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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.
401

Approaches to detect and classify Megavirales / Méthodes de dépistage et de classification des mégavirales

Sharma, Vikas 23 October 2015 (has links)
Les Megavirales appartiennent à des familles de virus géants infectant un grand nombre d'hôtes eucaryotes. Leurs génomes ont des tailles variant de 100 kb to 2.5 mb et leur composition a montré des caractéristiques surprenantes qui ont soulevées diverses questions sur l’origine et l’évolution de ces virus. Les études de métagénomique environnementale ont montré qu’il existe une «matière noire», composée de séquences reliées à aucun organisme connu. Cependant, l'identification des séquences a été principalement réalisée en utilisant les séquences ADN ribosomal (ADNr), ce qui conduit à ignorer les virus. D’autres gènes informationnels « cœur », incluant la DNA-dependant RNA polymerase (RNAP) constituent d'autres marqueurs qui apparaissent comme plus appropriés pour une classification plus exhaustive des séquences, puisqu’ils apparaissent conservés dans les organismes cellulaires ainsi que les mégavirus. Nous avons utilisé un petit ensemble de gènes universels conservés incluant la RNAP et avons reconstruit des séquences ancestrales pour rechercher des séquences reliées aux mégavirus dans les bases de données. Cela a permis d’identifier trois nouvelles séquences de megavirus qui avaient été mal annotées comme correspondant à des organismes cellulaires, ainsi que de nouveaux clades viraux dans les bases métagénomiques environnementales. De plus, nous avons montré que l’ordre Megavirales constituait une quatrième branche monophylogénétique ou « TRUC » (pour Things Resisting Uncompleted Classification). Nos analyses montrent également que la RNAP ainsi que quelques autres gènes utilisés dans nos études permettent de considérer un répertoire plus complet d’organismes que l’ADNr. / Nucleocytoplasmic large DNA viruses (NCLDVs), or representatives of order Megavirales, belong to families of giant viruses that infect a large number of eukaryotic hosts. These viruses genomes size ranges from 100 kb to 2.5 mb and compose surprising features, which raised various questions about their origin and evolution. Environmental metagenomic studies showed that there is a “dark matter”, composed of sequences not linked to any known organism. However sequence identification was mainly determined using ribosomal DNA (rDNA) sequences, which led therefore to ignore viruses, because they are devoid of such genes. Informational genes, including DNA-dependant RNA polymerase (RNAP), are other markers that appear as more appropriate for a comprehensive classification as they are conserved in cellular organisms (Bacteria, Archaea and Eukarya) and in Megavirales. We used a small set of universally conserved genes that included RNAP and reconstructed ancestral sequences to search for megavirus relatives in sequence databases and to perform phylogeny reconstructions. This allowed identified three megaviral sequences that were misannotated as cellular orgainsms, and new viral clades in environmental databases. In addition, we delineated Megavirales as a fourth monophylogenetic TRUC (things resisting uncompleted classification) aside cellular organisms. Moreover, we classified by phylogenetic and phyletic analyses based on informational genes new giant viruses as new bona fide members of the fourth TRUC. Our analyses shows that RNAP as well as a few other genes used in our studies allow a more comprehensive overview and classification of the biological diversity than rDNA.
402

Organisms associated with amoebae infection / Organismes associés à l'infection des amibes

Bajrai, Leena 13 March 2017 (has links)
Cette thèse présente nouveaux organismes trouvés dans d'échantillons d'eaux usées proviennent la zone sud de Jeddah, en Arabie Saoudite. Legionella saoudiensis, Kaumoebavirus, moumouvirus saoudien (SDMV), Yasminevirus et Bunga messiliensis qui sont isolés par une méthode de co-culture amibienne d'infection par Dictyostelium discoideum ATCC 44841, Vermamoeba vermiformis CDC-19, Acanthamoeba polyphaga Linc AP-1 , et Acanthamoeba griffinii, respectivement. Legionella saoudiensis, une souche bactérienne Gram-négative, en forme de bacille, LS-1T appartient au genre Legionella de la famille des Legionellaceae, basée sur des séquences de gène 16S rRNA et d'autres 4 gènes (mip, rpoB, rnpB et 23S-5S). D'une part, le KAUmoebavirus a des capsides icosaédriques de ~ 250 nm-large, un génome d'ADN de 350 731 pb, et une densité de codage de 86%, correspondant à 465 gènes. La plupart de ces gènes (59%) sont étroitement liés aux gènes de Faustoviruses (43%) et Asfarviruses (23%). D'autre part, le moumouvirus saoudien est un nouveau virus géant appartenant à la lignée Mimivirus B, de l'hôpital universitaire King Abdulaziz à Djeddah, et a présenté des particules icosaédriques de 500 nm avec un génome de 1 046 087 pb, plus grand que les génomes moumouvirus qui ont été décrites dans le passé. Il a été prédit que son génome code pour 868 ORF, dont la taille varie de 54 à 2 914 acides aminés. En outre, il code pour 40 nouveaux gènes (ORFans) sans similitude avec d'autres séquences. Ces résultats montrent que la dispositiond’une carte élargie des protistes conduit à découvrir de nouveaux virus géants. / This thesis displays novel organisms that are found in sewage water samples from southern area of Jeddah, Saudi Arabia. These organisms are Legionella saoudiensis, Kaumoebavirus, Saudi moumouvirus (SDMV), Yasminevirus, and Bung messiliensis that are isolated by amoebal co-culture method of infection with Dictyostelium discoideum ATCC 44841, Vermamoeba vermiformis CDC-19, Acanthamoeba polyphaga Linc AP-1, and Acanthamoeba griffinii, respectively. Legionella saoudiensis, a Gram-negative, bacilli shaped bacterial strain, LS-1T belongs to the genus Legionella in the family Legionellaceae based on 16S rRNA gene sequences and other 4 genes (mip, rpoB, rnpB, and 23S-5S). On one hand, KAUmoebavirus has ~250-nm-large icosahedral capsids, a 350,731 bp DNA genome, and a coding density of 86%, corresponding to 465 genes. Most of these genes (59%) are closely related to genes from Faustoviruses (43%) and Asfarviruses (23%). On the other hand, Saudi moumouvirus is a new giant virus belonging to Mimivirus lineage B, from the King Abdulaziz University hospital in Jeddah, and presented 500 nm icosahedral particles with a 1,046,087 bp genome, which is larger than moumouvirus-like genomes which have been described in the past. Its genome was predicted to encode 868 ORFs, ranging in size from 54 to 2,914 amino acids. Furthermore, this genome was predicted to encode 40 new genes (ORFans) without similarity with other sequences. These findings show that the widen chart of protists apply lead to discover new giant viruses.
403

Solid State Chemistry Of Transition Metal Oxides With Fascinating Properties

Mahesh, R 02 1900 (has links) (PDF)
No description available.
404

A Digital Spectral Correlator For GMRT

Tatke, V M 01 1900 (has links) (PDF)
No description available.
405

Première mesure des résonances géantes isoscalaires dans un noyau exotique riche en neutrons : le 68Ni avec la cible active Maya / First measurement of the isoscalar giant resonances in a neutron rich exotic nucleus (68Ni) using Maya active target

Vandebrouck, Marine 13 September 2013 (has links)
L’étude des résonances géantes monopolaires isoscalaires (ISGMR) et des résonances géantes quadrupolaires isoscalaires (ISGQR) dans les noyaux stables, a permis d’obtenir ces dernières décennies des informations fondamentales sur la structure et la matière nucléaire. En particulier, le centroïde de la ISGMR peut être relié au module d’incompressibilité de la matière nucléaire infinie. Des données dans les noyaux exotiques nous aideraient à contraindre ce module d’incompressibilité. Dans les noyaux instables, une seule mesure a, à l’heure actuelle, été réalisée (56Ni). Afin d’étudier l’évolution de la ISGMR et de la ISGQR le long d’une chaîne isotopique, des mesures dans un noyau exotique riche en neutrons sont donc nécessaires.L’expérience étudiée dans cette thèse a été réalisée au Grand Accélérateur National d’Ions Lourds (GANIL) à Caen en septembre 2010. Un faisceau de 68Ni à 50 AMeV et d’une intensité de 10^4 pps a été produit et purifié sur la ligne LISE. Les réactions de diffusion inélastique de particules alpha (alpha, alpha’) et de deutons (d,d’) sur 68Ni en cinématique inverse ont été étudiées avec la cible active Maya. Il s’agit de la première mesure de la ISGMR et de la ISGQR dans un noyau instable riche en neutrons.Pour chaque expérience, le spectre en énergie d’excitation a été reconstruit et les distributions angulaires étudiées par deux méthodes indépendantes. Les sections efficaces expérimentales ont été comparées à celles issues de calculs DWBA utilisant des densités de transition RPA. L’analyse en (alpha, alpha’) a permis l’observation d’une ISGMR fragmentée avec un épaulement à 21.1+/-0.6 MeV, d’une ISGQR concentrée à 16.9+/-0.8 MeV qui épuise 61+/-17% de la règle de somme pondérée en énergie (EWSR). De plus, un mode « soft GMR », prédit mais jamais observé, a été identifié à 13.4+/-0.5 MeV. Tous ces résultats sont confirmés par l’analyse en (d,d’), à l’exception de l’observation de la ISGQR pour laquelle les conditions de fonctionnement n’étaient pas favorables. / The study of the Isoscalar Giant Monopole Resonance (ISGMR) and the Isoscalar Giant Quadrupole Resonance (ISGQR) in stable nuclei provided relevant information on both nuclear matter and nuclear structure in past decades. For instance the centroid of the ISGMR can be linked to the incompressibility modulus of the infinite nuclear matter. Values for exotic nuclei would help in constraining it. In unstable nuclei, only one measurement has been performed so far (56Ni) and in order to study the evolution of the ISGMR and the ISGQR along an isotopic chain, measurements in neutron-rich Ni are called for.To reach this goal, a dedicated experiment was performed at GANIL in Septembre 2010. A 68Ni beam at 50 AMeV and with an intensity of 10^4 pps has been produced on LISE beamline. The inelastic scattering of alpha (alpha, alpha’) and deuteron particles (d,d’) on 68Ni in inverse kinematics has been studied with the active target Maya. It is the first attempt to measure the ISGMR and ISGQR in an unstable neutron-rich nucleus. For each experiment, the excitation energy spectrum has been reconstructed and the angular distributions have been studied with two independant methods. Experimental differential cross sections have been compared to DWBA calculations using RPA transition density in order to deduce the properties of the states observed. Concerning the analysis in (alpha, alpha’), the ISGMR is fragmented with a shoulder at 21.1+/-0.6 MeV, the ISGQR is concentred at 16.9+/-0.8 MeV and exhausted 61+/-17% of the Energy Weighted Sum Rule (EWSR). Moreover, a « soft GMR », predicted but never observed, is identified at 13.4+/-0.5 MeV. All these results are confirmed with the experiment in (d,d’), with the exception of the ISGQR due to unadapted experimental conditions.
406

Giant Molecules Based on Functionalized Fullerenes: Precise Synthesis and Diverse Assembly Behaviors

Lin, Zhiwei 04 October 2016 (has links)
No description available.
407

Panda a panda / Panda & panda

Kocmanová, Michaela January 2020 (has links)
This diploma thesis presents a project documentation for construction of a zoo pavilion with a restaurant. The structure has to be designed in compliance with regulations for buildings with almost zero energy consumption. Its construction site is located within the existing compound of Prague’s zoo on plot no. 1491/1. The pavilion is proposed to house giant pandas. The building has three floors- one underground and two above. It is covered by a flat green roof. In terms of circulation, the structure is composed from two parts. The first one is formed by premises for the pandas, including necessary facilities for their wellbeing and their breeding; and the second part is visitors’ part, including restaurant, gift shop and amenities. The building is enclosed by two exterior expositions for pandas which are connected with the interior exposition premises by two ramps- tunnels. There is a roof terrace adjacent to the restaurant for visitors to enjoy the view of pandas in their exterior grounds. The vertical structure of the pavilion for giant pandas is a combination of load bearing brick walls and cast-in-place concrete walls- the underground floor and the ground floor is formed by the cast-in-place concrete walls and the upper floor is formed by the brick walls made out of autoclaved aerated concrete blocks. The horizontal structures are formed by prestressed concreted floor panels or in the case of the upper floor by cast-in-place reinforced concrete slabs.
408

[en] METHODS TO HOMOGENIZE THE IMPEDANCE PHASE CHARACTERISTICS OF GMI SENSORS / [pt] MÉTODOS PARA HOMOGENEIZAÇÃO DAS CARACTERÍSTICAS DE FASE DA IMPEDÂNCIA DE SENSORES GMI

19 November 2021 (has links)
[pt] A utilização de magnetômetros possibilita o diagnóstico não invasivo e inócuo das variáveis fisiológicas já mensuradas pelos procedimentos padrão e oferece informações complementares sobre outras variáveis fisiológicas. Fontes biológicas geram densidades de fluxo magnético com ordem de grandeza entre 1 nT e 1 fT, com frequências até 1 kHz. Essas grandezas são ínfimas quando comparadas com a gerada pelo planeta, que é da ordem de 20 uT e está onipresente na atmosfera. Portanto, para mensurar campos biomagnéticos, é necessário atenuar essa interferência eletromagnética, sendo empregadas câmaras magneticamente blindadas e/ou transdutores em configuração gradiométrica. As câmaras blindadas apresentam alto desempenho de filtragem, mas têm elevado custo e pouca praticidade. Uma configuração gradiométrica utiliza uma leitura diferencial de dois ou mais elementos sensores idênticos, melhorando significativamente a relação sinal/ruído com baixo custo de implementação. Seu funcionamento se baseia na premissa de que os sensores têm comportamento idêntico. No entanto, foi observado que as fitas GMI, mesmo apresentando a mesma composição química e mesmas dimensões físicas, não apresentam as mesmas variações de fase para uma mesma variação do campo magnético. Ou seja, foi constatado um comportamento heterogêneo das amostras, o que impossibilitaria o desenvolvimento de um gradiômetro baseado nesses sensores. Diante deste impedimento, foi considerado o desenvolvimento de um circuito capaz de homogeneizar as variações de impedância entre duas amostras, quando associado a uma delas. Assim, a presente dissertação apresenta três métodos para a homogeneização das características de fase de amostras GMI e identifica o mais adequado para aplicações biomédicas. / [en] The use of magnetometers enables noninvasive and innocuous physiological variables already measured by standard procedures, and in certain cases, such as the Magnetocardiography offers additional information on other physiological variables diagnosis. Typically, the human heart generates a magnetic field with flux magnitude and frequency of 1 nT to 1 kHz. These quantities are minuscule compared with Earth s magnetic field, which is of the order of 20 uT and is omnipresent in the atmosphere. Therefore, to measure biomagnetic fields, it is necessary to reduce this and other electromagnetic interference, magnetically shielded cameras and transducers in gradiometric configuration are commonly used. Shielded cameras feature high performance filter, but have high cost and little practicality. A gradiometric configuration uses a differential reading of two or more identical sensor elements, significantly improving the signal/noise ratio with low implementation cost. However, its operation based on the premise that the sensors have identical behavior. Unfortunately, it was found that GMI ribbons, despite having the same chemical composition and same physical dimensions does not present the same phase variations for the same variation in magnetic field. That is, a heterogeneous behavior of the samples, which would prevent the development of a gradiometer based on these sensors. Given this impairment, it was considered developing a circuit capable of homogenizing the variations in impedance between two samples when associated with them. Thus, this paper presents three distinct characteristics of the homogenization phase samples GMI methods and identifies the most suitable for biomedical applications through a comparative analysis of the performance of the methods.
409

Měření vlastností tenkých vrstev metodami zobrazovací reflektometrie a Kerrova jevu / Measurement of thin films properties by imaging spectroscopy and magnetooptical Kerr effect

Plšek, Radek January 2008 (has links)
This thesis is divided into three main sections that deal with optical and magnetic thin films properties and their measurements techniques. Principles of the spectroscopic reflectometry and measurements of optical properties are described in the first part. Results of imaging reflectometry are most important. This technique is based on in situ monitoring of optical properties of SiO2 thin films during etching over the area cca 10 × 13 mm2. In next section magnetic properties of thin films and new apparatus built on the Institute of Physical Engineering of BUT are shown. Magnetic properties were observed by longitudinal magneto-optical Kerr effect. The construction of the device is based on a light beam with rectilinear polarization reflected from magnetic material with turned polarization. For investigation of local magnetic properties of microstructures a microscope objective focusing laser beam on the sample is used. The last part of the thesis is aimed on improving of a spin valve structure Co/Cu/NiFe. This work was done within the frame of the Erasmus project in Laboratoire Louis Néel in Grenoble. The goal was to achieve the value of GMR (Giant Magnetoresistance) as high as possible by changing of deposition parameters. This value describes the rate of resistances in different mutual directions of magnetization in trilayers.
410

KVANTIFIKACE A ZVYŠOVÁNÍ PŘESNOSTI MĚŘENÍ PRŮHYBU MOSTŮ / Quantification and improvement in bridge precision measurement deflection

Hvozdenský, Petr January 2008 (has links)
This thesis deal with improvement in bridge precision measurment deflection for Mostní a silniční Ltd. Its goal is through analysis of process of measurment and factor location, which have fundamental influence on measurment precision. First, theoretic part, represents the company, formulates problems and goals of thesis, history of bridges, world disasters, sort of bridges measurments, bridges evaluation and questions of giant transportation. In second, practical part, problems with measurment and its evaluation are described. Results are evaluated and corrective measures and recommendation are proposed in the final part.

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