Minimal Gromov-Witten rings

International Nuclear Information System (INIS)

Przyjalkowski, V V

2008-01-01

We construct an abstract theory of Gromov-Witten invariants of genus 0 for quantum minimal Fano varieties (a minimal class of varieties which is natural from the quantum cohomological viewpoint). Namely, we consider the minimal Gromov-Witten ring: a commutative algebra whose generators and relations are of the form used in the Gromov-Witten theory of Fano varieties (of unspecified dimension). The Gromov-Witten theory of any quantum minimal variety is a homomorphism from this ring to C. We prove an abstract reconstruction theorem which says that this ring is isomorphic to the free commutative ring generated by 'prime two-pointed invariants'. We also find solutions of the differential equation of type DN for a Fano variety of dimension N in terms of the generating series of one-pointed Gromov-Witten invariants

Ring Theory

CERN Document Server

Jara, Pascual; Torrecillas, Blas

1988-01-01

The papers in this proceedings volume are selected research papers in different areas of ring theory, including graded rings, differential operator rings, K-theory of noetherian rings, torsion theory, regular rings, cohomology of algebras, local cohomology of noncommutative rings. The book will be important for mathematicians active in research in ring theory.

Geometry of time-spaces non-commutative algebraic geometry, applied to quantum theory

CERN Document Server

Landau, Olav Arnfinn

2011-01-01

This is a monograph about non-commutative algebraic geometry, and its application to physics. The main mathematical inputs are the non-commutative deformation theory, moduli theory of representations of associative algebras, a new non-commutative theory o

Outer Measures on a Commutative Ring Induced by Measures on Its Spectrum

Directory of Open Access Journals (Sweden)

Dudzik Dariusz

2017-09-01

Full Text Available On a commutative ring R we study outer measures induced by measures on Spec(R. The focus is on examples of such outer measures and on subsets of R that satisfy the Carathéodory condition.

Matrix models as non-commutative field theories on R3

International Nuclear Information System (INIS)

Livine, Etera R

2009-01-01

In the context of spin foam models for quantum gravity, group field theories are a useful tool allowing on the one hand a non-perturbative formulation of the partition function and on the other hand admitting an interpretation as generalized matrix models. Focusing on 2d group field theories, we review their explicit relation to matrix models and show their link to a class of non-commutative field theories invariant under a quantum-deformed 3d Poincare symmetry. This provides a simple relation between matrix models and non-commutative geometry. Moreover, we review the derivation of effective 2d group field theories with non-trivial propagators from Boulatov's group field theory for 3d quantum gravity. Besides the fact that this gives a simple and direct derivation of non-commutative field theories for the matter dynamics coupled to (3d) quantum gravity, these effective field theories can be expressed as multi-matrix models with a non-trivial coupling between matrices of different sizes. It should be interesting to analyze this new class of theories, both from the point of view of matrix models as integrable systems and for the study of non-commutative field theories.

Modular Theory, Non-Commutative Geometry and Quantum Gravity

Directory of Open Access Journals (Sweden)

Wicharn Lewkeeratiyutkul

2010-08-01

Full Text Available This paper contains the first written exposition of some ideas (announced in a previous survey on an approach to quantum gravity based on Tomita-Takesaki modular theory and A. Connes non-commutative geometry aiming at the reconstruction of spectral geometries from an operational formalism of states and categories of observables in a covariant theory. Care has been taken to provide a coverage of the relevant background on modular theory, its applications in non-commutative geometry and physics and to the detailed discussion of the main foundational issues raised by the proposal.

On generalized co-Cohen-Macaulay and co-Buchsbaum modules over commutative rings

International Nuclear Information System (INIS)

Nguyen Tu Cuong; Nguyen Thi Dung; Le Thanh Nhan

2004-07-01

We study two classes of Artinian modules over commutative Noetherian rings called co-Buchsbaum modules and generalized co-Cohen-Macaulay modules. Some properties on q-weak co-sequences, co-standard sequences, multiplicity, local homology modules, localization, etc, of these modules are presented. (author)

Non-topological non-commutativity in string theory

International Nuclear Information System (INIS)

Guttenberg, S.; Herbst, M.; Kreuzer, M.; Rashkov, R.

2008-01-01

Quantization of coordinates leads to the non-commutative product of deformation quantization, but is also at the roots of string theory, for which space-time coordinates become the dynamical fields of a two-dimensional conformal quantum field theory. Appositely, open string diagrams provided the inspiration for Kontsevich's solution of the long-standing problem of quantization of Poisson geometry by virtue of his formality theorem. In the context of D-brane physics non-commutativity is not limited, however, to the topological sector. We show that non-commutative effective actions still make sense when associativity is lost and establish a generalized Connes-Flato-Sternheimer condition through second order in a derivative expansion. The measure in general curved backgrounds is naturally provided by the Born-Infeld action and reduces to the symplectic measure in the topological limit, but remains non-singular even for degenerate Poisson structures. Analogous superspace deformations by RR-fields are also discussed. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Computational linear and commutative algebra

CERN Document Server

Kreuzer, Martin

2016-01-01

This book combines, in a novel and general way, an extensive development of the theory of families of commuting matrices with applications to zero-dimensional commutative rings, primary decompositions and polynomial system solving. It integrates the Linear Algebra of the Third Millennium, developed exclusively here, with classical algorithmic and algebraic techniques. Even the experienced reader will be pleasantly surprised to discover new and unexpected aspects in a variety of subjects including eigenvalues and eigenspaces of linear maps, joint eigenspaces of commuting families of endomorphisms, multiplication maps of zero-dimensional affine algebras, computation of primary decompositions and maximal ideals, and solution of polynomial systems. This book completes a trilogy initiated by the uncharacteristically witty books Computational Commutative Algebra 1 and 2 by the same authors. The material treated here is not available in book form, and much of it is not available at all. The authors continue to prese...

Star products from commutative string theory

Indian Academy of Sciences (India)

in commutative open-string theory performed in [2], and an impressive ... formed to all orders in the derivative expansion, but keeping only terms of order(F 2) ... nonlogarithmic finite parts [2] and come from propagators for which there is no self-.

Commutative monads as a theory of distributions

DEFF Research Database (Denmark)

Kock, Anders

2012-01-01

It is shown how the theory of commutative monads provides an axiomatic framework for several aspects of distribution theory in a broad sense, including probability distributions, physical extensive quantities, and Schwartz distributions of compact support. Among the particular aspects considered...... here are the notions of convolution, density, expectation, and conditional probability....

Bootstrapping non-commutative gauge theories from L∞ algebras

Science.gov (United States)

Blumenhagen, Ralph; Brunner, Ilka; Kupriyanov, Vladislav; Lüst, Dieter

2018-05-01

Non-commutative gauge theories with a non-constant NC-parameter are investigated. As a novel approach, we propose that such theories should admit an underlying L∞ algebra, that governs not only the action of the symmetries but also the dynamics of the theory. Our approach is well motivated from string theory. We recall that such field theories arise in the context of branes in WZW models and briefly comment on its appearance for integrable deformations of AdS5 sigma models. For the SU(2) WZW model, we show that the earlier proposed matrix valued gauge theory on the fuzzy 2-sphere can be bootstrapped via an L∞ algebra. We then apply this approach to the construction of non-commutative Chern-Simons and Yang-Mills theories on flat and curved backgrounds with non-constant NC-structure. More concretely, up to the second order, we demonstrate how derivative and curvature corrections to the equations of motion can be bootstrapped in an algebraic way from the L∞ algebra. The appearance of a non-trivial A∞ algebra is discussed, as well.

Non(anti)commutative N = (1,1/2) supersymmetric U(1) gauge theory

International Nuclear Information System (INIS)

Araki, Takeo; Ito, Katsushi; Ohtsuka, Akihisa

2005-01-01

We study a reduction of deformation parameters in non(anti)commutative N = 2 harmonic superspace to those in non(anti)commutative N = 1 superspace. By this reduction we obtain the exact gauge and supersymmetry transformations in the Wess-Zumino gauge of non(anti)commutative N = 2 supersymmetric U(1) gauge theory defined in the deformed harmonic superspace. We also find that the action with the first order correction in the deformation parameter reduces to the one in the N = 1 superspace by some field redefinition. We construct deformed N = (1,1/2) supersymmetry in N = 2 supersymmetric U(1) gauge theory in non(anti)commutative N = 1 superspace

Note on Ideal Based Zero-Divisor Graph of a Commutative Ring

Directory of Open Access Journals (Sweden)

Mallika A.

2017-12-01

Full Text Available In this paper, we consider the ideal based zero divisor graph ΓI(R of a commutative ring R. We discuss some graph theoretical properties of ΓI(R in relation with zero divisor graph. We also relate certain parameters like vertex chromatic number, maximum degree and minimum degree for the graph ΓI(R with that of Γ(R/I . Further we determine a necessary and sufficient condition for the graph to be Eulerian and regular.

Point-splitting analysis of commutator anomalies in non-abelian chiral gauge theories

International Nuclear Information System (INIS)

Ghosh, S.; Banerjee, R.

1988-01-01

A gauge covariant point-splitting regularisation is employed to calculate different anomalous commutators in four dimensional chiral gauge theories. For an external gauge field the fixed time anomalous commutator of the gauge group generators is seen to violate the Jacobi identity. The cohomological prediction can be confirmed provided the electric fields do not commute. Other commutators like the current-current and current-electric field are consistent with the Bjorken-Johnson-Low (BJL) derivation. (orig.)

DSR Theories, Conformal Group and Generalized Commutation Relation

International Nuclear Information System (INIS)

Leiva, Carlos

2006-01-01

In this paper the relationship of DSR theories and Conformal Group is reviewed. On the other hand, the relation between DSR Magueijo Smolin generators and generalized commutation relations is also shown

Novel theory of the human brain: information-commutation basis of architecture and principles of operation

Directory of Open Access Journals (Sweden)

Bryukhovetskiy AS

2015-02-01

Full Text Available Andrey S Bryukhovetskiy Center for Biomedical Technologies, Federal Research and Clinical Center for Specialized Types of Medical Assistance and Medical Technologies of the Federal Medical Biological Agency, NeuroVita Clinic of Interventional and Restorative Neurology and Therapy, Moscow, Russia Abstract: Based on the methodology of the informational approach and research of the genome, proteome, and complete transcriptome profiles of different cells in the nervous tissue of the human brain, the author proposes a new theory of information-commutation organization and architecture of the human brain which is an alternative to the conventional systemic connective morphofunctional paradigm of the brain framework. Informational principles of brain operation are defined: the modular principle, holographic principle, principle of systematicity of vertical commutative connection and complexity of horizontal commutative connection, regulatory principle, relay principle, modulation principle, “illumination” principle, principle of personalized memory and intellect, and principle of low energy consumption. The author demonstrates that the cortex functions only as a switchboard and router of information, while information is processed outside the nervous tissue of the brain in the intermeningeal space. The main structural element of information-commutation in the brain is not the neuron, but information-commutation modules that are subdivided into receiver modules, transmitter modules, and subscriber modules, forming a vertical architecture of nervous tissue in the brain as information lines and information channels, and a horizontal architecture as central, intermediate, and peripheral information-commutation platforms. Information in information-commutation modules is transferred by means of the carriers that are characteristic to the specific information level from inductome to genome, transcriptome, proteome, metabolome, secretome, and magnetome

Investigations on the renormalizability of a non-commutative u(1) gauge theory

International Nuclear Information System (INIS)

Rofner, A.

2009-01-01

When considering very small scales near the Planck-length, or equivalently very high energies (far from being reached by today's particle accelerators), space-time is expected to be quantized. Today, all but one forces governing nature (i.e. gravitation) are described via Quantum Field Theories (short QFTs) and more precisely gauge field theories (GFTs). Their heart is the art of renormalization, which allows to handle the divergences for high internal momenta appearing in the course of the perturbative development of the action in a consistent manner. Over the last years numerous attempts have been made to formulate consistent and renormalizable theories also on non-commutative spaces. Yet, it is the latter that represents a major problem for non-commutative QFTs: generally, the non-commutativity is implemented via the so-called star product, which in the simplest case is given by the Moyal-Weyl product, and which leads to a modification of the interaction terms of the theories by introducing additional phase factors depending on the non-commutative parameter theta. Then, this phase leads to a mixing of high and low energies, which is directly linked to the appearance of a new class of divergences for small momenta. While there exist various traditional renormalization schemes in order to handle uV divergences, their counterparts in the IR sector form a major obstacle in formulating consistent non-commutative QFTs. However, a first way out of this misery could be achieved by Grosse and Wulkenhaar for a scalar model. The idea was to add a suitable term to the action, in their case an oscillator term, leading to a decoupling of the high and low energy sectors. Later, the same philosophy has been followed by Gurau et. al. by adding a 1/p 2 like term to the scalar action. Both models have been shown to be renormalizable, and additionally, the latter model leads to a translation invariant propagator, which implies momentum conservation in all space points. Now, the

Space/time non-commutative field theories and causality

International Nuclear Information System (INIS)

Bozkaya, H.; Fischer, P.; Pitschmann, M.; Schweda, M.; Grosse, H.; Putz, V.; Wulkenhaar, R.

2003-01-01

As argued previously, amplitudes of quantum field theories on non-commutative space and time cannot be computed using naive path integral Feynman rules. One of the proposals is to use the Gell-Mann-Low formula with time-ordering applied before performing the integrations. We point out that the previously given prescription should rather be regarded as an interaction-point time-ordering. Causality is explicitly violated inside the region of interaction. It is nevertheless a consistent procedure, which seems to be related to the interaction picture of quantum mechanics. In this framework we compute the one-loop self-energy for a space/time non-commutative φ 4 theory. Although in all intermediate steps only three-momenta play a role, the final result is manifestly Lorentz covariant and agrees with the naive calculation. Deriving the Feynman rules for general graphs, we show, however, that such a picture holds for tadpole lines only. (orig.)

Combinatorial commutative algebra

CERN Document Server

Miller, Ezra

2005-01-01

Offers an introduction to combinatorial commutative algebra, focusing on combinatorial techniques for multigraded polynomial rings, semigroup algebras, and determined rings. The chapters in this work cover topics ranging from homological invariants of monomial ideals and their polyhedral resolutions, to tools for studying algebraic varieties.

On a question of Herstein concerning commutators in division rings

International Nuclear Information System (INIS)

Mahdavi Hezavehi, M.; Akbari Feyzaabaadi, S.

1995-05-01

Let D be a division ring with centre Z in which for all x not = 0 and y not = 0 in D, (xyx -1 y -1 ) p(x,y) is an element of Z, for some integer p(x,y) ≥ 1, depending on x and y. Given a is an element of D such that a s is an element of Z for some s ≥ 1, it is shown that the minimal polynomial of a over Z is of the form t k - r, where (k,6) = 1. Using this result, it is proved that if p(x,y) is of the form 2 n(x,y) , then D is commutative. (author). 7 refs

Faithfully quadratic rings

CERN Document Server

Dickmann, M

2015-01-01

In this monograph the authors extend the classical algebraic theory of quadratic forms over fields to diagonal quadratic forms with invertible entries over broad classes of commutative, unitary rings where -1 is not a sum of squares and 2 is invertible. They accomplish this by: (1) Extending the classical notion of matrix isometry of forms to a suitable notion of T-isometry, where T is a preorder of the given ring, A, or T = A^2. (2) Introducing in this context three axioms expressing simple properties of (value) representation of elements of the ring by quadratic forms, well-known to hold in

Route Choice Model Based on Game Theory for Commuters

Directory of Open Access Journals (Sweden)

Licai Yang

2016-06-01

Full Text Available The traffic behaviours of commuters may cause traffic congestion during peak hours. Advanced Traffic Information System can provide dynamic information to travellers. Due to the lack of timeliness and comprehensiveness, the provided information cannot satisfy the travellers’ needs. Since the assumptions of traditional route choice model based on Expected Utility Theory conflict with the actual situation, a route choice model based on Game Theory is proposed to provide reliable route choice to commuters in actual situation in this paper. The proposed model treats the alternative routes as game players and utilizes the precision of predicted information and familiarity of traffic condition to build a game. The optimal route can be generated considering Nash Equilibrium by solving the route choice game. Simulations and experimental analysis show that the proposed model can describe the commuters’ routine route choice decisionexactly and the provided route is reliable.

Topological field theories and quantum mechanics on commutative space

International Nuclear Information System (INIS)

Lefrancois, M.

2005-12-01

In particle physics, the Standard Model describes the interactions between fundamental particles. However, it was not able till now to unify quantum field theory and general relativity. This thesis focuses on two different unification approaches, though they might show some compatibility: topological field theories and quantum mechanics on non-commutative space. Topological field theories have been introduced some twenty years ago and have a very strong link to mathematics: their observables are topological invariants of the manifold they are defined on. In this thesis, we first give interest to topological Yang-Mills. We develop a superspace formalism and give a systematic method for the determination of the observables. This approach allows, once projected on a particular super gauge (of Wess-Zumino type), to recover the existing results but it also gives a generalisation to the case of an unspecified super-gauge. We have then be able to show that the up-to-now known observables correspond to the most general form of the solutions. This superspace formalism can be applied to more complex models; the case of topological gravity is given here in example. Quantum mechanics on noncommutative space provides an extension of the Heisenberg algebra of ordinary quantum mechanics. What differs here is that the components of the position or momentum operators do not commute with each other anymore. This implies to introduce a fundamental length. The second part of this thesis focuses on the description of the commutation algebra. Applications are made to low-dimensional quantum systems (Landau system, harmonic oscillator...) and to supersymmetric systems. (author)

On the theory of pre- p-nil -rings | Oduwale | Journal of the Nigerian ...

African Journals Online (AJOL)

Generalizing the concept of p-rings, Abian and Mcworter [1] call an associative and commutative ring R with characteristic p a pre-p-ring if xyy = xyy for every x and y in R. It was proved in [1] that every pre-p-ring R is a direct sum R = B ⊕ N of a p-ring B and a nil ring N, where even xy+2 = 0 for every χ∈N . It was also proved ...

Scattering theory of space-time non-commutative abelian gauge field theory

International Nuclear Information System (INIS)

Rim, Chaiho; Yee, Jaehyung

2005-01-01

The unitary S-matrix for space-time non-commutative quantum electrodynamics is constructed using the *-time ordering which is needed in the presence of derivative interactions. Based on this S-matrix, we formulate the perturbation theory and present the Feynman rule. We then apply this perturbation analysis to the Compton scattering process to the lowest order and check the gauge invariance of the scattering amplitude at this order.

Algebraic K-theory of generalized schemes

DEFF Research Database (Denmark)

Anevski, Stella Victoria Desiree

and geometry over the field with one element. It also permits the construction of important Arakelov theoretical objects, such as the completion \\Spec Z of Spec Z. In this thesis, we prove a projective bundle theorem for the eld with one element and compute the Chow rings of the generalized schemes Sp\\ec ZN......Nikolai Durov has developed a generalization of conventional scheme theory in which commutative algebraic monads replace commutative unital rings as the basic algebraic objects. The resulting geometry is expressive enough to encompass conventional scheme theory, tropical algebraic geometry......, appearing in the construction of \\Spec Z....

Non-commutative analysis

CERN Document Server

Jorgensen, Palle

2017-01-01

The book features new directions in analysis, with an emphasis on Hilbert space, mathematical physics, and stochastic processes. We interpret 'non-commutative analysis' broadly to include representations of non-Abelian groups, and non-Abelian algebras; emphasis on Lie groups and operator algebras (C* algebras and von Neumann algebras.)A second theme is commutative and non-commutative harmonic analysis, spectral theory, operator theory and their applications. The list of topics includes shift invariant spaces, group action in differential geometry, and frame theory (over-complete bases) and their applications to engineering (signal processing and multiplexing), projective multi-resolutions, and free probability algebras.The book serves as an accessible introduction, offering a timeless presentation, attractive and accessible to students, both in mathematics and in neighboring fields.

Constraints on effective Lagrangian of D-branes from non-commutative gauge theory

International Nuclear Information System (INIS)

Okawa, Yuji; Terashima, Seiji

2000-01-01

It was argued that there are two different descriptions of the effective Lagrangian of gauge fields on D-branes by non-commutative gauge theory and by ordinary gauge theory in the presence of a constant B field background. In the case of bosonic string theory, however, it was found in the previous works that the two descriptions are incompatible under the field redefinition which relates the non-commutative gauge field to the ordinary one found by Seiberg and Witten. In this paper we resolve this puzzle to observe the necessity of gauge-invariant but B-dependent correction terms involving metric in the field redefinition which have not been considered before. With the problem resolved, we establish a systematic method under the α' expansion to derive the constraints on the effective Lagrangian imposed by the compatibility of the two descriptions where the form of the field redefinition is not assumed

Lieb-Robinson bounds for multi-commutators and applications to response theory

CERN Document Server

Bru, J -B

2017-01-01

Lieb-Robinson bounds for multi-commutators are effective mathematical tools to handle analytic aspects of infinite volume dynamics of non-relativistic quantum particles with short-range, possibly time-dependent interactions. In particular, the existence of fundamental solutions is shown for those (non-autonomous) C*-dynamical systems for which the usual conditions found in standard theories of (parabolic or hyperbolic) non-autonomous evolution equations are not given. In mathematical physics, bounds on multi-commutators of an order higher than two can be used to study linear and non-linear responses of interacting particles to external perturbations. These bounds are derived for lattice fermions, in view of applications to microscopic quantum theory of electrical conduction discussed in this book. All results also apply to quantum spin systems, with obvious modifications. In order to make the results accessible to a wide audience, in particular to students in mathematics with little Physics background, basics...

Non(anti)commutative gauge theories in harmonic superspace

International Nuclear Information System (INIS)

Quevedo Z., L.E.

2006-01-01

In this work we study the properties of non-singlet Q-deformed N=2 supersymmetric gauge theories, from a field-theoretical point of view. Starting from the supersymmetry breaking pattern induced by a general deformation matrix, we embark on the construction of the non-singlet deformed gauge transformation laws for all vector multiplet fields and their corresponding minimal Seiberg-Witten map. Several deformes super-Yang-Mills actions in components corresponding to different choices of the non-singlet deformation tensor are built. For a particular decomposition ansats of such tensor, we obtain exact actions describing the bosonic sector of the deformed N=(1,0) and the full action for enhances N=(1,1/2) residual supersymmetry. A tuned supersymmetry breaking of this enhanced action down to the N=(1,0) case is found by weakly restoring some discarded degrees of freedom of the deformation. Finally we find the associated residual supersymmetry transformations for the cases studied. The first part of this work, gives an overview of noncommutativity in quantum field theory and of harmonic superspace as needed to define noncommutative generalizations of extended gauge field theories. A study of general properties of non(anti)commutative structures in N=2 euclidean superspace and the (super)symmetry breaking pattern induced by Q-deformations follows. in addition, singlet-deformed super-Yang-Mills is given as an example. The second part deals with non-singlet Q-deformations of gauge theories. We introduce a decomposition ansatz for the deformation matrix, allowing an exact study of the deformed gauge transformations, and develop a general algorithm to solve the harmonic equations associated to this decomposition. A close expression for the gauge transformations of component fields is derived, along with the corresponding minimal Seiberg-Witten map to an equivalent commutative gauge theory. Finally we build deformed super-Yang-Mills actions and their corresponding

Wages and commuting

DEFF Research Database (Denmark)

Mulalic, Ismir; Ommeren, Jos N. van; Pilegaard, Ninette

2011-01-01

We examine the causal effect of commuting distance on workers' wages in a quasi-natural experiments setting using information on all workers in Denmark. We account for endogeneity of distance by using changes in distance that are due to firms’ relocations. For the range of commuting distances where...... income tax reductions associated with commuting do not apply, one kilometre increase in commuting distance induces a wage increase of about 0.42%, suggesting an hourly compensation of about half of the hourly net wage. Our findings are consistent with wage bargaining theory and suggest a bargaining power...

Area-preserving diffeomorphisms in gauge theory on a non-commutative plane. A lattice study

International Nuclear Information System (INIS)

Bietenholz, W.; Bigarini, A.; INFN, Sezione di Perugia; Humboldt-Universitaet, Berlin; Torrielli, A.

2007-06-01

We consider Yang-Mills theory with the U(1) gauge group on a non-commutative plane. Perturbatively it was observed that the invariance of this theory under area-preserving diffeomorphisms (APDs) breaks down to a rigid subgroup SL(2,R). Here we present explicit results for the APD symmetry breaking at finite gauge coupling and finite non-commutativity. They are based on lattice simulations and measurements of Wilson loops with the same area but with a variety of different shapes. Our results confirm the expected loss of invariance under APDs. Moreover, they strongly suggest that non-perturbatively the SL(2,R) symmetry does not persist either. (orig.)

The Poincaré series of a local Gorenstein ring of multiplicity up to 10 ...

Indian Academy of Sciences (India)

As a by-product we prove the rationality of PR for all local, Gorenstein rings of multiplicity at most ..... Due to the choice of α4,...,αn we have. ∑n i=4 αiβi,j ∈ M. Thus aaj ..... [Ma] Matsumura H, Commutative ring theory (Univ. Press: Cambridge) ...

Distances in zero-divisor and total graphs from commutative rings–A survey

Directory of Open Access Journals (Sweden)

T. Tamizh Chelvam

2016-12-01

Full Text Available There are so many ways to construct graphs from algebraic structures. Most popular constructions are Cayley graphs, commuting graphs and non-commuting graphs from finite groups and zero-divisor graphs and total graphs from commutative rings. For a commutative ring R with non-zero identity, we denote the set of zero-divisors and unit elements of R by Z(R and U(R, respectively. One of the associated graphs to a ring R is the zero-divisor graph; it is a simple graph with vertex set Z(R∖{0}, and two vertices x and y are adjacent if and only if xy=0. This graph was first introduced by Beck, where all the elements of R are considered as the vertices. Anderson and Badawi, introduced the total graph of R, as the simple graph with all elements of R as vertices, and two distinct vertices x and y are adjacent if and only if x+y∈Z(R. For a given graph G, the concept of connectedness, diameter and girth are always of great interest. Several authors extensively studied about the zero-divisor and total graphs from commutative rings. In this paper, we present a survey of results obtained with regard to distances in zero-divisor and total graphs.

Non-commutative standard model: model building

CERN Document Server

Chaichian, Masud; Presnajder, P

2003-01-01

A non-commutative version of the usual electro-weak theory is constructed. We discuss how to overcome the two major problems: (1) although we can have non-commutative U(n) (which we denote by U sub * (n)) gauge theory we cannot have non-commutative SU(n) and (2) the charges in non-commutative QED are quantized to just 0,+-1. We show how the latter problem with charge quantization, as well as with the gauge group, can be resolved by taking the U sub * (3) x U sub * (2) x U sub * (1) gauge group and reducing the extra U(1) factors in an appropriate way. Then we proceed with building the non-commutative version of the standard model by specifying the proper representations for the entire particle content of the theory, the gauge bosons, the fermions and Higgs. We also present the full action for the non-commutative standard model (NCSM). In addition, among several peculiar features of our model, we address the inherentCP violation and new neutrino interactions. (orig.)

Towards a differentiated understanding of active travel behaviour: using social theory to explore everyday commuting.

Science.gov (United States)

Guell, C; Panter, J; Jones, N R; Ogilvie, D

2012-07-01

Fostering physical activity is an established public health priority for the primary prevention of a variety of chronic diseases. One promising population approach is to seek to embed physical activity in everyday lives by promoting walking and cycling to and from work ('active commuting') as an alternative to driving. Predominantly quantitative epidemiological studies have investigated travel behaviours, their determinants and how they may be changed towards more active choices. This study aimed to depart from narrow behavioural approaches to travel and investigate the social context of commuting with qualitative social research methods. Within a social practice theory framework, we explored how people describe their commuting experiences and make commuting decisions, and how travel behaviour is embedded in and shaped by commuters' complex social worlds. Forty-nine semi-structured interviews and eighteen photo-elicitation interviews with accompanying field notes were conducted with a subset of the Commuting and Health in Cambridge study cohort, based in the UK. The findings are discussed in terms of three particularly pertinent facets of the commuting experience. Firstly, choice and decisions are shaped by the constantly changing and fluid nature of commuters' social worlds. Secondly, participants express ambiguities in relation to their reasoning, ambitions and identities as commuters. Finally, commuting needs to be understood as an embodied and emotional practice. With this in mind, we suggest that everyday decision-making in commuting requires the tactical negotiation of these complexities. This study can help to explain the limitations of more quantitative and static models and frameworks in predicting travel behaviour and identify future research directions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Trace Dynamics and a non-commutative special relativity

International Nuclear Information System (INIS)

Lochan, Kinjalk; Singh, T.P.

2011-01-01

Trace Dynamics is a classical dynamical theory of non-commuting matrices in which cyclic permutation inside a trace is used to define the derivative with respect to an operator. We use the methods of Trace Dynamics to construct a non-commutative special relativity. We define a line-element using the Trace over space-time coordinates which are assumed to be operators. The line-element is shown to be invariant under standard Lorentz transformations, and is used to construct a non-commutative relativistic dynamics. The eventual motivation for constructing such a non-commutative relativity is to relate the statistical thermodynamics of this classical theory to quantum mechanics. -- Highlights: → Classical time is external to quantum mechanics. → This implies need for a formulation of quantum theory without classical time. → A starting point could be a non-commutative special relativity. → Such a relativity is developed here using the theory of Trace Dynamics. → A line-element is defined using the Trace over non-commuting space-time operators.

Testing Non-commutative QED, Constructing Non-commutative MHD

OpenAIRE

Guralnik, Z.; Jackiw, R.; Pi, S. Y.; Polychronakos, A. P.

2001-01-01

The effect of non-commutativity on electromagnetic waves violates Lorentz invariance: in the presence of a background magnetic induction field b, the velocity for propagation transverse to b differs from c, while propagation along b is unchanged. In principle, this allows a test by the Michelson-Morley interference method. We also study non-commutativity in another context, by constructing the theory describing a charged fluid in a strong magnetic field, which forces the fluid particles into ...

Open branes in space-time non-commutative little string theory

International Nuclear Information System (INIS)

Harmark, T.

2001-01-01

We conjecture the existence of two new non-gravitational six-dimensional string theories, defined as the decoupling limit of NS5-branes in the background of near-critical electrical two- and three-form RR fields. These theories are space-time non-commutative Little String Theories with open branes. The theory with (2,0) supersymmetry has an open membrane in the spectrum and reduces to OM theory at low energies. The theory with (1,1) supersymmetry has an open string in the spectrum and reduces to (5+1)-dimensional NCOS theory for weak NCOS coupling and low energies. The theories are shown to be T-dual with the open membrane being T-dual to the open string. The theories therefore provide a connection between (5+1)-dimensional NCOS theory and OM theory. We study the supergravity duals of these theories and we consider a chain of dualities that shows how the T-duality between the two theories is connected with the S-duality between (4+1)-dimensional NCOS theory and OM theory

Non commutative geometry and super Yang-Mills theory

International Nuclear Information System (INIS)

Bigatti, D.

1999-01-01

We aim to connect the non commutative geometry 'quotient space' viewpoint with the standard super Yang Mills theory approach in the spirit of Connes-Douglas-Schwartz and Douglas-Hull description of application of noncommutative geometry to matrix theory. This will result in a relation between the parameters of a rational foliation of the torus and the dimension of the group U(N). Namely, we will be provided with a prescription which allows to study a noncommutative geometry with rational parameter p/N by means of a U(N) gauge theory on a torus of size Σ/N with the boundary conditions given by a system with p units of magnetic flux. The transition to irrational parameter can be obtained by letting N and p tend to infinity with fixed ratio. The precise meaning of the limiting process will presumably allow better clarification. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Fuzzy commutative algebra and its application in mechanical engineering

International Nuclear Information System (INIS)

Han, J.; Song, H.

1996-01-01

Based on literature data, this paper discusses the whole mathematical structure about point-fuzzy number set F(R). By introducing some new operations about addition, subtraction, multiplication, division and scalar multiplication, we prove that F(R) can form fuzzy linear space, fuzzy commutative ring, fuzzy commutative algebra in order. Furthermore, we get that A is fuzzy commutative algebra for any fuzzy subset. At last, we give an application of point-fuzzy number to mechanical engineering

Strong coupling effects in non-commutative spaces from OM theory and supergravity

International Nuclear Information System (INIS)

Russo, J.G.; Sheikh-Jabbari, M.M.

2000-11-01

We show that a four-parameter class of 3+1 dimensional NCOS theories can be obtained by dimensional reduction on a general 2-torus from OM theory. Compactifying two spatial directions of NCOS theory on a 2-torus, we study the transformation properties under the SO(2,2; Z) T-duality group. We then discuss non-perturbative configurations of non-commutative super Yang-Mills theory. In particular, we calculate the tension for magnetic monopoles and (p,q) dyons and exhibit their six-dimensional origin, and construct a supergravity solution representing an instanton in the gauge theory. We also compute the potential for a monopole-antimonopole in the supergravity approximation. (author)

Hereditary noetherian prime rings and idealizers

CERN Document Server

Levy, Lawrence S

2011-01-01

The direct sum behaviour of its projective modules is a fundamental property of any ring. Hereditary Noetherian prime rings are perhaps the only noncommutative Noetherian rings for which this direct sum behaviour (for both finitely and infinitely generated projective modules) is well-understood, yet highly nontrivial. This book surveys material previously available only in the research literature. It provides a re-worked and simplified account, with improved clarity, fresh insights and many original results about finite length modules, injective modules and projective modules. It culminates in the authors' surprisingly complete structure theorem for projective modules which involves two independent additive invariants: genus and Steinitz class. Several applications demonstrate its utility. The theory, extending the well-known module theory of commutative Dedekind domains and of hereditary orders, develops via a detailed study of simple modules. This relies upon the substantial account of idealizer subrings wh...

Stress-tensor commutators and Schwinger terms in singleton theories

International Nuclear Information System (INIS)

Bergshoeff, E.; Sezgin, E.; Tanii, Y.

1989-06-01

We compute the commutators of the regularized quantum stress-tensor of singleton theories formulated on the boundary of a (p + 2)-dimensional anti de Sitter space (AdS p+2 ). (These are superconformal field theories on S p x S 1 ). We find that the algebra is not closed except in the case of AdS 3 . It does contain, however, the finite dimensional AdS p+2 algebra SO(p + 1,2). We also find divergent, field dependent as well as field independent Schwinger terms (i.e. the central extensions), which, however, do not lead to anomalies in the algebra of the AdS charges. We also give a simple derivation of the two-point functions for bosonic and fermionic singletons. (author). 15 refs

Covariant non-commutative space–time

Directory of Open Access Journals (Sweden)

Jonathan J. Heckman

2015-05-01

Full Text Available We introduce a covariant non-commutative deformation of 3+1-dimensional conformal field theory. The deformation introduces a short-distance scale ℓp, and thus breaks scale invariance, but preserves all space–time isometries. The non-commutative algebra is defined on space–times with non-zero constant curvature, i.e. dS4 or AdS4. The construction makes essential use of the representation of CFT tensor operators as polynomials in an auxiliary polarization tensor. The polarization tensor takes active part in the non-commutative algebra, which for dS4 takes the form of so(5,1, while for AdS4 it assembles into so(4,2. The structure of the non-commutative correlation functions hints that the deformed theory contains gravitational interactions and a Regge-like trajectory of higher spin excitations.

Supersymmetric rings in field theory

International Nuclear Information System (INIS)

Blanco-Pillado, Jose J.; Redi, Michele

2006-01-01

We study the dynamics of BPS string-like objects obtained by lifting monopole and dyon solutions of N = 2 Super-Yang-Mills theory to five dimensions. We present exact traveling wave solutions which preserve half of the supersymmetries. Upon compactification this leads to macroscopic BPS rings in four dimensions in field theory. Due to the fact that the strings effectively move in six dimensions the same procedure can also be used to obtain rings in five dimensions by using the hidden dimension

Application of commutator theorems to the integration of representations of Lie algebras and commutation relations

International Nuclear Information System (INIS)

Froehlich, J.

1977-01-01

Sufficient conditions on unbounded, symmetric operators A and B which imply that exp(itA)exp(isB)exp(-itA) satisfies the well known 'multiple commutator' formula are derived. This formula is then applied to prove new necessary and sufficient conditions for the integrability of representations of Lie algebras and canonical commutation relations and the commutativity of the spectral projections of two commuting, unbounded, self-adjoint operators. A classic theorem of Nelson's is obtained as a corollary. Our results are useful in relativistic quantum field theory. (orig.) [de

Weinberg-Salam theory in non-commutative geometry

International Nuclear Information System (INIS)

Morita, Katsusada; Okumura, Yoshitaka.

1994-01-01

Ordinary differential calculus on smooth manifold is generalized so as to construct gauge theory coupled to fermions on discrete space M 4 xZ 2 which is an underlying space-time in the non-commutative geometry for the standard model. We can reproduce not only the bosonic sector but also the fermionic sector of the Weinberg-Salam theory without recourse to the Dirac operator at the outset. Treatment of the fermionic sector is based on the generalized spinor one-forms from which the Dirac lagrangian is derived through taking the inner product. Two model constructions are presented using our formalism, both giving the classical mass relation m H = √2m w . The first model leaves the Weinberg angle arbitrary as usual, while the second one predicts sin 2 θ w = 1/4 in the tree level. This prediction is the same as that of Connes but we obtain it from correct hypercharge assignment of 2x2 matrix-valued Higgs field and from vanishing photon mass, thereby dispensing with Connes' 0-trace condition or the equivalent. (author)

A non-perturbative study of 4d U(1) non-commutative gauge theory - the fate of one-loop instability

International Nuclear Information System (INIS)

Bietenholz, Wolfgang; Nishimura, Jun; Susaki, Yoshiaki; Volkholz, Jan

2006-01-01

Recent perturbative studies show that in 4d non-commutative spaces, the trivial (classically stable) vacuum of gauge theories becomes unstable at the quantum level, unless one introduces sufficiently many fermionic degrees of freedom. This is due to a negative IR-singular term in the one-loop effective potential, which appears as a result of the UV/IR mixing. We study such a system non-perturbatively in the case of pure U(1) gauge theory in four dimensions, where two directions are non-commutative. Monte Carlo simulations are performed after mapping the regularized theory onto a U(N) lattice gauge theory in d = 2. At intermediate coupling strength, we find a phase in which open Wilson lines acquire non-zero vacuum expectation values, which implies the spontaneous breakdown of translational invariance. In this phase, various physical quantities obey clear scaling behaviors in the continuum limit with a fixed non-commutativity parameter θ, which provides evidence for a possible continuum theory. The extent of the dynamically generated space in the non-commutative directions becomes finite in the above limit, and its dependence on θ is evaluated explicitly. We also study the dispersion relation. In the weak coupling symmetric phase, it involves a negative IR-singular term, which is responsible for the observed phase transition. In the broken phase, it reveals the existence of the Nambu-Goldstone mode associated with the spontaneous symmetry breaking

On the Laurent polynomial rings

International Nuclear Information System (INIS)

Stefanescu, D.

1985-02-01

We describe some properties of the Laurent polynomial rings in a finite number of indeterminates over a commutative unitary ring. We study some subrings of the Laurent polynomial rings. We finally obtain two cancellation properties. (author)

Strong commutativity preserving generalized derivations on ...

African Journals Online (AJOL)

Let R be a non-commutative prime ring of characteristic different from 2, with right Utumi quotient ring U and extended centroid C and let F and G be generalized derivations of R such that F(x)G(y)-F(y)G(x) = [x; y], for all x; y ∈ S, where S is a subset of R. Here we will discuss the following cases: (a) S = [R;R];. b) S = L, where ...

Electron commutator on integrated circuits

International Nuclear Information System (INIS)

Demidenko, V.V.

1975-01-01

The scheme and the parameters of an electron 16-channel contactless commutator based entirely on integrated circuits are described. The device consists of a unit of analog keys based on field-controlled metal-insulator-semiconductor (m.i.s.) transistors, operation amplifier comparators controlling these keys, and a level distributor. The distributor is based on a ''matrix'' scheme and comprises two ring-shaped shift registers plugged in series and a decoder base on two-input logical elements I-NE. The principal dynamical parameters of the circuit are as follows: the control signal delay in the distributor. 50 nsec; the total channel switch-over time, 500-600 nsec. The commutator transmits both constant signals and pulses whose duration reaches tens of nsec. The commutator can be used in data acquisition and processing systems, for shaping complicated signals (for example), (otherwise signals), for simultaneous oscillographing of several signals, and so forth [ru

A non-perturbative study of 4d U(1) non-commutative gauge theory — the fate of one-loop instability

Science.gov (United States)

Bietenholz, Wolfgang; Nishimura, Jun; Susaki, Yoshiaki; Volkholz, Jan

2006-10-01

Recent perturbative studies show that in 4d non-commutative spaces, the trivial (classically stable) vacuum of gauge theories becomes unstable at the quantum level, unless one introduces sufficiently many fermionic degrees of freedom. This is due to a negative IR-singular term in the one-loop effective potential, which appears as a result of the UV/IR mixing. We study such a system non-perturbatively in the case of pure U(1) gauge theory in four dimensions, where two directions are non-commutative. Monte Carlo simulations are performed after mapping the regularized theory onto a U(N) lattice gauge theory in d = 2. At intermediate coupling strength, we find a phase in which open Wilson lines acquire non-zero vacuum expectation values, which implies the spontaneous breakdown of translational invariance. In this phase, various physical quantities obey clear scaling behaviors in the continuum limit with a fixed non-commutativity parameter θ, which provides evidence for a possible continuum theory. The extent of the dynamically generated space in the non-commutative directions becomes finite in the above limit, and its dependence on θ is evaluated explicitly. We also study the dispersion relation. In the weak coupling symmetric phase, it involves a negative IR-singular term, which is responsible for the observed phase transition. In the broken phase, it reveals the existence of the Nambu-Goldstone mode associated with the spontaneous symmetry breaking.

An Identity in Commutative Rings with Unity with Applications to Various Sums of Powers

Directory of Open Access Journals (Sweden)

Miomir Andjić

2017-01-01

Full Text Available Let R=(R,+,· be a commutative ring of characteristic m>0 (m may be equal to +∞ with unity e and zero 0. Given a positive integer n

The shear viscosity of the non-commutative plasma

International Nuclear Information System (INIS)

Landsteiner, Karl; Mas, Javier

2007-01-01

We compute the shear viscosity of the non-commutative N = 4 super Yang-Mills quantum field theory at strong coupling using the dual supergravity background. Special interest derives from the fact that the background presents an intrinsic anisotropy in space through the distinction of commutative and non-commutative directions. Despite this anisotropy the analysis exhibits the ubiquitous result η/s = 1/4π for two different shear channels. In order to derive this result, we show that the boundary energy momentum tensor must couple to the open string metric. As a byproduct we compute the renormalised holographic energy momentum tensor and show that it coincides with one in the commutative theory

Commutative algebra with a view toward algebraic geometry

CERN Document Server

Eisenbud, David

1995-01-01

Commutative Algebra is best understood with knowledge of the geometric ideas that have played a great role in its formation, in short, with a view towards algebraic geometry. The author presents a comprehensive view of commutative algebra, from basics, such as localization and primary decomposition, through dimension theory, differentials, homological methods, free resolutions and duality, emphasizing the origins of the ideas and their connections with other parts of mathematics. Many exercises illustrate and sharpen the theory and extended exercises give the reader an active part in complementing the material presented in the text. One novel feature is a chapter devoted to a quick but thorough treatment of Grobner basis theory and the constructive methods in commutative algebra and algebraic geometry that flow from it. Applications of the theory and even suggestions for computer algebra projects are included. This book will appeal to readers from beginners to advanced students of commutative algebra or algeb...

Topological field theories and quantum mechanics on commutative space; Theories des champs topologiques et mecanique quantique en espace non-commutatif

Energy Technology Data Exchange (ETDEWEB)

Lefrancois, M

2005-12-15

In particle physics, the Standard Model describes the interactions between fundamental particles. However, it was not able till now to unify quantum field theory and general relativity. This thesis focuses on two different unification approaches, though they might show some compatibility: topological field theories and quantum mechanics on non-commutative space. Topological field theories have been introduced some twenty years ago and have a very strong link to mathematics: their observables are topological invariants of the manifold they are defined on. In this thesis, we first give interest to topological Yang-Mills. We develop a superspace formalism and give a systematic method for the determination of the observables. This approach allows, once projected on a particular super gauge (of Wess-Zumino type), to recover the existing results but it also gives a generalisation to the case of an unspecified super-gauge. We have then be able to show that the up-to-now known observables correspond to the most general form of the solutions. This superspace formalism can be applied to more complex models; the case of topological gravity is given here in example. Quantum mechanics on noncommutative space provides an extension of the Heisenberg algebra of ordinary quantum mechanics. What differs here is that the components of the position or momentum operators do not commute with each other anymore. This implies to introduce a fundamental length. The second part of this thesis focuses on the description of the commutation algebra. Applications are made to low-dimensional quantum systems (Landau system, harmonic oscillator...) and to supersymmetric systems. (author)

Interactions Between Representation Ttheory, Algebraic Topology and Commutative Algebra

CERN Document Server

Pitsch, Wolfgang; Zarzuela, Santiago

2016-01-01

This book includes 33 expanded abstracts of selected talks given at the two workshops "Homological Bonds Between Commutative Algebra and Representation Theory" and "Brave New Algebra: Opening Perspectives," and the conference "Opening Perspectives in Algebra, Representations, and Topology," held at the Centre de Recerca Matemàtica (CRM) in Barcelona between January and June 2015. These activities were part of the one-semester intensive research program "Interactions Between Representation Theory, Algebraic Topology and Commutative Algebra (IRTATCA)." Most of the abstracts present preliminary versions of not-yet published results and cover a large number of topics (including commutative and non commutative algebra, algebraic topology, singularity theory, triangulated categories, representation theory) overlapping with homological methods. This comprehensive book is a valuable resource for the community of researchers interested in homological algebra in a broad sense, and those curious to learn the latest dev...

Commuting, Exercise and Sport

DEFF Research Database (Denmark)

Larsen, Jonas

2018-01-01

The uniqueness of this article is that it deals with long-distance bike commuting in pro-cycling Copenhagen and its environs. Informed by practice theory and sensuous studies of urban and sport practices, I discuss the ‘things and environments’, ‘meanings’ and ‘competences and biological bodies......’ that typify long-distance commuter cycling. This article develops cycling literature and the ‘mobilities paradigm’ in the following ways: by outlining a practice approach to cycling; challenging the idea that commuter cycling is only for short distances; undermining the distinction between utility and sport...... cycling; and lastly by connecting the ‘mobilities paradigm’ with literature on active travel and sport studies....

Introduction to Dubois-Violette's non-commutative differential geometry

International Nuclear Information System (INIS)

Djemai, A.E.F.

1994-07-01

In this work, one presents a detailed review of Dubois-Violette et al. approach to non-commutative differential calculus. The non-commutative differential geometry of matrix algebras and the non-commutative Poisson structures are treated in some details. We also present the analog of the Maxwell's theory and the new models of Yang-Mills-Higgs theories that can be constructed in this framework. In particular, some simple models are compared with the standard model. Finally, we discuss some perspectives and open questions. (author). 32 refs

Bjorken-Johnson-Low analysis of commutator anomalies, current-divergence anomalies, and Fujikawa's relation in chiral gauge theories

International Nuclear Information System (INIS)

Seo, K.

1990-01-01

Fermion one-loop corrections to the commutators of the gauge field, the electric field, and the charge density with the total Hamiltonian are evaluated by the Bjorken-Johnson-Low method in chiral gauge theories. It turns out that individual terms of the Hamiltonian give anomalous terms to the commutator with the electric field, but the total Hamiltonian does not. That is, the classical equation of motion for the electric field holds as the Heisenberg equation. The current-divergence anomaly is identified with the anomalous terms of the commutator between the charge density and the total Hamiltonian. These two results are combined to show that the time derivative of the Gauss-law operator amounts to the current-divergence anomaly (Fujikawa's relation)

Non-commutative tomography and signal processing

International Nuclear Information System (INIS)

Mendes, R Vilela

2015-01-01

Non-commutative tomography is a technique originally developed and extensively used by Professors M A Man’ko and V I Man’ko in quantum mechanics. Because signal processing deals with operators that, in general, do not commute with time, the same technique has a natural extension to this domain. Here, a review is presented of the theory and some applications of non-commutative tomography for time series as well as some new results on signal processing on graphs. (paper)

QPFT operator algebras and commutative exterior differential calculus

International Nuclear Information System (INIS)

Yur'ev, D.V.

1993-01-01

The reduction of the structure theory of the operator algebras of quantum projective (sl(2, C)-invariant) field theory (QPFT operator algebras) to a commutative exterior differential calculus by means of the operation of renormalization of a pointwise product of operator fields is described. In the first section, the author introduces the concept of the operator algebra of quantum field theory and describes the operation of the renormalization of a pointwise product of operator fields. The second section is devoted to a brief exposition of the fundamentals of the structure theory of QPT operator algebras. The third section is devoted to commutative exterior differential calculus. In the fourth section, the author establishes the connection between the renormalized pointwise product of operator fields in QPFT operator algebras and the commutative exterior differential calculus. 5 refs

Some homological properties of skew PBW extensions arising in non-commutative algebraic geometry

Directory of Open Access Journals (Sweden)

Lezama Oswaldo

2017-06-01

Full Text Available In this short paper we study for the skew PBW (Poincar-Birkhoff-Witt extensions some homological properties arising in non-commutative algebraic geometry, namely, Auslander-Gorenstein regularity, Cohen-Macaulayness and strongly noetherianity. Skew PBW extensions include a considerable number of non-commutative rings of polynomial type such that classical PBW extensions, quantum polynomial rings, multiplicative analogue of the Weyl algebra, some Sklyanin algebras, operator algebras, diffusion algebras, quadratic algebras in 3 variables, among many others. Parametrization of the point modules of some examples is also presented.

Non-commutative differential calculus and the axial anomaly in Abelian lattice gauge theories

International Nuclear Information System (INIS)

Fujiwara, Takanori; Suzuki, Hiroshi; Wu, Ke

2000-01-01

The axial anomaly in lattice gauge theories has a topological nature when the Dirac operator satisfies the Ginsparg-Wilson relation. We study the axial anomaly in Abelian gauge theories on an infinite hypercubic lattice by utilizing cohomological arguments. The crucial tool in our approach is the non-commutative differential calculus (NCDC) which makes the Leibniz rule of exterior derivatives valid on the lattice. The topological nature of the 'Chern character' on the lattice becomes manifest in the context of NCDC. Our result provides an algebraic proof of Luescher's theorem for a four-dimensional lattice and its generalization to arbitrary dimensions

Some elements of a theory of multidimensional complex variables. I - General theory. II - Expansions of analytic functions and application to fluid flows

Science.gov (United States)

Martin, E. Dale

1989-01-01

The paper introduces a new theory of N-dimensional complex variables and analytic functions which, for N greater than 2, is both a direct generalization and a close analog of the theory of ordinary complex variables. The algebra in the present theory is a commutative ring, not a field. Functions of a three-dimensional variable were defined and the definition of the derivative then led to analytic functions.

Non-commutative covering spaces and their symmetries

DEFF Research Database (Denmark)

Canlubo, Clarisson

dened and its corresponding Galois theory. Using this and basic concepts from algebraic geometryand spectral theory, we will give a full description of the general structure of non-centralcoverings. Examples of coverings of the rational and irrational non-commutative tori will alsobe studied. Using...... will explain this and relate it to bi-Galois theory.Using the OZ-transform, we will show that non-commutative covering spaces come in pairs.Several categories of covering spaces will be dened and studied. Appealing to Tannaka duality,we will explain how this lead to a notion of an etale fundamental group...

On the classical dynamics of charges in non-commutative QED

International Nuclear Information System (INIS)

Fatollahi, A.H.; Mohammadzadeh, H.

2004-01-01

Following Wong's approach to formulating the classical dynamics of charged particles in non-Abelian gauge theories, we derive the classical equations of motion of a charged particle in U(1) gauge theory on non-commutative space, the so-called non-commutative QED. In the present use of the procedure, it is observed that the definition of the mechanical momenta should be modified. The derived equations of motion manifest the previous statement about the dipole behavior of the charges in non-commutative space. (orig.)

Genus of total graphs from rings: A survey

Directory of Open Access Journals (Sweden)

T. Tamizh Chelvam

2018-04-01

Full Text Available Let R be a commutative ring. The total graph T Γ ( R of R is the undirected graph with vertex set R and two distinct vertices x and y are adjacent if x + y is a zero divisor in R . In this paper, we present a survey of results on the genus of T Γ ( R and three of its generalizations. Keywords: Commutative ring, Total graph, Cayley graph, Genus, Planar

Commuting graphs of matrix algebras

International Nuclear Information System (INIS)

Akbari, S.; Bidkhori, H.; Mohammadian, A.

2006-08-01

The commuting graph of a ring R, denoted by Γ(R), is a graph whose vertices are all non- central elements of R and two distinct vertices x and y are adjacent if and only if xy = yx. The commuting graph of a group G, denoted by Γ(G), is similarly defined. In this paper we investigate some graph theoretic properties of Γ(M n (F)), where F is a field and n ≥ 2. Also we study the commuting graphs of some classical groups such as GL n (F) and SL n (F). We show that Γ(M n (F)) is a connected graph if and only if every field extension of F of degree n contains a proper intermediate field. We prove that apart from finitely many fields, a similar result is true for Γ(GL n (F)) and Γ(SL n (F)). Also we show that for two fields E and F and integers m, n ≥> 2, if Γ(M m (E)) ≅ Γ(M n (F)), then m = n and vertical bar E vertical bar = vertical bar F vertical bar. (author)

Computational commutative and non-commutative algebraic geometry

CERN Document Server

Cojocaru, S; Ufnarovski, V

2005-01-01

This publication gives a good insight in the interplay between commutative and non-commutative algebraic geometry. The theoretical and computational aspects are the central theme in this study. The topic is looked at from different perspectives in over 20 lecture reports. It emphasizes the current trends in commutative and non-commutative algebraic geometry and algebra. The contributors to this publication present the most recent and state-of-the-art progresses which reflect the topic discussed in this publication. Both researchers and graduate students will find this book a good source of information on commutative and non-commutative algebraic geometry.

Quantum Fourier Transform Over Galois Rings

OpenAIRE

Zhang, Yong

2009-01-01

Galois rings are regarded as "building blocks" of a finite commutative ring with identity. There have been many papers on classical error correction codes over Galois rings published. As an important warm-up before exploring quantum algorithms and quantum error correction codes over Galois rings, we study the quantum Fourier transform (QFT) over Galois rings and prove it can be efficiently preformed on a quantum computer. The properties of the QFT over Galois rings lead to the quantum algorit...

On computing Gröbner bases in rings of differential operators

Science.gov (United States)

Ma, Xiaodong; Sun, Yao; Wang, Dingkang

2011-05-01

Insa and Pauer presented a basic theory of Groebner basis for differential operators with coefficients in a commutative ring in 1998, and a criterion was proposed to determine if a set of differential operators is a Groebner basis. In this paper, we will give a new criterion such that Insa and Pauer's criterion could be concluded as a special case and one could compute the Groebner basis more efficiently by this new criterion.

Fusion rings and fusion ideals

DEFF Research Database (Denmark)

Andersen, Troels Bak

by the so-called fusion ideals. The fusion rings of Wess-Zumino-Witten models have been widely studied and are well understood in terms of precise combinatorial descriptions and explicit generating sets of the fusion ideals. They also appear in another, more general, setting via tilting modules for quantum......This dissertation investigates fusion rings, which are Grothendieck groups of rigid, monoidal, semisimple, abelian categories. Special interest is in rational fusion rings, i.e., fusion rings which admit a finite basis, for as commutative rings they may be presented as quotients of polynomial rings...

Determinants of long-duration commuting and long-duration commuters' perceptions and attitudes toward commuting time: Evidence from Kunming, China

Directory of Open Access Journals (Sweden)

Mingwei He

2017-04-01

Full Text Available Understanding the commuting patterns of long-duration commuters and the possible changes in these patterns can help policymakers adopt the more reasonable land use and transportation policies. With Kunming in China as a case study, the determinants of long-duration commuting trips were identified based on logistic regression model. The results indicated that age, education level, number of workers, presence of retirees, and residential location have a significant impact on the occurrence of long-duration commuting trips. The ideal commuting times and tolerance thresholds of commuting time of long-duration commuters were also investigated. The statistical results revealed the distributions of ideal commuting times and tolerance thresholds of commuting time of both short- and long-duration commuters. The average tolerance threshold of commuting time and the average ideal commuting time of long-duration commuters were greater than those of short-duration commuters. For 97.2% of the long-duration commuters, their actual commuting time was longer than the ideal commuting time; this finding indicates that most long-duration commuters are dissatisfied with their commuting time. The actual commuting time of 40.1% long-duration commuters exceeded their tolerance thresholds; these commuters are eager to reduce their commuting time.

Categories and Commutative Algebra

CERN Document Server

Salmon, P

2011-01-01

L. Badescu: Sur certaines singularites des varietes algebriques.- D.A. Buchsbaum: Homological and commutative algebra.- S. Greco: Anelli Henseliani.- C. Lair: Morphismes et structures algebriques.- B.A. Mitchell: Introduction to category theory and homological algebra.- R. Rivet: Anneaux de series formelles et anneaux henseliens.- P. Salmon: Applicazioni della K-teoria all'algebra commutativa.- M. Tierney: Axiomatic sheaf theory: some constructions and applications.- C.B. Winters: An elementary lecture on algebraic spaces.

Take part in the Commute-Another-Way Challenge!

CERN Multimedia

CERN Bulletin

2015-01-01

Ring the changes on Thursday, 4 June by commuting another way! CERN has signed up for the 5th “challenge mobilité Rhône-Alpes”, the aim of which is to encourage people to use modes of transport other than their car to get to work. Are you up for the challenge?   Join in the challenge! Sign up using the dedicated CERN form. "Commute another way!" is an initiative launched by the Rhône-Alpes regional authorities and the French environment agency ADEME (l’Agence de l’environnement et de la maîtrise de l’énergie française) to promote alternative ways of travelling to work than the car (excluding carpooling), in private and public-sector organisations across the region. We love this idea and CERN has been signed up to a similar scheme - Bike to Work - for several years. That’s why we’ve decided that CERN should join the Commute-A...

Theory of ring formation around Be stars

International Nuclear Information System (INIS)

Huang, S.S.

1976-01-01

A quantitative theory has been developed for the formation of the gaseous rings around Be stars based on the ideas, first discussed by Gerasimovic, later developed by Huang, and independently suggested by Massa. The theory has been derived from the laws of conservation of energy and angular momentum without any other assumptions

Kleinian singularities and the ground ring of c=1 string theory

International Nuclear Information System (INIS)

Ghoshal, D.; Jatkar, D.P.; Mukhi, S.

1993-01-01

We investigate the nature of the ground ring of c=1 string theory at the special ADE points in the c=1 moduli space associated to discrete subgroups of SU(2). The chiral ground rings at these points are shown to define the ADE series of singular varieties introduced by Klein. The non-chiral ground rings relevant to closed-string theory are 3 real dimensional singular varieties obtained as U(1) quotients of the kleinian varieties. The unbroken symmetries of the theory at these points are the volume-preserving diffeomorphisms of these varieties. The theory of kleinian singularities has a close relation to that of complex hyperKaehler surfaces, or gravitational instantons. We speculate on the relevance of these instantons and of self-dual gravity in c=1 string theory. (orig.)

A generalization of zero divisor graphs associated to commutative ...

Indian Academy of Sciences (India)

M. Afkhami

2018-03-19

Mar 19, 2018 ... R . We also determine all isomorphic classes of finite commutative rings whose generalized zero divisor graphs have genus at most three. Keywords. Zero divisor graph; lower triangular matrix; genus; complete graph. 2010 Mathematics Subject Classification. 15B33, 05C10, 05C25, 05C45. 1. Introduction.

Chiral rings and anomalies in supersymmetric gauge theory

International Nuclear Information System (INIS)

Cachazo, Freddy; Witten, Edward; Seiberg, Nathan; Douglas, Michael R.

2002-01-01

Motivated by recent work of Dijkgraaf and Vafa, we study anomalies and the chiral ring structure in a supersymmetric U(N) gauge theory with an adjoint chiral superfield and an arbitrary superpotential. A certain generalization of the Konishi anomaly leads to an equation which is identical to the loop equation of a bosonic matrix model. This allows us to solve for the expectation values of the chiral operators as functions of a finite number of 'integration constants'. From this, we can derive the Dijkgraaf-Vafa relation of the effective superpotential to a matrix model. Some of our results are applicable to more general theories. For example, we determine the classical relations and quantum deformations of the chiral ring of N=1 super Yang-Mills theory with SU(N) gauge group, showing, as one consequence, that all supersymmetric vacua of this theory have a nonzero chiral condensate. (author)

Fusion Rings for Quantum Groups

DEFF Research Database (Denmark)

Andersen, Henning Haahr; Stroppel, Catharina

2014-01-01

We study the fusion rings of tilting modules for a quantum group at a root of unity modulo the tensor ideal of negligible tilting modules. We identify them in type A with the combinatorial rings from Korff, C., Stroppel, C.: The sl(ˆn)k-WZNW fusion ring: a combinato-rial construction...... and a realisation as quotient of quantum cohomology. Adv. Math. 225(1), 200–268, (2010) and give a similar description of the sp2n-fusion ring in terms of non-commutative symmetric functions. Moreover we give a presentation of all fusion rings in classical types as quotients of polynomial rings. Finally we also...... compute the fusion rings for type G2....

SMARANDACHE NON-ASSOCIATIVE RINGS

OpenAIRE

Vasantha, Kandasamy

2002-01-01

An associative ring is just realized or built using reals or complex; finite or infinite by defining two binary operations on it. But on the contrary when we want to define or study or even introduce a non-associative ring we need two separate algebraic structures say a commutative ring with 1 (or a field) together with a loop or a groupoid or a vector space or a linear algebra. The two non-associative well-known algebras viz. Lie algebras and Jordan algebras are mainly built using a vecto...

Uniquely Strongly Clean Group Rings

Institute of Scientific and Technical Information of China (English)

WANG XIU-LAN

2012-01-01

A ring R is called clean if every element is the sum of an idempotent and a unit,and R is called uniquely strongly clean (USC for short) if every element is uniquely the sum of an idempotent and a unit that commute.In this article,some conditions on a ring R and a group G such that RG is clean are given.It is also shown that if G is a locally finite group,then the group ring RG is USC if and only if R is USC,and G is a 2-group.The left uniquely exchange group ring,as a middle ring of the uniquely clean ring and the USC ring,does not possess this property,and so does the uniquely exchange group ring.

Anomalous commutator of gauge group generators in a non-Abelian chiral theory

International Nuclear Information System (INIS)

Jo, S.

1985-01-01

This paper discusses commutators among non-Abelian fermion currents that are calculated using the BJL limit. It is observed that the gauge dependence of the fermion current with fixed canonical variables should be different from the covariant seagull in order to have correct anomalous commutators

Twin ''Fano-Snowflakes'' over the Smallest Ring of Ternions

Directory of Open Access Journals (Sweden)

Metod Saniga

2008-06-01

Full Text Available Given a finite associative ring with unity, R, any free (left cyclic submodule (FCS generated by a unimodular (n + 1-tuple of elements of R represents a point of the n-dimensional projective space over R. Suppose that R also features FCSs generated by (n + 1-tuples that are not unimodular: what kind of geometry can be ascribed to such FCSs? Here, we (partially answer this question for n = 2 when R is the (unique non-commutative ring of order eight. The corresponding geometry is dubbed a ''Fano-Snowflake'' due to its diagrammatic appearance and the fact that it contains the Fano plane in its center. There exist, in fact, two such configurations – each being tied to either of the two maximal ideals of the ring – which have the Fano plane in common and can, therefore, be viewed as twins. Potential relevance of these noteworthy configurations to quantum information theory and stringy black holes is also outlined.

Non-commutative algebra of functions of 4-dimensional quantum Hall droplet

International Nuclear Information System (INIS)

Chen Yixin; Hou Boyu; Hou Boyuan

2002-01-01

We develop the description of non-commutative geometry of the 4-dimensional quantum Hall fluid's theory proposed recently by Zhang and Hu. The non-commutative structure of fuzzy S 4 , which is the base of the bundle S 7 obtained by the second Hopf fibration, i.e., S 7 /S 3 =S 4 , appears naturally in this theory. The fuzzy monopole harmonics, which are the essential elements in the non-commutative algebra of functions on S 4 , are explicitly constructed and their obeying the matrix algebra is obtained. This matrix algebra is associative. We also propose a fusion scheme of the fuzzy monopole harmonics of the coupling system from those of the subsystems, and determine the fusion rule in such fusion scheme. By products, we provide some essential ingredients of the theory of SO(5) angular momentum. In particular, the explicit expression of the coupling coefficients, in the theory of SO(5) angular momentum, are given. We also discuss some possible applications of our results to the 4-dimensional quantum Hall system and the matrix brane construction in M-theory

On θ-commutators and the corresponding non-commuting graphs

Directory of Open Access Journals (Sweden)

Shalchi S.

2017-12-01

Full Text Available The θ-commutators of elements of a group with respect to an automorphism are introduced and their properties are investigated. Also, corresponding to θ-commutators, we define the θ-non-commuting graphs of groups and study their correlations with other notions. Furthermore, we study independent sets in θ-non-commuting graphs, which enable us to evaluate the chromatic number of such graphs.

Perspective: Ring-polymer instanton theory

Science.gov (United States)

Richardson, Jeremy O.

2018-05-01

Since the earliest explorations of quantum mechanics, it has been a topic of great interest that quantum tunneling allows particles to penetrate classically insurmountable barriers. Instanton theory provides a simple description of these processes in terms of dominant tunneling pathways. Using a ring-polymer discretization, an efficient computational method is obtained for applying this theory to compute reaction rates and tunneling splittings in molecular systems. Unlike other quantum-dynamics approaches, the method scales well with the number of degrees of freedom, and for many polyatomic systems, the method may provide the most accurate predictions which can be practically computed. Instanton theory thus has the capability to produce useful data for many fields of low-temperature chemistry including spectroscopy, atmospheric and astrochemistry, as well as surface science. There is however still room for improvement in the efficiency of the numerical algorithms, and new theories are under development for describing tunneling in nonadiabatic transitions.

Optimization of polynomials in non-commuting variables

CERN Document Server

Burgdorf, Sabine; Povh, Janez

2016-01-01

This book presents recent results on positivity and optimization of polynomials in non-commuting variables. Researchers in non-commutative algebraic geometry, control theory, system engineering, optimization, quantum physics and information science will find the unified notation and mixture of algebraic geometry and mathematical programming useful. Theoretical results are matched with algorithmic considerations; several examples and information on how to use NCSOStools open source package to obtain the results provided. Results are presented on detecting the eigenvalue and trace positivity of polynomials in non-commuting variables using Newton chip method and Newton cyclic chip method, relaxations for constrained and unconstrained optimization problems, semidefinite programming formulations of the relaxations and finite convergence of the hierarchies of these relaxations, and the practical efficiency of algorithms.

Non-commutative and commutative vacua effects in a scalar torsion scenario

Energy Technology Data Exchange (ETDEWEB)

Sheikhahmadi, Haidar, E-mail: h.sh.ahmadi@gmail.com [Department of Physics, Faculty of Science, University of Kurdistan, Sanandaj (Iran, Islamic Republic of); Aghamohammadi, Ali, E-mail: a.aghamohamadi@iausdj.ac.ir [Sanandaj Branch, Islamic Azad University, Sanandaj (Iran, Islamic Republic of); Saaidi, Khaled, E-mail: ksaaidi@uok.ac.ir [Department of Physics, Faculty of Science, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

2015-10-07

In this work, the effects of non-commutative and commutative vacua on the phase space generated by a scalar field in a scalar torsion scenario are investigated. For both classical and quantum regimes, the commutative and non-commutative cases are compared. To take account the effects of non-commutativity, two well known non-commutative parameters, θ and β, are introduced. It should be emphasized, the effects of β which is related to momentum sector has more key role in comparison to θ which is related to space sector. Also the different boundary conditions and mathematical interpretations of non-commutativity are explored.

Non-commutative and commutative vacua effects in a scalar torsion scenario

International Nuclear Information System (INIS)

Sheikhahmadi, Haidar; Aghamohammadi, Ali; Saaidi, Khaled

2015-01-01

In this work, the effects of non-commutative and commutative vacua on the phase space generated by a scalar field in a scalar torsion scenario are investigated. For both classical and quantum regimes, the commutative and non-commutative cases are compared. To take account the effects of non-commutativity, two well known non-commutative parameters, θ and β, are introduced. It should be emphasized, the effects of β which is related to momentum sector has more key role in comparison to θ which is related to space sector. Also the different boundary conditions and mathematical interpretations of non-commutativity are explored.

Non-commutative and commutative vacua effects in a scalar torsion scenario

Directory of Open Access Journals (Sweden)

Haidar Sheikhahmadi

2015-10-01

Full Text Available In this work, the effects of non-commutative and commutative vacua on the phase space generated by a scalar field in a scalar torsion scenario are investigated. For both classical and quantum regimes, the commutative and non-commutative cases are compared. To take account the effects of non-commutativity, two well known non-commutative parameters, θ and β, are introduced. It should be emphasized, the effects of β which is related to momentum sector has more key role in comparison to θ which is related to space sector. Also the different boundary conditions and mathematical interpretations of non-commutativity are explored.

a generalization of zero divisor graphs associated to commutative

Indian Academy of Sciences (India)

8

R is isomorphic to the zero divisor graph Γ(R), and so Γn. R is a generalization of Γ(R) which is called a generalized zero divisor graph of R. In this paper, we study some basic properties of Γn. R. We also determine all isomorphic classes of finite commutative rings whose generalized zero divisor graphs have genus at most ...

Some phenomenological consequences of the time-ordered perturbation theory of QED on non-commutative spacetime

CERN Document Server

Liao, Y

2003-01-01

A framework was recently proposed for doing perturbation theory on non-commutative (NC) spacetime. It preserves the unitarity of the S matrix and differs from the naive, popular approach already at the lowest order in perturbation when time does not commute with space. In this work, we investigate its phenomenological implications at linear colliders, especially the TESLA at DESY, through the processes of e sup + e sup --> mu sup +mu sup - ,H sup + H sup - ,H sup 0 H sup 0. We find that some NC effects computed previously are now modified and that there are new processes which now exhibit NC effects. Indeed, the first two processes get corrected at tree level as opposed to the null result in the naive approach, while the third one coincides with the naive result only in the low energy limit. The impact of the earth's rotation is incorporated. The NC signals are generally significant when the NC scale is comparable to the collider energy. If this is not the case, the non-trivial azimuthal angle distribution an...

Non-commutative geometry and supersymmetry 2

International Nuclear Information System (INIS)

Hussain, F.; Thompson, G.

1991-05-01

Following the general construction of supersymmetric models, the model based on the idea of non-commutative geometry is formulated as a Yang-Mills theory of the graded Lie algebra U(2/1) over a graded space-time manifold. 4 refs

The M5-brane and non-commutative open strings

NARCIS (Netherlands)

Bergshoeff, E.; Berman, D.S.; Schaar, J.P. van der; Sundell, P.

2001-01-01

The M-theory origin of non-commutative open-string theory is examined by investigating the M-theory 5-brane at near critical field strength. In particular, it is argued that the open-membrane metric provides the appropriate moduli when calculating the duality relations between M and II

An Engel condition with an additive mapping in semiprime rings

Indian Academy of Sciences (India)

Banach algebra (for example, C∗ algebra) is semiprime, this purely algebraic result might be of some interest from functional analysis point of view. Keywords. Prime ring; semiprime ring; additive mapping; derivation; commuting mapping; centralizing mapping; functional identity. 2010 Mathematics Subject Classification.

Non-commutative Nash inequalities

International Nuclear Information System (INIS)

Kastoryano, Michael; Temme, Kristan

2016-01-01

A set of functional inequalities—called Nash inequalities—are introduced and analyzed in the context of quantum Markov process mixing. The basic theory of Nash inequalities is extended to the setting of non-commutative L p spaces, where their relationship to Poincaré and log-Sobolev inequalities is fleshed out. We prove Nash inequalities for a number of unital reversible semigroups

Translation invariance, commutation relations and ultraviolet/infrared mixing

International Nuclear Information System (INIS)

Galluccio, Salvatore; Lizzi, Fedele; Vitale, Patrizia

2009-01-01

We show that the Ultraviolet/Infrared mixing of noncommutative field theories with the Groenewold-Moyal product, whereby some (but not all) ultraviolet divergences become infrared, is a generic feature of translationally invariant associative products. We find, with an explicit calculation that the phase appearing in the nonplanar diagrams is the one given by the commutator of the coordinates, the semiclassical Poisson structure of the non commutative spacetime. We do this with an explicit calculation for represented generic products.

On the linearization of nonlinear supersymmetry based on the commutator algebra

Energy Technology Data Exchange (ETDEWEB)

Tsuda, Motomu, E-mail: tsuda@sit.ac.jp

2017-01-10

We discuss a linearization procedure of nonlinear supersymmetry (NLSUSY) based on the closure of the commutator algebra for variations of functionals of Nambu–Goldstone fermions and their derivative terms under NLSUSY transformations in Volkov–Akulov NLSUSY theory. In the case of a set of bosonic and fermionic functionals, which leads to (massless) vector linear supermultiplets, we explicitly show that general linear SUSY transformations of basic components defined from those functionals are uniquely determined by examining the commutation relation in the NLSUSY theory.

Chiral-Yang-Mills theory, non commutative differential geometry, and the need for a Lie super-algebra

International Nuclear Information System (INIS)

Thierry-Mieg, Jean

2006-01-01

In Yang-Mills theory, the charges of the left and right massless Fermions are independent of each other. We propose a new paradigm where we remove this freedom and densify the algebraic structure of Yang-Mills theory by integrating the scalar Higgs field into a new gauge-chiral 1-form which connects Fermions of opposite chiralities. Using the Bianchi identity, we prove that the corresponding covariant differential is associative if and only if we gauge a Lie-Kac super-algebra. In this model, spontaneous symmetry breakdown naturally occurs along an odd generator of the super-algebra and induces a representation of the Connes-Lott non commutative differential geometry of the 2-point finite space

Emergent classicality via commuting position and momentum operators

Energy Technology Data Exchange (ETDEWEB)

Halliwell, J J, E-mail: j.halliwell@ic.ac.u [Blackett Laboratory, Imperial College, London SW7 2BZ (United Kingdom)

2009-06-01

Any account of the emergence of classicality from quantum theory must address the fact that the quantum operators representing positions and momenta do not commute, whereas their classical counterparts suffer no such restrictions. To address this, we revive an old idea of von Neumann, and seek a pair of commuting operators X, P which are, in a specific sense, 'close' to the canonical non-commuting position and momentum operators, x,p. The construction of such operators is related to the problem of finding complete sets of orthonormal phase space localized states, a problem severely limited by the Balian-Low theorem. Here these limitations are avoided by restricting attention to situations in which the density matrix is reasonably decohered (i.e., spread out in phase space).

Commutative $C^*$-algebras and $\\sigma$-normal morphisms

OpenAIRE

de Jeu, Marcel

2003-01-01

We prove in an elementary fashion that the image of a commutative monotone $\\sigma$-complete $C^*$-algebra under a $\\sigma$-normal morphism is again monotone $\\sigma$-complete and give an application of this result in spectral theory.

A multipole-expanded effective field theory for vortex ring-sound interactions

Science.gov (United States)

Garcia-Saenz, Sebastian; Mitsou, Ermis; Nicolis, Alberto

2018-02-01

The low-energy dynamics of a zero temperature superfluid or of the compressional modes of an ordinary fluid can be described by a simple effective theory for a scalar field — the superfluid `phase'. However, when vortex lines are present, to describe all interactions in a local fashion one has to switch to a magnetic-type dual two-form description, which comes with six degrees of freedom (in place of one) and an associated gauge redundancy, and is thus considerably more complicated. Here we show that, in the case of vortex rings and for bulk modes that are much longer than the typical ring size, one can perform a systematic multipole expansion of the effective action and recast it into the simpler scalar field language. In a sense, in the presence of vortex rings the non-single valuedness of the scalar can be hidden inside the rings, and thus out of the reach of the multipole expansion. As an application of our techniques, we compute by standard effective field theory methods the sound emitted by an oscillating vortex ring.

Absence of torsion for NK_1(R) over associative rings

OpenAIRE

Basu, Rabeya

2010-01-01

When R is a commutative ring with identity, and if k is a natural number with kR = R, then C. Weibel proved that SK_1(R[X]) has no k-torsion. We reprove his result for any associative ring R with identity in which kR = R.

Inductive energy storage commutator

International Nuclear Information System (INIS)

Gavrilov, I.M.

1987-01-01

An inductive energy storage commutator is described. The value of commutated current is up to 800 A, the voltage amplitude in the load is up to 50 kV, the working frequency is equal to 1-50 Hz, the commutated power is up to 40 MW. The commutating device comprises of the first stage commutator having two in-series connected modules of the BTSV - 800/235 high-voltage thyristor unit, the second stage commutator containing three GMI-43A parallel connected powerful pulsed triodes, a commutating capacitor, an induction coil, two supplementary high-voltage thyristor keys (20 in-series connected thyristors T2-300 (13 class)), load, control pulse shapers, thyristor keys, power supply

Minimal length uncertainty and generalized non-commutative geometry

International Nuclear Information System (INIS)

Farmany, A.; Abbasi, S.; Darvishi, M.T.; Khani, F.; Naghipour, A.

2009-01-01

A generalized formulation of non-commutative geometry for the Bargmann-Fock space of quantum field theory is presented. The analysis is related to the symmetry of the simplistic space and a minimal length uncertainty.

Substitution of matrices over rings

NARCIS (Netherlands)

Hautus, M.L.J.

1995-01-01

For a given commutative ring with an identity element, we define and study the substitution of a matrix with entries in into a matrix polynomial or rational function over . A Bezout-type remainder theorem and a "partial-substitution rule" are derived and used to obtain a number of results. The

One-loop beta functions for the orientable non-commutative Gross Neveu model TH1"-->

Science.gov (United States)

Lakhoua, A.; Vignes-Tourneret, F.; Wallet, J.-C.

2007-11-01

We compute at the one-loop order the β-functions for a renormalisable non-commutative analog of the Gross Neveu model defined on the Moyal plane. The calculation is performed within the so called x-space formalism. We find that this non-commutative field theory exhibits asymptotic freedom for any number of colors. The β-function for the non-commutative counterpart of the Thirring model is found to be non vanishing.

Wages and commuting: quasi-natural experiments' evidence from firms that relocate

DEFF Research Database (Denmark)

Mulalic, Ismir; Pilegaard, Ninette; van Ommeren, Jos N.

We examine the causal effect of commuting distance on workers' wages in a quasi-natural experiments setting using information on all workers in Denmark. We account for endogeneity of distance by using changes in distance that are due to firms’ relocations. A one kilometre increase in commuting...... distance induces a wage increase of about 0.42%, suggesting an hourly commuting time compensation of 49% of the hourly net wage. Our findings are consistent with wage bargaining theory and due to the experimental setup we are able to exclude many competing explanations of the wage-distance relationship....

Quantum Gibbs Samplers: The Commuting Case

Science.gov (United States)

Kastoryano, Michael J.; Brandão, Fernando G. S. L.

2016-06-01

We analyze the problem of preparing quantum Gibbs states of lattice spin Hamiltonians with local and commuting terms on a quantum computer and in nature. Our central result is an equivalence between the behavior of correlations in the Gibbs state and the mixing time of the semigroup which drives the system to thermal equilibrium (the Gibbs sampler). We introduce a framework for analyzing the correlation and mixing properties of quantum Gibbs states and quantum Gibbs samplers, which is rooted in the theory of non-commutative {mathbb{L}_p} spaces. We consider two distinct classes of Gibbs samplers, one of them being the well-studied Davies generator modelling the dynamics of a system due to weak-coupling with a large Markovian environment. We show that their spectral gap is independent of system size if, and only if, a certain strong form of clustering of correlations holds in the Gibbs state. Therefore every Gibbs state of a commuting Hamiltonian that satisfies clustering of correlations in this strong sense can be prepared efficiently on a quantum computer. As concrete applications of our formalism, we show that for every one-dimensional lattice system, or for systems in lattices of any dimension at temperatures above a certain threshold, the Gibbs samplers of commuting Hamiltonians are always gapped, giving an efficient way of preparing the associated Gibbs states on a quantum computer.

Velocity space ring-plasma instability, magnetized, Part I: Theory

International Nuclear Information System (INIS)

Lee, J.K.; Birdsall, C.K.

1979-01-01

The interaction of magnetized monoenergetic ions (a ring in velocity space) with a homogeneous Maxwellian target plasma is studied numerically using linear Vlasov theory. The ring may be produced when an energetic beam is injected perpendicular to a uniform magnetic field. In addition to yielding the previously known results, the present study classifies this flute-like instability into three distinct regimes based on the beam density relative to the plasma density, where many features such as physical mechanisms, dispersion diagrams, and maximum growth rates are quite different. The effects of electron dynamics, plasma or ring thermal spread, the ratio of ω/sub p//ω/sub c/ for plasma ions, and electromagnetic modifications are also considered

Homotopy theory of modules over diagrams of rings

Directory of Open Access Journals (Sweden)

J. P. C. Greenlees

2014-09-01

Full Text Available Given a diagram of rings, one may consider the category of modules over them. We are interested in the homotopy theory of categories of this type: given a suitable diagram of model categories ℳ( (as runs through the diagram, we consider the category of diagrams where the object ( at comes from ℳ(. We develop model structures on such categories of diagrams and Quillen adjunctions that relate categories based on different diagram shapes. Under certain conditions, cellularizations (or right Bousfield localizations of these adjunctions induce Quillen equivalences. As an application we show that a cellularization of a category of modules over a diagram of ring spectra (or differential graded rings is Quillen equivalent to modules over the associated inverse limit of the rings. Another application of the general machinery here is given in work by the authors on algebraic models of rational equivariant spectra. Some of this material originally appeared in the preprint “An algebraic model for rational torus-equivariant stable homotopy theory”, arXiv:1101.2511, but has been generalized here.

Module theory, extending modules and generalizations

CERN Document Server

Tercan, Adnan

2016-01-01

The main focus of this monograph is to offer a comprehensive presentation of known and new results on various generalizations of CS-modules and CS-rings. Extending (or CS) modules are generalizations of injective (and also semisimple or uniform) modules. While the theory of CS-modules is well documented in monographs and textbooks, results on generalized forms of the CS property as well as dual notions are far less present in the literature. With their work the authors provide a solid background to module theory, accessible to anyone familiar with basic abstract algebra. The focus of the book is on direct sums of CS-modules and classes of modules related to CS-modules, such as relative (injective) ejective modules, (quasi) continuous modules, and lifting modules. In particular, matrix CS-rings are studied and clear proofs of fundamental decomposition results on CS-modules over commutative domains are given, thus complementing existing monographs in this area. Open problems round out the work and establish the...

Understanding the fluid nature of personhood - the ring theory of personhood.

Science.gov (United States)

Radha Krishna, Lalit Kumar; Alsuwaigh, Rayan

2015-03-01

Familial determination, replete with its frequent usurping of patient autonomy, propagation of collusion, and circumnavigation of direct patient involvement in their own care deliberations, continues to impact clinical practice in many Asian nations. Suggestions that underpinning this practice, in Confucian-inspired societies, is the adherence of the populace to the familial centric ideas of personhood espoused by Confucian ethics, provide a novel means of understanding and improving patient-centred care at the end of life. Clinical experience in Confucian-inspired Singapore, however, suggests that personhood is conceived in broader terms. This diverging view inspired a study of local conceptions of personhood and scrutiny of the influence of the family upon it. From the data gathered, a culturally appropriate, clinically relevant and ethically sensitive concept of personhood was proposed: the Ring Theory of Personhood (Ring Theory) that better captures the nuances of local conceptions of personhood. The Ring Theory highlights the fact that, far from being solely dependent upon familial centric ideals, local conceptions of personhood are dynamic, context dependent, evolving ideas delineated by four dimensions. Using the Ring Theory, the nature of familial influences upon the four dimensions of personhood - the Innate, Individual, Relational and Societal - are examined to reveal that, contrary to perceived knowledge, conceptions of personhood within Confucian societies are not the prime reason for the continued presence of this decision-making model but remain present within local thinking and practices as a sociocultural residue and primarily because of inertia in updating ideas. © 2014 John Wiley & Sons Ltd.

Almost commuting self-adjoint matrices: The real and self-dual cases

Science.gov (United States)

Loring, Terry A.; Sørensen, Adam P. W.

2016-08-01

We show that a pair of almost commuting self-adjoint, symmetric matrices is close to a pair of commuting self-adjoint, symmetric matrices (in a uniform way). Moreover, we prove that the same holds with self-dual in place of symmetric and also for paths of self-adjoint matrices. Since a symmetric, self-adjoint matrix is real, we get a real version of Huaxin Lin’s famous theorem on almost commuting matrices. Similarly, the self-dual case gives a version for matrices over the quaternions. To prove these results, we develop a theory of semiprojectivity for real C*-algebras and also examine various definitions of low-rank for real C*-algebras.

Investigating Proenvironmental Behavior: The Case of Commuting Mode Choice

Science.gov (United States)

Trinh, Tu Anh; Phuong Linh Le, Thi

2018-04-01

The central aim of this article is to investigate mode choice behavior among commuters in Ho Chi Minh City using disaggregate mode choice model and norm activation theory. A better understanding of commuters’ choice of transport mode provide an opportunity to obtain valuable information on their travel behaviors which help to build a basic for proffering solutions stimulating commuters to switch to public transport, which in turn contribute to deal with traffic problems and environmental issues. Binary logistic regression was employed under disaggregate choice method. Key findings indicated that Demographic factors including Age (-0.308), Married (-9.089), Weather (-8.272); Trip factors including Travel cost (0.437), Travel distance (0.252), and Norm activation theory (Awareness of consequences: AC2 (-1.699), AC4 (2.951), AC6 (-3.523), AC7 (-2.092), AC9 (-3.045), AC11 (+ 2.939), and Personal norms: PN2 (-2.695)) had strong impact on the commuters’ mode choice. Although motorcycle was the major transport mode among commuters, they presented their willingness to switch to bus transport if it had less negative impacts on the environment and their daily living environment.

Prime divisors and noncommutative valuation theory

CERN Document Server

Marubayashi, Hidetoshi

2012-01-01

Classical valuation theory has applications in number theory and class field theory as well as in algebraic geometry, e.g. in a divisor theory for curves.  But the noncommutative equivalent is mainly applied to finite dimensional skewfields.  Recently however, new types of algebras have become popular in modern algebra; Weyl algebras, deformed and quantized algebras, quantum groups and Hopf algebras, etc. The advantage of valuation theory in the commutative case is that it allows effective calculations, bringing the arithmetical properties of the ground field into the picture.  This arithmetical nature is also present in the theory of maximal orders in central simple algebras.  Firstly, we aim at uniting maximal orders, valuation rings, Dubrovin valuations, etc. in a common theory, the theory of primes of algebras.  Secondly, we establish possible applications of the noncommutative arithmetics to interesting classes of algebras, including the extension of central valuations to nice classes of quantized a...

Determinants of self-employment among commuters and non-commuters

DEFF Research Database (Denmark)

Backman, M.; Karlsson, C.

2016-01-01

We analyse the determinants of self-employment and focus on the contextual environment. By distinguishing between commuters and non-commuters we are able to analyse the influence from the work and home environment, respectively. Our results indicate a significant difference between non...

Lectures on matrix field theory

CERN Document Server

Ydri, Badis

2017-01-01

These lecture notes provide a systematic introduction to matrix models of quantum field theories with non-commutative and fuzzy geometries. The book initially focuses on the matrix formulation of non-commutative and fuzzy spaces, followed by a description of the non-perturbative treatment of the corresponding field theories. As an example, the phase structure of non-commutative phi-four theory is treated in great detail, with a separate chapter on the multitrace approach. The last chapter offers a general introduction to non-commutative gauge theories, while two appendices round out the text. Primarily written as a self-study guide for postgraduate students – with the aim of pedagogically introducing them to key analytical and numerical tools, as well as useful physical models in applications – these lecture notes will also benefit experienced researchers by providing a reference guide to the fundamentals of non-commutative field theory with an emphasis on matrix models and fuzzy geometries.

Do driving restriction policies effectively motivate commuters to use public transportation?

International Nuclear Information System (INIS)

Liu, Yunxia; Hong, Zaisheng; Liu, Yong

2016-01-01

Driving restriction policies have been implemented in some large Chinese cities to cope with severe urban smog pollution. We explored the roles of policy acceptance and other factors in commuters' transport mode decisions, based on the Theory of Planned Behavior. A questionnaire survey was conducted in Tianjin, China. A structural equation model was developed to test eight hypotheses, two of which were rejected. The results indicate that a driving restriction policy alone cannot effectively motivate commuters to use public transport if the policymakers fail to improve public transport, enhance commuters' awareness of consequences, increase commuters' perceived behavior control, and encourage car owners to change driving behavior. Comparisons between car owners and non-owners indicated that car owners view driving restriction policy and public transport more negatively. These negative views could be a barrier for the promotion of public transport among car owners. In addition, attitude toward public transport was found to have positive correlation with commuting time. - Highlights: • Attitude towards public transport has an impact on policy acceptance. • Driving habit indirectly affects policy acceptance and perceived behavior control. • Driving restriction policy and public transport are not popular among car owners. • Attitude towards public transport correlates positively with commuting time.

Rotating ring-ring electrode theory and experiment

NARCIS (Netherlands)

Kuiken, H.K.; Bakkers, E.P.A.M.; Ligthart, H.; Kellyb, J.J.

2000-01-01

A model is presented for the rotating ring-ring electrode. Although the electrode is defined by four characteristic lengths, it is shown that the collection efficiency depends on only two dimensionless parameters. A simple relationship between these and the corresponding parameters for the rotating

A note on zero-divisor graph of amalgamated duplication of a ring along an ideal

Directory of Open Access Journals (Sweden)

A. Mallika

2017-04-01

Full Text Available Let R be a commutative ring and I be a non-zero ideal of R. Let R⋈I be the subring of R×R consisting of the elements (r,r+i for r∈R and i∈I. In this paper we characterize all isomorphism classes of finite commutative rings R with identity and ideal I such that Γ(R⋈I is planar. We determine the number of vertices of Γ(R⋈I, a necessary and sufficient condition for the graph Γ(R⋈I to be outerplanar and the domination number of Γ(R⋈I.

Loop calculations for the non-commutative U*(1) gauge field model with oscillator term

International Nuclear Information System (INIS)

Blaschke, Daniel N.; Grosse, Harald; Kronberger, Erwin; Schweda, Manfred; Wohlgenannt, Michael

2010-01-01

Motivated by the success of the non-commutative scalar Grosse-Wulkenhaar model, a non-commutative U * (1) gauge field theory including an oscillator-like term in the action has been put forward in (Blaschke et al. in Europhys. Lett. 79:61002, 2007). The aim of the current work is to analyze whether that action can lead to a fully renormalizable gauge model on non-commutative Euclidean space. In a first step, explicit one-loop graph computations are hence presented, and their results as well as necessary modifications of the action are successively discussed. (orig.)

Commuting, Life-Satisfaction and Internet Addiction

Science.gov (United States)

Lachmann, Bernd; Sariyska, Rayna; Kannen, Christopher; Stavrou, Maria

2017-01-01

The focus of the present work was on the association between commuting (business and private), life satisfaction, stress, and (over-) use of the Internet. Considering that digital devices are omnipresent in buses and trains, no study has yet investigated if commuting contributes to the development of Internet addiction. Overall, N = 5039 participants (N = 3477 females, age M = 26.79, SD = 10.68) took part in an online survey providing information regarding their commuting behavior, Internet addiction, personality, life satisfaction, and stress perception. Our findings are as follows: Personality seems to be less suitable to differentiate between commuter and non-commuter groups, which is possibly due to commuters often not having a choice but simply must accept offered job opportunities at distant locations. Second, the highest levels of satisfaction were found with income and lodging in the group commuting for business purposes. This might be related to the fact that commuting results in higher salaries (hence also better and more expensive housing style) due to having a job in another city which might exceed job opportunities at one’s own living location. Third, within the business-commuters as well as in the private-commuter groups, females had significantly higher levels of stress than males. This association was not present in the non-commuter group. For females, commuting seems to be a higher burden and more stressful than for males, regardless of whether they commute for business or private reasons. Finally, we observed an association between higher stress perception (more negative attitude towards commuting) and Internet addiction. This finding suggests that some commuters try to compensate their perceived stress with increased Internet use. PMID:28981452

Commuting, Life-Satisfaction and Internet Addiction

Directory of Open Access Journals (Sweden)

Bernd Lachmann

2017-10-01

Full Text Available The focus of the present work was on the association between commuting (business and private, life satisfaction, stress, and (over- use of the Internet. Considering that digital devices are omnipresent in buses and trains, no study has yet investigated if commuting contributes to the development of Internet addiction. Overall, N = 5039 participants (N = 3477 females, age M = 26.79, SD = 10.68 took part in an online survey providing information regarding their commuting behavior, Internet addiction, personality, life satisfaction, and stress perception. Our findings are as follows: Personality seems to be less suitable to differentiate between commuter and non-commuter groups, which is possibly due to commuters often not having a choice but simply must accept offered job opportunities at distant locations. Second, the highest levels of satisfaction were found with income and lodging in the group commuting for business purposes. This might be related to the fact that commuting results in higher salaries (hence also better and more expensive housing style due to having a job in another city which might exceed job opportunities at one’s own living location. Third, within the business-commuters as well as in the private-commuter groups, females had significantly higher levels of stress than males. This association was not present in the non-commuter group. For females, commuting seems to be a higher burden and more stressful than for males, regardless of whether they commute for business or private reasons. Finally, we observed an association between higher stress perception (more negative attitude towards commuting and Internet addiction. This finding suggests that some commuters try to compensate their perceived stress with increased Internet use.

Commuting, Life-Satisfaction and Internet Addiction.

Science.gov (United States)

Lachmann, Bernd; Sariyska, Rayna; Kannen, Christopher; Stavrou, Maria; Montag, Christian

2017-10-05

The focus of the present work was on the association between commuting (business and private), life satisfaction, stress, and (over-) use of the Internet. Considering that digital devices are omnipresent in buses and trains, no study has yet investigated if commuting contributes to the development of Internet addiction. Overall, N = 5039 participants (N = 3477 females, age M = 26.79, SD = 10.68) took part in an online survey providing information regarding their commuting behavior, Internet addiction, personality, life satisfaction, and stress perception. Our findings are as follows: Personality seems to be less suitable to differentiate between commuter and non-commuter groups, which is possibly due to commuters often not having a choice but simply must accept offered job opportunities at distant locations. Second, the highest levels of satisfaction were found with income and lodging in the group commuting for business purposes. This might be related to the fact that commuting results in higher salaries (hence also better and more expensive housing style) due to having a job in another city which might exceed job opportunities at one's own living location. Third, within the business-commuters as well as in the private-commuter groups, females had significantly higher levels of stress than males. This association was not present in the non-commuter group. For females, commuting seems to be a higher burden and more stressful than for males, regardless of whether they commute for business or private reasons. Finally, we observed an association between higher stress perception (more negative attitude towards commuting) and Internet addiction. This finding suggests that some commuters try to compensate their perceived stress with increased Internet use.

Non-commutativity in polar coordinates

Energy Technology Data Exchange (ETDEWEB)

Edwards, James P. [Universidad Michoacana de San Nicolas de Hidalgo, Ciudad Universitaria, Instituto de Fisica y Matematicas, Morelia, Michoacan (Mexico)

2017-05-15

We reconsider the fundamental commutation relations for non-commutative R{sup 2} described in polar coordinates with non-commutativity parameter θ. Previous analysis found that the natural transition from Cartesian coordinates to the traditional polar system led to a representation of [r, φ] as an everywhere diverging series. In this article we compute the Borel resummation of this series, showing that it can subsequently be extended throughout parameter space and hence provide an interpretation of this commutator. Our analysis provides a complete solution for arbitrary r and θ that reproduces the earlier calculations at lowest order and benefits from being generally applicable to problems in a two-dimensional non-commutative space. We compare our results to previous literature in the (pseudo-)commuting limit, finding a surprising spatial dependence for the coordinate commutator when θ >> r{sup 2}. Finally, we raise some questions for future study in light of this progress. (orig.)

Contemporary developments in algebraic K-theory

International Nuclear Information System (INIS)

Karoubi, M.; Kuku, A.O.; Pedrini, C.

2003-01-01

The School and Conference on Algebraic K-theory which took place at ICTP July 8-26, 2002 was a follow-up to the earlier one in 1997, and like its predecessor, the 2002 meeting endeavoured to emphasise the multidisciplinary aspects of the subject. However, one special feature of the 2002 School and Conference is that the whole activity was dedicated to H. Bass, one of the founders of Algebraic K-theory, on the occasion of his seventieth birthday. The School during the first two weeks, July 8 to 19 was devoted to expository lectures meant to explore and highlight connections between K-theory and several other areas of mathematics - Algebraic Topology, Number theory, Algebraic Geometry, Representation theory, and Non-commutative Geometry. This volume, constituting the Proceedings of the School, is dedicated to H. Bass. The Proceedings of the Conference during the last week July 22 - 26, which will appear in Special issues of K-theory, is also dedicated to H. Bass. The opening contribution by M. Karoubi to this volume consists of a comprehensive survey of developments in K-theory in the last forty-five years, and covers a very broad spectrum of the subject, including Topological K-theory, Atiyah-Singer index theorem, K-theory of Banach algebras, Higher Algebraic K-theory, Cyclic Homology etc. J. Berrick's contribution on 'Algebraic K-theory and Algebraic Topology' treats the various topological constructions of Algebraic K-theory together with the underlying homotopy theory. Topics covered include the plus construction together with its various ramifications and applications, Topological Hochschild and Cyclic Homology as well as K-theory of the ring of integers. The contributions by M. Kolster titled 'K-theory and Arithmetics' includes such topics as values of zeta functions and relations to K-theory, K-theory of integers in number fields and associated conjectures, Etale cohomology, Iwasawa theory etc. A.O. Kuku's contributions on 'K-theory and Representation theory

Contemporary developments in algebraic K-theory

Energy Technology Data Exchange (ETDEWEB)

Karoubi, M [Univ. Paris (France); Kuku, A O [Abdus Salam International Centre for Theoretical Physics, Trieste (Italy); Pedrini, C [Univ. Genova (Italy)

2003-09-15

The School and Conference on Algebraic K-theory which took place at ICTP July 8-26, 2002 was a follow-up to the earlier one in 1997, and like its predecessor, the 2002 meeting endeavoured to emphasise the multidisciplinary aspects of the subject. However, one special feature of the 2002 School and Conference is that the whole activity was dedicated to H. Bass, one of the founders of Algebraic K-theory, on the occasion of his seventieth birthday. The School during the first two weeks, July 8 to 19 was devoted to expository lectures meant to explore and highlight connections between K-theory and several other areas of mathematics - Algebraic Topology, Number theory, Algebraic Geometry, Representation theory, and Non-commutative Geometry. This volume, constituting the Proceedings of the School, is dedicated to H. Bass. The Proceedings of the Conference during the last week July 22 - 26, which will appear in Special issues of K-theory, is also dedicated to H. Bass. The opening contribution by M. Karoubi to this volume consists of a comprehensive survey of developments in K-theory in the last forty-five years, and covers a very broad spectrum of the subject, including Topological K-theory, Atiyah-Singer index theorem, K-theory of Banach algebras, Higher Algebraic K-theory, Cyclic Homology etc. J. Berrick's contribution on 'Algebraic K-theory and Algebraic Topology' treats the various topological constructions of Algebraic K-theory together with the underlying homotopy theory. Topics covered include the plus construction together with its various ramifications and applications, Topological Hochschild and Cyclic Homology as well as K-theory of the ring of integers. The contributions by M. Kolster titled 'K-theory and Arithmetics' includes such topics as values of zeta functions and relations to K-theory, K-theory of integers in number fields and associated conjectures, Etale cohomology, Iwasawa theory etc. A.O. Kuku's contributions on 'K-theory and Representation theory

Non-commutative multiple-valued logic algebras

CERN Document Server

Ciungu, Lavinia Corina

2014-01-01

This monograph provides a self-contained and easy-to-read introduction to non-commutative multiple-valued logic algebras; a subject which has attracted much interest in the past few years because of its impact on information science, artificial intelligence and other subjects.   A study of the newest results in the field, the monograph includes treatment of pseudo-BCK algebras, pseudo-hoops, residuated lattices, bounded divisible residuated lattices, pseudo-MTL algebras, pseudo-BL algebras and pseudo-MV algebras. It provides a fresh perspective on new trends in logic and algebras in that algebraic structures can be developed into fuzzy logics which connect quantum mechanics, mathematical logic, probability theory, algebra and soft computing.   Written in a clear, concise and direct manner, Non-Commutative Multiple-Valued Logic Algebras will be of interest to masters and PhD students, as well as researchers in mathematical logic and theoretical computer science.

Regular Routes: Deep Mapping a Performative Counterpractice for the Daily Commute 1

Directory of Open Access Journals (Sweden)

Laura Bissell

2015-09-01

Full Text Available This article offers a textual “deep map” of a series of experimental commutes undertaken in the west of Scotland in 2014. Recent developments in the field of transport studies have reconceived travel time as a far richer cultural experience than in previously utilitarian and economic approaches to the “problem” of commuting. Understanding their own commutes in these terms—as spaces of creativity, productivity and transformation—the authors trace the development of a performative “counterpractice” for their daily journeys between home and work. Deep mapping—as a form of “theory-informed story-telling”—is employed as a productive strategy to document this reimagination of ostensibly quotidian and functional travel. Importantly, this particular stage of the project is not presented as an end-point. Striving to develop an ongoing creative engagement with landscape, the authors continue this exploratory mobile research by connecting to other commuters’ journeys, and proposing a series of “strategies” for reimagining the daily commute; a list of prompts for future action within the routines and spaces of commuting. A range of alternative approaches to commuting are offered here to anyone who regularly travels to and from work to employ or develop as they wish, extending the mapping process to other routes and contexts.

Commutative and Non-commutative Parallelogram Geometry: an Experimental Approach

OpenAIRE

Bertram, Wolfgang

2013-01-01

By "parallelogram geometry" we mean the elementary, "commutative", geometry corresponding to vector addition, and by "trapezoid geometry" a certain "non-commutative deformation" of the former. This text presents an elementary approach via exercises using dynamical software (such as geogebra), hopefully accessible to a wide mathematical audience, from undergraduate students and high school teachers to researchers, proceeding in three steps: (1) experimental geometry, (2) algebra (linear algebr...

Projectivity and flatness over the endomorphism ring of a finitely generated comodule

International Nuclear Information System (INIS)

Guedenon, T.

2006-04-01

Let k be a commutative ring, A a k-algebra, C an A- coring that is projective as a left A-module, *C the dual ring of C and Λ a right C-comodule that is finitely generated as a left *C-module. We give necessary and sufficient conditions for projectivity and flatness of a module over the endomorphism ring End C (Λ). If C contains a grouplike element, we can replace Λ with A. (author)

On prime and semiprime rings with generalized derivations and non ...

Indian Academy of Sciences (India)

that any continuous derivation on a commutative Banach algebra has the range in the .... isomorphic to a dense ring of linear transformations of some vector space r over P and .... This section deals with application of our main results. Here A ...

Analysis of a dc commutator machine for exchange of energy with a superconducting coil

International Nuclear Information System (INIS)

Vogel, H.F.

1978-08-01

A 500-kW dc commutator machine, C, is analyzed for use in an LC circuit with a ringing period of approximately 4 s with a superconducting coil, L. Electrical measurements and the important design equations and characteristics are listed. Attention is paid to the calculation of the commutating voltage, which is an important design feature because it sets a limit to the current allowable in the LC circuit, amounting to 6 times rated machine current. The equations for the energy loss components of the generator are given and fitted to experimental coast-down data. With a fitting accuracy of 1.2%, the loss coefficients for the bearing loss, brush loss, windage loss, and tooth eddy current loss in the remanent stator field are thus determined

Commuter Shopping : A study in understanding commuting in the context of shopping

OpenAIRE

Andersson, Åsa; Skoog, Sara; Svensson, Johanna

2014-01-01

Background For ages people have commuted to work, or to other activities, located outside their home municipality. Statements found indicate that the basic decision for commuting are based on utility maximisation and no matter what the character of the benefit is; it should be higher than what can be found closer to the home location. This thesis aims to investigate if people are also commuting with the purpose of obtaining benefits from shopping. The shopping location will in this thesis be ...

Almost-commutative geometries beyond the standard model

International Nuclear Information System (INIS)

Stephan, Christoph A

2006-01-01

In Iochum et al (2004 J. Math. Phys. 45 5003), Jureit and Stephan (2005 J. Math. Phys. 46 043512), Schuecker T (2005 Preprint hep-th/0501181) and Jureit et al (2005 J. Math. Phys. 46 072303), a conjecture is presented that almost-commutative geometries, with respect to sensible physical constraints, allow only the standard model of particle physics and electro-strong models as Yang-Mills-Higgs theories. In this paper, a counter-example will be given. The corresponding almost-commutative geometry leads to a Yang-Mills-Higgs model which consists of the standard model of particle physics and two new fermions of opposite electro-magnetic charge. This is the second Yang-Mills-Higgs model within noncommutative geometry, after the standard model, which could be compatible with experiments. Combined to a hydrogen-like composite particle, these new particles provide a novel dark matter candidate

Classical mechanics in non-commutative phase space

International Nuclear Information System (INIS)

Wei Gaofeng; Long Chaoyun; Long Zhengwen; Qin Shuijie

2008-01-01

In this paper the laws of motion of classical particles have been investigated in a non-commutative phase space. The corresponding non-commutative relations contain not only spatial non-commutativity but also momentum non-commutativity. First, new Poisson brackets have been defined in non-commutative phase space. They contain corrections due to the non-commutativity of coordinates and momenta. On the basis of this new Poisson brackets, a new modified second law of Newton has been obtained. For two cases, the free particle and the harmonic oscillator, the equations of motion are derived on basis of the modified second law of Newton and the linear transformation (Phys. Rev. D, 2005, 72: 025010). The consistency between both methods is demonstrated. It is shown that a free particle in commutative space is not a free particle with zero-acceleration in the non-commutative phase space, but it remains a free particle with zero-acceleration in non-commutative space if only the coordinates are non-commutative. (authors)

Commuting in the settlement system of Serbia

Directory of Open Access Journals (Sweden)

Lukić Vesna

2011-01-01

Full Text Available Territorial organization of settlement system is the framework for internal migration flows. The purpose of this paper is to consider the relation between commuting and the settlement structure. Commuting patterns and characteristics of commuters in Serbia are relatively unknown and insufficiently researched, and as such, can not be adequately used in creation of development strategies and public policies which would include commuters' issues. It has been emphasized the importance of research of commuting ties between different settlements and also pointed out in which way commuting flows could be researched and analyzed by using existing sources, due to better understanding of connections between migrations and settlements. Commuting patterns of workers in Serbia and interrelations between the scope and the structure of commuting flows, as well as the type and population size of settlements in Serbia have been examined. Apart from territorial dimension of commuting phenomenon, socio-economic component of commuting population has also been considered. The use of costumised tabulations from 2002 Census have enabled us to examine all types of commuting and emphasise dominant directions of commuting flows of economically active population according to gender, level of education and sector of economic activity, within the settlement hierarchy. Workers have been classified into seven groups according to place of residence and place of work. The findings reveal there is a clear connection between the hierarchy structure and commuting patterns in Serbia. Further, we find some evidence that only 9,5% of workers - commuters have been working in the settlement of the same population size and type such as their residing settlement. Commuting flows within Serbia’s settlement system point out to certain variations when looking at individual categories of population, but it can be concluded that there is general trend of commuting "upwards" within the

The Rotating Ring-Ring Electrode. Theory and Experiment

NARCIS (Netherlands)

Kuiken, H.K.; Bakkers, E.P.A.M.; Ligthart, H.; Kelly, J.J.

2000-01-01

A model is presented for the rotating ring-ring electrode. Although the electrode is defined by four characteristic lengths, it is shown that the collection efficiency depends on only two dimensionless parameters. A simple relationship between these and the corresponding parameters for the rotating

Algebraic theory of locally nilpotent derivations

CERN Document Server

Freudenburg, Gene

2017-01-01

This book explores the theory and application of locally nilpotent derivations, a subject motivated by questions in affine algebraic geometry and having fundamental connections to areas such as commutative algebra, representation theory, Lie algebras and differential equations. The author provides a unified treatment of the subject, beginning with 16 First Principles on which the theory is based. These are used to establish classical results, such as Rentschler's Theorem for the plane and the Cancellation Theorem for Curves. More recent results, such as Makar-Limanov's theorem for locally nilpotent derivations of polynomial rings, are also discussed. Topics of special interest include progress in classifying additive actions on three-dimensional affine space, finiteness questions (Hilbert's 14th Problem), algorithms, the Makar-Limanov invariant, and connections to the Cancellation Problem and the Embedding Problem. A lot of new material is included in this expanded second edition, such as canonical factoriza...

Perturbing the ground ring of 2D string theory

International Nuclear Information System (INIS)

Barbon, J.L.F.

1992-01-01

In this paper, the authors use free field techniques in D = 2 string theory t calculate the perturbation of the special state algebras when the cosmological constant is turned on. In particular, the authors find that the 'ground cone' preserved by the ring structure is promoted to a three-dimensional hyperboloid as conjectured by Witten. On the other hand, the perturbed (1,1) current algebra of moduli deformations is computed completely, and no simple geometrical interpretation is found. The authors also quote some facts concerning the Liouville matrix a model dictionary in this class of theories

Higher-order paraxial theory of the propagation of ring rippled laser beam in plasma: Relativistic ponderomotive regime

International Nuclear Information System (INIS)

Purohit, Gunjan; Rawat, Priyanka; Chauhan, Prashant; Mahmoud, Saleh T.

2015-01-01

This article presents higher-order paraxial theory (non-paraxial theory) for the ring ripple formation on an intense Gaussian laser beam and its propagation in plasma, taking into account the relativistic-ponderomotive nonlinearity. The intensity dependent dielectric constant of the plasma has been determined for the main laser beam and ring ripple superimposed on the main laser beam. The dielectric constant of the plasma is modified due to the contribution of the electric field vector of ring ripple. Nonlinear differential equations have been formulated to examine the growth of ring ripple in plasma, self focusing of main laser beam, and ring rippled laser beam in plasma using higher-order paraxial theory. These equations have been solved numerically for different laser intensities and plasma frequencies. The well established experimental laser and plasma parameters are used in numerical calculation. It is observed that the focusing of the laser beams (main and ring rippled) becomes fast in the nonparaxial region by expanding the eikonal and other relevant quantities up to the fourth power of r. The splitted profile of laser beam in the plasma is observed due to uneven focusing/defocusing of the axial and off-axial rays. The growths of ring ripple increase when the laser beam intensity increases. Furthermore, the intensity profile of ring rippled laser beam gets modified due to the contribution of growth rate

Reconstruction of the spontaneously broken gauge theory in non-commutative geometry

International Nuclear Information System (INIS)

Okumura, Y.; Morita, K.

1996-01-01

The scheme previously proposed by the present authors is modified to incorporate the strong interaction by affording the direct product internal symmetry. The authors do not need to prepare the extra discrete space for the colour gauge group responsible for the strong interaction to reconstruct the standard model and the left-right symmetric gauge model (LRSM). The approach based on non-commutative geometry leads us to present many attractive points such as the unified picture of the gauge and Higgs field as the generalized connection on the discrete space M 4 x Z N . This approach leads to unified picture of gauge and Higgs fields as the generalized connection. The standard model needs N=2 discrete space for reconstruction in this formalism. LRSM is still alive as a model with the intermediate symmetry of the spontaneously broken SO(10) grand unified theory (GUT). N=3 discrete space is needed for the reconstruction of LRSM to include two Higgs φ and ξ bosons usual transformed as (2, 2 * , 0) and (1, 3, -2) under SU(2) L x SU(2) R x U(1) Y , respectively. ξ is responsible to make v R Majorana fermion and so well explains the seesaw mechanism. Up and down quarks have different masses through the vacuum expectation value of φ

Asymmetric transmission in planar chiral split-ring metamaterials: Microscopic Lorentz-theory approach

DEFF Research Database (Denmark)

Novitsky, Andrey; Galynsky, Vladimir M.; Zhukovsky, Sergei

2012-01-01

The electronic Lorentz theory is employed to explain the optical properties of planar split-ring metamaterials. Starting from the dynamics of individual free carriers, the electromagnetic response of an individual split-ring meta-atom is determined, and the effective permittivity tensor...... of the metamaterial is calculated for normal incidence of light. Whenever the split ring lacks in-plane mirror symmetry, the corresponding permittivity tensor has a crystallographic structure of an elliptically dichroic medium, and the metamaterial exhibits optical properties of planar chiral structures. Its...... transmission spectra are different for right-handed versus left-handed circular polarization of the incident wave, so the structure changes its transmittance when the direction of incidence is reversed. The magnitude of this change is shown to be related to the geometric parameters of the split ring...

A Note on UV/IR Mixing and Non-Commutative Instanton Calculus

CERN Document Server

Bichl, A A

2003-01-01

We estimate the instanton-induced vacuum energy in non-commutative U(1) Yang-Mills theory in four dimensions. In the dilute gas approximation, it is found to be plagued by infrared divergences, as a result of UV/IR mixing.

Bond-equilibrium theory of liquid Se-Te alloys. II. Effect of singly attached ring molecules

Science.gov (United States)

Cutler, Melvin; Bez, Wolfgang G.

1981-06-01

A statistical-mechanical theory for bond equilibrium of chain polymers containing threefold (3F) and onefold (1F) bond defects is extended to include the effects of free ring molecules and ring molecules attached to chains by a single 3F atom. Positively charged singly attached rings are shown to play a key role in bond equilibrium in liquid Sex Te1-x by permitting the formation of ion pairs in which both constituents are effectively chain terminators, thus decreasing the average polymer size. The theory is applied to explain the behavior of the paramagnetic susceptibility, χp, and electronic transport as affected by the Fermi energy EF. It is found that the increase in χp with the concentration of Te is primarily the result of the smaller energy for breaking Te bonds. In addition, attached rings play an important role in determining the effect of temperature on χp. At x<~0.5, the concentrations of both free and attached rings becomes small at high T because of the high concentration of bond defects.

Perturbing the ground ring of 2D string theory

CERN Document Server

Barbón, José L F

1992-01-01

We use free field techniques in D=2 string theory to calculate the perturbation of the special state algebras when the cosmologi- cal constant is turned on. In particular, we find that the "ground cone" preserved by the ring structure is promoted to a three dimen- sional hyperboloid as conjectured by Witten. On the other hand, the perturbed (1,1) a three dimensional hyperboloid as conjectured by Witten. On the other hand, the perturbed (1,1) current algebra of moduli deformations is computed completely, and no simple geometrical inter- pretation is found. We also quote some facts concerning the Liouville/matrix model dictio- nary in this class of theories.

Radar channel balancing with commutation

Energy Technology Data Exchange (ETDEWEB)

Doerry, Armin Walter

2014-02-01

When multiple channels are employed in a pulse-Doppler radar, achieving and maintaining balance between the channels is problematic. In some circumstances the channels may be commutated to achieve adequate balance. Commutation is the switching, trading, toggling, or multiplexing of the channels between signal paths. Commutation allows modulating the imbalance energy away from the balanced energy in Doppler, where it can be mitigated with filtering.

Commuting Pattern with Park-and-Ride Option for Heterogeneous Commuters

Directory of Open Access Journals (Sweden)

Chengjuan Zhu

2013-01-01

Full Text Available We study the effect of the parking on heterogeneous commuters' travel choice in a competitive transportation system which consists of a subway and a parallel road with a bottleneck of limited service capacity. Every morning, commuters either use their private cars only or drive their cars to the bottleneck, park there, and then take the subway to the destination. Considering the effects caused by body congestion in carriage and the parking fees, we developed a bottleneck model to describe the commuters' travel choice. There exist several types of equilibrium that corresponds to user equilibrium. We investigated the influence of the capacity of the bottleneck and the total travel demand on the travel behaviors and on the total social cost. It is shown that there exists a scheme with suitable subway fare and parking fees to implement the minimum total social cost.

Planetary Rings: a Brief History of Observation and Theory

Science.gov (United States)

Nicholson, P. D.

2000-05-01

Over several centuries, and extending down to today, the ring systems encircling Saturn and the other jovian planets have provided an endless source of speculation and theorizing for astronomers, theologians, and physicists. In the past two decades they have also become a testing ground for dynamical models of more distant astrophysical disks, such as those which surround protostars and even the stellar disks of spiral galaxies. I will review some of the early theories, and their sometimes rude confrontation with observational data, starting with Christiaan Huygens and touching on seminal contributions by Laplace, Bessel, Maxwell, Barnard, Russell (of H-R diagram fame) and Jeffreys. In the modern era, observations at infrared and radio wavelengths have revealed Saturn's rings to be composed of large chunks of almost pure water ice, and to have a vertical thickness measured in tens of meters. A renaissance in planetary rings studies occurred in the period 1977--1981, first with the discoveries of the narrow, dark and non-circular rings of Uranus and the tenuous jovian ring system, and capped off by the spectacular images returned during the twin Voyager flybys of Saturn. Along with the completely unsuspected wealth of detail these observations revealed came an unwelcome problem: are the rings ancient or are we privileged to live at a special time in history? The answer to this still-vexing question may lie in the complex gravitational interactions recent studies have revealed between the rings themselves and their retinues of attendant satellites. Between the four known ring systems, we see elegant examples of Lindblad and corotation resonances (first invoked in the galactic context), electromagnetic resonances, many-armed spiral density waves and bending waves, narrow ringlets which exhibit internal modes due to a collective instability, sharp-edged gaps maintained via tidal torques from embedded moonlets, and tenuous dust belts created by meteoroid impact onto

Statistical Ring Catenation under Thermodynamic Control: Should the Jacobson-Stockmayer Cyclization Theory Take into Account Catenane Formation?

Science.gov (United States)

Di Stefano, Stefano; Ercolani, Gianfranco

2017-01-26

An extension of the Jacobson-Stockmayer theory is presented to include the reversible formation of [2]catenanes in a ring-chain system under thermodynamic control. The extended theory is based on the molar catenation constant, measuring the ease of catenation of two ring oligomers, whose expression was obtained in a previous work. Two scenarios have been considered: that of "thick" (hydrocarbon-like) chains and that of "thin" (DNA-like) chains. In the case of "thick" chains, the formation of catenanes can be neglected, unless in the unlikely case of a very large value of the equilibrium constant for linear propagation (K ≈ 10 8 mol -1 L, or larger). For K tending to infinity, the system becomes a chain-free system where only ring-catenane equilibria occur. Under this condition, there is a critical concentration below which only rings are present at equilibrium and above which the ring fraction remains constant, and the excess monomer is converted only into catenanes. In the case of "thin" chains, the formation of catenanes cannot be neglected even for values of K as low as 10 2 mol -1 L, thus justifying the use of the extended theory.

Rings with involution whose symmetric elements are central

Directory of Open Access Journals (Sweden)

Taw Pin Lim

1980-01-01

Full Text Available In a ring R with involution whose symmetric elements S are central, the skew-symmetric elements K form a Lie algebra over the commutative ring S. The classification of such rings which are 2-torsion free is equivalent to the classification of Lie algebras K over S equipped with a bilinear form f that is symmetric, invariant and satisfies [[x,y],z]=f(y,zx−f(z,xy. If S is a field of char ≠2, f≠0 and dimK>1 then K is a semisimple Lie algebra if and only if f is nondegenerate. Moreover, the derived algebra K′ is either the pure quaternions over S or a direct sum of mutually orthogonal abelian Lie ideals of dim≤2.

Augmentation Quotients for Real Representation Rings of Cyclic ...

Indian Academy of Sciences (India)

29

By [1], R(G) is a commutative ring with an identity element. Its underlying group is a ... first author and Guoping Tang solved it in [5] an thereby solved the problem ... groups. Lemma 2.4 Let H be a finite generated free abelian group of rank N. If the ..... We study this case using the same method as in the above subsection.

On the interrelations between migration and commuting

Directory of Open Access Journals (Sweden)

Lukić Vesna

2013-01-01

Full Text Available In this paper, we emphasise the significance of studying the interrelations between commuting and migration. The aim of the paper is to point out the factors which affect these interrelations (demographic and socio-economic characteristics of migrants and commuters, labour market, real estate market, information, life style, etc., with the special emphasis on the role of commuting distance onto the chosen mobility type. Besides theorethical frameworks and results of the selected foreign researches up to date, the overview of research of interrelations between migration and commuting in Serbia has also been presented. While earlier studies conducted by Gawryszenski (1978, Termote (1980 and Reitsma&Vergoossen (1987 pointed to the replacement of migration types between each other within country, in recent literature the interaction between migration and commuting has been studied in a trans-boundary context of the contemporary EU. Modern trend of long distance commuting instead of migration and the concept of substitution/replacement regarding migration and commuting have also been discussed. In Serbia, there is a positive correlation between commuting outflows and immigration in rural settlements of Vojvodina province. Namely, commuting and migration are complement, which is the characteristic of both processes sub-urbanisation and ex-urbanisation (Lukić, 2012. In addition to ownership of real estate and previous migration experience, marital status influenced the chosen mobility type in Serbia as well. Adjustment to changes of Serbian labour market is mostly conducted via migration (Miletić, Lukić, Miljanović, 2011. Interrelations between migration and commuting are very significant due to the tendency of transformation of some commuters into migrants. This process has its consequences, both on demographic as well as the overall socio-economic development of the area of commuters’ origin and destination. However, even though the surveys

The use of ultraproducts in commutative algebra

CERN Document Server

Schoutens, Hans

2010-01-01

In spite of some recent applications of ultraproducts in algebra, they remain largely unknown to commutative algebraists, in part because they do not preserve basic properties such as Noetherianity. This work wants to make a strong case against these prejudices. More precisely, it studies ultraproducts of Noetherian local rings from a purely algebraic perspective, as well as how they can be used to transfer results between the positive and zero characteristics, to derive uniform bounds, to define tight closure in characteristic zero, and to prove asymptotic versions of homological conjectures in mixed characteristic. Some of these results are obtained using variants called chromatic products, which are often even Noetherian. This book, neither assuming nor using any logical formalism, is intended for algebraists and geometers, in the hope of popularizing ultraproducts and their applications in algebra.

Stereochemical Basis for a Unified Structure Activity Theory of Aromatic and Heterocyclic Rings in Selected Opioids and Opioid Peptides

Directory of Open Access Journals (Sweden)

Joel S. Goldberg

2010-02-01

Full Text Available This paper presents a novel unified theory of the structure activity relationship of opioids and opioid peptides. It is hypothesized that a virtual or known heterocyclic ring exists in all opioids which have activity in humans, and this ring occupies relative to the aromatic ring of the drug, approximately the same plane in space as the piperidine ring of morphine. Since the rings of morphine are rigid, and the aromatic and piperidine rings are critical structural components for morphine’s analgesic properties, the rigid morphine molecule allows for approximations of the aromatic and heterocyclic relationships in subsequent drug models where bond rotations are common. This hypothesis and five propositions are supported by stereochemistry and experimental observations. Proposition #1 The structure of morphine provides a template. Proposition #2 Steric hindrance of some centric portion of the piperidine ring explains antagonist properties of naloxone, naltrexone and alvimopam. Proposition #3 Methadone has an active conformation which contains a virtual heterocyclic ring which explains its analgesic activity and racemic properties. Proposition #4 The piperidine ring of fentanyl can assume the morphine position under conditions of nitrogen inversion. Proposition #5 The first 3 amino acid sequences of beta endorphin (l-try-gly-gly and the active opioid dipeptide, l-tyr-pro, (as a result of a peptide turn and zwitterion bonding form a virtual piperazine-like ring which is similar in size, shape and location to the heterocyclic rings of morphine, meperidine, and methadone. Potential flaws in this theory are discussed. This theory could be important for future analgesic drug design.

Non-commutative cryptography and complexity of group-theoretic problems

CERN Document Server

Myasnikov, Alexei; Ushakov, Alexander

2011-01-01

This book is about relations between three different areas of mathematics and theoretical computer science: combinatorial group theory, cryptography, and complexity theory. It explores how non-commutative (infinite) groups, which are typically studied in combinatorial group theory, can be used in public-key cryptography. It also shows that there is remarkable feedback from cryptography to combinatorial group theory because some of the problems motivated by cryptography appear to be new to group theory, and they open many interesting research avenues within group theory. In particular, a lot of emphasis in the book is put on studying search problems, as compared to decision problems traditionally studied in combinatorial group theory. Then, complexity theory, notably generic-case complexity of algorithms, is employed for cryptanalysis of various cryptographic protocols based on infinite groups, and the ideas and machinery from the theory of generic-case complexity are used to study asymptotically dominant prop...

An anthology of non-local QFT and QFT on non-commutative spacetime

Science.gov (United States)

Schroer, Bert

2005-09-01

Ever since the appearance of renormalization theory, there have been several differently motivated attempts at non-localized (in the sense of not generated by pointlike fields) relativistic particle theories, the most recent one being at QFT on non-commutative Minkowski spacetime. The often conceptually uncritical and historically forgetful contemporary approach to these problems calls for a critical review in the light of previous results on this subject.

An anthology of non-local QFT and QFT on non-commutative spacetime

International Nuclear Information System (INIS)

Schroer, Bert

2005-01-01

Ever since the appearance of renormalization theory, there have been several differently motivated attempts at non-localized (in the sense of not generated by pointlike fields) relativistic particle theories, the most recent one being at QFT on non-commutative Minkowski spacetime. The often conceptually uncritical and historically forgetful contemporary approach to these problems calls for a critical review in the light of previous results on this subject

8 CFR 211.5 - Alien commuters.

Science.gov (United States)

2010-01-01

... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Alien commuters. 211.5 Section 211.5 Aliens...: IMMIGRANTS; WAIVERS § 211.5 Alien commuters. (a) General. An alien lawfully admitted for permanent residence.... An alien commuter engaged in seasonal work will be presumed to have taken up residence in the United...

Commutation relations for functions of operators

International Nuclear Information System (INIS)

Transtrum, Mark K.; Van Huele, Jean-Francois S.

2005-01-01

We derive an expression for the commutator of functions of operators with constant commutations relations in terms of the partial derivatives of these functions. This result extends the well-known commutation relation between one operator and a function of another operator. We discuss the range of applicability of the formula with examples in quantum mechanics

Covariance of time-ordered products implies local commutativity of fields

International Nuclear Information System (INIS)

Greenberg, O.W.

2006-01-01

We formulate Lorentz covariance of a quantum field theory in terms of covariance of time-ordered products (or other Green's functions). This formulation of Lorentz covariance implies spacelike local commutativity or anticommutativity of fields, sometimes called microscopic causality or microcausality. With this formulation microcausality does not have to be taken as a separate assumption

Active commuting: prevalence, barriers, and associated variables.

Science.gov (United States)

Silva, Kelly Samara; Vasques, Daniel Giordani; Martins, Caroline de Oliveira; Williams, Laura Ashley; Lopes, Adair S

2011-08-01

Research has demonstrated that adolescents who actively commute have higher levels of physical activity (PA), which have declined precipitously over the past 30 years. The purpose of this study was to describe the prevalence of active commuting to school; and to identify barriers associated with active commuting. A cross-sectional study was conducted with 1672 students (46.8% boys and 53.2% girls) from 11 to 17 years of age in Caxias do Sul/RS, Brazil. The students were asked to answer questionnaires about active transport, PA, and sedentary behaviors. They also completed a cardiovascular fitness test and body composition measurements. The study used a multivariate Poisson regression analysis. A total of 62.5% of students were observed to actively commute and the prevalence ratio (PR) of not actively commuting was associated with the type of school (Private: 2.41; 1.47, 3.95) and the time spent on commuting (>20 min: 1.93; 1.23, 3.03). The associated barriers to passive commuting were distance (3.02; 1.95, 4.71), crime/danger (2.65; 1.82, 3.85), and traffic (1.75; 1.19, 2.58). This study showed that environmental variables were strongly associated with active commuting. However, no alterations in body composition or other behavioral variables were observed after adjustment.

Causality, spin, and equal-time commutators

International Nuclear Information System (INIS)

Abdel-Rahman, A.M.

1975-01-01

We study the causality constraints on the structure of the Lorentz-antisymmetric component of the commutator of two conserved isovector currents between fermion states of equal momenta. We discuss the sum rules that follow from causality and scaling, using the recently introduced refined infinite-momentum technique. The complete set of sum rules is found to include the spin-dependent fixed-mass sum rules obtained from light-cone commutators. The causality and scaling restrictions on the structure of the electromagnetic equal-time commutators are discussed, and it is found, in particular, that causality requires the spin-dependent part of the matrix element for the time-space electromagnetic equal-time commutator to vanish identically. It is also shown, in comparison with the electromagnetic case, that the corresponding matrix element for the time-space isovector current equal-time commutator is required, by causality, to have isospin-antisymmetric tensor and scalar operator Schwinger terms

Euler Polynomials and Identities for Non-Commutative Operators

OpenAIRE

De Angelis, V.; Vignat, C.

2015-01-01

Three kinds of identities involving non-commutating operators and Euler and Bernoulli polynomials are studied. The first identity, as given by Bender and Bettencourt, expresses the nested commutator of the Hamiltonian and momentum operators as the commutator of the momentum and the shifted Euler polynomial of the Hamiltonian. The second one, due to J.-C. Pain, links the commutators and anti-commutators of the monomials of the position and momentum operators. The third appears in a work by Fig...

Carbon monoxide levels in popular passenger commuting modes traversing major commuting routes in Hong Kong

International Nuclear Information System (INIS)

Chan, L.Y.; Liu, Y.M.

2001-01-01

Vehicle exhaust is a major source of air pollution in metropolitan cities. Commuters are exposed to high traffic-related pollutant concentrations. Public transportation is the most popular commuting mode in Hong Kong and there are about 10.8 million passenger trips every day. Two-thirds of them are road commuters. An extensive survey was conducted to measure carbon monoxide in three popular passenger commuting modes, bus, minibus, and taxi, which served, respectively, 3.91 million, 1.76 million and 1.31 million passenger trips per day in 1998. Three types of commuting microenvironments were selected: urban-urban, urban-suburban and urban-rural. Results indicated that in-vehicle CO level increased in the following order: bus, minibus and taxi. The overall average in-vehicle CO level in air-conditioned bus, minibus and taxi were 1.8, 2.9 and 3.3ppm, respectively. The average concentration level between air-conditioned buses (1.8ppm) and non-air-conditioned buses (1.9ppm) was insignificant. The fluctuation of in-vehicle CO level of non-air-conditioned vehicle followed the variation of out-vehicle CO concentration. Our result also showed that even in air-conditioned vehicles, the in-vehicle CO concentration was affected by the out-vehicle CO concentration although there exists a smoothing out effect. The in-vehicle CO level was the highest in urban-suburban commuting routes and was followed by urban-urban routes. The in-vehicle CO level in urban-rural routes was the lowest. The highest CO level was recorded after the vehicle traversed through tunnel.. The average CO exposure level of public road transportation commuters in Honk Kong was lower than most other cities. Factors governing the CO levels were also discussed. (Author)

Investigation of the annihilation reaction e+ e- → φ in the Orsay Collider Ring

International Nuclear Information System (INIS)

Richard, Francois

1970-01-01

This research thesis mainly reports an experiment which aimed at measuring the disintegration partial width of the φ into e + e - by studying the annihilation reaction (e + e - → φ) in the Orsay Collider Ring (ACO). In a first part, the author presents the theoretical framework which is based on the Lee-Weinberg-Zumino gauge fields: definition of gauge fields, commutation relationship between them, presentation of Weinberg sum rules, interpretation of sum rules in terms of asymptotic symmetry, formulation of vector dominance meson, application of sum rules, Sugawara model. In a second part, the author discusses the conditions of detection of the two φ modes, and the elimination of parasite reactions. Analysis criteria are then determined after a brief description of the experimental installation. The installation efficiency and some various corrections are also discussed. Results are then interpreted by means of a theory-based curved. A general interpretation of Orsay results is proposed on the ρ, ω and φ within the framework of the theory previously presented

Black rings

International Nuclear Information System (INIS)

Emparan, Roberto; Reall, Harvey S

2006-01-01

A black ring is a five-dimensional black hole with an event horizon of topology S 1 x S 2 . We provide an introduction to the description of black rings in general relativity and string theory. Novel aspects of the presentation include a new approach to constructing black ring coordinates and a critical review of black ring microscopics. (topical review)

Commutating Permanent-Magnet Motors At Low Speed

Science.gov (United States)

Dolland, C.

1985-01-01

Circuit provides forced commutation during starting. Forced commutation circuit diverts current from inverter SCR's and turns SCR's off during commutation intervals. Silicon controlled rectifier in circuit unnecessary when switch S10 replaced by high-current, high-voltage transistor. At present, high-current, low-voltage device must suffice.

Reversal thyristor-relay direct current commutator

International Nuclear Information System (INIS)

Ivanenko, A.I.

1982-01-01

A thyristor-relay commutator used for alteration of the leading magnetic field direction in experiments with polarized neutrons is described. The commutator flowsheet is presented. Thyristors, connected so as to allow the relay trigger operation mode, are used as controllable electronic relay. Two connected in series coils with the total inductance of the order of 0.28 H serve as the electronic relay load. The arc-free current commutation is effected at the moment of the minimal current across the load terminals, which allows to easily reverse the current up to 10 A at a volatage, v <= 150 V. The experience gained within a year of operation has shown that the commutator meets the requirements of reliability and tuning

Two-dimensional black holes and non-commutative spaces

International Nuclear Information System (INIS)

Sadeghi, J.

2008-01-01

We study the effects of non-commutative spaces on two-dimensional black hole. The event horizon of two-dimensional black hole is obtained in non-commutative space up to second order of perturbative calculations. A lower limit for the non-commutativity parameter is also obtained. The observer in that limit in contrast to commutative case see two horizon

A reachability test for systems over polynomial rings using Gröbner bases

NARCIS (Netherlands)

Habets, L.C.G.J.M.

1992-01-01

Conditions for the reachability of a system over a polynomial ring are well known in the literature. However, the verification of these conditions remained a difficult problem in general. Application of the Gröbner Basis method from constructive commutative algebra makes it possible to carry out

A first course in noncommutative rings

CERN Document Server

Lam, T Y

2001-01-01

A First Course in Noncommutative Rings, an outgrowth of the author's lectures at the University of California at Berkeley, is intended as a textbook for a one-semester course in basic ring theory. The material covered includes the Wedderburn-Artin theory of semisimple rings, Jacobson's theory of the radical, representation theory of groups and algebras, prime and semiprime rings, local and semilocal rings, perfect and semiperfect rings, etc. By aiming the level of writing at the novice rather than the connoisseur and by stressing th the role of examples and motivation, the author has produced a text that is suitable not only for use in a graduate course, but also for self- study in the subject by interested graduate students. More than 400 exercises testing the understanding of the general theory in the text are included in this new edition.

Piranti Lunak Pengujian Struktur Matematika Grup, Ring, Field Berbasis Osp (Open Source Program

Directory of Open Access Journals (Sweden)

Ngarap Im Manik

2014-06-01

Full Text Available This design of a computer software is a development and continuation of the software made on the previous research (2009/2010. However, this further research developed and expanded the scopes of testing more on the Siclic Group, Isomorphism Group, Semi Group, Sub Group and Abelian Group, Factor Ring, Sub Ring and Polynomial Ring; developed on the OSP (Open Source Program-based. The software was developed using the OSP-based language programming, such Java, so it is open and free to use for its users. This research succeeded to develop an open source software of Java program that can be used for testing specific mathematical Groups, such Ciclic Group, Isomorphism Group, Semi Group, Sub Group and Abelian Group, and Rings, Commutative Ring, Division Ring, Ideal Sub Ring, Ring Homomorphism, Ring Epimorphism and Fields. By the results, the software developed was able to test as same as the results from manual testing.

Marginal and non-commutative deformations via non-abelian T-duality

Energy Technology Data Exchange (ETDEWEB)

Hoare, Ben [Institut für Theoretische Physik, ETH Zürich,Wolfgang-Pauli-Strasse 27, 8093 Zürich (Switzerland); Thompson, Daniel C. [Theoretische Natuurkunde, Vrije Universiteit Brussel & The International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium)

2017-02-10

In this short article we develop recent proposals to relate Yang-Baxter sigma-models and non-abelian T-duality. We demonstrate explicitly that the holographic space-times associated to both (multi-parameter)-β-deformations and non-commutative deformations of N=4 super Yang-Mills gauge theory including the RR fluxes can be obtained via the machinery of non-abelian T-duality in Type II supergravity.

Commutation circuit for an HVDC circuit breaker

Science.gov (United States)

Premerlani, William J.

1981-01-01

A commutation circuit for a high voltage DC circuit breaker incorporates a resistor capacitor combination and a charging circuit connected to the main breaker, such that a commutating capacitor is discharged in opposition to the load current to force the current in an arc after breaker opening to zero to facilitate arc interruption. In a particular embodiment, a normally open commutating circuit is connected across the contacts of a main DC circuit breaker to absorb the inductive system energy trapped by breaker opening and to limit recovery voltages to a level tolerable by the commutating circuit components.

Semiclassical and quantum motions on the non-commutative plane

International Nuclear Information System (INIS)

Baldiotti, M.C.; Gazeau, J.P.; Gitman, D.M.

2009-01-01

We study the canonical and the coherent state quantizations of a particle moving in a magnetic field on the non-commutative plane. Using a θ-modified action, we perform the canonical quantization and analyze the gauge dependence of the theory. We compare coherent states quantizations obtained through Malkin-Man'ko states and circular squeezed states. The relation between these states and the 'classical' trajectories is investigated, and we present numerical explorations of some semiclassical quantities.

Prime alternative algebras that are nearly commutative

International Nuclear Information System (INIS)

Pchelintsev, S V

2004-01-01

We prove that by deforming the multiplication in a prime commutative alternative algebra using a C-operation we obtain a prime non-commutative alternative algebra. Under certain restrictions on non-commutative algebras this relation between algebras is reversible. Isotopes are special cases of deformations. We introduce and study a linear space generated by the Bruck C-operations. We prove that the Bruck space is generated by operations of rank 1 and 2 and that 'general' Bruck operations of rank 2 are independent in the following sense: a sum of n operations of rank 2 cannot be written as a linear combination of (n-1) operations of rank 2 and an arbitrary operation of rank 1. We describe infinite series of non-isomorphic prime non-commutative algebras of bounded degree that are deformations of a concrete prime commutative algebra

Non-commutative geometry on quantum phase-space

International Nuclear Information System (INIS)

Reuter, M.

1995-06-01

A non-commutative analogue of the classical differential forms is constructed on the phase-space of an arbitrary quantum system. The non-commutative forms are universal and are related to the quantum mechanical dynamics in the same way as the classical forms are related to classical dynamics. They are constructed by applying the Weyl-Wigner symbol map to the differential envelope of the linear operators on the quantum mechanical Hilbert space. This leads to a representation of the non-commutative forms considered by A. Connes in terms of multiscalar functions on the classical phase-space. In an appropriate coincidence limit they define a quantum deformation of the classical tensor fields and both commutative and non-commutative forms can be studied in a unified framework. We interprete the quantum differential forms in physical terms and comment on possible applications. (orig.)

Commuting behavior of western U.S. residents

Energy Technology Data Exchange (ETDEWEB)

Caviglia, J. [Tennessee Univ., Knoxville, TN (United States)]|[Oak Ridge National Lab., TN (United States)

1996-06-01

Estimation and interpretation of commutes to work has been studied extensively with respect to gender, race, and income. While the literature is extensive in these areas, there has been little research on regional differences between US states and territories. Since data which reports the commute to work is in average minutes, the distance traveled is estimated using estimates of the distance between home and work county centroids. The models differ in estimation of in-county commutes. The first assumes that the commute is equal to the radius of the county and the second estimates the commute as a weighted distance based on place location. Two data sets are compared, US National Guard data and US census data. Goal of this paper is to make conclusions about the commuting behavior of western residents through the use of these estimates, and therefore to provide a estimation method for distance commutes which can be used in further research. It is concluded that the radius method of estimation may be an over estimation, in particular in the western states. Since the non-western states are generally more homogeneously populated, this overestimation is not observed. It is recommended that the place location method be used for similar research, in particular studies dealing with western states. Suggestions are made for further research and recommendations are made for the US Army National Guard in regards to recruiting.

Trade-offs between commuting time and health-related activities.

Science.gov (United States)

Christian, Thomas J

2012-10-01

To further understand documented associations between obesity and urban sprawl, this research describes individuals' trade-offs between health-related activities and commuting time. A cross-section of 24,861 working-age individuals employed full-time and residing in urban counties is constructed from the American Time Use Survey (2003-2010). Data are analyzed using seemingly unrelated regressions to quantify health-related activity decreases in response to additional time spent commuting. Outcomes are total daily minutes spent in physical activity at a moderate or greater intensity, preparing food, eating meals with family, and sleeping. Commuting time is measured as all travel time between home and work and vice versa. The mean commuting time is 62 min daily, the median is 55 min, and 10.1% of workers commute 120 min or more. Spending an additional 60 min daily commuting above average is associated with a 6% decrease in aggregate health-related activities and spending an additional 120 min is associated with a 12% decrease. The greatest percentage of commuting time comes from sleeping time reductions (28-35%). Additionally, larger proportions of commuting time are taken from physical activity and food preparation relative to the mean commuting length: of 60 min spent commuting, 16.1% is taken from physical activity and 4.1% is taken from food preparation; of 120 min commuting, 20.3% is taken from physical activity and 5.6% is taken from food preparation. The results indicate that longer commutes are associated with behavioral patterns which over time may contribute to obesity and other poor health outcomes. These findings will assist both urban planners and researchers wishing to understand time constraints' impacts on health.

Active matter beyond mean-field: ring-kinetic theory for self-propelled particles.

Science.gov (United States)

Chou, Yen-Liang; Ihle, Thomas

2015-02-01

Recently, Hanke et al. [Phys. Rev. E 88, 052309 (2013)] showed that mean-field kinetic theory fails to describe collective motion in soft active colloids and that correlations must not be neglected. Correlation effects are also expected to be essential in systems of biofilaments driven by molecular motors and in swarms of midges. To obtain correlations in an active matter system from first principles, we derive a ring-kinetic theory for Vicsek-style models of self-propelled agents from the exact N-particle evolution equation in phase space. The theory goes beyond mean-field and does not rely on Boltzmann's approximation of molecular chaos. It can handle precollisional correlations and cluster formation, which are both important to understand the phase transition to collective motion. We propose a diagrammatic technique to perform a small-density expansion of the collision operator and derive the first two equations of the Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy. An algorithm is presented that numerically solves the evolution equation for the two-particle correlations on a lattice. Agent-based simulations are performed and informative quantities such as orientational and density correlation functions are compared with those obtained by ring-kinetic theory. Excellent quantitative agreement between simulations and theory is found at not-too-small noises and mean free paths. This shows that there are parameter ranges in Vicsek-like models where the correlated closure of the BBGKY hierarchy gives correct and nontrivial results. We calculate the dependence of the orientational correlations on distance in the disordered phase and find that it seems to be consistent with a power law with an exponent around -1.8, followed by an exponential decay. General limitations of the kinetic theory and its numerical solution are discussed.

Commute Scheduling and Congestion in a Monocentric City

DEFF Research Database (Denmark)

Fosgerau, Mogens; Kim, Jinwon; Ranjan, Abhishek

2017-01-01

to the CBD, residents choose their commute departure time jointly with residential location and housing consumption. Commuters arrive at the bottleneck in sequence sorted by residential location, so that more distant residents arrive later. The socially optimal toll makes central residents commute earlier...

Perfect commuting-operator strategies for linear system games

Science.gov (United States)

Cleve, Richard; Liu, Li; Slofstra, William

2017-01-01

Linear system games are a generalization of Mermin's magic square game introduced by Cleve and Mittal. They show that perfect strategies for linear system games in the tensor-product model of entanglement correspond to finite-dimensional operator solutions of a certain set of non-commutative equations. We investigate linear system games in the commuting-operator model of entanglement, where Alice and Bob's measurement operators act on a joint Hilbert space, and Alice's operators must commute with Bob's operators. We show that perfect strategies in this model correspond to possibly infinite-dimensional operator solutions of the non-commutative equations. The proof is based around a finitely presented group associated with the linear system which arises from the non-commutative equations.

Factors affecting commuter rail energy efficiency.

Science.gov (United States)

2016-02-17

The objective of this study is to develop a planninglevel model of commuter rail energy efficiency. The : environmental benefits of commuter rail are often cited as one of the key benefits and motivators for its rapid development as a public trans...

Commuting quantum traces for quadratic algebras

International Nuclear Information System (INIS)

Nagy, Zoltan; Avan, Jean; Doikou, Anastasia; Rollet, Genevieve

2005-01-01

Consistent tensor products on auxiliary spaces, hereafter denoted 'fusion procedures', and commuting transfer matrices are defined for general quadratic algebras, nondynamical and dynamical, inspired by results on reflection algebras. Applications of these procedures then yield integer-indexed families of commuting Hamiltonians

Semiclassical and quantum motions on the non-commutative plane

Energy Technology Data Exchange (ETDEWEB)

Baldiotti, M.C., E-mail: baldiott@fma.if.usp.b [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318-CEP, 05315-970 Sao Paulo, S.P. (Brazil); Gazeau, J.P., E-mail: gazeau@apc.univ-paris7.f [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318-CEP, 05315-970 Sao Paulo, S.P. (Brazil); Gitman, D.M., E-mail: gitman@dfn.if.usp.b [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318-CEP, 05315-970 Sao Paulo, S.P. (Brazil)

2009-10-19

We study the canonical and the coherent state quantizations of a particle moving in a magnetic field on the non-commutative plane. Using a theta-modified action, we perform the canonical quantization and analyze the gauge dependence of the theory. We compare coherent states quantizations obtained through Malkin-Man'ko states and circular squeezed states. The relation between these states and the 'classical' trajectories is investigated, and we present numerical explorations of some semiclassical quantities.

A commutator

Energy Technology Data Exchange (ETDEWEB)

Matsukura, K.

1981-06-18

The synchronous, electric micromotor of a time commutator, by means of a three staged cylindrical gear drive rotates a disk with a semirounded segmented notch, which, in turn, drives a Maltese cross. The gear drum, linked with the Maltese cross rotates a disk with an indicator, equipped with radial, spherical grooves, equidistant from each other. Radially projecting catches, which are used with rotation of the disk to accomplish elastic movement of a vertical shaft under the effect of a three beam, asymmetrical star, are mounted in the disk's grooves by means of spring loaded locking devices, in accordance with the required time technological program. There are driving and locking cams located on the lower end of the shaft. The first is of pear shaped section and provides drive to the microswitch, which commutates the output electrical circuit of the apparatus.

Pion--nucleon sigma-commutator

International Nuclear Information System (INIS)

Banerjee, M.K.; Cammarata, J.B.

1977-07-01

The reasons for the large discrepancies in the magnitude of the πN sigma-commutator, sigma(πN), obtained by several authors are discussed using dynamic theory of the πN scattering amplitude. With sigma(πN) approximately 25 MeV this theory reproduces reasonably well both the experimental S-wave phase shifts at low energies and the amplitudes C approximately/sup(+)/(ν=0,t less than or equal to 0) determined by Langbein. In the method of Cheng and Dashen the value of sigma(πN) is obtained from these amplitudes by extrapolation to t = 2m 2 /sub π/. A study of the experimental D-wave ''scattering lengths'' implies that the coefficient of the term quadratic in t in the Hoehler expansion of C approximately/sup(+)/(0,t) is negative. Adding such a term to the results of the S-wave theory will tend to improve the agreement for C approximately/sup (+)/(0,t less than or equal to 0). These results suggest that the large ''world value'' sigma(πN) = 65 +- 5 MeV obtained using the Cheng-Dashen method is a consequence of errors in the extrapolation of amplitudes to the unphysical point ν = 0, t = 2m 2 /sub π/. Only the smaller value sigma(πN) approximately 25 MeV appears to be consistent with the experimental data and theoretical constraints

Course on algebra

International Nuclear Information System (INIS)

Brundu, M.; Logar, A.

1995-10-01

In the first chapter, the basic properties of groups are briefly discussed, including finite groups and symmetric groups. In the second chapter commutative rings are discussed (ideals, polynomial rings and noetherian rings). The third chapter is about Galois theory (extensions of morphisims, Galois correspondence, and solvability by radicals). 8 refs, 1 tab

Spectrophotometric study of Saturn's main rings by means of Monte Carlo ray-tracing and Hapke's theory

Science.gov (United States)

Ciarniello, Mauro; Filacchione, Gianrico; D'Aversa, Emiliano; Cuzzi, Jeffrey N.; Capaccioni, Fabrizio; Hedman, Matthew M.; Dalle Ore, Cristina M.; Nicholson, Philip D.; Clark, Roger Nelson; Brown, Robert H.; Cerroni, Priscilla; Spilker, Linda

2017-10-01

This work is devoted to the investigation of the spectrophotometric properties of Saturn's rings from Cassini-VIMS (Visible and Infrared Mapping Spectrometer) observations. The dataset used for this analysis is represented by ten radial spectrograms of the rings which have been derived in Filacchione et al. (2014) by radial mosaics produced by VIMS. Spectrograms report the measured radiance factor of the main Saturn's rings as a function of both radial distance (from 73.500 to 141.375 km) and wavelength (0.35-5.1 µm) for different observation geometries (phase angle ranging in the 1.9°-132.2° interval). We take advantage of a Monte Carlo ray-tracing routine to characterize the photometric behavior of the rings at each wavelength and derive the spectral Bond albedo of rings particles. This quantity is used to infer the composition of the regolith covering rings particles by applying Hapke's theory. Four different regions, characterized by different optical depths, and respectively located in the C ring, inner B ring, mid B ring and A ring, have been investigated. Results from spectral modeling indicate that rings spectrum can be described by water ice with minimal inclusion of organic materials (tholin, exogenous material, which is more effective in the less dense regions of the rings because of their lower content of pure water ice.

Geometry, commutation relations and the quantum fictitious force

DEFF Research Database (Denmark)

Botero, J.; Cirone, M.A.; Dahl, Jens Peder

2003-01-01

We express the commutation relation between the operators of the momentum and the radial unit vectors in D dimensions in differential and integral form. We connect this commutator with the quantum fictitious potential emerging in the radial Schrodinger equation of an s-wave.......We express the commutation relation between the operators of the momentum and the radial unit vectors in D dimensions in differential and integral form. We connect this commutator with the quantum fictitious potential emerging in the radial Schrodinger equation of an s-wave....

Commuter partnerships : balancing home, family, and distant work

NARCIS (Netherlands)

van der Klis, M.

2009-01-01

This study is about commuter partnerships. The commuter partnership is a particular non-standard household arrangement in which, for part of the time, one partner lives near his or her work and away from the communal family home, because the commuting distance is too great to travel on a daily

Differential Galois obstructions for non-commutative integrability

Energy Technology Data Exchange (ETDEWEB)

Maciejewski, Andrzej J. [Institute of Astronomy, University of Zielona Gora, Podgorna 50, PL-65-246 Zielona Gora (Poland)], E-mail: maciejka@astro.ia.uz.zgora.pl; Przybylska, Maria [Torun Centre for Astronomy, N. Copernicus University, Gagarina 11, PL-87-100 Torun (Poland)], E-mail: mprzyb@astri.uni.torun.pl

2008-08-11

We show that if a holomorphic Hamiltonian system is holomorphically integrable in the non-commutative sense in a neighbourhood of a non-equilibrium phase curve which is located at a regular level of the first integrals, then the identity component of the differential Galois group of the variational equations along the phase curve is Abelian. Thus necessary conditions for the commutative and non-commutative integrability given by the differential Galois approach are the same.

When is Commuting Desirable to the Individual?

OpenAIRE

Ory, David T.; Mokhtarian, Patricia L.; Redmond, Lothlorien S.; Collantes, Gustavo O.; Choo, Sangho

2004-01-01

Commuting is popularly viewed as a stressful, costly, time-wasting experience from the individual perspective, with the attendant congestion imposing major social costs as well. However, several authors have noted that commuting can also offer benefits to the individual, serving as a valued transition between the home and work realms of personal life. Using survey data collected from about 1,300 commuting workers in three San Francisco Bay Area neighborhoods, empirical models are developed fo...

Canonical commutation relations - historical aspect and new results

International Nuclear Information System (INIS)

Mnatsakanova, M.N.; Vernov, Yu.S.

1997-01-01

The aim of the paper is to describe the historical aspects of the canonical commutation relations (CCR) and to analyse the new results. The CCR are the algebraic structure (Heisenberg algebra) on the basis of quantum mechanics and quantum field theory. The following results are discussed: the Weyl form of CCR, Von Neumann's uniqueness theorem, regularity conditions, CCR representation in standard and Weyl forms, CCR in an indefinite metric space, class of CCR regular representations and CCR in the case of infinite number of degrees of freedom [ru

Euler polynomials and identities for non-commutative operators

Science.gov (United States)

De Angelis, Valerio; Vignat, Christophe

2015-12-01

Three kinds of identities involving non-commutating operators and Euler and Bernoulli polynomials are studied. The first identity, as given by Bender and Bettencourt [Phys. Rev. D 54(12), 7710-7723 (1996)], expresses the nested commutator of the Hamiltonian and momentum operators as the commutator of the momentum and the shifted Euler polynomial of the Hamiltonian. The second one, by Pain [J. Phys. A: Math. Theor. 46, 035304 (2013)], links the commutators and anti-commutators of the monomials of the position and momentum operators. The third appears in a work by Figuieira de Morisson and Fring [J. Phys. A: Math. Gen. 39, 9269 (2006)] in the context of non-Hermitian Hamiltonian systems. In each case, we provide several proofs and extensions of these identities that highlight the role of Euler and Bernoulli polynomials.

Explicitly-correlated ring-coupled-cluster-doubles theory: Including exchange for computations on closed-shell systems

Energy Technology Data Exchange (ETDEWEB)

Hehn, Anna-Sophia; Holzer, Christof; Klopper, Wim, E-mail: klopper@kit.edu

2016-11-10

Highlights: • Ring-coupled-cluster-doubles approach now implemented with exchange terms. • Ring-coupled-cluster-doubles approach now implemented with F12 functions. • Szabo–Ostlund scheme (SO2) implemented for use in SAPT. • Fast convergence to the limit of a complete basis. • Implementation in the TURBOMOLE program system. - Abstract: Random-phase-approximation (RPA) methods have proven to be powerful tools in electronic-structure theory, being non-empirical, computationally efficient and broadly applicable to a variety of molecular systems including small-gap systems, transition-metal compounds and dispersion-dominated complexes. Applications are however hindered due to the slow basis-set convergence of the electron-correlation energy with the one-electron basis. As a remedy, we present approximate explicitly-correlated RPA approaches based on the ring-coupled-cluster-doubles formulation including exchange contributions. Test calculations demonstrate that the basis-set convergence of correlation energies is drastically accelerated through the explicitly-correlated approach, reaching 99% of the basis-set limit with triple-zeta basis sets. When implemented in close analogy to early work by Szabo and Ostlund [36], the new explicitly-correlated ring-coupled-cluster-doubles approach including exchange has the perspective to become a valuable tool in the framework of symmetry-adapted perturbation theory (SAPT) for the computation of dispersion energies of molecular complexes of weakly interacting closed-shell systems.

When is Commuting Desirable to the Individual?

OpenAIRE

Ory, D T; Mokhtarian, Patricia L; Redmond, Lothlorien; Salomon, Ilan; Collantes, G O; Choo, Sangho

2004-01-01

Commuting is popularly viewed as a stressful, costly, time-wasting experience from the individual perspective, with the attendant congestion imposing major social costs as well. However, several authors have noted that commuting can also offer benefits to the individual, serving as a valued transition between the home and work realms of personal life. Using survey data collected from about 1,300 commuting workers in three San Francisco Bay Area neighborhoods, we develop empirical models for f...

P-commutative topological *-algebras

International Nuclear Information System (INIS)

Mohammad, N.; Thaheem, A.B.

1991-07-01

If P(A) denotes the set of all continuous positive functionals on a unital complete Imc *-algebra and S(A) the extreme points of P(A), and if the spectrum of an element χ Ε A coincides with the set {f(χ): f Ε S(A)}, then A is shown to be P-commutative. Moreover, if A is unital symmetric Frechet Q Imc *-algebra, then this spectral condition is, in fact, necessary. Also, an isomorphism theorem between symmetric Frechet P-commutative Imc *-algebras is established. (author). 12 refs

Alternative loop rings

CERN Document Server

Goodaire, EG; Polcino Milies, C

1996-01-01

For the past ten years, alternative loop rings have intrigued mathematicians from a wide cross-section of modern algebra. As a consequence, the theory of alternative loop rings has grown tremendously. One of the main developments is the complete characterization of loops which have an alternative but not associative, loop ring. Furthermore, there is a very close relationship between the algebraic structures of loop rings and of group rings over 2-groups. Another major topic of research is the study of the unit loop of the integral loop ring. Here the interaction between loop rings and group ri

Commuting patterns of workers in a village of Barddhaman district, West Bengal

Directory of Open Access Journals (Sweden)

Bhaswati Mondal

2015-06-01

Full Text Available Commuting helps to keep balance between residence and workplace of workers. With growing accessibility and connectivity, the importance of commuting is increasing all over the world. It is becoming a major substitute to migration. In commute-studies, commute-pattern is an important chapter. It highlights commuters’ directions of movement, distance they cover, modes of transport they use, the time they take to commute, etc. Unlike the urban-based commute pattern, commute pattern in rural areas are relatively an under-researched issue. In fact, traditionally rural people are thought to carry a sedentary lifestyle. Using primary data, this study aims to explore the commute patterns of rural workers located in the village of Gandharbapur of Barddhaman district of West Bengal, India. All the commuters were found to be engaged in non-farm work. Commuters stem from two major groups. One group of commuters is accumulated farm-income induced. They possess sufficient agricultural land. Investing their surplus farm-income, they have established non-farm works. The second group of commuters is poverty-driven. They are landless poor or are marginal farmers and to escape poverty, they have slipped into these works. Located beyond the suburban area (Memari being the nearest town, most commuters commute to nearby rural areas. Due to non-availability of public transport, women commute less than men do. Regular-paid government employees commute longer than other workers commute. The article concludes with a summary of findings and recommendations for further research.

Deformed conformal and super-Poincare symmetries in the non- (anti-) commutative spaces

International Nuclear Information System (INIS)

Banerjee, R.; Lee, C.; Siwach, S.

2006-01-01

Generators of the super-Poincare algebra in the non- (anti-) commutative superspace are represented using appropriate higher derivative operators defined in this quantum superspace. Also discussed are the analogous representations of the conformal and superconformal symmetry generators in the deformed spaces. This construction is obtained by generalizing the recent work of Wess et al. on the Poincare generators in the θ-deformed Minkowski space, or by using the substitution rules we derived on the basis of the phase-space structures of non- (anti-) commutative-space variables. Even with the non-zero deformation parameters the algebras remain unchanged although the comultiplication rules are deformed. The transformation of the fields under deformed symmetry is also discussed. Our construction can be used for systematic development of field theories in the deformed spaces. (orig.)

Warden’s Five-Ring System Theory: Legitimate Wartime Military Targeting or an Increased Potential to Violate the Law and Norms of Expected Behavior?

Science.gov (United States)

2000-04-01

the five-ring system theory that dramatically improves the warfighters ability to systematically identify wartime targets. However, for all of its...acclaim, little has been written about Warden’s five-ring system theory . Even less has been written about the legal and moral implications of using Warden’s theory to identify wartime targets.

2D Toda chain and associated commutator identity

OpenAIRE

Pogrebkov, A. K.

2007-01-01

Developing observation made in \\cite{commut} we show that simple identity of the commutator type on an associative algebra is in one-to-one correspondence to 2D (infinite) Toda chain. We introduce representation of elements of associative algebra that, under some generic conditions, enables derivation of the Toda chain equation and its Lax pair from the given commutator identity.

Existence of stable wormholes on a non-commutative-geometric background in modified gravity

Energy Technology Data Exchange (ETDEWEB)

Zubair, M.; Mustafa, G. [COMSATS, Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); Waheed, Saira [Prince Mohammad Bin Fahd University, Al Khobar (Saudi Arabia); Abbas, G. [The Islamia University of Bahawalpur, Department of Mathematics, Bahawalpur (Pakistan)

2017-10-15

In this paper, we discuss spherically symmetric wormhole solutions in f(R, T) modified theory of gravity by introducing well-known non-commutative geometry in terms of Gaussian and Lorentzian distributions of string theory. For analytic discussion, we consider an interesting model of f(R, T) gravity defined by f(R, T) = f{sub 1}(R) + λT. By taking two different choices for the function f{sub 1}(R), that is, f{sub 1}(R) = R and f{sub 1}(R) = R + αR{sup 2} + γR{sup n}, we discuss the possible existence of wormhole solutions. In the presence of non-commutative Gaussian and Lorentzian distributions, we get exact and numerical solutions for both these models. By taking appropriate values of the free parameters, we discuss different properties of these wormhole models analytically and graphically. Further, using an equilibrium condition, it is found that these solutions are stable. Also, we discuss the phenomenon of gravitational lensing for the exact wormhole model and it is found that the deflection angle diverges at the wormhole throat. (orig.)

Can non-commutativity resolve the big-bang singularity?

Energy Technology Data Exchange (ETDEWEB)

Maceda, M.; Madore, J. [Laboratoire de Physique Theorique, Universite de Paris-Sud, Batiment 211, 91405, Orsay (France); Manousselis, P. [Department of Engineering Sciences, University of Patras, 26110, Patras (Greece); Physics Department, National Technical University, Zografou Campus, 157 80, Zografou, Athens (Greece); Zoupanos, G. [Physics Department, National Technical University, Zografou Campus, 157 80, Zografou, Athens (Greece); Theory Division, CERN, 1211, Geneva 23 (Switzerland)

2004-08-01

A possible way to resolve the singularities of general relativity is proposed based on the assumption that the description of space-time using commuting coordinates is not valid above a certain fundamental scale. Beyond that scale it is assumed that the space-time has non-commutative structure leading in turn to a resolution of the singularity. As a first attempt towards realizing the above programme a modification of the Kasner metric is constructed which is commutative only at large time scales. At small time scales, near the singularity, the commutation relations among the space coordinates diverge. We interpret this result as meaning that the singularity has been completely delocalized. (orig.)

Non-commutative representation for quantum systems on Lie groups

Energy Technology Data Exchange (ETDEWEB)

Raasakka, Matti Tapio

2014-01-27

The topic of this thesis is a new representation for quantum systems on weakly exponential Lie groups in terms of a non-commutative algebra of functions, the associated non-commutative harmonic analysis, and some of its applications to specific physical systems. In the first part of the thesis, after a review of the necessary mathematical background, we introduce a {sup *}-algebra that is interpreted as the quantization of the canonical Poisson structure of the cotangent bundle over a Lie group. From the physics point of view, this represents the algebra of quantum observables of a physical system, whose configuration space is a Lie group. We then show that this quantum algebra can be represented either as operators acting on functions on the group, the usual group representation, or (under suitable conditions) as elements of a completion of the universal enveloping algebra of the Lie group, the algebra representation. We further apply the methods of deformation quantization to obtain a representation of the same algebra in terms of a non-commutative algebra of functions on a Euclidean space, which we call the non-commutative representation of the original quantum algebra. The non-commutative space that arises from the construction may be interpreted as the quantum momentum space of the physical system. We derive the transform between the group representation and the non-commutative representation that generalizes in a natural way the usual Fourier transform, and discuss key properties of this new non-commutative harmonic analysis. Finally, we exhibit the explicit forms of the non-commutative Fourier transform for three elementary Lie groups: R{sup d}, U(1) and SU(2). In the second part of the thesis, we consider application of the non-commutative representation and harmonic analysis to physics. First, we apply the formalism to quantum mechanics of a point particle on a Lie group. We define the dual non-commutative momentum representation, and derive the phase

Non-commutative representation for quantum systems on Lie groups

International Nuclear Information System (INIS)

Raasakka, Matti Tapio

2014-01-01

The topic of this thesis is a new representation for quantum systems on weakly exponential Lie groups in terms of a non-commutative algebra of functions, the associated non-commutative harmonic analysis, and some of its applications to specific physical systems. In the first part of the thesis, after a review of the necessary mathematical background, we introduce a * -algebra that is interpreted as the quantization of the canonical Poisson structure of the cotangent bundle over a Lie group. From the physics point of view, this represents the algebra of quantum observables of a physical system, whose configuration space is a Lie group. We then show that this quantum algebra can be represented either as operators acting on functions on the group, the usual group representation, or (under suitable conditions) as elements of a completion of the universal enveloping algebra of the Lie group, the algebra representation. We further apply the methods of deformation quantization to obtain a representation of the same algebra in terms of a non-commutative algebra of functions on a Euclidean space, which we call the non-commutative representation of the original quantum algebra. The non-commutative space that arises from the construction may be interpreted as the quantum momentum space of the physical system. We derive the transform between the group representation and the non-commutative representation that generalizes in a natural way the usual Fourier transform, and discuss key properties of this new non-commutative harmonic analysis. Finally, we exhibit the explicit forms of the non-commutative Fourier transform for three elementary Lie groups: R d , U(1) and SU(2). In the second part of the thesis, we consider application of the non-commutative representation and harmonic analysis to physics. First, we apply the formalism to quantum mechanics of a point particle on a Lie group. We define the dual non-commutative momentum representation, and derive the phase space path

What interventions increase commuter cycling? A systematic review.

Science.gov (United States)

Stewart, Glenn; Anokye, Nana Kwame; Pokhrel, Subhash

2015-08-14

To identify interventions that will increase commuter cycling. All settings where commuter cycling might take place. Adults (aged 18+) in any country. Individual, group or environmental interventions including policies and infrastructure. A wide range of 'changes in commuter cycling' indicators, including frequency of cycling, change in workforce commuting mode, change in commuting population transport mode, use of infrastructure by defined populations and population modal shift. 12 studies from 6 countries (6 from the UK, 2 from Australia, 1 each from Sweden, Ireland, New Zealand and the USA) met the inclusion criteria. Of those, 2 studies were randomised control trials and the remainder preintervention and postintervention studies. The majority of studies (n=7) evaluated individual-based or group-based interventions and the rest environmental interventions. Individual-based or group-based interventions in 6/7 studies were found to increase commuter cycling of which the effect was significant in only 3/6 studies. Environmental interventions, however, had small but positive effects in much larger but more difficult to define populations. Almost all studies had substantial loss to follow-up. Despite commuter cycling prevalence varying widely between countries, robust evidence of what interventions will increase commuter cycling in low cycling prevalence nations is sparse. Wider environmental interventions that make cycling conducive appear to reach out to hard to define but larger populations. This could mean that environmental interventions, despite their small positive effects, have greater public health significance than individual-based or group-based measures because those interventions encourage a larger number of people to integrate physical activity into their everyday lives. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Commuter Survey-2014

Data.gov (United States)

US Agency for International Development — This dataset is the USAID portion of a larger dataset developed by OMB to better understand and to quanity the carbon footprint of the daily commute of government...

A dynamic parking charge optimal control model under perspective of commuters' evolutionary game behavior

Science.gov (United States)

Lin, XuXun; Yuan, PengCheng

2018-01-01

In this research we consider commuters' dynamic learning effect by modeling the trip mode choice behavior from a new perspective of dynamic evolutionary game theory. We explore the behavior pattern of different types of commuters and study the evolution path and equilibrium properties under different traffic conditions. We further establish a dynamic parking charge optimal control (referred to as DPCOC) model to alter commuters' trip mode choice while minimizing the total social cost. Numerical tests show. (1) Under fixed parking fee policy, the evolutionary results are completely decided by the travel time and the only method for public transit induction is to increase the parking charge price. (2) Compared with fixed parking fee policy, DPCOC policy proposed in this research has several advantages. Firstly, it can effectively turn the evolutionary path and evolutionary stable strategy to a better situation while minimizing the total social cost. Secondly, it can reduce the sensitivity of trip mode choice behavior to traffic congestion and improve the ability to resist interferences and emergencies. Thirdly, it is able to control the private car proportion to a stable state and make the trip behavior more predictable for the transportation management department. The research results can provide theoretical basis and decision-making references for commuters' mode choice prediction, dynamic setting of urban parking charge prices and public transit induction.

Understanding and encouraging cycle commuting in workplace setting: a psychological perspective

OpenAIRE

Van Bekkum, Jennifer Elizabeth

2011-01-01

This thesis considers the roles that social cognitions play in cycle commuting behaviour. Currently in the field of active travel there is a strong drive towards ecological theories, which often focus on the wider environmental factors that influence cycling. However, research into utilitarian cycling and related physical activities suggests that psychological factors also have an important role to play. In light of the current political climate within the UK and the numerous b...

Motivations for active commuting: a qualitative investigation of the period of home or work relocation.

Science.gov (United States)

Jones, Caroline H D; Ogilvie, David

2012-09-11

Promoting walking or cycling to work (active commuting) could help to increase population physical activity levels. According to the habit discontinuity and residential self-selection hypotheses, moving home or workplace is a period when people (re)assess, and may be more likely to change, their travel behavior. Research in this area is dominated by the use of quantitative research methods, but qualitative approaches can provide in-depth insight into the experiences and processes of travel behavior change. This qualitative study aimed to explore experiences and motivations regarding travel behavior around the period of relocation, in an effort to understand how active commuting might be promoted more effectively. Participants were recruited from the Commuting and Health in Cambridge study cohort in the UK. Commuters who had moved home, workplace or both between 2009 and 2010 were identified, and a purposive sample was invited to participate in semi-structured interviews regarding their experiences of, and travel behavior before and after, relocating. A grounded theory approach was taken to analysis. Twenty-six commuters participated. Participants were motivated by convenience, speed, cost and reliability when selecting modes of travel for commuting. Physical activity was not a primary motivation, but incidental increases in physical activity were described and valued in association with active commuting, the use of public transport and the use of park-and-ride facilities. Emphasizing and improving the relative convenience, cost, speed and reliability of active commuting may be a more promising approach to promoting its uptake than emphasizing the health benefits, at least around the time of relocation. Providing good quality public transport and free car parking within walking or cycling distance of major employment sites may encourage the inclusion of active travel in the journey to work, particularly for people who live too far from work to walk or cycle the

Motivations for active commuting: a qualitative investigation of the period of home or work relocation

Directory of Open Access Journals (Sweden)

Jones Caroline HD

2012-09-01

Full Text Available Abstract Background Promoting walking or cycling to work (active commuting could help to increase population physical activity levels. According to the habit discontinuity and residential self-selection hypotheses, moving home or workplace is a period when people (reassess, and may be more likely to change, their travel behavior. Research in this area is dominated by the use of quantitative research methods, but qualitative approaches can provide in-depth insight into the experiences and processes of travel behavior change. This qualitative study aimed to explore experiences and motivations regarding travel behavior around the period of relocation, in an effort to understand how active commuting might be promoted more effectively. Methods Participants were recruited from the Commuting and Health in Cambridge study cohort in the UK. Commuters who had moved home, workplace or both between 2009 and 2010 were identified, and a purposive sample was invited to participate in semi-structured interviews regarding their experiences of, and travel behavior before and after, relocating. A grounded theory approach was taken to analysis. Results Twenty-six commuters participated. Participants were motivated by convenience, speed, cost and reliability when selecting modes of travel for commuting. Physical activity was not a primary motivation, but incidental increases in physical activity were described and valued in association with active commuting, the use of public transport and the use of park-and-ride facilities. Conclusions Emphasizing and improving the relative convenience, cost, speed and reliability of active commuting may be a more promising approach to promoting its uptake than emphasizing the health benefits, at least around the time of relocation. Providing good quality public transport and free car parking within walking or cycling distance of major employment sites may encourage the inclusion of active travel in the journey to work

Non-commutative residue of projections in Boutet de Monvel's calculus

DEFF Research Database (Denmark)

Gaarde, Anders

2007-01-01

Using results by Melo, Nest, Schick, and Schrohe on the K-theory of Boutet de Monvel's calculus of boundary value problems, we show that the non-commutative residue introduced by Fedosov, Golse, Leichtnam, and Schrohe vanishes on projections in the calculus. This partially answers a question raised...... in a recent collaboration with Grubb, namely whether the residue is zero on sectorial projections for boundary value problems: This is confirmed to be true when the sectorial projections is in the calculus....

The equationally-defined commutator a study in equational logic and algebra

CERN Document Server

Czelakowski, Janusz

2015-01-01

This monograph introduces and explores the notions of a commutator equation and the equationally-defined commutator from the perspective of abstract algebraic logic.  An account of the commutator operation associated with equational deductive systems is presented, with an emphasis placed on logical aspects of the commutator for equational systems determined by quasivarieties of algebras.  The author discusses the general properties of the equationally-defined commutator, various centralization relations for relative congruences, the additivity and correspondence properties of the equationally-defined commutator, and its behavior in finitely generated quasivarieties. Presenting new and original research not yet considered in the mathematical literature, The Equationally-Defined Commutator will be of interest to professional algebraists and logicians, as well as graduate students and other researchers interested in problems of modern algebraic logic.

Groups, rings, modules

CERN Document Server

Auslander, Maurice

2014-01-01

This classic monograph is geared toward advanced undergraduates and graduate students. The treatment presupposes some familiarity with sets, groups, rings, and vector spaces. The four-part approach begins with examinations of sets and maps, monoids and groups, categories, and rings. The second part explores unique factorization domains, general module theory, semisimple rings and modules, and Artinian rings. Part three's topics include localization and tensor products, principal ideal domains, and applications of fundamental theorem. The fourth and final part covers algebraic field extensions

Asymptotic behaviour of a non-commutative rational series with a nonnegative linear representation

Directory of Open Access Journals (Sweden)

Philippe Dumas

2007-01-01

Full Text Available We analyse the asymptotic behaviour in the mean of a non-commutative rational series, which originates from differential cryptanalysis, using tools from probability theory, and from analytic number theory. We derive a Fourier representation of a first-order summation function obtained by interpreting this rational series as a non-classical rational sequence via the octal numeration system. The method is applicable to a wide class of sequences rational with respect to a numeration system essentially under the condition that they admit a linear representation with nonnegative coefficients.

The standard model on non-commutative space-time

International Nuclear Information System (INIS)

Calmet, X.; Jurco, B.; Schupp, P.; Wohlgenannt, M.; Wess, J.

2002-01-01

We consider the standard model on a non-commutative space and expand the action in the non-commutativity parameter θ μν . No new particles are introduced; the structure group is SU(3) x SU(2) x U(1). We derive the leading order action. At zeroth order the action coincides with the ordinary standard model. At leading order in θ μν we find new vertices which are absent in the standard model on commutative space-time. The most striking features are couplings between quarks, gluons and electroweak bosons and many new vertices in the charged and neutral currents. We find that parity is violated in non-commutative QCD. The Higgs mechanism can be applied. QED is not deformed in the minimal version of the NCSM to the order considered. (orig.)

The formal theory of Hopf algebras part II: the case of Hopf algebras ...

African Journals Online (AJOL)

The category HopfR of Hopf algebras over a commutative unital ring R is analyzed with respect to its categorical properties. The main results are: (1) For every ring R the category HopfR is locally presentable, it is coreflective in the category of bialgebras over R, over every R-algebra there exists a cofree Hopf algebra. (2) If ...

On derived groups of division rings II

International Nuclear Information System (INIS)

Mahdavi Hezavehi, M.; Akbari Feyzaabaadi, S.; Mehraabaadi, M.; Hajie Abolhassan, H.

1995-05-01

Let D be a division ring with centre F and denote by D' the derived group (commutator subgroup) of D * = D - {0}. It is shown that if each element of D' is algebraic over F, then D is algebraic over F. It is also proved that each finite separable extension of F in D is of the form F(c) for some element c in the derived group D'. Using these results, it is shown that if each element of the derived group D' is of bounded degree over F, then D is finite dimensional over F. (author). 5 refs

The Remainder Theorem and Factor Theorem for Polynomials over Noncommutative Coefficient Rings

Science.gov (United States)

Dobbs, D. E.

2007-01-01

Let R be an associative ring which has a multiplicative identity element but need not be commutative. Let f(X) = a[subscript n]X[superscript n] + a[subscript n-1]X[superscript n-1] + ... + a[subscript 0] [is a member of] R[X] and [alpha] [is a member of] R. It is known that there exist uniquely determined q(X) = b[subscript n-1]X[superscript n-1]…

Associations between active commuting and physical and mental wellbeing.

Science.gov (United States)

Humphreys, David K; Goodman, Anna; Ogilvie, David

2013-08-01

To examine whether a relationship exists between active commuting and physical and mental wellbeing. In 2009, cross-sectional postal questionnaire data were collected from a sample of working adults (aged 16 and over) in the Commuting and Health in Cambridge study. Travel behaviour and physical activity were ascertained using the Recent Physical Activity Questionnaire (RPAQ) and a seven-day travel-to-work recall instrument from which weekly time spent in active commuting (walking and cycling) was derived. Physical and mental wellbeing were assessed using the Medical Outcomes Study Short Form survey (SF-8). Associations were tested using multivariable linear regression. An association was observed between physical wellbeing (PCS-8) score and time spent in active commuting after adjustment for other physical activity (adjusted regression coefficients 0.48, 0.79 and 1.21 for 30-149 min/week, 150-224 min/week and ≥ 225 min/week respectively versus mental wellbeing (MCS-8) (p=0.52). Greater time spent actively commuting is associated with higher levels of physical wellbeing. Longitudinal studies should examine the contribution of changing levels of active commuting and other forms of physical activity to overall health and wellbeing. Copyright © 2013 Elsevier Inc. All rights reserved.

Associations between long commutes and subjective health complaints among railway workers in Norway

Directory of Open Access Journals (Sweden)

Terhi Urhonen

2016-12-01

Full Text Available Commuting is an important aspect of daily life for many employees, but there is little knowledge of how this affects individual commuters' health and well-being. The authors investigated the relationship between commuting and subjective health complaints, using data from a web-based questionnaire. In a sample of 2126 railway employees, 644 (30.3% had long commute times. A 29-item inventory was used to measure the number and degree of the subjective health complaints. Those who commuted 60 min or more each way were characterized by significantly higher numbers and degrees of subjective health complaints compared with their peers with short commutes. The mean number of complaints was 7.5 among the former group and 6.4 for the latter group (p = 0.009. In a regression model, in which the authors controlled for age, gender, education, self-rated health, and coping, the employees with long commutes reported more complaints than those with short commutes. Significant associations were found between those with long commutes and the number and degree of incidences of self-reported musculoskeletal pain, pseudo-neurologic complaints, and gastrointestinal problems. Commuters who had had long commutes for more than 10 years reported more gastrointestinal and musculoskeletal complaints than those with long commutes for less than 2 years. Also, commuters with long commutes spent less time with their families and leisure activities compared with those with short commutes. The authors conclude that the association between long commute times and higher levels of subjective health complaints should attract the attention of transport planners, employers, and public health policymaker.

Use of the Halbach perturbation theory for the multipole design of the ALS storage ring sextupole

Energy Technology Data Exchange (ETDEWEB)

Marks, S. [Lawrence Berkeley Lab., CA (United States)

1995-02-01

The Advanced Light Source (ALS) storage ring sextupole is a unique multi-purpose magnet. It is designed to operate in the primary or sextupole mode and in three auxiliary trim modes: horizontal steering, vertical steering, and skew quadrupole. Klaus Halbach developed a perturbation theory for iron-dominated magnets which provides the basis for this design. Many magnet designers, certainly those who have been exposed to Klaus, are familiar with this theory and have used it for such things as evaluating the effect of assembly alignment errors. The ALS sextupole design process was somewhat novel in its use of the perturbation theory to design essential features of the magnet. In particular, the steering and skew quadrupole functions are produced by violating sextupole symmetry and are thus perturbations of the normal sextupole excitation. The magnet was designed such that all four modes are decoupled and can be excited independently. This paper discusses the use of Halbach`s perturbation theory to design the trim functions and to evaluate the primary asymmetry in the sextupole mode, namely, a gap in the return yoke to accommodate the vacuum chamber. Prototype testing verified all operating modes of the magnet and confirmed the expected performance from calculations based upon the Halbach perturbation theory. A total of 48 sextupole magnets of this design are now installed and operating successfully in the ALS storage ring.

Quantifying commuter exposures to volatile organic compounds

Science.gov (United States)

Kayne, Ashleigh

Motor-vehicles can be a predominant source of air pollution in cities. Traffic-related air pollution is often unavoidable for people who live in populous areas. Commuters may have high exposures to traffic-related air pollution as they are close to vehicle tailpipes. Volatile organic compounds (VOCs) are one class of air pollutants of concern because exposure to VOCs carries risk for adverse health effects. Specific VOCs of interest for this work include benzene, toluene, ethylbenzene, and xylenes (BTEX), which are often found in gasoline and combustion products. Although methods exist to measure time-integrated personal exposures to BTEX, there are few practical methods to measure a commuter's time-resolved BTEX exposure which could identify peak exposures that could be concealed with a time-integrated measurement. This study evaluated the ability of a photoionization detector (PID) to measure commuters' exposure to BTEX using Tenax TA samples as a reference and quantified the difference in BTEX exposure between cyclists and drivers with windows open and closed. To determine the suitability of two measurement methods (PID and Tenax TA) for use in this study, the precision, linearity, and limits of detection (LODs) for both the PID and Tenax TA measurement methods were determined in the laboratory with standard BTEX calibration gases. Volunteers commuted from their homes to their work places by cycling or driving while wearing a personal exposure backpack containing a collocated PID and Tenax TA sampler. Volunteers completed a survey and indicated if the windows in their vehicle were open or closed. Comparing pairs of exposure data from the Tenax TA and PID sampling methods determined the suitability of the PID to measure the BTEX exposures of commuters. The difference between BTEX exposures of cyclists and drivers with windows open and closed in Fort Collins was determined. Both the PID and Tenax TA measurement methods were precise and linear when evaluated in the

Commuting quantum traces: the case of reflection algebras

Energy Technology Data Exchange (ETDEWEB)

Avan, Jean [Laboratory of Theoretical Physics and Modelization, University of Cergy, 5 mail Gay-Lussac, Neuville-sur-Oise, F-95031, Cergy-Pontoise Cedex (France); Doikou, Anastasia [Theoretical Physics Laboratory of Annecy-Le-Vieux, LAPTH, BP 110, Annecy-Le-Vieux, F-74941 (France)

2004-02-06

We formulate a systematic construction of commuting quantum traces for reflection algebras. This is achieved by introducing two dual sets of generalized reflection equations with associated consistent fusion procedures. Products of their respective solutions yield commuting quantum traces.

Commutability of food microbiology proficiency testing samples.

Science.gov (United States)

Abdelmassih, M; Polet, M; Goffaux, M-J; Planchon, V; Dierick, K; Mahillon, J

2014-03-01

Food microbiology proficiency testing (PT) is a useful tool to assess the analytical performances among laboratories. PT items should be close to routine samples to accurately evaluate the acceptability of the methods. However, most PT providers distribute exclusively artificial samples such as reference materials or irradiated foods. This raises the issue of the suitability of these samples because the equivalence-or 'commutability'-between results obtained on artificial vs. authentic food samples has not been demonstrated. In the clinical field, the use of noncommutable PT samples has led to erroneous evaluation of the performances when different analytical methods were used. This study aimed to provide a first assessment of the commutability of samples distributed in food microbiology PT. REQUASUD and IPH organized 13 food microbiology PTs including 10-28 participants. Three types of PT items were used: genuine food samples, sterile food samples and reference materials. The commutability of the artificial samples (reference material or sterile samples) was assessed by plotting the distribution of the results on natural and artificial PT samples. This comparison highlighted matrix-correlated issues when nonfood matrices, such as reference materials, were used. Artificially inoculated food samples, on the other hand, raised only isolated commutability issues. In the organization of a PT-scheme, authentic or artificially inoculated food samples are necessary to accurately evaluate the analytical performances. Reference materials, used as PT items because of their convenience, may present commutability issues leading to inaccurate penalizing conclusions for methods that would have provided accurate results on food samples. For the first time, the commutability of food microbiology PT samples was investigated. The nature of the samples provided by the organizer turned out to be an important factor because matrix effects can impact on the analytical results. © 2013

The standard model on non-commutative space-time

Energy Technology Data Exchange (ETDEWEB)

Calmet, X.; Jurco, B.; Schupp, P.; Wohlgenannt, M. [Sektion Physik, Universitaet Muenchen (Germany); Wess, J. [Sektion Physik, Universitaet Muenchen (Germany); Max-Planck-Institut fuer Physik, Muenchen (Germany)

2002-03-01

We consider the standard model on a non-commutative space and expand the action in the non-commutativity parameter {theta}{sup {mu}}{sup {nu}}. No new particles are introduced; the structure group is SU(3) x SU(2) x U(1). We derive the leading order action. At zeroth order the action coincides with the ordinary standard model. At leading order in {theta}{sup {mu}}{sup {nu}} we find new vertices which are absent in the standard model on commutative space-time. The most striking features are couplings between quarks, gluons and electroweak bosons and many new vertices in the charged and neutral currents. We find that parity is violated in non-commutative QCD. The Higgs mechanism can be applied. QED is not deformed in the minimal version of the NCSM to the order considered. (orig.)

A Panorama of Modern Operator Theory and Related Topics

CERN Document Server

Dym, Harry; Lancaster, Peter

2012-01-01

This book is dedicated to the memory of Israel Gohberg (1928-2009) - one of the great mathematicians of our time - who inspired innumerable fellow mathematicians and directed many students. The volume reflects the wide spectrum of Gohberg's mathematical interests. It consists of more than 25 invited and peer-reviewed original research papers written by his former students, co-authors and friends. Included are contributions to single and multivariable operator theory, commutative and non-commutative Banach algebra theory, the theory of matrix polynomials and analytic vector-valued functions, se

Extreme commutative quantum observables are sharp

International Nuclear Information System (INIS)

Heinosaari, Teiko; Pellonpaeae, Juha-Pekka

2011-01-01

It is well known that, in the description of quantum observables, positive operator valued measures (POVMs) generalize projection valued measures (PVMs) and they also turn out be more optimal in many tasks. We show that a commutative POVM is an extreme point in the convex set of all POVMs if and only if it is a PVM. This results implies that non-commutativity is a necessary ingredient to overcome the limitations of PVMs.

Dimension of ring polymers in bulk studied by Monte-Carlo simulation and self-consistent theory.

Science.gov (United States)

Suzuki, Jiro; Takano, Atsushi; Deguchi, Tetsuo; Matsushita, Yushu

2009-10-14

We studied equilibrium conformations of ring polymers in melt over the wide range of segment number N of up to 4096 with Monte-Carlo simulation and obtained N dependence of radius of gyration of chains R(g). The simulation model used is bond fluctuation model (BFM), where polymer segments bear excluded volume; however, the excluded volume effect vanishes at N-->infinity, and linear polymer can be regarded as an ideal chain. Simulation for ring polymers in melt was performed, and the nu value in the relationship R(g) proportional to N(nu) is decreased gradually with increasing N, and finally it reaches the limiting value, 1/3, in the range of N>or=1536, i.e., R(g) proportional to N(1/3). We confirmed that the simulation result is consistent with that of the self-consistent theory including the topological effect and the osmotic pressure of ring polymers. Moreover, the averaged chain conformation of ring polymers in equilibrium state was given in the BFM. In small N region, the segment density of each molecule near the center of mass of the molecule is decreased with increasing N. In large N region the decrease is suppressed, and the density is found to be kept constant without showing N dependence. This means that ring polymer molecules do not segregate from the other molecules even if ring polymers in melt have the relationship nu=1/3. Considerably smaller dimensions of ring polymers at high molecular weight are due to their inherent nature of having no chain ends, and hence they have less-entangled conformations.

Canonical quantum theory of gravitational field with higher derivatives

International Nuclear Information System (INIS)

Kawasaki, Shoichiro; Kimura, Tadahiko; Kitago, Koichi.

1981-01-01

A renormalizable gravitational theory with higher derivatives is canonically quantized in the Landau gauge. Field equations and various equal-time commutation relations are explicitly given. The main results obtained in this work are 1) the equal-time commutation relations involving b sub(μ) exhibit the tensor-like behaviour and 2) the theory has the 16-dimensional Poincare-like superalgebra. These results are just the same as those discovered by Nakanishi in the Einstein case. (author)

Individual Public Transportation Accessibility is Positively Associated with Self-Reported Active Commuting.

Science.gov (United States)

Djurhuus, Sune; Hansen, Henning Sten; Aadahl, Mette; Glümer, Charlotte

2014-01-01

Active commuters have lower risk of chronic disease. Understanding which of the, to some extent, modifiable characteristics of public transportation that facilitate its use is thus important in a public health perspective. The aim of the study was to examine the association between individual public transportation accessibility and self-reported active commuting, and whether the associations varied with commute distance, age, and gender. Twenty-eight thousand nine hundred twenty-eight commuters in The Capital Region of Denmark reported self-reported time spent either walking or cycling to work or study each day and the distance to work or study. Data were obtained from the Danish National Health Survey collected in February to April 2010. Individual accessibility by public transportation was calculated using a multi-modal network in a GIS. Multilevel logistic regression was used to analyze the association between accessibility, expressed as access area, and being an active commuter. Public transport accessibility area based on all stops within walking and cycling distance was positively associated with being an active commuter. Distance to work, age, and gender modified the associations. Residing within 10 km commute distance and in areas of high accessibility was associated with being an active commuter and meeting the recommendations of physical activity. For the respondents above 29 years, individual public transportation accessibility was positively associated with being an active commuter. Women having high accessibility had significantly higher odds of being an active commuter compared to having a low accessibility. For men, the associations were insignificant. This study extends the knowledge about the driving forces of using public transportation for commuting by examining the individual public transportation accessibility. Findings suggest that transportation accessibility supports active commuting and planning of improved public transit accessibility

Exploring characteristics and motives of long distance commuter cyclists

DEFF Research Database (Denmark)

Hansen, Karsten Bruun; Nielsen, Thomas Alexander Sick

2014-01-01

are very positive about their commute - pointing to positive experiences, better mood, and stress relief as experiences related to their cycle trip to work. Policy support should devote attention to unlocking the potential that may be embedded in individuals combining their exercise and travel time......, commuter cyclists (>5 km from home to work) have more mobility options, higher incomes, and a longer education than other commuter cyclists. The main motive for longer distance cycling is physical exercise, followed by reduced costs and time used for traveling. The long distance commuter cyclists surveyed......, budgets to promote active travel to work as well as the role of psychological benefits as a factor in promoting and sustaining cycling practices....

On tea, donuts and non-commutative geometry

Directory of Open Access Journals (Sweden)

Igor V. Nikolaev

2018-03-01

Full Text Available As many will agree, it feels good to complement a cup of tea by a donut or two. This sweet relationship is also a guiding principle of non-commutative geometry known as Serre Theorem. We explain the algebra behind this theorem and prove that elliptic curves are complementary to the so-called non-commutative tori.

Indefinite-metric quantum field theory of general relativity, 6

International Nuclear Information System (INIS)

Nakanishi, Noboru

1979-01-01

The canonical commutation relations are analyzed in detail in the indefinite-metric quantum field theory of gravity based on the vierbein formalism. It is explicitly verified that the BRS charge, the local-Lorentz-BRS charge and the Poincare generators satisfy the expected commutation relations. (author)

Physics on the fringe smoke rings, circlons, and alternative theories of everything

CERN Document Server

Wertheim, Margaret

2011-01-01

For the past fifteen years, acclaimed science writer Margaret Wertheim has been collecting the works of "outsider physicists," many without formal training and all convinced that they have found true alternative theories of the universe. Jim Carter, the Einstein of outsiders, has developed his own complete theory of matter and energy and gravity that he demonstrates with experiments in his backyard‚ with garbage cans and a disco fog machine he makes smoke rings to test his ideas about atoms. Captivated by the imaginative power of his theories and his resolutely DIY attitude, Wertheim has been following Carter's progress for the past decade. Centuries ago, natural philosophers puzzled out the laws of nature using the tools of observation and experimentation. Today, theoretical physics has become mathematically inscrutable, accessible only to an elite few. In rejecting this abstraction, outsider theorists insist that nature speaks a language we can all understand. Through a profoundly human profile of Jim Ca...

Impact of Distance on Mode of Active Commuting in Chilean Children and Adolescents

Directory of Open Access Journals (Sweden)

Fernando Rodríguez-Rodríguez

2017-11-01

Full Text Available Active commuting could contribute to increasing physical activity. The objective of this study was to characterise patterns of active commuting to and from schools in children and adolescents in Chile. A total of 453 Chilean children and adolescents aged between 10 and 18 years were included in this study. Data regarding modes of commuting and commuting distance was collected using a validated questionnaire. Commuting mode was classified as active commuting (walking and/or cycling or non-active commuting (car, motorcycle and/or bus. Commuting distance expressed in kilometres was categorised into six subgroups (0 to 0.5, 0.6 to 1, 1.1 to 2, 2.1 to 3, 3.1 to 5 and >5 km. Car commuting was the main mode for children (to school 64.9%; from school 51.2% and adolescents (to school 50.2%; from school 24.7%. Whereas public bus commuting was the main transport used by adolescents to return from school. Only 11.0% and 24.8% of children and adolescents, respectively, walk to school. The proportion of children and adolescents who engage in active commuting was lower in those covering longer distances compared to a short distance. Adolescents walked to and from school more frequently than children. These findings show that non-active commuting was the most common mode of transport and that journey distances may influence commuting modes in children and adolescents.

Higher spin gauge theories in any dimension

International Nuclear Information System (INIS)

Vasiliev, M.A.

2004-01-01

Some general properties of higher spin (HS) gauge theories are summarized, with the emphasize on the nonlinear theories in any dimension. The main conclusion is that nonlinear HS theories exist in any dimension. Note that HS gauge symmetries in the nonlinear HS theory differ from the Yang-Mills gauging of the global HS symmetry of a free theory one starts with by HS field strength dependent nonlinear corrections resulting from the partial gauge fixing of spontaneously broken HS symmetries in the extended non-commutative space. The HS geometry is that of the fuzzy hyperboloid in the auxiliary (fiber) non-commutative space. Its radius depends on the Weyl 0-forms which take values in the infinitive-dimensional module dual to the space of single-particle states in the system

On a relation between massive Yang-Mills theories and dual string models

International Nuclear Information System (INIS)

Mickelsson, J.

1983-01-01

The relations between mass terms in Yang-Mills theories, projective representations of the group of gauge transformations, boundary conditions on vector potentials and Schwinger terms in local charge algebra commutation relations are discussed. The commutation relations (with Schwinger terms) are similar to the current algebra commutation relations of the SU(N) extended dual string model. (orig.)

How do motorways shape commuting patterns?

DEFF Research Database (Denmark)

Hovgesen, Henrik Harder; Nielsen, Thomas Alexander Sick

2004-01-01

on urbanization and spatial interaction patterns in the last 20 years. This paper presents results on how the building of the motorway network has shaped spatial interactions patterns in Denmark over a ten year period. The question asked is how travel time reductions and changing motorway access is related...... to change in the commute pattern. And whether the relations between these factors and commuting are a new course of development or a continuation of past trends....

On the development of non-commutative translation-invariant quantum gauge field models

International Nuclear Information System (INIS)

Sedmik, R.I.P.

2009-01-01

Aiming to understand the most fundamental principles of nature one has to approach the highest possible energy scales corresponding to the smallest possible distances - the Planck scale. Historically, three different theoretical fields have been developed to treat the problems appearing in this endeavor: string theory, quantum gravity, and non-commutative (NC) quantum field theory (QFT). The latter was originally motivated by the conjecture that the introduction of uncertainty relations between space-time coordinates introduces a natural energy cutoff, which should render the resulting computations well defined and finite. Despite failing to fulfill this expectation, NC physics is a challenging field of research, which has proved to be a fruitful source for new ideas and methods. Mathematically, non-commutativity is implemented by the so called Weyl quantization, giving rise to a modified product - the Groenewold-Moyal product. It realizes an operator ordering, and allows to work within the well established framework of QFT on non-commutative spaces. The main obstacle of NCQFT is the appearance of singularities being shifted from high to low energies. This effect, being referred to as 'uV/IR mixing', is a direct consequence of the deformation of the product, and inhibits or complicates the direct application of well approved renormalization schemes. In order to remedy this problem, several approaches have been worked out during the past decade which, unfortunately, all have shortcomings such as the breaking of translation invariance or an inappropriate alternation of degrees of freedom. Thence, the resulting theories are either being rendered 'unphysical', or considered a priori to be toy models. Nonetheless, these efforts have helped to analyze the mechanisms leading to uV/IR mixing and finally led to the insight that renormalizability can only be achieved by respecting the inherent connection of long and short distances (scales) of NCQFT in the construction of

MIGRATION OF A MOONLET IN A RING OF SOLID PARTICLES: THEORY AND APPLICATION TO SATURN'S PROPELLERS

International Nuclear Information System (INIS)

Crida, Aurelien; Papaloizou, John C. B.; Rein, Hanno; Charnoz, Sebastien; Salmon, Julien

2010-01-01

Hundred-meter-sized objects have been identified by the Cassini spacecraft in Saturn's A ring through the so-called propeller features they create in the ring. These moonlets should migrate due to their gravitational interaction with the ring; in fact, some orbital variations have been detected. The standard theory of type I migration of planets in protoplanetary disks cannot be applied to the ring system as it is pressureless. Thus, we compute the differential torque felt by a moonlet embedded in a two-dimensional disk of solid particles, with a flat surface density profile, both analytically and numerically. We find that the corresponding migration rate is too small to explain the observed variations of the propeller's orbit in Saturn's A ring. However, local density fluctuations (due to gravity wakes in the marginally gravitationally stable A ring) may exert a stochastic torque on a moonlet. Our simulations show that this torque can be large enough to account for the observations depending on the parameters of the rings. We find that on timescales of several years the migration of propellers is likely to be dominated by stochastic effects (while the former, non-stochastic migration dominates after ∼10 4 -10 5 years). In that case, the migration rates provided by observations so far suggest that the surface density of the A ring should be on the order of 700 kg m -2 . The age of the propellers should not exceed 1-100 million years depending on the dominant migration regime.

PREFACE: Special section on vortex rings Special section on vortex rings

Science.gov (United States)

Fukumoto, Yasuhide

2009-10-01

This special section of Fluid Dynamics Research includes five articles on vortex rings in both classical and quantum fluids. The leading scientists of the field describe the trends in and the state-of-the-art development of experiments, theories and numerical simulations of vortex rings. The year 2008 was the 150th anniversary of 'vortex motion' since Hermann von Helmholtz opened up this field. In 1858, Helmholtz published a paper in Crelle's Journal which put forward the concept of 'vorticity' and made the first analysis of vortex motion. Fluid mechanics before that was limited to irrotational motion. In the absence of vorticity, the motion of an incompressible homogeneous fluid is virtually equivalent to a rigid-body motion in the sense that the fluid motion is determined once the boundary configuration is specified. Helmholtz proved, among other things, that, without viscosity, a vortex line is frozen into the fluid. This Helmholtz's law immediately implies the preservation of knots and links of vortex lines and its implication is enormous. One of the major trends of fluid mechanics since the latter half of the 20th century is to clarify the topological meaning of Helmholtz's law and to exploit it to develop theoretical and numerical methods to find the solutions of the Euler equations and to develop experimental techniques to gain an insight into fluid motion. Vortex rings are prominent coherent structures in a variety of fluid motions from the microscopic scale, through human and mesoscale to astrophysical scales, and have attracted people's interest. The late professor Philip G Saffman (1981) emphasized the significance of studies on vortex rings. One particular motion exemplifies the whole range of problems of vortex motion and is also a commonly known phenomenon, namely the vortex ring or smoke ring. Vortex rings are easily produced by dropping drops of one liquid into another, or by puffing fluid out of a hole, or by exhaling smoke if one has the skill

75 FR 13680 - Commutation of Sentence: Technical Change

Science.gov (United States)

2010-03-23

... Sentence: Technical Change AGENCY: Bureau of Prisons, Justice. ACTION: Interim rule. SUMMARY: This document makes a minor technical change to the Bureau of Prisons (Bureau) regulations on sentence commutation to.... Commutation of Sentence: Technical Change This document makes a minor technical change to the Bureau...

A note on maximal commutators and commutators of maximal functions

Czech Academy of Sciences Publication Activity Database

Agcayazi, M.; Gogatishvili, Amiran; Koca, K.; Mustafayev, R.

2015-01-01

Roč. 67, č. 2 (2015), s. 581-593 ISSN 0025-5645 R&D Projects: GA ČR GA13-14743S; GA ČR GA201/08/0383 Institutional support: RVO:67985840 Keywords : macimal operator * commutator * BMO Subject RIV: BA - General Mathematics Impact factor: 0.524, year: 2015 http://projecteuclid.org/euclid.jmsj/1429624595

Active commuting to school: How far is too far?

LENUS (Irish Health Repository)

Nelson, Norah M

2008-01-01

ABSTRACT: BACKGROUND: Walking and cycling to school provide a convenient opportunity to incorporate physical activity into an adolescent\\'s daily routine. School proximity to residential homes has been identified as an important determinant of active commuting among children. The purpose of this study is to identify if distance is a barrier to active commuting among adolescents, and if there is a criterion distance above which adolescents choose not to walk or cycle. METHODS: Data was collected in 2003-05 from a cross-sectional cohort of 15-17 yr old adolescents in 61 post primary schools in Ireland. Participants self-reported distance, mode of transport to school and barriers to active commuting. Trained researchers took physical measurements of height and weight. The relation between mode of transport, gender and population density was examined. Distance was entered into a bivariate logistic regression model to predict mode choice, controlling for gender, population density socio-economic status and school clusters. RESULTS: Of the 4013 adolescents who participated (48.1% female, mean age 16.02 +\\/- 0.661), one third walked or cycled to school. A higher proportion of males than females commuted actively (41.0 vs. 33.8%, chi2 (1) = 22.21, p < 0.001, r = -0.074). Adolescents living in more densely populated areas had greater odds of active commuting than those in the most sparsely populated areas (chi2 (df = 3) = 839.64, p < 0.001). In each density category, active commuters travelled shorter distances to school. After controlling for gender and population density, a 1-mile increase in distance decreased the odds of active commuting by 71% (chi2 (df = 1) = 2591.86, p < 0.001). The majority of walkers lived within 1.5 miles and cyclists within 2.5 miles. Over 90% of adolescents who perceived distance as a barrier to active commuting lived further than 2.5 miles from school. CONCLUSION: Distance is an important perceived barrier to active commuting and a predictor

The relationship between bicycle commuting and perceived stress: a cross-sectional study.

Science.gov (United States)

Avila-Palencia, Ione; de Nazelle, Audrey; Cole-Hunter, Tom; Donaire-Gonzalez, David; Jerrett, Michael; Rodriguez, Daniel A; Nieuwenhuijsen, Mark J

2017-06-23

Active commuting - walking and bicycling for travel to and/or from work or educational addresses - may facilitate daily, routine physical activity. Several studies have investigated the relationship between active commuting and commuting stress; however, there are no studies examining the relationship between solely bicycle commuting and perceived stress, or studies that account for environmental determinants of bicycle commuting and stress. The current study evaluated the relationship between bicycle commuting, among working or studying adults in a dense urban setting, and perceived stress. A cross-sectional study was performed with 788 adults who regularly travelled to work or study locations (excluding those who only commuted on foot) in Barcelona, Spain. Participants responded to a comprehensive telephone survey concerning their travel behaviour from June 2011 through to May 2012. Participants were categorised as either bicycle commuters or non-bicycle commuters, and (based on the Perceived Stress Scale, PSS-4) as either stressed or non-stressed. Multivariate Poisson regression with robust variance models of stress status based on exposures with bicycle commuting were estimated and adjusted for potential confounders. Bicycle commuters had significantly lower risk of being stressed than non-bicycle commuters (Relative Risk; RR (95% CI)=0.73 (0.60 to 0.89), p=0.001). Bicycle commuters who bicycled 4 days per week (RR (95% CI)=0.42 (0.24 to 0.73), p=0.002) and those who bicycled 5 or more days per week (RR (95% CI)=0.57 (0.42 to 0.77), pstressed than those who bicycled less than 4 days. This relationship remained statistically significant after adjusting for individual and environmental confounders and when using different cut-offs of perceived stress. Stress reduction may be an important consequence of routine bicycle use and should be considered by decision makers as another potential benefit of its promotion. © Article author(s) (or their employer

ANALISIS FAKTOR-FAKTOR YANG MEMPENGARUHI KEPUTUSAN MIGRASI COMMUTER DI KABUPATEN DEMAK

Directory of Open Access Journals (Sweden)

Ahmad Shidiq

2017-06-01

Full Text Available Fenomena migrasi sangat mewarnai di beberapa negara berkembang, termasuk di berbagai daerah di Indonesia. Di Indonesia terutama banyak tenaga kerja yang berasal dari daerah pedesaan mengalir ke daerah perkotaan, Salah satunya dari Kabupaten Demak. Penelitian ini bertujuan untuk mengetahui faktor-faktor yang mempengaruhi keputusan migrasi commuter di Kecamatan Karangtengah Kabupaten Demak antara lain adalah pendapatan pendidikan, pekerjaan daerah asal, jumlah tanggungan serta status perkawinan. Dalam penelitian ini menggunakan data primer melalui instrumen kuesioner terhadap sampel yaitu sebanyak 89 responden, dan menggunakan data sekunder yaitu data dari instansi-instansi terkait serta literatur buku. Penelitian ini dilakukan di Kecamatan Karangtengah Kabupaten Demak. Analisi yang digunakan dalam penelitian ini adalah binary logistic regression. Hasil penelitian menunjukkan bahwa pendapatan berpengaruh negatif dan signifikan terhadap keputusan migrasi commuter, pendidikan berpengaruh positif dan tidak signifikan terhadap keputusan migrasi commuter, pekerjaan di daerah asal berpengaruh positif dan tidak signifikan terhadap keputusan migrasi commuter, jumlah tanggungan daerah asal berpengaruh negatif dan tidak signifikan terhadap keputusan migrasi commuter, status perkawinan berpengaruh positif dan signifikan terhadap keputusan migrasi commuter. The phenomenon of migration is very coloring in some developing countries , including in the various regions in Indonesia . In Indonesia especially many workers coming from rural regions flowed into the urban area, One of Demak District. This study aims to determine the factors that influence the decision of commuter migration in Sub Karangtengah Demak district include the earnings of education, employment areas of origin, number of dependents and marital status. In this research, using primary data through a questionnaire on the sample of 89 respondents, and using secondary data is data from relevant

The university workers' willingness to pay for commuting

NARCIS (Netherlands)

Russo, G.; van Ommeren, J.N.; Rietveld, P.

2012-01-01

Using a dynamic approach, employing data on job mobility, we demonstrate that university workers' marginal willingness to pay for reducing commuting distance is about €0. 25 per kilometre travelled. This corresponds to a marginal willingness to pay for reducing commuting time of about 75 % of the

FET commutated current-FED inverter

Science.gov (United States)

Rippel, Wally E. (Inventor); Edwards, Dean B. (Inventor)

1983-01-01

A shunt switch comprised of a field-effect transistor (Q.sub.1) is employed to commutate a current-fed inverter (10) using thyristors (SCR1, SCR2) or bijunction transistors (Q.sub.2, Q.sub.3) in a full bridge (1, 2, 3, 4) or half bridge (5, 6) and transformer (T.sub.1) configuration. In the case of thyristors, a tapped inverter (12) is employed to couple the inverter to a dc source to back bias the thyristors during commutation. Alternatively, a commutation power supply (20) may be employed for that purpse. Diodes (D.sub.1, D.sub.2) in series with some voltage dropping element (resistor R.sub.12 or resistors R.sub.1, R.sub.2 or Zener diodes D.sub.4, D.sub.5) are connected in parallel with the thyristors in the half bridge and transformer configuration to assure sharing the back bias voltage. A clamp circuit comprised of a winding (18) negatively coupled to the inductor and a diode (D.sub.3) return stored energy from the inductor to the power supply for efficient operation with buck or boost mode.

Topics in string theory

Science.gov (United States)

Jejjala, Vishnumohan

2002-01-01

This Thesis explores aspects of superstring theory on orbifold spaces and applies some of the intuition gleaned from the study of the non-commutative geometry of space-time to understanding the fractional quantum Hall effect. The moduli space of vacua of marginal and relevant deformations of N = 4 super-Yang-Mills gauge theory in four dimensions is interpreted in terms of non-commutative geometry. A formalism for thinking about the algebraic geometry of the moduli space is developed. Within this framework, the representation theory of the algebras studied provides a natural exposition of D-brane fractionation. The non-commutative moduli space of deformations preserving N = 1 supersymmetry is examined in detail through various examples. In string theory, by the AdS/CFT correspondence, deformations of the N = 4 field theory are dual to the near-horizon geometries of D-branes on orbifolds of AdS5 x S 5. The physics of D-branes on the dual AdS backgrounds is explored. Quivers encapsulate the matter content of supersymmetric field theories on the worldvolumes of D-branes at orbifold singularities. New techniques for constructing quivers are presented here. When N is a normal subgroup of a finite group G, the quiver corresponding to fixed points of the orbifold M/G is computed from a G/N action on the quiver corresponding to M/G . These techniques prove useful for constructing non-Abelian quivers and for examining discrete torsion orbifolds. Quivers obtained through our constructions contain interesting low-energy phenomenology. The matter content on a brane at an isolated singularity of the Delta27 orbifold embeds the Standard Model. The symmetries of the quiver require exactly three generations of fields in the particle spectrum. Lepton masses are suppressed relative to quark masses because lepton Yukawa couplings do not appear in the superpotential. Lepton masses are generated through the Kahler potential and are related to the supersymmetry breaking scale. The model

Commutator identities on associative algebras and integrability of nonlinear pde's

OpenAIRE

Pogrebkov, A. K.

2007-01-01

It is shown that commutator identities on associative algebras generate solutions of linearized integrable equations. Next, a special kind of the dressing procedure is suggested that in a special class of integral operators enables to associate to such commutator identity both nonlinear equation and its Lax pair. Thus problem of construction of new integrable pde's reduces to construction of commutator identities on associative algebras.

Quantum theory as an emergent phenomenon the statistical mechanics of matrix models as the precursor of quantum field theory

CERN Document Server

Adler, Stephen L

2004-01-01

Quantum mechanics is our most successful physical theory. However, it raises conceptual issues that have perplexed physicists and philosophers of science for decades. This 2004 book develops an approach, based on the proposal that quantum theory is not a complete, final theory, but is in fact an emergent phenomenon arising from a deeper level of dynamics. The dynamics at this deeper level are taken to be an extension of classical dynamics to non-commuting matrix variables, with cyclic permutation inside a trace used as the basic calculational tool. With plausible assumptions, quantum theory is shown to emerge as the statistical thermodynamics of this underlying theory, with the canonical commutation/anticommutation relations derived from a generalized equipartition theorem. Brownian motion corrections to this thermodynamics are argued to lead to state vector reduction and to the probabilistic interpretation of quantum theory, making contact with phenomenological proposals for stochastic modifications to Schr�...

26 CFR 1.46-11 - Commuter highway vehicles.

Science.gov (United States)

2010-04-01

... Rules for Computing Credit for Investment in Certain Depreciable Property § 1.46-11 Commuter highway... investment under section 46(c)(1) for a qualifying commuter highway vehicle is 100 percent. A qualifying... meets the following requirements: (1) The vehicle is section 38 property in the hands of the taxpayer...

Commutation and Darboux transformation

Indian Academy of Sciences (India)

1College of Military Engineering, Pune 411 031, India. 2Department of ... Liouville equation is a particular application of the commutation method. Darboux ... transformation of a differential operator L, then there exists a differential operator A of.

20 CFR 704.102 - Commutation of payments to aliens and nonresidents.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Commutation of payments to aliens and... LHWCA EXTENSIONS Defense Base Act § 704.102 Commutation of payments to aliens and nonresidents. Authority to commute payments to aliens and nonnationals who are not residents of the United States and...

Impacts of urban sprawl and commuting: A modelling study for Italy

NARCIS (Netherlands)

Travisi, C.M.; Camagni, R.; Nijkamp, P.

2010-01-01

This paper aims to analyse empirically the intricate relationship between urban sprawl and commuting, a process that started a few decades ago in Italy. Using a mobility impact index based on commuting data for 1981 and 1991, we quantify the impact of commuting for seven major Italian urban areas,

Bias Assessment of General Chemistry Analytes using Commutable Samples.

Science.gov (United States)

Koerbin, Gus; Tate, Jillian R; Ryan, Julie; Jones, Graham Rd; Sikaris, Ken A; Kanowski, David; Reed, Maxine; Gill, Janice; Koumantakis, George; Yen, Tina; St John, Andrew; Hickman, Peter E; Simpson, Aaron; Graham, Peter

2014-11-01

Harmonisation of reference intervals for routine general chemistry analytes has been a goal for many years. Analytical bias may prevent this harmonisation. To determine if analytical bias is present when comparing methods, the use of commutable samples, or samples that have the same properties as the clinical samples routinely analysed, should be used as reference samples to eliminate the possibility of matrix effect. The use of commutable samples has improved the identification of unacceptable analytical performance in the Netherlands and Spain. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) has undertaken a pilot study using commutable samples in an attempt to determine not only country specific reference intervals but to make them comparable between countries. Australia and New Zealand, through the Australasian Association of Clinical Biochemists (AACB), have also undertaken an assessment of analytical bias using commutable samples and determined that of the 27 general chemistry analytes studied, 19 showed sufficiently small between method biases as to not prevent harmonisation of reference intervals. Application of evidence based approaches including the determination of analytical bias using commutable material is necessary when seeking to harmonise reference intervals.

Active Commuting: Workplace Health Promotion for Improved Employee Well-Being and Organizational Behavior.

Science.gov (United States)

Page, Nadine C; Nilsson, Viktor O

2016-01-01

Objective: This paper describes a behavior change intervention that encourages active commuting using electrically assisted bikes (e-bikes) for health promotion in the workplace. This paper presents the preliminary findings of the intervention's impact on improving employee well-being and organizational behavior, as an indicator of potential business success. Method: Employees of a UK-based organization participated in a workplace travel behavior change intervention and used e-bikes as an active commuting mode; this was a change to their usual passive commuting behavior. The purpose of the intervention was to develop employee well-being and organizational behavior for improved business success. We explored the personal benefits and organizational co-benefits of active commuting and compared these to a travel-as-usual group of employees who did not change their behavior and continued taking non-active commutes. Results: Employees who changed their behavior to active commuting reported more positive affect, better physical health and more productive organizational behavior outcomes compared with passive commuters. In addition, there was an interactive effect of commuting mode and commuting distance: a more frequent active commute was positively associated with more productive organizational behavior and stronger overall positive employee well-being whereas a longer passive commute was associated with poorer well-being, although there was no impact on organizational behavior. Conclusion: This research provides emerging evidence of the value of an innovative workplace health promotion initiative focused on active commuting in protecting and improving employee well-being and organizational behavior for stronger business performance. It considers the significant opportunities for organizations pursuing improved workforce well-being, both in terms of employee health, and for improved organizational behavior and business success.

Income, Wealth and Consumption of Cross-Border Commuters to Luxembourg

OpenAIRE

Thomas Y. Mathä; Alessandro Porpiglia; Michael Ziegelmeyer

2012-01-01

Exceeding 40% of domestic employment cross-border commuters are extremely important to Luxembourg's economy and labour market in general. This paper presents unique information on their income, wealth and consumption using representative survey data from cross-border commuter households to Luxembourg. The estimated average total net wealth of cross-border commuter households is about EUR 240,000, which falls substantially short of comparable estimates for Luxembourg resident households exceed...

(Non-)commutative closed string on T-dual toroidal backgrounds

CERN Document Server

Andriot, David; Lust, Dieter; Patalong, Peter

2013-01-01

In this paper we investigate the connection between (non-)geometry and (non-)commutativity of the closed string. To this end, we solve the classical string on three T-dual toroidal backgrounds: a torus with H-flux, a twisted torus and a non-geometric background with Q-flux. In all three situations we work under the assumption of a dilute flux and consider quantities to linear order in the flux density. Furthermore, we perform the first steps of a canonical quantization for the twisted torus, to derive commutators of the string expansion modes. We use them as well as T-duality to determine, in the non-geometric background, a commutator of two string coordinates, which turns out to be non-vanishing. We relate this non-commutativity to the closed string boundary conditions, and the non-geometric Q-flux.

Understanding adolescents' intentions to commute by car or bicycle as adults

DEFF Research Database (Denmark)

Sigurdardottir, Sigrun Birna; Kaplan, Sigal; Møller, Mette

2013-01-01

This study focuses on the intentions of adolescents to commute by car or bicycle as adults. The behavioral model is based on intrapersonal and interpersonal constructs from the theory of planned behavior extended to include constructs from the institutional, community and policy domains. Data from...... a survey among Danish adolescents is analyzed. It is found that car use intentions are related to positive car passenger experience, general interest in cars, and car ownership norms, and are negatively related to willingness to accept car restrictions and perceived lack of behavioral control. Cycling...

Newton's second law in a non-commutative space

International Nuclear Information System (INIS)

Romero, Juan M.; Santiago, J.A.; Vergara, J. David

2003-01-01

In this Letter we show that corrections to Newton's second law appear if we assume a symplectic structure consistent with the commutation rules of the non-commutative quantum mechanics. For central field we find that the correction term breaks the rotational symmetry. For the Kepler problem, this term is similar to a Coriolis force

Modelling the relation between income and commuting distance

DEFF Research Database (Denmark)

Carra, Giulia; Mulalic, Ismir; Fosgerau, Mogens

2016-01-01

We discuss the distribution of commuting distances and its relation to income. Using data from Denmark, the UK and the USA, we show that the commuting distance is (i) broadly distributed with a slow decaying tail that can be fitted by a power law with exponent γ ≈ 3 and (ii) an average growing...

Algebras, rings and modules

CERN Document Server

Hazewinkel, Michiel; Kirichenko, V V

Provides both the classical aspects of the theory of groups and their representations as well as a general introduction to the modern theory of representations, including the representations of quivers and finite partially ordered sets. This volume provides the theory of semiprime Noetherian semiperfect and semidistributive rings.

Topological matter, integrable models and fusion rings

International Nuclear Information System (INIS)

Nemeschansky, D.; Warner, N.P.

1992-01-01

We show how topological G k /G k models can be embedded into the topological matter models that are obtained by perturbing the twisted N = 2 supersymmetric, hermitian symmetric, coset models. In particular, this leads to an embedding of the fusion ring of G as a sub-ring of the perturbed, chiral primary ring. The perturbation of the twisted N = 2 model that leads to the fusion ring is also shown to lead to an integrable N = 2 supersymmetric field theory when the untwisted N = 2 superconformal field theory is perturbed by the same operator and its hermitian conjugate. (orig.)

Commutators of Integral Operators with Variable Kernels on Hardy ...

Indian Academy of Sciences (India)

Home; Journals; Proceedings – Mathematical Sciences; Volume 115; Issue 4. Commutators of Integral Operators with Variable Kernels on Hardy Spaces. Pu Zhang Kai Zhao. Volume 115 Issue 4 November 2005 pp 399-410 ... Keywords. Singular and fractional integrals; variable kernel; commutator; Hardy space.

High Speed Rail commuting: Efficiency analysis of the Spanish HSR links

Energy Technology Data Exchange (ETDEWEB)

Moyano, A.

2016-07-01

This paper is centred on the analysis of the commuting High Speed Rail (HSR) links that are possible nowadays in the Spanish network. The large development of the network multiplies the possibilities of travelling for commuting. However, not only the feasibility but also the characteristics of the trip, in terms of ticket cost and time spent on the travel, become essential factors when considering HSR commuting links. This paper presents a person-based methodology focused on travellers’ needs and working schedules constraints, which allow differentiating among connections and identifying those intervals of time spent and costs that are affordable for commuting. (Author)

Economic, social, energy and environmental assessment of inter-municipality commuting: The case of Portugal

International Nuclear Information System (INIS)

Ferreira, João-Pedro; Barata, Eduardo; Ramos, Pedro Nogueira; Cruz, Luis

2014-01-01

Commuting is one of the main contributors to the high energy consumption patterns in modern economies. The need to reduce the energy spent in commuting has attracted the attention of academics and policy makers. The main goal of this research is to improve knowledge of the economic, social, energy and environmental opportunity costs of inter-municipality commuting and to support policy-oriented strategies that explicitly take them into account. For this, we use hypothetical assumptions based on the baseline scenario that Portuguese households do not travel between municipalities for commuting purposes coupled with the expected changes in private final consumption. Accordingly, the direct, indirect and induced opportunity costs of inter-municipality commuting are assessed using an input–output model. The significance of the estimated virtual net benefits of commuting is analyzed according to their macroeconomic (GVA, taxes, international imports and employment), energy (primary energy consumption) and environmental (CO 2 emissions) dimensions. The results obtained empirically indicate that inter-municipality commuting has significant opportunity costs in the GVA and GDP as well as in primary energy consumption and CO 2 emissions. The results also indicate that commuters in metropolitan regions and long-distance commuters are responsible for a major share of these opportunity costs. - Highlights: • This paper provides an insight into the magnitude of opportunity costs of commuting. • Input–output modeling is valuable to assess changes in final consumption patterns. • About 25% of household's fuel consumption is due to inter-municipality commuting. • Inter-municipality commuting has net negative effects on GDP, GVA and employment. • The main opportunity costs come from metropolitan and long distance commuting

Non-Commutative Mechanics in Mathematical & in Condensed Matter Physics

Directory of Open Access Journals (Sweden)

Peter A. Horváthy

2006-12-01

Full Text Available Non-commutative structures were introduced, independently and around the same time, in mathematical and in condensed matter physics (see Table 1. Souriau's construction applied to the two-parameter central extension of the planar Galilei group leads to the ''exotic'' particle, which has non-commuting position coordinates. A Berry-phase argument applied to the Bloch electron yields in turn a semiclassical model that has been used to explain the anomalous/spin/optical Hall effects. The non-commutative parameter is momentum-dependent in this case, and can take the form of a monopole in momentum space.

Fitness, Fatness and Active School Commuting among Liverpool Schoolchildren

Directory of Open Access Journals (Sweden)

Robert J. Noonan

2017-08-01

Full Text Available This study investigated differences in health outcomes between active and passive school commuters, and examined associations between parent perceptions of the neighborhood environment and active school commuting (ASC. One hundred-ninety-four children (107 girls, aged 9–10 years from ten primary schools in Liverpool, England, participated in this cross-sectional study. Measures of stature, body mass, waist circumference and cardiorespiratory fitness (CRF were taken. School commute mode (active/passive was self-reported and parents completed the neighborhood environment walkability scale for youth. Fifty-three percent of children commuted to school actively. Schoolchildren who lived in more deprived neighborhoods perceived by parents as being highly connected, unaesthetic and having mixed land-use were more likely to commute to school actively (p < 0.05. These children were at greatest risk of being obese and aerobically unfit(p < 0.01. Our results suggest that deprivation may explain the counterintuitive relationship between obesity, CRF and ASC in Liverpool schoolchildren. These findings encourage researchers and policy makers to be equally mindful of the social determinants of health when advocating behavioral and environmental health interventions. Further research exploring contextual factors to ASC, and examining the concurrent effect of ASC and diet on weight status by deprivation is needed.

Survey of how staff commute to work

CERN Multimedia

2014-01-01

A survey was initiated by the Canton of Geneva (Direction Générale des Transports) and the Swiss Permanent Mission to the United Nations, and is aimed at better understanding how staff in International Organisations commute to/from work so as to better plan future works (road access, public transport, etc.). The ILO, WHO, UNAIDs, Global Fund, IFRC, CERN and UNOG are taking part in this important survey.   People living in Switzerland or France are invited to respond to this survey. The purpose of this survey is to better understand: - your commuting habits, - your willingness to explore alternative commuting options, - your expectations and needs. All data provided to this external company (www.mobilidee.ch) will be kept confidential and will only be used for this particular study. CERN has received all guarantees of confidentiality from this company. Many thanks for your collaboration! GS Department

What Factors Explain Bicycling and Walking for Commuting by ELSA-Brasil Participants?

Science.gov (United States)

de Matos, Sheila Maria Alvim; Pitanga, Francisco José Gondim; Almeida, Maria da Conceição C; Queiroz, Ciro Oliveira; Dos Santos, Clarice Alves; de Almeida, Rogerio Tosta; da Silva, Ianne Tayrine Martins; Griep, Rosane Harter; Amorim, Leila Denise Alves Ferreira; Patrão, Ana Luísa; Aquino, Estela M L

2018-03-01

To analyze the factors associated with commuting by bicycling and walking in adult participants from ELSA-Brasil (Longitudinal Study of Adult Health). Cross-sectional. Six teaching/research institutions throughout Brazil. A total of 15 105 civil servants. Commuting by bicycling and walking was analyzed using the long-form International Physical Activity Questionnaire. A hierarchical model containing possible factors associated with commuting by bicycling and walking was constructed. Crude and adjusted odds ratios were calculated using multinomial logistic regression. Considering the 2 forms of commuting, 66% of the participants were being considered inactive or insufficiently active. In women, being "heavier," feeling unsafe practicing physical activity, and being a former smoker were factors negatively associated with commuting by bicycling and walking. In men, active commuting was less common among those who were overweight or had abdominal obesity, those with a negative perception of safety, and those reporting that there was nowhere suitable in the neighborhood to practice physical activity. Obesity and negative perceptions in the neighborhood are associated with inactive or insufficiently active commuting. The relevance of this finding for public health is reinforce developing policies aimed at promoting health in Brazil and in other countries with similar characteristics.

Soft commutated direct current motor [summary of proposed paper

Energy Technology Data Exchange (ETDEWEB)

Hsu, John S.

1998-10-22

A novel soft commutated direct current (DC) motor is introduced. The current of the commutated coil is intentionally drained before the brush disconnects the coil. This prevents the spark generation that normally occurs in conventional DC motors. A similar principle can be applied for DC generators.

Active commuting of the inhabitants of Liberec city in low and high walkability areas

Directory of Open Access Journals (Sweden)

Lukáš Rubín

2015-12-01

Full Text Available Background: Active commuting in terms of everyday transport to school or work can have a significant effect on physical activity. Active commuting can be influenced by the environment, and examples from abroad show that current environmental changes tend mostly to promote passive forms of commuting. A similar situation of decreasing active commuting might be expected in the Czech Republic. However, little information has been published to date about the issue of active commuting among the inhabitants of our country. Objective: The main objective of the present study is to describe the active commuting patterns of the inhabitants of Liberec city in low and high walkability areas. Methods: A total of 23,621 economically active inhabitants or students of Liberec city aged 6-87 years (34.77 ± 14.39 participated in the study. The data about commuting were retrieved from the national Population and Housing Census of 2011. Geographic information systems were used to objectively analyze the built environment and to calculate the walkability index. Results: Active commuting to/from school or work is used by 17.41% of inhabitants. Active commuting is dominated by walking (16.60% as opposed to cycling (0.81%. Inhabitants who lived in high walkability areas were more likely to actively commute than those living in low walkability areas (OR = 1.54; 95% CI [1.41, 1.68]. Conclusions: This study confirmed the findings of international studies about the effect of the built environment on active commuting among Liberec inhabitants. Active commuters are often those living near or in the city center, which is characterized by high walkability. In Liberec city, walking as a means of active commuting significantly prevails over cycling. One of the reasons might be the diverse topography of the city and the insufficiently developed cycling network.

Daily commuting to work is not associated with variables of health.

Science.gov (United States)

Mauss, Daniel; Jarczok, Marc N; Fischer, Joachim E

2016-01-01

Commuting to work is thought to have a negative impact on employee health. We tested the association of work commute and different variables of health in German industrial employees. Self-rated variables of an industrial cohort (n = 3805; 78.9 % male) including absenteeism, presenteeism and indices reflecting stress and well-being were assessed by a questionnaire. Fasting blood samples, heart-rate variability and anthropometric data were collected. Commuting was grouped into one of four categories: 0-19.9, 20-44.9, 45-59.9, ≥60 min travelling one way to work. Bivariate associations between commuting and all variables under study were calculated. Linear regression models tested this association further, controlling for potential confounders. Commuting was positively correlated with waist circumference and inversely with triglycerides. These associations did not remain statistically significant in linear regression models controlling for age, gender, marital status, and shiftwork. No other association with variables of physical, psychological, or mental health and well-being could be found. The results indicate that commuting to work has no significant impact on well-being and health of German industrial employees.

Weak incidence algebra and maximal ring of quotients

Directory of Open Access Journals (Sweden)

Surjeet Singh

2004-01-01

Full Text Available Let X, X′ be two locally finite, preordered sets and let R be any indecomposable commutative ring. The incidence algebra I(X,R, in a sense, represents X, because of the well-known result that if the rings I(X,R and I(X′,R are isomorphic, then X and X′ are isomorphic. In this paper, we consider a preordered set X that need not be locally finite but has the property that each of its equivalence classes of equivalent elements is finite. Define I*(X,R to be the set of all those functions f:X×X→R such that f(x,y=0, whenever x⩽̸y and the set Sf of ordered pairs (x,y with xring of quotients of I*(X,R is discussed. It is shown that the results proved can give a large class of rings whose maximal right ring of quotients need not be isomorphic to its maximal left ring of quotients.

Formal matrices

CERN Document Server

Krylov, Piotr

2017-01-01

This monograph is a comprehensive account of formal matrices, examining homological properties of modules over formal matrix rings and summarising the interplay between Morita contexts and K theory. While various special types of formal matrix rings have been studied for a long time from several points of view and appear in various textbooks, for instance to examine equivalences of module categories and to illustrate rings with one-sided non-symmetric properties, this particular class of rings has, so far, not been treated systematically. Exploring formal matrix rings of order 2 and introducing the notion of the determinant of a formal matrix over a commutative ring, this monograph further covers the Grothendieck and Whitehead groups of rings. Graduate students and researchers interested in ring theory, module theory and operator algebras will find this book particularly valuable. Containing numerous examples, Formal Matrices is a largely self-contained and accessible introduction to the topic, assuming a sol...

Commutative discrete filtering on unstructured grids based on least-squares techniques

International Nuclear Information System (INIS)

Haselbacher, Andreas; Vasilyev, Oleg V.

2003-01-01

The present work is concerned with the development of commutative discrete filters for unstructured grids and contains two main contributions. First, building on the work of Marsden et al. [J. Comp. Phys. 175 (2002) 584], a new commutative discrete filter based on least-squares techniques is constructed. Second, a new analysis of the discrete commutation error is carried out. The analysis indicates that the discrete commutation error is not only dependent on the number of vanishing moments of the filter weights, but also on the order of accuracy of the discrete gradient operator. The results of the analysis are confirmed by grid-refinement studies

Worldline approach to noncommutative field theory

International Nuclear Information System (INIS)

Bonezzi, R; Corradini, O; Viñas, S A Franchino; Pisani, P A G

2012-01-01

The study of the heat-trace expansion in non-commutative field theory has shown the existence of Moyal non-local Seeley–DeWitt coefficients which are related to the UV/IR mixing and manifest, in some cases, the non-renormalizability of the theory. We show that these models can be studied in a worldline approach implemented in phase space and arrive at a master formula for the n-point contribution to the heat-trace expansion. This formulation could be useful in understanding some open problems in this area, as the heat-trace expansion for the non-commutative torus or the introduction of renormalizing terms in the action, as well as for generalizations to other non-local operators. (paper)

Baryon number violation and novel canonical anti-commutation relations

Science.gov (United States)

Fujikawa, Kazuo; Tureanu, Anca

2018-02-01

The possible neutron-antineutron oscillation is described by an effective quadratic Lagrangian analogous to the BCS theory. It is shown that the conventional equal-time anti-commutation relations of the neutron variable n (t , x →) are modified by the baryon number violating terms. This is established by the Bjorken-Johnson-Low prescription and also by the canonical quantization combined with equations of motion. This novel canonical behavior can give rise to an important physical effect, which is illustrated by analyzing the Lagrangian that violates the baryon number but gives rise to the degenerate effective Majorana fermions and thus no neutron-antineutron oscillation. Technically, this model is neatly treated using a relativistic analogue of the Bogoliubov transformation.

Holographic complexity and noncommutative gauge theory

Science.gov (United States)

Couch, Josiah; Eccles, Stefan; Fischler, Willy; Xiao, Ming-Lei

2018-03-01

We study the holographic complexity of noncommutative field theories. The four-dimensional N=4 noncommutative super Yang-Mills theory with Moyal algebra along two of the spatial directions has a well known holographic dual as a type IIB supergravity theory with a stack of D3 branes and non-trivial NS-NS B fields. We start from this example and find that the late time holographic complexity growth rate, based on the "complexity equals action" conjecture, experiences an enhancement when the non-commutativity is turned on. This enhancement saturates a new limit which is exactly 1/4 larger than the commutative value. We then attempt to give a quantum mechanics explanation of the enhancement. Finite time behavior of the complexity growth rate is also studied. Inspired by the non-trivial result, we move on to more general setup in string theory where we have a stack of D p branes and also turn on the B field. Multiple noncommutative directions are considered in higher p cases.

Applications of Soft Union Sets in the Ring Theory

Directory of Open Access Journals (Sweden)

Yongwei Yang

2013-01-01

through discussing quotient soft subsets, an approach for constructing quotient soft union rings is made. Finally, isomorphism theorems of λ,μ-soft union rings related to invariant soft sets are discussed.

Homogeneous Buchberger algorithms and Sullivant's computational commutative algebra challenge

DEFF Research Database (Denmark)

Lauritzen, Niels

2005-01-01

We give a variant of the homogeneous Buchberger algorithm for positively graded lattice ideals. Using this algorithm we solve the Sullivant computational commutative algebra challenge.......We give a variant of the homogeneous Buchberger algorithm for positively graded lattice ideals. Using this algorithm we solve the Sullivant computational commutative algebra challenge....

Non-commutative flux representation for loop quantum gravity

Science.gov (United States)

Baratin, A.; Dittrich, B.; Oriti, D.; Tambornino, J.

2011-09-01

The Hilbert space of loop quantum gravity is usually described in terms of cylindrical functionals of the gauge connection, the electric fluxes acting as non-commuting derivation operators. It has long been believed that this non-commutativity prevents a dual flux (or triad) representation of loop quantum gravity to exist. We show here, instead, that such a representation can be explicitly defined, by means of a non-commutative Fourier transform defined on the loop gravity state space. In this dual representation, flux operators act by sstarf-multiplication and holonomy operators act by translation. We describe the gauge invariant dual states and discuss their geometrical meaning. Finally, we apply the construction to the simpler case of a U(1) gauge group and compare the resulting flux representation with the triad representation used in loop quantum cosmology.

Airpower, Chaos, and Infrastructure: Lords of the Rings

National Research Council Canada - National Science Library

Felker, Edward

1998-01-01

.... It focuses on the third ring (infrastructure) of John A. Warden III's theory of five strategic rings, which the author argues is often neglected in the debate over the importance of leadership (first ring...

Algebra with polynomial commutation relations for Zeeman effect in Coulomb-Dirac field

International Nuclear Information System (INIS)

Karasev, M.V.; Novikova, E.M.

2005-01-01

One studies a model of a particle motion in the field of electromagnetic monopole (the Coulomb-Dirac field) disturbed by homogeneous magnetic and inhomogeneous electric fields. The quantum averaging is followed by occurrence of the integrated system the Hamiltonian of which is represented by the algebra elements with polynomial commutation relations. One forms irreducible representations of the mentioned algebra and its hypergeometric coherent states. One obtains the representation of the eigenfunction of the assumption problem and specifies the asymptotics of eigenvalues in the first order of perturbation theory [ru

Infinite-dimensional Lie algebras in 4D conformal quantum field theory

International Nuclear Information System (INIS)

Bakalov, Bojko; Nikolov, Nikolay M; Rehren, Karl-Henning; Todorov, Ivan

2008-01-01

The concept of global conformal invariance (GCI) opens the way of applying algebraic techniques, developed in the context of two-dimensional chiral conformal field theory, to a higher (even) dimensional spacetime. In particular, a system of GCI scalar fields of conformal dimension two gives rise to a Lie algebra of harmonic bilocal fields, V M (x, y), where the M span a finite dimensional real matrix algebra M closed under transposition. The associative algebra M is irreducible iff its commutant M' coincides with one of the three real division rings. The Lie algebra of (the modes of) the bilocal fields is in each case an infinite-dimensional Lie algebra: a central extension of sp(∞,R) corresponding to the field R of reals, of u(∞, ∞) associated with the field C of complex numbers, and of so*(4∞) related to the algebra H of quaternions. They give rise to quantum field theory models with superselection sectors governed by the (global) gauge groups O(N), U(N) and U(N,H)=Sp(2N), respectively

Linearization of non-commuting operators in the partition function

International Nuclear Information System (INIS)

Ahmed, M.

1983-06-01

A generalization of the Stratonovich-Hubbard scheme for evaluating the grand canonical partition function is given. The scheme involves linearization of products of non-commuting operators using the functional integral method. The non-commutivity of the operators leads to an additional term which can be absorbed in the single-particle Hamiltonian. (author)

NYPA/TH!NK Clean Commute Program Report – Inception Through May 2004

Energy Technology Data Exchange (ETDEWEB)

Don Karner; James Francfort; Randall Solomon

2004-11-01

The Clean Commute Program uses TH!NK city electric vehicles from Ford Motor Company’s electric vehicle group, TH!NK Mobility, to demonstrate the feasibility of using electric vehicles for transportation in urban applications. Suburban New York City railroad commuters use the TH!NK city vehicles to commute from their private residences to railroad stations, where they catch commuter trains into New York City. Electric vehicle charging infrastructure for the TH!NK city vehicles is located at the commuters’ private residences as well as seven train stations. Ford leased 97 TH!NK city electric vehicles to commuters from Westchester, Putnam, Rockland, Queens, Nassau, and Suffolk counties for $199 per month per vehicle. The first Clean Commute Program vehicle deliveries occurred late in 2001, with data collection commencing in February 2002. Through May 2004, 24 of the lessees have returned their vehicles to Ford and no longer participate in the Clean Commute Program. Reasons given for returning the vehicles include relocation out of the Program area, change in employment status, change in commuting status, and, in a few cases, dissatisfaction with the vehicle. Additionally, 13 vehicles have been returned to Ford as their leases have completed. In August 2002, Ford announced that it was ceasing production of the TH!NK city and would not extend any TH!NK city leases. Through May 2004, participants in the Clean Commute Program have driven their vehicles over 370,000 miles, avoiding the use of over 17,000 gallons of gasoline. The TH!NK city vehicles are driven an average of between 180 and 230 miles per month, and over 95% of all trips taken with the TH!NK city vehicles replace trips previously taken in gasoline vehicles. This report covers the period from Program inception through May 2004.

MIT employee commuter behavior trial.

Science.gov (United States)

2013-04-01

The objectives of the project included the following: : To evaluate the potential impact (in terms of commuter mode shifts) from the introduction of : disruptive technologies at the Massachusetts Institute of Technology in Cambridge, MA, includin...

Electronically commutated serial-parallel switching for motor windings

Science.gov (United States)

Hsu, John S [Oak Ridge, TN

2012-03-27

A method and a circuit for controlling an ac machine comprises controlling a full bridge network of commutation switches which are connected between a multiphase voltage source and the phase windings to switch the phase windings between a parallel connection and a series connection while providing commutation discharge paths for electrical current resulting from inductance in the phase windings. This provides extra torque for starting a vehicle from lower battery current.

A new non-commutative representation of the Wiener and Poisson processes

International Nuclear Information System (INIS)

Privault, N.

1996-01-01

Using two different constructions of the chaotic and variational calculus on Poisson space, we show that the Wiener and Poisson processes have a non-commutative representation which is different from the one obtained by transfer of the Fock space creation and annihilation operators. We obtain in this way an extension of the non-commutative It calculus. The associated commutation relations show a link between the geometric and exponential distributions. (author). 11 refs

Separable algebras

CERN Document Server

Ford, Timothy J

2017-01-01

This book presents a comprehensive introduction to the theory of separable algebras over commutative rings. After a thorough introduction to the general theory, the fundamental roles played by separable algebras are explored. For example, Azumaya algebras, the henselization of local rings, and Galois theory are rigorously introduced and treated. Interwoven throughout these applications is the important notion of étale algebras. Essential connections are drawn between the theory of separable algebras and Morita theory, the theory of faithfully flat descent, cohomology, derivations, differentials, reflexive lattices, maximal orders, and class groups. The text is accessible to graduate students who have finished a first course in algebra, and it includes necessary foundational material, useful exercises, and many nontrivial examples.

Are workers with a long commute less productive? An empirical analysis of absenteeism

NARCIS (Netherlands)

van Ommeren, J.N.; Gutierrez Puigarnau, E.

2011-01-01

We hypothesise, and test for, a negative effect of the length of the worker's commute on worker's productivity, by examining whether the commute has a positive effect on worker's absenteeism. We identify this effect using employer-induced changes in commuting distance. Our estimates for Germany

Study of the time evolution of correlation functions of the transverse Ising chain with ring frustration by perturbative theory

Science.gov (United States)

Zheng, Zhen-Yu; Li, Peng

2018-04-01

We consider the time evolution of two-point correlation function in the transverse-field Ising chain (TFIC) with ring frustration. The time-evolution procedure we investigated is equivalent to a quench process in which the system is initially prepared in a classical kink state and evolves according to the time-dependent Schrödinger equation. Within a framework of perturbative theory (PT) in the strong kink phase, the evolution of the correlation function is disclosed to demonstrate a qualitatively new behavior in contrast to the traditional case without ring frustration.

Lectures on a theory of computation and complexity over the reals (or an arbitrary ring)

International Nuclear Information System (INIS)

Blum, L.

1990-01-01

These lectures will discuss a new theory of computation and complexity which attempts to integrate key ideas from the classical theory in a setting more amenable to problems defined over continuous domains. The approach taken here is both algebraic and concrete; the underlying space is an arbitrary ring (or field) and the basic operations are polynominal (or rational) maps and tests. This approach yields results in the continuous setting analogous to the pivotal classical results of undecidability and NP-completeness over the integers, yet reflecting the special mathematical character of the underlying space. The goal of these lectures is to highlight key aspects of the new theory as well as to give exposition, in this setting, of classical ideas and results. Indeed, since this new theory is more mathematical, perhaps less dependent on logic than the classical theory, a number of key results have more straightforward and transparent proofs in this setting. One of our themes will be the comparison of results over the integers with results over the reals and complex numbers. Contrasting one theory with the other will help illuminate each, and give deeper understanding to such basic concepts as decidability, definability, computability, and complexity. 53 refs

Migration Dilemmas of Islanders: Commuting Leading to Migration or Remaining at Home

Directory of Open Access Journals (Sweden)

Ivan Lajić

2001-09-01

Full Text Available The paper presents and discusses the results of an empirical survey carried out in April 2000 on the islands Prvić, Zlarin and Krapanj in the Šibenik coastal area. These islands are part of a group of islands marked by the highest rates of depopulation, in which even recently daily commuting was one of the most expressed forms of mechanical population development. Daily commuting is seen as an initial state leading to permanent migration, i.e. to out-migration. Potential migrants become familiar with the social, economic, cultural and other traits of their future destination area, which makes it easier for them to leave their places of origin. Thus, for the purposes of the research, the survey selected a population of daily commuters, mainly young people of working age who usually constitute the segment of the population most Iikely to migrate. The survey used both a questionnaire and interviews. Respondents belonged to two relevant groups of the island population: employees commuting each day to work and pupils commuting daily to school. Even though the sample included practically the entire island population with the given migrational and socio-demographic characteristics, the total number of respondents was still too small for the application of standard methods of statistical analysis. In order to gain better insight into the pre-migrational situation on the islands, a few adult islander commuters were added to the group of commuting employees. The goal of the research was to gain an understanding of commuting phenomena in the island micro-society, especially of the migration dilemmas of young islanders. The most frequent variables in the survey were: island/settlement, gender and school. Commuting between the island and mainland is the dominant form of spatial mobility among islanders and constitutes an essential part of their daily life. The most frequent reasons for commuting among islanders are school attendance, going to work, going

Method for solving quantum field theory in the Heisenberg picture

International Nuclear Information System (INIS)

Nakanishi, Noboru

2004-01-01

This paper is a review of the method for solving quantum field theory in the Heisenberg picture, developed by Abe and Nakanishi since 1991. Starting from field equations and canonical (anti) commutation relations, one sets up a (q-number) Cauchy problem for the totality of d-dimensional (anti) commutators between the fundamental fields, where d is the number of spacetime dimensions. Solving this Cauchy problem, one obtains the operator solution of the theory. Then one calculates all multiple commutators. A representation of the operator solution is obtained by constructing the set of all Wightman functions for the fundamental fields; the truncated Wightman functions are constructed so as to be consistent with all vacuum expectation values of the multiple commutators mentioned above and with the energy-positivity condition. By applying the method described above, exact solutions to various 2-dimensional gauge-theory and quantum-gravity models are found explicitly. The validity of these solutions is confirmed by comparing them with the conventional perturbation-theoretical results. However, a new anomalous feature, called the ''field-equation anomaly'', is often found to appear, and its perturbation-theoretical counterpart, unnoticed previously, is discussed. The conventional notion of an anomaly with respect to symmetry is reconsidered on the basis of the field-equation anomaly, and the derivation of the critical dimension in the BRS-formulated bosonic string theory is criticized. The method outlined above is applied to more realistic theories by expanding everything in powers of the relevant parameter, but this expansion is not equivalent to the conventional perturbative expansion. The new expansion is BRS-invariant at each order, in contrast to that in the conventional perturbation theory. Higher-order calculations are generally extremely laborious to perform explicitly. (author)

Covariant Gauss law commutator anomaly

International Nuclear Information System (INIS)

Dunne, G.V.; Trugenberger, C.A.; Massachusetts Inst. of Tech., Cambridge

1990-01-01

Using a (fixed-time) hamiltonian formalism we derive a covariant form for the anomaly in the commutator algebra of Gauss law generators for chiral fermions interacting with a dynamical non-abelian gauge field in 3+1 dimensions. (orig.)

Weak KAM for commuting Hamiltonians

International Nuclear Information System (INIS)

Zavidovique, M

2010-01-01

For two commuting Tonelli Hamiltonians, we recover the commutation of the Lax–Oleinik semi-groups, a result of Barles and Tourin (2001 Indiana Univ. Math. J. 50 1523–44), using a direct geometrical method (Stoke's theorem). We also obtain a 'generalization' of a theorem of Maderna (2002 Bull. Soc. Math. France 130 493–506). More precisely, we prove that if the phase space is the cotangent of a compact manifold then the weak KAM solutions (or viscosity solutions of the critical stationary Hamilton–Jacobi equation) for G and for H are the same. As a corollary we obtain the equality of the Aubry sets and of the Peierls barrier. This is also related to works of Sorrentino (2009 On the Integrability of Tonelli Hamiltonians Preprint) and Bernard (2007 Duke Math. J. 136 401–20)

20 CFR 725.521 - Commutation of payments; lump sum awards.

Science.gov (United States)

2010-04-01

... present value of future benefit payments commuted, computed at 4 percent true discount compounded annually... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Commutation of payments; lump sum awards. 725.521 Section 725.521 Employees' Benefits EMPLOYMENT STANDARDS ADMINISTRATION, DEPARTMENT OF LABOR...

A non-commutative formula for the isotropic magneto-electric response

International Nuclear Information System (INIS)

Leung, Bryan; Prodan, Emil

2013-01-01

A non-commutative formula for the isotropic magneto-electric response of disordered insulators under magnetic fields is derived using the methods of non-commutative geometry. Our result follows from an explicit evaluation of the Ito derivative with respect to the magnetic field of the non-commutative formula for the electric polarization reported in Schulz-Baldes and Teufel (2012 arXiv:1201.4812v1). The quantization, topological invariance and connection to a second Chern number of the magneto-electric response are discussed in the context of three-dimensional, disordered, time-reversal or inversion symmetric topological insulators. (paper)

Fractional charge and anomalous commutators

International Nuclear Information System (INIS)

Frishman, Y.; Gepner, D.

1983-06-01

Non-integer charges on topological objects in the presence of fermions are further investigated. The connection with anomalous commutators is discussed. The reason for the identical results in two-dimensional solutions and four-dimensional monopoles is pointed out. (author)

Application of Source-Sink Landscape Influence Values to Commuter Traffic: A Case Study of Xiamen Island

OpenAIRE

Tong Wu; Lina Tang; Huaxiang Chen; Ziyan Wang; Quanyi Qiu

2017-01-01

Landscape patterns are closely related to ecological processes. Different spatial scales and research methods may lead to different results. Therefore, it is crucial to choose suitable research methods when studying different landscape patterns and ecological processes. In the present study, the methods of source-sink landscape theory were applied to the interactions between urban landscape characteristics and commuter traffic behavior around the arterial roads in Xiamen Island. After classif...

Opechowski's theorem and commutator groups

International Nuclear Information System (INIS)

Caride, A.O.; Zanette, S.I.

1985-01-01

It is shown that the conditions of application of Opechowski's theorem for double groups of subgroups of O(3) are directly associated to the structure of their commutator groups. Some characteristics of the structure of classes are also discussed. (Author) [pt

Ring aggregation pattern of metro passenger trips: A study using smart card data

Science.gov (United States)

Wang, Ziyang; Hu, Yuxin; Zhu, Peng; Qin, Yong; Jia, Limin

2018-02-01

With the widespread implementation of smart cards and with more travel details being recorded, travel patterns can be studied more precisely and deeply. Although considerable attention has been paid to travel patterns, the relationship between travel patterns and the functional structure of a city is yet to be well understood. In this research, we study this relationship by analysing metro passenger trip data (in Beijing and Shenzhen in China and London in the United Kingdom), and we present two unprecedented findings. First, through averaging, a linear relationship is found to exist between individual travel distance and the distance between the origin and the city centre. The underlying mechanism is a travel pattern we call "ring aggregation", i.e., the daily movement of city passengers is aggregated into a ring (with approximately equal distances to the city centre). Then, for commuting trips, the daily travel pattern can be regarded as switching between the outer residential ring and the inner work ring. Second, this linear relationship and the ring aggregation pattern seem to be exclusive characteristics of metro systems (and may also fit other moderate- and long-distance transportation modes) but do not apply to short-distance transportation modes, such as bicycles and taxis. This finding implies that the ring aggregation pattern is a product of the relationship between travel patterns and the city functional structure at a large scope.

NYPA/TH!NK Clean Commute Program Final Report - Inception through December 2004

Energy Technology Data Exchange (ETDEWEB)

James Francfort; Don Karner

2005-11-01

The Clean Commute Program uses TH!NK city electric vehicles from Ford Motor Company’s electric vehicle group, TH!NK Mobility, to demonstrate the feasibility of using electric transportation in urban applications. Suburban New York City railroad commuters use the TH!NK city vehicles to commute from their private residences to railroad stations, where they catch commuter trains into New York City. Electric vehicle charging infrastructure for the TH!NK city vehicles is located at the commuters’ private residences as well as seven train stations. Ford leased at total of 97 TH!NK city electric vehicles to commuters from Westchester, Putnam, Rockland, Queens, Nassau, and Suffolk counties for $199 per month. First Clean Commute Program vehicle deliveries occurred late in 2001, with data collection commencing in February 2002. Through May, 2004, 24 of the lessees have returned their vehicles to Ford and no longer participate in the Clean Commute Program. Reasons given for leaving the Program include relocation out of the Program area, change in employment status, change in commuting status, and, in a few cases, dissatisfaction with the vehicle. Additionally, 13 vehicles were returned to Ford when the lease was completed. In August 2002, Ford announced that it was ceasing production of the TH!NK city and would not extend any TH!NK city leases. Mileage accumulation dropped in the last quarter of the program as vehicle leases were returned to Ford. The impact of the program overall was significant as participants in the Clean Commute Program drove their vehicles over 406,074 miles, avoiding the use of over 18,887 gallons of gasoline. During the active portion of the program, the TH!NK city vehicles were driven an average of between 180 and 230 miles per month. Over 95% of all trips taken with the TH!NK city vehicles replaced trips previously taken in gasoline vehicles. This report covers the period from Program inception through December 2004.

INdAM Meeting on Homological and Computational Methods in Commutative Algebra

CERN Document Server

Gubeladze, Joseph; Römer, Tim

2017-01-01

This volume collects contributions by leading experts in the area of commutative algebra related to the  INdAM meeting “Homological and Computational Methods in Commutative Algebra” held in Cortona (Italy) from May 30 to  June 3, 2016 . The conference and this volume are dedicated to Winfried Bruns on the occasion of his 70th birthday. In particular, the topics of this book strongly reflect the variety of Winfried Bruns’ research interests and his great impact on commutative algebra as well as its applications to related fields. The authors discuss recent and relevant developments in algebraic geometry, commutative algebra, computational algebra, discrete geometry and homological algebra. The book offers a unique resource, both for young and more experienced researchers seeking comprehensive overviews and extensive bibliographic references.

Associations between active commuting to school and objectively measured physical activity

DEFF Research Database (Denmark)

Børrestad L, Anita Bjørkelund; Ostergaard, Lars; Andersen, Lars Bo

2013-01-01

, b) compare moderate vigorous physical activity (MVPA) among children cycling vs. walking to school, and c) thus calculate possible underestimated MVPA, when using accelerometers to measure commuter cycling. Methods: A total of 78 children, average age 11.4 (SD = 0.5), participated in the study....... Physical activity was measured with cycle computers and accelerometers for 4 days. Mode of commuting and demographic information was self-reported in a questionnaire. Results: Children who reported to cycle to school spent significantly more time cycling than those who walked to school, 53.6 (SD = ± 33......Background: To provide more accurate assessment of commuting behavior and potential health effect, it is important to have accurate methods. Therefore, the current study aimed to a) compare questionnaire reported mode of commuting with objectively measured data from accelerometer and cycle computer...

Analyses of commuting distances and times in the household context: The case of Berlin

OpenAIRE

Beige, Sigrun

2012-01-01

Commuting is the consequence of a spatial discrepancy between the residential and occupational locations. Commuting distance and time are changed either by residential or occupational mobility. Residential locations are by their very nature chosen at the household level. These joint decisions determine commuting distances and times of each employed household member, leading to a sort of commuting collaboration between the spouses. Multiple-earner households have to adapt their residential loc...

The commuter family as a geographical adaptive strategy for the work-family balance

NARCIS (Netherlands)

van der Klis, M.; Karsten, L.

2009-01-01

In this paper we raise the question of how commuter families create a work-family balance in a situation of incongruity of the geographical scales of work and family. Commuter families combine the work location of a commuting parent on the (inter)national scale, with the home-based parent's work

Commuting behaviour and urban form: a longitudinal study of a polycentric urban region in Denmark

DEFF Research Database (Denmark)

Grunfelder, Julien; Nielsen, Thomas Alexander Sick

2012-01-01

is a polycentric urban region in Denmark. Data from the National Transport Survey of Denmark were used for this quantitative analysis and two time periods were selected to highlight any potential changes over time. Empirical findings indicate that urban form and location variables help to explain the three......This paper is an empirical investigation of the relation between urban form and commuting behaviour in a polycentric urban region. It explores to what extent urban form and location variables help to explain commuting time, distance and mode based on an empirical case, East Jutland, which...... selected aspects of commuting. However, urban form variables have greater explanatory power in explaining commuting modes than commuting time and commuting distance. No general trends in commuting were detectable from the data. Finally, the empirical findings revealed specificities of the case study...

The association between access to public transportation and self-reported active commuting.

Science.gov (United States)

Djurhuus, Sune; Hansen, Henning S; Aadahl, Mette; Glümer, Charlotte

2014-12-05

Active commuting provides routine-based regular physical activity which can reduce the risk of chronic diseases. Using public transportation involves some walking or cycling to a transit stop, transfers and a walk to the end location and users of public transportation have been found to accumulate more moderate physical activity than non-users. Understanding how public transportation characteristics are associated with active transportation is thus important from a public health perspective. This study examines the associations between objective measures of access to public transportation and self-reported active commuting. Self-reported time spent either walking or cycling commuting each day and the distance to workplace were obtained for adults aged 16 to 65 in the Danish National Health Survey 2010 (n = 28,928). Access to public transportation measures were computed by combining GIS-based road network distances from home address to public transit stops an integrating their service level. Multilevel logistic regression was used to examine the association between access to public transportation measures and active commuting. Distance to bus stop, density of bus stops, and number of transport modes were all positively associated with being an active commuter and with meeting recommendations of physical activity. No significant association was found between bus services at the nearest stop and active commuting. The results highlight the importance of including detailed measurements of access to public transit in order to identify the characteristics that facilitate the use of public transportation and active commuting.

The Association between Access to Public Transportation and Self-Reported Active Commuting

Directory of Open Access Journals (Sweden)

Sune Djurhuus

2014-12-01

Full Text Available Active commuting provides routine-based regular physical activity which can reduce the risk of chronic diseases. Using public transportation involves some walking or cycling to a transit stop, transfers and a walk to the end location and users of public transportation have been found to accumulate more moderate physical activity than non-users. Understanding how public transportation characteristics are associated with active transportation is thus important from a public health perspective. This study examines the associations between objective measures of access to public transportation and self-reported active commuting. Self-reported time spent either walking or cycling commuting each day and the distance to workplace were obtained for adults aged 16 to 65 in the Danish National Health Survey 2010 (n = 28,928. Access to public transportation measures were computed by combining GIS-based road network distances from home address to public transit stops an integrating their service level. Multilevel logistic regression was used to examine the association between access to public transportation measures and active commuting. Distance to bus stop, density of bus stops, and number of transport modes were all positively associated with being an active commuter and with meeting recommendations of physical activity. No significant association was found between bus services at the nearest stop and active commuting. The results highlight the importance of including detailed measurements of access to public transit in order to identify the characteristics that facilitate the use of public transportation and active commuting.

Commuter exposure to PM2.5, BC, and UFP in six common transport microenvironments in Sacramento, California

Science.gov (United States)

Ham, Walter; Vijayan, Abhilash; Schulte, Nico; Herner, Jorn D.

2017-10-01

This study was designed to estimate and compare the air pollution exposures experienced by commuters in six common transportation modes utilized by California residents, and to evaluate the impact of practical exposure mitigation strategies in reducing commute exposures. We measured concentrations of fine particle matter (PM2.5), black carbon (BC), and ultrafine particles (UFP) for 161 commutes between April 2014 and November 2015 in Sacramento, CA. We collected measurements for six modes including single occupancy vehicles, high occupancy vehicles (multiple occupants), buses, light rail, train, and bicycling. The largest average concentrations for most pollutants were measured during train commutes and the lowest average concentrations were observed during light-rail commutes. Mitigation options were explored for personal vehicles, bicycling, and train commute modes. We found that ventilation settings of personal vehicles can reduce in-vehicle PM2.5, BC, and UFP concentrations by up to 75%. Similarly, bicycle route choice can reduce exposures by 15-75% with the lowest concentrations observed during commutes on dedicated bicycle paths away from traffic sources. Train commuters experienced UFP concentrations an order of magnitude greater when the locomotive engine was pulling the rail cars versus pushing the rail cars. We found that UFP concentrations during bus, bicycling, and train commutes were 1.6-5.3 times greater than personal vehicle commutes, while light rail commutes had 30% lower UFP concentrations than personal vehicle commutes. The largest exposure per mile occurred during bicycle commutes with PM2.5, BC, and UFP exposures of 1.312 μg/mile, 0.097 μg/mile, and 3.0 × 109 particles/mile, respectively. Train commutes experienced the largest exposure per mile of all of the combustion-derived transportation commute modes. BC accounted for 5-20% of total PM mass across all commute modes with an average fraction of ∼7% of PM2.5.

Application of Source-Sink Landscape Influence Values to Commuter Traffic: A Case Study of Xiamen Island

Directory of Open Access Journals (Sweden)

Tong Wu

2017-12-01

Full Text Available Landscape patterns are closely related to ecological processes. Different spatial scales and research methods may lead to different results. Therefore, it is crucial to choose suitable research methods when studying different landscape patterns and ecological processes. In the present study, the methods of source-sink landscape theory were applied to the interactions between urban landscape characteristics and commuter traffic behavior around the arterial roads in Xiamen Island. After classification of land use types using remote sensing images from the IKONOS satellite and ArcGIS software (ESRI, Redlands, CA, USA, the landscape patterns of areas surrounding arterial roads (within 1 km were evaluated using source-sink landscape influence (SLI. The results showed that Xiamen Island’s urban expressway had the highest SLI value (0.191, followed by the state highways (0.067, the provincial highways (0.030, and the county roads (0.025. When considering all road types, the correlation between a road’s SLI value and its commuter traffic flow was 0.684. This result was explained by three observations: (1 The contribution of the core area of each landscape pattern to traffic flow was positively correlated with the traffic flow. (2 Areas surrounding the urban expressway and the state highways had lower values for Shannon’s diversity index, indicating that these areas had a lower degree of landscape fragmentation. (3 The landscape patterns surrounding the urban expressway and the state highways were more concentrated and complex than those around other road types. The application of source-sink landscape pattern theory allows for researchers to integrate the relationships between landscape patterns surrounding roads and commuter traffic flow on those roads and to analyze the reasons for these relationships.

Objective physical activity of filipino youth stratified for commuting mode to school.

Science.gov (United States)

Tudor-Locke, Catrine; Ainsworth, Barbara E; Adair, Linda S; Popkin, Barry M

2003-03-01

The Cebu Longitudinal Health and Nutrition Survey included self-report measures and objective measures (Caltrac accelerometer) of Filipino adolescent (ages 14-16) physical activity (PA) in 1998-99. The purpose of this subanalysis was to compare objectively monitored PA of adolescents who differed by their self-reported habitual commuting mode to school, specifically commuting by walking, motorized transport, or a combination of the two. Descriptive analysis included the proportion of adolescents who reported commuting to school by the different modes, participating in sport/exercise during or after school, or currently working. ANCOVA was used to estimate and compare adjusted mean Caltrac-derived energy expenditure (kcal.d ) by commuting mode for each gender. Covariates were age, weight, and height. The analysis sample of 1518 Filipino adolescents included 691 male (BMI = 18.5 +/- 2.5) and 827 female subjects (BMI = 18.7 +/- 2.3). A total of 323 male subjects (46.8% of all male subjects) walked to school, 160 (23.2%) took motorized transport, and 208 (30.0%) used a combination of the two modes. The corresponding values for female subjects were 303 (36.6%), 177 (21.4%), and 347 (42.0%). The absolute difference in Caltrac-derived energy expenditure that appeared to be due to active commuting was 44.2 kcal.d for Filipino male adolescents and 33.2 kcal.d for female adolescents. These differences between commuting modes could not be explained by participation in sport/exercise or by current employment. Assuming 200 school days in a year, the difference in energy expended due to active commuting translates to a 8840 kcal and 6640 kcal in male and female subjects, respectively. For those youth who commute to school by motorized transport a yearly positive energy balance (i.e., weight gain) of 2-3 lb would be anticipated, all other things being held constant.

Active commuting to school: How far is too far?

Directory of Open Access Journals (Sweden)

Moyna Niall M

2008-01-01

Full Text Available Abstract Background Walking and cycling to school provide a convenient opportunity to incorporate physical activity into an adolescent's daily routine. School proximity to residential homes has been identified as an important determinant of active commuting among children. The purpose of this study is to identify if distance is a barrier to active commuting among adolescents, and if there is a criterion distance above which adolescents choose not to walk or cycle. Methods Data was collected in 2003–05 from a cross-sectional cohort of 15–17 yr old adolescents in 61 post primary schools in Ireland. Participants self-reported distance, mode of transport to school and barriers to active commuting. Trained researchers took physical measurements of height and weight. The relation between mode of transport, gender and population density was examined. Distance was entered into a bivariate logistic regression model to predict mode choice, controlling for gender, population density socio-economic status and school clusters. Results Of the 4013 adolescents who participated (48.1% female, mean age 16.02 ± 0.661, one third walked or cycled to school. A higher proportion of males than females commuted actively (41.0 vs. 33.8%, χ2 (1 = 22.21, p 2 (df = 3 = 839.64, p 2 (df = 1 = 2591.86, p Conclusion Distance is an important perceived barrier to active commuting and a predictor of mode choice among adolescents. Distances within 2.5 miles are achievable for adolescent walkers and cyclists. Alternative strategies for increasing physical activity are required for individuals living outside of this criterion.

Analysis of Subway Interior Noise at Peak Commuter Time.

Science.gov (United States)

Lee, Donguk; Kim, Gibbeum; Han, Woojae

2017-07-01

Although mass transit systems are convenient and efficient for urban people, little attention has been paid to the potential hearing hazard from their noise. The purpose of the current study was to measure and analyze levels of subway interior noise at peak commuter times and to provide information about commuters' daily dose of noise exposure. To measure the subway interior noise, nine subway lines inside Seoul (i.e., lines 1-9) and six lines surrounding the capital city area (i.e., Central, Bundang, Sinbundang, Incheon, Gyeongui, and Gyeongchun) were chosen. The noise was measured and recorded by a sound level meter for two-hour periods in the morning and evening. 1) In the LZeq analysis, the average noise level of all 15 lines was 72.78 dB; the maximum and minimum noise levels were 78.34 and 62.46 dB, respectively. The average noise level of the nine lines inside Seoul was 73.45 dB, which was 1.68-dB louder than that of the six lines surrounding the capital city area. 2) Based on the LZeq analysis of 33 measured frequencies, 12.5 Hz was the highest frequency and 20,000 Hz was the lowest. 3) There was no remarkable difference in the level of subway interior noise between morning and evening peak commuter times. We concluded that the level of subway interior noise was not loud enough for commuters to incur noise-induced hearing loss. Regardless, environmental noise control efforts in the subway system might be needed for commuters who take a subway every day.

Superfield theory and supermatrix model

International Nuclear Information System (INIS)

Park, Jeong-Hyuck

2003-01-01

We study the noncommutative superspace of arbitrary dimensions in a systematic way. Superfield theories on a noncommutative superspace can be formulated in two folds, through the star product formalism and in terms of the supermatrices. We elaborate the duality between them by constructing the isomorphism explicitly and relating the superspace integrations of the star product lagrangian or the superpotential to the traces of the supermatrices. We show there exists an interesting fine tuned commutative limit where the duality can be still maintained. Namely on the commutative superspace too, there exists a supermatrix model description for the superfield theory. We interpret the result in the context of the wave particle duality. The dual particles for the superfields in even and odd spacetime dimensions are D-instantons and D0-branes respectively to be consistent with the T-duality. (author)

Equational theories of tropical sernirings

DEFF Research Database (Denmark)

Aceto, Luca; Esik, Zoltan; Ingolfsdottir, Anna

2003-01-01

examples of such structures are the (max,+) semiring and the tropical semiring. It is shown that none of the exotic semirings commonly considered in the literature has a finite basis for its equations, and that similar results hold for the commutative idempotent weak semirings that underlie them. For each......This paper studies the equational theories of various exotic semirings presented in the literature. Exotic semirings are semirings whose underlying carrier set is some subset of the set of real numbers equipped with binary operations of minimum or maximum as sum, and addition as product. Two prime...... of these commutative idempotent weak semirings, the paper offers characterizations of the equations that hold in them, decidability results for their equational theories, explicit descriptions of the free algebras in the varieties they generate, and relative axiomatization results. Udgivelsesdato: APR 11...

Operator approximant problems arising from quantum theory

CERN Document Server

Maher, Philip J

2017-01-01

This book offers an account of a number of aspects of operator theory, mainly developed since the 1980s, whose problems have their roots in quantum theory. The research presented is in non-commutative operator approximation theory or, to use Halmos' terminology, in operator approximants. Focusing on the concept of approximants, this self-contained book is suitable for graduate courses.

Commutability of possible external quality assessment materials for cardiac troponin measurement.

Directory of Open Access Journals (Sweden)

Shunli Zhang

Full Text Available The measurement of cardiac troponin is crucial in the diagnosis of myocardial infarction. The performance of troponin measurement is most conveniently monitored by external quality assessment (EQA programs. The commutability of EQA samples is often unknown and the effectiveness of EQA programs is limited.Commutability of possible EQA materials was evaluated. Commercial control materials used in an EQA program, human serum pools prepared from patient samples, purified analyte preparations, swine sera from model animals and a set of patient samples were measured for cTnI with 4 assays including Abbott Architect, Beckman Access, Ortho Vitros and Siemens Centaur. The measurement results were logarithm-transformed, and the transformed data for patient samples were pairwise analyzed with Deming regression and 95% prediction intervals were calculated for each pair of assays. The commutability of the materials was evaluated by comparing the logarithmic results of the materials with the limits of the intervals. Matrix-related biases were estimated for noncommutable materials. The impact of matrix-related bias on EQA was analyzed and a possible correction for the bias was proposed.Human serum pools were commutable for all assays; purified analyte preparations were commutable for 2 of the 6 assay pairs; commercial control materials and swine sera were all noncommutable; swine sera showed no reactivity to Vitros assay. The matrix-related biases for noncommutable materials ranged from -83% to 944%. Matrix-related biases of the EQA materials caused major abnormal between-assay variations in the EQA program and correction of the biases normalized the variations.Commutability of materials has major impact on the effectiveness of EQA programs for cTnI measurement. Human serum pools prepared from patient samples are commutable and other materials are mostly noncommutable. EQA programs should include at least one human serum pool to allow proper interpretation of

Optimization of performance and energy efficiency for series hybrid commuter-car; Series hybrid hoshiki no commuter car ni okeru doryoku seino to energy koritsu ni kansuru kosatsu

Energy Technology Data Exchange (ETDEWEB)

Hayashida, M; Narusawa, K [Traffic Safety and Nuisance Research Institute, Tokyo (Japan)

1997-10-01

The purpose of this study is to reveal a proper power system for a miniature vehicle called as `Commuter-car` for short trips in urban areas. Two types of simulated series hybrid commuter-cars were set on bench test systems. In order to have sufficient performance and energy saving, combination of electric motor and reduction gear. regenerative break efficiency and generator power supplying were considered by transient driving experiments. Further, estimation of primary energy consumption of the commuter-car was tried. 7 refs., 13 figs., 2 tabs.

Evidence for Quantisation in Planetary Ring Systems

OpenAIRE

WAYTE, RICHARD

2017-01-01

Absolute radial positions of the main features in Saturn's ring system have been calculated by adapting the quantum theory of atomic spectra. Fine rings superimposed upon broad rings are found to be covered by a harmonic series of the form N α A(r)1/2, where N and A are integers. Fourier analysis of the ring system shows that the spectral amplitude fits a response profile which is characteristic of a resonant system. Rings of Jupiter, Uranus and Neptune also obey the same rules. Involvement o...

Lectures on algebraic system theory: Linear systems over rings

Science.gov (United States)

Kamen, E. W.

1978-01-01

The presentation centers on four classes of systems that can be treated as linear systems over a ring. These are: (1) discrete-time systems over a ring of scalars such as the integers; (2) continuous-time systems containing time delays; (3) large-scale discrete-time systems; and (4) time-varying discrete-time systems.

Modes and Moods of Mobility: Tourists and Commuters

Directory of Open Access Journals (Sweden)

Orvar Löfgren

2015-06-01

Full Text Available What can we learn from comparing different modes and moods of travel, among, for example, tourists and commuters? This paper contrasts these two very different kinds of mobility, and the ways in which they organise both motion and emotion. It is not only a question about how people interact with various systems of transport, but also how materialities and affects work together. An important topic is the question of how people acquire travelling skills. How do they learn to be a tourist or a commuter, to handle a train ride, navigate a transit space, or interact with strangers? A good reason to contrast commuters and tourists is also because they have often been studied within very different research paradigms. How can these different research traditions be put into a dialogue with each other, and help to develop methods for capturing the often elusive ways in which motion and emotion work together?

On the tsunami model of the origin of multi-ring basins

International Nuclear Information System (INIS)

Yue Zengyuan; Zhang Bin; Chen Daohan.

1990-03-01

By use of the theory of shallow water waves generated by an impulsive pressure, the tsunami theory of the origin of multi-ring basins is rediscussed and an approximate formula used for calculating the ring location is derived. From the computed ring spacing of three multi-ring basins on the moon (Orientale, Moscoviense and Serenitatis South), it is shown that the tsunami model can only be applied to the area within the IV ring which signifies the rim of the excavated basin and the end of the fluidized region. In the frame of the tsunami model, no explanation for ring spacing is equally plausible for exterior rings as well as interior ones. (author). 14 refs, 1 tab

Certain number-theoretic episodes in algebra

CERN Document Server

Sivaramakrishnan, R

2006-01-01

Many basic ideas of algebra and number theory intertwine, making it ideal to explore both at the same time. Certain Number-Theoretic Episodes in Algebra focuses on some important aspects of interconnections between number theory and commutative algebra. Using a pedagogical approach, the author presents the conceptual foundations of commutative algebra arising from number theory. Self-contained, the book examines situations where explicit algebraic analogues of theorems of number theory are available. Coverage is divided into four parts, beginning with elements of number theory and algebra such as theorems of Euler, Fermat, and Lagrange, Euclidean domains, and finite groups. In the second part, the book details ordered fields, fields with valuation, and other algebraic structures. This is followed by a review of fundamentals of algebraic number theory in the third part. The final part explores links with ring theory, finite dimensional algebras, and the Goldbach problem.

Fulltext PDF

Indian Academy of Sciences (India)

all polynomials in a variable X with coefficients in any commutative ring A is itself a ... integers denoted by Z[i] where i is a fixed square root of. -1 in C. The Gaussian ... aim of algebraic number theory is to understand how usual prime numbers ...

Exact-exchange spin-density functional theory of Wigner localization and phase transitions in quantum rings.

Science.gov (United States)

Arnold, Thorsten; Siegmund, Marc; Pankratov, Oleg

2011-08-24

We apply exact-exchange spin-density functional theory in the Krieger-Li-Iafrate approximation to interacting electrons in quantum rings of different widths. The rings are threaded by a magnetic flux that induces a persistent current. A weak space and spin symmetry breaking potential is introduced to allow for localized solutions. As the electron-electron interaction strength described by the dimensionless parameter r(S) is increased, we observe-at a fixed spin magnetic moment-the subsequent transition of both spin sub-systems from the Fermi liquid to the Wigner crystal state. A dramatic signature of Wigner crystallization is that the persistent current drops sharply with increasing r(S). We observe simultaneously the emergence of pronounced oscillations in the spin-resolved densities and in the electron localization functions indicating a spatial electron localization showing ferrimagnetic order after both spin sub-systems have undergone the Wigner crystallization. The critical r(S)(c) at the transition point is substantially smaller than in a fully spin-polarized system and decreases further with decreasing ring width. Relaxing the constraint of a fixed spin magnetic moment, we find that on increasing r(S) the stable phase changes from an unpolarized Fermi liquid to an antiferromagnetic Wigner crystal and finally to a fully polarized Fermi liquid. © 2011 IOP Publishing Ltd

Processing Information in Quantum Decision Theory

OpenAIRE

Yukalov, V. I.; Sornette, D.

2008-01-01

A survey is given summarizing the state of the art of describing information processing in Quantum Decision Theory, which has been recently advanced as a novel variant of decision making, based on the mathematical theory of separable Hilbert spaces. This mathematical structure captures the effect of superposition of composite prospects, including many incorporated intended actions. The theory characterizes entangled decision making, non-commutativity of subsequent decisions, and intention int...

Unity from duality: gravity, gauge theory and strings

International Nuclear Information System (INIS)

Bachas, C.; Bilal, A.; Douglas, M.; Nekrasov, N.; David, F.

2002-01-01

The 76. session of the summer school in theoretical physics was devoted to recent developments in string theory, gauge theories and quantum gravity. Superstring theory is the leading candidate for a unified theory of all fundamental physical forces and elementary particles. The discovery of dualities and of important tools such as D-branes, has greatly reinforced this point of view. This document gathers the papers of 9 lectures: 1) supergravity, 2) supersymmetric gauge theories, 3) an introduction to duality symmetries, 4) large N field theories and gravity, 5) D-branes on the conifold and N = 1 gauge/gravity dualities, 6) de Sitter space, 7) string compactification with N = 1 supersymmetry, 8) open strings and non-commutative gauge theories, and 9) condensates near the Argyres-Douglas point in SU(2) gauge theory with broken N = 2 supersymmetry, and of 8 seminars: 1) quantum field theory with extra dimensions, 2) special holonomy spaces and M-theory, 3) four dimensional non-critical strings, 4) U-opportunities: why ten equal to ten?, 5) exact answers to approximate questions - non-commutative dipoles, open Wilson lines and UV-IR duality, 6) open-string models with broken supersymmetry, 7) on a field theory of open strings, tachyon condensation and closed strings, and 8) exceptional magic. (A.C.)

A new method of converter transformer protection without commutation failure

Science.gov (United States)

Zhang, Jiayu; Kong, Bo; Liu, Mingchang; Zhang, Jun; Guo, Jianhong; Jing, Xu

2018-01-01

With the development of AC / DC hybrid transmission technology, converter transformer as nodes of AC and DC conversion of HVDC transmission technology, its reliable safe and stable operation plays an important role in the DC transmission. As a common problem of DC transmission, commutation failure poses a serious threat to the safe and stable operation of power grid. According to the commutation relation between the AC bus voltage of converter station and the output DC voltage of converter, the generalized transformation ratio is defined, and a new method of converter transformer protection based on generalized transformation ratio is put forward. The method uses generalized ratio to realize the on-line monitoring of the fault or abnormal commutation components, and the use of valve side of converter transformer bushing CT current characteristics of converter transformer fault accurately, and is not influenced by the presence of commutation failure. Through the fault analysis and EMTDC/PSCAD simulation, the protection can be operated correctly under the condition of various faults of the converter.

The Saturnian rings

International Nuclear Information System (INIS)

Alfven, H.

1975-09-01

The structure of the Saturnian rings is traditionally believed to be due to resonances caused by Mimas (and possibly other satellites). It is shown that both theoretical and observational evidence rule out this interpretation. The increased observational accuracy on one hand and the increased understanding of the cosmogonic processes on the other makes it possible to explain the structure of the ring system as a product of condensation from a partially corotating plasma. In certain respects the agreement between theory and observations is about 1%. (Auth.)

Duality and braiding in twisted quantum field theory

International Nuclear Information System (INIS)

Riccardi, Mauro; Szabo, Richard J.

2008-01-01

We re-examine various issues surrounding the definition of twisted quantum field theories on flat noncommutative spaces. We propose an interpretation based on nonlocal commutative field redefinitions which clarifies previously observed properties such as the formal equivalence of Green's functions in the noncommutative and commutative theories, causality, and the absence of UV/IR mixing. We use these fields to define the functional integral formulation of twisted quantum field theory. We exploit techniques from braided tensor algebra to argue that the twisted Fock space states of these free fields obey conventional statistics. We support our claims with a detailed analysis of the modifications induced in the presence of background magnetic fields, which induces additional twists by magnetic translation operators and alters the effective noncommutative geometry seen by the twisted quantum fields. When two such field theories are dual to one another, we demonstrate that only our braided physical states are covariant under the duality

Workers' marginal costs of commuting

DEFF Research Database (Denmark)

van Ommeren, Jos; Fosgerau, Mogens

2009-01-01

This paper applies a dynamic search model to estimate workers' marginal costs of commuting, including monetary and time costs. Using data on workers' job search activity as well as moving behaviour, for the Netherlands, we provide evidence that, on average, workers' marginal costs of one hour...

Field theoretical construction of an infinite set of quantum commuting operators related with soliton equations

International Nuclear Information System (INIS)

Sasaki, Ryu; Yamanaka, Itaru

1987-01-01

The quantum version of an infinite set of polynomial conserved quantities of a class of soliton equations is discussed from the point of view of naive continuum field theory. By using techniques of two dimensional field theories, we show that an infinite set of quantum commuting operators can be constructed explicitly from the knowledge of its classical counterparts. The quantum operators are so constructed as to coincide with the classical ones in the ℎ → 0 limit (ℎ; Planck's constant divided by 2π). It is expected that the explicit forms of these operators would shed some light on the structure of the infinite dimensional Lie algebras which underlie a certain class of quantum integrable systems. (orig.)

Field theoretical construction of an infinite set of quantum commuting operators related with soliton equations

International Nuclear Information System (INIS)

Sasaki, Ryu; Yamanaka, Itaru.

1986-08-01

The quantum version of an infinite set of polynomial conserved quantities of a class of soliton equations is discussed from the point of view of naive continuum field theory. By using techniques of two dimensional field theories, we show that an infinite set of quantum commuting operators can be constructed explicitly from the knowledge of its classical counterparts. The quantum operators are so constructed as to coincide with the classical ones in the ℎ → 0 limit (ℎ; Planck's constant divided by 2π). It is expected that the explicit forms of these operators would shed some light on the structure of the infinite dimensional Lie algebras which underlie certain class of quantum integrable systems. (author)

Wages and commuting: quasi-natural experiments' evidence from firms that relocate

NARCIS (Netherlands)

Mulalic, I.; van Ommeren, J.N.; Pilegaard, N.

2014-01-01

We examine individual-level compensating differentials for commuting distance in a quasi-natural experiment setting by examining how wages respond to changes in commuting distance induced by firm relocations. This set-up enables us to test for the relevance of job search frictions within labour

Wages and commuting: quasi-natural experiments' evidence from firms that relocate

DEFF Research Database (Denmark)

Mulalic, Ismir; N. Van Ommeren, Jos; Pilegaard, Ninette

We examine workers' compensating differentials for commuting distance in a quasi-natural experiment setting by examining how wages of workers belonging to the same firm respond to changes in commuting distance induced by firm relocations. This setup enables us to test for the relevance of non...... explanations. We focus on wage changes in the year after, as well as three years after, the firm relocation. We demonstrate that a one km increase in commuting distance induces a wage increase of only 0.06 percent in the year after the relocation, but a more substantial wage increase of about 0.2 percent three...

WAGES AND COMMUTING: QUASI-NATURAL EXPERIMENTS’ EVIDENCE FROM FIRMS THAT RELOCATE

DEFF Research Database (Denmark)

Mulalic, Ismir; N. Van Ommeren, Jos; Pilegaard, Ninette

2014-01-01

We examine individual-level compensating differentials for commuting distance in a quasi-natural experiment setting by examining how wages respond to changes in commuting distance induced by firm relocations. This set-up enables us to test for the relevance of job search frictions within labour...... market models. Due to the quasi-experimental set-up, we are able to avoid a range of endogeneity issues. We demonstrate that a 1 km increase in commuting distance induces an almost negligible wage increase in the year after the relocation but a more substantial wage increase of about 0.15% three years...

Wages and commuting: quasi-natural experiments' evidence from firms that relocate

DEFF Research Database (Denmark)

Mulalic, Ismir; N. Van Ommeren, Jos; Pilegaard, Ninette

2014-01-01

We examine individual-level compensating differentials for commuting distance in a quasi-natural experiment setting by examining how wages respond to changes in commuting distance induced by firm relocations. This set-up enables us to test for the relevance of job search frictions within labour...... market models. Due to the quasi-experimental set-up, we are able to avoid a range of endogeneity issues. We demonstrate that a 1 km increase in commuting distance induces an almost negligible wage increase in the year after the relocation but a more substantial wage increase of about 0.15% three years...

Quantum groups, non-commutative differential geometry and applications

International Nuclear Information System (INIS)

Schupp, P.; California Univ., Berkeley, CA

1993-01-01

The topic of this thesis is the development of a versatile and geometrically motivated differential calculus on non-commutative or quantum spaces, providing powerful but easy-to-use mathematical tools for applications in physics and related sciences. A generalization of unitary time evolution is proposed and studied for a simple 2-level system, leading to non-conservation of microscopic entropy, a phenomenon new to quantum mechanics. A Cartan calculus that combines functions, forms, Lie derivatives and inner derivations along general vector fields into one big algebra is constructed for quantum groups and then extended to quantum planes. The construction of a tangent bundle on a quantum group manifold and an BRST type approach to quantum group gauge theory are given as further examples of applications. The material is organized in two parts: Part I studies vector fields on quantum groups, emphasizing Hopf algebraic structures, but also introducing a ''quantum geometric'' construction. Using a generalized semi-direct product construction we combine the dual Hopf algebras A of functions and U of left-invariant vector fields into one fully bicovariant algebra of differential operators. The pure braid group is introduced as the commutant of Δ(U). It provides invariant maps A → U and thereby bicovariant vector fields, casimirs and metrics. This construction allows the translation of undeformed matrix expressions into their less obvious quantum algebraic counter parts. We study this in detail for quasitriangular Hopf algebras, giving the determinant and orthogonality relation for the ''reflection'' matrix. Part II considers the additional structures of differential forms and finitely generated quantum Lie algebras -- it is devoted to the construction of the Cartan calculus, based on an undeformed Cartan identity

On CNC Commuting Contractive Tuples

Indian Academy of Sciences (India)

The characteristic function has been an important tool for studying completely non-unitary contractions on Hilbert spaces. In this note, we consider completely non-coisometric contractive tuples of commuting operators on a Hilbert space H . We show that the characteristic function, which is now an operator-valued analytic ...

Is the environment near school associated with active commuting to school among preschoolers?

Directory of Open Access Journals (Sweden)

Jose Cazuza Farias Junior

2013-05-01

Full Text Available Available studies show that environmental factors may influence how parentes choose to commute their children from home to school. Thus, the aim of this study was to analyze the association between the characteristics of the physical and social environment near school and active commuting to school among preschool children. A school-based cross-sectional study with a sample of children aged 3to 5 years (n=914 was undertaken. Participants were selected by a single-stage cluster sampling process. To obtain data on commuting to school and demographicand socioeconomic variables, a previously validated questionnaire was used while an audit tool was used to assess the environment near school. Binarylogistic regression was used to analyze the association and results were presented as Odds Ratio values. Results showed that 28.3% (95%CI 25.5-31.3 ofthe children were active commuters from home to school. A positive association was found between public transportation (p=0.002 and social environment(p=0.004 domains and active commuting. However, this association was foundonly among children from families that did not have a car. The likelihood of achild being an active commuter was higher among those who are enrolled in schools with better environmental surroundings (OR=1.88; 95%CI 1.31-2.70. It was concluded that there was a positive association between some of the environmental factors near school and active commuting to school among children from families that did not have a car.

Cohen-Macaulay representations

CERN Document Server

Leuschke, Graham J

2012-01-01

This book is a comprehensive treatment of the representation theory of maximal Cohen-Macaulay (MCM) modules over local rings. This topic is at the intersection of commutative algebra, singularity theory, and representations of groups and algebras. Two introductory chapters treat the Krull-Remak-Schmidt Theorem on uniqueness of direct-sum decompositions and its failure for modules over local rings. Chapters 3-10 study the central problem of classifying the rings with only finitely many indecomposable MCM modules up to isomorphism, i.e., rings of finite CM type. The fundamental material--ADE/simple singularities, the double branched cover, Auslander-Reiten theory, and the Brauer-Thrall conjectures--is covered clearly and completely. Much of the content has never before appeared in book form. Examples include the representation theory of Artinian pairs and Burban-Drozd's related construction in dimension two, an introduction to the McKay correspondence from the point of view of maximal Cohen-Macaulay modules, Au...

On the generalization of linear least mean squares estimation to quantum systems with non-commutative outputs

Energy Technology Data Exchange (ETDEWEB)

Amini, Nina H. [Stanford University, Edward L. Ginzton Laboratory, Stanford, CA (United States); CNRS, Laboratoire des Signaux et Systemes (L2S) CentraleSupelec, Gif-sur-Yvette (France); Miao, Zibo; Pan, Yu; James, Matthew R. [Australian National University, ARC Centre for Quantum Computation and Communication Technology, Research School of Engineering, Canberra, ACT (Australia); Mabuchi, Hideo [Stanford University, Edward L. Ginzton Laboratory, Stanford, CA (United States)

2015-12-15

The purpose of this paper is to study the problem of generalizing the Belavkin-Kalman filter to the case where the classical measurement signal is replaced by a fully quantum non-commutative output signal. We formulate a least mean squares estimation problem that involves a non-commutative system as the filter processing the non-commutative output signal. We solve this estimation problem within the framework of non-commutative probability. Also, we find the necessary and sufficient conditions which make these non-commutative estimators physically realizable. These conditions are restrictive in practice. (orig.)

Adsorption and ring-opening of lactide on the chiral metal surface Pt(321){sup S} studied by density functional theory

Energy Technology Data Exchange (ETDEWEB)

Franke, J.-H.; Kosov, D. S. [Department of Physics, Campus Plaine - CP 231, Universite Libre de Bruxelles, 1050 Brussels (Belgium)

2015-01-28

We study the adsorption and ring-opening of lactide on the naturally chiral metal surface Pt(321){sup S}. Lactide is a precursor for polylactic acid ring-opening polymerization, and Pt is a well known catalyst surface. We study, here, the energetics of the ring-opening of lactide on a surface that has a high density of kink atoms. These sites are expected to be present on a realistic Pt surface and show enhanced catalytic activity. The use of a naturally chiral surface also enables us to study potential chiral selectivity effects of the reaction at the same time. Using density functional theory with a functional that includes the van der Waals forces in a first-principles manner, we find modest adsorption energies of around 1.4 eV for the pristine molecule and different ring-opened states. The energy barrier to be overcome in the ring-opening reaction is found to be very small at 0.32 eV and 0.30 eV for LL- and its chiral partner DD-lactide, respectively. These energies are much smaller than the activation energy for a dehydrogenation reaction of 0.78 eV. Our results thus indicate that (a) ring-opening reactions of lactide on Pt(321) can be expected already at very low temperatures, and Pt might be a very effective catalyst for this reaction; (b) the ring-opening reaction rate shows noticeable enantioselectivity.

Active commuting and sociodemographic factors among university students in Spain.

Science.gov (United States)

Molina-García, Javier; Sallis, James F; Castillo, Isabel

2014-02-01

Commuting to university represents an opportunity to incorporate physical activity (walking or biking) into students' daily routines. There are few studies that analyze patterns of transport in university populations. This cross-sectional study estimated energy expenditure from active commuting to university (ACU) and examined sociodemographic differences in findings. The sample included 518 students with a mean age of 22.4 years (59.7% female) from 2 urban universities in Valencia, Spain. Time spent in each mode of transport to university and sociodemographic factors was assessed by self-report. Nearly 35% of the students reported walking or biking as their main mode of transport. ACU (min/wk) were highest for walkers (168) and cyclists (137) and lowest for motorbike riders (0.0) and car drivers (16). Public transport users, younger students, low socioeconomic status students, and those living ≤ 2 km from the university had higher energy expenditure from active commuting than comparison groups. Biking was highest among those living 2-5 km from the university. Our findings suggest that active commuting and public transit use generated substantial weekly energy expenditure, contributed to meeting physical activity recommendations, and may aid in obesity prevention.

Commuting--a further stress factor for working people: evidence from the European Community. II. An empirical study.

Science.gov (United States)

Costa, G; Pickup, L; Di Martino, V

1988-01-01

This report summarizes the main results of research promoted by the European Foundation for the Improvement of Living and Working Conditions, concerning the impact of commuting on the health and safety of workers. An empirical study, carried out among 1167 industrial Italian workers, shows that "commuters" (workers whose journey from home to work usually does not take less than 45 min in each direction) experienced a more stressed life-style than did "non commuters" (whose journey does not take more than 20 min). Commuting appears for many workers to be a necessity which is imposed by external factors, such as the housing market and job opportunities. Commuting is shown to interfere with patterns of everyday life by restricting free-time and reducing sleeping time. A majority of commuters use public transport mainly because of cost. Public transport commuters have problems due to more changes between modes, idle waiting times and delays leading to late arrival at work. Inside transport modes, commuters suffered discomfort as a result of overcrowding, microclimatic conditions, noise and vibrations. Commuters also reported higher psychological stress scores, more health complaints, essentially of psychosomatic nature, and greater absenteeism from work due to sickness. Commuting, in addition to shiftwork, further increases sleep problems, psychosomatic complaints and difficulties with family and social life. Women commuters were at a greater disadvantage than men, having more family difficulties, more travelling complaints and higher absenteeism.

Non-commutative solitons and strong-weak duality

Energy Technology Data Exchange (ETDEWEB)

Blas, Harold [Departamento de Matematica - ICET, Universidade Federal de Mato Grosso, Av. Fernando Correa, s/n, Coxipo, 78060-900, Cuiaba - MT (Brazil)]. E-mail: blas@cpd.ufmt.br; Carrion, Hector L. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro (Brazil); Rojas, Moises [Centro Brasileiro de Pesquisas Fisicas, Rua Dr. Xavier Sigaud, 150 CEP 22290-180, Rio de Janeiro-RJ (Brazil)

2005-03-01

Some properties of the non-commutative versions of the sine-Gordon model (NCSG) and the corresponding massive Thirring theories (NCMT) are studied. Our method relies on the NC extension of integrable models and the master Lagrangian approach to deal with dual theories. The master lagrangians turn out to be the NC versions of the so-called affine Toda model coupled to matter fields (NCATM) associated to the group GL(2), in which the Toda field belongs to certain representations of either U(1)xU(1) or U(1){sub C} corresponding to the Lechtenfeld et al. (NCSG{sub 1}) or Grisaru-Penati (NCSG{sub 2}) proposals for the NC versions of the sine-Gordon model, respectively. Besides, the relevant NCMT{sub 1,2} models are written for two (four) types of Dirac fields corresponding to the Moyal product extension of one (two) copy(ies) of the ordinary massive Thirring model. The NCATM{sub 1,2} models share the same one-soliton (real Toda field sector of model 2) exact solutions, which are found without expansion in the NC parameter {theta} for the corresponding Toda and matter fields describing the strong-weak phases, respectively. The correspondence NCSG{sub 1} {r_reversible} NCMT{sub 1} is promising since it is expected to hold on the quantum level. (author)

On commuting operator exponentials, II

Indian Academy of Sciences (India)

where N is an unbounded normal operator and M is a bounded normal operator in the. Hilbert space. Keywords. Self-adjoint and normal operator; commuting normal operator exponent- ials; Borel functional calculus. 1. Introduction. Let E be a complex Hilbert space and let B(E) be the algebra of bounded linear operators.

Individual public transportation accessibility is positively associated with self-reported active commuting

DEFF Research Database (Denmark)

Djurhuus, Sune; Hansen, Henning Sten; Aadahl, Mette

2014-01-01

BACKGROUND: Active commuters have lower risk of chronic disease. Understanding which of the, to some extent, modifiable characteristics of public transportation that facilitate its use is thus important in a public health perspective. The aim of the study was to examine the association between...... individual public transportation accessibility and self-reported active commuting, and whether the associations varied with commute distance, age, and gender. METHODS: Twenty-eight thousand nine hundred twenty-eight commuters in The Capital Region of Denmark reported self-reported time spent either walking...... or cycling to work or study each day and the distance to work or study. Data were obtained from the Danish National Health Survey collected in February to April 2010. Individual accessibility by public transportation was calculated using a multi-modal network in a GIS. Multilevel logistic regression was used...

Noncommutative conformally coupled scalar field cosmology and its commutative counterpart

International Nuclear Information System (INIS)

Barbosa, G.D.

2005-01-01

We study the implications of a noncommutative geometry of the minisuperspace variables for the Friedmann-Robertson-Walker universe with a conformally coupled scalar field. The investigation is carried out by means of a comparative study of the universe evolution in four different scenarios: classical commutative, classical noncommutative, quantum commutative, and quantum noncommutative, the last two employing the Bohmian formalism of quantum trajectories. The role of noncommutativity is discussed by drawing a parallel between its realizations in two possible frameworks for physical interpretation: the NC frame, where it is manifest in the universe degrees of freedom, and in the C frame, where it is manifest through θ-dependent terms in the Hamiltonian. As a result of our comparative analysis, we find that noncommutative geometry can remove singularities in the classical context for sufficiently large values of θ. Moreover, under special conditions, the classical noncommutative model can admit bouncing solutions characteristic of the commutative quantum Friedmann-Robertson-Walker universe. In the quantum context, we find nonsingular universe solutions containing bounces or being periodic in the quantum commutative model. When noncommutativity effects are turned on in the quantum scenario, they can introduce significant modifications that change the singular behavior of the universe solutions or that render them dynamical whenever they are static in the commutative case. The effects of noncommutativity are completely specified only when one of the frames for its realization is adopted as the physical one. Nonsingular solutions in the NC frame can be mapped into singular ones in the C frame

Potential health impact of switching from car to public transportation when commuting to work.

Science.gov (United States)

Morabia, Alfredo; Mirer, Franklin E; Amstislavski, Tashia M; Eisl, Holger M; Werbe-Fuentes, Jordan; Gorczynski, John; Goranson, Chris; Wolff, Mary S; Markowitz, Steven B

2010-12-01

We assessed humidity-corrected particulate matter (PM(2.5)) exposure and physical activity (using global positioning system monitors and diaries) among 18 people who commuted by car to Queens College, New York, New York, for 5 days, and then switched to commuting for the next 5 days via public transportation. The PM(2.5) differed little between car and public transportation commutes (1.41 μg/M(3)·min; P = .226). Commuting by public transportation rather than by car increased energy expenditure (+124 kcal/day; P < .001) equivalent to the loss of 1 pound of body fat per 6 weeks.

Ring interferometry

CERN Document Server

Malykin, Grigorii B; Zhurov, Alexei

2013-01-01

This monograph is devoted to the creation of a comprehensive formalism for quantitative description of polarized modes' linear interaction in modern single-mode optic fibers. The theory of random connections between polarized modes, developed in the monograph, allows calculations of the zero shift deviations for a fiber ring interferometer. The monograph addresses also the

Commuting and happiness: What ways feel best for what kinds of people?

OpenAIRE

Lancee, S; Burger, Martijn; Veenhoven, Ruut

2018-01-01

textabstractQuestion: How happy we are, depends partly on how we live our life and part of our way of life is how we commute between home and work. In that context, we are faced with the question of how much time spent on commuting is optimal happiness wise and with what means of transportation we will feel best. Decisions about commuting are typically made as a side issue in job choice and there are indications that we are bad in predicting how such decisions will work out on our happiness i...

Seasonal and socio-demographic determinants of school commuting

DEFF Research Database (Denmark)

Bjørkelund Børrestad, Line Anita; Andersen, Lars Bo; Bere, Elling

2011-01-01

OBJECTIVE: To report prevalence of commuting to school in Norway with regard to season, gender, parental education level, ethnicity and distance to school. METHODS: Cross-sectional questionnaire data from the Fruits and Vegetables Make the Marks project collected in 2008, including 1,339 ten...... to twelve-year-old children from 27 schools. The participants were categorized according to main mode of commuting to school in the three different school seasons (fall, winter and spring) and for the full school year if more than 50% of all trips were conducted by one specific mode. RESULTS: Most pupils...

Adiabatic compression of ion rings

International Nuclear Information System (INIS)

Larrabee, D.A.; Lovelace, R.V.

1982-01-01

A study has been made of the compression of collisionless ion rings in an increasing external magnetic field, B/sub e/ = zB/sub e/(t), by numerically implementing a previously developed kinetic theory of ring compression. The theory is general in that there is no limitation on the ring geometry or the compression ratio, lambdaequivalentB/sub e/ (final)/B/sub e/ (initial)> or =1. However, the motion of a single particle in an equilibrium is assumed to be completely characterized by its energy H and canonical angular momentum P/sub theta/ with the absence of a third constant of the motion. The present computational work assumes that plasma currents are negligible, as is appropriate for a low-temperature collisional plasma. For a variety of initial ring geometries and initial distribution functions (having a single value of P/sub theta/), it is found that the parameters for ''fat'', small aspect ratio rings follow general scaling laws over a large range of compression ratios, 1 3 : The ring radius varies as lambda/sup -1/2/; the average single particle energy as lambda/sup 0.72/; the root mean square energy spread as lambda/sup 1.1/; and the total current as lambda/sup 0.79/. The field reversal parameter is found to saturate at values typically between 2 and 3. For large compression ratios the current density is found to ''hollow out''. This hollowing tends to improve the interchange stability of an embedded low β plasma. The implications of these scaling laws for fusion reactor systems are discussed

Simulation of Population-Based Commuter Exposure to NO2 Using Different Air Pollution Models

Directory of Open Access Journals (Sweden)

Martina S. Ragettli

2014-05-01

Full Text Available We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland, and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO2 as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD NO2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m−3, range: 21–61 than with a dispersion model with a lower resolution (39 ± 5 µg m−3; range: 24–51, and a land use regression model (41 ± 5 µg m−3; range: 24–54. Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas.

Discrete choice models for commuting interactions

DEFF Research Database (Denmark)

Rouwendal, Jan; Mulalic, Ismir; Levkovich, Or

An emerging quantitative spatial economics literature models commuting interactions by a gravity equation that is mathematically equivalent to a multinomial logit model. This model is widely viewed as restrictive because of the independence of irrelevant alternatives (IIA) property that links sub...

Introduction to set theory and topology

CERN Document Server

Kuratowski, Kazimierz; Stark, M

1972-01-01

Introduction to Set Theory and Topology describes the fundamental concepts of set theory and topology as well as its applicability to analysis, geometry, and other branches of mathematics, including algebra and probability theory. Concepts such as inverse limit, lattice, ideal, filter, commutative diagram, quotient-spaces, completely regular spaces, quasicomponents, and cartesian products of topological spaces are considered. This volume consists of 21 chapters organized into two sections and begins with an introduction to set theory, with emphasis on the propositional calculus and its applica

S-duality and noncommutative gauge theory

International Nuclear Information System (INIS)

Gopakumar, R.; Maldacena, J.; Minwalla, S.; Strominger, A.

2000-01-01

It is conjectured that strongly coupled, spatially noncommutative CN=4 Yang-Mills theory has a dual description as a weakly coupled open string theory in a near critical electric field, and that this dual theory is fully decoupled from closed strings. Evidence for this conjecture is given by the absence of physical closed string poles in the non-planar one-loop open string diagram. The open string theory can be viewed as living in a geometry in which space and time coordinates do not commute. (author)

Multiplicative Structure and Hecke Rings of Generator Matrices for Codes over Quotient Rings of Euclidean Domains

Directory of Open Access Journals (Sweden)

Hajime Matsui

2017-12-01

Full Text Available In this study, we consider codes over Euclidean domains modulo their ideals. In the first half of the study, we deal with arbitrary Euclidean domains. We show that the product of generator matrices of codes over the rings mod a and mod b produces generator matrices of all codes over the ring mod a b , i.e., this correspondence is onto. Moreover, we show that if a and b are coprime, then this correspondence is one-to-one, i.e., there exist unique codes over the rings mod a and mod b that produce any given code over the ring mod a b through the product of their generator matrices. In the second half of the study, we focus on the typical Euclidean domains such as the rational integer ring, one-variable polynomial rings, rings of Gaussian and Eisenstein integers, p-adic integer rings and rings of one-variable formal power series. We define the reduced generator matrices of codes over Euclidean domains modulo their ideals and show their uniqueness. Finally, we apply our theory of reduced generator matrices to the Hecke rings of matrices over these Euclidean domains.

Soft Congruence Relations over Rings

Science.gov (United States)

Xin, Xiaolong; Li, Wenting

2014-01-01

Molodtsov introduced the concept of soft sets, which can be seen as a new mathematical tool for dealing with uncertainty. In this paper, we initiate the study of soft congruence relations by using the soft set theory. The notions of soft quotient rings, generalized soft ideals and generalized soft quotient rings, are introduced, and several related properties are investigated. Also, we obtain a one-to-one correspondence between soft congruence relations and idealistic soft rings and a one-to-one correspondence between soft congruence relations and soft ideals. In particular, the first, second, and third soft isomorphism theorems are established, respectively. PMID:24949493

77 FR 45715 - Application of Key Lime Air Corporation for Commuter Authority

Science.gov (United States)

2012-08-01

... DEPARTMENT OF TRANSPORTATION Office of the Secretary [Docket DOT-OST-2009-0116] Application of Key Lime Air Corporation for Commuter Authority AGENCY: Department of Transportation. ACTION: Notice of... Lime Air Corporation fit, willing, and able, and awarding it a Commuter Air Carrier Authorization...

Getting to High School in Baltimore: Student Commuting and Public Transportation

Science.gov (United States)

Stein, Marc L.; Grigg, Jeffrey; Cronister, Curt; Chavis, Celeste; Connolly, Faith

2017-01-01

This report is the first publication of a multi-year project examining the relationship between student commutes using public transportation and on-time arrival and absenteeism. This report begins to develop a basic understanding of how students commute to high school in Baltimore with a focus on those using public transportation. The report is…

An improved 4-step commutation method application for matrix converter

DEFF Research Database (Denmark)

Guo, Yu; Guo, Yougui; Deng, Wenlang

2014-01-01

A novel four-step commutation method is proposed for matrix converter cell, 3 phase inputs to 1 phase output in this paper, which is obtained on the analysis of published commutation methods for matrix converter. The first and fourth step can be shorter than the second or third one. The discussed...... method here is implemented by programming in VHDL language. Finally, the novel method in this paper is verified by experiments....

A syntactic commutativity format for SOS

NARCIS (Netherlands)

Mousavi, M.R.; Reniers, M.A.; Groote, J.F.

2005-01-01

Considering operators defined using Structural Operational Semantics (SOS), commutativity axioms are intuitive properties that hold for many of them. Proving this intuition is usually a laborious task, requiring several pages of boring and standard proof. To save this effort, we propose a syntactic

Longitudinal associations of active commuting with wellbeing and sickness absence.

Science.gov (United States)

Mytton, Oliver Tristan; Panter, Jenna; Ogilvie, David

2016-03-01

Our aim was to explore longitudinal associations of active commuting (cycling to work and walking to work) with physical wellbeing (PCS-8), mental wellbeing (MCS-8) and sickness absence. We used data from the Commuting and Health in Cambridge study (2009 to 2012; n=801) to test associations between: a) maintenance of cycling (or walking) to work over a one year period and indices of wellbeing at the end of that one year period; and b) associations between change in cycling (or walking) to work and change in indices of wellbeing. Linear regression was used for testing associations with PCS-8 and MCS-8, and negative binomial regression for sickness absence. After adjusting for sociodemographic variables, physical activity and physical limitation, those who maintained cycle commuting reported lower sickness absence (0.46, 95% CI: 0.14-0.80; equivalent to one less day per year) and higher MCS-8 scores (1.50, 0.10-2.10) than those who did not cycle to work. The association for sickness absence persisted after adjustment for baseline sickness absence. No significant associations were observed for PCS-8. Associations between change in cycle commuting and change in indices of wellbeing were not significant. No significant associations were observed for walking. This work provides some evidence of the value of cycle commuting in improving or maintaining the health and wellbeing of adults of working age. This may be important in engaging employers in the promotion of active travel and communicating the benefits of active travel to employees. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

GreenCommute: the Nortel Networks Transportation Demand Management (TDM) Program

Energy Technology Data Exchange (ETDEWEB)

Lewinson, S [Transport Canada, Ottawa, ON (Canada)

2001-07-01

The structural elements and the environmental benefits to the employer, the employees and the community of the 'GreenCommute' program, designed by Nortel Networks and negotiated with the City of Ottawa, the National Capital Commission, and OC Transpo (the regional transportation authority), are described. The program is designed to mitigate congestion, minimize infrastructure requirements, minimize parking area requirements and to act as a pilot program for the region. The Program was designed after extensive consultation with employees. Some 87 per cent of those who responded (40 per cent response rate) expressed willingness to try a commuting alternative, including walking, cycling and car-pooling. A program is complete with a comprehensive 'GreenCoummute' website for up-to-date information, an efficient ride-matching system based on postal code, highly visible support for alternative commuting including lighted signage for all walking, cycling, transit and car-pooling information at the main entrance to the Nortel Campus, and a one-month free pass for transit riders from OC Transpo. Mid-year 2000 results indicated that the GreenCommute program was well on its way to achieve targeted objectives for 2000. Experience to-date indicate that the program is well appreciated by employees, but there is an ongoing need to market the program by varied promotion and positive messaging.

Vectors and covectors in non-commutative setting

OpenAIRE

Parfionov, G. N.; Romashev, Yu. A.; Zapatrine, R. R.

1995-01-01

Following the guidelines of classical differential geometry the `building material' for the tensor calculus in non-commutative geometry is suggested. The algebraic account of moduli of vectors and covectors is carried out.

K-theory and representation theory

International Nuclear Information System (INIS)

Kuku, A.O.

2003-01-01

This contribution includes K-theory of orders, group-rings and modules over EI categories, equivariant higher algebraic K-theory for finite, profinite and compact Lie group actions together with their relative generalisations and applications

Almost-commutative geometries beyond the standard model II: new colours

International Nuclear Information System (INIS)

Stephan, Christoph A

2007-01-01

We will present an extension of the standard model of particle physics in its almost-commutative formulation. This extension is guided by the minimal approach to almost-commutative geometries employed by Iochum et al (2004 J. Math. Phys. 45 5003 (Preprint hep-th/0312276)), Jureit and Stephan (2005 J. Math. Phys. 46 043512 (Preprint hep-th/0501134)), Schuecker (2005 Preprint hep-th/0501181), Jureit et al (2005 J. Math. Phys. 46 072303 (Preprint hep-th/0503190)) and Jureit and Stephan (2006 Preprint hep-th/0610040), although the model presented here is not minimal itself. The corresponding almost-commutative geometry leads to a Yang-Mills-Higgs model which consists of the standard model and two new fermions of opposite electromagnetic charge which may possess a new colour-like gauge group. As a new phenomenon, grand unification is no longer required by the spectral action

Non-commutative arithmetic circuits with division

Czech Academy of Sciences Publication Activity Database

Hrubeš, Pavel; Wigderson, A.

2015-01-01

Roč. 11, Article 14 (2015), s. 357-393 ISSN 1557-2862 EU Projects: European Commission(XE) 339691 - FEALORA Institutional support: RVO:67985840 Keywords : arithmetic circuits * non-commutative rational function * skew field Subject RIV: BA - General Mathematics http://theoryofcomputing.org/articles/v011a014/

Viscosity of ring polymer melts

KAUST Repository

Pasquino, Rossana

2013-10-15

We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts η0,linear to their ring counterparts η0,ring at isofrictional conditions is discussed as a function of the number of entanglements Z. In the unentangled regime η0,linear/η 0,ring is virtually constant, consistent with the earlier data, atomistic simulations, and the theoretical expectation η0,linear/ η0,ring = 2. In the entanglement regime, the Z-dependence of ring viscosity is much weaker than that of linear polymers, in qualitative agreement with predictions from scaling theory and simulations. The power-law extracted from the available experimental data in the rather limited range 1 < Z < 20, η0,linear/η0,ring ∼ Z 1.2±0.3, is weaker than the scaling prediction (η0,linear/η0,ring ∼ Z 1.6±0.3) and the simulations (η0,linear/ η0,ring ∼ Z2.0±0.3). Nevertheless, the present collection of state-of-the-art experimental data unambiguously demonstrates that rings exhibit a universal trend clearly departing from that of their linear counterparts, and hence it represents a major step toward resolving a 30-year-old problem. © 2013 American Chemical Society.

Viscosity of ring polymer melts

KAUST Repository

Pasquino, Rossana; Vasilakopoulos, Thodoris C.; Jeong, Youncheol; Lee, Hyojoon; Rogers, Simon A.; Sakellariou, Georgios; Allgaier, Jü rgen B.; Takano, Atsushi; Brá s, Ana Rita E; Chang, Taihyun; Gooß en, Sebastian; Pyckhout-Hintzen, Wim; Wischnewski, Andreas; Hadjichristidis, Nikolaos; Richter, Dieter R.; Rubinstein, Michael H.; Vlassopoulos, Dimitris

2013-01-01

We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts η0,linear to their ring counterparts η0,ring at isofrictional conditions is discussed as a function of the number of entanglements Z. In the unentangled regime η0,linear/η 0,ring is virtually constant, consistent with the earlier data, atomistic simulations, and the theoretical expectation η0,linear/ η0,ring = 2. In the entanglement regime, the Z-dependence of ring viscosity is much weaker than that of linear polymers, in qualitative agreement with predictions from scaling theory and simulations. The power-law extracted from the available experimental data in the rather limited range 1 < Z < 20, η0,linear/η0,ring ∼ Z 1.2±0.3, is weaker than the scaling prediction (η0,linear/η0,ring ∼ Z 1.6±0.3) and the simulations (η0,linear/ η0,ring ∼ Z2.0±0.3). Nevertheless, the present collection of state-of-the-art experimental data unambiguously demonstrates that rings exhibit a universal trend clearly departing from that of their linear counterparts, and hence it represents a major step toward resolving a 30-year-old problem. © 2013 American Chemical Society.

The covariant chiral ring

Energy Technology Data Exchange (ETDEWEB)

Bourget, Antoine; Troost, Jan [Laboratoire de Physique Théorique, École Normale Supérieure, 24 rue Lhomond, 75005 Paris (France)

2016-03-23

We construct a covariant generating function for the spectrum of chiral primaries of symmetric orbifold conformal field theories with N=(4,4) supersymmetry in two dimensions. For seed target spaces K3 and T{sup 4}, the generating functions capture the SO(21) and SO(5) representation theoretic content of the chiral ring respectively. Via string dualities, we relate the transformation properties of the chiral ring under these isometries of the moduli space to the Lorentz covariance of perturbative string partition functions in flat space.

Vertically coupled double quantum rings at zero magnetic field

OpenAIRE

Malet, Francesc; Barranco, Manuel; Lipparini, Enrico; Pi, Ricardo Mayol Martí; Climente, Juan Ignacio; Planelles, Josep

2006-01-01

Within local-spin-density functional theory, we have investigated the `dissociation' of few-electron circular vertical semiconductor double quantum ring artificial molecules at zero magnetic field as a function of inter-ring distance. In a first step, the molecules are constituted by two identical quantum rings. When the rings are quantum mechanically strongly coupled, the electronic states are substantially delocalized, and the addition energy spectra of the artificial molecule resemble thos...

The use of mobile applications by public transport commuters in Gauteng, South Africa

Directory of Open Access Journals (Sweden)

Cornelius J.P. Niemand

2017-06-01

Objectives: The transport industry may be regarded as early adopters of new technology. Thus, the objective of this study is to determine the perceived use and usefulness of mobile applications used within the public transport industry of South Africa. Method: This study adopted a positivist stance with a deductive research approach utilising the technology acceptance model theory as a departure point for the study. A mixed method research design was selected for this exploratory study, utilising a survey strategy comprising both closed and open-ended questions as a snapshot of the perceived usefulness of a mobile application within the South African public transport domain. A convenience sample of a hundred Gautrain commuters was selected. Main findings: Based on descriptive statistics, the main findings of this study indicate a positive relationship between the perceived ease of use and usefulness of the Gautrain Buddy application in the dissemination of Gautrain-specific information. Some of the results of the study have also been presented at an international conference [for the conference details, please refer to the reference list Niemand and Chauke (2016]. Conclusion: The sample of commuters forming part of the study indicates that mobile applications can be useful in the dissemination of public transport information in Gauteng, South Africa.

Non-commutative phase space and its space-time symmetry

International Nuclear Information System (INIS)

Li Kang; Dulat Sayipjamal

2010-01-01

First a description of 2+1 dimensional non-commutative (NC) phase space is presented, and then we find that in this formulation the generalized Bopp's shift has a symmetric representation and one can easily and straightforwardly define the star product on NC phase space. Then we define non-commutative Lorentz transformations both on NC space and NC phase space. We also discuss the Poincare symmetry. Finally we point out that our NC phase space formulation and the NC Lorentz transformations are applicable to any even dimensional NC space and NC phase space. (authors)

‘We are the future’: understanding adolescents’ intentions to commute by car or bicycle as adults

DEFF Research Database (Denmark)

Sigurdardottir, Sigrun Birna; Kaplan, Sigal; Møller, Mette

This study focuses on the intentions of adolescents to commute by car or bicycle as adults, as key elements towards promoting societal transition towards sustainable modes. The behavioral model is based on the theory of planned behavior combined with positive current travel experience, willingness...... passenger experience, general interest in cars, and car-ownership norms, and are negatively related to willingness to accept car restrictions and perceived lack of behavioral control; (ii) cycling intentions are positively related to positive cycling experience, willingness to accept car restrictions...

Eléments de mathématique algèbre commutative

CERN Document Server

Bourbaki, Nicolas

Les élements de mathématique de Nicolas Bourbaki ont pour objet une présentation rigoureuse, systématique et sans prérequis des mathématiques depuis leurs fondements. Ce premier volume du Livre d'Algèbre commutative, septième Livre du traité, est consacré aux concepts fondamentaux de l'algèbre commutative.

Influence of topology in a quantum ring

International Nuclear Information System (INIS)

Netto, A.L. Silva; Chesman, C.; Furtado, C.

2008-01-01

In this Letter we study the quantum rings in the presence of a topological defect. We use geometric theory of defects to describe one and two-dimensional quantum rings in the presence of a single screw dislocation. In addition we consider some potential in a two dimensional ring and calculate their energy spectrum. It is shown that the energy spectrum depend on the parabolic way on the burgers vectors of the screw dislocation. We also show that the presence of a topological defect introduces a new contribution for the Aharonov-Bohm effect in the quantum ring

Artificial light harvesting by dimerized Möbius ring

Science.gov (United States)

Xu, Lei; Gong, Z. R.; Tao, Ming-Jie; Ai, Qing

2018-04-01

We theoretically study artificial light harvesting by a Möbius ring. When the donors in the ring are dimerized, the energies of the donor ring are split into two subbands. Because of the nontrivial Möbius boundary condition, both the photon and acceptor are coupled to all collective-excitation modes in the donor ring. Therefore, the quantum dynamics in the light harvesting is subtly influenced by dimerization in the Möbius ring. It is discovered that energy transfer is more efficient in a dimerized ring than that in an equally spaced ring. This discovery is also confirmed by a calculation with the perturbation theory, which is equivalent to the Wigner-Weisskopf approximation. Our findings may be beneficial to the optimal design of artificial light harvesting.

Regional differences in commuting activities of inhabitants in the Tokyo metropolitan suburb

Directory of Open Access Journals (Sweden)

Masaki Kawase

2004-12-01

Full Text Available The purpose of this study is to elucidate gender differences and regional differences of co-mmuting activities by inhabitants in Japanese metropolitan suburbs. I found the different parts by districts in the metropolitan suburb. Regional factors cause gender differences in commuting activities and result in regional differences: In residential areas, inhabitants who work in metropolitan centers occupy much of the population. In older built-up areas, there are many “local” persons. In rural areas, motorization is progressing because access to rail-roads has been inconvenient. These regional factors influence the behavioral characteristics of commuting by married men, married women, never married men and never married women.

Anisotropic harmonic oscillator, non-commutative Landau problem and exotic Newton-Hooke symmetry

International Nuclear Information System (INIS)

Alvarez, Pedro D.; Gomis, Joaquim; Kamimura, Kiyoshi; Plyushchay, Mikhail S.

2008-01-01

We investigate the planar anisotropic harmonic oscillator with explicit rotational symmetry as a particle model with non-commutative coordinates. It includes the exotic Newton-Hooke particle and the non-commutative Landau problem as special, isotropic and maximally anisotropic, cases. The system is described by the same (2+1)-dimensional exotic Newton-Hooke symmetry as in the isotropic case, and develops three different phases depending on the values of the two central charges. The special cases of the exotic Newton-Hooke particle and non-commutative Landau problem are shown to be characterized by additional, so(3) or so(2,1) Lie symmetry, which reflects their peculiar spectral properties

A Study on The Marriage Phenomenolgy of Commuter Marriage Spouse

Directory of Open Access Journals (Sweden)

B’tari Sekar Nastiti

2017-08-01

Full Text Available In general, the marriage is lived by a spouse who lives together and cooperates with each other to shape the family. Recently, many couples do not live together, but in a distant city, and are called a long-distance marriage or a commuter marriage. From many reasons that create the long distance marriage, one of which is the job. The aim of this study is to find out the condition of the marriage life in commuter marriage and the dynamics on perceived marital satisfaction. This research method uses the qualitative method. Subjects in this study are 3 pairs of husband and wife practicing commuter marriage, which has a minimum marriage age of 5 years and has at least one child. The research result has shown that wives tend to experience dissatisfaction in the marriage, while the husbands feel quite happy in the marriage.

Happiness and Satisfaction with Work Commute

NARCIS (Netherlands)

Olsson, L.E.; Gärling, T.; Ettema, D.F.; Friman, M.; Fujii, S.

2012-01-01

Research suggests that for many people happiness is being able to make the routines of everyday life work, such that positive feelings dominate over negative feelings resulting from daily hassles. In line with this, a survey of work commuters in the three largest urban areas of Sweden show that

Super-Chern-Simons Theory as Superstring Theory

CERN Document Server

Grassi, P A

2004-01-01

Superstrings and topological strings with supermanifolds as target space play a central role in the recent developments in string theory. Nevertheless the rules for higher-genus computations are still unclear or guessed in analogy with bosonic and fermionic strings. Here we present a common geometrical setting to develop systematically the prescription for amplitude computations. The geometrical origin of these difficulties is the theory of integration of superforms. We provide a translation between the theory of supermanifolds and topological strings with supertarget space. We show how in this formulation one can naturally construct picture changing operators to be inserted in the correlation functions to soak up the zero modes of commuting ghost and we derive the amplitude prescriptions from the coupling with an extended topological gravity on the worldsheet. As an application we consider a simple model on R^(3|2) leading to super-Chern-Simons theory.

Potential to increase active commuting level in university area (Case study: Universitas Gadjah Mada)

Science.gov (United States)

Devi, M. K.

2017-06-01

In order to alleviate the negative impacts of motorized vehicle use as well as create sustainable environment within campus area, it is pivotal to encourage mode shifting among university students. Active transport modes such as walking, cycling, and using public transport can be considered as alternative modes. This paper tried to identify the potential to increase active commuting in UGM by understanding student’s travel behavior. ANOVA test was employed to identify the perceptions between students across residential zones toward motivators and barriers to actively commute. The findings were used to propose strategies for increasing active commuting level in UGM, which are: reducing barriers to actively commute, improving public transport services, improving walking and cycling facilities, and introducing programs to discourage motorized vehicle use.

Some Thoughts on Commutation Relations and Measurement Accuracy

International Nuclear Information System (INIS)

Noyes, H. Pierre

1999-01-01

We show that measuring the trajectories of charged particles to finite accuracy leads to the commutation relations needed for the derivation of the free space Maxwell equations using the discrete ordered calculus (DOC). We note that the finite step length derivation of the discrete difference version of the single particle Dirac equation implies the discrete version of the p, q commutation relations for a free particle. We speculate that a careful operational analysis of the change in momenta occurring in a step-wise continuous solution of the discrete Dirac equation could supply the missing source-sink terms in the DOC derivation of the Maxwell equations, and lead to a finite and discrete (''renormalized'') quantum electrodynamics (QED)

Electrically charged dilatonic black rings

International Nuclear Information System (INIS)

Kunduri, Hari K.; Lucietti, James

2005-01-01

In this Letter we present (electrically) charged dilatonic black ring solutions of the Einstein-Maxwell-dilaton theory in five dimensions and we consider their physical properties. These solutions are static and as in the neutral case possess a conical singularity. We show how one may remove the conical singularity by application of a Harrison transformation, which physically corresponds to supporting the charged ring with an electric field. Finally, we discuss the slowly rotating case for arbitrary dilaton coupling

Vibration of Elastic Functionally Graded Thick Rings

Directory of Open Access Journals (Sweden)

Guang-Hui Xu

2017-01-01

Full Text Available The free vibration behaviors of functionally graded rings were investigated theoretically. The material graded in the thickness direction according to the power law rule and the rings were assumed to be in plane stress and plane strain states. Based on the first-order shear deformation theory and the kinetic relation of von Kárman type, the frequency equation for free vibration of functionally graded ring was derived. The derived results were verified by those in literatures which reveals that the present theory can be appropriate to predict the free vibration characteristics for quite thick rings with the radius-to-thickness ratio from 60 down to 2.09. Comparison between the plane stress case and the plane strain case indicates a slight difference. Meanwhile, the effects of the structural dimensional parameters and the material inhomogeneous parameter are examined. It is interesting that the value of the logarithmic form of vibration frequency is inversely proportional to the logarithmic form of the radius-to-thickness ratio or the mean radius.

Effectiveness and implementation of interventions to increase commuter cycling to school

DEFF Research Database (Denmark)

Østergaard, Lars; Støckel, Jan Toftegaard; Andersen, Lars Bo

2015-01-01

BACKGROUND: Active transportation to school has been positively associated with various health parameters whereas only sparse evidence exists on risk of injury while commuting to school. This study investigated the overall effectiveness of cycling promotion combined with structural changes...... on cycling to school. METHODS: Interventions at public schools in three different regions in Denmark were based on planned infrastructural changes near schools (e.g. road surface and traffic regulation) and school-motivation for promoting commuter cycling. Participants were pupils from control schools (n...... = 12) or intervention schools (n = 13). All children (n = 2415) from the 4(th) and 5(th) grade were measured at baseline during spring 2010 and at follow-up one year later. RESULTS: No significant differences in commuter cycling were detected in the adjusted analyses comparing the intervention...

Towards a 'pointless' generalisation of Yang-Mills theory

International Nuclear Information System (INIS)

Chan Hongmo; Tsou Sheungtsun

1989-05-01

We examine some generalisations in physical concepts of gauge theories, leading towards a scenario corresponding to non-commutative geometry, where the concept of locality loses its usual meaning of being associated with points on a base manifold and becomes intertwined with the concept of internal symmetry, suggesting thereby a gauge theory of extended objects. Examples are given where such generalised gauge structures can be realised, in particular that of string theory. (author)

Cyclists' Behaviour: identification of factors on commuting by bicycle

Directory of Open Access Journals (Sweden)

Kátia Andrade

2013-12-01

Full Text Available In Japan, cycling is a widely accepted transportation mode and often used for commuting or other purposes. Accordingly, this paper focuses on the reasons that motivate people to cycle, even though the Japanese transportation policies towards cycling are somewhat limited when compared to other countries with high cycling levels. Behavioural and statistical analyses are presented with a focus on unimodal commuting trips. In the behavioural analysis, commuters’ views on cycling are presented. In the statistical analysis, Nested Logit models are estimated to assess factors with strong influence on cycling. This paper contributes to further understanding the behaviour of active cyclists.

Decreasing the commutation failure frequency in HVDC transmission systems

DEFF Research Database (Denmark)

Hansen (retired June, 2000), Arne; Havemann (retired June, 2000), Henrik

2000-01-01

In this paper we show how a fairly large proportion of those commutation failures that are due to single-phased short circuits to earth can be avoided. In a control circuit based on a digital signal processor (DSP) it is possible, with instantaneous results, to switch from a normal control strategy...... with equidistant firing pulses to a strategy that takes into consideration the potentially dangerous voltage changes on the supply lines, If the supply voltages are monitored continuously, it is possible to calculate the necessity of advancing the firing pulses to avoid commutation failures. In the paper...

Two applications of Berry's phase in fermionic field theory

International Nuclear Information System (INIS)

Goff, W.E.

1989-01-01

When quantized fermions are coupled to a background field, nontrivial effects may arise due to the geometry and/or topology of the space of background field configurations. In this thesis, two examples of Berry's geometrical phase in a fermionic sea are studied: the anomalous commutator in gauge field theory and the intrinsic orbital angular momentum in superfluid 3 He-A. Chapter 1 is a brief introduction. Chapter 2 reviews Berry's Phase and several toy models. Effective actions are calculated for two models in gradient expansions and the role of a geometric term is discussed. Chapter 3 investigates the anomalous commutator in the generators of gauge symmetry in field theory. Using an idea introduced by Sonoda, the Berry phase of the vacuum state is found to be the sum of the Berry phases of the individual states in the sea plus a piece due to the infinite nature of the Dirac sea. The latter is the anomalous commutator. Also found is a relative minus sign between the commutator of the total gauge symmetry generators and the commutator of the fermionic charge generators. Examples are given. In Chapter 4, a geometric way of deriving the intrinsic orbital angular momentum term in the 3 He-A equations of motion is presented. Homogeneous, adiabatically evolving textures at zero temperature are found to pick up a nonzero groundstate Berry phase, where the ground state is taken to be a filled sea of Bogoliubov quasiparticles. Interpreting the phase as a Wess-Zumino effective action for the condensate provides a geometric origin for the intrinsic angular momentum. The idea of a ground-state phase is then extended to other gap functions and a more general result is obtained. Chapter 5 concludes with a discussion of the possibility of unifying the two problems in a more general framework and directions for further work

Hawking radiation of black rings from anomalies

International Nuclear Information System (INIS)

Chen Bin; He Wei

2008-01-01

We derive Hawking radiation of five-dimensional black rings from gauge and gravitational anomalies using the method proposed by Robinson and Wilczek. We find, as in the black hole case, that the problem could reduce to a (1+1)-dimensional field theory and the anomalies result in correct Hawking temperature for neutral, dipole and charged black rings

A commutator

Energy Technology Data Exchange (ETDEWEB)

Siokhara, T.; Khibino, Y.; Tiaki, K.; Vatanabe, K.

1981-06-22

Switching of a microswitch, which switches the output electrical circuits of a unit, which supports control of industrial processes in time, is accomplished by a two arm rocking lever. The lever is driven by a cam mechanism, linked with a complex, multistage mechanical drive, which includes cylindrical gear drives and cam couplings for linkage, rotated by a synchronous electric micromotor. The unit is equipped with two subassemblies for establishment of process control: in functions of conditional time and functions of the times of day. The dials of the subassemblies for time establishment, located on the facial panel of the instrument, are equipped with arrows for the assigners with illumination and signal lamps. The lights control the mode of electric power for the instrument and the modes of the output circuits of the commutating subassembly.

The Work of Lagrange in Number Theory and Algebra

Indian Academy of Sciences (India)

GENERAL I ARTICLE. The Work of Lagrange in Number Theory and Algebra. D P Patil, C R Pranesachar and Renuka RafJindran. (left) D P Patil got his Ph.D from the School of Math- ematics, TIFR and joined. IISc in 1992. His interests are commutative algebra, algebraic geometry and algebraic number theory. (right) C R ...

K\\"{a}hler structure in the commutative limit of matrix geometry

OpenAIRE

Ishiki, Goro; Matsumoto, Takaki; Muraki, Hisayoshi

2016-01-01

We consider the commutative limit of matrix geometry described by a large-$N$ sequence of some Hermitian matrices. Under some assumptions, we show that the commutative geometry possesses a K\\"{a}hler structure. We find an explicit relation between the K\\"{a}hler structure and the matrix configurations which define the matrix geometry. We also find a relation between the matrix configurations and those obtained from the geometric quantization.

Modeling commuter preferences for the proposed bus rapid transit in Dar-es-Salaam

NARCIS (Netherlands)

Nkurunziza, A.; Zuidgeest, M.H.P.; Brussel, M.J.G.; van Maarseveen, M.F.A.M.

2012-01-01

The paper analyzes individual commuter preferences towards the proposed bus rapid transit (BRT) system in Dar-es-Salaam, Tanzania. The objective of the survey was to identify how commuters perceive and value the proposed BRT service quality attributes. A stated preference survey of potential users

On the Generalized Geometry Origin of Noncommutative Gauge Theory

CERN Document Server

Jurco, Branislav; Vysoky, Jan

2013-01-01

We discuss noncommutative gauge theory from the generalized geometry point of view. We argue that the equivalence between the commutative and semiclassically noncommutative DBI actions is naturally encoded in the generalized geometry of D-branes.

Commuting and happiness: What ways feel best for what kinds of people?

NARCIS (Netherlands)

Lancee, S; M.J. Burger (Martijn); R. Veenhoven (Ruut)

2018-01-01

textabstractQuestion: How happy we are, depends partly on how we live our life and part of our way of life is how we commute between home and work. In that context, we are faced with the question of how much time spent on commuting is optimal happiness wise and with what means of transportation we

Design, implementation, and application of 150-degree commutation VSI to improve speed range of sensored BLDC motor.

Science.gov (United States)

Ozgenel, Mehmet Cihat

2017-09-01

Permanent magnet brushless dc (BLDC) motors are very convenient for many applications such as industrial, medical, robotic, aerospace, small electric vehicles, and home applications because of their inherent satisfying dynamic characteristics. There are numerous studies about these motors and their control schemes such as sensorless control and different speed and torque control schemes. All electric motors need commutation in order to produce speed and torque. Commutation in brushed DC motors is performed by means of a brush and collector. In BLDC motors, commutation is provided electronically in contrast to the brushed dc motors. In BLDC motors, motor phase windings are energized according to the information of the rotor position by inverter transistors. Rotor position information is used for commutation. Therefore, rotor position information is required to produce speed and torque for BLDC motors. The easiest and cheapest way to obtain rotor position information is to use Hall-effect or optical sensors. BLDC motor manufacturers generally produce BLDC motors equipped with three Hall-effect position sensors. Having three position sensors on BLDC motors provides six-step commutation which ensures two phase windings are energized in each moment. The third phase is empty. In this study, all phase windings are energized in the same time. This commutation method is twelve-step or 150 degrees commutation. So that more speed can be achieved from the same BLDC motor by comparison with six-step commutation. In this paper, both six-step and twelve-step commutation methods applied to the same BLDC motor and obtained experimental results from this study were presented, examined, and discussed.

Design, implementation, and application of 150-degree commutation VSI to improve speed range of sensored BLDC motor

Science.gov (United States)

Ozgenel, Mehmet Cihat

2017-09-01

Permanent magnet brushless dc (BLDC) motors are very convenient for many applications such as industrial, medical, robotic, aerospace, small electric vehicles, and home applications because of their inherent satisfying dynamic characteristics. There are numerous studies about these motors and their control schemes such as sensorless control and different speed and torque control schemes. All electric motors need commutation in order to produce speed and torque. Commutation in brushed DC motors is performed by means of a brush and collector. In BLDC motors, commutation is provided electronically in contrast to the brushed dc motors. In BLDC motors, motor phase windings are energized according to the information of the rotor position by inverter transistors. Rotor position information is used for commutation. Therefore, rotor position information is required to produce speed and torque for BLDC motors. The easiest and cheapest way to obtain rotor position information is to use Hall-effect or optical sensors. BLDC motor manufacturers generally produce BLDC motors equipped with three Hall-effect position sensors. Having three position sensors on BLDC motors provides six-step commutation which ensures two phase windings are energized in each moment. The third phase is empty. In this study, all phase windings are energized in the same time. This commutation method is twelve-step or 150 degrees commutation. So that more speed can be achieved from the same BLDC motor by comparison with six-step commutation. In this paper, both six-step and twelve-step commutation methods applied to the same BLDC motor and obtained experimental results from this study were presented, examined, and discussed.

Travelling Solitary Wave Solutions for Generalized Time-delayed Burgers-Fisher Equation

International Nuclear Information System (INIS)

Deng Xijun; Han Libo; Li Xi

2009-01-01

In this paper, travelling wave solutions for the generalized time-delayed Burgers-Fisher equation are studied. By using the first-integral method, which is based on the ring theory of commutative algebra, we obtain a class of travelling solitary wave solutions for the generalized time-delayed Burgers-Fisher equation. A minor error in the previous article is clarified. (general)

Commuter Air Carrier Symposium (2nd) January 15-16, 1981 .

Science.gov (United States)

1981-01-16

AJAN B1 UNCLASSIFIED FAA-ASF-300-81-b NL J , E EEEIEEEI mIhIhhEIhEEEI EEIhIhEIhEEIhE IIIIIIIIIIIIIu IIIEII~lElI Second ot Denrpotmn A Fodeol~(ntiorpom...Kathryn B. Creedy AVMARK, Inc. Commuter Air 1120 19th St., N.W. 4827 Rugby Ave. Washington, D.C. 20002 Bethesda, MD 20008 J. Keith Carter Albert J...Commuter Air Piper Aircraft Corp. 4823 Rugby Rd. 3000 Medulla Rd. Bethesda, MD 20014 Lakeland, Florida 33803 -Calvin Davison ’ Crowell & Moring 1100

Gambaran Keharmonisan Commuter Family Pada Anggota Brigade Mobile Kepolisian Daerah Sumatera Utara

Directory of Open Access Journals (Sweden)

Marhisar Simatupang

2017-08-01

Full Text Available Penelitian ini bertujuan untuk mengetahui gambaran keharmonisan commuter family pada anggota BRIMOB, untuk mengetahui faktor-faktor yang menyebabkan terjadinya keharmonisan commuter family, dan untuk mengetahui strategi dan tahapan pada keluarga commuter family. Penelitian ini dilakukan pada keluarga anggota BRIMOB di Medan. Waktu penelitian dilaksanakan pada Desember 2016 sampai Maret 2017. Teknik pengambil sampel menggunakan teknik snowball sampling. Subjek penelitian berjumlah 2 keluarga anggota BRIMOB yang mengalami penikahan commuter family karena mendapatkan bawah kendali operas (BKO.  Metode penelitian yang digunakan yaitu metode penelitian kualitatif pendekatan deskriptif. Teknik pengumpulan data menggunakan wawancara, observasi dan dokumentasi. Analisis data yang digunakan adalah analisis pada tingkat awal, pada saat pengumpulan data dan setelah selesai pengumpulan data. Hasil dari penelitian ini yaitu kedua keluarga mengaku pertama kali berjauhan dengan keluarga timbul rasa kesepian dan kesedihan. Selain itu istri harus mampu menjalani dua peran sekaligus bagi anak-anaknya yaitu sebagai ayah dan ibu, saat suami melaksanakan tugas. Rasa jenuh dan takut sering dirasakan oleh kedua keluarga. Pada tahap awal mengalami commuter family, kedua keluarga mengaku mengalami ketidak percayaan pada pasangan sehingga menimbulkan masalah dalam keluarga. Masalah yang ada diselesaikan melalui dialog keluarga yang baik. Mendekatkan diri kepada Tuhan menjadi salah satu faktor mempertahankan keharmonisan keluarga. Kunci utama menjaga keharmonisan pada kedua keluarga ini, sehingga tetap bertahan adalah dengan selalu berkomunikasi, saling pengertian, kerja sama, dan membangun rasa kasih sayang. Tidak melakukan hal-hal di luar batas, dan memegang komitmen pernikahan.

Quaternionic quantum field theory

International Nuclear Information System (INIS)

Adler, S.L.

1986-01-01

In this paper the author describes a new kind of quantum mechanics or quantum field theory based on quaternions. Quaternionic quantum mechanics has a Schrodinger equation, a Dirac transformation theory, and a functional integral. Quaternionic quantum mechanics does not seem to have (except in the complex quantum mechanics specialization): A correspondence principle, and beyond this a commuting tensor product, asymptotic states, an S-matrix, a canonical formalism, coherent states or a Euclidean continuation. A new kind of quantum mechanics exists. There are many interesting formal questions to study, which should enable one to decide whether quaternionic quantum field theory is relevant for particle physics

Geodesics in hypercomplex number systems. Application to commutative quaternions

International Nuclear Information System (INIS)

Catoni, Francesco; Zampetti, Paolo; Cannata, Roberto; Bordoni, Luciana

1997-10-01

The functions of hypercomplex variable can be related to the physical fields. Following the Einstein's ideas, by which the Theory of General Relativity was developed, they want to verify if a generalisation is possible, in order to described the motion of a body in a gravitational field, by the geodesics in spaces ''deformed'' by functional transformations of hypercomplex variables. These number systems introduce new space symmetries. This paper is just a first step in the more extended study. As a first application they consider the ''commutative quaternions'' system that may be considered as a composition of complex and hyperbolic numbers. By using in this system the same functional transformations valid for the two dimensional case, elliptical geodesics are obtained, with the eccentricity related to the angle between the orbit plane and a reference plane. These geodesics do not describe the Kepler orbits, but they show a space anisotropy that might be related to planet orbits of the solar system

A matrix problem over a discrete valuation ring

International Nuclear Information System (INIS)

Zavadskii, A G; Revitskaya, U S

1999-01-01

A flat matrix problem of mixed type (over a discrete valuation ring and its skew field of fractions) is considered which naturally arises in connection with several problems in the theory of integer-valued representations and in ring theory. For this problem, a criterion for module boundedness is proved, which is stated in terms of a pair of partially ordered sets (P(A),P(B)) associated with the pair of transforming algebras (A,B) defining the problem. The corresponding statement coincides in effect with the formulation of Kleiner's well-known finite-type criterion for representations of pairs of partially ordered sets over a field. The proof is based on a reduction (which uses the techniques of differentiation) to representations of semimaximal rings (tiled orders) and partially ordered sets

Power Maps and Commutativity of Groups

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 7. Power Maps and Commutativity of Groups. Ashok Singh. Classroom Volume 9 Issue 7 July 2004 pp 70-73. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/009/07/0070-0073. Keywords. Abelian ...

Fuzzy Rough Ring and Its Prop erties

Institute of Scientific and Technical Information of China (English)

REN Bi-jun; FU Yan-ling

2013-01-01

This paper is devoted to the theories of fuzzy rough ring and its properties. The fuzzy approximation space generated by fuzzy ideals and the fuzzy rough approximation operators were proposed in the frame of fuzzy rough set model. The basic properties of fuzzy rough approximation operators were analyzed and the consistency between approximation operators and the binary operation of ring was discussed.

The role of the commutator equations in integration methods in tetrad formalisms in general relativity

International Nuclear Information System (INIS)

Edgar, S.B.

1990-01-01

The structures of the N.P. and G.H.P formalisms are reviewed in order to understand and demonstrate the important role played by the commutator equations in the associated integration procedures. Particular attention is focused on how the commutator equations are to be satisfied, or checked for consistency. It is shown that Held's integration method will only guarantee genuine solutions of Einstein's equations when all the commutator equations are correctly and completely satisfied. (authors)

Commuter exposure to inhalable, thoracic and alveolic particles in various transportation modes in Delhi.

Science.gov (United States)

Kumar, Pramod; Gupta, N C

2016-01-15

A public health concern is to understand the linkages between specific pollution sources and adverse health impacts. Commuting can be viewed as one of the significant-exposure activity in high-vehicle density areas. This paper investigates the commuter exposure to inhalable, thoracic and alveolic particles in various transportation modes in Delhi, India. Air pollution levels are significantly contributed by automobile exhaust and also in-vehicle exposure can be higher sometime than ambient levels. Motorcycle, auto rickshaw, car and bus were selected to study particles concentration along two routes in Delhi between Kashmere Gate and Dwarka. The bus and auto rickshaw were running on compressed natural gas (CNG) while the car and motorcycle were operated on gasoline fuel. Aerosol spectrometer was employed to measure inhalable, thoracic and alveolic particles during morning and evening rush hours for five weekdays. From the study, we observed that the concentration levels of these particles were greatly influenced by transportation modes. Concentrations of inhalable particles were found higher during morning in auto rickshaw (332.81 ± 90.97 μg/m(3)) while the commuter of bus exhibited higher exposure of thoracic particles (292.23 ± 110.45 μg/m(3)) and car commuters were exposed to maximum concentrations of alveolic particles (222.37 ± 26.56 μg/m(3)). We observed that in evening car commuters experienced maximum concentrations of all sizes of particles among the four commuting modes. Interestingly, motorcycle commuters were exposed to lower levels of inhalable and thoracic particles during morning and evening hours as compared to other modes of transport. The mean values were found greater than the median values for all the modes of transport suggesting that positive skewed distributions are characteristics of naturally occurring phenomenon. Copyright © 2015 Elsevier B.V. All rights reserved.

Mitigation of commutation failures in LCC–HVDC systems based on superconducting fault current limiters

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong-Geon; Khan, Umer Amir; Lee, Ho-Yun; Lim, Sung-Woo; Lee, Bang-Wook, E-mail: bangwook@hanyang.ac.kr

2016-11-15

Commutation failure in line commutated converter based HVDC systems cause severe damages on the entire power grid system. For LCC–HVDC, thyristor valves are turned on by a firing signal but turn off control is governed by the external applied AC voltage from surrounding network. When the fault occurs in AC system, turn-off control of thyristor valves is unavailable due to the voltage collapse of point of common coupling (PCC), which causes the commutation failure in LCC–HVDC link. Due to the commutation failure, the power transfer interruption, dc voltage drop and severe voltage fluctuation in the AC system could be occurred. In a severe situation, it might cause the protection system to block the valves. In this paper, as a solution to prevent the voltage collapse on PCC and to limit the fault current, the application study of resistive superconducting fault current limiter (SFCL) on LCC–HVDC grid system was performed with mathematical and simulation analyses. The simulation model was designed by Matlab/Simulink considering Haenam-Jeju HVDC power grid in Korea which includes conventional AC system and onshore wind farm and resistive SFCL model. From the result, it was observed that the application of SFCL on LCC–HVDC system is an effective solution to mitigate the commutation failure. And then the process to determine optimum quench resistance of SFCL which enables the recovery of commutation failure was deeply investigated.

Mitigation of commutation failures in LCC–HVDC systems based on superconducting fault current limiters

International Nuclear Information System (INIS)

Lee, Jong-Geon; Khan, Umer Amir; Lee, Ho-Yun; Lim, Sung-Woo; Lee, Bang-Wook

2016-01-01

Commutation failure in line commutated converter based HVDC systems cause severe damages on the entire power grid system. For LCC–HVDC, thyristor valves are turned on by a firing signal but turn off control is governed by the external applied AC voltage from surrounding network. When the fault occurs in AC system, turn-off control of thyristor valves is unavailable due to the voltage collapse of point of common coupling (PCC), which causes the commutation failure in LCC–HVDC link. Due to the commutation failure, the power transfer interruption, dc voltage drop and severe voltage fluctuation in the AC system could be occurred. In a severe situation, it might cause the protection system to block the valves. In this paper, as a solution to prevent the voltage collapse on PCC and to limit the fault current, the application study of resistive superconducting fault current limiter (SFCL) on LCC–HVDC grid system was performed with mathematical and simulation analyses. The simulation model was designed by Matlab/Simulink considering Haenam-Jeju HVDC power grid in Korea which includes conventional AC system and onshore wind farm and resistive SFCL model. From the result, it was observed that the application of SFCL on LCC–HVDC system is an effective solution to mitigate the commutation failure. And then the process to determine optimum quench resistance of SFCL which enables the recovery of commutation failure was deeply investigated.

Mitigation of commutation failures in LCC-HVDC systems based on superconducting fault current limiters

Science.gov (United States)

Lee, Jong-Geon; Khan, Umer Amir; Lee, Ho-Yun; Lim, Sung-Woo; Lee, Bang-Wook

2016-11-01

Commutation failure in line commutated converter based HVDC systems cause severe damages on the entire power grid system. For LCC-HVDC, thyristor valves are turned on by a firing signal but turn off control is governed by the external applied AC voltage from surrounding network. When the fault occurs in AC system, turn-off control of thyristor valves is unavailable due to the voltage collapse of point of common coupling (PCC), which causes the commutation failure in LCC-HVDC link. Due to the commutation failure, the power transfer interruption, dc voltage drop and severe voltage fluctuation in the AC system could be occurred. In a severe situation, it might cause the protection system to block the valves. In this paper, as a solution to prevent the voltage collapse on PCC and to limit the fault current, the application study of resistive superconducting fault current limiter (SFCL) on LCC-HVDC grid system was performed with mathematical and simulation analyses. The simulation model was designed by Matlab/Simulink considering Haenam-Jeju HVDC power grid in Korea which includes conventional AC system and onshore wind farm and resistive SFCL model. From the result, it was observed that the application of SFCL on LCC-HVDC system is an effective solution to mitigate the commutation failure. And then the process to determine optimum quench resistance of SFCL which enables the recovery of commutation failure was deeply investigated.

Essay on physics and non-commutative geometry

International Nuclear Information System (INIS)

Connes, A.

1990-01-01

Our aim, in this article, is to try to discover what physics would be like if the space in which it took place was not a set of points, but a non-commutative space. We shall not go very far in this direction, and the consequences of this investigation are for the moment either mathematical or only applied to a commutative space-time. It is clear, however, that a tool as remarkable as the Dixmier trace for analyzing logarithmic divergences should be useful to physicists. Moreover we have been able to show that a small modification of our picture of space-time gives a conceptual explanation of the Higgs fields and of the way they appear in the Weinberg-Salam model. This should allow us to make at the classical level explicit predictions of the Higgs mass: a very crude one is discussed. (author)

Associations between Recreational and Commuter Cycling, Changes in Cycling, and Type 2 Diabetes Risk

DEFF Research Database (Denmark)

Rasmussen, Martin G; Grøntved, Anders; Blond, Kim

2016-01-01

BACKGROUND: Cycling is a recreational activity and mode of commuting with substantial potential to improve public health in many countries around the world. The aim of this study was to examine prospective associations between recreational and commuter cycling, changes in cycling habits, and risk.......83 (0.69, 1.00), and 0.70 (0.57, 0.85) (p for trend = 150 min/wk to work, respectively. The main limitation of the current study is the use of self-reported physical activity. CONCLUSIONS: Commuter and recreational cycling was consistently associated with lower...

Exposure to carbon monoxide, fine particle mass, and ultrafine particle number in Jakarta, Indonesia: effect of commute mode.

Science.gov (United States)

Both, Adam F; Westerdahl, Dane; Fruin, Scott; Haryanto, Budi; Marshall, Julian D

2013-01-15

We measured real-time exposure to PM(2.5), ultrafine PM (particle number) and carbon monoxide (CO) for commuting workers school children, and traffic police, in Jakarta, Indonesia. In total, we measured exposures for 36 individuals covering 93 days. Commuters in private cars experienced mean (st dev) exposures of 22 (9.4) ppm CO, 91 (38) μg/m(3)PM(2.5), and 290 (150)×10(3) particles cm(-3). Mean concentrations were higher in public transport than in private cars for PM(2.5) (difference in means: 22%) and particle counts (54%), but not CO, likely reflecting in-vehicle particle losses in private cars owing to air-conditioning. However, average commute times were longer for private car commuters than public transport commuters (in our sample, 24% longer: 3.0 vs. 2.3 h per day). Commute and traffic-related exposures experienced by Jakarta residents are among the highest in the world, owing to high on-road concentrations and multi-hour commutes. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluating In-Car Movements in the Design of Mindful Commute Interventions: Exploratory Study.

Science.gov (United States)

Paredes, Pablo Enrique; Hamdan, Nur Al-Huda; Clark, Dav; Cai, Carrie; Ju, Wendy; Landay, James A

2017-12-04

The daily commute could be a right moment to teach drivers to use movement or breath towards improving their mental health. Long commutes, the relevance of transitioning from home to work, and vice versa and the privacy of commuting by car make the commute an ideal scenario and time to perform mindful exercises safely. Whereas driving safety is paramount, mindful exercises might help commuters decrease their daily stress while staying alert. Increasing vehicle automation may present new opportunities but also new challenges. This study aimed to explore the design space for movement-based mindful interventions for commuters. We used qualitative analysis of simulated driving experiences in combination with simple movements to obtain key design insights. We performed a semistructured viability assessment in 2 parts. First, a think-aloud technique was used to obtain information about a driving task. Drivers (N=12) were given simple instructions to complete movements (configural or breath-based) while engaged in either simple (highway) or complex (city) simulated urban driving tasks using autonomous and manual driving modes. Then, we performed a matching exercise where participants could experience vibrotactile patterns from the back of the car seat and map them to the prior movements. We report a summary of individual perceptions concerning different movements and vibrotactile patterns. Beside describing situations within a drive when it may be more likely to perform movement-based interventions, we also describe movements that may interfere with driving and those that may complement it well. Furthermore, we identify movements that could be conducive to a more relaxing commute and describe vibrotactile patterns that could guide such movements and exercises. We discuss implications for design such as the influence of driving modality on the adoption of movement, need for personal customization, the influence that social perception has on participants, and the potential

Job-induced Commuting between Two Residences – Characteristics of a Multilocational Living Arrangement in the Late Modernity

Directory of Open Access Journals (Sweden)

Darja Reuschke

2010-09-01

Full Text Available Against the background of the ongoing flexibilisation of labour markets and a rising labour force participation of (highly qualified women, job-related commuting between a main and secondary residence has become more important in Western capitalist countries as is the case in contemporary Germany. The limited number of recent empirical studies on this kind of multilocational living arrangement almost entirely focuses on commuters in couple/family households. The main objective of this article is, firstly, to provide data about the characteristics and formation contexts of job-related multilocational household organisations as a whole, in order to make a contribution to the discussion of the forms and causes of this currently important phenomenon. Secondly, by means of comparison analyses, the multilocational form of living is compared to the group of long-distance movers, in order to provide insights into who prefers commuting to migration with the complete household under which circumstances. The article draws on data of a field research study, which have been obtained from an individual based random sample from official registers of inhabitants of four metropolises in Germany. The sample was restricted to individuals with specific characteristics (in-movers, age 25 to 59. The fully structured postal interviews were complemented by qualitative telephone interviews with selected commuters. The results show that commuters are a heterogeneous group. Living in a partnership and the social connections established thereby play a prominent role for multilocational household organisations. Among male commuters, one can distinguish between those who are young, never married and predominantly childless, on the one hand, and a group of older married commuters with children in the household, on the other. The vast majority of female commuters, however, live childless. As men commute between two residences even if they live with a family, they significantly

Bikeability and methodological issues using the active commuting route environment scale (ACRES in a metropolitan setting

Directory of Open Access Journals (Sweden)

Schantz Peter

2011-01-01

Full Text Available Abstract Background Route environments can positively influence people's active commuting and thereby contribute to public health. The Active Commuting Route Environment Scale (ACRES was developed to study active commuters' perceptions of their route environments. However, bicycle commuters represent a small portion of the population in many cities and thus are difficult to study using population-based material. Therefore, the aim of this study is to expand the state of knowledge concerning the criterion-related validity of the ACRES and the representativity using an advertisement-recruited sample. Furthermore, by comparing commuting route environment profiles of inner urban and suburban areas, we provide a novel basis for understanding the relationship between environment and bikeability. Methods Bicycle commuters from Greater Stockholm, Sweden, advertisement- (n = 1379 and street-recruited (n = 93, responded to the ACRES. Traffic planning and environmental experts from the Municipality of Stockholm (n = 24 responded to a modified version of the ACRES. The criterion-related validity assessments were based on whether or not differences between the inner urban and the suburban route environments, as indicated by the experts and by four existing objective measurements, were reflected by differences in perceptions of these environments. Comparisons of ratings between advertisement- and street-recruited participants were used for the assessments of representativity. Finally, ratings of inner urban and suburban route environments were used to evaluate commuting route environment profiles. Results Differences in ratings of the inner urban and suburban route environments by the advertisement-recruited participants were in accord with the existing objective measurements and corresponded reasonably well with those of the experts. Overall, there was a reasonably good correspondence between the advertisement- and street-recruited participants' ratings

Bikeability and methodological issues using the active commuting route environment scale (ACRES) in a metropolitan setting.

Science.gov (United States)

Wahlgren, Lina; Schantz, Peter

2011-01-17

Route environments can positively influence people's active commuting and thereby contribute to public health. The Active Commuting Route Environment Scale (ACRES) was developed to study active commuters' perceptions of their route environments. However, bicycle commuters represent a small portion of the population in many cities and thus are difficult to study using population-based material. Therefore, the aim of this study is to expand the state of knowledge concerning the criterion-related validity of the ACRES and the representativity using an advertisement-recruited sample. Furthermore, by comparing commuting route environment profiles of inner urban and suburban areas, we provide a novel basis for understanding the relationship between environment and bikeability. Bicycle commuters from Greater Stockholm, Sweden, advertisement- (n = 1379) and street-recruited (n = 93), responded to the ACRES. Traffic planning and environmental experts from the Municipality of Stockholm (n = 24) responded to a modified version of the ACRES. The criterion-related validity assessments were based on whether or not differences between the inner urban and the suburban route environments, as indicated by the experts and by four existing objective measurements, were reflected by differences in perceptions of these environments. Comparisons of ratings between advertisement- and street-recruited participants were used for the assessments of representativity. Finally, ratings of inner urban and suburban route environments were used to evaluate commuting route environment profiles. Differences in ratings of the inner urban and suburban route environments by the advertisement-recruited participants were in accord with the existing objective measurements and corresponded reasonably well with those of the experts. Overall, there was a reasonably good correspondence between the advertisement- and street-recruited participants' ratings. Distinct differences in commuting route environment

The Impact of Employer Attitude to Green Commuting Plans on Reducing Car Driving: A Mixed Method Analysis

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Chuan Ding

2014-04-01

Full Text Available Reducing car trips and promoting green commuting modes are generally considered important solutions to reduce the increase of energy consumption and transportation CO2 emissions. One potential solution for alleviating transportation CO2 emissions has been to identify a role for the employer through green commuter programs. This paper offers an approach to assess the effects of employer attitudes towards green commuting plans on commuter mode choice and the intermediary role car ownership plays in the mode choice decision process. A mixed method which extends the traditional discrete choice model by incorporating latent variables and mediating variables with a structure equation model was used to better understand the commuter mode choice behaviour. The empirical data were selected from Washington-Baltimore Regional Household Travel Survey in 2007-2008, including all the trips from home to workplace during the morning hours. The model parameters were estimated using the simultaneous estimation approach and the integrated model turns out to be superior to the traditional multinomial logit (MNL model accounting for the impact of employer attitudes towards green commuting. The direct and indirect effects of socio-demographic attributes and employer attitudes towards green commuting were estimated. Through the structural equation modelling with mediating variable, this approach confirmed the intermediary nature of car ownership in the choice process. The results found in this paper provide helpful information for transportation and planning policymakers to test the transportation and planning policies effects and encourage green commuting reducing transportation CO2 emissions.

Fedosov quantization and perturbative quantum field theory

Energy Technology Data Exchange (ETDEWEB)

Collini, Giovanni

2016-12-12

Fedosov has described a geometro-algebraic method to construct in a canonical way a deformation of the Poisson algebra associated with a finite-dimensional symplectic manifold (''phase space''). His algorithm gives a non-commutative, but associative, product (a so-called ''star-product'') between smooth phase space functions parameterized by Planck's constant ℎ, which is treated as a deformation parameter. In the limit as ℎ goes to zero, the star product commutator goes to ℎ times the Poisson bracket, so in this sense his method provides a quantization of the algebra of classical observables. In this work, a generalization of Fedosov's method is developed which applies to the infinite-dimensional symplectic ''manifolds'' that occur in Lagrangian field theories. We show that the procedure remains mathematically well-defined, and we explain the relationship of the method to more standard perturbative quantization schemes in quantum field theory.

Regenerative Snubber For GTO-Commutated SCR Inverter

Science.gov (United States)

Rippel, Wally E.; Edwards, Dean B.

1992-01-01

Proposed regenerative snubbing circuit substituted for dissipative snubbing circuit in inverter based on silicon controlled rectifiers (SCR's) commutated by gate-turn-off thyristor (GTO). Intended to reduce loss of power that occurs in dissipative snubber. Principal criteria in design: low cost, simplicity, and reliability.