111 research outputs found
Active X-ray optics for the next generation of X-ray space telescopes
No full textDescribed within is the design, manufacture, metrology and X-ray testing of an active X-ray
prototype intended for the next generation of X-ray telescopes. One of the challenges faced by
the X-ray telescope community is how to combine high resolution and high sensitivity into one
system, as weight limitations place constraints on the optics that can be launched. Therefore the
mandate of the active X-ray prototype is to provide high sensitivity through the ability of the optics
to be nested and to deliver high angular resolution through the active control of the optic’s form.
Piezoelectric unimorph actuators provide the active component: it is intended that they will correct
for figure errors within the optic and therefore increase the angular resolution capability.
The prototype’s design is based upon an ellipsoidal segment which provides point-to-point
focussing of an X-ray source. The prototype itself is composed of an electroformed nickel optic
where the non-reflective surface is populated with 30 piezoelectric actuators and it is the production
of the prototype that is the core of the presented research. Metrology of the actuators’ influence
functions is presented and highlight the prototype’s ability to deform its optic surface by microns.
In addition, the measured influence functions are compared against finite element models and a
distinct similarity between the functions is observed.
The prototype was tested at an X-ray beamline facility in November 2008 and the results
showed the prototype’s ability to correct the optic to achieve an improved angular resolution: from
0.786 arc-minutes to 0.686 arc-minutes in terms of full width half maximum. Finally, difficulties
in the manufacture of the prototype and X-ray testing shall be presented alongside future work in
conclusion to this thesis
A cognitive-stylistic analysis of the early works of John McGahern
No full textThe early works of Irish author John McGahern (1934-2006), The Barracks and The Dark, are the result of dividing the original work into two different novels after he did not succeed in getting it published. Although a significant amount of literary analysis has already been carried out on both novels, a large gap arises when it comes to a proper linguistic approach. The present dissertation aims at filling that gap. The starting point of this doctoral thesis are the previous literary approaches by scholars such as Guy, Liddy, Maher and O’Connell. The literary insights offered by these authors qualify themselves as a valuable basis upon which to build up a cognitive-stylistic approach to the figurative language employed by John McGahern. The main objectives of this dissertation are three, namely, (i) to unearth the cognitive processes hidden in the figurative language employed by the author, and describe the controversial metaphors and metonymies which serve as a mechanism to denounce the puritan society in the Republic of Ireland; (ii) to analyze the complex techniques of characterization employed by McGahern to build up round characters in both stories as notorious examples of social by-products of their time, and how they cope with the darkest ideological sides of a deeply conservative and religious rural sociocultural context, and (iii) to dig out the choice of the linguistic constructions deployed by the Irish novelist in an effort to convey his message. The general view of functional and cognitive space offered in the works by Butler and Gonzálvez-García serves as an invaluable scientific framework to substantiate the analysis of the two novels. Out of this general view, the models applied to varying degrees are (i) Systemic Functional Grammar, (ii) Cognitive Grammar, (iii) Construction Grammar(s), together with (iv) Cognitive Stylistics, or (v) Poetics. The application of these cognitive fields needed further substantiation. This is the point where the crossroads of literature and linguistics lies, in the form of fresh and state-of-the-art cognitive literary approaches by scholars such as Burke and Troscianko, Polvinen, Kukkonen, Fludernik, Carney, Gibbs, Oatley, Bergs, Gerrig and Mumper, Pirlet and Wirag, or Hartner, among others. Within the vast realm of Conceptual Metaphor Theory (henceforth CMT), and by drawing upon the work of authors like Lakoff, Kövecses, Ruiz de Mendoza Ibáñez, Peña-Cervel, Steen, Fauconnier and Turner, Sullivan and Gonzálvez-García among some others, the basic notions of image-schemas, conceptual domains, idealized cognitive models, semantic frames, mental spaces and coercion are explained and applied to the study of the conceptual metaphors in the most relevant passages from both novels. Approaches offered by scholars like Barcelona, Radden, Thornburg and Panther, Blanco-Carrión, Hernández-Gomáriz, Ruiz de Mendoza Ibáñez, as well as Brdar and Szabó, to mention just a few, are invoked to study the metonymies that emerge from the selected excerpts. Other related tropes, such as hyperbole (Claridge, Peña-Cervel and Ruiz de Mendoza Ibáñez) are also approached in the light of conceptual metaphors and metonymies, due to their closeness in cognitive processes. The analysis of the larger stretches of text from both novels is mainly tackled from the perspective of Cognitive Grammar, by appealing to authors such as Langacker, Stockwell, Harrison, Yuan, Nuttal, and some others. The tools and notions in the light of which Cognitive Grammar is applied to both novels are specificity, prominence, profiling, perspective, stance, ambience and windows of attention. This is carried out by paying close attention to the linguistic constructions—particular attention is given to conditional and modal constructions as stance enactors—as well as lexical choices such as different adjectival and nominal constructions—useful as ambience enactors. The characters, their worldview and mindstyle are deconstructed and studied by drawing upon the insights by Culpeper, Semino, Fauconnier and Turner’s Blending Theory and Emmot’s Split Selves. This is also consistent with the passages where McGahern’s ideological postulates clash with the predominant puritan principles that pervade the two novels. Talmy’s fictive motion proves a useful technique in which the roles of Light and Nature are relevant to convey McGahern’s message. Both novels are flooded with passages in wan, feeble lights, and nature qualifies itself as a prison, or even an enemy. Finally, the windows of attention proposed by authors such as Harrison, or Browse serve as an invaluable light in which actions and participants within the frames and domains of ANGER, LUST, DEATH, FAITH or PRISON are given salience. Resumen: Las primeras obras del autor irlandés (1934-2006), The Barracks y The Dark, son el resultado de dividir la obra original en dos novelas diferentes, tras no haber tenido éxito en su intento de publicarla. Aunque la cantidad de análisis literario sobre las dos novelas ha sido significativa, lo cierto es que, a nivel de un enfoque lingüístico, el vacío que se abre es grande. La presente disertación tiene como objetivo principal llenar ese vacío. El punto de partida de esta tesis doctoral son los enfoques literarios previos realizados por académicos tales como Guy, Liddy, Maher y O’Connell. Las aportaciones literarias ofrecidas por estos autores conforman una base sólida sobre la cual construir un enfoque cognitivo-estilístico del lenguaje figurativo empleado por John McGahern. Los principales objetivos de esta tesis doctoral son tres: (i) sacar a la luz los procesos cognitivos ocultos en el lenguaje figurativo empleado por el autor, y describir las controvertidas metáforas y metonimias que sirven de mecanismo para denunciar el puritanismo en la República de Irlanda; (ii) analizar las complejastécnicas de caracterización utilizadas por John McGahern para construir personajes redondos en ambas historias como ejemplos manifiestos de productos de la sociedad de su tiempo, y cómo se desenvuelven con los matices ideológicos más oscuros de un contexto rural profundamente conservador y religioso, y (iii) extraer la elección de construcciones lingüísticas desplegadas por el novelista irlandés en su esfuerzo por hacer llegar su mensaje a los lectores. La visión general del espacio funcional y cognitivo ofrecido en el trabajo de Butler y Gonzálvez-García sirve como valiosa estructura científica para fundamentar el análisis de ambas novelas. De esta visión general, los modelos aplicados, con distinto nivel de profundidad son (i) la Gramática Sistémico Funcional, (ii) la Gramática Cognitiva, (iii) la(s) Gramática(s) de Construcciones, junto con (iv) la Estilística o (v) Poética Cognitiva. La aplicación de estos campos del cognitivismo necesita una fundamentación adicional. Es aquí entonces donde surge el punto de encuentro entre la lingüística y la literatura, en forma de recientes y vanguardistas enfoques cognitivo-literarios a cargo de académicos como Burke & Troscianko, Polvinen, Kukkonen, Fludernik, Carney, Gibbs, Oatley, Bergs, Gerrig y Mumper, Pirlet y Wirag, o Hartner, entre otros.
Dentro del vasto terreno de la Teoría de la Metáfora Conceptual (en adelante, CMT), y recurriendo al trabajo de autores como Lakoff, Kövecses, Ruiz de Mendoza Ibáñez, Peña-Cervel, Stee, Fauconnier y Turner, Sullivan y Gonzálvez-García, entre algunos otros, nociones básicas como esquemas de imagen, dominios conceptuales, modelos cognitivos idealizados, marcos semánticos, espacios mentales y coerción son explicados y aplicados al estudio de las metáforas conceptuales en los pasajes más relevantes de ambas novelas. Los enfoques ofrecidos por académicos como Barcelona, Radden, Thornburg y Panther, Blanco-Carrión, Hernández-Gomáriz, Ruiz de Mendoza Ibáñez, así como Brdar y Szabó, por mencionar tan solo unos pocos, serán invocados para estudiar las metonimias que emergen de los fragmentos seleccionados. Otras figuras relacionadas, como la hipérbole (Claridge, Peña-Cervel y Ruiz de Mendoza Ibáñez) son también estudiados a la luz de la metáfora y la metonimia conceptuales, debido a la cercanía de sus procesos cognitivos. El análisis de extensos fragmentos de texto de ambas novelas será también enfocado desde la perspectiva de la Gramática Cognitiva, recurriendo a autores como Langacker, Stockwell, Harrison, Yuan, Nuttal, y algunos otros. Las herramientas y nociones a la luz de las cuales la Gramática Cognitiva es aplicada a ambas novelas son (i) especificidad, (ii) prominencia, (iii) perfil, (iv) perspectiva, (v) posición, (vi) ambiente y (vii) ventanas de atención. Esto se lleva a cabo prestando minuciosa atención a las construcciones lingüísticas—con especial énfasis en las construcciones condicionales y modales, como activadores de posición—además de léxicas, tales como construcciones nominales y adjetivales—relevantes como activadores de ambiente. Los personajes, su visión del mundo, y su estilo mental son deconstruidos y estudiados recurriendo a la percepción de autores como Culpeper, Semino, la Teoría de la Integración Conceptual de Fauconnier y Turner, y el Yo Dividido, de Emmot. Esto muestra consistencia con los pasajes en los cuales los postulados ideológicos de McGahern chocan con los principios puritanos predominantes que impregnan las dos novelas. El movimiento ficticio de Talmy constituye una técnica muy útil en la cual el papel de la Luz, la Naturaleza muestran su relevancia para transmitir el mensaje de McGahern. Ambas novelas están inundadas de luces tenues y débiles, mientras que la naturaleza se constituye como una prisión en sí misma, o incluso como un enemigo Finalmente, las ventanas de atención, propuestas por autores como Harrison, o Browse sirven de inestimable recurso bajo el cual las acciones y los participantes dentro de los marcos y dominios semánticos de RABIA, LUJURIA, MUERTE, FÉ, o PRISIÓN son dotados de prominencia
Measurement of high-Q (2) charged current deep inelastic scattering cross sections with a longitudinally polarised positron beam at HERA
No full textMeasurements of the cross sections for charged current deep inelastic scattering in e+p collisions with a longitudinally polarised positron beam are presented. The measurements are based on a data sample with an integrated luminosity of 132 pb-1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is presented at positive and negative values of the longitudinal polarisation of the positron beams. The single-differential cross-sections dσ/dQ2, dσ/dx and dσ/dy are presented for Q2>200 GeV2. The reduced cross-section σ̃ is presented in the kinematic range 200<Q2<60000 GeV2 and 0.006<x<0.562. The measurements agree well with the predictions of the Standard Model. The results are used to determine a lower limit on the mass of a hypothetical right-handed W boson. © 2010 The Author(s)
Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA
No full textA combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy √s= 318 Gev where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6 % for the most precise points. The combined data cover the range 2.5 < Q 2 < 200 GeV 2 in photon virtuality, 0.00035 < xP < 0.09 in proton fractional momentum loss, 0.09 <{pipe}t{pipe}< 0.55 GeV 2 in squared four-momentum transfer at the proton vertex and 0.0018 < β <0.816 in β=x/xP, where x is the Bjorken scaling variable. © 2012 The Author(s).0H1 and ZEUS CollaborationsSCOPUS: ar.jinfo:eu-repo/semantics/publishe
"Magia en al-Andalus: Rasā’il Ijwān al-Ṣafā’, Rutbat al-Ḥakīm y Gāyat al-Ḥakīm (Picatrix)"
No full textThis article is concerned with the introduction of the Rasa’il Ikhwan al-Safa’ to al-Andalus, and the implication this question has for the history of Arabic science and philosophy. More specifically, it focuses on the impact of the encyclopaedia of the Brethren of Purity on the Rutbat al-Hakim and the Ghayat al- Hakim, two important works of the literature of al-Andalus in the field of occult sciences. The article revisits the issue of authorship and chronology of the three works, highlighting the fact that the corpus of the Rasa’il is the product of a historically long process of composition and confirming with some new clues the identification of the author of the Rutba and the Ghaya with Maslama al-Qurtubi (d. 964). The textual comparison of these three works and, in particular, the study of the still unedited Rutba enables one to identify Maslama al-Qurtubi as the genuine transmitter of the Ikhwanian corpus to al-Andalus
An annotated bibliography of tax compliance and tax compliance costs
No full textAn annotated bibliography of tax compliance and tax compliance costs.tax; tax compliance; compliance costs; bibliography; tax evasion; tax avoidance; auditing; tax simplification
A search for resonance decays to lepton + jet at HERA and limits on leptoquarks
No full textA search for narrow-width resonances that decay into electron+jet or neutrino+jet has been performed with the ZEUS detector at the DESY ep collider HERA operating at center-of- mass energies of 300 and 318 GeV. An integrated e(+)p luminosity of 114.8 pb(-1) and e(-)p luminosity of 16.7 pb(-1) were used. No evidence for any resonance was found. Limits were derived on the Yukawa coupling lambda as a function of the mass of a hypothetical resonance that has arbitrary decay branching ratios into eq or nuq. These limits also apply to squarks predicted by R-parity-violating supersymmetry. Limits for the production of leptoquarks described by the Buchmuller-Ruckl- Wyler model were also derived for masses up to 400 GeV. For lambda=0.1, leptoquark masses up to 290 GeV are excluded
Measurement of deeply virtual Compton scattering at HERA
No full textThe cross-section for deeply virtual Compton scattering in the reaction ep → egammap has been measured with the ZEUS detector at HERA using integrated luminosities of 95.0 pb(-1) of e(+) p and 16.7 pb(-1) of e(-) p collisions. Differential cross-sections are presented as a function of the exchanged- photon virtuality, Q(2), and the centre-of-mass energy, W, of the gamma*p system in the region 5 lt Q(2) lt 100 GeV2 and 40 lt W lt 140 GeV. The measured cross-sections rise steeply with increasing W. The measurements are compared to QCD-based calculations. (C) 2003 Elsevier B.V. All rights reserve
Measurement of the open-charm contribution to the diffractive proton structure function
No full textProduction of D*+/-(2010) mesons in diffractive deep inelastic scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 82 pb(-1). Diffractive events were identified by the presence of a large rapidity gap in the final state. Differential cross sections have been measured in the kinematic region 1.5 lt Q(2) lt 200 GeV2 0.02 lt y lt 0.7, x(P) lt 0.035, beta lt 0.8, P-T (D*+/-) gt 1.5 GeV and \eta(D*+/-)\ lt 1.5. The measured cross sections are compared to theoretical predictions. The results are presented in terms of the open- charm contribution to the diffractive proton structure function. The data demonstrate a strong sensitivity to the diffractive parton densities
Jet production in charged current deep inelastic e+ p scattering at HERA
No full textThe production rates and substructure of jets have been studied in charged current deep inelastic e(+)p scattering for Q(2) gt 200 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 110.5 pb(-1). Inclusive jet cross sections are presented for jets with transverse energies E-T(jet) gt 14 GeV and pseudorapidities in the range -1 lt η(jet) lt 2. Dijet cross sections are presented for events with a jet having E- T(jet) gt 14 Gev and a second jet having E-T(jet) gt 5 GeV. Measurements of the mean events with a jet having E, gt 14 GeV and a second jet having E, subjet multiplicity, (n(sbj)), of the inclusive jet sample are presented. Predictions based on parton-shower Monte Carlo models and next-to-leading-order QCD calculations are compared to the measurements. The value of alpha(s) (M-z), determined from (n(sbj)) at y(cut) = 10(-2) for jets with 25 lt E-T(jet) lt 119 GeV, is α(s) (M-z) = 0. 1202 +/- 0.0052 (stat.)(-0.0019)(+0.0060) (syst.)(- 0.0053)(+0.0065) (th.). The mean subjet multiplicity as a function of Q(2) is found to be consistent with that measured in NC DlS
- …
