No description available.

No description available.

Ce manuscrit présente la synthèse et la caractérisation de deux nouvelles familles de complexes mononucléaires, [Fe(L)2(NCS)2] et [Fe(L)(H2B(pz)2)2], montrant des propriétés bistables. L’étude des structures cristallographiques a permis de discuter l’influence de l’élongation des ligands L sur le réseau cristallin et sur les contacts intermoléculaires ainsi que l’existence de corrélations structures / propriétés. Enfin, la dernière partie de ce travail est consacrée à l’élaboration de façon contrôlée d’objets à transition de spin à l’échelle nanométrique, sous la forme de films déposés par sublimation et de nanoclusters synthétisés en milieu confiné. / This thesis presents the synthesis and characterization of two new families of mononuclear complexes, [Fe(L)2(NCS)2] and [Fe(L)(H2B(pz)2)2] showing bistable properties. The crystallographic studies allowed us to discuss the influence of the elongation of the ligands L on the crystal lattice, intermolecular contacts and the existence of structure / properties correlations. The final part of this work shows the controlled synthesis of spin crossover objects at the nanometric scale as thin films prepared by sublimation and nanoclusters synthesized in confined media.

SANTOS, T. B. dos. Transições de fase de não equilíbrio em redes de Kleinberg. 2017. 80 f. Tese (Doutorado em Física) – Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2017. / Submitted by Giordana Silva (giordana.nascimento@gmail.com) on 2017-04-03T21:15:03Z No. of bitstreams: 1 2017_tese_tbdsantos.pdf: 2830575 bytes, checksum: 39857a136c65b792df574b172c4dbb8f (MD5) / Approved for entry into archive by Giordana Silva (giordana.nascimento@gmail.com) on 2017-04-03T21:33:08Z (GMT) No. of bitstreams: 1 2017_tese_tbdsantos.pdf: 2830575 bytes, checksum: 39857a136c65b792df574b172c4dbb8f (MD5) / Made available in DSpace on 2017-04-03T21:33:08Z (GMT). No. of bitstreams: 1 2017_tese_tbdsantos.pdf: 2830575 bytes, checksum: 39857a136c65b792df574b172c4dbb8f (MD5) Previous issue date: 2017 / We study through Monte Carlo simulations and finite-size scaling analysis the nonequilibrium phase transitions of the majority-vote model and the contact process taking place on spatially embedded networks. These structures are built from an underlying regular lattice over which long-range connections are randomly added according to the probability, Pij ~ rα , where rij is the Manhattan distance between nodes i and j, and the exponent α is a controlling parameter [J. M. Kleinberg, Nature 406, 845 (2000)]. Our results show that the collective behavior of those systems exhibits a continuous phase transition, order-disorder for the majority-vote model and active-absorbing for the contact process, at a critical parameter, which is a monotonous function of the exponent α. The critical behavior of the models has a non-trivial dependence on the exponent α. Precisely, considering the scaling functions and the critical exponents calculated, we conclude that the systems undergoes a crossover between distinct universality classes. For α ≤ 3 the critical behavior in both systems is described by mean-field exponents, while for α ≥ 4 it belongs to the 2D Ising universality class for majority-vote model and to Directed Percolation universality class for contact process. Finally, in the region where the crossover occurs, 3< α <4, the critical exponents vary continuously with the exponent α. We revisit the symbiotic contact process considering a proper method to generate the quasistatiorary state. We perform Monte Carlo simulations on complete and random graphs that are in accordance with the mean-field solutions. Moreover, it is observed hysteresis cycles between the absorbing and active phases with the presence of bistable regions. For regular square lattice, we show that bistability and hysteretic behavior are absence, implying that model undergone a continuous phase transition for any value of the parameter that controlled the symbiotic interaction. Finally, we conjecture that the phase transition undergone by the symbiotic contact process will be continuous or discontinuous if the topology considered is below or above of the upper critical dimension, respectively. / Estudamos por meio de simulações de Monte Carlo e análises de escala de tamanho finito as transições de fase que os modelos do votante majoritário e do processo de contato descrevem em redes de Kleinberg. Tais estruturas são construídas a partir de uma rede regular onde conexões de longo alcance são adicionadas aleatoriamente seguindo a probabilidade Pij ~ rα, sendo rij a distância Manhattan entre dois nós i e j e o expoente α um parâmetro de controle [J. M. Kleinberg, Nature 406, 845 (2000)]. Nossos resultados mostram que o comportamento coletivo desses sistemas exibe uma transição de fase contínua, do tipo ordem-desordem para o votante majoritário e ativo absorvente para o processo de contato, no parâmetro crítico correspondente. Tal parâmetro é monotônico com o expoente α, sendo crescente para o votante majoritário e decrescente para o processo de contato. O comportamento crítico dos modelos apresenta uma dependência não trivial com o expoente α. Precisamente, considerando as funções de escala e os expoentes críticos, concluímos que os sistemas passam pelo fenômeno de crossover entre duas classes de universalidade. Para α ≤ 3, o comportamento crítico é descrito pelos expoentes de campo médio enquanto que para α ≥ 4 os expoentes pertencem à classe de universalidade de Ising 2D, para o modelo do votante majoritário, e à classe da percolação direcionada no caso do processode contato. Finalmente, na região 3< α <4 os expoentes críticos variam continuamente com o parâmetro α. Revisamos o processo de contato simbiótico aplicando um método alternativo para gerarmos estados quase estacionários. Desta forma, realizamos simulações de Monte Carlo em grafos completos, aleatórios, redes espacialmente incorporadas e em redes regulares. Observamos que os resultados para o grafo completo e redes aleatórias concordam com as soluções das equações de campo médio, com a presença de ciclos de histerese e biestabilidade entre as fases ativa e absorvente. Para redes regulares, comprovamos a ausência de biestabilidade e comportamento histerético, implicando em uma transição de fase contínua para qualquer valor do parâmetro que controla a interação simbiótica. E por fim, conjecturamos que a transição de fase descrita pelo processo de contato simbiótico será contínua ou descontínua se a topologia de interesse estiver abaixo ou acima da dimensão crítica superior, respectivamente.

During meiosis eukaryotes produce four haploid gametes from a single diploid parental cell. In meiotic S-phase homologous chromosomes, which were inherited from maternal and paternal parents, are replicated. Homologous chromosomes then pair and undergo reciprocal crossover, which generates new mosaics of maternal and paternal sequences. Meiosis also involves two rounds of chromosome segregation, meaning that only one copy of each chromosome is finally packaged into the resulting haploid gametes. In this work I sought to genetically engineer two elements of meiosis, in order to generate tools which may be useful for plant breeding. The first project sought to generate a second division restitution (SDR) population, where the second meiotic division is skipped. This is created by crossing an SDR mutant, omission of second division1, which produces diploid pollen due to a defective meiosis-II, to a haploid inducer line, whose chromosomes are lost from the zygote post-fertilisation. This was intended to give rise to diploid plants possessing chromosomes from just the SDR parent. Importantly, the SDR parent used was heterozygous, meaning that SDR progeny should show mostly homozygous chromosomes, but with regions of residual heterozygosity, determined by crossover locations. This project succeeded in creating a small number of plants with the predicted SDR genotype, although a range of aberrant genotypes were also observed. I present several hypotheses that could account for the observed progeny genotypes. In a second project I attempted to direct meiotic recombination using DNA double strand breaks targeted to specific sites. This project used a spo11-1 mutant, which is unable to produce the endogenous meiotic DNA DSBs that normally mature into crossovers. Instead, TALFokI nucleases (TALENs) were expressed from meiotic promoters in order to generate exogenous DSBs at sites determined by the DNA binding specificity of the TAL repeat domains. The project succeeded in transforming TALENs into spo11-1 mutants and confirming their expression. However, this was not sufficient to recover the spo11-1 mutant infertility or direct crossovers. Potential reasons for this non-complementation are discussed, as well as their implications for control of meiotic recombination in plant genomes.

abstract: This dissertation proposes a new set of analytical methods for high dimensional physiological sensors. The methodologies developed in this work were motivated by problems in learning science, but also apply to numerous disciplines where high dimensional signals are present. In the education field, more data is now available from traditional sources and there is an important need for analytical methods to translate this data into improved learning. Affecting Computing which is the study of new techniques that develop systems to recognize and model human emotions is integrating different physiological signals such as electroencephalogram (EEG) and electromyogram (EMG) to detect and model emotions which later can be used to improve these learning systems. The first contribution proposes an event-crossover (ECO) methodology to analyze performance in learning environments. The methodology is relevant to studies where it is desired to evaluate the relationships between sentinel events in a learning environment and a physiological measurement which is provided in real time. The second contribution introduces analytical methods to study relationships between multi-dimensional physiological signals and sentinel events in a learning environment. The methodology proposed learns physiological patterns in the form of node activations near time of events using different statistical techniques. The third contribution addresses the challenge of performance prediction from physiological signals. Features from the sensors which could be computed early in the learning activity were developed for input to a machine learning model. The objective is to predict success or failure of the student in the learning environment early in the activity. EEG was used as the physiological signal to train a pattern recognition algorithm in order to derive meta affective states. The last contribution introduced a methodology to predict a learner's performance using Bayes Belief Networks (BBNs). Posterior probabilities of latent nodes were used as inputs to a predictive model in real-time as evidence was accumulated in the BBN. The methodology was applied to data streams from a video game and from a Damage Control Simulator which were used to predict and quantify performance. The proposed methods provide cognitive scientists with new tools to analyze subjects in learning environments. / Dissertation/Thesis / Doctoral Dissertation Industrial Engineering 2017

The use of two different chelating redox active ligands, 2,6-bis(6-methyl-1,2,4,5-3-yl) pyridine (BTZP) and 2,6-bis-(5,6-dialkyl-1,2,4-triazin-3-yl)-pyridine (BTP) in heterometallic first row and second row transition metal chemistry has yielded two new families of redox active metal complexes. These complexes were found to exhibit interesting electrochemical and magnetic properties. In this thesis, Chapter 1 lays the foundation for the research presented within. This section covers the fundamentals of the ligand design, ligand synthesis and related coordination chemistry literature review. Chapters 2 and 3 report the results of the current thesis. In Chapter 2, the synthesis and characterization of a family of discrete molecules and supramolecular arrangements, employing the ligand BTZP, is presented. All of the complexes presented in Chapter 2 are successfully synthesized and characterized with electrochemical and magnetic studies. According to the electrochemical data, it is found that the classic “terpy-like” complexes with [Co(BTZP) 2]2+ formula fosters more stability in the redox process. In Chapter 3, a family of transition metal complexes with [M(BTP) 2]2+ (M=Fe or Co) inorganic cores were obtained through the employment of the ligand BTP with various anions. In addition, dimeric molecules with [CoX4(BTP)2] formula were also obtained by solvothermal synthesis. The complexes were also electrochemically characterized, with all the complexes capable of being reduced, while only [CoII(BTP)2] (ClO4)2 showed reversible redox process. Similar with BTZP, the series of BTP based complexes are also characterized through magnetic measurement. Only cobalt-based BTP complexes are paramagnetic, with [CoII(BTP)2]2+ being spin crossover active when BF4- and ClO4- are present. However, the presence of NCS- and halides lead to either antiferromagnetic interactions and ferromagnetic interactions dominating at different temperature regimes.

Les polymères de coordination fer-triazole constitue une famille des composés à transition de spin particulièrement étudiée au cours des deux dernières décennies en raison de la présence du caractère hystérétique et abrupt de leur transition de spin. Leur mise en forme et la conservation de leurs propriétés reste cependant une problématique d’actualité. L’objectif de cette thèse est de répondre à cette problématique en synthétisant un métallogel renforcé par des nanoparticules de silice, aboutissant à un nanocomposite hybride à transition de spin. Cet objectif fut rempli grâce à un balayage des paramètres physico-chimiques du système et un contrôle rigoureux des conditions expérimentales. Le gel obtenu a été caractérisé par de multiples techniques, ce qui a permis de proposer des mécanismes d’action des différentes composantes du système sur ses propriétés de transition de spin. Afin d’améliorer ses propriétés mécaniques, une matrice de silice hybride a été synthétiser in situ dans l’échantillon par voie sol-gel en phase vapeur. Le matériau obtenu est fonctionnel et manipulable, et a été ensuite caractérisé en détail afin de conclure sur l’influence de ce traitement sur les propriétés de transition de spin du composite. Enfin, une approche « bottom-up » du système polymère fer-triazole - triazole a été étudiée, avec comme objectifs la synthèse d’un précurseur alcoxysilane fonctionnalisé par un triazole et « l’habillage » de nanoparticules de silice par le polymère afin d’étudier leur auto-assemblage. / Iron-triazole coordination polymers have been extensively studied during the last two decades as a class of spin crossover compounds because of their hysteretic and abrupt spin crossover properties. Their use has been limited due to the difficulty to integrate them into a functional material which is still a challenge today. The main goal of this PhD. project is to address this issue by designing a metallogel reinforced by the adjunction of silica nanoparticles, allowing us to prepare a hybrid spin crossover nanocomposite. We achieved this aim by screening the physicochemical parameters of the system and carefully tuning of the experimental conditions. The resulting gel has been extensively characterized by different technics, allowing us to make assumptions for the role of each component of the system on its spin crossover properties. We improved its mechanical properties by in situ chemical vapour deposition of silica, forming a hybrid matrix by sol gel process. The resulting material is functional and easy to handle, and has been further characterized to conclude on the influence of this process on the composite spin crossover properties. Finally, a “bottom-up” approach of the iron-triazole polymer – silica system has been studied, with the aim of a triazole functionalized alcoxysilane precursor and the preparation of polymer wrapped silica nanoparticles in order to study their auto-assembling properties.

La spintronique multifonctionnelle est une nouvelle direction d'avancement pour aller au-delà des limites de l'électronique moderne. Il vise à développer des dispositifs qui seraient sensibles à plus d’un stimulus et/ou ont un signal multi-réponse. Dans cette thèse, nous explorons cette voie multifonctionnelle émergente en combinant l’électronique de spin et les systèmes organiques pour ouvrir la voie vers des dispositifs polyvalents. Nous étudions la formation d'une spinterface dans le système Co/manganèse-phthalocyanine. Nous proposons l'introduction de multifonctionnalités intrinsèques en utilisant des matériaux à transition de spin. Nous développons une nouvelle approche de fonctionnalisation pour ajuster leurs propriétés vers des applications. Nous proposons un contrôle fonctionnel externe sur une spinterface en utilisant un substrat multiferroïque. Dans le cadre de cette thèse, un insert polyvalent à température variable a été développé à la ligne de lumière DEIMOS du synchrotron SOLEIL. Nous démontrons comment il peut être utilisé pour sonder des atomes actifs dans n'importe quel dispositif électronique. / Multifunctional spintronics is a new direction of advancement beyond the limits of modern electronics. By combining elementary charge of an electron and its spin, it aims to develop devices which would be sensitive to more than one stimuli and/or have multiresponse signal. In this thesis, we explore the multifunctional potential emerging while combining spin electronic and organic systems to pave the way towards multipurpose devices. First, we study formation of a ferromagnetic/organic spinterface in Co/manganese-phthalocyanine system. We propose introduction of intrinsic multifunctionality by using spin crossover materials. We develop a novel functionalization approach for tuning their properties towards device applications. We propose an external functional control over any hybrid spinterface by using multiferroic substrate. In the framework of this thesis, a Versatile Variable Temperature Insert was developed at the DEIMOS beamline of the SOLEIL synchrotron. We demonstrate how it can be used to probe active atoms in any microelectronic device.

This thesis aims to see how individual and partner’s unemployment affect self-rated depressive symptoms, both for individuals separately, and for individuals in a relationship within Europe. The research questions were examined by using European Social Survey (ESS) data from 2014. An index was created in order to capture the phenomena of depressive symptoms. To investigate the effect of unemployment in relation to self-rated depression, multiple regressions analysis were used. The results show that there is a relationship between unemployment and depressive symptoms, for both men and women. However, men tend to be affected by their own unemployment only, whereas evidence was found supporting that having an unemployed partner affect depressive symptoms in a negative way for women. Hence, women are a more vulnerable group on the labour market, because they are not only affected by their own labour market status, but also by the labour market status of their partners.