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Milanos, Lampros [Verfasser], Timothy [Gutachter] Clark et Markus [Gutachter] Heinrich. « Synthesis of the first allosteric biased agonists and computational investigations for the human chemokine receptor CXCR3 / Lampros Milanos ; Gutachter : Timothy Clark, Markus Heinrich ». Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2016. http://d-nb.info/1121913253/34.
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Anderson, Gretchen J. « Improving larval sea lamprey assessment in the Great Lakes using adaptive management and historical records ». Diss., Connect to online resource - MSU authorized users, 2006.
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Green, Ellen Marie. « Mechanisms of elasticity in elastic proteins ». Thesis, University of Exeter, 2012. http://hdl.handle.net/10036/4058.
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This thesis investigates the mechanical properties of the elastic proteins isolated by cyanogen bromide digestion from lamprey cartilages and compares them with the mammalian protein, elastin. Thermomechanical testing and measurements of the effects of hydrophobic solvents on mechanics are used to determine the energetic and entropic contributions to the mechanical properties and the role of solvent interactions. Raman microspectrometry is shown to be a valuable tool in determining the secondary structure of the proteins, their interactions with water and molecular-level effects of mechanical strain. The supramolecular structure of the proteins matrices are investigated using nonlinear microscopy and X-ray diffraction. The mechanical properties of fibrous elastin agreed with those previously reported with elastic moduli in the region of 0.2-0.4 MPa. Elastic moduli decrease by approximately 25% with increased temperature, which was accompanied by a small decrease in hysteresis loss. In agreement with earlier findings, an entropic mechanism of elasticity became dominant only at high temperatures with a major contribution from interactions with solvent water. The lamprey proteins can be divided into two broad groups, the 'soft' branchial and pericardial cartilages resembling elastin, with linear stress-strain behaviour over a range of strains, elastic moduli in the range 0.13 MPa to 0.35 MPa, breaking strains of up to 50% and low hysteresis. Annular and piston proteins showed a very different response having much higher elastic moduli (0.27 MPa to 0.75 MPa), higher breaking strains and large hysteresis. Similarities between elastin and the lamprey matrix proteins extended to their thermomechanical behaviour with a decrease in elastic moduli and a drive towards entropic elasticity at high temperatures, although the annulus and piston were less thermally stable. Raman spectroscopy was able to detect differences between the various proteins and between elastin fibres and fragmentation products. Although no vibrational modes associated with cross-linking of the fibres could be identified, the secondary structure of dehydrated fibrous elastin was significantly different from \alpha -elastin. The former differed from previous experimental measurements, but was close to the theoretical predictions with 36% \beta -structures, 46% unordered and 18% \alpha -helix. \alpha -Elastin contained 29% \beta -structures, 53% unordered and 18% \alpha -helix. Strains of up to 60% in ligament fibre bundles resulted in no significant shifts in peak positions or in secondary structure. Polarization measurements revealed that the peptide bonds and several of the bulky side-chains re-orientated closer to the fibre axis with strain. Heating nuchal elastin fibres to 60^{\circ} C to increase the energetic component of the elasticity was associated with a 30% increase in the proportion of \beta -structures in the amide I band, a 50% increase in the amide III band, and a 50% reduction in the signal from bound water. The Raman spectra of the lamprey matrix proteins are similar both to each other and when compared to fibrous elastin. Only small differences could be detected in side-chain modes consistent with reported biochemical differences. Decomposition of the amide I band indicated that the secondary structures were also very similar to that of elastin, with a preponderance of unordered structures which probably confer the high degree of conformational flexibility necessary for entropy elasticity. Piston and annular proteins, like elastin, showed a strong interaction with water, suggesting a greater role of hydrophobic interactions in their mechanics compared to the branchial and pericardial proteins. Elastin is well known to exhibit autofluorescence. However, only the branchial protein has been reported to autofluoresce. This study shows that all four lamprey matrix proteins investigated exhibit strong autofluorescence which was subsequently exploited to image these tissues using multiphoton microscopy. Microscopic investigations revealed that the architecture of lamprey proteins differ from that of elastin. Nuchal elastin forms bundles of fibres running predominantly parallel to the direction of applied force. The arrangement in lamprey cartilage is very different forming honeycomb structures, which in the case of annular and piston cartilages, is surrounded by a dense sheath of matrix material. Dye injections revealed that the branchial and pericardial form open systems whereas in piston and annular cartilages a closed system exists. These variations in architecture are reflected in their different mechanical properties and in vivo functions.
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Berg, Ingrid. « 3Cu ». Thesis, Högskolan i Borås, Institutionen Textilhögskolan, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-17095.
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Lagadec, Ronan. « Mécanismes de latéralisation de l'épithalamus chez la lamproie et la roussette ». Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066423/document.
Texte intégralRésumé :
Les vertébrés font partie des animaux à symétrie bilatérale mais celle-ci n'est pas parfaite et de nombreuses asymétries sont visibles entre les côtés gauche et droit, notamment au niveau du système nerveux. L'épithalamus s'est imposé comme le modèle de référence pour l'étude des mécanismes de latéralisation du cerveau. Cette structure dérivée du diencéphale dorsal se compose de deux noyaux bilatéraux, les habénulæ et du complexe pinéal, qui regroupe les glandes pinéale et parapinéale. Les habénulæ présentent des asymétries plus ou moins marquées chez tous les grands groupes de vertébrés. La parapinéale est également asymétrique mais elle est absente dans de nombreux taxa. Chez le poisson zèbre, espèce modèle de référence pour l'étude des mécanismes de formation des asymétries épithalamiques, une migration latéralisée de la parapinéale est nécessaire à l'élaboration des asymétries habénulaires. Les mécanismes génétiques sous-jacents ont également été en partie décryptés. La première asymétrie visible dans le diencéphale dorsal correspond à une activité de la voie de signalisation Nodal à gauche. Si cette voie Nodal est essentielle pour induire une asymétrie neurogénétique précoce, elle ne l'est pas pour la formation des asymétries épithalamiques définitives. Son rôle se restreint à biaiser la directionnalité des asymétries en influençant la migration de la parapinéale. Les asymétries habénulaires sont induites par la position finale de la parapinéale. La conservation à l'échelle des vertébrés des mécanismes décrits chez le poisson-zèbre reste une question ouverte. Au cours de ce travail de thèse, j’ai cherché à comprendre l’évolution de ces mécanismes en étudiant un chondrichtyen, la roussette Scyliorhinus canicula et des cyclostomes, les lamproies Petromyzon marinus et Lampetra planeri. Leur position phylogénétique ainsi que les asymétries majeures en taille observées entre les habénulæ gauche et droite font de ces espèces de bons modèles pour comprendre leur origine chez les vertébrés. Mes travaux conduisent à trois conclusions principales :(1) on retrouve, comme chez le poisson zèbre, une expression asymétrique de la voie Nodal dans le diencéphale dorsal gauche de la lamproie et de la roussette; la directionnalité de cette asymétrie est conservée entre les trois espèces, ce qui permet d’exclure une inversion de latéralité précédemment proposée chez la lamproie sur la base d’arguments de taille relative des habénulæ(2) La voie Nodal est essentielle à la formation des asymétries habénulaires chez la roussette et la lamproie, ce qui suggère un rôle ancestral dans l’élaboration des asymétries épithalamiques.(3) une analyse détaillée des patrons de prolifération-différenciation des habénulæ au cours du développement de la roussette met en évidence des asymétries moléculaires et cellulaires multiples ; elle démontre en particulier l’existence d’une neurogenèse asymétrique qui débute plus précocement à gauche. Ces travaux donnent un éclairage nouveau sur l’origine et la diversification des mécanismes contrôlant la formation des asymétries cérébrales chez les vertébrés. L’étude de la roussette et la lamproie, deux organismes modèles non conventionnels, ouvrent de nouvelles perspectives pour leur compréhensionVertebrates are part of the bilaterally symmetric animals but this one is not perfect and numerous asymmetries can be seen between the left and right sides, especially in the nervous system. The epithalamus has proven itself to be the model system for brain lateralization mechanisms’ studies. This structure derived from the dorsal diencephalon contains by the bilaterally paired habenular nuclei and the pineal complex, which includes the pineal gland and parapineal organ. The habenulae exhibit more or less marked left-right asymmetries among most of the major vertebrate taxa. The parapineal is also asymmetrical but it is absent in many taxa. Zebrafish is the model system for the studies of the developmental mechanisms of epithalamic asymmetries. In this species, a lateralized parapineal migration is required for the establishment of habenular asymmetries. The underlying genetic mechanisms have also been partially decrypted. The first conspicuous asymmetry in the dorsal diencephalon corresponds to a left-sided expression of components of the Nodal signalling pathway. This asymmetric Nodal signalling activity is essential to induce an early neurogenetic asymmetry but not necessary the formation of epithalamic asymmetries per se. Its role is restricted to provide a bias to the parapineal organ’s lateralized migration, and thus influence the laterality of epithalamic asymmetries. Indeed, habenular asymmetries are induced by the final position of the parapineal organ. Conservation of these mechanisms described in zebrafish across vertebrates remains an open question. During this thesis, I tried to understand the evolution of these mechanisms by studying a Chondrichthyes, the catshark Scyliorhinus canicula and cyclostomes, the lampreys Petromyzon marinus and Lampetra planeri. Their phylogenetic position and the major asymmetries in size observed between their left and right habenulae make these species good model systems to understand the origin of these mechanisms in vertebrates. My work leads to three main conclusions:(1) As in zebrafish, we have found an asymmetric expression of the components of the Nodal signalling pathway in the left dorsal diencephalon of the catshark and the lamprey. The laterality of the asymmetry is conserved between these three species, which allows us to exclude a reversed laterality in lampreys like it was proposed on the basis of arguments related to the size of habenular nuclei.(2) The Nodal signalling pathway is requied for the establishment of habenular asymmetries in the catshark and lamprey thus suggesting an ancestral role in the development of epithalamic asymmetries.(3) A detailed analysis of proliferation-differentiation patterns in the catshark habenulae during their development highlighted multiple cellular and molecular asymmetries. In particular it showed the existence of an earlier left-sided asymmetric neurogenesis.These studies provide new insights about the origin and diversification of the mechanisms controlling the establishment of vertebrates’ brain asymmetries. The study of the lamprey and the dogfish, two unconventional model systems open new perspectives for their understanding
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Ruzicka, Anna, et Michael Kjelland. « LED-lampors härdningseffekt på komposit - En laborativ studie ». Thesis, Malmö universitet, Odontologiska fakulteten (OD), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-19829.
Texte intégralRésumé :
Syfte: Att undersöka och jämföra effekten av olika LED-lampor genom mätning av konversionsgrad, härdningsdjup och mikro-hårdhet på en universal nano-komposit. Detta utifrån frågeställningarna: - Stämmer härdningslampornas verkliga irradians överens med den som uppges i produktdatabladen?- Kan härdningsprocessen effektiviseras genom att ljushärda med högre irradians och kortare härdningstid?Material & Metod: Materialegenskaperna - konversionsgrad, härdningsdjup och mikro-hårdhet mättes för kompositen Filtek Supreme XTE (3M ESPE) med fem LED-härdningslampor och olika härdningstider (kort, medellång, lång tid). LED-lamporna som användes i studien var L.E.Demetron II (Kerr), Mini LED (Satelec), D-Light Pro (GC), Epilar Deepcure-S (3M ESPE) och Flashmax P3 (CMS Dental). LED-lampornas spektralfördelning erhölls med en CCD-spektrometer (Avantes Inc.) kopplad till en integrerande sfär (Gooch & Housego) med en fiberoptisk kabel (Avantes Inc.). Data analyserades med ensidig och tvåsidig variansanalys (ANOVA-test) följt av Tukey-test. Resultat: En kort härdningstid och en härdning med låg irradians gav en lägre konversionsgrad, härdningsdjup och mikro-hårdhet jämfört med härdning med längre tid och hög irradians.Slutsats: Härdningslampornas verkliga irradians överensstämmer med irradiansen som uppges i produktdatabladen. En tillräcklig polymerisering uppnås med alla härdningslampor vid samtliga härdningstider. Härdningsprocessen kan effektiviseras och/eller förbättras genom att tillföra mer energi på kortare tid. Att förlänga härdningstiden utöver tillverkarens rekommendationer har en positiv effekt på materialegenskaperna – ökad konversionsgrad, härdningsdjup och mikro-hårdhet.Aim: To investigate and compare the effect of different LED curing devices by measuring degree of conversion, curing depth and micro-hardness of a universal nanocomposite, based on the questions:- Does the actual irradiance of the curing lamps match the one specified in the product data sheets?- Can the curing process be done more efficiently by light curing with a higher irradiance and a shorter curing time?Materials & Methods: The material properties degree of conversion, curing depth and microhardness were measured for the Filtek Supreme XTE (3M ESPE) composite with different LEDs and after curing at different curing times (short, medium, long). The light curing units used in the study were L.E.Demetron II (Kerr), Mini LED (Satelec), D-Light Pro (GC), Epilar Deepcure-S (3M ESPE) and Flashmax P3 (CMS Dental). The spectral irradiance of the LEDs was obtained with a CCD spectrometer (Avantes Inc.) connected to an integral sphere (Gooch & Housego) with a fiber optic cable (Avantes Inc.). Data were analyzed with one- and two-way ANOVA test followed by Tukey test. Results: Short curing times and low irradiance results in lower values of the material properties compared to longer curing times and higher irradiance.Conclusion: The actual irradiance of the curing lamps is consistent with that stated in the product data sheets. Sufficient polymerization was achieved with all curing lamps at all curing times. The curing process can be made more efficient and/or be improved by adding more energy in less time. Extending the curing time has a positive effect on the material properties – an increased degree of conversion, depth of cure and micro-hardness.
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Rueff, Bastien. « De la lampe à l'éclairage en Crète minoenne (3200 - 1100 av. J.-C.) ». Thesis, Paris 1, 2020. http://www.theses.fr/2020PA01H006.
Texte intégralRésumé :
Les lampes minoennes sont les seules sources de lumière artificielle à ne pas avoir été étudiées comme telles mais plutôt comme marqueurs chronologiques et régionaux. Ce travail de recherche propose une analyse fonctionnelle de ces objets, depuis la mèche jusqu’à la lumière produite et enquête, par ce prisme, sur le rythme des activités et l’espace vécu des Minoens. À cet effet, une approche interdisciplinaire a été mise en œuvre. Une analyse typo-techno-fonctionnelle a été appliquée à 543 lampes et objets ayant pu avoir un lien avec l’éclairage. Ce corpus est issu de sept sites dont la séquence chronologique couvre l’ensemble de l’âge du Bronze ; il autorise une analyse diachronique des techniques d’éclairage dans l’habitat. Le fonctionnement des lampes a été étudié dans le cadre d’un programme expérimental. Fondé sur la reconstitution du répertoire des formes, des combustibles et des mèches disponibles dans l’environnement des Minoens, il a jeté un éclairage nouveau sur les aspects techniques de leur utilisation (transport, durée de combustion, fumées, odeurs, lumière). Dans ce cadre, un référentiel de dépôts de suie a été élaboré. La forme et la texture de ces dépôts varie selon la nature des combustibles utilisés. Des enregistrements photométriques expérimentaux ont, par ailleurs, montré que les ambiances lumineuses diffèrent en fonction des combustibles utilisés. Le référentiel a donc non seulement permis d’identifier les combustibles des lampes minoennes (huiles végétales, graisses animales, cire d’abeille) mais aussi la couleur et l’intensité de leurs flammes, à partir desquels de premiers modèles en trois dimensions ont été réalisés. Une analyse spatiale des lampes dans leur contexte archéologique a, enfin, contribué à préciser le rôle de la lumière dans le rythme et la localisation des activités quotidiennes en s’appuyant, par moments, sur des analogies ethnographiques. C’est l’image d’une société préindustrielle qu’il faut avoir en tête : la journée de travail commence à l’aube et se termine au crépuscule. Son rythme et son intensité varient en fonction des saisons, de la météo et de l’altitude. Les lampes éclairaient, le soir venu, et parfois en journée, des activités collectives et individuelles, à l’extérieur ou à l’intérieur. Mais leurs flammes ne permettaient pas de voir à plus d’un mètre, ce qui suggère que l’on se déplaçait régulièrement dans le noirMinoan lamps remain the only artificial light sources that have not yet been studied as lighting devices but rather as chronological and regional markers. This research proposes a functional analysis of these objects, entailing from the wick to the light, and investigates, through this prism, the rhythm of activities and the Minoans’ lived space. To this end, an interdisciplinary approach was developed. A typo-techno-functional analysis has been applied to 543 lamps and objects that could have a link with lighting. This corpus comes from seven settlements in a chronological sequence covering the whole Bronze Age, thus permitting a diachronic analysis of lighting techniques within the sites. The function of lamps has been studied through an experimental approach. Based on the reconstruction of shapes, fuels and wicks available in the Minoans’ environment, it has shed light on technical aspects of their utilization (transport, burning length, smokes, smells, light). In this frame, a reference database of soot deposits has been designed. These deposits’ shape and texture vary according to the fuels used. Experimental photometric recordings have, besides, showcased that light ambiances differ according to the fuels. Consequently, the reference database not only helped identifying the fuels of minoan lamps (vegetal oils, animal fats, beeswax) but also their flames’ colour and intensity, based on which some first three-dimensions models have been built. A spatial analysis of lamps in their archaeological context, eventually, contributed to define the role of light on the rhythm and the localization of activities from the daily life, sometimes thanks to ethnographic analogies. This is the picture of a preindustrial society that one shall keep in mind: work starts at dawn and ends at dusk. Its rhythm and intensity vary according to seasons, weather and altitude. Lamps lighted, from the evening onwards, and sometimes during daytime, collective and individual activities, inside and outside. However, their flames didn’t permit to see beyond one meter far, suggesting that moving in the dark was common
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Benes, Jessica Anne. « The effects of axotomy on the biophysical properties of reticulospinal neurons in larval lamprey ». Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4632.
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Thesis (M.A.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 17, 2009) Includes bibliographical references.
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Johnson, Nicholas S. « In-stream behavioral responses of female sea lampreys to pheromone components ». Diss., Connect to online resource - MSU authorized users, 2008.
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Liland, Knut Brede. « Evolution transitoire d'une décharge à basse pression : application aux lampes = Transient evolution of low pressure glow discharges with application to discharge lamps ». Toulouse 3, 1997. http://www.theses.fr/1997TOU30035.
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Ce travail presente les differentes phases du fonctionnement des decharges dans les gaz (lampes): le claquage, la decharge luminescente et la transition vers l'arc thermoionique. Apres avoir presente les fondements de la physique des decharges, nous analysons les differents modeles physiques et numeriques elabores pour suivre l'evolution d'une telle decharge en fonction du temps en tenant compte de plusieurs parametres: composantes du courant, densites des especes chargees (electrons et ions) et champ electrique. Nous comparons ensuite les differents modeles (monte carlo, fluide et hybride). Dans la seconde partie, nous traiterons de l'evolution temporelle de la decharge de la phase initiale de claquage dans le gaz jusqu'a la decharge luminescente a l'etat stable. La densite de courant et des particules ainsi que le champ electrique sont etudies en fonction du temps. La pression, la tension, le circuit electrique et le materiau des electrodes constituent des parametres variables. La troisieme partie est une etude bibliographique de la transition entre une decharge luminescente et un arc thermoionique. Enfin, nous exposons les resultats de trois types d'experimentations conduites en 1995 avec philips lighting (central development laboratories), eindhoven, pay bas sur des lampes. Les resultats experimentaux sont analyses pour chacune des phases de la decharge (claquage, decharge luminescente et la transition vers l'arc thermoionique) et compares aux modeles numeriques etudies precedemment
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Martin, Holly R. « Intraspecific phylogeography of the Least brook lamprey (Lampetra aepyptera) ». Ohio : Ohio University, 2006. http://www.ohiolink.edu/etd/view.cgi?ohiou1141746230.
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Sjöberg, Kjell. « River Lamprey Lampetra fluviatilis (L.) Fishing in the Area around the Baltic Sea ». Dept. of Wildlife, Fish, and Environmental Studies, Swedish University of Agricultural Sciences (SLU), 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-52756.
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The river lamprey (Lampetra fluviatilis) was previously caught in large numbers in Europe when migrating up in the rivers during autumn for spawning the next spring. It was used as food and was also used as bait in cod fishing in the North Sea. Today the river lamprey has decreased in numbers over much of it’s distribution range, but in the Baltic Sea area, the population is still at a fairly good level, and fishing for lampreys as food (a tradition going back to at least the fifteenth century) is still going on in northern Swedish and Finnish rivers, as well as in coastal rivers in the southern Baltic Sea area. In this article the current situation as regards river lamprey fishing in Sweden, Finland, Latvia and, to some extent, Estonia, Lithuania and Poland is presented.
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Afonso, Joana de Almeida Cardoso Guimarães. « Caracterização das cultivares Lampa Preta e Pingo de Mel e influência do sistema de condução no vigor, na produção e na qualidade ». Master's thesis, ISA/UL, 2019. http://hdl.handle.net/10400.5/18398.
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Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia / ULO principal objetivo da produção de figos era a indústria do álcool e estes eram secos debaixo das figueiras, consequentemente a sua copa tinha que ser alta. A cultura da figueira sofreu um retrocesso, agravado pelo elevado custo da mão de obra, característico desta cultura, principalmente na colheita dos figos. Assim, os sistemas de condução são fundamentais para reduzir custos de produção e aumentar o rendimento/ha. Para além disso, a colheita para consumo em fresco requer várias passagens, logo a altura e forma das plantas deve ser baixa e estreita para uma colheita rápida e eficiente. Considerando estes fatores limitativos da cultura, desenvolveu-se um estudo comparativo entre os sistemas de condução (vaso baixo e eixo central revestido) no vigor, produção e qualidade, nas cultivares Lampa Preta e Pingo de Mel, em Alcobaça, com compasso de 6mx3m e regime de sequeiro. Adicionalmente, caracterizaram-se ambas as cultivares utilizando os descritores do IPGRI e estudou-se a fenologia. Para avaliar o vigor mediu-se o diâmetro do tronco e do comprimento do lançamento do ano e pesou-se a lenha de poda. Para a produção contou-se o número de figos e realizou-se a sua pesagem, em cada colheita. Para a qualidade dos figos consideraram-se parâmetros tais como peso, comprimento, calibre, comprimento do pedúnculo, dureza e teor de sólidos solúveis totais (TSS). Na ‘Pingo de Mel’ verificou-se que as figueiras em vaso são mais vigorosas e mais produtivas (12,7 kg/árvore) do que as conduzidas em eixo (6,2 kg/árvore). Verificou-se que a qualidade da produção foi pouco afetada pelo sistema de condução, excepto a dureza com 25,9 UD (vaso) e 28,9 UD (eixo) e o TSS com 21,2 ºBrix (vaso) e 21,6 ºBrix (eixo). Na ‘Lampa Preta’ a produção em ambos os sistemas de condução foi fraca (0,2 kg/árvore) e também não houve diferenças significativas na qualidade
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Hume, John B. « The evolutionary ecology of lampreys (Petromyzontiformes) ». Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4125/.
Texte intégralRésumé :
Lampreys (Petromyzontiformes) are an ancient vertebrate group, comprising 40 currently recognised species that range throughout the Northern and Southern Hemispheres. Despite a conserved morphology, lampreys nevertheless express a diverse range of life history strategies. Unusually for vertebrates larval lampreys are filter-feeding organisms prior to undergoing an extensive anatomical reorganisation, and the adoption of either a parasitic or a non-parasitic adult life. Parasitic lampreys consume the flesh and blood of actinopterygian fishes, either in marine or freshwater environments, while non-parasitic lampreys do not feed following their metamorphosis from the larval form. Morphological and genetic similarities between pairs of parasitic and non-parasitic lampreys have led to taxonomic confusion regarding the specific status of many non-parasitic forms, and the suggestion that the loss of the trophic adult phenotype is the result of a single species capable of producing alternative life history strategies. In this thesis it is argued that at least some paired species of lampreys do not comprise two distinct evolutionary lineages; rather, that non-parasitic lampreys represent one extreme in a continuum of life history variation expressed by a parasitic species. Some lamprey species, such as the European river lamprey Lampetra fluviatilis, are morphologically variable, exhibiting divergent phenotypes in response to ecological pressures, such as alternative foraging environments. Loch Lomond, Scotland contains a population of L. fluviatilis that feeds exclusively in the lake and exhibits a reduced body size and an overall morphology distinct from the typical anadromous form. Its foraging strategy indicates that it may be capable of switching hosts in the face of declining numbers of a presumed favoured and formerly abundant host, suggesting a certain amount of plasticity in its trophic ecology that may have ensured its survival in this freshwater lake. This freshwater-resident form, as well as anadromous L. fluviatilis and the non-parasitic species L. planeri, were found to spawn in a single river system within the Loch Lomond basin, and this site is crucial for the continued presence of this life history variant in Loch Lomond. The appearance of sexually mature specimens of three discrete phenotypes in this river, each representing an alternative life history strategy that may, or may not, belong to a single species, provides a crucial opportunity to test the strength of assortative mating between lamprey species pairs. Within this system the strength of assortative mating was found to be weak, and points to the possibility that freshwater-resident L. fluviatilis are mitigating gene flow between large anadromous parasitic L. fluviatilis, and small, non-parasitic L. planeri. As well as weak behavioural isolation, inter-specific sneak male mating tactics were documented among these populations, and represents the first time this phenomenon has been observed between paired lamprey species. Such behaviour indicates a lack of species-specific cues acting between L. fluviatilis and L. planeri, and suggests that hybrid offspring could be common in some systems. Testing hybrid viability (survivorship) between Loch Lomond’s two L. fluviatilis life history strategies and the sympatric L. planeri revealed no post-zygotic barriers to gene flow, at least in the form of gamete incompatibility. Perhaps more convincingly though, when comparing traditional morphometrics and body shape variation, as well as mitochondrial DNA sequences, between L. fluviatilis expressing different foraging strategies with populations of L. planeri, no robust species specific differentiation was observed. In fact, species delimitation between L. fluviatilis and L. planeri appears to be related solely to overall body size, which is itself a function of life history strategy. However, life history strategy was not correlated with current species designation as relationships among mtDNA haplotypes indicate non-parasitic populations have evolved independently multiple times throughout the geographic range of L. fluviatilis in Europe. Therefore, L. planeri should not be considered as a distinct species, either morphologically or genetically. Instead, L. fluviatilis appears capable of expressing a range of life history strategies; from parasitic anadromous populations through to non-parasitic stream-resident populations. The overall research approach employed in this thesis, i.e., the combination of ecological, behavioural, taxonomic and molecular studies, could be used to robustly examine the evolutionary ecology of parasitic and non-parasitic lampreys elsewhere.
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Campo-Paysaa, Florent. « Evolution du développement chez les Chordés : une histoire d'acide rétinoïque, de gènes hox et de microARNs ». Thesis, Lyon, École normale supérieure, 2011. http://www.theses.fr/2011ENSL0653.
Texte intégralRésumé :
Le but de toute étude en biologie évolutive du développement est l’étude des mécanismes développementaux à l’origine des diversifications morphologiques. Dans ce contexte, j’ai décidé de me focaliser sur l’émergence des Vertébrés au cours de l’évolution, par la mise en œuvre d’études comparatives entre différents modèles de Deutérostomiens. Le travail réalisé durant ma thèse est subdivisé en trois projets: (i) j’ai abordé le lien entre l’évolution du cerveau chez les Chordés et les modifications de la signalisation à l’acide rétinoïque (AR) au cours du développement. En particulier, j’ai examiné les rôles de l’AR au cours du développement du cerveau chez la lamproie Lampetra fluviatilis, et j’ai comparé les résultats obtenus chez cette espèce aux mécanismes développementaux agissant chez l’amphioxus, un Chordé invertébré, et chez les modèles gnathostomes classiques. Les données obtenues lors de ces analyses comparatives ont permis une meilleure compréhension de l’évolution de la régionalisation cérébrale chez les Vertébrés. (ii) j’ai étudié l’évolution des séquences régulatrices présentes au sein des clusters de gènes hox, connus pour agir dans la régionalisation du système nerveux des Chordés. L’identification d’éléments non-codants conservés ainsi que d’éléments de réponse à l’AR (RARE) potentiels dans des clusters hox de Chordés, combinée à la caractérisation de RAREs in vivo en cellules murines a permis une vision intégrée de l’évolution du contrôle des gènes hox par l’AR, chez les Chordés. (iii) j’ai analysé l’évolution des microARNs chez les Chordés en comparant les répertoires microARN chez plusieurs espèces de Deutérostomiens. Cette étude a permis d’émettre de nouvelles hypothèses quant à l’émergence des microARNs chez les animaux. Toutes ces analyses ont abordé différents aspects de l’évolution des Chordés avec pour objectif la proposition d’une vision intégrée des mécanismes moléculaires à l’origine de l’émergence des VertébrésThe aim of the evolutionary developmental biology is to study the developmental mechanisms at the base of morphological diversification. In this context, I decided to focus my attention on the emergence of vertebrates during evolution by carrying out comparative analyses in several deuterostome models. The work carried out during of my thesis can be subdivided into three major projects: (i) I addressed the link between brain evolution and modifications in retinoic acid (RA) signaling during chordate development. In particular, I investigated the roles of RA signaling in brain development in a jawless vertebrate, the lamprey Lampetra fluviatilis, and compared the results with developmental mechanisms in the invertebrate chordate amphioxus and classical developmental model systems in jawed vertebrates. Data obtained from these comparative studies provided insights into the evolution of brain patterning in vertebrate evolution. (ii) I investigated the evolution of the regulatory landscape of hox gene clusters that are known to be fundamental for the patterning of the chordate central nervous system. The identification of conserved non-coding elements and putative RA response elements (RAREs) in hox clusters of different chordate species combined with the in vivo characterization of functional RAREs in mouse F9 cells provided an integrated view of the evolution of RA-dependent hox cluster regulation in chordates. (iii) I studied the roles of microRNAs (miRNAs) in chordate evolution by comparing the miRNA complements of different deuterostome species. This analysis provided novel insights about the general mechanisms of miRNA emergence in animals and highlighted species-specific miRNA complement amplifications in different deuterostome lineages. In sum, these studies have tackled different aspects of chordate evolution from an evo-devo perspective, aiming at an integrated view of the molecular mechanisms underlying vertebrate diversification
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Huss, Mikael. « Computational models of lamprey locomotor network neurons ». Licentiate thesis, Stockholm : KTH Numerical Analysis and Computer Science, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-304.
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Pavlova, Elena. « Vestibular control of body orientation in lamprey / ». Stockholm, 2004. http://diss.kib.ki.se/2004/91-7349-861-0/.
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Alder, Matthew N. « The adaptive immune system of sea lamprey ». Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2009r/alder.pdf.
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Eckardt, Hella. « Illuminating Roman Britain / ». Montagnac : M. Mergoil, 2002. http://catalogue.bnf.fr/ark:/12148/cb39007842f.
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Smith, Dustin M. « Habitat selection and predation risk in larval lampreys ». Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10493.
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Ryan, Sarah Kathleen. « Glutamate regulates neurite outgrowth of descending neurons in culture from larval lamprey ». Diss., Columbia, Mo. : University of Missouri-Columbia, 2005. http://hdl.handle.net/10355/4231.
Texte intégralRésumé :
Thesis (M.S.)--University of Missouri-Columbia, 2005.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (December 19, 2006) Vita. Includes bibliographical references.
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Thoday, A. « Studies on the ultrastructure of the pituitary of a non parasitic lamprey Lampetra planeri throughout the larval, metamorphosing and adult stages ». Thesis, Open University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380056.
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Östling, Johan. « Effekt och Lumen mätning av LED lampor ». Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-369726.
Texte intégralRésumé :
I denna rapport undersökts effect förbrukning och uppmätt antal Lumen för en rad olika LED-lampor, reslutatet jämförs sedan med specifikationerna för respektive lampa. Slutsatsen är att även fast det är problematiskt att mäta antalet Lumen från en lampa, så går det att uppvisa liknande resultat som förpackningen påvisar. Effektförbruknings mätningar har mindre felkällor vilket ger ett noggrannare resultat.
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Pflieger, Jean-François. « Organisation du système vestibulaire chez la lamproie, Petromyzon marinus ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0017/NQ47635.pdf.
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Islam, Salma Sanzida. « Analysis of different forms of locomotor behavior in lamprey / ». Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-185-2/.
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Cangiano, Lorenzo. « Mechanisms of rhythm generation in the lamprey locomotor network / ». Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-042-7/.
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Jia, Yan. « Computer simulation of the lamprey spinal cord locomotor system ». Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610128.
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Gilbey, Thomas James. « Investigations into synaptic modulation in the lamprey spinal cord ». Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611625.
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Denani, Gustavo Henrique Soares. « Lampejos da percepção : jogos digitais em tempos de biopolítica ». Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/27/27161/tde-01022017-105734/.
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Esta pesquisa tem como escopo geral um fenômeno que articula espetáculo e jogos digitais, chamado de eSport. Trata-se de uma cena competitiva de jogos digitais, composta de torneios, partidas transmitidas online e ao vivo para milhares de espectadores, além de patrocinadores e rotinas de treinamento. Dependendo do jogo em questão, diferentes competências são exigidas para um desempenho vitorioso, como reflexos rápidos, leitura e interpretação de informações que emergem durante uma partida, e comunicação para a coordenação de um time. Sobretudo, é uma expressão cultural que reverbera em aspectos sociais e tecnológicos diversos, sendo que interessa aqui deter-se sobre a subjetivação acerca dos jogadores quando se leva em conta os algoritmos de um jogo digital (o audiovisual produzido por eles, compondo espacialidades diversas, e as regras, que moldam a temporalidade de uma sessão de jogo). Argumenta-se que os jogadores, de modo geral, integram uma densa máquina social e tecnológica, onde a produção de mercadoria e de subjetividades acontece tanto na aquisição de periféricos e jogos quanto na própria atividade que engendra o jogo. Essa máquina se faz mais visível no nicho dos eSports, onde exploramse as lógicas que compõem o jogo e as capacidades do jogador. Entre as rotinas de treinamento dos jogadores profissionais e o parâmetro intangível que decide o sucesso de um jogo, a diversão, há uma zona cinzenta, já evidente em técnicas de gamification, onde atividade laboral e entretenimento embaralham-se. Daí a necessidade de se abordar criticamente que tipo de usuário resulta dessa relação específica com as tecnologias envolvidas em jogos digitais.The scope of this research is a phenomenon that articulates spectacle and digital games, called eSport. eSport is a competitive scene comprising digital games, championships, sponsors, training routines and matches transmitted online and live to a crowd of hundreds of thousands. Depending on the game, different skills are required to achieve a competitive performance, such as sharp reflex, reading and interpretation of information that emerges during a match, and communication to ensure the team\'s coordination. Above all, it is a cultural expression that echoes in a multitude of social and technological aspects, emphasizing here the subjectivation of the players, considering the algorithms (that is, the audiovisual produced by them and the rules, that shape the temporality of a game session) that compose them. It argues that the players, broadly speaking, are part of a dense social and technological machine, where the production of commodities and subjectivities happens when someone purchases equipments and digital games, but also during and within the very activity that comprises the game.This machine makes itself more visible at the eSports niche, where the logics that compose the game and the capacities of the player are exploited. Between the training routines and the intangible parameter which decides the success of the game, called fun, there is a grey area, clear enough in gamification techniques, where labor and entertainment are shuffled. Hence the need to critically engage the type of user that results from this specific relation with technologies involved in digital games.
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Martin, Holly Renee. « Intraspecific Phylogeography of the Least Brook Lamprey, (Lampetra aepyptera) ». Ohio University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1141746230.
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Zhang, Lei. « Axonal regeneration of descending brain neurons in larval lamprey / ». free to MU campus, to others for purchase, 1999. http://wwwlib.umi.com/cr/mo/fullcit?p9964016.
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Neira, Francisco Javier. « Systematics and ecology of larvae of lampreys and fishes ». Thesis, Neira, Francisco Javier (1988) Systematics and ecology of larvae of lampreys and fishes. PhD thesis, Murdoch University, 1988. https://researchrepository.murdoch.edu.au/id/eprint/53025/.
Texte intégralRésumé :
Body intervals, number of trunk myomeres and frequency of pigmentation in different body regions were recorded for populations of larvae of each of the three Southern Hemisphere anadromous parasitic lampreys collected from rivers in Australia, New Zealand and South America. In order to correct for growth, the morphometric data were subjected to multiple group principal components analysis (MGPCA). The components, together with myomere counts and pigmentation data, were subjected to discriminant analyses. Clustering of the discriminant centroids clearly distinguished between populations of Mordacia lapicida from Chile and those of Mordacia mordax from south-eastern Australia. Comparable analyses for Geotria australis suggest that during their marine trophic phase, the adults of this species originating from Argentina and Chile follow different migratory routes, whereas those from Western Australia, New Zealand and Tasmania intermix.
A total of 65,253 larval fish, representing 36 families and 70 species, were collected from surface waters throughout the Swan Estuary between January 1986 and April 1987. Density of many of the most abundant species reached a peak between November and January. The most abundant families were the Gobiidae (88.5%), Clupeidae (3. 5%), Engraulidae (2.3%) and Blenniidae (1.0%). The abundance and distribution of larvae of Nematalosa vlaminghi, Engraulis australis, Parablennius basmanianus, Urocampus carinirosbris, Apoqon rueppellii Atherinosoma wallacei and Amniataba caudavittatus indicate that these species spawn in the upper and/or middle estuary, whereas species such as Hyperlophus vittatus, Parapercis haackei, Callionymus qoodladi and Pelates sexlineabus typically spawn in the lower estuary. Larvae in the lower estuary belonged predominantly to marine species (60%) whose adults are infrequently found in the estuary and to those species which use estuaries and inshore-marine areas as nurseries (21.4%). Although the larvae in the middle and upper estuary represented a small number of species which typically breed within the estuary (14.3%), they accounted for 91.1% of all larvae caught in the estuary. While number of species, diversity and evenness decreased with distance from estuary mouth, the density of larvae was greatest in the upper estuary. The relationships between the above community variables and environmental variables are discussed.
Studies on the early life history of five species from the Swan Estuary indicate that the development of larval Atherinosoma wallacei, Ammniataba caudavitattus and Apogon rueppellii takes place predominantly in the upper estuary between mid-spring and early autumn, whereas that of Gymnapistes marmoratus and Lesueurina sp. occurs in the lower estuary between winter and early spring. While the larvae of all these species are pelagic, they show a variety of developmental and morphological characters which may facilitate their survival and retention within the estuary. These include a large swim bladder and dark body pigment (A. wallacei), extensive head spination and early development of large pectoral fins (G. marmoratus), rapid settlement (A. caudavittatus and G. marmoratus), an advanced stage of development at hatching (A. rueppellii) and an elongated body (Lesueurina sp.).
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Mahmody, Susan. « Hubert Lampo - Franz Kafka : Wechselbeziehungen / ». Marburg : Tectum-Verlag, 2008. http://opac.nebis.ch/cgi-bin/showAbstract.pl?u20=9783828896918.
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Buckley, Alastair. « Laser diagnostics of discharge lamps ». Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322979.
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Mahmody, Susan. « Hubert Lampo - Franz Kafka Wechselbeziehungen ». Marburg Tectum-Verl, 2005. http://d-nb.info/989861368/04.
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Trost, Catherine. « Recherches sur les lampes chrétiennes en terre cuite : contribution au catalogue des lampes antiques de la Bibliothèque nationale de France ». Paris 4, 1994. http://www.theses.fr/1994PA040340.
Texte intégralRésumé :
Ce travail est une contribution au troisième tome du catalogue des lampes antiques de la bibliothèque nationale de France. Il comporte deux cents lampes en terre cuite, en majorité de l’époque paléochrétienne (4e-7e siècle après j. -c. ) et quelques exemplaires très tardifs, voire de l'époque médiévale (dont une lampe arabe). Les lampes chrétiennes d’Afrique du nord en sigillée (types Hayes I et II) forment la partie principale, avec cent quarante-huit numéros, plus deux moules en platre. Le reste de la collection comporte des lampes diverses : autres lampes d’Afrique du nord (lampes dites "tripolitaines" et "vandales"), lampes syro-palestiniennes, siciliennes etc. . . Ainsi que trois lampes modernes (reproductions ? Faux ?). Chaque section du catalogue est précédée d'une présentation typologique et chronologique. Enfin, un nouveau répertoire des motifs du bandeau des lampes de type Hayes II a été ajouté. Il est conçu comme un système ouvert permettant des enrichissements ultérieurs. La synthèse concerne les lampes chrétiennes d’Afrique du nord. Elle fait le point sur l'histoire de la recherche, le contexte économique et industriel, la datation, la diffusion, les ateliers, la fabrication, le décorThis work is a contribution to the third volume of the catalogue of antique lamps in the National library of France. It is composed of two hundred terracotta lamps, mostly belonging to the early Christian era (4th to 7th century a. D. ), and a few later copies as far as the medieval era - among them and Arabian lamp-. The early Christian lamps of African red slip ware (Hayes type 1 and Hayes type 2), from Tunisia, amount to the most important part with 148 items, plus 2 plaster moulds. The rest of the collection is composed of various lamps: other lamps from North Africa, called "tripolitanian" and "vandal", syr-palestinian lamps, Sicilian lamps etc. . . As well as 3 modern lamps -maybe forged-. Each section of the catalogue is preceded by a typological and chronological presentation. A new index of the decorative patterns in the irms of Hayes type 2 lamps has also been added. It has been thought of as an open composition allowing future developments. The synthesis is about the early Christian lamps from north Africa. It tries to picture the present state of knowledge about the history of research, the economical and industrial context, the datation, the distribution, the workshops, the manufacture, the decoration
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Koprnicky, Jan. « Modèles de conductivité électrique pour lampes à décharge ». Toulouse 3, 2008. http://thesesups.ups-tlse.fr/171/.
Texte intégralRésumé :
Cette thèse de doctorat est consacrée à la modélisation de décharges luminescentes pour la description de circuits électriques. L'objet n'est pas la modélisation du comportement interne d'un plasma, mais de sa conductivité équivalente. Les paramètres de la conductivité sont déterminés à partir des caractéristiques de tension et de courant de lampes à décharges. Ce modèle ne requiert aucune donnée technologiques de la part des fabricants de lampe. L'environnement Matlab/Matlab Simulink est utilisé pour le traitement de u(t); i(t), l'exécution des algorithmes d'identification et la simulation en termes de circuits électriques équivalents. Les résultats des simulations sont comparés avec les données mesurées. Le modèle de conductance est testé dans des simulations de lampes à décharge à basse et haute pression, alimentées par ballast magnétiqueThis Ph. D. Thesis deals with light discharges modelling for description of electric circuits. It is not modelling of internal behaviour of a plasma, but its equivalent conductivity. The parameters of conductivity model are determined from measured voltage and current characteristics of discharge lamps. This model does not require any technological data from lamp producers. The Matlab/Matlab Simulink is used for data processing of u(t); i(t), application of identification algorithms and electric circuits simulation. The simulated results are compared with measurements. The model is tested in simulations of low and high pressure discharge lamps in circuits with magnetic ballasts
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Albou, Pierre. « De l'alimentation des lampes à décharge pour l'automobile ». Paris 6, 1991. http://www.theses.fr/1991PA066398.
Texte intégralRésumé :
L'utilisation de lampes a décharge pour l'éclairage automobile présente de nombreux avantages. Une famille de lampes a arc spécialement destinées a cet usage a été récemment mise au point. Les lampes de cette famille (lampe d1) ont des caractéristiques particulières. Ces caractéristiques font de ces lampes des sources de lumière très performantes mais difficiles a alimenter. Après avoir montre que les modèles d'arc courants sont de peu d'utilité dans le cadre de cette étude et que les structures de convertisseurs usuellement employées pour l'alimentation des lampes a arc ne permettent pas de respecter les contraintes imposées par l'industrie automobile, nous présentons deux nouvelles structures d'onduleurs bien adaptées a l'alimentation des lampes d1, ainsi que la démarche qui nous a conduit a ces montages. Ces convertisseurs mettent en ouvre les concepts de quasi et de multi-resonance. Pour chacun de ces convertisseurs, nous analysons de manière théorique le fonctionnement du montage et nous présentons des résultats expérimentaux obtenus a l'aide de plusieurs prototypes
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Rai, Satbir Kaur. « Identification of a putative corticosteroid in Pacific Lamprey (Entosphenus tridentatus) ». Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/51677.
Texte intégralRésumé :
The mechanisms and interplay of multiple axes as well as the physiological components of the stress response have been studied in many vertebrate groups; however, the intricacies and chemical messengers involved in the stress response in lamprey have not been fully resolved. 11-Deoxycortisol is a functional corticosteroid in sea lamprey, but the identity of the functional corticosteroid used by other lamprey species and the evolution of the stress response in lamprey lineage remains unknown. Identification of the functional corticosteroid in a greater number of lamprey species will help elucidate the evolution of the stress response in lamprey. I have demonstrated that 11-deoxycortisol, a steroid precursor to cortisol, may be a functional corticosteroid in Pacific lamprey. The putative hormone was identified in Pacific lamprey plasma by employing an array of methods such as radioimmunoassay (RIA), high performance liquid chromatography (HPLC) and mass spectrometry analysis. I have demonstrated that plasma levels of 11-deoxycortisol significantly increased in Pacific lamprey 0.5 and 1 hr after stress exposure and that sea lamprey corticotropin releasing hormone (CRH) injections increased circulating levels of 11-deoxycortisol, suggesting that 11-deoxycortisol secretion is under control of the hypothalamic neuropeptide CRH. However, plasma 11-deoxycortisol concentrations did not increase in response to sea lamprey adrenocorticotropic hormone (ACTH) injections. The effect of artificially elevated 11-deoxycortisol on the expression of glucocorticoid receptor and progesterone receptor mRNA was examined in liver, gill, muscle, heart and testis using RT-qPCR. 11-Deoxycortisol was chronically elevated using coconut oil implants with two different doses of 11-deoxycortisol (0.5 and 1.0 µg per g of body weight). After 7 days of elevated plasma 11-deoxycortisol concentrations there was no significant difference in the expression of either receptor in the tissues examined. Overall, the results of this thesis demonstrate 11-deoxycortisol is a putative corticosteroid in Pacific lamprey; however, despite the evidence for hypothalamic control of 11-deoxycortisol release, the results do not conclusively support Pacific lamprey having a hypothalamic pituitary interrenal (HPI) axis.Science, Faculty of
Zoology, Department of
Graduate
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Maurya, Ashish K. « Regulatory mechanisms controlling distal-less related gene expression in lamprey ». Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27391.
Texte intégralRésumé :
Vertebrate Dlx genes code for homeodomain (a conserved DNA binding domain) transcription factors involved in the development of the forebrain, craniofacial skeleton, dentition, sensory organs and limbs. Vertebrates have at least 6 Dlx genes whereas invertebrates have only one Dlx homologue (called the distal-less or Dll gene) (Stock, Ellies et al. 1996). Vertebrate Dlx genes are organized as pairs of convergently transcribed genes. The intergenic region between each of these bigenes contains at least two highly conserved sequences (300-500bp each) that act as enhancers of transcription of the flanking Dlx genes. Activity of these enhancers when tested with reporter genes (GFP and LacZ) in transgenic zebrafish and mice recapitulates the endogenous Dlx expression patterns.
Here we are investigating Dlx regulation in lamprey, an agnathan species and a sister group of gnathostomes. In doing this we hope to (1) trace back the origin of the conserved Dlx intergenic enhancers found in vertebrates and (2) address the question, can the differences in regulation of lamprey Dlx genes with that of gnathostomes account for some of the morphological differences seen in lampreys (like absence of jaws)?
We have shown that lamprey have at least four Dlx genes (A, B, C, D), two of which are arranged in the bigenic configuration seen in other vertebrates. We were unable to find the presence of the conserved intergenic enhancers by Southern hybridization and PCR experiments within this lamprey Dlx intergenic region. We have shown that this region can target expression of reporter genes in the forebrain, branchial arches and trunk somites when tested in zebrafish embryos in a reporter gene assay, suggesting many of the Dlx regulatory mechanisms are conserved between lamprey and gnathostomes.
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Cooke, R. M. « Behavioural recovery and adaptive plasticity after spinal transection in lamprey ». Thesis, University of Cambridge, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597937.
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As in mammalian systems, the analysis of functional recovery in the lamprey has focused on regrowth of axons across lesion sites. However, there is evidence that regrowth alone cannot account for recovery. A complementary approach is to investigate how plasticity may alter network properties to optimise function below lesion sites after injury. This project has focused on examining changes in cellular and synaptic properties below lesion sites. A potential role for adaptive plasticity was initially examined after pharmacological disruption of network function for 24hrs to block action potential propagation, ionotropic glutamate receptors, or depolarise the membrane potential. In the second study, the spinal cords of lamprey were transected at 25% body length. These animals consistently recovered near-normal levels of locomotor function by 10 weeks post-transection. Several alterations in the physiological properties of spinal neurons occurred following pharmacological disruption. Adaptive changes were seen in cellular and synaptic properties, and in synaptic ultrastructure in the sublesional spinal circuitry following functional recovery. This implies that spinal networks can be altered in adaptive ways in response to extreme functional changes, and suggests a potential role for homeostatic plasticity as an accompanying mechanism to axonal regeneration in the recovery of locomotor function. This could ultimately suggest that drug treatments used in patients to suppress increased activity in the lesioned spinal cord may not be helpful, and could encourage treatments that take advantage of rather than suppress the plastic changes in activity.
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Goodwin, C. E. « The ecology of three species of lamprey in Northern Ireland ». Thesis, Queen's University Belfast, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.411223.
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Wolfe, Tobie Dianne Burks. « Studies of sea lamprey (Petromyzon marinus) reproduction and sterility assessment ». The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1303144907.
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Körberg, Johanna. « Takkronan Flamenco ». Thesis, Konstfack, Inredningsarkitektur & ; Möbeldesign, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-2726.
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Mitt magisterarbete i inredningsarkitektur och möbeldesign på Konstfack handlar om rum, ljus och skugga. Som magisterarbete har jag formgett en takkrona. Mitt projekt har varit ett experiment med ljus och skuggspel och en utmaning att förena funktion, formgivning, material och teknik.Master / InSpace 2009
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Heimerl, Andreas. « Die römischen Lampen aus Pergamon : vom Beginn der Kaiserzeit bis zum Ende des 4. Jhs. n. Chr. / ». Berlin ; New york : W ; de Gruyter, 2001. http://catalogue.bnf.fr/ark:/12148/cb38852906x.
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Rougemont, Quentin. « Évolution de la divergence entre la lamproie fluviatile (Lampetra fluviatilis) et la lamproie deplaner (Lampetra planeri) inférée par approches expérimentales et de génomique des populations ». Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S141/document.
Texte intégralRésumé :
Cette thèse étudie le processus de spéciation entre la lamproie fluviatile (Lampetra fluviatilis) et la lamproie de Planer (L. planeri). Les deux espèces présentent des stratégies d'histoire de vie extrêmement différentes : L. fluviatilis est parasite et anadrome alors que L. planeri n'est pas parasite et reste strictement dulcicole. Toutefois, leur degré d'isolement reproducteur et leur histoire de divergence demeurent méconnus. Ces questions ont été abordées par des approches expérimentales, de génomique de populations et de simulations démographiques. Des croisements expérimentaux ont révélé un faible isolement reproducteur, confirmé par des degrés variables de flux géniques dans les populations naturelles. Les analyses génétiques ont montré que les deux taxons représentaient probablement des écotypes avec un isolement reproducteur partiel suggérant que les barrières reproductives endogènes ne réduisaient que partiellement la migration efficace entre écotypes. L'importance du contexte géographique actuel et passé dans l'étude de la spéciation a aussi été mise en évidence par des analyses à l'échelle du génome. Ainsi, les populations isolées de L. planeri évoluent principalement sous l'effet de la dérive génétique et ont une diversité réduite. Les inférences démographiques ont suggéré que la divergence a été initiée en allopatrie puis suivie de contacts secondaires résultant en un parallélisme génomique partiel entre réplicas de paires de populations. Une hétérogénéité de la divergence génomique a démontré que les ilots génomiques de différenciation ne résultaient pas de l'action récente de la divergence écologique. En outre, nos résultats suggèrent un impact faible de la fragmentation anthropique des cours d'eau sur la diversité génétique des populations de L. planeri. Les populations résidentes possèdent une diversité génétique plus grande lorsque le flux de gènes avec L. fluviatilis dans les parties aval des cours d'eau. Globalement cette thèse a démontré que les paires d'écotypes parasites et non-parasites de lamproies représentent un excellent modèle d'étude de la spéciation et notamment de l'architecture génomique de la divergenceThis thesis investigates the process of speciation between the European lampreys Lampetra fluviatilis and L. planeri. The two species have drastically different life history strategies: L. fluviatilis is parasitic and anadromous while L. planeri is non-parasitic and strictly freshwater resident. Yet their level of reproductive isolation and history of divergence remain poorly understood. A multidisciplinary approach including experiments, population genomics analyses and historical reconstruction was undertaken to address these issues. Experimental crosses revealed a very low level of reproductive isolation, partially mirrored by variable levels of gene flow in wild populations. Genetic analyses revealed that the two taxa were best described as partially reproductively isolated ecotypes suggesting that endogenous genetic barriers partially reduced effective migration between ecotypes. Genome wide analyses showed the importance of the current and ancient geographical context of speciation. In particular, parapatric L. planeri populations diverged mostly through drift and displayed a reduced genetic diversity . Demographic inferences suggested that divergence have likely emerged in allopatry and then secondary contacts resulted in partial parallelism between replicate population pairs. A strong heterogeneity of divergence across the genome was revealed by sympatric populations suggesting that genomic islands of differentiation were not linked to ongoing ecological divergence. Further investigations showed that the genetic diversity of L. planeri populations was weakly affected by human-induced river fragmentation. Resident populations displayed a higher diversity when gene flow was possible with L. fluviatilis populations in downstream sections of rivers. Overall this thesis showed that parasitic and non-parasitic lamprey ecotypes represent a promising model for studying speciation and notably the genomic architecture of divergence
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Mahouche, Mohamed. « Étude en immunofluorescence et immunohistochimie des systèmes a monoamines dans le névraxe d'un cyclostome (lampetra fluviatilis) : Approche évolutive ». Paris, Muséum national d'histoire naturelle, 1998. http://www.theses.fr/1998MNHN0009.
Texte intégralRésumé :
Le but de cette étude a été d'analyser, par le biais d'une approche immunohistochimie et en immunofluorescence, les systèmes a monoamines dans le névraxe d'un agnathe actuel (lampetra fluviatilis). Ce travail constitue la première description exhaustive de ces systèmes chez les agnathes. L’analyse comparative de nos données avec celles de la littérature concernant les gnathostomes révèle que, quelles que soient les espèces considérées et leur position dans la phylogénie, le système à sérotonine apparait dans son ensemble construit selon un même plan d'organisation. De plus, cette analyse indique qu'au cours de l'évolution, les ensembles neuronaux à sérotonine régressent au niveau diencéphalique pour se complexifier au niveau rhombencephalique. Les systèmes à catécholamines chez Lampetra fluviatilis ont été, dans un premier temps, analyses par les méthodes de chromatographie liquide à haute pression (HPLC). Il a été ainsi montre que le névraxe de lampetra fluviatilis comporte une forte concentration de dopamine, de faibles traces d'adrénaline et l'absence de noradrénaline. Dans son ensemble, le plan d'organisation du système a dopamine du cerveau de lampetra fluviatilis montre des similitudes mais aussi des différences avec celui des gnathostomes. Ainsi chez la lamproie, le plus grand nombre de cellules DA-ir s'observe dans l'hypothalamus, ce qui est également le cas pour les poissons et les amphibiens. A l'inverse, il n'existe, chez la lamproie, aucun neurone DA-ir dans le tegmentum mesencephali, alors que ce type de neurone forme dans cette région une population très importante chez les amniotes. Chez les lamproies et les téléostéens, le nombre de cellules en contact avec le liquide céphalo-rachidien est important au niveau hypothalamique, alors que les cellules « D » y sont absentes. Un phénomène inverse est observé chez les mammifères.
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Jackson, Adam Wesley. « Organization of brain and spinal cord locomotor networks in larval lamprey ». Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4481.
Texte intégralRésumé :
Thesis (Ph.D.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 27, 2009) Vita. Includes bibliographical references.
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Hagevik, André. « Brainstem and spinal cord mechanisms that control locomotor activity in larval lamprey / ». free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9842533.
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Beames, Hugh. « Ancient lamps in the Nicholson Museum ». Thesis, The University of Sydney, 2004. http://hdl.handle.net/2123/19597.
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