The most compelling evidence of the complex interaction between the geomagnetic field of the Earth and the magnetic field of the Sun is found in the polar ionosphere. Large scale F-region plasma density perturbations result from the coupling between the two fields. Plasma density enhancements known as ionization patches, and depletions can have lifetimes of several hours in the F region and are almost always present everywhere throughout the nighttime polar ionosphere. The perturbations can seed ionospheric irregularities that severely hamper communication and navigational networks, even during times of subdued geomagnetic activity. Up until recently, it has been difficult to study the perturbations due to the remoteness of their location. In the past decade an array of optical and radio instruments have been deployed to the Canadian sector of the Arctic, enabling a more thorough sampling of the polar ionosphere and the large scale perturbations therein. In this work, common volume measurements from the Rankin Inlet Super Dual Auroral Radar Network (SuperDARN), Resolute Bay Incoherent Scatter Radar - North (RISR-N) and Optical Mesosphere and Thermosphere Imagers (OMTI) system at Resolute Bay are employed to investigate the generation mechanisms, transport properties, and optical and radio signatures of the large scale perturbations. A model connecting the optical signatures of patches to their velocity profile through the ionosphere is introduced and applied to OMTI data. In addition, an algorithm is developed to detect the presence of patches using RISR-N. Using the algorithm, a survey of patches sampled over several days is conducted, providing a comprehensive account of the variable polar ionosphere in terms of its plasma state parameters. Furthermore, the algorithm is used to diagnose patches as a primary source of coherent backscatter for the Rankin Inlet SuperDARN radar. Lastly, the generation of a deep plasma density depletion is analyzed using the three aforementioned instruments. Using a model, it is shown that such perturbations can be forged by intense frictional heating events in the polar ionosphere on a time scale of 15 minutes, and can subsequently be transported through the region.

Pc3-4 waves are recorded as geomagnetic pulsations with periods of 6-100s. They are generated at the bowshock and propagate to mid and auroral latitudes as Alfvén waves along closed magnetic field lines. At these latitudes Pc3-4 waves have been studied on the ground using magnetometers and in the ionosphere using HF radar. These waves have also been observed using magnetometers at polar latitudes even though there is no known propagation mechanism to the “open” field lines of the polar cap regions. In this work we used PolarDARN stations at Rankin Inlet and Inuvik to attempt the first study of Pc3-4 waves in the polar cap regions using radar. In ground scatter data, Doppler velocity oscillations with frequencies in the Pc3-4 range were found to be a common daytime occurrence. The oscillations are spatially coherent and in phase along the beam’s line of sight, matching lower latitude observations. However, upon further study it became apparent that the characteristics of the oscillations are different from those known for Pc3-4 waves. The observed oscillations have a diurnal trend that shows peaks in activity at 7:00 and 14:00MLT, where Pc3-4 oscillations have a diurnal peak at 10:30-11:00 MLT. In addition, poor coherence was observed between oscillations in radar and ground magnetic field variations at the nearby Taloyoak magnetometer. Further confounding the problem, we found that although the oscillations were coherent along the line-of-sight of the radar, poor coherence is observed when comparing oscillations in different beams separated by similar spatial scales. This finding counters both the spatial coherence observed along the beam’s line of sight and the spatial coherence of Pc3-4 waves at auroral latitudes. We conclude that it is unlikely that the observed oscillations are the result of Pc3-4 ULF waves. We instead propose that the observed Doppler velocity oscillations are caused by a change in the ionization along the ray’s path due to auroral particle precipitation.

Aurora occurs in various shapes, one of which is the hitherto unreported phenomenon of auroral fragments. For three periods of occurrence of these fragments their properties were studied in detail during this master’s thesis, using mainly ground-based instrumentation located near Longyearbyen on Svalbard, Norway. A base dataset was constructed from 103 all-sky camera images, manually marking 305 fragments for further analysis. This thesis reports and describes the fragment observations during the observed events, including the auroral and geomagnetic context. Fragments generally seem to fall into two categories, the first being singular, apparently randomly distributed fragments, and the second being periodic fragments that occur in groups with a regular spacing close to auroral arcs. A typical fragment has a small horizontal size below 20 km, a short lifetime of less than a minute and shows no field-aligned extent in the emission. The fragments appear mainly west of zenith (73%) during the three observation nights, whereas their north-south distribution is symmetric around the zenith. Almost all of them exhibit westward drift, the estimated speed for one of the fragments passing the field of view of ASK is ∼1 km/s. A spectral signature can be seen in the green auroral wavelength of O at 557.7 nm and red emission line of N2 at 673.0 nm, but no emission enhancement was observed in the blue wavelengths. One fragment passing the EISCAT Svalbard radar’s field of view shows a local ion temperature increase in a small altitude range of ∼15 km, whereas there is no visible increase in electron density. This could be explained by fragment generation due to locally strong horizontal electric fields. A potential mechanism for this might be electric fields of atmospheric waves superposing with the converging electric fields of auroral arcs created by particle precipitation and the corresponding field-aligned currents. The resulting field would be perpendicular to the magnetic field and the auroral arcs, leading to wave-like density variations of excited plasma close to the arcs. Further study is required to verify this hypothesis and improve the understanding of fragment properties determined from the limited dataset used for this thesis.

Joaquín Salvador Lavado Tejón, el famoso humorista gráfico conocido mundialmente como Quino, en una de sus tiras del 29 de julio de 2002 grafica una situación singular. A partir de cuatro viñetas ilustra la condición histórica de servidumbre que ha subsumido a la mujer desde la época más tradicional hasta la contemporánea. En la última viñeta, Mafalda concluye con la siguiente reflexión: ―Claro, lo malo es que la mujer en vez de jugar un papel, ha jugado un trapo en la historia de la humanidad‖ (Quino 2002). Emprendí el análisis de La sangre de la aurora por dos razones que están íntimamente ligadas a esta última sentencia de Quino: el papel de la mujer a lo largo de los diferentes procesos históricos y la función de ―trapo‖ que el sistema patriarcal le ha impuesto. / Tesis

Aurora A and B are the major kinases that control key events in mitosis, such as centrosome function, spindle assembly, chromosome segregation and cytokinesis, through phosphorylation of multiple proteins. These kinases share identical consensus target motifs, so the substrate specificity is determined by distinctive sub-cellular localization of the Auroras. Many proteins have been identified as targets of either Aurora A, or Aurora B, or both kinases by mass spectrometry studies. However, only a few of the identified phosphorylation sites in these targets have a characterized function in vivo. Therefore, the molecular mechanisms underlying the regulation of certain mitotic events by Aurora kinases remain unclear. The objective of my work was to develop a tool for identifying new substrates of both Aurora kinases. More specifically, I aimed to identify the molecular targets of Aurora A at the kinetochores, and determine how Aurora A contributes to the error correction near spindle poles. I first demonstrated that the outer kinetochore protein HEC1/Ndc80, phosphorylated by Aurora B at kinetochores, can also be phosphorylated by Aurora A close to the centrosomes (Chapter 2). My finding showed that Aurora kinases can share substrates in the cells and revealed the mechanism by which Aurora A contributes to the error-correction near spindle poles. To identify and characterise novel substrates of Aurora kinases, I developed a bioinformatic approach in collaboration with the Centre Bioinformatician, Alastair Kerr. This bioinformatic method uses the Auroras’ shared consensus motifs combined with several parameters that control the substrate specificity of Aurora kinases. I tested the phosphorylation of the chosen candidates in vitro using radiolabelled kinase assays. In my study, five proteins were validated - SPICE1, TTLL4, AHCTF1, CLASP2 and an uncharacterized protein KIAA1468 - as in vitro substrates of Aurora A and Aurora B kinases (Chapter 3). I then focussed on the Aurora kinases-dependent regulation of spindle and centriole-associated protein, SPICE1, in cells (Chapter 4). Using either site-directed mutagenesis of SPICE1 or inhibition of Aurora kinases with small molecule inhibitors, I found that the predicted phosphorylation of the SPICE1 C terminus had the function in cells of directing the SPICE1 localization on the spindle MTs. My results demonstrate the high accuracy of this genome-wide bioinformatics approach. By complementing mass spectrometry studies, here lies a potential for the identification of other unknown substrates, which is important for the general understanding of how Aurora kinases regulate the mitotic apparatus.

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No. of bitstreams: 2 license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Dissertacao_AbaixamentoMediasPretonicas.pdf: 2470175 bytes, checksum: c481c35c6ea14fc934823c010004e881 (MD5) Previous issue date: 2013 / A presente pesquisa teve como objeto de estudo a investigação do abaixamento das médias pretônicas na variedade do português falado em Aurora do Pará (PA). Pautou-se nos pressupostos da sociolinguística quantitativa de Labov (1972), suporte necessário para investigar e sistematizar a variação de uma comunidade linguística. Além destes, foram utilizados alguns procedimentos metodológicos adotados por Bortoni-Ricardo (1985) para as análises de redes sociais, importantes para o estudo de dialetos em comunidades de migração, como é o caso de Aurora do Pará, localizada na Mesorregião do Nordeste Paraense e que apresenta como particularidade o fato de ter recebido intenso fluxo migratório nas décadas de 60,70 e 80 do século passado. O corpus foi formado a partir de gravações de entrevistas de 28 informantes, divididos em dois grupos: a) um grupo de ancoragem, com 19 informantes migrantes do Ceará (9 (nove) do sexo masculino e 10 (dez) do sexo feminino), distribuídos nas faixas etárias de 30 a 46 anos e de 50 anos acima; b) outro de controle, com 9 (nove) informantes (3 (três) do sexo masculino e 6 (seis) do sexo feminino), paraenses descendentes do grupo de ancoragem. Os dados do corpus submetidos às análises somaram 4.033 ocorrências das vogais-objeto, anterior </e/> (2.394) e posterior </o/> (1.639). Foram estabelecidas como variáveis extralinguísticas: sexo, grupo de amostra, tempo de residência, e localidade. Para variáveis linguísticas, foram consideradas: natureza da vogal tônica, vogal pre-pretônica quando for oral, vogal pré-pretônica quando for nasal, vogal contígua, distância relativa à sílaba tônica, atonicidade, natureza do sufixo, consoante do onset da sílaba da vogal-alvo, consoante do onset da sílaba da vogal seguinte e peso silábico. Após as análises estatísticas computadas pelo software Goldvarb, os resultados mostraram que no dialeto de Aurora do Pará/PA predominam as variantes de não abaixamento – [.i,e] .71 e [o,u] .74 em detrimento das do abaixamento [E] .28 e [O] .26. Para o abaixamento, as variáveis favorecedoras foram: (i) natureza da vogal tônica, (ii) Vogal pré-pretônica, quando for oral, (iii) Vogal contígua, (iv) Distância relativamente à Sílaba Tônica, (v) Atonicidade, (vi) Natureza do sufixo, (vii) Consoante do onset da sílaba da vogal-alvo, (viii) Consoante do onset da sílaba seguinte, (ix) Peso silábico em relação à sílaba vogal alvo, (x) Sexo, (xi) Faixa etária, (xii) Tempo de residência. Os resultados revelaram perda da marca dialetal dos migrantes cearenses por conta do contato dialetal com outros dialetos e evidenciaram que o abaixamento vocálico no dialeto em questão é motivado, sobretudo pelo processo de harmonia vocálica. Tais resultados são reflexos da rede social dos informantes a qual tem baixa densidade e é uniplex, caracterizando-os como mais propensos a mudanças culturais e inovações linguísticas. / This research has as an object of study investigating the lowering of the average unstressed variety of Portuguese spoken in Aurora do Pará (PA). It was based on the assumptions of quantitative sociolinguistics Labov (1972), and support needed to investigate systematic variation of a language community. In addition, some methodological procedures adopted by Bortoni - Ricardo (1985) for analysis, important for the study of dialects in communities of migration, social networks were used as in the case of Aurora do Pará, located in the Northeast of Pará and Mesoregion its particularity that the fact of having received significant emigration in the decades of 60,70 and 80 of the last century. The corpus was formed from recordings of interviews of 28 informants were divided into two groups: a) a tether, with 19 migrant informants of Ceará ( nine (9) male and 10 (ten) female), distributed in the age groups 30-46 years and above 50 years; b) a control group, with nine (9) informants (three (3) males and six (6) female), group descended paraenses anchorage. The corpus data submitted to analysis totaled 4,033 occurrences of vowels object, previous </e/> (2394) and later </o/> (1639). Were established as extralinguistic variables: sex, sample group, residence time, and location. For linguistic variables were considered: the nature of the stressed vowel, pre- pretonica vowel when oral, pre-pretonica when nasal vowel, vowel contiguous distance on the stressed syllable, atonicidade, nature of the suffix, depending on the onset of the syllable vowel target, depending on the onset of the following vowel syllable and syllable weight. After statistical analyzes computed by Goldvarb software, the results showed that in the dialect of Aurora do Pará/PA predominant variants not lowering – [i,e].71 and [u,o] .74 at the expense of lowering - [ E] .28 and [O] .26 . For lowering favoring the variables were: ( i) the nature of the stressed vowel, (ii) pre- pretônica vowel, where oral, (iii ) vowel contiguous, (iv) distance from the syllable tonic, (v) atonicidade (vi) Nature of the suffix , (vii) depending on the onset of the syllable of the target vowel, (viii) depending on the onset of the following syllable, (ix) syllabic weight in relation to syllable vowel target, (x) sex, (xi) range age, (xii) residence time. The results revealed loss of dialectal brand of Ceará migrants because of the dialect contact with other dialects and showed that vowel lowering in the dialect in question is caused mainly by the vowel harmony process. These results are a reflection of the social network of informants which has low density and is uniplex, characterizing them as more likely to cultural changes and linguistic innovations.

The Earth's equatorial ionosphere most often shows the occurrence of large plasma density and velocity fluctuations with a broad range of scale sizes and amplitudes. These night time ionospheric irregularities in the F-region are commonly referred to as equatorial spread F (ESF) or plasma bubbles (EPBs). This dissertation focuses on analysis of ground-based optical and radar measurements to investigate the development and dynamics of ESF, which can significantly disrupt radio communication and GPS navigation systems. OI (630.0 nm) airglow image data were obtained by the Utah State University all-sky CCD camera, primarily during the equinox period, from three different longitudinal sectors under similar solar flux conditions: Christmas Island in the Central Pacific Ocean, Ascension Island in South Atlantic, and Brasilia and Cariri in Brazil. Well-defined magnetic field-aligned depletions were observed from each of these sites enabling detailed measurements of their morphology and dynamics. These data have also been used to investigate day-to-day and longitudinal variations in the evolution and distribution of the plasma bubbles, and their nocturnal zonal drift velocities. In particular, comparative optical measurements at different longitudinal sectors illustrated interesting findings. During the post midnight period, the data from Christmas Island consistently showed nearly constant eastward bubble velocity at a much higher value (~80 m/s) than expected, while data from Ascension Island exhibited a most unusual shear motion of the bubble structure, up to 55 m/s, on one occasion with westward drift at low latitude and eastward at higher latitudes, evident within the field of view of the camera. In addition, long-term radar observations during 1996-2006 from Jicamarca, Peru have been used to study the climatology of post-sunset ESF irregularities. Results showed that the spread F onset times did not change much with solar flux and that their onset heights increased linearly from solar minimum to solar maximum. On average, radar plume onset occurred earlier with increasing solar flux, and plume onset and peak altitudes increased with solar activity. The F-region upward drift velocities that precede spread F onset increased from solar minimum to solar maximum, and were approximately proportional to the maximum prereversal drift peak velocities.

Le complexe passager joue un rôle clé en mitose: contrôlant à la fois la ségrégation des chromosomes, la tension du fuseau, l'entrée en anaphase et la cytodirèse. Le complexe est composé de quatre protéines: INCENP, la kinase Aurora B, Survivine et Boréaline. Sachant que la protéine Survivine est phosphorylée par Aurora B et qu'elle a un role pivot au sein du complexe, nous avons étudié un mutant mimant sa phosphorylation: Survivine T117E. La phosphorylation de Survivine est nécessaire à la transition Métaphase/ Anaphase. Le mutant Survivine T117E est faiblement lié aux centromères en métaphase et agit comme un dominant négatif de la cytodirèse, empêchant la séparation des deux cellules filles. Lors de la recherche d'inhibiteurs des Aurora kinases, nous avons identifié une nouvelle classe de molécules qui inhibent la phosphorylation de l'histone H3 et le point de contrôle du fuseau. Ces molécules préviennent la prolifération des cellules tumorales. Ces composés sont des outils intéressants pour étudier la fonction du complexe passager et représentent un nouveau motif moléculaire pour le développement de drogues anticancéreuses. Survivine et Aurora B kinase dont l'expression est restreinte à la mitose sont deux cibles pour de nouvelles thérapies anti-mitotiques.

De nombreuses kinases participent au bon déroulement de chaque étape du cycle cellulaire. Chez les eucaryotes supérieurs, les kinases Aurora-A et Aurora-B, structuralement très proches, exercent des rôles fondamentaux durant la mitose. Aurora-A est une protéine localisée au niveau des centrosomes, impliquée dans le cycle de division du centrosome et la formation du fuseau mitotique. Aurora-B est une protéine passagère localisée sur les centromères et qui migre, en anaphase, sur le sillon de division et se concentre en cytocinèse sur le corps résiduel. Aurora-B est responsable de la phosphorylation massive, en mitose, du résidu Serine 10 de l'histone H3. Par un système de pseudo-génétique, j'ai ciblé, dans l'extrémité amino-terminale de Aurora-A, le domaine responsable de sa localisation centrosomique. Ces expériences ont montré que les domaines catalytiques de Aurora-A et Aurora-B possèdent tous deux un signal de localisation centromérique. Mais, à l'inverse de Aurora-B, le domaine catalytique de Aurora-A ne se transfert pas des centromères vers le sillon de division en anaphase. Ces travaux montrent également que Aurora-A est capable d'assurer une partie des fonctions mitotiques de Aurora-B. J'ai par ailleurs identifié et cloné la séquence de la protéine passagère TD-60 de Xenopus laevis. J'ai exprimé des domaines protéiques de la protéine xTD60, afin de générer un anticorps spécifique de TD-60 de xénope. Des expériences de co-sédimentation de complexes protéiques d'extraits mitotiques d'œufs de xénope et des expériences d'immunolocalisation cellulaire nous permettent d'envisager pour xTD-60 des fonctions plus larges que celles attribuées aux protéines passagères.

<p>The main purpose of this stydy was to evaluate the Aurora clinic (for women afraid of birth/delivery) in the south of Sweden. Questionnaires were sent to 197 women who had contact with the Aurora clinic during 2007 and 2008. The group of participants contained both pregnant women and women who have given birth. A total of 136 women replied. The results showed that both the average age and the level of education of the women were high. Nulli-paras and multi-paras had different reasons for fearing delivery. The study also showed that most women felt that the contact with an Aurora midwife helped them to feel secure and to be better prepared before delivery, that the midwife understood them and took them seriously and that the content of the meetings was satisfactory. Three out of four women, who initially wished for a caesarean section, subsequently accepted a normal delivery. This study supports previous research that shows the importance of the supportive conversation provided at the Aurora clinic for women with fear of delivery.</p>