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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
951

Evolução em Cycloramphidae : diversidade e especiação na Mata Atlântica brasileira /

Sá, Fábio Perin de. January 2019 (has links)
Orientador: Célio Fernando Baptista Haddad / Resumo: As forças de seleção natural e sexual atuam sobre os indivíduos e podem os levar ao isolamento reprodutivo. O acúmulo de modificações evolutivas pode levar ao surgimento de novas entidades. Espécie é unidade basal em biologia; assim, com sua exuberante biodiversidade, a Mata Atlântica é uma floresta neotropical fundamental para estudos de processos evolutivos em anfíbios anuros. Reunindo os gêneros Cycloramphus, Thoropa e Zachaenus, a família Cycloramphidae agrupa espécies de anuros saxícolas e terrestres, todas endêmicas da Mata Atlântica brasileira. Pelos seus hábitos especializados de vida e reprodução, os cicloramfídeos formam um grupo atrativo para estudos evolutivos. Na presente tese são apresentados quatro capítulos que abordam três escalas distintas da evolução: a diversificação entre espécies, populações e indivíduos. São abordados: (1) a filogenia molecular multilocus de Cycloramphus-Zachaenus, demonstrando que a evolução da terrestrialidade no clado se correlaciona com o dimorfismo sexual em tamanho; (2) a diversificação fenotípica associada a diversificações genéticas em populações de C. boraceiensis e C. dubius, demonstrando que estas duas espécies-irmãs saxícolas apresentam zona de contato e hibridação; (3) o sistema de acasalamento promíscuo e as relações sociais em C. boraceiensis, demonstrando que tamanho das fêmeas e dos machos e parentesco genético influenciam a formação dos casais; e (4) o sistema de acasalamento poligínico com fidelidade na espécie saxíco... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Natural and sexual selection forces act on individuals and may lead to reproductive isolation. The increase in evolutionary modifications may lead to the emergence of new entities. Species is the basal unity in biology; thus, with its exuberant biodiversity, the Atlantic rainforest is a fundamental Neotropical forest for studies of evolutionary processes in anuran amphibians. Comprising the genera Cycloramphus, Thoropa, and Zachaenus, the family Cycloramphidae gathers saxicolous and terrestrial anuran species, all endemic to the Brazilian Atlantic rainforest. Because of their specialized life and reproductive habits, cycloramphids are an attractive group for evolutionary studies. In the present thesis we show four chapters that address three distinct scales of evolution: the diversification among species, populations, and individuals. We goaled: (1) the multilocus molecular phylogeny of Cycloramphus-Zachaenus, demonstrating that the evolution of terrestriality in the clade is correlated with the sexual size dimorphism; (2) the phenotypic diversification associated with the genetic diversifications in populations of C. boraceiensis and C. dubius, demonstrating that these two saxicolous sister species show a contact zone and hybridization; (3) the promiscuous mating system and the social relations in C. boraceiensis, demonstrating that female and male sizes, and mate relatedness influence pair formation; and (4) the polygynic mating system with fidelity in the saxicolous specie... (Complete abstract click electronic access below) / Doutor
952

Hybridation directe d’une pile à combustible PEM et d’un organe supercapacitif de stockage : étude comparative du vieillissement en cyclage urbain, et gestion optimale de la consommation d’hydrogène / Direct hybridization of a PEM fuel cell and a supercapacitor storage device : Comparative study of aging in urban cycling, and optimal management of hydrogen consumption

Arora, Divyesh 17 September 2019 (has links)
La pile à combustible (FC) est peu adaptée aux variations brusques de puissance rencontrées dans les applications transport. L’hybridation de la pile à un supercondensateur (SC) a alors été étudiée, puisque cet organe de stockage capacitif permet de gérer les transitoires de puissance. L’hybridation est directe/passive, permettant ainsi de réduire le volume, la masse et le coût du système. Initialement, la faisabilité et l’impact de la taille du SC sur la performance de la FC en mono-cellule ont été examinés numériquement. Cette modélisation montre que l’augmentation de la taille du SC renforce l’effet de lissage induit par l’utilisation du SC sur le courant de la FC. Il en résulte des variations lentes et une réduction des amplitudes de courant et de tension, une diminution du courant efficace de la FC, et donc des pertes électriques de celle-ci. L’hybridation de la FC, comparativement à son fonctionnement seule, permet en outre de réduire la surconsommation en H2 de près de 50 % dans les mêmes conditions opératoires. Ces résultats ont été validés par des essais expérimentaux réalisés en mono-cellule et 3-cellules de 100 cm2 hybridée ou non. Par la suite, toujours en utilisant le protocole de cyclage urbain (FC-DLC), la durabilité de la FC a été étudiée lors d’essais de longue durée. La durabilité de la FC, qu’elle soit hybridée ou non, est la même. L’hybridation n’améliore donc pas la durée de vie de la FC mais ne lui nuit pas non plus. Par la suite, afin d’encore réduire la surconsommation en H2 en longue durée cyclage, différentes stratégies ont été étudiées : diminution du débit minimum des gaz imposé par le cyclage et diminution du coefficient de surstœchiométrie en H2. Ces changements n’ont pas d’influence sur la durabilité de la pile hybridée et ont permis de réduire à 10 % la surconsommation en hydrogène. La FC non hybridée, quant à elle, a vu sa durabilité divisée par deux lors de la diminution des débits minimum et ne fonctionnait pas avec le coefficient de surstœchiométrie ramené à 1,1. Ensuite, les travaux ont été étendus à un stack FC de forte puissance (Système Ballard de 1,2 kW) hybridé à deux modules de SC de 165 F (Maxwell Technologies). En final, un système hybride de 34 kW (FC de 10 kW et SC de 566.67 F) a montré des performances suffisantes pour une application transport urbain et péri-urbain. De plus, comparativement à une pile de 34 kW 21 % d’hydrogène sont économisés et l'investissement des équipements peut être réduit de près 50 % / The fuel cell (FC) is poorly adapted to the sudden variations in power encountered in transport applications. The FC hybridization to a supercapacitor (SC) was then studied, since this capacitive storage device allows to manage the power transients. Hybridization is direct/passive, thus reducing the volume, mass and cost of the system. Initially, the feasibility and the impact of SC size on FC performance have been examined numerically. Theoretical investigations show that increasing the size of SC enhances the smoothing effect introduced by the supercapacitor on FC current. This results into slow variations and reduction in both current and voltage amplitudes, a decrease in the fuel cell’s effective current, and therefore in FC electrical losses. Hybridization, compared to its FC operation alone, still reduces hydrogen overconsumption by nearly 50 % under the same operating conditions. These results have been validated by experimental tests carried out on a 100 cm2 single FC and a 3 cell stack. Later, the durability of the FC system has been investigated through long term tests. These durability tests have been conducted on the 100 cm2 single FC test bench using urban cycling protocol (FC-DLC), for both hybridized and unhybridized FC system, with continuous evaluation of degradation extent and causes. These tests suggest no detrimental impact on durability of the FC. For these two operating modes, a progressive aging of the gas diffusion layer seems to appear. Subsequently, in order to further reduce the overconsumption of hydrogen in long-term FC-DLC cycling, different strategies were studied: reducing the minimum gas flow rate imposed by FC-DLC cycling from 0.2 to 0.05 A cm-2, and reducing the hydrogen overstoichiometry coefficient from 1.2 to 1.1. These changes have no influence on the durability of the hybrid cell and have reduced hydrogen overconsumption to 10 %. On the contrary, in case of the unhybridized FC, durability was halved as minimum flows were reduced and it did not work when the overstoichiometry reduced coefficient. Further, work has been extended to high power FC systems (1.2 kW FC system, hybridized with two modules of 165 F, SC module). Finally, the FC downsizing has been demonstrated from 34kW FC system to hybrid source system of 10kW FC hybridized with 566.64 F SC, presenting 21 % hydrogen saving and nearly 50 % net cost savings.
953

Functional colloidal surface assemblies: Classical optics meets template-assisted self-assembly

Gupta, Vaibhav 09 December 2020 (has links)
Abstract: When noble metals particles are synthesized with progressively smaller dimensions, strikingly novel optical properties arise. For nanoscale particles, collective disturbances of the electron density known as localized surface plasmons resonances can arise, and these resonances are utilized in a variety of applications ranging from surface-enhanced molecular spectroscopy and sensing to photothermal cancer therapy to plasmon-driven photochemistry. Central to all of these studies is the plasmon’s remarkable ability to process light, capturing and converting it into intense near fields, heat, and even energetic carriers at the nanoscale. In the past decade, we have witnessed major advances in plasmonics which is directly linked with the much broader field of (colloidal) nanotechnology. These breakthroughs span from plasmon lasing and waveguides, plasmonic photochemistry and solar cells to active plasmonics, plasmonics nanocomposites and semiconductor plasmons. All the above-mentioned phenomena rely on precise spatial placement and distinct control over the dimensions and orientation of the individual plasmonic building blocks within complex one-, two- or three-dimensional complex arrangements. For the nanofabrication of metal nanostructures at surfaces, most often lithographic approaches, e.g. e-beam lithography or ion-beam milling are generally applied, due to their versatility and precision. However, these techniques come along with several drawbacks such as limited scalability, limited resolution, limited compatibility with silicon manufacturing techniques, damping effects due to the polycrystalline nature of the metal nanostructures and low sample throughput. Thus, there is a great demand for alternative approaches for the fabrication of metal nanostructures to overcome the above-mentioned limitations. But why colloids? True three-dimensionality, lower damping, high quality modes due to mono-dispersity, and the absence of grain boundaries make the colloidal assembly an especially competitive method for high quality large-scale fabrication. On top of that, colloids provide a versatile platform in terms of size, shape, composition and surface modification and dispersion media. 540The combination of directed self-assembly and laser interference lithography is a versatile admixture of bottom-up and top-down approaches that represents a compelling alternative to commonly used nanofabrication methods. The objective of this thesis is to focus on large area fabrication of emergent spectroscopic properties with high structural and optical quality via colloidal self-assembly. We focus on synergy between optical and plasmonic effects such as: (i) coupling between localized surface plasmon resonance and Bragg diffraction leading to surface lattice resonance; (ii) strong light matter interaction between guided mode resonance and collective plasmonic chain modes leading to hybrid guided plasmon modes, which can further be used to boost the hot-electron efficiency in a semiconducting material; (iii) similarly, bilayer nanoparticle chains leading to chiro-optical effects. Following this scope, this thesis introduces a real-time tuning of such exclusive plasmonic-photonic (hybrid) modes via flexible template fabrication. Mechanical stimuli such as tensile strain facilitate the dynamic tuning of surface lattice resonance and chiro-optical effects respectively. This expands the scope to curb the rigidity in optical systems and ease the integration of such systems with flexible electronics or circuits.:Contents Abstract Kurzfassung Abbreviations 1. Introduction and scope of the thesis 1.1. Introduction 1.1.1. Classical optics concepts 1.1.2. Top down fabrication methods and their challenges 1.1.3. Template-assisted self-assembly 1.1.4. Functional colloidal surface assemblies 1.2. Scope of the thesis 2. Results and Discussion 2.1. Mechanotunable Surface Lattice Resonances in the Visible Optical Range by Soft Lithography Templates and Directed Self-Assembly 2.1.1. Fabrication of flexible 2D plasmonic lattice 2.1.2. Investigation of the influence of particle size distribution on SLR quality 2.1.3. Band diagram analysis of 2D plasmonic lattice 2.1.4. Strain induced tuning of SLR 2.1.5. SEM and force transfer analysis in 2D plasmonic lattice under various strain 2.2. Hybridized Guided-Mode Resonances via Colloidal Plasmonic Self-Assembled Grating 2.2.1. Fabrication of hybrid opto-plasmonic structure via template assisted self-assembly 2.2.2. Comparison of optical band diagram of three (plasmonic, photonic and hybrid) different structures in TE and TM modes 2.2.3. Simulative comparison of optical properties of hybrid opto-plasmonic NP chains with a grating of metallic gold bars 2.2.4. Effect of cover index variation with water as a cover medium 2.3. Hot electron generation via guided hybrid modes 2.3.1. Fabrication of the hybrid GMR structure via LIL and lift-off process 2.3.2. Spectroscopic and simulative analysis of hybrid opto-plasmonic structures of different periodicities 2.3.3. Comparative study of photocurrent generation in different plasmonic structures 2.3.4. Polarization dependent response at higher wavelength 2.3.5. Directed self-assembly of gold nanoparticles within grating channels of a dielectric GMR structure supported by titanium dioxide film 2.4. Active Chiral Plasmonics Based on Geometrical Reconfiguration 2.4.1. Chiral 3D assemblies by macroscopic stacking of achiral chain substrates 3. Conclusion 4. Zusammenfassung 5. Bibliography 6. Appendix 6.1. laser interference lithography 6.2. Soft molding 6.3. Determine fill factor of plasmonic lattice 6.4. 2D plasmonic lattice of Au_BSA under strain 6.5. Characterizing order inside a 2D lattice 6.6. Template-assisted colloidal self-assembly 6.7. Out of plane lattice resonance in 1D and 2D lattices 6.8. E-Field distribution at out of plane SLR mode for 1D lattices of various periodicity with AOI 20° 6.9. Refractive index of PDMS and UV-PDMS 6.10. Refractive index measurement for sensing 6.11. Optical constants of TiO2, ma-N 405 photoresist and glass substrate measured from spectroscopic ellipsometry Acknowledgement/ Danksagung Erklärung & Versicherung List of Publications
954

Deconstructing the “Low Other” in the First Wave of Sex Hygiene Films (1914-1919)

Cârstian, Maria January 2019 (has links)
The present thesis investigates the commercial sex hygiene films produced between the years 1914 and 1919 in the United States, during the last years of the Progressive Era. Rejected and prohibited as soon as five years after their apparition, the sex hygiene films’ position within the industry, as well as the cinematic techniques they incorporated, will be analysed through the concept of the Low Other. The first part of the thesis aims to delineate the used concepts, as well as integrate the sex hygiene film into a wider cultural, social, and political framework. The second part explores the films’ aesthetic construction, then focuses on a textual analysis of the narrative and non-narrative methods implied by three particular sex hygiene films. Finally, the thesis concludes that the films used a series of cinematic methods to create a Low Other on-screen, yet these very methods ultimately played a part within their suppression as a Low Other body of culture.
955

Kibbi and kinship: Lebanese home cooking in Latin America as a method for memory, kinship, and the hybridization of food and identity

Lord, Giselle Kennedy January 2018 (has links)
CHAPTER I: INTRODUCTION The purpose of this study is to explore the practice, significance, and development over time of ‘traditional’ home cooking for the descendants of Lebanese immigrants in Argentina and greater Latin America. This is an exploratory paper suggestive of themes that could be examined more deeply through more localized research (Rowe 2012). Nonetheless, this study supports a number of conclusions about this dynamic diasporic group and its relationship to traditional food practices. Narratives and responses about meaning in memory, kinship, and tradition tell an important story about motivations for engaging in food and cooking practices among the descendants of the Lebanese diaspora in Latin America. My study shows that my participants and respondents engage in food and cooking practice as a largely unselfconscious reproduction of cultural identity motivated primarily by a desire to connect with their kin, to evoke memories of their past, and to preserve the gastronomic heritage taught to them—whether directly or indirectly—by their immigrant ancestors. [TRUNCATED]
956

Studium probiotických bakterií mléčného kvašení produkujících antimikrobiální látky / Study of Probiotic Lactic Acid Bacteria Producing Antimicrobial Compounds

Turková, Kristýna January 2014 (has links)
The sixty-eight strains isolated from breastfed full-term infant feces and from another sources were identified using genus-specific polymerase chain reaction (PCR) for Lactobacillus, species-specific PCRs, multiplex PCR, pheS PCR, rep-PCR, RAPD-PCR and 16S rDNA sequencing into Lactobacillus species or group of species. Seven strains produced antimicrobial proteinaceous substances in the supernatants. Antimicrobial proteinaceous substances of three strains were tested on temperature, pH a detergent stability. All tested strains produced temperature-stable antimicrobial proteinaceous substances. Antimicrobial activity was not influenced by detergents with exception of SDS. Presence of genes for production of bacteriocins (acidocin B, gassericin A, gassericin T, gassericin K7A and gassericin K7B) were detected in DNA of fourteen strains using PCR and DNA/DNA hybridization. Selected PCR products were sequenced and analyzed using BLAST algorithm and CLUSTAL W2 programme. The sequences of specific PCR products in DNA of two strains had 100% similarity with the sequences from the database GeneBank. Selected strains of Lactobacillus acidophilus group were tested for the surveillance in gastrointestinal tract, for the production of antimicrobial substances, for the adhesion on Caco-2 cells and for the presence of genes of antibiotic resistance. DNA of strains was tested using specific primers on the presence of genes for histidine-decarboxylase, tyrosine-decyrboxylase and linoleate isomerase. The gene for histidine-decarboxylase production was detected in DNA of seven strains, for tyrosine-decarboxylase production in DNA of one strain and for linoleate isomerase in DNA of four strains. Imunomagnetic separation of the cells was optimized. Magnetic particles functionalized with streptavidin and the anti-Lactobacillus antidote was used for the separation of the cells of Lactobacillus rhamnosus LOCK 0900 from MRS medium, UHT milk and from the yogurt. The IMS-PCR was used for detection of imunomagnetic separated bacterial cells.
957

Riziko hybridizace ohrožené třešně křovité (Prunus fruticosa) s pěstovanými zástupci rodu Prunus / Assessing the threat of hybridization between Prunus fruticosa and cultivated Prunus species

Musilová, Lenka January 2013 (has links)
Presented thesis evaluates the risk of ongoing hybridization (antropohybridization) in highly endangered Prunus fruticosa in the Czech Republic and selected adjacent countries. Absolute genome size analysis (estimated by flow cytometry) combined with both numeric and geometric morphometrics were used for evaluation of hybridization. Prunus fruticosa frequently hybridize with naturalized Prunus cerasus (emerging tetraploid hybrid Prunus ×eminens) and native Prunus avium (forming triploid hybrid Prunus ×mohacsyana). Discrimination between P. ×eminens and P. ×mohacsyana is difficult, when using leaf morphology characters only, so the occurrence of triploid hybrids was strongly underestimated in the Czech Republic (only tetraploid hybrids were reported). Both hybrids are surely differentiated using flow cytometry analysis (based on different ploidy level). The majority of analyzed populations is formed by either individuals of pure P. fruticosa or one of the mentioned hybrids. Only four populations were mixed. Continuous variability in absolute genome size was found in two of them, which may indicate hybrid swarm forming (incl. primary hybrids and backcrosses). Our findings can be considered only as indirect evidence for introgression, which needs to be confirmed by molecular markers (for example...
958

Experimentální studium reprodukčních způsobů komplexu Arabidopsis arenosa / Experimental studies of reproduction in Arabidopsis arenosa complex

Vlčková, Veronika January 2016 (has links)
No description available.
959

Mapování rozšíření kříženců jelenů evropských a jelenů sika v ČR s využitím občanské vědy a audionahrávek / Mapping of distribution of red deer and sika deer hybrids in Czechia using audio recordings - citizen science project

Nečasová, Monika January 2020 (has links)
In the Czech Republic, as in other parts of Europe (e.g., British Isles), the native European red deer (Cervus elaphus) has been hybridising with sika deer (C. nippon), which was introduced from East Asia. The hybrids are fertile, and, therefore, can backcross with their parental species and threaten their genetic integrity. Offsprings of such multiple crosses are very difficult to identify according to their morphological traits, while more reliable genetic methods are financially and logistically demanding. This work follows the study of Long et al. from 1998, which showed clear differences in vocalization between red deer, sika deer and the first generation of their hybrids, and thus suggested the third way how to identify hybrids - bioacoustic analysis. We decided to test this method in the Czech Republic in a citizen science project, the aim of which was to map the distribution of parent species and their hybrids using audiorecordings of rut vocalisation. To allow more detailed analysis, we also recorded our own recordings on a professional recording device with a directional microphone. In total, 451 recordings were collected, of which only 263 with a vocalization of 162 individuals were selected for further analysis. Recordings from previous studies from Ireland (Long et al. 1998; Wyman et...
960

Strategie založení sociálního podniku nestátní neziskovou organizací / Strategies that non-profit organizations can use for the establishment of a social enterprise

Bernášková, Kristýna January 2016 (has links)
The Diploma thesis deals with the possible strategies that non-profit organizations can use for the establishment of a social enterprise. These strategies were designed on various relationship models non-profit and social enterprise can have. These models are different in the extent to which social enterprises and non-profit organizations share social and economic activities. These models and also possible motivations of non-profit organizations, which lead to the establishment of a social enterprise are described in the theoretical section. In the practical part, these models are applied to the decision-making process of non-profit organization Life 90, z. ú., which is planning to establish a social enterprise. is evaluated considering its pros and cons from the point of view of non-profit organisations.. These findings and each model and its applicability for Czech non-profit organizations were evaluated as a result of my thesis. KEY WORDS Social entrepreneurship, non-profit organizations, NGOs, commercialization, hybridization, case study, EMES International Research Network

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