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Sample records for schwinger terms

  1. Schwinger terms from external field problems

    Science.gov (United States)

    Ekstrand, Christian

    1999-01-01

    The current algebra for second quantized chiral fermions in an external eld contains Schwinger terms. These are studied in two di erent ways. Both are non-perturbative and valid for arbitrary odd dimension of the physical space, although explicit expressions are only given for lower dimensions. The thesis is an introductory text to the four appended research papers. In the rst two papers, Schwinger terms are studied by realizing gauge transformations as linear operators acting on sections of the bundle of Fock spaces parametrized byvector potentials. Bosons and fermions are mixed in a Z2-graded fashion. Charged particles are considered in the rst paper and neutral particles in the second. In the the third and the fourth paper, Schwinger terms are identi ed with cocycles obtained from the family index theorem for a manifold with boundary. A generating form for the covariant anomaly and Schwinger term is obtained in the third paper. The rst three papers consider Yang-Mills while the fourth (in cooperation with Jouko Mickelsson) also includes gravitation. Key words: Schwinger terms, external anomaly, Z2-grading, index theory. eld problems, higher dimensions, chiral iii iv Preface This thesis will be about Schwinger terms. It is terms that appear in equal time commutators of currents in quantum eld theory. As a mathematical physicist I nd it hard to write a thesis about this subject. Both the physical and mathematical aspects should preferably be covered. Ihavedecided to focus on some of the mathematical tools that the Schwinger term and the closely related chiral anomaly have in common. This is part of what I have learned during the years 1994{1999 as a graduate student attheRoyal Institute of Technology. The following conventions and assumptions will be made throughout the thesis: All manifolds are assumed to be second countable and Hausdor . They are assumed to be paracompact whenever a partition of unity argument is needed. In nite-dimensional manifolds are also

  2. On Schwinger terms in (3+1)-dimensions

    International Nuclear Information System (INIS)

    Langmann, E.

    1991-02-01

    Schwinger terms arise in current algebras due to regularisations required for a consistent construction of the currents. In (1+1)-dimensions one has to normal order, and the resulting Schwinger term is the well-known Kac-Peterson cocycle. In higher dimensions, an additional wave function renormalisation is necessary leading to operator valued Schwinger terms. A rigorous, nonperturbative construction of such Schwinger terms was given by Mickelsson and Rajeev [Commun. Math. Phys. 116, 365 (1988)] in terms of determinant bundles over infinite dimensional Grassmannians. We present an alternative construction of this Schwinger term by means of quasi-free second quantization of fermions. First, we review this formalism and the construction of current algebras in (1+1)-dimensions within this framework: gauge transformations correspond to unitarily implementable Bogoliubov transformations (BTS), and the currents can be obtained from the implementers of these BTS. It is argued that in higher dimensions, gauge transformations give rise to BTS which are not unitarily implementable. We propose an implementation of such BTS by quadratic forms which allows us to obtain current algebras in (3+1)-dimensions and the Mickelsson-Rajeev Schwinger term in a simple and natural way. (author)

  3. On the operator Schwinger term in zero mass photon QED

    International Nuclear Information System (INIS)

    Bordes, G.

    1977-01-01

    The matrix element of the e.m. current commutator between the vacuum and a two-photon state is computed directly without introducing a mass for the photon. The result is zero and then seems confirm the absence of an operator Schwinger term in quantum electrodynamics

  4. The geometric phase and the Schwinger term in some models

    International Nuclear Information System (INIS)

    Grosse, H.; Langmann, E.

    1991-01-01

    We discuss quantization of fermions interacting with external fields and observe the occurrence of equivalent as well as inequivalent representations of the canonical anticommutation relations. Implementability of gauge and axial gauge transformations leads to generators which fulfill an algebra of charges with Schwinger term. This term can be written as a cocycle and leads to the boson-fermion correspondence. Transport of a quantum mechanical system along a closed loop of parameter space may yield a geometric mechanical system along a closed loop of parameter space may yield a geometric phase. We discuss models for which nonintegrable phase factors are obtained from the adiabatic parallel transport. After second quantization one obtains, in addition, a Schwinger term. Depending on the type of transformation a subtle relationship between these two obstructions can occur. We indicate finally how we may transport density matrices along closed loops in parameter space. (authors)

  5. The Schwinger term and the Berry phase in simple models

    International Nuclear Information System (INIS)

    Grosse, H.

    1989-01-01

    We discuss quantization of fermions interacting with external fields and observe the occurrence of equivalent as well as inequivalent representations of the canonical anticommutation relations. Implementability of gauge and axial gauge transformations leads to generators which fulfill an algebra of charges with Schwinger term. This term can be written as a cocycle and leads to the boson-fermion correspondence. During an adiabatic transport along closed loops in a parameter space we may pick up a nonintegrable phase factor, usually called the Berry phase. We study the occurrence of such a topological phase in a model and give the parallel transport for density matrices. After second quantization one may pick up both a Berry phase and a Schwinger term. 13 refs. (Author)

  6. On current superalgebras and super-schwinger terms

    International Nuclear Information System (INIS)

    Grosse, H.; Langmann, E.

    1990-01-01

    We present a general construction of current superalgebras within the framework of quasi-free second quantization of bosons and fermions. Mathematically speaking, we give projective representations of certain Lie superalgebras realized as bounded operators on Z 2 -graded Hilbert spaces and, more generally, on Grassmann algebra-modules. The super-Schwinger terms occuring correspond to Z 2 -graded two-cocycles. (Authors) 11 refs

  7. Determination of covariant Schwinger terms in anomalous gauge theories

    International Nuclear Information System (INIS)

    Kelnhofer, G.

    1991-01-01

    A functional integral method is used to determine equal time commutators between the covariant currents and the covariant Gauss-law operators in theories which are affected by an anomaly. By using a differential geometrical setup we show how the derivation of consistent- and covariant Schwinger terms can be understood on an equal footing. We find a modified consistency condition for the covariant anomaly. As a by-product the Bardeen-Zumino functional, which relates consistent and covariant anomalies, can be interpreted as connection on a certain line bundle over all gauge potentials. Finally the commutator anomalies are calculated for the two- and four dimensional case. (Author) 13 refs

  8. Determination of covariant Schwinger terms in anomalous gauge theories

    International Nuclear Information System (INIS)

    Kelnhofer, G.

    1991-01-01

    A functional integral method is used to determine equal time commutators between the covariant currents and the covariant Gauss-law operators in theories which are affected by an anomaly. By using a differential geometrical setup we show how the derivation of consistent- and covariant Schwinger terms can be understood on an equal footing. We find a modified consistency condition for the covariant anomaly. As a by-product the Bardeen-Zumino functional, which relates consistent and covariant anomalies, can be interpreted as connection on a certain line bundle over all gauge potentials. Finally the covariant commutator anomalies are calculated for the two- and four dimensional case. (orig.)

  9. 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

  10. Overview on the anomaly and Schwinger term in two dimensional QED

    International Nuclear Information System (INIS)

    Adam, C.; Bertlmann, R.A.; Hofer, P.

    1993-01-01

    The axial anomaly of two-dimensional QED is computed in different ways (perturbative, via dispersion integrals, path integral and index theorem) and their relation is discussed as well as the relation between anomaly, Schwinger term and the Dirac vacuum. Some features of the special case of massless fermions (Schwinger model) and some methods of exactly solving it are demonstrated. (authors)

  11. Schwinger terms of the super-Virasoro algebra in (1,0) superspace

    International Nuclear Information System (INIS)

    Lee, J.; Louis, J.; Ovrut, B.A.

    1988-01-01

    We calculate the Schwinger terms of the super-Virasoro algebra for the heterotic string, and the associated anomalous seagull terms, directly from the Lorentz and super-Weyl anomalies using the (1,0) superspace formalism. The various supercurrents in (1,0) superspace are also discussed

  12. Nature of the Schwinger term in spinor electrodynamics. [Dispersion formulation,dimensions,green functions,c-number,linear unitarity condition

    Energy Technology Data Exchange (ETDEWEB)

    Nishijima, K; Sasaki, R [Tokyo Univ. (Japan). Dept. of Physics

    1975-06-01

    On the basis of the dispersion formulation of field theories the Schwinger term in spinor electrodynamics is shown to be a c-number. The essence of the proof consists in the dimensional argument and the characteristic features of the linear unitarity condition for a set of Green's functions involving the Schwinger term.

  13. On the algebraic structure of covariant anomalies and covariant Schwinger terms

    International Nuclear Information System (INIS)

    Kelnhofer, G.

    1992-01-01

    A cohomological characterization of covariant anomalies and covariant Schwinger terms in an anomalous Yang-Mills theory is formulated and w ill be geometrically interpreted. The BRS and anti-BRS transformations are defined as purely differential geometric objects. Finally the covariant descent equations are formulated within this context. (author)

  14. Investigation of anomalous Schwinger terms based on the Batalin-Fradkin-Vilkovisky formalism

    International Nuclear Information System (INIS)

    Fujiwara, T.; Igarashi, Y.; Kubo, J.

    1991-01-01

    On the basis of the generalized hamiltonian formalism of Batalin, Fradkin and Vilkovisky, we investigate the algebraic structure of the anomalous Schwinger terms that appear in the nilpotency condition and/or the time development of the BRST charge in Yang-Mills theory. These anomalies are shown to satisfy a set of consistency conditions which originate from the (super-)Jacobi identities among (anti-)commutation relations. The consistency conditions are solved in an exhaustive fashion to order h- 2 and our results are independent of a wide class of regularization schemes and gauge choices. (orig.)

  15. Fermion current algebras and Schwinger terms in (3+1)-dimensions

    International Nuclear Information System (INIS)

    Langmann, E.

    1994-01-01

    We discuss the restricted linear group in infinite dimensions modeled by the Schatten class of rank 2p=4 which contains the (3+1)-dimensional analogs of the loop groups and is closely related to Yang-Mills theory with fermions in (3+1)-dimensions. We give an alternative to the construction of the ''highest weight'' representation of this group found by Mickelsson and Rajeev. Our approach is close to quantum field theory, with the elements of this group regarded as Bogoliubov transformations for fermions in an external Yang-Mills field. Though these cannot be unitarily implemented in the physically relevant representation of the fermion field algebra, we argue that they can be implemented by sesquilinear forms, and that there is a (regularized) product of forms providing an appropriate group structure. On the Lie algebra level, this gives an explicit, non-perturbative construction of fermion current algebras in (3+1) space-time dimensions which explicitly shows that the ''wave function renormalization'' required for a consistent definition of the currents and their Lie bracket naturally leads to the Schwinger term identical with the Mickelsson-Rajeev cocycle. Though the explicit form of the Schwinger term is given only for the case p=2, our arguments apply also to the restricted linear groups modeled by Schatten classes of rank 2p=6, 8, .. corresponding to current algebras in (d+1)-dimensions, d=5, 7, .. (orig.)

  16. Dual simulation of the massless lattice Schwinger model with topological term and non-zero chemical potential

    Science.gov (United States)

    Göschl, Daniel

    2018-03-01

    We discuss simulation strategies for the massless lattice Schwinger model with a topological term and finite chemical potential. The simulation is done in a dual representation where the complex action problem is solved and the partition function is a sum over fermion loops, fermion dimers and plaquette-occupation numbers. We explore strategies to update the fermion loops coupled to the gauge degrees of freedom and check our results with conventional simulations (without topological term and at zero chemical potential), as well as with exact summation on small volumes. Some physical implications of the results are discussed.

  17. Chiral Schwinger model with the Faddeevian regularization in the light-front frame: construction of the gauge-invariant theory through the Stueckelberg term, Hamiltonian and BRST formulations

    International Nuclear Information System (INIS)

    Kulshreshtha, U.

    1998-01-01

    A chiral Schwinger model with the Faddeevian regularization a la Mitra is studied in the light-front frame. The front-form theory is found to be gauge-non-invariant. The Hamiltonian formulation of this gauge-non-invariant theory is first investigated and then the Stueckelberg term for this theory is constructed. Finally, the Hamiltonian and BRST formulations of the resulting gauge-invariant theory, obtained by the inclusion of the Stueckelberg term in the action of the above gauge-non-invariant theory, are investigated with some specific gauge choices. (orig.)

  18. Dynamically Assisted Schwinger Mechanism

    International Nuclear Information System (INIS)

    Schuetzhold, Ralf; Gies, Holger; Dunne, Gerald

    2008-01-01

    We study electron-positron pair creation from the Dirac vacuum induced by a strong and slowly varying electric field (Schwinger effect) which is superimposed by a weak and rapidly changing electromagnetic field (dynamical pair creation). In the subcritical regime where both mechanisms separately are strongly suppressed, their combined impact yields a pair creation rate which is dramatically enhanced. Intuitively speaking, the strong electric field lowers the threshold for dynamical particle creation--or, alternatively, the fast electromagnetic field generates additional seeds for the Schwinger mechanism. These findings could be relevant for planned ultrahigh intensity lasers

  19. Chiral Schwinger model and lattice fermionic regularizations

    International Nuclear Information System (INIS)

    Kieu, T.D.; Sen, D.; Xue, S.

    1988-01-01

    The chiral Schwinger model is studied on the lattice with use of Wilson fermions. The arbitrary mass term for the gauge boson is shown to originate from the arbitrariness of the Wilson parameter, which is required to avoid the doubling phenomenon on the lattice. The necessity for such a term is thus demonstrated in contrast to the mere admissibility as indicated by previous continuum calculations

  20. Massive Schwinger model at finite θ

    Science.gov (United States)

    Azcoiti, Vicente; Follana, Eduardo; Royo-Amondarain, Eduardo; Di Carlo, Giuseppe; Vaquero Avilés-Casco, Alejandro

    2018-01-01

    Using the approach developed by V. Azcoiti et al. [Phys. Lett. B 563, 117 (2003), 10.1016/S0370-2693(03)00601-4], we are able to reconstruct the behavior of the massive one-flavor Schwinger model with a θ term and a quantized topological charge. We calculate the full dependence of the order parameter with θ . Our results at θ =π are compatible with Coleman's conjecture on the phase diagram of this model.

  1. Lorentz Invariant Spectrum of Minimal Chiral Schwinger Model

    Science.gov (United States)

    Kim, Yong-Wan; Kim, Seung-Kook; Kim, Won-Tae; Park, Young-Jai; Kim, Kee Yong; Kim, Yongduk

    We study the Lorentz transformation of the minimal chiral Schwinger model in terms of the alternative action. We automatically obtain a chiral constraint, which is equivalent to the frame constraint introduced by McCabe, in order to solve the frame problem in phase space. As a result we obtain the Lorentz invariant spectrum in any moving frame by choosing a frame parameter.

  2. Are Crab nanoshots Schwinger sparks?

    Energy Technology Data Exchange (ETDEWEB)

    Stebbins, Albert [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Yoo, Hojin [Univ. of Wisconsin, Madison, WI (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)

    2015-05-21

    The highest brightness temperature ever observed are from "nanoshots" from the Crab pulsar which we argue could be the signature of bursts of vacuum e± pair production. If so this would be the first time the astronomical Schwinger effect has been observed. These "Schwinger sparks" would be an intermittent but extremely powerful, ~103 L, 10 PeV e± accelerator in the heart of the Crab. These nanosecond duration sparks are generated in a volume less than 1 m3 and the existence of such sparks has implications for the small scale structure of the magnetic field of young pulsars such as the Crab. As a result, this mechanism may also play a role in producing other enigmatic bright short radio transients such as fast radio bursts.

  3. Pinch technique for Schwinger-Dyson equations

    International Nuclear Information System (INIS)

    Binosi, Daniele; Papavassiliou, Joannis

    2007-01-01

    In the context of scalar QED we derive the pinch technique self-energies and vertices directly from the Schwinger-Dyson equations. After reviewing the perturbative construction, we discuss in detail the general methodology and the basic field-theoretic ingredients necessary for the completion of this task. The construction requires the simultaneous treatment of the equations governing the scalar self-energy and the fundamental interaction vertices. The resulting non-trivial rearrangement of terms generates dynamically the Schwinger-Dyson equations for the corresponding Green's functions of the background field method. The proof relies on the extensive use of the all-order Ward-identities satisfied by the full vertices of the theory and by the one-particle-irreducible kernels appearing in the usual skeleton expansion. The Ward identities for these latter quantities are derived formally, and several subtleties related to the structure of the multiparticle kernels are addressed. The general strategy for the generalization of the method in a non-Abelian context is briefly outlined, and some of the technical difficulties are discussed

  4. Schwinger Model Mass Anomalous Dimension

    CERN Document Server

    Keegan, Liam

    2016-06-20

    The mass anomalous dimension for several gauge theories with an infrared fixed point has recently been determined using the mode number of the Dirac operator. In order to better understand the sources of systematic error in this method, we apply it to a simpler model, the massive Schwinger model with two flavours of fermions, where analytical results are available for comparison with the lattice data.

  5. Supersymmetry and the chiral Schwinger model

    International Nuclear Information System (INIS)

    Amorim, R.; Das, A.

    1998-01-01

    We have constructed the N= (1) /(2) supersymmetric general Abelian model with asymmetric chiral couplings. This leads to a N= (1) /(2) supersymmetrization of the Schwinger model. We show that the supersymmetric general model is plagued with problems of infrared divergence. Only the supersymmetric chiral Schwinger model is free from such problems and is dynamically equivalent to the chiral Schwinger model because of the peculiar structure of the N= (1) /(2) multiplets. copyright 1998 The American Physical Society

  6. Julian Schwinger — Personal Recollections

    Science.gov (United States)

    Martin, Paul C.

    We're gathered here today to salute Julian Schwinger, a towering figure of the golden age of physics — and a kind and gentle human being. Even at our best universities, people with Julian's talent and his passion for discovery and perfection are rare — so rare that neither they nor the rest of us know how to take best advantage of their genius. The failure to find a happier solution to this dilemma in recent years has concerned many of us. It should not becloud the fact that over their lifetimes, few physicists, if any, have surmounted this impedance mismatch more effectively than Julian, conveying not only knowledge but lofty values and aspirations directly and indirectly to thousands of physicists…

  7. New solution for the Schwinger model

    International Nuclear Information System (INIS)

    Baaquie, B.E.

    1980-08-01

    We solve the Schwinger model exactly using the path integral. The fermion sector is solved using the axial current anomaly. We then study the Wilson loop integral for the interacting theory, and discuss the Wilson criterion for confinement. (author)

  8. SU(N) Irreducible Schwinger Bosons

    OpenAIRE

    Mathur, Manu; Raychowdhury, Indrakshi; Anishetty, Ramesh

    2010-01-01

    We construct SU(N) irreducible Schwinger bosons satisfying certain U(N-1) constraints which implement the symmetries of SU(N) Young tableaues. As a result all SU(N) irreducible representations are simple monomials of $(N-1)$ types of SU(N) irreducible Schwinger bosons. Further, we show that these representations are free of multiplicity problems. Thus all SU(N) representations are made as simple as SU(2).

  9. Calculation of the fermionic determinant in the Schwinger model

    International Nuclear Information System (INIS)

    Dias, S.A.; Linhares, C.A.

    1991-01-01

    We compute explicitly the fermionic determinant and the effective action for the generalized Schwinger model in two dimensions and compare it with respective results for the particular cases of the Schwinger, chiral Schwinger and axial Schwinger models. The parameters that signal the ambiguity in the regularization scheme fo the determinant are introduced through the point-splitting method. The Wess-Zumino functional is also obtained and compared with the known expressions for the above-mentioned particular cases. (author)

  10. Schwinger-Keldysh superspace in quantum mechanics

    Science.gov (United States)

    Geracie, Michael; Haehl, Felix M.; Loganayagam, R.; Narayan, Prithvi; Ramirez, David M.; Rangamani, Mukund

    2018-05-01

    We examine, in a quantum mechanical setting, the Hilbert space representation of the Becchi, Rouet, Stora, and Tyutin (BRST) symmetry associated with Schwinger-Keldysh path integrals. This structure had been postulated to encode important constraints on influence functionals in coarse-grained systems with dissipation, or in open quantum systems. Operationally, this entails uplifting the standard Schwinger-Keldysh two-copy formalism into superspace by appending BRST ghost degrees of freedom. These statements were previously argued at the level of the correlation functions. We provide herein a complementary perspective by working out the Hilbert space structure explicitly. Our analysis clarifies two crucial issues not evident in earlier works: first, certain background ghost insertions necessary to reproduce the correct Schwinger-Keldysh correlators arise naturally, and, second, the Schwinger-Keldysh difference operators are systematically dressed by the ghost bilinears, which turn out to be necessary to give rise to a consistent operator algebra. We also elaborate on the structure of the final state (which is BRST closed) and the future boundary condition of the ghost fields.

  11. Schwinger mechanism in linear covariant gauges

    Science.gov (United States)

    Aguilar, A. C.; Binosi, D.; Papavassiliou, J.

    2017-02-01

    In this work we explore the applicability of a special gluon mass generating mechanism in the context of the linear covariant gauges. In particular, the implementation of the Schwinger mechanism in pure Yang-Mills theories hinges crucially on the inclusion of massless bound-state excitations in the fundamental nonperturbative vertices of the theory. The dynamical formation of such excitations is controlled by a homogeneous linear Bethe-Salpeter equation, whose nontrivial solutions have been studied only in the Landau gauge. Here, the form of this integral equation is derived for general values of the gauge-fixing parameter, under a number of simplifying assumptions that reduce the degree of technical complexity. The kernel of this equation consists of fully dressed gluon propagators, for which recent lattice data are used as input, and of three-gluon vertices dressed by a single form factor, which is modeled by means of certain physically motivated Ansätze. The gauge-dependent terms contributing to this kernel impose considerable restrictions on the infrared behavior of the vertex form factor; specifically, only infrared finite Ansätze are compatible with the existence of nontrivial solutions. When such Ansätze are employed, the numerical study of the integral equation reveals a continuity in the type of solutions as one varies the gauge-fixing parameter, indicating a smooth departure from the Landau gauge. Instead, the logarithmically divergent form factor displaying the characteristic "zero crossing," while perfectly consistent in the Landau gauge, has to undergo a dramatic qualitative transformation away from it, in order to yield acceptable solutions. The possible implications of these results are briefly discussed.

  12. Perturbative versus Schwinger-propagator method for the calculation of amplitudes in a magnetic field

    International Nuclear Information System (INIS)

    Nieves, Jose F.; Pal, Palash B.

    2006-01-01

    We consider the calculation of amplitudes for processes that take place in a constant background magnetic field, first using the standard method for the calculation of an amplitude in an external field, and second utilizing the Schwinger propagator for charged particles in a magnetic field. We show that there are processes for which the Schwinger-propagator method does not yield the total amplitude. We explain why the two methods yield equivalent results in some cases and indicate when we can expect the equivalence to hold. We show these results in fairly general terms and illustrate them with specific examples as well

  13. The inverse problem for Schwinger pair production

    Directory of Open Access Journals (Sweden)

    F. Hebenstreit

    2016-02-01

    Full Text Available The production of electron–positron pairs in time-dependent electric fields (Schwinger mechanism depends non-linearly on the applied field profile. Accordingly, the resulting momentum spectrum is extremely sensitive to small variations of the field parameters. Owing to this non-linear dependence it is so far unpredictable how to choose a field configuration such that a predetermined momentum distribution is generated. We show that quantum kinetic theory along with optimal control theory can be used to approximately solve this inverse problem for Schwinger pair production. We exemplify this by studying the superposition of a small number of harmonic components resulting in predetermined signatures in the asymptotic momentum spectrum. In the long run, our results could facilitate the observation of this yet unobserved pair production mechanism in quantum electrodynamics by providing suggestions for tailored field configurations.

  14. Time-ordered products and Schwinger functions

    International Nuclear Information System (INIS)

    Eckmann, J.P.; Epstein, H.

    1979-01-01

    It is shown that every system of time-ordered products for a local field theory determines a related system of Schwinger functions possessing an extended form of Osterwalder-Schrader positivity and that the converse is true provided certain growth conditions are satisfied. This is applied to the phi 3 4 theory and it is shown that the time-ordered functions and S-matrix elements admit the standard perturbation series as asymptotic expansions. (orig.) [de

  15. Gravity Before Einstein and Schwinger Before Gravity

    Science.gov (United States)

    Trimble, Virginia L.

    2012-05-01

    Julian Schwinger was a child prodigy, and Albert Einstein distinctly not; Schwinger had something like 73 graduate students, and Einstein very few. But both thought gravity was important. They were not, of course, the first, nor is the disagreement on how one should think about gravity that is being highlighted here the first such dispute. The talk will explore, first, several of the earlier dichotomies: was gravity capable of action at a distance (Newton), or was a transmitting ether required (many others). Did it act on everything or only on solids (an odd idea of the Herschels that fed into their ideas of solar structure and sunspots)? Did gravitational information require time for its transmission? Is the exponent of r precisely 2, or 2 plus a smidgeon (a suggestion by Simon Newcomb among others)? And so forth. Second, I will try to say something about Scwinger's lesser known early work and how it might have prefigured his "source theory," beginning with "On the Interaction of Several Electrons (the unpublished, 1934 "zeroth paper," whose title somewhat reminds one of "On the Dynamics of an Asteroid," through his days at Berkeley with Oppenheimer, Gerjuoy, and others, to his application of ideas from nuclear physics to radar and of radar engineering techniques to problems in nuclear physics. And folks who think good jobs are difficult to come by now might want to contemplate the couple of years Schwinger spent teaching elementary physics at Purdue before moving on to the MIT Rad Lab for war work.

  16. The Schwinger Model on the torus

    International Nuclear Information System (INIS)

    Azakov, S.

    1996-08-01

    The classical and quantum aspects of the Schwinger model on the torus are considered. First we find explicitly all zero modes of the Dirac operator in the topological sectors with nontrivial Chern index and its spectrum. In the second part we determine the regularized effective action and discuss the propagators related to it. Finally we calculate the gauge invariant averages of the fermion bilinears and correlation functions of currents and densities. We show that in the infinite volume limit the well-known result for the chiral condensate can be obtained and the clustering property can be established. (author). 23 refs

  17. Aliasing modes in the lattice Schwinger model

    International Nuclear Information System (INIS)

    Campos, Rafael G.; Tututi, Eduardo S.

    2007-01-01

    We study the Schwinger model on a lattice consisting of zeros of the Hermite polynomials that incorporates a lattice derivative and a discrete Fourier transform with many properties. Such a lattice produces a Klein-Gordon equation for the boson field and the exact value of the mass in the asymptotic limit if the boundaries are not taken into account. On the contrary, if the lattice is considered with boundaries new modes appear due to aliasing effects. In the continuum limit, however, this lattice yields also a Klein-Gordon equation with a reduced mass

  18. Equivalence of Dirac quantization and Schwinger's action principle quantization

    International Nuclear Information System (INIS)

    Das, A.; Scherer, W.

    1987-01-01

    We show that the method of Dirac quantization is equivalent to Schwinger's action principle quantization. The relation between the Lagrange undetermined multipliers in Schwinger's method and Dirac's constraint bracket matrix is established and it is explicitly shown that the two methods yield identical (anti)commutators. This is demonstrated in the non-trivial example of supersymmetric quantum mechanics in superspace. (orig.)

  19. Schwinger variational calculation of ionization of hydrogen atoms for ...

    Indian Academy of Sciences (India)

    Schwinger variational calculation of ionization of hydrogen atoms for large momentum transfers. K CHAKRABARTI. Department of Mathematics, Scottish Church College, 1 & 3 Urquhart Square,. Kolkata 700 006, India. MS received 7 July 2001; revised 10 October 2001. Abstract. Schwinger variational principle is used here ...

  20. A Csup(*)-algebra approach to the Schwinger model

    International Nuclear Information System (INIS)

    Carey, A.L.; Hurst, C.A.

    1981-01-01

    If cutoffs are introduced then existing results in the literature show that the Schwinger model is dynamically equivalent to a boson model with quadratic Hamiltonian. However, the process of quantising the Schwinger model destroys local gauge invariance. Gauge invariance is restored by the addition of a counterterm, which may be seen as a finite renormalisation, whereupon the Schwinger model becomes dynamically equivalent to a linear boson gauge theory. This linear model is exactly soluble. We find that different treatments of the supplementary (i.e. Lorentz) condition lead to boson models with rather different properties. We choose one model and construct, from the gauge invariant subalgebra, a class of inequivalent charge sectors. We construct sectors which coincide with those found by Lowenstein and Swieca for the Schwinger model. A reconstruction of the Hilbert space on which the Schwinger model exists is described and fermion operators on this space are defined. (orig.)

  1. Schwinger-Dyson operator of Yang-Mills matrix models with ghosts and derivations of the graded shuffle algebra

    NARCIS (Netherlands)

    Krishnaswami, G.S.

    2008-01-01

    We consider large-N multi-matrix models whose action closely mimics that of Yang-Mills theory, including gauge-fixing and ghost terms. We show that the factorized Schwinger-Dyson loop equations, expressed in terms of the generating series of gluon and ghost correlations G( ), are quadratic equations

  2. Dyson-Schwinger equations in quantum electrodynamics

    International Nuclear Information System (INIS)

    Slim, H.A.

    1981-01-01

    A quantum field theory is completely determined by the knowledge of its Green functions and this thesis is concerned with the Salam and Delbourgo approximation method for the determination of the Green functions. In chapter 2 a Lorentz covariant, canonical formulation for quantum electrodynamics is described. In chapter 3 the definition of the Green functions in quantum electrodynamics is given with a derivation of the Dyson-Schwinger equations. The Ward-Takahashi identities, which are a consequence of current conservation, are derived and finally renormalization is briefly mentioned and the equations for the renormalized quantities are given. The gauge transformations, changing the gauge-parameter, a, discussed in Chapter 2 for the field operators, also have implications for the Green functions, and these are worked out in Chapter 4 for the electron propagator, which is not gauge-invariant. Before developing the main approximation, a simple, non-relativistic model is studied in Chapter 5. It has the feature of being exactly solvable in a way which closely resembles the approximation method of Chapter 6 for relativistic quantum electrodynamics. There the Dyson-Schwinger equations for the electron and photon propagator are studied. In chapter 7, the Johnson-Baker-Willey program of finite quantum electrodynamics is considered, in connection with the Ansatz of Salam and Delbourgo, and the question of a possible fixed point of the coupling constant is considered. In the last chapter, some remarks are made about how the results of the approximation scheme can be improved. (Auth.)

  3. DeWitt-Schwinger renormalization and vacuum polarization in d dimensions

    International Nuclear Information System (INIS)

    Thompson, R. T.; Lemos, Jose P. S.

    2009-01-01

    Calculation of the vacuum polarization, 2 (x)>, and expectation value of the stress tensor, μν (x)>, has seen a recent resurgence, notably for black hole spacetimes. To date, most calculations of this type have been done only in four dimensions. Extending these calculations to d dimensions includes d-dimensional renormalization. Typically, the renormalizing terms are found from Christensen's covariant point splitting method for the DeWitt-Schwinger expansion. However, some manipulation is required to put the correct terms into a form that is compatible with problems of the vacuum polarization type. Here, after a review of the current state of affairs for 2 (x)> and μν (x)> calculations and a thorough introduction to the method of calculating 2 (x)>, a compact expression for the DeWitt-Schwinger renormalization terms suitable for use in even-dimensional spacetimes is derived. This formula should be useful for calculations of 2 (x)> and μν (x)> in even dimensions, and the renormalization terms are shown explicitly for four and six dimensions. Furthermore, use of the finite terms of the DeWitt-Schwinger expansion as an approximation to 2 (x)> for certain spacetimes is discussed, with application to four and five dimensions.

  4. Hamiltonian formulation of QCD in the Schwinger gauge

    International Nuclear Information System (INIS)

    Schutte, D.

    1989-01-01

    The structure of the Hamiltonian related to a regularized non-Abelian gauge field theory is discussed in the light of different choices for gauge-invariant wave functionals (loop space, Coulomb, axial, Schwinger gauge). Arguments are given for the suggestion that the Schwinger gauge offers a specially suited framework for the computation of bound-state (hadron) properties. The most important reasons are the manifest rotation invariance, the lack of a Gribov horizon (giving standard many-body techniques a better chance), and the fact that a regularization analogous to the lattice regularization is easily implementable. Some details of the Schwinger-gauge Hamiltonian theory are discussed

  5. Schwinger-Keldysh diagrammatics for primordial perturbations

    Science.gov (United States)

    Chen, Xingang; Wang, Yi; Xianyu, Zhong-Zhi

    2017-12-01

    We present a systematic introduction to the diagrammatic method for practical calculations in inflationary cosmology, based on Schwinger-Keldysh path integral formalism. We show in particular that the diagrammatic rules can be derived directly from a classical Lagrangian even in the presence of derivative couplings. Furthermore, we use a quasi-single-field inflation model as an example to show how this formalism, combined with the trick of mixed propagator, can significantly simplify the calculation of some in-in correlation functions. The resulting bispectrum includes the lighter scalar case (mcase (m>3H/2) that has not been explicitly computed for this model. The latter provides a concrete example of quantum primordial standard clocks, in which the clock signals can be observably large.

  6. Schwinger variational principle applied to molecular photoionization

    International Nuclear Information System (INIS)

    Smith, M.E.

    1985-01-01

    A method based upon the Schwinger variational principle was developed to study molecular photoionization and electron-molecule scattering. Exact static-exchange solutions to the equations for the continuum orbitals are obtained within the Hartree-Fock approximation; and from these cross sections and angular distributions are derived for both of the above processes. This method was applied to photoionization of the valence levels of three different systems. The first application of this method is a study of the photoionization of the valence levels of NO. Next, vibrationally resolved branching ratios and vibrational state-specific asymmetry parameters for photoionization of the 5sigma level of CO are presented. Finally, a study of the photoionization of the 5sigma level of CO absorbed on a nickel surface is reported. Approximating this system by the linear triatomic molecule NiCO leads to cross sections and angular distributions which are in good agreement with experimental data

  7. Relativistic reconnection in near critical Schwinger field

    Science.gov (United States)

    Schoeffler, Kevin; Grismayer, Thomas; Fonseca, Ricardo; Silva, Luis; Uzdensky, Dmitri

    2017-10-01

    Magnetic reconnection in relativistic pair plasma with QED radiation and pair-creation effects in the presence of strong magnetic fields is investigated using 2D particle-in-cell simulations. The simulations are performed with the QED module of the OSIRIS framework that includes photon emission by electrons and positrons and single photon decay into pairs (non-linear Breit-Wheeler). We investigate the effectiveness of reconnection as a pair- and gamma-ray production mechanism across a broad range of reconnecting magnetic fields, including those approaching the critical quantum (Schwinger) field, and we also explore how the radiative cooling and pair-production processes affect reconnection. We find that in the extreme field regime, the magnetic energy is mostly converted into radiation rather than into particle kinetic energy. This study is a first concrete step towards better understanding of magnetic reconnection as a possible mechanism powering gamma-ray flares in magnetar magnetospheres.

  8. Microscopy of bosonic models using Schwinger and Holstein - Primakoff bosonization techniques

    International Nuclear Information System (INIS)

    Pinto, M.E.B.

    1988-01-01

    Two kinds of bosonic expansions for the SU(2) case, one being finite (Schwinger) and the other being infinite (Holstein-Primakoff) are analysed. The existence of a transformation connecting them was discussed. Utilizing the two methods, the Two Level Model hamiltonian into the many boson space is mapped. Considering systems composed by 4, 6 and 14 particles, calculations for the eigenenergies within the ''vibrational limit'' of the model were performed. The results show that the Schwinger mapping is exact. Approximated bosonic images with the Holstein-Primakoff mapping are obtained. Indeed, the anharmonicities observed in the region between the ideal '' spherical limit'' and the ''transitional point'', were well described by the approximation containing up to quartic terms on the bosonic operators. (author) [pt

  9. Combinatorial Dyson-Schwinger equations and inductive data types

    Science.gov (United States)

    Kock, Joachim

    2016-06-01

    The goal of this contribution is to explain the analogy between combinatorial Dyson-Schwinger equations and inductive data types to a readership of mathematical physicists. The connection relies on an interpretation of combinatorial Dyson-Schwinger equations as fixpoint equations for polynomial functors (established elsewhere by the author, and summarised here), combined with the now-classical fact that polynomial functors provide semantics for inductive types. The paper is expository, and comprises also a brief introduction to type theory.

  10. Schwinger effect in de Sitter space

    Energy Technology Data Exchange (ETDEWEB)

    Fröb, Markus B.; Garriga, Jaume [Departament de Física Fonamental i Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Kanno, Sugumi [Laboratory for Quantum Gravity and Strings and Astrophysics, Cosmology and Gravity Center, Department of Mathematics and Applied Mathematics, University of Cape Town, Private Bag, Rondebosch 7701 (South Africa); Sasaki, Misao; Tanaka, Takahiro [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan); Soda, Jiro [Department of Physics, Kobe University, Kobe 657-8501 (Japan); Vilenkin, Alexander, E-mail: mfroeb@ffn.ub.edu, E-mail: jaume.garriga@ub.edu, E-mail: sugumi.kanno@uct.ac.za, E-mail: misao@yukawa.kyoto-u.ac.jp, E-mail: jiro@phys.sci.kobe-u.ac.jp, E-mail: tanaka@yukawa.kyoto-u.ac.jp, E-mail: vilenkin@cosmos.phy.tufts.edu [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)

    2014-04-01

    We consider Schwinger pair production in 1+1 dimensional de Sitter space, filled with a constant electric field E. This can be thought of as a model for describing false vacuum decay beyond the semiclassical approximation, where pairs of a quantum field φ of mass m and charge e play the role of vacuum bubbles. We find that the adiabatic ''in'' vacuum associated with the flat chart develops a space-like expectation value for the current J, which manifestly breaks the de Sitter invariance of the background fields. We derive a simple expression for J(E), showing that both ''upward'' and ''downward'' tunneling contribute to the build-up of the current. For heavy fields, with m{sup 2} >> eE,H{sup 2}, the current is exponentially suppressed, in agreement with the results of semiclassical instanton methods. Here, H is the inverse de Sitter radius. On the other hand, light fields with m || H lead to a phenomenon of infrared hyperconductivity, where a very small electric field mH∼

  11. Resurgent transseries & Dyson–Schwinger equations

    Energy Technology Data Exchange (ETDEWEB)

    Klaczynski, Lutz, E-mail: klacz@mathematik.hu-berlin.de

    2016-09-15

    We employ resurgent transseries as algebraic tools to investigate two self-consistent Dyson–Schwinger equations, one in Yukawa theory and one in quantum electrodynamics. After a brief but pedagogical review, we derive fixed point equations for the associated anomalous dimensions and insert a moderately generic log-free transseries ansatz to study the possible strictures imposed. While proceeding in various stages, we develop an algebraic method to keep track of the transseries’ coefficients. We explore what conditions must be violated in order to stay clear of fixed point theorems to eschew a unique solution, if so desired, as we explain. An interesting finding is that the flow of data between the different sectors of the transseries shows a pattern typical of resurgence, i.e. the phenomenon that the perturbative sector of the transseries talks to the nonperturbative ones in a one-way fashion. However, our ansatz is not exotic enough as it leads to trivial solutions with vanishing nonperturbative sectors, even when logarithmic monomials are included. We see our result as a harbinger of what future work might reveal about the transseries representations of observables in fully renormalised four-dimensional quantum field theories and adduce a tentative yet to our mind weighty argument as to why one should not expect otherwise. This paper is considerably self-contained. Readers with little prior knowledge are let in on the basic reasons why perturbative series in quantum field theory eventually require an upgrade to transseries. Furthermore, in order to acquaint the reader with the language utilised extensively in this work, we also provide a concise mathematical introduction to grid-based transseries.

  12. Resurgent transseries & Dyson-Schwinger equations

    Science.gov (United States)

    Klaczynski, Lutz

    2016-09-01

    We employ resurgent transseries as algebraic tools to investigate two self-consistent Dyson-Schwinger equations, one in Yukawa theory and one in quantum electrodynamics. After a brief but pedagogical review, we derive fixed point equations for the associated anomalous dimensions and insert a moderately generic log-free transseries ansatz to study the possible strictures imposed. While proceeding in various stages, we develop an algebraic method to keep track of the transseries' coefficients. We explore what conditions must be violated in order to stay clear of fixed point theorems to eschew a unique solution, if so desired, as we explain. An interesting finding is that the flow of data between the different sectors of the transseries shows a pattern typical of resurgence, i.e. the phenomenon that the perturbative sector of the transseries talks to the nonperturbative ones in a one-way fashion. However, our ansatz is not exotic enough as it leads to trivial solutions with vanishing nonperturbative sectors, even when logarithmic monomials are included. We see our result as a harbinger of what future work might reveal about the transseries representations of observables in fully renormalised four-dimensional quantum field theories and adduce a tentative yet to our mind weighty argument as to why one should not expect otherwise. This paper is considerably self-contained. Readers with little prior knowledge are let in on the basic reasons why perturbative series in quantum field theory eventually require an upgrade to transseries. Furthermore, in order to acquaint the reader with the language utilised extensively in this work, we also provide a concise mathematical introduction to grid-based transseries.

  13. Estimations for the Schwinger functions of relativistic quantum field theories

    International Nuclear Information System (INIS)

    Mayer, C.D.

    1981-01-01

    Schwinger functions of a relativistic neutral scalar field the basing test function space of which is S or D are estimated by methods of the analytic continuation. Concerning the behaviour in coincident points it is shown: The two-point singularity of the n-point Schwinger function of a field theory is dominated by an inverse power of the distance of both points modulo a multiplicative constant, if the other n-2 points a sufficiently distant and remain fixed. The power thereby, depends only on n. Using additional conditions on the field the independence of the power on n may be proved. Concerning the behaviour at infinite it is shown: The n-point Schwinger functions of a field theory are globally bounded, if the minimal distance of the arguments is positive. The bound depends only on n and the minimal distance of the arguments. (orig.) [de

  14. A generalized Schwinger boson mapping with a physical subspace

    International Nuclear Information System (INIS)

    Scholtz, F.G.; Geyer, H.B.

    1988-01-01

    We investigate the existence of a physical subspace for generalized Schwinger boson mappings of SO(2n+1) contains SO(2n) in view of previous observations by Marshalek and the recent construction of such a mapping and subspace for SO(8) by Kaup. It is shown that Kaup's construction can be attributed to the existence of a unique SO(8) automorphism. We proceed to construct a generalized Schwinger-type mapping for SO(2n+1) contains SO(2n) which, in contrast to a similar attempt by Yamamura and Nishiyama, indeed has a corresponding physical subspace. This new mapping includes in the special case of SO(8) the mapping by Kaup which is equivalent to the one given by Yamamura and Nishiyama for n=4. Nevertheless, we indicate the limitations of the generalized Schwinger mapping regarding its applicability to situations where one seeks to establish a direct link between phenomenological boson models and an underlying fermion microscopy. (orig.)

  15. Julian Schwinger the physicist, the teacher, and the man

    CERN Document Server

    1996-01-01

    In the post-quantum-mechanics era, few physicists, if any, have matched Julian Schwinger in contributions to and influence on the development of physics. A deep and provocative thinker, Schwinger left his indelible mark on all areas of theoretical physics; an eloquent lecturer and immensely successful mentor, he was gentle, intensely private, and known for being "modest about everything except his physics". This book is a collection of talks in memory of him by some of his contemporaries and his former students: A Klein, F Dyson, B DeWitt, W Kohn, D Saxon, P C Martin, K Johnson, S Deser, R Fin

  16. On the equivalence between the Schwinger and axial models

    International Nuclear Information System (INIS)

    Souza Dutra, A. de.

    1991-01-01

    We show the equivalence between the Schwinger and axial models, in the sense that all Green's functions of one model can be obtained from those of the other, and that both models have the same effective Lagrangian density (and so they have equal partition functions associated with them). In particular, we show that the two models have the same chiral anomaly. Finally it is demonstrated that the Schwinger model can keep gauge invariance for an arbitrary mass, dispensing with an additional gauge group integration. (author)

  17. Resummation of the 1/N-expansion of the non-linear σ-model by Dyson-Schwinger equations

    International Nuclear Information System (INIS)

    Drouffe, J.M.; Flyvbjerg, H.

    1988-02-01

    Dyson-Schwinger equations for the O(N)-symmetric non-linear σ-model are derived and expanded in 1/N. A closed set of equations is obtained by keeping only the leading term and the first correction term in this expansion. These equations are solved numerically in 2 dimensions on square lattices of sizes 50x50 and 100x100. Results for the magnetic susceptibility and the mass gap are compared with predictions of the ordinary 1/N-expansion and with Monte Carlo results. The results obtained with the Dyson-Schwinger equations show the same scaling behavior as found in the Monte Carlo results. This is not the behavior predicted by the perturbative renormalization group. (orig.)

  18. Physical interpretation of Schwinger's formula for effective actions

    International Nuclear Information System (INIS)

    Albuquerque, L.C. de; Farina, C.; Rabello, Silvio J.; Vaidya, Arvind N.

    1994-01-01

    We show explicitly that Schwinger's formula for one-loop effective actions corresponds to the summation of energies associated with the zero-point oscillations of the fields. We begin with a formal proof, and after that we confirm it using a regularization prescription. (author)

  19. Siegel's chiral boson and the chiral Schwinger model

    International Nuclear Information System (INIS)

    Berger, T.

    1992-01-01

    In this paper Siegel's proposal for a Lagrangian formulation of a chiral boson is analyzed by applying recent results on 2d chiral quantum gravity. A model is derived whose solution consists of a massive scalar and two massless chiral scalars. Therefore it is a minimally bosonized two-fermion chiral Schwinger model

  20. Yet another Monte Carlo study of the Schwinger model

    International Nuclear Information System (INIS)

    Sogo, K.; Kimura, N.

    1986-01-01

    Some methodological improvements are introduced in the quantum Monte Carlo simulation of the 1 + 1 dimensional quantum electrodynamics (the Schwinger model). Properties at finite temperatures are investigated, concentrating on the existence of the chirality transition and of the deconfinement transition. (author)

  1. Rarita-Schwinger field and multicomponent wave equation

    International Nuclear Information System (INIS)

    Kaloshin, A.E.; Lomov, V.P.

    2011-01-01

    We suggest a simple method to solve a wave equation for Rarita-Schwinger field without additional constraints. This method based on the use of off-shell projection operators allows one to diagonalize spin-1/2 sector of the field

  2. Yet another Monte Carlo study of the Schwinger model

    International Nuclear Information System (INIS)

    Sogo, K.; Kimura, N.

    1986-03-01

    Some methodological improvements are introduced in the quantum Monte Carlo simulation of the 1 + 1 dimensional quantum electrodynamics (the Schwinger model). Properties at finite temperatures are investigated, concentrating on the existence of the chirality transition and of the deconfinement transition. (author)

  3. Large Wilson loop averages from the Schwinger-Dyson equation

    International Nuclear Information System (INIS)

    Xue Shesheng

    1987-01-01

    Using Schwinger-Dyson equations for the large Wilson loop in abelian lattice gauge theories, we evaluate the vacuum expectation values of the Wilson loop of sizes 1x2, 2x2, 2x3, and so on, from which the string tension is extracted. (orig.)

  4. Comparison of Schwinger and Kohn variational phase shift calculations

    International Nuclear Information System (INIS)

    Callaway, I.

    1980-01-01

    Numerical calculations of the l = 0 phase shift for an attractive Yukawa potential are reported using Schwinger and Kohn (type) variational methods. Accurate values can be obtained from both procedures, but when the same basis set of short range functions is used, the Kohn procedure gives superior results. (orig.)

  5. Extended Hamiltonian formalism of the pure space-like axial gauge Schwinger model

    International Nuclear Information System (INIS)

    Nakawaki, Yuji; Mccartor, Gary

    2001-01-01

    We demonstrate that pure space-like axial gauge quantizations of gauge fields can be constructed in ways that are free from infrared divergences. To do so, we must extend the Hamiltonian formalism to include residual gauge fields. We construct an operator solution and an extended Hamiltonian of the pure space-like axial gauge Schwinger model. We begin by constructing an axial gauge formation in auxiliary coordinates, x μ =(x + , x - ), where x + =x 0 sinθ + x 1 cosθ, x - =x 0 cosθ - x 1 sinθ, and we take A=A 0 cosθ + A 1 sin θ=0 as the gauge fixing condition. In the region 0 - as the evolution parameter and construct a traditional canonical formulation of the temporal gauge Schwinger model in which residual gauge fields dependent only on x + are static canonical variables. Then we extrapolate the temporal gauge operator solution into the axial region, π / 4 + is taken as the evolution parameter. In the axial region we find that we have to take the representation of the residual gauge fields realizing the Mandelstam-Leibbrandt prescription in order for the infrared divergences resulting from (∂) -1 to be canceled by corresponding ones resulting from the inverse of the hyperbolic Laplace operator. We overcome the difficulty of constructing the Hamiltonian for the residual gauge fields by employing McCartor and Robertson's method, which gives us a term integrated over x - =constant. Finally, by taking the limit θ→π / 2 - 0, we obtain an operator solution and the Hamiltonian of the axial gauge (Coulomb gauge) Schwinger model in ordinary coordinates. That solution includes auxiliary fields, and the representation space is of indefinite metric, providing further evidence that 'physical' gauges are no more physical than 'unphysical' gauges. (author)

  6. From the Dyson-Schwinger to the Transport Equation in the Background Field Gauge of QCD

    CERN Document Server

    Wang, Q; Stöcker, H; Greiner, W

    2003-01-01

    The non-equilibrium quantum field dynamics is usually described in the closed-time-path formalism. The initial state correlations are introduced into the generating functional by non-local source terms. We propose a functional approach to the Dyson-Schwinger equation, which treats the non-local and local source terms in the same way. In this approach, the generating functional is formulated for the connected Green functions and one-particle-irreducible vertices. The great advantages of our approach over the widely used two-particle-irreducible method are that it is much simpler and that it is easy to implement the procedure in a computer program to automatically generate the Feynman diagrams for a given process. The method is then applied to a pure gluon plasma to derive the gauge-covariant transport equation from the Dyson-Schwinger equation in the background covariant gauge. We discuss the structure of the kinetic equation and show its relationship with the classical one. We derive the gauge-covariant colli...

  7. The generalized chiral Schwinger model on the two-sphere

    International Nuclear Information System (INIS)

    Bassetto, A.

    1995-01-01

    A family of theories which interpolate between vector and chiral Schwinger models is studied on the two-sphere S 2 . The conflict between the loss of gauge invariance and global geometrical properties is solved by introducing a fixed background connection. In this way the generalized Dirac-Weyl operator can be globally defined on S 2 . The generating functional of the Green functions is obtained by taking carefully into account the contribution of gauge fields with non-trivial topological charge and of the related zero-modes of the Dirac determinant. In the decompactification limit, the Green functions of the flat case are recovered; in particular the fermionic condensate in the vacuum vanishes, at variance with its behaviour in the vector Schwinger model. ((orig.))

  8. Gauge-invariant masses through Schwinger-Dyson equations

    International Nuclear Information System (INIS)

    Bashir, A.; Raya, A.

    2007-01-01

    Schwinger-Dyson equations (SDEs) are an ideal framework to study non-perturbative phenomena such as dynamical chiral symmetry breaking (DCSB). A reliable truncation of these equations leading to gauge invariant results is a challenging problem. Constraints imposed by Landau-Khalatnikov-Fradkin transformations (LKFT) can play an important role in the hunt for physically acceptable truncations. We present these constrains in the context of dynamical mass generation in QED in 2 + 1-dimensions

  9. Correlation functions and Schwinger-Dyson equations for Penner's model

    International Nuclear Information System (INIS)

    Chair, N.; Panda, S.

    1991-05-01

    The free energy of Penner's model exhibits logarithmic singularity in the continuum limit. We show, however, that the one and two point correlators of the usual loop-operators do not exhibit logarithmic singularity. The continuum Schwinger-Dyson equations involving these correlation functions are derived and it is found that within the space of the corresponding couplings, the resulting constraints obey a Virasoro algebra. The puncture operator having the correct (logarithmic) scaling behaviour is identified. (author). 13 refs

  10. The geometric Schwinger model on the torus. Pt. 1

    International Nuclear Information System (INIS)

    Joos, H.

    1990-01-01

    The author analyzes the Euclidean version of the geometric Schwinger model on the torus. After the calculation of the zero mode wave functions associated with the different topological sectors, which can be expressed by θ functions defined on the two-dimensional torus, he determines the regularized effective action and discusses the propagator related to it. Finally he studies applications to the standard questions like the particle spectrum, the screening of the static potential, and the appearance of the anomaly. (HSI)

  11. Comparison of the anomalous and non-anomalous generalized Schwinger models via functional formalism

    International Nuclear Information System (INIS)

    Souza Dutra, A. de.

    1992-01-01

    The Green functions of the two versions of the two versions of the generalized Schwinger model, the anomalous and the non-anomalous one, in their higher order Lagrangian density form are calculated. Furthermore it is shown through a sequence of transformations that the bosonized Lagrangian density is equivalent to the former, at least for the bosonic correlation functions. The introduction of the sources from the beginning, leading to a gauge-invariant source term is also considered. It is verified that the two models have the same correlation functions only of the gauge-invariant sector is taken into account. Finally it is presented a generalization of the Wess-Zumino term, and its physical consequences are studied, in particular the appearance of gauge-dependent massive excitations. (author)

  12. A Dyson-Schwinger approach to finite temperature QCD

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Jens Andreas

    2011-10-26

    The different phases of quantum chromodynamics at finite temperature are studied. To this end the nonperturbative quark propagator in Matsubara formalism is determined from its equation of motion, the Dyson-Schwinger equation. A novel truncation scheme is introduced including the nonperturbative, temperature dependent gluon propagator as extracted from lattice gauge theory. In the first part of the thesis a deconfinement order parameter, the dual condensate, and the critical temperature are determined from the dependence of the quark propagator on the temporal boundary conditions. The chiral transition is investigated by means of the quark condensate as order parameter. In addition differences in the chiral and deconfinement transition between gauge groups SU(2) and SU(3) are explored. In the following the quenched quark propagator is studied with respect to a possible spectral representation at finite temperature. In doing so, the quark propagator turns out to possess different analytic properties below and above the deconfinement transition. This result motivates the consideration of an alternative deconfinement order parameter signaling positivity violations of the spectral function. A criterion for positivity violations of the spectral function based on the curvature of the Schwinger function is derived. Using a variety of ansaetze for the spectral function, the possible quasi-particle spectrum is analyzed, in particular its quark mass and momentum dependence. The results motivate a more direct determination of the spectral function in the framework of Dyson-Schwinger equations. In the two subsequent chapters extensions of the truncation scheme are considered. The influence of dynamical quark degrees of freedom on the chiral and deconfinement transition is investigated. This serves as a first step towards a complete self-consistent consideration of dynamical quarks and the extension to finite chemical potential. The goodness of the truncation is verified first

  13. A Dyson-Schwinger approach to finite temperature QCD

    International Nuclear Information System (INIS)

    Mueller, Jens Andreas

    2011-01-01

    The different phases of quantum chromodynamics at finite temperature are studied. To this end the nonperturbative quark propagator in Matsubara formalism is determined from its equation of motion, the Dyson-Schwinger equation. A novel truncation scheme is introduced including the nonperturbative, temperature dependent gluon propagator as extracted from lattice gauge theory. In the first part of the thesis a deconfinement order parameter, the dual condensate, and the critical temperature are determined from the dependence of the quark propagator on the temporal boundary conditions. The chiral transition is investigated by means of the quark condensate as order parameter. In addition differences in the chiral and deconfinement transition between gauge groups SU(2) and SU(3) are explored. In the following the quenched quark propagator is studied with respect to a possible spectral representation at finite temperature. In doing so, the quark propagator turns out to possess different analytic properties below and above the deconfinement transition. This result motivates the consideration of an alternative deconfinement order parameter signaling positivity violations of the spectral function. A criterion for positivity violations of the spectral function based on the curvature of the Schwinger function is derived. Using a variety of ansaetze for the spectral function, the possible quasi-particle spectrum is analyzed, in particular its quark mass and momentum dependence. The results motivate a more direct determination of the spectral function in the framework of Dyson-Schwinger equations. In the two subsequent chapters extensions of the truncation scheme are considered. The influence of dynamical quark degrees of freedom on the chiral and deconfinement transition is investigated. This serves as a first step towards a complete self-consistent consideration of dynamical quarks and the extension to finite chemical potential. The goodness of the truncation is verified first

  14. Nonadiabatic quantum Vlasov equation for Schwinger pair production

    International Nuclear Information System (INIS)

    Kim, Sang Pyo; Schubert, Christian

    2011-01-01

    Using Lewis-Riesenfeld theory, we derive an exact nonadiabatic master equation describing the time evolution of the QED Schwinger pair-production rate for a general time-varying electric field. This equation can be written equivalently as a first-order matrix equation, as a Vlasov-type integral equation, or as a third-order differential equation. In the last version it relates to the Korteweg-de Vries equation, which allows us to construct an exact solution using the well-known one-soliton solution to that equation. The case of timelike delta function pulse fields is also briefly considered.

  15. Schwinger mechanism in electromagnetic field in de Sitter spacetime

    Directory of Open Access Journals (Sweden)

    Bavarsad Ehsan

    2018-01-01

    Full Text Available We investigate Schwinger scalar pair production in a constant electromagnetic field in de Sitter (dS spacetime. We obtain the pair production rate, which agrees with the Hawking radiation in the limit of zero electric field in dS. The result describes how a cosmic magnetic field affects the pair production rate. In addition, using a numerical method we study the effect of the magnetic field on the induced current. We find that in the strong electromagnetic field the current has a linear response to the electric and magnetic fields, while in the infrared regime, is inversely proportional to the electric field and leads to infrared hyperconductivity.

  16. Critical behavior of the Schwinger model with Wilson fermions

    International Nuclear Information System (INIS)

    Azcoiti, V.; Laliena, V.

    1995-09-01

    A detailed analysis, in the framework of the MFA approach, of the critical behaviour of the lattice Schwinger model with Wilson fermions on lattices up to 24 2 , through the study of the Lee-Yang zeros and the specific heat, is presented. Compelling evidence is found for a critical line ending at k= 0.25 at large β. Finite size scaling analysis on lattices 8 2 , 12 2 , 16 2 , 20 2 and 24 2 indicates a continuous transition. The hyper scaling relation is verified in the explored β region

  17. Effects of strain on the Schwinger pair creation in graphene

    International Nuclear Information System (INIS)

    Fanbanrai, P.; Hutem, A.; Boonchui, S.

    2015-01-01

    The effects of strain on mechanically deformed graphene are determined by looking at how the strain affects the amplitude of the Schwinger two particle pair state. The influences of the lattice distortions, such as isotropic tensile strain ϵ is , shear strain ϵ ss , uniaxial armchair strain ϵ as , and zigzag strain ϵ zs , on the photon emission spectrum have been analyzed. We find that the intensities of the emission increases or decreases when compared to those of the unstrained graphene, depending on the type of strain applied. Thus the structure of energy band, the frequencies of the photons and the emission spectrum can be controlled by use of the different strains

  18. Schwinger-Keldysh propagators from AdS/CFT correspondence

    International Nuclear Information System (INIS)

    Herzog, C.P.; Son, D.T.

    2003-01-01

    We demonstrate how to compute real-time Green's functions for a class of finite temperature field theories from their AdS gravity duals. In particular, we reproduce the two-by-two Schwinger-Keldysh matrix propagator from a gravity calculation. Our methods should work also for computing higher point lorentzian signature correlators. We elucidate the boundary condition subtleties which hampered previous efforts to build a lorentzian-signature AdS/CFT correspondence. For two-point correlators, our construction is automatically equivalent to the previously formulated prescription for the retarded propagator. (author)

  19. Schwinger Dyson equations: Dynamical chiral symmetry breaking and confinement

    International Nuclear Information System (INIS)

    Roberts, C.D.

    1992-01-01

    A representative but not exhaustive review of the Schwinger-Dyson equation (SDE) approach to the nonperturbative study of QCD is presented. The main focus is the SDE for the quark self energy but studies of the gluon propagator and quark-gluon vertex are also discussed insofar as they are important to the quark SDE. The scope of this article is the application of these equations to the study of dynamical chiral symmetry breaking, quark confinement and the phenomenology of the spectrum and dynamics of QCD

  20. Schwinger effect and negative differential conductivity in holographic models

    Directory of Open Access Journals (Sweden)

    Shankhadeep Chakrabortty

    2015-01-01

    Full Text Available The consequences of the Schwinger effect for conductivity are computed for strong coupling systems using holography. The one-loop diagram on the flavor brane introduces an O(λNc imaginary part in the effective action for a Maxwell flavor gauge field. This in turn introduces a real conductivity in an otherwise insulating phase of the boundary theory. Moreover, in certain regions of parameter space the differential conductivity is negative. This is computed in the context of the Sakai–Sugimoto model.

  1. The Jordan-Schwinger realization of two-parametric quantum group Slq,s(2)

    International Nuclear Information System (INIS)

    Jing Sicong.

    1991-10-01

    In order to construct the Jordan-Schwinger realization for two-parametric quantum group Sl q,s (2), two independent q, s-deformed harmonic oscillators are defined in this paper and the Heisenberg commutation relations of the q, s-deformed oscillator are also derived by Schwinger's contraction procedure. (author). 11 refs

  2. Towards loop quantum supergravity (LQSG): I. Rarita–Schwinger sector

    International Nuclear Information System (INIS)

    Bodendorfer, N; Thiemann, T; Thurn, A

    2013-01-01

    In our companion papers, we managed to derive a connection formulation of Lorentzian general relativity in D + 1 dimensions with compact gauge group SO(D + 1) such that the connection is Poisson-commuting, which implies that loop quantum gravity quantization methods apply. We also provided the coupling to standard matter. In this paper, we extend our methods to derive a connection formulation of a large class of Lorentzian signature supergravity theories, in particular 11 D SUGRA and 4 D, N = 8 SUGRA, which was in fact the motivation to consider higher dimensions. Starting from a Hamiltonian formulation in the time gauge which yields a Spin(D) theory, a major challenge is to extend the internal gauge group to Spin(D + 1) in the presence of the Rarita–Schwinger field. This is non-trivial because SUSY typically requires the Rarita–Schwinger field to be a Majorana fermion for the Lorentzian Clifford algebra and Majorana representations of the Clifford algebra are not available in the same spacetime dimension for both Lorentzian and Euclidean signatures. We resolve the arising tension and provide a background-independent representation of the non-trivial Dirac antibracket *-algebra for the Majorana field which significantly differs from the analogous construction for Dirac fields already available in the literature. (paper)

  3. Off-diagonal coefficients of the DeWitt-Schwinger and Hadamard representations of the Feynman propagator

    International Nuclear Information System (INIS)

    Decanini, Yves; Folacci, Antoine

    2006-01-01

    Having in mind applications to gravitational wave theory (in connection with the radiation reaction problem), stochastic semiclassical gravity (in connection with the regularization of the noise kernel) and quantum field theory in higher-dimensional curved spacetime (in connection with the Hadamard regularization of the stress-energy tensor), we improve the DeWitt-Schwinger and Hadamard representations of the Feynman propagator of a massive scalar field theory defined on an arbitrary gravitational background by deriving higher-order terms for the covariant Taylor series expansions of the geometrical coefficients--i.e., the DeWitt and Hadamard coefficients--that define them

  4. Determining partial differential cross sections for low-energy electron photodetachment involving conical intersections using the solution of a Lippmann-Schwinger equation constructed with standard electronic structure techniques.

    Science.gov (United States)

    Han, Seungsuk; Yarkony, David R

    2011-05-07

    A method for obtaining partial differential cross sections for low energy electron photodetachment in which the electronic states of the residual molecule are strongly coupled by conical intersections is reported. The method is based on the iterative solution to a Lippmann-Schwinger equation, using a zeroth order Hamiltonian consisting of the bound nonadiabatically coupled residual molecule and a free electron. The solution to the Lippmann-Schwinger equation involves only standard electronic structure techniques and a standard three-dimensional free particle Green's function quadrature for which fast techniques exist. The transition dipole moment for electron photodetachment, is a sum of matrix elements each involving one nonorthogonal orbital obtained from the solution to the Lippmann-Schwinger equation. An expression for the electron photodetachment transition dipole matrix element in terms of Dyson orbitals, which does not make the usual orthogonality assumptions, is derived.

  5. Fermion structures of state vectors of the Schwinger model with multi-fermions

    International Nuclear Information System (INIS)

    Nakawaki, Yuji

    1983-01-01

    Coulomb-gauge Schwinger model with multi-fermions is formulated consistently in a box [-L, L] by introducing true dynamical degrees of freedom of electromagnetic fields, namely zero-mode part A 1 sup((0)) of A 1 and its canonical conjugate momentum π 1 sup((0)). State vectors are constructed of free massless fermion operators and zero-mode operators A 1 sup((0)) and π 1 sup((0)) and it is clarified how and why multifermion condensations become degenerate ground states and chiral invariance is spontaneously broken. It is also examined that physical space of covariant gauge Schwinger model is isomorphic to that of Coulomb-gauge Schwinger model. (author)

  6. Dynamically assisted Sauter-Schwinger effect in inhomogeneous electric fields

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Christian; Schützhold, Ralf [Fakultät für Physik, Universität Duisburg-Essen,Lotharstrasse 1, 47057 Duisburg (Germany)

    2016-02-24

    Via the world-line instanton method, we study electron-positron pair creation by a strong (but sub-critical) electric field of the profile E/cosh{sup 2} (kx) superimposed by a weaker pulse E{sup ′}/cosh{sup 2} (ωt). If the temporal Keldysh parameter γ{sub ω}=mω/(qE) exceeds a threshold value γ{sub ω}{sup crit} which depends on the spatial Keldysh parameter γ{sub k}=mk/(qE), we find a drastic enhancement of the pair creation probability — reporting on what we believe to be the first analytic non-perturbative result for the interplay between temporal and spatial field dependences E(t,x) in the Sauter-Schwinger effect. Finally, we speculate whether an analogous effect (drastic enhancement of tunneling probability) could occur in other scenarios such as stimulated nuclear decay, for example.

  7. Schwinger type processes via branes and their gravity duals

    International Nuclear Information System (INIS)

    Gorsky, A.S.; Saraikin, K.A.; Selivanov, K.G.

    2002-01-01

    We consider Schwinger type processes involving the creation of the charge and monopole pairs in the external fields and propose interpretation of these processes via corresponding brane configurations in type IIB string theory. We suggest simple description of some new interesting nonperturbative processes like monopole/dyon transitions in the electric field and W-boson decay in the magnetic field using the brane language. Nonperturbative pair production in the strong coupling regime using the AdS/CFT correspondence is studied. The treatment of the similar processes in the noncommutative theories when noncommutativity is traded for the background fields is presented and the possible role of the critical magnetic field which is S-dual to the critical electric field is discussed

  8. Thermal evolution of the Schwinger model with matrix product operators

    International Nuclear Information System (INIS)

    Banuls, M.C.; Cirac, J.I.; Cichy, K.; Jansen, K.; Saito, H.

    2015-10-01

    We demonstrate the suitability of tensor network techniques for describing the thermal evolution of lattice gauge theories. As a benchmark case, we have studied the temperature dependence of the chiral condensate in the Schwinger model, using matrix product operators to approximate the thermal equilibrium states for finite system sizes with non-zero lattice spacings. We show how these techniques allow for reliable extrapolations in bond dimension, step width, system size and lattice spacing, and for a systematic estimation and control of all error sources involved in the calculation. The reached values of the lattice spacing are small enough to capture the most challenging region of high temperatures and the final results are consistent with the analytical prediction by Sachs and Wipf over a broad temperature range.

  9. Quantum mechanics on Riemannian manifold in Schwinger's quantization approach II

    International Nuclear Information System (INIS)

    Chepilko, N.M.; Romanenko, A.V.

    2001-01-01

    The extended Schwinger quantization procedure is used for constructing quantum mechanics on a manifold with a group structure. The considered manifold M is a homogeneous Riemannian space with the given action of an isometry transformation group. Using the identification of M with the quotient space G/H, where H is the isotropy group of an arbitrary fixed point of M, we show that quantum mechanics on G/H possesses a gauge structure, described by a gauge potential that is the connection 1-form of the principal fiber bundle G(G/H, H). The coordinate representation of quantum mechanics and the procedure for selecting the physical sector of the states are developed. (orig.)

  10. The gravitational Schwinger effect and attenuation of gravitational waves

    Science.gov (United States)

    McDougall, Patrick Guarneri

    This paper will discuss the possible production of photons from gravitational waves. This process is shown to be possible by examining Feynman diagrams, the Schwinger Effect, and Hawking Radiation. The end goal of this project is to find the decay length of a gravitational wave and assert that this decay is due to photons being created at the expense of the gravitational wave. To do this, we first find the state function using the Klein Gordon equation, then find the current due to this state function. We then take the current to be directly proportional to the production rate per volume. This is then used to find the decay length that this kind of production would produce, gives a prediction of how this effect will change the distance an event creating a gravitational wave will be located, and shows that this effect is small but can be significant near the source of a gravitational wave.

  11. Heavy meson observables and Dyson-Schwinger equations

    International Nuclear Information System (INIS)

    Ivanov, M. A.

    1998-01-01

    Dyson-Schwinger equation (DSE) studies show that the b-quark mass-function is approximately constant, and that this is true to a lesser extent for the c-quark. This observation provides the basis for a study of the leptonic and semileptonic decays of heavy pseudoscalar mesons using a ''heavy-quark'' limit of the DSES, which, when exact, reduces the number of independent form factors. Semileptonic decays with light mesons in the final state are also accessible because the DSES provide a description of light-quark propagation characteristics and light-meson structure. A description of B-meson decays is straightforward, however, the study of decays involving the D-meson indicates that c-quark mass-corrections are quantitatively important

  12. Spectator electric fields, de Sitter spacetime, and the Schwinger effect

    Science.gov (United States)

    Giovannini, Massimo

    2018-03-01

    During a de Sitter stage of expansion, the spectator fields of different spin are constrained by the critical density bound and by further requirements determined by their specific physical nature. The evolution of spectator electric fields in conformally flat background geometries is occasionally concocted by postulating the existence of ad hoc currents, but this apparently innocuous trick violates the second law of thermodynamics. Such a problem occurs, in particular, for those configurations (customarily employed for the analysis of the Schwinger effect in four-dimensional de Sitter backgrounds) leading to an electric energy density which is practically unaffected by the expansion of the underlying geometry. The obtained results are compared with more mundane situations where Joule heating develops in the early stages of a quasi-de Sitter phase.

  13. Schwinger's formula and the partition function for the bosonic and fermionic harmonic oscillators

    International Nuclear Information System (INIS)

    Albuquerque, L.C. de; Farina, C.; Rabello, S.J.

    1994-01-01

    We use Schwinger's formula, introduced by himself in the early fifties to compute effective actions for Qed, and recently applied to the Casimir effect, to obtain the partition functions for both the bosonic and fermionic harmonic oscillators. (author)

  14. Dyson-Schwinger equations for the non-linear σ-model

    International Nuclear Information System (INIS)

    Drouffe, J.M.; Flyvbjerg, H.

    1989-08-01

    Dyson-Schwinger equations for the O(N)-symmetric non-linear σ-model are derived. They are polynomials in N, hence 1/N-expanded ab initio. A finite, closed set of equations is obtained by keeping only the leading term and the first correction term in this 1/N-series. These equations are solved numerically in two dimensions on square lattices measuring 50x50, 100x100, 200x200, and 400x400. They are also solved analytically at strong coupling and at weak coupling in a finite volume. In these two limits the solution is asymptotically identical to the exact strong- and weak-coupling series through the first three terms. Between these two limits, results for the magnetic susceptibility and the mass gap are identical to the Monte Carlo results available for N=3 and N=4 within a uniform systematic error of O(1/N 3 ), i.e. the results seem good to O(1/N 2 ), though obtained from equations that are exact only to O(1/N). This is understood by seeing the results as summed infinite subseries of the 1/N-series for the exact susceptibility and mass gap. We conclude that the kind of 1/N-expansion presented here converges as well as one might ever hope for, even for N as small as 3. (orig.)

  15. Color-superconductivity from a Dyson-Schwinger perspective

    Energy Technology Data Exchange (ETDEWEB)

    Nickel, M.D.J.

    2007-12-20

    Color-superconducting phases of quantum chromodynamics at vanishing temperatures and high densities are investigated. The central object is the one-particle Green's function of the fermions, the so-called quark propagator. It is determined by its equation of motion, the Dyson-Schwinger equation. To handle Dyson-Schwinger equations a successfully applied truncation scheme in the vacuum is extended to finite densities and gradually improved. It is thereby guaranteed that analytical results at asymptotically large densities are reproduced. This way an approach that is capable to describe known results in the vacuum as well as at high densities is applied to densities of astrophysical relevance for the first time. In the first part of the thesis the framework of the investigations with focus on the extension to finite densities is outlined. Physical observables are introduced which can be extracted from the propagator. In the following a minimal truncation scheme is presented. To point out the complexity of our approach in comparison to phenomenological models of quantum chromodynamics the chirally unbroken phase is discussed first. Subsequently color-superconducting phases for massless quarks are investigated. Furthermore the role of finite quark masses and neutrality constraints at moderate densities is studied. In contrast to phenomenological models the so-called CFL phase is found to be the ground state for all relevant densities. In the following part the applicability of the maximum entropy method for the extraction of spectral functions from numerical results in Euclidean space-time is demonstrated. As an example the spectral functions of quarks in the chirally unbroken and color-superconducting phases are determined. Hereby the results of our approach are presented in a new light. For instance the finite width of the quasiparticles in the color-superconducting phase becomes apparent. In the final chapter of this work extensions of our truncation scheme in

  16. Color-superconductivity from a Dyson-Schwinger perspective

    International Nuclear Information System (INIS)

    Nickel, M.D.J.

    2007-01-01

    Color-superconducting phases of quantum chromodynamics at vanishing temperatures and high densities are investigated. The central object is the one-particle Green's function of the fermions, the so-called quark propagator. It is determined by its equation of motion, the Dyson-Schwinger equation. To handle Dyson-Schwinger equations a successfully applied truncation scheme in the vacuum is extended to finite densities and gradually improved. It is thereby guaranteed that analytical results at asymptotically large densities are reproduced. This way an approach that is capable to describe known results in the vacuum as well as at high densities is applied to densities of astrophysical relevance for the first time. In the first part of the thesis the framework of the investigations with focus on the extension to finite densities is outlined. Physical observables are introduced which can be extracted from the propagator. In the following a minimal truncation scheme is presented. To point out the complexity of our approach in comparison to phenomenological models of quantum chromodynamics the chirally unbroken phase is discussed first. Subsequently color-superconducting phases for massless quarks are investigated. Furthermore the role of finite quark masses and neutrality constraints at moderate densities is studied. In contrast to phenomenological models the so-called CFL phase is found to be the ground state for all relevant densities. In the following part the applicability of the maximum entropy method for the extraction of spectral functions from numerical results in Euclidean space-time is demonstrated. As an example the spectral functions of quarks in the chirally unbroken and color-superconducting phases are determined. Hereby the results of our approach are presented in a new light. For instance the finite width of the quasiparticles in the color-superconducting phase becomes apparent. In the final chapter of this work extensions of our truncation scheme in

  17. Hamiltonian approach to the lattice massive Schwinger model

    International Nuclear Information System (INIS)

    Sidorov, A.V.; Zastavenko, L.G.

    1996-01-01

    The authors consider the limit e 2 /m 2 much-lt 1 of the lattice massive Schwinger model, i.e., the lattice massive QED in two space-time dimensions, up to lowest order in the effective coupling constant e 2 /m 2 . Here, m is the fermion mass parameter and e is the electron charge. They compare their lattice QED model with the analogous continuous space and lattice space models, (CSM and LSM), which do not take account of the zero momentum mode, z.m.m., of the vector potential. The difference is that (due to extra z.m.m. degree of freedom) to every eigenstate of the CSM and LSM there corresponds a family of eigenstates of the authors lattice QED with the parameter λ. They restrict their consideration to small values of the parameter λ. Then, the energies of the particle states of their lattice QED and LSM do coincide (in their approximation). In the infinite periodicity length limit the Hamiltonian of the authors lattice QED (as well as the Hamiltonian of the LSM) possesses two different Hilbert spaces of eigenfunctions. Thus, in this limit the authors lattice QED model (as well as LSM) describes something like two connected, but different, worlds

  18. Infrared behaviour, sources and the Schwinger action principle

    International Nuclear Information System (INIS)

    Burgess, M.

    1994-05-01

    An action principle technique is used to explore some issues concerning the infra-red problem in the effective action for gauge field theories. The relationship between the renormalization group and other non-perturbative resummation schemes is demonstrated by means of a source theory. It is shown that the use of vertex renormalization conditions and other resummation methods (large N expansion) can lead to erroneous conclusions about the phase transitions in the gauge theory, since it corresponds to only a partial resummation of the scalar self-energies at the expense of the gauge sector. The renormalization group as well as the ansatz of non-local sources can be derived from an associated operator problem for the field couplings by use of the Schwinger action principle. This method generalizes to curved spacetime and non-equilibrium models in a straightforward way. Some examples are computed to lowest order and the conclusion is drawn that none of the approximation schemes are able to extract true non-perturbative information from field theory. Only results which rely on the particular recursive structure of the perturbation series are accessible and the main purpose of the investigation is to determine legal ways of regulating the theory in the infrared. 35 refs

  19. Quantum Simulation of a Lattice Schwinger Model in a Chain of Trapped Ions

    Directory of Open Access Journals (Sweden)

    P. Hauke

    2013-11-01

    Full Text Available We discuss how a lattice Schwinger model can be realized in a linear ion trap, allowing a detailed study of the physics of Abelian lattice gauge theories related to one-dimensional quantum electrodynamics. Relying on the rich quantum-simulation toolbox available in state-of-the-art trapped-ion experiments, we show how one can engineer an effectively gauge-invariant dynamics by imposing energetic constraints, provided by strong Ising-like interactions. Applying exact diagonalization to ground-state and time-dependent properties, we study the underlying microscopic model and discuss undesired interaction terms and other imperfections. As our analysis shows, the proposed scheme allows for the observation in realistic setups of spontaneous parity- and charge-symmetry breaking, as well as false-vacuum decay. Besides an implementation aimed at larger ion chains, we also discuss a minimal setting, consisting of only four ions in a simpler experimental setup, which enables us to probe basic physical phenomena related to the full many-body problem. The proposal opens a new route for analog quantum simulation of high-energy and condensed-matter models where gauge symmetries play a prominent role.

  20. Spectral representation of the particle production out of equilibrium—Schwinger mechanism in pulsed electric fields

    International Nuclear Information System (INIS)

    Fukushima, Kenji

    2014-01-01

    We develop a formalism to describe the particle production out of equilibrium in terms of dynamical spectral functions, i.e. Wigner transformed Pauli–Jordan's and Hadamard's functions. We take an explicit example of a spatially homogeneous scalar theory under pulsed electric fields and investigate the time evolution of the spectral functions. In the out-state we find an oscillatory peak in Hadamard's function as a result of the mixing between positive- and negative-energy waves. The strength of this peak is of the linear order of the Bogoliubov mixing coefficient, whereas the peak corresponding to the Schwinger mechanism is of the quadratic order. Between the in- and the out-states we observe a continuous flow of the spectral peaks together with two transient oscillatory peaks. We also discuss the medium effect at finite temperature and density. We emphasize that the entire structure of the spectral functions conveys rich information on real-time dynamics including the particle production. (paper)

  1. Alien calculus and a Schwinger-Dyson equation: two-point function with a nonperturbative mass scale

    Science.gov (United States)

    Bellon, Marc P.; Clavier, Pierre J.

    2018-02-01

    Starting from the Schwinger-Dyson equation and the renormalization group equation for the massless Wess-Zumino model, we compute the dominant nonperturbative contributions to the anomalous dimension of the theory, which are related by alien calculus to singularities of the Borel transform on integer points. The sum of these dominant contributions has an analytic expression. When applied to the two-point function, this analysis gives a tame evolution in the deep euclidean domain at this approximation level, making doubtful the arguments on the triviality of the quantum field theory with positive β -function. On the other side, we have a singularity of the propagator for timelike momenta of the order of the renormalization group invariant scale of the theory, which has a nonperturbative relationship with the renormalization point of the theory. All these results do not seem to have an interpretation in terms of semiclassical analysis of a Feynman path integral.

  2. Hadronic bound states in SU(2) from Dyson-Schwinger equations

    Energy Technology Data Exchange (ETDEWEB)

    Vujinovic, Milan [Karl-Franzens-Universitaet Graz, Institut fuer Physik, Graz (Austria); Williams, Richard [Justus-Liebig-Universitaet Giessen, Institut fuer Theoretische Physik, Giessen (Germany)

    2015-03-01

    By using the Dyson-Schwinger/Bethe-Salpeter formalism in Euclidean spacetime, we calculate the ground state spectrum of J ≤ 1 hadrons in an SU(2) gauge theory with two fundamental fermions. We show that the rainbow-ladder truncation, commonly employed in QCD studies, is unsuitable for a description of an SU(2) theory. This we remedy by truncating at the level of the quark-gluon vertex Dyson-Schwinger equation in a diagrammatic expansion. Results obtained within this novel approach show good agreement with lattice studies. These findings emphasize the need to use techniques more sophisticated than rainbow-ladder when investigating generic strongly interacting gauge theories. (orig.)

  3. Schwinger pair creation of Kaluza-Klein particles: Pair creation without tunneling

    International Nuclear Information System (INIS)

    Friedmann, Tamar; Verlinde, Herman

    2005-01-01

    We study Schwinger pair creation of charged Kaluza-Klein (KK) particles from a static KK electric field. We find that the gravitational backreaction of the electric field on the geometry--which is incorporated via the electric KK-Melvin solution--prevents the electrostatic potential from overcoming the rest mass of the KK particles, thus impeding the tunneling mechanism which is often thought of as responsible for the pair creation. However, we find that pair creation still occurs with a finite rate formally similar to the classic Schwinger result, but via an apparently different mechanism, involving a combination of the Unruh effect and vacuum polarization due to the E-field

  4. Faddeev-Jackiw Hamiltonian reduction for free and gauged Rarita-Schwinger theories

    Energy Technology Data Exchange (ETDEWEB)

    Dengiz, Suat [Massachusetts Institute of Technology, Center for Theoretical Physics, Cambridge, MA (United States)

    2016-10-15

    We study the Faddeev-Jackiw symplectic Hamiltonian reduction for 3 + 1-dimensional free and Abelian gauged Rarita-Schwinger theories that comprise Grassmannian fermionic fields. We obtain the relevant fundamental brackets and find that they are in convenient forms for quantization. The brackets are independent of whether the theories contain mass or gauge fields, and the structures of constraints and symplectic potentials largely determine characteristic behaviors of the theories. We also note that, in contrast to the free massive theory, the Dirac field equations for free massless Rarita-Schwinger theory cannot be obtained in a covariant way. (orig.)

  5. Electromagnetic Radiation : Variational Methods, Waveguides and Accelerators Including seminal papers of Julian Schwinger

    CERN Document Server

    Milton, Kimball A

    2006-01-01

    This is a graduate level textbook on the theory of electromagnetic radiation and its application to waveguides, transmission lines, accelerator physics and synchrotron radiation. It has grown out of lectures and manuscripts by Julian Schwinger prepared during the war at MIT's Radiation Laboratory, updated with material developed by Schwinger at UCLA in the 1970s and 1980s, and by Milton at the University of Oklahoma since 1994. The book includes a great number of straightforward and challenging exercises and problems. It is addressed to students in physics, electrical engineering, and applied mathematics seeking a thorough introduction to electromagnetism with emphasis on radiation theory and its applications.

  6. The generalized Schwinger-DeWitt technique and the unique effective action in quantum gravity

    International Nuclear Information System (INIS)

    Barvinsky, A.O.; Vilkovisky, G.A.

    1983-01-01

    We consider the one-loop approximation to the recently proposed unique effective action in gauge theory. The Schwinger-DeWitt technique is generalized and applied to the computation of the unique gravitational counterterms. The issue of asymptotic freedom is reexamined. (orig.)

  7. On Some Calculations of Effective Action and Fujikawa Regularized Anomaly in the Chiral Schwinger Model

    OpenAIRE

    Mehrdad, GOSHTASBPOUR; Center for Theoretical Physics and Mathematics, AEOI:Department of Physics, Shahid Beheshti University

    1991-01-01

    Extended D^†+D-DD^† Fujikawa regularization of anomaly and a method of integration of fermions for the chiral Schwinger model are criticized. On the basis of the corrected integration method, a new extended version of D^2 is obtained, resulting in the Jackiw-Rajaraman effective action.

  8. Exact solutions of linearized Schwinger endash Dyson equation of fermion self-energy

    International Nuclear Information System (INIS)

    Zhou, B.

    1997-01-01

    The Schwinger endash Dyson equation of fermion self-energy in the linearization approximation is solved exactly in a theory with gauge and effective four-fermion interactions. Different expressions for the independent solutions, which, respectively, submit to irregular and regular ultraviolet boundary condition are derived and expounded. copyright 1997 American Institute of Physics

  9. Dyson-Schwinger equations: connecting small and large length-scales

    International Nuclear Information System (INIS)

    Roberts, C.

    1999-01-01

    The phenomenological application of Dyson-Schwinger equations to the calculation of meson properties observable at TJNAF is illustrated. Particular emphasis is given to the ability of this framework to unify long-range effects constrained by chiral symmetry with short-range effects prescribed by perturbation theory, and interpolate between them

  10. Integration of Schwinger equation for (φ* φ)d2 theory

    International Nuclear Information System (INIS)

    Rochev, V.E.

    1993-01-01

    A general solution for the Schwinger equation for the generating functional of the complex scalar field theory with (φ * φ) d 2 interaction has been constructed. The method is based on the reduction of the order of this equation using the particular solution

  11. Schwinger variational principle in scattering problems of charged particles on mesic atoms and atoms

    International Nuclear Information System (INIS)

    Belyaev, V.B.; Zubarev, A.L.; Podkopaev, A.P.

    1978-01-01

    The Schwinger variational principle is applied to solve the problems of atomic physics. A separable approximation for a Hamiltonian of a bound subsystem is used. The length of e + H-scattering and the elastic p(dμ)-scattering cross section are calculated in the second Born approximation

  12. Path integral measure and the fermion-boson equivalence in the Schwinger model

    International Nuclear Information System (INIS)

    Maiella, G.

    1980-02-01

    I perform a change of field variables in the Schwinger model using the non-invariance of path integral measure under γ 5 transformations. The known equivalence of the model with a bosonic field theory and the Kogut-Susskind dipole mechanism is then derived. (author)

  13. Schwinger's quantum action principle from Dirac’s formulation through Feynman’s path integrals, the Schwinger-Keldysh method, quantum field theory, to source theory

    CERN Document Server

    Milton, Kimball A

    2015-01-01

    Starting from the earlier notions of stationary action principles, these tutorial notes shows how Schwinger’s Quantum Action Principle descended from Dirac’s formulation, which independently led Feynman to his path-integral formulation of quantum mechanics. Part I brings out in more detail the connection between the two formulations, and applications are discussed. Then, the Keldysh-Schwinger time-cycle method of extracting matrix elements is described. Part II will discuss the variational formulation of quantum electrodynamics and the development of source theory.

  14. The Schwinger Dyson equations and the algebra of constraints of random tensor models at all orders

    International Nuclear Information System (INIS)

    Gurau, Razvan

    2012-01-01

    Random tensor models for a generic complex tensor generalize matrix models in arbitrary dimensions and yield a theory of random geometries. They support a 1/N expansion dominated by graphs of spherical topology. Their Schwinger Dyson equations, generalizing the loop equations of matrix models, translate into constraints satisfied by the partition function. The constraints have been shown, in the large N limit, to close a Lie algebra indexed by colored rooted D-ary trees yielding a first generalization of the Virasoro algebra in arbitrary dimensions. In this paper we complete the Schwinger Dyson equations and the associated algebra at all orders in 1/N. The full algebra of constraints is indexed by D-colored graphs, and the leading order D-ary tree algebra is a Lie subalgebra of the full constraints algebra.

  15. Comparing Erlang Distribution and Schwinger Mechanism on Transverse Momentum Spectra in High Energy Collisions

    Directory of Open Access Journals (Sweden)

    Li-Na Gao

    2016-01-01

    Full Text Available We study the transverse momentum spectra of J/ψ and Υ mesons by using two methods: the two-component Erlang distribution and the two-component Schwinger mechanism. The results obtained by the two methods are compared and found to be in agreement with the experimental data of proton-proton (pp, proton-lead (p-Pb, and lead-lead (Pb-Pb collisions measured by the LHCb and ALICE Collaborations at the large hadron collider (LHC. The related parameters such as the mean transverse momentum contributed by each parton in the first (second component in the two-component Erlang distribution and the string tension between two partons in the first (second component in the two-component Schwinger mechanism are extracted.

  16. The Schwinger variational principle in the quantum-mechanical three-body problem

    International Nuclear Information System (INIS)

    Podkopaev, A.P.; Subarev, A.I.; Wrzecionko, J.

    1978-01-01

    The Schwinger variational principle (SVP) is applied to problems of atomic (e + H scattering), mesoatomic (p(dμ) scattering) and nuclear (pion-deuteron scattering) physics. The convergence of the Schwinger variational iterative method is investigated. It is shown that in some cases there occurs a pathological convergence. It means that the iterative procedure is convergent, but not to the exact solution. The method of strong coupling of channels is reformulated on the basis of SVP. it permits the summation over all closed channels. The obtained equations are applied to the calculations of the low energy scattering parameters of the following processes: e + H → e + H; πd → πd. The dependence on πN scattering lengths and effective radii is investigated. It is shown that the contribution of closed channels to the π - d scattering length is 30 percent

  17. Squares of White Noise, SL(2,C) and Kubo - Martin -Schwinger States

    OpenAIRE

    Prokhorenko, D. V.

    2007-01-01

    We investigate the structure of Kubo - Martin - Schwinger (KMS) states on some extension of the universal enveloping algebra of SL(2,C}. We find that there exists a one-to-one correspondence between the set of all covariant KMS states on this algebra and the set of all probability measures d\\mu on the real half-line, which decrease faster than any inverse polynomial. This problem is connected to the problem of KMS states on square of white noise algebra.

  18. The strong running coupling from an approximate gluon Dyson-Schwinger equation

    International Nuclear Information System (INIS)

    Alkofer, R.; Hauck, A.

    1996-01-01

    Using Mandelstam's approximation to the gluon Dyson-Schwinger equation we calculate the gluon self-energy in a renormalisation group invariant fashion. We obtain a non-perturbative Β function. The scaling behavior near the ultraviolet stable fixed point is in good agreement with perturbative QCD. No further fixed point for positive values of the coupling is found: α S increases without bound in the infrared

  19. Lattice Hamiltonian approach to the massless Schwinger model. Precise extraction of the mass gap

    International Nuclear Information System (INIS)

    Cichy, Krzysztof; Poznan Univ.; Kujawa-Cichy, Agnieszka; Szyniszewski, Marcin; Manchester Univ.

    2012-12-01

    We present results of applying the Hamiltonian approach to the massless Schwinger model. A finite basis is constructed using the strong coupling expansion to a very high order. Using exact diagonalization, the continuum limit can be reliably approached. This allows to reproduce the analytical results for the ground state energy, as well as the vector and scalar mass gaps to an outstanding precision better than 10 -6 %.

  20. Lattice Hamiltonian approach to the massless Schwinger model. Precise extraction of the mass gap

    Energy Technology Data Exchange (ETDEWEB)

    Cichy, Krzysztof [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Poznan Univ. (Poland). Faculty of Physics; Kujawa-Cichy, Agnieszka [Poznan Univ. (Poland). Faculty of Physics; Szyniszewski, Marcin [Poznan Univ. (Poland). Faculty of Physics; Manchester Univ. (United Kingdom). NOWNano DTC

    2012-12-15

    We present results of applying the Hamiltonian approach to the massless Schwinger model. A finite basis is constructed using the strong coupling expansion to a very high order. Using exact diagonalization, the continuum limit can be reliably approached. This allows to reproduce the analytical results for the ground state energy, as well as the vector and scalar mass gaps to an outstanding precision better than 10{sup -6} %.

  1. The temperature dependence of the chiral condensate in the Schwinger model with Matrix Product States

    International Nuclear Information System (INIS)

    Saito, H; Jansen, K.; Cichy, K.; Frankfurt Univ.; Poznan Univ.

    2014-12-01

    We present our recent results for the tensor network (TN) approach to lattice gauge theories. TN methods provide an efficient approximation for quantum many-body states. We employ TN for one dimensional systems, Matrix Product States, to investigate the 1-flavour Schwinger model. In this study, we compute the chiral condensate at finite temperature. From the continuum extrapolation, we obtain the chiral condensate in the high temperature region consistent with the analytical calculation by Sachs and Wipf.

  2. Possibility of experimental detection of the Dirac-Schwinger heavy mass monopoles

    Energy Technology Data Exchange (ETDEWEB)

    Ginzburg, I F [AN SSSR, Novosibirsk. Inst. Matematiki; Panfil, S L [AN SSSR, Novosibirsk. Inst. Avtomatiki i Ehlektrometrii

    1982-12-01

    A possibility of the Dirac-Schwinger point heavy-mass monopoles detection in scattering or production of photons at large angles via the monopole loop, is discussed. The monopoles with masses M < or approximately from 50 to 100 GeV may be found in experiments at PETRA and PEP, and monopoles with masses M < or approximately from 2 to 3 TeV may be discovered in future experiments in colliding photon beams of 50-300 GeV energies.

  3. On a Kubo-Martin-Schwinger state of the Sine-Gordon system

    International Nuclear Information System (INIS)

    Peskov, N.V.

    1986-01-01

    This paper considers the Sine-Gordon equation on a finite interval as a Hamiltonian system. A Gaussian measure is defined on an extension of the phase space. It is shown that the partition funciton Z employed in the statistical mechanics of the solitons is an integral with respect to this measure. An algebra of observables is defined and on it a state is constructed which satisfies the Kubo-Martin-Schwinger condition

  4. Confined solutions of the Thirring model coupled to a Schwinger field

    International Nuclear Information System (INIS)

    Hortacsu, M.

    1976-08-01

    In the study of the confined classical solutions of the bosonized massive Thirring field coupled to a Schwinger field, it is observed that, regardless of their respective magnitudes and signs, the Thirring interaction is dominant over the other one, in determining whether such a solution exists. Confined solutions for the Thirring field are possible if and only if the Thirring coupling is attractive. Solutions are constructed for the Thirring model coupling attractive, repulsive and equal to zero

  5. Schwinger variational principle in the nuclear two-body problem and multichannel theory

    International Nuclear Information System (INIS)

    Zubarev, A.L.; Podkopaev, A.P.

    1978-01-01

    The aim of the investigation is to study the Schwinger variational principle in the nuclear two-body problem and the multichannel theory. An approach is proposed to problems of the potential scattering based on the substitution of the exact potential operator V by the finite rank operator Vsup((n)) with which the dynamic equations are solved exactly. The functionals obtained for observed values coincide with corresponding expressions derived by the Schwinger variational principle with the set of test functions. The determination of the Schwinger variational principle is given. The method is given for finding amplitude of the double-particle scattering with the potential Vsup((n)). The corresponding amplitudes are constructed within the framework of the multichannel potential model. Interpolation formula for determining amplitude, which describes with high accuracy a process of elastic scattering for any energies, is obtained. On the basis of the above method high-energy amplitude may be obtained within the range of small and large scattering angles

  6. Non-Schwinger solution of the two-dimensional massless spinor electrodynamics

    International Nuclear Information System (INIS)

    Mikhov, S.G.

    1981-01-01

    In the present paper a regularization procedure is formulated for the current in the two-dimensional massless spinor electrodynamics that is both gauge and γ 5 -gauge invariant. This gives rise to an operator solution of the model that does not involve a massive photon. The latter solution is studied in some detail, and it is shown that although a charge operator exists, it does not define the electric charge of the spinor field. This can be a manifestation of the charge screening mechanism that is present in the Schwinger model [ru

  7. {theta}-vacua in the light-front quantized Schwinger model

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Prem P. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Fisica]|[Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)

    1996-09-01

    The light-front quantization of the bosonized Schwinger model is discussed in the continuum formulation. The proposal, successfully used earlier for describing the spontaneous symmetry breaking on the light-front, of separating first the scalar field into the dynamical condensate and the fluctuation fields before employing the standard Dirac method works here as well. Some topics on the front form theory are summarized in the Appendices and attention is drawn to the fact that the theory quantized, at x{sup +} seems already to carry information on equal x{sup -} commutators as well. (author). 21 refs.

  8. θ-vacua in the light-front quantized Schwinger model

    International Nuclear Information System (INIS)

    Srivastava, Prem P.

    1996-09-01

    The light-front quantization of the bosonized Schwinger model is discussed in the continuum formulation. The proposal, successfully used earlier for describing the spontaneous symmetry breaking on the light-front, of separating first the scalar field into the dynamical condensate and the fluctuation fields before employing the standard Dirac method works here as well. Some topics on the front form theory are summarized in the Appendices and attention is drawn to the fact that the theory quantized, at x + seems already to carry information on equal x - commutators as well. (author). 21 refs

  9. Density induced phase transitions in the Schwinger model. A study with matrix product states

    Energy Technology Data Exchange (ETDEWEB)

    Banuls, Mari Carmen; Cirac, J. Ignacio; Kuehn, Stefan [Max-Planck-Institut fuer Quantenoptik (MPQ), Garching (Germany); Cichy, Krzysztof [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik; Adam Mickiewicz Univ., Poznan (Poland). Faculty of Physics; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2017-02-15

    We numerically study the zero temperature phase structure of the multiflavor Schwinger model at nonzero chemical potential. Using matrix product states, we reproduce analytical results for the phase structure for two flavors in the massless case and extend the computation to the massive case, where no analytical predictions are available. Our calculations allow us to locate phase transitions in the mass-chemical potential plane with great precision and provide a concrete example of tensor networks overcoming the sign problem in a lattice gauge theory calculation.

  10. Delta and Omega electromagnetic form factors in a Dyson-Schwinger/Bethe-Salpeter approach

    Energy Technology Data Exchange (ETDEWEB)

    Diana Nicmorus, Gernot Eichmann, Reinhard Alkofer

    2010-12-01

    We investigate the electromagnetic form factors of the Delta and the Omega baryons within the Poincare-covariant framework of Dyson-Schwinger and Bethe-Salpeter equations. The three-quark core contributions of the form factors are evaluated by employing a quark-diquark approximation. We use a consistent setup for the quark-gluon dressing, the quark-quark bound-state kernel and the quark-photon interaction. Our predictions for the multipole form factors are compatible with available experimental data and quark-model estimates. The current-quark mass evolution of the static electromagnetic properties agrees with results provided by lattice calculations.

  11. The mass spectrum of the Schwinger model with matrix product states

    Energy Technology Data Exchange (ETDEWEB)

    Banuls, M.C.; Cirac, J.I. [Max-Planck-Institut fuer Quantenoptik (MPQ), Garching (Germany); Cichy, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Poznan Univ. (Poland). Faculty of Physics; Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Cyprus Univ., Nicosia (Cyprus). Dept. of Physics

    2013-07-15

    We show the feasibility of tensor network solutions for lattice gauge theories in Hamiltonian formulation by applying matrix product states algorithms to the Schwinger model with zero and non-vanishing fermion mass. We introduce new techniques to compute excitations in a system with open boundary conditions, and to identify the states corresponding to low momentum and different quantum numbers in the continuum. For the ground state and both the vector and scalar mass gaps in the massive case, the MPS technique attains precisions comparable to the best results available from other techniques.

  12. Lattice Hamiltonian approach to the Schwinger model. Further results from the strong coupling expansion

    International Nuclear Information System (INIS)

    Szyniszewski, Marcin; Manchester Univ.; Cichy, Krzysztof; Poznan Univ.; Kujawa-Cichy, Agnieszka

    2014-10-01

    We employ exact diagonalization with strong coupling expansion to the massless and massive Schwinger model. New results are presented for the ground state energy and scalar mass gap in the massless model, which improve the precision to nearly 10 -9 %. We also investigate the chiral condensate and compare our calculations to previous results available in the literature. Oscillations of the chiral condensate which are present while increasing the expansion order are also studied and are shown to be directly linked to the presence of flux loops in the system.

  13. The IR sector of QCD: lattice versus Schwinger-Dyson equations

    International Nuclear Information System (INIS)

    Binosi, Daniele

    2010-01-01

    Important information about the infrared dynamics of QCD is encoded in the behavior of its (of-shell) Green's functions, most notably the gluon and the ghost propagators. Due to recent improvements in the quality of lattice data and the truncation schemes employed for the Schwinger-Dyson equations we have now reached a point where the interplay between these two non-perturbative tools can be most fruitful. In this talk several of the above points will be reviewed, with particular emphasis on the implications for the ghost sector, the non-perturbative effective charge of QCD, and the Kugo-Ojima function.

  14. Self-consistent assessment of Englert-Schwinger model on atomic properties

    Science.gov (United States)

    Lehtomäki, Jouko; Lopez-Acevedo, Olga

    2017-12-01

    Our manuscript investigates a self-consistent solution of the statistical atom model proposed by Berthold-Georg Englert and Julian Schwinger (the ES model) and benchmarks it against atomic Kohn-Sham and two orbital-free models of the Thomas-Fermi-Dirac (TFD)-λvW family. Results show that the ES model generally offers the same accuracy as the well-known TFD-1/5 vW model; however, the ES model corrects the failure in the Pauli potential near-nucleus region. We also point to the inability of describing low-Z atoms as the foremost concern in improving the present model.

  15. Solving Schwinger-Dyson equations by truncation in zero-dimensional scalar quantum field theory

    International Nuclear Information System (INIS)

    Okopinska, A.

    1991-01-01

    Three sets of Schwinger-Dyson equations, for all Green's functions, for connected Green's functions, and for proper vertices, are considered in scalar quantum field theory. A truncation scheme applied to the three sets gives three different approximation series for Green's functions. For the theory in zero-dimensional space-time the results for respective two-point Green's functions are compared with the exact value calculated numerically. The best convergence of the truncation scheme is obtained for the case of proper vertices

  16. To semi-centenary anniversary of discovering the Schwinger scattering and starting the first works on neutron polarizability

    International Nuclear Information System (INIS)

    Alexandrov, Yu.A.

    2006-01-01

    The theory of neutron Schwinger scattering was proposed and developed by Schwinger in 1948, but despite multiple efforts, the experimental discovery of this phenomenon was made eight years later. Currently, Schwinger scattering should be accounted for in many precise neutron experiments, for example, while studying the electromagnetic interaction of neutrons with nuclei. By means of Schwinger scattering it is possible to measure the degree of polarization of the initial beam even at particle energies of 1 GeV order. The concept of neutron polarizability was introduced as additional natural phenomenon indicating the nucleon space structure after the first Hofstadter's experiments (1953-1954). The neutron polarizability was detected in a small-angle neutron scattering experiment in 1957. However, the serious contradiction between the results obtained in megaelectronvolt and kiloelectronvolt neutron energy ranges was explained only in 2001. It is also shown that existent small-angle neutron experiments at megaelectronvolt energy by heavy nuclei do not confirm the idea of (n+3)-dimensional gravity

  17. On Kubo-Martin-Schwinger states of classical dynamical systems with the infinite-dimensional phase space

    International Nuclear Information System (INIS)

    Arsen'ev, A.A.

    1979-01-01

    Example of a classical dynamical system with the infinite-dimensional phase space, satisfying the analogue of the Kubo-Martin-Schwinger conditions for classical dynamics, is constructed explicitly. Connection between the system constructed and the Fock space dynamics is pointed out

  18. Excitation functions of parameters in Erlang distribution, Schwinger mechanism, and Tsallis statistics in RHIC BES program

    International Nuclear Information System (INIS)

    Gao, Li-Na; Liu, Fu-Hu; Lacey, Roy A.

    2016-01-01

    Experimental results of the transverse-momentum distributions of φ mesons and Ω hyperons produced in gold-gold (Au-Au) collisions with different centrality intervals, measured by the STAR Collaboration at different energies (7.7, 11.5, 19.6, 27, and 39 GeV) in the beam energy scan (BES) program at the relativistic heavy-ion collider (RHIC), are approximately described by the single Erlang distribution and the two-component Schwinger mechanism. Moreover, the STAR experimental transverse-momentum distributions of negatively charged particles, produced in Au-Au collisions at RHIC BES energies, are approximately described by the two-component Erlang distribution and the single Tsallis statistics. The excitation functions of free parameters are obtained from the fit to the experimental data. A weak softest point in the string tension in Ω hyperon spectra is observed at 7.7 GeV. (orig.)

  19. The Schwinger Model on S 1: Hamiltonian Formulation, Vacuum and Anomaly

    Science.gov (United States)

    Stuart, David

    2014-12-01

    We present a Hamiltonian formulation of the Schwinger model with spatial domain taken to be the circle. It is shown that, in Coulomb gauge, the Hamiltonian is a semi-bounded, self-adjoint operator which is invariant under the group of large gauge transformations. There is a nontrivial action of on fermionic Fock space and its vacuum. This action plays a role analogous to that played by the spectral flow in the infinite Dirac sea formalism. The formulation allows (1) a description of the anomaly and its relation to the group action, and (2) an explicit identification of the vacuum. The anomaly in the chiral conservation law appears as a consequence of insisting upon semi-boundedness and gauge invariance of the quantized Hamiltonian.

  20. Dyson-Schwinger equations and N = 4 SYM in Landau gauge

    Energy Technology Data Exchange (ETDEWEB)

    Maas, Axel; Zitz, Stefan [University of Graz, Institute of Physics, NAWI Graz, Graz (Austria)

    2016-03-15

    N = 4 Super Yang-Mills theory is a highly constrained theory, and therefore a valuable tool to test the understanding of less constrained Yang-Mills theories. Our aim is to use it to test our understanding of both the Landau gauge beyond perturbation theory and the truncations of Dyson-Schwinger equations in ordinary Yang-Mills theories. We derive the corresponding equations within the usual one-loop truncation for the propagators after imposing the Landau gauge. We find a conformal solution in this approximation, which surprisingly resembles many aspects of ordinary Yang-Mills theories. We furthermore discuss which role the Gribov-Singer ambiguity in this context could play, should it exist in this theory. (orig.)

  1. Lattice-QCD based Schwinger-Dyson approach for Chiral phase transition

    International Nuclear Information System (INIS)

    Iida, Hideaki; Oka, Makoto; Suganuma, Hideo

    2005-01-01

    Dynamical chiral-symmetry breaking in QCD is studied with the Schwinger-Dyson (SD) formalism based on lattice QCD data, i.e., LQCD-based SD formalism. We extract the SD kernel function K(p 2 ) in an Ansatzindependent manner from the lattice data of the quark propagator in the Landau gauge. As remarkable features, we find infrared vanishing and intermediate enhancement of the SD kernel function K(p 2 ). We apply the LQCD-based SD equation to thermal QCD with the quark chemical potential μ q . We find chiral symmetry restoration at T c ∼100MeV for μ q =0. The real part of the quark mass function decreases as T and μ q . At finite density, there appears the imaginary part of the quark mass function, which would lead to the width broadening of hadrons

  2. Hadronic contribution to the muon g-2: A Dyson-Schwinger perspective

    Science.gov (United States)

    Goecke, T.; Fischer, C. S.; Williams, R.

    2012-04-01

    We summarize our results for hadronic contributions to the anomalous magnetic moment of the muon (aμ), the one from hadronic vacuum-polarization (HVP) and the light-by-light scattering contribution (LBL), obtained from the Dyson-Schwinger equations (DSEs) of QCD. In the case of HVP we find good agreement with model independent determinations from dispersion relations for aμHV P as well as for the Adler function with deviations well below the ten percent level. From this we conclude that the DSE approach should be capable of describing aμLBL with similar accuracy. We also present results for LBL using a resonance expansion of the quark-anti-quark T-matrix. Our preliminary value is aμLBL=(217±91)×10-11.

  3. Multiplicative renormalizability and self-consistent treatments of the Schwinger-Dyson equations

    International Nuclear Information System (INIS)

    Brown, N.; Dorey, N.

    1989-11-01

    Many approximations to the Schwinger-Dyson equations place constraints on the renormalization constants of a theory. The requirement that the solutions to the equations be multiplicatively renormalizable also places constraints on these constants. Demanding that these two sets of constraints be compatible is an important test of the self-consistency of the approximations made. We illustrate this idea by considering the equation for the fermion propagator in massless quenched quantum electrodynamics, (QED), checking the consistency of various approximations. In particular, we show that the much used 'ladder' approximation is self-consistent, provided that the coupling constant is renormalized in a particular way. We also propose another approximation which satisfies this self-consistency test, but requires that the coupling be unrenormalized, as should be the case in the full quenched approximation. This new approximation admits an exact solution, which also satisfies the renormalization group equation for the quenched approximation. (author)

  4. The convergence radius of the chiral expansion in the Dyson-Schwinger approach

    International Nuclear Information System (INIS)

    Meissner, T.

    1994-01-01

    We determine the convergence radius m conv or the expansion in the current quark mass using the Dyson-Schwinger (DS) equation of QCD in the rainbow approximation. Within a Gaussian form for the gluon propagator D μ ν(p) ∼ δμνχ 2 e - Δ /p 2 we find that m conv increases with decreasing width Δ and increasing strength χ 2 . For those values of χ 2 and Δ, which provide the best known description of low energy hadronic phenomena, m conv lies around 2Λ QCD , which is big enough, that the chiral expansion in the strange sector converges. Our analysis also explains the rather low value of m conv ∼ 50...80 MeV in the Nambu-Jona-Lasinio model, which as itself can be regarded as a special case of the rainbow DS models, where the gluon propagator is a constant in momentum space

  5. Phase-space analysis of the Schwinger effect in inhomogeneous electromagnetic fields

    Science.gov (United States)

    Kohlfürst, Christian

    2018-05-01

    Schwinger pair production in spatially and temporally inhomogeneous electric and magnetic fields is studied. The focus is on the particle phase-space distribution within a high-intensity few-cycle pulse. Accurate numerical solutions of a quantum kinetic theory (DHW formalism) are presented in momentum space and, with the aid of coarse-graining techniques, in a mixed spatial-momentum representation. Additionally, signatures of the carrier-envelope phase as well as spin-field interactions are discussed on the basis of a trajectory-based model taking into account instantaneous pair production and relativistic single-particle dynamics. Although our simple semi-classical single-particle model cannot describe every aspect of the particle production process (quantum interferences), essential features such as spin-field interactions are captured.

  6. Phase structure of hot and/or dense QCD with the Schwinger-Dyson equation

    Energy Technology Data Exchange (ETDEWEB)

    Takagi, Satoshi [Nagoya Univ., Nagoya, Aichi (Japan)

    2002-09-01

    We investigate the phase structure of the hot and/or dense QCD using the Schwinger-Dyson equation (SDE) with the improved ladder approximation in the Landau gauge. We solve the coupled SDE for the Majorana masses of the quark and antiquark (separately from the SDE for the Dirac mass) in the finite temperature and/or chemical potential region. The resultant phase structure is rather different from those by other analyses. In addition to this analysis we investigate the phase structure with the different two types of the SDE, in one of which the Majorana mass gap of the antiquark is neglected, while in the other of which the Majorana mass gap of the quark and that of the antiquark are set to be equal. The effect of the Debye mass of the gluon on the phase structure is also investigated. (author)

  7. Berezinskii-Kosterlitz-Thouless transition in lattice Schwinger model with one flavor of Wilson fermion

    Science.gov (United States)

    Shimizu, Yuya; Kuramashi, Yoshinobu

    2018-02-01

    We have made a detailed study of the phase structure for the lattice Schwinger model with one flavor of Wilson fermion on the (m ,g ) plane. For numerical investigation, we develop a decorated tensor renormalization method for lattice gauge theories with fermions incorporating the Grassmann tensor renormalization. Our algorithm manifestly preserves rotation and reflection symmetries. We find not only a parity-broken phase but also a Berezinskii-Kosterlitz-Thouless (BKT) transition by evaluating the central charge and an expectation value of a projection operator into the parity-odd subspace. The BKT phase boundaries converge into the degenerated doubler pole (m ,g )=(-2 ,0 ), while the parity-breaking transition line ends at the physical pole (m ,g )=(0 ,0 ). In addition, our analysis of scaling dimensions indicates that a conformal field theory with SU(2) symmetry arises on the line of m =-2 .

  8. Gauge-independent bifurcation to the chiral-symmetry-breaking solution of the Dyson-Schwinger equation in continuum QED

    International Nuclear Information System (INIS)

    Rembiesa, P.

    1990-01-01

    The Dyson-Schwinger equation for the fermion propagator can be effectively solved in the approximation of the small-momentum-transfer vertex function. There exists a critical value of the coupling constant above which the ordinary infrared-divergent solution for massless quantum electrodynamics bifurcates to another, massive solution. With a proper transverse part included in the vertex function, the bifurcation point is gauge independent, the new solution is finite in all gauges, and does not require momentum cutoffs of any kind

  9. Infrared asymptotics and Dyson-Schwinger equations for the gauge-invariant spinor Green function in quantum electrodynamics

    International Nuclear Information System (INIS)

    Skachkov, N.B.; Solovtsov, I.L.; Shevchenko, O.Yu.

    1985-01-01

    The Dayson-Schwinger equations for the gauge-invariant (G.I.) spinor Green function are derived for an Abelian case. On the basis of these equations as well as the functional integration method the behaviour of the G.I. spinor propagator is studied in the infrared region. It is shown that the G.I. propagator has a singularity of a simple pole in this region

  10. Relativistic three-dimensional Lippmann-Schwinger cross sections for space radiation applications

    Science.gov (United States)

    Werneth, C. M.; Xu, X.; Norman, R. B.; Maung, K. M.

    2017-12-01

    Radiation transport codes require accurate nuclear cross sections to compute particle fluences inside shielding materials. The Tripathi semi-empirical reaction cross section, which includes over 60 parameters tuned to nucleon-nucleus (NA) and nucleus-nucleus (AA) data, has been used in many of the world's best-known transport codes. Although this parameterization fits well to reaction cross section data, the predictive capability of any parameterization is questionable when it is used beyond the range of the data to which it was tuned. Using uncertainty analysis, it is shown that a relativistic three-dimensional Lippmann-Schwinger (LS3D) equation model based on Multiple Scattering Theory (MST) that uses 5 parameterizations-3 fundamental parameterizations to nucleon-nucleon (NN) data and 2 nuclear charge density parameterizations-predicts NA and AA reaction cross sections as well as the Tripathi cross section parameterization for reactions in which the kinetic energy of the projectile in the laboratory frame (TLab) is greater than 220 MeV/n. The relativistic LS3D model has the additional advantage of being able to predict highly accurate total and elastic cross sections. Consequently, it is recommended that the relativistic LS3D model be used for space radiation applications in which TLab > 220MeV /n .

  11. Wilsonian Renormalization Group and the Lippmann-Schwinger Equation with a Multitude of Cutoff Parameters

    Science.gov (United States)

    Epelbaum, E.; Gegelia, J.; Meißner, Ulf-G.

    2018-03-01

    The Wilsonian renormalization group approach to the Lippmann-Schwinger equation with a multitude of cutoff parameters is introduced. A system of integro-differential equations for the cutoff-dependent potential is obtained. As an illustration, a perturbative solution of these equations with two cutoff parameters for a simple case of an S-wave low-energy potential in the form of a Taylor series in momenta is obtained. The relevance of the obtained results for the effective field theory approach to nucleon-nucleon scattering is discussed. Supported in part by BMBF under Grant No. 05P2015 - NUSTAR R&D), DFG and NSFC through Funds Provided to the Sino- German CRC 110 “Symmetries and the Emergence of Structure in QCD”, National Natural Science Foundation of China under Grant No. 11621131001, DFG Grant No. TRR110, the Georgian Shota Rustaveli National Science Foundation (grant FR/417/6-100/14) and the CAS President’s International Fellowship Initiative (PIFI) under Grant No. 2017VMA0025

  12. Coupled Dyson-Schwinger equations and effects of self-consistency

    International Nuclear Information System (INIS)

    Wu, S.S.; Zhang, H.X.; Yao, Y.J.

    2001-01-01

    Using the σ-ω model as an effective tool, the effects of self-consistency are studied in some detail. A coupled set of Dyson-Schwinger equations for the renormalized baryon and meson propagators in the σ-ω model is solved self-consistently according to the dressed Hartree-Fock scheme, where the hadron propagators in both the baryon and meson self-energies are required to also satisfy this coupled set of equations. It is found that the self-consistency affects the baryon spectral function noticeably, if only the interaction with σ mesons is considered. However, there is a cancellation between the effects due to the σ and ω mesons and the additional contribution of ω mesons makes the above effect insignificant. In both the σ and σ-ω cases the effects of self-consistency on meson spectral function are perceptible, but they can nevertheless be taken account of without a self-consistent calculation. Our study indicates that to include the meson propagators in the self-consistency requirement is unnecessary and one can stop at an early step of an iteration procedure to obtain a good approximation to the fully self-consistent results of all the hadron propagators in the model, if an appropriate initial input is chosen. Vertex corrections and their effects on ghost poles are also studied

  13. Realization of Massive Relativistic Spin- 3 / 2 Rarita-Schwinger Quasiparticle in Condensed Matter Systems

    Science.gov (United States)

    Tang, Feng; Luo, Xi; Du, Yongping; Yu, Yue; Wan, Xiangang

    Very recently, there has been significant progress in realizing high-energy particles in condensed matter system (CMS) such as the Dirac, Weyl and Majorana fermions. Besides the spin-1/2 particles, the spin-3/2 elementary particle, known as the Rarita-Schwinger (RS) fermion, has not been observed or simulated in the laboratory. The main obstacle of realizing RS fermion in CMS lies in the nontrivial constraints that eliminate the redundant degrees of freedom in its representation of the Poincaré group. In this Letter, we propose a generic method that automatically contains the constraints in the Hamiltonian and prove the RS modes always exist and can be separated from the other non-RS bands. Through symmetry considerations, we show that the two dimensional (2D) massive RS (M-RS) quasiparticle can emerge in several trigonal and hexagonal lattices. Based on ab initio calculations, we predict that the thin film of CaLiX (X=Ge and Si) may host 2D M-RS excitations near the Fermi level. and Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China.

  14. On the Lippmann--Schwinger equation for atom--diatom collisions: A rotating frame treatment

    International Nuclear Information System (INIS)

    Kouri, D.J.; Heil, T.G.; Shimoni, Y.

    1976-01-01

    The use of a rotating frame description of molecular collisions is reconsidered within the framework of the Lippmann--Schwinger equation for the transition or T operator. The present approach explicitly displays the proper boundary conditions which apply to descriptions of such collisions in the rotating frame whose Z axis follows the scattering vector. The resulting body frame equations are shown to lead naturally to the introduction of ''body frame Bessel and Hankel functions,'' J/subJ//subj//sup lambda//sup lambda//sup prime/ and H/subJ//subj//sup lambda//sup lambda//sup prime/ (BFBF), which are solutions of the unperturbed Hamiltonian for the collision transformed to the rotating frame. It is found that the BFBF can be defined in several ways differing by phase factors that affect their asymptotic form. Two particular choices are examined, one of which leads to a simple asymptotic form of the wavefunction, and the other leads to a somewhat more complicated form. Both are shown to yield the j/subz/-conserving coupled states equations of McGuire and Kouri but slightly different approximations are required in the two cases. The implication of these results as to the accuracy of the j/subz/CCS method are discussed

  15. Determination of quantum defects from the poles of the Schwinger T matrix

    International Nuclear Information System (INIS)

    Snitchler, G.L.

    1987-01-01

    Quantum defects are determined for lithium, sodium, potassium, and beryllium by searching for the poles of the Schwinger T matrix along the negative real-energy axis. This method takes advantage of the fundamental ideas of QDT by using a Coulomb Green's function to factor out most of the energy dependence. For the alkali atoms, a single-channel calculation is performed using model potentials to include the effects of core polarization and correlation. Quantum defects accurate to 1% are easily obtained with small grids and small fixed-basis sets for an entire Rydberg series up to principal quantum number, n, as high as 60. A multichannel extension of this method is used to determined neutral-beryllium quantum defects for the 1 P 0 , 3 P 0 , and 3 S Rydberg series. The 1 P 0 and 3 P 0 calculations are performed in a two-channel approximation using 1s 2 2p static-exchange cores. The 3 S calculation includes a third channel with a 1s 2 3s core. Accurate quantum defects are obtained with 4 to 6 basis functions per channel. The energies are variational and the wave functions have the correct asymptotic form enforced by the Coulomb Green's function. Tentative results for Be I 1 P 0 and 3 P 0 resonances below the 1s 2 2p 2 P threshold are presented. This calculation which is performed in a three-channel approximation uses a complex multichannel Coulomb Green's function to search for poles in the fourth quadrant of the complex-energy plane

  16. Extended Hamiltonian formalism of the pure space-like axial gauge Schwinger model. II

    International Nuclear Information System (INIS)

    Nakawaki, Yuji; McCartor, Gary

    2004-01-01

    Canonical methods are not sufficient to properly quantize space-like axial gauges. In this paper, we obtain guiding principles that allow for the construction of an extended Hamiltonian formalism for pure space-like axial gauge fields. To do so, we clarify the general role that residual gauge fields play in the space-like axial gauge Schwinger model. In all the calculations, we fix the gauge using the rule n·A=0, where n is a space-like constant vector, and we refer to its direction as x - . Then, to begin with, we construct a formulation in which the quantization surface is space-like but not parallel to the direction of n. The quantization surface has a parameter that allows us to rotate it, but when we do so, we keep the gauge fixing direction fixed. In that formulation, we can use canonical methods. We bosonize the model to simplify the investigation. We find that the inverse differentiation, (∂ - ) -1 , is ill-defined whatever quantization coordinates we use, as long as the direction of n is space-like. We find that the physical part of the dipole ghost field includes infrared divergences. However, we also find that if we introduce residual gauge fields in such as way that the dipole ghost field satisfies the canonical commutation relations, then the residual gauge fields are determined so as to regularize the infrared divergences contained in the physical part. The propagators then take the form prescribed by Mandelstam and Leibbrandt. We make use of these properties to develop guiding principles that allow us to construct consistent operator solutions in the pure space-like case, in which the quantization surface is parallel to the direction of n, and canonical methods do not suffice. (author)

  17. Phase diagram of two-color QCD in a Dyson-Schwinger approach

    Energy Technology Data Exchange (ETDEWEB)

    Buescher, Pascal Joachim

    2014-04-28

    We investigate two-color QCD with N{sub f}=2 at finite temperatures and chemical potentials using a Dyson-Schwinger approach. We employ two different truncations for the quark loop in the gluon DSE: one based on the Hard-Dense/Hard-Thermal Loop (HDTL) approximation of the quark loop and one based on the back-coupling of the full, self-consistent quark propagator (SCQL). We compare results for the different truncations with each other as well as with other approaches. As expected, we find a phase dominated by the condensation of quark-quark pairs. This diquark condensation phase overshadows the critical end point and first-order phase transition which one finds if diquark condensation is neglected. The phase transition from the phase without diquark condensation to the diquark-condensation phase is of second order. We observe that the dressing with massless quarks in the HDTL approximation leads to a significant violation of the Silver Blaze property and to a too small diquark condensate. The SCQL truncation, on the other hand, is found to reproduce all expected features of the μ-dependent quark condensates. Moreover, with parameters adapted to the situation in other approaches, we also find good to very good agreement with model and lattice calculations in all quark quantities. We find indictions that the physics in recent lattice calculations is likely to be driven solely by the explicit chiral symmetry breaking. Discrepancies w.r.t. the lattice are, however, observed in two quantities that are very sensitive to the screening of the gluon propagator, the dressed gluon propagator itself and the phase-transition line at high temperatures.

  18. Application and development of the Schwinger multichannel scattering theory and the partial differential equation theory of electron-molecule scattering

    Science.gov (United States)

    Weatherford, Charles A.

    1993-01-01

    One version of the multichannel theory for electron-target scattering based on the Schwinger variational principle, the SMC method, requires the introduction of a projection parameter. The role of the projection parameter a is investigated and it is shown that the principal-value operator in the SMC equation is Hermitian regardless of the value of a as long as it is real and nonzero. In a basis that is properly orthonormalizable, the matrix representation of this operator is also Hermitian. The use of such basis is consistent with the Schwinger variational principle because the Lippmann-Schwinger equation automatically builds in the correct boundary conditions. Otherwise, an auxiliary condition needs to be introduced, and Takatsuka and McKoy's original value of a is one of the three possible ways to achieve Hermiticity. In all cases but one, a can be uncoupled from the Hermiticity condition and becomes a free parameter. An equation for a based on the variational stability of the scattering amplitude is derived; its solution has an interesting property that the scattering amplitude from a converged SMC calculation is independent of the choice of a even though the SMC operator itself is a-dependent. This property provides a sensitive test of the convergence of the calculation. For a static-exchange calculation, the convergence requirement only depends on the completeness of the one-electron basis, but for a general multichannel case, the a-invariance in the scattering amplitude requires both the one-electron basis and the N plus 1-electron basis to be complete. The role of a in the SMC equation and the convergence property are illustrated using two examples: e-CO elastic scattering in the static-exchange approximation, and a two-state treatment of the e-H2 Chi(sup 1)Sigma(sub g)(+) yields b(sup 3)Sigma(sub u)(+) excitation.

  19. Prospects of 'Topologically unquenched QCD' from a study of the analogous importance sampling method in the massive Schwinger model

    International Nuclear Information System (INIS)

    Duerr, S.

    2000-01-01

    I give a quick summary of my proposal for simulating an improvement on quenched QCD with dynamical fermions which interact with the gluon configuration only via the topological index of the latter. It amounts to include only the topological part of the functional determinant into the measure, thereby absorbing a correction factor into the observable. I discuss the prospects of this concept from a study in the massive N f- flavour Schwinger model, where the correction factor is indeed found to be of order 0(1)

  20. Low energy elastic scattering of positrons by CO: An application of continued fractions and Schwinger variational iterative methods

    Energy Technology Data Exchange (ETDEWEB)

    Arretche, F. [Departamento de Fisica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, Santa Catarina (Brazil)], E-mail: farretche@hotmail.com; Mazon, K.T.; Michelin, S.E. [Departamento de Fisica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, Santa Catarina (Brazil); Fujimoto, M.M. [Departamento de Fisica, Universidade Federal do Parana, 81531-990, Curitiba, Parana (Brazil); Iga, I.; Lee, M.-T. [Departamento de Quimica, Universidade Federal de Sao Carlos, 13565-905, Sao Paulo (Brazil)

    2008-02-15

    Iterative Schwinger variational methods and the method of continued fractions, widely used for electron-molecule scattering, are applied for the first time to investigate positron-molecule interactions. Specifically, integral and differential cross sections for elastic positron scattering by CO in the (0.5-20) eV energy range are calculated and reported. In our calculation, a static plus correlation-polarization potential is used to represent the collisional dynamics. Our calculated results are in general agreement with the theoretical and experimental data available in the literature.

  1. Existence of Mott-Schwinger interaction proved by means of p-/sup 12/C elastic scattering. [450 to 600 keV

    Energy Technology Data Exchange (ETDEWEB)

    Krause, H H; Arnold, W; Berg, H; Ulbricht, J; Clausnitzer, G [Giessen Univ. (Germany, F.R.). Inst. fuer Kernphysik

    1979-01-01

    The aim of this work was the unambiguous proof of the existence of the Mott-Schwinger interaction. The analyzing power of the p-/sup 12/C elastic scattering was measured in the energy range from 450 to 600 keV for scattering angles theta/sub Lab/ = 90/sup 0/ and 120/sup 0/ with an overall accuracy up to ..delta..A = 1 x /sup -4/. The data can be described very well with the R-matrix formalism including Mott-Schwinger interaction. Omitting this interaction results in large discrepancies.

  2. Jordan-Schwinger map, 3D harmonic oscillator constants of motion, and classical and quantum parameters characterizing electromagnetic wave polarization

    International Nuclear Information System (INIS)

    Mota, R D; Xicotencatl, M A; Granados, V D

    2004-01-01

    In this work we introduce a generalization of the Jauch and Rohrlich quantum Stokes operators when the arrival direction from the source is unknown a priori. We define the generalized Stokes operators as the Jordan-Schwinger map of a triplet of harmonic oscillators with the Gell-Mann and Ne'eman matrices of the SU(3) symmetry group. We show that the elements of the Jordan-Schwinger map are the constants of motion of the three-dimensional isotropic harmonic oscillator. Also, we show that the generalized Stokes operators together with the Gell-Mann and Ne'eman matrices may be used to expand the polarization matrix. By taking the expectation value of the Stokes operators in a three-mode coherent state of the electromagnetic field, we obtain the corresponding generalized classical Stokes parameters. Finally, by means of the constants of motion of the classical 3D isotropic harmonic oscillator we describe the geometrical properties of the polarization ellipse

  3. Jordan Schwinger map, 3D harmonic oscillator constants of motion, and classical and quantum parameters characterizing electromagnetic wave polarization

    Science.gov (United States)

    Mota, R. D.; Xicoténcatl, M. A.; Granados, V. D.

    2004-02-01

    In this work we introduce a generalization of the Jauch and Rohrlich quantum Stokes operators when the arrival direction from the source is unknown a priori. We define the generalized Stokes operators as the Jordan-Schwinger map of a triplet of harmonic oscillators with the Gell-Mann and Ne'eman matrices of the SU(3) symmetry group. We show that the elements of the Jordan-Schwinger map are the constants of motion of the three-dimensional isotropic harmonic oscillator. Also, we show that the generalized Stokes operators together with the Gell-Mann and Ne'eman matrices may be used to expand the polarization matrix. By taking the expectation value of the Stokes operators in a three-mode coherent state of the electromagnetic field, we obtain the corresponding generalized classical Stokes parameters. Finally, by means of the constants of motion of the classical 3D isotropic harmonic oscillator we describe the geometrical properties of the polarization ellipse.

  4. Jordan-Schwinger map, 3D harmonic oscillator constants of motion, and classical and quantum parameters characterizing electromagnetic wave polarization

    Energy Technology Data Exchange (ETDEWEB)

    Mota, R D [Unidad Profesional Interdisciplinaria de IngenierIa y TecnologIas Avanzadas, IPN. Av. Instituto Politecnico Nacional 2580, Col. La Laguna Ticoman, 07340 Mexico DF (Mexico); Xicotencatl, M A [Departamento de Matematicas del Centro de Investigacion y Estudios Avanzados del IPN, Mexico DF, 07000 (Mexico); Granados, V D [Escuela Superior de FIsica y Matematicas, Instituto Politecnico Nacional, Ed. 9, Unidad Profesional Adolfo Lopez Mateos, 07738 Mexico DF (Mexico)

    2004-02-20

    In this work we introduce a generalization of the Jauch and Rohrlich quantum Stokes operators when the arrival direction from the source is unknown a priori. We define the generalized Stokes operators as the Jordan-Schwinger map of a triplet of harmonic oscillators with the Gell-Mann and Ne'eman matrices of the SU(3) symmetry group. We show that the elements of the Jordan-Schwinger map are the constants of motion of the three-dimensional isotropic harmonic oscillator. Also, we show that the generalized Stokes operators together with the Gell-Mann and Ne'eman matrices may be used to expand the polarization matrix. By taking the expectation value of the Stokes operators in a three-mode coherent state of the electromagnetic field, we obtain the corresponding generalized classical Stokes parameters. Finally, by means of the constants of motion of the classical 3D isotropic harmonic oscillator we describe the geometrical properties of the polarization ellipse.

  5. On Schwinger mechanism for gluon pair production in the presence of arbitrary time dependent chromo-electric field

    Energy Technology Data Exchange (ETDEWEB)

    Gavrilov, S.P. [Herzen State Pedagogical University of Russia, Department of General and Experimental Physics, St. Petersburg (Russian Federation); Gitman, D.M. [University of Sao Paulo, Institute of Physics, CP 66318, Sao Paulo, SP (Brazil)

    2009-11-15

    Recently the paper ''Schwinger mechanism for gluon pair production in the presence of arbitrary time dependent chromo-electric field'' by G. C. Nayak was published [Eur. Phys. J. C. 59: 715, 2009; arXiv: 0708.2439]. Its aim is to obtain an exact expression for the probability of non-perturbative gluon pair production per unit time per unit volume and per unit transverse momentum in an arbitrary time-dependent chromo-electric background field. We believe that the obtained expression is open to question. We demonstrate its inconsistency on some well-known examples. We think that this is a consequence of using the so-called ''shift theorem'' [arXiv: hep-th/0609192 ] in deriving the expression for the probability. We make some critical comments on the theorem and its applicability to the problem in question. (orig.)

  6. Two-dimensional massless quantum electrodynamics in the Landau-gauge formalism and the Higgs mechanism. [Schwinger model

    Energy Technology Data Exchange (ETDEWEB)

    Ito, K R [Kyoto Univ. (Japan). Research Inst. for Mathematical Sciences

    1975-03-01

    The Schwinger model is considered in the Landau-gauge formalism of quantum electrodynamics. This model can be solved exactly on the assumption of no radiative corrections to the anomaly. It is found that the photon obtains a non-zero mass through the Higgs mechanism. In this case, the would-be Nambu-Goldstone boson is an associated boson which is constructed from a pair of two-component massless fermions. This would-be Nambu-Goldstone boson appears as a result of the spontaneous breaking of the gauge invariance of the first kind, and it becomes unphysical through the Higgs mechanism. However, as all the fermions themselves decouple from photons, they cannot appear as real particles in our world.

  7. Leading-order calculation of hadronic contributions to the Muon g-2 using the Dyson-Schwinger approach

    Science.gov (United States)

    Goecke, Tobias; Fischer, Christian S.; Williams, Richard

    2011-10-01

    We present a calculation of the hadronic vacuum polarisation (HVP) tensor within the framework of Dyson-Schwinger equations. To this end we use a well-established phenomenological model for the quark-gluon interaction with parameters fixed to reproduce hadronic observables. From the HVP tensor we compute both the Adler function and the HVP contribution to the anomalous magnetic moment of the muon, aμ. We find aμHVP = 6760 ×10-11 which deviates about two percent from the value extracted from experiment. Additionally, we make comparison with a recent lattice determination of aμHVP and find good agreement within our approach. We also discuss the implications of our result for a corresponding calculation of the hadronic light-by-light scattering contribution to aμ.

  8. Leading-order calculation of hadronic contributions to the Muon g-2 using the Dyson-Schwinger approach

    Energy Technology Data Exchange (ETDEWEB)

    Goecke, Tobias [Institut fuer Theoretische Physik, Universitaet Giessen, 35392 Giessen (Germany); Fischer, Christian S., E-mail: christian.fischer@theo.physik.uni-giessen.de [Institut fuer Theoretische Physik, Universitaet Giessen, 35392 Giessen (Germany); Gesellschaft fuer Schwerionenforschung mbH, Planckstr. 1, D-64291 Darmstadt (Germany); Williams, Richard [Dept. Fisica Teorica I, Universidad Complutense, 28040 Madrid (Spain)

    2011-10-13

    We present a calculation of the hadronic vacuum polarisation (HVP) tensor within the framework of Dyson-Schwinger equations. To this end we use a well-established phenomenological model for the quark-gluon interaction with parameters fixed to reproduce hadronic observables. From the HVP tensor we compute both the Adler function and the HVP contribution to the anomalous magnetic moment of the muon, a{sub {mu}}. We find a{sub {mu}}{sup HVP}=6760x10{sup -11} which deviates about two percent from the value extracted from experiment. Additionally, we make comparison with a recent lattice determination of a{sub {mu}}{sup HVP} and find good agreement within our approach. We also discuss the implications of our result for a corresponding calculation of the hadronic light-by-light scattering contribution to a{sub {mu}.}

  9. Leading-order calculation of hadronic contributions to the Muon g-2 using the Dyson-Schwinger approach

    International Nuclear Information System (INIS)

    Goecke, Tobias; Fischer, Christian S.; Williams, Richard

    2011-01-01

    We present a calculation of the hadronic vacuum polarisation (HVP) tensor within the framework of Dyson-Schwinger equations. To this end we use a well-established phenomenological model for the quark-gluon interaction with parameters fixed to reproduce hadronic observables. From the HVP tensor we compute both the Adler function and the HVP contribution to the anomalous magnetic moment of the muon, a μ . We find a μ HVP =6760x10 -11 which deviates about two percent from the value extracted from experiment. Additionally, we make comparison with a recent lattice determination of a μ HVP and find good agreement within our approach. We also discuss the implications of our result for a corresponding calculation of the hadronic light-by-light scattering contribution to a μ .

  10. Schwinger pair production in space- and time-dependent electric fields: Relating the Wigner formalism to quantum kinetic theory

    International Nuclear Information System (INIS)

    Hebenstreit, F.; Alkofer, R.; Gies, H.

    2010-01-01

    The nonperturbative electron-positron pair production (Schwinger effect) is considered for space- and time-dependent electric fields E-vector(x-vector,t). Based on the Dirac-Heisenberg-Wigner formalism, we derive a system of partial differential equations of infinite order for the 16 irreducible components of the Wigner function. In the limit of spatially homogeneous fields the Vlasov equation of quantum kinetic theory is rediscovered. It is shown that the quantum kinetic formalism can be exactly solved in the case of a constant electric field E(t)=E 0 and the Sauter-type electric field E(t)=E 0 sech 2 (t/τ). These analytic solutions translate into corresponding expressions within the Dirac-Heisenberg-Wigner formalism and allow to discuss the effect of higher derivatives. We observe that spatial field variations typically exert a strong influence on the components of the Wigner function for large momenta or for late times.

  11. The multi-flavor Schwinger model with chemical potential. Overcoming the sign problem with matrix product states

    International Nuclear Information System (INIS)

    Banuls, Mari Carmen; Cirac, J. Ignacio; Kuehn, Stefan; Cichy, Krzysztof

    2016-11-01

    During recent years there has been an increasing interest in the application of matrix product states, and more generally tensor networks, to lattice gauge theories. This non-perturbative method is sign problem free and has already been successfully used to compute mass spectra, thermal states and phase diagrams, as well as real-time dynamics for Abelian and non-Abelian gauge models. In previous work we showed the suitability of the method to explore the zero-temperature phase structure of the multi-flavor Schwinger model at non-zero chemical potential, a regime where the conventional Monte Carlo approach suffers from the sign problem. Here we extend our numerical study by looking at the spatially resolved chiral condensate in the massless case. We recover spatial oscillations, similar to the theoretical predictions for the single-flavor case, with a chemical potential dependent frequency and an amplitude approximately given by the homogeneous zero density condensate value.

  12. The multi-flavor Schwinger model with chemical potential. Overcoming the sign problem with matrix product states

    Energy Technology Data Exchange (ETDEWEB)

    Banuls, Mari Carmen; Cirac, J. Ignacio; Kuehn, Stefan [Max-Planck-Institut fuer Quantenoptik (MPQ), Garching (Germany); Cichy, Krzysztof [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik; Adam Mickiewicz Univ., Poznan (Poland). Faculty of Physics; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Saito, Hana [AISIN AW Co., Ltd., Aichi (Japan)

    2016-11-15

    During recent years there has been an increasing interest in the application of matrix product states, and more generally tensor networks, to lattice gauge theories. This non-perturbative method is sign problem free and has already been successfully used to compute mass spectra, thermal states and phase diagrams, as well as real-time dynamics for Abelian and non-Abelian gauge models. In previous work we showed the suitability of the method to explore the zero-temperature phase structure of the multi-flavor Schwinger model at non-zero chemical potential, a regime where the conventional Monte Carlo approach suffers from the sign problem. Here we extend our numerical study by looking at the spatially resolved chiral condensate in the massless case. We recover spatial oscillations, similar to the theoretical predictions for the single-flavor case, with a chemical potential dependent frequency and an amplitude approximately given by the homogeneous zero density condensate value.

  13. Quantum statistical field theory an introduction to Schwinger's variational method with Green's function nanoapplications, graphene and superconductivity

    CERN Document Server

    Morgenstern Horing, Norman J

    2017-01-01

    This book provides an introduction to the methods of coupled quantum statistical field theory and Green's functions. The methods of coupled quantum field theory have played a major role in the extensive development of nonrelativistic quantum many-particle theory and condensed matter physics. This introduction to the subject is intended to facilitate delivery of the material in an easily digestible form to advanced undergraduate physics majors at a relatively early stage of their scientific development. The main mechanism to accomplish this is the early introduction of variational calculus and the Schwinger Action Principle, accompanied by Green's functions. Important achievements of the theory in condensed matter and quantum statistical physics are reviewed in detail to help develop research capability. These include the derivation of coupled field Green's function equations-of-motion for a model electron-hole-phonon system, extensive discussions of retarded, thermodynamic and nonequilibrium Green's functions...

  14. Equilibrium and nonequilibrium many-body perturbation theory: a unified framework based on the Martin-Schwinger hierarchy

    International Nuclear Information System (INIS)

    Van Leeuwen, Robert; Stefanucci, Gianluca

    2013-01-01

    We present a unified framework for equilibrium and nonequilibrium many-body perturbation theory. The most general nonequilibrium many-body theory valid for general initial states is based on a time-contour originally introduced by Konstantinov and Perel'. The various other well-known formalisms of Keldysh, Matsubara and the zero-temperature formalism are then derived as special cases that arise under different assumptions. We further present a single simple proof of Wick's theorem that is at the same time valid in all these flavors of many-body theory. It arises simply as a solution of the equations of the Martin-Schwinger hierarchy for the noninteracting many-particle Green's function with appropriate boundary conditions. We further discuss a generalized Wick theorem for general initial states on the Keldysh contour and derive how the formalisms based on the Keldysh and Konstantinov-Perel'-contours are related for the case of general initial states.

  15. Dryson equations, Ward identities, and the infrared behavior of Yang-Mills theories. [Schwinger-Dyson equations, Slavnov-Taylor identities

    Energy Technology Data Exchange (ETDEWEB)

    Baker, M.

    1979-01-01

    It was shown using the Schwinger-Dyson equations and the Slavnov-Taylor identities of Yang-Mills theory that no inconsistency arises if the gluon propagator behaves like (1/p/sup 2/)/sup 2/ for small p/sup 2/. To see whether the theory actually contains such singular long range behavior, a nonperturbative closed set of equations was formulated by neglecting the transverse parts of GAMMA and GAMMA/sub 4/ in the Schwinger-Dyson equations. This simplification preserves all the symmetries of the theory and allows the possibility for a singular low-momentum behavior of the gluon propagator. The justification for neglecting GAMMA/sup (T)/ and GAMMA/sub 4//sup (T)/ is not evident but it is expected that the present study of the resulting equations will elucidate this simplification, which leads to a closed set of equations.

  16. Schwinger-Dyson loop equations as the w1+∞-like constraints for hermitian multi-matrix chain model at finite N

    International Nuclear Information System (INIS)

    Cheng, Yi-Xin

    1992-01-01

    The Schwinger-Dyson loop equations for the hermitian multi-matrix chain models at finite N, are derived from the Ward identities of the partition functional under the infinitesimal field transformations. The constraint operators W n (m) satisfy the w 1+∞ -like algebra up to a linear combination of the lower spin operators. We find that the all the higher spin constraints are reducible to the Virasoro-type constraints for all the matrix chain models. (author)

  17. Annihilation probability density and other applications of the Schwinger multichannel method to the positron and electron scattering

    International Nuclear Information System (INIS)

    Varella, Marcio Teixeira do Nascimento

    2001-12-01

    We have calculated annihilation probability densities (APD) for positron collisions against He atom and H 2 molecule. It was found that direct annihilation prevails at low energies, while annihilation following virtual positronium (Ps) formation is the dominant mechanism at higher energies. In room-temperature collisions (10 -2 eV) the APD spread over a considerable extension, being quite similar to the electronic densities of the targets. The capture of the positron in an electronic Feshbach resonance strongly enhanced the annihilation rate in e + -H 2 collisions. We also discuss strategies to improve the calculation of the annihilation parameter (Z eff ), after debugging the computational codes of the Schwinger Multichannel Method (SMC). Finally, we consider the inclusion of the Ps formation channel in the SMC and show that effective configurations (pseudo eigenstates of the Hamiltonian of the collision ) are able to significantly reduce the computational effort in positron scattering calculations. Cross sections for electron scattering by polyatomic molecules were obtained in three different approximations: static-exchange (SE); tatic-exchange-plus-polarization (SEP); and multichannel coupling. The calculations for polar targets were improved through the rotational resolution of scattering amplitudes in which the SMC was combined with the first Born approximation (FBA). In general, elastic cross sections (SE and SEP approximations) showed good agreement with available experimental data for several targets. Multichannel calculations for e - -H 2 O scattering, on the other hand, presented spurious structures at the electronic excitation thresholds (author)

  18. Renormalization of self-consistent Schwinger-Dyson equations at finite temperature

    International Nuclear Information System (INIS)

    Hees, H. van; Knoll, J.

    2002-01-01

    We show that Dyson resummation schemes based on Baym's Φ-derivable approximations can be renormalized with counter term structures solely defined on the vacuum level. First applications to the self-consistent solution of the sunset self-energy in φ 4 -theory are presented. (orig.)

  19. Annihilation probability density and other applications of the Schwinger multichannel method to the positron and electron scattering; Densidade de probabilidade de aniquilacao e outras aplicacoes do metodo multicanal de Schwinger ao espalhamento de positrons e eletrons

    Energy Technology Data Exchange (ETDEWEB)

    Varella, Marcio Teixeira do Nascimento

    2001-12-15

    We have calculated annihilation probability densities (APD) for positron collisions against He atom and H{sub 2} molecule. It was found that direct annihilation prevails at low energies, while annihilation following virtual positronium (Ps) formation is the dominant mechanism at higher energies. In room-temperature collisions (10{sup -2} eV) the APD spread over a considerable extension, being quite similar to the electronic densities of the targets. The capture of the positron in an electronic Feshbach resonance strongly enhanced the annihilation rate in e{sup +}-H{sub 2} collisions. We also discuss strategies to improve the calculation of the annihilation parameter (Z{sub eff} ), after debugging the computational codes of the Schwinger Multichannel Method (SMC). Finally, we consider the inclusion of the Ps formation channel in the SMC and show that effective configurations (pseudo eigenstates of the Hamiltonian of the collision ) are able to significantly reduce the computational effort in positron scattering calculations. Cross sections for electron scattering by polyatomic molecules were obtained in three different approximations: static-exchange (SE); tatic-exchange-plus-polarization (SEP); and multichannel coupling. The calculations for polar targets were improved through the rotational resolution of scattering amplitudes in which the SMC was combined with the first Born approximation (FBA). In general, elastic cross sections (SE and SEP approximations) showed good agreement with available experimental data for several targets. Multichannel calculations for e{sup -} -H{sub 2}O scattering, on the other hand, presented spurious structures at the electronic excitation thresholds (author)

  20. How to use the cosmological Schwinger principle for energy flux, entropy, and 'atoms of space-time' to create a thermodynamic space-time and multiverse

    International Nuclear Information System (INIS)

    Beckwith, Andrew

    2011-01-01

    We make explicit an idea by Padmanabhan in DICE 2010, as to finding 'atoms of space-time' permitting a thermodynamic treatment of emergent structure similar to Gibbs treatment of statistical physics. That is, an ensemble of gravitons is used to give an 'atom' of space-time congruent with relic GW. The idea is to reduce the number of independent variables to get a simple emergent space-time structure of entropy. An electric field, based upon the cosmological Schwinger principle, is linked to relic heat flux, with entropy production tied in with candidates as to inflaton potentials. The effective electric field links with the Schwinger 1951s result of an E field leading to pairs of e + e - charges nucleated in space-time volume V · t. Note that in most inflationary models, the assumption is for a magnetic field, not an electric field. An electric field permits a kink-anti-kink construction of an emergent structure, which includes Glinka's recent pioneering approach to a Multiverse. Also an E field allows for an emergent relic particle frequency range between one and 100 GHz. The novel contribution is a relic E field, instead of a B field, in relic space-time 'atom' formation and vacuum nucleation of the same.

  1. Running coupling constant of a gauge theory in the framework of the Schwinger-Dyson equation: Infrared behavior of three-dimensional quantum electrodynamics

    International Nuclear Information System (INIS)

    Kondo, K.

    1997-01-01

    We discuss how to define and obtain the running coupling of a gauge theory in the approach of the Schwinger-Dyson (SD) equation, in order to perform a nonperturbative study of the theory. For this purpose, we introduce the nonlocally generalized gauge fixing into the SD equation, which is used to define the running coupling constant (this method is applicable only to a gauge theory). Some advantages and the validity of this approach are exemplified in QED 3 . This confirms the slowing down of the rate of decrease of the running coupling and the existence of the nontrivial infrared fixed point (in the normal phase) of QED 3 , claimed recently by Aitchison and Mavromatos, without so many of their approximations. We also argue that the conventional approach is recovered by applying the (inverse) Landau-Khalatnikov transformation to the nonlocal gauge result. copyright 1997 The American Physical Society

  2. Playing with Quantum Toys: Julian Schwinger's Measurement Algebra and the Material Culture of Quantum Mechanics Pedagogy at Harvard in the 1960s

    Science.gov (United States)

    Gauvin, Jean-François

    2018-03-01

    In the early 1960s, a PhD student in physics, Costas Papaliolios, designed a simple—and playful—system of Polaroid polarizer filters with a specific goal in mind: explaining the core principles behind Julian Schwinger's quantum mechanical measurement algebra, developed at Harvard in the late 1940s and based on the Stern-Gerlach experiment confirming the quantization of electron spin. Papaliolios dubbed his invention "quantum toys." This article looks at the origins and function of this amusing pedagogical device, which landed half a century later in the Collection of Historical Scientific Instruments at Harvard University. Rendering the abstract tangible was one of Papaliolios's demonstration tactics in reforming basic teaching of quantum mechanics. This article contends that Papaliolios's motivation in creating the quantum toys came from a renowned endeavor aimed, inter alia, at reforming high-school physics training in the United States: Harvard Project Physics. The pedagogical study of these quantum toys, finally, compels us to revisit the central role playful discovery performs in pedagogy, at all levels of training and in all fields of knowledge.

  3. Universality in the relaxation dynamics of the composed black-hole-charged-massive-scalar-field system: The role of quantum Schwinger discharge

    Directory of Open Access Journals (Sweden)

    Shahar Hod

    2015-07-01

    Full Text Available The quasinormal resonance spectrum {ωn(μ,q,M,Q}n=0n=∞ of charged massive scalar fields in the charged Reissner–Nordström black-hole spacetime is studied analytically in the large-coupling regime qQ≫Mμ (here {μ,q} are respectively the mass and charge coupling constant of the field, and {M,Q} are respectively the mass and electric charge of the black hole. This physical system provides a striking illustration for the validity of the universal relaxation bound τ×T≥ħ/π in black-hole physics (here τ≡1/ℑω0 is the characteristic relaxation time of the composed black-hole-scalar-field system, and T is the Bekenstein–Hawking temperature of the black hole. In particular, it is shown that the relaxation dynamics of charged massive scalar fields in the charged Reissner–Nordström black-hole spacetime may saturate this quantum time-times-temperature inequality. Interestingly, we prove that potential violations of the bound by light scalar fields are excluded by the Schwinger-type pair-production mechanism (a vacuum polarization effect, a quantum phenomenon which restricts the physical parameters of the composed black-hole-charged-field system to the regime qQ≪M2μ2/ħ.

  4. How to use the cosmological Schwinger principle for energy flux, entropy, and 'atoms of space-time' to create a thermodynamic space-time and multiverse

    Energy Technology Data Exchange (ETDEWEB)

    Beckwith, Andrew, E-mail: beckwith@iibep.org [71 Lakewood court, apt 7, Moriches, New York, 11955 (United States)

    2011-07-08

    We make explicit an idea by Padmanabhan in DICE 2010, as to finding 'atoms of space-time' permitting a thermodynamic treatment of emergent structure similar to Gibbs treatment of statistical physics. That is, an ensemble of gravitons is used to give an 'atom' of space-time congruent with relic GW. The idea is to reduce the number of independent variables to get a simple emergent space-time structure of entropy. An electric field, based upon the cosmological Schwinger principle, is linked to relic heat flux, with entropy production tied in with candidates as to inflaton potentials. The effective electric field links with the Schwinger 1951s result of an E field leading to pairs of e{sup +}e{sup -} charges nucleated in space-time volume V {center_dot} t. Note that in most inflationary models, the assumption is for a magnetic field, not an electric field. An electric field permits a kink-anti-kink construction of an emergent structure, which includes Glinka's recent pioneering approach to a Multiverse. Also an E field allows for an emergent relic particle frequency range between one and 100 GHz. The novel contribution is a relic E field, instead of a B field, in relic space-time 'atom' formation and vacuum nucleation of the same.

  5. Dictionary of machine terms

    International Nuclear Information System (INIS)

    1990-06-01

    This book has introduction of dictionary of machine terms, and a compilation committee and introductory remarks. It gives descriptions of the machine terms in alphabetical order from a to Z and also includes abbreviation of machine terms and symbol table, way to read mathematical symbols and abbreviation and terms of drawings.

  6. The covariant consistent quantization of bosonized chiral Schwinger model

    International Nuclear Information System (INIS)

    Myung, Y.S.

    1988-01-01

    From Ward-Takahashi identifies and full propagators, the authors obtain a massive Proca field U/sub μ/ which has the positive norm state. There also exists a massless physical scalar field H which turns out to be the positive norm state only for 4e/sup 2/ > 1. It is further shown that a dipole ghost field D and auxiliary field B, as quartet members, belong to the zero norm states

  7. An Etude in non-linear Dyson-Schwinger Equations

    International Nuclear Information System (INIS)

    Kreimer, Dirk; Yeats, Karen

    2006-01-01

    We show how to use the Hopf algebra structure of quantum field theory to derive nonperturbative results for the short-distance singular sector of a renormalizable quantum field theory in a simple but generic example. We discuss renormalized Green functions G R (α,L) in such circumstances which depend on a single scale L=lnq 2 /μ 2 and start from an expansion in the scale G R (α,L)=1+-bar k γ k (α)L k . We derive recursion relations between the γ k which make full use of the renormalization group. We then show how to determine the Green function by the use of a Mellin transform on suitable integral kernels. We exhibit our approach in an example for which we find a functional equation relating weak and strong coupling expansions

  8. What is the trouble with Dyson-Schwinger equations?

    International Nuclear Information System (INIS)

    Kreimer, D.

    2004-01-01

    We discuss similarities and differences between Green Functions in Quantum Field Theory and polylogarithms. Both can be obtained as solutions of fixpoint equations which originate from an underlying Hopf algebra structure. Typically, the equation is linear for the polylog, and non-linear for Green Functions. We argue though that the crucial difference lies not in the non-linearity of the latter, but in the appearance of non-trivial representation theory related to transcendental extensions of the number field which governs the linear solution. An example is studied to illuminate this point

  9. Schwinger-type parametrization of open string worldsheets

    Directory of Open Access Journals (Sweden)

    Sam Playle

    2017-03-01

    Full Text Available A parametrization of (super moduli space near the corners corresponding to bosonic or Neveu–Schwarz open string degenerations is introduced for worldsheets of arbitrary topology. With this parametrization, Feynman graph polynomials arise as the α′→0 limit of objects on moduli space. Furthermore, the integration measures of string theory take on a very simple and elegant form.

  10. The quark Schwinger-Dyson equation in temporal Euclidean space

    Czech Academy of Sciences Publication Activity Database

    Šauli, Vladimír; Batiz, Z.

    2009-01-01

    Roč. 36, č. 3 (2009), 035002/1-035002/13 ISSN 0954-3899 Institutional research plan: CEZ:AV0Z10480505 Keywords : ANALYTIC PERTURBATION-THEORY * DYNAMICAL SYMMETRY-BREAKING * BACKGROUND FIELD METHOD Subject RIV: BE - Theoretical Physics Impact factor: 2.124, year: 2009

  11. Short-distance Schwinger-mechanism and chiral symmetry

    DEFF Research Database (Denmark)

    McGady, David A.; Brogård, Jon

    2017-01-01

    rates depend only on the ratio between the capacitor plate separation, $\\ell$, and the length-scale of the force-field, $\\ell_F$. Chirality ensures that fermion production smoothly vanishes with $\\ell/\\ell_F$. Scalar pair production though diverges exponentially quickly in this limit. The same limit...... of the smooth tanh-potential does not diverge; divergences seem tied to singularities in current and charge densities....

  12. Fermionic Schwinger-Keldysh propagators from AdS/CFT

    International Nuclear Information System (INIS)

    Giecold, G.C.

    2009-01-01

    The Herzog and Son prescription for computing real-time Green functions for finite temperature gauge theories from their gravity dual is generalized to fermions. These notes explain how such an extension involves properties of spinors in a curved, complexified space-time.

  13. 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.)

  14. Glossary of atomic terms

    International Nuclear Information System (INIS)

    1982-04-01

    This glossary, containing almost 400 terms, has been compiled to help people outside the atomic energy industry to understand what those inside it are saying. It is not intended to be a definitive dictionary of scientific or technical terms, nor does it aim to cover terms that are in general use in science and technology. A list of about 100 initials and acronyms will be found at the end. (author)

  15. Glossary of atomic terms

    International Nuclear Information System (INIS)

    1980-01-01

    This glossary (of about 400 terms) has been compiled to help people outside the atomic energy industry to understand what those inside it are saying. It is not intended to be a definitive dictionary of scientific or technical terms, nor does it aim to cover terms that are in general use in science and technology. A list of some initials and acronyms is appended. (author)

  16. Machine terms dictionary

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1979-04-15

    This book gives descriptions of machine terms which includes machine design, drawing, the method of machine, machine tools, machine materials, automobile, measuring and controlling, electricity, basic of electron, information technology, quality assurance, Auto CAD and FA terms and important formula of mechanical engineering.

  17. RxTerms

    Data.gov (United States)

    U.S. Department of Health & Human Services — RxTerms is a drug interface terminology derived from RxNorm for prescription writing or medication history recording (e.g. in e-prescribing systems, PHRs). RxTerms...

  18. (AGA) Pre Term Babies

    African Journals Online (AJOL)

    Haematological Indices in Healthy Appropriate For-Gestational-Age (AGA) Pre Term Babies. ... International Journal of Medicine and Health Development. Journal Home ... Patient and Methods: All consecutive healthy pre-term new born babies delivered at UNTH and admitted into the hospital NBSCU were included.

  19. Toyotarity. Term, model, range

    Directory of Open Access Journals (Sweden)

    Stanisław Borkowski

    2013-04-01

    Full Text Available The Toyotarity and BOST term was presented in the chapter. The BOST method allows to define relations between material resources and human resources and between human resources and human resources (TOYOTARITY. This term was also invented by the Author (and is legally protected. The idea of methodology is an outcome of 12 years of work.

  20. Dictionary of Marketing Terms.

    Science.gov (United States)

    Everhardt, Richard M.

    A listing of words and definitions compiled from more than 10 college and high school textbooks are presented in this dictionary of marketing terms. Over 1,200 entries of terms used in retailing, wholesaling, economics, and investments are included. This dictionary was designed to aid both instructors and students to better understand the…

  1. Dynamic term structure models

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Meldrum, Andrew

    This paper studies whether dynamic term structure models for US nominal bond yields should enforce the zero lower bound by a quadratic policy rate or a shadow rate specification. We address the question by estimating quadratic term structure models (QTSMs) and shadow rate models with at most four...

  2. Long-term collections

    CERN Multimedia

    Collectes à long terme

    2007-01-01

    The Committee of the Long Term Collections (CLT) asks for your attention for the following message from a young Peruvian scientist, following the earthquake which devastated part of her country a month ago.

  3. Glossary of Dental Terms

    Science.gov (United States)

    ... more... Coffee and Doughnuts: A Disastrous Combo for Teeth? The sugars in doughnuts have been identified as ... More print this article enlarge text Glossary of Dental Terms Oral Health Defined Amalgam silver/mercury alloy ...

  4. Nonprice terms and conditions

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    In this and the following chapter the authors review some of the more common provisions contained in wheeling contracts. Here they discuss nonprice terms and conditions. In the next chapter they look at the manner in which they address the pricing issue. At the outset one should note that there is a relationship between price and nonprice terms and condition. A couple of the provisions discussed here affect the risks incurred by the wheeling utility and the price it may charge for that service. These provisions include the length of the contract, the degree to which service can be interrupted and the ability to terminate the contract early, among others. These provisions are often characterized as nonprice terms and conditions. In reality, however, these factors have a direct bearing on the overall cost of wheeling services provided

  5. Measurement of Driving Terms

    CERN Document Server

    Schmidt, F; Faus-Golfe, A

    2001-01-01

    In 2000 a series of MDs has been performed at the SPS to measure resonance driving terms. Theory predicts that these terms can be determined by harmonic analysis of BPM data recorded after applying single kicks at various amplitudes. Strong sextupoles were introduced to create a sizeable amount of nonlinearities. Experiments at injection energy (26 GeV) with single bunch as well as one experiment at 120 GeV with 84 bunches were carried out. The expected nonlinear content is compared to the experimenteal observation.

  6. Long-Term Collections

    CERN Multimedia

    Comité des collectes à long terme

    2011-01-01

    It is the time of the year when our fireman colleagues go around the laboratory for their traditional calendars sale. A part of the money of the sales will be donated in favour of the long-term collections. We hope that you will welcome them warmly.

  7. Nuclear energy terms

    Energy Technology Data Exchange (ETDEWEB)

    1976-01-01

    This is an English-Afrikaans / Afrikaans-English dictionary compiled by the Technical Language Committee of the Atomic Energy Board in collaboration with the Vaktaalburo of the Suid-Afrikaanse Akademie vir Wetenskap en Kuns containing 8515 terms on nuclear energy.

  8. Nuclear energy terms

    International Nuclear Information System (INIS)

    1976-01-01

    This is an English-Afrikaans / Afrikaans-English dictionary compiled by the Technical Language Committee of the Atomic Energy Board in collaboration with the Vaktaalburo of the Suid-Afrikaanse Akademie vir Wetenskap en Kuns containing 8515 terms on nuclear energy

  9. Meaningless terms in rewriting

    NARCIS (Netherlands)

    Kennaway, R.; Oostrom, V. van; Vries, F.-J. de

    We present an axiomatic approach to the concept of meaninglessness in finite and transfinite term rewriting and lambda calculus. We justify our axioms in several ways. They can be intuitively justified from the viewpoint of rewriting as computation. They are shown to imply important properties

  10. Short-term memory

    Science.gov (United States)

    Toulouse, G.

    This is a rather bold attempt to bridge the gap between neuron structure and psychological data. We try to answer the question: Is there a relation between the neuronal connectivity in the human cortex (around 5,000) and the short-term memory capacity (7±2)? Our starting point is the Hopfield model (Hopfield 1982), presented in this volume by D.J. Amit.

  11. Half term report

    CERN Multimedia

    2011-01-01

    This week marks the mid-point of my mandate as Director General, so what better time to take stock of the last two and a half years and look forward to the next?    On the surface, the report is good. The LHC is performing well, Council has just approved our medium term plan, and the there seem to be few clouds on CERN’s long-term horizon. It’s precisely at times like this, however, that complacency would be most dangerous. The world is still in the grip of an economic crisis, and recovery in our Member States is slow. CERN is still in debt, as are our social security systems. We are working on this, but these factors need constant and careful attention. While we need to remain vigilant, I’d like to focus on the positives for my mid term message. Let’s start with the LHC. The machine’s performance this year has been fantastic. We achieved our target luminosity for the year in June, which augurs well for the summer conferences. I don&r...

  12. Pediatric polytrauma : Short-term and long-term outcomes

    NARCIS (Netherlands)

    vanderSluis, CK; Kingma, J; Eisma, WH; tenDuis, HJ

    Objective: To assess the short-term and long-term outcomes of pediatric polytrauma patients and to analyze the extent to which short-term outcomes can predict long-term outcomes. Materials and Methods: Ail pediatric polytrauma patients (Injury Severity Score of greater than or equal to 16, less than

  13. Chernobyl source term estimation

    International Nuclear Information System (INIS)

    Gudiksen, P.H.; Harvey, T.F.; Lange, R.

    1990-09-01

    The Chernobyl source term available for long-range transport was estimated by integration of radiological measurements with atmospheric dispersion modeling and by reactor core radionuclide inventory estimation in conjunction with WASH-1400 release fractions associated with specific chemical groups. The model simulations revealed that the radioactive cloud became segmented during the first day, with the lower section heading toward Scandinavia and the upper part heading in a southeasterly direction with subsequent transport across Asia to Japan, the North Pacific, and the west coast of North America. By optimizing the agreement between the observed cloud arrival times and duration of peak concentrations measured over Europe, Japan, Kuwait, and the US with the model predicted concentrations, it was possible to derive source term estimates for those radionuclides measured in airborne radioactivity. This was extended to radionuclides that were largely unmeasured in the environment by performing a reactor core radionuclide inventory analysis to obtain release fractions for the various chemical transport groups. These analyses indicated that essentially all of the noble gases, 60% of the radioiodines, 40% of the radiocesium, 10% of the tellurium and about 1% or less of the more refractory elements were released. These estimates are in excellent agreement with those obtained on the basis of worldwide deposition measurements. The Chernobyl source term was several orders of magnitude greater than those associated with the Windscale and TMI reactor accidents. However, the 137 Cs from the Chernobyl event is about 6% of that released by the US and USSR atmospheric nuclear weapon tests, while the 131 I and 90 Sr released by the Chernobyl accident was only about 0.1% of that released by the weapon tests. 13 refs., 2 figs., 7 tabs

  14. Expected Term Structures

    DEFF Research Database (Denmark)

    Buraschi, Andrea; Piatti, Ilaria; Whelan, Paul

    We construct and study the cross-sectional properties of survey-based bond risk premia and compare them to their traditional statistical counterparts. We document large heterogeneity in skill, identify top forecasters, and learn about the importance of subjective risk premia in long-term bonds...... dynamics. The consensus is not a sufficient statistics of the cross-section of expectations and we propose an alternative real-time aggregate measure of risk premia consistent with Friedmans market selection hypothesis. We then use this measure to evaluate structural models and find support...

  15. Term Structure Persistence

    OpenAIRE

    Abbritti, M. (Mirko); Gil-Alana, L.A. (Luis A.); Lovcha, Y. (Yuliya); Moreno, A. (Antonio)

    2012-01-01

    Stationary I(0) models employed in yield curve analysis typically imply an unrealistically low degree of volatility in long-run short-rate expectations due to fast mean reversion. In this paper we propose a novel multivariate affine term structure model with a two-fold source of persistence in the yield curve: Long-memory and short-memory. Our model, based on an I(d) specification, nests the I(0) and I(1) models as special cases and the I(0) model is decisively rejected by the data. Our model...

  16. Long-Term Collections

    CERN Multimedia

    Staff Association

    2016-01-01

    45 years helping in developing countries! CERN personnel have been helping the least fortunate people on the planet since 1971. How? With the Long-Term Collections! Dear Colleagues, The Staff Association’s Long-Term Collections (LTC) Committee is delighted to share this important milestone in the life of our Laboratory with you. Indeed, whilst the name of CERN is known worldwide for scientific discoveries, it also shines in the many humanitarian projects which have been supported by the LTC since 1971. Several schools and clinics, far and wide, carry its logo... Over the past 45 years, 74 projects have been supported (9 of which are still ongoing). This all came from a group of colleagues who wanted to share a little of what life offered them here at CERN, in this haven of mutual understanding, peace and security, with those who were less fortunate elsewhere. Thus, the LTC were born... Since then, we have worked as a team to maintain the dream of these visionaries, with the help of regular donat...

  17. Long-Term Collection

    CERN Multimedia

    Staff Association

    2016-01-01

    Dear Colleagues, As previously announced in Echo (No. 254), your delegates took action to draw attention to the projects of the Long-Term Collections (LTC), the humanitarian body of the CERN Staff Association. On Tuesday, 11 October, at noon, small Z-Cards were widely distributed at the entrances of CERN restaurants and we thank you all for your interest. We hope to have achieved an important part of our goal, which was to inform you, convince you and find new supporters among you. We will find out in the next few days! An exhibition of the LTC was also set up in the Main Building for the entire week. The Staff Association wants to celebrate the occasion of the Long-Term Collection’s 45th anniversary at CERN because, ever since 1971, CERN personnel have showed great support in helping the least fortunate people on the planet in a variety of ways according to their needs. On a regular basis, joint fundraising appeals are made with the Directorate to help the victims of natural disasters around th...

  18. Collectes à long terme

    CERN Multimedia

    Collectes à long terme

    2014-01-01

    En cette fin d’année 2014 qui approche à grands pas, le Comité des Collectes à Long Terme remercie chaleureusement ses fidèles donatrices et donateurs réguliers pour leurs contributions à nos actions en faveur des plus démunis de notre planète. C’est très important, pour notre Comité, de pouvoir compter sur l’appui assidu que vous nous apportez. Depuis plus de 40 ans maintenant, le modèle des CLT est basé principalement sur des actions à long terme (soit une aide pendant 4-5 ans par projet, mais plus parfois selon les circonstances), et sa planification demande une grande régularité de ses soutiens financiers. Grand MERCI à vous ! D’autres dons nous parviennent au cours de l’année, et ils sont aussi les bienvenus. En particulier, nous tenons à remercier...

  19. Audit of long-term and short-term liabilities

    Directory of Open Access Journals (Sweden)

    Korinko M.D.

    2017-03-01

    Full Text Available The article determines the importance of long-term and short-term liabilities for the management of financial and material resources of an enterprise. It reviews the aim, objects and information generators for realization of audit of short-term and long-term obligations. The organizing and methodical providing of audit of long-term and short-term liabilities of an enterprise are generalized. The authors distinguish the stages of realization of audit of long-term and short-term liabilities, the aim of audit on each of the presented stages, and recommend methodical techniques. It is fixed that it is necessary to conduct the estimation of the systems of internal control and record-keeping of an enterprise by implementation of public accountant procedures for determination of volume and maintenance of selection realization. After estimating the indicated systems, a public accountant determines the methodology for realization of public accountant verification of long-term and short-term liabilities. The analytical procedures that public accountants are expedient to use for realization of audit of short-term and long-term obligations are determined. The authors suggest the classification of the educed defects on the results of the conducted public accountant verification of short-term and long-term obligations.

  20. Diversification: Far term (2000 - )

    Science.gov (United States)

    1975-01-01

    Diversification, intended to underly the far term of the energy conservation program, was defined to imply conservation through substitution for scarce energy resources by maximizing the total number of viable energy system types in every sector. The following requirements or aspects of diversification that must be studied were given: fuel mix and end use patterns for various alternative diversification plans, current status of diversification, advantages and disadvantages of diversification, constraints and criteria, diversification actions and their controls, and means for implementing the chosen diversification strategy. The following advantages resulting from diversification were described: competition, crisis-related situations, local energy production, decentralized plant locations, long range energy policy, and environmental overloads. The major criteria by which a diversification program should be judged, the major constraints affecting the approaches, and the road to diversification, were elaborated.

  1. A study of the path-integral quantization of Abelian gauge theories when no explicit gauge-fixing term is included in the bilinear part of the gauge-field action

    International Nuclear Information System (INIS)

    Phillips, S.

    1985-01-01

    The mathematical problem of inverting the operator Δ x μν ≡ g μν g αβ δ x α δ x β -δ x μ δ x ν , as it arises in the path-integral quantization of an Abelian gauge theory, such as quantum electrodynamics, when no gauge-fixing Lagrangian field density is included, is studied in this article. Making use of the fact that the Schwinger source functions, which are introduced for the purpose of generating Green's functions, are free of divergence, a result that follows from the conversion of the exponentiated action into a Gaussian form, the apparently noninvertible partial differential equation, Δ x μν L ν (x) J μ (x), can, by the addition and subsequent subtraction of terms containing the divergence of the source function, be cast into a form that does possess a Green's function solution. The gauge-field propagator is the same as that obtained by the conventional technique, which involves gauge fixing when the gauge parameter, α, is set equal to one. Such an analysis suggests also that, provided the effect of fictitious particles that propagate only in closed loops are included for the study of Green's functions in non-Abelian gauge theories in Landau-type gauges, then, in quantizing either Abelian gauge theories or non-Abelian gauge theories in this generic kind of gauge, it is not necessary to add an explicit gauge-fixing term to the bilinear part of the gauge-field action

  2. Introduction: Long term prediction

    International Nuclear Information System (INIS)

    Beranger, G.

    2003-01-01

    Making a decision upon the right choice of a material appropriate to a given application should be based on taking into account several parameters as follows: cost, standards, regulations, safety, recycling, chemical properties, supplying, transformation, forming, assembly, mechanical and physical properties as well as the behaviour in practical conditions. Data taken from a private communication (J.H.Davidson) are reproduced presenting the life time range of materials from a couple of minutes to half a million hours corresponding to applications from missile technology up to high-temperature nuclear reactors or steam turbines. In the case of deep storage of nuclear waste the time required is completely different from these values since we have to ensure the integrity of the storage system for several thousand years. The vitrified nuclear wastes should be stored in metallic canisters made of iron and carbon steels, stainless steels, copper and copper alloys, nickel alloys or titanium alloys. Some of these materials are passivating metals, i.e. they develop a thin protective film, 2 or 3 nm thick - the so-called passive films. These films prevent general corrosion of the metal in a large range of chemical condition of the environment. In some specific condition, localized corrosion such as the phenomenon of pitting, occurs. Consequently, it is absolutely necessary to determine these chemical condition and their stability in time to understand the behavior of a given material. In other words the corrosion system is constituted by the complex material/surface/medium. For high level nuclear wastes the main features for resolving problem are concerned with: geological disposal; deep storage in clay; waste metallic canister; backfill mixture (clay-gypsum) or concrete; long term behavior; data needed for modelling and for predicting; choice of appropriate solution among several metallic candidates. The analysis of the complex material/surface/medium is of great importance

  3. Handbook of mechanical engineering terms

    CERN Document Server

    Ramalingam, KK

    2009-01-01

    About the Book: The Handbook of Mechanical Engineering terms contains short, precise definitions of about four thousand terms. These terms have been collected from different sources, edited and grouped under twenty six parts and given alphabetically under each part for easy reference. The book will be a source of guidance and help to the students, staff and practising engineers in understanding and updating the subject matter. Contents: The Handbook of Mechanical Engineering terms contains short, precise definitions of about four thousand terms. These terms have been collected from differ

  4. A profession termed Journalism

    Directory of Open Access Journals (Sweden)

    Manuel Fernández Areal, Ph. D.

    2010-01-01

    Full Text Available New technologies can foster the impression that journalism, as a profession will become extinct probably in a short term. Anybody can have access to any information sources as well as to transmit – through Internet- all sorts of messages at an unusual speed, and this fact seems to support the idea that no technical training will be needed in the future not even an specific cultural background will be required, much less an university degree or qualification that ensures a responsible and appropriate practice of the modern social communication. The Federation of Journalists Associations in Spain (FAPE in its Draft of the Professional Statute is in favor of a graduated or qualified profession at an university level, and its Commission for Complaints has been developing a successful work regarding the professional self-regulation and self-control for the benefit of society. Therefore, there are good reasons for being optimist. Journalism, as a profession, is not going to disappear, and maybe it is time to consider it, really, as an academic qualified profession.

  5. LONG TERM COLLECTIONS

    CERN Multimedia

    STAFF ASSOCIATION

    2010-01-01

    ACKNOWLEDGMENTS The Long-Term Collections (CLT) committee would like to warmly thank its faithful donors who, year after year, support our actions all over the world. Without you, all this would not be possible. We would like to thank, in particular, the CERN Firemen’s Association who donated 5000 CHF in the spring thanks to the sale of their traditional calendar, and the generosity of the CERN community. A huge thank you to the firemen for their devotion to our cause. And thank you to all those who have opened their door, their heart, and their purses! Similarly, we warmly thank the CERN Yoga Club once again for its wonderful donation of 2000 CHF we recently received. We would also like to tell you that all our projects are running well. Just to remind you, we are currently supporting the activities of the «Réflexe-Partage» Association in Mali; the training centre of «Education et Développement» in Abomey, Benin; and the orphanage and ...

  6. Long-Term Symbolic Learning

    National Research Council Canada - National Science Library

    Kennedy, William G; Trafton, J. G

    2007-01-01

    What are the characteristics of long-term learning? We investigated the characteristics of long-term, symbolic learning using the Soar and ACT-R cognitive architectures running cognitive models of two simple tasks...

  7. Evaluating long term forecasts

    Energy Technology Data Exchange (ETDEWEB)

    Lady, George M. [Department of Economics, College of Liberal Arts, Temple University, Philadelphia, PA 19122 (United States)

    2010-03-15

    The U.S. Department of Energy's Energy Information Administration (EIA), and its predecessor organizations, has published projections of U.S. energy production, consumption, distribution and prices annually for over 30 years. A natural issue to raise in evaluating the projections is an assessment of their accuracy compared to eventual outcomes. A related issue is the determination of the sources of 'error' in the projections that are due to differences between the actual versus realized values of the associated assumptions. One way to do this would be to run the computer-based model from which the projections are derived at the time the projected values are realized, using actual rather than assumed values for model assumptions; and, compare these results to the original projections. For long term forecasts, this approach would require that the model's software and hardware configuration be archived and available for many years, possibly decades, into the future. Such archival creates many practical problems; and, in general, it is not being done. This paper reports on an alternative approach for evaluating the projections. In the alternative approach, the model is run many times for cases in which important assumptions are changed individually and in combinations. A database is assembled from the solutions and a regression analysis is conducted for each important projected variable with the associated assumptions chosen as exogenous variables. When actual data are eventually available, the regression results are then used to estimate the sources of the differences in the projections of the endogenous variables compared to their eventual outcomes. The results presented here are for residential and commercial sector natural gas and electricity consumption. (author)

  8. Cooling towers - terms and definitions

    International Nuclear Information System (INIS)

    1991-02-01

    In the field of cooling tower construction and operation, the use of publications has shown that a systematic glossary has not yet been developed. Therefore a dictionary of the terms used in this field, together with their clear definitions, is urgently required. This work has been started by the V.I.K. (Association for the Industrial Power Economy) in Essen and completed by the VDI-Group 'Energy Engineering'. Because of the strong international links and the increasing overseas trade in this field also the corresponding terms in other languages, English, French and Spanish are included. As to make it possible to find the German terms and definitions when starting from a foreign language, alphabetical lists are included for the various languages giving the number of the corresponding German term. In such cases where the technical term used in the United States is not identical with the corresponding term used in the United Kingdom, both terms are included. (orig./HP) [de

  9. Rewriting and suppressing UMLS terms for improved biomedical term identification

    Directory of Open Access Journals (Sweden)

    Hettne Kristina M

    2010-03-01

    Full Text Available Abstract Background Identification of terms is essential for biomedical text mining.. We concentrate here on the use of vocabularies for term identification, specifically the Unified Medical Language System (UMLS. To make the UMLS more suitable for biomedical text mining we implemented and evaluated nine term rewrite and eight term suppression rules. The rules rely on UMLS properties that have been identified in previous work by others, together with an additional set of new properties discovered by our group during our work with the UMLS. Our work complements the earlier work in that we measure the impact on the number of terms identified by the different rules on a MEDLINE corpus. The number of uniquely identified terms and their frequency in MEDLINE were computed before and after applying the rules. The 50 most frequently found terms together with a sample of 100 randomly selected terms were evaluated for every rule. Results Five of the nine rewrite rules were found to generate additional synonyms and spelling variants that correctly corresponded to the meaning of the original terms and seven out of the eight suppression rules were found to suppress only undesired terms. Using the five rewrite rules that passed our evaluation, we were able to identify 1,117,772 new occurrences of 14,784 rewritten terms in MEDLINE. Without the rewriting, we recognized 651,268 terms belonging to 397,414 concepts; with rewriting, we recognized 666,053 terms belonging to 410,823 concepts, which is an increase of 2.8% in the number of terms and an increase of 3.4% in the number of concepts recognized. Using the seven suppression rules, a total of 257,118 undesired terms were suppressed in the UMLS, notably decreasing its size. 7,397 terms were suppressed in the corpus. Conclusions We recommend applying the five rewrite rules and seven suppression rules that passed our evaluation when the UMLS is to be used for biomedical term identification in MEDLINE. A software

  10. Algebraic isomorphism in two-dimensional anomalous gauge theories

    International Nuclear Information System (INIS)

    Carvalhaes, C.G.; Belvedere, L.V.; Filho, H.B.; Natividade, C.P.

    1997-01-01

    The operator solution of the anomalous chiral Schwinger model is discussed on the basis of the general principles of Wightman field theory. Some basic structural properties of the model are analyzed taking a careful control on the Hilbert space associated with the Wightman functions. The isomorphism between gauge noninvariant and gauge invariant descriptions of the anomalous theory is established in terms of the corresponding field algebras. We show that (i) the Θ-vacuum representation and (ii) the suggested equivalence of vector Schwinger model and chiral Schwinger model cannot be established in terms of the intrinsic field algebra. copyright 1997 Academic Press, Inc

  11. Gogny interactions with tensor terms

    Energy Technology Data Exchange (ETDEWEB)

    Anguiano, M.; Lallena, A.M.; Bernard, R.N. [Universidad de Granada, Departamento de Fisica Atomica, Molecular y Nuclear, Granada (Spain); Co' , G. [INFN, Lecce (Italy); De Donno, V. [Universita del Salento, Dipartimento di Matematica e Fisica ' ' E. De Giorgi' ' , Lecce (Italy); Grasso, M. [Universite Paris-Sud, Institut de Physique Nucleaire, IN2P3-CNRS, Orsay (France)

    2016-07-15

    We present a perturbative approach to include tensor terms in the Gogny interaction. We do not change the values of the usual parameterisations, with the only exception of the spin-orbit term, and we add tensor terms whose only free parameters are the strengths of the interactions. We identify observables sensitive to the presence of the tensor force in Hartree-Fock, Hartree-Fock-Bogoliubov and random phase approximation calculations. We show the need of including two tensor contributions, at least: a pure tensor term and a tensor-isospin term. We show results relevant for the inclusion of the tensor term for single-particle energies, charge-conserving magnetic excitations and Gamow-Teller excitations. (orig.)

  12. Long Term Financing of Infrastructure

    OpenAIRE

    Sinha, Sidharth

    2014-01-01

    Infrastructure projects, given their long life, require long term financing. The main sources of long term financings are insurance and pension funds who seek long term investments with low credit risk. However, in India household financial savings are mainly invested in bank deposits. Insurance and pension funds account for only a small percentage of household financial savings. In addition most infrastructure projects do not qualify for investment by insurance and pension funds because of t...

  13. Rewriting and suppressing UMLS terms for improved biomedical term identification

    NARCIS (Netherlands)

    K.M. Hettne (Kristina); E.M. van Mulligen (Erik); M.J. Schuemie (Martijn); R.J.A. Schijvenaars (Bob); J.A. Kors (Jan)

    2010-01-01

    textabstractBackground: Identification of terms is essential for biomedical text mining. We concentrate here on the use of vocabularies for term identification, specifically the Unified Medical Language System (UMLS). To make the UMLS more suitable for biomedical text mining we implemented and

  14. Fission-product source terms

    International Nuclear Information System (INIS)

    Lorenz, R.A.

    1981-01-01

    This presentation consists of a review of fission-product source terms for light water reactor (LWR) fuel. A source term is the quantity of fission products released under specified conditions that can be used to calculate the consequences of the release. The source term usually defines release from breached fuel-rod cladding but could also describe release from the primary coolant system, the reactor containment shell, or the site boundary. The source term would be different for each locality, and the chemical and physical forms of the fission products could also differ

  15. History of Physical Terms: "Energy"

    Science.gov (United States)

    Frontali, Clara

    2014-01-01

    Difficulties encountered by teachers in giving a definition of the term "energy", and by students in grasping its actual meaning, reflect the lengthy process through which the concept eventually came to maturity around 1850. Tracing the history of this process illuminates the different aspects covered by the term and shows the important…

  16. Long-term urethral catheterisation.

    Science.gov (United States)

    Turner, Bruce; Dickens, Nicola

    This article discusses long-term urethral catheterisation, focusing on the relevant anatomy and physiology, indications for the procedure, catheter selection and catheter care. It is important that nurses have a good working knowledge of long-term catheterisation as the need for this intervention will increase with the rise in chronic health conditions and the ageing population.

  17. Nuclear technology terms and definitions

    International Nuclear Information System (INIS)

    1979-02-01

    The terms and definitions in this standard are part of the catalogue of definitions 'Nuclear technology, terms and definitions', in eight parts; they are the latest version of the standards and draft standards of DIN 25 401, part 10 to 19, published at irregular intervals until now. (orig.) [de

  18. Color Terms and Color Concepts

    Science.gov (United States)

    Davidoff, Jules

    2006-01-01

    In their lead articles, both Kowalski and Zimiles (2006) and O'Hanlon and Roberson (2006) declare a general relation between color term knowledge and the ability to conceptually represent color. Kowalski and Zimiles, in particular, argue for a priority for the conceptual representation in color term acquisition. The complexities of the interaction…

  19. The Term Processor Generator Kimwitu

    NARCIS (Netherlands)

    van Eijk, P.H.J.; van Eijk, Peter; Belinfante, Axel; Eertink, E.H.; Eertink, Henk; Alblas, H.; Brinksma, Hendrik

    The Kimwitu system is a meta-tool that supports the construction of programs (tools) that operate on trees or terms. The system supports open multi-paradigm programming, in that it allows to express each part of an implementation in the most appropriate language. Terms can be implemented in a tool

  20. Telecommunications glossary of telecommunications terms

    CERN Document Server

    1997-01-01

    This glossary contains more than 5,000 technical terms and definitions that were standardized by the federal government for use by international and U.S. government telecommunications specialists. It includes international and national terms drawn from the International Telecommunication Union, the International Organization for Standardization, the TIA, ANSI, and others.

  1. Lovelock terms and BRST cohomology

    International Nuclear Information System (INIS)

    Cnockaert, Sandrine; Henneaux, Marc

    2005-01-01

    Lovelock terms are polynomial scalar densities in the Riemann curvature tensor that have the remarkable property that their Euler-Lagrange derivatives contain derivatives of the metric of an order not higher than 2 (while generic polynomial scalar densities lead to Euler-Lagrange derivatives with derivatives of the metric of order 4). A characteristic feature of Lovelock terms is that their first nonvanishing term in the expansion g λμ = η λμ + h λμ of the metric around flat space is a total derivative. In this paper, we investigate generalized Lovelock terms defined as polynomial scalar densities in the Riemann curvature tensor and its covariant derivatives (of arbitrarily high but finite order) such that their first nonvanishing term in the expansion of the metric around flat space is a total derivative. This is done by reformulating the problem as a BRST cohomological one and by using cohomological tools. We determine all the generalized Lovelock terms. We find, in fact, that the class of nontrivial generalized Lovelock terms contains only the usual ones. Allowing covariant derivatives of the Riemann tensor does not lead to a new structure. Our work provides a novel algebraic understanding of the Lovelock terms in the context of BRST cohomology

  2. What Do Mental Terms Mean?

    Science.gov (United States)

    Moore, Jay

    2010-01-01

    Psychologists and philosophers have long been interested in two questions: (a) What do mental terms mean? and (b) what role do mental terms play in explanations of behavior? In the current sketch I review how mediational neobehaviorism, cognitive psychology, and the radical behaviorism of B. F. Skinner address these questions. In so doing, I seek…

  3. The uranium industry: long term planning for short term competition

    International Nuclear Information System (INIS)

    Vottero, X.

    2000-01-01

    Today, uranium producers face new challenges in terms of both production (new regulatory, environmental and social constraints) and market conditions (new sources of uranium supply, very low prices and tough competition). In such a context, long-term planning is not just a prerequisite to survive in the nuclear fuel cycle industry. In fact, it also contributes to sustaining nuclear electricity generation facing fierce competition from other energy sources in increasingly deregulated markets. (authors)

  4. Modulus D-term inflation

    Science.gov (United States)

    Kadota, Kenji; Kobayashi, Tatsuo; Saga, Ikumi; Sumita, Keigo

    2018-04-01

    We propose a new model of single-field D-term inflation in supergravity, where the inflation is driven by a single modulus field which transforms non-linearly under the U(1) gauge symmetry. One of the notable features of our modulus D-term inflation scenario is that the global U(1) remains unbroken in the vacuum and hence our model is not plagued by the cosmic string problem which can exclude most of the conventional D-term inflation models proposed so far due to the CMB observations.

  5. Partial order infinitary term rewriting

    DEFF Research Database (Denmark)

    Bahr, Patrick

    2014-01-01

    We study an alternative model of infinitary term rewriting. Instead of a metric on terms, a partial order on partial terms is employed to formalise convergence of reductions. We consider both a weak and a strong notion of convergence and show that the metric model of convergence coincides with th...... to the metric setting -- orthogonal systems are both infinitarily confluent and infinitarily normalising in the partial order setting. The unique infinitary normal forms that the partial order model admits are Böhm trees....

  6. NCI Dictionary of Genetics Terms

    Science.gov (United States)

    A dictionary of more than 150 genetics-related terms written for healthcare professionals. This resource was developed to support the comprehensive, evidence-based, peer-reviewed PDQ cancer genetics information summaries.

  7. Definitions of Health Terms: Minerals

    Science.gov (United States)

    ... gov/definitions/mineralsdefinitions.html Definitions of Health Terms : Minerals To use the sharing features on this page, ... National Institutes of Health, Office of Dietary Supplements Minerals Minerals are those elements on the earth and ...

  8. Radiation protection. Terms and definitions

    Energy Technology Data Exchange (ETDEWEB)

    1981-04-01

    An alphabetical list in German is given of all terms and definitions important to radiation protection under consideration of all Austrian laws concerning this subject scope as also pertinent standards of ISO, DIN and OENORM.

  9. Supernatural A-Term Inflation

    Science.gov (United States)

    Lin, Chia-Min; Cheung, Kingman

    Following Ref. 10, we explore the parameter space of the case when the supersymmetry (SUSY) breaking scale is lower, for example, in gauge mediated SUSY breaking model. During inflation, the form of the potential is V0 plus MSSM (or A-term) inflation. We show that the model works for a wide range of the potential V0 with the soft SUSY breaking mass m O(1) TeV. The implication to MSSM (or A-term) inflation is that the flat directions which is lifted by the non-renormalizable terms described by the superpotential W=λ p φ p-1/Mp-3 P with p = 4 and p = 5 are also suitable to be an inflaton field for λp = O(1) provided there is an additional false vacuum term V0 with appropriate magnitude. The flat directions correspond to p = 6 also works for 0 < ˜ V0/M_ P4 < ˜ 10-40.

  10. Long term complications of diabetes

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000327.htm Long-term complications of diabetes To use the sharing features on this page, ... other tests. All these may help you keep complications of diabetes away. You will need to check your blood ...

  11. Option-implied term structures

    OpenAIRE

    Vogt, Erik

    2014-01-01

    The illiquidity of long-maturity options has made it difficult to study the term structures of option spanning portfolios. This paper proposes a new estimation and inference framework for these option-implied term structures that addresses long-maturity illiquidity. By building a sieve estimator around the risk-neutral valuation equation, the framework theoretically justifies (fat-tailed) extrapolations beyond truncated strikes and between observed maturities while remaining nonparametric. Ne...

  12. [Long-term psychiatric hospitalizations].

    Science.gov (United States)

    Plancke, L; Amariei, A

    2017-02-01

    Long-term hospitalizations in psychiatry raise the question of desocialisation of the patients and the inherent costs. Individual indicators were extracted from a medical administrative database containing full-time psychiatric hospitalizations for the period 2011-2013 of people over 16 years old living in the French region of Nord-Pas-de-Calais. We calculated the proportion of people who had experienced a hospitalization with a duration of 292 days or more during the study period. A bivariate analysis was conducted, then ecological data (level of health-care offer, the deprivation index and the size of the municipalities of residence) were included into a multilevel regression model in order to identify the factors significantly related to variability of long-term hospitalization rates. Among hospitalized individuals in psychiatry, 2.6% had had at least one hospitalization of 292 days or more during the observation period; the number of days in long-term hospitalization represented 22.5% of the total of days of full-time hospitalization in psychiatry. The bivariate analysis revealed that seniority in the psychiatric system was strongly correlated with long hospitalization rates. In the multivariate analysis, the individual indicators the most related to an increased risk of long-term hospitalization were: total lack of autonomy (OR=9.0; 95% CI: 6.7-12.2; P<001); diagnoses of psychological development disorders (OR=9.7; CI95%: 4.5-20.6; P<.001); mental retardation (OR=4.5; CI95%: 2.5-8.2; P<.001): schizophrenia (OR=3.0; CI95%: 1.7-5.2; P<.001); compulsory hospitalization (OR=1.7; CI95%: 1.4-2.1; P<.001); having experienced therapeutic isolation (OR=1.8; CI95%: 1.5-2.1; P<.001). Variations of long-term hospitalization rates depending on the type of establishment were very high, but the density of hospital beds or intensity of ambulatory activity services were not significantly linked to long-term hospitalization. The inhabitants of small urban units had

  13. Design parameters and source terms: Volume 3, Source terms

    International Nuclear Information System (INIS)

    1987-10-01

    The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report by Stearns Catalytic Corporation (SCC), entitled ''Design Parameters and Source Terms for a Two-Phase Repository in Salt,'' 1985, to the level of the Site Characterization Plan - Conceptual Design Report. The previous unpublished SCC Study identifies the data needs for the Environmental Assessment effort for seven possible Salt Repository sites. 11 refs., 9 tabs

  14. History of the term prostate.

    Science.gov (United States)

    Josef Marx, Franz; Karenberg, Axel

    2009-02-01

    We comprehensively review the history of the word "prostate" and related terms from 600 BC to the present. Both medical and non-medical ancient texts were searched to clarify the term's etymology and use. Anatomy textbooks of the 16th through the 18th century were analyzed to identify descriptions, illustrations and various expressions used by contemporary authors to designate the prostate. In ancient Greek the masculine term "prostatēs" meant "president" and was exclusively used in a non-medical sense. It was not until the Renaissance that anatomists discovered the organ naming it "glandulous body." In 1600 the French physician du Laurens introduced the metaphoric denomination "prostatae." However he and his contemporaries misinterpreted the history of the organ and the term, choose the wrong gender when translating it into Latin, and believed that it designated a double organ. Only in the 1800s was this anatomical error corrected while the grammatical one lived on. The history of the term "prostate" is a prime example of the difficulties with which the development of a precise urologic terminology had to struggle. At the same time this retrospective view provides a stimulus to avoid linguistic ambiguity in the future.

  15. FlexiTerm: a flexible term recognition method

    NARCIS (Netherlands)

    Spasic, I.; Greenwood, M.; Preece, A.; Francis, N.; Elwyn, G.

    2013-01-01

    BACKGROUND: The increasing amount of textual information in biomedicine requires effective term recognition methods to identify textual representations of domain-specific concepts as the first step toward automating its semantic interpretation. The dictionary look-up approaches may not always be

  16. Analysing long term discursive processes

    DEFF Research Database (Denmark)

    Horsbøl, Anders

    which extend beyond the single interaction, for instance negotiations or planning processes, seems to have played a less important role, with studies such as Iedema 2001 and Wodak 2000 as exceptions. These long term processes, however, are central to the constitution and workings of organizations......What do timescales - the notion that processes take place or can be viewed within a shorter or longer temporal range (Lemke 2005) - mean for the analysis of discourse? What are the methodological consequences of analyzing discourse at different timescales? It may be argued that discourse analysis...... in general has favored either the analysis of short term processes such as interviews, discussions, and lessons, or the analysis of non-processual entities such as (multimodal) texts, arguments, discursive repertoires, and discourses (in a Foucaultian sense). In contrast, analysis of long term processes...

  17. Sportsman's hernia? An ambiguous term.

    Science.gov (United States)

    Dimitrakopoulou, Alexandra; Schilders, Ernest

    2016-04-01

    Groin pain is common in athletes. Yet, there is disagreement on aetiology, pathomechanics and terminology. A plethora of terms have been employed to explain inguinal-related groin pain in athletes. Recently, at the British Hernia Society in Manchester 2012, a consensus was reached to use the term inguinal disruption based on the pathophysiology while lately the Doha agreement in 2014 defined it as inguinal-related groin pain, a clinically based taxonomy. This review article emphasizes the anatomy, pathogenesis, standard clinical assessment and imaging, and highlights the treatment options for inguinal disruption.

  18. A Short Term Analogue Memory

    DEFF Research Database (Denmark)

    Shah, Peter Jivan

    1992-01-01

    A short term analogue memory is described. It is based on a well-known sample-hold topology in which leakage currents have been minimized partly by circuit design and partly by layout techniques. Measurements on a test chip implemented in a standard 2.4 micron analogue CMOS process show a droop...

  19. The first term of plethysms

    OpenAIRE

    Iijima, Kazuto

    2011-01-01

    Plethysm of two Schur functions can be expressed as a linear combination of Schur functions, and monomial symmetric functions. In this paper, we express the coefficients combinatorially in the case of monomial symmetric functions. And by using it, we determine the first term of the plethysm with respect to Schur functions under the reverse lexicographic order.

  20. Long term radioactive waste management

    International Nuclear Information System (INIS)

    Lavie, J.M.

    1984-01-01

    In France, waste management, a sensitive issue in term of public opinion, is developing quickly, and due to twenty years of experience, is now reaching maturity. With the launching of the French nuclear programme, the use of radioactive sources in radiotherapy and industry, waste management has become an industrial activity. Waste management is an integrated system dealing with the wastes from their production to the long term disposal, including their identification, sortage, treatment, packaging, collection and transport. This system aims at guaranteing the protection of present and future populations with an available technology. In regard to their long term management, and the design of disposals, radioactive wastes are divided in three categories. This classification takes into account the different radioisotopes contained, their half life and their total activity. Presently short-lived wastes are stored in the shallowland disposal of the ''Centre de la Manche''. Set up within the French Atomic Energy Commission (CEA), the National Agency for waste management (ANDRA) is responsible within the framework of legislative and regulatory provisions for long term waste management in France [fr

  1. Nuclear engineering terms and definitions

    International Nuclear Information System (INIS)

    1981-01-01

    The most important nuclear engineering's terms and definitions are given in this standard. The definitions take into account the Austrian Regulations for Radiation Protection, for and pertinent ISO and DIN-Standards as also the OENORM A7006 and OENORM A6601. (M.T.)

  2. Defense Acquisitions Acronyms and Terms

    Science.gov (United States)

    2012-12-01

    DR Decision Review DRMO Defense Reutilization Marketing Office DRPM Direct Reporting Program Manager DSAA Defense Security Assistance Agency...STE Special Test Equipment STEP Simulation, Test, and Evaluation Process STLDD Software Top Level Design Document STP Software Test Plan STPR...established catalog or market prices for specific tasks under standard commercial terms and conditions; this does not include services sold based

  3. Some aspects of q-boson calculus

    International Nuclear Information System (INIS)

    Smirnov, Yu.F.; Kibler, M.R.

    1992-10-01

    The Jordan-Schwinger calculus is discussed, using deformed bosons. This work constitutes a first step toward a complete study of the SU q (2) unit tensor. The objective is to find a realization of the components of this tensor in terms of q-bosons. The q-deformed Schwinger algebra relative to SU q (2) is defined, and an algorithm for producing recurrent relations between Clebsch-Gordan coefficients for SU q (2) is given. (K.A.) 18 refs

  4. Algebra of constraints for a string in curved background

    International Nuclear Information System (INIS)

    Wess, J.

    1990-01-01

    A string field theory with curved background develops anomalies and Schwinger terms in the conformal algebra. It is generally believed that these Schwinger terms and anomalies are expressible in terms of the curvature tensor of the background metric and that, therefore, they are covariant under a change of coordinates in the target space. As far as I know, all the relevant computations have been done in special gauges, i.e. in Riemann normal coordinates. The question remains whether this is true in any gauge. We have tried to investigate this problem in a Hamiltonian formulation of the model. A classical Lagrangian serves to define the canonical variables and the classical constraints. They are expressed in terms of the canonical variables and, classically, they are first class. When quantized, an ordering prescription has to be imposed which leads to anomalies and Schwinger terms. We then try to redefine the constraints in such a way that the Schwinger terms depend on the curvature tensor only. The redefinition of the constraints is limited by the requirement that it should be local and that the energy momentum tensor should be conserved. In our approach, it is natural that the constraints are improved, order by order, in the number of derivatives: We find that, up to third order in the derivatives, Schwinger terms and anomalies are expressible in terms of the curvature tensor. In the fourth order of the derivatives however, we find a contribution to the Schwinger terms that cannot be removed by a redefinition and that cannot be cast in a covariant form. The anomaly on the other hand is fully expressible in terms of the curvature scalar. The energy momentum tensor ceases to be symmetric which indicates a Lorentz anomaly as well. The question remains if the Schwinger terms take a covariant form if we allow Einstein anomalies as well. (orig.)

  5. Random walk term weighting for information retrieval

    DEFF Research Database (Denmark)

    Blanco, R.; Lioma, Christina

    2007-01-01

    We present a way of estimating term weights for Information Retrieval (IR), using term co-occurrence as a measure of dependency between terms.We use the random walk graph-based ranking algorithm on a graph that encodes terms and co-occurrence dependencies in text, from which we derive term weights...

  6. Nuclear Energy, Long Term Requirements

    International Nuclear Information System (INIS)

    Knapp, V.

    2006-01-01

    There are serious warnings about depletion of oil and gas and even more serious warnings about dangers of climate change caused by emission of carbon dioxide. Should developed countries be called to replace CO2 emitting energy sources as soon as possible, and the time available may not be longer then few decades, can nuclear energy answer the call and what are the requirements? Assuming optimistic contribution of renewable energy sources, can nuclear energy expand to several times present level in order to replace large part of fossil fuels use? Paper considers intermediate and long-term requirements. Future of nuclear power depends on satisfactory answers on several questions. First group of questions are those important for near and intermediate future. They deal with economics and safety of nuclear power stations in the first place. On the same time scale a generally accepted concept for radioactive waste disposal is also required. All these issues are in the focus of present research and development. Safer and more economical reactors are targets of international efforts in Generation IV and INPRO projects, but aiming further ahead these innovative projects are also addressing issues such as waste reduction and proliferation resistance. However, even assuming successful technical development of these projects, and there is no reason to doubt it, long term and large-scale nuclear power use is thereby not yet secured. If nuclear power is to play an essential role in the long-term future energy production and in reduction of CO2 emission, than several additional questions must be replied. These questions will deal with long-term nuclear fuel sufficiency, with necessary contribution of nuclear power in sectors of transport and industrial processes and with nuclear proliferation safety. This last issue is more political then technical, thus sometimes neglected by nuclear engineers, yet it will have essential role for the long-term prospects of nuclear power. The

  7. Mercy as a Theological Term

    Directory of Open Access Journals (Sweden)

    Wojciech Zyzak

    2015-04-01

    Full Text Available The author of the article analyses different meanings of the term ‘mercy’. He begins with the ancient use of the word by pagan philosophers. This is the background for the analysis of the term ‘mercy’ in the Old and New Testament. The biblical sources lead to the definition of dogmatic foundations of God’s Mercy and allow the ethical and moral aspects of the human mercy to be shown. Closely connected with the last is the social dimension of the mercy. The author also deals with other dimensions of the mercy, such as: pastoral, liturgical, psychological and juridical. He also discusses the meaning of the mercy in the spirituality and Christian art.

  8. Comparing long term energy scenarios

    International Nuclear Information System (INIS)

    Cumo, M.; Simbolotti, G.

    2001-01-01

    Major projection studies by international organizations and senior analysts have been compared with reference to individual key parameters (population, energy demand/supply, resources, technology, emissions and global warming) to understand trends and implications of the different scenarios. Then, looking at the long term (i.e., 2050 and beyond), parameters and trends have been compared together to understand and quantify whether and when possible crisis or market turbulence might occur due to shortage of resources or environmental problems [it

  9. Short-term countermeasures questionnaire

    International Nuclear Information System (INIS)

    Hogan, R.

    1995-01-01

    This document presents the analysis of a questionnaire transmitted to fourteen countries. The questions were about shot-term countermeasures countries have implemented in case of a nuclear accident. Those questions concerned the main different aspects of the issue, such as the objective of the countermeasures implemented, the kind of measures depending on the people concerned (emergency workers or not, children, pregnant women...), or the use of stable iodine in order to avoid a contamination. (TEC)

  10. Glossary on peaceful nuclear explosions terms

    International Nuclear Information System (INIS)

    1980-01-01

    The report presents a glossary of terms in the area of peaceful nuclear explosions. The terms are in English, French, Russian and Spanish with cross-references for the corresponding terms of the other languages

  11. Super-Hopf realizations of Lie superalgebras: Braided Paraparticle extensions of the Jordan-Schwinger map

    International Nuclear Information System (INIS)

    Kanakoglou, K.; Daskaloyannis, C.; Herrera-Aguilar, A.

    2010-01-01

    The mathematical structure of a mixed paraparticle system (combining both parabosonic and parafermionic degrees of freedom) commonly known as the Relative Parabose Set, will be investigated and a braided group structure will be described for it. A new family of realizations of an arbitrary Lie superalgebra will be presented and it will be shown that these realizations possess the valuable representation-theoretic property of transferring invariably the super-Hopf structure. Finally two classes of virtual applications will be outlined: The first is of interest for both mathematics and mathematical physics and deals with the representation theory of infinite dimensional Lie superalgebras, while the second is of interest in theoretical physics and has to do with attempts to determine specific classes of solutions of the Skyrme model.

  12. Complex Kohn variational principle for the solution of Lippmann-Schwinger equations

    International Nuclear Information System (INIS)

    Adhikari, S.K.

    1992-07-01

    A recently proposed version of the Kohn variational principle for the t matrix incorporating the correct boundary condition is applied for the first time to the study of nucleon-nucleon scattering. Analytic expressions can be obtained for all the integrals in the method for a wide class of potentials and for a suitable choice of trial functions. Closed-form analytic expressions for these integrals are given for Yakawa and exponential potentials. Calculations with two commonly used S-wave nucleon-nucleon potentials show that the method may converge faster than other solution schemes not only for the phase-shifts but also for the off-shell t matrix elements if the freedom in the choice of the trial function is exploited. (author)

  13. Schwinger variational principle in charged particle scattering by mesic atoms and atoms

    International Nuclear Information System (INIS)

    Zubarev, A.L.; Podkopaev, A.P.

    1981-01-01

    The way for solving the strong channel coupling method equation with the use of the Shcwinger variational method is proposed. The equation obtained is valid for atomic and mesoatomic physics when the account of the large number of closed channels is necessary and virtual transitions in continuum. In this variational method the trial functions are chosen in the form of expansion into eigenfunctions. The region of the equation validity is found. The problems of the e + H and p-dμ scattering are studied. The e + H scattering length turns out to be 1.8 a. u. which is in accordance with other results. The scattering cross section for p-dμ scattering is equal to 5.7x10 -21 cm -2 which also qualitatively is in agreement with results obtained elsewhere. The bound state which is stable relative to the decay into a positron and hydrogen atom is found for the e + H system [ru

  14. Dynamically assisted Schwinger effect beyond the spatially-uniform-field approximation

    Science.gov (United States)

    Aleksandrov, I. A.; Plunien, G.; Shabaev, V. M.

    2018-06-01

    We investigate the phenomenon of electron-positron pair production from vacuum in the presence of a strong electric field superimposed by a weak but fast varying pulse which substantially increases the total particle yield. We employ a nonperturbative numerical technique and perform the calculations beyond the spatially-uniform-field approximation, i.e., dipole approximation, taking into account the coordinate dependence of the fast component. The analysis of the main characteristics of the pair-production process (momentum spectra of particles and total amount of pairs) reveals a number of important features which are absent within the previously used approximation. In particular, the structure of the momentum distribution is modified both qualitatively and quantitatively, and the total number of pairs created as well as the enhancement factor due to dynamical assistance become significantly smaller.

  15. Schwinger functions for the Yukawa model in two dimensions with space-time cutoff

    International Nuclear Information System (INIS)

    Seiler, E.

    1975-01-01

    It is shown that a Euclidean version of the formulae of Matthews and Salam for the Green's functions of a two-dimensional Yukawa model with interaction in a finite space-time volume makes sense, if renormalized correctly. (orig.) [de

  16. Pennsylvania Source Term Tracking System

    International Nuclear Information System (INIS)

    1992-08-01

    The Pennsylvania Source Term Tracking System tabulates surveys received from radioactive waste generators in the Commonwealth of radioactive waste is collected each quarter from generators using the Low-Level Radioactive Waste Management Quarterly Report Form (hereafter called the survey) and then entered into the tracking system data base. This personal computer-based tracking system can generate 12 types of tracking reports. The first four sections of this reference manual supply complete instructions for installing and setting up the tracking system on a PC. Section 5 presents instructions for entering quarterly survey data, and Section 6 discusses generating reports. The appendix includes samples of each report

  17. Severe accident source term reassessment

    International Nuclear Information System (INIS)

    Hazzan, M.J.; Gardner, R.; Warman, E.A.; Jacobs, S.B.

    1987-01-01

    This paper summarizes the status of the reassessment of severe reactor accident source terms, which are defined as the quantity, type, and timing of fission product releases from such accidents. Concentration is on the major results and conclusions of analyses with modern methods for both pressurized water reactors (PWRs) and boiling water reactors (BWRs), and the special case of containment bypass. Some distinctions are drawn between analyses for PWRs and BWRs. In general, the more the matter is examined, the consequences, or probability of serious consequences, seem to be less. (author)

  18. Asymptomatic thrombocytopenia at term pregnancy

    International Nuclear Information System (INIS)

    Alam, M.; Ansari, A.

    2007-01-01

    This study was carried out to assess the platelet count in asymptomatic pregnant women at the time of delivery in local population. Six hundred and eighteen healthy pregnant women and 100 aged matched non-pregnant healthy women were randomly selected for the study and their platelet counts were estimated. Out of total 618 pregnant women at the time of delivery, 34 (5.5%) were having platelet count < 150x109/L and only 4 (0.65%) less than 100x109/L. All the thrombocytopaenic women were asymptomatic. About 5% of healthy women at term pregnancy are likely to have mild thrombocytopenia without suffering from any untoward clinical consequences. (author)

  19. Long-term biodosimetry Redux

    International Nuclear Information System (INIS)

    Simon, Steven L.; Bouville, Andre

    2016-01-01

    This paper revisits and reiterates the needs, purposes and requirements of bio-dosimetric assays for long-term dose and health risk assessments. While the most crucial need for bio-dosimetric assays is to guide medical response for radiation accidents, the value of such techniques for improving our understanding of radiation health risk by supporting epidemiological (long-term health risk) studies is significant. As new cohorts of exposed persons are identified and new health risk studies are undertaken with the hopes that studying the exposed will result in a deeper understanding of radiation risk, the value of reliable dose reconstruction is underscored. The ultimate application of biodosimetry in long-term health risk studies would be to completely replace model-based dose reconstruction-a complex suite of methods for retrospectively estimating dose that is commonly fraught with large uncertainties due to the absence of important exposure-related information, as well as imperfect models. While biodosimetry could potentially supplant model-based doses, there are numerous limitations of presently available techniques that constrain their widespread application in health risk research, including limited ability to assess doses received far in the past, high cost, great inter-individual variability, invasiveness, higher than preferred detection limits and the inability to assess internal dose (for the most part). These limitations prevent the extensive application of biodosimetry to large cohorts and should be considered a challenge to researchers to develop new and more flexible techniques that meet the demands of long-term health risk research. Events in recent years, e.g. the Fukushima reactor accident and the increased threat of nuclear terrorism, underscore that any event that results in significant radiation exposures of a group of people will also produce a much larger population, exposed at lower levels, but that likewise needs (or demands) an exposure

  20. Termómetro digital

    OpenAIRE

    Olivar Ruiz, Marta

    2015-01-01

    En este trabajo de fin de grado se ha realizado un termómetro digital utilizando Arduino, plataforma hardware y software basada en microcontroladores comerciales integrados en una PCB y un display digital. Como transductor de temperatura se emplea el termopar de tipo K. Se abarcan todas las etapas, desde el diseño del circuito electrónico hasta la fabricación del prototipo. El circuito electrónico diseñado realiza el acondicionamiento de las señales, tanto del termopar como del sensor de temp...

  1. Near-term market conditions

    International Nuclear Information System (INIS)

    Patterson, J.A.

    1979-01-01

    Information is reviewed available to DOE on uranium marketing and price situation. It is concluded that past procurement activity and slippage in needs has placed the uranium users in a comfortable supply position for the next few years. As a consequence, there has been a relatively low level of procurement activity the last few years, which have been accompanied by price stability. U.S. procurement has strongly favored U.S. suppliers, however, the potential exists for procurement of foreign uranium, particularly in long-term contracts. Domestic producers, having expanded their production and sales capability, will be in a strong position for deliveries over the next several years

  2. Do perfume additives termed human pheromones warrant being termed pheromones?

    Science.gov (United States)

    Winman, Anders

    2004-09-30

    Two studies of the effects of perfume additives, termed human pheromones by the authors, have conveyed the message that these substances can promote an increase in human sociosexual behaviour [Physiol. Behav. 75 (2003) R1; Arch. Sex. Behav. 27 (1998) R2]. The present paper presents an extended analysis of this data. It is shown that in neither study is there a statistically significant increase in any of the sociosexual behaviours for the experimental groups. In the control groups of both studies, there are, however, moderate but statistically significant decreases in the corresponding behaviour. Most notably, there is no support in data for the claim that the substances increase the attractiveness of the wearers of the substances to the other sex. It is concluded that more research using matched homogenous groups of participants is needed. Copyright 2004 Elsevier Inc.

  3. TRANSITION IN TERMS OF GLOBALISATION

    Directory of Open Access Journals (Sweden)

    Miroslav Milutinović

    2014-10-01

    Full Text Available One of the essential constituents of the term transition, in Serbia as well as in other postsocialistic countries, refers to the transition from one development concept onto another one (extensive and mobilising, which is completely different (market-based and innovation-oriented. Market behaviour rules have changed to a great extent, as well as the increasingly present innovations in the field of technology, and introduced certain innovations in business orientation of companies. The struggle for market share is becoming more aggressive and dynamic enabling the survival of exclusively those companies which have implanted high flexibility and innovation levels into their business ambience. Globalisation is inherent in capitalism, it is its constituent logic. In future, new rules will have to be brought which would allow of the managment function to be performed within the complete business policy mutually agreed upon betwen the representatives of the capital owner and those of the personell. These regulations are necessary for long-term efficiency and profitability of private sector, as well as for the final success of economy.

  4. Uranium ... long-term confidence

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Half way through 1983 the outlook for the world's uranium producers was far from bright if one takes a short term view. The readily accessible facts present a gloomy picture. The spot prices of uranium over the past few years decreased from a high of $42-$43/lb to a low of $17 in 1982. It now hovers between $23 and $24. the contract prices negotiated between producers and consumers are not so accessible but they do not reflect the spot price. The reasons why contractual uranium prices do not follow the usual dictates of supply and demand are related to the position in which uranium and associated power industries find themselves. There is public reaction with strong emotional overtones as well as much reduced expectations about the electric power needs of the world. Furthermore the supply of uranium is not guaranteed despite present over production. However the people in the industry, taking the medium- and long-term view, are not despondent

  5. Long term stability of power systems

    Energy Technology Data Exchange (ETDEWEB)

    Kundur, P; Gao, B [Powertech Labs. Inc., Surrey, BC (Canada)

    1994-12-31

    Power system long term stability is still a developing subject. In this paper we provide our perspectives and experiences related to long term stability. The paper begins with the description of the nature of the long term stability problem, followed by the discussion of issues related to the modeling and solution techniques of tools for long term stability analysis. Cases studies are presented to illustrate the voltage stability aspect and plant dynamics aspect of long term stability. (author) 20 refs., 11 figs.

  6. Navigating Long-Term Care

    Directory of Open Access Journals (Sweden)

    James D. Holt MD

    2017-03-01

    Full Text Available Americans over age 65 constitute a larger percentage of the population each year: from 14% in 2010 (40 million elderly to possibly 20% in 2030 (70 million elderly. In 2015, an estimated 66 million people provided care to the ill, disabled, and elderly in the United States. In 2000, according to the Centers for Disease Control and Prevention (CDC, 15 million Americans used some form of long-term care: adult day care, home health, nursing home, or hospice. In all, 13% of people over 85 years old, compared with 1% of those ages 65 to 74, live in nursing homes in the United States. Transitions of care, among these various levels of care, are common: Nursing home to hospital transfer, one of the best-studied transitions, occurs in more than 25% of nursing home residents per year. This article follows one patient through several levels of care.

  7. Refining search terms for nanotechnology

    International Nuclear Information System (INIS)

    Porter, Alan L.; Youtie, Jan; Shapira, Philip; Schoeneck, David J.

    2008-01-01

    The ability to delineate the boundaries of an emerging technology is central to obtaining an understanding of the technology's research paths and commercialization prospects. Nowhere is this more relevant than in the case of nanotechnology (hereafter identified as 'nano') given its current rapid growth and multidisciplinary nature. (Under the rubric of nanotechnology, we also include nanoscience and nanoengineering.) Past efforts have utilized several strategies, including simple term search for the prefix nano, complex lexical and citation-based approaches, and bootstrapping techniques. This research introduces a modularized Boolean approach to defining nanotechnology which has been applied to several research and patenting databases. We explain our approach to downloading and cleaning data, and report initial results. Comparisons of this approach with other nanotechnology search formulations are presented. Implications for search strategy development and profiling of the nanotechnology field are discussed

  8. Refining search terms for nanotechnology

    Energy Technology Data Exchange (ETDEWEB)

    Porter, Alan L. [Georgia Institute of Technology (United States); Youtie, Jan [Georgia Institute of Technology, Enterprise Innovation Institute (United States)], E-mail: jan.youtie@innovate.gatech.edu; Shapira, Philip [Georgia Institute of Technology (United States); Schoeneck, David J. [Search Technology, Inc. (United States)

    2008-05-15

    The ability to delineate the boundaries of an emerging technology is central to obtaining an understanding of the technology's research paths and commercialization prospects. Nowhere is this more relevant than in the case of nanotechnology (hereafter identified as 'nano') given its current rapid growth and multidisciplinary nature. (Under the rubric of nanotechnology, we also include nanoscience and nanoengineering.) Past efforts have utilized several strategies, including simple term search for the prefix nano, complex lexical and citation-based approaches, and bootstrapping techniques. This research introduces a modularized Boolean approach to defining nanotechnology which has been applied to several research and patenting databases. We explain our approach to downloading and cleaning data, and report initial results. Comparisons of this approach with other nanotechnology search formulations are presented. Implications for search strategy development and profiling of the nanotechnology field are discussed.

  9. Coming to terms with fear

    Science.gov (United States)

    LeDoux, Joseph E.

    2014-01-01

    The brain mechanisms of fear have been studied extensively using Pavlovian fear conditioning, a procedure that allows exploration of how the brain learns about and later detects and responds to threats. However, mechanisms that detect and respond to threats are not the same as those that give rise to conscious fear. This is an important distinction because symptoms based on conscious and nonconscious processes may be vulnerable to different predisposing factors and may also be treatable with different approaches in people who suffer from uncontrolled fear or anxiety. A conception of so-called fear conditioning in terms of circuits that operate nonconsciously, but that indirectly contribute to conscious fear, is proposed as way forward. PMID:24501122

  10. Apnea in the term infant.

    Science.gov (United States)

    Patrinos, Mary Elaine; Martin, Richard J

    2017-08-01

    Whereas apnea of prematurity has been well defined and its pathophysiology extensively studied, apnea in the term infant remains a greater challenge. Unfortunately, clear diagnostic criteria are lacking and pathogenesis and management vary widely. In this review we have arbitrarily organized the discussion chronologically into earlier and later postnatal periods. In the first days of life, presumed apnea may reflect physiologic events such as positional or feeding etiologies, or may be a manifestation of serious pathophysiology, such as a seizure disorder. Beyond the neonatal period, presumed apnea may be characterized as a BRUE event (brief resolved unexplained event; formerly referred to as ALTE: apparent life-threatening event) and most frequently a precipitating event cannot be identified. Medical providers are left with somewhat of a dilemma regarding the need to hospitalize and/or work up such patients. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Standartization and Terminography of New Construction Terms

    Directory of Open Access Journals (Sweden)

    Zofija Babickienė

    2011-06-01

    Full Text Available The past ten year period showed the occurance of a great number of new construction terms in the Lithua- nian language. Thus it is necessary to collect and systematize construction terms, terminoids, quasi-terms and standardize them from the point of view of the Standard Lithuanian Language taking into account both logic and terminology requirements. This article deals with modern construction terms from the point of view of the Standard Lithuanian Language including newest data bases saving all actual information on them. The reseach showed that The Dictionary of Construction Terms (2003 ought to be included into The Lithuanian language Term Bank (http://terminai.vlkk.lt. It is necessary to be done for the following reasons. Firstly, because of the creation and standartization as well as sistematization process of new construction terms. Secondly, for the development of continuous scientific discusion and successful professional education. It was established that a certain number of construction terms from the point of view of the Standard Lithuanian Language should be included into new Dictionary of Construction Terms as well as into Term Bank of the Lithuanian Republic. The terms analysed in the article are concerning basement types, pile types, construction joints, also details of walls, roofs, chimneys, construction materials and etc. The analysis showed how different morphological variants and undesirable synonymous terms occur. Finally, the analysis helped to identify that the informal terms mix with formal, standard terms and conclude in incorrect term usage.

  12. Short-term decisions under long-term uncertainty

    International Nuclear Information System (INIS)

    Tol, R.S.J.

    1998-01-01

    The behaviour of future policy-makers substantially influences future greenhouse gas emissions. Uncertainty about the motives of future policy-makers may thus strongly influence the climate policy strategies of current policy-makers. Analytical and numerical analyses in this paper confirm this hypothesis. If current policy-makers want to constrain emissions accumulated over a prolonged period of time, and if future policy-makers tend, with a certain chance, to a less ambitious climate policy, then current policy-makers should intensify their efforts to reduce emissions and the cost of emission reduction. In this setting, if current policy-makers want to meet a cumulative emission constraint in expectation, then the preferred policy trajectory does not qualitatively deviate from one suggested by a standard cost-effective trajectory. If, however, the constraint is to be met with a certain probability, then the importance of early action is enhanced relative to that of postponed action. Costs substantially increase if current policy-makers want to set long-term goals without the full cooperation of future policy-makers. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  13. Measurement of global and local resonance terms

    CERN Document Server

    Tomás, R; Calaga, R; Fischer, W; Franchi, A; Rumolo, Giovanni

    2005-01-01

    Recently, resonance driving terms were successfully measured in the CERN SPS and the BNL RHIC from the Fourier spectrum of beam position monitor (BPM) data. Based on these measurements a new analysis has been derived to extract truly local observables from BPM data. These local observables are called local resonance terms since they share some similarities with the global resonance terms. In this paper we derive these local terms analytically and present experimental measurements of sextupolar global and local resonance terms in RHIC. Nondestructive measurements of these terms using ac dipoles are also presented.

  14. Long term study of mechanical

    Directory of Open Access Journals (Sweden)

    Ahmed M. Diab

    2016-06-01

    Full Text Available In this study, properties of limestone cement concrete containing different replacement levels of limestone powder were examined. It includes 0%, 5%, 10%, 15%, 20% and 25% of limestone powder as a partial replacement of cement. Silica fume was added incorporated with limestone powder in some mixes to enhance the concrete properties. Compressive strength, splitting tensile strength and modulus of elasticity were determined. Also, durability of limestone cement concrete with different C3A contents was examined. The weight loss, length change and cube compressive strength loss were measured for concrete attacked by 5% sodium sulfate using an accelerated test up to 525 days age. The corrosion resistance was measured through accelerated corrosion test using first crack time, cracking width and steel reinforcement weight loss. Consequently, for short and long term, the use of limestone up to 10% had not a significant reduction in concrete properties. It is not recommended to use blended limestone cement in case of sulfate attack. The use of limestone cement containing up to 25% limestone has insignificant effect on corrosion resistance before cracking.

  15. Long-term competence restoration.

    Science.gov (United States)

    Morris, Douglas R; DeYoung, Nathaniel J

    2014-01-01

    While the United States Supreme Court's Jackson v. Indiana decision and most state statutes mandate determinations of incompetent defendants' restoration probabilities, courts and forensic clinicians continue to lack empirical evidence to guide these determinations and do not yet have a consensus regarding whether and under what circumstances incompetent defendants are restorable. The evidence base concerning the restoration likelihood of those defendants who fail initial restoration efforts is even further diminished and has largely gone unstudied. In this study, we examined the disposition of a cohort of defendants who underwent long-term competence restoration efforts (greater than six months) and identified factors related to whether these defendants were able to attain restoration and adjudicative success. Approximately two-thirds (n = 52) of the 81 individuals undergoing extended restoration efforts were eventually deemed restored to competence. Lengths of hospitalization until successful restoration are presented with implications for the reasonable length of time that restoration efforts should persist. Older individuals were less likely to be restored and successfully adjudicated, and individuals with more severe charges and greater factual legal understanding were more likely to be restored and adjudicated. The significance of these findings for courts and forensic clinicians is discussed.

  16. Onboard Short Term Plan Viewer

    Science.gov (United States)

    Hall, Tim; LeBlanc, Troy; Ulman, Brian; McDonald, Aaron; Gramm, Paul; Chang, Li-Min; Keerthi, Suman; Kivlovitz, Dov; Hadlock, Jason

    2011-01-01

    Onboard Short Term Plan Viewer (OSTPV) is a computer program for electronic display of mission plans and timelines, both aboard the International Space Station (ISS) and in ISS ground control stations located in several countries. OSTPV was specifically designed both (1) for use within the limited ISS computing environment and (2) to be compatible with computers used in ground control stations. OSTPV supplants a prior system in which, aboard the ISS, timelines were printed on paper and incorporated into files that also contained other paper documents. Hence, the introduction of OSTPV has both reduced the consumption of resources and saved time in updating plans and timelines. OSTPV accepts, as input, the mission timeline output of a legacy, print-oriented, UNIX-based program called "Consolidated Planning System" and converts the timeline information for display in an interactive, dynamic, Windows Web-based graphical user interface that is used by both the ISS crew and ground control teams in real time. OSTPV enables the ISS crew to electronically indicate execution of timeline steps, launch electronic procedures, and efficiently report to ground control teams on the statuses of ISS activities, all by use of laptop computers aboard the ISS.

  17. Long-term corrosion studies

    International Nuclear Information System (INIS)

    Gdowski, G.

    1998-01-01

    The scope of this activity is to assess the long-term corrosion properties of metallic materials under consideration for fabricating waste package containers. Three classes of metals are to be assessed: corrosion resistant, intermediate corrosion resistant, and corrosion allowance. Corrosion properties to be evaluated are general, pitting and crevice corrosion, stress-corrosion cracking, and galvanic corrosion. The performance of these materials will be investigated under conditions that are considered relevant to the potential emplacement site. Testing in four aqueous solutions, and vapor phases above them, and at two temperatures are planned for this activity. (The environmental conditions, test metals, and matrix are described in detail in Section 3.0.) The purpose and objective of this activity is to obtain the kinetic and mechanistic information on degradation of metallic alloys currently being considered for waste package containers. This information will be used to provide assistance to (1) waste package design (metal barrier selection) (E-20-90 to E-20-92), (2) waste package performance assessment activities (SIP-PA-2), (3) model development (E-20-75 to E-20-89). and (4) repository license application

  18. Terrorism: Current and Long Term Threats

    National Research Council Canada - National Science Library

    Jenkins, Brian

    2001-01-01

    Despite the high level of anxiety the American people are currently experiencing, we may still not fully comprehend the seriousness of the current and near-term threats we confront or the longer-term...

  19. The latest dictionary of nuclear energy term

    International Nuclear Information System (INIS)

    1996-06-01

    This book is the latest dictionary of nuclear energy term. It deals with explanations of nuclear energy term in alphabetical order. It also lists abbreviation of nuclear energy term. This book contains symbol and unit, radiation units, greek letters, the symbol of for element, the table of an isotope and the periodic table on nuclear power term. It includes glossary of nuclear power in Korean and French and conceptual map about development of nuclear power.

  20. The Lexicographic Treatment of Color Terms

    Science.gov (United States)

    Williams, Krista

    2014-01-01

    This dissertation explores the main question, "What are the issues involved in the definition and translation of color terms in dictionaries?" To answer this question, I examined color term definitions in monolingual dictionaries of French and English, and color term translations in bilingual dictionaries of French paired with nine…

  1. The Demonstration of Short-Term Consolidation.

    Science.gov (United States)

    Jolicoeur, Pierre; Dell'Acqua, Roberto

    1998-01-01

    Results of seven experiments involving 112 college students or staff using a dual-task approach provide evidence that encoding information into short-term memory involves a distinct process termed short-term consolidation (STC). Results suggest that STC has limited capacity and that it requires central processing mechanisms. (SLD)

  2. Basic Color Terms in Estonian Sign Language

    Science.gov (United States)

    Hollman, Liivi; Sutrop, Urmas

    2011-01-01

    The article is written in the tradition of Brent Berlin and Paul Kay's theory of basic color terms. According to this theory there is a universal inventory of eleven basic color categories from which the basic color terms of any given language are always drawn. The number of basic color terms varies from 2 to 11 and in a language having a fully…

  3. 7 CFR 1436.7 - Loan term.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Loan term. 1436.7 Section 1436.7 Agriculture... AGRICULTURE LOANS, PURCHASES, AND OTHER OPERATIONS FARM STORAGE FACILITY LOAN PROGRAM REGULATIONS § 1436.7 Loan term. (a) For eligible facility loan commodities other than sugar, the term of the loan will be 7...

  4. 24 CFR 573.4 - Loan term.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Loan term. 573.4 Section 573.4 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF... COMMUNITY FACILITIES LOAN GUARANTEE RECOVERY FUND § 573.4 Loan term. The term of the loan to be guaranteed...

  5. 24 CFR 1007.35 - Loan terms.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Loan terms. 1007.35 Section 1007.35... LOAN GUARANTEES FOR NATIVE HAWAIIAN HOUSING § 1007.35 Loan terms. To be eligible for guarantee under this part, the loan shall: (a) Be made for a term not exceeding 30 years; (b) Bear interest (exclusive...

  6. Term Bases and Linguistic Linked Open Data

    DEFF Research Database (Denmark)

    for pursuing their work. The theme of this year’s TKE is ‘Term Bases and Linguistic Linked Open Data’. Mono- and multi-lingual term bases, which contain information about concepts (terms, definitions, examples of use, references, comments on equivalence etc.), have always made up valuable linguistic resources...

  7. Long-term associative learning predicts verbal short-term memory performance

    OpenAIRE

    Jones, Gary; Macken, Bill

    2017-01-01

    Studies using tests such as digit span and nonword repetition have implicated short-term memory across a range of developmental domains. Such tests ostensibly assess specialized processes for the short-term manipulation and maintenance of information that are often argued to enable long-term learning. However, there is considerable evidence for an influence of long-term linguistic learning on performance in short-term memory tasks that brings into question the role of a specialized short-term...

  8. Term limits and the tobacco industry.

    Science.gov (United States)

    Apollonio, Dorie E; Glantz, Stanton A; Bero, Lisa A

    2014-03-01

    In the 1990s several American states passed term limits on legislators with the stated intention of reducing the influence of wealthy industries on career legislators. Although term limits in the United States do not have a direct relationship to public health, the tobacco industry anticipated that term limits could have indirect effects by either limiting or expanding industry influence. We detail the strategy of the tobacco industry in the wake of term limits using internal tobacco company documents and a database of campaign contributions made to legislators in term limited states between 1988 and 2002. Despite some expectations that term limits would limit tobacco industry access to state legislators, term limits appear to have had the opposite effect. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Financing long term liabilities (Germany)

    International Nuclear Information System (INIS)

    2003-01-01

    charges and fees levied from the waste producers. Altogether, financial resources for decommissioning are needed for the following steps: the post-operational phase in which the facility is prepared for dismantling after its final shut-down, dismantling of the radioactive part of the facility, management, storage and disposal of the radioactive waste, restoration of the site, licensing and regulatory supervision of all these steps. Additional means are necessary for the management, storage and disposal of the spent fuel. The way in which the availability of financial resources is secured differs between public owned installations and installations of the private power utilities. In Germany, past practices has resulted in singular contaminated sites of limited extent, mainly during the first half of the 20. century. Those contaminated sites have been or are being cleaned up and redeveloped. In large areas of Saxony and Thuringia, the geological formations permitted the surface and underground mining of Uranium ore. Facilities of the former Soviet-German WISMUT Ltd. where ore was mined and processed from 1946 until the early 1990's can be found at numerous sites. In the course of the re-unification of Germany, the soviet shares of the WISMUT were taken over by the Federal Republic of Germany and the closure of the WISMUT facilities was initiated. In that phase the extent of the damages to the environment and of the necessary remediation work became clear. All mining and milling sites are now closed and are under decommissioning. A comprehensive remediation concept covers all WISMUT sites. Heaps and mill-tailing ponds are transferred into a long-term stable condition. The area of the facilities to be remediated amounts to more than 30 km 2 . Heaps cover a total area of ca. 15,5 km 2 , tailing ponds in which the tailings resulting from the Uranium production are stored as sludges cover 6,3 km 2 ). In total, the remediation issues are very complex and without precedent. The

  10. Safety related terms for advanced nuclear plants

    International Nuclear Information System (INIS)

    1995-12-01

    The terms considered in this document are in widespread current use without a universal consensus as to their meaning. Other safety related terms are already defined in national or international codes and standards as well as in IAEA's Nuclear Safety Standards Series. Most of the terms in those codes and standards have been defined and used for regulatory purposes, generally for application to present reactor designs. There is no intention to duplicate the description of such regulatory terms here, but only to clarify the terms used for advanced nuclear plants. The following terms are described in this paper: Inherent safety characteristics, passive component, active component, passive systems, active system, fail-safe, grace period, foolproof, fault-/error-tolerant, simplified safety system, transparent safety

  11. Safety related terms for advanced nuclear plants

    International Nuclear Information System (INIS)

    1991-09-01

    The terms considered in this document are in widespread current use without a universal consensus as to their meaning. Other safety related terms are already defined in national or international codes and standards as well as in IAEA's Nuclear Safety Standards Series. Most of the terms in those codes and standards have been defined and used for regulatory purposes, generally for application to present reactor designs. There is no intention to duplicate the description of such regulatory terms here, but only to clarify the terms used for advanced nuclear plants. The following terms are described in this paper: Inherent safety characteristics, passive component, active component, passive systems, active system, fail-safe, grace period, foolproof, fault-/error-tolerant, simplified safety system, transparent safety

  12. Terms of payment in the sales contract

    OpenAIRE

    Harmáčková, Iva

    2009-01-01

    This thesis makes an analysis of price and terms of payment in the sales contract. Both elements are conceived in terms of legal framework and in terms of importance for the parties to an international sales contract. The theoretical part deals with the role of the sales contract in business relations, structure and legal norms of the international sales contract. The practical part includes an analysis of specific international sales contract.

  13. Sleep facilitates long-term face adaptation

    OpenAIRE

    Ditye, Thomas; Javadi, Amir Homayoun; Carbon, Claus-Christian; Walsh, Vincent

    2013-01-01

    Adaptation is an automatic neural mechanism supporting the optimization of visual processing on the basis of previous experiences. While the short-term effects of adaptation on behaviour and physiology have been studied extensively, perceptual long-term changes associated with adaptation are still poorly understood. Here, we show that the integration of adaptation-dependent long-term shifts in neural function is facilitated by sleep. Perceptual shifts induced by adaptation to a distorted imag...

  14. Inflation with Fayet-Iliopoulos terms

    International Nuclear Information System (INIS)

    Wieck, Clemens; Winkler, Martin Wolfgang

    2014-08-01

    Two of the most attractive realizations of inflation in supergravity are based upon the presence of a constant Fayet-Iliopoulos (FI) term. In D-term hybrid inflation it is the FI term itself which sets the energy scale of inflation. Alternatively, the breaking of a U(1) symmetry induced by the FI term can dynamically generate the quadratic potential of chaotic inflation. The purpose of this note is to study the possible UV embedding of these schemes in terms of the 'field-dependent FI term' related to a string modulus field which is stabilized by a non-perturbative superpotential. We find that in settings where the FI term drives inflation, gauge invariance prevents a decoupling of the modulus from the inflationary dynamics. The resulting inflation models generically contain additional dynamical degrees of freedom compared to D-term hybrid inflation. However, the dynamical realization of chaotic inflation can be obtained in complete analogy to the case of a constant FI term. We present a simple string-inspired toy model of this type.

  15. Information, polarization and term length in democracy

    DEFF Research Database (Denmark)

    Schultz, Christian

    2008-01-01

    This paper considers term lengths in a representative democracy where the political issue divides the population on the left-right scale. Parties are ideologically different and better informed about the consequences of policies than voters are. A short term length makes the government more...... accountable, but the re-election incentive leads to policy-distortion as the government seeks to manipulate swing voters' beliefs to make its ideology more popular. This creates a trade-off: A short term length improves accountability but gives distortions. A short term length is best for swing voters when...

  16. Long-range terms in atomic collisions

    International Nuclear Information System (INIS)

    McGuire, J.H.; Weaver, O.L.

    1986-01-01

    Various separations, or ''gauge choices,'' are possible for the decomposition of the total Hamiltonian into electronic and internuclear terms. We show that, for one particular choice, all long-range Coulomb terms are associated with the internuclear motion. The potential then associated with electronic transitions is non-Coulombic. Some practical consequences of this gauge choice are discussed

  17. 7 CFR 2201.19 - Loan terms.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Loan terms. 2201.19 Section 2201.19 Agriculture Regulations of the Department of Agriculture (Continued) LOCAL TELEVISION LOAN GUARANTEE BOARD LOCAL TELEVISION LOAN GUARANTEE PROGRAM-PROGRAM REGULATIONS Loan Guarantees § 2201.19 Loan terms. (a) All Loans...

  18. Long-Term Orientation in Trade

    NARCIS (Netherlands)

    Hofstede, G.J.; Jonker, C.M.; Verwaart, D.

    2008-01-01

    Trust does not work in the same way across cultures. This paper presents an agent model of behavior in trade across Hofstedes cultural dimension of long-term vs. short-term orientation. The situation is based on a gaming simulation, the Trust and Tracing game. The paper investigates the

  19. Term breech delivery in The Netherlands

    NARCIS (Netherlands)

    Rietberg, C.C.

    2006-01-01

    The management of the term breech delivery has been a subject of discussion for many years. Only a few randomized trials had been performed on outcome in relation to the mode of delivery in case of breech position. In october 2000 the results of the Term Breech Trial (TBT) were published, in which

  20. A Long-term Plan for Kalk

    DEFF Research Database (Denmark)

    2017-01-01

    In this case, the author demonstrates together with the owner-manager of KALK A/S, Mr Rasmus Jorgensen, how to use the Family Business Map to frame a constructive discussion about long-term planning. The Family Business Map is a tool for long-term planning in family firms developed by Professor...

  1. Strategies in intrauterine growth restriction at term

    NARCIS (Netherlands)

    Boers, Kim Esther

    2012-01-01

    To establish consensus and to collect evidence on the best management policy in intrauterine growth restriction (IUGR) at term, the DIGITAT-trial (Disproportionate Intrauterine Growth Intervention Trial At Term) was designed. The aim of the DIGITAT study was to compare the effect of induction of

  2. The Term Processor Generator Kimwitu (Full version)

    NARCIS (Netherlands)

    van Eijk, Peter; Belinfante, Axel; Eertink, Henk; Alblas, H.

    1996-01-01

    The Kimwitu system is a meta-tool that supports the construction of programs (tools) that operate on trees or terms. The system supports open multi-paradigm programming, in that it allows to express each part of an implementation in the most appropriate language. Terms can be implemented in a tool

  3. Short-Term Intercultural Psychotherapy: Ethnographic Inquiry

    Science.gov (United States)

    Seeley, Karen M.

    2004-01-01

    This article examines the challenges specific to short-term intercultural treatments and recently developed approaches to intercultural treatments based on notions of cultural knowledge and cultural competence. The article introduces alternative approaches to short-term intercultural treatments based on ethnographic inquiry adapted for clinical…

  4. Polyakov's quantized string with boundary terms

    International Nuclear Information System (INIS)

    Durhuus, B.; Olesen, P.; Petersen, J.L.

    1981-11-01

    The authors compute the boundary terms needed in Polyakov's method for calculating averages of functionals defined on surfaces. The method used is due to Seeley, who found recursive relations yielding the boundary terms. These relations are solved for a general second order elliptic differential operator. This solution is then applied to Polyakov's problem. (Auth.)

  5. Polyakov's quantized string with boundary terms

    International Nuclear Information System (INIS)

    Durhuus, B.; Olesen, P.; Petersen, J.L.

    1982-01-01

    We compute the boundary terms due to the conformal anomaly which are needed in Polyakov's method of calculating averages of functionals defined on surfaces. The method we use is due to Seeley, who found recursive relations yielding the boundary terms. We solve these relations for a general second-order elliptic differential operator. This solution is then applied to Polyakov's problem. (orig.)

  6. Long-Term Memory and Learning

    Science.gov (United States)

    Crossland, John

    2011-01-01

    The English National Curriculum Programmes of Study emphasise the importance of knowledge, understanding and skills, and teachers are well versed in structuring learning in those terms. Research outcomes into how long-term memory is stored and retrieved provide support for structuring learning in this way. Four further messages are added to the…

  7. 49 CFR 260.9 - Loan terms.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Loan terms. 260.9 Section 260.9 Transportation... TRANSPORTATION REGULATIONS GOVERNING LOANS AND LOAN GUARANTEES UNDER THE RAILROAD REHABILITATION AND IMPROVEMENT FINANCING PROGRAM Overview § 260.9 Loan terms. The maximum repayment period for direct loans and guaranteed...

  8. 13 CFR 500.204 - Loan terms.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Loan terms. 500.204 Section 500.204 Business Credit and Assistance EMERGENCY OIL AND GAS GUARANTEED LOAN BOARD EMERGENCY OIL AND GAS GUARANTEED LOAN PROGRAM Oil and Gas Guaranteed Loans § 500.204 Loan terms. (a) All loans guaranteed under the...

  9. 13 CFR 400.204 - Loan terms.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Loan terms. 400.204 Section 400.204 Business Credit and Assistance EMERGENCY STEEL GUARANTEE LOAN BOARD EMERGENCY STEEL GUARANTEE LOAN PROGRAM Steel Guarantee Loans § 400.204 Loan terms. (a) All loans guaranteed under the Program shall be...

  10. 14 CFR 1300.15 - Loan terms.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Loan terms. 1300.15 Section 1300.15... DISASTER RELIEF-AIR CARRIER GUARANTEE LOAN PROGRAM Minimum Requirements and Application Procedures § 1300.15 Loan terms. (a) A loan guaranteed under the program shall be due and payable in full no later than...

  11. Virtual Models of Long-Term Care

    Science.gov (United States)

    Phenice, Lillian A.; Griffore, Robert J.

    2012-01-01

    Nursing homes, assisted living facilities and home-care organizations, use web sites to describe their services to potential consumers. This virtual ethnographic study developed models representing how potential consumers may understand this information using data from web sites of 69 long-term-care providers. The content of long-term-care web…

  12. 10 CFR 905.31 - Term.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Term. 905.31 Section 905.31 Energy DEPARTMENT OF ENERGY ENERGY PLANNING AND MANAGEMENT PROGRAM Power Marketing Initiative § 905.31 Term. Western will extend resource commitments for 20 years from the date existing contracts expire to existing customers with long...

  13. Many general language dictionaries contain specialized terms

    African Journals Online (AJOL)

    user

    Lexikos 25 (AFRILEX-reeks/series 25: 2015): 246-261 ... attention to the link between dictionary functions, corpora and the data presented in dictionaries, ... technical words) in general language dictionaries is sparse and concerns terms .... civil procedure terms to focus on and in which dictionaries to look, I will go on.

  14. Chiral symmetry in the strong color-electric field in terms of Nambu-Jona-Lasinio model

    International Nuclear Information System (INIS)

    Suganuma, Hideo

    1990-01-01

    We examine the behavior of chiral symmetry in an external gluon field using Nambu-Jona-Lasinio model, which is an effective theory of QCD. The Dyson equation for the dynamical quark mass in the presence of the external color-electric field is obtained. By solving it in the color flux tube inside mesons, chiral symmetry would be restored in the flux tube of mesons and this result supports Chiral Bag picture for mesons. Next we consider the flux tubes formed in the central region for ultra-relativistic heavy-ion collisions, and find the chiral restoration occurs there, so that the current quark mass seems to be suitable in calculating the q-q-bar pair creation rate by the Schwinger formula in the flux-tube picture. (author)

  15. Calculation of source terms for NUREG-1150

    International Nuclear Information System (INIS)

    Breeding, R.J.; Williams, D.C.; Murfin, W.B.; Amos, C.N.; Helton, J.C.

    1987-10-01

    The source terms estimated for NUREG-1150 are generally based on the Source Term Code Package (STCP), but the actual source term calculations used in computing risk are performed by much smaller codes which are specific to each plant. This was done because the method of estimating the uncertainty in risk for NUREG-1150 requires hundreds of source term calculations for each accident sequence. This is clearly impossible with a large, detailed code like the STCP. The small plant-specific codes are based on simple algorithms and utilize adjustable parameters. The values of the parameters appearing in these codes are derived from the available STCP results. To determine the uncertainty in the estimation of the source terms, these parameters were varied as specified by an expert review group. This method was used to account for the uncertainties in the STCP results and the uncertainties in phenomena not considered by the STCP

  16. Long term liquidity analysis of the firm

    Directory of Open Access Journals (Sweden)

    Jaroslav Gonos

    2009-09-01

    Full Text Available Liquidity control is a very difficult and important function. If the business is not liquid in the long term, it is under threatof bankruptcy, and on the other hand surplus of the cash in hand threaten its future efficiency, because the cash in hand is a sourceof only limited profitability. Long term liquidity is related to the ability of the short term and long term liabilities payment. Articleis trying to point out to the monitoring and analyzing of the long term liquidity in the concrete business, in this case the printing industrycompany. Hereby at the end of the article mentioned monitored and analyzed liquidity is evaluated in the five years time period.

  17. Semantiz Structure of the Legal Term

    Directory of Open Access Journals (Sweden)

    Екатерина Владимировна Кулевская

    2016-12-01

    Full Text Available The article examines the semantic structure of the legal term. Nowadays, with the rapid development of cross-cultural communication, people, while pursuing their professional career, learn specific languages, including the language of law, with terms being its important component. Terms can often impede the process of successful cross-cultural communication so teaching cross-cultural communication, according to many researchers, including P. Cranmer and K. Koskinen, is immensely important. The article aims to demonstrate that a legal term, a word or phrase used in legislation, is a generalized name for a legal concept that may lack a precise meaning in practice as it is polysemous. To proof this statement, the semantic structure of the legal term is studied from the cognitive point of view. The key terms (term, frame, lexico-semantic variant of a word, microframe (reference category are defined at the beginning of the article. The article also describes the classification of various semantic structures of terms developed by Prof. Belyayevskaya, based on an analysis of the cognitive foundations of the typology of semantic structures as well as on the classification of meanings. They are homogeneous semantic structures, with different lexico-semantic variants of a polysemous word representing different aspects of one microframe; these structures include monosemous terms, polysemous terms with a homogeneous semantic structure, and terms with the intermediate type of lexemes. Heterogeneous semantic structures are semantic structures, with a lexico-semantic variant of a word representing two or more reference categories rather than one category; these structures are considered to be “classical” polysemy. Two types of such structures are introduced in the article, with examples of the actualization of their lexical meaning in speech being analysed (there were used examples from the British and Russian National corpora; official legal documents and

  18. Food Service Technical Terms. English-Spanish Lexicon.

    Science.gov (United States)

    Shin, Masako T.

    This English-Spanish lexicon presents food service technical terms. The terms are divided into seven categories: basic food items, common baking terms, food cutting terms, general cooking terms, non-English culinary terms, and tools and equipment. Each English word or term is followed by its Spanish equivalent(s). (YLB)

  19. Capturing the semiotic relationship between terms

    Science.gov (United States)

    Hargood, Charlie; Millard, David E.; Weal, Mark J.

    2010-04-01

    Tags describing objects on the web are often treated as facts about a resource, whereas it is quite possible that they represent more subjective observations. Existing methods of term expansion expand terms based on dictionary definitions or statistical information on term occurrence. Here we propose the use of a thematic model for term expansion based on semiotic relationships between terms; this has been shown to improve a system's thematic understanding of content and tags and to tease out the more subjective implications of those tags. Such a system relies on a thematic model that must be made by hand. In this article, we explore a method to capture a semiotic understanding of particular terms using a rule-based guide to authoring a thematic model. Experimentation shows that it is possible to capture valid definitions that can be used for semiotic term expansion but that the guide itself may not be sufficient to support this on a large scale. We argue that whilst the formation of super definitions will mitigate some of these problems, the development of an authoring support tool may be necessary to solve others.

  20. The term origo in Roman epigraphy

    Directory of Open Access Journals (Sweden)

    Rafael GONZÁLEZ FERNÁNDEZ

    2012-03-01

    Full Text Available It is sometimes very difficult to interpret the term origo, since it can refer to different elements such as birth, place of origin, family or tribe. From the Republican period the Romans used to include this type of information in their inscriptions after the mention of the name, although, curiously, they did not employ the term origo itself, but other forms of expression. In this work we suggest that in Roman epigraphy this term was used, from the end of the Second Century and during the first half of the Third Century A. D., mainly in the times of the Severan Dynasty.

  1. Short term memory in echo state networks

    OpenAIRE

    Jaeger, H.

    2001-01-01

    The report investigates the short-term memory capacity of echo state recurrent neural networks. A quantitative measure MC of short-term memory capacity is introduced. The main result is that MC 5 N for networks with linear Output units and i.i.d. input, where N is network size. Conditions under which these maximal memory capacities are realized are described. Several theoretical and practical examples demonstrate how the short-term memory capacities of echo state networks can be exploited for...

  2. Mechanistic facility safety and source term analysis

    International Nuclear Information System (INIS)

    PLYS, M.G.

    1999-01-01

    A PC-based computer program was created for facility safety and source term analysis at Hanford The program has been successfully applied to mechanistic prediction of source terms from chemical reactions in underground storage tanks, hydrogen combustion in double contained receiver tanks, and proccss evaluation including the potential for runaway reactions in spent nuclear fuel processing. Model features include user-defined facility room, flow path geometry, and heat conductors, user-defined non-ideal vapor and aerosol species, pressure- and density-driven gas flows, aerosol transport and deposition, and structure to accommodate facility-specific source terms. Example applications are presented here

  3. Atomic mass formula with linear shell terms

    International Nuclear Information System (INIS)

    Uno, Masahiro; Yamada, Masami; Ando, Yoshihira; Tachibana, Takahiro.

    1981-01-01

    An atomic mass formula is constructed in the form of a sum of gross terms and empirical linear shell terms. Values of the shell parameters are determined after the statistical method of Uno and Yamada, Which is characterized by inclusion of the error inherent in the mass formula. The resulting formula reproduces the input masses with the standard deviation of 393 keV. A prescription is given for estimating errors of calculated masses. The mass formula is compared with recent experimental data of Rb, Cs and Fr isotopes, which are not included in the input data, and also with the constant-shell-term formula of Uno and Yamada. (author)

  4. Implied terms in English and Romanian law

    OpenAIRE

    Stefan Dinu

    2015-01-01

    This study analyses the matter of implied terms from the point of view of both English and Romanian law. First, the introductory section provides a brief overview of implied terms, by defining this class of contractual clauses and by providing their general features. Second, the English law position is analysed, where it is generally recognised that a term may be implied in one of three manners, which are described in turn. An emp hasis is made on the Privy Council’s decision in Attorney G...

  5. Differences in health status between long-term and short-term benzodiazepine users.

    NARCIS (Netherlands)

    Zandstra, S.M.; Furer, J.W.; Lisdonk, E.H. van de; Bor, J.H.J.; Zitman, F.G.; Weel, C. van

    2002-01-01

    BACKGROUND: Despite generally accepted advice to keep treatment short, benzodiazepines are often prescibed for more than six months. Prevention of long-term benzodiazepine use could be facilitated by the utilisation of risk indicators for long-term use. However, the characteristics of long-term

  6. 16 CFR 1611.31 - Terms defined.

    Science.gov (United States)

    2010-01-01

    ..., which is woven, knitted, felted or otherwise produced from any natural or man-made fiber, or substitute... finishes or parchmentized finishes. (m) The definition of terms contained in section 2 of the act shall be...

  7. Dynamic origins of fermionic D -terms

    Science.gov (United States)

    Hudson, Jonathan; Schweitzer, Peter

    2018-03-01

    The D -term is defined through matrix elements of the energy-momentum tensor, similarly to mass and spin, yet this important particle property is experimentally not known any fermion. In this work we show that the D -term of a spin 1/2 fermion is of dynamical origin: it vanishes for a free fermion. This is in pronounced contrast to the bosonic case where already a free spin-0 boson has a non-zero intrinsic D -term. We illustrate in two simple models how interactions generate the D -term of a fermion with an internal structure, the nucleon. All known matter is composed of elementary fermions. This indicates the importance to study this interesting particle property in more detail, which will provide novel insights especially on the structure of the nucleon.

  8. 7 CFR 46.43 - Terms construed.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE MARKETING OF PERISHABLE AGRICULTURAL COMMODITIES REGULATIONS (OTHER THAN RULES OF PRACTICE) UNDER THE PERISHABLE AGRICULTURAL COMMODITIES ACT, 1930 Trade Terms and...

  9. Long term wet spent nuclear fuel storage

    International Nuclear Information System (INIS)

    1987-04-01

    The meeting showed that there is continuing confidence in the use of wet storage for spent nuclear fuel and that long-term wet storage of fuel clad in zirconium alloys can be readily achieved. The importance of maintaining good water chemistry has been identified. The long-term wet storage behaviour of sensitized stainless steel clad fuel involves, as yet, some uncertainties. However, great reliance will be placed on long-term wet storage of spent fuel into the future. The following topics were treated to some extent: Oxidation of the external surface of fuel clad, rod consolidation, radiation protection, optimum methods of treating spent fuel storage water, physical radiation effects, and the behaviour of spent fuel assemblies of long-term wet storage conditions. A number of papers on national experience are included

  10. Language and terms to communicate mathematics

    Directory of Open Access Journals (Sweden)

    Gouthier Daniele

    2002-06-01

    Full Text Available Popularising mathematics requires a preliminary reflection on language and terms, the choice of which results from underlying dynamics. The aim of this article is to start an overall analysis of the conditions influencing this linguistic choice.

  11. Evolution of source term definition and analysis

    International Nuclear Information System (INIS)

    Lutz, R.J. Jr.

    2004-01-01

    The objective of this presentation was to provide an overview of the evolution of accident fission product release analysis methodology and the obtained results; and to provide an overview of the source term implementation analysis in regulatory decisions

  12. Molecular Electronic Terms and Molecular Orbital Configurations.

    Science.gov (United States)

    Mazo, R. M.

    1990-01-01

    Discussed are the molecular electronic terms which can arise from a given electronic configuration. Considered are simple cases, molecular states, direct products, closed shells, and open shells. Two examples are provided. (CW)

  13. Quality assurance terms and definitions - approved 1973

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    Standards for certain terms and their definitions that are important to the uniform understanding of the intent of required quality assurance practices for the construction of nuclear power plants are presented

  14. SOURCE TERMS FOR HLW GLASS CANISTERS

    International Nuclear Information System (INIS)

    J.S. Tang

    2000-01-01

    This calculation is prepared by the Monitored Geologic Repository (MGR) Waste Package Design Section. The objective of this calculation is to determine the source terms that include radionuclide inventory, decay heat, and radiation sources due to gamma rays and neutrons for the high-level radioactive waste (HLW) from the, West Valley Demonstration Project (WVDP), Savannah River Site (SRS), Hanford Site (HS), and Idaho National Engineering and Environmental Laboratory (INEEL). This calculation also determines the source terms of the canister containing the SRS HLW glass and immobilized plutonium. The scope of this calculation is limited to source terms for a time period out to one million years. The results of this calculation may be used to carry out performance assessment of the potential repository and to evaluate radiation environments surrounding the waste packages (WPs). This calculation was performed in accordance with the Development Plan ''Source Terms for HLW Glass Canisters'' (Ref. 7.24)

  15. Implied terms in English and Romanian law

    Directory of Open Access Journals (Sweden)

    Stefan Dinu

    2015-12-01

    Full Text Available This study analyses the matter of implied terms from the point of view of both English and Romanian law. First, the introductory section provides a brief overview of implied terms, by defining this class of contractual clauses and by providing their general features. Second, the English law position is analysed, where it is generally recognised that a term may be implied in one of three manners, which are described in turn. An emp hasis is made on the Privy Council’s decision in Attorney General of Belize v Belize Telecom Ltd and its impact. Third, the Romanian law position is described, the starting point of the discussion being represented by the provisions of Article 1272 of the 2009 Civil Code. Fourth, the study ends by mentioning some points of comparison between the two legal systems in what concerns the approach towards implied terms.

  16. Industrial Foundations as Long-Term Owners

    DEFF Research Database (Denmark)

    Thomsen, Steen; Poulsen, Thomas; Børsting, Christa Winther

    Short-termism has become a serious concern for corporate governance, and this has inspired a search for institutional arrangements to promote long-term decision-making. In this paper, we call attention to long-term ownership by industrial foundations, which is common in Northern Europe but little...... known in the rest of the world. We use a unique Danish data set to document that industrial foundations are long-term owners that practice long-term governance. We show that foundation ownership is highly stable compared to other ownership structures. Foundation-owned companies replace managers less...... frequently. They have conservative capital structures with low financial leverage. They score higher on an index of long-termism in finance, investment, and employment. They survive longer. Overall, our paper supports the hypothesis that corporate time horizons are influenced by ownership structures...

  17. Definitions of Health Terms: General Health

    Science.gov (United States)

    ... needs to stay healthy. You can start by learning these general health terms. Find more definitions on Fitness | General Health | Minerals | Nutrition | Vitamins Basal Body Temperature Basal body temperature is your temperature at rest ...

  18. Coping with PH over the Long Term

    Science.gov (United States)

    ... a job, a volunteer commitment, or even a hobby can take a toll on long-term survivors ... people find solace in meditation, faith, humor, writing, hobbies and more. Find an outlet that you enjoy ...

  19. Common SIDS and SUID Terms and Definitions

    Science.gov (United States)

    ... media links Common SIDS and SUID Terms and Definitions Page Content Health care providers and others may ... NICHD Home Accessibility NICHD Contact Disclaimer NICHD Accounts: Facebook Twitter Pinterest YouTube NIH...Turning Discovery Into Health ® ...

  20. Perinatal brain damage : The term infant

    NARCIS (Netherlands)

    Hagberg, Henrik; David Edwards, A.; Groenendaal, Floris

    2016-01-01

    Perinatal brain injury at term is common and often manifests with neonatal encephalopathy including seizures. The most common aetiologies are hypoxic–ischaemic encephalopathy, intracranial haemorrhage and neonatal stroke. Besides clinical and biochemical assessment the diagnostic evaluation rely

  1. Long term effects of radiation in man

    International Nuclear Information System (INIS)

    Tso Chih Ping; Idris Besar

    1984-01-01

    An overview of the long term effects of radiation in man is presented, categorizing into somatic effects, genetic effects and teratogenic effects, and including an indication of the problems that arise in their determination. (author)

  2. Entanglement temperature with Gauss–Bonnet term

    Directory of Open Access Journals (Sweden)

    Shesansu Sekhar Pal

    2015-09-01

    Full Text Available We compute the entanglement temperature using the first law-like of thermodynamics, ΔE=TentΔSEE, up to Gauss–Bonnet term in the Jacobson–Myers entropy functional in any arbitrary spacetime dimension. The computation is done when the entangling region is the geometry of a slab. We also show that such a Gauss–Bonnet term, which becomes a total derivative, when the co-dimension two hypersurface is four dimensional, does not contribute to the finite term in the entanglement entropy. We observe that the Weyl-squared term does not contribute to the entanglement entropy. It is important to note that the calculations are performed when the entangling region is very small and the energy is calculated using the normal Hamiltonian.

  3. A Tactical Emergency Response Management System (Terms ...

    African Journals Online (AJOL)

    2013-03-01

    Mar 1, 2013 ... information is a result of collaboration between accident response personnel. ... Tactical Emergency Response Management System (TERMS) which unifies all these different ... purpose of handling crisis and emergency.

  4. Fractional Regularization Term for Variational Image Registration

    Directory of Open Access Journals (Sweden)

    Rafael Verdú-Monedero

    2009-01-01

    Full Text Available Image registration is a widely used task of image analysis with applications in many fields. Its classical formulation and current improvements are given in the spatial domain. In this paper a regularization term based on fractional order derivatives is formulated. This term is defined and implemented in the frequency domain by translating the energy functional into the frequency domain and obtaining the Euler-Lagrange equations which minimize it. The new regularization term leads to a simple formulation and design, being applicable to higher dimensions by using the corresponding multidimensional Fourier transform. The proposed regularization term allows for a real gradual transition from a diffusion registration to a curvature registration which is best suited to some applications and it is not possible in the spatial domain. Results with 3D actual images show the validity of this approach.

  5. Long Term Care Minimum Data Set (MDS)

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Long-Term Care Minimum Data Set (MDS) is a standardized, primary screening and assessment tool of health status that forms the foundation of the comprehensive...

  6. Colour terms in the interior design process

    OpenAIRE

    Attiah, DY; Cheung, TLV; Westland, S; Bromilow, D

    2015-01-01

    Colour is a very important topic that interior designers need to consider. Considerable research has been conducted in the area of colour application in interior design; in this study we are concerned with colour terms in interior design, mainly the terms designers use and know about. Fifteen interior designers with varied professional backgrounds, but based in the Middle East (Saudi Arabia, Dubai, Bahrain, Lebanon, Egypt, and Turkey), were interviewed. Previously we reported that fourteen ou...

  7. Definition of terms for practical superconductors

    International Nuclear Information System (INIS)

    Fickett, F.R.; Kaplan, S.B.; Powell, R.L.; Radebaugh, R.; Clark, A.F.

    1980-01-01

    The definitions of terms used in describing the phenomenology and measurement practices of practical superconductive materials are proposed. The definitions cover the subject categories of: 1, fundamental states and flux phenomena, 2, critical parameters, 3, fabrication, stabilization, and transient losses, and 4, Josephson phenomena. It is intended that these terms will become the basis for development of standard measurement practices and responses are invited. (author)

  8. Definitions of terms for practical superconductors

    International Nuclear Information System (INIS)

    Read, D.T.; Ekin, J.W.; Powell, R.L.; Clark, A.F.

    1979-01-01

    The definitions of terms used in describing the phenomenology and measurement practices of practical superconductive materials are proposed. The definitions cover the subject categories of: (1) fundamental states and flux phenomena; (2) critical parameters; (3) fabrication, stabilization, and transient losses; and (4) Josephson phenomena. It is intended that these terms will become the basis for the development of standard measurement practices and responses are invited. (author)

  9. Definitions of terms for practical superconductors

    International Nuclear Information System (INIS)

    Powell, R.; Clark, A.F.

    1977-01-01

    The definitions of terms used in describing the phenomenology and measurement practices of practical superconductive materials are proposed. The definitions cover the subject categories of: (1) fundamental states and flux phenomena, (2) critical parameters, (3) fabrication, stabilization, and transient losses, and (4) Josephson phenomena. It is intended that these terms become the basis for the development of standard measurement practices and responses are invited. (author)

  10. Petroleum term markets and OPEC producers countries

    International Nuclear Information System (INIS)

    Bensarsa, F.

    1994-01-01

    The situation of petroleum producers countries in front of term markets is described. With an economics liberalization, policy configuration changing the energetic balance (increasing of american imports, of asiatic demand and developing countries; decreasing of russian production), a more efficient technology, a right management of energetic resources with energy economy, renewable energies and non polluting energies, it is difficult for producers countries to resist at the pressure of financing tools, more and more modern and efficient as they are term markets

  11. Search, Dealers, and the Terms of Trade

    OpenAIRE

    Gabriele Camera

    2001-01-01

    I study a search theoretic model with pairwise meetings where dealers arise endogenously. The extent of intermediation depends on its cost, trade frictions, and the dealers' ability to negociate favorable terms of trade. Under Nash bargaining, there is a unique equilibrium where dealers buy and hold the low-storage-cost good and, depending on their relative bargaining power, resell it at a premium or a discount. The distribution of the terms of trade is non-degenerate unless storage cost and ...

  12. A glossary of terms for fast reactors

    International Nuclear Information System (INIS)

    Wheeler, R.C.

    1979-04-01

    The glossary aims to provide definitions of technical terms likely to be used in a fast reactor enquiry and to encourage the use of the same set of consistent terms in any documents intended for such an inquiry. In some cases definitions are formulated in the limited context of LMFBRS rather than applying to all types of reactors. A brief guide is presented to the different reactor types. (author)

  13. Short-term Memory of Deep RNN

    OpenAIRE

    Gallicchio, Claudio

    2018-01-01

    The extension of deep learning towards temporal data processing is gaining an increasing research interest. In this paper we investigate the properties of state dynamics developed in successive levels of deep recurrent neural networks (RNNs) in terms of short-term memory abilities. Our results reveal interesting insights that shed light on the nature of layering as a factor of RNN design. Noticeably, higher layers in a hierarchically organized RNN architecture results to be inherently biased ...

  14. Nuclear or radiology: which term to use?

    International Nuclear Information System (INIS)

    2005-01-01

    This document brings information and definition to help the public in the distinction between the two terms: nuclear and radiologic. What means the words nuclear and radiologic in the physics and common languages? In which situation an accidental or malevolent event can be called nuclear or radiologic? By which technic and for which use is concerned the radiology? It concludes by recommendation for the choice of one or the other term. (A.L.B.)

  15. Timber joints under long-term loading

    DEFF Research Database (Denmark)

    Feldborg, T.; Johansen, M.

    This report describes tests and results from stiffness and strength testing of splice joints under long-term loading. During two years of loading the spicimens were exposed to cyclically changing relative humidity. After the loading period the specimens were short-term tested. The connectors were...... integral nail-plates and nailed steel and plywood gussets. The report is intended for designers and researchers in timber engineering....

  16. Fast Weight Long Short-Term Memory

    OpenAIRE

    Keller, T. Anderson; Sridhar, Sharath Nittur; Wang, Xin

    2018-01-01

    Associative memory using fast weights is a short-term memory mechanism that substantially improves the memory capacity and time scale of recurrent neural networks (RNNs). As recent studies introduced fast weights only to regular RNNs, it is unknown whether fast weight memory is beneficial to gated RNNs. In this work, we report a significant synergy between long short-term memory (LSTM) networks and fast weight associative memories. We show that this combination, in learning associative retrie...

  17. Modular invariance, chiral anomalies and contact terms

    International Nuclear Information System (INIS)

    Kutasov, D.

    1988-03-01

    The chiral anomaly in heterotic strings with full and partial modular invariance in D=2n+2 dimensions is calculated. The boundary terms which were present in previous calculations are shown to be cancelled in the modular invariant case by contact terms, which can be obtained by an appropriate analytic continuation. The relation to the low energy field theory is explained. In theories with partial modular invariance, an expression for the anomaly is obtained and shown to be non zero in general. (author)

  18. What are the differences between long-term, short-term, and working memory?

    OpenAIRE

    Cowan, Nelson

    2008-01-01

    In the recent literature there has been considerable confusion about the three types of memory: long-term, short-term, and working memory. This chapter strives to reduce that confusion and makes up-to-date assessments of these types of memory. Long- and short-term memory could differ in two fundamental ways, with only short-term memory demonstrating (1) temporal decay and (2) chunk capacity limits. Both properties of short-term memory are still controversial but the current literature is rath...

  19. Term Croatian considered in russian context

    Directory of Open Access Journals (Sweden)

    Željka Čelić

    2008-01-01

    Full Text Available Term Croatian is considered in Russian context, i. e. context of Russian scientific material (which is comparable to the unwritten situation in universities. Russian scientific texts connect term Croatian, almost without an exception, with the term Serbian in words such as Serbo-Croatian. This point of view is politically approved in the period untill 1990’s, but it exists in the 21st century’s scientific material. The nature of the problem lays, at the same time, in politics, language and society; thus, the question is: what is the reason of such a context in which Croatian language is placed now? There are no arguments for it, especially if it is for Slovak language politically based and language approved to be an entity – in comparison to the Czech language; for Ukrainian (once Littlerussian – at least in principle, in comparison to the Russian, or, more convincable, Belorussian to Russian (the standard Belorussian language exists from 1905. The term Croatian is independently, even in new books, connected with terms of soil, state, nation, but not language. And though today, because of political reasons, exists an awareness of Croatian language without its Serbian mirror reflexion, the term Serbo-Croatian stays. Thus, this paper looks through the history concerning Croatian language in 19, 20 and 21st century’s Russian philology, including Juraj Križanić and Vatroslav Jagić – innovators of the Croatian word in Russia.

  20. A least squares approach for efficient and reliable short-term versus long-term optimization

    DEFF Research Database (Denmark)

    Christiansen, Lasse Hjuler; Capolei, Andrea; Jørgensen, John Bagterp

    2017-01-01

    The uncertainties related to long-term forecasts of oil prices impose significant financial risk on ventures of oil production. To minimize risk, oil companies are inclined to maximize profit over short-term horizons ranging from months to a few years. In contrast, conventional production...... optimization maximizes long-term profits over horizons that span more than a decade. To address this challenge, the oil literature has introduced short-term versus long-term optimization. Ideally, this problem is solved by a posteriori multi-objective optimization methods that generate an approximation...... the balance between the objectives, leaving an unfulfilled potential to increase profits. To promote efficient and reliable short-term versus long-term optimization, this paper introduces a natural way to characterize desirable Pareto points and proposes a novel least squares (LS) method. Unlike hierarchical...

  1. Very long-term sequelae of craniopharyngioma.

    Science.gov (United States)

    Wijnen, Mark; van den Heuvel-Eibrink, Marry M; Janssen, Joseph A M J L; Catsman-Berrevoets, Coriene E; Michiels, Erna M C; van Veelen-Vincent, Marie-Lise C; Dallenga, Alof H G; van den Berge, J Herbert; van Rij, Carolien M; van der Lely, Aart-Jan; Neggers, Sebastian J C M M

    2017-06-01

    Studies investigating long-term health conditions in patients with craniopharyngioma are limited by short follow-up durations and generally do not compare long-term health effects according to initial craniopharyngioma treatment approach. In addition, studies comparing long-term health conditions between patients with childhood- and adult-onset craniopharyngioma report conflicting results. The objective of this study was to analyse a full spectrum of long-term health effects in patients with craniopharyngioma according to initial treatment approach and age group at craniopharyngioma presentation. Cross-sectional study based on retrospective data. We studied a single-centre cohort of 128 patients with craniopharyngioma treated from 1980 onwards (63 patients with childhood-onset disease). Median follow-up since craniopharyngioma presentation was 13 years (interquartile range: 5-23 years). Initial craniopharyngioma treatment approaches included gross total resection ( n  = 25), subtotal resection without radiotherapy ( n  = 44), subtotal resection with radiotherapy ( n  = 25), cyst aspiration without radiotherapy ( n  = 8), and 90 Yttrium brachytherapy ( n  = 21). Pituitary hormone deficiencies (98%), visual disturbances (75%) and obesity (56%) were the most common long-term health conditions observed. Different initial craniopharyngioma treatment approaches resulted in similar long-term health effects. Patients with childhood-onset craniopharyngioma experienced significantly more growth hormone deficiency, diabetes insipidus, panhypopituitarism, morbid obesity, epilepsy and psychiatric conditions compared with patients with adult-onset disease. Recurrence-/progression-free survival was significantly lower after initial craniopharyngioma treatment with cyst aspiration compared with other therapeutic approaches. Survival was similar between patients with childhood- and adult-onset craniopharyngioma. Long-term health conditions were comparable after

  2. Long-term associative learning predicts verbal short-term memory performance.

    Science.gov (United States)

    Jones, Gary; Macken, Bill

    2018-02-01

    Studies using tests such as digit span and nonword repetition have implicated short-term memory across a range of developmental domains. Such tests ostensibly assess specialized processes for the short-term manipulation and maintenance of information that are often argued to enable long-term learning. However, there is considerable evidence for an influence of long-term linguistic learning on performance in short-term memory tasks that brings into question the role of a specialized short-term memory system separate from long-term knowledge. Using natural language corpora, we show experimentally and computationally that performance on three widely used measures of short-term memory (digit span, nonword repetition, and sentence recall) can be predicted from simple associative learning operating on the linguistic environment to which a typical child may have been exposed. The findings support the broad view that short-term verbal memory performance reflects the application of long-term language knowledge to the experimental setting.

  3. What are the differences between long-term, short-term, and working memory?

    Science.gov (United States)

    Cowan, Nelson

    2008-01-01

    In the recent literature there has been considerable confusion about the three types of memory: long-term, short-term, and working memory. This chapter strives to reduce that confusion and makes up-to-date assessments of these types of memory. Long- and short-term memory could differ in two fundamental ways, with only short-term memory demonstrating (1) temporal decay and (2) chunk capacity limits. Both properties of short-term memory are still controversial but the current literature is rather encouraging regarding the existence of both decay and capacity limits. Working memory has been conceived and defined in three different, slightly discrepant ways: as short-term memory applied to cognitive tasks, as a multi-component system that holds and manipulates information in short-term memory, and as the use of attention to manage short-term memory. Regardless of the definition, there are some measures of memory in the short term that seem routine and do not correlate well with cognitive aptitudes and other measures (those usually identified with the term "working memory") that seem more attention demanding and do correlate well with these aptitudes. The evidence is evaluated and placed within a theoretical framework depicted in Fig. 1.

  4. Some practical implications of source term reassessment

    International Nuclear Information System (INIS)

    1988-03-01

    This report provides a brief summary of the current knowledge of severe accident source terms and suggests how this knowledge might be applied to a number of specific aspects of reactor safety. In preparing the report, consideration has been restricted to source term issues relating to light water reactors (LWRs). Consideration has also generally been restricted to the consequences of hypothetical severe accidents rather than their probability of occurrence, although it is recognized that, in the practical application of source term research, it is necessary to take account of probability as well as consequences. The specific areas identified were as follows: Exploration of the new insights that are available into the management of severe accidents; Investigating the impact of source term research on emergency planning and response; Assessing the possibilities which exist in present reactor designs for preventing or mitigating the consequences of severe accidents and how these might be used effectively; Exploring the need for backfitting and assessing the implications of source term research for future designs; and Improving the quantification of the radiological consequences of hypothetical severe accidents for probabilistic safety assessments (PSAs) and informing the public about the realistic risks associated with nuclear power plants. 7 refs

  5. Short-term memory across eye blinks.

    Science.gov (United States)

    Irwin, David E

    2014-01-01

    The effect of eye blinks on short-term memory was examined in two experiments. On each trial, participants viewed an initial display of coloured, oriented lines, then after a retention interval they viewed a test display that was either identical or different by one feature. Participants kept their eyes open throughout the retention interval on some blocks of trials, whereas on others they made a single eye blink. Accuracy was measured as a function of the number of items in the display to determine the capacity of short-term memory on blink and no-blink trials. In separate blocks of trials participants were instructed to remember colour only, orientation only, or both colour and orientation. Eye blinks reduced short-term memory capacity by approximately 0.6-0.8 items for both feature and conjunction stimuli. A third, control, experiment showed that a button press during the retention interval had no effect on short-term memory capacity, indicating that the effect of an eye blink was not due to general motoric dual-task interference. Eye blinks might instead reduce short-term memory capacity by interfering with attention-based rehearsal processes.

  6. Long-term prisoner in prison isolation

    Directory of Open Access Journals (Sweden)

    Karolina Grudzińska

    2013-06-01

    Full Text Available Long-term prisoner belongs to a particular category of people who are imprisoned in prisons. On the one hand in this group are often heavily demoralized people who committed the most serious crimes, on the other hand it is a group of prisoners, who should be well thought out and programmed the impact of rehabilitation. The situation of man trapped for years poses in a complicated situation not only the prisoners, but also the entire prison staff. They have to take care of the fact that the prison isolation did not cause the state in which convicts form itself in learned helplessness and lack of skills for self-planning and decision-making. In addition, planning the rehabilitation impact of long-term prisoners should not be forgotten that these prisoners in the short or the long term will return to the libertarian environment therefore, should prevent any negative effects of long-term imprisonment. This article presents the main issues related to the execution of imprisonment against long-term prisoners. It is an attempt to systematize the knowledge of this category of people living in prison isolation.

  7. New Computer Terms in Bloggers’ Language

    Directory of Open Access Journals (Sweden)

    Vilija Celiešienė

    2012-06-01

    Full Text Available The article presents an analysis of new words in computer terminology that make their way to blogs and analyzes how the official neologisms and computer terms, especially the equivalents to barbarisms, are employed in everyday use. The article also discusses the ways of including the new computer terms into texts. The blogs on topics of information technology are the objects of the research. The analysis of the aforementioned blogs allowed highlighting certain trends in the use of new computer terms. An observation was made that even though the authors of the blogs could freely choose their writing style, they were not bound by the standards of literary language. Thus, their language was full of non-standard vocabulary; however, self-control regarding the language used could still be noticed. An interest in novelties of computer terminology and the tendency to accept some of the suggested new Lithuanian and loaned computer terms were noticed. When using the new words the bloggers frequently employed specific graphical elements and (or comments. The graphical elements were often chosen by bloggers to express their feelings of doubt regarding the suitability of the use of the suggested loanword. Attempting to explain the meaning of the new word to the readers the bloggers tended to post comments about the new computer terms.

  8. The {mu} term and neutrino masses

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mu-Chun [California Univ., Irvine, CA (United States). Dept. of Physics and Astronomy; Ratz, Michael; Staudt, Christian [Technische Univ. Muenchen, Garching (Germany). Physik-Department; Vaudrevange, Patrick K.S. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2012-06-15

    The well-known Giudice-Masiero mechanism explains the presence of a {mu} term of the order of the gravitino mass, but does not explain why the holomorphic mass term is absent in the superpotential. We discuss anomaly-free discrete symmetries which are both compatible with SU(5) unification of matter and the Giudice-Masiero mechanism, i.e. forbid the {mu} term in the superpotential while allowing the necessary Kaehler potential term. We find that these are Z{sup R}{sub M} symmetries with the following properties: (i) M is a multiple of four; (ii) the Higgs bilinear H{sub u} H{sub d} transforms trivially; (iii) the superspace coordinate {theta} has charge M/4 and, accordingly, the superpotential has charge M/2; (iv) dimension five proton decay operators are automatically absent. All Z{sup R}{sub M} symmetries are anomaly-free due to a non-trivial transformation of a Green-Schwarz axion, and, as a consequence, a holomorphic {mu} term appears at the non-perturbative level. There is a unique symmetry that is consistent with the Weinberg operator while there is a class of Z{sup R}{sub M} symmetries which explain suppressed Dirac neutrino masses.

  9. The μ term and neutrino masses

    International Nuclear Information System (INIS)

    Chen, Mu-Chun

    2012-06-01

    The well-known Giudice-Masiero mechanism explains the presence of a μ term of the order of the gravitino mass, but does not explain why the holomorphic mass term is absent in the superpotential. We discuss anomaly-free discrete symmetries which are both compatible with SU(5) unification of matter and the Giudice-Masiero mechanism, i.e. forbid the μ term in the superpotential while allowing the necessary Kaehler potential term. We find that these are Z R M symmetries with the following properties: (i) M is a multiple of four; (ii) the Higgs bilinear H u H d transforms trivially; (iii) the superspace coordinate θ has charge M/4 and, accordingly, the superpotential has charge M/2; (iv) dimension five proton decay operators are automatically absent. All Z R M symmetries are anomaly-free due to a non-trivial transformation of a Green-Schwarz axion, and, as a consequence, a holomorphic μ term appears at the non-perturbative level. There is a unique symmetry that is consistent with the Weinberg operator while there is a class of Z R M symmetries which explain suppressed Dirac neutrino masses.

  10. Long-Term Prognosis of Plantar Fasciitis

    DEFF Research Database (Denmark)

    Hansen, Liselotte; Krogh, Thøger Persson; Ellingsen, Torkell

    2018-01-01

    , exercise-induced symptoms, bilateral heel pain, fascia thickness, and presence of a heel spur) could predict long-term outcomes, (3) to assess the long-term ultrasound (US) development in the fascia, and (4) to assess whether US-guided corticosteroid injections induce atrophy of the heel fat pad. Study....... The risk was significantly greater for women (P heel...... regardless of symptoms and had no impact on prognosis, and neither did the presence of a heel spur. Only 24% of asymptomatic patients had a normal fascia on US at long-term follow-up. A US-guided corticosteroid injection did not cause atrophy of the heel fat pad. Our observational study did not allow us...

  11. Baby Skyrme models without a potential term

    Science.gov (United States)

    Ashcroft, Jennifer; Haberichter, Mareike; Krusch, Steffen

    2015-05-01

    We develop a one-parameter family of static baby Skyrme models that do not require a potential term to admit topological solitons. This is a novel property as the standard baby Skyrme model must contain a potential term in order to have stable soliton solutions, though the Skyrme model does not require this. Our new models satisfy an energy bound that is linear in terms of the topological charge and can be saturated in an extreme limit. They also satisfy a virial theorem that is shared by the Skyrme model. We calculate the solitons of our new models numerically and observe that their form depends significantly on the choice of parameter. In one extreme, we find compactons while at the other there is a scale invariant model in which solitons can be obtained exactly as solutions to a Bogomolny equation. We provide an initial investigation into these solitons and compare them with the baby Skyrmions of other models.

  12. Nuclear Targeting Terms for Engineers and Scientists

    Energy Technology Data Exchange (ETDEWEB)

    St Ledger, John W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-01

    The Department of Defense has a methodology for targeting nuclear weapons, and a jargon that is used to communicate between the analysts, planners, aircrews, and missile crews. The typical engineer or scientist in the Department of Energy may not have been exposed to the nuclear weapons targeting terms and methods. This report provides an introduction to the terms and methodologies used for nuclear targeting. Its purpose is to prepare engineers and scientists to participate in wargames, exercises, and discussions with the Department of Defense. Terms such as Circular Error Probable, probability of hit and damage, damage expectancy, and the physical vulnerability system are discussed. Methods for compounding damage from multiple weapons applied to one target are presented.

  13. Instantons, fermions and Chern-Simons terms

    International Nuclear Information System (INIS)

    Collie, Benjamin; Tong, David

    2008-01-01

    In five spacetime dimensions, instantons are finite energy, solitonic particles. We describe the dynamics of these objects in the presence of a Chern-Simons interaction. For U(N) instantons, we show that the 5d Chern-Simons term induces a corresponding Chern-Simons term in the ADHM quantum mechanics. For SU(N) instantons, we provide a description in terms of geodesic motion on the instanton moduli space, modified by the presence of a magnetic field. We show that this magnetic field is equal to the first Chern character of an index bundle. All of these results are derived by a simple method which follows the fate of zero modes as fermions are introduced, made heavy, and subsequently integrated out.

  14. NOTION VS TERM: LINGUO-SEMIOTIC ASPECT

    Directory of Open Access Journals (Sweden)

    Tatyana Viktorovna Tyurneva

    2017-03-01

    Full Text Available Purpose. As the title implies the article describes linguo-semiotic analysis of the notion and term suggesting differentiation of the mental entities based on discourse community classification. The paper is concerned with peculiarities of notion and term interpretation illustrating their different nature as well as sphere of usage. Methods and methodology. To achieve the objectives the following methods were used: interpretive method, method of speech act analysis, definitional analysis. Results. The article presents a study of semiotic entities in relation to certain discursive practices that allows us to differentiate the term and concept. Applications. Results of the study can be used in teaching such university courses as intercultural communication, discourse analysis and interpretation of the text.

  15. Prediction of long-term creep curves

    International Nuclear Information System (INIS)

    Oikawa, Hiroshi; Maruyama, Kouichi

    1992-01-01

    This paper aims at discussing how to predict long-term irradiation enhanced creep properties from short-term tests. The predictive method based on the θ concept was examined by using creep data of ferritic steels. The method was successful in predicting creep curves including the tertiary creep stage as well as rupture lifetimes. Some material constants involved in the method are insensitive to the irradiation environment, and their values obtained in thermal creep are applicable to irradiation enhanced creep. The creep mechanisms of most engineering materials definitely change at the athermal yield stress in the non-creep regime. One should be aware that short-term tests must be carried out at stresses lower than the athermal yield stress in order to predict the creep behavior of structural components correctly. (orig.)

  16. Adaptation to climate change. Key terms

    International Nuclear Information System (INIS)

    Levina, E.; Tirpak, D.

    2006-05-01

    Adaptation has become an important issue in international and domestic discussions on climate change. Numerous terms and concepts have come into common usage as a result of IPCC reports, discussions in the context of the UNFCCC and dialogs by the climate community at large. This paper examines the key adaptation terms and concepts used by the climate change community and other institutions. Conflicts and contradictions are noted with the aim of sensitizing different bodies to the differences, but particularly the Parties to the Convention and experts participating in the IPCC. Given the need to promote a common understanding among various stakeholders and the potential financial implications of various definitions, it appears important for the IPCC and the UNFCCC to work toward common definitions, at least for a core set of terms and concepts

  17. Holographic entanglement for Chern-Simons terms

    International Nuclear Information System (INIS)

    Azeyanagi, Tatsuo; Loganayagam, R.; Ng, Gim Seng

    2017-01-01

    We derive the holographic entanglement entropy contribution from pure and mixed gravitational Chern-Simons(CS) terms in AdS 2k+1 . This is done through two different methods: first, by a direct evaluation of CS action in a holographic replica geometry and second by a descent of Dong’s derivation applied to the corresponding anomaly polynomial. In lower dimensions (k=1,2), the formula coincides with the Tachikawa formula for black hole entropy from gravitational CS terms. New extrinsic curvature corrections appear for k≥3: we give explicit and concise expressions for the two pure gravitational CS terms in AdS 7 and present various consistency checks, including agreements with the black hole entropy formula when evaluated at the bifurcation surface.

  18. Holographic entanglement for Chern-Simons terms

    Energy Technology Data Exchange (ETDEWEB)

    Azeyanagi, Tatsuo [Département de Physique, Ecole Normale Supérieure, CNRS,24 rue Lhomond, 75005 Paris (France); Loganayagam, R. [School of Natural Sciences, Institute for Advanced Study,Princeton, NJ 08540 (United States); Ng, Gim Seng [Department of Physics, McGill University,Montréal, QC H3A 2T8 (Canada)

    2017-02-01

    We derive the holographic entanglement entropy contribution from pure and mixed gravitational Chern-Simons(CS) terms in AdS{sub 2k+1}. This is done through two different methods: first, by a direct evaluation of CS action in a holographic replica geometry and second by a descent of Dong’s derivation applied to the corresponding anomaly polynomial. In lower dimensions (k=1,2), the formula coincides with the Tachikawa formula for black hole entropy from gravitational CS terms. New extrinsic curvature corrections appear for k≥3: we give explicit and concise expressions for the two pure gravitational CS terms in AdS{sub 7} and present various consistency checks, including agreements with the black hole entropy formula when evaluated at the bifurcation surface.

  19. Holographic entanglement for Chern-Simons terms

    Science.gov (United States)

    Azeyanagi, Tatsuo; Loganayagam, R.; Ng, Gim Seng

    2017-02-01

    We derive the holographic entanglement entropy contribution from pure and mixed gravitational Chern-Simons(CS) terms in AdS2 k+1. This is done through two different methods: first, by a direct evaluation of CS action in a holographic replica geometry and second by a descent of Dong's derivation applied to the corresponding anomaly polynomial. In lower dimensions ( k = 1 , 2), the formula coincides with the Tachikawa formula for black hole entropy from gravitational CS terms. New extrinsic curvature corrections appear for k ≥ 3: we give explicit and concise expressions for the two pure gravitational CS terms in AdS7 and present various consistency checks, including agreements with the black hole entropy formula when evaluated at the bifurcation surface.

  20. Long-term dependence in exchange rates

    Directory of Open Access Journals (Sweden)

    A. Karytinos

    2000-01-01

    Full Text Available The extent to which exchange rates of four major currencies against the Greek Drachma exhibit long-term dependence is investigated using a R/S analysis testing framework. We show that both classic R/S analysis and the modified R/S statistic if enhanced by bootstrapping techniques can be proven very reliable tools to this end. Our findings support persistence and long-term dependence with non-periodic cycles for the Deutsche Mark and the French Franc series. In addition a noisy chaos explanation is favored over fractional Brownian motion. On the contrary, the US Dollar and British Pound were found to exhibit a much more random behavior and lack of any long-term structure.

  1. Terms of trade and Russian economic development

    Directory of Open Access Journals (Sweden)

    Georgy Idrisov

    2016-09-01

    Full Text Available The paper discusses economic development trends in Russia in late 2014 and 2015 and reviews the basic mechanisms of how changes in the terms of trade affect the economic development of countries from a historical perspective and with a particular focus on those changes in the Russian economy that occurred in late 2014 and 2015. The authors demonstrate that structural reforms aimed at diversification of production and exports are necessary for sustainable economic development, for social stability and for reducing the impact of variability in the terms of trade on the Russian economy. During periods of instability in the government agenda's measures for the real and financial sectors, it is necessary not only to compensate economic agents losses caused by changes in the terms of trade but also to improve the economic structure and to develop and enhance the stability of the financial markets.

  2. Long-term contracts vs. short-term trade of natural gas - a European perspective

    International Nuclear Information System (INIS)

    Neuhoff, Karsten; Hirschhausen, Christian von

    2005-01-01

    This paper analyses the economics of long-term gas contracts under changing institutional conditions, mainly gas sector liberalisation. The paper is motivated by the increasingly tense debate in continental Europe, UK and the US on the security of long-term gas supply. We discuss the main issues regarding long-term contracts, i.e. the changing role of the flexibility clause, the effect of abandoning the destination clause, and the strategic behaviour of producers between long-term sales and spot-sales. The literature suggests consumers and producers benefit from risk hedging through long-term contracts. Furthermore long-term contracts may reduce exercise of market power. Our analysis adds an additional benefit if the long-run demand elasticity is significantly lower than the short-run elasticity, both strategic producers and consumers benefit from lower prices and larger market volume. Some policy implications of the findings are also discussed. (Author)

  3. Long-term follow-up study and long-term care of childhood cancer survivors

    Directory of Open Access Journals (Sweden)

    Hyeon Jin Park

    2010-04-01

    Full Text Available The number of long-term survivors is increasing in the western countries due to remarkable improvements in the treatment of childhood cancer. The long-term complications of childhood cancer survivors in these countries were brought to light by the childhood cancer survivor studies. In Korea, the 5-year survival rate of childhood cancer patients is approaching 70%; therefore, it is extremely important to undertake similar long-term follow-up studies and comprehensive long-term care for our population. On the basis of the experiences of childhood cancer survivorship care of the western countries and the current Korean status of childhood cancer survivors, long-term follow-up study and long-term care systems need to be established in Korea in the near future. This system might contribute to the improvement of the quality of life of childhood cancer survivors through effective intervention strategies.

  4. Anatomy of FD-term hybrid inflation

    International Nuclear Information System (INIS)

    Garbrecht, Bjoern; Pallis, Constantinos; Pilaftsis, Apostolos

    2006-01-01

    We analyze the cosmological implications of F-term hybrid inflation with a subdominant Fayet-Iliopoulos D-term whose presence explicitly breaks a D-parity in the inflaton-waterfall sector. This scenario of inflation, which is called F D -term hybrid model for brevity, can naturally predict lepton number violation at the electroweak scale, by tying the μ-parameter of the MSSM to an SO(3)-symmetric Majorana mass m N , via the vacuum expectation value of the inflaton field. We show how a negative Hubble-induced mass term in a next-to-minimal extension of supergravity helps to accommodate the present CMB data and considerably weaken the strict constraints on the theoretical parameters, resulting from cosmic string effects on the power spectrum P R . The usual gravitino overabundance constraint may be significantly relaxed in this model, once the enormous entropy release from the late decays of the ultraheavy waterfall gauge particles is properly considered. As the Universe enters a second thermalization phase involving a very low reheat temperature, which might be as low as about 0.3 TeV, thermal electroweak-scale resonant leptogenesis provides a viable mechanism for successful baryogenesis, while thermal right-handed sneutrinos emerge as new possible candidates for solving the cold dark matter problem. In addition, we discuss grand unified theory realizations of F D -term hybrid inflation devoid of cosmic strings and monopoles, based on the complete breaking of an SU(2) X subgroup. The F D -term hybrid model offers rich particle-physics phenomenology, which could be probed at high-energy colliders, as well as in low-energy experiments of lepton flavour or number violation

  5. Short-term LNG-markets

    International Nuclear Information System (INIS)

    Eldegard, Tom; Lund, Arne-Christian; Miltersen, Kristian; Rud, Linda

    2005-01-01

    The global Liquefied Natural Gas (LNG) industry has experienced substantial growth in the past decades. In the traditional trade patterns of LNG the product has typically been handled within a dedicated chain of plants and vessels fully committed by long term contracts or common ownership, providing risk sharing of large investments in a non-liquid market. Increasing gas prices and substantial cost reductions in all parts of the LNG chain have made LNG projects viable even if only part of the capacity is secured by long-term contracts, opening for more flexible trade of the remainder. Increasing gas demand, especially in power generation, combined with cost reductions in the cost of LNG terminals, open new markets for LNG. For the LNG supplier, the flexibility of shifting volumes between regions represents an additional value. International trade in LNG has been increasing, now accounting for more than one fifth of the world's cross-border gas trade. Despite traditional vertical chain bonds, increased flexibility has contributed in fact to an increasing LNG spot trade, representing 8% of global trade in 2002. The focus of this paper is on the development of global short-term LNG markets, and their role with respect to efficiency and security of supply in European gas markets. Arbitrage opportunities arising from price differences between regional markets (such as North America versus Europe) are important impetuses for flexible short-term trade. However, the short-term LNG trade may suffer from problems related to market access, e.g. limited access to terminals and regulatory issues, as well as rigidities connected to vertical binding within the LNG chain. Important issues related to the role of short-term LNG-trade in the European gas market are: Competition, flexibility in meeting peak demand, security of supply and consequences of differences in pricing policies (oil-linked prices in Europe and spot market prices in North America). (Author)

  6. Long term planning for wind energy development

    International Nuclear Information System (INIS)

    Trinick, M.

    1995-01-01

    In a planning system intended to be governed primarily by policies in statutory plans a reasonable horizon for long term planning is 10 years or longer. Because of statutory requirements, developers have no option but to pay due regard to, and take a full part in, long term planning. The paper examines the type of policies which have emerged in the last few years to cater for wind energy development. It canvasses the merits of different types of policies. Finally, it discusses the policy framework which may emerge to cater for development outside NFFO. (Author)

  7. The Legal Cause of Unfair Terms

    Directory of Open Access Journals (Sweden)

    Maximiliano Arango Grajales

    2016-01-01

    Full Text Available Unfair terms are outside the field of abuse. There’s not a potential risk of damage, there’s not an injury caused. Unfair terms belong to the field of the principle of equivalency of the contract. And through it, that the criterion of regulatory imbalance of the contract takes on meaning. The correction of such unfair clauses does not depend on weak parts or abuse but rather the existence of a breach of equivalence: an absence of consideration in the contract.

  8. Long-term characteristics of nuclear emulsion

    International Nuclear Information System (INIS)

    Naganawa, N; Kuwabara, K

    2010-01-01

    Long-term characteristics of the nuclear emulsion so called 'OPERA film' used in the neutrino oscillation experiment, OPERA, has been studied for 8 years since its production or refreshing after it. In the results, it turned out to be excellent in sensitivity, amount of random noise, and refreshing characteristics. The retention capacity of latent image of tracks was also studied. The result will open the way to the recycling of 7,000,000 emulsion films which will remain not developed after 5 years of OPERA's run, and other long-term experiments with emulsion.

  9. Long-term characteristics of nuclear emulsion

    Science.gov (United States)

    Naganawa, N.; Kuwabara, K.

    2010-02-01

    Long-term characteristics of the nuclear emulsion so called ``OPERA film'' used in the neutrino oscillation experiment, OPERA, has been studied for 8 years since its production or refreshing after it. In the results, it turned out to be excellent in sensitivity, amount of random noise, and refreshing characteristics. The retention capacity of latent image of tracks was also studied. The result will open the way to the recycling of 7,000,000 emulsion films which will remain not developed after 5 years of OPERA's run, and other long-term experiments with emulsion.

  10. Sportsman’s hernia? An ambiguous term

    Science.gov (United States)

    Dimitrakopoulou, Alexandra; Schilders, Ernest

    2016-01-01

    Groin pain is common in athletes. Yet, there is disagreement on aetiology, pathomechanics and terminology. A plethora of terms have been employed to explain inguinal-related groin pain in athletes. Recently, at the British Hernia Society in Manchester 2012, a consensus was reached to use the term inguinal disruption based on the pathophysiology while lately the Doha agreement in 2014 defined it as inguinal-related groin pain, a clinically based taxonomy. This review article emphasizes the anatomy, pathogenesis, standard clinical assessment and imaging, and highlights the treatment options for inguinal disruption. PMID:27026822

  11. Long-term home care scheduling

    DEFF Research Database (Denmark)

    Gamst, Mette; Jensen, Thomas Sejr

    In several countries, home care is provided for certain citizens living at home. The long-term home care scheduling problem is to generate work plans spanning several days such that a high quality of service is maintained and the overall cost is kept as low as possible. A solution to the problem...... provides detailed information on visits and visit times for each employee on each of the covered days. We propose a branch-and-price algorithm for the long-term home care scheduling problem. The pricing problem generates one-day plans for an employee, and the master problem merges the plans with respect...

  12. Second mid-term business plan results

    International Nuclear Information System (INIS)

    Kusakabe, Masashi; Matsushita, Satoru; Miyahara, Nobuyuki

    2011-01-01

    This feature presented the second mid-term business plan results of National Institute of Radiological Sciences (NIRS). NIRS started its second five-year-term project in 2006, focusing on radiation life science research, and radiation protection and emergency medicine. The radiation life science research had been conducted at research centers on heavy charged particle therapy for cancer treatment, assessment of radiation effects for radiotherapy, and molecular imaging for early diagnosis and treatment planning. NIRS also provided international open laboratory for experts of many fields to collaborate to enhance the levels of radiological sciences. Fundamental technology center had supported research centers through technology development. (T. Tanaka)

  13. Optimal Long-Term Financial Contracting

    OpenAIRE

    Peter M. DeMarzo; Michael J. Fishman

    2007-01-01

    We develop an agency model of financial contracting. We derive long-term debt, a line of credit, and equity as optimal securities, capturing the debt coupon and maturity; the interest rate and limits on the credit line; inside versus outside equity; dividend policy; and capital structure dynamics. The optimal debt-equity ratio is history dependent, but debt and credit line terms are independent of the amount financed and, in some cases, the severity of the agency problem. In our model, the ag...

  14. Long term storage techniques for 85Kr

    International Nuclear Information System (INIS)

    Foster, B.A.; Pence, D.T.; Staples, B.A.

    1975-01-01

    As new nuclear fuel reprocessing plants go on stream, the collection of fission product 85 Kr will be required to avoid potential local release problems and long-term atmospheric buildup. Storage of the collected 85 Kr for a period of at least 100 years will be necessary to allow approximately 99.9 percent decay before it is released. A program designed to develop and evaluate proposed methods for long-term storage of 85 Kr is discussed, and the results of a preliminary evaluation of three methods, high pressure steel cylinders, zeolite encapsulation, and clathrate inclusion are presented. (U.S.)

  15. Constraints on the affinity term for modeling long-term glass dissolution rates

    International Nuclear Information System (INIS)

    Bourcier, W.L.; Carroll, S.A.; Phillips, B.L.

    1993-11-01

    Predictions of long-term glass dissolution rates are highly dependent on the form of the affinity term in the rate expression. Analysis of the quantitative effect of saturation state on glass dissolution rate for CSG glass (a simple analog of SRL-165 glass), shows that a simple (1-Q/K) affinity term does not match experimental results. Our data at 100 degree C show that the data is better fit by an affinity term having the form (1 - (Q/K) 1 /σ) where σ = 10

  16. Near-Term Actions to Address Long-Term Climate Risk

    Science.gov (United States)

    Lempert, R. J.

    2014-12-01

    Addressing climate change requires effective long-term policy making, which occurs when reflecting on potential events decades or more in the future causes policy makers to choose near-term actions different than those they would otherwise pursue. Contrary to some expectations, policy makers do sometimes make such long-term decisions, but not as commonly and successfully as climate change may require. In recent years however, the new capabilities of analytic decision support tools, combined with improved understanding of cognitive and organizational behaviors, has significantly improved the methods available for organizations to manage longer-term climate risks. In particular, these tools allow decision makers to understand what near-term actions consistently contribute to achieving both short- and long-term societal goals, even in the face of deep uncertainty regarding the long-term future. This talk will describe applications of these approaches for infrastructure, water, and flood risk management planning, as well as studies of how near-term choices about policy architectures can affect long-term greenhouse gas emission reduction pathways.

  17. Short term and medium term power distribution load forecasting by neural networks

    International Nuclear Information System (INIS)

    Yalcinoz, T.; Eminoglu, U.

    2005-01-01

    Load forecasting is an important subject for power distribution systems and has been studied from different points of view. In general, load forecasts should be performed over a broad spectrum of time intervals, which could be classified into short term, medium term and long term forecasts. Several research groups have proposed various techniques for either short term load forecasting or medium term load forecasting or long term load forecasting. This paper presents a neural network (NN) model for short term peak load forecasting, short term total load forecasting and medium term monthly load forecasting in power distribution systems. The NN is used to learn the relationships among past, current and future temperatures and loads. The neural network was trained to recognize the peak load of the day, total load of the day and monthly electricity consumption. The suitability of the proposed approach is illustrated through an application to real load shapes from the Turkish Electricity Distribution Corporation (TEDAS) in Nigde. The data represents the daily and monthly electricity consumption in Nigde, Turkey

  18. 13 CFR 130.610 - General terms.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false General terms. 130.610 Section 130.610 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS DEVELOPMENT CENTERS... responsibilities of the recipient organization and SBA, the scope of the project to be funded, and the budget of...

  19. Experiences of long-term tranquillizer use

    DEFF Research Database (Denmark)

    Skinhoj, K T; Larsson, S; Helweg-Joergensen, S

    2001-01-01

    , the psychodynamic perspective is integrated within a multi-dimensional model that considers biological, cognitive, identity, gender and social learning factors. The analysis reveals the possibility of achieving a detailed understanding of the dynamic processes involved in the development of long-term tranquillizer...

  20. Unfair terms in contracts between businesses

    NARCIS (Netherlands)

    Hesselink, M.W.; Schulze, R.; Stuyck, J.

    2011-01-01

    This paper examines the main possible rationales for judicial control of unfair contract terms (unequal bargaining, distributive justice, market failure, paternalism, the ethos of the market, comparative law, and the nature of an optional instrument) and concludes that none of them requires a

  1. Visual Short-Term Memory Complexity

    DEFF Research Database (Denmark)

    Sørensen, Thomas Alrik

    Several recent studies have explored the nature and limits of visual short-term memory (VSTM) (e.g. Luck & Vogel, 1997). A general VSTM capacity limit of about 3 to 4 letters has been found, thus confirming results from earlier studies (e.g. Cattell, 1885; Sperling, 1960). However, Alvarez...

  2. When “small” terms matter

    DEFF Research Database (Denmark)

    Solomon, Gemma C.; Bergfield, Justin Philip; Stafford, Charles A.

    2011-01-01

    -body theory to calculate the transport through several single-molecule junctions, finding that terms that are generally thought to only slightly perturb the transport instead produce significant qualitative changes in the transport properties. In particular, we show that coupling of multiple interference...

  3. Ecological Environment in Terms of Human Behavior

    OpenAIRE

    Chen, Xiaogang; Zhou, Dehu; Lin, Hui

    2013-01-01

    In terms of human behavior, company and government policy, it is proposed that the ecological behavior of human being is the basis of influence on the ecological environment construction in Poyang Lake and measures to ensure the sustainable development of ecological environment in Poyang Lake.

  4. Discrete choice models with multiplicative error terms

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Bierlaire, Michel

    2009-01-01

    The conditional indirect utility of many random utility maximization (RUM) discrete choice models is specified as a sum of an index V depending on observables and an independent random term ε. In general, the universe of RUM consistent models is much larger, even fixing some specification of V due...

  5. Robustness of behavioral equivalence on open terms

    NARCIS (Netherlands)

    Mosses, P.D.; Mousavi, M.R.; Reniers, M.A.

    2010-01-01

    Sound behavioral equations on open terms may become unsound after conservative extensions of the underlying operational semantics. Providing criteria under which such equations are preserved is extremely useful; in particular, it can avoid the need to repeat proofs when extending the specified

  6. Neutrino proton scattering and the isosinglet term

    International Nuclear Information System (INIS)

    White, D.H.

    1990-01-01

    Elastic neutrino proton scattering is sensitive to the SU(3) axial isosinglet term which is in turn dependent on the strangeness content of the proton. The uncertainties in the analysis of a neutrino proton elastic scattering experiment are discussed, and an experiment which is insensitive to many of the difficulties of the previous experiment is described

  7. 16 CFR 502.2 - Terms defined.

    Science.gov (United States)

    2010-01-01

    ... Commercial Practices FEDERAL TRADE COMMISSION RULES, REGULATIONS, STATEMENT OF GENERAL POLICY OR... and customary and regular when used with the term price means the price at which a consumer commodity... commodities which fluctuate in price, the ordinary and customary price shall be the lowest price at which any...

  8. Term Structure Analysis with Big Data

    DEFF Research Database (Denmark)

    Andreasen, Martin Møller; Christensen, Jens H.E.; Rudebusch, Glenn D.

    Analysis of the term structure of interest rates almost always takes a two-step approach. First, actual bond prices are summarized by interpolated synthetic zero-coupon yields, and second, a small set of these yields are used as the source data for further empirical examination. In contrast, we...

  9. 7 CFR 51.892 - Color terms.

    Science.gov (United States)

    2010-01-01

    ... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States.... Table IV Color terms Black varieties Red varieties White varieties Well colored (U.S. Extra Fancy) Each... varieties shall have not less than 75 percent, by count, of berries showing characteristic color. 2 No...

  10. Safety of long-term PPI therapy

    DEFF Research Database (Denmark)

    Reimer, Christina

    2013-01-01

    Proton pump inhibitors have become the mainstay of medical treatment of acid-related disorders. Long-term use is becoming increasingly common, in some cases without a proper indication. A large number of mainly observational studies on a very wide range of possible associations have been publishe...... to a careful evaluation of the indication for PPI treatment....

  11. Long term consequences of early childhood malnutrition

    NARCIS (Netherlands)

    Kinsey, B.H.; Hoddinott, J; Alderman, H.

    2006-01-01

    This paper examines the impact of pre-school malnutrition on subsequent human capital formation in rural Zimbabwe using a maternal fixed effects - instrumental variables (MFE-IV) estimator with a long term panel data set. Representations of civil war and drought shocks are used to identify

  12. 7 CFR 28.950 - Terms defined.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing..., TESTING, AND STANDARDS Cotton Fiber and Processing Tests Definitions § 28.950 Terms defined. As used... Agricultural Marketing Service of the U.S. Department of Agriculture. (c) Administrator. The Administrator of...

  13. 7 CFR 28.2 - Terms defined.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing..., TESTING, AND STANDARDS Regulations Under the United States Cotton Standards Act Definitions § 28.2 Terms... to act for the Secretary. (e) Service. The Agricultural Marketing Service of the U.S. Department of...

  14. QUIESST: mid-term progress report

    NARCIS (Netherlands)

    Clairbois, J.-P.; Roo, F. de; Garai, M.; Conter, M.; Defrance, J.; Oltean-Dumbrava, C.; Fusco, I.

    2011-01-01

    The research QUIESST (QUIetening the Environment of Sustainable Surface Transport) successfully started in November 2009 for 36 months, its objectives and work schedule have already been presented at the INTERNOISE 2010 Congress. This paper will present the progress report at mid-term (18 months):

  15. Immunohistochemical evaluation of iron accumulation in term ...

    African Journals Online (AJOL)

    Classical immunohistochemical studies on placenta have shown that there is a linear increase in iron storage in the placenta in the first half of a normal pregnancy, however, these stocks are decreased in normal 3rd trimester placenta. Iron accumulation in term placentas of preeclamptic and normal pregnancies were ...

  16. 42 CFR 442.2 - Terms.

    Science.gov (United States)

    2010-10-01

    ... ASSISTANCE PROGRAMS STANDARDS FOR PAYMENT TO NURSING FACILITIES AND INTERMEDIATE CARE FACILITIES FOR THE MENTALLY RETARDED General Provisions § 442.2 Terms. In this part— Facility refers to a nursing facility..., harm, impairment, or death to an individual receiving care in a facility. New admission means the...

  17. Financial Incentives in Long-Term Care

    NARCIS (Netherlands)

    P.L.H. Bakx (Pieter)

    2015-01-01

    markdownabstract__Abstract__ Long-term care (ltc) aims to help individuals to cope with their impairments. In my thesis, I describe ltc financing alternatives and their consequences for the allocation of ltc. This thesis consists of two parts. In the first part, I investigate how alternative ways

  18. Award-term contracts: Good for business?

    OpenAIRE

    Stevens, Brett; Yoder, E. Cory

    2005-01-01

    The use of award-term contracts doesn’t seem to represent the best interests of the U.S. taxpayer—rather, it smacks terribly of the government acquisition environment of two decades ago that pre- ceded the passage of the Competition in Contracting Act.

  19. Long-term outcomes of patellofemoral arthroplasty.

    NARCIS (Netherlands)

    Jonbergen, J.P.W. van; Werkman, D.M.; Barnaart, L.F.; Kampen, A. van

    2010-01-01

    The purpose of this study was to correlate the long-term survival of patellofemoral arthroplasty with primary diagnosis, age, sex, and body mass index. One hundred eighty-five consecutive Richards type II patellofemoral arthroplasties were performed in 161 patients with isolated patellofemoral

  20. 16 CFR 500.2 - Terms defined.

    Science.gov (United States)

    2010-01-01

    ... individuals, or use by individuals for purposes of personal care or in the performance of services ordinarily... or outer wrappings used by retailers to ship or deliver any commodity to retail customers if such... practical importance. (k) The term customary inch/pound refers to units belonging to the system of units...

  1. Analyzing rare diseases terms in biomedical terminologies

    Directory of Open Access Journals (Sweden)

    Erika Pasceri

    2012-03-01

    Full Text Available Rare disease patients too often face common problems, including the lack of access to correct diagnosis, lack of quality information on the disease, lack of scientific knowledge of the disease, inequities and difficulties in access to treatment and care. These things could be changed by implementing a comprehensive approach to rare diseases, increasing international cooperation in scientific research, by gaining and sharing scientific knowledge about and by developing tools for extracting and sharing knowledge. A significant aspect to analyze is the organization of knowledge in the biomedical field for the proper management and recovery of health information. For these purposes, the sources needed have been acquired from the Office of Rare Diseases Research, the National Organization of Rare Disorders and Orphanet, organizations that provide information to patients and physicians and facilitate the exchange of information among different actors involved in this field. The present paper shows the representation of rare diseases terms in biomedical terminologies such as MeSH, ICD-10, SNOMED CT and OMIM, leveraging the fact that these terminologies are integrated in the UMLS. At the first level, it was analyzed the overlap among sources and at a second level, the presence of rare diseases terms in target sources included in UMLS, working at the term and concept level. We found that MeSH has the best representation of rare diseases terms.

  2. The Term Innovation and its Front End

    DEFF Research Database (Denmark)

    Brem, Alexander

    2009-01-01

    , before the background of globalized economies, a common understanding is needed for successful future intercultural projects and appropriate management. Especially in scientific research, a first step should be made in this direction. Therefore, a comprehensive view of the term innovation and its...

  3. The 2013 Long-Term Budget Outlook

    Science.gov (United States)

    2013-09-01

    number of years, leading to substantial additional federal spending. For example, the nation could experience a massive earthquake, a nuclear meltdown...budget surpluses remaining after paying down publicly held debt available for redemption . a. For comparison with the current long-term projections, CBO

  4. Long-term effects of ionizing radiation

    International Nuclear Information System (INIS)

    Kaul, Alexander; Burkart, Werner; Grosche, Bernd; Jung, Thomas; Martignoni, Klaus; Stephan, Guenther

    1997-01-01

    This paper approaches the long-term effects of ionizing radiation considering the common thought that killing of cells is the basis for deterministic effects and that the subtle changes in genetic information are important in the development of radiation-induced cancer, or genetic effects if these changes are induced in germ cells

  5. Medium-Term Oil Market Report 2006

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    How much oil will the world consume in 2011? What role will OPEC play in global oil production? Will biofuels become an important part of the oil market? The International Energy Agencys (IEA) Medium-Term Oil Market Report tackles these questions, adopting a perspective that goes beyond the traditional short-term market analysis provided in the IEAs monthly Oil Market Report. Drawing on current futures curves and the investment threshold for upstream projects, the Medium-Term Oil Market Report analyses how global demand and supply balances may develop in the next five years. The forecasts look in detail at product demand and the supply potential from all the firmly planned individual upstream and downstream projects around the world. The results provide invaluable insights on vital issues such as surplus production capacity and product supply. The rapid pace of change in the oil market means that forecasts can become outdated very quickly. This interim update provides the opportunity to rebase the data and forecasts in the annual Medium-Term Oil Market Report and to discuss and analyse new issues affecting the oil industry. Policymakers, market analysts, energy experts and anyone interested in understanding and following trends in the oil market should find this report extremely useful.

  6. 78 FR 31885 - Patent Term Extension

    Science.gov (United States)

    2013-05-28

    ... DEPARTMENT OF COMMERCE Patent and Trademark Office Patent Term Extension ACTION: Proposed collection; comment request. SUMMARY: The United States Patent and Trademark Office (USPTO), as part of its... States Patent and Trademark Office, P.O. Box 1450, Alexandria, VA 22313-1450. Federal Rulemaking Portal...

  7. 75 FR 20561 - Patent Term Extension

    Science.gov (United States)

    2010-04-20

    ... DEPARTMENT OF COMMERCE Patent and Trademark Office Patent Term Extension ACTION: Proposed collection; comment request. SUMMARY: The United States Patent and Trademark Office (USPTO), as part of its... Officer, Office of the Chief Information Officer, United States Patent and Trademark Office, P.O. Box 1450...

  8. Subsurface Shielding Source Term Specification Calculation

    International Nuclear Information System (INIS)

    S.Su

    2001-01-01

    The purpose of this calculation is to establish appropriate and defensible waste-package radiation source terms for use in repository subsurface shielding design. This calculation supports the shielding design for the waste emplacement and retrieval system, and subsurface facility system. The objective is to identify the limiting waste package and specify its associated source terms including source strengths and energy spectra. Consistent with the Technical Work Plan for Subsurface Design Section FY 01 Work Activities (CRWMS M and O 2001, p. 15), the scope of work includes the following: (1) Review source terms generated by the Waste Package Department (WPD) for various waste forms and waste package types, and compile them for shielding-specific applications. (2) Determine acceptable waste package specific source terms for use in subsurface shielding design, using a reasonable and defensible methodology that is not unduly conservative. This calculation is associated with the engineering and design activity for the waste emplacement and retrieval system, and subsurface facility system. The technical work plan for this calculation is provided in CRWMS M and O 2001. Development and performance of this calculation conforms to the procedure, AP-3.12Q, Calculations

  9. The term 'risk' and its evaluation bases

    International Nuclear Information System (INIS)

    Brueckner, R.

    1976-01-01

    The term risk, the risk itself and its application for radiation exposure in practised medicine is presented from the following points of view: Life expectation, susceptibility to sickness and permanent inability to work, impaired professional and earning capacity, work accident and sickness. (HP) [de

  10. Pituitary diseases : long-term psychological consequences

    NARCIS (Netherlands)

    Tiemensma, Jitske

    2012-01-01

    Nowadays, pituitary adenomas can be appropriately treated, but patients continue to report impaired quality of life (QoL) despite long-term remission or cure. In patients with Cushing’s disease, Cushing’s syndrome or acromegaly, doctors should be aware of subtle cognitive impairments and the

  11. Medium-Term Oil Market Report 2007

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    How much oil will the world consume in 2012? What role will OPEC play in global oil production? Will biofuels become an important part of the oil market? How will the refinery sector cope? The International Energy Agency (IEA) Medium-Term Oil Market Report tackles these questions, adopting a perspective that goes beyond the traditional short-term market analysis provided in the IEA Oil Market Report. Drawing on current futures curves and the investment threshold for upstream projects, the Medium-Term Oil Market Report analyses how global demand and supply balances may develop. By assessing all firmly planned upstream and downstream projects worldwide, this report forecasts supply and demand potential for crude and petroleum products over the next five years. The results provide an invaluable insight into vital issues such as surplus production capacity and product supply. An essential report for all policymakers, market analysts, energy experts and anyone interested in understanding and following oil market trends, the Medium-Term Oil Market Report is a further element of the strong commitment of the IEA to improving and expanding the quality, timeliness and accuracy of energy data and analysis.

  12. Breech at term--mode of delivery?

    DEFF Research Database (Denmark)

    Krebs, L; Langhoff-Roos, J; Weber, T

    1995-01-01

    BACKGROUND: The present study was designed to determine neonatal mortality and morbidity in non-malformed singleton term infants delivered in breech presentation and identify a possible correlation between outcome on the one hand and mode of delivery, parity and birth weight on the other. METHODS...

  13. Many general language dictionaries contain specialized terms

    African Journals Online (AJOL)

    user

    used in England and Wales in the light of the change of structure of and terminology ... Legal Terms in General Dictionaries of English: The Civil Procedure Mystery ... (2015: 8), between 1.4 million and 2.1 million cases annually were brought.

  14. The long term stability of lidar calibrations

    DEFF Research Database (Denmark)

    Courtney, Michael; Gayle Nygaard, Nicolai

    Wind lidars are now used extensively for wind resource measurements. One of the requirements for the data to be accepted in support of project financing (so-called ‘banka-bility’) is to demonstrate the long-term stability of lidar cali-brations. Calibration results for six Leosphere WindCube li...

  15. 42 CFR 93.50 - Special terms.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Special terms. 93.50 Section 93.50 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES HEALTH ASSESSMENTS AND HEALTH EFFECTS STUDIES OF HAZARDOUS SUBSTANCES RELEASES AND FACILITIES PUBLIC HEALTH SERVICE POLICIES ON RESEARCH...

  16. Rebalancing for Long-Term Investors

    NARCIS (Netherlands)

    Driessen, Joost; Kuiper, Ivo

    2017-01-01

    In this study we show that the rebalance frequency of a multi-asset portfolio has only limited impact on the utility of a long-term passive investor. Although continuous rebalancing is optimal, the loss of a suboptimal strategy corresponds to up to only 30 basis points of the initial wealth of the

  17. English Law Terms: Optimizing Education Process

    Directory of Open Access Journals (Sweden)

    Alexandra G. Anisimova

    2014-01-01

    Full Text Available The article focuses on the terminology of English law as a system. It deals with the main specific characteristics of the English legal terminology and studies the systemic nature of the terminology of Criminal Law. Nowadays, an increasing role of the study of professional language (Language for Specific Purposes is obvious since it is a means of dissemination and exchange of professional information and a means of communication in the professional discourse. It is a system of terms that constitutes the core of the Language for Specific Purposes. The study of terminology is of paramount importance for the legal sphere of human activity where the accuracy of interpretation plays a very substantial part. Legal terms have a number of specific characteristics, such as: abstract nature of legal notions; introduction of new terms by regulatory organizations; an important role of judicial interpretation in constituting shades of meaning of a legal terminological unit; and the fact that a legal term may belong to a particular area of Law, which makes it possible to refer it to the category of general legal, branch-wise, or inter-branch vocabulary. Every term has its particular place among other elements of a system and is related to them in a particular way. A terminological system should be considered as a whole, and there are particular hierarchical relations between its elements. Within a terminological system, it is possible to seta hierarchy of generic and specific terms that can form the so-called semantic field. One of the features demonstrating the systemic links within a terminology is the existence of some typical structural models, according to which terms are coined. An important criterion is the predominance ofterminological word-combinations of a certain type. For example, in the terminology of Criminal Law the models Noun + Preposition + Noun and Adjective + Noun are the most common structural models. Another important criterion of a

  18. Long-term course of opioid addiction.

    Science.gov (United States)

    Hser, Yih-Ing; Evans, Elizabeth; Grella, Christine; Ling, Walter; Anglin, Douglas

    2015-01-01

    Opioid addiction is associated with excess mortality, morbidities, and other adverse conditions. Guided by a life-course framework, we review the literature on the long-term course of opioid addiction in terms of use trajectories, transitions, and turning points, as well as other factors that facilitate recovery from addiction. Most long-term follow-up studies are based on heroin addicts recruited from treatment settings (mostly methadone maintenance treatment), many of whom are referred by the criminal justice system. Cumulative evidence indicates that opioid addiction is a chronic disorder with frequent relapses. Longer treatment retention is associated with a greater likelihood of abstinence, whereas incarceration is negatively related to subsequent abstinence. Over the long term, the mortality rate of opioid addicts (overdose being the most common cause) is about 6 to 20 times greater than that of the general population; among those who remain alive, the prevalence of stable abstinence from opioid use is low (less than 30% after 10-30 years of observation), and many continue to use alcohol and other drugs after ceasing to use opioids. Histories of sexual or physical abuse and comorbid mental disorders are associated with the persistence of opioid use, whereas family and social support, as well as employment, facilitates recovery. Maintaining opioid abstinence for at least five years substantially increases the likelihood of future stable abstinence. Recent advances in pharmacological treatment options (buprenorphine and naltrexone) include depot formulations offering longer duration of medication; their impact on the long-term course of opioid addiction remains to be assessed.

  19. Augmented Reality in Informal Learning Environments: Investigating Short-term and Long-term Effects

    DEFF Research Database (Denmark)

    Sommerauer, Peter; Müller, Oliver

    2018-01-01

    field experiment with 24 participants at a mathematics exhibition to measure the effect of AR on acquiring and retaining mathematical knowledge in an informal learning environment, both short-term (i.e., directly after visiting the exhibition) and long-term (i.e., two months after the museum visit). Our...

  20. The uranium industry: long-term planning for short-term competition

    International Nuclear Information System (INIS)

    Vottero, X.; Georges Capus, G.

    2001-01-01

    Long term planning for short term competition Today, uranium producers face new challenges in terms of both production (new regulatory, environmental and social constraints) and market conditions (new sources of uranium supply, very low prices and tough competition). In such a context, long-term planning is not just a prerequisite to survive in the nuclear fuel cycle industry. In fact, it also contributes to sustaining nuclear electricity generation facing fierce competition from other energy sources in increasingly deregulated markets. Firstly, the risk of investing in new mining projects in western countries is growing because, on the one hand, of very erratic market conditions and, on the other hand, of increasingly lengthy, complex and unpredictable regulatory conditions. Secondly, the supply of other sources of uranium (uranium derived from nuclear weapons, uranium produced in CIS countries, ...) involve other risks, mainly related to politics and commercial restrictions. Consequently, competitive uranium supply requires not only technical competence but also financial strength and good marketing capabilities in order to anticipate long-term market trends, in terms of both demand and supply. It also requires taking into account new parameters such as politics, environment, regulations, etc. Today, a supplier dedicated to the sustainable production of nuclear electricity must manage a broad range of long-term risks inherent to the procurement of uranium. Taking into account all these parameters in a context of short-term, fast-changing market is a great challenge for the future generation. World Uranium Civilian Supply and Demand. (authors)

  1. Semantic and phonological contributions to short-term repetition and long-term cued sentence recall.

    Science.gov (United States)

    Meltzer, Jed A; Rose, Nathan S; Deschamps, Tiffany; Leigh, Rosie C; Panamsky, Lilia; Silberberg, Alexandra; Madani, Noushin; Links, Kira A

    2016-02-01

    The function of verbal short-term memory is supported not only by the phonological loop, but also by semantic resources that may operate on both short and long time scales. Elucidation of the neural underpinnings of these mechanisms requires effective behavioral manipulations that can selectively engage them. We developed a novel cued sentence recall paradigm to assess the effects of two factors on sentence recall accuracy at short-term and long-term stages. Participants initially repeated auditory sentences immediately following a 14-s retention period. After this task was complete, long-term memory for each sentence was probed by a two-word recall cue. The sentences were either concrete (high imageability) or abstract (low imageability), and the initial 14-s retention period was filled with either an undemanding finger-tapping task or a more engaging articulatory suppression task (Exp. 1, counting backward by threes; Exp. 2, repeating a four-syllable nonword). Recall was always better for the concrete sentences. Articulatory suppression reduced accuracy in short-term recall, especially for abstract sentences, but the sentences initially recalled following articulatory suppression were retained better at the subsequent cued-recall test, suggesting that the engagement of semantic mechanisms for short-term retention promoted encoding of the sentence meaning into long-term memory. These results provide a basis for using sentence imageability and subsequent memory performance as probes of semantic engagement in short-term memory for sentences.

  2. Short-term and long-term deflection of reinforced hollow core ...

    African Journals Online (AJOL)

    This paper presents a study on different methods of analysis that are currently used by design codes to predict the short-term and long-term deflection of reinforced concrete slab systems and compares the predicted deflections with measured deflections. The experimental work to measure deflections involved the testing of ...

  3. Very-long-term and short-term chromatic adaptation: are their influences cumulative?

    Science.gov (United States)

    Belmore, Suzanne C; Shevell, Steven K

    2011-02-09

    Very-long-term (VLT) chromatic adaptation results from exposure to an altered chromatic environment for days or weeks. Color shifts from VLT adaptation are observed hours or days after leaving the altered environment. Short-term chromatic adaptation, on the other hand, results from exposure for a few minutes or less, with color shifts measured within seconds or a few minutes after the adapting light is extinguished; recovery to the pre-adapted state is complete in less than an hour. Here, both types of adaptation were combined. All adaptation was to reddish-appearing long-wavelength light. Shifts in unique yellow were measured following adaptation. Previous studies demonstrate shifts in unique yellow due to VLT chromatic adaptation, but shifts from short-term chromatic adaptation to comparable adapting light can be far greater than from VLT adaptation. The question considered here is whether the color shifts from VLT adaptation are cumulative with large shifts from short-term adaptation or, alternatively, does simultaneous short-term adaptation eliminate color shifts caused by VLT adaptation. The results show the color shifts from VLT and short-term adaptation together are cumulative, which indicates that both short-term and very-long-term chromatic adaptation affect color perception during natural viewing. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. The interaction of short-term and long-term memory in phonetic category formation

    Science.gov (United States)

    Harnsberger, James D.

    2002-05-01

    This study examined the role that short-term memory capacity plays in the relationship between novel stimuli (e.g., non-native speech sounds, native nonsense words) and phonetic categories in long-term memory. Thirty native speakers of American English were administered five tests: categorial AXB discrimination using nasal consonants from Malayalam; categorial identification, also using Malayalam nasals, which measured the influence of phonetic categories in long-term memory; digit span; nonword span, a short-term memory measure mediated by phonetic categories in long-term memory; and paired-associate word learning (word-word and word-nonword pairs). The results showed that almost all measures were significantly correlated with one another. The strongest predictor for the discrimination and word-nonword learning results was nonword (r=+0.62) and digit span (r=+0.51), respectively. When the identification test results were partialed out, only nonword span significantly correlated with discrimination. The results show a strong influence of short-term memory capacity on the encoding of phonetic detail within phonetic categories and suggest that long-term memory representations regulate the capacity of short-term memory to preserve information for subsequent encoding. The results of this study will also be discussed with regards to resolving the tension between episodic and abstract models of phonetic category structure.

  5. Short-term and long-term sick-leave in Sweden

    DEFF Research Database (Denmark)

    Blank, N; Diderichsen, Finn

    1995-01-01

    The primary aim of the study was to analyse similarities and differences between repeated spells of short-term sick-leave (more than 3 spells of less than 7 days' duration in a 12-month period) and long-term absence through sickness (at least 1 spell of more than 59 days' duration in a 12-month p...

  6. Potentials of short term and long term cryopreserved sperm of the ...

    African Journals Online (AJOL)

    To service the growing demand for male African giant catfish (Clarias gariepinus) broodstock for aquaculture in Nigeria, and to conserve valuable genetic resources, we improved both short-term (in deep freezer at -35°C) and long-term cryopreservation (in liquid nitrogen at -296°C) of catfish sperm. Catfish sperm ...

  7. Opening remarks for a panel discussion on short-term vs long-term procurement

    International Nuclear Information System (INIS)

    Courtenay, R.H.

    1990-01-01

    Long-term contracting in the late 1970's and early 1980's is blamed for some of the inequities that plague the uranium industry today. Utilities are obliged to pay prices far above prevailing levels and relatively low cost producers are forced to shut down while watching less efficient suppliers stay in business thanks to their long term supply agreements. Furthermore, it is argued that long-term contracts have contributed to supply instability by forcing the buildup of surplus inventories and by supporting excess incremental production by suppliers who have a baseload of long-term contracts. The depressed prices resulting from this oversupply are in turn jeopardizing future resource development and damaging supply reliability. In summary, the author's argument is that supply reliability will be greatly enhanced by the assurance of adequate primary supply from traditional sources such as Canada. This will not happen without long-term contracts. This conclusion may not be expected coming from a representative of Canada's largest uranium producer. But the final comment is less self serving. Many of the critics of long term contracts apparently expect a continuing and plentiful supply of East Bloc uranium to the spot market. A further question is to what extent East Bloc suppliers will eventually require long-term contracts in order to maintain production facilitates in economies that are no longer centrally planned, and where there is open competition for capital. Ultimately, reliability of supply from the non-traditional suppliers may also depend on long-term contracts

  8. The Dynamics of Terms in Accounting

    DEFF Research Database (Denmark)

    Fuertes-Olivera, Pedro A.; Nielsen, Sandro

    2011-01-01

    . However, an analysis of online dictionaries shows that these cannot cope with the dynamic nature of accounting terminology. We discuss a network of internet dictionaries in English, Danish, and Spanish that was compiled using the functional approach to specialised lexicography. We show how terminologists...... can work in subject fields where culture and context play a key role in the development of nationally accepted and internationally recommended terms, and propose ways to remedy deficiencies identified in the dictionaries examined. Finally, we discuss strategies for translating English metaphorical......European accounting terminology is dynamic as term creation and formation occurs on national, European Union and international levels. Although English is the lingua franca of accounting, international accounting standards in English exist on a par with their translations into other languages...

  9. Greenland unveils terms for offshore licenses

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that Greenland has spelled out terms for its first round of offshore licensing. The action off western Greenland could lead to the first oil and gas exploration there since an unsuccessful campaign in the 1970s. The Mineral Resources Administration (MRA) for Greenland pegged exploration license terms on 133 blocks, all south of the 66th parallel, at 10 years with options for 2 year extensions to a maximum of 6 more years. The license can cover as many as six blocks. In the first 3 year period companies will have only a seismic obligation of 1,588 km per six blocks. For the second 3 year period there will be a one well obligation and one well in each subsequent 2 year periods

  10. Delivery at Term: When, How, and Why.

    Science.gov (United States)

    Walker, Kate F; Thornton, Jim G

    2018-06-01

    There is growing evidence from randomized trials that induction of labor at or near term does not increase cesarean delivery; observational data show that the optimal gestation for spontaneous delivery for the baby is 39 weeks. Elective cesarean at these gestations is also sometimes considered, but evaluating the associated risks is complex. For the baby, although cesarean obviates the risks of labor, it carries a risk of respiratory problems, which may be severe. For the mother, cesarean is more dangerous than vaginal and emergency cesarean is more dangerous than elective. The authors consider the evidence base for near-term induction of labor and cesarean for a range of scenarios. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Source term estimation for small sized HTRs

    International Nuclear Information System (INIS)

    Moormann, R.

    1992-08-01

    Accidents which have to be considered are core heat-up, reactivity transients, water of air ingress and primary circuit depressurization. The main effort of this paper belongs to water/air ingress and depressurization, which requires consideration of fission product plateout under normal operation conditions; for the latter it is clearly shown, that absorption (penetration) mechanisms are much less important than assumed sometimes in the past. Source term estimation procedures for core heat-up events are shortly reviewed; reactivity transients are apparently covered by them. Besides a general literature survey including identification of areas with insufficient knowledge this paper contains some estimations on the thermomechanical behaviour of fission products in water in air ingress accidents. Typical source term examples are also presented. In an appendix, evaluations of the AVR experiments VAMPYR-I and -II with respect to plateout and fission product filter efficiency are outlined and used for a validation step of the new plateout code SPATRA. (orig.)

  12. Long-term selenium status in humans

    International Nuclear Information System (INIS)

    Baskett, C.K.; Spate, V.L.; Mason, M.M.; Nichols, T.A.; Williams, A.; Dubman, I.M.; Gudino, A.; Denison, J.; Morris, J.S.

    2001-01-01

    The association of sub-optimal selenium status with increased risk factors for some cancers has been reported in two recent epidemiological studies. In both studies the same threshold in selenium status was observed, below which, cancer incidence increased. To assess the use of nails as a biologic monitor to measure the long-term selenium status, an eight-year longitudinal study was undertaken with a group of 11 adult subjects, 5 women and 6 men. Selenium has been measured by instrumental neutron activation analysis. Differences between fingernails and toenails with be discussed. In addition, the results will be discussed in the context of the long-term stability of the nail monitor to measure selenium status during those periods when selenium determinants are static; and the changes that occur as a result of selenium supplementation. (author)

  13. Industrial Foundations as Long‐term Owners

    DEFF Research Database (Denmark)

    Thomsen, Steen; Poulsen, Thomas; Børsting, Christa Winther

    2018-01-01

    Research Question/Issue: Does foundation ownership lead to long‐term corporate governance and business behavior in foundation‐owned companies? Research Findings/Insights: Short‐termism has become a serious concern for corporate governance, and this has inspired a search for institutional...... that practice long‐term governance.We show that foundation ownership is highly stable compared to other ownership structures. Foundation‐owned companies replace managers less frequently. They have conservative capital structures with low financial leverage. They score higheron an index of long......‐termism in finance, investment, and employment. They survivelonger. Overall, our paper supports the hypothesis that corporate time horizons are influenced by ownership structures, and particularly that industrial foundations possess characteristics that promote long‐termism. Policymakers, business owners...

  14. Influenza in long-term care facilities.

    Science.gov (United States)

    Lansbury, Louise E; Brown, Caroline S; Nguyen-Van-Tam, Jonathan S

    2017-09-01

    Long-term care facility environments and the vulnerability of their residents provide a setting conducive to the rapid spread of influenza virus and other respiratory pathogens. Infections may be introduced by staff, visitors or new or transferred residents, and outbreaks of influenza in such settings can have devastating consequences for individuals, as well as placing extra strain on health services. As the population ages over the coming decades, increased provision of such facilities seems likely. The need for robust infection prevention and control practices will therefore remain of paramount importance if the impact of outbreaks is to be minimised. In this review, we discuss the nature of the problem of influenza in long-term care facilities, and approaches to preventive and control measures, including vaccination of residents and staff, and the use of antiviral drugs for treatment and prophylaxis, based on currently available evidence. © 2017 The Authors. Influenza and Other Respiratory Viruses Published by John Wiley & Sons Ltd.

  15. Long-Term Ownership by Industrial Foundations

    DEFF Research Database (Denmark)

    Børsting, Christa Winther; Kuhn, Johan Moritz; Poulsen, Thomas

    2016-01-01

    in Denmark. Industrial foundations are independent legal entities without owners or members typically with the dual objective of preserving the company and using excess profits for charity. We use a unique Danish data set to examine the governance of foundation-owned companies. We show that they are long......-term in several respects. Foundations hold on to their shares for longer. Foundation-owned companies replace managers less frequently. They have more conservative capital structures with less leverage. Their companies survive longer. Their business decisions appear to be more long term. This paper supports...... the hypothesis that time horizons are influenced by ownership structures and particularly that industrial foundations promote longtermism. Policymakers which are interested in promoting longtermism should allow and perhaps even encourage the creation of industrial foundations. More generally they should consider...

  16. Analysis of long-term energy scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Lemming, J.; Morthorst, P.E.

    1998-09-01

    When addressing the role of fusion energy in the 21. century, the evaluation of possible future structures in the electricity market and the energy sector as a whole, can be a useful tool. Because fusion energy still needs demonstration, commercialized fusion energy is not likely to be a reality within the next few decades. Therefore long-term scenarios are needed describing the energy markets, which fusion energy eventually will be part of. This report performs an analysis of two of the most detailed existing long-term scenarios describing possible futures of the energy system. The aim is to clarify the frames in which the future development of the global energy demand, as well as the structure of the energy system can be expected to develop towards the year 2100. (au) 19 refs.

  17. Retracing the etymology of terms in neuroanatomy.

    Science.gov (United States)

    Paluzzi, Alessandro; Fernandez-Miranda, Juan; Torrenti, Matthew; Gardner, Paul

    2012-11-01

    Researching the origin of the terms that we use to identify neuroanatomical structures is a helpful and fascinating exercise. It can provide neuroscientists with a better insight and understanding of the macroscopic anatomy of the cranium and its contents. It can also help the novice to this discipline to become acquainted with structures whose three dimensional anatomy is often difficult to appreciate. The purpose of this article was to investigate the etymology of some of the terms referring to the macroscopic anatomical structures of the skull and the intracranial cavity. We observed how each name unravels an interesting story, sometimes linked to mythological creatures, other times to the shape of animals or objects and tools of everyday life. We conclude that even without a deep knowledge of the Greek, Latin, or Arabic language, learning who described a particular structure and how they decided to name it, makes the study of neuroanatomy more complete and fulfilling. Copyright © 2012 Wiley Periodicals, Inc.

  18. Jaundice in the full-term newborn.

    Science.gov (United States)

    Cohen, Shannon Munro

    2006-01-01

    Jaundice is a common problem affecting over half of all full-term and most preterm infants. Jaundice describes the yellow orange hue of the skin caused by excessive circulating levels of bilirubin that accumulate in the skin. In most healthy full-term newborns, jaundice is noticed during the first week of life. Shortened hospital stays and inconsistent follow up, especially for first-time breastfeeding mothers, prompted the American Academy of Pediatrics (AAP) to update management guidelines. Health care providers need to be familiar with the diagnosis and management of jaundice to prevent brain, vision, and hearing damage. Treatment of choice for jaundice remains close observation and frequent feeding followed by phototherapy, and finally exchange transfusion for severe or refractory cases.

  19. Long-term effects of radiation

    International Nuclear Information System (INIS)

    Smith, J.; Smith, T.

    1981-01-01

    It is pointed out that sources of long-term damage from radiation are two-fold. People who have been exposed to doses of radiation from initial early fallout but have recovered from the acute effects may still suffer long-term damage from their exposure. Those who have not been exposed to early fallout may be exposed to delayed fallout, the hazards from which are almost exclusively from ingesting strontium, caesium and carbon isotopes present in food; the damage caused is relatively unimportant compared with that caused by the brief doses from initial radiation and early fallout. A brief discussion is presented of the distribution of delayed long-lived isotope fallout, and an outline is sketched of late biological effects, such as malignant disease, cataracts, retarded development, infertility and genetic effects. (U.K.)

  20. Hamiltonian boundary term and quasilocal energy flux

    International Nuclear Information System (INIS)

    Chen, C.-M.; Nester, James M.; Tung, R.-S.

    2005-01-01

    The Hamiltonian for a gravitating region includes a boundary term which determines not only the quasilocal values but also, via the boundary variation principle, the boundary conditions. Using our covariant Hamiltonian formalism, we found four particular quasilocal energy-momentum boundary term expressions; each corresponds to a physically distinct and geometrically clear boundary condition. Here, from a consideration of the asymptotics, we show how a fundamental Hamiltonian identity naturally leads to the associated quasilocal energy flux expressions. For electromagnetism one of the four is distinguished: the only one which is gauge invariant; it gives the familiar energy density and Poynting flux. For Einstein's general relativity two different boundary condition choices correspond to quasilocal expressions which asymptotically give the ADM energy, the Trautman-Bondi energy and, moreover, an associated energy flux (both outgoing and incoming). Again there is a distinguished expression: the one which is covariant

  1. Short-term plasticity in auditory cognition.

    Science.gov (United States)

    Jääskeläinen, Iiro P; Ahveninen, Jyrki; Belliveau, John W; Raij, Tommi; Sams, Mikko

    2007-12-01

    Converging lines of evidence suggest that auditory system short-term plasticity can enable several perceptual and cognitive functions that have been previously considered as relatively distinct phenomena. Here we review recent findings suggesting that auditory stimulation, auditory selective attention and cross-modal effects of visual stimulation each cause transient excitatory and (surround) inhibitory modulations in the auditory cortex. These modulations might adaptively tune hierarchically organized sound feature maps of the auditory cortex (e.g. tonotopy), thus filtering relevant sounds during rapidly changing environmental and task demands. This could support auditory sensory memory, pre-attentive detection of sound novelty, enhanced perception during selective attention, influence of visual processing on auditory perception and longer-term plastic changes associated with perceptual learning.

  2. The term structure of oil futures prices

    International Nuclear Information System (INIS)

    Gabillon, J.

    1991-01-01

    In recent years, there has been a massive development of derivative financial products in oil markets. The main interest came from large energy end-users who found in them a welcome opportunity to lock in fixed or maximum prices for their supplies over a period of time. Oil companies and oil traders were able to provide tailor-made swaps or options for the specific needs of the end-users. In this paper, we present a two-variable model of the term structures of futures prices and volatilities assuming that the spot and long-term prices of oil are stochastic, and are the main determinants of the convenience yield function. Although the resulting convenience yield is stochastic, the model admits an analytic formulation under some restrictions. (author)

  3. Long term economic relationships from cointegration maps

    Science.gov (United States)

    Vicente, Renato; Pereira, Carlos de B.; Leite, Vitor B. P.; Caticha, Nestor

    2007-07-01

    We employ the Bayesian framework to define a cointegration measure aimed to represent long term relationships between time series. For visualization of these relationships we introduce a dissimilarity matrix and a map based on the sorting points into neighborhoods (SPIN) technique, which has been previously used to analyze large data sets from DNA arrays. We exemplify the technique in three data sets: US interest rates (USIR), monthly inflation rates and gross domestic product (GDP) growth rates.

  4. Murine model of long term obstructive jaundice

    Science.gov (United States)

    Aoki, Hiroaki; Aoki, Masayo; Yang, Jing; Katsuta, Eriko; Mukhopadhyay, Partha; Ramanathan, Rajesh; Woelfel, Ingrid A.; Wang, Xuan; Spiegel, Sarah; Zhou, Huiping; Takabe, Kazuaki

    2016-01-01

    Background With the recent emergence of conjugated bile acids as signaling molecules in cancer, a murine model of obstructive jaundice by cholestasis with long-term survival is in need. Here, we investigated the characteristics of 3 murine models of obstructive jaundice. Methods C57BL/6J mice were used for total ligation of the common bile duct (tCL), partial common bile duct ligation (pCL), and ligation of left and median hepatic bile duct with gallbladder removal (LMHL) models. Survival was assessed by Kaplan-Meier method. Fibrotic change was determined by Masson-Trichrome staining and Collagen expression. Results 70% (7/10) of tCL mice died by Day 7, whereas majority 67% (10/15) of pCL mice survived with loss of jaundice. 19% (3/16) of LMHL mice died; however, jaundice continued beyond Day 14, with survival of more than a month. Compensatory enlargement of the right lobe was observed in both pCL and LMHL models. The pCL model demonstrated acute inflammation due to obstructive jaundice 3 days after ligation but jaundice rapidly decreased by Day 7. The LHML group developed portal hypertension as well as severe fibrosis by Day 14 in addition to prolonged jaundice. Conclusion The standard tCL model is too unstable with high mortality for long-term studies. pCL may be an appropriate model for acute inflammation with obstructive jaundice but long term survivors are no longer jaundiced. The LHML model was identified to be the most feasible model to study the effect of long-term obstructive jaundice. PMID:27916350

  5. Long-term economic outlook. Annual review

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    This review provides economic growth forecast tables for Ontario, Canada, the US, Western Europe, and Japan. Economic growth, government policy, the long-term prospects for inflation, interest rates and foreign exchange rates, trends in the Canadian dollar, and energy markets and prices are also reviewed. Data generally cover 1965-2025. Appendices give a summary of historical and forecast data. 18 figs., 16 tabs.

  6. The 2015 Long-term Budget Outlook

    Science.gov (United States)

    2015-06-01

    certain employment -based health insurance plans with high premiums, scheduled to go into effect in 2018 as a result of the ACA , will be implemented...from now would have a smaller negative effect on output and employment in the short term. However, waiting for some time before reducing spending...reductions in federal spending or increases in taxes that were implemented several years from now would have a smaller effect on output and employment in

  7. Reevaluation of HFIR source term: Supplement 2

    International Nuclear Information System (INIS)

    Thomas, W.E.

    1986-11-01

    The HFIR source term has been reevaluated to assess the impact of the increase in core lifetime from 15 to 24 days. Calculations were made to determine the nuclide activities of the iodines, noble gases, and other fission products. The results show that there is no significant change in off-site dose due to the increased fuel cycle for the release scenario postulated in ORNL-3573

  8. Quadratic Term Structure Models in Discrete Time

    OpenAIRE

    Marco Realdon

    2006-01-01

    This paper extends the results on quadratic term structure models in continuos time to the discrete time setting. The continuos time setting can be seen as a special case of the discrete time one. Recursive closed form solutions for zero coupon bonds are provided even in the presence of multiple correlated underlying factors. Pricing bond options requires simple integration. Model parameters may well be time dependent without scuppering such tractability. Model estimation does not require a r...

  9. Long-term data storage in diamond

    OpenAIRE

    Dhomkar, Siddharth; Henshaw, Jacob; Jayakumar, Harishankar; Meriles, Carlos A.

    2016-01-01

    The negatively charged nitrogen vacancy (NV?) center in diamond is the focus of widespread attention for applications ranging from quantum information processing to nanoscale metrology. Although most work so far has focused on the NV? optical and spin properties, control of the charge state promises complementary opportunities. One intriguing possibility is the long-term storage of information, a notion we hereby introduce using NV-rich, type 1b diamond. As a proof of principle, we use multic...

  10. French Approach for Long Term Storage Safety

    International Nuclear Information System (INIS)

    Marciano, Jacob; Carreton, Jean-Pierre; Lizot, Marie Therese; Lhomme, Veronique

    2014-01-01

    IRSN presents its statement regarding long-term storage facilities; in France, the regulatory documents do not define the long term duration. The storage facility lifetime can only be appreciated according to the needs and materials stored therein. However, the magnitude of the long-term can be estimated at a few hundred years compared to a few decades for current storage. Usually, in France, construction of storage facilities is driven from the necessity various necessities, linked to the management of radioactive material (eg spent fuel) and to the management of radioactive waste. Because of the variety of 'stored materials and objects' (fission product solutions, plutonium oxide powders, activated solids, drums containing technological waste, spent fuel...), a great number of storage facility design solutions have been developed (surface, subsurface areas, dry or wet conditions...) in the World. After describing the main functions of a storage facility, IRSN displays the safety principles and the associated design principles. The specific design principles applied to particular storage (dry or wet spent fuel storage, depleted uranium or reprocessed uranium storage, plutonium storage, waste containing tritium storage, HLW and ILLW storage...) are also presented. Finally, the concerns due to the long-term duration storage and related safety assessment are developed. After discussing these issues, IRSN displays its statement. The authorization procedures governing the facility lifetime are similar to those of any basic nuclear installation, the continuation of the facility operation remaining subject to periodic safety reviews (in France, every 10 years). The applicant safety cases have to show, that the safety requirements are always met; this requires, at minimum, to take into account at the design stage, comfortable design margins. (author)

  11. Accounting of Long-Term Biological Assets

    OpenAIRE

    Valeriy Mossakovskyy; Vasyl Korytnyy

    2015-01-01

    The article is devoted to generalization of experience in valuation of long-term biological assets of plant-growing and animal-breeding, and preparation of suggestions concerning improvement of accounting in this field. Recommendations concerning accounting of such assets are given based on the study of accounting practice at specific agricultural company during long period of time. Authors believe that fair value is applicable only if price level for agricultural products is fixed by the gov...

  12. Optimal long-term contracting with learning

    OpenAIRE

    He, Zhiguo; Wei, Bin; Yu, Jianfeng; Gao, Feng

    2016-01-01

    We introduce uncertainty into Holmstrom and Milgrom (1987) to study optimal long-term contracting with learning. In a dynamic relationship, the agent's shirking not only reduces current performance but also increases the agent's information rent due to the persistent belief manipulation effect. We characterize the optimal contract using the dynamic programming technique in which information rent is the unique state variable. In the optimal contract, the optimal effort is front-loaded and decr...

  13. Greek paideia and terms of probability

    Directory of Open Access Journals (Sweden)

    Fernando Leon Parada

    2016-06-01

    Full Text Available This paper addresses three aspects of the conceptual framework for a doctoral dissertation research in process in the field of Mathematics Education, in particular, in the subfield of teaching and learning basic concepts of Probability Theory at the College level. It intends to contrast, sustain and elucidate the central statement that the meanings of some of these basic terms used in Probability Theory were not formally defined by any specific theory but relate to primordial ideas developed in Western culture from Ancient Greek myths. The first aspect deals with the notion of uncertainty, with that Greek thinkers described several archaic gods and goddesses of Destiny, like Parcas and Moiras, often personified in the goddess Tyche—Fortuna for the Romans—, as regarded in Werner Jaeger’s “Paideia”. The second aspect treats the idea of hazard from two different approaches: the first approach deals with hazard, denoted by Plato with the already demythologized term ‘tyche’ from the viewpoint of innate knowledge, as Jaeger points out. The second approach deals with hazard from a perspective that could be called “phenomenological”, from which Aristotle attempted to articulate uncertainty with a discourse based on the hypothesis of causality. The term ‘causal’ was opposed both to ‘casual’ and to ‘spontaneous’ (as used in the expression “spontaneous generation”, attributing uncertainty to ignorance of the future, thus respecting causal flow. The third aspect treated in the paper refers to some definitions and etymologies of some other modern words that have become technical terms in current Probability Theory, confirming the above-mentioned main proposition of this paper.

  14. Inflation Hedging for Long-Term Investors

    OpenAIRE

    Shaun K. Roache; Alexander P. Attie

    2009-01-01

    Long-term investors face a common problem-how to maintain the purchasing power of their assets over time and achieve a level of real returns consistent with their investment objectives. While inflation-linked bonds and derivatives have been developed to hedge the effects of inflation, their limited supply and liquidity lead many investors to continue to rely on the indirect hedging properties of traditional asset classes. In this paper, we assess these properties over different time horizons,...

  15. Long term evolution 4G and beyond

    CERN Document Server

    Yacoub, Michel; Figueiredo, Fabrício; Tronco, Tania

    2016-01-01

    This book focus on Long Term Evolution (LTE) and beyond. The chapters describe different aspects of research and development in LTE, LTE-Advanced (4G systems) and LTE-450 MHz such as telecommunications regulatory framework, voice over LTE, link adaptation, power control, interference mitigation mechanisms, performance evaluation for different types of antennas, cognitive mesh network, integration of LTE network and satellite, test environment, power amplifiers and so on. It is useful for researchers in the field of mobile communications.

  16. Long-Term Care Services for Veterans

    Science.gov (United States)

    2017-02-14

    includes but is not limited to home physical , occupational, or speech therapy ; wound care; and intravenous (IV) care. A VA physician determines that a...restoring/rehabilitating the veteran’s health, such as skilled nursing care, physical therapy , occupational therapy , and IV therapy Same as HBPC... geriatric evaluation,  palliative care,  adult day health care,  homemaker/home health aide care,  respite care, Long-Term Care Services for

  17. A short-term neural network memory

    Energy Technology Data Exchange (ETDEWEB)

    Morris, R.J.T.; Wong, W.S.

    1988-12-01

    Neural network memories with storage prescriptions based on Hebb's rule are known to collapse as more words are stored. By requiring that the most recently stored word be remembered precisely, a new simple short-term neutral network memory is obtained and its steady state capacity analyzed and simulated. Comparisons are drawn with Hopfield's method, the delta method of Widrow and Hoff, and the revised marginalist model of Mezard, Nadal, and Toulouse.

  18. Long term adequacy of uranium resources

    International Nuclear Information System (INIS)

    Steyn, J.

    1990-01-01

    This paper examines the adequacy of world economic uranium resources to meet requirements in the very long term, that is until at least 2025 and beyond. It does so by analysing current requirements forecasts, existing and potential production centre supply capability schedules and national resource estimates. It takes into account lead times from resource discovery to production and production rate limitations. The institutional and political issues surrounding the question of adequacy are reviewed. (author)

  19. Lattice Paths and the Constant Term

    International Nuclear Information System (INIS)

    Brak, R; Essam, J; Osborn, J; Owczarek, A L; Rechnitzer, A

    2006-01-01

    We firstly review the constant term method (CTM), illustrating its combinatorial connections and show how it can be used to solve a certain class of lattice path problems. We show the connection between the CTM, the transfer matrix method (eigenvectors and eigenvalues), partial difference equations, the Bethe Ansatz and orthogonal polynomials. Secondly, we solve a lattice path problem first posed in 1971. The model stated in 1971 was only solved for a special case - we solve the full model

  20. Conversion of short-term to long-term memory in the novel object recognition paradigm.

    Science.gov (United States)

    Moore, Shannon J; Deshpande, Kaivalya; Stinnett, Gwen S; Seasholtz, Audrey F; Murphy, Geoffrey G

    2013-10-01

    It is well-known that stress can significantly impact learning; however, whether this effect facilitates or impairs the resultant memory depends on the characteristics of the stressor. Investigation of these dynamics can be confounded by the role of the stressor in motivating performance in a task. Positing a cohesive model of the effect of stress on learning and memory necessitates elucidating the consequences of stressful stimuli independently from task-specific functions. Therefore, the goal of this study was to examine the effect of manipulating a task-independent stressor (elevated light level) on short-term and long-term memory in the novel object recognition paradigm. Short-term memory was elicited in both low light and high light conditions, but long-term memory specifically required high light conditions during the acquisition phase (familiarization trial) and was independent of the light level during retrieval (test trial). Additionally, long-term memory appeared to be independent of stress-mediated glucocorticoid release, as both low and high light produced similar levels of plasma corticosterone, which further did not correlate with subsequent memory performance. Finally, both short-term and long-term memory showed no savings between repeated experiments suggesting that this novel object recognition paradigm may be useful for longitudinal studies, particularly when investigating treatments to stabilize or enhance weak memories in neurodegenerative diseases or during age-related cognitive decline. Copyright © 2013 Elsevier Inc. All rights reserved.