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Fragmentation of Green Spaces : A case study of the impact of green space fragmentation on humans and roe deer in Uppsala municipalityAndersson, Rebecka January 2024 (has links)
Green space fragmentation is one reason for the failing ecological networks around our planet. It has been argued that the driving force behind the loss of natural habitats by fragmentation is urban development. This essay aims to look at the subject of green space fragmentation in Uppsala municipality and how it affects both humans and roe deer living in the area. This essay will also explore how the efforts to stop wildlife-vehicle collisions impact roe deer’s ability to roam through the area divided thanks to human induced green space fragmentation. This has been done by using a descriptive quantitative analysis combined with a connectivity model, the least-cost approach. Remote sensing was used to collect the data used for the analysis. The results of this essay indicated that green space fragmentation impacts both humans and roe deer in Uppsala municipality since the wildlife-vehicle collisions can be traced to spots where the roe deer are forced to cross the road because of green space fragmentation. The introduced form of wildlife crossing structures, wildlife fences, does not help minimize the effects of the fragmentation, instead it steers the animals into certain points where the collisions occur. To truly minimize the consequences of human induced green space fragmentation, green infrastructure needs to be taken into account whenever planning future developments.
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Emergent Phenomena in Quantum Dynamics of Non-Thermal Systems:Han, Yiqiu January 2024 (has links)
Thesis advisor: Xiao Chen / The development of highly controllable quantum coherent simulators such as superconducting qubits and Rydberg atom arrays has stimulated the study of non-equilibrium quantum dynamics, opening the door to exciting topics including dynamical phase transitions, thermalization, transport, and quantum error correction. This thesis addresses various questions from non-equilbrium quantum dynamics, with a concentration on measurement-induced phase transitions (MIPT), adaptive dynamics with feedback mechanism, and Hilbert space fragmentation. In the first part, we study the hybrid quantum automaton (QA) circuits with different symmetries subject to local composite measurements. For $\mathbb{Z}_2$-symmetric hybrid QA circuits, there exists an entanglement phase transition from a volume-law phase to a critical phase by varying the measurement rate. The special feature of QA circuits enables us to interpret the entanglement dynamics in terms of a stochastic particle model. With the help of this stochastic model, we further investigate the entanglement fluctuations and quantum error correcting property of the volume-law phase in QA circuits with no symmetry, and study the entanglement dynamics in QA circuits with U(1) symmetry. Despite being a hallmark of non-unitary quantum dynamics, MIPT is absent in the density matrix averaged over measurement outcomes. In the second part, we introduce an adaptive quantum circuit subject to measurements with feedback. The feedback is applied according to the measurement outcome and steers the system towards a unique state above certain measurement threshold. We show that there exists an absorbing phase transition in both quantum trajectories and quantum channels. In the end, we turn to the phenomenon of Hilbert space fragmentation (HSF), whereby dynamical constraints fragment Hilbert space into many disconnected sectors, providing a simple mechanism by which thermalization can be arrested. However, little is known about how thermalization occurs in situations where the constraints are not exact. To study this, we consider a situation in which a fragmented 1d chain with pair-flip constraints is coupled to a thermal bath at its boundary. For product states quenched under Hamiltonian dynamics, we numerically observe an exponentially long thermalization time, manifested in both entanglement dynamics and the relaxation of local observables. To understand this, we study an analogous model of random unitary circuit dynamics, where we rigorously prove that the thermalization time scales exponentially with system size. Slow thermalization in this model is shown to be a consequence of strong bottlenecks in configuration space, demonstrating a new way of producing anomalously slow thermalization dynamics. / Thesis (PhD) — Boston College, 2024. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Physics.
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Mega-eventos e produção do espaço urbano no Rio de Janeiro: da \"Paris dos Trópicos\" à \"Cidade Olímpica\" / Mega-events and the production of urban space in Rio de Janeiro: from \"Paris of the Tropics\" to \"Olympic City\"Molina, Fabio Silveira 05 March 2013 (has links)
O tema central desta tese se assenta no papel dos mega-eventos no processo de produção do espaço urbano do Rio de Janeiro desde o início do século XX, marcado pela produção da Paris dos Trópicos, até o momento atual inerente à produção da Cidade Olímpica. Os mega-eventos, configurando-se como verdadeiros espetáculos de ampla abrangência e visibilidade, são acompanhados de megaprojetos urbanos e induzem a diversas intervenções espaciais nas cidades, manifestadas materialmente através da construção de edificado, obras de infraestrutura, conquista de novos terrenos e ressignificações de usos e funções de áreas inteiras. Neste sentido, a partir de seus desdobramentos espaciais, compreende-se a importância que os mesmos possuem nos processos de fragmentação espacial, ao produzir parcelas do espaço valorizadas e vendidas enquanto solo urbano e, ainda, no reforço ou consolidação de áreas de centralidade, por induzir à concentração de investimentos e pessoas, e dinamizar o comércio, os serviços e os fluxos diversos no espaço intra-urbano da cidade, nossa escala de análise. Esta reflexão partiu da identificação do primeiro mega-evento realizado no Rio de Janeiro, a Exposição Nacional de 1908, seguida de outros cujas expressões concretas materializaram-se na cidade, impactando a estrutura urbana carioca em diferentes momentos, a saber: a Exposição Internacional de 1922, a Copa do Mundo de 1950, a Conferência das Nações Unidas sobre o Meio Ambiente e Desenvolvimento (Rio-92), os Jogos Pan-Americanos de 2007 e, uma vez que o Rio de Janeiro sediará os Jogos Olímpicos de 2016, nossa análise se estende à estruturação da cidade nos dias atuais, norteada pela realização desse megaevento. / The central theme of this thesis is based on the role of mega-events in the production of Rio de Janeiro´s urban space from the early twentieth century, marked by the production of the \"Paris of the Tropics\", to the current moment inherent in the production of the \"Olympic City\". Mega-events, configured as spectacles of broad scope and visibility, are accompanied by urban mega-projects and induce to various spatial interventions in the cities, expressed materially by building constructions, infrastructure, conquest of new lands and new uses and functions of entire areas. In this sense, from these spatial expressions, we understand the importance they have in the processes of spatial fragmentation, as long as they produce fractions of space valued and sold as urban land and, also, in strengthening or consolidating areas of centrality, inducing the concentration of people and investments, and boost commerce, services and the various flows in intra-urban space of the city, which is our scale of analysis. This reflection came from the identification of the first megaevent held in Rio de Janeiro, the 1908 National Exhibition, followed by others which concrete expressions materialized in the city and impacted at different times of the urban structure: the 1922 International Exhibition, the World Cup of 1950, the United Nations Conference on Environment and Development (Rio-92), the Pan-American Games in 2007 and, since Rio de Janeiro will host the forthcoming Olympic Games in 2016, our analysis extends to the impacts on the structure of the city in current days, guided by the realization of this mega-event.
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Mega-eventos e produção do espaço urbano no Rio de Janeiro: da \"Paris dos Trópicos\" à \"Cidade Olímpica\" / Mega-events and the production of urban space in Rio de Janeiro: from \"Paris of the Tropics\" to \"Olympic City\"Fabio Silveira Molina 05 March 2013 (has links)
O tema central desta tese se assenta no papel dos mega-eventos no processo de produção do espaço urbano do Rio de Janeiro desde o início do século XX, marcado pela produção da Paris dos Trópicos, até o momento atual inerente à produção da Cidade Olímpica. Os mega-eventos, configurando-se como verdadeiros espetáculos de ampla abrangência e visibilidade, são acompanhados de megaprojetos urbanos e induzem a diversas intervenções espaciais nas cidades, manifestadas materialmente através da construção de edificado, obras de infraestrutura, conquista de novos terrenos e ressignificações de usos e funções de áreas inteiras. Neste sentido, a partir de seus desdobramentos espaciais, compreende-se a importância que os mesmos possuem nos processos de fragmentação espacial, ao produzir parcelas do espaço valorizadas e vendidas enquanto solo urbano e, ainda, no reforço ou consolidação de áreas de centralidade, por induzir à concentração de investimentos e pessoas, e dinamizar o comércio, os serviços e os fluxos diversos no espaço intra-urbano da cidade, nossa escala de análise. Esta reflexão partiu da identificação do primeiro mega-evento realizado no Rio de Janeiro, a Exposição Nacional de 1908, seguida de outros cujas expressões concretas materializaram-se na cidade, impactando a estrutura urbana carioca em diferentes momentos, a saber: a Exposição Internacional de 1922, a Copa do Mundo de 1950, a Conferência das Nações Unidas sobre o Meio Ambiente e Desenvolvimento (Rio-92), os Jogos Pan-Americanos de 2007 e, uma vez que o Rio de Janeiro sediará os Jogos Olímpicos de 2016, nossa análise se estende à estruturação da cidade nos dias atuais, norteada pela realização desse megaevento. / The central theme of this thesis is based on the role of mega-events in the production of Rio de Janeiro´s urban space from the early twentieth century, marked by the production of the \"Paris of the Tropics\", to the current moment inherent in the production of the \"Olympic City\". Mega-events, configured as spectacles of broad scope and visibility, are accompanied by urban mega-projects and induce to various spatial interventions in the cities, expressed materially by building constructions, infrastructure, conquest of new lands and new uses and functions of entire areas. In this sense, from these spatial expressions, we understand the importance they have in the processes of spatial fragmentation, as long as they produce fractions of space valued and sold as urban land and, also, in strengthening or consolidating areas of centrality, inducing the concentration of people and investments, and boost commerce, services and the various flows in intra-urban space of the city, which is our scale of analysis. This reflection came from the identification of the first megaevent held in Rio de Janeiro, the 1908 National Exhibition, followed by others which concrete expressions materialized in the city and impacted at different times of the urban structure: the 1922 International Exhibition, the World Cup of 1950, the United Nations Conference on Environment and Development (Rio-92), the Pan-American Games in 2007 and, since Rio de Janeiro will host the forthcoming Olympic Games in 2016, our analysis extends to the impacts on the structure of the city in current days, guided by the realization of this mega-event.
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