121 research outputs found

    Effect of stellar wind induced magnetic fields on planetary obstacles of non-magnetized hot Jupiters

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    We investigate the interaction between the magnetized stellar wind plasma and the partially ionized hydrodynamic hydrogen outflow from the escaping upper atmosphere of non- or weakly magnetized hot Jupiters. We use the well-studied hot Jupiter HD 209458b as an example for similar exoplanets, assuming a negligible intrinsic magnetic moment. For this planet, the stellar wind plasma interaction forms an obstacle in the planet's upper atmosphere, in which the position of the magnetopause is determined by the condition of pressure balance between the stellar wind and the expanded atmosphere, heated by the stellar extreme ultraviolet (EUV) radiation. We show that the neutral atmospheric atoms penetrate into the region dominated by the stellar wind, where they are ionized by photo-ionization and charge exchange, and then mixed with the stellar wind flow. Using a 3D magnetohydrodynamic (MHD) model, we show that an induced magnetic field forms in front of the planetary obstacle, which appears to be much stronger compared to those produced by the solar wind interaction with Venus and Mars. Depending on the stellar wind parameters, because of the induced magnetic field, the planetary obstacle can move up to ~0.5-1 planetary radii closer to the planet. Finally, we discuss how estimations of the intrinsic magnetic moment of hot Jupiters can be inferred by coupling hydrodynamic upper planetary atmosphere and MHD stellar wind interaction models together with UV observations. In particular, we find that HD 209458b should likely have an intrinsic magnetic moment of 10-20% that of Jupiter.Comment: 8 pages, 6 figures, 2 tables, accepted to MNRA

    Pathomorphological and pathochemical characteristic of the osteomyelitis focus in patients with diabetic osteoarthropathy (Charcot foot)

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    BACKGROUND: Osteomyelitis in diabetic osteoarthropathy occurs in 65 % of cases, and it is the main cause of non-traumatic amputations. The choice of optimal treatment technologies should be based on understanding the pathogenetic characteristics of this disease.AIM: To study the pathomorphological and pathochemical picture of osteomyelitic focus in patients with diabetic neuroosteoarthropathy.MATERIALS AND METHODS: Object β€” 20 patients (55.3Β±9.33 years) with Type 2 diabetes mellitus, diabetic neuroosteoarthropathy, chronic osteomyelitis of the foot bones. The treatment consisted in surgical debridement of the purulent focus with the material collection for pathomorphological and biochemical studies, and in reposition and alignment of bone fragments with the leg and foot fixation using the Ilizarov fixator in order to form bone ankylosis of the compromised joint.RESULTS: Subacute and acute course of chronic osteomyelitis was registered in 80 % of cases. As for the pathohistological changes in bone tissue, the following ones were the most significant: necrosis and the presence of an inflammatory infiltrate of varying severity depending on the phase of the inflammatory process. The articular cartilage structure was broken in all the cases. Activation of osteoclasts was observed in the osteomyelitis focus, especially in the subchondral zone. There was no subchondral bone plate in most cases, or only its fragments remained. Pathohistological examination of the soft tissues associated with the osteomyelitis focus indicated the presence of mirocirculatory and denervation disorders due to necrosis and hyalinosis of a significant part of microvessels against the background of compensatory hypervascularisation and chronic inflammation, narrowing and obliteration of the lumens of feeding arteries, almost complete absence of nerve elements in the tissues or their destructive changes. An increase in the activity of lytic enzymes was revealed in the interstitial environment of the tissues surrounding the osteomyelitis focus (138-fold increase in the activity of acid phosphatase, interstitial osteolytic index was 7.2-fold higher than blood serum index).CONCLUSION: The pathomorphological signs of chronic osteomyelitis subacute and acute processing were observed in most patients. Breaking the articular cartilage structure was accompanied by invasion of vessels, inflammatory infiltrate, and by activation of osteoclasts in the subchondral zone. Destructive changes of vessels and nerves in the soft tissues associated with the osteomyelitis focus can be etiopathogenetic factors of this disease development. The technologies for stopping this process should be based on obligatory debridement of the focus with sequestrnecrectomy, with regular monitoring of theΒ operated segment condition

    Self-trapping and stable localized modes in nonlinear photonic crystals

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    We predict the existence of stable nonlinear localized modes near the band edge of a two-dimensional reduced-symmetry photonic crystal with a Kerr nonlinearity. Employing the technique based on the Green function, we reveal a physical mechanism of the mode stabilization associated with the effective nonlinear dispersion and long-range interaction in the photonic crystals.Comment: 4 pages (RevTex) with 5 figures (EPS

    A survey on software defect prediction using deep learning

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    Defect prediction is one of the key challenges in software development and programming language research for improving software quality and reliability. The problem in this area is to properly identify the defective source code with high accuracy. Developing a fault prediction model is a challenging problem, and many approaches have been proposed throughout history. The recent breakthrough in machine learning technologies, especially the development of deep learning techniques, has led to many problems being solved by these methods. Our survey focuses on the deep learning techniques for defect prediction. We analyse the recent works on the topic, study the methods for automatic learning of the semantic and structural features from the code, discuss the open problems and present the recent trends in the field. Β© 2021 by the authors. Licensee MDPI, Basel, Switzerland

    Anthrax in the Territory of Dagestan

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    The aim of the study is to investigate anthrax epizootiologic and epidemiologic situation in the Republic of Dagestan over the period of 1944–2010. Anthrax morbidity has been registered in 38 regions and Makhachkala. All in all 1001 anthrax cases and 3128 sick rural animals have been registered. Determined are 420 anthrax specified potentially hazardous areas (SPHA), the majority of them (77.4 %) have formed before 1969. Regions of the republic have been checked against the level of risk connected with anthrax infecting over the last 40 years. Therewith, they have been classified into three groups: with low, medium, and high epizootiological-and-epidemiological potential. 15 regions with high epizootiological-and-epidemiological potential have been marked as potentially hazardous on a regular basis. These regions occupy 31 % of the republic`s territory and 52.5 % of the SPHA territory. 84 % of patients and 88 % of fallen animals have been registered there for the past 40 years

    Studies of Genetic Diversity of Yersinia pestis Strains Isolated in Central-Caucasian High-Mountain Natural Plague Focus

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    Studied have been Yersinia pestis strains isolated in Central-Caucasian high-mountain natural plague focus within the period of 1971–2012 using MLVA typing on 25 VNTR-loci. Analysis of dendrogram cluster association with certain areas, objects, and periods of the strain isolation has been carried out by means of Arc GIS 10.1 software. Established has been the connection between 25 MLVA Y. pestis types and spatial and temporal characteristics of strains isolation in the Central-Caucasian high-mountain natural plague focus, and proline requirement too. Clusters, groups and subgroups of the strains are confined to particular territories as it follows: groups are attributed to landscape-epizootiological regions, subgroups – to mountain souslik settlements. Occasionally groups of the strains disseminate onto the other landscape-epizootiological regions of the focus. Genetic variations of plague agent strains within the limits of mountain souslik settlements evolve over time which can be viewed as indirect evidence of microevolution mechanism effect

    Attempt to produce element 120 in the 244 Pu + 58 Fe reaction

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    An experiment aimed at the synthesis of isotopes of element 120 has been performed using the 244 Pu( 58 Fe,xn) 302βˆ’x 120 reaction. No decay chains consistent with fusion-evaporation reaction products were observed during an irradiation with a beam dose of 7.1 Γ— 10 18 330-MeV 58 Fe projectiles. The sensitivity of the experiment corresponds to a cross section of 0.4 pb for the detection of one decay
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