Mass and Charge in Brane-World and Non-Compact Kaluza-Klein Theories in 5 Dim
NASA Astrophysics Data System (ADS)
Ponce de Leon, J.
2003-08-01
In classical Kaluza-Klein theory, with compactified extra dimensions and without scalar field, the rest mass as well as the electric charge of test particles are constants of motion. We show that in the case of a large extra dimension this is no longer so. We propose the Hamilton-Jacobi formalism, instead of the geodesic equation, for the study of test particles moving in a five-dimensional background metric. This formalism has a number of advantages: (i) it provides a clear and invariant definition of rest mass, without the ambiguities associated with the choice of the parameters used along the motion in 5D and 4D, (ii) the electromagnetic field can be easily incorporated in the discussion, and (iii) we avoid the difficulties associated with the ``splitting'' of the geodesic equation. For particles moving in a general 5D metric, we show how the effective rest mass, as measured by an observer in 4D, varies as a consequence of the large extra dimension. Also, the fifth component of the momentum changes along the motion. This component can be identified with the electric charge of test particles. With this interpretation, both the rest mass and the charge vary along the trajectory. The constant of motion is now a combination of these quantities. We study the cosmological variations of charge and rest mass in a five-dimensional bulk metric which is used to embed the standard k = 0 FRW universes. The time variations in the fine structure ``constant'' and the Thomson cross section are also discussed.
Warped Kaluza-Klein reduction from string duality
NASA Astrophysics Data System (ADS)
Schulz, Michael; Tammaro, Elliott
2014-03-01
Virtually all phenomenologically relevant string theory compactifications are of warped type, in which the overall scale factor of 4D spacetime varies over the internal dimensions. However, the procedure for Kaluza-Klein (KK) reduction is more poorly understood for warped compactifications than for standard compactifications. The simplest standard compactifications are compactifications on tori, and the simplest warped compactifications differ from these by the addition of parallel D-branes and O-branes. It is astonishing that a direct derivation of the dimensionally reduced action does not exist even for these simple warped compactifications (which are T-dual to Type I), although the answer is known on supersymmetry grounds. We fill this void. We derive the procedure for the KK reduction of a simple Type IIA warped compactification with D6 branes and O6 planes, via its lift to the standard compactification of M-theory on K3. Our derivation utilizes an approximate K3 metric of Gibbons-Hawking form, which is exactly equivalent to the classical type IIA supergravity description of the warped compactification. This material is based upon work supported by the National Science Foundation under Grant Nos. PHY09-12219 and PHY11-25915.
Kaluza's and Klein's Contributions to the Kaluza-Klein-Theory
NASA Astrophysics Data System (ADS)
Wünsch, Daniela; Goenner, Hubert
2006-02-01
Kaluza's and Klein's contributions to Kaluza-Klein-theory. The Kaluza-Klein-theory is one of the "classics" of modern theoretical physics. All theories that construct a space with extra dimensions, such as superstring and membrane theory, are based on the structure of this unified theory. The original five-dimensional theories by Theodor Kaluza (from 1921) and Oskar Klein (from 1926) have not yet been closely analysed, historically. What has survived as an established part of physics is a "folklore version" that mixes together elements from both theories. Our paper analyses the individual mathematical and physical contributions by Kaluza and Klein. It points out the importance of the achievements of these two founders of five-dimensional unified theories, and compares them with the folklore version of the Kaluza-Klein theory.
Kaluza-Klein Reduction of Pure Gravity and its Implications for K3 Surface Compactifications
NASA Astrophysics Data System (ADS)
Tammaro, Elliott
Kaluza demonstrated that a geometrical unification of Einsteinian gravity and Maxwell's equations could occur in five (4+1) dimensions if the dependence on the fourth spatial coordinate is ignorable. Klein noted that the last assumption would be natural for a compact extra dimension (i.e., a circle, rather than a line) of very small size. Since this initial proposal dimensional reduction has been incorporated into string theory, where the compactification manifold of choice is a Calabi-Yau manifold. In this dissertation, we investigate reduction via the Kaluza-Klein mechanism by considering the general compactification from D to d (D>d) dimensions of pure gravity, wherein the internal metric moduli are promoted to moduli fields. An essential point is that D-dimensional equations of motion must be satisfied, even in the effective degrees of freedom (the moduli fields). If the d-dimensional equations of motion imply the D-dimensional equations the effective theory is consistent. As a first pass the truncation to massless modes is made, but with a special gauge choice, transverse/traceless gauge, imposed on the internal metric. Equivalently, compensating fields, which are intended to assure consistency, are included in the metric ansatz. It is concluded that the consistency of the compactification demands that all massless and massive Kaluza-Klein modes be included in the lower dimensional theory. Motivated by the importance and ubiquitousness of K3 compactifications, a review of K3 geometry is presented. The E8 ⊕ E 8 ⊕ U31,1 and Sp(32)/Z2 ⊕ U 31,1 decompositions of the (co)homology lattice of the K3 are exhibited explicitly in terms of a natural orbifold basis, which augments the abstract derivations available in the literature. A novel feature is introduced -- an approximate, but explicit, metric on K3, which exactly generates a K3 metric in the limit of small fiber and large base.
Dimensional reduction of the 5D Kaluza-Klein geodesic deviation equation
NASA Astrophysics Data System (ADS)
Lacquaniti, V.; Montani, Giovanni; Vietri, F.
2010-02-01
In the work of Kerner et al. (Phys Rev D 63:027502, 2001) the problem of the geodesic deviation in a 5D Kaluza-Klein background is faced. The 4D space-time projection of the resulting equation coincides with the usual geodesic deviation equation in the presence of the Lorenz force, provided that the fifth component of the deviation vector satisfies an extra constraint which takes into account the q/ m conservation along the path. The analysis was performed setting as a constant the scalar field which appears in Kaluza-Klein model. Here we focus on the extension of such a work to the model where the presence of the scalar field is considered. Our result coincides with that of Kerner et al. when the minimal case {φ=1} is considered, while it shows some departures in the general case. The novelty due to the presence of {φ} is that the variation of the q/ m between the two geodesic lines is not conserved during the motion; an exact law for such a behaviour has been derived.
Kaluza-Klein nature of entropy function
NASA Astrophysics Data System (ADS)
Salti, Mustafa; Aydogdu, Oktay; Yanar, Hilmi
2015-11-01
In the present study, we mainly investigate the nature of entropy function in non-flat Kaluza-Klein universe. We prove that the first and generalized second laws of gravitational thermodynamics are valid on the dynamical apparent horizon.
Klein-Gordon oscillator in Kaluza-Klein theory
NASA Astrophysics Data System (ADS)
Carvalho, Josevi; Carvalho, Alexandre M. de M.; Cavalcante, Everton; Furtado, Claudio
2016-07-01
In this contribution we study the Klein-Gordon oscillator on the curved background within the Kaluza-Klein theory. The problem of the interaction between particles coupled harmonically with topological defects in Kaluza-Klein theory is studied. We consider a series of topological defects, then we treat the Klein-Gordon oscillator coupled to this background, and we find the energy levels and corresponding eigenfunctions in these cases. We show that the energy levels depend on the global parameters characterizing these spacetimes. We also investigate a quantum particle described by the Klein-Gordon oscillator interacting with a cosmic dislocation in Som-Raychaudhuri spacetime in the presence of homogeneous magnetic field in a Kaluza-Klein theory. In this case, the energy spectrum is determined, and we observe that these energy levels represent themselves as the sum of the terms related with Aharonov-Bohm flux and of the parameter associated to the rotation of the spacetime.
Vacuum destabilization from Kaluza Klein modes in an inflating brane
NASA Astrophysics Data System (ADS)
Pujolàs, Oriol; Sasaki, Misao
2005-09-01
We discuss the effects from the Kaluza Klein modes in the brane world scenario when an interaction between bulk and brane fields is included. We focus on the bulk inflaton model, where a bulk field Ψ drives inflation in an almost AdS5 bulk bounded by an inflating brane. We couple Ψ to a brane scalar field phiv representing matter on the brane. The bulk field Ψ is assumed to have a light mode, whose mass depends on the expectation value of phiv. The KK modes form a continuum with masses m>3H/2, where H is the Hubble constant. To estimate their effects, we integrate them out and obtain the 1-loop effective potential Veff(phiv). With no tuning of the parameters of the model, the vacuum becomes (meta)stable—Veff(phiv) develops a true vacuum at \\varphi \
Charged rotating dilaton black holes with Kaluza-Klein asymptotics
NASA Astrophysics Data System (ADS)
Knoll, Christian; Nedkova, Petya
2016-03-01
We construct a class of stationary and axisymmetric solutions to the five-dimensional Einstein-Maxwell-dilaton gravity, which describe configurations of charged rotating black objects with Kaluza-Klein asymptotics. The solutions are constructed by uplifting a vacuum seed solution to six dimensions, performing a boost and a subsequent circle reduction. We investigate the physical properties of the charged solutions and obtain their general relations to the properties of the vacuum seed. We also derive the gyromagnetic ratio and the Smarr-like relations. As particular cases, we study three solutions, which describe a charged rotating black string, a charged rotating black ring on Kaluza-Klein bubbles, and a superposition of two black holes and a Kaluza-Klein bubble.
Cosmological production of Kaluza-Klein monopoles
Harvey, J.A.; Kolb, E.W.; Perry, M.J.
1984-09-01
The cosmological production of Kaluza-Klein monopoles is discussed. The present monopole to entropy ratio is calculated in some simple models with the conclusion that this ratio is unacceptably large unless additional mechanisms for entropy production or monopole annihilation are present.
Einstein-Rosen solutions from Kaluza-Klein theory
NASA Astrophysics Data System (ADS)
López, L. A.; Bretón, N.; Ramírez, B. V.
2013-01-01
From a time-dependent boost-rotational symmetric vacuum solution of the Einstein Equations in five dimensions, through the Kaluza-Klein reduction the corresponding Einstein-Maxwell-dilaton solutions are obtained. The four dimensional counterpart turns out to be generalized Einstein-Rosen spacetimes representing unpolarized gravitational waves traveling in an inhomogeneous cosmology. Restricting the parameters we are able to obtain different 4D time-dependent solutions equipped with scalar and electromagnetic fields.
On the extra force in brane world scenario
NASA Astrophysics Data System (ADS)
Bejancu, Aurel; Farran, Hani Reda
2014-09-01
In the study of the dynamics in a 5D bulk from brane world scenario, an extra force with abnormal properties was detected (cf. [D. Youm, Extra force in brane worlds, Phys. Rev. D62 (2000) 084002; D. Youm, Null geodesics in brane world universe, Mod. Phys. Lett. A16 (2001) 2371; L. F. Zhang and Y. Z. Zhang, Null geodesics in brane world scenarios, Commun. Theor. Phys. (Beijing)41 (2004) 48]). In this paper, by using the Riemannian horizontal connection introduced in [A. Bejancu, A new point of view on general Kaluza-Klein theories, Progr. Theor. Phys.128 (2012) 541], we give a new definition for the extra force in a 5D bulk, and show that it does not contradict the 4D physics. In particular, we show that this force appears very rarely along geodesics in a warped 5D bulk.
Galactic entropy in extended Kaluza-Klein cosmology
NASA Astrophysics Data System (ADS)
Yanar, Hilmi; Salti, Mustafa; Aydogdu, Oktay; Acikgoz, Irfan; Yasar, Erol
2016-02-01
We use a Kaluza-Klein model with variable cosmological and gravitational terms to discuss the nature of galactic entropy function. For this purpose, we assume a universe filled with dark fluid and consider five-dimensional (5D) field equations using the Gamma law equation. We mainly discuss the validity of the first and generalized second laws of galactic thermodynamics for viable Kaluza-Klein models.
A neo-intuitive proposal for Kaluza-Klein unification
NASA Astrophysics Data System (ADS)
Rosen, Steven M.
1988-11-01
This paper addresses a central question of contemporary theoretical physics: Can a unified account be provided for the known forces of nature? The issue is brought into focus by considering the recently revived Kaluza-Klein approach to unification, a program entailing dimensional transformation through cosmogony. First it is demonstrated that, in a certain sence, revitalized Kaluza-Klein theory appears to undermine the intuitive foundations of mathematical physics, but that this implicit consequence has been repressed at a substantial cost. A fundamental reformulation of the Kaluza-Klein strategy is then undertaken, one that casts it within a new intuitive context. This is followed by a provisional application of the suggested approach to the specific problem of cosmological change. The paper concludes by exploring the far-reaching epistemological implications of the “neo-intuitive” proposal set forth.
Hawking radiation as tunneling from squashed Kaluza-Klein black hole
Matsuno, Ken; Umetsu, Koichiro
2011-03-15
We discuss Hawking radiation from a five-dimensional squashed Kaluza-Klein black hole on the basis of the tunneling mechanism. A simple method, which was recently suggested by Umetsu, may be used to extend the original derivation by Parikh and Wilczek to various black holes. That is, we use the two-dimensional effective metric, which is obtained by the dimensional reduction near the horizon, as the background metric. Using the same method, we derive both the desired result of the Hawking temperature and the effect of the backreaction associated with the radiation in the squashed Kaluza-Klein black hole background.
Neutrinos from Kaluza-Klein dark matter in the Sun
Blennow, Mattias; Melbéus, Henrik; Ohlsson, Tommy E-mail: melbeus@kth.se
2010-01-01
We investigate indirect neutrino signals from annihilations of Kaluza-Klein dark matter in the Sun. Especially, we examine a five- as well as a six-dimensional model, and allow for the possibility that boundary localized terms could affect the spectrum to give different lightest Kaluza-Klein particles, which could constitute the dark matter. The dark matter candidates that are interesting for the purpose of indirect detection of neutrinos are the first Kaluza-Klein mode of the gauge boson and the neutral component of the gauge bosons. Using the DarkSUSY and WimpSim packages, we calculate muon fluxes at an Earth-based neutrino telescope, such as IceCube. For the five-dimensional model, the results that we obtained agree reasonably well with the results that have previously been presented in the literature, whereas for the six-dimensional model, we find that, at tree-level, the results are the same as for the five-dimensional model. Finally, if the first Kaluza-Klein mode of the gauge boson constitutes the dark matter, IceCube can constrain the parameter space. However, in the case that the neutral component of the gauge bosons is the LKP, the signal is too weak to be observed.
Non-oscillatory behaviour in vacuum Kaluza-Klein cosmologies
NASA Astrophysics Data System (ADS)
Demaret, J.; Henneaux, M.; Spindel, P.; Taormina, A.; Hanquin, J.-L.
The generic behavior of vacuum inhomogeneous Kaluza-Klein cosmologies is studied in the vicinity of the cosmological singularity. It is argued that, in spacetime dimensions equal to or greater than 11, the generalized Kasner solution, with monotonic power-law behavior of the spatial distances, becomes a general solution of the Einstein vacuum field equations and, moreover, the chaotic oscillatory behavior disappears.
Kaluza-Klein Braneworld Cosmology with Static Internal Dimensions
NASA Astrophysics Data System (ADS)
Kanno, S.; Langlois, D.; Sasaki, M.; Soda, J.
2007-10-01
We investigate the Kaluza-Klein braneworld cosmology from the point of view of observers on the brane. We first generalize the Shiromizu-Maeda-Sasaki (SMS) equations to higher dimensions. As an application, we study a (4+n)-dimensional brane with n dimensions compactified on the brane, in a (5+n)-dimensional bulk. By assuming that the size of the internal space is static, that the bulk energy-momentum tensor can be ignored, we determine the effect of the bulk geometry on the Kaluza-Klein braneworld. Then we derive the effective Friedmann equation on the brane. It turns out that the Friedmann equation explicitly depends on the equation of state, in contrast to the braneworld in a 5-dimensional bulk spacetime. In particular, in a radiation-dominated era, the effective Newton constant depends logarithmically on the scale factor. If we include a pressureless matter on the brane, this dependence disappears after the radiation-matter equality. This may be interpreted as st abilization of the Newton constant by the matter on the brane. Our findings imply that the Kaluza-Klein braneworld cosmology is quite different from the conventional Kaluza-Klein cosmology even at low energy.
Geodetic precession in squashed Kaluza-Klein black hole spacetimes
Matsuno, Ken; Ishihara, Hideki
2009-11-15
We investigate the geodetic precession effect of a parallelly transported spin vector along a circular geodesic in five-dimensional squashed Kaluza-Klein black hole spacetime. Then we derive the higher-dimensional correction of the precession angle to general relativity. We find that the correction is proportional to the square of (size of extra dimension)/(gravitational radius of central object)
Confining the scalar field of the Kaluza-Klein wormhole soliton
Clement, G. )
1989-08-01
The Maison five-to-three dimensional reduction, generalized to the case of five-dimensional general relativity with sources, is applied to the problem of confining the scalar field of the Kaluza-Klein wormhole soliton by a very weak perfect fluid source, without affecting the spatial geometry of this localized solution.
Residue theorem and summing over Kaluza-Klein excitations
Feng Taifu; Chen Jianbin; Gao Tiejun; Sun Kesheng
2011-11-01
Applying the equations of motion together with corresponding boundary conditions of bulk profiles at infrared and ultraviolet branes, we verify some lemmas on the eigenvalues of Kaluza-Klein modes in extension of the standard model with a warped extra dimension and the custodial symmetry SU(3){sub c}xSU(2){sub L}xSU(2){sub R}xU(1){sub X}xP{sub LR}. Using the lemmas and performing properly analytic extensions of bulk profiles, we present the sufficient condition for a convergent series of Kaluza-Klein excitations and sum over the series through the residue theorem. The method can also be applied to sum over the infinite series of Kaluza-Klein excitations in a universal extra dimension. Furthermore, we analyze the possible connection between the propagators in five-dimensional full theory and the product of bulk profiles with corresponding propagators of exciting Kaluza-Klein modes in four-dimensional effective theory, and recover some relations presented in the literature for warped and universal extra dimensions, respectively. As an example, we present the correction from new physics to the branching ratio of B{yields}X{sub s{gamma}} to the order O({mu}{sub EW}{sup 2}/{Lambda}{sub KK}{sup 2}) in extension of the standard model with a warped extra dimension and the custodial symmetry, where {Lambda}{sub KK} denotes the energy scale of low-lying Kaluza-Klein excitations and {mu}{sub EW} denotes the electroweak energy scale.
Charged rotating Kaluza-Klein black holes in dilaton gravity
Allahverdizadeh, Masoud; Matsuno, Ken; Sheykhi, Ahmad
2010-02-15
We obtain a class of slowly rotating charged Kaluza-Klein black hole solutions of the five-dimensional Einstein-Maxwell-dilaton theory with arbitrary dilaton coupling constant. At infinity, the spacetime is effectively four dimensional. In the absence of the squashing function, our solution reduces to the five-dimensional asymptotically flat slowly rotating charged dilaton black hole solution with two equal angular momenta. We calculate the mass, the angular momentum, and the gyromagnetic ratio of these rotating Kaluza-Klein dilaton black holes. It is shown that the dilaton field and the nontrivial asymptotic structure of the solutions modify the gyromagnetic ratio of the black holes. We also find that the gyromagnetic ratio crucially depends on the dilaton coupling constant, {alpha}, and decreases with increasing {alpha} for any size of the compact extra dimension.
On the stability of toroidally compact Kaluza-Klein theories
NASA Astrophysics Data System (ADS)
Blau, S. K.; Guendelman, E. I.; Taormina, A.; Wijewardhana, L. C. R.
1984-08-01
We study the stability ar the one loop level, of finite temperature Kaluza-Klein theories coupled to matter fields. We restrict our attention to space-times containing compact manifolds which are toruses and Klein bottles. If the cosmological constant is chosen so that the effective potential vanishes at its minimum, and if twisted bosons or untwisted fermions are introduced into the theory, then these space-times are stable below a critical temperature of the order of the particle masses. We also discuss some subtleties that arises when Fermi fields are defined on non-simply connected manifolds.
Towards Kaluza-Klein Dark Matter on nilmanifolds
NASA Astrophysics Data System (ADS)
Andriot, David; Cacciapaglia, Giacomo; Deandrea, Aldo; Deutschmann, Nicolas; Tsimpis, Dimitrios
2016-06-01
We present a first study of the field spectrum on a class of negatively-curved compact spaces: nilmanifolds or twisted tori. This is a case where analytical results can be obtained, allowing to check numerical methods. We focus on the Kaluza-Klein expansion of a scalar field. The results are then applied to a toy model where a natural Dark Matter candidate arises as a stable massive state of the bulk scalar.
Constraints on cosmic superstrings from Kaluza-Klein emission.
Dufaux, Jean-François
2012-07-01
Cosmic superstrings interact generically with a tower of light and/or strongly coupled Kaluza-Klein (KK) modes associated with the geometry of the internal space. We study the production of KK particles by cosmic superstring loops, and show that it is constrained by big bang nucleosynthesis. We study the resulting constraints in the parameter space of the underlying string theory model and highlight their complementarity with the regions that can be probed by current and upcoming gravitational wave experiments. PMID:23031097
Finite Number of Kaluza-Klein Modes, all with Zero Masses
NASA Astrophysics Data System (ADS)
Erdem, Recai
Kaluza-Klein modes of fermions in a five-dimensional toy model are considered. The number of Kaluza-Klein modes that survive after integration over extra dimensions is finite in this space. Moreover, the extra dimensional piece of the kinetic part of the Lagrangian in this space induces no mass for the higher Kaluza-Klein modes on contrary to the standard lore.
Fermions in five-dimensional brane world models
NASA Astrophysics Data System (ADS)
Smolyakov, Mikhail N.
2016-06-01
In the present paper the fermion fields, living in the background of five-dimensional warped brane world models with compact extra dimension, are thoroughly examined. The Kaluza-Klein decomposition and isolation of the physical degrees of freedom is performed for those five-dimensional fermion field Lagrangians, which admit such a decomposition to be performed in a mathematically consistent way and provide a physically reasonable four-dimensional effective theory. It is also shown that for the majority of five-dimensional fermion field Lagrangians there are no (at least rather obvious) ways to perform the Kaluza-Klein decomposition consistently. Moreover, in these cases one may expect the appearance of various pathologies in the four-dimensional effective theory. Among the cases, for which the Kaluza-Klein decomposition can be performed in a mathematically consistent way, the case, which reproduces the Standard Model by the zero Kaluza-Klein modes most closely regardless of the size of the extra dimension, is examined in detail in the background of the Randall-Sundrum model.
Universal extra dimension: Violation of Kaluza-Klein parity
Bhattacherjee, Biplob
2009-01-01
The minimal universal extra dimension (mUED) model respects the Kaluza-Klein (KK) parity (-1){sup n}, where n is the KK number. However, it is possible to have interactions located at only one of the two fixed points of the S{sub 1}/Z{sub 2} orbifold. Such asymmetric interactions violate the KK parity. This kills the cold dark matter component of UED but also removes the upper bound on the inverse compactification radius, and thus nonobservation of the KK excitations even at the Large Hadron Collider does not necessarily invalidate the model. Apart from the decay of the lightest n=1 KK excitation, this leads to collider signals which are markedly different from those in the mUED scenario. The phenomenological consequences of such KK-parity violating terms are explored.
Generalized Kaluza-Klein monopole, quadratic algebras and ladder operators
NASA Astrophysics Data System (ADS)
Marquette, Ian
2011-06-01
We present a generalized Kaluza-Klein monopole system. We solve this quantum superintegrable system on a Euclidean Taub Nut manifold using the separation of variables of the corresponding Schrödinger equation in spherical and parabolic coordinates. We present the integrals of motion of this system, the quadratic algebra generated by these integrals, the realization in terms of a deformed oscillator algebra using the Daskaloyannis construction and the energy spectrum. The structure constants and the Casimir operator are functions not only of the Hamiltonian but also of other two integrals commuting with all generators of the quadratic algebra and forming an Abelian subalgebra. We present another algebraic derivation of the energy spectrum of this system using the factorization method and ladder operators.
Charged rotating Kaluza-Klein black holes in five dimensions
Nakagawa, Toshiharu; Ishihara, Hideki; Matsuno, Ken; Tomizawa, Shinya
2008-02-15
We construct a new charged rotating Kaluza-Klein black hole solution in the five-dimensional Einstein-Maxwell theory with a Chern-Simon term. The features of the solutions are also investigated. The spacetime is asymptotically locally flat, i.e., it asymptotes to a twisted S{sup 1} bundle over the four-dimensional Minkowski spacetime. The solution describe a non-BPS black hole rotating in the direction of the extra dimension. The solutions have the limits to the supersymmetric black hole solutions, a new extreme non-BPS black hole solution and a new rotating non-BPS black hole solution with a constant twisted S{sup 1} fiber.
The abundance of Kaluza-Klein dark matter with coannihilation
Burnell, Fiona; Kribs, Graham D.
2006-01-01
In universal extra dimension models, the lightest Kaluza-Klein (KK) particle is generically the first KK excitation of the photon and can be stable, serving as particle dark matter. We calculate the thermal relic abundance of the KK photon for a general mass spectrum of KK excitations including full coannihilation effects with all (level-one) KK excitations. We find that including coannihilation can significantly change the relic abundance when the coannihilating particles are within about 20% of the mass of the KK photon. Matching the relic abundance with cosmological data, we find the mass range of the KK photon is much wider than previously found, up to about 2 TeV if the masses of the strongly interacting level-one KK particles are within 5% of the mass of the KK photon. We also find cases where several coannihilation channels compete (constructively and destructively) with one another. The lower bound on the KK photon mass, about 540 GeV when just right-handed KK leptons coannihilate with the KK photon, relaxes upward by several hundred GeV when coannihilation with electroweak KK gauge bosons of the same mass is included.
Cosmic super-strings and Kaluza-Klein modes
Dufaux, Jean-François
2012-09-01
Cosmic super-strings interact generically with a tower of relatively light and/or strongly coupled Kaluza-Klein (KK) modes associated with the geometry of the internal space. In this paper, we study the production of spin-2 KK particles by cusps on loops of cosmic F- and D-strings. We consider cosmic super-strings localized either at the bottom of a warped throat or in a flat internal space with large volume. The total energy emitted by cusps in KK modes is comparable in both cases, although the number of produced KK modes may differ significantly. We then show that KK emission is constrained by the photo-dissociation of light elements and by observations of the diffuse gamma ray background. We show that this rules out regions of the parameter space of cosmic super-strings that are complementary to the regions that can be probed by current and upcoming gravitational wave experiments. KK modes are also expected to play an important role in the friction-dominated epoch of cosmic super-string evolution.
The Equivalence Principle in Kaluza-Klein Gravity
NASA Astrophysics Data System (ADS)
Ponce de Leon, J.
In four-dimensional general relativity the space-time outside of an isolated spherical star is described by a unique line element, which is the Schwarzschild metric. As a consequence, the "gravitational" mass and the "inertial" mass of a star are equal to each other. However, theories that envision our world as being embedded in a larger universe, with more than four dimensions, permit a number of possible non-Schwarzschild 4D exteriors, which typically lead to different masses, violating the weak equivalence principle of ordinary general relativity. Therefore, the question arises as to whether the violation of this principle, i.e. the equality of gravitational and inertial mass, is a necessary consequence of the existence of extra dimensions. In this paper, in the context of Kaluza-Klein gravity in 5D, we show that the answer to this question is negative. We find a one-parameter family of asymptotically flat non-Schwarzschild static exteriors for which the inertial and gravitational masses are equal to each other, and equal to the Deser-Soldate mass. This family is consistent with the Newtonian weak field limit as well as with the general-relativistic Schwarzschild limit. Thus, we conclude that the existence of an extra dimension, and the corresponding non-Schwarzschild exterior, does not necessarily require different masses. However, to an observer in 4D, it does affect the motion of test particles in 4D, which is a consequence of the departure from the usual (4D) law of geodesic motion.
Measuring a Kaluza-Klein radius smaller than the Planck length
NASA Astrophysics Data System (ADS)
Reifler, Frank; Morris, Randall
2003-03-01
Hestenes has shown that a bispinor field on a Minkowski space-time is equivalent to an orthonormal tetrad of one-forms together with a complex scalar field. More recently, the Dirac and Einstein equations were unified in a tetrad formulation of a Kaluza-Klein model which gives precisely the usual Dirac-Einstein Lagrangian. In this model, Dirac’s bispinor equation is obtained in the limit for which the radius of higher compact dimensions of the Kaluza-Klein manifold becomes vanishingly small compared with the Planck length. For a small but finite radius, the Kaluza-Klein model predicts the velocity splitting of single fermion wave packets. That is, the model predicts that a single fermion wave packet will split into two wave packets with slightly different group velocities. The observation of such wave packet splits would determine the size of the Kaluza-Klein radius. If wave packet splits were not observed in experiments with currently achievable accuracies, the Kaluza-Klein radius would be bounded by at most 10-25 times the Planck length.
Kaluza-Klein models: Can we construct a viable example?
Eingorn, Maxim; Zhuk, Alexander
2011-02-15
In Kaluza-Klein models with toroidal compactification of the extra dimensions, we investigate soliton solutions of Einstein equation. The nonrelativistic gravitational potential of these solitons exactly coincides with the Newtonian one. We obtain the formulas for perihelion shift, deflection of light, time delay of radar echoes and post-Newtonian (PPN) parameters. Using the constraint on PPN parameter {gamma}, we find that the solitonic parameter k should be very big: |k|{>=}2.3x10{sup 4}. We define a soliton solution which corresponds to a pointlike mass source. In this case the soliton parameter k=2, which is clearly contrary to this restriction. A similar problem with the observations takes place for static spherically symmetric perfect fluid with the dustlike equation of state in all dimensions. The common for both of these models is the same (dustlike) equations of state in our three dimensions and in the extra dimensions. All dimensions are treated at equal footing. This is the crucial point. To be in agreement with observations, it is necessary to break the symmetry (in terms of equations of state) between the external/our and internal spaces. It takes place for black strings which are particular examples of solitons with k{yields}{infinity}. For such k, black strings are in concordance with the observations. Moreover, we show that they are the only solitons which are at the same level of agreement with the observations as in general relativity. Black strings can be treated as perfect fluid with dustlike equation of state p{sub 0}=0 in the external/our space and very specific equation of state p{sub 1}=-(1/2){epsilon} in the internal space. The latter equation is due to negative tension in the extra dimension. We also demonstrate that dimension 3 for the external space is a special one. Only in this case we get the latter equation of state. We show that the black string equations of state satisfy the necessary condition of the internal space stabilization
Detecting extra dimensions with gravity-wave spectroscopy: the black-string brane world.
Seahra, Sanjeev S; Clarkson, Chris; Maartens, Roy
2005-04-01
Using the black string between two branes as a model of a brane-world black hole, we compute the gravity-wave perturbations and identify the features arising from the additional polarizations of the graviton. The standard four-dimensional gravitational wave signal acquires late-time oscillations due to massive modes of the graviton. The Fourier transform of these oscillations shows a series of spikes associated with the masses of the Kaluza-Klein modes, providing in principle a spectroscopic signature of extra dimensions. PMID:15903904
On Pauli's Invention of Non-Abelian Kaluza-Klein Theory in 1953
NASA Astrophysics Data System (ADS)
Straumann, N.
2002-12-01
There are documents which show that Wolfgang Pauli developed in 1953 the first consistent generalization of the five-dimensional theory of Kaluza, Klein, Fock and others to a higher dimensional internal space. Because he saw no way to give masses to the gauge bosons, he refrained from publishing his results formally.
Z boson decay to photon plus Kaluza Klein graviton: large extra dimensional bounds
NASA Astrophysics Data System (ADS)
Allanach, B. C.; Skittrall, J. P.
2008-05-01
We consider the phenomenology of the decay of a Z boson into a photon and a Kaluza Klein excitation of the graviton in the ADD model. Using LEP data, we obtain an upper bound on the branching ratio corresponding to this process of ˜10-11. We also investigate energy profiles of the process.
Deformed phase space Kaluza-Klein cosmology and late time acceleration
NASA Astrophysics Data System (ADS)
Sabido, M.; Yee-Romero, C.
2016-06-01
The effects of phase space deformations on Kaluza-Klein cosmology are studied. The deformation is introduced by modifying the symplectic structure of the minisuperspace variables. In the deformed model, we find an accelerating scale factor and therefore infer the existence of an effective cosmological constant from the phase space deformation parameter β.
Hoop conjecture and the horizon formation cross section in Kaluza-Klein spacetimes
Yoo, Chul-Moon; Ishihara, Hideki; Kimura, Masashi; Tanzawa, Sugure
2010-01-15
We analyze momentarily static initial data sets of the gravitational field produced by two-point sources in five-dimensional Kaluza-Klein spacetimes. These initial data sets are characterized by the mass, the separation of sources and the size of an extra dimension. Using these initial data sets, we discuss the condition for black hole formation, and propose a new conjecture which is a hybrid of the four-dimensional hoop conjecture and the five-dimensional hyperhoop conjecture. By using the new conjecture, we estimate the cross section of black hole formation due to collisions of particles in Kaluza-Klein spacetimes. We show that the mass dependence of the cross section gives us information about the size and the number of the compactified extra dimensions.
Uniqueness theorem for Kaluza-Klein black holes in five-dimensional minimal supergravity
Tomizawa, Shinya
2010-11-15
We show a uniqueness theorem for Kaluza-Klein black holes in the bosonic sector of five-dimensional minimal supergravity. More precisely, under the assumptions of the existence of two commuting axial isometries and a nondegenerate connected event horizon of the cross-section topology S{sup 3}, or lens space, we prove that a stationary charged rotating Kaluza-Klein black hole in five-dimensional minimal supergravity is uniquely characterized by its mass, two independent angular momenta, electric charge, magnetic flux, and nut charge, provided that there exists neither a nut nor a bolt (a bubble) in the domain of outer communication. We also show that under the assumptions of the same symmetry, same asymptotics, and the horizon cross section of S{sup 1}xS{sup 2}, a black ring within the same theory--if it exists--is uniquely determined by its dipole charge and rod intervals besides the charges and magnetic flux.
NASA Astrophysics Data System (ADS)
Chakraborty, Shuvendu; Debnath, Ujjal; Jamil, Mubasher; Myrzakulov, Ratbay
2012-07-01
In this work, we have calculated the deceleration parameter, statefinder parameters and EoS parameters for different dark energy models with variable G correction in homogeneous, isotropic and non-flat universe for Kaluza-Klein Cosmology. The statefinder parameters have been obtained in terms of some observable parameters like dimensionless density parameter, EoS parameter and Hubble parameter for holographic dark energy, new agegraphic dark energy and generalized Chaplygin gas models.
Kaluza-Klein theory as a dynamics in a dual geometry
NASA Astrophysics Data System (ADS)
Gershon, Avi; Horwitz, Lawrence
2009-10-01
It has been shown that the orbits of motion for a wide class of nonrelativistic Hamiltonian systems can be described as geodesic flow on a manifold and an associated dual. This method can be applied to a four dimensional manifold of orbits in space-time associated with a relativistic system. One can study the consequences on the geometry of the introduction of electromagnetic interaction. We find that resulting geometrical structure in the dual space is that of Kaluza and Klein.
Z boson decay to photon plus Kaluza-Klein graviton in large extra dimensions
NASA Astrophysics Data System (ADS)
Allanach, Benjamin C.; Skittrall, Jordan P.; Sridhar, K.
2007-11-01
In the large extra dimensional ADD scenario, Z bosons undergo a one-loop decay into a photon and Kaluza-Klein towers of gravitons/gravi-scalars. We calculate such a decay width, extending previous arguments about the general form of the four-dimensional on-shell amplitude. The amplitudes calculated are relevant to processes in other extra dimensional models where the Standard Model fields are confined to a 4-brane.
The fate of the mixmaster behaviour in vacuum inhomogeneous Kaluza-Klein cosmological models
NASA Astrophysics Data System (ADS)
Demaret, Jacques; Hanquin, Jean-Luc; Henneaux, Marc; Spindel, Philipe; Taormina, Anne
1986-07-01
The generic behaviour of vacuum inhomogeneous Kaluza-Klein cosmologies is studied in the vicinity of the cosmological singularity. The collision law for the Kasner exponents is calculated in any number of spatial dimensions d. Its properties are investigated both theoretically and numerically. It is argued that the chaotic oscillatory behaviour disappears for d >= 10. This regime is replaced by the monotonic Kasner behaviour found previously.
NASA Astrophysics Data System (ADS)
García-Jiménez, I.; Novales-Sánchez, H.; Toscano, J. J.
2016-05-01
One-loop Standard Model observables produced by virtual heavy Kaluza-Klein fields play a prominent role in the minimal model of universal extra dimensions. Motivated by this aspect, we integrate out all the Kaluza-Klein heavy modes coming from the Yang-Mills theory set on a spacetime with an arbitrary number, n , of compact extra dimensions. After fixing the gauge with respect to the Kaluza-Klein heavy gauge modes in a covariant manner, we calculate a gauge-independent effective Lagrangian expansion containing multiple Kaluza-Klein sums that entail a bad divergent behavior. We use the Epstein-zeta function to regularize and characterize discrete divergences within such multiple sums, and then we discuss the interplay between the number of extra dimensions and the degree of accuracy of effective Lagrangians to generate or not divergent terms of discrete origin. We find that nonrenormalizable terms with mass dimension k are finite as long as k >4 +n . Multiple Kaluza-Klein sums of nondecoupling logarithmic terms, not treatable by Epstein-zeta regularization, are produced by four-dimensional momentum integration. On the grounds of standard renormalization, we argue that such effects are unobservable.
NASA Astrophysics Data System (ADS)
Maartens, Roy; Koyama, Kazuya
2010-09-01
The observable universe could be a 1+3-surface (the "brane") embedded in a 1+3+d-dimensional spacetime (the "bulk"), with Standard Model particles and fields trapped on the brane while gravity is free to access the bulk. At least one of the d extra spatial dimensions could be very large relative to the Planck scale, which lowers the fundamental gravity scale, possibly even down to the electroweak (˜TeV) level. This revolutionary picture arises in the framework of recent developments in M theory. The 1+10-dimensional M theory encompasses the known 1+9-dimensional superstring theories, and is widely considered to be a promising potential route to quantum gravity. At low energies, gravity is localized at the brane and general relativity is recovered, but at high energies gravity “leaks” into the bulk, behaving in a truly higher-dimensional way. This introduces significant changes to gravitational dynamics and perturbations, with interesting and potentially testable implications for high-energy astrophysics, black holes, and cosmology. Brane-world models offer a phenomenological way to test some of the novel predictions and corrections to general relativity that are implied by M theory. This review analyzes the geometry, dynamics and perturbations of simple brane-world models for cosmology and astrophysics, mainly focusing on warped 5-dimensional brane-worlds based on the Randall-Sundrum models. We also cover the simplest brane-world models in which 4-dimensional gravity on the brane is modified at low energies - the 5-dimensional Dvali-Gabadadze-Porrati models. Then we discuss co-dimension two branes in 6-dimensional models.
Rotating Kaluza-Klein multi-black holes with Goedel parameter
Matsuno, Ken; Ishihara, Hideki; Nakagawa, Toshiharu; Tomizawa, Shinya
2008-09-15
We obtain new five-dimensional supersymmetric rotating multi-Kaluza-Klein black hole solutions with the Goedel parameter in the Einstein-Maxwell system with a Chern-Simons term. These solutions have no closed timelike curve outside the black hole horizons. At infinity, the space-time is effectively four-dimensional. Each horizon admits various lens space topologies L(n;1)=S{sup 3}/Z{sub n} in addition to a round S{sup 3}. The space-time can have outer ergoregions disjointed from the black hole horizons, as well as inner ergoregions attached to each horizon. We discuss the rich structures of ergoregions.
NASA Astrophysics Data System (ADS)
Khudaverdian, H. M.
2014-03-01
We consider differential operators acting on densities of arbitrary weights on manifold M identifying pencils of such operators with operators on algebra of densities of all weights. This algebra can be identified with the special subalgebra of functions on extended manifold . On one hand there is a canonical lift of projective structures on M to affine structures on extended manifold . On the other hand the restriction of algebra of all functions on extended manifold to this special subalgebra of functions implies the canonical scalar product. This leads in particular to classification of second order operators with use of Kaluza-Klein-like mechanisms.
Entropy-corrected holographic scalar field models of dark energy in Kaluza-Klein universe
NASA Astrophysics Data System (ADS)
Sharif, M.; Jawad, Abdul
2013-12-01
We investigate the evolution of interacting holographic dark energy with logarithmic corrections in the flat Kaluza-Klein universe. We evaluate the equation of state parameter and also reconstruct the scalar field models in this scenario. For this purpose, the well-known choice of scale factor in the power law form is taken. It is interesting to mention here that the corresponding equation of state parameter crosses the phantom divide line for a particular choice of interacting parameters. Finally, we conclude that the behavior of the dynamical scalar field as well as the scalar potential is consistent with the present observations.
Hawking Radiation of the Charged Particle via Tunneling from the Kaluza-Klein Black Hole
NASA Astrophysics Data System (ADS)
Pu, Jin; Han, Yan
2016-08-01
In this paper, by applying the Lagrangian analysis on the action, we first redefine the geodesic equation of the charged massive particle. Then, basing on the new definition of the geodesic equation, we revisit the Hawking radiation of the charged massive particle via tunneling from the event horizon of the Kaluza-Klein black hole. In our treatment, the geodesic equation of the charged massive particle is defined uniformly with that of the massless particle, which overcomes the shortcomings of its previous definition, and is more suitable for the tunneling mechanism. The highlight of our work is a new and important development for the Parikh-Wilczek's tunneling method.
Compact hyperbolic extra dimensions: branes, kaluza-klein modes, and cosmology
Kaloper; March-Russell; Starkman; Trodden
2000-07-31
We reconsider theories with low gravitational (or string) scale M(*) where Newton's constant is generated via new large-volume spatial dimensions, while standard model states are localized to a 3-brane. Utilizing compact hyperbolic manifolds we show that the spectrum of Kaluza-Klein modes is radically altered. This allows the early Universe to evolve normally up to substantial temperatures, and completely negates the astrophysical constraints on M(*). Furthermore, an exponential hierarchy between the usual Planck scale and the true fundamental scale of physics can emerge with only O(1) coefficients. The linear size of the internal space remains small. The proposal has striking testable signatures. PMID:10991441
A 5D noncompact and non Ricci flat Kaluza-Klein Cosmology
NASA Astrophysics Data System (ADS)
Darabi, F.
2009-03-01
A model universe is proposed in the framework of 5D noncompact Kaluza-Klein cosmology which is not Ricci flat. The 4D part as the Robertson-Walker metric is coupled to conventional perfect fluid, and its extra-dimensional part is coupled to a dark pressure through a scalar field. It is shown that neither early inflation nor current acceleration of the 4D universe would happen if the nonvacuum states of the scalar field would contribute to 4D cosmology.
a 5d Noncompact Kaluza-Klein Cosmology in the Presence of Null Perfect Fluid
NASA Astrophysics Data System (ADS)
Farajollahi, Hossein; Amiri, Hamed
For the description of the early inflation and acceleration expansion of the universe that are compatible with observational data, the 5D noncompact Kaluza-Klein cosmology is investigated. It is proposed that the 5D space is filled with a null perfect fluid, resulting in a perfect fluid in a 4D universe, plus one along the fifth dimension. By analyzing the reduced field equations for the flat FRW model, we show the early inflationary behavior and the current acceleration of the universe.
Graviton Kaluza-Klein modes in nonflat branes with stabilized modulus
NASA Astrophysics Data System (ADS)
Paul, Tanmoy; SenGupta, Soumitra
2016-04-01
We consider a generalized two brane Randall-Sundrum model where the branes are endowed with nonzero cosmological constant. In this scenario, we re-examine the modulus stabilization mechanism and the nature of Kaluza-Klein (KK) graviton modes. Our result reveals that while the KK mode graviton masses may change significantly with the brane cosmological constant, the Goldberger-Wise stabilization mechanism, which assumes a negligible backreaction on the background metric, continues to hold even when the branes have a large cosmological constant. The possibility of having a global minimum for the modulus is also discussed. Our results also include an analysis for the radion mass in this nonflat brane scenario.
De Sitter brane-world, localization of gravity, and the cosmological constant
NASA Astrophysics Data System (ADS)
Neupane, Ishwaree P.
2011-04-01
Cosmological models with a de Sitter 3-brane embedded in a 5-dimensional de Sitter spacetime (dS5) give rise to a finite 4D Planck mass similar to that in Randall-Sundrum (RS) brane-world models in anti-de Sitter 5-dimensional spacetime(AdS5). Yet, there arise a few important differences as compared to the results with a flat 3-brane or 4D Minkowski spacetime. For example, the mass reduction formula (MRF) MPl2=M(5)3ℓAdS as well as the relationship MPl2=MPl(4+n)n+2Ln (with L being the average size or the radius of the n extra dimensions) expected in models of product-space (or Kaluza-Klein) compactifications get modified in cosmological backgrounds. In an expanding universe, a physically relevant MRF encodes information upon the 4-dimensional Hubble expansion parameter, in addition to the length and mass parameters L, MPl, and MPl(4+n). If a bulk cosmological constant is present in the solution, then the reduction formula is further modified. With these new insights, we show that the localization of a massless 4D graviton as well as the mass hierarchy between MPl and MPl(4+n) can be explained in cosmological brane-world models. A notable advantage of having a 5D de Sitter bulk is that in this case the zero-mass wave function is normalizable, which is not necessarily the case if the bulk spacetime is anti-de Sitter. In spacetime dimensions D≥7, however, the bulk cosmological constant Λb can take either sign (Λb<0, =0, or >0). The D=6 case is rather inconclusive, in which case Λb may be introduced together with 2-form gauge field (or flux). We obtain some interesting classical gravity solutions that compactify higher-dimensional spacetime to produce a Robertson-Walker universe with de Sitter-type expansion plus one extra noncompact direction. We also show that such models can admit both an effective 4-dimensional Newton constant that remains finite and a normalizable zero-mode graviton wave function.
Infinite-dimensional spin-2 symmetries in Kaluza-Klein theories
NASA Astrophysics Data System (ADS)
Hohm, Olaf
2006-02-01
We consider the couplings of an infinite number of spin-2 fields to gravity appearing in Kaluza-Klein theories. They are constructed as the broken phase of a massless theory possessing an infinite-dimensional spin-2 symmetry. Focusing on a circle compactification of four-dimensional gravity we show that the resulting gravity/spin-2 system in D=3 has in its unbroken phase an interpretation as a Chern-Simons theory of the Kac-Moody algebra iso(1,2)^ associated to the Poincaré group and also fits into the geometrical framework of algebra-valued differential geometry developed by Wald. Assigning all degrees of freedom to scalar fields, the matter couplings in the unbroken phase are determined, and it is shown that their global symmetry algebra contains the Virasoro algebra together with an enhancement of the Ehlers group SL(2,R) to its affine extension. The broken phase is then constructed by gauging a subgroup of the global symmetries. It is shown that metric, spin-2 fields and Kaluza-Klein vectors combine into a Chern-Simons theory for an extended algebra, in which the affine Poincaré subalgebra acquires a central extension.
Dynamics of localized Kaluza-Klein black holes in a collapsing universe
NASA Astrophysics Data System (ADS)
Kastor, David; Sorbo, Lorenzo; Traschen, Jennie
2012-03-01
The Clayton Antitrust Act of 1914 prohibits corporate mergers that would result in certain highly undesired end states. We study an exact solution of the Einstein equations describing localized, charged Kaluza-Klein black holes in a collapsing de Sitter universe and seek to demonstrate that a similar effect holds, preventing a potentially catastrophic black hole merger. As the collapse proceeds, it is natural to expect that the black hole undergoes a topological transition, wrapping around the shrinking compact dimension to merge with itself and form a black string. However, the putative uniform charged black string end state is singular and such a transition would violate (a reasonable notion of) cosmic censorship. We present analytic and numerical evidence that strongly suggests the absence of such a transition. Based on this evidence, we expect that the Kaluza-Klein black hole horizon stays localized, despite the increasingly constraining size of the compact dimension. On the other hand, the de Sitter horizon does change between spherical and cylindrical topologies in a simple way.
Kaluza-Klein graviton phenomenology for warped compactifications, and the 750 GeV diphoton excess
NASA Astrophysics Data System (ADS)
Giddings, Steven B.; Zhang, Hao
2016-06-01
A generic prediction of scenarios with extra dimensions accessible in TeV-scale collisions is the existence of Kaluza-Klein excitations of the graviton. For a broad class of strongly warped scenarios one expects to initially find an isolated resonance, whose phenomenology in the simplest cases is described by a simplified model with two parameters, its mass, and a constant Λ with units of mass parametrizing its coupling to the Standard Model stress tensor. These parameters are in turn determined by the geometrical configuration of the warped compactification. We explore the possibility that the 750 GeV excess recently seen in 13 TeV data at ATLAS and CMS could be such a warped Kaluza-Klein graviton, and find a best-fit value Λ ≈60 TeV . We find that while there is some tension between this interpretation and data from 8 TeV and from the dilepton channel at 13 TeV, it is not strongly excluded. However, in the simplest scenarios of this kind, such a signal should soon become apparent in both diphoton and dilepton channels.
Light Kaluza Klein States in Randall-Sundrum Models with Custodial SU(2)
Carena, Marcela; Ponton, Eduardo; Santiago, Jose; Wagner, Carlos E.M.; /Argonne /Chicago U., EFI /KICP, Chicago
2006-07-01
We consider Randall-Sundrum scenarios based on SU(2){sub L} x SU(2){sub R} and a discrete parity exchanging L with R. The custodial and parity symmetries can be used to make the tree level contribution to the T parameter and the anomalous couplings of the bottom quark to the Z very small. We show that the resulting quantum numbers typically induce a negative T parameter at one loop that, together with the positive value of the S parameter, restrict considerably these models. There are nevertheless regions of parameter space that successfully reproduce the fit to electroweak precision observables with light Kaluza-Klein excitations accessible at colliders. We consider models of gauge-Higgs unification that implement the custodial and parity symmetries and find that the electroweak data singles out a very well defined region in parameter space. In this region one typically finds light gauge boson Kaluza-Klein excitations as well as light SU(2){sub L} singlet, and sometimes also doublet, fermionic states, that mix with the top quark, and that may yield interesting signatures at future colliders.
Cross sections for production of closed superstrings at high energy colliders in brane world models
Chialva, Diego; Iengo, Roberto; Russo, Jorge G.
2005-05-15
In brane world string models with large extra dimensions, there are processes where fermion and antifermion (or two gluons) can annihilate producing a light particle (e.g. gluon) carrying transverse momentum and a Kaluza-Klein graviton or an excited closed string that propagates in the extra dimensions. In high energy colliders, this process gives a missing-momentum signature. We compute the total cross section for this process within the context of type II superstring theory in the presence of a D-brane. This includes all missing-energy sources for this string-theory model up to s=8M{sub s}{sup 2}, and it can be used to put new limits on the string scale M{sub s}.
Constraints on the size of the extra dimension from Kaluza-Klein gravitino decay
Gherson, David
2007-08-15
We study the consequences of the gravitino decay into dark matter. We suppose that the lightest neutralino is the main component of dark matter. In our framework the gravitino is heavy enough to decay before big bang nucleosynthesis starts. We consider a model coming from a five dimensional supergravity compactified on S{sup 1}/Z{sub 2} with gravity in the bulk and matter localized on tensionless branes at the orbifold fixed points. We require that the dark matter, which is produced thermally and in the decay of Kaluza-Klein modes of the gravitino, has an abundance compatible with observation. We deduce from our model that there are curves of constraints between the size of the extra dimension and the reheating temperature of the Universe after inflation.
Supersymmetric and Kaluza-Klein Particles Multiple Scattering in the Earth
Albuquerque, Ivone; Klein, Spencer
2009-05-19
Neutrino telescopes with cubic kilometer volume have the potential to discover new particles. Among them are next to lightest supersymmetric (NLSPs) and next to lightest Kaluza-Klein (NLKPs) particles. Two NLSPs or NLKPs will transverse the detector simultaneously producing parallel charged tracks. The track separation inside the detector can be a few hundred meters. As these particles might propagate a few thousand kilometers before reaching the detector, multiple scattering could enhance the pair separation at the detector. We find that the multiple scattering will alter the separation distribution enough to increase the number of NLKP pairs separated by more than 100 meters (a reasonable experimental cut) by up to 46% depending on the NLKP mass. Vertical upcoming NLSPs will have their separation increased by 24% due to multiple scattering.
Kaluza-Klein-Carmeli Metric from Quaternion-Clifford Space, Lorentz' Force, and Some Observables
NASA Astrophysics Data System (ADS)
Christianto, Vic; Smarandache, Florentin
2009-05-01
It was known for quite long time that a quaternion space can be generalized to a Clifford space, and vice versa; but how to find its neat link with more convenient metric form in the General Relativity theory, has not been explored extensively. We begin with a representation of group with non-zero quaternions to derive closed FLRW metric, and from there obtains Carmeli metric, which can be extended further to become 5D and 6D metric (which we propose to call Kaluza-Klein-Carmeli metric). Thereafter we discuss some plausible implications of this metric, beyond describing a galaxy's spiraling motion and redshift data as these have been done by Carmeli and Hartnett. In subsequent section we explain Podkletnov's rotating disc experiment. We also note possible implications to quantum gravity. Further observations are of course recommended in order to refute or verify this proposition.
Kaluza-Klein masses in nonprime orbifolds: Z{sub 12-I} compactification and threshold correction
Kim, Jihn E.; Kyae, Bumseok
2008-05-15
Analyzing the one-loop partition function, we discuss possible Kaluza-Klein (KK) states in the orbifold compactification of the heterotic string theory, toward the application to the threshold correction. The KK massive states associated with (relatively) large extra dimensions can arise only in nonprime orbifolds. The Gliozzi-Scherk-Olive (GSO) projection condition by a shift vector V{sup I} is somewhat relaxed above the compactification scale 1/R. We also present the other condition on Wilson line W, P{center_dot}W=integer. With the knowledge of the partition function, we obtain the threshold corrections to gauge couplings, which include the Wilson line effects. We point out the differences in string and field theoretic orbifolds.
Casimir Effect Near the Future Singularity in Kaluza Klein Viscous Cosmology
NASA Astrophysics Data System (ADS)
Khadekar, G. S.
2016-02-01
In this paper we investigate the analytical properties of the scalar expansion θ in the cosmic fluid close to the future singularity, when the fluid possesses a constant bulk viscosity ζ in the framework of Kaluza-Klein theory of gravitation. In addition, we assume the viscous cosmology theories in the sense that the Casimir contributions to the energy density and pressure are both proportional to 1/ a 4, where a being scale factor. We also worked out the series expansion for the scalar expansion θ under the condition that the Casimir influence is small. However, near to the big rip singularity the Casimir term has to fade away and we obtain the same singularity behavior for the scalar expansion θ, energy density ρ, the scale factor a as in the Casimir-free viscous case.
Zeta-function regularization approach to finite temperature effects in Kaluza-Klein space-times
Bytsenko, A.A. ); Vanzo, L.; Zerbini, S. )
1992-09-21
In the framework of heat-kernel approach to zeta-function regularization, in this paper the one-loop effective potential at finite temperature for scalar and spinor fields on Kaluza-Klein space-time of the form M[sup p] [times] M[sub c][sup n], where M[sup p] is p-dimensional Minkowski space-time is evaluated. In particular, when the compact manifold is M[sub c][sup n] = H[sup n]/[Gamma], the Selberg tracer formula associated with discrete torsion-free group [Gamma] of the n-dimensional Lobachevsky space H[sup n] is used. An explicit representation for the thermodynamic potential valid for arbitrary temperature is found. As a result a complete high temperature expansion is presented and the roles of zero modes and topological contributions is discussed.
A Note on Gaugino Masses in Kaluza-Klein/Radion Mediated SUSY Breaking
NASA Astrophysics Data System (ADS)
Agashe, Kaustubh
2001-05-01
We review the equivalence of two approaches to study theories with gauge fields in extra spatial dimensions, namely the ``4D'' approach (with KK states) and the ``5D'' approach (with matching to the 4D theory at the compactification scale). In particular, we reiterate that there are two different power-law scalings of ``effective'' gauge couplings. In a supersymmetric framework with SUSY breaking in the radius modulus, i.e. the field which fixes the size of the extra dimensions, these two approaches seem to give gaugino masses at loop-level (with a possible enhancement due to large number of Kaluza-Klein states) [1], and tree-level [2], respectively. We show explicitly how this discrepancy can be resolved.
NASA Astrophysics Data System (ADS)
Jain, Namrata I.; Bhoga, Shyamsunder S.
2015-08-01
Cosmological models with time varying gravitational constant G and cosmological constant Λ in the presence of viscous fluid in Kaluza-Klein metric were investigated. The solutions to Einstein Field Equation were obtained for different types of G, with bulk coefficient ξ = ξ 0 ρ d (where ρ is density of the Universe, d is some constant) and lambda Λ = α H 2 + β R -2 where H and R are Hubble parameter and scale factor respectively. Two possible models are suggested, one where G is proportional to H and, the other where G is inversely proportional to H. While the former leads to a non-singular model, the latter results in an inflationary model. Both Cosmological models show that the Universe is accelerating; but at the early stage of the Universe the behaviour of both models is quite different,which has been studied through the variation of decelerating parameter q with time.
Astrophysical Evidence for AN Extra Dimension: Phenomenology of a Kaluza-Klein Theory
NASA Astrophysics Data System (ADS)
Pugliese, D.; Montani, G.
2013-05-01
In this brief review, we discuss the viability of a multi-dimensional geometrical theory with one compactified dimension. We discuss the case of a Kaluza-Klein (KK) fifth-dimensional theory, addressing the problem by an overview of the astrophysical phenomenology associated with this five-dimensional (5D) theory. By comparing the predictions of our model with the features of the ordinary (four-dimensional (4D)) Relativistic Astrophysics, we highlight some small but finite discrepancies, expectably detectible from the observations. We consider a class of static, vacuum solutions of free electromagnetic KK equations with three-dimensional (3D) spherical symmetry. We explore the stability of the particle dynamics in these spacetimes, the construction of self-gravitating stellar models and the emission spectrum generated by a charged particle falling on this stellar object. The matter dynamics in these geometries has been treated by a multipole approach adapted to the geometric theory with a compactified dimension.
Gluon-initiated production of a Kaluza-Klein gluon in a bulk Randall-Sundrum model
NASA Astrophysics Data System (ADS)
Allanach, Benjamin C.; Mahmoudi, Farvah; Skittrall, Jordan P.; Sridhar, K.
2010-03-01
In the Bulk Randall-Sundrum model, the Kaluza-Klein excitations of the gauge bosons are the primary signatures. In particular, the search for the Kaluza-Klein (KK) excitation of the gluon at hadron colliders is of great importance in testing this model. At the leading order in QCD, the production of this KK-gluon proceeds only via qbar q -initial states. We study the production of KK-gluons from gluon initial states at next-to-leading order in QCD. We find that, even after including the sub-dominant KK-gluon loops at this order, the next-to-leading order (NLO) cross-section is tiny compared to the leading order cross-section and unlikely to impact the searches for this resonance at hardon colliders.
Yazadjiev, Stoytcho S.; Nedkova, Petia G.
2009-07-15
We present a general class of exact solutions in Einstein-Maxwell-dilaton gravity describing configurations of black holes and Kaluza-Klein bubbles magnetized along the compact dimension. Smarr-like relations for the mass and the tension are found. We also derive the mass and tension first laws for the configurations under consideration using the Noether current approach. The novelty is the appearance of new terms in the Smarr-like relations and the first laws containing the magnetic flux. The solutions we consider are also explicit examples showing that in Kaluza-Klein spacetimes the interval (rod) structure and the charges (which are zero by construction for the solutions here), are insufficient to classify the solutions and additional data is necessary, namely, the magnetic flux(es)
Kaluza-Klein cosmological model in f(R, T) gravity with Λ(T)
NASA Astrophysics Data System (ADS)
Sahoo, P. K.; Mishra, B.; Tripathy, S. K.
2016-04-01
A class of Kaluza-Klein cosmological models in $f(R,T)$ theory of gravity have been investigated. In the work, we have considered the functional $f(R,T)$ to be in the form $f(R,T)=f(R)+f(T)$ with $f(R)=\\lambda R$ and $f(T)=\\lambda T$. Such a choice of the functional $f(R,T)$ leads to an evolving effective cosmological constant $\\Lambda$ which depends on the stress energy tensor. The source of the matter field is taken to be a perfect cosmic fluid. The exact solutions of the field equations are obtained by considering a constant deceleration parameter which leads two different aspects of the volumetric expansion namely a power law and an exponential volumetric expansion. Keeping an eye on the accelerating nature of the universe in the present epoch, the dynamics and physical behaviour of the models have been discussed. From statefinder diagnostic pair we found that the model with exponential volumetric expansion behaves more like a $\\Lambda$CDM model.
Kaluza-Klein gluon + jets associated production at the Large Hadron Collider
NASA Astrophysics Data System (ADS)
Iyer, A. M.; Mahmoudi, F.; Manglani, N.; Sridhar, K.
2016-08-01
The Kaluza-Klein excitations of gluons offer the exciting possibility of probing bulk Randall-Sundrum (RS) models. In these bulk models either a custodial symmetry or a deformation of the metric away from AdS is invoked in order to deal with electroweak precision tests. Addressing both these models, we suggest a new channel in which to study the production of KK-gluons (gKK): one where it is produced in association with one or more hard jets. The cross-section for the gKK + jets channel is significant because of several contributing sub-processes. In particular, the 1-jet and the 2-jet associated processes are important because at these orders in QCD the qg and the gg initial states respectively come into play. We have performed a hadron-level simulation of the signal and present strategies to effectively extract the signal from what could potentially be a huge background. We present results for the kinematic reach of the LHC Run-II for different gKK masses in bulk-RS models.
Search for Kaluza-Klein gravitons in extra dimension models via forward detectors at the LHC
NASA Astrophysics Data System (ADS)
Cho, Gi-Chol; Kono, Takanori; Mawatari, Kentarou; Yamashita, Kimiko
2015-06-01
We investigate contributions of Kaluza-Klein (KK) graviton in extra dimension models to the process p p →p γ p →p γ j X , where a proton emits a quasireal photon and is detected by using the very forward detectors planned at the LHC. In addition to the γ q initial state as in the Compton scattering in the standard model, the γ g scattering contributes through the t -channel exchange of KK gravitons. Taking account of pileup contributions to the background and examining viable kinematical cuts, constraints on the parameter space of both the ADD (Arkani-Hamed, Dimopoulos and Dvali) model and the RS (Randall and Sundrum) model are studied. With 200 fb-1 data at a center-of-mass energy of 14 TeV, the expected lower bound on the cutoff scale for the ADD model is 6.3 TeV at 95% confidence level, while a lower limit of 2.0 (0.5) TeV is set on the mass of the first excited graviton with the coupling parameter k /M¯ Pl=0.1 (0.01 ) for the RS model.
The PAMELA and ATIC Signals From Kaluza-Klein Dark Matter
Hooper, Dan; Zurek, Kathryn M.; /Fermilab /Michigan U.
2009-02-01
In this letter, we study the possibility that Kaluza-Klein dark matter in a model with one universal extra dimension is responsible for the recent observations of the PAMELA and ATIC experiments. In this model, the dark matter particles annihilate largely to charged leptons, which enables them to produce a spectrum of cosmic ray electrons and positrons consistent with the PAMELA and ATIC measurements. To normalize to the observed signal, however, large boost factors ({approx}10{sup 3}) are required. Despite these large boost factors and significant annihilation to hadronic modes (35%), we find that the constraints from cosmic ray antiproton measurements can be satisfied. Relic abundance considerations in this model force us to consider a rather specific range of masses (approximately 600-900 GeV) which is very similar to the range required to generate the ATIC spectral feature. The results presented here can also be used as a benchmark for model-independent constraints on dark matter annihilation to hadronic modes.
Static wormholes on the brane inspired by Kaluza-Klein gravity
Leon, J. Ponce de
2009-11-01
We use static solutions of 5-dimensional Kaluza-Klein gravity to generate several classes of static, spherically symmetric spacetimes which are analytic solutions to the equation {sup (4)}R = 0, where {sup (4)}R is the four-dimensional Ricci scalar. In the Randall and Sundrum scenario they can be interpreted as vacuum solutions on the brane. The solutions contain the Schwarzschild black hole, and generate new families of traversable Lorenzian wormholes as well as nakedly singular spacetimes. They generalize a number of previously known solutions in the literature, e.g., the temporal and spatial Schwarzschild solutions of braneworld theory as well as the class of self-dual Lorenzian wormholes. A major departure of our solutions from Lorenzian wormholes a la Morris and Thorne is that, for certain values of the parameters of the solutions, they contain three spherical surfaces (instead of one) which are extremal and have finite area. Two of them have the same size, meet the ''flare-out'' requirements, and show the typical violation of the energy conditions that characterizes a wormhole throat. The other extremal sphere is ''flaring-in'' in the sense that its sectional area is a local maximum and the weak, null and dominant energy conditions are satisfied in its neighborhood. After bouncing back at this second surface a traveler crosses into another space which is the double of the one she/he started in. Another interesting feature is that the size of the throat can be less than the Schwarzschild radius 2M, which no longer defines the horizon, i.e., to a distant observer a particle or light falling down crosses the Schwarzschild radius in a finite time.
Hamiltonian Map to Conformal Modification of Spacetime Metric: Kaluza-Klein and TeVeS
NASA Astrophysics Data System (ADS)
Horwitz, Lawrence; Gershon, Avi; Schiffer, Marcelo
2011-01-01
It has been shown that the orbits of motion for a wide class of non-relativistic Hamiltonian systems can be described as geodesic flows on a manifold and an associated dual by means of a conformal map. This method can be applied to a four dimensional manifold of orbits in spacetime associated with a relativistic system. We show that a relativistic Hamiltonian which generates Einstein geodesics, with the addition of a world scalar field, can be put into correspondence in this way with another Hamiltonian with conformally modified metric. Such a construction could account for part of the requirements of Bekenstein for achieving the MOND theory of Milgrom in the post-Newtonian limit. The constraints on the MOND theory imposed by the galactic rotation curves, through this correspondence, would then imply constraints on the structure of the world scalar field. We then use the fact that a Hamiltonian with vector gauge fields results, through such a conformal map, in a Kaluza-Klein type theory, and indicate how the TeVeS structure of Bekenstein and Saunders can be put into this framework. We exhibit a class of infinitesimal gauge transformations on the gauge fields {mathcal{U}}_{μ}(x) which preserve the Bekenstein-Sanders condition {mathcal{U}}_{μ}{mathcal{U}}^{μ}=-1. The underlying quantum structure giving rise to these gauge fields is a Hilbert bundle, and the gauge transformations induce a non-commutative behavior to the fields, i.e. they become of Yang-Mills type. Working in the infinitesimal gauge neighborhood of the initial Abelian theory we show that in the Abelian limit the Yang-Mills field equations provide residual nonlinear terms which may avoid the caustic singularity found by Contaldi et al.
IceCube Collaboration; Abbasi, R.; al., et
2009-10-23
A search for muon neutrinos from Kaluza-Klein dark matter annihilations in the Sun has been performed with the 22-string configuration of the IceCube neutrino detector using data collected in 104.3 days of live-time in 2007. No excess over the expected atmospheric background has been observed. Upper limits have been obtained on the annihilation rate of captured lightest Kaluza-Klein particle (LKP) WIMPs in the Sun and converted to limits on the LKP-proton cross-sections for LKP masses in the range 250 - 3000 GeV. These results are the most stringent limits to date on LKP annihilation in the Sun.
‘Effective two dimensionality’ cases bring a new hope to the Kaluza-Klein(like) theories
NASA Astrophysics Data System (ADS)
Lukman, D.; Mankoč Borštnik, N. S.; Nielsen, H. B.
2011-10-01
One step towards realistic Kaluza-Klein(like) theories and a loophole through Witten's ‘no-go theorem’ is presented for cases that we call effective two dimensionality cases: in d = 2, the equations of motion following from the action with the linear curvature leave spin connections and zweibeins undetermined. We present the case of a spinor in d = (1 + 5) compactified on a formally infinite disc with the zweibein that makes a disc curved on an almost S2 and with the spin connection field that allows on such a sphere only one massless normalizable spinor state of a particular charge, which couples the spinor chirally to the corresponding Kaluza-Klein gauge field. We assume no external gauge fields. The masslessness of a spinor is achieved by the choice of a spin connection field (which breaks the left-right symmetry), the zweibein and the normalizability condition for spinor states, which guarantee a discrete spectrum forming the complete basis. We discuss the meaning of the hole, which manifests the non-compactness of the space.
String inspired brane world cosmology.
Germani, Cristiano; Sopuerta, Carlos F
2002-06-10
We consider brane world scenarios including the leading correction to the Einstein-Hilbert action suggested by superstring theory, the Gauss-Bonnet term. We obtain and study the complete set of equations governing the cosmological dynamics. We find they have the same form as those in Randall-Sundrum scenarios but with time-varying four-dimensional gravitational and cosmological constants. By studying the bulk geometry we show that this variation is produced by bulk curvature terms parametrized by the mass of a black hole. Finally, we show there is a coupling between these curvature terms and matter that can be relevant for early universe cosmology. PMID:12059347
Uniqueness theorem for black holes with Kaluza-Klein asymptotic in 5D Einstein-Maxwell gravity
Yazadjiev, Stoytcho
2010-07-15
In the present paper, we prove a uniqueness theorem for stationary multi-black hole configurations with Kaluza-Klein asymptotic in a certain sector of 5D Einstein-Maxwell gravity. As a part of the technical assumptions in the theorem, we assume that the Killing vector associated with the compact dimension is orthogonal to the other Killing vectors and that it is also hypersurface orthogonal. About the Maxwell field, we assume that it is invariant under the Killing symmetries and has a nonzero component only along the Killing vector associated with the compact dimension. We show that such multi-black hole configurations are uniquely specified by the interval structure, angular momenta of the horizons, magnetic charges, and the magnetic flux. A straightforward generalization of the uniqueness theorem for 5D Einstein-Maxwell-dilaton gravity is also given.
Acosta, D; Affolder, T; Akimoto, H; Albrow, M G; Ambrose, D; Amidei, D; Anikeev, K; Antos, J; Apollinari, G; Arisawa, T; Artikov, A; Asakawa, T; Ashmanskas, W; Azfar, F; Azzi-Bacchetta, P; Bacchetta, N; Bachacou, H; Badgett, W; Bailey, S; de Barbaro, P; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Barone, M; Bauer, G; Bedeschi, F; Behari, S; Belforte, S; Bell, W H; Bellettini, G; Bellinger, J; Benjamin, D; Bensinger, J; Beretvas, A; Berryhill, J; Bhatti, A; Binkley, M; Bisello, D; Bishai, M; Blair, R E; Blocker, C; Bloom, K; Blumenfeld, B; Blusk, S R; Bocci, A; Bodek, A; Bolla, G; Bolshov, A; Bonushkin, Y; Bortoletto, D; Boudreau, J; Brandl, A; Bromberg, C; Brozovic, M; Brubaker, E; Bruner, N; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Byrum, K L; Cabrera, S; Calafiura, P; Campbell, M; Carithers, W; Carlson, J; Carlsmith, D; Caskey, W; Castro, A; Cauz, D; Cerri, A; Cerrito, L; Chan, A W; Chang, P S; Chang, P T; Chapman, J; Chen, C; Chen, Y C; Cheng, M-T; Chertok, M; Chiarelli, G; Chirikov-Zorin, I; Chlachidze, G; Chlebana, F; Christofek, L; Chu, M L; Chung, J Y; Chung, W-H; Chung, Y S; Ciobanu, C I; Clark, A G; Coca, M; Connolly, A; Convery, M; Conway, J; Cordelli, M; Cranshaw, J; Culbertson, R; Dagenhart, D; D'Auria, S; De Cecco, S; DeJongh, F; Dell'Agnello, S; Dell'Orso, M; Demers, S; Demortier, L; Deninno, M; De Pedis, D; Derwent, P F; Devlin, T; Dionisi, C; Dittmann, J R; Dominguez, A; Donati, S; D'Onofrio, M; Dorigo, T; Eddy, N; Einsweiler, K; Engels, E; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fan, Q; Farrington, S; Feild, R G; Fernandez, J P; Ferretti, C; Field, R D; Fiori, I; Flaugher, B; Flores-Castillo, L R; Foster, G W; Franklin, M; Freeman, J; Friedman, J; Fukui, Y; Furic, I; Galeotti, S; Gallas, A; Gallinaro, M; Gao, T; Garcia-Sciveres, M; Garfinkel, A F; Gatti, P; Gay, C; Gerdes, D W; Gerstein, E; Giagu, S; Giannetti, P; Giolo, K; Giordani, M; Giromini, P; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Goldstein, J; Gomez, G; Goncharov, M; Gorelov, I; Goshaw, A T; Gotra, Y; Goulianos, K; Green, C; Gresele, A; Grim, G; Grosso-Pilcher, C; Guenther, M; Guillian, G; Guimaraes da Costa, J; Haas, R M; Haber, C; Hahn, S R; Halkiadakis, E; Hall, C; Handa, T; Handler, R; Happacher, F; Hara, K; Hardman, A D; Harris, R M; Hartmann, F; Hatakeyama, K; Hauser, J; Heinrich, J; Heiss, A; Hennecke, M; Herndon, M; Hill, C; Hocker, A; Hoffman, K D; Hollebeek, R; Holloway, L; Hou, S; Huffman, B T; Hughes, R; Huston, J; Huth, J; Ikeda, H; Issever, C; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iwai, J; Iwata, Y; Iyutin, B; James, E; Jones, M; Joshi, U; Kambara, H; Kamon, T; Kaneko, T; Kang, J; Karagoz Unel, M; Karr, K; Kartal, S; Kasha, H; Kato, Y; Keaffaber, T A; Kelley, K; Kelly, M; Kennedy, R D; Kephart, R; Khazins, D; Kikuchi, T; Kilminster, B; Kim, B J; Kim, D H; Kim, H S; Kim, M J; Kim, S B; Kim, S H; Kim, T H; Kim, Y K; Kirby, M; Kirk, M; Kirsch, L; Klimenko, S; Koehn, P; Kondo, K; Konigsberg, J; Korn, A; Korytov, A; Kotelnikov, K; Kovacs, E; Kroll, J; Kruse, M; Krutelyov, V; Kuhlmann, S E; Kurino, K; Kuwabara, T; Kuznetsova, N; Laasanen, A T; Lai, N; Lami, S; Lammel, S; Lancaster, J; Lannon, K; Lancaster, M; Lander, R; Lath, A; Latino, G; LeCompte, T; Le, Y; Lee, J; Lee, S W; Leonardo, N; Leone, S; Lewis, J D; Li, K; Lin, C S; Lindgren, M; Liss, T M; Liu, J B; Liu, T; Liu, Y C; Litvintsev, D O; Lobban, O; Lockyer, N S; Loginov, A; Loken, J; Loreti, M; Lucchesi, D; Lukens, P; Lusin, S; Lyons, L; Lys, J; Madrak, R; Maeshima, K; Maksimovic, P; Malferrari, L; Mangano, M; Manca, G; Mariotti, M; Martignon, G; Martin, M; Martin, A; Martin, V; Martínez, M; Matthews, J A J; Mazzanti, P; McFarland, K S; McIntyre, P; Menguzzato, M; Menzione, A; Merkel, P; Mesropian, C; Meyer, A; Miao, T; Miller, R; Miller, J S; Minato, H; Miscetti, S; Mishina, M; Mitselmakher, G; Miyazaki, Y; Moggi, N; Moore, E; Moore, R; Morita, Y; Moulik, T; Mulhearn, M; Mukherjee, A; Muller, T; Munar, A; Murat, P; Murgia, S; Nachtman, J; Nagaslaev, V; Nahn, S; Nakada, H; Nakano, I; Napora, R; Niell, F; Nelson, C; Nelson, T; Neu, C; Neubauer, M S; Neuberger, D; Newman-Holmes, C; Ngan, C-Y P; Nigmanov, T; Niu, H; Nodulman, L; Nomerotski, A; Oh, S H; Oh, Y D; Ohmoto, T; Ohsugi, T; Oishi, R; Okusawa, T; Olsen, J; Orejudos, W; Pagliarone, C; Palmonari, F; Paoletti, R; Papadimitriou, V; Partos, D; Patrick, J; Pauletta, G; Paulini, M; Pauly, T; Paus, C; Pellett, D; Penzo, A; Pescara, L; Phillips, T J; Piacentino, G; Piedra, J; Pitts, K T; Pompos, A; Pondrom, L; Pope, G; Pratt, T; Prokoshin, F; Proudfoot, J; Ptohos, F; Pukhov, O; Punzi, G; Rademacker, J; Rakitine, A; Ratnikov, F; Ray, H; Reher, D; Reichold, A; Renton, P; Rescigno, M; Ribon, A; Riegler, W; Rimondi, F; Ristori, L; Riveline, M; Robertson, W J; Rodrigo, T; Rolli, S; Rosenson, L; Roser, R; Rossin, R; Rott, C; Roy, A; Ruiz, A; Ryan, D; Safonov, A; St Denis, R
2004-03-26
We report on a search for direct Kaluza-Klein graviton production in a data sample of 84 pb(-1) of ppmacr; collisions at sqrt[s]=1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and one or two high energy jets. We compare the data with the predictions from a (3+1+n)-dimensional Kaluza-Klein scenario in which gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for n=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71 TeV, respectively. PMID:15089665
An Expanding 4d Universe in a 5d Kaluza-Klein Cosmology with Higher Dimensional Matter
NASA Astrophysics Data System (ADS)
Darabi, F.
In the framework of Kaluza-Klein theory, we investigate a (4+1)-dimensional universe consisting of a (4+1)-dimensional Robertson-Walker type metric coupled with a (4+1)-dimensional energy-momentum tensor. The matter part consists of an energy density together with a pressure subject to 4D part of the (4+1)-dimensional energy-momentum tensor. The dark part consists of just a dark pressure bar {p}, corresponding to the extra-dimension endowed by a scalar field, with no element of dark energy. It is shown that the reduced Einstein field equations are free of 4D pressure and are just affected by an effective pressure produced by the 4D energy density and dark pressure. It is then proposed that the expansion of the universe may be controlled by the equation of state in higher dimension rather than four dimensions. This may account for the current acceleration at the beginning or in the middle of matter dominant era.
NASA Astrophysics Data System (ADS)
Ebert, Dietmar; Plefka, Jan; Rodigast, Andreas
2009-02-01
We study the question of a modification of the running gauge coupling of Yang-Mills theories due to quantum gravitational effects in a compact large extra dimensional brane world scenario with a low energy quantum gravity scale. The ADD scenario is applied for a D = d+δ dimensional space-time in which gravitons freely propagate, whereas the non-abelian gauge fields are confined to a d-dimensional brane. The extra dimensions are taken to be toroidal and the transverse fluctuation modes (branons) of the brane are taken into account. On this basis we have calculated the one-loop corrections due to virtual Kaluza-Klein graviton and branon modes for the gluon two- and three-point functions in an effective field theory treatment. Applying momentum cut-off regularization we find that for a d = 4 brane the leading gravitational divergencies cancel irrespective of the number of extra dimensions δ, generalizing previous results in the absence of extra-dimensions. Hence, again the Yang-Mills β-function receives no gravitational corrections at one-loop. This is no longer true in a `universal' extra dimensional scenario with a d > 4 dimensional brane. Moreover, the subleading power-law gravitational divergencies induce higher-dimensional counterterms, which we establish in our scheme. Interestingly, for d = 4 these gravitationally induced counterterms are of the form recently considered in non-abelian Lee-Wick extensions of the standard model—now with a possible mass scale in the TeV range due to the presence of large extra dimensions.
NASA Astrophysics Data System (ADS)
Smolyakov, Mikhail N.; Volobuev, Igor P.
2016-01-01
In this paper we examine, from the purely theoretical point of view and in a model-independent way, the case, when matter, gauge and Higgs fields are allowed to propagate in the bulk of five-dimensional brane world models with compact extra dimension, and the Standard Model fields and their interactions are supposed to be reproduced by the corresponding zero Kaluza-Klein modes. An unexpected result is that in order to avoid possible pathological behavior in the fermion sector, it is necessary to impose constraints on the fermion field Lagrangian. In the case when the fermion zero modes are supposed to be localized at one of the branes, these constraints imply an additional relation between the vacuum profile of the Higgs field and the form of the background metric. Moreover, this relation between the vacuum profile of the Higgs field and the form of the background metric results in the exact reproduction of the gauge boson and fermion sectors of the Standard Model by the corresponding zero mode four-dimensional effective theory in all the physically relevant cases, allowed by the absence of pathologies. Meanwhile, deviations from these conditions can lead either back to pathological behavior in the fermion sector or to a variance between the resulting zero mode four-dimensional effective theory and the Standard Model, which, depending on the model at hand, may, in principle, result in constraints putting the theory out of the reach of the present day experiments.
Energy scales in a stabilized brane world
Boos, Edward E.; Mikhailov, Yuri S.; Smolyakov, Mikhail N.; Volobuev, Igor P.; /SINP, Moscow
2004-12-01
Brane world gravity looks different for observers on positive and negative tension branes. First we consider the well-known RS1 model with two branes embedded into the AdS5 space-time and recall the results on the relations between the energy scales for an observer on the negative tension brane, which is supposed to be ''our'' brane. Then from the point of view of this observer we study energy scales and masses for the radion and graviton excitations in a stabilized brane world model. We argue that there may be several possibilities leading to scales of the order 1-10 TeV or even less for new physics effects on our brane. In particular, an interesting scenario can arise in the case of a ''symmetric'' brane world with a nontrivial warp factor in the bulk, which however takes equal values on both branes.
de Sitter and double asymmetric brane worlds
Guerrero, Rommel; Rodriguez, R. Omar; Torrealba, Rafael
2005-12-15
Asymmetric brane worlds with dS expansion and static double kink topology are obtained from a recently proposed method and their properties are analyzed. These domain walls interpolate between two spacetimes with different cosmological constants. In the dynamic case, the vacua correspond to dS and AdS geometry, unlike the static case where they correspond to AdS background. We show that it is possible to confine gravity on such branes. In particular, the double-brane world hosts two different walls, so that the gravity is localized on one of them.
Savina, M. V.
2015-06-15
A survey of the results of the Compact Muon Solenoid (CMS) experiment that concern searches for massive Kaluza-Klein graviton excitations and microscopic black holes, quantum black holes, and string balls within models of low-energy multidimensional gravity is presented on behalf of the CMS Collaboration. The analysis in question is performed on the basis of a complete sample of data accumulated for proton-proton collisions at the c.m. energies of 7 and 8 TeV at the Large Hadron Collider (LHC) over the period spanning 2010 and 2012.
Hamiltonian Formulation of the 5-D Kaluza-Klein Model and Test-Particle Motion
NASA Astrophysics Data System (ADS)
Lacquaniti, Valentino; Montani, Giovanni
2008-09-01
We examine the ADM reformulation of the 5-D KK model: the dimensional reduction is provided to commute with the ADM splitting and we show how the time component of the gauge vector is given by combination of the Lagrangian multipliers for the 5-D gravitational field. We consider 5D particles motion and after dimensional reduction the definition of charge is recovered within electrodynamic coupling. A time-varying fine structure constant is recognized because an extra scalar field is present in the 4-D theory.
Davis, Stephen C.; Brechet, Sylvain
2005-05-15
The bubble nucleation rate for a first order phase transition occurring on a brane world is calculated. Both the Coleman-de Luccia thin wall instanton and the Hawking-Moss instanton are considered. The results are compared with the corresponding nucleation rates for standard four-dimensional gravity.
Gauge invariance, quantization and integration of heavy modes in a gauge Kaluza-Klein theory
NASA Astrophysics Data System (ADS)
Novales-Sánchez, H.
This dissertation examines topics at the intersection of environmental and energy economics. The first two chapters explore how policies can induce more efficient use of the energy sources available for generating electricity. The electricity sector is a major source of a wide variety of harmful pollutants. To mitigate the environmental impacts of electricity production, a variety of policies are being implemented to increase the quantity of generation from clean, renewable energy sources. The first chapter identifies the short-run reductions in emissions caused by generation from a particular renewable technology; wind turbines. Using the estimates of the pollution offset by the renewable production, I explore the efficiency of the incentives created by the current set of renewable energy policies. The second chapter examines the impact adding bulk electricity storage capacity will have on the full social costs of generating electricity. The third chapter explores the impact of various gasoline tax structures on both retail price volatility and state revenue volatility.
Akhoury, Ratindranath; Gauthier, Christopher S.
2008-11-15
We investigate decoupling of heavy Kaluza-Klein (KK) modes in an Abelian Higgs model with space-time topologies R{sup 3,1}xS{sup 1} and R{sup 3,1}xS{sup 1}/Z{sub 2}. After integrating out only the heavy KK modes we find the one-loop, light-particle (irreducible) effective action (LPEA) for the zero-mode fields. We find that in the R{sup 3,1}xS{sup 1} topology the heavy modes do not decouple in this low-energy effective action, due to the zero mode of the 5th component of the 5D gauge field A{sub 5}. Because A{sub 5} is a scalar under 4D Lorentz transformations, there is no gauge symmetry protecting it from getting mass and A{sub 5}{sup 4} interaction terms after loop corrections. In addition, after symmetry breaking, we find that the effective action has new divergences in the A{sub 5} mass that did not appear in the symmetric phase. The new divergences are traced back to the gauge-goldstone mixing that occurs after symmetry breaking. We find that when considering low-energy physical processes, however, the divergences of the zero-mode loop diagrams will cancel the divergences in the effective action, rendering the radiatively corrected couplings finite. Although, this clears up the extra divergences in the A{sub 5} sector, the gauge coupling still has a different compactification scale dependence in the A{sub 5} then it does in the A{sub {mu}} sector, leading to an explicit violation of decoupling. If instead of the LPEA one considers the Wilsonian effective action by integrating out zero modes of momenta |p|>M (M is the mass of the lowest KK excitation) in addition to the heavy modes, then decoupling is manifest. However, as is well known the price is the difficulty in maintaining 4D Lorentz and gauge invariance. In order to get a more sensible effective theory in the LPEA formalism, we investigate the S{sup 1}/Z{sub 2} compactification. With this kind of compact topology, the A{sub 5} zero mode disappears. With no A{sub 5}, there are no new divergences and the
Electromagnetic perturbations in new brane world scenarios
NASA Astrophysics Data System (ADS)
Molina, C.; Pavan, A. B.; Medina Torrejón, T. E.
2016-06-01
In this work, we consider electromagnetic dynamics in Randall-Sundrum branes. It is derived from a family of four-dimensional spacetimes compatible with Randall-Sundrum brane worlds, focusing on asymptotic flat backgrounds. Maximal extensions of the solutions are constructed, and their causal structures are discussed. These spacetimes include singular, nonsingular, and extreme black holes. Maxwell's electromagnetic field is introduced, and its evolution is studied in an extensive numerical survey. Electromagnetic quasinormal mode spectra are derived and analyzed with time-dependent and high-order WKB methods. Our results indicate that the black holes in the brane are electromagnetically stable.
Asymptotically Lifshitz brane-world black holes
Ranjbar, Arash Sepangi, Hamid Reza Shahidi, Shahab
2012-12-15
We study the gravity dual of a Lifshitz field theory in the context of a RSII brane-world scenario, taking into account the effects of the extra dimension through the contribution of the electric part of the Weyl tensor. We study the thermodynamical behavior of such asymptotically Lifshitz black holes. It is shown that the entropy imposes the critical exponent z to be bounded from above. This maximum value of z corresponds to a positive infinite entropy as long as the temperature is kept positive. The stability and phase transition for different spatial topologies are also discussed. - Highlights: Black-Right-Pointing-Pointer Studying the gravity dual of a Lifshitz field theory in the context of brane-world scenario. Black-Right-Pointing-Pointer Studying the thermodynamical behavior of asymptotically Lifshitz black holes. Black-Right-Pointing-Pointer Showing that the entropy imposes the critical exponent z to be bounded from above. Black-Right-Pointing-Pointer Discussing the phase transition for different spatial topologies.
Gravity on codimension 2 brane worlds
Navarro, Ignacio; Santiago, Jose; /Durham U., IPPP /Fermilab
2004-11-01
The authors compute the matching conditions for a general thick codimension 2 brane, a necessary previous step towards the investigation of gravitational phenomena in co-dimension 2 braneworlds. They show that, provided the brane is weakly curved, they are specified by the integral in the extra dimensions of the brane energy-momentum, independently of its detailed internal structure. These general matching conditions can then be used as boundary conditions for the bulk solution. By evaluating Einstein equations at the brane boundary they are able to write an evolution equation for the induced metric on the brane depending only on physical brane parameters and the bulk energy-momentum tensor. They particularize to a cosmological metric and show that a realistic cosmology can be obtained in the simplest case of having just a non-zero cosmological constant in the bulk. They point out several parallelisms between this case and the codimension 1 brane worlds in an AdS space.
Clustering of galaxies in brane world models
NASA Astrophysics Data System (ADS)
Hameeda, Mir; Faizal, Mir; Ali, Ahmed Farag
2016-04-01
In this paper, we analyze the clustering of galaxies using a modified Newtonian potential. This modification of the Newtonian potential occurs due to the existence of extra dimensions in brane world models. We will analyze a system of galaxies interacting with each other through this modified Newtonian potential. The partition function for this system of galaxies will be calculated, and this partition function will be used to calculate the free energy of this system of galaxies. The entropy and the chemical potential for this system will also be calculated. We will derive explicit expression for the clustering parameter for this system. This parameter will determine the behavior of this system, and we will be able to express various thermodynamic quantities using this clustering parameter. Thus, we will be able to explicitly analyze the effect that modifying the Newtonian potential can have on the clustering of galaxies. We also analyse the effect of extra dimensions on the two-point functions between galaxies.
NASA Astrophysics Data System (ADS)
Pasqua, Antonio; Chattopadhyay, Surajit; Assaf, Khudhair A.; Salako, Ines G.
2016-06-01
In this paper, we study the properties of the Holographic Dark Energy (HDE) model in the context of Kaluza-Klein (KK) cosmology with infrared cut-off given by the recently proposed by Granda-Oliveros cut-off, which contains a term proportional to the time derivative of the Hubble parameter and one proportional to the Hubble parameter squared. Moreover, this cut-off is characterized by two free parameters which are the proportional constants of the two terms of the cut-off. We derive the expression of the Equation of State (EoS) parameter ωD and of the deceleration parameter q for both non-interacting and interacting Dark Sectors and in the limiting case of a flat Dark Dominated Universe. Moreover, we study the squared speed of the sound vs2 and the statefinder diagnostic \\{r,s\\} in order to understand the cosmological properties of the model considered. We also develop a correspondence between the model considered and three scalar field models: the tachyon, the k-essence and the quintessence ones.
Photo-production of a 750 GeV di-photon resonance mediated by Kaluza-Klein leptons in the loop
NASA Astrophysics Data System (ADS)
Abel, Steven; Khoze, Valentin V.
2016-05-01
We consider the phenomenology of a 750 GeV resonance X which can be produced at the LHC by only photon fusion and subsequently decay into di-photons. We propose that the spin-zero state X is coupled to a heavy lepton that lives in the bulk of a higher-dimensional theory and interacts only with the photons of the Standard Model. We compute the di-photon rate in these models with two and more compact extra dimensions and demonstrate that they allow for a compelling explanation of the di-photon excess recently observed by the ATLAS and CMS collaborations. The central role in our approach is played by the summation over the Kaluza-Klein modes of the new leptons, thus providing a significant enhancement of the X → γγ loops for the production and decay subprocesses. It is expected that the jet activity accompanying these purely electromagnetic (at the partonic level) processes is numerically suppressed by factors such as {α}_{em}^2{{C}}_{qoverline{q}}/{{C}}_{γ γ}˜ 1{0}^{-3}.
Simple brane-world inflationary models — An update
NASA Astrophysics Data System (ADS)
Okada, Nobuchika; Okada, Satomi
2016-05-01
In the light of the Planck 2015 results, we update simple inflationary models based on the quadratic, quartic, Higgs and Coleman-Weinberg potentials in the context of the Randall-Sundrum brane-world cosmology. Brane-world cosmological effect alters the inflationary predictions of the spectral index (ns) and the tensor-to-scalar ratio (r) from those obtained in the standard cosmology. In particular, the tensor-to-scalar ratio is enhanced in the presence of the 5th dimension. In order to maintain the consistency with the Planck 2015 results for the inflationary predictions in the standard cosmology, we find a lower bound on the five-dimensional Planck mass (M5). On the other hand, the inflationary predictions laying outside of the Planck allowed region can be pushed into the allowed region by the brane-world cosmological effect with a suitable choice of M5.
Effective theory of brane world with small tension
NASA Astrophysics Data System (ADS)
Hisano, Junji; Okada, Nobuchika
2000-05-01
The five dimensional theory compactified on S1 with two ``branes'' (two domain walls) embedded in it is constructed, based on the field-theoretic mechanism to generate the ``brane.'' Some light states localized in the ``brane'' appear in the theory. One is the Nambu-Goldstone boson, which corresponds to the breaking of the translational invariance in the transverse direction of the ``brane.'' In addition, if the tension of the ``brane'' is smaller than the fundamental scale of the original theory, it is found that there may exist not only massless states but also some massive states lighter than the fundamental scale in the ``brane.'' We analyze the four dimensional effective theory by integrating out the freedom of the fifth dimension. We show that some effective couplings can be explicitly calculated. As one of our results, some effective couplings of the state localized in the ``brane'' to the higher Kaluza-Klein modes in the bulk are found to be suppressed by the width of the ``brane.'' The resultant suppression factor can be quantitatively different from the one analyzed by Bando et al. using the Nambu-Goto action, while they are qualitatively the same.
Note on regular black holes in a brane world
NASA Astrophysics Data System (ADS)
Neves, J. C. S.
2015-10-01
In this work, we show that regular black holes in a Randall-Sundrum-type brane world model are generated by the nonlocal bulk influence, expressed by a constant parameter in the brane metric, only in the spherical case. In the axial case (black holes with rotation), this influence forbids them. A nonconstant bulk influence is necessary to generate regular black holes with rotation in this context.
Classical and quantum aspects of brane-world cosmology
Cordero, Ruben; Rojas, Efrain
2011-10-14
We give a brief overview of several models in brane-world cosmology. In particular, we focus on the asymmetric DGP and Regge-Teiltelboim models. We present the associated equations of motion governing the dynamics of the brane and their corresponding Friedmann-like equations. In order to develop the quantum Regge-Teiltelboim type cosmology we construct its Ostrogradski Hamiltonian formalism which naturally leads to the corresponding Wheeler-DeWitt equation. In addition, we comment on possible generalizations for these models including second order derivative geometrical terms.
Brane world generated dynamically from string type IIB matrices
Nishimura; Vernizzi
2000-11-27
We have recently proposed a dynamical mechanism that may realize a flat four-dimensional space-time as a brane in type IIB superstring theory. A crucial role is played by the phase of the chiral fermion integral associated with the IKKT (Ishibashi-Kawai-Kitazawa-Tsuchiya) matrix theory, which is conjectured to be a nonperturbative definition of type IIB superstring theory. We demonstrate our mechanism by studying a simplified model, in which we find that a lower-dimensional brane indeed appears dynamically. We also comment on some implications of our mechanism on model building of the brane world. PMID:11082622
Gauss-Bonnet Brane World Gravity with a Scalar Field
Davis, Stephen C.
2004-11-17
The effective four-dimensional, linearised gravity of a brane world model with one extra dimension and a single brane is analysed. The model includes higher order curvature terms (such as the Gauss-Bonnet term) and a conformally coupled scalar field. Large and small distance gravitational laws are derived. In contrast to the corresponding Einstein gravity models, it is possible to obtain solutions with localised gravity which are compatible with observations. Solutions with non-standard large distance Newtonian potentials are also described.
The Einstein equations on the 3-brane world
NASA Astrophysics Data System (ADS)
Shiromizu, Tetsuya; Maeda, Kei-Ichi; Sasaki, Misao
2000-07-01
We carefully investigate the gravitational equations of the brane world, in which all the matter forces except gravity are confined on the 3-brane in a 5-dimensional spacetime with Z2 symmetry. We derive the effective gravitational equations on the brane, which reduce to the conventional Einstein equations in the low energy limit. From our general argument we conclude that the first Randall-Sundrum-type theory predicts that the brane with a negative tension is an antigravity world and hence should be excluded from the physical point of view. Their second-type theory where the brane has a positive tension provides the correct signature of gravity. In this latter case, if the bulk spacetime is exactly anti-de Sitter spacetime, generically the matter on the brane is required to be spatially homogeneous because of the Bianchi identities. By allowing deviations from anti-de Sitter spacetime in the bulk, the situation will be relaxed and the Bianchi identities give just the relation between the Weyl tensor and the energy momentum tensor. In the present brane world scenario, the effective Einstein equations cease to be valid during an era when the cosmological constant on the brane is not well defined, such as in the case of the matter dominated by the potential energy of the scalar field.
Holographic cosmic quintessence on the dilatonic brane world
NASA Astrophysics Data System (ADS)
Chen, Bin; Lin, Feng-Li
2002-02-01
Recently quintessence has been proposed to explain the observation data of supernovae indicating a time-varying cosmological constant and accelerating universe. Inspired by this and its mysterious origin, we look for the possibility that quintessence is the holographic dark matter dominating in the late time in the brane world scenarios. We consider both the cases of a static and moving brane in a dilaton gravity background. For the static brane we use the Hamilton-Jacobi method motivated by holographic renormalization group to study the intrinsic FRW cosmology on the brane and find the constraint on the bulk potential for quintessence. This constraint requires a negative slowly varying bulk potential which implies an anti-de Sitter-like bulk geometry and could be possibly realized from higher dimensional supergravities or string theory. We find a similar constraint for the moving brane cases and that the quintessence on it has the effect of a mildly time-varying Newton constant.
The fate of Newton's law in brane-world scenarios
NASA Astrophysics Data System (ADS)
Benichou, Raphael; Estes, John
2012-06-01
We consider brane-world scenarios embedded into string theory. We find that the D-brane backreaction induces a large increase in the open string's proper length. Consequently the stringy nature of elementary particles can be detected at distances much larger than the fundamental string scale. As an example, we compute the gravitational potential between two open strings ending on backreacting D3-branes in four-dimensional compactifications of type II string theory. We find that the Newtonian potential receives a correction that goes like 1 / r but that is not proportional to the inertial masses of the open strings, implying a violation of the equivalence principle in the effective gravitational theory. This stringy correction is screened by thermal effects when the distance between the strings is greater than the inverse temperature. This suggests new experimental tests for many phenomenological models in type II string theory.
Semisimple group unification in the supersymmetric brane world
NASA Astrophysics Data System (ADS)
Imamura, Y.; Watari, T.; Yanagida, T.
2001-09-01
The conventional supersymmetric grand unified theories suffer from two serious problems: the large mass splitting between doublet and triplet Higgs multiplets, and the too long lifetime of the proton. A unification model based on a semisimple group SU(5)GUT×U(3)H has been proposed to solve both of the problems simultaneously. Although the proposed model is perfectly consistent with observations, there are various mysteries. In this paper we show that such mysterious features in the original model are naturally explained by embedding the model into the brane world in a higher-dimensional space-time. In particular, the relatively small gauge coupling constant of the SU(5)GUT at the unification energy scale is a consequence of a relatively large volume of extra dimensions. Here, we put the SU(5)GUT gauge multiplet in a six-dimensional bulk and assume all fields in the U(3)H sector to reside on a three-dimensional brane located in the bulk. On the other hand, all chiral multiplets of quarks, leptons, and Higgs bosons are assumed to reside on a 3-brane at a T2/Z4 orbifold fixed point. The quasi-N=2 supersymmetry in the hypercolor U(3)H sector is understood as a low-energy remnant of the N=4 supersymmetry in a six-dimensional space-time. We further extend the six-dimensional model to a ten-dimensional theory. Possible frameworks of string theories are also investigated to accommodate the present brane-world model. We find that the type-IIB string theory with a D3-D7 brane structure is an interesting candidate.
Topics in brane world and quantum field theory
NASA Astrophysics Data System (ADS)
Corradini, Olindo
In the first part of the thesis we study various issues in the Brane World scenario with particular emphasis on gravity and the cosmological constant problem. First, we study localization of gravity on smooth domain-wall solutions of gravity coupled to a scalar field. In this context we discuss how the aforementioned localization is affected by including higher curvature terms in the theory, pointing out among other things that, general combinations of such terms lead to delocalization of gravity with the only exception of the Gauss-Bonnet combination (and its higher dimensional counterparts). We then find a solitonic 3-brane solution in 6D bulk in the Einstein-Hilbert-Gauss-Bonnet theory of gravity. Near to the brane the metric is that for a product of the 4D flat Minkowski space with a 2D wedge whose deficit angle is proportional to the brane tension. Consistency tests imposed on such backgrounds appear to require the localized matter on the brane to be conformal. We then move onto infinite volume extra dimension Brane World scenarios where we study gravity in a codimension-2 model, generalizing the work of Dvali, Gabadadze and Porrati to tensionful branes. We point out that, in the presence of the bulk Gauss-Bonnet combination, the Einstein-Hilbert term is induced on the brane already at the classical level. Consistency tests are presented here as well. To conclude we discuss, using String Theory, an interesting class of large-N gauge theories which have vanishing energy density even though these theories are non-covariant and non-supersymmetric. In the second part of the thesis we study a formulation of Quantum Mechanical Path Integrals in curved space. Such Path Integrals present superficial divergences which need to be regulated. We perform a three-loop calculation in mode regularization as a nontrivial check of the non-covariant counterterms required by such scheme. We discover that dimensional regularization can be successfully adopted to evaluate the
Simple inflationary models in Gauss–Bonnet brane-world cosmology
NASA Astrophysics Data System (ADS)
Okada, Nobuchika; Okada, Satomi
2016-06-01
In light of the recent Planck 2015 results for the measurement of the cosmic microwave background (CMB) anisotropy, we study simple inflationary models in the context of the Gauss–Bonnet (GB) brane-world cosmology. The brane-world cosmological effect modifies the power spectra of scalar and tensor perturbations generated by inflation and causes a dramatic change for the inflationary predictions of the spectral index (n s) and the tensor-to-scalar ratio (r) from those obtained in the standard cosmology. In particular, the predicted r values in the inflationary models favored by the Planck 2015 results are suppressed due to the GB brane-world cosmological effect, which is in sharp contrast with inflationary scenario in the Randall–Sundrum brane-world cosmology, where the r values are enhanced. Hence, these two brane-world cosmological scenarios are distinguishable. With the dramatic change of the inflationary predictions, the inflationary scenario in the GB brane-world cosmology can be tested by more precise measurements of n s and future observations of the CMB B-mode polarization.
Gravitational field equations on and off a 3-brane world
NASA Astrophysics Data System (ADS)
Aliev, A. N.; Gümrükçüoglu, A. E.
2004-11-01
The effective gravitational field equations on and off a 3-brane world possessing a &Z_{2}; mirror symmetry and embedded in a five-dimensional bulk spacetime with cosmological constant were derived by Shiromizu, Maeda and Sasaki (SMS) in the framework of the Gauss Codazzi projective approach with the subsequent specialization to the Gaussian normal coordinates in the neighbourhood of the brane. However, the Gaussian normal coordinates imply a very special slicing of spacetime and clearly, the consistent analysis of the brane dynamics would benefit from complete freedom in the slicing of spacetime, pushing the layer surfaces in the fifth dimension at any rates of evolution and in arbitrary positions. We rederive the SMS effective gravitational field equations on a 3-brane and generalize the off-brane equations to the case where there is an arbitrary energy momentum tensor in the bulk. We use a more general setting to allow for acceleration of the normals to the brane surface through the lapse function and the shift vector in the spirit of Arnowitt, Deser and Misner. We show that the gravitational influence of the bulk spacetime on the brane may be described by a traceless second-rank tensor &W_{ij};, constructed from the 'electric' part of the bulk Riemann tensor. We also present the evolution equations for the tensor &W_{ij};, as well as for the corresponding 'magnetic' part of the bulk curvature. These equations involve terms determined by both the nonvanishing acceleration of normals in the nongeodesic slicing of spacetime and the presence of other fields in the bulk.
Brane-world stars with a solid crust and vacuum exterior
NASA Astrophysics Data System (ADS)
Ovalle, Jorge; Gergely, László Á.; Casadio, Roberto
2015-02-01
The minimal geometric deformation approach is employed to show the existence of brane-world stellar distributions with a vacuum Schwarzschild exterior, thus without energy leaking from the exterior of the brane-world star into the extra dimension. The interior satisfies all the elementary criteria of physical acceptability for a stellar solution, namely, it is regular at the origin, the pressure and density are positive and decrease monotonically with increasing radius, and all energy conditions are fulfilled. A very thin solid crust with negative radial pressure separates the interior from the exterior, having a thickness Δ inversely proportional to both the brane tension σ and the radius R of the star, i.e. {{Δ }-1}˜ Rσ . This brane-world star with Schwarzschild exterior would appear only thermally radiating to a distant observer and be fully compatible with the stringent constraints imposed on stellar parameters by observations of gravitational lensing, orbital evolutions or properties of accretion disks.
Power Law Inflation and the Cosmic No Hair Theorem in Brane World
Paul, B. C.; Beesham, A.
2006-11-03
We study the cosmic no hair theorem for anisotropic Bianchi models that admit power law inflation with a scalar field in the framework of Brane world. The power law inflationary solution obtained here is driven by the curvature term in the modified field equation in Brane. It is found that all Bianchi models except Bianchi type IX, transit to an inflationary regime with vanishing anisotropy. We note that in the Brane world anisotropic universe isotropizes much faster than that in the general theory of relativity.
Compact stars in Kaluza -Klein World
NASA Astrophysics Data System (ADS)
Gábor Barnaföldi, Gergely; Lévai, Péter; Lukács, Béla
2010-03-01
Unification and geometrization of interactions has been extensively studied during the XX. century. In this short contribution we investigated the possible effect of an extra compactified dimension (alias hypercharge) on a flavor dependent gravitational potential, proposed by Fischbach et al.. We estimated the deviation from the 3 + 1 dimensional scheme and found that, although the deviation is moderate, for celestial compact object it may be higher by orders of magnitude than in terrestrial laboratory measurements.
Magnetic monopoles in Kaluza Klein theory
Sundaresan, M.K.; Tanaka, K.
1985-01-01
We start with an introduction to magnetic monopoles and then discuss the magnetic monopoles in 5-dimensions, the stability of solution with respect to small changes in the metric, and finally end with remarks.
Kaluza-Klein monopoles in five dimensions
Sundaresan, M.K.; Tanaka, K.
1986-01-15
We obtain the general perturbation of the metric belonging to a given q,l,m, and parity of the monopole harmonics. We examine the stability of the monopole solution against small perturbation of the metric.
New branch of Kaluza-Klein compactification
Kinoshita, Shunichiro
2007-12-15
We found a new branch of solutions in Freund-Rubin type flux compactifications. The geometry of these solutions is described as the external space which has a de Sitter symmetry and the internal space which is topologically spherical. However, it is not a simple form of dS{sub p}xS{sup q} but a warped product of de Sitter space and a deformed sphere. We explicitly constructed numerical solutions for a specific case with p=4 and q=4. We show that the new branch of solutions emanates from the marginally stable solution in the branch of dS{sub 4}xS{sup 4} solutions.
Brane-world stars from minimal geometric deformation, and black holes
NASA Astrophysics Data System (ADS)
Casadio, Roberto; Ovalle, Jorge
2014-02-01
Using the effective four-dimensional Einstein field equations, we build analytical models of spherically symmetric stars in the brane-world, in which the external space-time contains both an ADM mass and a tidal charge. In order to determine the interior geometry, we apply the principle of minimal geometric deformation, which allows one to map general relativistic solutions to solutions of the effective four-dimensional brane-world equations. We further restrict our analysis to stars with a radius linearly related to the total general relativistic mass, and obtain a general relation between the latter, the brane-world ADM mass and the tidal charge. In these models, the value of the star's radius can then be taken to zero smoothly, thus obtaining brane-world black hole metrics with a tidal charge solely determined by the mass of the source and the brane tension. We find configurations which entail a partial screening of the gravitational mass, and general conclusions regarding the minimum mass for semiclassical black holes are also drawn.
Classical tests of general relativity: Brane-world Sun from minimal geometric deformation
NASA Astrophysics Data System (ADS)
Casadio, R.; Ovalle, J.; da Rocha, Roldão
2015-05-01
We consider a solution of the effective four-dimensional brane-world equations, obtained from the general relativistic Schwarzschild metric via the principle of minimal geometric deformation, and investigate the corresponding signatures stemming from the possible existence of a warped extra-dimension. In particular, we derive bounds on an extra-dimensional parameter, closely related with the fundamental gravitational length, from the experimental results of the classical tests of general relativity in the Solar system.
Decay of massive Dirac hair on a brane-world black hole
Gibbons, Gary W.; Rogatko, Marek; Szyplowska, Agnieszka
2008-03-15
We investigate the intermediate and late-time behavior of the massive Dirac spinor field in the background of static spherically symmetric brane-world black hole solutions. The intermediate asymptotic behavior of the massive spinor field exhibits a dependence on the field's parameter mass as well as the multiple number of the wave mode. On the other hand, the late-time behavior power-law decay has a rate which is independent of those factors.
Variable-speed-of-light cosmology from the brane world scenario
NASA Astrophysics Data System (ADS)
Youm, Donam
2001-10-01
We argue that the four-dimensional universe on the TeV brane of the Randall-Sundrum scenario takes the bimetric structure of Clayton and Moffat, with gravitons traveling faster than photons instead, while the radion varies with time. We show that such a brane world bimetric model can thereby solve the flatness and cosmological constant problems, provided the speed of a graviton decreases to the present day value rapidly enough. The resolution of other cosmological problems such as the horizon problem and the monopole problem requires supplementation by inflation, which may be achieved by the radion field provided the radion potential satisfies the slow-roll approximation.
On the localization of four-dimensional brane-world black holes
NASA Astrophysics Data System (ADS)
Kanti, P.; Pappas, N.; Zuleta, K.
2013-12-01
In the context of brane-world models, we pursue the question of the existence of five-dimensional solutions describing regular black holes localized close to the brane. Employing a perturbed Vaidya-type line-element embedded in a warped fifth dimension, we attempt to localize the extended black-string singularity, and to restore the regularity of the AdS spacetime at a finite distance from the brane by introducing an appropriate bulk energy-momentum tensor. As a source for this bulk matter, we are considering a variety of non-ordinary field-theory models of scalar fields either minimally coupled to gravity, but including non-canonical kinetic terms, mixing terms, derivative interactions and ghosts, or non-minimally coupled to gravity through a general coupling to the Ricci scalar. In all models considered, even in those characterized by a high degree of flexibility, a negative result was reached. Our analysis demonstrates how difficult the analytic construction of a localized brane-world black hole may be in the context of a well-defined field-theory model. Finally, with regard to the question of the existence or not of a static classical black-hole solution on the brane, our analysis suggests that such solutions could in principle exist; however, the associated field configuration itself has to be dynamic.
Black strings from minimal geometric deformation in a variable tension brane-world
NASA Astrophysics Data System (ADS)
Casadio, R.; Ovalle, J.; da Rocha, Roldão
2014-02-01
We study brane-world models with variable brane tension and compute corrections to the horizon of a black string along the extra dimension. The four-dimensional geometry of the black string on the brane is obtained by means of the minimal geometric deformation approach, and the bulk corrections are then encoded in additional terms involving the covariant derivatives of the variable brane tension. Our investigation shows that the variable brane tension strongly affects the shape and evolution of the black string horizon along the extra dimension, at least in a near-brane expansion. In particular, we apply our general analysis to a model motivated by the Eötvös branes, where the variable brane tension is related to the Friedmann-Robertson-Walker brane-world cosmology. We show that for some stages in the evolution of the universe, the black string warped horizon collapses to a point and the black string has correspondingly finite extent along the extra dimension. Furthermore, we show that in the minimal geometric deformation of a black hole on the variable tension brane, the black string has a throat along the extra dimension, whose area tends to zero as time goes to infinity.
How a Randall-Sundrum Brane-World Effective Potential Influences Inflation Physics
Beckwith, A. W.
2007-01-30
In string theory, even when there are ten to the thousand power vacuum states, does inflation produce overwhelmingly one preferred type of vacuum state? We respond affirmatively to questions whether existence of graviton production is confirmable using present detector methodology. We use an explicit Randall-Sundrum brane-world effective potential as congruent with an inflationary quadratic potential start. This occurs after Bogomolnyi inequality eliminates need for ad hoc assumption of axion wall mass high temperature related disappearing. Graviton production has explicit links with a five-dimensional brane-world negative cosmological constant and a four-dimensional positive valued cosmological constant, whose temperature dependence permits an early universe graviton production activity burst. We show how di quarks, wave functions, and various forms tie into the Wheeler-De Witt equation. This permits investigating a discretized quantum bounce and a possible link to the initial phases of present universe's evolution with a prior universe's collapse to the bounce point--the initial starting point to inflationary expansion. This opens a possibility of realistically investigating gravitons as part of a space propulsion system and dealing with problems from a beam of gravity waves, which would create a g-force because the geodestic structure is near field. It can be applied to existing and to new space propulsion concepts.
Probing topologically charged black holes on brane worlds in f({R}) bulk
NASA Astrophysics Data System (ADS)
Kuerten, André M.; da Rocha, Roldão
2016-07-01
The perihelion precession, the deflection of light and the radar echo delay are classical tests of General Relativity here used to probe brane-world topologically charged black holes in a f(R) bulk. Moreover, such tests are used to constrain the parameter that arises from the Shiromizu-Maeda-Sasaki procedure applied to a f(R) bulk. Observational data constrain the possible values of the tidal charge parameter and the effective cosmological constant in this context. We show that the observational/experimental data for both perihelion precession and radar echo delay make the black hole parameters to be more strict than the ones for the DMPR black hole. Moreover, the deflection of light constrains the tidal charge parameter similarly as the DMPR black holes, due to a peculiarity in the equation of motion.
CASIMIR Effect in a Supersymmetry-Breaking Brane-World as Dark Energy
Chen, P
2004-09-29
A new model for the origin of dark energy is proposed based on the Casimir effect in a supersymmetry-breaking brane-world. Supersymmetry is assumed to be preserved in the bulk while broken on a 3-brane. Due to the boundary conditions imposed on the compactified extra dimensions, there is an effective Casimir energy induced on the brane. The net Casimir energy contributed from the graviton and the gravitino modes as a result of supersymmetry-breaking on the brane is identified as the observed dark energy, which in our construction is a cosmological constant. We show that the smallness of the cosmological constant, which results from the huge contrast in the extra-dimensional volumes between that associated with the 3-brane and that of the bulk, is attainable under very relaxed condition.
Brane-world and loop cosmology from a gravity-matter coupling perspective
NASA Astrophysics Data System (ADS)
Olmo, Gonzalo J.; Rubiera-Garcia, D.
2015-01-01
We show that the effective brane-world and the loop quantum cosmology background expansion histories can be reproduced from a modified gravity perspective in terms of an f (R) gravity action plus a g (R) term non-minimally coupled with the matter Lagrangian. The reconstruction algorithm that we provide depends on a free function of the matter density that must be specified in each case and allows to obtain analytical solutions always. In the simplest cases, the function f (R) is quadratic in the Ricci scalar, R, whereas g (R) is linear. Our approach is compared with recent results in the literature. We show that working in the Palatini formalism there is no need to impose any constraint that keeps the equations second-order, which is a key requirement for the successful implementation of the reconstruction algorithm.
Extra dimensions at the CERN LHC via mini-black holes: Effective Kerr-Newman brane-world effects
Rocha, R. da; Coimbra-Araujo, C. H.
2006-09-01
We solve Einstein equations on the brane to derive the exact form of the brane-world-corrected perturbations in Kerr-Newman singularities, using Randall-Sundrum and Arkani-Hamed-Dimopoulos-Dvali (ADD) models. It is a consequence of such models that Kerr-Newman mini-black holes can be produced in LHC. We use this approach to derive a normalized correction for the Schwarzschild Myers-Perry radius of a static (4+n)-dimensional mini-black hole, using more realistic approaches arising from Kerr-Newman mini-black hole analysis. Besides, we prove that there are four Kerr-Newman black hole horizons in the brane-world scenario we use, although only the outer horizon is relevant in the physical measurable processes. Parton cross sections in LHC and Hawking temperature are also investigated as functions of Planck mass (in the LHC range 1-10 TeV), mini-black hole mass, and the number of large extra dimensions in brane-world large extra-dimensional scenarios. In this case a more realistic brane-effect-corrected formalism can achieve more precisely the effective extra-dimensional Planck mass and the number of large extra dimensions--in the Arkani-Hamed-Dimopoulos-Dvali model--or the size of the warped extra dimension--in Randall-Sundrum formalism.
Developed Adomian method for quadratic Kaluza-Klein relativity
NASA Astrophysics Data System (ADS)
Azreg-Aïnou, Mustapha
2010-01-01
We develop and modify the Adomian decomposition method (ADecM) to work for a new type of nonlinear matrix differential equations (MDE's) which arise in general relativity (GR) and possibly in other applications. The approach consists in modifying both the ADecM linear operator with highest order derivative and ADecM polynomials. We specialize in the case of a 4 × 4 nonlinear MDE along with a scalar one describing stationary cylindrically symmetric metrics in quadratic five-dimensional GR, derive some of their properties using ADecM and construct the most general unique power series solutions. However, because of the constraint imposed on the MDE by the scalar one, the series solutions terminate in closed forms exhausting all possible solutions.
NASA Astrophysics Data System (ADS)
Fischer-Hjalmars, Inga; Laurent, Bertel
2014-03-01
Oskar Klein died on the fifth of February 1977 at the age of eighty-two. One of the most prominent Swedish physicists ever and an outstanding personality in the field of culture had passed away. He was a man whose interests knew no limits and as a scientist he greatly enriched our understanding of Nature. All those who knew him were astounded by his profound thinking, wealth of ideas, extensive insight and humanism, qualities that obviously had been stimulated by the spirit in his parents' home. His father, rabbi and professor in Stockholm, was deeply engaged in theological and humanitarian issues...
Wurthmann, C; Klieser, E
1991-05-01
The Kleine-Levin syndrome is generally considered to be a benign functional disorder of hypothalamic structures. Its onset is usually in adolescence. The most characteristic symptoms are periodic hypersomnia, excessive eating, hypersexuality, irritability and apathy. Associated features are depressive and schizophrenic symptoms. A biological relationship between the Klein-Levin syndrome and endogenous psychoses is discussed. PMID:1869237
Foerste, Stefan; Nilles, Hans Peter; Vaudrevange, Patrick; Wingerter, Akin
2004-11-15
Orbifold compactification of heterotic E{sub 8}xE{sub 8}{sup '} string theory is a source for promising grand unified model building. It can accommodate the successful aspects of grand unification while avoiding problems like doublet-triplet splitting in the Higgs sector. Many of the phenomenological properties of the four-dimensional effective theory find an explanation through the geometry of compact space and the location of matter and Higgs fields. These geometrical properties can be used as a guideline for realistic model building.
Miglis, Mitchell G; Guilleminault, Christian
2016-06-01
Kleine-Levin syndrome is a rare recurrent hypersomnia associated with symptoms of behavioral and cognitive impairment. This article reviews common presenting symptoms, differential diagnosis, diagnostic workup, and potential treatment options. Current updates on functional imaging studies and long-term neuropsychological studies are reviewed. PMID:27137943
Generalized Klein-Kramers equations
NASA Astrophysics Data System (ADS)
Fa, Kwok Sau
2012-12-01
A generalized Klein-Kramers equation for a particle interacting with an external field is proposed. The equation generalizes the fractional Klein-Kramers equation introduced by Barkai and Silbey [J. Phys. Chem. B 104, 3866 (2000), 10.1021/jp993491m]. Besides, the generalized Klein-Kramers equation can also recover the integro-differential Klein-Kramers equation for continuous-time random walk; this means that it can describe the subdiffusive and superdiffusive regimes in the long-time limit. Moreover, analytic solutions for first two moments both in velocity and displacement (for force-free case) are obtained, and their dynamic behaviors are investigated.
Arnulf, Isabelle
2015-06-01
Kleine-Levin syndrome is a rare recurrent encephalopathy primarily affecting teenagers, characterized by relapsing-remitting episodes of hypersomnia along with cognitive, psychiatric and behavioral disturbances. During episodes, patients suddenly present hypersomnia (with sleep lasting 15-21 h/d), cognitive impairment (major apathy, confusion, slowness, amnesia), and a specific feeling of derealization (dreamy state, altered perception). Less frequently, they may also experience hyperphagia (66%), hypersexuality (53%, principally men), depressed mood (53%, principally women), anxiety, hallucinations, and acute brief psychosis (33%). Brain functional imaging is often abnormal. Stimulants are poorly beneficial during episodes, whereas lithium and valproate help reducing the episodes frequency and duration. PMID:26055863
Hyperbolic Kac-Moody algebras and chaos in Kaluza-Klein models
NASA Astrophysics Data System (ADS)
Damour, T.; Henneaux, M.; Julia, B.; Nicolai, H.
2001-06-01
Some time ago, it was found that the never-ending oscillatory chaotic behaviour discovered by Belinskii, Khalatnikov and Lifshitz (BKL) for the generic solution of the vacuum Einstein equations in the vicinity of a spacelike (``cosmological'') singularity disappears in spacetime dimensions /D≡d+1>10. Recently, a study of the generalization of the BKL chaotic behaviour to the superstring effective Lagrangians has revealed that this chaos is rooted in the structure of the fundamental Weyl chamber of some underlying hyperbolic Kac-Moody algebra. In this Letter we show that the same connection applies to pure gravity in any spacetime dimension />=4, where the relevant algebras are AEd. In this way the disappearance of chaos in pure gravity models in /D>=11 dimensions becomes linked to the fact that the Kac-Moody algebras AEd are no longer hyperbolic for /d>=10.
Equations of motion and fifth force in a general Kaluza-Klein space
NASA Astrophysics Data System (ADS)
Bejancu, Aurel
2013-11-01
In this paper we present a new point of view on space-time-matter (STM) theory. First, some weak points from earlier research papers on STM theory are presented. Then, we obtain in a covariant form the fully general equations of motion for STM theory. This enables us to classify the motions and to give a new definition of the fifth force in physics.
Microstates of the D1-D5-Kaluza-Klein monopole system
Bena, Iosif; Kraus, Per
2005-07-15
We find supergravity solutions corresponding to all U(1)xU(1) invariant chiral primaries of the D1-D5-KK system. These solutions are 1/8 BPS, carry angular momentum, and are asymptotically flat in the 3+1 dimensional sense. They can be thought of as representing the ground states of the four-dimensional black hole constructed from the D1-D5-KK-P system. Demanding the absence of unphysical singularities in our solutions determines all free parameters, and gives precise agreement with the quantum numbers expected from the CFT point of view. The physical mechanism behind the smoothness of the solutions is that the D1 branes and D5 branes expand into a KK-monopole supertube in the transverse space of the original KK monopole.
Pre-big bang collapsing universe from modern Kaluza-Klein theory of gravity
NASA Astrophysics Data System (ADS)
Bellini, Mauricio
2011-11-01
We study the collapse of the universe described by a scalar field spherically symmetric collapse of a system described by a massless scalar field from a 5D Riemann-flat canonical metric, on which we make a dynamical foliation on the extra space-like dimension. The asymptotic universe (absent of singularities) results to be finite in size and energy density, with an vacuum dominated equation of state. The important result here obtained is that the asymptotic back-reaction effects are given by a negative constant: 1 2 [ 1 1 + ψ ˙ + 1 ψ ˙ ] < ( > + 1 2 a 2 < ( ∇ > | = - 8 Λ 3 π G .
Tunnelling of scalar and Dirac particles from squashed charged rotating Kaluza-Klein black holes
NASA Astrophysics Data System (ADS)
Stetsko, M. M.
2016-02-01
The thermal radiation of scalar particles and Dirac fermions from squashed charged rotating five-dimensional black holes is considered. To obtain the temperature of the black holes we use the tunnelling method. In the case of scalar particles we make use of the Hamilton-Jacobi equation. To consider tunnelling of fermions the Dirac equation was investigated. The examination shows that the radial parts of the action for scalar particles and fermions in the quasi-classical limit in the vicinity of horizon are almost the same and as a consequence it gives rise to identical expressions for the temperature in the two cases.
NASA Technical Reports Server (NTRS)
Klein, Gary
2004-01-01
Gary Klein, PH.D., is chief scientist of Klein Associates, Inc., a company he founded in 1978 to better understand how to improve decision making in individuals and teams. The company has 30 employees working on projects for both government and commercial clients. Dr. Klein is one of the founders of the field of naturalistic decision making. His work on recognitional decision making has been influential for the design of new systems and interfaces, and for the development of decision training programs. He has extended his work on decision making to describe problem detection, opinion generation, sense making, and planning.
NASA Astrophysics Data System (ADS)
Chamblin, A.; Hawking, S. W.; Reall, H. S.
2000-03-01
Gravitational collapse of matter trapped on a brane will produce a black hole on the brane. We discuss such black holes in the models of Randall and Sundrum where our universe is viewed as a domain wall in five-dimensional anti-de Sitter space. We present evidence that a non-rotating uncharged black hole on the domain wall is described by a ``black cigar'' solution in five dimensions.
Brane worlds in critical gravity
NASA Astrophysics Data System (ADS)
Chen, Feng-Wei; Liu, Yu-Xiao; Zhong, Yuan; Wang, Yong-Qiang; Wu, Shao-Feng
2013-11-01
Recently, Lü and Pope proposed critical gravities in [Phys. Rev. Lett. 106, 181302 (2011)]. In this paper we construct analytic brane solutions in critical gravity with matter. The Gibbons-Hawking surface term and junction condition are investigated, and the thin and thick brane solutions are obtained. All these branes are embedded in five-dimensional anti-de Sitter spacetimes. Our solutions are stable against scalar perturbations, and the zero modes of scalar perturbations cannot be localized on the branes.
Suwayri, Saad M. Al
2016-01-01
Objectives: To highlight the occurrence of familial cases and addresses, whether familial Kleine-Levine syndrome (KLS) presents the same spectrum of disease, as that seen in sporadic KLS. Methods: Between September and December 2014, reports of familial cases of KLS were identified by searching the Library of Congress, PubMed, and Web of Science databases restricted to the English language, with no restriction on date of publication. All cases were reviewed to identify familial cases consistent with current diagnostic criteria for sporadic KLS. Results: Six reviews and 11 case reports describing cases of familial KLS were identified. In 17 of the 29 familial cases identified, sufficient clinical details were described to be confident that these cases were familial and consistent with the description of KLS in the International Classification of Sleep Disorders 3rd edition (ICSD-3), and recent detailed reviews of sporadic KLS. Conclusion: A significant number of familial cases of KLS have been described that are consistent with the ICSD-3 description of KLS, and indistinguishable from sporadic KLS. This suggests that study of familial KLS using modern genetic techniques may be useful in elucidating the pathogenesis of this rare condition. PMID:26739970
Theodor Kaluza and His Five-Dimensional World
NASA Astrophysics Data System (ADS)
Wuensch, Daniela
2006-02-01
Theodor Kaluza (1885-1954) attracted the attention of the physical community in 1921 with his unified field theory of gravitation and electromagnetism in five dimensions. Despite Einstein's great interest in Kaluza's theory, 50 years elapsed before it contributed toward a paradigm shift in modern theoretical physics. The biography of this unknown scientist is briefly presented along with an outline of his four physical theories. There follows a short discussion of Kaluza's five-dimensional unified field theory and the impression it made on Einstein.
Newton–Cartan, Galileo–Maxwell and Kaluza–Klein
NASA Astrophysics Data System (ADS)
Van den Bleeken, Dieter; Yunus, Çağin
2016-07-01
We study Kaluza–Klein reduction in Newton–Cartan gravity. In particular we show that dimensional reduction and the nonrelativistic limit commute. The resulting theory contains Galilean electromagnetism and a nonrelativistic scalar. It provides the first example of back-reacted couplings of scalar and vector matter to Newton–Cartan gravity. This back-reaction is interesting as it sources the spatial Ricci curvature, providing an example where nonrelativistic gravity is more than just a Newtonian potential.
NASA Astrophysics Data System (ADS)
Ekspong, Gösta
2014-03-01
During the 1920's the Compton effect was very much at the centre of interest among physicists due to its demonstration of the inadequacy of the classical theory for light when trying to account for the scattering of X-rays. The angular intensity distribution of scattered X-rays had not been successfully described by theory until Oskar Klein and Yoshio Nishina in 1928 solved the problem using the then new Dirac theory for the electron. The present paper gives an account of the collaboration in the summer of 1928 between the two physicists -- one a theorist, the other an experimentalist -- when both were visitors at the Niels Bohr Institute in Copenhagen.
Visscher, F; Smit, L M; Smith, F; Boer, F; Njiokiktjien, C
1989-12-01
Two boys, aged 12 and 13 years, showed relapsing periods of somnolence and excessive eating, starting after a viral illness. One of them also showed periodic disturbance of sexual impulse control. The symptomatic periods were followed by symptom-free intervals in a highly characteristic pattern. This gave the clue to the diagnosis Kleine-Levin syndrome. The cause of this syndrome is unknown, in some cases a relationship between infectious disease or traumatic brain damage has been postulated. A dysfunction of the hypothalamus and associated structures is suspected. The syndrome has a rather favourable prognosis. The symptoms can be relieved by amphetamines, methylphenidate and probably also by lithium carbonate. PMID:2617509
Klein factors and Fermi-Bose equivalence
NASA Astrophysics Data System (ADS)
Lee, Taejin
2016-06-01
Generalizing the kink operator of the Heisenberg spin 1/2 model, we construct a set of Klein factors explicitly such that (1+1)-dimensional fermion theories with an arbitrary number of species are mapped onto the corresponding boson theories with the same number of species and vice versa. The actions for the resultant theories do not possess a nontrivial Klein factor. With this set of Klein factors, we are also able to map the simple boundary states, such as the Neumann and the Dirichlet boundary states, of the fermion (boson) theory onto those of the boson (fermion) theory. Applications of the Fermi-Bose equivalence with the constructed Klein factors to well-known (1+1)-dimensional theories have been discussed.
Kleine-Levin syndrome: a review
Miglis, Mitchell G; Guilleminault, Christian
2014-01-01
Kleine-Levin syndrome is a recurrent hypersomnia associated with symptoms of hyperphagia, hypersexuality, and cognitive impairment. This article reviews the current available research and describes common clinical symptoms, differential diagnosis, and acceptable workup and treatment. Although deficits have traditionally been thought to resolve between episodes, functional imaging studies and long-term neuropsychological testing in select patients have recently challenged this notion. This may suggest that Kleine-Levin syndrome is not as benign as previously considered. PMID:24470783
Kleine-Levin syndrome: a review.
Miglis, Mitchell G; Guilleminault, Christian
2014-01-01
Kleine-Levin syndrome is a recurrent hypersomnia associated with symptoms of hyperphagia, hypersexuality, and cognitive impairment. This article reviews the current available research and describes common clinical symptoms, differential diagnosis, and acceptable workup and treatment. Although deficits have traditionally been thought to resolve between episodes, functional imaging studies and long-term neuropsychological testing in select patients have recently challenged this notion. This may suggest that Kleine-Levin syndrome is not as benign as previously considered. PMID:24470783
A note on Clifford-Klein forms
NASA Astrophysics Data System (ADS)
Jastrzȩbski, P.; Tralle, A.
2014-09-01
We consider the problem of finding Clifford-Klein forms in a class of homogeneous spaces determined by inclusions of real Lie algebras of a special type which we call strongly regular. This class of inclusions is described in terms of their Satake diagrams. For example, the complexifications of such inclusions contain the class of subalgebras generated by automorphisms of finite order. We show that the condition of strong regularity implies the restriction on the real rank of subalgebras. This in part explains why the known examples of Clifford-Klein forms are rare. We make detailed calculations of some known examples from the point of view of the Satake diagrams.
Bosonic analog of the Klein paradox
Wagner, R. E.; Ware, M. R.; Su, Q.; Grobe, R.
2010-02-15
The standard Klein paradox describes how an incoming electron scatters off a supercritical electrostatic barrier that is so strong that it can generate electron-positron pairs. This fermionic system has been widely discussed in textbooks to illustrate some of the discrepancies between quantum mechanical and quantum field theoretical descriptions for the pair creation process. We compare the fermionic dynamics with that of the corresponding bosonic system. We point out that the direct counterpart of the Pauli exclusion principle (the central mechanism to resolve the fermionic Klein paradox) is stimulated emission, which leads to the resolution of the analogous bosonic paradox.
Gauge field localization on brane worlds
Guerrero, Rommel; Rodriguez, R. Omar; Melfo, Alejandra; Pantoja, Nelson
2010-04-15
We consider the effects of spacetime curvature and brane thickness on the localization of gauge fields on a brane via kinetic terms induced by localized fermions. We find that in a warped geometry with an infinitely thin brane, both the infrared and the ultraviolet behavior of the electromagnetic propagator are affected, providing a more stringent bound on the brane's tension than that coming from the requirement of four-dimensional gravity on the brane. On the other hand, for a thick wall in a flat spacetime, where the fermions are localized by means of a Yukawa coupling, we find that four-dimensional electromagnetism is recovered in a region bounded from above by the same critical distance appearing in the thin case, but also from below by a new scale related to the brane's thickness and the electromagnetic couplings. This imposes very stringent bounds on the brane's thickness which seem to invalidate the localization mechanism for this case.
Brane world in non-Riemannian geometry
Maier, R.; Falciano, F. T.
2011-03-15
We carefully investigate the modified Einstein's field equation in a 4-dimensional (3-brane) arbitrary manifold embedded in a 5-dimensional non-Riemannian bulk spacetime with a noncompact extra dimension. In this context the Israel-Darmois matching conditions are extended assuming that the torsion in the bulk is continuous. The discontinuity in the torsion first derivatives are related to the matter distribution through the field equation. In addition, we develop a model that describes a flat FLRW model embedded in a 5-dimensional de Sitter or anti-de Sitter, where a 5-dimensional cosmological constant emerges from the torsion.
Warped brane worlds in critical gravity
NASA Astrophysics Data System (ADS)
Zhong, Yi; Chen, Feng-Wei; Xie, Qun-Ying; Liu, Yu-Xiao
2014-12-01
We investigate the brane models in arbitrary dimensional critical gravity presented in Lu and Pope (Phys Rev Lett 106:181302, 2011). For the models of the thin branes with codimension one, the Gibbons-Hawking surface term and the junction conditions are derived, with which the analytical solutions for the flat, AdS, and dS branes are obtained at the critical point of the critical gravity. It is found that all these branes are embedded in an AdS spacetime, but, in general, the effective cosmological constant of the AdS spacetime is not equal to the naked one in the critical gravity, which can be positive, zero, and negative. Another interesting result is that the brane tension can also be positive, zero, or negative, depending on the symmetry of the thin brane and the values of the parameters of the theory, which is very different from the case in general relativity. It is shown that the mass hierarchy problem can be solved in the braneworld model in the higher-derivative critical gravity. We also study the thick brane model and find analytical and numerical solutions of the flat, AdS, and dS branes. It is found that some branes will have inner structure when some parameters of the theory are larger than their critical values, which may result in resonant KK modes for some bulk matter fields. The flat branes with positive energy density and AdS branes with negative energy density are embedded in an -dimensional AdS spacetime, while the dS branes with positive energy density are embedded in an -dimensional Minkowski one.
Lateral boundary conditions for the Klein-Gordon-Fock equation
NASA Astrophysics Data System (ADS)
Tulenov, Kanat S.; Dauitbek, Dostilek
2016-08-01
In this paper we consider an initial-boundary value problem for the Klein-Gordon-Fock equation. We prove the uniqueness of the solution and find lateral boundary conditions for the Klein-Gordon-Fock equation.
Influence of graviton on top-antitop production at the LHC
NASA Astrophysics Data System (ADS)
Smolek, K.; Arai, M.; Okada, N.; Šimák, V.
2008-05-01
We examine the top quark production in the brane world scenario. We study two typical models - the model proposed by Arkani-Hamed, Dimopoulos and Dvali (ADD) and the model of Randall and Sundrum (RS). In addition to the Standard Model processes, there is a new contribution to the top-antitop pair production process mediated by graviton Kaluza-Klein modes in the s-channel. We calculated the density matrix for the top-antitop pair production including the new contribution. With a reasonable parameter choice, we find a sizable deviation of the top-antitop quark spin correlations from those in the Standard Model.
General self-tuning solutions and no-go theorem
Förste, Stefan; Kim, Jihn E.; Lee, Hyun Min E-mail: jihnekim@gmail.com
2013-03-01
We consider brane world models with one extra dimension. In the bulk there is in addition to gravity a three form gauge potential or equivalently a scalar (by generalisation of electric magnetic duality). We find classical solutions for which the 4d effective cosmological constant is adjusted by choice of integration constants. No go theorems for such self-tuning mechanism are circumvented by unorthodox Lagrangians for the three form respectively the scalar. It is argued that the corresponding effective 4d theory always includes tachyonic Kaluza-Klein excitations or ghosts. Known no go theorems are extended to a general class of models with unorthodox Lagrangians.
Annihilation cross section of Kaluza Klien dark matter
Sharma, Rakesh; Upadhyaya, G. K. Sharma, S.
2015-07-31
The question as to how this universe came into being and as to how it has evolved to its present stage, is an old question. The answer to this question unfolds many secrets regarding fundamental particles and forces between them. Theodor Kaluza proposed the concept that the universe is composed of more than four space-time dimensions. In his work, electromagnetism is united with gravity. Various extra dimension formulations have been proposed to solve a variety of problems. Recently, the idea of more than four space time dimensions is applied to the search for particle identity of dark matter (DM). Signature of dark matter can be revealed by analysis of very high energy electrons which are coming from outer space. We investigate recent advancement in the field of dark matter search with reference to very high energy electrons from outer space [1-8].
Barrier paradox in the Klein zone
De Leo, Stefano; Rotelli, Pietro P.
2006-04-15
We study the solutions for a one-dimensional electrostatic potential in the Dirac equation when the incoming wave packet exhibits the Klein paradox (pair production). With a barrier potential we demonstrate the existence of multiple reflections (and transmissions). The antiparticle solutions which are necessarily localized within the barrier region create new pairs with each reflection at the potential walls. Consequently we encounter a new 'paradox' for the barrier because successive outgoing wave amplitudes grow geometrically.
Martin J. Klein: From Physicist to Historian
NASA Astrophysics Data System (ADS)
Hu, Danian
2012-12-01
To his friends, colleagues, and students, Martin Klein was a gentle and modest man of extraordinary integrity whose stellar accomplishments garnered him many honors. I sketch his life and career, in which he transformed himself from a theoretical physicist at Columbia University, the Massachusetts Institute of Technology, and the Case Institute of Technology into a historian of physics while on leave at the Dublin Institute for Advanced Study and the University of Leiden and then pursued this field full time at Yale University.
Adrian Stokes and the portrait of Melanie Klein.
Sayers, Janet
2015-08-01
This paper focuses on the offer by the art writer Adrian Stokes to commission and pay for a portrait of the psychoanalyst Melanie Klein by the artist William Coldstream. It details some of the precursors of this offer in Stokes's preceding involvement first with Klein and then with Coldstream; her response to this offer; and its outcome and aftermath in Stokes's subsequent writing about Klein and Coldstream. PMID:25989030
Klein-Gordon Equation in Hydrodynamical Form
Wong, Cheuk-Yin
2010-01-01
We follow and modify the Feshbach-Villars formalism by separating the Klein-Gordon equation into two coupled time-dependent Schroedinger equations for the particle and antiparticle wave functions with positive probability densities. We find that the equation of motion for the probability densities is in the form of relativistic hydrodynamics where various forces have their physical and classical counterparts. An additional element is the presence of the quantum stress tensor that depends on the derivatives of the amplitude of the wave function.
Obituary: Michael John Klein, 1940-2005
NASA Astrophysics Data System (ADS)
Gulkis, Samuel
2006-12-01
Michael John Klein died on 14 May 2005 at home in South Pasadena, California. The cause of death was tongue cancer that metastasized to the lungs. He was a non-smoker. Mike was a passionate radio astronomer, a trusted astronomical observer, an educator and a family man. Mike was born on 19 January 1940 in Ames, Iowa, the son of Florence Marie (Graf) and Fred Michael Klein. His mother was a homemaker, and his father was a banker. Mike had two older sisters, Lois Jean (Klein) Flauher and Marilyn June (Klein) Griffin. In 1962, Mike married his high school sweetheart Barbara Dahlberg, who survives him along with their three children, Kristin Marie (Klein) Shields, Michael John Klein Jr., Timothy Joel Klein, and six grandchildren. Mike developed a love for astronomy early in his life, and credited an early morning, newspaper-delivery route that he had at age twelve, which took him outside well before sunrise. He told family members that as he walked along his route, he stared into the sky and wondered what everything was. He studied sky charts, located stars, and began to understand how the planets shifted their positions relative to the stars each day. Another big influence in Mike's life was his brother in-law, Jim Griffin. Jim helped Mike understand that his passion for science did not have to remain a hobby, but could and should become a career. Jim's encouragement led Mike to attend Iowa State University in Ames, where he earned a BS in electrical engineering in 1962. Mike then started graduate school in electrical engineering at Michigan State, but after one semester transferred to the University of Michigan, Ann Arbor, where he earned an MS (1966) and PhD (1968) in astronomy. His doctoral dissertation, under the direction of Professor Fred Haddock, was based on extensive observations of the planets and examined the physical and thermal properties of planetary atmospheres and surfaces. Mike was awarded a Resident Research Associate position at JPL by the National
A Disorder Unique to Adolescence? The Kleine-Levin Syndrome.
ERIC Educational Resources Information Center
Cawthorn, Paul
1990-01-01
Describes Kleine-Levin syndrome, rare disorder characterized by excessive sleep and abnormal hunger. Notes that, in its pure form, disorder can only be diagnosed in adolescent males. Presents case study of 15-year-old male with disease. Presents evidence which suggests link between Kleine-Levin syndrome and cyclic affective disorders. (Author/ABL)
Cassullo, Gabriele
2016-03-01
Compared to the impact of the work of Melanie Klein on the history of psychoanalysis, the contributions of her daughter, Melitta Schmideberg, passed almost unnoticed. At present, Schmideberg is solely remembered for having harshly attacked her mother at the start of the Controversial Discussions of the British Psycho-Analytical Society and for having coined the fitting expression "stable instability" in order to describe borderline and asocial personality disorders. However, the author discusses how the early groundbreaking discoveries of Klein with regards to primitive anxieties were the result of the joint work and thinking of Melanie and Melitta. Moreover, he argues that the conflict between the two, along with the subsequent polarization of their views, did not facilitate the development of psychoanalysis, neither did it help the analytic community to recognize the value of Melitta's contributions to psychoanalysis. PMID:26912243
The effective action of D6-branes in mathcal{N} = 1 type IIA orientifolds
NASA Astrophysics Data System (ADS)
Kerstan, Max; Weigand, Timo
2011-06-01
We use a Kaluza-Klein reduction to compute the low-energy effective action for the massless modes of a spacetime-filling D6-brane wrapped on a special Lagrangian 3-cycle of a type IIA Calabi-Yau orientifold. The modifications to the characteristic data of the mathcal{N} = 1 bulk orientifold theory in the presence of a D6-brane are analysed by studying the underlying Type IIA supergravity coupled to the brane world volume in the democratic formulation and performing a detailed dualisation procedure. The mathcal{N} = 1 chiralcoordinates are found to be in agreement with expectations from mirror symmetry. We work out the Kähler potential for the chiral superfields as well as the gauge kinetic functions for the bulk and the brane gauge multiplets including the kinetic mixing between the two. The scalar potential resulting from the dualisation procedure can be formally interpreted in terms of a superpotential. Finally, the gauging of the Peccei-Quinn shift symmetries of the complex structure multiplets reproduces the D-term potential enforcing the calibration condition for special Lagrangian 3-cycles.
Perturbative Solutions of the Einstein Klein-Gordon Equations
NASA Astrophysics Data System (ADS)
Puliti, Gianluca; Jennings, Mara; Mamo, Vincent; Vuille, Chris
2005-11-01
As the Klein-Gordon equation is important in quantum theory and describes spin-0 particles, it is of interest to discover the nature of the gravity field such particles would be expected to create. In this paper, we solve the static, massive Einstein-Klein-Gordon (EKG) equations in perturbation, and compare the results with a similar calculation developed for the Einstein-Proca system. Subsequently, we study the massless static Klein-Gordon equation, and compare the result to the Reissner-Nordstrom metric.
Variational principles for eigenvalues of the Klein-Gordon equation
Langer, Matthias; Tretter, Christiane
2006-10-15
In this paper variational principles for eigenvalues of an abstract model of the Klein-Gordon equation with electromagnetic potential are established. They are used to characterize and estimate eigenvalues in cases where the essential spectrum has a gap around 0, even in the presence of complex eigenvalues. As a consequence, a comparison between eigenvalues of the Klein-Gordon equation in R{sup d} and eigenvalues of certain Schroedinger operators is obtained. The results are illustrated on examples including the Klein-Gordon equation with Coulomb and square-well potential.
[Families with recurrent cases of Waardenburg-Klein syndrome].
Bliumina, M G; Moskovkina, A G
1985-06-01
Deaf children with the type I Waardenburg--Klein syndrome were studied. Secondary cases were found in 14 unrelated and 1 incest families. In 10 families probands and all their affected relatives had the type I Waardenburg--Klein syndrome. In 4 families patients were discovered with both type I and type II syndromes. In an incest family the proband seemed to have the type III, while his mother and father (sibs) had type II and their grandmother the type I syndrome. These results contradict the hypothesis claiming the origin of different types of Waardenburg--Klein syndrome to be due to the action of different genes. It is proposed that types I and II, or all types of the syndrome are caused by a single dominant gene. Potential mechanisms for clinical polymorphism of Waardenburg--Klein syndrome are related to incomplete penetrance and varying expression of this gene. PMID:4029612
4. Historic American Buildings Survey, William C. Kleine, Photographer February ...
4. Historic American Buildings Survey, William C. Kleine, Photographer February 10, 1934 SOUTH ELEVATION OF RESIDENCE. - Francis Louis des Mazieres Store Building & House, Martinez & South Alamo Streets, San Antonio, Bexar County, TX
5. Historic American Buildings Survey, William C. Kleine, Photographer February ...
5. Historic American Buildings Survey, William C. Kleine, Photographer February 10, 1934 SOUTH ELEVATION OF STORE. - Francis Louis des Mazieres Store Building & House, Martinez & South Alamo Streets, San Antonio, Bexar County, TX
Fitzpatrick, A Liam; Perez, Gilad; Randall, Lisa
2008-05-01
A variant of a warped extra dimension model is presented. It is based on 5D minimal flavor violation, in which the only sources of flavor breaking are two 5D anarchic Yukawa matrices. These matrices also control the bulk masses, which are responsible for the resulting flavor hierarchy. The theory flows to a next to minimal flavor violation model where flavor violation is dominantly coming from the 3rd generation. Flavor violation is also suppressed by a parameter that dials the violation in the up or down sector. There is therefore a sharp limit in which there is no flavor violation in the down-type quark sector which, remarkably, is consistent with the observed flavor parameters. This is used to eliminate the current Randall-Sundrum flavor and CP problem. Our construction suggests that strong dynamic-based, flavor models may be built based on the same concepts. PMID:18518274
Fitzpatrick, A. Liam; Randall, Lisa; Perez, Gilad
2008-05-02
A variant of a warped extra dimension model is presented. It is based on 5D minimal flavor violation, in which the only sources of flavor breaking are two 5D anarchic Yukawa matrices. These matrices also control the bulk masses, which are responsible for the resulting flavor hierarchy. The theory flows to a next to minimal flavor violation model where flavor violation is dominantly coming from the 3rd generation. Flavor violation is also suppressed by a parameter that dials the violation in the up or down sector. There is therefore a sharp limit in which there is no flavor violation in the down-type quark sector which, remarkably, is consistent with the observed flavor parameters. This is used to eliminate the current Randall-Sundrum flavor and CP problem. Our construction suggests that strong dynamic-based, flavor models may be built based on the same concepts.
NASA Astrophysics Data System (ADS)
Fitzpatrick, A. Liam; Perez, Gilad; Randall, Lisa
2008-05-01
A variant of a warped extra dimension model is presented. It is based on 5D minimal flavor violation, in which the only sources of flavor breaking are two 5D anarchic Yukawa matrices. These matrices also control the bulk masses, which are responsible for the resulting flavor hierarchy. The theory flows to a next to minimal flavor violation model where flavor violation is dominantly coming from the 3rd generation. Flavor violation is also suppressed by a parameter that dials the violation in the up or down sector. There is therefore a sharp limit in which there is no flavor violation in the down-type quark sector which, remarkably, is consistent with the observed flavor parameters. This is used to eliminate the current Randall-Sundrum flavor and CP problem. Our construction suggests that strong dynamic-based, flavor models may be built based on the same concepts.
Relativistic superfluidity and vorticity from the nonlinear Klein-Gordon equation
NASA Astrophysics Data System (ADS)
Xiong, Chi; Good, Michael R. R.; Guo, Yulong; Liu, Xiaopei; Huang, Kerson
2014-12-01
We investigate superfluidity, and the mechanism for creation of quantized vortices, in the relativistic regime. The general framework is a nonlinear Klein-Gordon equation in curved spacetime for a complex scalar field, whose phase dynamics gives rise to superfluidity. The mechanisms discussed are local inertial forces (Coriolis and centrifugal), and current-current interaction with an external source. The primary application is to cosmology, but we also discuss the reduction to the nonrelativistic nonlinear Schrödinger equation, which is widely used in describing superfluidity and vorticity in liquid helium and cold-trapped atomic gases.
Electromagnetic Klein-Gordon and Dirac Equations in Scale Relativity
NASA Astrophysics Data System (ADS)
Célérier, Marie-Noëlle; Nottale, Laurent
We present a new step in the foundation of quantum field theory with the tools of scale relativity. Previously, quantum motion equations (Schrödinger, Klein-Gordon, Dirac, Pauli) have been derived as geodesic equations written with a quantum-covariant derivative operator. Then, the nature of gauge transformations, of gauge fields and of conserved charges have been given a geometric meaning in terms of a scale-covariant derivative tool. Finally, the electromagnetic Klein-Gordon equation has been recovered with a covariant derivative constructed by combining the quantum-covariant velocity operator and the scale-covariant derivative. We show here that if one tries to derive the electromagnetic Dirac equation from the Klein-Gordon one as for the free particle motion, i.e. as a square root of the time part of the Klein-Gordon operator, one obtains an additional term which is the relativistic analog of the spin-magnetic field coupling term of the Pauli equation. However, if one first applies the quantum covariance, then implements the scale covariance through the scale-covariant derivative, one obtains the electromagnetic Dirac equation in its usual form. This method can also be applied successfully to the derivation of the electromagnetic Klein-Gordon equation. This suggests it rests on more profound roots of the theory, since it encompasses naturally the spin-charge coupling.
Quadratic nonlinear Klein-Gordon equation in one dimension
NASA Astrophysics Data System (ADS)
Hayashi, Nakao; Naumkin, Pavel I.
2012-10-01
We study the initial value problem for the quadratic nonlinear Klein-Gordon equation vtt + v - vxx = λv2, t ∈ R, x ∈ R, with initial conditions v(0, x) = v0(x), vt(0, x) = v1(x), x ∈ R, where v0 and v1 are real-valued functions, λ ∈ R. Using the method of normal forms of Shatah ["Normal forms and quadratic nonlinear Klein-Gordon equations," Commun. Pure Appl. Math. 38, 685-696 (1985)], we obtain a sharp asymptotic behavior of small solutions without the condition of a compact support on the initial data, which was assumed in the previous work of J.-M. Delort ["Existence globale et comportement asymptotique pour l'équation de Klein-Gordon quasi-linéaire á données petites en dimension 1," Ann. Sci. Ec. Normale Super. 34(4), 1-61 (2001)].
Generalized Klein-Kramers equation: solution and application
NASA Astrophysics Data System (ADS)
Sau Fa, Kwok; Wang, K. G.
2013-09-01
A generalized Klein-Kramers equation based on the continuous time random walk model is investigated. The equation generalizes the ordinary and fractional Klein-Kramers equations. Analytic solutions for the probability density and first two moments (for the force-free case) are obtained, and their dynamic behaviors are investigated in detail. The model is used to describe the cell migration of two migrating transformed renal epithelial Madin-Darby canine kidney (MDCK-F) cell strains: wild-type (NHE+) and NHE-deficient (NHE-) cells. Our theoretical predictions are in good agreement with experimental work in the paper (Dieterich et al 2008 Proc. Nat. Acad. Sci. USA 105 459).
Dissociating Word Frequency and Age of Acquisition: The Klein Effect Revived (and Reversed)
ERIC Educational Resources Information Center
Dewhurst, Stephen A.; Barry, Christopher
2006-01-01
The Klein effect (G. S. Klein, 1964) refers to the finding that high-frequency words produce greater interference in a color-naming task than low-frequency words. The present study used the Klein effect to investigate the relationship between frequency and age of acquisition (AoA) by measuring their influence on color naming. Two experiments…
Embracing "All But My Life" by Gerda Weissmann Klein.
ERIC Educational Resources Information Center
Foster, Harold M.
1997-01-01
Discusses Gerda Weissmann Klein's book, "All But My Life," which chronicles the author's journey from a normal young (Jewish) woman to a slave in Nazi labor camps for six years. Argues that the book is well written, has characters of depth and complexity, affirms life through the ordeal of the Holocaust, and is a popular book with students. (SR)
Classification of integrable discrete Klein-Gordon models
NASA Astrophysics Data System (ADS)
Habibullin, Ismagil T.; Gudkova, Elena V.
2011-04-01
The Lie algebraic integrability test is applied to the problem of classification of integrable Klein-Gordon-type equations on quad graphs. The list of equations passing the test is presented, containing several well-known integrable models. A new integrable example is found; its higher symmetry is presented.
ERIC Educational Resources Information Center
Tucker, Lauren R.
1998-01-01
Deconstructs the "kiddie porn" media frame used by the industry and mainstream media to characterize Klein's ad campaign. Extends scholarship on the construction of youth in the media, showing how the kiddie-porn frame produces and reproduces common-sense beliefs about the nature of youth. Suggests a metadiscourse encompassing the politicized…
A Klein-tunneling transistor with ballistic graphene
NASA Astrophysics Data System (ADS)
Wilmart, Quentin; Berrada, Salim; Torrin, David; Nguyen, V. Hung; Fève, Gwendal; Berroir, Jean-Marc; Dollfus, Philippe; Plaçais, Bernard
2014-06-01
Today, the availability of high mobility graphene up to room temperature makes ballistic transport in nanodevices achievable. In particular, p-n-p transistors in the ballistic regime give access to Klein tunneling physics and allow the realization of devices exploiting the optics-like behavior of Dirac Fermions (DFs) as in the Veselago lens or the Fabry-Pérot cavity. Here we propose a Klein tunneling transistor based on the geometrical optics of DFs. We consider the case of a prismatic active region delimited by a triangular gate, where total internal reflection may occur, which leads to the tunable suppression of transistor transmission. We calculate the transmission and the current by means of scattering theory and the finite bias properties using non-equilibrium Green's function (NEGF) simulation.
Large Lepton Mixing in A String Brane World
NASA Astrophysics Data System (ADS)
Yanagida, T.
2004-12-01
It is very interesting if the observed disparity between mixing angles for neutrinos and for quarks has a geometrical origin in an extra dimensional space. We construct such an example in the type IIB string theory, where wave functions of left-handed leptons spread in an effective two dimensional extra space while wave finctions of left-handed quarks are localized at separate fixed points. This leads to the anarchy hypothesis for the left-handed leptons which explains naturally the large mixing angles for neutrinos. We emphasize, however, that this is only a projection of the six dimensional extra space onto a specific two dimensions. We have, in fact, another projected two dimensional extra space where the wave functions of left-handed quarks spread there and those of left-handed leptons are localized at fixed points.
Gravity and antigravity in a brane world with metastable gravitons
NASA Astrophysics Data System (ADS)
Gregory, R.; Rubakov, V. A.; Sibiryakov, S. M.
2000-09-01
In the framework of a five-dimensional three-brane model with quasi-localized gravitons we evaluate metric perturbations induced on the positive tension brane by matter residing thereon. We find that at intermediate distances, the effective four-dimensional theory coincides, up to small corrections, with General Relativity. This is in accord with Csaki, Erlich and Hollowood and in contrast to Dvali, Gabadadze and Porrati. We show, however, that at ultra-large distances this effective four-dimensional theory becomes dramatically different: conventional tensor gravity changes into scalar anti-gravity.
Graviton production in brane worlds by the dynamical Casimir effect
Durrer, Ruth; Ruser, Marcus; Vonlanthen, Marc; Wittwer, Peter
2009-05-01
If our Universe is a 3+1 brane in a warped 4+1 dimensional bulk so that its expansion can be understood as the motion of the brane in the bulk, the time dependence of the boundary conditions for arbitrary bulk fields can lead to particle creation via the dynamical Casimir effect. In this talk I report results for the simplest such scenario, when the only particle in the bulk is the graviton and the bulk is the 5 dimensional anti-de Sitter spacetime.
Three-family supersymmetric standardlike models from intersecting brane worlds.
Cvetic, M; Shiu, G; Uranga, A M
2001-11-12
We construct the first three family N = 1 supersymmetric string model with standard model gauge group SU(3)(C) x SU(2)(L) x U(1)(Y) from an orientifold of type IIA theory on T(6)/(Z(2) x Z(2)) and D6-branes intersecting at angles. In addition to the minimal supersymmetric standard model particles, the model contains right-handed neutrinos, a chiral (but anomaly-free) set of exotic multiplets, and extra vectorlike multiplets. We discuss some phenomenological features of this model. PMID:11690462
Cosmic microwave background radiation anisotropies in brane worlds.
Koyama, Kazuya
2003-11-28
We propose a new formulation to calculate the cosmic microwave background (CMB) spectrum in the Randall-Sundrum two-brane model based on recent progress in solving the bulk geometry using a low energy approximation. The evolution of the anisotropic stress imprinted on the brane by the 5D Weyl tensor is calculated. An impact of the dark radiation perturbation on the CMB spectrum is investigated in a simple model assuming an initially scale-invariant adiabatic perturbation. The dark radiation perturbation induces isocurvature perturbations, but the resultant spectrum can be quite different from the prediction of simple mixtures of adiabatic and isocurvature perturbations due to Weyl anisotropic stress. PMID:14683226
Aguayo, Joseph
2002-10-01
The author investigates the clinical affinity between Klein and Winnicott (1935-46) asa way to historically situate Winnicott 's later criticism of Klein's 'temperamental' inability to understand the impact of the environment on the infant's development. By setting out Klein s theories at the time when Winnicott began supervision with her in 1935, a context is established for the analysis of an unpublished 1937 manuscript by Klein ('Notes on baby'). The author argues that this direct and extensive infant observation demonstrates Klein's sensitivity to the familial environment. While Winnicott as a paediatrician showed enthusiasm for Klein s ideas, he also demonstrated a difference of opinion in emphasising the maternal environment of provision after his wartime evacuation experiences with London children. The factors leading to their mutual distancing are outlined as follows: (1) the post-Controversial Discussion atmosphere of the British Psycho-Analytical Society in 1944. The new non-aligned psychoanalytic 'middle group' allowed Winnicott to take a pick and choose attitude towards available analytic theories; (2) Winnicott us new clinical practices and theory differed from Klein 's, leading to a widening gap between 1946 and 1951. Winnicott's new theory and practice simultaneously represented his technical marginalisation of Klein s emphasis on the direct analysis of the patient s destructiveness by the time he delivered the 'Transitional objects' paper in 1951. PMID:12430543
MSSM from F-theory SU(5) with Klein monodromy
NASA Astrophysics Data System (ADS)
Crispim Romão, Miguel; Karozas, Athanasios; King, Stephen F.; Leontaris, George K.; Meadowcroft, Andrew K.
2016-06-01
We revisit a class of S U (5 ) supersymmetric grand unified theory (SUSY GUT) models which arise in the context of the spectral cover with Klein Group monodromy V4=Z2×Z2. We examine the polynomials of the corresponding factorized spectral cover and discuss the constraints imposed on their coefficients for the transitive and nontransitive realization of this monodromy. We show that Z2 matter parities can be realized via new geometric symmetries respected by the spectral cover.
Resolution of the Klein Paradox within Relativistic Quantum Mechanics
Alhaidari, A. D.
2011-10-27
We present a resolution of the Klein paradox within the framework of one-particle relativistic quantum mechanics (no pair production). Not only reflection becomes total but the vacuum remains neutral as well. This is accomplished by replacing the pair production process with virtual negative energy ''incidence'' within the barrier in a process analogous to the introduction of image charges in electrostatic and virtual sources in optics.
Klein paradox with spin-resolved electrons and positrons
Krekora, P.; Su, Q.; Grobe, R.
2005-12-15
Using numerical solutions to relativistic quantum field theory with space-time resolution, we illustrate how an incoming electron wave packet with a definite spin scatters off a supercritical potential step. We show that the production rate is reduced of only those electrons that have the same spin as the incoming electron is reduced. This spin-resolved result further clarifies the importance of the Pauli-exclusion principle for the Klein paradox.
Klein's theorem and the proof of E0 = mc2
NASA Astrophysics Data System (ADS)
Ohanian, Hans C.
2012-12-01
Despite repeated attempts, Einstein failed to give us a general and rigorous proof of his E0=mc2 relation. A completely general proof emerged in 1918 from a theorem on the four-vector character of energy-momentum of extended systems by the mathematician Felix Klein, but this proof is not well known, rarely seen in textbooks, and sometimes misunderstood. A simple version of this proof is presented here, with discussion of the crucial role of the energy-momentum tensor.
Fractional Klein-Gordon Equations and Related Stochastic Processes
NASA Astrophysics Data System (ADS)
Garra, Roberto; Orsingher, Enzo; Polito, Federico
2014-03-01
This paper presents finite-velocity random motions driven by fractional Klein-Gordon equations of order α in (0,1] . A key tool in the analysis is played by the McBride's theory which converts fractional hyper-Bessel operators into Erdélyi-Kober integral operators. Special attention is payed to the fractional telegraph process whose space-dependent distribution solves a non-homogeneous fractional Klein-Gordon equation. The distribution of the fractional telegraph process for α = 1 coincides with that of the classical telegraph process and its driving equation converts into the homogeneous Klein-Gordon equation. Fractional planar random motions at finite velocity are also investigated, the corresponding distributions obtained as well as the explicit form of the governing equations. Fractionality is reflected into the underlying random motion because in each time interval a binomial number of deviations B(n,α ) (with uniformly-distributed orientation) are considered. The parameter n of B(n,α ) is itself a random variable with fractional Poisson distribution, so that fractionality acts as a subsampling of the changes of direction. Finally the behaviour of each coordinate of the planar motion is examined and the corresponding densities obtained. Extensions to N -dimensional fractional random flights are envisaged as well as the fractional counterpart of the Euler-Poisson-Darboux equation to which our theory applies.
The potential for very high-frequency gravitational wave detection
NASA Astrophysics Data System (ADS)
Cruise, A. M.
2012-05-01
The science case for observing gravitational waves at frequencies in the millihertz-kilohertz range using LIGO, VIRGO, GEO600 or LISA is very strong and the first results are expected at these frequencies. However, as gravitational wave astronomy progresses beyond the first detections, other frequency bands may be worth exploring. Early predictions of gravitational wave emission from discrete sources at very much higher frequencies (megahertz and above) have been published and more recent studies of cosmological signals from inflation, Kaluza-Klein modes from gravitational interactions in brane worlds and plasma instabilities surrounding violent astrophysical events, are all possible sources. This communication examines current observational possibilities and the detector technology required to make meaningful observations at these frequencies.
Klein tunneling and Dirac potentials in trapped ions
Casanova, J.; Garcia-Ripoll, J. J.; Gerritsma, R.; Roos, C. F.; Solano, E.
2010-08-15
We propose the quantum simulation of the Dirac equation with potentials, allowing the study of relativistic scattering and Klein tunneling. This quantum relativistic effect permits a positive-energy Dirac particle to propagate through a repulsive potential via the population transfer to negative-energy components. We show how to engineer scalar, pseudoscalar, and other potentials in the 1+1 Dirac equation by manipulating two trapped ions. The Dirac spinor is represented by the internal states of one ion, while its position and momentum are described by those of a collective motional mode. The second ion is used to build the desired potentials with high spatial resolution.
Extended Klein-Gordon action, gravity and nonrelativistic fluid
Hassaiene, Mokhtar
2006-03-15
We consider a scalar field action for which the Lagrangian density is a power of the massless Klein-Gordon Lagrangian. The coupling of gravity to this matter action is considered. In this case, we show the existence of nontrivial scalar field configurations with vanishing energy-momentum tensor on any static, spherically symmetric vacuum solutions of the Einstein equations. These configurations in spite of being coupled to gravity do not affect the curvature of space-time. The properties of this particular matter action are also analyzed. For a particular value of the exponent, the extended Klein-Gordon action is shown to exhibit a conformal invariance without requiring the introduction of a nonminimal coupling. We also establish a correspondence between this action and a nonrelativistic isentropic fluid in one fewer dimension. This fluid can be identified with the (generalized) Chaplygin gas for a particular value of the power. It is also shown that the nonrelativistic fluid admits, apart from the Galileo symmetry, an additional symmetry whose action is a rescaling of the time.
Numerical computation of travelling breathers in Klein Gordon chains
NASA Astrophysics Data System (ADS)
Sire, Yannick; James, Guillaume
2005-05-01
We numerically study the existence of travelling breathers in Klein-Gordon chains, which consist of one-dimensional networks of nonlinear oscillators in an anharmonic on-site potential, linearly coupled to their nearest neighbors. Travelling breathers are spatially localized solutions having the property of being exactly translated by p sites along the chain after a fixed propagation time T (these solutions generalize the concept of solitary waves for which p=1). In the case of even on-site potentials, the existence of small amplitude travelling breathers superposed on a small oscillatory tail has been proved recently [G. James, Y. Sire, Travelling breathers with exponentially small tails in a chain of nonlinear oscillators, Commun. Math. Phys., 2005, in press (available online at http://www.springerlink.com)], the tail being exponentially small with respect to the central oscillation size. In this paper, we compute these solutions numerically and continue them into the large amplitude regime for different types of even potentials. We find that Klein-Gordon chains can support highly localized travelling breather solutions superposed on an oscillatory tail. We provide examples where the tail can be made very small and is difficult to detect at the scale of central oscillations. In addition, we numerically observe the existence of these solutions in the case of non-even potentials.
Dissipative effects in nonlinear Klein-Gordon dynamics
NASA Astrophysics Data System (ADS)
Plastino, A. R.; Tsallis, C.
2016-03-01
We consider dissipation in a recently proposed nonlinear Klein-Gordon dynamics that admits exact time-dependent solutions of the power-law form e_qi(kx-wt) , involving the q-exponential function naturally arising within the nonextensive thermostatistics (e_qz \\equiv [1+(1-q)z]1/(1-q) , with e_1^z=ez ). These basic solutions behave like free particles, complying, for all values of q, with the de Broglie-Einstein relations p=\\hbar k , E=\\hbar ω and satisfying a dispersion law corresponding to the relativistic energy-momentum relation E2 = c^2p2 + m^2c4 . The dissipative effects explored here are described by an evolution equation that can be regarded as a nonlinear generalization of the celebrated telegraph equation, unifying within one single theoretical framework the nonlinear Klein-Gordon equation, a nonlinear Schrödinger equation, and the power-law diffusion (porous-media) equation. The associated dynamics exhibits physically appealing traveling solutions of the q-plane wave form with a complex frequency ω and a q-Gaussian square modulus profile.
Little, Reginald B; McClary, Felicia; Rice, Bria; Jackman, Corine; Mitchell, James W
2012-12-14
The recent observation of the explosive oxidation of graphene with enhancement for decreasing temperature and the requirements for synchronizing oxidants for collective oxidation-reduction (redox) reactions presented a chemical scenario for the thermal harvesting by the magnetic spin Hall Effect. More experimental data are presented to demonstrate such spin Hall Effect by determining the influence of spins of so-called spectator fermionic cations. Furthermore, the so-called spectator bosonic cations are discovered to cause a Klein tunneling effect during the redox reaction of graphene. The Na(+) and K(+), fermionic cations and the Mg(2+) and Ca(2+), bosonic cations were observed and compared under a variety of experimental conditions: adiabatic reactions with initial temperatures (18-22 °C); reactions toward infinite dilution; isothermal reactions under nonadiabatic conditions at low temperature of 18 °C; reactions under paramagnetic O(2) or diamagnetic N(2) atmospheres of different permeabilities; reactions in applied and no applied external magnetic field; and reactions toward excess concentrations of common and uncommon Na(+) and Mg(2+) cations. The observed reaction kinetics and dynamics under these various, diverse conditions are consistent with the spin Hall mechanism, energy harvesting and short time violation of Second Law of Thermodynamics for redox reactions of graphene by the Na(+)K(+) mixture and are consistent with the Klein tunnel mechanism for the redox reactions of graphene by the Mg(2+)Ca(2+) mixture. Mixed spin Hall and Klein tunnel mechanisms are discovered to slow and modulate explosive redox reactions. Such spin Hall Effect also gives explanation of recent tunneling of electrons through boron nitride. PMID:23108034
Quantum Simulation of the Klein Paradox with Trapped Ions
Gerritsma, R.; Lanyon, B. P.; Kirchmair, G.; Zaehringer, F.; Hempel, C.; Blatt, R.; Roos, C. F.; Casanova, J.; Garcia-Ripoll, J. J.; Solano, E.
2011-02-11
We report on quantum simulations of relativistic scattering dynamics using trapped ions. The simulated state of a scattering particle is encoded in both the electronic and vibrational state of an ion, representing the discrete and continuous components of relativistic wave functions. Multiple laser fields and an auxiliary ion simulate the dynamics generated by the Dirac equation in the presence of a scattering potential. Measurement and reconstruction of the particle wave packet enables a frame-by-frame visualization of the scattering processes. By precisely engineering a range of external potentials we are able to simulate text book relativistic scattering experiments and study Klein tunneling in an analogue quantum simulator. We describe extensions to solve problems that are beyond current classical computing capabilities.
Emergence of Compact Structures in a Klein-Gordon Model
Rosenau, Philip; Kashdan, Eugene
2010-01-22
The Klein-Gordon model (KG) squarephi=P{sup '}(|phi|)(phi/|phi|) is Lorenz invariant and has a finite wave speed, yet its localized modes, whether Q balls or vortices, suffer from the same fundamental flaw as all other solitons--they extend indefinitely. Using the KG model as a case study, we demonstrate that appending the site potential, P{sub a}(|phi|), with a subquadratic part P(|{phi}|)=b{sup 2}|{phi}|{sup 1+{delta}}+P{sub a}(|{phi}|), 0<={delta}<1, induces particlelike modes with strictly compact support. These modes are robust and shorten in the direction of motion. Their interactions, which occur only on contact, are studied in two and three dimensions and are shown to span the whole range from being nearly elastic to plastic.
Quantum simulation of the Klein paradox with trapped ions.
Gerritsma, R; Lanyon, B P; Kirchmair, G; Zähringer, F; Hempel, C; Casanova, J; García-Ripoll, J J; Solano, E; Blatt, R; Roos, C F
2011-02-11
We report on quantum simulations of relativistic scattering dynamics using trapped ions. The simulated state of a scattering particle is encoded in both the electronic and vibrational state of an ion, representing the discrete and continuous components of relativistic wave functions. Multiple laser fields and an auxiliary ion simulate the dynamics generated by the Dirac equation in the presence of a scattering potential. Measurement and reconstruction of the particle wave packet enables a frame-by-frame visualization of the scattering processes. By precisely engineering a range of external potentials we are able to simulate text book relativistic scattering experiments and study Klein tunneling in an analogue quantum simulator. We describe extensions to solve problems that are beyond current classical computing capabilities. PMID:21405450
Long-Term Cognitive Impairment in Kleine-Levin Syndrome
Uguccioni, Ginevra; Lavault, Sophie; Chaumereuil, Charlotte; Golmard, Jean-Louis; Gagnon, Jean-François; Arnulf, Isabelle
2016-01-01
Study Objectives: In Kleine-Levin syndrome (KLS), episodes of hypersomnia, cognitive, and behavioral disturbances alternate with asymptomatic periods. Because 50% of patients report decreased academic performances, we evaluated their cognitive status during asymptomatic periods, determinants of deficits, and changes during follow-up. Methods: The cognitive assessment during asymptomatic periods in all consecutive patients with typical KLS and healthy controls included the non-verbal intelligence quotient (Raven Progressive Matrices), the Trail Making Test, the Stroop Color-Word Test, the Wechsler Memory Test, verbal fluencies, the Free and Cued Learning Memory Test, and the Rey-Osterreith Complex Figure. Cognitive status was reevaluated after 0.5 to 2 y in 44 patients. Results: At baseline, compared with the 42 controls, the 122 patients with KLS exhibited lower non-verbal intelligence quotient, speed of processing, attention, and reduced retrieval strategies in episodic memory. Higher episode frequency, shorter episode duration, shorter time since last episode, deeper sleep, and megaphagia during episodes predicted impaired memory. The visuoconstructional abilities and non-verbal memory were intact. After a mean follow-up of 1.7 ± 1.0 y, the episode frequency decreased from 4.6 ± 4.8 to 1.7 ± 1.9/y. The logical reasoning and attention improved, the processing speed remained low, and the retrieval strategies in verbal memory further worsened. Conclusions: In this field study, one-third of patients with KLS have long-term cognitive deficits affecting retrieval and processing speed. Cognitive function should be systematically tested in patients with KLS, which appears important to help patients in their academic studies. Citation: Uguccioni G, Lavault S, Chaumereuil C, Golmard JL, Gagnon JF, Arnulf I. Long-term cognitive impairment in kleine-levin syndrome. SLEEP 2016;39(2):429–438. PMID:26414895
Spin-dependent Klein tunneling in polariton graphene with photonic spin-orbit interaction
NASA Astrophysics Data System (ADS)
Solnyshkov, Dmitry; Nalitov, Anton; Teklu, Berihu; Franck, Louis; Malpuech, Guillaume
2016-02-01
We study Klein tunneling in polariton graphene. We show that the photonic spin-orbit coupling associated with the energy splitting between TE and TM photonic modes can be described as an emergent gauge field. It suppresses the Klein tunneling in a small energy range close to the Dirac points. Thanks to polariton spin-anisotropic interactions, polarized optical pumping allows one to create potential barriers acting on a single polariton spin. We show that the resulting spin-dependent Klein tunneling can be used to create a perfectly transmitting polarization rotator operating at microscopic scale.
Spacetimes with a separable Klein-Gordon equation in higher dimensions
NASA Astrophysics Data System (ADS)
Kolář, Ivan; Krtouš, Pavel
2016-01-01
We study spacetimes that lead to a separable Klein-Gordon equation in a general number of dimensions. We introduce an ansatz for the metric in higher dimensions motivated by analogical work by Carter in four dimensions and find solutions of the Klein-Gordon equation. For such a metric we solve the Einstein equations and regain the Kerr-NUT-(A)dS spacetime as one of our results. Other solutions lead to the Einstein-Kähler metric of a Euclidean signature. Next we investigate a warped geometry of two Klein-Gordon separable spaces with a properly chosen warped factor. We show that the resulting metric leads also to a separable Klein-Gordon equation and we find the corresponding solutions. Finally, we solve the Einstein equations for the warped geometry and obtain new solutions.
["Is it an animal inside? "Melanie Klein's unpublished Don Juan Paper (1939)].
Frank, Claudia
2008-01-01
Klein had been asked to contribute an article to the birthday number of the International Journal for Jones. The author outlines how she hurriedly wrote a text about Don Juan which, however, was rejected by the editor. Essential parts of it are presented in German translation. The manuscript is discussed in the context of Klein's published work as well as of the relevant contemporary literature. In Klein's view, Don Juan's genitality is determined by oral impulses and fears. By his manic acting out he attempts to ward off a depressive break-down. The paper ends with some reflections about why Klein--ontrary to her intention--failed to revise her manuscript for later publication. PMID:19230330
Continuum percolation on nonorientable surfaces: the problem of permeable disks on a Klein bottle
NASA Astrophysics Data System (ADS)
Borman, V. D.; Grekhov, A. M.; Tronin, V. N.; Tronin, I. V.
2015-11-01
The percolation threshold and wrapping probability (R ∞) for the two-dimensional problem of continuum percolation on the surface of a Klein bottle have been calculated by the Monte Carlo method with the Newman-Ziff algorithm for completely permeable disks. It has been shown that the percolation threshold of disks on the Klein bottle coincides with the percolation threshold of disks on the surface of a torus, indicating that this threshold is topologically invariant. The scaling exponents determining corrections to the wrapping probability and critical concentration owing to the finite-size effects are also topologically invariant. At the same time, the quantities R ∞ are different for percolation on the torus and Klein bottle and are apparently determined by the topology of the surface. Furthermore, the difference between the R ∞ values for the torus and Klein bottle means that at least one of the percolation clusters is degenerate.
Lie group symmetries and Riemann function of Klein-Gordon-Fock equation with central symmetry
NASA Astrophysics Data System (ADS)
Kochetov, Bogdan A.
2014-06-01
In the present paper Lie symmetry group method is applied to find new exact invariant solutions for Klein-Gordon-Fock equation with central symmetry. The found invariant solutions are important for testing finite-difference computational schemes of various boundary value problems of Klein-Gordon-Fock equation with central symmetry. The classical admitted symmetries of the equation are found. The infinitesimal symmetries of the equation are used to find the Riemann function constructively.
Reduced thalamic and pontine connectivity in kleine-levin syndrome.
Engström, Maria; Karlsson, Thomas; Landtblom, Anne-Marie
2014-01-01
The Kleine-Levin syndrome (KLS) is a rare sleep disorder, characterized by exceptionally long sleep episodes. The neuropathology of the syndrome is unknown and treatment is often inadequate. The aim of the study was to improve understanding of the underlying neuropathology, related to cerebral networks, in KLS during sleep episodes. One patient with KLS and congenital nystagmus was investigated by resting state functional magnetic resonance imaging during both asymptomatic and hypersomnic periods. Fourteen healthy subjects were also investigated as control samples. Functional connectivity was assessed from seed regions of interest in the thalamus and the dorsal pons. Thalamic connectivity was normal in the asymptomatic patient whereas the connectivity between the brain stem, including dorsal pons, and the thalamus was diminished during hypersomnia. These results suggest that the patient's nystagmus and hypersomnia might have their pathological origin in adjacent dorsal pontine regions. This finding provides additional knowledge of the cerebral networks involved in the neuropathology of this disabling disorder. Furthermore, these findings regarding a rare syndrome have broad implications, and results could be of interest to researchers and clinicians in the whole field of sleep medicine. PMID:24765085
Klein tunneling and supercollimation of pseudospin-1 electromagnetic waves
NASA Astrophysics Data System (ADS)
Fang, A.; Zhang, Z. Q.; Louie, Steven G.; Chan, C. T.
2016-01-01
Pseudospin plays a central role in many novel physical properties of graphene and other artificial systems which have pseudospins of 1 /2 . Here we show that in certain photonic crystals (PCs) exhibiting conical dispersions at k =0 , the eigenmodes near the "Dirac-like point" can be described by an effective spin-orbit Hamiltonian with a higher dimension value S =1 , treating the wave propagation in positive index (upper cone), negative index (lower cone), and zero index (flat band) media within a unified framework. The three-component spinor gives rise to boundary conditions distinct from those of pseudospin 1 /2 , leading to wave transport behaviors as manifested in super Klein tunneling and supercollimation. For example, collimation can be realized more easily with pseudospin 1 than pseudospin 1 /2 . The effective medium description of the PCs allows us to further understand the physics of pseudospin-1 electromagnetic (EM) waves from the perspective of complementary materials. The special wave scattering properties of pseudospin-1 EM waves, in conjunction with the discovery that the effective photonic potential can be varied by a simple change of length scale, offer ways to control photon transport. As a useful platform to study pseudospin-1 physics, dielectric PCs are much easier to fabricate and characterize than ultracold atom systems proposed previously. The system also provides a platform to realize the concept of "complementary medium" using dielectric materials and has the unique advantage of low loss.
Rocamora, Rodrigo; Gil-Nagel, Antonio; Franch, Oriol; Vela-Bueno, Antonio
2010-11-01
Kleine-Levin syndrome and menstrual-related hypersomnia are rare idiopathic sleep disorders occurring primarily in adolescence. They are characterized by intermittent periods of excessive sleepiness, cognitive disturbances, and behavioral abnormalities. In both, the etiology remains unknown but autoinmune, hormonal, infectious, and inflammatory mechanisms have been proposed. The authors describe, for the first time, the association of Kleine-Levin syndrome and menstrual-related hypersomnia in 2 adolescent siblings who shared the human leukocyte antigen (HLA) loci DQB1*0501. The same haplotype has been associated with sleepwalking and with rapid eye movement (REM) sleep behavior disorder. This gender differences in the manifestation of a probably genetic influenced sleep disorder suggests that hormonal mechanisms could be implicated in the phenotypical expression of this sleep disorder. The male sibling with Kleine-Levin syndrome was easily controlled with carbamazepine in low doses, but his sister could be only efficaciously treated with oral contraceptives. PMID:20404354
NASA Astrophysics Data System (ADS)
Bao, Zhi-qiang; Shi, Jun-jie; Zhang, Min
2013-05-01
The electronic structure and magnetic characteristics of Klein graphene nanoribbons (KGNRs), as observed by Suenaga and Koshino [K. Suenaga and M. Koshino, Nature 468, 1088 (2010)], are investigated using first-principles calculations. We find three new characteristics induced by the Klein boundary. First, the localized edge states in the KGNRs have a ferromagnetic coupling rather than the antiferromagnetic coupling of the zigzag graphene nanoribbons (ZGNRs). Lieb's theorem is no longer applicable in the KGNRs. Second, the marginal single carbon adatom of the ZGNRs can destroy the edge states nearby. The edge states can recover if the length of the zigzag chains is equal to or greater than five times that of the lattice constant. Finally, we show that the pentagon-heptagon edge can be induced from the Klein boundary.
The Klein-Gordon equation of a rotating charged hairy black hole in (2 + 1) dimensions
NASA Astrophysics Data System (ADS)
Pourhassan, B.
2016-03-01
In this paper, we consider the Klein-Gordon equation in a 3D charged rotating hairy black hole background to study behavior of a massive scalar field. In the general case, we find periodic-like behavior for the scalar field which may vanish at the black hole horizon or far from the black hole horizon. For the special cases of non-rotating or near horizon approximation, we find radial solution of Klein-Gordon equation in terms of hypergeometric and Kummer functions. Also for the case of uncharged black hole, we find numerical solution of the Klein-Gordon equation as periodic function which may enhance out of the black hole or vanish at horizon. We find allowed boundary conditions which may yield to the identical bosons described by scalar field.
Wigner function for Klein-Gordon oscillator in commutative and noncommutative spaces
NASA Astrophysics Data System (ADS)
Hassanabadi, S.; Ghominejad, M.
2016-06-01
As a quasi-probability distribution function in phase-space and a special representation of the density matrix, the Wigner function is of great significance in physics. In this work, the Wigner function for the Klein-Gordon oscillator is studied in commutative and noncommutative spaces. We first study the Wigner function for Klein-Gordon oscillator in commutative space then, by using a generalized Bopp's shift method, we obtain the corresponding Wigner function in noncommutative space. The additional terms in Wigner function on a NC space is related to the noncommutativity of space.
A Note on Exact Travelling Wave Solutions for the Klein-Gordon- Zakharov Equations
NASA Astrophysics Data System (ADS)
Zhang, Zai-Yun; Zhang, Ying-Hui; Gan, Xiang-Yang; Yu, De-Ming
2012-04-01
In this paper, we investigate the travelling wave solutions for the Klein-Gordon-Zakharov equations by using the modified trigonometric function series method benefited to the ideas of Z. Y. Zhang, Y. X. Li, Z. H. Liu, and X. J. Miao, Commun. Nonlin. Sci. Numer. Simul. , 3097 (2011). Exact travelling wave solutions are obtained
On the radius of spatial analyticity for the 1d Dirac-Klein-Gordon equations
NASA Astrophysics Data System (ADS)
Selberg, Sigmund; Tesfahun, Achenef
2015-11-01
We study the well-posedness of the Dirac-Klein-Gordon system in one space dimension with initial data that have an analytic extension to a strip around the real axis. It is proved that the radius of analyticity σ (t) of the solutions at time t cannot decay faster than 1 /t4 as | t | → ∞.
What Do Klein et al. Tell Us about Test Scores in Texas?
ERIC Educational Resources Information Center
Toenjes, Laurence A.
2005-01-01
A paper appearing in this journal by Klein, Hamilton, McCaffrey and Stecher (2000) attempted to raise serious questions about the validity of the gains in student performance as measured by Texas' standardized test, the Texas Assessment of Academic Skills (TAAS). Part of their analysis was based on the results of three tests which they…
Scattering theory for the Klein-Gordon equation with nondecreasing potentials
Cruz, Maximino; Arredondo R, Juan H.
2008-11-15
The Klein-Gordon equation is considered in the case of nondecreasing potentials. The energy inner product is nonpositive on a subspace of infinite dimension, not consisting entirely of eigenvectors of the associated operator. A scattering theory for this case is developed and asymptotic completeness for generalized Moeller operators is proven.
All but Her Life: Holocaust Survivor Gerda Klein Shares with Learners
ERIC Educational Resources Information Center
Lincoln, Margaret
2007-01-01
During the 2006-2007 school year, students from Battle Creek, Michigan, high school joined numerous others from across the state in reading holocaust survivor Gerda Klein's memoir, "All But My Life." Published in 57 editions and still in print after 50 years, the book is the inspiring account of a remarkable individual who endured unspeakable…
The statistical properties of Klein-Gordon oscillator in noncommutative space
Hassanabadi, H. Hosseini, S. S.; Boumali, A.; Zarrinkamar, S.
2014-03-15
We study the relativistic spin-zero bosons influenced by the Klein-Gordon oscillator and an external magnetic field in noncommutative formulation. The problem is considered in two dimensions and is solved in an exact analytical manner. Having found the spectrum of the system, the statistical properties of an N-boson system are reported.
NASA Astrophysics Data System (ADS)
Onyeaju, M. C.; Ikot, A. N.; Chukwuocha, E. O.; Obong, H. P.; Zare, S.; Hassanabadi, H.
2016-06-01
Scattering and bound states solution for the one-dimensional Klein-Gordon particle with Hylleraas potential is presented within the frame work of position dependent effective mass formalism. We calculate in detail the reflection and transmission coefficients using the properties of hypergeometric functions and the equation of continuity of the wave functions.
Stability of Schwarzschild-AdS for the Spherically Symmetric Einstein-Klein-Gordon System
NASA Astrophysics Data System (ADS)
Holzegel, Gustav; Smulevici, Jacques
2013-01-01
In this paper, we study the global behavior of solutions to the spherically symmetric coupled Einstein-Klein-Gordon (EKG) system in the presence of a negative cosmological constant. For the Klein-Gordon mass-squared satisfying a ≥ -1 (the Breitenlohner-Freedman bound being a > -9/8), we prove that the Schwarzschild-AdS spacetimes are asymptotically stable: Small perturbations of Schwarzschild-AdS initial data again lead to regular black holes, with the metric on the black hole exterior approaching, at an exponential rate, a Schwarzschild-AdS spacetime. The main difficulties in the proof arise from the lack of monotonicity for the Hawking mass and the asymptotically AdS boundary conditions, which render even (part of) the orbital stability intricate. These issues are resolved in a bootstrap argument on the black hole exterior, with the redshift effect and weighted Hardy inequalities playing the fundamental role in the analysis. Both integrated decay and pointwise decay estimates are obtained. As a corollary of our estimates on the Klein-Gordon field, one obtains in particular exponential decay in time of spherically-symmetric solutions to the linear Klein-Gordon equation on Schwarzschild-AdS.
Potential magnetic properties of nanotubes ( n, 0) with Klein and Fujita edges
NASA Astrophysics Data System (ADS)
Luhavaya, H. M.; Pavlov, M. V.; Ermilov, A. Yu.; Stepanov, N. F.
2012-08-01
Analytical solutions for localized states of zigzag-type nanotube (NT) fragments with various combinations of Klein and Fujita borders are considered using the Hückel approach. It is shown that the equations for determining molecular orbitals (MOs) in systems with two Klein edges are similar to equations for systems with two Fujita edges. An analytical formula for the energies of all π MOs is obtained for systems that have a Klein edge on one side and a Fujita edge on the other. It is established that these systems have n orbitals with energy α that are localized on the Fujita and Klein edges in dependence on the MO symmetry. The degeneracy of edge orbitals indicates that there is a tendency toward single occupancy of them and to the appearance of spin (magnetic) properties. In addition, the energies of the states of different multiplicity for NT fragments (8, 0) are calculated using the CASSCF approach. It is shown that the ground state has a multiplicity of 9, as was also indicated by estimates obtained using the density functional method (B3LYP). It is concluded that zigzag-type NTs with asymmetric edges have a tendency to exhibit spin properties. It is noted that the construction of nanoscale magnetic materials based on them is very promising.
Verification of Compton Collision and Klein-Nishina Formulas--An Undergraduate Laboratory Experiment
ERIC Educational Resources Information Center
Singhal, R. P.; Burns, A. J.
1978-01-01
Describes an experiment to verify the Compton collision formula and the angular dependance of the Klein-Nishina formula. Equipment used is a 1-mCi(137)Cs source, 2x2 in. NaI detector and a multichannel analyzer. Suitable for honor undergraduates. (Author/GA)
NASA Astrophysics Data System (ADS)
Ghafourian, M.; Hassanabadi, H.
2016-06-01
The Shannon information entropies for the Klein-Gordon equations are evaluated for the Poschl-Teller potential, and the position-space information entropies for the ground and the excited states are calculated.
Orbital instability of standing waves for the quadratic-cubic Klein-Gordon-Schrödinger system
NASA Astrophysics Data System (ADS)
Natali, Fábio; Pastor, Ademir
2015-08-01
We consider the Klein-Gordon-Schrödinger system with quadratic and cubic interactions. Smooth curves of periodic- and solitary-wave solutions are obtained via the implicit function theorem. Orbital instability of such waves is then established.
Inhibiting Klein Tunneling in a Graphene p-n Junction without an External Magnetic Field.
Oh, Hyungju; Coh, Sinisa; Son, Young-Woo; Cohen, Marvin L
2016-07-01
We study by first-principles calculations a densely packed island of organic molecules (F_{4}TCNQ) adsorbed on graphene. We find that with electron doping the island naturally forms a p-n junction in the graphene sheet. For example, a doping level of ∼3×10^{13} electrons per cm^{2} results in a p-n junction with an 800 meV electrostatic potential barrier. Unlike in a conventional p-n junction in graphene, in the case of the junction formed by an adsorbed organic molecular island we expect that the Klein tunneling is inhibited, even without an applied external magnetic field. Here Klein tunneling is inhibited by the ferromagnetic order that spontaneously occurs in the molecular island upon doping. We estimate that the magnetic barrier in the graphene sheet is around 10 mT. PMID:27419583
Effects of parity-time symmetry in nonlinear Klein-Gordon models and their stationary kinks.
Demirkaya, A; Frantzeskakis, D J; Kevrekidis, P G; Saxena, A; Stefanov, A
2013-08-01
In this work, we introduce some basic principles of PT-symmetric Klein-Gordon nonlinear field theories. By formulating a particular antisymmetric gain and loss profile, we illustrate that the stationary states of the model do not change. However, the stability critically depends on the gain and loss profile. For a symmetrically placed solitary wave (in either the continuum model or a discrete analog of the nonlinear Klein-Gordon type), there is no effect on the steady state spectrum. However, for asymmetrically placed solutions, there exists a measurable effect of which a perturbative mathematical characterization is offered. It is generally found that asymmetry towards the lossy side leads towards stability, while towards the gain side produces instability. Furthermore, a host of finite size effects, which disappear in the infinite domain limit, are illustrated in connection to the continuous spectrum of the problem. PMID:24032958
Entanglement generation due to the Klein tunneling in a graphene sheet
NASA Astrophysics Data System (ADS)
Ghanbari-Adivi, E.; Soltani, M.; Sheikhali, M.
2016-06-01
Scattering of a ballistic electron by the quantum-dot spin qubits fixed in a graphene nanoribbon is investigated theoretically. Two simple cases are investigated in details: scattering from a static quantum dot and scattering from two static quantum dots located at a fixed distance from each other. For the first case, it is shown that the Klein tunneling in a graphene sheet leads to a final entangled state for the reflected and/or transmitted electrons. The amount of the generated entanglement through the scattering process is a function of the incident angle for the ballistic electrons. For the second case, it is shown that the created correlation between the quantum dots is a periodic function of their distance. For frontal incident electrons in both cases, there is not any reflection and the Klein tunneling effect leads to a final well-correlated state for the scattering system.
Nonlinear self-adjointness and conservation laws of Klein-Gordon-Fock equation with central symmetry
NASA Astrophysics Data System (ADS)
Abdulwahhab, Muhammad Alim
2015-05-01
The concept of nonlinear self-adjointness, introduced by Ibragimov, has significantly extends approaches to constructing conservation laws associated with symmetries since it incorporates the strict self-adjointness, the quasi self-adjointness as well as the usual linear self-adjointness. Using this concept, the nonlinear self-adjointness condition for the Klein-Gordon-Fock equation was established and subsequently used to construct simplified but infinitely many nontrivial and independent conserved vectors. The Noether's theorem was further applied to the Klein-Gordon-Fock equation to explore more distinct first integrals, result shows that conservation laws constructed through this approach are exactly the same as those obtained under strict self-adjointness of Ibragimov's method.
Klein tunneling of helical edge states in narrow strips of a two-dimensional topological insulator
NASA Astrophysics Data System (ADS)
Takagaki, Y.
2016-01-01
The quantum transmission of helical edge states across a square potential barrier is numerically investigated in narrow channels of a two-dimensional topological insulator. Although the transmission probability in general decreases when a potential offset is introduced in the middle of the channels, the transmission remains almost perfect regardless of the amplitude and length of the potential offset when the hybridization energy gap is closed by tuning the off-diagonal spin-orbit terms in the effective four-band Hamiltonian. The approximate absence of scattering resembling the Klein tunneling, where the transmission is unimpeded as an electron propagates relativistically as a hole in the barrier without decay, improves further when an interference condition is satisfied within the barrier. The dependence of the residual reflection on the Fermi level reveals anomalous characteristics in the Klein tunneling regime.
Suppressing Klein tunneling in graphene using a one-dimensional array of localized scatterers.
Walls, Jamie D; Hadad, Daniel
2015-01-01
Graphene's unique physical and chemical properties make it an attractive platform for use in micro- and nanoelectronic devices. However, electrostatically controlling the flow of electrons in graphene can be challenging as a result of Klein tunneling, where electrons normally incident to a one-dimensional potential barrier of height V are perfectly transmitted even as V → ∞. In this study, theoretical and numerical calculations predict that the transmission probability for an electron wave normally incident to a one-dimensional array of localized scatterers can be significantly less than unity when the electron wavelength is smaller than the spacing between scatterers. In effect, placing periodic openings throughout a potential barrier can, somewhat counterintuitively, decrease transmission in graphene. Our results suggest that electrostatic potentials with spatial variations on the order of the electron wavelength can suppress Klein tunneling and could find applications in developing graphene electronic devices. PMID:25678400
Inhibiting Klein Tunneling in a Graphene p -n Junction without an External Magnetic Field
NASA Astrophysics Data System (ADS)
Oh, Hyungju; Coh, Sinisa; Son, Young-Woo; Cohen, Marvin L.
2016-07-01
We study by first-principles calculations a densely packed island of organic molecules (F4TCNQ ) adsorbed on graphene. We find that with electron doping the island naturally forms a p -n junction in the graphene sheet. For example, a doping level of ˜3 ×1013 electrons per cm2 results in a p -n junction with an 800 meV electrostatic potential barrier. Unlike in a conventional p -n junction in graphene, in the case of the junction formed by an adsorbed organic molecular island we expect that the Klein tunneling is inhibited, even without an applied external magnetic field. Here Klein tunneling is inhibited by the ferromagnetic order that spontaneously occurs in the molecular island upon doping. We estimate that the magnetic barrier in the graphene sheet is around 10 mT.
Suppressing Klein tunneling in graphene using a one-dimensional array of localized scatterers
Walls, Jamie D.; Hadad, Daniel
2015-01-01
Graphene's unique physical and chemical properties make it an attractive platform for use in micro- and nanoelectronic devices. However, electrostatically controlling the flow of electrons in graphene can be challenging as a result of Klein tunneling, where electrons normally incident to a one-dimensional potential barrier of height V are perfectly transmitted even as V → ∞. In this study, theoretical and numerical calculations predict that the transmission probability for an electron wave normally incident to a one-dimensional array of localized scatterers can be significantly less than unity when the electron wavelength is smaller than the spacing between scatterers. In effect, placing periodic openings throughout a potential barrier can, somewhat counterintuitively, decrease transmission in graphene. Our results suggest that electrostatic potentials with spatial variations on the order of the electron wavelength can suppress Klein tunneling and could find applications in developing graphene electronic devices. PMID:25678400
Gadoth, N; Dickerman, Z; Bechar, M; Laron, Z; Lavie, P
1987-01-01
"Acute" hypothalamic-pituitary function tests including insulin tolerance test, LRH, ACTH and TRH stimulation tests and nocturnal secretory pattern of human growth hormone, 11-OHCS, prolactin, FSH, LH and TSH were studied in a 23-year-old male with Kleine-Levin syndrome during the course of a typical hypersomnic attack. The "acute" tests revealed paradoxical growth-hormone response to TRH stimulation, borderline high basal plasma prolactin levels with normal response to TRH. The hormonal secretory pattern during sleep revealed abnormalities in LH, 11-OHCS and prolactin secretion. These together with the results of the "acute" tests are indicative of an abnormality in the hypothalamic regulation of various pituitary hormones. This observation may indeed be the first laboratory demonstration confirming a long-standing hypothesis that Kleine-Levin syndrome is related to hypothalamic dysfunction. PMID:3477962
Kovalyov, Mikhail
2010-06-15
In this article the sets of solutions of the sine-Gordon equation and its linearization the Klein-Gordon equation are discussed and compared. It is shown that the set of solutions of the sine-Gordon equation possesses a richer structure which partly disappears during linearization. Just like the solutions of the Klein-Gordon equation satisfy the linear superposition principle, the solutions of the sine-Gordon equation satisfy a nonlinear superposition principle.
NASA Astrophysics Data System (ADS)
Donker, H. C.; Katsnelson, M. I.; De Raedt, H.; Michielsen, K.
2016-09-01
The logical inference approach to quantum theory, proposed earlier De Raedt et al. (2014), is considered in a relativistic setting. It is shown that the Klein-Gordon equation for a massive, charged, and spinless particle derives from the combination of the requirements that the space-time data collected by probing the particle is obtained from the most robust experiment and that on average, the classical relativistic equation of motion of a particle holds.
Mie scattering analog in graphene: Lensing, particle confinement, and depletion of Klein tunneling
NASA Astrophysics Data System (ADS)
Heinisch, R. L.; Bronold, F. X.; Fehske, H.
2013-04-01
Guided by the analogy to Mie scattering of light on small particles, we show that the propagation of a Dirac-electron wave in graphene can be manipulated by a circular gated region acting as a quantum dot. Large dots enable electron lensing, while for smaller dots resonant scattering entails electron confinement in quasibound states. Forward scattering and Klein tunneling can be almost switched off for small dots by a Fano resonance arising from the interference between resonant scattering and the background partition.
Klein-Gordon equations for energy-momentum of the relativistic particle in rapidity space
Yamaleev, R. M.
2013-10-15
The notion of four-rapidity is defined as a four-vector with one time-like and three space-like coordinates. It is proved, the energy and momentum defined in the space of four-rapidity obey Klein-Gordon equations constrained by the classical trajectory of a relativistic particle. It is shown, for small values of a proper mass influence of the constraint is weakened and the classical motion gains features of a wave motion.
Deep-water sponges (Porifera) from Bonaire and Klein Curaçao, Southern Caribbean.
Van Soest, Rob W M; Meesters, Erik H W G; Becking, Leontine E
2014-01-01
Four submersible dives off the coast of Bonaire (Caribbean Netherlands) and Klein Curaçao (Curaçao) to depths of 99.5-242 m, covering lower mesophotic and upper dysphotic zones, yielded 52 sponge specimens belonging to 31 species. Among these we identified 13 species as new to science. These are Plakinastrella stinapa n. sp., Pachastrella pacoi n. sp., Characella pachastrelloides n. sp., Geodia curacaoensis n. sp., Caminus carmabi n. sp., Discodermia adhaerens n. sp., Clathria (Microciona) acarnoides n. sp., Antho (Acarnia) pellita n. sp., Parahigginsia strongylifera n. sp., Calyx magnoculata n. sp., Neopetrosia dutchi n. sp., Neopetrosia ovata n. sp. and Neopetrosia eurystomata n. sp. We also report an euretid hexactinellid, which belongs to the rare genus Verrucocoeloidea, recently described (2014) as V. liberatorii Reiswig & Dohrmann. The remaining 18 already known species are all illustrated by photos of the habit, either in situ or 'on deck', but only briefly characterized in an annotated table to confirm their occurrence in the Southern Caribbean. The habitat investigated-steep limestone rocks, likely representing Pleistocene fossil reefs--is similar to deep-water fossil reefs at Barbados of which the sponges were sampled and studied by Van Soest and Stentoft (1988). A comparison is made between the two localities, showing a high degree of similarity in sponge composition: 53% of the present Bonaire-Klein Curaçao species were also retrieved at Barbados. At the level of higher taxa (genera, families) Bonaire-Klein Curaçao shared approximately 80% of its lower mesophotic and upper dysphotic sponge fauna with Barbados, despite a distance between them of 1000 km, indicating high faunal homogeneity. We also preliminarily compared the shallow-water (euphotic) sponge fauna of Curaçao with the combined data available for the Barbados, Bonaire and Klein Curaçao mesophotic and upper dysphotic sponges, which resulted in the conclusion that the two faunas show only
Sharpening the weak gravity conjecture with dimensional reduction
NASA Astrophysics Data System (ADS)
Heidenreich, Ben; Reece, Matthew; Rudelius, Tom
2016-02-01
We investigate the behavior of the Weak Gravity Conjecture (WGC) under toroidal compactification and RG flows, finding evidence that WGC bounds for single photons become weaker in the infrared. By contrast, we find that a photon satisfying the WGC will not necessarily satisfy it after toroidal compactification when black holes charged under the Kaluza-Klein photons are considered. Doing so either requires an infinite number of states of different charges to satisfy the WGC in the original theory or a restriction on allowed compactification radii. These subtleties suggest that if the Weak Gravity Conjecture is true, we must seek a stronger form of the conjecture that is robust under compactification. We propose a "Lattice Weak Gravity Conjecture" that meets this requirement: a superextremal particle should exist for every charge in the charge lattice. The perturbative heterotic string satisfies this conjecture. We also use compactification to explore the extent to which the WGC applies to axions. We argue that gravitational instanton solutions in theories of axions coupled to dilaton-like fields are analogous to extremal black holes, motivating a WGC for axions. This is further supported by a match between the instanton action and that of wrapped black branes in a higher-dimensional UV completion.
The Einstein-Klein-Gordon Equations, Wave Dark Matter, and the Tully-Fisher Relation
NASA Astrophysics Data System (ADS)
Goetz, Andrew S.
2015-01-01
We examine the Einstein equation coupled to the Klein-Gordon equation for a complex-valued scalar field. These two equations together are known as the Einstein-Klein-Gordon system. In the low-field, non-relativistic limit, the Einstein-Klein-Gordon system reduces to the Poisson-Schrodinger system. We describe the simplest solutions of these systems in spherical symmetry, the spherically symmetric static states, and some scaling properties they obey. We also describe some approximate analytic solutions for these states. The EKG system underlies a theory of wave dark matter, also known as scalar field dark matter (SFDM), boson star dark matter, and Bose-Einstein condensate (BEC) dark matter. We discuss a possible connection between the theory of wave dark matter and the baryonic Tully-Fisher relation, which is a scaling relation observed to hold for disk galaxies in the universe across many decades in mass. We show how fixing boundary conditions at the edge of the spherically symmetric static states implies Tully-Fisher-like relations for the states. We also catalog other ``scaling conditions'' one can impose on the static states and show that they do not lead to Tully-Fisher-like relations--barring one exception which is already known and which has nothing to do with the specifics of wave dark matter.
Wave operators to a quadratic nonlinear Klein-Gordon equation in two space dimensions revisited
NASA Astrophysics Data System (ADS)
Hayashi, Nakao; Naumkin, Pavel I.; Tonegawa, Satoshi
2012-08-01
We continue to study the existence of the wave operators for the nonlinear Klein-Gordon equation with quadratic nonlinearity in two space dimensions {(partialt2-Δ+m2) u=λ u2,( t,x) in{R}×{R}2}. We prove that if u1+in{H}^{3/2+3γ,1}( {R}2),{ }u2+in{H}^{1/2+3γ,1}( {R} 2), where {γin( 0,1/4)} and the norm {Vert u1+Vert_{{H}1^{3/2+γ}}+Vert u2+Vert_{{H}1^{1/2+γ}}≤ρ,} then there exist ρ > 0 and T > 1 such that the nonlinear Klein-Gordon equation has a unique global solution {uin{C}( [ T,infty) ;{H}^{1/2}( {R}2) ) } satisfying the asymptotics Vert u( t) -u0 ( t) Vert _{{H}^{1/2}} ≤ Ct^{-1/2-γ} for all t > T, where u 0 denotes the solution of the free Klein-Gordon equation.
Chacko, Z.; Graesser, M.L.; Grojean, C.; Pilo, L.
2003-12-11
At present no theory of a massive graviton is known that is consistent with experiments at both long and short distances. The problem is that consistency with long distance experiments requires the graviton mass to be very small. Such a small graviton mass however implies an ultraviolet cutoff for the theory at length scales far larger than the millimeter scale at which gravity has already been measured. In this paper we attempt to construct a model which avoids this problem. We consider a brane world setup in warped AdS spacetime and we investigate the consequences of writing a mass term for the graviton on a the infrared brane where the local cutoff is of order a large (galactic) distance scale. The advantage of this setup is that the low cutoff for physics on the infrared brane does not significantly affect the predictivity of the theory for observers localized on the ultraviolet brane. For such observers the predictions of this theory agree with general relativity at distances smaller than the infrared scale but go over to those of a theory of massive gravity at longer distances. A careful analysis of the graviton two-point function, however, reveals the presence of a ghost in the low energy spectrum. A mode decomposition of the higher dimensional theory reveals that the ghost corresponds to the radion field. We also investigate the theory with a brane localized mass for the graviton on the ultraviolet brane, and show that the physics of this case is similar to that of a conventional four dimensional theory with a massive graviton, but with one important difference: when the infrared brane decouples and the would-be massive graviton gets heavier than the regular Kaluza-Klein modes, it becomes unstable and it has a finite width to decay off the brane into the continuum of Kaluza-Klein states.
First Order Solutions for Klein-Gordon-Maxwell Equations in a Specific Curved Manifold Case
Murariu, Gabriel
2009-05-22
The aim of this paper is to study the SO(3,1)xU(1) gauge minimally coupled charged spinless field to a spherically symmetric curved space-time. It is derived the first order analytically approximation solution for the system of Klein-Gordon-Maxwell equations. Using these solutions, it evaluated the system electric charge density. The considered space -time manifold generalize an anterior studied one. The chosen space time configuration is of S diagonal type from the MAPLE GRTensor II metrics package.
Analytical solutions of linear and nonlinear Klein-Fock-Gordon equation
NASA Astrophysics Data System (ADS)
Khan, Najeeb Alam; Rasheed, Sajida
2015-03-01
In this paper, we deal with some linear and nonlinear Klein-Fock-Gordon (KFG) equations, which is a relativistic version of the Schrödinger equation. The approximate analytical solutions are obtained by using the homotopy analysis method (HAM). The efficiency of the HAM is that it provides a practical way to control the convergence region of series solutions by introducing an auxiliary parameter }. Analytical results presented are in agreement with the existing results in open literature, which confirm the effectiveness of this method.
The XRD Amorphous Component in John Klein Drill Fines at Yellowknife Bay, Gale Crater, Mars
NASA Technical Reports Server (NTRS)
Morris, Richard V.; Ming,, Douglas W.; Blake, David; Vaniman, David; Bish, David L; Chipera, Steve; Downs, Robert; Morrison, Shaunna; Gellert, Ralf; Campbell, Iain; Treiman, Alan H.; Achilles, Cherie; Bristow, Thomas; Crisp, Joy A.; McAdam, Amy; Archer, Paul Douglas; Sutter, Brad; Rampe, Elizabeth B.
2013-01-01
Drill fines of mudstone (targets John Klein and Cumberland) from the Sheepbed unit at Yel-lowknife Bay were analyzed by MSL payload elements including the Chemistry and Mineralogy (CheMin), APXS (Alpha Particle X-Ray Spectrometer), and Sample Analysis at Mars (SAM) instruments. CheMin XRD results show a variety of crystalline phases including feldspar, pyroxene, olivine, oxides, oxyhydroxides, sulfates, sulfides, a tri-octahedral smectite, and XRD amorphous material. The drill fines are distinctly different from corresponding analyses of the global soil (target Rocknest) in that the mudstone samples contained detectable phyllosilicate. Here we focus on John Klein and combine CheMin and APXS data to calculate the chemical composition and concentration of the amorphous component. The chemical composition of the amorphous plus smectite component for John Klein was calculated by subtracting the abundance-weighted chemical composition of the individual XRD crystalline components from the bulk composition of John Kline as measured by APXS. The chemical composition of individual crystalline components was determined either by stoichiometry (e.g., hematite and magnetite) or from their unit cell parameters (e.g., feldspar, olivine, and pyroxene). The chemical composition of the amorphous + smectite component (approx 71 wt.% of bulk sample) and bulk chemical composition are similar. In order to calculate the chemical composition of the amorphous component, a chemical composition for the tri-octahedral smectite must be assumed. We selected two tri-octahedral smectites with very different MgO/(FeO + Fe2O3) ratios (34 and 1.3 for SapCa1 and Griffithite, respectively). Relative to bulk sample, the concentration of amorphous and smectite components are 40 and 29 wt.% for SapCa1 and 33 and 36 wt.% for Griffithite. The amount of smectite was calculated by requiring the MgO concentration to be approx 0 wt.% in the amorphous component. Griffithite is the preferred smectite because
NASA Astrophysics Data System (ADS)
Koide, T.; Kodama, T.
2015-09-01
The stochastic variational method (SVM) is the generalization of the variational approach to systems described by stochastic variables. In this paper, we investigate the applicability of SVM as an alternative field-quantization scheme, by considering the complex Klein-Gordon equation. There, the Euler-Lagrangian equation for the stochastic field variables leads to the functional Schrödinger equation, which can be interpreted as the Euler (ideal fluid) equation in the functional space. The present formulation is a quantization scheme based on commutable variables, so that there appears no ambiguity associated with the ordering of operators, e.g., in the definition of Noether charges.
Analytical solution of the Klein Gordon equation for a quadratic exponential-type potential
NASA Astrophysics Data System (ADS)
Ezzatpour, Somayyeh; Akbarieh, Amin Rezaei
2016-07-01
In this research study, analytical solutions of the Klein Gordon equation by considering the potential as a quadratic exponential will be presented. However, the potential is assumed to be within the framework of an approximation for the centrifugal potential in any state. The Nikiforov-Uvarov method is used to calculate the wave function, as well as corresponding exact energy equation, in bound states. We finally concluded that the quadratic exponential-type potential under which the results were deduced, led to outcomes that were comparable to the results obtained from the well-known potentials in some special cases.
Using the Bem and Klein Grid Scores to Predict Health Services Usage by Men.
Reynolds, Grace L; Fisher, Dennis G; Dyo, Melissa; Huckabay, Loucine M
2016-01-01
We examined the association between scores on the Bem Sex Roles Inventory (BSRI), Klein Sexual Orientation Grid, and utilization of hospital inpatient services, emergency departments, and outpatient clinic visits in the past 12 months among 53 men (mean age 39 years). The femininity subscale score on the BSRI, ever having had gonorrhea and age were the three variables identified in a multivariate linear regression significantly predicting use of total health services. This supports the hypothesis that sex roles can assist our understanding of men's use of health services. PMID:27337618
Klein tunneling and magnetoresistance of p -n junctions in Weyl semimetals
NASA Astrophysics Data System (ADS)
Li, Songci; Andreev, A. V.; Spivak, B. Z.
2016-08-01
We study the zero temperature conductance and magnetoconductance of ballistic p -n junctions in Weyl semimetals. Electron transport is mediated by Klein tunneling between the n and p regions. The chiral anomaly that is realized in Weyl semimetals plays a crucial role in the magnetoconductance of the junction. With the exception of field orientations where the angle between B and the junction plane is small, magnetoconductance is positive and linear in B at both weak and strong magnetic fields. In contrast, magnetoconductance in conventional p -n junctions is always negative.
The XRD Amorphous Component in John Klein Drill Fines at Yellowknife Bay, Gale Crater, Mars
NASA Astrophysics Data System (ADS)
Morris, R. V.; Ming, D. W.; Blake, D.; Vaniman, D.; Bish, D. L.; Chipera, S.; Downs, R.; Morrison, S.; Gellert, R.; Campbell, I.; Treiman, A. H.; Achilles, C.; Bristow, T.; Crisp, J. A.; McAdam, A.; Archer, P. D.; Sutter, B.; Rampe, E. B.; Team, M.
2013-12-01
Drill fines of mudstone (targets John Klein and Cumberland) from the Sheepbed unit at Yel-lowknife Bay were analyzed by MSL payload elements including the Chemistry and Mineralogy (CheMin), APXS (Alpha Particle X-Ray Spectrometer), and Sample Analysis at Mars (SAM) instruments. CheMin XRD results show a variety of crystalline phases including feldspar, pyrox-ene, olivine, oxides, oxyhydroxides, sulfates, sulfides, a tri-octahedral smectite, and XRD amorphous material. The drill fines are distinctly different from corresponding analyses of the global soil (target Rocknest) in that the mudstone samples contained detectable phyllosilicate. Here we focus on John Klein and combine CheMin and APXS data to calculate the chemical composition and concentration of the amorphous component. The chemical composition of the amorphous plus smectite component for John Klein was cal-culated by subtracting the abundance-weighted chemical composition of the individual XRD crystalline components from the bulk composition of John Kline as measured by APXS. The chemical composition of individual crystalline components was determined either by stoichiome-try (e.g., hematite and magnetite) or from their unit cell parameters (e.g., feldspar, olivine, and pyroxene). The chemical composition of the amorphous + smectite component (~71 wt.% of bulk sample) and bulk chemical compositon are similar. In order to calculate the chemical composition of the amorphous component, a chemical composition for the tri-octahedral smectite must be assumed. We selected two tri-octahedral smectites with very different MgO/(FeO + Fe2O3) ratios (34 and 1.3 for SapCa1 and Griffithite, respectively). Relative to bulk sample, the concentration of amorphous and smectite components are 40 and 29 wt.% for SapCa1 and 33 and 36 wt.% for Griffithite. The amount of smectite was calculated by requiring the MgO concentration to be~0 wt.% in the amporphous component. Griffithite is the preferred smectite because the position
The ideal and the real in Klein and Milton: some observations on reading Paradise Lost.
Steiner, John
2013-10-01
Extracts from Paradise Lost (Milton 1674) are presented to illustrate some ideas of mutual interest to poets and psychoanalysts. In particular, Milton portrays the distinction between the human and the divine in terms of God's perfection and omnipotence, in contrast to man's imperfections. Recognition of this difference can open a painful gap between the self and the ideal, leading to attempts to bridge it via omnipotence. Because we imbue our objects with omnipotence, a similar gap can arise between adult and child and between patient and analyst. Klein's description of the ideal good object highlights similar issues. Both Klein and Milton present the ideal as something important to internalize as a foundation for hope, trust, and belief in goodness, and both emphasize the ideal as something that can be aspired to but not omnipotently realized. Facing this distinction requires a capacity to relinquish and mourn the loss of the good object, as well as the loss of the omnipotence that made possession of it possible. PMID:24194486
Klein and Lacan meet 21st century schizoid man: fairy stories for the modern era.
Charles, Marilyn
2014-09-01
Melanie Klein invited us into the phenomenology of the schizoid dilemma through her depictions of the paranoid-schizoid position. By inserting his recursive arrows, Bion extended this conceptualization, showing us the folly of believing that we can ever entirely move beyond the frightening fantasies and realities of social exclusion and isolation. The 21st century has brought, along with the explosion of technology, an expulsion from the social order of many children who have found refuge from isolation and humiliation in the more accessible and less terrifying world of media and technological invention. What may look like narcissism can mask a terrible underlying schizoid failure to enter into the human race. This is the realm of fantasy run amok, where desire becomes alien and alienated such that one is haunted and hunted down by its very possibility. In this universe, conceptualizations from Klein, Bion, and Lacan help us to locate the individual who has become caught in a massive psychic retreat such that there is no subject because there are no objects. To illustrate, I describe my work with a young man who is living in a terrible "zombie zone" where people are not real and therefore are incomprehensible and terribly dangerous. The poignancy of his dilemma is heartbreaking. Perhaps that is one lesson we can still take from our old fairy tales: when one's heart can be broken by another's plight, then comes the possibility of a healing, an entry through that piercing of what had been impenetrable. PMID:25117781
Efficient and accurate numerical methods for the Klein-Gordon-Schroedinger equations
Bao, Weizhu . E-mail: bao@math.nus.edu.sg; Yang, Li . E-mail: yangli@nus.edu.sg
2007-08-10
In this paper, we present efficient, unconditionally stable and accurate numerical methods for approximations of the Klein-Gordon-Schroedinger (KGS) equations with/without damping terms. The key features of our methods are based on: (i) the application of a time-splitting spectral discretization for a Schroedinger-type equation in KGS (ii) the utilization of Fourier pseudospectral discretization for spatial derivatives in the Klein-Gordon equation in KGS (iii) the adoption of solving the ordinary differential equations (ODEs) in phase space analytically under appropriate chosen transmission conditions between different time intervals or applying Crank-Nicolson/leap-frog for linear/nonlinear terms for time derivatives. The numerical methods are either explicit or implicit but can be solved explicitly, unconditionally stable, and of spectral accuracy in space and second-order accuracy in time. Moreover, they are time reversible and time transverse invariant when there is no damping terms in KGS, conserve (or keep the same decay rate of) the wave energy as that in KGS without (or with a linear) damping term, keep the same dynamics of the mean value of the meson field, and give exact results for the plane-wave solution. Extensive numerical tests are presented to confirm the above properties of our numerical methods for KGS. Finally, the methods are applied to study solitary-wave collisions in one dimension (1D), as well as dynamics of a 2D problem in KGS.
NASA Astrophysics Data System (ADS)
Konkowski, Deborah A.; Arndt, Valerie; Helliwell, Thomas M.
2002-04-01
Klein-Gordon, Maxwell and Dirac fields are studied in quasiregular spacetimes, spacetimes with a classical quasiregular singularity, the mildest true classical singularity [G.F.R. Ellis and B.G. Schmidt, Gen. Rel. Grav.8, 915 (1977)]. A class of static quasiregular spacetimes possessing disclinations and dislocations [R.A. Puntigam and H.H. Soleng, Class. Quantum Grav. 14, 1129 (1997)] is shown to have field operators which are not essentially self-adjoint. This class of spacetimes includes an idealized cosmic string, i.e., a four-dimensional spacetime with a conical singularity [L.H. Ford and A. Vilenkin, J. Phys. A: Math. Gen. 14, 2353 (1981)], and a Galtsov/Letelier/Tod spacetime featuring a screw dislocation [K.P. Tod, Class. Quantum Grav. 11, 1331 (1994); D.V. Galtsov and P.S. Letelier, Phys. Rev. D47, 4273 (1993)]. The definition of G. T. Horowitz and D. Marolf [Phys. Rev. D52, 5670 (1995)] for a quantum-mechanically singular spacetime as one in which the spatial-derivative operator in the Klein-Gordon equation for a massive scalar field is not essentially self-adjoint is extended in the case of quasiregular spacetimes to include Maxwell and Dirac fields. Therefore, the class of static quasiregular spacetimes under consideration is quantum-mechanically singular independent of the type of test field.
Vacuum energy and cosmological supersymmetry breaking in brane worlds [rapid communication
NASA Astrophysics Data System (ADS)
Gravanis, Elias; Mavromatos, Nick E.
2002-11-01
In the context of a toy model we discuss the phenomenon of colliding five-branes, with two of the extra space dimensions compactified on tori. In one of the branes (hidden world) the torus is magnetized. Assuming opposite-tension branes, we argue that the collision results eventually in a (time-dependent) cosmological vacuum energy, whose value today is tiny, lying comfortably within the standard bounds by setting the breaking of the four-dimensional supersymmetry at a TeV scale. The small value of the vacuum energy as compared with the supersymmetry-breaking scale is attributed to transient phenomena with relaxation times of order of the age of the Universe. An interesting feature of the approach is the absence of a cosmic horizon, thereby allowing for a proper definition of an S-matrix. As a result of the string non-criticality induced at the collision, our model does not provide an alternative to inflation, given that arguments can be given supporting the occurrence of an inflationary phase early after the collision. The physics before the collision is not relevant to our arguments on the cosmological constant hierarchy, which are valid for asymptotically long times after it.
From the currency rate quotations onto strings and brane world scenarios
NASA Astrophysics Data System (ADS)
Horváth, D.; Pincak, R.
2012-11-01
In the paper, we study the projections of the real exchange rate dynamics onto the string-like topology. Our approach is inspired by the contemporary movements in the string theory. The string map of data is defined here by the boundary conditions, characteristic length, real valued and the method of redistribution of information. As a practical matter, this map represents the detrending and data standardization procedure. We introduced maps onto 1-end-point and 2-end-point open strings that satisfy the Dirichlet and Neumann boundary conditions. The questions of the choice of extra-dimensions, symmetries, duality and ways to the partial compactification are discussed. Subsequently, we pass to higher dimensional and more complex objects. The 2D-Brane was suggested which incorporated bid-ask spreads. Polarization by the spread was considered which admitted analyzing arbitrage opportunities on the market where transaction costs are taken into account. The model of the rotating string which naturally yields calculation of angular momentum is suitable for tracking of several currency pairs. The systematic way which allows one suggest more structured maps suitable for a simultaneous study of several currency pairs was analyzed by means of the Gâteaux generalized differential calculus. The effect of the string and brane maps on test data was studied by comparing their mean statistical characteristics. The study revealed notable differences between topologies. We review the dependence on the characteristic string length, mean fluctuations and properties of the intra-string statistics. The study explores the coupling of the string amplitude and volatility. The possible utilizations of the string theory approach in financial markets are slight.
Entropy of the Randall-Sundrum brane world with the generalized uncertainty principle
Kim, Wontae; Park, Young-Jai; Kim, Yong-Wan
2006-11-15
By introducing the generalized uncertainty principle, we calculate the entropy of the bulk scalar field on the Randall-Sundrum brane background without any cutoff. We obtain the entropy of the massive scalar field proportional to the horizon area. Here, we observe that the mass contribution to the entropy exists in contrast to all previous results of the usual black hole cases with the generalized uncertainty principle.
A Deconstruction Lattice Description of the D1/D5 Brane World-Volume Gauge Theory
Giedt, Joel
2011-01-01
I genermore » alize the deconstruction lattice formulation of Endres and Kaplan to two-dimensional super-QCD with eight supercharges, denoted by (4,4), and bifundamental matter. I specialize to a particularly interesting (4,4) gauge theory, with gauge group U ( N c ) × U ( N f ) , and U ( N f ) being weakly gauged. It describes the infrared limit of the D1/D5 brane system, which has been studied extensively as an example of the AdS 3 /CFT 2 correspondence. The construction here preserves two supercharges exactly and has a lattice structure quite similar to that which has previously appeared in the deconstruction approach, that is, site, link, and diagonal fields with both the Bose and Fermi statistics. I remark on possible applications of the lattice theory that would test the AdS 3 /CFT 2 correspondence, particularly one that would exploit the recent worldsheet instanton analysis of Chen and Tong.« less
Second Variation of Induced Curvature Term in Brane-World Action
NASA Astrophysics Data System (ADS)
Iofa, Mikhail Z.
In a 5D spacetime with a 3-brane embedded we calculate the second variation of the scalar 4D curvature term on the brane under variations of the 5D metric. It is shown that the second variation of the 4D scalar curvature term in adapted coordinates is expressed only through variations of the components of the 5D metric with 4D indices.
Higher-dimensional bulk wormholes and their manifestations in brane worlds
Rodrigo, Enrico
2006-11-15
There is nothing to prevent a higher-dimensional anti-de Sitter bulk spacetime from containing various other branes in addition to hosting our universe, presumed to be a positive-tension 3-brane. In particular, it could contain closed, microscopic branes that form the boundary surfaces of void bubbles and thus violate the null energy condition in the bulk. The possible existence of such micro branes can be investigated by considering the properties of the ground state of a pseudo-Wheeler-DeWitt equation describing brane quantum dynamics in minisuperspace. If they exist, a concentration of these micro branes could act as a fluid of exotic matter able to support macroscopic wormholes connecting otherwise-distant regions of the bulk. Were the brane constituting our universe to expand into a region of the bulk containing such higher-dimensional macroscopic wormholes, they would likely manifest themselves in our brane as wormholes of normal dimensionality, whose spontaneous appearance and general dynamics would seem inexplicably peculiar. This encounter could also result in the formation of baby universes of a particular type.
Gauged baryon and lepton number in MSSM{sub 4} brane worlds
Lebed, Richard F.; Mayes, Van E.
2011-10-01
A recent D-brane model designed to accommodate a phenomenologically acceptable fourth generation of chiral fermions was noted to produce an unexpected additional unbroken nonanomalous U(1) gauge group at the string scale. We show that the corresponding charges acting on minimal supersymmetric standard model fields count baryon and lepton numbers. If broken spontaneously at lower scales, these U(1){sub B} and U(1){sub L} symmetries provide potential avenues for preserving baryogenesis while nonetheless explaining the suppression of proton decay (without the need for R parity), as well as the smallness of right-handed neutrino Majorana masses compared to the string scale.
On the localisation of four-dimensional brane-world black holes: II. The general case
NASA Astrophysics Data System (ADS)
Kanti, P.; Pappas, N.; Pappas, T.
2016-01-01
We perform a comprehensive analysis of a number of scalar field theories in an attempt to find analytically five-dimensional, localised-on-the-brane, black-hole solutions. Extending a previous analysis, we assume a generalised Vaidya ansatz for the five-dimensional metric tensor that allows for a time-dependent, non-trivial profile of the mass function in terms of the bulk coordinate and a deviation from the over-restricting Schwarzschild-type solution on the brane. In order to support such a solution, we study a variety of theories including single or multiple scalar fields, with canonical or non-canonical kinetic terms, minimally or non-minimally coupled to gravity. We demonstrate that for such a metric ansatz and for a carefully chosen energy-momentum tensor which is non-isotropic in five dimensions, solutions that have the form of a Schwarzschild-(anti)de Sitter or Reissner-Nordstrom type of solution do emerge. However, the resulting profile of the mass function along the bulk coordinate, when allowed, is not the correct one for eliminating bulk singularities.
Feeling unreal: a functional imaging study in patients with Kleine-Levin syndrome.
Kas, Aurelie; Lavault, Sophie; Habert, Marie-Odile; Arnulf, Isabelle
2014-07-01
Kleine-Levin syndrome is characterized by relapsing-remitting episodes of severe hypersomnia, cognitive impairment, apathy, derealization and behavioural disturbances. Between episodes, patients have normal sleep, mood and behaviour. Functional imaging studies performed in small series of patients with Kleine-Levin syndrome with visual or semi-quantitative, uncontrolled analysis yielded equivocal brain changes. Using whole brain voxel-based group analysis, we compared brain perfusion scintigraphy during and between episodes in consecutive patients with Kleine-Levin syndrome versus healthy control subjects and correlated perfusion changes with disease severity and symptoms, focusing on less studied but disabling symptoms, such as apathy and derealization. During asymptomatic periods, 41 patients (mean age of 22.3 ± 8.1 years, 56.1% male) and 15 age- and sex-matched healthy control subjects underwent single-photon emission computed tomography scanning with technetium-99m ethyl cysteinate dimer. Eleven patients repeated the test during a symptomatic period. Compared with controls, patients during asymptomatic periods had persistent hypoperfusion in the hypothalamus, the thalamus (mainly the right posterior part), the caudate nucleus, and cortical associative areas, including the anterior cingulate, (Brodmann area 25), the orbito-frontal (Brodmann area 11) and the right superior temporal cortices (Brodmann area 22), extending to the insula (P < 0.001 in all area). Two additional hypoperfused areas emerged during symptomatic periods (P < 0.001), located in the right dorsomedial prefrontal cortex (Brodmann area 8) and the right parieto-temporal junction (Brodmann areas 22 and 39). These two areas were more affected between episodes, when the mean episode duration was longer (r = -0.53; P < 0.001). The score for the Depersonalization/Derealization Inventory during symptomatic periods strongly correlated with the hypoperfusion of the right (r = -0.74, P < 0.001) and left
Nebhinani, Naresh; Avasthi, Ajit; Modi, Manish
2015-01-01
Kleine-Levin syndrome (KLS) is characterized by recurrent episodes of hypersomnia and other symptoms and it is a really challenging for the physician, since its causes are not yet clear, and available treatment options are not having adequate support. Here, we are reporting a case with successful use of valproate in KLS and also reviewing the cases reported from India. PMID:26664089
NASA Astrophysics Data System (ADS)
Villalba, Víctor M.; Catalá, Esteban Isasi
2002-10-01
We solve the Klein-Gordon and Dirac equations in an open cosmological universe with a partially horn topology in the presence of a time dependent magnetic field. Since the exact solution cannot be obtained explicitly for arbitrary time dependence of the field, we discuss the asymptotic behavior of the solutions with the help of the relativistic Hamilton-Jacobi equation.
NASA Astrophysics Data System (ADS)
Ita, B. I.; Obong, H. P.; Ehi-Eromosele, C. O.; Edobor-Osoh, A.; Ikeuba, A. I.
2014-11-01
The solutions of the Klein-Gordon equation with equal scalar and vector harmonic oscillator plus inverse quadratic potential for S-waves have been presented using the Nikiforov-Uvarov method. The bound state energy eigenvalues and the corresponding un-normalized eigenfunctions are obtained in terms of the Laguerre polynomials.
NASA Astrophysics Data System (ADS)
Nakanishi, K.; Schlag, W.
2012-03-01
We extend our result Nakanishi and Schlag in J. Differ. Equ. 250(5):2299-2333, 2011) to the non-radial case, giving a complete classification of global dynamics of all solutions with energy that is at most slightly above that of the ground state for the nonlinear Klein-Gordon equation with the focusing cubic nonlinearity in three space dimensions.
Comparison of associated Higgs boson-radion and Higgs boson pair production processes
NASA Astrophysics Data System (ADS)
Boos, E.; Keizerov, S.; Rakhmetov, E.; Svirina, K.
2016-07-01
Many models—in particular, the brane-world models with two branes—predict the existence of the scalar radion, whose mass can be somewhat smaller than those of all the Kaluza-Klein modes of the graviton and Standard Model (SM) particles. Due to its origin the radion interacts with the trace of the energy-momentum tensor of the SM. The fermion part of the radion interaction Lagrangian is different from that for the SM Higgs boson due to the presence of additional terms playing a role for off-shell fermions. It was shown previously [Phys. Rev. D 90, 095026 (2014), 10.1103/PhysRevD.90.095026] that for the case of the single radion and single Higgs boson production processes in association with an arbitrary number of SM gauge bosons all the contributions to the perturbative amplitudes appearing due to these additional terms were canceled out, making the processes similar up to a replacement of masses and overall coupling constants. For the case of the associated Higgs boson-radion and the Higgs boson pair-production processes involving the SM gauge bosons, the similarity property also appears. However, a detailed consideration shows that in this case it is not enough to simply replace the masses and the constants (mh→mr and v →Λr). One should also rescale the triple Higgs coupling by the factor ξ ≡1 +m/r2-mh2 3 mh2 .
Dark energy and the hierarchy problem
NASA Astrophysics Data System (ADS)
Chen, Pisin
2009-03-01
The well-known hierarchy between the Planck scale (˜10GeV) and the TeV scale, namely a ratio of ˜10 between the two, is coincidentally repeated in a inverted order between the TeV scale and the dark energy scale at ˜10eV implied by the observations. We argue that this is not a numerical coincidence. The same brane-world setups to address the first hierarchy problem may also in principle address this second hierarchy issue. Specifically, we consider supersymmetry in the bulk and its breaking on the brane and resort to the Casimir energy induced by the bulk graviton-gravitino mass-shift on the brane as the dark energy. For the ADD model we found that our notion is sensible only if the number of extra dimension n=2. We extend our study to the Randall-Sundrum model. Invoking the chirality-flip on the boundaries for SUSY-breaking, the zero-mode gravitino contribution to the Casimir energy does give rise to the double hierarchy. Unfortunately since the higher Kaluza-Klein modes acquire relative mass-shifts at the TeV level, the zero-mode contribution to Casimir energy is overshadowed.
Gravity localization on hybrid branes
NASA Astrophysics Data System (ADS)
Veras, D. F. S.; Cruz, W. T.; Maluf, R. V.; Almeida, C. A. S.
2016-03-01
This work deals with gravity localization on codimension-1 brane worlds engendered by compacton-like kinks, the so-called hybrid branes. In such scenarios, the thin brane behavior is manifested when the extra dimension is outside the compact domain, where the energy density is non-trivial, instead of asymptotically as in the usual thick brane models. The zero mode is trapped in the brane, as required. The massive modes, although not localized in the brane, have important phenomenological implications such as corrections to the Newton's law. We study such corrections in the usual thick domain wall and in the hybrid brane scenarios. By means of suitable numerical methods, we attain the mass spectrum for the graviton and the corresponding wavefunctions. The spectra possess the usual linearly increasing behavior from the Kaluza-Klein theories. Further, we show that the 4D gravitational force is slightly increased at short distances. The first eigenstate contributes highly for the correction to the Newton's law. The subsequent normalized solutions have diminishing contributions. Moreover, we find out that the phenomenology of the hybrid brane is not different from the usual thick domain wall. The use of numerical techniques for solving the equations of the massive modes is useful for matching possible phenomenological measurements in the gravitational law as a probe to warped extra dimensions.
NASA Astrophysics Data System (ADS)
Loup, Fernando
2006-10-01
We use the Conformal Metric as described in Kar Sinha work on Gravitational Bending of Light in a 5 D Spacetime to recompute the equations of the 5 D Force in Basini Capozziello Ponce De Leon Formalism and we arrive at a result that possesses some advantages. The equations of the Extra Force as proposed by Ponce De Leon are now more elegant in Conformal Formalism and many algebraic terms can be simplified or even suppressed. Also we recompute the Kar Sinha Gravitational Bending of Light affected by the presence of the Extra Dimension and analyze the Superluminal Chung Freese Features of this Formalism describing the advantages of the Chung Freese BraneWorld when compared to other Superluminal spacetime metrics (e.g. Warp Drive) and we describe why the Extra Dimension is invisible and how the Extra Dimension could be made visible at least in theory. We also examine the Maartens Clarkson Black Holes in 5 D (Black Strings) coupled to massive Kaluza Klein graviton modes predicted by Extra Dimensions theories and we study experimental detection of Extra Dimensions on-board LIGO and LISA Space Telescopes. We also propose the use of International Space Station (ISS) to measure the additional terms (resulting from the presence of Extra Dimensions) in the Kar Sinha Gravitational Bending of Light in Outer Space to verify if we really lives in a Higher Dimensional Spacetime. Also we demonstrate that Particle Z can only exist if the 5 D spacetime exists.
Magnetic Breakdown and Klein Tunneling in a Type-II Weyl Semimetal.
O'Brien, T E; Diez, M; Beenakker, C W J
2016-06-10
The band structure of a type-II Weyl semimetal has pairs of electron and hole pockets that coexist over a range of energies and touch at a topologically protected conical point. We identify signatures of this Weyl point in the magnetic quantum oscillations of the density of states, observable in thermodynamic properties. Tunneling between the electron and hole pockets in a magnetic field is the momentum space counterpart of Klein tunneling at a p-n junction in real space. This magnetic breakdown happens at a characteristic field strength that vanishes when the Fermi level approaches the Weyl point. The topological distinction between connected and disconnected pairs of type-II Weyl cones can be distinguished by the qualitatively different dependence of the quantum oscillations on the direction of the magnetic field. PMID:27341246
Eab, C. H.; Lim, S. C.; Teo, L. P.
2007-08-15
This paper studies the Casimir effect due to fractional massless Klein-Gordon field confined to parallel plates. A new kind of boundary condition called fractional Neumann condition which involves vanishing fractional derivatives of the field is introduced. The fractional Neumann condition allows the interpolation of Dirichlet and Neumann conditions imposed on the two plates. There exists a transition value in the difference between the orders of the fractional Neumann conditions for which the Casimir force changes from attractive to repulsive. Low and high temperature limits of Casimir energy and pressure are obtained. For sufficiently high temperature, these quantities are dominated by terms independent of the boundary conditions. Finally, validity of the temperature inversion symmetry for various boundary conditions is discussed.
Magnetic Breakdown and Klein Tunneling in a Type-II Weyl Semimetal
NASA Astrophysics Data System (ADS)
O'Brien, T. E.; Diez, M.; Beenakker, C. W. J.
2016-06-01
The band structure of a type-II Weyl semimetal has pairs of electron and hole pockets that coexist over a range of energies and touch at a topologically protected conical point. We identify signatures of this Weyl point in the magnetic quantum oscillations of the density of states, observable in thermodynamic properties. Tunneling between the electron and hole pockets in a magnetic field is the momentum space counterpart of Klein tunneling at a p -n junction in real space. This magnetic breakdown happens at a characteristic field strength that vanishes when the Fermi level approaches the Weyl point. The topological distinction between connected and disconnected pairs of type-II Weyl cones can be distinguished by the qualitatively different dependence of the quantum oscillations on the direction of the magnetic field.
Carvalho, Evanilda Souza de Santana; Araújo, Edna Maria de; Santos, Silvone Santa Bárbara da Silva; Santos, Alexandro Gesner Gomes Dos
2016-06-01
Objectives To analyze the representations of the nurse and individual in mental suffering portrayed in the photographic work by Steven Klein, in the USAnatomy exhibit held at the Museum of Sculpture (Museu da escultura) in São Paulo, in 2011. Methods Qualitative study carried out in 2012. Three photographs were submitted to iconographic analysis. The interpretation of the findings was based on theoretical frameworks of Foucault and Bourdieu on power relations. Results The nurse is represented as a sensual, insensitive person, with the power to control and torture while the person in psychological distress is represented as dirty, imprisoned and subjected to an asymmetrical relationship of power with the nurse. Final considerations Relationships of submission and symbolic dominance, in which the person in psychological distress has their body molded by discipline imposed by the nurse. Stereotypes of the image of the nurse oppose the ideology of the profession, which is to ensure the integrity of those being cared for. PMID:27253591
Klein-Gordon equation and reflection of Alfven waves in nonuniform media
NASA Technical Reports Server (NTRS)
Musielak, Z. E.; Fontenla, J. M.; Moore, R. L.
1992-01-01
A new analytical approach is presented for assessing the reflection of linear Alfven waves in smoothly nonuniform media. The general one-dimensional case in Cartesian coordinates is treated. It is shown that the wave equations, upon transformation into the form of the Klein-Gordon equation, display a local critical frequency for reflection. At any location in the medium, reflection becomes strong as the wave frequency descends past this characteristic frequency set by the local nonuniformity of the medium. This critical frequecy is given by the transformation as an explicit function of the Alfven velocity and its first and second derivatives, and hence as an explicit spatial function. The transformation thus directly yields, without solution of the wave equations, the location in the medium at which an Alfven wave of any given frequency becomes strongly reflected and has its propagation practically cut off.
Sharp comparison theorems for the Klein-Gordon equation in d dimensions
NASA Astrophysics Data System (ADS)
Hall, Richard L.; Zorin, Petr
2016-06-01
We establish sharp (or ’refined’) comparison theorems for the Klein-Gordon equation. We show that the condition Va ≤ Vb, which leads to Ea ≤ Eb, can be replaced by the weaker assumption Ua ≤ Ub which still implies the spectral ordering Ea ≤ Eb. In the simplest case, for d = 1, Ui(x) =∫0xV i(t)dt, i = a or b and for d > 1, Ui(r) =∫0rV i(t)td‑1dt, i = a or b. We also consider sharp comparison theorems in the presence of a scalar potential S (a ‘variable mass’) in addition to the vector term V (the time component of a four-vector). The theorems are illustrated by a variety of explicit detailed examples.
Dynamical Hamiltonian-Hopf instabilities of periodic traveling waves in Klein-Gordon equations
NASA Astrophysics Data System (ADS)
Marangell, R.; Miller, P. D.
2015-07-01
We study the unstable spectrum close to the imaginary axis for the linearization of the nonlinear Klein-Gordon equation about a periodic traveling wave in a co-moving frame. We define dynamical Hamiltonian-Hopf instabilities as points in the stable spectrum that are accumulation points for unstable spectrum, and show how they can be determined from the knowledge of the discriminant of Hill's equation for an associated periodic potential. This result allows us to give simple criteria for the existence of dynamical Hamiltonian-Hopf instabilities in terms of instability indices previously shown to be useful in stability analysis of periodic traveling waves. We also discuss how these methods can be applied to more general nonlinear wave equations.
Klein-Gordon Solutions on Non-Globally Hyperbolic Standard Static Spacetimes
NASA Astrophysics Data System (ADS)
Bullock, David M. A.
2012-11-01
We construct a class of solutions to the Cauchy problem of the Klein-Gordon equation on any standard static spacetime. Specifically, we have constructed solutions to the Cauchy problem based on any self-adjoint extension (satisfying a technical condition: "acceptability") of (some variant of) the Laplace-Beltrami operator defined on test functions in an L2-space of the static hypersurface. The proof of the existence of this construction completes and extends work originally done by Wald. Further results include: the uniqueness of these solutions; their support properties; the construction of the space of solutions and the energy and symplectic form on this space; an analysis of certain symmetries on the space of solutions; and various examples of this method, including the construction of a non-bounded below acceptable self-adjoint extension generating the dynamics.
Kleine-Levin Syndrome: An Overview and Relevance to Nursing Practice.
Arnone, Jacqueline M; Conti, Richard P
2016-03-01
Kleine-Levin syndrome (KLS) is a neuropsychiatric sleep disorder primarily affecting adolescent males. Onset is insidious, idiopathic, and hastened by neurological incident or infection. Typically, the initial onset occurs during the teen years or after the second decade, although cases have been documented in early childhood, adulthood, and senescence. KLS is marked by unexpected debilitating, yet reversible, episodic hypersomnia, with varying recurrence rates; cognitive and behavioral impairment; compulsive eating; and feelings of derealization, hypersexuality, apathy, and depressed mood. Diagnosis is problematic due to the syndrome's rarity, disparity of presenting clinical symptoms, and misdiagnosis. Correct diagnosis can take up to 4 years. The clinical course is approximately 8 to 14 years from initial onset, yet may be longer in the adult form of the disorder. KLS has been shown to impact activities of daily living, usurping an adolescent of his/her social relations with peers, experiences, and time. PMID:26935190
Didactic derivation of the special theory of relativity from the Klein-Gordon equation
NASA Astrophysics Data System (ADS)
Arodź, H.
2014-09-01
We present a didactic derivation of the special theory of relativity in which Lorentz transformations are ‘discovered’ as symmetry transformations of the Klein-Gordon equation. The interpretation of Lorentz boosts as transformations to moving inertial reference frames is not assumed at the start, but it naturally appears at a later stage. The relative velocity v of two inertial reference frames is defined in terms of the elements of the pertinent Lorentz matrix, and the bound |{\\bf v}| is presented as a simple theorem that follows from the structure of the Lorentz group. The polar decomposition of Lorentz matrices is used to explain noncommutativity and nonassociativity of the relativistic composition (‘addition’) of velocities.
A channel sediment budget for the 'Kleine Noordwaard' in the Biesbosch area, the Netherlands
NASA Astrophysics Data System (ADS)
van der Deijl, Eveline C.; van der Perk, Marcel; Zonneveld, Wouter; Verschelling, Eelco; Middelkoop, Hans
2015-04-01
Many deltas in the world are subject to drowning and loss of land due to accelerated soil subsidence, sea level rise, and sediment starvation. Effective delta restoration requires a thorough understanding of the rates and mechanisms of delta aggradation and their controls. This study aims to quantify the rates and patterns of aggradation in the Kleine Noordwaard, a former polder area in the Biesbosch area in the south-west of the Netherlands, in which water and sediment have been reintroduced since 2009. A sediment budget was established using existing bathymetric data collected using a multibeam echosounder and LiDAR digital elevation models collected since the opening of the polder, supplemented with field observations of the location and height of cut banks carried out between July and December 2014. Consecutive measurements of channel bathymetry showed a positive sediment budget in the channels between March 2009 and March 2013. During this period 59533 m3 of sediment was retained in the channels in the Kleine Noordwaard, which corresponds to an average sedimentation rate of 16.8 mm/year in the channels and 3.4 mm/year over the entire area. Sedimentation and aggradation primarily took place in the channels in the central part of the former polder area, whereas the channels near the entrance and outlet of the area underwent considerable erosion. It is therefore likely that a part of the sediment deposited in the central part of the system was supplied internally by upstream erosion of the channels. The results from the field observations suggest that cut-bank retreat also significantly contributes to internal sediment redistribution.
NASA Astrophysics Data System (ADS)
Wu, Xinyuan; Liu, Changying
2016-02-01
In this paper, we are concerned with the initial boundary value problem of arbitrarily high-dimensional Klein-Gordon equations, posed on a bounded domain Ω ⊂ ℝd for d ≥ 1 and equipped with the requirement of boundary conditions. We derive and analyze an integral formula which is proved to be adapted to different boundary conditions for general Klein-Gordon equations in arbitrarily high-dimensional spaces. The formula gives a closed-form solution to arbitrarily high-dimensional homogeneous linear Klein-Gordon equations, which is totally different from the well-known D'Alembert, Poisson, and Kirchhoff formulas. Some applications are included as well.
Phantom black holes and sigma models
Azreg-Aienou, Mustapha; Clement, Gerard; Fabris, Julio C.; Rodrigues, Manuel E.
2011-06-15
We construct static multicenter solutions of phantom Einstein-Maxwell-dilaton theory from null geodesics of the target space, leading to regular black holes without spatial symmetry for certain discrete values of the dilaton coupling constant. We also discuss the three-dimensional gravitating sigma models obtained by reduction of phantom Einstein-Maxwell, phantom Kaluza-Klein and phantom Einstein-Maxwell-dilaton-axion theories. In each case, we generate by group transformations phantom charged black hole solutions from a neutral seed.
NASA Astrophysics Data System (ADS)
Nakao, Mitsuhiro
We prove the existence of global decaying solutions to the exterior problem for the Klein-Gordon equation with a nonlinear localized dissipation and a derivative nonlinearity. To derive the required estimates of solutions we employ a 'loan' method.
NASA Astrophysics Data System (ADS)
Vitória, R. L. L.; Furtado, C.; Bakke, K.
2016-07-01
The relativistic quantum dynamics of an electrically charged particle subject to the Klein-Gordon oscillator and the Coulomb potential is investigated. By searching for relativistic bound states, a particular quantum effect can be observed: a dependence of the angular frequency of the Klein-Gordon oscillator on the quantum numbers of the system. The meaning of this behaviour of the angular frequency is that only some specific values of the angular frequency of the Klein-Gordon oscillator are permitted in order to obtain bound state solutions. As an example, we obtain both the angular frequency and the energy level associated with the ground state of the relativistic system. Further, we analyse the behaviour of a relativistic position-dependent mass particle subject to the Klein-Gordon oscillator and the Coulomb potential.
EPR & Klein Paradoxes in Complex Hamiltonian Dynamics and Krein Space Quantization
NASA Astrophysics Data System (ADS)
Payandeh, Farrin
2015-07-01
Negative energy states are applied in Krein space quantization approach to achieve a naturally renormalized theory. For example, this theory by taking the full set of Dirac solutions, could be able to remove the propagator Green function's divergences and automatically without any normal ordering, to vanish the expected value for vacuum state energy. However, since it is a purely mathematical theory, the results are under debate and some efforts are devoted to include more physics in the concept. Whereas Krein quantization is a pure mathematical approach, complex quantum Hamiltonian dynamics is based on strong foundations of Hamilton-Jacobi (H-J) equations and therefore on classical dynamics. Based on complex quantum Hamilton-Jacobi theory, complex spacetime is a natural consequence of including quantum effects in the relativistic mechanics, and is a bridge connecting the causality in special relativity and the non-locality in quantum mechanics, i.e. extending special relativity to the complex domain leads to relativistic quantum mechanics. So that, considering both relativistic and quantum effects, the Klein-Gordon equation could be derived as a special form of the Hamilton-Jacobi equation. Characterizing the complex time involved in an entangled energy state and writing the general form of energy considering quantum potential, two sets of positive and negative energies will be realized. The new states enable us to study the spacetime in a relativistic entangled “space-time” state leading to 12 extra wave functions than the four solutions of Dirac equation for a free particle. Arguing the entanglement of particle and antiparticle leads to a contradiction with experiments. So, in order to correct the results, along with a previous investigation [1], we realize particles and antiparticles as physical entities with positive energy instead of considering antiparticles with negative energy. As an application of modified descriptions for entangled (space
NASA Astrophysics Data System (ADS)
Ikot, A. N.; Obong, H. P.; Abbey, T. M.; Zare, S.; Ghafourian, M.; Hassanabadi, H.
2016-05-01
In this article we use supersymmetry quantum mechanics and factorization methods to study the bound and scattering state of Klein-Gordon equation with deformed Hulthen plus deformed hyperbolical potential for arbitrary state in D-dimensions. The analytic relativistic bound state eigenvalues and the scattering phase factor are found in closed form. We report on the numerical results for the bound state energy in D-dimensions.
NASA Astrophysics Data System (ADS)
Lucio Rapoport, Diego
2013-04-01
We present a unified principle for science that surmounts dualism, in terms of torsion fields and the non-orientable surfaces, notably the Klein Bottle and its logic, the Möbius strip and the projective plane. We apply it to the complex numbers and cosmology, to non-linear systems integrating the issue of hyperbolic divergences with the change of orientability, to the biomechanics of vision and the mammal heart, to the morphogenesis of crustal shapes on Earth in connection to the wavefronts of gravitation, elasticity and electromagnetism, to pattern recognition of artificial images and visual recognition, to neurology and the topographic maps of the sensorium, to perception, in particular of music. We develop it in terms of the fundamental 2:1 resonance inherent to the Möbius strip and the Klein Bottle, the minimal surfaces representation of the wavefronts, and the non-dual Klein Bottle logic inherent to pattern recognition, to the harmonic functions and vector fields that lay at the basis of geophysics and physics at large. We discuss the relation between the topographic maps of the sensorium, and the issue of turning inside-out of the visual world as a general principle for cognition, topological chemistry, cell biology and biological morphogenesis in particular in embryology
NASA Astrophysics Data System (ADS)
Mu, Xiyu; Cheng, Hao; Liu, Guoqing
2016-04-01
It is often difficult to provide the exact boundary condition in the practical use of variational method. The Euler equation derived from variational method cannot be solved without boundary condition. However, in some application problems such as the assimilation of remote sensing data, the values can be easily obtained in the inner region of the domain. Since the solution of elliptic partial differential equations continuously depends on the boundary condition, the boundary condition can be retrieved using part solutions in the inner area. In this paper, the variational problem of remote sensing data assimilation within a circular area is first established. The Klein-Gordon elliptic equation is derived from the Euler method of variational problems with assumed boundary condition. Secondly, a computer-friendly Green function is constructed for the Dirichlet problem of two-dimensional Klein-Gordon equation, with the formal solution according to Green formula. Thirdly, boundary values are retrieved by solving the optimal problem which is constructed according to the smoothness of boundary value function and the best approximation between formal solutions and high-accuracy measurements in the interior of the domain. Finally, the assimilation problem is solved on substituting the retrieved boundary values into the Klein-Gordon equation. It is a type of inverse problem in mathematics. The advantage of our method lies in that it needs no assumptions of the boundary condition. It thus alleviates the error introduced by artificial boundary condition in data fusion using variational method in the past.
A local energy-preserving scheme for Klein-Gordon-Schrödinger equations
NASA Astrophysics Data System (ADS)
Cai, Jia-Xiang; Wang, Jia-Lin; Wang, Yu-Shun
2015-05-01
A local energy conservation law is proposed for the Klein-Gordon-Schrödinger equations, which is held in any local time-space region. The local property is independent of the boundary condition and more essential than the global energy conservation law. To develop a numerical method preserving the intrinsic properties as much as possible, we propose a local energy-preserving (LEP) scheme for the equations. The merit of the proposed scheme is that the local energy conservation law can hold exactly in any time-space region. With the periodic boundary conditions, the scheme also possesses the discrete change and global energy conservation laws. A nonlinear analysis shows that the LEP scheme converges to the exact solutions with order 𝒪(τ2 + h2). The theoretical properties are verified by numerical experiments. Project supported by the National Natural Science Foundation of China (Grant Nos. 11201169, 11271195, and 41231173) and the Project of Graduate Education Innovation of Jiangsu Province, China (Grant No. CXLX13 366).
Valley permitted Klein tunneling and magnetoresistance in ferromagnetic monolayer MoS2
NASA Astrophysics Data System (ADS)
Khezerlou, M.; Goudarzi, H.
2015-10-01
Recently, effect of proximity-induced ferromagnetism or superconductivity in two dimensional monolayer molybdenum disulfide on the energy dispersion of relativistic charge carriers has attracted much effort. Inequivalent nondegenerate K and K‧ valleys resulted from strong spin-orbit coupling in monolayer MoS2 give rise to obtain novel behaviors in some physical phenomena, such as Andreev reflection or spin-valley transport properties, comparing with corresponding structure, graphene. Considerable direct band-gap in monolayer MoS2 makes it potentially useful for electronics applications. Motivated by these, we study, in particular, the influence of various combinations of valley and spin indices on charge transmission in the MoS2 -based ferromagnetic/insulator/ferromagnetic junction. It is shown that the tunneling process is suppressed with arbitrary range of chemical potential for all incident electrons. We determine the exact magnitude of Fermi energy by chemical potential. Topological and mass-related terms (α, β) are taken into account in the Dirac-like Hamiltonian, and conductance resulted from the transmission probability is investigated in terms of physical parameters of structure. We, further, study the dependence of the magnetoresistance on exchange field for various cases of valley-coupling. Magnetoresistance of system is changed from a positive value to negative for K valley, only. The Klein tunneling is resulted in different exhibitations for different allowed spin and valley indices. As expected, the exact oscillations of transmission coefficient is found in terms of barrier parameter.
Critical and noncritical long-range entanglement in Klein-Gordon fields
Marcovitch, S.; Reznik, B.; Retzker, A.; Plenio, M. B.
2009-07-15
We investigate the entanglement between two spatially separated intervals in the vacuum state of a free one-dimensional Klein-Gordon field by means of explicit computations in the continuum limit of the linear harmonic chain. We demonstrate that the entanglement, which we quantify by the logarithmic negativity, is finite with no further need for renormalization. We find that in the critical regime, the quantum correlations are scale invariant as they depend only on the ratio of distance to length. They decay much faster than the classical correlations as in the critical limit long-range entanglement decays exponentially for separations larger than the size of the blocks, while classical correlations follow a power-law decay. With decreasing distance of the blocks, the entanglement diverges as a power law in the distance. The noncritical regime manifests richer behavior, as the entanglement depends both on the size of the blocks and on their separation. In correspondence with the von Neumann entropy also long-range entanglement distinguishes critical from noncritical systems.
Hunting the ghosts of a 'strictly quantum field': the Klein-Gordon equation
NASA Astrophysics Data System (ADS)
Bertozzi, Eugenio
2010-11-01
This paper aims to identify and tackle some problems related to teaching quantum field theory (QFT) at university level. In particular, problems arising from the canonical quantization are addressed by focusing on the Klein-Gordon equation (KGE). After a brief description of the status of the KGE in teaching as it emerges from an analysis of a selected sample of university textbooks, an analysis of the applications of the KGE in contexts different from the QFT is presented. The results of the analysis show that, while in the real case the solutions of the equation can be easily interpreted from a physical point of view, in the complex case the coherence with relativistic quantum mechanics and the electrodynamics framework brings to light interpretative problems related to the classical complex KG field. The comparison between the classical cases investigated and the QFT framework, where the equation finds a coherent particle interpretation, leads to share Ryder's statement asserting that the KG field is a 'strictly quantum field'. Implications of the results in terms of remarks about the canonical procedure currently utilized for teaching are underlined.
Hydromagnetic waves in a compressed-dipole field via field-aligned Klein-Gordon equations
NASA Astrophysics Data System (ADS)
Zheng, Jinlei; Hu, Qiang; Webb, Gary M.; McKenzie, James F.
2016-05-01
Hydromagnetic waves, especially those of frequencies in the range of a few millihertz to a few hertz observed in the Earth's magnetosphere, are categorized as ultra low-frequency (ULF) waves or pulsations. They have been extensively studied due to their importance in the interaction with radiation belt particles and in probing the structures of the magnetosphere. We developed an approach to examining the toroidal standing Aflvén waves in a background magnetic field by recasting the wave equation into a Klein-Gordon (KG) form along individual field lines. The eigenvalue solutions to the system are characteristic of a propagation type when the corresponding eigenfrequency is greater than a critical frequency and a decaying type otherwise. We apply the approach to a compressed-dipole magnetic field model of the inner magnetosphere and obtain the spatial profiles of relevant parameters and the spatial wave forms of harmonic oscillations. We further extend the approach to poloidal-mode standing Alfvén waves along field lines. In particular, we present a quantitative comparison with a recent spacecraft observation of a poloidal standing Alfvén wave in the Earth's magnetosphere. Our analysis based on the KG equation yields consistent results which agree with the spacecraft measurements of the wave period and the amplitude ratio between the magnetic field and electric field perturbations.
Quantum breathers in Klein-Gordon lattice: Non-periodic boundary condition approach
NASA Astrophysics Data System (ADS)
Mandal, Subhra Jyoti; Choudhary, Kamal; Biswas, Arindam; Bandyopadhyay, A. K.; Bhattacharjee, A. K.; Mandal, D.
2011-12-01
The presence of classical breathers and two-phonon bound state (TPBS) or quantum breather (QB) state through detailed quantum calculations have already been shown in technologically important ferroelectric materials, such as lithium niobate with antisite niobium charge defects concerning pinning transition, its control, and application. The latter was done in a periodic boundary condition with Bloch function in terms of significant variations of TPBS parameters against impurity, which is related to nonlinearity. In further extension of this work, in a non-periodic boundary condition and number-conserving approach, apart from various techniques available, only the temporal evolution of the number of quanta (i.e., phonons) in more sites is detailed in this present investigation for a generalized Klein-Gordon system with applications in ferroelectrics, metamaterials, and DNA. The critical time of redistribution of quanta that is proportional to the QB's lifetime in these materials shows different types of behavior in the femtosecond range, which gives rise to the possibilities for making various devices.
Solitons and chaos of the Klein-Gordon-Zakharov system in a high-frequency plasma
NASA Astrophysics Data System (ADS)
Zhen, Hui-Ling; Tian, Bo; Sun, Ya; Chai, Jun; Wen, Xiao-Yong
2015-10-01
In this paper, we study the Klein-Gordon-Zakharov (KGZ) system, which describes the interaction between the Langmuir wave and ion sound wave in a high-frequency plasma. By means of the Hirota method and symbolic computation, bright and mixed-type soliton solutions are obtained. For the one soliton, amplitude of E is positively related to β 2 , and that of n is inversely related to β 2 , while they are both positively related to α, where E refers to the high-frequency part of the electrostatic potential of the electric field raised by the electrons, and n represents the deviation of ion density from its equilibrium, β 2 and α are the plasma frequency and ion sound speed, respectively. Head-on interactions between the two bright solitons and two mixed-type ones are respectively displayed. With β 2 increasing, the head-on interaction is transformed into an overtaking one. Bright bound-state solitons are investigated, and the interaction period decreases with α increasing. Furthermore, with the external forces Γ 1 ( t ) and Γ 2 ( t ) introduced, the perturbed KGZ system is studied numerically for its associated chaotic motions. Both the weak and developed chaotic motions can be observed. Γ 1 ( t ) and Γ 2 ( t ) have different effects on the chaotic motions: the chaotic motion can be weakened by decreasing the amplitude of Γ 1 ( t ) or increasing the amplitude and frequency of Γ 2 ( t ) .
Contact doping, Klein tunneling, and asymmetry of shot noise in suspended graphene
NASA Astrophysics Data System (ADS)
Laitinen, Antti; Paraoanu, G. S.; Oksanen, Mika; Craciun, Monica F.; Russo, Saverio; Sonin, Edouard; Hakonen, Pertti
2016-01-01
The inherent asymmetry of the electric transport in graphene is attributed to Klein tunneling across barriers defined by p n interfaces between positively and negatively charged regions. By combining conductance and shot noise experiments, we determine the main characteristics of the tunneling barrier (height and slope) in a high-quality suspended sample with Au/Cr/Au contacts. We observe an asymmetric resistance Rodd=100 -70 Ω across the Dirac point of the suspended graphene at carrier density | nG|=(0.3 -4 ) × 1011cm-2 , while the Fano factor displays a nonmonotonic asymmetry in the range Fodd˜0.03 -0.1. Our findings agree with analytical calculations based on the Dirac equation with a trapezoidal barrier. Comparison between the model and the data yields the barrier height for tunneling, an estimate of the thickness of the p n interface d <20 nm, and the contact region doping corresponding to a Fermi level offset of ˜-18 meV. The strength of pinning of the Fermi level under the metallic contact is characterized in terms of the contact capacitance Cc=19 ×10-6 F/cm2 . Additionally, we show that the gate voltage corresponding to the Dirac point is given by the difference in work functions between the backgate material and graphene.
A response to Rudolf Klein: a battle may have been won but perhaps not the war.
Hunter, David J
2013-08-01
The British National Health Service (NHS) is undergoing possibly the most far-reaching set of changes in its sixty-five-year history. While some commentators (like Rudolf Klein) insist that little of substance is likely to change, others consider that the politics of reform may prove quite different on this occasion. The coalition government is committed to restructuring the welfare state and public services and to rolling back the state. The NHS as a popular monopoly public service runs counter to its neoliberal ideology. While (for now) remaining committed to a publicly funded system of health care that is largely free at point of use, the government wishes to encourage much greater diversity in the provision of care, including a much larger role for the for-profit private sector. Despite significant opposition to its proposals, few concessions have been forthcoming, and the legislation that passed onto the statute book in March 2012 remained essentially unchanged. Notwithstanding the lack of convincing evidence, the government is wedded to encouraging greater competition and choice. Thosewho believe the changes will amount to far less than its architects hope for are being too complacent and overlooking the strength of the government's ideological convictions. These threaten to dismantle the NHS and replace it with a more costly, fragmented, and less effective system of care that is driven by profit in place of the public interest. PMID:23645872
Generalized and functional separable solutions to nonlinear delay Klein-Gordon equations
NASA Astrophysics Data System (ADS)
Polyanin, Andrei D.; Zhurov, Alexei I.
2014-08-01
We describe a number of generalized separable, functional separable, and some other exact solutions to nonlinear delay Klein-Gordon equations of the formutt=kuxx+F(u,w), where u=u(x,t) and w=u(x,t-τ), with τ denoting the delay time. The generalized separable solutions are sought in the form u=∑n=1NΦn(x)Ψn(t), where the functions Φn(x) and Ψn(t) are to be determined subsequently. Most of the equations considered contain one or two arbitrary functions of a single argument or one arbitrary function of two arguments of special form. We present a substantial number of new exact solutions, including periodic and antiperiodic ones, as well as composite solutions resulting from a nonlinear superposition of generalized separable and traveling wave solutions. All solutions involve free parameters (in some cases, infinitely many) and so can be suitable for solving certain problems and testing approximate analytical and numerical methods for nonlinear delay PDEs.
Diagnosis, disease course, and management of patients with Kleine-Levin syndrome.
Arnulf, Isabelle; Rico, Thomas J; Mignot, Emmanuel
2012-10-01
Kleine-Levin syndrome is a rare sleep disorder that mainly affects adolescents and is characterised by relapsing-remitting episodes of severe hypersomnia, cognitive impairment, apathy, derealisation, and psychiatric and behavioural disturbances. Boys are more frequently affected than girls. Just over half of patients have hyperphagia, are hypersexual (mainly boys), or have depressed mood (mainly girls), and 30% become anxious, delusional, and have hallucinations. Although some symptoms are similar to those in patients with encephalopathy, imaging and laboratory findings are unremarkable. The first episode of hypersomnia is often triggered by an infection, with relapses occurring every 1-12 months for a median of 14 years; disease duration can be much longer with childhood or adult onset than in patients with adolescent onset. Between episodes, patients generally have normal sleep patterns, cognition, mood, and eating habits. During episodes, electroencephalography might show diffuse or local slow activity. Functional imaging studies have revealed hypoactivity in thalamic and hypothalamic regions, and in the frontal and temporal lobes. Stimulants and mood stabilisers can be beneficial in the treatment of severe cases. PMID:22995695
Huygens' principle for the Klein-Gordon equation in the de Sitter spacetime
Yagdjian, Karen
2013-09-15
In this article we prove that the Klein-Gordon equation in the de Sitter spacetime obeys the Huygens' principle only if the physical mass m of the scalar field and the dimension n⩾ 2 of the spatial variable are tied by the equation m{sup 2}= (n{sup 2}−1)/4. Moreover, we define the incomplete Huygens' principle, which is the Huygens' principle restricted to the vanishing second initial datum, and then reveals that the massless scalar field in the de Sitter spacetime obeys the incomplete Huygens' principle and does not obey the Huygens' principle, for the dimensions n= 1, 3, only. Thus, in the de Sitter spacetime the existence of two different scalar fields (in fact, with m= 0 and m{sup 2}= (n{sup 2}−1)/4), which obey incomplete Huygens' principle, is equivalent to the condition n= 3, the spatial dimension of the physical world. In fact, Paul Ehrenfest in 1917 addressed the question: “Why has our space just three dimensions?”. For n= 3 these two values of the mass are the endpoints of the so-called in quantum field theory the Higuchi bound. The value m{sup 2}= (n{sup 2}−1)/4 of the physical mass allows us also to obtain complete asymptotic expansion of the solution for the large time.
Gromov, E.M.; Talanov, V.I.
1992-01-01
Questions relating to the penetration of fields into supercritical regions of inhomogeneous media are of considerable interest both for fundamental studies in wave theory and for applied problems in various areas of physics. In strong fields this penetration is related to nonlinear restructuring of the parameters of the medium under the action of the field itself. In weak fields penetration is possible when a strong wave in the parameters of the medium is present and are facilitated if the dynamic states undergo frequency shifts in the inhomogeneous medium in the presence of this wave. Such states have been quite well studied for fields described by equations such as the Schroedinger equation. At the same time it was noted that dynamic field states can exist which are described by the Klein-Gordon equation. In the present work we study the dynamic states of such fields in the presence of a parameter wave. We point out the possibility of entraining packets of the field by this wave. The efficiency with which these entrained states are excited is determined for a parameter wave in the form of a discontinuous shock. 12 refs.
Killing superalgebra deformations of ten-dimensional supergravity backgrounds
NASA Astrophysics Data System (ADS)
Figueroa-O'Farrill, José; Vercnocke, Bert
2007-12-01
We explore Lie superalgebra deformations of the Killing superalgebras of some ten-dimensional supergravity backgrounds. We prove the rigidity of the Poincaré superalgebras in types I, IIA and IIB, as well as of the Killing superalgebra of the Freund Rubin vacuum of type IIB supergravity. We also prove rigidity of the Killing superalgebras of the NS5-, D0-, D3-, D4- and D5-branes, whereas we exhibit the possible deformations of the D1-, D2-, D6- and D7-brane Killing superalgebras, as well as of that of the type II fundamental string solutions. We relate the superalgebra deformations of the D2- and D6-branes to those of the (delocalized) M2-brane and the Kaluza Klein monopole, respectively. The good behaviour under Kaluza Klein reduction suggests that the deformed superalgebras ought to have a geometric interpretation.
Atalić, Bruno; Fatović-Ferencić, Stella
2009-10-01
The new Appendix A of the European Convention for the Protection of Vertebrate Animals Used for Experimental and Other Scientific Purposes, which gives guidelines for accommodation and care of animals and was approved on June 15, 2006, was the main reason the authors decided to investigate the origins of the regulations of animal experiments. Although one might assume that the regulation had its origin in the United Nations conventions, the truth is that its origins are a hundred years old. The authors present a case of the nineteenth-century vivisection controversy brought about by the publication of the Handbook for the Physiological Laboratory in 1873, in which John Burdon-Sanderson, Emanuel Edward Klein, Michael Foster, and Thomas Lauder Brunton described a series of vivisection experiments they performed on animals for research purposes. It was the first case of vivisection to be examined, processed, and condemned for inhuman behavior toward animals before an official body, leading to enactment of the Cruelty to Animals Act in 1876. The case reveals a specific ethos of science in the second half of the nineteenth century, which was characterized by a deep commitment of scientists to the scientific enterprise and their strong belief that science could solve social problems, combined with an overt insensitivity to the suffering of experimental animals. The central figure in the case was Emanuel Edward Klein, a disciple of the Central European medical tradition (Vienna Medical School) and a direct follower of the experimental school of Brücke, Stricker, Magendie, and Bernard. Because of his undisguised attitudes and opinions on the use of vivisection, Klein became a paradigm of the new scientific identity, strongly influencing the stereotypic image of a scientist, and polarizing the public opinion on vivisection in England in the nineteenth century and for some considerable time afterward. PMID:19690150
NASA Technical Reports Server (NTRS)
Hall, Dorothy K.; Bayr, Klaus J.; Schoener, Wolfgang; Bindschadler, Robert A.; Chien, Janet Y. L.
2002-01-01
The tongue of the Pasterze Glacier in the eastern Alps of Austria receded more than 1152 m from 1880 to 2001. Landsat and Ikonos satellite data from 1976 to 2001, topographic maps beginning in 1893 and ground measurements were studied. Results show that though satellite images significantly underestimate the width of the Pasterze Glacier tongue due to the presence of morainal material on the surface, they provide an excellent way to measure the recession of the exposed-ice part of the glacier tongue. The rate of change of the terminus as determined using satellite data is found to compare well with ground measurements. Between 1976 and 2001, Landsat-derived measurements show a recession of the terminus of the Pasterze Glacier of 479+/-113 m (at an average rate of 18.4 m a(exp -1) while measurements from the ground showed a recession of 428 m (at an average recession of 17.1 m a(exp -1). Ikonos satellite images from 2000 and 2001 reveal changes in the exposed ice part of the Pasterze tongue, and a decrease in area of the exposed ice part of the tongue of 22,096 sq m. GPS points and a ground survey of the glacier terminus in August 2001 were plotted on a 1-m resolution Ikonos image, and showed the actual terminus shape and location. The nearby Kleines Fleisskees glacier lost 30% of its area between 1984 and 2001, and the area of exposed ice increased by 0.44 sq km, according to Landsat satellite measurements. Recession of both the Pasterze and the Kleines Fleisskees corresponds generally to temperature and precipitation trends, especially increasing summer temperatures, as determined from meteorological data acquired from the Sonnblick Observatory, however the smaller the Kleines FleiSkees reacts more quickly to climate changes than does the Pasterze Glacier.
NASA Astrophysics Data System (ADS)
LeFloch, Philippe G.; Ma, Yue
2016-01-01
The Hyperboloidal Foliation Method (introduced by the authors in 2014) is extended here and applied to the Einstein equations of general relativity. Specifically, we establish the nonlinear stability of Minkowski spacetime for self-gravitating massive scalar fields, while existing methods only apply to massless scalar fields. First of all, by analyzing the structure of the Einstein equations in wave coordinates, we exhibit a nonlinear wave-Klein-Gordon model defined on a curved background, which is the focus of the present paper. For this model, we prove here the existence of global-in-time solutions to the Cauchy problem, when the initial data have sufficiently small Sobolev norms. A major difficulty comes from the fact that the class of conformal Killing fields of Minkowski space is significantly reduced in the presence of a massive scalar field, since the scaling vector field is not conformal Killing for the Klein-Gordon operator. Our method relies on the foliation (of the interior of the light cone) of Minkowski spacetime by hyperboloidal hypersurfaces and uses Lorentz-invariant energy norms. We introduce a frame of vector fields adapted to the hyperboloidal foliation and we establish several key properties: Sobolev and Hardy-type inequalities on hyperboloids, as well as sup-norm estimates, which correspond to the sharp time decay for the wave and the Klein-Gordon equations. These estimates allow us to control interaction terms associated with the curved geometry and the massive field by distinguishing between two levels of regularity and energy growth and by a successive use of our key estimates in order to close a bootstrap argument.
NASA Astrophysics Data System (ADS)
Xu, Xiao-Ge; Gao, Yi-Tian; Wei, Guang-Mei
In this paper, the nonlinear Klein-Gordon equation describing the propagation of pulse waves in plasma or waveguide is investigated. With symbolic computation, the generalized Bäcklund Transformations (BTs) for this equation are constructed under different conditions. It is shown that the BTs published in the previous literature for the Sine-Gordon equation, Sinh-Gordon equation, and Liouville equation all turn out to be special cases of the results in the present paper. Moreover, the corresponding Lax pairs are explicitly derived from the obtained BTs through some transformations.
NASA Astrophysics Data System (ADS)
Alonso-Mallo, I.; Portillo, A. M.
2016-04-01
Klein-Gordon equations on an unbounded domain are considered in one dimensional and two dimensional cases. Numerical computation is reduced to a finite domain by using the Hagstrom-Warburton (H-W) high-order absorbing boundary conditions (ABCs). Time integration is made by means of exponential splitting schemes that are efficient and easy to implement. In this way, it is possible to achieve a negligible error due to the time integration and to study the behavior of the absorption error. Numerical experiments displaying the accuracy of the numerical solution for the two dimensional case are provided. The influence of the dispersion coefficient on the error is also studied.
NASA Astrophysics Data System (ADS)
Saha Ray, S.; Sahoo, S.
2016-07-01
In this paper, homotopy perturbation transform method and modified homotopy analysis method have been applied to obtain the approximate solutions of the time fractional coupled Klein-Gordon-Zakharov equations. We consider fractional coupled Klein-Gordon-Zakharov equation with appropriate initial values using homotopy perturbation transform method and modified homotopy analysis method. Here we obtain the solution of fractional coupled Klein-Gordon-Zakharov equation, which is obtained by replacing the time derivatives with a fractional derivatives of order α ∈ (1, 2], β ∈ (1, 2]. Through error analysis and numerical simulation, we have compared approximate solutions obtained by two present methods homotopy perturbation transform method and modified homotopy analysis method. The fractional derivatives here are described in Caputo sense.
NASA Astrophysics Data System (ADS)
Suárez, Abril; Chavanis, Pierre-Henri
2015-07-01
Using a generalization of the Madelung transformation, we derive the hydrodynamic representation of the Klein-Gordon-Einstein equations in the weak field limit. We consider a complex self-interacting scalar field with a λ |φ |4 potential. We study the evolution of the spatially homogeneous background in the fluid representation and derive the linearized equations describing the evolution of small perturbations in a static and in an expanding Universe. We compare the results with simplified models in which the gravitational potential is introduced by hand in the Klein-Gordon equation, and assumed to satisfy a (generalized) Poisson equation. Nonrelativistic hydrodynamic equations based on the Schrödinger-Poisson equations or on the Gross-Pitaevskii-Poisson equations are recovered in the limit c →+∞. We study the evolution of the perturbations in the matter era using the nonrelativistic limit of our formalism. Perturbations whose wavelength is below the Jeans length oscillate in time while perturbations whose wavelength is above the Jeans length grow linearly with the scale factor as in the cold dark matter model. The growth of perturbations in the scalar field model is substantially faster than in the cold dark matter model. When the wavelength of the perturbations approaches the cosmological horizon (Hubble length), a relativistic treatment is mandatory. In that case, we find that relativistic effects attenuate or even prevent the growth of perturbations. This paper exposes the general formalism and provides illustrations in simple cases. Other applications of our formalism will be considered in companion papers.
NASA Astrophysics Data System (ADS)
Hack, Thomas-Paul
2014-11-01
We quantize the linearized Einstein-Klein-Gordon system on arbitrary on-shell backgrounds in a manifestly covariant and gauge-invariant manner. For the special case of perturbations in inflation, i.e. on-shell backgrounds of Friedmann-Lemaître-Robertson-Walker type, we compare our general quantization construction with the standard approach to the quantum theory of perturbations in inflation. We find that not all local quantum observables of the linearized Einstein-Klein-Gordon system can be split into local observables of scalar and tensor type as in the standard approach. However, we argue that this subclass of observables is sufficient for measuring perturbations that vanish at spatial infinity, which is in line with standard assumptions. Finally, we comment on a recent observation that, upon standard quantization, the quantum Bardeen potentials display a non-local behaviour and argue that a similar phenomenon occurs in any local quantum field theory. It is the hope of the author that the present work may constitute a bridge between the generally applicable and thus powerful framework of algebraic quantum field theory in curved spacetimes and the standard treatment of perturbations in inflation.
Numerical Studies of Nonlinear Schrodinger and Klein-Gordon Systems: Techniques and Applications
NASA Astrophysics Data System (ADS)
Choi, Dae-Il
The continuing proliferation of computational resources makes it more and more powerful to conduct numerical studies on physics problems for which either analytic methods fail, or well-controlled experiments are very difficult, if not impossible. In particular, a finite-difference based numerical approach. has been an indispensable tool in the three areas of physics that, I study in this thesis: numerical relativity (boson stars), Bose-Einstein condensates, and atomic hydrogen in strong laser fields. Numerical relativity (NR) enables us to tackle problems of astrophysical interest which are difficult or impossible to study using analytic methods. Many of these problems involve strong and dynamical gravitational fields, and many involve the dynamics of one or more gravitationally compact objects such as black holes, neutron stars or, more speculatively, boson stars. A long term goal of NR, then (and of this research) is the accurate simulation of the dynamics of one or more compact objects. Here, as a step in that direction, I present some of the first results for a fully coupled Einstein/Klein-Gordon system in 3D, wherein I attempt to evolve a static relativistic boson star using the full equations of motion. A key motivation for the study of self-gravitating bosonic matter (in both the Newtonian and Einsteinian regimes) is the observation that, even though any direct physical relevance has yet to be demonstrated, boson star systems provide excellent numerical laboratories in which to develop techniques for NR. Specifically, the boson star model provides an ideal vehicle with which to implement and evaluate (1) various coordinate conditions in the context of the ADM formalism and (2) multidimensional adaptive mesh refinement techniques which appear crucial for many problems in 3D numerical relativity. Again, as a step towards studying the fully relativistic problem, I first consider boson stars in the Newtonian regime, which are described by the solutions of Schr
NASA Astrophysics Data System (ADS)
Kononets, Y. V.
2010-05-01
An algebraic block-diagonalization of the Dirac Hamiltonian in a time-independent external field reveals a charge-index conservation law which forbids the physical phenomena of the Klein paradox type and guarantees a single-particle nature of the Dirac equation in strong external fields. Simultaneously, the method defines simpler quantum-mechanical objects—paulions and antipaulions, whose 2-component wave functions determine the Dirac electron states through exact operator relations. Based on algebraic symmetry, the presented theory leads to a new understanding of the Dirac equation physics, including new insight into the Dirac measurements and a consistent scheme of relativistic quantum mechanics of electron in the paulion representation. Along with analysis of the mathematical anatomy of the Klein paradox falsity, a complete set of paradox-free eigenfunctions for the Klein problem is obtained and investigated via stationary solutions of the Pauli-like equations with respective paulion Hamiltonians. It is shown that the physically correct Dirac states in the Klein zone are characterized by the total particle reflection from the potential step and satisfy the fundamental charge-index conservation law.
ERIC Educational Resources Information Center
Rothstein, Richard
2010-01-01
Joel Klein, chancellor of the New York City public school system, and Michelle Rhee, who resigned October 13 as Washington, D.C. chancellor, published a "manifesto" in the "Washington Post" claiming that the difficulty of removing incompetent teachers "has left our school districts impotent and, worse, has robbed millions of children of a real…
NASA Astrophysics Data System (ADS)
Sergyeyev, Artur; Krtouš, Pavel
2008-02-01
We consider the Klein-Gordon equation in generalized higher-dimensional Kerr-NUT-(A)dS spacetime without imposing any restrictions on the functional parameters characterizing the metric. We establish commutativity of the second-order operators constructed from the Killing tensors found in [J. High Energy Phys.JHEPFG1029-8479 02 (2007) 00410.1088/1126-6708/2007/02/004] and show that these operators, along with the first-order operators originating from the Killing vectors, form a complete set of commuting symmetry operators (i.e., integrals of motion) for the Klein-Gordon equation. Moreover, we demonstrate that the separated solutions of the Klein-Gordon equation obtained in [J. High Energy Phys.JHEPFG1029-8479 02 (2007) 00510.1088/1126-6708/2007/02/005] are joint eigenfunctions for all of these operators. We also present an explicit form of the zero mode for the Klein-Gordon equation with zero mass. In the semiclassical approximation we find that the separated solutions of the Hamilton-Jacobi equation for geodesic motion are also solutions for a set of Hamilton-Jacobi-type equations which correspond to the quadratic conserved quantities arising from the above Killing tensors.
Sergyeyev, Artur; Krtous, Pavel
2008-02-15
We consider the Klein-Gordon equation in generalized higher-dimensional Kerr-NUT-(A)dS spacetime without imposing any restrictions on the functional parameters characterizing the metric. We establish commutativity of the second-order operators constructed from the Killing tensors found in [J. High Energy Phys. 02 (2007) 004] and show that these operators, along with the first-order operators originating from the Killing vectors, form a complete set of commuting symmetry operators (i.e., integrals of motion) for the Klein-Gordon equation. Moreover, we demonstrate that the separated solutions of the Klein-Gordon equation obtained in [J. High Energy Phys. 02 (2007) 005] are joint eigenfunctions for all of these operators. We also present an explicit form of the zero mode for the Klein-Gordon equation with zero mass. In the semiclassical approximation we find that the separated solutions of the Hamilton-Jacobi equation for geodesic motion are also solutions for a set of Hamilton-Jacobi-type equations which correspond to the quadratic conserved quantities arising from the above Killing tensors.
NASA Astrophysics Data System (ADS)
Tang, Bing; Li, De-Jun
2016-05-01
A theoretical work on quantum breathers in a nonlinear Klein-Gordon lattice model with nearest and next-nearest neighbor interactions is presented. The semiclassical and the full quantum cases are respectively considered. For the semiclassical case, we obtain the analytical solution of discrete breather, and find that the wave number corresponding to the appearance of discrete breather changes when the ratio of the next-nearest- to -nearest - neighbor harmonic force constants is greater than 1/4. For the full quantum case, by calculating the energy spectrum of the system containing two quanta, we prove numerically the existence of quantum breathers (two-quanta bound states) and find the shape of energy spectrum changes dramatically as the value of next -nearest neighbor harmonic force constant increasing.
NASA Astrophysics Data System (ADS)
Babin, Anatoli; Figotin, Alexander
2013-09-01
Einstein's relation E = Mc 2 between the energy E and the mass M is the cornerstone of the relativity theory. This relation is often derived in a context of the relativistic theory for closed systems which do not accelerate. By contrast, the Newtonian approach to the mass is based on an accelerated motion. We study here a particular neoclassical field model of a particle governed by a nonlinear Klein-Gordon (KG) field equation. We prove that if a solution to the nonlinear KG equation and its energy density concentrate at a trajectory, then this trajectory and the energy must satisfy the relativistic version of Newton's law with the mass satisfying Einstein's relation. Therefore the internal energy of a localized wave affects its acceleration in an external field as the inertial mass does in Newtonian mechanics. We demonstrate that the "concentration" assumptions hold for a wide class of rectilinear accelerating motions.
NASA Astrophysics Data System (ADS)
Vigier, Jean-Pierre
1991-02-01
Starting from a nonlinear relativistic Klein-Gordon equation derived from the stochastic interpretation of quantum mechanics (proposed by Bohm-Vigier, (1) Nelson, (2) de Broglie, (3) Guerra et al. (4) ), one can construct joint wave and particle, soliton-like solutions, which follow the average de Broglie-Bohm (5) real trajectories associated with linear solutions of the usual Schrödinger and Klein-Gordon equations.
Dziewinski, Jacek J.; Marczak, Stanislaw
2000-01-01
Nitrates are reduced to nitrogen gas by contacting the nitrates with a metal to reduce the nitrates to nitrites which are then contacted with an amide to produce nitrogen and carbon dioxide or acid anions which can be released to the atmosphere. Minor amounts of metal catalysts can be useful in the reduction of the nitrates to nitrites. Metal salts which are formed can be treated electrochemically to recover the metals.
NASA Astrophysics Data System (ADS)
Jafarnejad, Mona; Pfister, Michael; Franca, Mário J.; Schleiss, Anton J.
2014-05-01
Potential failure for river bank protection measures is a critical issue to be evaluated for the safety and stability assessment. Moreover, uncertainties associated to flood conditions and sediment transport in rivers, as a possible result of climate change in the future, affects the safety level of such riverbank protection structures as riprap and walls. Bank failure can lead to uncontrolled erosion and flooding with disastrous consequences in residential areas or in critical infrastructures. The probabilistic analysis of failure on different mechanisms due to possible flood events and sediment transport is a principal step to assess embankment stability in future scenarios. Herein, a probabilistic risk assessment model to define the failure risk of river bank ripraps, developed based on Monte Carlo simulation and Moment Analysis Methods, is showed. This probabilistic simulation estimates the resistance of ripraps regarding varied flood and sediment transport scenarios in future. The failure probability of ripraps is assessed by a probabilistic function of the design safety factor. The probability of failure in different mechanisms such as direct block erosion, toe scouring and overtopping is defined by taking into account the modified bed-load transport due to a probabilistic function of the design discharge. This evaluation method is applied to a Swiss river located in Canton Lucerne, the Kleine Emme. The results highlight the failure probability of riverbank riprap associated to different mechanisms individually. A risk map to represent the risk of total failure along a longitudinal profile of the river is proposed.
Prado de Oliveira, L E
1995-01-01
Starting from The Freud-Klein Controversies, the author explores the historical reality of these controversies and their transformations into myth which give them the appearance of titanic fights. The verification of the different periods, the description of the variations in themes and style of intervention of the principal actors of these debates show aspects of the way a psychoanalytic institute works and of the theoretical elaboration in psychoanalysis: these appear very different from what the myth suggests. The major function of myth is, as Freud noted and Strachey reminds us, to hide very trite, even shameful realities. History and myth, theoritical effort and institutional life are all organized from and around transference, a major axis of psychoanalytic thought. When we organize our psychoanalytic lives in societies, we have the pride or the vanity of participating in a great historical movement. This goes back to the work of transference in institutional life that involves primal objects in the crudeness of their sexuality. Such is the constraining strength of transference. Being fully conscious of it, like Stratchey or Balint show us, enables to alleviate its violence and stimulate creativity. PMID:8559850
Nedelmann, Carl
2005-08-01
The paper is written from a personal perspective and in conjunction with the author's participation in editing Hillel Klein's book Uberleben und Versuche der Wiederbelebung-Psychoanalytische Studien mit Uberlebenden der Shoah und mit ihren Familien in Israel und in der Diaspora [Survival and trials of revival--Psychodynamic studies of Holocaust survivors and their families in Israel and the diaspora] which appeared posthumously in 2003. The manuscript was originally written in English during the first half of the 1980s. It consists of a revised version of his contributions to psychoanalytic Holocaust research, as well as further observations and a number of autobiographical features. It suggests that we see the symptom which relates to the traumatic past less as the sign of a pathology, and instead, through the linking of drives and objects, more as a sign of hope. The hope is that revival begins in recovering the world that was lost in the Holocaust, the world from before, which, as torn as it was, he still referred to as the 'intact world'. He regarded rapprochement as one of the main therapeutic tools. Rapprochement does not build up absolutes, but leaves from the quantitative point of view room for encounter. PMID:16040313
NASA Astrophysics Data System (ADS)
Suárez, Abril; Matos, Tonatiuh
2014-02-01
In this paper, the thermal evolution of scalar field dark matter (SFDM) particles at finite cosmological temperatures is studied. Starting with a real SF in a thermal bath and using the one-loop quantum corrections potential, we rewrite Klein-Gordon’s equation in its hydrodynamical representation and study the phase transition of this SF due to a Z2 symmetry breaking of its potential. A very general version of a nonlinear Schrödinger equation is obtained. When introducing Madelung’s representation, the continuity and momentum equations for a non-ideal SFDM fluid are formulated, and the cosmological scenario with the SFDM described in analogy to an imperfect fluid is then considered where dissipative contributions are obtained in a natural way. Additional terms appear in the results compared to those in the classical version commonly used to describe the ΛCDM model, i.e., the ideal fluid. The equations and parameters that characterize the physical properties of the system such as its energy, momentum and viscous flow are related to the temperature of the system, scale factor, Hubble’s expansion parameter and the matter energy density. Finally, some details on how galaxy halos and smaller structures might be able to form by condensation of this SF are given.
NASA Astrophysics Data System (ADS)
Pesci, Adriana I.; Goldstein, Raymond E.; Uys, Hermann
2005-05-01
In previous work we have shown that the quantum potential can be derived from the classical kinetic equations both for particles with and without spin. Here, we extend these mappings to the relativistic case. The essence of the analysis consists of Fourier transforming the momentum coordinate of the distribution function. This procedure introduces a natural parameter η with units of angular momentum. In the non-relativistic case the ansatz of either separability, or separability and additivity, imposed on the probability distribution function produces mappings onto the Schrödinger equation and the Pauli equation, respectively. The former corresponds to an irrotational flow, the latter to a fluid with non-zero vorticity. In this work we show that the relativistic mappings lead to the Klein-Gordon equation in the irrotational case and to the second-order Dirac equation in the rotational case. These mappings are irreversible; an approximate inverse is the Wigner function. Taken together, these results provide a statistical interpretation of quantum mechanics.
Complex structures for an S-matrix of Klein-Gordon theory on AdS spacetimes
NASA Astrophysics Data System (ADS)
Dohse, Max; Oeckl, Robert
2015-05-01
While the standard construction of the S-matrix fails on anti-de Sitter (AdS) spacetime, a generalized S-matrix makes sense, based on the hypercylinder geometry induced by the boundary of AdS. In contrast to quantum field theory in Minkowski spacetime, there is not yet a standard way to resolve the quantization ambiguities arising in its construction. These ambiguities are conveniently encoded in the choice of a complex structure. We explore in this paper the space of complex structures for real scalar Klein-Gordon theory based on a number of criteria. These are: invariance under AdS isometries, induction of a positive definite inner product, compatibility with the standard S-matrix picture and recovery of standard structures in Minkowski spacetime under a limit of vanishing curvature. While there is no complex structure that satisfies all demands, we emphasize two interesting candidates that satisfy most: in one case we have to give up part of the isometry invariance, and in the other case the induced inner product is indefinite.
Hamilton, M.A. )
1990-11-01
During a radon gas screening program, elevated levels of radon gas were detected in homes on Mackinac Island, Mich. Six homes on foundations with crawl spaces were selected for a research project aimed at reducing radon gas concentrations, which ranged from 12.9 to 82.3 pCi/l. Using isolation and ventilation techniques, and variations thereof, radon concentrations were reduced to less than 1 pCi/l. This paper reports that these reductions were achieved using 3.5 mil cross laminated or 10 mil high density polyethylene plastic as a barrier without sealing to the foundation or support piers, solid and/or perforated plastic pipe and mechanical fans. Wind turbines were found to be ineffective at reducing concentrations to acceptable levels. Homeowners themselves installed all materials.
Klein, Fritz; McCutchan, J. Allen; Grant, Igor
2014-01-01
We used a cluster analysis to empirically address whether sexual orientation is a continuum or can usefully be divided into categories such as heterosexual, homosexual, and bisexual using scores on the Klein Sexual Orientation Grid (KSOG) in three samples: groups of men and women recruited through bisexual groups and the Internet (Main Study men; Main Study women), and men recruited for a clinical study of HIV and the nervous system (HIV Study men). A five-cluster classification was chosen for the Main Study men (n = 212), a four-cluster classification for the Main Study women (n = 120), and a five-cluster classification for the HIV Study men (n = 620). We calculated means and standard deviations of these 14 clusters on the 21 variables composing the KSOG. Generally, the KSOG’s overtly erotic items (Sexual Fantasies, Sexual Behavior, and Sexual Attraction), as well as the Self Identification items, tended to be more uniform within groups than the more social items were (Emotional Preference, Socialize with, and Lifestyle). The result is a set of objectively identified subgroups of bisexual men and women along with characterizations of the extent to which their KSOG scores describe and differentiate them. The Bisexual group identified by the cluster analysis of the HIV sample was distinctly different from any of the bisexual groups identified by the clustering process in the Main Sample. Simply put, the HIV sample’s bisexuality is not like bisexuality in general, and attempts to generalize (even cautiously) from this clinical Bisexual group to a larger population would be doomed to failure. This underscores the importance of recruiting non-clinical samples if one wants insight into the nature of bisexuality in the population at large. Although the importance of non-clinical sampling in studies of sexual orientation has been widely and justly asserted, it has rarely been demonstrated by direct comparisons of the type conducted in the present study. PMID:25530727
Gallet, Basile; Nazarenko, Sergey; Dubrulle, Bérengère
2015-07-01
In field theory, particles are waves or excitations that propagate on the fundamental state. In experiments or cosmological models, one typically wants to compute the out-of-equilibrium evolution of a given initial distribution of such waves. Wave turbulence deals with out-of-equilibrium ensembles of weakly nonlinear waves, and is therefore well suited to address this problem. As an example, we consider the complex Klein-Gordon equation with a Mexican-hat potential. This simple equation displays two kinds of excitations around the fundamental state: massive particles and massless Goldstone bosons. The former are waves with a nonzero frequency for vanishing wave number, whereas the latter obey an acoustic dispersion relation. Using wave-turbulence theory, we derive wave kinetic equations that govern the coupled evolution of the spectra of massive and massless waves. We first consider the thermodynamic solutions to these equations and study the wave condensation transition, which is the classical equivalent of Bose-Einstein condensation. We then focus on nonlocal interactions in wave-number space: we study the decay of an ensemble of massive particles into massless ones. Under rather general conditions, these massless particles accumulate at low wave number. We study the dynamics of waves coexisting with such a strong condensate, and we compute rigorously a nonlocal Kolmogorov-Zakharov solution, where particles are transferred nonlocally to the condensate, while energy cascades towards large wave numbers through local interactions. This nonlocal cascading state constitutes the intermediate asymptotics between the initial distribution of waves and the thermodynamic state reached in the long-time limit. PMID:26274249
Dual technicolor with hidden local symmetry
Belitsky, A. V.
2010-08-15
We consider a dual description of the technicolor-like gauge theory within the D4/D8-brane configuration with varying confinement and electroweak symmetry breaking scales. Constructing an effective truncated model valid below a certain cutoff, we identify the particle spectrum with Kaluza-Klein modes of the model in a manner consistent with the hidden local symmetry. Integrating out heavy states, we find that the low-energy action receives nontrivial corrections stemming from the mixing between standard model and heavy gauge bosons, which results in reduction of oblique parameters.
Vector boson production in association with KK modes of the ADD model to NLO in QCD at the LHC
NASA Astrophysics Data System (ADS)
Kumar, M. C.; Mathews, Prakash; Ravindran, V.; Seth, Satyajit
2011-05-01
Next-to-leading order (NLO) QCD corrections to the associated production of the vector boson (Z/W±) with the Kaluza-Klein (KK) modes of the graviton in large extra-dimensional model at the Large Hadron Collider (LHC) are presented. We have obtained various kinematic distributions using a Monte Carlo code which is based on the two-cutoff phase space slicing method that handles soft and collinear singularities appearing at the NLO level. We estimate the impact of the QCD corrections on various observables and find that they are significant. We also show the reduction in factorization scale uncertainty when QCD corrections are included.
NASA Astrophysics Data System (ADS)
Jia, Chun-Sheng; Chen, Tao; He, Su
2013-03-01
By employing the improved Greene-Aldrich approximation scheme to deal with the centrifugal term, we solve approximately the Klein-Gordon equation with the improved expression of the Manning-Rosen empirical potential energy model. The bound state energy equation and the unnormalized radial wave functions have been approximately obtained by using the supersymmetric WKB approach and the function analysis method. The relativistic vibrational transition frequencies for the a3Σu+ state of 7Li2 molecule have been computed by using the Manning-Rosen potential model. The relativistic vibrational transition frequencies are in good agreement with the observed data.
NASA Astrophysics Data System (ADS)
Chen, Chang-Yuan; Lu, Fa-Lin; Sun, Dong-Sheng
2008-12-01
In this paper, using the exponential function transformation approach along with an approximation for the centrifugal potential, the radial Klein-Gordon equation with the vector and scalar Hulthén potential is transformed to a hypergeometric differential equation. The approximate analytical solutions of t-waves scattering states are presented. The normalized wave functions expressed in terms of hypergeometric functions of scattering states on the “ k/2π scale” and the calculation formula of phase shifts are given. The physical meaning of the approximate analytical solution is discussed.
NASA Astrophysics Data System (ADS)
Chen, Chang-Yuan; Lu, Fa-Lin; Sun, Dong-Sheng
2008-12-01
In this paper, using the exponential function transformation approach along with an approximation for the centrifugal potential, the radial Klein-Gordon equation with the vector and scalar Hulthén potential is transformed to a hypergeometric differential equation. The approximate analytical solutions of t-waves scattering states are presented. The normalized wave functions expressed in terms of hypergeometric functions of scattering states on the "k/2π scale" and the calculation formula of phase shifts are given. The physical meaning of the approximate analytical solution is discussed.
NASA Astrophysics Data System (ADS)
Bialynicki-Birula, Iwo
2013-03-01
General solutions of the Klein-Gordon equation satisfying the Dirichlet boundary conditions on one fixed wall and the other wall moving with a constant velocity are derived. These solutions are specified by an arbitrary periodic function whose period is equal to twice the value of the rapidity of the moving wall. Choosing this function as a combination of trigonometric functions one obtains the solutions derived recently by Koehn. The method is also tested in the case of the d'Alembert equation where it reproduces in a simple manner well-known results.
Yang, Jinxin; Guan, Yafei; Zhao, Wei; Zhou, Zhaoyu; Han, Xiaomin; Ma, Jie; Sovkov, Vladimir B; Ivanov, Valery S; Ahmed, Ergin H; Lyyra, A Marjatta; Dai, Xingcan
2016-01-14
Ro-vibrational term values of the 3(1)Σg (+) state of (85,85)Rb2 and (85,87)Rb2 and resolved fluorescence spectra to the A(1)Σu (+) state are recorded following optical-optical double resonance excitation. The experimental data are heavily perturbed, and as a result, the standard analysis based on Dunham series representation of the energy levels fails. The analysis is done via modeling the adiabatic potential function with the Rydberg-Klein-Rees potential constructed from the generalized smoothing spline interpolation of the vibrational energies Gv and rotational constants Bv. PMID:26772572
An entropic understanding of Coulomb force
NASA Astrophysics Data System (ADS)
Cho, Jin-Ho; Kim, Hyosung
2012-02-01
Exploiting Verlinde's proposal on the entropic understanding of Newton's law, we show that Coulomb force could also be understood as an entropically emergent force (rather than as a fundamental force). We apply Kaluza-Klein idea to Verlinde's formalism to obtain Coulomb interaction in the lower dimensions. The kinematics concerning the Kaluza-Klein momenta separates the interaction due to the momentum flow from the gravitational interaction. The momentum-charge conversion relation results in the precise form of Coulomb interaction.
... of clinical and basic research on diseases causing sleep disorders in an effort to clarify the mechanisms of ... Understanding Sleep Fact sheet on normal sleep and sleep disorders developed by the National Institute of Neurological Disorders ...
López, Luis I A; Yaro, Simeón Moisés; Champi, A; Ujevic, Sebastian; Mendoza, Michel
2014-02-12
We found that with an increase of the potential barrier applied to metallic graphene ribbons, the Klein tunneling current decreases until it is totally destroyed and the pseudo-spin polarization increases until it reaches its maximum value when the current is zero. This inverse relation disfavors the generation of polarized currents in a sub-lattice. In this work we discuss the pseudo-spin control (polarization and inversion) of the Klein tunneling currents, as well as the optimization of these polarized currents in a sub-lattice, using potential barriers in metallic graphene ribbons. Using density of states maps, conductance results, and pseudo-spin polarization information (all of them as a function of the energy V and width of the barrier L), we found (V, L) intervals in which the polarized currents in a given sub-lattice are maximized. We also built parallel and series configurations with these barriers in order to further optimize the polarized currents. A systematic study of these maps and barrier configurations shows that the parallel configurations are good candidates for optimization of the polarized tunneling currents through the sub-lattice. Furthermore, we discuss the possibility of using an electrostatic potential as (i) a pseudo-spin filter or (ii) a pseudo-spin inversion manipulator, i.e. a possible latticetronic of electronic currents through metallic graphene ribbons. The results of this work can be extended to graphene nanostructures. PMID:24441476
NASA Astrophysics Data System (ADS)
Rapoport, Diego L.
2011-01-01
In this transdisciplinary article which stems from philosophical considerations (that depart from phenomenology—after Merleau-Ponty, Heidegger and Rosen—and Hegelian dialectics), we develop a conception based on topological (the Moebius surface and the Klein bottle) and geometrical considerations (based on torsion and non-orientability of manifolds), and multivalued logics which we develop into a unified world conception that surmounts the Cartesian cut and Aristotelian logic. The role of torsion appears in a self-referential construction of space and time, which will be further related to the commutator of the True and False operators of matrix logic, still with a quantum superposed state related to a Moebius surface, and as the physical field at the basis of Spencer-Brown's primitive distinction in the protologic of the calculus of distinction. In this setting, paradox, self-reference, depth, time and space, higher-order non-dual logic, perception, spin and a time operator, the Klein bottle, hypernumbers due to Musès which include non-trivial square roots of ±1 and in particular non-trivial nilpotents, quantum field operators, the transformation of cognition to spin for two-state quantum systems, are found to be keenly interwoven in a world conception compatible with the philosophical approach taken for basis of this article. The Klein bottle is found not only to be the topological in-formation for self-reference and paradox whose logical counterpart in the calculus of indications are the paradoxical imaginary time waves, but also a classical-quantum transformer (Hadamard's gate in quantum computation) which is indispensable to be able to obtain a complete multivalued logical system, and still to generate the matrix extension of classical connective Boolean logic. We further find that the multivalued logic that stems from considering the paradoxical equation in the calculus of distinctions, and in particular, the imaginary solutions to this equation
NASA Astrophysics Data System (ADS)
Aggoun, L.; Benamira, F.; Guechi, L.; Sadoun, M. A.
2016-04-01
The Green's function associated with a Klein-Gordon particle moving in a D-dimensional space under the action of vector plus scalar q-deformed Hulthén potentials is constructed by path integration for {q ≥ 1} and {1/α ln q < r < infty}. An appropriate approximation of the centrifugal potential term and the technique of space-time transformation are used to reduce the path integral for the generalized Hulthén potentials into a path integral for q-deformed Rosen-Morse potential. Explicit path integration leads to the radial Green's function for any l state in closed form. The energy spectrum and the correctly normalized wave functions, for a state of orbital quantum number {l ≥ 0}, are obtained. Eventually, the vector q-deformed Hulthén potential and the Coulomb potentials in D dimensions are considered as special cases.
Reductive dissolution of goethite by phenolic reductants
NASA Astrophysics Data System (ADS)
LaKind, Judy S.; Stone, Alan T.
1989-05-01
The reductive dissolution of goethite (α-FeOOH) and hematite (α-Fe 2O 3) by phenolic reductants has been examined in order to improve the understanding of iron transformations in soils, sediments and aquifers. Rates of goethite reductive dissolution by hydroquinone increased as the pH was increased from pH 1.8 to 4.65, arid the following reaction stoichiometry was obeyed: 2 α- FeOOH + QH2 = 2 Fe2+ + Q + 4 OH-. As the pH was increased from pH 4.5 to 6.0, the reductive dissolution rate decreased to below the detection limit. At pH 3.4, the reductive dissolution of hematite was two orders of magnitude slower than goethite. The relationship between structure and reactivity was examined for a series of mono-, di-, and tri-hydroxybenzene reductants. Rates of reductive dissolution decreased in the following order: catechol ˜- hydroquinone > 3,4-dihydroxybenzoic acid > resorcinol-phenol-4-hydroxybenzoic acid.
NASA Technical Reports Server (NTRS)
Morris, R. V.; Ming, D. W.; Gellert, R.; Vaniman, D. T.; Bish, D. L.; Blake, D. F.; Chipera, S. J.; Morrison, S. M.; Downs, R. T.; Rampe, E. B.; Treiman, A. H.; Yen, A. S.; Achilles, C. N.; Archer, P. D.; Bristow, T. F.; Cavanaugh, P.; Fenrdrich, K.; Crisp, J. A.; Des Marais, D. J.; Farmer, J. D.; Grotzinger, J. P.; Mahaffy, P. R.; McAdam, A. C.; Morookian, J. M.
2015-01-01
We have previously calculated the chemical compositions of the X-ray-diffraction (XRD) amorphous component of three solid samples (Rocknest (RN) soil, John Klein (JK) drill fines, and Cumberland (CB) drill fines) using major-element chemistry (APXS), volatile-element chemistry (SAM), and crystalline- phase mineralogy (CheMin) obtained by the Curiosity rover as a part of the ongoing Mars Science Laboratory mission in Gale Crater. According to CheMin analysis, the RN and the JK and CB samples are mineralogically distinct in that RN has no detectable clay minerals and both JK and CB have significant concentrations of high-Fe saponite. The chemical composition of the XRD amorphous component is the composition remaining after mathematical removal of the compositions of crystalline components, including phyllosilicates if present. Subsequent to, we have improved the unit cell parameters for Fe-forsterite, augite, and pigeonite, resulting in revised chemical compositions for the XRD-derived crystalline component (excluding clay minerals). We update here the calculated compositions of amorphous components using these revised mineral compositions.
Papoutsoglou, Sofronios E; Karakatsouli, Nafsika; Papoutsoglou, Eustratios S; Vasilikos, Georgios
2010-09-01
The objective of this study was to further investigate the effects of music on fish physiology, bearing in mind available information regarding the involvement of endogenous and exogenous factors in fish farming. Therefore, Cyprinus carpio (50.5 +/- 0.36 g) were reared in a recirculating water system under 80 and 200 lux and subjected to no music at all (control, ambient noise only), 4 h of Mozart's "Eine Kleine Nachtmusik", or 4 h of anonymous "Romanza-Jeux Interdits" for 106 days. Both music treatments resulted in increased growth performance at both light intensities, with Romanza treatment at 200 lux resulting in better growth performance than Mozart treatment. Furthermore, feed efficiency for the Romanza groups was significantly better than for the control. Although no significant music effect was apparent for brain neurotransmitters, lower anterior intestine alkaline protease levels were detected for both music treatments. Taking into consideration the numerous advantages of recirculating water systems, it should be emphasised that fish response to music expresses the results of various physiological and biochemical processes, especially when fish notably respond differently when subjected to two different pieces of music. PMID:19408132
NASA Astrophysics Data System (ADS)
Bushnell, D. M.; Moore, K. J.
Recent studies on the drag-reducing shapes, structures, and behaviors of swimming and flying animals are reviewed, with an emphasis on potential analogs in vehicle design. Consideration is given to form drag reduction (turbulent flow, vortex generation, mass transfer, and adaptations for body-intersection regions), skin-friction drag reduction (polymers, surfactants, and bubbles as surface 'additives'), reduction of the drag due to lift, drag-reduction studies on porpoises, and drag-reducing animal behavior (e.g., leaping out of the water by porpoises). The need for further research is stressed.
NASA Technical Reports Server (NTRS)
Bushnell, D. M.; Moore, K. J.
1991-01-01
Recent studies on the drag-reducing shapes, structures, and behaviors of swimming and flying animals are reviewed, with an emphasis on potential analogs in vehicle design. Consideration is given to form drag reduction (turbulent flow, vortex generation, mass transfer, and adaptations for body-intersection regions), skin-friction drag reduction (polymers, surfactants, and bubbles as surface 'additives'), reduction of the drag due to lift, drag-reduction studies on porpoises, and drag-reducing animal behavior (e.g., leaping out of the water by porpoises). The need for further research is stressed.
Intelligent Data Reduction (IDARE)
NASA Technical Reports Server (NTRS)
Brady, D. Michael; Ford, Donnie R.
1990-01-01
A description of the Intelligent Data Reduction (IDARE) expert system and an IDARE user's manual are given. IDARE is a data reduction system with the addition of a user profile infrastructure. The system was tested on a nickel-cadmium battery testbed. Information is given on installing, loading, maintaining the IDARE system.
ERIC Educational Resources Information Center
Allaway, David
1992-01-01
Suggests that quantification is essential to establish the cost-effectiveness of source reduction (SR). Presents case studies of monitoring methods for seven different kinds of SR efforts: (1) packaging changes, (2) SR businesses, (3) waste exchanges, (4) individual nonresidential efforts, (5) variable garbage rates, (6) yard waste reduction, and…
NASA Astrophysics Data System (ADS)
Ballesteros, Miguel; Weder, Ricardo
2016-04-01
The study of obstacle scattering for the Klein-Gordon equation in the presence of long-range magnetic potentials is addressed. Previous results of the authors are extended to the long-range case and the results the authors previously proved for high-momenta long-range scattering for the Schrödinger equation are brought to the relativistic scenario. It is shown that there are important differences between relativistic and non-relativistic scattering concerning the long range. In particular, it is proven that the electric potential can be recovered without assuming the knowledge of the long-range part of the magnetic potential, which has to be supposed in the non-relativistic case. The electric potential and the magnetic field are recovered from the high-momenta limit of the scattering operator, as well as fluxes modulo 2π around the handles of the obstacle. Moreover, it is proven that for every \\hat{{v}}\\in {{{S}}}2, {A}∞ (\\hat{{v}})+{A}∞ (-\\hat{{v}}) can be reconstructed, where {A}∞ is the long-range part of the magnetic potential. A simple formula for the high-momenta limit of the scattering operator is given in terms of magnetic fluxes over handles of the obstacle and long-range magnetic fluxes at infinity, that are introduced in this paper. The appearance of these long-range magnetic fluxes is a new effect in scattering theory. Research partially supported by the project PAPIIT-DGAPA UNAM IN102215.
Footprint reduction's 'multiple paybacks'.
2010-06-01
Some of the measures that EFM personnel can take to further reduce their estates' carbon footprint at a time when pressure to cut energy consumption must be balanced both against the requirement to create the best possible patient environment, and new medical technology that may require substantial energy to operate, were the focus of a recent IHEEM carbon reduction seminar in London. The one-day event, "Planning to achieve Carbon Reduction Commitment targets for healthcare premises", also included a look at the key steps affected healthcare organisations, and especially their estates teams, need to be taking already to ensure compliance with the new Carbon Reduction Commitment scheme. PMID:20597381
NASA Technical Reports Server (NTRS)
Bingham, Cindy
1990-01-01
Viewgraphs on reduction of bone strength are presented. WEHI 231 B growth rates, experimental chambers used to apply the electric field to the cell cultures, and a mouse suspended by rotating cuff in electromagnetic field are shown.
This is the first phase of a potentially multi-phase project aimed at identifying scientific methodologies that will lead to the development of innnovative analytical tools supporting the analysis of control strategy effectiveness, namely. accountabilty. Significant reductions i...
3D supergravity from wrapped M5-branes
NASA Astrophysics Data System (ADS)
Karndumri, Parinya; Ó Colgáin, Eoin
2016-03-01
Through consistent Kaluza-Klein reduction, we construct 3D N=2 gauged supergravities corresponding to twisted compactifications of M5-branes on a product of constant curvature Riemann surfaces, including Kähler-Einstein four-manifolds. We extend the reduction to fermionic supersymmetry variations in order to determine the 3D Killing spinor equations and classify all timelike supersymmetric solutions. As a by-product, we identify an infinite class of new supersymmetric warped AdS 3 (Gödel) and warped dS 3 solutions. Moreover, we show that the superpotential T encodes the central charge and R symmetry of the dual N=(0,2) SCFTs in the large N limit. We demonstrate that the R symmetry matches the canonical U(1) isometry from existing classifications of supersymmetric AdS 3 solutions to 11D supergravity with N=(0,2) supersymmetry.
REDUCTIONS WITHOUT REGRET: SUMMARY
Swegle, J.; Tincher, D.
2013-09-16
This paper briefly summarizes the series in which we consider the possibilities for losing, or compromising, key capabilities of the U.S. nuclear force in the face of modernization and reductions. The first of the three papers takes an historical perspective, considering capabilities that were eliminated in past force reductions. The second paper is our attempt to define the needed capabilities looking forward in the context of the current framework for force modernization and the current picture of the evolving challenges of deterrence and assurance. The third paper then provides an example for each of our undesirable outcomes: the creation of roach motels, box canyons, and wrong turns.
Discrete reductive perturbation technique
Levi, Decio; Petrera, Matteo
2006-04-15
We expand a partial difference equation (P{delta}E) on multiple lattices and obtain the P{delta}E which governs its far field behavior. The perturbative-reductive approach is here performed on well-known nonlinear P{delta}Es, both integrable and nonintegrable. We study the cases of the lattice modified Korteweg-de Vries (mKdV) equation, the Hietarinta equation, the lattice Volterra-Kac-Van Moerbeke equation and a nonintegrable lattice KdV equation. Such reductions allow us to obtain many new P{delta}Es of the nonlinear Schroedinger type.
Straub, Heather; Qadir, Sameen; Miller, Greg; Borders, Ann
2014-09-01
Chronic stress contributes to preterm birth (PTB), through direct physiological mechanisms or behavioral pathways. This review identified interventions to prevent PTB through decreased maternal stress. Studies were grouped according to intervention: group prenatal care (11 studies), care coordination (8 studies), health insurance expansion (4 studies), expanded prenatal education/support in the clinic (8 studies), home visitation (9 studies), telephone contact (2 studies), or stress-reduction strategies (5 studies). Group prenatal care had the most evidence for PTB prevention. Comparative studies of PTB prevention through different models of prenatal care and maternal support, education, empowerment, stress-reduction, and coping strategies are needed. PMID:24979355
NASA Astrophysics Data System (ADS)
Ernst, Gerhard; Hüttemann, Andreas
2010-01-01
List of contributors; 1. Introduction Gerhard Ernst and Andreas Hütteman; Part I. The Arrows of Time: 2. Does a low-entropy constraint prevent us from influencing the past? Mathias Frisch; 3. The part hypothesis meets gravity Craig Callender; 4. Quantum gravity and the arrow of time Claus Kiefer; Part II. Probability and Chance: 5. The natural-range conception of probability Jacob Rosenthal; 6. Probability in Boltzmannian statistical mechanics Roman Frigg; 7. Humean mechanics versus a metaphysics of powers Michael Esfeld; Part III. Reduction: 8. The crystallisation of Clausius's phenomenological thermodynamics C. Ulises Moulines; 9. Reduction and renormalization Robert W. Batterman; 10. Irreversibility in stochastic dynamics Jos Uffink; Index.
Greybody factors for Myers–Perry black holes
Boonserm, Petarpa; Chatrabhuti, Auttakit Ngampitipan, Tritos; Visser, Matt
2014-11-15
The Myers–Perry black holes are higher-dimensional generalizations of the usual (3+1)-dimensional rotating Kerr black hole. They are of considerable interest in Kaluza–Klein models, specifically within the context of brane-world versions thereof. In the present article, we shall consider the greybody factors associated with scalar field excitations of the Myers–Perry spacetimes, and develop some rigorous bounds on these greybody factors. These bounds are of relevance for characterizing both the higher-dimensional Hawking radiation, and the super-radiance, that is expected for these spacetimes.
ERIC Educational Resources Information Center
Clarke, H. Harrison, Ed.
1975-01-01
This document analyzes the problems encountered by the obese individual and the effects of regular exercise on weight loss and fat reduction. Part one compares the psychological traits of obese children with age groups of normal weight and discusses the organic disorders and social attitudes which plague the overweight individual. Part two states…
Hadamard speckle contrast reduction
NASA Astrophysics Data System (ADS)
Trisnadi, Jahja I.
2004-01-01
The condition for a diffuser to produce the maximum speckle contrast reduction with the minimum number of distinct phase patterns is derived. A binary realization of this optimum diffuser is obtained by mapping the rows or columns of a Hadamard matrix to the phase patterns. The method is experimentally verified in the Grating Light Valve laser projection display.
Industrial Waste Reduction Program
Not Available
1991-10-24
US industry generates over 12 billion tons of wastes each year. These wastes consist of undesirable by-products of industrial production that are discarded into our environment. Energy is an integral part of these wastes; it is found in the embodied energy of industrial feedstocks not optimally used, in the energy content of the wastes themselves, and in the energy needed to transport, treat, and dispose of wastes. Estimates of the potential energy savings from reducing industrial wastes range from three to four quadrillion Btu per year -- enough to meet the annual energy needs of 30 million American homes. This document presents a plan for the Industrial Waste Reduction Program, which has been designed to help achieve national goals for energy efficiency and waste minimization. The objective of the program is to improve the energy efficiency of industrial processes through cost-effective waste reduction. The initial program focus is on waste reduction opportunities in the production and use of chemicals, due to the significant amount of energy used in these activities and the large amounts of hazardous and toxic wastes they generate. The chemical industry will be the initial subject of a series of waste reduction opportunity assessments conducted as part of the program. Assessments of other industries and waste problems will follow.
ERIC Educational Resources Information Center
Wood, R. Craig
This chapter of "Principles of School Business Management" reviews several concerns that must be addressed by school business administrators in districts facing declining enrollments and the need for reductions in force. The chapter first looks at the business administrator's significant role in planning for retrenchment. The chapter then…
ERIC Educational Resources Information Center
Phay, Robert
Chapter 2 in a book on school law discusses the reasons for reduction in force (RIF) and presents a set of model regulations for school districts as the best means of minimizing legal problems resulting from RIF. The reasons for RIF include declining student enrollments; reduced turnover among teachers; changes in programs; and more constrained…
Adolescent Prejudice Reduction Conference.
ERIC Educational Resources Information Center
Ketroser, Heidi
1988-01-01
Discusses the fifth annual Dr. Curtis C. Melnick Adolescent Prejudice Reduction Conference sponsored by the Greater Chicago (Illinois) Regional Office of the Anti-Defamation League of the B'nai B'rith. The day-long conference addressed issues of prejudice and allowed students and staff from various high schools to explore their concerns with…
Imino Transfer Hydrogenation Reductions.
Wills, Martin
2016-04-01
This review contains a summary of recent developments in the transfer hydrogenation of C=N bonds, with a particularly focus on reports from within the last 10 years and asymmetric transformations. However, earlier work in the area is also discussed in order to provide context for the more recent results described. I focus strongly on the Ru/TsDPEN class of asymmetric transfer hydrogenation reactions originally reported by Noyori et al., together with examples of their applications, particularly to medically valuable target molecules. The recent developments in the area of highly active imine-reduction catalysts, notably those based on iridium, are also described in some detail. I discuss diastereoselective reduction methods as a route to the synthesis of chiral amines using transfer hydrogenation. The recent development of a methodology for positioning reduction complexes within chiral proteins, permitting the generation of asymmetric reduction products through a directed modification of the protein environment in a controlled manner, is also discussed. PMID:27573139
Sarkar, Sahotra
2015-10-01
This paper attempts a critical reappraisal of Nagel's (1961, 1970) model of reduction taking into account both traditional criticisms and recent defenses. This model treats reduction as a type of explanation in which a reduced theory is explained by a reducing theory after their relevant representational items have been suitably connected. In accordance with the deductive-nomological model, the explanation is supposed to consist of a logical deduction. Nagel was a pluralist about both the logical form of the connections between the reduced and reducing theories (which could be conditionals or biconditionals) and their epistemological status (as analytic connections, conventions, or synthetic claims). This paper defends Nagel's pluralism on both counts and, in the process, argues that the multiple realizability objection to reductionism is misplaced. It also argues that the Nagel model correctly characterizes reduction as a type of explanation. However, it notes that logical deduction must be replaced by a broader class of inferential techniques that allow for different types of approximation. Whereas Nagel (1970), in contrast to his earlier position (1961), recognized the relevance of approximation, he did not realize its full import for the model. Throughout the paper two case studies are used to illustrate the arguments: the putative reduction of classical thermodynamics to the kinetic theory of matter and that of classical genetics to molecular biology. PMID:26386529
Financing Class Size Reduction
ERIC Educational Resources Information Center
Achilles, C. M.
2005-01-01
Class size reduction has been shown to, among other things, improve academic achievement for all students and particularly for low-income and minority students. With the No Child Left Behind Act's heavy emphasis on scientifically based research, adequate yearly progress, and disaggregated results, one wonders why all children aren't enrolled in…
ERIC Educational Resources Information Center
Armoni, Michal; Gal-Ezer, Judith
2005-01-01
When dealing with a complex problem, solving it by reduction to simpler problems, or problems for which the solution is already known, is a common method in mathematics and other scientific disciplines, as in computer science and, specifically, in the field of computability. However, when teaching computational models (as part of computability)…
Static axisymmetric solutions with electric fields in low-energy string theory
NASA Astrophysics Data System (ADS)
Wei, Yi-Huan; Zhang, Yuan-Zhong; He, Feng
2002-12-01
In this paper, we prove that all five-dimensional axisymmetric Kaluza-Klein spacetime solutions with electrostatic fields may also be those of low-energy string theory. From the class of TS-like solutions in Kaluza-Klein theory we obtain the corresponding class of solutions with electric dipoles in low-energy string theory, which are enlarged to solutions with electric charges under the SO(1, 1) transformation. We obtain the complete metric for the TS-like solution with δ = 1. Lastly, we give a discussion.
Carroll, Sean M.; Tam, Heywood
2008-08-15
We propose a new way to hide large extra dimensions without invoking branes, based on Lorentz-violating tensor fields with expectation values along the extra directions. We investigate the case of a single vector aether field on a compact circle. In such a background, interactions of other fields with the aether can lead to modified dispersion relations, increasing the mass of the Kaluza-Klein excitations. The mass scale characterizing each Kaluza-Klein tower can be chosen independently for each species of scalar, fermion, or gauge boson. No small-scale deviations from the inverse square law for gravity are predicted, although light graviton modes may exist.
New instabilities of de Sitter spacetimes
Copsey, Keith; Mann, Robert
2010-04-15
We construct an instanton describing the pair production of non-Kaluza-Klein bubbles of nothing in higher odd-dimensional de Sitter spaces. In addition to showing that higher-dimensional de Sitter spaces have a nonzero probability to become topologically nontrivial, this process provides direct evidence for the association of entropy with cosmological horizons as well as evidence that non-Kaluza-Klein bubbles of nothing are a necessary ingredient in string theory or any other consistent quantum theory of gravity in higher dimensions.
Reduction/Transformation Operators
Bartlett, Roscoe A.
2006-09-01
RTOp (reduction/transformation operators) is a collection of C++ software that provides the basic mechanism for implementinig vector operations in a flexible and efficient manner. This is the main interface utilized by Thyra to allow for the specification of specific vector reduction and/or transformation operations. The RTOp package contains three different types of software. (a) a small number of interoperability interfaces. (b) support software including code for the parallel SPMD mode based on only Teuchos::Comm(and not MPl directly(, and (c) a library of pre-implemented RTOp subclasses for everything from simple AXPYs and norms, to more specialized vector operations. RTOp allows an algorithm developer to implement their own RTOp subclasses in a way that is independent from any specific serial, parallel, out-of-core or other type of vector implementation. RTOp is a required package by Thyra and MOOCHO. (c)
Bacterial reduction of chromium
Schmieman, E.A.; Yonge, D.R.; Johnstone, D.L.
1997-12-31
A mixed culture was enriched from surface soil obtained from an eastern United States site highly contaminated with chromate. Growth of the culture was inhibited by a chromium concentration of 12 mg/L. Another mixed culture was enriched from subsurface soil obtained from the Hanford reservation, at the fringe of a chromate plume. The enrichment medium was minimal salts solution augmented with acetate as the carbon source, nitrate as the terminal electron acceptor, and various levels of chromate. This mixed culture exhibited chromate tolerance, but not chromate reduction capability, when growing anaerobically on this medium. However, this culture did exhibit chromate reduction capability when growing anaerobically on TSB. Growth of this culture was not inhibited by a chromium concentration of 12 mg/L. Mixed cultures exhibited decreasing diversity with increasing levels of chromate in the enrichment medium. An in situ bioremediation strategy is suggested for chromate contaminated soil and groundwater. 16 refs., 5 figs., 1 tab.
Reduction/Transformation Operators
2006-09-01
RTOp (reduction/transformation operators) is a collection of C++ software that provides the basic mechanism for implementinig vector operations in a flexible and efficient manner. This is the main interface utilized by Thyra to allow for the specification of specific vector reduction and/or transformation operations. The RTOp package contains three different types of software. (a) a small number of interoperability interfaces. (b) support software including code for the parallel SPMD mode based on only Teuchos::Comm(and notmore » MPl directly(, and (c) a library of pre-implemented RTOp subclasses for everything from simple AXPYs and norms, to more specialized vector operations. RTOp allows an algorithm developer to implement their own RTOp subclasses in a way that is independent from any specific serial, parallel, out-of-core or other type of vector implementation. RTOp is a required package by Thyra and MOOCHO. (c)« less
Griffing, Bill; /Fermilab
2005-06-01
In a recent DOE Program Review, Fermilab's director presented results of the laboratory's effort to reduce the injury rate over the last decade. The results, shown in the figure below, reveal a consistent and dramatic downward trend in OSHA recordable injuries at Fermilab. The High Energy Physics Program Office has asked Fermilab to report in detail on how the laboratory has achieved the reduction. In fact, the reduction in the injury rate reflects a change in safety culture at Fermilab, which has evolved slowly over this period, due to a series of events, both planned and unplanned. This paper attempts to describe those significant events and analyze how each of them has shaped the safety culture that, in turn, has reduced the rate of injury at Fermilab to its current value.
Aluminum reduction cell electrode
Goodnow, Warren H.; Payne, John R.
1982-01-01
The invention is directed to cathode modules comprised of refractory hard metal materials, such as TiB.sub.2, for an electrolytic cell for the reduction of alumina wherein the modules may be installed and replaced during operation of the cell and wherein the structure of the cathode modules is such that the refractory hard metal materials are not subjected to externally applied forces or rigid constraints.
Television noise reduction device
NASA Technical Reports Server (NTRS)
Gordon, B. L.; Stamps, J. C. (Inventor)
1975-01-01
A noise reduction system that divides the color video signal into its luminance and chrominance components is reported. The luminance component of a given frame is summed with the luminance component of at least one preceding frame which was stored on a disc recorder. The summation is carried out so as to achieve a signal amplitude equivalent to that of the original signal. The averaged luminance signal is then recombined with the chrominance signal to achieve a noise-reduced television signal.
[Aware and cooperative reduction].
Tambone, V; Ghilardi, G
2012-01-01
The aim of this work is to address the question of reduction in the scientific method, to evaluate its legitimacy as well as its pro and contra from an epistemological point of view. In the first paragraph we classify some kinds of reductionism, analysing their presuppositions and epistemological status and showing some examples of scientific reduction. The presentation includes a classificatory table that shows some of the different forms of biological reductionism. In the second paragraph we study the epistemology of science starting from its modern beginning: the Vienna Circle, focusing on the meaning of methodological reductionism. What did it mean for science to define itself mainly as method, which effects did this new concept of science have on methodology and what kind of problems did this movement bring about. In the third paragraph we examine the reactions triggered by methodological reductionism, we analyze the theoretical consistency of these answers, trying to offer a balanced view. We show how complexity can be seen as a paradigm of the anti-reductionism effort, and we study its epistemological basis. In the fourth paragraph we outline our operative proposal: the reduction that is both aware and cooperative. We point out the main reasons why science cannot avoid being reductive in some way, and therefore how we need to deal with this feature in order to prevent it to degenerate into reductionism. We show some examples of this new proposal taken from the practical realm and from literature, where it is possible to discern the spirit of this alternative methodology. PMID:22964706
NASA Technical Reports Server (NTRS)
Hill, D. Christopher
1994-01-01
previously a description was given of an active control scheme using wall transpiration that leads to a 15% reduction in surface skin friction beneath a turbulent boundary layer, according to direct numerical simulation. In this research brief further details of that scheme and its variants are given together with some suggestions as to how sensor/actuator arrays could be configured to reduce surface drag. The research which is summarized here was performed during the first half of 1994. This research is motivated by the need to understand better how the dynamics of near-wall turbulent flow can be modified so that skin friction is reduced. The reduction of turbulent skin friction is highly desirable in many engineering applications. Experiments and direct numerical simulations have led to an increased understanding of the cycle of turbulence production and transport in the boundary layer and raised awareness of the possibility of disrupting the process with a subsequent reduction in turbulent skin friction. The implementation of active feedback control in a computational setting is a viable approach for the investigation of the modifications to the flow physics that can be achieved. Bewley et al. and Hill describe how ideas from optimal control theory are employed to give 'sub-optimal' drag reduction schemes. The objectives of the work reported here is to investigate in greater detail the assumptions implicit within such schemes and their limitations. It is also our objective to describe how an array of sensors and actuators could be arranged and interconnected to form a 'smart' surface which has low skin friction.
Aluminum reduction cell electrode
Goodnow, W.H.; Payne, J.R.
1982-09-14
The invention is directed to cathode modules comprised of refractory hard metal materials, such as TiB[sub 2], for an electrolytic cell for the reduction of alumina wherein the modules may be installed and replaced during operation of the cell and wherein the structure of the cathode modules is such that the refractory hard metal materials are not subjected to externally applied forces or rigid constraints. 9 figs.
Reduction of astrographic catalogues
NASA Technical Reports Server (NTRS)
Stock, J.; Prugna, F. D.; Cova, J.
1984-01-01
An automatic program for the reduction of overlapping Carte du Ciel plates is described. The projection and transformation equations are given and the RAA subprogram flow is outlined. The program was applied to two different sets of data, namely to nine overlapping plates of the Cape Zone of the CdC, and to fifteen plates taken with the CIDA-refractor of the open cluster Tr10.
Echocardiographic speckle reduction comparison.
Finn, Seán; Glavin, Martin; Jones, Edward
2011-01-01
In this paper, a detailed description and comparison of speckle reduction of medical ultrasound, and in particular echocardiography, is presented. Fifteen speckle reduction filters are described in a detailed fashion to facilitate implementation for research and evaluation. The filtering techniques considered include anisotropic diffusion, wavelet denoising, and local statistics. Common nomenclature and notation are adopted, to expedite comparison between approaches. Comparison of the filters is based on their application to simulated images, clinical videos, and a computational requirement analysis. The ultrasound simulation method provides a realistic model of the image acquisition process, and permits the use of a noise-free reference image for comparison. Application of objective quality metrics quantifies the preservation of image edges, overall image distortion, and improvement in image contrast. The computational analysis quantifies the number of operations required for each speckle reduction method. A speed-accuracy analysis of discretization methods for anisotropic diffusion is included. It is concluded that the optimal method is the OSRAD diffusion filter. This method is capable of strong speckle suppression, increasing the average SNRA of the simulated images by a factor of two. This method also shows favorable edge preservation and contrast improvement, and may be efficiently implemented. PMID:21244977
Phase transitions of an anisotropic N=4 super Yang-Mills plasma via holography
NASA Astrophysics Data System (ADS)
Banks, Elliot
2016-07-01
Black hole solutions of type IIB supergravity were previously found that are dual to N=4 supersymmetric Yang-Mills plasma with an anisotropic spatial deformation. In the zero temperature limit, these black holes approach a Liftshitz like scaling solution in the IR. It was recently shown that these black holes are unstable, and at low temperatures there is a new class of black hole solutions that are thermodynamically preferred. We extend this analysis, by considering consistent truncations of the Kaluza-Klein reduction of IIB supergravity on a five-sphere that preserves multiple scalar and U(1) gauge fields. We show that the previously constructed black holes become unstable at low temperatures, and construct new classes of exotic black hole solutions. We study the DC thermo-electric conductivity of these U(1) charged black holes, and find a diverging DC conductivity at zero temperature due to the divergence of the gauge field coupling.
Quantum (in)stability of 2D charged dilaton black holes and 3D rotating black holes
NASA Astrophysics Data System (ADS)
Nojiri, Shin'ichi; Odintsov, Sergei D.
1999-02-01
The quantum properties of charged black holes (BHs) in two-dimensional (2D) dilaton-Maxwell gravity (spontaneously compactified from heterotic string) with N dilaton coupled scalars are studied. We first investigate 2D BHs found by McGuigan, Nappi, and Yost. Kaluza-Klein reduction of 3D gravity with minimal scalars leads also to 2D dilaton-Maxwell gravity with dilaton coupled scalars and the rotating BH solution found by Bañados, Teitelboim, and Zanelli, which can be also described by 2D charged dilatonic BHs. Evaluating the one-loop effective action for dilaton coupled scalars in large N (and the s-wave approximation for the Bañados-Teitelboim-Zanelli case), we show that quantum-corrected BHs may evaporate or else antievaporate similarly to 4D Nariai BHs as is observed by Bousso and Hawking. Higher modes may cause the disintegration of BHs in accordance with recent observation by Bousso.
Generalised Eisenhart lift of the Toda chain
Cariglia, Marco; Gibbons, Gary
2014-02-15
The Toda chain of nearest neighbour interacting particles on a line can be described both in terms of geodesic motion on a manifold with one extra dimension, the Eisenhart lift, or in terms of geodesic motion in a symmetric space with several extra dimensions. We examine the relationship between these two realisations and discover that the symmetric space is a generalised, multi-particle Eisenhart lift of the original problem that reduces to the standard Eisenhart lift. Such generalised Eisenhart lift acts as an inverse Kaluza-Klein reduction, promoting coupling constants to momenta in higher dimension. In particular, isometries of the generalised lift metric correspond to energy preserving transformations that mix coordinates and coupling constants. A by-product of the analysis is that the lift of the Toda Lax pair can be used to construct higher rank Killing tensors for both the standard and generalised lift metrics.
NASA Astrophysics Data System (ADS)
Furuuchi, Kazuyuki
2016-07-01
In this article we study Kaluza-Klein (KK) dimensional reduction of massive Abelian gauge theories with charged matter fields on a circle. Since local gauge transformations change position dependence of the charged fields, the decomposition of the charged matter fields into KK modes is gauge dependent. While whole KK mass spectrum is independent of the gauge choice, the mode number depends on the gauge. The masses of the KK modes also depend on the field value of the zero-mode of the extra dimensional component of the gauge field. In particular, one of the KK modes in the KK tower of each massless 5D charged field becomes massless at particular values of the extra-dimensional component of the gauge field. When the extra-dimensional component of the gauge field is identified with the inflaton, this structure leads to recursive cosmological particle productions.
Reduction of turbomachinery noise
NASA Technical Reports Server (NTRS)
Waitz, Ian A. (Inventor); Brookfield, John M. (Inventor); Sell, Julian (Inventor); Hayden, Belva J. (Inventor); Ingard, K. Uno (Inventor)
1999-01-01
In the invention, propagating broad band and tonal acoustic components of noise characteristic of interaction of a turbomachine blade wake, produced by a turbomachine blade as the blade rotates, with a turbomachine component downstream of the rotating blade, are reduced. This is accomplished by injection of fluid into the blade wake through a port in the rotor blade. The mass flow rate of the fluid injected into the blade wake is selected to reduce the momentum deficit of the wake to correspondingly increase the time-mean velocity of the wake and decrease the turbulent velocity fluctuations of the wake. With this fluid injection, reduction of both propagating broad band and tonal acoustic components of noise produced by interaction of the blade wake with a turbomachine component downstream of the rotating blade is achieved. In a further noise reduction technique, boundary layer fluid is suctioned into the turbomachine blade through a suction port on the side of the blade that is characterized as the relatively low-pressure blade side. As with the fluid injection technique, the mass flow rate of the fluid suctioned into the blade is here selected to reduce the momentum deficit of the wake to correspondingly increase the time-mean velocity of the wake and decrease the turbulent velocity fluctuations of the wake; reduction of both propagating broad band and tonal acoustic components of noise produced by interaction of the blade wake with a turbomachine component downstream of the rotating blade is achieved with this suction technique. Blowing and suction techniques are also provided in the invention for reducing noise associated with the wake produced by fluid flow around a stationary blade upstream of a rotating turbomachine.
Dimensional reduction transition
Kolb, E.
1984-11-01
In this conference on phase transitions in the early Universe the author discusses the transition from more than four space-time dimensions to four effective space-time dimensions; the dimensional reduction transition. The basic assumption is that the true dimensionality of space-time is more than four, and that at present the extra dimensions are compact and too small to be observable. The origin of the observed gauge symmetries from symmetries of a compact space has been proposed as a possible approach for the unification of particle physics and gravity. The common assumption in all models with extra dimensions is that the unseen dimensions are compactified to a very small size, usually taken to be of the order of the Planck length. To probe the structure of the extra dimensions would require energies of the Planck mass E = m/sub pl/ = 1.2 x 10/sup 19/GeV, and the early Universe may be the only source of such energies. The author will assume for initial conditions that all spatial dimensions are small, and that initially the Universe had N = 3 + D spatial dimensions. When the temperature fell below T = R/sub D//sup -1/, where R/sub D/ is the physical size of the compact extra dimensions, the space-time dimensionality of the Universe underwent a reduction to effectively a 4 space-time dimensional Universe, and dynamical effects of the extra dimensions became unimportant. In this paper I will discuss three possible consequences of this cosmological dimensional reduction; entropy production (inflation), magnetic monopole production, and stable, massive particle production. 14 refs., 4 figs.
Electrolytic oxide reduction system
Wiedmeyer, Stanley G; Barnes, Laurel A; Williamson, Mark A; Willit, James L; Berger, John F
2015-04-28
An electrolytic oxide reduction system according to a non-limiting embodiment of the present invention may include a plurality of anode assemblies, a plurality of cathode assemblies, and a lift system configured to engage the anode and cathode assemblies. The cathode assemblies may be alternately arranged with the anode assemblies such that each cathode assembly is flanked by two anode assemblies. The lift system may be configured to selectively engage the anode and cathode assemblies so as to allow the simultaneous lifting of any combination of the anode and cathode assemblies (whether adjacent or non-adjacent).
REDSPEC: NIRSPEC data reduction
NASA Astrophysics Data System (ADS)
Kim, S.; Prato, L.; McLean, I.
2015-07-01
REDSPEC is an IDL based reduction package designed with NIRSPEC in mind though can be used to reduce data from other spectrographs as well. REDSPEC accomplishes spatial rectification by summing an A+B pair of a calibration star to produce an image with two spectra; the image is remapped on the basis of polynomial fits to the spectral traces and calculation of gaussian centroids to define their separation, producing straight spectral traces with respect to the detector rows. The raw images are remapped onto a coordinate system with uniform intervals in spatial extent along the slit and in wavelength along the dispersion axis.
Aluminum reduction cell electrode
Payne, John R.
1983-09-20
The invention is directed to an anode-cathode structure for an electrolytic cell for the reduction of alumina wherein the structure is comprised of a carbon anode assembly which straddles a wedge-shaped refractory hard metal cathode assembly having steeply sloped cathodic surfaces, each cathodic surface being paired in essentially parallel planar relationship with an anode surface. The anode-cathode structure not only takes into account the structural weakness of refractory hard metal materials but also permits the changing of the RHM assembly during operation of the cell. Further, the anode-cathode structure enhances the removal of anode gas from the interpolar gap between the anode and cathode surfaces.
Tabereaux, A.T.; Gunnip, F.L.
1987-06-16
An alumina reduction cell is described having a cathode and an anode. The anode is formed of a carbonaceous paste and baked during operation of cell and the anode having rows of anode pins on opposing faces. The pins are positioned by passing the pins through openings in anode channels vertically stacked along the opposing faces of the anode. The lowermost row of anode pins carries current through the anode; the improvement positions the anode pins passing through along a line of constant current distribution in the anode.
Aircraft engine pollution reduction
NASA Technical Reports Server (NTRS)
Rudey, R. A.
1972-01-01
The effect of engine operation on the types and levels of the major aircraft engine pollutants is described and the major factors governing the formation of these pollutants during the burning of hydrocarbon fuel are discussed. Methods which are being explored to reduce these pollutants are discussed and their application to several experimental research programs are pointed out. Results showing significant reductions in the levels of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen obtained from experimental combustion research programs are presented and discussed to point out potential application to aircraft engines.
Assi, Berthe; Yapo-Ehounoud, Constance; Baby, Mohamed Ben Allaoui; Aka-Diarra, Evelyne; Amon-Tanoh, Muriel; Tanoh, Christian
2016-01-01
The Kleine-Levin syndrome is a rare pathology characterized by recurrent episodes of hypersomnia associated with behavioral and cognitive disorders with, among others, hyperphagia and hypersexuality. The disease mainly affects young males. A few studies mention cases that occurred in Africa, especially in Côte d'Ivoire. In this paper, we report the very first two cases observed in the Neurology Department of the University Hospital of Cocody. The diagnosis was clinical, based on the recurrence of hypersomnia, cognitive and behavioral disorders during the periods of hypersomnia, and the return of patients to normal state between episodes. This diagnosis was delayed due to failure to understand the pathology, thereby leading patients to wandering. In fact, the two patients were consulted, respectively, 3 years and 6 years after the hypersomnia began. The objective was to report the very first cases observed in the Neurology Department of the University Hospital of Cocody, Côte d'Ivoire. PMID:26989535
NASA Technical Reports Server (NTRS)
Hultgren, Lennart S.
2011-01-01
This presentation is a technical summary of and outlook for NASA-internal and NASA-sponsored external research on core (combustor and turbine) noise funded by the Fundamental Aeronautics Program Subsonic Fixed Wing (SFW) Project. Sections of the presentation cover: the SFW system-level noise metrics for the 2015, 2020, and 2025 timeframes; turbofan design trends and their aeroacoustic implications; the emerging importance of core noise and its relevance to the SFW Reduce-Perceived-Noise Technical Challenge; and the current research activities in the core noise area. Recent work1 on the turbine-transmission loss of combustor noise is briefly described, two2,3 new NRA efforts in the core-noise area are outlined, and an effort to develop CMC-based acoustic liners for broadband noise reduction suitable for turbofan-core application is delineated. The NASA Fundamental Aeronautics Program has the principal objective of overcoming today's national challenges in air transportation. The reduction of aircraft noise is critical to enabling the anticipated large increase in future air traffic. The Subsonic Fixed Wing Project's Reduce-Perceived-Noise Technical Challenge aims to develop concepts and technologies to dramatically reduce the perceived aircraft noise outside of airport boundaries.
Finch, Charlie T.; Zacharias, Norbert; Wycoff, Gary L.
2010-06-15
Presented here are the details of the astrometric reductions from the x, y data to mean right ascension (R.A.), declination (decl.) coordinates of the third U.S. Naval Observatory CCD Astrograph Catalog (UCAC3). For these new reductions we used over 216,000 CCD exposures. The Two-Micron All-Sky Survey (2MASS) data are used extensively to probe for coordinate and coma-like systematic errors in UCAC data mainly caused by the poor charge transfer efficiency of the 4K CCD. Errors up to about 200 mas have been corrected using complex look-up tables handling multiple dependences derived from the residuals. Similarly, field distortions and sub-pixel phase errors have also been evaluated using the residuals with respect to 2MASS. The overall magnitude equation is derived from UCAC calibration field observations alone, independent of external catalogs. Systematic errors of positions at the UCAC observing epoch as presented in UCAC3 are better corrected than in the previous catalogs for most stars. The Tycho-2 catalog is used to obtain final positions on the International Celestial Reference Frame. Residuals of the Tycho-2 reference stars show a small magnitude equation (depending on declination zone) that might be inherent in the Tycho-2 catalog.
Councell, T.B.; Landa, E.R.; Lovley, D.R.
1997-01-01
The different oxidation species of iodine have markedly different sorption properties. Hence, changes in iodine redox states can greatly affect the mobility of iodine in the environment. Although a major microbial role has been suggested in the past to account for these redox changes, little has been done to elucidate the responsible microorganisms or the mechanisms involved. In the work presented here, direct microbial reduction of iodate was demonstrated with anaerobic cell suspensions of the sulfate reducing bacterium Desulfovibrio desulfuricans which reduced 96% of an initial 100 ??M iodate to iodide at pH 7 in 30 mM NaHCO3 buffer, whereas anaerobic cell suspensions of the dissimilatory Fe(III)-reducing bacterium Shewanella putrefaciens were unable to reduce iodate in 30 mM NaHCO3 buffer (pH 7). Both D. desulfuricans and S. putrefaciens were able to reduce iodate at pH 7 in 10 mM HEPES buffer. Both soluble ferrous iron and sulfide, as well as iron monosulfide (FeS) were shown to abiologically reduce iodate to iodide. These results indicate that ferric iron and/or sulfate reducing bacteria are capable of mediating both direct, enzymatic, as well as abiotic reduction of iodate in natural anaerobic environments. These microbially mediated reactions may be important factors in the fate and transport of 129I in natural systems.
Reductant injection and mixing system
Reeves, Matt; Henry, Cary A.; Ruth, Michael J.
2016-02-16
A gaseous reductant injection and mixing system is described herein. The system includes an injector for injecting a gaseous reductant into an exhaust gas stream, and a mixer attached to a surface of the injector. The injector includes a plurality of apertures through which the gaseous reductant is injected into an exhaust gas stream. The mixer includes a plurality of fluid deflecting elements.
Aluminum reduction cell electrode
Payne, J.R.
1983-09-20
The invention is directed to an anode-cathode structure for an electrolytic cell for the reduction of alumina wherein the structure is comprised of a carbon anode assembly which straddles a wedge-shaped refractory hard metal cathode assembly having steeply sloped cathodic surfaces, each cathodic surface being paired in essentially parallel planar relationship with an anode surface. The anode-cathode structure not only takes into account the structural weakness of refractory hard metal materials but also permits the changing of the RHM assembly during operation of the cell. Further, the anode-cathode structure enhances the removal of anode gas from the interpolar gap between the anode and cathode surfaces. 10 figs.
Aircraft engine pollution reduction.
NASA Technical Reports Server (NTRS)
Rudey, R. A.
1972-01-01
The effect of engine operation on the types and levels of the major aircraft engine pollutants is described and the major factors governing the formation of these pollutants during the burning of hydrocarbon fuel are discussed. Methods which are being explored to reduce these pollutants are discussed and their application to several experimental research programs are pointed out. Results showing significant reductions in the levels of carbon monoxide, unburned hydrocarbons, and oxides of nitrogen obtained from experimental combustion research programs are presented and discussed to point out potential application to aircraft engines. An experimental program designed to develop and demonstrate these and other advanced, low pollution combustor design methods is described. Results that have been obtained to date indicate considerable promise for reducing advanced engine exhaust pollutants to levels significantly below current engines.
Secondary superheater slagging reduction
Larose, J.A. ); Benson, R.C. )
1992-01-01
Utility boilers can be modified to reduce excessive slagging on the secondary superheater lower leading edges. Reduction of the high slagging accumulation rates will increase the pendant heat absorption and reduce the required superheater cleaning and slag removal. The cause of te slagging and appropriate boiler modifications are determined with numerical modeling. Results from two utility boiler analyses showed that regions of high gas and particle temperatures and flow rates exist near the superheater lower surfaces and are the probable cause of the rapid slagging. Design modifications which redistribute the flow and reduce the temperature entering the superheater reduce the impaction of molten ash on the pendant surface; this lowers the slag accumulation rate which allows the boiler to operate longer without cleaning and at a higher capacity. This paper shows the potential improvements in the secondary superheater inlet conditions by modifying the boiler.
Reductive electrolytic dechlorination
Norton, J.W. Jr.; Suidan, M.T.; Venosa, A.D.; Acheson, C.M.
1995-11-01
A biofilm-electrode reactor (BER) was used to dechlorinate pentachlorophenol (PCP), a recalcitrant halogenated organic used in wood and leather preservation. Electrical current was shown to play a necessary role in dechlorination, although it is unknown whether this was due to the resultant generation of hydrogen or the low reducing potential surface formed on the cathode of the anode-cathode cell. The PCP concentration in the feed was 5,000 {micro} g/L, and the PCP in the effluent was about 50 {micro}g/L, at a ethanol feed of 5 mg/L, which is a 99% reduction in PCP concentration. The feed ethanol was varied from zero to 100 mg/L, with the greatest PCP removal occurring at the highest ethanol feed rate. The total dechlorination decreased significantly when the ethanol was removed from the feed, indicating that the ethanol stabilized dechlorination.
WAGGONER, L.O.
2000-05-16
As radiation safety specialists, one of the things we are required to do is evaluate tools, equipment, materials and work practices and decide whether the use of these products or work practices will reduce radiation dose or risk to the environment. There is a tendency for many workers that work with radioactive material to accomplish radiological work the same way they have always done it rather than look for new technology or change their work practices. New technology is being developed all the time that can make radiological work easier and result in less radiation dose to the worker or reduce the possibility that contamination will be spread to the environment. As we discuss the various tools and techniques that reduce radiation dose, keep in mind that the radiological controls should be reasonable. We can not always get the dose to zero, so we must try to accomplish the work efficiently and cost-effectively. There are times we may have to accept there is only so much you can do. The goal is to do the smart things that protect the worker but do not hinder him while the task is being accomplished. In addition, we should not demand that large amounts of money be spent for equipment that has marginal value in order to save a few millirem. We have broken the handout into sections that should simplify the presentation. Time, distance, shielding, and source reduction are methods used to reduce dose and are covered in Part I on work execution. We then look at operational considerations, radiological design parameters, and discuss the characteristics of personnel who deal with ALARA. This handout should give you an overview of what it takes to have an effective dose reduction program.
Replacement, reduction and refinement.
Flecknell, Paul
2002-01-01
In 1959, William Russell and Rex Burch published "The Principles of Humane Experimental Technique". They proposed that if animals were to be used in experiments, every effort should be made to Replace them with non-sentient alternatives, to Reduce to a minimum the number of animals used, and to Refine experiments which used animals so that they caused the minimum pain and distress. These guiding principles, the "3 Rs" of animal research, were initially given little attention. Gradually, however, they have become established as essential considerations when animals are used in research. They have influenced new legislation aimed at controlling the use of experimental animals, and in the United Kingdom they have become formally incorporated into the Animal (Scientific) Procedures Act. The three principles, of Replacement, Reduction and Refinement, have also proven to be an area of common ground for research workers who use animals, and those who oppose their use. Scientists, who accept the need to use animals in some experiments, would also agree that it would be preferable not to use animals. If animals were to be used, as few as possible should be used and they should experience a minimum of pain or distress. Many of those who oppose animal experimentation, would also agree that until animal experimentation is stopped, Russell and Burch's 3Rs provide a means to improve animal welfare. It has also been recognised that adoption of the 3Rs can improve the quality of science. Appropriately designed experiments that minimise variation, provide standardised optimum conditions of animals care and minimise unnecessary stress or pain, often yield better more reliable data. Despite the progress made as a result of attention to these principles, several major problems have been identified. When replacing animals with alternative methods, it has often proven difficult to formally validate the alternative. This has proven a particular problem in regulatory toxicology
NASA Technical Reports Server (NTRS)
Kenny, Patrick
2004-01-01
The Acoustics Branch is responsible for reducing noise levels for jet and fan components on aircraft engines. To do this, data must be measured and calibrated accurately to ensure validity of test results. This noise reduction is accomplished by modifications to hardware such as jet nozzles, and by the use of other experimental hardware such as fluidic chevrons, elliptic cores, and fluidic shields. To insure validity of data calibration, a variety of software is used. This software adjusts the sound amplitude and frequency to be consistent with data taken on another day. Both the software and the hardware help make noise reduction possible. work properly. These software programs were designed to make corrections for atmosphere, shear, attenuation, electronic, and background noise. All data can be converted to a one-foot lossless condition, using the proper software corrections, making a reading independent of weather and distance. Also, data can be transformed from model scale to full scale for noise predictions of a real flight. Other programs included calculations of Over All Sound Pressure Level (OASPL), Effective Perceived Noise Level (EPNL). OASPL is the integration of sound with respect to frequency, and EPNL is weighted for a human s response to different sound frequencies and integrated with respect to time. With the proper software correction, data taken in the NATR are useful in determining ways to reduce noise. display any difference between two or more data files. Using this program and graphs of the data, the actual and predicted data can be compared. This software was tested on data collected at the Aero Acoustic Propulsion Laboratory (AAPL) using a variety of window types and overlaps. Similarly, short scripts were written to test each individual program in the software suite for verification. Each graph displays both the original points and the adjusted points connected with lines. During this summer, data points were taken during a live experiment
Fricke, V.
1999-12-15
The Size Reduction Machine (SRM) is a mobile platform capable of shearing various shapes and types of metal components at a variety of elevations. This shearing activity can be performed without direct physical movement and placement of the shear head by the operator. The base unit is manually moved and roughly aligned to each cut location. The base contains the electronics: hydraulic pumps, servos, and actuators needed to move the shear-positioning arm. The movable arm allows the shear head to have six axes of movement and to cut to within 4 inches of a wall surface. The unit has a slick electrostatic capture coating to assist in external decontamination. Internal contamination of the unit is controlled by a high-efficiency particulate air (HEPA) filter on the cooling inlet fan. The unit is compact enough to access areas through a 36-inch standard door opening. This paper is an Innovative Technology Summary Report designed to provide potential users with the information they need to quickly determine if a technology would apply to a particular environmental management problem. They also are designed for readers who may recommend that a technology be considered by prospective users.
DeCamp, Malcolm M.; McKenna, Robert J.; Deschamps, Claude C.; Krasna, Mark J.
2008-01-01
The objective of lung volume reduction surgery (LVRS) is the safe, effective, and durable palliation of dyspnea in appropriately selected patients with moderate to severe emphysema. Appropriate patient selection and preoperative preparation are prerequisites for successful LVRS. An effective LVRS program requires participation by and communication between experts from pulmonary medicine, thoracic surgery, thoracic anesthesiology, critical care medicine, rehabilitation medicine, respiratory therapy, chest radiology, and nursing. The critical analysis of perioperative outcomes has influenced details of the conduct of the procedure and has established a bilateral, stapled approach as the standard of care for LVRS. The National Emphysema Treatment Trial (NETT) remains the world's largest multi-center, randomized trial comparing LVRS to maximal medical therapy. NETT purposely enrolled a broad spectrum of anatomic patterns of emphysema. This, along with the prospective, audited collection of extensive demographic, physiologic, radiographic, surgical and quality-of-life data, has positioned NETT as the most robust repository of evidence to guide the refinement of patient selection criteria for LVRS, to assist surgeons in providing optimal intraoperative and postoperative care, and to establish benchmarks for survival, complication rates, return to independent living, and durability of response. This article reviews the evolution of current LVRS practice with a particular emphasis on technical aspects of the operation, including the predictors and consequences of its most common complications. PMID:18453353
Model reduction for flexible structures
NASA Technical Reports Server (NTRS)
Gawronski, Wodek; Juang, Jer-Nan
1990-01-01
Several conditions for a near-optimal reduction of general dynamic systems are presented focusing on the reduction in balanced and modal coordinates. It is shown that model and balanced reductions give very different results for the flexible structure with closely-spaced natural frequencies. In general, balanced reduction is found to give better results. A robust model reduction technique was developed to study the sensitivity of modeling error to variations in the damping of a structure. New concepts of grammians defined over a finite time and/or a frequency interval are proposed including computational procedures for evaluating them. Application of the model reduction technique to these grammians is considered to lead to a near-optimal reduced model which closely reproduces the full system output in the time and/or frequency interval.
Emerging Community Noise Reduction Approaches
NASA Technical Reports Server (NTRS)
Envia, Edmane
2012-01-01
An overview of the current NASA research portfolio in the area of aircraft noise reduction is presented. The emphasis of the research described herein is on meeting the aggressive near- and mid-term national goals for reducing aircraft noise emissions, which NASA internal studies have shown to be feasible using noise reduction technologies currently being developed in-house or in partnership with NASA s industry and academic partners. While NASA has an active research effort in airframe noise reduction, this overview focuses on propulsion noise reduction only.
Fraction reduction in membrane systems.
Guo, Ping; Zhang, Hong; Chen, Haizhu; Liu, Ran
2014-01-01
Fraction reduction is a basic computation for rational numbers. P system is a new computing model, while the current methods for fraction reductions are not available in these systems. In this paper, we propose a method of fraction reduction and discuss how to carry it out in cell-like P systems with the membrane structure and the rules with priority designed. During the application of fraction reduction rules, synchronization is guaranteed by arranging some special objects in these rules. Our work contributes to performing the rational computation in P systems since the rational operands can be given in the form of fraction. PMID:24772037
Higgs production and decay in models of a warped extra dimension with a bulk Higgs
Archer, Paul R.; Carena, Marcela; Carmona, Adrian; Neubert, Matthias
2015-01-13
Warped extra-dimension models in which the Higgs boson is allowed to propagate in the bulk of a compact AdS5 space are conjectured to be dual to models featuring a partially composite Higgs boson. They offer a framework with which to investigate the implications of changing the scaling dimension of the Higgs operator, which can be used to reduce the constraints from electroweak precision data. In the context of such models, we calculate the cross section for Higgs production in gluon fusion and the H → γγ decay rate and show that they are finite (at one-loop order) as a consequencemore » of gauge invariance. The extended scalar sector comprising the Kaluza-Klein excitations of the Standard Model scalars is constructed in detail. The largest effects are due to virtual KK fermions, whose contributions to the cross section and decay rate introduce a quadratic sensitivity to the maximum allowed value y* of the random complex entries of the 5D anarchic Yukawa matrices. We find an enhancement of the gluon-fusion cross section and a reduction of the H → γγ rate as well as of the tree-level Higgs couplings to fermions and electroweak gauge bosons. As a result, we perform a detailed study of the correlated signal strengths for different production mechanisms and decay channels as functions of y*, the mass scale of Kaluza-Klein resonances and the scaling dimension of the composite Higgs operator.« less
Higgs production and decay in models of a warped extra dimension with a bulk Higgs
Archer, Paul R.; Carena, Marcela; Carmona, Adrian; Neubert, Matthias
2015-01-13
Warped extra-dimension models in which the Higgs boson is allowed to propagate in the bulk of a compact AdS_{5} space are conjectured to be dual to models featuring a partially composite Higgs boson. They offer a framework with which to investigate the implications of changing the scaling dimension of the Higgs operator, which can be used to reduce the constraints from electroweak precision data. In the context of such models, we calculate the cross section for Higgs production in gluon fusion and the H → γγ decay rate and show that they are finite (at one-loop order) as a consequence of gauge invariance. The extended scalar sector comprising the Kaluza-Klein excitations of the Standard Model scalars is constructed in detail. The largest effects are due to virtual KK fermions, whose contributions to the cross section and decay rate introduce a quadratic sensitivity to the maximum allowed value y_{*} of the random complex entries of the 5D anarchic Yukawa matrices. We find an enhancement of the gluon-fusion cross section and a reduction of the H → γγ rate as well as of the tree-level Higgs couplings to fermions and electroweak gauge bosons. As a result, we perform a detailed study of the correlated signal strengths for different production mechanisms and decay channels as functions of y_{*}, the mass scale of Kaluza-Klein resonances and the scaling dimension of the composite Higgs operator.
NASA Astrophysics Data System (ADS)
Yin, Shaoyu; Wang, Bin; Mann, Robert; Lee, Chong Oh; Lin, Chi-Yong; Su, Ru-Keng
2010-09-01
We investigate the stability of a new warped black string with nontrivial topologies in five-dimensional anti-de Sitter spacetime. After studying the linear gravitational perturbation, we find that this black string is unstable when the Kaluza-Klein mass falls in a certain range, and the instability exists for all topological spacetimes.
Signatures from an extra-dimensional seesaw model
Blennow, Mattias; Melbeus, Henrik; Ohlsson, Tommy; Zhang He
2010-08-15
We study the generation of small neutrino masses in an extra-dimensional model, where singlet fermions are allowed to propagate in the extra dimension, while the standard model particles are confined to a brane. Motivated by the fact that extra-dimensional models are nonrenormalizable, we truncate the Kaluza-Klein towers at a maximal Kaluza-Klein number. This truncation, together with the structure of the bulk Majorana mass term, motivated by the Sherk-Schwarz mechanism, implies that the Kaluza-Klein modes of the singlet fermions pair to form Dirac fermions, except for a number of unpaired Majorana fermions at the top of each tower. These heavy Majorana fermions are the only sources of lepton number breaking in the model, and similarly to the type-I seesaw mechanism, they naturally generate small masses for the left-handed neutrinos. The lower Kaluza-Klein modes mix with the light neutrinos, and the mixing effects are not suppressed with respect to the light-neutrino masses. Compared to conventional fermionic seesaw models, such mixing can be more significant. We study the signals of this model at the Large Hadron Collider, and find that the current low-energy bounds on the nonunitarity of the leptonic mixing matrix are strong enough to exclude an observation.
A characterization for the sensitivity of a metric
NASA Astrophysics Data System (ADS)
Molaei, Mohammadreza; Khajoei, Najmeh
2016-08-01
In this paper we introduce the universal functions which describe the sensitivity of metrics on the local charts of their ambient manifolds. We find these functions for Bianchi type II, V, VII and IX cosmological models. We also find these values for Kaluza-Klein and FRW space-times.
Proton stability and dark matter : are they related?
Servant, G.; High Energy Physics
2004-06-01
We address the problem of baryon number violation in Randall-Sundrum backgrounds and provide a solution leading to a stable light Kaluza--Klein fermion in warped GUT. This adds to the list of dark matter candidates which stability can follow from ensuring proton stability in weak scale extensions of the Standard Model.
Selective reduction in multiple gestation.
Osborn, M R
1989-07-01
As new advances in the treatment and management of infertility become available, it is hoped that selective reduction procedures will no longer be necessary. In the interim, however, it is imperative that nurses be knowledgeable about the options available to parents experiencing multifetal pregnancy, including the choice of selective reduction procedures. PMID:2732940
Reduction-Fired Seedpod Bowls.
ERIC Educational Resources Information Center
Beyke, Rod
2001-01-01
Focuses on a reduction-firing process with an aim of producing high-quality blackware similar to the black-on-black pottery of Maria Martinez and other American Indian potters. Includes a lesson on creating reduction-fired seedpod bowls, lists of instructional resources and materials, and the objectives and evaluation. (CMK)
Noise Reduction by Signal Accumulation
ERIC Educational Resources Information Center
Kraftmakher, Yaakov
2006-01-01
The aim of this paper is to show how the noise reduction by signal accumulation can be accomplished with a data acquisition system. This topic can be used for student projects. In many cases, the noise reduction is an unavoidable part of experimentation. Several techniques are known for this purpose, and among them the signal accumulation is the…
Reduction of chemical reaction models
NASA Technical Reports Server (NTRS)
Frenklach, Michael
1991-01-01
An attempt is made to reconcile the different terminologies pertaining to reduction of chemical reaction models. The approaches considered include global modeling, response modeling, detailed reduction, chemical lumping, and statistical lumping. The advantages and drawbacks of each of these methods are pointed out.
The Ethics of Interproximal Reduction.
Noar, Joseph H; Kneafsey, Louise C
2015-12-01
Interproximal reduction (IPR) has become particularly popular with the use of removable aligners. Clinical and ethical factors concerning the use of interproximal reduction to facilitate orthodontic alignment are discussed. CPD/Clinical Relevance: An understanding of the aetiological factors of a malocclusion is essential to enable full discussion of the risks and benefits, or the alternatives to IPR. PMID:26855997
DRAG REDUCTION WITH SUPERHYDROPHOBIC RIBLETS
Barbier, Charlotte N; D'Urso, Brian R; Jenner, Elliot
2012-01-01
Samples combining riblets and superhydrophobic surfaces are fabricated at University of Pittsburgh and their drag reduction properties are studied at the Center for Nanophase Materials Sciences (CNMS) in Oak Ridge National Laboratory with a commercial cone-and-plate rheometer. In parallel to the experiments, numerical simulations are performed in order to estimate the slip length at high rotational speed. For each sample, a drag reduction of at least 5% is observed in both laminar and turbulent regime. At low rotational speed, drag reduction up to 30% is observed with a 1 mm deep grooved sample. As the rotational speed increases, a secondary flow develops causing a slight decrease in drag reductions. However, drag reduction above 15% is still observed for the large grooved samples. In the turbulent regime, the 100 microns grooved sample becomes more efficient than the other samples in drag reduction and manages to sustain a drag reduction above 15%. Using the simulations, the slip length of the 100 micron grooved sample is estimated to be slightly above 100 micron in the turbulent regime.
Technologies for Aircraft Noise Reduction
NASA Technical Reports Server (NTRS)
Huff, Dennis L.
2006-01-01
Technologies for aircraft noise reduction have been developed by NASA over the past 15 years through the Advanced Subsonic Technology (AST) Noise Reduction Program and the Quiet Aircraft Technology (QAT) project. This presentation summarizes highlights from these programs and anticipated noise reduction benefits for communities surrounding airports. Historical progress in noise reduction and technologies available for future aircraft/engine development are identified. Technologies address aircraft/engine components including fans, exhaust nozzles, landing gear, and flap systems. New "chevron" nozzles have been developed and implemented on several aircraft in production today that provide significant jet noise reduction. New engines using Ultra-High Bypass (UHB) ratios are projected to provide about 10 EPNdB (Effective Perceived Noise Level in decibels) engine noise reduction relative to the average fleet that was flying in 1997. Audio files are embedded in the presentation that estimate the sound levels for a 35,000 pound thrust engine for takeoff and approach power conditions. The predictions are based on actual model scale data that was obtained by NASA. Finally, conceptual pictures are shown that look toward future aircraft/propulsion systems that might be used to obtain further noise reduction.
Fan Noise Reduction: An Overview
NASA Technical Reports Server (NTRS)
Envia, Edmane
2001-01-01
Fan noise reduction technologies developed as part of the engine noise reduction element of the Advanced Subsonic Technology Program are reviewed. Developments in low-noise fan stage design, swept and leaned outlet guide vanes, active noise control, fan flow management, and scarfed inlet are discussed. In each case, a description of the method is presented and, where available, representative results and general conclusions are discussed. The review concludes with a summary of the accomplishments of the AST-sponsored fan noise reduction research and a few thoughts on future work.
Geometric Quantization and Foliation Reduction
NASA Astrophysics Data System (ADS)
Skerritt, Paul
A standard question in the study of geometric quantization is whether symplectic reduction interacts nicely with the quantized theory, and in particular whether "quantization commutes with reduction." Guillemin and Sternberg first proposed this question, and answered it in the affirmative for the case of a free action of a compact Lie group on a compact Kahler manifold. Subsequent work has focused mainly on extending their proof to non-free actions and non-Kahler manifolds. For realistic physical examples, however, it is desirable to have a proof which also applies to non-compact symplectic manifolds. In this thesis we give a proof of the quantization-reduction problem for general symplectic manifolds. This is accomplished by working in a particular wavefunction representation, associated with a polarization that is in some sense compatible with reduction. While the polarized sections described by Guillemin and Sternberg are nonzero on a dense subset of the Kahler manifold, the ones considered here are distributional, having support only on regions of the phase space associated with certain quantized, or "admissible", values of momentum. We first propose a reduction procedure for the prequantum geometric structures that "covers" symplectic reduction, and demonstrate how both symplectic and prequantum reduction can be viewed as examples of foliation reduction. Consistency of prequantum reduction imposes the above-mentioned admissibility conditions on the quantized momenta, which can be seen as analogues of the Bohr-Wilson-Sommerfeld conditions for completely integrable systems. We then describe our reduction-compatible polarization, and demonstrate a one-to-one correspondence between polarized sections on the unreduced and reduced spaces. Finally, we describe a factorization of the reduced prequantum bundle, suggested by the structure of the underlying reduced symplectic manifold. This in turn induces a factorization of the space of polarized sections that agrees
Subsolidus reduction of lunar spinels.
NASA Technical Reports Server (NTRS)
Haggerty, S. E.
1971-01-01
Discussion of evidence that some lunar basalts must have exceeded the lower limit of crystallization oxygen fugacity (fO2) by several orders of magnitude. The evidence is based primarily on the decomposition of Cr-Al-ulvospinel, and is further supported in one case by the decomposition of olivine. The data suggest that some rocks have undergone intense nonequilibrium subsolidus reduction. The reduction phenomenon is widespread, and is considered to have developed either during initial deuteric cooling or as a result of a postcrystallization reduction event.
Reductive Degradation: Versatile, Low Cost.
ERIC Educational Resources Information Center
Water and Sewage Works, 1979
1979-01-01
This article discusses the use of reductive degradation as an economical and effective treatment of chlorinated hydrocarbons. Comparisons with activated carbon treatment show lower capital equipment and treatment costs. (CS)
2dfdr: Data reduction software
NASA Astrophysics Data System (ADS)
AAO software Team
2015-05-01
2dfdr is an automatic data reduction pipeline dedicated to reducing multi-fibre spectroscopy data, with current implementations for AAOmega (fed by the 2dF, KOALA-IFU, SAMI Multi-IFU or older SPIRAL front-ends), HERMES, 2dF (spectrograph), 6dF, and FMOS. A graphical user interface is provided to control data reduction and allow inspection of the reduced spectra.
Chromium reduction in Pseudomonas putida
Ishibashi, Y.; Cervantes, C.; Silver, S. )
1990-07-01
Reduction of hexavalent chromium (chromate) to less-toxic trivalent chromium was studied by using cell suspensions and cell-free supernatant fluids from Pseudomonas putida PRS2000. Chromate reductase activity was associated with soluble protein and not with the membrane fraction. The crude enzyme activity was heat labile and showed a K{sub m} of 40 {mu}M CrO{sub 4}{sup 2{minus}}. Neither sulfate nor nitrate affected chromate reduction either in vitro or with intact cells.
Rapid reduction of titanium dioxide nano-particles by reduction with a calcium reductant
NASA Astrophysics Data System (ADS)
Kikuchi, Tatsuya; Yoshida, Masumi; Matsuura, Shiki; Natsui, Shungo; Tsuji, Etsuji; Habazaki, Hiroki; Suzuki, Ryosuke O.
2014-09-01
Micro-, submicron-, and nano-scale titanium dioxide particles were reduced by reduction with a metallic calcium reductant in calcium chloride molten salt at 1173 K, and the reduction mechanism of the oxides by the calcium reductant was explored. These oxide particles, metallic calcium as a reducing agent, and calcium chloride as a molten salt were placed in a titanium crucible and heated under an argon atmosphere. Titanium dioxide was reduced to metallic titanium through a calcium titanate and lower titanium oxide, and the materials were sintered together to form a micro-porous titanium structure in molten salt at high temperature. The reduction rate of titanium dioxide was observed to increase with decreasing particle size; accordingly, the residual oxygen content in the reduced titanium decreases. The obtained micro-porous titanium appeared dark gray in color because of its low surface reflection. Micro-porous metallic titanium with a low oxygen content (0.42 wt%) and a large surface area (1.794 m2 g-1) can be successfully obtained by reduction under optimal conditions.
Crystallographic Control in Ilmenite Reduction
NASA Astrophysics Data System (ADS)
de Vries, M. L.; Grey, I. E.; Fitz Gerald, J. D.
2007-04-01
Scanning electron microscopy and transmission electron microscopy techniques were used to characterize the products from hydrogen reduction of polygranular synthetic ilmenite discs at temperatures in the range 823 to 1173 K and pressures in the range 1 to 13 atm. Reduction commences at grain boundaries and cracks and advances progressively to grain interiors. Within individual grains, the morphology of the reduction products was found to be crystallographically controlled. Near parallel bands of metallic iron (Fe m ) form within each grain, aligned with the basal plane of ilmenite (il) (0001) il . The separation between bands is of the order of 1 μm and is relatively constant with change of pressure and temperature. In the interband region, conversion of ilmenite to rutile occurs preferentially parallel to \\{ 11ifmmodeexpandafterbarelseexpandafter\\=fi{2}0\\} _{{il}} ilmenite planes, generating platelets of rutile that grow normal to the Fe m bands. The intergrain duplex morphology of the reduction products closely resembles cellular precipitation in alloys. At reduction temperatures above ˜1000 K, the interband region comprises dense, nonporous oriented intergrowths of rutile platelets and residual ilmenite, whereas below ˜900 K, the interband region contains a fine, filamentary network of pores. In the intermediate temperature regime, a change from dense to porous interband region occurs with increasing pressure. The observations have been interpreted in terms of the relative rates of interfacial chemical reaction and solid-state diffusion, with the latter having a controlling influence at lower temperatures or higher pressures.
Midwestern Greenhouse Gas Reduction Accord
2007-07-01
The Midwestern Greenhouse Gas Reduction Acccord, or Midwestern Greenhouse gas Accord (MGA), is a regional agreement by governors of the states in the US Midwest and one Canadian province to reduce greenhouse gas emissions to combat climate change. Signatories to the accord include the US states of Minnesota, Wisconsin, Illinois, Indiana, Iowa, Michigan, Kansas, Ohio and South Dakota, and the Canadian Province of Manitoba. The accord, signed on November 15, 2007, established the Midwestern Greenhouse Gas Reduction Program, which aims to: establish greenhouse gas reduction targets and timeframes consistent with MGA member states' targets; develop a market-based and multi-sector cap-and-trade mechanism to help achieve those reduction targets; establish a system to enable tracking, management, and crediting for entities that reduce greenhouse gas emissions; and develop and implement additional steps as needed to achieve the reduction targets, such as a low-carbon fuel standards and regional incentives and funding mechanisms. The GHG registry will be managed by the Climate Registry, which manages the registry for other US state schemes. One of the first actions was to convene an Energy Security under Climate Stewardship Platform to guide future development of the Midwest's energy economy.
Toxicity reduction in industrial effluents
Lankford, P.W.; Eckenfelder, W.W.
1990-01-01
The toxicity of manufacturing wastewaters to fish and other aquatic organisms is now being used by state and federal regulators to monitor and restrict industrial wastewater discharges. As a result, there is a great need for guidance on the subject of aquatic toxicity reduction in the field of industrial water pollution control. This book is a comprehensive reference source on the testing protocols, comparative data, and treatment techniques for effective toxicity reduction. Included in this book are detailed chapters covering various methods for toxicity reduction, such as the removal of metals, aerobic biological treatment, stripping of volatile organics, and management of sludges from toxic wastewater treatment. The book features: a complete overview of the subject, including background material for newcomers to the field; a basic summary and comparison of alternate treatment procedures; the latest methods for the identification of toxic components that readers can use for testing in their own laboratories; a description of applicable technologies for toxicity reduction; actual data from the use of processes that allow readers to compare technologies; solids management requirements including handling and disposal; useful economic comparisons of technologies; and illustrative case studies that demonstrate the application of the latest toxicity reduction technology and data to specific situations. Eleven chapters are processed separately in the appropriate data bases.
Current trends in breast reduction.
Roje, Zdravko; Roje, Zeljka; Milosević, Milan; Varvodić, Josip; Mance, Marko
2012-06-01
Results of our study describe the long term effects of reduction mammaplasty. Many women with excessively small or large breasts have an altered personal self-image and often suffer from low self-esteem and other psychological stresses. This procedure is designed to reduce and reshape large breasts, and since the size, shape, and symmetry of a woman's breasts can have a profound effect on her mental and physical well-being it is important to observe the patient's long-term outcome. Currently, breast reduction surgery is safe, effective and beneficial to the patient. In Croatia, reduction mammoplasty is often excluded from the general health care plan. The distinction between "reconstructive" versus "cosmetic" breast surgery is very well defined by the American Society of Plastic Surgeons Board of Directors. Unfortunately, the Croatian Health Society has yet to standardize such a distinction. There is an imperative need for evidence-based selection criteria. We retrospectively analyzed data of 59 female patients suffering from symptomatic macromastia who underwent reduction mammaplasty over a 16 year period (1995 until 2011). Our aim was to compare and contrast the various techniques available for reduction mammaplasty and to determine, based on patient outcome and satisfaction, which technique is most suited for each patient. The results of our study generally reinforce the observation that reduction mammaplasty significantly provides improvements in health status, long-term quality of life, postsurgical breast appearance and significantly decrease physical symptoms of pain. A number of 59 consecutive cases were initially treated with the four different breast reduction techniques: inverted-T scat or Wisa pattern breast reduction, vertical reduction mammaplasty, simplified vertical reduction mammaplasty, inferior pedicle and free nipple graft techniques. The average clinical follow-up period was 6-months, and included 48 patients. The statistical analysis of the
Microbial reduction of iron ore
Hoffmann, M.R.; Arnold, R.G.; Stephanopoulos, G.
1989-11-14
A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry. 11 figs.
Microbial reduction of iron ore
Hoffmann, Michael R.; Arnold, Robert G.; Stephanopoulos, Gregory
1989-01-01
A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry.
Closed reduction of a fractured bone
Fracture reduction - closed ... Closed reduction is a procedure to set (reduce) a broken bone without surgery. This allows the bone ... soon as possible after the bone breaks. A closed reduction can be done by an orthopedic surgeon ( ...
Uranium isotopes fingerprint biotic reduction
Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng; Monga, Nikhil; Romaniello, Stephen J.; Weyer, Stefan; Bernier-Latmani, Rizlan
2015-04-20
Knowledge of paleo-redox conditions in the Earth’s history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U), i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth’s crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. In addition, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium.
Uranium isotopes fingerprint biotic reduction
Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng; Monga, Nikhil; Romaniello, Stephen J.; Weyer, Stefan; Bernier-Latmani, Rizlan
2015-04-20
Knowledge of paleo-redox conditions in the Earth’s history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U),more » i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth’s crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. In addition, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium.« less
Uranium isotopes fingerprint biotic reduction.
Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng; Monga, Nikhil; Romaniello, Stephen J; Weyer, Stefan; Bernier-Latmani, Rizlan
2015-05-01
Knowledge of paleo-redox conditions in the Earth's history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U), i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth's crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. Additionally, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium. PMID:25902522
Uranium isotopes fingerprint biotic reduction
Stylo, Malgorzata; Neubert, Nadja; Wang, Yuheng; Monga, Nikhil; Romaniello, Stephen J.; Weyer, Stefan; Bernier-Latmani, Rizlan
2015-01-01
Knowledge of paleo-redox conditions in the Earth’s history provides a window into events that shaped the evolution of life on our planet. The role of microbial activity in paleo-redox processes remains unexplored due to the inability to discriminate biotic from abiotic redox transformations in the rock record. The ability to deconvolute these two processes would provide a means to identify environmental niches in which microbial activity was prevalent at a specific time in paleo-history and to correlate specific biogeochemical events with the corresponding microbial metabolism. Here, we demonstrate that the isotopic signature associated with microbial reduction of hexavalent uranium (U), i.e., the accumulation of the heavy isotope in the U(IV) phase, is readily distinguishable from that generated by abiotic uranium reduction in laboratory experiments. Thus, isotope signatures preserved in the geologic record through the reductive precipitation of uranium may provide the sought-after tool to probe for biotic processes. Because uranium is a common element in the Earth’s crust and a wide variety of metabolic groups of microorganisms catalyze the biological reduction of U(VI), this tool is applicable to a multiplicity of geological epochs and terrestrial environments. The findings of this study indicate that biological activity contributed to the formation of many authigenic U deposits, including sandstone U deposits of various ages, as well as modern, Cretaceous, and Archean black shales. Additionally, engineered bioremediation activities also exhibit a biotic signature, suggesting that, although multiple pathways may be involved in the reduction, direct enzymatic reduction contributes substantially to the immobilization of uranium. PMID:25902522
Technologies for Turbofan Noise Reduction
NASA Technical Reports Server (NTRS)
Huff, Dennis
2005-01-01
An overview presentation of NASA's engine noise research since 1992 is given for subsonic commercial aircraft applications. Highlights are included from the Advanced Subsonic Technology (AST) Noise Reduction Program and the Quiet Aircraft Technology (QAT) project with emphasis on engine source noise reduction. Noise reduction goals for 10 EPNdB by 207 and 20 EPNdB by 2022 are reviewed. Fan and jet noise technologies are highlighted from the AST program including higher bypass ratio propulsion, scarf inlets, forward-swept fans, swept/leaned stators, chevron nozzles, noise prediction methods, and active noise control for fans. Source diagnostic tests for fans and jets that have been completed over the past few years are presented showing how new flow measurement methods such as Particle Image Velocimetry (PIV) have played a key role in understanding turbulence, the noise generation process, and how to improve noise prediction methods. Tests focused on source decomposition have helped identify which engine components need further noise reduction. The role of Computational AeroAcoustics (CAA) for fan noise prediction is presented. Advanced noise reduction methods such as Hershel-Quincke tubes and trailing edge blowing for fan noise that are currently being pursued n the QAT program are also presented. Highlights are shown form engine validation and flight demonstrations that were done in the late 1990's with Pratt & Whitney on their PW4098 engine and Honeywell on their TFE-731-60 engine. Finally, future propulsion configurations currently being studied that show promise towards meeting NASA's long term goal of 20 dB noise reduction are shown including a Dual Fan Engine concept on a Blended Wing Body aircraft.
2008 world direct reduction statistics
2009-07-01
This supplement discusses total direct reduced iron (DRI) production for 2007 and 2008 by process. Total 2008 production by MIDREX(reg sign) direct reduction process plants was over 39.8 million tons. The total of all coal-based processes was 17.6 million tons. Statistics for world DRI production are also given by region for 2007 and 2008 and by year (1970-2009). Capacity utilization for 2008 by process is given. World DRI production by region and by process is given for 1998-2008 and world DRI shipments are given from the 1970s to 2008. A list of world direct reduction plants is included.
Dimensional Reduction and Hadronic Processes
Signer, Adrian; Stoeckinger, Dominik
2008-11-23
We consider the application of regularization by dimensional reduction to NLO corrections of hadronic processes. The general collinear singularity structure is discussed, the origin of the regularization-scheme dependence is identified and transition rules to other regularization schemes are derived.
PESTICIDE REDUCTION THROUGH PRECISION TARGETING
The rationale for studying insecticide resistance in this SERDP Effort stems directly from the requirement to know the effectiveness of a particular mitigation measure before it can be recommended in a comparative risk reduction environment. The following report deals with insec...
Graded geometry and Poisson reduction
Cattaneo, A. S.; Zambon, M.
2009-02-02
The main result extends the Marsden-Ratiu reduction theorem in Poisson geometry, and is proven by means of graded geometry. In this note we provide the background material about graded geometry necessary for the proof. Further, we provide an alternative algebraic proof for the main result.
Dorsal Hump Reduction and Osteotomies.
Azizzadeh, Babak; Reilly, Michael
2016-01-01
This article discusses the technique for planning, executing, and troubleshooting dorsal hump reduction for the cosmetic rhinoplasty patient. Details of the discussion include the necessary elements of the preoperative consultation with the patient, the specific instruments used to effectively and reproducibly create osteotomies, the anatomic and patient variables that require special attention, and the necessary measures to guard against potential complications. PMID:26616694
Functionalization of Organotrifluoroborates: Reductive Amination
Cooper, David J.
2010-01-01
Herein we report the conversion of aldehyde-containing potassium and tetrabutylammonium organotrifluoroborates to the corresponding amines through reductive amination protocols. Potassium formate facilitated by catalytic palladium acetate, sodium triacetoxyborohydride, and pyridine borane have all served as effective hydride donors, reducing the initially formed imines or iminium ions to provide the corresponding amines. PMID:18412389
Palladium Catalyzed Reduction of Nitrobenzene.
ERIC Educational Resources Information Center
Mangravite, John A.
1983-01-01
Compares two palladium (Pd/C) reducing systems to iron/tin-hydrochloric acid (Fe/HCl and Sn/HCl) reductions and suggests an efficient, clean, and inexpensive procedures for the conversion of nitrobenzene to aniline. Includes laboratory procedures used and discussion of typical results obtained. (JN)
Women, harm reduction and HIV.
Pinkham, Sophie; Malinowska-Sempruch, Kasia
2008-05-01
Gender shapes the experience of drug use and its associated risks. In most parts of the world, however, harm reduction and drug treatment programmes that tailor their services to meet women's needs are rare or nonexistent. Many existing services inadvertently exclude women, and discriminatory policies and social stigma drive women drug users from care and expose them to human rights abuses. Women drug users often provide sex in exchange for housing, sustenance and protection, suffer violence from sexual partners and practise unsafe sex. This paper, drawing upon evidence from existing studies, examines ways in which gender-related factors can increase women drug users' vulnerability and decrease their access to harm reduction, drug treatment and sexual and reproductive health services. It recommends designing services with low-threshold access for women drug users that help them to become more independent, involving the women in designing services and policies, making programmes available for mothers, incorporating sexual and reproductive health into harm reduction services, providing gender-sensitive drug treatment and integrated harm reduction programmes for drug-using sex workers, connecting with domestic violence and rape prevention services and educating mainstream providers. Overall, investigating the circumstances women drug users face will help to formulate policies and programmes that better serve women who use drugs. PMID:18513618
Background reduction in cryogenic detectors
Bauer, Daniel A.; /Fermilab
2005-04-01
This paper discusses the background reduction and rejection strategy of the Cryogenic Dark Matter Search (CDMS) experiment. Recent measurements of background levels from CDMS II at Soudan are presented, along with estimates for future improvements in sensitivity expected for a proposed SuperCDMS experiment at SNOLAB.
Workforce Reductions. An Annotated Bibliography.
ERIC Educational Resources Information Center
Hickok, Thomas A.; Hickok, Thomas A.
This report, which is based on a review of practitioner-oriented sources and scholarly journals, uses a three-part framework to organize annotated bibliographies that, together, list a total of 104 sources that provide the following three perspectives on work force reduction issues: organizational, organizational-individual relationship, and…
Preferences for Rape Reduction Strategies.
ERIC Educational Resources Information Center
Krulewitz, Judith E.; Kahn, Arnold S.
1983-01-01
Surveyed 53 female and 36 male college students to examine attitudes on the perceived effectiveness of four rape reduction strategies. Generally aggressive strategies and those placing the locus of responsibility for change upon women were considered most effective. Sex role attitudes were more predictive than subject sex differences. (JAC)
ENERGY CONSERVATION THROUGH SOURCE REDUCTION
This report deals with energy conservation through reduction in generation of post-consumer solid waste. The objective, scope, methodology and summary of the report are presented in Section 1. Section 2 contains the conclusions. Section 3 presents a review of output and input app...
Poverty Reduction Begins with Children.
ERIC Educational Resources Information Center
United Nations Children's Fund, New York, NY.
This report describes how children bear the brunt of poverty and explains why they are central to poverty reduction in developing nations. The report also illustrates UNICEF's support for the process of improving access to, and quality of, health care, education, water and sanitation, and child protection. It describes how the participation of the…
Substructure Search by Set Reduction
ERIC Educational Resources Information Center
Figueras, John
1972-01-01
The set reduction algorithm is based on set theory and Boolean algebra rather than the graph-theoretic approach. Time trials with a small file of organic chemical structures indicate that the algorithm can be economically used for substructure (or complete structure) sequential searches on a file containing 30,000-50,000 computer-coded structures.…
Zygomatic nonunion after reduction malarplasty.
Lee, Yoon Ho; Lee, Sang Woo
2009-05-01
Reduction malarplasty for making an oval facial shape is popular in Asia. Surgeons generally prefer the intraoral approach to minimize the surgical incision and reduce the operation time between 2 approaches--intraoral and bicoronal approaches. However, fixation can be incomplete because of the narrow operation field, which can result in zygomatic nonunion on the fixation site through the action of the masseter muscle. In the past 5 years, 6 zygomatic nonunion patients who received reduction malarplasty through the intraoral approach visited our hospital with a limitation of mouth opening and a depression on the malar area. In every case, they were corrected by rib bone interpositional or onlay graft and miniplate refixation through a previous intraoral incision. During the follow-up period, the malar area depression was corrected in most cases. However, depression of the lateral orbital rim area remained in 1 patient. Mouth opening was almost normalized after postoperative mouth opening exercises. Zygomatic nonunion after reduction malarplasty is a serious complication that is very difficult to correct. Deep understanding of the anatomy of the malar complex and the action of the masseter muscle and careful consideration of fixation during surgery is essential in reduction malarplasty. PMID:19480043
HEAT ISLAND REDUCTION STRATEGIES GUIDEBOOK
This heat island reduction strategies guidebook provides an overview of urban heat islands and steps communities can take to reduce them. In particular, this guidebook provides background basics and answers the questions: “What is a heat island?” “What are its impacts?" "What ar...
Recursions of Symmetry Orbits and Reduction without Reduction
NASA Astrophysics Data System (ADS)
Malykh, Andrei A.; Sheftel, Mikhail B.
2011-04-01
We consider a four-dimensional PDE possessing partner symmetries mainly on the example of complex Monge-Ampère equation (CMA). We use simultaneously two pairs of symmetries related by a recursion relation, which are mutually complex conjugate for CMA. For both pairs of partner symmetries, using Lie equations, we introduce explicitly group parameters as additional variables, replacing symmetry characteristics and their complex conjugates by derivatives of the unknown with respect to group parameters. We study the resulting system of six equations in the eight-dimensional space, that includes CMA, four equations of the recursion between partner symmetries and one integrability condition of this system. We use point symmetries of this extended system for performing its symmetry reduction with respect to group parameters that facilitates solving the extended system. This procedure does not imply a reduction in the number of physical variables and hence we end up with orbits of non-invariant solutions of CMA, generated by one partner symmetry, not used in the reduction. These solutions are determined by six linear equations with constant coefficients in the five-dimensional space which are obtained by a three-dimensional Legendre transformation of the reduced extended system. We present algebraic and exponential examples of such solutions that govern Legendre-transformed Ricci-flat Kähler metrics with no Killing vectors. A similar procedure is briefly outlined for Husain equation.
[Substances considered addictive: prohibition, harm reduction and risk reduction].
Menéndez, Eduardo
2012-01-01
Latin America is currently the region with the highest rate of homicides worldwide, and a large part of the killings are linked to so-called organized crime, especially drug trafficking. The trafficking of drugs is a consequence of the illegality of certain substances which - at least presently - is based in and legitimated by biomedical criteria that turns the production, commercialization and often the consumption of certain substances considered addictive into "offenses against health." This text briefly analyzes the two policies formulated and implemented thus far in terms of prohibition and harm reduction, considering the failure of prohibitionism as well as the limitations of harm reduction proposals. The constant and multiple inconsistencies and contradictions of prohibitionism are noted, indicating the necessity of regarding cautiously repeated comments about its "failure." The text proposes the implementation of a policy of risk reduction that includes not only the behavior of individuals and groups, but also the structural dimension, both in economic-political and cultural terms. PMID:23995492
Supergravities with positive definite potentials and AdSpp-waves
NASA Astrophysics Data System (ADS)
Kerimo, Johannes
Ten-dimensional superstring theory (or the conjectured nonperturbative M-theory in eleven dimensions) is the most promising candidate for a consistent quantum theory of gravity capable of unifying all known forces of nature. An important question concerning these fundamental theories is how they compactify to lower dimensions and how to obtain a real four dimensional world? In this dissertation we present new avenues for M/string theory to reduce to lower dimensions as well as to four dimensions. For example, we show that by performing a generalized Kaluza-Klein R reduction on the low-energy field theory of the heterotic string, the resulting lower dimensional theory compactifies spontaneously on S3 to give rise to (Minkowski)6 spacetime. Furthermore, a generalized reduction of M-theory on K3 x R compactifies spontaneously on S2 to give rise to a (Minkowski)4 spacetime. The generalized Kaluza-Klein reduction gauges the Cremmer-Julia type global symmetry and the homogeneous rescaling symmetry of the supergravity equations of motion by giving the higher dimensional fields an additional dependence on the circle coordinate. We apply the generalized reduction scheme to half-maximal supergravities which are obtained from the heterotic string (or the NS-NS sector of the type-II string) compactified on a (10 - D)-dimensional torus truncated to the pure supergravity multiplet. This gives rise to new gauged supergravities in diverse dimensions with supersymmetric Minkowski x sphere vacua. Since two large extra dimensions have received much attention recently, we make a detailed study of the gauged D = 6, N = (1,1) supergravity. In particular, we show that this theory allows for a consistent sphere reduction on S2 to give rise to D = 4, N = 2 supergravity coupled to a vector multiplet which can further be truncated to N = 1 supergravity with a chiral multiplet. We also investigate pp-waves in AdS backgrounds, i.e. pp-waves as solutions of gauged supergravities with AdS vacua
Wind load reduction for heliostats
Peterka, J.A.; Hosoya, N.; Bienkiewicz, B.; Cermak, J.E.
1986-05-01
This report presents the results of wind-tunnel tests supported through the Solar Energy Research Institute (SERI) by the Office of Solar Thermal Technology of the US Department of Energy as part of the SERI research effort on innovative concentrators. As gravity loads on drive mechanisms are reduced through stretched-membrane technology, the wind-load contribution of the required drive capacity increases in percentage. Reduction of wind loads can provide economy in support structure and heliostat drive. Wind-tunnel tests have been directed at finding methods to reduce wind loads on heliostats. The tests investigated primarily the mean forces, moments, and the possibility of measuring fluctuating forces in anticipation of reducing those forces. A significant increase in ability to predict heliostat wind loads and their reduction within a heliostat field was achieved.
The SPIRE Data Reduction Pipeline
NASA Astrophysics Data System (ADS)
Rizzo, D.; Lim, T.
2008-08-01
This paper describes the data reduction pipeline of the SPIRE instrument for the Herschel Space Observatory. The pipeline is being written in Java and Jython as part of the multi-platform Herschel Common Science System. We concentrate on the algorithmic design of the pipeline based on the analysis of test data. We also discuss some of the alternative designs under consideration and give the reasons for the design adopted.
Americium recovery from reduction residues
Conner, W.V.; Proctor, S.G.
1973-12-25
A process for separation and recovery of americium values from container or bomb'' reduction residues comprising dissolving the residues in a suitable acid, adjusting the hydrogen ion concentration to a desired level by adding a base, precipitating the americium as americium oxalate by adding oxalic acid, digesting the solution, separating the precipitate, and thereafter calcining the americium oxalate precipitate to form americium oxide. (Official Gazette)
Opacity incident reduction corrective action
Levyash, I.G.; Benegal, S.D.; Claase, B.J.M.
1998-07-01
This paper illustrates some of the methods used to reduce the number of package boiler opacity incidents at the Consolidated Edison Company of New York, Inc. East River Generating Station. The principal objective was to reduce opacity exceedances caused by the design of boiler auxiliaries. Opacity causes were identified and grouped. A matrix was developed to keep track of repairs and corrections on all package boilers. A special maintenance program was developed to sustain opacity reduction.
The reduction of packaging waste
Raney, E.A.; Hogan, J.J.; McCollom, M.L.; Meyer, R.J.
1994-04-01
Nationwide, packaging waste comprises approximately one-third of the waste disposed in sanitary landfills. the US Department of Energy (DOE) generated close to 90,000 metric tons of sanitary waste. With roughly one-third of that being packaging waste, approximately 30,000 metric tons are generated per year. The purpose of the Reduction of Packaging Waste project was to investigate opportunities to reduce this packaging waste through source reduction and recycling. The project was divided into three areas: procurement, onsite packaging and distribution, and recycling. Waste minimization opportunities were identified and investigated within each area, several of which were chosen for further study and small-scale testing at the Hanford Site. Test results, were compiled into five ``how-to`` recipes for implementation at other sites. The subject of the recipes are as follows: (1) Vendor Participation Program; (2) Reusable Containers System; (3) Shrink-wrap System -- Plastic and Corrugated Cardboard Waste Reduction; (4) Cardboard Recycling ; and (5) Wood Recycling.
Model Reduction in Groundwater Modeling
NASA Astrophysics Data System (ADS)
Yeh, W. W. G.
2014-12-01
Model reduction has been shown to be a very effective method for reducing the computational burden of large-scale simulations. Model reduction techniques preserve much of the physical knowledge of the system and primarily seek to remove components from the model that do not provide significant information of interest. Proper Orthogonal Decomposition (POD) is a model reduction technique by which a system of ordinary equations is projected onto a much smaller subspace in such a way that the span of the subspace is equal to the span of the original full model space. Basically, the POD technique selects a small number of orthonormal basis functions (principal components) that span the spatial variability of the solutions. In this way the state variable (head) is approximated by a linear combination of these basis functions and, using a Galerkin projection, the dimension of the problem is significantly reduced. It has been shown that for a highly discritized model, the reduced model can be two to three orders of magnitude smaller than the original model and runs 1,000 faster. More importantly, the reduced model captures the dominating characteristics of the full model and produces sufficiently accurate solutions. One of the major tasks in the development of the reduced model is the selection of snapshots which are used to determine the dominant eigenvectors. This paper discusses ways to optimize the snapshot selection. Additionally, the paper also discusses applications of the reduced model to parameter estimation, Monte Carlo simulation and experimental design in groundwater modeling.
The Airframe Noise Reduction Challenge
NASA Technical Reports Server (NTRS)
Lockhard, David P.; Lilley, Geoffrey M.
2004-01-01
The NASA goal of reducing external aircraft noise by 10 dB in the near-term presents the acoustics community with an enormous challenge. This report identifies technologies with the greatest potential to reduce airframe noise. Acoustic and aerodynamic effects will be discussed, along with the likelihood of industry accepting and implementing the different technologies. We investigate the lower bound, defined as noise generated by an aircraft modified with a virtual retrofit capable of eliminating all noise associated with the high lift system and landing gear. However, the airframe noise of an aircraft in this 'clean' configuration would only be about 8 dB quieter on approach than current civil transports. To achieve the NASA goal of 10 dB noise reduction will require that additional noise sources be addressed. Research shows that energy in the turbulent boundary layer of a wing is scattered as it crosses trailing edge. Noise generated by scattering is the dominant noise mechanism on an aircraft flying in the clean configuration. Eliminating scattering would require changes to much of the aircraft, and practical reduction devices have yet to receive serious attention. Evidence suggests that to meet NASA goals in civil aviation noise reduction, we need to employ emerging technologies and improve landing procedures; modified landing patterns and zoning restrictions could help alleviate aircraft noise in communities close to airports.
Model reduction by manifold boundaries.
Transtrum, Mark K; Qiu, Peng
2014-08-29
Understanding the collective behavior of complex systems from their basic components is a difficult yet fundamental problem in science. Existing model reduction techniques are either applicable under limited circumstances or produce "black boxes" disconnected from the microscopic physics. We propose a new approach by translating the model reduction problem for an arbitrary statistical model into a geometric problem of constructing a low-dimensional, submanifold approximation to a high-dimensional manifold. When models are overly complex, we use the observation that the model manifold is bounded with a hierarchy of widths and propose using the boundaries as submanifold approximations. We refer to this approach as the manifold boundary approximation method. We apply this method to several models, including a sum of exponentials, a dynamical systems model of protein signaling, and a generalized Ising model. By focusing on parameters rather than physical degrees of freedom, the approach unifies many other model reduction techniques, such as singular limits, equilibrium approximations, and the renormalization group, while expanding the domain of tractable models. The method produces a series of approximations that decrease the complexity of the model and reveal how microscopic parameters are systematically "compressed" into a few macroscopic degrees of freedom, effectively building a bridge between the microscopic and the macroscopic descriptions. PMID:25216014
Photochemical reduction of uranyl nitrate
Duerksen, W.K.
1993-10-20
The photochemical reduction of uranyl nitrate solutions to tetravalent uranium was investigated as a means of producing uranium dioxide feed for the saltless direct oxide reduction (SDOR) process. At high uranium concentrations, reoxidation of U{sup +4} occurs rapidly. The kinetics of the nitric oxidation of tetravalent uranium depend on the concentrations of hydrogen ion, nitrate ion, nitrous acid, and tetravalent uranium in the same manner as was reported elsewhere for the nitrate oxidation of PU{sup +3}. Reaction rate data were successfully correlated with a mechanism in which nitrogen dioxide is the reactive intermediate. Addition of a nitrous acid scavenger suppresses the reoxidation reaction. An immersion reactor employing a mercury vapor lamp gave reduction times fast enough for routine production usage. Precipitation techniques for conversion of aqueous U(NO{sub 3}){sub 4} to hydrous UO{sub 2} were evaluated. Prolonged dewatering times tended to make the process time consuming. Use of 3- to 4-M aqueous NaOH gave the best dewatering times observed. Reoxidation of the UO{sub 2} by water of hydration was encountered, which required the drying process to be carried out under a reducing atmosphere.
Model Reduction by Manifold Boundaries
Transtrum, Mark K.; Qiu, Peng
2015-01-01
Understanding the collective behavior of complex systems from their basic components is a difficult yet fundamental problem in science. Existing model reduction techniques are either applicable under limited circumstances or produce “black boxes” disconnected from the microscopic physics. We propose a new approach by translating the model reduction problem for an arbitrary statistical model into a geometric problem of constructing a low-dimensional, submanifold approximation to a high-dimensional manifold. When models are overly complex, we use the observation that the model manifold is bounded with a hierarchy of widths and propose using the boundaries as submanifold approximations. We refer to this approach as the manifold boundary approximation method. We apply this method to several models, including a sum of exponentials, a dynamical systems model of protein signaling, and a generalized Ising model. By focusing on parameters rather than physical degrees of freedom, the approach unifies many other model reduction techniques, such as singular limits, equilibrium approximations, and the renormalization group, while expanding the domain of tractable models. The method produces a series of approximations that decrease the complexity of the model and reveal how microscopic parameters are systematically “compressed” into a few macroscopic degrees of freedom, effectively building a bridge between the microscopic and the macroscopic descriptions. PMID:25216014
A Klein-Gordon acoustic theory
Anno, P.D.
1992-12-01
Geophysicists do not associate traveltime variation with density variation in acoustic or elastic wavefield interpretation. Rather, given a constant index of refraction, density variation within the medium of propagation is associated only with amplitudes. This point of view prevails because density does not occur as a variable in classical results such as Snell's Law or the eikonal equation. Nevertheless, in this paper I predict, analytically, a continuum of density effects on acoustic wavefields-including a dispersive traveltime delay when density variation is rapid. I also examine the ability of a common imaging algorithm to cope with this time delay.
A Klein-Gordon acoustic theory
Anno, P.D.
1992-12-01
Geophysicists do not associate traveltime variation with density variation in acoustic or elastic wavefield interpretation. Rather, given a constant index of refraction, density variation within the medium of propagation is associated only with amplitudes. This point of view prevails because density does not occur as a variable in classical results such as Snell`s Law or the eikonal equation. Nevertheless, in this paper I predict, analytically, a continuum of density effects on acoustic wavefields-including a dispersive traveltime delay when density variation is rapid. I also examine the ability of a common imaging algorithm to cope with this time delay.
Holography and hydrodynamics for EMD theory with two Maxwell fields
NASA Astrophysics Data System (ADS)
Smolic, Milena
2013-03-01
We use `generalized dimensional reduction' to relate a specific Einstein-Max-well-Dilaton (EMD) theory, including two gauge fields, three neutral scalars and an axion, to higher-dimensional AdS gravity (with no higher-dimensional Maxwell field). In general, this is a dimensional reduction over compact Einstein spaces in which the dimension of the compact space is continued to non-integral values. Specifically, we perform a non-diagonal Kaluza-Klein (KK) reduction over a torus, involving two KK gauge fields. Our aim is to determine the holographic dictionary and hydrodynamic behaviour of the lower-dimensional theory by performing the generalized dimensional reduction on AdS. We study a specific example of a black brane carrying a wave, whose universal sector is described by gravity coupled to two Maxwell fields, three neutral scalars and an axion, and compute the first order transport coefficients of the dual theory. In these theories {{widehat{ζ}}_s}/widehat{η}<2( {1/( {d-1} )-widehat{c}_s^2} ) , where {{widehat{c}}_s} is the speed of sound, violating a conjectured bound, but an alternative bound is satisfied.
Supersonic jet shock noise reduction
NASA Technical Reports Server (NTRS)
Stone, J. R.
1984-01-01
Shock-cell noise is identified to be a potentially significant problem for advanced supersonic aircraft at takeoff. Therefore NASA conducted fundamental studies of the phenomena involved and model-scale experiments aimed at developing means of noise reduction. The results of a series of studies conducted to determine means by which supersonic jet shock noise can be reduced to acceptable levels for advanced supersonic cruise aircraft are reviewed. Theoretical studies were conducted on the shock associated noise of supersonic jets from convergent-divergent (C-D) nozzles. Laboratory studies were conducted on the influence of narrowband shock screech on broadband noise and on means of screech reduction. The usefulness of C-D nozzle passages was investigated at model scale for single-stream and dual-stream nozzles. The effect of off-design pressure ratio was determined under static and simulated flight conditions for jet temperatures up to 960 K. Annular and coannular flow passages with center plugs and multi-element suppressor nozzles were evaluated, and the effect of plug tip geometry was established. In addition to the far-field acoustic data, mean and turbulent velocity distributions were measured with a laser velocimeter, and shadowgraph images of the flow field were obtained.
Mesotherapy for local fat reduction.
Jayasinghe, S; Guillot, T; Bissoon, L; Greenway, F
2013-10-01
Mesotherapy, which is the injection of substances locally into mesodermally derived subcutaneous tissue, developed from empirical observations of a French physician in the 1950s. Although popular in Europe for many medical purposes, it is used for local cosmetic fat reduction in the United States. This paper reviews manuscripts indexed in PubMed/MEDLINE under 'mesotherapy', which pertains to local fat reduction. The history of lipolytic mesotherapy, the physiology of body fat distribution, the mechanism of action of different lipolytic stimulators and their increased efficacy in combination are reviewed. Mesotherapy falls into two categories. Lipolytic mesotherapy using lipolytic stimulators requires more frequent treatments as the fat cells are not destroyed and can refill over time. Ablative mesotherapy destroys fat cells with a detergent, causes inflammation and scarring from the fat necrosis, but requires fewer treatments. The historic and empiric mixing of sodium channel blocking local anaesthetics in mesotherapy solutions inhibits the intended lipolysis. Major mesotherapy safety concerns include injection site infections from poor sterile technique. Cosmetic mesotherapy directs the area from which fat is lost to improve self-image. Studies were of relatively small number, many with limited sample sizes. Future research should be directed towards achieving a Food and Drug Administration indication rather than continuing expansion of off-label use. PMID:23800269
LDRD report nonlinear model reduction
Segalman, D.; Heinstein, M.
1997-09-01
The very general problem of model reduction of nonlinear systems was made tractable by focusing on the very large subclass consisting of linear subsystems connected by nonlinear interfaces. Such problems constitute a large part of the nonlinear structural problems encountered in addressing the Sandia missions. A synthesis approach to this class of problems was developed consisting of: detailed modeling of the interface mechanics; collapsing the interface simulation results into simple nonlinear interface models; constructing system models by assembling model approximations of the linear subsystems and the nonlinear interface models. These system models, though nonlinear, would have very few degrees of freedom. A paradigm problem, that of machine tool vibration, was selected for application of the reduction approach outlined above. Research results achieved along the way as well as the overall modeling of a specific machine tool have been very encouraging. In order to confirm the interface models resulting from simulation, it was necessary to develop techniques to deduce interface mechanics from experimental data collected from the overall nonlinear structure. A program to develop such techniques was also pursued with good success.
Comparison of noise reduction systems
NASA Astrophysics Data System (ADS)
Noel, S. D.; Whitaker, R. W.
1991-06-01
When using infrasound as a tool for verification, the most important measurement to determine yield has been the peak-to-peak pressure amplitude of the signal. Therefore, there is a need to operate at the most favorable signal-to-noise ratio (SNR) possible. Winds near the ground can degrade the SNR, thereby making accurate signal amplitude measurement difficult. Wind noise reduction techniques were developed to help alleviate this problem; however, a noise reducing system should reduce the noise, and should not introduce distortion of coherent signals. An experiment is described to study system response for a variety of noise reducing configurations to a signal generated by an underground test (UGT) at the Nevada Test Site (NTS). In addition to the signal, background noise reduction is examined through measurements of variance. Sensors using two particular geometries of noise reducing equipment, the spider and the cross appear to deliver the best SNR. Because the spider configuration is easier to deploy, it is now the most commonly used.
Reduction of nitrate in Shewanella
Gao, Haichun; Yang, Zamin Koo; Barua, Sumitra; Reed, SB; Nealson, Kenneth H.; Fredrikson, JK; Tiedje, James; Zhou, Jizhong
2009-01-01
In the genome of Shewanella oneidensis, a napDAGHB gene cluster encoding periplasmic nitrate reductase (NapA) and accessory proteins and an nrfA gene encoding periplasmic nitrite reductase (NrfA) have been identified. These two systems seem to be atypical because the genome lacks genes encoding cytoplasmic membrane electron transport proteins, NapC for NAP and NrfBCD/NrfH for NRF, respectively. Here, we present evidence that reduction of nitrate to ammonium in S. oneidensis is carried out by these atypical systems in a two-step manner. Transcriptional and mutational analyses suggest that CymA, a cytoplasmic membrane electron transport protein, is likely to be the functional replacement of both NapC and NrfH in S. oneidensis. Surprisingly, a strain devoid of napB encoding the small subunit of nitrate reductase exhibited the maximum cell density sooner than the wild type. Further characterization of this strain showed that nitrite was not detected as a free intermediate in its culture and NapB provides a fitness gain for S. oneidensis to compete for nitrate in the environments. On the basis results from mutational analyses of napA, napB, nrfA and napBnrfA in-frame deletion mutants, we propose that NapB is able to favor nitrate reduction by routing electrons to NapA exclusively.
Bieda, J.A.
1995-12-01
Btu reduction in gas plants refers to the measurable amount of energy removed from the gas stream during processing. The unit of measure is the {open_quotes}Btu{close_quotes} (British thermal unit) and it can be calculated for any gas stream by measuring the volume and analyzing the composition. The Btu`s removed in processing represent the gas components converted to natural gas liquids (NGL`s), the fuel burned to effect the gas-phase-to-liquid-phase conversion, and any unmeasured losses between the plant`s inlet meter and residue meter. The sum total of these components is referred to as Plant Btu Reduction, or {open_quotes}PBR{close_quotes}. PBR plays a key role in the plant`s profitability, appearing as the single greatest debit on the plant`s balance sheet. Accordingly, it is critical that the contributing elements are measured accurately. This paper will further attempt to explain the significance of PBR and to demonstrate its calculation.
Pilot-scale tests were conducted to develop a combined nitrogen oxide (NOx) reduction technology using both selective catalytic reduction (SCR) and selective noncatalytic reduction (SNCR). A commercially available vanadium-and titatnium-based composite honeycomb catalyst and enh...
PARTICULATE DATA REDUCTION SYSTEM (PADRE) USER GUIDE
The report, a user guide, describes the capabilities and use of the Particulate Data Reduction (PADRE) system, an interactive computer program that facilitates entry, reduction, and analysis of cascade impactor data for particle size distributions. Example sessions are provided t...
50 CFR 600.1007 - Reduction amendments.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Reduction amendments. 600.1007 Section 600.1007 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC....1007 Reduction amendments. (a) Each reduction amendment may contain provisions that are...
Model reduction methods for control design
NASA Technical Reports Server (NTRS)
Dunipace, K. R.
1988-01-01
Several different model reduction methods are developed and detailed implementation information is provided for those methods. Command files to implement the model reduction methods in a proprietary control law analysis and design package are presented. A comparison and discussion of the various reduction techniques is included.
20 CFR 229.65 - Initial reduction.
Code of Federal Regulations, 2011 CFR
2011-04-01
... Employees' Benefits RAILROAD RETIREMENT BOARD REGULATIONS UNDER THE RAILROAD RETIREMENT ACT SOCIAL SECURITY..., State, or Local Law or Plan § 229.65 Initial reduction. (a) When reduction is effective. A benefit... under a Federal, State, or local law or plan (public disability benefit). The reduction is...
Selected reprints on dataflow and reduction architectures
Thakkar, S.S.
1987-01-01
This reprint collection looks at alternatives to von Neumann architecture: dataflow and reduction architectures and is organized into eight chapters that cover: different dataflow systems; dataflow solution to multiprocessing; dataflow languages and dataflow graphs; functional programming languages and their implementation; uniprocessor architectures that provide support for reduction; parallel graph reduction machines, and hybrid multiprocessor architectures.
75 FR 76345 - Risk Reduction Program
Federal Register 2010, 2011, 2012, 2013, 2014
2010-12-08
...The Rail Safety Improvement Act of 2008 requires the development and implementation of railroad safety risk reduction programs. Risk reduction is a comprehensive, system-oriented approach to safety that determines an operation's level of risk by identifying and analyzing applicable hazards and develops plans to mitigate that risk. Each Risk Reduction Program (RRP) is statutorily required to be......
24 CFR 35.320 - Hazard reduction.
Code of Federal Regulations, 2010 CFR
2010-04-01
... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Hazard reduction. 35.320 Section 35... Provided by a Federal Agency Other Than HUD § 35.320 Hazard reduction. Each owner shall conduct interim controls consistent with the findings of the risk assessment report. Hazard reduction shall be conducted...
Ultrasound-Assisted Distal Radius Fracture Reduction
Socransky, Steve; Skinner, Andrew; Bromley, Mark; Smith, Andrew; Anawati, Alexandre; Middaugh, Jeff; Ross, Peter
2016-01-01
Introduction Closed reduction of distal radius fractures (CRDRF) is a commonly performed emergency department (ED) procedure. The use of point-of-care ultrasound (PoCUS) to diagnose fractures and guide reduction has previously been described. The primary objective of this study was to determine if the addition of PoCUS to CRDRF changed the perception of successful initial reduction. This was measured by the rate of further reduction attempts based on PoCUS following the initial clinical determination of achievement of best possible reduction. Methods We performed a multicenter prospective cohort study, using a convenience sample of adult ED patients presenting with a distal radius fracture to five Canadian EDs. All study physicians underwent standardized PoCUS training for fractures. Standard clinically-guided best possible fracture reduction was initially performed. PoCUS was then used to assess the reduction adequacy. Repeat reduction was performed if deemed indicated. A post-reduction radiograph was then performed. Clinician impression of reduction adequacy was scored on a 5 point Likert scale following the initial clinically-guided reduction and following each PoCUS scan and the post-reduction radiograph. Results There were 131 patients with 132 distal radius fractures. Twelve cases were excluded prior to analysis. There was no significant difference in the assessment of the initial reduction status by PoCUS as compared to the clinical exam (mean score: 3.8 vs. 3.9; p = 0.370; OR 0.89; 95% CI 0.46 to 1.72; p = 0.87). Significantly fewer cases fell into the uncertain category with PoCUS than with clinical assessment (2 vs 12; p = 0.008). Repeat reduction was performed in 49 patients (41.2%). Repeat reduction led to a significant improvement (p < 0.001) in the PoCUS determined adequacy of reduction (mean score: 4.3 vs 3.1; p < 0.001). In this group, the odds ratio for adequate vs. uncertain or inadequate reduction assessment using PoCUS was 12.5 (95% CI 3
Ultrasound-Assisted Distal Radius Fracture Reduction.
Socransky, Steve; Skinner, Andrew; Bromley, Mark; Smith, Andrew; Anawati, Alexandre; Middaugh, Jeff; Ross, Peter; Atkinson, Paul
2016-01-01
Introduction Closed reduction of distal radius fractures (CRDRF) is a commonly performed emergency department (ED) procedure. The use of point-of-care ultrasound (PoCUS) to diagnose fractures and guide reduction has previously been described. The primary objective of this study was to determine if the addition of PoCUS to CRDRF changed the perception of successful initial reduction. This was measured by the rate of further reduction attempts based on PoCUS following the initial clinical determination of achievement of best possible reduction. Methods We performed a multicenter prospective cohort study, using a convenience sample of adult ED patients presenting with a distal radius fracture to five Canadian EDs. All study physicians underwent standardized PoCUS training for fractures. Standard clinically-guided best possible fracture reduction was initially performed. PoCUS was then used to assess the reduction adequacy. Repeat reduction was performed if deemed indicated. A post-reduction radiograph was then performed. Clinician impression of reduction adequacy was scored on a 5 point Likert scale following the initial clinically-guided reduction and following each PoCUS scan and the post-reduction radiograph. Results There were 131 patients with 132 distal radius fractures. Twelve cases were excluded prior to analysis. There was no significant difference in the assessment of the initial reduction status by PoCUS as compared to the clinical exam (mean score: 3.8 vs. 3.9; p = 0.370; OR 0.89; 95% CI 0.46 to 1.72; p = 0.87). Significantly fewer cases fell into the uncertain category with PoCUS than with clinical assessment (2 vs 12; p = 0.008). Repeat reduction was performed in 49 patients (41.2%). Repeat reduction led to a significant improvement (p < 0.001) in the PoCUS determined adequacy of reduction (mean score: 4.3 vs 3.1; p < 0.001). In this group, the odds ratio for adequate vs. uncertain or inadequate reduction assessment using PoCUS was 12.5 (95% CI 3
Continuous reduction of uranium tetrafluoride
DeMint, A.L.; Maxey, A.W.
1993-10-21
Operation of a pilot-scale system for continuous metallothermic reduction of uranium tetrafluoride (UF{sub 4} or green salt) has been initiated. This activity is in support of the development of a cost- effective process to produce uranium-iron (U-Fe) alloy feed for the Uranium-Atomic Vapor Laser Isotope Separation (U-AVLIS) program. To date, five runs have been made to reduce green salt (UF{sub 4}) with magnesium. During this quarter, three runs were made to perfect the feeding system, examine feed rates, and determine the need for a crust breaker/stirrer. No material was drawn off in any of the runs; both product metal and by-product salt were allowed to accumulate in the reactor.
Phase width reduction project summary
Clark, D.J.; Xie, Z.Q.; McMahan, M. A.
1999-11-01
The purpose of the phase width reduction project, 1993--96, was to reduce the phase width of the 88-Inch Cyclotron beam on target from 5--10 ns to 1--2 ns for certain experiments, such as Gammasphere, which use time-of-flight identification. Since reducing the phase width also reduces beam intensity, tuning should be done to also optimize the transmission. The Multi-turn Collimator slits in the cyclotron center region were used to collimate the early turns radially, thus reducing the phase width from about 5 ns to 1--2 ns FWHM for a Gammasphere beam. The effect of the slits on phase width was verified with a Fast Faraday Cup and with particle and gamma-ray detectors in the external beamline.
Greenhouse Gas Reductions: SF6
Anderson, Diana
2012-01-01
Argonne National Laboratory is leading the way in greenhouse gas reductions, particularly with the recapture and recycling of sulfur hexafluoride (SF6). SF6 is a gas used in industry as an anti-arcing agent. It is an extremely potent greenhouse gas — one pound of SF6 is equivalent to 12 tons of carbon dioxide. While the U.S. does not currently regulate SF6 emissions, Argonne is proactively and voluntarily recovering and recycling to reduce SF6 emissions. Argonne saves over 16,000 tons of SF6 from being emitted into the atmosphere each year, and by recycling the gas rather than purchasing it new, we save taxpayers over $208,000 each year.