This study consists of two essays. In the first essay, I examine whether the overlap in institutional investors between the supplier and its customer can be an efficient monitoring mechanism in the product market. Using a large sample of supplier–customer relationships for the period 1980–2011, I provide the following evidence. First, a high level of overlapping institutional ownership mitigates the adverse effect of asymmetric interdependence between supplier and customer on their firm performance. Second, relationship-specific investments and partnership duration are identified as underlying channels through which overlapping institutional ownership mitigates the adverse effect of asymmetric interdependence on partners’ performance. Third, overlapping institutional ownership is negatively associated with accounts receivable when the supplier is more financially constrained than the customer, suggesting that overlapping institutional ownership improves the efficiency of trade credit allocation. These findings survive out of a series of robustness checks. The findings of this study highlight that the overlap in institutional investors between supplier and customer plays as an efficient monitoring mechanism in the product market. In the second essay, I examine the informational role of overlapping transient institutional investors who hold stocks of both the firm and its customers in disseminating customer information to the firm’s bond market and document four findings. First, I find that overlapping transient institutional ownership significantly alleviates the prediction of lagged customer-portfolio bond returns to supplier bond returns even after controlling for the interaction effect between stock market and bond market. This finding survives out of a series of robustness checks. The alleviation effect is more pronounced for firms with high customer concentration and low customer industry competition, or with non-investment grade. Second, I find that overlapping transient institutional ownership represents more than a mere proxy for investor attention and leads to information advantage over overlapping institutional bondholders. Third, I find that current customer-portfolio return is significantly associated with the trading volume of overlapping transient institutional investors in the bond market, suggesting that overlapping transient institutional investors indeed take customer information into account when they trade bonds of suppliers. Fourth, I examine the real effect of customer information on bondholders and find that customer bond return is significantly related to the supplier’s future operating performance, which is an important predictor of credit risk. Overall, my results show that overlapping transient institutional shareholders take economically linked information into account when they trade in the bond market and improve the informativeness of bond price. Keywords: supplier–customer relationships, overlapping institutional investors, monitoring mechanism, bond price informativeness

Despite the prevalence of supramolecular architectures derived from metal-ligand or hydrogen-bonding interactions, few studies have focused on the simultaneous use of these two strategies to form discrete metal-ligand hydrogen-bonded (MLHB) assemblies. The design, synthesis, and characterization of 2-quinolone based hybrid subunits, 7-DPQ and 5-PYQ, that contain phosphine and pyridyl metal binding sites, respectively, is reported. Both subunits give two-fold symmetric hydrogen-bonded tectons that assemble with metal precursors to give hybrid MLHB structures. Treatment of [Cp*RhCl2]2 with the 7-DPQ subunit yields hybrid MLHB assemblies with closed topology. 1H diffusion ordered spectroscopy experiments established the stability of the structures in solution, and the measured hydrodynamic radii match those determined crystallographically, suggesting that the closed topology is maintained in solution and the solid state. In order to further explore possible MLHB architectures and test the selectivity boundaries of our quinolone-based subunits we report the selective assembly of 5-PYQ with mono- and bis-platinated anthracene precursors. Addition of 5-PYQ to [1-trans-Pt(PEt3)2NO3]-8-chloroanthracene yielded a hybrid MLHB structure with preorganization for a hybrid MLHB polymer. Despite the systems preorganization for the hybrid polymeric structure the assembly of 5-PYQ with 1,8-bis(trans-Pt(PEt3)2NO3)anthracene selects only for one discrete closed self-assembled macrocycle. The strong π-π stacking interactions of the 5-PYQ subunits erode the hydrogen-bonding fidelity to favor ambidentate coordination modes of 5-PYQ and give the non-hybrid macrocycle. In the course of investigating the intricacies of hybrid MLHB supramolecular structures we observed that, in addition to metal-ligand and hydrogen-bond interactions, the π-π stacking interactions of the 7-DPQ and 5-PYQ subunits played a critical role in determining the final assemblies. In fact, the prominent π-π interactions were typically found to be more favorable than the quinolone interligand hydrogen-bonding interactions. These results contribute to the overall knowledge of the design principles, synthesis, characterization, and fundamental assembly trends when exploiting both hydrogen-bonding and metal-ligand interactions to form stable supramolecular architectures. These studies have provided the foundation for expanding the accessible space of supramolecular chemistry to include rationally designed hybrid MLHB systems to give structures that more closely mimic the complex supramolecular systems observed in Nature. This dissertation includes both previously published/unpublished and co-authored material. / 10000-01-01

[pt] Neste trabalho é realizada uma investigação experimental sobre os efeitos de cargas de impacto sobre a resistência de aderência entre o compósito de fibras de carbono e o concreto. O objetivo foi verificar a influência da taxa de carregamento sobre a resistência de aderência. O programa experimental consistiu em ensaios de quarenta e cinco corpos-de-prova, constituídos de blocos de concreto e tiras de fibras de carbono coladas nas laterais opostas dos blocos. As variáveis de estudo foram a resistência à compressão do concreto (25 MPa, 45 MPa e 65 MPa) e a taxa de carregamento que variou de um mínimo de 1,92 MPa/s (estático) para um máximo de 438685 MPa/s (dinâmico). Os resultados dos ensaios mostraram que a resistência de aderência foi afetada pela taxa de carregamento. / [en] An experimental investigation on the effects of impact loading on the bond strength between carbon fiber composite and concrete is described in this work. The objective was to verify the influence of loading rate on the bond strength. The experimental program consisted on testing of forty five specimens made of concrete blocks and carbon fiber strips glued on opposite sides of the block. The variables studied were the concrete compressive strength (25 MPa, 45 MPa and 65 MPa) and loading rate which varied from a minimum of 1,92 MPa/s (static) to a maximum of 438685 MPa/s (dynamic). Test results showed that the bond strength was affected by loading rate.

This thesis presents the application and development of H-bond donor organocatalysts. Chapter 2 presents an intramolecular Michael addition of β-dicarbonyls onto α,β-unsaturated esters catalyzed by tertiary amine/H-bond donor bifunctional catalysts, achieving up to 88% ee. Chapter 3 outlines the design and synthesis of a new family of cinchona-derived H-bond donor/ammonium salt phase-transfer catalysts. The ability of these asymmetric phase-transfer catalysts to activate less reactive substrates than their tertiary amine analogues and to induce higher levels of enantiocontrol than commercially available phase-transfer catalysts was demonstrated in an intramolecular Michael addition. Chapter 4 details the highly successful application of these new H-bond donor/ammonium salt phase-transfer catalysts to the enantio- and diastereoselective nitro-Mannich reaction of α-amido sulfones with nitroalkanes. Preliminary investigations into a novel phase-transfer catalyzed asymmetric ketimine reduction demonstrate the ability of these catalysts to provide access to new methods.

Advanced composite materials are widely used for many structural applications in the aerospace/aircraft industries today. Joining of composite structures using adhesive bonding offers several advantages over traditional fastening methods. However, this technique is not yet employed for fastening the primary structures of aircrafts or space vehicles. There are several reasons for this: There are not any reliable non-destructive evaluation (NDE) methods that can quantify the strength of the bonds, and there are no certifications of quality assurance for inspecting the bond quality. Therefore, there is a significant need for an effective, reliable, easy to use NDE method for the analysis of composite adhesive joints. This research aimed to investigate an adhesively bonded composite-aluminum joints of variable bond strength using digital image correlation (DIC). There are many future possibilities in continuing this research work. As the application of composite materials and adhesive bond are increasing rapidly, the reliability of the composite structures using adhesive bond should quantified. Hence a lot of similar research using various adhesive bonds and materials can be conducted for characterizing the behavior of adhesive bond. The results obtained from this research will set the foundation for the development of ultrasonic DIC as a nondestructive approach for the evaluation of adhesive bond line.

Among primates, humans have the largest and most complex facial repertoires, followed not by their closest living hominid relatives but by hylobatids. Facial behavior is an important component of primate communication that transfers and modulates intentions and motivations. However, why great variation in primate facial expressions evolved and why hylobatid facial repertoires seem to be more similar to humans than other apes is unclear. The current study compared 206 hours of video and 103 hours of focal animal data of facial expression repertoires, measures of pair bond strength, and behavioral synchrony of ten hylobatid pairs from three genera (Nomascus, Hoolock, and Hylobates) living at the Gibbon Conservation Center, Santa Clarita, CA. This study explored whether facial repertoire breath or frequency were linked to social parameters of pair-bonds, how facial expressions related to behavioral synchrony, and if facial feedback (i.e., the transfer of behaviors and intentions by mimicking observed facial expressions) were important between pair-partners. Intra-pair facial repertoires correlated strongly with repertoire composition and rate of use, suggesting that facial feedback was important, while behavioral synchrony showed no correlation with facial behavior. The results of this study suggest that larger facial repertoires contribute to strengthening pair bonds, because richer facial repertoires provide more opportunities for facial feedback which effectively creates a better ‘understanding’ between partners through smoother and better coordinated interaction patterns.

This dissertation details the use of click chemistry to prepare linear and nonlinear polymers containing metal-metal bonds. The incorporation of metal-metal bonds into the polymer simplfies the degradation mechanism, allowing fundamental mechanistic studies of polymer degradation. Click chemistry offered a brand new route to explore the preparation of these useful but intricate metal-metal bond-containing polymers. Chapter I discusses the utility of these types of polymers for mechanistic studies, the preparation of metal dimers with reactive functionalities, and the previous polymerization methods which have been explored. The need for a new polymerization strategy, such as click chemistry, is described. Chapter II explains the preparation of a new metal dimer click synthon, [(η5-C5H4(CH2)3OC(O)(CH2)2C≡CH)Mo(CO)3]2, and the necessary conditions needed to polymerize the synthon using click chemistry. A high molecular weight linear polymer was prepared, suggesting click chemistry is a viable route to nonlinear polymers. Chapter III presents a second novel metal dimer click synthon, [(η5-C5H4(CH2)3N3Mo(CO)3]2, and attempts to use click chemistry to prepare a star polymer containing metal-metal bonds. A small amount of nonlinear polymer was prepared but several reactivity problems were also discovered and addressed. Due to these problems with click chemistry, Chapter IV details a brand new method for preparing asymmetric metal dimers. CpMo(CO)3-Mo(CO)3Cp(CH2)3CH=CH2 is the first reported example of an asymmetric dimer, and (CH3)3CSi(CH3)2O(CH2)3CpMo(CO)3-Mo(CO)3Cp(CH2)3OC(CH3)2OCH3 is the first example of a bifunctional asymmetric dimer. Chapter V describes the synthesis of a different type of metal dimer, (CH3)2Si[(C5H5)Mo(CO)3]2, which is polymerized by thermal ring opening polymerization. The dimer did not polymerize as expected and yielded an interesting polymer which has both Mo-Mo single bonds and Mo≡Mo triple bonds. Finally, Chapter VI provides a summary of the work as well as an honest perspective of using click chemistry to prepare metal-metal bond-containing polymers. This dissertation includes previously published and unpublished co-authored material. / 10000-01-01

In the first chapter of my master's thesis, I consider the life and works of Edward Bond. However, rather than approach this topic from a purely chronological perspective, I consider Bond's unique artistic activity and place it in its critical and historical context. My research emphasizes the significance of Bond's artistic activity in the successful fight against censorship in British theatre. My second chapter explores the idea of 'cool drama.' In this section I utilize commentary from preeminent dramatists in the 1990s who spoke about Bond's pervading cultural influence. I also outline my own views on 'brutal drama' and consider its influence. The third chapter of my work focuses on Bond's 1973 drama 'The Sea,' including the origins of the text, its historical context, and the main dramatic problems of the work. Here I also delve into a summary and analysis of the text, not only from a historical perspective, but also according to my own interpretive analysis. This chapter further contains a cataloging of international productions of 'The Sea', as well as original theoretical analysis of two performances produced in the Czech Republic. I examine and contrast these two productions from the perspective of direction, space, and costume design. In chapter four, I present the practical part of my work while laying out and defending the intellectual and creative concepts behind it. This chapter is divided into several sections. In section A, I present my key interpretive themes, meticulously analyzing the issues and illuminating the way in which they are reflected in my work. I also present the historical background and analysis of my main ideas. I continue in chapter four with a presentation of the sources that were essential influences for the visual elements of my work. I follow with a detailed description of how these sources served as particular artistic solutions in my creative process. I closely analyze their particular dramatic characters, their development and their interactions. I describe the costumes and carefully outline their concrete qualities, such as their materials, colors, silhouettes, movement, and historical elements, all of which are supported with visual attachments. Following this, I consider the search for space of dramatic quality, as well as the overall perception and treatment of particular scenes. I explain each dramatic situation and support it with photographs. The introduction and conclusion contain the opening and final thesis, and I provide an overarching reflection of the work's quality and importance. I conclude the work with a message of gratitude to those who supported me during this project, as well as a list of my research sources.

O objetivo do presente estudo foi avaliar, ex vivo, a influência da irradiação do laser Er,Cr:YSGG na resistência de união do material obturador à base de resina epóxica à dentina radicular, por meio do teste de push-out, e na interface dentina/material obturador, por meio de microscopia confocal a laser. Avaliou-se, ainda, a variação de temperatura externa da dentina radicular durante irradiação. Para tanto, 96 caninos foram instrumentados com sistema rotatório K3 até #45/.02 e irrigados com 2 mL de água destilada e deionizada entre os instrumentos utilizados. Os espécimes foram distribuídos em 3 grupos (n=32) em função do protocolo de irrigação final (10 mL): água destilada e deionizada, NaOCl 1% e EDTAC 17%. Em seguida, foram redistribuídos em 4 subgrupos (n=8), de acordo com a irradiação do laser: não irradiado, 2 W/20 Hz, 3 W/20 Hz e 4 W/20 Hz. Durante a irradiação, foram aferidos os valores máximo e mínimo de temperatura na parede radicular externa nos terços cervical, médio e apical e no ápice radicular. Após irradiação, os espécimes foram obturados com cimento AH Plus e guta-percha pela técnica de condensação lateral. Decorridos três vezes o tempo de endurecimento o tempo de do cimento, as raízes foram seccionadas transversalmente em slices de 1 mm de espessura. Dois slices de cada terço foram submetidos ao push-out em máquina universal de ensaios e o tipo de falha foi analisado em lupa estereoscópica e classificado em: adesiva ao material obturador, adesiva à dentina, mista, coesiva no material obturador e coesiva na dentina. O slice restante foi submetido à análise em microscopia confocal a laser, onde avaliou-se a porcentagem de perímetro da secção transversal do canal radicular com tags de cimento e a profundidade dos tags na interface dentina/material obturador de forma quali-quantitativa. Os dados de resistência de união (Mpa) e porcentagem de perímetro com tags foram analisados por meio do teste ANOVA; enquanto os dados da variação de temperatura (ºC) e profundidade dos tags (&mu;m) por meio do teste de Kruskal-Wallis, ambos seguidos de teste de Tukey. A irradiação do laser Er,Cr:YSGG aumentou a resistência de união do cimento obturador à dentina, independente da irrigação final, sendo que os maiores valores foram obtidos para as potência de 3 W (4,02±1,32) e 4 W (4,18±0,98) e os menores valores para o grupo não irradiado (2,64±0,58) (p<0,05). A potência de 2 W (3,28±0,91) apresentou valores intermediários. A irrigação final com EDTAC 17% resultou em maiores valores de resistência de união (4,01±1,02) quando comparado à água destilada (3,11±1,09) e ao NaOCl 1% (3,47±1,18) (p<0,05). Em relação aos terços radiculares, o terço cervical (4,01±1,21) apresentou valor de resistência de união estatisticamente maior que o terço apical (3,04±0,89), enquanto o terço médio apresentou valores intermediários (3,54±1,15) (p<0,05). Em todos os grupos foi observado maior percentual de falhas adesivas e mistas. Nos grupos irradiados com 3 W [21,1 (14,1-27,7)] e 4 W [17,8 (11,9-23,7)] foi observado maior profundidade de tags do material obturador quando comparado ao grupo não irradiado [12,9 (9,0-20,0)]; a potência de 2 W promoveu valores intermediários [15,6 (11,7-23,3)] de profundidade de tags. Os maiores percentuais de perímetro com tags foram observados para os grupos irradiados, não havendo diferença estatística entre eles (p>0,05). O aumento da temperatura foi proporcional ao aumento da potência do laser, não excedendo 3 ºC. Concluiu-se que o laser Er,Cr:YSGG promoveu aumento da resistência de união do cimento à base de resina epóxica à dentina radicular, com maior formação de tags em todas as potências estudadas, principalmente quando associado à irrigação final com EDTAC 17%; o aumento da temperatura durante a irradiação não foi considerado elevado a ponto de prejudicar os tecidos adjacentes. / The aim of this study was to evaluate ex vivo the influence of Er,Cr:YSGG laser irradiation on the bond strength of an epoxy resin-based root canal sealer to root dentin, using the push-out test, and on the dentin/filling material interface, using confocal laser microscopy. The temperature variation on the outer root dentin during irradiation was also evaluated. For this purposes, 96 canines were instrumented with K3 rotary system up to the #45/.02 instrument, irrigating with 2 mL of distilled and deionized water at each change of instrument. The specimens were randomly assigned to 3 groups (n=32), according the final irrigation protocol (10 mL): distilled and deionized water, 1% NaOCl and 17% EDTAC. They were next reassigned into 4 subgroups (n=8), according to the laser irradiation parameters: non-irradiated, 2 W/20 Hz, 3 W/20 Hz and 4 W/20 Hz. During irradiation, the maximum and minimum temperatures were measured on the outer root dentin wall in the cervical, middle and apical thirds as well in the root apex. Following irradiation, the canals were filled with lateral condensation of AH Plus sealer and gutta-percha cones. After a period three times longer than the sealers setting time, the roots were sectioned transversally to obtain 1-mm-thick slices. Two slices from each third were subjected to a push-out test in a universal testing machine and the failure mode was analyzed with stereoscopic lens and classified as: adhesive to the filling material, adhesive to dentin, mixed, cohesive in the filling material and cohesive in dentin. The remaining slice was analyzed by confocal laser microscopy to evaluate the percentage of the perimeter of the root canal cross-section with sealer tags. The depth of tags at the dentin/filling material interface was evaluated in a quali-quantitative manner. Bond strength (MPa) data and the percentage of perimeter with tags were analyzed by ANOVA, while temperature variation (ºC) and tag depth (&mu;m) were analyzed by Kruskal-Wallis test, both followed by Tukeys test. The Er,Cr:YSGG laser irradiation increased sealer bond strength to dentin, regardless of the final irrigation protocol. The highest values were obtained for 3 W (4.02±1.32) and 4 W (4.18±0.98) powers and the lowest for the non-irradiated group (2.64±0.58) (p<0.05). The use of 2 W power (3.28±0.91) resulted in intermediate values. Final irrigation with 17% EDTAC provided higher bond strength (4.01±1.02) compared with distilled water (3.11±1.09) and 1% (NaOCl 3.47±1.18) (p<0.05). Regarding the root thirds, the cervical third (4.01±1.21) presented significantly higher bond strength than the apical third (3.04±0.89), while the middle third presented intermediate values (3.54±1.15) (p<0.05). In all groups, there was a greater percentage of adhesive and mixed failures. In the groups irradiated with 3 W [21.1 (14.1-27.7)] and 4 W [17.8 (11.9-23.7)], it was observed a greater depth of filling material tags compared with the non-irradiated group [12.9 (9.0-20.0)]; 2 W power produced intermediate tag depth values [15.6 (11.7-23.3)]. The greatest percentage of canal perimeter with sealer tags was observed in the irradiated groups, with no statistically significant difference among them (p>0.05). The temperature rise was proportional to the increase of laser power, not surpassing 3 °C. It was therefore concluded that Er,Cr:YSGG laser irradiation increased the bond strength of an epoxy resin-based sealer to root dentin, with greater formation of sealer tags when for all tested powers, especially if combined with final irrigation with 17% EDTAC; temperature rise during irradiation was not considered high enough to cause harmful effects to the adjacent tissues.

Made available in DSpace on 2014-06-11T19:27:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-05-14Bitstream added on 2014-06-13T20:36:15Z : No. of bitstreams: 1 jacques_p_me_arafo.pdf: 6578711 bytes, checksum: 7ce3c1075cc06b0164a5b42ddcb9c7d0 (MD5) / A resistência adesiva de um sistema auto-condicionante e um convencional simplificado, Clearfil SE Bond e Single Bond, respectivamente, quando aplicados à dentina superficial tratada com diferentes agentes condicionadores, foi avaliada por meio de ensaios mecânicos de microtração. Superfícies planas de dentina, obtidas removendo-se a superfície oclusal de 30 terceiros molares humanos foram polidas com lixa de granulação 600 antes da aplicação de diferentes agentes condicionadores, SE Primer, ácido fosfórico ou EDTA. O primer acidificado SE Primer foi aplicado sobre a superfície por 20 segundos, seguido de suave secagem com jatos de ar. O ácido fosfórico a 37% foi aplicado por 15 segundos, seguido de lavagem e remoção do excesso de água com papel absorvente e a solução de EDTA 0,5M pH7,2 foi aplicada por 30 segundos, também seguida de lavagem e secagem. Com exceção das superfícies que receberam a aplicação do primer acidificado, as demais foram mantidas úmidas para a posterior aplicação dos sistemas adesivos avaliados. Sobre a superfície coberta pelo sistema adesivo foi construída uma coroa em resina composta Z250 e os dentes foram mantidos em água a 37% por 24h. Após 500 ciclos térmicos em temperaturas de 5o e 55oC, cortes paralelos no sentido mesio-distal e cortes perpendiculares aos primeiros, no sentido vestibulo-lingual, permitiram a obtenção de amostras com área de secção transversal quadrangular de 1,0mm2 em número mínimo de 10 para cada dente. Cada amostra foi colada a um dispositivo especialmente desenvolvido, e este foi acoplado à uma máquina universal de testes operada à velocidade de 0,5mm/min. O lado correspondente à dentina de aproximadamente 50% das superfícies fraturadas após o ensaio mecânico foi analizado em MEV. Os resultados mostraram que o maior valor médio de resistência adesiva foi observado para a associação SE Primer... . / Microtensile bond strength of a self-etching primer and a conventional one-bottle system, Clearfi SE Bond and Single Bond, respectively, bonded to superficial dentin treated with different conditioners was investigated. Flat dentin surfaces obtained by removing the occlusal enamel with a diamond saw were ground with 600-grit SiCs under wet conditions to create the smear layer before the conditioners application. Three different dentin conditioning was performed, SE Primer, phosphoric acid and EDTA. The SE Primer was applied on dentin for 20 seconds followed by slight air-drying. Phosphoric acid (37%) was applied for 15 seconds followed by rinsing. EDTA 0.5M pH7.2 was applied for 30 seconds, also followed by water rinsing. Except for the surfaces that received the SE Primer conditioner, the surfaces were left moist by blot-drying the excess water. The adhesive systems were applied and a 5mm high composite resin (Z250) was built up covering the whole surface. After 24h of storage in water at 37oC the teeth were thermocycled for 500 cycles at preset temperatures of 5o and 55oC. The teeth were sectioned with a diamond saw, perpendicular to the adhesive interface to produce beams with 1.0mm2 of adhesive area. These specimens were then attached to a testing apparatus and a tensile load was applied by a universal machine at a crosshead speed of 0.5mm/min. After the micro-tensile bond test, the dentin side of 50% of the fractured surfaces was examined under a scanning electron microscope. The highest tensile bond strength mean was found for the association of SE Primer and Single Bond, 58.51MPa, followed by the association Clearfil SE Bond and EDTA, 47.81MPa. The remaining associations showed mean tensile bond strength statistically similar, except for the association Single Bond and EDTA, which showed the lowest... (Complete abstract, click electronic address below).