908 resultados para Complex dynamics


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Los procesos de integración latinoamericana vienen siendo estudiados desde hace tiempo, y su abordaje plantea múltiples dimensiones para la investigación social. En el presente trabajo se indagan algunas de las características de la territorialidad en la región suramericana para preguntarse por algunos de los procesos de integración que atañen a Suramérica, particularmente respecto del bloque UNASUR, poniendo especial énfasis en las transformaciones que han operado en las últimas décadas. El enfoque territorial será la lupa a través de la cual se intentará tener un primer acercamiento al fenómeno atravesado por dinámicas de poder más amplias y más complejas. Se comienza con una reflexión inicial en torno a los modos de concebir analíticamente el territorio, que está invadido por múltiples lógicas y mecanismos de poder. El recorrido por los debates sobre las modalidades de inserción internacional, así como por las etapas de regionalismo en Latinoamérica, contribuirá a la descripción de las nuevas condiciones que se dan en la región a la hora de analizar el surgimiento de nuevos bloques de poder. Así, podremos preguntarnos si el bloque de Unasur es estructurado sobre nuevas lógicas de construcción de poder. Su estudio permitirá también indagar en los desafíos que su conformación plantea y en las tensiones y en los conflictos de intereses que los distintos propósitos de integración que conviven en Unasur conllevan

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Los procesos de integración latinoamericana vienen siendo estudiados desde hace tiempo, y su abordaje plantea múltiples dimensiones para la investigación social. En el presente trabajo se indagan algunas de las características de la territorialidad en la región suramericana para preguntarse por algunos de los procesos de integración que atañen a Suramérica, particularmente respecto del bloque UNASUR, poniendo especial énfasis en las transformaciones que han operado en las últimas décadas. El enfoque territorial será la lupa a través de la cual se intentará tener un primer acercamiento al fenómeno atravesado por dinámicas de poder más amplias y más complejas. Se comienza con una reflexión inicial en torno a los modos de concebir analíticamente el territorio, que está invadido por múltiples lógicas y mecanismos de poder. El recorrido por los debates sobre las modalidades de inserción internacional, así como por las etapas de regionalismo en Latinoamérica, contribuirá a la descripción de las nuevas condiciones que se dan en la región a la hora de analizar el surgimiento de nuevos bloques de poder. Así, podremos preguntarnos si el bloque de Unasur es estructurado sobre nuevas lógicas de construcción de poder. Su estudio permitirá también indagar en los desafíos que su conformación plantea y en las tensiones y en los conflictos de intereses que los distintos propósitos de integración que conviven en Unasur conllevan

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Los procesos de integración latinoamericana vienen siendo estudiados desde hace tiempo, y su abordaje plantea múltiples dimensiones para la investigación social. En el presente trabajo se indagan algunas de las características de la territorialidad en la región suramericana para preguntarse por algunos de los procesos de integración que atañen a Suramérica, particularmente respecto del bloque UNASUR, poniendo especial énfasis en las transformaciones que han operado en las últimas décadas. El enfoque territorial será la lupa a través de la cual se intentará tener un primer acercamiento al fenómeno atravesado por dinámicas de poder más amplias y más complejas. Se comienza con una reflexión inicial en torno a los modos de concebir analíticamente el territorio, que está invadido por múltiples lógicas y mecanismos de poder. El recorrido por los debates sobre las modalidades de inserción internacional, así como por las etapas de regionalismo en Latinoamérica, contribuirá a la descripción de las nuevas condiciones que se dan en la región a la hora de analizar el surgimiento de nuevos bloques de poder. Así, podremos preguntarnos si el bloque de Unasur es estructurado sobre nuevas lógicas de construcción de poder. Su estudio permitirá también indagar en los desafíos que su conformación plantea y en las tensiones y en los conflictos de intereses que los distintos propósitos de integración que conviven en Unasur conllevan

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Study of biogeochemical processes in waters and sediments of the Chukchi Sea in August 2004 revealed atypical maxima of biogenic element (N, P, and Si) concentrations and rate of microbial sulfate reduction in the surface layer (0-3 cm) of marine sediments. The C/N/P ratio in organic matter (OM) of this layer does not fit the Redfield-Richards stoichiometric model. Specific features of biogeochemical processes in the sea are likely related to the complex dynamics of water, high primary produc¬tivity (110-1400 mg C/m**2/day), low depth of the basin (<50 m for 60% of the water area), reduced food chain due to low population of zooplankton, high density of zoobenthos (up to 4230 g/m**2), and high activity of microbial processes. Drastic decrease in concentrations of biogenic elements, iodine, total alkalinity, and population of microorganisms beneath the 0-3 cm layer testify to large-scale OM decay at the water-seafloor barrier. Our original experimental data support high annual rate of OM mineralization at the bottom of the Chukchi Sea.

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South Africa’s first democratic constitution of 1996, which defines the content and scope of citizenship, emerged out of what the country’s Constitutional Court accurately described as ‘a deeply divided society characterized by strife, conflict, untold suffering and injustice which generated gross violations of human rights, the transgression of humanitarian principles in violent conflicts and a legacy of hatred, fear, guilt and revenge’ (cited in Jagwanth, 2003: 7). The constitution was internationally noteworthy for its expressed protection of women’s and sexual minority rights and its extension of rights of citizenship to socio-economic rights, such as rights of adequate healthcare, housing and education (SAGI, 1996). During South Africa’s first two decades of democracy, the Constitutional Court has proven its independence by advancing citizenship rights on a number of occasions (O’Regan, 2012). The struggle for citizenship was at the heart of the liberation struggle against the apartheid regime and within the complex dynamics of the anti-apartheid movement, increasingly sophisticated and intersectional demands for citizenship were made. South Africa’s constitutional rights for citizenship are not always matched in practice. The country’s high rates of sexual violence, ongoing poverty and inequality and public attitudes towards the rights of sexual minorities and immigrants lag well behind the spirit and letter of the constitution. Nevertheless, the achievement of formal citizenship rights in South Africa was the result of a prolonged and complex liberation struggle and analysis of South Africa demonstrates Werbner’s claim that ‘struggles over citizenship are thus struggles over the very meaning of politics and membership in a community’ (1999: 221). This chapter will begin with a contextual and historical overview before moving onto analyzing the development of non-racialism as a basis for citizenship, non-sexism and gendered citizenship, contestations of white, militarized citizenship and the achievement of sexual citizenship by the Lesbian, Gay, Bisexual and Transgender (LGBT) rights movement. As shall be made clear, all these citizenship demands emerged during the decades of the country’s liberation struggle.

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Die neuen Paradigmen der Rechtswissenschaft nötigen uns beim Erwerb juristischen Wissens dazu, uns in eine kreativere und problemorientiertere Dynamik des Lehrens-Lernens einzugliedern. Die neuen Generationen der Rechtsgelehrten sollten darum bemüht sein, die verschiedenen theoretisch-methodologischen Strömungen des Rechts, z.B. des juristischen Realismus, den juristischen Strukturalismus sowie die angewandte juristische Soziologie zu studieren und zu analysieren. Andererseits sollten sie nicht dogmatisch und ausschliesslich den juristischen Positivismus des 19. Jahrhunderts vertreten. Die juristischen Fakultäten und Schulen der Republik Mexiko zeichnen sich dadurch aus, dass sie die traditionelle juristische Lehre bewahren. Darin liegt der Grund, dass es nur wenige Juristen gibt, die sich der juristischen Forschung und der wissenschaftlichen Praxis widmen.

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Dans cette thèse, nous avons analysé le déroulement d’un processus de municipalisation du système de santé, effectué au Rio Grande do Norte (RN), un des états fédérés du nord-est du Brésil. En tenant compte des contextes historiques d’implantation, nous avons centré notre attention sur la contribution des acteurs impliqués dans ce processus, spécialement dans l’allocation des ressources financières du système. Les croyances, perceptions, attentes, représentations, connaissances, intérêts, l’ensemble des facteurs qui contribuent à la constitution des capacités cognitives de ces acteurs, favorise la réflexivité sur leurs actions et la définition de stratégies diverses de façon à poursuivre leurs objectifs dans le système de santé. Ils sont vus ainsi comme des agents compétents et réflexifs, capables de s’approprier des propriétés structurelles du système de santé (règles et ressources), de façon à prendre position dans l’espace social de ce système pour favoriser le changement ou la permanence du statu quo. Au cours du processus de structuration du Système unique de santé brésilien, le SUS, la municipalisation a été l’axe le plus développé d’un projet de réforme de la santé. Face aux contraintes contextuelles et de la dynamique complexe des espaces sociaux de la santé, les acteurs réformistes n’ont pas pu suivre le chemin de l’utopie idéalisée; quelques détours ont été parcourus. Au RN, la municipalisation de la santé a constitué un processus très complexe où la triade centralisation/décentralisation/recentralisation a suivi son cours au milieu de négociations, de conflits, d’alliances, de disputes, de coopérations, de compétitions. Malgré les contraintes des contextes successifs, des propriétés structurelles du système et des dynamiques sociales dans le système de santé, quelques changements sont intervenus : la construction de leaderships collectifs; l’émergence d’une culture de négociation; la création des structures et des espaces sociaux du système, favorisant les rencontres des acteurs dans chaque municipalité et au niveau de l’état fédéré; un apprentissage collectif sur le processus de structuration du SUS; une grande croissance des services de première ligne permettant d’envisager une inversion de tendance du modèle de prestation des services; les premiers pas vers la rupture avec la culture bureaucratique du système. Le SUS reste prisonnier de quelques enjeux institutionnalisés dans ce système de santé : la dépendance du secteur privé et de quelques groupes de professionnels; le financement insuffisant et instable; la situation des ressources humaines. Les changements arrivés sont convergents, incrémentiels, lents; ils résultent d’actions normatives, délibérées, formalisées. Elles aussi sont issues de l’inattendu, de l’informel, du paradoxe; quelques-unes plus localisées, d’autres plus généralisées, pour une courte ou une plus longue durée.

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Local communities collectively managing common pool resources can play an important role in sustainable management, but they often lack the skills and context-specific tools required for such management. The complex dynamics of social-ecological systems (SES), the need for management capacities, and communities’ limited empowerment and participation skills present challenges for community-based natural resource management (CBNRM) strategies. We analyzed the applicability of prospective structural analysis (PSA), a strategic foresight tool, to support decision making and to foster sustainable management and capacity building in CBNRM contexts and the modifications necessary to use the tool in such contexts. By testing PSA in three SES in Colombia, Mexico, and Argentina, we gathered information regarding the potential of this tool and its adaptation requirements. The results suggest that the tool can be adapted to these contexts and contribute to fostering sustainable management and capacity building. It helped identify the systems’ dynamics, thus increasing the communities’ knowledge about their SES and informing the decision-making process. Additionally, it drove a learning process that both fostered empowerment and built participation skills. The process demanded both time and effort, and required external monitoring and facilitation, but community members could be trained to master it. Thus, we suggest that the PSA technique has the potential to strengthen CBNRM and that other initiatives could use it, but they must be aware of these requirements.

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O organismo humano encontra-se colonizado por uma complexa diversidade de microrganismos. O conjunto destes microrganismos, que incluem as bactérias, fungos, vírus e protozoários, no homem denomina- se microbioma humano. Estima-se que entre a superfície interna e externa, o microbioma humano seja composto por 100 triliões de microrganismos. O microbioma humano varia muito nas mais diversas regiões do nosso corpo, dependendo de condições ambientais. Sabe-se, por exemplo, que nas regiões mais húmidas e quentes encontram-se uma maior concentração de microrganismos, enquanto que nas regiões menos húmidas, existe uma quantidade menor de microrganismos. O microbioma é de vital importância para a saúde humana, e o seu estudo conduz a um melhor conhecimento da sua complexa dinâmica, podendo conduzir ao desenvolvimento de novas formas de diagnóstico e até mesmo de tratamento de certas patologias. Assim sendo, a compreensão da diversidade fisiológica humana, bem como a de outros animais, passa pelo conhecimento da distribuição destes microrganismos nos diferentes órgãos e seu papel biológico. O desenvolvimento de técnicas de genética permitiram o estudo metagenómico importante para descrever a diversidade do microbioma humano, que não seria possível através da cultura das espécies pois um grande número destas não é cultivável. Esta dissertação tem como principal objetivo descrever o microbioma humano e de que forma esta influência o sistema imunitário. E numa segunda parte dar uma visão sobre a importância da análise metagenómica na identificação e caraterização do microbioma Humano.

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It is nowadays recognized that the risk of human co-exposure to multiple mycotoxins is real. In the last years, a number of studies have approached the issue of co-exposure and the best way to develop a more precise and realistic assessment. Likewise, the growing concern about the combined effects of mycotoxins and their potential impact on human health has been reflected by the increasing number of toxicological studies on the combined toxicity of these compounds. Nevertheless, risk assessment of these toxins, still follows the conventional paradigm of single exposure and single effects, incorporating only the possibility of additivity but not taking into account the complex dynamics associated to interactions between different mycotoxins or between mycotoxins and other food contaminants. Considering that risk assessment is intimately related to the establishment of regulatory guidelines, once the risk assessment is completed, an effort to reduce or manage the risk should be followed to protect public health. Risk assessment of combined human exposure to multiple mycotoxins thus poses several challenges to scientists, risk assessors and risk managers and opens new avenues for research. This presentation aims to give an overview of the different challenges posed by the likelihood of human co-exposure to mycotoxins and the possibility of interactive effects occurring after absorption, towards knowledge generation to support a more accurate human risk assessment and risk management. For this purpose, a physiologically-based framework that includes knowledge on the bioaccessibility, toxicokinetics and toxicodynamics of multiple toxins is proposed. Regarding exposure assessment, the need of harmonized food consumption data, availability of multianalyte methods for mycotoxin quantification, management of left-censored data and use of probabilistic models will be highlight, in order to develop a more precise and realistic exposure assessment. On the other hand, the application of predictive mathematical models to estimate mycotoxins’ combined effects from in vitro toxicity studies will be also discussed. Results from a recent Portuguese project aimed at exploring the toxic effects of mixtures of mycotoxins in infant foods and their potential health impact will be presented as a case study, illustrating the different aspects of risk assessment highlighted in this presentation. Further studies on hazard and exposure assessment of multiple mycotoxins, using harmonized approaches and methodologies, will be crucial towards an improvement in data quality and contributing to holistic risk assessment and risk management strategies for multiple mycotoxins in foodstuffs.

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Dans cette thèse, nous avons analysé le déroulement d’un processus de municipalisation du système de santé, effectué au Rio Grande do Norte (RN), un des états fédérés du nord-est du Brésil. En tenant compte des contextes historiques d’implantation, nous avons centré notre attention sur la contribution des acteurs impliqués dans ce processus, spécialement dans l’allocation des ressources financières du système. Les croyances, perceptions, attentes, représentations, connaissances, intérêts, l’ensemble des facteurs qui contribuent à la constitution des capacités cognitives de ces acteurs, favorise la réflexivité sur leurs actions et la définition de stratégies diverses de façon à poursuivre leurs objectifs dans le système de santé. Ils sont vus ainsi comme des agents compétents et réflexifs, capables de s’approprier des propriétés structurelles du système de santé (règles et ressources), de façon à prendre position dans l’espace social de ce système pour favoriser le changement ou la permanence du statu quo. Au cours du processus de structuration du Système unique de santé brésilien, le SUS, la municipalisation a été l’axe le plus développé d’un projet de réforme de la santé. Face aux contraintes contextuelles et de la dynamique complexe des espaces sociaux de la santé, les acteurs réformistes n’ont pas pu suivre le chemin de l’utopie idéalisée; quelques détours ont été parcourus. Au RN, la municipalisation de la santé a constitué un processus très complexe où la triade centralisation/décentralisation/recentralisation a suivi son cours au milieu de négociations, de conflits, d’alliances, de disputes, de coopérations, de compétitions. Malgré les contraintes des contextes successifs, des propriétés structurelles du système et des dynamiques sociales dans le système de santé, quelques changements sont intervenus : la construction de leaderships collectifs; l’émergence d’une culture de négociation; la création des structures et des espaces sociaux du système, favorisant les rencontres des acteurs dans chaque municipalité et au niveau de l’état fédéré; un apprentissage collectif sur le processus de structuration du SUS; une grande croissance des services de première ligne permettant d’envisager une inversion de tendance du modèle de prestation des services; les premiers pas vers la rupture avec la culture bureaucratique du système. Le SUS reste prisonnier de quelques enjeux institutionnalisés dans ce système de santé : la dépendance du secteur privé et de quelques groupes de professionnels; le financement insuffisant et instable; la situation des ressources humaines. Les changements arrivés sont convergents, incrémentiels, lents; ils résultent d’actions normatives, délibérées, formalisées. Elles aussi sont issues de l’inattendu, de l’informel, du paradoxe; quelques-unes plus localisées, d’autres plus généralisées, pour une courte ou une plus longue durée.

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A qualitative study was conducted in a large urban school district in the Mid-Atlantic region of the Unites States to investigate the perceptions of parents and teachers regarding the adjustment to sixth grade across school configurations. The investigation revealed the psychosocial and environmental factors that have an impact on sixth graders according to their grade span configurations. The study was conducted in the large urban school district, referred to as the “County,” which has a history of low and inconsistent achievement of sixth graders across a variety of grade span configurations. Through the analysis of the teacher and parent interviews conducted in two K-6 schools and two 6-8 middle schools, four themes were identified: transitioning, cultural awareness, social adjustment, and preparedness. The four themes emerged from the perceptions and observations of sixth graders, as shared by parents and teachers of sixth graders, according to their grade span configurations. Each of the responses was compared according to the identified grade span configuration K-6 and 6-8. From the data collected, recommendations were provided to the school district in which the study was conducted to better support teachers, parents, and sixth graders. Further research was also recommended of larger samples of sixth grade span configurations to better understand the complex dynamics of the relationships between grade span configurations for sixth graders and student achievement.

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Dissertação (mestrado)—Universidade de Brasília, Instituto de Química, Programa de Pós-Graduação em Química, 2016.

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A primary goal of this dissertation is to understand the links between mathematical models that describe crystal surfaces at three fundamental length scales: The scale of individual atoms, the scale of collections of atoms forming crystal defects, and macroscopic scale. Characterizing connections between different classes of models is a critical task for gaining insight into the physics they describe, a long-standing objective in applied analysis, and also highly relevant in engineering applications. The key concept I use in each problem addressed in this thesis is coarse graining, which is a strategy for connecting fine representations or models with coarser representations. Often this idea is invoked to reduce a large discrete system to an appropriate continuum description, e.g. individual particles are represented by a continuous density. While there is no general theory of coarse graining, one closely related mathematical approach is asymptotic analysis, i.e. the description of limiting behavior as some parameter becomes very large or very small. In the case of crystalline solids, it is natural to consider cases where the number of particles is large or where the lattice spacing is small. Limits such as these often make explicit the nature of links between models capturing different scales, and, once established, provide a means of improving our understanding, or the models themselves. Finding appropriate variables whose limits illustrate the important connections between models is no easy task, however. This is one area where computer simulation is extremely helpful, as it allows us to see the results of complex dynamics and gather clues regarding the roles of different physical quantities. On the other hand, connections between models enable the development of novel multiscale computational schemes, so understanding can assist computation and vice versa. Some of these ideas are demonstrated in this thesis. The important outcomes of this thesis include: (1) a systematic derivation of the step-flow model of Burton, Cabrera, and Frank, with corrections, from an atomistic solid-on-solid-type models in 1+1 dimensions; (2) the inclusion of an atomistically motivated transport mechanism in an island dynamics model allowing for a more detailed account of mound evolution; and (3) the development of a hybrid discrete-continuum scheme for simulating the relaxation of a faceted crystal mound. Central to all of these modeling and simulation efforts is the presence of steps composed of individual layers of atoms on vicinal crystal surfaces. Consequently, a recurring theme in this research is the observation that mesoscale defects play a crucial role in crystal morphological evolution.

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The thermal behavior of kaolinite–urea intercalation complex was investigated by thermogravimetry–differential scanning calorimetry (TG–DSC), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FTIR). In addition, the interaction mode of urea molecules intercalated into the kaolinite gallery was studied by means of molecular dynamics simulation. Three main mass losses were observed at 136 °C, in the range of 210–270 °C, and at 500 °C in the TG–DSC curves, which were, respectively, attributed to (1) melting of the surface-adsorbed urea, (2) removal of the intercalated urea, and (3) dehydroxylation of the deintercalated kaolinite. The three DSC endothermic peaks at 218, 250, and 261 °C were related to the successive removals of intercalated urea with three different distribution structures. Based on the angle between the dipole moment vector of urea and the basal surface of kaolinite, the three urea models could be described as follows: (1) Type A, the dipole moment vector is nearly parallel to the basal surface of kaolinite; (2) Type B, the dipole moment vector points to the silica tetrahedron with the angle between it and the basal surface of kaolinite ranging from 20°to 40°; and (3) Type C, the dipole moment vector is nearly perpendicular to the basal surface of kaolinite. The three distribution structures of urea molecules were validated by the results of the molecular dynamics simulation. Furthermore, the thermal behavior of the kaolinite–urea intercalation complex investigated by TG–DSC was also supported by FTIR and XRD analyses.