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Sample records for clifford roberts md

  1. [Professor Frantisek Por MD and Professor Robert Klopstock MD, students at Budapest and Prague Faculties of Medicine].

    Science.gov (United States)

    Mydlík, M; Derzsiová, K

    2010-11-01

    Professor Frantisek Por MD and Professor Robert Klopstock MD were contemporaries, both born in 1899, one in Zvolen, the other in Dombovar, at the time of Austro-Hungarian Monarchy. Prof. Por attended the Faculty of Medicine in Budapest from 1918 to 1920, and Prof. Klopstock studied at the same place between 1917 and 1919. From 1920 until graduation on 6th February 1926, Prof. Por continued his studies at the German Faculty of Medicine, Charles University in Prague. Prof. Klopstock had to interrupt his studies in Budapest due to pulmonary tuberculosis; he received treatment at Tatranske Matliare where he befriended Franz Kafka. Later, upon Kafka's encouragement, he changed institutions and continued his studies at the German Faculty of Medicine, Charles University in Prague, where he graduated the first great go. It is very likely that, during their studies in Budapest and Prague, both professors met repeatedly, even though their life paths later separated. Following his graduation, Prof. Por practiced as an internist in Prague, later in Slovakia, and from 1945 in Kosice. In 1961, he was awarded the title of university professor of internal medicine at the Faculty of Medicine, Pavol Jozef Safarik University in Kosice, where he practiced until his death in 1980. Prof. Klopstock continued his studies in Kiel and Berlin. After his graduation in 1933, he practiced in Berlin as a surgeon and in 1938 left for USA. In 1962, he was awarded the title of university professor of pulmonary surgery in NewYork, where he died in 1972. PMID:21250499

  2. A 1966 Anesthetic Administered by Robert D. Dripps, M.D., Demonstrated His Experimental Style of Clinical Care.

    Science.gov (United States)

    Johnstone, Robert E; Fleisher, Lee A

    2016-06-01

    Robert D. Dripps, M.D. (1911 to 1973), helped found academic anesthesiology. Newly reviewed teaching slides from the University of Pennsylvania (Philadelphia, Pennsylvania) contain six anesthesia records from 1965 to 1967 that involved Dripps. They illustrate the clinical philosophy he taught-to consider administration of each anesthetic a research study. Intense public criticism in 1967 for improper experimentation on patients during anesthesia changed his clinical and research philosophies and teaching. PMID:27028470

  3. In Remembrance of Robert J. Arceci, M.D., Ph.D. | Office of Cancer Genomics

    Science.gov (United States)

    It is with great sadness and a profound sense of loss that OCG recognizes the untimely passing of Dr. Robert J. Arceci. Dr. Arceci was a co-Principal Investigator for the Acute Myeloid Leukemia (AML) project within the TARGET initiative, which aims to discover novel, more effective treatments for childhood cancers. Dr. Arceci was passionate about the use of cancer genomics to both inform therapeutic approaches in the clinic and expand the field of precision medicine.

  4. Clifford Geometrodynamics

    OpenAIRE

    Lisi, A. Garrett

    2002-01-01

    Classical anti-commuting spinor fields and their dynamics are derived from the geometry of the Clifford bundle over spacetime via the BRST formulation. In conjunction with Kaluza-Klein theory, this results in a geometric description of all the fields and dynamics of the standard model coupled to gravity and provides the starting point for a new approach to quantum gravity.

  5. Idempotents of Clifford Algebras

    OpenAIRE

    Ablamowicz, R.; Fauser, B.; Podlaski, K.; Rembielinski, J.

    2003-01-01

    A classification of idempotents in Clifford algebras C(p,q) is presented. It is shown that using isomorphisms between Clifford algebras C(p,q) and appropriate matrix rings, it is possible to classify idempotents in any Clifford algebra into continuous families. These families include primitive idempotents used to generate minimal one sided ideals in Clifford algebras. Some low dimensional examples are discussed.

  6. Clifford Algebras and Graphs

    OpenAIRE

    Khovanova, Tanya

    2008-01-01

    I show how to associate a Clifford algebra to a graph. I describe the structure of these Clifford graph algebras and provide many examples and pictures. I describe which graphs correspond to isomorphic Clifford algebras and also discuss other related sets of graphs. This construction can be used to build models of representations of simply-laced compact Lie groups.

  7. Clifford Algebra with Mathematica

    OpenAIRE

    Aragon-Camarasa, G.; Aragon-Gonzalez, G; Aragon, J. L.; Rodriguez-Andrade, M. A.

    2008-01-01

    The Clifford algebra of a n-dimensional Euclidean vector space provides a general language comprising vectors, complex numbers, quaternions, Grassman algebra, Pauli and Dirac matrices. In this work, a package for Clifford algebra calculations for the computer algebra program Mathematica is introduced through a presentation of the main ideas of Clifford algebras and illustrative examples. This package can be a useful computational tool since allows the manipulation of all these mathematical ob...

  8. Unitary spaces on Clifford algebras

    OpenAIRE

    Marchuk, N. G.; Shirokov, D. S.

    2007-01-01

    For the complex Clifford algebra Cl(p,q) of dimension n=p+q we define a Hermitian scalar product. This scalar product depends on the signature (p,q) of Clifford algebra. So, we arrive at unitary spaces on Clifford algebras. With the aid of Hermitian idempotents we suggest a new construction of, so called, normal matrix representations of Clifford algebra elements. These representations take into account the structure of unitary space on Clifford algebra.

  9. Metric Clifford Algebra

    OpenAIRE

    Fernández, V. V.; Moya, A. M.; Rodrigues Jr., W. A.

    2002-01-01

    In this paper we introduce the concept of metric Clifford algebra $\\mathcal{C\\ell}(V,g)$ for a $n$-dimensional real vector space $V$ endowed with a metric extensor $g$ whose signature is $(p,q)$, with $p+q=n$. The metric Clifford product on $\\mathcal{C\\ell}(V,g)$ appears as a well-defined \\emph{deformation}(induced by $g$) of an euclidean Clifford product on $\\mathcal{C\\ell}(V)$. Associated with the metric extensor $g,$ there is a gauge metric extensor $h$ which codifies all the geometric inf...

  10. On Clifford neurons and Clifford multi-layer perceptrons.

    Science.gov (United States)

    Buchholz, Sven; Sommer, Gerald

    2008-09-01

    We study the framework of Clifford algebra for the design of neural architectures capable of processing different geometric entities. The benefits of this model-based computation over standard real-valued networks are demonstrated. One particular example thereof is the new class of so-called Spinor Clifford neurons. The paper provides a sound theoretical basis to Clifford neural computation. For that purpose the new concepts of isomorphic neurons and isomorphic representations are introduced. A unified training rule for Clifford MLPs is also provided. The topic of activation functions for Clifford MLPs is discussed in detail for all two-dimensional Clifford algebras for the first time. PMID:18514482

  11. Clifford algebra as quantum language

    OpenAIRE

    Baugh, James; Finkelstein, David Ritz; Galiautdinov, Andrei; Saller, Heinrich

    2000-01-01

    We suggest Clifford algebra as a useful simplifying language for present quantum dynamics. Clifford algebras arise from representations of the permutation groups as they arise from representations of the rotation groups. Aggregates using such representations for their permutations obey Clifford statistics. The vectors supporting the Clifford algebras of permutations and rotations are plexors and spinors respectively. Physical spinors may actually be plexors describing quantum ensembles, not s...

  12. 'Twisted duality' for Clifford Algebras

    OpenAIRE

    Robinson, P. L.

    2014-01-01

    Viewing the complex Clifford algebra $C(V)$ of a real inner product space $V$ as a superalgebra, we offer several proofs of the fact that if $W$ is a subspace of the complexification of $V$ then the supercommutant of the Clifford algebra $C(W)$ is precisely the Clifford algebra $C(W^{\\perp})$.

  13. Clifford numbers and spinors

    CERN Document Server

    Lounesto, Pertti

    1993-01-01

    This volume contains a facsimile reproduction of Marcel Riesz's notes of a set of lectures he delivered at the University of Maryland, College Park, between October 1957 and January 1958, which has not been formally published to date This seminal material (arranged in four chapters), which contributed greatly to the start of modern research on Clifford algebras, is supplemented in this book by notes which Riesz dictated to E Folke Bolinder in the following year and which were intended to be a fifth chapter of the Riesz lecture notes In addition, Riesz's work on Clifford algebra is put into an historical perspective in a separate review by P Lounesto As well as providing an introduction to Clifford algebra, this volume will be of value to those interested in the history of mathematics

  14. Clifford Geertz: A career

    Directory of Open Access Journals (Sweden)

    Bošković Aleksandar

    2007-01-01

    Full Text Available The paper presents some concepts of the recently deceased American anthropologist Clifford Geertz, putting them into the specific context of his rich and interesting career, influences that he had, as well as some reactions to his ideas. A particular attention is placed upon the concept of culture, as the key concept in the 20th century American anthropology.

  15. On parallelizing the Clifford algebra product for CLIFFORD

    OpenAIRE

    Ablamowicz, Rafal; Fauser, Bertfried

    2012-01-01

    We present, as a proof of concept, a way to parallelize the Clifford product in CL_{p,q} for a diagonalized quadratic form as a new procedure `cmulWpar' in the \\Clifford package for \\Maple(R). The procedure uses a new `Threads' module available under Maple 15 (and later) and a new \\Clifford procedure `cmulW' which computes the Clifford product of any two Grassmann monomials in \\CL_{p,q} with a help of Walsh functions. We benchmark `cmulWpar' and compare it to two other procedures `cmulNUM' an...

  16. Clifford Algebras and Spinors

    International Nuclear Information System (INIS)

    Expository notes on Clifford algebras and spinors with a detailed discussion of Majorana, Weyl, and Dirac spinors. The paper is meant as a review of background material, needed, in particular, in now fashionable theoretical speculations on neutrino masses. It has a more mathematical flavour than the over twenty-six-year-old Introduction to Majorana masses [M84] and includes historical notes and biographical data on past participants in the story. (author)

  17. Transgression and Clifford algebras

    OpenAIRE

    Rohr, Rudolf Philippe

    2007-01-01

    Let $W$ be a differential (not necessarily commutative) algebra which carries a free action of a polynomial algebra $SP$ with homogeneous generators $p_1, >..., p_r$. We show that for $W$ acyclic, the cohomology of the quotient $H(W/)$ is isomorphic to a Clifford algebra $\\text{Cl}(P,B)$, where the (possibly degenerate) bilinear form $B$ depends on $W$. This observation is an analogue of an old result of Borel in a non-commutative context. As an application, we study the case of $W$ given by ...

  18. Circles and Clifford Algebras

    OpenAIRE

    Timorin, Vladlen

    2002-01-01

    Consider a smooth map from a neighborhood of the origin in a real vector space to a neighborhood of the origin in a Euclidean space. Suppose that this map takes all germs of lines passing through the origin to germs of Euclidean circles, or lines, or a point. We prove that under some simple additional assumptions this map takes all lines passing though the origin to the same circles as a Hopf map coming from a representation of a Clifford algebra does. We also describe a connection between ou...

  19. On FRT-Clifford Algebras

    OpenAIRE

    Heckenberger, I.; Schueler, A.

    2000-01-01

    We study the q-Clifford algebras Cl_q(N,c), called FRT-Clifford algebras, introduced by Faddeev, Reshetikhin and Takhtajan. It is shown that Cl_q(N,c) acts on the q-exterior algebra \\Lambda(O_q^N). Moreover, explicit formulas for the embedding of U_q(so_N) into Cl_q(N,c) and its relation to the vector and spin representations of U_q(so_N) are given and proved. Key Words: q-Clifford algebra, Drinfeld-Jimbo algebra, spin representation

  20. Diffeological Clifford algebras and pseudo-bundles of Clifford modules

    OpenAIRE

    Pervova, Ekaterina

    2015-01-01

    We consider the diffeological version of the Clifford algebra of a (diffeological) finite-dimensional vector space; we start by commenting on the notion of a diffeological algebra (which is the expected analogue of the usual one) and that of a diffeological module (also an expected counterpart of the usual notion). After considering the natural diffeology of the Clifford algebra, and its expected properties, we turn to our main interest, which is constructing pseudo-bundles of diffeological C...

  1. Clifford Algebras and magnetic monopoles

    International Nuclear Information System (INIS)

    It is known that the introduction of magnetic monopolies in electromagnetism does still present formal problems from the point of view of classical field theory. The author attempts to overcome at least some of them by making recourse to the Clifford Algebra formalism. In fact, while the events of a two-dimensional Minkowski space-time M(1,1) are sufficiently well represented by ordinary Complex Numbers, when dealing with the events of the four-dimensional Minkowski space M(1,3)identical to M/sub 4/ one has of course to look for hypercomplex numbers or, more generally, for the elements of a Clifford Algebra. The author uses the Clifford Algebras in terms of ''multivectors'', and in particular by Hestenes' language, which suits space-time quite well. He recalls that the Clifford product chiγ is the sum of the internal product chi . γ and of the wedge product chiΛγ

  2. Clifford (Geometric) Algebra Wavelet Transform

    OpenAIRE

    Hitzer, Eckhard

    2013-01-01

    While the Clifford (geometric) algebra Fourier Transform (CFT) is global, we introduce here the local Clifford (geometric) algebra (GA) wavelet concept. We show how for $n=2,3 (\\mod 4)$ continuous $Cl_n$-valued admissible wavelets can be constructed using the similitude group $SIM(n)$. We strictly aim for real geometric interpretation, and replace the imaginary unit $i \\in \\C$ therefore with a GA blade squaring to $-1$. Consequences due to non-commutativity arise. We express the admissibility...

  3. A theory of neural computation with Clifford algebras

    OpenAIRE

    Buchholz, Sven

    2005-01-01

    The present thesis introduces Clifford Algebra as a framework for neural computation. Neural computation with Clifford algebras is model-based. This principle is established by constructing Clifford algebras from quadratic spaces. Then the subspace grading inherent to any Clifford algebra is introduced. The above features of Clifford algebras are then taken as motivation for introducing the Basic Clifford Neuron (BCN). As a second type of Clifford neuron the Spinor Clifford Neuron is presente...

  4. Clifford wavelets, singular integrals, and Hardy spaces

    CERN Document Server

    Mitrea, Marius

    1994-01-01

    The book discusses the extensions of basic Fourier Analysis techniques to the Clifford algebra framework. Topics covered: construction of Clifford-valued wavelets, Calderon-Zygmund theory for Clifford valued singular integral operators on Lipschitz hyper-surfaces, Hardy spaces of Clifford monogenic functions on Lipschitz domains. Results are applied to potential theory and elliptic boundary value problems on non-smooth domains. The book is self-contained to a large extent and well-suited for graduate students and researchers in the areas of wavelet theory, Harmonic and Clifford Analysis. It will also interest the specialists concerned with the applications of the Clifford algebra machinery to Mathematical Physics.

  5. Beyond Stabilizer Codes II: Clifford Codes

    OpenAIRE

    Klappenecker, Andreas; Roetteler, Martin

    2000-01-01

    Knill introduced a generalization of stabilizer codes, in this note called Clifford codes. It remained unclear whether or not Clifford codes can be superior to stabilizer codes. We show that Clifford codes are stabilizer codes provided that the abstract error group has an abelian index group. In particular, if the errors are modelled by tensor products of Pauli matrices, then the associated Clifford codes are necessarily stabilizer codes.

  6. Method of averaging in Clifford algebras

    OpenAIRE

    Shirokov, D. S.

    2014-01-01

    In this paper we consider different operators acting on Clifford algebras. We consider Reynolds operator of Salingaros' vee group. This operator average" an action of Salingaros' vee group on Clifford algebra. We consider conjugate action on Clifford algebra. We present a relation between these operators and projection operators onto fixed subspaces of Clifford algebras. Using method of averaging we present solutions of system of commutator equations.

  7. Clifford Geertz. In memoriam

    Directory of Open Access Journals (Sweden)

    Richard Handler

    2008-01-01

    Full Text Available En la primavera de 1991, Adam Kuper, por entonces director de Current Anthropology, y por derecho propio destacado historiador de la disciplina antropológica, me pidió realizar una entrevista a Clifford Geertz. Acepté encantado y ese mismo verano viajé a Princeton, Nueva Jersey, donde transcurrí aproximadamente tres horas con Geertz en su oficina, en el Instituto de Estudios Avanzados. Geertz me dio una cordial bienvenida y habló conmigo sin tapujos, dándome (como podrá comprobar el lector un claro y completo relato de su carrera (para una completa y exacta versión, los lectores pueden consultar ahora su autobiografía en After the Fact: Two Countries, Four Decades, one Anthropolgist, Harvard University Press, 1995. De la transcripción de la entrevista realicé un manuscrito, donde limpié las repeticiones y dubitaciones de la conversación, pero manteniendo fielmente la charla, tal y como tuvo lugar. Se lo mandé a Geertz, que propuso algunas correcciones pero que por lo demás aceptó todo.

  8. Mathematics of CLIFFORD - A Maple package for Clifford and Grassmann algebras

    OpenAIRE

    Ablamowicz, Rafal; Fauser, Bertfried

    2002-01-01

    CLIFFORD performs various computations in Grassmann and Clifford algebras. It can compute with quaternions, octonions, and matrices with entries in Cl(B) - the Clifford algebra of a vector space V endowed with an arbitrary bilinear form B. Two user-selectable algorithms for Clifford product are implemented: 'cmulNUM' - based on Chevalley's recursive formula, and 'cmulRS' - based on non-recursive Rota-Stein sausage. Grassmann and Clifford bases can be used. Properties of reversion in undotted ...

  9. Robert Chambers

    NARCIS (Netherlands)

    K. Biekart (Kees); D.R. Gasper (Des)

    2013-01-01

    textabstractProfessor Robert Chambers is a Research Associate at the Institute of Development Studies (IDS), University of Sussex (Brighton, UK), where he has been based for the last 40 years, including as Professorial Research Fellow. He became involved in the field of development management in the

  10. Symbolic Computations in Higher Dimensional Clifford Algebras

    OpenAIRE

    Ablamowicz, Rafal; Fauser, Bertfried

    2012-01-01

    We present different methods for symbolic computer algebra computations in higher dimensional (\\ge9) Clifford algebras using the \\Clifford\\ and \\Bigebra\\ packages for \\Maple(R). This is achieved using graded tensor decompositions, periodicity theorems and matrix spinor representations over Clifford numbers. We show how to code the graded algebra isomorphisms and the main involutions, and we provide some benchmarks.

  11. Clifford theory for group representations

    CERN Document Server

    Karpilovsky, G

    1989-01-01

    Let N be a normal subgroup of a finite group G and let F be a field. An important method for constructing irreducible FG-modules consists of the application (perhaps repeated) of three basic operations: (i) restriction to FN. (ii) extension from FN. (iii) induction from FN. This is the `Clifford Theory' developed by Clifford in 1937. In the past twenty years, the theory has enjoyed a period of vigorous development. The foundations have been strengthened and reorganized from new points of view, especially from the viewpoint of graded rings and crossed products.The purpos

  12. Linear operators in Clifford algebras

    International Nuclear Information System (INIS)

    We consider the real vector space structure of the algebra of linear endomorphisms of a finite-dimensional real Clifford algebra (2, 4, 5, 6, 7, 8). A basis of that space is constructed in terms of the operators MeI,eJ defined by x→eI.x.eJ, where the eI are the generators of the Clifford algebra and I is a multi-index (3, 7). In particular, it is shown that the family (MeI,eJ) is exactly a basis in the even case. (orig.)

  13. Clifford algebraic symmetries in physics

    International Nuclear Information System (INIS)

    This paper reviews the following appearances of Clifford algebras in theoretical physics: statistical mechanics; general relativity; quantum electrodynamics; internal symmetries; the vee product; classical electrodynamics; charged-particle motion; and the Lorentz group. It is concluded that the power of the Clifford-algebraic description resides in its ability to perform representation-free calculations which are generalizations of the traditional vector algebra and that this considerable computational asset, in combination with the intrinsic symmetry, provides a practical framework for much of theoretical physics. 5 references

  14. Rigidity theorems of Clifford Torus

    Directory of Open Access Journals (Sweden)

    SOUSA JR. LUIZ A. M.

    2001-01-01

    Full Text Available Let M be an n-dimensional closed minimally immersed hypersurface in the unit sphere Sn + 1. Assume in addition that M has constant scalar curvature or constant Gauss-Kronecker curvature. In this note we announce that if M has (n - 1 principal curvatures with the same sign everywhere, then M is isometric to a Clifford Torus .

  15. Robert Recorde

    CERN Document Server

    Williams, Jack

    2011-01-01

    The 16th-Century intellectual Robert Recorde is chiefly remembered for introducing the equals sign into algebra, yet the greater significance and broader scope of his work is often overlooked. This book presents an authoritative and in-depth analysis of the man, his achievements and his historical importance. This scholarly yet accessible work examines the latest evidence on all aspects of Recorde's life, throwing new light on a character deserving of greater recognition. Topics and features: presents a concise chronology of Recorde's life; examines his published works; describes Recorde's pro

  16. On Computational Complexity of Clifford Algebra

    OpenAIRE

    Budinich, Marco

    2009-01-01

    After a brief discussion of the computational complexity of Clifford algebras, we present a new basis for even Clifford algebra Cl(2m) that simplifies greatly the actual calculations and, without resorting to the conventional matrix isomorphism formulation, obtains the same complexity. In the last part we apply these results to the Clifford algebra formulation of the NP-complete problem of the maximum clique of a graph introduced in a previous paper.

  17. Complex structure of a real Clifford algebra

    OpenAIRE

    Hanson, Jason

    2011-01-01

    The classification of real Clifford algebras in terms of matrix algebras is well--known. Here we consider the real Clifford algebra ${\\mathcal Cl}(r,s)$ not as a matrix algebra, but as a Clifford module over itself. We show that ${\\mathcal Cl}(r,s)$ possesses a basis independent complex structure only when the square of the volume element $\\omega$ is -1, in which case it is uniquely given up to sign by right multiplication with $\\omega$.

  18. Clifford Fibrations and Possible Kinematics

    Directory of Open Access Journals (Sweden)

    Alan S. McRae

    2009-07-01

    Full Text Available Following Herranz and Santander [Herranz F.J., Santander M., Mem. Real Acad. Cienc. Exact. Fis. Natur. Madrid 32 (1998, 59-84, physics/9702030] we will construct homogeneous spaces based on possible kinematical algebras and groups [Bacry H., Levy-Leblond J.-M., J. Math. Phys. 9 (1967, 1605-1614] and their contractions for 2-dimensional spacetimes. Our construction is different in that it is based on a generalized Clifford fibration: Following Penrose [Penrose R., Alfred A. Knopf, Inc., New York, 2005] we will call our fibration a Clifford fibration and not a Hopf fibration, as our fibration is a geometrical construction. The simple algebraic properties of the fibration describe the geometrical properties of the kinematical algebras and groups as well as the spacetimes that are derived from them. We develop an algebraic framework that handles all possible kinematic algebras save one, the static algebra.

  19. Introduction to Clifford's Geometric Algebra

    OpenAIRE

    Hitzer, Eckhard

    2013-01-01

    Geometric algebra was initiated by W.K. Clifford over 130 years ago. It unifies all branches of physics, and has found rich applications in robotics, signal processing, ray tracing, virtual reality, computer vision, vector field processing, tracking, geographic information systems and neural computing. This tutorial explains the basics of geometric algebra, with concrete examples of the plane, of 3D space, of spacetime, and the popular conformal model. Geometric algebras are ideal to represen...

  20. Robert Schumann.

    Science.gov (United States)

    Lederman, R J

    1999-01-01

    Robert Schumann, one of the giants of early romantic music, was born in Saxony in 1810 and died in an asylum shortly after his 46th birthday. Early in life, he demonstrated extraordinary skills in both music and journalism; he remained active in both areas until his final illness. His marriage to the remarkable pianist, Clara Wieck, provided him with both much-needed emotional support and a highly effective champion of his music throughout her lengthy career. Schumann's plans to be a concert pianist were thwarted at least partially by an injury to his right hand, the nature of which has been the subject of much speculation. After considering what few facts are available, the author concludes that this may have represented focal dystonia. His compositional output waxed and waned dramatically over his professional life, reflecting to some degree his emotional state. It is considered most likely that he suffered from a major affective disorder, bipolar type. This ultimately led to a suicide attempt in February 1854, and to his eventual death in July 1856. Despite wide-spread and reasonable suspicion that he may have died from neurosyphilis, severe malnutrition from self-starvation seems more likely. PMID:10718523

  1. Braided Clifford algebras as braided quantum groups

    CERN Document Server

    Durdevic, M

    1995-01-01

    The paper deals with braided Clifford algebras, understood as Chevalley-Kahler deformations of braided exterior algebras. It is shown that Clifford algebras based on involutive braids can be naturally endowed with a braided quantum group structure. Basic group entities are constructed explicitly.

  2. Representations of Clifford Algebras and its Applications

    OpenAIRE

    Okubo, Susumu

    1994-01-01

    A real representation theory of real Clifford algebra has been studied in further detail, especially in connection with Fierz identities. As its application, we have constructed real octonion algebras as well as related octonionic triple system in terms of 8-component spinors associated with the Clifford algebras $C(0,7)$ and $C(4,3)$.

  3. An introduction to Clifford algebras and spinors

    CERN Document Server

    Vaz, Jayme

    2016-01-01

    This text explores how Clifford algebras and spinors have been sparking a collaboration and bridging a gap between Physics and Mathematics. This collaboration has been the consequence of a growing awareness of the importance of algebraic and geometric properties in many physical phenomena, and of the discovery of common ground through various touch points: relating Clifford algebras and the arising geometry to so-called spinors, and to their three definitions (both from the mathematical and physical viewpoint). The main point of contact are the representations of Clifford algebras and the periodicity theorems. Clifford algebras also constitute a highly intuitive formalism, having an intimate relationship to quantum field theory. The text strives to seamlessly combine these various viewpoints and is devoted to a wider audience of both physicists and mathematicians. Among the existing approaches to Clifford algebras and spinors this book is unique in that it provides a didactical presentation of the topic and ...

  4. Algebraic spinors on Clifford manifolds

    International Nuclear Information System (INIS)

    A Clifford manifold of n dimensions is defined by the fundamental relation {eμ(x), eν(x)}=2gμν(x)1 between the n frame field components {eμ(x)} and the metric matrix {gμν(x)}. At any point x, the tangent space, orthonormal frames and the spin group are defined in terms of the frame field. Different types of field are classified in terms of their properties under the general linear coordinate transformation group on the manifold, and under spin group transformations. Connections for different types of field are determined by their covariance properties under these two groups. The bivector spin connection is then uniquely determined by the 'uniformity assumption' for Clifford algebraic grades. A key result is established, that the frame field is necessarily covariantly constant on a Clifford manifold, with both vector and spin connections. 'Spin elements' are formed by contracting the frame field with Riemannian vector fields, and possess a 'two-sided' commutator covariant derivative. A set of Riemannian fields orthonormal with respect to the manifold defines an orthonormal set of spin elements in the tangent space, from which idempotents can be constructed. If S is an asymptotically flat (n-1)-dimensional submanifold on which a constant idempotent is defined in terms of a constant spin frame, parallel transport along geodesics from each point of S defines a unique position-dependent extension of the idempotent in a patch P of the manifold. In an earlier model which describes the electroweak interactions of leptons, with a simplification of the Glashow Lagrangian, the 'right-hand' part of the two-sided spin connection gives rise to new gravitational terms. The nature of these new terms is discussed. (author)

  5. Clifford Hopf gebra for two-dimensional space

    OpenAIRE

    Fauser, Bertfried; Oziewicz, Zbigniew

    2000-01-01

    A Clifford algebra Cl(V,\\eta\\in V^*\\otimes V^*) jointly with a Clifford cogebra Cl(V,\\xi\\in V\\otimes V) is said to be a Clifford biconvolution Cl(\\eta,\\xi). We show that a Clifford biconvolution for dim_R Cl=4 does possess an antipode iff det(id-\\xi\\circ\\eta)\

  6. On computational complexity of Clifford algebra

    Science.gov (United States)

    Budinich, Marco

    2009-05-01

    After a brief discussion of the computational complexity of Clifford algebras, we present a new basis for even Clifford algebra Cl(2m) that simplifies greatly the actual calculations and, without resorting to the conventional matrix isomorphism formulation, obtains the same complexity. In the last part we apply these results to the Clifford algebra formulation of the NP-complete problem of the maximum clique of a graph introduced by Budinich and Budinich ["A spinorial formulation of the maximum clique problem of a graph," J. Math. Phys. 47, 043502 (2006)].

  7. The Closed Subsemigroups of a Clifford Semigroup

    Institute of Scientific and Technical Information of China (English)

    Fu Yin-yin; Zhao Xian-zhong

    2014-01-01

    In this paper we study the closed subsemigroups of a Clifford semigroup. It is shown that{∪}Gα | Y′ ∈ P (Y ) is the set of all closed subsemigroups ofα∈Y′a Clifford semigroup S = [Y;Gα;ϕα,β], where Y′ denotes the subsemilattice of Y generated by Y′. In particular, G is the only closed subsemigroup of itself for a group G and each one of subsemilattices of a semilattice is closed. Also, it is shown that the semiring P (S ) is isomorphic to the semiring P (Y ) for a Clifford semigroup S=[Y;Gα;ϕα,β].

  8. Invariants of the local Clifford group

    International Nuclear Information System (INIS)

    We study the algebra of complex polynomials which remain invariant under the action of the local Clifford group under conjugation. Within this algebra, we consider the linear spaces of homogeneous polynomials degree by degree and construct bases for these vector spaces for each degree, thereby obtaining a generating set of polynomial invariants. Our approach is based on the description of Clifford operators in terms of linear operations over GF(2). Such a study of polynomial invariants of the local Clifford group is mainly of importance in quantum coding theory, in particular in the classification of binary quantum codes. Some applications in entanglement theory and quantum computing are briefly discussed as well

  9. Clifford Geertzi mälestusõhtu

    Index Scriptorium Estoniae

    2006-01-01

    10. novembril toimub TLÜ-s Ameerika kultuurantropoloogi Clifford Geertzi mälestusõhtu, kus esinevad rektor Rein Raud, TLÜ Eesti Humanitaarinstituudi antropoloogia keskuse dotsent Lorenzo Cañás Bottos ja kultuuriteooria lektor Marek Tamm

  10. Obstructions to Clifford System Extensions of Algebras

    Indian Academy of Sciences (India)

    Antonio M Cegarra; Antonio R Garzón

    2001-05-01

    In this paper we do phrase the obstruction for realization of a generalized group character, and then we give a classification of Clifford systems in terms of suitable low-dimensional cohomology groups.

  11. Clifford algebras and physical and engineering sciences

    Science.gov (United States)

    Furui, Sadataka

    2013-10-01

    Clifford algebra in physical and engineering science are studied. Roles of triality symmetry of Cartan's spinor in axial anomaly of particle physics and quaternion and octonion in the memristic circuits are discussed.

  12. A diagrammatic categorification of a Clifford algebra

    OpenAIRE

    Tian, Yin

    2013-01-01

    We give a graphical calculus for a categorification of a Clifford algebra and its Fock space representation via differential graded categories. The categorical action is motivated by the gluing action between the contact categories of infinite strips.

  13. The Clifford algebra of a finite morphism

    OpenAIRE

    Krashen, Daniel; Lieblich, Max

    2015-01-01

    We develop a general theory of Clifford algebras for finite morphisms of schemes and describe applications to the theory of Ulrich bundles and connections to period-index problems for curves of genus 1.

  14. Classical particle with spin and Clifford algebra

    International Nuclear Information System (INIS)

    Equations of motion of classical particle with spin in electromagnetic field are derived in terms of the Clifford algebra of the Minkowsky space. The use of the Clifford algebra simplifies the derivation of these equations as well as their form and process of their solving. The equations also get an evident geometric interpretation. The perturbation theory for these equations is formulated which allows to analyze the motion and the polarization of particles in various electromagnetic fields

  15. Clifford algebra, geometric algebra, and applications

    OpenAIRE

    Lundholm, Douglas; Svensson, Lars

    2009-01-01

    These are lecture notes for a course on the theory of Clifford algebras, with special emphasis on their wide range of applications in mathematics and physics. Clifford algebra is introduced both through a conventional tensor algebra construction (then called geometric algebra) with geometric applications in mind, as well as in an algebraically more general form which is well suited for combinatorics, and for defining and understanding the numerous products and operations of the algebra. The v...

  16. The Hyperbolic Clifford Algebra of Multivecfors

    OpenAIRE

    Rodrigues Jr., W. A.; de Souza, Q. A. G.

    2007-01-01

    In this paper we give a thoughtful exposition of the hyperbolic Clifford algebra of multivecfors which is naturally associated with a hyperbolic space, whose elements are called vecfors. Geometrical interpretation of vecfors and multivecfors are given. Poincare automorphism (Hodge dual operator) is introduced and several useful formulas derived. The role of a particular ideal in the hyperbolic Clifford algebra whose elements are representatives of spinors and resume the algebraic properties o...

  17. Inequalities for spinor norms in Clifford algebras

    International Nuclear Information System (INIS)

    In hypercomplex analysis one considers mappings from the euclidean space Rn to its Clifford algebra Rn, where an inequality |uv| ≤ Kn |u||v| holds for u, v in Rn. In this paper the smallest possible value of the constant Kn is determined. As a byproduct the authors present a more detailed description of the faithful matrix representations of Clifford algebras, which might also be useful for other purposes. (author). 8 refs

  18. Octonionic representations of Clifford Algebras and triality

    International Nuclear Information System (INIS)

    The theory of representations of Clifford algebras is extended to employ the division algebra of the octonions or Cayley numbers. In particular, questions that arise from the nonassociativity and noncommutativity of this division algebra are answered. Octonionic representations for Clifford algebras lead to a notion of octonionic spinors and are used to give octoninic representations of the respective orthogonal groups. Finally, the triality automorphisms are shown to exhibit a manifest Σ3x SO(8) structure in this framework

  19. On Clifford representation of Hopf algebras and Fierz identities

    CERN Document Server

    Rodríguez-Romo, S

    1996-01-01

    We present a short review of the action and coaction of Hopf algebras on Clifford algebras as an introduction to physically meaningful examples. Some q-deformed Clifford algebras are studied from this context and conclusions are derived.

  20. Modulo 2 periodicity of complex Clifford algebras and electromagnetic field

    OpenAIRE

    Varlamov, Vadim V.

    1997-01-01

    Electromagnetic field is considered in the framework of Clifford algebra $\\C_2$ over a field of complex numbers. It is shown here that a modulo 2 periodicity of complex Clifford algebras may be connected with electromagnetic field.

  1. Quaternion types of Clifford algebra elements, basis-free approach

    CERN Document Server

    Shirokov, D S

    2011-01-01

    We consider Clifford algebras over the field of real or complex numbers as a quotient algebra without fixed basis. We present classification of Clifford algebra elements based on the notion of quaternion type. This classification allows us to reveal and prove a number of new properties of Clifford algebras. We rely on the operations of conjugation to introduce the notion of quaternion type. Also we find relations between the concepts of quaternion type and rank of Clifford algebra element.

  2. Concepts of trace, determinant and inverse of Clifford algebra elements

    OpenAIRE

    Shirokov, Dmitry

    2011-01-01

    In our paper we consider the notion of determinant of Clifford algebra elements. We present some new formulas for determinant of Clifford algebra elements for the cases of dimension 4 and 5. Also we consider the notion of trace of Clifford algebra elements. We use the generalization of the Pauli's theorem for 2 sets of elements that satisfy the main anticommutation conditions of Clifford algebra.

  3. A method of quaternion typification of Clifford algebra elements

    OpenAIRE

    Shirokov, Dmitry

    2008-01-01

    We present a new classification of Clifford algebra elements. Our classification is based on the notion of quaternion type. Using this classification we develop a method of analysis of commutators and anticommutators of Clifford algebra elements. This method allows us to find out and prove a number of new properties of Clifford algebra elements.

  4. Inverse and Determinant in 0 to 5 Dimensional Clifford Algebra

    OpenAIRE

    Dadbeh, Peruzan

    2011-01-01

    This paper presents equations for the inverse of a Clifford number in Clifford algebras of up to five dimensions. In presenting these, there are also presented formulas for the determinant and adjugate of a general Clifford number of up to five dimensions, matching the determinant and adjugate of the matrix representations of the algebra. These equations are independent of the metric used.

  5. Quregisters, symmetry groups and Clifford algebras

    OpenAIRE

    Cervantes, Dalia; Morales-Luna, Guillermo

    2015-01-01

    The Clifford algebra over the three-dimensional real linear space includes its linear structure and its exterior algebra, the subspaces spanned by multivectors of the same degree determine a gradation of the Clifford algebra. Through these geometric notions, natural one-to-one and two-to-one homomorphisms from $\\mbox{SO}(3)$ into $\\mbox{SU}(2)$ are built conventionally, and the set of qubits, is identified with a subgroup of $\\mbox{SU}(2)$. These constructions are suitable to be extended to c...

  6. Agama dalam Tentukur Antropologi Simbolik Clifford Geertz

    Directory of Open Access Journals (Sweden)

    Yusri Mohamad Ramli

    2012-06-01

    Full Text Available Clifford Geertz can be regarded as one of the most influential figures in religious studies, particularly in the field of anthropology. His unique symbolic anthropology approach had attracted researchers because of his emphasis on deductive reasoning in explaining the meaning of religion and in viewing cultural values that exist in religion. Research based on the content analysis of his works found that Clifford Geertz thought very strongly influenced by Ibn Khaldun as both of them emphasize on the practical reality of religious phenomena in the society. These symbols are then making a cultural system of what we call religion.

  7. Algebra de clifford del espacio tiempo

    OpenAIRE

    Spinel G., Ma. Carolina

    2012-01-01

    En un artículo previo, presentamos la estructura y relaciones básicas del algebra de Clifford Gn generada por el producto geométrico de los vectores de un espacio vectorial Vn sobre el cuerpo de los reales en la versión moderna de Hestenes. Este artículo se dedica a los aspectos fundamentales algebra de Clifford del espacio-tiempo plano (A.E.T.) muestra algunos hechos interesantes relacionados con teoría de Dirac, que ponen de manifiesto la importancia sencillez de la aplicación de algebras d...

  8. Adinkras for Clifford Algebras, and Worldline Supermultiplets

    CERN Document Server

    Doran, C F; Gates, S J; Hübsch, T; Iga, K M; Landweber, G D; Miller, R L

    2008-01-01

    Adinkras are a graphical depiction of representations of the N-extended supersymmetry algebra in one dimension, on the worldline. These diagrams represent the component fields in a supermultiplet as vertices, and the action of the supersymmetry generators as edges. In a previous work, we showed that the chromotopology (topology with colors) of an Adinkra must come from a doubly even binary linear code. Herein, we relate Adinkras to Clifford algebras, and use this to construct, for every such code, a supermultiplet corresponding to that code. In this way, we correlate the well-known classification of representations of Clifford algebras to the classification of Adinkra chromotopologies.

  9. Stabilizer quantum codes over the Clifford algebra

    International Nuclear Information System (INIS)

    The key problem for constructing a stabilizer quantum code is how to create a set of generators for the stabilizer of the stabilizer quantum code, i.e. check matrix. In this paper, we suggest an approach based on the Clifford algebra to create the check matrix for the stabilizer quantum codes. In the proposed approach, the recursive relation of the matrix transform over the Clifford algebra is employed to generate the check matrix. With the proposed approach, a quantum code with any length can be constructed easily. Especially some new codes, which are impossible via previous approaches, are constructed

  10. Quantized Fields à la Clifford and Unification

    Science.gov (United States)

    Pavšič, Matej

    It is shown that the generators of Clifford algebras behave as creation and annihilation operators for fermions and bosons. They can create extended objects, such as strings and branes, and can induce curved metric of our space-time. At a fixed point, we consider the Clifford algebra Cl(8) of the 8D phase space, and show that one quarter of the basis elements of Cl(8) can represent all known particles of the first generation of the Standard model, whereas the other three quarters are invisible to us and can thus correspond to dark matter.

  11. Unifying Clifford algebra formalism for relativistic fields

    International Nuclear Information System (INIS)

    It is shown that a Clifford algebra formalism provides a unifying description of spin-0, -1/2, and -1 fields. Since the operators and operands are both expressed in terms of the same Clifford algebra, the formalism obtains some results which are considerably different from those of the standard of formalisms for these fields. In particular, the conservation laws are obtained uniquely and unambiguously from the equations of motion in this formalism and do not suffer from the ambiguities and inconsistencies of the standard methods

  12. A note on Clifford-Klein forms

    Science.gov (United States)

    Jastrzȩbski, P.; Tralle, A.

    2014-09-01

    We consider the problem of finding Clifford-Klein forms in a class of homogeneous spaces determined by inclusions of real Lie algebras of a special type which we call strongly regular. This class of inclusions is described in terms of their Satake diagrams. For example, the complexifications of such inclusions contain the class of subalgebras generated by automorphisms of finite order. We show that the condition of strong regularity implies the restriction on the real rank of subalgebras. This in part explains why the known examples of Clifford-Klein forms are rare. We make detailed calculations of some known examples from the point of view of the Satake diagrams.

  13. Graded Skew Clifford Algebras that are Twists of Graded Clifford Algebras

    OpenAIRE

    Nafari, Manizheh; Vancliff, Michaela

    2012-01-01

    We prove that if $A$ is a regular graded skew Clifford algebra and is a twist of a regular graded Clifford algebra $B$ by an automorphism, then the subalgebra of $A$ generated by a certain normalizing sequence of homogeneous degree-two elements is a twist of a polynomial ring by an automorphism, and is a skew polynomial ring. We also present an example that demonstrates that this can fail when $A$ is not a twist of $B$.

  14. Thomas Clifford Allbutt and Comparative Pathology

    Science.gov (United States)

    Leung, Danny C. K.

    2008-01-01

    This paper reconceptualizes Thomas Clifford Allbutt's contributions to the making of scientific medicine in late nineteenth-century England. Existing literature on Allbutt usually describes his achievements, such as his design of the pocket thermometer and his advocacy of the use of the ophthalmoscope in general medicine, as independent events;…

  15. Gravitoelectromagnetism in a complex Clifford algebra

    OpenAIRE

    Ulrych, S.

    2006-01-01

    A linear vector model of gravitation is introduced in the context of quantum physics as a generalization of electromagnetism. The gravitoelectromagnetic gauge symmetry corresponds to a hyperbolic unitary extension of the usual complex phase symmetry of electromagnetism. The reversed sign for the gravitational coupling is obtained by means of the pseudoscalar of the underlying complex Clifford algebra.

  16. The Teodorescu Operator in Clifford Analysis

    Institute of Scientific and Technical Information of China (English)

    F.BRACKX; H.De SCHEPPER; M.E.LUNA-ELIZARRAR(A)S; M.SHAPIRO

    2012-01-01

    Euclidean Clifford analysis is a higher dimensional function theory centred around monogenic functions,i.e.,null solutions to a first order vector valued rotation invariant differential operator (θ) called the Dirac operator.More recently,Hermitian Clifford analysis has emerged as a new branch,offering yet a refinement of the Euclidean case; it focuses on the simultaneous null solutions,called Hermitian monogenic functions,to two Hermitian Dirac operators (θ)z_ and (θ)z_(+) which are invariant under the action of the unitary group.In Euclidean Clifford analysis,the Teodorescu operator is the right inverse of the Dirac operator (θ).In this paper,Teodorescu operators for the Hermitian Dirac operators (θ)z_ and (θ)z(+) are constructed.Moreover,the structure of the Euclidean and Hermitian Teodorescu operators is revealed by analyzing the more subtle behaviour of their components.Finally,the obtained inversion relations are still refined for the differential operators issuing from the Euclidean and Hermitian Dirac operators by splitting the Clifford algebra product into its dot and wedge parts.Their relationship with several complex variables theory is discussed.

  17. Clifford Fourier transform on vector fields.

    Science.gov (United States)

    Ebling, Julia; Scheuermann, Gerik

    2005-01-01

    Image processing and computer vision have robust methods for feature extraction and the computation of derivatives of scalar fields. Furthermore, interpolation and the effects of applying a filter can be analyzed in detail and can be advantages when applying these methods to vector fields to obtain a solid theoretical basis for feature extraction. We recently introduced the Clifford convolution, which is an extension of the classical convolution on scalar fields and provides a unified notation for the convolution of scalar and vector fields. It has attractive geometric properties that allow pattern matching on vector fields. In image processing, the convolution and the Fourier transform operators are closely related by the convolution theorem and, in this paper, we extend the Fourier transform to include general elements of Clifford Algebra, called multivectors, including scalars and vectors. The resulting convolution and derivative theorems are extensions of those for convolution and the Fourier transform on scalar fields. The Clifford Fourier transform allows a frequency analysis of vector fields and the behavior of vector-valued filters. In frequency space, vectors are transformed into general multivectors of the Clifford Algebra. Many basic vector-valued patterns, such as source, sink, saddle points, and potential vortices, can be described by a few multivectors in frequency space. PMID:16138556

  18. Clifford algebra in finite quantum field theories

    International Nuclear Information System (INIS)

    We consider the most general power counting renormalizable and gauge invariant Lagrangean density L invariant with respect to some non-Abelian, compact, and semisimple gauge group G. The particle content of this quantum field theory consists of gauge vector bosons, real scalar bosons, fermions, and ghost fields. We assume that the ultimate grand unified theory needs no cutoff. This yields so-called finiteness conditions, resulting from the demand for finite physical quantities calculated by the bare Lagrangean. In lower loop order, necessary conditions for finiteness are thus vanishing beta functions for dimensionless couplings. The complexity of the finiteness conditions for a general quantum field theory makes the discussion of non-supersymmetric theories rather cumbersome. Recently, the F = 1 class of finite quantum field theories has been proposed embracing all supersymmetric theories. A special type of F = 1 theories proposed turns out to have Yukawa couplings which are equivalent to generators of a Clifford algebra representation. These algebraic structures are remarkable all the more than in the context of a well-known conjecture which states that finiteness is maybe related to global symmetries (such as supersymmetry) of the Lagrangean density. We can prove that supersymmetric theories can never be of this Clifford-type. It turns out that these Clifford algebra representations found recently are a consequence of certain invariances of the finiteness conditions resulting from a vanishing of the renormalization group β-function for the Yukawa couplings. We are able to exclude almost all such Clifford-like theories. (author)

  19. Gravitoelectromagnetism in a complex Clifford algebra

    International Nuclear Information System (INIS)

    A linear vector model of gravitation is introduced in the context of quantum physics as a generalization of electromagnetism. The gravitoelectromagnetic gauge symmetry corresponds to a hyperbolic unitary extension of the usual complex phase symmetry of electromagnetism. The reversed sign for the gravitational coupling is obtained by means of the pseudoscalar of the underlying complex Clifford algebra

  20. Physical Holonomy, Thomas Precession, and Clifford Algebra

    International Nuclear Information System (INIS)

    After a general discussion of the physical significance of holonomy group transformations, a relation between the transports of Fermi-Walker and Levi-Civita in Special Relativity is pointed out. A well-known example -the Thomas-Wigner angle - is rederived in a completely frame-independent manner using Clifford algebra. 14 refs. (Author)

  1. Random symmetric matrices on Clifford algebras

    OpenAIRE

    Bakry, Dominique; Zani, Marguerite

    2013-01-01

    We consider Brownian motions and other processes (Ornstein-Uhlenbeck processes, spherical Brownian motions) on various sets of symmetric matrices constructed from algebra structures, and look at their associated spectral measure processes. This leads to the identification of the multiplicity of the eigenvalues, together with the identification of the spectral measures. For Clifford algebras, we thus recover Bott's periodicity.

  2. A Clifford Algebra Description of Polarization Optics

    Science.gov (United States)

    Yevick, David; Soliman, George

    2014-03-01

    The polarization changes induced by optical components are represented as Clifford algebra transformations. This yields a unified formalism for polarized and partially polarized light and for the frequency dependence of polarization in the presence of polarization mode dispersion and polarization dependent loss. Work supported by NSERC.

  3. Robert Gilmore, a portrait

    Science.gov (United States)

    Solari, Hernán G.

    2013-01-01

    To present the personality of Bob Gilmore is a formidable task, as his scientific contributions include group theory, laser physics, non-linear dynamics, catastrophe theory, thermodynamics, dynamical systems, quantum theory and more. But even if we succeed in describing his contributions, much of Gilmore's being would be lost. Bob as advisor, Bob as father, Bob as teacher, Bob as scientific communicator reveal as much of Bob Gilmore as his scientific papers and his books. Very much as in the Group Theory so close to him, there is a Robert Gilmore in abstract as well as representations of Robert Gilmore. We will make an attempt to find the "principle of the rule", the abstract level of Robert Gilmore as well as Robert Gilmore, himself, as a representation of the duality science-humanism.

  4. Disproof of Bell's Theorem by Clifford Algebra Valued Local Variables

    OpenAIRE

    Christian, Joy

    2007-01-01

    It is shown that Bell's theorem fails for the Clifford algebra valued local realistic variables. This is made evident by exactly reproducing quantum mechanical expectation value for the EPR-Bohm type spin correlations observable by means of a local, deterministic, Clifford algebra valued variable, without necessitating either remote contextuality or backward causation. Since Clifford product of multivector variables is non-commutative in general, the spin correlations derived within our local...

  5. Sparse Representations of Clifford and Tensor algebras in Maxima

    OpenAIRE

    Prodanov, Dimiter; Toth, Viktor T.

    2016-01-01

    Clifford algebras have broad applications in science and engineering. The use of Clifford algebras can be further promoted in these fields by availability of computational tools that automate tedious routine calculations. We offer an extensive demonstration of the applications of Clifford algebras in electromagnetism using the geometric algebra G3 = Cl(3,0) as a computational model in the Maxima computer algebra system. We compare the geometric algebra-based approach with conventional symboli...

  6. Clifford Algebra-Valued Wavelet Transform on Multivector Fields

    OpenAIRE

    Bahri, Mawardi; Adji, Sriwulan; Zhao, Jiman

    2010-01-01

    This paper presents a construction of the n = 2 (mod 4) Clifford algebra Cln,0-valued admissible wavelet transform using the admissible similitude group SIM(n), a subgroup of the affine group of Rn. We express the admissibility condition in terms of the Cln,0 Clifford Fourier transform (CFT). We show that its fundamental properties such as inner product, norm relation, and inversion formula can be established whenever the Clifford admissible wavelet satisfies a particular ad...

  7. The Extended Relativity Theory in Clifford Spaces

    CERN Document Server

    Castro, C

    2004-01-01

    A brief review of some of the most important features of the Extended Relativity theory in Clifford-spaces ($C$-spaces) is presented whose " point" coordinates are noncommuting Clifford-valued quantities and which incorporate the lines, areas, volumes,.... degrees of freedom associated with the collective particle, string, membrane,... dynamics of $p$-loops (closed p-branes) living in target $D$-dimensional spacetime backgrounds. $C$-space Relativity naturally incorporates the ideas of an invariant length (Planck scale), maximal acceleration, noncommuting coordinates, supersymmetry, holography, higher derivative gravity with torsion and variable dimensions/signatures that allows to study the dynamics of all (closed) p-branes, for all values of $ p $, on a unified footing. It resolves the ordering ambiguities in QFT and the problem of time in Cosmology. A discussion of the maximal-acceleration Relativity principle in phase-spaces follows along with the study of the invariance group of symmetry transformations ...

  8. The Extended Relativity Theory in Clifford Spaces

    CERN Document Server

    Castro, C

    2004-01-01

    A brief review of some of the most important features of the Extended Relativity theory in Clifford-spaces ( $C$-spaces) is presented whose " point" coordinates are noncommuting Clifford-valued quantities and which incoporate the lines, areas, volumes, .... degrees of freedom associated with the collective particle, string, membrane, ... dynamics of the $p$-loop histories (closed p-branes) living in target $D$-dimensional spacetime backgrounds. $C$-space Relativity naturally incoporates the ideas of an invariant length (Planck scale), maximal acceleration, noncommuting coordinates, supersymmetry, holography, superluminal propagation, higher derivative gravity with torsion and variable dimensions/signatures that allows to study the dynamics of all (closed ) p-branes, for all values of $ p $, in a unified footing. It resolves the ordering ambiguities in QFT and the problem of time in Cosmology. A discussion of the maximal-acceleration Relativity principle in phase-spaces follows along with the study of the inva...

  9. A Clifford analysis approach to superspace

    International Nuclear Information System (INIS)

    A new framework for studying superspace is given, based on methods from Clifford analysis. This leads to the introduction of both orthogonal and symplectic Clifford algebra generators, allowing for an easy and canonical introduction of a super-Dirac operator, a super-Laplace operator and the like. This framework is then used to define a super-Hodge coderivative, which, together with the exterior derivative, factorizes the Laplace operator. Finally both the cohomology of the exterior derivative and the homology of the Hodge operator on the level of polynomial-valued super-differential forms are studied. This leads to some interesting graphical representations and provides a better insight in the definition of the Berezin-integral

  10. Quantum Clifford algebras from spinor representations

    International Nuclear Information System (INIS)

    A general theory of quantum Clifford algebras is presented, based on a quantum generalization of the Cartan theory of spinors. We concentrate on the case when it is possible to apply the quantum-group formalism of bicovariant bimodules. The general theory is then singularized to the quantum SL(n,C) group case, to generate explicit forms for the whole class of braidings required. The corresponding spinor representations are introduced and investigated. Starting from our Clifford algebras we introduce the quantum-Euclidean underlying spaces compatible with different choices of *-structures from where the analogues of Dirac and Laplace operators are built. Using the formalism developed, quantum Spin(n) groups are defined. copyright 1996 American Institute of Physics

  11. Hecke Algebras, SVD, and Other Computational Examples with {\\sc CLIFFORD}

    OpenAIRE

    Ablamowicz, Rafal

    1999-01-01

    {\\sc CLIFFORD} is a Maple package for computations in Clifford algebras $\\cl (B)$ of an arbitrary symbolic or numeric bilinear form B. In particular, B may have a non-trivial antisymmetric part. It is well known that the symmetric part g of B determines a unique (up to an isomorphism) Clifford structure on $\\cl(B)$ while the antisymmetric part of B changes the multilinear structure of $\\cl(B).$ As an example, we verify Helmstetter's formula which relates Clifford product in $\\cl(g)$ to the Cl...

  12. Twin bent functions and Clifford algebras

    OpenAIRE

    Leopardi, Paul C.

    2015-01-01

    This paper examines a pair of bent functions on $\\mathbb{Z}_2^{2m}$ and their relationship to a necessary condition for the existence of an automorphism of an edge-coloured graph whose colours are defined by the properties of a canonical basis for the real representation of the Clifford algebra $\\mathbb{R}_{m,m}.$ Some other necessary conditions are also briefly examined.

  13. Angles between subspaces computed in Clifford Algebra

    OpenAIRE

    Hitzer, Eckhard

    2013-01-01

    We first review the definition of the angle between subspaces and how it is computed using matrix algebra. Then we introduce the Grassmann and Clifford algebra description of subspaces. The geometric product of two subspaces yields the full relative angular information in an explicit manner. We explain and interpret the result of the geometric product of subspaces gaining thus full practical access to the relative orientation information.

  14. 75 FR 49979 - Tony T. Bui, M.D.; Revocation of Registration

    Science.gov (United States)

    2010-08-16

    ....'' Robert A. Leslie, M.D., 68 FR 15227, 15230 (2003). I ``may rely on any one or a combination of factors... girlfriend admitting to a soft- drink adulteration that never occurred.'' Id. at 32. Moreover, even after...

  15. Trix und Robert Haussmann

    OpenAIRE

    Fischli, Fredi; Olsen, Niels

    2012-01-01

    Die Monografie Robert & Trix Haussmann eröffnet die Publikationsreihe STUDIOLO / Edition Patrick Frey, eine Kollaboration des Verlags mit dem Ausstellungsraum STUDIOLO. Die Kuratoren Fredi Fischli und Niels Olsen betreiben in einem Atelierhaus in Zürich ein vielfältiges Programm gegenwärtiger Kunstproduktion. Die Ausstellung The Log-O-Rhythmic Slide Rule im Frühjahr 2012 widmete sich dem Werk von Trix und Robert Haussmann und ist Ausgangspunkt für die folgende Publikation, die mit Bildern, Es...

  16. CONVOLUTION THEOREMS FOR CLIFFORD FOURIER TRANSFORM AND PROPERTIES

    Directory of Open Access Journals (Sweden)

    Mawardi Bahri

    2014-10-01

    Full Text Available The non-commutativity of the Clifford multiplication gives different aspects from the classical Fourier analysis.We establish main properties of convolution theorems for the Clifford Fourier transform. Some properties of these generalized convolutionsare extensions of the corresponding convolution theorems of the classical Fourier transform.

  17. An investigation of symmetry operations with Clifford algebra

    International Nuclear Information System (INIS)

    After presenting Clifford algebra and quaternions, the symmetry operations with Clifford algebra and quaternions are defined. This symmetry operations are applied to a Platonic solid, which is called as dodecahedron. Also, the vertices of a dodecahedron presented in the Cartesian coordinates are calculated (Authors)

  18. Clifford algebras and the classical dynamical Yang-Baxter equation

    OpenAIRE

    Alekseev, Anton; Meinrenken, E.

    2003-01-01

    We describe a relationship of the classical dynamical Yang-Baxter equation with the following elementary problem for Clifford algebras: Given a vector space $V$ with quadratic form $Q_V$, how is the exponential of an element in $\\wedge^2(V)$ under exterior algebra multiplication related to its exponential under Clifford multiplication?

  19. Explicit isomorphisms of real Clifford algebras

    Directory of Open Access Journals (Sweden)

    N. Değırmencı

    2006-06-01

    Full Text Available It is well known that the Clifford algebra Clp,q associated to a nondegenerate quadratic form on ℝn (n=p+q is isomorphic to a matrix algebra K(m or direct sum K(m⊕K(m of matrix algebras, where K=ℝ,ℂ,ℍ. On the other hand, there are no explicit expressions for these isomorphisms in literature. In this work, we give a method for the explicit construction of these isomorphisms.

  20. N=2-extended supersymmetries and Clifford algebras

    International Nuclear Information System (INIS)

    By searching for the largest numbers of one-parameter Lie algebras for one-dimensional supersymmetric harmonic oscillators, we study the impact of fermionic variables associated with fundamental Clifford algebras such as cl2 and cl4. Amongst the sets of associated generators we point out the largest closed superstructures identified as invariance or spectrum generating superalgebras. The additional supersymmetries which do not close under the generalized Lie product lead to new constants of motion. Direct connections with other recent contributions are also singled out. (orig.)

  1. On Clifford's theorem for singular curves

    CERN Document Server

    Franciosi, Marco

    2011-01-01

    Let C be a 2-connected Gorenstein curve either reduced or contained in a smooth algebraic surface and let S be a subcanonical cluster (i.e. a 0-dim scheme such that the space H^0(C, I_S K_C) contains a generically invertible section). Under some general assumptions on S or C we show that h^0(C, I_S K_C) <= p_a(C) - deg (S)/2 and if equality holds then either S is trivial, or C is honestly hyperelliptic or 3-disconnected. As a corollary we give a generalization of Clifford's theorem for reduced curves.

  2. 78 FR 59060 - Gabriel Sanchez, M.D.; Decision and Order

    Science.gov (United States)

    2013-09-25

    ... any compression of the nerves, or the spinal column, or the nerve root,'' and that it was ``difficult... sufficiently reliable to be accepted and relied upon in this .'' See Cynthia M. Cadet, M.D., 76 FR 19450, 19458... factors are . . . considered in the disjunctive.'' Robert A. Leslie, M.D., 68 FR 15227, 15230 (2003)....

  3. Multifractal vector fields and stochastic Clifford algebra

    International Nuclear Information System (INIS)

    In the mid 1980s, the development of multifractal concepts and techniques was an important breakthrough for complex system analysis and simulation, in particular, in turbulence and hydrology. Multifractals indeed aimed to track and simulate the scaling singularities of the underlying equations instead of relying on numerical, scale truncated simulations or on simplified conceptual models. However, this development has been rather limited to deal with scalar fields, whereas most of the fields of interest are vector-valued or even manifold-valued. We show in this paper that the combination of stable Lévy processes with Clifford algebra is a good candidate to bridge up the present gap between theory and applications. We show that it indeed defines a convenient framework to generate multifractal vector fields, possibly multifractal manifold-valued fields, based on a few fundamental and complementary properties of Lévy processes and Clifford algebra. In particular, the vector structure of these algebra is much more tractable than the manifold structure of symmetry groups while the Lévy stability grants a given statistical universality

  4. Multifractal vector fields and stochastic Clifford algebra

    Science.gov (United States)

    Schertzer, Daniel; Tchiguirinskaia, Ioulia

    2015-12-01

    In the mid 1980s, the development of multifractal concepts and techniques was an important breakthrough for complex system analysis and simulation, in particular, in turbulence and hydrology. Multifractals indeed aimed to track and simulate the scaling singularities of the underlying equations instead of relying on numerical, scale truncated simulations or on simplified conceptual models. However, this development has been rather limited to deal with scalar fields, whereas most of the fields of interest are vector-valued or even manifold-valued. We show in this paper that the combination of stable Lévy processes with Clifford algebra is a good candidate to bridge up the present gap between theory and applications. We show that it indeed defines a convenient framework to generate multifractal vector fields, possibly multifractal manifold-valued fields, based on a few fundamental and complementary properties of Lévy processes and Clifford algebra. In particular, the vector structure of these algebra is much more tractable than the manifold structure of symmetry groups while the Lévy stability grants a given statistical universality.

  5. Multifractal vector fields and stochastic Clifford algebra

    Energy Technology Data Exchange (ETDEWEB)

    Schertzer, Daniel, E-mail: Daniel.Schertzer@enpc.fr; Tchiguirinskaia, Ioulia, E-mail: Ioulia.Tchiguirinskaia@enpc.fr [University Paris-Est, Ecole des Ponts ParisTech, Hydrology Meteorology and Complexity HM& Co, Marne-la-Vallée (France)

    2015-12-15

    In the mid 1980s, the development of multifractal concepts and techniques was an important breakthrough for complex system analysis and simulation, in particular, in turbulence and hydrology. Multifractals indeed aimed to track and simulate the scaling singularities of the underlying equations instead of relying on numerical, scale truncated simulations or on simplified conceptual models. However, this development has been rather limited to deal with scalar fields, whereas most of the fields of interest are vector-valued or even manifold-valued. We show in this paper that the combination of stable Lévy processes with Clifford algebra is a good candidate to bridge up the present gap between theory and applications. We show that it indeed defines a convenient framework to generate multifractal vector fields, possibly multifractal manifold-valued fields, based on a few fundamental and complementary properties of Lévy processes and Clifford algebra. In particular, the vector structure of these algebra is much more tractable than the manifold structure of symmetry groups while the Lévy stability grants a given statistical universality.

  6. Multifractal vector fields and stochastic Clifford algebra.

    Science.gov (United States)

    Schertzer, Daniel; Tchiguirinskaia, Ioulia

    2015-12-01

    In the mid 1980s, the development of multifractal concepts and techniques was an important breakthrough for complex system analysis and simulation, in particular, in turbulence and hydrology. Multifractals indeed aimed to track and simulate the scaling singularities of the underlying equations instead of relying on numerical, scale truncated simulations or on simplified conceptual models. However, this development has been rather limited to deal with scalar fields, whereas most of the fields of interest are vector-valued or even manifold-valued. We show in this paper that the combination of stable Lévy processes with Clifford algebra is a good candidate to bridge up the present gap between theory and applications. We show that it indeed defines a convenient framework to generate multifractal vector fields, possibly multifractal manifold-valued fields, based on a few fundamental and complementary properties of Lévy processes and Clifford algebra. In particular, the vector structure of these algebra is much more tractable than the manifold structure of symmetry groups while the Lévy stability grants a given statistical universality. PMID:26723166

  7. On the relation of Manin's quantum plane and quantum Clifford algebras

    International Nuclear Information System (INIS)

    In a recent work we have shown that quantum Clifford algebras - i.e. Clifford algebras of an arbitrary bilinear form - are closely related to the deformed structures as q-spin groups, Hecke algebras, q-Young operators and deformed tensor products. The question to relate Manin's approach to quantum Clifford algebras is addressed here. Explicit computations using the CLIFFORD Maple package are exhibited. The meaning of non-commutative geometry is reexamined and interpreted in Clifford algebraic terms. (author)

  8. John D. Roberts

    OpenAIRE

    Dervan, Peter B.

    1988-01-01

    I met the great John D. Roberts at Caltech for the first time in 1972. He seemed larger than life: a tall, handsome, rugged man with a shock of curly grey hair, broad warm grin, huge embracing handshake, and twinkle in his eye. This was the man who has inspired a generation of organic chemists by his intellectual leadership, his innovation in developing new techniques to explore mechanistic organic chemistry, his contributions to undergraduate and graduate education and the advancement of s...

  9. Clifford algebra approach to the coincidence problem for planar lattices.

    Science.gov (United States)

    Rodríguez, M A; Aragón, J L; Verde-Star, L

    2005-03-01

    The problem of coincidences of planar lattices is analyzed using Clifford algebra. It is shown that an arbitrary coincidence isometry can be decomposed as a product of coincidence reflections and this allows planar coincidence lattices to be characterized algebraically. The cases of square, rectangular and rhombic lattices are worked out in detail. One of the aims of this work is to show the potential usefulness of Clifford algebra in crystallography. The power of Clifford algebra for expressing geometric ideas is exploited here and the procedure presented can be generalized to higher dimensions. PMID:15724067

  10. Valence-band of cubic semiconductors: Clifford algebra approach II

    Energy Technology Data Exchange (ETDEWEB)

    Dargys, A, E-mail: dargys@pfi.l [Semiconductor Physics Institute, A. Gostauto 11, LT-01108 Vilnius (Lithuania)

    2010-07-15

    Application of Clifford algebra in the analysis of valence-band spin properties in semiconductors is considered. In the first part (Dargys A 2009 Phys. Scr. 80 065701), for this purpose the isomorphism between multivectors and their matrix representations was used to transform the problem to Clifford algebra. Here equivalence rules are established between the spinors of Hilbert space and basis elements of the five-dimensional Clifford algebra Cl{sub 4,1}. Then, the rules are applied to the total angular momentum components and the two-band hole Hamiltonian. The resulting biquaternionic Schroedinger equation for hole spin is solved as an example.

  11. Valence-band of cubic semiconductors: Clifford algebra approach II

    International Nuclear Information System (INIS)

    Application of Clifford algebra in the analysis of valence-band spin properties in semiconductors is considered. In the first part (Dargys A 2009 Phys. Scr. 80 065701), for this purpose the isomorphism between multivectors and their matrix representations was used to transform the problem to Clifford algebra. Here equivalence rules are established between the spinors of Hilbert space and basis elements of the five-dimensional Clifford algebra Cl4,1. Then, the rules are applied to the total angular momentum components and the two-band hole Hamiltonian. The resulting biquaternionic Schroedinger equation for hole spin is solved as an example.

  12. On bundles of rank 3 computing Clifford indices

    CERN Document Server

    Lange, H

    2012-01-01

    Let $C$ be a smooth irreducible projective algebraic curve defined over the complex numbers. The notion of the Clifford index of $C$ was extended a few years ago to semistable bundles of any rank. Recent work has been focussed mainly on the rank-2 Clifford index, although interesting results have also been obtained for the case of rank 3. In this paper we extend this work, obtaining improved lower bounds for the rank-3 Clifford index. This allows the first computations of the rank-3 index in non-trivial cases and examples for which the rank-3 index is greater than the rank-2 index.

  13. Kultuurantropoloog Clifford Geertzi mälestusõhtu

    Index Scriptorium Estoniae

    2006-01-01

    Tallinna Ülikoolis peetakse homme Ameerika kultuurantropoloogi Clifford Geertzi mälestusõhtut, esinevad rektor Rein Raud, Eesti Humanitaarinstituudi dotsent Lorenzo Cañás Bottos ja kultuuriteooria lektor Marek Tamm

  14. The γ5-problem and anomalies - a Clifford algebra approach

    International Nuclear Information System (INIS)

    It is shown that a strong correspondence between noncyclicity and anomalies exists. This allows, by fundamental properties of Clifford algebras, to build a simple and consistent scheme for treating γ5 without using (d-4)-dimensional objects. (orig.)

  15. Symplectic, orthogonal and linear Lie groups in Clifford algebra

    OpenAIRE

    Shirokov, D. S.

    2014-01-01

    In this paper we prove isomorphisms between 5 Lie groups (of arbitrary dimension and fixed signatures) in Clifford algebra and classical matrix Lie groups - symplectic, orthogonal and linear groups. Also we obtain isomorphisms of corresponding Lie algebras.

  16. A Clifford algebra associated to generalized Fibonacci quaternions

    OpenAIRE

    Flaut, Cristina

    2014-01-01

    In this paper we find a Clifford algebra associated to generalized Fibonacci quaternions. In this way, we provide a nice algorithm to obtain a division quaternion algebra starting from a quaternion non-division algebra and vice-versa.

  17. Cayley-Dickson and Clifford Algebras as Twisted Group Algebras

    OpenAIRE

    Bales, John W.

    2011-01-01

    The effect of some properties of twisted groups on the associated algebras, particularly Cayley-Dickson and Clifford algebras. It is conjectured that the Hilbert space of square-summable sequences is a Cayley-Dickson algebra.

  18. Clifford algebra and the projective model of Hyperbolic spaces

    OpenAIRE

    Sokolov, Andrey

    2016-01-01

    I apply the algebraic framework developed in [1] to study geometry of hyperbolic spaces in 1, 2, and 3 dimensions. The background material on projectivised Clifford algebras and their application to Cayley-Klein geometries is described in [2].

  19. Composite bundles in Clifford algebras. Gravitation theory. Part I

    CERN Document Server

    Sardanashvily, G

    2016-01-01

    Based on a fact that complex Clifford algebras of even dimension are isomorphic to the matrix ones, we consider bundles in Clifford algebras whose structure group is a general linear group acting on a Clifford algebra by left multiplications, but not a group of its automorphisms. It is essential that such a Clifford algebra bundle contains spinor subbundles, and that it can be associated to a tangent bundle over a smooth manifold. This is just the case of gravitation theory. However, different these bundles need not be isomorphic. To characterize all of them, we follow the technique of composite bundles. In gravitation theory, this technique enables us to describe different types of spinor fields in the presence of general linear connections and under general covariant transformations.

  20. On generalized Clifford algebras and their physical applications

    OpenAIRE

    Jagannathan, R.

    2010-01-01

    Generalized Clifford algebras (GCAs) and their physical applications were extensively studied for about a decade from 1967 by Alladi Ramakrishnan and his collaborators under the name of L-matrix theory. Some aspects of GCAs and their physical applications are outlined here. The topics dealt with include: GCAs and projective representations of finite abelian groups, Alladi Ramakrishnan's sigma operation approach to the representation theory of Clifford algebra and GCAs, Dirac's positive energy...

  1. Scalable randomized benchmarking of non-Clifford gates

    OpenAIRE

    Cross, Andrew W.; Magesan, Easwar; Bishop, Lev S.; Smolin, John A.; Gambetta, Jay M.

    2015-01-01

    Randomized benchmarking is a widely used experimental technique to characterize the average error of quantum operations. Benchmarking procedures that scale to enable characterization of $n$-qubit circuits rely on efficient procedures for manipulating those circuits and, as such, have been limited to subgroups of the Clifford group. However, universal quantum computers require additional, non-Clifford gates to approximate arbitrary unitary transformations. We define a scalable randomized bench...

  2. On continuity of homomorphisms between topological Clifford semigroups

    OpenAIRE

    I. Pastukhova

    2014-01-01

    Generalizing an old result of Bowman we prove that a homomorphism $f:X\\to Y$ between topological Clifford semigroups is continuous if the idempotent band $E_X=\\{x\\in X:xx=x\\}$ of $X$ is a $V$-semilattice;the topological Clifford semigroup $Y$ is ditopological;the restriction $f|E_X$ is continuous;for each subgroup $H\\subset X$ the restriction $f|H$ is continuous.

  3. Clifford Algebras in Symplectic Geometry and Quantum Mechanics

    OpenAIRE

    Binz, Ernst; de Gosson, Maurice A.; Hiley, Basil J.

    2011-01-01

    The necessary appearance of Clifford algebras in the quantum description of fermions has prompted us to re-examine the fundamental role played by the quaternion Clifford algebra, C(0,2). This algebra is essentially the geometric algebra describing the rotational properties of space. Hidden within this algebra are symplectic structures with Heisenberg algebras at their core. This algebra also enables us to define a Poisson algebra of all homogeneous quadratic polynomials on a two-dimensional s...

  4. Real representations of finite Clifford algebras. I. Classification

    International Nuclear Information System (INIS)

    A classification of real matrix irreducible representations of finite-dimensional real Clifford algebras has been made. In contrast to the case of complex representation, three distinct types of representations can be obtained which we call normal, almost complex, and quaternionic. The dimension of the latter two cases is twice as large as that of the normal representation. A criteria for a given Clifford algebra to possess a particular type of the representations is also given with some applications

  5. Representation of Crystallographic Subperiodic Groups in Clifford's Geometric Algebra

    OpenAIRE

    Hitzer, Eckhard; Ichikawa, Daisuke

    2013-01-01

    This paper explains how, following the representation of 3D crystallographic space groups in Clifford's geometric algebra, it is further possible to similarly represent the 162 so called subperiodic groups of crystallography in Clifford's geometric algebra. A new compact geometric algebra group representation symbol is constructed, which allows to read off the complete set of geometric algebra generators. For clarity moreover the chosen generators are stated explicitly. The group symbols are ...

  6. Clifford algebras and the quantization of the free Dirac field

    International Nuclear Information System (INIS)

    In this paper we study the Clifford algebra of the Minkowski space and prove that any of its irreducible representations carries a canonical representation of a cover group of the Lorentz group, a canonical sesquilinear hermitian form, a canonical conjugation and a canonical antilinear operator called the charge conjugation. We also consider the problem of the quantization of the free Dirac field, in connection with the infinite dimensional Clifford algebra associated to the space of classical fields. (Author)

  7. The Stabilized Poincare-Heisenberg algebra: a Clifford algebra viewpoint

    OpenAIRE

    Gresnigt, N. G.; Renaud, P. F.; Butler, P. H.

    2006-01-01

    The stabilized Poincare-Heisenberg algebra (SPHA) is the Lie algebra of quantum relativistic kinematics generated by fifteen generators. It is obtained from imposing stability conditions after attempting to combine the Lie algebras of quantum mechanics and relativity which by themselves are stable, however not when combined. In this paper we show how the sixteen dimensional Clifford algebra CL(1,3) can be used to generate the SPHA. The Clifford algebra path to the SPHA avoids the traditional ...

  8. Dirac cohomology for the degenerate affine Hecke Clifford algebra

    OpenAIRE

    Chan, Kei Yuen

    2013-01-01

    We define an analogue of the Dirac operator for the degenerate affine Hecke-Clifford algebra. A main result is to relate the central characters of the degenerate affine Hecke-Clifford algebra with the central characters of the Sergeev algebra via Dirac cohomology. The action of the Dirac operator on certain modules is also computed. Results in this paper could be viewed as a projective version of the Dirac cohomology of the degenerate affine Hecke algebra.

  9. Robert Grosseteste's colours

    CERN Document Server

    Sparavigna, Amelia Carolina

    2013-01-01

    Here I am proposing a translation and discussion of the De Colore, one of the short scientific treatises written by Robert Grosseteste. In this very short treatise of the mid-1220s, Grosseteste continued the discussion on light and colours he started in the De Iride. He describes two manners of counting colours: one gives an infinity of tones, the other counts seven colours. In both cases, colours are created by the purity or impurity of the transparent medium when light is passing through it. This medieval framework survived until Newton's experiments with prisms.

  10. Remembering Robert Seydel

    Directory of Open Access Journals (Sweden)

    Lauren van Haaften­-Schick

    2011-06-01

    Full Text Available This January, while preparing a new course, Robert Seydel was struck and killed by an unexpected heart attack. He was a critically under-appreciated artist and one of the most beloved and admired professors at Hampshire College.At the time of his passing, Seydel was on the brink of a major artistic and career milestone. His Book of Ruth was being prepared for publication by Siglio Press. His publisher describes the book as: “an alchemical assemblage that composes the life of his alter ego, Ruth Greisman— spinster, Sunday painter, and friend to Joseph Cornell and Marcel Duchamp. Through collages, drawings, and journal entries from Ruth’s imagined life, Seydel invokes her interior world in novelistic rhythms.”This convergence of his professional triumph with the tragedy of his death makes now a particularly appropriate time to think about Robert Seydel and his work. This feature contains a selection of excerpts from Book of Ruth (courtesy of Siglio Press alongside a pair of texts remembering him and giving critical and biographical insights into his art and his person. These texts, from a former student and a colleague respectively, were originally prepared for Seydel's memorial at Hampshire College and have since been revised for publication in continent.

  11. Robert Cailliau honoured by Belgium

    CERN Multimedia

    2004-01-01

    On 15 November, Robert Cailliau received the distinction of Commandeur de l'Ordre de Léopold from Belgium, his home country, for his pioneering work in developing the World Wide Web. Robert Cailliau worked closely with Tim Berners-Lee, the inventor of the Web.

  12. k-deformed Poincare algebras and quantum Clifford-Hopf algebras

    OpenAIRE

    da Rocha, Roldao; Bernardini, Alex E.; Vaz Jr, Jayme

    2008-01-01

    The Minkowski spacetime quantum Clifford algebra structure associated with the conformal group and the Clifford-Hopf alternative k-deformed quantum Poincare algebra is investigated in the Atiyah-Bott-Shapiro mod 8 theorem context. The resulting algebra is equivalent to the deformed anti-de Sitter algebra U_q(so(3,2)), when the associated Clifford-Hopf algebra is taken into account, together with the associated quantum Clifford algebra and a (not braided) deformation of the periodicity Atiyah-...

  13. Application of the method of quaternion typification for finding subalgebras and Lie subalgebras of Clifford algebras

    OpenAIRE

    Shirokov, Dmitry

    2009-01-01

    In this paper we further develop the method of quaternion typification of Clifford algebra elements suggested by the author in the previous papers. On the basis of new classification of Clifford algebra elements it is possible to find out and prove a number of new properties of Clifford algebra. In particular, we find subalgebras and Lie subalgebras of Clifford algebra and subalgebras of the Lie algebra of the pseudo-unitary Lie group.

  14. Clifford modules and invariants of quadratic forms

    CERN Document Server

    Karoubi, Max

    2010-01-01

    Let A be a commutative ring with 1/2 in A. In this paper, we define new characteristic classes for finitely generated projective A-modules V provided with a non degenerate quadratic form. These classes belong to the usual K-theory of A. They generalize in some sense the classical "cannibalistic" Bott classes in topological K-theory, when A is the ring of continuous functions on a compact space X. To define these classes, we replace the topological Thom isomorphism by a Morita equivalence between A-modules and C(V)-modules, where C(V) denotes the Clifford algebra of V, assuming that the class of C(V) in the graded Brauer group of A is trivial. We then essentially use ideas going back to Atiyah, Bott and Shapiro together with an alternative definition of the Adams operations due to Atiyah. When C(V) is not trivial in the graded Brauer group, the characteristic classes take their values in an algebraic analog of twisted K-theory. Finally, we also make use of a letter written by J.-P. Serre to the author, in orde...

  15. Spin Singularities: Clifford Kaleidoscopes and Particle Masses

    CERN Document Server

    Cohen, Marcus S

    2009-01-01

    Are particles singularities- vortex lines, tubes, or sheets in some global ocean of dark energy? We visit the zoo of Lagrangian singularities, or caustics in a spin(4,C) phase flow over compactifed Minkowsky space, and find that their varieties and energies parallel the families and masses of the elementary particles. Singularities are classified by tensor products of J Coxeter groups s generated by reflections. The multiplicity, s, is the number reflections needed to close a cycle of null zigzags: nonlinear resonances of J chiral pairs of lightlike matter spinors with (4-J) Clifford mirrors: dyads in the remaining unperturbed vacuum pairs. Using singular perturbations to "peel" phase-space singularities by orders in the vacuum intensity, we find that singular varieties with quantized mass, charge, and spin parallel the families of leptons (J=1), mesons (J=2), and hadrons (J=3). Taking the symplectic 4 form - the volume element in the 8- spinor phase space- as a natural Lagrangian, these singularities turn ou...

  16. Quantum Clifford algebra from classical differential geometry

    International Nuclear Information System (INIS)

    We show the emergence of Clifford algebras of nonsymmetric bilinear forms as cotangent algebras of Kaluza-Klein (KK) spaces pertaining to teleparallel space-times. These spaces are canonically determined by the horizontal differential invariants of Finsler bundles of the type, B'(M)→S(M), where B'(M) is the set of all the tangent frames to a differentiable manifold M, and where S(M) is the sphere bundle. If M is space-time itself, M4, the 'geometric phase space', S(M4), has dimension seven. This reformulation of the horizontal invariants as pertaining to a KK space removes the mismatch between the dimensionality of the tangent frames to M4 and the dimensionality of S(M4). In the KK space, a symmetric tangent metric induces a cotangent metric which is not symmetric in general. An interior covariant derivative in the sense of Kaehler is defined. It involves the antisymmetric part of the cotangent metric, which thus enters electrodynamics and the Dirac equation

  17. The naked spinor a rewrite of Clifford algebra

    CERN Document Server

    Morris, Dennis

    2015-01-01

    This book is about spinors. The whole mathematical theory of spinors is within Clifford algebra, and so this book is about Clifford algebra. Spinor theory is really the theory of empty space, and so this book is about empty space. The whole of Clifford algebra is rewritten in a much simpler form, and so the whole of spinor theory is rewritten in a much simpler form. Not only does this book make Clifford algebra simple and obvious, but it lifts the fog and mirrors from this area of mathematics to make it clear and obvious. In doing so, the true nature of spinors is revealed to the reader, and, with that, the true nature of empty space. To understand this book you will need an elementary knowledge of linear algebra (matrices) an elementary knowledge of finite groups and an elementary knowledge of the complex numbers. From no more than that, you will gain a very deep understanding of Clifford algebra, spinors, and empty space. The book is well written with all the mathematical steps laid before the reader in a w...

  18. On Generalized Clifford Algebras and Spin Lattice Systems

    International Nuclear Information System (INIS)

    The incessantly growing area of applications of Clifford algebras and naturalness of their use in formulating problems for direct calculation entitles one to call them Clifford numbers. The generalized ''universal'' Clifford numbers are here introduced via k-ubic form Qk replacing quadratic one in familiar construction of an appropriate ideal of tensor algebra. One of the epimorphic images of universal algebras k - Cn = T(V)/I(Qk) is the algebra Cln(k) with n generators and these are the algebras to be used here. Because generalized Clifford algebras Cln(k) possess inherent Zk x Zk x Λ XZk grading - this makes them an efficient apparatus to deal with spin lattice systems. This efficiency is illustrated here by derivation of two major observations. Namely - partition functions for vector and planar Potts models and other model with Zn invariant Hamiltonian are polynomials in generalized hyperbolic functions of the n-th order. Secondly, the problem of algorithmic calculation of the partition function for any vector Potts model as treated here is reduced to the calculation of Tr(γi1..γis ), where γ's are the generators of the generalized Clifford algebra. Finally the expression for Tr(γi1..γis), for arbitrary collection of such y matrices is derived. (author)

  19. Method of generalized Reynolds operators and Pauli's theorem in Clifford algebras

    OpenAIRE

    Shirokov, D. S.

    2014-01-01

    We consider real and complex Clifford algebras of arbitrary even and odd dimensions and prove generalizations of Pauli's theorem for two sets of Clifford algebra elements that satisfy the main anticommutative conditions. In our proof we use some special operators - generalized Reynolds operators. This method allows us to obtain an algorithm to compute elements that connect two different sets of Clifford algebra elements.

  20. The Clifford-Fourier transform $\\mathcal{F}_O$ and monogenic extensions

    OpenAIRE

    Lopez, Arnoldo Bezanilla; Sanchez, Omar Leon

    2014-01-01

    Several versions of the Fourier transform have been formulated in the framework of Clifford algebra. We present a (Clifford-Fourier) transform, constructed using the geometric properties of Clifford algebra. We show the corresponding results of operational calculus. We obtain a technique to construct monogenic extensions of a certain type of continuous functions, and versions of the Paley-Wiener theorems are formulated.

  1. Hole spin precession in semiconductors: Clifford algebra approach

    International Nuclear Information System (INIS)

    Recently the Clifford (geometrical) algebra was addressed to describe dynamical properties of electron spin in semiconductors (Dargys 2009 Phys. Scr. 79 055702). In this paper, the Clifford algebra is used to investigate heavy and light hole spins in valence bands of cubic semiconductors. Owing to strong spin-orbit interaction in the valence band, the precession trajectories of hole spin polarization are ellipses, or even lines, rather than circles as usually found in the case of electrons. The paper shows how one can investigate the valence band spectrum and free-hole spin precession trajectories within a framework of the Clifford algebra Cl4,1. General formulae that describe free heavy- and light-mass hole spin precession are presented.

  2. Clifford algebraic approach to superfields and some consequences

    International Nuclear Information System (INIS)

    Frames provided by Clifford algebras C/sub n/ are considered for the purpose of expanding a field multiplet (containing, possibly, both bosons and fermions). After giving a brief--mainly geometrical--description of Clifford algebras, the main tools of the present scheme are introduced: a scalar product in C/sub n/, a conjugation operation, and a ''Lorentz covariant derivative.'' It is described how these Clifford algebraic tools can be applied in order to obtain free massless Lagrangian expressions for a number of field theoretical models. It is also shown how gauge fields can arise within this scheme. It appears possible that the suggested formalism can lead naturally to spinor field operators as ''gauge fields.'' A specific example which can lead to a two-component ''gauge spinor'' is discussed. Possible lines of investigation which could solidify this potentially rich approach are suggested. (1 figure, 1 table)

  3. Clifford Algebra Implying Three Fermion Generations Revisited

    International Nuclear Information System (INIS)

    The author's idea of algebraic compositeness of fundamental particles, allowing to understand the existence in Nature of three fermion generations, is revisited. It is based on two postulates. Primo, for all fundamental particles of matter the Dirac square-root procedure √p2 → Γ(N)·p works, leading to a sequence N=1, 2, 3, ... of Dirac-type equations, where four Dirac-type matrices Γ(N)μ are embedded into a Clifford algebra via a Jacobi definition introducing four ''centre-of-mass'' and (N - 1) x four ''relative'' Dirac-type matrices. These define one ''centre-of-mass'' and N - 1 ''relative'' Dirac bispinor indices. Secundo, the ''centre-of-mass'' Dirac bispinor index is coupled to the Standard Model gauge fields, while N - 1 ''relative'' Dirac bispinor indices are all free indistinguishable physical objects obeying Fermi statistics along with the Pauli principle which requires the full antisymmetry with respect to ''relative'' Dirac indices. This allows only for three Dirac-type equations with N = 1, 3, 5 in the case of N odd, and two with N = 2, 4 in the case of N even. The first of these results implies unavoidably the existence of three and only three generations of fundamental fermions, namely leptons and quarks, as labelled by the Standard Model signature. At the end, a comment is added on the possible shape of Dirac 3 x 3 mass matrices for four sorts of spin-1/2 fundamental fermions appearing in three generations. For charged leptons a prediction is mτ = 1776.80 MeV, when the input of experimental me and mμ is used. (author)

  4. Extending Fourier transformations to Hamilton's quaternions and Clifford's geometric algebras

    Science.gov (United States)

    Hitzer, Eckhard

    2013-10-01

    We show how Fourier transformations can be extended to Hamilton's algebra of quaternions. This was initially motivated by applications in nuclear magnetic resonance and electric engineering. Followed by an ever wider range of applications in color image and signal processing. Hamilton's algebra of quaternions is only one example of the larger class of Clifford's geometric algebras, complete algebras encoding a vector space and all its subspace elements. We introduce how Fourier transformations are extended to Clifford algebras and applied in electromagnetism, and in the processing of images, color images, vector field and climate data.

  5. Clifford, Dirac, and Majorana algebras, and their representations

    International Nuclear Information System (INIS)

    We show that the Dirac algebra is an algebra in five dimensions. It has traditionally been confused with the two distinct algebras in four dimensions, which we have identified as the Majorana algebra and the Clifford algebra in Minkowski space-time. A careful discussion of the subtle inter-relationship between these three algebras is achieved by employing a basis of differential forms. In addition, we provide for the first time a 4 x 4 complex matrix representation of the Clifford algebra in Minkowski spacetime, and compare it to the matrix representations of the Dirac and Majorana algebras. A remark on Eddington's E-numbers is included

  6. On the relationship between twistors and Clifford algebras

    International Nuclear Information System (INIS)

    Basis p-forms of a complexified Minkowski spacetime can be used to realize a Clifford algebra isomorphic to the Dirac algebra of γ matrices. Twistor space is then constructed as a spin of this abstract algebra through a Witt decomposition of the Minkowski space. We derive explicit formulas relating the basis p-forms to index one twistors. Using an isomorphism between the Clifford algebra and a space of index two twistors, we expand a suitably defined antisymmetric index two twistor basis on p-forms of ranks zero, one, and four. Together with the inverse formula they provide a complete passage between twistors and p-forms. (orig.)

  7. The investigation of platonic solids symmetry operations with clifford algebra

    International Nuclear Information System (INIS)

    The geometric algebra produces the new fields of view in the modern mathematical physics, definition of bodies and rearranging for equations of mathematics and physics. The new mathematical approaches play an important role in the progress of physics. After presenting Clifford algebra and quarantine's, the symmetry operations with Clifford algebra and quarantine's are defined. This symmetry operations are applied to a Platonic solids, which are called as tetrahedron, cube, octahedron, icosahedron and dodecahedron. Also, the vertices of Platonic solids presented in the Cartesian coordinates are calculated

  8. Weak Values: Approach through the Clifford and Moyal Algebras

    International Nuclear Information System (INIS)

    In this paper we calculate various transition probability amplitudes, TPAs, known as 'weak values' for the Schrödinger and Pauli particles. It is shown that these values are related to the Bohm momentum, the Bohm energy and the quantum potential in each case. The results for the Schrödinger particle are obtained in three ways, the standard approach, the Clifford algebra approach of Hiley and Callaghan, and the Moyal approach. To obtain the results for the Pauli particle, we combine the Clifford and Moyal algebras into one structure. The consequences of these results are discussed.

  9. Certain Clifford-like algebra and quantum vertex algebras

    OpenAIRE

    Li, Haisheng; Tan, Shaobin; Wang, Qing

    2015-01-01

    In this paper, we study in the context of quantum vertex algebras a certain Clifford-like algebra introduced by Jing and Nie. We establish bases of PBW type and classify its $\\mathbb N$-graded irreducible modules by using a notion of Verma module. On the other hand, we introduce a new algebra, a twin of the original algebra. Using this new algebra we construct a quantum vertex algebra and we associate $\\mathbb N$-graded modules for Jing-Nie's Clifford-like algebra with $\\phi$-coordinated modu...

  10. Robert Smithsoni ülevaade

    Index Scriptorium Estoniae

    1999-01-01

    Ameerika maakunstniku Robert Smithsoni (1938-1973) retrospektiivnäitus 12. sept.-ni Stockholmi Moodsa Kunsti Muuseumis. Kunstnikule maailmakuulsuse toonud tööst, 1970. a. Utah' osariigi Suurde Soolajärve ehitatud spiraalmuulist "Spiral Jetty".

  11. Genetics Home Reference: Roberts syndrome

    Science.gov (United States)

    ... mechanism underlying Roberts syndrome involves loss of ESCO2 acetyltransferase activity. Hum Mol Genet. 2008 Jul 15;17( ... Zou H. Two human orthologues of Eco1/Ctf7 acetyltransferases are both required for proper sister-chromatid cohesion. ...

  12. Robert Lepiksoni maailm / Eha Komissarov

    Index Scriptorium Estoniae

    Komissarov, Eha, 1947-

    2000-01-01

    Näitus "Minu maailm. Robert Lepikson fotograafina ja kollektsionäärina" galeriis "Vaal". Väljas on loodusfotod, fotod autodest, kunstikogust Eduard Steinbergi (1937) ja Vladimir Nemuhhini (1925) maalid, paar Salvador Dali värvilist litograafiat

  13. Clifford Hopf-gebra and Bi-universal Hopf-gebra

    CERN Document Server

    Oziewicz, Z

    1997-01-01

    We consider a pair of independent scalar products, one scalar product on vectors, and another independent scalar product on dual space of co-vectors. The Clifford co-product of multivectors is calculated from the dual Clifford algebra. With respect to this co-product unit is not group-like and vectors are not primitive. The Clifford product and the Clifford co-product fits to the bi-gebra with respect to the family of the (pre)-braids. The Clifford bi-gebra is in a braided category iff at least one of these scalar products vanish.

  14. Clifford Hopf-gebra and Bi-universal Hopf-gebra

    OpenAIRE

    Oziewicz, Zbigniew

    1997-01-01

    We consider a pair of independent scalar products, one scalar product on vectors, and another independent scalar product on dual space of co-vectors. The Clifford co-product of multivectors is calculated from the dual Clifford algebra. With respect to this co-product unit is not group-like and vectors are not primitive. The Clifford product and the Clifford co-product fits to the bi-gebra with respect to the family of the (pre)-braids. The Clifford bi-gebra is in a braided category iff at lea...

  15. Robert K. Merton

    Directory of Open Access Journals (Sweden)

    Gonzalo Cataño

    2003-01-01

    Full Text Available El 23 de febrero de 2003 murió en la ciudad de Nueva York el sociólogo norteamericano Robert King Merton. Teniendo presente que no es fácil resumir en unas pocas páginas la obra de quien se dedicó durante 66 años del siglo XX a una intensa actividad teórica y docente en Sociología, el artículo sintetiza algunos de los rasgos mas sobresalientes de su extensa obra.Su carrera académica se desarrolló a partir del legado de las figuras de la tradición sociológica europea y norteamericana que habían afirmado de manera definitiva los conceptos, los métodos y los marcos de referencia del estudio de la sociedad. Siguiendo las huellas de los clásicos, sus intereses teóricos lo llevaron por los más diversos campos del análisis social con una mente abierta, lo cual lo llevó a incursionar en casi todas las especialidades de la Sociología. Los trabajos de Merton sobre la anomia, la estructura burocrática y las relaciones de la ciencia con el orden social dieron lugar al desarrollo de campos específicos del análisis social. En América Latina como en el resto del mundo su influencia en el desarrollo de la Sociología se ha hecho sentir a pesar de haber sido relegada con la irrupción del marxismo a finales de los años sesenta y comienzos de los setenta. Su ejemplo se ha convertido en modelo de rol para generaciones enteras de analistas sociales, en el patrón a seguir por quienes eligen la Sociologías como una ocupación vocacionalmente orientada.

  16. Robert K. Merton

    Directory of Open Access Journals (Sweden)

    Gonzalo Cataño

    2006-01-01

    Full Text Available El 23 de febrero de 2003 murió en la ciudad de Nueva York el sociólogo norteamericano Robert King Merton. Teniendo presente que no es fácil resumir en unas pocas páginas la obra de quien se dedicó durante 66 años del siglo XX a una intensa actividad teórica y docente en Sociología, el artículo sintetiza algunos de los rasgos mas sobresalientes de su extensa obra. Su carrera académica se desarrolló a partir del legado de las figuras de la tradición sociológica europea y norteamericana que habían afirmado de manera definitiva los conceptos, los métodos y los marcos de referencia del estudio de la sociedad. Siguiendo las huellas de los clásicos, sus intereses teóricos lo llevaron por los más diversos campos del análisis social con una mente abierta, lo cual lo llevó a incursionar en casi todas las especialidades de la Sociología. Los trabajos de Merton sobre la anomia, la estructura burocrática y las relaciones de la ciencia con el orden social dieron lugar al desarrollo de campos específicos del análisis social. En América Latina como en el resto del mundo su influencia en el desarrollo de la Sociología se ha hecho sentir a pesar de haber sido relegada con la irrupción del marxismo a finales de los años sesenta y comienzos de los setenta. Su ejemplo se ha convertido en modelo de rol para generaciones enteras de analistas sociales, en el patrón a seguir por quienes eligen la Sociologías como una ocupación vocacionalmente orientada.

  17. Muscular Dystrophy (MD)

    Science.gov (United States)

    ... Awards Enhancing Diversity Find People About NINDS NINDS Muscular Dystrophy Information Page Clinical Trials Finding the Optimum Regimen ... en Español Additional resources from MedlinePlus What is Muscular Dystrophy? The muscular dystrophies (MD) are a group of ...

  18. Square Roots of -1 in Real Clifford Algebras

    CERN Document Server

    Hitzer, Eckhard; Ablamowicz, Rafal

    2012-01-01

    It is well known that Clifford (geometric) algebra offers a geometric interpretation for square roots of -1 in the form of blades that square to minus 1. This extends to a geometric interpretation of quaternions as the side face bivectors of a unit cube. Systematic research has been done [1] on the biquaternion roots of -1, abandoning the restriction to blades. Biquaternions are isomorphic to the Clifford (geometric) algebra $Cl(3,0)$ of $\\mathbb{R}^3$. Further research on general algebras $Cl(p,q)$ has explicitly derived the geometric roots of -1 for $p+q \\leq 4$ [2]. The current research abandons this dimension limit and uses the Clifford algebra to matrix algebra isomorphisms in order to algebraically characterize the continuous manifolds of square roots of -1 found in the different types of Clifford algebras, depending on the type of associated ring ($\\mathbb{R}$, $\\mathbb{H}$, $\\mathbb{R}^2$, $\\mathbb{H}^2$, or $\\mathbb{C}$). At the end of the paper explicit computer generated tables of representative sq...

  19. 'Twisted duality' in the ${\\rm C^*}$ Clifford algebra

    OpenAIRE

    Robinson, P. L.

    2014-01-01

    Let $V$ be a real inner product space and $C[V]$ its ${\\rm C}^*$ Clifford algebra. We prove that if $Z$ is a subspace of $V$ then $C[Z^{\\perp}]$ coincides with the supercommutant of $C[Z]$ in $C[V]$.

  20. Algebraic spinor spaces in the Clifford algebras of Minkowski spaces

    International Nuclear Information System (INIS)

    Algebraic spinor spaces in the Clifford algebras of two- and four-dimensional Minkowski spaces are considered. Their description in terms of primitive idempotens and their classification with respect to the action of the Lorentz group are given. (author). 6 refs

  1. The $E_8$ geometry from a Clifford perspective

    CERN Document Server

    Dechant, Pierre-Philippe

    2016-01-01

    This paper considers the geometry of $E_8$ from a Clifford point of view in three complementary ways. Firstly, in earlier work, I had shown how to construct the four-dimensional exceptional root systems from the 3D root systems using Clifford techniques, by constructing them in the 4D even subalgebra of the 3D Clifford algebra; for instance the icosahedral root system $H_3$ gives rise to the largest (and therefore exceptional) non-crystallographic root system $H_4$. Arnold's trinities and the McKay correspondence then hint that there might be an indirect connection between the icosahedron and $E_8$. Secondly, in a related construction, I have now made this connection explicit for the first time: in the 8D Clifford algebra of 3D space the $120$ elements of the icosahedral group $H_3$ are doubly covered by $240$ 8-component objects, which endowed with a `reduced inner product' are exactly the $E_8$ root system. It was previously known that $E_8$ splits into $H_4$-invariant subspaces, and we discuss the folding ...

  2. Fractional Dirac operators and deformed field theory on Clifford algebra

    International Nuclear Information System (INIS)

    Fractional Dirac equations are constructed and fractional Dirac operators on Clifford algebra in four dimensional are introduced within the framework of the fractional calculus of variations recently introduced by the author. Many interesting consequences are revealed and discussed in some details.

  3. Categorification of Clifford algebra via geometric induction and restriction

    OpenAIRE

    Gruson, Caroline; Serganova, Vera

    2016-01-01

    We use geometric parabolic induction functors and the adjoint functors for the supergroups Osp(2m+1,2n) (where m and n vary) to categorify the action of the infinite-dimensional Clifford algebra on the Fock space of semi-infinite forms.

  4. Matrix solutions of wave equations and Clifford algebras

    International Nuclear Information System (INIS)

    We are extending the formation of matrix solutions un for linear and nonlinear wave equations by construction of unitary anti-Hermitian-anti-commuting matrices up to the eighth order. We use Clifford algebras C(0,n) with periodicity in modulo 8 to construct coupled matrix solutions. We also propose to use the matrix solutions for describing the intrinsic rotations of particles. (author)

  5. On the representation of generalized Dirac (Clifford) algebras

    International Nuclear Information System (INIS)

    Some results of Brauer and Weyl and of Jordan and Wigner on irreducible representations of generalized Dirac (Clifford) algebras have been proved, adopting a new and simple approach which (i) makes the whole subject straight-forward for physicists and (ii) simplifies the demonstration of the fundamental theorem of Pauli. (Auth.)

  6. Modulo 8 periodicity of real Clifford algebras and particle physics

    International Nuclear Information System (INIS)

    After a review of the properties of real Clifford algebras, we discuss the isomorphism existing between these algebras and matrix algebras over the real, complex or quaternion field. This is done for all dimensions and all possible signatures of the metric. The modulo 8 periodicity theorem is discussed and extended. A comment is made about the appearance of 'hidden' symmetries in supergravity theories. (orig.)

  7. Collide and Squeeze MD

    CERN Document Server

    Gorzawski, Arkadiusz; Papotti, Giulia; Salvachua Ferrando, Belen Maria; Wenninger, Jorg; Pieloni, Tatiana; CERN. Geneva. ATS Department

    2015-01-01

    Colliding the beams during the squeeze to profit from Landau damping due to head--on beam-beam and b* leveling are two operational modes that may have to be used in a not so distant future at the LHC. This MD aimed at improving the process control during the squeeze with much improved handling of reference for the orbit feedback system and at evaluating instruments and techniques to maintain the beam in collisions with active feedback on a good observable.

  8. 75 FR 26993 - Alvin Darby, M.D.; Denial of Application

    Science.gov (United States)

    2010-05-13

    ... dependency on crack cocaine and `primo,' a mixture of cocaine and marijuana smoked together.'' GX 3, at 2... factors are * * * considered in the disjunctive.'' Robert A. Leslie, M.D., 68 FR 15227, 15230 (2003). I... application under section 303. See The Lawsons, Inc., 72 FR 74334, 74337 (2007); Anthony D. Funches, 64...

  9. 78 FR 76322 - Thomas Neuschatz, M.D.; Decision and Order

    Science.gov (United States)

    2013-12-17

    ... of J.G.'s known addiction, ``but inaccurately represented this as a treatment for a chronic pain... her chronic pain rather than as treatment for her opioid addiction was patently false.'' Id. at 18...(f). ``These factors are . . . considered in the disjunctive.'' Robert A. Leslie, M.D., 68 FR...

  10. Clifford algebras geometric modelling and chain geometries with application in kinematics

    CERN Document Server

    Klawitter, Daniel

    2015-01-01

    After revising known representations of the group of Euclidean displacements Daniel Klawitter gives a comprehensive introduction into Clifford algebras. The Clifford algebra calculus is used to construct new models that allow descriptions of the group of projective transformations and inversions with respect to hyperquadrics. Afterwards, chain geometries over Clifford algebras and their subchain geometries are examined. The author applies this theory and the developed methods to the homogeneous Clifford algebra model corresponding to Euclidean geometry. Moreover, kinematic mappings for special Cayley-Klein geometries are developed. These mappings allow a description of existing kinematic mappings in a unifying framework.  Contents Models and representations of classical groups Clifford algebras, chain geometries over Clifford algebras Kinematic mappings for Pin and Spin groups Cayley-Klein geometries Target Groups Researchers and students in the field of mathematics, physics, and mechanical engineering About...

  11. Steven Hawking with Robert Aymar

    CERN Multimedia

    Maximilien Brice

    2006-01-01

    Steven Hawking is seen meeting with CERN's Director-General, Robert Aymar. Hawking visited CERN between 24 September and 1 October 2006. During his stay he gave two lectures and toured the LHC, which may provide insights into Hawking's most famous area of study, black holes.

  12. Clifford algebra-valued orthogonal polynomials in the open unit ball of Euclidean space

    OpenAIRE

    Fred Brackx; Nele De Schepper; Frank Sommen

    2004-01-01

    A new method for constructing Clifford algebra-valued orthogonal polynomials in the open unit ball of Euclidean space is presented. In earlier research, we only dealt with scalar-valued weight functions. Now the class of weight functions involved is enlarged to encompass Clifford algebra-valued functions. The method consists in transforming the orthogonality relation on the open unit ball into an orthogonality relation on the real axis by means of the so-called Clifford-Heaviside functions. C...

  13. Riemann surfaces, Clifford algebras and infinite dimensional groups

    International Nuclear Information System (INIS)

    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.)

  14. m-Qubit states embedded in Clifford algebras CL2m

    International Nuclear Information System (INIS)

    The quantum theory of a finite quantum system with L degrees of freedom is usually set up by associating it with a Hilbert space H of dimension d(L) and identifying observables and states in the matrix algebra Md(C). For the case d = 2m, m integer, this algebra can be identified with the Clifford algebra CL2m. The case of d = 2m dimensions is simply realized by a system with m dichotomic degrees of freedom, an m-qubit system for instance. The physically relevant new point is the appearance of a new (symmetry-?)group SO(2m). A possible interpretation of the space in which this group operates is proposed. It is shown that the eigenvalues of m-qubit-type states only depend on SO(2m)-invariants. We use this fact to determine state parameter domains (generalized Bloch spheres) for states classified as SO(2m)-tensors. The classification of states and interactions of components of a physical m-qubit system as k-tensors and pseudotensors (0 ≤ k ≤ m) leads to rules similar to those found in elementary quantum mechanics. The question of electromagnetic interactions is shortly broached. We sketch, pars pro toto, a graphical interpretation of tensor contractions appearing in perturbative expansions

  15. $Z_3$-graded analogues of Clifford algebras and generalization of supersymmetry

    OpenAIRE

    Abramov, V.

    1996-01-01

    We define and study the ternary analogues of Clifford algebras. It is proved that the ternary Clifford algebra with $N$ generators is isomorphic to the subalgebra of the elements of grade zero of the ternary Clifford algebra with $N+1$ generators. In the case $N=3$ the ternary commutator of cubic matrices induced by the ternary commutator of the elements of grade zero is derived. We apply the ternary Clifford algebra with one generator to construct the $Z_3$-graded generalization of the simpl...

  16. Lie algebras for the Dirac-Clifford ring

    International Nuclear Information System (INIS)

    It is shown in a general way that the Dirac-Clifford ring formed by the Dirac matrices and all their products, for all even and odd spacetime dimensions D, span the cumulation algebras SU(2D/2) for even D and SU(2(D-1)/2) + SU(2(D-1)/2) for odd D. Some physical consequences of these results are discussed. (author)

  17. Reflections in Conics, Quadrics and Hyperquadrics via Clifford Algebra

    OpenAIRE

    Klawitter, Daniel

    2014-01-01

    In this article we present a new and not fully employed geometric algebra model. With this model a generalization of the conformal model is achieved. We discuss the geometric objects that can be represented. Furthermore, we show that the Pin group of this geometric algebra corresponds to inversions with respect to axis aligned quadrics. We discuss the construction for the two- and three-dimensional case in detail and give the construction for arbitrary dimension. Key Words: Clifford algebra, ...

  18. A satisfactory formalism for magnetic monopoles by Clifford algebras

    International Nuclear Information System (INIS)

    The problem of electromagnetism with magnetic monopoles is approached by the physically interesting and mathematically powerful formalism of Clifford algebras, which provides a natural language for Minkowski space-time (Dirac algebra) and euclidean space (Pauli algebra). A lagrangian and hamiltonian formalism is constructed for interacting monopoles, which overcomes many of the long-standing difficulties that are known to plague the approaches developed till now. (orig.)

  19. Unified theories for quarks and leptons based on Clifford algebras

    International Nuclear Information System (INIS)

    The general standpoint is presented that unified theories arise from gauging of Clifford algebras describing the internal degrees of freedom (charge, color, generation, spin) of the fundamental fermions. The general formalism is presented and the ensuing theories for color and charge (with extension to N colors), and for generations, are discussed. The possibility of further including the spin is discussed, also in connection with generations. (orig.)

  20. Clifford algebra and solution of Bargmann-Michel-Telegdi equation

    International Nuclear Information System (INIS)

    The Clifford algebra structure of the Minkowski space is presented in the article. The method of solving motion equations within the frames of formalism of this algebra is described. The solution of the spin motion equation (the Bargmann-Michel-Telegdi equations) is obtained by means of the plotted algorithm for the case of the magnetic gyroscope motion in the constant and homogenous electromagnetic field

  1. Hochschild Cohomology and Deformations of Clifford-Weyl Algebras

    Directory of Open Access Journals (Sweden)

    Ian M. Musson

    2009-03-01

    Full Text Available We give a complete study of the Clifford-Weyl algebra C(n,2k from Bose-Fermi statistics, including Hochschild cohomology (with coefficients in itself. We show that C(n,2k is rigid when n is even or when k ≠ 1. We find all non-trivial deformations of C(2n+1,2 and study their representations.

  2. Quantum spinors and spin groups from quantum Clifford algebras

    International Nuclear Information System (INIS)

    A general construction of multiparametric quantum spinors and corresponding quantum Spinμ(2ν-h,h) groups associated to 2ν-(Pseudo)-Euclidean spaces is presented, and their homomorphism to the respective SOμ groups is discussed. This construction is based on a quantum Clifford algebra and is described in detail for involutive (pure twists) intertwining braids. For general braid operators that admit abstract 'volume elements', a procedure is also given for deriving quantum analogues of these groups. (author)

  3. Clifford support vector machines for classification, regression, and recurrence.

    Science.gov (United States)

    Bayro-Corrochano, Eduardo Jose; Arana-Daniel, Nancy

    2010-11-01

    This paper introduces the Clifford support vector machines (CSVM) as a generalization of the real and complex-valued support vector machines using the Clifford geometric algebra. In this framework, we handle the design of kernels involving the Clifford or geometric product. In this approach, one redefines the optimization variables as multivectors. This allows us to have a multivector as output. Therefore, we can represent multiple classes according to the dimension of the geometric algebra in which we work. We show that one can apply CSVM for classification and regression and also to build a recurrent CSVM. The CSVM is an attractive approach for the multiple input multiple output processing of high-dimensional geometric entities. We carried out comparisons between CSVM and the current approaches to solve multiclass classification and regression. We also study the performance of the recurrent CSVM with experiments involving time series. The authors believe that this paper can be of great use for researchers and practitioners interested in multiclass hypercomplex computing, particularly for applications in complex and quaternion signal and image processing, satellite control, neurocomputation, pattern recognition, computer vision, augmented virtual reality, robotics, and humanoids. PMID:20876017

  4. Robert Zajonc: The Complete Psychologist

    OpenAIRE

    Berridge, Kent C.

    2010-01-01

    This article joins with others in the same issue to celebrate the career of Robert B. Zajonc who was a broad, as well as deeply talented, psychologist. Beyond his well-known focus in social psychology, the work of Zajonc also involved, at one time or another, forays into nearly every other subfield of psychology. This article focuses specifically on his studies that extended into biopsychology, which deserve special highlighting in order to be recognized alongside his many major achievements ...

  5. Two-sided Clifford Fourier transform with two square roots of -1 in Cl(p,q)

    OpenAIRE

    Hitzer, Eckhard

    2013-01-01

    We generalize quaternion and Clifford Fourier transforms to general two-sided Clifford Fourier transforms (CFT), and study their properties (from linearity to convolution). Two general \\textit{multivector square roots} $\\in \\cl{p,q}$ \\textit{of} -1 are used to split multivector signals, and to construct the left and right CFT kernel factors. Keywords: Clifford Fourier transform, Clifford algebra, signal processing, square roots of -1 .

  6. Development of the method of quaternion typification of Clifford algebra elements using k-fold commutators and anticommutators

    OpenAIRE

    Shirokov, Dmitry

    2009-01-01

    In this paper we further develop the method of quaternion typification of Clifford algebra elements suggested by the author in the previous paper. On the basis of new classification of Clifford algebra elements it is possible to find out and prove a number of new properties of Clifford algebra. We use k-fold commutators and anticommutators.

  7. The Application of Aristotle's Theory of Tragedy in the Analysis of Clifford

    Institute of Scientific and Technical Information of China (English)

    陈美林

    2005-01-01

    Clifford, a wealthy but paralyzed baronet, is always criticized without any compromise and is regarded hypocritical, cruel, in a word, a half-human and half-machine monster. However, the author believes that Clifford is a tragic character. This paper will analyze this character according to Aristotle's theory on tragedy, which is presented in his masterpiece Poetics.

  8. The Riesz-Clifford Functional Calculus for Non-Commuting Operators and Quantum Field Theory

    OpenAIRE

    Kisil, Vladimir V.; de Arellano, Enrique Ramírez

    1995-01-01

    We present a Riesz-like hyperholomorphic functional calculus for a set of non-commuting operators based on the Clifford analysis. Applications to the quantum field theory are described. Keywords: Functional calculus, Weyl calculus, Riesz calculus, Clifford analysis, quantization, quantum field theory. AMSMSC Primary:47A60, Secondary: 81T10

  9. A GENERALIZED WINDOWED FOURIER TRANSFORM IN REAL CLIFFORD ALGEBRA CL0;N

    OpenAIRE

    Bahri, Mawardi

    2011-01-01

    The Clifford Fourier transform in Cl0;n (CFT) can be regarded as a generalization of the two-dimensional quaternionic Fourier transform (QFT), which is introduced from the mathematical aspect by Brackx at first. In this research paper, we propose the Clifford windowed Fourier transform using the kernel of the CFT. Some important properties of the transform are investigated.

  10. A classification of Lie algebras of pseudounitary groups in the techniques of Clifford algebras

    OpenAIRE

    Shirokov, Dmitry

    2007-01-01

    In this paper we present new formulas, which represent commutators and anticommutators of Clifford algebra elements as sums of elements of different ranks. Using these formulas we consider subalgebras of Lie algebras of pseudounitary groups. Our main techniques are Clifford algebras. We have find 12 types of subalgebras of Lie algebras of pseudounitary groups.

  11. The Hidden Quantum Group of the 8-vertex Free Fermion Model: q-Clifford Algebras

    OpenAIRE

    Cuerno, Rodolfo; Gómez, César; López Manzanares, Esperanza; Sierra, Germán

    1993-01-01

    We prove in this paper that the elliptic $R$--matrix of the eight vertex free fermion model is the intertwiner $R$--matrix of a quantum deformed Clifford--Hopf algebra. This algebra is constructed by affinization of a quantum Hopf deformation of the Clifford algebra.

  12. Between Quantum Virasoro Algebra \\cal{L}_c and Generalized Clifford Algebras

    OpenAIRE

    Kinani, E. H. El

    2003-01-01

    In this paper we construct the quantum Virasoro algebra ${\\mathcal{L}}_{c}$ generators in terms of operators of the generalized Clifford algebras $C_{n}^{k}$. Precisely, we show that ${\\mathcal{L}}_{c}$ can be embedded into generalized Clifford algebras.

  13. Real Clifford Algebra Cln,0, n = 2, 3(mod 4) Wavelet Transform

    International Nuclear Information System (INIS)

    We show how for n = 2, 3(mod 4) continuous Clifford (geometric) algebra (GA)Cln-valued admissible wavelets can be constructed using the similitude group SIM(n). We strictly aim for real geometric interpretation, and replace the imaginary unit i is an element of C therefore with a GA blade squaring to -1. Consequences due to non-commutativity arise. We express the admissibility condition in terms of a Cln Clifford Fourier Transform and then derive a set of important properties such as dilation, translation and rotation covariance, a reproducing kernel, and show how to invert the Clifford wavelet transform. As an example, we introduce Clifford Gabor wavelets. We further invent a generalized Clifford wavelet uncertainty principle.

  14. THE DEMOKTESIS OF ROBERT NOZICK A DEMOKTESIS DE ROBERT NOZICK

    Directory of Open Access Journals (Sweden)

    Luiz Felipe Netto de Andrade e Silva Sahd

    2008-04-01

    Full Text Available the present article aims at reconstructing Robert Nozick’s cen-tral arguments about the extreme positions held by North American li-bertarians who do not distinguish between Welfare state and totalitarian state. Despite divergences on a pivotal question, that of the state, there are some affinities between Nozick and this current of thought. Contrary to the anarchist theory, the Minimal state is preferable to the state of nature as described by John locke.O presente artigo tem como objetivo reconstruir argumentos cen-trais, desenvolvidos por Robert Nozick, acerca das posições extremas que não diferenciam Estado-providência e Estado totalitário na política dos libertarianos norte-americanos, isto é, sobre as afinidades percebidas por Nozick com as teses desta corrente de pensamento, embora se afastando num ponto essencial: a questão do Estado. Ao contrário da teoria anar-quista, o Estado mínimo é preferível ao estado de natureza, tal como John locke o descreve.

  15. ADT fast losses MD

    CERN Document Server

    Priebe, A; Dehning, B; Redaelli, S; Salvachua Ferrando, BM; Sapinski, M; Solfaroli Camillocci, M; Valuch, D

    2013-01-01

    The fast beam losses in the order of 1 ms are expected to be a potential major luminosity limitation for higher beam energies after the LHC long shutdown (LS1). Therefore a Quench Test is planned in the winter 2013 to estimate the quench limit in this timescale and revise the current models. This experiment was devoted to determination the LHC Transverse Damper (ADT) as a system for fast losses induction. A non-standard operation of the ADT was used to develop the beam oscillation instead of suppressing them. The sign flip method had allowed us to create the fast losses within several LHC turns at 450 GeV during the previous test (26th March 2012). Thus, the ADT could be potentially used for the studies of the UFO ("Unidentied Falling Object") impact on the cold magnets. Verification of the system capability and investigations of the disturbed beam properties were the main objectives of this MD. During the experiment, the pilot bunches of proton beam were excited independently in the horizontal and vertical ...

  16. Connections on Clifford bundles and the Dirac operator

    International Nuclear Information System (INIS)

    It is shown, how - in the setting of Clifford bundles - the spin connection (or Dirac operator) may be obtained by averaging the Levi-Civita connection (or Kaehler-Dirac operator) over the finite group generated by an orthonormal frame of the base-manifold. The familiar covariance of the Dirac equation under a simultaneous transformation of spinors and matrix-representations emerges very naturally in this scheme, which can also be applied when the manifold does not possess a spin-structure. (Author)

  17. Local unitary versus local Clifford equivalence of stabilizer states

    International Nuclear Information System (INIS)

    We study the relation between local unitary (LU) equivalence and local Clifford (LC) equivalence of stabilizer states. We introduce a large subclass of stabilizer states, such that every two LU equivalent states in this class are necessarily LC equivalent. Together with earlier results, this shows that LC, LU, and stochastic local operation with classical communication equivalence are the same notions for this class of stabilizer states. Moreover, recognizing whether two given stabilizer states in the present subclass are locally equivalent only requires a polynomial number of operations in the number of qubits

  18. Galilean-covariant Clifford algebras in the phase space representation

    International Nuclear Information System (INIS)

    We apply the Galilean covariant formulation of quantum dynamics to derive the phase-space representation of the Pauli-Schroedinger equation for the density matrix of spin-1/2 particles in the presence of an electromagnetic field. The Liouville operator for the particle with spin follows from using the Wigner-Moyal transformation and a suitable Clifford algebra constructed on the phase space of a (4+1)-dimensional spacetime with Galilean geometry. Connections with the algebraic formalism of thermofield dynamics are also investigated. (author)

  19. Relativistic Electrodynamics without Reference Frames. Clifford Algebra Formulation

    OpenAIRE

    Ivezic, Tomislav

    2002-01-01

    In the usual Clifford algebra formulation of electrodynamics the Faraday bivector field $F$ is expressed in terms of \\QTR{em}{the observer dependent} relative vectors $\\QTR{bf}{E}$ and $\\QTR{bf}{B.}$ In this paper we present \\QTR{em}{the observer independent}decomposition of $F$ by using the vectors (grade-1) of electric $E$ and magnetic $B$ fields and we develop the formulation of relativistic electrodynamics which is independent of the reference frame and of the chosen coordinatization. We ...

  20. MD5算法研究%MD5 Algorithm

    Institute of Scientific and Technical Information of China (English)

    张裔智; 赵毅; 汤小斌

    2008-01-01

    随着网络技术的迅速发展,信息加密技术已成为保障网络安全的一种重要手段,加密算法已经成为人们的一个研究热点.本文对MD5算法进行了深入研究,介绍MD5算法的产生背景、应用及其算法流程,并提出了MD5算法的一个改进方案.

  1. Bilinear covariants and spinor fields duality in quantum Clifford algebras

    Science.gov (United States)

    Abłamowicz, Rafał; Gonçalves, Icaro; da Rocha, Roldão

    2014-10-01

    Classification of quantum spinor fields according to quantum bilinear covariants is introduced in a context of quantum Clifford algebras on Minkowski spacetime. Once the bilinear covariants are expressed in terms of algebraic spinor fields, the duality between spinor and quantum spinor fields can be discussed. Thus, by endowing the underlying spacetime with an arbitrary bilinear form with an antisymmetric part in addition to a symmetric spacetime metric, quantum algebraic spinor fields and deformed bilinear covariants can be constructed. They are thus compared to the classical (non quantum) ones. Classes of quantum spinor fields classes are introduced and compared with Lounesto's spinor field classification. A physical interpretation of the deformed parts and the underlying {Z}-grading is proposed. The existence of an arbitrary bilinear form endowing the spacetime already has been explored in the literature in the context of quantum gravity [S. W. Hawking, "The unpredictability of quantum gravity," Commun. Math. Phys. 87, 395 (1982)]. Here, it is shown further to play a prominent role in the structure of Dirac, Weyl, and Majorana spinor fields, besides the most general flagpoles and flag-dipoles. We introduce a new duality between the standard and the quantum spinor fields, by showing that when Clifford algebras over vector spaces endowed with an arbitrary bilinear form are taken into account, a mixture among the classes does occur. Consequently, novel features regarding the spinor fields can be derived.

  2. Topological classification with additional symmetries from Clifford algebras

    Science.gov (United States)

    Morimoto, Takahiro; Furusaki, Akira

    2013-09-01

    We classify topological insulators and superconductors in the presence of additional symmetries such as reflection or mirror symmetries. For each member of the 10 Altland-Zirnbauer symmetry classes, we have a Clifford algebra defined by operators of the generic (time-reversal, particle-hole, or chiral) symmetries and additional symmetries, together with gamma matrices in Dirac Hamiltonians representing topological insulators and superconductors. Following Kitaev's approach, we classify gapped phases of noninteracting fermions under additional symmetries by examining all possible distinct Dirac mass terms which can be added to the set of generators of the Clifford algebra. We find that imposing additional symmetries in effect changes symmetry classes and causes shifts in the periodic table of topological insulators and superconductors. Our results are in agreement with the classification under reflection symmetry recently reported by Chiu, Yao, and Ryu [Phys. Rev. B1098-012110.1103/PhysRevB.88.075142 88, 075142 (2013)]. Several examples are discussed including a topological crystalline insulator with mirror Chern numbers and mirror superconductors.

  3. Bilinear covariants and spinor fields duality in quantum Clifford algebras

    International Nuclear Information System (INIS)

    Classification of quantum spinor fields according to quantum bilinear covariants is introduced in a context of quantum Clifford algebras on Minkowski spacetime. Once the bilinear covariants are expressed in terms of algebraic spinor fields, the duality between spinor and quantum spinor fields can be discussed. Thus, by endowing the underlying spacetime with an arbitrary bilinear form with an antisymmetric part in addition to a symmetric spacetime metric, quantum algebraic spinor fields and deformed bilinear covariants can be constructed. They are thus compared to the classical (non quantum) ones. Classes of quantum spinor fields classes are introduced and compared with Lounesto's spinor field classification. A physical interpretation of the deformed parts and the underlying Z-grading is proposed. The existence of an arbitrary bilinear form endowing the spacetime already has been explored in the literature in the context of quantum gravity [S. W. Hawking, “The unpredictability of quantum gravity,” Commun. Math. Phys. 87, 395 (1982)]. Here, it is shown further to play a prominent role in the structure of Dirac, Weyl, and Majorana spinor fields, besides the most general flagpoles and flag-dipoles. We introduce a new duality between the standard and the quantum spinor fields, by showing that when Clifford algebras over vector spaces endowed with an arbitrary bilinear form are taken into account, a mixture among the classes does occur. Consequently, novel features regarding the spinor fields can be derived

  4. Bilinear covariants and spinor fields duality in quantum Clifford algebras

    Energy Technology Data Exchange (ETDEWEB)

    Abłamowicz, Rafał, E-mail: rablamowicz@tntech.edu [Department of Mathematics, Box 5054, Tennessee Technological University, Cookeville, Tennessee 38505 (United States); Gonçalves, Icaro, E-mail: icaro.goncalves@ufabc.edu.br [Instituto de Matemática e Estatística, Universidade de São Paulo, Rua do Matão, 1010, 05508-090, São Paulo, SP (Brazil); Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, 09210-170 Santo André, SP (Brazil); Rocha, Roldão da, E-mail: roldao.rocha@ufabc.edu.br [Centro de Matemática, Computação e Cognição, Universidade Federal do ABC, 09210-170 Santo André, SP (Brazil); International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste (Italy)

    2014-10-15

    Classification of quantum spinor fields according to quantum bilinear covariants is introduced in a context of quantum Clifford algebras on Minkowski spacetime. Once the bilinear covariants are expressed in terms of algebraic spinor fields, the duality between spinor and quantum spinor fields can be discussed. Thus, by endowing the underlying spacetime with an arbitrary bilinear form with an antisymmetric part in addition to a symmetric spacetime metric, quantum algebraic spinor fields and deformed bilinear covariants can be constructed. They are thus compared to the classical (non quantum) ones. Classes of quantum spinor fields classes are introduced and compared with Lounesto's spinor field classification. A physical interpretation of the deformed parts and the underlying Z-grading is proposed. The existence of an arbitrary bilinear form endowing the spacetime already has been explored in the literature in the context of quantum gravity [S. W. Hawking, “The unpredictability of quantum gravity,” Commun. Math. Phys. 87, 395 (1982)]. Here, it is shown further to play a prominent role in the structure of Dirac, Weyl, and Majorana spinor fields, besides the most general flagpoles and flag-dipoles. We introduce a new duality between the standard and the quantum spinor fields, by showing that when Clifford algebras over vector spaces endowed with an arbitrary bilinear form are taken into account, a mixture among the classes does occur. Consequently, novel features regarding the spinor fields can be derived.

  5. Clifford Space as a Generalization of Spacetime: Prospects for Unification in Physics

    OpenAIRE

    Pavsic, Matej

    2004-01-01

    The geometric calculus based on Clifford algebra is a very useful tool for geometry and physics. It describes a geometric structure which is much richer than the ordinary geometry of spacetime. A Clifford manifold ($C$-space) consists not only of points, but also of 1-loops, 2-loops, etc.. They are associated with multivectors which are the wedge product of the basis vectors, the generators of Clifford algebra. We assume that $C$-space is the true space in which physics takes place and that p...

  6. Structure of inverse elements of Clifford algebra of dimension at most two to the fifth power

    OpenAIRE

    Suzuki, Yuka; Yamaguchi, Naoya

    2016-01-01

    A Clifford algebra of two to the fifth power dimension is applicable to computer graphics. In particular, one needs to compute inverse elements of the Clifford algebra. The inverse formulas for elements of Clifford algebras of dimensions less than or equal to two the fifth power are known by direct calculation. The formulas have some structure. However, we did not know the reason for the formulas have the structure. In this paper, we give the reason by some anti-isomorphisms on subspaces of C...

  7. 78 FR 14547 - Praxedes E. Alverez Santiago, M.D., Daniel Perez Brisebois, M.D., Jorge Grillasca Palou, M.D...

    Science.gov (United States)

    2013-03-06

    ... Praxedes E. Alverez Santiago, M.D., Daniel Perez Brisebois, M.D., Jorge Grillasca Palou, M.D., Rafael Garcia Nieves, M.D., Francis M. Vazques Roura, M.D., Angel B. Rivera Santos, M.D., Cosme D. Santos Torres, M.D., and Juan L. Vilaro Chardon, M.D.; Analysis of Agreement Containing Consent Order To Aid...

  8. The many faces of Maxwell, Dirac and Einstein equations a Clifford bundle approach

    CERN Document Server

    Rodrigues, Jr, Waldyr A

    2016-01-01

    This book is an exposition of the algebra and calculus of differential forms, of the Clifford and Spin-Clifford bundle formalisms, and of vistas to a formulation of important concepts of differential geometry indispensable for an in-depth understanding of space-time physics. The formalism discloses the hidden geometrical nature of spinor fields. Maxwell, Dirac and Einstein fields are shown to have representatives by objects of the same mathematical nature, namely sections of an appropriate Clifford bundle. This approach reveals unity in diversity and suggests relationships that are hidden in the standard formalisms and opens new paths for research. This thoroughly revised second edition also adds three new chapters: on the Clifford bundle approach to the Riemannian or semi-Riemannian differential geometry of branes; on Komar currents in the context of the General Relativity theory; and an analysis of the similarities and main differences between Dirac, Majorana and ELKO spinor fields. The exercises with solut...

  9. Minimal surfaces in the three-Sphere by doubling the Clifford Torus

    OpenAIRE

    Kapouleas, Nicolaos; Yang, Seong-Deog

    2007-01-01

    We construct embedded closed minimal surfaces in the round three-sphere, resembling two parallel copies of the Clifford torus, joined by m^2 small catenoidal bridges symmetrically arranged along a square lattice of points on the torus.

  10. ON CAUCHY-POMPEIU FORMULA FOR FUNCTIONS WITH VALUES IN A UNIVERSAL CLIFFORD ALGEBRA

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    This paper obtains the Cauchy-Pompeiu formula on certain distinguishedboundary for functions with values in a universal Clifford algebra. This formula is just anextension of the Cauchy's integral formula obtained in [11].

  11. A list of identities made with products between two different generators of the Clifford algebra

    OpenAIRE

    Formiga, J. B.

    2012-01-01

    Here I present a full list with all possibles products between the generators of the Clifford algebra in a four-dimensional spacetime. The resulting expressions turned out to be very simple and easy to deal with.

  12. A new description of space and time using Clifford multivectors

    CERN Document Server

    Chappell, James M; Iqbal, Azhar; Abbott, Derek

    2012-01-01

    Following the development of the special theory of relativity in 1905, Minkowski sought to provide a physical basis for Einstein's two fundamental postulates of special relativity, proposing a four dimensional spacetime structure consisting of three space and one time dimension, with the relativistic effects then being straightforward consequences of this spacetime geometry. As an alternative to Minkowski's approach, we produce the results of special relativity directly from three space ($ \\Re_3 $) without the addition of an extra dimension, through identifying the local time with the three rotational degrees of freedom of this space. The natural mathematical formalism within which to describe this definition of spacetime is found to be Clifford's geometric algebra, and specifically a three-dimensional multivector. With time now identified with the three rotational degrees of freedom of space, time becomes three-dimensional, which provides a natural symmetry between space and time in the form of a complex-typ...

  13. Quantum ring in the eyes of geometric (Clifford) algebra

    Science.gov (United States)

    Dargys, A.

    2013-01-01

    The quantum ring with spin-orbit interaction included is analyzed in a nonstandard way using Clifford or geometric algebra (GA). The solution of the Schrödinger-Pauli equation is presented in terms of rotors having clear classical mechanics interpretation, i.e., in GA the rotors act in 3D Euclidean space rather than as operators in an abstract Hilbert space. This classical-like property of spin control in GA provides a more transparent approach in designing and understanding spintronic devices. The aim of the paper is to attract readers attention to new possibilities in spin physics and to demonstrate how the quantum ring problem can be solved by GA methods.

  14. Bilinear Covariants and Spinor Fields Duality in Quantum Clifford Algebras

    CERN Document Server

    Ablamowicz, Rafal; da Rocha, Roldao

    2014-01-01

    Classification of quantum spinor fields according to quantum bilinear covariants is introduced in a context of quantum Clifford algebras on Minkowski spacetime. Once the bilinear covariants are expressed in terms of algebraic spinor fields, the duality between spinor and quantum spinor fields is thus discussed. Hence, by endowing the underlying spacetime with an arbitrary bilinear form with a antisymmetric part in addition to a symmetric spacetime metric, quantum algebraic spinor fields and deformed bilinear covariants can be constructed. They are therefore compared to the classical (non quantum) ones. Classes of quantum spinor fields are introduced and compared with Lounesto's spinor field classification. A physical interpretation of the deformed parts and the underlying Z-grading is proposed. The existence of an arbitrary bilinear form endowing the spacetime already has been explored in the literature in the context of quantum gravity. Here, it is shown further to play a prominent role in the structure of D...

  15. Elementary particle states based on the Clifford algebra C7

    International Nuclear Information System (INIS)

    The lepton isodoublet (e-,νsub(e)), the ''bare'' nucleon is isodoublet (n,p), and their antiparticles are shown to constitute a basis of the irreducible representation of the Clifford algebra C7. The excited states of these doublets, i.e., (μ-,νsub(μ)), (tau-,νsub(tau)),..., and (s0,c+),(b0,t+) are generated by the products (e-,νsub(e))sup(x)a and (n,p)sup(x)a, where a is identical to 2sup(-1/2)(e-e+ + νsub(e)ν-barsub(e)) has the same quantum numbers as the photon state. The bare baryons s,c,b,t carry the strangeness, charm, bottom, and top quantum numbers. These lepton and bare baryon states are in one-to-one correspondence with the integrally charged colored Han-Nambu quarks, and generate all the observed su(3) and su(4) hadron multiplets. (author)

  16. Magnetic monopoles without strings by Kaeler-Clifford algebra

    International Nuclear Information System (INIS)

    In substitution for Dirac monopoles with strings, we have recently introduced monopoles without string on the basis of a generalized potential, the sum of vector A and a psudovector *g*L5 B potential. By making recourse to the (graded) Clifford algebra, which just allows adding together tensors of different rank (e.g., scalars + psudoscalars + vectors + pseudovectors + ...), in a previous paper we succeeded in constructing a lagrangian and hamiltonian formalism for interacting monopoles that can be regarded as satisfactory from various points of view. In the present note, after having completed that formalism, we put forth a purely geometrical interpretation of it within the Kaeler algebra on differential forms, essential ingredients being the natural introduction of a generalized curvature and the Hodge decomposition. We thus pave the way for the extension of our monopoles without string to non-abelian gauge groups. The analogies of this approach with supersymmetric theories are apparent

  17. How to efficiently select an arbitrary Clifford group element

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, Robert [Institute for Quantum Computing and Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Smolin, John A. [IBM T.J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

    2014-12-15

    We give an algorithm which produces a unique element of the Clifford group on n qubits (C{sub n}) from an integer 0≤i<|C{sub n}| (the number of elements in the group). The algorithm involves O(n{sup 3}) operations and provides, in addition to a canonical mapping from the integers to group elements g, a factorization of g into a sequence of at most 4n symplectic transvections. The algorithm can be used to efficiently select random elements of C{sub n} which are often useful in quantum information theory and quantum computation. We also give an algorithm for the inverse map, indexing a group element in time O(n{sup 3})

  18. Magnetic monopoles without strings by Kaehler-Clifford algebra

    International Nuclear Information System (INIS)

    In place of Dirac monopoles with string, this paper presents monopoles without string on the basis of a generalized potential, the sum of a vector A and a pseudovector γB potential. By having recourse to the (graded) Clifford algebra which allows adding together tensors of different ranks (e.g., scalars + pseudoscalars + vectors + pseudovectors + . . .), in a previous paper we succeeded in constructing a Lagrangian and Hamiltonian formalism for interacting monopoles that can be regarded as satisfactory from various points of view. In the present note, after having completed that formalism, the authors put forth a purely geometrical interpretation of it within the Kahler algebra on differential forms, essential ingredients being the natural introduction of a generalized curvature and the Hodge decomposition. The authors thus pave the way for the extension of monopoles without string to non-abelian gauge groups. The analogies of this approach with supersymmetric theories are apparent

  19. Z2-gradings of Clifford algebras and multivector structures

    International Nuclear Information System (INIS)

    Let Cl(V, g) be the real Clifford algebra associated with the real vector space V, endowed with a nondegenerate metric g. In this paper, we study the class of Z2-gradings of Cl(V, g) which are somehow compatible with the multivector structure of the Grassmann algebra over V. A complete characterization for such Z2-gradings is obtained by classifying all the even subalgebras coming from them. An expression relating such subalgebras to the usual even part of Cl(V, g) is also obtained. Finally, we employ this framework to define spinor spaces, and to parametrize all the possible signature changes on Cl(V, g) by Z2-gradings of this algebra

  20. The Clifford algebra of physical space and Dirac theory

    Science.gov (United States)

    Vaz, Jayme, Jr.

    2016-09-01

    The claim found in many textbooks that the Dirac equation cannot be written solely in terms of Pauli matrices is shown to not be completely true. It is only true as long as the term β \\psi in the usual Dirac factorization of the Klein–Gordon equation is assumed to be the product of a square matrix β and a column matrix ψ. In this paper we show that there is another possibility besides this matrix product, in fact a possibility involving a matrix operation, and show that it leads to another possible expression for the Dirac equation. We show that, behind this other possible factorization is the formalism of the Clifford algebra of physical space. We exploit this fact, and discuss several different aspects of Dirac theory using this formalism. In particular, we show that there are four different possible sets of definitions for the parity, time reversal, and charge conjugation operations for the Dirac equation.

  1. Clifford algebra-based spatio-temporal modelling and analysis for complex geo-simulation data

    Science.gov (United States)

    Luo, Wen; Yu, Zhaoyuan; Hu, Yong; Yuan, Linwang

    2013-10-01

    The spatio-temporal data simulating Ice-Land-Ocean interaction of Antarctic are used to demonstrate the Clifford algebra-based data model construction, spatio-temporal query and data analysis. The results suggest that Clifford algebra provides a powerful mathematical tool for the whole modelling and analysis chains for complex geo-simulation data. It can also help implement spatio-temporal analysis algorithms more clearly and simply.

  2. Pauli theorem in the description of n-dimensional spinors in the Clifford algebra formalism

    Science.gov (United States)

    Shirokov, D. S.

    2013-04-01

    We discuss a generalized Pauli theorem and its possible applications for describing n-dimensional (Dirac, Weyl, Majorana, and Majorana-Weyl) spinors in the Clifford algebra formalism. We give the explicit form of elements that realize generalizations of Dirac, charge, and Majorana conjugations in the case of arbitrary space dimensions and signatures, using the notion of the Clifford algebra additional signature to describe conjugations. We show that the additional signature can take only certain values despite its dependence on the matrix representation

  3. On generalized Yang-Mills theories and extensions of the standard model in Clifford (tensorial) spaces

    International Nuclear Information System (INIS)

    We construct the Clifford-space tensorial-gauge fields generalizations of Yang-Mills theories and the Standard Model that allows to predict the existence of new particles (bosons, fermions) and tensor-gauge fields of higher-spins in the 10 Tev regime. We proceed with a detailed discussion of the unique D 4 - D 5 - E 6 - E 7 - E 8 model of Smith based on the underlying Clifford algebraic structures in D = 8, and which furnishes all the properties of the Standard Model and Gravity in four-dimensions, at low energies. A generalization and extension of Smith's model to the full Clifford-space is presented when we write explicitly all the terms of the extended Clifford-space Lagrangian. We conclude by explaining the relevance of multiple-foldings of D = 8 dimensions related to the modulo 8 periodicity of the real Cliford algebras and display the interplay among Clifford, Division, Jordan, and Exceptional algebras, within the context of D = 26, 27, 28 dimensions, corresponding to bosonic string, M and F theory, respectively, advanced earlier by Smith. To finalize we describe explicitly how the E 8 x E 8 Yang-Mills theory can be obtained from a Gauge Theory based on the Clifford (16) group

  4. Undergraduate Research at Oral Roberts University.

    Science.gov (United States)

    Couch, Richard; Thurman, Duane

    1981-01-01

    Explains Oral Roberts University's undergraduate requirement for research proficiency and how this requirement is fulfilled by biology majors. Topics of the required courses include: introduction to biological research; research techniques; independent research and senior paper; and senior seminar. (DS)

  5. Robert Walters named vice president for research

    OpenAIRE

    Trulove, Susan

    2007-01-01

    Robert Walters, interim associate vice president of research at Virginia Tech, has been named vice president for research effective immediately for a three-year period, announced Mark McNamee, university provost and vice president for academic affairs.

  6. Clifford Algebra Cℓ 3(ℂ) for Applications to Field Theories

    Science.gov (United States)

    Panicaud, B.

    2011-10-01

    The multivectorial algebras present yet both an academic and a technological interest. Difficulties can occur for their use. Indeed, in all applications care is taken to distinguish between polar and axial vectors and between scalars and pseudo scalars. Then a total of eight elements are often considered even if they are not given the correct name of multivectors. Eventually because of their simplicity, only the vectorial algebra or the quaternions algebra are explicitly used for physical applications. Nevertheless, it should be more convenient to use directly more complex algebras in order to have a wider range of application. The aim of this paper is to inquire into one particular Clifford algebra which could solve this problem. The present study is both didactic concerning its construction and pragmatic because of the introduced applications. The construction method is not an original one. But this latter allows to build up the associated real algebra as well as a peculiar formalism that enables a formal analogy with the classical vectorial algebra. Finally several fields of the theoretical physics will be described thanks to this algebra, as well as a more applied case in general relativity emphasizing simultaneously its relative validity in this particular domain and the easiness of modeling some physical problems.

  7. On n-ary algebras, branes and poly-vector gauge theories in noncommutative Clifford spaces

    International Nuclear Information System (INIS)

    In this paper, poly-vector-valued gauge field theories in noncommutative Clifford spaces are presented. They are based on noncommutative (but associative) star products that require the use of the Baker-Campbell-Hausdorff formula. Using these star products allows the construction of actions for noncommutative p-branes (branes moving in noncommutative spaces). Noncommutative Clifford-space gravity as a poly-vector-valued gauge theory of twisted diffeomorphisms in Clifford spaces would require quantum Hopf algebraic deformations of Clifford algebras. We proceed with the study of n-ary algebras and find an important relationship among the n-ary commutators of the noncommuting spacetime coordinates [X1, X2, ..., Xn] with the poly-vector-valued coordinates X123...n in noncommutative Clifford spaces given by [X1, X2, ..., Xn] = n!X123...n. The large N limit of n-ary commutators of n hyper-matrices Xi1i2...in leads to Eguchi-Schild p-brane actions for p + 1 = n. A noncomutative n-ary . product of n functions is constructed which is a generalization of the binary star product * of two functions and is associated with the deformation quantization of n-ary structures and deformations of the Nambu-Poisson brackets.

  8. On n-ary algebras, branes and poly-vector gauge theories in noncommutative Clifford spaces

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Carlos, E-mail: perelmanc@hotmail.co [Center for Theoretical Studies of Physical Systems, Clark Atlanta University, Atlanta, GA 30314 (United States)

    2010-09-10

    In this paper, poly-vector-valued gauge field theories in noncommutative Clifford spaces are presented. They are based on noncommutative (but associative) star products that require the use of the Baker-Campbell-Hausdorff formula. Using these star products allows the construction of actions for noncommutative p-branes (branes moving in noncommutative spaces). Noncommutative Clifford-space gravity as a poly-vector-valued gauge theory of twisted diffeomorphisms in Clifford spaces would require quantum Hopf algebraic deformations of Clifford algebras. We proceed with the study of n-ary algebras and find an important relationship among the n-ary commutators of the noncommuting spacetime coordinates [X{sup 1}, X{sup 2}, ..., X{sup n}] with the poly-vector-valued coordinates X{sup 123...n} in noncommutative Clifford spaces given by [X{sup 1}, X{sup 2}, ..., X{sup n}] = n!X{sup 123...n}. The large N limit of n-ary commutators of n hyper-matrices X{sub i{sub 1i{sub 2...i{sub n}}}} leads to Eguchi-Schild p-brane actions for p + 1 = n. A noncomutative n-ary . product of n functions is constructed which is a generalization of the binary star product * of two functions and is associated with the deformation quantization of n-ary structures and deformations of the Nambu-Poisson brackets.

  9. MD 751: Train Instability Threshold

    CERN Document Server

    Carver, Lee Robert; Metral, Elias; Salvant, Benoit; Levens, Tom; Nisbet, David; Zobov, M; CERN. Geneva. ATS Department

    2016-01-01

    The purpose of this MD is to measure the octupole current thresholds for stability for a single bunch, and then make an immediate comparison (with the same operational settings) for a train of 72 bunches separated by 25ns. From theory, the expected thresholds should be similar. Any discrepancy between the two cases will be of great interest as it could indicate the presence of additional mechanisms that contribute to the instability threshold, for example electron cloud.

  10. On supergroups with odd Clifford parameters and non-anticommutative supersymmetry

    International Nuclear Information System (INIS)

    We investigate super groups with Grassmann parameters replaced by odd Clifford parameters. The connection with non-anti commutative supersymmetry is discussed. A Berezin-like calculus for odd Clifford variables is introduced. Fermionic covariant derivatives for super groups with odd Clifford variables are derived. Applications to supersymmetric quantum mechanics are made. Deformations of the original supersymmetric theories are encountered when the fermionic covariant derivatives do not obey the graded Leibniz property. The simplest non-trivial example is given by the N = 2 SQM with a real (1, 2, 1) multiplet and a cubic potential. The action is real. Depending on the overall sign ('Euclidean' or 'Lorentzian') of the deformation, a Bender-Boettcher pseudo-hermitian Hamiltonian is encountered when solving the equation of motion of the auxiliary field. A possible connection of our framework with the Drinfeld twist deformation of supersymmetry is pointed out. (author)

  11. A symplectic subgroup of a pseudounitary group as a subset of Clifford algebra

    OpenAIRE

    Marchuk, Nikolai; Dyabirov, Roman

    2008-01-01

    Let Cl1(1,3) and Cl2(1,3) be the subsets of elements of the Clifford algebra Cl(1,3) of ranks 1 and 2 respectively. Recently it was proved that the subset Cl2(p,q)+iCl1(p,q) of the complex Clifford algebra can be considered as a Lie algebra. In this paper we prove that for p=1, q=3 the Lie algebra Cl2(p,q)+iCl1(p,q) is isomorphic to the well known matrix Lie algebra sp(4,R) of the symplectic Lie group Sp(4,R). Also we define the so called symplectic group of Clifford algebra and prove that th...

  12. Deformed Clifford algebra and supersymmetric quantum mechanics on a phase space with applications in quantum optics

    International Nuclear Information System (INIS)

    In order to realize supersymmetric quantum mechanics methods on a four-dimensional classical phase space, the complexified Clifford algebra of this space is extended by deforming it with the Moyal star product in composing the components of Clifford forms. Two isospectral matrix Hamiltonians having a common bosonic part but different fermionic parts depending on four real-valued phase-space functions are obtained. The Hamiltonians are doubly intertwined via matrix-valued functions which are divisors of zero in the resulting Moyal-Clifford algebra. Two illustrative examples corresponding to Jaynes-Cummings-type models of quantum optics are presented as special cases of the method. Their spectra, eigenspinors and Wigner functions as well as their constants of motion are also obtained within the autonomous framework of deformation quantization.

  13. Real Clifford Algebra Cl(n,0), n=2,3(mod 4) Wavelet Transform

    OpenAIRE

    Hitzer, Eckhard

    2013-01-01

    We show how for $n=2,3 (\\mod 4)$ continuous Clifford (geometric) algebra (GA) $Cl_n$-valued admissible wavelets can be constructed using the similitude group $SIM(n)$. We strictly aim for real geometric interpretation, and replace the imaginary unit $i \\in \\C$ therefore with a GA blade squaring to $-1$. Consequences due to non-commutativity arise. We express the admissibility condition in terms of a $Cl_{n}$ Clifford Fourier Transform and then derive a set of important properties such as dila...

  14. Clifford algebra and the structure of point groups in higher-dimensional spaces

    International Nuclear Information System (INIS)

    With the basic Clifford units being identified as mirrors, it is demonstrated how proper and improper symmetry operations of point groups in spaces of arbitrary dimensions can be parametrized. In such an approach consistency with parametrizations for groups in three dimensions can be achieved even if double groups are considered. The conversion of Clifford parameters into Cartesian matrices and vice versa is discussed and, for rotations in R4, also the parametrization in terms of pairs of rotations in R3. The formalism is illustrated by a number of examples

  15. The Inharmonious Conflicts in Robert Frost's Poetry

    Institute of Scientific and Technical Information of China (English)

    杨苗

    2015-01-01

    Robert Frost is one of the most distinguished poets,most of his poems are about the inharmonious relationship between nature and men,Conflicts are like a“thread”appearing in his poems.Frost’s true philosophy on men and life contributes to his wisdom and artistic poems.Frost tries to illustrate the conflict between nature and men in philosophy concern.

  16. Robert Aymar, Director-General of CERN

    CERN Multimedia

    Patrice Loïez

    2003-01-01

    Robert Aymar, photographed in 2003 before taking his position as Director-General at CERN, succeeding Luciano Maiani in 2004. At this time, Aymar was director of the International Thermonuclear Experimental Reactor (ITER) although he had already been involved with developments at CERN, chairing the External Review Committee, set up in 2001 in response to the increased cost of the LHC.

  17. Robert Lee Pyle honored with emeritus status

    OpenAIRE

    Douglas, Jeffrey S.

    2007-01-01

    Dr. Robert Lee Pyle of Blacksburg, professor of cardiology in the Department of Small Animal Clinical Science at the Virginia-Maryland Regional College of Veterinary Medicine at Virginia Tech, was conferred the "professor emeritus" title by the Virginia Tech Board of Visitors during the board's quarterly meeting August 27.

  18. Robert Aumann

    DEFF Research Database (Denmark)

    Hansen, Pelle Guldborg

    2007-01-01

    In this interview Nobel Prize Winner Robert Aumann talks about how he was initially drawn into game theory, when he came to think of formalizing the folk-theorem, the proper role of game theory in relation to other disciplines and why behavioral game theory probably won't last long....

  19. Beyond War Stories: Clifford G. Christians' Influence on the Teaching of Media Ethics, 1976-1984.

    Science.gov (United States)

    Peck, Lee Anne

    Clifford Glenn Christians' work in the area of media ethics education from 1976 through 1984 has influenced the way media ethics is taught to many college students today. This time period includes, among his other accomplishments, Christians' work on an extensive survey of how media ethics was taught in the late 1970s, his work on the Hastings…

  20. A Clifford Algebra approach to the Discretizable Molecular Distance Geometry Problem

    OpenAIRE

    Andrioni, Alessandro

    2013-01-01

    The Discretizable Molecular Distance Geometry Problem (DMDGP) consists in a subclass of the Molecular Distance Geometry Problem for which an embedding in ${\\mathbb{R}^3}$ can be found using a Branch & Prune (BP) algorithm in a discrete search space. We propose a Clifford Algebra model of the DMDGP with an accompanying version of the BP algorithm.

  1. Advancing Scholarship and Intellectual Productivity: An Interview with Clifford A. Lynch

    Science.gov (United States)

    Hawkins, Brian L.

    2006-01-01

    In this second part of a two-part interview with Clifford A. Lynch, Executive Director of the Coalition for Networked Information, Lynch talks to Hawkins about the most provocative and exciting projects that are being developed in the field of networked information worldwide. He also talks on how institutional repositories are being currently…

  2. The Actions Of Subgroups Of $SL$ For The Clifford Algebra In EPH Cases

    OpenAIRE

    Biswas, Debapriya

    2011-01-01

    We study the action of each subgroup $A$, $N$ and $K$ of the group $SL_2(\\mathbb{R})$ for the Clifford algebra $\\mathcal{C}\\ell(a)$ and calculate their vector fields, using the derived representation of the Lie algebra $sl_{2}$.

  3. Analytic Properties of the Conformal Dirac Operator on the Sphere in Clifford Analysis

    OpenAIRE

    Pansano, Brett

    2015-01-01

    In this paper the conformal Dirac operator on the sphere is defined to be operating on the space of square-integrable Clifford algebra-valued functions. The spinorial Laplacian of order d>0 is defined and used to establish Sobolev embedding theorems.

  4. Fierz identities for real Clifford algebras and the number of supercharges

    International Nuclear Information System (INIS)

    One considers supersymmetric gauge theories in quantum mechanics with the bosons and fermions belonging to the adjoint representation of the gauge group. One shows that the supersymmetry constraints are related to the existence of certain Fierz identities for real Clifford algebras. These identities are valid when one has 2, 4, 8, and 16 supercharges

  5. The peak algebra and the Hecke-Clifford algebras at $q=0$

    OpenAIRE

    Bergeron, Nantel; Hivert, Florent; Thibon, Jean-Yves

    2003-01-01

    Using the formalism of noncommutative symmetric functions, we derive the basic theory of the peak algebra of symmetric groups and of its graded Hopf dual. Our main result is to provide a representation theoretical interpretation of the peak algebra and its graded dual as Grothendieck rings of the tower of Hecke-Clifford algebras at $q=0$.

  6. Q-analogues of Clifford and Weyl algebras - spinor and oscillator representations of quantum enveloping algebra

    International Nuclear Information System (INIS)

    We introduce q-analogues of Clifford and Weyl algebras. Using these, we construct spinor and oscillator representations of quantum enveloping algebras of type AN-1, BN, CN, DN and AN-1(1). Also we discuss the irreducibility and the unitarity of these representations. (orig.)

  7. Causal phase-space approach to fermion theories understood through Clifford algebras

    International Nuclear Information System (INIS)

    A Wigner-Moyal phase-space approach is developed for the Dirac and Feynman-Gell-Mann equations. The role of spinors as primitive elements of the spacetime and phase-space Clifford algebras is emphasized. A conserved phase-space current is constructed. (orig.)

  8. CONSTITUTIONAL TRADITIONALISM IN THE ROBERTS COURT

    Directory of Open Access Journals (Sweden)

    Louis J Virelli III

    2011-05-01

    Full Text Available The debate over the role of traditionalism in constitutional interpretation has itself become a tradition. It remains a popular and controversial topic among constitutional scholars and presents normative questions that are as divisive, difficult, and important today as at the Founding. Missing from the discussion, however, is a comprehensive account of how the Supreme Court has employed traditionalism-an approach that looks for meaning in present manifestations of longstanding practices or beliefs-in its constitutional jurisprudence. This project is the first to fill this gap by providing an exhaustive and systematic analysis of the Court's use of constitutional traditionalism. This article focuses on the Roberts Court's first five terms to provide an empirical foundation that will not only offer previously unavailable insights into the Court's current traditionalist practices, but will also set forth a useful framework for the ongoing normative debate over traditionalism. This project uses content analysis of key terms to identify every instance in which the Roberts Court employed traditionalism to interpret the Constitution. More specifically, this project set out to answer the following three questions: First, how frequently does the Roberts Court employ traditionalism in its constitutional jurisprudence? Second, how robust is the Court's use of traditionalism (i.e., is it used to interpret a broad or narrow range of constitutional provisions? And finally, how often and in what contexts do individual Justices on the Roberts Court rely on traditionalism in their own constitutional opinions? The research provided here suggests answers to all three of these questions. First, the data indicate that traditionalism has been relied upon regularly by the Roberts Court, appearing in nearly half of the Court's constitutional cases. Second, traditionalism is frequently applied to a wide variety of constitutional provisions: Two-thirds of the

  9. Cavity Voltage Phase Modulation MD

    CERN Document Server

    Mastoridis, T; Butterworth, A; Molendijk, J; Tuckmantel, J

    2012-01-01

    The LHC RF/LLRF system is currently setup for extremely stable RF voltage to minimize transient beam loading eects. The present scheme cannot be extended beyond nominal beam current since the demanded power would push the klystrons to saturation. For beam currents above nominal (and possibly earlier), the cavity phase modulation by the beam will be not be corrected (transient beam loading), but the strong RF feedback and One-Turn Delay feedback will still be active for loop and beam stability in physics. To achieve this, the voltage set point will be adapted for each bunch. The goal of this MD was to test an iterative algorithm that would adjust the voltage set point to achieve the optimal phase modulation for klystron forward power considerations.

  10. Robert Bellah, religion og menneskelig evolution

    DEFF Research Database (Denmark)

    Jensen, Hans Jørgen Lundager

    2013-01-01

    in the middle of 1st mill. BC, where new radical and intellectual ideas and practices, sceptial or world renouncing, appeared in China, India and Greece. Hopefully, Bellah's book will be a standard reference work in the academic study of religion and an inspiration for the history of religion in the future......ENGLISH ABSTRACT: Introduction to and discussion of Robert Bellah's major book, Religion in Human Evolution (2011). which defines and describes tribal religion (religion in pre-state societies), archaic religion (religion in early states) and religious currents in the axial age, the period...... to engage in historical and comparative studies. DANSK RESUMÉ: Introduktion til og diskussion af Robert Bellahs hovedværk fra 2011, Religion in Human Evolution, der definerer og beskriver tribal religion, dvs. religion i før-statslige samfund, arkaisk religion, dvs. religion i tidlig-statslige kulturer samt...

  11. Aitab hädaldamisest / Robert Antropov

    Index Scriptorium Estoniae

    Antropov, Robert, 1965-

    2006-01-01

    Endine politseijuht on seisukohal, et politseinike ja päästjate nappuses ei saa süüdistada ainult väikseid palku, küsimus on valikutes: kuidas ja millesse ressursse paigutada. Kalle Laanet ja Raivo Aeg vastavad küsimusele, mis on nende haldusalas konkreetselt kavas, et politsei saaks täita oma tegevusprioriteeti 100% ja tagada sisejulgeoleku. Vt. ka Robert Antropovi kommentaari 7. aug. Eesti Päevaleht lk. 2

  12. Robert Edwards: the path to IVF ☆

    OpenAIRE

    Johnson, Martin H

    2011-01-01

    The early influences on Robert Edwards’ approach to the scientific research that led to human IVF are described. His interest as a graduate student in the genetics of early mammalian development stimulated him later to investigate whether the origins of human genetic diseases such as Down, Klinefelter and Turner syndromes might be explained by events during egg maturation. This clinical problem provided the most powerful stimulus to achieve both oocyte maturation and fertilization in vitro in...

  13. Evaluating Robert Franks Economic Naturalist Writing Assignment

    OpenAIRE

    Wayne Geerling

    2011-01-01

    This paper begins by asking a fundamental question: why do students who take Economics at an introductory level often leave the subject without understanding even the most basic economic principles? The superficial answer seems to be that courses try to cover too many concepts at the expense of mastering the important threshold concepts. Another issue is the way Economics is taught and assessed. I will evaluate an alternative pedagogical device pioneered by Robert Frank: The Economic Naturali...

  14. Architecture of (impossibilities: Robert Smithson's expositive spaces

    Directory of Open Access Journals (Sweden)

    Bráulio Romeiro

    2012-06-01

    Full Text Available This work investigates the North American artist Robert Smithson’s considerations on traditional expositive spaces: the museum and art gallery, as well as unusual and unexplored spaces by art up to that time. Looking through his texts we notice some enhanced perspectives and reset others, increasing limitation set on White Cube’s abstract and neutral quality and the substantiation on ideologies behind of these spaces manifestation.

  15. On a Higher Order Cauchy-Pompeiu Formula for Functions with Values in a Universal Clifford Algebra

    OpenAIRE

    Zhongxiang, Zhang

    2007-01-01

    By constructing suitable kernel functions, a higher order Cauchy-Pompeiu formula for functions with values in a universal Clifford algebra is obtained, leading to a higher order Cauchy integral formula.

  16. A trial to find an elliptic quantum algebra for $sl_2$ using the Heisenberg and Clifford algebra

    OpenAIRE

    Shiraishi, Jun'ichi

    1994-01-01

    A Heisenberg-Clifford realization of a deformed $U(sl_{2})$ by two parameters $p$ and $q$ is discussed. The commutation relations for this deformed algebra have interesting connection with the theta functions.

  17. Harvesting graphics power for MD simulations

    NARCIS (Netherlands)

    J.A. van Meel; A. Arnold; D. Frenkel; S.F. Portegies Zwart; R.G. Belleman

    2008-01-01

    We discuss an implementation of molecular dynamics (MD) simulations on a graphic processing unit (GPU) in the NVIDIA CUDA language. We tested our code on a modern GPU, the NVIDIA GeForce 8800 GTX. Results for two MD algorithms suitable for short-ranged and long-ranged interactions, and a congruentia

  18. Fast Collision Attack on MD5

    NARCIS (Netherlands)

    Stevens, M.M.J.

    2006-01-01

    In this paper, we present an improved attack algorithm to find two-block collisions of the hash function MD5. The attack uses the same differential path of MD5 and the set of sufficient conditions that was presented by Wang et al. We present a new technique which allows us to deterministically fulfi

  19. Advances in Delta-md measurements

    OpenAIRE

    Ronga, Frederic Jean

    2003-01-01

    We report the current status of Delta-md measurements at B-factories. The most recent world average is Delta-md = 0.502+-0.007 1/ps (1.4% accuracy). An estimate of the errors for 500 1/fb data is also given.

  20. A Sharp Look at Robert E

    Science.gov (United States)

    2004-01-01

    This sharp, high-resolution image shows a rock target dubbed 'Robert E,' on a rock called Stone Mountain at Meridiani Planum, Mars. It is one of the highest-resolution images ever taken while looking at a rock on another planet. Scientists are studying this area, which measures 3 centimeters (1.2 inches) across, for clues about how the rock formed. The image was created by merging five separate images taken at varying distances from the target by the microscopic imager, an instrument located on the Mars Exploration Rover Opportunity's instrument deployment device, or 'arm.'

  1. ROBERT autonomous navigation robot with artificial vision

    International Nuclear Information System (INIS)

    This work, a joint research between ENEA (the Italian National Agency for Energy, New Technologies and the Environment) and DIGlTAL, presents the layout of the ROBERT project, ROBot with Environmental Recognizing Tools, under development in ENEA laboratories. This project aims at the development of an autonomous mobile vehicle able to navigate in a known indoor environment through the use of artificial vision. The general architecture of the robot is shown together with the data and control flow among the various subsystems. Also the inner structure of the latter complete with the functionalities are given in detail

  2. A Conversation with Robert C. Elston

    OpenAIRE

    Zheng, Gang; Li, Zhaohai; Geller, Nancy L

    2015-01-01

    Robert C. Elston was born on February 4, 1932, in London, England. He went to Cambridge University to study natural science from 1952–1956 and obtained B.A., M.A. and Diploma in Agriculture (Dip Ag). He came to the US at age 24 to study animal breeding at Cornell University and received his Ph.D. in 1959. From 1959–1960, he was a post-doctoral fellow in biostatistics at University of North Carolina (UNC), Chapel Hill, where he studied mathematical statistics. He then rose through the academic...

  3. Application of geometric algebra to electromagnetic scattering the Clifford-Cauchy-Dirac technique

    CERN Document Server

    Seagar, Andrew

    2016-01-01

    This work presents the Clifford-Cauchy-Dirac (CCD) technique for solving problems involving the scattering of electromagnetic radiation from materials of all kinds. It allows anyone who is interested to master techniques that lead to simpler and more efficient solutions to problems of electromagnetic scattering than are currently in use. The technique is formulated in terms of the Cauchy kernel, single integrals, Clifford algebra and a whole-field approach. This is in contrast to many conventional techniques that are formulated in terms of Green's functions, double integrals, vector calculus and the combined field integral equation (CFIE). Whereas these conventional techniques lead to an implementation using the method of moments (MoM), the CCD technique is implemented as alternating projections onto convex sets in a Banach space. The ultimate outcome is an integral formulation that lends itself to a more direct and efficient solution than conventionally is the case, and applies without exception to all types...

  4. Magnetic monopoles without string in the Kaehler-Clifford algebra: a geometrical interpretation

    International Nuclear Information System (INIS)

    In substitution for Dirac monopoles with string (and for topological monopoles) we have recently introduced monopoles without string on the basis of a generalized potential, the sum of a vector A and a pseudo-vector sub(γ5)B potential. By making recourse to the Clifford bundle C (τ M,g) [ T sub(x) M,g) = IR sup(1,3); C (T sub(x) M,g) = IR sub(1,3)], which just allows adding together for each x ε M tensors of different ranks, in a previous paper we succeeded in constructing a lagrangian and hamiltonian formalism for interacting monopoles and charges that can be regarded as satisfactory from various points of view. In the present note, after having completed our formalism, we put forth a purely geometrical interpretation of it within the Kaehler-Clifford bundle K (τ sup(*) M

  5. From Clifford Algebra of Nonrelativistic Phase Space to Quarks and Leptons of the Standard Model

    CERN Document Server

    Żenczykowski, Piotr

    2015-01-01

    We review a recently proposed Clifford-algebra approach to elementary particles. We start with: (1) a philosophical background that motivates a maximally symmetric treatment of position and momentum variables, and: (2) an analysis of the minimal conceptual assumptions needed in quark mass extraction procedures. With these points in mind, a variation on Born's reciprocity argument provides us with an unorthodox view on the problem of mass. The idea of space quantization suggests then the linearization of the nonrelativistic quadratic form ${\\bf p}^2 +{\\bf x}^2$ with position and momentum satisfying standard commutation relations. This leads to the 64-dimensional Clifford algebra ${Cl}_{6,0}$ of nonrelativistic phase space within which one identifies the internal quantum numbers of a single Standard Model generation of elementary particles (i.e. weak isospin, hypercharge, and color). The relevant quantum numbers are naturally linked to the symmetries of macroscopic phase space. It is shown that the obtained pha...

  6. The classical problem of the charge and pole motion. A satisfactory formalism by Clifford algebras

    International Nuclear Information System (INIS)

    In a previous paper of ours [Phys. Lett. B 173(1986) 233; B 188 (1987) 511E] we put forth a theoretical approach to magnetic monopoles without a string which is formulated in a Clifford bundle. To 'complete' our theory, we show that the Maxwell euqations - with magnetic monopoles - do imply the correct couplings of the electric current and magnetic current with the electromagnetic field (and, therefore, imply the Lorentz forces and the correct motion equations). In other words, within our Clifford approach to classical electromagnetism, the motion equations and the couplings are derivable from the field equations, without any further recourse to a variational principle and without any ad hoc postulate. The price to pay for that result seems merely to be a very natural assumption, analogous to a similar one that is quite standard in general relativity. (orig.)

  7. A multiexpert framework for character recognition: a novel application of Clifford networks.

    Science.gov (United States)

    Rahman, A R; Howells, W J; Fairhurst, M C

    2001-01-01

    A novel multiple-expert framework for recognition of handwritten characters is presented. The proposed framework is composed of multiple classifiers (experts) put together in such a manner as to enhance the recognition capability of the combined network compared to the best performing individual expert participating in the framework. Each of these experts has been derived from a novel neural structure in which the weight values are derived from Clifford algebra. A Clifford algebra is a mathematical paradigm capable of capturing the interdimensional dependencies found in multidimensional data. It offers a technique for concise data storage and processing by representing dependencies between the component dimensions of the data which is otherwise difficult to encode and hence is often employed in analyzing multidimensional data. Results achieved by the proposed multiple-expert framework demonstrates significant improvement over alternative techniques. PMID:18244366

  8. An explanation for galaxy rotation curves using a Clifford multivector spacetime framework

    CERN Document Server

    Chappell, James M; Iqbal, Azhar; Abbott, Derek

    2012-01-01

    We explore the consequences of space and time described within the Clifford multivector of three dimensions $ Cl_{3,0}$, where space consists of three-vectors and time is described with the three bivectors of this space. When describing the curvature around massive bodies, we show that this model of spacetime when including the Hubble expansion naturally produces the correct galaxy rotation curves without the need for dark matter.

  9. Frobenius character formula and spin generic degrees for Hecke-Clifford algebra

    OpenAIRE

    Wan, Jinkui; Wang, Weiqiang

    2012-01-01

    The spin analogues of several classical concepts and results for Hecke algebras are established. A Frobenius type formula is obtained for irreducible characters of the Hecke-Clifford algebra. A precise characterization of the trace functions allows us to define the character table for the algebra. The algebra is endowed with a canonical symmetrizing trace form, with respect to which the spin generic degrees are formulated and shown to coincide with the spin fake degrees. We further provide a ...

  10. Unified Bessel, Modified Bessel, Spherical Bessel and Bessel-Clifford Functions

    OpenAIRE

    Yaşar, Banu Yılmaz; Özarslan, Mehmet Ali

    2016-01-01

    In the present paper, unification of Bessel, modified Bessel, spherical Bessel and Bessel-Clifford functions via the generalized Pochhammer symbol [ Srivastava HM, Cetinkaya A, K{\\i}ymaz O. A certain generalized Pochhammer symbol and its applications to hypergeometric functions. Applied Mathematics and Computation, 2014, 226 : 484-491] is defined. Several potentially useful properties of the unified family such as generating function, integral representation, Laplace transform and Mellin tran...

  11. Robert Adrian X / Robert Adrian X ; interv. Tilman Baumgärtel

    Index Scriptorium Estoniae

    Adrian X, Robert

    2006-01-01

    1997. a. Ljubljanas tehtud intervjuu 1972. aastast Viinis elava kanada kunstniku Robert Adrian X-ga (sünd. 1935), kes töötas 1970-ndate lõpul ja 1980-ndate alguses telefoni, faksi ja varaste kirjakstisüsteemidega kunstiprojektide kallal, osales 1970-ndate ja 1980-ndate multimeediaprojektides

  12. Upper bounds on fault tolerance thresholds of noisy Clifford-based quantum computers

    International Nuclear Information System (INIS)

    We consider the possibility of adding noise to a quantum circuit to make it efficiently simulatable classically. In previous works, this approach has been used to derive upper bounds to fault tolerance thresholds-usually by identifying a privileged resource, such as an entangling gate or a non-Clifford operation, and then deriving the noise levels required to make it 'unprivileged'. In this work, we consider extensions of this approach where noise is added to Clifford gates too and then 'commuted' around until it concentrates on attacking the non-Clifford resource. While commuting noise around is not always straightforward, we find that easy instances can be identified in popular fault tolerance proposals, thereby enabling sharper upper bounds to be derived in these cases. For instance we find that if we take Knill's (2005 Nature 434 39) fault tolerance proposal together with the ability to prepare any possible state in the XY plane of the Bloch sphere, then not more than 3.69% error-per-gate noise is sufficient to make it classical, and 13.71% of Knill's γ noise model is sufficient. These bounds have been derived without noise being added to the decoding parts of the circuits. Introducing such noise in a toy example suggests that the present approach can be optimized further to yield tighter bounds.

  13. Clifford algebra unveils a surprising geometric significance of quaternionic root systems of Coxeter groups

    CERN Document Server

    Dechant, Pierre-Philippe

    2013-01-01

    Quaternionic representations of Coxeter (reflection) groups of ranks 3 and 4, as well as those of E_8, have been used extensively in the literature. The present paper analyses such Coxeter groups in the Clifford Geometric Algebra framework, which affords a simple way of performing reflections and rotations whilst exposing more clearly the underlying geometry. The Clifford approach shows that the quaternionic representations in fact have very simple geometric interpretations. The representations of the groups A_1 x A_1 x A_1, A_3, B_3 and H_3 of rank 3 in terms of pure quaternions are shown to be simply the Hodge dualised root vectors, which determine the reflection planes of the Coxeter groups. Two successive reflections result in a rotation, described by the geometric product of the two reflection vectors, giving a Clifford spinor. The spinors for the rank-3 groups A_1 x A_1 x A_1, A_3, B_3 and H_3 yield a new simple construction of binary polyhedral groups. These in turn generate the groups A_1 x A_1 x A_1 ...

  14. The many faces of Maxwell, Dirac and Einstein equations. A Clifford bundle approach

    International Nuclear Information System (INIS)

    This book is a thoughtful exposition of the algebra and calculus of differential forms, the Clifford and Spin-Clifford bundles formalisms with emphasis in calculation procedures, and vistas to a formulation of some important concepts of differential geometry necessary for a deep understanding of spacetime physics. The formalism discloses the hidden geometrical nature of spinor fields. Maxwell, Dirac and Einstein fields, which were originally considered objects of a very different mathematical nature, are shown to have representatives as objects of the same mathematical nature, i.e. as sections of an appropriate Clifford bundle. This approach reveals unity in the diversity and also the many faces of the equations satisfied by those fields. Moreover, it suggests relationships which are hidden in the standard formalisms and new paths for research. Some foundational issues of relativistic field theories, in particular the one concerning the conditions for the existence of the conservation laws of energy-momentum and angular momentum in spacetime theories and many misconceptions concerning this issue is analyzed in details. The book will be useful as reference book for researchers and advanced students of theoretical physics and mathematics. Calculation procedures are illustrated by many exercises solved in detail, using the ''tricks of the trade''. Furthermore the readers will appreciate the comprehensive list of mathematical symbols as well as a list of acronyms and abbreviations. (orig.)

  15. Clifford Algebras in relativistic quantum mechanics and in the gauge theory of electromagnetism

    International Nuclear Information System (INIS)

    A Clifford Algebra is an algebra associated with a finite-dimensional vector space and a symmetric form on that space. It contains a multiplicative subgroup, the group of spinors, which is related to the group of orthogonal transformations of the vector space. This group may act on the algebra via multiplication on the left or right, or by the adjoint action. First, the author considers the problem of classifying the orbits of these actions in the algebras C(3,1) and C(3,2). For a ceratin subclass of orbit this problem is completely solved and the isotropy groups for elements in these orbits are determined. After writing the Dirac and Maxwell equations in terms of Clifford Albebras, the author shows how a classification of the solutions to these equations is related to the orbit and isotropy group calculations. Finally, he shows how Clifford algebras may be used to define spinor and r-vector fields on manifolds, gradients of such fields, and other more familiar concepts from differential geometry. The end result is that the calculations for C(3,1) and C(3,2) may be applied to fields on space-time and on the five-dimensional space of the gauge theory of electromagnetism, respectively. This gauge theory also allows us to relate Einstein's equations for free space to Maxwell's equations in a natural manner

  16. Clifford Valued Differential Forms, and Some Issues in Gravitation, Electromagnetism and "unified" Theories

    Science.gov (United States)

    Rodrigues, W. A.; Capelas de Oliveira, E.

    In this paper we show how to describe the general theory of a linear metric compatible connection with the theory of Clifford valued differential forms. This is done by realizing that for each spacetime point the Lie algebra of Clifford bivectors is isomorphic to the Lie algebra of Sl(2,{ C}). In that way the pullback of the linear connection under a local trivialization of the bundle (i.e., a choice of gauge) is represented by a Clifford valued 1-form. That observation makes it possible to realize immediately that Einstein's gravitational theory can be formulated in a way which is similar to a Sl(2,{ C}) gauge theory. Such a theory is compared with other interesting mathematical formulations of Einstein's theory, and particularly with a supposedly "unified" field theory of gravitation and electromagnetism proposed by M. Sachs. We show that his identification of Maxwell equations within his formalism is not a valid one. Also, taking profit of the mathematical methods introduced in the paper we investigate a very polemical issue in Einstein gravitational theory, namely the problem of the 'energy-momentum' conservation. We show that many statements appearing in the literature are confusing or even wrong.

  17. Robert W. Rieber (1932-2015).

    Science.gov (United States)

    Weizmann, Fredric

    2016-01-01

    Presents the obituary of Robert W. Rieber (1932-2015). Robert W. Rieber, the son of immigrants from the former Austro- Hungarian Empire was born March 24, 1932. He earned a bachelor's degree at Pennsylvania State University and a master's degree in speech pathology at Temple University. He moved to New York City, New York, in 1957, working as a speech pathologist at New York University. In 1960, he accepted an academic position at Pace University, subsequently moving to the John Jay College of Criminal Justice at City University of New York. He held appointments at Columbia University and, following his retirement from John Jay, at Fordham University. Bob founded and edited several journals, including The Journal of Communication Disorders, The Journal of Social Distress and the Homeless, and The Journal of Psycholinguistics Research. While on leave from Pace, he completed his doctorate at the University of London with a dissertation on the relationship between language and psychopathology. Rieber died at his summer home in Maine on April 9, 2015. He was 83. PMID:26866991

  18. Multi-Dimensional Games (MD-Games)

    OpenAIRE

    Ruiz Estrada, M.A.

    2009-01-01

    This paper introduces the concept of Multi-Dimensional games (MD-games) based on the application of an alternative mathematical and graphical modeling approach to study the game theory from a multi-dimensional perspective. In fact, the MD-Games request the application of the mega-space coordinate system to visualize a large number of games, players, strategies and pay-offs functions into the same graphical space.

  19. Tributes to Professor Robert Berkley Harper

    Directory of Open Access Journals (Sweden)

    Carl G. Cooper

    2004-04-01

    Full Text Available In 1977, I began teaching at The University of Pittsburgh Law School and in short order one of my closest friends during my tenure there was Professor Robert “Bob” Harper. I wondered when I was hired whether I was selected because I looked strikingly similar to Bob, and perhaps the faculty thought my favoring Professor Harper would make my assimilation into the law school faculty that much easier. Students constantly called me Professor Harper and, indeed, many on the faculty called me Bob for several years; I never bothered to correct them. I thought if they paid that little attention to detail in law school, I would just let them go through life missing some of the finer points their education, and life for that matter, has to offer.

  20. Robert M. Wingfield, dc: A conscientious chiropractor.

    Science.gov (United States)

    Brown, Douglas M

    2015-09-01

    "I slept and dreamed that life was beauty. I woke - and found that life was duty." This quote from the poet Ellen Sturgis Hooper, could be attributed to Robert Wingfield, who has persevered in his quest for personal and professional excellence. This historical biography begins with his genealogy, going back to the 11(th) century in Merry England and ends in 2015, with his relatively quiet existence still centred in Ontario. The essay scrutinizes Dr. Wingfield's accomplishments for the Ontario Chiropractic Association (OCA), Canadian Chiropractic Association (CCA) and Ontario Board of Directors of Chiropractic (BDC). Moreover, it attempts to give the reader a glimpse into his personal endeavours, to help us fathom how he tackles (as William Shakespeare would say) "the thousand natural shocks that flesh is heir to." PMID:26500366

  1. Roger Chartier entretien avec Robert Darnton

    OpenAIRE

    Roger Chartier; por Robert Darnton

    2012-01-01

    Le dialogue présenté ici, entre Roger Chartier et Robert Darnton, eut lieu au Collège de France à l’occasion de la leçon inaugurale d’une nouvelle chaire nommée Écrits et culture dans l’Europe moderne, ayant Roger Chartier comme professeur titulaire. Le 11 octobre 2007, lors de l’ouverture de cette chaire, Chartier prononçait l’exposé “Écouter les morts avec les yeux”. Le vers du poète espagnol Quevedo (1580-1645), utilisé comme titre de la leçon, était cité par Chartier pour évoquer les abse...

  2. The strange trial of Robert Oppenheimer

    International Nuclear Information System (INIS)

    Robert Oppenheimer has become the symbol of the scientist tormented and anguished by the consequences of his discoveries. R.Oppenheimer took a major part in the Manhattan project for the designing of the first atomic bomb. During this period he considered the thermonuclear bomb as the next step to reach but after Japan's surrender he reconsidered his position and favoured a more moderate atomic policy. R.Oppenheimer began to militate in favour of an international control of nuclear energy and wanted that Usa relinquish to design the hydrogen bomb. In 1953 in full Mac-Carthysm era, he was accused of being a communist and of spying for Ussr and as a consequence he was deprived of his office in AEC (atomic energy committee) but in 1963 president Lyndon Johnson rehabilitated him and R.Oppenheimer was awarded the highest reward of AEC: the Enrico Fermi prize. (A.C.)

  3. Robert Williams Wood: pioneer of invisible light.

    Science.gov (United States)

    Sharma, Shruti; Sharma, Amit

    2016-03-01

    The Wood's lamp aids in the diagnosis of multiple infectious, inflammatory and neoplastic dermatologic conditions. Although the Wood's lamp has many applications, which have improved both the diagnosis and management of disease, the man credited for its invention is relatively unknown in medicine. Robert Williams Wood, a prominent physicist of the early 20th century, is credited for the invention of the Wood's lamp. Wood was the father of infrared and ultraviolet photography and made significant contributions to other areas in optics and spectroscopy. Wood's work encompassed the formative years of American Physics; he published over 200 original papers over his lifetime. A few years after the invention of the Wood's lamp for ultraviolet photography, physicians in Europe adopted the Wood's lamp for dermatologic applications. Wood's lamp remains popular in clinics globally, given its ease of use and ability to improve diagnostic precision. PMID:26752503

  4. Robert Aymar leaves ITER for CERN

    International Nuclear Information System (INIS)

    As of 1 September 2003, Dr. Robert Aymar, former ITER Director and subsequently Interim Project Leader, has relinquished his leadership of the ITER Project. I am convinced that everyone involved in the ITER activities will join me in expressing our sincere appreciation of Dr. Aymar's enormous contribution to the success of the ITER Project during the EDA and ITA phases. Dr. Aymar was appointed Director of ITER by the ITER Council in July 1994, after having served for nearly two years as a member of the ITER Technical Advisory Committee. Under his leadership, the results of 50 years of fusion research crystallized into the engineering project ready for practical implementation. The successful results of the ITER activities helped to attract the new ITER Participants who joined in 2003, and the countries participating in ITER now represent almost half of the world population

  5. Assume the Positional: Comment on Robert Frank

    Directory of Open Access Journals (Sweden)

    ANDREW KASHDAN

    2006-09-01

    Full Text Available We examine Robert Frank’s arguments for taxation to mitigate positional externalities. The scarcity that characterizes positional goods is real, but various mechanisms reduce the potential waste, and Frank overstates the case for a governmental solution. The plausibility of Frank’s arguments for extensive market failure requires various assumptions, including the usefulness of happiness comparisons over time, the widespread existence of winner-take-all markets, the failure of voluntary evolution to internalize externalities, and that both “leisure” and governmental activities are significantly less positional than the full-range of activities Frank proposes to tax. Each assumption is shaky. Frank’s policy solutions overlook standard public choice arguments against government expansion and shrug off the Smithian burden of proof incumbent on those proposing coercion.

  6. Robert Edwards: the path to IVF☆

    Science.gov (United States)

    Johnson, Martin H

    2011-01-01

    The early influences on Robert Edwards’ approach to the scientific research that led to human IVF are described. His interest as a graduate student in the genetics of early mammalian development stimulated him later to investigate whether the origins of human genetic diseases such as Down, Klinefelter and Turner syndromes might be explained by events during egg maturation. This clinical problem provided the most powerful stimulus to achieve both oocyte maturation and fertilization in vitro in humans. Indeed, preimplantation genetic diagnosis was his main goal until he met Patrick Steptoe in 1968. A re-evaluation of his meeting with Steptoe suggests that initially Steptoe’s laparoscopic skill was of interest for its potential to solve the sperm capacitation problem. Steptoe’s impact on Edwards was twofold. First, Steptoe’s long-held interest in infertility raised this application of IVF higher in Edwards’ priorities. Second, Steptoe offered a long-term partnership, in which oocyte collection without in-vitro maturation was a possibility. The professional criticism generated by their work together encouraged Edwards to pursue a deliberate programme of public education about the issues raised and to challenge and develop professional bioethical thought and discourse about reproduction. The early life and career of Robert Edwards are described and re-evaluated in the light of documentary evidence. His early interest in the genetics of development provided the major motivation behind his goal of achieving IVF in humans. Through this work, he aimed to understand and hopefully to reduce the transmission of genetic disease in humans. His meeting with Patrick Steptoe, the details of which are re-examined, increased the significance for Edwards of infertility as an outcome of IVF. It also led to a creative long-term research partnership, initiated a long-term programme of public education in the UK about reproductive science and stimulated the development of

  7. Anthony ROBERTS 5 March 1948 – 16 January 2008

    CERN Multimedia

    TS Department

    2008-01-01

    We deeply regret to announce the death of Mr Anthony ROBERTS on 16 January 2008. Mr ROBERTS, born on 05.03.1948, worked in the HR Department and had been employed at CERN since 01.06.1973. The Director-General has sent his family a message of condolence on behalf of the CERN staff. Social Affairs Service Human Resources Department

  8. MD5算法的分析和改进%Analysis and Improvement of .MD5 Algorithm

    Institute of Scientific and Technical Information of China (English)

    么丽颖

    2011-01-01

    首先研究了MD5算法,并总结了MD5算法的特点及性能,在研究MD5算法的基础之上,提出了MD5改进加密算法.最后,对MD5算法与MD5改进算法对应于相关数据、性能进行了比较.%At first , MD5 algorithm is researched, and the characteristic and capability of the MD5 are summaried in the paper. The improved MD5 algorithm is put forward based on the research of the MDS. At last, the contrast between MD5 algorithm and the improved MD5 algorithm in related datum and capability are put forward.

  9. Fast Collision Attack on MD5

    OpenAIRE

    Stevens, Marc

    2006-01-01

    In this paper, we present an improved attack algorithm to find two-block collisions of the hash function MD5. The attack uses the same differential path of MD5 and the set of sufficient conditions that was presented by Wang et al. We present a new technique which allows us to deterministically fulfill restrictions to properly rotate the differentials in the first round. We will present a new algorithm to find the first block and we will use an algorithm of Klima to find the second block. To o...

  10. Harvesting graphics power for MD simulations

    OpenAIRE

    Meel, van, C.S.; Arnold, A; Frenkel, D.; Portegies Zwart, S.F.; Belleman, R.G.

    2008-01-01

    We discuss an implementation of molecular dynamics (MD) simulations on a graphic processing unit (GPU) in the NVIDIA CUDA language. We tested our code on a modern GPU, the NVIDIA GeForce 8800 GTX. Results for two MD algorithms suitable for short-ranged and long-ranged interactions, and a congruential shift random number generator are presented. The performance of the GPU’s is compared to their main processor counterpart. We achieve speedups of up to 40, 80 and 150 fold, respectively. With the...

  11. Harvesting graphics power for MD simulations

    OpenAIRE

    2008-01-01

    Abstract We discuss an implementation of molecular dynamics (MD) simulations on a graphic processing unit (GPU) in the NVIDIA CUDA language. We tested our code on a modern GPU, the NVIDIA GeForce 8800 GTX. Results for two MD algorithms suitable for short-ranged and long-ranged interactions, and a congruential shift random number generator are presented. The performance of the GPU's is compared to their main processor counterpart. We achieve speedups of up to 80, 40 and 150 fold, re...

  12. Induced Semantics for Undirected Graphs: Another Look at the Hammersley-Clifford Theorem

    Science.gov (United States)

    Sears, Timothy D.; Sunehag, Peter

    2007-11-01

    The Hammersley-Clifford (H-C) theorem relates the factorization properties of a probability distribution to the clique structure of an undirected graph. If a density factorizes according to the clique structure of an undirected graph, the theorem guarantees that the distribution satisfies the Markov property and vice versa. We show how to generalize the H-C theorem to different notions of decomposability and the corresponding generalized-Markov property. Finally we discuss how our technique might be used to arrive at other generalizations of the H-C theorem, inducing a graph semantics adapted to the modeling problem.

  13. First order differential operator associated to the Cauchy-Riemann operator in a Clifford algebra

    International Nuclear Information System (INIS)

    The complex differentiation transforms holomorphic functions into holomorphic functions. Analogously, the conjugate Cauchy-Riemann operator of the Clifford algebra transforms regular functions into regular functions. This paper determines more general first order operator L (matrix-type) for which Lu is regular provided u is regular. For such operator L, the initial value problem ∂u / ∂t = L (t, x, u, ∂u / ∂x) (1) u(0, x) = φ(x) (2) is solvable for an arbitrary regular function φ and the solution is regular in x for each t. (author)

  14. Analytical error analysis of Clifford gates by the fault-path tracer method

    Science.gov (United States)

    Janardan, Smitha; Tomita, Yu; Gutiérrez, Mauricio; Brown, Kenneth R.

    2016-05-01

    We estimate the success probability of quantum protocols composed of Clifford operations in the presence of Pauli errors. Our method is derived from the fault-point formalism previously used to determine the success rate of low-distance error correction codes. Here we apply it to a wider range of quantum protocols and identify circuit structures that allow for efficient calculation of the exact success probability and even the final distribution of output states. As examples, we apply our method to the Bernstein-Vazirani algorithm and the Steane [[7,1,3

  15. Fermi-Bose duality of the Dirac equation and extended real Clifford-Dirac algebra

    Directory of Open Access Journals (Sweden)

    I.Yu. Krivsky

    2010-01-01

    Full Text Available We have proved on the basis of the symmetry analysis of the standard Dirac equation with nonzero mass that this equation may describe not only fermions of spin 1/2 but also bosons of spin 1. The new bosonic symmetries of the Dirac equation in both the Foldy-Wouthuysen and the Pauli-Dirac representations are found. Among these symmetries (together with the 32-dimensional pure matrix algebra of invariance the new, physically meaningful, spin 1 Poincare symmetry of equation under consideration is proved. In order to provide the corresponding proofs, a 64-dimensional extended real Clifford-Dirac algebra is put into consideration.

  16. Generalization of the twistor to Clifford algebras as a basis for geometry

    International Nuclear Information System (INIS)

    The Penrose twistor theory to a Clifford algebra is generated. This allows basic geometric forms and relationships to be expressed purely algebraically. In addition, by means of an inner automorphism of this algebra, it is possible to regard these forms and relationships as emerging from a deeper pre-space, which it is calling an implicate order. The way is then opened up for a new mode of description, that does not start from continuous space-time, but which allows this to emerge as a limiting case. (Author)

  17. Hecke-Clifford Algebras and Spin Hecke Algebras IV: Odd Double Affine Type

    Directory of Open Access Journals (Sweden)

    Ta Khongsap

    2009-01-01

    Full Text Available We introduce an odd double affine Hecke algebra (DaHa generated by a classical Weyl group $W$ and two skew-polynomial subalgebras of anticommuting generators. This algebra is shown to be Morita equivalent to another new DaHa which are generated by $W$ and two polynomial-Clifford subalgebras. There is yet a third algebra containing a spin Weyl group algebra which is Morita (superequivalent to the above two algebras. We establish the PBW properties and construct Verma-type representations via Dunkl operators for these algebras.

  18. Relativistic quantum theory of fermions based on the Clifford algebra C7

    International Nuclear Information System (INIS)

    A relativistic quantum theory of spin- 1/2 fermions is presented that includes a charge algebra, as well as an operator that distinguishes between leptons and baryons. This, in effect, extends the Clifford algebra C4 of Dirac's γ matrices to C7. Moreover, the particle states Psi are represented here by elements of C7 as products of projection operators, instead of column vectors. A number of important results are derived, and the theory serves as a foundation for constructing physical particle states as tensor products of the bare fermion states

  19. A Clifford-gravity-based cosmology, dark matter and dark energy

    Science.gov (United States)

    Castro, Carlos

    2015-02-01

    A Clifford-gravity-based model is exploited to build a generalized action (beyond the current ones used in the literature) and arrive at relevant numerical results which are consistent with the presently-observed de Sitter accelerating expansion of the universe driven by a very small vacuum energy density ρobs 10-120(MP)4 (MP is the Planck mass) and provide promising dark energy/matter candidates in terms of the 16 scalars corresponding to the degrees of freedom associated with a Cl(3, 1)-algebra-valued scalar field Φ in four dimensions.

  20. A new linear Dirac-like spin-3/2 wave equation using Clifford algebra

    International Nuclear Information System (INIS)

    A new linear Dirac-like wave equation for spin-3/2 is derived, employing four of the seven irreducible eight-dimensional matrices obeying the Clifford algebra C7 with the wave function having the needed eight components only. Though this wave equation is not manifestly covariant and the wave function employed is not locally covariant, it is relativistically invariant and by its very derivation is connected to the Weaver, Hammer and Good (Phys. Rev.; 135: B241 (1964)) formalism for spin-3/2 by a chain of transformations which can be arbitrarily chosen to be either unitary or non-unitary. (author)

  1. A sequence of Clifford algebras and three replicas of Dirac particle

    International Nuclear Information System (INIS)

    The embedding of Dirac algebra into a sequence N=1, 2, 3,... of Clifford algebras is discussed, leading to Dirac equations with N=1 additional, electromagnetically ''hidden'' spins 1/2. It is shown that there are three and only three replicas N=1, 3, 5 of Dirac particle if the theory of relativity together with the probability interpretation of wave function is applied both to the ''visible'' spin and ''hidden'' spins, and a new ''hidden exclusion principle''is imposed on the wave function (then ''hidden'' spins add up to zero). It is appealing to explore this idea in order to explain the puzzle of three generations of lepton and quarks. (author)

  2. ProtoMD: A Prototyping Toolkit for Multiscale Molecular Dynamics

    OpenAIRE

    Somogyi, Endre; Mansour, Andrew Abi; Ortoleva, Peter J.

    2013-01-01

    ProtoMD is a toolkit that facilitates the development of algorithms for multiscale molecular dynamics (MD) simulations. It is designed for multiscale methods which capture the dynamic transfer of information across multiple spatial scales, such as the atomic to the mesoscopic scale, via coevolving microscopic and coarse-grained (CG) variables. ProtoMD can be also be used to calibrate parameters needed in traditional CG-MD methods. The toolkit integrates `GROMACS wrapper' to initiate MD simula...

  3. Magnetohydrodynamics and the earth's core selected works by Paul Roberts

    CERN Document Server

    Soward, Andrew M

    2003-01-01

    Paul Roberts'' research contributions are remarkable in their diversity, depth and international appeal. Papers from the Paul Roberts'' Anniversary meeting at the University of Exeter are presented in this volume. Topics include geomagnetism and dynamos, fluid mechanics and MHD, superfluidity, mixed phase regions, mean field electrodynamics and the Earth''s inner core. An incisive commentary of the papers puts the work of Paul Roberts into historical context. Magnetohydrodynamics and the Earth''s Core provides a valuable source of reference for graduates and researchers working in this area of geoscience.

  4. Robert R. Bennett memorial to GIFT fund

    Science.gov (United States)

    The many personal friends, colleagues, and professional associates of the late Robert R. Bennett have joined in establishing a memorial in his honor. In recognition of his vigorous support of the American Geophysical Union, they have contributed in his memory to AGU's ‘Girding for Tomorrow’ program. His name will be inscribed on a list of honorees that will be displayed on a plaque in the AGU headquarters in Washington, D.C.Bennett, who received his M.S. in geology from the University of Nebraska in 1939, formerly directed groundwater research in the Water Resources Division of the U.S. Geological Survey. He was nationally and internationally recognized as an outstanding scientist in hydrogeology and groundwater hydrology. He was a pioneer authority in the development and application of analog- and digital-computer simulations that aid in the analysis and prediction of the responses of highly complex aquifer systems to stresses imposed by man's development and utilization. He conducted basic research in petrophysics to define the fundamental principles governing permeability distribution and its directional characteristics and to elucidate the manner in which the permeability factor controls the movement of water in aquifer systems. He tested the applicability of the concepts he developed with prototype studies of the Ten-sleep sandstone in the Big Horn Basin of Wyoming and of the Carrizo sandstone in the Coastal Plain of Texas.

  5. Robert Aymar awarded Global Energy prize

    CERN Multimedia

    2006-01-01

    CERN Director-General Robert Aymar was recently named one of three laureates of the 2006 Global Energy International Prize for 'the development of scientific and engineering foundation for the ITER project.' ITER is an experiment planned to be built in Europe at Cadarache (South of France) and designed to show the scientific and technological feasibility of a full-scale fusion power reactor. The other two laureates, who worked with Aymar on the project, are former President of the ITER Council, Russian Academician Evgeny Velikhov, and Japan's Dr Masaji Yoshikawa, ITER's former Vice President. Aymar headed ITER from 1994 to 2003. 'This prize is not only a great honour for me and my friends and colleagues of many years at ITER, Evgeny Velikhov and Masaji Yoshikawa,' Aymar said. 'It is above all a recognition of the effort of all those who have been involved with the ITER project and worked over the years to ensure the first step in proving that fusion will provide a new sustainable energy source for the plane...

  6. 78 FR 2707 - Maryland Disaster # MD-00026

    Science.gov (United States)

    2013-01-14

    ... From the Federal Register Online via the Government Publishing Office SMALL BUSINESS ADMINISTRATION Maryland Disaster MD-00026 AGENCY: U.S. Small Business Administration. ACTION: Notice. SUMMARY... INFORMATION CONTACT: A. Escobar, Office of Disaster Assistance, U.S. Small Business Administration, 409...

  7. TBT recommends : Vera Bila. The No Smoking Orchestra. Robert Plant

    Index Scriptorium Estoniae

    2005-01-01

    Mustlasansambli Kale ja Vera Bila kontserdist 8. apr Tallinnas. Bosnia filmirežissööri Emir Kusturica ja tema ansambli No Smoking Orchestra kontserdist 12. apr. Riias. Inglise rocklaulja Robert Planti kontserdist 10. apr. Vilniuses

  8. Post sdal, port prinjal / Robert Antropov ; interv. Oksana Avdejeva

    Index Scriptorium Estoniae

    Antropov, Robert, 1965-

    2006-01-01

    Endine politseiameti peadirektor Robert Antropov Tõnismäe pronkssõduri ümber toimuvast ning valitsuse otsustusvõimetusest, sammud, mida oleks vaja teha sisejulgeoleku tagamiseks, poliitikast, perekonnast

  9. Research Ship Robert Gordon Sproul Underway Meteorological Data, Quality Controlled

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Research Ship Robert Gordon Sproul Underway Meteorological Data (delayed ~10 days for quality control) are from the Shipboard Automated Meteorological and...

  10. 77 FR 40609 - Robert D. Willis Power Rate

    Science.gov (United States)

    2012-07-10

    ... entitled Power Marketing Administration Financial Reporting. Procedures for Public Participation in Power... Southwestern Power Administration Robert D. Willis Power Rate AGENCY: Southwestern Power Administration, DOE... Administration (Southwestern), has prepared Current and Revised 2012 Power Repayment Studies which show the...

  11. Robert Rodrigueze verejugadega õudusfilm tuleb Igavuse planeedilt / Mihkel Raud

    Index Scriptorium Estoniae

    Raud, Mihkel, 1969-

    2007-01-01

    Filmiprojekt "Grindhouse" koosneb Robert Rodrigueze retroõudukast "Grindhouse : Õuduste planeet" ("Planet Terror") ja Quentin Tarantino 70-ndatest inspireeritud õudusfilmist "Surmakindel" ("Death Proof") : Ameerika Ühendriigid 2007. R. Rodrigueze filmist

  12. Astronaut Robert Gibson prepares to use motion picture camera

    Science.gov (United States)

    1986-01-01

    Astronaut Robert L. Gibson, STS 61-C mission commander, partially floats on the aft flight deck of the Shuttle Columbia while preparing to use a motion picture camera. The windows overlooking the cargo bay are visible in the background.

  13. Obituary: Robert H. Koch (1929-2010)

    Science.gov (United States)

    Koch, Joanne; Corcoran, Michael; Holenstein, Bruce; Sion, Edward

    2011-12-01

    Robert H. Koch, emeritus professor of astronomy and astrophysics at the University of Pennsylvania, passed away at his home in Ardmore, Pennsylvania on 11 October 2010 after a brief illness. Bob was 80 years old and remained sharp and intellectually engaged with the astronomical community up until the onset of complications from a brain tumor. Bob was born in York, Pennsylvania on 19 December 1929, and graduated from York Catholic High School in 1947. He attended the University of Pennsylvania on a senatorial scholarship, graduating in 1951. After two years in the United States Army, he enrolled in graduate school at the University of Pennsylvania, doing his doctoral research on the photoelectric photometry of R CMa, AO Cas, AS Eri, and XY Leo at the Steward Observatory, University of Arizona in Tucson. Bob would continue this exploration of close binary stars, their atmospheres and interactions, for the rest of his career. Bob met his future spouse, Joanne C. Underwood, while in graduate school in 1957 and they were married in 1959. Bob received his PhD in astronomy in 1959 and moved to Amherst, Massachusetts, where he taught as a member of the Four College Astronomy Department until 1966. Following a year at the University of New Mexico in Albuquerque, Bob joined the Astronomy Department at Penn, teaching and doing research there until his retirement in 1996. Bob's main interests were the study of close and eclipsing binary stars, stellar envelopes and winds, intrinsic variables, transits and occultations, and the Milky Way Galaxy, producing well over 100 refereed publications. Bob was partial to photoelectric photometry and polarimetry, conducting most of his observational research at the University of Pennsylvania Flower and Cook Observatory, and at other ground- and space-based observatories. As an international figure in the area of binary stars, Bob had widespread collaborations with scientists at other institutions, in the US and throughout the world, and

  14. Robert B. Stevens: UCSC Chancellorship, 1987-1991

    OpenAIRE

    Stevens, Robert; Jarrell, Randall; Regional History Project, UCSC Library

    1999-01-01

    The Regional History Project conducted six interviews with UCSC Chancellor Robert B. Stevens during June and July, 1991. Stevens was appointed the campus's fifth chancellor by UC President David P. Gardner in July 1987, and served until July 1991. He was the second UCSC chancellor (following Chancellor Emeritus Robert L. Sinsheimer) recruited from a private institution. Stevens was born in England in 1933 and first came to the United States when he was 23. He was educated at Oxford U...

  15. Leaving Libertarianism: : Social Ties in Robert Nozick's New Philosophy

    OpenAIRE

    2002-01-01

    SUMMARY This thesis Leaving Libertarianism: Social Ties in Robert Nozick s New Philosophy challenges the general and most widespread portrayals of the American philosopher Robert Nozick (1938-2002) by studying the notion of social ties in his later philosophy. The point of departure is the present descriptions of Nozick s philosophy. Mostly these depictions are based upon three postulates: That Nozick is an extreme individualist, that the libertarian Anarchy, State, and Utopia (1...

  16. Caruso St John y Robert Smithson: Interferencias

    Directory of Open Access Journals (Sweden)

    Emilia Hernández Pezzi

    2016-05-01

    Full Text Available Resumen Los discursos cruzados son el soporte común del presente número de Cuadernos. El cruce que planteamos tiene como protagonistas al artista Robert Smithson y a los arquitectos Adam Caruso y Peter St John. Estos últimos hacen mención del trabajo del artista norteamericano para explicar su proyecto de remodelación de Stortorget, la plaza de la catedral en el centro de Kalmar, Suecia. A partir de aquí, comenzamos una exploración del trabajo y las preocupaciones de ambos que nos permite dibujar convergencias y sintonías procesuales por encima de las diferencias temáticas, ideológicas y estilísticas. Al disponer en paralelo la obra de Smithson y Caruso St John descubrimos vibraciones y resonancias que muestran una interacción productiva de sus preocupaciones. La materia se convierte en sus propuestas en un objeto activo y sensible, un depósito energético con el que operar. El traslado de piedras en Stortorget convoca la memoria de la ciudad del mismo modo que el basalto y la sal del Spiral Jetty, erosionados por el tiempo, nos hablan de procesos abiertos. El tiempo y la memoria pasan a ser soportes estratégicos con los que construyen sus miradas. Los objetos se disuelven en las relaciones que establecen con su entorno produciendo equilibrios frágiles e instantáneos. De esta manera el artículo pretende generar un vórtice de reflexión, una espiral en cuyo recorrido se manifiesten las tensiones parciales del cruce propuesto, sus fijezas momentáneas.

  17. Realismo e utopia em Robert Michels

    Directory of Open Access Journals (Sweden)

    Pedro Floriano Ribeiro

    2012-11-01

    Full Text Available O artigo aponta e discute as principais influências teóricas e políticas de Robert Michels na construção de Sociologia dos partidos políticos, tentando ir além das fontes mais conhecidas, como Gaetano Mosca, Vilfredo Pareto, Max Weber e Gustave Le Bon. Como Michels não se preocupou em construir definições claras sobre seus conceitos principais, procurou-se extrair a essência de seu raciocínio, apresentando as concepções e influências teóricas predominantes no livro, e destacando as mudanças entre a primeira edição, de 1911, e a segunda, de 1925. Para tanto, realizou-se um estudo das 989 notas explicativas desta segunda edição (além do texto principal em si. Além de discutir as fontes explicitadas no livro, o artigo também esboça uma "análise genética" da obra, levantando alguns fatos biográficos prévios à sua publicação e no intervalo entre as duas edições, e recorrendo, ainda, a outros trabalhos de Michels. Após debater as concepções e críticas do autor sobre democracia, revolução, socialismo, sindicalismo e anarquismo, o artigo termina com um balanço sobre as fragilidades e contribuições da obra de Michels, destacando que a chave para se compreender vida e obra do autor reside em perceber as tensas disjuntivas estabelecidas entre realismo e utopia e entre o Michels militante e o Michels analista.

  18. On the extended real Clifford-Dirac algebra and new physically meaningful symmetries of the Dirac equations with nonzero mass

    International Nuclear Information System (INIS)

    A 64-dimensional extended real Clifford-Dirac algebra is introduced. On its basis, new pure matrix symmetries of the Dirac equation in the Foldy-Wouthuysen representation was found. Finally, spin 1 Poincare symmetries both for the Foldy-Wouthuysen and standard Dirac equations with nonzero mass are found.

  19. An extension of the dynamics of one-dimensional wave splitting to three dimensions via Clifford algebra

    International Nuclear Information System (INIS)

    The dynamics of split fields in one dimension are extended to three dimensions using Clifford algebra. The solutions of the resulting equations provide a unique insight into wave splitting and allow the construction of wave splittings in three dimensions that may be useful in solving the three-dimensional inverse scattering problem in the time domain

  20. On Chern-Simons (super) gravity, E8 Yang-Mills and polyvector-valued gauge theories in Clifford spaces

    International Nuclear Information System (INIS)

    It is shown how the E8 Yang-Mills theory is a small sector of a Cl(16) algebra gauge theory and why the 11D Chern-Simons (super) gravity theory can be embedded into a Cl(11) algebra gauge theory. These results may shed some light into the origins behind the hidden E8 symmetry of 11D supergravity. To finalize, we explain how the Clifford algebra gauge theory (that contains the Chern-Simons gravity action in D=11, for example) can itself be embedded into a more fundamental polyvector-valued gauge theory in Clifford spaces involving tensorial coordinates xμ1μ2,xμ1μ2μ3,...,xμ1μ2...μD in addition to antisymmetric tensor gauge fields Aμ1μ2,Aμ1μ2μ3,...,Aμ1μ2...μD. The polyvector-valued supersymmetric extension of this polyvector valued bosonic gauge theory in Clifford spaces may reveal more important features of a Clifford-algebraic structure underlying M, F theory.

  1. On modified Weyl-Heisenberg algebras, noncommutativity, matrix-valued Planck constant and QM in Clifford spaces

    International Nuclear Information System (INIS)

    A novel Weyl-Heisenberg algebra in Clifford spaces is constructed that is based on a matrix-valued HAB extension of Planck's constant. As a result of this modified Weyl-Heisenberg algebra one will no longer be able to measure, simultaneously, the pairs of variables (x, px), (x, py), (x, pz), (y, px), ... with absolute precision. New Klein-Gordon and Dirac wave equations and dispersion relations in Clifford spaces are presented. The latter Dirac equation is a generalization of the Dirac-Lanczos-Barut-Hestenes equation. We display the explicit isomorphism between Yang's noncommutative spacetime algebra and the area-coordinates algebra associated with Clifford spaces. The former Yang's algebra involves noncommuting coordinates and momenta with a minimum Planck scale λ (ultraviolet cutoff) and a minimum momentum p ℎ/R (maximal length R, infrared cutoff). The double-scaling limit of Yang's algebra λ → 0, R → ∞, in conjunction with the large n → ∞ limit, leads naturally to the area quantization condition λR = L2 = nλ2 (in Planck area units) given in terms of the discrete angular-momentum eigenvalues n. It is shown how modified Newtonian dynamics is also a consequence of Yang's algebra resulting from the modified Poisson brackets. Finally, another noncommutative algebra which differs from Yang's algebra and related to the minimal length uncertainty relations is presented. We conclude with a discussion of the implications of noncommutative QM and QFT's in Clifford spaces

  2. MD on UFOs at MKIs and MKQs

    CERN Document Server

    Baer, T; Bartmann, W; Bracco, C; Carlier, E; Dehning, B; Garrel, N; Goddard, B; Jackson, S; Jimenez, M; Kain, V; Mertens, V; Misiowiec, M; Nordt, A; Papotti, G; Uythoven, J; Wenninger, J; Zerlauth, M; Zamantzas, C; Zimmermann, F

    2012-01-01

    UFOs ("Unidentified Falling Objects") are expected to be one of the major known performance limitation of the LHC. In this MD, the production mechanism and the dynamics of UFOs at the injection kicker magnets (MKIs) and the tune kicker magnets (MKQs) were studied. This was done by pulsing the MKIs and MKQs on a gap in the partly filled machine. During the MD, in total 58 UFO-type beam loss patterns were observed directly after pulsing the MKIs. None were observed after pulsing the MKQs, which provides important input for possible mitigation strategies. The temporal and spatial distribution of the UFO events could be determined by using a dedicated BLM Study Buffer, the implications for the UFO dynamics are discussed.

  3. Batch By Batch Longitudinal Emittance Blowup MD

    CERN Document Server

    Mastoridis, T; Butterworth, A; Jaussi, M; Molendijk, J

    2012-01-01

    The transverse bunch emittance increases significantly at 450 GeV from the time of injection till the ramp due to IBS. By selectively blowing up the longitudinal emittance of the incoming batch at each injection, it should be possible to reduce the transverse emittance growth rates due to IBS. An MD was conducted on April 22nd 2012 to test the feasibility and performance of the batch-by-batch longitudinal emittance blowup. There were three main goals during the MD. First, to test the developed hardware, firmware, and software for the batch-by-batch blowup. Then, to measure the transverse emittance growth rates of blown-up and "witness" batches to quantify any improvement, and finally to test the ALLInjectSequencer class, which deals with the complicated gymnastics of introducing or masking the new batch to various RF loops.

  4. Integrative Medicine Program- MD Anderson Cancer Center

    OpenAIRE

    Lee, Richard T.

    2012-01-01

    The Integrative Medicine Program at MD Anderson Cancer Center was first established in 1998.  Our mission is to empower patients with cancer and their families to become active partners in their own physical, psycho-spiritual, and social health through personalized education and evidenced-based clinical care to optimize health, quality of life, and clinical outcomes across the cancer continuum.  The program consists of three main components: clinical care, research, and education.  The Integr...

  5. Ashley W. Oughterson, MD: Surgeon, Soldier, Leader

    OpenAIRE

    Kunstman, John W.; Longo, Walter E

    2015-01-01

    Ashley W. Oughterson, MD, (1895-1956) was a longtime faculty surgeon at Yale University. He performed some of the earliest pancreatic resections in the United States. During World War II, Colonel Oughterson was the primary “Surgical Consultant” in the South Pacific and present at nearly every major battle. His meticulously kept diary is regarded as the foremost source detailing wartime surgical care. Colonel Oughterson led the initial Army team to survey Hiroshima and Nagasaki following the n...

  6. Robert Lowell’s Culturally Coded Lexis

    Directory of Open Access Journals (Sweden)

    Lidija Davidovska

    2014-12-01

    Full Text Available In this paper, I will examine how a vital ele­ment of Robert Lowell’s descriptive and narrative struc­tures, i.e., the lexis, promise to unfold the “layers” of the culture that served as context for Life Studies. This in­volves exploring both the denotations and connotations of his culturally encoded lexis, that is, the external mean­ings of certain words and phrases before they “en­ter” the poem and the internal meanings they acquire after entering the poem. This process of “verbal osmo­sis”, when words absorb meaning from these different contexts, is, what I believe, critic and linguist Winifred Nowottny describes as “give and take between those patterns” (Fowler, 2009: 31. My analysis will focus on the sociolinguistic patina accrued on certain units of Lowell’s poetic lexis, such as names of historical people, events and concepts belonging to American and Euro­pean spiritual cultures and traditions, as well as brand names from popular material culture of the first half of the twentieth century. The analysis will also dwell on the use of idioms, catch phrases and other verbal clichés which reflect the culture that generated them. They func­tion as verbal “ready-mades” that additionally rein­force Lowell’s well-known anecdotal, colloquial and infor­mal poetic language. The choice of these particular lexical items is significant as they reflect the categoriza­tion of the world and the experience of the poetic voice or the “language user” in broader linguistic terms. At the same time, the categorization of the experience reflects the ideational position, the worldview of the language user. In the context of his poetics of immanence and experi­ence, this culturally coded poetic diction is ana­lyzed as another authentic and documented presenta­tion of immanent narrator’s “lived experience”.

  7. Obituary: Peter Robert Wilson, 1929-2007

    Science.gov (United States)

    Snodgrass, Herschel B.

    2009-01-01

    It is with great sadness that I report the passing of Peter Robert Wilson, a well-known and well-loved figure in the solar physics community. Peter was on the faculty of the Department of Applied Mathematics at the University of Sydney for 39 years, and Chair of the department for 24 of these years. He was the author or co-author of more than 80 scientific research papers and a book, Solar and Stellar Activity Cycles (1994), published by Cambridge University Press. He died suddenly of a heart attack, at his home in Glebe, Australia, in the early morning of 11 November 2007. Peter was an organizer of, and participant in, many international conferences and workshops. He traveled extensively, holding visiting appointments at the University of Colorado (JILA), at Cambridge University, at the College de France (Paris), and at the California Institute of Technology [CalTech]. Most of his work was in the field of solar physics, but he also did some work on the philosophy of science and on tides. Peter came from a line of mathematicians. His father, Robert Wilson, immigrated to Australia from Glasgow in 1911, and became a mathematics teacher at Scotch College, a private school in Melbourne. There his name was changed to 'Bill' because 'Bob' was already taken." Peter's enjoyment of this story as characteristic of Australian academia (as any fan of Monty Python would understand) is indicative of his infectious sense of humor. In a similar vein, he claimed ancestry traced back to the eighteenth-century Scottish mathematician Alexander Wilson, Professor of Astronomy at the University of Glasgow. That Wilson is famous in the solar physics community for his discovery, known as the "Wilson Effect," of the photospheric depressions associated with sunspots. Peter himself could not resist writing a paper on this subject, and was delighted when the bait was taken by some less-informed colleagues who chided him for "naming an effect after himself." "Bill" Wilson married Naomi

  8. 77 FR 73967 - Drawbridge Operation Regulation; Bear Creek, Dundalk, MD

    Science.gov (United States)

    2012-12-12

    ... Regulation; Bear Creek, Dundalk, MD'' in the Federal Register (77 FR 5201). The rulemaking concerned would... SECURITY Coast Guard 33 CFR Part 117 RIN 1625-AA09 Drawbridge Operation Regulation; Bear Creek, Dundalk, MD... highway bridge at Wise Avenue across Bear Creek, mile 3.4, between Dundalk and Sparrows Point, MD....

  9. Kaluza-Klein-Carmeli Metric from Quaternion-Clifford Space, Lorentz' Force, and Some Observables

    Directory of Open Access Journals (Sweden)

    Christianto V.

    2008-04-01

    Full Text Available It was known for quite long time that {a} quaternion space can be generalized to {a} Clifford space, and vice versa; but how to find its neat link with more convenient metric form in {the} General Relativity theory, has not been explored extensively. We begin with a representation of group with non-zero quaternions to derive closed FLRW metric, and from there obtains Carmeli metric, which can be extended further to become 5D and 6D metric (which we propose to call Kaluza-Klein-Carmeli metric. Thereafter we discuss some plausible implications of this metric, beyond describing a galaxy's spiraling motion and redshift data as these have been done by Carmeli and Hartnett. In subsequent section we explain Podkletnov's rotating disc experiment. We also note possible implications to quantum gravity. Further observations are of course recommended in order to refute or verify this proposition.

  10. PT-symmetry, Cartan decompositions, Lie triple systems and Krein space-related Clifford algebras

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, Uwe [Research Center Dresden-Rossendorf, PO Box 510119, D-01314 Dresden (Germany); Kuzhel, Sergii, E-mail: u.guenther@fzd.d, E-mail: kuzhel@imath.kiev.u [Institute of Mathematics of the NAS of Ukraine, 01601 Kyiv (Ukraine)

    2010-10-01

    Gauged PT quantum mechanics (PTQM) and corresponding Krein space setups are studied. For models with constant non-Abelian gauge potentials and extended parity inversions compact and noncompact Lie group components are analyzed via Cartan decompositions. A Lie-triple structure is found and an interpretation as PT-symmetrically generalized Jaynes-Cummings model is possible with close relation to recently studied cavity QED setups with transmon states in multilevel artificial atoms. For models with Abelian gauge potentials a hidden Clifford algebra structure is found and used to obtain the fundamental symmetry of Krein space-related J-self-adjoint extensions for PTQM setups with ultra-localized potentials. (fast track communication)

  11. The Clifford algebra of nonrelativistic phase space and the concept of mass

    International Nuclear Information System (INIS)

    Prompted by a recent demonstration that the structure of a single quark-lepton generation may be understood via a Dirac-like linearization of the form p2 + x2, we analyse the corresponding Clifford algebra in some detail. After classifying all elements of this algebra according to their U(1) x SU(3) and SU(2) transformation properties, we identify the element which might be associated with the concept of lepton mass. This element is then transformed into a corresponding element for a single coloured quark. It is shown that-although none of the three thus obtained individual quark mass elements is rotationally invariant-the rotational invariance of the quark mass term is restored when the sum over quark colours is performed

  12. A Clifford Algebra Approach to the Classical Problem of a Charge in a Magnetic Monopole Field

    Science.gov (United States)

    Vaz, Jayme

    2013-05-01

    The motion of an electric charge in the field of a magnetic monopole is described by means of a Lagrangian model written in terms of the Clifford algebra of the physical space. The equations of motion are written in terms of a radial equation (involving r=| r|, where r( t) is the charge trajectory) and a rotor equation (written in terms of an unitary operator spinor R). The solution corresponding to the charge trajectory in the field of a magnetic monopole is given in parametric form. The model can be generalized in order to describe the motion of a charge in the field of a magnetic monopole and other additional central forces, and as an example, we discuss the classical ones involving linear and inverse square interactions.

  13. New insights in the standard model of quantum physics in Clifford algebra

    CERN Document Server

    Daviau, Claude

    2013-01-01

    Why Clifford algebra is the true mathematical frame of the standard model of quantum physics. Why the time is everywhere oriented and why the left side shall never become the right side. Why positrons have also a positive proper energy. Why there is a Planck constant. Why a mass is not a charge. Why a system of particles implies the existence of the inverse of the individual wave function. Why a fourth neutrino should be a good candidate for black matter. Why concepts as “parity” and “reverse” are essential. Why the electron of a H atom is in only one bound state. Plus 2 very remarkable identities, and the invariant wave equations that they imply. Plus 3 generations and 4 neutrinos. Plus 5 dimensions in the space and 6 dimensions in space-time…

  14. Families of isospectral matrix Hamiltonians by deformation of the Clifford algebra on a phase space

    International Nuclear Information System (INIS)

    By using a recently developed method, we report five different families of isospectral 2 x 2 matrix Hamiltonians defined on a four-dimensional (4D) phase space. The employed method is based on a realization of the supersymmetry idea on the phase space whose complexified Clifford algebra structure is deformed with the Moyal star-product. Each reported family comprises many physically relevant special models. 2D Pauli Hamiltonians, systems involving spin-orbit interactions such as Aharonov-Casher-type systems, a supermembrane toy model and models describing motion in noncentral electromagnetic fields as well as Rashba- and Dresselhaus-type systems from semiconductor physics are obtained, together with their super-partners, as special cases. A large family of isospectral systems characterized by the whole set of analytic functions is also presented.

  15. PT-symmetry, Cartan decompositions, Lie triple systems and Krein space-related Clifford algebras

    International Nuclear Information System (INIS)

    Gauged PT quantum mechanics (PTQM) and corresponding Krein space setups are studied. For models with constant non-Abelian gauge potentials and extended parity inversions compact and noncompact Lie group components are analyzed via Cartan decompositions. A Lie-triple structure is found and an interpretation as PT-symmetrically generalized Jaynes-Cummings model is possible with close relation to recently studied cavity QED setups with transmon states in multilevel artificial atoms. For models with Abelian gauge potentials a hidden Clifford algebra structure is found and used to obtain the fundamental symmetry of Krein space-related J-self-adjoint extensions for PTQM setups with ultra-localized potentials. (fast track communication)

  16. Vector coherent states from Plancherel's theorem, Clifford algebras and matrix domains

    International Nuclear Information System (INIS)

    As a substantial generalization of the technique for constructing canonical and the related nonlinear and q-deformed coherent states, we present here a method for constructing vector coherent states (VCS) in the same spirit. These VCS may have a finite or an infinite number of components. The resulting formalism, which involves an assumption on the existence of a resolution of the identity, is broad enough to include all the definitions of coherent states existing in the current literature, subject to this restriction. As examples, we first apply the technique to construct VCS using the Plancherel isometry for groups and VCS associated with Clifford algebras, in particular quaternions. As physical examples, we discuss VCS for a quantum optical model and finally apply the general technique to build VCS over certain matrix domains

  17. Turbulence intermittency, vector multifractals and Lie cascades generated by stochastic Clifford algebra

    Science.gov (United States)

    Schertzer, Daniel; Tchiguirinskaia, Ioulia

    2014-05-01

    A complex key feature of turbulence is that the velocity is a vector field, whereas intermittency, another key feature, has been mostly understood, analysed and simulated in scalar frameworks. This gap has prevented many developments. Some years ago, the general framework of 'Lie cascades' was introduced (Schertzer and Lovejoy, 1993) to deal with both features by considering cascades generated by stochastic Lie algebra. However, the theoretical efforts were mostly concentrated on the decomposition of this algebra into its radical and a semi-simple algebra and faced too many degrees of freedom. In this communication, we show that the class of Clifford algebra is already wide enough, very convenient and physically meaningful to understand, analyse and simulate intermittent vector fields.

  18. Kaluza-Klein-Carmeli Metric from Quaternion-Clifford Space, Lorentz' Force, and Some Observables

    Directory of Open Access Journals (Sweden)

    Christianto V.

    2008-04-01

    Full Text Available It was known for quite long time that a quaternion space can be generalized to a Clifford space, and vice versa; but how to find its neat link with more convenient metric form in the General Relativity theory, has not been explored extensively. We begin with a representation of group with non-zero quaternions to derive closed FLRW metric [1], and from there obtains Carmeli metric, which can be extended further to become 5D and 6D metric (which we propose to call Kaluza-Klein-Carmeli metric. Thereafter we discuss some plausible implications of this metric, beyond describing a galaxy’s spiraling motion and redshift data as these have been done by Carmeli and Hartnett [4, 5, 6]. In subsequent section we explain Podkletnov’s rotating disc experiment. We also note possible implications to quantum gravity. Further observations are of course recommended in order to refute or verify this proposition.

  19. ["The piano trio" Robert Schumann, Clara Schumann and Johannes Brahms].

    Science.gov (United States)

    Albretsen, C S

    1998-12-10

    The relationship between the pianist and composer Clara Schumann and the composers Robert Schumann and Johannes Brahms has for a century been an interesting topic. Clara and Robert Schumann both suffered separation from their mothers during early childhood. Johannes Brahms was intensely spoiled by his mother. Robert Schumann needed a structuring wife in his adult life, while Johannes Brahms turned to be afraid of intrusive women. Robert Schumann's psychotic breakdown in February 1854 had a complex background: a hypomanic state, some marital problems, a stressful journey with musical appearances, and possibly a difficulty in differentiating between himself and his new friend Johannes Brahms. As for Clara Schumann, who lost her mother before the age of five, musical activities became her way of overcoming the difficulties of life. She was able to support Robert in his lunatic asylum and their seven children growing up in three separate towns. The chronic diseases of the sons: schizophrenia, polyarthritis and tuberculosis made a deep impression on her and her fingers and hands were periodically immobilised with severe pain. For four decades Johannes was her able "son" and Clara was his "mother", at a safe distance. PMID:9914757

  20. Geometrical treatment of Clifford algebras and spinors with applications to the dynamics of spin particles

    International Nuclear Information System (INIS)

    The algebraic structure of the real Clifford algebras (CA) of vector spaces with non-degenerated scalar product of arbitrary signature is studied, and a classification formula for this is obtained. The latter is based on three sequences of integer numbers from which one is the Radon-Harwitz sequence. A new representation method of real CA is constructed. This leads to a geometrical representation of real Clifford algebras in which the representation spaces are subspaces of the CA itself (''spinor spaces''). One of these spinor spaces is a subalgebra of the original CA. The relation between CA and external algebras is studied. Each external algebra with a scalar product possesses the structure of a CA. From the geometric representation developed here then follows that spinors are inhomogeneous external forms. The transformation behaviour of spinors under the orthogonal, as well as under the general linear group is studied. By means of these algebraic results the spinor connexion and the covariant Dirac operator on a differential manifold are introduced. In the geometrical representation a further in ternal SL(2,R) symmetry of the Dirac equation (DE) is shown. Furthermore other equivalent formulations of the DE can be obtained. Of special interest is the tetrade formulation of the DE. A generalization of the DE is introduced. The equations of motion of the classical relativistic spin particle are derived by means of spinors and CA from a variational principle. From this interesting formal analogies with the supersymmetric theories of the spin particle result. Finally the DE in the curved space-time is established and studied in the tetrade formulation. Using the methods developed here a new exact solution of the coupled Einstein-Curtan-Dirac theory was found (massice ''Ghost-Dirac fields''). (orig.)

  1. Farewell party for Annick Lyraud and Robert Aymar

    International Nuclear Information System (INIS)

    Although Robert Aymar will only take up his position as Director-General of CERN in January 2004, he formally gave up leadership of ITER at the end of June 2003, with the transfer of that responsibility to Yasuo Shimomura. After the summer he will devote the lion's share of his efforts to his new job. The International Team therefore held a party to say farewell to him, as well as to Annick Lyraud, who will move in September to CERN to continue to support him there. Robert and Annick were on the receiving end of three speeches. Yasuo Shimomura paid tribute to Robert's dedication to the ITER cause from the time well before he became ITER Director, confirming that without his leadership the ITER project would not be in its present expectant state

  2. A higher-order Robert-Asselin type time filter

    Science.gov (United States)

    Li, Yong; Trenchea, Catalin

    2014-02-01

    The Robert-Asselin (RA) time filter combined with leapfrog scheme is widely used in numerical models of weather and climate. It successfully suppresses the spurious computational mode associated with the leapfrog method, but it also weakly dampens the physical mode and degrades the numerical accuracy. The Robert-Asselin-Williams (RAW) time filter is a modification of the RA filter that reduces the undesired numerical damping of RA filter and increases the accuracy. We propose a higher-order Robert-Asselin (hoRA) type time filter which effectively suppresses the computational modes and achieves third-order accuracy with the same storage requirement as RAW filter. Like RA and RAW filters, the hoRA filter is non-intrusive, and so it would be easily implementable. The leapfrog scheme with hoRA filter is almost as accurate, stable and efficient as the intrusive third-order Adams-Bashforth (AB3) method.

  3. Integrative Medicine Program- MD Anderson Cancer Center

    Directory of Open Access Journals (Sweden)

    Richard T Lee

    2012-06-01

    Full Text Available The Integrative Medicine Program at MD Anderson Cancer Center was first established in 1998.  Our mission is to empower patients with cancer and their families to become active partners in their own physical, psycho-spiritual, and social health through personalized education and evidenced-based clinical care to optimize health, quality of life, and clinical outcomes across the cancer continuum.  The program consists of three main components: clinical care, research, and education.  The Integrative Medicine Center provides clinical services to patients through individual and group programs.  The clinical philosophy of the center is to work collaboratively with the oncology teams to build comprehensive and integrative care plans that are personalized, evidence-based, and safe with the goal of improving clinical outcomes.  The individual services comprise of integrative oncology consultation, acupuncture, meditation, music therapy, nutrition, and oncology massage.  The center also provides a variety of group programs including meditation, yoga, tai chi, cooking classes and others.  Over the past 13 years, over 70,000 patients and families have participated in services and programs offered by the center.  The research portfolio focuses on three main areas: mind-body interventions, acupuncture, and meditation.  This lecture will focus on providing an overview of the Integrative Medicine Program at MD Anderson with a focus on the clinical services provided.  Participants will learn about the integrative clinical model and how this is applied to the care of cancer patients at MD Anderson Cancer Center.  Current and future research topics will be discussed as well as patient cases.

  4. MD Test of a Ballistic Optics

    CERN Document Server

    Garcia-Tabares Valdivieso, Ana; Salvachua Ferrando, Belen Maria; Skowronski, Piotr Krzysztof; Solfaroli Camillocci, Matteo; Tomas Garcia, Rogelio; Wenninger, Jorg; Coello De Portugal - Martinez Vazquez, Jaime Maria; CERN. Geneva. ATS Department

    2016-01-01

    The ballistic optics is designed to improve the understanding of optical errors and BPM systematic effects in the critical triplet region. The particularity of that optics is that the triplet is switched off, effectively transforming the triplets on both sides of IR1 and IR5 into drift spaces. Advantage can be taken from that fact to localize better errors in the Q4-Q5-triplet region. During this MD this new optics was tested for the first time at injection with beam 2.

  5. ProtoMD: A prototyping toolkit for multiscale molecular dynamics

    Science.gov (United States)

    Somogyi, Endre; Mansour, Andrew Abi; Ortoleva, Peter J.

    2016-05-01

    ProtoMD is a toolkit that facilitates the development of algorithms for multiscale molecular dynamics (MD) simulations. It is designed for multiscale methods which capture the dynamic transfer of information across multiple spatial scales, such as the atomic to the mesoscopic scale, via coevolving microscopic and coarse-grained (CG) variables. ProtoMD can be also be used to calibrate parameters needed in traditional CG-MD methods. The toolkit integrates 'GROMACS wrapper' to initiate MD simulations, and 'MDAnalysis' to analyze and manipulate trajectory files. It facilitates experimentation with a spectrum of coarse-grained variables, prototyping rare events (such as chemical reactions), or simulating nanocharacterization experiments such as terahertz spectroscopy, AFM, nanopore, and time-of-flight mass spectroscopy. ProtoMD is written in python and is freely available under the GNU General Public License from github.com/CTCNano/proto_md.

  6. Double trisomy (48,XXX,+18) with features of Roberts syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Descartes, M.; Longshore, J.W.; Crawford, E. [Univ. of Alabama, Birmingham, AL (United States)] [and others

    1994-09-01

    We report an infant with double trisomy 48,XXX,+18, who also displayed features of Roberts syndrome. All previously published cases with similar double trisomy have presented with features of trisomy 18 syndrome. The chromosome analysis done at birth revealed the double trisomy; parental chromosomes were normal. The proband presented with microbrachycephaly, unilateral cleft lip and palate, choanal atresia, midfacial capillary hemanioma, thin nares, shallow orbits, malformed ears, sparse hair, hypomelia of the upper limbs, rocker-bottom feet, auricular septal defect and agenesis of the corpus callosum. Characteristic features of Roberts syndrome included hypomelia, midfacial defects, and severe growth deficiency. Among the many different features reported in the literature for patients with trisomy 18 syndrome, the most consistent were growth deficiency, clenched fingers and congenital heart defects (e.g. VSD, ASD, PDA). Although some of our patient`s features such as cleft lip and cleft palate, low-set malformed ears, ASD, defects of the corpus callosum, choanal atresia, radial aplasia could also be seen in trisomy 18 syndrome (in 10-50% of the cases), her phenotype was more typical of Roberts syndrome because of symmetrical hypomelia and midfacial defects. Our patient`s chromosomes did not show premature separation of centromeric heterochromatin, a feature reported to occur in approximately one-half of individuals with Roberts syndrome. Sporadic aneuploidy involving different chromosomes has been found in lymphocyte cultures from some Roberts syndrome patients and is considered by some authors as a mitotic mutant. This aneuploidy is most likely to be chromosome gain. The simultaneous occurrence of trisomy X and 18 is extremely rare with only 11 cases having been reported in the literature. Our patient is unique since she has the double trisomy in addition to the characteristic features of Roberts syndrome.

  7. Dr Robert Proust: a gynaecologist's contribution to world literature.

    Science.gov (United States)

    de Costa, Caroline

    2013-09-01

    Dr Robert Proust, though overshadowed in history by his more famous brother, the novelist Marcel Proust, was an eminent and innovative French surgeon who achieved recognition largely as a gynaecologist, but also was an accomplished urologist and general surgeon. He was the author of a textbook, The surgery of the female genital tract, that was very successful in his lifetime and ran to six editions. He was always very supportive of his brother's writing, and after Marcel's premature death Robert edited and arranged for publication of the final three volumes of his novel À la recherche du temps perdu, which has been called the greatest novel of the twentieth century. PMID:23820137

  8. Obituary: Robert Fleischer, 1918-2001

    Science.gov (United States)

    Boyce, Peter Bradford; Saffell, Mary E.

    2003-12-01

    Robert Fleischer was born 20 August 1918 to Leon and Rose Fleischer in Flushing, NY. He was educated at Harvard, receiving his BS in 1940, MA in 1947, and PhD in 1949. He specialized in geophysics and solar-terrestrial relations. Fleischer joined the faculty at Rensselaer Polytechnic Institute advancing from Assistant to Full professor in 1958. As Director of the RPI Observatory, Fleischer attempted to bring modern astronomy to the institutions in the Albany area by procuring the funds to build a radio telescope. He left for the National Science Foundation (NSF) before the observatory was completed. It is a testament to his character that without his enormous energy, organizational, and fundraising abilities, the radio telescope project languished after he left. Fleischer joined the NSF in 1962 as the Program Director for Solar-Terrestrial Research. He was the government-wide Coordinator for the International Quiet Sun Years, and coordinated the 1966 South American Eclipse expeditions. Thereafter, he was appointed Deputy Head of the Office of International Science Activities. Fleischer is most notably remembered as the head of the Astronomy Section at the National Science Foundation. He brought astronomy into its own at NSF and involved the community in a major way through use of advisory committees. He was dedicated to helping the astronomical community understand the funding system, the political environment, and the various factors in how money is allocated. Fleischer truly believed in the concept that scientists should be making the important decisions about their field. He was instrumental in injecting science into the oversight of the National Observatories. Relations with the community say a lot about the man, the complexities of his character, and the forces that drove him. Fleischer was passionate in his beliefs and in his devotion to doing the best for astronomy. His strong approach and belief in himself served him well in many ways, but caused him grief

  9. Obituary: Robert C. Bless (1927 - 2015)

    Science.gov (United States)

    Surrounded by his loving family, Robert Charles Bless died at home on November 29th, three days before his 88th birthday. He was born in Ithaca, NY on Dec. 3, 1927 to a Russian father, Arthur Aaron Bless, and a French mother, Eva Chantrell Bless. Bob spent many summers on the family farm in the South of France, where he gained a great pride and joy in his French heritage, large extended family, and mother tongue. As a child growing up in Gainesville, FL, Bob's first job was snake wrangling, earning 10 cents per foot, with an added bonus for the more venomous species. Young Robbie took daily adventures in the Florida woods and swamps, armed only with pockets full of pecans and oranges. He enjoyed spending time at the family's lake cabin, where he learned to sail and helped his father plant acres of trees to grow their timber plantation. As a first generation immigrant, Bob's father received a PhD in physics, which inspired Bob to pursue an extensive educational route in astrophysics. Bob excelled in academics, graduating high school at the age of 16 and the University of Florida (B.Sc.) at 19. His path to graduate school was interrupted by a diagnosis of tuberculosis that forced him into a Florida sanitorium for one year. During this time, Bob made the most of what he described as the most dismal part of life by advocating for patient rights, initiating an inter-sanitorium newsletter, and gaining skills and experience in community organization and leadership - qualities that would later inform his leadership in academe. After being one of the first successfully treated tuberculosis patients in the US, Bob went on to earn a M.Sc. from Cornell University, and received his PhD degree in Astronomy from the University of Michigan in 1958. That same year, Bob joined the staff of the Astronomy Department of the University of Wisconsin (UW), Madison. It was there that Bob met Diane McQueen. Despite Bob's Dodge Dart and what has been described as the worst first date in

  10. Clifford代数Clp,q的中心子代数%The Central Subalgebra of Clifford Algebra Clp,q

    Institute of Scientific and Technical Information of China (English)

    宋元凤; 李武明; 丁宝霞

    2011-01-01

    (p,q)型Minkowski空间Rp,q的Clifford代数Clp-q是一类2p+q维的实结合代数,当p+q〉1时是非交换代数.文中讨论了Clp-q的中心Cen(Clp,q)的相关性质,利用基元的Clifford积导出由p,q确定Clp,q中心的公式.%Clifford algebra Clp,q of (p,q) Minkowski space R p,qare a class of2p+qdimension real associative algebra, as p + q 〉 1 , they are non - commutative algebra. The properties of Clp,q center Cen (Clp,q) are discussed by using Clifford product to derive the formula of Clp,q center.

  11. 75 FR 69862 - Airworthiness Directives; MD Helicopters, Inc. Model MD900 Helicopters

    Science.gov (United States)

    2010-11-16

    ... exist or develop on other helicopters of the same type design. Therefore, this AD requires, within 4...-AD. Applicability: Model MD900 helicopters, with lower main rotor hub (hub), part number 900R2101008... the main rotor hub (hub) for a crack. If a crack is found, this AD requires, before further...

  12. 76 FR 41662 - Airworthiness Directives; MD Helicopters, Inc. Model MD900 Helicopters

    Science.gov (United States)

    2011-07-15

    ... helicopters of this same type design. AD Requirements This AD requires a visual inspection, and if necessary...) Inspect the main rotor lower hub assembly for a crack by following the specified portions of MD Helicopter... rotor lower hub assembly (lower hub) for a crack, and if you find a crack, before further...

  13. 76 FR 1993 - Airworthiness Directives; The Boeing Company Model DC-9-81 (MD-81), DC-9-82 (MD-82), DC-9-83 (MD...

    Science.gov (United States)

    2011-01-12

    ... (75 FR 34661). That NPRM proposed to require installing fuel level float and pressure switch in-line... 12866, (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034... Maintenance Manual (AMM) defueling procedure MD80 AMM 12-13-00. The correct reference is Boeing MD80 AMM...

  14. Clifford algebra is the natural framework for root systems and Coxeter groups. Group theory: Coxeter, conformal and modular groups

    CERN Document Server

    Dechant, Pierre-Philippe

    2016-01-01

    In this paper, we make the case that Clifford algebra is the natural framework for root systems and reflection groups, as well as related groups such as the conformal and modular groups: The metric that exists on these spaces can always be used to construct the corresponding Clifford algebra. Via the Cartan-Dieudonn\\'e theorem all the transformations of interest can be written as products of reflections and thus via `sandwiching' with Clifford algebra multivectors. These multivector groups can be used to perform concrete calculations in different groups, e.g. the various types of polyhedral groups, and we treat the example of the tetrahedral group $A_3$ in detail. As an aside, this gives a constructive result that induces from every 3D root system a root system in dimension four, which hinges on the facts that the group of spinors provides a double cover of the rotations, the space of 3D spinors has a 4D euclidean inner product, and with respect to this inner product the group of spinors can be shown to be cl...

  15. Robert Grosseteste's thought on Light and Form of the World

    CERN Document Server

    Sparavigna, Amelia Carolina

    2014-01-01

    Robert Grosseteste was one of the most prominent thinkers of the Thirteenth Century. Philosopher and scientist, he proposed a metaphysics based on the propagation of light. In this framework, he gave a cosmology too. Here we will discuss the treatise where Grosseteste proposed it, that entitled 'De luce, seu de incohatione formarum', 'On Light and the Beginning of Forms'.

  16. The Inharmonious Conflicts in Robert Frost’s Poetry

    Institute of Scientific and Technical Information of China (English)

    杨苗

    2015-01-01

    Robert Frost is one of the most distinguished poets,most of his poems are about the inharmonious relationship between nature and men,Conflicts are like a "thread" appearing in his poems.Frost’s true philosophy on men and life contributes to his wisdom and artistic poems.Frost tries to illustrate the conflict between nature and men in philosophy concern.

  17. Zombilood / Robert Kirkman ; intervjueerinud Margit Tõnson, Peeter Helme

    Index Scriptorium Estoniae

    Kirkman, Robert

    2010-01-01

    Režissöör George A. Romero kultusfilmid zombidest "Elavate surnute öö", "Surnute koidik", "Surnute päev" jpt. on inspiratsiooniks koomiksikirjutaja Robert Kirklandile. Režissöör Frank Darabont on teinud tema tuntuimast koomiksiseeriast "The Walking Dead" teleseriaali "Kõndivad surnud". Zombiteema kasvavast populaarsusest ning intervjuu koomiksikirjutajaga

  18. Robert Bostrom's Contribution to Listening in Organizational Contexts

    Science.gov (United States)

    Brownell, Judi

    2013-01-01

    Robert Bostrom has not only left a listening legacy, but he was also a pioneer in the larger discipline of communication. Bostrom was one of the first scholars to focus on the dynamics of interpersonal contexts, thereby directly contributing to the transition of our field from "speech" to "communication." Early on he recognized the importance of…

  19. Robert Moses procurement and model tests a contractor's perspective

    International Nuclear Information System (INIS)

    This paper discusses the need to provide realistic cost/benefit evaluation criteria in turbine bid specifications and the benefits of competitive model testing. Recent procurement and model test efforts for the Robert Moses Niagara Power Project are used to illustrate these topics

  20. Wikinews interviews World Wide Web co-inventor Robert Cailliau

    CERN Multimedia

    2007-01-01

    "The name Robert Caillau may not ring a bell to the general pbulic, but his invention is the reason why you are reading this: Dr. Cailliau together with his colleague Sir Tim Berners-Lee invented the World Wide Web, making the internet accessible so it could grow from an academic tool to a mass communication medium." (9 pages)

  1. Conceptualising Childhood: Robert Louis Stevenson's "A Child's Garden of Verses."

    Science.gov (United States)

    Webb, Jean

    2002-01-01

    Discusses the construct of childhood in Robert Louis Stevenson's collection of poems, "A Child's Garden of Verses," by employing notions of child development drawn from Jean Piaget and Lev Vygotsky. Finds, from a literary perspective, Stevenson's collection located on the boundaries of romanticism and modernism. (BT)

  2. 77 FR 64506 - Robert D. Willis Hydropower Rate

    Science.gov (United States)

    2012-10-22

    ... Register, (77 FR 40609), of the proposed rate increase for the Willis project. Southwestern provided a 30... proposed Willis power rate were announced by a Federal Register notice published on July 10, 2012 (77 FR... Southwestern Power Administration Robert D. Willis Hydropower Rate AGENCY: Southwestern Power...

  3. Robert Aymar seals the last interconnect in the LHC

    CERN Multimedia

    Maximilien Brice

    2007-01-01

    The LHC completes the circle. On 7 November, in a brief ceremony in the LHC tunnel, CERN Director General Robert Aymar (Photo 1) sealed the last interconnect between the main magnets of the Large Hadron Collider (LHC). Jean-Philippe Tock, leader of the Interconnections team, tightens the last bolt (Photos 4-8).

  4. Paul Robert Wendt: Programmed Instruction and Visual Literacy Pioneer.

    Science.gov (United States)

    Moore, David M.; Bedient, Douglas

    2000-01-01

    Provides a profile of Paul Robert Wendt who was interested in using technology to teach students how to succeed in higher education by improving library and information skills. Highlights include his educational background; work in films; teaching in higher education at Southern Illinois University (SIU); work in programmed instruction and visual…

  5. Measuring What Matters: Robert Sternberg's Enlightened Approach to Admissions Testing

    Science.gov (United States)

    Grace, Catherine O'Neill

    2011-01-01

    Psychologist Robert J. Sternberg's conviction that American standardized testing does not accurately reflect a child's intelligence or potential is far from theoretical. As an elementary school student in the 1950s, he scored poorly on the ubiquitous IQ test of the time, freezing up when the school psychologist entered the room. Thankfully for…

  6. ProtoMD: A prototyping toolkit for multiscale molecular dynamics

    Science.gov (United States)

    Somogyi, Endre; Mansour, Andrew Abi; Ortoleva, Peter J.

    2016-05-01

    ProtoMD is a toolkit that facilitates the development of algorithms for multiscale molecular dynamics (MD) simulations. It is designed for multiscale methods which capture the dynamic transfer of information across multiple spatial scales, such as the atomic to the mesoscopic scale, via coevolving microscopic and coarse-grained (CG) variables. ProtoMD can be also be used to calibrate parameters needed in traditional CG-MD methods. The toolkit integrates 'GROMACS wrapper' to initiate MD simulations, and 'MDAnalysis' to analyze and manipulate trajectory files. It facilitates experimentation with a spectrum of coarse-grained variables, prototyping rare events (such as chemical reactions), or simulating nanocharacterization experiments such as terahertz spectroscopy, AFM, nanopore, and time-of-flight mass spectroscopy. ProtoMD is written in python and is freely available under the GNU General Public License from

  7. Climate and weather across scales: singularities and stochastic Levy-Clifford algebra

    Science.gov (United States)

    Schertzer, Daniel; Tchiguirinskaia, Ioulia

    2016-04-01

    There have been several attempts to understand and simulate the fluctuations of weather and climate across scales. Beyond mono/uni-scaling approaches (e.g. using spectral analysis), this was done with the help of multifractal techniques that aim to track and simulate the scaling singularities of the underlying equations instead of relying on numerical, scale truncated simulations of these equations (Royer et al., 2008, Lovejoy and Schertzer, 2013). However, these techniques were limited to deal with scalar fields, instead of dealing directly with a system of complex interactions and non trivial symmetries. The latter is unfortunately indispensable to answer to the challenging question of being able to assess the climatology of (exo-) planets based on first principles (Pierrehumbert, 2013) or to fully address the question of the relevance of quasi-geostrophic turbulence and to define an effective, fractal dimension of the atmospheric motions (Schertzer et al., 2012). In this talk, we present a plausible candidate based on the combination of Lévy stable processes and Clifford algebra. Together they combine stochastic and structural properties that are strongly universal. They therefore define with the help of a few physically meaningful parameters a wide class of stochastic symmetries, as well as high dimensional vector- or manifold-valued fields respecting these symmetries (Schertzer and Tchiguirinskaia, 2015). Lovejoy, S. & Schertzer, D., 2013. The Weather and Climate: Emergent Laws and Multifractal Cascades. Cambridge U.K. Cambridge Univeristy Press. Pierrehumbert, R.T., 2013. Strange news from other stars. Nature Geoscience, 6(2), pp.81-83. Royer, J.F. et al., 2008. Multifractal analysis of the evolution of simulated precipitation over France in a climate scenario. C.R. Geoscience, 340(431-440). Schertzer, D. et al., 2012. Quasi-geostrophic turbulence and generalized scale invariance, a theoretical reply. Atmos. Chem. Phys., 12, pp.327-336. Schertzer, D

  8. Robert Putnam : miks peaksime naabritega rohkem rääkima? / Robert Putnam ; interv. Külli-Riin Tigasson

    Index Scriptorium Estoniae

    Putnam, Robert

    2006-01-01

    26. mail Tallinnas toimuva Avatud Ühiskonna Foorumi peaesineja, Harvardi Ülikooli professor väidab, et mida paremini tuntakse oma naabreid, mida aktiivsemalt osaletakse kohalikus elus ning mida rohkem inimesed omavahel suhtlevad, seda paremaks ja turvalisemaks muutub nende elukeskkond. Lisad: Robert Putnam (sünd 1941); Kuidas kasvatada sotsiaalset kapitali?

  9. Lahkunud maailmaparandaja Robert Lepikson jäi igavesti otsijaks / Kai Kalamees

    Index Scriptorium Estoniae

    Kalamees, Kai

    2006-01-01

    Ülevaade riigikogu liikme, endise siseministri, Tallinna linnapea ja Võru maavanema Robert Lepiksoni elukäigust, meenutused tuntud ühiskonnategelastelt. Lisad: Robert Lepikson; Kõva sõnaga mees. Vt. samas: Turvavaatleja vastutusrikas töö viimasel rallil; Ivar Raidam: Lepiksoni panus autosporti oli tohutu; Hans H. Luik: Respect, Robert!

  10. Transposition anti-involution in Clifford algebras and invariance groups of scalar products on spinor spaces

    CERN Document Server

    Ablamowicz, Rafal

    2011-01-01

    We introduce on the abstract level in real Clifford algebras \\cl_{p,q} of a non-degenerate quadratic space (V,Q), where Q has signature \\epsilon=(p,q), a transposition anti-involution \\tp. In a spinor representation, the anti-involution \\tp gives transposition, complex Hermitian conjugation or quaternionic Hermitian conjugation when the spinor space \\check{S} is viewed as a \\cl_{p,q}-left and \\check{K}-right module with \\check{K} isomorphic to R or R^2, C, or, H or H^2. \\tp is a lifting to \\cl_{p,q} of an orthogonal involution \\tve: V \\rightarrow V which depends on the signature of Q. The involution is a symmetric correlatio \\tve: V \\rightarrow V^{*} \\cong V and it allows one to define a reciprocal basis for the dual space (V^{*},Q). The anti-involution \\tp acts as reversion on \\cl_{p,0} and as conjugation on \\cl_{0,q}. Using the concept of a transpose of a linear mapping one can show that if [L_u] is a matrix in the left regular representation of the operator L_u: \\cl_{p,q} \\rightarrow \\cl_{p,q} relative to ...

  11. Clifford algebra-based structure filtering analysis for geophysical vector fields

    Science.gov (United States)

    Yu, Z.; Luo, W.; Yi, L.; Hu, Y.; Yuan, L.

    2013-07-01

    A new Clifford algebra-based vector field filtering method, which combines amplitude similarity and direction difference synchronously, is proposed. Firstly, a modified correlation product is defined by combining the amplitude similarity and direction difference. Then, a structure filtering algorithm is constructed based on the modified correlation product. With custom template and thresholds applied to the modulus and directional fields independently, our approach can reveal not only the modulus similarities but also the classification of the angular distribution. Experiments on exploring the tempo-spatial evolution of the 2002-2003 El Niño from the global wind data field are used to test the algorithm. The results suggest that both the modulus similarity and directional information given by our approach can reveal the different stages and dominate factors of the process of the El Niño evolution. Additional information such as the directional stability of the El Niño can also be extracted. All the above suggest our method can provide a new powerful and applicable tool for geophysical vector field analysis.

  12. Clifford algebra-based structure filtering analysis for geophysical vector fields

    Directory of Open Access Journals (Sweden)

    Z. Yu

    2013-07-01

    Full Text Available A new Clifford algebra-based vector field filtering method, which combines amplitude similarity and direction difference synchronously, is proposed. Firstly, a modified correlation product is defined by combining the amplitude similarity and direction difference. Then, a structure filtering algorithm is constructed based on the modified correlation product. With custom template and thresholds applied to the modulus and directional fields independently, our approach can reveal not only the modulus similarities but also the classification of the angular distribution. Experiments on exploring the tempo-spatial evolution of the 2002–2003 El Niño from the global wind data field are used to test the algorithm. The results suggest that both the modulus similarity and directional information given by our approach can reveal the different stages and dominate factors of the process of the El Niño evolution. Additional information such as the directional stability of the El Niño can also be extracted. All the above suggest our method can provide a new powerful and applicable tool for geophysical vector field analysis.

  13. Using Clifford Algebra to Understand the Nature of Negative Pressure Waves

    Science.gov (United States)

    McClellan, Gene

    2014-03-01

    The geometric algebra of 3-D Euclidean space, a sub-discipline of Clifford algebra, is a useful tool for analyzing wave propagation. We use geometric algebra to explore the concept of negative pressure. In free space a straightforward extension of Maxwell's equations using geometric algebra yields a theory in which classical electromagnetic waves coexist with nonelectromagnetic waves having retrograde momentum. By retrograde momentum we mean waves carrying momentum pointing in the opposite direction of energy flow. If such waves exist, they would have negative pressure. In rebounding from a wall, they would pull rather than push. In this presentation we use standard methods of analyzing energy and momentum conservation and their flow through the surface of an enclosed volume to illustrate the properties of both the electromagnetic and nonelectromagnetic solutions of the extended Maxwell equations. The nonelectromagnetic waves consist of coupled scalar and electric waves and coupled magnetic and pseudoscalar waves. They superimpose linearly with electromagnetic waves. We show that the nonelectromagnetic waves, besides having negative pressure, propagate with the speed of light and do not interact with conserved electric currents. Hence, they have three properties in common with dark energy.

  14. Rank-3 root systems induce root systems of rank 4 via a new Clifford spinor construction

    Science.gov (United States)

    Dechant, Pierre-Philippe

    2015-04-01

    In this paper, we show that via a novel construction every rank-3 root system induces a root system of rank 4. Via the Cartan-Dieudonné theorem, an even number of successive Coxeter reflections yields rotations that in a Clifford algebra framework are described by spinors. In three dimensions these spinors themselves have a natural four-dimensional Euclidean structure, and discrete spinor groups can therefore be interpreted as 4D polytopes. In fact, we show that these polytopes have to be root systems, thereby inducing Coxeter groups of rank 4, and that their automorphism groups include two factors of the respective discrete spinor groups trivially acting on the left and on the right by spinor multiplication. Special cases of this general theorem include the exceptional 4D groups D4, F4 and H4, which therefore opens up a new understanding of applications of these structures in terms of spinorial geometry. In particular, 4D groups are ubiquitous in high energy physics. For the corresponding case in two dimensions, the groups I2(n) are shown to be self-dual, whilst via a similar construction in terms of octonions each rank-3 root system induces a root system in dimension 8; this root system is in fact the direct sum of two copies of the corresponding induced 4D root system.

  15. Antes de los Estudios Culturales. Robert Warshow y la experiencia

    Directory of Open Access Journals (Sweden)

    Antonio Lastra

    2008-01-01

    Full Text Available Este artículo estudia la influencia del concepto de experiencia que desarrolla Robert Warshow. Warshow ha supuesto el contrapunto americano a las teorías desarrolladas por Walter Benjamien en Europa. Si bien ambos insistieron en la pobreza de la experiencia, como resultado de la tecnificación de la sociedad, Warshow supo introducir matizaciones que influyeron en todo el círculo de intelectuales concentrados en Nueva York durante la etapa de consolidación de los Estudios Culturales. This paper studies the influence of the experience concept by Robert Warshow. Warshow is the American counterpoint to theories developed by Walter Benjamin in Europe. Although both insisted in the poverty of experience, as a result of technique, Warshow knew how to introduce nuances that influenced intellectuals in New York as Cultural Studies emerged.

  16. The auriferous placer at Mount Robert, Pietersburg Greenstone belt

    International Nuclear Information System (INIS)

    The Mount Robert gold placer near Potgietersrus occurs in coarse, matrix-supported conglomerates of the Uitkyk Formation within the Pietersburg greenstone belt. Sedimentological and mineralogical investigations indicate that the conglomerates and the ore minerals were derived from a greenstone provenance, and that they were deposited in a braided river environment within a rapidly subsiding trough. Lack of sedimentological concentration of the heavy minerals is considered to be the main reason for the low and erratic gold grades encountered (usually below 1 g/t) and, thus, the failure of all past mining ventures. The mineralogical composition of the Mount Robert ore closely resembles that of the Witwatersrand deposits. However, uraninite is absent, probably as a result of its complete removal by weathering processes. Remaining small uranium concentrations can still be detected within the conglomerates where they occur associated with grains of carbonaceous matter, leucoxene aggregates, and secondary iron-hydroxides. U3O8 values found in the conglomerates are given

  17. Robert Aymar receives one of the highest Finnish distinctions

    CERN Multimedia

    2008-01-01

    On 9 December 2008 Robert Aymar, CERN Director-General, was awarded the decoration of Commander, first class, of the Order of the Lion of Finland by the President of the Republic of Finland. This decoration, one of the highest of Finland, was presented in a ceremony by the Ambassador Hannu Himanen, Permanent Representative of Finland to the UN and other international organisations in Geneva. Robert Aymar was honoured for his service to CERN, the LHC, his role in the cooperation between Finland and CERN, as well as his contribution to science in general. In his speech the ambassador underlined CERN’s efforts in the field of education, mentioning the High school teachers programme.

  18. 78 FR 35773 - Airworthiness Directives; MD Helicopters, Inc. (MDHI), Helicopters

    Science.gov (United States)

    2013-06-14

    ... the MDHI Model MD900 helicopters with certain main rotor blade (MRB) retention bolts (bolts) installed... MD 900 helicopters with a main rotor blade retention bolt (bolt), part number (P/N) 900R3100001-103... exist or develop on other products of the same type design. Related Service Information We have...

  19. MD290: Q4 IP6 Quench Level

    CERN Document Server

    Bednarek, Mateusz Jakub; Lechner, Anton; CERN. Geneva. ATS Department

    2016-01-01

    The detailed program proposed for the LHC Machine Development concerning a quench induced by fast losses on the MQY.4L6 quadrupole is presented. The merit of the MD, the necessary modifications of the machine protection systems are presented together with a preliminary analysis of the MD results.

  20. 77 FR 5201 - Drawbridge Operation Regulation; Bear Creek, Dundalk, MD

    Science.gov (United States)

    2012-02-02

    ... Federal Register (73 FR 3316). Public Meeting We do not now plan to hold a public meeting. But you may... SECURITY Coast Guard 33 CFR Part 117 RIN 1625-AA09 Drawbridge Operation Regulation; Bear Creek, Dundalk, MD... across Bear Creek, mile 3.4, between Dundalk and Sparrows Point, MD. The proposed change will alter...

  1. Single-block collision attack on MD5

    NARCIS (Netherlands)

    Stevens, M.M.J.

    2012-01-01

    In 2010, Tao Xie and Dengguo Feng \\cite{cryptoeprint:2010:643} constructed the first single-block collision for MD5 consisting of two 64-byte messages that have the same MD5 hash. Details of their attack, developed using what they call an evolutionary approach, has not been disclosed ``for security

  2. 76 FR 51887 - Safety Zone; Patuxent River, Patuxent River, MD

    Science.gov (United States)

    2011-08-19

    ...) entitled ``Safety Zone; Patuxent River, Patuxent River, MD'' in the Federal Register (76 FR 36447). We... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Patuxent River, Patuxent River, MD AGENCY... safety zone during the ``NAS Patuxent River Air Expo '11,'' which consists of aerial...

  3. Chosen-Prefix Collisions for MD5 and Applications

    NARCIS (Netherlands)

    Stevens, M.M.J.; Lenstra, A.K.; Weger, B. de

    2012-01-01

    We present a novel, automated way to find differential paths for MD5. Its main application is in the construction of \\emph{chosen-prefix collisions}. We have shown how, at an approximate expected cost of $2^{39}$ calls to the MD5 compression function, for any two chosen message prefixes $P$ and $P'$

  4. Robert K. Crane - Na+-Glucose Cotransporter to Cure?

    OpenAIRE

    KirkLHamilton

    2013-01-01

    Dr. Robert K. Crane made major contributions to our understanding of carbohydrate metabolism and transport of the intestine over a very long and productive career. This Perspective examines, briefly, his early life and academic positions, but more importantly, this Perspective highlights his contributions to the understanding of coupled Na+-glucose absorption by the small intestine. I discuss how his early hypothesis of a ‘cotransport’ of sodium and glucose ushered in and provided the physio...

  5. A Voice of Disturbance - Robert Coover und Mythos

    OpenAIRE

    Bell, Elisabeth Ly

    2010-01-01

    This monograph about Robert Coover demonstrates that myth in his works is played out not in merely in naming, or as theme, or recycling of symbols, but rather that his preoccupation with myth(s) pervades his entire work, and does so on multiple levels. Coover’s undermining of inherited systems and their forms in a counter-production differentiates him from his contemporaries and grants him an exceptional position. Following an introductory determination of Coover’s literary significance,...

  6. Biographical Listening: Intimacy, Madness and the Music of Robert Schumann

    OpenAIRE

    Braunschweig, Michelle Elizabeth Yael

    2013-01-01

    Evaluating music as psychological utterance and biographical confession emerged as a mode of music criticism during the early to mid-nineteenth century. Ever since, critics have characterized Robert Schumann as a composer whose works and life are bound together inextricably. The ramifications of these values in Schumann reception and scholarship form the subject of this dissertation. The origins of this practice can be found in the late eighteenth century, when German writers began describing...

  7. Robert K. Crane—Na+-glucose cotransporter to cure?

    OpenAIRE

    Hamilton, Kirk L.

    2013-01-01

    Dr. Robert K. Crane made major contributions to our understanding of carbohydrate metabolism and transport of the intestine over a very long and productive career. This Perspective examines, briefly, his early life and academic positions, but more importantly, this Perspective highlights his contributions to the understanding of coupled Na+-glucose absorption by the small intestine. I discuss how his early hypothesis of a “cotransport” of sodium and glucose ushered in and provided the physiol...

  8. Who was J. Robert Oppenheimer? Charisma and Complex Organization

    OpenAIRE

    Thorpe, Charles; Shapin, Steven

    2000-01-01

    Charismatic authority flourishes in places where some social scientists evidently do not expect to find it - in late modernity and in highly complex and instrumentally orientated technoscientific organizations. This paper documents and interprets participants' testimony about the workings of wartime Los Alamos in relation to the charisma of its Scientific Director. J. Robert Oppenheimer. We treat charisma as an interactional accomplishment, and examine its role in technoscientific organizatio...

  9. Robert J. Aumann - matemaatikust Nobeli preemia laureaat / Peeter Puusemp

    Index Scriptorium Estoniae

    Puusemp, Peeter

    2006-01-01

    2005. a. Nobeli preemia majanduse alal silmapaistva panuse eest mänguteooria ülesannete lahendamisse saanud Robert J. Aumannist ja D. Saari loetelu matemaatikutest - Nobeli preemia laureaatidest: John Nash'ist, Herbert Hauptman'ist, John Pople'ist, Bertrand Arthur William Russell'ist, Kenneth Joseph Arrow'ist, Gerard Debreu'ist, Leonid Vitaljevitš Kantorovitš'ist, Reinhard Selten'ist, Jan Tinbergen'ist

  10. Robert Ignatius Burns (1921-2008. In memoriam

    Directory of Open Access Journals (Sweden)

    Ma Teresa Ferrer

    2009-01-01

    Full Text Available Father Robert Ignatius Burns, a corresponding member of our History and Archeology Section, died at the Jesuit residence in Los Gatos, California, on the 22nd of November 2008. His work has been extremely important and will continue to be so in the future due to his extraordinary contributions to our knowledge of a crucial period in the consolidation and expansion of the Catalan-Aragonese monarchy.

  11. Zimbabwean Nationalism and the rise of Robert Mugabe.

    OpenAIRE

    Riley, Mark Francis.

    1982-01-01

    This thesis discusses the black nationalist movement in Zimbabwe. The first is a history of the Zimbabwean nationalist movement, including the emergence and evolution of the nationalist organizations and leaders, the guerrilla war, and the diplomatic negotiations that occurred up to the Lancaster House Settlement of 1979. The second portion explains why and how Robert Mugabe and the Zimbabwe African National Union won the 1980 elections. The author compares Mugabe with his two principle oppon...

  12. Perfil académico del profesor Robert A. Mundell

    Directory of Open Access Journals (Sweden)

    Ciencias de Suecia Academia Real de

    1999-12-01

    Full Text Available Robert A. Mundell es Profesor de Economía de la Universidad de Culumbia en Nueva York de 1974. Despues de estudiar en el MIT y en la Escuela de Economía de Londres, recibio su Ph.D en el MIT en 1956. Obtuvo la Beca Postdoctoral en Economía Politica en la Universidad de Chicago en 1956-1957.

  13. DFT-MD simulations of shocked Xenon

    Science.gov (United States)

    Magyar, Rudolph J.; Mattsson, Thomas R.

    2009-03-01

    Xenon is not only a technologically important element used in laser technologies, jet propulsion and dental anesthesia, but it is also arguably the simplest material in which to study the metal-insulator transition at high pressure. Because of its closed shell electronic configuration, Xenon is often assumed to be chemically inert, interacting almost entirely through the van der Waals interaction, and at liquid density, is typically modeled well using Leonard-Jones potentials. However, such modeling has a limited range of validity as Xenon is known to form compounds at normal conditions and likely exhibits considerably more chemistry at higher densities when hybridization of occupied orbitals becomes significant. In this talk, we present DFT-MD simulations of shocked liquid Xenon with the goal of developing an improved equation of state. The relative importance of the van der Waals interaction compared to other Coulomb interactions is considered, and estimates of the relative accuracy of various density functionals are quantified. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  14. EDITORIAL: Roberts Prize for the best paper published in 2011 Roberts Prize for the best paper published in 2011

    Science.gov (United States)

    Cherry, Simon; Ruffle, Jon

    2012-08-01

    The publishers of Physics in Medicine and Biology (PMB), IOP Publishing, in association with the journal owners, the Institute of Physics and Engineering in Medicine (IPEM), jointly award an annual prize for the best paper published in PMB during the previous year. The procedure for deciding the winner is a two-stage process. First, a shortlist of contenders is drawn up based on those papers that had the best referees' quality assessments, with a further quality check and endorsement by the Editorial Board. The papers on the shortlist are then reviewed by a specially convened IPEM committee consisting of members with fellow status. This committee reads the shortlisted papers and selects the winner. We have much pleasure in advising readers that the Roberts Prize for the best paper published in 2011 is awarded to Matthew Hough et al from the University of Florida, the Francis Marion University and the National Cancer Institute, USA for their paper on a comprehensive electron dosimetry model of skeletal tissues in the adult male: An image-based skeletal dosimetry model for the ICRP reference adult male—internal electron sources 2011 Phys. Med. Biol. 56 2309 Matthew Hough1, Perry Johnson1, Didier Rajon2, Derek Jokisch3, Choonsik Lee4 and Wesley Bolch1,5 1Department of Nuclear and Radiological Engineering, University of Florida, Gainesville, FL, USA 2Department of Neurosurgery, University of Florida, Gainesville, FL, USA 3Department of Physics and Astronomy, Francis Marion University, Florence, SC, USA 4Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD, USA 5Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA Bone marrow is one of the more radiosensitive tissues in the human body and is housed within a complex structure of bone. This paper describes a comprehensive model of energy deposition by internal electron or beta particle emitters for the ICRP reference adult male based upon ex vivo CT and microCT images of

  15. An Architecture for the Electronic Church: Oral Roberts University in Tulsa, Oklahoma.

    Science.gov (United States)

    Grubiak, Margaret M

    2016-04-01

    More than a university, Oral Roberts University in Tulsa, Oklahoma, was also the headquarters for evangelist Oral Roberts's electronic church. The electronic church in America, dominated by Christian evangelicals, used technology to spread the Gospel over radio airways and television signals to a dispersed audience. Yet evangelicals like Roberts also constructed ambitious campuses in real space and time. The architecture of Oral Roberts University visualized a modern and "populuxe" image for the electronic church in the 1960s and 1970s. The university's Prayer Tower purposely alluded to the Seattle Space Needle, aligning religion and the Space Age, and the campus's white, gold, and black color palette on late modern buildings created an image of aspirational luxury, conveying Roberts's health and wealth gospel. Oral Roberts University served as a sound stage for Roberts's radio and television shows, a pilgrimage point for his audience, and a university dedicated to training evangelicals in the electronic church. PMID:27237069

  16. An eight-dimensional realization of the Clifford algebra in the five-dimensional Galilean covariant spacetime

    International Nuclear Information System (INIS)

    We give an eight-dimensional realization of the Clifford algebra in the five-dimensional Galilean covariant spacetime by using a dimensional reduction from the (5 + 1) Minkowski spacetime to the (4 + 1) Minkowski spacetime which encompasses the Galilean covariant spacetime. A set of solutions of the Dirac-type equation in the five-dimensional Galilean covariant spacetime is obtained, based on the Pauli representation of 8 x 8 gamma matrices. In order to find an explicit solution, we diagonalize the Klein-Gordon divisor by using the Galilean boost

  17. Quantum gravity, Clifford algebras, fuzzy set theory and the fundamental constants of nature

    International Nuclear Information System (INIS)

    In a recent paper entitled 'Quantum gravity from descriptive set theory', published in Chaos, Solitons and Fractals, we considered following the P-adic quantum theory, the possibility of abandoning the Archimedean axiom and introducing a fundamental physical limitation on the smallest length in quantum spacetime. Proceeding that way we arrived at the conclusion that maximising the Hawking-Bekenstein informational content of spacetime makes the existence of a transfinite geometry for physical 'spacetime' plausible or even inevitable. Subsequently we introduced a mathematical description of a transfinite, non-Archimedean geometry using descriptive set theory where a similar conclusion regarding the transfiniteness of quantum spacetime may be drawn from the existence of the Unruh temperature. In particular we introduced a straight forward logarithmic gauge transformation linking, as far as we are aware for the first time, classical gravity with the electroweak via a version of informational entropy. That way we found using ε(∞) and complexity theory that α-barG=(2)α-barew-1=1.7x1038 where α-barG is the dimensionless Newton gravity constant and α-barew=128 is the fine structure constant at the electroweak unification scale. The present work is concerned with more or less the same category of fundamental questions pertinent to quantum gravity. However we switch our mathematical apparatus to a combination of Clifford algebras and set theory. In doing that, the central and vital role of the work of D. Finkelstein becomes much more tangible and clearer than in most of our previous works

  18. Conferencias a la Memoria de la Dra. Lydia J. Roberts 1967, 1969-1973 (Conferences in Memory of Dr. Lydia J. Roberts 1967, 1969-1973).

    Science.gov (United States)

    Puerto Rico Univ., Rio Piedras.

    This publication includes eleven lectures presented as part of a conference given honoring Dr. Lydia J. Roberts. Seven of the papers are written in the English language and four in Spanish. Most of the papers relate to the topic of nutrition, but a few pay tribute to Dr. Roberts in recognition of her distinguished leadership and teacher of human…

  19. The Achromatic Telescopic Squeezing (ATS) MD part III

    CERN Document Server

    Fartoukh, S; Goddard, B; Hofle, W; Jacquet, D; Kruk, G; Lamont, M; de Maria, R; Miyamoto, R; Mueller, G; Pojer, M; Ponce, L; Redaelli, S; Ryckx, N; Steinhagen, R; Strzelczyk, M; Vanbavinckhove, G; Wenninger, J

    2011-01-01

    This note highlights the results obtained during the third so-called ATS MD which took place in 2011. The goal of this MD was extremely challenging, targeting a pre-squeezed beta* of 40 cm in ATLAS and CMS, followed by a telescopic squeeze of these two insertions to finally reach a beta* of 10 cm both at IP1 and IP5. Due to the rather poor machine availability during the MD period, the time initially allocated to the ATS studies was hardly cut by a factor of 2, and "only" the achromatic pre-squeeze down to beta*=40 cm was demonstrated with beam.

  20. Single-block collision attack on MD5

    OpenAIRE

    Stevens, Marc

    2012-01-01

    In 2010, Tao Xie and Dengguo Feng \\cite{cryptoeprint:2010:643} constructed the first single-block collision for MD5 consisting of two 64-byte messages that have the same MD5 hash. Details of their attack, developed using what they call an evolutionary approach, has not been disclosed ``for security reasons''. Instead they have posted a challenge to the cryptology community to find a new different single-block collision attack for MD5. This paper answers that challenge by presenting a single-b...

  1. MD 239 on Collide and Squeeze (part 2)

    CERN Document Server

    Gorzawski, Arkadiusz; Salvachua Ferrando, Belen Maria; Wenninger, Jorg; CERN. Geneva. ATS Department

    2016-01-01

    Colliding the beams during the squeeze to profit from Landau damping due to head--on beam-beam and beta--star leveling are two operational modes that may have to be used in a not so distant future at the LHC. This MD aimed at improving the orbit control during the squeeze with much improved handling of orbit feedback references and at evaluating instruments and techniques to maintain the beam in collisions with active feedback on luminosity or beam position. This MD also integrated for the first time synchronized collimator measurements. Comparison of the settings with the previous MD allowed a validation of the long term stability of collide and squeeze.

  2. Charge separation reaction in clusters of polar molecules. MD simulations

    International Nuclear Information System (INIS)

    Rate constant of intermolecular electron transfer (ET) in a photoexcited donor-acceptor model system solvated by a cluster of polar molecules has been expressed in terms of the statistical distribution of the electrostatic potential energy difference between the reacting sites. This distribution has been calculated for a particular case of acetonitrile clusters at ∼ 120 K by MD computer simulation. The MD values of the cluster reorganization energy and the ET rate constant have been compared with the corresponding MD results for the donor-acceptor pair solvated in bulk acetonitrile and with theoretical predictions based on the continuum model. (author)

  3. MD5Hash加密算法在SQL Server2005中的应用%Application of MD5 Hash Encryption Algorithm in SQL Server 2005

    Institute of Scientific and Technical Information of China (English)

    李红日

    2011-01-01

    在对MD5算法进行简要描述的同时,对MD5算法的原理作深入分析.介绍在C创建MD5 Hash算法的函数,在SQL Server中应用MD5哈希算法,并且经过测试可以准确实现MD5 Hash加密算法.

  4. Cryptanalysis of the Hash Function MD5%关于Hash函数MD5的解析

    Institute of Scientific and Technical Information of China (English)

    毛明; 陈少晖; 袁征; 贾永兴

    2009-01-01

    This paper is about the cryptanalysis of the Hash function MDS, on the basis of the paper concerning the breaking the MD5 which was written by Wang et al.In this paper,the eighth step of MD5 algorithm was taken for exam-ple and the properties of the F function and the effective control of the differential path were introduced.The MD5 algo-rithm was cryptanalyzed from both the manual calculation and the testing program and some part of the paper written by Wang was amended.Finally, the conditions and key points of meeting the differential characteristics were discussed.In general, this paper plays an important role in eryptanalyzing and breaking the MD5 algorithm.%在王小云写的关于分析MD5算法文章的基础上,对MD5算法的破译进行进一步的解析.以MD5算法第八步为例,介绍了F函数的性质和差分路径的有效控制.从手工推算和程序实现两方面时MD5算法进行了解析和测试,对王的文章进行了部分修正,进一步说明了满足差分特征的条件和关键点.这对MD5和其他Hash函数的分析破译有着重要的作用.

  5. Johnson-Kendall-Roberts theory applied to living cells

    CERN Document Server

    Chu, Y S; Thiery, J P; Pérez, E; Pincet, F; Chu, Yeh-Shiu; Dufour, Sylvie; Thiery, Jean Paul; Perez, Eric; Pincet, Frédéric

    2005-01-01

    Johnson-Kendall-Roberts (JKR) theory is an accurate model for strong adhesion energies of soft slightly deformable material. Little is known about the validity of this theory on complex systems such as living cells. We have addressed this problem using a depletion controlled cell adhesion and measured the force necessary to separate the cells with a micropipette technique. We show that the cytoskeleton can provide the cells with a 3D structure that is sufficiently elastic and has a sufficiently low deformability for JKR theory to be valid. When the cytoskeleton is disrupted, JKR theory is no longer applicable.

  6. An Archetypal Study of Plant Imagery in Robert Frost's Poems

    Institute of Scientific and Technical Information of China (English)

    邱芬芬

    2016-01-01

    As one of the most popular American poets in the twentieth century, Robert Frost demonstrated myriads of universally acknowledged works to the world. This paper aims to analyze the plant imagery appearing in his poems from the perspective of archetypal theory. This study, on the basis of analyzing poetic texts, utilizes content analysis to classify plant images into four types and work out relevant statistics. After data analysis based on thematology and archetypal theory, the study finds that plant images in his poems demonstrate the relationship between human beings and nature, psychological conflicts of the poet, death and dismay, expectation for life and rebirth.

  7. Robert Graves y Mallorca: su narrativa breve mallorquina

    OpenAIRE

    Segui Aznar, Juana Mª

    2005-01-01

    Aquest treball d'investigació explora i analitza divuit narracions curtes de Robert Graves publicades al llarg dels anys 1947 a 1962. Està dirigit a establir la relació entre Graves i Mallorca mitjançant els elements autobiogràfics i locals que es poden trobar en les narracions. La idiosincràsia de l'illa queda reflectida en la descripció i comportament dels personatges, en els aspectes socials, polítics, culturals i lingüístics, i en l'escenari espaciotemporal d'aquestes narracions; tots aqu...

  8. The Diffident Naturalist Robert Boyle and the Philosophy of Experiment

    CERN Document Server

    Sargent, Rose-Mary

    1995-01-01

    In a provocative reassessment of one of the quintessential figures of early modern science, Rose-Mary Sargent explores Robert Boyle's philosophy of experiment, a central aspect of his life and work that became a model for mid- to late seventeenth-century natural philosophers and for many who followed them. Sargent examines the philosophical, legal, experimental, and religious traditions—among them English common law, alchemy, medicine, and Christianity—that played a part in shaping Boyle's experimental thought and practice. The roots of his philosophy in his early life and education, in his re

  9. On the Study of Richard Tom Robert Identity

    CERN Document Server

    Tsai, Yeong-Shyeong

    2008-01-01

    In order to estimate the average speed of mosquitoes, a simple experiment was designed by Richard (Lu-Hsing Tsai), Tom (Po-Yu Tsai) and Robert (Hung-Ming Tsai). The result of the experiment was posted in the science exhibitions Taichung Taiwan 1993. The average speed of mosquitoes is inferred by the simple relation is obtained In this paper, we will show how to get the data generated by computer. Though the rigorous proof is not shown, a sketch proof will be shown in this paper

  10. Robert Aymar awarded the Légion d’honneur

    CERN Multimedia

    CERN Bulletin

    2011-01-01

      On 24 May, Robert Aymar, CERN Director-General from 2004 to 2008, was awarded the Légion d’honneur by the French authorities in recognition of his outstanding scientific career. A renowned French physicist, he was Director of the superconducting tokamak Tore Supra from 1977 to 1988, Director of Material Sciences at the CEA in 1990 and Director of the ITER project in 1994. His term of office as CERN Director-General was marked in particular by the commissioning and start-up of the LHC machine, which he inaugurated on 21 October 2008.        

  11. Summary Robert Noyce and the invention of Silicon Valley

    CERN Document Server

    2014-01-01

    This work offers a summary of the book "THE MAN BEHIND THE MICROCHIP: Robert Noyce and the Invention of Silicon Valley""by Leslie Berlin.The Man behind the Microchip is Leslie Berlin's first book. This author is project historian for the Silicon Valley Archives, a division of the Stanford University Department of Special Collections. This book tells the story of a giant of the high-tech industry: the multimillionaire Bob Noyce. This co-founder of Fairchild Semiconductor and Intel co-invented the integrated circuit which became the electronic heart of every modern computer, automobile, advance

  12. Antes de los Estudios Culturales. Robert Warshow y la experiencia

    OpenAIRE

    Antonio Lastra

    2008-01-01

    Este artículo estudia la influencia del concepto de experiencia que desarrolla Robert Warshow. Warshow ha supuesto el contrapunto americano a las teorías desarrolladas por Walter Benjamien en Europa. Si bien ambos insistieron en la pobreza de la experiencia, como resultado de la tecnificación de la sociedad, Warshow supo introducir matizaciones que influyeron en todo el círculo de intelectuales concentrados en Nueva York durante la etapa de consolidación de los Estudios Culturales. This paper...

  13. Waiting time distribution in M/D/1 queueing systems

    DEFF Research Database (Denmark)

    Iversen, Villy Bæk; Staalhagen, Lars

    1999-01-01

    The well-known formula for the waiting time distribution of M/D/1 queueing systems is numerically unsuitable when the load is close to 1.0 and/or the results for a large waiting time are required. An algorithm for any load and waiting time is presented, based on the state probabilities of M/D/1....... The principles are also applicable for other queueing systems...

  14. Autentikasi Pesan Menggunakan Algoritma Message Digest 5 (MD5)

    OpenAIRE

    Simamora, Ali Makmur

    2015-01-01

    When receive or send a message on the network internet, there are some issue which very important namely problem wholeness and authentication. This script discusses about authentication of message with Message Digest algorithm 5. The writter designed an application to ensure the integrity of the message by algorithm MD5. MD5 is a tool to declare the validity of (authentic) sent messages as well as message. To express validity of message in the text or file will used encryption method, so the ...

  15. Clifford Fourier-Mellin transform with two real square roots of -1 in Cl(p,q), p+q=2

    OpenAIRE

    Hitzer, Eckhard

    2013-01-01

    We describe a non-commutative generalization of the complex Fourier-Mellin transform to Clifford algebra valued signal functions over the domain $\\R^{p,q}$ taking values in Cl(p,q), p+q=2. Keywords: algebra, Fourier transforms; Logic, set theory, and algebra, Fourier analysis, Integral transforms

  16. Robert Schumann in the psychiatric hospital at Endenich.

    Science.gov (United States)

    Steinberg, Reinhard

    2015-01-01

    Robert Schumann (1810-1856) spent the last two-and-a-half years of his life in the private psychiatric hospital in Endenich. His medical records emerged in 1991 and were published by B. R. Appel in 2006. Daily entries document the treatment typical at that time for what was at first considered to be "melancholy with delusions": Shielding from stimuli, physical procedures, and a dietary regimen. The feared, actual diagnosis, a "general (incomplete) paralysis," becomes a certainty in the course of the paranoid-hallucinatory symptoms with cerebro-organic characteristics and agitated states, differences in pupil size, and increasing speech disturbances. In the medicine of the time, syphilis is just emerging as the suspected cause, and the term "progressive paralysis" is coined as typical for the course. Proof of the Treponema pallidum infection and the serologic reaction is not obtained until 1906. People close to Robert, in particular his wife Clara and the circle of friends around Brahms and Joachim, cared intensively for him and suffered under the therapeutic isolation. The medical records and illness-related letters contradict the theory that Schumann was disposed of by being put into the psychiatric hospital; they show the concern of all during the unfavorable illness course. PMID:25684293

  17. Research of the Hash Algorithm Based on MD5%MD5散列算法的研究

    Institute of Scientific and Technical Information of China (English)

    姜学军; 曹烨

    2014-01-01

    借鉴了M.M.J.Stevens的碰撞思路,重新编写了MD5碰撞算法中的核心循环,主要提供一对MD5碰撞产生的过程以及碰撞的完成.通过实验统计分析,利用改进的MD5碰撞算法找到一对碰撞信息所用平均时间不多于60s,且该算法较之传统的MD5碰撞算法具有更好的可读性和可移植性.

  18. Cummins MD & HD Accessory Hybridization CRADA -Annual Report FY15

    Energy Technology Data Exchange (ETDEWEB)

    Deter, Dean D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-01

    There are many areas of MD and HD vehicles that can be improved by new technologies and optimized control strategies. Component optimization and idle reduction need to be addressed, this is best done by a two part approach that includes selecting the best component technology, and/or architecture, and optimized controls that are vehicle focused. While this is a common focus in the light duty industry it has been gaining momentum in the MD and HD market as the market gets more competitive and the regulations become more stringent. When looking into systems optimization and idle reduction technologies, affected vehicle systems must first be considered, and if possible included in the new architecture to get the most benefit out of these new capabilities. Typically, when looking into idle reduction or component optimization for MD/HD, the vehicle s accessories become a prime candidate for electrification or hybridization. While this has already been studied on light duty vehicles (especially on hybrids and electric vehicles) it has not made any head way or market penetration in most MD and HD applications. If hybrids and electric MD and HD vehicles begin to break into the market this would be a necessary step into the ability to make those vehicles successful by allowing for independent, optimized operation separate from the engine.

  19. Gravitation and the earth sciences: the contributions of Robert Dicke

    CERN Document Server

    Kragh, Helge

    2015-01-01

    The American physicist Robert Dicke (1916-1997) is primarily known for his important contributions to gravitation, cosmology, and microwave physics. Much less known is his work in geophysics and related areas of the earth sciences in which he engaged himself and several of his collaborators in the period from about 1957 to 1969. Much of Dicke's work in geophysics was motivated by his wish to obtain evidence in support of the non-Einstenian Brans-Dicke theory of gravitation. The idea of a decreasing gravitational constant, as entertained by Dicke and some other physicists (including Pascual Jordan), played some role in the process that transformed the static picture of the Earth to a dynamical picture. It is not by accident that Dicke appears as a minor actor in histories of the plate tectonic revolution in the 1960s.

  20. Robert K. Crane - Na+-Glucose Cotransporter to Cure?

    Directory of Open Access Journals (Sweden)

    KirkLHamilton

    2013-03-01

    Full Text Available Dr. Robert K. Crane made major contributions to our understanding of carbohydrate metabolism and transport of the intestine over a very long and productive career. This Perspective examines, briefly, his early life and academic positions, but more importantly, this Perspective highlights his contributions to the understanding of coupled Na+-glucose absorption by the small intestine. I discuss how his early hypothesis of a ‘cotransport’ of sodium and glucose ushered in and provided the physiological explanation for the clinical treatment of acute diarrhea and cholera when using oral rehydration therapy (ORT. ORT saves millions of lives each year. Certainly, humankind is better off because of Crane’s hypothesis of the Na+-glucose cotransporter which he put forth over 50 years ago?

  1. Robert Schumann and translation: poetic creativity, simultaneity and movement

    Directory of Open Access Journals (Sweden)

    João Azenha Junior

    2012-07-01

    Full Text Available In diesem Aufsatz werden die Gesammelten Schriften über Musik und Musiker von Robert Schumann untersucht, insbesondere die Rezensionen, die der Komponist zwischen 1834 und 1836 verfasst hat. Es soll festgestellt werden, inwiefern sich darin die wichtigsten Auffassungen über Sprache und Übersetzung, die Ende des 18. und Beginn des 19. Jahrhunderts in Deutschland entstanden, wiederfinden. Im Vordergrund der Untersuchung steht die Dimension der Bewegung, die sich sowohl im Individuum als auch in der Zeit festmachen lässt. Im Individuum manifestiert sich die Bewegung als ein sehr persönlicher Vorgang, da es sich innerhalb verschiedener Zeichensysteme bewegt, die seine Gedanken ausdrücken; oder aber es bewegt sich innerhalb verschiedener Sprachen. Die Zeitdimension wiederum bedeutet, in ein Umfeld einzutauchen, das die Zeitbarrieren überwindet und die Vergangenheit auf einen Schlag mit der Gegenwart und der Zukunft verbindet.

  2. Accuracy evaluation of pendulum gravity measurements of Robert von Sterneck

    Directory of Open Access Journals (Sweden)

    Alena Pešková

    2015-06-01

    Full Text Available The accuracy of first pendulum gravity measurements in the Czech territory was determined using both original surveying notebooks of Robert Daublebsky von Sterneck and modern technologies. Since more accurate methods are used for gravity measurements nowadays, our work is mostly important from the historical point of view. In previous  works, the accuracy of Sterneck’s gravity measurements was determined using only a small dataset. Here we process all Sterneck’s measurements from the Czech territory (a dataset ten times larger than in the previous works, and we complexly assess the accuracy of these measurements. Locations of the measurements were found with the help of original notebooks. Gravity in the site was interpolated using actual gravity models. Finally, the accuracy of Sterneck’s measurements was evaluated as the difference between the measured and interpolated gravity.

  3. Hooke's figurations: a figural drawing attributed to Robert Hooke.

    Science.gov (United States)

    Hunter, Matthew C

    2010-09-20

    The experimental philosopher Robert Hooke (1635-1703) is known to have apprenticed to the leading painter Peter Lely on his first arrival in London in the late 1640s. Yet the relevance of Hooke's artistic training to his mature draughtsmanship and identity has remained unclear. Shedding light on that larger interpretive problem, this article argues for the attribution to Hooke of a figural drawing now in Tate Britain (T10678). This attributed drawing is especially interesting because it depicts human subjects and bears Hooke's name functioning as an artistic signature, both highly unusual features for his draughtsmanship. From evidence of how this drawing was collected and physically placed alongside images by leading artists in the early eighteenth century, I suggest how it can offer new insight into the reception of Hooke and his graphic work in the early Enlightenment. PMID:20973449

  4. Robert Koch redux: malaria immunology in Papua New Guinea.

    Science.gov (United States)

    Stanisic, D I; Mueller, I; Betuela, I; Siba, P; Schofield, L

    2010-08-01

    Over a century ago, the malaria expedition of the brilliant microbiologist Robert Koch to the Dutch East Indies (Indonesia) and German New Guinea (now Papua New Guinea, or PNG), resulted in profound observations that are still central to our current understanding of the epidemiology and acquisition of immunity to the malaria parasite Plasmodium. The tradition of malaria research in PNG pioneered by Koch continues to this day, with a number of recent studies still continuing to elucidate his original concepts and hypotheses. These include age and exposure-related acquisition of immunity, species-specific and cross-species immunity, correlates of protective immunity and determining the prospects for anti-malaria vaccines. PMID:20626817

  5. Robert Hooke: early respiratory physiologist, polymath, and mechanical genius.

    Science.gov (United States)

    West, John B

    2014-07-01

    Robert Hooke (1635-1703) was a polymath who made important contributions to respiratory physiology and many other scientific areas. With Robert Boyle, he constructed the first air pump that allowed measurements on small animals at a reduced atmospheric pressure, and this started the discipline of high-altitude physiology. He also built the first human low-pressure chamber and described his experiences when the pressure was reduced to the equivalent of an altitude of ∼2,400 m. Using artificial ventilation in an animal preparation, he demonstrated that movement of the lung was not essential for life. His book Micrographia describing early studies with a microscope remains a classic. He produced an exquisite drawing of the head of a fly, showing the elaborate compound eye. There is also a detailed drawing of a flea, and Hooke noted how the long, many-jointed legs enable the insect to jump so high. For 40 years, he was the curator of experiments for the newly founded Royal Society in London and contributed greatly to its intellectual ferment. His mechanical inventions covered an enormous range, including the watch spring, the wheel barometer, and the universal joint. Following the Great Fire of London in 1666, he designed many of the new buildings in conjunction with Christopher Wren. Unfortunately, Hooke had an abrasive personality, which was partly responsible for a lack of recognition of his work for many years. However, during the last 25 years, there has been renewed interest, and he is now recognized as a brilliant scientist and innovator. PMID:24985326

  6. Robert Musil y los Estados desunificados de Europa

    Directory of Open Access Journals (Sweden)

    Bayón, Fernando

    2006-12-01

    Full Text Available This article is a study of Robert Musil´s work “The Man Without Qualities” from philosophical sources. It is a novel that has produced so many overriding metaphors through which we can better understand the crises of the social identity on the horizont of the last modernity in Europe. Much of the key-concepts that helped in creating the so called “Leyend of Modernity” start to vanish in an irremediable way: not only did Musil trace the disappearance of the support for national aspirations and social cohesion, he also showed us how culture is a mad carrousel of collapsed expectations, and how the prevailing idea of “subjectivity” lacks today any solid or essential nucleus. In the middle of this disenchanted landscape of Europe, where all the modern and clasical illusions became nothing, appears however “a new human being”, since the man “without qualities” is the man with endless possibilities too.El presente ensayo es una interpretación de la novela de Robert Musil “El hombre sin atributos” a partir de fuentes filosóficas. Se trata de una obra que ha producido algunas metáforas decisivas para comprender las crisis de la identidad social en el horizonte de la última modernidad europea. Muchos de los conceptos clave que ayudaron a crear la leyenda de la modernidad empiezan a erosionarse de modo irreversible: se descomponen las aspiraciones nacionales, el sujeto pierde su núcleo sustancial y la cultura es un carrusel de esperanzas abortadas incapaces de responder a ninguna idea rectora. Y, sin embargo, en el paisaje de esta Europa tardomoderna en que se han agotado las pasadas ilusiones surge la idea de que el “hombre sin atributos” es también el “hombre de las posibilidades”.

  7. Age Changes in Personality and Their Origins: Comment on Roberts, Walton, and Viechtbauer (2006)

    Science.gov (United States)

    Costa, Paul T.; McCrae, Robert R.

    2006-01-01

    This article presents comments on the original article "Patterns of Mean-Level Change in Personality Traits Across the Life Course: A Meta-Analysis of Longitudinal Studies," by B. W. Roberts, K. W. Walton, and W. Viechtbauer. Although Roberts et al depicted the present authors as proponents of the immutability of traits, in fact we have always…

  8. 77 FR 48533 - Notice of Inventory Completion: The Robert S. Peabody Museum of Archaeology, Phillips Academy...

    Science.gov (United States)

    2012-08-14

    ... National Park Service Notice of Inventory Completion: The Robert S. Peabody Museum of Archaeology, Phillips.... Peabody Museum of Archaeology has completed an inventory of human remains, in consultation with the... culturally affiliated with the human remains may contact the Robert S. Peabody Museum of...

  9. Duchon-Robert solutions for the Rayleigh-Taylor and Muskat problems

    OpenAIRE

    Beck, Thomas; Sosoe, Philippe; Wong, Percy

    2012-01-01

    We construct analytic solutions to the Euler equations with an interface between two fluids, extending work of Duchon and Robert. We also show that the estimates of Duchon and Robert yield global analytic solutions to the Muskat problem with small initial data.

  10. Differential operators in a Clifford analysis associated to differential equations with anti-monogenic right-hand sides

    International Nuclear Information System (INIS)

    This paper deals with the initial value problem of the type φw / φt = L (t, x, w, φw / φxi) (1) w(0, x) = φ(x) (2) where t is the time, L is a linear first order operator in a Clifford Analysis and φ is a generalized monogenic function. We give sufficient conditions on the coefficients of operator L under which L is associated to differential equations with anti-monogenic right-hand sides. For such operator L the initial problem (1),(2) is solvable for an arbitrary generalized monogenic initial function φ and the solution is also generalized monogenic for each t. (author)

  11. Clifford Algebra Derivations of Tau-Functions for Two-Dimensional Integrable Models with Positive and Negative Flows

    Directory of Open Access Journals (Sweden)

    Henrik Aratyn

    2007-02-01

    Full Text Available We use a Grassmannian framework to define multi-component tau functions as expectation values of certain multi-component Fermi operators satisfying simple bilinear commutation relations on Clifford algebra. The tau functions contain both positive and negative flows and are shown to satisfy the $2n$-component KP hierarchy. The hierarchy equations can be formulated in terms of pseudo-differential equations for $nimes n$ matrix wave functions derived in terms of tau functions. These equations are cast in form of Sato-Wilson relations. A reduction process leads to the AKNS, two-component Camassa-Holm and Cecotti-Vafa models and the formalism provides simple formulas for their solutions.

  12. A wave equation including leptons and quarks for the standard model of quantum physics in Clifford Algebra

    CERN Document Server

    Daviau, Claude

    2014-01-01

    A wave equation with mass term is studied for all particles and antiparticles of the first generation: electron and its neutrino, positron and antineutrino, quarks $u$ and $d$ with three states of color and antiquarks $\\overline{u}$ and $\\overline{d}$. This wave equation is form invariant under the $Cl_3^*$ group generalizing the relativistic invariance. It is gauge invariant under the $U(1)\\times SU(2) \\times SU(3)$ group of the standard model of quantum physics. The wave is a function of space and time with value in the Clifford algebra $Cl_{1,5}$. All features of the standard model, charge conjugation, color, left waves, Lagrangian formalism, are linked to the geometry of this extended space-time.

  13. A Wave Equation including Leptons and Quarks for the Standard Model of Quantum Physics in Clifford Algebra

    Science.gov (United States)

    Daviau, Claude; Bertrand, Jacques

    A wave equation with mass term is studied for all particles and antiparticles of the first generation: electron and its neutrino, positron and antineutrino, quarks $u$ and $d$ with three states of color and antiquarks $\\overline{u}$ and $\\overline{d}$. This wave equation is form invariant under the $Cl_3^*$ group generalizing the relativistic invariance. It is gauge invariant under the $U(1)\\times SU(2) \\times SU(3)$ group of the standard model of quantum physics. The wave is a function of space and time with value in the Clifford algebra $Cl_{1,5}$. All features of the standard model, charge conjugation, color, left waves, Lagrangian formalism, are linked to the geometry of this extended space-time.

  14. 基于C#的MD5加密算法的应用%Application of the MD5 algorithm based on C#

    Institute of Scientific and Technical Information of China (English)

    林宗朝

    2011-01-01

    介绍了WEB SYSTEM中的密钥安全性能。主要讨论了WEB SYSTEM中MD5加密算法,包含客户password安全性分析、MD5加密算法概述、基于C#的MD5加密应用介绍,以及IT SYSTEM中MD5算法的应用与IMPROVEMENT等问题。%The key safety properties of the WEB system is described,and the.MD5 encryption algorithm is discussed mainly including the user password security analysis,MD5 encryption algorithm summary,MD5 encryption applications based on the C# and the improvement of MD5 algorithm.

  15. BI MD Studies on June 29th 2011

    CERN Document Server

    Belohrad, D; Bravin, E; Calvo, E; Dehning, B; Emery, J; Favier, M; Gras, JJ; Guerrero, A; Jeff, A; Lefevre, T; Rabiller, A; Roncarolo, F; Sapinski, M; Soby, L; Steinhagen, R

    2011-01-01

    This note contains the preliminary results of the LHC MD that took place on 29-June-2011 (from 10 p.m. to 07 a.m.), dedicated to study Beam Current Monitors (BCT), Wire Scaners (WS), Synchrotron Radiation (BSRT), Beam Position (BPM), Wall Current (WCM) and Beam Gas Ionization (BGI) monitors. The MD aimed at performing different studies on the individual monitors. At the same time, it was possible to perform calibration studies with the Abort Gap (AGM) and Longitudinal Density (LDM) monitors that share the extracted light with the BSRT. Additionally some observations about the beam stability and emittance dependence on the chromaticity were performed.

  16. Charles Robert Darwin and Argentina's National Academy of Sciences Charles Robert Darwin y la Academia Nacional de Ciencias

    Directory of Open Access Journals (Sweden)

    Pedro José Depetris

    2009-04-01

    Full Text Available Over 175 years ago Charles Robert Darwin arrived in Argentina to find a bare and boundless plain, the brave centaur called "gaucho", Quaternary fossils everywhere, and a society strikingly strange and aggressive to the British eyes of the young traveller. Although the voyage aboard HMS Beagle was the indispensable way towards increasing his stature as a biologist, Lyell's work awakened an inquisitive geological mind which allowed him to wonder at the splendour of the Andes. Forty-two years after having concluded his voyage on the Beagle, the National Academy of Sciences of Argentina appointed him as an Honorary Member. This must be interpreted as an early gesture of recognition -in the context of those times- to the magnificence of his scientific work.Hace más de 175 años, Charles Robert Darwin llegaba a la Argentina para descubrir una llanura desprovista de límites y de árboles, el valeroso centauro que era el gaucho, fósiles cuaternarios por doquier y una sociedad sorprendentemente extraña y agresiva a los británicos ojos del joven viajero. Aunque el viaje a bordo del Beagle fue el camino indispensable para incrementar su estatura como biólogo, la obra de Lyell despertó una mente inquisitivamente geológica que le permitió maravillarse ante la magnificencia de los Andes. Cuarenta y dos años después de haber concluido su viaje en el Beagle, la Academia Nacional de Ciencias de Argentina lo designó Miembro Honorario, en lo que debe interpretarse como un temprano gesto de reconocimiento -en el contexto del momento- por la magnificencia de su obra científica.

  17. Analysis of the message digest algorithm MD5%报文摘要算法MD5分析

    Institute of Scientific and Technical Information of China (English)

    燕辉; 叶震; 董泽浩; 高柯俊

    2002-01-01

    随着计算机网络的发展,社会对网络安全的要求也越来越紧迫。文章回顾了网络安全的目标、几种网络攻击方法和网络安全技术,重点分析了普遍用在数据签名中的MD5报文摘要算法。首先描述了MD5报文摘要算法,并对其进行了详细分析,找出了它的缺陷,最后推荐了一种为克服此缺陷而对MD5算法进行的改进方法。

  18. Hardware Implementation of HMAC-MD5 Algorithm%HMAC-MD5算法的硬件实现

    Institute of Scientific and Technical Information of China (English)

    吴旭凡; 胡晨; 田渊; 丁黄胜

    2003-01-01

    信息安全体系中的消息验证是一个非常重要的方面.采用以散列函数为基础的消息验证编码是其中的一种重要方法.现提出了硬件实现一种以MD5算法为基础的消息验证编码(HMAC-MD5)的电路结构.该电路结构通过对MD5核心运算模块的复用,缩小了电路规模,达到了较高的处理速度.用VerilogHDL描述电路结构,并且在FPGA上验证了该结构的正确性.

  19. Research and Improvement of MD5 Algorithm%MD5算法的研究与改进

    Institute of Scientific and Technical Information of China (English)

    毛熠; 陈娜

    2012-01-01

    MD5 algorithm has important applications in the field of data encryption such as digital signature, identity authentication and so on, but it can not resist differential attack and dictionary attack. This paper does certain special transform on some related variables during message preprocessing course of MD5 to improve probability of data high overflow, and increase the avalanche effect and difficulty of differential cryptanalysis, so that collision problem of MD5 algorithm is solved. Through doing collision detection, coincidence detection of encrypted values before and after improvement for improved algorithm, the improved MD5 is proved safe and practical.%MD5算法在数字签名、身份认证等数据加密领域有重要的应用,但其无法抵御差分攻击和查字典攻击.为此,通过对算法消息处理过程中涉及的一些变量进行特殊变换,提高运算中数据高位溢出的几率,增强其雪崩效应,增加差分分析的难度,由此解决MD5算法的碰撞问题.对改进的算法进行碰撞检测、加密值重合检测以及改进前后加密值的重合检测,结果证明其具有较高的安全性和实用价值.

  20. Research of MD5 shadow table method based on MD5 algorithm%一种融入MD5的影子表算法研究

    Institute of Scientific and Technical Information of China (English)

    袁满; 康峰峰; 黄刚

    2013-01-01

    As for the rapid extraction of source data, the rapid identification of changing data and the rapid incremental extraction of data, underlying the analysis of the working principle of the traditional shadow table, this paper proposed a kind of improved linear algorithm which merged MD5 algorithm into the ST. It scanned compared tables for the linear and eliminates unnecessary inverse operation. During scanning these tables, it employed MD5 algorithm to calculate the whole record ' fingerprint ' , it reduced the frequency and duration of string matching, and it could quickly recognize the changed records. The algorithm was verified practically, and the result shows that the proposed algorithm can improve the efficiency of data extraction in database. Incremental extraction method based on shadow table is a general incremental capturing method, and it can be implemented in any database. These applications can easily be transplanted in all kinds of platforms, so it is suitable to solve the heterogeneous database replication issues.%为了快速提取源头数据、快速识别变化记录以及实现数据的快速增量提取,在剖析传统影子表法的工作原理上,提出基于MD5算法的影子表法的改进型线性算法,对对比表进行线性扫描,排除了不必要的回扫操作;同时通过MD5算法计算整条记录的“指纹”,降低了字符串比对次数和时间,能够迅速识别出发生变化的记录.对所提出算法进行了应用测试,结果表明通过融入MD5算法后的影子表法提高了数据提取效率.基于影子表的增量提取方法是一种通用的增量捕获方法,能在任何数据库上实现;应用程序可以方便地在多种平台间移植,因此很适合解决异构数据库复制问题.

  1. 78 FR 3496 - Maryland Disaster Number MD-00025

    Science.gov (United States)

    2013-01-16

    ... ADMINISTRATION Maryland Disaster Number MD-00025 AGENCY: U.S. Small Business Administration. ACTION: Amendment 3... completed loan applications to: U.S. Small Business Administration, Processing and Disbursement Center... Disaster Assistance, U.S. Small Business Administration, 409 3rd Street SW., Suite 6050, Washington,...

  2. 77 FR 74908 - Maryland Disaster Number MD-00025

    Science.gov (United States)

    2012-12-18

    ... ADMINISTRATION Maryland Disaster Number MD-00025 AGENCY: U.S. Small Business Administration. ACTION: Amendment 1... completed loan applications to: U.S. Small Business Administration, Processing and Disbursement Center... Disaster Assistance, U.S. Small Business Administration, 409 3rd Street SW., Suite 6050, Washington,...

  3. Improved Collision Attack on Hash Function MD5

    Institute of Scientific and Technical Information of China (English)

    Jie Liang; Xue-Jia Lai

    2007-01-01

    In this paper, we present a fast attack algorithm to find two-block collision of hash function MD5.The algorithm is based on the two-block collision differential path of MD5 that was presented by Wang et al.In the Conference EUROCRYPT 2005.We found that the derived conditions for the desired collision differential path were not sufficient to guarantee the path to hold and that some conditions could be modified to enlarge the collision set.By using technique of small range searching and omitting the computing steps to check the characteristics in the attack algorithm, we can speed up the attack of MD5 efficiently.Compared with the Advanced Message Modification technique presented by Wang et al.,the small range searching technique can correct 4 more conditions for the first iteration differential and 3 more conditions for the second iteration differential, thus improving the probability and the complexity to find collisions.The whole attack on the MD5 can be accomplished within 5 hours using a PC with Pentium4 1.70GHz CPU.

  4. MD on Injection Quality – Longitudinal and Transverse Parameters

    CERN Document Server

    Drosdal, L; Bohl, T; Bracco, C; Cornelis, K; Damerau, H; Goddard, B; Kain, V; Meddahi, M

    2011-01-01

    Losses at injection depend on the beam quality in the longitudinal and transverse plane in the injectors. During the MD on the 30th of June to 1st of July, 2011, many parameters in the injectors were de-tuned on purpose to see the effect on injection losses and hence bring some understanding to recurring problems with injection quality during LHC filling. The effect of the 800 MHz in the SPS, radial steering, larger momentum spread at the SPS extraction and many other longitudinal parameters were studied during the MD. The MD showed however that the injection losses are dominated by far by the transverse size of the particle population. If the SPS scrapers are correctly positioned, injection losses are low even at the presence of quality issues in the longitudinal plane. To be able to inject brighter 50 ns beams or eventually 25 ns beams, injection losses with nominal emittances (3.5 m) must still be acceptable. This MD showed that nominal emittances can be injected with similar loss levels as the typical ...

  5. 76 FR 36447 - Safety Zone; Patuxent River, Patuxent River, MD

    Science.gov (United States)

    2011-06-22

    ..., 2008, issue of the Federal Register (73 FR 3316). Public meeting We do not now plan to hold a public... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Patuxent River, Patuxent River, MD AGENCY... a temporary safety zone during the ``NAS Patuxent River Air Expo '11'', which consists of...

  6. Developing improved MD codes for understanding processive cellulases

    International Nuclear Information System (INIS)

    The mechanism of action of cellulose-degrading enzymes is illuminated through a multidisciplinary collaboration that uses molecular dynamics (MD) simulations and expands the capabilities of MD codes to allow simulations of enzymes and substrates on petascale computational facilities. There is a class of glycoside hydrolase enzymes called cellulases that are thought to decrystallize and processively depolymerize cellulose using biochemical processes that are largely not understood. Understanding the mechanisms involved and improving the efficiency of this hydrolysis process through computational models and protein engineering presents a compelling grand challenge. A detailed understanding of cellulose structure, dynamics and enzyme function at the molecular level is required to direct protein engineers to the right modifications or to understand if natural thermodynamic or kinetic limits are in play. Much can be learned about processivity by conducting carefully designed molecular dynamics (MD) simulations of the binding and catalytic domains of cellulases with various substrate configurations, solvation models and thermodynamic protocols. Most of these numerical experiments, however, will require significant modification of existing code and algorithms in order to efficiently use current (terascale) and future (petascale) hardware to the degree of parallelism necessary to simulate a system of the size proposed here. This work will develop MD codes that can efficiently use terascale and petascale systems, not just for simple classical MD simulations, but also for more advanced methods, including umbrella sampling with complex restraints and reaction coordinates, transition path sampling, steered molecular dynamics, and quantum mechanical/molecular mechanical simulations of systems the size of cellulose degrading enzymes acting on cellulose

  7. Developmentally regulated expression of two MADS-box genes, MdMADS3 and MdMADS4, in the morphogenesis of flower buds and fruits in apple.

    Science.gov (United States)

    Sung, S K; Yu, G H; Nam, J; Jeong, D H; An, G

    2000-03-01

    Two MADS-box genes, MdMADS3 and MdMADS4, were isolated from the apple (Malus x domestica Borkh.) cultivar Fuji, and their spatial and temporal expression patterns were studied during morphological differentiation of the flower buds and the fruits. Both MdMADS3 and MdMADS4 showed high sequence similarities to FBP2 from petunia, TM5 from tomato, and AGL2, AGL4 from Arabidopsis. Although MdMADS3 was expressed in the inner three whorls of the floral primordium, its expression was hardly detectable in developing fruit. The second gene, MdMADS4, was ubiquitously expressed in the inflorescence meristem, floral meristem, all four floral organs, and fruit. Moreover, MdMADS4 expression was high in the vascular bundles assigned to the floral tube and the carpellary vascular bundles in fruit at early developmental stages. The MdMADS4 transcript also accumulated in embryos of the developing seeds. These results suggest that MdMADS3 and MdMADS4 are involved in different functions, and that MdMADS4 may function in the important events controlling flower and fruit development. PMID:10787044

  8. Two-dimensional gravity as the gauge theory of the Clifford algebra for an even-dimensional generalized Chern-Simons action

    International Nuclear Information System (INIS)

    We investigate the two-dimensional version of the Chern-Simons action derived from the recently proposed even-dimensional generalized Chern-Simons action. We show that the two-dimensional topological gravity emerges if we choose the Clifford algebra as a nonstandard gauge symmetry algebra required from the generalized Chern-Simons action. We find a ''hidden order parameter'' which differentiates the gravity phase and nongravity phase

  9. 基于MD5的迭代散列算法%Iterative Hashing Algorithm Based on MD5

    Institute of Scientific and Technical Information of China (English)

    张青

    2011-01-01

    The paper analyzes the user name and password storage methods and their risks on the internet. On this basis, it analyzes MD5 message digest encryption weaknesses and deciphering means. In response to these decoding methods, it proposes an iterative algorithm based on MD5. This algorithm is immune to the second birthday attack, meanwhile improve the complicates of the the first birthday attack. It is also useful for rainbow table attack. The algorithm can enhance password security features, thereby enhancing the network information transmission and storage security.%分析网络中用户名、密码的存储方式及其存在的风险.在此基础上分析MD5散列算法的弱点及其破译手段.针对这些破泽方法提出基于MD5的迭代散列算法.该算法可以避免第二类生日攻击,并有效提高第一类生日攻击的复杂度,对于破解效率最高的彩虹表也具有免疫性,能够加强密码的安全性能,从而提高网络中信息传递和存储的安全性.

  10. Trinity, time and ecumenism in Robert Jenson’s theology

    Directory of Open Access Journals (Sweden)

    Anné H. Verhoef

    2011-09-01

    Full Text Available Robert Jenson, an American Lutheran theologian, is well known as a Trinitarian and
    ecumenical theologian. In his Trinitarian theology he makes specific choices regarding
    the relationship between God and time as an attempt to overcome the Hellenistic
    influences on the early church’s theology, especially about the timelessness of God.
    Jenson proposes a temporal infinity or timefullness of God, which is central to the
    relationships within the Trinity. Jenson temporally defines the unity of the Trinity
    in relation to the claim that God is in fact the mutual life and action of the three
    persons, Father, Son and Spirit as they move toward the future. In the Trinity’s
    relationship to time the person Jesus fulfils a very specific role, namely the “specious
    present”, and this temporal location of Him leads in Jenson’s theology to a very
    strong ecclesiology and eventually to specific proposals regarding ecumenism. In this
    article I will investigate this link between Trinity, time and ecumenism in Jenson’s
    theology.

  11. Composition and adaptation in the life of Robert Schumann.

    Science.gov (United States)

    Graves, John S

    2005-01-01

    The composer Robert Schumann, who suffered from bipolar disorder, utilized his impressive musical and literary talents in attempts to adapt to multiple developmental traumas, separations, and losses as well as to the ongoing ravages of his mood disorder. By analyzing several of his Lieder, the author formulates and describes several defense mechanisms involved in these adaptations. These include identification with the lost object, the use of transitional objects and phenomena, sublimation, denial, minimization, idealization, playfulness, and the employment of healthy obsessive traits. Schumann utilized these adaptive defenses successfully for a brief period, thus coping with a difficult separation from his fiancée, Clara. Ultimately, however, he was unable to experience mature mourning regarding the deaths of several family members. The author, drawing on his extensive experience with treating bipolar individuals in outpatient settings, discusses some of the difficulties that many bipolar patients like Schumann have with mourning, including early developmental vulnerabilities to separation and loss, the disorganizing effects of bipolar mood episodes on cognition and self-coherence, the need to camouflage affects reminiscent of bipolar mood episodes, and experiencing these affects and mood episodes as traumatic reoccurrences. By studying the biographies of creative individuals such as Schumann, clinicians can expand their appreciation of their patients' adaptive capacities and thus assist them in restoring a sense of hope and vitality in their lives. PMID:16370792

  12. Statistical ultrasonics: the influence of Robert F. Wagner

    Science.gov (United States)

    Insana, Michael F.

    2009-02-01

    An important ongoing question for higher education is how to successfully mentor the next generation of scientists and engineers. It has been my privilege to have been mentored by one of the best, Dr Robert F. Wagner and his colleagues at the CDRH/FDA during the mid 1980s. Bob introduced many of us in medical ultrasonics to statistical imaging techniques. These ideas continue to broadly influence studies on adaptive aperture management (beamforming, speckle suppression, compounding), tissue characterization (texture features, Rayleigh/Rician statistics, scatterer size and number density estimators), and fundamental questions about how limitations of the human eye-brain system for extracting information from textured images can motivate image processing. He adapted the classical techniques of signal detection theory to coherent imaging systems that, for the first time in ultrasonics, related common engineering metrics for image quality to task-based clinical performance. This talk summarizes my wonderfully-exciting three years with Bob as I watched him explore topics in statistical image analysis that formed a rational basis for many of the signal processing techniques used in commercial systems today. It is a story of an exciting time in medical ultrasonics, and of how a sparkling personality guided and motivated the development of junior scientists who flocked around him in admiration and amazement.

  13. Anthony (Tony) ROBERTS 5 March 1948 – 16 January 2008

    CERN Multimedia

    2008-01-01

    Tony came from Netherton, a small town near Birmingham in the English West Midlands, where he grew up with his parents, who ran the local grocery store, "T.W. Roberts & Son". This is where he regularly liked to return, firstly to help his parents and later simply to spend time with them. Here undoubtedly lie the roots of his organizational skills and his ability to get on so well with others. He soon became interested in the rapidly-developing field of computing and this was how he first came to CERN, during the summer of 1973, at the age of 25. He joined the DD Division as an operator responsible for the "calculators" of that time, where he stayed until 1979 when he joined the Fellows and Associates Section of Personnel Division. He participated in the general computerisation of the Administration and continued his career in the Records Office of HR Department, a post he held until the end. Though still very British – ob...

  14. Robert Lévy-Mandel (1923-2010)

    CERN Multimedia

    2010-01-01

    Former CERN Director Robert Lévy-Mandel passed away on 3 July at the age of 87.   After obtaining a diploma from the Institut polytechnique in Grenoble, in 1948 he started work at the CEA, and was involved in the development and construction of the Saclay institute's first particle accelerator, a Van de Graaff machine. From 1954 to 1957 he was responsible for the coordination, development and construction of the CEA’s Saturne synchrotron, which entered service in 1958. In 1963 he was appointed head of the Saturne Synchrotron Department. The team led the construction of the Gargamelle bubble chamber, which was installed at CERN, and made contributions to other major facilities, including the Big European Bubble Chamber (BEBC). In 1971 he was invited to come to Geneva by John Adams, who was in charge of the SPS accelerator project. With the start of the SPS project, CERN had two laboratories, one at Meyrin and one at Prévessin, each with its own Director General: ...

  15. Symposium in Memory of Robert H. Siemann. Proceedings

    International Nuclear Information System (INIS)

    The Symposium in Memory of Robert H. Siemann was held on July 7th, 2009 to honor the life and achievements of one of the pioneers of accelerator physics. Speakers and participants from around the world came together at SLAC to celebrate his contributions to science and to the scientific community. Speakers from each of the chapters of Bob's life were asked to provide a broad retrospective of the man and his career. Students provided brief perspectives of specific aspects of his work, and of his role as a mentor. The Siemann family attended and offered personal reminiscences. A redwood tree and memorial plaque were dedicated on the SLAC main Green in his honor. Many who attended the event felt they had learned something they did not know about their longtime colleague. In the pages that follow, the prepared remarks and slides of speakers have been collected. The richness of the contributions and breadth of topics covered are a reflection of the richness and breadth of Bob's life. The event was video recorded, and may be viewed at the SLAC library or online through the SLAC website.

  16. The short, tragic life of Robert M. Glover.

    Science.gov (United States)

    Defalque, R J; Wright, A J

    2004-04-01

    Robert Mortimer Glover (1815-1859) was a contemporary of John Snow and James Young Simpson. Although he did not reach the standing of those two giants, his researches, writings and lectures were important contributions to the early development of British anaesthesia. Glover was the first to explore the physiological action of chloroform in the laboratory and to discover its anaesthetic effect in 1842. He helped Sir John Fife in Hannah Greener's autopsy in January 1848 and influenced Fife's conclusions on the cause of the young girl's death. His numerous and extensive articles reviewing the history, chemistry, pharmacology and clinical applications of various anaesthetics were widely read and quoted by his colleagues, including John Snow. While in Edinburgh and Newcastle, Glover was recognised as a remarkably astute physician, original researcher, prolific writer and enthusiastic lecturer with an enormous knowledge of medicine, the physical sciences, mathematics and philosophy. His brilliant career deteriorated after his arrival in London and, especially, after his return from the Crimea, although he continued to publish until the week before his death. The causes of his decline remain obscure. The last year of his life was ruined by his addiction to chloroform, to whose development he had contributed so much, and which killed him at the early age of 43. PMID:15023112

  17. Robert Dicke and the Naissance of Experimental Gravity Physics

    CERN Document Server

    Peebles, P J E

    2016-01-01

    The experimental study of gravity became much more active in the late 1950s, a change pronounced enough be termed the naissance of empirical gravity physics. A review of the developments since 1915, and up to the transition to what might be termed a normal and accepted part of physical science in the late 1960s, shows the importance of advances in technologies, here as in all branches of science. The role of contingency is illustrated by Robert Dicke's decision to change directions in mid-career, to lead a research group dedicated to the experimental study of gravity. One sees the power of nonempirical evidence, which led some in the 1950s to feel that general relativity theory is so logically sound as to be scarcely worth the testing, while Dicke and others argued that a poorly tested theory is only that, and that other nonempirical arguments, based on Mach's Principle and Dirac's Large Numbers, suggested it was worth looking for a better theory of gravity. I conclude by offering lessons from this history, s...

  18. Intervjuu American Wind Symphony Orchestra dirigendi Robert Austin Boudreau'ga = Interview with Mr. Robert Austin Boudreau, director of the American Wind Symphony Orchestra / Robert Austin Boudreau ; interv. Heli Ojamaa

    Index Scriptorium Estoniae

    Boudreau, Robert Austin

    2007-01-01

    11. IV 2007. a. tehtud telefoniintervjuu Robert A. Boudreau'ga, kellele arhitekt Louis I. Kahn disainis kontserdilaevad Point Counterpoint I (valmis 1961) ja Point Counterppoint II (kavandamist alustati 1966, valmis 1975). Louis I. Kahnist, koostööst arhitektiga ja laevadest. Selgitav kaaskiri arhitekt Heli Ojamaalt. Ill.: I laeva makett, II laeva joonised ja 4 värv. fotot

  19. Must, valge + hall : Sam Wagstaffi ja Robert Mapplethorpe'i portree / Madis Palm

    Index Scriptorium Estoniae

    Palm, Madis

    2008-01-01

    Dokumentaalfilm "Black, White & Gray: Sam Wagstaff and Robert Mapplethorpe" : autor ja režissöör James Crump : Ameerika Ühendriigid 2007. Filmi näidati filminädala "Art in America" raames Tallinnas

  20. Robert W. Kates’ Reader: A New Map of Sustainability Science and Technology

    Directory of Open Access Journals (Sweden)

    William Clark

    2011-07-01

    Full Text Available KATES, Robert W., ed. 2010. Readings in Sustainability Science and Technology. CID Working Paper No. 213. Center for International Development, Harvard University. Cambridge, MA: Harvard University, December 2010.

  1. Mission, Science, and Race in South Africa; AW Roberts of Lovedale 1883-1938

    Science.gov (United States)

    Glass, I.S.

    2016-02-01

    Book Review: Biography of Alexander William Roberts. Noted educator, variable star observer and politician who represented South African "natives" in the parliament of the Union of South Africa at a time when they had no other representation.

  2. Marian Roberts, Developing the Craft of Mediation: Reflections on Theory and Practice

    Directory of Open Access Journals (Sweden)

    Ghislaine M. Lanteigne

    2016-01-01

    Full Text Available In Developing the Craft of Mediation, Marian Roberts proposes that mediation is akin to a craft with its focus on learning from experience and from others working in the field to develop and master knowledge and skills.

  3. Kablilt Casablancasse : Eesti suurim seikleja John Robert Ignace Lepp 100 / Vello Salo

    Index Scriptorium Estoniae

    Salo, Vello, 1925-

    2009-01-01

    Eesti päritolu seikleja John Robert Lepp, Prantsusmaal tuntud kui katoliku kiriku preester Ignace Lepp, avaldas prantsuse ja saksa keeles hulgaliselt raamatuid psühholoogia, filosoofia ja religiooni valdkonnast

  4. Kventin Tarantino + Robert Rodriges = Grainhaus, ili Kinonostalgija po-amerikanski / Andrei Sozinov

    Index Scriptorium Estoniae

    Sozinov, Andrei

    2007-01-01

    Filmiprojekt "Grindhouse" koosneb Robert Rodrigueze retroõudukast "Grindhouse : Õuduste planeet" ("Planet Terror") ja Quentin Tarantino 70-ndatest inspireeritud õudusfilmist "Surmakindel" ("Death Proof") : Ameerika Ühendriigid 2007

  5. Kollaaž ja kontekst. Robert Rumase liiklusmärgid Tallinnas / Hanno Soans

    Index Scriptorium Estoniae

    Soans, Hanno, 1974-

    2004-01-01

    Sekkuv kunst. Poola kunstniku Robert Rumase (1966) rahvusvahelisest kunstiprojektist "Linnamanöövrid", Kai Kaljo videost "One way to see America", Krzysztof Wodicko "Kodutute projektsioonist" ja New York City Unioni väljaku ümberkorraldamisest

  6. MD210 Note: Creation of Hollow Bunches in the PSB

    CERN Document Server

    Oeftiger, Adrian; Findlay, Alan James; Hancock, Steven; Rumolo, Giovanni; CERN. Geneva. ATS Department

    2016-01-01

    MD210 aims for the creation of longitudinally hollow bunches in the CERN PS Booster. The first three sessions have been carried out using the radial loop feedback system in order to drive the beam on a dipolar parametric resonance (instead of the phase loop). It has been found that the damping by the phase loop inhibits the excitation of the resonance to a major extent. The hollow distributions generated under these circumstances fail to reach a satisfying bunching factor. Nonetheless, proving the principally successful application of this technique to the PS Booster promises good results once the phase loop system supports trim functions. The approach, actions and detailed results of the first three MD sessions are presented in this paper.

  7. MD 382: Beam Transfer Function and diffusion mechanisms

    CERN Document Server

    Tambasco, Claudia; Buffat, Xavier; Crouch, Matthew; Pieloni, Tatiana; Boccardi, Andrea; Fuchsberger, Kajetan; Gasior, Marek; Kotzian, Gerd; Lefevre, Thibaut; Pojer, Mirko; Salvachua Ferrando, Belen Maria; Solfaroli Camillocci, Matteo; Giachino, Rossano; CERN. Geneva. ATS Department

    2016-01-01

    The Beam Transfer Function (BTF) measurements have been previously tested in the LHC during MD block 1 and 2. Different machine configurations (i.e. energy, beam intensity, emittance etc...) have been tested to determine a safe set-up (excitation amplitude) of the system to be completely transparent to the beam (no emittance blow-up neither losses). The aim of this experiment in MD block 3 was to characterize the Stability Diagram (SD) in the presence of diffusion mechanisms induced by excited resonances due to beam-beam long range and Landau octupole interplay. During the experiment, BTF measurements have been acquired at flat top for different settings of Landau octupole current, different chromaticity values and transverse feedback gains. In this note the description of the experiment is presented together with some preliminary results.

  8. A Fast Attack Algorithm on the MD5 Hash Function

    Institute of Scientific and Technical Information of China (English)

    WANG Zhang-yi; ZHANG Huan-guo; QIN Zhong-ping; MENG Qing-shu

    2006-01-01

    The sufficient conditions for keeping desired differential path of MD5 was discussed. By analyzing the expanding of subtraction difference, differential characters of Boolean functions, and the differential characters of shift rotation, the sufficient conditions for keeping desired differential path could be obtained. From the differential characters of shift rotation, the lacked sufficient conditions were found. Then an algorithm that reduces the number of trials for finding collisions were presented. By restricting search space, search operation can be reduced tc 234 for the first block and 230 for the second block. The whole attack on the MD5 can be accomplished within 2C hours using a PC with 1.6 G CPU.

  9. Michael C. Roberts: award for distinguished contributions to education and training in psychology.

    Science.gov (United States)

    2006-11-01

    Presents a citation for Michael C. Roberts, who received the Award for Distinguished Contributions to Education and Training in Psychology "for his dedication to the education, training, and mentoring of psychologists from undergraduate study through professional career." Accompanying the citation are a brief profile and a selected bibliography, as well as Roberts' award address, entitled Essential Tension: Specialization With Broad and General Training in Psychology. ((c) 2006 APA, all rights reserved). PMID:17115832

  10. Boyling over: a commentary on the preceding papers [delivered at the 'Psychoanalysing Robert Boyle' meeting

    OpenAIRE

    Cantor, G.

    1999-01-01

    [FIRST PARAGRAPHS] When Michael Hunter first publicized the idea of `Psychoanalysing Robert Boyle' I understood that his main aim was to test three competing psychoanalytical theories against the historical evidence provided by the life and work of Robert Boyle. Although this would have been a valuable exercise, and one that the British Society for the History of Science meeting partly engaged, the papers by Brett Kahr, John Clay and Karl Figlio published here raise some fa...

  11. Globalization and Religion: The Case of Malacca and the Work of Robert Morrison

    OpenAIRE

    Peter Tze Ming Ng

    2012-01-01

    Religion has long been a significant factor in the process of globalization. In this article, the author attempts to explore and review religious factors involved in the history of Malacca (Melaka) and in the missionary work of Robert Morrison in the early 19th century. Malacca has long been a meeting place for various religions in their respective processes of globalization. Robert Morrison was the first Protestant Missionary to come to the Chinese Mainland. He arrived in 1807. However, afte...

  12. 1913年8月:Robert Millikan和他的油滴实验

    Institute of Scientific and Technical Information of China (English)

    萧如珀; 杨信男

    2007-01-01

    @@ Robert Millikan著名的油滴实验发表于1913年8月,对以往测量电子电荷的方式做了大幅改良,很精巧地测出基本电荷量,被誉为物理史上最巧妙的实验之一,但它也成了指控Robert Millikan在科学行为上有瑕疵的根据.

  13. Towards automatic coupling corrections with DOROS BPMs (MD750)

    CERN Document Server

    Persson, Tobias Hakan Bjorn; Langner, Andy Sven; Lefevre, Thibaut; Maclean, Ewen Hamish; Malina, Lukas; Olexa, Jakub; Skowronski, Piotr Krzysztof; Garcia-Tabares Valdivieso, Ana; Coello De Portugal - Martinez Vazquez, Jaime Maria; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

    2015-01-01

    BPMs close to IP1 and IP5 have been equipped with the new DOROS (Diode ORbit OScillation) system which provides precise orbit and turn-by-turn data [1]. In this MD-note we report on the rst measurements with the DOROS system to measure the transverse coupling. Furthermore, we compare the results and the performance of the system to the normal BPMs.

  14. MD 349: Impedance Localization with AC-dipole

    CERN Document Server

    Biancacci, Nicolo; Metral, Elias; Salvant, Benoit; Papotti, Giulia; Persson, Tobias Hakan Bjorn; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

    2016-01-01

    The purpose of this MD is to measure the distribution of the transverse impedance of the LHC by observing the phase advance variation with intensity between the machine BPMs. Four injected bunches with different intensities are excited with an AC dipole and the turn by turn data is acquired from the BPM system. Through post-processing analysis the phase variation along the machine is depicted and, from this information, first conclusions of the impedance distribution can be drawn.

  15. Analytical applications of MD-FIA-optical detection systems

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A brief introduction of recent research works in our laboratory concerning microdialysis(MD) based on optical detection combined with FIA is made in this mini-review. A biosensor system has been designed and realized the real time in vivo monitoring of some important clinic substances such as calcium, uric acid. The system has also been used to study the in vitro binding of drug-protein.

  16. Application of MD Simulations to Predict Membrane Properties of MOFs

    OpenAIRE

    Elda Adatoz; Seda Keskin

    2015-01-01

    Research Article Application of MD Simulations to Predict Membrane Properties of MOFs Elda Adatoz and Seda Keskin Chemical and Biological Engineering, Koc University, Rumelifeneri Yolu, Sariyer, 34450 Istanbul, Turkey Correspondence should be addressed to Seda Keskin; Received 22 May 2015; Accepted 13 July 2015 Academic Editor: Yanlin Song Copyright © 2015 E. Adatoz and S. Keskin. This is an open access article distributed under the Creative Commons A...

  17. A Secure Hash Function MD-192 With Modified Message Expansion

    OpenAIRE

    Harshvardhan Tiwari; Dr. Krishna Asawa

    2010-01-01

    Cryptographic hash functions play a central role in cryptography. Hash functions were introduced in cryptology to provide message integrity and authentication. MD5, SHA1 and RIPEMD are among the most commonly used message digest algorithm. Recently proposed attacks on well known and widely used hash functions motivate a design of new stronger hash function. In this paper a new approach is presented that produces 192 bit message digest and uses a modified message expansion mechanism which gene...

  18. MD 754: Instability Threshold for Train with 25ns Spacing

    CERN Document Server

    Carver, Lee Robert; Biancacci, Nicolo; Iadarola, Giovanni; Levens, Tom; Metral, Elias; Salvant, Benoit; Wang, Na; CERN. Geneva. ATS Department

    2016-01-01

    Measurements made since the beginning of run II at 6.5 TeV have shown that there is a large discrepancy in the instability thresholds between single bunches and trains of 72 bunches with 25ns spacing, whereas the same result is expect for pure impedance-induced instabilities. One possible explanation is that the presence of electron cloud is affecting the beam stability. This MD will attempt to determine if electron cloud is the dominant mechanism affecting beam stability.

  19. Can maitake MD-fraction aid cancer patients?

    Science.gov (United States)

    Kodama, Noriko; Komuta, Kiyoshi; Nanba, Hiroaki

    2002-06-01

    Maitake mushroom (Grifola frondosa) MD-fraction containing beta-1,6 glucan with beta-1,3 branched chains has previously exhibited strong anticancer activity by increasing immune-competent cell activity.1,2 In this non-random case series, a combination of MD-fraction and whole maitake powder was investigated to determine its effectiveness for 22- to 57-year-old cancer patients in stages II-IV. Cancer regression or significant symptom improvement was observed in 58.3 percent of liver cancer patients, 68.8 percent of breast cancer patients, and 62.5 percent of lung cancer patients. The trial found a less than 10-20 percent improvement for leukemia, stomach cancer, and brain cancer patients. Furthermore, when maitake was taken in addition to chemotherapy, immune-competent cell activities were enhanced 1.2-1.4 times, compared with chemotherapy alone. Animal studies have supported the use of maitake MD-fraction for cancer. PMID:12126464

  20. Review of 40-year MD theses in Medical Oncology

    International Nuclear Information System (INIS)

    Background and objective: It is almost 40 years since the foundation of the Medical Oncology (MO) Department. We aimed to appraise the clinical research to fulfill the Medical Doctorate (MD) degree in MO at the National Cancer Institute, Cairo University (NCI, CU). Methods: This review included 62 MD theses containing 66 studies. They were reviewed regarding aims, type of study, clinical trial phase, design and methodology, statistical tests, results, limitations, consent and IRB approval. Theses were grouped into 3 periods: 1970-1989, 1990-1999 and 2000- 2008. Results: Almost 76% of the studies were interventional and 24% were observational. Informed consent and Institutional Review Board approval were mentioned in 18 and 2 studies, respectively. While all studies mentioned the aims, none, clearly mentioned the research question. Outcomes were mainly efficacy followed by safety. Study design was inadequately considered, especially in 70’s–80’s period (p = 0.038). Median sample size and study duration were almost stable through the three periods (p = 0.441, 0.354, respectively). Most of the studies used both descriptive and analytical statistical methods. In a descending order, researched cancers were lymphoma, breast, leukemia, liver, urinary bladder, lung and colorectal. The commonest stages researched were IV and III. The number of studies focused on assessing biomarkers, biomarkers plus drugs/procedures, drugs and procedures are 20, 20, 16 and 6, respectively. Conclusion: With time, research within MD theses in MO increased quantitatively and qualitatively. Improvements were noticeable in documentation of study design.

  1. Structure and Properties of HELICAL CARBON NANOTUBES through MD Simulations

    Science.gov (United States)

    Dahiya, Akshay; Verma, Deepti; Gupta, Shakti S.

    Helical Carbon Nanotubes (HCNTs) are coiled 3-valent carbon networks which represent pure carbon helix. Here we study the geometries of two classes: hexagonal helix containing purely polyhex networks and the second class with 5-and 7-membered rings besides hexagons. We followed a model of hexagonal, single wall HCNTs, and determined their relaxed configuration using MD simulations based on Tersoff potential. A race-track like structure is observed in the cross-section of HCNTs upon minimization. For generating class two helix, the adjacency matrix eigenvector's (AME) method is applied which utilizes 3-coordinated tiling of the plane by 5-,6-,and 7-membered ring for the construction of helical structures. The application of the AME method to torusenes is crucial for class two helix generation as it is based on an appropriate choice of bi-lobial eigenvectors triplet which can be selected on the basis of their nodal properties as verified here. After 3-D transformations the final structure was obtained with the help of MM3-potential based MD simulations on Tinker commercial code. The spring constants of HCNTs are computed through MD simulations.

  2. Robert Klopstock and Franz Kafka--the friends from Tatranské Matliare (the High Tatras).

    Science.gov (United States)

    Mydlík, M; Derzsiová, K

    2007-01-01

    The paper summarises the accessible literature on the life and work of well-known American lung surgeon, Professor Dr. Med. Robert Klopstock, who was in the years 1920-1924 a friend Franz Kafka. Professor Klopstock was of Hungarian origin and he got acquainted with Franz Kafka at the end of the year 1920 in Tatranské Matliare (The High Tatras). They were both patients treated for lung tuberculosis. They became close friends and their mutual correspondence shows their real friendship. Robert Klopstock was present at Franz Kafka's death-bed on June 3, 1924 in Kierling, near Klosterneuburg, not far from Vienna. Robert Klopstock studied at Medical Faculties of the Universities in Budapest, Prague, Kiel and Berlin. After his graduation in 1933 in Berlin, he worked as a lung surgeon at various surgical clinics and departments in Budapest and Berlin. In 1936 Robert Klopstock together with his wife visited the High Tatras and Tatranské Matliare. In 1937 Robert Klopstock with his wife Gizela, a writer and a translator, who translated the first chapters of Franz Kafka's novel "Trial" into Hungarian language, went to United States of America. During his stay in U.S.A. Dr. Med. Robert Klopstock was very active as a lung surgeon and a scientist. He published 64 specialized scientific papers, mostly in American medical journals. He became Professor of Lung Surgery at Downstate Medical Centre in New York-Brooklyn. He died on June 15, 1972 in New York. PMID:18225646

  3. Implementation of MD5 Fast Decryption Algorithm Based on Graphic Processing Unit%基于GPU的MD5高速解密算法的实现

    Institute of Scientific and Technical Information of China (English)

    乐德广; 常晋义; 刘祥南; 郭东辉

    2010-01-01

    MD5快速碰撞算法由于不支持逆向过程而无法在MD5密码攻击中得到实际应用.针对上述问题,通过分析基于图形处理单元(GPU)的MD5密码并行攻击算法原理,设计基于GPU的MD5高速解密算法,在此基础上实现一个MD5高速密码攻击系统.测试结果证明,该算法能有效加快MD5密码破解速度.

  4. Application of MD5 Algorithm in Database System%MD5算法在数据库系统中的应用

    Institute of Scientific and Technical Information of China (English)

    罗金涛

    2013-01-01

    数据加密是保护数据安全的重要手段,MD5是目前信息安全领域中使用比较广泛的加密算法,对MD5算法的原理进行了分析,并将MD5算法应用在数据库的登录验证过程中.

  5. The Application Research of MD5 Encryption Algorithm in DCT Digital Watermarking

    Science.gov (United States)

    Xijin, Wang; Linxiu, Fan

    This article did the preliminary study of the application of algorithm for MD5 in the digital watermark. It proposed that copyright information will be encrypted using an algorithm MD5, and made rules for the second value image watermarks, through DCT algorithm that embeds an image by the carrier. The extraction algorithms can pick up the watermark and restore MD5 code.

  6. Application of MD5 Encryption Algorithm Based on C# Technology%基于C#技术的MD5加密算法的应用

    Institute of Scientific and Technical Information of China (English)

    王倩丽

    2010-01-01

    在对Message-Digest Algorithm 5进行简要描述的同时,对MD5算法的原理作深入分析.运用MD5算法,采用目前流行的C#语言进行了具体研究,设计了MD5加密演示系统,经过测试该系统可以准确实现数据的MD5加密.

  7. MD5算法在用户口令认证中的应用%The Application of MD5 Algorithm in The User Password Authentication

    Institute of Scientific and Technical Information of China (English)

    刘洪民; 印帮辉

    2014-01-01

    MD5算法是目前比较安全且易用的加密算法,其在密码领域有着举足轻重的地位.本文通过介绍MD5算法的特点及加密原理,分析了MD5算法在用户口令认证中的安全隐患,给出了用户口令认证应用中如何提高MD5算法安全性的措施和方法.

  8. The Robert E. Hopkins Center for Optical Design and Engineering

    Science.gov (United States)

    Zavislan, James M.; Brown, Thomas G.

    2008-08-01

    preparation for these students. While this extracurricular experience is truly world-class, an integrated design experience defined within our academic program is increasingly necessary for those going on to professional careers in engineering. This paper describes the philosophy behind a revision to our undergraduate curriculum that integrates a design experience and describes the engineering laboratory that has been established to make it a reality. The laboratory and design center has been named in honor of Robert E. Hopkins, former director and professor, co-founder of Tropel corporation, and a lifelong devotee to engineering innovation.

  9. Roberts Bank: Ecological crucible of the Fraser River estuary

    Science.gov (United States)

    Sutherland, Terri F.; Elner, Robert W.; O'Neill, Jennifer D.

    2013-08-01

    Roberts Bank, part of the Fraser River delta system on Canada's Pacific coast, is a dynamic estuarine environment supporting important fisheries as well as internationally significant populations of migratory shorebirds. The 8000 ha bank environment comprises a complex of riparian boundaries, intertidal marshes, mud and sand flats, eelgrass meadows, macroalgae and biofilms. Anthropogenic developments (a ferry causeway in 1961 and a port causeway in 1969) have been responsible for changes in tidal flow patterns, tidal elevation, sediment transport and the net expansion of eelgrass beds. The goals of the present study were to (1) directly compare geotechnical properties spanning each side of the coalport causeway, and (2) enhance our understanding of the intercauseway ecosystem under a high-resolution sampling design. Sediment properties (grain size, porosity, organic content, and chlorophyll) and biological communities (eelgrass, macrofauna (0.5-1.0 mm) and meiofauna (0.063-0.5 mm)) were surveyed in 1997 at three stations outside the intercauseway area and three lateral transects spanning the intercauseway tidal flat at tidal heights representing three different habitats: biofilm, Zostera japonica, and Zostera marina. A fine-silt organic-rich porous deposit was observed on the shoreward north side of the coalport causeway relative to the south counterpart, suggesting that consolidation and erosion processes could likely not keep pace with the deposition of Fraser River silt. High chlorophyll levels were found in the protected shoreward northern border of the ferry causeway where fine sands dominate and higher water transparency exists, owing to the redirection of the silt-laden river plume by the coalport causeway. Principle Components Analysis revealed a positive relationship between these porous, organic-rich sediments and cumacean abundance in all regions where eelgrass was absent, including the north side of the coalport causeway. Further, a positive

  10. Obituary: Ralph Robert Robbins, Jr., 1938-2005

    Science.gov (United States)

    Hemenway, Mary Kay; Jefferys, William H.; Lambert, David L.

    2007-12-01

    Ralph Robert Robbins, Jr., died on 2 December 2005, in Kyle, Texas. His wife, Maria Elena Robbins, his daughters Julia Robbins Kelso and Stephanie Juarez Balles, his son Matthew Juarez, and five grandchildren survive him. Bob was on the faculty at the University of Texas from 1968 until his retirement in 2003. Bob was born in Wichita, Kansas, on 2 September 1938, the only son of Mildred and Ralph Robert Robbins, Sr. Guided by his high school's policy to provide a practical education to children of working-class parents, Bob began high school with a heavy dose of vocational courses until the results of a test indicated his special talent in mathematics. He was awarded a full scholarship to Yale University, graduating magna cum laude in mathematics in 1960. He won the Warner Prize in Mathematics at Yale that year. He received his Ph.D. in 1966 with a dissertation entitled "The Triplet Spectrum of Neutral Helium in Expanding Nebulae" from the University of California at Berkeley. His interest in college teaching was ignited at this time through summer teaching positions at San Mateo California Junior College and the Ohio State University. Following a year at Texas as a McDonald Observatory Post-doctoral Fellow, Bob taught for a year in the physics department of the University of Houston before returning to the University of Texas at Austin as an Assistant Professor of Astronomy in 1968. He was promoted to Associate Professor in 1972. Bob's research in the early 1970s on theoretical studies of helium was of vital importance to astronomers for over three decades. These pioneering calculations became vital to observational astronomers in the mid-1990s as interest grew in the primordial helium produced by the Big Bang. Bob's interest and influence in education was international in scope. In the summers 1968-1970, he was a government consultant in Mathematics in East Pakistan (now Bangladesh). He consulted with the government that was preparing a master plan for technical

  11. A Secure Hash Function MD-192 With Modified Message Expansion

    CERN Document Server

    Tiwari, Harshvardhan

    2010-01-01

    Cryptographic hash functions play a central role in cryptography. Hash functions were introduced in cryptology to provide message integrity and authentication. MD5, SHA1 and RIPEMD are among the most commonly used message digest algorithm. Recently proposed attacks on well known and widely used hash functions motivate a design of new stronger hash function. In this paper a new approach is presented that produces 192 bit message digest and uses a modified message expansion mechanism which generates more bit difference in each working variable to make the algorithm more secure. This hash function is collision resistant and assures a good compression and preimage resistance.

  12. 散列算法MD5和SHA-1的比较%Comparison between MD5 and SHA-1

    Institute of Scientific and Technical Information of China (English)

    王泽; 曹莉莎

    2016-01-01

    MD5 and SHA-1 are the two known Hash Algorithm which are widely applied in information security, they are both developed from MD4.This paper introduces their algorithm logic in detail, compares them though simulation experiment ,soft-ware testing, etc. Finally, it draw a conclusion:The SHA-1 algorithm is more secure than the MD5 algorithm, but in the same hardware, SHA-1 is slower than MD5.%MD5和SHA-1是两个已知的广泛应用于信息安全的散列算法,均由MD4发展而来。详细介绍了它们的算法逻辑,并通过模拟实验、软件测试等方式对其在各个方面进行比较,最终得出结论:SHA-1算法比MD5算法的安全性更高,但在同一硬件上,SHA-1比MD5运行的要慢。

  13. EDITORIAL: Roberts Prize for the best paper published in 2012 Roberts Prize for the best paper published in 2012

    Science.gov (United States)

    Cherry, Simon; Ruffle, Jon

    2013-08-01

    The publishers of Physics in Medicine and Biology (PMB), IOP Publishing, in association with the journal owners, the Institute of Physics and Engineering in Medicine (IPEM), jointly award the Roberts prize for the best paper published in PMB during the previous year. The procedure for deciding the winner is a two-stage process. First, a shortlist of contenders is drawn up based on those papers that had the best referees' quality assessments, with a further quality check and endorsement by the Editorial Board. The papers on the shortlist are then reviewed by a specially convened IPEM committee consisting of members with fellow status. This committee reads the shortlisted papers and selects the winner. We have much pleasure in advising readers that the Roberts Prize for the best paper published in 2012 is awarded to Michel Defrise, Ahmadreza Rezaei and Johan Nuyts from the Vrije Universiteit Brussels and the Katholieke Universiteit Leuven, Belgium for their breakthrough paper that describes how the information needed for attenuation correction in PET imaging can be extracted, to within a constant, from time-of-flight emission data: Time-of-flight PET data determine the attenuation sinogram up to a constant 2012 Phys. Med. Biol. 57 885 Michel Defrise1, Ahmadreza Rezaei2 and Johan Nuyts2 1Department of Nuclear Medicine, Vrije Universiteit Brussel, B-1090 Brussels, Belgium 2Department of Nuclear Medicine, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium This paper represents an important and timely contribution to the literature as time-of-flight PET scanners are now offered by several manufacturers. In hybrid PET/CT scanners, the PET attenuation correction, necessary for quantitative reconstruction of the tracer distribution, can be derived directly from the CT data. Sometimes, however, the PET and CT scans may be poorly aligned due to patient motion and other approaches are needed. In addition, hybrid PET/MRI scanners also, have been developed recently, and in

  14. How to build analogues of the Bessel-Clifford expansions for the sum of the repulsive Coulomb potential and central potential decreasing more rapidly than the centrifugal one?

    International Nuclear Information System (INIS)

    The suggested algorithm is based on a linear version of the variable phase approach. The regular and irregular wave-functions of scattering by the above sum of potentials are represented as an infinite series in which the distance and momentum are separated from each other as well as in the Bessel - Clifford expansions for the Coulomb functions. The construction of the finite uniformly approximating these series under well-defined conditions is reduced to the solution of the simplest differential problems. 12 refs

  15. MD5加密算法的研究及应用%Research and application of MD5 encryption algorithm

    Institute of Scientific and Technical Information of China (English)

    魏晓玲

    2010-01-01

    针对当前网站建设和系统开发中用户信息等重要数据的安全问题,提出了一种MD5加密算法,可以对用户密码进行加密.MD5加密算法是一种比较常用的单向加密算法,通过对该算法的深入研究,介绍了MD5算法的特性、算法原理及其算法流程,并给出MD5算法在一个具体系统中的实际应用,得出MD5算法是一种非常安全和易用的加密算法.

  16. Reverse Crack of MD5 Encryption and Its Safety Improvement%MD5加密逆向破解及安全性改进

    Institute of Scientific and Technical Information of China (English)

    王雄; 朱志祥; 许辉辉

    2014-01-01

    针对消息摘要算法第五版(Message-Digest Algorithm 5,MD5)不可逆的特性,通过组建Oracle明文数据库、调用MD5函数,建立明文与MD5码之间的一一对应关系,实现了对MD5加密的逆向破解.从应对碰撞攻击和反向查询两方面,总结多种改进措施,提高了MD5加密算法在实际应用中的安全性.

  17. Das Fortbildungsangebot der Bibliothek des Robert Koch-Instituts: Dienstleistung im Publikationsprozess

    Directory of Open Access Journals (Sweden)

    Senst, Henriette

    2013-12-01

    Full Text Available [english] Robert Koch-Institute’s scientists are supported during the publishing process in different ways. Relating to frequently asked questions the library offers trainings, which are integrated in the training program of the institute.How does a good literature research work? How do I manage my literature and how do I cite correctly? What do I have to consider during the publishing process? These and other questions are answered in trainings on literature research, managing bibliographies with EndNote and “Scientific Publishing in the Robert Koch-Institute” which take place regularly.

  18. Some Pb and Sr isotopic measurements on eclogites from the Roberts Victor Mine, South Africa.

    Science.gov (United States)

    Manton, W. I.; Tatsumoto, M.

    1971-01-01

    Five nodules of eclogite, one nodule of garnet peridotite, and one sample of kimberlite from the Roberts Victor Mine in the Orange Free State were analyzed for concentrations of U, Th, Pb, Rb, and Sr, and also isotopic compositions of Pb and Sr. Results are presented and analyzed. They indicate that the Roberts Victor eclogites have been contaminated by lead from the host rock of kimberlite. This finding suggests that stepwise extraction of lead may be a means of obtaining the isotopic composition of the primary lead in kimberlitic eclogites.

  19. American Prometheus. The Triumph and Tragedy of J. Robert Oppenheimer. Biography

    International Nuclear Information System (INIS)

    A definitive portrait of legendary scientist J. Robert Oppenheimer, the ''father'' of the atomic bomb, discusses his seminal role in the twentieth-century scientific world, as well as his lesser-known roles as family man, supposed communist, and head of Princeton's Institute for Advanced Studies. ''American Prometheus'' is a rich evocation of America in mid-century and a compelling portrait of scientist J. Robert Oppenheimer, a man shaped by its major events--the Depression, World War II, and the Cold War. (orig.)

  20. Robert Lacoste's the darker side practical applications for electronic design concepts from circuit cellar

    CERN Document Server

    Lacoste, Robert

    2009-01-01

    Robert Lacoste's The Darker Side column has quickly become a must read among Circuit Cellar devotees. His column provides readers with succinct theoretical concepts and practical applications on topics as far reaching as digital modulation to antenna basics. Difficult concepts are demystified as Robert shines a light on complex topics within electronic design.This book collects sixteen Darker Side articles that have been enriched with new, exclusive content from the author. An intro into The Darker Side will give examples of material that can enhance and optimize the way you design. A