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  • 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.
291

Contribution au développement de l'utilisation des fibres naturelles dans les composites structuraux. Étude du comportement d'un composite Lin/Epoxy lors d'un vieillissement hygrothermique / Contribution to the development of natural fibers' use in structural composites. Study of a Flax / Epoxy composite’s behavior when exposed to hygrothermal ageing

Cadu, Thomas 22 October 2018 (has links)
Les composites bio-sourcés et notamment à base de fibres de lin connaissent depuis quelques années un regain d’intérêt, particulièrement dans les domaines des transports, de la mobilité et des loisirs. En effet, le faible coût énergétique et environnemental de la fibre de lin lui confère un avantage face à la fibre de verre, tout en la concurrençant en termes de propriétés mécaniques spécifiques. Cependant le comportement à long terme en environnement humide des composites à base de fibres de lin reste méconnu et constitue un frein à leur utilisation à plus grande échelle. Les objectifs de ces travaux sont de donner des clés pour produire un composite lin/époxy de haute qualité et de contribuer à l’amélioration de la connaissance de la durabilité de ces matériaux. Tout d’abord, l’influence de nombreux paramètres de mise en œuvre [(i) le pré conditionnement des renforts, (ii) la température de cuisson, (iii) la pression appliquée lors de la cuisson, (iv) la vitesse de refroidissement, (v) la température de sortie de la plaque, (vi) la température de post-cuisson et (vii) la durée de post-cuisson] sur les propriétés mécaniques des composites a été étudiée afin d’obtenir des matériaux de haute qualité. Une méthode de vieillissement « réaliste » a ensuite été développée afin d’étudier la durabilité de ce type de composites en présence d’eau. Des cycles de vieillissements hygrothermiques ont ainsi été menés en laboratoire sur des éprouvettes de composite, de résine et des faisceaux de fibres. Puis des analyses multi-échelles basées sur des caractérisations physico-chimiques, microstructurales et morphologiques du composite lin/époxy au cours de ce vieillissement ont permis de mieux comprendre les mécanismes responsables de leurs évolutions de propriétés mécaniques longitudinales et transverses au cours du temps. / In recent years there is renewed interest for bio-sourced composites, including those based on flax fibers, and especially in the field of transport, mobility and leisure. In fact, the lower energy cost and environmental impact of flax fiber give it an advantage over glass fiber, while competing with its specific mechanical properties. However, flax fibers based composites long-term behavior remains poorly known in damp environments and constitutes an obstacle to a wider use. This work aims to provide adapted parameters to produce a high-grade flax/epoxy composite and to contribute to improve the durability knowledge of these materials. First, the influence of many processing parameters [(i) conditioning of the reinforcements, (ii) curing temperature, (iii) curing pressure, (iv) cooling speed, (v) exit temperature, (vi) post curing temperature and (vii) post curing duration] on the composites’ mechanical properties have been studied in order to manufacture high-grade materials. Then a “realistic” ageing method has been developed to study the durability of this kind of composites when exposed to water. Thus cyclic hygrothermal ageing has been applied to composite, resin and fiber bundles in the laboratory. Then multi-scale analyzes based on physicochemical, microstructural and morphological characterizations of the flax/epoxy composites helped to better understand the mechanisms responsible for the longitudinal and transverse mechanical properties’ evolutions over time.
292

Characterization of lin-42/period transcriptional regulation by the Ikaros/hunchback-family transcription factor ZTF-16 in Caenorhabditis elegans

Meisel, Kacey Danielle 03 June 2013 (has links)
The gene lin-42 is an ortholog of the mammalian period gene, a component of the circadian pathway that converts environmental stimuli into behavioral and physiological outputs over 24 hours. Mammalian period also regulates adult stem cell differentiation, although this function is poorly understood. The structure, function and expression of lin-42 are all similar to period. Therefore, we are studying lin-42 regulation and function during C. elegans larval development as a model for understanding period control of mammalian stem/progenitor cell development. Previous work has shown that ZTF-16 is a regulator of lin-42 transcription. The lin-42 locus encodes three isoforms, and we have characterized lin-42 isoform specific regulation by ZTF-16 through phenotypic assays and analysis of transcriptional reporter strains. Our data show that ZTF-16 regulates the cyclic expression of lin-42A and lin-42B during larval development. However, ztf-16 is not expressed during the adult stage and does not regulate lin-42C, which is expressed only in adults and may be responsible for the circadian functions of lin-42. We also show that ztf-16 reduction-of-function mutations phenocopy loss-of- function phenotypes of the lin-42A/B isoforms. Finally, we have found that deletion of a putative ZTF-16 transcription factor binding site within the lin-42BC promoter abolishes tissue-specific expression patterns. Together, these data indicate that ZTF-16 is required to regulate the expression of lin-42A/B during C. elegans development, and may do this by direct binding to the lin-42BC promoter. Our  findings pave the way for testing the possible regulation of period expression by HIL-family transcription factors in mammalian tissues. / Master of Science
293

Úloha fosfatidylinositol-4-fosfát 5-kinázy PPK-1 v regulaci signální dráhy proteinu Wnt u Caenorhabditis elegans / The role of phosphatidylinositol-4-phosphate 5-kinase PPK-1 in Wnt signalling regulation in Caenorhabditis elegans

Zavadilová, Kristýna January 2021 (has links)
The Wnt signalling pathway is highly conserved signalling among Eukaryotes that regulates many cellular processes. In particular, it plays a role during invidual's development, but it is also important at later stage of life, when it is involved in maintaining homeostasis in the body. Recent studies have shown that phosphatidylinositol-4-phospahte 5-kinase (PIP5K), which is key to the production of phosphatidylinositol (4,5)-bisphosphate in the cell, is also involved in regulation of the canonical Wnt signalling cascade. In mammalian cells, a model has been described in which PIP5K is involved in signal transduction in a Wnt receiving cell. We decided to verify the involvement of PIP5K in the regulation of Wnt signalling also in Caenorhabditis elegans, an excellent model organism for study of signalling pathways, and thus contribute to a better understanding of this evolutionarily conserved pathway. In this work, we found that decreased expression of PPK-1/PIP5K in wild type animals does not result in Wnt signalling disruption. Nevertheless, in conditions, where the activity of Wnt signalling is already reduced, decrease in PPK-1 levels leads to defective migration of the QL neuroblast daughter cell. By analyzing the migration of QL progeny, which is controlled by EGL-20/Wnt dependent Wnt...
294

Improved inapproximability of Max-Cut through Min-Cut / Förbättrad ickeapproximerbarhet för Max-Cut genom Min-Cut

Wiman, Mårten January 2018 (has links)
A cut is a partition of a graph's nodes into two sets, and we say that an edge crosses the cut if it connects two nodes belonging to different sets. A maximum cut is a cut that maximises the number of crossing edges. We show that for any sufficiently small ε > 0 it is NP-hard to distinguish between graphs for which at least a fraction 1 - ε of all edges crosses the maximum cut and graphs for which at most a fraction 1 - 1.4568 ε of all edges crosses the maximum cut. The previous state of the art had a constant smaller than 1.375 in place of 1.4568. / Ett snitt är en partition av en grafs noder i två mängder, och vi säger att en kant korsar snittet om dess ändpunkter tillhör olika mängder. Ett maximalt snitt är ett snitt som maximerar antalet kanter som korsar snittet. Vi bevisar att det för alla tillräckligt små konstanter ε > 0 är NP-svårt att skilja mellan grafer för vilka minst en andel 1 - ε av alla kanter korsar det maximala snittet och grafer för vilka högst en andel 1 - 1.4568 ε av alla kanter korsar det maximala snittet. Detta är en förbättring jämfört med ett tidigare resultat som hade en konstant mindre än 1.375 istället för 1.4568.
295

The Life and Teaching of Lin-Chi I-Shuan

Kato, Kazumitsu W 01 January 1957 (has links) (PDF)
In the tradition of the Zen school, all of the monks are required to study what are called the "seven books of Zen. These books are chosen from the old Zen masters' collections, but the "seven books" are different according to each of the schools of Zen. Therefore, it is not possible to say which are "the seven books," but Lin-chi Lu is always listed as the first one of them in every school of Zen.
296

Intermedialität zwischen Wort, Bild und Musik im Werk Kurt Tucholskys

Pistocchi, Francesca 13 July 2023 (has links)
Il progetto verte principalmente sullo studio dell’intermedialità nell’opera di Kurt Tucholsky, mettendo in comunicazione i testi dell’autore con la produzione saggistica che, fra la fine degli anni ’90 e l’inizio del nuovo millennio, descrive il rapporto fra scrittura, visione e suono. Scopo dell’indagine è tracciare un ritratto inedito di Tucholsky sostituendo, alla tradizionale prospettiva storico-biografica, un approccio di tipo formale e giungendo ad osservare la sua figura sotto una nuova luce.
297

CALaMo: a Construsctionist perspective on the Analysis of linguistic behaviour of Language Models

Pannitto, Ludovica 17 May 2023 (has links)
In recent years, Neural Language Models (NLMs) have consistently demonstrated increasing linguistic abilities. However, the extent to which such networks can actually learn grammar remains an object of investigation, and experimental results are often inconclusive. Notably, the mainstream evaluation framework in which NLMs are tested seems largely based on Generative Grammar and nativist principles, and a shared constructionist approach on the matter has not yet emerged: this is at odds with the fact that usage-based theories are actually better suited to inspect the behaviour of such models. The main contribution of this thesis is the introduction of CALaMo, a novel framework for evaluating Neural Language Models’ linguistic abilities, using a constructionist approach. We especially aim at formalizing the relationship between the computational modelling phase and the underlying linguistic theory, thus allowing a more refined and informed discussion of settings and results. We focus on two specific areas that, we believe, are currently not easily tractable within the mainstream evaluation framework. The first scenario deals with language acquisition from child-directed data. Our main experimental result shows how it is possible to follow schematization paths during the acquisition process of the model, and how this relates to core hypotheses in constructionist theories. The second scenario deconstructs the mainstream view of the Neural Model as an average idealized speaker by proposing a way to simulate and analyze a population of artificial individuals. We show how the amount of “shared linguistic knowledge” across speakers is highly dependent on the specific linguistic background of each individual. Overall, we believe our framework opens the path for future discussion on the role of computational modelling in usage-based linguistic theory and vice versa, and provides a new formal methodology to both fields of study.
298

Patterns in clitic pronouns: assessment of clitics in Italian in typical and non-typical populations

Smith, Giuditta 18 February 2021 (has links)
Clitic pronouns are linguistic elements which stand at the crossroads between different areas of the language faculty. They have specific morphology, syntax, and discourse functions. Use of this element requires the management of several aspects that draw from these areas of language. Clitics have been shown to appear early in typical acquisition, but to require longer for all aspects to be correctly managed, and they proved effortful in other modes of acquisition and atypical language, where they are clinical markers of impairment. In this work, we implement a comprehensive assessment of clitics aiming to investigate in what way different occurrences of this structure highlight different patterns of linguistic performance. To do so, we focus both on accuracy across conditions and on answer strategies, with an experimental protocol testing the following: comprehension of reference in binding constructions, production of clitics in two argument positions (direct object and indirect object), production of clitics in two sentence positions (preverbal and postverbal), production of clitics with different person features (1st/2nd and 3rd), and pragmatic abilities in the alternation with the lexical noun phrase and in perspective shift contexts. The assessment was tested on the following groups of native speakers of Italian: a group of pre-school and primary school typically developing children (Study 1), a group of adult heritage speakers of Italian living in the UK (Study 2), and four (pre)adolescents with a diagnosis of ASD (Study 3). Results found in this work showed that a comprehensive assessment of clitics can highlight similarities as well as differences in linguistic profiles according to different groups. Specifically, comprehension was not a discriminating factor in the populations: all populations tested showed to have access to abstract representations of clitics in binding constructions, as comprehension of simple clitics was generally unproblematic. An exception was found in the pre-schoolers, but this may have been due to task-related factors. In line with previous results on typical, atypical, and bilingual populations, production of Italian 3rd person direct object clitics with finite verbs showed different patterns across populations: in our data, typical children of all ages and ASD pre-adolescents showed to correctly produce this instance of the clitic the majority of the time, while heritage speakers of Italian showed poor production rates on this instance of the clitic. Importantly, our data shows similar results for indirect objects, showing that if the cliticization process is accessible, it is accessible regardless of the argument position occupied by the cliticised object. Another crucial result is that our studies find different patterns to be highlighted by the production of clitics on non-finite verbs as opposed to those on finite verbs: accuracy is similarly high in one high-performing ASD pre-adolescent and in the group results of 8-year-old children, but 4-year-old and 6-year-old children, as well as some ASD participants show chance or below chance performance in enclisis. The same was true for production of clitic combinations, although it was the least accurate structure across all groups, particularly in non-finite constructions. Here, heritage speakers and a few ASD speakers produce little to no instances of this construction, while those who produce it the most are the highest performing ASD participant and the oldest group of children. It is plausible to assume that the derivation of both enclitics and clitic combinations may require harder computation. These results allow us to conclude that if an individual or a population has issues on single DO and IO clitics with finite verbs, they will have issues with all other instances in the assessment. If an individual or a population shows no issues on single DO and IO clitics with finite verbs, they show typical language. In this, single clitics are coherent to their role of clinical markers. However, this study highlights the power of other instances of clitics, namely enclitics and clitic combinations, to unearth vulnerabilities to complex language. Types of non-target response also showed to be in part characterizing of different populations. The most striking result in this sense is the production of a lexical NP in place of the clitic. In typical development, this answer type only becomes the most used alternative answer in the hardest constructions, namely in enclisis; on the other hand, heritage speakers systematically use this construction as the alternative to clitics and use it more than they use clitics across all conditions. In our results, errors that are usually associated with impairment, particularly in younger participants, were marginally present in all groups. These are errors on the φ-features of the clitics, omissions, and misplacements (of which we found no instances), and they were limited to the youngest TD group, the heritage speakers, and the lowest-performing ASD participant. A recurrent alternative structure employed in conditions eliciting enclitics was the production of a simplified, finite verb structure.
299

Au-delà du formalisme. La critique des écrivains en France et en Italie pendant la seconde moitié du XXe siècle

Lorandini, Francesca January 2014 (has links)
My dissertation covers the field of what Albert Thibaudet called “the critique of artists†in order to show that, throughout the second half of the twentieth century, this form of criticism has given readers a different perspective on literature in comparison to that of the formalists and the neo-avant-garde. In the first part of my study, I examine the evolution of formalist criticism in the twentieth century, considering the linguistic turn of the 1960s as the natural outcome of a cultural revolution which took place at the end of the nineteenth century. By conducting a comparative study between France and Italy, I attempt to outline a transnational model which shows that the two formalist critiques share the same understanding of the literature postulated by the neo-avant-garde. The second part of my thesis is devoted to the study of one of the main tendencies in the critique of the writers since the Second World War, a tendency that called into question a purely intrinsic study of the work of art. Here, I propose a comparative study of the literary critique of Georges Perec, Michel Tournier, Philippe Muray, Tommaso Landolfi, Pier Paolo Pasolini and Pier Vittorio Tondelli, in order to underline that their critical practice has not limited itself to a personal declaration of their poetic views, but it has truly opened up an alternative approach to formalist theoretical positions. They refused to speak of literature as a secluded world, and by doing so they anticipated one of the most important features of the literature of the end of the twentieth century, both in France and in Italy.
300

The syntactic side of Time: processing Adverb-Verb Temporal Agreement

Biondo, Nicoletta January 2017 (has links)
The aim of this thesis deals with the investigation of the cognitive mechanisms underlying the online processing of adverb-verb temporal agreement, namely the coherence in temporal features between the verb and a deictic temporal adverb (e.g. YesterdayPAST I wentPAST/*will goFUT to the jazz concert), during sentence comprehension. There are at least two reasons that make the investigation of this phenomenon interesting and challenging at the same time. The first reason is more theoretical. Differently from well-studied phenomena such as subject-verb agreement or anaphora, the nature of the adverb-verb relation is still debated in theoretical linguistics. The debated nature of the adverb-verb temporal agreement probably relies on the peculiar properties of the constituents involved in the relation. The relation between temporal adverbs and verbs has been traditionally defined anaphoric in nature, since verbs can be bound to temporal antecedents (e.g. adverb) which allow to set a reference time that the event expressed by the verb must refer to. However, other accounts have hypothesized a structural parallelism between the adverb-verb and the subject-verb relation. One question is thus whether this similarities or dissimilarities between subject-verb agreement and temporal agreement at the theoretical level can mirror a similarity/dissimilarity at the cognitive level. The second reason is more empirical and comes from past experimental literature investigating the processing of temporal agreement. Basically, experimental evidence mainly comes from ERPs studies and results are rather sparse and heterogeneous. These ERP studies report an early detection of the temporal violation (around 200 milliseconds after the stimulus onset) but qualitatively different ERP waveforms were elicited by the target word (i.e. the verb) in the different experiments (e.g. LAN, N400, right lateralized negativities). One licit question is thus where the source of heterogeneity resides and how this phenomenon can be better investigated. Given the debated theoretical and experimental past evidence on the processing of this relation, the current work was conducted (i) investigating the pattern elicited by adverb-verb temporal violations compared to other better-studied agreement phenomena, as the one between the subject and the verb, during sentence comprehension (ii) adopting only behavioral techniques since a detailed investigation of the behavioral costs elicited by a temporal violation needs to be established prior to facing the detailed neurophysiological correlates of these processes, which are known to be subject to a larger interpretive freedom with respect to reading time differences. The core of the thesis, namely six empirical studies investigating the processing of temporal violations through different designs and techniques, is preceded by a theoretical chapter which deals with the description of Tense and deictic temporal adverbs from a semantic and syntactic point of view. The main aim of the theoretical chapter is to give a brief overview of the main linguistic theories which have investigated the nature of Tense and temporal adverbs, but also a motivation for considering the syntactic interaction between Tense and temporal adverbs, which is fundamental to preserve the grammaticality of the sentence.The first set of self-paced reading studies, in Italian, addressed two main questions: how different is the processing of adverb-verb temporal agreement with respect to other better-studied phenomena such as subject-verb number agreement? Is the different configuration between the verb and the temporal adverb that has led to heterogeneous results in past experimental literature? In the second (eye-tracking) study, in Spanish, three other questions were addressed: how differently the parser deals with the processing of number, tense and (crucially) person features when encountering a violation on the inflected verb? Does the distance between the two constituents of the dependency play any role in the detection of the violation? Finally, in the third set of eye-tracking studies in English, the processing of the adverb-verb temporal relation was tested in a more complex sentential environment, namely in sentence where the temporal adverb and the verb are separated by an embedded relative clause containing a distracting temporal element. In this set of studies, several questions were addressed: how different can be the processing of adverb-verb temporal agreement at a conspicuous distance? Is the temporal adverb-verb relation sensitive to interference effects from an illicit intervener? How differently this relation behaves with respect to subject-verb agreement and anaphora during memory retrieval? All findings collected in this work provide further evidence for a differentiation in the processing of agreement mechanisms entailing a covariance of features between two constituents within a sentence. This evidence is in line with previous accounts showing a differentiation in the processing of different features (i.e. number, person) within the same relation such as subject-verb agreement (Mancini et al. 2013), and in the processing of the same feature (e.g. number) across different relations such as subject-verb agreement and anaphora (Dillon et al. 2013). This evidence can be particularly relevant for the development of a new model of sentence parsing. In fact, among mainstream models of parsing, only Construal (Frazier & Clifton, 1996) model assumes a relation-sensitive language system. However, a differentiation in the processing of agreement phenomena is not explicitly addressed in terms of feature-related properties. On the other hand, some recent accounts have proposed different processing mechanisms depending on the feature under computation (e.g. Mancini et al., 2013; Carminati, 2005) but a specific formalization of the role of different features properties within a model of parsing has not been provided yet. The second challenge that this current work tried to face was to add more complexity into the agreement configuration testing the adverb-verb agreement relation at different linear distance. The findings here collected seems to give positive evidence on the role played by word order in the processing of the adverb-verb relation, but further investigation needs to address whether other factors may play a role and whether adverb-verb agreement is the only agreement relation which is sensitive to word order. This puzzle thus opens new questions about whether the agreement relation may change even being both the relation and the feature under computation equal. The role played by linear distance in the detection of adverb-verb temporal anomalies also suggests that parsing routines are not “stagnant†, and the language system can deal with redundant information in a very dynamic fashion.

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