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Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs), two groups of structurally related chlorinated aromatic hydrocarbons, are of high concern due to their global distribution and extreme toxicity. Since they occur at very low levels, their analysis is complex, challenging and hence there is a need for efficient, reliable and rapid alternative analytical methods. Developing such methods was the aim of the project this thesis is based upon. During the first years of the project the focus was on the first parts of the analytical chain (extraction and clean-up). A selective pressurized liquid extraction (SPLE) procedure was developed, involving in-cell clean-up to remove bulk co-extracted matrix components from sample extracts. It was further streamlined by employing a modular pressurized liquid extraction (M-PLE) system, which simultaneously extracts, cleans up and isolates planar PCDD/Fs in a single step. Both methods were validated using a wide range of soil, sediment and sludge reference materials. Using dichloromethane/n-heptane (DCM/Hp; 1/1, v/v) as a solvent, results statistically equivalent to or higher than the reference values were obtained, while an alternative, less harmful non-chlorinated solvent mixture - diethyl ether/n-heptane (DEE/Hp; 1/2, v/v) – yielded data equivalent to those values. Later, the focus of the work shifted to the final instrumental analysis. Six gas chromatography (GC) phases were evaluated with respect to their chromatographic separation of not just the 17 most toxic congeners (2,3,7,8-substituted PCDD/Fs), but all 136 tetra- to octaCDD/Fs. Three novel ionic liquid columns performed much better than previously tested commercially available columns. Supelco SLB-IL61 offered the best overall performance, successfully resolving 106 out of the 136 compounds, and 16 out of the 17 2,3,7,8-substituted PCDD/Fs. Another ionic liquid (SLB-IL111) column provided complementary separation. Together, the two columns separated 128 congeners. The work also included characterization of 22 GC columns’ selectivity and solute-stationary phase interactions. The selectivities were mapped using Principal Component Analysis (PCA) of all 136 PCDD/F’s retention times on the columns, while the interactions were probed by analyzing both the retention times and the substances’ physicochemical properties.

Submitted by MARILIA PEREIRA (mariliappereira@gmail.com) on 2017-08-14T16:43:48Z No. of bitstreams: 1 dissertacao - versão final.pdf: 1038846 bytes, checksum: 3a5db7928b3eb4397e660b4cb7c98b09 (MD5) / Approved for entry into archive by Patricia Barroso (pbarroso@ufba.br) on 2017-08-16T00:38:52Z (GMT) No. of bitstreams: 1 dissertacao - versão final.pdf: 1038846 bytes, checksum: 3a5db7928b3eb4397e660b4cb7c98b09 (MD5) / Made available in DSpace on 2017-08-16T00:38:52Z (GMT). No. of bitstreams: 1 dissertacao - versão final.pdf: 1038846 bytes, checksum: 3a5db7928b3eb4397e660b4cb7c98b09 (MD5) / FAPESB - Fundação de Amparo à Pesquisa do Estado da Bahia / Esta dissertação traz como tema central o ensino de português como língua de herança em uma escola bilíngue na Alemanha e reflete sobre o ensino de português nesse contexto. O objetivo desta pesquisa visa compreender qual a relação que os aprendizes têm com a sua língua de herança, como ela se desenvolve e como as representações da cultura e da língua portuguesa são promovidas e valorizadas em uma escola bilíngue na Alemanha. A pesquisa de natureza qualitativa, de cunho etnográfico, gerou os dados a partir da observação participante das aulas de português, das entrevistas e dos questionários preenchidos pelos alunos. Os principais resultados apontam que, embora a maior parte dos alunos tenha como objetivo na aprendizagem da sua língua de herança estreitar laços familiares, o desenvolvimento das habilidades e competências linguísticas dos alunos ampliam a percepção da língua aos fatores sociais e econômicos, a globalização e a oportunidade no mercado de trabalho. Ademais, a convivência dos alunos com colegas e professores que fazem parte de diferentes culturas da comunidade lusófona mostrou que alunos e professores da referida escola são capazes de reconhecer diferenças e semelhanças entre as variedades da língua, sem, contudo, influenciar na variedade falada em casa. Essas diferenças foram avaliadas positivamente pelos alunos. Tal realidade permite olhar para o ensino de língua de herança a partir de uma abordagem que considere a língua portuguesa como língua pluricêntrica, auxiliando no desenvolvimento da proficiência linguística dos aprendizes em contexto de diáspora. No entanto, é preciso ainda criar estratégias para ampliar a utilização de materiais didáticos que inclua a diversidade dos países de língua portuguesa, principalmente relacionado aos PALOP – Países Africanos de Língua Oficial Portuguesa -, haja vista a vasta literatura de autores africanos. / This dissertation brings as a central theme the teaching of Portuguese as a heritage language in a bilingual school in Germany and reflects about the teaching of Portuguese in this context. This research is aimed at understanding the relationship that the learners have with their heritage language, how it develops and how representations of culture and the Portuguese language are promoted and valued in a bilingual school in Germany.The research of qualitative nature, ethnographic, generated the data from the participant observation during Portuguese classes and through the interviews and the questionnaires carried out with the researched subjects.The main results show that, although the majority of students have as a goal in learning heritage language to strengthen family ties, the extension of the skills and abilities causes other reasons to emerge when linked to learning, such as social and economic factors, globalization and the future profession. In addition, the contact of students with classmates and teachers from different Portuguese-speaking countries showed that the subjects of this school are able to recognize differences and similarities between the varieties of the language, without necessarily excerting an influence on the variety spoken at home. The results also revealed that the possibility of having colleagues and teachers who speak different varieties of Portuguese was evaluated as positive by the students.This reality allows us to look at the teaching of heritage language from an approach that considers Portuguese as a pluricentric language, assisting in the development of the linguistic proficiency of learners in a diaspora context. However, it is still necessary to create awareness strategies to increase the use of teaching materials that bring more diversity to the Portuguese-speaking countries, mainly related to the PALOP, due to the vast literature of African, Brazilian and Portuguese authors.

Este trabalho apresenta uma análise baseada no confronto entre dois instrumentos: o livro didático para ensino de Português Língua Estrangeira (PLE) e o exame de proficiência Celpe-Bras. Tomamos como base a teoria bakhtiniana para analisar não só a composição dos livros e seus recursos didáticos, com foco nas atividades que promovem a leitura e a produção de textos, mas também a constituição do Exame Celpe-Bras como um gênero discursivo. Entendemos que a língua, como a materialização de enunciados individuais, elaborados a partir de uma finalidade específica, num determinado contexto social e de acordo com padrões composicionais definidos histórica e socialmente, deva ser ensinada a partir de amostras autênticas. Nosso principal objetivo é verificar se há convergências entre as propostas dos livros e as do exame, que se baseia num conjunto de tarefas a que os candidatos se submetem, a fim de comprovar sua competência comunicativa na língua-alvo. Considerando-se o efeito retroativo dos exames de alta relevância, nosso objetivo é verificar se esse efeito é observável nos livros que fazem parte do corpus desta pesquisa, para propor alterações que possam aproximar ambos os objetos, o de ensino e o avaliativo, com vistas a promover o aprimoramento constante das obras didáticas. Entendemos que essa atualização pode aproximar o aprendiz da realidade do falante nativo, capacitando-o para uma leitura discursiva que vá além da aquisição do vocabulário e de estruturas gramaticais. Nossa escolha pelo Exame se deve à crescente expansão do número de inscritos e de postos de aplicação do Celpe-Bras, o que nos faz avaliá-lo como um instrumento que colabora para o fortalecimento da identidade brasileira, que se dá pela representatividade da língua portuguesa ao redor do mundo. / This thesis results from a comparative analysis of two instruments: course books for teaching PLE and the Celpe-Bras proficiency exam. We have adopted the bakhtinian theory to analyze not only the composition of the books and their teaching resources, with a focus on activities that promote reading and writing, but also the features of Celpe-Bras as a discourse genre. We understand that language, as the embodiment of individual utterances to meet a specific purpose in a particular social context, according to conventions that have been historically and socially established, should be taught from authentic samples. Our main goal is to look for similarities between the proposals in the books and the exam, which is based on a set of tasks that test takers are required to complete in order to prove their communicative competence in the target language. Considering the washback effect of high-stakes exams, our goal is to check whether this effect can be perceived in the books that are part of the corpus in this research in order to recommend changes that might approximate teaching and evaluation goals, with a view to promoting continued improvements in course books. We understand that such updating can bring learners closer to the experience of native speakers, thus enabling them to read discourse in ways that go beyond the acquisition of vocabulary and grammatical structures. Our choice for the exam is due to the growing number of candidates and centers where Celpe-Bras can be taken, which makes us consider it a tool that contributes to the strengthening of the Brazilian identity, which results from the importance of the Portuguese language around the world.

Neste estudo, analisou-se o tratamento dado à morfologia verbal do português em três tipos de obras de referência - um estudo de lingüística teórica; nove gramáticas de português, e os verbetes de terminações verbais de um dicionário -, na tentativa de: tornar a descrição mattosiana mais clara para a manipulação didática; verificar em que medida as gramáticas se beneficiam dessa análise; estabelecer possíveis razões para a defectividade em português, e atribuir uma classificação para os verbos com alternância vocálica, baseada no levantamento quantitativo desses verbos. Assim, a morfologia verbal foi examinada em três textos de Câmara Jr. (1975; 1972; 1970); duas gramáticas de português voltadas para falantes de português como língua materna (Bechara, 1999; Cunha; Cintra, 1985) e em sete gramáticas voltadas para falantes de português como língua estrangeira (Hutchinson; Lloyd, 2002; Perini, 2002; Masip, 2000; Abreu; Murteira, 1998; Gärtner 1998; Teyssier, 1984; Vázquez Cuesta; Mendes da Luz, 1980). Os resultados da pesquisa mostram que a descrição mattosiana está no bojo de exposição da morfologia das duas primeiras gramáticas, mas poderia ser mais explorada na exposição didática. O levantamento dos verbos defectivos em Bechara (1999); Cunha; Cintra (1985) permitiu verificar relação entre a defectividade verbal e uma possível alternância vocálica nos verbos de terceira conjugação. Apesar da descrição pouco econômica, o estabelecimento de verbetes de Houaiss; Villar (2001a; 2001b) favoreceu o levantamento quantitativo dos verbos com alternância vocálica, fazendo ver que o fenômeno ocorre na maioria dos verbos com vogais radicais /e/ e /o/ das três conjugações. / In this study, the treatment given to the verb Portuguese morphology was analyzed in three types of reference books - theoretical linguistic study; nine grammar books in Portuguese and the dictionary entries of verb endings -, in the attempt of: making clearer Joaquim Mattoso Câmara Jr. description for didactic usage; of verifying to what extent the grammar books take advantage of this analysis; of establishing possible reasons for the defectiveness in Portuguese and of classifying the verbs with vowel variation based on these verbs\' quantitative survey. This way the verb morphology was examined in three Câmara Jr. texts (1975; 1972; 1970); two Portuguese grammar books directed to Portuguese learners viewing this language as a mother-tongue (1975; 1972; 1970); and in seven grammar books directed to Portuguese learners viewing it as a foreign language. (1975; 1972; 1970). The results of this study reveal that Joaquim Mattoso Câmara Jr. description is in the core of the morphology exposure in the two former grammar books, but that it also could be better exploited in the didactic usage. The defective verbs survey in Bechara (1999, 1975); Cunha; Cintra (1985) made it possible to verify the relation between the verb defectiveness and a probable vowel variation in the third inflection verbs. Despite a brief description, the entries\'s setting found in Houaiss; Villar (2001a; 2001b) made it possible the quantitative survey of verbs with vowel variation showing that the phenomenon takes place in most part of verbs with root vowels /e/ and /o/ in the three inflections.

Este trabalho apresenta uma análise baseada no confronto entre dois instrumentos: o livro didático para ensino de Português Língua Estrangeira (PLE) e o exame de proficiência Celpe-Bras. Tomamos como base a teoria bakhtiniana para analisar não só a composição dos livros e seus recursos didáticos, com foco nas atividades que promovem a leitura e a produção de textos, mas também a constituição do Exame Celpe-Bras como um gênero discursivo. Entendemos que a língua, como a materialização de enunciados individuais, elaborados a partir de uma finalidade específica, num determinado contexto social e de acordo com padrões composicionais definidos histórica e socialmente, deva ser ensinada a partir de amostras autênticas. Nosso principal objetivo é verificar se há convergências entre as propostas dos livros e as do exame, que se baseia num conjunto de tarefas a que os candidatos se submetem, a fim de comprovar sua competência comunicativa na língua-alvo. Considerando-se o efeito retroativo dos exames de alta relevância, nosso objetivo é verificar se esse efeito é observável nos livros que fazem parte do corpus desta pesquisa, para propor alterações que possam aproximar ambos os objetos, o de ensino e o avaliativo, com vistas a promover o aprimoramento constante das obras didáticas. Entendemos que essa atualização pode aproximar o aprendiz da realidade do falante nativo, capacitando-o para uma leitura discursiva que vá além da aquisição do vocabulário e de estruturas gramaticais. Nossa escolha pelo Exame se deve à crescente expansão do número de inscritos e de postos de aplicação do Celpe-Bras, o que nos faz avaliá-lo como um instrumento que colabora para o fortalecimento da identidade brasileira, que se dá pela representatividade da língua portuguesa ao redor do mundo. / This thesis results from a comparative analysis of two instruments: course books for teaching PLE and the Celpe-Bras proficiency exam. We have adopted the bakhtinian theory to analyze not only the composition of the books and their teaching resources, with a focus on activities that promote reading and writing, but also the features of Celpe-Bras as a discourse genre. We understand that language, as the embodiment of individual utterances to meet a specific purpose in a particular social context, according to conventions that have been historically and socially established, should be taught from authentic samples. Our main goal is to look for similarities between the proposals in the books and the exam, which is based on a set of tasks that test takers are required to complete in order to prove their communicative competence in the target language. Considering the washback effect of high-stakes exams, our goal is to check whether this effect can be perceived in the books that are part of the corpus in this research in order to recommend changes that might approximate teaching and evaluation goals, with a view to promoting continued improvements in course books. We understand that such updating can bring learners closer to the experience of native speakers, thus enabling them to read discourse in ways that go beyond the acquisition of vocabulary and grammatical structures. Our choice for the exam is due to the growing number of candidates and centers where Celpe-Bras can be taken, which makes us consider it a tool that contributes to the strengthening of the Brazilian identity, which results from the importance of the Portuguese language around the world.

This thesis work aims at a better understanding of magneto-optical properties of dilute nitrides and II-VI diluted magnetic semiconductor quantum structures. The thesis is divided into two parts. The first part gives an introduction of the research fields, together with a brief summary of the scientific results included in the thesis. The second part consists of seven scientific articles that present the main findings of the thesis work. Below is a short summary of the thesis. Dilute nitrides have been of great scientific interest since their development in the early 1990s, because of their unusual fundamental physical properties as well as their potential for device applications. Incorporation of a small amount of N in conventional Ga(In)As or Ga(In)P semiconductors leads to dramatic modifications in both electronic and optical properties of the materials. This makes the dilute nitrides ideally suited for novel optoelectronic devices such as light emitting devices for fiber-optic communications, highly efficient visible light emitting devices, multi-junction solar cells, etc. In addition, diluted nitrides open a window for combining Si-based electronics with III-V compounds-based optoelectronics on Si wafers, promising for novel optoelectronic integrated circuits. Full exploration and optimization of this new material system in device applications requires a detailed understanding of their physical properties. Papers I and II report detailed studies of effects of post-growth rapid thermal annealing (RTA) and growth conditions (i.e. presence of N ions, N2 flow, growth temperature and In alloying) on the formation of grown-in defects in Ga(In)NP. High N2 flow and bombardment of impinging N ions on grown sample surface is found to facilitate formation of defects, such as Ga interstitial (Gai) related defects, revealed by optically detected magnetic resonance (ODMR). These defects act as competing carrier recombination centers, which efficiently decrease photoluminescence (PL) intensity. Incorporation of a small amount of In (e.g. 5.1%) in GaNP seems to play a minor role in the formation of the defects. In GaInNP with 45% of In, on the other hand, the defects were found to be abundant. Effect of RTA on the defects is found to depend on initial configurations of Gai related defects formed during the growth. In Paper III, the first identification of an interfacial defect at a heterojunction between two semiconductors (i.e. GaP/GaNP) is presented. The interface nature of the defect is clearly manifested by the observation of ODMR lines originating from only two out of four equivalent <111> orientations. Based on its resolved hyperfine interaction between an unpaired electronic spin (S=1/2) and a nuclear spin (I=1/2), the defect is concluded to involve a P atom at its core with a defect/impurity partner along a <111> direction. Defect formation is shown to be facilitated by N ion bombardment. In Paper IV, the effects of post-growth hydrogenation on the efficiency of the nonradiative (NR) recombination centers in GaNP are studied. Based on the ODMR results, incorporation of H is found to increase the efficiency of the NR recombination via defects such as Ga interstitials. In Paper V, we report on our results from a systematic study of layered structures containing an InGaNAs/GaAs quantum well, by the optically detected cyclotron resonance (ODCR) technique. By monitoring PL emissions from various layers, the predominant ODCR peak is shown to be related to electrons in GaAs/AlAs superlattices. This demonstrates the role of the SL as an escape route for the carriers confined within the InGaNAs/GaAs single quantum well. The last two papers are within a relatively new field of spintronics which utilizes not only the charge (as in conventional electronics) but also the quantum mechanical property of spin of the electron. Spintronics offers a pathway towards integration of information storage, processing and communications into a single technology. Spintronics also promises advantages over conventional charge-based electronics since spin can be manipulated on a much shorter time scale and at lower cost of energy. Success of semiconductor-based spintronics relies on our ability to inject spin polarized electrons or holes into semiconductors, spin transport with minimum loss and reliable spin detection. In Papers VI and VII, we study the efficiency and mechanism for carrier/exciton and spin injection from a diluted magnetic semiconductor (DMS) ZnMnSe quantum well into nonmagnetic CdSe quantum dots (QD’s) by means of spin-polarized magneto PL combined with tunable laser spectroscopy. By means of a detailed rate equation analysis presented in Paper VI, the injected spin polarization is deduced to be about 32%, decreasing from 100% before the injection. The observed spin loss is shown to occur during the spin injection process. In Paper VII, we present evidence that energy transfer is the dominant mechanism for carrier/exciton injection from the DMS to the QD’s. This is based on the fact that carrier/exciton injection efficiency is independent of the width of the ZnSe tunneling barrier inserted between the DMS and QD’s. In sharp contrast, spin injection efficiency is found to be largely suppressed in the structures with wide barriers, pointing towards increasing spin loss.

This study compares four recently developed decline curve methods and the traditional Arps or Fetkovich approach. The four methods which are empirically formulated for shale and tight gas wells are: 1. Power Law Exponential Decline (PLE). 2. Stretched Exponential Decline (SEPD). 3. Duong Method. 4. Logistic Growth Model (LGM). Each method has different tuning parameters and equation forms. The main objective of this work is to determine the best method(s) in terms of Estimated Ultimate Recovery (EUR) accuracy, goodness of fit, and ease of matching. In addition, these methods are compared against each other at different production times in order to understand the effect of production time on forecasts. As a part of validation process, all methods are benchmarked against simulation. This study compares the decline methods to four simulation cases which represent the common shale declines observed in the field. Shale wells, which are completed with horizontal wells and multiple traverse highly-conductive hydraulic fractures, exhibit long transient linear flow. Based on certain models, linear flow is preceded by bilinear flow if natural fractures are present. In addition to this, linear flow is succeeded by Boundary Dominated Flow (BDF) decline when pressure wave reaches boundary. This means four declines are possible, hence four simulation cases are required for comparison. To facilitate automatic data fitting, a non-linear regression program was developed using excel VBA. The program optimizes the Least-Square (LS) objective function to find the best fit. The used optimization algorithm is the Levenberg-Marquardt Algorithm (LMA) and it is used because of its robustness and ease of use. This work shows that all methods forecast different EURs and some fit certain simulation cases better than others. In addition, no method can forecast EUR accurately without reaching BDF. Using this work, engineers can choose the best method to forecast EUR after identifying the simulation case that is most analogous to their field wells. The VBA program and the matching procedure presented here can help engineers automate these methods into their forecasting sheets.

Made available in DSpace on 2016-06-02T20:24:59Z (GMT). No. of bitstreams: 1 DissRMRS.pdf: 887881 bytes, checksum: 41ba18fdae05f3aa71ad0e6f29665a18 (MD5) Previous issue date: 2006-12-11 / The washback effect of an assessment is a redirecting element not only on teaching and learning process, but on most student s and teacher s actions, manners, beliefs and perceptions inside and outside the classroom, influencing the values in a society in which a certain educational system is used. For this reason, investigating the impacts of an assessment means taking into consideration the possible variables that go through the teaching/learning context, present in the learning culture of an individual. The proficiency test in Portuguese Language Celpe-Bras, developed and applied by Brazil Education Ministry, has a different proposal from the adopted one in other proficiency tests. The Celpe-Bras, a communicative approach test, assesses proficiency through tasks that look like real communication situations. The aim of this work is to analyze the effects of this test in the learning culture of four applicants to the exam, showing the possible changes observed in their beliefs, actions, manners and perceptions about the test in three different moments: before the first contact with the exam, after the first contact with it (preparation phase) and after its carrying out. The data of this research are constituted by thirteen interviews conducted with selected applicants. From these interviews, twenty two excerpts were used in the analysis. Through the results, we expect to contribute with a relevant analysis about the learning culture of the applicants who have subscribed to this exam for the first time. / O efeito retroativo de uma avaliação é um elemento redirecionador, não apenas no processo de ensino/aprendizagem, mas também na maioria das ações, maneiras, crenças e percepções de alunos e de professores dentro e fora da sala de aula, que influencia nos valores de uma certa sociedade, na qual um determinado sistema educacional é usado. Por isso, investigar os impactos de uma avaliação significa levar em consideração as possíveis variáveis que permeiam o contexto de ensino/aprendizagem, presentes na cultura de aprender do indivíduo. O Certificado de Proficiência em Língua Portuguesa para Estrangeiros, Celpe-Bras, desenvolvido e aplicado pelo Ministério da Educação do Brasil, apresenta uma proposta de avaliação diferente da adotada por outros exames de proficiência. De natureza comunicativa, o Celpe-Bras avalia a proficiência na língua portuguesa por meio de tarefas que se assemelham a situações reais de comunicação. O objetivo deste trabalho é analisar os impactos desse teste na cultura de aprender de quatro candidatos ao exame, apontando as possíveis mudanças observadas em suas crenças, ações, maneiras e percepções sobre o teste em três diferentes momentos: antes do primeiro contato com o exame, após o primeiro contato com o exame (fase de preparação) e após a realização do mesmo. O corpus desta pesquisa é constituído de treze entrevistas com os candidatos selecionados, das quais foram retirados vinte e dois excertos para análise. Por meio dos resultados, espera-se contribuir para uma análise relevante sobre a cultura de aprender de candidatos que se submetem a essa avaliação pela primeira vez.

Made available in DSpace on 2015-05-14T12:42:40Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 5306084 bytes, checksum: 0029bc746fe114ecca5d52e0b7c2a635 (MD5) Previous issue date: 2011-03-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Throughout two years (2008-2009), at the Federal University of Paraíba (UFPB), I tried to lead students from other countries to learn Portuguese as a Foreign Language (PFL) in a situated and contextualized way. From this perspective, the reflection upon the social uses of textual genres has become crucial, since, as is well known, we use genres in order to act in society. The theoretical contributions of Bronckart (1985, 1996, 1999, 2006, 2008) served as a foundation in this action research, in order to bring the students to act communicatively, that is, through language. Therefore, my research questions are the following: do the literacy practices in PFL influence the way in which students position themselves when developing certain textual genres? What are the consequences or impacts of these practices in the way they position themselves in written texts? Do marks of enunciation, more precisely, the modalizations used by students, favor the achievement of the objectives in mind? My hypothesis revolved around the belief that during the development of written textual production, students use enunciative mechanisms, which, on guiding the reader´s interpretation, constitute key elements for achieving the goals which motivated the students to construct such texts. Dwelling on the analysis of two textual genres, namely, educational memories and letters (personal and addressed to public bodies), a comparison is made between texts written by students of different levels (basic/advanced), so as to find out whether the texts written by elementary level students highlight the development of these practices in a significant way, as well as between students from the same level (basic/basic, advanced/advanced), so as to comprehend if the relevance of these practices relate to an isolated case, or whether, in fact, they were reaching the majority of the students from the same level. The analyzed genres reveal that students generally knew how to deal with words, with good levels of persuasion, in view of the objectives, as well as with the interlocutor in mind. Although students, especially those from more advanced levels, already have well-developed literacy practices in their first language, the mere fact of having participated in a learning process that encompassed literacy practices enabled them to further develop certain skills in another language, in a new culture. / Ao longo de dois anos (2008-2009), na Universidade Federal da Paraíba (UFPB), procuramos levar estudantes provenientes de outros países a aprenderem o Português Língua Estrangeira (PLE) de maneira situada, contextualizada. Nessa perspectiva, a reflexão acerca dos usos sociais dos gêneros de texto tornou-se fundamental, uma vez que, conforme já é bem sabido, utilizamos os gêneros para agir em sociedade. Os aportes teóricos de Bronckart (1985, 1996, 1999, 2006, 2008) serviram-nos de base para o encaminhamento de nossa pesquisa-ação, tendo em vista levar o estudante a agir comunicativamente, ou seja, por meio da linguagem. Assim, tivemos como um de nossos objetivos o interesse de responder à seguinte questão: as práticas de letramento em PLE influenciam no modo como os estudantes se posicionam ao elaborarem determinados gêneros de textos ou quais os desdobramentos ou impactos dessas práticas no modo como se posicionam nos textos escritos? As marcas enunciativas, mais precisamente, as modalizações utilizadas pelos estudantes favorecem o alcance dos objetivos em mente? Nossa hipótese girou em torno do fato de crermos que, durante o desenvolvimento de produções textuais, neste caso, escritas, os estudantes utilizam mecanismos enunciativos, que, por orientarem a interpretação do leitor, acabam se configurando como elementos fundamentais para se atingir os objetivos que os motivaram a construir tais textos. Detendo-nos na análise de dois principais gêneros de texto, a saber, relatos ou memórias educativas e cartas (pessoais e endereçadas a instâncias públicas), ora comparamos textos elaborados por estudantes de níveis distintos (básico/avançado), para sabermos até que ponto os textos de estudantes do básico evidenciavam os desdobramentos de nossas práticas de maneira significativa, ora por estudantes de mesmo nível (básico/básico, avançado/avançado), para sabermos até que ponto a relevância dessas práticas estava relacionada a um caso isolado ou se, de fato, estavam atingindo a maioria dos estudantes de um mesmo nível. Os gêneros analisados revelam que os estudantes de modo geral souberam lidar com as palavras, apresentando, inclusive, bons níveis de persuasão, tendo em vista os objetivos propostos, assim como o interlocutor que se tinha em mente. Embora os estudantes, principalmente de níveis mais avançados, já terem bem desenvolvidas as práticas de letramento em sua língua materna, o simples fato de terem participado de um processo de aprendizagem que contemplasse práticas de letramento, possibilitou-lhes desenvolver ainda mais certas habilidades, em outra língua, em uma nova cultura.