A Nonlinear System Under Combined Periodic and Random Excitation

The anharmonic oscillator under combined sinusoidal and white noise excitation is studied using the Gaussian closure approximation. The mean response and the steady-state variance of the system is obtained by the WKBJ approximation and also by the Fokker Planck equation. The multiple steadystate solutions are obtained and their stability analysis is presented. Numerical results are obtained for a particular set of system parameters. The theoretical results are compared with a digital simulation study to bring out the usefulness of the present approximate theory.

Molecular characterisation, pathogenesis and fungicide sensitivity of Pythium spp. from table beet (Beta vulgaris var. vulgaris) grown in the Lockyer Valley, Queensland

Table beet production in the Lockyer Valley of south-eastern Queensland is known to be adversely affected by soilborne root disease from infection by Pythium spp. However, little is known regarding the species or genotypes that are the causal agents of both pre- and post-emergence damping off. Based on RFLP analysis with HhaI, HinfI and MboI of the PCR amplified ITS region DNA from soil and diseased plant samples, the majority of 130 Pythium isolates could be grouped into three genotypes, designated LVP A, LVP B and LVP C. These groups comprised 43, 41 and 7% of all isolates, respectively. Deoxyribonucleic acid sequence analysis of the ITS region indicated that LVP A was a strain of Pythium aphanidermatum, with greater than 99% similarity to the corresponding P. aphanidermatum sequences from the publicly accessible databases. The DNA sequences from LVP B and LVP C were most closely related to P. ultimum and P. dissotocum, respectively. Lower frequencies of other distinct isolates with unique RFLP patterns were also obtained with high levels of similarity (>97%) to P. heterothallicum, P. periplocum and genotypes of P. ultimum other than LVP B. Inoculation trials of 1- and 4-week-old beet seedlings indicated that compared with isolates of the LVP B genotype, a higher frequency of LVP A isolates caused disease. Isolates with the LVP A, LVP B and LVP C genotypes were highly sensitive to the fungicide Ridomil MZ, which suppressed radial growth on V8 agar between approximately four and thirty fold at 5 μg/mL metalaxyl and 40 μg/mL mancozeb, a concentration far lower than the recommended field application rate.

Mr. and Mrs. Fuerst Berlin, Hans Frankenbach, Wronker Slogau? and Lilienthal Berlin seated at an outdoor table; Brambach, Germany Portraits Goups

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Willy Tese Moses and others seated at an outdoor table; Chile Portraits Groups

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The Gottschalk family seated around the dining table; Seelhorst Strasse 26, Hannover Portraits Family

From left to right: Kurt, Therese nee Molling, Ursula, the maid, Elizabeth and Hal,

Seated portrait of Adele Rosenzweig at table with book Portraits; Women

Stamp on verso reads "Salokipie A608 _ Kassel"

Henriette Gottschalk nee Rothschild with her grandson Franz Catzenstein at the dining table in her garden.

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Studio portrait of Hermann (Lazar Hirsch) Judey, his father Joseph (Mitskun) Judey, and Hermann's cousin Vladimir (Valodya) Barosin seated around a chess table; Riga Portraits Family

Hermann (Lazar Hirsch) Judey, born 1878 Riga and died 1959 New York; Joseph (Mitskun) Judey, born 1854 Vilna and died 1931 Berlin

Periodic Rayleigh waves of finite amplitude on an isotropic solid

Existence of a periodic progressive wave solution to the nonlinear boundary value problem for Rayleigh surface waves of finite amplitude is demonstrated using an extension of the method of strained coordinates. The solution, obtained as a second-order perturbation of the linearized monochromatic Rayleigh wave solution, contains harmonics of all orders of the fundamental frequency. It is shown that the higher harmonic content of the wave increases with amplitude, but the slope of the waveform remains finite so long as the amplitude is less than a critical value.

Lilly Baum seated at a table outdoors reading a newspaper Portraits Women

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Isidor Simon seated at an outdoor table with his wife Friederike nee Falkenburg and two grandchildren, Helmuth and Walther Simon Portraits Family

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Family portrait with six unidentified men and women around a dining table holding up large glasses of beer.

Handwritten caption: Es war einmal (Once upon a time there was)

Portrait of Paula Pohl Rieser nee Wagner seated at an outdoor table Portraits Women

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Expressionist painter Emil Luethy seated at an outdoor dining table Portraits Men

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