The Arab spring has been called a social media revolution and social media have been given large importance and significant space in both academic discussions and analysis in the media. The main focus of this study was to examine whether social media have impacted the news reporting of the conflicts. A sample of articles from four different newspapers was examined, taken randomly from all relevant articles published on the newspapers websites between December 2010 and December 2013. A part of that sample was checked for news agency cable reliance and the entire sample were checked for material from social media. Three newspapers were found to rely heavily on news agency material. The New York Times was the exception, having only 4 percent of articles being based on news agency material. Social media material and quotes were found and were used in the report-ing in different ways, but only in 4 percent of articles. It was mainly used as a way to get protester commentary. Two of the included newspapers were China Daily and the New York Times. The differences between the respective reporting in these newspapers were also examined in yet an-other subsample consisting of 100 articles from each newspaper. Several differences be-tween the reporting were found, with China Daily for example presenting a framing more in favour of the government of Syria than the New York Times.

In this thesis, a new reactive session reconstruction method &#039 / Smart-SRA&#039 / is introduced. Web usage mining is a type of web mining, which exploits data mining techniques to discover valuable information from navigations of Web users. As in classical data mining, data processing and pattern discovery are the main issues in web usage mining. The first phase of the web usage mining is the data processing phase including session reconstruction. Session reconstruction is the most important task of web usage mining since it directly affects the quality of the extracted frequent patterns at the final step, significantly. Session reconstruction methods can be classified into two categories, namely &#039 / reactive&#039 / and &#039 / proactive&#039 / with respect to the data source and the data processing time. If the user requests are processed after the server handles them, this technique is called as &lsquo / reactive&rsquo / , while in &lsquo / proactive&rsquo / strategies this processing occurs during the interactive browsing of the web site. Smart-SRA is a reactive session reconstruction techique, which uses web log data and the site topology. In order to compare Smart-SRA with previous reactive methods, a web agent simulator has been developed. Our agent simulator models behavior of web users and generates web user navigations as well as the log data kept by the web server. In this way, the actual user sessions will be known and the successes of different techniques can be compared. In this thesis, it is shown that the sessions generated by Smart-SRA are more accurate than the sessions constructed by previous heuristics.

This thesis is a sociolinguistic study of Preterit and Present Perfect (PP) usage in contemporary and earlier Argentinian River Plate Spanish (ARPS). The data analyzed stem from a 244,034-word corpus collected for the purposes of the study, including contemporary casual conversation, sociolinguistic interviews, participant observation, written questionnaires, and newspapers spanning the 19th–21st centuries. / The study is motivated by previous claims that in Latin America the PP is restricted to contexts that extend into the present time, resembling Peninsular medieval and Renaissance usage (e.g. Lope Blanch 1972: 138; Harris 1982: 50; Squartini & Bertinetto 2000: 413). I challenge this proposal showing that (1) ARPS has undergone its own development, and (2) Latin American varieties do not represent earlier frozen developmental stages akin to earlier Peninsular Spanish. / Although low in overall frequency, the contemporary ARPS PP is used in experiential settings to express indefinite past (a vernacular use). Moreover, multivariate analysis of the contemporary oral data reveals that the ARPS PP is not aspectually restricted to repetitive and iterative contexts extending into speech time – contrary to Schwenter and Torres Cacoullos’ (2008) findings for contemporary oral Mexican Spanish. Indeed, the data show that the ARPS continuative PP is losing its link-to-present requirement. The ARPS PP also features minimally in resultative and continuative settings, supporting layering of old and new grammaticalizing structures (Bybee, Perkins & Pagliuca 1994: 21). Present relevance does not determine ARPS PP usage and is instead encoded through the Preterit and temporal adverbials (TAs). / Historically, the PP has dwindled in usage frequency since the 19th century and the Preterit has invaded the spaces erstwhile occupied by the PP. PP functions like result, continuity, current relevance, and hot news are currently fulfilled by the Preterit, in combination with TAs (TA + VERB-PRET). I argue that the TA + VERB-PRET construction has emerged as a periphrastic encoder of PP nuances, a development reminiscent of perfect periphrases in languages such as Yoruba and Karaboro (Niger-Congo) (Dahl 1985: 130). A contemporary example of this construction includes the widespread temporal marker ahí ‘at this point in time’ (lit. ‘there’) in combination with the Preterit to indicate temporal immediacy. / The contemporary ARPS PP is sociolinguistically constrained; men use it significantly more often than women. The PP is also employed by younger speakers, challenging the position that this form is on the verge of extinction (Kubarth 1992a: 565; Burgos 2004: 103). In contrast to the contention that the PP occurs more frequently in written media (e.g. De Kock 1989: 489; Squartini & Bertinetto 2000: 413), the contemporary oral and newspaper corpora show similar distributional tendencies. Only in the questionnaire is the PP used more readily in ways unattested in oral interaction (i.e. in current relevance and past perfective settings). ARPS ambivalent use of the PP represents the essence of the so-called “actuation problem”; that is, the contention that the process of linguistic change involves stimuli and constraints from both society and from the structure of language (Weinrech, Labov & Herzog 1968: 186).

Thesis (PhD)--Macquarie University, Division of Environmental & Life Sciences, Department of Biological Sciences, 2008. / Bibliography: p. 257-274. / Literature review -- General materials and methods -- Characterisation of strain collection -- Distribution of integrons and gene cassettes in pseudomonas -- Genomic context of pseudomonas integrons -- Evolutionary analysis of pseudomonas spp. integrons 199 -- Final discussion -- Appendix -- References. / Integrons associated with mobile genetic elements have played a central role in the emergence and spread of multiple antibiotic resistance in many pathogenic bacteria. However, the discovery of integrons in the chromosomes of diverse, non-pathogenic bacteria suggests that integrons have a broader role in bacterial evolution. The Pseudomonas stutzeri species complex is a well studied model for bacterial diversity. Members of the complex are genetically closely related, but sub-taxa are not able to be defined by exclusively shared sets of phenotypic characters. Rather, on the basis of total DNA:DNA similarity, Ps. stutzeri strains have been divided into 17 different groups (termed genomovars). Two Ps. stutzeri strains have been found to contain Chromosomal Integrons (CIs). This thesis involved exploration of the hypothesis that a CI was present in the common ancestor of the Ps. stutzeri species complex and assessed the impact of integrons on diversity across all Pseudomonads. The history and significance of integrons is discussed in Chapter 1 as part of a literature review, and general materials and methods are provided in Chapter 2. Chapters 3 - 6 comprise the sections in which data generated during my PhD project are presented. A comprehensive analysis of the relationships between the strains being analysed is presented in Chapter 3. In Chapter 4, results of PCR and hybridisation screening for integrons across the strain collection are presented. In Chapter 5 the recovery of additional integrons and in depth sequence analysis of the recovered integrons are described. Finally, Chapter 6 contains statistical analyses of integron-associated genes and Chapter 7 contains a final discussion the most significant findings. Twenty-three Pseudomonas spp. strains were screened for the presence of integrons. All but three were found to contain integron-like sequences; however, most integron sequences recovered contained inactivated core integrons. viii Despite having a chromosomal locus, integrons in Pseudomonas were found to have properties indicative of frequent horizontal transfer. Evidence was also obtained which suggests that integrons have been acquired at the same locus on multiple independent occasions. This has not been observed in other families of chromosomal integrons and suggests that the loci at which integrons in Pseudomonas are found are hotspots for recombination. / Mode of access: World Wide Web. / xiii, 274 p. ill

Thesis (Ph.D.)--University of Wollongong, 2004. / Typescript. Includes bibliographical references: leaf 106-117.

Thesis (MPhil)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: This study examined the effect of language typically used on social network sites such as Facebook (referred to here as “Facebook-speak”) on the written academic work of a selected group of high school learners. The general aims of the study were to determine the prevalence of access to Facebook and thus of exposure to Facebook-speak amongst high school learners, and to establish whether any evidence of Facebook-speak features are identified in the written academic work of these learners. Eighty-eight learners from an English-Afrikaans dual medium school in a middle class region in the Western Cape participated in the study. The participants included 44 Afrikaans medium learners and 44 English medium learners of which 51 were in grade 8 and 37 were in grade 9. Questionnaires were completed by the learner participants to determine frequency and volume of Facebook use and self-reported recognition of features of Facebook-speak. Learners also completed a written exercise attached to the questionnaires for the purposes of discovering what counts as Facebook-speak features. The specific features the study anticipated were (deliberate) spelling errors, unconventional punctuation features, over-punctuation, the exclusion of functional words, the excessive use of abbreviations and acronyms and the incorporation of emoticons in written academic work. Additional features identified were the nonconventional use of tenses and sentence structure. The study hypothesised that high exposure to Facebook-speak and limited exposure to formal academic writing have an effect on the academic work of the learners. I considered a claim that the effects of Facebook-speak would be traceable in the schoolwork of the learners. The study therefore compared the actual academic marks the learner participants achieved in one semester for two of their subjects, namely their First Additional Language and History, and related these marks to questionnaire data. I assumed that in the language subject there would be more attention to aspects of grammar and writing, so that the effects of Facebook-speak were more likely to be seen in their History – and also reflected in their marks, i.e. I assumed weak writing skills would be more evident in History than in a language subject, and that weaker writing correlates with poorer marks. Five teacher participants from the same school also completed questionnaires regarding the visible features of Facebook-speak in the learners written work. They commented on new digital literacies and their impact on learners written academic work in an open-ended question put to them in the questionnaire. The results of the study indicate that learner-participants are ardent users of the social utility Facebook and that socio- economic and racial variables do not factor significantly into Facebook accessibility. The learners believe that Facebook does not have any negative impact on their History work. The data I worked with pointed to the contrary. The History marks were in fact lower than the First Additional marks across both grades and all the classes. This could be attributed (at least in part) to a lack of dedicated attention to grammaticality and writing style in the History classroom and an emphasis on factual correctness instead. Although they did not believe Facebook-interaction translated into weaker marks, almost half of the learners stated that Facebook does indeed have an impact on their written work. In considering the possible relation between Facebook-speak and academic performance, the study found that the Afrikaans L1 learners achieved lower marks in both their First Additional language (their L2) and History in comparison to the English L1 learners using the same measures. This possibly indicates not only high exposure to Facebook-speak, but also limited exposure to standardised forms of Afrikaans as it is used in other genres. The written exercise completed by the learners accounted for the majority of data that substantiated the hypothesis that Facebook-speak impacts the written academic work of learners at school. The Afrikaans medium learners scored weaker marks than the English medium participants. The overall non-formal language features were significantly more in the exercises written by Afrikaans medium learners. The abundance of non-formal language features represented in the learner participants’ written work can be related to any of a number of variables. Negative perceptions among teachers and learners regarding multimodalities and digital literacies do not allow the development of curricula or learning materials which integrate such new literacies in the learning process. The reality that learners’ world is one where digital communication and short messaging is likely to increase rather than disappear, obliges a search for effective ways of incorporating such real world uses of language into educational structures in a thorough and integrative way. Until tried and tested methods have been achieved, traditional literacies appear not to be developing, while the notion of new literacies is still on the backburner in South African schools. / AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die uitwerking van tipiese sosialenetwerk-taal soos die van Facebook (sogenaamde Facebook-speak) op die geskrewe akademiese werk van ‘n uitgesoekte groep hoërskoolleerders. Die Algemene oogmerk van die studie was om die heersende toegang tot Facebook en dus die blootstelling aan Facebook-speak van die leerders te bepaal en om vas te stel of daar getuienis van kenmerkende Facebook- speak in die geskrewe akadiemiese werk van hierdie leerders is. Agt-en-tagtig leerders van ‘n Engels-Afrikaans dubbelmediumskool in ‘n middelklas-omgewing in die Wes-Kaap het aan die studie deelgeneem. Die deelnemers het ingesluit 44 Afrikaansmedium-leerders en 44 Engelsmedium-leerders. Hiervan was 51 in graad 8 en 37 in graad 9. Die leerder-deelnemers het vraelyste voltooi om aan te toon wat die frekwensie en omvang van hul Facebook-gebruik was. Hulle eie herkenning van aspekte van Facebook- speak is ook getoets. ‘n Geskrewe oefening is by die vraelys aangeheg sodat die leerders self kon aandui wat hulle as kenmerke van Facebook- speak beskou. Die spesifieke kenmerke wat die studie voorsien het, was (doelbewuste) spelfoute, onkonvensionele punktuasie, oorpunktuasie, die uitsluiting van funksionele woorde, die oormatige gebruik van afkortings en akronieme en die insluiting van ikone vir emosies (sg “smileys”) in geskrewe akademiese werk. Bykomstige kenmerke wat geidentifiseer is, was die onkonvensionele gebruik van grammatikale tydsaanduidings en sinstruktuur. Die studie het veronderstel dat die hoë blootstelling aan Facebook- speak en die beperkte blootstelling aan formele akademiese skryfwerk ‘n uitwerking op die akademiese werk van leerders sou hê. ‘n Aanspraak dat die uitwerking van Facebook-spraak naspeurbaar in die skoolwerk van leerders sou wees, is ondersoek. Die studie het dus die werklike akademiese punte van die leerders in een semester in twee van hul vakke, naamlik Eerste Addisionele Taal, en Geskiedenis, in verband gebring met die vraelys-data. Die ondersoeker het veronderstel dat in die taalvak daar meer aandag aan aspekte van grammatika en skryfwerk gegee sou word, sodat die uitwerking van Facebook-speak in Geskiedenis meer waarskynlik merkbaar sou wees en dus ook uit hulle punte vir die onderskeie vakke sou blyk. Die veronderstelling was dat swak skryfvaardighede duideliker na vore sou kom in Geskiedenis as in ‘n taalvak, en dat swakker taalvaardighede met laer punte sou korreleer. Vyf onderwyser-deelnemers van dieselfde skool het ook ‘n vraelys voltooi oor die sigbare kenmerke van Facebook- speak in die leerders se geskrewe werk. In ‘n oopvraag-afdeling van die vraelys het hulle ook kommentaar gelewer oor digitale geletterdheid en die impak daarvan op leerders se geskrewe akademiese werk. Die studie laat blyk dat die leerder-deelnemers ywerige gebruikers van die Facebook-diens is en dat sosio-ekonomiese en rasse-veranderlikes geen beduidende rol speel in Facebook-toegang nie. Die leerders meen dat Facebook geen negatiewe uitwerking op hul Geskiedenis-werk het nie. Die data dui egter op die teendeel. Die Geskiedenispunte was inderdaad laer as die Eerste Addisionele Taal-punte vir beide graad-groepe en al die klasse. Dit kan dalk deels toegeskryf word aan ‘n gebrek aan doelgerigte aandag aan grammatikaliteit en skryfstyl in die Geskiedenis-klaskamers en ‘n groter klem op feitelike korrektheid. Ofskoon die leerders gemeen het hulle Facebook-interaksie lei nie tot swakker punte nie, het byna die helfte van hulle beweer dat Facebook inderdaad ‘n uitwerking op hulle geskrewe werk het. By die oorweging van die moontlike verhouding tussen Facebook-speak en akademiese prestasie, bevind die studie dat die Afrikaans L1-leerders laer punte gekry het in beide hul Eerste Addisionele Taal (hulle L2) en Geskiedenis vergeleke met die Engels L1-leerders. Dit dui moontlik op ‘n hoë blootstelling aan Facebook- speak onder die Afrikaanse leerders, maar ook beperkte blootstelling aan gestandaardiseerde vorme van Afrikaans soos dit voorkom in ander genres. Die geskrewe oefening het die meeste data opgelewer ter ondersteuning van die hipotese dat Facebook- speak ‘n uitwerking het op die geskrewe akademiese werk van skoolleerders. Die Afrikaansmedium-leerders het laer punte gekry as hulle Engelsmedium eweknieë. Die oorheersende nie-formele taalkenmerke was beduidend meer aanwesig in die oefeninge wat deur die Afrikaansmedium leerders geskryf is. Die oormaat nie-formele taalkenmerke wat in die leerder-deelnemers se geskrewe werk voorkom kan met verskeie veranderlikes in verband gestel word. Negatiewe persepsies onder onderwysers en leerders rakends multimodaliteit en digitale geletterdheid laat waarskynlik nie toe vir ontwikkeling van kurrikula of leermateriaal wat aansluit by nuwe geletterdheidsvorme in die leerproses nie. Die werklikheid dat die leerder in ‘n wêreld leef waar digitale kommunikasie en kortboodskap-flitse waarskynlik eerder gaan toeneem as gaan verdwyn, maak dit belangrik dat daar gesoek word na doeltreffende maniere waarop sulke gebruike van taal in die regte wêreld deeglik in die onderwysstrukture geintegreer sal word. Terwyl beproefde en bewese metodes nog buite bereik is en tradisionele geletterdheid skynbaar nie ontwikkel nie, lyk dit asof die idee van nuwe geletterdhede in Suid-Afrikaanse skole nog net toekomsmusiek is.

Cette thèse a pour objet les opérations de portage foncier, dont on observe la multiplication en France depuis les années 2000. Ces initiatives regroupent différents types d'acteurs parmi lesquels les collectivités locales, les organisations professionnelles agricoles et les associations. Elles visent, par une acquisition foncière, à maîtriser l'usage agricole du foncier à long terme dans des espaces soumis à la pression urbaine, en sécurisant leur accès pour les agriculteurs. Des initiatives collectives comparables sont à l'œuvre dans les pays européens et d'Amérique du Nord (Land trusts, fiducies, coopératives, etc.), soulevant notamment les questions environnementales et d'orientation alternative de l'agriculture. En France, les opérations de portage foncier observées ont pour spécificités, d'une part d'impliquer des acteurs publics locaux, et d'autre part d'émerger face à la menace d'urbanisation. Pourtant l'action publique décentralisée dispose de nombreux outils pour la préservation du foncier agricole. Aussi, ce recours à l'acquisition foncière, envisagée désormais de manière non temporaire, interroge. Cette thèse s'intéresse aux modalités singulières qu'induisent les opérations de portage foncier dans la gouvernance des espaces agricoles. Elle combine trois analyses au niveau meso-économique des coordinations, au niveau micro-économique des transactions, et au niveau macro-économique des institutions. Ancrée dans l'économie institutionnelle, la démarche adoptée propose des focus depuis ces trois points de vue. Le premier consiste en une analyse de la construction de l'accord sur lequel reposent les opérations de portage foncier, entre des acteurs aux objectifs et légitimés variés. Il s'appuie sur le cadre de l'Economie des conventions. Le second s'intéresse à l'effet des opérations de portage foncier quant à la facilité d'accès à la terre pour les agriculteurs. Une grille d'analyse des coûts d'accès à l'usage est développée, utilisant notamment le concept de coûts de transaction. Le troisième focus est une réflexion sur les changements institutionnels introduits par les opérations de portage foncier, via une analyse historique du rapport usage-propriété en tant que formule institutionnelle. Cette thèse soutient que les négociations entre acteurs qui sont à l'origine des opérations de portage foncier abordent rarement la préservation de l'espace agricole face à l'urbanisation, indépendamment de son utilisation. Souvent le modèle agricole projeté est fondateur de la démarche, notamment sur la question du rapport entre agriculture et environnement. La maîtrise foncière proposée par le portage foncier induit malgré tout une nouvelle modalité d'accès à l'usage pour les agriculteurs, plus difficile à instaurer d'un point de vue organisationnel, mais plus sécurisante. Parallèlement, le droit de propriété privé revient en force dans le rapport propriété-usage qui en découle. Le droit de propriété était pourtant relativement inféodé à l'usage privé, pour l'intérêt public que ce dernier représente, depuis la moitié du 20ème siècle. Précisant peu les contours de l'intérêt général, l'action publique les laisse donc être déterminés au gré des dynamiques privées, au risque d'induire des inégalités territoriales. / This PhD dissertation focuses on land backing actions, which notably increase in France since the early 2000s. These initiatives include different types of stakeholders among local authorities, agricultural professional organizations and non-governmental organizations. By acquiring land, they aim to control long-term agricultural use in areas threatened by urbanization by securing farmers' access to land. Some comparable collective initiatives also occur in European and North-American countries (Land trusts, fiducies, cooperatives ...), particularly raising environment and alternative agriculture issues. The land backing actions observed in France are specific for two reasons: in one hand they involve local public authorities, and in the other hand they emerge facing the threat of urbanization. Yet the devolved public action has many available instruments for the preservation of agricultural land. Hence, the use of ownership, which is now considered in the long term, brings up questions. This PhD thesis addresses the singular modalities induced by land backing actions in the farmland governance. It combines three analyses at the coordinations meso-economic level, at the transactions micro-economic level, and at the institutions macro-economic level. Rooted in institutional economics, the approach provides some focus from these three points of view. The first one is an analysis of the agreement design, on which the land backing actions stand, between stakeholders with various goals and legitimacy. It is based on the framework of the Economics of conventions. The second one focuses on the effect of land backing actions on farmers' access to land use. An analysis grid of the different land-use access costs is developed, using in particular the transaction costs concept. The third focus is a consideration of institutional changes induced by land backing actions, via a historical analysis of the use-ownership relation as an institutional formula. This thesis maintains that negotiations between stakeholders who are involved in land backing actions hardly ever broach the subject of farmland preservation facing urbanization, aside from the question of its use. The projected farming model often founds the initiative, notably for the relationship between agriculture and environment. Nevertheless farmland backing induces a new land use access mode for farmers, which is more difficult to organize, but also much less uncertain. At the same time, the private property right is back in the use-ownership relation resulting therefrom. The property right was however relatively subservient to the private right to use, for the public interest that it represents since the mid-20th century. By not much specifying the outlines of general interest, public action let its determination at the discretion of the local private dynamics, with a risk of inducing territorial inequalities.

Dado o uso crescente de tecnologias não autorizadas e não suportadas pelo departamento de TI nas organizações, chamadas de Shadow IT, o papel da TI e a forma tradicional de gerenciar tecnologia estão mudando dentro das organizações. Shadow IT refere-se ao uso de tecnologias utilizadas pelos funcionários sem a autorização ou o suporte formal da TI para realizar as tarefas de trabalho. Motivada por este contexto, esta pesquisa tem como objetivo verificar os fatores antecedentes ao comportamento de uso da Shadow IT e a relação deste comportamento com o desempenho individual dos usuários de TI. Para alcançar tal objetivo, foi realizada uma pesquisa survey com 286 usuários de TI da área administrativa. Estes usuários são funcionários de três diferentes empresas: um órgão público, uma empresa de educação profissional e uma cooperativa de crédito, as quais compõe a amostra. Esta pesquisa obteve como resultados que os fatores Experiência do Usuário, Utilidade Percebida e Influência Social têm relação positiva significante com o uso da Shadow IT, bem como o uso da Shadow IT tem relação positiva significante com o desempenho individual do usuário de TI. Este trabalho traz implicações teóricas e práticas. Para a teoria, esta pesquisa ampliou o conhecimento sobre o uso da Shadow IT a nível individual. Ademais, um instrumento para medir o comportamento de uso da Shadow IT foi desenvolvido, o qual pode ser aplicado nas organizações para conhecer o comportamento do usuário de TI com relação ao uso destas tecnologias. A partir do conhecimento dos antecedentes do comportamento de uso da Shadow IT e qual é a sua relação com o desempenho individual do usuário de TI, os gestores podem elaborar políticas de gestão que reduzam os riscos associados a esse fenômeno, bem como potencializar os seus benefícios. / Given the increasing use of unauthorized technologies by employees in organizations, called Shadow IT, the traditional way to manage technology is changing. Shadow IT is the use of an unauthorized technology by employees, changing, thus, the role of IT is changing within organizations. Motivated by this context, this research aims to verify the antecedents factors behind Shadow IT usage behavior and the relationship of this behavior with the individual performance of IT users. To reach this goal, we performed a survey research with 286 IT users of from the administrative area. These users are employees of three different companies: a public agency, a professional education company and a financial cooperative. As results, we found that User Experience, Perceived Usefulness and Social Influence has positive relationship with Shadow IT usage, as well as the use of Shadow IT has a positive relationship with the individual performance of the IT user. This research has theoretical and practical implications. To the academia, this research has extended knowledge about Shadow IT usage at individual level. Furthermore, we also has developed an instrument to measure the Shadow IT usage behavior, which can be applied to the IT users of companies in order to know their Shadow IT usage behavior. To know the antecedents of Shadow IT usage and what is its relationship with individual performance of IT user is also important to companies. Managers must know what drives users to use Shadow IT, as well as what is the outcome of this use in terms of individual performance in order to develop policies and strategies that reduce the risks associated with this phenomenon and maximize its benefits.

Um dos motivos para o crescente desenvolvimento da área de mineração de dados encontra-se no aumento da quantidade de documentos gerados e armazenados em formato digital, estruturados ou não. A Web contribui sobremaneira para este contexto e, de forma coerente com esta situação, observa-se o surgimento de técnicas específicas para utilização nesta área, como a mineração de estrutura, de conteúdo e de uso. Pode-se afirmar que esta crescente oferta de informação na Web cria o problema da sobrecarga cognitiva. A Hipermídia Adaptativa permite minorar este problema, com a adaptação de hiperdocumentos e hipermídia aos seus usuários segundo suas necessidades, preferências e objetivos. De forma resumida, esta adaptação é realizada relacionando-se informações sobre o domínio da aplicação com informações sobre o perfil de usuários. Um dos tópicos importantes de pesquisa em sistemas de Hipermídia Adaptativa encontra-se na geração e manutenção do perfil dos usuários. Dentre as abordagens conhecidas, existe um contínuo de opções, variando desde cadastros de informações preenchidos manualmente, entrevistas, até a aquisição automática de informações com acompanhamento do uso da Web. Outro ponto fundamental de pesquisa nesta área está ligado à construção das aplicações, sendo que recursos da Web Semântica, como ontologias de domínio ou anotações semânticas de conteúdo podem ser observados no desenvolvimento de sistemas de Hipermídia Adaptativa. Os principais motivos para tal podem ser associados com a inerente flexibilidade, capacidade de compartilhamento e possibilidades de extensão destes recursos. Este trabalho descreve uma arquitetura para a aquisição automática de perfis de classes de usuários, a partir da mineração do uso da Web e da aplicação de ontologias de domínio. O objetivo principal é a integração de informações semânticas, obtidas em uma ontologia de domínio descrevendo o site Web em questão, com as informações de acompanhamento do uso obtidas pela manipulação dos dados de sessões de usuários. Desta forma é possível identificar mais precisamente os interesses e necessidades de um usuário típico. Integra o trabalho a implementação de aplicação de Hipermídia Adaptativa a partir de conceitos de modelagem semântica de aplicações, com a utilização de recursos de serviços Web, para validação experimental da proposta. / One of the reasons for the increasing development observed in Data Mining area is the raising in the quantity of documents generated and stored in digital format, structured or not. The Web plays central role in this context and some specific techniques can be observed, as structure, content and usage mining. This increasing information offer in the Web brings the cognitive overload problem. The Adaptive Hypermedia permits a reduction of this problem, when the contents of selected documents are presented in accordance with the user needs, preferences and objectives. Briefly put, this adaptation is carried out on the basis of relationship between information concerning the application domain and information concerning the user profile. One of the important points in Adaptive Hypermedia systems research is to be found in the generation and maintenance of the user profiles. Some approaches seek to create the user profile from data obtained from registration, others incorporate the results of interviews, and some have the objective of automatic acquisition of information by following the usage. Another fundamental research point is related with the applications construction, where can be observed the use of Web semantic resources, such as semantic annotation and domain ontologies. This work describes the architecture for automatic user profile acquisition, using domain ontologies and Web usage mining. The main objective is the integration of usage data, obtained from user sessions, with semantic description, obtained from a domain ontology. This way it is possible to identify more precisely the interests and needs of a typical user. The implementation of an Adaptive Hypermedia application based on the concepts of semantic application modeling and the use of Web services resources that were integrated into the proposal permitted greater flexibility and experimentation possibilities.

Le silicium est le second élément le plus abondant de la croûte terrestre et un nutriment clefs des écosystèmes aquatiques. Il existe de fortes interactions entre Si, le cycle du carbone et les processus biogéochimiques. Cette étude porte sur la variabilité de Si (amorphe-ASi, lithogène-LSi et dissous-DSi) et les isotopes de Si le long du continuum continent-océan. Nous avons étudié la variabilité saisonnière et spatiale de ASi, LSi, DSi et des isotopes dans ~20 estuaires indiens. Nous avons catégorisé les estuaires selon une analyse statistique (PCA et regroupement). Le prélèvement par les diatomées semble être le principal processus contrôlant ASi en saison sèche, surtout au Sud. L’altération et l’érosion contrôlent LSi dans les autres estuaires. En saison humide, l’impact des diatomées n’est pas observé à cause d’une trop forte charge sédimentaire et tous les estuaires sont dominés par les apports lithogéniques. Les compositions isotopiques de Si peuvent tracer les sources de Si et les interactions biogéochimiques. Les résultats isotopiques montrent une différence saisonnière claire avec un impact fort de l’altération aux deux saisons. Les bassins versants du sud-ouest sont très différents des autres bassins du fait de leur topographie et climat. L’impact de l’agriculture et de la couverture forestière est aussi clairement présent dans tous les bassins tandis que la composition isotopique de Si des eaux souterraines résulte d’une combinaison de production et dissolution de minéraux. Ainsi, cette étude montre le rôle prépondérant de l’altération et du type d’argiles formées sur les isotopes de Si, indépendamment des saisons, plutôt que des processus biologiques ou de mélange tels que rapportés précédemment. / Silicon is the second most abundant element in Earth’s crust and one of the key nutrient in aquatic ecosystems. There are strong interactions of Si with carbon cycle and biogeochemical processes. The present thesis focused on variability of silicon (amorphous-ASi, lithogenic-LSi and dissolved-DSi) and Si isotopes along the land to ocean continuum. We investigated the seasonal and spatial variability of ASi, LSi & DSi and Si isotopes in ~20 Indian estuaries. We categorize the estuaries using statistical analysis (PCA and cluster analysis). Diatom uptake seems to be the main process controlling ASi during dry period, especially in the South. Weathering and erosion control the variability of LSi in the remaining estuaries. Similarly lithogenic supply controls Si during wet period in all estuaries and no impact of diatoms was seen because of high suspended load. Si isotopic compositions trace the Si sources and biogeochemical pathways. The isotopic results exhibit clear seasonal difference with high impact of type of weathering during both seasons. They show that southwest watersheds are very special in terms of weathering regime compared to the other watersheds because of topography and climate. The impact of agriculture and forest cover on Si cycle is also clearly evidenced in all the basins during wet period. We show that groundwater Si isotopic variability results from a combination of dissolution and production of minerals. Overall, this study shows the preponderant influence of weathering and type of secondary clays on Si isotopes irrespective to the seasons, rather than the biological uptake or mixing as reported elsewhere