Bien qu’elles ne disposent pas de muscles, les plantes ont réussi à développer un nombre remarquable de mécanismes permettant de créer des mouvements rapides, du repliement rapide des feuilles de mimosa pudica à la dispersion de graines par explosion. Parmi ces exemples spectaculaires qui ont depuis longtemps fasciné les scientifiques, la plante carnivore dionée, dont les feuilles se referment en une fraction de secondes pour capturer des insectes, fait figure de paradigme. Récemment, nous avons montré que ce mouvement met en jeu une instabilité de flambage élastique, due à la forme de coque mince des feuilles du piège. Cependant, l’origine microscopique du mouvement qui permet à la plante de franchir le seuil d’instabilité et de changer activement sa courbure reste méconnue. Dans cette thèse nous étudions ce mouvement actif en utilisant un dispositif micro-fluidique, la sonde de pression, qui donne accès directement aux paramètres élastiques et hydrodynamiques à l’échelle de la cellule (pression osmotique, perméabilité cellulaire, élasticité de la paroi, ...). Nos résultats remettent en question le rôle des flux d’eau d’origine osmotique souvent mis en avant pour expliquer la fermeture active du piège de la dionée. De plus, nous développons un dispositif de micro indentation original utilisant un rhéomètre, pour mesurer la réponse locale des tissus et les propriétés mécaniques des épidermes interne et externe. Nous mesurons une signature claire du mouvement actif de la dionée, et fournissons ainsi de nouveaux arguments pour discuter le mécanisme de fermeture, et plus généralement les mouvements rapides dans les plantes. / Although they lack muscle, plants have evolved a remarkable range of mechanisms to create rapid motion, from the rapid folding of sensitive plants to seed dispersal. Of these spectacular examples that have long fascinated scientists, the carnivorous plant Venus flytrap, whose leaves snap together in a fraction of second to capture insects, has long been a paradigm for study. Recently, we have shown that this motion involves a snap-buckling instability due to the shell-like geometry of the leaves of the trap. However, the origin of the movement that allows the plant to cross the instability threshold and actively bend remains largely unknown. In this study, we investigate this active motion using a micro-fluidic pressure probe that gives direct hydraulic and mechanical measurements at the cellular level (osmotic pressure, cell membrane permeability, cell wall elasticity). Our results challenge the role of osmotically-driven water flows usually put forward to explain Venus flytrap’s active closure. Moreover, we developp a micro-indentation original setup using a rheometer, to measure the local tissue response and mechanical properties of the lower and upper epidermis. Then, we detect a clear signature of the active movement in the Venus Flytrap, and thus provide new arguments to discuss this mechanism, and more generally the movements in plants.

The purpose of this study was to discover whether the phrase "men are from Mars, women are from Venus,” from John Gray’s book, had become a meme and to explore what its usage implied. Analysis of 510 references was guided by grounded theory. Coding over a decade of newspaper usage of the phrase into seven emergent themes allowed examination of usage against the theories of gender research, communication research, media research and meme theory research. This analysis revealed that this phrase meets the requirements to be considered a meme, and as a meme it has successfully assisted the survival, evolution and permeance of Gray’s premise that communication differences are inherent and immutable. While this premise is not based on established clinical and academic principles, it is an example of how incorrect and baseless ideas can displace good reasoned thinking based on research.

Lightning is an important electrical phenomenon, known to exist in several Solar System planets. Amongst others, it carries information on convection and cloud formation, and may be important for pre-biotic chemistry. Exoplanets and brown dwarfs have been shown to host environments appropriate for the initiation of lightning discharges. In this PhD project, I aim to determine if lightning on exoplanets and brown dwarfs can be more energetic than it is known from Solar System planets, what are the most promising signatures to look for, and if these "exo-lightning" signatures can be detected from Earth. This thesis focuses on three major topics. First I discuss a lightning climatology study of Earth, Jupiter, Saturn, and Venus. I apply the obtained lightning statistics to extrasolar planets in order to give a first estimate on lightning occurrence on exoplanets and brown dwarfs. Next, I introduce a short study of potential lightning activity on the exoplanet HAT-P-11b, based on previous radio observations. Related to this, I discuss a first estimate of observability of lightning from close brown dwarfs, with the optical Danish Telescope. The final part of my project focuses on a lightning radio model, which is applied to study the energy and radio power released from lightning discharges in hot giant gas planetary and brown dwarf atmospheres. The released energy determines the observability of signatures, and the effect lightning has on the local atmosphere of the object. This work combines knowledge obtained from planetary and earth sciences and uses that to learn more about extrasolar systems. My main results show that lightning on exoplanets may be more energetic than in the Solar System, supporting the possibility of future observations and detection of lightning activity on an extrasolar body. My work provides the base for future radio, optical, and infrared search for "exo-lightning".

L’eau est chez Terrence Malick une figure emblématique de la nature, ce dans une certaine continuité avec l’ensemble du cinéma américain le plus populaire (Steven Spielberg). Malick, en dépit d’une formation en philosophie, n’apparaît pas comme une figure isolée dans son pays.La nature se cache (Héraclite). Elle présente un visage insouciant à l’enfance avant de revêtir le masque de l’indifférence à l’âge adulte. Mais l’invisible de la nature traduit moins de l’effroi que du mystère (Jacques Tourneur). L’indifférence cède la place au véritable étonnement philosophique, celui de la création du monde (naissance de Vénus). Le voile de la nature peut susciter de la violence (le monde de la technique de Heidegger). Y renoncer au profit de la contemplation est possible (Henry Hathaway et le film Peter Ibbetson). La posture du retrait sera privilégiée à la force (Minnelli au cinéma, Marc Aurèle ou Leibniz en philosophie). La piscine et le pont illustrent le rapport de distance existant entre l'individu et l’eau. S’agissant de l’eau prise comme symbole de l’écoulement temporel, l’écueil est de l’appréhender comme un motif de dislocation entre les âges de la vie. Elle est dans le même ordre d’idées une figure privilégiée de la mort. Cette illusion peut être écartée par une appréhension renouvelée des âges de la vie, qui ne se succèdent pas mais s’unissent en permanence en une union qui rappelle la leçon de Proust et bien avant lui d’Héraclite, avec son enfant qui joue présenté comme symbole du temps. Le pont figure là encore un symbole de ce temps retrouvé capable de soigner des maux souvent rencontrés dans le cinéma américain (syndromes de Carlotta et Lolita). / Water constitutes with Terrence Malick a fundamental figure representative of nature, in the lineage of the most popular American cinema (Spielberg). Malick, despite the importance of his philosophical culture, appears the contrary of an isolated figure in his country.The main characteristic of nature is to hide (Heraclitus). Nature presents a friendly face to the child and becomes indifferent for the adult. The invisibility of nature in water conveys less fright than a sense of mystery (Jacques Tourneur). Indifference gives way to philosophical wonder linked to the creation of the world from water (the birth of Venus).Violence can respond to the veil (the technical world of Heidegger). But contemplation can replace cold reason (Henry Hathaway and his movie Peter Ibbetson). The idea is not to force nature to deliver its message, but to step back in a way announced by philosophers Marcus Aurelius and Leibniz, and movie maker Minnelli. The swimming pool and the bridge represent two space figures which permit to illustrate the distance between the individual and water.As to water as a symbol of time flowing, the mistake is to understand time as fragmented periods of life without any connection. Water is also a symbol of death. The illusion can vanish when apprehending time in a renewed manner. The ages of life do not follow each other but are permanently combined in a union reminiscent of Proust’s teachings. The bridge represents once more this time newly found able to heal psychological diseases often encountered in American cinema (syndromes of Carlotta and Lolita).

5 Abstract This study is dedicated to evaluating the potential for a novel pathway of abiotic synthesis of phosphine (PH3) from phosphorus trioxide (P4O6) by a photocatalytic mechanism on aerosols. The mechanism might explain the recent possible detection of phosphine on Venus. This scenario has recently been suggested theoretically by our team based on an analogy with methane production form carbon dioxide on acidic photochemically-active surfaces of materials, which may account for a possible source of methane on Mars. Methane, just like phosphine, was suggested as an indicator of life on terrestrial planets, including Mars. The theoretical testing of photochemical phosphine generation suggests that even if this gas is present in the atmosphere of Venus it cannot be considered as an indicator of life until the suggested mechanism is excluded theoretically, or by experimental results, or direct evidence of life on Venus. This thesis will be followed by preparation of sophisticated experiments and intensive laboratory research addressing this. Furthermore, the role of nitrous oxide as another false positive biosignature was evaluated in this study. The presence of nitrous oxide can also be explained by processes other than biological, particularly on early planets. This study specifically demonstrates the...

La socialisation organisationnelle est un long processus à travers lequel les nouveaux venus apprennent tout ce qui concerne la nouvelle organisation dont ils deviendront membres. Les thèmes abordés concernaient : le nouveau travail, l’expérience de la socialisation et les éléments de motivation. Cette étude introduit la satisfaction du besoin psychologique comme résultat proximal de la socialisation organisationnelle, comme suggéré dans l’étude 1. Le soutien social organisationnel, c’est-à-dire le rôle des agents de socialisation, a été ajouté aux tactiques organisationnelles de socialisation comme variable indépendante. Afin de renforcer les résultats et pour prendre en compte les effets externes, deux variables modératrices (le capital psychologique et la proactivité du nouveau venu) ont été introduites. Une relation positive a été trouvée entre les tactiques organisationnelles de socialisation et la satisfaction des besoins psychologiques, ce qui fait de cette dernière un résultat proximal de la socialisation. La performance au travail et l’implication affective sont positivement influencées par les tactiques organisationnelles de socialisation et le soutien social des agents de socialisation. Il a été établi que capital psychologique des nouveaux venus renforce les relations entre les tactiques organisationnelles de socialisation, le soutien social des agents de socialisation (variables indépendantes) et la satisfaction des besoins psychologiques ; également, la proactivité des nouveaux venus renforce les relations entre la satisfaction des besoins psychologiques et les variables dépendantes à savoir la performance au travail et l’implication affective. / Organizational socialization is a dynamic process by which newcomers learn and adjust to attitudes and behaviors needed to assume their new organizational roles. Nowadays managing newcomers becomes a challenge for organizations as they demand more from their organization, and push organizations to invest time and resources for their adjustment. The present study introduces psychological needs satisfaction in the scope of organizational socialization research. 34 newcomers were interviewed about their new job, socialization experience and required motivational elements by using the critical incident technique. The results showed that newcomers’ psychological needs fulfillment was helping the success of the organizational socialization process. Subsequently, a quantitative study was conducted to test the theoretical model. A positive relationship was found between organizational socialization tactics and psychological need satisfaction proving it as a proximal outcome of socialization. Distal outcomes i.e. job performance and affective commitment were also positively influenced by organizational socialization tactics and organizational social support from socialization agents. Further, it was found that newcomers’ psychological capital (moderating variable at T1) strengthened the relationship between socialization resources (i.e. organizational socialization tactics and organizational social support) and newcomer’s psychological needs satisfaction; and that newcomers’ proactivity (moderating variable at T2) strengthened the relationship between psychological needs satisfaction and job outcomes, i.e. performance and affective commitment.

Imagine a theater. Build one in your mind. I do not care if it is the largest theater in the universe or if it is the size of a shoebox. The theater can be an elaborate construction with gilded cherubs and priceless jewels. If you would prefer the theater to be a minimal design, imagine it that way. Maybe the theater is made out of glass or crystal. You can be all alone in the theater or maybe you are seated next to an alien, a cave man, or a robot. As the curtain rises an enormous pipe organ is spewing out J.S. Bach’s Toccata and Fugue in D minor. The sound is colossal. The stage is designed to look like a filthy and bleak art studio. Sculptures that look like decaying flesh hang from the ceiling. Papers and dirty painting rags are scattered all over the floor. A roach crawls towards some moldy food in the wastebasket. A piece of beef jerky sits next to a pile of paint tubes and paintbrushes. Canvases are stacked against the wall. Dried paint is splattered everywhere. A woman enters stage left. As she begins to speak, the music fades… “My most recent paintings are meant to serve as gateways between daily life and an exotic utopian fantasy. These strange psychological spaces function as portals into a new frontier inhabited with the most stupendous creatures. Active volcanoes, carnivorous plants, terrible lizards, pink Chihuahuas, flesh-eating insects, unidentified flying objects, and a host of other amazing things coexist in this cruel tropical paradise. “Everything I do is a self-portrait and a disguise. I imagine the characters in my paintings to be mutant clones. The act of painting is like looking in the mirror. I like to spend most of my time doing one or the other. I am driven by an insatiable urge to see what I truly look like. I suffer from an unfulfilled desire to meet myself. I am frustrated with impressions and reflections. These confessions reveal my work as possibly the most disgusting display of narcissism in the entire history of art. “The act of painting is an absurd and self-indulgent enterprise. I paint with the ridiculous and frivolous purpose of delighting the eye. Nevertheless, my hope is that my paintings capture an important aspect of my utopian fantasy with their sumptuous surroundings embellished with rainbows, natural disasters, butterflies, exotic grasses and bizarre costumes. “My paintings can be read on many different levels from surface to deep allegory. The finished product is the result of hours upon hours of painting, pondering, and dreaming. Below the surface lies a nauseating abyss. “My work is a delicious feast for the aesthetic consumer. I am a villainous mad scientist with a hunger for immortality. My eyes are gluttonous fools. I am a mystery and a deception. Vermillion is my opulent fetish. Lemon yellow is my nemesis.” The music grows louder again. The woman begins to cackle. She then takes a deep breath and a deeper and more dramatic bow. She exits stage right--you find that you want to applaud--but unfortunately, this story is not over. I suggest that you get yourself a snack like some popcorn, chocolate, or gummy bears before reading any further. The curtain slowly and elegantly comes down.

<p>Syftet med uppsatsen har varit att få en uppfattning om hur andra ser på Afrodite, om de beskriver henne som i myterna eller om det finns en annan bild av henne, men också att få en beskrivning av Afrodite som en kvinna av idag och vilka egenskaper hon i sådana fall har.</p><p>Empiriska data har samlats in med hjälp av kvalitativ intervju med öppna frågeställningar. Utgångspunkten har varit en bild av en staty med Afrodite, Pan och Eros och informanterna fick beskriva vad de såg och kände inför bilden. Därefter följde en frågeställning om vem Afrodite-kvinnan av idag är. Förutom bilden av statyn diskuterade informanterna Afrodite som barn och tonåring, kvinnan Afrodite, kärlek och sexualitet, yrke och makt, man och barn, utseende och skönhet.</p>

In the following work, the MAVRIC sequence of the Scale6.1 code package was tested for its efficacy in calculating a wide range of shielding parameters with respect to HTGRs. One of the NGNP designs that has gained large support internationally is the VHTR. The development of the Scale6.1 code package at ORNL has been primarily directed towards supporting the current United States' reactor fleet of LWR technology. Since plans have been made to build a prototype VHTR, it is important to verify that the MAVRIC sequence can adequately meet the simulation needs of a different reactor technology. This was accomplished by creating a detailed model of the VHTR power plant; identifying important, relevant radiation indicators; and implementing methods using MAVRIC to simulate those indicators in the VHTR model. The graphite moderator used in the design shapes a different flux spectrum than water-moderated reactors. The different flux spectrum could lead to new considerations when quantifying shielding characteristics and possibly a different gamma-ray spectrum escaping the core and surrounding components. One key portion of this study was obtaining personnel dose rates in accessible areas within the power plant from both neutron and gamma sources. Additionally, building from professional and regulatory standards a surveillance capsule monitoring program was designed to mimic those used in the nuclear industry. The high temperatures were designed to supply heat for industrial purposes and not just for power production. Since tritium, a heavier radioactive isotope of hydrogen, is produced in the reactor it is important to know the distribution of tritium production and the subsequent diffusion from the core to secondary systems to prevent contamination outside of the nuclear island. Accurately modeling indicators using MAVRIC is the main goal. However, it is almost equally as important for simulations to be carried out in a timely manner. MAVRIC uses the discrete ordinates method to solve the fixed-source transport equation for both neutron and gamma rays on a crude geometric representation of the detailed model. This deterministic forward solution is used to solve an adjoint equation with the adjoint source specified by the user. The adjoint solution is then used to create an importance map that can weight particles in a stochastic Monte Carlo simulation. The goal of using this hybrid methodology is to provide complete accuracy with high precision while decreasing overall simulation times by orders of magnitude. The MAVRIC sequence provides a platform to quickly alter inputs so that vastly different shielding studies can be simulated using one model with minimal effort by the user. Each separate shielding study required unique strategies while looking at different regions in the VHTR plant. MAVRIC proved to be effective for each case.

Syftet med uppsatsen har varit att få en uppfattning om hur andra ser på Afrodite, om de beskriver henne som i myterna eller om det finns en annan bild av henne, men också att få en beskrivning av Afrodite som en kvinna av idag och vilka egenskaper hon i sådana fall har. Empiriska data har samlats in med hjälp av kvalitativ intervju med öppna frågeställningar. Utgångspunkten har varit en bild av en staty med Afrodite, Pan och Eros och informanterna fick beskriva vad de såg och kände inför bilden. Därefter följde en frågeställning om vem Afrodite-kvinnan av idag är. Förutom bilden av statyn diskuterade informanterna Afrodite som barn och tonåring, kvinnan Afrodite, kärlek och sexualitet, yrke och makt, man och barn, utseende och skönhet.