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The intriguing exoplanet candidate KIC 12557548b is believed to have a comet-like tail of dusty debris trailing a small rocky planet. The tail of debris scatters up to 1.3% of the stellar light in the Kepler observatory's bandpass (0.42-0.9 mu m). Observing the tail's transit depth at multiple wavelengths can reveal the composition and particle size of the debris, constraining the makeup and lifetime of the sub-Mercury planet. Early dust particle size predictions from the scattering of the comet-like tail pointed toward a dust size of similar to 0.1 mu m for silicate compositions. These small particles would produce a much deeper optical transit depth than near-infrared transit depth. We measure a transmission spectrum for KIC 12557548b using the SpeX spectrograph (covering 0.8-2.4 mu m) simultaneously with the MORIS imager taking r' (0.63 mu m) photometry on the Infrared Telescope Facility for eight nights and one night in H band (1.63 mu m) using the Wide-field IR Camera at the Palomar 200 inch telescope. The infrared spectra are plagued by systematic errors, but we argue that sufficient precision is obtained when using differential spectroscopic calibration when combining multiple nights. The average differential transmission spectrum is flat, supporting findings that KIC 12557548b's debris is likely composed of larger particles greater than or similar to 0.5 mu m for pyroxene and olivine and greater than or similar to 0.2 mu m for iron and corundum. The r' photometric transit depths are all below the average Kepler value, suggesting that the observations occurred during a weak period or that the mechanisms producing optical broadband transit depths are suppressed.

The Snedden lab has been studying a family of Ca2+-binding proteins from Arabidopsis that are related to the prototypical Ca2+ sensor calmodulin (CaM) and are termed CMLs (CaM-like proteins). Previous work on CML42 demonstrated that it displays biochemical properties typical of Ca2+ sensors and interacts in vitro with KIC (KCBP-interacting Ca2+-binding protein), a protein known to function in trichome branching. In the present study, I investigated whether CML42 is also involved in trichome branching. I examined a CML42 T-DNA insertion knockout line (cml42) and found that it exhibits a mutant trichome phenotype with increased branch numbers compared to wildtype plants. All other aspects of cml42 growth and morphology, including root hairs, appeared normal relative to wildtype plants. kic knockout plants did not show any discernible trichome phenotype when compared to wildtype plants, nor did transgenic lines overexpressing CML42. Transgenic plants lacking both CML42 and KIC expression (cml42kic) displayed a cml42 mutant phenotype. The genetic studies suggest that CML42 is a negative regulator of trichome branching. Biochemical analysis on recombinant full-length CML42, C-terminal, and N-terminal fragments, using the fluorescent probe 8-Anilino-1-naphthalenesulfonate (ANS), demonstrated that Ca2+-binding results in a conformational change in CML42 and the exposure of hydrophobic regions, particularly within the C-terminal lobe. Collectively, data from the Snedden Lab support the important role of Ca2+ signalling in trichome branching and morphology. / Thesis (Master, Biology) -- Queen's University, 2009-08-11 14:00:06.008

Made available in DSpace on 2014-12-17T15:15:01Z (GMT). No. of bitstreams: 1 MariaLC_TESE.pdf: 10138137 bytes, checksum: 77bd9c3c6dc76faa3f4dc70c892af4b1 (MD5) Previous issue date: 2014-04-07 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Stellar differential rotation is an important key to understand hydromagnetic stellar dynamos, instabilities, and transport processes in stellar interiors as well as for a better treatment of tides in close binary and star-planet systems. The space-borne high-precision photometry with MOST, CoRoT, and Kepler has provided large and homogeneous datasets. This allows, for the first time, the study of differential rotation statistically robust samples covering almost all stages of stellar evolution. In this sense, we introduce a method to measure a lower limit to the amplitude of surface differential rotation from high-precision evenly sampled photometric time series such as those obtained by space-borne telescopes. It is designed for application to main-sequence late-type stars whose optical flux modulation is dominated by starspots. An autocorrelation of the time series is used to select stars that allow an accurate determination of spot rotation periods. A simple two-spot model is applied together with a Bayesian Information Criterion to preliminarily select intervals of the time series showing evidence of differential rotation with starspots of almost constant area. Finally, the significance of the differential rotation detection and a measurement of its amplitude and uncertainty are obtained by an a posteriori Bayesian analysis based on a Monte Carlo Markov Chain (hereafter MCMC) approach. We apply our method to the Sun and eight other stars for which previous spot modelling has been performed to compare our results with previous ones. The selected stars are of spectral type F, G and K. Among the main results of this work, We find that autocorrelation is a simple method for selecting stars with a coherent rotational signal that is a prerequisite to a successful measurement of differential rotation through spot modelling. For a proper MCMC analysis, it is necessary to take into account the strong correlations among different parameters that exists in spot modelling. For the planethosting star Kepler-30, we derive a lower limit to the relative amplitude of the differential rotation. We confirm that the Sun as a star in the optical passband is not suitable for a measurement of the differential rotation owing to the rapid evolution of its photospheric active regions. In general, our method performs well in comparison with more sophisticated procedures used until now in the study of stellar differential rotation / A rota??o diferencial superficial ? um importante par?metro para a compreens?o do d?namo hidromagn?tico estelar, instabilidades e processos de transportes no interior estelar, bem como fornece subs?dios para um melhor tratamento das mar?s em bin?rias pr?ximas e sistemas estrela-planeta. As miss?es espaciais MOST, CoRoT e Kepler t?m fornecido uma grande e homog?nea quantidade de dados fotom?tricos. O que permite, pela primeira vez, o estudo da rota??o diferencial em amostras estatisticamente robustas cobrindo quase todos os est?gios da evolu??o estelar. Nesta tese, n?s desenvolvemos e apresentamos um m?todo para medir o limite inferior para a amplitude da rota??o diferencial a partir de s?ries fotom?tricas igualmente espa?adas, tais como aquelas obtidas pelas miss?es espaciais supracitadas. O modelo foi concebido para ser aplicado em estrelas do tipo solar cuja modula??o ?tica ? dominada pelo efeito das manchas estelares. As estrelas s?o selecionadas a partir de uma autocorrela??o das s?ries temporais, o que permite uma determina??o precisa dos per?odos de rota??o das manchas. Um modelo simples de duas manchas ? aplicado juntamente com crit?rios de informa??o bayesiana para selecionar, preliminarmente, os intervalos das s?ries temporais que mostram evid?ncias de rota??o diferencial com manchas de ?rea quase constante. A signific?ncia da rota??o diferencial detectada e as medidas de sua amplitude e incertezas s?o obtidas por an?lise a posteriori bayesiana, em uma aproxima??o Monte Carlo via cadeias de Markov (MCMC). Aplicamos nosso m?todo para o Sol e outras oito estrelas para as quais a modelagem de manchas foi anteriormente realizada. As estrelas selecionadas s?o de tipo espectral F, G e K. Obtivemos ent?o a rota??o diferencial e comparamos os resultados obtidos pelo nosso m?todo com aqueles j? conhecidos na literatura. Entre os principais resultados deste trabalho, encontramos que autocorrela??o ? um m?todo simples e eficaz para sele??o de estrelas com um sinal rotacional coerente, pr?-requisito para uma medida de rota??o diferencial por meio de modelagem de manchas. Para uma an?lise adequada de MCMC ? necess?rio levar em considera??o a forte correla??o entre diferentes par?metros existentes na modelagem de manchas. Para a estrela hospedeira de planeta Kepler-30, encontramos um baixo limite para uma amplitude relativa de rota??o diferencial. Tamb?m, confirmamos ainda que o nosso modelo n?o ? adequado para medir a rota??o diferencial do Sol como uma estrela, na banda ?tica, devido ? r?pida evolu??o de suas regi?es fotosf?ricas ativas. Em geral, o nosso modelo funciona bem em compara??o com os mais sofisticados procedimentos at? agora utilizados no estudo da rota??o diferencial estelar

We present a photometric detection of the first brightness dips of the unique variable star KIC 8462852 since the end of the Kepler space mission in 2013 May. Our regular photometric surveillance started in 2015 October, and a sequence of dipping began in 2017 May continuing on through the end of 2017, when the star was no longer visible from Earth. We distinguish four main 1%-2.5% dips, named "Elsie," "Celeste," "Skara Brae," and " Angkor," which persist on timescales from several days to weeks. Our main results so far are as follows: (i) there are no apparent changes of the stellar spectrum or polarization during the dips and (ii) the multiband photometry of the dips shows differential reddening favoring non-gray extinction. Therefore, our data are inconsistent with dip models that invoke optically thick material, but rather they are in-line with predictions for an occulter consisting primarily of ordinary dust, where much of the material must be optically thin with a size scale << 1 mu m, and may also be consistent with models invoking variations intrinsic to the stellar photosphere. Notably, our data do not place constraints on the color of the longer-term "secular" dimming, which may be caused by independent processes, or probe different regimes of a single process.

[pt] O sistema adesivo desempenha um papel importante na restauração dental, uma vez que é o responsável por promover a adesão entre o dente e resina. Apesar do avanço deste material, ele ainda pode apresentar problemas quando atua no tratamento restaurador. Sob ação das cargas de mastigação, os possíveis defeitos presentes na interface adesiva podem atuar como concentradores de tensão. Na presença destas descontinuidades, a interface pode comportar-se de maneira frágil, fraturando abruptamente e comprometer a restauração. Quando essa interface não tem muita resistência à fratura, é caracterizada por baixos valores de tenacidade à fratura, KIc. Portanto, o objetivo do presente estudo foi avaliar, por um método alternativo de testes, a tenacidade à fratura da interface dente / restauração utilizando diferentes sistemas adesivos e resinas compostas. Os terceiros molares foram cortados e restaurados com um entalhe pré-existente. De acordo com o material de restauração (adesivos convencional ou autocondicionante; e resinas compostas híbrida ou nanohíbrida), foram divididos em três grupos. A resistência à fratura foi avaliada por meio de testes de KIc, usando corpos de prova nos quais a zona de processo (região da trinca) é similar à interface de restauração. Após o teste, as superfícies de fratura foram analisadas por microscopia óptica (lupa) e microscopia eletrônica de varredura (MEV) para observar os planos de propagação das trincas nesses ensaios de tenacidade. Análise dos testes mostrou que todos os grupos comportaram-se de maneira semelhante (ruptura frágil), o que foi confirmado pelas análises de superfície. A análise estatística dos valores de KIc para cada grupo indicou haver diferença entre os grupos comparados. Juntamente com a análise qualitativa da média e do desvio padrão, é possível concluir que o material utilizado no Grupo 3 teve um desempenho superior aos outros. / [en] The adhesive system plays an important role in dental restoration, since it is responsible for promoting adhesion between the tooth and the composite resin. Despite the advance of this material, it can still present problems when acting in restorative treatment. Under masticatory loads, the possible flaws present in the adhesive interface can act as stress raisers. In the presence of these discontinuities, the interface can behave fragile, fracturing abruptly and compromising the restoration. When this interface has not much resistance to fracture, is characterized by low values of fracture toughness, KIc. Therefore, the aim of the present study was to evaluate, by an alternative method of testing, the fracture toughness of tooth / restoration interface with different adhesive systems and composite resins. Third molars were cut and restored with a pre-existing crack. According to the restorative material (conventional adhesive or self-etching adhesive, and hybrid or nanohybrid composites), they were divided into three groups. The fracture toughness was measured by KIc testing, using specimens in which the process zone (crack region) is similar to restoration‟s interface. After testing, the fracture surfaces were analyzed by optical microscopy (magnifying glass) and scanning electron microscopy (SEM) to observe the propagation of cracks plans. Analysis of the tests showed that all groups behaved similarly (brittle fracture), which was confirmed by surface analyzes. Statistical analysis of the KIc values for each group indicated difference between the compared groups. With the statistical evaluation and a qualitative analysis of the means and standard deviation was possible to conclude the material used in Group 3 had a better performance than the other groups.

Europe is arguably in need of a more offensive approach towards theencouragement of entrepreneurship and research based product development.Several European initiatives have been initiated towards this aim, one ofwhich is the Knowledge and Innovation Communities (KICs); an initiativeultimately taken by the European Commission. The main purpose of the KICsis to foster innovation and commercialization in Europe by combining forcesof industry and university, much in line with the theory of the TripleHelix. This master’s thesis is a follow up report of a previously conductedRemotely Operated Vehicle (ROV) market analysis, which was a deliverable inthe OTS project; a KIC InnoEnergy initiated project, aiming towards productdevelopment within the ocean energy sector. The purpose of this thesis hasbeen to, on the one hand evaluate how such a multidisciplinary projectworks in practice, the consequences of its design and the coping of theseconsequences, and on the other hand to identify and map prerequisites for asituation regarding if, and how, the project should invite anotherparticipant from industry into a collaboration. Based on a qualitativeanalysis of seven interviews with representatives from both academia andindustry, the conclusions indicated that the structure and future of theOTS/ROV project is perceived as unclear, best remedied by strongermanagement, additional funding, and invitation of a new collaborator. Thedemands for such collaboration mainly include an explicit project plan fromthe external ROV supplier’s point of view, and the sharing of knowledge andequipment of the supplier from the internal members’ point of view.

Atlas Copco Secoroc AB are searching after new bulk materials for drill heads that are used in percussive drilling in order to improve their strength and durability. The aim of this project is to assist Atlas Copco in this search and provide them with further information regarding material properties, alloying elements, suppliers, etc. A literary study was carried out in order to identify materials that had UTS and KIC more than or equal to 1700 MPa and 70 MPa*m1/2, respectively. Materials that fulfilled these criteria were T250 grade maraging steel, Cobalt free maraging steel, High cobalt maraging steel, 300 grade maraging steel, AerMet 100, AF1410, S53, M54, 300M, 4340M and PremoMet. These were categorized into maraging steels, high alloy secondary hardened steels, and low alloy steels, and were then further researched.  The material with the highest combination of UTS and KIC was M54 followed by AerMet 100; while AF1410 had the highest KIC but a low UTS, and PremoMet had the highest UTS but a low KIC. Maraging steels and HASH steels have a similar price range, while low alloy steels are much cheaper.

Atlas Copco Secoroc AB are searching after new bulk materials for drill heads that are used in percussive drilling in order to improve their strength and durability. The aim of this project is to assist Atlas Copco in this search and provide them with further information regarding material properties, alloying elements, suppliers, etc. A literary study was carried out in order to identify materials that had UTS and KIC more than or equal to 1700 MPa and 70 MPa*m^1/2, respectively. Materials that fulfilled these criteria were T250 grade maraging steel, Cobalt free maraging steel, High cobalt maraging steel, 300 grade maraging steel, AerMet 100, AF1410, S53, M54, 300M, 4340M and PremoMet. These were categorized into maraging steels, high alloy secondary hardened steels, and low alloy steels, and were then further researched. The material with the highest combination of UTS and KIC was M54 followed by AerMet 100; while AF1410 had the highest KIC but a low UTS, and PremoMet had the highest UTS but a low KIC. Maraging steels and HASH steels have a similar price range, while low alloy steels are much cheaper.

Accurate knowledge of stellar parameters such as mass, radius, effective temperature, and composition inform our understanding of stellar evolution and constrain theoretical models. Binaries and, in particular, eclipsing binaries make it possible to measure directly these parameters without reliance on models or scaling relations. In this dissertation we derive fundamental parameters of stars in close binary systems with and without (detected) tertiary companions to test and inform theories of stellar and binary evolution. A subsample of 41 detached and semi-detached short-period eclipsing binaries observed by NASA’s Kepler mission and analyzed for eclipse timing variations form the basis of our sample. Radial velocities and spectroscopic orbits for these systems are derived from moderate resolution optical spectra and used to determine individual masses for 34 double-lined spectroscopic binaries, five of which have detected tertiaries. The resulting mass ratio M2/M1 distribution is bimodal, dominated by binaries with like-mass pairs and semi-detached classical Algol systems that have undergone mass transfer. A more detailed analysis of KIC 5738698, a detached binary consisting of two F-type main sequence stars with an orbital period of 4.8 days, uses the derived radial velocities to reconstruct the primary and secondary component spectra via Doppler tomography and derive atmospheric parameters for both stars. These parameters are then combined with Kepler photometry to obtain accurate masses and radii through light curve and radial velocity fitting with the binary modeling software ELC. A similar analysis is performed for KOI-81, a rapidly-rotating B-type star orbited by a low-mass white dwarf, using UV spectroscopy to identify the hot companion and determine masses and temperatures of both components. Well defined stellar parameters for KOI-81 and the other close binary systems examined in this dissertation enable detailed analyses of the physical attributes of systems in different evolutionary stages, providing important constraints for the formation and evolution of close binary systems.