5,214 research outputs found
Nearly conservative multivalue methods for separable Hamiltonian problems
No full textThis talk investigates the canonical properties of general linear methods for long time integration of Hamiltonian problems. It is known that
the classical symplecticity property is important for the accurate numerical solution of Hamiltonian problems and this is only possible for "canonical"
Runge-Kutta methods. Even if general linear methods cannot be symplectic (see [3]), it is possible to lead them inherit a nearly canonical behavior
from their nonlinear stability properties. This is done by imposing a further algebraic constraint on their coecient matrices, known as G-symplecticity
[1], which is a rst requirement to obtain an accurate conservation of the invariants of an Hamiltonian problem. Special attention will be given to the
numerical treatment of separable Hamiltonian problems: to this purpose, the family of G-symplectic partitioned general linear methods is introduced [2]. Due to their multivalue nature, partitioned general linear methods generate parasitic components of the numerical solution which needs to be properly removed: we discuss how G-symplectic partitioned general linear methods free from parasitism can be constructed. We also consider the eects of G-symplecticity on the order of convergence of the derived methods, by exploiting the theory of B-series. Numerical experiments on a selection of separable Hamiltonian problems are discussed. This is a joint work with J. C. Butcher from the University of Auckland
(New Zealand). [1] J. C. Butcher 2008 Numerical methods for Ordinary Dierential Equations, Second Edition, Wiley. [2] J. C. Butcher, R. D'Ambrosio, Partitioned general linear methods for separable Hamiltonian problems, in preparation. [3] J. C. Butcher and L. L. Hewitt 2009 The existence of symplectic general linear methods, Numer. Algor. 51, 77-84
Book Review: Perspectives on volunteering: Voices from the South by Butcher, J., & Einolf, C. J. (Eds.)
No full textBook review of Butcher J. and Einolf C. J. (Eds.). (2017). Perspectives on volunteering: Voices from the South. Cham, Switzerland: Springer. 297 pp.
Published in Nonprofit and Voluntary Sector Quarterly, Volume 47, Issue 6, Pages: 1313 - 1316
Cyranorogas depardieui Quicke and Butcher 2015, sp. nov.
No full textC. depardieui Quicke and Butcher sp. nov. (Figures 1–3) Holotype ♀, Papua-New-Guinea, Province Madang, Mt Wilhelm 1700 m (−5.759269,145.2356), 28–29/10/2012, leg Valeba, Tulei, Novotny, Leponce, Plot 4, understorey; Malaise – MAL-MW1700D-04/16-d04. Length of body 3 mm. Antenna with 25 flagellomeres. Median flagellomeres approximately 1.9× longer than wide. Length of fore wing 3 mm. Precoxal sulcus, deep, rather short, crenulate, located rather low down side of mesopleuron. Scutellar sulcus wide, deep, curved, with six strong carinae between outer ones. Mesopleuron largely smooth and shiny. Propodeum with midlongitudinal carina on anterior 0.7, where it divides to form a weak transverse carina, and posteror to this propodeum irregularly rugose. Body largely honey-yellow, posterior of propodeum, base of hind coxa narrowly, metasomal tergites 1 and 2 and basal part of tergum 3 white. Wings hyaline with brown venation. Etymology. Named in honour of the actor Gérard Depardieu who played Cyrano de Bergerac in the 1990 film adaptation.Published as part of Butcher, Buntika A. & Quicke, Donald L. J., 2015, A remarkable new genus and species of Rogadinae (Hymenoptera: Braconidae) of uncertain tribal placement, from Papua New Guinea, resembling Betylobraconini stat. nov., pp. 2045-2054 in Journal of Natural History 49 (33) on page 2047, DOI: 10.1080/00222933.2015.1009405, http://zenodo.org/record/399800
Analysis of Runge-Kutta methods using Butcher tableaus
No full textThis Bachelor thesis provides an analysis of Runge-Kutta methods using Butcher tableaus. Runge-Kutta method are numerical methods used for approximating initial value problems. A Runge-Kutta method can be classified as either an explicit or an implicit method. A special kind of implicit methods are diagonally implicit methods. The type of method can be recognised by the Butcher tableau. Using the entries of the Butcher tableau, one can compute the amplification factor of a Runge-Kutta method. The amplification factor can then be used to compute the order of the local truncation error and the stability region. Examples of these computations are given for seven methods. Furthermore, this thesis provides an algorithm to perform time steps for each of the three types of Runge-Kutta methods. Finally, in order to analyse the global truncation error of the seven methods, the algorithm to perform time steps is used with different step sizes.Applied Mathematic
FIGURE 1 in Preembobracon gen. nov. (Hymenoptera: Braconidae: Doryctinae: Ypsistocerini: Embobraconina) from Brazil
No full textFIGURE 1. Preembobracon zaldivarriveroni gen. et sp. nov. (A) Habitus; (B) face, front view; (C) head and mesosoma, lateral view; (D) mesosoma, top view.Published as part of Quicke, Donald L. J. & Butcher, Buntika A., 2015, Preembobracon gen. nov. (Hymenoptera: Braconidae: Doryctinae: Ypsistocerini: Embobraconina) from Brazil, pp. 275-280 in Zootaxa 4000 (2) on page 277, DOI: 10.11646/zootaxa.4000.2.5, http://zenodo.org/record/23723
FIGURE 5. K in Three new species of Kerevata (Braconidae: Rogadinae: Clinocentrini) from mainland Papua New Guinea
No full textFIGURE 5. K. hammondi sp. nov. A, habitus; B, mesosoma, dorsal view; C, head, front view; D, head, dorsal view.Published as part of Butcher, Buntika Areekul & Quicke, Donald L. J., 2014, Three new species of Kerevata (Braconidae: Rogadinae: Clinocentrini) from mainland Papua New Guinea, pp. 338-346 in Zootaxa 3811 (3) on page 344, DOI: 10.11646/zootaxa.3811.3.4, http://zenodo.org/record/22751
Aleiodes hircus Butcher, Smith, Sharkey & Quicke, 2012, sp. nov.
No full text<i>Aleiodes hircus</i> sp. nov. <p>(Fig. 85)</p> <p>Holotype ♀, 28.x.2007, Thailand, Mae Hong Son, Namtok Mae Surin NP, nature trail, 19° 20.616' N, 97° 69.3' E, 334m, Areerat & Kamkhun (voucher BCLDQ01616, Genbank JN278348) (QSBG).</p> <p>Paratype 1 sex unknown, Vietnam, Cat Tien NP, 9.x.2005, C. van Achterberg (voucher BCLDQ00349, Genbank JF962851) (RMNH).</p> <p>Body length 5.4 mm, fore wing length 4.6 mm and antenna length 7.0 mm.</p> <p> Antenna with 46 flagellomeres. Terminal flagellomere acuminate. Median flagellomeres approximately 2.2 x longer than wide. Occipital carina produced anteriorly near the middle, obliterated medially, ventrally joining hypostomal carina. Mesopleuron largely aciculate, anteriorly and dorsally rugose, precoxal sulcus weakly impressed, rugulose, specular area with reduced conchoidal-aciculate sculpture. Midlongitudinal carina of propodeum complete though weak and irregular posteriorly. Fore wing vein 2-CU1 1.45 x 1-CU1. Apex of fore wing subbasal cell with glabrous zone. Fore wing vein 3-SR 1.45 x vein r. Fore wing vein 2-SR+M 0.85 x vein r. Fore wing vein SR1 2.6 x vein 3-SR. Hind wing vein M+CU 1.8 x 1-M. Hind wing subbasal cell evenly setose. Hind wing with vein m-cu present as a long straight pigmented line, interstitial. Apex of hind tibia with comb of specialised adpressed setae. Claws with pecten of 7 or 8 closely spaced, but clearly separate, slender teeth on basal lobe. Basal lobes of 1 st tergite moderately produced, steeply concave posteriorly. Midlongitudinal carina of 3 rd tergite well developed on anterior 0.8 of tergum.</p> <p> Etymology. Latin for a she-goat in allusion to the goattee beard shaped mark on the 4 th tergite.</p> <p>Notes. Vietnamese specimen has identical DNA sequence to holotype. An additional sequenced ♀, Thailand, Chonburi Province, Chon Buri, Khao Kaew, grassy area outside zoo conference centre, 15.viii.2009, Quicke, Butcher & Butcher (voucher BCLDQ01281, Genbank HM435203) was destroyed by ants.</p>Published as part of <i>Butcher, Buntika Areekul, Smith, M. Alex, Sharkey, Mike J. & Quicke, Donald L. J., 2012, A turbo-taxonomic study of Thai Aleiodes (Aleiodes) and Aleiodes (Arcaleiodes) (Hymenoptera: Braconidae: Rogadinae) based largely on COI barcoded specimens, with rapid descriptions of 179 new species, pp. 1-232 in Zootaxa 3457</i> on pages 113-114, DOI: 10.11646/ZOOTAXA.3457.1.1, <a href="http://zenodo.org/record/10832362">http://zenodo.org/record/10832362</a>
Marguerite Spoerri Butcher, Roman Provincial Coinage, vol. VII : De Gordien Ier à Gordien III (238 - 244 ap. J.-C), 1. Province d'Asie
No full textCollas E. Marguerite Spoerri Butcher, Roman Provincial Coinage, vol. VII : De Gordien Ier à Gordien III (238 - 244 ap. J.-C), 1. Province d'Asie. In: Revue numismatique, 6e série - Tome 164, année 2008 pp. 494-497
Elevation of intracellular cAMP inhibits RhoA activation and integrin-dependent leukocyte adhesion induced by chemoattractants.
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