140 research outputs found

    Soil formation in technogenic landscapes: trends, results, and representation in the current classifications (Review)

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    For hundreds of years, humans have been a soil formation factor. With the recent industrial development of vast territories, the formation of soils in technogenic and postanthropogenic conditions requires more attention. This study reviews the literature on the soils of human-transformed or human-made landscapes (technogenic landscapes),in which soil formation starts on a new technogenic substrate. Such soils may occur in different bioclimatic conditions. We focused on processes that govern soil morphology and the subsequent transformation of these soils. Often, the soils of technogenic landscapes are characterized by high bulk density values and by the presence of dense contact. Their properties are affected mainly by organic matter accumulation (humus, litter, and peat). The paper also covers approaches to the reclamation of technogenic landscapes, the main stages, and partly the reclamation options. It is noted that the efficiency of reclamation activities depends on the available resources and timely decision-making. We assessed the efficiency of soil reclamation methods and suggested technogenic landscape survey techniques. The major approaches to soil classification in technogenic landscapes in national and international soil classification systems are briefly discussed, and an approximate correlation of soil names used in different systems is suggested. All considered classifications provide the opportunity to assess the soil properties and specifics of soil formation in technogenic landscapes. However, in most studies, the soil diagnostics are limited to top-order taxa only

    Resonant Inversion of Tunneling Magnetoresistance

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    Resonant tunneling via localized states in the barrier can invert magnetoresistance in magnetic tunnel junctions. Experiments performed on electrodeposited Ni/NiO/Co nanojunctions of area smaller than 0.01 μm2 show that both positive and negative values of magnetoresistance are possible. Calculations based on Landauer-Bu¨ttiker theory explain this behavior in terms of disorder-driven statistical variations in magnetoresistance with a finite probability of inversion due to resonant tunneling

    Consolidating Russia and Eurasia Antibiotic Resistance Data for 1992–2014 Using Search Engine

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    Background: The World Health Organization recognizes the antibiotic resistance problem as a major health threat in the 21st century. The paper describes an effort to fight it undertaken at the verge of two industries - healthcare and Data Science. One of the major difficulties in monitoring antibiotic resistance is low availability of comprehensive research data. Our aim is to develop a nation-wide antibiotic resistance database using Internet search and data processing algorithms using Russian language publications. Materials and methods: An interdisciplinary team built an intelligent Internet search filter to locate all publicly available research data on antibiotic resistance in Russia and Eurasia countries, extracted it, and collated it for analysis. A database was constructed using data from 850 original studies conducted at 153 locations in 12 countries between 1992 and 2014. The studies contained susceptibility and resistance rates of 156 microorganisms to 157 antibiotic drugs. Results: The applied search methodology was highly robust in that it yielded search precision of 58% versus 20% in a typical Internet search. It allowed finding and collating within the database the following data items (among many others): publication details including title, source, date, authors, etc.; study details: time period, locations, research organization, therapy area, etc.; microorganisms and antibiotic drugs included in the study along with prevalence values of resistant and susceptible strains, and numbers of isolates.The next stage in project development will try to validate the data by matching it to major benchmark studies; in addition, a panel of experts will be convened to evaluate the outcomes.Conclusions: The work provides a supplementary tool to national surveillance systems in antibiotic resistance, and consolidates fragmented research data available for 12 countries for a period of more than 20 years

    Quantized magnetoresistance in atomic-size contacts

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    When the dimensions of a metallic conductor are reduced so that they become comparable to the de Broglie wavelengths of the conduction electrons, the absence of scattering results in ballistic electron transport and the conductance becomes quantized. In ferromagnetic metals, the spin angular momentum of the electrons results in spin-dependent conductance quantization and various unusual magnetoresistive phenomena. Theorists have predicted a related phenomenon known as ballistic anisotropic magnetoresistance (BAMR). Here we report the first experimental evidence for BAMR by observing a stepwise variation in the ballistic conductance of cobalt nanocontacts as the direction of an applied magnetic field is varied. Our results show that BAMR can be positive and negative, and exhibits symmetric and asymmetric angular dependences, consistent with theoretical predictions. Includes supplemental figures 1-4

    Continuing to reflect on TLS 1.3 with external PSK

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    The TLS protocol is the main cryptographic protocol of the Internet. The work on its current version, TLS 1.3, was completed in 2018. This version differs from the previous ones and has been developed taking into account all modern principles of constructing cryptographic protocols. At the same time, even when there are security proofs in some fairly strong security model, it is important to study the possibility of extending this model and then clarifying the security limits of the protocol. In this paper, we consider in detail the restriction on the usage of post-handshake authentication in connections established on external PSK. We clarify that the certain vulnerability appears only in the case of psk_ke mode if more than a single pair of entities can possess a single PSK. We provide several practical scenarios where this condition can be easily achieved. Also we propose appropriate mitigation

    Airborne fungi in arctic settlement Tiksi (Russian Arctic, coast of the Laptev Sea)

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    Biodiversity and number of airborne fungi isolated from indoor and outdoor air of different location in the areas of arctic settlement Tiksi (Russian Arctic) are described. Different locations (coastal areas, landscape, streets of Tiksi, abandoned empty houses, flats, public buildings) were observed. Aeromycota characterized by a significant biodiversity (50 species), but only several species were abundant. Airborne fungal spores concentration (CFU) in Tiksi locations was found low. The maximum spore concentrations were observed in air of the abandoned empty houses (inhabited in the past). Many species common for soil were observed at the samples taken at streets and abandoned buildings. Most of them are also known as inhabitants of building materials. Microfungi CFU at settlement territory was twice as high as natural territory. Phospholipase, albuminase and hemolytic activities of microfungi isolates as well as their relation to temperature were studied. Most of the tested isolates demonstrated high levels of all the tested activities. It was concluded that there is a risk of ‘‘mold’’ allergy diseases for the people especially with weakening of immunity at arctic settlement Tiksi. Main sources of the air contamination in arctic settlements and houses could be many anthropogenic substrates which were colonized by soil fungi

    Stabilization system of a bipedal non-anthropomorphic robot AnyWalker

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    International audienceWe present a bipedal walking non-anthropomorphic robot AnyWalker developed in the laboratory of robotics and mechatronics of the Kuban State University. The goal is to be able to overcome obstacles exceeding the size of the robot itself. In addition to the degrees of freedom due to the joints between the links, the robot is equipped with reaction wheels enhancing its dynamic stabilization capabilities. This paper presents a study of the stability zones in the frontal plane of the robot with and without the reaction wheel support
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