1,721,012 research outputs found
The calculation of bioavailable testosterone
No full textM. Haren, B.E.C. Nordin, C.E.M. Pearce, P. O’Loughlin, I. Chapman, J.E. Morley and G.A. Witterthttp://www.medimond.com/proceedings/moreinfo/20010615.ht
Geometric probability based stereological corrections
Get PDFIn mineral processing, a classic problem is that of estimating the particle composition distribution from particle sections. This problem occurs because mineralogical analysis is performed on particle sections rather than the particles. Thus one wishes to infer three-dimensional information (particle composition distribution) from two-dimensional information (particle sections). There are a number of different techniques available for estimating the particle composition distribution and these are called stereological corrections. This paper provides examples of very simple stereological corrections based on geometric probability equations as well as the principle of maximum entropy. The paper focuses on three methods. The first method is a simple entropy based model based on particle section information only. The second method also uses entropy, but the entropy is based on relating particles to particle sections, and is therefore more complex than the first. The third model uses both the particle section distribution and the linear intercept distribution. The most accurate model is that which uses both particle sections and linear intercepts
Midpoint Type Rules from an Inequalities Point of View
No full textThe article investigates interior point rules which contain the midpoint as a special case, and obtains explicit bounds through the use of a Peano kernel approach and the modern theory of inequalities. Thus the simplest open Newton-Cotes rules are examined. Both Riemann-Stieltjes and Riemann integrals are evaluated with a variety of assumptions about the integrand enabling the characterisation of the bound in terms of a variety of norms. Perturbed quadrature rules are obtained through the use of Grüss, Chebychev and Lupaş inequalities, producing a variety of tighter bounds. The implementation is demonstrated through the investigation of a variety of composite rules based on inequalities developed. The analysis allows the determination of the partition required that would assure that the accuracy the result would be within a prescribed error tolerance. It is demonstrated that the bounds of the approximations are equivalent to those obtained from a Peano kernel that produces Trapezoidal type rules
Long time scale molecular dynamics using least action
Get PDFWe present here an efficient method for evaluating molecular trajectories over long time scales. The method is based on optimisation of the path action defined by classical mechanics. We test the technique on non-trivial examples drawn from the literature and discuss the effectiveness of this approach in the study of molecular processes. Many of the present techniques for calculating molecular trajectories are limited computationally. Standard forward integration of Newton's equations of motion yields accurate results for a range of systems whose transition times are many orders of magnitude less than most biologically interesting processes. If one wants to extend these calculations to biologically relevant time scales, it is necessary to develop methodologies which avoid this limitation. The process outlined in this paper has been tested on simple systems using harmonic and Lennard--Jones potential energy functions. The algorithm yields stable trajectories and is adjustable to suite available computational resources. In theory, this algorithm is applicable to any molecular system where the initial and final states are known. This could include investigation of chemical reactions, ligand/receptor binding and work cycles of molecular machinery
AN INTEGRAL APPROXIMATION IN THREE VARIABLES
No full textCommunicated by C.E.M. Pearce ABSTRACT. In this paper we will investigate a method of approximating an integral in three independent variables. The Ostrowski type inequality is established by the use of Peano kernels and provides a generalisation of a result given by Pachpatte. Key words and phrases: Ostrowski inequality, Three independent variables, Partial derivatives
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Variations on the Author
Get PDF“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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