Search results for "Lauren"

The distinction betweenChondrophycus patentirameusandC. paniculatus(Ceramiales, Rhodophyta)

2000

The red algae Chondrophycus patentirameus (Montagne) Nam (‘patentiramea’) and L. paniculata (C. Agardh) J. Agardh were investigated on the basis of type material and recent collections. Both species show the following features: (i) production of two vegetative pericentral cells from each axial segment; (ii) absence of secondary pit connections between cortical cells; (iii) lack of projecting cortical cells near the apex; (iv) absence of lenticular thickenings in the walls of medullary cells; and (v) perpendicular arrangement of tetrasporangia, each of which is produced from the second pericentral cell in each fertile segment with no additional tetrasporangial pericentral cells. However, C. …

Resolution of singularities for multi-loop integrals

2007

We report on a program for the numerical evaluation of divergent multi-loop integrals. The program is based on iterated sector decomposition. We improve the original algorithm of Binoth and Heinrich such that the program is guaranteed to terminate. The program can be used to compute numerically the Laurent expansion of divergent multi-loop integrals regulated by dimensional regularisation. The symbolic and the numerical steps of the algorithm are combined into one program.

Comparison among three boundary element methods for torsion problems: CPM, CVBEM, LEM

2011

This paper provides solutions for De Saint-Venant torsion problem on a beam with arbitrary and uniform cross-section. In particular three methods framed into complex analysis have been considered: Complex Polynomial Method (CPM), Complex Variable Boundary Element Method (CVBEM) and Line Element-less Method (LEM), recently proposed. CPM involves the expansion of a complex potential in Taylor series, computing the unknown coefficients by means of collocation points on the boundary. CVBEM takes advantage of Cauchy’s integral formula that returns the solution of Laplace equation when mixed boundary conditions on both real and imaginary parts of the complex potential are known. LEM introduces th…

From neurosis to growth in The Fire-Dwellers : "I didn't see that at one time, but I see it now"

1998

Discrete KP Equation and Momentum Mapping of Toda System

2003

Abstract A new approach to discrete KP equation is considered, starting from the Gelfand-Zakhharevich theory for the research of Casimir function for Toda Poisson pencil. The link between the usual approach through the use of discrete Lax operators, is emphasized. We show that these two different formulations of the discrete KP equation are equivalent and they are different representations of the same equations. The relation between the two approaches to the KP equation is obtained by a change of frame in the space of upper truncated Laurent series and translated into the space of shift operators.

Dante “platonico” nella poesia di Lorenzo il Magnifico

2014

La ripresa del corpus dantesco in senso platonico, operata dai dotti del Quattrocento, ha uno dei suoi alfieri in Lorenzo de’ Medici. Il Magnifico, che inizialmente si avvicina alla Commedia con approccio ironico, perviene ben presto – tramite Marsilio Ficino – a una lirica “alta” che assume il Paradiso come testo di riferimento. Mi sembra interessante rilevare come gli spunti danteschi in Lorenzo muovano dalla necessità di porre in rilievo ulteriori modelli filosofici di stampo platonico, ad esempio lo pseudo-Dionigi; il Magnifico rielabora attentamente passi danteschi suggestionati da opere come le Gerarchie celesti, nell’intento, a mio parere, di corroborare la tesi di un “Dante platonic…

De Saint-Venant flexure-torsion problem handled by Line Element-less Method (LEM)

2010

In this paper, the De Saint-Venant flexure-torsion problem is developed via a technique by means of a novel complex potential function analytic in all the domain whose real and imaginary parts are related to the shear stresses. The latter feature makes the complex analysis enforceable for the shear problem. Taking full advantage of the double-ended Laurent series involving harmonic polynomials, a novel element-free weak form procedure, labelled Line Element-less Method (LEM), is introduced, imposing that the square of the net flux across the border is minimized with respect to expansion coefficients. Numerical implementation of the LEM results in systems of linear algebraic equations involv…

Biological and life table parameters of Typhlodromus laurentii and Iphiseius degenerans (Acari, Phytoseiidae) fed on Panonychus citri and pollen of O…

2015

Typhlodromus laurentii and Iphiseius degenerans are two generalist phytoseiid mites, broadly spread in the Mediterranean area, especially in citrus orchards. In the present work we report results on various biological and life table parameters of the two phytoseiids, fed on pollen of Oxalis pes-caprae and various stages of the tetranychid Panonychus citri. Iphiseius degenerans had the shortest post embryonic development (6.53 days), the highest oviposition rate (1.83 eggs/female/day) and the shortest mean time between eggs laid (0.55 day) on Oxalis pollen, whereas the two food types did not influence these parameters in T. laurentii. However, Oxalis pollen showed a positive effect on the su…

Numerical solution of a class of nonlinear boundary value problems for analytic functions

1982

We analyse a numerical method for solving a nonlinear parameter-dependent boundary value problem for an analytic function on an annulus. The analytic function to be determined is expanded into its Laurent series. For the expansion coefficients we obtain an operator equation exhibiting bifurcation from a simple eigenvalue. We introduce a Galerkin approximation and analyse its convergence. A prominent problem falling into the class treated here is the computation of gravity waves of permanent type in a fluid. We present numerical examples for this case.

Blowing up Feynman integrals

2008

In this talk we discuss sector decomposition. This is a method to disentangle overlapping singularities through a sequence of blow-ups. We report on an open-source implementation of this algorithm to compute numerically the Laurent expansion of divergent multi-loop integrals. We also show how this method can be used to prove a theorem which relates the coefficients of the Laurent series of dimensionally regulated multi-loop integrals to periods.