Made available in DSpace on 2016-08-17T18:39:48Z (GMT). No. of bitstreams: 1 5434.pdf: 780828 bytes, checksum: 48a9fc16b08390721a72c2c717a9c379 (MD5) Previous issue date: 2013-08-22 / Orchidaceae is one of the largest and diverse families of angiosperms, that is in almost every type of habitat, except tundras and deserts. They are considered of great ornamental importance, the genus Phalaenopsis has received a great prominence having increaed and its production enlarged in the Gross and inner market This way, the Brazilian floriculture market has a great demand in seedling production, requiring more studies and researches involving biotechnologycal techniques from the development of vases and containers on a prepared substrate, propagation techniques and acclimatization. And with in vitro culture, it is possible that the desirable plant coul be multiplied through several sucbultures, which enables an earlier and new cultivation available more quickly for commercial use. The luminosity is another factor that is gaining prominence in the productivity of orchids, the fact that the quality of light affects directly the growth and development of plants grown in vitro and/or ex vitro. The present work had as objective to anlyze the growth of in vitro and acclimatization in the two cultivations (cv. 6323 and cv. 6546) of orchid Phalaenopsis amabilis Blume, under different lighting spectra. Inicially it occurred the sowing the seedling in the cultivation enviroment MS that were enveloped with different cellophanes: yellow, blue, Green, red, and white. After 60 cultivation days it was performed an statistical evaluation on the seedling. Afterward, they were put in collective vases to the phase of acclimatization, and those ones stand for more three months. Through analyze the biometric data it can be observed that the growing in vitro and ex vitro of Phalaenopsis amabilis was influenced by many different spectra lights, considering that the various results of this influence from the genotype. It can be observed that the blue spectrum performed a great performance on cv. 6323 and on the Green spectrum cv. 6546. / Orchidaceae é uma das maiores e diversificadas famílias de angiospermas, que ocupam quase todo tipo de habitat, exceto tundras e regiões desérticas. São consideradas de grande importância ornamental, principalmente as do gênero Phalaenopsis que tem recebido grande destaque, e sua produção aumentada no mercado interno e externo. Dessa forma, o mercado florícola brasileiro teve uma grande demanda na produção de mudas, exigindo mais estudos e pesquisas biotecnológicas que envolvessem técnicas desde o desenvolvimento de vasos e recipientes, a substratos, formas de propagação e aclimatação. Nesse ínterim, com a cultura in vitro, é possível obter a partir de uma planta de interesses desejáveis, a multiplicação desta em vários subcultivos, que possibilita que uma nova cultivar esteja disponível mais rapidamente para uso comercial. A luminosidade é outro fator que vem ganhando destaque na produtividade de orquídeas frente à sua influência direta no crescimento e desenvolvimento de plantas cultivadas in vitro e/ou ex vitro. O presente trabalho teve como objetivo analisar o crescimento in vitro e a aclimatação de dois cultivares (cv. 6323 e cv. 6546) da orquídea Phalaenopsis amabilis, sob diferentes espectros luminosos. Inicialmente, ocorreu a semeadura da plântula em meio de cultura MS que foram envelopados com diferentes cores de celofane: amarelo, azul, verde, vermelho e o controle. Passados 60 dias de cultivo, foi feita a avaliação estatística das plântulas. Posteriormente, foram envasadas em vasos coletivos para a fase de aclimatação, as quais permaneceram por mais três meses. A partir dos dados biométricos analisados pode-se observar que o crescimento in vitro e ex vitro de Phalaenopsis amabilis foi influenciado pelos diferentes espectros luminosos, sendo os variados resultados desta influência decorrentes do genótipo. Pode se observar que o espectro azul exerceu maior influência sobre o cv. 6323 e o espectro verde sobre o cv. 65496.

Determining the cosmic star formation history of the Universe is fundamental for our understanding of galaxy formation and evolution. While surveys now suggest that the "epoch" of galaxy formation occurred more than 6 billion years ago, our measurements still suff er from signi ficant scatter and uncertainties due to the use of diff erent indicators, dust extinction and the e ffects of cosmic variance in the current samples. Furthermore, understanding galaxy formation and evolution require us to go much beyond simply determining the star formation history of the Universe with high accuracy: what are the physical mechanisms driving the strong evolution that we observe? How does star formation depend on stellar mass and environment and how does that change with cosmic time? This thesis presents both a completely self-consistent determination of the star formation history of the Universe (based on a single, sensitive and well-calibrated star formation indicator up to redshift z ~ 2:3: the H α luminosity) and investigates its drivers by exploring large area surveys (probing a range of environments and overcoming cosmic variance) obtained with the High-redshift Emission Line Survey (HiZELS). HiZELS is a panoramic extragalactic survey using the WFCAM instrument on the 3.8-m UK Infrared Telescope (UKIRT) which utilizes a set of existing and custom-made narrow-band filters in the J, H and K bands to detect emission line galaxies (main targets are H α emitters at z = 0:84, z = 1:47 and z = 2:23) up to z ~ 9 over square degree areas of extragalactic sky. Detailed measurements of the H α luminosity function and its evolution with redshift are presented, revealing a signi ficant luminosity evolution. The clustering properties of H α emitters at high-redshift are quantifi ed and investigated for the first time, revealing that these distant galaxies reside in Milky-Way type dark matter haloes at z ~ 1. Mass and environment are found to have important and inter-dependent roles on star formation at high-z and the results are able to reconcile previously contradictory results in the literature. Furthermore, by conducting a novel double-narrow band survey at z = 1:47, the relationship between the [Oii]3727 and H α emission lines is studied in detail and directly compared to z ~ 0, showing no signifi cant evolution in the dust properties of star-forming galaxies, despite the very strong luminosity evolution. Finally, this thesis also presents the widest search for very distant Ly α emitters at z ~ 9.

SuperKEKB est un collisionneur à très haute luminosité construit pour l’expérience Belle II, constitué d’un anneau de basse énergie (LER) transportant des positrons de 4 GeV et d’un anneau de haute énergie (HER) où circulent des électrons de 7 GeV. Sa mise en service -ou commissioning- se déroulera en trois phases : La phase 1, durant laquelle des faisceaux circulent sans être focalisés au point de collision, a pour but de nettoyer la chambre à vide du gaz résiduel. La seconde phase, où le détecteur Belle II sera en partie installé, permettra le réglage du système de focalisation finale des faisceaux, jusqu’à atteindre une luminosité de 10³⁴ cm⁻² s⁻¹. La troisième phase correspondra au démarrage de l’expérience Belle II avec une luminosité visée de 10³⁵ cm⁻² s⁻¹ à 8×10³⁵ cm⁻² s⁻¹. Dans ce cadre, ma thèse porte sur la conception et la mise en place d’un système permettant le monitorage rapide de la luminosité, système nécessaire pour pouvoir corriger en temps réel les instabilités des faisceaux et ainsi maintenir une luminosité optimale. Afin d’atteindre la haute précision relative souhaitée, de l’ordre de 10⁻³ en 1 ms, la mesure sera basée sur le taux de comptage des particules issues de la diffusion Bhabha radiative à angle nul, processus bien connu et dont la section efficace est importante. Ces particules seront détectées au moyen d’un capteur en diamant, matériau résistant aux radiations et permettant une acquisition très rapide du signal, situé à l’extérieur de la chambre à vide et en aval du point d’interaction. La première partie de cette thèse est consacrée à la recherche des localisations optimales pour le positionnement des capteurs diamants dans chacun des deux anneaux. Au moyen de simulations détaillées, nous avons étudié la dynamique des particules Bhabha lors de leur transport dans les anneaux ainsi que leur interaction avec la matière de la chambre à vide. Ces études ont permis d’ une part d’ identifier un emplacement à 11.9m dans le LER et un autre à 30 m dans le HER, et d’autre part de redéfinir pour l’une d’ entre elle la géométrie locale du tube à vide. La seconde partie, plus expérimentale, s’articule autour de la première phase du commissioning de SuperKEKB et des mesures réalisées au moyen des capteurs diamants que nous avons installés. Dans un premier temps, une étude détaillée des processus de perte single beam (Bremsstrahlung, effet Touschek, diffusion coulombienne) a été réalisée pour le LER en fonction des paramètres du faisceau et du collisionneur (courant, pression, taille transverse des faisceaux). Dans un deuxième temps les résultats de cette étude ont été comparés aux données que nous avons prises de février à juin 2016. Nous avons pu mettre en évidence un bon accord qualitatif et quantitatif entre nos simulations et nos mesures. Cela nous a permis d’estimer que le niveau de bruit de fond attendu dans le cadre des mesures pour le monitorage de la luminosité sera de plus de deux ordres de grandeurs inférieurs au taux du processus Bhabha radiatif à angle nul. / SuperKEKB is a very high luminosity collider dedicated to the Belle II experiment, it consists of a Low Energy Ring (LER) of 4 GeV positrons and a High Energy Ring (HER) of 7 GeV electrons. The commissioning of this machine is split into three phases: phase 1 (single-beam phase) is dedicated to vacuum scrubbing, where beams circulate without focusing at the collision point. Phase 2, for which the major part of the Belle II detector will be installed, will enable the tuning of the final focus system to achieve a luminosity of 10³⁴ cm⁻² s⁻¹. During phase 3, Belle II physics runs will start with an aimed luminosity up to 8×10³⁵ cm⁻² s⁻¹. In this context, the aim of my thesis is to develop and install a fast luminosity monitoring system, which is required for online correction of beam instabilities and maintenance of optimal luminosity. To reach the aimed relative precision of 10⁻³ in 1 ms, the measurement will be based on the radiative Bhabha process at zero photon scattering angle, whose cross-section is large and well-known. These particles will be detected using diamond sensors, resistant to radiation and enabling very fast signal acquisition, to be placed outside of the beam-pipe and downstream of the interaction point. The first part of this work is dedicated to the investigation of the best locations for the diamond sensor positioning in both rings. Using detailed simulations, we studied the dynamics of Bhabha particles during their tracking in the rings and their interaction with the beam pipe material. This led to the identification of two positions, at 11.9 m in LER and at 30 m in HER, and to considering a new geometry for the vacuum pipe in the LER. The second part is related to the phase 1 of the SuperKEKB commissioning and concerns the measurements performed with the diamond sensors that were installed. Single beam loss processes (Bremsstrahlung, Touschek, beam-gas Coulomb scattering) were studied in detail with respect to the LER beam and ring parameters (current, pressure, transverse beam sizes). The results of this study were then compared to the data collected from February to June 2016. We found good qualitative and quantitative agreement between our simulations and measurements. From this we could estimate that the level of background to be expected during luminosity monitoring will be two orders of magnitude smaller than the rate of the radiative Bhabha scattering signal.

This thesis is an investigation into some properties of brown dwarfs using medium-resolution spectroscopy. In the first part of the thesis, I address the issue of parameter degeneracy in brown dwarfs. In the course of my analysis, I derive a gravity-sensitive spectral index which can be used, statistically at least, to differentiate populations of young objects from field dwarfs. The index is also capable of finding the difference between a population of ~1 Myr objects and a population of ~10 Myr objects and may be used to separate low-mass members from foreground and background objects in young clusters and associations. The second part of my thesis is an investigation into the major opacity sources in the atmospheres of late T dwarfs. I look particularly at CH4 and NH3 absorption features in the near-infrared spectra of these objects. In my analysis, I identify new absorption features produced by these molecules. I also correct features which had previously been wrongly identified. This has been made possible by the use of high quality data, together with a new CH4 synthetic line list, which is more complete at these temperatures than any previously available list.

This dissertation is a set of three essays connected by the common theme of our epistemic fragility: the way in which our knowledge – of our own minds, of whether we are in violation of the epistemic and ethical norms, and of the philosophical truths themselves – is hostage to forces outside our control. The first essay, “Are We Luminous?”, is a recasting and defence of Timothy Williamson’s argument that there are no non-trivial conditions such that we are in a position to know we are in them whenever we are in them. Crucial to seeing why Williamson’s anti-luminosity argument succeeds, pace various critics, is recognising that the issue is largely an empirical one. It is in part because of the kind of creatures we are – specifically, creatures with coarse-grained doxastic dispositions – that nothing of interest, for us, is luminous. In the second essay, “What’s in a Norm?”, I argue that such an Anti-Cartesian view in turn demands that epistemologists and ethicists accept the ubiquity of normative luck, the phenomenon whereby agents fail to do what they ought because of non-culpable ignorance. Those who find such a view intolerable – many epistemic internalists and ethical subjectivists – have the option of cleaving to the Cartesian orthodoxy by endorsing an anti-realist metanormativity. The third essay, “The Archimedean Urge”, is a critical discussion of genealogical scepticism about philosophical judgment, including evolutionary debunking arguments and experimentally-motivated attacks. Although such genealogical scepticism often purports to stand outside philosophy – in the neutral terrains of science or common sense – it tacitly relies on various first-order epistemic judgments. The upshot is two-fold. First, genealogical scepticism risks self-defeat, impugning commitment to its own premises. Second, philosophers have at their disposal epistemological resources to fend off genealogical scepticism: namely, an epistemology that takes seriously the role that luck plays in the acquisition of philosophical knowledge.

A long-standing problem in low-mass star formation is the "luminosity problem," whereby protostars are underluminous compared to the accretion luminosity expected both from theoretical collapse calculations and arguments based on the minimum accretion rate necessary to form a star within the embedded phase duration. In this dissertation, I present new research on protostars and the protostellar accretion process that addresses the luminosity problem in the following ways: I report new infrared detections of a very low luminosity protostar in Taurus and use all existing data ranging from the infrared through millimeter wavelengths to constrain radiative transfer models and determine physical properties of the source. I argue that the derived source luminosity is lower than that expected based on the properties of a previously detected molecular outflow driven by this source and suggest that this discrepancy can be resolved by variable rather than constant mass accretion. I report the discovery of a new protostar that is also driving a molecular outflow. Following a similar modeling procedure as above, I show that this source has an even lower luminosity that is once again inconsistent with that expected based on the properties of its outflow, again suggesting variable mass accretion. I present the results of a complete search for all protostars with luminosities less than or equal to that of our Sun in a new infrared survey of nearby star-forming regions. I identify 50 protostars with such luminosities. Only a small fraction (15-25%) of dense cores thought to be starless (not yet collapsing to form stars) in fact harbor low luminosity protostars. The distribution of luminosities of these 50 protostars is inconsistent with a constant protostellar mass accretion rate. I present a set of evolutionary models that start with existing models following the inside-out collapse of singular isothermal spheres and add isotropic scattering off dust grains, a circumstellar disk, two-dimensional envelope structure, mass-loss and the opening of outflow cavities, and a simple treatment of episodic mass accretion. I conclude that episodic mass accretion is both necessary and sufficient to resolve the luminosity problem. / text

We study the galaxy populations in 74 Sunyaev-Zeldovich effect selected clusters from the South Pole Telescope survey, which have been imaged in the science verification phase of the Dark Energy Survey. The sample extends up to z similar to 1.1 with 4 x 10(14)M(circle dot) <= M-200 <= 3 x 10(15)M(circle dot). Using the band containing the 4000 angstrom break and its redward neighbour, we study the colour-magnitude distributions of cluster galaxies to similar to m(*) + 2, finding that: (1) The intrinsic rest frame g - r colour width of the red sequence (RS) population is similar to 0.03 out to z similar to 0.85 with a preference for an increase to similar to 0.07 at z = 1, and (2) the prominence of the RS declines beyond z similar to 0.6. The spatial distribution of cluster galaxies is well described by the NFW profile out to 4R(200) with a concentration of c(g) = 3.59(-0.18)(+0.20), 5.37(-0.24)(+0.27) and 1.38(-0.19)(+0.21) for the full, the RS and the blue non-RS populations, respectively, but with similar to 40 per cent to 55 per cent cluster to cluster variation and no statistically significant redshift or mass trends. The number of galaxies within the virial region N-200 exhibits a mass trend indicating that the number of galaxies per unit total mass is lower in the most massive clusters, and shows no significant redshift trend. The RS fraction within R-200 is (68 +/- 3) per cent at z = 0.46, varies from similar to 55 per cent at z = 1 to similar to 80 per cent at z = 0.1 and exhibits intrinsic variation among

No description available.

We present measurements of the clustering of galaxies as a function of their stellar mass in the Baryon Oscillation Spectroscopic Survey. We compare the clustering of samples using 12 different methods for estimating stellar mass, isolating the method that has the smallest scatter at fixed halo mass. In this test, the stellar mass estimate with the smallest errors yields the highest amplitude of clustering at fixed number density. We find that the PCA stellar masses of Chen et al. clearly have the tightest correlation with halo mass. The PCA masses use the full galaxy spectrum, differentiating them from other estimates that only use optical photometric information. Using the PCA masses, we measure the large-scale bias as a function of M-* for galaxies with logM(*) >= 11.4, correcting for incompleteness at the low-mass end of our measurements. Using the abundance matching ansatz to connect dark matter halo mass to stellar mass, we construct theoretical models of b(M-*) that match the same stellar mass function but have different amounts of scatter in stellar mass at fixed halo mass, sigma(logM*). Using this approach, we find sigma(logM*) = 0.18(+0.01) (-0.02). This value includes both intrinsic scatter as well as random errors in the stellar masses. To partially remove the latter, we use repeated spectra to estimate statistical errors on the stellar masses, yielding an upper limit to the intrinsic scatter of 0.16 dex.

CoordenaÃÃo de AperfeiÃoamento de NÃvel Superior / Sementes de espÃcies iniciais sÃo sensÃveis à luminosidade e sua germinaÃÃo à fortemente inibida pela luz filtrada pela vegetaÃÃo. As sementes das espÃcies tardias nÃo requerem luz e a germinaÃÃo à reforÃada por luz vermelho extremo. Os principais fatores ambientais que podem influenciar no processo germinativo sÃo: luz, temperatura e teor da Ãgua. Baseado nas premissas da sucessÃo ecolÃgica, esse estudo tem como objetivos avaliar as respostas ecofisiolÃgicas da germinaÃÃo das sementes de sabià (Mimosa caesalpiniifolia Benth.) em relaÃÃo à temperatura, luminosidade e dessecaÃÃo, para posterior introduÃÃo da espÃcie em programas de recuperaÃÃo de Ãreas degradadas. As anÃlises foram feitas com sementes coletadas na Fazenda Experimental do Vale do Curu da Universidade Federal do Cearà â UFC, no municÃpio de Pentecoste â CE. Determinou-se a biometria de frutos e sementes e foi avaliada a germinaÃÃo em diferentes temperaturas (5ÂC, 10ÂC, 15ÂC, 20ÂC, 25ÂC, 30ÂC, 35ÂC, 40ÂC, 45ÂC e 10-40ÂC), tipos de luminosidade (luz branca, vermelha, vermelho extremo e escuro) e teores de Ãgua (9,04%, 6,06%, 4,68%, 3,54%, 3,10% e 3,07%). No experimento de biometria de frutos e sementes os dados foram submetidos à anÃlise descritiva. Os experimentos de temperatura, luminosidade e teor de Ãgua foram conduzidos em delineamento inteiramente casualizado. Verificou-se que as sementes possuem maior porcentagem de germinaÃÃo na temperatura de 25ÂC e germinam na faixa de temperatura de 10-40ÂC. A germinaÃÃo das sementes à considerada como indiferente a luminosidade e controlada pelo fitocromo A por meio da resposta de fluÃncia muito baixa (RFMB). As sementes nÃo sofrem danos a baixos nÃveis de teor de Ãgua e sÃo classificadas como ortodoxas. / Initial seed species are sensitive to light and their germination is strongly inhibited by light filtered by vegetation. The seeds of the later successional species do not require light and the germination is enhanced by far red light. The main environmental factors that can influence the germination process are: light, temperature and water potential. Based on the assumptions of ecological succession, this study aims to evaluate the ecophysiologicals responses of seed germination of sabià (Mimosa caesalpiniifolia Benth.) in relation to temperature, light and desiccation, for later specie introduction to recovery programs in degraded areas. The analyzes were performed with seeds collected at the Vale do Curu Experimental Farm of Federal University of Cearà - UFC, Pentecoste city â CearÃ. It was determined biometrics fruit and seed and germination was evaluated at different temperatures (5ÂC, 10ÂC, 15ÂC, 20ÂC, 25ÂC, 30ÂC, 35ÂC, 40ÂC, 45ÂC and 10-40  C), types of light (white light, red light, far red light and dark) and humidities (9.04%, 6.06%, 4.68%, 3.54%, 3.10% and 3.07%). Experiment of biometrics fruit and seed the data were analyzed descriptively. The experiments of temperature, light and humidity content were conducted in a completely randomized design. It was found that the seeds have a higher germination rates at 25ÂC and germinated in the temperature range of 10-40ÂC. Seed germination is considered indifferent to light and controlled by the phytochrome using the response very low fluence (RFMB). And the seeds not suffer damage to low levels of humidity content and were classified as orthodox.