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  • 1
    Electronic Resource
    Electronic Resource
    Origin of Regioselectivity in Paterno-Buechi Reactions of Benzoquinones with Alkylidenecycloalkanes (1994)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 116 (1994), S. 1272-1277 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00083a013
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  • 2
    Electronic Resource
    Electronic Resource
    Analyse d'un élément mixte pour le problème de Stokes (1992)
    Springer
    Numerische Mathematik 62 (1992), S. 149-160 
    Details
    ISSN: 0945-3245
    Keywords: 65N30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Description / Table of Contents: Résumé Nous considérons quelques extensions des résultats classiques d'estimation d'erreur pour les problèmes mixtes. Nous étudions en particulier l'effet de l'emploi d'une approximation non conforme et celui de la décomposition de la formeb(·,·) enb 1(·,·) etb 2(·,·). Nous employons cette dćomposition pour affiner certaines estimations dans le cas où la formea(·,·) n'est pas coercive dans la bonne norme. Nous considérons aussi des résultats de dualité dans le cas non conforme.
    Notes: Summary We consider some extensions of the classical error estimates for mixed problems. We take into account, in particular, nonconforming approximations and the splitting of the bilinear formb(·,·), intob 1(·,·) andb 2(·,·). We use this last fact to sharpen some estimates in a case where the forma(·,·) does not have coercivity in the right norm. We also consider duality results in the nonconforming case.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01396224
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  • 3
    Electronic Resource
    Electronic Resource
    Analyse d'un élément mixte pour le problème de Stokes (1992)
    Springer
    Numerische Mathematik 62 (1992), S. 161-188 
    Details
    ISSN: 0945-3245
    Keywords: 65N30
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Description / Table of Contents: Résumé Nous construisons un élément fini mixte pour le problème de Stokes. Cet élément est non conforme. Nous appliquons les résultats de la Partie I pour obtenir des estimations d'erreur optimales. Nous considérons aussi le traitement des conditions de raccords par des multiplicateurs de Lagrange et nous montrons que ces multiplicateurs peuvent être utilisés pour construire une approximation superconvergente.
    Notes: Summary We build a mixed finite element method for the Stokes problem. This method is nonconforming. We apply the results of Part I to prove convergence and obtain optimal error estimates. We also consider the treatment of interface conditions by multipliers and show that a superconvergent approximation can be built from those multipliers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01396225
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  • 4
    Electronic Resource
    Electronic Resource
    Characterization of thermotropism in primary roots of maize: Dependence on temperature and temperature gradient, and interaction with gravitropism (1991)
    Springer
    Planta 184 (1991), S. 410-414 
    Details
    ISSN: 1432-2048
    Keywords: Gravitropism (root) ; Root curvature ; Thermotropism ; Zea (thermotropism)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Thermotropism in primary roots of Zea mays L. was studied with respect to gradient strength (°C · cm−-1), temperature of exposure within a gradient, pre-treatment temperature, and gravitropic stimulation. The magnitude of the response decreased with gradient strength. Maximum thermotropism was independent of gradient strength and pre-treatment temperature. The range of temperature for positive and negative thermotropism did not change with pre-treatment temperature. However, the exact range of temperatures for positive and negative thermotropism varied with gradient strengths. In general, temperatures of exposure lower than 25° C resulted in positive tropic responses while temperatures of exposure of 39° C or more resulted in negative tropic responses. Thermotropism was shown to modify and reverse the normal gravitropic curvature of a horizontal root when thermal gradients were applied opposite the 1 · g vector. It is concluded that root thermotropism is a consequence of thermal sensing and that the curvature of the primary root results from the interaction of the thermal and gravitational sensing systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195344
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  • 5
    Electronic Resource
    Electronic Resource
    Random amplified polymorphic DNA and pedigree relationships in spring barley (1993)
    Springer
    Theoretical and applied genetics 85 (1993), S. 976-984 
    Details
    ISSN: 1432-2242
    Keywords: Kinship coefficient ; Polymerase chain reaction ; Genetic markers ; Hordeum vulgare ; Doubled-haploid lines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We investigated random amplified polymorphic DNA (RAPD) in 27 inbred barley lines with varying amounts of common ancestry and in 20 doubled-haploid (DH) lines from a biparental cross. Of 33 arbitrary 10 base primers that were tested, 19 distinguished a total of 31 polymorphisms. All polymorphisms were scored as dominant genetic markers except for 1, where Southern analysis indicated the presence of two codominant amplification products. The inheritance of 19 RAPD polymorphisms and one morphological trait was studied in the DH lines. There was no evidence for segregation distortion, but a group of four tightly linked loci was detected. The frequencies of RAPD polymorphism in pairs of inbred lines were used to compute values of genetic distance (d), which were compared to kinship coefficients (r) between the same pairs of lines. A linear relationship between r and d was evident, but low values of r gave poor predictions of d. Cluster analysis showed that groups of inbred lines based on r were similar to those based on d with some notable exceptions. RAPD markers can be used to gain information about genetic similarities or differences that are not evident from pedigree information.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215037
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  • 6
    Electronic Resource
    Electronic Resource
    Genetic mapping of turnip mosaic virus resistance in Lactuca sativa (1994)
    Springer
    Theoretical and applied genetics 89 (1994), S. 583-589 
    Details
    ISSN: 1432-2242
    Keywords: Coat protein ; Disease resistance ; Molecular markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Presence of the dominant Tu gene in Lactuca sativa is sufficient to confer resistance to infection by turnip mosaic virus (TuMV). In order to obtain an immunological assay for the presence of TuMV in inoculated plants, the TuMV coat protein (CP) gene was cloned by amplification of a cDNA corresponding to the viral genome using degenerate primers designed from conserved potyvirus CP sequences. The TuMV CP was overexpressed in Escherichia coli, and polyclonal antibodies were produced. To locate Tu on the L. sativa genetic map, F3 families from a cross between cvs “Cobbham Green” (resistant to TuMV) and “Calmar” (susceptible) were genotyped for Tu. Families known to be recombinant in the region containing Tu were infected with TuMV and tested by the indirect enzyme-linked immunosorbent assay (ELISA) using the anti-CP serum. This assay placed Tu between two random amplified polymorphic DNA (RAPD) markers and 3.2 cM from Dm5/8 (which confers resistance to Bremia lactucae). Also, bulked segregant analysis was used to screen for additional RAPD markers tightly linked to the Tu locus. Five new markers linked to Tu were identified in this region, and their location on the genetic map was determined using informative recombinants in the region. Six markers were identified as being linked within 2.5 cM of Tu.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222452
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  • 7
    Electronic Resource
    Electronic Resource
    Complex transition to chaotic flow in a periodic array of cylinders (1991)
    Springer
    Theoretical and computational fluid dynamics 3 (1991), S. 79-93 
    Details
    ISSN: 1432-2250
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract This paper presents a numerical study of the transition to chaos of the flow of a Newtonian fluid in a periodic array of cylinders between two parallel walls. Using tools from dynamical system theory, we identify and characterize the different solutions to the Navier-Stokes equations at different values of the Reynolds number. We show that a very complex transition to chaos occurs for this problem where we first observe two incommensurate frequencies and then a frequency locking followed by a few period doublings following Feigenbaum's route to turbulence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00271618
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  • 8
    Electronic Resource
    Electronic Resource
    An iterative implementation of the Uzawa algorithm for 3-D fluid flow problems (1990)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 10 (1990), S. 429-442 
    Details
    ISSN: 0271-2091
    Keywords: Uzawa algorithm ; Preconditioning ; Incomplete factorization ; Three-dimensional ; Fluid flow ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A new iterative algorithm for the solution of the three-dimensional Navier-Stokes equations by the finite element method is presented. This algorithm is based on a combination of the Uzawa and the Arrow-Hurwicz algorithms and uses a preconditioning technique to enhance convergence. Numerical tests are presented for the cubic cavity problem with two elements, namely the linear brick Q1-P0 and the enriched linear brick Q1+ - P1. It is shown that the proposed methodology is optimal with the enriched element and that the CPU time varies as NEQ1·44, where NEQ is the number of equations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fld.1650100406
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  • 9
    Electronic Resource
    Electronic Resource
    Iterative stabilization of the bilinear velocity-constant pressure element (1990)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 10 (1990), S. 125-140 
    Details
    ISSN: 0271-2091
    Keywords: Incompressible flow ; Finite element ; Stability ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Some finite element approximations of incompressible flows, such as those obtained with the bilinear velocity-constant pressure element (Q1-P0), are well known to be unstable in pressure while providing reasonable results for the velocity.We shall see that there exists a subspace of piecewise constant pressures that leads to a stable approximation. The main drawback associated with this subspace is the necessity of assembling groups of elements, the so-called ‘macro-elements’, which increases dramatically the bandwidth of the system.We study a variant of Uzawa's method which enables us to work in the desired subspace without increasing the bandwidth of the system. Numerical results show that this method is efficient and can be made to work at a low extra cost. The method can easily be generalized to other problems and is very attractive in three-dimensional cases.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fld.1650100202
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  • 10
    Electronic Resource
    Electronic Resource
    Some special purpose preconditioners for conjugate gradient-like methods applied to CFD (1993)
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 16 (1993), S. 581-596 
    Details
    ISSN: 0271-2091
    Keywords: Unsteady ; Incompressible ; Viscous ; Transonic ; Supersonic ; Euler equations ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Standard preconditioners such as incomplete LU decomposition perform well when used with conjugate gradient-like iterative solvers such as GMRES for the solution of elliptic problems. However, efficient computation of convection-dominated problems requires, in general, the use of preconditioners tuned to the particular class of fluid-flow problems at hand. This paper presents three such preconditioners. The first is applied to the finite element computation of inviscid (Euler equations) transonic and supersonic flows with shocks and uses incomplete LU decomposition applied to a matrix with extra artificial dissipation. The second preconditioner is applied to the finite difference computation of unsteady incompressible viscous flow; it uses incomplete LU decomposition applied to a matrix to which a pseudo-compressible term has been added. The third method and application are similar to the second, only the LU decomposition is replaced by Beam-warming approximate factorization. In all cases, the results are in very good agreement with other published results and the new algorithms are found to be competitive with others; it is anticipated that the efficiency and robustness of conjugate-gradient-like methods will render them the method of choice as the difficulty of the problems that they are applied to is increased.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/fld.1650160703
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