501 research outputs found

    Global dynamics and stability limits for planetary systems around HD 12661, HD 38529, HD 37124 and HD 160691

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    In order to distinguish between regular and chaotic planetary orbits we apply a new technique called MEGNO in a wide neighbourhood of orbital parameters determined using standard two-body Keplerian fits for HD 12661, HD 38529, HD 37124 and HD 160691 planetary systems. We show that the currently announced orbital parameters place these systems in very different situations from the point of view of dynamical stability. While HD 38529 and HD 37124 are located within large stability zones in the phase space around their determined orbits, the preliminary orbits in HD 160691 are highly unstable. The orbital parameters of the HD 12661 planets are located in a border region between stable and unstable dynamical regimes, so while its currently determined orbital parameters produce stable regular orbits, a minor change within the margin of error of just one parameter may result in a chaotic dynamical system.Comment: 12 pages, 3 figures, accepted ApJ, revised version following the referee's repor

    Challenges in translating commercial agreements

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    The article studies the incongruity of stylistic organization of an agreement as one of the types of legal discourse in English and Russian. The comparative analysis of certain stylistic differences (lexical, grammatical, and syntactical) and the tips for translation suggested in this concise work are aimed at better understanding and interpreting the legal document of the given format

    Niños con discapacidades en la educación y preparación de la participación de sus padres

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    The article provides an overview of philosophical and humanitarian approaches to training parents in an inclusive education and the training system itself. The study purpose is to substantiate, develop and test a system for preparing parents of children with disabilities for assistance in the education, based on the humanistic approach and the axiological concept of philosophy. These approaches in the parent training system lead society to the fact that parental competencies should be based on the special education methods, techniques and technologies for educating children with special needs; to predict the result of education and manage the correctional and pedagogical process based on an individual approach to the child. The implementation of the developed system resulted in a high level of parents’ readiness to participate in inclusive children education.El artículo proporciona una visión general de los enfoques filosóficos y humanitarios para capacitar a los padres en una educación inclusiva y el sistema de capacitación en sí. El propósito del estudio es corroborar, desarrollar y probar un sistema para preparar a los padres de niños con discapacidades para la asistencia en la educación, basado en el enfoque humanista y el concepto axiológico de la filosofía. Estos enfoques en el sistema de capacitación para padres llevan a la sociedad al hecho de que las competencias de los padres deben basarse en los métodos, técnicas y tecnologías de educación especial para educar a los niños con necesidades especiales; predecir el resultado de la educación y gestionar el proceso correccional y pedagógico basado en un enfoque individual del niño. La implementación del sistema desarrollado resultó en un alto nivel de preparación de los padres para participar en la educación inclusiva de los niños

    A simple and effective method for ultrastructural analysis of mitosis in Drosophila S2 cells

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    © 2016 The AuthorsThe Drosophila S2 tissue culture cells are a widely used system for studies on mitosis. S2 cells are particularly sensitive to gene silencing by RNA interference (RNAi), allowing targeted inactivation of mitotic genes. S2 cells are also well suited for high-resolution light microscopy analysis of mitosis in fixed cells, and can be easily immunostained to detect mitotic components. In addition, S2 cells are amenable to transformation with plasmid encoding fluorescently tagged mitotic proteins, allowing in vivo analysis of their behavior throughout cell division. However, S2 cells have not been widely used for transmission electron microscopy (TEM) analysis, which provides ultrastructural details on the morphology of the mitotic apparatus that cannot be obtained with high-resolution confocal microscopy. Here, we describe a simple method for the ultrastructural analysis of mitosis in Drosophila S2 cells. • Our method, which involves fixation and sectioning of a cell pellet, provides excellent preservation of mitotic structures and allows analysis of a higher number of mitotic divisions per sample, compared to correlative light-electron microscopy.• Dividing cells are randomly oriented within the pellet and are sectioned along different planes, providing all-around information on the structure of the mitotic apparatus

    Development of oncology: origins, present and prospect

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    The aim of the study - defined as an analysis of the evolution of oncology in the history of medicine and ways of developing its treatment in the futureЦель исследования - анализ эволюции онкологии в истории медицины и путей 1000 развития ее лечения в будущем

    Antiproliferative activity of a new derivative from the class of N-glycoside of indolo [2,3-a] pyrrolo [3,4-c] carbazoles

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    The aim of the study was to evaluate an antiproliferative activity of a new, Russian derivative of N-glycoside substituted indolocarbazole 6-amino-12-(α-L-arabinopyranosyl)indolo [2,3-a] pyrrolo [3,4-c] carbazole-5,7-dione (LCS-1208) on models of transplantable tumors of mice and on human tumors in Balb/c nude mic

    Optimized properties of live vaccine influenza reassortant strains obtained by reverse genetics

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    Classical reassortment in developing chicken eggs is a well-established technique for obtaining LAIV strains. Naturally generated reassortant vaccine strains are characterized by high reproductive capacity, genetically stable characteristics of temperature sensitivity and cold resistance, which correspond to the characteristics of the MDV involved in crossing with the epidemic virus. Along with antigenic relevance, natural reassortment ensures attenuation of vaccine strains, good reproduction capacity in upper respiratory tract cells and inability to reproduction in the lower respiratory tract. With classical reassortment, the speed and efficiency of obtaining vaccine reassortants largely depend on the properties of epidemic virus, and therefore cannot be stable. The potential of reverse genetics is attractive because it allows to obtain vaccine reassortants quickly and efficiently, reduce the likelihood of spontaneous mutations; however, the vaccine strain is deprived of the advantages of natural selection, in which the most viable clones are selected. This study presents the results of comparatively assessed A(H3N2) LAIVs obtained in parallel by classical reassortment and reverse genetics according to criteria confirming that vaccine strains inherit the necessary properties that guarantee their harmlessness and high reproduction in chicken embryos. Strains for LAIV obtained by both methods retained all attenuating mutations inherited from the MDV, were highly reproductive at the optimal temperature, with temperature sensitivity corresponded to the MDV. However, strains obtained by reverse genetics, was observed to have partial loss of cold resistance in comparison with that of the MDV and classical reassortants. Reduced cold adaptation may negatively affect vaccine effectiveness. It is important that after several additional passages in chicken embryos at low temperature, the cold resistance of the vaccine strain, assembled by reverse genetics, was increased. Credibly that cold resistance is a phenotypic trait, the degree of manifestation of which depends on the temperature conditions of virus multiplication. The selective factor of reduced incubation temperature is missing in reverse genetics. In order for the cold-adapted phenotype to be fully realized, additional passages at low temperature of RG-reassortants are necessary. Thus, the reverse genetics method using plasmid technology allows to effectively prepare reassortant strains for LAIV. An important stage in obtaining vaccine strains using genetic engineering techniques should be the control of their cold-adapted phenotype and its optimization by additional passages at low temperature

    High Resolution Images of Orbital Motion in the Trapezium Cluster: First Scientific Results from the MMT Deformable Secondary Mirror Adaptive Optics System

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    We present the first scientific images obtained with a deformable secondary mirror adaptive optics system. We utilized the 6.5m MMT AO system to produce high-resolution (FWHM=0.07'') near infrared (1.6 um) images of the young (~1 Myr) Orion Trapezium theta 1 Ori cluster members. A combination of high spatial resolution and high signal to noise allowed the positions of these stars to be measured to within ~0.003'' accuracies. Including previous speckle data (Weigelt et al. 1999), we analyze a six year baseline of high-resolution observations of this cluster. Over this baseline we are sensitive to relative proper motions of only ~0.002''/yr (4.2 km/s at 450 pc). At such sensitivities we detect orbital motion in the very tight theta 1 Ori B2B3 (52 AU separation) and theta 1 Ori A1A2 (94 AU separation) systems. Such motions are consistent with those independently observed by Schertl et al. (2003) with speckle interferometry, giving us confidence that these very small (~0.002''/yr) orbital motions are real. All five members of the theta 1 Ori B system appear likely gravitationally bound. The very lowest mass member of the theta 1 Ori B system (B4) has K' ~11.66 and an estimated mass of ~0.2 Msun. There was very little motion (4+/-15 km/s) detected of B4 w.r.t B1 or B2, hence B4 is possibly part of the theta 1 Ori B group. We suspect that if this very low mass member is physically associated it most likely is in an unstable (non-hierarchical) orbital position and will soon be ejected from the group. The theta 1 Ori B system appears to be a good example of a star formation ``mini-cluster'' which may eject the lowest mass members of the cluster in the near future. This ``ejection'' process could play a major role in the formation of low mass stars and brown dwarfs.Comment: To appear in the December 10, 2003 issue of the Astrophysical Journal 21 pages, 14 figures (some in color, but print OK in B&W

    Superior strength of carbon steel with an ultrafine-grained microstructure and its enhanced thermal stability

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    © 2015, Springer Science+Business Media New York. The paper presents the results of a study on the microstructure and mechanical properties of a medium-carbon steel (0.45 % C) processed by severe plastic deformation (SPD) via high-pressure torsion (HPT). Martensite quenching was first applied to the material, and then HPT processing was conducted at a temperature of 350 °C. As a result, a nanocomposite type microstructure is formed: an ultrafine-grained (UFG) ferrite matrix with fine cementite particles located predominantly at the boundaries of ferrite grains. The processed steel is characterized by a high-strength state, with an ultimate tensile strength over 2500 MPa. Special attention is given to analysis of the thermal stability of the microstructure and properties of the steel after HPT processing in comparison with quenching. It is shown that the thermal stability of the UFG structure produced by HPT is visibly higher than that of quenching-induced martensite. The origin of the enhanced strength and thermal stability of the UFG steel is discussed
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