Cette thèse a pour objet l’étude des effets de cohérence de la propagation d’ondes en milieu désordonné, à l’aide d’atomes ultrafroids. Ces systèmes permettent un contrôle précis de paramètres clés, tels que la dimensionnalité, les interactions, la vitesse initiale des atomes et le potentiel externe. Utilisant cette flexibilité, il a été possible de réaliser des expériences en régime fortement et faiblement localisé. La première expérience traite de l’expansion d’un condensat, dont une fraction maximale de 20% est localisée, permettant ainsi l’observation de la localisation d’Anderson en 3D. Lors de la seconde expérience, les atomes ont été envoyés dans un désordre quasi 2D avec une vitesse initiale bien définie. Il a été possible d’observer la distribution en impulsions des atomes, et ainsi de mesurer le temps de libre parcours moyen et le temps de transport. La rétrodiffusion cohérente s’est clairement manifestée sous la forme d’un pic dans la direction opposée à la direction initiale. L’amplitude et la largeur de ce pic ont été étudiées, et les résultats sont en accord avec la théorie. Microscopiquement, la rétrodiffusion cohérente a pour origine l’interférence constructive entre chemins à diffusions multiples symétriques par renversement du temps (symétrie T). Cette symétrie de la propagation d’ondes a été ensuite manipulée. Un déphasage précis a été introduit grace à un pulse de gradient de champ magnétique, qui détruit la symétrie T ainsi que la rétrodiffusion cohérente, sauf pour un bref instant : une résurgence du pic est alors observée. Ce nouvel effet démontre explicitement le rôle de la cohérence et de la symétrie T dans la localisation faible. / In this manuscript the coherence effects of wave propagation in disordered potentials is studied. Our experiment uses ultracold atoms as a probe, a system allowing for a very good control over parameters such as the dimensionality, interactions, initial velocity of the atoms, and the potential landscape. Exploiting this flexibility we were able to perform experiments in the strongly and the weakly localized regime. In the former the 3D expansion of a BEC was monitored in real space, resulting in the observation of 3D Anderson localization with a maximum localized fraction of about 20%. In the latter the atoms were launched into a quasi-2D disorder with a well defined initial velocity. Monitoring the momentum space distribution the mean scattering time and the transport time can be directly measured, and coherent backscattering (CBS) is clearly visible as a peak in the backwards direction. In a first set of experiments the evolution of the CBS amplitude and width were recorded and found to be in good agreement with theory. Microscopically, CBS stems from the constructive interference of time-reversed multiply scattered paths. In a second set of CBS experiments we manipulated the time-reversal symmetry (TRS) of the wave propagation. A surgical dephasing was introduced via a shortly pulsed gradient field, which brakes TRS and suppresses CBS except for a brief moment, when a revival of CBS is observed. This novel effect showcases explicitly the role of coherence and TRS in Coherent Backscattering and weak localization.

High-level language virtual machines (HLL VMs) have been playing a key role as a mechanism for implementing programming languages. Languages that run on these execution environments have many advantages over languages that are compiled to native code. These advantages have led HLL VMs to gain broad acceptance in both academy and industry. However, much of the research in this area has been devoted to boosting the performance of these execution environments. Few eorts have attempted to introduce features that automate or facilitate some software engineering activities, including software testing. This research argues that HLL VMs provide a reasonable basis for building an integrated software testing environment. To this end, two software testing features that build on the characteristics of a Java virtual machine (JVM) were devised. The purpose of the rst feature is to automate weak mutation. Augmented with mutation support, the chosen JVM achieved speedups of as much as 95% in comparison to a strong mutation tool. To support the testing of concurrent programs, the second feature is concerned with enabling the deterministic re-execution of Java programs and exploration of new scheduling sequences / Máquinas virtuais de linguagens de programação têm desempenhado um papel importante como mecanismo para a implementação de linguagens de programação. Linguagens voltadas para esses ambientes de execução possuem várias vantagens em relação às linguagens compiladas. Essas vantagens fizeram com que tais ambientes de execução se tornassem amplamente utilizados pela indústria e academia. Entretanto, a maioria dos estudos nessa area têm se dedicado a aprimorar o desempenho desses ambientes de execução e poucos têm enfocado o desenvolvimento de funcionalidades que automatizem ou facilitem a condução de atividades de engenharia de software, incluindo atividades de teste de software. Este trabalho apresenta indícios de que máquinas virtuais de linguagens de programação podem apoiar a criação de ambientes de teste de software integrado. Para tal, duas funcionalidades que tiram proveito das características de uma máquina virtual Java foram desenvolvidas. O propósito da primeira funcionalidade e automatizar a condução de atividades de mutação fraca. Após a implementação de tal funcionalidade na máquina virtual Java selecionada, observou-se um desempenho até 95% melhor em relação a uma ferramenta de mutação forte. Afim de apoiar o teste de programas concorrentes, a segunda funcionalidade permite reexecutá-los de forma determinística além de automatizar a exploração de que novas sequências de escalonamento

High precision measurements of a weak interaction decay were conducted to search for possible variation of the decay rate parameter caused by an antineutrino flux. The experiment searched for variation of the ⁵⁴Mn electron capture decay rate parameter to a level of precision of 1 part in ∼10⁵ by comparing the difference between the decay rate in the presence of an antineutrino flux ∼3×10¹² cm^-2sec^-1 and no flux measurements. The experiment is located 6.5 meters from the reactor core of the High Flux Isotope Reactor (HFIR) in Oak Ridge National Laboratory. A measurement to this level of precision requires a detailed understanding of both systematic and statistical errors. Otherwise, systematic errors in the measurement may mimic fundamental interactions. <div><br></div><div>The gamma spectrum has been collected from the electron capture decay of ⁵⁴Mn. What differs in this experiment compared to previous experiments are, (1) a strong, uniform, highly controlled, and repeatable source of antineutrino flux, using a reactor, nearly 50 times higher than the solar neutrino flux on the Earth, (2) the variation of the antineutrino flux from HFIR is 600 times higher than the variation in the solar neutrino flux on the Earth, (3) the extensive use of neutron and gamma-ray shielding around the detectors, (4) a controlled environment for the detector including a fixed temperature, a nitrogen atmosphere, and stable power supplies, (5) the use of precision High Purity Germanium (HPGe) detectors and finally, (6) accurate time stamping of all experimental runs. By using accurate detector energy calibrations, electronic dead time corrections, background corrections, and pile-up corrections, the measured variation in the ⁵⁴Mn decay rate parameter is found to be δλ/λ=(0.034±1.38)×10^-5. This measurement in the presence of the HFIR flux is equivalent to a cross-section of σ=(0.097±1.24)×10^-25cm². These results are consistent with no measurable decay rate parameter variation due to an antineutrino flux, yielding a 68% confidence level upper limit sensitivity in δλ/λ <= 1.43×10^-5 or σ<=1.34×10^-25cm² in cross-section. The cross-section upper limit obtained in this null or no observable effect experiment is ∼10⁴ times more sensitive than past experiments reporting positive results in ⁵⁴Mn.</div>

First, we provide new classes of initial data, that grant short time uniqueness of the associated weak Leray-Hopf solutions of the three dimensional Navier-Stokes equations. The main novelty here is the establishment of certain continuity properties near the initial time, for weak Leray-Hopf solutions with initial data in supercritical Besov spaces. The techniques used here build upon related ideas of Calder&oacute;n. Secondly, we prove local regularity up to the at part of the boundary, for certain classes of solutions to the Navier-Stokes equations, provided that the velocity field belongs to L_&infin;(-1; 0; L^{3, &beta;}(B(1) &xcap; &Ropf;³ ₊)) with 3 &le; &beta; &lt; &infin;. What enables us to build upon the work of Escauriaza, Seregin and &Scaron;ver&aacute;k [27] and Seregin [100] is the establishment of new scale-invariant estimates, new estimates for the pressure near the boundary and a convenient new &epsiv;-regularity criterion. Third, we show that if a weak Leray-Hopf solution in &Ropf;³ ₊&times;]0,&infin;[ has a finite blow-up time T, then necessarily lim_t&uarr;T&verbar;&verbar;v(&middot;, t)&verbar;&verbar;_{L^3,&beta;(&Ropf;³ ₊)} = &infin; with 3 &lt; &beta; &lt; &infin;. The proof hinges on a rescaling procedure from Seregin's work [106], a new stability result for singular points on the boundary, suitable a priori estimates and a Liouville type theorem for parabolic operators developed by Escauriaza, Seregin and &Scaron;ver&aacute;k [27]. Finally, we investigate a notion of global-in-time solutions to the Navier- Stokes equations in &Ropf;³, with solenoidal initial data in the critical Besov space ?^-1/4_4,&infin;(&Ropf;³), which has certain continuity properties with respect to weak&ast; convergence of the initial data. Such properties are motivated by the strategy used by Seregin [106] to show that if a weak Leray-Hopf solution in &Ropf;³&times;]0,&infin;[ has a finite blow-up time T, then necessarily lim_t&uarr;T &verbar;&verbar;v(&middot;, t)&verbar;&verbar;_{L₃(&Ropf;³)} = &infin;. We prove new decomposition results for Besov spaces, which are key in the conception and existence theory of such solutions.

This thesis is an inquiry into the challenges to the role of civic organisations in political reform during and after political transitions. The major question this research addresses is: How do institutions and institutional dynamics constrain political reform during a transition? The thesis examines how demands for reform by non-governmental organisations in Lebanon and Libya were not translated into concrete political decisions taken by regimes during a transition period. The thesis suggests that the combination of weak states and power-sharing agreements marginalizes civic organisations, and poses institutional constraints on the likelihood of reform. The thesis is based on contemporary research on events and reform trajectories in Lebanon and Libya, with a focus on the demands and strategies employed by activists during periods of transition. Lebanon between 2005 and 2010 and Libya between 2011 and 2013 underwent critical political events but subsequently did not adopt political reforms despite demands by civic organisations in two main areas: the electoral system in Lebanon and the constitutional process in Libya. A study of these two reform campaigns reveals deeply entrenched historical patterns and elements of continuity that led to path dependent outcomes during transition. By utilising theory and concepts from the perspective of historical institutionalism, the thesis identifies the factors behind path dependent outcomes in Lebanon and Libya. I argue that the transitions in Lebanon and Libya were a result of only ‘partially' critical junctures. The thesis builds on the approach of path dependence by offering insights as to how historically inherited institutional dynamics from the previous regime can cause junctures to be only ‘partially' critical for the broader political order. The main source of data comes from participant observations, interviews and focus groups with two organisations that tried to advance electoral reform and constitutional development.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O trabalho busca analisar os problemas envolvendo a efetivação do direito à saúde no Brasil, os conflitos alocativos subjacentes à temática e o papel das instituições representativas, do Judiciário e da sociedade civil neste processo. Pretende-se reafirmar a importância da proteção do direito à saúde e, ao mesmo tempo, criticar uma certa euforia doutrinária e jurisprudencial que se instalou nos últimos anos e passou a compreender o Judiciário como o último guardião das promessas constitucionais não cumpridas pelos ramos representativos. O trabalho analisa as experiências constitucionais de países que não apostam no dogma da supremacia judicial e tentam conciliar a revisão judicial com mecanismos mais democráticos. A partir daí propõe o marco teórico das teorias do diálogo institucional como uma alternativa menos unilateral para enfrentar os desafios desencadeados no campo sanitário. No trabalho enfatiza-se a importância pelas preocupações com a efetividade da constituição, mas propõe-se uma reflexão sobre qual seria a melhor alternativa para tanto, chegando-se à conclusão contra-intuitiva de que talvez o caminho mais eficaz passe por um controle judicial fraco, que não despreze as potencialidades do Direito, mas que aposte mais na democracia e na interação sinérgica entre os ramos representativos e a sociedade civil. / The work seeks to analyze problems involving the implementation of the right to health in Brazil, the distributive conflict underlying the theme and the role of representative institutions, the judiciary and civil society in this process. It is intended to reaffirm the importance of protecting the right to health and, at the same time, to criticize a certain euphoria that took place in recent years and came to understand the judiciary as the ultimate guardian of constitutional promises not kept by the representative branches. This article examines the constitutional experiences of countries that do not embrace the doctrine of judicial supremacy and struggle themselves to balance judicial review with more democratic mechanisms. Thereafter it is offered the theoretical framework of theories of institutional dialogue as a less one-sided alternative to meet the challenges triggered in the field of health care. The work emphasizes the importance by concerns about the effectiveness of the constitution, but it proposes a reflection on what would be the best alternative for it, coming to the counterintuitive conclusion that perhaps the most effective way is a weak from of judicial review, which do not disregard the potential of the Law, but that values more democracy and synergistic interaction between the branches and representative civil society.

Made available in DSpace on 2014-12-17T15:42:14Z (GMT). No. of bitstreams: 1 AndreiaCL_TESE.pdf: 5308625 bytes, checksum: 13df680734f410713c3992d8e7be1c8f (MD5) Previous issue date: 2010-12-27 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Orthoferrites AFeO3 (A = rare earth) are an important class of perovskite oxides that exhibit weak ferromagnetism. These materials find numerous applications as chemical sensors, cathodes for fuel cells and catalysis, which make them interesting from the standpoint of science and technology. Their structural, electrical and magnetic properties are dependent on many factors such as the preparation method, heat treatment conditions, chemical composition and replacement of cations in sites A and/or B. In this paper, LaFe1-xMnxO3 (0 &#8804; x &#8804; 1) orthoferrites-type was prepared by Pechini method and Microwave-assisted combustion reaction in order to evaluate the influence of synthesis route on the formation of oxide, as well as the effect of parcial replacement of iron by manganese and heat treatment on the magnetic properties. The precursor powders were calcined at 700?C, 900?C, 1100?C and 1300?C for 4 hours and they were characterized by the techniques: Thermogravimetric analysis (TGA), X ray diffraction (XRD), Refinement by Rietveld method, Scanning electron microscopy (SEM), Reduction temperature programmed (RTP) and Magnetic hysteresis measurements performed at room temperature. According to the XRD patterns, the formation of perovskite phase with orthorhombic structure was observed for the systems where 0 &#8804; x &#8804; 0.5 and rhombohedral for x = 1. The results also showed a decrease of lattice parameters with the parcial replacement of iron by manganese and consequently a reduction in cell volume. The hysteresis curves exhibited weak ferromagnetism for the systems prepared by both synthesis methods. However, a dependence of magnetization as a function of dopant content was observed for samples produced by Pechini method. As for the systems prepared by combustion reaction, it was found that the secondary phases exert a strong influence on the magnetic behavior / Ortoferritas AFeO3 (A = terra rara) constituem uma importante classe de ?xidos perovskita que exibem ferromagnetismo fraco. Estes materiais encontram in?meras aplica??es como sensores qu?micos, catodos para c?lulas a combust?veis e na ?rea de cat?lise, o que os fazem interessantes do ponto de vista cient?fico e tecnol?gico. Suas propriedades estruturais, el?tricas e magn?ticas s?o dependentes de v?rios fatores tais como: o m?todo de prepara??o, condi??es do tratamento t?rmico, composi??o qu?mica e substitui??o de c?tions nos s?tios A e/ou B. Neste trabalho, ortoferritas do tipo LaFe1-xMnxO3 (0 &#8804; x &#8804; 1) foram preparadas pelo m?todo Pechini e pela rea??o de combust?o assistida por microondas com a finalidade de avaliar a influ?ncia da rota de s?ntese na forma??o do ?xido, assim como o efeito da substitui??o parcial do ferro por mangan?s e do tratamento t?rmico nas propriedades magn?ticas. Os p?s precursores foram calcinados a 700?C, 900?C, 1100?C e 1300?C por 4 horas e caracterizados atrav?s das t?cnicas: An?lise termogravim?trica (TG), Difra??o de raios X (DRX), Refinamento pelo m?todo de Rietveld, Microscopia eletr?nica de varredura (MEV), Redu??o a temperatura programada (RTP) e Medidas de histerese magn?ticas realizadas ? temperatura ambiente. De acordo com os difratogramas, a forma??o da fase perovskita com estrutura ortorr?mbica foi observada para os sistemas onde 0 &#8804; x &#8804; 0,5 e, rombo?drica para x = 1. Os resultados tamb?m mostraram uma diminui??o dos par?metros de rede com a substitui??o parcial do ferro por mangan?s e, conseq?entemente uma redu??o do volume da c?lula unit?ria. As curvas de histerese exibiram ferromagnetismo fraco para os sistemas preparados por ambos os m?todos de s?ntese. Entretanto, uma depend?ncia da magnetiza??o em fun??o do teor de dopante foi observada para as amostras produzidas pelo m?todo Pechini. J? para os sistemas preparados por rea??o de combust?o, verificou-se que as fases secund?rias exercem forte influ?ncia no comportamento magn?tico

Orientador: Adrian Oscar Dongo Montoya / Banca: Orly Zucatto Mantovani de Assis / Banca: Maria Suzana S. Menin / Resumo: Decorridos vinte anos da publicação no Brasil de Psicogênese da língua escrita, de Emília Ferreiro e dez anos da adoção da teoria construtivista pelos Parâmetros Curriculares Nacionais, temos constatado resultados que apontam para um insucesso dos alunos em relação ao ensino/aprendizagem de leitura/escrita. A teoria construtivista teria se mostrado inadequada para o enfrentamento da questão? Poderíamos apontá-la como causadora do insucesso dos alunos em relação às práticas de leitura/escrita? Deveríamos desconsiderar a revolução conceitual de Emília Ferreiro, voltar-lhe as costas e reconhecer como mais adequada a volta ao método fônico? Os professores teriam compreendido, verdadeiramente, e posto em ação, os pressupostos de Ferreiro, apoiando neles as práticas escolares de ensino/aprendizagem de leitura/escrita? Ou tê-los-iam compreendido como um novo método de ensino ou novo teste para a avaliação da maturidade dos alunos com vistas à sua classificação? Por que é que a divulgação da proposta construtivista de Ferreiro não resultou ainda em melhor desempenho dos alunos nas práticas de leitura/escrita? Esta investigação procurou compreender as prováveis razões do insucesso dos alunos em leitura/escrita e sua relação com as propostas construtivistas de Emília Ferreiro. Foram realizadas entrevistas e sessões de observação da sala de aula, com 20 professores do Ensino Fundamental I, de seis escolas municipais da cidade de Ourinhos, com melhor ou pior desempenho na Prova Brasil 2005. A partir da análise da Bibliografia e com base no questionamento de professores e na observação desses e de seus alunos durante atividades realizadas em sala de aula, pretendeuse conhecer e analisar a concepção subjacente às práticas, e as próprias práticas adotadas para o ensino/aprendizagem de leitura/escrita. Concluiu-se que os professores... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Twenty years after the "Psicogênese da língua escrita" was published, in Brazil by Emília Ferreiro, and ten years after the constructivism theory was adopted, as part of Brazil's "Parameters for National Syllabuses", the results obtained have pointed to a worse performance in teaching and learning with regards to reading and writing. Therefore, we might ask, has the constructivism theory proved itself inadequate for the job? Could we point it out as being a cause of student's lack of success as to reading and writing? Should we put Emília Ferreiro's "conceptual revolution" to one side, turn our backs on it, and admit that it would be better to go back to the previously used phonic method. Had the teachers understood correctly and applied all that had been proposed by Ferreiro? Were they using these tools correctly to support their school activities, of teaching and learning of reading and writing? Or did they understand it to be a kind of new method of teaching or a sort of evaluation test that tested the students' maturity, with a view to their classification? Why after the publishing of Ferreiro's constructivism proposal haven't the student's performances improved, with regards to reading and writing? This study attempts to highlight the probable reasons for the student's lack of success in reading and writing, and its relation to Emília Ferreiro's constructivism proposals. Interviews were made as well as sit in class observation were done, with twenty teachers at six Fundamental Level 1 schools in the town of Ourinhos, SP State . The schools chosen were those that had been awarded the best and the worst performance rating in the Brazilian Governments year 2005 test (Prova Brasil). Based on the analysis of literature and the replies given, as well as by watching the way teachers performed in class, it was intended to get to understand and analyse... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2016-04-26T14:55:21Z (GMT). No. of bitstreams: 1 Amaury de Souza Amaral.pdf: 6080140 bytes, checksum: 0cb16a7bf0b53c8f66a4c49527ebc928 (MD5) Previous issue date: 2015-05-08 / The effects of globalization are felt in all countries. Many have socioeconomic scenarios marked by inequality and by indebtedness. In order to liquidate its debts, they capture resources abroad with the issue of the so-called sovereign bonds. The rating agencies are companies that assess risks before the eventual entitling of these titles and issue opinions. Even that they disclose their methodology of evaluation, in fact there is a huge subjective field, which ultimately influence and, often, increasing the domestic interest rate. Although not everyone realizes the size of the social impact of this component, they effectively change the daily reality experienced by citizens. Because of it, we became interested in studying the effects of the impacts caused by risk factors that enter in the economy. For this reason, it was used as a basis a simplified model that simulates an artificial economy, designed to study a network of credit and the effects of fluctuations in interest rates. This model was chosen also for allowing us to capture amplitudes of economic fluctuations in responses to shocks promoted by the insertion of the interest in an evolutionary process. But it was necessary to go beyond. In this study, we propose an extended version of the simplified economic model by inserting a network of consumers with all its amplitude; this is because the previous model was based on the Say law, that starts from the assumptions that all offer generates its own demand. Thus, it does not permit us to investigate the impacts of the interest on the choices made by consumers in their buying process. The Complex System Theory, and all the development that is currently available for computing, among them the modern algorithms with their accuracy and speed, were fundamental to the achievement of the work. We have, also, progressed in the rupture of the traditional economic analyzes characterized by a top-down approach and, through agents models based, we could adopt a bottom-up approach. This was possible with the integration of macro-parameters associated with a micro level of processing. The main conclusion of this work is that the formation of agglomerates (clusters) between businesses, banks and families encourage economic agents. The agents connected by strong ties are benefited to the extent that the asymmetry in the distribution of wealth between firms and households is reduced. On the other hand, the increase in the interest rate leads to a fall in the connections between the agents, causing a dilution of the network and an increase in the asymmetry of the sharing of wealth / cenários socioeconômicos marcados pela desigualdade e pelo endividamento. Para saldarem suas dívidas captam recursos no exterior com a emissão dos chamados títulos soberanos. As agências de rating são empresas que avaliam riscos diante do eventual inadimplemento destes títulos e emitem opiniões. Ainda que divulguem sua metodologia de avaliação, a bem da verdade, existe nela um enorme campo subjetivo, que acaba por influenciar e, não raras vezes, majorar as taxas de juros domésticos. Muito embora nem todos percebam o tamanho do impacto social deste componente, eles efetivamente alteram a realidade vivenciada pelo cidadão em seu dia-a-dia. Assim, interessou-nos estudar os efeitos dos impactos causados pelos fatores de risco que adentram à economia. Para isso, foi utilizado como base um modelo simplificado que simula uma economia artificial, concebido para se estudar uma rede de crédito e os efeitos das flutuações dos juros. Esse modelo foi o escolhido também por permitir capturar as amplitudes das flutuações econômicas em respostas a choques promovidos através da inserção dos juros em um processo evolutivo. Mas foi necessário ir além. Neste trabalho propomos uma versão estendida do modelo econômico simplificado por meio da inserção de uma rede de consumidores com toda a sua amplitude; isto porque o modelo anterior estava baseado na lei de Say, que parte da premissa que toda oferta gera sua demanda. Assim, ele não permite investigar os impactos dos juros sobre as escolhas dos consumidores em seu processo de compra. A teoria dos sistemas complexos e todo o ferramental que atualmente é disponível pela computação, dentre eles os modernos algoritmos com sua precisão e rapidez, foram fundamentais para a consecução do trabalho. Conseguimos, igualmente, avançar na ruptura das análises econômicas tradicionais caracterizadas pela abordagem top down e, por meio de modelos baseados em agentes, pode-se adotar uma abordagem bottom-up. Isto foi possível com as inserções dos macro-parâmetros associados ao processamento a nível micro. A conclusão principal do trabalho é que a formação de aglomerados (clusters) entre empresas, bancos e famílias favorecem os agentes econômicos. Os agentes conectados por laços fortes são beneficiados na medida em que diminui a assimetria na distribuição de riquezas entre firmas e famílias. Por outro lado, o aumento da taxa de juros leva a uma quebra nas conexões entre os agentes, causando a diluição da rede e aumento na assimetria da partilha da riqueza

Le domaine de notre recherche est la décision stratégique au sein des organisations. Plus précisément il s'agit de l'aide à la prise de décision stratégique et de la problématique de l'acquisition des informations utiles pour de telles décisions. D'un côté les ‘informations de terrain' issus des contacts entre personnes, des réunions professionnelles, etc. demeurent essentielles pour les dirigeants. D'un autre côté les journaux quotidiens nationaux et internationaux fournissent un volume considérable de données que l'on peut qualifier de données brutes (Raw data). Mais, outre ces sources classiques, le recueil des informations a évolué de façon considérable avec l'avènement des technologies de l'information et notamment de l'Internet pour ce qui concerne dans notre recherche. Nous avons choisi le domaine concernant l'acquisition des informations de terrain fournies par les journaux nationaux quotidiens : les journaux quotidiens colombiens pour ce qui concernera notre étude empirique. Pour acquérir cette information nous avons proposé sur la base d'une recherche du type « Action Design Research », de concevoir, de construire et d'expérimenter un artéfact permettant de détecter des signaux faibles potentiels issus des données extraites d'Internet et qui aideraient les dirigeants de l'entreprise à découvrir et comprendre leur environnement. L'artéfact a été conçu et construit en deux phases utilisant des concepts théoriques liés à la surcharge de données, à la veille stratégique notamment la VAS-IC® (Veille Anticipative Stratégique – Intelligence Collective) et sur les caractéristiques souhaitables des systèmes informatisés d'aide à la décision stratégique. Après sa construction, l'artéfact a été expérimenté sur un terrain permettant d'évaluer son effectivité. Cette expérimentation a permis d'améliorer nos connaissances sur la pertinence des données numériques dans le processus de la prise de la décision. Les décideurs impliqués ont également pu d'intégrer des nouvelles pratiques adaptées à leurs besoins d'information. / Our research area is around the strategic decision within organizations. More precisely, it is applicable as an aid for strategic decision-making and detecting useful information for such decisions. On the one hand, the ‘information from the field' from the contacts between individuals, business meetings, etc. is always essential for managers. On the other hand, national and international newspapers can provide a considerable volume of data that can be defined as the raw data. However, besides these classical sources, gathering information has changed dramatically with the advent of information technology and particularly internet that is related to our research. We chose the area for the acquisition of ‘information from the field' provided by the national daily newspapers: the Colombian newspaper which concerns to our empirical study. In order to detect weak signals of potential internet base issues which help managers to discover and understand their environment, we proposed a research based on “Action Design Research” type and then applied for designing, building and testing an artifact to gain the required information. The artifact has been designed and built in two phases that is included of using theoretical concepts about the data overload, environmental scanning particularly the “anticipatory and collective environmental scanning model” (VAS-IC®) and the desirable characteristics of strategic decision making support systems. After its construction, the artifact applied to real experimentation that has allowed us to evaluate its effectiveness. Afterwards, we improved our knowledge about the relevance of digital data in the decision making process. The results of all the involved decision makers have been able to integrate these new practices into their information needs.