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<p>Thin liquid films are often studied by reducing the Navier-Stokes equations</p><p>using Reynolds lubrication theory, which leverages a small aspect ratio</p><p>to yield simplified governing equations. In this dissertation a plate</p><p>coating application, in which polydimethylsiloxane coats a silicon substrate,</p><p>is studied using this approach. Thermal Marangoni stress</p><p>drives fluid motion against the resistance of gravity, with the parameter</p><p>regime being chosen such that these stresses lead to a stable advancing front.</p><p>Additional localized thermal Marangoni stress is used to control the thin film;</p><p>in particular, coating thickness is modulated through the intensity of such</p><p>localized forcing. As thermal effects are central to film dynamics, the dissertation</p><p>focuses specifically on the effect that incorporating temperature dependence</p><p>into viscosity, surface tension, and density has on film dynamics and control.</p><p>Incorporating temperature dependence into viscosity, in particular,</p><p>leads to qualitative changes in film dynamics.</p><p>A mathematical model is developed in which the temperature dependence</p><p>of viscosity and surface tension is carefully taken into account.</p><p>This model is then</p><p>studied through numerical computation of solutions, qualitative analysis,</p><p>and asymptotic analysis. A thorough comparison is made between the</p><p>behavior of solutions to the temperature-independent and</p><p>temperature-dependent models. It is shown that using</p><p>localized thermal Marangoni stress as a control mechanism is feasible</p><p>in both models. Among constant steady-state solutions</p><p>there is a unique such solution in the temperature-dependent model,</p><p>but not in the temperature-independent model, a feature that</p><p>better reflects the known dynamics of the physical system.</p><p>The interaction of boundary conditions with finite domain size is shown</p><p>to generate both periodic and finite-time blow-up solutions, with</p><p>qualitative differences in solution behavior between models.</p><p>This interaction also accounts for the fact that locally perturbed solutions,</p><p>which arise when localized thermal Marangoni forcing is too weak</p><p>to effectively control thin film thickness, exist only for a discrete</p><p>set of boundary heights.</p><p>Modulating the intensity of localized thermal Marangoni forcing is</p><p>an effective means of modulating the thickness of a thin film</p><p>for a plate coating application; however, such control must be initiated before</p><p>the film reaches the full thickness it would reach in the absence of</p><p>such localized forcing. This conclusion holds for both the temperature-independent</p><p>and temperature-dependent mathematical models; furthermore, incorporating</p><p>temperature dependence into viscosity causes qualitative changes in solution</p><p>behavior that better align with known features of the underlying physical system.</p> / Dissertation

Made available in DSpace on 2015-03-26T13:32:06Z (GMT). No. of bitstreams: 1 texto completo.pdf: 543381 bytes, checksum: 7509b9f65bfa864587d72692479be7a4 (MD5) Previous issue date: 2009-02-18 / Spatial dependence is a tendency that a variable´s value, observed in certain position, leads to approximate to its neighbors value than the value of the rest of the elements observed in the sample. The aim of this work was to evaluate the efficiency of some methods of geostatistic analyses to improve the experimental accuracy of tests that selects families for genetic improvement program of beans plantation. Date set were used to evaluate the productivity of eight experiments set in lattice design, located in Coimbra s Experimental Station controlled by the Plant Science Department at Federal University of Viçosa UFV. For each study was analyzed the neighborhood methods: Moving Means Method, Papadakis Method, Moving Means Replication, Papadakis Method Replication and the method that contains errors dependent in the comparison between traditional analyses in lattice which do not consider the spatial dependence among plots according to its fitting model, and the family classification in study. The existence of experiment s spatial dependence was observed through the Durbin-Watson s test, empirical and theoretical semivariogram with a geostatistic fitting model for residues checking the coherence of data and noticing the occurrence of spatial dependence in 6 out of 8 experiments in study (Chapter1). Five out of the six experiments showed spatial dependence for analyses in blocks and one for analyses in lattice and blocks, reaching 2.6 to 33.3m. In chapter 2, it was used the Durbin-Watson s test to observe the spatial dependence among residues for different methodologies, besides the Akaike Information Criteria (AIC) and the Maximum Likelihood Method to compare the fitting model. The variation coefficient and the relative efficiency were used to compare the efficiency of tested methodologies related to the analyses in lattice. The Spearman s Correlation Coefficient and the efficiency of selection were also used to compare the classification of beans plantation families acquired through the analyses in lattice and through the spatial analyses method. It was noticed that the spatial analyses method had a better fitting to the data than the methods that assume independent errors. The experiments accuracy, the analyses in lattice efficiency was higher compared to the analyses in blocks when there is higher spatial dependence. The spatial analyses method, Moving Means Method, Papadakis Method and the method with independent errors showed reasonable efficiency, while the proposed methodologies, Moving Means Replication and Papadakis were highly efficient than the analyses in lattice. Papadakis replication Method showed to be more efficient once its neighborhood is constituted by a superior and inferior plot compared to the reference plot. The tested methods showed reasonable concordance level compared to the selected families for analyses in lattice. The Moving Means Replication and Papadakis Replication methodologies showed highly efficient to improve the experiments accuracy, besides to guarantee the independence among residues, being an excellent alternative for analyses compared to the analyses in lattice. / A dependência espacial é a propensão pela qual o valor de uma variável observada em certa posição tende a assemelhar-se mais aos valores vizinhos do que ao restante das observações do conjunto amostral. O objetivo deste trabalho foi a avaliação da eficiência de alguns métodos de análise estatística espacial para melhorar a precisão experimental em ensaios de seleção de famílias em programa de melhoramento genético do feijoeiro. Foram utilizados dados para produtividade de oito experimentos montados em látice, conduzidos na estação experimental de Coimbra, pertencente ao Departamento de Fitotecnia da Universidade Federal de Viçosa (UFV). Para cada análise, foram analisados os métodos de análise de vizinhança: método das médias móveis, método de Papadakis, reaplicação das médias móveis, reaplicação do método Papadakis e o método com erros dependentes em comparação com a análise tradicional em látice, que desconsidera a dependência espacial entre parcelas quanto ao ajuste dos modelos e à classificação das famílias avaliadas. Foi verificada a existência da dependência espacial nos experimentos pelo teste de Durbin-Watson, semivariograma empírico e teórico com o ajustamento de um modelo geoestatístico para resíduos, verificando a coerência dos dados e percebendo a ocorrência da dependência espacial em seis dos oito experimentos avaliados (capítulo 1). Dos seis experimentos, cinco apresentaram dependência espacial para análise em blocos e um para análise em látice e em blocos, com alcance variando de 2,6 a 33,3 m. No capítulo 2, foram utilizados o teste de Durbin-Watson para verificar a dependência espacial entre resíduos para as diferentes metodologias, além do critério de informação de Akaike (AIC) e do teste da razão da verossimilhança (LRT) para comparar o ajuste dos modelos. Utilizaram-se o coeficiente de variação e a eficiência relativa para comparar a eficiência das metodologias testadas em relação à análise em látice. Também foram utilizados o coeficiente de correlação de Spearman e a eficiência de seleção para comparar as classificações de famílias do feijoeiro obtidas na análise em látice e pelos métodos de análise espacial. Verificou-se que os métodos de análise espacial ajustaram-se melhor aos dados em relação aos métodos que assumem erros independentes. Quanto à precisão experimental, a eficiência da análise em látice foi maior em relação à análise em blocos quando há maior dependência espacial. Os métodos de análise espacial, médias móveis, Papadakis e o método com erros dependentes apresentaram razoável eficiência, enquanto as metodologias propostas, reaplicações das médias móveis e Papadakis foram altamente eficientes em relação à análise em látice, sendo mais eficiente o método reaplicação de Papadakis cuja vizinhança é composta por uma parcela superior e uma inferior em relação à parcela referência. Os métodos testados apresentaram razoável nível de concordância em relação às famílias selecionadas na análise em látice. As metodologias de reaplicação de médias móveis e reaplicação de Papadakis mostram-se altamente eficientes para melhorar a precisão experimental, além de conseguir garantir a independência entre resíduos, sendo uma excelente alternativa de análise em relação à análise em látice.

Made available in DSpace on 2015-03-26T13:32:13Z (GMT). No. of bitstreams: 1 texto completo.pdf: 739954 bytes, checksum: 58f3879d83e13777643ea5fe0ef74001 (MD5) Previous issue date: 2011-06-20 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The general objective of this work was to evaluate if estimates of wood volume obtained from geostatistics techniques are more accurate than those obtained from classical statistical techniques.The study was conducted in stands of Tectona grandis L.f. with the dendometric volume trait measured in 101 plots laid along a sampling spacing with UTM coordinates, distributed in 17 plots with a total area of 391.87 ha. By adjusting the experimental semivariogram model, index of spatial dependence and cross-validation statistics it was obtained two estimates of the forest inventory: one by using the classical statistics and the other by using geostatistics. Methodology of systematic sampling with intensity of sampling of one plot for every 4 ha was used in the conduction of the classical estimation. A semivariogram model, used to assess the structure of spatial dependence of the variable volume per ha in the study area was adjusted in the prediction by geostatistcs. Then, block kriging was used to obtain predictions of the average volume of each plot. Comparison of the two methods of estimation was made based on the sampling error, in which a minor error with geostatistics was found. Therefore, it is concluded geostatistics should be used for forest inventory when there is spatial dependence structure in the region under study inasmuch as it provides more accurate predictions. / Este trabalho teve por objetivos geral avaliar se as estimativas do volume de madeira obtidas a partir de técnicas geoestatísticas são mais precisas do que as obtidas a partir de técnicas da estatística clássica. O estudo foi realizado em povoamentos de Tectona grandis L.f. com a característica dendrométrica de volume mensurada em 101 parcelas lançadas ao longo de uma malha de amostragem com coordenadas UTM, distribuídas em 17 talhões, com uma área total de 391,87 ha. Com o ajuste do modelo semivariograma experimental, do índice de dependência espacial e das estatísticas da validação cruzada, foram obtidas duas estimativas do inventário florestal: uma utilizando estatística clássica e a outra, geoestatística. Na realização da estimação clássica, foi considerada a metodologia de amostragem sistemática, com a intensidade de amostragem de uma parcela para cada 4 ha. Na predição por geoestatística, foi ajustado o modelo de semivariograma, utilizado para avaliar a estrutura de dependência espacial da variável volume por ha na área de estudo. Em seguida, utilizou-se a krigagem em blocos para obter as predições do volume médio de cada talhão. A comparação das estimações dos dois métodos foi feita com base no erro de amostragem, sendo encontrado um menor erro com a geoestatística. Conclui-se, assim, o uso da geoestatística para realização de inventário florestal, quando existir estrutura de dependência espacial na região em estudo, uma vez que ela fornece predições mais precisas.

Made available in DSpace on 2015-03-26T13:32:16Z (GMT). No. of bitstreams: 1 texto completo.pdf: 862787 bytes, checksum: b23a777918d630895ac6bf3d64e985c8 (MD5) Previous issue date: 2012-07-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In recent years Geostatistics has been widely used in the field of precision agriculture, this is due to being a tool to analyze the spatial variability exists in the area of agricultural production, enabling assess the need for creation of subareas or zones where they are handlings performed differently. One focus of precision agriculture is to identify management zones within the field based on the variability, and through Geostatistics is possible to produce thematic maps that assist in the establishment of management zones through adjustments of models of spatial dependence. The objective of this study was to analyze the influence of models of spatial dependence in the definition of thematic maps of management zones, using different models and different semivariogram sampling grids. To conduct the study, we analyzed simulated data generated in SAS software, where he held various structures of spatial dependence (DE) and different sampling grids (grid), with different sizes and densities of points, with a total of 9 data set simulated. To analyze the spatial dependence structure experimental semivariograms were used and adjusted three theoretical models to experimental semivariogram: exponential, spherical and Gaussian for each data set under study, according to the parameters set forth by autotune software ArcGis 9.3. Were adjusted 27 different semivariogram models using the method of ordinary kriging and through cross-validation technique checked the fit of the models semivariográficos. Thematic maps management zones were generated from the technique of kriging, and with the aid of software Idrisi was performed to compare the maps using Kappa Index of agreement, which was tested by testing their significance Z. From the analyzes, it was concluded that the model of spatial dependence does not influence the definition of thematic maps of management zones. / Nos últimos anos a Geoestatística vem sendo amplamente utilizada na área de agricultura de precisão, isso se deve ao fato de ser uma ferramenta que permite analisar a variabilidade espacial existente na área de produção agrícola, possibilitando avaliar a necessidade de criação de subáreas ou zonas onde serão realizados manejos de forma diferenciada. Um dos focos da agricultura de precisão é a identificação de zonas de manejo dentro do campo baseadas na variabilidade existente, e por meio da Geoestatística é possível produzir os mapas temáticos que auxiliam no estabelecimento das zonas de manejo através de ajustes de modelos de dependência espacial. Assim, o objetivo geral deste estudo foi analisar a influência de modelos de dependência espacial na definição de mapas temáticos de zonas de manejo, usando diferentes modelos de semivariogramas e diferentes grades de amostragem. Para a realização do estudo foram analisados dados simulados gerados no software SAS, onde se considerou diferentes estruturas de dependência espacial (DE) e diferentes grades de amostragens (grid), com diferentes tamanhos e densidades de pontos, sendo um total de 9 conjunto de dados simulados. Para a análise da estrutura de dependência espacial foram utilizados semivariogramas experimentais e ajustados três modelos teóricos ao semivariograma experimental: exponencial, esférico e gaussiano, para cada conjunto de dados em estudo, conforme os parâmetros estipulados pelo auto-ajuste do software ArcGis 9.3. Foram ajustados 27 diferentes modelos de semivariogramas através do método da krigagem ordinária e através da técnica de validação-cruzada verificados os ajustes dos modelos semivariográficos. Mapas temáticos de zonas de manejo foram gerados a partir da técnica de krigagem ordinária, e com o auxilio do software Idrisi foi realizada a comparação dos mapas através do Índice Kappa de concordância, o qual foi testado sua significância através do teste Z. A partir das análises realizadas, concluindo-se que o modelo de dependência espacial não influencia na definição de mapas temáticos de zonas de manejo.

Non-Governmental Organisations (NGOs) play an increasingly important role in the world and receive a growing amount of outsourced development work. Funding enables them to do the work necessary to provide aid. NGO work is influenced by the dependence on their donors and many NGOs increasingly take donations from private donors as a way to try to mitigate donor dependence and maintain neutrality in their work. However there is little research analysing this shift and the potential positive and negative effects. This study looks at dependence and efficiency in an NGO - private donor relationship. The objective is to contribute to the discussion about NGO dependency on donors by evaluating the positive and negative impacts of primarily private donorship on NGOs’ work efficiency. Little research has been done on the private donor relationship and this study is contributing to filling that gap. The study is a qualitative case study, with Médecins Sans Frontières (MSF) due to their private donor base’s recent increase. The data were obtained through interviews with MSF Sweden staff, other MSF primary source documents and secondary sources written by scholars on the topic of NGO dependency on their donors. The results of this study concluded that MSF works more efficiently with a primarily private donor base, due primarily to their increase in independence and control of their own operations. Since the shift from EU-funding, MSF can spend fewer resources on reporting and more on allocating the money to the field. A primarily private donor base has a positive impact on MSF and it is safe to say that other NGOs will likely follow suit. Further research should look into other NGOs to see whether a primarily private donor base benefits them too or if MSF is a one case exception.

Ever since the introduction of the railway through Stockholm there have been issues regardingcapacity. Citybanan is a recently built railway tunnel for commuter trains that takes somepressure off the heavily frequented stretch of tracks in the center of Stockholm. The projecttook almost 30 years to complete and led to time delays as well as large cost increases. Usinga theoretic background of path dependence and megaproject theories the planning is beingexamined. The conclusions of this study are that the investigations are influenced by pathdependence, mainly because the Swedish government early on decided upon reserving moneyto a specific project which did not turn out to be the technically best project. This pathdependence is related to the megaproject theory that projects that lock onto a specific idea oftenget delayed. The overrun might have been prevented by comparing Citybanan to other finishedrailway projects during early stages of the investigation.

Orientador: Milton Lahuerta / Banca: Alberto Rocha Valencia / Banca: Vera Alves Cepeda / Banca: Fausto Saretta / Banca: Marcelo Santos / Resumo: O objetivo do trabalho é analisar como o governo de Hugo Chávez se propôs a refundação do Estado venezuelano, através de um processo de elaboração de uma nova constituição e com base numa retórica nacionalista e bolivariana, que pretendia transformar radicalmente a estrutura econômica, mas acabou sendo limitado pela força da permanência do legado institucional do país construído sobre a dependência do petróleo e a lógica rentista. Para tanto, nos utilizamos de autores que trabalham com a dimensão institucional do desenvolvimento econômico e se preocupam em explicar porque diante de condições materiais parecidas ocorrem resultados bastante diferenciados no que se refere ao nível de desenvolvimento econômico alcançado. A resposta estaria nas trajetórias distintas de construção institucional, já que há arranjos que incentivam os atores a produzir e inovar, enquanto outros estimulam ações improdutivas e parasitárias. Nesse sentido procuramos mostrar que as instituições construídas ao longo do tempo na Venezuela, essencialmente, incentivaram a lógica rentista entre os atores sociais, dos empresários aos sindicatos. Para isso nos utilizamos dos conceitos de lock in e, principalmente, de path dependence que nos permitem qualificar a dimensão histórica do problema, mostrando como ao longo do tempo os atores adotaram estratégias e ações que se reforçaram e bloquearam qualquer mudança, já que os setores com maior poder de barganha dificultaram qualquer alteração nos arranjos existentes na medida em que foram favorecidos por eles. Inclusive, a principal fonte de path dependence são os rendimentos crescentes dos arranjos existentes, o que, no caso da Venezuela, torna muito difícil qualquer alteração no modelo rentista. O trabalho procura mostrar que, mesmo com Chávez que propõe um socialismo sob base rentista, ou seja, mantém o modelo ainda... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The purpose of this work is to analyze how the government of Hugo Chávez has proposed to overhaul the Venezuelan State, through a process of drafting a new constitution and based upon a nationalistic and Bolivarian rhetoric, which sought to radically transform the economic structure, but was limited by the strength of the permanence of the institutional legacy of the country which, in turn, was built up on the oil dependence and on a rentier logic basis. For this, we recur to authors that work with the institutional dimension of economic development and care in explaining why in the face of similar material conditions, distinct results regarding the level of accomplished economic development are achieved. The answer would lie in different paths of institutional construction, as there are arrangements that encourage the actors to produce and innovate, while others stimulate unproductive and predatory actions. We try to show that the institutions built over time in Venezuela, basically encouraged the rentier logic among the social actors, from the entrepreneurs to the work unions. For this we use the concept of lock-in, and especially the concept of path dependence. Both allow us to classify the historical dimension of the problem, showing how actors have continuously adopted strategies and actions which reinforced and blocked any possibility of changes, since the sectors with greater bargaining power hampered any modification in existing arrangements as they were benefited by them. Also the main source of path dependence are increasing returns of existing arrangements, which in the case of Venezuela, make any change in the rentier model rather difficult. This work shows that, even taking into account that Chávez proposes a rentier-based socialism, what means the model is kept even though nationalized, it still repeats what was done in previous decades, albeit with a social... (Complete abstract click electronic access below) / Doutor

Bakgrund: Heroin är en opiat ursprungen från opiumvallmon och är starkt förknippad med beroende och död. När heroin och andra kortverkande opiater binder in till μ-opioidreceptorer i hjärnan sker en ökad frisättning av signalsubstansen dopamin och en stark känsla av eufori infinner sig. Vid upprepat intag sker förändringar i hjärnan; belöningseffekten minskar medan antibelöningseffekterna ökar och cravings och abstinensymptom blir allt tydligare vid frånvaro av drogen. Vid läkemedelsassisterad rehabilitering vid opiatberoende (LARO) används förutom psykosocial behandling även långverkande opioider såsom opioidagonisten metadon och den partiella opioidagonisten buprenorfin, för att återställa homeostasen och reducera cravings och abstinenssymptom som opioidberoendet har skapat. Metadon är effektivt vid beroendebehandling men dess risker begränsar dess användning. Buprenorfin har lägre överdospotential men eventuellt sämre effekt än metadon. Syfte: Syftet med denna litteraturstudie var att undersöka skillnad i effekt mellan buprenorfinpreparat och metadon vid behandling av opioidberoende. Metod: Arbetet är en litteraturstudie baserat på fem vetenskapliga studier vilka har erhållits via sökning i PubMed samt Cochrane Library. De aspekter som avhandlats är; fullföljande och retention av behandling, samtidigt sidomissbruk av opiater samt allvarliga incidenter och biverkningar. Resultat: De inkluderade studierna i denna litteraturstudie visade att metadon är bättre på att bevara patienter i behandling medan buprenorfin mer effektivt kan minska sidomissbruket av opiater. Ju högre doser som användes, desto fler deltagare stannade kvar i behandling och desto färre urinprover rapporterades positiva för sidomissbruk av opiater. Få allvarliga incidenter rapporterades från studierna. Slutsats: Både metadon och buprenorfinpreparaten har sina för- och nackdelar.  Då behandling med metadon tidigare bevisats vara mer riskfyllt bör buprenorfinpreparaten utgöra förstahandsval, men vid otillräcklig effekt bör byte till metadon ske. Detta överrensstämmer med riktlinjerna i Sverige idag. Dock tycks det finnas anledning att i framtida studier undersöka dos-effekt-samband för både dessa preparat, samt också att fokusera på den initiala fasen vid behandling med buprenorfin. / Background: Heroin is an opiate from the opium poppy which is strongly associated with dependence, overdose and death. When heroin and other opiates binds to the μ-opioid receptors located in the brain, dopamine is released from the ventral tegmental area and a strong feeling of euphoria arises. Continuous intake of opioids cause changes in the brain and the feeling of euphoria will be less distinct during drug intake. Instead, cravings and abstinence, will be more distinctive in absence of the drug and causes drug-abusers to continue to use the drug. The cravings and abstinence is due to an overactive HPA-axis and amygdala. This overactivity can be reduced by treatment with long lasting opioids that is used in treatment of opioid dependence. The development of opioid maintenance treatment started in the US during the early 1960s. A few years later, opioid dependent people could join the first opioid maintenance treatment program in Uppsala, Sweden. The opioid maintenance treatment involves both pharmacological and psychosocial treatment. There are two main substances available for opioid maintenance treatment in Sweden: methadone, a full μ-opioid receptor agonist and buprenorphine, a partial μ-opioid receptor agonist. Methadone has been proven to be very efficacious treating opioid dependence. However, the risk of overdose leading to respiratory depression, limits its usefulness. Buprenorphine on the other hand, has a lower risk of toxicity but may not have same efficacy as methadone. Aim: The purpose of this literature study is to examine the efficacy of buprenorphine versus methadone among patients in opioid maintenance treatment. Methods: Five different randomized, controlled trials were selected from PubMed and The Cochrane Library to be included in this literature study. To limit this degree project, four variables was selected: completion and retention in treatment, use of illicit opiates during treatment and adverse events associated with treatment medication. Results: According to the findings in the five studies, methadone can be considered as a better option than buprenorphine when it comes to retaining participants in treatment. However, buprenorphine is somewhat more effective reducing the illicit use of opiates. When both methadone and buprenorphine were used in higher doses, more participants stayed in treatment. Also, higher doses were associated with a lower portion of urine samples positive for illicit opiates. Few adverse events were documented from the studies. Conclusion: Both methadone and buprenorphine have advantages and disadvantages. Since treatment with methadone is more perilous, buprenorphine should be considered as first-line treatment. But if the clinical effect remains insufficient, a transition to methadone treatment should occur, all according to the guidelines of opioid maintenance treatment in Sweden. However, future studies should consider evaluating the relationship between dose and effect of buprenorphine and possibly also methadone. Furthermore, more focus should be added on the initiation phase of treatment with buprenorphine.

Esta tese investiga as mudanças ocorridas nas políticas sobre drogas no Brasil e em Portugal na última década do século XX e na primeira do século XXI. O argumento central, tomado em parte dos debates existentes entre as vertentes neoinstitucionais, é que tais mudanças só podem ser interpretadas a partir do conhecimento a respeito das trajetórias históricas das políticas e sua relação com o contexto internacional mais amplo no qual estão inseridas. Desta forma, construiu-se uma narrativa a respeito das mudanças em um processo indutivo baseado em investigação empírica que se articula em torno do conceito de dependência da trajetória. Nesse sentido, a ideia central da tese é que as diferentes naturezas das mudanças nas políticas analisadas podem ser compreendidas a partir da sua contextualização histórica e da importância dos efeitos que as escolhas e decisões tomadas em um dado momento têm no desenvolvimento posterior das políticas. / This thesis investigates the changes ocurred in the drug policies in Brazil and in Portugal in the last decade of the XXth century and in the first decade of the XXIst century. The central argument, taken in part of the existing debates within the neoinstitucionalist approaches, is that such changes can only be interpreted based on the knowledge regarding the historical trajectories of the policies and its relation with the broader international context in which they are imbedded. This way, a narrative was built concerning the changes on drug policies in these both countries, in an inductive process, grounded on empirical research that articulates itself around the concept of path dependence. In this sense, the central idea of the thesis is that the different natures of the changes in the analysed policies can be understood based on its historical contextualization and the importance of the effects that the choices and decisions taken in a certain moment have in the ulterior development of the policies.