Williams, Helen
2010-01-01
As part of an NCETM project, the author is involved with three local schools investigating how engaging in role play might aid children's mathematical development. The project embraces children ranging from part-time Reception to Y4. In this extract, two Reception-age girls, Rachel and Connie, are playing in their classroom spacecraft, and need a…
African Journals Online (AJOL)
Githiomi, Rachel. Vol 18, No 2 (2016) - Articles Prevalence of weak RhD phenotype in the blood donor population of Nairobi Regional Blood Transfusion Centre - Kenya Abstract. ISSN: 1560-8646. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL ...
Indian Academy of Sciences (India)
the basis for various fields of mathematics and the general relativity theory of Einstein. In 1857 ... This idea explained the work on algebraic ... theory, Riemann found the key to the problem of the distribution of primes, in that he associated it ...
Tips From Former Smokers â Brett
Centers for Disease Control (CDC) Podcasts
2014-07-07
Brett had gum diseaseâa danger for all smokers. Brett talks about having most of teeth pulled during one long surgery. Created: 7/7/2014 by Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion. Date Released: 7/7/2014.
International Nuclear Information System (INIS)
Rogers, Alice
1990-01-01
A super Riemann surface is a particular kind of (1,1)-dimensional complex analytic supermanifold. From the point of view of super-manifold theory, super Riemann surfaces are interesting because they furnish the simplest examples of what have become known as non-split supermanifolds, that is, supermanifolds where the odd and even parts are genuinely intertwined, as opposed to split supermanifolds which are essentially the exterior bundles of a vector bundle over a conventional manifold. However undoubtedly the main motivation for the study of super Riemann surfaces has been their relevance to the Polyakov quantisation of the spinning string. Some of the papers on super Riemann surfaces are reviewed. Although recent work has shown all super Riemann surfaces are algebraic, some areas of difficulty remain. (author)
Treating Cataracts: Dr. Rachel Bishop's Top Tips for Your Eyes
... please turn JavaScript on. Feature: Treating Cataracts Dr. Rachel Bishop's Top Tips for Your Eyes Past Issues / ... exams, a healthy lifestyle, and eye protection. Dr. Rachel Bishop, chief of consult services at the National ...
The Silent Spring of Rachel Carson.
Kerstetter, Ned
1996-01-01
Presents a lesson plan examining Rachel Carson's call to arms concerning the harmful consequences of pesticides. Students view a video documentary on Carson's work and read a synopsis of her book, "Silent Spring." Assessment is provided by various activities including writing assignments, creating posters, and editorial cartoons. (MJP)
Riemann, topology, and physics
Monastyrsky, Michael I
2008-01-01
This significantly expanded second edition of Riemann, Topology, and Physics combines a fascinating account of the life and work of Bernhard Riemann with a lucid discussion of current interaction between topology and physics. The author, a distinguished mathematical physicist, takes into account his own research at the Riemann archives of Göttingen University and developments over the last decade that connect Riemann with numerous significant ideas and methods reflected throughout contemporary mathematics and physics. Special attention is paid in part one to results on the Riemann–Hilbert problem and, in part two, to discoveries in field theory and condensed matter such as the quantum Hall effect, quasicrystals, membranes with nontrivial topology, "fake" differential structures on 4-dimensional Euclidean space, new invariants of knots and more. In his relatively short lifetime, this great mathematician made outstanding contributions to nearly all branches of mathematics; today Riemann’s name appears prom...
2691-IJBCS-Article-Rachel A Koum
African Journals Online (AJOL)
hp
http://indexmedicus.afro.who.int. Evaluation de la compétitivité des systèmes piscicoles pratiqués en Côte d'Ivoire: gestion, alimentation et production. Hortense A. YAO1,2, Rachel A. KOUMI2*, Céline Sidonie K. NOBAH3,. Célestin B. ATSE2 et Paul E. KOUAMELAN1. 1UFR Biosciences, Université Félix Houphouët-Boigny, ...
International Nuclear Information System (INIS)
Pokhozhaev, Stanislav I
2011-01-01
The notion of Riemann quasi-invariants is introduced and their applications to several conservation laws are considered. The case of nonisentropic flow of an ideal polytropic gas is analysed in detail. Sufficient conditions for gradient catastrophes are obtained. Bibliography: 16 titles.
Primavera Silenciosa de Rachel Carson,1962
Pinto-Correia, Teresa
2011-01-01
Esta comunicação, inserida no ciclo de conferências “Ambiente. Porquê ler os clássicos?” organizado pela Fundação Calouste Gulbenkian, apresenta uma reflexão sobre o livro “Primavera Silenciosa” (Silent Spring) de Rachel Carson, de 1962. Considerado como uma referência no imaginário ambiental da cultura contemporânea, este livro influenciou o pensamento social e político, pelo seu tema controverso e pela sua abordagem revolucionária, ao expor os efeitos dos pesticidas nos ecossistemas naturai...
International Nuclear Information System (INIS)
Arnlind, Joakim; Hofer, Laurent; Hoppe, Jens; Bordemann, Martin; Shimada, Hidehiko
2009-01-01
We introduce C-Algebras (quantum analogues of compact Riemann surfaces), defined by polynomial relations in non-commutative variables and containing a real parameter that, when taken to zero, provides a classical non-linear, Poisson-bracket, obtainable from a single polynomial C(onstraint) function. For a continuous class of quartic constraints, we explicitly work out finite dimensional representations of the corresponding C-Algebras.
The Rachel-B/coastal towing incident
International Nuclear Information System (INIS)
Fawn, D.R. Jr.
1990-01-01
On June 23, 1989, the outbound tanker ship Rachel-B and the towboat Gayolyn Ann Griffin, towing barges owned by Coastal Towing, collided in the northern end of the Houston Sip Channel near its confluence with the Bayport Channel. The collision resulted in a spill of approximately 6,000 barrels of slurry oil into upper Galveston Bay. This paper reports that the U.S. Coast Guard assumed the role of on-scene coordinator. Several State agencies were involved in the various on-site activities. The Texas Water Commission (TWC), as the State's lead agency in spill response, closely monitored the spill and cleanup activities. Despite the efforts of all the aforementioned agencies, the weather ultimately directed spill response activities as it became readily apparent that the eye of Tropical Storm Allison would pass near the site of the spill
Deformations of super Riemann surfaces
International Nuclear Information System (INIS)
Ninnemann, H.
1992-01-01
Two different approaches to (Konstant-Leites-) super Riemann surfaces are investigated. In the local approach, i.e. glueing open superdomains by superconformal transition functions, deformations of the superconformal structure are discussed. On the other hand, the representation of compact super Riemann surfaces of genus greater than one as a fundamental domain in the Poincare upper half-plane provides a simple description of super Laplace operators acting on automorphic p-forms. Considering purely odd deformations of super Riemann surfaces, the number of linear independent holomorphic sections of arbitrary holomorphic line bundles will be shown to be independent of the odd moduli, leading to a simple proof of the Riemann-Roch theorem for compact super Riemann surfaces. As a further consequence, the explicit connections between determinants of super Laplacians and Selberg's super zeta functions can be determined, allowing to calculate at least the 2-loop contribution to the fermionic string partition function. (orig.)
Deformations of super Riemann surfaces
Energy Technology Data Exchange (ETDEWEB)
Ninnemann, H [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik
1992-11-01
Two different approaches to (Konstant-Leites-) super Riemann surfaces are investigated. In the local approach, i.e. glueing open superdomains by superconformal transition functions, deformations of the superconformal structure are discussed. On the other hand, the representation of compact super Riemann surfaces of genus greater than one as a fundamental domain in the Poincare upper half-plane provides a simple description of super Laplace operators acting on automorphic p-forms. Considering purely odd deformations of super Riemann surfaces, the number of linear independent holomorphic sections of arbitrary holomorphic line bundles will be shown to be independent of the odd moduli, leading to a simple proof of the Riemann-Roch theorem for compact super Riemann surfaces. As a further consequence, the explicit connections between determinants of super Laplacians and Selberg's super zeta functions can be determined, allowing to calculate at least the 2-loop contribution to the fermionic string partition function. (orig.).
Comment on "Rachel Oliver's article on religion and environment"
Wardekker, J.A.|info:eu-repo/dai/nl/306644398
2008-01-01
I enjoyed reading Rachel Oliver's article on religion and environment. These differences (both between and within religions) in how people see the relation between mankind, nature and God are quite interesting indeed.
Glaucoma: Eye-to-Eye with Dr. Rachel Bishop
... of this page please turn JavaScript on. Feature: Glaucoma Eye-to-Eye with Dr. Rachel Bishop Past ... nerves are pale and cupped—signs of advanced glaucoma. Yet the patient wasn't aware of any ...
Detecting chlorinated hydrocarbon residues: Rachel Carson's villains.
Travis, Anthony S
2012-07-01
In 1962, Rachel Carson's Silent Spring drew the public's attention to the deleterious effects of chlorinated hydrocarbons employed as economic poisons in agriculture. However, she did not discuss how their residues could be routinely identified and quantified. In part, this was because the introduction of instruments for use in environmental analysis had only just begun, and she was probably unaware of their existence. The development of the instrumental methods began in industry, particularly at Dow and Shell, in the mid-1950s. Dow scientists, by combining mass spectrometry with gas chromatography, developed the most powerful technique, then and now, for the separation, quantitation and identification of chlorinated hydrocarbons. Shell scientists were no less innovative, particularly with the application of highly sensitive gas chromatography detectors to trace analysis. The first of these detectors, the electron capture detector, was invented by James Lovelock at the National Institute of Medical Research, North London, at the end of the 1950s. Around the same time, Dale Coulson in the USA developed his microcoulometric detector.
Conformal mapping on Riemann surfaces
Cohn, Harvey
2010-01-01
The subject matter loosely called ""Riemann surface theory"" has been the starting point for the development of topology, functional analysis, modern algebra, and any one of a dozen recent branches of mathematics; it is one of the most valuable bodies of knowledge within mathematics for a student to learn.Professor Cohn's lucid and insightful book presents an ideal coverage of the subject in five pans. Part I is a review of complex analysis analytic behavior, the Riemann sphere, geometric constructions, and presents (as a review) a microcosm of the course. The Riemann manifold is introduced in
Computational approach to Riemann surfaces
Klein, Christian
2011-01-01
This volume offers a well-structured overview of existent computational approaches to Riemann surfaces and those currently in development. The authors of the contributions represent the groups providing publically available numerical codes in this field. Thus this volume illustrates which software tools are available and how they can be used in practice. In addition examples for solutions to partial differential equations and in surface theory are presented. The intended audience of this book is twofold. It can be used as a textbook for a graduate course in numerics of Riemann surfaces, in which case the standard undergraduate background, i.e., calculus and linear algebra, is required. In particular, no knowledge of the theory of Riemann surfaces is expected; the necessary background in this theory is contained in the Introduction chapter. At the same time, this book is also intended for specialists in geometry and mathematical physics applying the theory of Riemann surfaces in their research. It is the first...
On Determinatives and the Category-Function Distinction: A Reply to Brett Reynolds
Lenchuk, Iryna; Ahmed, Amer
2014-01-01
This article examines the arguments made in the article "Determiners, Feline Marsupials, and the Category-Function Distinction: A Critique of ELT Grammars" by Brett Reynolds recently published in the "TESL Canada Journal" (2013). In our response, we demonstrate that the author's arguments are problematic on both…
Airpower Leadership on the Front Line: Lt Gen George H. Brett and Combat Command
2006-09-01
was assigned the additional duty of unit photographer and historian, bequeathing a photo album depicting his adventures to his oldest daughter.10 Lt...his fellow residents with piano music when the men were off duty.21 At the close of the war Brett was a temporary major and listed among officers who
Supermanifolds and super Riemann surfaces
International Nuclear Information System (INIS)
Rabin, J.M.
1986-09-01
The theory of super Riemann surfaces is rigorously developed using Rogers' theory of supermanifolds. The global structures of super Teichmueller space and super moduli space are determined. The super modular group is shown to be precisely the ordinary modular group. Super moduli space is shown to be the gauge-fixing slice for the fermionic string path integral
Opacity calculations for extreme physical systems: code RACHEL
Drska, Ladislav; Sinor, Milan
1996-08-01
Computer simulations of physical systems under extreme conditions (high density, temperature, etc.) require the availability of extensive sets of atomic data. This paper presents basic information on a self-consistent approach to calculations of radiative opacity, one of the key characteristics of such systems. After a short explanation of general concepts of the atomic physics of extreme systems, the structure of the opacity code RACHEL is discussed and some of its applications are presented.
Riemann surfaces with boundaries and string theory
International Nuclear Information System (INIS)
Morozov, A.Yu.; Roslyj, A.A.
1989-01-01
A consideration of the cutting and joining operations for Riemann surfaces permits one to express the functional integral on a Riemann surface in terms of integrals over its pieces which are suarfaces with boundaries. This yields an expression for the determinant of the Laplacian on a Riemann surface in terms of Krichever maps for its pieces. Possible applications of the methods proposed to a study of the string perturbation theory in terms of an universal moduli space are mentioned
The Riemann-Lovelock Curvature Tensor
Kastor, David
2012-01-01
In order to study the properties of Lovelock gravity theories in low dimensions, we define the kth-order Riemann-Lovelock tensor as a certain quantity having a total 4k-indices, which is kth-order in the Riemann curvature tensor and shares its basic algebraic and differential properties. We show that the kth-order Riemann-Lovelock tensor is determined by its traces in dimensions 2k \\le D
Exploring the Riemann zeta function 190 years from Riemann's birth
Nikeghbali, Ashkan; Rassias, Michael
2017-01-01
This book is concerned with the Riemann Zeta Function, its generalizations, and various applications to several scientific disciplines, including Analytic Number Theory, Harmonic Analysis, Complex Analysis and Probability Theory. Eminent experts in the field illustrate both old and new results towards the solution of long-standing problems and include key historical remarks. Offering a unified, self-contained treatment of broad and deep areas of research, this book will be an excellent tool for researchers and graduate students working in Mathematics, Mathematical Physics, Engineering and Cryptography.
Functionals of finite Riemann surfaces
Schiffer, Menahem
1954-01-01
This advanced monograph on finite Riemann surfaces, based on the authors' 1949-50 lectures at Princeton University, remains a fundamental book for graduate students. The Bulletin of the American Mathematical Society hailed the self-contained treatment as the source of ""a plethora of ideas, each interesting in its own right,"" noting that ""the patient reader will be richly rewarded."" Suitable for graduate-level courses, the text begins with three chapters that offer a development of the classical theory along historical lines, examining geometrical and physical considerations, existence theo
LFI Radiometric Chain Assembly (RCA) data handling ``Rachel''
Malaspina, M.; Franceschi, E.; Battaglia, P.; Binko, P.; Butler, R. C.; D'Arcangelo, O.; Fogliani, S.; Frailis, M.; Franceschet, C.; Galeotta, S.; Gasparo, F.; Gregorio, A.; Lapolla, M.; Leonardi, R.; Maggio, G.; Mandolesi, N.; Manzato, P.; Maris, M.; Meharga, M.; Meinhold, P.; Morisset, N.; Pasian, F.; Perrotta, F.; Rohlfs, R.; Sandri, M.; Tomasi, M.; Türler, M.; Zacchei, A.; Zonca, A.
2009-12-01
Planck's Low Frequency Instrument is an array of 22 pseudo-correlation radiometers at 30, 44, and 70 GHz. Before integrating the overall array assembly, a first set of tests has been performed for each radiometer chain assembly (RCA), consisting of two radiometers. In this paper, we describe Rachel, a software application which has been purposely developed and used during the RCA test campaign to carry out both near-realtime on-line data analysis and data storage (in FITS format) of the raw output from the radiometric chains.
LFI Radiometric Chain Assembly (RCA) data handling 'Rachel'
International Nuclear Information System (INIS)
Malaspina, M; Franceschi, E; Butler, R C; Mandolesi, N; Battaglia, P; Franceschet, C; Lapolla, M; Binko, P; Meharga, M; D'Arcangelo, O; Fogliani, S; Frailis, M; Galeotta, S; Gasparo, F; Maggio, G; Manzato, P; Maris, M; Gregorio, A; Leonardi, R; Meinhold, P
2009-01-01
Planck's Low Frequency Instrument is an array of 22 pseudo-correlation radiometers at 30, 44, and 70 GHz. Before integrating the overall array assembly, a first set of tests has been performed for each radiometer chain assembly (RCA), consisting of two radiometers. In this paper, we describe Rachel, a software application which has been purposely developed and used during the RCA test campaign to carry out both near-realtime on-line data analysis and data storage (in FITS format) of the raw output from the radiometric chains.
A Polyakov action on Riemann surfaces
International Nuclear Information System (INIS)
Zucchini, R.
1991-02-01
A calculation of the effective action for induced conformal gravity on higher genus Riemann surfaces is presented. Our expression, generalizing Polyakov's formula, depends holomorphically on the Beltrami and integrates the diffeomorphism anomaly. A solution of the conformal Ward identity on an arbitrary compact Riemann surfaces without boundary is presented, and its remarkable properties are studied. (K.A.) 16 refs., 2 figs
The Riemann-Lovelock curvature tensor
International Nuclear Information System (INIS)
Kastor, David
2012-01-01
In order to study the properties of Lovelock gravity theories in low dimensions, we define the kth-order Riemann-Lovelock tensor as a certain quantity having a total 4k-indices, which is kth order in the Riemann curvature tensor and shares its basic algebraic and differential properties. We show that the kth-order Riemann-Lovelock tensor is determined by its traces in dimensions 2k ≤ D < 4k. In D = 2k + 1 this identity implies that all solutions of pure kth-order Lovelock gravity are 'Riemann-Lovelock' flat. It is verified that the static, spherically symmetric solutions of these theories, which are missing solid angle spacetimes, indeed satisfy this flatness property. This generalizes results from Einstein gravity in D = 3, which corresponds to the k = 1 case. We speculate about some possible further consequences of Riemann-Lovelock curvature. (paper)
Women, Scientists, Agitators: Magazine Portrayal of Rachel Carson and Theo Colborn.
Corbett, Julia B.
2001-01-01
Utilizes a theoretical framework of the media's role in reporting conflict and uncertain science, and feminism and science in a thematic analysis of magazine coverage given Rachel Carson and "the Rachel Carson of '90s," Theo Colborn. Notes that Carson and Colborn's identities as women, scientists, and agitators led critics to charge that…
Directory of Open Access Journals (Sweden)
José Manuel Sánchez Muñoz
2011-10-01
Full Text Available En el mes de noviembre de 1859, durante la presentación mensual de losinformes de la Academia de Berlín, el alemán Bernhard Riemann presentóun trabajo que cambiaría los designios futuros de la ciencia matemática. El tema central de su informe se centraba en los números primos, presentando el que hoy día, una vez demostrada la Conjetura de Poincaré, puede ser considerado el problema matemático abierto más importante. El presente artículo muestra en su tercera sección una traducción al castellano de dicho trabajo.
Conformal algebra of Riemann surfaces
International Nuclear Information System (INIS)
Vafa, C.
1988-01-01
It has become clear over the last few years that 2-dimensional conformal field theories are a crucial ingredient of string theory. Conformal field theories correspond to vacuum solutions of strings; or more precisely we know how to compute string spectrum and scattering amplitudes by starting from a formal theory (with a proper value of central charge of the Virasoro algebra). Certain non-linear sigma models do give rise to conformal theories. A lot of progress has been made in the understanding of conformal theories. The author discusses a different view of conformal theories which was motivated by the development of operator formalism on Riemann surfaces. The author discusses an interesting recent work from this point of view
Super differential forms on super Riemann surfaces
International Nuclear Information System (INIS)
Konisi, Gaku; Takahasi, Wataru; Saito, Takesi.
1994-01-01
Line integral on the super Riemann surface is discussed. A 'super differential operator' which possesses both properties of differential and of differential operator is proposed. With this 'super differential operator' a new theory of differential form on the super Riemann surface is constructed. We call 'the new differentials on the super Riemann surface' 'the super differentials'. As the applications of our theory, the existency theorems of singular 'super differentials' such as 'super abelian differentials of the 3rd kind' and of a super projective connection are examined. (author)
A Mole's Eye View: Marcellus as Mosaic by Rachel Sager
Sager, R.
2013-12-01
I am an artist living and working in the energy vortex of Southwestern Pennsylvania and am watching great upheaval, both good and bad, happen to my land and its citizens due to the phenomenon caused by our particular geologic formation; the Marcellus Shale. My work embraces the earth itself through the medium of mosaic, and I have found it to be a great communicator to many groups of people: landowners, gas industry workers, environmentalists. I tell the story of how I came to be so dependent on my native stone, coming from a long line of coal miners and farmers who taught me to be aware of what lies beneath my feet. With my stone hammer, I chop up shale, sandstone, limestone, and coal, transforming it into tiny, expressive pieces that tell stories and help people to grasp geologic concepts that can otherwise be overwhelming and mysterious. I address the industry itself by representing the controversial enterprise of fracking, but also delve intimately into building relationships with the stone that I gather, wash, categorize, cut, and lay into mortar. By depicting these layers of earth, I am building touchable, organic images of geologic time that are highly accessible to the human brain and sensibility. There is something personal and immediate about standing in front of one of these mosaics, being able to touch it that gives the viewer power over an idea that often leaves them feeling in the dark. As a classically trained mosaic artist, I bring back the skills, culture, and tradition of a Euro-centered art form and weave it into my North American geology. Through a highly detailed and dynamic PowerPoint presentation of my work, I help people to see the earth beneath their feet with new eyes. Rachel Sager, artist www.rachelsagermosaics.com Contemporary Art in a Geologic Medium: Rachel Sager Mosaics
Lectures on the Riemann zeta function
Iwaniec, H
2014-01-01
The Riemann zeta function was introduced by L. Euler (1737) in connection with questions about the distribution of prime numbers. Later, B. Riemann (1859) derived deeper results about the prime numbers by considering the zeta function in the complex variable. The famous Riemann Hypothesis, asserting that all of the non-trivial zeros of zeta are on a critical line in the complex plane, is one of the most important unsolved problems in modern mathematics. The present book consists of two parts. The first part covers classical material about the zeros of the Riemann zeta function with applications to the distribution of prime numbers, including those made by Riemann himself, F. Carlson, and Hardy-Littlewood. The second part gives a complete presentation of Levinson's method for zeros on the critical line, which allows one to prove, in particular, that more than one-third of non-trivial zeros of zeta are on the critical line. This approach and some results concerning integrals of Dirichlet polynomials are new. Th...
Silent Spring, the 50th anniversary of Rachel Carson's book.
Pimentel, David
2012-09-27
David Pimentel is a professor of ecology and agricultural sciences at Cornell University, Ithaca, NY 14853-0901. His Ph.D. is from Cornell University and had postdoctoral research at the University of Chicago, MIT, and fellowship at Oxford University (England). He was awarded a distinguished honorary degree from the University of Massachusetts. His research spans the fields of energy, population ecology, biological pest control, pesticides, sustainable agriculture, land and water conservation, livestock, and environmental policy. Pimentel has published more than 700 scientific papers and 37 books and has served on many national and government committees including the National Academy of Sciences; President's Science Advisory Council; U.S Department of Agriculture; U.S. Department of Energy; U.S. Department of Health, Education and Welfare; Office of Technology Assessment of the U.S. Congress; and the U.S. State Department. He is currently Editorial Advisor for BMC Ecology. In this article, he reflects on 50 years since the publication of Rachel Carson's influential book, Silent Spring.
Quantum Hall effect on Riemann surfaces
Tejero Prieto, Carlos
2009-06-01
We study the family of Landau Hamiltonians compatible with a magnetic field on a Riemann surface S by means of Fourier-Mukai and Nahm transforms. Starting from the geometric formulation of adiabatic charge transport on Riemann surfaces, we prove that Hall conductivity is proportional to the intersection product on the first homology group of S and therefore it is quantized. Finally, by using the theory of determinant bundles developed by Bismut, Gillet and Soul, we compute the adiabatic curvature of the spectral bundles defined by the holomorphic Landau levels. We prove that it is given by the polarization of the jacobian variety of the Riemann surface, plus a term depending on the relative analytic torsion.
Quantum Hall effect on Riemann surfaces
International Nuclear Information System (INIS)
Tejero Prieto, Carlos
2009-01-01
We study the family of Landau Hamiltonians compatible with a magnetic field on a Riemann surface S by means of Fourier-Mukai and Nahm transforms. Starting from the geometric formulation of adiabatic charge transport on Riemann surfaces, we prove that Hall conductivity is proportional to the intersection product on the first homology group of S and therefore it is quantized. Finally, by using the theory of determinant bundles developed by Bismut, Gillet and Soul, we compute the adiabatic curvature of the spectral bundles defined by the holomorphic Landau levels. We prove that it is given by the polarization of the jacobian variety of the Riemann surface, plus a term depending on the relative analytic torsion.
The Rachel Carson Letters and the Making of Silent Spring
Directory of Open Access Journals (Sweden)
John Paull
2013-06-01
Full Text Available Environment, conservation, green, and kindred movements look back to Rachel Carson’s 1962 book Silent Spring as a milestone. The impact of the book, including on government, industry, and civil society, was immediate and substantial, and has been extensively described; however, the provenance of the book has been less thoroughly examined. Using Carson’s personal correspondence, this paper reveals that the primary source for Carson’s book was the extensive evidence and contacts compiled by two biodynamic farmers, Marjorie Spock and Mary T. Richards, of Long Island, New York. Their evidence was compiled for a suite of legal actions (1957-1960 against the U.S. Government and that contested the aerial spraying of dichlorodiphenyltrichloroethane (DDT. During Rudolf Steiner’s lifetime, Spock and Richards both studied at Steiner’s Goetheanum, the headquarters of Anthroposophy, located in Dornach, Switzerland. Spock and Richards were prominent U.S. anthroposophists, and established a biodynamic farm under the tutelage of the leading biodynamics exponent of the time, Dr. Ehrenfried Pfeiffer. When their property was under threat from a government program of DDT spraying, they brought their case, eventually lost it, in the process spent US$100,000, and compiled the evidence that they then shared with Carson, who used it, and their extensive contacts and the trial transcripts, as the primary input for Silent Spring. Carson attributed to Spock, Richards, and Pfeiffer, no credit whatsoever in her book. As a consequence, the organics movement has not received the recognition, that is its due, as the primary impulse for Silent Spring, and it is, itself, unaware of this provenance.
Chiral bosonization on a Riemann surface
International Nuclear Information System (INIS)
Eguchi, Tohru; Ooguri, Hirosi
1987-01-01
We point out that the basic addition theorem of θ-functions, Fay's identity, implies an equivalence between bosons and chiral fermions on Riemann surfaces with arbitrary genus. We present a rule for a bosonized calculation of correlation functions. We also discuss ghost systems of n and (1-n) tensors and derive formulas for their chiral determinants. (orig.)
Gaussian curvature on hyperelliptic Riemann surfaces
Indian Academy of Sciences (India)
Indian Acad. Sci. (Math. Sci.) Vol. 124, No. 2, May 2014, pp. 155–167. c Indian Academy of Sciences. Gaussian curvature on hyperelliptic Riemann surfaces. ABEL CASTORENA. Centro de Ciencias Matemáticas (Universidad Nacional Autónoma de México,. Campus Morelia) Apdo. Postal 61-3 Xangari, C.P. 58089 Morelia,.
Conformal deformation of Riemann space and torsion
International Nuclear Information System (INIS)
Pyzh, V.M.
1981-01-01
Method for investigating conformal deformations of Riemann spaces using torsion tensor, which permits to reduce the second ' order equations for Killing vectors to the system of the first order equations, is presented. The method is illustrated using conformal deformations of dimer sphere as an example. A possibility of its use when studying more complex deformations is discussed [ru
Study Paths, Riemann Surfaces, and Strebel Differentials
Buser, Peter; Semmler, Klaus-Dieter
2017-01-01
These pages aim to explain and interpret why the late Mika Seppälä, a conformal geometer, proposed to model student study behaviour using concepts from conformal geometry, such as Riemann surfaces and Strebel differentials. Over many years Mika Seppälä taught online calculus courses to students at Florida State University in the United States, as…
Hysteresis rarefaction in the Riemann problem
Czech Academy of Sciences Publication Activity Database
Krejčí, Pavel
2008-01-01
Roč. 138, - (2008), s. 1-10 ISSN 1742-6588. [International Workshop on Multi-Rate Processes and Hysteresis. Cork , 31.03.2008-05.04.2008] Institutional research plan: CEZ:AV0Z10190503 Keywords : Preisach hysteresis * Riemann problem Subject RIV: BA - General Mathematics http://iopscience.iop.org/1742-6596/138/1/012010
Generalized Riemann problem for reactive flows
International Nuclear Information System (INIS)
Ben-Artzi, M.
1989-01-01
A generalized Riemann problem is introduced for the equations of reactive non-viscous compressible flow in one space dimension. Initial data are assumed to be linearly distributed on both sides of a jump discontinuity. The resolution of the singularity is studied and the first-order variation (in time) of flow variables is given in exact form. copyright 1989 Academic Press, Inc
On Lovelock analogs of the Riemann tensor
Camanho, Xián O.; Dadhich, Naresh
2016-03-01
It is possible to define an analog of the Riemann tensor for Nth order Lovelock gravity, its characterizing property being that the trace of its Bianchi derivative yields the corresponding analog of the Einstein tensor. Interestingly there exist two parallel but distinct such analogs and the main purpose of this note is to reconcile both formulations. In addition we will introduce a simple tensor identity and use it to show that any pure Lovelock vacuum in odd d=2N+1 dimensions is Lovelock flat, i.e. any vacuum solution of the theory has vanishing Lovelock-Riemann tensor. Further, in the presence of cosmological constant it is the Lovelock-Weyl tensor that vanishes.
The KZB equations on Riemann surfaces
Felder, Giovanni
1996-01-01
In this paper, based on the author's lectures at the 1995 les Houches Summer school, explicit expressions for the Friedan--Shenker connection on the vector bundle of WZW conformal blocks on the moduli space of curves with tangent vectors at $n$ marked points are given. The covariant derivatives are expressed in terms of ``dynamical $r$-matrices'', a notion borrowed from integrable systems. The case of marked points moving on a fixed Riemann surface is studied more closely. We prove a universa...
Post-Quantum Cryptography: Riemann Primitives and Chrysalis
Malloy, Ian; Hollenbeck, Dennis
2018-01-01
The Chrysalis project is a proposed method for post-quantum cryptography using the Riemann sphere. To this end, Riemann primitives are introduced in addition to a novel implementation of this new method. Chrysalis itself is the first cryptographic scheme to rely on Holomorphic Learning with Errors, which is a complex form of Learning with Errors relying on the Gauss Circle Problem within the Riemann sphere. The principle security reduction proposed by this novel cryptographic scheme applies c...
Operator bosonization on Riemann surfaces: new vertex operators
International Nuclear Information System (INIS)
Semikhatov, A.M.
1989-01-01
A new formalism is proposed for the construction of an operator theory of generalized ghost systems (bc theories of spin J) on Riemann surfaces (loop diagrams of the theory of closed strings). The operators of the bc system are expressed in terms of operators of the bosonic conformal theory on a Riemann surface. In contrast to the standard bosonization formulas, which have meaning only locally, operator Baker-Akhiezer functions, which are well defined globally on a Riemann surface of arbitrary genus, are introduced. The operator algebra of the Baker-Akhiezer functions generates explicitly the algebraic-geometric τ function and correlation functions of bc systems on Riemann surfaces
Vandergrift, Larry; Cross, Jeremy
2017-01-01
Most recent publications related to listening comprehension research deal with listening strategy instruction, metacognitive instruction or multimedia applications. This paper discusses one study from each of these three domains--Graham & Macaro (2008), Vandergrift & Tafaghodtari (2010) and Brett (1997)--and presents the need and…
The concept of a Riemann surface
Weyl, Hermann
2009-01-01
This classic on the general history of functions was written by one of the twentieth century's best-known mathematicians. Hermann Weyl, who worked with Einstein at Princeton, combined function theory and geometry in this high-level landmark work, forming a new branch of mathematics and the basis of the modern approach to analysis, geometry, and topology.The author intended this book not only to develop the basic ideas of Riemann's theory of algebraic functions and their integrals but also to examine the related ideas and theorems with an unprecedented degree of rigor. Weyl's two-part treatment
Riemann monodromy problem and conformal field theories
International Nuclear Information System (INIS)
Blok, B.
1989-01-01
A systematic analysis of the use of the Riemann monodromy problem for determining correlators (conformal blocks) on the sphere is presented. The monodromy data is constructed in terms of the braid matrices and gives a constraint on the noninteger part of the conformal dimensions of the primary fields. To determine the conformal blocks we need to know the order of singularities. We establish a criterion which tells us when the knowledge of the conformal dimensions of primary fields suffice to determine the blocks. When zero modes of the extended algebra are present the analysis is more difficult. In this case we give a conjecture that works for the SU(2) WZW case. (orig.)
Quantum field theory on higher-genus Riemann surfaces
International Nuclear Information System (INIS)
Kubo, Reijiro; Yoshii, Hisahiro; Ojima, Shuichi; Paul, S.K.
1989-07-01
Quantum field theory for b-c systems is formulated on Riemann surfaces with arbitrary genus. We make use of the formalism recently developed by Krichever and Novikov. Hamiltonian is defined properly, and the Ward-Takahashi identities are derived on higher-genus Riemann surfaces. (author)
Non-abelian bosonization in higher genus Riemann surfaces
International Nuclear Information System (INIS)
Koh, I.G.; Yu, M.
1988-01-01
We propose a generalization of the character formulas of the SU(2) Kac-Moody algebra to higher genus Riemann surfaces. With this construction, we show that the modular invariant partition funciton of the SO(4) k = 1 Wess-Zumino model is equivalent, in arbitrary genus Riemann surfaces, to that of free fermion theory. (orig.)
Collisionless analogs of Riemann S ellipsoids with halo
International Nuclear Information System (INIS)
Abramyan, M.G.
1987-01-01
A spheroidal halo ensures equilibrium of the collisionless analogs of the Riemann S ellipsoids with oscillations of the particles along the direction of their rotation. Sequences of collisionless triaxial ellipsoids begin and end with dynamically stable members of collisionless embedded spheroids. Both liquid and collisionless Riemann S ellipsoids with weak halo have properties that resemble those of bars of SB galaxies
A Riemann problem with small viscosity and dispersion
Directory of Open Access Journals (Sweden)
Kayyunnapara Thomas Joseph
2006-09-01
Full Text Available In this paper we prove existence of global solutions to a hyperbolic system in elastodynamics, with small viscosity and dispersion terms and derive estimates uniform in the viscosity-dispersion parameters. By passing to the limit, we prove the existence of solution the Riemann problem for the hyperbolic system with arbitrary Riemann data.
Getting superstring amplitudes by degenerating Riemann surfaces
International Nuclear Information System (INIS)
Matone, Marco; Volpato, Roberto
2010-01-01
We explicitly show how the chiral superstring amplitudes can be obtained through factorisation of the higher genus chiral measure induced by suitable degenerations of Riemann surfaces. This powerful tool also allows to derive, at any genera, consistency relations involving the amplitudes and the measure. A key point concerns the choice of the local coordinate at the node on degenerate Riemann surfaces that greatly simplifies the computations. As a first application, starting from recent ansaetze for the chiral measure up to genus five, we compute the chiral two-point function for massless Neveu-Schwarz states at genus two, three and four. For genus higher than three, these computations include some new corrections to the conjectural formulae appeared so far in the literature. After GSO projection, the two-point function vanishes at genus two and three, as expected from space-time supersymmetry arguments, but not at genus four. This suggests that the ansatz for the superstring measure should be corrected for genus higher than four.
Ice cream and orbifold Riemann-Roch
International Nuclear Information System (INIS)
Buckley, Anita; Reid, Miles; Zhou Shengtian
2013-01-01
We give an orbifold Riemann-Roch formula in closed form for the Hilbert series of a quasismooth polarized n-fold (X,D), under the assumption that X is projectively Gorenstein with only isolated orbifold points. Our formula is a sum of parts each of which is integral and Gorenstein symmetric of the same canonical weight; the orbifold parts are called ice cream functions. This form of the Hilbert series is particularly useful for computer algebra, and we illustrate it on examples of K3 surfaces and Calabi-Yau 3-folds. These results apply also with higher dimensional orbifold strata (see [1] and [2]), although the precise statements are considerably trickier. We expect to return to this in future publications.
E-string theory on Riemann surfaces
Energy Technology Data Exchange (ETDEWEB)
Kim, Hee-Cheol; Vafa, Cumrun [Jefferson Physical Laboratory, Harvard University, Cambridge, MA (United States); Razamat, Shlomo S. [Physics Department, Technion, Haifa (Israel); Zafrir, Gabi [Kavli IPMU (WPI), UTIAS, the University of Tokyo, Kashiwa, Chiba (Japan)
2018-01-15
We study compactifications of the 6d E-string theory, the theory of a small E{sub 8} instanton, to four dimensions. In particular we identify N = 1 field theories in four dimensions corresponding to compactifications on arbitrary Riemann surfaces with punctures and with arbitrary non-abelian flat connections as well as fluxes for the abelian sub-groups of the E{sub 8} flavor symmetry. This sheds light on emergent symmetries in a number of 4d N = 1 SCFTs (including the 'E7 surprise' theory) as well as leads to new predictions for a large number of 4-dimensional exceptional dualities and symmetries. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Moduli of Riemann surfaces, transcendental aspects
International Nuclear Information System (INIS)
Hain, R.
2000-01-01
These notes are an informal introduction to moduli spaces of compact Riemann surfaces via complex analysis, topology and Hodge Theory. The prerequisites for the first lecture are just basic complex variables, basic Riemann surface theory up to at least the Riemann-Roch formula, and some algebraic topology, especially covering space theory. The first lecture covers moduli in genus 0 and genus 1 as these can be understood using relatively elementary methods, but illustrate many of the points which arise in higher genus. The notes cover more material than was covered in the lectures, and sometimes the order of topics in the notes differs from that in the lectures. We have seen in genus 1 case that M 1 is the quotient Γ 1 /X 1 of a contractible complex manifold X 1 = H by a discrete group Γ 1 = SL 2 (Z). The action of Γ 1 on X 1 is said to be virtually free - that is, Γ 1 has a finite index subgroup which acts (fixed point) freely on X 1 . In this section we will generalize this to all g >= 1 - we will sketch a proof that there is a contractible complex manifold Xg, called Teichmueller space, and a group Γ g , called the mapping class group, which acts virtually freely on X g . The moduli space of genus g compact Riemann surfaces is the quotient: M g = Γ g /X g . This will imply that M g has the structure of a complex analytic variety with finite quotient singularities. Teichmueller theory is a difficult and technical subject. Because of this, it is only possible to give an overview. In this lecture, we compute the orbifold Picard group of M g for all g >= 1. Recall that an orbifold line bundle over M g is a holomorphic line bundle L over Teichmueller space X g together with an action of the mapping class group Γ g on it such that the projection L → X g is Γ g -equivariant. An orbifold section of this line bundle is a holomorphic Γ g -equivariant section X g → L of L. This is easily seen to be equivalent to fixing a level l>= 3 and considering holomorphic
Transformation optics with artificial Riemann sheets
Xu, Lin; Chen, Huanyang
2013-11-01
The two original versions of ‘invisibility’ cloaks (Leonhardt 2006 Science 312 1777-80 and Pendry et al 2006 Science 312 1780-2) show perfect cloaking but require unphysical singularities in material properties. A non-Euclidean version of cloaking (Leonhardt 2009 Science 323 110-12) was later presented to address these problems, using a very complicated non-Euclidean geometry. In this work, we combine the two original approaches to transformation optics into a more general concept: transformation optics with artificial Riemann sheets. Our method is straightforward and can be utilized to design new kinds of cloaks that can work not only in the realm of geometric optics but also using wave optics. The physics behind this design is similar to that of the conformal cloak for waves. The resonances in the interior region make the phase delay disappear and induce the cloaking effect. Numerical simulations confirm our theoretical results.
Transformation optics with artificial Riemann sheets
International Nuclear Information System (INIS)
Xu, Lin; Chen, Huanyang
2013-01-01
The two original versions of ‘invisibility’ cloaks (Leonhardt 2006 Science 312 1777–80 and Pendry et al 2006 Science 312 1780–2) show perfect cloaking but require unphysical singularities in material properties. A non-Euclidean version of cloaking (Leonhardt 2009 Science 323 110–12) was later presented to address these problems, using a very complicated non-Euclidean geometry. In this work, we combine the two original approaches to transformation optics into a more general concept: transformation optics with artificial Riemann sheets. Our method is straightforward and can be utilized to design new kinds of cloaks that can work not only in the realm of geometric optics but also using wave optics. The physics behind this design is similar to that of the conformal cloak for waves. The resonances in the interior region make the phase delay disappear and induce the cloaking effect. Numerical simulations confirm our theoretical results. (paper)
Ice cream and orbifold Riemann-Roch
Buckley, Anita; Reid, Miles; Zhou, Shengtian
2013-06-01
We give an orbifold Riemann-Roch formula in closed form for the Hilbert series of a quasismooth polarized n-fold (X,D), under the assumption that X is projectively Gorenstein with only isolated orbifold points. Our formula is a sum of parts each of which is integral and Gorenstein symmetric of the same canonical weight; the orbifold parts are called ice cream functions. This form of the Hilbert series is particularly useful for computer algebra, and we illustrate it on examples of {K3} surfaces and Calabi-Yau 3-folds. These results apply also with higher dimensional orbifold strata (see [1] and [2]), although the precise statements are considerably trickier. We expect to return to this in future publications.
From Riemann to differential geometry and relativity
Papadopoulos, Athanase; Yamada, Sumio
2017-01-01
This book explores the work of Bernhard Riemann and its impact on mathematics, philosophy and physics. It features contributions from a range of fields, historical expositions, and selected research articles that were motivated by Riemann’s ideas and demonstrate their timelessness. The editors are convinced of the tremendous value of going into Riemann’s work in depth, investigating his original ideas, integrating them into a broader perspective, and establishing ties with modern science and philosophy. Accordingly, the contributors to this volume are mathematicians, physicists, philosophers and historians of science. The book offers a unique resource for students and researchers in the fields of mathematics, physics and philosophy, historians of science, and more generally to a wide range of readers interested in the history of ideas.
Interpolating and sampling sequences in finite Riemann surfaces
Ortega-Cerda, Joaquim
2007-01-01
We provide a description of the interpolating and sampling sequences on a space of holomorphic functions on a finite Riemann surface, where a uniform growth restriction is imposed on the holomorphic functions.
Two-dimensional time dependent Riemann solvers for neutron transport
International Nuclear Information System (INIS)
Brunner, Thomas A.; Holloway, James Paul
2005-01-01
A two-dimensional Riemann solver is developed for the spherical harmonics approximation to the time dependent neutron transport equation. The eigenstructure of the resulting equations is explored, giving insight into both the spherical harmonics approximation and the Riemann solver. The classic Roe-type Riemann solver used here was developed for one-dimensional problems, but can be used in multidimensional problems by treating each face of a two-dimensional computation cell in a locally one-dimensional way. Several test problems are used to explore the capabilities of both the Riemann solver and the spherical harmonics approximation. The numerical solution for a simple line source problem is compared to the analytic solution to both the P 1 equation and the full transport solution. A lattice problem is used to test the method on a more challenging problem
The exchange algebra for Liouville theory on punctured Riemann sphere
International Nuclear Information System (INIS)
Shen Jianmin; Sheng Zhengmao
1991-11-01
We consider in this paper the classical Liouville field theory on the Riemann sphere with n punctures. In terms of the uniformization theorem of Riemann surface, we show explicitly the classical exchange algebra (CEA) for the chiral components of the Liouville fields. We find that the matrice which dominate the CEA is related to the symmetry of the Lie group SL(n) in a nontrivial manner with n>3. (author). 10 refs
Meromorphic functions and cohomology on a Riemann surface
International Nuclear Information System (INIS)
Gomez-Mont, X.
1989-01-01
The objective of this set of notes is to introduce a series of concepts of Complex Analytic Geometry on a Riemann Surface. We motivate the introduction of cohomology groups through the analysis of meromorphic functions. We finish by showing that the set of infinitesimal deformations of a Riemann surface (the tangent space to Teichmueller space) may be computed as a Cohomology group. (author). 6 refs
Robinson manifolds and Cauchy-Riemann spaces
Trautman, A
2002-01-01
A Robinson manifold is defined as a Lorentz manifold (M, g) of dimension 2n >= 4 with a bundle N subset of C centre dot TM such that the fibres of N are maximal totally null and there holds the integrability condition [Sec N, Sec N] subset of Sec N. The real part of N intersection N-bar is a bundle of null directions tangent to a congruence of null geodesics. This generalizes the notion of a shear-free congruence of null geodesics (SNG) in dimension 4. Under a natural regularity assumption, the set M of all these geodesics has the structure of a Cauchy-Riemann manifold of dimension 2n - 1. Conversely, every such CR manifold lifts to many Robinson manifolds. Three definitions of a CR manifold are described here in considerable detail; they are equivalent under the assumption of real analyticity, but not in the smooth category. The distinctions between these definitions have a bearing on the validity of the Robinson theorem on the existence of null Maxwell fields associated with SNGs. This paper is largely a re...
Milstein Rachel, La Bible dans l’art islamique, Paris, PUF, 2005, 155 p.
Directory of Open Access Journals (Sweden)
Valérie Gonzalez
2008-04-01
Full Text Available Inépuisable et fascinant sujet d’étude, l’art du livre dans les pays musulmans ne laisse pas de susciter de nouvelles approches, méthodes d’analyse et procédures de classification. L’un des aspects scientifiques essentiels de ce domaine reste évidement l’iconologie, laquelle constitue le cadre de travail de Rachel Milstein dans son dernier ouvrage, La Bible dans l’art islamique. L’auteure y expose l’ensemble des manuscrits enluminés islamiques depuis les débuts jusqu’à nos jours sous un de se...
African Journals Online (AJOL)
different types of victims. Asked about motivations, men indicated that rape most commonly stemmed ... media campaigns such as 'Brothers for Life' and. 'One Man Can'. ..... of socialisation into a very violent, accentuated masculinity of a type.
Balsara, Dinshaw S.; Nkonga, Boniface
2017-10-01
Just as the quality of a one-dimensional approximate Riemann solver is improved by the inclusion of internal sub-structure, the quality of a multidimensional Riemann solver is also similarly improved. Such multidimensional Riemann problems arise when multiple states come together at the vertex of a mesh. The interaction of the resulting one-dimensional Riemann problems gives rise to a strongly-interacting state. We wish to endow this strongly-interacting state with physically-motivated sub-structure. The fastest way of endowing such sub-structure consists of making a multidimensional extension of the HLLI Riemann solver for hyperbolic conservation laws. Presenting such a multidimensional analogue of the HLLI Riemann solver with linear sub-structure for use on structured meshes is the goal of this work. The multidimensional MuSIC Riemann solver documented here is universal in the sense that it can be applied to any hyperbolic conservation law. The multidimensional Riemann solver is made to be consistent with constraints that emerge naturally from the Galerkin projection of the self-similar states within the wave model. When the full eigenstructure in both directions is used in the present Riemann solver, it becomes a complete Riemann solver in a multidimensional sense. I.e., all the intermediate waves are represented in the multidimensional wave model. The work also presents, for the very first time, an important analysis of the dissipation characteristics of multidimensional Riemann solvers. The present Riemann solver results in the most efficient implementation of a multidimensional Riemann solver with sub-structure. Because it preserves stationary linearly degenerate waves, it might also help with well-balancing. Implementation-related details are presented in pointwise fashion for the one-dimensional HLLI Riemann solver as well as the multidimensional MuSIC Riemann solver.
Solution of Riemann problem for ideal polytropic dusty gas
International Nuclear Information System (INIS)
Nath, Triloki; Gupta, R.K.; Singh, L.P.
2017-01-01
Highlights : • A direct approach is used to solve the Riemann problem for dusty ideal polytropic gas. • An analytical solution to the Riemann problem for dusty gas flow is obtained. • The existence and uniqueness of the solution in dusty gas is discussed. • Properties of elementary wave solutions of Riemann problem are discussed. • Effect of mass fraction of solid particles on the solution is presented. - Abstract: The Riemann problem for a quasilinear hyperbolic system of equations governing the one dimensional unsteady flow of an ideal polytropic gas with dust particles is solved analytically without any restriction on magnitude of the initial states. The elementary wave solutions of the Riemann problem, that is shock waves, rarefaction waves and contact discontinuities are derived explicitly and their properties are discussed, for a dusty gas. The existence and uniqueness of the solution for Riemann problem in dusty gas is discussed. Also the conditions leading to the existence of shock waves or simple waves for a 1-family and 3-family curves in the solution of the Riemann problem are discussed. It is observed that the presence of dust particles in an ideal polytropic gas leads to more complex expression as compared to the corresponding ideal case; however all the parallel results remain same. Also, the effect of variation of mass fraction of dust particles with fixed volume fraction (Z) and the ratio of specific heat of the solid particles and the specific heat of the gas at constant pressure on the variation of velocity and density across the shock wave, rarefaction wave and contact discontinuities are discussed.
Riemann solvers and undercompressive shocks of convex FPU chains
International Nuclear Information System (INIS)
Herrmann, Michael; Rademacher, Jens D M
2010-01-01
We consider FPU-type atomic chains with general convex potentials. The naive continuum limit in the hyperbolic space–time scaling is the p-system of mass and momentum conservation. We systematically compare Riemann solutions to the p-system with numerical solutions to discrete Riemann problems in FPU chains, and argue that the latter can be described by modified p-system Riemann solvers. We allow the flux to have a turning point, and observe a third type of elementary wave (conservative shocks) in the atomistic simulations. These waves are heteroclinic travelling waves and correspond to non-classical, undercompressive shocks of the p-system. We analyse such shocks for fluxes with one or more turning points. Depending on the convexity properties of the flux we propose FPU-Riemann solvers. Our numerical simulations confirm that Lax shocks are replaced by so-called dispersive shocks. For convex–concave flux we provide numerical evidence that convex FPU chains follow the p-system in generating conservative shocks that are supersonic. For concave–convex flux, however, the conservative shocks of the p-system are subsonic and do not appear in FPU-Riemann solutions
Riemann surfaces, Clifford algebras and infinite dimensional groups
International Nuclear Information System (INIS)
Carey, A.L.; Eastwood, M.G.; Hannabuss, K.C.
1990-01-01
We introduce of class of Riemann surfaces which possess a fixed point free involution and line bundles over these surfaces with which we can associate an infinite dimensional Clifford algebra. Acting by automorphisms of this algebra is a 'gauge' group of meromorphic functions on the Riemann surface. There is a natural Fock representation of the Clifford algebra and an associated projective representation of this group of meromorphic functions in close analogy with the construction of the basic representation of Kac-Moody algebras via a Fock representation of the Fermion algebra. In the genus one case we find a form of vertex operator construction which allows us to prove a version of the Boson-Fermion correspondence. These results are motivated by the analysis of soliton solutions of the Landau-Lifshitz equation and are rather distinct from recent developments in quantum field theory on Riemann surfaces. (orig.)
BRST quantization of superconformal theories on higher genus Riemann surfaces
International Nuclear Information System (INIS)
Leman Kuang
1992-01-01
A complex contour integral method is constructed and applied to the Becchi-Rouet-Stora-Tyutin (BRST) quantization procedure of string theories on higher genus Riemann surfaces with N=0 and 1 Krichever-Novikov (KN) algebras. This method makes calculations very simple. It is shown that the critical spacetime dimension of the string theories on a genus-g Riemann surface equals that of the string theories on a genus-zero Riemann surface, and that the 'Regge intercepts' in the genus-g case are α(g)=1-3/4g-9/8g 2 and 1/2-3/4g-17/16g 2 for bosonic strings and superstrings, respectively. (orig.)
Compact Riemann surfaces an introduction to contemporary mathematics
Jost, Jürgen
2006-01-01
Although Riemann surfaces are a time-honoured field, this book is novel in its broad perspective that systematically explores the connection with other fields of mathematics. It can serve as an introduction to contemporary mathematics as a whole as it develops background material from algebraic topology, differential geometry, the calculus of variations, elliptic PDE, and algebraic geometry. It is unique among textbooks on Riemann surfaces in including an introduction to Teichmüller theory. For this new edition, the author has expanded and rewritten several sections to include additional material and to improve the presentation.
The sewing technique and correlation functions on arbitrary Riemann surfaces
International Nuclear Information System (INIS)
Di Vecchia, P.
1989-01-01
We describe in the case of free bosonic and fermionic theories the sewing procedure, that is a very convenient way for constructing correlation functions of these theories on an arbitrary Riemann surface from their knowledge on the sphere. The fundamental object that results from this construction is the N-point g-loop vertex. It summarizes the information of all correlation functions of the theory on an arbitrary Riemann surface. We then check explicitly the bosonization rules and derive some useful formulas. (orig.)
Line operators from M-branes on compact Riemann surfaces
Energy Technology Data Exchange (ETDEWEB)
Amariti, Antonio [Physics Department, The City College of the CUNY, 160 Convent Avenue, New York, NY 10031 (United States); Orlando, Domenico [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland); Reffert, Susanne, E-mail: sreffert@itp.unibe.ch [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland)
2016-12-15
In this paper, we determine the charge lattice of mutually local Wilson and 't Hooft line operators for class S theories living on M5-branes wrapped on compact Riemann surfaces. The main ingredients of our analysis are the fundamental group of the N-cover of the Riemann surface, and a quantum constraint on the six-dimensional theory. The latter plays a central role in excluding some of the possible lattices and imposing consistency conditions on the charges. This construction gives a geometric explanation for the mutual locality among the lines, fixing their charge lattice and the structure of the four-dimensional gauge group.
On Riemann zeroes, lognormal multiplicative chaos, and Selberg integral
International Nuclear Information System (INIS)
Ostrovsky, Dmitry
2016-01-01
Rescaled Mellin-type transforms of the exponential functional of the Bourgade–Kuan–Rodgers statistic of Riemann zeroes are conjecturally related to the distribution of the total mass of the limit lognormal stochastic measure of Mandelbrot–Bacry–Muzy. The conjecture implies that a non-trivial, log-infinitely divisible probability distribution is associated with Riemann zeroes. For application, integral moments, covariance structure, multiscaling spectrum, and asymptotics associated with the exponential functional are computed in closed form using the known meromorphic extension of the Selberg integral. (paper)
Riemann zeta function from wave-packet dynamics
DEFF Research Database (Denmark)
Mack, R.; Dahl, Jens Peder; Moya-Cessa, H.
2010-01-01
We show that the time evolution of a thermal phase state of an anharmonic oscillator with logarithmic energy spectrum is intimately connected to the generalized Riemann zeta function zeta(s, a). Indeed, the autocorrelation function at a time t is determined by zeta (sigma + i tau, a), where sigma...... index of JWKB. We compare and contrast exact and approximate eigenvalues of purely logarithmic potentials. Moreover, we use a numerical method to find a potential which leads to exact logarithmic eigenvalues. We discuss possible realizations of Riemann zeta wave-packet dynamics using cold atoms...
Martin, N.
2015-01-01
This reading of Rachel Lichtenstein and Iain Sinclair’s Rodinsky’s Room (1999) accentuates the tensions within their collaborative work to explore how the text produces alternative versions of the spectral within the global city. The importance of Rodinsky’s Room, it argues, lies in the fact that it
Liebovich, Betty
2014-01-01
Rachel and Margaret McMillan created an open-air nursery in Deptford, London that has influenced early years education for 100 years. Their vision for young children living in poverty and deprivation to have access to fresh air through outdoor learning, nutritious meals, and an enriching environment to explore and develop has been embraced and…
Mohindra, R
2009-05-01
The difficulty in discovering a difference between killing and letting die has led many philosophers to deny the distinction. This paper seeks to develop an argument defending the distinction between killing and letting die. In relation to Rachels' cases, the argument is that (a) even accepting that Smith and Jones may select equally heinous options from the choices they have available to them, (b) the fact that the choices available to them are different is morally relevant, and (c) this difference in available choices can be used to distinguish between the agents in certain circumstances. It is the principle of justice, as espoused by Aristotle, which requires that equal things are treated equally and that unequal things are treated unequally that creates a presumption that Smith and Jones should be treated differently. The magnitude of this difference can be amplified by other premises, making the distinction morally relevant in practical reality.
Integrability of Liouville system on high genus Riemann surface: Pt. 1
International Nuclear Information System (INIS)
Chen Yixin; Gao Hongbo
1992-01-01
By using the theory of uniformization of Riemann-surfaces, we study properties of the Liouville equation and its general solution on a Riemann surface of genus g>1. After obtaining Hamiltonian formalism in terms of free fields and calculating classical exchange matrices, we prove the classical integrability of Liouville system on high genus Riemann surface
Growing up in Wartime England—A Selection from "The Rachel Chronicles: A Kind of Memoir"
Directory of Open Access Journals (Sweden)
Lilian R. Furst
2012-10-01
Full Text Available The following contribution is an excerpt from the unpublished memoirs of Austrian Jewish émigrée, Lilian Renée Furst (1931–2009, a pioneer in the field of comparative literature. This journal issue grew out of an April 2011 conference in her memory, held at the National Humanities Center, on “Jewish emigres and the Shaping of Postwar Culture.” The nexus between her innovative intellectual contributions and her experience as a Jewish émigré reflects one of the conference's central concerns: How, why, and in what fashion did the émigrés' dislocations shape innovative intellectual paths and cosmopolitan visions of Europe and European culture. Born in Austria and educated in England, Furst pursued an intellectual career in the United States, hoping it would allow her to break out of narrow national boundaries. The excerpt of her memoir here illuminates how her life's work as a pioneer in the field of comparative literary studies grew out of her experience with language as a German-speaking refugee in wartime England. Her memoir written in the third person about “Rachel” also reflects her dual identity as Jew and European. Part I by Dr. Anabel Aliaga-Buchenau, the literary executor of the memoir and a former graduate student of Furst, places “The Rachel Chronicles: A Kind of Memoir” in relation to Furst's other autobiographical writing. Part II includes Furst's own introduction to “The Rachel Chronicles,” followed by her chapter on “Growing up in wartime England.” (The whole of her unpublished memoir is available to researchers in the "Personal Papers of Lilian R. Furst," Girton College Archives, Cambridge University (http://janus.lib.cam.ac.uk/db/node.xsp?id=EAD%2FGBR%2F0271%2FGCPP%20Furst. Part III is a bibliography of Furst's writings.
On an isospectrality question over compact Riemann surfaces
International Nuclear Information System (INIS)
Srinivas Rau, S.
1990-01-01
It is proved that for a generic compact Riemann surface X of genus g>1,(i) there are at most 2 2g unitary characters of π 1 (X) whose associated line bundles have laplacians of identical spectrum, (ii) generating cycles for π 1 (X) can be chosen to be closed geodesics whose length multiplicity is 1. (author). 5 refs
Quantum Riemann surfaces. Pt. 2; The discrete series
Energy Technology Data Exchange (ETDEWEB)
Klimek, S. (Dept. of Mathematics, IUPUI, Indianapolis, IN (United States)); Lesniewski, A. (Dept. of Physics, Harvard Univ., Cambridge, MA (United States))
1992-02-01
We continue our study of noncommutative deformations of two-dimensional hyperbolic manifolds which we initiated in Part I. We construct a sequence of C{sup *}-algebras which are quantizations of a compact Riemann surface of genus g corresponding to special values of the Planck constant. These algebras are direct integrals of finite-dimensional C{sup *}-algebras. (orig.).
Colliding holes in Riemann surfaces and quantum cluster algebras
Chekhov, Leonid; Mazzocco, Marta
2018-01-01
In this paper, we describe a new type of surgery for non-compact Riemann surfaces that naturally appears when colliding two holes or two sides of the same hole in an orientable Riemann surface with boundary (and possibly orbifold points). As a result of this surgery, bordered cusps appear on the boundary components of the Riemann surface. In Poincaré uniformization, these bordered cusps correspond to ideal triangles in the fundamental domain. We introduce the notion of bordered cusped Teichmüller space and endow it with a Poisson structure, quantization of which is achieved with a canonical quantum ordering. We give a complete combinatorial description of the bordered cusped Teichmüller space by introducing the notion of maximal cusped lamination, a lamination consisting of geodesic arcs between bordered cusps and closed geodesics homotopic to the boundaries such that it triangulates the Riemann surface. We show that each bordered cusp carries a natural decoration, i.e. a choice of a horocycle, so that the lengths of the arcs in the maximal cusped lamination are defined as λ-lengths in Thurston-Penner terminology. We compute the Goldman bracket explicitly in terms of these λ-lengths and show that the groupoid of flip morphisms acts as a generalized cluster algebra mutation. From the physical point of view, our construction provides an explicit coordinatization of moduli spaces of open/closed string worldsheets and their quantization.
Weyl transforms associated with the Riemann-Liouville operator
Directory of Open Access Journals (Sweden)
N. B. Hamadi
2006-01-01
Full Text Available For the Riemann-Liouville transform ℛα, α∈ℝ+, associated with singular partial differential operators, we define and study the Weyl transforms Wσ connected with ℛα, where σ is a symbol in Sm, m∈ℝ. We give criteria in terms of σ for boundedness and compactness of the transform Wσ.
Weyl and Riemann-Liouville multifractional Ornstein-Uhlenbeck processes
International Nuclear Information System (INIS)
Lim, S C; Teo, L P
2007-01-01
This paper considers two new multifractional stochastic processes, namely the Weyl multifractional Ornstein-Uhlenbeck process and the Riemann-Liouville multifractional Ornstein-Uhlenbeck process. Basic properties of these processes such as locally self-similar property and Hausdorff dimension are studied. The relationship between the multifractional Ornstein-Uhlenbeck processes and the corresponding multifractional Brownian motions is established
Toeplitz operators on higher Cauchy-Riemann spaces
Czech Academy of Sciences Publication Activity Database
Engliš, Miroslav; Zhang, G.
2017-01-01
Roč. 22, č. 22 (2017), s. 1081-1116 ISSN 1431-0643 Institutional support: RVO:67985840 Keywords : Toeplitz operator * Hankel operator * Cauchy-Riemann operators Subject RIV: BA - General Math ematics OBOR OECD: Pure math ematics Impact factor: 0.800, year: 2016 https://www. math .uni-bielefeld.de/documenta/vol-22/32.html
The beauty of the Riemann-Silberstein vector
International Nuclear Information System (INIS)
Bialynicki-Birula, I.
2005-01-01
Beams of light carrying angular momentum have recently been widely studied theoretically and experimentally. In my talk I will show that the description of these beams in terms of the Riemann-Silberstein vector offers many advantages. In particular, it provides a natural bridge between the classical and the quantum description. (author)
Approximate Riemann solver for the two-fluid plasma model
International Nuclear Information System (INIS)
Shumlak, U.; Loverich, J.
2003-01-01
An algorithm is presented for the simulation of plasma dynamics using the two-fluid plasma model. The two-fluid plasma model is more general than the magnetohydrodynamic (MHD) model often used for plasma dynamic simulations. The two-fluid equations are derived in divergence form and an approximate Riemann solver is developed to compute the fluxes of the electron and ion fluids at the computational cell interfaces and an upwind characteristic-based solver to compute the electromagnetic fields. The source terms that couple the fluids and fields are treated implicitly to relax the stiffness. The algorithm is validated with the coplanar Riemann problem, Langmuir plasma oscillations, and the electromagnetic shock problem that has been simulated with the MHD plasma model. A numerical dispersion relation is also presented that demonstrates agreement with analytical plasma waves
Riemann-Theta Boltzmann Machine arXiv
Krefl, Daniel; Haghighat, Babak; Kahlen, Jens
A general Boltzmann machine with continuous visible and discrete integer valued hidden states is introduced. Under mild assumptions about the connection matrices, the probability density function of the visible units can be solved for analytically, yielding a novel parametric density function involving a ratio of Riemann-Theta functions. The conditional expectation of a hidden state for given visible states can also be calculated analytically, yielding a derivative of the logarithmic Riemann-Theta function. The conditional expectation can be used as activation function in a feedforward neural network, thereby increasing the modelling capacity of the network. Both the Boltzmann machine and the derived feedforward neural network can be successfully trained via standard gradient- and non-gradient-based optimization techniques.
Exploration and extension of an improved Riemann track fitting algorithm
Strandlie, A.; Frühwirth, R.
2017-09-01
Recently, a new Riemann track fit which operates on translated and scaled measurements has been proposed. This study shows that the new Riemann fit is virtually as precise as popular approaches such as the Kalman filter or an iterative non-linear track fitting procedure, and significantly more precise than other, non-iterative circular track fitting approaches over a large range of measurement uncertainties. The fit is then extended in two directions: first, the measurements are allowed to lie on plane sensors of arbitrary orientation; second, the full error propagation from the measurements to the estimated circle parameters is computed. The covariance matrix of the estimated track parameters can therefore be computed without recourse to asymptotic properties, and is consequently valid for any number of observation. It does, however, assume normally distributed measurement errors. The calculations are validated on a simulated track sample and show excellent agreement with the theoretical expectations.
Pseudo-periodic maps and degeneration of Riemann surfaces
Matsumoto, Yukio
2011-01-01
The first part of the book studies pseudo-periodic maps of a closed surface of genus greater than or equal to two. This class of homeomorphisms was originally introduced by J. Nielsen in 1944 as an extension of periodic maps. In this book, the conjugacy classes of the (chiral) pseudo-periodic mapping classes are completely classified, and Nielsen’s incomplete classification is corrected. The second part applies the results of the first part to the topology of degeneration of Riemann surfaces. It is shown that the set of topological types of all the singular fibers appearing in one-parameter holomorphic families of Riemann surfaces is in a bijective correspondence with the set of conjugacy classes of the pseudo-periodic maps of negative twists. The correspondence is given by the topological monodromy.
Extended Riemann-Liouville type fractional derivative operator with applications
Directory of Open Access Journals (Sweden)
Agarwal P.
2017-12-01
Full Text Available The main purpose of this paper is to introduce a class of new extended forms of the beta function, Gauss hypergeometric function and Appell-Lauricella hypergeometric functions by means of the modified Bessel function of the third kind. Some typical generating relations for these extended hypergeometric functions are obtained by defining the extension of the Riemann-Liouville fractional derivative operator. Their connections with elementary functions and Fox’s H-function are also presented.
Quantum field theory on higher-genus Riemann surfaces, 2
International Nuclear Information System (INIS)
Kubo, Reijiro; Ojima, Shuichi.
1990-08-01
Quantum field theory for closed bosonic string systems is formulated on arbitrary higher-genus Riemann surfaces in global operator formalism. Canonical commutation relations between bosonic string field X μ and their conjugate momenta P ν are derived in the framework of conventional quantum field theory. Problems arising in quantizing bosonic systems are considered in detail. Applying the method exploited in the preceding paper we calculate Ward-Takahashi identities. (author)
A contribution to the great Riemann solver debate
Quirk, James J.
1992-01-01
The aims of this paper are threefold: to increase the level of awareness within the shock capturing community to the fact that many Godunov-type methods contain subtle flaws that can cause spurious solutions to be computed; to identify one mechanism that might thwart attempts to produce very high resolution simulations; and to proffer a simple strategy for overcoming the specific failings of individual Riemann solvers.
Submaximal Riemann-Roch expected curves and symplectic packing.
Directory of Open Access Journals (Sweden)
Wioletta Syzdek
2007-06-01
Full Text Available We study Riemann-Roch expected curves on $mathbb{P}^1 imes mathbb{P}^1$ in the context of the Nagata-Biran conjecture. This conjecture predicts that for sufficiently large number of points multiple points Seshadri constants of an ample line bundle on algebraic surface are maximal. Biran gives an effective lower bound $N_0$. We construct examples verifying to the effect that the assertions of the Nagata-Biran conjecture can not hold for small number of points. We discuss cases where our construction fails. We observe also that there exists a strong relation between Riemann-Roch expected curves on $mathbb{P}^1 imes mathbb{P}^1$ and the symplectic packing problem. Biran relates the packing problem to the existence of solutions of certain Diophantine equations. We construct such solutions for any ample line bundle on $mathbb{P}^1 imes mathbb{P}^1$ and a relatively smallnumber of points. The solutions geometrically correspond to Riemann-Roch expected curves. Finally we discuss in how far the Biran number $N_0$ is optimal in the case of mathbb{P}^1 imes mathbb{P}^1. In fact we conjecture that it can be replaced by a lower number and we provide evidence justifying this conjecture.
Conformal scalar fields and chiral splitting on super Riemann surfaces
International Nuclear Information System (INIS)
D'Hoker, E.; Phong, D.H.
1989-01-01
We provide a complete description of correlation functions of scalar superfields on a super Riemann surface, taking into account zero modes and non-trivial topology. They are built out of chirally split correlation functions, or conformal blocks at fixed internal momenta. We formulate effective rules which determine these completely in terms of geometric invariants of the super Riemann surface. The chirally split correlation functions have non-trivial monodromy and produce single-valued amplitudes only upon integration over loop momenta. Our discussion covers the even spin structure as well as the odd spin structure case which had been the source of many difficulties in the past. Super analogues of Green's functions, holomorphic spinors, and prime forms emerge which should pave the way to function theory on super Riemann surfaces. In superstring theories, chirally split amplitudes for scalar superfields are crucial in enforcing the GSO projection required for consistency. However one really knew how to carry this out only in the operator formalism to one-loop order. Our results provide a way of enforcing the GSO projection to any loop. (orig.)
Method of construction of the Riemann function for a second-order hyperbolic equation
Aksenov, A. V.
2017-12-01
A linear hyperbolic equation of the second order in two independent variables is considered. The Riemann function of the adjoint equation is shown to be invariant with respect to the fundamental solutions transformation group. Symmetries and symmetries of fundamental solutions of the Euler-Poisson-Darboux equation are found. The Riemann function is constructed with the aid of fundamental solutions symmetries. Examples of the application of the algorithm for constructing Riemann function are given.
Derivative-Based Trapezoid Rule for the Riemann-Stieltjes Integral
Directory of Open Access Journals (Sweden)
Weijing Zhao
2014-01-01
Full Text Available The derivative-based trapezoid rule for the Riemann-Stieltjes integral is presented which uses 2 derivative values at the endpoints. This kind of quadrature rule obtains an increase of two orders of precision over the trapezoid rule for the Riemann-Stieltjes integral and the error term is investigated. At last, the rationality of the generalization of derivative-based trapezoid rule for Riemann-Stieltjes integral is demonstrated.
On the $a$-points of the derivatives of the Riemann zeta function
Onozuka, Tomokazu
2016-01-01
We prove three results on the $a$-points of the derivatives of the Riemann zeta function. The first result is a formula of the Riemann-von Mangoldt type; we estimate the number of the $a$-points of the derivatives of the Riemann zeta function. The second result is on certain exponential sum involving $a$-points. The third result is an analogue of the zero density theorem. We count the $a$-points of the derivatives of the Riemann zeta function in $1/2-(\\log\\log T)^2/\\log T
Wonders with the Sea: Rachel Carson’s Ecological Aesthetic and the Mid-Century Reader
Directory of Open Access Journals (Sweden)
Amanda Hagood
2013-05-01
Full Text Available Recent scholarship on the work of the great nature writer, Rachel Carson, posits that her landmark book, Silent Spring (1962—often credited with igniting the modern environmental movement—is best understood in the context of her earlier, extraordinarily popular publications on the natural history of the oceans, which helped establish her as a talented and trustworthy translator of scientific concepts into literary prose. This essay builds upon that idea, showing how Carson’s The Sea Around Us (1951 and The Edge of the Sea (1955 not only shaped public understandings of ocean ecology, but also spurred a public passion for all things oceanographic, best embodied in a wave of “Carsonalia”—consumer items and experiences ranging from hats, to Book of the Month Club editions, to liner notes for the NBC Symphony’s recording of Debussy’s La Mer. While these items inspired and expressed the “sense of wonder” that was critical to Carson’s ecological aesthetic, I argue, they also subsumed the new “frontier” of the world’s oceans into the technological imperialism of the post-World War II United States. As new technologies allowed military and scientific researchers to see deeper into the oceanic depths than ever before, images of the open ocean were domesticated through consumer markets into viewable, readable, and even wearable forms. This commodification of the ocean, and of Carson’s ecocentric message, both enabled and frustrated her attempts to promote ecological literacy. Yet they also reveal much about our contemporary relationship to the world’s oceans, which remain sites of both enduring wonder and extraordinary exploitation.
Integrable systems twistors, loop groups, and Riemann surfaces
Hitchin, NJ; Ward, RS
2013-01-01
This textbook is designed to give graduate students an understanding of integrable systems via the study of Riemann surfaces, loop groups, and twistors. The book has its origins in a series of lecture courses given by the authors, all of whom are internationally known mathematicians and renowned expositors. It is written in an accessible and informal style, and fills a gap in the existing literature. The introduction by Nigel Hitchin addresses the meaning of integrability: how do werecognize an integrable system? His own contribution then develops connections with algebraic geometry, and inclu
Bosonization in a two-dimensional Riemann Cartan geometry
International Nuclear Information System (INIS)
Denardo, G.; Spallucci, E.
1987-01-01
We study the vacuum functional for a Dirac field in a two dimensional Riemann-Cartan geometry. Torsion is treated as a quantum variable while the metric is considered as a classical background field. Decoupling spinors from the non-Riemannian part of the geometry introduces a chiral Jacobian into the vacuum generating functional. We compute this functional Jacobian determinant by means of the Alvarez method. Finally, we show that the effective action for the background geometry is of the Liouville type and does not preserve any memory of the initial torsion field. (author)
The Riemann zeta-function theory and applications
Ivic, Aleksandar
2003-01-01
""A thorough and easily accessible account.""-MathSciNet, Mathematical Reviews on the Web, American Mathematical Society. This extensive survey presents a comprehensive and coherent account of Riemann zeta-function theory and applications. Starting with elementary theory, it examines exponential integrals and exponential sums, the Voronoi summation formula, the approximate functional equation, the fourth power moment, the zero-free region, mean value estimates over short intervals, higher power moments, and omega results. Additional topics include zeros on the critical line, zero-density estim
Riemann-Roch Spaces and Linear Network Codes
DEFF Research Database (Denmark)
Hansen, Johan P.
We construct linear network codes utilizing algebraic curves over finite fields and certain associated Riemann-Roch spaces and present methods to obtain their parameters. In particular we treat the Hermitian curve and the curves associated with the Suzuki and Ree groups all having the maximal...... number of points for curves of their respective genera. Linear network coding transmits information in terms of a basis of a vector space and the information is received as a basis of a possibly altered vector space. Ralf Koetter and Frank R. Kschischang %\\cite{DBLP:journals/tit/KoetterK08} introduced...... in the above metric making them suitable for linear network coding....
Extended KN algebras and extended conformal field theories over higher genus Riemann surfaces
International Nuclear Information System (INIS)
Ceresole, A.; Huang Chaoshang
1990-01-01
A global operator formalism for extended conformal field theories over higher genus Riemann surfaces is introduced and extended KN algebra are obtained by means of the KN bases. The BBSS construction of the spin-3 operator is carried out for Kac-Moody algebra A 2 over a Riemann surface of arbitrary genus. (orig.)
Superconformal structures and holomorphic 1/2-superdifferentials on N=1 super Riemann surfaces
International Nuclear Information System (INIS)
Kachkachi, H.; Kachkachi, M.
1992-07-01
Using the Super Riemann-Roch theorem we give a local expression for a holomorphic 1/2-superdifferential in a superconformal structure parametrized by special isothermal coordinates on an N=1 Super Riemann Surface (SRS). This construction is done by choosing a suitable origin for these coordinates. The holomorphy of the latter with respect to super Beltrami differentials is proven. (author). 26 refs
Superconformal algebra on meromorphic vector fields with three poles on super-Riemann sphere
International Nuclear Information System (INIS)
Wang Shikun; Xu Kaiwen.
1989-07-01
Based upon the Riemann-Roch theorem, we construct superconformal algebra of meromorphic vector fields with three poles and the relevant abelian differential of the third kind on super Riemann sphere. The algebra includes two Ramond sectors as subalgebra, and implies a picture of interaction of three superstrings. (author). 14 refs
Two-Loop Scattering Amplitudes from the Riemann Sphere
Geyer, Yvonne; Monteiro, Ricardo; Tourkine, Piotr
2016-01-01
The scattering equations give striking formulae for massless scattering amplitudes at tree level and, as shown recently, at one loop. The progress at loop level was based on ambitwistor string theory, which naturally yields the scattering equations. We proposed that, for ambitwistor strings, the standard loop expansion in terms of the genus of the worldsheet is equivalent to an expansion in terms of nodes of a Riemann sphere, with the nodes carrying the loop momenta. In this paper, we show how to obtain two-loop scattering equations with the correct factorization properties. We adapt genus-two integrands from the ambitwistor string to the nodal Riemann sphere and show that these yield correct answers, by matching standard results for the four-point two-loop amplitudes of maximal supergravity and super-Yang-Mills theory. In the Yang-Mills case, this requires the loop analogue of the Parke-Taylor factor carrying the colour dependence, which includes non-planar contributions.
Poisson sigma model with branes and hyperelliptic Riemann surfaces
International Nuclear Information System (INIS)
Ferrario, Andrea
2008-01-01
We derive the explicit form of the superpropagators in the presence of general boundary conditions (coisotropic branes) for the Poisson sigma model. This generalizes the results presented by Cattaneo and Felder [''A path integral approach to the Kontsevich quantization formula,'' Commun. Math. Phys. 212, 591 (2000)] and Cattaneo and Felder ['Coisotropic submanifolds in Poisson geometry and branes in the Poisson sigma model', Lett. Math. Phys. 69, 157 (2004)] for Kontsevich's angle function [Kontsevich, M., 'Deformation quantization of Poisson manifolds I', e-print arXiv:hep.th/0101170] used in the deformation quantization program of Poisson manifolds. The relevant superpropagators for n branes are defined as gauge fixed homotopy operators of a complex of differential forms on n sided polygons P n with particular ''alternating'' boundary conditions. In the presence of more than three branes we use first order Riemann theta functions with odd singular characteristics on the Jacobian variety of a hyperelliptic Riemann surface (canonical setting). In genus g the superpropagators present g zero mode contributions
Fractal supersymmetric QM, Geometric Probability and the Riemann Hypothesis
Castro, C
2004-01-01
The Riemann's hypothesis (RH) states that the nontrivial zeros of the Riemann zeta-function are of the form $ s_n =1/2+i\\lambda_n $. Earlier work on the RH based on supersymmetric QM, whose potential was related to the Gauss-Jacobi theta series, allows to provide the proper framework to construct the well defined algorithm to compute the probability to find a zero (an infinity of zeros) in the critical line. Geometric probability theory furnishes the answer to the very difficult question whether the probability that the RH is true is indeed equal to unity or not. To test the validity of this geometric probabilistic framework to compute the probability if the RH is true, we apply it directly to the the hyperbolic sine function $ \\sinh (s) $ case which obeys a trivial analog of the RH (the HSRH). Its zeros are equally spaced in the imaginary axis $ s_n = 0 + i n \\pi $. The geometric probability to find a zero (and an infinity of zeros) in the imaginary axis is exactly unity. We proceed with a fractal supersymme...
Large chiral diffeomorphisms on Riemann surfaces and W-algebras
International Nuclear Information System (INIS)
Bandelloni, G.; Lazzarini, S.
2006-01-01
The diffeomorphism action lifted on truncated (chiral) Taylor expansion of a complex scalar field over a Riemann surface is presented in the paper under the name of large diffeomorphisms. After an heuristic approach, we show how a linear truncation in the Taylor expansion can generate an algebra of symmetry characterized by some structure functions. Such a linear truncation is explicitly realized by introducing the notion of Forsyth frame over the Riemann surface with the help of a conformally covariant algebraic differential equation. The large chiral diffeomorphism action is then implemented through a Becchi-Rouet-Stora (BRS) formulation (for a given order of truncation) leading to a more algebraic setup. In this context the ghost fields behave as holomorphically covariant jets. Subsequently, the link with the so-called W-algebras is made explicit once the ghost parameters are turned from jets into tensorial ghost ones. We give a general solution with the help of the structure functions pertaining to all the possible truncations lower or equal to the given order. This provides another contribution to the relationship between Korteweg-de Vries (KdV) flows and W-diffeomorphims
Inverse Scattering, the Coupling Constant Spectrum, and the Riemann Hypothesis
International Nuclear Information System (INIS)
Khuri, N. N.
2002-01-01
It is well known that the s-wave Jost function for a potential, λV, is an entire function of λ with an infinite number of zeros extending to infinity. For a repulsive V, and at zero energy, these zeros of the 'coupling constant', λ, will all be real and negative, λ n (0) n n =1/2+iγ n . Thus, finding a repulsive V whose coupling constant spectrum coincides with the Riemann zeros will establish the Riemann hypothesis, but this will be a very difficult and unguided search.In this paper we make a significant enlargement of the class of potentials needed for a generalization of the above idea. We also make this new class amenable to construction via inverse scattering methods. We show that all one needs is a one parameter class of potentials, U(s;x), which are analytic in the strip, 0≤Res≤1, Ims>T 0 , and in addition have an asymptotic expansion in powers of [s(s-1)] -1 , i.e. U(s;x)=V 0 (x)+gV 1 (x)+g 2 V 2 (x)+...+O(g N ), with g=[s(s-1)] -1 . The potentials V n (x) are real and summable. Under suitable conditions on the V n 's and the O(g N ) term we show that the condition, ∫ 0 ∞ vertical bar f 0 (x) vertical bar 2 V 1 (x) dx≠0, where f 0 is the zero energy and g=0 Jost function for U, is sufficient to guarantee that the zeros g n are real and, hence, s n =1/2+iγ n , for γ n ≥T 0 .Starting with a judiciously chosen Jost function, M(s,k), which is constructed such that M(s,0) is Riemann's ξ(s) function, we have used inverse scattering methods to actually construct a U(s;x) with the above properties. By necessity, we had to generalize inverse methods to deal with complex potentials and a nonunitary S-matrix. This we have done at least for the special cases under consideration.For our specific example, ∫ 0 ∞ vertical bar f 0 (x) vertical bar 2 V 1 (x) dx=0 and, hence, we get no restriction on Img n or Res n . The reasons for the vanishing of the above integral are given, and they give us hints on what one needs to proceed further. The problem
Sullivan, Grace
2017-01-01
In 2012, Trayvon Martin was killed by George Zimmerman, who, after a month-long highly-publicized trial, was acquitted of second-degree murder. In this study, I examine the testimony of Martin's childhood friend and key witness for the prosecution, Rachel Jeantel. Although Rachel Jeantel was an ear witness to the altercation between Zimmerman and…
Polynomials, Riemann surfaces, and reconstructing missing-energy events
Gripaios, Ben; Webber, Bryan
2011-01-01
We consider the problem of reconstructing energies, momenta, and masses in collider events with missing energy, along with the complications introduced by combinatorial ambiguities and measurement errors. Typically, one reconstructs more than one value and we show how the wrong values may be correlated with the right ones. The problem has a natural formulation in terms of the theory of Riemann surfaces. We discuss examples including top quark decays in the Standard Model (relevant for top quark mass measurements and tests of spin correlation), cascade decays in models of new physics containing dark matter candidates, decays of third-generation leptoquarks in composite models of electroweak symmetry breaking, and Higgs boson decay into two tau leptons.
Supersymmetric Dirac particles in Riemann-Cartan space-time
International Nuclear Information System (INIS)
Rumpf, H.
1981-01-01
A natural extension of the supersymmetric model of Di Vecchia and Ravndal yields a nontrivial coupling of classical spinning particles to torsion in a Riemann-Cartan geometry. The equations of motion implied by this model coincide with a consistent classical limit of the Heisenberg equations derived from the minimally coupled Dirac equation. Conversely, the latter equation is shown to arise from canonical quantization of the classical system. The Heisenberg equations are obtained exact in all powers of h/2π and thus complete the partial results of previous WKB calculations. The author also considers such matters of principle as the mathematical realization of anticommuting variables, the physical interpretation of supersymmetry transformations, and the effective variability of rest mass. (Auth.)
A New Riemann Type Hydrodynamical Hierarchy and its Integrability Analysis
International Nuclear Information System (INIS)
Golenia, Jolanta Jolanta; Bogolubov, Nikolai N. Jr.; Popowicz, Ziemowit; Pavlov, Maxim V.; Prykarpatsky, Anatoliy K.
2009-12-01
Short-wave perturbations in a relaxing medium, governed by a special reduction of the Ostrovsky evolution equation, and later derived by Whitham, are studied using the gradient-holonomic integrability algorithm. The bi-Hamiltonicity and complete integrability of the corresponding dynamical system is stated and an infinite hierarchy of commuting to each other conservation laws of dispersive type are found. The well defined regularization of the model is constructed and its Lax type integrability is discussed. A generalized hydrodynamical Riemann type system is considered, infinite hierarchies of conservation laws, related compatible co-symplectic structures and Lax type representations for the special cases N = 2, 3 and N = 4 are constructed. (author)
The Picard group of the moduli space of r-Spin Riemann surfaces
DEFF Research Database (Denmark)
Randal-Williams, Oscar
2012-01-01
An r-Spin Riemann surface is a Riemann surface equipped with a choice of rth root of the (co)tangent bundle. We give a careful construction of the moduli space (orbifold) of r-Spin Riemann surfaces, and explain how to establish a Madsen–Weiss theorem for it. This allows us to prove the “Mumford...... conjecture” for these moduli spaces, but more interestingly allows us to compute their algebraic Picard groups (for g≥10, or g≥9 in the 2-Spin case). We give a complete description of these Picard groups, in terms of explicitly constructed line bundles....
Directory of Open Access Journals (Sweden)
Xuefeng Wei
2016-12-01
Full Text Available This article concerns the wave interaction problem for a strictly hyperbolic system of conservation laws whose Riemann solutions involve delta shock waves. To cover all situations, the global solutions are constructed when the initial data are taken as three piecewise constant states. It is shown that the Riemann solutions are stable with respect to a specific small perturbation of the Riemann initial data. In addition, some interesting nonlinear phenomena are captured during the process of constructing the solutions, such as the generation and decomposition of delta shock waves.
Buckley, Elizabeth M.
2009-01-01
This project explores two sacred cantatas of Elisabeth-Claude Jacquet de La Guerre, "Esther" and "Jacob, et Rachel". The cultural milieu in which the sacred cantatas of Jacquet de La Guerre were written and performed will be discussed, as well as possible venues for their original performances, including the Parisian salon, and…
Physical and Geometric Interpretations of the Riemann Tensor, Ricci Tensor, and Scalar Curvature
Loveridge, Lee C.
2004-01-01
Various interpretations of the Riemann Curvature Tensor, Ricci Tensor, and Scalar Curvature are described. Also, the physical meanings of the Einstein Tensor and Einstein's Equations are discussed. Finally a derivation of Newtonian Gravity from Einstein's Equations is given.
Directory of Open Access Journals (Sweden)
Johnny Henderson
2016-01-01
Full Text Available We investigate the existence and nonexistence of positive solutions for a system of nonlinear Riemann-Liouville fractional differential equations with two parameters, subject to coupled integral boundary conditions.
Prime Obsession: Bernhard Riemann and the Greatest Unsolved Problem in Mathematics
National Research Council Canada - National Science Library
Derbyshire, John
2003-01-01
.... Is the hypothesis true or false?Riemann's basic inquiry, the primary topic of his paper, concerned a straightforward but nevertheless important matter of arithmetic defining a precise formula to track and identify the occurrence...
Nontrivial Solution of Fractional Differential System Involving Riemann-Stieltjes Integral Condition
Directory of Open Access Journals (Sweden)
Ge-Feng Yang
2012-01-01
differential system involving the Riemann-Stieltjes integral condition, by using the Leray-Schauder nonlinear alternative and the Banach contraction mapping principle, some sufficient conditions of the existence and uniqueness of a nontrivial solution of a system are obtained.
A variational approach to closed bosonic strings on bordered Riemann surfaces
International Nuclear Information System (INIS)
Ohrndorf, T.
1987-01-01
Polyakov's path integral for bosonic closed strings defined on a bordered Riemann surface is investigated by variational methods. It is demonstrated that boundary variations are generated by the Virasoro operators. The investigation is performed for both, simply connected Riemann surfaces as well as ringlike domains. It is shown that the form of the variational operator is the same on both kinds of surfaces. The Virasoro algebra arises as a consistency condition for the variation. (orig.)
Probability laws related to the Jacobi theta and Riemann zeta function and Brownian excursions
Biane, P.; Pitman, J.; Yor, M.
1999-01-01
This paper reviews known results which connect Riemann's integral representations of his zeta function, involving Jacobi's theta function and its derivatives, to some particular probability laws governing sums of independent exponential variables. These laws are related to one-dimensional Brownian motion and to higher dimensional Bessel processes. We present some characterizations of these probability laws, and some approximations of Riemann's zeta function which are related to these laws.
Essay on Fractional Riemann-Liouville Integral Operator versus Mikusinski’s
Directory of Open Access Journals (Sweden)
Ming Li
2013-01-01
Full Text Available This paper presents the representation of the fractional Riemann-Liouville integral by using the Mikusinski operators. The Mikusinski operators discussed in the paper may yet provide a new view to describe and study the fractional Riemann-Liouville integral operator. The present result may be useful for applying the Mikusinski operational calculus to the study of fractional calculus in mathematics and to the theory of filters of fractional order in engineering.
The Euler–Riemann gases, and partition identities
International Nuclear Information System (INIS)
Chair, Noureddine
2013-01-01
The Euler theorem in partition theory and its generalization are derived from a non-interacting quantum field theory in which each bosonic mode with a given frequency is equivalent to a sum of bosonic mode whose frequency is twice (s-times) as much, and a fermionic (parafermionic) mode with the same frequency. Explicit formulas for the graded parafermionic partition functions are obtained, and the inverse of the graded partition function (IGPPF), turns out to be bosonic (fermionic) partition function depending on the parity of the order s of the parafermions. It is also shown that these partition functions are generating functions of partitions of integers with restrictions, the Euler generating function is identified with the inverse of the graded parafermionic partition function of order 2. As a result we obtain new sequences of partitions of integers with given restrictions. If the parity of the order s is even, then mixing a system of parafermions with a system whose partition function is (IGPPF), results in a system of fermions and bosons. On the other hand, if the parity of s is odd, then, the system we obtain is still a mixture of fermions and bosons but the corresponding Fock space of states is truncated. It turns out that these partition functions are given in terms of the Jacobi theta function θ 4 , and generate sequences in partition theory. Our partition functions coincide with the overpartitions of Corteel and Lovejoy, and jagged partitions in conformal field theory. Also, the partition functions obtained are related to the Ramond characters of the superconformal minimal models, and in the counting of the Moore–Read edge spectra that appear in the fractional quantum Hall effect. The different partition functions for the Riemann gas that are the counter parts of the Euler gas are obtained by a simple change of variables. In particular the counter part of the Jacobi theta function is (ζ(2t))/(ζ(t) 2 ) . Finally, we propose two formulas which brings
Riemann's and Helmholtz-Lie's problems of space from Weyl's relativistic perspective
Bernard, Julien
2018-02-01
I reconstruct Riemann's and Helmholtz-Lie's problems of space, from some perspectives that allow for a fruitful comparison with Weyl. In Part II. of his inaugural lecture, Riemann justifies that the infinitesimal metric is the square root of a quadratic form. Thanks to Finsler geometry, I clarify both the implicit and explicit hypotheses used for this justification. I explain that Riemann-Finsler's kind of method is also appropriate to deal with indefinite metrics. Nevertheless, Weyl shares with Helmholtz a strong commitment to the idea that the notion of group should be at the center of the foundations of geometry. Riemann missed this point, and that is why, according to Weyl, he dealt with the problem of space in a "too formal" way. As a consequence, to solve the problem of space, Weyl abandoned Riemann-Finsler's methods for group-theoretical ones. However, from a philosophical point of view, I show that Weyl and Helmholtz are in strong opposition. The meditation on Riemann's inaugural lecture, and its clear methodological separation between the infinitesimal and the finite parts of the problem of space, must have been crucial for Weyl, while searching for strong epistemological foundations for the group-theoretical methods, avoiding Helmholtz's unjustified transition from the finite to the infinitesimal.
Ernst Equation and Riemann Surfaces: Analytical and Numerical Methods
International Nuclear Information System (INIS)
Ernst, Frederick J
2007-01-01
metric tensor components. The first two chapters of this book are devoted to some basic ideas: in the introductory chapter 1 the authors discuss the concept of integrability, comparing the integrability of the vacuum Ernst equation with the integrability of nonlinear equations of Korteweg-de Vries (KdV) type, while in chapter 2 they describe various circumstances in which the vacuum Ernst equation has been determined to be relevant, not only in connection with gravitation but also, for example, in the construction of solutions of the self-dual Yang-Mills equations. It is also in this chapter that one of several equivalent linear systems for the Ernst equation is described. The next two chapters are devoted to Dmitry Korotkin's concept of algebro-geometric solutions of a linear system: in chapter 3 the structure of such solutions of the vacuum Ernst equation, which involve Riemann theta functions of hyperelliptic algebraic curves of any genus, is contrasted with the periodic structure of such solutions of the KdV equation. How such solutions can be obtained, for example, by solving a matrix Riemann-Hilbert problem and how the metric tensor of the associated spacetime can be evaluated is described in detail. In chapter 4 the asymptotic behaviour and the similarity structure of the general algebro-geometric solutions of the Ernst equation are described, and the relationship of such solutions to the perhaps more familiar multi-soliton solutions is discussed. The next three chapters are based upon the authors' own published research: in chapter 5 it is shown that a problem involving counter-rotating infinitely thin disks of matter can be solved in terms of genus two Riemann theta functions, while in chapter 6 the authors describe numerical methods that facilitate the construction of such solutions, and in chapter 7 three-dimensional graphs are displayed that depict all metrical fields of the associated spacetime. Finally, in chapter 8, the difficulties associated with
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Anton, Luis; MartI, Jose M; Ibanez, Jose M; Aloy, Miguel A.; Mimica, Petar; Miralles, Juan A.
2010-01-01
We obtain renormalized sets of right and left eigenvectors of the flux vector Jacobians of the relativistic MHD equations, which are regular and span a complete basis in any physical state including degenerate ones. The renormalization procedure relies on the characterization of the degeneracy types in terms of the normal and tangential components of the magnetic field to the wave front in the fluid rest frame. Proper expressions of the renormalized eigenvectors in conserved variables are obtained through the corresponding matrix transformations. Our work completes previous analysis that present different sets of right eigenvectors for non-degenerate and degenerate states, and can be seen as a relativistic generalization of earlier work performed in classical MHD. Based on the full wave decomposition (FWD) provided by the renormalized set of eigenvectors in conserved variables, we have also developed a linearized (Roe-type) Riemann solver. Extensive testing against one- and two-dimensional standard numerical problems allows us to conclude that our solver is very robust. When compared with a family of simpler solvers that avoid the knowledge of the full characteristic structure of the equations in the computation of the numerical fluxes, our solver turns out to be less diffusive than HLL and HLLC, and comparable in accuracy to the HLLD solver. The amount of operations needed by the FWD solver makes it less efficient computationally than those of the HLL family in one-dimensional problems. However, its relative efficiency increases in multidimensional simulations.
Minimal models on Riemann surfaces: The partition functions
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Foda, O.
1990-01-01
The Coulomb gas representation of the A n series of c=1-6/[m(m+1)], m≥3, minimal models is extended to compact Riemann surfaces of genus g>1. An integral representation of the partition functions, for any m and g is obtained as the difference of two gaussian correlation functions of a background charge, (background charge on sphere) x (1-g), and screening charges integrated over the surface. The coupling constant x (compacitification radius) 2 of the gaussian expressions are, as on the torus, m(m+1), and m/(m+1). The partition functions obtained are modular invariant, have the correct conformal anomaly and - restricting the propagation of states to a single handle - one can verify explicitly the decoupling of the null states. On the other hand, they are given in terms of coupled surface integrals, and it remains to show how they degenerate consistently to those on lower-genus surfaces. In this work, this is clear only at the lattice level, where no screening charges appear. (orig.)
Minimal models on Riemann surfaces: The partition functions
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Foda, O. (Katholieke Univ. Nijmegen (Netherlands). Inst. voor Theoretische Fysica)
1990-06-04
The Coulomb gas representation of the A{sub n} series of c=1-6/(m(m+1)), m{ge}3, minimal models is extended to compact Riemann surfaces of genus g>1. An integral representation of the partition functions, for any m and g is obtained as the difference of two gaussian correlation functions of a background charge, (background charge on sphere) x (1-g), and screening charges integrated over the surface. The coupling constant x (compacitification radius){sup 2} of the gaussian expressions are, as on the torus, m(m+1), and m/(m+1). The partition functions obtained are modular invariant, have the correct conformal anomaly and - restricting the propagation of states to a single handle - one can verify explicitly the decoupling of the null states. On the other hand, they are given in terms of coupled surface integrals, and it remains to show how they degenerate consistently to those on lower-genus surfaces. In this work, this is clear only at the lattice level, where no screening charges appear. (orig.).
Conformal fields. From Riemann surfaces to integrable hierarchies
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Semikhatov, A.M.
1991-01-01
I discuss the idea of translating ingredients of conformal field theory into the language of hierarchies of integrable differential equations. Primary conformal fields are mapped into (differential or matrix) operators living on the phase space of the hierarchy, whereas operator insertions of, e.g., a current or the energy-momentum tensor, become certain vector fields on the phase space and thus acquire a meaning independent of a given Riemann surface. A number of similarities are observed between the structures arising on the hierarchy and those of the theory on the world-sheet. In particular, there is an analogue of the operator product algebra with the Cauchy kernel replaced by its 'off-shell' hierarchy version. Also, hierarchy analogues of certain operator insertions admit two (equivalent, but distinct) forms, resembling the 'bosonized' and 'fermionized' versions respectively. As an application, I obtain a useful reformulation of the Virasoro constraints of the type that arise in matrix models, as a system of equations on dressing (or Lax) operators (rather than correlation functions, i.e., residues or traces). This also suggests an interpretation in terms of a 2D topological field theory, which might be extended to a correspondence between Virasoro-constrained hierarchies and topological theories. (orig.)
Numerical implication of Riemann problem theory for fluid dynamics
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Menikoff, R.
1988-01-01
The Riemann problem plays an important role in understanding the wave structure of fluid flow. It is also crucial step in some numerical algorithms for accurately and efficiently computing fluid flow; Godunov method, random choice method, and from tracking method. The standard wave structure consists of shock and rarefaction waves. Due to physical effects such as phase transitions, which often are indistinguishable from numerical errors in an equation of state, anomalkous waves may occur, ''rarefaction shocks'', split waves, and composites. The anomalous waves may appear in numerical calculations as waves smeared out by either too much artificial viscosity or insufficient resolution. In addition, the equation of state may lead to instabilities of fluid flow. Since these anomalous effects due to the equation of state occur for the continuum equations, they can be expected to occur for all computational algorithms. The equation of state may be characterized by three dimensionless variables: the adiabatic exponent γ, the Grueneisen coefficient Γ, and the fundamental derivative G. The fluid flow anomalies occur when inequalities relating these variables are violated. 18 refs
Orbifold Riemann surfaces: Teichmueller spaces and algebras of geodesic functions
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Mazzocco, Marta [Loughborough University, Loughborough (United Kingdom); Chekhov, Leonid O [Institute for Theoretical and Experimental Physics (Russian Federation State Scientific Center), Moscow (Russian Federation)
2009-12-31
A fat graph description is given for Teichmueller spaces of Riemann surfaces with holes and with Z{sub 2}- and Z{sub 3}-orbifold points (conical singularities) in the Poincare uniformization. The corresponding mapping class group transformations are presented, geodesic functions are constructed, and the Poisson structure is introduced. The resulting Poisson algebras are then quantized. In the particular cases of surfaces with n Z{sub 2}-orbifold points and with one and two holes, the respective algebras A{sub n} and D{sub n} of geodesic functions (classical and quantum) are obtained. The infinite-dimensional Poisson algebra D{sub n}, which is the semiclassical limit of the twisted q-Yangian algebra Y'{sub q}(o{sub n}) for the orthogonal Lie algebra o{sub n}, is associated with the algebra of geodesic functions on an annulus with n Z{sub 2}-orbifold points, and the braid group action on this algebra is found. From this result the braid group actions are constructed on the finite-dimensional reductions of this algebra: the p-level reduction and the algebra D{sub n}. The central elements for these reductions are found. Also, the algebra D{sub n} is interpreted as the Poisson algebra of monodromy data of a Frobenius manifold in the vicinity of a non-semisimple point. Bibliography: 36 titles.
Deduction of Einstein equation from homogeneity of Riemann spacetime
Ni, Jun
2012-03-01
The symmetry of spacetime translation leads to the energy-momentum conservation. However, the Lagrange depends on spacetime coordinates, which makes the symmetry of spacetime translation different with other symmetry invariant explicitly under symmetry transformation. We need an equation to guarantee the symmetry of spacetime translation. In this talk, I will show that the Einstein equation can be deduced purely from the general covariant principle and the homogeneity of spacetime in the frame of quantum field theory. The Einstein equation is shown to be the equation to guarantee the symmetry of spacetime translation. Gravity is an apparent force due to the curvature of spacetime resulted from the conservation of energy-momentum. In the action of quantum field, only electroweak-strong interactions appear with curved spacetime metric determined by the Einstein equation.. The general covariant principle and the homogeneity of spacetime are merged into one basic principle: Any Riemann spacetime metric guaranteeing the energy-momentum conservation are equivalent, which can be called as the conserved general covariant principle. [4pt] [1] Jun Ni, Chin. Phys. Lett. 28, 110401 (2011).
Montgomery, Ellyn T.; Ganju, Neil K.; Dickhudt, Patrick J.; Borden, Jonathan; Martini, Marinna A.; Brosnahan, Sandra M.
2015-01-01
Suspended-sediment transport is a critical element controlling the geomorphology of tidal wetland complexes. Wetlands rely on organic material and inorganic sediment deposition to maintain their elevation relative to sea level. The U.S. Geological Survey performed observational deployments to measure suspended-sediment concentration and water flow rates in the tidal channels of the wetlands in the Rachel Carson National Wildlife Refuge in Wells, Maine. The objective was to characterize the sediment-transport mechanisms that contribute to the net sediment budget of the wetland complex. We deployed a meteorological tower, optical turbidity sensors, and acoustic velocity meters at sites on Stephens Brook and the Ogunquit River between March 27 and December 9, 2013. This report presents the time-series oceanographic and atmospheric data collected during those field studies. The oceanographic parameters include water velocity, depth, turbidity, salinity, temperature, and pH. The atmospheric parameters include wind direction, speed, and gust; air temperature; air pressure; relative humidity; short wave radiation; and photosynthetically active radiation.
The continuous determination of spacetime geometry by the Riemann curvature tensor
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Rendall, A.D.
1988-01-01
It is shown that generically the Riemann tensor of a Lorentz metric on an n-dimensional manifold (n ≥ 4) determines the metric up to a constant factor and hence determines the associated torsion-free connection uniquely. The resulting map from Riemann tensors to connections is continuous in the Whitney Csup(∞) topology but, at least for some manifolds, constant factors cannot be chosen so as to make the map from Riemann tensors to metrics continuous in that topology. The latter map is, however, continuous in the compact open Csup(∞) topology so that estimates of the metric and its derivatives on a compact set can be obtained from similar estimates on the curvature and its derivatives. (author)
Quantized Dirac field in curved Riemann--Cartan background. I. Symmetry properties, Green's function
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Nieh, H.T.; Yan, M.L.
1982-01-01
In the present series of papers, we study the properties of quantized Dirac field in curved Riemann--Cartan space, with particular attention on the role played by torsion. In this paper, we give, in the spirit of the original work of Weyl, a systematic presentation of Dirac's theory in curved Riemann--Cartan space. We discuss symmetry properties of the system, and derive conservation laws as direct consequences of these symmetries. Also discussed is conformal gauge symmetry, with torsion effectively playing the role of a conformal gauge field. To obtain short-distance behavior, we calculate the spinor Green's function, in curved Riemann--Cartan background, using the Schwinger--DeWitt method of proper-time expansion. The calculation corresponds to a generalization of DeWitt's calculation for a Riemannian background
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Zolotarev, Vladimir A
2009-01-01
Functional models are constructed for commutative systems {A 1 ,A 2 } of bounded linear non-self-adjoint operators which do not contain dissipative operators (which means that ξ 1 A 1 +ξ 2 A 2 is not a dissipative operator for any ξ 1 , ξ 2 element of R). A significant role is played here by the de Branges transform and the function classes occurring in this context. Classes of commutative systems of operators {A 1 ,A 2 } for which such a construction is possible are distinguished. Realizations of functional models in special spaces of meromorphic functions on Riemann surfaces are found, which lead to reasonable analogues of de Branges spaces on these Riemann surfaces. It turns out that the functions E(p) and E-tilde(p) determining the order of growth in de Branges spaces on Riemann surfaces coincide with the well-known Baker-Akhiezer functions. Bibliography: 11 titles.
Explicit solution of Riemann-Hilbert problems for the Ernst equation
Klein, C.; Richter, O.
1998-01-01
Riemann-Hilbert problems are an important solution technique for completely integrable differential equations. They are used to introduce a free function in the solutions which can be used at least in principle to solve initial or boundary value problems. But even if the initial or boundary data can be translated into a Riemann-Hilbert problem, it is in general impossible to obtain explicit solutions. In the case of the Ernst equation, however, this is possible for a large class because the matrix problem can be shown to be gauge equivalent to a scalar one on a hyperelliptic Riemann surface that can be solved in terms of theta functions. As an example we discuss the rigidly rotating dust disk.
Non-uniqueness of admissible weak solutions to the Riemann problem for isentropic Euler equations
Chiodaroli, Elisabetta; Kreml, Ondřej
2018-04-01
We study the Riemann problem for multidimensional compressible isentropic Euler equations. Using the framework developed in Chiodaroli et al (2015 Commun. Pure Appl. Math. 68 1157–90), and based on the techniques of De Lellis and Székelyhidi (2010 Arch. Ration. Mech. Anal. 195 225–60), we extend the results of Chiodaroli and Kreml (2014 Arch. Ration. Mech. Anal. 214 1019–49) and prove that it is possible to characterize a set of Riemann data, giving rise to a self-similar solution consisting of one admissible shock and one rarefaction wave, for which the problem also admits infinitely many admissible weak solutions.
SO(N) WZNW models on higher-genus Riemann surfaces
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Alimohammadi, M.; Arfaei, H.; Bonn Univ.
1993-08-01
With the help of the string functions and fusion rules of SO(2N) 1 , we show that the results on SU(N) 1 correlators on higher-genus Riemann surfaces (HGRS) can be extended to the SO(2N) 1 and other level-one simply-laced WZNW models. Using modular invariance and factorization properties of Green functions we find multipoint correlators of primary and descendant fields of SO(2N+1) 1 WZNW models on higher genus Riemann surfaces. (orig.)
Modular transformations of conformal blocks in WZW models on Riemann surfaces of higher genus
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Miao Li; Ming Yu.
1989-05-01
We derive the modular transformations for conformal blocks in Wess-Zumino-Witten models on Riemann surfaces of higher genus. The basic ingredient consists of using the Chern-Simons theory developed by Witten. We find that the modular transformations generated by Dehn twists are linear combinations of Wilson line operators, which can be expressed in terms of braiding matrices. It can also be shown that modular transformation matrices for g > 0 Riemann surfaces depend only on those for g ≤ 3. (author). 13 refs, 15 figs
Ghil, M.; Balgovind, R.
1979-01-01
The inhomogeneous Cauchy-Riemann equations in a rectangle are discretized by a finite difference approximation. Several different boundary conditions are treated explicitly, leading to algorithms which have overall second-order accuracy. All boundary conditions with either u or v prescribed along a side of the rectangle can be treated by similar methods. The algorithms presented here have nearly minimal time and storage requirements and seem suitable for development into a general-purpose direct Cauchy-Riemann solver for arbitrary boundary conditions.
Exact Riemann solutions of the Ripa model for flat and non-flat bottom topographies
Rehman, Asad; Ali, Ishtiaq; Qamar, Shamsul
2018-03-01
This article is concerned with the derivation of exact Riemann solutions for Ripa model considering flat and non-flat bottom topographies. The Ripa model is a system of shallow water equations accounting for horizontal temperature gradients. In the case of non-flat bottom topography, the mass, momentum and energy conservation principles are utilized to relate the left and right states across the step-type bottom topography. The resulting system of algebraic equations is solved iteratively. Different numerical case studies of physical interest are considered. The solutions obtained from developed exact Riemann solvers are compared with the approximate solutions of central upwind scheme.
Reassessing Riemann's paper on the number of primes less than a given magnitude
Dittrich, Walter
2018-01-01
In this book, the author pays tribute to Bernhard Riemann (1826–1866), mathematician with revolutionary ideas, whose work on the theory of integration, the Fourier transform, the hypergeometric differential equation, etc. contributed immensely to mathematical physics. This book concentrates in particular on Riemann’s only work on prime numbers, including such then new ideas as analytical continuation in the complex plane and the product formula for entire functions. A detailed analysis of the zeros of the Riemann zeta function is presented. The impact of Riemann’s ideas on regularizing infinite values in field theory is also emphasized.
Riemann problems and their application to ultra-relativistic heavy ion collisions
International Nuclear Information System (INIS)
Plohr, B.J.; Sharp, D.H.
1986-07-01
Heavy ion collisions at sufficiently high energies to form quark-gluon plasma are considered. The phase transformation from a quark-gluon phase to hadrons as the nuclear matter cools is modeled as a hydrodynamical flow. Nonlinear waves are the predominant feature of this type of flow and the Riemann problem of a relativistic gas undergoing a phase transformation is explored as a method to numerically model this phase transition process in nuclear matter. The solution of the Riemann problem is outlined and results of preliminary numerical computations of the flow are presented. 10 refs., 2 figs
Local Extrema of the $\\Xi(t)$ Function and The Riemann Hypothesis
Kobayashi, Hisashi
2016-01-01
In the present paper we obtain a necessary and sufficient condition to prove the Riemann hypothesis in terms of certain properties of local extrema of the function $\\Xi(t)=\\xi(\\tfrac{1}{2}+it)$. First, we prove that positivity of all local maxima and negativity of all local minima of $\\Xi(t)$ form a necessary condition for the Riemann hypothesis to be true. After showing that any extremum point of $\\Xi(t)$ is a saddle point of the function $\\Re\\{\\xi(s)\\}$, we prove that the above properties o...
Reduction of 4-dim self dual super Yang-Mills onto super Riemann surfaces
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Mendoza, A.; Restuccia, A.; Martin, I.
1990-05-01
Recently self dual super Yang-Mills over a super Riemann surface was obtained as the zero set of a moment map on the space of superconnections to the dual of the super Lie algebra of gauge transformations. We present a new formulation of 4-dim Euclidean self dual super Yang-Mills in terms of constraints on the supercurvature. By dimensional reduction we obtain the same set of superconformal field equations which define self dual connections on a super Riemann surface. (author). 10 refs
Super-quasi-conformal transformation and Schiffer variation on super-Riemann surface
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Takahasi, Wataru
1990-01-01
A set of equations which characterizes the super-Teichmueller deformations is proposed. It is a supersymmetric extension of the Beltrami equation. Relations between the set of equations and the Schiffer variations with the KN bases are discussed. This application of the KN bases shows the powerfulness of the KN theory in the study of super-Riemann surfaces. (author)
The Great Gorilla Jump: An Introduction to Riemann Sums and Definite Integrals
Sealey, Vicki; Engelke, Nicole
2012-01-01
The great gorilla jump is an activity designed to allow calculus students to construct an understanding of the structure of the Riemann sum and definite integral. The activity uses the ideas of position, velocity, and time to allow students to explore familiar ideas in a new way. Our research has shown that introducing the definite integral as…
Riemann type algebraic structures and their differential-algebraic integrability analysis
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Prykarpatsky A.K.
2010-06-01
Full Text Available The differential-algebraic approach to studying the Lax type integrability of generalized Riemann type equations is devised. The differentiations and the associated invariant differential ideals are analyzed in detail. The approach is also applied to studying the Lax type integrability of the well known Korteweg-de Vries dynamical system.
Infinite conformal symmetries and Riemann-Hilbert transformation in super principal chiral model
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Hao Sanru; Li Wei
1989-01-01
This paper shows a new symmetric transformation - C transformation in super principal chiral model and discover an infinite dimensional Lie algebra related to the Virasoro algebra without central extension. By using the Riemann-Hilbert transformation, the physical origination of C transformation is discussed
International Nuclear Information System (INIS)
Wang Shikun; Xu Kaiwen.
1989-12-01
The superconformal algebras of meromorphic vector fields with multipoles, the central extension and the relevant abelian differential of the third kind on super Riemann sphere were constructed. The background of our theory is concerned with the interaction of closed superstrings. (author). 9 refs
Seeley-De Witt coefficients in a Riemann-Cartan manifold
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Cognola, G.; Zerbini, S.; Istituto Nazionale di Fisica Nucleare, Povo
1988-01-01
A new derivation of the first two coefficients of the heat kernel expansion for a second-order elliptic differential operator on a Riemann-Cartan manifold with arbitrary torsion is given. The expressions are presented in a very compact and tractable form useful for physical applications. Comparisons with other similar results that appeared in the literature are briefly discussed. (orig.)
Asymptotic analysis on a pseudo-Hermitian Riemann-zeta Hamiltonian
Bender, Carl M.; Brody, Dorje C.
2018-04-01
The differential-equation eigenvalue problem associated with a recently-introduced Hamiltonian, whose eigenvalues correspond to the zeros of the Riemann zeta function, is analyzed using Fourier and WKB analysis. The Fourier analysis leads to a challenging open problem concerning the formulation of the eigenvalue problem in the momentum space. The WKB analysis gives the exact asymptotic behavior of the eigenfunction.
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Chau Ling-Lie; Ge Mo-Lin; Teh, Rosy.
1984-09-01
The Baecklund Transformations and the hidden symmetry algebra for Self-Dual Yang-Mills Equations, Landau-Lifshitz equations and the Extended Super Yang-Mills fields (N>2) are discussed on the base of the Regular Riemann-Hilbert Transform and the linearization equations. (author)
Representation theory of current algebra and conformal field theory on Riemann surfaces
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Yamada, Yasuhiko
1989-01-01
We study conformal field theories with current algebra (WZW-model) on general Riemann surfaces based on the integrable representation theory of current algebra. The space of chiral conformal blocks defined as solutions of current and conformal Ward identities is shown to be finite dimensional and satisfies the factorization properties. (author)
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Varaksin, O.L.; Firstov, V.V.; Shapovalov, A.V.; Shirokov, I.V.
1995-01-01
The method of noncommutative integration of linear partial differential equations is used to solve the Klein-Gordon equations in Riemann space, in the case when the set of noncommutating symmetry operators of this equation for a quadratic algebra consists of one second-order operator and several first-order operators. Solutions that do not permit variable separation are presented
Moser, Jan
2015-01-01
In this paper we introduce complicated oscillating system, namely quotient of two multiforms based on Riemann-Siegel formula. We prove that there is an infinite set of metamorphoses of this system (=chrysalis) on critical line $\\sigma=\\frac 12$ into a butterfly (=infinite series of M\\" obius functions in the region of absolute convergence $\\sigma>1$).
Classical and quantum Liouville theory on the Riemann sphere with n>3 punctures (III)
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Shen Jianmin; Sheng Zhengmao; Wang Zhonghua
1992-02-01
We study the Classical and Quantum Liouville theory on the Riemann sphere with n>3 punctures. We get the quantum exchange algebra relations between the chiral components in the Liouville theory from our assumption on the principle of quantization. (author). 5 refs
Fourier-Laplace transform of irreducible regular differential systems on the Riemann sphere
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Sabbah, C
2004-01-01
It is shown that the Fourier-Laplace transform of an irreducible regular differential system on the Riemann sphere underlies a polarizable regular twistor D-module if one considers only the part at finite distance. The associated holomorphic bundle defined away from the origin of the complex plane is therefore equipped with a natural harmonic metric having a tame behaviour near the origin
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Meina Sun
2016-05-01
Full Text Available We study the Riemann problem for a non-strictly hyperbolic system of conservation laws under the linear approximations of flux functions with three parameters. The approximated system also belongs to the type of triangular systems of conservation laws and this approximation does not change the structure of Riemann solutions to the original system. Furthermore, it is proven that the Riemann solutions to the approximated system converge to the corresponding ones to the original system as the perturbation parameter tends to zero.
Directory of Open Access Journals (Sweden)
Kyncl Martin
2017-01-01
Full Text Available We work with the system of partial differential equations describing the non-stationary compressible turbulent fluid flow. It is a characteristic feature of the hyperbolic equations, that there is a possible raise of discontinuities in solutions, even in the case when the initial conditions are smooth. The fundamental problem in this area is the solution of the so-called Riemann problem for the split Euler equations. It is the elementary problem of the one-dimensional conservation laws with the given initial conditions (LIC - left-hand side, and RIC - right-hand side. The solution of this problem is required in many numerical methods dealing with the 2D/3D fluid flow. The exact (entropy weak solution of this hyperbolical problem cannot be expressed in a closed form, and has to be computed by an iterative process (to given accuracy, therefore various approximations of this solution are being used. The complicated Riemann problem has to be further modified at the close vicinity of boundary, where the LIC is given, while the RIC is not known. Usually, this boundary problem is being linearized, or roughly approximated. The inaccuracies implied by these simplifications may be small, but these have a huge impact on the solution in the whole studied area, especially for the non-stationary flow. Using the thorough analysis of the Riemann problem we show, that the RIC for the local problem can be partially replaced by the suitable complementary conditions. We suggest such complementary conditions accordingly to the desired preference. This way it is possible to construct the boundary conditions by the preference of total values, by preference of pressure, velocity, mass flow, temperature. Further, using the suitable complementary conditions, it is possible to simulate the flow in the vicinity of the diffusible barrier. On the contrary to the initial-value Riemann problem, the solution of such modified problems can be written in the closed form for some
International Nuclear Information System (INIS)
Bolte, J.
1992-08-01
The Selberg trace formula for automorphic forms of weight m ε- Z, on bordered Riemann surfaces is developed. The trace formula is formulated for arbitrary Fuchsian groups of the first kind which include hyperbolic, elliptic and parabolic conjugacy classes. In the case of compact bordered Riemann surfaces we can explicitly evaluate determinants of Maass-Laplacians for both Dirichlet and Neumann boundary-conditions, respectively. Some implications for the open bosonic string theory are mentioned. (orig.)
International Nuclear Information System (INIS)
Stachel, J.
1977-01-01
A first-order Lagrangian is given, from which follow the definitions of the fully covariant form of the Riemann tensor Rsub(μνkappalambda) in terms of the affine connection and metric; the definition of the affine connection in terms of the metric; the Einstein field equations; and the definition of a set of gravitational 'superpotentials' closely connected with the Komar conservation laws (Phys. Rev.; 113:934 (1959)). Substitution of the definition of the affine connection into this Lagrangian results in a second-order Lagrangian, from which follow the definition of the fully covariant Riemann tensor in terms of the metric, the Einstein equations, and the definition of the gravitational 'superpotentials'. (author)
An Exact, Compressible One-Dimensional Riemann Solver for General, Convex Equations of State
Energy Technology Data Exchange (ETDEWEB)
Kamm, James Russell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2015-03-05
This note describes an algorithm with which to compute numerical solutions to the one- dimensional, Cartesian Riemann problem for compressible flow with general, convex equations of state. While high-level descriptions of this approach are to be found in the literature, this note contains most of the necessary details required to write software for this problem. This explanation corresponds to the approach used in the source code that evaluates solutions for the 1D, Cartesian Riemann problem with a JWL equation of state in the ExactPack package [16, 29]. Numerical examples are given with the proposed computational approach for a polytropic equation of state and for the JWL equation of state.
Riemann-Hilbert treatment of Liouville theory on the torus: the general case
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Menotti, Pietro
2011-01-01
We extend the previous treatment of Liouville theory on the torus to the general case in which the distribution of charges is not necessarily symmetric. This requires the concept of Fuchsian differential equation on Riemann surfaces. We show through a group theoretic argument that the Heun parameter and a weight constant are sufficient to satisfy all monodromy conditions. We then apply the technique of differential equations on a Riemann surface to the two-point function on the torus in which one source is arbitrary and the other small. As a byproduct, we give in terms of quadratures the exact Green function on the square and on the rhombus with opening angle 2π/6 in the background of the field generated by an arbitrary charge.
Ship-induced solitary Riemann waves of depression in Venice Lagoon
International Nuclear Information System (INIS)
Parnell, Kevin E.; Soomere, Tarmo; Zaggia, Luca; Rodin, Artem; Lorenzetti, Giuliano; Rapaglia, John; Scarpa, Gian Marco
2015-01-01
We demonstrate that ships of moderate size, sailing at low depth Froude numbers (0.37–0.5) in a navigation channel surrounded by shallow banks, produce depressions with depths up to 2.5 m. These depressions (Bernoulli wakes) propagate as long-living strongly nonlinear solitary Riemann waves of depression substantial distances into Venice Lagoon. They gradually become strongly asymmetric with the rear of the depression becoming extremely steep, similar to a bore. As they are dynamically similar, air pressure fluctuations moving over variable-depth coastal areas could generate meteorological tsunamis with a leading depression wave followed by a devastating bore-like feature. - Highlights: • Unprecedently deep long-living ship-induced waves of depression detected. • Such waves are generated in channels with side banks under low Froude numbers. • The propagation of these waves is replicated using Riemann waves. • Long-living waves of depression form bore-like features at rear slope
Instanton calculus without equations of motion: semiclassics from monodromies of a Riemann surface
Gulden, Tobias; Janas, Michael; Kamenev, Alex
2015-02-01
Instanton calculations in semiclassical quantum mechanics rely on integration along trajectories which solve classical equations of motion. However in systems with higher dimensionality or complexified phase space these are rarely attainable. A prime example are spin-coherent states which are used e.g. to describe single molecule magnets (SMM). We use this example to develop instanton calculus which does not rely on explicit solutions of the classical equations of motion. Energy conservation restricts the complex phase space to a Riemann surface of complex dimension one, allowing to deform integration paths according to Cauchy’s integral theorem. As a result, the semiclassical actions can be evaluated without knowing actual classical paths. Furthermore we show that in many cases such actions may be solely derived from monodromy properties of the corresponding Riemann surface and residue values at its singular points. As an example, we consider quenching of tunneling processes in SMM by an applied magnetic field.
Ship-induced solitary Riemann waves of depression in Venice Lagoon
Energy Technology Data Exchange (ETDEWEB)
Parnell, Kevin E. [College of Marine and Environmental Sciences and Centre for Tropical Environmental and Sustainability Sciences, James Cook University, Queensland 4811 (Australia); Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Soomere, Tarmo, E-mail: soomere@cs.ioc.ee [Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn (Estonia); Zaggia, Luca [Institute of Marine Sciences, National Research Council, Castello 2737/F, 30122 Venice (Italy); Rodin, Artem [Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Lorenzetti, Giuliano [Institute of Marine Sciences, National Research Council, Castello 2737/F, 30122 Venice (Italy); Rapaglia, John [Sacred Heart University Department of Biology, 5151 Park Avenue, Fairfield, CT 06825 (United States); Scarpa, Gian Marco [Università Ca' Foscari, Dorsoduro 3246, 30123 Venice (Italy)
2015-03-06
We demonstrate that ships of moderate size, sailing at low depth Froude numbers (0.37–0.5) in a navigation channel surrounded by shallow banks, produce depressions with depths up to 2.5 m. These depressions (Bernoulli wakes) propagate as long-living strongly nonlinear solitary Riemann waves of depression substantial distances into Venice Lagoon. They gradually become strongly asymmetric with the rear of the depression becoming extremely steep, similar to a bore. As they are dynamically similar, air pressure fluctuations moving over variable-depth coastal areas could generate meteorological tsunamis with a leading depression wave followed by a devastating bore-like feature. - Highlights: • Unprecedently deep long-living ship-induced waves of depression detected. • Such waves are generated in channels with side banks under low Froude numbers. • The propagation of these waves is replicated using Riemann waves. • Long-living waves of depression form bore-like features at rear slope.
Bernhard Riemann 1826-1866 Turning Points in the Conception of Mathematics
Laugwitz, Detlef
2008-01-01
The name of Bernard Riemann is well known to mathematicians and physicists around the world. College students encounter the Riemann integral early in their studies. Real and complex function theories are founded on Riemann’s work. Einstein’s theory of gravitation would be unthinkable without Riemannian geometry. In number theory, Riemann’s famous conjecture stands as one of the classic challenges to the best mathematical minds and continues to stimulate deep mathematical research. The name is indelibly stamped on the literature of mathematics and physics. This book, originally written in German and presented here in an English-language translation, examines Riemann’s scientific work from a single unifying perspective. Laugwitz describes Riemann’s development of a conceptual approach to mathematics at a time when conventional algorithmic thinking dictated that formulas and figures, rigid constructs, and transformations of terms were the only legitimate means of studying mathematical objects. David Hi...
Averages of ratios of the Riemann zeta-function and correlations of divisor sums
Conrey, Brian; Keating, Jonathan P.
2017-10-01
Nonlinearity has published articles containing a significant number-theoretic component since the journal was first established. We examine one thread, concerning the statistics of the zeros of the Riemann zeta function. We extend this by establishing a connection between the ratios conjecture for the Riemann zeta-function and a conjecture concerning correlations of convolutions of Möbius and divisor functions. Specifically, we prove that the ratios conjecture and an arithmetic correlations conjecture imply the same result. This provides new support for the ratios conjecture, which previously had been motivated by analogy with formulae in random matrix theory and by a heuristic recipe. Our main theorem generalises a recent calculation pertaining to the special case of two-over-two ratios.
Flux quantization and quantum mechanics on Riemann surfaces in an external magnetic field
International Nuclear Information System (INIS)
Bolte, J.; Steiner, F.
1990-10-01
We investigate the possibility to apply an external constant magnetic field to a quantum mechanical system consisting of a particle moving on a compact or non-compact two-dimensional manifold of constant negative Gaussian curvature and of finite volume. For the motion on compact Riemann surfaces we find that a consistent formulation is only possible if the magnetic flux is quantized, as it is proportional to the (integrated) first Chern class of a certain complex line bundle over the manifold. In the case of non-compact surfaces of finite volume we obtain the striking result that the magnetic flux has to vanish identically due to the theorem that any holomorphic line bundle over a non-compact Riemann surface is holomorphically trivial. (orig.)
International Nuclear Information System (INIS)
van Nieuwenhuizen, P.; Wu, C.C.
1977-01-01
The lowest order quantum corrections to pure gravitation are finite because there exists an integral relation between products of two Riemann tensors (the Gauss--Bonnet theorem). In this article several algebraic and integral relations are determined between products of three Riemann tensors in four- and six-dimensional spacetime. In both cases, one is left with only one invariant when R/sub μ//sub ν/=0, viz., ∫ (-g) 1 / 2 (R/sub b//sub β//sub μ//sub ν/R/sup μ//sup ν//sup rho//sup sigma/R/sub rho//sub sigma/ /sup α//sup β/).It is explicitly shown that this invariant does not vanish, even when R/sub μ//sub ν/=0. Consequently, the two-loop quantum corrections to pure gravitation will only be finite if, due to miraculous cancellation, the coefficient of this invariant vanishes
From Euclidean to Minkowski space with the Cauchy-Riemann equations
International Nuclear Information System (INIS)
Gimeno-Segovia, Mercedes; Llanes-Estrada, Felipe J.
2008-01-01
We present an elementary method to obtain Green's functions in non-perturbative quantum field theory in Minkowski space from Green's functions calculated in Euclidean space. Since in non-perturbative field theory the analytical structure of amplitudes often is unknown, especially in the presence of confined fields, dispersive representations suffer from systematic uncertainties. Therefore, we suggest to use the Cauchy-Riemann equations, which perform the analytical continuation without assuming global information on the function in the entire complex plane, but only in the region through which the equations are solved. We use as example the quark propagator in Landau gauge quantum chromodynamics, which is known from lattice and Dyson-Schwinger studies in Euclidean space. The drawback of the method is the instability of the Cauchy-Riemann equations against high-frequency noise,which makes it difficult to achieve good accuracy. We also point out a few curious details related to the Wick rotation. (orig.)
On Riemann boundary value problems for null solutions of the two dimensional Helmholtz equation
Bory Reyes, Juan; Abreu Blaya, Ricardo; Rodríguez Dagnino, Ramón Martin; Kats, Boris Aleksandrovich
2018-01-01
The Riemann boundary value problem (RBVP to shorten notation) in the complex plane, for different classes of functions and curves, is still widely used in mathematical physics and engineering. For instance, in elasticity theory, hydro and aerodynamics, shell theory, quantum mechanics, theory of orthogonal polynomials, and so on. In this paper, we present an appropriate hyperholomorphic approach to the RBVP associated to the two dimensional Helmholtz equation in R^2 . Our analysis is based on a suitable operator calculus.
Jet Riemann-Lagrange Geometry Applied to Evolution DEs Systems from Economy
Neagu, Mircea
2007-01-01
The aim of this paper is to construct a natural Riemann-Lagrange differential geometry on 1-jet spaces, in the sense of nonlinear connections, generalized Cartan connections, d-torsions, d-curvatures, jet electromagnetic fields and jet Yang-Mills energies, starting from some given non-linear evolution DEs systems modelling economic phenomena, like the Kaldor model of the bussines cycle or the Tobin-Benhabib-Miyao model regarding the role of money on economic growth.
Temperature duality on Riemann surface and cosmological solutions for genus g = 1 and 2
International Nuclear Information System (INIS)
Yan Jun; Wang Shunjin
1999-01-01
A bosonic string model at finite temperature on the gravitation g μν and the dilaton φ background field is examined. Moreover, the duality relation of energy momentum tensor on high genus Riemann surface is derived. At the same time, the temperature duality invariance for the action of string gas matter is proved in 4-D Robertson-Walker metric, the string cosmological solutions and temperature duality of the equations of motion for genus g = 1 and 2 are also investigated
Stability of the isentropic Riemann solutions of the full multidimensional Euler system
Czech Academy of Sciences Publication Activity Database
Feireisl, Eduard; Kreml, Ondřej; Vasseur, A.
2015-01-01
Roč. 47, č. 3 (2015), s. 2416-2425 ISSN 0036-1410 R&D Projects: GA ČR GA13-00522S EU Projects: European Commission(XE) 320078 - MATHEF Institutional support: RVO:67985840 Keywords : Euler system * isentropic solutions * Riemann problem * rarefaction wave Subject RIV: BA - General Mathematics Impact factor: 1.486, year: 2015 http://epubs.siam.org/doi/abs/10.1137/140999827
Codomains for the Cauchy-Riemann and Laplace operators in ℝ2
Directory of Open Access Journals (Sweden)
Lloyd Edgar S. Moyo
2008-01-01
Full Text Available A codomain for a nonzero constant-coefficient linear partial differential operator P(∂ with fundamental solution E is a space of distributions T for which it is possible to define the convolution E*T and thus solving the equation P(∂S=T. We identify codomains for the Cauchy-Riemann operator in ℝ2 and Laplace operator in ℝ2 . The convolution is understood in the sense of the S′-convolution.
Representation of symmetric metric connection via Riemann-Christoffel curvature tensor
International Nuclear Information System (INIS)
Selikhov, A.V.
1989-01-01
Bivector σ-bar μ ν ' which is the Jacoby matrix of the transformation to the Riemanian coordinates is considered in the paper. Basing on the dual nature of σ-bar μ ν ' the representation of metric connection (Christoffel symbols) have been obtained at the Riemanian coordinates via Riemann-Christoffel curvature tensor; the covariant conserved four-momentum in the general theory of relativity have been constructed. 11 refs
International Nuclear Information System (INIS)
Tan, Zhiqiang; Wilson, D.; Varghese, P.L.
1997-01-01
We consider an extension of the ordinary Riemann problem and present an efficient approximate solution that can be used to improve the calculations of aerodynamic forces on an accelerating body. The method is demonstrated with one-dimensional examples where the Euler equations and the body motion are solved in the non-inertial co-ordinate frame fixed to the accelerating body. 8 refs., 6 figs
Fermions on a Riemann surface and the Kadomtsev-Petviashvili equation
International Nuclear Information System (INIS)
Zabrodin, A.V.
1989-01-01
It is shown that the S matrix of free massless fermions on a Riemann surface of finite genus generates quasiperiodic solutions of the Kadomtsev-Petviashvili equation. An operator that changes the genus of a solution is constructed, and the law of composition of such operators is discussed. The construction is a generalization of the well-known operator approach in the case of soliton solutions to the general case of quasiperiodic τ functions
A novel supersymmetry in 2-dimensional Yang-Mills theory on Riemann surfaces
International Nuclear Information System (INIS)
Soda, Jiro
1991-02-01
We find a novel supersymmetry in 2-dimensional Maxwell and Yang-Mills theories. Using this supersymmetry, it is shown that the 2-dimensional Euclidean pure gauge theory on a closed Riemann surface Σ can be reduced to a topological field theory which is the 3-dimensional Chern-Simons gauge theory in the special space-time topology Σ x R. Related problems are also discussed. (author)
Cálculo de áreas mediante la suma de Riemann con la TI-83
Lupiáñez, José Luis
2002-01-01
En este artículo presentamos una actividad para introducir el cálculo del área que encierra una curva, basada en la Suma de Riemann, y que puede realizarse con la calculadora TI-83. El planteamiento de la actividad permite estudiar varias funciones sin perder tiempo en tediosos cálculos, con idea de observar lo acertado de este método de aproximación.
Riemann zeros and phase transitions via the spectral operator on fractal strings
International Nuclear Information System (INIS)
Herichi, Hafedh; Lapidus, Michel L
2012-01-01
The spectral operator was introduced by Lapidus and van Frankenhuijsen (2006 Fractal Geometry, Complex Dimensions and Zeta Functions: Geometry and Spectra of Fractal Strings) in their reinterpretation of the earlier work of Lapidus and Maier (1995 J. Lond. Math. Soc. 52 15–34) on inverse spectral problems and the Riemann hypothesis. In essence, it is a map that sends the geometry of a fractal string onto its spectrum. In this review, we present the rigorous functional analytic framework given by Herichi and Lapidus (2012) and within which to study the spectral operator. Furthermore, we give a necessary and sufficient condition for the invertibility of the spectral operator (in the critical strip) and therefore obtain a new spectral and operator-theoretic reformulation of the Riemann hypothesis. More specifically, we show that the spectral operator is quasi-invertible (or equivalently, that its truncations are invertible) if and only if the Riemann zeta function ζ(s) does not have any zeros on the vertical line Re(s) = c. Hence, it is not invertible in the mid-fractal case when c= 1/2 , and it is quasi-invertible everywhere else (i.e. for all c ∈ (0, 1) with c≠ 1/2 ) if and only if the Riemann hypothesis is true. We also show the existence of four types of (mathematical) phase transitions occurring for the spectral operator at the critical fractal dimension c= 1/2 and c = 1 concerning the shape of the spectrum, its boundedness, its invertibility as well as its quasi-invertibility. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker’s 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’. (review)
Vertex operators, non-abelian orbifolds and the Riemann-Hilbert problem
International Nuclear Information System (INIS)
Gato, B.; Massachusetts Inst. of Tech., Cambridge
1990-01-01
We show how to construct the oscillator part of vertex operators for the bosonic string moving on non-abelian orbifolds, using the conserved charges method. When the three-string vertices are twisted by non-commuting group elements, the construction of the conserved charges becomes the Riemann-Hilbert problem with monodromy matrices given by the twists. This is solvable for any given configuration and any non-abelian orbifold. (orig.)
Czech Academy of Sciences Publication Activity Database
Chiodaroli, E.; Kreml, Ondřej
2018-01-01
Roč. 31, č. 4 (2018), s. 1441-1460 ISSN 0951-7715 R&D Projects: GA ČR(CZ) GJ17-01694Y Institutional support: RVO:67985840 Keywords : Riemann problem * non-uniqueness * weak solutions Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.767, year: 2016 http://iopscience.iop.org/ article /10.1088/1361-6544/aaa10d/meta
Czech Academy of Sciences Publication Activity Database
Chiodaroli, E.; Kreml, Ondřej
2018-01-01
Roč. 31, č. 4 (2018), s. 1441-1460 ISSN 0951-7715 R&D Projects: GA ČR(CZ) GJ17-01694Y Institutional support: RVO:67985840 Keywords : Riemann problem * non-uniqueness * weak solutions Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.767, year: 2016 http://iopscience.iop.org/article/10.1088/1361-6544/aaa10d/meta
Directory of Open Access Journals (Sweden)
Abdon Atangana
2014-01-01
Full Text Available The notion of uncertainty in groundwater hydrology is of great importance as it is known to result in misleading output when neglected or not properly accounted for. In this paper we examine this effect in groundwater flow models. To achieve this, we first introduce the uncertainties functions u as function of time and space. The function u accounts for the lack of knowledge or variability of the geological formations in which flow occur (aquifer in time and space. We next make use of Riemann-Liouville fractional derivatives that were introduced by Kobelev and Romano in 2000 and its approximation to modify the standard version of groundwater flow equation. Some properties of the modified Riemann-Liouville fractional derivative approximation are presented. The classical model for groundwater flow, in the case of density-independent flow in a uniform homogeneous aquifer is reformulated by replacing the classical derivative by the Riemann-Liouville fractional derivatives approximations. The modified equation is solved via the technique of green function and the variational iteration method.
Levine, Rachel; Krenning, Eric P
2017-09-01
In nuclear medicine, the term theranostics describes the combination of therapy and diagnostic imaging. In practice, this concept dates back more than 50 years; however, among the most successful examples of theranostics are peptide receptor scintigraphy and peptide receptor radionuclide therapy of neuroendocrine tumors. The development of these modalities through the radiolabeling of somatostatin analogs with various radionuclides has led to a revolution in patient management and established a foundation for expansion of the theranostic principle into other oncology indications. This article provides a review of the evolution and development of the theranostic radionuclide approach to the management of neuroendocrine tumors, as described by the inventor of this technique, Eric P. Krenning, in an interview with Rachel Levine. © 2017 by the Society of Nuclear Medicine and Molecular Imaging.
Balsara, Dinshaw S.; Dumbser, Michael
2015-04-01
Multidimensional Riemann solvers that have internal sub-structure in the strongly-interacting state have been formulated recently (D.S. Balsara (2012, 2014) [5,16]). Any multidimensional Riemann solver operates at the grid vertices and takes as its input all the states from its surrounding elements. It yields as its output an approximation of the strongly interacting state, as well as the numerical fluxes. The multidimensional Riemann problem produces a self-similar strongly-interacting state which is the result of several one-dimensional Riemann problems interacting with each other. To compute this strongly interacting state and its higher order moments we propose the use of a Galerkin-type formulation to compute the strongly interacting state and its higher order moments in terms of similarity variables. The use of substructure in the Riemann problem reduces numerical dissipation and, therefore, allows a better preservation of flow structures, like contact and shear waves. In this second part of a series of papers we describe how this technique is extended to unstructured triangular meshes. All necessary details for a practical computer code implementation are discussed. In particular, we explicitly present all the issues related to computational geometry. Because these Riemann solvers are Multidimensional and have Self-similar strongly-Interacting states that are obtained by Consistency with the conservation law, we call them MuSIC Riemann solvers. (A video introduction to multidimensional Riemann solvers is available on http://www.elsevier.com/xml/linking-roles/text/html". The MuSIC framework is sufficiently general to handle general nonlinear systems of hyperbolic conservation laws in multiple space dimensions. It can also accommodate all self-similar one-dimensional Riemann solvers and subsequently produces a multidimensional version of the same. In this paper we focus on unstructured triangular meshes. As examples of different systems of conservation laws we
International Nuclear Information System (INIS)
Toumi, I.
1990-04-01
This thesis is devoted to the study of the Riemann problem and the construction of Godunov type numerical schemes for one or two dimensional two-phase flow models. In the first part, we study the Riemann problem for the well-known Drift-Flux, model which has been widely used for the analysis of thermal hydraulics transients. Then we use this study to construct approximate Riemann solvers and we describe the corresponding Godunov type schemes for simplified equation of state. For computation of complex two-phase flows, a weak formulation of Roe's approximate Riemann solver, which gives a method to construct a Roe-averaged jacobian matrix with a general equation of state, is proposed. For two-dimensional flows, the developed methods are based upon an approximate solver for a two-dimensional Riemann problem, according to Harten-Lax-Van Leer principles. The numerical results for standard test problems show the good behaviour of these numerical schemes for a wide range of flow conditions [fr
Riemann solvers for multi-component gas mixtures with temperature dependent heat capacities
International Nuclear Information System (INIS)
Beccantini, A.
2001-01-01
This thesis represents a contribution to the development of upwind splitting schemes for the Euler equations for ideal gaseous mixtures and their investigation in computing multidimensional flows in irregular geometries. In the preliminary part we develop and investigate the parameterization of the shock and rarefaction curves in the phase space. Then, we apply them to perform some field-by-field decompositions of the Riemann problem: the entropy-respecting one, the one which supposes that genuinely-non-linear (GNL) waves are both shocks (shock-shock one) and the one which supposes that GNL waves are both rarefactions (rarefaction-rarefaction one). We emphasize that their analysis is fundamental in Riemann solvers developing: the simpler the field-by-field decomposition, the simpler the Riemann solver based on it. As the specific heat capacities of the gases depend on the temperature, the shock-shock field-by-field decomposition is the easiest to perform. Then, in the second part of the thesis, we develop an upwind splitting scheme based on such decomposition. Afterwards, we investigate its robustness, precision and CPU-time consumption, with respect to some of the most popular upwind splitting schemes for polytropic/non-polytropic ideal gases. 1-D test-cases show that this scheme is both precise (exact capturing of stationary shock and stationary contact) and robust in dealing with strong shock and rarefaction waves. Multidimensional test-cases show that it suffers from some of the typical deficiencies which affect the upwind splitting schemes capable of exact capturing stationary contact discontinuities i.e the developing of non-physical instabilities in computing strong shock waves. In the final part, we use the high-order multidimensional solver here developed to compute fully-developed detonation flows. (author)
Fractional parts and their relations to the values of the Riemann zeta function
Alabdulmohsin, Ibrahim
2017-09-06
A well-known result, due to Dirichlet and later generalized by de la Vallée–Poussin, expresses a relationship between the sum of fractional parts and the Euler–Mascheroni constant. In this paper, we prove an asymptotic relationship between the summation of the products of fractional parts with powers of integers on the one hand, and the values of the Riemann zeta function, on the other hand. Dirichlet’s classical result falls as a particular case of this more general theorem.
Fractional parts and their relations to the values of the Riemann zeta function
Alabdulmohsin, Ibrahim
2017-01-01
A well-known result, due to Dirichlet and later generalized by de la Vallée–Poussin, expresses a relationship between the sum of fractional parts and the Euler–Mascheroni constant. In this paper, we prove an asymptotic relationship between the summation of the products of fractional parts with powers of integers on the one hand, and the values of the Riemann zeta function, on the other hand. Dirichlet’s classical result falls as a particular case of this more general theorem.
Harada, Hiromitsu; Mouchet, Amaury; Shudo, Akira
2017-10-01
The topology of complex classical paths is investigated to discuss quantum tunnelling splittings in one-dimensional systems. Here the Hamiltonian is assumed to be given as polynomial functions, so the fundamental group for the Riemann surface provides complete information on the topology of complex paths, which allows us to enumerate all the possible candidates contributing to the semiclassical sum formula for tunnelling splittings. This naturally leads to action relations among classically disjoined regions, revealing entirely non-local nature in the quantization condition. The importance of the proper treatment of Stokes phenomena is also discussed in Hamiltonians in the normal form.
Loss of hyperbolicity changes the number of wave groups in Riemann problems
Vítor Matos; Julio D. Silva; Dan Marchesin
2016-01-01
Themain goal of ourwork is to showthat there exists a class of 2×2 Riemann problems for which the solution comprises a singlewave group for an open set of initial conditions. This wave group comprises a 1-rarefaction joined to a 2-rarefaction, not by an intermediate state, but by a doubly characteristic shock, 1-left and 2-right characteristic. In order to ensure that perturbations of initial conditions do not destroy the adjacency of the waves, local transversality between a composite curve ...
The motion of a classical spinning point particle in a Riemann-Cartan space-time
International Nuclear Information System (INIS)
Amorim, R.
1983-01-01
A consistent set of equations of motion for classical charged point particles with spin and magnetic dipole moment in a Riemann-Cartan space-time is generated from a generalized Lagrangean formalism. The equations avoid the spurius free helicoidal solutions and at the same time conserve the canonical condition of normalization of the 4-velocity. The 4-velocity and the mechanical moment are paralell in this theory, where the condition of orthogonality between the spin and the 4-velocity is treated as a non-holonomic one. (Author) [pt
Applications of Wirtinger Inequalities on the Distribution of Zeros of the Riemann Zeta-Function
Directory of Open Access Journals (Sweden)
Saker SamirH
2010-01-01
Full Text Available On the hypothesis that the th moments of the Hardy -function are correctly predicted by random matrix theory and the moments of the derivative of are correctly predicted by the derivative of the characteristic polynomials of unitary matrices, we establish new large spaces between the zeros of the Riemann zeta-function by employing some Wirtinger-type inequalities. In particular, it is obtained that which means that consecutive nontrivial zeros often differ by at least 6.1392 times the average spacing.
A Riemann-Hilbert approach to the inverse problem for the Stark operator on the line
Its, A.; Sukhanov, V.
2016-05-01
The paper is concerned with the inverse scattering problem for the Stark operator on the line with a potential from the Schwartz class. In our study of the inverse problem, we use the Riemann-Hilbert formalism. This allows us to overcome the principal technical difficulties which arise in the more traditional approaches based on the Gel’fand-Levitan-Marchenko equations, and indeed solve the problem. We also produce a complete description of the relevant scattering data (which have not been obtained in the previous works on the Stark operator) and establish the bijection between the Schwartz class potentials and the scattering data.
The transition from regular to irregular motions, explained as travel on Riemann surfaces
International Nuclear Information System (INIS)
Calogero, F; Santini, P M; Gomez-Ullate, D; Sommacal, M
2005-01-01
We introduce and discuss a simple Hamiltonian dynamical system, interpretable as a three-body problem in the (complex) plane and providing the prototype of a mechanism explaining the transition from regular to irregular motions as travel on Riemann surfaces. The interest of this phenomenology-illustrating the onset in a deterministic context of irregular motions-is underlined by its generality, suggesting its eventual relevance to understand natural phenomena and experimental investigations. Here only some of our main findings are reported, without detailing their proofs: a more complete presentation will be published elsewhere
Riemann-Hilbert approach to the time-dependent generalized sine kernel
Energy Technology Data Exchange (ETDEWEB)
Kozlowski, K.K.
2010-12-15
We derive the leading asymptotic behavior and build a new series representation for the Fredholm determinant of integrable integral operators appearing in the representation of the time and distance dependent correlation functions of integrable models described by a six-vertex R-matrix. This series representation opens a systematic way for the computation of the long-time, long-distance asymptotic expansion for the correlation functions of the aforementioned integrable models away from their free fermion point. Our method builds on a Riemann-Hilbert based analysis. (orig.)
Prykarpatsky, Yarema A.; Artemovych, Orest D.; Pavlov, Maxim V.; Prykarpatski, Anatolij K.
2013-06-01
A differential-algebraic approach to studying the Lax-type integrability of the generalized Riemann-type hydrodynamic hierarchy, proposed recently by O. D. Artemovych, M. V. Pavlov, Z. Popowicz and A. K. Prykarpatski, is developed. In addition to the Lax-type representation, found before by Z. Popowicz, a closely related representation is constructed in exact form by means of a new differential-functional technique. The bi-Hamiltonian integrability and compatible Poisson structures of the generalized Riemann type hierarchy are analyzed by means of the symplectic and gradient-holonomic methods. An application of the devised differential-algebraic approach to other Riemann and Vakhnenko type hydrodynamic systems is presented.
Towards a theory of chaos explained as travel on Riemann surfaces
International Nuclear Information System (INIS)
Calogero, F; Santini, P M; Gomez-Ullate, D; Sommacal, M
2009-01-01
We investigate the dynamics defined by a set of three coupled first-order ODEs. It is shown that the system can be reduced to quadratures which can be expressed in terms of elementary functions. Despite the integrable character of the model, the general solution is a multiple-valued function of time (considered as a complex variable), and we investigate the position and nature of its branch points. In the semi-symmetric case (g 1 = g 2 ≠ g 3 ), for rational values of the coupling constants the system is isochronous and explicit formulae for the period of the solutions can be given. For irrational values, the motions are confined but feature aperiodic motion with sensitive dependence on initial conditions. The system shows a rich dynamical behaviour that can be understood in quantitative detail since a global description of the Riemann surface associated with the solutions can be achieved. The details of the description of the Riemann surface are postponed to a forthcoming publication. This toy model is meant to provide a paradigmatic first step towards understanding a certain novel kind of chaotic behaviour
Do extended objects move along the geodesics in the Riemann space-time
International Nuclear Information System (INIS)
Denisov, V.I.; Logunov, A.A.; Mestvirishvili, M.A.
1981-01-01
Movement of an extended self-gravitating body in the gravitational field of another distant body is studied in the postnewtonian approximation of arbitrary metrical gravitational theory. Comparison of the mass center acceleration of the extended body with the acceleration of a point body moving in the Riemann space-time, the metrics of which is formally equivalent to the metrics of two moving extended bodies, shows that in any metrical gravitation theory with conservation laws of energy and momentum of the matter and gravitational field taken together, the mass center of the extended body does not, in general case, move along the geodesics of the Riemann space-time. Application of the general formulas obtained to the system Sun-Earth combined with the experimental data of the lunar laser ranging, shows that the Earth in its orbital motion is oscillating with respect to reference geodesics, with the period about one hour and the amplitude not less than 10 -2 cm. This amplitude is of the postnewtonian magnitude and as a consequence, the deviation of the Earth movement from the geodesical movement can be observed in the experiment possessing the postnewtonian accuracy. The difference between the acceleration of the Earth mass center and that of a test body in the postnewtonian approximation is equal to 10 -7 part of the Earth acceleration. The ratio of the passive gravitational mass of the Earth (defined according to Will) and its inert mass differs from 1 by 10 -8 approximately [ru
Non-supersymmetric matrix strings from generalized Yang-Mills theory on arbitrary Riemann surfaces
International Nuclear Information System (INIS)
Billo, M.; D'Adda, A.; Provero, P.
2000-01-01
We quantize pure 2d Yang-Mills theory on an arbitrary Riemann surface in the gauge where the field strength is diagonal. Twisted sectors originate, as in Matrix string theory, from permutations of the eigenvalues around homotopically non-trivial loops. These sectors, that must be discarded in the usual quantization due to divergences occurring when two eigenvalues coincide, can be consistently kept if one modifies the action by introducing a coupling of the field strength to the space-time curvature. This leads to a generalized Yang-Mills theory whose action reduces to the usual one in the limit of zero curvature. After integrating over the non-diagonal components of the gauge fields, the theory becomes a free string theory (sum over unbranched coverings) with a U(1) gauge theory on the world-sheet. This is shown to be equivalent to a lattice theory with a gauge group which is the semi-direct product of S N and U(1) N . By using well known results on the statistics of coverings, the partition function on arbitrary Riemann surfaces and the kernel functions on surfaces with boundaries are calculated. Extensions to include branch points and non-abelian groups on the world-sheet are briefly commented upon
Indian Academy of Sciences (India)
and that this should be true, no matter how the in- terval [a, b] is subdivided. ..... Moreover, J: 1 is the unique number with this property. We do not know which ..... as some of our previous demonstrations illustrate, the details of the argument ...
Energy Technology Data Exchange (ETDEWEB)
Toumi, I.; Kumbaro, A.; Paillere, H
1999-07-01
These course notes, presented at the 30. Von Karman Institute Lecture Series in Computational Fluid Dynamics, give a detailed and through review of upwind differencing methods for two-phase flow models. After recalling some fundamental aspects of two-phase flow modelling, from mixture model to two-fluid models, the mathematical properties of the general 6-equation model are analysed by examining the Eigen-structure of the system, and deriving conditions under which the model can be made hyperbolic. The following chapters are devoted to extensions of state-of-the-art upwind differencing schemes such as Roe's Approximate Riemann Solver or the Characteristic Flux Splitting method to two-phase flow. Non-trivial steps in the construction of such solvers include the linearization, the treatment of non-conservative terms and the construction of a Roe-type matrix on which the numerical dissipation of the schemes is based. Extension of the 1-D models to multi-dimensions in an unstructured finite volume formulation is also described; Finally, numerical results for a variety of test-cases are shown to illustrate the accuracy and robustness of the methods. (authors)
National Oceanic and Atmospheric Administration, Department of Commerce — Chemical and physical oceanographic profile data were collected aboard the Rachel Bordelon in the Gulf of Mexico from 2010-09-04 to 2010-09-13 in response to the...
Energy Technology Data Exchange (ETDEWEB)
Prykarpatsky, Anatoliy K [Department of Mining Geodesy, AGH University of Science and Technology, Cracow 30059 (Poland); Artemovych, Orest D [Department of Algebra and Topology, Faculty of Mathematics and Informatics of the Vasyl Stefanyk Pre-Carpathian National University, Ivano-Frankivsk (Ukraine); Popowicz, Ziemowit [Institute of Theoretical Physics, University of Wroclaw (Poland); Pavlov, Maxim V, E-mail: pryk.anat@ua.f, E-mail: artemo@usk.pk.edu.p, E-mail: ziemek@ift.uni.wroc.p, E-mail: M.V.Pavlov@lboro.ac.u [Department of Mathematical Physics, P.N. Lebedev Physical Institute, 53 Leninskij Prospekt, Moscow 119991 (Russian Federation)
2010-07-23
A differential-algebraic approach to studying the Lax-type integrability of the generalized Riemann-type hydrodynamic equations at N = 3, 4 is devised. The approach is also applied to studying the Lax-type integrability of the well-known Korteweg-de Vries dynamical system.
Shao, Zhiqiang
2018-04-01
The relativistic full Euler system with generalized Chaplygin proper energy density-pressure relation is studied. The Riemann problem is solved constructively. The delta shock wave arises in the Riemann solutions, provided that the initial data satisfy some certain conditions, although the system is strictly hyperbolic and the first and third characteristic fields are genuinely nonlinear, while the second one is linearly degenerate. There are five kinds of Riemann solutions, in which four only consist of a shock wave and a centered rarefaction wave or two shock waves or two centered rarefaction waves, and a contact discontinuity between the constant states (precisely speaking, the solutions consist in general of three waves), and the other involves delta shocks on which both the rest mass density and the proper energy density simultaneously contain the Dirac delta function. It is quite different from the previous ones on which only one state variable contains the Dirac delta function. The formation mechanism, generalized Rankine-Hugoniot relation and entropy condition are clarified for this type of delta shock wave. Under the generalized Rankine-Hugoniot relation and entropy condition, we establish the existence and uniqueness of solutions involving delta shocks for the Riemann problem.
International Nuclear Information System (INIS)
Prykarpatsky, Anatoliy K; Artemovych, Orest D; Popowicz, Ziemowit; Pavlov, Maxim V
2010-01-01
A differential-algebraic approach to studying the Lax-type integrability of the generalized Riemann-type hydrodynamic equations at N = 3, 4 is devised. The approach is also applied to studying the Lax-type integrability of the well-known Korteweg-de Vries dynamical system.
Kim, Myong-Ha; Ri, Guk-Chol; O, Hyong-Chol
2013-01-01
This paper provides the existence and representation of solution to an initial value problem for the general multi-term linear fractional differential equation with generalized Riemann-Liouville fractional derivatives and constant coefficients by using operational calculus of Mikusinski's type. We prove that the initial value problem has the solution of if and only if some initial values should be zero.
Differential Galois theory through Riemann-Hilbert correspondence an elementary introduction
Sauloy, Jacques
2017-01-01
Differential Galois theory is an important, fast developing area which appears more and more in graduate courses since it mixes fundamental objects from many different areas of mathematics in a stimulating context. For a long time, the dominant approach, usually called Picard-Vessiot Theory, was purely algebraic. This approach has been extensively developed and is well covered in the literature. An alternative approach consists in tagging algebraic objects with transcendental information which enriches the understanding and brings not only new points of view but also new solutions. It is very powerful and can be applied in situations where the Picard-Vessiot approach is not easily extended. This book offers a hands-on transcendental approach to differential Galois theory, based on the Riemann-Hilbert correspondence. Along the way, it provides a smooth, down-to-earth introduction to algebraic geometry, category theory and tannakian duality. Since the book studies only complex analytic linear differential equat...
A boundary-fitted staggered difference method for incompressible flow using Riemann geometry
International Nuclear Information System (INIS)
Koshizuka, Seiichi; Kondo, Shunsuke; Oka, Yoshiaki.
1990-01-01
A boundary-fitted staggered difference method (BFSDM) is investigated for incompressible flow in nuclear plants. BFSDM employs control cells for scalars, staggered location of velocity components, and integrated formulation of div=0. Governing equations are written as coordinate-free forms using Riemann geometry. Flow velocity is represented with contravariant physical components in the present method. Connection terms emerge as source terms in the coordinate-free governing equations. These terms are studied from the viewpoints of physical meaning, numerical stability, and conservative property. Some flows on a round or slant boundary are solved using boundary-fitted curvilinear (BFC) grids and rectangular grids to compare the present method and the rectangular-type (R-type) staggered difference method (SDM). Supercomputing of the present method, including vector processing, is also discussed compared with the R-type method. (author)
Riemann-Liouville integrals of fractional order and extended KP hierarchy
International Nuclear Information System (INIS)
Kamata, Masaru; Nakamula, Atsushi
2002-01-01
An attempt to formulate the extensions of the KP hierarchy by introducing fractional-order pseudo-differential operators is given. In the case of the extension with the half-order pseudo-differential operators, a system analogous to the supersymmetric extensions of the KP hierarchy is obtained. Unlike the supersymmetric extensions, no Grassmannian variable appears in the hierarchy considered here. More general hierarchies constructed by the 1/Nth-order pseudo-differential operators, their integrability and the reduction procedure are also investigated. In addition to finding the new extensions of the KP hierarchy, a brief introduction to the Riemann-Liouville integral is provided to yield a candidate for the fractional-order pseudo-differential operators
A Riemann-Hilbert formulation for the finite temperature Hubbard model
Energy Technology Data Exchange (ETDEWEB)
Cavaglià, Andrea [Dipartimento di Fisica and INFN, Università di Torino,Via P. Giuria 1, 10125 Torino (Italy); Cornagliotto, Martina [Dipartimento di Fisica and INFN, Università di Torino,Via P. Giuria 1, 10125 Torino (Italy); DESY Hamburg, Theory Group,Notkestrasse 85, D-22607 Hamburg (Germany); Mattelliano, Massimo; Tateo, Roberto [Dipartimento di Fisica and INFN, Università di Torino,Via P. Giuria 1, 10125 Torino (Italy)
2015-06-03
Inspired by recent results in the context of AdS/CFT integrability, we reconsider the Thermodynamic Bethe Ansatz equations describing the 1D fermionic Hubbard model at finite temperature. We prove that the infinite set of TBA equations are equivalent to a simple nonlinear Riemann-Hilbert problem for a finite number of unknown functions. The latter can be transformed into a set of three coupled nonlinear integral equations defined over a finite support, which can be easily solved numerically. We discuss the emergence of an exact Bethe Ansatz and the link between the TBA approach and the results by Jüttner, Klümper and Suzuki based on the Quantum Transfer Matrix method. We also comment on the analytic continuation mechanism leading to excited states and on the mirror equations describing the finite-size Hubbard model with twisted boundary conditions.
Zamzamir, Zamzana; Murid, Ali H. M.; Ismail, Munira
2014-06-01
Numerical solution for uniquely solvable exterior Riemann-Hilbert problem on region with corners at offcorner points has been explored by discretizing the related integral equation using Picard iteration method without any modifications to the left-hand side (LHS) and right-hand side (RHS) of the integral equation. Numerical errors for all iterations are converge to the required solution. However, for certain problems, it gives lower accuracy. Hence, this paper presents a new numerical approach for the problem by treating the generalized Neumann kernel at LHS and the function at RHS of the integral equation. Due to the existence of the corner points, Gaussian quadrature is employed which avoids the corner points during numerical integration. Numerical example on a test region is presented to demonstrate the effectiveness of this formulation.
Scattering analysis of asymmetric metamaterial resonators by the Riemann-Hilbert approach
DEFF Research Database (Denmark)
Kaminski, Piotr Marek; Ziolkowski, Richard W.; Arslanagic, Samel
2016-01-01
This work presents an analytical treatment of an asymmetric metamaterial-based resonator excited by an electric line source, and explores its beam shaping capabilities. The resonator consists of two concentric cylindrical material layers covered with an infinitely thin conducting shell with an ap......This work presents an analytical treatment of an asymmetric metamaterial-based resonator excited by an electric line source, and explores its beam shaping capabilities. The resonator consists of two concentric cylindrical material layers covered with an infinitely thin conducting shell...... with an aperture. Exact analytical solution of the problem is derived; it is based on the n-series approach which is casted into the equivalent Riemann-Hilbert problem. The examined configuration leads to large enhancements of the radiated field and to steerable Huygens-like directivity patterns. Particularly...
Riemann surfaces and algebraic curves a first course in Hurwitz theory
Cavalieri, Renzo
2016-01-01
Hurwitz theory, the study of analytic functions among Riemann surfaces, is a classical field and active research area in algebraic geometry. The subject's interplay between algebra, geometry, topology and analysis is a beautiful example of the interconnectedness of mathematics. This book introduces students to this increasingly important field, covering key topics such as manifolds, monodromy representations and the Hurwitz potential. Designed for undergraduate study, this classroom-tested text includes over 100 exercises to provide motivation for the reader. Also included are short essays by guest writers on how they use Hurwitz theory in their work, which ranges from string theory to non-Archimedean geometry. Whether used in a course or as a self-contained reference for graduate students, this book will provide an exciting glimpse at mathematics beyond the standard university classes.
Eigenfunctions and Eigenvalues for a Scalar Riemann-Hilbert Problem Associated to Inverse Scattering
Pelinovsky, Dmitry E.; Sulem, Catherine
A complete set of eigenfunctions is introduced within the Riemann-Hilbert formalism for spectral problems associated to some solvable nonlinear evolution equations. In particular, we consider the time-independent and time-dependent Schrödinger problems which are related to the KdV and KPI equations possessing solitons and lumps, respectively. Non-standard scalar products, orthogonality and completeness relations are derived for these problems. The complete set of eigenfunctions is used for perturbation theory and bifurcation analysis of eigenvalues supported by the potentials under perturbations. We classify two different types of bifurcations of new eigenvalues and analyze their characteristic features. One type corresponds to thresholdless generation of solitons in the KdV equation, while the other predicts a threshold for generation of lumps in the KPI equation.
Lapidus, Michel L
2015-08-06
This research expository article not only contains a survey of earlier work but also contains a main new result, which we first describe. Given c≥0, the spectral operator [Formula: see text] can be thought of intuitively as the operator which sends the geometry onto the spectrum of a fractal string of dimension not exceeding c. Rigorously, it turns out to coincide with a suitable quantization of the Riemann zeta function ζ=ζ(s): a=ζ(∂), where ∂=∂(c) is the infinitesimal shift of the real line acting on the weighted Hilbert space [Formula: see text]. In this paper, we establish a new asymmetric criterion for the Riemann hypothesis (RH), expressed in terms of the invertibility of the spectral operator for all values of the dimension parameter [Formula: see text] (i.e. for all c in the left half of the critical interval (0,1)). This corresponds (conditionally) to a mathematical (and perhaps also, physical) 'phase transition' occurring in the midfractal case when [Formula: see text]. Both the universality and the non-universality of ζ=ζ(s) in the right (resp., left) critical strip [Formula: see text] (resp., [Formula: see text]) play a key role in this context. These new results are presented here. We also briefly discuss earlier joint work on the complex dimensions of fractal strings, and we survey earlier related work of the author with Maier and with Herichi, respectively, in which were established symmetric criteria for the RH, expressed, respectively, in terms of a family of natural inverse spectral problems for fractal strings of Minkowski dimension D∈(0,1), with [Formula: see text], and of the quasi-invertibility of the family of spectral operators [Formula: see text] (with [Formula: see text]). © 2015 The Author(s) Published by the Royal Society. All rights reserved.
Implicit approximate Riemann solver for two fluid two phase flow models
International Nuclear Information System (INIS)
Raymond, P.; Toumi, I.; Kumbaro, A.
1993-01-01
This paper is devoted to the description of new numerical methods developed for the numerical treatment of two phase flow models with two velocity fields which are now widely used in nuclear engineering for design or safety calculations. These methods are finite volumes numerical methods and are based on the use of Approximate Riemann Solver's concepts in order to define convective flux versus mean cell quantities. The first part of the communication will describe the numerical method for a three dimensional drift flux model and the extensions which were performed to make the numerical scheme implicit and to have fast running calculations of steady states. Such a scheme is now implemented in the FLICA-4 computer code devoted to 3-D steady state and transient core computations. We will present results obtained for a steady state flow with rod bow effect evaluation and for a Steam Line Break calculation were the 3-D core thermal computation was coupled with a 3-D kinetic calculation and a thermal-hydraulic transient calculation for the four loops of a Pressurized Water Reactor. The second part of the paper will detail the development of an equivalent numerical method based on an approximate Riemann Solver for a two fluid model with two momentum balance equations for the liquid and the gas phases. The main difficulty for these models is due to the existence of differential modelling terms such as added mass effects or interfacial pressure terms which make hyperbolic the model. These terms does not permit to write the balance equations system in a conservative form, and the classical theory for discontinuity propagation for non-linear systems cannot be applied. Meanwhile, the use of non-conservative products theory allows the study of discontinuity propagation for a non conservative model and this will permit the construction of a numerical scheme for two fluid two phase flow model. These different points will be detailed in that section which will be illustrated by
Saka, Takashi
2016-05-01
The dynamical theory for perfect crystals in the Laue case was reformulated using the Riemann surface, as used in complex analysis. In the two-beam approximation, each branch of the dispersion surface is specified by one sheet of the Riemann surface. The characteristic features of the dispersion surface are analytically revealed using four parameters, which are the real and imaginary parts of two quantities specifying the degree of departure from the exact Bragg condition and the reflection strength. By representing these parameters on complex planes, these characteristics can be graphically depicted on the Riemann surface. In the conventional case, the absorption is small and the real part of the reflection strength is large, so the formulation is the same as the traditional analysis. However, when the real part of the reflection strength is small or zero, the two branches of the dispersion surface cross, and the dispersion relationship becomes similar to that of the Bragg case. This is because the geometrical relationships among the parameters are similar in both cases. The present analytical method is generally applicable, irrespective of the magnitudes of the parameters. Furthermore, the present method analytically revealed many characteristic features of the dispersion surface and will be quite instructive for further numerical calculations of rocking curves.
Cylinder renormalization for Siegel disks and a constructive Measurable Riemann Mapping Theorem
Gaydashev, D G
2006-01-01
The boundary of the Siegel disk of a quadratic polynomial with an irrationally indifferent fixed point with the golden mean rotation number has been observed to be self-similar. The geometry of this self-similarity is universal for a large class of holomorphic maps. A renormalization explanation of this universality has been proposed in the literature. However, one of the ingredients of this explanation, the hyperbolicity of renormalization, has not been proved yet. The present work considers a cylinder renormalization - a novel type of renormalization for holomorphic maps with a Siegel disk which is better suited for a hyperbolicity proof. A key element of a cylinder renormalization of a holomorphic map is a conformal isomorphism of a dynamical quotient of a subset of $\\field{C}$ to a bi-infinite cylinder $\\field{C} / \\field{Z}$. A construction of this conformal isomorphism is an implicit procedure which can be performed using the Measurable Riemann Mapping Theorem. We present a constructive proof of the Mea...
Jumarie, Guy
2013-04-01
By using fractional differences, one recently proposed an alternative to the formulation of fractional differential calculus, of which the main characteristics is a new fractional Taylor series and its companion Rolle's formula which apply to non-differentiable functions. The key is that now we have at hand a differential increment of fractional order which can be manipulated exactly like in the standard Leibniz differential calculus. Briefly the fractional derivative is the quotient of fractional increments. It has been proposed that this calculus can be used to construct a differential geometry on manifold of fractional order. The present paper, on the one hand, refines the framework, and on the other hand, contributes some new results related to arc length of fractional curves, area on fractional differentiable manifold, covariant fractal derivative, Riemann-Christoffel tensor of fractional order, fractional differential equations of fractional geodesic, strip modeling of fractal space time and its relation with Lorentz transformation. The relation with Nottale's fractal space-time theory then appears in quite a natural way.
Approximate Riemann solvers and flux vector splitting schemes for two-phase flow
International Nuclear Information System (INIS)
Toumi, I.; Kumbaro, A.; Paillere, H.
1999-01-01
These course notes, presented at the 30. Von Karman Institute Lecture Series in Computational Fluid Dynamics, give a detailed and through review of upwind differencing methods for two-phase flow models. After recalling some fundamental aspects of two-phase flow modelling, from mixture model to two-fluid models, the mathematical properties of the general 6-equation model are analysed by examining the Eigen-structure of the system, and deriving conditions under which the model can be made hyperbolic. The following chapters are devoted to extensions of state-of-the-art upwind differencing schemes such as Roe's Approximate Riemann Solver or the Characteristic Flux Splitting method to two-phase flow. Non-trivial steps in the construction of such solvers include the linearization, the treatment of non-conservative terms and the construction of a Roe-type matrix on which the numerical dissipation of the schemes is based. Extension of the 1-D models to multi-dimensions in an unstructured finite volume formulation is also described; Finally, numerical results for a variety of test-cases are shown to illustrate the accuracy and robustness of the methods. (authors)
A geometric construction of the Riemann scalar curvature in Regge calculus
McDonald, Jonathan R.; Miller, Warner A.
2008-10-01
The Riemann scalar curvature plays a central role in Einstein's geometric theory of gravity. We describe a new geometric construction of this scalar curvature invariant at an event (vertex) in a discrete spacetime geometry. This allows one to constructively measure the scalar curvature using only clocks and photons. Given recent interest in discrete pre-geometric models of quantum gravity, we believe is it ever so important to reconstruct the curvature scalar with respect to a finite number of communicating observers. This derivation makes use of a new fundamental lattice cell built from elements inherited from both the original simplicial (Delaunay) spacetime and its circumcentric dual (Voronoi) lattice. The orthogonality properties between these two lattices yield an expression for the vertex-based scalar curvature which is strikingly similar to the corresponding hinge-based expression in Regge calculus (deficit angle per unit Voronoi dual area). In particular, we show that the scalar curvature is simply a vertex-based weighted average of deficits per weighted average of dual areas.
International Nuclear Information System (INIS)
Loubere, Raphael; Maire, Pierre-Henri; Vachal, Pavel
2013-01-01
The aim of the present work is the 3D extension of a general formalism to derive a staggered discretization for Lagrangian hydrodynamics on unstructured grids. The classical compatible discretization is used; namely, momentum equation is discretized using the fundamental concept of subcell forces. Specific internal energy equation is obtained using total energy conservation. The subcell force is derived by invoking the Galilean invariance and thermodynamic consistency. A general form of the subcell force is provided so that a cell entropy inequality is satisfied. The subcell force consists of a classical pressure term plus a tensorial viscous contribution proportional to the difference between the node velocity and the cell-centered velocity. This cell-centered velocity is an extra degree of freedom solved with a cell-centered approximate Riemann solver. The second law of thermodynamics is satisfied by construction of the local positive definite subcell tensor involved in the viscous term. A particular expression of this tensor is proposed. A more accurate extension of this discretization both in time and space is also provided using a piecewise linear reconstruction of the velocity field and a predictor-corrector time discretization. Numerical tests are presented in order to assess the efficiency of this approach in 3D. Sanity checks show that the 3D extension of the 2D approach reproduces 1D and 2D results. Finally, 3D problems such as Sedov, Noh, and Saltzman are simulated. (authors)
A geometric construction of the Riemann scalar curvature in Regge calculus
International Nuclear Information System (INIS)
McDonald, Jonathan R; Miller, Warner A
2008-01-01
The Riemann scalar curvature plays a central role in Einstein's geometric theory of gravity. We describe a new geometric construction of this scalar curvature invariant at an event (vertex) in a discrete spacetime geometry. This allows one to constructively measure the scalar curvature using only clocks and photons. Given recent interest in discrete pre-geometric models of quantum gravity, we believe is it ever so important to reconstruct the curvature scalar with respect to a finite number of communicating observers. This derivation makes use of a new fundamental lattice cell built from elements inherited from both the original simplicial (Delaunay) spacetime and its circumcentric dual (Voronoi) lattice. The orthogonality properties between these two lattices yield an expression for the vertex-based scalar curvature which is strikingly similar to the corresponding hinge-based expression in Regge calculus (deficit angle per unit Voronoi dual area). In particular, we show that the scalar curvature is simply a vertex-based weighted average of deficits per weighted average of dual areas
On membrane interactions and a three-dimensional analog of Riemann surfaces
Energy Technology Data Exchange (ETDEWEB)
Kovacs, Stefano [Dublin Institute for Advanced Studies, 10 Burlington Road, Dublin 4 (Ireland); ICTP South American Institute for Fundamental Research, IFT-UNESP,São Paulo, SP 01440-070 (Brazil); Sato, Yuki [National Institute for Theoretical Physics, School of Physics and Mandelstam Institute for Theoretical Physics, University of the Witwartersrand,Wits 2050 (South Africa); Shimada, Hidehiko [Okayama Institute for Quantum Physics,Okayama (Japan)
2016-02-08
Membranes in M-theory are expected to interact via splitting and joining processes. We study these effects in the pp-wave matrix model, in which they are associated with transitions between states in sectors built on vacua with different numbers of membranes. Transition amplitudes between such states receive contributions from BPS instanton configurations interpolating between the different vacua. Various properties of the moduli space of BPS instantons are known, but there are very few known examples of explicit solutions. We present a new approach to the construction of instanton solutions interpolating between states containing arbitrary numbers of membranes, based on a continuum approximation valid for matrices of large size. The proposed scheme uses functions on a two-dimensional space to approximate matrices and it relies on the same ideas behind the matrix regularisation of membrane degrees of freedom in M-theory. We show that the BPS instanton equations have a continuum counterpart which can be mapped to the three-dimensional Laplace equation through a sequence of changes of variables. A description of configurations corresponding to membrane splitting/joining processes can be given in terms of solutions to the Laplace equation in a three-dimensional analog of a Riemann surface, consisting of multiple copies of ℝ{sup 3} connected via a generalisation of branch cuts. We discuss various general features of our proposal and we also present explicit analytic solutions.
On the properties of torsions in Riemann-Cartan space-times
International Nuclear Information System (INIS)
Baker, W.M.; Atkins, W.K.; Davis, W.R.
1978-01-01
This paper is the first paper in a series of three papers dealing with the physical properties of torsions in Riemann-Cartan space-times (U 4 ). Paper one deals with the particular types of torsion that can be associated with the U 4 reinterpretation of a special class of null electromagnetic solutions of the standard form of Einstein's equations. In particular, for plane null electromagnetic solutions, three types of torsion solutions are associated with this type of reinterpretation. Two of these solutions, the trivector and semi-symmetric torsions, although rather special, serve as examples of what could be done to find the associated torsions in terms of simple requirements on identities in U 4 . The third class is obtained by relating the contorsion to the Lanczos ''spin'' tensor. Paper two, dealing with gravitational radiation, provides the proper background relating to the physical significance of the Lanczos tensor. This series of papers is primarily concerned with the question of the possible physical role of all types of torsion, compatible with an extension or an U 4 reinterpretation of Einstein's theory, consistent with the broadest possible interpretation of the present form of the Einstein-Cartan-Sciama-Kibble theory. However, in paper three some consideration will be given on theories with simpler metrical generalizations of U 4 and the related types of torsion. We emphasize that the content of paper one and two should be viewed mainly as special formal results that introduce the more general considerations of paper three
On membrane interactions and a three-dimensional analog of Riemann surfaces
International Nuclear Information System (INIS)
Kovacs, Stefano; Sato, Yuki; Shimada, Hidehiko
2016-01-01
Membranes in M-theory are expected to interact via splitting and joining processes. We study these effects in the pp-wave matrix model, in which they are associated with transitions between states in sectors built on vacua with different numbers of membranes. Transition amplitudes between such states receive contributions from BPS instanton configurations interpolating between the different vacua. Various properties of the moduli space of BPS instantons are known, but there are very few known examples of explicit solutions. We present a new approach to the construction of instanton solutions interpolating between states containing arbitrary numbers of membranes, based on a continuum approximation valid for matrices of large size. The proposed scheme uses functions on a two-dimensional space to approximate matrices and it relies on the same ideas behind the matrix regularisation of membrane degrees of freedom in M-theory. We show that the BPS instanton equations have a continuum counterpart which can be mapped to the three-dimensional Laplace equation through a sequence of changes of variables. A description of configurations corresponding to membrane splitting/joining processes can be given in terms of solutions to the Laplace equation in a three-dimensional analog of a Riemann surface, consisting of multiple copies of ℝ"3 connected via a generalisation of branch cuts. We discuss various general features of our proposal and we also present explicit analytic solutions.
Multi-Regge kinematics and the moduli space of Riemann spheres with marked points
Energy Technology Data Exchange (ETDEWEB)
Duca, Vittorio Del [Institute for Theoretical Physics, ETH Zürich,Hönggerberg, 8093 Zürich (Switzerland); Druc, Stefan; Drummond, James [School of Physics & Astronomy, University of Southampton,Highfield, Southampton, SO17 1BJ (United Kingdom); Duhr, Claude [Theoretical Physics Department, CERN,Route de Meyrin, CH-1211 Geneva 23 (Switzerland); Center for Cosmology, Particle Physics and Phenomenology (CP3),Université catholique de Louvain,Chemin du Cyclotron 2, 1348 Louvain-La-Neuve (Belgium); Dulat, Falko [SLAC National Accelerator Laboratory, Stanford University,Stanford, CA 94309 (United States); Marzucca, Robin [Center for Cosmology, Particle Physics and Phenomenology (CP3),Université catholique de Louvain,Chemin du Cyclotron 2, 1348 Louvain-La-Neuve (Belgium); Papathanasiou, Georgios [SLAC National Accelerator Laboratory, Stanford University,Stanford, CA 94309 (United States); Verbeek, Bram [Center for Cosmology, Particle Physics and Phenomenology (CP3),Université catholique de Louvain,Chemin du Cyclotron 2, 1348 Louvain-La-Neuve (Belgium)
2016-08-25
We show that scattering amplitudes in planar N=4 Super Yang-Mills in multi-Regge kinematics can naturally be expressed in terms of single-valued iterated integrals on the moduli space of Riemann spheres with marked points. As a consequence, scattering amplitudes in this limit can be expressed as convolutions that can easily be computed using Stokes’ theorem. We apply this framework to MHV amplitudes to leading-logarithmic accuracy (LLA), and we prove that at L loops all MHV amplitudes are determined by amplitudes with up to L+4 external legs. We also investigate non-MHV amplitudes, and we show that they can be obtained by convoluting the MHV results with a certain helicity flip kernel. We classify all leading singularities that appear at LLA in the Regge limit for arbitrary helicity configurations and any number of external legs. Finally, we use our new framework to obtain explicit analytic results at LLA for all MHV amplitudes up to five loops and all non-MHV amplitudes with up to eight external legs and four loops.
AdS5 solutions from M5-branes on Riemann surface and D6-branes sources
Energy Technology Data Exchange (ETDEWEB)
Bah, Ibrahima [Department of Physics and Astronomy, University of Southern California,Los Angeles, CA 90089 (United States); Institut de Physique Théorique, CEA/Saclay,91191 Gif-sur-Yvette (France)
2015-09-24
We describe the gravity duals of four-dimensional N=1 superconformal field theories obtained by wrapping M5-branes on a punctured Riemann surface. The internal geometry, normal to the AdS{sub 5} factor, generically preserves two U(1)s, with generators (J{sup +},J{sup −}), that are fibered over the Riemann surface. The metric is governed by a single potential that satisfies a version of the Monge-Ampère equation. The spectrum of N=1 punctures is given by the set of supersymmetric sources of the potential that are localized on the Riemann surface and lead to regular metrics near a puncture. We use this system to study a class of punctures where the geometry near the sources corresponds to M-theory description of D6-branes. These carry a natural (p,q) label associated to the circle dual to the killing vector pJ{sup +}+qJ{sup −} which shrinks near the source. In the generic case the world volume of the D6-branes is AdS{sub 5}×S{sup 2} and they locally preserve N=2 supersymmetry. When p=−q, the shrinking circle is dual to a flavor U(1). The metric in this case is non-degenerate only when there are co-dimension one sources obtained by smearing M5-branes that wrap the AdS{sub 5} factor and the circle dual the superconformal R-symmetry. The D6-branes are extended along the AdS{sub 5} and on cups that end on the co-dimension one branes. In the special case when the shrinking circle is dual to the R-symmetry, the D6-branes are extended along the AdS{sub 5} and wrap an auxiliary Riemann surface with an arbitrary genus. When the Riemann surface is compact with constant curvature, the system is governed by a Monge-Ampère equation.
Võimsad taimed / Rachel Hartigan Shea
Hartigan Shea, Rachel
2016-01-01
Füüsik Eleni Stavrinidou töörühm pani lõigatud roosi varreotsa lahjendatud polümeerlahusesse, moodustades ksüleemis elektrijuhi. Selline tehnoloogia võimaldaks toota andureid, mis suudavad analüüsida ja muuta taime füsioloogiat raku tasandil, toota fotosünteesiga elektrit
Sotsiaalmeedia avalikus sektoris / Rachel Branten
Branten, Rachel
2016-01-01
Artikli aluseks on autori bakalaureusetöö, milles on analüüs tehtud majandus- ja kommunikatsiooniministeeriumi ning selle allasutuste 2015. aasta Facebooki postituste näitel. I. Mergeli esitatud teoreetilise raamistiku rakendamisest avaliku sektori sotsiaalmeedia kasutuse mõõtmisel ja analüüsimisel
Rachel's Story: A Transpersonal Experience.
Holden, Janice Miner
2000-01-01
This article presents a case study in which a client's transpersonal/religious/spiritual experience facilitated the achievement of her counseling goal. Through the paranormal experience, she resolved several of her conflicts, including a new appreciation of the church from which she had become estranged. (Author)
Rachel the Jewess in Copenhagen
DEFF Research Database (Denmark)
Hesselager, Jens
2012-01-01
are considered in relation to the local critical discourse on operatic performances at the Royal Theatre in Copenhagen in general – a context which, in 1842, involved the phenomenon of a competing and quite successful Italian opera company at the nearby Court Theatre. This situation generated a general trend...
Adaptive spacetime method using Riemann jump conditions for coupled atomistic-continuum dynamics
International Nuclear Information System (INIS)
Kraczek, B.; Miller, S.T.; Haber, R.B.; Johnson, D.D.
2010-01-01
We combine the Spacetime Discontinuous Galerkin (SDG) method for elastodynamics with the mathematically consistent Atomistic Discontinuous Galerkin (ADG) method in a new scheme that concurrently couples continuum and atomistic models of dynamic response in solids. The formulation couples non-overlapping continuum and atomistic models across sharp interfaces by weakly enforcing jump conditions, for both momentum balance and kinematic compatibility, using Riemann values to preserve the characteristic structure of the underlying hyperbolic system. Momentum balances to within machine-precision accuracy over every element, on each atom, and over the coupled system, with small, controllable energy dissipation in the continuum region that ensures numerical stability. When implemented on suitable unstructured spacetime grids, the continuum SDG model offers linear computational complexity in the number of elements and powerful adaptive analysis capabilities that readily bridge between atomic and continuum scales in both space and time. A special trace operator for the atomic velocities and an associated atomistic traction field enter the jump conditions at the coupling interface. The trace operator depends on parameters that specify, at the scale of the atomic spacing, the position of the coupling interface relative to the atoms. In a key finding, we demonstrate that optimizing these parameters suppresses spurious reflections at the coupling interface without the use of non-physical damping or special boundary conditions. We formulate the implicit SDG-ADG coupling scheme in up to three spatial dimensions, and describe an efficient iterative solution scheme that outperforms common explicit schemes, such as the Velocity Verlet integrator. Numerical examples, in 1dxtime and employing both linear and nonlinear potentials, demonstrate the performance of the SDG-ADG method and show how adaptive spacetime meshing reconciles disparate time steps and resolves atomic-scale signals in
Energy Technology Data Exchange (ETDEWEB)
Beccantini, A
2001-07-01
This thesis represents a contribution to the development of upwind splitting schemes for the Euler equations for ideal gaseous mixtures and their investigation in computing multidimensional flows in irregular geometries. In the preliminary part we develop and investigate the parameterization of the shock and rarefaction curves in the phase space. Then, we apply them to perform some field-by-field decompositions of the Riemann problem: the entropy-respecting one, the one which supposes that genuinely-non-linear (GNL) waves are both shocks (shock-shock one) and the one which supposes that GNL waves are both rarefactions (rarefaction-rarefaction one). We emphasize that their analysis is fundamental in Riemann solvers developing: the simpler the field-by-field decomposition, the simpler the Riemann solver based on it. As the specific heat capacities of the gases depend on the temperature, the shock-shock field-by-field decomposition is the easiest to perform. Then, in the second part of the thesis, we develop an upwind splitting scheme based on such decomposition. Afterwards, we investigate its robustness, precision and CPU-time consumption, with respect to some of the most popular upwind splitting schemes for polytropic/non-polytropic ideal gases. 1-D test-cases show that this scheme is both precise (exact capturing of stationary shock and stationary contact) and robust in dealing with strong shock and rarefaction waves. Multidimensional test-cases show that it suffers from some of the typical deficiencies which affect the upwind splitting schemes capable of exact capturing stationary contact discontinuities i.e the developing of non-physical instabilities in computing strong shock waves. In the final part, we use the high-order multidimensional solver here developed to compute fully-developed detonation flows. (author)
Directory of Open Access Journals (Sweden)
Jolanta Golenia
2010-01-01
Full Text Available Short-wave perturbations in a relaxing medium, governed by a special reduction of the Ostrovsky evolution equation, and later derived by Whitham, are studied using the gradient-holonomic integrability algorithm. The bi-Hamiltonicity and complete integrability of the corresponding dynamical system is stated and an infinite hierarchy of commuting to each other conservation laws of dispersive type are found. The well defined regularization of the model is constructed and its Lax type integrability is discussed. A generalized hydrodynamical Riemann type system is considered, infinite hierarchies of conservation laws, related compatible Poisson structures and a Lax type representation for the special case N=3 are constructed.
Zeros da função zeta de Riemann e o teorema dos números primos
Oliveira, Willian Diego [UNESP
2013-01-01
We studied various properties of the Riemann’s zeta function. Three proofs of the Prime Number Theorem were provides. Classical results on zero-free region of the zeta function, as well as their relation to the error term in the Prime Number Theorem, were studied in details Estudamos várias propriedades da função zeta de Riemann. Três provas do Teorema dos Números Primos foram fornecidas. Resultados clássicos sobre regiões livres de zeros da função zeta, bem como sua relação com o termo do...
International Nuclear Information System (INIS)
Le Mehaute, Alain; El Kaabouchi, Abdelaziz; Nivanen, Laurent
2008-01-01
Advances in fractional analysis suggest a new way for the physics understanding of Riemann's conjecture. It asserts that, if s is a complex number, the non trivial zeros of zeta function 1/(ζ(s)) =Σ n=1 ∞ (μ(n))/(n s ) in the gap [0, 1], is characterized by s=1/2 (1+2iθ). This conjecture can be understood as a consequence of 1/2-order fractional differential characteristics of automorph dynamics upon opened punctuated torus with an angle at infinity equal to π/4. This physical interpretation suggests new opportunities for revisiting the cryptographic methodologies
Adamowicz, S.C.; Roman, C.T.
2002-01-01
This study evaluates the response of three salt marshes, associated with the Rachel Carson National Wildlife Refuge (Maine), to the practice of ditch plugging. Drainage ditches, originally dug to drain the marsh for mosquito control or to facilitate salt hay farming, are plugged with marsh peat in an effort to impound water upstream of the plug, raise water table levels in the marsh, and increase surface water habitat. At two study sites, Moody Marsh and Granite Point Road Marsh, ditch plugs were installed in spring 2000. Monitoring of hydrology, vegetation, nekton and bird utilization, and marsh development processes was conducted in 1999, before ditch plugging, and then in 2000 and 2001 (all parameters except nekton), after ditch plugging. Each study site had a control marsh that was monitored simultaneously with the plugged marsh, and thus, we employed a BACI study design (before, after, control, impact). A third site, Marshall Point Road Marsh, was plugged in 1998. Monitoring of the plugged and control sites was conducted in 1999 and 2000, with limited monitoring in 2001, thus there was no ?before? plug monitoring. With ditch plugging, water table levels increased toward the marsh surface and the areal extent of standing water increased. Responding to a wetter substrate, a vegetation change from high marsh species (e.g., Spartina patens) to those more tolerant of flooded conditions (e.g., Spartina alterniflora) was noted at two of the three ditch plugged sites. Initial response of the nekton community (fishes and decapod crustaceans) was evaluated by monitoring utilization of salt marsh pools using a 1m2 enclosure trap. In general, nekton species richness, density, and community structure remained unchanged following ditch plugging at the Moody and Granite Point sites. At Marshall Point, species richness and density (number of individuals per m2) were significantly greater in the experimental plugged marsh than the control marsh (<2% of the control marsh was
Bui-Thanh, T.; Girolami, M.
2014-11-01
We consider the Riemann manifold Hamiltonian Monte Carlo (RMHMC) method for solving statistical inverse problems governed by partial differential equations (PDEs). The Bayesian framework is employed to cast the inverse problem into the task of statistical inference whose solution is the posterior distribution in infinite dimensional parameter space conditional upon observation data and Gaussian prior measure. We discretize both the likelihood and the prior using the H1-conforming finite element method together with a matrix transfer technique. The power of the RMHMC method is that it exploits the geometric structure induced by the PDE constraints of the underlying inverse problem. Consequently, each RMHMC posterior sample is almost uncorrelated/independent from the others providing statistically efficient Markov chain simulation. However this statistical efficiency comes at a computational cost. This motivates us to consider computationally more efficient strategies for RMHMC. At the heart of our construction is the fact that for Gaussian error structures the Fisher information matrix coincides with the Gauss-Newton Hessian. We exploit this fact in considering a computationally simplified RMHMC method combining state-of-the-art adjoint techniques and the superiority of the RMHMC method. Specifically, we first form the Gauss-Newton Hessian at the maximum a posteriori point and then use it as a fixed constant metric tensor throughout RMHMC simulation. This eliminates the need for the computationally costly differential geometric Christoffel symbols, which in turn greatly reduces computational effort at a corresponding loss of sampling efficiency. We further reduce the cost of forming the Fisher information matrix by using a low rank approximation via a randomized singular value decomposition technique. This is efficient since a small number of Hessian-vector products are required. The Hessian-vector product in turn requires only two extra PDE solves using the adjoint
International Nuclear Information System (INIS)
Minkowski, P.
1986-01-01
The metric and contorsion tensors are constructed which yield a combined Riemann curvature tensor of the form Rsup(+-)sub(μνsigmatau)=(1/2a 2 )(gsub(μsigma)gsub(νtau) - gsub(μtau)gsub(νsigma)+-√g epsilonsub(μνsigmatau)). The metric with euclidean signature (++++) describes a sphere S 4 with radius a, i.e. admits the isometry group O5. For selfdual (antiselfdual) curvature tensor the contorsion tensor is given by the antiselfdual (selfdual) instanton configuration with respect to the spin gauge group SU2sub(R) (SU2sub(L)). The selfdual (antiselfdual) Riemann tensor admits two covariantly constant right-handed (left-handed) spin 1/2 fermion zero modes, one J=1/2 and one J=3/2 right-handed (left-handed) multiplet corresponding to L=1, transforming as a pseudoreal representation of O4 (SU2sub(R(L))). The hermitean Dirac equation retains only the two constant chiral modes. (orig.)
Pioline, Boris
2016-01-01
The Kawazumi-Zhang invariant $\\varphi$ for compact genus-two Riemann surfaces was recently shown to be a eigenmode of the Laplacian on the Siegel upper half-plane, away from the separating degeneration divisor. Using this fact and the known behavior of $\\varphi$ in the non-separating degeneration limit, it is shown that $\\varphi$ is equal to the Theta lift of the unique (up to normalization) weak Jacobi form of weight $-2$. This identification provides the complete Fourier-Jacobi expansion of $\\varphi$ near the non-separating node, gives full control on the asymptotics of $\\varphi$ in the various degeneration limits, and provides a efficient numerical procedure to evaluate $\\varphi$ to arbitrary accuracy. It also reveals a mock-type holomorphic Siegel modular form of weight $-2$ underlying $\\varphi$. From the general relation between the Faltings invariant, the Kawazumi-Zhang invariant and the discriminant for hyperelliptic Riemann surfaces, a Theta lift representation for the Faltings invariant in genus two ...
La notion husserlienne de multiplicité : au-delà de Cantor et Riemann
Directory of Open Access Journals (Sweden)
Carlo Ierna
2012-04-01
Full Text Available En raison du rôle changeant qu’il joue dans les différents ouvrages de Husserl, le concept de Mannigfaltigkeit afait l’objet de nombreuses interprétations. La présence de ce terme a notamment induit en erreur plusieurs commentateurs, qui ont cru en déterminer l’origine dans les années de Halle, à l’époque où Husserl, ami et collègue de Cantor, rédigeait la Philosophie de l’arithmétique. Mais force est de constater qu’à cette époque Husserl s’était déjà ouvertement éloigné de la définition cantorienne de Mannigfaltigkeit en s’approchant plutôt de Riemann, comme le montrent les nombreuses études et leçons qui lui sont consacrées. La Mannigfaltigkeitslehre de Husserl semble donc plus proche de la topologie que de la théorie des ensembles de Cantor. Ainsi, dans les Prolégomènes, Husserl introduit l’idée d’une Mannigfaltigkeitslehre pure en tant qu’entreprise méta-théorique dont le but est d’étudier les relations entre théories, à savoir la manière par laquelle une théorie est dérivée ou fondée à partir d’une autre. Dès lors, lorsque Husserl affirme que le meilleur exemple d’une telle théorie pure des multiplicités se trouve dans les mathématiques, cela risque donc de prêter à confusion. En effet, la théorie pure des théories ne saurait être simplement identifiée aux mathématiques qui relèvent de la topologie, mais considérée en tant que mathesis universalis. Bien qu’une telle position ne fût sans doute pas entièrement claire en 1900-01, Husserl ne tardera pas à relier explicitement théorie des multiplicités et mathesis universalis.En ce sens, la mathesis universalis, théorie des théories en général, est une discipline formelle, apriori et analytique qui a pour but l’analyse des catégories sémantiques suprêmes et des catégories d’objets qui leur sont corrélées. Dans cet article j’essayerai de comprendre le développement de la notion de
Directory of Open Access Journals (Sweden)
Regma Maria Santos
2013-07-01
Full Text Available Este texto tem como objetivo apresentar a possibilidade de utilizar, no ensino de História, a crônica escrita por Rachel de Queiroz em jornais e revistas da primeira metade do século XX. Apresentamos antes uma breve biografia da autora, enfocando o contexto de sua produção, e depois realizamos uma breve análise da crônica selecionada, sinalizando oportunidades para trabalhar com os estudantes. Este documento oferece uma leitura pessoal sobre certos temas e também uma percepção histórica mais ampla e mais crítica do mundo.
Balsara, Dinshaw S.; Dumbser, Michael
2015-10-01
Several advances have been reported in the recent literature on divergence-free finite volume schemes for Magnetohydrodynamics (MHD). Almost all of these advances are restricted to structured meshes. To retain full geometric versatility, however, it is also very important to make analogous advances in divergence-free schemes for MHD on unstructured meshes. Such schemes utilize a staggered Yee-type mesh, where all hydrodynamic quantities (mass, momentum and energy density) are cell-centered, while the magnetic fields are face-centered and the electric fields, which are so useful for the time update of the magnetic field, are centered at the edges. Three important advances are brought together in this paper in order to make it possible to have high order accurate finite volume schemes for the MHD equations on unstructured meshes. First, it is shown that a divergence-free WENO reconstruction of the magnetic field can be developed for unstructured meshes in two and three space dimensions using a classical cell-centered WENO algorithm, without the need to do a WENO reconstruction for the magnetic field on the faces. This is achieved via a novel constrained L2-projection operator that is used in each time step as a postprocessor of the cell-centered WENO reconstruction so that the magnetic field becomes locally and globally divergence free. Second, it is shown that recently-developed genuinely multidimensional Riemann solvers (called MuSIC Riemann solvers) can be used on unstructured meshes to obtain a multidimensionally upwinded representation of the electric field at each edge. Third, the above two innovations work well together with a high order accurate one-step ADER time stepping strategy, which requires the divergence-free nonlinear WENO reconstruction procedure to be carried out only once per time step. The resulting divergence-free ADER-WENO schemes with MuSIC Riemann solvers give us an efficient and easily-implemented strategy for divergence-free MHD on
Carraro, F.; Valiani, A.; Caleffi, V.
2018-03-01
Within the framework of the de Saint Venant equations coupled with the Exner equation for morphodynamic evolution, this work presents a new efficient implementation of the Dumbser-Osher-Toro (DOT) scheme for non-conservative problems. The DOT path-conservative scheme is a robust upwind method based on a complete Riemann solver, but it has the drawback of requiring expensive numerical computations. Indeed, to compute the non-linear time evolution in each time step, the DOT scheme requires numerical computation of the flux matrix eigenstructure (the totality of eigenvalues and eigenvectors) several times at each cell edge. In this work, an analytical and compact formulation of the eigenstructure for the de Saint Venant-Exner (dSVE) model is introduced and tested in terms of numerical efficiency and stability. Using the original DOT and PRICE-C (a very efficient FORCE-type method) as reference methods, we present a convergence analysis (error against CPU time) to study the performance of the DOT method with our new analytical implementation of eigenstructure calculations (A-DOT). In particular, the numerical performance of the three methods is tested in three test cases: a movable bed Riemann problem with analytical solution; a problem with smooth analytical solution; a test in which the water flow is characterised by subcritical and supercritical regions. For a given target error, the A-DOT method is always the most efficient choice. Finally, two experimental data sets and different transport formulae are considered to test the A-DOT model in more practical case studies.
International Nuclear Information System (INIS)
Manakov, S V; Santini, P M
2008-01-01
We have recently solved the inverse scattering problem for one-parameter families of vector fields, and used this result to construct the formal solution of the Cauchy problem for a class of integrable nonlinear partial differential equations in multidimensions, including the second heavenly equation of Plebanski and the dispersionless Kadomtsev-Petviashvili (dKP) equation. We showed, in particular, that the associated inverse problems can be expressed in terms of nonlinear Riemann-Hilbert problems on the real axis. In this paper, we make use of the nonlinear Riemann-Hilbert problem of dKP (i) to construct the longtime behaviour of the solutions of its Cauchy problem; (ii) to characterize a class of implicit solutions; (iii) to elucidate the spectral mechanism causing the gradient catastrophe of localized solutions of dKP, at finite time as well as in the longtime regime, and the corresponding universal behaviours near breaking
Energy Technology Data Exchange (ETDEWEB)
Manakov, S V [Landau Institute for Theoretical Physics, Moscow (Russian Federation); Santini, P M [Dipartimento di Fisica, Universita di Roma ' La Sapienza' , and Istituto Nazionale di Fisica Nucleare, Sezione di Roma 1, Piazz.le Aldo Moro 2, I-00185 Rome (Italy)
2008-02-08
We have recently solved the inverse scattering problem for one-parameter families of vector fields, and used this result to construct the formal solution of the Cauchy problem for a class of integrable nonlinear partial differential equations in multidimensions, including the second heavenly equation of Plebanski and the dispersionless Kadomtsev-Petviashvili (dKP) equation. We showed, in particular, that the associated inverse problems can be expressed in terms of nonlinear Riemann-Hilbert problems on the real axis. In this paper, we make use of the nonlinear Riemann-Hilbert problem of dKP (i) to construct the longtime behaviour of the solutions of its Cauchy problem; (ii) to characterize a class of implicit solutions; (iii) to elucidate the spectral mechanism causing the gradient catastrophe of localized solutions of dKP, at finite time as well as in the longtime regime, and the corresponding universal behaviours near breaking.
International Nuclear Information System (INIS)
Sierra, Germán
2014-01-01
We construct a Hamiltonian H R whose discrete spectrum contains, in a certain limit, the Riemann zeros. H R is derived from the action of a massless Dirac fermion living in a domain of Rindler spacetime, in 1 + 1 dimensions, which has a boundary given by the world line of a uniformly accelerated observer. The action contains a sum of delta function potentials that can be viewed as partially reflecting moving mirrors. An appropriate choice of the accelerations of the mirrors, provide primitive periodic orbits that are associated with the prime numbers p, whose periods, as measured by the observer's clock, are logp. Acting on the chiral components of the fermion χ ∓ , H R becomes the Berry–Keating Hamiltonian ±(x p-hat + p-hat x)/2, where x is identified with the Rindler spatial coordinate and p-hat with the conjugate momentum. The delta function potentials give the matching conditions of the fermion wave functions on both sides of the mirrors. There is also a phase shift e iϑ for the reflection of the fermions at the boundary where the observer sits. The eigenvalue problem is solved by transfer matrix methods in the limit where the reflection amplitudes become infinitesimally small. We find that, for generic values of ϑ, the spectrum is a continuum where the Riemann zeros are missing, as in the adelic Connes model. However, for some values of ϑ, related to the phase of the zeta function, the Riemann zeros appear as discrete eigenvalues that are immersed in the continuum. We generalize this result to the zeros of Dirichlet L-functions, which are associated to primitive characters, that are encoded in the reflection coefficients of the mirrors. Finally, we show that the Hamiltonian associated to the Riemann zeros belongs to class AIII, or chiral GUE, of the Random Matrix Theory. (paper)
2016-06-08
Ideal Magnetohydrodynamics,” J. Com- put. Phys., Vol. 153, No. 2, 1999, pp. 334–352. [14] Tang, H.-Z. and Xu, K., “A high-order gas -kinetic method for...notwithstanding any other provision of law , no person shall be subject to any penalty for failing to comply with a collection of information if it does...Riemann-solver-free spacetime discontinuous Galerkin method for general conservation laws to solve compressible magnetohydrodynamics (MHD) equations. The
International Nuclear Information System (INIS)
Li Jiequan; Li Qibing; Xu Kun
2011-01-01
The generalized Riemann problem (GRP) scheme for the Euler equations and gas-kinetic scheme (GKS) for the Boltzmann equation are two high resolution shock capturing schemes for fluid simulations. The difference is that one is based on the characteristics of the inviscid Euler equations and their wave interactions, and the other is based on the particle transport and collisions. The similarity between them is that both methods can use identical MUSCL-type initial reconstructions around a cell interface, and the spatial slopes on both sides of a cell interface involve in the gas evolution process and the construction of a time-dependent flux function. Although both methods have been applied successfully to the inviscid compressible flow computations, their performances have never been compared. Since both methods use the same initial reconstruction, any difference is solely coming from different underlying mechanism in their flux evaluation. Therefore, such a comparison is important to help us to understand the correspondence between physical modeling and numerical performances. Since GRP is so faithfully solving the inviscid Euler equations, the comparison can be also used to show the validity of solving the Euler equations itself. The numerical comparison shows that the GRP exhibits a slightly better computational efficiency, and has comparable accuracy with GKS for the Euler solutions in 1D case, but the GKS is more robust than GRP. For the 2D high Mach number flow simulations, the GKS is absent from the shock instability and converges to the steady state solutions faster than the GRP. The GRP has carbuncle phenomena, likes a cloud hanging over exact Riemann solvers. The GRP and GKS use different physical processes to describe the flow motion starting from a discontinuity. One is based on the assumption of equilibrium state with infinite number of particle collisions, and the other starts from the non-equilibrium free transport process to evolve into an
BrandSpace : disaini uurimine ja toote suunamine / Brett Steele
Steele, Brett
2003-01-01
Tutvustatakse kolme näidet uurimis- ja disainiprojektist, millega tegeldakse AADRL-i Disainiuurimislaboratooriumis, Londoni Architectural Accociation School of Architecture arhitektuuriteooria ja disaini magistrikursustel. Iga projekt rõhutab veidi erinevat aspekti tänapäevase arhitektuurse ruumi, urbanismi ja teiste meediatoodete läbipõimunud suhetes
Some Aspects of Epilepsy and Convulsions in Childhood | Brett ...
African Journals Online (AJOL)
The diagnostic and therapeutic problems of epilepsy and convulsions in childhood are reviewed. Their non-specific aetiology is stressed, particularly with neonatal convulsions and infantile spasms. The role of febrile convulsions in causing later temporal lobe epilepsy and gross neurological deficit, underlines the ...
06 Brett van Niekerk and Manoj S. Maharajx
African Journals Online (AJOL)
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(now Zimbabwe, and colonial Mozambique were involved in a border war against insurgents ... supply routes and the protocols to gain entry to the bases. .... gateway by government, possibly with foreign assistance, and DDoS attacks against.
The Equation Δ u + ∇φ· ∇u = 8πc(1-heu) on a Riemann Surface
International Nuclear Information System (INIS)
Wang Meng
2009-12-01
Let M be a compact Riemann surface, h(x) a positive smooth function on M, and φ(x) a smooth function on M which satisfies that ∫ M e φ dV g = 1. In this paper, we consider the functional J(u) = 2 1 ∫ M |∇u| 2 e φ dV g +8πc ∫ M ue φ dV g -8πclog ∫ M he u+φ dV g . We give a sufficient condition under which J achieves its minimum for c ≤ inf xelement ofM Φ(x). (author)
Rosatti, Giorgio; Zugliani, Daniel
2015-03-01
In a two-phase free-surface flow, the transition from a mobile-bed condition to a fixed-bed one (and vice versa) occurs at a sharp interface across which the relevant system of partial differential equations changes abruptly. This leads to the possibility of conceiving a new type of Riemann Problem (RP), which we have called Composite Riemann Problem (CRP), where not only the initial constant values of the variables but also the system of equations change from left to right of a discontinuity. In this paper, we present a strategy for solving a CRP by reducing it to a standard RP of a single, composite system of equations. This can be obtained by combining the two original systems by means of a suitable weighting function, namely the erodibility variable, and the introduction of an appropriate differential equation for this quantity. In this way, the CRP problem can be analyzed theoretically with standard methods, and the features of the solutions can be clearly identified. In particular, a stationary contact wave is able to correctly describe the sharp transition between mobile- and fixed-bed conditions. A finite volume scheme based on the Multiple Averages Generalized Roe approach (Rosatti and Begnudelli (2013) [22]) was used to numerically solve the fixed-mobile CRP. Several test cases demonstrate the effectiveness, exact well balanceness and high accuracy of the scheme when applied to problems that fall within the physical range of applicability of the relevant mathematical model.
Owolabi, Kolade M.
2018-03-01
In this work, we are concerned with the solution of non-integer space-fractional reaction-diffusion equations with the Riemann-Liouville space-fractional derivative in high dimensions. We approximate the Riemann-Liouville derivative with the Fourier transform method and advance the resulting system in time with any time-stepping solver. In the numerical experiments, we expect the travelling wave to arise from the given initial condition on the computational domain (-∞, ∞), which we terminate in the numerical experiments with a large but truncated value of L. It is necessary to choose L large enough to allow the waves to have enough space to distribute. Experimental results in high dimensions on the space-fractional reaction-diffusion models with applications to biological models (Fisher and Allen-Cahn equations) are considered. Simulation results reveal that fractional reaction-diffusion equations can give rise to a range of physical phenomena when compared to non-integer-order cases. As a result, most meaningful and practical situations are found to be modelled with the concept of fractional calculus.
Ji, Xing; Zhao, Fengxiang; Shyy, Wei; Xu, Kun
2018-03-01
Most high order computational fluid dynamics (CFD) methods for compressible flows are based on Riemann solver for the flux evaluation and Runge-Kutta (RK) time stepping technique for temporal accuracy. The advantage of this kind of space-time separation approach is the easy implementation and stability enhancement by introducing more middle stages. However, the nth-order time accuracy needs no less than n stages for the RK method, which can be very time and memory consuming due to the reconstruction at each stage for a high order method. On the other hand, the multi-stage multi-derivative (MSMD) method can be used to achieve the same order of time accuracy using less middle stages with the use of the time derivatives of the flux function. For traditional Riemann solver based CFD methods, the lack of time derivatives in the flux function prevents its direct implementation of the MSMD method. However, the gas kinetic scheme (GKS) provides such a time accurate evolution model. By combining the second-order or third-order GKS flux functions with the MSMD technique, a family of high order gas kinetic methods can be constructed. As an extension of the previous 2-stage 4th-order GKS, the 5th-order schemes with 2 and 3 stages will be developed in this paper. Based on the same 5th-order WENO reconstruction, the performance of gas kinetic schemes from the 2nd- to the 5th-order time accurate methods will be evaluated. The results show that the 5th-order scheme can achieve the theoretical order of accuracy for the Euler equations, and present accurate Navier-Stokes solutions as well due to the coupling of inviscid and viscous terms in the GKS formulation. In comparison with Riemann solver based 5th-order RK method, the high order GKS has advantages in terms of efficiency, accuracy, and robustness, for all test cases. The 4th- and 5th-order GKS have the same robustness as the 2nd-order scheme for the capturing of discontinuous solutions. The current high order MSMD GKS is a
International Nuclear Information System (INIS)
Doliwa, A.; Grinevich, P.; Nieszporski, M.; Santini, P. M.
2007-01-01
We present the sublattice approach, a procedure to generate, from a given integrable lattice, a sublattice which inherits its integrability features. We consider, as illustrative example of this approach, the discrete Moutard 4-point equation and its sublattice, the self-adjoint 5-point scheme on the star of the square lattice, which are relevant in the theory of the integrable discrete geometries and in the theory of discrete holomorphic and harmonic functions (in this last context, the discrete Moutard equation is called discrete Cauchy-Riemann equation). Therefore an integrable, at one energy, discretization of elliptic two-dimensional operators is considered. We use the sublattice point of view to derive, from the Darboux transformations and superposition formulas of the discrete Moutard equation, the Darboux transformations and superposition formulas of the self-adjoint 5-point scheme. We also construct, from algebro-geometric solutions of the discrete Moutard equation, algebro-geometric solutions of the self-adjoint 5-point scheme. In particular, we show that the corresponding restrictions on the finite-gap data are of the same type as those for the fixed energy problem for the two-dimensional Schroedinger operator. We finally use these solutions to construct explicit examples of discrete holomorphic and harmonic functions, as well as examples of quadrilateral surfaces in R 3
International Nuclear Information System (INIS)
Connes, A.; Kreimer, D.
2000-01-01
This paper gives a complete selfcontained proof of our result (1999) showing that renormalization in quantum field theory is a special instance of a general mathematical procedure of extraction of finite values based on the Riemann-Hilbert problem. We shall first show that for any quantum field theory, the combinatorics of Feynman graphs gives rise to a Hopf algebra H which is commutative asan algebra. It is the dual Hopf algebra of the enveloping algebra of a Lie algebra G whose basis is labelled by the one particle irreducible Feynman graphs. The Lie bracket of two such graphs is computed from insertions of one graph in the other and vice versa. The corresponding Lie group G is the group of characters of H. We show then that, using dimensional regularization, the bare (unrenormalized) theory gives rise to a loop γ(z) element of G, z element of C, where C is a small circle of complex dimensions around the integer dimension D of space-time. Our main result is that the renormalized theory is just the evaluation at z=D of the holomorphic part γ + of the Birkhoff decomposition of γ. We begin to analyse the group G and show that it is a semi-direct product of an easily understood abelian group by a highly non-trivial group closely tied up with groups of diffeomorphisms. (orig.)
International Nuclear Information System (INIS)
Balsara, Dinshaw S.; Amano, Takanobu; Garain, Sudip; Kim, Jinho
2016-01-01
In various astrophysics settings it is common to have a two-fluid relativistic plasma that interacts with the electromagnetic field. While it is common to ignore the displacement current in the ideal, classical magnetohydrodynamic limit, when the flows become relativistic this approximation is less than absolutely well-justified. In such a situation, it is more natural to consider a positively charged fluid made up of positrons or protons interacting with a negatively charged fluid made up of electrons. The two fluids interact collectively with the full set of Maxwell's equations. As a result, a solution strategy for that coupled system of equations is sought and found here. Our strategy extends to higher orders, providing increasing accuracy. The primary variables in the Maxwell solver are taken to be the facially-collocated components of the electric and magnetic fields. Consistent with such a collocation, three important innovations are reported here. The first two pertain to the Maxwell solver. In our first innovation, the magnetic field within each zone is reconstructed in a divergence-free fashion while the electric field within each zone is reconstructed in a form that is consistent with Gauss' law. In our second innovation, a multidimensionally upwinded strategy is presented which ensures that the magnetic field can be updated via a discrete interpretation of Faraday's law and the electric field can be updated via a discrete interpretation of the generalized Ampere's law. This multidimensional upwinding is achieved via a multidimensional Riemann solver. The multidimensional Riemann solver automatically provides edge-centered electric field components for the Stokes law-based update of the magnetic field. It also provides edge-centered magnetic field components for the Stokes law-based update of the electric field. The update strategy ensures that the electric field is always consistent with Gauss' law and the magnetic field is
Energy Technology Data Exchange (ETDEWEB)
Balsara, Dinshaw S., E-mail: dbalsara@nd.edu [Physics Department, University of Notre Dame (United States); Amano, Takanobu, E-mail: amano@eps.s.u-tokyo.ac.jp [Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033 (Japan); Garain, Sudip, E-mail: sgarain@nd.edu [Physics Department, University of Notre Dame (United States); Kim, Jinho, E-mail: jkim46@nd.edu [Physics Department, University of Notre Dame (United States)
2016-08-01
In various astrophysics settings it is common to have a two-fluid relativistic plasma that interacts with the electromagnetic field. While it is common to ignore the displacement current in the ideal, classical magnetohydrodynamic limit, when the flows become relativistic this approximation is less than absolutely well-justified. In such a situation, it is more natural to consider a positively charged fluid made up of positrons or protons interacting with a negatively charged fluid made up of electrons. The two fluids interact collectively with the full set of Maxwell's equations. As a result, a solution strategy for that coupled system of equations is sought and found here. Our strategy extends to higher orders, providing increasing accuracy. The primary variables in the Maxwell solver are taken to be the facially-collocated components of the electric and magnetic fields. Consistent with such a collocation, three important innovations are reported here. The first two pertain to the Maxwell solver. In our first innovation, the magnetic field within each zone is reconstructed in a divergence-free fashion while the electric field within each zone is reconstructed in a form that is consistent with Gauss' law. In our second innovation, a multidimensionally upwinded strategy is presented which ensures that the magnetic field can be updated via a discrete interpretation of Faraday's law and the electric field can be updated via a discrete interpretation of the generalized Ampere's law. This multidimensional upwinding is achieved via a multidimensional Riemann solver. The multidimensional Riemann solver automatically provides edge-centered electric field components for the Stokes law-based update of the magnetic field. It also provides edge-centered magnetic field components for the Stokes law-based update of the electric field. The update strategy ensures that the electric field is always consistent with Gauss' law and the magnetic field is
Dynamics on the Riemann Sphere
DEFF Research Database (Denmark)
Petersen, Carsten Lunde
Collection of research papers on holomorphic dynamical systems with an introduction to Bodil Branners works on the field. Contributions: John Milnor: On Lattès Maps. Carsten Lunde Petersen and Tan Lei: Branner-Hubbard motions and attracting dynamics. Artur Avila and Mikhail Lyubich: Examples...
Balsara, Dinshaw S.; Garain, Sudip; Taflove, Allen; Montecinos, Gino
2018-02-01
The Finite Difference Time Domain (FDTD) scheme has served the computational electrodynamics community very well and part of its success stems from its ability to satisfy the constraints in Maxwell's equations. Even so, in the previous paper of this series we were able to present a second order accurate Godunov scheme for computational electrodynamics (CED) which satisfied all the same constraints and simultaneously retained all the traditional advantages of Godunov schemes. In this paper we extend the Finite Volume Time Domain (FVTD) schemes for CED in material media to better than second order of accuracy. From the FDTD method, we retain a somewhat modified staggering strategy of primal variables which enables a very beneficial constraint-preservation for the electric displacement and magnetic induction vector fields. This is accomplished with constraint-preserving reconstruction methods which are extended in this paper to third and fourth orders of accuracy. The idea of one-dimensional upwinding from Godunov schemes has to be significantly modified to use the multidimensionally upwinded Riemann solvers developed by the first author. In this paper, we show how they can be used within the context of a higher order scheme for CED. We also report on advances in timestepping. We show how Runge-Kutta IMEX schemes can be adapted to CED even in the presence of stiff source terms brought on by large conductivities as well as strong spatial variations in permittivity and permeability. We also formulate very efficient ADER timestepping strategies to endow our method with sub-cell resolving capabilities. As a result, our method can be stiffly-stable and resolve significant sub-cell variation in the material properties within a zone. Moreover, we present ADER schemes that are applicable to all hyperbolic PDEs with stiff source terms and at all orders of accuracy. Our new ADER formulation offers a treatment of stiff source terms that is much more efficient than previous ADER
On the record: Professor Rachel Jewkes | Gould | South African ...
African Journals Online (AJOL)
South African Crime Quarterly. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 43 (2013) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should load ...
Tööpuudus 29%, palavikku pole / Rachel Donadio
Donadio, Rachel
2010-01-01
Lõuna-Hispaanias asuvas Cádizis on töötus 29%, ometi pole eurotsooni kõrgeim tööpuuduse määr tekitanud linnas sügavat sotsiaalset rahutust ega massilisi proteste, sest üsna kõrge elukvaliteedi tagavad töötutele kompleksne turvavõrk, mis koosneb varimajandusest, perekonna toetusest ja valitsuse toetusest
Flexible staffing solutions and its impact on customer satisfaction / Richard Francis Brett
Brett, Richard Francis
2007-01-01
The face of the workplace has changed dramatically over the past decade and most organisations have to survive in a fiercely competitive global economy. The impact of the competitive changes, especially in the service environment has become critical and quality service is considered an essential strategy for success and survival in today's competitive environment. Organisations are continuously searching for ways to improve their performance and create a sustainable competitive advantage. Con...
Baez, Joao-Joan; Lapidaryus, Michelle; Siegel, Edward Carl-Ludwig
2013-03-01
Riemann-hypothesis physics-proof combines: Siegel-Antono®-Smith[AMS Joint Mtg.(2002)- Abs.973-03-126] digits on-average statistics HIll[Am. J. Math 123, 3, 887(1996)] logarithm-function's (1,0)- xed-point base =units =scale-invariance proven Newcomb [Am. J. Math. 4, 39(1881)]-Weyl[Goett. Nachr.(1914); Math. Ann.7, 313(1916)]-Benford[Proc. Am. Phil. Soc. 78, 4, 51(1938)]-law [Kac,Math. of Stat.-Reasoning(1955); Raimi, Sci. Am. 221, 109(1969)] algebraic-inversion to ONLY Bose-Einstein quantum-statistics(BEQS) with digit d = 0 gapFUL Bose-Einstein Condensation(BEC) insight that digits are quanta are bosons because bosons are and always were quanta are and always were digits, via Siegel-Baez category-semantics tabular list-format matrix truth-table analytics in Plato-Aristotle classic ''square-of-opposition'' : FUZZYICS =CATEGORYICS/Category-Semantics, with Goodkind Bose-Einstein Condensation (BEC) ABOVE ground-state with/and Rayleigh(cut-limit of ''short-cut method''1870)-Polya(1922)-''Anderson''(1958) localization [Doyle and Snell,Random-Walks and Electrical-Networks, MAA(1981)-p.99-100!!!] in Brillouin[Wave-Propagation in Periodic-Structures(1946) Dover(1922)]-Hubbard-Beeby[J.Phys.C(1967)] Siegel[J.Nonxline-Sol.40,453(1980)] generalized-disorder collective-boson negative-dispersion mode-softening universality-principle(G...P) first use of the ``square-of-opposition'' in physics since Plato and Aristote!!!
Bosonization on higher genus Riemann surfaces
International Nuclear Information System (INIS)
Alvarez-Gaume, L.; Moore, G.; Nelson, P.; Vafa, C.
1987-01-01
We prove the equivalence between certain fermionic and bosonic theories in two spacetime dimensions. The theories have fields of arbitrary spin on compact surfaces with any number of handles. Global considerations required that we add new topological terms to the bosonic action. The proof that our prescritpion is correct relies on methods of complex algebraic geometry. (orig.)
The Einstein tensor characterizing some Riemann spaces
International Nuclear Information System (INIS)
Rahman, M.S.
1993-07-01
A formal definition of the Einstein tensor is given. Mention is made of how this tensor plays a role of expressing certain conditions in a precise form. The cases of reducing the Einstein tensor to a zero tensor are studied on its merit. A lucid account of results, formulated as theorems, on Einstein symmetric and Einstein recurrent spaces is then presented. (author). 5 refs
Fardet, Tanguy; Bottani, Samuel; Métens, Stéphane; Monceau, Pascal
2018-06-01
The Quorum Percolation model (QP) has been designed in the context of neurobiology to describe the initiation of activity bursts occurring in neuronal cultures from the point of view of statistical physics rather than from a dynamical synchronization approach. This paper aims at investigating an extension of the original QP model by taking into account the presence of inhibitory neurons in the cultures (IQP model). The first part of this paper is focused on an equivalence between the presence of inhibitory neurons and a reduction of the network connectivity. By relying on a simple topological argument, we show that the mean activation behavior of networks containing a fraction η of inhibitory neurons can be mapped onto purely excitatory networks with an appropriately modified wiring, provided that η remains in the range usually observed in neuronal cultures, namely η ⪅ 20%. As a striking result, we show that such a mapping enables to predict the evolution of the critical point of the IQP model with the fraction of inhibitory neurons. In a second part, we bridge the gap between the description of bursts in the framework of percolation and the temporal description of neural networks activity by showing how dynamical simulations of bursts with an adaptive exponential integrate-and-fire model lead to a mean description of bursts activation which is captured by Quorum Percolation.
Abuse of Rachel Carson and Misuse of DDT Science in the Service of Environmental Deregulation.
Yang, Jingxiang; Ward, Michael D; Kahr, Bart
2017-08-14
Fake news?? The contact insecticide DDT has been reappraised as a safe, life-saving compound by special interest groups committed to repealing environmental regulations. It is shown in this essay how some specific toxicological data has been misused by those aiming to disingenuously influence public policy. Graphic: Pestroy, a DDT-laced coating marketed in 1946 by Sherwin-Williams Research Laboratories. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.
Tucker-Raymond, Eli; Varelas, Maria; Pappas, Christine C.; Korzh, Alla; Wentland, Ashley
2007-02-01
In this research we put forth a theoretical framework that explores the nature and value of multi-modal narratives as a tool for studying young children's conceptions of themselves as scientists as they exist in relation to scientists out in the world. This framework shapes and is shaped by an empirical study that took place within the context of a year-long program that engaged children in integrated science-literacy experiences around two units -- one on matter and one on a forest ecosystem. Thirty-six children were asked twice to draw and discuss two pictures of times they were scientists. We present our findings in two main ways. First, we use case studies of three students (one each in the first, second, and third grade) to show how the various constructs in the theoretical framework come together in the empirical study, and to explore in depth the various ideas that the children revealed. Second, we share a summative descriptive analysis of the differences between the pre and the post interviews. One of the important findings included the increase in the number of pictures from the pre-interview to the post interview in which children represented themselves as scientists (31 to 61). The children also showed themselves and scientists out in the world as engaging in practices with a range of materials, for a variety of purposes, and with particular kinds of epistemological commitments.
VIG Seminar April 5, 2018 Rachel Van Duyne and Melissa Fernandez | Center for Cancer Research
Please join us for the Virology Interest Group Seminar on Thursday, April 5th, from 2:30 until 3:30 in Frederick, Building 549, Conference Room A. The seminar will also be broadcasted to Bethesda, Building 50, Room 2328.
Directory of Open Access Journals (Sweden)
Jonathan Carr-West
2018-04-01
Full Text Available Local Government in England: Centralisation, Autonomy and Control is a serious book and an important contribution to the scholarship around local government. It opens however, with a pleasingly comic tableau as academics from England, Portugal and Poland bicker amiably at a conference and on Twitter about whose country is really the most centralised. The rest of the book is devoted to showing why the English academics were right, why it matters and what should be done about it. The main thrust of the text is an analysis of the impact of the dominant policy narratives around centralism and localism. The argument that Copus, Wall and Roberts put forward could be boiled down to the assertion that the problem with local government in England is that it is neither local nor government. But to make this case they first helpfully unpack several sets of concepts that are all too often elided together.
International Nuclear Information System (INIS)
1988-01-01
The volume contains over a hundred abstracts of lectures covering a wide variety of subjects in the field of free electron lasers. Many features of lasing were observed over a range of problems, and experiments which resulted in finding ideal or near-ideal techniques for gaining better and more efficient optical power have been carried out
Riemann-Cartan geometry of nonlinear disclination mechanics
Yavari, A.; Goriely, A.
2012-01-01
In the continuous theory of defects in nonlinear elastic solids, it is known that a distribution of disclinations leads, in general, to a non-trivial residual stress field. To study this problem, we consider the particular case of determining
Riemann Geometric Color-Weak Compensationfor Individual Observers
Kojima, Takanori; Mochizuki, Rika; Lenz, Reiner; Chao, Jinhui
2014-01-01
We extend a method for color weak compensation based on the criterion of preservation of subjective color differences between color normal and color weak observers presented in [2]. We introduce a new algorithm for color weak compensation using local affine maps between color spaces of color normal and color weak observers. We show howto estimate the local affine map and how to determine correspondences between the origins of local coordinates in color spaces of color normal and color weak ob...
Multi-loop string amplitudes and Riemann surfaces
International Nuclear Information System (INIS)
Taylor, J.G.
1986-01-01
The paper was presented at the workshop on 'Supersymmetry and its applications', Cambridge, United Kingdom, 1985. Super-string theory is discussed under the following topic headings: the functional approach to the string amplitude, Rieman surfaces, the determinants Δsub(epsilon)(1) and Δsub(epsilon)(2), Green's functions, total amplitude, and divergence analysis. (U.K.)
An Introduction to Riemann Surfaces, Algebraic Curves and Moduli Spaces
Schlichenmaier, Martin
2007-01-01
This book gives an introduction to modern geometry. Starting from an elementary level the author develops deep geometrical concepts, playing an important role nowadays in contemporary theoretical physics. He presents various techniques and viewpoints, thereby showing the relations between the alternative approaches. At the end of each chapter suggestions for further reading are given to allow the reader to study the touched topics in greater detail. This second edition of the book contains two additional more advanced geometric techniques: (1) The modern language and modern view of Algebraic Geometry and (2) Mirror Symmetry. The book grew out of lecture courses. The presentation style is therefore similar to a lecture. Graduate students of theoretical and mathematical physics will appreciate this book as textbook. Students of mathematics who are looking for a short introduction to the various aspects of modern geometry and their interplay will also find it useful. Researchers will esteem the book as reliable ...
Riemann-Cartan geometry of nonlinear disclination mechanics
Yavari, A.
2012-03-23
In the continuous theory of defects in nonlinear elastic solids, it is known that a distribution of disclinations leads, in general, to a non-trivial residual stress field. To study this problem, we consider the particular case of determining the residual stress field of a cylindrically symmetric distribution of parallel wedge disclinations. We first use the tools of differential geometry to construct a Riemannian material manifold in which the body is stress-free. This manifold is metric compatible, has zero torsion, but has non-vanishing curvature. The problem then reduces to embedding this manifold in Euclidean 3-space following the procedure of a classical nonlinear elastic problem. We show that this embedding can be elegantly accomplished by using Cartan\\'s method of moving frames and compute explicitly the residual stress field for various distributions in the case of a neo-Hookean material. © 2012 The Author(s).
Quantum Riemann surfaces. Pt. 1. The unit disc
Energy Technology Data Exchange (ETDEWEB)
Klimek, S.; Lesniewski, A. (Harvard Univ., Cambridge, MA (United States))
1992-05-01
We construct a non-commutative C{sup *}-algebra C{sub {mu}}(anti U) which is a quantum deformation of the algebra of continuous functions on the closed unit disc anti U.C{sub {mu}}(anti U) is generated by the Toeplitz operators on a suitable Hilbert space of holomorphic functions on U. (orig.).
A Polyakov action on Riemann surfaces. Pt. 2
International Nuclear Information System (INIS)
Zucchini, R.
1991-11-01
The model independent study of the Polyakov action is continued on an arbitrary compact surface without boundary of genus larger than 2 as the general solution of the relevant conformal Ward identity. A general formula for the Polyakov action and an explicit calculation of the energy-momentum tensor density is provided. The general geometric setting of the construction is described in detail. It is shown that the Polyakov action defines a distribution of finite dimensional directions in the holomorphic tangent bundle of the manifold of Beltrami differentials. It is further argued that motions parallel to such distribution correspond to Polyakov's SL(2,C) symmetry transformations. Owing to the existence of renormalization ambiguities on a topologically non-trivial surface, the energy-momentum tensor needs not be invariant under the full SL(2,C) symmetry. The residual SL(2,C) symmetry is characterized geometrically. (author) 31 refs
Integrable equations, addition theorems, and the Riemann-Schottky problem
International Nuclear Information System (INIS)
Buchstaber, Viktor M; Krichever, I M
2006-01-01
The classical Weierstrass theorem claims that, among the analytic functions, the only functions admitting an algebraic addition theorem are the elliptic functions and their degenerations. This survey is devoted to far-reaching generalizations of this result that are motivated by the theory of integrable systems. The authors discovered a strong form of the addition theorem for theta functions of Jacobian varieties, and this form led to new approaches to known problems in the geometry of Abelian varieties. It is shown that strong forms of addition theorems arise naturally in the theory of the so-called trilinear functional equations. Diverse aspects of the approaches suggested here are discussed, and some important open problems are formulated.
Beltrami algebra and symmetry of Beltrami equation on Riemann surfaces
International Nuclear Information System (INIS)
Guo Hanying; Xu Kaiwen; Shen Jianmin; Wang Shikun
1989-12-01
It is shown that the Beltrami equation has an infinite dimensional symmetry, namely the Beltrami algebra, on its solution spaces. The Beltrami algebra with central extension and its supersymmetric version are explicitly found. (author). 12 refs
Van Cutsem, E; Li, C-P; Nowara, E; Aprile, G; Moore, M; Federowicz, I; Van Laethem, J-L; Hsu, C; Tham, C K; Stemmer, S M; Lipp, R; Zeaiter, A; Fittipaldo, A; Csutor, Z; Klughammer, B; Meng, X; Ciuleanu, T
2014-11-25
This phase II, open-label, randomised study evaluated whether patients with metastatic pancreatic cancer receiving erlotinib/gemcitabine derived survival benefits from increasing the erlotinib dose. After a 4-week run-in period (gemcitabine 1000 mg m(-2) once weekly plus erlotinib 100 mg per day), patients with metastatic pancreatic cancer who developed grade 0/1 rash were randomised to receive gemcitabine plus erlotinib dose escalation (150 mg, increasing by 50 mg every 2 weeks (maximum 250 mg); n=71) or gemcitabine plus standard-dose erlotinib (100 mg per day; n=75). The primary end point was to determine whether overall survival (OS) was improved by increasing the erlotinib dose. Secondary end points included progression-free survival (PFS), incidence of grade ⩾2 rash, and safety. Erlotinib dose escalation induced grade ⩾2 rash in 29 out of 71 (41.4%) patients compared with 7 out of 75 (9.3%) patients on standard dose. Efficacy was not significantly different in the dose-escalation arm compared with the standard-dose arm (OS: median 7.0 vs 8.4 months, respectively, hazard ratio (HR), 1.26, 95% confidence interval (CI): 0.88-1.80; P=0.2026; PFS: median 3.5 vs 4.5 months, respectively, HR, 1.09, 95% CI: 0.77-1.54; P=0.6298). Incidence of adverse events was comparable between randomised arms. The erlotinib dose-escalation strategy induced rash in some patients; there was no evidence that the higher dose translated into increased benefit.
A Curious Case of Caveats and Causes
DEFF Research Database (Denmark)
Blyth, Mark
2014-01-01
Review symposium contribution. Banking Across Boundaries: Placing Finance in Capitalism / Brett Christophers. Wiley-Blackwell, Chichester, Sussex, 2013, 302 pages. Participants: Jamie Peck; Fred Block; Mark Blyth; Ewald Engelen; Brett Christophers.......Review symposium contribution. Banking Across Boundaries: Placing Finance in Capitalism / Brett Christophers. Wiley-Blackwell, Chichester, Sussex, 2013, 302 pages. Participants: Jamie Peck; Fred Block; Mark Blyth; Ewald Engelen; Brett Christophers....
Statistical properties of the zeros of zeta functions - beyond the Riemann case
International Nuclear Information System (INIS)
Bogomolny, E.; Leboeuf, P.
1993-09-01
The statistical distribution of the zeros of Dirichlet L-functions is investigated both analytically and numerically. Using the Hardy-Littlewood conjecture about the distribution of primes it is shown that the two-point correlation function of these zeros coincides with that for eigenvalues of the Gaussian unitary ensemble of random matrices, and that the distributions of zeros of different L-functions are statistically independent. Applications of these results to Epstein's zeta functions are shortly discussed. (authors) 30 refs., 3 figs., 1 tab
The Riemann Solution for the Injection of Steam and Nitrogen in a Porous Medium
Lambert, W.; Marchesin, D.; Bruining, J.
2009-01-01
We solve the model for the flow of nitrogen, vapor, and water in a porous medium, neglecting compressibility, heat conductivity, and capillary effects. Our choice of injection conditions is determined by the application to clean up polluted sites. We study all mathematical structures, such as
Study of the Issues of Computational Aerothermodynamics Using a Riemann Solver
2008-07-01
should satisfy positiv - ity and not violate the Second Law of Thermodynamics (commonly called the entropy condition). Positivity preserving schemes...can be seen that N2 starts to dissociate around 6000 K - 12,000 K. 5.3 Conclusion This work has produced quantitative dividing lines between a regime...This figure provides a great deal of quantitative information and should be very useful to the high-speed flow CFD community. This work has also
Quantum Yang-Mills theory of Riemann surfaces and conformal field theory
International Nuclear Information System (INIS)
Killingback, T.P.
1989-01-01
It is shown that Yang-Mills theory on a smooth surface, when suitably quantized, is a topological quantum field theory. This topological gauge theory is intimately related to two-dimensional conformal field theory. It is conjectured that all conformal field theories may be obtained from Yang-Mills theory on smooth surfaces. (orig.)
Vargas, José G
2014-01-01
This is a book that the author wishes had been available to him when he was student. It reflects his interest in knowing (like expert mathematicians) the most relevant mathematics for theoretical physics, but in the style of physicists. This means that one is not facing the study of a collection of definitions, remarks, theorems, corollaries, lemmas, etc. but a narrative - almost like a story being told - that does not impede sophistication and deep results. It covers differential geometry far beyond what general relativists perceive they need to know. And it introduces readers to other areas
Controlling lightwave in Riemann space by merging geometrical optics with transformation optics.
Liu, Yichao; Sun, Fei; He, Sailing
2018-01-11
In geometrical optical design, we only need to choose a suitable combination of lenses, prims, and mirrors to design an optical path. It is a simple and classic method for engineers. However, people cannot design fantastical optical devices such as invisibility cloaks, optical wormholes, etc. by geometrical optics. Transformation optics has paved the way for these complicated designs. However, controlling the propagation of light by transformation optics is not a direct design process like geometrical optics. In this study, a novel mixed method for optical design is proposed which has both the simplicity of classic geometrical optics and the flexibility of transformation optics. This mixed method overcomes the limitations of classic optical design; at the same time, it gives intuitive guidance for optical design by transformation optics. Three novel optical devices with fantastic functions have been designed using this mixed method, including asymmetrical transmissions, bidirectional focusing, and bidirectional cloaking. These optical devices cannot be implemented by classic optics alone and are also too complicated to be designed by pure transformation optics. Numerical simulations based on both the ray tracing method and full-wave simulation method are carried out to verify the performance of these three optical devices.
Geometry of the fundamental interactions on Riemann's legacy to high energy physics and cosmology
Maia, M D
2011-01-01
The Yang-Mills theory of gauge interactions is a prime example of interdisciplinary mathematics and advanced physics. Its historical development is a fascinating window into the ongoing struggle of mankind to understand nature. The discovery of gauge fields and their properties is the most formidable landmark of modern physics. The expression of the gauge field strength as the curvature associated to a given connection, places quantum field theory in the same geometrical footing as the gravitational field of general relativity which is naturally written in geometrical terms. The understanding of such geometrical property may help one day to write a unified field theory starting from symmetry principles. Of course, there are remarkable differences between the standard gauge fields and the gravitational field, which must be understood by mathematicians and physicists before attempting such unification. In particular, it is important to understand why gravitation is not a standard gauge field. This book presents...
The holographic dual of a Riemann problem in a large number of dimensions
Energy Technology Data Exchange (ETDEWEB)
Herzog, Christopher P.; Spillane, Michael [C.N. Yang Institute for Theoretical Physics, Department of Physics and Astronomy,Stony Brook University, Stony Brook, NY 11794 (United States); Yarom, Amos [Department of Physics, Technion,Haifa 32000 (Israel)
2016-08-22
We study properties of a non equilibrium steady state generated when two heat baths are initially in contact with one another. The dynamics of the system we study are governed by holographic duality in a large number of dimensions. We discuss the “phase diagram” associated with the steady state, the dual, dynamical, black hole description of this problem, and its relation to the fluid/gravity correspondence.
Asymptotic behavior of monodromy singularly perturbed differential equations on a Riemann surface
Simpson, Carlos
1991-01-01
This book concerns the question of how the solution of a system of ODE's varies when the differential equation varies. The goal is to give nonzero asymptotic expansions for the solution in terms of a parameter expressing how some coefficients go to infinity. A particular classof families of equations is considered, where the answer exhibits a new kind of behavior not seen in most work known until now. The techniques include Laplace transform and the method of stationary phase, and a combinatorial technique for estimating the contributions of terms in an infinite series expansion for the solution. Addressed primarily to researchers inalgebraic geometry, ordinary differential equations and complex analysis, the book will also be of interest to applied mathematicians working on asymptotics of singular perturbations and numerical solution of ODE's.
The Riemann Surface of Static Limit Dispersion Relation and Projective Spaces
Majewski, M; Meshcheryakov, D V; Tran Quang Tuyet
2004-01-01
The rigorous Bogoliubov's prove of the dispersion relations (DR) for pion-nucleon scattering is a good foundation for the static models. DR contain the small parameter (ratio of the pion-nucleon masses). The static models arise when this parameter goes to zero. The S-matrix in the static models has a block structure. Each block of the S-matrix has a finite order N\\times N and is a matrix of meromorphic functions of the light particle energy \\omega in the complex plane with cuts (-\\inf,-1], [+1, +\\inf). In the elastic case, it reduces to N functions S_{i}(\\omega) connected by N\\times N the crossing-symmetry matrix A. The unitarity and the crossing symmetry are the base for the system of nonlinear boundary value problems. It defines the analytical continuation of S_{i}(\\omega) from the physical sheet to the unphysical ones and can be treated as a system of nonlinear difference equations. The problem is solvable for any 2\\times 2 crossing-symmetry matrix A that permits one to calculate the Regge trajectories for...
Riemann solvers and numerical methods for fluid dynamics a practical introduction
Toro, Eleuterio F
2009-01-01
High resolution upwind and centred methods are a mature generation of computational techniques applicable to a range of disciplines, Computational Fluid Dynamics being the most prominent. This book gives a practical presentation of this class of techniques.
Generalized Riemann zeta-function regularization and Casimir energy for a piecewise uniform string
International Nuclear Information System (INIS)
Li Xinzhou; Shi Xin; Zhang Jianzu.
1990-12-01
The generalized zeta-function techniques will be utilized to investigate the Casimir energy for the transverse oscillations of a piecewise uniform closed string. We find that zeta-function regularization method can lead straightforwardly to a correct result. (author). 6 refs
The Riemann surface of static limit dispersion relation and projective spaces
International Nuclear Information System (INIS)
Majewski, M.; Meshcheryakov, V.A.; Meshcheryakov, D.V.; Tran Quang Tuyet
2004-01-01
The rigorous Bogolyubov's proof of the dispersion relations (DR) for pion-nucleon scattering is a good foundation for the static models. DR contain a small parameter (ratio of the pion-nucleon masses). The static models arise when this parameter goes to zero. The S-matrix in the static models has a block structure. Each block of the S-matrix has a finite order NxN and is a matrix of meromorphic functions of the light particle energy ω in the complex plane with cuts (-∞, -1], [+1,+∞). In the elastic case, it reduces to N functions S i (ω) connected by the NxN crossing-symmetry matrix A. The unitarity and the crossing symmetry are the base for the system of nonlinear boundary value problems. It defines the analytical continuation of S i (ω) from the physical sheet to the unphysical ones and can be treated as a system of nonlinear difference equations. The problem is solvable for any 2x2 crossing-symmetry matrix A that permits one to calculate the Regge trajectories for the SU(2) static model. It is shown that global analyses of this system can be carried out effectively in projective spaces P N-1 and P N . The connection between the spaces P N-1 and P N is discussed. Some particular solutions of the system are found
Changing gauge of second type for the election of Landau and tangential Cauchy-Riemann equations
International Nuclear Information System (INIS)
Laville, Guy
1980-01-01
For any type choice of gauge it is possible to get an equality between the Hamiltonian of a charge particle and an operator of second order which is associated with the boundary values of holomorphic functions of two complex variables [fr
Energy Technology Data Exchange (ETDEWEB)
Devanathan, Ram
2016-05-01
Five decades ago, Gordon Moore, who would go on to co-found Intel Corporation, made a prescient observation about the exponential advance of semiconductor technology with a corresponding decrease in device cost. His prediction about the pace of doubling of the number of transistors in an integrated circuit came to be known eponymously as Moore’s law and has held true for 50 years. He also foresaw, way back in 1965, the development of home computers, electronic controls in automobiles, portable communications systems, and electronic wrist watches. Moore’s fascinating life, characterized by relentless innovation, charity and breathtaking humility, is the subject of this comprehensive authorized biography. The enthralling narrative is the product of collaboration between an academic (Thackray), a technology historian (Brock) and a journalist (Jones), and draws its material from numerous interviews, Moore’s meticulously maintained notes and professional records, personal papers, industry data, published volumes, and news accounts.
Quigley, Rachel; Ghavamian, Parviz
2018-01-01
Abstract:The supernova remnant N49, located in the Large Magellanic Cloud (LMC), is widely researched because of its relatively young age and its location near a dense, dusty molecular cloud in the interstellar medium (ISM). N49 has entered into its radiative phase more quickly than to be expected for the age of this remnant. As a consequence, N49 is showing signs that the diffuse hot interior is starting to cool and recombine. Using existing integral field spectra of SNR N49, different Fe emission lines and other spectral lines were extracted via python tools, following a similar approach to Dopita et al. (2016). At optical wavelengths, the dependence of [OIII]5007/4363 ratio on shock velocity is evident. This diagnostic is important because the [OIII]-emitting zone in low-velocity shocks of the cooling post-shock gas is hot. As the shock velocity increases, the temperature indicated by the [OIII] parameter falls. The dependence of Fe depletion lines on shock velocity is rather weak. Using [FeIII]:[OIII] diagnostic, the properties of dust destruction and production of dust in the SNR can be determined. Using this method, line ratios for other emission lines can be compared to the MAPPINGS predictions of Allen et al. (2008) to study the range of shock speeds present in the supernova remnant, where radiative shocks are driven into interstellar gas.
2010-06-22
... of the draft guidelines please contact Rachel Lentz at (202) 566-2745. Please send any comments to Rachel Lentz at lentz.rachel@epa.gov no later than July 2, 2010. FOR FURTHER INFORMATION CONTACT: The U.S...
Interdisciplinary Perspectives on Culture, Conflict, and Negotiation
2009-08-28
negotiator cognition: Judgement accuracy and negotiation processes in individualistic and collectivistic cultures ", Organizational Behavior and Human...2004, Adair, Okumura, and Brett, 2001). Communication sequences are also affected by culture . Negotiators from collectivistic cultures use more... individualistic cultures (Adail and Brett, 2005; Adair, Okumura, and Brett, 2001). Research in DB/psychology has increasingly examined situational factors that
2011-09-29
.... Written comments should be sent to Rachel O'Malley at NOAA Fisheries, Office of International Affairs... fax (301- 713-2313) or e-mail ( Rachel.O'[email protected] ). FOR FURTHER INFORMATION CONTACT: Rachel O... for sign language interpretation or other auxiliary aids should be directed to Rachel O'Malley at (301...
Markfelder, Simon; Klingenberg, Christian
2018-03-01
In this paper we consider the isentropic compressible Euler equations in two space dimensions together with particular initial data. This data consists of two constant states, where one state lies in the lower and the other state in the upper half plane. The aim is to investigate whether there exists a unique entropy solution or if the convex integration method produces infinitely many entropy solutions. For some initial states this question has been answered by Feireisl and Kreml (J Hyperbolic Differ Equ 12(3):489-499, 2015), and also Chen and Chen (J Hyperbolic Differ Equ 4(1):105-122, 2007), where there exists a unique entropy solution. For other initial states Chiodaroli and Kreml (Arch Ration Mech Anal 214(3):1019-1049, 2014) and Chiodaroli et al. (Commun Pure Appl Math 68(7):1157-1190, 2015), showed that there are infinitely many entropy solutions. For still other initial states the question on uniqueness remained open and this will be the content of this paper. This paper can be seen as a completion of the aforementioned papers by showing that the solution is non-unique in all cases (except if the solution is smooth).
On the Riemann solutions of the balance equations for steam and water flow in a porous medium
Lambert, W.; Marchesin, D.; Bruining, J.
2005-01-01
Conservation laws have been used to model a variety of physical phenomena and therefore the theory for this class of equations is well developed. However, in many problems, such as transport of hot fluids and gases undergoing mass transfer, balance laws are required to describe the flow. As an
International Nuclear Information System (INIS)
Red'kov, V.M.; Ovsiyuk, E.M.; Ishkhanyan, A.M.
2013-01-01
The Schrodinger particle on the background of the 2D space of the constant positive curvature S 2 , a sphere in the 3D Euclidean space, is considered in the external magnetic field. By analogy with the case of the hyperbolic Lobachevsky plane H 2 , where quasi-Cartesian coordinates exist with the realization of H 2 as the Poincare half-plane, a specific system of quasi-Cartesian coordinates (x, y) in S 2 is introduced. It turns out that it is possible only if the two coordinates are complex and obey an additional restriction in order to present a real 2D space. The Schrodinger equation is solved using the method of separation of the variables in the both coordinate systems, cylindrical and quasi-Cartesian, the energy spectrum is the same. For parametrization of the space S 2 , one can use the coordinates (x, x*) or (y, y*), however, in this case the separability of the variables in the wave functions is lost. Constructed solutions may be of interest for describing charged particles in magnetic fields in the context of cosmological models, and for simulating the behavior of the particles in a specific field-configuration in the nano-physics. (authors)
B. Koren (Barry); M.R. Lewis; E.H. van Brummelen (Harald); B. van Leer
2001-01-01
textabstractA finite-volume method is presented for the computation of compressible flows of two immiscible fluids at very different densities. The novel ingredient in the method is a two-fluid linearized Godunov scheme, allowing for flux computations in case of different fluids (e.g., water and
2011-02-18
...-0800. FOR FURTHER INFORMATION CONTACT: Rachel O'Malley at (301) 713-9505. SUPPLEMENTARY INFORMATION.... Requests for sign language interpretation or other auxiliary aids should be directed to Rachel O'Malley at...
2013-03-18
... INFORMATION CONTACT: Rachel O'Malley at (301) 427-8373. SUPPLEMENTARY INFORMATION: The Advisory Committee to.... Requests for sign language interpretation or other auxiliary aids should be directed to Rachel O'Malley at...
2011-04-27
...-7945, [email protected] or Rachel Bennett, Environmental Protection Specialist, P.O. Box 129, Grand Canyon, Arizona 86023, 928-638-7326, Rachel[email protected] . SUPPLEMENTARY INFORMATION: If you wish to...
78 FR 64403 - Amendment to Standards and Practices for All Appropriate Inquiries
2013-10-29
... published at 78 FR 49690, on August 15 2013. FOR FURTHER INFORMATION CONTACT: Rachel Lentz, Office of... address: lentz.rachel@epa.gov . SUPPLEMENTARY INFORMATION: Because EPA received adverse comment, we are...
75 FR 7150 - Sunshine Act Meetings
2010-02-17
....3, 515.21, and 520.3--Request for Extension of Time. Contact Person for More Information: Rachel Dickon, Assistant Secretary, (202) 523-5725. Rachel Dickon, Assistant Secretary. [FR Doc. 2010-3063 Filed...
2012-07-26
... Colesville Road, Silver Spring, MD 20910. Written comments should be sent via email ( Rachel.O'[email protected] ). Comments may also be sent via mail to Rachel O'Malley at NMFS, Office of International Affairs, Room 12622, 1315 East-West Highway, Silver Spring, MD 20910. FOR FURTHER INFORMATION CONTACT: Rachel O...
78 FR 37245 - Submission for Review: OPM Form 1203-FX, Occupational Questionnaire
2013-06-20
... Personnel Management, 1900 E Street NW., Washington, DC 20415, Attention: Rachel Cooper or sent via electronic mail to rachel[email protected] . FOR FURTHER INFORMATION CONTACT: A copy of this ICR, with..., Office of Personnel Management, 1900 E Street NW., Washington, DC 20503, Attention: Rachel Cooper or sent...
77 FR 43808 - Advisory Committee and Species Working Group Technical Advisor Appointment
2012-07-26
... sent via email ( Rachel.O'[email protected] ). In the alternative, nominations may be sent via mail to Rachel O'Malley at NMFS, Office of International Affairs, Room 12622, 1315 East-West Highway, Silver Spring, MD 20910. FOR FURTHER INFORMATION CONTACT: Rachel O'Malley, Office of International Affairs, 301...
2013-12-04
... and suggestions to both: (1) Rachel Kastenberg, Office of Environmental Quality and Transboundary... number: DOS-2013-0022. FOR FURTHER INFORMATION CONTACT: Rachel Kastenberg, Telephone (202) 736-7111 or... Parties otherwise agree. If you would like to attend the public session, please notify Rachel Kastenberg...
78 FR 15796 - Data Collection Available for Public Comments
2013-03-12
... estimated burden and enhance the quality of the collections, to Rachel Newman Karton, Program Analyst..., Washington, DC 20416. FOR FURTHER INFORMATION CONTACT: Rachel Newman Karton, Program Analyst, 202-619-1618 rachel[email protected] Curtis B. Rich, Management Analyst, 202-205-7030 [email protected] . Title...
75 FR 6226 - Data Collection Available for Public Comments and Recommendations
2010-02-08
... minimize the estimated burden and enhance the quality of the collection, to Rachel Newman-Karton, Program... Floor, Washington, DC 20416. FOR FURTHER INFORMATION CONTACT: Rachel Newman-Karton, Office of Small Business Development Centers, 202-619-1816, rachel[email protected] . Curtis B. Rich, Management...
Kurjategijate moonded / Erkki Luuk
Luuk, Erkki, 1971-
2003-01-01
Hannibal Lecteri kuju Anthony Hopkinsi kehastuses Thomas Harrise romaanide alusel loodud triloogias "Voonakeste vaikimine" (Jonathan Demme, 1991), "Hannibal" (Ridley Scott, 2001) ja "Punane draakon" (Brett Ratner, 2002). Lisatud režissööride Jonathan Demme, Ridley Scotti ja Brett Ratneri filmograafiad lk. 102
The Ugly Side of The Beautiful Game: The War on Hooliganism Scrutinized
DEFF Research Database (Denmark)
Joern, Lise
2013-01-01
Brett Bebber, Violence and Racism in Football: Politics and Cultural Conflict in British Society, 1968–1998, London: Pickering & Chatto 2012......Brett Bebber, Violence and Racism in Football: Politics and Cultural Conflict in British Society, 1968–1998, London: Pickering & Chatto 2012...
Directory of Open Access Journals (Sweden)
Katz EG
2016-10-01
Full Text Available Eva G Katz,1 Brett Hauber,2 Srihari Gopal,3 Angie Fairchild,2 Amy Pugh,4 Rachel B Weinstein,3 Bennett S Levitan3 1Janssen Research & Development, LLC, Raritan, NJ, 2RTI Health Solutions, Research Triangle Park, NC, 3Janssen Research & Development, LLC, Titusville, NJ, 4The University of California, San Francisco (UCSF, CA, USA Purpose: To quantify clinical trial participants’ and investigators’ judgments with respect to the relative importance of efficacy and safety attributes of antipsychotic treatments for schizophrenia, and to assess the impact of formulation and adherence.Methods: Discrete-choice experiment surveys were completed by patients with schizophrenia and physician investigators participating in two phase-3 clinical trials of paliperidone palmitate 3-month long-acting injectable (LAI antipsychotic. Respondents were asked to choose between hypothetical antipsychotic profiles defined by efficacy, safety, and mode of administration. Data were analyzed using random-parameters logit and probit models.Results: Patients (N=214 and physicians (N=438 preferred complete improvement in positive symptoms (severe to none as the most important attribute, compared with improvement in any other attribute studied. Both respondents preferred 3-month and 1-month injectables to oral formulation (P<0.05, irrespective of prior adherence to oral antipsychotic treatment, with physicians showing greater preference for a 3-month over a 1-month LAI for nonadherent patients. Physicians were willing to accept treatments with reduced efficacy for patients with prior poor adherence. The maximum decrease in efficacy (95% confidence interval [CI] that physicians would accept for switching a patient from daily oral to 3-month injectable was as follows: adherent: 9.8% (95% CI: 7.2–12.4, 20% nonadherent: 25.4% (95% CI: 21.0–29.9, and 50% nonadherent: >30%. For patients, adherent: 10.1% (95% CI: 6.1–14.1, nonadherent: the change in efficacy studied was
Einstein, Albert
1967-01-01
Nello stato magmatico della fisica novecentesca Albert Einstein è il nucleo solido, la roccia stabilmente configurata che sta al centro. Di qui la sua posizione di "classico", come testimonia al più alto livello questa esposizione della teoria della relatività. Una teoria che ha segnato un vero mutamento di paradigma, non solo in campo scientifico: la potenza teorica dell'equivalenza relativistica massa-energia ha trovato, come sappiamo, la sua tragica verifica a Hiroshima, nel terrificante potenziale distruttivo della bomba atomica. Oggi, a oltre un secolo dalla originaria formulazione einsteiniana, è la comprensione della "relatività della relatività" che vuol essere perseguita. A introdurre il lettore a questa nuova dimensione provvede un'antologia di scritti di quegli autori che fondarono la scienza fisico-matematica classica e ne avviarono l'evoluzione in senso relativistico.
International Nuclear Information System (INIS)
Jumarie, Guy
2006-01-01
The (complex-valued) Brownian motion of order n is defined as the limit of a random walk on the complex roots of the unity. Real-valued fractional noises are obtained as fractional derivatives of the Gaussian white noise (or order two). Here one combines these two approaches and one considers the new class of fractional noises obtained as fractional derivative of the complex-valued Brownian motion of order n. The key of the approach is the relation between differential and fractional differential provided by the fractional Taylor's series of analytic function f(z+h)=E α (h α D z α ).f(z), where E α is the Mittag-Leffler function on the one hand, and the generalized Maruyama's notation, on the other hand. Some questions are revisited such as the definition of fractional Brownian motion as integral w.r.t. (dt) α , and the exponential growth equation driven by fractional Brownian motion, to which a new solution is proposed. As a first illustrative example of application, in mathematical finance, one proposes a new approach to the optimal management of a stochastic portfolio of fractional order via the Lagrange variational technique applied to the state moment dynamical equations. In the second example, one deals with non-random Lagrangian mechanics of fractional order. The last example proposes a new approach to fractional stochastic mechanics, and the solution so obtained gives rise to the question as to whether physical systems would not have their own internal random times
Breti Blue - ainus kodumaine hallitusega juust / Annely Allik
Allik, Annely
2006-01-01
Ettevõtte Luke Farmimeieri juht Aigar Brett juustutootmisest. Kommenteerib Eesti toiduainetööstuse Liidu juhataja Sirje Potisepp. Vt. samas: Niilo vahetab Bretiga sõira juustu vastu; Juustulett ootab uusi tooteid
Research Paper An exploratory study of psychological and ...
African Journals Online (AJOL)
Research Paper An exploratory study of psychological and developmental issues facing HIV and AIDS affected adolescents living in a residential care facility. Myrthe Van Vilsteren, Sadiyya Haffejee, Rabia Patel, Brett Bowman ...
... Fever Chapter 3 - Perspectives: Intradermal Rabies Preexposure Immunization Rabies Brett W. Petersen, Ryan M. Wallace, David R. ... animal. Box 3-04. World Health Organization, human rabies case definition Clinical case definition: a person presenting ...
Centers for Disease Control (CDC) Podcasts
2012-04-30
Dr. Brett Petersen, a medical officer at CDC, discusses rabies in captive deer. Created: 4/30/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID). Date Released: 4/30/2012.
Burdette, Shawn C.; Thornton, Brett F.
2018-02-01
Shawn C. Burdette and Brett F. Thornton explore how germanium developed from a missing element in Mendeleev's periodic table to an enabler for the information age, while retaining a nomenclature oddity.
6 Common Cancers - Breast Cancer
... Home Current Issue Past Issues 6 Common Cancers - Breast Cancer Past Issues / Spring 2007 Table of Contents For ... slow her down. Photo: AP Photo/Brett Flashnick Breast Cancer Breast cancer is a malignant (cancerous) growth that ...
Novaja vstretsha s Gannibalom Lekterom / Ilja Svensson
Svensson, Ilja
2002-01-01
USAs on valminud kolmas õudusfilm Anthony Hopkinsi mängitud Hannibal Lecteriga "Punane draakon" ("Red Dragon"). Thomas Harrise romaani on stsenaariumiks kirjutanud Ted Tally ja lavastanud Brett Ratner
Popkultuuri ikoon / Kristiina Davidjants
Davidjants, Kristiina, 1974-
2003-01-01
Inglise näitleja Anthony Hopkins on kolmandat korda Hannibal Lecteri rollis, seekord Brett Ratneri filmis "Punane draakon". Võrdlus Michael Manni 1986. a. filmiga "Manhunter", mis põhineb samale süzheele
Hannibal ründab jälle / Andres Laasik
Laasik, Andres, 1960-2016
2002-01-01
USAs on valminud kolmas õudusfilm Anthony Hopkinsi mängitud Hannibal Lecteriga "Punane draakon" ("Red Dragon"). Thomas Harrise romaani on stsenaariumiks kirjutanud Ted Tally ja lavastanud Brett Ratner
Arnoldussen, Stijn
2017-01-01
Borders, in the sense of modern geopolitical boundaries, have no bearing on prehistoric realities, yet they do affect archaeology as a discipline―particularly when one is committed to thinking, working, and writing on regions that transcend administrative limits, whether regional or national. While
Porras, R. C.; Hicks Pries, C.
2015-12-01
Globally, subsurface soils (>30 cm) represent an important reservoir of soil organic carbon (SOC). However, the vulnerability of this deep SOC and, in particular mineral-associated SOC, to warming, and its potential to amplify the effects of climate change is highly uncertain. To gain insight into the bio-accessibility and temperature sensitivity of mineral-associated organic C, we conducted a series of incubations using soils collected from three depths (0-10, 50-60, and 80-90 cm) under coniferous forest. The soils are moderately acidic (mean pH=6.5) sandy, mixed, mesic Ultic Haploxeralfs. To understand how mechanisms controlling SOC bio-accessibilty or temperature sensitivity differ with depth and with the properties of Fe-organo complexes (i.e.,degree of crystallinity, amount of reactive surface area, or surface saturation), we used a 13C labeled glucose substrate to prepare synthetic Fe-organo complexes spanning a range of crystallinity and mineral surface saturation. The synthetic Fe-organo complexes were then added to soil from three depths. The soils containing the 13C labeled Fe-organo adduct were incubated at two temperatures (ambient and +4°C) and respired 13CO2 was measured and used to estimate flux rates. Differences in measured 13CO2 fluxes as a function of depth, surface loading, and mineral properties are discussed in terms of their implications for the temperature sensitivity of mineral protected organic carbon in subsurface soils.
77 FR 39695 - Idaho Power Company; Notice of Availability of Draft Environmental Assessment
2012-07-05
...-102 and P-2061-086. For further information, contact Rachel Price by telephone at 202- 502-8907 or by email at Rachel[email protected] . Dated: June 26, 2012. Kimberly D. Bose, Secretary. [FR Doc. 2012-16367...
2013-12-06
...: Performance Review Board Leland L. Gardner, Chairman Rachel D. Campbell, Member Craig M. Keats, Member Lucille Marvin, Alternate Member Executive Resources Board Rachel D. Campbell, Chairman Lucille Marvin, Member Joseph H. Dettmar, Alternate Member These changes to the PRB and ERB membership are due to the departure...
African Tobacco Situational Analysis : Development Grants | CRDI ...
International Development Research Centre (IDRC) Digital Library (Canada)
Kitonyo, Rachel Syombua. Chargé(e) de projet. Kitonyo, Rachel. Institution. Institute for Legislative Affairs Trust. Pays d' institution. Ghana. Chargé(e) de projet. Pr Tetanye Ekoe. Chargé(e) de projet. Zakariaou Njoumemi. Chargé(e) de projet. Ekoe, Tetanye. Institution. University of Yaoundé I. Pays d' institution. Cameroon ...
String operator formalism and functional intergal in the holomorphic representation
International Nuclear Information System (INIS)
Losev, A.S.; Morozov, A.Yu.; Rislyj, A.A.; Shatashvili, S.L.
1989-01-01
Connection between the continual integral over open Riemann surfaces and the operator formalism on closed Riemann surfaces is discussed. States of the operator formalism are the holomorphic representation of the continual integral
Indian Academy of Sciences (India)
and others that their work was good-since it,was in conformity with his own calculations!), came out of Riemann's lecture trans- fixed with amazement and full of compliments. Most of the details of calculations in this lecture were only available in later papers of Riemann; these appeared late since Riemann was a man.
2016-08-01
Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC) En gi ne er R es ea rc h an d D ev el op m en t Ce nt er Brett A...Very-High-Strength Concrete (VHSC) and High-Strength High-Ductility Concrete (HSHDC) Brett A. Williams, Robert D. Moser, William F. Heard, Carol F...equipment and protocols for tests of both very-high-strength concrete (VHSC) and high- strength high-ductility concrete (HSHDC) to predict blast
Whiteread, Sullivan, Flavin : galeriiring : London / Jaan Elken
Elken, Jaan, 1954-
2006-01-01
Inglise skulptori ja installatsioonikunstniku Rachel Whiteread'i ja ameerika videokunstniku Catherine Sullivani näitustest Londonis Tate'i muuseumis. Ameerika valguskunstniku Dan Flavini (1933-1996) näitusest Haywardi galeriis
Radiology examination as a diagnostic aid in presentations with ...
African Journals Online (AJOL)
Radiology examination as a diagnostic aid in presentations with wide differential diagnoses: Case report of new Hodgkin's lymphoma on a background of poorly controlled HIV. Rachel Hubbard, Jalpa Kotecha, Thomas Nash, Yu Jin Lee, Nasir Khan, Farhat Kazmi ...
Randomised controlled trial of the efficacy of misoprostol used as a ...
African Journals Online (AJOL)
Randomised controlled trial of the efficacy of misoprostol used as a cervical ripening agent prior to termination of pregnancy in the first trimester. Eric T M de Jonge, Rachel Jewkes, Jonathan Levin, Helen Rees ...
Won, Rachel
2011-12-01
The combination of microwave photonics and optics has advanced many applications in defence, wireless communications, imaging and network infrastructure. Rachel Won talks to Jianping Yao from the University of Ottawa in Canada about the importance of this growing field.
Anti-yeast potential of some Annonaceae species from ...
African Journals Online (AJOL)
. Taffou Taffou, Jean Baptiste Hzounda Fokou, Elisabeth Zeuko'o Menkem, Lauve Rachel Tchokouaha Yamthe, Alvine Ngoutane Mfopa, Marguerite Simo Kamdem, Vincent Ngouana, Ide Flavie Kenfack Tsague, Fabrice Fekam Boyom ...
A comparative study of mutation screening of sarcomeric genes ...
African Journals Online (AJOL)
, TNNT2) using single gene approach versus targeted gene panel next generation sequencing in a cohort of HCM patients in Egypt. Heba Sh. Kassem, Roddy Walsh, Paul J. Barton, Besra S. Abdelghany, Remon S. Azer, Rachel Buchan, ...
76 FR 68500 - Performance Review Board Appointments
2011-11-04
...-Bartels, Leslie Ishee, Mary Katherine Iudicello, Fay Jackson, Andrew Jacobson, Rachel Keable, Edward..., Bernard More, Robert Mulhern, Thomas Nedd, Michael O'Dell, Margaret Owens, Glenda Palma, Juan Payne...
75 FR 68375 - Performance Review Board Appointments
2010-11-05
... C. Hildebrandt, Betsy J. Iudicello, Fay S. Jackson, J. Andrew Jacobson, Rachel L. Keable, Edward T..., Donald E. Jr. Malam, Pamela R. Mazer, Bernard J. Moss, Adrianne L. More, Robert S. Nedd, Michael D. O...
The Discourse of "Environmentalist Hysteria."
Killingsworth, M. Jimmie; Palmer, Jacqueline S.
1995-01-01
Fleshes out a model of hysterical discourse, and applies it to an analysis of the charges and countercharges of "environmentalist hysteria." Gives special attention to the book that drew the earliest accusations of hysteria, Rachel Carson's "Silent Spring." (SR)
Anatomy of a Cancer Treatment Scam
Full Text Available ... of Policy Planning Regional Offices Office of Administrative Law Judges Office of Public Affairs Office of the ... Robocalls: Humanity Strikes Back DetectaRobo Zapping Rachel Enforcement Cases and Proceedings Case Document Search Refunds Commission Decision ...
2010-04-14
...-No. 1), 395 E Street, SW., Washington, DC 20423-0001. FOR FURTHER INFORMATION CONTACT: Joseph Dettmar.... By the Board, Rachel D. Campbell, Director, Office of Proceedings. Jeffrey Herzig, Clearance Clerk...
2010-11-05
..., Inc. at the specified station in Chester County. FOR FURTHER INFORMATION CONTACT: Joseph H. Dettmar..., Rachel D. Campbell, Director, Office of Proceedings. Andrea Pope-Matheson, Clearance Clerk. [FR Doc. 2010...
76 FR 35070 - Canexus Chemicals Canada L.P. v. BNSF Railway Company
2011-06-15
... FURTHER INFORMATION, CONTACT: Joseph Dettmar, (202) 245-0395. Assistance for the hearing impaired is... conservation of energy resources. Decided: June 10, 2011. By the Board. Rachel D. Campbell, Director, Office of...
2012-12-21
... headroom) to enable IR to continue serving the shipper, Joseph Behr & Sons, Inc. (Behr). These trackage..., Rachel D. Campbell, Director, Office of Proceedings. Jeffrey Herzig, Clearance Clerk. [FR Doc. 2012-30817...
2013-07-10
... requires all rail traffic to the warehouse ``to immediately cease and desist.'' \\2\\ \\1\\ Pet., Ex. B at 2...: July 3, 2013. By the Board, Rachel D. Campbell, Director, Office of Proceedings. Jeffrey Herzig...
Evolution of microbial pathogens
National Research Council Canada - National Science Library
DiRita, Victor J; Seifert, H. Steven
2006-01-01
... A. Hogan vvi ■ CONTENTS 8. Evolution of Pathogens in Soil Rachel Muir and Man-Wah Tan / 131 9. Experimental Models of Symbiotic Host-Microbial Relationships: Understanding the Underpinnings of ...
75 FR 35877 - Senior Executive Service Performance Review Board
2010-06-23
... of the senior executive. The persons named below have been selected to serve on STB's PRB: Leland L..., Director, Office of Public Assistance, Governmental Affairs, and Enforcement; Rachel D. Campbell, Director...
78 FR 50141 - Illinois Central Railroad Company-Trackage Rights Exemption-BNSF Railway Company
2013-08-16
...., Washington, DC 20423-0001. In addition, a copy of each pleading must be served on Audrey L. Brodrick..., Rachel D. Campbell, Director, Office of Proceedings. Jeffrey Herzig, Clearance Clerk. [FR Doc. 2013-19937...
76 FR 46896 - Senior Executive Service Performance Review Board
2011-08-03
... of the senior executive. The persons named below have been selected to serve on STB's PRB. Leland L. Gardner, Director, Office of the Managing Director; Rachel D. Campbell, Director, Office of Proceedings...
U.S. Environmental Protection Agency — The Cumulative Impacts (CI) screening method is jointly being developed by Manuel Pastor, Jim Sadd (Occidental College), and Rachel Morello-Frosch (UC Berkeley) ....
Moodne aeg käib alla / Valner Valme
Valme, Valner, 1970-
2008-01-01
Arvustus: Beigbeder, Frédéric. Armastus kestab kolm aastat : romaan / prantsuse keelest tõlkinud Anti Saar. Tallinn : Varrak, 2008 ; Cusk, Rachel. Arlington Park / tõlkinud Kersti Unt. Tallinn : Varrak, 2007
Beyond Collier's Bottom Billion Randy Spence
International Development Research Centre (IDRC) Digital Library (Canada)
Design & Layout: Andrea Puppo, Carolina Robino, and Rachel Ziemba 2006. Formatting and .... development, moving beyond manufactured exports. ..... production and export have been promoted heavily in many BB countries and by major.
The influence of peers and other significant persons on sexuality ...
African Journals Online (AJOL)
use among young adults in northern Tanzania. Bernard Njau, Sabina Mtweve, Longin Barongo, Rachel Manongi, Juliet Chugulu, Marcelina Msuya, Stella Mwampeta, Bertha Kiwale, Joseph Lekule, Hector Jalipa ...
V zashtshitu zdanija narvskoi Birzhi / Jüri Kuuskemaa
Kuuskemaa, Jüri, 1942-
2006-01-01
Eesti Muinsuskaitse Seltsi juhatuse avaldus seoses Tartu Ülikooli Narva kolledzhi projektiga. Sisaldab retsensiooni projektile "Vihm" (autorid Katrin Koov, Indrek Peil, Siiri Vallner), mis on inspireeritud inglise skulptori Rachel Whitereadi loomingust
African Journals Online (AJOL)
Items 51 - 100 of 247 ... Vol 29, No 1 (2016), Insights from Hans Achterhuis Applied to the Violence on LGBT Communities in Uganda, Abstract. Jaco Beyers. Vol 28, No 1 (2015), Interpreting Luguru Religious Practice through Colonialist Eyes: Child Sacrifice and East African Dance in Brett Young's The Crescent Moon ...
2012-06-08
Denzin and Lincoln propose that “Qualitative research is a situated activity that locates the observer in the world. It consists of a set of......Publications, 2003. Davies, Martin Brett. Doing a Successful Research Project. New York: Palgrave Macmillan, 2007. Denzin , Norman K., and Yvonna S
Nutritive potentials and utilization of garden snail (Limicolaria aurora ...
African Journals Online (AJOL)
AJB SERVER
2006-10-16
Oct 16, 2006 ... The possibility of using garden snail (Limicolaria aurora) meat meal as a protein source in fish feeds was tested in ... garden snail meat meal was used to replace fish meal at 0%, (control diet), 25, 50, 75 and 100% inclusion ..... Randall DJ, Brett JR (eds) Fish Physiology, Academic Press, NY 8: 279-352,.
78 FR 23960 - Sunshine Act Meetings
2013-04-23
...' Conference Room, 11555 Rockville Pike, Rockville, Maryland. STATUS: Public and Closed. Week of April 22, 2013... Meeting) (Contact: Brett Rini, 301-251-7615). This meeting will be webcast live at the Web address--www.nrc.gov. 2:30 p.m. Discussion of Management and Personnel Issues (Closed--Ex. 2 and 6). Tuesday April...
78 FR 21171 - Sunshine Act Meetings
2013-04-09
...: Commissioners' Conference Room, 11555 Rockville Pike, Rockville, Maryland. STATUS: Public and Closed. Week of... Meeting) (Contact: Brett Rini, 301-251-7615) This meeting will be webcast live at the Web address--www.nrc.gov. 2:30 p.m. Discussion of Management and Personnel Issues (Closed-- Ex. 2 and 6) Tuesday, April 23...
78 FR 18376 - Sunshine Act Meetings
2013-03-26
...: Commissioners' Conference Room, 11555 Rockville Pike, Rockville, Maryland. STATUS: Public and Closed. Week of...-0223). This meeting will be webcast live at the Web address--www.nrc.gov. Week of April 8, 2013...) (Contact: Brett Rini, 301-251-7615). This meeting will be webcast live at the Web address--www.nrc.gov. 2...
Thornton, Brett F.; Burdette, Shawn C.
2014-07-01
Alfred Nobel's eponymous element, nobelium, was 'first' discovered either in the 1950s or 1960s, in the USSR, Sweden or the USA. Brett F. Thornton and Shawn C. Burdette delve into the ensuing decades of internecine strife over the discovery of element 102.
Teater. Muusika. Nyyd / Anneli Remme
Remme, Anneli, 1968-
2005-01-01
ERSO ja NYYD Ensemble'i ühiskontserdil esitatud Brett Deani "Kontserdist vioolale ja orkestrile" ja teosest "Game Over", Küberstuudio etendusest "Lend-ajad", hispaania laulja Fatima Miranda kontsertetendusest "Diapassion", Michel van der Aa kammerooperist "One" rahvusvahelise uue muusika festivali "NYYD 2005" raames
2012-03-28
... Intertek USA, Inc., as a Commercial Gauger and Laboratory AGENCY: U.S. Customs and Border Protection... commercial gauger and laboratory. SUMMARY: Notice is hereby given that, pursuant to 19 CFR 151.12 and 19 CFR 151.13, Intertek Caleb Brett, 6050 Egret Court, Benicia, CA 94510, has been approved to gauge and...
de Goede, M.; Burgess, J.P.
2010-01-01
1. Introduction J. Peter Burgess Part 1: New Security Concepts 2. Civilizational Security Brett Bowden 3. Risk Oliver Kessler 4. Small Arms Keith Krause 5. Critical Human Security Taylor Owen 6. Critical Geopolitics Simon Dalby Part 2: New Security Subjects 7. Biopolitics Michael Dillon 8. Gendered
Bagatellid : Maailm / Nele-Eva Steinfeld
Steinfeld, Nele-Eva
2009-01-01
Muusikasõnumeid maailmast: Gil Shaham pälvis Avery Fischer Prize'i. Riccardo Muti keeldus esinemisest prints Charlesi juubelil. Maailma esiorkester on Amsterdami Royal Concertgebouw' orkester. Suri dirigent Richard Hickox. Gennadi Roždestvenski katkestas kontserdisarja. Brett Dean pälvis Grawemeyeri auhinna. Mirjam Tally pälvis Rootsi tähtsaima helikunstipreemia
Functional Foods as Differentiated Products: the Italian Yogurt Market
Bonanno, A.
2013-01-01
In spite of the growing consumers' interest for functional foods, the knowledge regarding the demand for these products and their profitability is limited. Adapting the LA/AIDS (Linear Approximated–Almost Ideal Demand System) model by means of Pinkse, Slade and Brett's distance metric method (2002),
Terrestrial Rabies and Human Postexposure Prophylaxis, New York, USA
Centers for Disease Control (CDC) Podcasts
This podcast describes a 10-year study of the use of postexposure prophylaxis (PEP) for rabies in New York State. CDC's Dr. Brett Petersen discusses the prevalence of rabies in the United States and how the study lends support to recent changes in the recommended PEP protocol.
Human and animal studies: portals into the whole body and whole population response
Human and animal studies: portals into the whole body and whole population response Michael C. Madden1 and Brett Winters21US Environmental Protection Agency and 2University of North Carolina Human Studies Facility, Chapel Hill, North Carolina, USA Studies involving collection and...
Paaver, Ene, 1963-
2001-01-01
Rahvusvaheline festival "Talveöö unenägu" Tallinna Linnateatris 28.- 30. dets. Lavastused : "K. I. Kuritööst" (lav. Kama Ginkas, Moskva Noorsooteater), "Gargantua ja Pantagruel" (lav. Stanislavas Rubinovas, Kaunase Noorsooteater), "Preili Pollinger" (lav. Edith Koerber, Saksa Tri-Bühne), "Rusudekorjajad" (lav. Nika Brettschneider, Viini Brett Theater)
DVD-d. Nacho Libre. Tipptund 3 / Andres Laasik
Laasik, Andres, 1960-2016
2008-01-01
Lühiarvustused DVD-l levitatavatest filmidest "Nacho Libre" : režissöör Jared Hess : Ameerika Ühendriigid 2006 ja "Tipptund 3" (Rush Hour 3") : režissöör Brett Ratner : Ameerika Ühendriigid 2007
Having Autism as a Student at Briarcliffe College
Brazier, Jamie
2013-01-01
His name is Brett Schmidt, and he is a college student with Autism. His greatest challenge of having autism is communication. When he first applied to Briarcliffe College, he was given an e-mail address to the Campus Portal. He had to train himself to look at the portal frequently for communication and information. On the start of the semester, he…
Karibskaja ekzotika i zapozdalõi zvonok / Jevgeni Levik
Levik, Jevgeni
2005-01-01
Mängufilm "Pärast päikeseloojangut" ("After the Sunset") : režissöör Brett Ratner : USA 2004 ja õudusfilm "Ring 2" ("The Ring Two") : režissöör Hideo Nakata : Ameerika Ühendriigid - Jaapan 2005
Meiessaar, Maris
2009-01-01
PÖff-i filmidest - "Merehädaline kuul" (rež. Lee Hey-Jun; Lõuna-Korea), "Nanjing: Elu ja surma linn" (rež. Lu Chuan; Hiina), "Kuu" (rež. Duncan Jones; Suurbritannia), "Rip! A Remix Manifesto" (rež. Brett Gaylor; Kanada)
The New Woman in "The Sun Also Rises"
Yu, Xiaoping
2010-01-01
Hemingway is a famous American writer and a spokesman of the Lost Generation. His life attitude of the characters in the novels influenced the whole world. His first masterpiece "The Sun Also Rises" contributes a lot to the rise of feminism and make the world began to be familiar with a term: The New Woman through the portrayal of Brett.…
Ütle, mis on sinu garderoobis, ja ma ütlen, kes sa oled / Sigrid Saarep
Saarep, Sigrid
1999-01-01
Suurbritannia moe- ja fotograafianäitus 1960ndatest tänapäevani "Look at me" Tallinna Kunstihoones 5. dets.-ni. Kuraatorid Val Williams, Brett Rogers. Olulise osana sisaldub näitusel veel briti 1960.-90. aastate noortekultuuri, eriti noorte subkultuuri peegeldusi. Pildistatud on modisid, skinheade, punkareid (neist pikemalt), uusromantikuid ja inimesi tänavalt.
Inglise mood ja foto Kunstihoones
1999-01-01
5. nov.-st Tallinna Kunstihoones näitus "Look at me", Suurbritannia mood ja fotograafia 1960ndatest tänapäevani. Kuraatorid Val Willams, Brett Rogers. Osalejaid. 6. XI samas eesti moekunstnike britiaineline moeshow. Osalevad Anu Lensment, Eve Hanson, Marit Ahven, Jaanus Vahtra, Marju Tammik, Anu Samarüütel
Effective Stringy Description of Schwarzschild Black Holes
Krasnov , Kirill; Solodukhin , Sergey N.
2004-01-01
We start by pointing out that certain Riemann surfaces appear rather naturally in the context of wave equations in the black hole background. For a given black hole there are two closely related surfaces. One is the Riemann surface of complexified ``tortoise'' coordinate. The other Riemann surface appears when the radial wave equation is interpreted as the Fuchsian differential equation. We study these surfaces in detail for the BTZ and Schwarzschild black holes in four and higher dimensions....
A Brief Survey of Higgs Bundles
Zúñiga-Rojas, Ronald Alberto
2018-01-01
Considering a compact Riemann surface of genus greater than two, a Higgs~bundle is a pair composed of a holomorphic bundle over the Riemann surface, joint with an auxiliar vector field, so-called Higgs field. This theory started around thirty years ago, with Hitchin's work, when he reduced the self-duality equations from dimension four to dimension two, and so, studied those equations over Riemann surfaces. Hitchin baptized those fields as "Higgs fields" beacuse in the context of physics and ...
Numerical method for two-phase flow discontinuity propagation calculation
International Nuclear Information System (INIS)
Toumi, I.; Raymond, P.
1989-01-01
In this paper, we present a class of numerical shock-capturing schemes for hyperbolic systems of conservation laws modelling two-phase flow. First, we solve the Riemann problem for a two-phase flow with unequal velocities. Then, we construct two approximate Riemann solvers: an one intermediate-state Riemann solver and a generalized Roe's approximate Riemann solver. We give some numerical results for one-dimensional shock-tube problems and for a standard two-phase flow heat addition problem involving two-phase flow instabilities
On vanishing of vacuum energy for superstrings
International Nuclear Information System (INIS)
Morozov, A.; Perelomov, A.
1986-01-01
Hypothesis, concerning the structure of formulae for vacuum diagrams in the first-quantized superstring theory is proposed. The analytical measure in the integration over moduli space is proportional to the sum over spin structures on Riemann surfaces and vanishes because of the Riemann identities for Θ-constants
Cavalieri Integration | Ackermann | Quaestiones Mathematicae
African Journals Online (AJOL)
We also present two methods of evaluating a Cavalieri integral by first transforming it to either an equivalent Riemann or Riemann-Stieltjes integral by using special transformation functions h(x) and its inverse g(x), respectively. Interestingly enough it is often very difficult to find the transformation function h(x), whereas it is ...
Some remarks on geodesics in gauge groups and harmonic maps
International Nuclear Information System (INIS)
Valli, G.
1987-08-01
The following topics are discussed: Euler's equations for geodesics in the gauge groups and in gauge orbits of connections, conserved quantities and moment map, existence and uniqueness of solutions for the Cauchy problem, stationary solutions and harmonic bundles, harmonic gauges on Riemann surfaces and Lax pairs, low geodesics in gauge groups over Riemann surfaces produce, by Hodge decomposition, paths of holomorphic differentials. 19 refs
Interactions of Delta Shock Waves for Zero-Pressure Gas Dynamics with Energy Conservation Law
Wei Cai; Yanyan Zhang
2016-01-01
We study the interactions of delta shock waves and vacuum states for the system of conservation laws of mass, momentum, and energy in zero-pressure gas dynamics. The Riemann problems with initial data of three piecewise constant states are solved case by case, and four different configurations of Riemann solutions are constructed. Furthermore, the numerical simulations completely coinciding with theoretical analysis are shown.
Indian Academy of Sciences (India)
Riemann has written on shock waves, electrodynamics and even on the mechanics of the ear! But the main impact of. Riemann's work ... This physical insight led him to the idea that the gravitational field can be described by geometry. Luckily ...
Directory of Open Access Journals (Sweden)
Ghulam Farid
2017-10-01
Full Text Available The aim of this paper is to obtain some more general fractional integral inequalities of Fejer Hadamard type for p-convex functions via Riemann-Liouville k-fractional integrals. Also in particular fractional inequalities for p-convex functions via Riemann-Liouville fractional integrals have been deduced.
A General Expression for the Quintic Lovelock Tensor
Briggs, C. C.
1996-01-01
A general expression is given for the quintic Lovelock tensor as well as for the coefficient of the quintic Lovelock Lagrangian in terms of the Riemann-Christoffel and Ricci curvature tensors and the Riemann curvature scalar for n-dimensional differentiable manifolds having a general linear connection.
Briggs, C C
2000-01-01
An overview is given of various occurrences of general expressions for the coefficients of Lovelock Lagrangians and for Lovelock tensors from the 0th to the 5th order in curvature in terms of the Riemann-Christoffel and Ricci curvature tensors and the Riemann curvature scalar for n-dimensional differentiable manifolds having a general linear connection.
Siegel, Edward Carl-Ludwig; Young, Frederic; Wignall, Janis
2013-04-01
SEPHIROT: Siegel[http://fqxi.org/community/forum/topic/1553]: Ten-[0->9]-Digits; Average Log-Law SCALE-Invariance; Utter-Simplicity: ``Complexity'' (vs. ``Complicatedness''); Zipf-law/Hyperbolicity/ Inevitability SCENARIO AUTOMATICALLY CREATES & EVOLVES a UNIVERSE: inflation, a big-bang, bosons(E)->Mellin-(c2)-tranform->fermions(m), hidden-dark-energy(HDE), hidden-dark-matter (HDM), cosmic-microwave-background(CMB), supersymmetry(SUSY), PURPOSELY NO: theories,models,mechanisms,processes, parameters,assumptions,WHATSOEVER: It's a ``Jack-in-the-Box'' Universe!!!: ONLY VIA: Newcomb [Am.J.Math.4(1),39(1881)]QUANTUM-discovery!!!-Benford-Siegel-Antonoff[AMS.Joint-Mtg.(02)-Abs.#973-60-124!!!] inversion to ONLY BEQS with d=0 BEC: ``Digit-Physics''!; Log fixed-point invariance(s): [base=units=SCALE] of digits classic (not classical!) average [CAUSING] log statistical-correlations =log(1+1/d), with physics-crucial d=0 BEC singularity/pole, permits SEPHIROT!!!: ``digits are quanta are bosons because bosons are and always were digits!!!'': Digits = Bosons with d=0 BEC(!!!) & expansion to Zipf-law Hyperbolicity INEVITABILITY CMB!
Book Review: The X-Ways Forensics Practitioner's Guide
Directory of Open Access Journals (Sweden)
Linda Lau
2014-09-01
Full Text Available Shavers, B., and Zimmerman, E. (2013. The X-Ways Forensics Practitioner's Guide. Waltham, MA: Syngress, 242 pages. ISBN: 978-0-12-411605-4. Print: US $50.90. Includes exercises, case studies, references, and index. Reviewed by Linda K. Lau, Longwood UniversityBrett Shavers is a former law enforcement officer, a digital forensics examiner, an adjunct instructor, and a frequent speaker at many conferences. After writing his first book, titled Placing the Suspect Behind the Keyboard: Using Digital Forensics and Investigative Techniques to Identify Cybercrime Suspects, he co-wrote his 2nd book with Eric Zimmerman and Jimmy Weg, who is a knowledgeable technical editor. Both Brett and Eric are experts in cyber forensics, with many years of law enforcement experience at both the state and federal levels.
2016-06-01
employs the in- variance of the Maxwell equations under coordinate transformations to convert the free- space wave solutions in a coordinate... ENERGY WEAPON DEFENSE by Jacob D. Thompson June 2016 Thesis Co-Advisors: James Luscombe Brett Borden Approved for public release; distribution is...2014 to 06-17-2016 4. TITLE AND SUBTITLE NONLINEAR EFFECTS IN TRANSFORMATION OPTICS-BASED METAMATE- RIAL SHIELDS FOR COUNTER DIRECTED ENERGY WEAPON
Naval Surface Forces Real-Time Reutilization Asset Management Warehouses: A Cost-Benefit Analysis
2008-12-01
shared their valuable insights. And finally, to our advisors Dr . Ken Euske and CDR Brett Wagner who kept us on track throughout the project. Nick could...of $206,368,657. SURFOR’s East and West Coast warehouses accounted for $146,975,108 of the list value. The team identified potential cost...obligating the funds. A relatively simple cost benefit analysis of the reprogramming costs versus the cost savings would justify the expense. In the
Negotiation in the New Strategic Environment: Lessons From Iraq
2007-08-01
Andrew Terrell , Reconstructing Iraq: Insights, Challenges, and Missions for Military Forces in a Post- Conflict Scenario, Carlisle Barracks, PA...Negotiation, Ann Arbor, MI: University of Michigan Press, 2000, pp. 271-273 (hereafter Zartman and Rubin, Symmetry and Assymmetry). 80. As discussed...122. See Mnookin, Beyond Winning, pp. 28-31. 123. See Anne L. Lytle, Jeanne M. Brett, and Debra L. Shapiro, “The Strategic Use of Interests, Rights
Cyberforce 2025: Crafting a Selection Program for Tomorrow’s Cyber Warriors
2013-02-14
One of the more current and commonly used adult IQ tests is the Wechsler Adult Intelligence Scale – fourth edition (WAIS- IV), which currently...LeMay Center for Doctrine Development and Education, 2011. David J. Kay, Terry J. Pudas, and Brett Young. Preparing the Pipeline: The...34 May/June 1973: 30-34. Times, The New York. Foreign Intelligence Surveillance Act (FISA). New York, September 13, 2012. Trollman, Capt David
Sadosky, Alesia; Parsons,Bruce; Schaefer,Caroline; Mann,Rachael; Daniel,Shoshana; Nalamachu,Srinivas; Stacey,Brett R; Nieshoff,Edward C; Tuchman,Michael; Anschel,Alan
2013-01-01
Bruce Parsons,1 Caroline Schaefer,2 Rachael Mann,3 Alesia Sadosky,1 Shoshana Daniel,4 Srinivas Nalamachu,5 Brett R Stacey,6 Edward C Nieshoff,7 Michael Tuchman,8 Alan Anschel91Pfizer, Inc, New York, NY, USA; 2Covance Market Access Services, Inc, Gaithersburg, MD, USA; 3Covance Market Access Services, Inc, San Diego, CA, USA; 4Covance Market Access Services, Inc, Conshohocken, PA, USA; 5International Clinical Research Institute, Overland Park, KS, USA; 6Oregon Health and Science University, Po...
Terrestrial Rabies and Human Postexposure Prophylaxis, New York, USA
Centers for Disease Control (CDC) Podcasts
2010-03-15
This podcast describes a 10-year study of the use of postexposure prophylaxis (PEP) for rabies in New York State. CDC's Dr. Brett Petersen discusses the prevalence of rabies in the United States and how the study lends support to recent changes in the recommended PEP protocol. Created: 3/15/2010 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID). Date Released: 4/15/2010.
DEFF Research Database (Denmark)
Stewart, Jon Bartley
2007-01-01
This volume, the third in the series, contains the proceedings of the conference 'Law before Gratian' and covers a wide range of topics from individual and local studies to broader reflections on the status and function of law in medieval European societies before the scholastic legal 'revoluti...... to this volume are Maurizio Lupoi (Genova), Alic Rio (Oxford), Charles Radding (Michigan), Martin Brett (Cambridge), Bruce Brasington (West Texas A&M) and Dominique Bauer (Ghent)....
Oliveras, Clara; Fortea, Adriana; Espinosa, Laura; Barrio, Pablo; Lligoña, Anna; Balcells-Olivero, Mercè
2018-04-15
Benzodiazepines (BZDs) are central nervous system (CNS) depressants which are widely used to treat insomnia and anxiety, despite having long-term adverse side effects. (Fortea González, Oriolo, Balcells Oliveró, Sánchez Del Valle & Castellvi, 2017). As with alcohol, continued use can lead to tolerance and dependence phenomena. Discontinuation in such cases can produce abstinence symptoms such as tremors, anxiety, seizures and, occasionally, death (Brett y Murnion, 2015).
Can eye-tracking technology improve situational awareness in paramedic clinical education?
Williams, Brett; Cooper,Simon; Quested,Andrew
2013-01-01
Brett Williams,1 Andrew Quested,1 Simon Cooper21Department of Community Emergency Health and Paramedic Practice, 2School of Nursing and Midwifery, Berwick, Monash University, Frankston, VIC, AustraliaAbstract: Human factors play a significant part in clinical error. Situational awareness (SA) means being aware of one's surroundings, comprehending the present situation, and being able to predict outcomes. It is a key human skill that, when properly applied, is associated with reducing ...
Precipitating the Decline of Al-Shabaab: A Case Study in Leadership Decapitation
2015-12-01
disbanding leadership councils, and relying on an autocratic leadership style .150 Militarily, Al-Shabaab went back to its roots...Godane’s autocratic leadership methods severely degraded the strength and influence of Al-Shabaab, and would likely have continued to isolate the group...SHABAAB: A CASE STUDY IN LEADERSHIP DECAPITATION by Brett M. Butler December 2015 Thesis Advisor: Bradley Jay Strawser Second Reader: Anna Simons
Defense Energy Support Center Fact Book, Fiscal Year 2008, Thirty-First Edition
2009-01-01
discussions were also held with Parque Industrial Maritimo De Panama SA (DFSP contractor), ITS Caleb- Brett (DESC Laboratory Services Contractor) and GP...its customers and the energy industry by fostering and maintaining business alliances around the world. To better serve those customers, as well as to...and all of DESC to accomplish business process reengineering as needed to take full advantage of the SAP industry solutions while ensuring continual
Evaluating three proposals for testing independence in non linear spatial processes
López Hernández, Fernando Antonio; Mate Sánchez-Val, María Luz; Artal Tur, Andrés
2013-01-01
[ENG]This paper evaluates the behaviour of different families of tests when checking for spatial independence in the presence of nonlinearities. To reach this goal, we select three representative proposals. The usual parametric tests of I-Moran, the nonparametric proposal of Brett and Pinkse (1997), and the semiparametric Scan test. In order to study how they perform, we simulate different nonlinear spatial structures by Monte Carlo methods, hence conducting empirical tests on ...
High pressure inactivation of Brettanomyces bruxellensis in red wine.
van Wyk, Sanelle; Silva, Filipa V M
2017-05-01
Brettanomyces bruxellensis ("Brett") is a major spoilage concern for the wine industry worldwide, leading to undesirable sensory properties. Sulphur dioxide, is currently the preferred method for wine preservation. However, due to its negative effects on consumers, the use of new alternative non-thermal technologies are increasingly being investigated. The aim of this study was to determine and model the effect of high pressure processing (HPP) conditions and yeast strain on the inactivation of "Brett" in Cabernet Sauvignon wine. Processing at 200 MPa for 3 min resulted in 5.8 log reductions. However higher pressure is recommended to achieve high throughput in the wine industry, for example >6.0 log reductions were achieved after 400 MPa for 5 s. The inactivation of B. bruxellensis is pressure and time dependent, with increased treatment time and pressure leading to increased yeast inactivation. It was also found that yeast strain had a significant effect on HPP inactivation, with AWRI 1499 being the most resistant strain. The Weibull model successfully described the HPP "Brett" inactivation. HPP is a viable alternative for the inactivation of B. bruxellensis in wine, with the potential to reduce the industry's reliance on sulphur dioxide. Copyright © 2016 Elsevier Ltd. All rights reserved.
Generalized Roe's numerical scheme for a two-fluid model
International Nuclear Information System (INIS)
Toumi, I.; Raymond, P.
1993-01-01
This paper is devoted to a mathematical and numerical study of a six equation two-fluid model. We will prove that the model is strictly hyperbolic due to the inclusion of the virtual mass force term in the phasic momentum equations. The two-fluid model is naturally written under a nonconservative form. To solve the nonlinear Riemann problem for this nonconservative hyperbolic system, a generalized Roe's approximate Riemann solver, is used, based on a linearization of the nonconservative terms. A Godunov type numerical scheme is built, using this approximate Riemann solver. 10 refs., 5 figs,
Hearing the music of the primes: auditory complementarity and the siren song of zeta
International Nuclear Information System (INIS)
Berry, M V
2012-01-01
A counting function for the primes can be rendered as a sound signal whose harmonies, spanning the gamut of musical notes, are the Riemann zeros. But the individual primes cannot be discriminated as singularities in this ‘music’, because the intervals between them are too short. Conversely, if the prime singularities are detected as a series of clicks, the Riemann zeros correspond to frequencies too low to be heard. The sound generated by the Riemann zeta function itself is very different: a rising siren howl, which can be understood in detail from the Riemann–Siegel formula. (fast track communication)
2010-11-12
... certified that: (1) No local traffic has moved over the line for at least 2 years; (2) there is no overhead traffic on the line to be rerouted; (3) no formal complaint filed by a user of rail service on the line... our website at http://www.stb.dot.gov . Decided: November 4, 2010. By the Board, Rachel D. Campbell...
'Living History'--An Opportunity for Living Science
Linfield, Rachel
2018-01-01
Rachel Linfield describes a favorite annual school visit to Wimpole Hall where her year 4 and 5 students (ages 8-10) took part in a living history project. Each summer, dressed as servants from the Georgian era, students would spend the day as apprentice housemaids and butlers. Although the trips to Wimpole Hall were invaluable for developing a…
African Journals Online (AJOL)
Radiology examination as a diagnostic aid in presentations with wide differential diagnoses: Case report of new Hodgkin's lymphoma on a background of poorly controlled HIV · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Rachel Hubbard, Jalpa Kotecha, Thomas ...
Indigenous Healing Practices and Self-Medication amongst ...
African Journals Online (AJOL)
Indigenous Healing Practices and Self-Medication amongst Pregnant Women in Cape Town, South Africa. Naeemah Abrahams, Rachel Jewkes, Zodumo Mvo. Abstract. This study was conducted in and around Cape Town, South Africa, at two primary obstetric facilities and in the antenatal clinics of two secondary hospitals.
Viral load, CD4+ T-lymphocyte counts and antibody titres in HIV-1 ...
African Journals Online (AJOL)
Viral load, CD4+ T-lymphocyte counts and antibody titres in HIV-1 infected untreated children in Kenya; implication for immunodeficiency and AIDS progression. Washingtone Ochieng, Dorington Ogoyi, Francis J Mulaa, Simon Ogola, Rachel Musoke, Moses G Otsyula ...
Journal of Child and Adolescent Mental Health - Vol 28, No 1 (2016)
African Journals Online (AJOL)
A first-level evaluation of a family intervention for adolescent social, emotional and behavioural difficulties in Child and Adolescent Mental Health Services · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Ciara Wynne, Caoimhe Doyle, Rachel Kenny, Eileen Brosnan, John Sharry ...
Management of Perforated Mooren's Ulcer with a Rotational Scleral ...
African Journals Online (AJOL)
A case of bilateral Mooren's ulcer with corneal melting and uveal prolapse in the left eye (LE) involving 1½ h was managed with a scleral rotational autograft at the Rachel Eye Center, Abuja. The patient was a 75‑year‑old female retiree with concomitant rheumatoid arthritis involving the knee and metacarpophalangeal joints ...
African Journals Online (AJOL)
Subscriptions Contact. Rachel Rege Kenya Agricultural Research Institute, P O Box 57811, Nairobi, KENYA Email: rrege@kari.org. East Africa Kssh 4000; Sterling 40; USA $62; including postage by surface mail. Postage by air mail can be arranged at cost on request. Payments to be made to the Editor, East African ...
African Journals Online (AJOL)
Kawuma, Rachel. Vol 13, No 2 (2014) - Articles 'Children will always be children': Exploring perceptions and experiences of HIV-positive children who may not take their treatment and why they may not tell. Abstract. ISSN: 1608-5906. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians ...
Behaviour of the homologues of Rf and Db in complexing media
International Nuclear Information System (INIS)
Trubert, D.; Monroy Guzman, F.; Hussonnois, M.; Brillard, L.; Le Naour, C.; Servajean, V.; Constantinescu, O.; Constantinescu, M.; Ardisson, G.; Barci, V.; Weiss, B.
1999-01-01
In order to study the chemical behaviour of the trans-actinide elements, the chemical properties of their most probable homologues have been investigated by ion exchange methods in various complexing media. A new chromatographic method allowing the determination of distribution coefficients in the case o short-lived isotopes has been developed and successfully tested with the RACHEL device. (authors)
In vitro and in vivo antiplasmodial activity of extracts from Polyalthia ...
African Journals Online (AJOL)
In vitro and in vivo antiplasmodial activity of extracts from Polyalthia suaveolens, Uvaria angolensis and Monodora tenuifolia (Annonaceae). Alvine Ngoutane Mfopa, Cedric Derick Jiatsa Mbouna, Lauve Rachel Yamthe Tchokouaha, Marthe Aimée Tchuenmegne Tchuente, Rufin Marie Toghueo Kouipou, Patrick Valere ...
International Nuclear Information System (INIS)
Trubert, D.; Hussonnois, M.; Le Naour, C.; Brillard, L.; Monroy Guzman, F.; Le Du, J.F.; Servajean, V.
1998-01-01
The isotopes 261 Rf and 262 Db were produced by irradiation of a 248 Cm target with respectively 18 O and 19 F ions, at the MP Tandem accelerator of Orsay (France). These isotopes were isolated in HF medium, using he RACHEL setup. Moreover, the radioisotope 262 DB was produced by a nuclear reaction. (authors)
African Journals Online (AJOL)
Assa, Rebecca Rachel. Vol 10, No 3 (2016) - Articles Variation des paramètres biochimiques de l'eau de coco (Cocos nucifera L.) issu de la culture in vitro pendant la période de stockage. Abstract PDF. ISSN: 1997-342X. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...
South African Medical Journal - Vol 90, No 3 (2000)
African Journals Online (AJOL)
Randomised controlled trial of the efficacy of misoprostol used as a cervical ripening agent prior to termination of pregnancy in the first trimester · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Eric T M de Jonge, Rachel Jewkes, Jonathan Levin, Helen Rees, 256-261 ...
African Health Sciences - Vol 6, No 1 (2006)
African Journals Online (AJOL)
... in HIV-1 infected untreated children in Kenya; implication for immunodeficiency and AIDS progression · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Washingtone Ochieng, Dorington Ogoyi, Francis J Mulaa, Simon Ogola, Rachel Musoke, Moses G Otsyula, 3-13 ...
correction of tarsal ectropion following harmful eye medication in a
African Journals Online (AJOL)
Dr O Babalola
Correction of Severe Traditional Medication-induced Lower Lid. Ectropion: A case report. BO Emmanuel. Rachel Eye Center, Abuja. SUMMARY. Introduction: The medical and surgical management of lower lid ectropion induced by the instillation of traditional eye medication in a middle-aged Nigerian woman is described .
Biokemistri - Vol 15, No 1 (2003)
African Journals Online (AJOL)
Effect of aqueous extract of Canavalia ensiformis seeds on hyperlipidaemia and hyperketonaemia in alloxan-induced diabetic rats · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Rachel NIMENIBO-UADIA, 7-15 ...
Lecture notes on behavioural sciences and psychiatry for medical ...
African Journals Online (AJOL)
Adele
started and going. 8. It is useful to request an independent person to provide guidance on this exercise. I would suggest Professor Rachel. Jenkins, Director, WHO Collaboration Centre at the Insti- tute of Psychiatry, University of London. She has demon- strated very keen interest in mental health in developing countries.
Abdominoplasty for Ladd's procedure: optimizing access and esthetics
African Journals Online (AJOL)
Abdominoplasty for Ladd's procedure: optimizing access and esthetics. Rachel Aliotta, Neilendu Kundu, Anthony Stallion, Christi Cavaliere. Abstract. Rotational anomalies occur when there is an abnormal arrest of rotation in the embryonic gut during development. The characteristic population affected is considered to be ...
South Sudan Medical Journal - Vol 6, No 1 (2013)
African Journals Online (AJOL)
Hypertension in Juba, South Sudan: A retrospective cohort study of single blood pressure readings among potential blood donors at Juba Teaching Hospital 2010-2012 · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Rachel Wake, Charles Mazinda, 4-6 ...
Establishment of a Nothofagus alessandrii plantation using different ...
African Journals Online (AJOL)
There is a lack of information regarding the establishment of Nothofagus alessandrii plantations, including any impacts that shading and weed control may have on early survival and growth. A trial was therefore initiated where four shade levels (0% and Rachel® plastic net of 50%, 65%, and 80%) and two weed control ...
Radiation induced changes in the airway - anaesthetic implications ...
African Journals Online (AJOL)
Radiation induced changes in the airway - anaesthetic implications: case report. Mallika Balakrishnan, Renju Kuriakose, Rachel Cherian Koshy. Abstract. Radiation induces a variety of changes in the airway that can potentially lead to difficult intubation. Osteoradionecrosis (ORN) of the mandible, a severe consequence of ...
African Journals Online (AJOL)
NIMENIBO-UADIA, Rachel. Vol 15, No 1 (2003) - Articles Effect of aqueous extract of Canavalia ensiformis seeds on hyperlipidaemia and hyperketonaemia in alloxan-induced diabetic rats. Abstract PDF. ISSN: 0795-8080. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors ...
Correction of Severe Traditional Medication-induced Lower Lid ...
African Journals Online (AJOL)
Setting: The correction of the lower lid tarsal ectropion was carried out at the Rachel Eye Center in Abuja, Nigeria. Result: After conservative intervention failed, a free preauricular skin graft of the floppy ectropion, led to a stable correction. Conclusions: Harmful traditional eye medication continues to be a problem in the ...
South African Medical Journal - Vol 91, No 1 (2001)
African Journals Online (AJOL)
Risk factors for teenage pregnancy among sexually active black adolescents in Cape Town · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Caesar Vundule, Fidelia Maforah, Rachel Jewkes, Esmé Jordaan, 73-80 ...
African Journal of Reproductive Health - Vol 6, No 2 (2002)
African Journals Online (AJOL)
Jennifer Smit, Lynn McFadyen, Abigail Harrison, Khangelani Zuma. Indigenous Healing Practices and Self-Medication amongst Pregnant Women in Cape Town, South Africa. Naeemah Abrahams, Rachel Jewkes, Zodumo Mvo. Tetanus Immunity among Pregnant Women Attending Antenatal Care in Dar es Salaam, ...
Vreugde en verdriet in die huis van Jakob
African Journals Online (AJOL)
p1243322
the children of their slave girls. This article focuses on the quest for happiness, which is evident in the births and name-giving in the house of Jacob. Although true happiness remains elusive, at the end both women receive their dues. God keeps a balance between the two contenders, but the birth of Rachel's son calls for a.
African Journal of Drug and Alcohol Studies - Vol 14, No 2 (2015)
African Journals Online (AJOL)
Substance use literacy: Implications for HIV medication adherence and addiction severity among substance users · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Rachel Maina, Anne A. Obondo, Mary Wangari Kuria, Dennis M. Donovan, 137-151 ...
African Journals Online (AJOL)
Saya, Rachel-Aubain. Vol 200 (2004) - Articles Early selection of Eucalyptus clones in retrospective nursery test using growth, morphological and dry matter criteria, in Republic of Congo : scientific paper. Abstract. ISSN: 2070-2639. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians ...
Coaxing and Persuading: Making Rigorous History Teaching a Departmental Reality
Arscott, Rachel; Hinks, Tom
2016-01-01
Faced with the introduction of a two-year key stage and a new whole-school assessment policy, Rachel Arscott and Tom Hinks decided to make a virtue out of necessity and reconsider their whole approach to planning, teaching and assessment at Key Stage 3. In this article they give an account of the process of reflection and revision they undertook…
Opportunities to Align California's PreK-3 Education System
Policy Analysis for California Education, PACE, 2016
2016-01-01
"PreK-3 Alignment in California's Education System: Obstacles and Opportunities" by Rachel Valentino and Deborah J. Stipek reviews the opportunities and challenges that must be addressed to better align PreK-3 education in California. The report describes policies and practices that districts have implemented to strengthen alignment, and…
Anatomy of a Cancer Treatment Scam
Full Text Available Skip navigation Main Menu Search Utility menu Contact Stay Connected Privacy Policy FTC en español Search form Search Main Menu About the FTC What We Do ... Zapping Rachel Enforcement Cases and Proceedings Case Document Search Refunds Commission Decision Volumes Letters and Statements Petitions ...
2010-06-14
... the plant. The Department reviewed blueprints of the Menasha facility, visited and toured the plant... costly settlement through the consent decree process.'' 119 Cong. Rec. 24,598 (1973) (statement of..., (202) 616-3302, [email protected] . Certificate of Service I, Rachel J. Adcox, hereby certify that...
DEFF Research Database (Denmark)
Elias, Camelia
2012-01-01
, and Tarotist Grand Master Rachel Pollack that: “ghosts are not actually remnants/spirits of dead people, they just believe they are” and investigate to what extent the caliber of the soul, as expressed in tarot cards, can be measured against the background of what can be termed Cartesian 'ghosthesis.'...
That Settles It: The Debate and Consequences of the Homestead Act of 1862
Anderson, Hannah L.
2011-01-01
In 1894, eighteen-year-old Rachel Calof journeyed to North Dakota to homestead with her husband. She wrote that her husband "was convinced that our best chance to make something of ourselves was to avail ourselves of the offer of free land" and that homesteading "seemed a godsend to penniless people who otherwise could not hope to…
2012-03-05
... and Poverty Point State Historic Site and National Monument. These draft nominations are currently in... Historic District) Mount Vernon, Virginia Poverty Point National Monument and State Historic Site... Monument, New Mexico Authority: 16 U.S.C. 470 a-1, a-2, d; 36 CFR 73. Dated: February 10, 2012. Rachel...
Jones, Rebecca
2003-01-01
Brief reviews of six notable education books selected by the editors of "American School Board Journal." Includes books such as Rachel Simmons's "Odd Girl Out: The Hidden Culture of Aggression in Girls," Jonathan Schorr's "Hard Lessons: The Promise of an Inner City Charter School," Peter Irons's "Jim Crow's Children: The Broken Promise of the…
Mitmekesises universumis on praegu matriarhaat / Siram
Siram, pseud., 1968-
2009-01-01
Rahvusvahelise tegevuskunstifestivali "Diverse Universe" performance'i-programmist Pärnus. Eseohe Arhebameni (Nigeeria), rühmituse Rubensid, Rachel Hoffmani (USA) ja Sindy Butzi (Saksamaa), kollektiivi protoPLAY (Inglismaa/Jaapan), Orion Maxted, Beth Greenhalgh, Yoko Ishiguro) performance'itest
Robust Decision Making for Improved Mission Assurance
2014-06-01
Abduction-Based Inquiry” Sub-Project Contributors: - RH: Adam Bryant, Scott Douglass, Jo-Ann Hamilton, Jeff Luehrs, Veda Setlur, Rachel Taylor - RI... Veda Setlur developed a RML model/agent specification environment called “ModelerStudio.” The specification environment is web-delivered for easy
Leadership and Languages: Inspiring Young Linguists
Hawkes, Rachel; Schechter, Sarah
2016-01-01
The Language Leader Award, created by Rachel Hawkes and run by Routes into Languages East "helps pupils learn to lead, using language teaching as the medium. Throughout the year-long programme they develop their leadership and [linguistic] skills, growing in confidence and enhancing their future careers" (Hawkes, n.d. c, p. 1). Some…
Centers for Disease Control (CDC) Podcasts
2012-11-05
In this podcast, CDCâs Dr. Rachel Smith discusses endophthalmitis and focuses on funcal endophthalmitis, including diagnosis and treatment. Created: 11/5/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID). Date Released: 11/5/2012.
Improvising with Material in the Higher Education Dance Technique Class: Exploration and Ownership
Rimmer, Rachel
2013-01-01
In this article the author, Rachel Rimmer, explores how improvisation can facilitate skills that are transferable to other areas of dance practice, enabling different areas of study to complement each other. The experimental forum of improvisation as an alternative method of learning technique is considered, contemplating the value of this…
Management of Perforated Mooren's Ulcer with a Rotational Scleral ...
African Journals Online (AJOL)
2016-12-13
Dec 13, 2016 ... C virus had been demonstrated by Gottsch et al.[9] ... left eye (LE) involving 1½ h was managed with a scleral rotational autograft at the Rachel Eye Center, Abuja. The patient was a .... importation of the tissues can be time‑consuming. When .... and autologous serum eye drops in Mooren's ulcer. Nepal J ...
African Journals Online (AJOL)
Babalola OE, Rachel Eye Center, PO Box 4108, Garki, Abuja. M ESUGA (MBBS). PKATO YOHANA (RN, Diploma in ... This can often best be achieved through eye camps. Outreach programmes also help to define the extent of .... prescribed eye drops for glaucoma. Ophthalmic Surg 1995;. 26(3): 233-6. Thomas R and ...
2012-10-10
... Northeastern Railroad Company--Abandonment Exemption--In Branch and St. Joseph Counties, MI Indiana... Branch County, Mich., and milepost 100.69 near Sturgis in St. Joseph County, Mich. (the Line). The Line... .'' Decided: October 2, 2012. By the Board, Rachel D. Campbell, Director, Office of Proceedings. Derrick A...
Girls in Technology Essay Contest Winner Spends a Day in the Life of a Scientist | FNLCR Staging
Sixteen-year-old Celina Paudel solidified her career interest in biomedical engineering after winning a scholarship through the national Girls in Technology (GIT) program. Then, thanks to Rachel Bagni, she got to see what it really means to be a scie
Empaatiaga äärmustest / Kadri Kõusaar
Kõusaar, Kadri
2007-01-01
Tartu vabaõhu filmifestivaliga "Tartuff - armastuse mitu nägu" paralleelselt toimub rahvusvaheline konverents "Religioonitolerants - võimalus, kohustus, vastutus", millega kaasneb dokfilmide programm Athena keskuses. Artiklis arvustatakse dokumentaalfilmi "Jeesuse laager" ("Jesus Camp") : režissöörid Heidi Ewing, Rachel Grady : Ameerika ühendriigid
Learning about the Game: Designing Science Games for a Generation of Gamers
Chmiel, Marjee
2012-01-01
This paper is a response to "Challenges and Opportunities: Using a science-based video game in secondary school settings" by Rachel Muehrer, Jennifer Jenson, Jeremy Friedberg, and Nicole Husain. The article highlights two critical areas that I argue require more research in the studies of video games in education. The first area focuses on the…
A World Turned Molten: Helping Year 9 to Explore the Cultural Legacies of the First World War
Foster, Rachel
2014-01-01
Rachel Foster shows how her own study of cultural history led to a new dimension in her planning. She wanted to show her students not only that historians are interested in many different kinds of topic, but that they ask different kinds of question about those topics. Foster also wanted her students to examine how civic traditions and rituals…
Reflecting on Teaching of the "Appliance of Science"
Linfield, Rachel
2016-01-01
As a primary school teacher, Rachel Linfield has always been insistent that her students were taught and understood the use behind a particular science fact or process. These days, however, she finds very few students who can recall a single useful science fact that they learned in primary school. Linfield wonders if teaching of the National…
2013-01-03
... Railroad, L.L.C.; Acquisition and Operation Exemption; Buckeye Partners, L.P. Buckeye Hammond Railroad, L.L... acquire from Buckeye Partners, L.P., a noncarrier, and to operate approximately 6,797 feet (1.29 miles) of...: December 26, 2012. By the Board, Rachel D. Campbell, Director, Office of Proceedings. Jeffrey Herzig...
2011-06-17
... Railroad, L.L.C.--Temporary Trackage Rights Exemption--Norfolk Southern Railway Company Norfolk Southern... grant nonexclusive overhead temporary trackage rights to Alabama Southern Railroad, L.L.C. (ABS) over a... http://www.stb.dot.gov . Decided: June 13, 2011. By the Board. Rachel D. Campbell, Director, Office of...
2013-01-04
... Railroad, L.P.--Acquisition and Operation Exemption--Gulf Colorado & San Saba Railway Company Heart of Texas Railroad, L.P. (the Company), a noncarrier, has filed a verified notice of exemption under 49 CFR..., 2013. Rachel D. Campbell, Director, Office of Proceedings. Jeffrey Herzig, Clearance Clerk. [FR Doc...
2012-12-03
... Chicago Railroad, LLC--Acquisition and Operation Exemption--Buckeye Partners, L.P. Buckeye East Chicago... acquire from Buckeye Partners, L.P., a noncarrier, and to operate approximately 7,065 feet (1.34 miles) of..., 2012. By the Board, Rachel D. Campbell, Director, Office of Proceedings. Jeffrey Herzig, Clearance Unit...
Compassion in the workplace? Discrimination against an employee with cancer.
2006-12-01
Rachel is a designer based in the UK. In the following account, she describes the experiences of her colleague Jack, designer and studio manager, during his battles with colon cancer and with his employers. The article raises the issues of difficulties faced in the workplace by patients with cancer and other life-threatening illnesses.
2010-12-01
addition to outlining definitions, data sources, choice theory , game theory , and the economic consequences of terrorism, this study identifies how...stratégiques. Les auteurs sont le Maj Alain Rollin, le Maj Meaghan Setter et Mme Rachel Lea Heide, Ph.D., sous la direction du Lcol William Yee...18 7 Choice Theory and its Applications 7.1
Radical 10-point plan to refocus NHS estate.
Ellis, Conor; Baldwin, Ed; Dick, Rachel
2010-11-01
Conor Ellis, head of health, Ed Baldwin, partner, and Rachel Dick, consultant, at international built asset consultancy EC Harris, present a "10-step guide" to help the NHS achieve radical efficiency savings, optimise the use of its estate, maximise the value of under-utilised land, buildings, and other assets, and harness better value from its existing FM operations.
Statistical Forecasting of Bankruptcy of Defense Contractors. Problems and Prospects
1994-01-01
investors is along the lines of the Capital Asset Pricing Model ( CAPM ). In portfolio theory generally, investors demand an expected-return premium for...Ellen Pint, Rachel Schmidt, and especially Dennis Smallwood of RAND also contributed useful insights and comments. xv Acronyms CAPM Capital Asset ...Bond Yields ............................................. 26 Bond Model Performance ................................. 27 Extensions and Limitations
Homer: A Collection of Critical Essays. Twentieth Century Views Series.
Steiner, George, Ed.; Fagles, Robert, Ed.
One of a series of works aimed at presenting contemporary critical opinion on major authors, this collection includes essays by George Steiner, Leo Tolstoy, Ezra Pound, Erich Auerbach, Edwin Muir, Cedric H. Whitman, Albert B. Lord, W. H. Auden, Ernst Bloch, Georg Lukacs, C. Day Lewis, Gabriel Germain, Franz Kafka, Rachel Bespaloff, Robert…
Growing small youth businesses in Kenya | IDRC - International ...
International Development Research Centre (IDRC) Digital Library (Canada)
Rachel Kalbfleisch, a 2016 IDRC Research Award recipient, wanted to know more ... And, contrary to assumptions, she found that youth pushed into business by ... So was returning to present her findings, including to a research methods class ... as the professor said, a lot of the students have their own informal businesses.
Anatomy of a Cancer Treatment Scam
Full Text Available ... Tech@FTC Comment Policy Contests IoT Home Inspector Challenge Robocalls: Humanity Strikes Back DetectaRobo Zapping Rachel Enforcement ... No FEAR Act USA.gov Accessibility Digital Government Strategy Open Government Federal Trade Commission Headquarters: 600 Pennsylvania ...
In the Flow of Media, Religion, and Culture: A Case Study with TVbyGIRLS
Bischoff, Claire; Bullen, Rebecca Richards; Nemer, Molly; Quednau, Rachel
2011-01-01
This article introduces TVbyGIRLS, a nonprofit organization supporting girls in the development of critical thinking, digital literacy and storytelling, leadership, compassionate collaboration, and social justice engagement. Religious educator Claire Bischoff interviews Rebecca Richards Bullen, TVbyGIRLS mentor, and Molly Nemer and Rachel Quednau,…
Hybridische zelfpositionering en performance in Breytenbachs ...
African Journals Online (AJOL)
het reisverhaal: “Travel writing involves border crossings both literal and .... Rachel Susanna Keet, te beschouwen wanneer hij haar graf niet kan vinden .... The Middle World, inhabited by the bums of the Global Village, is the position of .... “Like a mirror I'm the lair of a collection of impressions, sentiments, ...... Spoils of War.
Eros as godsdiens (of die religieuse viering van seks)
African Journals Online (AJOL)
p1243322
and it fills the world! Like sunshine ... Nelson & Longfellow 1994:71-114).2 Die seksuele en die religieuse word dan gesien as ...... Peace is the way: Bringing war and violence to an end. London: ... Copelan, Rachel 1972. ... Foucault, M 1978.
Leadership for the church: The shepherd model
African Journals Online (AJOL)
2014-05-30
May 30, 2014 ... also monarchical leaders (2 Sm 5:2) and God himself (Is 40:11; Ps 23:1). The prophetic ... referred to are Abraham (Gn 12:16); Rachel (Gn 29:9); Jacob ... these functions are contrary to the shepherds of Ezekiel's era, ..... Volf, M., 1998, After our likeness: The church as the image of the trinity, Wm. B.