1,042 research outputs found
Analysis of Mathieu Equation Stable Solutions in the First Zone of Stability
No full textAbstractThe paper presents the results of a homogeneous Mathieu equation studies. Mathieu equation solutions are oscillations, modulated in amplitude and frequency. In the computational experiments we found dependences of the given oscillations on the ratio of the coefficients. These dependences are shown in graphs that can be used for an approximate estimation of the Mathieu equation solutions without integration
Pensar las escalas para pensar las luchas: Autor: Mathieu UHEL
No full textA través de un título sugerente, “pensar las escalas para pensar las luchas”, Mathieu Uhel entreteje la construcción teórico-crítica del concepto escala, generada por la geografía radical anglosajona de finales del siglo XX, con la necesidad/utilidad práctica de la escala para concienciar las luchas sociales. El artículo cumple un doble propósito: por un lado, delinear los elementos de lectura sobre el concepto escala; y, con ello, promover la atención de esta problemática en las luchas contemporáneas. En un primer apartado, Uhel ubica las discusiones académicas en torno a la escala, como herramienta metodológica útil para comprender la complejidad de las sociedades capitalistas; en el segundo apartado, el autor avanza la exposición en torno al contexto de la dimensión escalar del imperialismo capitalista; finalmente, el autor se centra en el rol de la actividad política a escala nacional en la tensa relación entre las imposiciones del capital y la lucha social.Por meio de um título sugestivo, “pensando escalas para pensar lutas”, Mathieu Uhel entrelaça a construção teórico-crítica do conceito de escala, gerado pela geografia radical anglo-saxônica do final do século XX, com a necessidade / utilidade prática escala para aumentar a consciência das lutas sociais. O artigo tem um duplo propósito: por um lado, delinear os elementos de leitura sobre o conceito de escala; e, com isso, promover atenção a esse problema nas lutas contemporâneas. Na primeira seção, Uhel localiza as discussões acadêmicas em torno da escala, como uma ferramenta metodológica útil para compreender a complexidade das sociedades capitalistas; na segunda seção, o autor avança a exposição em torno do contexto da dimensão escalar do imperialismo capitalista; por fim, o autor enfoca o papel da atividade política em escala nacional na tensa relação entre as imposições do capital e a luta social.Mathieu Uhel\u27s suggestive title, “Thinking about scales to think about struggles”, he interweaves the theoretical-critical construction of concept scale, generated by radical Anglo-Saxon geography in the late 20th century, with it´s practical utility to social struggles. The article serves two purposes: on the one hand, Uhel locates academic discussion around scale; and, with this, he promotes attention to this problem in contemporary struggles. In the first section, Uhel locates academic discussions around scale, as a useful methodological tool to understand the complexity of capitalist societies; in the second section, the author advances the argument around the context of the scalar dimension of capitalist imperialism; finally, the author focuses on the role of political activity on a national scale in the tense relationship between the impositions of capital and the social movement
Mathieu Ichou, Les Enfants d’immigrés à l’école
No full textIt is common to hear in the fields of educational and immigration sociology that on average, the children of immigrants do not perform as well in school as children of native-born parents. Mathieu Ichou offers an innovative sociological analysis on a topic that is heavily exploited by political and media discourse, and subject to much scientific controversy. The author takes distance from the homogenized vision of a “second generation” of students who have totally failed academically, and rep..
L'impatto dell'attività tintoria sull'ambiente. Firenze alla fine del Medioevo
No full textThe author aims to examine and categorize the range of dyeings materials used in the Florentine wool and silk textile industries in the late Middle Ages, focusing mainly on those produced within the regional space in order to evaluate the impact of the Florentine dyeing activity on the natural environment and the productive landscape of the Tuscan countryside. In particular, the author establishes a line of demarcation between cultivated and uncultivated resources in order to verify which constitutes an indication of the level of industrial development of medieval textile production. This further focuses on how the transition from the exploitation of wild resources to the exploitation of cultivated resources could reflect a greater degree of economic integration between the countryside and the city and contribute to the formation of a regional economic space
Dynamique de relaxation dans des boîtes quantiques GaN/AlN : étude par photoluminescence et transmission différentielle pompe-sonde résolues en temps
No full textDans cette étude, nous avons approfondi la dynamique complexe de relaxation des paires électron-trou au sein de boîtes quantiques GaN/AlN à l’état de l’art. Grâce à l’utilisation combinée de différentes techniques d’optique ultra-rapide, nous avons étudié la dynamique des paires électron-trou depuis leur photocréation dans la couche de mouillage jusqu’à leur recombinaison à partir des états discrets des boîtes, sur des échelles de temps allant de quelques centaines de femtosecondes à quelques nanosecondes. La photoluminescence résolue en temps a montré que l’effet Stark quantique confiné est le principal facteur responsable de la dépendance des durées de vie radiatives en fonction de la taille de la boîte. A partir de la forme des déclins, qui s’écartait de la simple fonction exponentielle attendue, nous avons extrait des informations pertinentes sur la structure de l’échantillon comme, par exemple, la présence d’un état sombre influençant la dynamique via une capture réversible des porteurs. De plus, différentes morphologies de boîtes ont été identifiées dans un autre échantillon, chacune présentant de temps de recombinaison spécifique. Notre modèle analytique a également confirmé l’absence d’écrantage du champ électrique interne par les porteurs photo-injectés pendant la recombinaison. Les expériences de pompe-sonde dégénérées et non-dégénérées ont révélé une efficacité des processus de thermalisation et de capture dans les boîtes rarement observée dans d’autres systèmes semi-conducteurs III-V. Ces découvertes soulignent les propriétés uniques du GaN et des conditions expérimentales spécifiques employées. L’évolution du temps de montée du signal de transmission différentielle avec l’énergie des photons indique une saturation des états en dessous de l’énergie de l’impulsion de sonde. Parallèlement, la dynamique de relaxation est régie à la fois par les durées de vie radiatives et la densité des états accessibles à plus basse énergie. Plus précisément, cette dynamique ralentit lorsque l’énergie de sonde est résonnante avec l’état fondamental de la boîte ou l’un de ses états excités. En revanche, des processus tels que l’effet Auger, et potentiellement un écrantage du champ électrique interne, accélèrent cette dynamique, en particulier à des densités de porteurs élevées.In this study, we investigated the complex relaxation dynamics of electron-hole pairs within state-of-the-art GaN/AlN quantum dots. Thanks to the combined use of different ultrafast optics techniques, we have studied the dynamics of electron-hole pairs from their photocreation in the wetting layer to their recombination from the discrete states of the dots, on timescales ranging from a few hundred femtoseconds to a few nanoseconds. Time-resolved photoluminescence showed that the quantum confined Stark effect is the main factor responsible for the dependence of radiative lifetimes on dot size. From the shape of the decays, which deviated from the expected simple exponential function, we extracted relevant information about the structure of the sample, highlighting the reversible capture of carriers in a dark state. Additionally, different dot morphologies were identified in another sample, each exhibiting specific recombination times. Our analytical model also confirmed the absence of screening of the internal electric field by the photo-injected carriers during recombination. Degenerate and non-degenerate pump-probe experiments have revealed an efficiency of thermalization and capture processes in dots rarely seen in other III-V semiconductor systems. These findings highlight the unique properties of GaN and the specific experimental conditions employed. The evolution of the rise time of the differential transmission signal with the energy of the photons indicates a saturation of the states below the energy of the probe pulse. At the same time, the relaxation dynamics is governed by both the radiative lifetimes and the density of accessible states at lower energies. More precisely, this dynamic slows down when the probe energy is resonant with the ground state of the dot or one of its excited states. On the other hand, processes such as the Auger effect, and potentially screening of the internal electric field, accelerate this dynamics, especially at high carrier densities
Mathieu de Fossey: su visión del mundo indígena mexicano
No full textThroughout these pages the author shows how Mathieu de Fossey perceived that it was not easy to make indigenous communities fit within the mould of the nation-state which, being based on the liberal and egualitarian ideology, was against the recognition of special regimes, such as those that created a peculiar status for the native population of the American territory during the period of Spanish colonial domination
Mathieu de Fossey: su visión del mundo indígena mexicano
No full textÀ travers ces pages, l’auteur montre comment Mathieu de Fossey avait perçu la difficulté d’insérer le monde des communautés indigènes dans le moule d’un État national qui, accroché à une idéologie libérale égalitaire, refusait d’établir des régimes spéciaux comparables à ceux qui, durant la domination espagnole, avaient reconnu un statut particulier aux populations natives du continent américain.A través de estas páginas se muestra cómo Mathieu de Fossey percibió el difícil acoplamiento del mundo de las comunidades indígenas en el molde de un Estado nacional que, por estar sustentado en la ideología liberal igualitaria, era contrario al reconocimiento de regímenes especiales como los que, durante la dominación española, habían establecido un status peculiar para los aborígenes del territorio americano.Throughout these pages the author shows how Mathieu de Fossey perceived that it was not easy to make indigenous communities fit within the mould of the nation-state which, being based on the liberal and egualitarian ideology, was against the recognition of special regimes, such as those that created a peculiar status for the native population of the American territory during the period of Spanish colonial domination
Investigation of documents persistency on the Web
No full text@inproceedings{CI-Lancieri-2004-2, author = {Lancieri, Luigi and Lecouvey, Mathieu and Glasse, Veronique}, title = {Investigation of documents persistency on the Web}, booktitle = {International conference E-Society 2004 (ES2004), IADIS}, year = {2004}, address = {Spain} }International audienc
Development and test of a universal FPGA-based Arc Detector for accelerating cavities at the facility for Antiproton and Ion Research FAIR [10.08.2011]
No full textOnTEAM metadata: GDSID: DOC-2011-Nov-83; Attribute ID: LIBRARY-thesis_ma-2011-001; Title: [GSI Ma 2011-01] Development and test of a universal FPGA-based Arc Detector for accelerating cavities at the facility for Antiproton and Ion Research FAIR [10.08.2011]; Author(s): Omet, Mathieu; Corporate author(s): ; Publication date: 20111116; Creator: manton; Creation date: 16.11.2011 16:02:19; Change date: 16.11.2011 16:44:09; Access: Welt; Attribute type: Text.Thesis.MA; Directory path: ['GSI Publications', 'GSI as Publisher']; Attribute path: ['Infrastructure', 'Library and Documentation', 'thesis_ma', 'Added in 2011']; File name(s): ['DOC-2011-Nov-83-1.pdf']; File title(s): ['']; File access: ['GSI-intern'
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