A deficiência de hormônio de crescimento (DGH) é a deficiência mais comum entre os hormônios pituitários. A terapia utilizada atualmente consiste de injeções diárias de hormônio de crescimento humano recombinante (r-hGH), entretanto esta terapia apresenta alguns inconvenientes, como a necessidade de frequentes injeções de r-hGH durante um longo período de vida, dependendo da severidade da deficiência, e o alto custo do hormônio, em razão dos dispendiosos processos de purificação. Uma alternativa ao tratamento padrão seria aquele no qual fossem evitados estes tipos de inconvenientes e o processo de liberação da proteína fosse sustentável, por um longo período e promovesse níveis normais e sustentáveis do fator de crescimento semelhante à insulina I (IGF-I), o principal mediador dos efeitos do GH. Uma alternativa é a terapia gênica in vivo, baseada na administração de DNA plasmidial em diversos órgãos/tecidos, seguida de eletroporação. É considerada uma metodologia bastante promissora e que tem sido alvo de vários estudos para diversos tipos de deficiências sistêmicas. Neste trabalho foram realizadas diversas administrações de um plasmídeo contendo o gene do hormônio de crescimento humano, nos músculos quadríceps exposto ou tibial anterior sem exposição, seguidas de eletroporação, em camundongos anões e imunodeficientes (lit/scid) com 40-80 dias de idade, na tentativa de obter uma correção fenotípica do nanismo, mediante a avaliação de parâmetros de crescimento. A administração deste plasmídeo no músculo tibial anterior, em camundongos com a idade inicial de 40 dias, foi capaz de proporcionar uma normalização dos níveis de mIGF-I, quando comparados aos dos camundongos não-deficientes de GH. Além disso, foram obtidos valores de catch-up dos parâmetros de crescimento longitudinal de 36-77%. Visando uma maior eficiência na expressão de GH, foram construídos plasmídeos parentais, e a partir destes, foram produzidos minicírculos de DNA com os promotores do CMV e Ubiquitina C e com os cDNAs de hGH e mGH. Estes minicírculos de DNA foram transfectados em células HEK 293 e foram até 2 vezes mais eficientes em relação aos plasmídeos convencionais com o promotor do CMV. Estes dados são bastantes promissores e abrem caminho para ensaios mais eficientes, utilizando este tipo de protocolo de terapia gênica para a DGH, visando uma normalização de todos os parâmetros de crescimento. / The human growth hormone deficiency (GHD) is the most common deficiency related to pituitary hormones. The current therapy is based on daily injections of recombinant human growth hormone (r-hGH). This therapy, however, presents some disadvantages, as the need for frequent injections of r-hGH during a long life time, depending on the deficiency severity and the high cost of this hormone, due to the expensive purification processes. An alternative to the standard treatment should be to avoid these inconveniences via a sustainable hormone release, acting for a long time and providing normal and sustainable levels of insulin-like growth factor-I (IGF-I). A possible alternative is in vivo gene therapy, based on the administration of plasmid DNA in several organs/tissues, followed by electroporation. This methodology is considered very promising and has been the target of many different studies for several types of systemic deficiencies. In the present work several administrations of a plasmid containing the human growth hormone gene were carried out, in the exposed quadriceps or non-exposed tibialis cranialis muscle, followed by electroporation, using immunodeficient dwarf mice 40-80 days old. The goal was to obtain a phenotypic correction of dwarfism, through the evaluation of different growth parameters. The administration of this plasmid, in the tibialis cranialis muscle of 40 day old mice, was able to provide a normalization of mIGF-I levels, when compared to non GHD mice. Furthermore, catch-up increases of longitudinal growth parameters of 36-77% were obtained. Aiming a high efficiency on GH expression, parental plasmids were constructed and from these DNA minicircles were generated with CMV and Ubiquitin C promoter and hGH or mGH cDNA sequences. These DNA minicircles were transfected into HEK 293 cells and were even 2 times moren efficient than conventional plasmids with CMV promoter. This data are very promising and pave the way for more efficient assays utilizing this type of gene therapy protocol for GHD, aiming at a normalization of all growth parameters.

Submitted by (edna.saturno@ufrpe.br) on 2017-03-23T12:40:14Z No. of bitstreams: 1 Bruno Leal Viana.pdf: 1623265 bytes, checksum: 5707cff554bc2506977fb551f2f6b45e (MD5) / Made available in DSpace on 2017-03-23T12:40:14Z (GMT). No. of bitstreams: 1 Bruno Leal Viana.pdf: 1623265 bytes, checksum: 5707cff554bc2506977fb551f2f6b45e (MD5) Previous issue date: 2009-07-27 / The research was conducted at the Experimental Station of the Agronomic Institute of Pernambuco (IPA) located in Itambé, dry rainforest region of Pernambuco. The objective was to estimate the coefficients of repeatability, of determination (R2) and the number of measures needed to predict the real value [using principal component analysis (PCA)] to variable morphophysiological and productive, and the responses dwarf elephant grass pasture under grazing sheep. The experiment was carried out in a randomized block design with five Pennisetum purpureum clones were evaluated: Taiwan A-146 2.27, Taiwan A-146 2.37, Taiwan A-146 2114, Merker Mexico MX 6.31 and Mott. Evaluations were performed during five grazing cycles, from September 2008 to April 2009. Twenty five sheep (42 kg average liveweight) were used in a mobgrazing protocol, leaving the paddock at 30 cm of residual stubble height. The clones were managed under rotational stocking, with 32 days of resting period and three days of grazing period for cycles 1, 2, and 5, and 64 days of resting period and two days ofgrazing period for cycles 3 and 4. Response variables analyzed at pre- and post-grazing included leaf area index, light interception, leaf angle, average sward height, green portion of herbage mass (DM basis). In addition, we estimated net herbage accumulation (ALF), in kg DM ha-1 cycle-1, and net herbage accumulation rate (TALF), in kg DM ha-1 day-1. Data were analyzed by univariate or multivariate analysis of repeated measures over time in the SAS. Means were compared by Tukey test at 5% probability. According to the PCA, for the variables LAI and LI in cycles of shorter period of regrowth, and height of plants in the cycles of higher period of rest is needed only one measurement (R2=0.80), classifying them among the characteristics evaluatedas the easiest prediction in elephant grass clones. Assessments for NHA and NHAR size of dwarf elephant grass, under grazing, need long experimental periods. / Esta pesquisa foi realizada na Estação Experimental do Instituto Agronômico de Pernambuco (IPA), no município de Itambé, Zona da Mata Seca de Pernambuco, com o objetivo de estimar os coeficientes de repetibilidade, de determinação (R2) e o número mínimo de medições necessárias para predizer o valor real [pela análise dos componentes principais (ACP)] para variáveis morfofisiológicas e produtivas, bem como as respostas dos pastos de capim elefante de porte baixo sob o pastejo de ovinos. O experimento foi conduzido no delineamento em blocos casualizados, com cinco clones de Pennisetum purpureum (Taiwan A-146 2.27, Taiwan A-146 2.37, Taiwan-146 2.114, Merker México MX 6.31, e Mott). As avaliações foram realizadas em cinco ciclos de pastejo, compreendidos entre os meses de setembro de 2008 a abril de 2009. Foram utilizados 25 ovinos, com peso médio de 42 kg, como animais pastejadores em “mobgrazing”, buscando-se a altura de 30 cm de resíduo pós-pastejo. Os clones foram manejados sob lotação intermitente, sendo 32 dias de descanso e três de pastejo para os ciclos 1, 2 e 5 e 64 dias de descanso e dois de pastejo para os ciclos 3 e 4. As variáveisanalisadas foram índice de área foliar, interceptação luminosa, ângulos foliares médios realizados, alturas médias do dossel e massa de forragem seca verde (MSV), no pré e pós pastejo. Foram estimados ainda o acúmulo líquido de forragem (ALF), em kg MS ha-1 ciclo-1 e a taxa de acúmulo líquido de forragem (TALF), em kg MS ha-1 dia-1. Os dados foram analisados por meio de análise univariada ou multivariada de medidas repetidas no tempo no SAS. Para comparação das médias foi utilizado o teste de Tukey a 5% de probabilidade. De acordo com a ACP, para as variáveis IAF e IL nos ciclos de menor período de rebrota, e altura média de plantas nos ciclos de maior período de descanso é necessário apenas uma medição (R2=0,80), classificando-as entre às características avaliadas como as de mais fácil predição em clones de capim elefante. Avaliações de ALF e de TALF para capim elefante de porte baixo, sob pastejo, necessitam de períodos experimentais mais longos.

La première partie de ce document résume les arguments astrophysiques permettant de supposer l’existence de matière noire. Le modèle cosmologique ΛCDM y est présenté ainsi que la notion de section efficace d’auto-annihilation de matière noire. Les galaxies naines satellites de la Voie Lactées, sources de notre étude, sont introduites dans un second chapitre. Après un rappel des grandes structures qui composent l’univers, les problématiques liées aux galaxies naines sont abordées : nombre de ces galaxies, distribution de la densité de matière noire en leur sein et forces de marées dues à la Voie Lactée.La seconde partie discute de la modélisation de la densité de matière noire dans les galaxies naines. La méthode employée, utilisant l’équation de Jeans et la dispersion des vitesses projetées des étoiles, y est présentée. Trois profils de matière noire sont retenus : NFW, Burkert et Einasto ainsi que quinze galaxies naines. La production de neutrinos lors de l’auto-annihilation de matière noire est ensuite abordée. Les spectres énergétiques des neutrinos produits sont générés avec le logiciel PYTHIA puis comparé avec d’autres résultats pour le centre galactique. Vingt-trois hypothèses de masse du candidat de matière noire sont choisies, allant de 25 GeV/c2 `a 100 TeV/c2. Cinq canaux d’auto-annihilation sont sélectionnés pour l’analyse : χχ → b¯b, W+W−, τ+τ−, μ+μ−, νμ ¯ νμ. La troisième partie comporte une présentation du détecteur utilisé pour l’étude, le télescope à neutrinos ANTARES. Trois algorithmes de reconstruction développés et utilisés au sein de la collaboration y sont également détaillés : AAFit, BBFit et GridFit. L’analyse des données d’ANTARES ayant pour but de mettre en évidence un excès de neutrinos caractéristique de l’auto-annihilation de matière noire est résumée dans le sixième et dernier chapitre. Aucun excès n’ayant été observé, une limite sur la section efficace d’auto-annihilation de matière noire a été déterminée. / The first part of this document summarizes the astrophysical arguments to suppose the existence of dark matter. The cosmological model ΛCDM is presented as well as the concept of cross section of dark matter self-annihilation. Dwarf galaxies satellites of the Milky Way, the sources of our study are introduced into a second chapter. After recalling the large structures that make up the universe, the issues related to dwarf galaxies are addressed : missing satellites problem, distribution of dark matter density within them and tidal forces due to the Milky Way. The second part discusses the modeling of the dark matter density in dwarf galaxies. The methodology, using the Jeans equation and dispersion of projected stars velocities, is presented. Three dark matter profiles are retained : NFW, Burkert and Einasto and fifteen dwarf galaxies.Neutrino production during the self-annihilation of dark matter is then addressed. The energy spectra of neutrinos are generated with PYTHIA software and compared with other results for the galactic center. Twenty-three assumptions of mass dark matter candidates are chosen, ranging from 25 GeV/c2 100 TeV/c2. Five self-annihilation channels are selected for analysis : χχ → b¯b, W+W− τ+τ− μ+μ− νμ ¯ νμ. The third part includes a presentation of the detector used for the study, the ANTARES neutrino telescope. Three reconstruction algorithms developed and used in collaboration are also detailed : AAFIT, BBFit and GridFit. The analysis of data ANTARES aimed to find a neutrinos excess characteristic of dark matter self-annihilation is summarized in the sixth and final chapter. No excess was observed, a limit on the cross section of dark matter self-annihilation was determined.

<p>Plant height is an important agronomic trait and a major target for crop improvement. Owing to the ease of detection and measurement of plant stature, as well as its high heritability, several height-related mutants have been reported in maize. The genes underlying a few of those mutants have also been identified, with a majority of them related to the biosynthesis or signaling of two key phytohormones - gibberellins (GAs) and brassinosteroids (BRs). However, most other maize dwarfing mutants, and especially those that result from gain-of-function mutations, remain uncharacterized. The present study was undertaken to characterize a novel dominant dwarfing mutant, named <i>D13</i>. This mutant appeared in the M1 population of the inbred B73 that was generated by mutagenesis with ethyl methanesulfonate (EMS). Like most other maize dwarfing mutants, the reduction in <i>D13</i> height was largely due to the compression of the internodes. However, unlike the GA or BR mutants, <i>D13</i> had no defects in the female or male inflorescences. Further, in contrast to the GA and BR mutants, the mesocotyl elongation during etiolation was not impacted in <i>D13</i>. <i>D13</i> seedlings developed red coloration in two to three lowermost leaves. In addition, <i>D13</i> also showed enhanced tillering when the phenotype was very severe. The size of the shoot apical meristem of <i>D13</i> was reduced slightly, and significant aberrations in the structure of vascular bundles in the mutant were observed. All anatomical and phenotypic features of <i>D13</i> were highly exaggerated in homozygous state, indicating the partially dominant nature of the <i>D13</i> mutation. Interestingly, the heterozygous mutants showed remarkable variation in their phenotype, which was maintained across generations. Moreover, the <i>D13</i> phenotype was found to be sensitive to the genetic background, being completely suppressed in Mo17, Oh7B, enhanced in CML322, P39 and changed to different degrees in others. To identify the genetic defect responsible for the <i>D13</i> mutant phenotype, a map-based cloning approach was used, which identified a single base-pair change from G to A (G2976A) in the coding region of a glutamate receptor gene (Zm00001d015007). The G2976A missense mutation resulted in the replacement of alanine with threonine at the location 670. The replaced alanine is highly conserved in glutamate receptors across all domains of life from cyanobacteria to plants to mammals, suggesting a causal relationship between the G2976A substitution and the <i>D13</i> phenotype. To validate this relationship, a targeted EMS-based mutagenesis approach was used to knock-out (inactivate) the <i>D13</i> mutant allele. A suppressor mutant was found in which the <i>D13</i> mutant phenotype reverted to the normal tall phenotype. The sequence of the revertant allele, designated <i>D13</i>*, revealed that the original <i>D13</i> mutant allele underwent a second G to A mutation (G1520A) to change glycine into aspartic acid at position 473. This intragenic second-site mutation in the <i>D13</i> allele suppressed the function of the <i>D13</i> allele, thereby preventing it from interfering with the function of the wild type allele. To further unveil the genes and underlying mechanisms that enable the <i>D13</i> mutant to confer a dwarf phenotype, transcriptomic and metabolomic analyses of <i>D13</i> mutants were conducted and compared to the wild type sibs. While the omics analysis confirmed that stress responses were upregulated and genes related to shoot system development were downregulated in the mutant, the data did not allow us to pinpoint the underlying mechanisms that connect the <i>D13</i> mutation with its dwarfing phenotype. Furthermore, it remains unclear whether these stress and shoot system-related changes result in the manifestation of <i>D13</i> phenotype, or the dwarf phenotype due to <i>D13</i> mutation activates the stress-related mechanisms. This is the first study that signifies the importance of a glutamate receptor gene in controlling plant height.</p>

Ce mémoire porte sur l'étude des étoiles naines blanches de type DB, dont le spectre est dominé par les raies d’hélium neutre. Des travaux récents ont révélé que les paramètres physiques mesurés à l'aide de la méthode dite spectroscopique —notamment la température effective et la masse de l'étoile — posaient problème pour ce type de naine blanche. Nous avons dans cette étude réexaminé un des ingrédients essentiels de cette méthode, soit le calcul de profils d'élargissement Stark des raies d'hélium neutre. Ce problème fut abordé il y a 25 ans par notre groupe de recherche en utilisant la théorie standard de l'élargissement Stark. Les profils semi-analytiques calculés dans le cadre de cette théorie considèrent les électrons comme étant dynamiques et les ions statiques. Avec l'amélioration de la puissance numérique des ordinateurs, d’autres groupes de recherche ont grandement amélioré le traitement de l'élargissement Stark en produisant des simulations numériques décrivant en détail la dynamique et les interactions des perturbateurs (ions et électrons) près de l'émetteur (l'atome d'hélium dans notre cas). Ils n'ont cependant généré de tables de profils Stark, applicables au calcul de spectres synthétiques d'étoiles naines blanches, que pour deux raies de l'atome d'hélium. Dans ce mémoire, nous décrivons la conception de notre propre environnement de simulation incluant certains aspects importants considérés dans les travaux précédents (unification du traitement des ions et électrons, correction pour la dynamique des ions, transition de la contribution des électrons à l'élargissement, du coeur aux ailes du profil, intégration numérique de l'opérateur quantique d'évolution temporelle de l'hélium perturbé par un champ électrique fluctuant, correction de Debye pour la corrélation du mouvement des perturbateurs chargés, variation de densité locale et réinjection de particules) afin de mieux représenter l'environnement dynamique de l'atome d'hélium. Des étapes intermédiaires, comme la construction de l'espace de simulation et le modèle quasi-statique, nous ont permis de valider cet espace de simulation ainsi que le respect de la statistique du système. Une fois ces étapes de validation franchies, nous avons produit des grilles de profils Stark pour les deux raies les plus importantes de l'atome d'hélium dans le domaine du visible, soit He ɪ λ4471 et He ɪ λ4922, pour des températures entre 10,000 K et 40,000 K et des densités électroniques entre 1 × 10¹⁴ cm⁻³ et 6 × 10¹⁷ cm⁻³. Une comparaison avec d'autres résultats publiés démontre que nos calculs rivalisent avec les meilleurs profils obtenus dans le domaine des simulations numériques de l'élargissement Stark. L'élaboration de cet outil ouvre la voie à la création d'une nouvelle génération de modèles d'atmosphères de naines blanches qui nous permettra de raffiner l'analyse spectroscopique de ces objets. / This thesis deals with the study of white dwarf stars of the DB type, whose spectrum is dominated by neutral helium lines. Recent work has revealed that physical parameters — namely the effective temperature and the stellar mass — measured using the so-called spectroscopic technique are problematic for this type of white dwarf. In this study, we re-examine one of the essential ingredients of this method, namely the calculation of Stark broadening profiles of neutral helium lines. This problem was addressed 25 years ago by our research group using the standard Stark broadening theory. Semi-analytical profiles calculated under this theory consider electrons as dynamic and ions as static. With the improvement of computer numerical power, other research groups have significantly improved the treatment of Stark brodening by producing numerical simulations describing in detail the dynamics and interactions of the perturbers (ions and electrons) near the emitter (the helium atom in our case). However, they generated Stark profile tables, applicable to the computation of synthetic spectra for white dwarf stars, for only two lines of the helium atom. In this thesis, we describe the creation of our own simulation environment including some important aspects considered in previous work (unification of ion and electron treatment, correction for ion dynamics, transition of the electron contribution to broadening from the core to the wings of the profile, numerical integration of the quantum operator of the time evolution of helium perturbed by a fluctuating electric field, Debye correction for the correlation of the motion of charged perturbers, local density variation and particle reinjection) in order to better represent the dynamical environment of the helium atom. Intermediate steps, such as the construction of the simulation space and the quasi-static model, allowed us to validate this simulation space and the respect of the system statistics. Once these validation steps were completed, we produced grids of Stark profiles for the two most important lines of the helium atom in the optical, namely He ɪ λ4471 et He ɪ λ4922, for temperatures between 10,000 K and 40,000 K and electronic densities between 1 × 10¹⁴ cm⁻³ and 6 × 10¹⁷ cm⁻³. A comparison with other published results shows that our calculations rival the best profiles obtained in the field of numerical simulations of Stark broadening. The development of this tool paves the way for the creation of a new generation of white dwarf atmosphere models that will allow us to refine the spectroscopic analysis of these objects.

No description available.

This thesis considers the understudied issue of genetic engineering as it has been deployed in the literature of the late 20th century. With reference to the concept of the enlightened gender hybridity of Cyborg theory and an eye to ecocritical implications, I read four texts: Joan Slonczewski's 1986 science fiction novel A Door Into Ocean, Octavia Butler's science fiction trilogy Lilith's Brood – originally released between 1987 and 1989 as Xenogenesis – Simon Mawer's 1997 literary novel Mendel's Dwarf, and the first two books in Margaret Atwood's speculative fiction MaddAddam series: 2003's Oryx and Crake and 2009's The Year Of the Flood. I argue that the inclusion of genetic engineering has changed as the technology moves from science fiction to science fact, moving from the fantastic to the mundane. Throughout its recent literary history, genetic engineering has played a role in complicating questions of sexuality, paternity, and the division between nature and culture. It has also come to represent a nexus of potential cultural change, one which stands to fulfill the dramatic hybridity Haraway rhapsodized in her "Cyborg Manifesto" while also containing the potential to disrupt the ecocritical conversation by destroying what we used to understand as nature. Despite their four different takes on the issue, each of the texts I read offers a complex vision of utopian hopes and apocalyptic fears. They agree that, for better or for worse, genetic engineering is forever changing both our world and ourselves.

No description available.

Here I study the “plasma interactions with icy bodies in the solar system”, that is, my quest to understand the fundamental processes that govern such interactions. By using numerical modelling combined with in situ observations, one can infer the internal structure of icy bodies and their plasma environments. After a broad overview of the laws governing space plasmas a more detailed part follows. This contains the method on how to model the interaction between space plasmas and icy bodies. Numerical modelling of space plasmas is applied to the icy bodies Callisto (a satellite of Jupiter), the dwarf planet Ceres (located in the asteroid main belt) and the comet 67P/Churyumov-Gerasimenko. The time-varying magnetic field of Jupiter induces currents inside the electrically conducting moon Callisto. These create magnetic field perturbations thought to be related to conducting subsurface oceans. The flow of plasma in the vicinity of Callisto is greatly affected by these magnetic field perturbations. By using a hybrid plasma solver, the interaction has been modelled when including magnetic induction and agrees well with magnetometer data from flybys (C3 and C9) made by the Galileo spacecraft. The magnetic field configuration allows an inflow of ions onto Callisto’s surface in the central wake. Plasma that hits the surface knocks away matter (sputtering) and creates Callisto’s tenuous atmosphere. A long term study of solar wind protons as seen by the Rosetta spacecraft was conducted as the comet 67P/Churyumov-Gerasimenko approached the Sun. Here, extreme ultraviolet radiation from the Sun ionizes the neutral water of the comet’s coma. Newly produced water ions get picked up by the solar wind flow, and forces the solar wind protons to deflect due to conservation of momentum. This effect of mass-loading increases steadily as the comet draws closer to the Sun. The solar wind is deflected, but does not lose much energy. Hybrid modelling of the solar wind interaction with the coma agrees with the observations; the force acting to deflect the bulk of the solar wind plasma is greater than the force acting to slow it down. Ceres can have high outgassing of water vapour, according to observations by the Herschel Space Observatory in 2012 and 2013. There, two regions were identified as sources of water vapour. As Ceres rotates, so will the source regions. The plasma interaction close to Ceres depends greatly on the source location of water vapour, whereas far from Ceres it does not. On a global scale, Ceres has a comet-like interaction with the solar wind, where the solar wind is perturbed far downstream of Ceres. / Här studerar jag “plasmaväxelverkan med isiga kroppar i solsystemet”, det vill säga, min strävan är att förstå de grundläggande processerna som styr sådana interaktioner. Genom att använda numerisk modellering i kombination med observationer på plats vid himlakropparna kan man förstå sig på deras interna strukturer och rymdmiljöer. Efter en bred översikt över de fysiska lagar som styr ett rymdplasma följer en mer detaljerad del. Denna innehåller metoder för hur man kan modellera växelverkan mellan rymdplasma och isiga kroppar. Numerisk modellering av rymdplasma appliceras på de isiga himlakropparna Callisto (en måne kring Jupiter), dvärgplaneten Ceres (lokaliserad i asteroidbältet mellan Mars och Jupiter) och kometen 67P/Churyumov-Gerasimenko. Det tidsvarierande magnetiska fältet kring Jupiter inducerar strömmar inuti den elektriskt ledande månen Callisto. Dessa strömmar skapar magnetfältsstörningar som tros vara relaterade till ett elektriskt ledande hav under Callistos yta. Plasmaflödet i närheten av Callisto påverkas i hög grad av dessa magnetfältsstörningar. Genom att använda en hybrid-plasma-lösare har växelverkan modellerats, där effekten av magnetisk induktion har inkluderats. Resultaten stämmer väl överens med magnetfältsdata från förbiflygningarna av Callisto (C3 och C9) som gjordes av den obemannade rymdfarkosten Galileo i dess bana kring Jupiter. Den magnetiska konfigurationen som uppstår möjliggör ett inflöde av laddade joner på Callistos baksida. Plasma som träffar ytan slår bort materia och skapar Callistos tunna atmosfär. En långtidsstudie av solvindsprotoner sett från rymdfarkosten Rosetta utfördes då kometen 67P/Churyumov-Gerasimenko närmade sig solen. Ultraviolett strålning från solen joniserar det neutrala vattnet i kometens koma (kometens atmosfär). Nyligt joniserade vattenmolekyler plockas upp av solvindsflödet och tvingar solvindsprotonernas banor att böjas av, så att rörelsemängden bevaras. Denna effekt ökar stadigt då kometen närmar sig solen. Solvinden böjs av kraftigt, men förlorar inte mycket energi. Hybridmodellering av solvindens växelverkan bekräftar att kraften som verkar på solvinden till störst del får den att böjas av, medan kraften som verkar till att sänka dess fart är mycket lägre. Ceres har enligt observationer av rymdteleskopet Herschel under 2012 och 2013 haft högt utflöde av vattenånga från dess yta. Där har två regioner identifierats som källor för vattenångan. Eftersom Ceres roterar kommer källornas regioner göra det också. Plasmaväxelverkan i närheten av Ceres beror i hög grad på vattenångskällans placeringen, medan det inte gör det långt ifrån Ceres. På global nivå har Ceres en kometliknande växelverkan med solvinden, där störningar i solvinden propagerar långt nedströms från Ceres.

Les pulsateurs compacts sont des étoiles présentant des variations intrinsèques de luminosité dont les gravités de surface sont supérieures à 100,000 cm/s² On retrouve parmi ces objets deux familles des sous-naines chaudes de type B (sdB) pulsantes et quatre familles distinctes de naines blanches pulsantes. Dans le but d'observer les pulsations de tels objets pour ensuite analyser leur propriétés grâce à l'astéroséismologie, l'Université de Montréal, en collaboration avec le Imaging Technology Laboratory (ITL - University of Arizona), a développé la caméra Mont4K (Montreal4K) CCD qui est, depuis le printemps 2007, le principal détecteur employé au télescope Kuiper de 1.55 m du Mt Bigelow (Steward Observatory, University of Arizona). à l'aide de ce montage, des observations ont été menées pour quelques-uns de ces pulsateurs compacts. La première cible fut HS 0702+6043, un pulsateur hybride. Une importante mission pour cet objet, réalisée du 1er novembre 2007 au 14 mars 2008, a permis d'identifier 28 modes de pulsations pour cet objet en plus de mettre en évidence pour certains de ces modes d'importantes variations d'amplitude. Deux autres cibles furent les naines blanches pulsantes au carbone de type « Hot DQ » SDSS J220029.08-074121.5 et SDSS J234843.30-094245.3. Il fut possible de montrer de façon indirecte la présence d'un fort champ magnétique à la surface de J220029.08-074121.5 grâce à la présence de la première harmonique du mode principal. En outre, pour ces deux cibles, on a pu conclure que celles-ci font bel et bien partie de la classe des naines blanches pulsantes au carbone. / Compact pulsators are stars with surface gravities larger than 100,000 cm/s² showing intrisinc luminosity variations. Six different classes of such objects are known, including two pulsating hot subdwarf (sdB), and four pulsating white dwarf classes. In order to observe their pulsations and further analyze their properties through asteroseismology, the Universit\'e de Montr\'eal, in collaboration with the University of Arizona Imaging Instrument Laboratory, developed the Mont4K (Montreal4K) CCD camera which is the primary science detector of the Kuiper 1.55 m telescope at Mt Bigelow since Spring 2007. With this setup, several compact pulsators were targeted. The first target was the hybrid pulsator HS 0702+6043, observed from November 1st 2007 to March 14th 2008, for which 28 pulsation modes were isolated. Moreover, it was possible to highlight important amplitude variations in some of these modes. Two Hot DQ white dwarf pulsators, SDSS J220029.08-074121.5 and SDSS J234843.30-094245.3, were also targeted. In the case of J220029.08-074121.5, it was possible to highlight the presence of a strong magnetic field at its surface through the presence of the first harmonic of the main pulsation mode of this object. Furthermore, the follow-up campaigns on J220029.08-074121.5 and J234843.30-094245.3 allowed to classify these two white dwarf as Hot DQ pulsators.