Light focusing through strongly scattering media by binary amplitude modulation
Huang, Hui-ling; Sun, Cun-zhi; Chen, Zi-yang; Pu, Ji-xiong
2015-07-01
Based on the angular spectrum method and the circular Gaussian distribution (CGD) model of scattering media, we numerically simulate light focusing through strongly scattering media. A high contrast focus in the target area is produced by using feedback optimization algorithm with binary amplitude modulation. It is possible to form the focusing with one focus or multiple foci at arbitrary areas. The influence of the number of square segments of spatial light modulation on the enhancement factor of intensity is discussed. Simulation results are found to be in good agreement with theoretical analysis for light refocusing.
A class of amplitude modulating and invisible inhomogeneous media
Vial, Benjamin; Horsley, Simon A R; Philbin, Thomas G; Hao, Yang
2016-01-01
We propose a general method to arbitrarily manipulate the amplitude of an electromagnetic wave propagating in a two-dimensional medium, without introducing any scattering. This leads to a whole class of isotropic spatially varying permittivity and permeability profiles that are invisible while shaping the field magnitude. In addition, we propose a metamaterial structure working in the infrared that demonstrates deep sub-wavelength control of the electric field amplitude and strong reduction of the scattering. This work offers an alternative strategy to achieve invisibility with isotropic materials and paves the way for tailoring the propagation of light at the nanoscale.
Riesgos antrópicos generados por la actividad minera
Ana Violeta Argüello Mejía; Enriqueta Cantos Aguirre; Jorge Vitery Moya
2013-01-01
Las actividades productivas generan riesgos antrópicos [1] a mediano y largo plazo. La zona de estudio se ubica en las Parroquias de Pomasqui, San Antonio y Calacalí, donde se han producido riesgos debido a las actividades humanas, en este caso, por la explotación de las canteras para abastecer el mercado de la construcción del Distrito Metropolitano de Quito. La investigación propone determinar los riesgos antrópicos generados por la actividad minera. Los pobladores de la zona identifican qu...
Contenido generado por usuarios (UGC, wikis y derecho de autor
Directory of Open Access Journals (Sweden)
Juan Sebastián Sereno Restrepo
2010-11-01
Full Text Available El contenido generado mediante wiki por sus usuarios plantea dos problemas. El primero (“formal”, establecer a qué figura de atribución y coordinación de facultades de derecho de autor corresponde; el segundo (“deontológico”, determinar si los jurídicos efectos derivados de tal adecuación son consistentes con una de las finalidades legitimadoras del derecho de autor (incentivar la creación, y en caso negativo, qué mecanismo se debe utilizar para resolver la contradicción. El contenido generado mediante wiki (abierta corresponde, por regla general, a la figura de obra originaria y derivada; adicionalmente, los efectos jurídicos derivados no son claramente compatibles con la promoción de la creación. Tal contradicción se resuelve implementando en la wiki una licencia general (vinculante para todos usuarios de la wiki, estándar y uniforme (vr. g., la licencia creative commons.
Riesgos antrópicos generados por la actividad minera
Directory of Open Access Journals (Sweden)
Ana Violeta Argüello Mejía
2013-10-01
Full Text Available Las actividades productivas generan riesgos antrópicos [1] a mediano y largo plazo. La zona de estudio se ubica en las Parroquias de Pomasqui, San Antonio y Calacalí, donde se han producido riesgos debido a las actividades humanas, en este caso, por la explotación de las canteras para abastecer el mercado de la construcción del Distrito Metropolitano de Quito. La investigación propone determinar los riesgos antrópicos generados por la actividad minera. Los pobladores de la zona identifican que la minería artesanal en sus inicios constituyó una fuente de trabajo, donde sus familias también se involucraban. Actualmente, se observa que en la mayoría de las canteras se utiliza maquinaria especializada y no participan los trabajadores de la zona. Los taludes de las canteras son de 80o y 90o grados, generando amenazas para los trabajadores y moradores de las viviendas aledañas. Uno de los mayores impactos es la contaminación del aire, sin embargo, el suelo y los cursos de agua están siendo afectados por los desperdicios que produce la actividad minera. La población, que está expuesta permanentemente al polvo ocasionado por las canteras y al transporte de material, acusa enfermedades de tipo respiratorio. Así mismo, el ruido ocasionado por el transporte constituye una molestia constante para los pobladores.
Loizou, C. P.; Murray, V.; Pattichis, M. S.; Pantziaris, M.; Nicolaides, A. N.; Pattichis, C. S.
2014-01-01
The intima-media thickness (IMT) of the common carotid artery (CCA) is widely used as an early indicator of cardiovascular disease (CVD). Typically, the IMT grows with age and this is used as a sign of increased risk of CVD. Beyond thickness, there is also clinical interest in identifying how the composition and texture of the intima-media complex (IMC) changed and how these textural changes grow into atherosclerotic plaques that can cause stroke. Clearly though texture analysis of ultrasound images can be greatly affected by speckle noise, our goal here is to develop effective despeckle noise methods that can recover image texture associated with increased rates of atherosclerosis disease. In this study, we perform a comparative evaluation of several despeckle filtering methods, on 100 ultrasound images of the CCA, based on the extracted multiscale Amplitude-Modulation Frequency-Modulation (AM-FM) texture features and visual image quality assessment by two clinical experts. Texture features were extracted from the automatically segmented IMC for three different age groups. The despeckle filters hybrid median and the homogeneous mask area filter showed the best performance by improving the class separation between the three age groups and also yielded significantly improved image quality. PMID:24734038
Campo magnético generado por N bobinas alineadas axialmente
Directory of Open Access Journals (Sweden)
César Gutiérrez Tapia
2002-01-01
Full Text Available El cálculo del campo magnético generado por n bobinas axialmente alineadas permanece como un importante problema técnico en el proceso de construcción de los diferentes dispositivos para confinar el plasma con perfiles de campo externo tipo espejo. A partir de los métodos numéricos existentes para el cálculo de las integrales elípticas de primera clase k y segunda clase e, se describe la obtención de expresiones simples para calcular el campo magnético por el método de las ecuaciones elípticas.
Valorización de los residuos generados en el procesado de aceites vegetales usados
Directory of Open Access Journals (Sweden)
Dolores Hidalgo-Barrio
2014-01-01
Full Text Available Se han investigado las ventajas de un sistema de digestión anaerobia en dos fases para el tratamiento de una mezcla de los residuos oleosos (RO generados en el procesado de aceites vegetales usados y purín porcino (PP, 1/5 v/v, utilizando dos digestores semi-continuos operados a 37±1 ºC. Los experimentos fueron llevados a cabo a tiempos hidráulicos de residencia (THR de 0.5, 1, 2 y 4 días en la primera etapa (reactor acidogénico y de 11.5, 15, 18 y 20 días en la segunda etapa (reactor metanogénico. Los resultados revelaron que el THR tiene una gran influencia en la eliminación de demanda química de oxígeno soluble (DQOs y sólidos disueltos totales (SDT. La máxima eficiencia de eliminación de DQOs, SDT y producción máxima de biogás fueron de 86.4% y 81.9% y 0.65 m3 biogás por kilogramo de sólido disuelto volátil (SDV eliminado (65% CH4 respectivamente, conseguidas todas a un THR total de 20 días.
Influencia de Las Cargas Térmicas Sobre Flujos de Aire Generados en Una Habitacíon
DEFF Research Database (Denmark)
Olmedo, Inés; Ruiz de Adana Santiago, Manuel; Nielsen, Peter V.
2011-01-01
El flujo de aire en el interior de un local generado con un sistema de ventilación y difusión de aire puede verse afectado por las cargas térmicas internas del local. En este trabajo, se estudia la influencia de las cargas térmicas internas debidas a personas en el flujo de aire interior de un lo...
Amplitude mediated chimera states
Sethia, Gautam C.; Sen, Abhijit; Johnston, George L.
2013-01-01
We investigate the possibility of obtaining chimera state solutions of the non-local Complex Ginzburg-Landau Equation (NLCGLE) in the strong coupling limit when it is important to retain amplitude variations. Our numerical studies reveal the existence of a variety of amplitude mediated chimera states (including stationary and non-stationary two cluster chimera states), that display intermittent emergence and decay of amplitude dips in their phase incoherent regions. The existence regions of t...
Periods and Feynman amplitudes
Brown, Francis
2016-01-01
Feynman amplitudes in perturbation theory form the basis for most predictions in particle collider experiments. The mathematical quantities which occur as amplitudes include values of the Riemann zeta function and relate to fundamental objects in number theory and algebraic geometry. This talk reviews some of the recent developments in this field, and explains how new ideas from algebraic geometry have led to much progress in our understanding of amplitudes. In particular, the idea that certain transcendental numbers, such as $\\pi$, can be viewed as a representation of a group, provides a powerful framework to study amplitudes which reveals many hidden structures.
Energy Technology Data Exchange (ETDEWEB)
Flohr, Michael [Physikalisches Institut, University of Bonn, Nussallee 12, D-53115 Bonn (Germany); Gaberdiel, Matthias R [Institut fuer Theoretische Physik, ETH Zuerich, ETH-Hoenggerberg, 8093 Zurich (Switzerland)
2006-02-24
For the example of the logarithmic triplet theory at c = -2, the chiral vacuum torus amplitudes are analysed. It is found that the space of these torus amplitudes is spanned by the characters of the irreducible representations, as well as a function that can be associated with the logarithmic extension of the vacuum representation. A few implications and generalizations of this result are discussed.
Amplitudes, acquisition and imaging
Energy Technology Data Exchange (ETDEWEB)
Bloor, Robert
1998-12-31
Accurate seismic amplitude information is important for the successful evaluation of many prospects and the importance of such amplitude information is increasing with the advent of time lapse seismic techniques. It is now widely accepted that the proper treatment of amplitudes requires seismic imaging in the form of either time or depth migration. A key factor in seismic imaging is the spatial sampling of the data and its relationship to the imaging algorithms. This presentation demonstrates that acquisition caused spatial sampling irregularity can affect the seismic imaging and perturb amplitudes. Equalization helps to balance the amplitudes, and the dealing strategy improves the imaging further when there are azimuth variations. Equalization and dealiasing can also help with the acquisition irregularities caused by shot and receiver dislocation or missing traces. 2 refs., 2 figs.
Amplitude recruitment of cochlear potential
Institute of Scientific and Technical Information of China (English)
LI Xingqi; SUN Wei; SUN Jianhe; YU Ning; JIANG Sichang
2001-01-01
Intracellular recordings were made from outer hair cells (OHC) and the cochlear microphonics (CM) were recorded from scala media (SM) in three turn of guinea pig cochlea,the compound action potential (CAP) were recorded at the round window (RW) before and after the animal were exposed to white noise. The results suggest that the nonlinear properties with “saduration” of Input/output (I/O) function of OHC AC recepter potential and CM were founded; the nonlinear properties with “Low”, “Platean” and “high” of CAP also were investigated. After explosion, the threshold shift of CAP has about 10 dB. The I/O of OHC responses and CM were changed in a linearizing (i.e., nonlinearity loss), the “platean” of I/O CAP disappeared and the growth rate of CAP amplitude were larger than before explosion. The response amplitude recruitment of OHC appears to result from reduction in gain (i.e., hearing loss); It was due to the nonlinear growth function of OHC receptor potentials was changed in linearzing that the basilar membrance motion was changed in linearizing. Since intensity coding in the inner ear depends on an interactions of nonlinear basilar membrance and nerve fibers. So that it must lead to a linearizing of CAP as input responses.
Protostring Scattering Amplitudes
Thorn, Charles B
2016-01-01
We calculate some tree level scattering amplitudes for a generalization of the protostring, which is a novel string model implied by the simplest string bit models. These bit models produce a lightcone worldsheet which supports $s$ integer moded Grassmann fields. In the generalization we supplement this Grassmann worldsheet system with $d=24-s$ transverse coordinate worldsheet fields. The protostring corresponds to $s=24$ and the bosonic string to $s=0$. The interaction vertex is a simple overlap with no operator insertions at the break/join point. Assuming that $s$ is even we calculate the multi-string scattering amplitudes by bosonizing the Grassmann fields, each pair equivalent to one compactified bosonic field, and applying Mandelstam's interacting string formalism to a system of $s/2$ compactified and $d$ uncompactified bosonic worldsheet fields. We obtain all amplitudes for open strings with no oscillator excitations and for closed strings with no oscillator excitations and zero winding number. We then ...
Aplicación de técnicas de minería de datos a los log generados por CATEDU
Buera Corchón, Ricardo
2012-01-01
Extracción de conocimiento de los log generados por un servidor web aplicando técnicas de minería de datos. Extracció de coneixement dels log generats per un servidor web aplicant tècniques de mineria de dades.
Light Meson Distribution Amplitudes
Arthur, R; Brommel, D; Donnellan, M A; Flynn, J M; Juttner, A; de Lima, H Pedroso; Rae, T D; Sachrajda, C T; Samways, B
2010-01-01
We calculated the first two moments of the light-cone distribution amplitudes for the pseudoscalar mesons ($\\pi$ and $K$) and the longitudinally polarised vector mesons ($\\rho$, $K^*$ and $\\phi$) as part of the UKQCD and RBC collaborations' $N_f=2+1$ domain-wall fermion phenomenology programme. These quantities were obtained with a good precision and, in particular, the expected effects of $SU(3)$-flavour symmetry breaking were observed. Operators were renormalised non-perturbatively and extrapolations to the physical point were made, guided by leading order chiral perturbation theory. The main results presented are for two volumes, $16^3\\times 32$ and $24^3\\times 64$, with a common lattice spacing. Preliminary results for a lattice with a finer lattice spacing, $32^3\\times64$, are discussed and a first look is taken at the use of twisted boundary conditions to extract distribution amplitudes.
Periods and Superstring Amplitudes
Stieberger, S
2016-01-01
Scattering amplitudes which describe the interaction of physical states play an important role in determining physical observables. In string theory the physical states are given by vibrations of open and closed strings and their interactions are described (at the leading order in perturbation theory) by a world-sheet given by the topology of a disk or sphere, respectively. Formally, for scattering of N strings this leads to N-3-dimensional iterated real integrals along the compactified real axis or N-3-dimensional complex sphere integrals, respectively. As a consequence the physical observables are described by periods on M_{0,N} - the moduli space of Riemann spheres of N ordered marked points. The mathematical structure of these string amplitudes share many recent advances in arithmetic algebraic geometry and number theory like multiple zeta values, single-valued multiple zeta values, Drinfeld, Deligne associators, Hopf algebra and Lie algebra structures related to Grothendiecks Galois theory. We review the...
HIGH AMPLITUDE PROPAGATED CONTRACTIONS
Bharucha, Adil E.
2012-01-01
While most colonic motor activity is segmental and non-propulsive, colonic high amplitude propagated contractions (HAPC) can transfer colonic contents over long distances and often precede defecation. HAPC occur spontaneously, in response to pharmacological agents or colonic distention. In this issue of Neurogastroenterology and Motility, Rodriguez and colleagues report that anal relaxation during spontaneous and bisacodyl-induced HAPC exceeds anal relaxation during rectal distention in const...
Directory of Open Access Journals (Sweden)
Leadina Sánchez Barboza
2015-06-01
Full Text Available La valoración de impactos ambientales está sujeta a imprecisión, vaguedad y subjetividad. Estas características son extensivas al impacto generado por la presencia de contaminantes emergentes -fármacos- en aguas residuales hospitalarias, por lo que este trabajo propone valorar el impacto de dichos contaminantes mediante un sistema de inferencia borrosa, utilizando el toolbox fuzzy logic de MATLAB®, aplicando el sistema experto Mamdani. Los conjuntos borrosos de entrada se establecieron a partir de las concentraciones de los fármacos mediante variables lingüísticas definidas por medio de funciones de pertenencia trapezoidales, y el conjunto borroso de salida comprende la magnitud del impacto definida a través de una función de pertenencia triangular. Posteriormente, se obtuvo una valoración (en escala de 0 a 100 para concentraciones de fármacos máximas y promedios presentes en el agua residual, y por último, con estos valores se determina la magnitud del impacto ambiental a través del sistema de inferencia borrosa diseñado. El tratamiento borroso es útil para valorar los impactos ambientales en aguas residuales de contaminantes emergentes como los compuestos farmacéuticos.
Salvioli, Mónica L.; Colli, Gustavo A.; Jelinski, Guillermo; Banzatto, Luciana
2011-01-01
Este proyecto de extensión surge como resultado de una serie de actividades que la UIDD Gestión Ambiental inicia en el año 2008 con relación a la gestión interna de los residuos sólidos urbanos (RSU) generados en su ámbito de trabajo, mediante reducción, reutilización y disposición inicial diferenciada de los mismos.
Closed string amplitudes as single-valued open string amplitudes
International Nuclear Information System (INIS)
We show that the single trace heterotic N-point tree-level gauge amplitude ANHET can be obtained from the corresponding type I amplitude ANI by the single-valued (sv) projection: ANHET=sv(ANI). This projection maps multiple zeta values to single-valued multiple zeta values. The latter represent a subclass of multiple zeta values originating from single-valued multiple polylogarithms at unity. Similar relations between open and closed string amplitudes or amplitudes of different string vacua can be established. As a consequence the α′-expansion of a closed string amplitude is dictated by that of the corresponding open string amplitude. The combination of single-valued projections, Kawai–Lewellen–Tye relations and Mellin correspondence reveal a unity of all tree-level open and closed superstring amplitudes together with the maximally supersymmetric Yang–Mills and supergravity theories
CHY formula and MHV amplitudes
Du, Yi-jian; Wu, Yong-shi
2016-01-01
In this paper, we study the relation between the Cachazo-He-Yuan (CHY) formula and the maximal-helicity-violating (MHV) amplitudes of Yang-Mills and gravity in four dimensions. We prove that only one special rational solution of the scattering equations found by Weinzierl support the MHV amplitudes. Namely, localized at this solution, the integrated CHY formula reproduces the Parke-Taylor formula for Yang-Mills amplitudes as well as the Hodges formula for gravitational amplitudes. This is achieved by developing techniques, in a manifestly M\\"obius covariant formalism, to explicitly compute relevant reduced Pfaffians/determinants. We observe and prove two interesting properties (or identities), which facilitate the computations. We also check that all the other $(n-3)!-1$ solutions to the scattering equations do not support the MHV amplitudes, and prove analytically that this is indeed true for the other special rational solution proposed by Weinzierl, that actually supports the anti-MHV amplitudes.
Hidden Beauty in Multiloop Amplitudes
Cachazo, Freddy(Perimeter Institute for Theoretical Physics, Waterloo, Ontario, Canada); Spradlin, Marcus; Volovich, Anastasia
2006-01-01
Planar L-loop maximally helicity violating amplitudes in N = 4 supersymmetric Yang-Mills theory are believed to possess the remarkable property of satisfying iteration relations in L. We propose a simple new method for studying the iteration relations for four-particle amplitudes which involves the use of certain linear differential operators and eliminates the need to fully evaluate any loop integrals. We carry out this procedure in explicit detail for the two-loop amplitude and argue that t...
Amplitude oscillation of DCLC mode
International Nuclear Information System (INIS)
A quasilinear model and a simulation code taking into account the electron bounce resonance damping have been developed to describe the amplitude oscillation of the drift cyclotron loss-cone mode, which has been observed in mirror experiments. It was found that this oscillatory behavior of the amplitude is caused by the temporal variation of the growth rate and the effect of electron bounce resonance damping on the amplitude of this mode. (author)
Motivic amplitudes and cluster coordinates
J.K. Golden; Goncharov, A. B.; M. Spradlin; C. Vergu; Volovich, A.
2014-01-01
In this paper we study motivic amplitudes--objects which contain all of the essential mathematical content of scattering amplitudes in planar SYM theory in a completely canonical way, free from the ambiguities inherent in any attempt to choose particular functional representatives. We find that the cluster structure on the kinematic configuration space Conf_n(P^3) underlies the structure of motivic amplitudes. Specifically, we compute explicitly the coproduct of the two-loop seven-particle MH...
Directory of Open Access Journals (Sweden)
Irán Fernández-Torres
2010-01-01
Full Text Available La capacidad germicida del ozono está ampliamente reconocida, la cual está dada por su elevado poder oxidante y su rápida velocidad de reacción con diferentes moléculas biológicas. Se conocen estudios acerca de la cinética de inactivación que sigue el ozono sobre los microorganismos. Sin embargo, aunque se sabe que el ozono genera compuestos (subproductos al reaccionar con los microorganismos, no existen estudios sobre el posible efecto que presentan estos subproductos en el proceso de inactivación sobre aquellos microorganismos que aún permanecen viables en el medio. Luego, la información que se obtenga alrededor de este efecto puede ampliar el conocimiento sobre las dosis de ozono a aplicar en los procesos de desinfección de aguas y el mejor funcionamiento en las plantas de tratamiento. El presente trabajo evaluó los efectos oxidantes de los subproductos generados de la reacción del ozono con los microorganismos, sobre dos especies microbianas: Escherichia coli ATCC 25922 y Salmonella enterica var. thyphimurium ATCC 12048, en cuanto a viabilidad y su efecto sobre algunos componentes de la membrana plasmática. Se realizó un estudio cinético a bajas concentraciones de ozono y se determinó la actividad antimicrobiana de los subproductos de reacción. Además, se evaluó la variación de los niveles de peroxidación lipídica de los ácidos grasos insaturados presentes en la membrana plasmática. Los resultados de las cinéticas de inactivación mostraron dos constantes cinéticas para ambos microorganismos. Esto está relacionado fundamentalmente con el agotamiento del ozono disuelto desde los primeros instantes y a la actividad antimicrobiana mostrada por los subproductos de reacción, al generar muerte celular aun cuando no se detecta ozono disuelto. El ozono afectó la permeabilidad de la membrana de los microorganismos y se observó un aumento en las concentraciones de sustancias reactivas al ácido tiobarbitúrico debido a
Graviton amplitudes from collinear limits of gauge amplitudes
Stephan Stieberger; Taylor, Tomasz R.
2015-01-01
We express all tree-level graviton amplitudes in Einstein's gravity as the collinear limits of a linear combination of pure Yang–Mills amplitudes in which each graviton is represented by two gauge bosons, each of them carrying exactly one half of graviton's momentum and helicity.
Large amplitude oscillatory elongation flow
DEFF Research Database (Denmark)
Rasmussen, Henrik K.; Laillé, Philippe; Yu, Kaijia
2008-01-01
A filament stretching rheometer (FSR) was used for measuring the elongation flow with a large amplitude oscillative elongation imposed upon the flow. The large amplitude oscillation imposed upon the elongational flow as a function of the time t was defined as epsilon(t) =(epsilon) over dot(0)t...
Directory of Open Access Journals (Sweden)
Dora Ángela Hoyos
2013-06-01
Full Text Available Este artículo muestra los resultados de una investigación sobre la producción de residuos sólidos generados por las empresas Antioqueñas. Investigación que fue desarrollada por la Universidad de San Buenaventura, la Universidad de Medellín y la Universidad de Antioquia dentro del programa Expedición Antioquia 2013. Para lo cual, se evaluó la producción de residuos generados en empresas pertenecientes a las actividades económicas; agricultura, ganadería, caza y silvicultura; Explotación de minas y canteras; Industrias manufactureras y Construcción. El propósito del estudio fue conocer la tipología, cantidad e impacto ambiental de los residuos generados en el departamento en los sectores seleccionados, constituyéndose en una base para futuras investigaciones, orientadas a determinar el potencial aprovechamiento de los residuos para la elaboración de nuevos productos. La zona de estudio corresponde al 80,8% de la superficie del departamento de Antioquia, subregiones, Bajo Cauca, Nordeste, Norte, Oriente, Suroeste, Urabá y Valle de Aburrá; las cuales concentran las zonas industriales, mineras y agropecuarias más representativas del departamento, además de ser subregiones altamente pobladas con un crecimiento en infraestructura, representado en un sector de construcción fortalecido. La metodología utilizada fue la construcción de bases de datos de las empresas de los sectores seleccionados para posteriormente obtener información de la generación de residuos sólidos por medio de encuestas realizadas por un aplicativo web, personal o telefónicamente.
Mónica Alejandra Moreno Machado; Jorge Enrique Arenas Hernández; Jacipt Alexander Ramón Valencia
2015-01-01
La investigación apunta al conocimiento del impacto ambiental negativo generado por el uso de palancas en la actividad minera subterránea en el período 2006-2013 en el departamento de Norte de Santander. La fecha de otorgamiento de las licencias ambientales permitió definir con precisión los volúmenes de explotación y en consecuencia las cantidades de madera necesarias para la construcción de las estructuras de fortificación, más específicamente las palancas. A la fecha de la investigación se...
Montserrat Armele; Desirée Díaz; Jorge Galeano
2014-01-01
Entre las consecuencias generadas por las cardiopatías congénitas se encuentran los trastornos cognitivos. A continuación se exponen los resultados de la intervención neuropsicológica en la paciente (MCGD de 9 años) con trastornos del desarrollo generados por una cardiopatía compleja de origen congénito. La niña presentaba dificultades a nivel de la organización de todas las funciones cerebrales superiores (lenguaje, praxias y gnosias). En vista de los resultados en las pruebas de evaluación,...
Avilés Benítez, Antonio
2016-01-01
ANÁLISIS DE LOS IMPACTOS AMBIENTALES GENERADOS POR PARQUES EÓLICOS EN BASE AL NUEVO DECRETO-LEY 5/2014 Con el nuevo Decreto -ley 5/2014, de 22 de abril, de medidas normativas para reducir las trabas administrativas para las empresas, los parques eólicos se encuentran incluidos en el Anexo III, exigiéndoseles para su instalación tener favorable el trámite de Autorización Ambiental Unificada (AAU). Dicha autorización exige la redacción de un Estudio de Impacto Ambiental que analice y cuanti...
Aplicación del análisis de sentimientos a la evaluación de datos generados en medios sociales
López Barbosa, Rutilio Rodolfo
2015-01-01
El presente documento describe el proceso de investigación y desarrollo llevado a cabo en la disciplina del análisis de sentimientos. El objetivo principal de esta investigación fue evaluar la aplicación de las tecnologías del análisis de sentimientos al contenido generado por los usuarios de distintos medios sociales y presentar propuestas de aprovechamiento de los resultados de estas tecnologías a las organizaciones y usuarios. Se estudió el grado de confiabilidad de las herramientas en lín...
Pérez, C.; Toso, M. T; Rulli, Florencia
2007-01-01
Las funciones universitarias incluyen docencia, investigación y extensión. Integrando ellas, decidimos difundir conocimientos científicos impartidos y generados por la UBA a alumnos de 4º grado de una escuela primaria porteña. De esta forma, surgió esta experiencia innovadora perteneciente a la serie "De la Universidad a la Escuela". Objetivos: Estimular el interés de los niños por el cuidado de la salud, la Medicina y disciplinas afines. Propiciar la apertura a la investigación científica. C...
CHY formula and MHV amplitudes
Du, Yi-Jian; Teng, Fei; Wu, Yong-Shi
2016-05-01
In this paper, we study the relation between the Cachazo-He-Yuan (CHY) formula and the maximal-helicity-violating (MHV) amplitudes of Yang-Mills and gravity in four dimensions. We prove that only one special rational solution of the scattering equations found by Weinzierl supports the MHV amplitudes. Namely, localized at this solution, the integrated CHY formula produces the Parke-Taylor formula for MHV Yang-Mills amplitudes as well as the Hodges formula for MHV gravitational amplitudes, with an arbitrary number of external gluons/gravitons. This is achieved by developing techniques, in a manifestly Möbius covariant formalism, to explicitly compute relevant reduced Pfaffians/determinants. We observe and prove two interesting properties (or identities), which facilitate the computations. We also check that all the other ( n - 3)! - 1 solutions to the scattering equations do not support the MHV amplitudes, and prove analytically that this is indeed true for the other special rational solution proposed by Weinzierl, that actually supports the anti-MHV amplitudes. Our results reveal a mysterious feature of the CHY formalism that in Yang-Mills and gravity theory, solutions of scattering equations, involving only external momenta, somehow know about the configuration of external polarizations of the scattering amplitudes.
Teleporting Superpositions of Chiral Amplitudes
Maierle, C S; Harris, R A; Maierle, Christopher S.; Lidar, Daniel A.; Harris, Robert A.
1998-01-01
Chiral molecules may exist in superpositions of left- and right-handed states. We show how the amplitudes of such superpositions may be teleported to the polarization degrees of freedom of a photon. Two experimental schemes are proposed, one leading to perfect, the other to state-dependent teleportation. Both methods yield complete information about the amplitudes. This is the first explicit example of "inter-species" teleportation, where the amplitudes of the quantum superposition of one species are transferred at the end of the process to a different species. The latter is then easily accessible for measurement.
Positive Amplitudes In The Amplituhedron
Arkani-Hamed, Nima; Trnka, Jaroslav
2014-01-01
The all-loop integrand for scattering amplitudes in planar N = 4 SYM is determined by an "amplitude form" with logarithmic singularities on the boundary of the amplituhedron. In this note we provide strong evidence for a new striking property of the superamplitude, which we conjecture to be true to all loop orders: the amplitude form is positive when evaluated inside the amplituhedron. The statement is sensibly formulated thanks to the natural "bosonization" of the superamplitude associated with the amplituhedron geometry. However this positivity is not manifest in any of the current approaches to scattering amplitudes, and in particular not in the cellulations of the amplituhedron related to on-shell diagrams and the positive grassmannian. The surprising positivity of the form suggests the existence of a "dual amplituhedron" formulation where this feature would be made obvious. We also suggest that the positivity is associated with an extended picture of amplituhedron geometry, with the amplituhedron sitting...
Scattering amplitudes in gauge theories
Henn, Johannes M
2014-01-01
At the fundamental level, the interactions of elementary particles are described by quantum gauge field theory. The quantitative implications of these interactions are captured by scattering amplitudes, traditionally computed using Feynman diagrams. In the past decade tremendous progress has been made in our understanding of and computational abilities with regard to scattering amplitudes in gauge theories, going beyond the traditional textbook approach. These advances build upon on-shell methods that focus on the analytic structure of the amplitudes, as well as on their recently discovered hidden symmetries. In fact, when expressed in suitable variables the amplitudes are much simpler than anticipated and hidden patterns emerge. These modern methods are of increasing importance in phenomenological applications arising from the need for high-precision predictions for the experiments carried out at the Large Hadron Collider, as well as in foundational mathematical physics studies on the S-matrix in quantum ...
Model selection for amplitude analysis
International Nuclear Information System (INIS)
Model complexity in amplitude analyses is often a priori under-constrained since the underlying theory permits a large number of possible amplitudes to contribute to most physical processes. The use of an overly complex model results in reduced predictive power and worse resolution on unknown parameters of interest. Therefore, it is common to reduce the complexity by removing from consideration some subset of the allowed amplitudes. This paper studies a method for limiting model complexity from the data sample itself through regularization during regression in the context of a multivariate (Dalitz-plot) analysis. The regularization technique applied greatly improves the performance. An outline of how to obtain the significance of a resonance in a multivariate amplitude analysis is also provided
Analytization of elastic scattering amplitude
Troshin, S M
2016-01-01
Dependence of the real part of the elastic scattering amplitude on the transferred momentum -t at the asymptotical energies has been restored from the corresponding imaginary part on the basis of derivative analyticity relations (analytization).
One loop multiphoton helicity amplitudes
Mahlon, G
1994-01-01
We use the solutions to the recursion relations for double-off-shell fermion currents to compute helicity amplitudes for $n$-photon scattering and electron-positron annihilation to photons in the massless limit of QED. The form of these solutions is simple enough to allow {\\it all}\\ of the integrations to be performed explicitly. For $n$-photon scattering, we find that unless $n=4$, the amplitudes for the helicity configurations (+++...+) and (-++...+) vanish to one-loop order.
Motivic amplitudes and cluster coordinates
International Nuclear Information System (INIS)
In this paper we study motivic amplitudes — objects which contain all of the essential mathematical content of scattering amplitudes in planar SYM theory in a completely canonical way, free from the ambiguities inherent in any attempt to choose particular functional representatives. We find that the cluster structure on the kinematic configuration space Confn(ℙ3) underlies the structure of motivic amplitudes. Specifically, we compute explicitly the coproduct of the two-loop seven-particle MHV motivic amplitude A7,2M and find that like the previously known six-particle amplitude, it depends only on certain preferred coordinates known in the mathematics literature as cluster X-coordinates on Confn(ℙ3). We also find intriguing relations between motivic amplitudes and the geometry of generalized associahedrons, to which cluster coordinates have a natural combinatoric connection. For example, the obstruction to A7,2M being expressible in terms of classical polylogarithms is most naturally represented by certain quadrilateral faces of the appropriate associahedron. We also find and prove the first known functional equation for the trilogarithm in which all 40 arguments are cluster X-coordinates of a single algebra. In this respect it is similar to Abel’s 5-term dilogarithm identity
Simulation of absolute amplitudes of ultrasound signals using equivalent circuits.
Johansson, Jonny; Martinsson, Pär-Erik; Delsing, Jerker
2007-10-01
Equivalent circuits for piezoelectric devices and ultrasonic transmission media can be used to cosimulate electronics and ultrasound parts in simulators originally intended for electronics. To achieve efficient system-level optimization, it is important to simulate correct, absolute amplitude of the ultrasound signal in the system, as this determines the requirements on the electronics regarding dynamic range, circuit noise, and power consumption. This paper presents methods to achieve correct, absolute amplitude of an ultrasound signal in a simulation of a pulse-echo system using equivalent circuits. This is achieved by taking into consideration loss due to diffraction and the effect of the cable that connects the electronics and the piezoelectric transducer. The conductive loss in the transmission line that models the propagation media of the ultrasound pulse is used to model the loss due to diffraction. Results show that the simulated amplitude of the echo follows measured values well in both near and far fields, with an offset of about 10%. The use of a coaxial cable introduces inductance and capacitance that affect the amplitude of a received echo. Amplitude variations of 60% were observed when the cable length was varied between 0.07 m and 2.3 m, with simulations predicting similar variations. The high precision in the achieved results show that electronic design and system optimization can rely on system simulations alone. This will simplify the development of integrated electronics aimed at ultrasound systems. PMID:18019234
Caracterización composicional de los depósitos arenosos actuales generados en el Sistema Central
Directory of Open Access Journals (Sweden)
Arribas, J.
1989-08-01
Full Text Available In this work we have studied the light mineral fraction of modern sands derived from single source lithologies (plutonic, gneissic or slate-schists in the Sistema Central (Central Spain. In this way we can analize the control of the source area lithology in sand composition. First we pay attention on tbe control of grain size sand in composition. Rock fragments decrease when grain size decreases. However, the amount of feldspar increases due to its low mechanical stability. Thus, the K/P index (K-feldspar/plagioclases is highly variable with grain size, because the different mechanical stabilities of both minerals. The trends of the amounts of components in relation with grain size are very similar, in a11 deposits. However, each percentages vary markedly between source areas with different lithologies. The projection area of the studied sands in a QFFR díagram is highly controled by grain size and lithology of source area. Thus, sands derived from slate-schists lithology appear near QFR fringe in a11 grain size fractions. Sands derived from plutonic or gneissic rocks have a high dispersion in the diagram, fram FR pole to QF fringe, depending on grain size of the sand. We conclude that the use of a single sand size fraction (0,5-0,25 mm to provenance analysis permits to discrimine source lithologies, but with a 1055 of information about global deposit compositionSe caracteriza composicionalmente la fracción ligera arenosa de los depósitos detríticos actuales generados en zonas de cabecera de arroyos que drenan macizos del Sistema Central con distintas litologías (plutónicas, gnéisicas o pizarras-esquistos. Dicha caracterización se ha basado en el análisis petrográfico de las muestras recogidas. Este análisis se ha efectuado, en cada muestra, en cinco fracciones de tamaño con intervalos de l Ì£Ç¾ entre 2 mm y 0,062 mm. De este modo se estudia el control que ejercen tanto la litología del área fuente como el tamaño de grano en
Nonsinglet pentagons and NMHV amplitudes
Energy Technology Data Exchange (ETDEWEB)
Belitsky, A.V., E-mail: andrei.belitsky@asu.edu
2015-07-15
Scattering amplitudes in maximally supersymmetric gauge theory receive a dual description in terms of the expectation value of the super Wilson loop stretched on a null polygonal contour. This makes the analysis amenable to nonperturbative techniques. Presently, we elaborate on a refined form of the operator product expansion in terms of pentagon transitions to compute twist-two contributions to NMHV amplitudes. To start with, we provide a novel derivation of scattering matrices starting from Baxter equations for flux-tube excitations propagating on magnon background. We propose bootstrap equations obeyed by pentagon form factors with nonsinglet quantum numbers with respect to the R-symmetry group and provide solutions to them to all orders in 't Hooft coupling. These are then successfully confronted against available perturbative calculations for NMHV amplitudes to four-loop order.
Nonsinglet pentagons and NMHV amplitudes
Directory of Open Access Journals (Sweden)
A.V. Belitsky
2015-07-01
Full Text Available Scattering amplitudes in maximally supersymmetric gauge theory receive a dual description in terms of the expectation value of the super Wilson loop stretched on a null polygonal contour. This makes the analysis amenable to nonperturbative techniques. Presently, we elaborate on a refined form of the operator product expansion in terms of pentagon transitions to compute twist-two contributions to NMHV amplitudes. To start with, we provide a novel derivation of scattering matrices starting from Baxter equations for flux-tube excitations propagating on magnon background. We propose bootstrap equations obeyed by pentagon form factors with nonsinglet quantum numbers with respect to the R-symmetry group and provide solutions to them to all orders in 't Hooft coupling. These are then successfully confronted against available perturbative calculations for NMHV amplitudes to four-loop order.
Factorization of Chiral String Amplitudes
Huang, Yu-tin; Yuan, Ellis Ye
2016-01-01
We re-examine a closed-string model defined by altering the boundary conditions for one handedness of two-dimensional propagators in otherwise-standard string theory. We evaluate the amplitudes using Kawai-Lewellen-Tye factorization into open-string amplitudes. The only modification to standard string theory is effectively that the spacetime Minkowski metric changes overall sign in one open-string factor. This cancels all but a finite number of states: As found in earlier approaches, with enough supersymmetry (e.g., type II) the tree amplitudes reproduce those of the massless truncation of ordinary string theory. However, we now find for the other cases that additional fields, formerly thought to be auxiliary, describe new spin-2 states at the two adjacent mass levels (tachyonic and tardyonic). The tachyon is always a ghost, but can be avoided in the heterotic case.
OPE for all Helicity Amplitudes
Basso, Benjamin; Cordova, Lucia; Sever, Amit; Vieira, Pedro
2014-01-01
We extend the Operator Product Expansion (OPE) for scattering amplitudes in planar N=4 SYM to account for all possible helicities of the external states. This is done by constructing a simple map between helicity configurations and so-called charged pentagon transitions. These OPE building blocks are generalizations of the bosonic pentagons entering MHV amplitudes and they can be bootstrapped at finite coupling from the integrable dynamics of the color flux tube. A byproduct of our map is a simple realization of parity in the super Wilson loop picture.
Catalizador para la mejora de aceites sintéticos generados a partir de material polímero de desecho.
Mastral Lamarca, Ana María; Murillo Villuendas, Ramón
2005-01-01
Catalizador para la mejora de aceites sintéticos generados a partir de material polímero de desecho. Un catalizador para la mejora de aceites sintéticos de procesado de materiales poliméricos de desecho, especialmente neumáticos de desecho, que contiene Mo como especie metálica principal soportado sobre un material poroso, preferentemente el negro de carbón residual de la obtención de los aceites sintéticos a partir de neumático, y de un tamaño preferido de partícula de 0,05-0,015 mm. El prec...
Employing helicity amplitudes for resummation
Moult, Ian; Stewart, Iain W.; Tackmann, Frank J.; Waalewijn, Wouter J.
2016-05-01
Many state-of-the-art QCD calculations for multileg processes use helicity amplitudes as their fundamental ingredients. We construct a simple and easy-to-use helicity operator basis in soft-collinear effective theory (SCET), for which the hard Wilson coefficients from matching QCD onto SCET are directly given in terms of color-ordered helicity amplitudes. Using this basis allows one to seamlessly combine fixed-order helicity amplitudes at any order they are known with a resummation of higher-order logarithmic corrections. In particular, the virtual loop amplitudes can be employed in factorization theorems to make predictions for exclusive jet cross sections without the use of numerical subtraction schemes to handle real-virtual infrared cancellations. We also discuss matching onto SCET in renormalization schemes with helicities in 4- and d -dimensions. To demonstrate that our helicity operator basis is easy to use, we provide an explicit construction of the operator basis, as well as results for the hard matching coefficients, for p p →H +0 , 1, 2 jets, p p →W /Z /γ +0 , 1, 2 jets, and p p →2 , 3 jets. These operator bases are completely crossing symmetric, so the results can easily be applied to processes with e+e- and e-p collisions.
Positivity of spin foam amplitudes
International Nuclear Information System (INIS)
The amplitude for a spin foam in the Barrett-Crane model of Riemannian quantum gravity is given as a product over its vertices, edges and faces, with one factor of the Riemannian 10j symbols appearing for each vertex, and simpler factors for the edges and faces. We prove that these amplitudes are always nonnegative for closed spin foams. As a corollary, all open spin foams going between a fixed pair of spin networks have real amplitudes of the same sign. This means one can use the Metropolis algorithm to compute expectation values of observables in the Riemannian Barrett-Crane model, as in statistical mechanics, even though this theory is based on a real-time (eiS) rather than imaginary-time e-S path integral. Our proof uses the fact that when the Riemannian 10j symbols are nonzero, their sign is positive or negative depending on whether the sum of the ten spins is an integer or half-integer. For the product of 10j symbols appearing in the amplitude for a closed spin foam, these signs cancel. We conclude with some numerical evidence suggesting that the Lorentzian 10j symbols are always nonnegative, which would imply similar results for the Lorentzian Barrett-Crane model
Discontinuity formulas for multiparticle amplitudes
International Nuclear Information System (INIS)
It is shown how discontinuity formulas for multiparticle scattering amplitudes are derived from unitarity and analyticity. The assumed analyticity property is the normal analytic structure, which was shown to be equivalent to the space-time macrocausality condition. The discontinuity formulas to be derived are the basis of multi-particle fixed-t dispersion relations
Scattering amplitudes in gauge theories
International Nuclear Information System (INIS)
First monographical text on this fundamental topic. Course-tested, pedagogical and self-contained exposition. Includes exercises and solutions. At the fundamental level, the interactions of elementary particles are described by quantum gauge field theory. The quantitative implications of these interactions are captured by scattering amplitudes, traditionally computed using Feynman diagrams. In the past decade tremendous progress has been made in our understanding of and computational abilities with regard to scattering amplitudes in gauge theories, going beyond the traditional textbook approach. These advances build upon on-shell methods that focus on the analytic structure of the amplitudes, as well as on their recently discovered hidden symmetries. In fact, when expressed in suitable variables the amplitudes are much simpler than anticipated and hidden patterns emerge. These modern methods are of increasing importance in phenomenological applications arising from the need for high-precision predictions for the experiments carried out at the Large Hadron Collider, as well as in foundational mathematical physics studies on the S-matrix in quantum field theory. Bridging the gap between introductory courses on quantum field theory and state-of-the-art research, these concise yet self-contained and course-tested lecture notes are well-suited for a one-semester graduate level course or as a self-study guide for anyone interested in fundamental aspects of quantum field theory and its applications. The numerous exercises and solutions included will help readers to embrace and apply the material presented in the main text.
Employing Helicity Amplitudes for Resummation
Moult, Ian; Tackmann, Frank J; Waalewijn, Wouter J
2015-01-01
Many state-of-the-art QCD calculations for multileg processes use helicity amplitudes as their fundamental ingredients. We construct a simple and easy-to-use helicity operator basis in soft-collinear effective theory (SCET), for which the hard Wilson coefficients from matching QCD onto SCET are directly given in terms of color-ordered helicity amplitudes. Using this basis allows one to seamlessly combine fixed-order helicity amplitudes at any order they are known with a resummation of higher-order logarithmic corrections. In particular, the virtual loop amplitudes can be employed in factorization theorems to make predictions for exclusive jet cross sections without the use of numerical subtraction schemes to handle real-virtual infrared cancellations. We also discuss matching onto SCET in renormalization schemes with helicities in $4$- and $d$-dimensions. To demonstrate that our helicity operator basis is easy to use, we provide an explicit construction of the operator basis, as well as results for the hard m...
Employing helicity amplitudes for resummation
International Nuclear Information System (INIS)
Many state-of-the-art QCD calculations for multileg processes use helicity amplitudes as their fundamental ingredients. We construct a simple and easy-to-use helicity operator basis in soft-collinear effective theory (SCET), for which the hard Wilson coefficients from matching QCD onto SCET are directly given in terms of color-ordered helicity amplitudes. Using this basis allows one to seamlessly combine fixed-order helicity amplitudes at any order they are known with a resummation of higher-order logarithmic corrections. In particular, the virtual loop amplitudes can be employed in factorization theorems to make predictions for exclusive jet cross sections without the use of numerical subtraction schemes to handle real-virtual infrared cancellations. We also discuss matching onto SCET in renormalization schemes with helicities in 4- and d-dimensions. To demonstrate that our helicity operator basis is easy to use, we provide an explicit construction of the operator basis, as well as results for the hard matching coefficients, for pp → H+0,1,2 jets, pp → W/Z/γ+0,1,2 jets, and pp → 2,3 jets. These operator bases are completely crossing symmetric, so the results can easily be applied to processes with e+e- and e-p collisions.
International Nuclear Information System (INIS)
Work on the derivation of an explicit perturbation series for string and superstring amplitudes is reviewed. The light-cone approach is emphasized, but some work on the Polyakov approach is also mentioned, and the two methods are compared. The calculation of the measure factor is outlined in the interacting-string picture
Energy Technology Data Exchange (ETDEWEB)
Mandelstam, S.
1986-06-01
Work on the derivation of an explicit perturbation series for string and superstring amplitudes is reviewed. The light-cone approach is emphasized, but some work on the Polyakov approach is also mentioned, and the two methods are compared. The calculation of the measure factor is outlined in the interacting-string picture. (LEW)
Veneziano Amplitude for Winding Strings
Khuri, Ramzi R.
1993-01-01
String configurations with nonzero winding number describe soliton string states. We compute the Veneziano amplitude for the scattering of arbitrary winding states and show that in the large radius limit the strings always scatter trivially and with no change in the individual winding numbers of the strings. In this limit, then, these states scatter as true solitons.
Discontinuity formulas for multiparticle amplitudes
Energy Technology Data Exchange (ETDEWEB)
Stapp, H.P.
1976-03-01
It is shown how discontinuity formulas for multiparticle scattering amplitudes are derived from unitarity and analyticity. The assumed analyticity property is the normal analytic structure, which was shown to be equivalent to the space-time macrocausality condition. The discontinuity formulas to be derived are the basis of multi-particle fixed-t dispersion relations.
Media Pedagogy: Media Education, Media Socialisation and Educational Media
Lars Qvortrup
2007-01-01
The aim of this paper is to examine the relationship between education and media. These two concepts can be combined in three ways: one can think of media education, i.e. education in the subject of mass media. One can think of media socialisation, i.e. education within the context of a media society in which pupils and students are experienced media users. Finally, one can think of educational media, i.e. media used for educational purposes.After having specified these three subject areas, t...
Gauge and Gravity Amplitude Relations
Carrasco, John Joseph M
2015-01-01
In these lectures I talk about simplifications and universalities found in scattering amplitudes for gauge and gravity theories. In contrast to Ward identities, which are understood to arise from familiar symmetries of the classical action, these structures are currently only understood in terms of graphical organizational principles, such as the gauge-theoretic color-kinematics duality and the gravitational double-copy structure, for local representations of multi-loop S-matrix elements. These graphical principles make manifest new relationships in and between gauge and gravity scattering amplitudes. My lectures will focus on arriving at such graphical organizations for generic theories with examples presented from maximal supersymmetry, and their use in unitarity-based multi-loop integrand construction.
Scruncher phase and amplitude control
International Nuclear Information System (INIS)
The analog controller for phase and amplitude control of a 402.5 MHz super conducting cavity is described in this paper. The cavity is a single cell with niobium explosively bonded to a copper cavity. It is used as an energy compressor for pions at the Clinton P. Anderson Meson Physics Facility (LAMPF). The controller maintains cavity frequency to within 4 degrees in phase of the LAMPF beam frequency. Field amplitude is maintained to within 2 percent. This control is accomplished at critical coupling (Q load of 1 x 109) with the use of only a 30 watt rf amplifier for accelerating fields of 6 MV/m. The design includes the use of piezoelectric crystals for fast resonance control. Three types of control, self excited, VCO, and a reference frequency driven, were tried on this cavity and we present a comparison of their performance. (Author) 4 figs., ref
Pulse amplitude modulated chlorophyll fluorometer
Energy Technology Data Exchange (ETDEWEB)
Greenbaum, Elias; Wu, Jie
2015-12-29
Chlorophyll fluorometry may be used for detecting toxins in a sample because of changes in micro algae. A portable lab on a chip ("LOAC") based chlorophyll fluorometer may be used for toxin detection and environmental monitoring. In particular, the system may include a microfluidic pulse amplitude modulated ("PAM") chlorophyll fluorometer. The LOAC PAM chlorophyll fluorometer may analyze microalgae and cyanobacteria that grow naturally in source drinking water.
Fuller, Matthew; Goffey, Andrew (translated by)
2012-01-01
Evil Media develops a philosophy of media power that extends the concept of media beyond its tried and trusted use in the games of meaning, symbolism, and truth. It addresses the gray zones in which media exist as corporate work systems, algorithms and data structures, twenty-first century self-improvement manuals, and pharmaceutical techniques. Evil Media invites the reader to explore and understand the abstract infrastructure of the present day. From search engines to flirting strategies, f...
Strasburger, Victor C
2010-11-01
The American Academy of Pediatrics recognizes that exposure to mass media (eg, television, movies, video and computer games, the Internet, music lyrics and videos, newspapers, magazines, books, advertising) presents health risks for children and adolescents but can provide benefits as well. Media education has the potential to reduce the harmful effects of media and accentuate the positive effects. By understanding and supporting media education, pediatricians can play an important role in reducing harmful effects of media on children and adolescents. PMID:20876180
Effective anisotropy through traveltime and amplitude matching
Wang, Hui
2014-08-05
Introducing anisotropy to seismic wave propagation reveals more realistic physics of our Earth\\'s subsurface as compared to the isotropic assumption. However wavefield modeling, the engine of seismic inverse problems, in anisotropic media still suffers from computational burdens, in particular with complex anisotropy such as transversely isotropic (TI) and Orthorhombic anisotropy. We develop effective isotropic velocity and density models to package the effects of anisotropy such that the wave propagation behavior using these effective models approximate those of the original anisotropic model. We build these effective models through the high frequency asymptotic approximation based on the eikonal and transport equations. We match the geometrical behavior of the wave-fields, given by traveltimes, from the anisotropic and isotropic eikonal equations. This matching yields the effective isotropic velocity that approximates the kinematics of the anisotropic wavefield. Equivalently, we calculate the effective densities by equating the anisotropic and isotropic transport equations. The effective velocities and densities are then fed into the isotropic acoustic variable density wave equation to obtain cheaper anisotropic wavefields. We justify our approach by testing it on an elliptical anisotropic model. The numerical results demonstrate a good matching of both traveltime and amplitude between anisotropic and effective isotropic wavefields.
Gelu Mihai LEICU; Laura Rita PITARIU
2015-01-01
Media are part of our lives today. Our pupils watch TV, play online games, blog, upload videos on YouTube, use Facebook, etc. Messages transmitted by the media flow constantly into our and their minds. Media literacy provides us with a range of information and abilities which help us analyse, evaluate, and even create messages in various modes of the media. Students are encouraged to think critically about the media they consume. Hobbs has found out that media literacy implies: a set of skill...
Directory of Open Access Journals (Sweden)
Montserrat Armele
2014-06-01
Full Text Available Entre las consecuencias generadas por las cardiopatías congénitas se encuentran los trastornos cognitivos. A continuación se exponen los resultados de la intervención neuropsicológica en la paciente (MCGD de 9 años con trastornos del desarrollo generados por una cardiopatía compleja de origen congénito. La niña presentaba dificultades a nivel de la organización de todas las funciones cerebrales superiores (lenguaje, praxias y gnosias. En vista de los resultados en las pruebas de evaluación, se diseñaron estrategias de intervención neuropsicológica integral y personalizada. Esto permitió en 5 años llevar a la paciente de un estado de escasa funcionalidad social, emocional, física y cognitiva, a otro de multifuncionalidad adecuada en todos los ámbitos.
Grassmannian geometry of scattering amplitudes
Arkani-Hamed, Nima; Cachazo, Freddy; Goncharov, Alexander; Postnikov, Alexander; Trnka, Jaroslav
2016-01-01
Outlining a revolutionary reformulation of the foundations of perturbative quantum field theory, this book is a self-contained and authoritative analysis of the application of this new formulation to the case of planar, maximally supersymmetric Yang–Mills theory. The book begins by deriving connections between scattering amplitudes and Grassmannian geometry from first principles before introducing novel physical and mathematical ideas in a systematic manner accessible to both physicists and mathematicians. The principle players in this process are on-shell functions which are closely related to certain sub-strata of Grassmannian manifolds called positroids - in terms of which the classification of on-shell functions and their relations becomes combinatorially manifest. This is an essential introduction to the geometry and combinatorics of the positroid stratification of the Grassmannian and an ideal text for advanced students and researchers working in the areas of field theory, high energy physics, and the...
New identities among gauge theory amplitudes
Bjerrum-Bohr, N. E. J.; Damgaard, Poul H.; Feng, Bo; Søndergaard, Thomas
2010-08-01
Color-ordered amplitudes in gauge theories satisfy non-linear identities involving amplitude products of different helicity configurations. We consider the origin of such identities and connect them to the Kawai-Lewellen-Tye (KLT) relations between gravity and gauge theory amplitudes. Extensions are made to one-loop order of the full N = 4 super Yang-Mills multiplet.
New identities among gauge theory amplitudes
Energy Technology Data Exchange (ETDEWEB)
Bjerrum-Bohr, N.E.J., E-mail: bjbohr@nbi.d [Niels Bohr International Academy and Discovery Center, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen (Denmark); Damgaard, Poul H. [Niels Bohr International Academy and Discovery Center, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen (Denmark); Feng Bo [Center of Mathematical Science, Zhejiang University, Hangzhou (China); Kavli Institute for Theoretical Physics China, CAS, Beijing 100190 (China); Sondergaard, Thomas [Niels Bohr International Academy and Discovery Center, Niels Bohr Institute, Blegdamsvej 17, DK-2100 Copenhagen (Denmark)
2010-08-09
Color-ordered amplitudes in gauge theories satisfy non-linear identities involving amplitude products of different helicity configurations. We consider the origin of such identities and connect them to the Kawai-Lewellen-Tye (KLT) relations between gravity and gauge theory amplitudes. Extensions are made to one-loop order of the full N=4 super Yang-Mills multiplet.
New Identities among Gauge Theory Amplitudes
Bjerrum-Bohr, N E J; Feng, Bo; Sondergaard, Thomas
2010-01-01
Color-ordered amplitudes in gauge theories satisfy non-linear identities involving amplitude products of different helicity configurations. We consider the origin of such identities and connect them to the Kawai-Lewellen-Tye (KLT) relations between gravity and gauge theory amplitudes. Extensions are made to one-loop order of the full N=4 super Yang-Mills multiplet.
New identities among gauge theory amplitudes
International Nuclear Information System (INIS)
Color-ordered amplitudes in gauge theories satisfy non-linear identities involving amplitude products of different helicity configurations. We consider the origin of such identities and connect them to the Kawai-Lewellen-Tye (KLT) relations between gravity and gauge theory amplitudes. Extensions are made to one-loop order of the full N=4 super Yang-Mills multiplet.
Quantum Amplitude Amplification and Estimation
Brassard, G; Mosca, M; Tapp, A; Brassard, Gilles; Hoyer, Peter; Mosca, Michele; Tapp, Alain
2000-01-01
Consider a Boolean function $\\chi: X \\to \\{0,1\\}$ that partitions set $X$ between its good and bad elements, where $x$ is good if $\\chi(x)=1$ and bad otherwise. Consider also a quantum algorithm $\\mathcal A$ such that $A \\ket{0} = \\sum_{x\\in X} \\alpha_x \\ket{x}$ is a quantum superposition of the elements of $X$, and let $a$ denote the probability that a good element is produced if $A \\ket{0}$ is measured. If we repeat the process of running $A$, measuring the output, and using $\\chi$ to check the validity of the result, we shall expect to repeat $1/a$ times on the average before a solution is found. *Amplitude amplification* is a process that allows to find a good $x$ after an expected number of applications of $A$ and its inverse which is proportional to $1/\\sqrt{a}$, assuming algorithm $A$ makes no measurements. This is a generalization of Grover's searching algorithm in which $A$ was restricted to producing an equal superposition of all members of $X$ and we had a promise that a single $x$ existed such tha...
Directory of Open Access Journals (Sweden)
Alexander Álvarez Contreras
2006-01-01
Full Text Available En este trabajo se realizó un diagnóstico de calidad y cantidad del lixiviado generado en el relleno sanitario El Guayabal de la ciudad San José de Cúcuta, y se evaluaron dos sistemas de tratamiento biológico a escala laboratorio para este lixiviado. El lixiviado en el momento de la experiencia presentaba un rango de DQO de 7.650 a 28.250 mg/L. Los sistemas de tratamiento ensayados fueron: un reactor anaerobio del tipo UASB y un sistema de Biodiscos. La carga máxima asimilada por el sistema de Biodiscos fue de 31 gDQO/m2*d, con una eficiencia de remoción promedio en DQO de 70% y eficiencias de remoción máximas por encima del 90% para una carga óptima en un rango de 15 a 20 gDQO/m2*d; además, este sistema presentó gran estabilidad frente a variaciones importantes en cuanto a las características del lixiviado y ausencia de olores desagradables. Los porcentajes de remoción de DQO en el reactor UASB eran muy variables, con picos bajos y caídas muy marcadas, que indican que no se presentaba un funcionamiento óptimo del proceso durante la mayor parte del período de operación del reactor UASB; esto se debió principalmente a que no se tuvieron en cuenta las estrictas condiciones de este sistema.
DEFF Research Database (Denmark)
Kabel, Lars
2015-01-01
News and other kinds of journalistic stories, 16-17 hours a day, all year round, on all platforms, also the moderated social media. The key research thesis behind this article is that the continuous and speedy stream of news stories and media content now is becoming the centre of the production...... processes and the value creation in converged multimedia newsrooms. The article identify new methods and discuss editorial challenges in handling media flow....
O' Neill, Brian; Hagen, Ingun
2009-01-01
Across Europe and beyond, the promotion of media literacy, for children and adults, has acquired an important public urgency. Traditional literacy is seen to be no longer sufficient for participation in today’s society. Citizens need to be media literate, it is claimed, to enable them to cope more effectively with the flood of information in today’s highly mediated societies. As teachers, politicians and policy makers everywhere struggle with this rapid shift in media culture, greater respons...
Institute of Scientific and Technical Information of China (English)
叶全荣
2006-01-01
@@ Every day,we are all influenced by the mass media.Although some critics of the media claim that these means of communication are used mainly to control our thinking and get us to buy products that we don't need,the media also contribute to keeping people informed.In other words,while dangers do exist,the benefits of the media far outweigh(超过)the disadvantages.Most of the messages brought to viewers,listeners,and readers are designed either to inform or to entertain,and neither of these goals can be considered dangerous or harmful.
Gravity and Yang-Mills amplitude relations
International Nuclear Information System (INIS)
Using only general features of the S matrix and quantum field theory, we prove by induction the Kawai-Lewellen-Tye relations that link products of gauge theory amplitudes to gravity amplitudes at tree level. As a bonus of our analysis, we provide a novel and more symmetric form of these relations. We also establish an infinite tower of new identities between amplitudes in gauge theories.
On the singularities of massive superstring amplitudes
Energy Technology Data Exchange (ETDEWEB)
Foda, O.
1987-06-04
Superstring one-loop amplitudes with massive external states are shown to be in general ill-defined due to internal on-shell propagators. However, we argue that since any massive string state (in the uncompactified theory) has a finite lifetime to decay into massless particles, such amplitudes are not terms in the perturbative expansion of physical S-matrix elements: These can be defined only with massless external states. Consistent massive amplitudes repuire an off-shell formalism.
On the singularities of massive superstring amplitudes
International Nuclear Information System (INIS)
Superstring one-loop amplitudes with massive external states are shown to be in general ill-defined due to internal on-shell propagators. However, we argue that since any massive string state (in the uncompactified theory) has a finite lifetime to decay into massless particles, such amplitudes are not terms in the perturbative expansion of physical S-matrix elements: These can be defined only with massless external states. Consistent massive amplitudes repuire an off-shell formalism. (orig.)
On the singularities of massive superstring amplitudes
Foda, O.
1987-01-01
Superstring one-loop amplitudes with massive external states are shown to be in general ill-defined due to internal on-shell propagators. However, we argue that since any massive string state (in the uncompactified theory) has a finite lifetime to decay into massless particles, such amplitudes are not terms in the perturbative expansion of physical S-matrix elements: these can be defined only with massless external states. Consistent massive amplitudes require an off-shell formalism.
The Trace Formula of the Spinoriel Amplitude
Mekhfi, M.
2009-01-01
We re express the fermion's probability amplitude as a trace over spinor indices, which formulation surprisingly does not exist in literature. This formulation puts the probabilty amplitude and the the probabilty(squared amplitude) of a given process on equal footing at the compuational level and this is our principal motivation to write the present paper. We test the power of the trace formula in three applications: Calculation of the charge-current of fermions by using symbolic programs, wh...
Covariant method for calculating helicity amplitudes
International Nuclear Information System (INIS)
We present an alternative approach for calculating helicity amplitudes for processes involving both massless and massive fermions. With this method one can easily obtain covariant expressions for the helicity amplitudes. The final expressions involve only four-vector products and are independent of the basis for γ matrices or specific form of the spinors. We use the method to obtain the helicity amplitudes for several processes involving top quark production. copyright 1996 The American Physical Society
Koganuramath, M. M.; Angadi, Mallikarjun
1999-01-01
The Information Technology has revolutionised the communication media with the emergence of Internet. This paper describes the pace of change in print media to On-line journalism. The process has began with On-line journalism utilising Internet wherein websites are replacing the print media. Most of the On-line newspapers are free, interactive and archival in nature and it provides users to search the information on newspapers through various access points i.e. by contributors, title, and dat...
Peterson, Erin
2010-01-01
While institutions do not often have a hook as compelling as an eagerly awaited movie, great content is critical for media relations success--and coupling it with the right distribution channel can ensure the story finds the right audience. Even better, retooling it for several media platforms can extend the life and reach of a story. The changes…
Chalmers, Matthew
2008-01-01
He is the media-friendly face of particle physics, appearing on countless TV and radio shows in the run-up to the opening of CERN's Large Hadron Collider. Matthew Chalmers discovers how Brian Cox finds the time to be both a physicist and a media personality. (2 pages)
Directory of Open Access Journals (Sweden)
Mónica Alejandra Moreno Machado
2015-12-01
Full Text Available La investigación apunta al conocimiento del impacto ambiental negativo generado por el uso de palancas en la actividad minera subterránea en el período 2006-2013 en el departamento de Norte de Santander. La fecha de otorgamiento de las licencias ambientales permitió definir con precisión los volúmenes de explotación y en consecuencia las cantidades de madera necesarias para la construcción de las estructuras de fortificación, más específicamente las palancas. A la fecha de la investigación se encuentran activas ciento treinta y siete (137 licencias de minería de carbón cuya presencia se hace en diecisiete de los cuarenta municipios de la jurisdicción. Los municipios de Cúcuta, El Zulia y Sardinata poseen el 62 % de las concesiones. En cuanto al uso de la madera para la fortiiación de las minas, tan solo el 29.5 % es de origen legal. En la actividad utilizan setenta y seis tipos de madera de diferentes especies, sin embargo la especie de mayor uso es la pino pátula Pinus patula con el 38.6 % de preferencia. Con respecto a la pérdida de cobertura vegetal en el área de intervención, se realizó una revisión documental de todos y cada uno de los títulos mineros que en el período investigado estuvieran realizando explotación de carbón. Posteriormente se evaluó cada título minero, determinando que la deforestación en el período de estudio alcanzó 449 hectáreas equivalente al 1.55 % del área ocupada por la concesión. De igual manera se pudo establecer que desde 1990 a 2006 se deforestaron 4.824 hectáreas que corresponden al 18 % del área total de los títulos mineros explotados. La autoridad ambiental inició procesos ambientales sancionatorios al 14 % de los usuarios en el 2012 y al 10.6% de usuarios en el 2013.
Directory of Open Access Journals (Sweden)
Amanda Legorreta Ramírez
2011-01-01
Full Text Available Los residuos sólidos dentro de las Áreas Naturales Protegidas (ANP son considerados una de las principales consecuencias negativas derivadas de la actividad turística, debido a que atentan contra la belleza del paisaje, además de representar daños potenciales a las especies animales y vegetales existentes. El objetivo de este trabajo es conocer los tipos de residuos que se generan en el Parque de los Venados, para llevar a cabo esto, se realizó un trabajo de campo que permitiera identificar los tipos y cantidades de residuos, asimismo, se consultaron las Normas Oficiales Mexicanas recomendadas para este tipo de análisis, de igual manera, como parte de los objetivos del trabajo se identificaron tres fuentes generadoras de residuos dentro del Parque, en cada una de ellas se realizó el muestreo, caracterización por subproductos y determinación de peso volumétrico. Finalmente, los resultados obtenidos se compararon con los datos reportados en la literatura para las zonas rurales y urbanas del país, en especial con los de la zona urbana de Toluca, con el objetivo de encontrar semejanzas entre los patrones de composición de los residuos de estas zonas y los encontrados en el Parque de los Venados. Este trabajo representa un primer esfuerzo en la identificación y análisis de la composición de residuos, dentro de un Área Natural Protegida (ANP, generados por la actividad turística, la aplicación de la metodología marcada por las Normas Oficiales y su adecuación a este análisis específico forman parte también de los objetivos perseguidos por la investigación, que es el conocimiento de la normatividad que involucra a las ANP, el turismo y los residuos sólidos.
On the nullification of threshold amplitudes
Gonera, Joanna
2002-01-01
The nullification of threshold amplitudes is considered within the conventional framework of quantum field theory. The relevant Ward identities for the reduced theory are derived both on path-integral and diagrammatic levels. They are then used to prove the vanishing of tree-graph threshold amplitudes.
On the singularities of massive superstring amplitudes
Foda, O.
1987-01-01
Superstring one-loop amplitudes with massive external states are shown to be in general ill-defined due to internal on-shell propagators. However, we argue that since any massive string state (in the uncompactified theory) has a finite lifetime to decay into massless particles, such amplitudes are n
Production amplitude for a single scalar resonance
International Nuclear Information System (INIS)
We derive a simple expression for the production amplitude of two pseudoscalar mesons involving a single scalar resonance. This amplitude is determined by a combination of Watson's phase δ(s) and another phase ω(s), related to an unambiguous two-meson propagator. With a lagrangian model, we study the σππ system
Finite amplitude dynamic motion of viscoelastic materials.
Yen, H.-C.; Mcintire, L. V.
1972-01-01
It is shown that an integral constitutive relation containing a memory function depending on strain tensor invariants can describe the rheological behavior of finite amplitude oscillatory motion of polymer solutions both qualitatively and quantitatively. Values of the material constants are obtained by a numerical technique of simultaneously curve fitting simple shearing viscosity, first normal stress difference, and small amplitude oscillatory motion data.
Scattering Amplitudes via Algebraic Geometry Methods
DEFF Research Database (Denmark)
Søgaard, Mads
Feynman diagrams. The study of multiloop scattering amplitudes is crucial for the new era of precision phenomenology at the Large Hadron Collider (LHC) at CERN. Loop-level scattering amplitudes can be reduced to a basis of linearly independent integrals whose coefficients are extracted from generalized...
Amplitude death in steadily forced chaotic systems
Institute of Scientific and Technical Information of China (English)
Feng Guo-Lin; He Wen-Ping
2007-01-01
Steady forcing can induce the amplitude death in chaotic systems, which generally exists in coupled dynamic systems. Using the Lorenz system as a typical example, this paper investigates the dynamic behaviours of the chaotic system with steady forcing numerically, and finds that amplitude death can occur as the strength of the steady forcing goes beyond a critical constant.
Consistent Off-Shell Tree String Amplitudes
Liccardo, A; Marotta, R
1999-01-01
We give a construction of off-shell tree bosonic string amplitudes, based on the operatorial formalism of the N-string Vertex, with three external massless states both for open and closed strings by requiring their being projective invariant. In particular our prescription leads, in the low-energy limit, to the three-gluon amplitude in the usual covariant gauge.
New relations for gauge-theory amplitudes
International Nuclear Information System (INIS)
We present an identity satisfied by the kinematic factors of diagrams describing the tree amplitudes of massless gauge theories. This identity is a kinematic analog of the Jacobi identity for color factors. Using this we find new relations between color-ordered partial amplitudes. We discuss applications to multiloop calculations via the unitarity method. In particular, we illustrate the relations between different contributions to a two-loop four-point QCD amplitude. We also use this identity to reorganize gravity tree amplitudes diagram by diagram, offering new insight into the structure of the Kawai-Lewellen-Tye (KLT) relations between gauge and gravity tree amplitudes. This insight leads to similar but novel relations. We expect this to be helpful in higher-loop studies of the ultraviolet properties of gravity theories.
The Lorentzian proper vertex amplitude: Asymptotics
Engle, Jonathan; Zipfel, Antonia
2015-01-01
In previous work, the Lorentzian proper vertex amplitude for a spin-foam model of quantum gravity was derived. In the present work, the asymptotics of this amplitude are studied in the semi-classical limit. The starting point of the analysis is an expression for the amplitude as an action integral with action differing from that in the EPRL case by an extra `projector' term which scales linearly with spins only in the asymptotic limit. New tools are introduced to generalize stationary phase methods to this case. For the case of boundary data which can be glued to a non-degenerate Lorentzian 4-simplex, the asymptotic limit of the amplitude is shown to equal the single Feynman term, showing that the extra term in the asymptotics of the EPRL amplitude has been eliminated.
New Relations for Gauge-Theory Amplitudes
Bern, Z; Johansson, H
2008-01-01
We present an identity satisfied by the kinematic factors of diagrams describing the tree amplitudes of massless gauge theories. This identity is a kinematic analog of the Jacobi identity for color factors. Using this we find new relations between color-ordered partial amplitudes. We discuss applications to multi-loop calculations via the unitarity method. In particular, we illustrate the relations between different contributions to a two-loop four-point QCD amplitude. We also use this identity to reorganize gravity tree amplitudes diagram by diagram, offering new insight into the structure of the KLT relations between gauge and gravity tree amplitudes. This can be used to obtain novel relations similar to the KLT ones. We expect this to be helpful in higher-loop studies of the ultraviolet properties of gravity theories.
Relations Between Closed String Amplitudes at Higher-order Tree Level and Open String Amplitudes
Chen, Yi-Xin; Ma, Qian
2009-01-01
KLT relations almost factorize closed string amplitudes on $S_2$ by two open string tree amplitudes which correspond to the left- and the right- moving sectors. In this paper, we investigate string amplitudes on $D_2$ and $RP_2$. We find that KLT factorization relations do not hold in these two cases. The relations between closed and open string amplitudes have new forms. On $D_2$ and $RP_2$, the left- and the right- moving sectors are connected into a single sector. Then an amplitude with closed strings on $D_2$ or $RP_2$ can be given by one open string tree amplitude except for a phase factor. The relations depends on the topologies of the world-sheets. In the low energy limits of these two cases, the factorization relations for graviton amplitudes do not hold. The amplitudes for gravitons must be given by the new relations instead.
Sova, Ondřej
2012-01-01
This thesis deals with social media and is trying to characterize them with focus on their development which led to the creation of social networks. The history of the internet is very short, but its development was giant, and only few people can imagine the world without it. Social media grew in parallel to the internet, so they are its integral part from the beginning. Social media were slowly replacing press, because they gave us a new dimension in the form of immediate feedback. They also...
Sergio Rosas; César Luna; Oscar Sánchez; Esiquio Ortiz
2007-01-01
Se presenta el estudio técnico-económico para la obtención de ácido sulfúrico por medio del proceso de contacto doble. Con base en las características de los gases residuales generados por la tostación de piritas se selecciona la tecnología de limpieza del efluente y el proceso de producción de ácido sulfúrico. Para la limpieza de los gases se establece utilizar un tren de separación conformado por un separador ciclónico, un lavador Venturi, un eliminador de neblina y dos precipitadores elect...
William Alvarez Gaviria
1992-01-01
Se postula la hipótesis de que una de las funciones del saco endolinfático es hacer las veces de amortiguador de los contragolpes generados en el oído interno, como respuesta a las desaceleraciones súbitas ocasionadas en los Iíquidos laberínticos por el cambio o el frenado súbito de los movimientos. Si dicho amortiguador no reúne las condiciones suficientes para tal efecto como, por ejemplo, capacidad volumétrica y orientación adecuada, ...
Reis, Elias Moura
2005-01-01
En el contexto de desarrollo rural se sitúa el presente trabajo donde se pretenden analizar los câmbios e impactos generados por el Proyecto Gavião, financiado con recursos dei Fondo Internacional de Desarrollo Agrícola - FIDA, y dei Gobiemo dei Estado de Bahia. El Proyecto fue concebido considerando, además de los aspectos econômicos, los aspectos sociales, políticos, ambientales y culturales, así como la participación de los productores, sus familias y organizaciones en la definición y ejec...
Johanna García; Fabiola Hernández; Glacelidys Rodríguez; Neil Mago
2010-01-01
Los Desechos Sólidos Hospitalarios (DSH), contienen agentes patógenos o infecto-contagiosos, que representan un riesgo potencial para el personal que labora en las instituciones de salud, los pacientes y público en general. En consecuencia, el presente estudio tiene por finalidad diagnosticar la situación actual del manejo de los desechos sólidos generados en el Hospital “Dr. Julio Criollo Rivas”, en Ciudad Bolívar - estado Bolívar, durante el último semestre del año 2007, a través de una inv...
Effects of strength training on mechanomyographic amplitude
International Nuclear Information System (INIS)
The aim of the present study was to determine if the patterns of mechanomyographic (MMG) amplitude across force would change with strength training. Twenty-two healthy men completed an 8-week strength training program. During three separate testing visits (pre-test, week 4, and week 8), the MMG signal was detected from the vastus lateralis as the subjects performed isometric step muscle actions of the leg extensors from 10–100% of maximal voluntary contraction (MVC). During pre-testing, the MMG amplitude increased linearly with force to 66% MVC and then plateaued. Conversely, weeks 4 and 8 demonstrated an increase in MMG amplitude up to ∼85% of the subject's original MVC before plateauing. Furthermore, seven of the ten force levels (30–60% and 80–100%) showed a significant decrease in mean MMG amplitude values after training, which consequently led to a decrease in the slope of the MMG amplitude/force relationship. The decreases in MMG amplitude at lower force levels are indicative of hypertrophy, since fewer motor units would be required to produce the same absolute force if the motor units increased in size. However, despite the clear changes in the mean values, analyses of individual subjects revealed that only 55% of the subjects demonstrated a significant decrease in the slope of the MMG amplitude/force relationship. (paper)
Community Media: Muting the Democratic Media Discourse?
Carpentier, N.; Lie, R.; Servaes, J.
2003-01-01
Focuses on the concept of community media. Components that construct the identity of community media; Multi-theoretical approaches for analysis of community media; Definition of community media based on the concept of alternative media; Link between community media and civil society; Problems faced
From Augmentation Media to Meme Media.
Tanaka, Yuzuru
Computers as meta media are now evolving from augmentation media vehicles to meme media vehicles. While an augmentation media system provides a seamlessly integrated environment of various tools and documents, meme media system provides further functions to edit and distribute tools and documents. Documents and tools on meme media can easily…
Willis, E; Strasburger, V C
1998-04-01
American media are the most violent in the world, and American society is now paying a high price in terms of real life violence. Research has confirmed that mass media violence contributes to aggressive behavior, fear, and desensitization of violence. Television, movies, music videos, computer/video games are pervasive media and represent important influences on children and adolescents. Portraying rewards and punishments and showing the consequences of violence are probably the two most essential contextual factors for viewers as they interpret the meaning of what they are viewing on television. Public health efforts have emphasized public education, media literacy campaign for children and parents, and an increased use of technology to prevent access to certain harmful medial materials. PMID:9568012
Weller, Katrin; Meckel, Martin Sebastian; Stahl, Matthias
2013-01-01
Anlässlich der 10. Wissenschaftlichen Tagung „Soziale Medien“ am 27. und 28. Juni 2013 im Statistischen Bundesamt in Wiesbaden und in Fortsetzung des 2010 erschienenen Recherche Spezial Web 2.0 – Alle machen mit! werden in dieser Ausgabe in sechs Kapiteln Nachweise zu Veröffentlichungen und Forschungsprojekte der letzten drei Jahre zusammengestellt, die sich mit der Rolle von Social Media in verschiedenen Nutzungskontexten befassen. Social-Media-Dienste sind mittlerweile fester Bestandtei...
Softness and Amplitudes' Positivity for Spinning Particles
Bellazzini, Brando
2016-01-01
We derive positivity bounds for scattering amplitudes of particles with arbitrary spin using unitarity, analyticity and crossing symmetry. The bounds imply the positivity of certain low-energy coefficients of the effective action that controls the dynamics of the light degrees of freedom. We show that low-energy amplitudes strictly softer than $O(p^4)$ do not admit unitary ultraviolet completions unless the theory is free. This enforces a bound on the energy growth of scattering amplitudes in the region of validity of the effective theory. We discuss explicit examples including the Goldstino from spontaneous supersymmetry breaking, and the theory of a spin-1/2 fermion with a shift symmetry.
Multigluon helicity amplitudes involving a quark loop
Mahlon, G
1994-01-01
We apply the solution to the recursion relation for the double-off-shell quark current to the problem of computing one loop amplitudes with an arbitrary number of gluons. We are able to compute amplitudes for photon-gluon scattering, electron-positron annihilation to gluons, and gluon-gluon scattering via a quark loop in the case of like-helicity gluons. In addition, we present the result for the one-loop gluon-gluon scattering amplitude when one of the gluons has opposite helicity from the others.
Form Factor and Boundary Contribution of Amplitude
Huang, Rijun; Feng, Bo
2016-01-01
The boundary contribution of an amplitude in the BCFW recursion relation can be considered as a form factor involving boundary operator and unshifted particles. At the tree-level, we show that by suitable construction of Lagrangian, one can relate the leading order term of boundary operators to some composite operators of N=4 super-Yang-Mills theory, then the computation of form factors is translated to the computation of amplitudes. We compute the form factors of these composite operators through the computation of corresponding double trace amplitudes.
Motivic multiple zeta values and superstring amplitudes
International Nuclear Information System (INIS)
The structure of tree-level open and closed superstring amplitudes is analyzed. For the open superstring amplitude we find a striking and elegant form, which allows one to disentangle its α′-expansion into several contributions accounting for different classes of multiple zeta values. This form is bolstered by the decomposition of motivic multiple zeta values, i.e. the latter encapsulate the α′-expansion of the superstring amplitude. Moreover, a morphism induced by the coproduct maps the α′-expansion onto a non-commutative Hopf algebra. This map represents a generalization of the symbol of a transcendental function. In terms of elements of this Hopf algebra the α′-expansion assumes a very simple and symmetric form, which carries all the relevant information. Equipped with these results we can also cast the closed superstring amplitude into a very elegant form. (paper)
Off-shell amplitudes in superstring theory
Energy Technology Data Exchange (ETDEWEB)
Sen, Ashoke [Harish-Chandra Research Institute, Chhatnag Road, Jhusi, Allahabad, 211019 (India)
2015-04-01
Computing the renormalized masses and S-matrix elements in string theory, involving states whose masses are not protected from quantum corrections, requires defining off-shell amplitude with certain factorization properties. While in the bosonic string theory one can in principle construct such an amplitude from string field theory, there is no fully consistent field theory for type II and heterotic string theory. In this paper we give a practical construction of off-shell amplitudes satisfying the desired factorization property using the formalism of picture changing operators. We describe a systematic procedure for dealing with the spurious singularities of the integration measure that we encounter in superstring perturbation theory. This procedure is also useful for computing on-shell amplitudes, as we demonstrate by computing the effect of Fayet-Iliopoulos D-terms in four dimensional heterotic string theory compactifications using this formalism. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
The singular behavior of massive QCD amplitudes
International Nuclear Information System (INIS)
We discuss the structure of infrared singularities in on-shell QCD amplitudes with massive partons and present a general factorization formula in the limit of small parton masses. The factorization formula gives rise to an all-order exponentiation of both, the soft poles in dimensional regularization and the large collinear logarithms of the parton masses. Moreover, it provides a universal relation between any on-shell amplitude with massive external partons and its corresponding massless amplitude. For the form factor of a heavy quark we present explicit results including the fixed-order expansion up to three loops in the small mass limit. For general scattering processes we show how our constructive method applies to the computation of all singularities as well as the constant (mass-independent) terms of a generic massive n-parton QCD amplitude up to the next-to-next-to-leading order corrections. (orig.)
Amplitudes for left-handed strings
Siegel, W
2015-01-01
We consider a class of string-like models introduced previously where all modes are left-handed, all states are massless, T-duality is manifest, and only a finite number of orders in the string tension can appear. These theories arise from standard string theories by a singular gauge limit and associated change in worldsheet boundary conditions. In this paper we show how to calculate amplitudes by using the gauge parameter as an infrared regulator. The amplitudes produce the Cachazo-He-Yuan delta-functions after some modular integration; the Mason-Skinner string-like action and amplitudes arise from the zero-tension (infinite-slope) limit. However, without the limit the amplitudes have the same problems as found in the Mason-Skinner formalism.
Open string amplitudes of closed topological vertex
Takasaki, Kanehisa
2016-01-01
The closed topological vertex is the simplest "off-strip" case of non-compact toric Calabi-Yau threefolds with acyclic web diagrams. By the diagrammatic method of topological vertex, open string amplitudes of topological string theory therein can be obtained by gluing a single topological vertex to an "on-strip" subdiagram of the tree-like web diagram. If non-trivial partitions are assigned to just two parallel external lines of the web diagram, the amplitudes can be calculated with the aid of techniques borrowed from the melting crystal models. These amplitudes are thereby expressed as matrix elements, modified by simple prefactors, of an operator product on the Fock space of 2D charged free fermions. This fermionic expression can be used to derive $q$-difference equations for generating functions of special subsets of the amplitudes. These $q$-difference equations may be interpreted as the defining equation of a quantum mirror curve.
Holomorphic Factorization of Superstring Scattering Amplitudes
Institute of Scientific and Technical Information of China (English)
Simon Davis
2011-01-01
The holomorphic factorization of the superstring partition function is verified at arbitrary genus.The evaluation of scattering amplitudes and the implications of genus-dependent estimates on the string coupling are given.
Lectures on Scattering Amplitudes in String Theory
Staessens, Wieland
2010-01-01
In these lecture notes, we take a closer look at the calculation of scattering amplitudes for the bosonic string. It is believed that string theories form the UV completions of (super)gravity theories. Support for this claim can be found in the (on-shell) scattering amplitudes of strings. On the other hand, studying these string scattering amplitudes opens a window on the UV behavior of the string theories themselves. In these short set of lectures, we discuss the two-dimensional Polyakov path integral for the string, and its gauge symmetries, the connection to Riemann surfaces and how to obtain some of the simplest string scattering amplitudes. We end with some comments on more advanced topics. For simplicity we limit ourselves to bosonic open string theory in 26 dimensions.
Open string amplitudes of closed topological vertex
International Nuclear Information System (INIS)
The closed topological vertex is the simplest ‘off-strip’ case of non-compact toric Calabi–Yau threefolds with acyclic web diagrams. By the diagrammatic method of topological vertex, open string amplitudes of topological string theory therein can be obtained by gluing a single topological vertex to an ‘on-strip’ subdiagram of the tree-like web diagram. If non-trivial partitions are assigned to just two parallel external lines of the web diagram, the amplitudes can be calculated with the aid of techniques borrowed from the melting crystal models. These amplitudes are thereby expressed as matrix elements, modified by simple prefactors, of an operator product on the Fock space of 2D charged free fermions. This fermionic expression can be used to derive q-difference equations for generating functions of special subsets of the amplitudes. These q-difference equations may be interpreted as the defining equation of a quantum mirror curve. (paper)
Stora's fine notion of divergent amplitudes
Várilly, Joseph C
2016-01-01
Stora and coworkers refined the notion of divergent quantum amplitude, somewhat upsetting the standard power-counting recipe. This unexpectedly clears the way to new prototypes for free and interacting field theories of bosons of any mass and spin.
Effective gluon interactions from superstring disk amplitudes
Energy Technology Data Exchange (ETDEWEB)
Oprisa, D.
2006-05-15
In this thesis an efficient method for the calculation of the N-point tree-level string amplitudes is presented. Furthermore it is shown that the six-gluon open-superstring disk amplitude can be expressed by a basis of six triple hypergeometric functions, which encode the full {alpha}' dependence. In this connection material for obtaining the {alpha}' expansion of these functions is derived. Hereby many Euler-Zagier sums are calculated including multiple harmonic series. (HSI)
Path integral evaluation of Dbrane amplitudes
Chaudhuri, Shyamoli
1999-01-01
We extend Polchinski's evaluation of the measure for the one-loop closed string path integral to open string tree amplitudes with boundaries and crosscaps embedded in Dbranes. We explain how the nonabelian limit of near-coincident Dbranes emerges in the path integral formalism. We give a careful path integral derivation of the cylinder amplitude including the modulus dependence of the volume of the conformal Killing group.
Effective gluon interactions from superstring disk amplitudes
International Nuclear Information System (INIS)
In this thesis an efficient method for the calculation of the N-point tree-level string amplitudes is presented. Furthermore it is shown that the six-gluon open-superstring disk amplitude can be expressed by a basis of six triple hypergeometric functions, which encode the full α' dependence. In this connection material for obtaining the α' expansion of these functions is derived. Hereby many Euler-Zagier sums are calculated including multiple harmonic series. (HSI)
Employing Helicity Amplitudes for Resummation in SCET
Moult, Ian; Tackmann, Frank J; Waalewijn, Wouter J
2016-01-01
Helicity amplitudes are the fundamental ingredients of many QCD calculations for multi-leg processes. We describe how these can seamlessly be combined with resummation in Soft-Collinear Effective Theory (SCET), by constructing a helicity operator basis for which the Wilson coefficients are directly given in terms of color-ordered helicity amplitudes. This basis is crossing symmetric and has simple transformation properties under discrete symmetries.
Quartic amplitudes for Minkowski higher spin
Bengtsson, Anders K H
2016-01-01
The problem of finding general quartic interaction terms between fields of higher helicities on the light-front is discussed from the point of view of calculating the corresponding amplitudes directly from the cubic vertices using BCFW recursion. Amplitude based no-go results that has appeared in the literature are reviewed and discussed and it is pointed out how they may perhaps be circumvented.
Transient elasticity and polymeric fluids: Small-amplitude deformations.
Müller, Oliver; Liu, Mario; Pleiner, Harald; Brand, Helmut R
2016-02-01
Transient elasticity (TE) is a concept useful for a systematic generalization of viscoelasticity. Due to its thermodynamic consistency, it naturally leads to a simple description of non-Newtonian effects displayed by polymeric fluids, granular media, and other soft matter. We employ a continuum-mechanical theory that is derived from TE and tailored to polymeric fluids, showing how it captures a surprisingly large number of phenomena in shear and elongational flows, including stationary, oscillatory, and transient ones, as well as the flow down an inclined channel. Even the Weissenberg effect is well accounted for. This theory is applicable for small- as well as large-amplitude deformations. We concentrate on the former in the present article, leaving the latter to a companion article. PMID:26986419
Energy Technology Data Exchange (ETDEWEB)
Salazar Villalpando, Maria Dolores [Instituto Mexicano del Petroleo, Mexico, D. F. (Mexico)
1992-12-31
In general terms, there are only three ways of avoiding the sulfur dioxide and the nitrogen oxides, generated by the combustion in open chamber, from contaminating the air; the first one is utilizing low sulfur and nitrogen content fuels, the second one is by controlling the parameters that affect the combustion and the third one to treat and/or clean the gases before exhausting them to the air. In this document, some of the treatments for diminishing the pollutant emissions generated by the combustion in open chamber, are presented. [Espanol] En terminos generales, solo existen 3 maneras de evitar que el dioxido de azufre y oxidos de nitrogeno generados por la combustion en camara abierta sigan contaminando el aire, la primera es utilizar un combustible de bajo contenido de azufre y nitrogeno, la segunda es controlar los parametros que afectan la combustion, y la tercera es tratar y/o limpiar los gases antes de emitirlos a la atmosfera. En este documento se presentan algunos tratamientos para disminuir las emisiones de contaminantes generados por la combustion en camara abierta.
Relations between closed string amplitudes at higher-order tree level and open string amplitudes
International Nuclear Information System (INIS)
KLT relations almost factorize closed string amplitudes on S2 by two open string tree amplitudes which correspond to the left- and the right-moving sectors. In this paper, we investigate string amplitudes on D2 and RP2. We find that KLT factorization relations do not hold in these two cases. The relations between closed and open string amplitudes have new forms. On D2 and RP2, the left- and the right-moving sectors are connected into a single sector. Then an amplitude with closed strings on D2 or RP2 can be given by one open string tree amplitude except for a phase factor. The relations depends on the topologies of the world-sheets. Under T-duality, the relations on D2 and RP2 give the amplitudes between closed strings scattering from D-brane and O-plane respectively by open string partial amplitudes. In the low energy limits of these two cases, the factorization relations for graviton amplitudes do not hold. The amplitudes for gravitons must be given by the new relations instead.
Relations between closed string amplitudes at higher-order tree level and open string amplitudes
Energy Technology Data Exchange (ETDEWEB)
Chen Yixin, E-mail: yxchen@zimp.zju.edu.c [Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou 310027 (China); Du Yijian, E-mail: yjdu@zju.edu.c [Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou 310027 (China); Ma Qian, E-mail: mathons@gmail.co [Zhejiang Institute of Modern Physics, Zhejiang University, Hangzhou 310027 (China)
2010-01-01
KLT relations almost factorize closed string amplitudes on S{sub 2} by two open string tree amplitudes which correspond to the left- and the right-moving sectors. In this paper, we investigate string amplitudes on D{sub 2} and RP{sub 2}. We find that KLT factorization relations do not hold in these two cases. The relations between closed and open string amplitudes have new forms. On D{sub 2} and RP{sub 2}, the left- and the right-moving sectors are connected into a single sector. Then an amplitude with closed strings on D{sub 2} or RP{sub 2} can be given by one open string tree amplitude except for a phase factor. The relations depends on the topologies of the world-sheets. Under T-duality, the relations on D{sub 2} and RP{sub 2} give the amplitudes between closed strings scattering from D-brane and O-plane respectively by open string partial amplitudes. In the low energy limits of these two cases, the factorization relations for graviton amplitudes do not hold. The amplitudes for gravitons must be given by the new relations instead.
Relations between closed string amplitudes at higher-order tree level and open string amplitudes
Chen, Yi-Xin; Du, Yi-Jian; Ma, Qian
2010-01-01
KLT relations almost factorize closed string amplitudes on S by two open string tree amplitudes which correspond to the left- and the right-moving sectors. In this paper, we investigate string amplitudes on D and RP. We find that KLT factorization relations do not hold in these two cases. The relations between closed and open string amplitudes have new forms. On D and RP, the left- and the right-moving sectors are connected into a single sector. Then an amplitude with closed strings on D or RP can be given by one open string tree amplitude except for a phase factor. The relations depends on the topologies of the world-sheets. Under T-duality, the relations on D and RP give the amplitudes between closed strings scattering from D-brane and O-plane respectively by open string partial amplitudes. In the low energy limits of these two cases, the factorization relations for graviton amplitudes do not hold. The amplitudes for gravitons must be given by the new relations instead.
CERN. Geneva
2009-01-01
With the LHC starting up soon, the world's media are again turning their attention to CERN. We're all likely to be called upon to explain what is happening at CERN to media, friends and neighbours. The seminar will be given by BBC television news journalists Liz Pike and Nadia Marchant, and will deal with the kind of questions we're likely to be confronted with through the restart period. The training is open for everybody. Make sure you arrive early enough to get a seat - there are only 200 seats in the Globe. The session will also be webcast: http://webcast.cern.ch/
Scattering amplitudes in open superstring theory
International Nuclear Information System (INIS)
The present thesis deals with the theme field of the scattering amplitudes in theories of open superstrings. Especially two different formalisms for the handling of superstrings are introduced and applied for the calaculation of tree-level amplitudes - the Ramond- Neveu-Schwarz (RNS) and the Pure-Spinor (PS) formalism. The RNS approach is proved as flexible in order to describe compactification of the initially ten flat space-time dimensions to four dimensions. We solve the technical problems, which result from the interacting basing world-sheet theory with conformal symmetry. This is used to calculate phenomenologically relevant scattering amplitudes of gluons and quarks as well as production rates of massive harmonic vibrations, which were already identified as virtual exchange particles on the massless level. In the case of a low string mass scale in the range of some Tev the string-specific signatures in parton collisions can be observed in the near future in the LHC experiment at CERN and indicated as first experimental proof of the string theory. THose string effects occur universally for a wide class of string ground states respectively internal geometries and represent an elegant way to avoid the so-called landscape problem of the string theory. A further theme complex in this thesis is based on the PS formalism, which allows a manifestly supersymmetric treatment of scattering amplitudes in ten space-time dimension with sixteen supercharges. We introduce a family of superfields, which occur in massless amplitudes of the open string and can be naturally identified with diagrams of three-valued knots. Thereby we reach not only a compact superspace representation of the n-point field-theory amplitude but can also write the complete superstring n-point amplitude as minimal linear combination of partial amplitudes of the field theory as well as hypergeometric functions. The latter carry the string effects and are analyzed from different perspectives, above all
Scattering amplitudes in open superstring theory
Energy Technology Data Exchange (ETDEWEB)
Schlotterer, Oliver
2011-07-15
The present thesis deals with the theme field of the scattering amplitudes in theories of open superstrings. Especially two different formalisms for the handling of superstrings are introduced and applied for the calaculation of tree-level amplitudes - the Ramond- Neveu-Schwarz (RNS) and the Pure-Spinor (PS) formalism. The RNS approach is proved as flexible in order to describe compactification of the initially ten flat space-time dimensions to four dimensions. We solve the technical problems, which result from the interacting basing world-sheet theory with conformal symmetry. This is used to calculate phenomenologically relevant scattering amplitudes of gluons and quarks as well as production rates of massive harmonic vibrations, which were already identified as virtual exchange particles on the massless level. In the case of a low string mass scale in the range of some Tev the string-specific signatures in parton collisions can be observed in the near future in the LHC experiment at CERN and indicated as first experimental proof of the string theory. THose string effects occur universally for a wide class of string ground states respectively internal geometries and represent an elegant way to avoid the so-called landscape problem of the string theory. A further theme complex in this thesis is based on the PS formalism, which allows a manifestly supersymmetric treatment of scattering amplitudes in ten space-time dimension with sixteen supercharges. We introduce a family of superfields, which occur in massless amplitudes of the open string and can be naturally identified with diagrams of three-valued knots. Thereby we reach not only a compact superspace representation of the n-point field-theory amplitude but can also write the complete superstring n-point amplitude as minimal linear combination of partial amplitudes of the field theory as well as hypergeometric functions. The latter carry the string effects and are analyzed from different perspectives, above all
Amplitude scaling of asymmetry-induced transport
International Nuclear Information System (INIS)
Our initial experiments on asymmetry-induced transport in non-neutral plasmas found the radial particle flux at small radii to be proportional to φa2, where φa is the applied asymmetry amplitude. Other researchers, however, using the global expansion rate as a measure of the transport, have observed a φa1 scaling when the rigidity (the ratio of the axial bounce frequency to the azimuthal rotation frequency) is in the range one to ten. In an effort to resolve this discrepancy, we have extended our measurements to different radii and asymmetry frequencies. Although the results to date are generally in agreement with those previously reported (φa2 scaling at low asymmetry amplitudes falling off to a weaker scaling at higher amplitudes), we have observed some cases where the low amplitude scaling is closer to φa1. Both the φa2 and φa1 cases, however, have rigidities less than ten. Instead, we find that the φa1 cases are characterized by an induced flux that is comparable in magnitude but opposite in sign to the background flux. This suggests that the mixing of applied and background asymmetries plays an important role in determining the amplitude scaling of this transport
Pulley, John
2009-01-01
At a time when the evolutionary pace of new media resembles the real-time mutation of certain microorganisms, the age-old question of how best to connect with constituents can seem impossibly complex--even for an elite institution plugged into the motherboard of Silicon Valley. Identifying the most effective vehicle for reaching a particular…
Pels, D.
2008-01-01
The present article compendiously presents the interlinked and abruptly developing processes of media democracy and political matters’ personalization. The writer expressly opts for these processes which can radically rejuvenate communication and trust among citizens and politicians and therefore reinforce, up to a certain extend, modern democracy’s function itself.
Perturbative type II amplitudes for BPS interactions
Basu, Anirban
2015-01-01
We consider the perturbative contributions to the R^4, D^4 R^4 and D^6 R^4 interactions in toroidally compactified type II string theory. These BPS interactions do not receive perturbative contributions beyond genus three. We derive Poisson equations satisfied by these moduli dependent string amplitudes. These T--duality invariant equations have eigenvalues that are completely determined by the structure of the integrands of the multi--loop amplitudes. The source terms are given by boundary terms of the moduli space of Riemann surfaces corresponding to both separating and non--separating nodes. These are determined directly from the string amplitudes, as well as from the logarithmic divergences of maximal supergravity. We explicitly solve these Poisson equations in nine and eight dimensions.
Scaling of saturation amplitudes in baroclinic instability
International Nuclear Information System (INIS)
By using finite-amplitude conservation laws for pseudomomentum and pseudoenergy, rigorous upper bounds have been derived on the saturation amplitudes in baroclinic instability for layered and continuously-stratified quasi-geostrophic models. Bounds have been obtained for both the eddy energy and the eddy potential enstrophy. The bounds apply to conservative (inviscid, unforced) flow, as well as to forced-dissipative flow when the dissipation is proportional to the potential vorticity. This approach provides an efficient way of extracting an analytical estimate of the dynamical scalings of the saturation amplitudes in terms of crucial non-dimensional parameters. A possible use is in constructing eddy parameterization schemes for zonally-averaged climate models. The scaling dependences are summarized, and compared with those derived from weakly-nonlinear theory and from baroclinic-adjustment estimates
Amplitude-modulated fiber-ring laser
DEFF Research Database (Denmark)
Caputo, J. G.; Clausen, Carl A. Balslev; Sørensen, Mads Peter;
2000-01-01
Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self-starting......Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self......-starting of stable solitonic pulses from small random noise, provided the modulation depth is small. The perturbative analysis leads to a nonlinear coupled return map for the amplitude, phase, and position of the soliton pulses circulating in the fiber-ring laser. We established the validity of this approach...
Relativistic amplitudes in terms of wave functions
International Nuclear Information System (INIS)
In the framework of the invariant diagram technique which arises at the formulation of the fueld theory on the light front the question about conditions at which the relativistic amplitudes may be expressed through the wave functions is investigated. The amplitudes obtained depend on four-vector ω, determining the light front surface. The way is shown to find such values of the four-vector ω, at which the contribution of diagrams not expressed through wave functions is minimal. The investigation carried out is equivalent to the study of the dependence of amplitudes of the old-fashioned perturbation theory in the in the infinite momentum frame on direction of the infinite momentum
Analytic Representations of Yang-Mills Amplitudes
Bjerrum-Bohr, N E J; Damgaard, Poul H; Feng, Bo
2016-01-01
Scattering amplitudes in Yang-Mills theory can be represented in the formalism of Cachazo, He and Yuan (CHY) as integrals over an auxiliary projective space---fully localized on the support of the scattering equations. Because solving the scattering equations is difficult and summing over the solutions algebraically complex, a method of directly integrating the terms that appear in this representation has long been sought. We solve this important open problem by first rewriting the terms in a manifestly Mobius-invariant form and then using monodromy relations (inspired by analogy to string theory) to decompose terms into those for which combinatorial rules of integration are known. The result is a systematic procedure to obtain analytic, covariant forms of Yang-Mills tree-amplitudes for any number of external legs and in any number of dimensions. As examples, we provide compact analytic expressions for amplitudes involving up to six gluons of arbitrary helicities.
Duality and effective amplitudes in quantum chromodynamics
International Nuclear Information System (INIS)
This work is an attempt to relate the partonic and hadronic phases of strong interactions by means of a model of effective string amplitudes which take into account color coherence without the need to restrict the phase-space. The basic idea of this approach is to construct, from open superstrings, string amplitudes which give, at the zero slope limit, QCD amplitudes. The running parameters (coupling and slope) of the model are constrained by perturbative QCD and by the consistency of string quantization. When the running slope becomes equal to the hadronic one, the model can be used in the hadronic sector. This approach could provide some hints about the effective string theory of QCD, and a better understanding of the parton-hadron duality
On Arbitrary Phases in Quantum Amplitude Amplification
Hoyer, P
2000-01-01
We consider the use of arbitrary phases in quantum amplitude amplification which is a generalization of quantum searching. We prove that the phase condition in amplitude amplification is given by $\\tan(\\phi/2)=\\tan(\\phi/2)(1-2a)$, where $\\phi$ and $\\phi$ are the phases used and where $a$ is the success probability of the given algorithm. Thus the choice of phases depends nontrivially and nonlinearly on the success probability. Utilizing this condition, we give methods for constructing quantum algorithms that succeed with certainty and for implementing arbitrary rotations. We also conclude that phase errors of order up to $\\frac{1}{\\sqrt{a}}$ can be tolerated in amplitude amplification.
Connecting physical resonant amplitudes and lattice QCD
Bolton, Daniel R.; Briceño, Raúl A.; Wilson, David J.
2016-06-01
We present a determination of the isovector, P-wave ππ scattering phase shift obtained by extrapolating recent lattice QCD results from the Hadron Spectrum Collaboration using mπ = 236 MeV. The finite volume spectra are described using extensions of Lüscher's method to determine the infinite volume Unitarized Chiral Perturbation Theory scattering amplitude. We exploit the pion mass dependence of this effective theory to obtain the scattering amplitude at mπ = 140 MeV. The scattering phase shift is found to agree with experiment up to center of mass energies of 1.2 GeV. The analytic continuation of the scattering amplitude to the complex plane yields a ρ-resonance pole at Eρ = [ 755 (2) (1) (20 02) -i/2 129 (3) (1) (7 1) ] MeV. The techniques presented illustrate a possible pathway towards connecting lattice QCD observables of few-body, strongly interacting systems to experimentally accessible quantities.
Gluon scattering amplitudes at strong coupling
Alday, Luis F
2007-01-01
We describe how to compute planar gluon scattering amplitudes at strong coupling in N=4 super Yang Mills by using the gauge/string duality. The computation boils down to finding a certain classical string configuration whose boundary conditions are determined by the gluon momenta. The results are infrared divergent. We introduce the gravity version of dimensional regularization to define finite quantities. The leading and subleading IR divergencies are characterized by two functions of the coupling that we compute at strong coupling. We compute also the full finite form for the four point amplitude and we find agreement with a recent ansatz by Bern, Dixon and Smirnov.
Softness, Polynomial Boundedness and Amplitudes' Positivity
Bai, Dong
2016-01-01
In this note, we study the connection between infrared (IR) and ultraviolet (UV) behaviors of scattering amplitudes of massless channels by exploiting dispersion relations and positivity bounds. Given forward scattering amplitudes which scale as $\\mathcal{A}(s)\\sim s^M$ in the IR ($s\\to0$) and could be embedded into UV completions satisfying unitarity, analyticity, crossing symmetry and polynomial boundedness $|\\mathcal{A}(s)|< c\\, |s|^N$ ($|s|\\to\\infty$), with $M$ and $N$ integers, we show that the inequality $2\\ceil*{\\frac{N}{2}}\\ge M \\ge 0$ must hold, where $\\ceil*{x}$ is the smallest integer greater than or equal to $x$.
Fedorov, Alexander
2008-01-01
This monograph analyzes the theory and practice of media education and media literacy. The book also includes the list of Russian media education literature and addresses of websites of the associations for media education.
OME; Secretory otitis media; Serous otitis media; Silent otitis media; Silent ear infection; Glue ear ... drains from the tube and is swallowed. Otitis media with effusion (OME) and ear infections are connected ...
Fatigue Reliability under Multiple-Amplitude Loads
DEFF Research Database (Denmark)
Talreja, R.
1979-01-01
initial tensile strength and the fatigue life, the probability distributions for the residual tensile strength in both the crack initiation and the crack propagation stages of fatigue are determined. The method is illustrated for two-amplitude loads by means of experimental results obtained by testing...
On Calculation of Amplitudes in Quantum Electrodynamics
Karplyuk, Kostyantyn; Zhmudsky, Oleksandr
2012-01-01
A new method of calculation of amplitudes of different processes in quantum electrodynamics is proposed. The method does not use the Feynman technique of trace of product of matrices calculation. The method strongly simplifies calculation of cross sections for different processes. The effectiveness of the method is shown on the cross-section calculation of Coulomb scattering, Compton scattering and electron-positron annihilation.
Microwave Imaging using Amplitude-only Data
DEFF Research Database (Denmark)
Rubæk, Tonny; Zhurbenko, Vitaliy
2010-01-01
This paper discuss how the performance of an imaging system is affected when the phase information of the measurements are removed from the data, leaving only amplitude information as input for the imaging algorithm. Simulated data are used for this purpose, and the images resulting from using...
Amplitude Correction Factors of KVN Observations
Lee, Sang-Sung; Oh, Chung Sik; Kim, Hyo Ryoung; Kim, Jongsoo; Jung, Taehyun; Oh, Se-Jin; Roh, Duk-Gyoo; Jung, Dong-Kyu; Yeom, Jae-Hwan
2015-01-01
We report results of investigation of amplitude calibration for very long baseline interferometry (VLBI) observations with Korean VLBI Network (KVN). Amplitude correction factors are estimated based on comparison of KVN observations at 22~GHz correlated by Daejeon hardware correlator and DiFX software correlator in Korea Astronomy and Space Science Institute (KASI) with Very Long Baseline Array (VLBA) observations at 22~GHz by DiFX software correlator in National Radio Astronomy Observatory (NRAO). We used the observations for compact radio sources, 3C~454.3 and NRAO~512, which are almost unresolved for baselines in a range of 350-477~km. Visibility data of the sources obtained with similar baselines at KVN and VLBA are selected, fringe-fitted, calibrated, and compared for their amplitudes. We found that visibility amplitudes of KVN observations should be corrected by factors of 1.10 and 1.35 when correlated by DiFX and Daejeon correlators, respectively. These correction factors are attributed to the combinat...
Generalised Unitarity for Dimensionally Regulated Amplitudes
Bobadilla, W J Torres; Mastrolia, P; Mirabella, E
2015-01-01
We present a novel set of Feynman rules and generalised unitarity cut-conditions for computing one-loop amplitudes via d-dimensional integrand reduction algorithm. Our algorithm is suited for analytic as well as numerical result, because all ingredients turn out to have a four-dimensional representation. We will apply this formalism to NLO QCD corrections.
Connected formulas for amplitudes in standard model
He, Song
2016-01-01
Witten's twistor string theory has led to new representations of S-matrix in massless QFT as a single object, including Cachazo-He-Yuan formulas in general and connected formulas in four dimensions. As a first step towards more realistic processes of the standard model, we extend the construction to QCD tree amplitudes with massless quarks and those with a Higgs boson. For both cases, we find connected formulas in four dimensions for all multiplicities which are very similar to the one for Yang-Mills amplitudes. The formula for quark-gluon color-ordered amplitudes differs from the pure-gluon case only by a Jacobian factor that depends on flavors and orderings of the quarks. In the formula for Higgs plus multi-parton amplitudes, the massive Higgs boson is effectively described by two additional massless legs which do not appear in the Parke-Taylor factor. The latter also represents the first twistor-string/connected formula for form factors.
Holographic Corrections to the Veneziano Amplitude
Armoni, Adi
2016-01-01
We propose a holographic computation of the $2\\rightarrow 2$ meson scattering in a curved string background, dual to a QCD-like theory. We recover the Veneziano amplitude and compute a perturbative correction due to the background curvature. The result implies a small deviation from a linear trajectory, which is a requirement of the UV regime of QCD.
Media Education Initiatives by Media Organizations: The Uses of Media Literacy in Hong Kong Media
Chu, Donna; Lee, Alice Y. L.
2014-01-01
As more media organizations have engaged in media education, this paper investigates the goals and practices of these activities. This article coins media education initiatives by media organizations with the term "media-organization media literac"y (MOML). Four MOML projects in Hong Kong were selected for examination. Built on critical…
Puntos críticos sobre la reforma en Educación básica y media superior en México
Karina Rodríguez Cortés; Luis Ignacio Salgado Fernández
2009-01-01
Uno de los varios problemas que enfrenta la reforma en el diseño curricular de los niveles de educación básica y media superior en México, es el relacionado con la mediación de los docentes para el trabajo educativo y la evaluación del desarrollo de competencias de los educandos. A lo anterior se suma, la gran cantidad de materiales generados al respecto, en los que la Secretaría de Educación Pública intenta exponer desde un discurso oficial: qué son las competencias y lo que éstas implican p...
Ruales Salcedo, Angela Viviana
2015-01-01
En los últimos años se ha manifestado un interés creciente en el aprovechamiento de la biomasa generada como residuo de los procesos industriales, por su fácil accesibilidad y características físico-químicas. Este aprovechamiento, además de contribuir con el medio ambiente, está enfocado a dar o mejorar el valor económico de los residuos. En la producción y transformación de la uva son generados residuos que poseen características de interés para el uso agronómico, farmacéutico/cosmético y en...
Olmos Clavijo, Alba Ruth
2014-01-01
La investigación, a través de un proceso de articulación teórica presenta un marco analítico para el abordaje de los conflictos ambientales asociados al aprovisionamiento y regulación hídrica, generados por la expansión de cultivos de palma de aceite, desde un enfoque que pretende retomar el origen pedagógico del término “servicios ecosistémicos”. Es así como se acude al concepto de “beneficio ecosistémico” para realizar la lectura en contexto de las divergencias, a partir de las interrelacio...
Mery Letelier, Francisco Santiago
1998-01-01
La tesis doctoral aborda temáticamente la gestión integral de los residuos sanitarios, y la caracterización de residuos generados en distintos tipos de centros sanitarios (hospital, clínicas, laboratorios clínicos y clínica veterinaria), así como de residuos sólidos urbanos, a través de su composición, parámetros físicos como la humedad y la densidad, así como de indicadores microbiológicos, culminando en una propuesta de reglamentación aplicable a la gestión de residuos sanitarios....
Optical twists in phase and amplitude
DEFF Research Database (Denmark)
Daria, Vincent R.; Palima, Darwin; Glückstad, Jesper
2011-01-01
where both phase and amplitude express a helical profile as the beam propagates in free space. Such a beam can be accurately referred to as an optical twister. We characterize optical twisters and demonstrate their capacity to induce spiral motion on particles trapped along the twisters’ path. Unlike LG......Light beams with helical phase profile correspond to photons having orbital angular momentum (OAM). A Laguerre-Gaussian (LG) beam is an example where its helical phase sets a phase-singularity at the optical axis and forms a ring-shaped transverse amplitude profile. Here, we describe a unique beam...... beams, the far field projection of the twisted optical beam maintains a high photon concentration even at higher values of topological charge. Optical twisters have therefore profound applications to fundamental studies of light and atoms such as in quantum entanglement of the OAM, toroidal traps for...
Quadrupole and monopole large amplitude vibrations
International Nuclear Information System (INIS)
A set of nonlinear dynamical equations for quadrupole and monopole moments of nuclei is derived from the TDHF equation with the help of the so-called Wigner function moments. It allows the description of coupled large amplitude monopole and quadrupole vibrations. These equations are solved numerically for 208Pb and 40Ca in a model with separable forces. The giant quadrupole and monopole resonances are reproduced very well. However the essential feature of the large amplitude motion is the existence of multiphonon states. They are analyzed in detail. The classical and quantum aspects of the analytically solvable one-dimensional pure monopole model are studied to clarify the problem of the anharmonicity of the collective spectrum. 26 refs., 2 figs., 2 tabs
Differential equations, associators, and recurrences for amplitudes
Puhlfürst, Georg; Stieberger, Stephan
2016-01-01
We provide new methods to straightforwardly obtain compact and analytic expressions for ɛ-expansions of functions appearing in both field and string theory amplitudes. An algebraic method is presented to explicitly solve for recurrence relations connecting different ɛ-orders of a power series solution in ɛ of a differential equation. This strategy generalizes the usual iteration by Picard's method. Our tools are demonstrated for generalized hypergeometric functions. Furthermore, we match the ɛ-expansion of specific generalized hypergeometric functions with the underlying Drinfeld associator with proper Lie algebra and monodromy representations. We also apply our tools for computing ɛ-expansions for solutions to generic first-order Fuchsian equations (Schlesinger system). Finally, we set up our methods to systematically get compact and explicit α‧-expansions of tree-level superstring amplitudes to any order in α‧.
Planar scattering amplitudes from Wilson loops
International Nuclear Information System (INIS)
We derive an expression for parton scattering amplitudes of planar gauge theory in terms of sums of Wilson loops. We study in detail the example of Yang-Mills theory with an adjoint Higgs field. The expression exhibits the T-duality performed by Alday and Maldacena in the AdS dual as a Fourier transform in loop space. When combined with the AdS/CFT correspondence for Wilson loops and a strong coupling argument for the dominance of 1PI diagrams, this leads to a derivation of the Alday-Maldacena holographic prescription for scattering amplitudes in terms of momentum Wilson loops. The formula leads to a conjecture for a relationship between position-space and momentum-space Wilson loops in N = 4 SYM at finite coupling.
Differential Equations, Associators, and Recurrences for Amplitudes
Puhlfuerst, Georg
2015-01-01
We provide new methods to straightforwardly obtain compact and analytic expressions for epsilon-expansions of functions appearing in both field and string theory amplitudes. An algebraic method is presented to explicitly solve for recurrence relations connecting different epsilon-orders of a power series solution in epsilon of a differential equation. This strategy generalizes the usual iteration by Picard's method. Our tools are demonstrated for generalized hypergeometric functions. Furthermore, we match the epsilon-expansion of specific generalized hypergeometric functions with the underlying Drinfeld associator with proper Lie algebra and monodromy representations. We also setup up our tools for computing epsilon-expansions for solutions to generic first-order Fuchsian equations (Schlesinger system). Finally, we apply our methods to systematically get compact and explicit alpha'-expansions of tree-level superstring amplitudes to any order in alpha'.
Critical Initial Amplitude of Langmuir Wave Damping
Institute of Scientific and Technical Information of China (English)
徐慧; 盛政明
2012-01-01
By one-dimensional Vlasov-Poisson simulation, the critical initial state marking the transition between the Landau scenario, in which the electric fields definitively damped to zero and the O＇NEIL scenario, in which the Landau damping is stopped after a certain damping stage, is studied. It is found that the critical initial amplitude e＊ can only exist when the product of the wave number （k~） and the electron thermal velocity （vth） is moderate, that is, 0.2 〈 k~vth 〈 0.7. Otherwise, no critical initial amplitude is found. The value c＊ increases with the increase in km for a fixed Vth, and also increases with the increase in Vth for a fixed kin. When kmVth is fixed, the value s＊ also changes with the wave number and the electron thermal velocity, even though the damping rate and the oscillation frequency are the same in this case.
Differential equations, associators, and recurrences for amplitudes
Directory of Open Access Journals (Sweden)
Georg Puhlfürst
2016-01-01
Full Text Available We provide new methods to straightforwardly obtain compact and analytic expressions for ϵ-expansions of functions appearing in both field and string theory amplitudes. An algebraic method is presented to explicitly solve for recurrence relations connecting different ϵ-orders of a power series solution in ϵ of a differential equation. This strategy generalizes the usual iteration by Picard's method. Our tools are demonstrated for generalized hypergeometric functions. Furthermore, we match the ϵ-expansion of specific generalized hypergeometric functions with the underlying Drinfeld associator with proper Lie algebra and monodromy representations. We also apply our tools for computing ϵ-expansions for solutions to generic first-order Fuchsian equations (Schlesinger system. Finally, we set up our methods to systematically get compact and explicit α′-expansions of tree-level superstring amplitudes to any order in α′.
Integrable spin chains and scattering amplitudes
Energy Technology Data Exchange (ETDEWEB)
Bartels, J.; Prygarin, A. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Lipatov, L.N. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik; Petersburg Nuclear Physics Institute (Russian Federation); Sankt-Peterburgskij Univ., St. Petersburg (Russian Federation)
2011-04-15
In this review we show that the multi-particle scattering amplitudes in N=4 SYM at large N{sub c} and in the multi-Regge kinematics for some physical regions have the high energy behavior appearing from the contribution of the Mandelstam cuts in the complex angular momentum plane of the corresponding t-channel partial waves. These Mandelstam cuts or Regge cuts are resulting from gluon composite states in the adjoint representation of the gauge group SU(N{sub c}). In the leading logarithmic approximation (LLA) their contribution to the six point amplitude is in full agreement with the known two-loop result. The Hamiltonian for the Mandelstam states constructed from n gluons in LLA coincides with the local Hamiltonian of an integrable open spin chain. We construct the corresponding wave functions using the integrals of motion and the Baxter-Sklyanin approach. (orig.)
Source amplitudes for active exterior cloaking
International Nuclear Information System (INIS)
The active cloak comprises a discrete set of multipole sources that destructively interfere with an incident time harmonic scalar wave to produce zero total field over a finite spatial region. For a given number of sources and their positions in two dimensions it is shown that the multipole amplitudes can be expressed as infinite sums of the coefficients of the incident wave decomposed into regular Bessel functions. The field generated by the active sources vanishes in the infinite region exterior to a set of circles defined by the relative positions of the sources. The results provide a direct solution to the inverse problem of determining the source amplitudes. They also define a broad class of non-radiating discrete sources. (paper)
Media Clusters and Media Cluster Policies
Karlsson, Charlie; Picard, Robert
2011-01-01
Large media clusters have emerged in a limited number of large cities, characterizing the geographical concentration of the global media industry. This paper explores the reasons behind the localization patterns of media industries, the effect of the rapid advancement of Information and Communication Technologies (ICT) on media clusters and the role of media cluster policies. One might draw the conclusion that with the developments of the ICT sector and the fact that there are no raw material...
Subleading soft factor for string disk amplitudes
Schwab, Burkhard U. W.
2014-08-01
We investigate the behavior of superstring disk scattering amplitudes in the presence of a soft external momentum at finite string tension. We prove that there are no α'-corrections to the field theory form of the subleading soft factor S (1). At the end of this work, we also comment on the possibility to find the corresponding subleading soft factors in closed string theory using our result and the KLT relations.
Subleading Soft Factor for String Disk Amplitudes
Schwab, Burkhard U W
2014-01-01
We investigate the behavior of superstring disk scattering amplitudes in the presence of a soft external momentum at finite string tension. We prove that there are no $\\alpha'$-corrections to the field theory form of the subleading soft factor $S^{(1)}$. At the end of this work, we also comment on the possibility to find the corresponding subleading soft factors in closed string theory using our result and the KLT relations.
Automation of 2-loop Amplitude Calculations
Jones, S P
2016-01-01
Some of the tools and techniques that have recently been used to compute Higgs boson pair production at NLO in QCD are discussed. The calculation relies on the use of integral reduction, to reduce the number of integrals which must be computed, and expressing the amplitude in terms of a quasi-finite basis, which simplifies their numeric evaluation. Emphasis is placed on sector decomposition and Quasi-Monte Carlo (QMC) integration which are used to numerically compute the master integrals.
Amplitude Modulation and Loudness in Cochlear Implantees
McKay, Colette M.; Henshall, Katherine R.
2009-01-01
The effect of amplitude modulation of pulse trains on the loudness perceived by cochlear implantees was investigated for different overall levels of the signal, modulation depth and the carrier rate of the pulse train. Equally loud and threshold levels were determined for a variety of signal levels, modulation depths and carrier rates in six cochlear implantees. The pattern of results was consistent with the predictions of a previously published loudness model of McKay et al. (J Acoust Soc Am...
Amplitude modulation and loudness in cochlear implantees
McKay CM., Henshall KR.
2009-01-01
The effect of amplitude modulation of pulse trains on the loudness perceived by cochlear implantees was investigated for different overall levels of the signal, modulation depth and the carrier rate of the pulse train. Equally loud and threshold levels were determined for a variety of signal levels, modulation depths and carrier rates in six cochlear implantees. The pattern of results was consistent with the predictions of a previously published loudness model of McKay et al. (J Acoust Soc Am...
Inverse amplitude method and Adler zeros
Gómez Nicola, Ángel; Peláez Sagredo, José Ramón; Rios, G.
2008-01-01
The inverse amplitude method is a powerful unitarization technique to enlarge the energy applicability region of effective Lagrangians. It has been widely used to describe resonances in hadronic physics, combined with chiral perturbation theory, as well as in the strongly interacting symmetry breaking sector. In this work we show how it can be slightly modified to also account for the subthreshold region, incorporating correctly the Adler zeros required by chiral symmetry and eliminating spur...
On the infinities of closed superstring amplitudes
International Nuclear Information System (INIS)
We present an analysis of possible infinities that may be present in uncompactified multi-loop heterotic and type II superstring amplitudes constructed, without use of the short-string limit, in the light-cone gauge, and with use of a closed SUSY field theory algebra. Various types of degenerations of the integrand are discussed on the string world-sheet. No infinities are found, modulo (for type II) a particular identity for Green's functions. (author). 13 refs
Analytic amplitude models for forward scattering
Kang, K.; Cudell, Jean-René; Ezhela, V. V.; Gauron, P.; Kuyanov, Yu. V.; Lugovsky, S. V.; Nicolescu, B.; Tkachenko, N. P.
2001-01-01
We report on fits of a large class of analytic amplitude models for forward scattering against the comprehensive data for all available reactions. To differentiate the goodness of the fits of many possible parametrizations to a large sample of data, we developed and used a set of quantitative indicators measuring statistical quality of the fits over and beyond the typical criterion of the $\\Chi^2 /dof$. These indicators favor models with a universal $ log^2 s$ Pomeron term, which enables one ...
Transversity Amplitudes in Hypercharge Exchange Processes
International Nuclear Information System (INIS)
' In this work we present several techniques developed for the extraction of the. Transversity amplitudes governing quasi two-body meson baryon reactions with hypercharge exchange. We review the methods used in processes having a pure spin configuration, as well as the more relevant results obtained with data from Kp and Tp interactions at intermediate energies. The predictions of the additive quark model and the ones following from exchange degeneracy and etoxicity are discussed. We present a formalism for amplitude analysis developed for reactions with mixed spin configurations and discuss the methods of parametric estimation of the moduli and phases of the amplitudes, as well as the various tests employed to check the goodness of the fits. The calculation of the generalized joint density matrices is given and we propose a method based on the generalization of the idea of multipole moments, which allows to investigate the structure of the decay angular correlations and establishes the quality of the fits and the validity of the simplifying assumptions currently used in this type of studies. (Author) 43 refs
Connecting physical resonant amplitudes and lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Bolton, Daniel R. [Univ. of Colorado, Boulder, CO (United States); Baylor Univ., Waco, TX (United States); Briceño, Raúl A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Wilson, David J. [Old Dominion Univ., Norfolk, VA (United States)
2016-03-01
We present a determination of the isovector, $P$-wave $\\pi\\pi$ scattering phase shift obtained by extrapolating recent lattice QCD results from the Hadron Spectrum Collaboration using $m_\\pi =236$ MeV. The finite volume spectra are described using extensions of L\\"uscher's method to determine the infinite volume Unitarized Chiral Perturbation Theory scattering amplitude. We exploit the pion mass dependence of this effective theory to obtain the scattering amplitude at $m_\\pi= 140$ MeV. The scattering phase shift is found to be in good agreement with experiment up to center of mass energies of 1.2 GeV. The analytic continuation of the scattering amplitude to the complex plane yields a $\\rho$-resonance pole at $E_\\rho= \\left[755(2)(1)(^{20}_{02})-\\frac{i}{2}\\,129(3)(1)(^{7}_{1})\\right]~{\\rm MeV}$. The techniques presented illustrate a possible pathway towards connecting lattice QCD observables of few-body, strongly interacting systems to experimentally accessible quantities.
Amplitude-modulated fiber-ring laser
DEFF Research Database (Denmark)
Caputo, J. G.; Clausen, Carl A. Balslev; Sørensen, Mads Peter; Bischoff, Svend
2000-01-01
Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self-starting......Soliton pulses generated by a fiber-ring laser are investigated by numerical simulation and perturbation methods. The mathematical modeling is based on the nonlinear Schrödinger equation with perturbative terms. We show that active mode locking with an amplitude modulator leads to a self......-starting of stable solitonic pulses from small random noise, provided the modulation depth is small. The perturbative analysis leads to a nonlinear coupled return map for the amplitude, phase, and position of the soliton pulses circulating in the fiber-ring laser. We established the validity of this approach...... by comparison with the full numerical simulations. Finally, we discuss possible sources of instability that are due to resonances in the device....
Logarithmic Singularities and Maximally Supersymmetric Amplitudes
Bern, Zvi; Litsey, Sean; Stankowicz, James; Trnka, Jaroslav
2014-01-01
The dual formulation of planar N = 4 super-Yang-Mills scattering amplitudes makes manifest that the integrand has only logarithmic singularities and no poles at infinity. Recently, Arkani-Hamed, Bourjaily, Cachazo and Trnka conjectured the same singularity properties hold to all loop orders in the nonplanar sector as well. Here we conjecture that to all loop orders these constraints give us the key analytic information contained in dual conformal symmetry. We also conjecture that to all loop orders, while N = 8 supergravity has poles at infinity, at least at four points it has only logarithmic singularities at finite locations. We provide nontrivial evidence for these conjectures. For the three-loop four-point N = 4 super-Yang-Mills amplitude, we explicitly construct a complete basis of diagram integrands that has only logarithmic singularities and no poles at infinity. We then express the complete amplitude in terms of the basis diagrams, with the coefficients determined by unitarity. We also give examples a...
Lukinbeal, Chris
2014-01-01
While the use of media permeates geographic research and pedagogic practice, the underlying literacies that link geography and media remain uncharted. This article argues that geographic media literacy incorporates visual literacy, information technology literacy, information literacy, and media literacy. Geographic media literacy is the ability…
SAFETY IN ONLINE MEDIA – FREEDOM OF THE MEDIA; SAFETY OF MEDIA ACTORS AND MEDIA EDUCATION
Moeller, Ch
2013-01-01
In this paper, prepared for the international conference ‘Mass Media – Society – Education: Media Safety Problems’ at the Chelyabinsk State University’s Department for Journalism and Media Education from September 30 – October 3, 2013, I would like to address three dimensions of media safety and security in online media.
Transient waves in visco-elastic media
Ricker, Norman
1977-01-01
Developments in Solid Earth Geophysics 10: Transient Waves in Visco-Elastic Media deals with the propagation of transient elastic disturbances in visco-elastic media. More specifically, it explores the visco-elastic behavior of a medium, whether gaseous, liquid, or solid, for very-small-amplitude disturbances. This volume provides a historical overview of the theory of the propagation of elastic waves in solid bodies, along with seismic prospecting and the nature of seismograms. It also discusses the seismic experiments, the behavior of waves propagated in accordance with the Stokes wave
Second moment of the pion's distribution amplitude
International Nuclear Information System (INIS)
We present preliminary results from the QCDSF/UKQCD collaborations for the second moment of the pion's distribution amplitude with two flavours of dynamical fermions. We use nonperturbatively determined renormalisation coefficients to convert our results to the MS scheme at 5 GeV2. Employing a linear chiral extrapolation from our large pion masses > 550 MeV, we find left angle ξ2 right angle = 0.281(28), leading to a value of α2 = 0.236(82) for the second Gegenbauer moment. (orig.)
Second moment of the pion's distribution amplitude
International Nuclear Information System (INIS)
We present preliminary results from the QCDSF/UKQCD collaborations for the second moment of the pion's distribution amplitude with two flavours of dynamical fermions. We use nonperturbatively determined renormalisation coefficients to convert our results to the MS-bar scheme at 5GeV2. Employing a linear chiral extrapolation from our large pion masses >550MeV, we find 2>=0.281(28), leading to a value of a2=0.236(82) for the second Gegenbauer moment
Planar scattering amplitudes from Wilson loops
McGreevy, John; Sever, Amit
2008-01-01
We derive an expression for parton scattering amplitudes of planar gauge theory in terms of sums of Wilson loops. We study in detail the example of Yang-Mills theory with an adjoint Higgs field. The expression exhibits the T-duality performed by Alday and Maldacena in the AdS dual as a Fourier transform in loop space. When combined with the AdS/CFT correspondence for Wilson loops and a strong coupling argument for the dominance of 1PI diagrams, this leads to a derivation of the Alday-Maldacen...
Transition Distribution Amplitudes for gamma* gamma collisions
Lansberg, J P; Szymanowski, L
2008-01-01
We study the exclusive production of pi-pi and rho-pi in hard gamma* gamma scattering in the forward kinematical region where the virtuality of one photon provides us with a hard scale in the process. The newly introduced concept of Transition Distribution Amplitudes (TDA) is used to perform a QCD calculation of these reactions thanks to two simple models for TDAs. The sizable cross sections for rho-pi and pi-pi production may be tested at intense electron-positron colliders such as CLEO and B factories (Belle and BaBar).
Pion distribution amplitude within the instanton model
International Nuclear Information System (INIS)
The leading-twist pion distribution amplitude is obtained at a low normalization scale of an order of the inverse average size of an instanton ρc. The pion dynamics, consistent with gauge invariance and low energy theorems, is considered within the instanton vacuum model. The results are QCD evolved to higher momentum-transfer values, and are in agreement with recent data from CLEO on pion transition form factor. We also show that previous calculations violate the axial Ward-Takahashi identity
Relations and representations of QCD amplitudes
de la Cruz, Leonardo; Weinzierl, Stefan
2016-01-01
In this talk we review relations and representations of primitive QCD tree amplitudes. Topics covered include the BCJ relations, the CHY representation, and the KLT relations. We will put a special emphasis on how these relations and representations generalise from pure Yang-Mills theory to QCD. The generalisation of the KLT relations from pure Yang-Mills to QCD includes the case of massive quarks. On the gravity side we then obtain hypothetical particles interacting with gravitational strength, which can be massive and non-relativistic.
Inverse amplitude method and Adler zeros
International Nuclear Information System (INIS)
The inverse amplitude method is a powerful unitarization technique to enlarge the energy applicability region of effective Lagrangians. It has been widely used to describe resonances in hadronic physics, combined with chiral perturbation theory, as well as in the strongly interacting symmetry breaking sector. In this work we show how it can be slightly modified to also account for the subthreshold region, incorporating correctly the Adler zeros required by chiral symmetry and eliminating spurious poles. These improvements produce negligible effects on the physical region.
Approximate formulas for moderately small eikonal amplitudes
Kisselev, A V
2015-01-01
The eikonal approximation for moderately small scattering amplitudes is considered. With the purpose of using for their numerical estimations, the formulas are derived which contain no Bessel functions, and, hence, no rapidly oscillating integrands. To obtain these formulas, the improper integrals of the first kind which contain products of the Bessel functions J_0(z) are studied. The expression with four functions J_0(z) is generalized. The expressions for the integrals with the product of five and six Bessel functions J_0(z) are also found. The known formula for the improper integral with two functions J_nu(z) is generalized for non-integer nu.
A unified approach to string scattering amplitudes
International Nuclear Information System (INIS)
1) Physics. In the calculation of g-loop string tachion amplitudes with n scattering points the distinguished Polyakov measure dπg,n on the moduli space Mg,n of Riemann surfaces of genus g with n punctures arises. We give an interpretation of this measure as the modulus squared of a holomorphic section μg,n (the Mumford form) of a certain holomorphic line bundle, i.e., we prove an analog of the Belavin-Knizhnik theorem dπg,n=vertical strokeμγ,nvertical stroke2 in the amplitudic case. We give an expression for this measure through the determinants of the Laplace operators over ghosts and over multivalued fields with monodromy prescribed by impulses at the scattering points. We show also that the form μg,n (n≥0) for the partition function and n-point amplitudes can be obtained from a unified over all n, universal Mumford form. 2) Mathematics. The following new concepts from the theory of complex algebraic curves are investigated: Divisors with complex coefficients, complex powers of holomorphic line bundles, determinants of Laplace operators over multivalued functions, etc. The corresponding generalizations of the determinant line bundles, the Weil-Deligne pairings, the Quillen and the Arakelov-Deligne metrics are constructed. A suggested by string amplitude considerations analog of the Mumford theorem on holomorphic triviality of the bundle λ2xλ1-13 over the moduli space is given. This analog asserts the existence of a canonical flat metric on a certain line bundle λ2xλ1-13x(xν=113ν), O(Dν)>-1). There exist two differences: The latter bundle is not holomorphically trivial but has a canonical flat metric, and, being defined on the Teichmueller space Tg,n, this bundle can be pulled down only on an infinite-sheeted covering of the moduli space Mg,n. The universal isometries and the relative curvatures from the second part of the paper may be interesting, too. (orig.)
Media Literacy in Times of Media Divides
Directory of Open Access Journals (Sweden)
Kaja Žuran
2013-12-01
Full Text Available We live in a post-modern society, an information society, a society based around knowledge and participation, and above all in a media society. In a media culture where media holds a dominant position, we cannot overlook the emerging idea of a ‘media divide’ within the frame of media education, media literate individuals and the expansion of the traditional concept of media literacy. Firstly, we are in an era of technological revolution, and it is time to consider the meaning and function of media and how we experience it in our everyday life. Secondly, as a society we are subject to intense media invasion and we all need to learn how to use it to our benefit and apply a critical and autonomous perspective towards selecting media content. Otherwise the media divide between the media literate and illiterate will widen; but is there even a chance to overcome the supposed divide between those who are formally media educated and those who are not?
The Construction of Spin Foam Vertex Amplitudes
Directory of Open Access Journals (Sweden)
Eugenio Bianchi
2013-01-01
Full Text Available Spin foam vertex amplitudes are the key ingredient of spin foam models for quantum gravity. These fall into the realm of discretized path integral, and can be seen as generalized lattice gauge theories. They can be seen as an attempt at a 4-dimensional generalization of the Ponzano-Regge model for 3d quantum gravity. We motivate and review the construction of the vertex amplitudes of recent spin foam models, giving two different and complementary perspectives of this construction. The first proceeds by extracting geometric configurations from a topological theory of the BF type, and can be seen to be in the tradition of the work of Barrett, Crane, Freidel and Krasnov. The second keeps closer contact to the structure of Loop Quantum Gravity and tries to identify an appropriate set of constraints to define a Lorentz-invariant interaction of its quanta of space. This approach is in the tradition of the work of Smolin, Markopoulous, Engle, Pereira, Rovelli and Livine.
Phase transitions and large amplitude oscillations
International Nuclear Information System (INIS)
We studied the way how do large amplitude oscillations propagate in a one-dimensional viscous compressible flow governed by the Navier-Stokes equations. The model used a barotropic state law. This allows phase transitions, like in Van der Waals fluid. The oscillations obey to an integro-differential Cauchy problem of a new type. Due to the translational invariance, one consider here the solutions which do not depend on the (slow) space variable. They actually depend on a fast variable, and obey to a differential equation dw/dt = -grad I(W) on an infinite-dimensional manifold, where I denotes the internal energy per unit mass. Stable steady states correspond to local minima of I. It follows that states belonging to the spinodal phase are unstable with respect to large amplitude oscillations. It also gives an evidence for instability of stationary phase transitions when the pressures, although taking equal values in both phases, differ from the Maxwell value. This result was well known in a different context, when the capillarity is taken in account in the model but cannot be obtained in our case by using only a straightforward linearization technique for the Navier-Stokes equations, because of the strongly nonlinear nature of a phase transition. (author). 5 refs, 2 figs
Effective string amplitudes for hadronic physics
International Nuclear Information System (INIS)
We propose using the general structure and properties of conformal field theory amplitudes, in particular those defined on surfaces with boundaries, to explore effective string theory amplitudes for some hadronic processes. Two examples are considered to illustrate the approach. In one a natural mechanism for chiral symmetry breaking within the string picture is proposed. One consequence is that the vertex operator for pion emission (at zero momentum) behaves like a world-sheet current evaluated on the string boundary. This fact is used to rederive, in a more general setting, hadronic mass relations found in the early days of string theory by Lovelace, and Ademollo, Veneziano and Weinberg. In the second example, we derive the general structure of the form factor for the emission of a pomeron (interpreted as a closed string) from a meson or baryon. The result reconciles the interpretation of the pomeron as a closed string, emitted from the interior of the meson or baryon world-sheet, with the additive quark rules for total hadronic cross sections at high energies. (orig.)
Double unresolved approximations to multiparton scattering amplitudes
International Nuclear Information System (INIS)
We present approximations to tree-level multiparton scattering amplitudes which are appropriate when two partons are unresolved. These approximations are required for the analytic isolation of infrared singularities of n+2 parton scattering processes contributing to the next-to-next-to-leading order corrections to n jet cross sections. In each case the colour ordered matrix elements factorise and yield a function containing the singular factors multiplying the n-parton amplitudes. When the unresolved particles are colour unconnected, the approximations are simple products of the familiar eikonal and Altarelli-Parisi splitting functions used to describe single unresolved emission. However, when the unresolved particles are colour connected the factorisation is more complicated and we introduce new and general functions to describe the triple collinear and soft/collinear limits in addition to the known double soft gluon limits of Berends and Giele. As expected the triple collinear splitting functions obey an N=1 SUSY identity. To illustrate the use of these double unresolved approximations, we have examined the singular limits of the tree-level matrix elements for e+e- →5 partons when only three partons are resolved. When integrated over the unresolved regions of phase space, these expressions will be of use in evaluating the O(αs3) corrections to the three-jet rate in electron-positron annihilation. (orig.)
Getting superstring amplitudes by degenerating Riemann surfaces
Energy Technology Data Exchange (ETDEWEB)
Matone, Marco [Dipartimento di Fisica ' G. Galilei' and Istituto Nazionale di Fisica Nucleare, Universita di Padova, Via Marzolo 8, 35131 Padova (Italy); Volpato, Roberto, E-mail: volpato@itp.phys.ethz.c [Institut fuer Theoretische Physik, ETH Zuerich, 8093 Zuerich (Switzerland)
2010-11-01
We explicitly show how the chiral superstring amplitudes can be obtained through factorisation of the higher genus chiral measure induced by suitable degenerations of Riemann surfaces. This powerful tool also allows to derive, at any genera, consistency relations involving the amplitudes and the measure. A key point concerns the choice of the local coordinate at the node on degenerate Riemann surfaces that greatly simplifies the computations. As a first application, starting from recent ansaetze for the chiral measure up to genus five, we compute the chiral two-point function for massless Neveu-Schwarz states at genus two, three and four. For genus higher than three, these computations include some new corrections to the conjectural formulae appeared so far in the literature. After GSO projection, the two-point function vanishes at genus two and three, as expected from space-time supersymmetry arguments, but not at genus four. This suggests that the ansatz for the superstring measure should be corrected for genus higher than four.
Kempen, Petrus Cornelis
2011-01-01
The media can make or break a reputation. This being said, it seems to be essential for companies, governments and institutions to pay specific attention to corporate media management in their daily operations. However, this thesis shows that they often neglect to pay adequate attention to corporate media management. This is primarily due to the complexity of the corporate media process and corporate media management and the scope of a possible media impact. This thesis argues that corporate ...
D. Ali Arslan
2008-01-01
The media is one of the most important institutions in society. It is a reality that media play very substantial role in the production and social distribution of knowledge. In addition to that, mass media provides the greatest communication opportunities to the people. Also, contemporary media provides very distinctive weapons to obtain power, wealth and prestige in the society. If media owners and elites are so powerful, the identification of media elites is of great importance. Hence, this...
Chudán, Jakub
2013-01-01
The “Social media marketing” diploma thesis focuses on social media marketing, with an analysis of potential social media sites usage as the main goal. The theoretical part focuses on social media and social media marketing. The practical part contains a case study, in which social media marketing on Facebook is created. A strategy proposal is made, based on the case study, emphasizing suitable ways of a proper use of Facebook for marketing, identifying various hurdles that companies are faci...
Curran, James P.
2011-01-01
Media and Democracy addresses key topics and themes in relation to democratic theory, media and technology, comparative media studies, media and history, and the evolution of media research. For example: How does TV entertainment contribute to the democratic life of society? Why are Americans less informed about politics and international affairs than Europeans? How should new communications technology and globalisation change our understanding of the democratic role of the media? ...
Color-Kinematic Duality in ABJM Theory Without Amplitude Relations
Sivaramakrishnan, Allic
2014-01-01
We explicitly show that the Bern-Carrasco-Johansson color-kinematic duality holds at tree level through at least eight points in Aharony-Bergman-Jafferis-Maldacena theory with gauge group SU(N) x SU(N). At six points we give the explicit form of numerators in terms of amplitudes, displaying the generalized gauge freedom that leads to amplitude relations. However, at eight points no amplitude relations follow from the duality, so the diagram numerators are fixed unique functions of partial amplitudes. We provide the explicit amplitude-numerator decomposition and the numerator relations for eight-point amplitudes.
Energy Technology Data Exchange (ETDEWEB)
Carmona-Perales, L. G.; Carmona-Perales, R. B. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)
2000-12-01
Water closed conduits are commonly designed with special attention paid to pressure surges due to pumping failures. In some particular cases, such at the Rio Yaque-Guaymas water pipeline system, pressure surges due to pumping start up are as high and dangerous as those produced by pumping failures. New subroutines were thus developed and included in the Closed Conduit Flow Transient Model developed by the Instituto de Ingenieria of the Universidad Nacional Autonoma de Mexico. This paper presents the mathematical model and its numerical solution using the Method of Characteristics and the Newton-Raphson Method. With the new modelling system it is possible to evaluate the pressure fluctuation time series due to start up at any pumping system. Using this new system a reliable explanation of bursts at the Rio Yaqui-Guaymas pipeline system could be set forth. [Spanish] Al disenar conducciones a presion, es comun que se presente especial atencion a los transitorios hidraulicos generados por paros de emergencia de los equipos de bombeo. En el acueducto rio Yaqui-Guaymas, Sonora, Mexico, los transitorios generados al poner en marcha los equipos de bombeo son tan importantes como los productos por disparo de bombas. En el Instituto de Ingenieria de la UNAM, se desarrollo e implanto en un programa de simulacion de transitorios hidraulicos en tuberias a presion una subrutina para simular el arranque de equipos de bombeo. El modelo matematico esta formado por el conjunto de ecuaciones dinamica y de continuidad, asi como la condicion de frontera que describe el arranque de las bombas. Se rescriben las ecuaciones dinamicas y de continuidad, con el metodo de las caracteristicas y se plantea un sistema de ecuaciones no lineales, el cual se resuelve con el metodo de Newton-Raphson. La simulacion del arranque de las bombas del acueducto en estudio, arroja valores de las cargas piezom ricas maximas y minimas mayores que la resistencia de la tuberia y menores que la topografia del
Energy Technology Data Exchange (ETDEWEB)
Carmona Paredes, L.G.; Carmona Paredes, R.B. [Instituto de Ingenieria, UNAM, Mexico, D.F. (Mexico)
2000-12-01
Water closed conduits are commonly designed with special attention paid to pressure surges due to pumping failures. In some particular cases, such at the Rio Yaqui-Guaymas water pipeline system, pressure surges due to pumping start ups are as high and dangerous as those produced by pumping failures. New subroutines were thus developed and included in the Closed Conduit Flow Transient Model developed by the Instituto de Ingenieria of the Universidad Nacional Autonoma de Mexico. This paper presents the mathematical model and its numerical solution using the Method of Characteristics and the Newton-Raphson Method. With the new modeling system it is possible to evaluate the pressure fluctuation time series due to start up at any pumping system. Using this new system a reliable explanation of bursts at the Rio Yaqui-Guaymas system could be set forth. [Spanish] Al disenar conducciones a presion, es comun que se preste especial atencion a los transitorios hidraulicos generados por paros de emergencia de los equipos de bombeo. En el acueducto rio Yaqui-Guaymas, Sonora, Mexico, los transitorios generados al poner en marcha los equipos de bombeo son tan importantes como los producidos por disparo de bombas. En el Instituto de Ingenieria de la UNAM, se desarrollo e implanto en su programa de simulacion de transitorios hidraulicos en tuberias a presion una subrutina para simular el arranque de equipos de bombeo. El modelo matematico esta formado por el conjunto de ecuaciones dinamica y de continuidad, asi como la condicion de frontera que describe el arranque de las bombas. Se reescriben las ecuaciones dinamica y de continuidad, con el metodo de las caracteristicas y se plantea un sistema de ecuaciones no lineales, el cual se resuelve con el metodo de las caracteristicas y se plantea un sistema de ecuaciones no lineales, el cual se resuelve con el metodo de newton-raphson. La simulacion del arranque de las bombas del acueducto en estudio, arroja valores de las cargas
The Prediction of Maximum Amplitudes of Solar Cycles and the Maximum Amplitude of Solar Cycle 24
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
We present a brief review of predictions of solar cycle maximum ampli-tude with a lead time of 2 years or more. It is pointed out that a precise predictionof the maximum amplitude with such a lead-time is still an open question despiteprogress made since the 1960s. A method of prediction using statistical character-istics of solar cycles is developed: the solar cycles are divided into two groups, ahigh rising velocity (HRV) group and a low rising velocity (LRV) group, dependingon the rising velocity in the ascending phase for a given duration of the ascendingphase. The amplitude of Solar Cycle 24 can be predicted after the start of thecycle using the formula derived in this paper. Now, about 5 years before the startof the cycle, we can make a preliminary prediction of 83.2-119.4 for its maximumamplitude.
Spurious cross-frequency amplitude-amplitude coupling in nonstationary, nonlinear signals
Yeh, Chien-Hung; Lo, Men-Tzung; Hu, Kun
2016-07-01
Recent studies of brain activities show that cross-frequency coupling (CFC) plays an important role in memory and learning. Many measures have been proposed to investigate the CFC phenomenon, including the correlation between the amplitude envelopes of two brain waves at different frequencies - cross-frequency amplitude-amplitude coupling (AAC). In this short communication, we describe how nonstationary, nonlinear oscillatory signals may produce spurious cross-frequency AAC. Utilizing the empirical mode decomposition, we also propose a new method for assessment of AAC that can potentially reduce the effects of nonlinearity and nonstationarity and, thus, help to avoid the detection of artificial AACs. We compare the performances of this new method and the traditional Fourier-based AAC method. We also discuss the strategies to identify potential spurious AACs.
Directory of Open Access Journals (Sweden)
Sumit Goyal
2013-05-01
Full Text Available This communication reports the latest trends of advertising on social media. Social media advertising means to gain traffic or attention of online users through social media sites. Today, when a user thinks about buying something, he first comes to the internet, searches for that product, compares its price with other competing brands and takes a decision, which one to buy. In this write-up, author has discussed many aspects concerning advertising through social media, viz., what is social media? What is the impact of social media on mainstream media, why to advertise on social media? and what should be the strategy for advertising on social media. The author is of the view that in the year 2013, $4 billion will be spent on social media advertising across the globe and social media industry will generate over 1,00,000 new jobs all around the world.
On the soft limit of tree-level string amplitudes
Bianchi, Massimo
2016-01-01
We study the soft behavior of string scattering amplitudes at three level with massless and massive external insertions, relying on different techniques to compute 4-points amplitudes respectively with open or closed strings.
Automating QCD amplitudes with on-shell methods
Badger, Simon
2016-01-01
We review some of the modern approaches to scattering amplitude computations in QCD and their application to precision LHC phenomenology. We emphasise the usefulness of momentum twistor variables in parameterising general amplitudes.
Topological amplitudes in heterotic superstring theory
International Nuclear Information System (INIS)
We show that certain heterotic string amplitudes are given in terms of correlators of the twisted topological (2,0) SCFT, corresponding to the internal sector of the N = 1 spacetime supersymmetric background. The genus g topological partition function Fg corresponds to a term in the effective action of the form W2g, where W is the gauge or gravitational superfield. We study also recursion relations related to holomorphic anomalies, showing that, contrary to the type II case, they involve correlators of anti-chiral superfields. The corresponding terms in the effective action are of the form W2gIIn, where II is a chiral superfield obtained by chiral projection of a general superfield. We observe that the structure of the recursion relations is that of N = 1 spacetime supersymmetry Ward identity. We give also a solution of the tree level recursion relations and discuss orbifold examples. (author). 23 refs, 2 figs
Topological amplitudes in heterotic superstring theory
International Nuclear Information System (INIS)
We show that certain heterotic string amplitudes are given in terms of correlators of the twisted topological (2,0) SCFT, corresponding to the internal sector of the N=1 space-time supersymmetric background. The genus g topological partition function Fg corresponds to a term in the effective action of the form W2g, where W is the gauge or gravitational superfield. We study also recursion relations related to holomorphic anomalies, showing that, contrary to the type II case, they involve correlators of anti-chiral superfields. The corresponding terms in the effective action are of the form W2gΠn, where Π is a chiral superfield obtained by chiral projection of a general superfield. We observe that the structure of the recursion relations is that of N=1 space-time supersymmetry Ward identity. We give also a solution of the tree-level recursion relations and discuss orbifold examples. (orig.)
Amplitude determinant coupled cluster with pairwise doubles
Zhao, Luning
2016-01-01
Recently developed pair coupled cluster doubles (pCCD) theory successfully reproduces doubly occupied configuration interaction (DOCI) with mean field cost. However, the projective nature of pCCD makes the method non-variational and thus hard to improve systematically. As a variational alternative, we explore the idea of coupled-cluster-like expansions based on amplitude determinants and develop a specific theory similar to pCCD based on determinants of pairwise doubles. The new ansatz admits a variational treatment through Monte Carlo methods while remaining size-consistent and, crucially, polynomial cost. In the dissociations of LiH, HF, H2O and N2, the method performs very similarly to pCCD and DOCI, suggesting that coupled-cluster-like ansatzes and variational evaluation may not be mutually exclusive.
Evaluation of new spin foam vertex amplitudes
International Nuclear Information System (INIS)
The Christensen-Egan algorithm is extended and generalized to efficiently evaluate new spin foam vertex amplitudes proposed by Engle, Pereira and Rovelli and Freidel and Krasnov, with or without (factored) boundary states. A concrete pragmatic proposal is made for comparing the different models using uniform methodologies, applicable to the behavior of large spin asymptotics and of expectation values of specific semiclassical observables. The asymptotics of the new models exhibit non-oscillatory, power-law decay similar to that of the Barrett-Crane model, though with different exponents. Also, an analysis of the semiclassical wave packet propagation problem indicates that the Magliaro, Rovelli and Perini's conjecture of good semiclassical behavior of the new models does not hold for generic factored states, which neglect spin-spin correlations.
Y-system for scattering amplitudes
International Nuclear Information System (INIS)
We compute N=4 super Yang-Mills planar amplitudes at strong coupling by considering minimal surfaces in AdS5 space. The surfaces end on a null polygonal contour at the boundary of AdS. We show how to compute the area of the surfaces as a function of the conformal cross ratios characterizing the polygon at the boundary. We reduce the problem to a simple set of functional equations for the cross ratios as functions of the spectral parameter. These equations have the form of thermodynamic Bethe ansatz (TBA) equations. The area is the free energy of the TBA system. We consider any number of gluons and in any kinematic configuration.
Critical Initial Amplitude of Langmuir Wave Damping
International Nuclear Information System (INIS)
By one-dimensional Vlasov-Poisson simulation, the critical initial state marking the transition between the Landau scenario, in which the electric fields definitively damped to zero and the O'NEIL scenario, in which the Landau damping is stopped after a certain damping stage, is studied. It is found that the critical initial amplitude in* can only exist when the product of the wave number (km) and the electron thermal velocity (vth) is moderate, that is, 0.2 mvth m for a fixed vth, and also increases with the increase in vth for a fixed km. When kmvth is fixed, the value in* also changes with the wave number and the electron thermal velocity, even though the damping rate and the oscillation frequency are the same in this case.
Experimental generation of amplitude squeezed vector beams
Chille, Vanessa; Semmler, Marion; Banzer, Peter; Aiello, Andrea; Leuchs, Gerd; Marquardt, Christoph
2016-01-01
We present an experimental method for the generation of amplitude squeezed high-order vector beams. The light is modified twice by a spatial light modulator such that the vector beam is created by means of a collinear interferometric technique. A major advantage of this approach is that it avoids systematic losses, which are detrimental as they cause decoherence in continuous-variable quantum systems. The utilisation of a spatial light modulator (SLM) gives the flexibility to switch between arbitrary mode orders. The conversion efficiency with our setup is only limited by the efficiency of the SLM. We show the experimental generation of Laguerre-Gauss (LG) modes with radial indices up to 1 and azimuthal indices up to 3 with complex polarization structures and a quantum noise reduction up to -0.9dB$\\pm$0.1dB. The corresponding polarization structures are studied in detail by measuring the spatial distribution of the Stokes parameters.
Nonlinear amplitude dynamics in flagellar beating
Oriola, David; Casademunt, Jaume
2016-01-01
The physical basis of flagellar and ciliary beating is a major problem in biology which is still far from completely understood. The fundamental cytoskeleton structure of cilia and flagella is the axoneme, a cylindrical array of microtubule doublets connected by passive crosslinkers and dynein motor proteins. The complex interplay of these elements leads to the generation of self-organized bending waves. Although many mathematical models have been proposed to understand this process, few attempts have been made to assess the role of dyneins on the nonlinear nature of the axoneme. Here, we investigate the nonlinear dynamics of flagella by considering an axonemal sliding control mechanism for dynein activity. This approach unveils the nonlinear selection of the oscillation amplitudes, which are typically either missed or prescribed in mathematical models. The explicit set of nonlinear equations are derived and solved numerically. Our analysis reveals the spatiotemporal dynamics of dynein populations and flagell...
Rho-0 Meson Helicity Amplitude Ratios at HERMES
Murray, Morgan
2012-01-01
The study of {\\rho}0 meson helicity amplitude ratios at HERMES shows that the amplitude hierarchy expected from pQCD is confirmed. The contribution of Unnatural Parity Exchange in the production of {\\rho}0 mesons is significant at HERMES kinematics and there is a large phase-difference in the leading F11 and F01 amplitudes. The kinematic dependences of the amplitude ratios only sometimes follow theory-based expectations.
Correlations for reduced-width amplitudes in 49V
International Nuclear Information System (INIS)
Measurement of the relative sign of inelastic proton-channel amplitudes permits the determination of amplitude correlations. Data were obtained for 45 5/2+ resonances in 49V. Although the reduced widths in each channel followed a Porter-Thomas distribution, large amplitude correlations were observed. The results are compared with the reduced-width--amplitude distribution of Krieger and Porter. This is the first direct test of the Krieger-Porter distribution
Directory of Open Access Journals (Sweden)
Édisson Ramiro Cepeda Arias
2009-06-01
Full Text Available Se presenta el análisis de las características físicas, químicasy microbiológicas de los lodos producidos bajo un sistemade tratamiento biológico de aguas residuales domésticas,específicamente de lodos activados con aireación extendidapara una planta que trata un flujo de 103 m3/h. Se clasificóel lodo generado en la Planta de Tratamiento de AguasResiduales de Paipa según las concentraciones de metalespesados y patógenos presentes, de acuerdo con lanormatividad internacional vigente, y se analizaron lasdiferentes alternativas de uso o disposición final,soportándose en normas preliminares colombianas yestándares internacionales; se incluye, además, el análisisde la disposición final sin ninguna intención de reciclaje orecuperación, como lo es el relleno sanitario y laincineración, junto con la evaluación de las diferentesalternativas para plantear la solución más viable desde elpunto de vista ambiental, sanitario, económico y social.
Directory of Open Access Journals (Sweden)
MÍRLEY MINDIOLA
2008-01-01
Full Text Available El objetivo del presente trabajo fue evaluar la carga contaminante presente en los efluentes líquidos que se generan durante el proceso de refinación química de oro y de plata con ácido nítrico. Para tal fin se diseñó una herramienta matemática denominada Índice de Carga Contaminante (ICC, que permite valorar de manera cualitativa y cuantitativa la contaminación generada por dichos vertimientos. Para el diseño del ICC se tuvo en cuenta las variables cuantificas en los efluentes, su efecto contaminante diferente, y su nivel de toxicidad y/o peligrosidad. Para el desarrollo de la herramienta se contó con información de campo, obtenida a partir de un muestreo realizado a un grupo representativo de talleres, de este sector industrial de la ciudad de Bucaramanga. Con el cálculo del ICC el grupo de talleres en estudio se ubicó en un rango de calificación de calidad ambiental entre muy mala y pésima, corroborando la hipótesis de que los efluentes generados por este sector industrial necesitan de manera urgente un tratamiento de remediación.
Computations of superstring amplitudes in pure spinor formalism via Cadabra
Suna, Ke-Sheng; Sun, Fei; Zhang, Hai-Bin
2016-01-01
The discovery of pure spinor formalism makes the computation of superstring s- cattering amplitudes possible. In this paper, we will illustrate how computer algebra system Cadabra is used in computing the supersymmetric amplitude in pure spinor formalism and provide the source code that computes the tree-level massless 5-gluon amplitude.
Closed String Amplitudes in Open String Field Theory
Takahashi, Tomohiko; Zeze, Syoji
2003-01-01
We investigate gauge invariant operators corresponding to on-shell closed string states in open string field theory. Using both oscillator representation and conformal mapping techniques, we calculate a two closed string tachyon amplitude that connects two gauge invariant operators by an open string propagator.We find that this amplitude is in a complete agreement with the usual disc amplitude.
Accurate Period Approximation for Any Simple Pendulum Amplitude
Institute of Scientific and Technical Information of China (English)
XUE De-Sheng; ZHOU Zhao; GAO Mei-Zhen
2012-01-01
Accurate approximate analytical formulae of the pendulum period composed of a few elementary functions for any amplitude are constructed.Based on an approximation of the elliptic integral,two new logarithmic formulae for large amplitude close to 180° are obtained.Considering the trigonometric function modulation results from the dependence of relative error on the amplitude,we realize accurate approximation period expressions for any amplitude between 0 and 180°.A relative error less than 0.02％ is achieved for any amplitude.This kind of modulation is also effective for other large-amplitude logarithmic approximation expressions.%Accurate approximate analytical formulae of the pendulum period composed of a few elementary functions for any amplitude are constructed. Based on an approximation of the elliptic integral, two new logarithmic formulae for large amplitude close to 180° are obtained. Considering the trigonometric function modulation results from the dependence of relative error on the amplitude, we realize accurate approximation period expressions for any amplitude between 0 and 180°. A relative error less than 0.02% is achieved for any amplitude. This kind of modulation is also effective for other large-amplitude logarithmic approximation expressions.
MHV Vertices And Tree Amplitudes In Gauge Theory
Cachazo, Freddy; Svrcek, Peter; Witten, Edward
2004-01-01
As an alternative to the usual Feynman graphs, tree amplitudes in Yang-Mills theory can be constructed from tree graphs in which the vertices are tree level MHV scattering amplitudes, continued off shell in a particular fashion. The formalism leads to new and relatively simple formulas for many amplitudes, and can be heuristically derived from twistor space.
... Management Education & Events Advocacy For Patients About ACOG Media and Body Image Home For Patients Search FAQs Media and Body ... and Body Image TFAQ002, June 2016 PDF Format Media and Body Image Especially For Teens How can the media make ...
Locatis, Craig
2007-01-01
Whether media affect learning has been debated for decades. The discussion of media's effectiveness has raised questions about the usefulness of comparison studies, not only in assessing applications of technology but in other areas as well. Arguments that media do not affect learning are re-examined and issues concerning media effects on expert…
Groebel, Jo
1998-01-01
Presents the results of the UNESCO global study on media violence and children which was conducted between 1996 and 1997. Highlights include the role of the media, media heroes as role models, media violence and aggression, differences by gender, rural versus urban environments, the pervasiveness of television, and recommendations. (Author/LRW)
DEFF Research Database (Denmark)
Vestergaard, Vitus; Mortensen, Christian Hviid
2011-01-01
throughout the Internet, most notably on web 2.0 sites like YouTube. The Media Museum has embraced the remix paradigm with the development of an interactive media experience centre called the Media Mixer. Here the museum users can produce, deconstruct, reconstruct and finally publish and share digital media...
Scarratt, Elaine, Ed.; Davison, Jon, Ed.
2011-01-01
"The Media Teacher's Handbook" is an indispensible guide for all teachers, both specialist and non-specialist, delivering Media Studies and media education in secondary schools and colleges. It is the first text to draw together the three key elements of secondary sector teaching in relation to media study--the "theoretical", the "practical" and…
Bejan, A
2006-01-01
Provides an introduction to convection in porous media, such as fibrous insulation, geological strata, and catalytic reactors. This third edition covers ""designed"" porous media, the theory of deformable media, modeling viscous dissipation in hyperporous media, and more. It is useful for researchers, practicing engineers and students.
Phase and amplitude detection system for the Stanford Linear Accelerator
International Nuclear Information System (INIS)
A computer controlled phase and amplitude detection system to measure and stabilize the rf power sources in the Stanford Linear Accelerator is described. This system measures the instantaneous phase and amplitude of a 1 microsecond 2856 MHz rf pulse and will be used for phase feedback control and for amplitude and phase jitter detection. This paper discusses the measurement system performance requirements for the operation of the Stanford Linear Collider, and the design and implementation of the phase and amplitude detection system. The fundamental software algorithms used in the measurement are described, as is the performance of the prototype phase and amplitude detector system
Alexander Fedorov
2011-01-01
The author supposed that media education models can be divided into the following groups:- educational-information models (the study of the theory, history, language of media culture, etc.), based on the cultural, aesthetic, semiotic, socio-cultural theories of media education;- educational-ethical models (the study of moral, religions, philosophical problems relying on the ethic, religious, ideological, ecological, protectionist theories of media education;- pragmatic models (practical media...
Social media influencer marketing
Isosuo, Heli
2016-01-01
The marketing field is changing simultaneously with the digital world. Social media is getting more and more important to marketers, and there is a need to stand out in the social media noise. Social media influencer marketing could be a good alternative to other types of marketing. A need from the consignor and the interest of the author were the motivations for conducting the study. Sääskilahti Consulting has a social media influencer network Somevaikuttajat, which is offering social media ...
Understanding social media logic
José van Dijck; Thomas Poell
2013-01-01
Over the past decade, social media platforms have penetrated deeply into the mechÂanics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions and rules of social interaction. In this article, we examine the intricate dynamic between social media platforms, mass media, users, and social institutions by calling attention to social media lo...
Meulemann, Heiner; Hagenah, Jörg
2009-01-01
"Mass media are defind as media which have their proper program and constitute their own audience. Mass media research, accordingly, deals with the production of programs and the consumption of the audience. For both perspectives, research topics are justified, data sources are introduced, and recommendation for the research infrastructure are given. As for media production, the establishment of a central media content archive is recommended where content analytic time series of public agenci...
Gauge and Gravity Amplitudes from Trees to Loops
DEFF Research Database (Denmark)
Huang, Rijun
This thesis describes two subjects that I mainly work on during my PhD study. They are both about scattering amplitudes, covering gravity and gauge theories, tree and loop level, with or without supersymmetry. The rst subject is Kawai-Lewellen-Tye(KLT) relation in field theory, which mysteriously...... relates Yang-Mills amplitudes to gravity amplitudes. Based on many known works about KLT and super-KLT relations, we provide a complete map between super-gravity amplitudes and super-Yang-Mills amplitudes for any number of supersymmetry that allowed in 4-dimensional theory. We also provide an explanation...... for vanishing identities of Yang-Mills amplitudes as violation of linear symmetry groups based on KLT relation argument. The second subject is integrand reduction of multi-loop amplitude. The recent methods based on computational algebraic geometry make it possible to systematically study multi...
Monodromies and the structure of gauge and gravity amplitudes
Energy Technology Data Exchange (ETDEWEB)
Vanhove, Pierre [IPhT - Institut de Physique Theorique, Orme des Merisiers bat. 774, PC 136, CEA/DSM/IPhT, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex (France); Institut des Hautes Etudes Scientifiques - IHES, Le Bois-Marie 35, route de Chartres 91440 Bures-sur-Yvette (France)
2010-07-01
We show that different color-ordered tree-level amplitudes in gauge theories satisfy monodromy relations. These relations imply the existence of minimal basis of amplitude and provide the numerator factors of the amplitude for a parametrisation of the tree-level amplitude using only cubic vertices. Applications to supergravity amplitudes follow straightforwardly through the KLT-relations. Through the cuts, these tree-level relations give rise to non-trivial identities at loop level. At higher loop this constrains the critical ultraviolet behaviour of the four-graviton amplitude in N=8 supergravity to all order in perturbation. We argue this implies that the four-graviton N=8 amplitudes has a seven-loop logarithmic divergence in four dimensions. (author)
A new polarization amplitude bias reduction method
Vidal, Matias; Leahy, J. P.; Dickinson, C.
2016-09-01
Polarization amplitude estimation is affected by a positive noise bias, particularly important in regions with low signal-to-noise ratio (SNR). We present a new approach to correct for this bias in the case there is additional information about the polarization angle. We develop the `known-angle estimator' that works in the special case when there is an independent and high SNR (≳ 2σ) measurement of the polarization angle. It is derived for the general case where the uncertainties in the Q, U Stokes parameters are not symmetric. This estimator completely corrects for the polarization bias if the polarization angle is perfectly known. In the realistic case, where the angle template has uncertainties, a small residual bias remains, but that is shown to be much smaller that the one left by other classical estimators. We also test our method with more realistic data, using the noise properties of the three lower frequency maps of Wilkinson Microwave Anisotropy Probe. In this case, the known-angle estimator also produces better results than methods that do not include the angle information. This estimator is therefore useful in the case where the polarization angle is expected to be constant over different data sets with different SNR.
A generalized fidelity amplitude for open systems.
Gorin, T; Moreno, H J; Seligman, T H
2016-06-13
We consider a central system which is coupled via dephasing to an open system, i.e. an intermediate system which in turn is coupled to another environment. Considering the intermediate and far environment as one composite system, the coherences in the central system are given in the form of fidelity amplitudes for a certain perturbed echo dynamics in the composite environment. On the basis of the Born-Markov approximation, we derive a master equation for the reduction of that dynamics to the intermediate system alone. In distinction to an earlier paper (Moreno et al 2015 Phys. Rev. A 92, 030104. (doi:10.1103/PhysRevA.92.030104)), where we discussed the stabilizing effect of the far environment on the decoherence in the central system, we focus here on the possibility of using the measurable coherences in the central system for probing the open quantum dynamics in the intermediate system. We illustrate our results for the case of chaotic dynamics in the near environment, where we compare random matrix simulations with our analytical result. PMID:27140969
The pulsed amplitude unit for the SLC
International Nuclear Information System (INIS)
There is a recurring requirement in the SLC for the control of devices such as magnets, phase shifters, and attenuators on a beam-by-beam basis. The Pulsed Amplitude Unit (PAU) is a single width CAMAC module developed for this purpose. It provides digitally programmed analog output voltages on a beam-by-beam basis. Up to 32 preprogrammed values of output voltage are available from the single analog output of the module, and any of these values can be associated with any of the 256 possible SLC beam definitions. A 12-bit Analog-to-Digital Converter (ADC) digitizes an analog input signal at the appropriate beam time and stores it in a buffer memory. This feature is normally used to monitor the response of the device being controlled by the PAU at each beam time. Initial application of the PAU is a part of the system that controls the output of Klystrons in the SLC. The PAU combines several different functions in a single module. In order to accommodate these functions in a single width CAMAC module, field programmed logic is used extensively. Field Programmable Logic Arrays, Programmed Array Logic, and a Field Programmable Logic Sequencer are employed
Open string topological amplitudes and gaugino masses
International Nuclear Information System (INIS)
We discuss the moduli-dependent couplings of the higher derivative F-terms (TrW2)h-1, where W is the gauge N =1 chiral superfield. They are determined by the genus zero topological partition function F(0,h), on a world-sheet with h boundaries. By string duality, these terms are also related to heterotic topological amplitudes studied in the past, with the topological twist applied only in the left-moving supersymmetric sector of the internal N =(2,0) superconformal field theory. The holomorphic anomaly of these couplings relates them to terms of the form Πn(TrW2)h-2, where Π's represent chiral projections of non-holomorphic functions of chiral superfields. An important property of these couplings is that they violate R-symmetry for h ≥ 3. As a result, once supersymmetry is broken by D-term expectation values, (TrW2)2 generates gaugino masses that can be hierarchically smaller than the scalar masses, behaving as m1/2 ∼ m04 in string units. Similarly, ΠTrW2 generates Dirac masses for non-chiral brane fermions, of the same order of magnitude. This mechanism can be used for instance to obtain fermion masses at the TeV scale for scalar masses as high as m0 ∼ O (1013) GeV. We present explicit examples in toroidal string compactifications with intersecting D-branes. (author)
Gearbox Vibration Signal Amplitude and Frequency Modulation
Directory of Open Access Journals (Sweden)
Fakher Chaari
2012-01-01
Full Text Available Gearboxes usually run under fluctuating load conditions during service, however most of papers available in the literature describe models of gearboxes under stationary load conditions. Main task of published papers is fault modeling for their detection. Considering real situation from industry, the assumption of stationarity of load conditions cannot be longer kept. Vibration signals issued from monitoring in maintenance operations differ from mentioned models (due to load non-stationarity and may be difficult to analyze which lead to erroneous diagnosis of the system. The objective of this paper is to study the influence of time varying load conditions on a gearbox dynamic behavior. To investigate this, a simple spur gear system without defects is modeled. It is subjected to a time varying load. The speed-torque characteristic of the driving motor is considered. The load variation induces speed variation, which causes a variation in the gearmesh stiffness period. Computer simulation shows deep amplitude modulations with sidebands that don't differ from those obtained when there is a defective tooth. In order to put in evidence the time varying load effects, Short Time Fourier Transform and then Smoothed Wigner-Ville distribution are used. Results show that the last one is well suited for the studied case.
Energy Technology Data Exchange (ETDEWEB)
Aguilar Benitez de Lugo, M.
1979-07-01
In this work we present several techniques developed for the extraction of the. Transversity amplitudes governing quasi two-body meson baryon reactions with hypercharge exchange. We review the methods used In processes having a pure spin configuration, as well as the more relevant results obtained with data from K{sup p} and Tp interactions at intermediate energies. The predictions of the additive quark model and the ones following from exchange degeneracy and etoxicity are discussed. We present a formalism for amplitude analysis developed for reactions with mixed spin configurations and discuss the methods of parametric estimation of the moduli and phases of.the amplitudes, as well as the various tests employed to check the goodness of the fits. The calculation of the generalized joint density matrices is given and we propose a method based on the generalization of the idea of multipole moments, which allows to investigate the structure of the decay angular correlations and establishes the quality of the fits and the validity of the simplifying assumptions currently used in this type of studies. (Author) 43 refs.
Dynamical response functions in models of vibrated granular media
Nicodemi, Mario
1998-01-01
In recently introduced schematic lattice gas models for vibrated dry granular media, we study the dynamical response of the system to small perturbations of shaking amplitudes and its relations with the characteristic fluctuations. Strong off equilibrium features appear and a generalized version of the fluctuation dissipation theorem is introduced. The relations with thermal glassy systems and the role of Edwards' compactivity are discussed.
Horikis, Theodoros P
2016-01-01
The generation of rogue waves is investigated via a nonlocal nonlinear Schrodinger (NLS) equation. In this system, modulation instability is suppressed and is usually expected that rogue wave formation would also be limited. On the contrary, a parameter regime is identified where the instability is suppressed but nevertheless the number and amplitude of the rogue events increase, as compared to the standard NLS (which is a limit of the nonlocal system). Furthermore, the nature of these waves is investigated; while no analytical solutions are known to model these events, numerically it is shown that they differ significantly from either the rational (Peregrine) or soliton solution of the limiting NLS equation. As such, these findings may also help in rogue wave realization experimentally in these media.
Mass Media: The Invisible Environment.
Glessing, Robert J.; White, William P.
This anthology for students of media consists of essays and articles grouped under four topics: media forms, media content, media environments, and "the last word." Media forms deals with the nature of these kinds of media: electronic, print, film, music, and comics, graffiti, and clothing. Media content contains articles on the news, advertising,…
Amplitude-Nth-power squeezing of PB phase coherent states
Institute of Scientific and Technical Information of China (English)
马志民; 马爱群; 陈国恒; 刘树田; 冯立峰
2004-01-01
PB Phase Coherent States are very important quantum states in quantum optics. In order to investigate the amplitude- Nth -power squeezing of PB Phase Coherent States, we introduce the algebraic properties of the PB phase operator and the PB Phase Coherent States which are constructed by PB phase theory. We applied amplitude- Nth -power squeezing theory to define the Amplitude- Nth -Power Squeezing of PB Phase Coherent States and investigate the characteristic of the amplitude- Nth -power squeezing of PB Phase Coherent States.Phase Coherent State), the results show that when Z is a real number there only exists amplitude- Nth -power squeezing of X component; when Z is a complex number, there exists amplitude- Nth -power squeezing ofX component and Y component; when Z is a pure imaginary number, if N is odd, then there does not exist amplitudeNth -power squeezing of X component, but there exists amplitude- Nth -power squeezing of Ycomponent and ifN is even, then there exists amplitude-Nth -power squeezing of X component, but there does not exist amplitudeNth -power squeezing of Y component.
Amplitude growth due to random, correlated kicks
International Nuclear Information System (INIS)
Historically, stochastic processes, such as gas scattering or stochastic cooling, have been treated by the Fokker-Planck equation. In this approach, usually considered for one dimension only, the equation can be considered as a continuity equation for a variable which would be a constant of the motion in the absence of the stochastic process, for example, the action variable, I = ε/2π for betatron oscillations, where ε is the area of the Courant-Snyder ellipse, or energy in the case of unbunched beams, or the action variable for phase oscillations in case the beam is bunched. A flux, /Phi/, including diffusive terms can be defined, usually to second order. /Phi/ = M1F(I) + M2∂F/∂I + /hor ellipsis/. M1 and M2 are the expectation values of δI and (δI)2 due to the individual stochastic kicks over some period of time, long enough that the variance of these quantities is sufficiently small. Then the Fokker-Planck equation is just ∂F/∂I + ∂/Phi//∂I = 0. In many cases those where the beam distribution has already achieved its final shape, it is sufficient to find the rate of increase of by taking simple averages over the Fokker-Planck equation. At the time this work was begun, there was good knowledge of the second moment for general stochastic processes due to stochastic cooling theory, but the form of the first moment was known only for extremely wideband processes. The purposes of this note are to derive an expression relating the expected single particle amplitude growth to the noise autocorrelation function and to obtain, thereby, the form of M1 for narrow band processes. 4 refs
Scattering amplitudes in four- and six-dimensional gauge theories
International Nuclear Information System (INIS)
We study scattering amplitudes in quantum chromodynamics (QCD), N=4 super Yang-Mills (SYM) theory and the six-dimensional N=(1,1) SYM theory, focusing on the symmetries of and relations between the tree-level scattering amplitudes in these three gauge theories. We derive the tree level and one-loop color decomposition of an arbitrary QCD amplitude into primitive amplitudes. Furthermore, we derive identities spanning the null space among the primitive amplitudes. We prove that every color ordered tree amplitude of massless QCD can be obtained from gluon-gluino amplitudes of N=4 SYM theory. Furthermore, we derive analytical formulae for all gluon-gluino amplitudes relevant for QCD. We compare the numerical efficiency and accuracy of evaluating these closed analytic formulae for color ordered QCD tree amplitudes to a numerically efficient implementation of the Berends-Giele recursion. We derive the symmetries of massive tree amplitudes on the coulomb branch of N=4 SYM theory, which in turn can be obtained from N=(1,1) SYM theory by dimensional reduction. Furthermore, we investigate the tree amplitudes of N=(1, 1) SYM theory and explain how analytical formulae can be obtained from a numerical implementation of the supersymmetric BCFW recursion relation and investigate a potential uplift of the massless tree amplitudes of N=4 SYM theory. Finally we study an alternative to dimensional regularization of N=4 SYM theory. The infrared divergences are regulated by masses obtained from a Higgs mechanism. The corresponding string theory set-up suggests that the amplitudes have an exact dual conformal symmetry. We confirm this expectation and illustrate the calculational advantages of the massive regulator by explicit calculations.
DEFF Research Database (Denmark)
Etter, Michael Andreas; Ravasi, Davide; Colleoni, Elanor
Social media enable millions of users to create and disseminate narratives about organizations that increase their public exposure and shape public perceptions. In this paper, we draw on the sociology of news production and research on computer-mediated communication to discuss how different...... motivational drivers and contextual conditions associated with the formation of narratives in traditional news media and social media influence their content, diffusion, and impact significantly. Our analysis suggests that current theories of media reputation may provide an incomplete representation...... of the phenomenon, and highlight theoretically relevant differences and interrelationships between reputational dynamics involving news media and social media....
Directory of Open Access Journals (Sweden)
Sergio Rosas
2007-01-01
Full Text Available Se presenta el estudio técnico-económico para la obtención de ácido sulfúrico por medio del proceso de contacto doble. Con base en las características de los gases residuales generados por la tostación de piritas se selecciona la tecnología de limpieza del efluente y el proceso de producción de ácido sulfúrico. Para la limpieza de los gases se establece utilizar un tren de separación conformado por un separador ciclónico, un lavador Venturi, un eliminador de neblina y dos precipitadores electrostáticos de neblina ácida. Además, para la síntesis de trióxido de azufre se diseña un convertidor catalítico de cuatro camas. Finalmente, se presentan la estimación de los costos de capital y la factibilidad económica para dos concentraciones de producto.A technical-economical study of the sulphuric acid production by the double-contact process is presented. Based on the characteristics of the residual gases produced by pyrite roasting the effluent cleaning technology and the sulphuric acid production process were selected. To clean out the gaseous effluent a separation train that consists in a cyclone separator, a Venturi washer, a mist eliminator, and two electrostatic precipitators were considered. Also, for the sulphur trioxide synthesis a four-bed catalytic converter was designed. Finally, the capital cost estimation and the economic feasibility for two product concentrations are presented.
Directory of Open Access Journals (Sweden)
Ivanna M. Penna
2008-06-01
Full Text Available En los Andes nor-neuquinos, existe una gran concentración de depósitos de avalanchas de roca que generan endicamientos naturales. El colapso temprano de estos diques generados por deslizamientos de ladera es el proceso evolutivo más probable. Paleocostas, profundas y agudas brechas de colapso, y depósitos de outburst flood permiten reconstruir las características de las lagunas asociadas a los respectivos diques. En esta región, el último evento glaciario ha creado pendientes abruptas y fracturación interna de los materiales, los que determinaron un aumento de la susceptibilidad al colapso de las pendientes por factores externos como sismicidad o precitaciones. La distribución de las avalanchas aparenta estar asociada a la intersección entre fallas con actividad cuaternaria y los valles glaciarios. Este trabajo mostrará actividad neotectónica en el valle del arroyo Pichi- Neuquén, donde se encuentra el retrocorrimiento Aguas Calientes, que presenta estratos de crecimiento cuaternarios en el labio colgante de la falla. Adicionalmente, se observan probables sismitas en la desembocadura del arroyo Colorado. Este trabajo tiene como objetivo comparar el origen, similitud de inductores (probable actividad sísmica y ambiente geomorfológico de las avalanchas Río Barrancas y Navarrete, con énfasis en esta última. El primer dique natural mencionado ha colapsado catastróficamente (debido a un aumento del influjo de agua a la laguna luego de 2,2 Ka de existencia. En el segundo caso, la edad del depósito de avalancha y sus causas de colapso son aún inciertas. La existencia de un flujo de detritos en la margen este de la laguna Navarrete y la similar cota entre la paleocosta y el tope del dique, permiten proponer distintas hipótesis acerca de las causas de colapso del dique.
Characteristics of thermally assisted magnetic recording in granular perpendicular media
International Nuclear Information System (INIS)
The effect of thermally assisted magnetic recording using granular perpendicular media with a single-pole-trimmed head has been investigated. A read/write experiment using a spin stand in which the media were heated by laser irradiation demonstrated that the track average amplitude strongly depends on both the position of the write head relative to the center of the laser spot in the down-track direction and on the laser power. Although the signal-to-noise ratio increased with the coercivity of the media, the increment was small; this is thought to be caused by an increase in the switching field distribution of the media with temperature. Our results suggest that the magnetic constant of the media must be optimized with respect to the temperature of writing in order for high-density thermally assisted magnetic recording to be realized
AMAMM - All Media Are Mixed Media
DEFF Research Database (Denmark)
All Media Are Mixed Media Alle medier er blandingsmedier. Alle kunstarter er kompositte. Alle sanser er sammensatte. Alle medialiteter er miksede og mangfoldige. Alle er AMAMM. Denne påstand står centralt i ord-, billed- og medie-teoretikeren W.J.T. Mitchells forfatterskab. I hosstående bog tager...
Khajeheian, Datis; Roshandel Arbatani, Teher
2011-01-01
The paper investigates evolution of media industry toward the media small and entrepreneur firms, which partly stimulates by global recession. Four questions has been asked:1) What is the effect of recession on media market and on entrepreneurial activities of small media firms and innovators? ,2)What is the strength of media entrepreneurs to rely on it, in emerging media market?, 3)Is focus of media entrepreneurs different from established and large media companies?,4) how media market shoul...
The five-gluon amplitude and one-loop integrals
International Nuclear Information System (INIS)
We review the conventional field theory description of the string motivated technique. This technique is applied to the one-loop five-gluon amplitude. To evaluate the amplitude a general method for computing dimensionally regulated one-loop integrals is outlined including results for one-loop integrals required for the pentagon diagram and beyond. Finally, two five-gluon helicity amplitudes are given
New relations for gauge-theory amplitudes with matter
International Nuclear Information System (INIS)
We extend a recently discovered set of relations for gauge-theory amplitudes to non-gluonic matter. For all MHV amplitudes we find that these can be made to hold for scalar/fermion/quark cases by inclusion of a factor derived via Ward identities. For six- and seven-point amplitudes with non-gluonic matter we explicitly confirm these relations for NMHV helicity configurations.
Unitarity of the Aharonov-Bohm Scattering Amplitudes
Arai, Masato; Minakata, Hisakazu
1996-01-01
We discuss the unitarity relation of the Aharonov-Bohm scattering amplitude with the hope that it distinguishes between the differing treatments which employ different incident waves. We find that the original Aharonov-Bohm scattering amplitude satisfies the unitarity relation under the regularization prescription whose theoretical foundation does not appear to be understood. On the other hand, the amplitude obtained by Ruijsenaars who uses plane wave as incident wave also satisfies the unita...
EW and QCD One-Loop Amplitudes with RECOLA
Actis, Stefano; Denner, Ansgar; Hofer, Lars; Scharf, Andreas; Uccirati, Sandro
2013-01-01
We present the computer code RECOLA for the computation of EW and QCD amplitudes in the Standard Model at next-to-leading order. One-loop amplitudes are represented as linear combinations of tensor integrals whose coefficients are calculated by means of recursive relations similar to Dyson-Schwinger equations. A novel treatment of colour enables us to recursively construct the colour structure of the amplitude efficiently. RECOLA is linked with the library COLLIER for the computation of the t...
EW and QCD One-Loop Amplitudes with RECOLA
Actis, Stefano; Hofer, Lars; Scharf, Andreas; Uccirati, Sandro
2013-01-01
We present the computer code RECOLA for the computation of EW and QCD amplitudes in the Standard Model at next-to-leading order. One-loop amplitudes are represented as linear combinations of tensor integrals whose coefficients are calculated by means of recursive relations similar to Dyson-Schwinger equations. A novel treatment of colour enables us to recursively construct the colour structure of the amplitude efficiently. RECOLA is linked with the library COLLIER for the computation of the tensor integrals.
N >= 4 Supergravity Amplitudes from Gauge Theory at One Loop
Energy Technology Data Exchange (ETDEWEB)
Bern, Z.; /UCLA; Boucher-Veronneau, C.; /SLAC; Johansson, H.; /Saclay
2011-08-19
We expose simple and practical relations between the integrated four- and five-point one-loop amplitudes of N {ge} 4 supergravity and the corresponding (super-)Yang-Mills amplitudes. The link between the amplitudes is simply understood using the recently uncovered duality between color and kinematics that leads to a double-copy structure for gravity. These examples provide additional direct confirmations of the duality and double-copy properties at loop level for a sample of different theories.
Amplitudes and Ultraviolet Behavior of N = 8 Supergravity
Energy Technology Data Exchange (ETDEWEB)
Bern, Zvi; /UCLA; Carrasco, John Joseph; /Stanford U., Phys. Dept.; Dixon, Lance J.; /SLAC /CERN; Johansson, Henrik; /Saclay, SPhT; Roiban, Radu; /Penn State U.
2011-05-20
In this contribution we describe computational tools that permit the evaluation of multi-loop scattering amplitudes in N = 8 supergravity, in terms of amplitudes in N = 4 super-Yang-Mills theory. We also discuss the remarkable ultraviolet behavior of N = 8 supergravity, which follows from these amplitudes, and is as good as that of N = 4 super-Yang-Mills theory through at least four loops.
Laser beam complex amplitude measurement by phase diversity
Védrenne, Nicolas; Mugnier, Laurent M.; Michau, Vincent; Velluet, Marie-Thérèse; Bierent, Rudolph
2014-01-01
The control of the optical quality of a laser beam requires a complex amplitude measurement able to deal with strong modulus variations and potentially highly perturbed wavefronts. The method proposed here consists in an extension of phase diversity to complex amplitude measurements that is effective for highly perturbed beams. Named CAMELOT for Complex Amplitude MEasurement by a Likelihood Optimization Tool, it relies on the acquisition and processing of few images of the beam section taken ...
Topological Field Theory Amplitudes for $A_{N-1}$ Fibration
Iqbal, Amer; Qureshi, Babar A; Shabbir, Khurram; Shehper, Muhammad A
2015-01-01
We study the partition function ${\\cal N}=1$ 5D $U(N)$ gauge theory with $g$ adjoint hypermultiplets and show that for massless adjoint hypermultiplets it is equal to the partition function of a two dimensional topological field on a genus $g$ Riemann surface. We describe the topological field theory by its amplitudes associated with cap, propagator and pair of pants. These basic amplitudes are open topological string amplitudes associated with certain Calabi-Yau threefolds in the presence of Lagrangian branes.
Topological field theory amplitudes for A N-1 fibration
Iqbal, Amer; Khan, Ahsan Z.; Qureshi, Babar A.; Shabbir, Khurram; Shehper, Muhammad A.
2015-12-01
We study the partition function N=1 5D U( N) gauge theory with g adjoint hypermultiplets and show that for massless adjoint hypermultiplets it is equal to the partition function of a two dimensional topological field on a genus g Riemann surface. We describe the topological field theory by its amplitudes associated with cap, propagator and pair of pants. These basic amplitudes are open topological string amplitudes associated with certain Calabi-Yau threefolds in the presence of Lagrangian branes.
Measuring the phase of the scattering amplitude with vortex beams
Ivanov, I. P.
2012-01-01
We show that colliding vortex beams instead of (approximate) plane waves can lead to a direct measurement of how the overall phase of the plane wave scattering amplitude changes with the scattering angle. Since vortex beams are coherent superpositions of plane waves with different momenta, their scattering amplitude receives contributions from plane wave amplitudes with distinct kinematics. These contributions interfere, leading to the measurement of their phase difference. Although interfere...
Amplitudes and Ultraviolet Behavior of N=8 Supergravity
Bern, Zvi; Dixon, Lance; Johansson, Henrik; Roiban, Radu
2011-01-01
In this contribution we describe computational tools that permit the evaluation of multi-loop scattering amplitudes in N=8 supergravity, in terms of amplitudes in N=4 super-Yang-Mills theory. We also discuss the remarkable ultraviolet behavior of N=8 supergravity, which follows from these amplitudes, and is as good as that of N=4 super-Yang-Mills theory through at least four loops.
N >= 4 Supergravity Amplitudes from Gauge Theory at One Loop
Bern, Z; Johansson, H
2011-01-01
We expose simple and practical relations between the integrated four- and five-point one-loop amplitudes of N >= 4 supergravity and the corresponding (super-)Yang-Mills amplitudes. The link between the amplitudes is simply understood using the recently uncovered duality between color and kinematics that leads to a double-copy structure for gravity. These examples provide additional direct confirmations of the duality and double-copy properties at loop level for a sample of different theories.
DEFF Research Database (Denmark)
Agger, Gunhild; Waade, Anne Marit
2011-01-01
Recent developments in the relationship between media and crime are analyzed, taking both fiction and journalism in account......Recent developments in the relationship between media and crime are analyzed, taking both fiction and journalism in account...
Directory of Open Access Journals (Sweden)
Alexander Fedorov
2011-03-01
Full Text Available The author supposed that media education models can be divided into the following groups:- educational-information models (the study of the theory, history, language of media culture, etc., based on the cultural, aesthetic, semiotic, socio-cultural theories of media education;- educational-ethical models (the study of moral, religions, philosophical problems relying on the ethic, religious, ideological, ecological, protectionist theories of media education;- pragmatic models (practical media technology training, based on the uses and gratifications and ‘practical’ theories of media education;- aesthetical models (aimed above all at the development of the artistic taste and enriching the skills of analysis of the best media culture examples. Relies on the aesthetical (art and cultural studies theory; - socio-cultural models (socio-cultural development of a creative personality as to the perception, imagination, visual memory, interpretation analysis, autonomic critical thinking, relying on the cultural studies, semiotic, ethic models of media education.
Rubens, Wilfred
2012-01-01
Rubens, W. (2012, 5 juni). Sociale media als leermiddel. Presentatie over het gebruik van sociale media binnen het onderwijs, verzorgd tijdens een ouderraadbijeenkomst van de Katholieke Scholengemeenschap Etten-Leur, Etten-Leur, Nederland.
On tree amplitudes in gauge theory and gravity
International Nuclear Information System (INIS)
The BCFW recursion relations provide a powerful way to compute tree amplitudes in gauge theories and gravity, but only hold if some amplitudes vanish when two of the momenta are taken to infinity in a particular complex direction. This is a very surprising property, since individual Feynman diagrams all diverge at infinite momentum. In this paper we give a simple physical understanding of amplitudes in this limit, which corresponds to a hard particle with (complex) light-like momentum moving in a soft background, and can be conveniently studied using the background field method exploiting background light-cone gauge. An important role is played by enhanced spin symmetries at infinite momentum-a single copy of a 'Lorentz' group for gauge theory and two copies for gravity-which together with Ward identities give a systematic expansion for amplitudes at large momentum. We use this to study tree amplitudes in a wide variety of theories, and in particular demonstrate that certain pure gauge and gravity amplitudes do vanish at infinity. Thus the BCFW recursion relations can be used to compute completely general gluon and graviton tree amplitudes in any number of dimensions. We briefly comment on the implications of these results for computing massive 4D amplitudes by KK reduction, as well understanding the unexpected cancelations that have recently been found in loop-level gravity amplitudes
Comment on the Identities of the Gluon Tree Amplitudes
Tye, Henry
2010-01-01
Recently, Bjerrum-Bohr, Damgaard, Feng and Sondergaard derived a set of new interesting quadratic identities of the Yang-Mills tree scattering amplitudes. Here we comment that these quadratic identities of YM amplitudes actually follow directly from the KLT relation for graviton-dilaton-axion scattering amplitudes (in 4 dimensional spacetime). This clarifies their physical origin and also provides a simpler version of the new identities. We also comment that the recently discovered Bern-Carrasco-Johansson identities of YM helicity amplitudes can be verified by using (repeatedly) the Schouten identity. We also point out additional quadratic identities that can be written down from the KLT relations.
Monodromy and Kawai-Lewellen-Tye Relations for Gravity Amplitudes
Bjerrum-Bohr, N E J
2010-01-01
We are still learning intriguing new facets of the string theory motivated Kawai-Lewellen-Tye (KLT) relations linking products of amplitudes in Yang-Mills theories and amplitudes in gravity. This is very clearly displayed in computations of N=8 supergravity where the perturbative expansion show a vast number of similarities to that of N=4 super-Yang-Mills. We will here investigate how identities based on monodromy relations for Yang-Mills amplitudes can be very useful for organizing and further streamlining the KLT relations yielding even more compact results for gravity amplitudes.
Tree-level amplitudes in the nonlinear sigma model
Kampf, Karol; Novotný, Jirí; Trnka, Jaroslav
2013-05-01
We study in detail the general structure and further properties of the tree-level amplitudes in the SU( N) nonlinear sigma model. We construct the flavor-ordered Feynman rules for various parameterizations of the SU( N) fields U ( x), write down the Berends-Giele relations for the semi-on-shell currents and discuss their efficiency for the amplitude calculation in comparison with those of renormalizable theories. We also present an explicit form of the partial amplitudes up to ten external particles. It is well known that the standard BCFW recursive relations cannot be used for reconstruction of the the on-shell amplitudes of effective theories like the SU( N) nonlinear sigma model because of the inappropriate behavior of the deformed on-shell amplitudes at infinity. We discuss possible generalization of the BCFW approach introducing "BCFW formula with subtractions" and with help of Berends-Giele relations we prove particular scaling properties of the semi-on-shell amplitudes of the SU( N) nonlinear sigma model under specific shifts of the external momenta. These results allow us to define alternative deformation of the semi-on-shell amplitudes and derive BCFW-like recursion relations. These provide a systematic and effective tool for calculation of Goldstone bosons scattering amplitudes and it also shows the possible applicability of on-shell methods to effective field theories. We also use these BCFW-like relations for the investigation of the Adler zeroes and double soft limit of the semi-on-shell amplitudes.
New Relations for Einstein-Yang-Mills Amplitudes
Stieberger, Stephan
2016-01-01
We obtain new relations between Einstein-Yang-Mills (EYM) amplitudes involving N gauge bosons plus a single graviton and pure Yang-Mills amplitudes involving N gauge bosons plus one additional vector boson inserted in a way typical for a gauge boson of a "spectator" group commuting with the group associated to original N gauge bosons. We show that such EYM amplitudes satisfy U(1) decoupling relations similar to Kleiss-Kuijf relations for Yang-Mills amplitudes. We consider a D-brane embedding of EYM amplitudes in the framework of disk amplitudes involving open and closed strings. A new set of monodromy relations is derived for mixed open-closed amplitudes with one closed string inserted on the disk world-sheet and a number of open strings at the boundary. These relations allow expressing the latter in terms of pure open string amplitudes and, in the field-theory limit, they yield the U(1) decoupling relations for EYM amplitudes.
Amplitude analysis of two-body meson-baryon scattering
International Nuclear Information System (INIS)
Information on high-energy scattering amplitudes is extracted from experimental data for πN and KN elastic and charge-exchange scattering using model independent methods based on isospin symmetry and analyticity. These analyses provide numerical knowledge of the scattering amplitudes and make it possible to answer the questions: which amplitudes are responsible for the different experimental features, which models are able to produce such amplitudes and to which extent are duality, SU(3) and quark model relations consistent with the experimental data
Generalized Grover Search Algorithm for Arbitrary Initial Amplitude Distribution
Biron, D; Biham, E; Grassl, M; Lidar, D A; Biron, David; Biham, Ofer; Biham, Eli; Grassl, Markus; Lidar, Daniel A.
1998-01-01
Grover's algorithm for quantum searching of a database is generalized to deal with arbitrary initial amplitude distributions. First order linear difference equations are found for the time evolution of the amplitudes of the r marked and N-r unmarked states. These equations are solved exactly. An expression for the optimal measurement time T \\sim O(\\sqrt{N/r}) is derived which is shown to depend only on the initial average amplitudes of the marked and unmarked states. A bound on the probability of measuring a marked state is derived, which depends only on the standard deviation of the initial amplitude distributions of the marked or unmarked states.
Phase and amplitude control system for Stanford Linear Accelerator
International Nuclear Information System (INIS)
The computer controlled phase and amplitude detection system measures the instantaneous phase and amplitude of a 1 micro-second 2856 MHz rf pulse at a 180 Hz rate. This will be used for phase feedback control, and also for phase and amplitude jitter measurement. The program, which was originally written by John Fox and Keith Jobe, has been modified to improve the function of the system. The software algorithms used in the measurement are described, as is the performance of the prototype phase and amplitude detector system
Roberts, Donald F; Foehr, Ulla G
2008-01-01
American youth are awash in media. They have television sets in their bedrooms, personal computers in their family rooms, and digital music players and cell phones in their backpacks. They spend more time with media than any single activity other than sleeping, with the average American eight- to eighteen-year-old reporting more than six hours of daily media use. The growing phenomenon of "media multitasking"--using several media concurrently--multiplies that figure to eight and a half hours of media exposure daily. Donald Roberts and Ulla Foehr examine how both media use and media exposure vary with demographic factors such as age, race and ethnicity, and household socioeconomic status, and with psychosocial variables such as academic performance and personal adjustment. They note that media exposure begins early, increases until children begin school, drops off briefly, then climbs again to peak at almost eight hours daily among eleven- and twelve-year-olds. Television and video exposure is particularly high among African American youth. Media exposure is negatively related to indicators of socioeconomic status, but that relationship may be diminishing. Media exposure is positively related to risk-taking behaviors and is negatively related to personal adjustment and school performance. Roberts and Foehr also review evidence pointing to the existence of a digital divide--variations in access to personal computers and allied technologies by socioeconomic status and by race and ethnicity. The authors also examine how the recent emergence of digital media such as personal computers, video game consoles, and portable music players, as well as the media multitasking phenomenon they facilitate, has increased young people's exposure to media messages while leaving media use time largely unchanged. Newer media, they point out, are not displacing older media but are being used in concert with them. The authors note which young people are more or less likely to use several
Bharadwaj, R; A. Patel, S. Chokdeepanich, Ph.D.; G.G. Chase, Ph.D.
2008-01-01
Coalescing filters are widely used throughout industry and improved performance will reduce droplet emissions and operating costs. Experimental observations show orientation of micro fibers in filter media effect the permeability and the separation efficiency of the filter media. In this work two methods are used to align the fibers to alter the filter structure. The results show that axially aligned fiber media improve quality factor on the order of 20% and cutting media on an angle from a t...
Haddon, L.
2013-01-01
This article explores a range of research issues relating to children and mobile media, including the potential growth of children’s screen time, the regulation of children’s use of these media, the challenge of managing increasing media options, effects on children’s perception of time, problems posed for parental surveillance and the domestication of mobile media within peer groups. All of these are viewed in the context of broader societal change, evolving norms of childhood and parenthood...
Managing social media conversations
Tolkki, Annukka
2015-01-01
The purpose of this thesis was to explore how companies can manage (monitor and control) social media conversations. Regardless of the companies’ presence in social media networks, they or their industry are constantly being discussed in social media. Therefore organisations should be present in social media, monitor and participate in conversations, in order to turn them into their benefit. There are software and services available to help in monitoring. Variety of tools and statistic de...
Dennis, Everette E.; Pease, Edward C.
1996-01-01
Throughout history the media has primarily been produced by adults, for adults, about adults. Increasingly, children have become a matter of high priority in the modern media society, and as they have, they have also become the subject of much concern. From debates in Congress about the detrimental effects of movies, comic books, and video games over the last century to efforts to court children as media consumers, there is a clear recognition that the media are not now and probably ne...
DEFF Research Database (Denmark)
This work consists of 12 essays on different aspects of Asian media by Japanese, European, and American scholars, many of whom have themselves been involved in the production of media forms. Working in the fields of anthropology, media and cultural studies, and on the basis of hands-on research......, they have written a book on the social practices and cultural attitudes of people producing, reading, watching and listening to different kinds of media in Japan, China, Taiwan, Indonesia, Vietnam, Singapore and India....
Sumit Goyal
2013-01-01
This communication reports the latest trends of advertising on social media. Social media advertising means to gain traffic or attention of online users through social media sites. Today, when a user thinks about buying something, he first comes to the internet, searches for that product, compares its price with other competing brands and takes a decision, which one to buy. In this write-up, author has discussed many aspects concerning advertising through social media, viz., what is social me...
Jelena Perovic
2015-01-01
Few countries in the world have introduced media education into their curriculums. Montenegro became one of them in 2009, when “media literacy” was introduced as an optional subject for 16 and 17 year old students of Gymnasium high schools. This article presents the findings of the first and only research conducted so far on media education in Montenegro. It is a national case study which examines the potential of media education to change the school culture and accelerate education system re...
Mapping digital media: Netherlands
Waal, de, P.R.; Leurdijk, A.; Nordeman, L.; Poell, T.
2012-01-01
The Mapping Digital Media project examines the global opportunities and risks created by the transition from traditional to digital media. Covering 60 countries, the project examines how these changes affect the core democratic service that any media system should provide: news about political, economic, and social affairs.
J. Piotrowski; H.G.M. Vossen; P.M. Valkenburg
2015-01-01
Decades of research have shown that the relationship between media and childhood is not unidirectional but reciprocal. In this article, both directions of the media-child development relationship are presented. We discuss how child development predisposes children's media use and preferences by revi
Jordan, Amy B.
2008-01-01
Amy Jordan addresses the need to balance the media industry's potentially important contributions to the healthy development of America's children against the consequences of excessive and age-inappropriate media exposure. Much of the philosophical tension regarding how much say the government should have about media content and delivery stems…
van Kruistum, Claudia; Leseman, Paul Pm; de Haan, Mariëtte
2014-01-01
In this article, the concept of "media lifestyles" is adopted in order to develop a comprehensive approach toward youth engagement in communication media. We explore how 503 Dutch eighth grade students with full access to new technology combine a broad range of media by focusing on their engagement
DEFF Research Database (Denmark)
In the western world, a diverse and pluralistic media landscape is deemed essential for democracy. But how universal is media pluralism as a concept underpinning media policies? To what extent do normative approaches, regulatory dimensions and monitoring systems differ throughout the world? Adopt...
ХАДАРЦЕВА Л.С.; ДЗАХОЕВА С.Л.
2015-01-01
This article discusses frequently used business applications for social media, including recruiting, employee engagement and communication, tools for business intelligence, and expanding learning opportunities among employees. Social media are becoming powerful business tools. They are helping employers with everything, beginning from recruitment to communications. These applications turn social media into collaborative tools to improve work and product.
Hauge, Chelsey
2014-01-01
This article addresses how capacity is conceived of and understood in youth media/civic education programming, and how beliefs about agency, development, relationality and youth manifests in the discourses, programmes, and practices of organizations operating youth media programmes. Through attention to a youth media and development programme in…
Fedorov, Alexander
2011-01-01
The author supposed that media education models can be divided into the following groups: (1) educational-information models (the study of the theory, history, language of media culture, etc.), based on the cultural, aesthetic, semiotic, socio-cultural theories of media education; (2) educational-ethical models (the study of moral, religions,…
Djankov, Simeon; McLeish, Caralee; Nenova, Tatiana; Shleifer, Andrei
2001-01-01
The authors examine patterns of media ownership in 97 countries around the world. They find that almost universally the largest media firms are controlled by the government or by private families. Government ownership is more pervasive in broadcasting than in the printed media. Government ownership is generally associated with less press freedom, fewer political and economic rights, inferior ...
Klaver, Franca
This 2-part report summarizes Dutch policy on mass media and reviews the status of cable television in the Netherlands. The first part defines the underlying principles of a national policy on mass media in relation to the press, commercial and educational television broadcasting, radio, cable television, and media research. Parliamentary debate…
Nohl, Arnd-Michael
2007-01-01
Abstract This contribution introduces, from a media education perspective, two concepts which may be useful for further theoretical reflection upon the rich empirical material provided in the other articles of this special issue. The first concept, 'cultures of media practice', refers to habitualized patterns of media practice collectively shared by members of a specific social group. The articles provide m...
Pearson, Jerold
2010-01-01
Most people are aware of the increasing importance of social media to institutional advancement, and many colleges and universities have started investing resources in these media. The next step is to measure the impact of social media on the institution and evaluate the success of one's efforts. Every advancement leader should understand how…
Source-Space Cross-Frequency Amplitude-Amplitude Coupling in Tinnitus
Directory of Open Access Journals (Sweden)
Oliver Zobay
2015-01-01
Full Text Available The thalamocortical dysrhythmia (TCD model has been influential in the development of theoretical explanations for the neurological mechanisms of tinnitus. It asserts that thalamocortical oscillations lock a region in the auditory cortex into an ectopic slow-wave theta rhythm (4–8 Hz. The cortical area surrounding this region is hypothesized to generate abnormal gamma (>30 Hz oscillations (“edge effect” giving rise to the tinnitus percept. Consequently, the model predicts enhanced cross-frequency coherence in a broad range between theta and gamma. In this magnetoencephalography study involving tinnitus and control cohorts, we investigated this prediction. Using beamforming, cross-frequency amplitude-amplitude coupling (AAC was computed within the auditory cortices for frequencies (f1,f2 between 2 and 80 Hz. We find the AAC signal to decompose into two distinct components at low (f1,f230 Hz frequencies, respectively. Studying the correlation of AAC with several key covariates (age, hearing level (HL, tinnitus handicap and duration, and HL at tinnitus frequency, we observe a statistically significant association between age and low-frequency AAC. Contrary to the TCD predictions, however, we do not find any indication of statistical differences in AAC between tinnitus and controls and thus no evidence for the predicted enhancement of cross-frequency coupling in tinnitus.
Schmid, Beat
1997-01-01
Internet as a synonyme of the"new media" not only contains and disseminates information worldwide - like electronic broadcast media - , it is also capable of processing information in an interactive manner, since it is computer-based, i.e., its information objects are virtual machines. Thus, the potential of the new media is urging us to reconsider the notion of media. Since we witness that formal logic is constituting the concept of the computer, we need a new model of"media" to describe, un...
Paparella, Michael M; Schachern, Patricia A; Cureoglu, Sebahattin
2002-01-01
Otitis media occurs along a continuum. For example, otitis media with effusion characterized by fluid pathology can lead to chronic otitis media plus chronic mastoiditis, characterized by the presence of intractable tissue pathology such as cholesteatoma, cholesterol granuloma or granulation tissue. The literature defines chronic otitis media as having a tympanic membrane perforation and otorrhea. Amongst many other sequelae, which can result from the continuum, an important common one is chronic silent otitis media. This overlooked entity which includes pathology beneath an intact tympanic membrane is commonly seen in our human temporal bone laboratory and in patients. The clinical pathological correlates of this important disease are discussed herein. PMID:12021496
Directory of Open Access Journals (Sweden)
R. Bharadwaj
2008-06-01
Full Text Available Coalescing filters are widely used throughout industry and improved performance will reduce droplet emissions and operating costs. Experimental observations show orientation of micro fibers in filter media effect the permeability and the separation efficiency of the filter media. In this work two methods are used to align the fibers to alter the filter structure. The results show that axially aligned fiber media improve quality factor on the order of 20% and cutting media on an angle from a thick layered media can improve performance by about 40%. The results also show the improved performance is not monotonically correlated to the average fiber angle of the medium.
Properties of the scattering amplitude for electron-atom collisions
International Nuclear Information System (INIS)
For the scattering of an electron by an atom finiteness of the amplitude at non threshold energies is proved in the framework of the N-body Schroedinger equation. It is also shown that both the direct and exchange amplitudes have analytic continuations for complex values of incident momentum, with pole or cut singularities on the imaginary axis
Infrared Limit of Gluon Amplitudes at Strong Coupling
Buchbinder, Evgeny I.
2007-01-01
In this note, we propose that the infrared structure of gluon amplitudes at strong coupling can be fully extracted from a local consideration near cusps. This is consistent with field theory and correctly reproduces the infrared divergences of the four-gluon amplitude at strong coupling calculated recently by Alday and Maldacena.
Cross-Symmetric Expansion of $\\pi \\pi$ Amplitude Near Threshold
Bolokhov, A A; Manida, I S; Polyakov, M V; Sherman, S G
1996-01-01
The near-threshold expansion of the $\\pi \\pi$ amplitude is developed using the crossing-covariant independent variables. The independent threshold parameters entering the real part of the amplitude in an explicitly Lorentz-invariant way are free from restrictions of isotopic and crossing symmetries. Parameters of the expansion of the imaginary part are recovered by the perturbative unitarity relations.
Double logarithmic asymptotics of quark amplitudes with flavour exchange
International Nuclear Information System (INIS)
Results on the quark scattering and annihilation amplitudes in the Regge region are presented. The perturbative contribution to those amplitudes in the double logarithmic approximation are calculated. In the calculations a method based on dispersion relations and gauge invariance is used. (M.F.W.)
Correlation signals in resonance fluorescence : interpretation via photon scattering amplitudes
Dalibard, J.; Reynaud, S.
1983-01-01
Resonance fluorescence is treated as a collision process where incident laser photons are scattered by an atom. Correlation signals are extracted from an expansion to the second order of the post collision field state. Photon antibunching effect appears as a quantum interference between all the possible scattering amplitudes. When Rayleigh photons are rejected, some amplitudes vanish, leading to a bunching behaviour.
pi-pi interaction amplitudes with chiral constraints
Kaminski, Robert
2000-01-01
The pi-pi interaction amplitudes have been calculated using a three coupled channel model both with and without constraints imposed by chiral models. Roy's equations have been used to compare the amplitudes and to study the role played by chiral constraints in the pi-pi interaction.
Finite temperature amplitudes and reaction rates in Thermofield dynamics
Rakhimov, A M
2001-01-01
We propose a method for calculating the reaction rates and transition amplitudes of generic process taking place in a many body system in equilibrium. The relationship of the scattering and decay amplitudes as calculated in Thermo Field Dynamics the conventional techniques is established. It is shown that in many cases the calculations are relatively easy in TFD.
Amplitude and time characteristics of photomultiplier after pulses
International Nuclear Information System (INIS)
Amplitude-time distributions of KhP2020Q, FEU-87, FEU-30 photomultiplier after pulses within 20 ns-1.4 mcs range were studied by means of self-correlation technique. After pulses caused by ion feedback were identified. Dependences of intensity of after pulses on voltage in photomultipliers and on amplitude of the main pulse at photomultiplier output were determined
Four-Point Amplitude from Open Superstring Field Theory
Berkovits, N; Berkovits, Nathan; Echevarria, Carlos Tello
2000-01-01
An open superstring field theory action has been proposed which does not suffer from contact term divergences. In this paper, we compute the on-shell four-point tree amplitude from this action using the Giddings map. After including contributions from the quartic term in the action, the resulting amplitude agrees with the first-quantized prescription.
Gauge Theory Amplitudes In Twistor Space And Holomorphic Anomaly
Cachazo, Freddy; Svrcek, Peter; Witten, Edward
2004-01-01
We show that, in analyzing differential equations obeyed by one-loop gauge theory amplitudes, one must take into account a certain holomorphic anomaly. When this is done, the results are consistent with the simplest twistor-space picture of the available one-loop amplitudes.
Redatuming Operators Analysis in Homogeneous Media
Oliveira, Fransisco de Souza; Figueiredo, Jose J. S. de; Freitas, Lucas
2015-04-01
A redatuming operation is used to simulate the acquisition of data in new levels, avoiding distortions produced by near-surface irregularities related to either geometric or material property heterogeneities. In this work, the application of the true-amplitude Kirchhoff redatuming (TAKR) operator on homogeneous media is compared with conventional Kirchhoff redatuming (KR) operator restricted to the zero-offset case. The TAKR and the KR operators are analytically and numerically compared in order to verify their impacts on the data at a new level. Analyses of amplitude and velocity sensitivity of the TAKR and KR were performed: one concerning the difference between the weight functions and the other related to the velocity variation. The comparisons between operators were performed using numerical examples. The feasibility of the KR and TAKR operators was demonstrated not only kinematically but also dynamically for their purposes. In other words, one preserves amplitude (KR), and the other corrects the amplitude (TAKR). In the end, we applied the operators to a GPR data set.
Comprehension of digital media
International Nuclear Information System (INIS)
This book is divided four parts. The first part describes media and mark on sign and media, what is the sign?, interpretation of sign and semiotics. The second part is for production sign theory and origin of digital revolution such as the problem of origin of digital revolution, homogeneity of producing goods and sign : triple triangle model for production sign theory, triple triangle model for producing goods, triple triangle model of producing sign and triple triangle model of art works. The third parts deals with development of the media and meaning of digital revolution with four changes : invention of letter, appearance of printed media and establishment modernity, appearance electronic media and mess media and appearance of digital media. The last part mentions ontology of world wide web.
Discontinuities of BFKL amplitudes and the BDS ansatz
Fadin, V. S.; Fiore, R.
2015-12-01
We perform an examination of discontinuities of multiple production amplitudes, which are required for further development of the BFKL approach. It turns out that the discontinuities of 2 → 2 + n amplitudes obtained in the BFKL approach contradict to the BDS ansatz for amplitudes with maximal helicity violation in N = 4 supersymmetric Yang-Mills theory with large number of colors starting with n = 2. Explicit expressions for the discontinuities of the 2 → 3 and 2 → 4 amplitudes in the invariant mass of pairs of produced gluons are obtained in the planar N = 4 SYM in the next-to-leading logarithmic approximation. These expressions can be used for checking the conjectured duality between the light-like Wilson loops and the MHV amplitudes.
Simplicity in the structure of QED and gravity amplitudes
International Nuclear Information System (INIS)
We investigate generic properties of one-loop amplitudes in unordered gauge theories in four dimensions. For such theories the organisation of amplitudes in manifestly crossing symmetric expressions poses restrictions on their structure and results in remarkable cancellations. We show that one-loop multi-photon amplitudes in QED with at least eight external photons are given only by scalar box integral functions. This QED 'no-triangle' property is true for all helicity configurations and has similarities to the 'notriangle' property found in the case of maximal N=8 supergravity. Results are derived both via a world-line formalism as well as using on-shell unitarity methods. We show that the simple structure of the loop amplitude originates from the extremely good BCFW scaling behaviour of the QED tree-amplitude. (orig.)
Amplitudes of stochastically excited oscillations in main-sequence stars
Houdek, G; Christensen-Dalsgaard, J; Gough, D O
1999-01-01
We present estimates of the amplitudes of intrinsically stable stochastically excited radial oscillations in stars near the main sequence. The amplitudes are determined by the balance between acoustical energy generation by turbulent convection (the Lighthill mechanism) and linear damping. Convection is treated with a time-dependent, nonlocal, mixing-length model, which includes both convective heat flux and turbulent pressure in both the equilibrium model and the pulsations. Velocity and luminosity amplitudes are computed for stars with masses between 0.9 M_\\sun and 2.0 M_\\sun in the vicinity of the main sequence, for various metallicities and convection parameters. As in previous studies, the amplitudes are found to increase with stellar mass, and therefore with luminosity. Amongst those stars that are pulsationally stable, the largest amplitudes are predicted for a 1.6 M_\\sun model of spectral type F2; the values are approximately 15 times larger than those measured in the Sun.
New Formulas for Amplitudes from Higher-Dimensional Operators
He, Song
2016-01-01
In this paper we study tree-level amplitudes from higher-dimensional operators, including $F^3$ operator of gauge theory, and $R^2$, $R^3$ operators of gravity, in the Cachazo-He-Yuan formulation. As a generalization of the reduced Pfaffian in Yang-Mills theory, we find a new, gauge-invariant object that leads to gluon amplitudes with a single insertion of $F^3$, and gravity amplitudes by Kawai-Lewellen-Tye relations. When reduced to four dimensions for given helicities, the new object vanishes for any solution of scattering equations on which the reduced Pfaffian is non-vanishing. This intriguing behavior in four dimensions explains the vanishing of graviton helicity amplitudes produced by the Gauss-Bonnet $R^2$ term, and provides a scattering-equation origin of the decomposition into self-dual and anti-self-dual parts for $F^3$ and $R^3$ amplitudes.
New amplitude equation of single-mode laser
Institute of Scientific and Technical Information of China (English)
张莉; 曹力; 吴大进
2003-01-01
The white-gain model and the white-loss model of a single-mode laser are investigated in the presence of crosscorrelations between the real and imaginary parts of quantum noise as well as pump noise. It was found that, like the white cubic model (2001 Chin. Phys. Lett. 18 370), the amplitude equations are all decoupled from the phase equations for the two models, and the same novel term appears in the amplitude equations of the two models. So we can put the amplitude equations of all the models into a general form, that is, the new amplitude equation. We further use this new amplitude equation to study specifically the stationary properties of the laser intensity for the white-gain model.
High Frequency Amplitude Detector for GMI Magnetic Sensors
Directory of Open Access Journals (Sweden)
Aktham Asfour
2014-12-01
Full Text Available A new concept of a high-frequency amplitude detector and demodulator for Giant-Magneto-Impedance (GMI sensors is presented. This concept combines a half wave rectifier, with outstanding capabilities and high speed, and a feedback approach that ensures the amplitude detection with easily adjustable gain. The developed detector is capable of measuring high-frequency and very low amplitude signals without the use of diode-based active rectifiers or analog multipliers. The performances of this detector are addressed throughout the paper. The full circuitry of the design is given, together with a comprehensive theoretical study of the concept and experimental validation. The detector has been used for the amplitude measurement of both single frequency and pulsed signals and for the demodulation of amplitude-modulated signals. It has also been successfully integrated in a GMI sensor prototype. Magnetic field and electrical current measurements in open- and closed-loop of this sensor have also been conducted.
Renormalization of massless Feynman amplitudes in configuration space
Nikolov, Nikolay M.; Stora, Raymond; Todorov, Ivan
2014-05-01
A systematic study of recursive renormalization of Feynman amplitudes is carried out both in Euclidean and in Minkowski configuration spaces. For a massless quantum field theory (QFT), we use the technique of extending associate homogeneous distributions to complete the renormalization recursion. A homogeneous (Poincaré covariant) amplitude is said to be convergent if it admits a (unique covariant) extension as a homogeneous distribution. For any amplitude without subdivergences — i.e. for a Feynman distribution that is homogeneous off the full (small) diagonal — we define a renormalization invariant residue. Its vanishing is a necessary and sufficient condition for the convergence of such an amplitude. It extends to arbitrary — not necessarily primitively divergent — Feynman amplitudes. This notion of convergence is finer than the usual power counting criterion and includes cancellation of divergences.
Renormalization of Massless Feynman Amplitudes in Configuration Space
Nikolov, Nikolay M; Todorov, Ivan
2014-01-01
A systematic study of recursive renormalization of Feynman amplitudes is carried out both in Euclidean and in Minkowski configuration space. For a massless quantum field theory (QFT) we use the technique of extending associate homogeneous distributions to complete the renormalization recursion. A homogeneous (Poincare covariant) amplitude is said to be convergent if it admits a (unique covariant) extension as a homogeneous distribution. For any amplitude without subdivergences - i.e. for a Feynman distribution that is homogeneous off the full (small) diagonal - we define a renormalization invariant residue. Its vanishing is a necessary and sufficient condition for the convergence of such an amplitude. It extends to arbitrary - not necessarily primitively divergent - Feynman amplitudes. This notion of convergence is finer than the usual power counting criterion and includes cancellation of divergences.
Simplicity in the structure of QED and gravity amplitudes
Badger, Simon; Bjerrum-Bohr, N. E. J.; Vanhove, Pierre
2009-02-01
We investigate generic properties of one-loop amplitudes in unordered gauge theories in four dimensions. For such theories the organisation of amplitudes in manifestly crossing symmetric expressions poses restrictions on their structure and results in remarkable cancellations. We show that one-loop multi-photon amplitudes in QED with at least eight external photons are given only by scalar box integral functions. This QED `no-triangle' property is true for all helicity configurations and has similarities to the `no-triangle' property found in the case of maximal Script N = 8 supergravity. Results are derived both via a world-line formalism as well as using on-shell unitarity methods. We show that the simple structure of the loop amplitude originates from the extremely good BCFW scaling behaviour of the QED tree-amplitude.
Effective Field Theories from Soft Limits of Scattering Amplitudes.
Cheung, Clifford; Kampf, Karol; Novotny, Jiri; Trnka, Jaroslav
2015-06-01
We derive scalar effective field theories-Lagrangians, symmetries, and all-from on-shell scattering amplitudes constructed purely from Lorentz invariance, factorization, a fixed power counting order in derivatives, and a fixed order at which amplitudes vanish in the soft limit. These constraints leave free parameters in the amplitude which are the coupling constants of well-known theories: Nambu-Goldstone bosons, Dirac-Born-Infeld scalars, and Galilean internal shift symmetries. Moreover, soft limits imply conditions on the Noether current which can then be inverted to derive Lagrangians for each theory. We propose a natural classification of all scalar effective field theories according to two numbers which encode the derivative power counting and soft behavior of the corresponding amplitudes. In those cases where there is no consistent amplitude, the corresponding theory does not exist. PMID:26196613
Phase space spinor amplitudes for spin 1/2 systems
Watson, P
2010-01-01
The concept of phase space amplitudes for systems with continuous degrees of freedom is generalized to finite-dimensional spin systems. Complex amplitudes are obtained on both a sphere and a finite lattice, in each case enabling a more fundamental description of pure spin states than that previously given by Wigner functions on either the sphere or lattice. In each case the Wigner function can be expressed as the star product of the amplitude and its conjugate, so providing a generalized Born interpretation of amplitudes that emphasizes their more fundamental status. The case of spin-$\\half$ is treated in detail, and it is shown that the phase space amplitudes transform correctly as spinors under under rotations, on both the sphere and the lattice.
Simplicity in the Structure of QED and Gravity Amplitudes
Badger, Simon; Vanhove, Pierre
2009-01-01
We investigate generic properties of one-loop amplitudes in unordered gauge theories in four dimensions. For such theories the organisation of amplitudes in manifestly crossing symmetric expressions poses restrictions on their structure and results in remarkable cancellations. We show that one-loop multi-photon amplitudes in QED with at least eight external photons are given only by scalar box integral functions. This QED `no-triangle' property is true for all helicity configurations and has similarities to the `no-triangle' property found in the case of maximal N = 8 supergravity. Results are derived both via a world-line formalism as well as using on-shell unitarity methods. We show that the simple structure of the loop amplitude originates from the extremely good BCFW scaling behaviour of the QED tree-amplitude.
Understanding Social Media Logic
Directory of Open Access Journals (Sweden)
José van Dijck
2013-08-01
Full Text Available Over the past decade, social media platforms have penetrated deeply into the mechanics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions and rules of social interaction. In this article, we examine the intricate dynamic between social media platforms, mass media, users, and social institutions by calling attention to social media logic—the norms, strategies, mechanisms, and economies—underpinning its dynamics. This logic will be considered in light of what has been identified as mass media logic, which has helped spread the media's powerful discourse outside its institutional boundaries. Theorizing social media logic, we identify four grounding principles—programmability, popularity, connectivity, and datafication—and argue that these principles become increasingly entangled with mass media logic. The logic of social media, rooted in these grounding principles and strategies, is gradually invading all areas of public life. Besides print news and broadcasting, it also affects law and order, social activism, politics, and so forth. Therefore, its sustaining logic and widespread dissemination deserve to be scrutinized in detail in order to better understand its impact in various domains. Concentrating on the tactics and strategies at work in social media logic, we reassess the constellation of power relationships in which social practices unfold, raising questions such as: How does social media logic modify or enhance existing mass media logic? And how is this new media logic exported beyond the boundaries of (social or mass media proper? The underlying principles, tactics, and strategies may be relatively simple to identify, but it is much harder to map the complex connections between platforms that distribute this logic: users that employ them, technologies that
Culture et medias (Culture and the Media).
Abastado, Claude
1982-01-01
The traditional conception of pluralistic culture is contrasted with a new, separate form of culture: mass media culture. Its components are noted: medium, message, "mosaic," and strategy, and methodology for its study is discussed. (MSE)
Achieving seventh-order amplitude accuracy in leapfrog integrations
Williams, Paul
2015-04-01
The leapfrog time-stepping scheme is commonly used in general circulation models of weather and climate. The Robert-Asselin filter is used in conjunction with it, to damp the computational mode. Although the leapfrog scheme makes no amplitude errors when integrating linear oscillations, the Robert-Asselin filter introduces first-order amplitude errors. The RAW filter, which was recently proposed as an improvement, eliminates the first-order amplitude errors and yields third-order amplitude accuracy. This development has been shown to significantly increase the skill of medium-range weather forecasts. However, it has not previously been shown how to further improve the accuracy by eliminating the third- and higher-order amplitude errors. This presentation will show that leapfrogging over a suitably weighted blend of the filtered and unfiltered tendencies eliminates the third-order amplitude errors and yields fifth-order amplitude accuracy. It will also show that the use of a more discriminating (1,-4,6,-4,1) filter instead of a (1,-2,1) filter eliminates the fifth-order amplitude errors and yields seventh-order amplitude accuracy. Other related schemes are obtained by varying the values of the filter parameters, and it is found that several combinations offer an appealing compromise of stability and accuracy. The proposed new schemes are shown to yield substantial forecast improvements in a medium-complexity atmospheric general circulation model. They appear to be attractive alternatives to the filtered leapfrog schemes currently used in many weather and climate models. Reference Williams PD (2013) Achieving seventh-order amplitude accuracy in leapfrog integrations. Monthly Weather Review 141(9), pp 3037-3051. DOI: 10.1175/MWR-D-12-00303.1
Signal amplitude and shape of detector amplitude spectrum at incomplete charge transfer
International Nuclear Information System (INIS)
Operation of a detector under potent capture of charge carriers via localization was studied. Analysis was carried out as applied to semi-insulating gallium arsenide base detectors (SI GaAs) at recording of short-range ions. It was assumed that the main capture of carriers occurred when they were drifting. It was shown that the derived express-ions for a signal amplitude and spectrum shape contained three independent parameters. Determination of their values in the course of the experiment enabled to determine the value of the filed average stress and the rate of its propagation within the structure in the function of the applied stress, as well as, the value of life time of carriers before capture
Verrier, N; Alloul, L; Gross, M
2015-02-01
Sideband holography can be used to get field images (E0 and E1) of a vibrating object for both the carrier (E0) and the sideband (E1) frequency with respect to vibration. Here we propose to record E0 and E1 sequentially and to image the product E1E0* or the correlation 〈E1E0*〉. We show that these quantities are insensitive to the phase related to the object roughness and directly reflect the phase of the mechanical motion. The signal to noise can be improved by averaging E1E0* over a neighbor pixel, yielding 〈E1E0*〉. Experimental validation is made with a vibrating cube of wood and a clarinet reed. At 2 kHz, vibrations of amplitude down to 0.01 nm are detected. PMID:25680060
Verrier, N; Gross, M
2015-01-01
Sideband holography can be used to get fields images (E0 and E1) of a vibrating object for both the carrier (E0) and the sideband (E1) frequency with respect to vibration. We propose here to record E0 and E1 sequentially, and to image the correlation E1E * 0 . We show that this correlation is insensitive the phase related to the object roughness and directly reflect the phase of the mechanical motion. The signal to noise can be improved by averaging the correlation over neighbor pixel. Experimental validation is made with vibrating cube of wood and with a clarinet reed. At 2 kHz, vibrations of amplitude down to 0.01 nm are detected.
International Nuclear Information System (INIS)
The cores of nuclear reactors, including its structural parts and cooling fluids, are complex mechanical systems able to vibrate in a set of normal modes and frequencies, if suitable perturbed. The cyclic variations in the strain state of the core materials may produce changes in density. Changes in density modify the reactivity. Changes in reactivity modify thermal power. Modifications in thermal power produce variations in temperature fields. Variations in temperature produce variations in strain due to thermal-elastic effects. If the variation of the temperature field is fast enough and if the Doppler Effect and other stabilizing prompt effects in the fuel are weak enough, a fast oscillatory instability could be produced, coupled with mechanical vibrations of small amplitude. A recently constructed, simple mathematical model of nuclear reactor kinetics, that improves the one due to A.S. Thompson, is reviewed. It was constructed in order to study, in a first approximation, the stability of the reactor: a nonlinear nuclear-thermal oscillator (that corresponds to reactor point kinetics with thermal-elastic feedback and with frozen delayed neutron effects) is coupled nonlinearly with a linear mechanical-thermal oscillator (that corresponds to the first normal mode of mechanical vibrations excited by thermo-elastic effects). This mathematical model is studied here from the standpoint of mechanical vibrations. It is shown how, under certain conditions, a suitable mechanical perturbation could elicit fast and growing oscillatory instabilities in the reactor power. Applying the asymptotic method due to Krylov, Bogoliubov and Mitropolsky, analytical formulae that may be used in the calculation of the time varying amplitude and phase of the mechanical oscillations are given, as functions of the mechanical, thermal and nuclear parameters of the reactor. The consequences for the mechanical integrity of the reactor are assessed. Some conditions, mainly, but not exclusively
Media relations after the introduction of social media
Mesila, Helin
2010-01-01
In the light of the popularity of social media on one hand, and the contradictive relationships between journalists and public relations practitioners on the other hand, the thesis studies media relations after the introduction of social media. The study focuses on media relations in Estonian public relations scenery. The research answers to the questions: - What are media relations today? - What are the functions of social media and media relations in organizational communication? ...
CLASSICAL MEDIA RELATIONS AND NEW MEDIA RELATIONS IN SPORT
Alexandru Lucian MIHAI
2014-01-01
Media relations in sport mean maintenance of networks and positive relationships with people in the media to obtain positive media exposure for a sport product (informal and formal information sessions with media representatives). Because of the pervasive influence the media has on marketing success, sport marketers must make concerted efforts to create a positive relationship between their sport event and the media. They may accomplish this by providing the media with press releases, having ...
International Nuclear Information System (INIS)
Classical transport of neutral particles in a binary, scattering, stochastic media is discussed. It is assumed that the cross-sections of the constituent materials and their volume fractions are known. The inner structure of the media is stochastic, but there exist a statistical knowledge about the lump sizes, shapes and arrangement. The transmission through the composite media depends on the specific heterogeneous realization of the media. The current research focuses on the averaged transmission through an ensemble of realizations, frm which an effective cross-section for the media can be derived. The problem of one dimensional transport in stochastic media has been studied extensively [1]. In the one dimensional description of the problem, particles are transported along a line populated with alternating material segments of random lengths. The current work discusses transport in two-dimensional stochastic media. The phenomenon that is unique to the multi-dimensional description of the problem is obstacle bypassing. Obstacle bypassing tends to reduce the opacity of the media, thereby reducing its effective cross-section. The importance of this phenomenon depends on the manner in which the obstacles are arranged in the media. Results of transport simulations in multi-dimensional stochastic media are presented. Effective cross-sections derived from the simulations are compared against those obtained for the one-dimensional problem, and against those obtained from effective multi-dimensional models, which are partially based on a Markovian assumption
Notes on High Energy Bosonic Closed String Scattering Amplitudes
Chan, C T; Yang, Y; Chan, Chuan-Tsung; Lee, Jen-Chi; Yang, Yi
2006-01-01
We study bosonic closed string scattering amplitudes in the high-energy limit. We find that the methods of decoupling of high-energy zero-norm states and the high-energy Virasoro constraints, which were adopted in the previous works to calculate the ratios among high-energy open string scattering amplitudes of different string states, persist for the case of closed string. However, we clarify the previous saddle-point calculation for high-energy open string scattering amplitudes and claim that only (t,u) channel of the amplitudes is suitable for saddle-point calculation. By using the relation of closed and open string scattering amplitudes of Kawai, Lewellen and Tye (KLT), we calculate the high-energy closed string scattering amplitudes for arbitrary mass levels. For the case of high-energy closed string four-tachyon amplitude, our result differs from the previous one of Gross and Mende, which is NOT consistent with KLT formula, by an oscillating factor.
Bootstrapping Multi-Parton Loop Amplitudes in QCD
Energy Technology Data Exchange (ETDEWEB)
Bern, Zvi; /UCLA; Dixon, Lance J.; /SLAC; Kosower, David A.; /Saclay, SPhT
2005-07-06
The authors present a new method for computing complete one-loop amplitudes, including their rational parts, in non-supersymmetric gauge theory. This method merges the unitarity method with on-shell recursion relations. It systematizes a unitarity-factorization bootstrap approach previously applied by the authors to the one-loop amplitudes required for next-to-leading order QCD corrections to the processes e{sup +}e{sup -} {yields} Z, {gamma}* {yields} 4 jets and pp {yields} W + 2 jets. We illustrate the method by reproducing the one-loop color-ordered five-gluon helicity amplitudes in QCD that interfere with the tree amplitude, namely A{sub 5;1}(1{sup -}, 2{sup -}, 3{sup +}, 4{sup +}, 5{sup +}) and A{sub 5;1}(1{sup -}, 2{sup +}, 3{sup -}, 4{sup +}, 5{sup +}). Then we describe the construction of the six- and seven-gluon amplitudes with two adjacent negative-helicity gluons, A{sub 6;1}(1{sup -}, 2{sup -}, 3{sup +}, 4{sup +}, 5{sup +}, 6{sup +}) and A{sub 7;1}(1{sup -}, 2{sup -}, 3{sup +}, 4{sup +}, 5{sup +}, 6{sup +}, 7{sup +}), which uses the previously-computed logarithmic parts of the amplitudes as input. They present a compact expression for the six-gluon amplitude. No loop integrals are required to obtain the rational parts.
Scattering Amplitudes and BCFW Recursion in Twistor Space
Mason, L
2009-01-01
A number of recent advances in our understanding of scattering amplitudes have been inspired by ideas from twistor theory. While there has been much work studying the twistor space support of scattering amplitudes, this has largely been done by examining the amplitudes in momentum space. In this paper, we construct the actual twistor scattering amplitudes themselves. The main reasons for doing so are to seek a formulation of scattering amplitudes in N=4 super Yang-Mills in which superconformal symmetry is manifest, and to use the progress in on-shell methods in momentum space to build our understanding of how to construct quantum field theory in twistor space. We show that the recursion relations of Britto, Cachazo, Feng and Witten have a natural twistor formulation that, together with the three-point seed amplitudes, allow us in principle to recursively construct general tree amplitudes in twistor space. The twistor space BCFW recursion is tractable, and we obtain explicit formulae for n-particle MHV and NMH...
Broadband metasurface holograms: toward complete phase and amplitude engineering.
Wang, Qiu; Zhang, Xueqian; Xu, Yuehong; Gu, Jianqiang; Li, Yanfeng; Tian, Zhen; Singh, Ranjan; Zhang, Shuang; Han, Jiaguang; Zhang, Weili
2016-01-01
As a revolutionary three-dimensional imaging technique, holography has attracted wide attention for its ability to photographically record a light field. However, traditional phase-only or amplitude-only modulation holograms have limited image quality and resolution to reappear both amplitude and phase information required of the objects. Recent advances in metasurfaces have shown tremendous opportunities for using a planar design of artificial meta-atoms to shape the wave front of light by optimal control of both its phase and amplitude. Inspired by the concept of designer metasurfaces, we demonstrate a novel amplitude-phase modulation hologram with simultaneous five-level amplitude modulation and eight-level phase modulation. Such a design approach seeks to turn the perceived disadvantages of the traditional phase or amplitude holograms, and thus enable enhanced performance in resolution, homogeneity of amplitude distribution, precision, and signal-to-noise ratio. In particular, the unique holographic approach exhibits broadband characteristics. The method introduced here delivers more degrees of freedom, and allows for encoding highly complex information into designer metasurfaces, thus having the potential to drive next-generation technological breakthroughs in holography. PMID:27615519
Discriminating Simulated Vocal Tremor Source Using Amplitude Modulation Spectra
Carbonell, Kathy M.; Lester, Rosemary A.; Story, Brad H.; Lotto, Andrew J.
2014-01-01
Objectives/Hypothesis Sources of vocal tremor are difficult to categorize perceptually and acoustically. This paper describes a preliminary attempt to discriminate vocal tremor sources through the use of spectral measures of the amplitude envelope. The hypothesis is that different vocal tremor sources are associated with distinct patterns of acoustic amplitude modulations. Study Design Statistical categorization methods (discriminant function analysis) were used to discriminate signals from simulated vocal tremor with different sources using only acoustic measures derived from the amplitude envelopes. Methods Simulations of vocal tremor were created by modulating parameters of a vocal fold model corresponding to oscillations of respiratory driving pressure (respiratory tremor), degree of vocal fold adduction (adductory tremor) and fundamental frequency of vocal fold vibration (F0 tremor). The acoustic measures were based on spectral analyses of the amplitude envelope computed across the entire signal and within select frequency bands. Results The signals could be categorized (with accuracy well above chance) in terms of the simulated tremor source using only measures of the amplitude envelope spectrum even when multiple sources of tremor were included. Conclusions These results supply initial support for an amplitude-envelope based approach to identify the source of vocal tremor and provide further evidence for the rich information about talker characteristics present in the temporal structure of the amplitude envelope. PMID:25532813
Color-factor symmetry and BCJ relations for QCD amplitudes
Brown, Robert W
2016-01-01
Tree-level $n$-point gauge-theory amplitudes with $n-2k$ gluons and $k$ pairs of (massless or massive) particles in the fundamental (or other) representation of the gauge group are invariant under a set of symmetries that act as momentum-dependent shifts on the color factors in the cubic decomposition of the amplitude. These symmetries lead to gauge-invariant constraints on the kinematic numerators. They also directly imply the BCJ relations among the Melia-basis primitive amplitudes previously obtained by Johansson and Ochirov.
Symmetry limit properties of decay amplitudes with mirror matter admixtures
Sánchez-Colón, G; Sanchez-Colon, Gabriel; Garcia, Augusto
2006-01-01
We extend our previous analysis on the symmetry limit properties of non-leptonic and weak radiative decay amplitudes of hyperons in a scheme of mirror matter admixtures in physical hadrons to include the two-body non-leptonic decays of $\\Omega^-$ and the two photon and two pion decays of kaons. We show that the so-called parity-conserving amplitudes predicted for all the decays vanish in the strong flavor SU(3) symmetry limit. We also establish the specific conditions under which the corresponding so-called parity-violating amplitudes vanish in the same limit.
Amplitude Modulation in the δ Sct star KIC 7106205
Directory of Open Access Journals (Sweden)
Bowman Dominic. M.
2015-01-01
Full Text Available The δ Sct star KIC 7106205 showed amplitude modulation in a single p mode, whilst all other p and g modes remained stable in amplitude and phase over 1470 d of the Kepler dataset. The data were divided into 30 time bins of equal length and a series of consecutive Fourier transforms was calculated. A fixed frequency, calculated from a least-squares fit of all data, allowed amplitude and phase for every mode in each time bin to be tracked. The missing p mode energy was not transferred to any other visible modes.
Scattering Amplitudes: The Most Perfect Microscopic Structures in the Universe
Energy Technology Data Exchange (ETDEWEB)
Dixon, Lance J.; /CERN /SLAC
2011-11-04
This article gives an overview of many of the recent developments in understanding the structure of relativistic scattering amplitudes in gauge theories ranging from QCD to N = 4 super-Yang-Mills theory, as well as (super)gravity. I also provide a pedagogical introduction to some of the basic tools used to organize and illuminate the color and kinematic structure of amplitudes. This article is an invited review introducing a special issue of Journal of Physics A devoted to 'Scattering Amplitudes in Gauge Theories'.
Fatigue independent amplitude-frequency correlations in EMG signals
Siemienski, A; Klajner, P; Siemienski, Adam; Kebel, Alicja; Klajner, Piotr
2006-01-01
In order to assess fatigue independent amplitude-frequency correlations in EMG signals we asked nineteen male subjects to perform a series of isometric muscular contractions by extensors of the knee joint. Different amplitudes of the signal were due to randomly varying both the joint moment and the overall amplification factor of the EMG apparatus. Mean and median frequency, RMS and mean absolute value were calculated for every combination of joint moment and amplification at the original sampling rate of 5 kHz and at several simulated lower sampling rates. Negative Spearman and Kendall amplitude-frequency correlation coefficients were found, and they were more pronounced at high sampling rates.
ANOMALOUS INTERNAL FRICTION PEAKS AS FUNCTION OF STRAIN AMPLITUDE
Kê, T.
1985-01-01
Anelasticity, as suggested by Zener /1/ in 1948, gives rise to internal friction which is independent of the strain amplitude. The internal friction which increases with an increase of strain amplitude was explained by Koehler /2/ and Granato and Lücke /3/ in terms of vibration string and unpinning of dislocations. Early in 1949, Kê /4, 5/ observed in slightly cold-worked dilute aluminium-copper solid solutions a pronounced internal friction peak as a function of strain amplitude in which the...
On the collinear limit of scattering amplitudes at strong coupling
Basso, Benjamin; Vieira, Pedro
2015-01-01
In this letter we consider the collinear limit of gluon scattering amplitudes in planar N=4 SYM theory at strong coupling. We argue that in this limit scattering amplitudes map into correlators of twist fields in the two dimensional non-linear O(6) sigma model, similar to those appearing in recent studies of entanglement entropy. We provide evidence for this assertion by combining the intuition springing from the string worldsheet picture and the predictions coming from the OPE series. One of the main implications of these considerations is that scattering amplitudes receive equally important contributions at strong coupling from both the minimal string area and its fluctuations in the sphere.
Statistical multiresolution analysis in amplitude-frequency domain
Institute of Scientific and Technical Information of China (English)
SUN Hong; GUAN Bao; Henri Maitre
2004-01-01
A concept of statistical multiresolution analysis in amplitude-frequency domain is proposed, which is to employ the wavelet transform on the statistical character of a signal in amplitude domain. In terms of the theorem of generalized ergodicity, an algorithm to estimate the transform coefficients based on the amplitude statistical multiresolution analysis (AMA) is presented. The principle of applying the AMA to Synthetic Aperture Radar (SAR) image processing is described, and the good experimental results imply that the AMA is an efficient tool for processing of speckled signals modeled by the multiplicative noise.
Glauber exchange amplitudes. [electron scattering from H atoms
Madan, R. N.
1975-01-01
The extrapolation method of Ochkur, valid for intermediate energies (about 50 eV), is applied to the exchange form of the Glauber amplitudes. In the case of elastic scattering of electrons from hydrogen atoms at 54.4 Ev the 'post' and 'prior' forms of the exchange amplitude are equivalent, whereas for the case of inelastic scattering there is a minute discrepancy between the two forms of the amplitude. The results are compared with the close-coupling calculation. The investigation is expected to be useful for optically forbidden exchange-allowed transitions due to electron impact at intermediate energies.
MEASUREMENT OF ANGULAR VIBRATION AMPLITUDE BY ACTIVELY BLURRED IMAGES
Institute of Scientific and Technical Information of China (English)
GUAN Baiqing; WANG Shigang; LIU Chong; LI Qian
2007-01-01
A novel motion-blur-based method for measuring the angular amplitude of a high-frequency rotational vibration is schemed. The proposed approach combines the active vision concept and the mechanism of motion-from-blur, generates motion blur on the image plane actively by extending exposure time, and utilizes the motion blur information in polar images to estimate the angular amplitude of a high-frequency rotational vibration. This method obtains the analytical results of the angular vibration amplitude from the geometric moments of a motion blurred polar image and an unblurred image for reference. Experimental results are provided to validate the presented scheme.
Fringe free holographic measurements of large amplitude vibrations
Joud, Fadwa; Laloë, Franck; Michael, Atlan; Hare, Jean; Gross, Michel
2010-01-01
In the measurement of the amplitude of vibration of objects, holographic imaging techniques usually involve fringe counting; due to the limited resolution of images, measurements of large amplitudes are not accessible. We demonstrate a technique that suppresses the necessity of fringe counting: frequency sideband imaging, where the order of the sideband is considered as a marker of the amplitude. The measurement is completely local: no comparison with another reference point on the object is necessary. It involves a sharp variation of a signal, which makes it robust against perturbations. The method is demonstrated in an experiment made with a vibrating clarinet reed; phase modulations as large as 1000 radians have been measured.
Numerical evaluation of one-loop QCD amplitudes
DEFF Research Database (Denmark)
Badger, Simon David; Biedermann, Benedikt; Uwer, Peter
2012-01-01
We present the publicly available program NGluon allowing the numerical evaluation of primitive amplitudes at one-loop order in massless QCD. The program allows the computation of one-loop amplitudes for an arbitrary number of gluons. The focus of the present article is the extension to one......-loop amplitudes including an arbitrary number of massless quark pairs. We discuss in detail the algorithmic differences to the pure gluonic case and present cross checks to validate our implementation. The numerical accuracy is investigated in detail....
Grover's quantum search algorithm for an arbitrary initial amplitude distribution
Biham, E; Biron, D; Grassl, M; Lidar, D A; Biham, Eli; Biham, Ofer; Biron, David; Grassl, Markus; Lidar, Daniel A.
1999-01-01
Grover's algorithm for quantum searching of a database is generalized to deal with arbitrary initial complex amplitude distributions. This renders the algorithm useful as a general search subroutine in a larger quantum computation. First order linear difference equations are found for the time evolution of the amplitudes of the marked and unmarked states. These equations are solved exactly. New expressions are derived for the optimal measurement time and the maximal probability of success. They are found to depend on the averages and variances of the initial amplitude distributions of the marked and unmarked states, but not on higher moments.
Direct Calculation of the Scattering Amplitude Without Partial Wave Analysis
Shertzer, J.; Temkin, A.; Fisher, Richard R. (Technical Monitor)
2001-01-01
Two new developments in scattering theory are reported. We show, in a practical way, how one can calculate the full scattering amplitude without invoking a partial wave expansion. First, the integral expression for the scattering amplitude f(theta) is simplified by an analytic integration over the azimuthal angle. Second, the full scattering wavefunction which appears in the integral expression for f(theta) is obtained by solving the Schrodinger equation with the finite element method (FEM). As an example, we calculate electron scattering from the Hartree potential. With minimal computational effort, we obtain accurate and stable results for the scattering amplitude.
A Color Dual Form for Gauge-Theory Amplitudes
Bern, Zvi
2011-01-01
Recently a duality between color and kinematics has been proposed, exposing a new unexpected structure in gauge theory and gravity scattering amplitudes. Here we propose that the relation goes deeper, allowing us to reorganize amplitudes into a form reminiscent of the standard color decomposition in terms of traces over generators, but with the role of color and kinematics swapped. By imposing additional conditions similar to Kleiss-Kuijf relations between partial amplitudes, the relationship between the earlier form satisfying the duality and the current one is invertible. We comment on extensions to loop level.
DEFF Research Database (Denmark)
Vestergaard, Vitus; Mortensen, Christian Hviid
In recent years many museums have experimented with different approaches to involving users through digital media. We explore how remixing and content sharing can be used as a means for user participation. Remix culture is seen as a culture that allows and encourages the production of derivative...... works; works that are based on already existing works. This cultural practice thrives throughout the Internet, most notably on web2.0 sites like YouTube. The Media Museum has embraced the remix paradigm with the development of an interactive media experience centre called the Media Mixer. Here the...... museum users can produce, deconstruct, reconstruct and finally publish and share digital media content. The media content is created by the user in the museums physical environment, but it can be mixed with material from local or global archives. In that way the gap between the analogue and the digital...
Schooler, C; Flora, J A
1996-01-01
In this review, we focus our discussion on studies examining effects on children and young adults. We believe that the current epidemic of youth violence in the United States justifies a focus on this vulnerable segment of society. We consider media effects on individual children's behaviors, such as imitating aggressive acts. In addition, we examine how the media influence young people's perceptions of norms regarding interpersonal relationships. Next, we assess mass media effects on societal beliefs, or what children and adolescents think the "real world" is like. We suggest these media influences are cumulative and mutually reinforcing, and discuss the implications of repeated exposure to prominent and prevalent violent media messages. Finally, we catalog multiple intervention possibilities ranging from education to regulation. From a public health perspective, therefore, we evaluate the effects that pervasive media messages depicting violence have on young people and present multiple strategies to promote more healthful outcomes. PMID:8724228
Organizational Communication and Media
DEFF Research Database (Denmark)
Tække, Jesper
The paper reflects an interest in the relation between organizational communication and media. It tries to answer the question, how we can observe the relationship between organizational communication and media. It is a work-in-progress which tries to combine organizational studies inspired...... of Niklas Luhmann (Tække & Paulsen 2008, Tække 2008a) with analysis of how organizations communicate in and about media. Using systems theory and form theory, it puts forward a theoretical framework and a strategy for analysing organisational communication in and about media. The medium aspect is inspired...... is a possible framework to draw the two disciplines together in, because it is a theory about the relation between the social and the media it is based on. First the paper sum up the Luhmann inspired theory about organizations, fleshing out how organizations are thought to communicate in and about media and how...
Dematerialization through electronic media?
Coroama, Vlad C; Moberg, Åsa; Hilty, Lorenz
2015-01-01
While the traditional roles of the computer as a machine for scientific calculations, text editing, and graphic design are still significant, computers are increasingly perceived as means of accessing information and interacting with other people – i.e., as electronic media. The aim of this chapter is to analyze digital electronic media and their effects on environmental sustainability. Two fields of application are addressed: electronic media that may replace or augment traditional print med...
Dorenda-Zaborowicz, Marta
2012-01-01
The precise definition of social media marketing is hard to establish, but it can be said that it is the methodical use of new technologies and social networks to achieve specific goals for a company. In simple terms social marketing means advertising a company through many different media, like viral videos and blogs, to achieve its maximum exposure. Nevertheless, social media marketing may also refer to advertising certain social issues, such as NGOs’ or civic actions’ promotion. Precyzy...
International Nuclear Information System (INIS)
This paper looks at a proactive approach to media relations whereby news events are planned, shaped, and timed according to their impact and significance. Focus is given to both written materials and media training. Recommendations are given on why media training should be used as well as how press releases and fact sheets should be written to assist reporters in covering complex technologies and project milestones
Organizational Communication and Media
Tække, Jesper
2008-01-01
The paper reflects an interest in the relation between organizational communication and media. It tries to answer the question, how we can observe the relationship between organizational communication and media. It is a work-in-progress which tries to combine organizational studies inspired of Niklas Luhmann (Tække & Paulsen 2008, Tække 2008a) with analysis of how organizations communicate in and about media. Using systems theory and form theory, it puts forward a theoretical framework a...
Editorial: Pedagogical Media Ecologies
Dorothee M. Meister; Theo Hug; Friesen Norm
2014-01-01
From educational gaming through portable e-readers to cell phones, media are interpenetrating educational spaces and activities. Accordingly, understanding media in environmental or ecological terms has become increasingly important for education internationally. In North America, for example, the centenary of McLuhan’s birth has focused attention on approaches to media – whether oral, textual, electronic or digital– as a kind of environment in which education takes place. In parts of Europe,...
Orchestrating the Media Collage
Ohler, Jason
2009-01-01
Modern literacy has always meant being able to both read and write narrative in the media forms of the day, whatever they may be. Just being able to read is not sufficient. A new dimension of literacy is now in play--namely, the ability to adapt to new media forms and fit them into the overall media collage quickly and effectively. A strong case…
Pellikka, H. (Harri)
2014-01-01
As social media keeps expanding and alternatives for existing services arise, the need for engaging and sustaining users increases as well. One method for engaging users is the use of gamification. The purpose of this study was to found a basis of knowledge of the current state of gamification social media. The study was conducted as qualitative content analysis, analysing 18 social media sites of different types. The analysis concentrated on the game elements incorporated i...
Hernández López, Javier
2014-01-01
Los objetivos de este proyecto fin de carrera son: • Revisar de las experiencias disponibles acerca de la generación de biogás en biodigestores de bajo costo, y el aprovechamiento del biogás para cubrir las necesidades energéticas que se dan en la Vaquería 101, perteneciente a la empresa pecuaria Camilo Cienfuegos y ubicada en la provincia cubana de Pinar del Río. • Determinar el potencial de biomasa generado por el ganado vacuno de la vaquería. • Diseñar el sistema de gene...
Antennas in inhomogeneous media
Galejs, Janis; Fock, V A; Wait, J R
2013-01-01
Antennas in Inhomogeneous Media details the methods of analyzing antennas in such inhomogeneous media. The title covers the complex geometrical configurations along with its variational formulations. The coverage of the text includes various conditions the antennas are subjected to, such as antennas in the interface between two media; antennas in compressible isotropic plasma; and linear antennas in a magnetoionic medium. The selection also covers insulated loops in lossy media; slot antennas with a stratified dielectric or isotropic plasma layers; and cavity-backed slot antennas. The book wil
Sosiaalinen media ja markkinointi
Salmela, Mikko
2014-01-01
Opinnäytetyön toimeksiantajana oli mainostoimisto Media M1. Media M1 on Jyväskyläläinen mainostoimisto, jossa suunnitellaan ja toteutetaan markkinointia printti- ja digimedioihin. Opinnäytetyön aiheeksi valittiin sosiaalinen media ja sen hyödyntäminen markkinoinnissa. Nykyaikana yhä useampi yritys on alkanut siirtyä markkinoimaan myös sosiaalisessa mediassa. Tämän takia Media M1 halusi saada ajankohtaisen selvityksen palveluiden tilanteesta. Opinnäytetyössä selvitettiin sosiaalisen median...
O'Keeffe, Gwenn Schurgin
2012-06-01
Pediatricians care for children's growth and development from the time they are born until they become adults. In addition, pediatricians must be vigilant for external influences. Technology influences children of all ages. Seventy-five percent of teenagers own cell phones, with 25% using them for social media. Technology can lead to an increase in skills and social benefits but there is also the potential for harm such as sexting, cyberbullying, privacy issues, and Internet addiction, all of which can affect health. Pediatricians must become well versed in the new media to provide media-oriented anticipatory guidance and advice on media-related issues. PMID:22643166
Dewdney, Andrew
2013-01-01
The new edition of The Digital Media Handbook presents an essential guide to the historical and theoretical development of digital media, emphasising cultural continuity alongside technological change, and highlighting the emergence of new forms of communication in contemporary networked culture.Andrew Dewdney and Peter Ride present detailed critical commentary and descriptive historical accounts, as well as a series of interviews from a range of digital media practitioners, including producers, developers, curators and artists.The Digital Media Handbook highlights key concerns of today's prac
Rawnsley, Gary D.; Rawnsley, Ming-Yeh T.
2008-01-01
Media reform is a valuable indicator of democratisation. It provides an abundance of information about the levels of freedom, tolerance, social justice and pluralism within a political system. This article reviews the changes in the Taiwanese media that have occurred since the lifting of martial law in 1987 and considers how the media are faring at the beginning of Chen Shui-bian’s second term. Taiwan’s media are still at an early stage of democratisation but it cannot be denied that progress...
All tree-level amplitudes in massless QCD
Energy Technology Data Exchange (ETDEWEB)
Dixon, Lance [Theory Group, Physics Department, CERN, Ch-1211 Geneva 23 (Switzerland); SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94309 (United States); Henn, Johannes; Plefka, Jan; Schuster, Theodor [Institut fuer Physik, Humboldt-Universitaet, Newtonstrasse 15, D-12489 Berlin (Germany)
2011-07-01
We derive compact analytical formulae for all tree-level color-ordered gauge theory amplitudes involving any number of external gluons and up to three massless quark-anti-quark pairs. A general formula for all gluon-gluino tree amplitudes is presented, based on the combinatorics of paths along a rooted tree and associated determinants. Our results are obtained by projecting the previously-found expressions for the super-amplitudes of the maximally supersymmetric super Yang-Mills theory (N=4 SYM) onto the relevant components. We show how these results carry over to the corresponding QCD amplitudes, including massless quarks of different flavors as well as a single electroweak vector boson. The public Mathematica package GGT is described, which encodes the results of this work and yields analytical formulae for all N = 4 SYM gluon-gluino trees. These in turn yield all QCD trees with up to four external arbitrary-flavored massless quark-anti-quark-pairs.
Moments of pseudoscalar meson distribution amplitudes from the lattice
International Nuclear Information System (INIS)
Based on lattice simulations with two flavors of dynamical, O(a)-improved Wilson fermions we present results for the first two moments of the distribution amplitudes of pseudoscalar mesons at several values of the valence quark masses. By extrapolating our results to the physical masses of up/down and strange quarks, we find the first two moments of the K+ distribution amplitude and the second moment of the π+ distribution amplitude. We use nonperturbatively determined renormalization coefficients to obtain results in the MS scheme. At a scale of 4 GeV2 we find a2π=0.201(114) for the second Gegenbauer moment of the pion's distribution amplitude, while for the kaon, a1K=0.0453(9)(29) and a2K=0.175(18)(47)
Cluster Functions and Scattering Amplitudes for Six and Seven Points
Harrington, Thomas
2015-01-01
Scattering amplitudes in planar super-Yang-Mills theory satisfy several basic physical and mathematical constraints, including physical constraints on their branch cut structure and various empirically discovered connections to the mathematics of cluster algebras. The power of the bootstrap program for amplitudes is inversely proportional to the size of the intersection between these physical and mathematical constraints: ideally we would like a list of constraints which determine scattering amplitudes uniquely. We explore this intersection quantitatively for two-loop six- and seven-point amplitudes by providing a complete taxonomy of the Gr(4,6) and Gr(4,7) cluster polylogarithm functions of arXiv:1401.6446 at weight 4.
Toward a unified description of hadro- and photoproduction amplitudes
Paris, M W; Workman, R L; Briscoe, W J; Strakovsky, I I
2010-01-01
The near-term objectives of the research program at the Data Analysis Center are established within the context of the existing partial wave analyses available through the online suite of analysis and database codes accessible through SAID, the Scattering Analysis Interactive Database. This presentation reviews the efforts to determine a model independent method to obtain sets of partial wave amplitudes for strong and electromagnetic reactions, the interpretation of the amplitudes in terms of the excited states of the nucleon, the role of new precision unpolarized and polarized data, and new developments aimed at determining the photoproduction mulitpoles in a unitary, coupled-channel approach. The Chew-Mandelstam technique is discussed and applied to the problem of the S-wave pion- and eta-photoproduction amplitudes. The resulting eta production amplitudes exhibit the expected resonant behavior near the eta production threshold. Application of this method to a unified description of the hadro- and photoprodu...
N >= 4 Supergravity Amplitudes from Gauge Theory at Two Loops
Boucher-Veronneau, C
2011-01-01
We present the full two-loop four-graviton amplitudes in N=4,5,6 supergravity. These results were obtained using the double-copy structure of gravity, which follows from the recently conjectured color-kinematics duality in gauge theory. The two-loop four-gluon scattering amplitudes in N=0,1,2 supersymmetric gauge theory are a second essential ingredient. The gravity amplitudes have the expected infrared behavior: the two-loop divergences are given in terms of the squares of the corresponding one-loop amplitudes. The finite remainders are presented in a compact form. The finite remainder for N=8 supergravity is also presented, in a form that utilizes a pure function with a very simple symbol.
Movement amplitude and tempo change in piano performance
Palmer, Caroline
2001-05-01
Music performance places stringent temporal and cognitive demands on individuals that should yield large speed/accuracy tradeoffs. Skilled piano performance, however, shows consistently high accuracy across a wide variety of rates. Movement amplitude may affect the speed/accuracy tradeoff, so that high accuracy can be obtained even at very fast tempi. The contribution of movement amplitude changes in rate (tempo) is investigated with motion capture. Cameras recorded pianists with passive markers on hands and fingers, who performed on an electronic (MIDI) keyboard. Pianists performed short melodies at faster and faster tempi until they made errors (altering the speed/accuracy function). Variability of finger movements in the three motion planes indicated most change in the plane perpendicular to the keyboard across tempi. Surprisingly, peak amplitudes of motion before striking the keys increased as tempo increased. Increased movement amplitudes at faster rates may reduce or compensate for speed/accuracy tradeoffs. [Work supported by Canada Research Chairs program, HIMH R01 45764.
The Last of the Finite Loop Amplitudes in QCD
Energy Technology Data Exchange (ETDEWEB)
Bern, Zvi; Dixon, Lance J.; Kosower, David A.
2005-05-31
We use on-shell recursion relations to determine the one-loop QCD scattering amplitudes with a massless external quark pair and an arbitrary number (n - 2) of positive-helicity gluons. These amplitudes are the last of the unknown infrared- and ultraviolet-finite loop amplitudes of QCD. The recursion relations are similar to ones applied at tree level, but contain new non-trivial features corresponding to poles present for complex momentum arguments but absent for real momenta. We present the relations and the compact solutions to them, valid for all n. We also present compact forms for the previously-computed one-loop n-gluon amplitudes with a single negative helicity and the rest positive helicity.
Remarks on the identities of gluon tree amplitudes
International Nuclear Information System (INIS)
Recently, Bjerrum-Bohr, Damgaard, Feng, and Sondergaard derived a set of new interesting quadratic identities of the Yang-Mills (YM) tree scattering amplitudes, besides Bern-Carrasco-Johansson (BCJ) identities. Here we comment that these quadratic identities of YM amplitudes actually follow directly from the KLT (Kawai-Lewellen-Tye) relation for graviton-dilaton-axion scattering amplitudes (in four-dimensional spacetime). This clarifies their physical origin and also provides a simpler version of the new identities. We also comment that the recently discovered BCJ identities of YM helicity amplitudes, at least for the maximal helicity-violating case, can be verified by using (repeatedly) the Schouten identity. We also point out additional quadratic identities that can be written down from the KLT relations.
Some tree-level string amplitudes in the NSR formalism
Becker, Katrin; Melnikov, Ilarion V; Robbins, Daniel; Royston, Andrew B
2015-01-01
We calculate tree level scattering amplitudes for open strings using the NSR formalism. We present a streamlined symmetry-based and pedagogical approach to the computations, which we first develop by checking two-, three-, and four-point functions involving bosons and fermions. We calculate the five-point amplitude for massless gluons and find agreement with an earlier result by Brandt, Machado and Medina. We then compute the five-point amplitudes involving two and four fermions respectively, the general form of which has not been previously obtained in the NSR formalism. The results nicely confirm expectations from the supersymmetric $F^4$ effective action. Finally we use the prescription of Kawai, Lewellen and Tye (KLT) to compute the amplitudes for the closed string sector.
Remarks on the identities of gluon tree amplitudes
Tye, S.-H. Henry; Zhang, Yang
2010-10-01
Recently, Bjerrum-Bohr, Damgaard, Feng, and Sondergaard derived a set of new interesting quadratic identities of the Yang-Mills (YM) tree scattering amplitudes, besides Bern-Carrasco-Johansson (BCJ) identities. Here we comment that these quadratic identities of YM amplitudes actually follow directly from the KLT (Kawai-Lewellen-Tye) relation for graviton-dilaton-axion scattering amplitudes (in four-dimensional spacetime). This clarifies their physical origin and also provides a simpler version of the new identities. We also comment that the recently discovered BCJ identities of YM helicity amplitudes, at least for the maximal helicity-violating case, can be verified by using (repeatedly) the Schouten identity. We also point out additional quadratic identities that can be written down from the KLT relations.
Some tree-level string amplitudes in the NSR formalism
Becker, Katrin; Becker, Melanie; Melnikov, Ilarion V.; Robbins, Daniel; Royston, Andrew B.
2015-12-01
We calculate tree level scattering amplitudes for open strings using the NSR formalism. We present a streamlined symmetry-based and pedagogical approach to the computations, which we first develop by checking two-, three-, and four-point functions involving bosons and fermions. We calculate the five-point amplitude for massless gluons and find agreement with an earlier result by Brandt, Machado and Medina. We then compute the five-point amplitudes involving two and four fermions respectively, the general form of which has not been previously obtained in the NSR formalism. The results nicely confirm expectations from the supersymmetric F 4 effective action. Finally we use the prescription of Kawai, Lewellen and Tye (KLT) to compute the amplitudes for the closed string sector.
N >= 4 Supergravity Amplitudes from Gauge Theory at Two Loops
Energy Technology Data Exchange (ETDEWEB)
Boucher-Veronneau, C.; Dixon, L.J.; /SLAC
2012-02-15
We present the full two-loop four-graviton amplitudes in N = 4, 5, 6 supergravity. These results were obtained using the double-copy structure of gravity, which follows from the recently conjectured color-kinematics duality in gauge theory. The two-loop four-gluon scattering amplitudes in N = 0, 1, 2 supersymmetric gauge theory are a second essential ingredient. The gravity amplitudes have the expected infrared behavior: the two-loop divergences are given in terms of the squares of the corresponding one-loop amplitudes. The finite remainders are presented in a compact form. The finite remainder for N = 8 supergravity is also presented, in a form that utilizes a pure function with a very simple symbol.
On the field theory expansion of superstring five point amplitudes
Boels, Rutger H
2013-01-01
A simple recursive expansion algorithm for the integrals of superstring five point amplitudes in a flat background is given which reduces the expansion to simple symbol(ic) manipulations. This approach can be used for instance to prove the expansion is maximally transcendental to all orders and to verify several conjectures made in recent literature to high order. Starting at order eighteen for instance new identities for products of certain matrices associated to single (odd) zeta values are identified. For closed strings apart from generalities in particular the maximal R-symmetry violating amplitudes in type IIB superstring theory are studied. The obtained expansion of the open string amplitudes reduces the analysis for MRV amplitudes to the classification of completely symmetric polynomials of the external legs, up to momentum conservation. Using Molien's theorem as a counting tool this problem is solved by constructing an explicit nine element basis for this class. This theorem may be of wider interest: ...
Pulse amplitude extraction in digital nuclear spectrometer system
International Nuclear Information System (INIS)
Background: The accuracy and real-time performance of pulse amplitude extraction in digital nuclear spectrometer system directly influence the system energy resolution and the maximum count rates. Purpose: This paper attempts to study the amplitude extraction method of digital nuclear signal, which comes from the high speed ADC. Methods: In this paper, according to the principle of operation, the extraction method is categorized into three types: direct comparison method, curve fitting method and filter shaper method, also the operating principle of the three methods are analysed and discussed. Results: The above three methods are employed to process actual sampled digital nuclear signal at the sampling frequency of 40 MHz, the curve fitting method and filter shaper method are respectively used to extract the pulse amplitude and get their energy spectrum. Conclusions: Taking into account the resolution and pulse counting rate, after theoretical analysis, experimental comparison and test, the optimal pulse amplitude extraction method is filter shaper method. (authors)
Moments of pseudoscalar meson distribution amplitudes from the lattice
International Nuclear Information System (INIS)
Based on lattice simulations with two flavours of dynamical, O(a)-improved Wilson fermions we present results for the first two moments of the distribution amplitudes of pseudoscalar mesons at several values of the valence quark masses. By extrapolating our results to the physical masses of up/down and strange quarks, we find the first two moments of the K+ distribution amplitude and the second moment of the π+ distribution amplitude. We use nonperturbatively determined renormalisation coefficients to obtain results in the anti M anti S scheme. At a scale of 4 GeV2 we find a2π=0.201(114) for the second Gegenbauer moment of the pion's distribution amplitude, while for the kaon, aK1=0.0453(9)(29) and aK1=0.175(18)(47). (Orig.)
CP violation due to new ΔB = 1 amplitudes
International Nuclear Information System (INIS)
The authors make a systematic analysis of the effects of new physics in the B decay amplitudes on the CP asymmetries in neutral B decays. Although these are expected to be smaller than new physics effects on the mixing amplitude, they are easier to probe in some cases. The effects of new contributions to the mixing amplitude are felt universally across all decay modes, whereas the effects of new decay amplitudes could vary from mode to mode. In particular the prediction that the CP asymmetries in the B decay modes with b → c anti cs, b → c anti cd, b → c anti ud and b → s anti ss should all measure the same quantity (sin 2β in the Standard Model) could be violated
Beyond Reggeization for two- and three-loop QCD amplitudes
Del Duca, Vittorio; Magnea, Lorenzo; Vernazza, Leonardo
2013-01-01
The high-energy factorization of gauge theory scattering amplitudes in terms of universal impact factors and a Reggeized exchange in the $t$-channel, corresponding to a Regge pole in the angular momentum plane, is know to conflict with the structure of soft anomalous dimensions starting at the two-loop level. We explore the implications of this violation of factorization for two- and three-loop QCD amplitudes: first we propose criteria to organize the amplitudes into factorizing and non-factorizing terms, then we test them by recovering a known result for non-logarithmic terms at two loops. Finally we predict the precise value of the leading non-factorizing energy logarithms at three loops, and we uncover a set of all-order identities constraining infrared finite terms in quark and gluon amplitudes.
Lorentz Constraints on Massive Three-Point Amplitudes
Conde, Eduardo
2016-01-01
We explore the non-perturbative constraints that Lorentz symmetry imposes on scattering amplitudes where the asymptotic states can be massive. As it is well known, in the case of only massless states the three-point amplitude is fixed by these constraints plus some physical requirements. We find that a similar statement can be made when some of the particles have mass. We first derive the generic functional form that the three-point amplitude must have by virtue of Lorentz symmetry, which depends on an arbitrary function. By imposing a "UV massive = massless" condition, we find that the arbitrary function appearing in the amplitude with one massive particle can be fixed. For two and three massive particles, the arbitrary functions are also fixed in a particular Lorentz frame, which corresponds to projecting all the massive momenta along the same null momentum.
Utility of Amplitude-Integrated EEG in the NICU
J Gordon Millichap
2009-01-01
The problem of artifacts in using the amplitude-integrated electroencephalogram (AIE) to assess cortical function in premature infants in the NICU were studied at Weill Cornell Medical College, New York, NY.
High Amplitude (delta)-Scutis in the Large Magellanic Cloud
Energy Technology Data Exchange (ETDEWEB)
Garg, A; Cook, K H; Nikolaev, S; Huber, M E; Rest, A; Becker, A C; Challis, P; Clocchiatti, A; Miknaitis, G; Minniti, D; Morelli, L; Olsen, K; Prieto, J L; Suntzeff, N B; Welch, D L; Wood-Vasey, W M
2010-01-25
The authors present 2323 High-Amplitude {delta}-Scutis (HADS) candidates discovered in the Large Magellanic Cloud (LMC) by the SuperMACHO survey (Rest et al. 2005). Frequency analyses of these candidates reveal that several are multimode pulsators, including 119 whose largest amplitude of pulsation is in the fundamental (F) mode and 19 whose largest amplitude of pulsation is in the first overtone (FO) mode. Using Fourier decomposition of the HADS light curves, they find that the period-luminosity (PL) relation defined by the FO pulsators does not show a clear separation from the PL-relation defined by the F pulsators. This differs from other instability strip pulsators such as type c RR Lyrae. They also present evidence for a larger amplitude, subluminous population of HADS similar to that observed in Fornax (Poretti et al. 2008).
Mean amplitudes of vibration of OTeF5-
International Nuclear Information System (INIS)
Mean amplitudes of vibration for OTeF5- have been calculated from known spectroscopic and structural data in a wide temperature range. The results are briefly discussed in comparison with those of related species. (author)
Square-root pulse amplitude-to-digital converter
International Nuclear Information System (INIS)
A device for converting pulse amplitudes from gas-discharged detectors of ionizing radiations to digits is described. Minimum of losses of energy resolution, expenditure of operating memory volume, spectrum set and processing times are provided with use a linear atomic numbers scale and constancy of peak widths of x-ray spectrum. The converter is placed on two separate circuit boards of an analogous amplitude-time converter (ATC) and digital control unit. The signal amplitude in ATC is compared with periodical reference voltage of a parabolic form generated with two analogous integrators. For 256 channels a maximum dead system time is 25.6 μs, mean time-13 μs, amplitude range-0.1-6v, pulse duration - 0.3-300 μs. The converter described is used for a long time under laboratory and field corditiosns in a portable x-ray spectrometer
General tree-level amplitudes by factorization limits
Energy Technology Data Exchange (ETDEWEB)
Zhou, Kang; Qiao, Chenkai [Zhejiang University, Zhejiang Institute of Modern Physics, Hangzhou (China)
2015-04-01
To find boundary contributions is a rather difficult problem when applying the BCFW recursion relation. In this paper, we propose an approach to bypass this problem by calculating general tree amplitudes that contain no polynomial using factorization limits. More explicitly, we construct an expression iteratively, which produces the correct factorization limits for all physical poles, and does not contain other poles, then it should be the correct amplitude. To some extent, this approach can be considered as an alternative way to find boundary contributions. To demonstrate our approach, we present several examples: φ{sup 4} theory, pure gauge theory, Einstein-Maxwell theory, and Yukawa theory. While the amplitude allows the existence of polynomials which satisfy the correct mass dimension and helicities, this approach is not applicable to determining the full amplitude. (orig.)
Off-shell amplitudes for nonoriented closed strings
Cappiello, L; Pettorino, R; Pezzella, F
1998-01-01
In the context of the bosonic closed string theory, by using the operatorial formalism, we give a simple expression of the off-shell amplitude with an arbitrary number of external massless states inserted on the Klein bottle.
Analytic Computations of Massive One-Loop Amplitudes
Badger, Simon; Yundin, Valery
2010-01-01
We show some new applications of on-shell methods to calculate compact helicity amplitudes for t tbar production through gluon fusion. The rational and mass renormalisation contributions are extracted from two independent Feynman diagram based approaches.
Amplitude chimeras and chimera death in dynamical networks
Zakharova, Anna; Kapeller, Marie; Schöll, Eckehard
2016-06-01
We find chimera states with respect to amplitude dynamics in a network of Stuart- Landau oscillators. These partially coherent and partially incoherent spatio-temporal patterns appear due to the interplay of nonlocal network topology and symmetry-breaking coupling. As the coupling range is increased, the oscillations are quenched, amplitude chimeras disappear and the network enters a symmetry-breaking stationary state. This particular regime is a novel pattern which we call chimera death. It is characterized by the coexistence of spatially coherent and incoherent inhomogeneous steady states and therefore combines the features of chimera state and oscillation death. Additionally, we show two different transition scenarios from amplitude chimera to chimera death. Moreover, for amplitude chimeras we uncover the mechanism of transition towards in-phase synchronized regime and discuss the role of initial conditions.
Amplitude sorting of oscillatory burst signals by sampling
Davis, Thomas J.
1977-01-01
A method and apparatus for amplitude sorting of oscillatory burst signals is described in which the burst signal is detected to produce a burst envelope signal and an intermediate or midportion of such envelope signal is sampled to provide a sample pulse output. The height of the sample pulse is proportional to the amplitude of the envelope signal and to the maximum burst signal amplitude. The sample pulses are fed to a pulse height analyzer for sorting. The present invention is used in an acoustic emission testing system to convert the amplitude of the acoustic emission burst signals into sample pulse heights which are measured by a pulse height analyzer for sorting the pulses in groups according to their height in order to identify the material anomalies in the test material which emit the acoustic signals.
Fermion-fermion and boson-boson amplitudes: surprising similarities
Dvoeglazov, Valeri V
2007-01-01
Amplitudes for fermion-fermion, boson-boson and fermion-boson interactions are calculated in the second order of perturbation theory in the Lobachevsky space. An essential ingredient of the model is the Weinberg's 2(2j+1)-component formalism for describing a particle of spin j. The boson-boson amplitude is then compared with the two-fermion amplitude obtained long ago by Skachkov on the basis of the Hamiltonian formulation of quantum field theory on the mass hyperboloid, p_0^2 - p^2=M^2, proposed by Kadyshevsky. The parametrization of the amplitudes by means of the momentum transfer in the Lobachevsky space leads to same spin structures in the expressions of T-matrices for the fermion case and the boson case. However, certain differences are found. Possible physical applications are discussed.
Amplitude fluctuations in the Berezinskii-Kosterlitz-Thouless phase
Jakubczyk, Pawel
2016-01-01
We analyze the interplay of thermal amplitude and phase fluctuations in a $U(1)$ symmetric two-dimensional $\\phi^4$-theory. To this end, we derive coupled renormalization group equations for both types of fluctuations. Discarding the amplitude fluctuations, the expected Berezinskii-Kosterlitz-Thouless (BKT) phase characterized by a finite phase stiffness and an algebraic decay of order parameter correlations is recovered at low temperatures. However, in contrast to the widespread expectation, amplitude fluctuations are not innocuous, since their mass vanishes due to a strong renormalization by phase fluctuations. Even at low temperatures the amplitude fluctuations lead to a logarithmic renormalization group flow of the phase stiffness, which ultimately vanishes. Hence, the BKT phase is strictly speaking replaced by a symmetric phase with a finite correlation length, which is however exponentially large at low temperatures. The vortex-driven BKT transition is then rounded to a crossover, which may be practical...
Broadband metasurface for independent control of reflected amplitude and phase
Sheng Li Jia; Xiang Wan; Pei Su; Yong Jiu Zhao; Tie Jun Cui
2016-01-01
We propose an ultra-thin metasurface to control the amplitudes and phases independently of the reflected waves by changing geometries and orientations of I-shaped metallic particles. We demonstrate that the particles can realize independent controls of reflection amplitudes and phases with a magnitude range of [0, 0.82] and a full phase range of 360° in broad frequency band. Based on such particles, two ultrathin metasurface gratings are further proposed to form anomalous reflection with pola...
Dimensionless Amplitude of the Internal Acoustic Filed in Flue Instruments
Hirschberg, Abraham; Verge, Marc-Pierre; Wijnands, A. P. J.
1995-01-01
Dimensionless representation of the pressure signal measured inside a flue organ pipe shows thatthe dimensionless amplitude is a function of the Strouhal number only. This behavior indicatesthat amplitude saturation is due to a non-linear interaction of the acoustic flow with the jet flow.Correlation of these results with flow visualizations stresses the importance of vortex shedding atthe edge of the labium. (...)The aim of the present paper is to demonstrate the power of dimensionless repre...
Threshold amplitudes for transition to turbulence in a pipe
Trefethen, Lloyd N.; Chapman, S. J.; Henningson, Dan S.; Meseguer, A.; Mullin, Tom; Nieuwstadt, F.T.M.
2000-01-01
Although flow in a circular pipe is stable to infinitesimal perturbations, it can be excited to turbulence by finite perturbations whose minimal amplitude shrinks as $R \\rightarrow \\infty ~(R =$ Reynolds number). Laboratory experiments have appeared to disagree with one another and with theoretical predictions about the dependence of this minimal amplitude on $R$, with published results ranging approximately from $R^{-1/4}$ to $R^{-3/2}$. Here it is shown that these discrepancies can be expla...
On Superstring Disk Amplitudes in a Rolling Tachyon Background
Jokela, Niko; Keski-Vakkuri, Esko; Majumder, Jaydeep
2005-01-01
We study the tree level scattering or emission of n closed superstrings from a decaying non-BPS brane in Type II superstring theory. We attempt to calculate generic n-point superstring disk amplitudes in the rolling tachyon background. We show that these can be written as infinite power series of Toeplitz determinants, related to expectation values of a periodic function in Circular Unitary Ensembles. Further analytical progress is possible in the special case of bulk-boundary disk amplitudes...
Large-N QCD and the Veneziano amplitude
Armoni, Adi
2016-05-01
We consider four scalar mesons scattering in large-Nc QCD. Using the worldline formalism we show that the scattering amplitude can be written as a formal sum over Wilson loops. The AdS/CFT correspondence maps this sum into a sum over string worldsheets in a confining background. We then argue that for well separated mesons the sum is dominated by flat space configurations. Under additional assumptions about the dual string path integral we obtain the Veneziano amplitude.
Optimization of phase contrast in bimodal amplitude modulation AFM
Mehrnoosh Damircheli; Amir F. Payam; Ricardo Garcia
2015-01-01
Bimodal force microscopy has expanded the capabilities of atomic force microscopy (AFM) by providing high spatial resolution images, compositional contrast and quantitative mapping of material properties without compromising the data acquisition speed. In the first bimodal AFM configuration, an amplitude feedback loop keeps constant the amplitude of the first mode while the observables of the second mode have not feedback restrictions (bimodal AM). Here we study the conditions to enhance the ...
The asymptotics of an amplitude for the 4-simplex
Barrett, John W.; Williams, Ruth M.
1998-01-01
An expression for the oscillatory part of an asymptotic formula for the relativistic spin network amplitude for a 4-simplex is given. The amplitude depends on specified areas for each two-dimensional face in the 4-simplex. The asymptotic formula has a contribution from each flat Euclidean metric on the 4-simplex which agrees with the given areas. The oscillatory part of each contribution is determined by the Regge calculus Einstein action for that geometry.
Bootstrapping a Five-Loop Amplitude from Steinmann Relations
Caron-Huot, Simon; McLeod, Andrew; von Hippel, Matt
2016-01-01
The analytic structure of scattering amplitudes is restricted by Steinmann relations, which enforce the vanishing of certain discontinuities of discontinuities. We show that these relations dramatically simplify the function space for the hexagon function bootstrap in planar maximally supersymmetric Yang-Mills theory. Armed with this simplification, along with the constraints of dual conformal symmetry and Regge exponentiation, we obtain the complete five-loop six-particle amplitude.
Large-N QCD and the Veneziano amplitude
Directory of Open Access Journals (Sweden)
Adi Armoni
2016-05-01
Full Text Available We consider four scalar mesons scattering in large-Nc QCD. Using the worldline formalism we show that the scattering amplitude can be written as a formal sum over Wilson loops. The AdS/CFT correspondence maps this sum into a sum over string worldsheets in a confining background. We then argue that for well separated mesons the sum is dominated by flat space configurations. Under additional assumptions about the dual string path integral we obtain the Veneziano amplitude.
Amplitude equations and pattern selection in Faraday waves
Chen, Peilong; Vinals, Jorge
1997-01-01
A nonlinear theory of pattern selection in parametric surface waves (Faraday waves) is presented that is not restricted to small viscous dissipation. By using a multiple scale asymptotic expansion near threshold, a standing wave amplitude equation is derived from the governing equations. The amplitude equation is of gradient form, and the coefficients of the associated Lyapunov function are computed for regular patterns of various symmetries as a function of a viscous damping parameter gamma....
On the pion distribution amplitude. Derivation, properties, predictions
Stefanis, N G; Pimikov, A V
2014-01-01
We provide an in-depth analysis of the $\\pi$ distribution amplitude in terms of two different Gegenbauer representations. Detailed predictions for the $\\pi-\\gamma$ transition form factor are presented, obtained with light-cone sum rules. Various $\\pi$ distribution amplitudes are tested and the crucial role of their endpoint behavior in the form-factor analysis is discussed. Comparison with the data is given.
Processing of Amplitudes in Ground Penetrating Radar Method : Applied Samples
International Nuclear Information System (INIS)
In this work, the true processing of amplitude values, which are fourth dimension (4D) in applications of 3D visualization of the ground penetrating radar (GPR) method, colorization and visualization of them are presented. The aim of the data visualization is to decompose any searched geological structure or any object from other anomalies and display successfully. The applied samples confirms how important is true amplitude processing and visualization of them
Weak measurements measure probability amplitudes (and very little else)
Sokolovski, D.
2016-04-01
Conventional quantum mechanics describes a pre- and post-selected system in terms of virtual (Feynman) paths via which the final state can be reached. In the absence of probabilities, a weak measurement (WM) determines the probability amplitudes for the paths involved. The weak values (WV) can be identified with these amplitudes, or their linear combinations. This allows us to explain the "unusual" properties of the WV, and avoid the "paradoxes" often associated with the WM.
Novel clutter map CFAR algorithm with amplitude limiter
Institute of Scientific and Technical Information of China (English)
单涛; 陶然; 王越; 周思永
2004-01-01
The traditional clutter map constant false alarm rate (CM-CFAR) detector is affected by interference and selfmasking[1] which will cause the low probability of detection. To solve these problems, a novel algorithm named clutter map CFAR with amplitude limiter (ALCM-CFAR) is proposed, in which the amplitude of the input signal is limited by a filter. The simulation results prove the effectiveness of ALCM-CFAR algorithm.
Sign and amplitude representation of the forex networks
Sylwia Gworek; Jaroslaw Kwapien; Stanislaw Drozdz
2009-01-01
We decompose the exchange rates returns of 41 currencies (incl. gold) into their sign and amplitude components. Then we group together all exchange rates with a common base currency, construct Minimal Spanning Trees for each group independently, and analyze properties of these trees. We show that both the sign and the amplitude time series have similar correlation properties as far as the core network structure is concerned. There exist however interesting peripheral differences that may open...
Fatigue life assessment under multiaxial variable amplitude loading
International Nuclear Information System (INIS)
A variable amplitude multiaxial fatigue life prediction method is presented in this paper. It is based on a stress as input data are the stress tensor histories which may be calculated by FEM analysis or measured directly on the structure during the service loading. The different steps of he method are first presented then its experimental validation is realized for log and finite fatigue lives through biaxial variable amplitude loading tests using cruciform steel samples. (authors). 9 refs., 7 figs
Amplitude chimeras and chimera death in dynamical networks
Zakharova, Anna; Kapeller, Marie; Schöll, Eckehard
2015-01-01
We find chimera states with respect to amplitude dynamics in a network of Stuart-Landau oscillators. These partially coherent and partially incoherent spatio-temporal patterns appear due to the interplay of nonlocal network topology and symmetry-breaking coupling. As the coupling range is increased, the oscillations are quenched, amplitude chimeras disappear and the network enters a symmetry-breaking stationary state. This particular regime is a novel pattern which we call chimera death. It i...
Three-point disc amplitudes in the RNS formalism
Becker, Katrin; Becker, Melanie; Robbins, Daniel; Su, Ning
2016-06-01
We calculate all tree level string theory vacuum to Dp-brane disc amplitudes involving an arbitrary RR-state and two NS-NS vertex operators. This computation was earlier performed by K. Becker, Guo, and Robbins for the simplest case of a RR-state of type C (p - 3). Here we use the aid of a computer to calculate all possible three-point amplitudes involving a RR-vertex operator of type C (p + 1 + 2 k).
Asymptotic Expansions of Feynman Amplitudes in a Generic Covariant Gauge
Linhares, C. A.; Malbouisson, A. P. C.; Roditi, I.
2006-01-01
We show in this paper how to construct Symanzik polynomials and the Schwinger parametric representation of Feynman amplitudes for gauge theories in an unspecified covariant gauge. The complete Mellin representation of such amplitudes is then established in terms of invariants (squared sums of external momenta and squared masses). From the scaling of the invariants by a parameter we extend for the present situation a theorem on asymptotic expansions, previously proven for the case of scalar fi...
Bulk and edge quasihole tunneling amplitudes in the Laughlin state
Hu, Zi-Xiang; Lee, Ki Hoon; Wan, Xin
2012-01-01
The tunneling between the Laughlin state and its quasihole excitations are studied by using the Jack polynomial. We find a universal analytical formula for the tunneling amplitude, which can describe both bulk and edge quasihole excitations. The asymptotic behavior of the tunneling amplitude reveals the difference and the crossover between bulk and edge states. The effects of the realistic coulomb interaction with a background-charge confinement potential and disorder are also discussed. The ...
Amplitude Relations in Non-linear Sigma Model
Chen, Gang
2013-01-01
In this paper, we investigate tree-level scattering amplitude relations in $U(N)$ non-linear sigma model. We use Calay parametrization. As was shown in the recent works [23,24], both on-shell amplitudes and off-shell currents with odd points have to vanish under Calay parametrization. We prove the off-shell U(1) identity and fundamental BCJ relation for even-point currents. By taking the on-shell limit of the off-shell relations, we show that the color-ordered tree amplitudes with even points satisfy $U(1)$-decoupling identity and fundamental BCJ relation, which have the same formations within Yang-Mills theory. We further state that all the on-shell general KK, BCJ relations as well as the minimal-basis expansion are also satisfied by color-ordered tree amplitudes. As a consequence of the relations among color-ordered amplitudes, the total $2m$-point tree amplitudes satisfy DDM form of color decomposition as well as KLT relation.
Amplitude relations in non-linear sigma model
Chen, Gang; Du, Yi-Jian
2014-01-01
In this paper, we investigate tree-level scattering amplitude relations in U( N) non-linear sigma model. We use Cayley parametrization. As was shown in the recent works [23,24], both on-shell amplitudes and off-shell currents with odd points have to vanish under Cayley parametrization. We prove the off-shell U(1) identity and fundamental BCJ relation for even-point currents. By taking the on-shell limits of the off-shell relations, we show that the color-ordered tree amplitudes with even points satisfy U(1)-decoupling identity and fundamental BCJ relation, which have the same formations within Yang-Mills theory. We further state that all the on-shell general KK, BCJ relations as well as the minimal-basis expansion are also satisfied by color-ordered tree amplitudes. As a consequence of the relations among color-ordered amplitudes, the total 2 m-point tree amplitudes satisfy DDM form of color decomposition as well as KLT relation.
One-loop gluonic amplitudes from single unitarity cuts
Glover, E. W. Nigel; Williams, Ciaran
2008-12-01
We show that one-loop amplitudes in massless gauge theories can be determined from single cuts. By cutting a single propagator and putting it on-shell, the integrand of an n-point one-loop integral is transformed into an (n+2)-particle tree level amplitude. The single-cut approach described here is complementary to the double or multiple unitarity cut approaches commonly used in the literature. In common with these approaches, if the cut is taken in four dimensions, one finds only the cut-constructible parts of the amplitude, while if the cut is in D = 4-2epsilon dimensions, both rational and cut-constructible parts are obtained. We test our method by reproducing the known results for the fully rational all-plus and mostly-plus QCD amplitudes, A(1)4(1+, 2+, 3+, 4+) and A(1)5(1+, 2+, 3+, 4+, 5+). We also rederive expressions for the scalar loop contribution to the four-gluon MHV amplitude, A4(1,Script N = 0)(-, -, +, +) which has both cut-constructible and rational contributions, and the fully cut-constructible n-gluon MHV amplitude in Script N = 4 Supersymmetric Yang-Mills, A4(1,Script N = 4)(-, -, +, ..., +).
Tree-level Amplitudes in the Nonlinear Sigma Model
Kampf, Karol; Trnka, Jaroslav
2013-01-01
We study in detail the general structure and further properties of the tree-level amplitudes in the SU(N) nonlinear sigma model. We construct the flavor-ordered Feynman rules for various parameterizations of the SU(N) fields U(x), write down the Berends-Giele relations for the semi-on-shell currents and discuss their efficiency for the amplitude calculation in comparison with those of renormalizable theories. We also present an explicit form of the partial amplitudes up to ten external particles. It is well known that the standard BCFW recursive relations cannot be used for reconstruction of the the on-shell amplitudes of effective theories like the SU(N) nonlinear sigma model because of the inappropriate behavior of the deformed on-shell amplitudes at infinity. We discuss possible generalization of the BCFW approach introducing "BCFW formula with subtractions" and with help of Berends-Giele relations we prove particular scaling properties of the semi-on-shell amplitudes of the SU(N) nonlinear sigma model und...
Non-MHV tree amplitudes in gauge theory
International Nuclear Information System (INIS)
We show how all non-MHV tree-level amplitudes in 0 ≤ N ≤ 4 gauge theories can be obtained directly from the known MHV amplitudes using the scalar graph approach of Cachazo, Svrcek and Witten. Generic amplitudes are given by sums of inequivalent scalar diagrams with MHV vertices. The novel feature of our method is that after the 'Feynman rules' for scalar diagrams are used, together with a particular choice of the reference spinor, no further helicity-spinor algebra is required to convert the results into a numerically usable form. Expressions for all relevant individual diagrams are free of singularities at generic phase space points, and amplitudes are manifestly Lorentz- (and gauge-) invariant. To illustrate the method, we derive expressions for n-point amplitudes with three negative helicities carried by fermions and/or gluons. We also write down a supersymmetric expression based on Nair's supervertex which gives rise to all such amplitudes in 0 ≤ N ≤ 4 gauge theories. (author)
A proposed physical analog for a quantum probability amplitude
Boyd, Jeffrey
What is the physical analog of a probability amplitude? All quantum mathematics, including quantum information, is built on amplitudes. Every other science uses probabilities; QM alone uses their square root. Why? This question has been asked for a century, but no one previously has proposed an answer. We will present cylindrical helices moving toward a particle source, which particles follow backwards. Consider Feynman's book QED. He speaks of amplitudes moving through space like the hand of a spinning clock. His hand is a complex vector. It traces a cylindrical helix in Cartesian space. The Theory of Elementary Waves changes direction so Feynman's clock faces move toward the particle source. Particles follow amplitudes (quantum waves) backwards. This contradicts wave particle duality. We will present empirical evidence that wave particle duality is wrong about the direction of particles versus waves. This involves a paradigm shift; which are always controversial. We believe that our model is the ONLY proposal ever made for the physical foundations of probability amplitudes. We will show that our ``probability amplitudes'' in physical nature form a Hilbert vector space with adjoints, an inner product and support both linear algebra and Dirac notation.
Energy Technology Data Exchange (ETDEWEB)
Saeki, T. [Japan National Oil Corporation, Tokyo (Japan). Technology Research Center
1996-10-01
For the seismic reflection method conducted on the ground surface, generator and geophone are set on the surface. The observed waveforms are affected by the ground surface and surface layer. Therefore, it is required for discussing physical properties of the deep underground to remove the influence of surface layer, preliminarily. For the surface consistent amplitude correction, properties of the generator and geophone were removed by assuming that the observed waveforms can be expressed by equations of convolution. This is a correction method to obtain records without affected by the surface conditions. In response to analysis and correction of waveforms, wavelet conversion was examined. Using the amplitude patterns after correction, the significant signal region, noise dominant region, and surface wave dominant region would be separated each other. Since the amplitude values after correction of values in the significant signal region have only small variation, a representative value can be given. This can be used for analyzing the surface consistent amplitude correction. Efficiency of the process can be enhanced by considering the change of frequency. 3 refs., 5 figs.
Some Media Relations Success Stories.
Sperbeck, John M.
1997-01-01
A panel of 29 extension faculty/staff members who work well with the media were interviewed to identify ways to improve their media relations. Reasons for working with the media, ways to develop relationships with media representatives, and suggestions for creating a more favorable climate for media relations in universities were noted. (JOW)
Directory of Open Access Journals (Sweden)
Denise Blasco
2014-10-01
relación entre la actividad turística y el empleo generado, tomando en cuenta las características propias de esta rama y sus efectos sobre el desarrollo de la economía regional. El presente trabajo pretende describir las principales características del empleo turístico vinculadas al principal atractivo de la región (El Calafate y su zona de influencia, y su aporte a la sustentabilidad de las comunidades involucradas.
John D. and Catherine T. MacArthur Foundation, 2012
2012-01-01
MacArthur launched the digital media and learning initiative in 2006 to explore how digital media are changing the way young people learn, socialize, communicate, and play. Since 2006, the Foundation has awarded grants totaling more than $100 million for research, development of innovative new technologies, new learning environments for youth,…
Roberts, Donald F.; Foehr, Ulla G.
2008-01-01
American youth are awash in media. They have television sets in their bedrooms, personal computers in their family rooms, and digital music players and cell phones in their backpacks. They spend more time with media than any single activity other than sleeping, with the average American eight- to eighteen-year-old reporting more than six hours of…
Creative Digital Media Practices
DEFF Research Database (Denmark)
Frølunde, Lisbeth
on collaboration (Benkler, 2006). The shift toward visual modes and digital media practices pose many pedagogical challenges for academics. I want to raise questions on how to teach “dialogically” with and through creative, digital media practices based on my plans for a course in Fall, 2011, where students...
Gabrick, Andrea; Dessoff, Alan
2002-01-01
Offers advice for college communications officers in dealing with the media. Tips include: "bring in the big guns", "play show and tell", expand the media circle, understand reporters' jobs and respect deadlines, "keep it real", "stay in touch", and "hedge your bets". (EV)
DEFF Research Database (Denmark)
Razmerita, Liana; Kirchner, Kathrin; Nabeth, Thierry
2014-01-01
avenues for a bottom-up approach incorporating a more personal knowledge management dimension, which could be synergized into collective knowledge using the social-collaborative dimension of social media. This article addresses the following questions: (1) How can social media support the management...
Riler, Robert
Designed for senior high school students, this one semester course focuses on four aspects of modern media: television, film, radio, and advertising. Each topic is worked into a weekly lesson plan format that stresses the active involvement of students in the learning process. The course outline contains lists of objectives and media materials…
Kempen, Petrus Cornelis
2011-01-01
The media can make or break a reputation. This being said, it seems to be essential for companies, governments and institutions to pay specific attention to corporate media management in their daily operations. However, this thesis shows that they often neglect to pay adequate attention to corporate
Radiocontrast media (its versions)
International Nuclear Information System (INIS)
Compositions, physical and chemical properties and the method of preparing radiocontrast media for using in X-ray diagnosis are presented. Radiocontrast media of bismuth oxyhalide and polyethylene, in which to improve radiocontrast zinc stearate and polyethelene of different densities are used, are descrabed
Building Social Media Connections
Ferriter, William N.; Ramsden, Jason T.; Sheninger, Eric C.
2012-01-01
Incorporating social media tools into your professional practices does not have to be intimidating as long as you are willing to tackle five action steps. It is far easier to articulate the strengths--and to imagine the possibilities--of social media spaces as tools for communication and professional development when you are actively using those…
Reconceptualizing (new media literacy
Directory of Open Access Journals (Sweden)
Petra Aczel
2014-02-01
Full Text Available This paper aims to introduce a theoretical-critical approach which shall revisit elements and cast light upon subsets of (new media literacy. It endeavours to draw community, spatial, procedural and aural literacy (auralacy into consideration, relating them to the complex of media literacy, striving to provide invigorating insights into its conceptual foundations and integrated perspectives for its pedagogy.
Tanaka, Sachiko Oda
1995-01-01
Describes the use of English in the media in Japan, focusing on the role and history of English-language newspapers, radio, and television programs, as well as the proliferation of English-language films shown in Japanese cinemas. Discusses the implications of English in the Japanese media. (20 references) (MDM)
Hewitt, Clifford A., Comp.; McKinstry, Herbert A., Comp.
This index provides a topical taxonomy of media which have been selected for their relevance in the teaching of materials science and engineering. The index is keyed to a matrix which matches topical and/or class material with six classifications of media: print, 16mm film, super 8 film, slide/tape, videotape, and other (including interactive…
Understanding social media logic
J. van Dijck; T. Poell
2013-01-01
Over the past decade, social media platforms have penetrated deeply into the mechanics of everyday life, affecting people's informal interactions, as well as institutional structures and professional routines. Far from being neutral platforms for everyone, social media have changed the conditions a
Directory of Open Access Journals (Sweden)
A Joshan
2000-07-01
Full Text Available Acute Otitis Media is a common problem of childhood. It is characterized by otalgia, fever, irritability, anorexia and vomiting or diarrhea. Diagnosis is most often made by pneumatic otoscopy. Acute Otitis Media is mostly caused by S.pneumonia or H.influenza there are sensitive to penicillins.
Nonionic radiographic contrast media
International Nuclear Information System (INIS)
The invention deals with nonionic radiographic contrast media. The new media, which are water soluble and have desirable low osmolality properties, are derivates of the 5-amino-2,4,6-triiodine-1,3-benzenecarboxylic acid-unity where the 5-aminonitrogen atom is a part of a 4-, 5- or 6-membered heterocyclic ring
Trolling new media: violent extremist groups recruiting through social media
Chang, Mark D.
2015-01-01
Approved for public release; distribution is unlimited With the advent and subsequent growth of several new media technologies, violent extremist groups have incorporated social media into recruiting strategies. How are violent extremist groups using social media for recruiting? This thesis explores several new media technologies—websites, blogs, social media, mobile phones, and online gaming—to determine if violent extremist groups rely on social media for recruiting. By comparing the com...
Media, Society, World: Social Theory and Digital Media Practice
Couldry, Nick
2012-01-01
Media are fundamental to our sense of living in a social world. Since the beginning of modernity, media have transformed the scale on which we act as social beings. And now in the era of digital media, media themselves are being transformed as platforms, content, and producers multiply. Yet the implications of social theory for understanding media and of media for rethinking social theory have been neglected; never before has it been more important to understand those implications. This ...
DEFF Research Database (Denmark)
Tække, Jesper
Weblogs are not only one of the newest technical media for communication, but also one of the most difficult to understand. Are weblogs a kind of mass medium, a personal medium like an online diary, or a medium that gives space for communities to grow? Or are weblogs a medium that enable all these...... possibilities depended on the actual use? This paper throws some light on what weblogs are by using the methodology of Media Sociography (Tække 2003, 2004a, 2004b and 2004c). Media Sociography is a strategy for analysing mediated social systems or in other words a strategy for describing the social in relation...... to the media it is based on. Theoretically seen it is inspired of two theoretical paradigms the Sociological Systems Theory of Niklas Luhmann and the Media Theory (also called the Toronto school). Empirically the paper primary draws on the literature about weblogs, which could be framed as CMC...
DEFF Research Database (Denmark)
Stohl, Cynthia; Etter, Michael; Banghart, Scott;
2015-01-01
Three global developments situate the context of this investigation: the increasing use of social media by organizations and their employees, the burgeoning presence of social media policies, and the heightened focus on corporate social responsibility (CSR). In this study the intersection...... of these trends is examined through a content analysis of 112 publicly available social media policies from the largest corporations in the world. The extent to which social media policies facilitate and/or constrain the communicative sensibilities and values associated with contemporary notions of CSR...... negotiation and participation in the social responsibilities of corporations. Moreover, policies generally enact organizational communication practices that are contrary to international CSR guidelines (e.g., the UN Global Compact and other international agreements). Findings suggest that social media...
DEFF Research Database (Denmark)
Etter, Michael; Colleoni, Elanor; Ravasi, Davide
directly to corporate performance and actions. Secondly, prominent reputation measurements couple stakeholders´ believes to reputation drivers through the use of predefined scales and items. We argue that with the rise of social media a company´s reputation has increasingly become autonomous from corporate...... actions, which demands a greater decoupling of stakeholders´ perceptions from corporate signals or actions in corporate reputation research. We develop the concept of social media reputation as the overall evaluation of a company presented in social media and present a new approach of measuring reputation...... based on social media data that accounts for the autonomy of stakeholder´s perception of a firm. We compare and contrast this novel social media reputation measure (SMRM) with traditional reputation measurements and find that SMRM is a valuable measurement to capture the autonomy of the stakeholders...
Role of the Ionosphere in the Generation of Large-Amplitude Ulf Waves at High Latitudes
Tulegenov, B.; Guido, T.; Streltsov, A. V.
2014-12-01
We present results from the statistical study of ULF waves detected by the fluxgate magnetometer in Gakona, Alaska during several experimental campaigns conducted at the High Frequency Active Auroral Research Program (HAARP) facility in years 2011-2013. We analyzed frequencies of ULF waves recorded during 26 strongly disturbed geomagnetic events (substorms) and compared them with frequencies of ULF waves detected during magnetically quite times. Our analysis demonstrates that the frequency of the waves carrying most of the power almost in all these events is less than 1 mHz. We also analyzed data from the ACE satellite, measuring parameters of the solar wind in the L1 Lagrangian point between Earth and Sun, and found that in several occasions there is a strong correlation between oscillations of the magnetic field in the solar wind and oscillations detected on the ground. We also found several cases when there is no correlation between signals detected on ACE and on the ground. This finding suggests that these frequencies correspond to the fundamental eigenfrequency of the coupled magnetosphere-ionosphere system. The low frequency of the oscillations is explained by the effect of the ionosphere, where the current is carried by ions through highly collisional media. The amplitude of these waves can reach significant magnitude when the system is driven by the external driver (for example, the solar wind) with this particular frequency. When the frequency of the driver does not match the frequency of the system, the waves still are observed, but their amplitudes are much smaller.
Puntos críticos sobre la reforma en Educación básica y media superior en México
Directory of Open Access Journals (Sweden)
Karina Rodríguez Cortés
2009-01-01
Full Text Available Uno de los varios problemas que enfrenta la reforma en el diseño curricular de los niveles de educación básica y media superior en México, es el relacionado con la mediación de los docentes para el trabajo educativo y la evaluación del desarrollo de competencias de los educandos. A lo anterior se suma, la gran cantidad de materiales generados al respecto, en los que la Secretaría de Educación Pública intenta exponer desde un discurso oficial: qué son las competencias y lo que éstas implican para el trabajo en el aula (dado que la institución no presenta con claridad a los docentes a qué tendencias mundiales en educación responde la modificación curricular.
Social media modeling and computing
Hoi, Steven CH; Boll, Susanne; Xu, Dong; Jin, Rong; King, Irwin
2011-01-01
Presents contributions from an international selection of preeminent experts in the field Discusses topics on social-media content analysis, and examines social-media system design and analysis Describes emerging applications of social media
International Nuclear Information System (INIS)
The initial objectives of this effort were to provide a hardware and software platform that can address the requirements for the accountability of classified removable electronic media and vault access logging. The Media Tracker system software assists classified media custodian in managing vault access logging and Media Tracking to prevent the inadvertent violation of rules or policies for the access to a restricted area and the movement and use of tracked items. The MediaTracker system includes the software tools to track and account for high consequence security assets and high value items. The overall benefits include: (1) real-time access to the disposition of all Classified Removable Electronic Media (CREM), (2) streamlined security procedures and requirements, (3) removal of ambiguity and managerial inconsistencies, (4) prevention of incidents that can and should be prevented, (5) alignment with the DOE's initiative to achieve improvements in security and facility operations through technology deployment, and (6) enhanced individual responsibility by providing a consistent method of dealing with daily responsibilities. In response to initiatives to enhance the control of classified removable electronic media (CREM), the Media Tracker software suite was developed, piloted and implemented at the Los Alamos National Laboratory beginning in July 2000. The Media Tracker software suite assists in the accountability and tracking of CREM and other high-value assets. One component of the MediaTracker software suite provides a Laboratory-approved media tracking system. Using commercial touch screen and bar code technology, the MediaTracker (MT) component of the MediaTracker software suite provides an efficient and effective means to meet current Laboratory requirements and provides new-engineered controls to help assure compliance with those requirements. It also establishes a computer infrastructure at vault entrances for vault access logging, and can accommodate
CLASSICAL MEDIA RELATIONS AND NEW MEDIA RELATIONS IN SPORT
Directory of Open Access Journals (Sweden)
Alexandru Lucian MIHAI
2014-06-01
Full Text Available Media relations in sport mean maintenance of networks and positive relationships with people in the media to obtain positive media exposure for a sport product (informal and formal information sessions with media representatives. Because of the pervasive influence the media has on marketing success, sport marketers must make concerted efforts to create a positive relationship between their sport event and the media. They may accomplish this by providing the media with press releases, having news conferences, having media-day events (in which the media are invited to interact with the players, coaches, and administrators, providing media guides for the respective sport events and so on. Each of these activities promotes active involvement from the media, which will subsequently contribute to relationship building with the community.
All tree-level amplitudes in massless QCD
Dixon, Lance J.; Henn, Johannes M.; Plefka, Jan; Schuster, Theodor
2011-01-01
We derive compact analytical formulae for all tree-level color-ordered gauge theory amplitudes involving any number of external gluons and up to four massless quarkanti-quark pairs. A general formula is presented based on the combinatorics of paths along a rooted tree and associated determinants. Explicit expressions are displayed for the next-to-maximally helicity violating (NMHV) and next-to-next-to-maximally helicity violating (NNMHV) gauge theory amplitudes. Our results are obtained by projecting the previously-found expressions for the super-amplitudes of the maximally supersymmetric super Yang-Mills theory ( mathcal{N} = 4 SYM) onto the relevant components yielding all gluon-gluino tree amplitudes in mathcal{N} = 4 SYM. We show how these results carry over to the corresponding QCD amplitudes, including massless quarks of different avors as well as a single electroweak vector boson. The public Mathematica package GGT is described, which encodes the results of this work and yields analytical formulae for all mathcal{N} = 4 SYM gluon-gluino trees. These in turn yield all QCD trees with up to four external arbitrary-flavored massless quark-anti-quark pairs.
All tree-level amplitudes in massless QCD
Dixon, Lance J; Plefka, Jan; Schuster, Theodor
2011-01-01
We derive compact analytical formulae for all tree-level color-ordered gauge theory amplitudes involving any number of external gluons and up to three massless quark-anti-quark pairs. A general formula is presented based on the combinatorics of paths along a rooted tree and associated determinants. Explicit expressions are displayed for the next-to-maximally helicity violating (NMHV) and next-to-next-to-maximally helicity violating (NNMHV) gauge theory amplitudes. Our results are obtained by projecting the previously-found expressions for the super-amplitudes of the maximally supersymmetric Yang-Mills theory (N=4 SYM) onto the relevant components yielding all gluon-gluino tree amplitudes in N=4 SYM. We show how these results carry over to the corresponding QCD amplitudes, including massless quarks of different flavors as well as a single electroweak vector boson. The public Mathematica package GGT is described, which encodes the results of this work and yields analytical formulae for all N=4 SYM gluon-gluino ...
All Tree-level Amplitudes in Massless QCD
Energy Technology Data Exchange (ETDEWEB)
Dixon, Lance J.; /CERN /SLAC; Henn, Johannes M.; Plefka, Jan; Schuster, Theodor; /Humboldt U., Berlin
2010-10-25
We derive compact analytical formulae for all tree-level color-ordered gauge theory amplitudes involving any number of external gluons and up to three massless quark-anti-quark pairs. A general formula is presented based on the combinatorics of paths along a rooted tree and associated determinants. Explicit expressions are displayed for the next-to-maximally helicity violating (NMHV) and next-to-next-to-maximally helicity violating (NNMHV) gauge theory amplitudes. Our results are obtained by projecting the previously-found expressions for the super-amplitudes of the maximally supersymmetric Yang-Mills theory (N = 4 SYM) onto the relevant components yielding all gluon-gluino tree amplitudes in N = 4 SYM. We show how these results carry over to the corresponding QCD amplitudes, including massless quarks of different flavors as well as a single electroweak vector boson. The public Mathematica package GGT is described, which encodes the results of this work and yields analytical formulae for all N = 4 SYM gluon-gluino trees. These in turn yield all QCD trees with up to four external arbitrary-flavored massless quark-anti-quark-pairs.
On the field theory expansion of superstring five point amplitudes
International Nuclear Information System (INIS)
A simple recursive expansion algorithm for the integrals of tree level superstring five point amplitudes in a flat background is given which reduces the expansion to simple symbol(ic) manipulations. This approach can be used for instance to prove the expansion is maximally transcendental to all orders and to verify several conjectures made in recent literature to high order. Closed string amplitudes follow from these open string results by the KLT relations. To obtain insight into these results in particular the maximal R-symmetry violating amplitudes (MRV) in type IIB superstring theory are studied. The obtained expansion of the open string amplitudes reduces the analysis for MRV amplitudes to the classification of completely symmetric polynomials of the external legs, up to momentum conservation. Using Molien's theorem as a counting tool this problem is solved by constructing an explicit nine element basis for this class. This theorem may be of wider interest: as is illustrated at higher points it can be used to calculate dimensions of polynomials of external momenta invariant under any finite group for in principle any number of legs, up to momentum conservation
Open & Closed vs. Pure Open String Disk Amplitudes
Stieberger, S
2009-01-01
We establish a relation between disk amplitudes involving N_o open and N_c closed strings and disk amplitudes with only N_o+2N_c open strings. This map, which represents a sort of generalized KLT relation on the disk, reveals important structures between open & closed and pure open string disk amplitudes: it relates couplings of brane and bulk string states to pure brane couplings. On the string world-sheet this becomes a non-trivial monodromy problem, which reduces the disk amplitude of N_o open and N_c closed strings to a sum of many color ordered partial subamplitudes of N_o+2N_c open strings. This sum can be further reduced to a sum over (N_o+2N_c-3)! subamplitudes of N=N_o+2N_c open strings only. Hence, the computation of disk amplitudes involving open and closed strings is reduced to computing these subamplitudes in the open string sector. In this sector we find a string theory generalization and proof of the Kleiss-Kuijf and Bern-Carrasco-Johanson relations: All order alpha' identities between open...
On the field theory expansion of superstring five point amplitudes
Energy Technology Data Exchange (ETDEWEB)
Boels, Rutger H., E-mail: rutger.boels@desy.de
2013-11-01
A simple recursive expansion algorithm for the integrals of tree level superstring five point amplitudes in a flat background is given which reduces the expansion to simple symbol(ic) manipulations. This approach can be used for instance to prove the expansion is maximally transcendental to all orders and to verify several conjectures made in recent literature to high order. Closed string amplitudes follow from these open string results by the KLT relations. To obtain insight into these results in particular the maximal R-symmetry violating amplitudes (MRV) in type IIB superstring theory are studied. The obtained expansion of the open string amplitudes reduces the analysis for MRV amplitudes to the classification of completely symmetric polynomials of the external legs, up to momentum conservation. Using Molien's theorem as a counting tool this problem is solved by constructing an explicit nine element basis for this class. This theorem may be of wider interest: as is illustrated at higher points it can be used to calculate dimensions of polynomials of external momenta invariant under any finite group for in principle any number of legs, up to momentum conservation.
On the field theory expansion of superstring five point amplitudes
Boels, Rutger H.
2013-11-01
A simple recursive expansion algorithm for the integrals of tree level superstring five point amplitudes in a flat background is given which reduces the expansion to simple symbol(ic) manipulations. This approach can be used for instance to prove the expansion is maximally transcendental to all orders and to verify several conjectures made in recent literature to high order. Closed string amplitudes follow from these open string results by the KLT relations. To obtain insight into these results in particular the maximal R-symmetry violating amplitudes (MRV) in type IIB superstring theory are studied. The obtained expansion of the open string amplitudes reduces the analysis for MRV amplitudes to the classification of completely symmetric polynomials of the external legs, up to momentum conservation. Using Molien's theorem as a counting tool this problem is solved by constructing an explicit nine element basis for this class. This theorem may be of wider interest: as is illustrated at higher points it can be used to calculate dimensions of polynomials of external momenta invariant under any finite group for in principle any number of legs, up to momentum conservation. In the closed (or mixed) case this follows after application of the Kawai-Lewellen-Tye [1] relations (or their analogons [2,3]).
Study of inelastic decay of amplitudes in 49V
International Nuclear Information System (INIS)
Inelastic decay amplitudes from d-wave resonances in 49V were obtained for 80 resonances in the proton energy range 2.2 to 3.1 MeV. With the 3 MV Van de Graaff accelerator and high resolution system at the Triangle Universities Nuclear Laboratory, an overall resolution of 350 eV was obtained. The experiment consisted of measurements of the angular distributions of the inelastically scattered protons and the subsequent deexcitation gamma rays. Forty five resonances were assigned J/sup π/ = 5/2+, while thirty five resonances were assigned 3/2+. The magnitudes of three inelastic decay amplitudes and the relative signs between these three amplitudes were determined. Large amplitude correlations were observed; the data are in the striking disagreement with the extreme statistical model. The present results provide the first explicit test of the multivariate reduced width amplitude distribution of Krieger and Porter; the agreement is excellent. The physical origin of these channel correlations has not yet been explained
The amplitude of solar oscillations using stellar techniques
Kjeldsen, Hans; Arentoft, Torben; Butler, R Paul; Dall, Thomas H; Karoff, Christoffer; Kiss, Laszlo L; Tinney, C G; Chaplin, William J
2008-01-01
The amplitudes of solar-like oscillations depend on the excitation and damping, both of which are controlled by convection. Comparing observations with theory should therefore improve our understanding of the underlying physics. However, theoretical models invariably compute oscillation amplitudes relative to the Sun, and it is therefore vital to have a good calibration of the solar amplitude using stellar techniques. We have used daytime spectra of the Sun, obtained with HARPS and UCLES, to measure the solar oscillations and made a detailed comparison with observations using the BiSON helioseismology instrument. We find that the mean solar amplitude measured using stellar techniques, averaged over one full solar cycle, is 18.7 +/- 0.7 cm/s for the strongest radial modes (l=0) and 25.2 +/- 0.9 cm/s for l=1. In addition, we use simulations to establish an equation that estimates the uncertainty of amplitude measurements that are made of other stars, given that the mode lifetime is known. Finally, we also give ...
International Nuclear Information System (INIS)
We study wave scattering in different nonlinear media possessing a natural forbidden band gap. In particular, we show the existence of a bistable behavior in media governed by the sine-Gordon equation (short pendular chain, Josephson junction array, quantum Hall bilayer), or the nonlinear Schroedinger equation (Kerr and Bragg media), in discrete and continuous models. These different media are submitted to periodic boundary conditions with a frequency in the forbidden band gap and an amplitude that determines their stability states. Indeed, for a sufficient amplitude (supra-transmission), the medium switches from reflector to transmitter, hence allowing the output signal to jump from evanescent to large values. We give a complete analytical description of the bistability that allows to understand the different stationary states observed and to predict the switch of one state to the other. (author)
Directory of Open Access Journals (Sweden)
Ali Arslan
2006-12-01
Full Text Available It is a reality that media play very substantial role in the production and social distribution of knowledge. İn addition to that, mass media provides the greatest communication opportunities to the people. Also, contemporary media provides very distinctive weapons to obtain power, wealth and prestige in the society. This study aims to analyse contemporary Turkish media. Turkey is one of the most rapidly developing and urbanising countries in the world. Parallel to this rapid development and urbanisation, Turkey has lived through a very important media revolution through out the 1990s. Several international and hundreds of local and national television channels, and more than a thousand radio stations have been broadcasting in contemporary Turkey. As in some other countries, the media are predominantly owned and controlled either by large business groups or the state who dominate economic and political power in Turkey. The Turkish media are financially dependent not only on the state but also on the private entrepreneurs who are the owners of large scale capital
Directory of Open Access Journals (Sweden)
Mohd. Shuhaimi Bin Haji Ishak
2012-05-01
Full Text Available The most important roles of the media are agenda-setting and representation. The media, particularly from the West, seems to feature Islam constantly in the negative light. The portrayal of the negative image of Islam takes place by constructing an image of Islam with terrorism, violence, extremism and antipathy to the West. A more recent phenomenon of Western media towards Islam is the fanning of ‘Islamophobia’ a form of concerted efforts directed to frighten the world of the hostility and enmity imposed by Islam. The Muslim world needs to respond to such striking negative representation of Islam. Contrary to what is generally perceived by the West, Islam in its real essence means ‘submission’ and ‘peace,’ a religion that calls for resignation to Allah and promotes and defends peace in the person. As much as the media can disrepute the general Muslim population and Islam, it can also restore and further inform the public of the true image of the religion. Thus, the primary aim of this paper is to explore the utilization of a variety of media to disseminate information and news to Muslims as well as non-Muslims on the true teachings of Islam. Through the media, the proper propagation and understanding of Islam can be enhanced by highlighting the universal values of the teachings of Islam. The media is a very important tool for effective communication and dissemination about Islam which the Muslim world could utilize.
Directory of Open Access Journals (Sweden)
Jelena Perovic
2015-12-01
Full Text Available Few countries in the world have introduced media education into their curriculums. Montenegro became one of them in 2009, when “media literacy” was introduced as an optional subject for 16 and 17 year old students of Gymnasium high schools. This article presents the findings of the first and only research conducted so far on media education in Montenegro. It is a national case study which examines the potential of media education to change the school culture and accelerate education system reform towards embracing the new digital education paradigm in the future. The focus is on the results of research conducted through in-depth interviews with media literacy teachers all over the country. Despite the many challenges, all teachers identify the potential of media education to strengthen some of the key competences of the students and to improve their motivation and academic performance. They also identify potential to change positively school culture by transforming teachers into “cultural mediators” (Morcellini, 2007 and by supporting the formation of a “participative culture” (Jenkins & Kelley, 2013 in schools. This research recommends focusing education reform on spreading the media education pedagogy to the entire curriculum in order to embrace the new digital education paradigm in the future.
DEFF Research Database (Denmark)
Plesner, Ursula; Gulbrandsen, Ib Tunby
2015-01-01
Despite current attention to the materiality of organizations and the performative role of tools, devices, artefacts and objects in processes of strategy-making, the impact of new media has not been thoroughly conceptualized in the strategy literature. We argue that new media challenge core...... assumptions in strategy about control, boundaries and choice. To understand their constitutive effects and the implications for strategy-making, it is necessary to develop a research agenda oriented towards understanding technological affordances – but not only in local practices. Due to vital characteristics...... of new media, this research agenda should be informed by a socio-material sensibility, network thinking and a longitudinal perspective. Keywords...
DEFF Research Database (Denmark)
Fausing, Bent
2014-01-01
The self and identity are not only issues connected to the selfies. They are connected to the development of media since the renaissance; this is the thesis of the following key-note. The subject, the self, is most clearly exposed in the face, and face and identity becomes important in the media...... continued throughout the coming centuries. The selfies is the latest invention to discover, explore, visualize and find the self of the subject. The following will therefore naturally focus on the self, the face where the self is most clearly expressed and seen, and the self-media, where the subject can...
DEFF Research Database (Denmark)
Media and information and communication technologies (ICTs) have in the past decades been placed firmly on the educational agenda, and will continue to maintain this position, not least as catalysts for educational change. This issue is reflected in the anthology as it aims to respond to the...... question of how the presence of media and ICT in and outside schools both change and qualify educational practice as well as how the cooperation between media, cultures, aesthetics and social relations affect and support new demands on education. The book represents different academic perspectives. The...
International Nuclear Information System (INIS)
The composition of culture media used for shoot proliferation and rooting has a tremendous influence on production costs. The type of culture vessel influences the efficiency of transfer during subculture and production of paraplegia's per unit area. Proper choice of media and containers can reduce the cost of micropropagation. The replacement of expensive imported vessels with re-usable glass jars and lids, alternatives to gelling agents, use of household sucrose, and some medium components can reduce costs of production Bulk making of media and storage as deep frozen stocks also reduces labour costs. (author)
Mohd. Shuhaimi Bin Haji Ishak; Sohirin Mohammad Solihin
2012-01-01
The most important roles of the media are agenda-setting and representation. The media, particularly from the West, seems to feature Islam constantly in the negative light. The portrayal of the negative image of Islam takes place by constructing an image of Islam with terrorism, violence, extremism and antipathy to the West. A more recent phenomenon of Western media towards Islam is the fanning of ‘Islamophobia’ a form of concerted efforts directed to frighten the world of the hostility and e...
Does social media reduce 'corporate media influence' on journalism?: The Case of Turkish Media
Ceren Sozeri
2011-01-01
McChesney described one of the biggest problem of journalism as “the journalists have any power to be autonomous from owners and advertisers” (2008:58). Most of media market have been dominated by a few media companies, furthermore a few media conglomerates who had expanded with merger and acquisitions transactions control the biggest part of the global media and entertainment industry. This concentration of media power and penetration of commercial interest in the news media has been seen as...
Gauge dependence in QED amplitudes in expanding de Sitter space
Nicolaevici, Nistor
2016-04-01
We consider first-order transition amplitudes in external fields in QED in the expanding de Sitter space and point out that they are gauge dependent quantities. We examine the gauge variations of the amplitudes assuming a decoupling of the interaction at large times, which allows to conclude that the source of the problem lies in the fact that the frequencies of the modes in the infinite future become independent of the comoving momenta. We show that a possibility to assure the gauge invariance of the external field amplitudes is to restrict to potentials which vanish sufficiently fast at infinite times, and briefly discuss a number of options in the face of the possible gauge invariance violation in the full interacting theory.
RECOLA: REcursive Computation of One-Loop Amplitudes
Actis, Stefano; Hofer, Lars; Lang, Jean-Nicolas; Scharf, Andreas; Uccirati, Sandro
2016-01-01
We present the Fortran95 program Recola for the perturbative computation of next-to-leading-order transition amplitudes in the Standard Model of particle physics. The code provides numerical results in the 't Hooft-Feynman gauge. It uses the complex-mass scheme and allows for a consistent isolation of resonant contributions. Dimensional regularization is employed for ultraviolet and infrared singularities, with the alternative possibility of treating collinear and soft singularities in mass regularization. Recola supports various renormalization schemes for the electromagnetic and a dynamical Nf-flavour scheme for the strong coupling constant. The calculation of next-to-leading-order squared amplitudes, summed over spin and colour, is supported as well as the computation of colour- and spin-correlated leading-order squared amplitudes needed in the dipole subtraction formalism.
Amplitude variations on the Extreme Adaptive Optics testbed
Energy Technology Data Exchange (ETDEWEB)
Evans, J; Thomas, S; Dillon, D; Gavel, D; Phillion, D; Macintosh, B
2007-08-14
High-contrast adaptive optics systems, such as those needed to image extrasolar planets, are known to require excellent wavefront control and diffraction suppression. At the Laboratory for Adaptive Optics on the Extreme Adaptive Optics testbed, we have already demonstrated wavefront control of better than 1 nm rms within controllable spatial frequencies. Corresponding contrast measurements, however, are limited by amplitude variations, including those introduced by the micro-electrical-mechanical-systems (MEMS) deformable mirror. Results from experimental measurements and wave optic simulations of amplitude variations on the ExAO testbed are presented. We find systematic intensity variations of about 2% rms, and intensity variations with the MEMS to be 6%. Some errors are introduced by phase and amplitude mixing because the MEMS is not conjugate to the pupil, but independent measurements of MEMS reflectivity suggest that some error is introduced by small non-uniformities in the reflectivity.
Berends-Giele recursion for double-color-ordered amplitudes
Mafra, Carlos R
2016-01-01
Tree-level double-color-ordered amplitudes are computed using Berends--Giele recursion relations applied to the bi-adjoint cubic scalar theory. The standard notion of Berends--Giele currents is generalized to double-currents and their recursions are derived from a perturbiner expansion of linearized fields that solve the non-linear field equations. Two applications are given. Firstly, we prove that the entries of the inverse KLT matrix are equal to Berends--Giele double-currents (and are therefore easy to compute). And secondly, a simple formula to generate tree-level BCJ-satisfying numerators for arbitrary multiplicity is proposed by evaluating the field-theory limit of tree-level string amplitudes for various color orderings using double-color-ordered amplitudes.
Simplifying one-loop amplitudes in superstring theory
Bianchi, Massimo; Consoli, Dario
2016-01-01
We show that 4-point vector boson one-loop amplitudes, computed in [1] in the RNS formalism, around vacuum configurations with open unoriented strings, preserving at least N=1 SUSY in D = 4, satisfy the correct supersymmetry Ward identities, in that they vanish for non MHV configurations (++++) and ( -+++). In the MHV case ( --++) we drastically simplify their expressions. We then study factorisation and the limiting IR and UV behaviours and find some unexpected results. In particular no massless poles are exposed at generic values of the modular parameter. Relying on the supersymmetric properties of our bosonic amplitudes, we extend them to manifestly supersymmetric super-amplitudes and compare our results with those obtained in the D = 4 hybrid formalism, pointing out difficulties in reconciling the two approaches for contributions from N=1,2 sectors.
Einstein-Yang-Mills from pure Yang-Mills amplitudes
Nandan, Dhritiman; Schlotterer, Oliver; Wen, Congkao
2016-01-01
We present new relations for scattering amplitudes of color ordered gluons and gravitons in Einstein-Yang-Mills theory. Tree-level amplitudes of arbitrary multiplicities and polarizations involving up to three gravitons and up to two color traces are reduced to partial amplitudes of pure Yang-Mills theory. In fact, the double-trace identities apply to Einstein-Yang-Mills extended by a dilaton and a B-field. Our results generalize recent work of Stieberger and Taylor for the single graviton case with a single color trace. As the derivation is made in the dimension-agnostic Cachazo-He-Yuan formalism, our results are valid for external bosons in any number of spacetime dimensions. Moreover, they generalize to the superamplitudes in theories with 16 supercharges.
On the saturation amplitude of the f-mode instability
Kastaun, Wolfgang; Kokkotas, Kostas D
2010-01-01
We investigate strong nonlinear damping effects which occur during high amplitude oscillations of neutron stars, and the gravitational waves they produce. For this, we use a general relativistic nonlinear hydrodynamics code in conjunction with a fixed spacetime (Cowling approximation) and a polytropic equation of state (EOS). Gravitational waves are estimated using the quadrupole formula. Our main interest are $l=m=2$ $f$-modes subject to the CFS (Chandrasekhar, Friedman, Schutz) instability, but we also investigate axisymmetric and quasi-radial modes. We study various models to determine the influence of rotation rate and EOS. We find that axisymmetric oscillations at high amplitudes are predominantly damped by shock formation, while the non-axisymmetric $f$-modes are mainly damped by wave breaking and, for rapidly rotating models, coupling to non-axisymmetric inertial modes. From the observed nonlinear damping, we derive upper limits for the saturation amplitude of CFS-unstable $f$-modes. Finally, we estima...
Heptagon amplitude in the multi-Regge regime
International Nuclear Information System (INIS)
As we have shown in previous work, the high energy limit of scattering amplitudes in N=4 supersymmetric Yang-Mills theory corresponds to the infrared limit of the 1-dimensional quantum integrable system that solves minimal area problems in AdS5. This insight can be developed into a systematic algorithm to compute the strong coupling limit of amplitudes in the multi-Regge regime through the solution of auxiliary Bethe Ansatz equations. We apply this procedure to compute the scattering amplitude for n=7 external gluons in different multi-Regge regions at infinite 't Hooft coupling. Our formulas are remarkably consistent with the expected form of 7-gluon Regge cut contributions in perturbative gauge theory. A full description of the general algorithm and a derivation of results is given in a forthcoming paper.
Amplitude of Accommodation and its Relation to Refractive Errors
Directory of Open Access Journals (Sweden)
Abraham Lekha
2005-01-01
Full Text Available Aims: To evaluate the relationship between amplitude of accommodation and refractive errors in the peri-presbyopic age group. Materials and Methods: Three hundred and sixteen right eyes of 316 consecutive patients in the age group 35-50 years who attended our outpatient clinic were studied. Emmetropes, hypermetropes and myopes with best-corrected visual acuity of 6/6 J1 in both eyes were included. The amplitude of accommodation (AA was calculated by measuring the near point of accommodation (NPA. In patients with more than ± 2 diopter sphere correction for distance, the NPA was also measured using appropriate soft contact lenses. Results: There was a statistically significant difference in AA between myopes and hypermetropes ( P P P P P P >0.5. Conclusion: Our study showed higher amplitude of accommodation among myopes between 35 and 44 years compared to emmetropes and hypermetropes
Amplitudes and Correlators to Ten Loops Using Simple, Graphical Bootstraps
Bourjaily, Jacob L; Tran, Vuong-Viet
2016-01-01
We introduce two new graphical-level relations among possible contributions to the four-point correlation function and scattering amplitude in planar, maximally supersymmetric Yang-Mills theory. When combined with the rung rule, these prove powerful enough to fully determine both functions through ten loops. This then also yields the full five-point amplitude to eight loops and the parity-even part to nine loops. We derive these rules, illustrate their applications, compare their relative strengths for fixing coefficients, and survey some of the features of the previously unknown nine and ten loop expressions. Explicit formulae for amplitudes and correlators through ten loops are available at: http://goo.gl/JH0yEc.
Berends-Giele recursion for double-color-ordered amplitudes
Mafra, Carlos R.
2016-07-01
Tree-level double-color-ordered amplitudes are computed using Berends-Giele recursion relations applied to the bi-adjoint cubic scalar theory. The standard notion of Berends-Giele currents is generalized to double-currents and their recursions are derived from a perturbiner expansion of linearized fields that solve the non-linear field equations. Two applications are given. Firstly, we prove that the entries of the inverse KLT matrix are equal to Berends-Giele double-currents (and are therefore easy to compute). And secondly, a simple formula to generate tree-level BCJ-satisfying numerators for arbitrary multiplicity is proposed by evaluating the field-theory limit of tree-level string amplitudes for various color orderings using double-color-ordered amplitudes.
General mechanism for amplitude death in coupled systems
Resmi, V.; Ambika, G.; Amritkar, R. E.
2011-10-01
We introduce a general mechanism for amplitude death in coupled synchronizable dynamical systems. It is known that when two systems are coupled directly, they can synchronize under suitable conditions. When an indirect feedback coupling through an environment or an external system is introduced in them, it is found to induce a tendency for antisynchronization. We show that, for sufficient strengths, these two competing effects can lead to amplitude death. We provide a general stability analysis that gives the threshold values for onset of amplitude death. We study in detail the nature of the transition to death in several specific cases and find that the transitions can be of two types—continuous and discontinuous. By choosing a variety of dynamics, for example, periodic, chaotic, hyperchaotic, and time-delay systems, we illustrate that this mechanism is quite general and works for different types of direct coupling, such as diffusive, replacement, and synaptic couplings, and for different damped dynamics of the environment.
Amplitudes of solar-like oscillations: a new scaling relation
DEFF Research Database (Denmark)
Kjeldsen, Hans; Bedding, Timothy R.
Solar-like oscillations are excited by near-surface convection and are being observed in growing numbers of stars using ground- and space-based telescopes. We have previously suggested an empirical scaling relation to predict their amplitudes. This relation has found widespread use but it predicts...... amplitudes in F-type stars that are higher than observed. Here we present a new scaling relation that is based on the postulate that the power in velocity fluctuations due to p-mode oscillations scales with stellar parameters in the same way as the power in velocity fluctuations due to granulation. The new...... relation includes a dependence on the damping rate via the mode lifetime and should be testable using observations from the CoRoT and Kepler missions. We also suggest scaling relations for the properties of the background power due to granulation and argue that both these and the amplitude relations should...
Collinear Limit of Scattering Amplitudes at Strong Coupling
Basso, Benjamin; Sever, Amit; Vieira, Pedro
2014-12-01
In this Letter, we consider the collinear limit of gluon scattering amplitudes in planar N =4 super-Yang-Mills theory at strong coupling. We argue that in this limit scattering amplitudes map into correlators of twist fields in the two dimensional nonlinear O (6 ) sigma model, similar to those appearing in recent studies of entanglement entropy. We provide evidence for this assertion by combining the intuition springing from the string world-sheet picture and the predictions coming from the operator product expansion series. One of the main implications of these considerations is that scattering amplitudes receive equally important contributions at strong coupling from both the minimal string area and its fluctuations in the sphere.
Convergence of transition amplitudes obtained with the Schwinger variational principle
Rodríguez, V D
2016-01-01
An exactly solvable time-dependent quantum mechanical problem is employed to study the convergence properties of transition amplitudes calculated by using the Schwinger variational principle. A detailed comparison between the amplitudes approximated by the perturbative series and by their associated Schwinger variational principles is performed. The much better performance obtained by the variational principle is documented through different case studies. For a given order of the Schwinger principle, it is observed that the transition amplitudes do not converge to the exact one for large perturbations. The latter is true even though large combinations of unperturbed states with constant coefficients are taken as trial wave functions. As a matter of fact, it is shown that the improvement of the method comes from using better trial wave functions and increasing the order of the Schwinger principle employed.
Fringe-free holographic measurements of large-amplitude vibrations.
Joud, F; Verpillat, F; Laloë, F; Atlan, M; Hare, J; Gross, M
2009-12-01
In the measurement of the amplitude of vibration of objects, holographic imaging techniques usually involve fringe counting; because of the limited resolution of the images, measurements of large amplitudes are not accessible. We demonstrate a technique that suppresses the necessity of fringe counting--frequency sideband imaging--where the order of the sideband is considered a marker of the amplitude. The measurement is completely local: no comparison with another reference point on the object is necessary. It involves a sharp variation of a signal, which makes it robust against perturbations. The method is demonstrated in an experiment made with a vibrating clarinet reed; phase modulations as large as 1000 rad have been measured. PMID:19953166
Root-mean-square pulse-amplitude-to-number converters
International Nuclear Information System (INIS)
The amplitude dispersion of pulses from gas-discharge and other detectors of ionizing radiation is determined by the sum of the analog additive noise and is proportional to the amplitude of the Poisson component. Losses of energy resolution or overexpenditure of channels are reduced by conversion of pulse amplitude to code by comparison of the peak value with a periodic parabolic voltage. The described converter has a scale that is linear with respect to atomic number and provides a constancy peak width that is acceptable for a digital spectrum filter with constant parameters. With 256 channels, the dead time is less than or equal to 25.6 microseconds and the error of the root-mean-square scale is less than 0.1% of the instantaneous value. The described converter has undergone prolonged testing under laboratory and field conditions in conjunction with an AMA-8 portable x-ray spectrometer and has shown sufficiently high metrological characteristics
Amplitude Analysis of the B+- ->phi K*(892)+- Decay
Aubert, B; Boutigny, D; Karyotakis, Yu; Lees, J P; Poireau, V; Prudent, X; Tisserand, V; Zghiche, A; Garra Tico, J; Graugès-Pous, E; López, L; Palano, A; Eigen, G; Stugu, B; Sun, L; Abrams, G S; Battaglia, M; Brown, D N; Button-Shafer, J; Cahn, R N; Groysman, Y; Jacobsen, R G; Kadyk, J A; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Lopes-Pegna, D; Lynch, G; Mir, L M; Orimoto, T J; Ronan, M T; Tackmann, K; Wenzel, W A; Del Amo-Sánchez, P; Hawkes, C M; Watson, A T; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Schröder, T; Steinke, M; Walker, D; Asgeirsson, D J; Çuhadar-Dönszelmann, T; Fulsom, B G; Hearty, C; Mattison, T S; McKenna, J A; Khan, A; Saleem, M; Teodorescu, L; Blinov, V E; Bukin, A D; Druzhinin, V P; Golubev, V B; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Todyshev, K Yu; Bondioli, M; Curry, S; Eschrich, I; Kirkby, D; Lankford, A J; Lund, P; Mandelkern, M A; Martin, E C; Stoker, D P; Abachi, S; Buchanan, C; Foulkes, S D; Gary, J W; Liu, F; Long, O; Shen, B C; Zhang, L; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Cunha, A; Dahmes, B; Hong, T M; Kovalskyi, D; Richman, J D; Beck, T W; Eisner, A M; Flacco, C J; Heusch, C A; Kroseberg, J; Lockman, W S; Schalk, T; Schumm, B A; Seiden, A; Williams, D C; Wilson, M G; Winstrom, L O; Chen, E; Cheng, C H; Fang, F; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Andreassen, R; Mancinelli, G; Meadows, B T; Mishra, K; Sokoloff, M D; Blanc, F; Bloom, P C; Chen, S; Ford, W T; Hirschauer, J F; Kreisel, A; Nagel, M; Nauenberg, U; Olivas, A; Smith, J G; Ulmer, K A; Wagner, S R; Zhang, J; Gabareen, A M; Soffer, A; Toki, W H; Wilson, R J; Winklmeier, F; Zeng, Q; Altenburg, D D; Feltresi, E; Hauke, A; Jasper, H; Merkel, J; Petzold, A; Spaan, B; Wacker, K; Brandt, T; Klose, V; Kobel, M J; Lacker, H M; Mader, W F; Nogowski, R; Schubert, J; Schubert, K R; Schwierz, R; Sundermann, J E; Volk, A; Bernard, D; Bonneaud, G R; Latour, E; Lombardo, V; Thiebaux, C; Verderi, M; Clark, P J; Gradl, W; Muheim, F; Playfer, S; Robertson, A I; Xie, Y; Andreotti, M; Bettoni, D; Bozzi, C; Calabrese, R; Cecchi, A; Cibinetto, G; Franchini, P; Luppi, E; Negrini, M; Petrella, A; Piemontese, L; Prencipe, E; Santoro, V; Anulli, F; Baldini-Ferroli, R; Calcaterra, A; De Sangro, R; Finocchiaro, G; Pacetti, S; Patteri, P; Peruzzi, I M; Piccolo, M; Rama, M; Zallo, A; Buzzo, A; Contri, R; Lo Vetere, M; Macri, M M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Chaisanguanthum, K S; Morii, M; Wu, J; Dubitzky, R S; Marks, J; Schenk, S; Uwer, U; Bard, D J; Dauncey, P D; Flack, R L; Nash, J A; Nikolich, M B; Panduro-Vazquez, W; Tibbetts, M; Behera, P K; Chai, X; Charles, M J; Mallik, U; Meyer, N T; Ziegler, V; Cochran, J; Crawley, H B; Dong, L; Eyges, V; Meyer, W T; Prell, S; Rosenberg, E I; Rubin, A E; Gao, Y Y; Gritsan, A V; Guo, Z J; Lae, C K; Denig, A G; Fritsch, M; Schott, G; Arnaud, N; Bequilleux, J; Davier, M; Grosdidier, G; Höcker, A; Lepeltier, V; Le Diberder, F R; Lutz, A M; Pruvot, S; Rodier, S; Roudeau, P; Schune, M H; Serrano, J; Sordini, V; Stocchi, A; Wang, W F; Wormser, G; Lange, D J; Wright, D M; Bingham, I; Chavez, C A; Forster, I J; Fry, J R; Gabathuler, E; Gamet, R; Hutchcroft, D E; Payne, D J; Schofield, K C; Touramanis, C; Bevan, A J; George, K A; Di Lodovico, F; Menges, W; Sacco, R; Cowan, G; Flächer, H U; Hopkins, D A; Paramesvaran, S; Salvatore, F; Wren, A C; Brown, D N; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Chia, Y M; Edgar, C L; Lafferty, G D; West, T J; Yi, J I; Anderson, J; Chen, C; Jawahery, A; Roberts, D A; Simi, G; Tuggle, J M; Blaylock, G; Dallapiccola, C; Hertzbach, S S; Li, X; Moore, T B; Salvati, E; Saremi, S; Cowan, R; Dujmic, D; Fisher, P H; Koeneke, K; Sciolla, G; Sekula, S J; Spitznagel, M; Taylor, F; Yamamoto, R K; Zhao, M; Zheng, Y; Mclachlin, S E; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L; Eschenburg, V; Godang, R; Kroeger, R; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Côté, D; Simard, M; Taras, P; Viaud, F B; Nicholson, H; De Nardo, Gallieno; Fabozzi, F; Lista, L; Monorchio, D; Sciacca, C; Baak, M A; Raven, G; Snoek, H L; Jessop, C P; LoSecco, J M; Benelli, G; Corwin, L A; Honscheid, K; Kagan, H; Kass, R; Morris, J P; Rahimi, A M; Regensburger, J J; Wong, Q K; Blount, N L; Brau, J E; Frey, R; Igonkina, O; Kolb, J A; Lu, M; Rahmat, R; Sinev, N B; Strom, D; Strube, J; Torrence, E; Gagliardi, N; Gaz, A; Margoni, M; Morandin, M; Pompili, A; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Voci, C; Ben-Haim, E; Briand, H; Calderini, G; Chauveau, J; David, P; Del Buono, L; La Vaissière, C de; Hamon, O; Leruste, P; Malcles, J; Ocariz, J; Pérez, A; Gladney, L; Biasini, M; Covarelli, R; Manoni, E; Angelini, C; Batignani, G; Bettarini, S; Carpinelli, M; Cenci, R; Cervelli, A; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Mazur, M A; Morganti, M; Neri, N; Paoloni, E; Rizzo, G; Walsh, J J; Haire, M; Biesiada, J; Elmer, P; Lau, Y P; Lü, C; Olsen, J; Smith, A J S; Telnov, A V; Baracchini, E; Bellini, F; Cavoto, G; D'Orazio, A; Del Re, D; Di Marco, E; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Jackson, P D; Li Gioi, L; Mazzoni, M A; Morganti, S; Piredda, G; Polci, F; Renga, F; Voena, C; Ebert, M; Hartmann, T; Schröder, H; Waldi, R; Adye, T; Castelli, G; Franek, B; Olaiya, E O; Ricciardi, S; Röthel, W; Wilson, F F; Aleksan, R; Emery, S; Escalier, M; Gaidot, A; Ganzhur, S F; Hamel de Monchenault, G; Kozanecki, W; Vasseur, G; Yéche, C; Zito, M; Chen, X R; Liu, H; Park, W; Purohit, M V; Wilson, J R; Allen, M T; Aston, D; Bartoldus, R; Bechtle, P; Berger, N; Claus, R; Coleman, J P; Convery, M R; Dingfelder, J C; Dorfan, J; Dubois-Felsmann, G P; Dunwoodie, W; Field, R C; Glanzman, T; Gowdy, S J; Graham, M T; Grenier, P; Hast, C; Hrynóva, T; Innes, W R; Kaminski, J; Kelsey, M H; Kim, H; Kim, P; Kocian, M L; Leith, D W G S; Li, S; Luitz, S; Lüth, V; Lynch, H L; MacFarlane, D B; Marsiske, H; Messner, R; Müller, D R; O'Grady, C P; Ofte, I; Perazzo, A; Perl, M; Pulliam, T; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Snyder, A; Stelzer, J; Su, D; Sullivan, M K; Suzuki, K; Swain, S K; Thompson, J M; Vavra, J; Van Bakel, N; Wagner, A P; Weaver, M; Wisniewski, W J; Wittgen, M; Wright, D H; Yarritu, A K; Yi, K; Young, C C; Burchat, P R; Edwards, A J; Majewski, S A; Petersen, B A; Wilden, L; Ahmed, S; Alam, M S; Bula, R; Ernst, J A; Jain, V; Pan, B; Saeed, M A; Wappler, F R; Zain, S B; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Ritchie, J L; Ruland, A M; Schilling, C J; Schwitters, R F; Izen, J M; Lou, X C; Ye, S; Bianchi, F; Gallo, F; Gamba, D; Pelliccioni, M; Bomben, M; Bosisio, L; Cartaro, C; Cossutti, F; Della Ricca, G; Lanceri, L; Vitale, L; Azzolini, V; Lopez-March, N; Martínez-Vidal, F; Milanes, D A; Oyanguren, A; Albert, J; Banerjee, Sw; Bhuyan, B; Hamano, K; Kowalewski, R V; Nugent, I M; Roney, J M; Sobie, R J; Back, J J; Harrison, P F; Ilic, J; Latham, T E; Mohanty, G B; Pappagallo, M; Band, H R; Chen, X; Dasu, S; Flood, K T; Hollar, J J; Kutter, P E; Pan, Y; Pierini, M; Prepost, R; Wu, S L; Neal, H
2007-01-01
We perform an amplitude analysis of B+- -> phi(1020) K*(892)+- decay with a sample of about 384 million BBbar pairs recorded with the BABAR detector. Overall, twelve parameters are measured, including the fractions of longitudinal f_L and parity-odd transverse f_perp amplitudes, branching fraction, strong phases, and six parameters sensitive to CP-violation. We use the dependence on the Kpi invariant mass of the interference between the JP=1- and 0+ Kpi components to resolve the discrete ambiguity in the determination of the strong and weak phases. Our measurements of f_L=0.49+-0.05+-0.03, f_perp=0.21+-0.05+-0.02, and the strong phases point to the presence of a substantial helicity-plus amplitude from a presently unknown source.