sciences. Incheon, Korea. 2009, 2009.
Dubinenkov, I.; Flerus, R.; Schmitt-Kopplin, P.; Kattner, G. and Koch, B.P. [2015]: Origin-specific molecular signatures of dissolved organic matter in the Lena Delta. Biogeochemistry, 123(1):1–14, doi:10.1007/s10533-014-0049-0.
Fedorova, I.; Chetverova, A.; Bolshiyanov, D.; Makarov, A.; Boike, J.; Heim, B.; Morgenstern,
A.; Overduin, P. P.; Wegner, C.; Kashina, V.; Eulenburg, A.; Dobrotina, E. and Sidorina, I. [2015]: Lena delta hydrology and geochemistry: long-term hydrological data and recent field observations. Biogeosciences, 12(2):345–363, doi:10.5194/bg-12-345-2015.
Morgenstern, A.; Grosse, G.; Günther, F.; Fedorova, I. and Schirrmeister, L. [2011]: Spatial analyses of thermokarst lakes and basins in Yedoma landscapes of the Lena Delta. The Cryosphere, 5(4):849–867, doi:10.5194/tc-5-849-2011.
Nigamatzyanova, G.; Frolova, L.; Chetverova, A. and Fedorova, I. Hydrobiological investigation of branches of the Lena River edge zone. In Uchenye Zapiski Kazanskogo Universiteta, Seriya Estestvennye Nauki. 2015. in Russian.
Skorospekhova, T. Report of a spring campaign of the expedition “Lena 2015”. AARI’s library stock, 2015
Contribution of permafrost degradation landforms to summer export of DOC from Yedoma-type Ice Complex
Thermo-erosional landforms (valleys, gullies) and
their associated streams are the main connecting pathways
between inland permafrost areas and rivers and
coasts. Surface and ground waters are routed along
these streams, which transport particulate and dissolved
matter from the catchments to the rivers and
coastal waters. Regions of ice-rich permafrost, such
as the Yedoma-type Ice Complex, are not only characterized
by a high abundance of thermo-erosional
landforms, which formed during the Holocene, but are
subject to extensive degradation under current arctic
warming by processes such as thermal erosion, thermokarst,
and active layer deepening. In the Siberian
Lena River Delta Yedoma-type Ice Complex deposits
occur on insular remnants of a Late-Pleistocene
accumulation plain that has been dissected by Lena
River branches and degraded by thermal erosion and
thermokarst during the Holocene. This region serves
as suitable exemplary study area for estimating the
contribution of 1) different permafrost degradation
landforms to the export of water and dissolved matter
from Yedoma-type Ice Complex to the river and 2)
active degradation of old permafrost versus seasonal
runoff from the surface and active layer. In the summers
of 2013 and 2014 we sampled surface and soil
waters from streams and their watersheds in Yedomatype
Ice Complex landscapes of the Lena River Delta
and analyzed them for a range of hydrogeochemical
parameters including electrical conductivity (EC), dissolved
organic carbon (DOC) and stable isotopic composition.\ud
The sampling sites were spread over an
E-W-extent of about 150 km and are characterized
by very diverse geomorphological and hydrological
situations in terms of distance to the river branches,
catchment size, discharge, degree of thermo-erosional
activity, and connection to other permafrost degradation
landforms (thermokarst lakes and basins). Three
key sites were sampled three and four times from June
to September 2013 and 2014, respectively, in order to
analyze intra-seasonal changes.
The results show large variances in EC (25 to 1205
μS/cm), DOC concentrations (2.9 to 119.0 mg/l),
�18O (-29.8 to -14.6 ‰ vs. SMOW), and �D (-228.9
to -117.9‰ vs. SMOW) over the whole dataset, with
distinct characteristics in the parameter combination
for different degradation landform and water types.
The temporal variability at the repeatedly sampled
sites is low, which implies that there is not much
change in the processes that determine the water
composition throughout the summer season. By comparing
differences in surface water chemistry between
flow path systems that tap into varying amounts of
source water (precipitation, surface and ground water,
ground ice) and have differing residence times and
extents, we explore the effect of future changes in thermokarst
and thermo-erosional intensity and resulting
changes in flow path hydrogeochemistry for thermoerosional
features draining ice-rich permafrost
HIV Disclosure, Condom Use, and Awareness of HIV Infection Among HIV-Positive, Heterosexual Drug Injectors in St. Petersburg, Russian Federation
We examined the prevalence of HIV disclosure to sexual partners by HIV-positive drug injectors (IDUs) in St. Petersburg, Russia and compared the magnitude and direction of associations of condom use with awareness of one’s HIV infection and disclosure to partners. Among 157 HIV-infected participants, awareness of infection at time of last intercourse was associated with condom use with partners perceived to be HIV-negative (aOR 6.68, 95% CI 1.60–27.88). Among the 70 participants aware of their infection prior to enrolment, disclosure to potentially uninfected sexual partners was independently and negatively associated with condom use (aOR 0.13, 95% CI 0.02–0.66). Disclosure was independently associated with having injected ≥9 years (aOR 6.04, 95% CI 1.53–23.77) and partnership with another IDU (aOR 3.61, 95% CI 1.44–9.06) or HIV-seropositive (aOR 45.12, 95% CI 2.79–730.46). Scaling up HIV testing services and interventions that increase the likelihood of individuals receiving their test results is recommended
Vyhodnoceni asociaci genetickych markeru s uzitkovosti v komercni populaci prasat.
The aim of this thesis was to analyse possible associations between candidate gene of fertility (ESR2 gene), meat efficiency (IGF2, CM and myogenin genes) and mainly characters of fertility and meat efficiency in pigs. The genotypes of the ESR2 gene were detected in 328 sows of the Large White breed. The traits of fertility (total number of born, number of born alive and number of weaned piglets) and others traits of efficiency (number of teats, back fat thickness, average daily gain) were observed. The influence of myogenin, IGF2 and CM genes polymorphisms on meat efficiency in the population of 118 Large White pigs was analysed.Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi
Priority areas formation of speech competence students of non-philological specialties
The article analyzes the current trends and conditions for the development of students 'speech-thinking abilities and the formation of students' speech competence, and examines modern methods used in the classroom to improve the speech culture of future specialists. The data of the ascertaining experiment showing the level of development of speech competence of students are given. Criteria and factors of speech formation are considered. It is emphasized that the leading principle of educational process management is the formation of motivational factors and reflection of students in terms of the quality of their speech. Promising technologies for the formation of speech competence of specialists are identified. The main direction of development of speech competence of students at the present stage is the formation of speech culture based on linguistic, cultural, situational, professional levels; taking into account the psychological characteristics of specialists, factors of motivation and reflection of students. The leading methods of speech training are teaching methods that correspond to a person-oriented technology, problem tasks (search-game, cognitive-search, role-playing games, discussions), language exercises, emotional-behavioral tasks, and others)