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  • 1
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleptera ; Scolytidae ; bark beetle ; western pine beetle ; attractant rate ; pheromone ; exo-brevicomin ; frontalin ; myrcene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Racemicezo-brevicomin, racemic frontalin, and myrcene were released at two proportions (5∶1∶400 and 1∶1∶1), each at three levels (1 ×, 10 ×, and 100 ×) in a ponderosa pine forest in central California. The 5∶1∶400 mix was based on an estimate of the relative amounts released from a ponderosa pine under attack by the western pine beetle,Dendroctonus brevicomis. MoreD. brevicomis were trapped at a source of the three compounds released at 5∶1∶400 than were trapped at a source released at 1∶1∶1, at all three levels, but this difference was statistically significant only at the 1 × and 10 × levels. Sex ratio of trapped beetles and distribution of catch at the source of attractant and 5 m away apparently did not differ between relative release rates.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleoptera ; Scolytidae ; bark beetle ; western pine beetle ; pheromone ; interruption ; behavior ; release device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The number of western pine beetles,Dendroctonus brevicomis, trapped at the center of three 90 × 90-m plots was reduced during a 16-hr period after surrounding an attractive source ofexo-brevicomin, frontalin, and myrcene with 16, 48, or 168 sources of the same attractant. Compounds were released from the center of the plot at 1 mg/16 hr/compound, and from the surrounding sources at 4–280 mg/16 hr/compound. About half of these amounts was released between 1530 hr and 1930 hr, the period of peak beetle flight. No treatment differences were apparent in reduction of catch within the range of release rates and spacings tested. When compounds were released continuously from 168 stations for 17 days, catch at the center of a plot was generally lower than catch before or after this period, but fluctuated daily. More beetles were caught on traps hung on ponderosa pines within a plot and the number of these traps catching beetles was greater when compounds were released from all stations than from only the center station. Beetles caught on traps were attracted into the plots from the surrounding forest, but appeared to be dispersed within the plot when compounds were released from many stations.D. brevicomis attacked at least 91 trees in the plots, of which 25 were killed during two summers.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 113-122 
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Coleoptera ; Scolytidae ; bark beetle ; western pine beetle ; pheromone ; attractant ; inhibitor ; exo-brevicomin ; frontalin ; myrcene ; verbenone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract exo-Brevicomin (E), frontalin (F), and myrcene (M) were released at two rates 10-fold apart with verbenone at four rates 10-fold apart, and without verbenone in plots with one trap on a vertical cylinder at the pheromone source and one trap on each of four cylinders 5 m away. Catch of the western pine beetleDendroctonus brevicomis decreased with increasing levels of verbenone at both release rates of EFM, but not all differences in catch were statistically significant. Significantly more beetles were caught at the high rate of EFM than at the low rate, combining all rates of verbenone. The percent of total beetles caught at the center trap tended to decrease with increasing rates of verbenone, but the only statistically significant differences were at the low rate of EFM.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-1561
    Keywords: Dendroctonus brevicomis ; Temnochila chlorodia ; Coleoptera ; Scolytidae ; Trogositidae ; western pine beetle ; attractant ; pheromone ; trap ; behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A sticky trap with 3 m2 surface area was modified by changes in attractant release rate, vertical dispersion of the attractant, and addition of a tree trunk silhouette to the trap axis. As attractant release rate increased, the number ofDendroctonus brevicomis caught at the source of attractant and at 1.5 and 5.2 m above ground on two vertical silhouettes 4.5 m away increased. In one experiment, more beetles were caught at a dispersed source of attractant than at a point source. Fewer beetles were caught at the lower traps on the two outlying silhouettes when a silhouette was at the source, than when no silhouette was at the source. As attractant release rate increased, the catch of a predator,Temnochila chlorodia, increased at the source.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 18 (1982), S. 1699-1717 
    ISSN: 0029-5981
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: Dependence of dynamic response of nonlinear mechanical systems on design variables is analysed. An adjoint variable method is used to derive first- and second-order derivatives of measures of dynamic response with respect to design variables. A computational algorithm is presented for numerical calculation of first and second design derivatives. A simple oscillator example is solved analytically and by the adjoint variable method, with identical results. A burst fire automatic weapon mechanism with linear and nonlinear damping is treated numerically. It is shown that quadratic appriximations of dynamic response, using results of second-order design sensitivity analysis, can be substantially better than conventional linear approximations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-1561
    Keywords: Pinus ponderosa ; Dendroctonus brevicomis ; western pine beetle ; attractant ; interruption ; behavior ; pheromone ; Coleoptera ; Scolytidae ; exo-brevicomin ; frontalin ; myrcene ; verbenone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The catch of the western pine beetle,Dendroctonus brevicomis, at an attractive source of racemicexo-brevicomin, racemic frontalin, and myrcene was reduced by surrounding the source with a grid of 48 stations releasing all three compounds together, orexo-brevicomin alone or myrcene alone. Each compound was released at the rate of 2 mg/24 hr/station. The catch at an attractive bolt cut from a tree being colonized byD. brevicomis was not reduced byexo-brevicomin, but was reduced by the combination ofexo-brevicomin, frontalin, and myrcene in one of two tests. When a transect of traps was placed across a 0.81-hectare plot at six of the 48 stations releasing all three compounds, more beetles were caught at outer than at inner traps. More beetles were caught at unbaited traps on trees in a plot when the three compounds were released than when onlyexo-brevicomin or no compounds were released. A few trees were attacked byD. brevicomis in some of the plots. The antiattractant verbenone released from 48 stations at the rate of 4 mg/24 hr/station did not reduce the catch at an attractive tree bolt.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Communications in Numerical Methods in Engineering 12 (1996), S. 447-454 
    ISSN: 1069-8299
    Keywords: inviscid drops ; coalescence ; boundary element method ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A numerical method is used to simulate the motion of inviscid drops colliding and coalescing at a solid surface. The equations of motion are solved by a boundary element method in which the free surface of the drop is represented by a moving grid. The numerical results include the configuration of the drop during coalescence and the kinetic and potential energies. A numerical example is used to demonstrate the way in which coalescence affects the configuration of the free surface.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 41 (1998), S. 1105-1131 
    ISSN: 0029-5981
    Keywords: infinite elements ; unbounded domains ; acoustics ; finite element methods ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A novel approach to the development of infinite element formulations for exterior problems of time-harmonic acoustics is presented. This approach is based on a functional which provides a general framework for domain-based computation of exterior problems. Special cases include non-reflecting boundary conditions (such as the DtN method). A prominent feature of this formulation is the lack of integration over the unbounded domain, simplifying the task of discretization. The original formulation is generalized to account for derivative discontinuities across infinite element boundaries, typical of standard infinite element approximations. Continuity between finite elements and infinite elements is enforced weakly, precluding compatibility requirements. Various infinite element approximations for two-dimensional configurations with circular interfaces are presented. Implementation requirements are relatively simple. Numerical results demonstrate the good performance of this scheme. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 41 (1998), S. 95-111 
    ISSN: 0029-5981
    Keywords: boundary integral equation ; BEM ; BSM ; Galerkin ; singularity subtraction ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A new spectral Galerkin formulation is presented for the solution of boundary integral equations. The formulation is carried out with an exact singularity subtraction procedure based on analytical integrations, which provides a fast and precise way to evaluate the coefficient matrices. The new Galerkin formulation is based on the exact geometry of the problem boundaries and leads to a non-element method that is completely free of mesh generation. The numerical behaviour of the method is very similar to the collocation method; for Dirichlet problems, however, it leads to a symmetric coefficient matrix and therefore requires half the solution time of the collocation method. © 1998 John Wiley & Sons, Ltd.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 40 (1997), S. 2791-2805 
    ISSN: 0029-5981
    Keywords: finite element methods ; unbounded domains ; acoustics ; Lagrange multipliers ; absorbing boundary conditions ; infinite elements ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: We develop formulations for finite element computation of exterior acoustics problems. A prominent feature of the formulations is the lack of integration over the unbounded domain, simplifying the task of discretization and potentially leading to numerous additional benefits. These formulations provide a suitable basis for hybrid asymptotic-numerical methods in scattering, non-reflecting boundary conditions and infinite elements. © 1997 John Wiley & Sons, Ltd.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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