Made available in DSpace on 2017-07-10T19:24:28Z (GMT). No. of bitstreams: 1 Gislaine Picollo de Lima.pdf: 510399 bytes, checksum: ea2c2de4321bd8f24facd8e31b533b09 (MD5) Previous issue date: 2008-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The cover crop adequacy to the implanted crop together with the adopted soil management system is important in order to obtain improvements on the system s yield and efficiency. Thus, this study aimed at examining the possible allelopathyc interference of black oat remains (Avena strigosa Schreb) and a consortium of black oat, forage turnip (Raphanus sativus L.) and vetch (Vicia sativa L.) on the speed emergency index (SEI) and emergency speed (ES) of seedlings, plants heights, weed incidence (large and narrow leaf), harvested seed quality and soybean yield Glycine max (L.) Merrill; considering different intervals among drying of cover crop using the Glyphosate 480 (3L ha-1) herbicide and the sowing of BRS 232 soybeans. The plots were marked on the field measuring 5 m x 2.5 m, adding 1 m borderline between them to the four treatment distributions for black oat cover, four treatments, the consortium and a control for each cover crop, completely randomized, with five replications. The cover crop was sowed in August, 2006; each row was 0.15m distant from each viii other. Later, the plots were dried on intervals of ten, twenty and thirty days before the soybean sowing, which was installed in November, 2006, with the 13 rows; each row was 0.45 m distant from each other and there were 14 seeds per linear meter. All the tests were submitted to an experimental design, with subdivided plots (split plot), completely randomized; the averages were also compared using Scott and Knott test at 5 % of significance. The study observed possible allelopathyc interference of cover crop on SEI, harvested seed quality, weed as well as the intervals of sowing and drying. / A adequação da cobertura vegetal à cultura agrícola, implantada em conjunto ao sistema de manejo de solo adotado, é importante para obtenção de melhorias na eficiência e produtividade do sistema. Dessa forma, o estudo em questão visou analisar a possível interferência alelopática dos restos vegetais de aveia preta (Avena strigosa Schreb) e consórcio de aveia preta, nabo forrageiro (Raphanus sativus L.) e ervilhaca comum (Vicia sativa L.) no índice de velocidade de emergência (IVE) e velocidade de emergência (VE) de plântulas, altura de planta, incidência de espécies invasoras (folha larga e folha estreita), qualidade da semente colhida e produtividade da cultura de soja Glycine max (L.) Merrill; considerando intervalos diferenciados entre a dessecação da cobertura vegetal com o herbicida Glyphosate 480 (3L ha-1) e a semeadura da soja BRS 232. No campo foi realizada a demarcação das parcelas em 5 m x 2,5 m, acrescido de 1 m de bordadura entre elas, para a distribuição de quatro tratamentos para a cobertura de aveia preta, quatro para o consórcio, e uma testemunha para cada cobertura, ao acaso, com cinco repetições. A cobertura vegetal foi semeada em agosto de 2006 com espaçamento de 0,15 m entre linhas; posteriormente, as parcelas foram dessecadas em intervalos variados de um, dez, vinte e trinta dias anteriores à semeadura da soja, a qual foi instalada em novembro de 2006, com espaçamento entre linhas de 0,45 m, treze linhas de semeadura e 14 sementes por metro linear. O delineamento experimental foi inteiramente casualizado, em esquema de parcela subdividida, comparando-se as médias pelo teste de Scott e Knott ao nível de 5 % de significância. O estudo observou possível interferência alelopática das coberturas vegetais no IVE, qualidade da semente colhida, espécies invasoras, assim como, nos intervalos entre dessecação e semeadura.

No region has felt the effects of global climate change more acutely than the cryosphere, which has changed at an unprecedented rate in the past two decades. The scientific consensus is that these changes are driven largely by increasing ocean heat content at high latitudes. In southeast Greenland, acceleration and retreat of the marine-terminating glaciers contributes significantly towards global sea level rise. Circulation in the fjords which accommodate these glaciers is thought to be driven both by freshwater input and by barrier wind-driven shelf exchange. Due to a scarcity of data, particularly from winter, the balance between these two mechanisms is not fully understood. In Svalbard, increasing water temperature has decimated sea ice cover in many of the fjords, and had substantial implications for the local ecosystem. While there is a relatively comprehensive literature on shelf exchange mechanisms in Svalbard fjords, questions remain over how the internal circulation interacts with exchange mechanisms. The region shares a similar underwater topography and oceanographic setting with southeast Greenland, with marine-terminating glaciers in close proximity to warm Atlantic waters, and results from Svalbard can hence be used to inform studies of high-latitude fjord-shelf exchange in a broader context. A realistic numerical model was constructed with the aim of better understanding the interaction between Kangerdlugssuaq Fjord and the adjacent continental shelf, and quantifying heat exchange during winter. The model was initially run in an idealised configuration with winter climatological forcing fields, incorporating a parameterisation for melting at the terminus, and used to test the impact of barrier wind events. The Earth's rotation played a crucial role in the nature of the circulation and exchange in the fjord, with inflow on the right (looking up-fjord) and outflow on the left. While the heat delivered into the fjord-mouth was smaller than that observed in summer, the background internal circulation was found to efficiently distribute waters through the fjord without external forcing, and the heat delivered to the glacier terminus was comparable to summer values. Barrier winds were found to excite coastally-trapped internal waves which propagated into the fjord along the right-hand side. The process was capable of doubling the heat delivery. The process also enhanced the background circulation, likely via Stokes' Drift. The model was then adapted to simulate winter 2007-08 under historical forcing conditions. Time series of glacial melt rate, as well as the heat flux through fjord cross-sections, were constructed and compared to the variability in wind forcing. Long periods of moderate wind stress were found to induce greatly enhanced heat flux towards the ice sheet, while short, strong gusts were found to have little influence, suggesting that the timescale over which the shelf wind field varies is a key parameter in dictating wintertime heat delivery from the ocean to the Greenland Ice Sheet. An underwater glider was deployed to Isfjorden, a large fjord system in Svalbard, to measure the temperature, salinity and depth-averaged currents over the course of November 2014. Like in Kangerdlugssuaq, the circulation in Isfjorden was found to be heavily influenced by the Earth's rotation and by wind activity both locally and on the shelf. The combination of hydrography and high-resolution velocity data provided new insights, suggesting that the approach will be useful for studying high-latitude fjords in the future.

The Solar Twin Planet Search program is an unprecedented eort that aimed to procure extrasolar planets in more than 70 stars extremely similar to the Sun. In the course of this program, hundreds of high-quality optical spectra were obtained for these stars using the HARPS spectrograph, which is fed by the ESO La Silla 3.6 m telescope. Beyond the search for exoplanets, the data are invaluable to study the physical properties of Sun-like stars. Particularly in this dissertation, we are interested in verifying if the Sun possesses a regular rotation for its age among stars that are strictly similar to it, how the rotation of solar twins evolve with age and if the rotation of Sun-like stars is influenced by the presence of stellar mass companions. Previous conclusions on the regularity of the Suns rotation have been conflicting, and this is the first time such a large sample of solar twins with high quality spectroscopic data is used to clarify this puzzle. Our results suggest that the Sun is indeed a regular rotator for its age, which favors the use of the solar rotation to calibrate gyrochronology -- the estimation of stellar ages from their rotation. However, these results also imply a rotational evolution process that saturates after the solar age, constituting a departure from the widely used Skumanich relation and posing a challenge for gyrochronology. We securely identified 18 binary or multiple systems in the solar twin sample, of which only three display enhanced rotation for their ages. I estimated the orbital parameters of the binaries from their radial velocity variations, and the results show that their spectroscopic companions lie at orbital periods varying from a few to several years. I conclude that the presence of red or brown dwarf companions at moderate to long orbital periods do not influence the evolution of rotation in these systems, and therefore the main stars should evolve as single in this regard. The peculiarities in HIP 19911, HIP 67620 and HIP 103983 can be fully explained by spectral contamination from their companions. / O programa The Solar Twin Planet Search é um esforço sem precedentes na procura de planetas extra-solares em mais de 70 estrelas extremamente similares ao Sol. Ao longo desse programa, centenas de espectros ópticos de alta qualidade foram obtidos com o espectrógrafo HARPS, que está instalado no telescópio de 3,6 m do Observatório de La Silla. Além da busca de exoplanetas, estes dados são úteis para estudar as propriedades físicas de estrelas como o Sol. Estamos interessados em verificar se o Sol possui uma rotação regular para sua idade quando comparado com estrelas estritamente similares a ele, como que a rotação de gêmeas solares evolui com o tempo e se a rotação dessas estrelas é influenciada pela presença de companheiras estelares. Conclusões anteriores na regularidade da rotação solar são conflitantes, e esta é a primeira vez que uma amostra grande de gêmeas solares com dados espectroscópicos de alta qualidade é usada para esclarecer essa questão. Nossos resultados sugerem que o Sol de fato rota regularmente para sua idade, o que favorece o uso da rotação solar para calibrar a girocronologia -- a estimativa de idades estelares a partir de sua rotação. No entanto, tais resultados também implicam em um processo de evolução rotacional que satura depois da idade solar, constituindo um desvio da amplamente usada relação de Skumanich e apresentando um desafio para a girocronologia. Nós identificamos 18 sistemas binários na amostra de gêmeas solares, das quais apenas três mostram rotações elevadas para suas idades. Os parâmetros orbitais das binárias foram estimados a partir da variação de suas velocidades radiais, e os resultados mostram que suas companheiras espectroscópicas possuem períodos orbitais variando de alguns poucos até muitos anos. Concluimos que a presença de companheiras do tipo anãs vermelhas ou marrons em períodos orbitais moderados não influenciam a evolução rotacional desses sistemas. As peculiaridades de HIP 19911, HIP 67620 e HIP 103983 podem ser completamente explicadas por contaminação espectral de suas companheiras.

Made available in DSpace on 2017-05-12T14:46:57Z (GMT). No. of bitstreams: 1 Marcia Mauli.pdf: 2078988 bytes, checksum: f7acd59f9f9540c3713e7315d3a18a92 (MD5) Previous issue date: 2013-11-12 / This trial aimed at isolating and identifying secondary compounds of winter cover crops as black oats, turnip and hairy vetch in order to meet the growing need for healthy products that do not harm the environment. It also enlarges the management knowledge of such crops to demonstrate their advantages on weed control and stimulate the use of a correct no-tillage system, since there is some evidence of their allelopathic potential. Parameters that help on elucidating decomposition of plant residues and releasing allelochemicals to inhibit Bidens pilosa have been evaluated as inhibition percentage according to the amount of mass, which used the amounts of 10, 20, 30, 40 and 50 g, equivalent to 7.5, 15, 22.5, 30 and 37.5 t ha -1, and as well as the control treatment (no mass cover). It was also evaluated influence of field capacity on the wastes decomposition, with 50 and 70% of available water plus the control (100%). There was some releasing of allelochemicals by permanence of plant material on the soil in order to evaluate their respective periods of vegetable permanence: 0, 2, 4, 6 and 8 weeks and the application of soil solution where cover crops were cultivated, which were tested in a concentrated way and at the following dilutions 100, 200, 300 and 400 mL L- 1, as well as the control. In all tests, emergence (inhibition emergence percentage, emergence speed index - ESI and emergence speed - ES) during 10 days and initial development (fresh and dry weight of shoot and root) during 30 days were evaluated. Five seeds or seedlings have been used in pot and 20 of them in gerbox, with three replications. The secondary compounds were obtained by exhaustive extraction during seven days, isolated by column chromatography by wet (CCW) and identified by nuclear magnetic resonance (NMR). The main chemical groups in plants were also identified through techniques such as fingerprint and phytochemical screen. The experimental design was completely randomized. Quantitative data were submitted to variance analysis to check significance and were submitted to regression analysis. The qualitative data were submitted to average comparison by Tukey test at 5 % probability. Generally, the greater residue amount on soil, the greater is B. pilosa inhibition. The best regarding water content in soil is that the result must range between 70 and 50%, which is when the greatest inhibitions occurred. During the evaluation of decomposition periods, there was greater interference on sterilized soil and the residue management than the period itself. Thus, the most significant results were found in no sterilized soil and residue incorporation. The soil solution showed considerable changes in B. pilosa emergence only during the last sampling collections, especially in oilseed radish and hairy vetch. The results, in this case, were more significant when germitest paper was used than sand as substrate. In relation to the compounds, it was detected the presence of tannins, steroids and triterpenoids, derived from coumarin, spumidic saponin and alkaloids. So, based on the observed positive changes, it is recommended to use these cover crops in crop rotation with soybeans to reduce B. pilosa weed / Este trabalho teve por objetivo isolar e identificar os compostos secundários das espécies de cobertura de inverno tais como aveia preta, nabo forrageiro e ervilhaca peluda a fim de suprir a crescente necessidade de busca por produtos saudáveis e que não agridam o meio ambiente. Além de ampliar os conhecimentos sobre o manejo dessas plantas, para demonstrar suas vantagens no controle de plantas invasoras e incentivar o uso do sistema plantio direto de forma adequada, já que as mesmas possuem evidências de potencial alelopático. Parâmetros que auxiliassem na elucidação da decomposição dos resíduos vegetais e liberação de aleloquímicos na inibição de picão preto foram avaliados, como a porcentagem de inibição em função da quantidade de massa, usando as quantidades de 10, 20, 30, 40 e 50 g, equivalentes a 7,5; 15; 22,5; 30 e 37,5 t ha-1, além da testemunha (sem cobertura). Também foi avaliada a influência da capacidade de campo na decomposição dos resíduos, com 70 e 50% de água disponível, mais a testemunha (100%). Houve a liberação de aleloquímicos pela permanência do material vegetal sobre o solo, em que foram avaliados os respectivos períodos de permanência vegetal: 0; 2; 4; 6 e 8 semanas e aplicação de solução do solo onde foram cultivadas as espécies de cobertura, as quais foram testadas de forma concentrada e nas diluições 100; 200; 300 e 400 mL L-1, mais a testemunha. Em todos os testes foram avaliados: emergência (porcentagem de inibição de emergência, índice de velocidade de emergência IVE e velocidade de emergência, VE) durante 10 dias e desenvolvimento inicial (massa fresca e seca de parte aérea e da raiz) durante 30 dias. Cinco sementes ou plântulas em vaso e 20 delas em gerbox foram utilizadas, com três repetições. Os compostos secundários foram extraídos por extração exaustiva durante sete dias; isolados por coluna cromatográfica por via úmida (CCVU) e identificados por ressonância magnética nuclear (RMN). Os principais grupos químicos presentes nas plantas também foram identificados por meio das técnicas fingerprint e screen fitoquímico. O delineamento experimental foi inteiramente casualizado (DIC). Os dados quantitativos foram submetidos à análise de variância para verificação de significância e submetidos à análise de regressão. Os qualitativos foram submetidos à comparação de médias pelo teste de Tukey a 5% de probabilidade. De modo geral, quanto maior a quantidade de resíduo sobre o solo, maior a inibição de picão preto. O ideal é que, no que se refere à quantidade de água no solo, o resultado fique entre 70 e 50%, quando ocorreram as maiores inibições. Na avaliação dos períodos de decomposição, houve maior interferência do solo esterilizado e do manejo do resíduo do que do próprio tempo. Todavia, os resultados mais expressivos foram encontrados em solo não esterilizado e com incorporação do resíduo. A solução do solo apresentou alterações consideráveis na emergência de picão preto apenas nas últimas coletas, principalmente em nabo forrageiro e ervilhaca peluda. Os resultados, neste caso, foram mais expressivos quando se utilizou papel germiteste do que areia como substrato. Com relação aos compostos presentes nas plantas, detectou-se a presença de taninos, esteroides e triterpenóides, derivados de cumarina, saponina espumídica e alcaloides. Em vista dos resultados observados, recomenda-se o uso dessas plantas de cobertura na rotação de culturas com a soja, visando à diminuição da planta invasora picão preto

Made available in DSpace on 2017-05-12T14:47:46Z (GMT). No. of bitstreams: 1 Gislaine Picollo de Lima.pdf: 510399 bytes, checksum: ea2c2de4321bd8f24facd8e31b533b09 (MD5) Previous issue date: 2008-02-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The cover crop adequacy to the implanted crop together with the adopted soil management system is important in order to obtain improvements on the system s yield and efficiency. Thus, this study aimed at examining the possible allelopathyc interference of black oat remains (Avena strigosa Schreb) and a consortium of black oat, forage turnip (Raphanus sativus L.) and vetch (Vicia sativa L.) on the speed emergency index (SEI) and emergency speed (ES) of seedlings, plants heights, weed incidence (large and narrow leaf), harvested seed quality and soybean yield Glycine max (L.) Merrill; considering different intervals among drying of cover crop using the Glyphosate 480 (3L ha-1) herbicide and the sowing of BRS 232 soybeans. The plots were marked on the field measuring 5 m x 2.5 m, adding 1 m borderline between them to the four treatment distributions for black oat cover, four treatments, the consortium and a control for each cover crop, completely randomized, with five replications. The cover crop was sowed in August, 2006; each row was 0.15m distant from each viii other. Later, the plots were dried on intervals of ten, twenty and thirty days before the soybean sowing, which was installed in November, 2006, with the 13 rows; each row was 0.45 m distant from each other and there were 14 seeds per linear meter. All the tests were submitted to an experimental design, with subdivided plots (split plot), completely randomized; the averages were also compared using Scott and Knott test at 5 % of significance. The study observed possible allelopathyc interference of cover crop on SEI, harvested seed quality, weed as well as the intervals of sowing and drying. / A adequação da cobertura vegetal à cultura agrícola, implantada em conjunto ao sistema de manejo de solo adotado, é importante para obtenção de melhorias na eficiência e produtividade do sistema. Dessa forma, o estudo em questão visou analisar a possível interferência alelopática dos restos vegetais de aveia preta (Avena strigosa Schreb) e consórcio de aveia preta, nabo forrageiro (Raphanus sativus L.) e ervilhaca comum (Vicia sativa L.) no índice de velocidade de emergência (IVE) e velocidade de emergência (VE) de plântulas, altura de planta, incidência de espécies invasoras (folha larga e folha estreita), qualidade da semente colhida e produtividade da cultura de soja Glycine max (L.) Merrill; considerando intervalos diferenciados entre a dessecação da cobertura vegetal com o herbicida Glyphosate 480 (3L ha-1) e a semeadura da soja BRS 232. No campo foi realizada a demarcação das parcelas em 5 m x 2,5 m, acrescido de 1 m de bordadura entre elas, para a distribuição de quatro tratamentos para a cobertura de aveia preta, quatro para o consórcio, e uma testemunha para cada cobertura, ao acaso, com cinco repetições. A cobertura vegetal foi semeada em agosto de 2006 com espaçamento de 0,15 m entre linhas; posteriormente, as parcelas foram dessecadas em intervalos variados de um, dez, vinte e trinta dias anteriores à semeadura da soja, a qual foi instalada em novembro de 2006, com espaçamento entre linhas de 0,45 m, treze linhas de semeadura e 14 sementes por metro linear. O delineamento experimental foi inteiramente casualizado, em esquema de parcela subdividida, comparando-se as médias pelo teste de Scott e Knott ao nível de 5 % de significância. O estudo observou possível interferência alelopática das coberturas vegetais no IVE, qualidade da semente colhida, espécies invasoras, assim como, nos intervalos entre dessecação e semeadura.

A ideia deste trabalho é apresentar a conjetura de Boyland para o anel e mostrar algums resultados nessa direção. Tal conjectura diz que: Dado um homeomorfismo irrotacional do anel, que possui uma medida com número de rotação positivo, é verdade que, neste caso, existem pontos com número de rotação negativo? Para dar uma resposta parcial a esta pregunta, nesta dissertação (baseada no estudo do [7]) começamos considerando os homeomorfismos do anel que preservam orientação, as componentes de fronteira, com número de rotação positivos em ambas fronteiras, e que tem un levantamento transitivo (o motivo desta hipoteses vem de [3]), mostrando que neste caso 0 está no interior do conjunto de rotação. Este resultado vai permitir provar a conjetura para os homeomorfismos do anel irrotacionais, sem pontos fixos na fronteira e com um levantamento transitivo. Além disso vai permitir estudar a dinâmica de tais homeomorfismos. No final do trabalho, estendemos algums dos teoremas provados ao longo dos capítulos anteriores a um conjunto maior de homeomorfismos e estudamos o comportamento de tais homeomorfismos com base nestes resultados. / The idea of this work is to present Boyland´s Conjecture for the annulus and show some results in its direction. The conjecture is the following: Given a homeomorphism of the annulus, which has a measure with positive rotation number, is it true that, in this case, there are points with negative rotation number?. To give a partial answer to this question, in this dissertation (based on [7]) we begin considering the homeomorphisms of the annulus that preserve orientation and boundary components, with positive rotation numbers in the boundaries, with has a transitive lift (the reason for this hypothesis is in [3]), and we show that 0 is in the interior of the rotation set. This result will be of help to prove the Boyland´s Conjecture for rotationless homeomorphisms of the annulus, without fixed points in the boundaries and with a transitive lift. In addition, we will be able to study the dynamics of such homeomorphisms. In the end of this work, we extend some of the theorems proved in the previous chapters to a bigger set of homeomorphisms and we study the behavior of such homeomorphisms using these results.

Nous présentons une étude expérimentale de l'influence d'une rotation d'ensemble sur le déclin d'un écoulement turbulent dans une géométrie confinée. L'écoulement est généré en translatant rapidement une grille dans un récipient parallélépipédique, et nous mesurons les champs de vitesse dans un plan vertical (parallèle à l'axe de rotation) grâce à un dispositif de PIV embarqué. Nous montrons dans un premier temps qu'une partie significative de l'énergie est contenue dans un écoulement moyen reproductible, qui s'identifie à une superposition de modes d'inertie résonnants de la cuve. Le couplage possible entre cet écoulement et la turbulence suggère que la turbulence ainsi créée n'est pas en déclin libre. Nous montrons cependant qu'il est possible d'inhiber l'apparition de ces modes d'inertie en modifiant les caractéristiques géométriques de la grille. Cette nouvelle configuration permet alors de caractériser dans l'espace physique les transferts d'énergie pour une turbulence en déclin libre. L'énergie associée aux incréments de vitesse et la densité de flux d'énergie sont calculées à partir d'un grand nombre de réalisations indépendantes. Nous montrons que la rotation provoque une forte bidimensionalisation de la distribution d'énergie, et que celle-ci est contrôlée par une densité de flux d'énergie qui reste quasi-radiale, mais qui fait apparaître une dépendance angulaire marquée. Enfin, nous étudions également l'écoulement dans un cube, que nous soumettons à une libration longitudinale afin d'exciter les modes observés initialement avec le dispositif de turbulence de grille. En comparant les champs de vitesse expérimentaux aux prédictions numériques des modes inviscides, nous montrons que seul un certain nombre de modes, compatibles avec les symétries du forçage, peuvent être excités par libration. Nous caractérisons en particulier la résonance du mode de plus bas ordre compatible avec les symétries du forçage, et discutons du rôle de la viscosité. / We investigate the effect of a backgroung rotation on the decay of a turbulent flow in a confined geometry. Turbulence is generated by rapidly towing a grid in a parallelepipedic water tank. The velocity fields of a large number of independent decays are measured in a vertical plane parallel to the rotation axis using a corotating Particle Image Velocimetry system. We first show that a significant amount of the kinetic energy is stored in a reproducible flow composed of resonant inertial modes. The possible coupling between these modes and turbulence suggests that turbulence cannot be considered as freely decaying in this configuration. We demonstrate however that these inertial modes may be reduced by changing the geometrical features of the grid. Thanks to this new configuration, anisotropic energy transfers in freely decaying turbulence in a rotating frame can be characterized experimentally in the physical space. The anisotropic energy flux density is determined from large data sets of Particle Image Velocimetry measurements. We show that in the presence of a background rotation, the energy distribution reflects a trend towards a 2D flow. This anisotropy is proved to be essentially driven by a nearly radial, but orientation-dependent, energy flux density. We also analyze the flow in a cubic container submitted to a longitudinal libration in order to generate inertial modes that were originally observed when the "simple" grid was used. By comparing the measured flow fields to the expected inviscid inertial modes, we show that only a subset of inertial modes, matching the symmetries of the forcing, may be excited by the libration. We characterize in particular the resonance of the mode of lowest order compatible with the symmetries of the forcing, and discuss the role of the viscosity.

In this thesis, the development and methodology of a new, consolidated BYU/NIC Antarctic Iceberg Tracking Database is presented. The new database combines data from the original BYU daily iceberg tracking database derived from scatterometers, and the National Ice Center's weekly Antarctic iceberg tracking database derived from mostly optical and infrared sensors. Using this data, interpolation methods and statistical analyses of iceberg locations are discussed. The intent of this database is to consolidate iceberg location data in order to increase accessibility to users.Active microwave remote sensing instruments are used to track tabular icebergs and provide a daily estimate of their positions and sizes. A consolidated data set of these positions from several different instruments is valuable to ensure accurate positional data. The scatterometer iceberg positional record began with the Seasat-A Satellite Scatterometer (SASS) and is continued with the Quick Scatterometer (QuikSCAT) and Advanced Scatterometer (ASCAT) data sets.A reliable method of automatically estimating Antarctic iceberg contours and sizes from satellite data is desirable to help better understand patterns in iceberg formation and behavior. Starting from scatterometer images, this thesis develops a method of using the relatively constant backscatter values across the surface of an iceberg to derive a contour of its shape. Contours are then used to find an angle of rotation between images taken on successive days. This method produces size estimates that are within 10% of the area given by the National Ice Center (NIC). The size estimates and rotation angles are included in the new consolidated database.

The MiMeS (Magnetism in Massive Stars) project is a large-scale, high-resolution, sensitive spectropolarimetric investigation of the magnetic properties of O- and early B-type stars. Initiated in 2008 and completed in 2013, the project was supported by three Large Program allocations, as well as various programmes initiated by independent principal investigators, and archival resources. Ultimately, over 4800 circularly polarized spectra of 560 O and B stars were collected with the instruments ESPaDOnS (Echelle SpectroPolarimetric Device for the Observation of Stars) at the Canada–France–Hawaii Telescope, Narval at the Télescope Bernard Lyot and HARPSpol at the European Southern Observatory La Silla 3.6 m telescope, making MiMeS by far the largest systematic investigation of massive star magnetism ever undertaken. In this paper, the first in a series reporting the general results of the survey, we introduce the scientific motivation and goals, describe the sample of targets, review the instrumentation and observational techniques used, explain the exposure time calculation designed to provide sensitivity to surface dipole fields above approximately 100 G, discuss the polarimetric performance, stability and uncertainty of the instrumentation, and summarize the previous and forthcoming publications.

No description available.