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Добірка наукової літератури з теми "R-function method"

Автор: Grafiati

Опубліковано: 30 травня 2022

Оновлено: 31 травня 2022

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Статті в журналах з теми "R-function method"

Proskurin, A. V., and A. M. Sagalakov. "Modeling duct flow by the R-function method." Journal of Applied and Industrial Mathematics 10, no. 3 (July 2016): 429–34. http://dx.doi.org/10.1134/s1990478916030133.

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Dmitriev, V. I., and J. G. Ingtem. "The Regularized Spline (R-Spline) Method for Function Approximation." Computational Mathematics and Modeling 30, no. 3 (July 2019): 198–206. http://dx.doi.org/10.1007/s10598-019-09447-w.

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Veretel'nik, V. V., V. F. Kravchenko, and V. L. Rvachev. "Design of groove waveguides by the R-function method." Measurement Techniques 36, no. 2 (February 1993): 216–19. http://dx.doi.org/10.1007/bf00977862.

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Hong-wei, Lu, Sun Ying, Lin Min, Li Pi-ding, and Zheng Zheng. "A probability density function method for detecting atrial fibrillation using R–R intervals." Medical Engineering & Physics 31, no. 1 (January 2009): 116–23. http://dx.doi.org/10.1016/j.medengphy.2008.04.013.

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Pál, Ambrus, and Endre Szabó. "The fibration method over real function fields." Mathematische Annalen 378, no. 3-4 (August 15, 2020): 993–1019. http://dx.doi.org/10.1007/s00208-020-02053-x.

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Abstract Let $$\mathbb R(C)$$ R ( C ) be the function field of a smooth, irreducible projective curve over $$\mathbb R$$ R . Let X be a smooth, projective, geometrically irreducible variety equipped with a dominant morphism f onto a smooth projective rational variety with a smooth generic fibre over $$\mathbb R(C)$$ R ( C ) . Assume that the cohomological obstruction introduced by Colliot-Thélène is the only one to the local-global principle for rational points for the smooth fibres of f over $$\mathbb R(C)$$ R ( C ) -valued points. Then we show that the same holds for X, too, by adopting the fibration method similarly to Harpaz–Wittenberg.

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Chrapoński, Jacek, Marian Maliński, Janusz Szala, and Jan Cwajna. "FGM Structure Characterization by Distance Functions and Systematic Scanning Method." Materials Science Forum 567-568 (December 2007): 153–56. http://dx.doi.org/10.4028/www.scientific.net/msf.567-568.153.

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The distance functions such as G(r), K(r), H(r), g(r) and systematic scanning method connected with variance analysis have been used for quantitative characterization of functionally gradient materials structures. The methods have been tested on computer generated 3D model polycrystalline structures with diverse type of gradient function. Usefulness of the presented methods for quantitative description of FGM structures has been evaluated.

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Uvarova, E. A. "R -function method as a supportive extension for the ritz method and least squares method." Journal of Mathematical Sciences 171, no. 4 (November 7, 2010): 466–73. http://dx.doi.org/10.1007/s10958-010-0150-4.

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Rvachev, V. L., and L. V. Kurpa. "Solving stability problems of plates by the R-function method." Strength of Materials 19, no. 6 (June 1987): 843–46. http://dx.doi.org/10.1007/bf01522846.

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Xia, Fengfei, and Shanqing Li. "R-Function and variation method for bending problem of clamped thin plate with complex shape." Advances in Mechanical Engineering 13, no. 7 (July 2021): 168781402110348. http://dx.doi.org/10.1177/16878140211034832.

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Solving ordinary thin plate bending problem in engineering, only a few analytical solutions with simple boundary shapes have been proposed. When using numerical methods (e.g. the variational method) to solve the problem, the trial functions can be found only it exhibits a simple boundary shape. The R-functions can be applied to solve the problem with complex boundary shapes. In the paper, the R-function theory is combined with the variational method to study the thin plate bending problem with the complex boundary shape. The paper employs the R-function theory to express the complex area as the implicit function, so it is easily to build the trial function of the complex shape thin plate, which satisfies with the complex boundary conditions. The variational principle and the R-function theory are introduced, and the variational equation of thin plate bending problem is derived. The feasibility and correctness of this method are verified by five numerical examples of rectangular, I-shaped, T-shaped, U-shaped, and L-shaped thin plates, and the results of this method are compared with that of other literatures and ANSYS finite element method (FEM). The results of the method show a good agreement with the calculation results of literatures and FEM.

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Diógenes, A. N., L. O. E. dos Santos, and C. P. Fernandes. "PARTICLE SIZE DISTRIBUTION CORRECTION METHOD USING A SIMULATED ANNEALING TECHNIQUE." Revista de Engenharia Térmica 10, no. 1-2 (December 31, 2011): 39. http://dx.doi.org/10.5380/reterm.v10i1-2.61950.

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The procedure for obtaining the particle size distribution by visual inspection of a sample involves stereological errors, given the cut of the sample. A cut particle, supposedly spherical, with radius R, will be counted as a circular particle with radius r, r≤R. The difference between r and R depends on how far from the center of the sphere the cut was performed. This introduces errors when the extrapolation of the properties from two to three dimensions during the analysis of a sample. The usual method is to correct the distribution by probabilistic functions, which have large errors. This paper presents a method to reduce the error inherent to this problem. The method is to compute a simulation of the preparation process in a sample whose structure can be described by non-penetrating spheres of various diameters which meet a known probability distribution function, for example, a log-logistic function, or even a constant function. For each distribution radius, a number of spheres is generated and virtually cut, generating a bi-dimensional (2D) distribution. The 2D curves of the spheres distribution obtained in this simulation are compared with that obtained by the experimental procedure and then the parameters of the threedimensional distribution function are adjusted until the 2D curves are similar to the experimental one using the optimization method Simulated Annealing for the curve-fitting. In future this method will be applied to the analysis of the oil reservoir rocks.

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Більше джерел

Дисертації з теми "R-function method"

Kurpa, Lidiya, Olga Mazur, and Igor Tsukanov. "Application of R-Functions Theory to Study Parametric Vibrations and Dynamical Stability of Laminated Plates." Thesis, Точка, 2013. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37087.

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The problem of nonlinear parametric vibrations and stability analysis of the symmetric laminated plates is considered. The proposed method is based on multimode approximation of displacements and solving series auxiliary linear tasks. The main feature of the work is the application of the R-functions theory, which allows investigating parametric vibrations of plates with complex shape and different boundary conditions.

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Awrejcewicz, Jan, Lidiya Kurpa, and Olga Mazur. "Stability investigation of nonlinear vibrations of plates by R-functions method." Thesis, Wydawnictwo Politechniki Łódzkiej, 2007. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37159.

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The parametric vibrations of plates with cutouts subjected to in-plane periodic and compressive loads, are studied. The proposed approach is based on R-functions method and the classical variational approach. The influence of cutouts parameters, as well as static factors of load on stability regions and nonlinear vibrations are investigated.

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Kurpa, Lidiya, and T. Shmatko. "Investigation of Geometrically Nonlinear Vibrations of Laminated Shallow Shells with Layers of Variable Thickness by Meshless Approach." Thesis, Точка, 2013. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37086.

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Geometrically nonlinear vibrations of laminated shallow shells with layers of variable thickness are studied. Nonlinear equations of motion for shells based on the first order shear deformation and classical shells theories are considered. In order to solve this problem we use the numerically-analytical method proposed in work [1]. Accordingly to this approach the initial problem is reduced to consequences of some linear problems including linear vibrations problem, special elasticity ones and nonlinear system of ordinary differential equations in time. The linear problems are solved by the variational Ritz’ method and Bubnov-Galerkin procedure combined with the R-functions theory [2]. To construct the basic functions that satisfy all boundary conditions in case of simply-supported shells we propose new solutions structures. The proposed method is used to solve both test problems and new ones.

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Drake, David M. "Method for Identifying Resting State Networks following Probabilistic Independent Component Analysis." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1416231546.

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Nylén, Erik. "An application portfolio management method - for implementation at SCANIA CV AB." Thesis, KTH, Industriella informations- och styrsystem, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-81364.

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Information Technology (IT) has become a vital tool for most industrial businesses and Scania CV AB is no exception. As the importance of IT generally has increased, the usage and number of applications has grown as well. Applications are substantial assets for an organization that is heavily supported by IT. Consequently, a way of managing applications efficiently and sustaining the costs of applications rather low ? doing more with less ? is required. In addition it is also important, from a business perspective, that applications as part of IT are aligned with business strategies and goals. Application Portfolio Management (APM) is a practice and a business-centric activity aimed to allocate IT resources to support business objectives and strategies; it helps determining the impact of applications and the relative importance of each application in the portfolio to the business. APM attempts to justify and measure the financial benefits of each application relative to the costs of the applications? maintenance and operations. Performing APM successfully is nevertheless a complicated issue, and something that many businesses are challenged with on a daily basis. New applications are constantly and regularly added, downloaded, purchased or selfdeveloped ? too often without any further control. In order to regain the control of the software that automates the business, and ensuring that the applications adds value and reliability to the company, Scania CV AB requires a rigorous and comprehensive method for an APM approach. In this master thesis together with Camilla Palomeques?s thesis1, such a method is provided. These two theses also offer a suggestion on how to proceed with the APM effort at Scania CV AB.

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Mejia, Humberto. "Modeling of a Heat-Induced Buckling of Plates Using the Mesh-free Method." FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1512.

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In the process of engineering design of structural shapes, the flat plate analysis results can be generalized to predict behaviors of complete structural shapes. In this case, the purpose of this project is to analyze a thin flat plate under conductive heat transfer and to simulate the temperature distribution, thermal stresses, total displacements, and buckling deformations. The current approach in these cases has been using the Finite Element Method (FEM), whose basis is the construction of a conforming mesh. In contrast, this project uses the mesh-free Scan Solve Method. This method eliminates the meshing limitation using a non-conforming mesh. I implemented this modeling process developing numerical algorithms and software tools to model thermally induced buckling. In addition, convergence analysis was achieved, and the results were compared with FEM. In conclusion, the results demonstrate that the method gives similar solutions to FEM in quality, but it is computationally less time consuming.

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Awrejcewicz, Jan, Lidiya Kurpa, and Olga Mazur. "Investigation of the parametric vibration of the orthotropic plates subjected to periodic in plane forces by multi-modal approximation and R-functions method." Thesis, NTU "KhPI", 2010. http://repository.kpi.kharkov.ua/handle/KhPI-Press/37138.

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The original method of studying parametric vibrations of orthotropic plate with complex shape is proposed. Suggested approach is based on combined application of variational methods and the R-functions theory. Using the proposed method and developed software the regular and chaotic regimes of T-shaped plate are analyzed.

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Thomas, Armin W. Verfasser], Hauke R. [Akademischer Betreuer] Heekeren, Klaus-Robert [Gutachter] [Akademischer Betreuer] [Müller, Hauke R. [Gutachter] Heekeren, and Russell A. [Gutachter] Poldrack. "Machine learning methods for modeling gaze allocation in simple choice behavior and functional neuroimaging data on the level of the individual / Armin W. Thomas ; Gutachter: Klaus-Robert Müller, Hauke R. Heekeren, Russell A. Poldrack ; Klaus-Robert Müller, Hauke R. Heekeren." Berlin : Technische Universität Berlin, 2020. http://d-nb.info/1223981657/34.

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Thomas, Armin W. [Verfasser], Hauke R. Akademischer Betreuer] Heekeren, Klaus-Robert [Gutachter] [Akademischer Betreuer] [Müller, Hauke R. [Gutachter] Heekeren, and Russell A. [Gutachter] Poldrack. "Machine learning methods for modeling gaze allocation in simple choice behavior and functional neuroimaging data on the level of the individual / Armin W. Thomas ; Gutachter: Klaus-Robert Müller, Hauke R. Heekeren, Russell A. Poldrack ; Klaus-Robert Müller, Hauke R. Heekeren." Berlin : Technische Universität Berlin, 2020. http://nbn-resolving.de/urn:nbn:de:101:1-2020122301024292024902.

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Scipioni, Angel. "Contribution à la théorie des ondelettes : application à la turbulence des plasmas de bord de Tokamak et à la mesure dimensionnelle de cibles." Thesis, Nancy 1, 2010. http://www.theses.fr/2010NAN10125.

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La nécessaire représentation en échelle du monde nous amène à expliquer pourquoi la théorie des ondelettes en constitue le formalisme le mieux adapté. Ses performances sont comparées à d'autres outils : la méthode des étendues normalisées (R/S) et la méthode par décomposition empirique modale (EMD).La grande diversité des bases analysantes de la théorie des ondelettes nous conduit à proposer une approche à caractère morphologique de l'analyse. L'exposé est organisé en trois parties.Le premier chapitre est dédié aux éléments constitutifs de la théorie des ondelettes. Un lien surprenant est établi entre la notion de récurrence et l'analyse en échelle (polynômes de Daubechies) via le triangle de Pascal. Une expression analytique générale des coefficients des filtres de Daubechies à partir des racines des polynômes est ensuite proposée.Le deuxième chapitre constitue le premier domaine d'application. Il concerne les plasmas de bord des réacteurs de fusion de type tokamak. Nous exposons comment, pour la première fois sur des signaux expérimentaux, le coefficient de Hurst a pu être mesuré à partir d'un estimateur des moindres carrés à ondelettes. Nous détaillons ensuite, à partir de processus de type mouvement brownien fractionnaire (fBm), la manière dont nous avons établi un modèle (de synthèse) original reproduisant parfaitement la statistique mixte fBm et fGn qui caractérise un plasma de bord. Enfin, nous explicitons les raisons nous ayant amené à constater l'absence de lien existant entre des valeurs élevées du coefficient d'Hurst et de supposées longues corrélations.Le troisième chapitre est relatif au second domaine d'application. Il a été l'occasion de mettre en évidence comment le bien-fondé d'une approche morphologique couplée à une analyse en échelle nous ont permis d'extraire l'information relative à la taille, dans un écho rétrodiffusé d'une cible immergée et insonifiée par une onde ultrasonore
The necessary scale-based representation of the world leads us to explain why the wavelet theory is the best suited formalism. Its performances are compared to other tools: R/S analysis and empirical modal decomposition method (EMD). The great diversity of analyzing bases of wavelet theory leads us to propose a morphological approach of the analysis. The study is organized into three parts. The first chapter is dedicated to the constituent elements of wavelet theory. Then we will show the surprising link existing between recurrence concept and scale analysis (Daubechies polynomials) by using Pascal's triangle. A general analytical expression of Daubechies' filter coefficients is then proposed from the polynomial roots. The second chapter is the first application domain. It involves edge plasmas of tokamak fusion reactors. We will describe how, for the first time on experimental signals, the Hurst coefficient has been measured by a wavelet-based estimator. We will detail from fbm-like processes (fractional Brownian motion), how we have established an original model perfectly reproducing fBm and fGn joint statistics that characterizes magnetized plasmas. Finally, we will point out the reasons that show the lack of link between high values of the Hurst coefficient and possible long correlations. The third chapter is dedicated to the second application domain which is relative to the backscattered echo analysis of an immersed target insonified by an ultrasonic plane wave. We will explain how a morphological approach associated to a scale analysis can extract the diameter information

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Книги з теми "R-function method"

Hodges, John R. Cognitive Assessment for Clinicians. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780192629760.001.0001.

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This resource aims to incorporate the enormous advances over the last decade in our understanding of cognitive function into clinical practice, particularly the aspects of memory, language and attention. These advances in theory provide a practical approach to cognitive valuation at the bedside, based on methods developed at the Cambridge clinic over the past 15 years. Designed primarily for neurologists, psychiatrists and geriatricians in training who require a practical guide to assessing higher mental function, the resource will also be of interest to clinical psychologists. In this second edition, John Hodges has substantially re-organised and expanded on the original edition. It includes a new chapter devoted to the Revised Version of the Addenbrooke's Cognitive Examination (ACE-R), with a description of its uses and limitations along with normative data. Given the importance of the early detection of dementia, a chapter is dedicated to this topic that draws on advances over the past decade. Several new illustrative case histories have also been added and all of the case descriptions have been orientated around the use of the ACE-R in clinical practice.

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Láruson, Áki Jarl, and Floyd Allan Reed. Population Genetics with R. Oxford University Press, 2021. http://dx.doi.org/10.1093/oso/9780198829539.001.0001.

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Population genetics is an inherently quantitative discipline. Because the focus of population genetics studies is usually on abstract concepts like the frequencies of genetic variants over time, it can at first glance be difficult to conceptualize and appropriately visualize. As more and more quantitative models and methods have become established in the discipline, it has become necessary for people just entering the field to quickly develop a good understanding of the many layers of complex approaches, so as to correctly interpret even basic results. An unfortunate side effect of the widespread implementation of ready-to-use quantitative software packages is that some facets of analysis can become rote, which at best might lead to implementation without the full understanding of the user and at worst, inappropriate application leading to misguided conclusions. In this book a “learning by doing” approach is employed to encourage readers to begin developing an intuitive understanding of population genetics concepts. The analytical software R, which has increasingly been the program of choice for early exposure to basic statistical programming, is freely available online, has cross-platform compatibility (Windows, Mac, and Linux all support distributions of R), and offers the potential for hands-on implementation by the students, in addition to using pre-packaged functions.

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Частини книг з теми "R-function method"

Anarova, Sh A., and Z. E. Ibrohimova. "Methods of Constructing Equations for Objects of Fractal Geometry and R-Function Method." In Intelligent Human Computer Interaction, 425–36. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-98404-5_40.

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Wu, Jianming, Yanling Chen, Peng Guo, Xiaoya Wang, Xiaogong Hu, and Mengjie Wu. "New Method of GNSS-R Wind Speed Retrieval Based on Empirical Orthogonal Function." In Lecture Notes in Electrical Engineering, 262–73. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-3138-2_26.

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Quicke, Donald, Buntika A. Butcher, and Rachel Kruft Welton. "Principal components analysis." In Practical R for biologists: an introduction, 194–99. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789245349.0194.

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Abstract This chapter focuses on how to conduct a principal components analysis. To conduct principal components analysis, R has two similar built-in functions prcomp and princomp in the default stats package. Other implementations can be found in various downloadable packages, e.g. the function PCA from the package FactoMineR, the function dudi.pca from the package ade4 and the function acp from the package amap. The functions prcomp and princomp employ different calculation methods but in practice the results they return will be almost identical.

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Swenson, Nathan G. "Comparative Methods and Phylogenetic Signal." In Functional and Phylogenetic Ecology in R, 147–71. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-9542-0_7.

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Poterasu, V. F., and N. Mihalache. "Brittle Fracture Materials by BEM and R-Functions." In Boundary Element Methods, 298–307. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-662-06153-4_33.

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Hair, Joseph F., G. Tomas M. Hult, Christian M. Ringle, Marko Sarstedt, Nicholas P. Danks, and Soumya Ray. "Overview of R and RStudio." In Classroom Companion: Business, 31–47. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-80519-7_2.

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AbstractComputational statistics is now an increasingly popular method of analysis for researchers that combines a vast array of algorithms, statistical methods, and the power of functional coding. The R programming language, in particular, has benefitted from this development alongside of traditional graphical user interface (GUI) software. Today, it has become the language of choice for empirical researchers. In this chapter, we introduce the R programming language as well as its popular development environment in the form of RStudio. We walk the reader through downloading both the R language and the RStudio integrated development environment (IDE). Then, we discuss the software layout and demonstrate how to interact with the software. Finally, we address creating and managing R projects and scripts, gaining access to documentation and help via various sources. This chapter is not intended as a tutorial on the writing of code in the R programming language. We do, however, provide useful open-source resources for learning R, which can be accessed from the R console RStudio environment.

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Cecot, W., and J. Orkisz. "On Coupling of the Boundary Element and R-Function Methods." In Mathematical and Computational Aspects, 435–45. Berlin, Heidelberg: Springer Berlin Heidelberg, 1987. http://dx.doi.org/10.1007/978-3-662-21908-9_28.

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Moffett, Peter. "Fragment Complementation and Co-immunoprecipitation Assays for Understanding R Protein Structure and Function." In Methods in Molecular Biology, 9–20. Totowa, NJ: Humana Press, 2011. http://dx.doi.org/10.1007/978-1-61737-998-7_2.

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Kleine, Liliana López, Rosa Montaño, and Francisco Torres-Avilés. "Classification and Clustering on Microarray Data for Gene Functional Prediction Using R." In Methods in Molecular Biology, 41–54. New York, NY: Springer New York, 2015. http://dx.doi.org/10.1007/7651_2015_240.

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Тези доповідей конференцій з теми "R-function method"

Veretelnik, V. V. "Calculation of microstrip structures by the r-function method." In International Conference on Millimeter and Submillimeter Waves and Applications 1994. SPIE, 1994. http://dx.doi.org/10.1117/12.2303206.

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Ying-ying, Zhang, and Zhang Xiu-ting. "An R Function for the Multi-classification Fisher Discriminant Method." In 2015 Joint International Social Science, Education, Language, Management and Business Conference. Paris, France: Atlantis Press, 2015. http://dx.doi.org/10.2991/jisem-15.2015.8.

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Kim, Kuk-cheol, and Young-wha Ma. "A Study on the Normalized Load Function for J-R Curve Testing Using Normalization Method." In ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28145.

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The purpose of this study is to suggest a more appropriate normalized load G-function for normalization method of J-R curve testing in the ASTM 1820 standard. For leak before break (LBB) design of reactor coolant piping system, J-R curve testing is required to verify the crack stability integration using J-T analysis. The normalization method of J-R curve testing is an excellent candidate testing method for dynamic J-R curve testing. In the normalization function, the load value is normalized by the G-function based on the plastic η factor. The normalized load function, G-function is important because the resultant J-R curve depends on the normalized function type used. However, for existing J-R curve calculation using the G-function in ASME standards, there exists a mismatch of estimated J integral values between the two different J-integral calculation approaches: the standard method in ASTM 1820, and the approach based on a J-integral physical concept with energy release rate. This problem is caused by the G-function type. To set up a more appropriate G-function, finite element (FE) analysis has been performed for compact tension specimens with various a/W and strain hardening index n. Also, application of the newly proposed G-function to J-R curve estimation is discussed.

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DasNeogi, Protyusha, Elizabeth Cudney, Akim Adekpedjou, and Rodney Kestle. "Comparing the Predictive Ability of T-Method and Cobb-Douglas Production Function for Warranty Data." In ASME 2009 International Mechanical Engineering Congress and Exposition. ASMEDC, 2009. http://dx.doi.org/10.1115/imece2009-12668.

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Predictive models are used in an attempt to anticipate future transitions, mitigate losses, and maximize economic gains. In today’s market, companies look for high reliability and quality of products due to great market competition. Hence warranty data is of considerable interest to companies. Warranty shows the ability of a system or component to perform its functions within a given customer usage. Many statistical and data mining methods are available to predict the warranty data. This study focuses on analyzing the predictive efficiency of the T-method and Cobb-Douglas production function on warranty data by comparing their prediction capability. The T-method, developed by Genichi Taguchi, is founded upon the fundamentals of the Taguchi System of Quality Engineering which is used to calculate an overall prediction based on signal-to-noise ratio. Using this method, the required parameters are calculated to obtain an overall estimate of the true value of the output for each signal member. The Cobb-Douglas production function is then applied on the same dataset. In economics, the Cobb-Douglas functional form of production function is widely used to represent the relationship of the output to inputs. The strength of the relationship is then assessed using the R-squared and adjusted R-squared values.

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Li, Shanqing. "R-function theory method for bending problem of slip clamped trapezoidal shallow spherical shell." In 2017 6th International Conference on Energy and Environmental Protection (ICEEP 2017). Paris, France: Atlantis Press, 2017. http://dx.doi.org/10.2991/iceep-17.2017.4.

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Deng, Suping, Jinghua Yuan, Deshuang Huang, and Zhen Wang. "SFAPS: An R package for structure/function analysis of protein sequences based on informational spectrum method." In 2013 IEEE International Conference on Bioinformatics and Biomedicine (BIBM). IEEE, 2013. http://dx.doi.org/10.1109/bibm.2013.6732455.

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Lopez, P., and Y. Bayazitoglu. "A Note on Modeling of Nano-Scale Thermal Flow via the Lattice Boltzmann Method." In ASME 2012 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/imece2012-89923.

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Lattice Boltzmann (LB) method models have been demonstrated to provide an accurate representation of the flow characteristics in rarefied flows. Conditions in such flows are characterized by the Knudsen number (Kn), defined as the ratio between the gas molecular Mean Free Path ( MFP, λ) and the device characteristic length (L). As the Knudsen number increases, the behavior of the flow near the walls is increasingly dominated by interactions between the gas molecules and the solid surface. Due to this, linear constitutive relations for shear stress and heat flux, which are assumed in the Navier-Stokes-Fourier (NSF) system of equations, are not valid within the Knudsen Layer (KL). Fig. 1 illustrates the characteristics of the velocity field within the Knudsen layer in a shear-driven flow. It is easily observed that although the NSF equations with slip flow boundary conditions (represented by dashed line) can predict the velocity profile in the bulk flow region, they fail to capture the flow characteristics inside the Knudsen layer. Slip flow boundary conditions have also been derived using the integral transform technique [1]. Various methods have been explored to extend the applicability of LB models to higher Knudsen number flows, including using higher order velocity sets, and using wall-distance functions to capture the effect of the walls on the mean free path by incorporating such functions on the determination of the local relaxation parameters. In this study, a high order velocity model which contains a two-dimensional, thirteen velocity direction set (e.g., D2Q13), as shown in Fig. 2, is used as the basis of the current LB model. The LB model consists of two independent distribution functions to simulate the density and temperature fields, while the Diffuse Scattering Boundary Condition (DSBC) method is used to simulate the fluid interaction with the walls. To further improve the characterization of transition flow conditions expected in nano-scale heat transfer, we explored the implementation of two wall-distance functions, derived recently based on an integrated form of a probability distribution function, to the high-order LB model. These functions are used to determine the effective mean free path values throughout the height of the micro/nano-channel, and the resulting effect is first normalized and then used to determine local relaxation times for both momentum and energy using a relationship based on the local Knudsen number. The two wall-distance functions are based on integral forms of 1) the classical probability distribution function, ψ(r) = λ0−1e−r/λ0, derived by Arlemark et al [2], in which λ0represents the reference gas mean free path, and 2) a Power-Law probability distribution function, derived by Dongari et al [3]. Thus, the probability that a molecule travels a distance between r and r+dr between two successive collisions is equal to ψ(r)dr. The general form of the integral of the two functions used can be described by ψ(r) = C − f(r), where f(r) represents the base function (exponential or Power Law), and C is set to 1 so that the probability that a molecule will travel a distance r+dr without a collision ranges from zero to 1. The performance of the present LB model coupled with the implementation of the two wall-distance functions is tested using two classical flow cases. The first case considered is that of isothermal, shear-driven Couette flow between two parallel, horizontal plates separated by a distance H, moving in opposite directions at a speed of U0. Fig. 3 shows the normalized velocity profiles across the micro-channel height for various Knudsen numbers in the transition flow regime based on our LB models as compared to data based on the Linearized Boltzmann equation [4]. The results show that our two LB models provide results that are in excellent agreement with the reference data up to the high end of the transition flow regime, with Knudsen numbers greater than 1. The second case is rarefied Fourier flow within horizontal, parallel plates, with the plates being stationary and set to a constant temperature (TTop > TBottom), and the Prandtl number is set to 0.67 to match the reference data based on the Direct Simulation Monte Carlo (DSMC) method [5]. Fig. 4 shows the normalized temperature profiles across the microchannel height for various Knudsen numbers in the slip/transition How regime. For the entire Knudsen number range studied, our two LB models provide temperature profiles that are in excellent agreement with the non-linear profile seen in the reference data. The results obtained show that the effective MFP relationship based on the exponential function improves the results obtained with the high order LB model for both shear-driven and Fourier flows up to Kn∼1. The results also show that the effective MFP relationship based on the Power Law distribution function greatly enhances the results obtained with the high order LB model for the two cases addressed, up to Kn∼3. In conclusion, the resulting LB models represent an effective tool in modeling non-equilibrium gas flows expected within micro/nano-scale devices.

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Pilgun, Galyna, and Marco Amabili. "Analysis of Nonlinear Forced Vibrations of Shallow Shells With Cut-Outs by Using the R-Function Method." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64349.

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Geometrically nonlinear forced vibrations of shells based on the domains with cut-outs are investigated. Classical nonlinear shallow-shell theories retaining in-plane inertia is used to calculate the strain energy; the shear deformation is neglected. A mesh-free technique based on classic approximate functions and the R-function theory is used to build the discrete model of the nonlinear vibrations. This allowed for constructing the sequences of admissible functions that satisfy given boundary conditions in domains with complex geometries. Shell displacements are expanded by using Chebyshev orthogonal polynomials. A two-step approach is implemented to solve the problem: first a linear analysis is conducted to identify natural frequencies and corresponding natural modes to be used in the second step as a basis for nonlinear displacements. The system of ordinary differential equations is obtained by using Lagrange approach on both steps. The convergence of the solution is studied by using different multimodal expansions. The pseudo-arclength continuation method and bifurcation analysis are used to study the nonlinear equations of motion. Numerical responses are obtained in the spectral neighbourhood of the lowest natural frequency. When possible, obtained results are compared to those available in the literature.

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Li, Shanqing. "R-function theory method for free vibration of slip clamped trapezoidal shallow spherical shell on Winkler foundation." In 2017 2nd International Conference on Civil, Transportation and Environmental Engineering (ICCTE 2017). Paris, France: Atlantis Press, 2017. http://dx.doi.org/10.2991/iccte-17.2017.120.

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Takahashi, Kazuaki, Tetsu Narumi, and Kenji Yasuoka. "Cutoff Radius Effect of Water Configuration Using the Wolf Method." In ASME/JSME 2011 8th Thermal Engineering Joint Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajtec2011-44602.

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Molecular dynamics simulation has been applied for water to compare the Wolf method to the IPS method and the Ewald sum by evaluating the diffusion coefficient and liquid structure. In our previous study, we applied the IPS method for bulk water and found notable deviation of the radial distribution function g(r). The Wolf method gives a good estimation for the potential energy and the self-diffusion coefficient at a cutoff radius, rc, greater than 2.2 nm while avoiding the notable deviation of g(r) which appeared in the case of IPS. The distance dependent Kirkwood factor Gk(r) was also calculated, and the truncation of a long-range interaction of the cutofflike method (such as cutoff with or without the switch function and the reaction field) show serious shortcomings for dipole-dipole correlations in bulk water systems. This was observed by comparing the shape to that of the Ewald sum. Gk(r) of the cutofflike method greatly deviates from that of the Ewald sum. However, the discrepancy of Gk(r) for the Wolf method was found to be much less than that of other typical cutoff-like methods. We conclude that the Wolf method is an adequately accurate technique for estimating transport coefficients and the liquid structure of water in a homogeneous system at long cutoff distances.

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Звіти організацій з теми "R-function method"

Hodges, Thomas K., and David Gidoni. Regulated Expression of Yeast FLP Recombinase in Plant Cells. United States Department of Agriculture, September 2000. http://dx.doi.org/10.32747/2000.7574341.bard.

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Research activities in both our laboratories were directed toward development of control of the FLP/frt recombination system for plants. As described in the text of the research proposal, the US lab has been engaged in developing regulatory strategies such as tissue-specific promoters and the steroid-inducible activation of the FLP enzyme while the main research activities in Israel have been directed toward the development and testing of a copper-regulated expression of flp recombinase in tobacco (this is an example of a promoter activation by metal ions). The Israeli lab hat additionally completed experiments of previous studies regarding factors affecting the efficiency of recombinase activity using both a gain-of-function assay (excisional-activation of a gusA marker) and loss of function assay (excision of a rolC marker) in tobacco. Site-specific recombinase systems, in particular the FLP/frt and R/RS systems of yeast and the Cre/lox system of bacteriophage P1, have become an essential component of targeted genetic transformation procedures both in animal and plant organisms. To provide more flexibility in transgene excisions by the recombinase systems as well as gene targeting, and to widen possible applications, the development of controlled or regulated recombination systems is highly desirable and was therefore the subject of this research proposal. There are a few possible mechanisms to regulate expression of a recombinase system. They include: 1) control of the recombination system by having the target sites (e.g. frt) in one plant and the flp recombinase gene in another, and bringing the two together by cross fertilization. 2) regulation of promoter activities by external stimuli such as temperature, chemicals, metal ions, etc. 3) regulation of promoter activities by internal signals, i.e. cell- or tissue-specific, or developmental regulation. 4) regulation of enzyme activity by providing cofactors essential for biochemical reactions to take place such as steroid molecules in conjunction with a steroid ligand-binding protein (domains). During the course of this research our major emphasis have been focused toward studying the feasibility of hybrid seed production in Arabidopsis, using FLP/frt. Male-sterility was induced using the antisence of a pollen- and tapetum-specific gene, bcp1, isolated from Arabidopsis. The sterility inducing gene was flanked by frt sites. Upon cross pollination of flowers of male-sterile plants with pollen from FLP-containing plants, viable seeds were produced, and the progeny hybrid plants developed normally. The major achievement from this work is the first demonstration of using a site-specific recombinase to restore fertility in male-sterile plants (see attached paper, Luo et al., Plant J 2000; 23:423-430). The implication from this finding is that site-specific recombination systems can be applied in crop plants as a useful alternative method for hybrid seed production.

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Whitham, Steven A., Amit Gal-On, and Victor Gaba. Post-transcriptional Regulation of Host Genes Involved with Symptom Expression in Potyviral Infections. United States Department of Agriculture, June 2012. http://dx.doi.org/10.32747/2012.7593391.bard.

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Understanding how RNA viruses cause disease symptoms in their hosts is expected to provide information that can be exploited to enhance modern agriculture. The helper component-proteinase (HC-Pro) protein of potyviruses has been implicated in symptom development. Previously, we demonstrated that symptom expression is associated with binding of duplex small-interfering-RNA (duplex-siRNA) to a highly conserved FRNK amino acid motif in the HC-Pro of Zucchini yellow mosaic virus (ZYMV). This binding activity also alters host microRNA (miRNA) profiles. In Turnip mosaic virus (TuMV), which infects the model plant Arabidopsis, mutation of the FRNK motif to FINK was lethal providing further indication of the importance of this motif to HC-Pro function. In this continuation project, our goal was to further investigate how ZYMV and TuMV cause the mis-expression of genes in cucurbits and Arabidopsis, respectively, and to correlate altered gene expression with disease symptoms. Objective 1 was to examine the roles of aromatic and positively charged residues F164RNH and K215RLF adjacent to FR180NK in small RNA binding. Objective 2 was to determine the target genes of the miRNAs which change during HC-Pro expression in infected tissues and transgenic cucumber. Objective 3 was to characterize RNA silencing mechanisms underlying differential expression of host genes. Objective 4 was to analyze the function of miRNA target genes and differentially expressed genes in potyvirus-infected tissues. We found that the charged K/R amino acid residues in the FKNH and KRLF motifs are essential for virus viability. Replacement of K to I in FKNH disrupted duplex-siRNA binding and virus infectivity, while in KRLF mutants duplex-siRNA binding was maintained and virus infectivity was limited: symptomless following a recovery phenomenon. These findings expanded the duplex-siRNA binding activity of HC-Pro to include the adjacent FRNK and FRNH sites. ZYMV causes many squash miRNAs to hyper-accumulate such as miR166, miR390, mir168, and many others. Screening of mir target genes showed that only INCURVATA-4 and PHAVOLUTA were significantly upregulated following ZYMVFRNK infection. Supporting this finding, we found similar developmental symptoms in transgenic Arabidopsis overexpressing P1-HC-Pro of a range of potyviruses to those observed in miR166 mutants. We characterized increased transcription of AGO1 in response to infection with both ZYMV strains. Differences in viral siRNA profiles and accumulation between mild and severe virus infections were characterized by Illumina sequencing, probably due to the differences in HC-Pro binding activity. We determined that the TuMV FINK mutant could accumulate and cause symptoms in dcl2 dcl4 or dcl2 dcl3 dcl4 mutants similar to TuMV FRNK in wild type Arabidopsis plants. These dcl mutant plants are defective in antiviral defenses, and the results show that factors other than HC-ProFRNK motif can induce symptoms in virus-infected plants. As a result of this work, we have a better understanding of the FRNK and FKNH amino acid motifs of HC-Pro and their contributions to the duplex-siRNA binding functions. We have identified plant genes that potentially contribute to infectivity and symptoms of virus infected plants when they are mis-expressed during potyviral infections. The results establish that there are multiple underlying molecular mechanisms that lead viral pathogenicity, some dependent on HC-Pro. The potential benefits include the development of novel strategies for controlling diseases caused by viruses, methods to ensure stable expression of transgenes in genetically improved crops, and improved potyvirus vectors for expression of proteins or peptides in plants.

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Lichter, Amnon, Gopi K. Podila, and Maria R. Davis. Identification of Genetic Determinants that Facilitate Development of B. cinerea at Low Temperature and its Postharvest Pathogenicity. United States Department of Agriculture, March 2011. http://dx.doi.org/10.32747/2011.7592641.bard.

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Botrytis cinerea is the postharvest pathogen of many agricultural produce with table grapes, strawberries and tomatoes as major targets. The high efficiency with which B. cinerea causes disease on these produce during storage is attributed in part due to its exceptional ability to develop at very low temperature. Our major goal was to understand the genetic determinants which enable it to develop at low temperature. The specific research objectives were: 1. Identify expression pattern of genes in a coldenriched cDNA library. 2. Identify B. cinerea orthologs of cold-induced genes 3. Profile protein expression and secretion at low temperature on strawberry and grape supplemented media. 4. Test novel methods for the functional analysis of coldresponsive genes. Objective 1 was modified during the research because a microarray platform became available and it allowed us to probe the whole set of candidate genes according to the sequence of 2 strains of the fungus, BO5.10 and T4. The results of this experiment allowed us to validate some of our earlier observations which referred to genes which were the product of a SSH suppression-subtraction library. Before the microarray became available during 2008 we also analyzed the expression of 15 orthologs of cold-induced genes and some of these results were also validated by the microarray experiment. One of our goals was also to perform functional analysis of cold-induced genes. This goal was hampered for 3 years because current methodology for transformation with ‘protoplasts’ failed to deliver knockouts of bacteriordopsin-like (bR) gene which was our primary target for functional analysis. Consequently, we developed 2 alternative transformation platforms, one which involves an air-gun based technique and another which involves DNA injection into sclerotia. Both techniques show great promise and have been validated using different constructs. This contribution is likely to serve the scientific community in the near future. Using these technologies we generated gene knockout constructs of 2 genes and have tested there effect on survival of the fungus at low temperature. With reference to the bR genes our results show that it has a significant effect on mycelial growth of the B. cinerea and the mutants have retarded development at extreme conditions of ionic stress, osmotic stress and low temperature. Another gene of unknown function, HP1 is still under analysis. An ortholog of the yeast cold-induced gene, CCH1 which encodes a calcium tunnel and was shown to be cold-induced in B. cinerea was recently cloned and used to complement yeast mutants and rescue them from cold-sensitivity. One of the significant findings of the microarray study involves a T2 ribonuclease which was validated to be cold-induced by qPCR analysis. This and other genes will serve for future studies. In the frame of the study we also screened a population of 631 natural B. cinerea isolates for development at low temperature and have identified several strains with much higher and lower capacity to develop at low temperature. These strains are likely to be used in the future as candidates for further functional analysis. The major conclusions from the above research point to specific targets of cold-induced genes which are likely to play a role in cold tolerance. One of the most significant observations from the microarray study is that low temperature does not induce ‘general stress response in B. cinerea, which is in agreement to its exceptional capacity to develop at low temperature. Due to the tragic murder of the Co-PI Maria R. Davis and GopiPodila on Feb. 2010 it is impossible to deliver their contribution to the research. The information of the PI is that they failed to deliver objective 4 and none of the information which relates to objective 3 has been delivered to the PI before the murder or in a visit to U. Alabama during June, 2010. Therefore, this report is based solely on the IS data.

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Phillips, Donald, and Yoram Kapulnik. Using Flavonoids to Control in vitro Development of Vesicular Arbuscular Mycorrhizal Fungi. United States Department of Agriculture, January 1995. http://dx.doi.org/10.32747/1995.7613012.bard.

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Vesicular-arbuscular mycorrhizal (VAM) fungi and other beneficial rhizosphere microorganisms, such as Rhizobium bacteria, must locate and infect a host plant before either symbiont profits. Although benefits of the VAM association for increased phosphorous uptake have been widely documented, attempts to improve the fungus and to produce agronomically useful amounts of inoculum have failed due to a lack of in vitro production methods. This project was designed to extend our prior observation that the alfalfa flavonoid quercetin promoted spore germination and hyphal growth of VAM fungi in the absence of a host plant. On the Israeli side of the project, a detailed examination of changes in flavonoids and flavonoid-biosynthetic enzymes during the early stages of VAM development in alfalfa found that VAM fungi elicited and then suppressed transcription of a plant gene coding for chalcone isomerase, which normally is associated with pathogenic infections. US workers collaborated in the identification of flavonoid compounds that appeared during VAM development. On the US side, an in vitro system for testing the effects of plant compounds on fungal spore germination and hyphal growth was developed for use, and intensive analyses of natural products released from alfalfa seedlings grown in the presence and absence of microorganisms were conducted. Two betaines, trigonelline and stachydrine, were identified as being released from alfalfa seeds in much higher concentrations than flavonoids, and these compounds functioned as transcriptional signals to another alfalfa microsymbiont, Rhizobium meliloti. However, these betaines had no effect on VAM spore germination or hyphal growth i vitro. Experiments showed that symbiotic bacteria elicited exudation of the isoflavonoids medicarpin and coumestrol from legume roots, but neither compound promoted growth or germination of VAM fungi in vitro. Attempts to look directly in alfalfa rhizosphere soil for microbiologically active plant products measured a gradient of nod-gene-inducing activity in R. meliloti, but no novel compounds were identified for testing in the VAM fungal system in vitro. Israeli field experiments on agricultural applications of VAM were very successful and developed methods for using VAM to overcome stunting in peanuts and garlic grown in Israel. In addition, deleterious effects of soil solarization on growth of onion, carrot and wheat were linked to effects on VAM fungi. A collaborative combination of basic and applied approaches toward enhancing the agronomic benefits of VAM asociations produced new knowledge on symbiotic biology and successful methods for using VAM inocula under field conditions

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Sessa, Guido, та Gregory Martin. MAP kinase cascades activated by SlMAPKKKε and their involvement in tomato resistance to bacterial pathogens. United States Department of Agriculture, січень 2012. http://dx.doi.org/10.32747/2012.7699834.bard.

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The research problem: Pseudomonas syringae pv. tomato (Pst) and Xanthomonas campestrispv. vesicatoria (Xcv) are the causal agents of tomato bacterial speck and spot diseases, respectively. These pathogens colonize the aerial parts of the plant and cause economically important losses to tomato yield worldwide. Control of speck and spot diseases by cultural practices or chemicals is not effective and genetic sources of resistance are very limited. In previous research supported by BARD, by gene expression profiling we identified signaling components involved in resistance to Xcvstrains. Follow up experiments revealed that a tomato gene encoding a MAP kinase kinase kinase (MAPKKKe) is required for resistance to Xcvand Pststrains. Goals: Central goal of this research was to investigate the molecular mechanisms by which MAPKKKεand associated MAP kinase cascades regulate host resistance. Specific objectives were to: 1. Determine whether MAPKKKεplays a broad role in defense signaling in plants; 2. Identify components of MAP kinase cascades acting downstream of MAPKKKε; 3. Determine the role of phosphorylation-related events in the function of MAPKKKε; 4. Isolate proteins directly activated by MAPKKKε-associatedMAPK modules. Our main achievements during this research program are in the following major areas: 1. Characterization of MAPKKKεas a positive regulator of cell death and dissection of downstream MAP kinase cascades (Melech-Bonfil et al., 2010; Melech-Bonfil and Sessa, 2011). The MAPKKKεgene was found to be required for tomato resistance to Xcvand Pstbacterial strains and for hypersensitive response cell death triggered by different R gene/effector gene pairs. In addition, overexpression analysis demonstrated that MAPKKKεis a positive regulator of cell death, whose activity depends on an intact kinase catalytic domain. Epistatic experiments delineated a signaling cascade downstream of MAPKKKεand identified SIPKK as a negative regulator of MAPKKKε-mediated cell death. Finally, genes encoding MAP kinase components downstream of MAPKKKεwere shown to contribute to tomato resistance to Xcv. 2. Identification of tomato proteins that interact with MAPKKKεand play a role in plant immunity (Oh et al., 2011). We identified proteins that interact with MAPKKKε. Among them, the 14-3-3 protein TFT7 was required for cell death mediated by several R proteins. In addition, TFT7 interacted with the MAPKK SlMKK2 and formed homodimersin vivo. Thus, TFT7 is proposed to recruit SlMKK2 and MAPKKK client proteins for efficient signal transfer. 3. Development of a chemical genetic approach to identify substrates of MAPKKKε-activated MAP kinase cascades (Salomon et al., 2009, 2011). This approach is based on engineering the kinase of interest to accept unnatural ATP analogs. For its implementation to identify substrates of MAPKKKε-activated MAP kinase modules, we sensitized the tomato MAP kinase SlMPK3 to ATP analogs and verified its ability to use them as phosphodonors. By using the sensitized SlMPK3 and radiolabeled N6(benzyl)ATP it should be possible to tag direct substrates of this kinase. 4. Development of methods to study immunity triggered by pathogen-associated molecular patterns (PAMPs) in tomato and N. benthamiana plants (Kim et al., 2009; Nguyen et al. 2010). We developed protocols for measuring various PTI-associatedphenotypes, including bacterial populations after pretreatment of leaves with PAMPs, induction of reporter genes, callose deposition at the cell wall, activation of MAP kinases, and a luciferase-based reporter system for use in protoplasts. Scientific and agricultural significance: Our research activities discovered and characterized a signal transduction pathway mediating plant immunity to bacterial pathogens. Increased understanding of molecular mechanisms of immunity will allow them to be manipulated by both molecular breeding and genetic engineering to produce plants with enhanced natural defense against disease. In addition, we successfully developed new biochemical and molecular methods that can be implemented in the study of plant immunity and other aspects of plant biology.

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