1,720,964 research outputs found
Lie and Lagrange Series in Nonlinear Equations with Controlled Evolution
No full textIn this paper we use Groebner's method to solve Cauchy problems for evolution equations, linear or not, which have a controller, i.e. a numerical function or a differential operator. In the former case we improve a well known result for linear problems; in the second case, the solution will be worked out through the integration of a Volterra integral equation having a Lagrange series as operator kernel
A Procedure for Calculating an Approximate Analytical Response of a Large Class of Mechanical Systems
No full textA class of nonlinear implicit Cauchy problems integrated by Groebner's method
No full textThis paper deals with second order Cauchy problems in implicit form, which can be reduced to evolution problems, whose integration is performed, according to the Groebner's method, by means of generalized Lie series
Perturbed Nonlinear Evolution Problems Solved by a Generalized Lie Series Method
No full textIn this paper a classical method by Poincaré is extended to the resolution of a very large class of evolution operators involved in Cauchy problems. This aim is achieved by exploiting and improving an approach formerly due to Groebner
On Picard Iteration and Lie Series in Analytic Evolutionary Problems of Physics
No full textIn this paper a linkage between the well known Picard's iteration method and the generalized Lie series, representative of the solution to an evolutionary Cauchy problem, is presented. It turns out that Picard's procedure can rigorously introduce generalized Lie series since Its steps are the partial sums of those series
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A Biomathematical Study of a Controlled Birth and Death Process Describing Malignancy
Full text linkIn this paper we deal with a mathematical model which describes the malignancy of a cellular clone controlled by drugs or radiant therapy. We first discuss some general ideas which led us to the choice of this model. Furthermore we emphasize the integration method, which uses generalized Lie series to represent the components of the solution, also in sight of possible extensions to similar cases in the theory of stochastic processes
A Nonlinear Model for Controlling the Evolution of Malignant Cells
No full textControlling by drugs of the evolution of a neoplasm is considered. The presented model combines the balance equations of the drug in the host organism and in the tumor with those describing the evolution of the malignant tumor when treated with an active drug
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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