12,866 research outputs found

    Dispersive spherical optical model of neutron scattering from Al27 up to 250 MeV

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    A spherical optical model potential (OMP) containing a dispersive term is used to fit the available experimental database of angular distribution and total cross section data for n + Al27 covering the energy range 0.1- 250 MeV using relativistic kinematics and a relativistic extension of the Schroedinger equation. A dispersive OMP with parameters that show a smooth energy dependence and energy independent geometry are determined from fits to the entire data set. A very good overall agreement between experimental data and predictions is achieved up to 150 MeV. Inclusion of nonlocality effects in the absorptive volume potential allows to achieve an excellent agreement up to 250 MeV.Comment: 13 figures (11 eps and 2 jpg), 3 table

    Анизотропно-пучковая неустойчивость лазерной плазмы

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    При распространении мощного лазерного импульса вдоль внешнего магнитного поля в плазме возбуждается широкий спектр вистлерных мод с частотами ниже электронной циклотронной частоты, что приводит к появлению надтепловых электронов и установлению плато на первоначально максвелловской функции распределения. В результате развивается анизотропно-пучковая неустойчивость и происходит трансформация энергии быстрых электронов в энергию электростатических колебаний плазмы.При розповсюдженні потужного лазерного імпульсу вздовж зовнішнього магнітного поля в плазмі збуджується широкий спектр вістлерних мод з частотами нижче електронної циклотроної частоти, що призводить до появи надтеплових електронів і встановленню плато на первісно максвеллівській функції розподілу. У результаті розвивається анізотропно-пучкова нестійкість і відбувається трансформація енергії швидких електронів в енергію електростатичних коливань плазми.In the propagation of intense laser pulse along the external magnetic field in a plasma excited a wide range of whistler modes with frequencies below the electron cyclotron frequency, which leads to the suprathermal electrons and the establishment of a plateau on the original Maxwellian distribution functions. As a result, develops anisotropically-stream instability and a transformation of fast electron energy in the energy of electrostatic plasma oscillations

    Discerning the relationship between geminiviral infection and vesicle trafficking using virus induced gene silencing

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    Tomato yellow leaf curl disease is one of the most important threats to tomato crops worldwide. One of its causal agents, Tomato yellow leaf curl Sardinian virus (TYLCSV) is a monopartite member of the genus Begomovirus from the family Geminiviridae. Due to the few proteins encoded by their viral genome, geminiviruses rely heavily on host cellular machineries and interact with a wide range of plant proteins to complete all processes required for infection, such as viral replication, movement and suppression or evasion of plant defence mechanisms. The identification of the host proteins involved in viral infection will be an important step towards the understanding of the mechanisms underlying this process. In our laboratory, transgenic Nicotiana benthamiana plants containing a green fluorescent protein (GFP) expression cassette flanked by two direct repeats of the intergenic region of TYLCSV have been constructed (2IR plants). When these plants are infected with TYLCSV, an overexpression of the reporter gene is observed in those cells where the virus is actively replicating. These plants have been used together with virus induced gene silencing (VIGS) in an effort to identify host genes involved in the infection process using a reverse genetics approach. Using this combined technique our group has identified two genes δ-COP and ARF 1, involved in retrograde vesicle trafficking, which are essential for the infectious process. We are currently assaying genes codifying proteins involved in different pathways of the vesicle trafficking system: Sar1b, γ subunit of AP1, Sec24, SYT1 and two that encode the heavy chain of triskelion proteins. Their effect over viral infection will be presented and discussedUniversidad de Málaga. Campues de Excelencia Internacional Andalucía Tech

    Identifying the function of vesicle trafficking in geminiviral infection using virus induced gene silencing

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    Tomato yellow leaf curl Sardinian virus (TYLCSV) is one of the causal agent of the tomato yel-low leaf curl disease, one of the most important threats to tomato crops worldwide. TYLCSV is a monopartite member of the genus Begomovirus from the family Geminiviridae. To carry out a full infection, geminiviruses need to move inside the infected cell and from one cell to an-other for which they depend on diverse cellular factors. While cell-to-cell movement has been described to occur through plasmodesmata, the way in which geminiviruses move inside the host cells is yet unknown. The identification of the host proteins involved in viral infection will be an important step to-wards the understanding of the mechanisms underlying this process. In our laboratory, trans-genic Nicotianabenthamiana plants containing a green fluorescent protein (GFP) expression cassette flanked by two direct repeats of the intergenic region of TYLCSV have been construct-ed (2IR plants). When these plants are infected with TYLCSV, an overexpression of the reporter gene is observed in those cells where the virus replicates. These plants have been used to-gether with virus induced gene silencing (VIGS) in an effort to identify host genes involved in the infection process using a reverse genetics approach. Using this combined technique our group has identified two genes δ-COP and ARF 1, involved in retrograde vesicle trafficking, which are essential for the infectious process. We are current-ly assaying genes codifying proteins involved in different pathways of the vesicle trafficking system: Sar1b, γ subunit of AP1, Sec24, SYT1 and two that encode the heavy chain of triskelion proteins. Their effect over virus infection will be presented and discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    PRINT3D, a Service-Learning Project for Improving Visually Impaired Accessibility Through Educational 3D Printing

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    Well-executed service-learning projects are a high-value educational element. However, these projects commonly focus on overused topics and unbalanced executions which can produce the opposite effect to that desired when working with groups of people with functional diversity. PRINT3D is a service-learning project aimed at improving accessibility for people with visual disabilities while helping primary and secondary school students learn basic engineering skills through 3D design and printing. Under the support of the European Erasmus+ Programme, this project brought together nongovernmental organizations, teacher professional development centers, business enterprises, and educational centers to collaborate for two school years. The project activities aimed to promote empathy with visually impaired individuals, understand their accessibility needs, generate and prototype solutions, work collaboratively, and 3D design and print objects such as subway line plans, facility plans, signage, and artistic objects that are accessible to the visually impaired. The results of the project were increased motivation, social awareness, and technical skills, especially among students with a higher risk of dropping out of school
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