48 research outputs found

    The CO2_{2} integral emission by the megacity of St Petersburg as quantified from ground-based FTIR measurements combined with dispersion modelling

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    The anthropogenic impact is a major factor of climate change, which is highest in industrial regions and modern megacities. Megacities are a significant source of emissions of various substances into the atmosphere, including CO2_{2} which is the most important anthropogenic greenhouse gas. In 2019 and 2020, the mobile experiment EMME (Emission Monitoring Mobile Experiment) was carried out on the territory of St Petersburg which is the second-largest industrial city in Russia with a population of more than 5 million people. In 2020, several measurement data sets were obtained during the lockdown period caused by the COVID-19 (COronaVIrus Disease of 2019) pandemic. One of the goals of EMME was to evaluate the CO2_{2} emission from the St Petersburg agglomeration. Previously, the CO2_{2} area flux has been obtained from the data of the EMME-2019 experiment using the mass balance approach. The value of the CO2_{2} area flux for St Petersburg has been estimated as being 89Β±28 kt kmβˆ’2^{-2} yrβˆ’1^{-1}, which is 3 times higher than the corresponding value reported in the official municipal inventory. The present study is focused on the derivation of the integral CO2_{2} emission from St Petersburg by coupling the results of the EMME observational campaigns of 2019 and 2020 and the HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectories) model. The ODIAC (Open-Data Inventory for Anthropogenic CO2_{2}) database is used as the source of the a priori information on the CO2_{2} emissions for the territory of St Petersburg. The most important finding of the present study, based on the analysis of two observational campaigns, is a significantly higher CO2_{2} emission from the megacity of St Petersburg compared to the data of municipal inventory, i.e. ∼75800Β±5400 kt yrβˆ’1^{-1} for 2019 and ∼68400Β±7100 kt yrβˆ’1^{-1} for 2020 versus ∼30 000 kt yrβˆ’1^{-1} reported by official inventory. The comparison of the CO2_{2} emissions obtained during the COVID-19 lockdown period in 2020 to the results obtained during the same period of 2019 demonstrated the decrease in emissions of 10 % or 7400 kt yrβˆ’1^{-1}

    Personalizing the Way of Teaching LSP

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    Introduction. The problem of effective teaching language for special purposes (LSP) to the students of non-linguistic professions has been discussed for a long time and in full details by academicians both in Russia and foreign countries. As the result of multiple and thorough surveys general problems of the given situation have been revealed, the way out being defined as special training/retraining of LSP teachers. But in language education publications it is hardly possible to find the description of the program aiming at the training of the above mentioned teachers. The aim of the article is to present effective approaches to teaching LSP and offer the developed master program β€œMethods of teaching LSP” as a means to solve the problems mentioned above. Materials and Methods. The research methods used are a combination of analytical review of studies by Russian and foreign researchers and interpretation of the results obtained by interviewing university teachers specializing in teaching foreign languages to students completing BachelorΚΌs or MasterΚΌs degree programs. The survey was conducted to assess the level of readiness of professional educators to design the structure and content of programs for teaching LSP, and actually conduct classes within the specified language-teaching area, 81 teachers being responders. Results. As a result of the undertaken review of theoretical works and analysis of the conducted survey a master program β€œMethods of teaching LSP” was designed for training graduates who will then teach English or Russian as a foreign language at industry-specific higher schools. The developed program focuses on instructing future LSP educators to work out a personalized educational route adjusted to the level of foreign language skills of a student and their prospective professional activities. Discussion and Conclusion. The master program developed by the authors as well as the content of the subjects suggested as its integral part are expected to become a productive way of training LSP educators who are supposed to acquire a number of special skills and competences described in the article. Distant learning and e-learning technologies are also engaged in the program to facilitate learners’ more efficient independent activities. The master program is seen as one of the means of modernizing LSP teachers’ professional training which meets the long-term needs of the Russian education system

    Discovery of extremely halophilic, methyl-reducing euryarchaea provides insights into the evolutionary origin of methanogenesis

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    Methanogenic archaea are major players in the global carbon cycle and in the biotechnology of anaerobic digestion. The phylum Euryarchaeota includes diverse groups of methanogens that are interspersed with non-methanogenic lineages. So far, methanogens inhabiting hypersaline environments have been identified only within the order Methanosarcinales. We report the discovery of a deep phylogenetic lineage of extremophilic methanogens in hypersaline lakes and present analysis of two nearly complete genomes from this group. Within the phylum Euryarchaeota, these isolates form a separate, class-level lineage 'Methanonatronarchaeia' that is most closely related to the class Halobacteria. Similar to the Halobacteria, 'Methanonatronarchaeia' are extremely halophilic and do not accumulate organic osmoprotectants. The high intracellular concentration of potassium implies that 'Methanonatronarchaeia' employ the 'salt-in' osmoprotection strategy. These methanogens are heterotrophic methyl-reducers that use C 1 -methylated compounds as electron acceptors and formate or hydrogen as electron donors. The genomes contain an incomplete and apparently inactivated set of genes encoding the upper branch of methyl group oxidation to CO2 as well as membrane-bound heterodisulfide reductase and cytochromes. These features differentiate 'Methanonatronarchaeia' from all known methyl-reducing methanogens. The discovery of extremely halophilic, methyl-reducing methanogens related to haloarchaea provides insights into the origin of methanogenesis and shows that the strategies employed by methanogens to thrive in salt-saturating conditions are not limited to the classical methylotrophic pathway.Accepted Author ManuscriptBT/Environmental Biotechnolog

    Investigation of spaceborne trace gas products over St Petersburg and Yekaterinburg, Russia, by using COllaborative Column Carbon Observing Network (COCCON) observations

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    This work employs ground- and space-based observations, together with model data, to study columnar abundances of atmospheric trace gases (XH2_2O, XCO2_2, XCH4_4 and XCO) in two high-latitude Russian cities, St. Petersburg and Yekaterinburg. Two portable COllaborative Column Carbon Observing Network (COCCON) spectrometers were used for continuous measurements at these locations during 2019 and 2020. Additionally, a subset of data of special interest (a strong gradient in XCH4 and XCO was detected) collected in the framework of a mobile city campaign performed in 2019 using both instruments is investigated. All studied satellite products (TROPOMI, OCO-2, GOSAT, MUSICA IASI) show generally good agreement with COCCON observations. Satellite and ground-based observations at high latitudes are much sparser than at low or mid latitudes, which makes direct coincident comparisons between remote-sensing observations more difficult. Therefore, a method of scaling continuous Copernicus Atmosphere Monitoring Service (CAMS) model data to the ground-based observations is developed and used for creating virtual COCCON observations. These adjusted CAMS data are then used for satellite validation, showing good agreement in both Peterhof and Yekaterinburg. The gradients between the two study sites (Ξ”Xgas) are similar between CAMS and CAMS-COCCON datasets, indicating that the model gradients are in agreement with the gradients observed by COCCON. This is further supported by a few simultaneous COCCON and satellite Ξ”Xgas measurements, which also agree with the model gradient. With respect to the city campaign observations recorded in St Petersburg, the downwind COCCON station measured obvious enhancements for both XCH4_4 (10.6 ppb) and XCO (9.5 ppb), which is nicely reflected by TROPOMI observations, which detect city-scale gradients of the order 9.4 ppb for XCH4_4 and 12.5 ppb for XCO

    Emission Monitoring Mobile Experiment (EMME): An overview and first results of the St. Petersburg megacity campaign 2019

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    Global climate change is one of the most important scientific, societal and economic contemporary challenges. Fundamental understanding of the major processes driving climate change is the key problem which is to be solved not only on a global but also on a regional scale. The accuracy of regional climate modelling depends on a number of factors. One of these factors is the adequate and comprehensive information on the anthropogenic impact which is highest in industrial regions and areas with dense population – modern megacities. Megacities are not only β€œheat islands”, but also significant sources of emissions of various substances into the atmosphere, including greenhouse and reactive gases. In 2019, the mobile experiment EMME (Emission Monitoring Mobile Experiment) was conducted within the St. Petersburg agglomeration (Russia) aiming to estimate the emission intensity of greenhouse (CO2_{2}, CH4_{4}) nd reactive (CO, NOx_{x}) gases for St. Petersburg, which is the largest northern megacity. St. Petersburg State University (Russia), Karlsruhe Institute of Technology (Germany) and the University of Bremen (Germany) jointly ran this experiment. The core instruments of the campaign were two portable Bruker EM27/SUN Fourier transform infrared (FTIR) spectrometers which were used for ground-based remote sensing measurements of the total column amount of CO2_{2}, CH4_{4} and CO at upwind and downwind locations on opposite sides of the city. The NO2_{2} tropospheric column amount was observed along a circular highway around the city by continuous mobile measurements of scattered solar visible radiation with an OceanOptics HR4000 spectrometer using the differential optical absorption spectroscopy (DOAS) technique. Simultaneously, air samples were collected in air bags for subsequent laboratory analysis. The air samples were taken at the locations of FTIR observations at the ground level and also at altitudes of about 100 m when air bags were lifted by a kite (in case of suitable landscape and favourable wind conditions). The entire campaign consisted of 11 mostly cloudless days of measurements in March–April 2019. Planning of measurements for each day included the determination of optimal location for FTIR spectrometers based on weather forecasts, combined with the numerical modelling of the pollution transport in the megacity area. The real-time corrections of the FTIR operation sites were performed depending on the actual evolution of the megacity NOx_{x} plume as detected by the mobile DOAS observations. The estimates of the St. Petersburg emission intensities for the considered greenhouse and reactive gases were obtained by coupling a box model and the results of the EMME observational campaign using the mass balance approach. The CO2_{2} emission flux for St. Petersburg as an area source was estimated to be 89 ± 28 ktkmβˆ’2^{-2} yr βˆ’2^{-2} , which is 2 times higher than the corresponding value in the EDGAR database. The experiment revealed the CH4_{4} emission flux of 135 ± 68 tkm βˆ’2^{-2} yr βˆ’1^{-1}, which is about 1 order of magnitude greater than the value reported by the official inventories of St. Petersburg emissions (βˆΌβ€‰25 tkmβˆ’2^{-2} yr βˆ’1^{-1} or 2017). At the same time, for the urban territory of St. Petersburg, both the EMME experiment and the official inventories for 2017 give similar results for the CO anthropogenic flux (251 ± 104 tkm βˆ’2^{-2} yr βˆ’1^{-1} s. 410 tkm βˆ’2^{-2} yr βˆ’1^{-1}) nd for the NOx_{x} anthropogenic flux (66 ± 28 tkmβˆ’2^{-2} yr βˆ’1^{-1} vs. 69 tkm βˆ’2^{-2} yr βˆ’1^{-1})

    Survival, cognitive functions, and brain MRI in patients with cSVD: 5-year observation

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    Introduction. Contributing to high disability and mortality, cerebral small vessel disease (cSVD) is a common condition in senior and elderly individuals. Objective: to assess the 5-year survival as well as cognitive and MRI changes in patients with cSVD and cognitive impairment (CI). Materials and methods. A prospective 5-year study included 54 patients (of them 37 women; mean age: 60.51 6.76 years) with cSVD, CIs, and white matter hyperintensities (WMHs; Fazekas 23). Twenty-two subjects were followed up to assess cognitive functions and a type of CI, cSVD MRI features, WMH, white and grey matter, and cerebrospinal fluid (CSF) volume as well as microstructural brain changes and correlate cognitive and MRI parameters at 5 years timepoint after the baseline. Results. Dementia developed in 14% of the subjects and 14% of the subjects died over a 5-year period. The subjects assessed twice had controlled hypertension (HTN). CIs worsened in the domain of executive functions and memory with mixed-type CI worsening. The follow-up showed that the WMH and CSF volume increased while the white matter volume decreased and axial diffusivity increased in the corpus callosum. The CSF volume correlated with the Stroop Test results and delayed memory (r = 0.803 and r = 0.701, respectively) and with white matter atrophy (r = 0.256) while the latter correlated with the axial diffusivity increased in the corpus callosum (r = 0.560). Conclusion. cSVD with advanced WMHs is associated with high mortality and dementia progression. General cognition assessment and MRI scan are not enough sensitive to assess disorder progression over a 5-year period. Stroop Test and Delayed 10-Word Recall Test results and transition to mixed-type CI indicate CI worsening and, therefore, can be used for the follow-up assessment. Cognitive decline in extensive cSVD is mediated by the brain matter atrophy and altered CSF circulation

    Discovery of anaerobic lithoheterotrophic haloarchaea, ubiquitous in hypersaline habitats

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    Hypersaline anoxic habitats harbour numerous novel uncultured archaea whose metabolic and ecological roles remain to be elucidated. Until recently, it was believed that energy generation via dissimilatory reduction of sulfur compounds is not functional at salt saturation conditions. Recent discovery of the strictly anaerobic acetotrophic Halanaeroarchaeum compels to change both this assumption and the traditional view on haloarchaea as aerobic heterotrophs. Here we report on isolation and characterization of a novel group of strictly anaerobic lithoheterotrophic haloarchaea, which we propose to classify as a new genus Halodesulfurarchaeum. Members of this previously unknown physiological group are capable of utilising formate or hydrogen as electron donors and elemental sulfur, thiosulfate or dimethylsulfoxide as electron acceptors. Using genome-wide proteomic analysis we have detected the full set of enzymes required for anaerobic respiration and analysed their substrate-specific expression. Such advanced metabolic plasticity and type of respiration, never seen before in haloarchaea, empower the wide distribution of Halodesulfurarchaeum in hypersaline inland lakes, solar salterns, lagoons and deep submarine anoxic brines. The discovery of this novel functional group of sulfur-respiring haloarchaea strengthens the evidence of their possible role in biogeochemical sulfur cycling linked to the terminal anaerobic carbon mineralisation in so far overlooked hypersaline anoxic habitats.</p

    Validation of methane and carbon monoxide from Sentinel-5 Precursor using TCCON and NDACC-IRWG stations

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    The Sentinel-5 Precursor (S5P) mission with the TROPOspheric Monitoring Instrument (TROPOMI) on board has been measuring solar radiation backscattered by the Earth\u27s atmosphere and surface since its launch on 13 October 2017. In this paper, we present for the first time the S5P operational methane (CH4) and carbon monoxide (CO) products\u27 validation results covering a period of about 3 years using global Total Carbon Column Observing Network (TCCON) and Infrared Working Group of the Network for the Detection of Atmospheric Composition Change (NDACC-IRWG) network data, accounting for a priori alignment and smoothing uncertainties in the validation, and testing the sensitivity of validation results towards the application of advanced co-location criteria. We found that the S5P standard and bias-corrected CH4 data over land surface for the recommended quality filtering fulfil the mission requirements. The systematic difference of the bias-corrected total column-averaged dry air mole fraction of methane (XCH4) data with respect to TCCON data is βˆ’0.26Β±0.56 % in comparison to βˆ’0.68Β±0.74 % for the standard XCH4 data, with a correlation of 0.6 for most stations. The bias shows a seasonal dependence. We found that the S5P CO data over all surfaces for the recommended quality filtering generally fulfil the missions requirements, with a few exceptions, which are mostly due to co-location mismatches and limited availability of data. The systematic difference between the S5P total column-averaged dry air mole fraction of carbon monoxide (XCO) and the TCCON data is on average 9.22Β±3.45 % (standard TCCON XCO) and 2.45Β±3.38 % (unscaled TCCON XCO). We found that the systematic difference between the S5P CO column and NDACC CO column (excluding two outlier stations) is on average 6.5Β±3.54 %. We found a correlation of above 0.9 for most TCCON and NDACC stations. The study shows the high quality of S5P CH4 and CO data by validating the products against reference global TCCON and NDACC stations covering a wide range of latitudinal bands, atmospheric conditions and surface conditions

    The Bifidobacterium dentium Bd1 Genome Sequence Reflects Its Genetic Adaptation to the Human Oral Cavity

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    Bifidobacteria, one of the relatively dominant components of the human intestinal microbiota, are considered one of the key groups of beneficial intestinal bacteria (probiotic bacteria). However, in addition to health-promoting taxa, the genus Bifidobacterium also includes Bifidobacterium dentium, an opportunistic cariogenic pathogen. The genetic basis for the ability of B. dentium to survive in the oral cavity and contribute to caries development is not understood. The genome of B. dentium Bd1, a strain isolated from dental caries, was sequenced to completion to uncover a single circular 2,636,368 base pair chromosome with 2,143 predicted open reading frames. Annotation of the genome sequence revealed multiple ways in which B. dentium has adapted to the oral environment through specialized nutrient acquisition, defences against antimicrobials, and gene products that increase fitness and competitiveness within the oral niche. B. dentium Bd1 was shown to metabolize a wide variety of carbohydrates, consistent with genome-based predictions, while colonization and persistence factors implicated in tissue adhesion, acid tolerance, and the metabolism of human saliva-derived compounds were also identified. Global transcriptome analysis demonstrated that many of the genes encoding these predicted traits are highly expressed under relevant physiological conditions. This is the first report to identify, through various genomic approaches, specific genetic adaptations of a Bifidobacterium taxon, Bifidobacterium dentium Bd1, to a lifestyle as a cariogenic microorganism in the oral cavity. In silico analysis and comparative genomic hybridization experiments clearly reveal a high level of genome conservation among various B. dentium strains. The data indicate that the genome of this opportunistic cariogen has evolved through a very limited number of horizontal gene acquisition events, highlighting the narrow boundaries that separate commensals from opportunistic pathogens

    Mitochondrial physiology

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    As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery
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