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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.
341

Entwicklung eines dreidimensional wirkenden Vibrationstisches für eine Lost-Foam-Gießanlage

Ruffert, Manfred 23 July 2009 (has links) (PDF)
Die wichtigste Baugruppe im Verfahrensablauf einer Lost-Foam-Gießanlage ist neben der Gießstation die Vibrationseinrichtung. Diese Einrichtung dient dem Befüllen eines Gießbehälters mit Gießmodell bei gleichzeitigem Verdichten des Formsandes. Es wurden vier Varianten einer dreidimensionalen Vibrationseinrichtung entworfen, teilweise konstruiert und in ihrer Machbarkeit verglichen. Modelliert und simuliert wurde das dynamische Bewegungsverhalten des servohydraulisch angetriebenen dreidimensionalen Vibrationstisches. Es zeigte sich die Eignung der konstruierten Vibrationseinrichtung, ebenfalls wiesen Spannungs- und Verformungsanalysen zur Optimierung eines neuen Gießbehälters seine geforderten Einsatzmöglichkeiten nach. Die Vorzugsvariante, ein dreidimensional servohydraulisch angetriebener Vibrationstisch ohne Klemmrahmen, konnte in eine neue Lost-Foam-Gießanlage projektiert werden.
342

Caractérisation des traits biologiques et des processus évolutifs d'une espèce envahissante en France : Ambrosia artemisiifolia L.

Fumanal, Boris 24 April 2007 (has links) (PDF)
Ambrosia artemisiifolia L. (Asteraceae) est une plante annuelle originaire d'Amérique du Nord, introduite accidentellement à la fin du 19ème siècle en Europe. En France, cette espèce envahissante est à l'origine d'importants problèmes de santé publique causés par son pollen allergisant. C'est également une adventice problématique dans certaines cultures de printemps. Plus généralement, l'espèce colonise tous types d'habitats perturbés par l'homme. Son développement dans les milieux naturels semble cependant limité aux habitats régulièrement perturbés (grèves des rivières).<br />L'objectif de ce travail de thèse a été d'étudier à travers une approche multidisciplinaire, les différentes caractéristiques de l'espèce, tant biologiques, génétiques, qu'écologiques, ainsi que les caractéristiques des communautés envahies, pouvant permettre d'expliquer le succès de son envahissement en France.<br />Une synthèse bibliographique a été réalisée sur les différents paramètres impliqués dans les phénomènes d'invasions biologiques et sur les connaissances actuelles du modèle étudié, A. artemisiifolia.<br />Les différents traits d'histoire de vie de l'espèce ont révélé une variabilité considérable, en particulier au niveau des semences, ce qui suggère l'existence d'une stratégie adaptée à la colonisation d'environnements variables. L'importante plasticité phénotypique d'A. artemisiifolia mise en évidence, explique en partie le succès de cet envahisseur. La dynamique générale des populations (taux d'accroissement) est également différente entre habitats. Le facteur limitant la colonisation ou le maintien des populations est sans conteste la fermeture du milieu. De plus, la présence de mycorhizes à arbuscules dans les communautés envahies serait également un des facteurs susceptibles de faciliter le processus d'envahissement de l'espèce.<br />D'autre part, le potentiel d'envahissement de cette espèce peut s'expliquer par les niveaux de diversité génétique très élevés des populations natives et introduites, observés à l'aide de différents marqueurs moléculaires (ADNcp, AFLP). Ces résultats suggèrent également que l'espèce a été introduite à de multiples reprises, à partir de différentes sources et avec un nombre important de fondateurs. <br />Enfin, nos résultats montrent qu'A. artemisiifolia possède une amplitude écologique très large et qu'elle n'est pas spécifiquement inféodée à un groupement végétal particulier. L'espèce est donc capable de coloniser des environnements écologiquement différents et peut potentiellement accroître son aire de distribution de manière considérable.<br />Les connaissances acquises au cours de cette thèse montrent que l'invasion d'A. artemisiifolia est un phénomène multifactoriel. L'envahissement de cette espèce dépend avant tout des conditions rencontrées lors de son processus d'introduction et de colonisation (habitats perturbés, dispersion anthropique). Son caractère généraliste lui permet ensuite de pouvoir répondre de manière optimale aux conditions environnementales rencontrées. Nos résultats suggèrent que dans le contexte actuel, A. artemisiifolia présente un potentiel d'envahissement considérable en France comme dans le reste de l'Europe.
343

Čen stiliaus Taidzičiuan treniruočių programos įtaka esant nuolatiniam apatinės nugaros dalies skausmui / Impact of Chen style Taijiquan training program on chronic low back pain

Rožėnas, Egidijus 10 October 2012 (has links)
Darbo objektas: nuolatinio (> 3 mėn.) apatinės nugaros dalies skausmo, negalios dėl jo, judamojo atraminio aparato funkcinių ir pusiausvyros rodiklių pokytis po 8 savaičių Čen stiliaus Taidzičiuan treniruočių įtakos. Tyrimo problema: ar Čen stiliaus Taidzičiuan treniruočių programa gali įtakoti rodiklius susijusius su nuolatiniu apatinės nugaros dalies skausmu? Hipotezė: Čen stiliaus 8 savaičių trukmės Taidzičiuan treniruočių programa turi teigiamą įtaką, skausmo bei su juo susijusios negalios, judamojo atraminio aparato funkciniams bei pusiausvyros rodikliams esant apatinės nugaros dalies skausmui. Tikslas: nustatyti, kokią įtaką turi 8 savaičių trukmės Čen stiliaus Taidzičiuan treniruočių programa esant nuolatiniam apatinės nugaros dalies skausmui. Uždaviniai: 1. nustatyti skausmo ir negalios dėl jo rodiklius bei įvertinti jų kaitą; 2. nustatyti judamojo atraminio aparato funkcinius rodiklius bei įvertinti jų kaitą; 3. nustatyti pusiausvyros rodiklius ir įvertinti jų kaitą. Tiriamieji: 10 tiriamųjų (8 moterys ir 2 vyrai, 42,8 ± 11,6 metų amžiaus, 168,1 ± 4,6 cm ūgio, 66,3 ± 13,0 kg svorio, nuolatinio apatinės nugaros dalies skausmo trukmė – 8,6 ± 7,7 metai). Išvados: 8 savaičių trukmės Čen stiliaus Taidzičiuan treniruočių programa, esant nuolatiniam apatinės nugaros dalies skausmui yra efektyvi mažinant skausmą bei negalią dėl jo, tačiau neturi reikšmingos įtakos judamojo atraminio aparato funkciniams rodikliams (išskyrus padidėjusį lankstumą į šonus, bei kairės kojos... [toliau žr. visą tekstą] / Subject of study: impact of 8 weeks duration Chen style Taijiquan training program on chronic (> 3 month) low back pain, disability, functional musculoskeletal system and balance indicators. Problem of study: can Chen style Taijiquan training program influence indicators, which are related with chronic low back pain? Hypothesis: 8 weeks duration Chen style Taijiquan training program has positive influence on pain, disability, functional and balance indicators for people, who have chronic low back pain. The aim: to assess, what impact has 8 weeks duration Chen style Taijiquan training program on chronic low back pain, disability, functional and balance indicators. Objectives: 1. to assess indicators of pain and disability and evaluate alternation; 2. to assess functional indicators of body and evaluate alternation; 3. to assess indicators of balance and evaluate alternation. Participants: 10 participants (8 woman and 2 man, 42,8 ± 11,6 year old, height - 168,1 ± 4,6 cm, weight - 66,3 ± 13,0 kg, duration of chronic low back pain - 8,6 ± 7,7 years). Conclusions: 8 weeks duration Chen style Taijiquan training program has positive influence on reducing pain and disability, but does not have influence on functional indicators of body (except increase range of side flexibility and length of left leg posterior muscles). Balance indicators (length of swinging trajectory and average swinging speed) also were not influenced.
344

Aspects of Fourier imaging

Hsiao, Wen-Hsin January 2008 (has links)
A number of topics related to Fourier imaging are investigated. Relationships between the magnitude of errors in the amplitude and phase of the Fourier transform of images and the mean square error in reconstructed images are derived. The differing effects of amplitude and phase errors are evaluated, and "equivalent" amplitude and phase errors are derived. A model of the probability density function of the Fourier amplitudes of images is derived. The fundamental basis of phase dominance is studied and quantitated. Inconsistencies in published counter-examples of phase dominance are highlighted. The key characteristics of natural images that lead to their observed power spectral behaviour with spatial frequency are determined.
345

Why so different? - Aspects of voice characteristics in operatic and musical theatre singing : Aspects of voice characteristics in operatic and musical theatre singing

Björkner, Eva January 2006 (has links)
This thesis addresses aspects of voice characteristics in operatic and musical theatre singing. The common aim of the studies was to identify respiratory, phonatory and resonatory characteristics accounting for salient voice timbre differences between singing styles. The velopharyngeal opening (VPO) was analyzed in professional operatic singers, using nasofiberscopy. Differing shapes of VPOs suggested that singers may use a VPO to fine-tune the vocal tract resonance characteristics and hence voice timbre. A listening test revealed no correlation between rated nasal quality and the presence of a VPO. The voice quality referred to as “throaty”, a term sometimes used for characterizing speech and “non-classical” vocalists, was examined with respect to subglottal pressure (Psub) and formant frequencies. Vocal tract shapes were determined by magnetic resonance imaging. The throaty versions of four vowels showed a typical narrowing of the pharynx. Throatiness was characterized by increased first formant frequency and lowering of higher formants. Also, voice source parameter analyses suggested a hyper-functional voice production. Female musical theatre singers typically use two vocal registers (chest and head). Voice source parameters, including closed-quotient, peak-to-peak pulse amplitude, maximum flow declination rate, and normalized amplitude quotient (NAQ), were analyzed at ten equally spaced subglottal pressures representing a wide range of vocal loudness. Chest register showed higher values in all glottal parameters except for NAQ. Operatic baritone singer voices were analyzed in order to explore the informative power of the amplitude quotient (AQ), and its normalized version NAQ, suggested to reflect glottal adduction. Differences in NAQ were found between fundamental frequency values while AQ was basically unaffected. Voice timbre differs between musical theatre and operatic singers. Measurements of voice source parameters as functions of subglottal pressure, covering a wide range of vocal loudness, showed that both groups varied Psub systematically. The musical theatre singers used somewhat higher pressures, produced higher sound pressure levels, and did not show the opera singers’ characteristic clustering of higher formants. Musical theatre and operatic singers show highly controlled and consistent behaviors, characteristic for each style. A common feature is the precise control of subglottal pressure, while laryngeal and vocal tract conditions differ between singing styles. In addition, opera singers tend to sing with a stronger voice source fundamental than musical theatre singers. / <p>QC 20100812</p>
346

L'effet de la manipulation vertébrale sur la douleur provoquée expérimentalement

Millan, Mario 06 February 2014 (has links) (PDF)
La manipulation vertébrale (MV) est l'une des options dans le traitement des douleurs d'origine neuromusculosquelettique. Ses indications ont été identifiées à partir de l'expérience des professionnels qui l'utilisent, ainsi que des études épidémiologiques autour de ses résultats cliniques. Cependant, son mécanisme d'action précis demeure à ce jour inexpliqué.La littérature scientifique sur ce sujet est incomplète, éparse et confuse. Certains auteurs et professionnels proposent des hypothèses des mécanismes d'action neurobiologiques et d'autres biomécaniques. De plus, l'étude de la douleur rend la situation difficile en raison de la complexité des situations cliniques et des traitements associés dont les patients bénéficient. C'est la raison pour laquelle l'objectif de cette thèse est d'étudier si la MV a un effet sur la douleur provoquée de manière expérimentale. Si tel est le cas, il importe de savoir s'il est systémique ou locorégional et dans cette dernière hypothèse, si ce résultat est le produit d'une action directe de la MV sur la douleur ou secondaire à une amélioration du mouvement. N'ayant pas trouvé d'étude englobant la problématique mixte des effets de la MV sur la douleur et le mouvement, nous avons procédé à deux revues systématiques et critiques de la littérature scientifique ; l'une a porté sur son effet sur la douleur et l'autre sur l'amplitude du mouvement des segments vertébraux. Dans la première, nous avons rassemblé 22 articles décrivant 43 essais cliniques montrant un effet hypoalgésique de la MV au niveau locorégional, mais les résultats diffèrent selon la manière dont la douleur a été provoquée. Nous n'avons pas pu tirer de conclusion sur l'action systémique de la MV du fait de la qualité des articles sur ce sujet. Quant à la revue de la littérature réalisée sur l'effet de la MV sur l'amplitude du mouvement, l'étude de 15 articles ne nous a pas permis de prouver l'efficacité de cette technique pour augmenter l'amplitude des mouvements segmentaires, malgré des limitations à prendre en considération, notamment le fait que ces études ont été réalisées sur des volontaires sains et non sur des patients avec une mobilité réduite. A partir de là, nous concluons que l'effet de la MV sur la douleur est plutôt direct, et défendons la thèse que l'hypoalgésie induite par la MV permet l'amélioration et la récupération de la fonction de mouvement, et non l'inverse.Cependant, même si nous répondons à nos questions de recherche, ces réponses demeurent partielles et le sujet reste à approfondir. Nos deux revues indiquent qu'il reste à clarifier : les mécanismes exacts des effets de la MV sur la douleur, la durée des effets, les rapports "dose/effet", l'identification des techniques les plus efficaces, ou encore, sur le ciblage plus fin des patients à traiter. Il en est de même en ce qui concerne l'étude de l'effet de la MV sur l'amplitude du mouvement, où il manque notamment des études réalisées sur des patients et des personnes présentant des mouvements limités. Des améliorations sont également à prévoir dans la coordination des chercheurs les rassemblant autour d'une politique de recherche partagée sur le long/moyen terme, et à partir d'un consensus méthodologique, particulièrement en termes de suivi des essais, d'unités de mesures, de précision des critères de qualité des essais, de promotion de méta-analyses, etc. Au total, si la MV semble avoir un effet direct sur la douleur, il n'en demeure pas moins que la connaissance détaillée de ses mécanismes et des modalités d'application dans la pratique clinique reste à approfondir, ce qui pourrait devenir un véritable enjeu pour la communauté des chercheurs, des enseignants et des cliniciens.
347

Superfluid spherical Couette flow and rotational irregularities in pulsars /

Peralta, Carlos Andrés. January 2006 (has links)
Thesis (Ph.D.)--University of Melbourne, School of Physics, 2007. / Typescript. Includes bibliographical references (leaves 275-308).
348

The dynamics of the G protein-coupled neuropeptide Y2 receptor in monounsaturated membranes investigated by solid-state NMR spectroscopy

Thomas, Lars, Kahr, Julian, Schmidt, Peter, Krug, Ulrike, Scheidt, Holger A., Huster, Daniel 08 January 2016 (has links) (PDF)
In contrast to the static snapshots provided by protein crystallography, G protein-coupled receptors constitute a group of proteins with highly dynamic properties, which are required in the receptors’ function as signaling molecule. Here, the human neuropeptide Y2 receptor was reconstituted into a model membrane composed of monounsaturated phospholipids and solid-state NMR was used to characterize its dynamics. Qualitative static 15N NMR spectra and quantitative determination of 1H-13C order parameters through measurement of the 1H-13C dipolar couplings of the CH, CH2 and CH3 groups revealed axially symmetric motions of the whole molecule in the membrane and molecular fluctuations of varying amplitude from all molecular segments. The molecular order parameters (Sbackbone = 0.59-0.67, SCH2 = 0.41-0.51 and SCH3 = 0.22) obtained in directly polarized 13C NMR experiments demonstrate that the Y2 receptor is highly mobile in the native-like membrane. Interestingly, according to these results the receptor was found to be slightly more rigid in the membranes formed by the monounsaturated phospholipids than by saturated phospholipids as investigated previously. This could be caused by an increased chain length of the monounsaturated lipids, which may result in a higher helical content of the receptor. Furthermore, the incorporation of cholesterol, phosphatidylethanolamine, or negatively charged phosphatidylserine into the membrane did not have a significant influence on the molecular mobility of the Y2 receptor.
349

Rhythmic sensitivity and developmental language disorder in children

Richards, Susan Mary January 2017 (has links)
Children with Developmental Language Disorder (DLD) have difficulties in acquiring language in the absence of other neurodevelopmental issues (e.g. autism, hearing impairment) and despite growing up in an adequate language-learning environment. Previous characterisations of DLD have focused on grammatical processing, phonological memory or rapid auditory processing. This thesis approaches the language-learning difficulties of children with DLD from a novel perspective by considering the potential contribution made by differing levels of sensitivity to the rhythmic properties of language. Children with DLD have been shown to have reduced sensitivity to some of the acoustic cues present in speech which are thought to be important for rhythmic perception. Since rhythm forms the basis of language processing in early development, poorer sensitivity to language rhythm may result in later language problems. To investigate whether children with DLD demonstrate difficulties in processing language rhythm, this thesis explores five areas of language processing which could be affected by poor rhythmic sensitivity: locating word-boundaries, processing novel words, storing lexical stress patterns, representing sentence level structures and the integration of rhythm and syntax. As part of the investigation, measures were also taken of acoustic threshold sensitivity to see whether task performance related to acoustic sensitivity. A parallel strand of the study investigated whether provision of an entraining rhythm prior to task stimuli could support task performance. Three groups of children participated in the study: children with DLD, age-matched TD children (AMC) and younger, language-matched TD children (YLC). The results indicate that rhythmic manipulation of language stimuli affects task responses across the five language areas under investigation. The findings are then discussed in terms of the contribution made to our understanding of the role of rhythm in language and language disorder.
350

Reprodutibilidade da avaliação da força muscular, da amplitude de movimento e da funcionalidade do quadril em sujeitos saudáveis

Morales, Anete Beling January 2015 (has links)
INTRODUÇÃO: A avaliação da articulação do quadril continua sendo considerada complexa e desafiadora. Avanços recentes nas técnicas cirúrgicas e de imagem têm contribuído para a identificação das estruturas que contribuem para a dor no quadril. Medidas válidas, confiáveis, reprodutíveis e repetíveis são necessárias para que se possa identificar mudanças que ocorreram na articulação do quadril ao longo do tempo, e para avaliar os desfechos do tratamento realizado. Tanto no ambiente clínico como no de pesquisa, um processo sistemático de avaliação é fundamental para constituir uma prática baseada em evidência. Entretanto, são poucos os estudos encontrados na literatura que avaliaram a reprodutibilidade da avaliação da força muscular, da amplitude de movimento (ADM) e da funcionalidade do quadril em sujeitos saudáveis, medidas fundamentais para que se possa avaliar os efeitos de intervenções clínicas no tratamento de pacientes com problemas na articulação do quadril e comparar com dados normativos. OBJETIVO: Avaliar a reprodutibilidade de um protocolo de avaliação da força muscular, ADM e funcionalidade de quadril em sujeitos saudáveis. MATERIAIS E MÉTODOS: 15 voluntários saudáveis (30 quadris), de ambos os sexos, entre 22 e 37 anos, foram submetidos ao teste e reteste, com um único avaliador, da força muscular, da amplitude de movimento e da funcionalidade do quadril. Quatro sessões de avaliação foram realizadas no Setor de Plasticidade Neuromuscular do Laboratório de Pesquisa do Exercício da Universidade Federal do Rio Grande do Sul. As avaliações foram compostas por: (1) medidas antropométricas, (2) aplicação de questionários funcionais, (3) teste de agachamento unipodal, (4) avaliação fotogramétrica e goniométrica da ADM do quadril, (5) teste de força máxima com dinamômetro manual e dinamômetro isocinético, (6) avaliação da dor. RESULTADOS: a dinamometria manual apresentou excelente reprodutibilidade, com coeficiente de correlação intraclasse (CCI) > 0,9 (com intervalos de confiança (ICs) entre 0,85 e 0,99) e valores de erro padrão de medida relativo (EPM%) inferiores a 10%. Os testes dos rotadores externos em 0°, 10° e 20° de rotação interna; dos rotadores internos em 15° de rotação externa e dos abdutores do quadril da dinamometria isocinética e os da rotação externa ativa e passiva e da rotação interna bilateral passiva da fotogrametria da ADM do quadril também apresentaram reprodutibilidade considerada excelente, com CCIs > 0,75, e valores aceitáveis do EPM e EPM%. Porém, tanto na dinamometria isocinética quanto na avaliação da ADM, em muitas das situações testadas, os testes permaneceram com a reprodutibilidade entre razoável e boa (CCIs entre 0,48 a 0,75, no geral), com ICs muito amplos, principalmente para a avaliação da ADM. No dinamômetro isocinético, os testes dos rotadores externos foram mais reprodutíveis que o dos rotadores internos; e os testes em extremos articulares de ambos rotadores foram menos reprodutíveis. A classificação do Kappa do teste de agachamento unipodal foi satisfatória (k=0,59). Os testes menos reprodutíveis foram: a fotogrametria da abdução ativa do quadril (CCI=0,39), da abdução passiva do quadril (CCI=0,48) e a ADM ativa de flexores do quadril realizada com um goniômetro (CCI=0,51). CONCLUSÃO: Uma boa parte dos testes apresentou reprodutibilidade excelente e justifica a aplicação no ambiente clínico, quando realizados por um único avaliador. Entretanto, aprimoramentos nas técnicas utilizadas são necessários a fim de melhorar a reprodutibilidade e reduzir os erros de medida na avaliação do quadril. / INTRODUCTION: The assessment of the hip is still considered complex and challenging. Recent advances in surgical and imaging techniques have contributed to the identification of structures that contribute to hip pain. Measures that are valid, reliable, reproducible and repeatable are necessary to identify changes that have occurred at the hip joint over time, and to evaluate the treatment outcomes. Both at the clinical and research settings, a systematic evaluation process is crucial to provide an evidence-based practice. However, there are few studies in the literature that evaluated the reliability of muscle strength, range of motion (ROM) and hip function measurements in healthy subjects, fundamental steps to assess the effects of clinical interventions in the treatment of patients with problems in the hip joint and compare with normative values. PURPOSE: To evaluate the reliability of an assessment protocol of muscle strength, ROM and hip functionality in healthy subjects. MATERIALS AND METHODS: 15 healthy volunteers (30 hips), of both sexes, between 22 and 37 years of age, were submitted to the test and retest, with a single investigator, of muscle strength, ROM and hip functionality. Four test sessions were held at the Neuromuscular Plasticity Department of the Exercise Research Laboratory at the Federal University of Rio Grande do Sul. The hip assessment included: (1) anthropometric measurements, (2) patient-reported outcome measures, (3) single leg squat test, (4) photogrammetric and goniometric hip ROM examination, (5) maximum strength test with handheld and isokinetic dynamometers, (6) pain evaluation by intensity rating scale. RESULTS: the handheld dynamometer showed excellent reliability with intraclass correlation coefficient (ICC) > 0.9 (with confidence intervals (CIs) between 0.85 and 0.99) and relative standard error values (% SEM) of less than 10%. The external rotators tests at 0°, 10° and 20° of internal rotation; internal rotators at 15° of external rotation, and hip abductors on an isokinetic dynamometer, and active and passive external rotation and bilateral passive internal rotation taken by photogrammetric analysis of the hip also showed excellent reliability, with ICCs> 0.75, and acceptable SEM and SEM% values. However, in many tests performed on the isokinetic dynamometer and in ROM assessment, the reliability remained between fair and good (ICCs between 0.48 to 0.75 overall), with very large CIs, especially for the assessment of ROM. At the isokinetic dynamometer, testing of the external rotators was more reliable than the internal rotators; and the strength rotators tests at the extremes ROMs the reliability was lower. The kappa interpretation for the single leg squat test was satisfactory (k = 0.59). The worst reliability tests were photogrammetry of active hip abduction (ICC = 0.39), passive hip abduction (ICC = 0.48) and active ROM of the hip flexors performed with a goniometer (ICC = 0.51). CONCLUSION: A good part of the tests showed excellent reliability and justifies the application at the clinical setting, when performed by a single investigator. However, improvements are needed in some of the used techniques to improve the reliability and reduce measurement errors in the assessment of the hip.

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