Peculiarities in plant communities’ formation in crop plantings in the south-eastern part of the Central Russian Upland

The article describes a study of plant communities of the south-western part of the Central Russian Upland that form in batches of various crops. Field studies employed the methods of reconnaissance floristic survey. Species diversity of the plant complexes and plant communities were studied with the morphological-ecological-geographical metho

Nucleophilic Addition of Indoles to Carborancarboxaldehyde – a Convinient Synthetic Strategy Towards Novel Boron-Enriched 3-Indolylmethanols

This work was supported by Russian Science Foundation (Project 18-13-00365)

Выбор схемы программирования мемристорных элементов

Introduction. An array of memristive elements can be used in prospective neural computing systems as a programmable resistance (analog multiplication factor) when performing operations of analog vector multiplication, discrete in time. To form the required resistance, the memristor should be subjected to a programming procedure. This article discusses conventional programming schemes and proposes a new versatile programming scheme for memristor elements.Aim. To identify or develop an optimal programming scheme for memristors by analyzing the advantages and disadvantages of existing methods.Materials and methods. The programming procedure can be carried out using either SET or RESET, depending on a different direction of movement according to the volt-ampere characteristic of the memory and its transfer to a particular state. The programming process is controlled in the LTspice circuit modeling program.Results. Typical programming schemes of memristors were analyzed; advantages and disadvantages of existing methods were revealed. A new versatile circuit based on a variable resistor was proposed. The circuit was simulated both under a fixed resistance of the variable resistor and when varying the memristor resistance values within their permissible range.Conclusion. In comparison with the RESET mode, the SET programming mode provides for a greater linearity of variations in the memristor resistance. The use of a circuit based on a variable resistor and a bipolar voltage source allows programming of any type and eliminates the need for recommutation of the memristor. The simulation results confirm the feasibility of the proposed method. The proposed circuit can be complemented not only with a comparator, but also with an ADC. This will provide the possibility of selecting various means for measuring the memristor resistance both during programming and for the purpose of monitoring the memristor resistance at the end of the procedure.Введение. Массив мемристивных элементов может быть использован в перспективных системах нейровычислений в качестве программируемого сопротивления (аналогового коэффициента умножения) при проведении операций аналогового умножения векторов дискретного по времени. Для формирования требуемого сопротивления мемристор должен быть подвергнут процедуре "программирования". В статье рассматриваются типовые схемы программирования и предлагается новая схема универсального устройства программирования мемристора.Цель работы. Выявить или разработать оптимальную схему программирования мемристоров, анализируя преимущества и недостатки существующих способов.Материалы и методы. Процедура программирования может быть осуществлена двумя способами – SET и RESET, связанными с различным направлением движения по вольт-амперной характеристике мемристора и его переводом в то или иное состояние. Контроль процесса программирования осуществляется в программе схемотехнического моделирования LTspice.Результаты. Проанализированы типовые схемы программирования мемристора, выявлены преимущества и недостатки существующих способов. Предложена новая универсальная схема с использованием переменного резистора. Проведено схемотехническое моделирование при фиксированном значении сопротивления переменного резистора и при вариации разных значений сопротивления в пределах допустимых значений сопротивлений мемристора.Заключение. Режим программирования SET позволяет достичь большей линейности изменения сопротивления мемристора по сравнению с режимом RESET. Применение схемы с использованием переменного резистора и двухполярного источника напряжения позволяет осуществить программирование любого типа и исключает необходимость перекоммутации мемристора. Результаты моделирования подтверждают работоспособность предложенного способа. Дополнительно к наличию компаратора в схему можно ввести и АЦП для возможности выбора средства измерения сопротивления мемристора как в процессе проведения программирования, так и для целей контроля сопротивления мемристора по окончании процедуры

The first search for bosonic super-WIMPs with masses up to 1 MeV/c2^2 with GERDA

We present the first search for bosonic super-WIMPs as keV-scale dark matter candidates performed with the GERDA experiment. GERDA is a neutrinoless double-beta decay experiment which operates high-purity germanium detectors enriched in $^{76}$Ge in an ultra-low background environment at the Laboratori Nazionali del Gran Sasso (LNGS) of INFN in Italy. Searches were performed for pseudoscalar and vector particles in the mass region from 60 keV/c$^2$ to 1 MeV/c$^2$. No evidence for a dark matter signal was observed, and the most stringent constraints on the couplings of super-WIMPs with masses above 120 keV/c$^2$ have been set. As an example, at a mass of 150 keV/c$^2$ the most stringent direct limits on the dimensionless couplings of axion-like particles and dark photons to electrons of $g_{ae} < 3 \cdot 10^{-12}$ and ${\alpha'}/{\alpha} < 6.5 \cdot 10^{-24}$ at 90% credible interval, respectively, were obtained.Comment: 6 pages, 3 figures, submitted to Physical Review Letters, added list of authors, updated ref. [21

Набухание гидрогеля на основе сополимера акриламида и акрилата натрия в водных растворах хлорида меди (II) с добавками аминокислот

Swelling of acrylamide and sodium acrylate copolymer polyelectrolyte hydrogel in aqueous Cu(II) chloride solutions with additives of proteinogenic amino acids glycine and L-histidine has been studied. Research relevance is due to the application of such systems in agrochemical products that are supposed to have high water absorption capacity in the presence of microelements ions and amino acids, which are used to prevent nutritional deficiency and make plants resistant to adverse weather conditions and diseases. Gravimetry, atomic absorption spectrometry, FTIR ATR spectroscopy and molecular absorption spectrophotometry were used. The impact of acidity (pH 3, 5 and 7) of aqueous Cu(II) chloride solutions with amino acids additives on the hydrogel swelling degree and Cu(II) ions absorption has been determined. The reasons for changes in the hydrogel swelling degree in aqueous Cu(II) chloride solutions in presence of glycine and L-histidine have been found. The main product of the crosslinked copolymer interaction with the components of 0.01 M aqueous Cu(II) chloride solution with the addition of 0.04 M glycine or L-histidine at pH 3 has been assumed to be a mixed Cu(II) ions complex with functional groups of both copolymer and amino acids.Изучено набухание полиэлектролитного гидрогеля на основе сополимера акриламида и акрилата натрия в водных растворах хлорида Cu(II) с добавками аминокислот глицина и L-гистидина. Актуальность исследований обусловлена применением таких систем в агрохимических препаратах, которые должны сохранять высокую водоудерживающую способность в присутствии ионов микроэлементов и аминокислот, используемых для устранения дефицита питания и придания растениям устойчивости к неблагоприятным погодным условиям и болезням. Использовали гравиметрический метод анализа, а также атомно-абсорбционную спектрометрию, Фурье-ИК НПВО спектроскопию и молекулярную абсорбционную спектрофотометрию. Определено влияние кислотности (рН 3, 5 и 7) водных растворов хлорида Cu(II) с добавками аминокислот на степень набухания гидрогеля и поглощение им ионов Cu(II). Установлены причины изменения степени набухания гидрогеля в водных растворах хлорида Cu(II) в присутствии глицина и L-гистидина. Высказано предположение, что основным продуктом взаимодействия сшитого сополимера с компонентами 0,01 М водного раствора хлорида Cu(II) с добавкой 0,04 M глицина или L-гистидина при рН 3 является смешанный комплекс ионов Cu(II) с функциональными группами сополимера и аминокислот

Переход ионов меди из пленок на основе гидролизата полиакрилонитрильного волокна в водную фазу

It has been found that copper (II) migration into the aqueous phase from polyacrylonitrile fiber hydrolysate films containing copper sulfate (II) or copper (II) ethylenediaminetetraacetic acid disodium salt, slows down with increased branching of macromolecules. Prolongation effect is more pronounced for copper sulfate (II) due to the formation of copper macromo-lecular complex with carboxylate groups of the copolymer.Установлено, что переход меди(II) в водную фазу из пленок гидролизата полиакрилонитрильного волокна с добавкой сульфата меди(II) или динатриевой соли этилендиаминтетраацетата меди(II) замедляется при увеличении степени разветвления макромолекул. Эффект пролонгации выражен сильнее в случае сульфата меди(II) вследствие формирования макромолекулярного комплекса меди с карбоксилатной группой сополимера

West Nile Fever: Results of Monitoring over the Causative Agent in the Russian Federation in 2021, the Incidence Forecast for 2022

The epidemiological situation on West Nile fever (WNF) in Russia in 2021 was characterized by an increase in the incidence relative to 2020 (more than 6-fold increase). The peculiarities of the WNF epidemic process have been determined: the territorial distribution of cases (75 % – in the constituent entities of the Central Federal District), the expansion of the causative agent’s areal with the involvement of new territories (official registration of cases in Moscow and the Tula Region for the first time ever), the early end of the epidemic season. An increase in the proportion of neuroinvasive forms, an increase in the share of male patients and the age group of 30–39 years, a decrease in the proportion of the population in contact with the pathogen in natural places of mass recreation were observed in the incidence structure. According to the results of the monitoring studies carried out by the Reference Center, intensive circulation of the pathogen was established on the territory of the Central Federal District, Southern Federal District, and the North Caucasian Federal District. The low reported incidence was due to insufficient detection of WNF patients. The results of moleculargenetic study showed that in the European part of Russia, WNV lineage 2 circulated in both epizootic and epidemic cycles, lineage 2 in the south of Western Siberia (Omsk Region) and lineage 4 in the Volgograd Region – in the epizootic cycle only. Phylogenetic analysis revealed that strains isolated from the Astrakhan, Volgograd, Rostov, Voronezh Regions and the Republic of Dagestan in 2021 belong to the genovariant of WNV lineage 2 not registered in Russia previously.  The topology of the phylogenetic tree indicates the possible African origin of the isolates, probably imported into Russia by migratory birds across the coast of the Caspian Sea. In the Volgograd Region, WNV of both the entrenched clade of lineage 2 (since 2007) and new genovariant circulated. The specialists of the Reference Center developed a forecast of WNF epidemiological situation development in the Volgograd Region in 2022 on the basis of the neural network modeling technique, according to which an increase in the incidence is expected, comparable to that in 2010 and 2012. Based on the climate projections, an increase in the incidence is possible in all Federal Districts of the European part of Russia, the southern territories of the Urals, Western Siberia, and the Far East

Influence of metals and metalloids on the composition and fluorescence quenching of the extracellular polymeric substances produced by the polymorphic fungus <i>Aureobasidium pullulans</i>

Aureobasidium pullulansis a ubiquitous and widely distributed fungus in the environment, and exhibits substantial tolerance against toxic metals. However, the interactions between metals and metalloids with the copious extracellular polymeric substances (EPS) produced byA. pullulansand possible relationships to tolerance are not well understood. In this study, it was found that mercury (Hg) and selenium (Se), as selenite, not only significantly inhibited growth ofA. pullulansbut also affected the composition of produced EPS. Lead (Pb) showed little influence on EPS yield or composition. The interactions of EPS fromA. pullulanswith the tested metals and metalloids depended on the specific element and their concentration. Fluorescence intensity measurements of the EPS showed that the presence of metal(loid)s stimulated the production of extracellular tryptophan-like and aromatic protein-like substances. Examination of fluorescence quenching and calculation of binding constants revealed that the fluorescence quenching process for Hg; arsenic (As), as arsenite; and Pb to EPS were mainly governed by static quenching which resulted in the formation of a stable non-fluorescent complexes between the EPS and metal(loid)s. Se showed no significant interaction with the EPS according to fluorescence quenching. These results provide further understanding of the interactions between metals and metalloids and EPS produced by fungi and their contribution to metal(loid) tolerance

Peculiarities of the Epidemic Situation on West Nile Fever in the Territory of the Russian Federation in 2018 and Forecast of its Development in 2019

The epidemic rise in the incidence of West Nile fever (WNF) in the season of 2018 was observed in the countries of the European Union (EU) and bordering states and exceeded the values of all previously recorded epidemic rises of 2010–2012. An increase in the incidence rate was registered in the USA and Canada, however, it did not exceed the indicators of epidemic rises of 2007–2012. In the territory of the Russian Federation, the WNF epidemiological process became more intense mainly in the territory of the Southern and North Caucasian Federal Districts. In general, in Russia, the incidence rates were 2 times lower than the average annual rates, but significantly exceeded those of 2017. The epidemic process had a number of peculiarities in the seasonality, the structure of morbidity and the clinical manifestation of WNF. Genotyping of the isolated WNV RNA fragments from clinical and biological material showed that I, II and IV West Nile virus genotypes were circulating in the European part of Russia. Forecast of epidemic situation development in 2019 reveals further increase in the incidence and does not exclude the possibility of a significant localincrease of WNF incidence in certain regions of Russia

Epizooty of Tularemia, Detected in the Population of the Common Vole in the Natural Focus of Steppe Type in the South-East of the Rostov Region in 2020

The aim of study was to conduct epizootiological monitoring of natural tularemia foci of the steppe type and investigate epizootic activity in the south-east of the Rostov Region.Materials and methods. An epizootiological survey was carried out on the territory of Remontnensky, Sal’sky and Peschanokopsky districts of the Rostov Region in 2019–2021. To capture and collect mammals, Ixodidae ticks and to study the samples of field material conventional methods were used.Results and discussion. Habitation of 16 species of small mammals, 6 species of Ixodidae ticks has been found. Molecular-genetic analysis of the voles has revealed the presence of the species Microtus arvalis obscurus in the studied area of the region. The circulation of the tularemia agent has been established in the population of common and social voles, forest mouse, hare, rook, Dermacentor marginatus, Hyalomma marginatum, removed from rooks. In May 2020, a high increase in the number of the social vole in the Remontnensky district (up to 21 %), in July 2020 – the common vole in the agrocenoses of the Sal’sky district (up to 33 %) was observed. An extensive epizooty of tularemia was detected in the population of common vole in the south-east of the Rostov Region and in adjacent territories in the Republic of Kalmykia and the Stavropol territory. Two cultures of the pathogen were isolated from the fallen and captured social voles, and four cultures – from the common vole. The isolated strains belong to the Holarctic subspecies of Francisella tularensis EryR. The results obtained attest to the activation of the natural tularemia focus in the south-east of the Rostov Region and its high epizootic activity