• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1278
  • 617
  • 518
  • 241
  • 177
  • 113
  • 66
  • 52
  • 49
  • 31
  • 28
  • 26
  • 24
  • 14
  • 13
  • Tagged with
  • 3723
  • 254
  • 234
  • 206
  • 174
  • 166
  • 165
  • 156
  • 146
  • 146
  • 144
  • 143
  • 134
  • 125
  • 120
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
181

Erratum: Turning Double-Torus Links Inside Out (Journal of Knot Theory and Its Ramifications (1999) 8:6 (789-798))

Lane, S., Norwood, H., Norwood, R. 01 January 2013 (has links)
No description available.
182

Approche fonctorielle et combinatoire de la propérade des algèbres double Poisson / A functorial and combinatorial approach to double Poisson algebras and their properad

Leray, Johan 05 December 2017 (has links)
On construit et étudie la généralisation des algèbres double Poisson décalées à toute catégorie monoïdale symétrique additive. On s’intéresse notamment aux algèbres double Poisson linéaires et quadratiques. Dans un second temps, on étudie la koszulité des propérades DLie et DPois = As ⮽c DLie qui encodent respectivement les algèbres double Lie et les algèbres doubles Poisson. On associe à chacune de ces propérades, un S-module muni d’une structure de monoïde pour un nouveau produit monoïdal dit de composition connexe : on appelle de tels monoïdes protopérades. On montre notamment l’existence, pour toutS-module, d’une protopérade libre associée et l’on explicite la combinatoire sous-jacente en terme de briques et de murs. On définit une adjonction bar-cobar, une dualité de Koszul et une notion de base PBW pour les protopérades. On présente également une tentative de théorème PBW à la Hoffbeck pour les protopérades, de laquelle on déduit la koszulité de la diopérade associée à la propérade DLie. / We construct and study the generalization of shifted double Poisson algebras to all additive symmetric monoidal categories. We are especially interested in linear and quadratic double Poisson algebras. We then study the koszulity of the properads DLie and DPois = As ⮽c DLie which encode double Lie algebras and double Poisson algebras respectively. We associate to each, a S-module with a monoidal structure for a new monoïdal product call the connected composition product : we call such monoids protoperads. We show, for any S-module, the existence of the associated free protoperad and we make explicit the underlying combinatorics. We define a bar-cobar adjunction, the notion of Koszul duality and PBW bases for protoperads. We present an attempt of prove a PBW theorem à la Hoffbeck for protoperads, and prove the koszulity of the dioperad associated to the properad DLie.
183

Functional relations among certain double polylogarithms and their character analogues

TSUMURA, Hirofumi, MATSUMOTO, Kohji January 2008 (has links)
No description available.
184

The Effects of Spin-Orbit Coupling on Gravitational Wave Uncertainties

Wainwright, C. L. 27 April 2007 (has links)
Paper discusses the expected uncertainty of orbital parameters of binary stars as measured by the space-based gravitational wave observatory LISA (Laser Interferometer Space Antenna) and how the inclusion of spin in the model of the binary stars affects the uncertainty. The uncertainties are found by calculating the received gravitational wave from a binary pair and then performing a linear least-squares parameter estimation. The case of a 1500 solar mass black hole that is 20 years from coalescing with a 1000 solar mass black hole--both of which are 50 x 10^6 light years away--is analyzed, and the results show that the inclusion of spin has a negligible effect upon the angular resolution of LISA but can increase the accuracy in mass and distance measurements by factors of 15 and 65, respectively.
185

Energy- and angle-resolved infrared-laser-assisted xuv single- and two-photon double ionization of helium

Liu, Aihua January 1900 (has links)
Doctor of Philosophy / Department of Physics / Uwe Thumm / Although the latest and most powerful supercomputer today, Tianhe-2 in China, can finish 33.86 quadrillion floating-point operations per second (www.top500.org), it is still a big challenge to simulate the simplest few-electron system - the helium atom - a threebody system with one nucleus and two electrons. Within the fixed-nucleus approximation and time-dependent close coupling (TDCC) approach, we developed software to solve the time-dependent Schrödinger equation (TDSE) accurately, implementing the finite-element discrete-variable representation (FE-DVR) scheme. The general idea of the method is to expand the wave functions in the eigenvectors of the angular momentum operator, which further transform the six-dimensional TDSE to a set of infinite two-dimensional coupled equations. Although there are infinitely many coupled equations, they can be truncated to a finite number of equations by applying selection rules and physical requirements, and solved with our current computational resources. By numerically solving the TDSE in full dimensionality, we investigate the double photoionization of helium atoms in external fields. In co-planar emission geometry with and without the presence of a comparatively weak infrared (IR) laser pulse, we discuss the double ionization (DI) dynamics of helium atoms irradiated by ultrashort pulses of extreme ultraviolet (XUV) laser light. We first investigate the degree of electronic correlation by correlated photoelectron angular distributions for two-photon double ionization (TPDI) of helium atoms in the sequential and non-sequential DI regime. We quantify sequential and non-sequential contributions to TPDI driven by an XUV pulse with central photon energy hw[subscript]xuv near the sequential DI threshold. If the spectral width of the XUV pulse is broad enough, both the sequntial (hw[subscript]xuv > 54.4 eV) and non-sequential (hw[subscript]xuv < 54.4 eV) channels are open. Therefore, the sequential and non-sequential DI mechanisms are difficult to distinguish. By tracking the DI asymmetry in joint photoelectron angular distributions, we introduce the forward-backward-emission asymmetry as a measure that allows the distinction of sequential and non-sequential contributions. Specifically, for hw[subscript]xuv = 50 eV pulses with a sine-squared temporal profile, we find that the sequential DI contribution is the largest at a pulse length of 650 as (1 as = 10[superscript]−18 s), due to competing temporal and spectral constraints. In addition, we validate a simple heuristic expression for the sequential DI contribution in comparison with ab initio calculations. We then investigate the influence of the laser field on the DI of helium by a single XUV pulse. For IR-laser-assisted single-XUV-photon DI our joint angular distributions show that the IR-laser field enhances back-to-back electron emission and induces a characteristic splitting in the angular distribution for electrons that are emitted symmetrically relative to the identical linear polarization directions of the XUV and IR pulse. These IR-pulse-induced changes in photoelectron angular distributions are (i) imposed by different symmetry constraints for XUV-pulse-only and laser-assisted XUV-photon DI, (ii) robust over a large range of energy sharing between the emitted electrons, and (iii) consistent with the transfer of discrete IR-photon momenta to both photoelectrons from the assisting IR-laser field. While selection-rule forbidden at equal energy sharing, for increasingly unequal energy sharing we find back-to-back emission to become more likely and to compete with symmetric emission. To obtain a high level of accuracy, accurate quantum-mechanical calculations of three Coulomb interacting particales exposed to an intense XUV and weak IR field are at the limit of current computational power. Any direct extension (such as strong laser-field intensity, elliptically-polarized field, and laser-induced DI) of our approach to more complicated systems appears to be currently out of reach. At the end of this thesis, we give suggestions on how to improve the efficiency of TDSE calculations for simulations of these complicated many-photon processes.
186

Simplification and Octavation in Double Bass Performance: An Overview of Historical and Contemporary Practices

Shih, Wen-Ling 05 1900 (has links)
Two important performance practices in the modern orchestral performance are discussed in this document: simplification and octavation. Due to the differing opinions and common practices which bass players have around these two performance practices, simplification and octavation have become two of the most complex issues faced by orchestral sections. The first part of the document will provide a brief history of simplification and octavation. The second part of the document will offer recommendation for double bass orchestral practice in the 21st century and examine key works of the bass repertoire in which simplification and octavation occur. The research and practice of leading pedagogues and major orchestral players and the solutions they have developed to reduce the discrepancy inherent within section playing will be discussed. This document will propose several empirical solutions to major excerpts in the bass repertoire, demonstrating how it is to achieve the most uniformed playing, and offer applicable and suggestive guidelines for contemporary orchestral double bass performers.
187

Interpretation and Execution of Chords on the Double Bass from Select Movements of the Bach Cello Suites

Chen, Der-Shiuan 08 1900 (has links)
The Bach Cello Suites have become widely transcribed and studied on the double bass. They have also become essential teaching material as most US orchestra auditions demand solo Bach for bass auditions. Transcribing the chords in Bach Cello Suites presents many difficulties on the bass because of the different tuning of our instrument (cello in 5ths; double bass in 4ths). There is no unified solution to all the problems presented in chord playing at this time. The purpose of this project, therefore is to give bass players solutions to the problems by looking at historical interpretation of chords, technical execution of the chords on cello and bass, tonal and resonance considerations and fingering solutions. The chords chosen represent the most common and most difficult to transcribe to the double bass from the Cello Suites.
188

Improved integration of female refugees? : - An evaluation of the Establishment reform

Wennemo Lanninger, Alma January 2016 (has links)
It may take several years for a refugee in Sweden to establish on the labor market. The slow establishment is particularly problematic for female refugees. Compared to men, low-skilled women and women with young children experience major disadvantages. In Sweden, refugees were offered a voluntary program with measures to ease the integration into the labor market. On December 1, 2010, the enacting of the so-called Establishment reform, which was carried out in order to speed up the refugees’ labor market entry, changed that program. Newly arrived refugees were then offered participation in an Establishment program at the Public Employment service instead of an Introduction program offered by the municipalities. This thesis provides an evaluation of the Establishment reform. The aim is to analyze the employment rates two and three years after enrollment in the program. The applied approach is to compare the outcome for the refugees participating in the Introduction program with the outcome for the refugees participating in the Establishment program, while controlling for important observables. This is possible by using Swedish register data on all immigrants given residence permit in Sweden 2009-2011. The findings from the evaluation provide evidence that the Establishment reform has had a small but significant effect on the probability of being employed. Those participating in the Establishment program showed higher employment rates compared to participants in the previous Introduction program. This association was evident for both women and men. Among low-skilled women, co-resident mothers, and women with young children, no significant increase in the probability of being employed was observed. It thereby seems like the reform at large has had a positive effect but that more effort is needed for those with the initially largest disadvantages.
189

Binary pulsar PSR1913+16 as a laboratory for gravitomagnetism and structure of neutron stars

龔碧平, Gong, Biping. January 2001 (has links)
published_or_final_version / Physics / Doctoral / Doctor of Philosophy
190

Contribution à la caractérisation de protéines impliquées dans la transduction des signaux : C3VS, le récepteur de la TSH et SHIP2

Jacobs, Christine 04 June 2004 (has links)
Dans le thyrocyte normal, la TSH active une voie dépendante de l’adénylyl cyclase/AMPc, qui représente l’une des trois voies mitogéniques de la thyroïde. La cascade de signalisation de la TSH diffère des deux autres voies dans sa capacité à induire à la fois la prolifération et la différenciation, comprenant la synthèse et la sécrétion des hormones thyroïdiennes. Identifier les acteurs de cette cascade de signalisation, ainsi que les interactions entre effecteurs, est donc très important pour la compréhension de la fonction de la cellule thyroïdienne. C’est dans ce cadre que s’insère notre travail au cours duquel nous nous sommes intéressés au récepteur de la TSH ainsi qu’à une protéine récemment identifiée dans le laboratoire et dont l’expression est modulée en réponse à la TSH dans la thyroïde : C3VS. C3VS est une protéine qui présente six motifs ankyrine et une tirette à leucine et dont la fonction était inconnue à l'époque. Dans un premier temps, nous avons contribué à l’obtention de la séquence codante complète du C3VS de chien, puis, l'identification des partenaires d'une protéine pouvant aider à caractériser sa fonction, nous nous sommes proposé de rechercher les partenaires potentiels de la région N-terminale de C3VS par la méthode double-hybride. Nous avons étudié la distribution tissulaire et la régulation par la TSH de différents partenaires isolés. Parmi eux, SUG1, une ATPase du protéasome 26S, a été étudiée plus avant mais l’interaction n’a pas pu être confirmée par "GST-pulldown assay". Simultanément, une remise en question de la position de la méthionine initiale de C3VS, couplée à une impossibilité d’exprimer la protéine en cellules COS par transfection mettait en péril le travail. En l’absence de plus d’arguments fonctionnels permettant d’orienter l’étude des positifs, cette partie du travail a été suspendue au profit de notre étude sur le récepteur de la TSH. L'activation de cascades différentes dans le thyrocyte humain et canin pouvant être due à l'action de protéines intracellulaires, nous avons tenté de rechercher par double-hybride des partenaires protéiques autres que les protéines G pour le récepteur de la TSH. Nous avons ainsi identifié PRA1 mais nous n’avons pas pu confirmer l'interaction entre les deux protéines par "GST-pulldown assay". Pour tenter de comprendre le rôle de cette interaction, nous avons réalisé des essais fonctionnels en transfectant des cellules pour évaluer l'implication de PRA1 sur la synthèse d’AMPc. Ces expériences ne nous ont pas permis de montrer un rôle pour PRA1 au niveau de la cascade, mais en revanche, nous avons mis en évidence le fait que la co-transfection de deux ADNc codant pour des protéines membranaires sature la machinerie de traduction et diminue l'expression du RTSH. Dans une deuxième partie de notre travail, nous avons étudié la 5-phosphatase SHIP2, dont l’implication dans la cascade de réponse à l’insuline était suggérée, entre autres, par le travail d’Isabelle Vandenbroere qui avait montré l’interaction de cette protéine avec CAP et c-Cbl. Nous avons développé au laboratoire la culture de la lignée pré-adipocytaire 3T3-L1 et étudié la localisation de SHIP2 au niveau des rafts de ces cellules. Nous avons montré que SHIP2 n’y est pas recrutée. CAP et c-Cbl ne semblent pas non plus y être recrutées, tandis que nous y avons détecté le récepteur de l'insuline. La localisation de différentes protéines impliquées dans la cascade de l'insuline dans les rafts est une question controversée à l’heure actuelle et notre étude montre que l’implication fonctionnelle de SHIP2 dans la cascade de l'insuline n'est probablement pas dépendante des rafts.

Page generated in 0.0249 seconds