Orientador: Luís Eduardo Evangelista de Araujo / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin / Made available in DSpace on 2018-08-18T17:59:31Z (GMT). No. of bitstreams: 1 Carvalho_SilvaniaAlvesde_D.pdf: 4970692 bytes, checksum: f260af26ecacc7e92b1246968850ff9b (MD5) Previous issue date: 2011 / Resumo: Nesta tese apresentamos o estudo teórico de grades de difração induzidas em meios atômicos na condição de transparência induzida eletromagneticamente (EIT). As grades atômicas que serão descritas baseiam-se na não-linearidade Kerr gigante exibida pelos átomos sob EIT. No primeiro estudo realizado, a grade atômica é gerada a partir da modulação da não-linearidade Kerr através de uma onda estacionária. Neste estudo, aplicamos a teoria de ondas acopladas, desenvolvida originalmente para grades acústicas e holográficas, para a grade atômica de modo a obter uma expressão analítica para a eficiência de difração em primeira ordem. Altas eficiências de difração de um feixe de prova ressonante são previstas para incidência próxima ao ângulo de Bragg. Em um segundo estudo, descrevemos uma grade atômica do tipo ¿blazed¿ criada através da inserção de uma máscara de intensidade em um dos feixes responsáveis pela não-linearidade Kerr do meio. Eficiências de difração em primeira ordem para o feixe de prova próximas a 100% foram obtidas. Por último, discutimos uma grade de difração induzida na condição de coerência máxima entre os estados fundamentais de um átomo. Esta grade difrata não somente o feixe de prova incidente, mas também um segundo feixe gerado por mistura de quatro ondas. Apesar desta última grade apresentar eficiência de difração muito menor do que as duas grades anteriores, esta grade pode operar em vários comprimentos de onda diferentes, embora envolva sempre um feixe ressonante com alguma transição atômica. Além da contribuição teórica, trabalhos experimentais relacionados à área de aprisionamento e resfriamento de átomos foram realizados. Inicialmente, um experimento de espectrocopia de fotoassociação próximo ao limite de dissociação em uma amostra de 85Rb é apresentado. Em seguida, uma fonte de laser em 423 nm, formada por um laser de Ti-Sa com dobramento intracavidade através de um cristal LBO, que foi construída e estabilizada é descrita / Abstract: In this thesis we present a theoretical study on induced diffraction gratings in atomic media under electromagnetically induced transparency condition. The atomic gratings which will be described are based on the giant Kerr nonlinearity displayed by the atoms under EIT. In the first study, the atomic grating is generated from the modulation of the Kerr nonlinearity through a stationary wave. In this study, we apply coupled wave theory, originally developed for acoustic and holographic gratings, for an atomic grating in such a way that an analytical expression for the first order diffraction is obtained. High diffraction efficiencies of the resonant probe beam are predicted for incidence near Bragg angle. In a second study, we describe a blazed-type atomic grating created through the insertion of an intensity mask in one of the beam responsible for the Kerr nonlinearity of the medium. First order diffraction for the probe beam near 100% efficiency was observed. Finally, we discuss a diffraction grating induced under maximum coherence condition between the ground states of an atom. This grating diffracts not only the probe beam, but also a second beam generated by four wave mixing. Although this last grating shows a diffraction efficiency much smaller than the previous one, this grating can operate in several wavelengths, although involving a beam resonant with an atomic transition. Besides the theoretical contribution, experimental works related to the cooling and trapping of atoms were implemented. Initially, an experiment of photoassociation spectroscopy near the dissociation limit in a sample of cold rubidium atoms is presented. Following, a homebuilt laser source at 423 nm formed by a Ti-Sapphire laser with intracavity frequency doubling through a LBO crystal that was stabilized is described / Doutorado / Física Atômica e Molecular / Doutora em Ciências

L’enjeu principal de cette thèse a été de démontrer la faisabilité de l’Imagerie par Résonance Magnétique à très bas champ (entre 1 mT et 10 mT). Pour ce faire, un nouveau type de capteur, appelé “capteur mixte”, a été utilisé. Ce détecteur est le résultat de l’association d’une magnétorésistance géante avec une boucle supraconductrice. Il génère un bruit en champ comparable aux détecteurs les plus utilisés dans cette gamme de fréquence (Bobine accordées, SQUIDs, Magnétomètres atomique optique). Le couplage entre l’échantillon observé et le capteur mixte a été grandement amélioré à travers l’utilisation d’un transformateur de flux. Cet intermédiaire a été conçu et optimisé pour maximiser la sensibilité en champ du “capteur mixte”. Cet ensemble a ensuite été introduit dans un IRM à très bas champ magnétique pour tester son efficacité in-situ. Parallèlement, différentes séquences d’IRM (GE, SE, FLASH, EPI,...) ont été développées spécifiquement pour le très bas champ. Elles ont été utilisées pour réaliser de l’imagerie tridimensionnelle in-vivo ainsi que des études relaxométriques sur divers produits. Enfin, un système d’IRM “tête entière” a été construit pour permettre l’acquisition d’images à très bas champ magnétique sur un large volume. / The aim of this thesis is to perform Magnetic Resonance Imaging at very low field (from 1 mT to 10 mT). A new kind of sensor called “mixed sensor” has been used to achieve a good detectivity at low frequencies. Combining a superconducting loop and a giant magnetoresistance, those detectors have a competitive equivalent field noise compared to existing devices (Tuned coils, SQUIDs and Atomic Magnetometers). They have been combined with flux transformers to increase the coupling between the sample and the sensor. A complete study has been performed to adapt it to mixed sensors and then maximize the gain. This set has been incorporated in an existing small MRI device to test its robustness in real conditions. In parallel, several MRI sequences (GE, SE, FLASH, EPI, ...) have been integrated and adapted to very low field requirements. They have been used to perform in-vivo three dimensional imaging and relaxometry studies on well known products to test their reliability. Finally, a larger setup adapted for full-head imaging has been designed and built to perform images on a larger working volume.

We present a case of farmer’s lung (FL) with the primary presenting feature of a large bulla in the lung. A 70-year-old nonsmoking woman with dyspnea on exercise was referred for surgical resection of a large bulla in the lung. The postoperative evaluation of the lung tissue revealed a follicular lymphocytic alveolitis and loosely formed granulomas suspicious for hypersensitivity pneumonitis (HP). The patient had worked in farming since her youth. Dyspnea on exercise was the only symptom, but it was related to the large bulla. No other radiologic features of HP were shown in a high-resolution CT of the lung. Specific IgG antibodies against typical antigens of FL were detected, bronchoalveolar lavage demonstrated no lymphocytic alveolitis but an inhalative challenge with own hay was positive. A diagnosis of chronic FL was made. Despite lung emphysema being a possible reaction in FL, giant bullae as primary and single manifestation of this disease have not been reported before.

No description available.

This thesis is based and developed on the ambiguous and open conception, iconic species, which reveals the relationship between human society and non-human species that goes be- yond its biological status. From the case of the giant panda, I attempt to deconstruct the shap- ing process of an iconic species from multiple perspectives, which includes how a specific cultural context, or a specific historical period contributes to the shaping process and how the government and the public diverge or even clash around the shaping process. Then, I introduce my fieldwork where I through observing both giant pandas and red pandas in the exhibition centres called panda bases to analyse the encountering an iconic species in reality and their different influences on public awareness of the wildlife conservation. I also attempt to explore the various representative forms of an iconic species such as the Tibetan antelope ranging from the mascot to the film and follow the changes of its symbolic meanings in different forms. In conclusion, the thesis is aimed to reflect the hybrid features of the iconic species and pro- vide in-depth interpretation of the endless interactions between the human beings and other species.

Les nématodes à galles (RKN) du genre Meloidogyne spp. sont des parasites obligatoires des plantes qui induisent la formation d’un site nourricier spécialisé au sein des racines. Mon projet de thèse a pour objectif d’identifier des gènes spécifiques de ces nématodes qui sont impliqués dans le parasitisme en se focalisant sur des protéines sécrétées ou effecteurs. La technologie de séquençage Illumina a été utilisée pour comparer les transcriptomes de M. incognita au cours de son cycle de vie. A partir de 307 gènes surexprimés dans -au moins- un stade du cycle de vie, nous avons sélectionné 14 candidats d’effecteurs. Des expériences de RT-qPCR, d’hybridation in situ et d’ARN interférence ont permis de confirmer le profil d’expression, de localiser l’expression des effecteurs et d’étudier leur rôle dans la pathogénicité. Ce travail a permis de démontrer le rôle important d’une petite protéine, MiSCR1, dans les stades précoces du parasitisme. Parallèlement, nous avons réalisé l’assemblage de novo du transcriptome de M. enterolobii, qui représente une nouvelle menace pour l’agriculture mondiale du fait de sa capacité à se reproduire sur la majorité des plantes résistantes aux autres RKN. Les premières comparaisons avec d'autres RKN nous ont permis d'identifier, non seulement des effecteurs en commun, mais aussi ceux qui sont spécifiques à certaines espèces de RKN et qui pourraient expliquer des différences de gamme d'hôtes. En conclusion, les analyses de transcriptomes de RKN ont permis de caractériser des nouveaux effecteurs candidats impliqués dans la pathogénicité, et d’apporter de nouvelles connaissances pour le développement de méthodes de lutte contre ces bioagresseurs / Root-knot nematodes (RKN) are obligate endoparasites that maintain a biotrophic relationship with their hosts inducing specialized feeding cells. My PhD project aims to identify RKN genes specifically involved in plant parasitism with an emphasis on genes encoding new secreted proteins, named effectors. Using Illumina RNA-seq technologies, we compared transcriptomes of Meloidogyne incognita during its life cycle. From 307 genes over-expressed at -at least- one stage of the life cycle, we selected 14 effector candidates. RT-qPCR, in situ hybridisation and siRNA soaking experiments were carried out to confirm their expression profile, localize the spatial expression of these candidates in the nematode and to study their role in pathogenicity. The silencing of the dorsal gland specific-Minc18876 gene and its paralogues resulted in a significant, reproducible decrease in the number of egg masses, demonstrating a potentially important role for the small cysteine-rich effector, MiSCR1, it encodes in early stages of giant cell formation. In parallel, we perform a de novo assembly of M. enterolobii transcriptome. This RKN species represents a new threat for the agriculture worldwide because of its ability to reproduce on the majority of known RKN-resistant plants. First comparisons with others RKN allowed us to identify, not only the common set of effectors, but also those specific to some RKN species and possibly involved in host range differences. In conclusion, the transcriptome profiling of RKNs allowed the characterisation of new candidate effectors involved in the plant pathogenicity, and provided a better knowledge for the development of new methods to control these pests

At the time the Black and Red List of the Vascular Plants of the Krkonoše (Giant) Mountains was being compiled it was found that no information was available about the distribution of eyebright (Euphrasia) or other facts concerning this hemiparasite growing in the Krkonoše. The aim of this work was to fill the gap. This was to be done by creating a GIS layer with the current distribution of eyebright in the mountains, by analysing the soils taken in places of eyebright occurrence, in neighbouring places and those closely resembling them but without eyebright. The soils were taken each time from five places in the particular locality and were analysed as a mixed sample. In all, 107 mixed soil samples were taken, of which 53 in places where eyebright occurred and in 54 similar places where eyebright was absent. Eyebright grows in places with a higher pH and it performs better in lower available phosphorus concentration. Management test was used to test the earlier time of mowing meadows containing eyebright, when a larger number of flowering eyebright occurs among the plants in comparison with the number of flowering eyebright on surfaces mown at a later time.; Management testing was carried out from June to July 2011 in six localities, with five plots in each locality, in the Eastern and Western...

Context. Theoretical studies predict that the length scale of convection in stellar atmospheres isproportional to the pressure scale height, which implies that giant and supergiant stars should have convection granules of sizes comparable to their radii. Numerical simulations and the observation of anisotropies on stellar discs agree well with this prediction. Aims. To measure the characteristic sizes of convection structures of models simulated with the CO5BOLD code, to look at how they vary between models and to study their limitations due to numerical resolution. Methods. Fourier analyses are performed to frames from the models to achieve spatial spectral power distributions which are averaged over time. The position of the main peak and the averagevalue of the wavevector are taken as indicators of these sizes. The general shape of the intensity map of the disc in the frame is fitted and subtracted so that it does not contaminate the Fourier analysis. Results. A general relationship of the convection granule size being more or less ten times larger than the pressure length scale is found. The expected wavevector value of the time-averaged spectral power distributions is higher than the position of the main peak. Loose increasing trends with the characteristic sizes by the pressure scale height increasing against stellar mass, radius, luminosity,temperature and gravity are found, while a decreasing trends are found with the radius and modelresolution. Bad resolution subtracts signals on the slope at the side of the main peak towards larger wavevector values and in extreme cases it creates spurious signal towards the end of the spectrum due to artifacts appearing on the frames. Conclusions. The wavevector position of the absolute maximum in the time-averaged spectral power distribution is the best measure of the most prominent sizes in the stellar surfaces. The proportionality constant between granule size and pressure length scale is of the same order ofmagnitude as the one in the literature, however, models present sizes larger than the ones expected, likely because the of prominent features do not correspond to convection granules but to larger features hovering above them. Further studies on models with higher resolution will help in drawing more conclusive results. Appendix. The SIA pipeline takes a set of time-dependent pictures of stellar disks and uses a Fourier Analysis to measure the characteristic sizes of their features and other useful quantities, such as standard deviations or the spatial power distributions of features. The main core of the pipeline consists in identifying the stellar disc in the frames and subtracting their signal from the spatial power distributions through a general fit of the disc intensity. To analyze a time sequence, the SIA pipeline requires at least two commands from the user. The first commandorders the SIA pipeline to read the .sav IDL data structure file where the frame sequence is stored and to produce another .sav file with information on the spectral power distributions, the second command orders the reading of such file to produce two more .sav files, one containing time-averaged size measurements and their deviations while the other breaking down time-dependant information and other arrays used for the calculations. The SIA pipeline has been entirely written in Interactive Data Language (IDL). Most of the procedures used here are original from the SIA pipeline, but a small handfull like ima3_distancetransform.pro, power2d1d.pro, extremum.pro and smooth2d.pro from Bernd Freytag and peaks.pro and compile opt.pro amongst others are actually external. / <p>The report consists in two parts:</p><p>1.- The main project, where we apply our pipeline and get scientific results.</p><p>2.- The appendix, where a technical description of the pipeline is given.</p>

The present study deals with ecological impact of giant hogweed (Heracleum mantegazzianum) invasion in Slavkovský les area. Being one of the prominent invasive species with significant impact on human health it has been subjected to a wide research. In spite of that little is known about its impact on the invaded ecosystem. My research was therefore focused on analysis of the ecosystem impact, particulary 1) microclimatic measurements of temperature and soil moisture and their comparisons between invaded and noninvaded vegetation, 2) comparison of germination and survival of model plant species sowed into invaded and noninvaded plots and 3) study of the effect of H. mantegazzianum presence on model species seed production. Results have shown significant alteration of microclimate due to H. mantegazzianum invasion. Further research is needed to resolve what impact it may pose to species in invaded communities. The effect of Heracleum mantegazzianum presence on germination and survival of model species was not significant. Similarly, seed production of model plants was not significantly affected.

<p>  </p> <p>Giant ragweed (<em>Ambrosia trifida</em> L.) is an annual broadleaf plant capable of emergence throughout the cropping season, opportune colonization of disturbed soil, rapid biomass accumulation, and a propensity to evolve mutations that endow resistance to herbicides, all of which contribute to giant ragweed being one of the most challenging weeds to control in row-crop production. Many soybean growers rely on acetolactate synthase (ALS)-inhibiting herbicides such as cloransulam for control of giant ragweed prior to its emergence, though the spread of biotypes resistant to ALS inhibitors can render these herbicides largely ineffective. Mesotrione inhibits the 4-hydroxyphenylpyruvate dioxygenase (HPPD) enzyme, and applications of this herbicide have recently been approved for use in mesotrione-resistant soybean varieties. Field experiments demonstrated that preemergence applications of mesotrione resulted in greater control of giant ragweed populations segregating for ALS-inhibitor resistance than several other commonly used herbicide combinations. Where mesotrione was applied, giant ragweed biomass was reduced by an average of 84% relative to the nontreated, while treatments without mesotrione increased biomass by an average of 34% by suppressing competition from other weed species. Additionally, both soil- and agar-based bioassays demonstrated that combinations of mesotrione and metribuzin can be synergistic for control of giant ragweed. </p> <p>Cloransulam was shown to result in strong selection for giant ragweed individuals with ALS-inhibitor resistance, increasing the proportion of resistant plants that emerged at one field site from 15% to greater than 90% after a single preemergence application. This selection pressure was reduced when mesotrione was co-applied with cloransulam. However, no herbicide combination, including sequential applications of non-ALS-inhibiting herbicides, consistently resulted in a resistance frequency similar to the baseline if an ALS inhibitor was applied preemergence. Resistance to cloransulam and other ALS inhibitors is expressed in giant ragweed plants possessing at least one mutant (Trp574Leu) <em>ALS</em> allele. The distribution of this allele in one field violated the Hardy-Weinberg Equilibrium, despite the fact that <em>ALS</em> is a nuclear gene and the Trp574Leu mutation does not incur a fitness penalty. We suspected that the inheritance of this mutation may be linked with a gene or genes responsible for self-incompatibility (SI) in giant ragweed, and that linkage drag was disrupting pollination in resistant plants. This research provided evidence that giant ragweed does possess SI, as greater pollen retention, pollen tube growth, and seed set were observed in cross-pollinated plants compared with self-pollinated plants. Non-Mendelian inheritance of the Trp574Leu mutation was documented in crosses between plants from three different giant ragweed populations, indicating that the mutant <em>ALS</em> allele may be linked with an SI allele common to many plants because of a shared resistant ancestor.  In crosses between plants from one population, production of resistant F1 seeds was 33% greater on average compared with the expectation under Mendelian inheritance. </p> <p>Collectively, this research demonstrated that mesotrione may become a highly effective tool for control of giant ragweed in soybean. Applications of mesotrione can also reduce the selection for an increased frequency of ALS inhibitor-resistant biotypes induced by cloransulam, though a more robust weed management strategy may be necessary to maintain the long-term viability of ALS inhibitors.  The need for sound weed management practices is underscored by the impact of the linkage of SI and <em>ALS</em> genes, which may be encouraging a more rapid spread of herbicide-resistance than was previously anticipated.</p>