Large temperature dependence of the Casimir force at the metal-insulator transition

The dependence of the Casimir force on material properties is important for both future applications and to gain further insight on its fundamental aspects. Here we derive a general theory of the Casimir force for low-conducting compounds, or poor metals. For distances in the micrometer range, a large variety of such materials is described by universal equations containing a few parameters: the effective plasma frequency, dissipation rate of the free carriers, and electric permittivity in the infrared range. This theory can also describe inhomogeneous composite materials containing small regions with different conductivity. The Casimir force for mechanical systems involving samples made with compounds that have a metal-insulator transition shows an abrupt large temperature dependence of the Casimir force within the transition region, where metallic and dielectric phases coexist.Comment: 23 pages, 9 figure

Electron Beam Instability in Left-Handed Media

We predict that two electron beams can develop an instability when passing through a slab of left-handed media (LHM). This instability, which is inherent only for LHM, originates from the backward Cherenkov radiation and results in a self-modulation of the beams and radiation of electromagnetic waves. These waves leave the sample via the rear surface of the slab (the beam injection plane) and form two shifted bright circles centered at the beams. A simulated spectrum of radiation has well-separated lines on top of a broad continuous spectrum, which indicates dynamical chaos in the system. The radiation intensity and its spectrum can be controlled either by the beams' current or by the distance between the two beams.Comment: 4 pages, 4 figure

Quantum electromechanics: Quantum tunneling near resonance and qubits from buckling nanobars

Analyzing recent experimental results, we find similar behaviors and a deep analogy between three-junction superconducting qubits and suspended carbon nanotubes. When these different systems are ac-driven near their resonances, the resonance single-peak, observed at weak driving, splits into two sub-peaks (Fig. 1) when the driving increases. This unusual behavior can be explained by considering quantum tunneling in a double well potential for both systems. Inspired by these experiments, we propose a mechanical qubit based on buckling nanobars--a NEMS so small as to be quantum coherent. To establish buckling nanobars as legitimate candidates for qubits, we calculate the effective buckling potential that produces the two-level system and identify the tunnel coupling between the two local states. We propose different designs of nanomechanical qubits and describe how they can be manipulated. Also, we outline possible decoherence channels and detection schemes. A comparison between nanobars and well studied superconducting qubits suggests several future experiments on quantum electromechanics.Comment: 6 pages, 3 figures, 1 tabl

Epidemiological Situation on Tick-Borne Borreliosis in the Russian Federation in 2021 and Forecast for 2022

3875 cases of tick-borne borreliosis (TBB) (2.65 per 100000 of population) were recorded in Russia in 2021. Compared to 2020, 61 out of 78 constituent entities experienced a decrease in the incidence rate in 2021. Over the past year, the largest number of cases was registered in the Central Federal District (CFD) – 1797 cases, which is 46.4 % of cases in Russia. Second in the rank by the number of cases of TBB comes the Siberian FD (SFD) – 616 cases (15.9 %), followed by Ural FD – 445 cases (11.5 %), the North-Western FD – 418 (10.8 %), and the Volga FD – 388 (10 %). 134 (3.5 %) and 60 (1.5 % of the total number of cases of TBB) cases were registered in the Far Eastern and Southern Federal Districts, respectively. The last place is occupied by the North Caucasus Federal District (NCFD), where 17 cases were registered, the share of which in the total structure of cases in Russia is 0.4 %. When assessing the long-term dynamics of TBB incidence, a significant trend towards a decrease in the intensity of the epidemic process has been revealed for the North-Western FD, UFD and VFD, as opposed to the CFD and Southern FD, where a significant upward trend was noted. For the Russian Federation on the whole, the Siberian FD, FEFD and NCFD the variation in the incidence rates within the confidence intervals of the long-term annual average values is most likely to be observed in the near future

The London theory of the crossing-vortex lattice in highly anisotropic layered superconductors

A novel description of Josephson vortices (JVs) crossed by the pancake vortices (PVs) is proposed on the basis of the anisotropic London theory. The field distribution of a JV and its energy have been calculated for both dense ($a\lambda_J$) PV lattices with distance $a$ between PVs, and the nonlinear JV core size $\lambda_J$. It is shown that the ``shifted'' PV lattice (PVs displaced mainly along JVs in the crossing vortex lattice structure), formed in high out-of-plane magnetic fields transforms into the PV lattice ``trapped'' by the JV sublattice at a certain field, lower than $\Phi_0/\gamma^2s^2$, where $\Phi_0$ is the flux quantum, $\gamma$ is the anisotropy parameter and $s$ is the distance between CuO$_2$ planes. With further decreasing $B_z$, the free energy of the crossing vortex lattice structure (PV and JV sublattices coexist separately) can exceed the free energy of the tilted lattice (common PV-JV vortex structure) in the case of $\gamma s<\lambda_{ab}$ with the in-plane penetration depth $\lambda_{ab}$ if the low ($B_x<\gamma\Phi_0/\lambda_{ab}^2$) or high ($B_x\gtrsim \Phi_0/\gamma s^2$) in-plane magnetic field is applied. It means that the crossing vortex structure is realized in the intermediate field orientations, while the tilted vortex lattice can exist if the magnetic field is aligned near the $c$-axis and the $ab$-plane as well. In the intermediate in-plane fields $\gamma\Phi_0/\lambda_{ab}^2\lesssim B_x \lesssim \Phi_0/\gamma s^2$, the crossing vortex structure with the ``trapped'' PV sublattice seems to settle in until the lock-in transition occurs since this structure has the lower energy with respect to the tilted vortex structure in the magnetic field ${\vec H}$ oriented near the $ab$-plane.Comment: 15 pages, 6 figures, accepted for publication in PR

Epidemiological Situation on Tick-Borne Borreliosis in the Russian Federation in 2019 Compared to the Period of 2002–2018

Objective: to analyze the epidemiological situation on Ixodidae tick-borne borreliosis in the Russian Federation in 2019 in comparison with the period of 2002–2018.Materials and methods. The paper uses the data contained in Form No. 2 of the state statistical reporting for 2002–2019 and information obtained by the Reference Center for Monitoring Borreliosis of the Omsk Research Institute of Natural Focal Infections from 74 constituent entities of Russia in 2019. The main research method is epidemiological one with the use of modern information technologies.Results and discussion. In Russia, 8048 cases of tick-borne borreliosis (Lyme disease – LD) were recorded (5.48 0/0000) in 2019. The actual indicators of the LD incidence for the whole country and federal districts (FD) in 2019 were within the confidence limits predicted with linear regression based on the study of the dynamics of the epidemic process in 2002–2018 in the vast majority of cases. A steady upward trend in the LD incidence was observed during 2002–2019 in the Central Federal District due to 10 out of 18 entities (Moscow, Belgorod, Lipetsk, Moscow, Bryansk, Voronezh, Kursk, Ryazan, Tambov, Tula regions); in the Southern Federal District because of the Krasnodar Territory and the Volgograd Region; in the North Caucasus Federal District – because of the Stavropol Territory. Despite the fact that a downward trend in the incidence of LD has been established over the past 18 years in the North-West, Volga and Ural Federal Districts, in some subjects of these regions a trend towards an aggravation of the epidemiological situation is observed (the Komi Republic and Chuvashia, Penza Region). In the absence of a pronounced tendency to change in the incidence rate of LD in the Siberian and Far Eastern Federal Districts, Kemerovo Region-Kuzbass, the Republic of Tuva and the Trans-Baikal Territory where a growing trend has been identified require special attention. In the Ural and Siberian Federal Districts, the share of non-erythema forms among laboratory-confirmed cases of LD was higher than in other regions, which merits further study of the genome-specific features of borrelia populations and their carriers. Effective control of the LD epidemiological situation in Russia is possible provided that the control is improved and maintained, and the capacity of preventive measures and zoological-entomological monitoring of the activity and structure of the natural foci of LD is enhanced in the entities with the long-term tendency towards increase in the incidence of the disease

Review of the Epidemiological Situation on Ixodic Tick-Borne Borrelioses in the Russian Federation in 2013–2022 and Forecast for 2023

The aim of the review was to characterize the epidemiological situation on ixodic tick-borne borreliosis (ITBB) in the constituent entities of the Russian Federation in 2022, to forecast the development of the ITBB epidemic process in 2023 based on the analysis of its trends in the period of 2013–2022. In total, 7 264 cases of ITBB were registered in the Russian Federation in 2022, which is 1.9 times higher than the 2021-value. In all regions in 2022, after a sharp decrease in the level of registered morbidity during the “covid” phase of 2020–2021, there was an incidence raise to the pre-pandemic level. During 2013–2022, distinctive features of the trends in the development of the ITBB epidemic process in the territories of varying degree of epidemic hazard were retained. A downward tendency in the incidence rates was revealed in 14 out of 18 entities with a long-term average annual incidence (LTAA) of ITBB above 6.2 0 /0000, with the exception of Moscow and the Kaluga Region, where a further increase in the incidence of ITBB is possible. In 6 out of 16 regions with LTAA 2013–2022 between 3.31 and 6.2 0 /0000, an upward trend was observed, and in 8 – a decrease in morbidity. The trend towards an increase in morbidity was detected in 7 out of 21 entities with LTAA of ITBB from 1.21 to 3.3 0 /0000 and in 15 out of 26 regions with a low LTAA 2013–2022 (below 1.2 0 /0000). The analysis of trends in the development of the ITBB epidemic process against the trends in changes in the frequency of contacts of the population with ticks, as well as calculations of the probable incidence rate allowed us to conclude that the incidence rate of ITBB in 2023 will range within the confidence intervals of long-term average annual values for the majority of the federal districts, with the exception of the Central Federal District, where an increase in the number of cases of ixodic tick-borne borreliosis is likely to occur, provided that the existing volumes of preventive measures are maintained and abnormal climatic phenomena absent. Effective control of the epidemic situation on the ITBB is attainable through preservation, and for such areas as Moscow, the Moscow Region, Voronezh, Kaluga, Orel, Ryazan, Penza and Rostov Regions, the Republic of Buryatia – increase in the volume of preventive measures, strengthening zoological and entomological monitoring of activity and structure of natural foci. There is an obvious need to develop algorithms for molecular-genetic monitoring of pathogens circulating in natural foci, and to focus attention onto the problems of diagnosis and prophylaxis of tick-borne transmissible infections

Эффективность газомоторного топлива для сельхозтехники

Expediency and efficiency of use of natural gas motor fuel (GMF) for mobile agricultural machinery is defined on the basis of alternative calculations of commercial effectiveness of use of the compressed natural gas (CNG), liquefied natural gas (LNG) and the liquefied petroleum gas (LPG) in large agricultural enterprise «Kazminskoye» in the Stavropol Territory where costs of fuel for machines and tractors make 222.5 million rubles a year. Need of field gas refueling of tractors and combines as a specifics fuel utilization by mobile agricultural machinery was considered at calculations. For an assessment of a type of GMF and influence of cost of a refueling complex on commercial effectiveness the authors have carried out comparative calculations of technical and economic efficiency of utilization of CNG, LNG and LPG, taking into account and without a refueling complex. High efficiency of GMF utilization was showed: fuel costs decrease by 1.7 times, the payback period of capital investments equals to 0.4-4.2 years. The best results were obtained when utilization LPG. Total costs of re-equipment and a refueling complex in option with LPG are 3.5 times as less as with CNG, and 6 times as less as with LNG. The payback period of capital investments for re-equipment without refueling complex equals to 0.4; 0.8 and 2.4 years respectively for LPG, CNG and LNG. Taking into account refueling means it increases to 0.9; 2.4 and 4.2 years. In 10 years the net present value taking into account refueling means equals to 276.7 million; 289.9 million and 206.8 million rubles for LPG, CNG and LNG respectively due to fleet re-equipment.В настоящее время в связи с растущим диспаритетом цен на топливо и сельхозпродукцию весьма актуальной задачей для сельхозтехники является поиск более дешевого альтернативного моторного топлива. Наиболее реальной альтернативой нефтяным моторным топливам выступает газомоторное топливо (ГМТ). Целесообразность и эффективность использования газомоторного топлива для мобильной сельхозтехники определили на основе вариантных расчетов коммерческой эффективности применения компримированного природного газа (КПГ), сжиженного природного газа (СПГ) и сжиженного углеводородного газа (СУГ) в крупном сельхозпредприятии «Казьминское», площадью пашни более 30 тыс. га, его автотракторный парк включает 365 ед., в том числе 279 тракторов, из них 32 мощных трактора «Кировец», затраты на топливо по автотракторной технике составляют 222,5 млн руб. в год. При расчетах учитывали специфику применения моторного топлива для мобильной сельхозтехники, для которой необходима полевая заправка тракторов и комбайнов. Для оценки вида ГМТ и влияния стоимости заправочного комплекса на коммерческую эффективность выполнили сравнительные расчеты технико-экономической эффективности применения КПГ, СПГ и СУГ с учетом и без учета заправочного комплекса. Исходные данные расчетов определяли по результатам приемочных испытаний сельхозтехники на машинно-испытательных станциях. Расчеты по технико-экономическому обоснованию целесообразности использования ГМТ потвердели высокую экономическую эффективность их применения. Показали высокую эффективность применения ГМТ: затраты на топливо снижаются в 1,7 раза, срок окупаемости капитальных вложений: 0,4-4,2 года. Лучшие результаты получены при использовании СУГ, суммарные затраты на переоборудование и заправочный комплекс в варианте с СУГ в 3,5 раза меньше, чем с КПГ, и в 6 раз меньше чем с СПГ. Срок окупаемости капиталовложений на переоборудование техники без заправочного комплекса составляет 0,4; 0,8 и 2,4 года соответственно для СУГ, КПГ и СПГ, с учетом заправочных средств он возрастает до 0,9; 2,4 и 4,2 лет. Чистый дисконтированный доход за 10 лет от переоборудования парка с учетом заправочных средств составляет для СУГ, КПГ и СПГ соответственно 276,7 млн; 289,9 млн; 206,8 млн рублей

Flux-pinning mediated superconducting diode effect in NbSe2/CrGeTe3 heterostructure

In ferromagnet/superconductor bilayer systems, dipolar fields from the ferromagnet can create asymmetric energy barriers for the formation and dynamics of vortices through flux pinning. Conversely, the flux emanating from vortices can pin the domain walls of the ferromagnet, thereby creating asymmetric critical currents. Here, we report the observation of a superconducting diode effect (SDE) in a NbSe2/CrGeTe3 van der Waals heterostructure in which the magnetic domains of CrGeTe3 control the Abrikosov vortex dynamics in NbSe2. In addition to extrinsic vortex pinning mechanisms at the edges of NbSe2, flux-pinning-induced bulk pinning of vortices can alter the critical current. This asymmetry can thus be explained by considering the combined effect of this bulk pinning mechanism along with the vortex tilting induced by the Lorentz force from the transport current in the NbSe2/CrGeTe3 heterostructure. We also provide evidence of critical current modulation by flux pinning depending on the history of the field setting procedure. Our results suggest a method of controlling the efficiency of the SDE in magnetically coupled van der Waals superconductors, where dipolar fields generated by the magnetic layer can be used to modulate the dynamics of the superconducting vortices in the superconductors

Test-System for Identification of Typical and Genetically Altered Variants of Cholera Vibrios, Biovar El Tor, Using Real-Time PCR

The aim of the work was to analyze and assess the results of using PCR test-system “V. cholerae variant ctxB-rtxC FL genes” for identification of Vibrio cholerae O1 with differentiation between typical toxigenic and genetically modified variants in a multiplex format with a real-time hybridization-fluorescent recording of results. Materials and methods. To achieve this goal, a set of reagents for the PCR test-system “V. cholerae O1 variant ctxB-rtxC FL genes”, as well as a method for identifying V. cholerae O1 with differentiation between typical toxigenic and genetically altered variants were utilized. The specificity, specific activity and sensitivity of the developed test-system by the example of 35 V. cholerae O1 strains, 6 V. cholerae non-O1 strains, 5 heterologous strains (Shigella zonnei – 2 strains, one Salmonella typhimurium strain, S. enteritidis, Escherichia coli) were investigated. Results and discussion. The panel of reagents for the PCR test system “V. cholerae variant ctxB-rtxC FL genes” detects DNA fragments of the ctxBCl, ctxBEl, rtxC genes in the genome of toxigenic V. cholerae О1 (has specific activity, analytical sensitivity 1·103 GE/ml) and does not detect these genes in non-toxigenic V. cholerae O1 and non-O1, as well as in heterologous strains of microorganisms (100 % specificity). RF Patent No. 2732448 was granted for the PCR test-system “V. cholerae variant ctxB-rtxC FL genes”. It can be used to increase the efficiency of the epidemiological surveillance system and to carry out a justified scope of anti-epidemic measures in the event of cholera importation into the territory of the Russian Federation