919 resultados para Radio classes
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This research studies the argumentative process developed by the Basis Educational Movement (MEB), using as corpus the booklet Viver é lutar , and other lesson plans of the Educational Rural Radio from Natal. It has as objectives reveal the argumentative strategies in the discursive production of MEB, exploring the meaning effects suggested by its production conditions, and the ideological positions defended, in addition to this, verify how the booklet and the radio classes dialogued in the argumentation of their theses. So, the study is guided by the Discourse Analysis presuppositions, by the Argumentation Theory, by the conceptions of Popular Education, as well as the conception language dialogical language conception, recurring to Bakhtin (1995). The research adopts the documental characteristic of qualitative nature with an interpretative basis. The analysis of the data permitted us to confirm that the pedagogical didactic material discourse of MEB was produced in a social-historical-ideological context in what the education was seen as a social liberation instrument, being able to transform the Brazilian people and the Brazilian unequal structure. The results reveal that the booklet and the classes assume a position remarkably in favor of the popular classes, structured by the argumentative techniques that intended to convince, and to persuade the auditorium. Thus, the argument was based initially on the convincing of youths and of adults for, afterwards, to construct a persuasion to the learners, in terms of referring to act on the reality to transform it, according to their desires of social justice
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A radioactive Western-blotting technique was developed by which the reactivity of Immunoglobulins (Igs) from different classes to both membrane radiolabelled and internal parasite antigens is simultaneously identified. The method includes radioiodination of parasites, polypeptide fractionation by SDS-PAGE, Western-blot transfer and autoradiography of the immunoblots developed with anti-Igs conjugates labelled with enzymes. The analysis is then performed by the comparison of common bands on the autoradiograms and the respective substrate stained nitrocellulose blots. This technique was used to analyse T. cruzi trypomastigote surface labelled antigens reactive to IgM, IgA and IgG specific antibodies. A different pattern of reactivity with acute Chagas' disease patients sera was thus obtained.
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Ce mémoire de maîtrise porte sur la contribution que pourrait apporter l’Enseignement à distance par radio (EADR) dans la réduction du taux d’échec aux examens du baccalauréat 1ère partie en Haïti. De manière spécifique, nous souhaitions élaborer un programme d’ « Enseignement à distance par radio » (EADR) afin d’aider l’ensemble des candidats bacheliers des classes de Rhéto à préparer les examens du bac 1ère partie. En Haïti, l’Enseignement à distance (EAD) est pratiquement absent. De nombreux pays ayant eu des situations similaires à Haïti ont mis en place des programmes de « Formations ouvertes et à distance » (FOAD) en complémentarité avec le mode d’enseignement classique ou en mode présentiel. La complexité de la situation exige d’envisager diverses pistes pour sortir le système éducatif haïtien de cette léthargie. Si l’on ne peut considérer l’EAD comme l’unique perspective, il est par contre pertinent et souhaitable de l’envisager comme une alternative non négligeable (Lubérisse, 2003). En nous appuyant sur les principales conditions d’efficacité des FOAD définies par Karsenti (2003), les principes théoriques de type R & D (Van der Maren, 2003?), le cadre théorique de la méthodologie de l’évaluation des besoins de Chagnon et Paquette (Institut universitaire des Centres Jeunesses de Montréal, 2005) et de Roegiers, Wouters & Gerard (1992), nous avons élaboré les grandes lignes générales de ce programme d’EADR et les avons soumises à douze (12) acteurs clés du système éducatif haïtien (4 élèves, 3 parents, 2 enseignants et 3 spécialistes de la radio ou de l’EADR). Cette ébauche de programme comportait principalement les objectifs du programme d’EADR, la méthode pédagogique, le contenu et les conditions de mise en œuvre. Des données recueillies par le biais d’entrevues individuelles il ressort que l’implantation d’un programme d’EADR peut être bénéfique au système éducatif haïtien, particulièrement sur les résultats d’examens officiels du baccalauréat 1ère partie. Les douze participants à notre recherche, croient que l’objectif poursuivi par le programme d’EADR est tout à fait réalisable et important pour le public cible. Tout en notant l’aspect positif du programme d’EADR proposé, les participants réclament certaines modifications quant à la méthode pédagogique, au contenu et aux conditions de mise en œuvre. Ainsi, les recommandations faites par les douze acteurs clés du système éducatif, jointes à notre recension nous ont permis d’élaborer un nouveau programme d’EADR revu et corrigé qui pourra servir de base à une évaluation plus large.
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Future wireless communications systems are expected to be extremely dynamic, smart and capable to interact with the surrounding radio environment. To implement such advanced devices, cognitive radio (CR) is a promising paradigm, focusing on strategies for acquiring information and learning. The first task of a cognitive systems is spectrum sensing, that has been mainly studied in the context of opportunistic spectrum access, in which cognitive nodes must implement signal detection techniques to identify unused bands for transmission. In the present work, we study different spectrum sensing algorithms, focusing on their statistical description and evaluation of the detection performance. Moving from traditional sensing approaches we consider the presence of practical impairments, and analyze algorithm design. Far from the ambition of cover the broad spectrum of spectrum sensing, we aim at providing contributions to the main classes of sensing techniques. In particular, in the context of energy detection we studied the practical design of the test, considering the case in which the noise power is estimated at the receiver. This analysis allows to deepen the phenomenon of the SNR wall, providing the conditions for its existence and showing that presence of the SNR wall is determined by the accuracy of the noise power estimation process. In the context of the eigenvalue based detectors, that can be adopted by multiple sensors systems, we studied the practical situation in presence of unbalances in the noise power at the receivers. Then, we shift the focus from single band detectors to wideband sensing, proposing a new approach based on information theoretic criteria. This technique is blind and, requiring no threshold setting, can be adopted even if the statistical distribution of the observed data in not known exactly. In the last part of the thesis we analyze some simple cooperative localization techniques based on weighted centroid strategies.
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Systematic differences in the very long baseline interferometry (VLBI) radio polarization structure and average VLBI component speeds of BL Lacertae objects and quasars support the view that the observational distinction between these classes, based in large part on the strength of their optical line emission, is meaningful; in other words, this distinction reflects significant differences in the physical conditions in these sources. Possible models providing a link between the optical and VLBI properties of BL Lacertae objects and quasars are discussed. Most VLBI polarization observations to date have been global observations made at 6 cm; recent results suggest that the VLBI polarization structure of some sources may change dramatically on scales smaller than those probed by these 6-cm observations.
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Diffuse radio emission in galaxy clusters has been observed with different size and properties. Giant radio halos (RH), Mpc-size sources found in merging clusters, and mini halos (MH), 0.1-0.5 Mpc size sources located in relaxed cool-core clusters, are thought to be distinct classes of objects with different formation mechanisms. However, recent observations have revealed the unexpected presence of diffuse emission on Mpc-scales in relaxed clusters that host a central MH and show no signs of major mergers. The study of these sources is still at the beginning and it is not yet clear what could be the origin of their unusual emission. The main goal of this thesis is to test the occurrence of these peculiar sources and investigate their properties using low frequency radio observations. This thesis consists in the study of a sample of 12 cool-core galaxy clusters which present some level of dynamical disturbances on large-scale. The heterogeneity of sources in the sample allowed me to investigate under which conditions a halo-type emission is present in MH clusters; and also to study the connection between AGN bubbles and the local environment. Using high sensitivity LOFAR observations, I have detected large-scale emission in four non-merging clusters, in addition to the central MH. I have constrained for the first time the spectral properties of diffuse emission in these double radio component galaxy clusters, and I have investigated the connection between their thermal and non-thermal emission for a better comprehension of the acceleration mechanism. Furthermore, I derived upper limits to the halo power for the other clusters in the sample, which could present large-scale diffuse emission under the detection threshold. Finally, I have reconstructed the duty-cycle of one of the most powerful AGN known, located at the centre of a galaxy cluster of the sample.
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Radio galaxies (RGs) are extremely relevant in addressing important unknowns concerning the interaction among black hole accretion, radio jets, and the environment. In the classical scheme, their accretion rate and ejection of relativistic jets are directly linked: efficient accretion (HERG) is associated with powerful edge-brightened jets (FRIIs); inefficient accretion (LERG) is associated with weak edge-darkened jets (FRIs). The observation of RGs with an inefficient engine associated with edge-brightened radio emission (FRII-LERGs) broke this scheme. FRII-LERGs constitute a suitable population to explore how accretion and ejection are linked and evaluate the environment's role in shaping jets. To this aim, we performed a multiwavelength study of different RGs catalogs spanning from Jy to mJy flux densities. At first, we investigated the X-ray properties of a sample of 51 FRIIs belonging to the 3CR catalog at z<0.3. Two hypotheses were invoked to explain FRII-LERGs behavior: evolution from classical FRIIs; the role of the environment. Next, we explored the mJy sky by studying the optical-radio properties of hundreds of RGs at z<0.15 (Best & Heckman 2012 sample). FRII-LERGs appear more similar to the old FRI-LERGs than to the young FRII-HERGs. These results point towards an evolutive scenario, however, nuclear time scale changes, star population aging, and kpc-Mpc radio structure modification do not agree. The role of the Mpc environment was then investigated. The Wen et al. 2015 galaxy clusters sample, built exploiting the SDSS survey, allowed us to explore the habitat of 7219 RGs at z<0.3. Most RGs are found to live in outside clusters. For these sources, differences among RG classes are still present. Thus, the environment is not the key parameter, and the possibility of intrinsic differences was reconsidered: we speculated that different black hole properties (spin and magnetic field at its horizon) could determine the observed spread in jet luminosity.
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Universidade Estadual de Campinas . Faculdade de Educação Física
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Aims. We calculate the theoretical event rate of gamma-ray bursts (GRBs) from the collapse of massive first-generation (Population III; Pop III) stars. The Pop III GRBs could be super-energetic with the isotropic energy up to E(iso) greater than or similar to 10(55-57) erg, providing a unique probe of the high-redshift Universe. Methods. We consider both the so-called Pop III.1 stars (primordial) and Pop III.2 stars (primordial but affected by radiation from other stars). We employ a semi-analytical approach that considers inhomogeneous hydrogen reionization and chemical evolution of the intergalactic medium. Results. We show that Pop III.2 GRBs occur more than 100 times more frequently than Pop III.1 GRBs, and thus should be suitable targets for future GRB missions. Interestingly, our optimistic model predicts an event rate that is already constrained by the current radio transient searches. We expect similar to 10-10(4) radio afterglows above similar to 0.3 mJy on the sky with similar to 1 year variability and mostly without GRBs (orphans), which are detectable by ALMA, EVLA, LOFAR, and SKA, while we expect to observe maximum of N < 20 GRBs per year integrated over at z > 6 for Pop III.2 and N < 0.08 per year integrated over at z > 10 for Pop III.1 with EXIST, and N < 0.2 for Pop III.2 GRBs per year integrated over at z > 6 with Swift.
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Over the last decade, X-ray observations have revealed the existence of several classes of isolated neutron stars (INSs) which are radio-quiet or exhibit radio emission with properties much at variance with those of ordinary radio pulsars. The identification of new sources is crucial in order to understand the relations among the different classes and to compare observational constraints with theoretical expectations. A recent analysis of the 2XMMp catalogue provided fewer than 30 new thermally emitting INS candidates. Among these, the source 2XMM J104608.7-594306 appears particularly interesting because of the softness of its X-ray spectrum, kT = 117 +/- 14 eV and N(H) = (3.5 +/- 1.1) x 10(21) cm(-2) (3 sigma), and of the present upper limits in the optical, m(B) greater than or similar to 26, m(V) greater than or similar to 25.5 and m(R) greater than or similar to 25 (98.76% confidence level), which imply a logarithmic X-ray-to-optical flux ratio log(F(X)/F(V)) greater than or similar to 3.1, corrected for absorption. We present the X-ray and optical properties of 2XMM J104608.7-594306 and discuss its nature in the light of two possible scenarios invoked to explain the X-ray thermal emission from INSs: the release of residual heat in a cooling neutron star, as in the seven radio-quiet ROSAT-discovered INSs, and accretion from the interstellar medium. We find that the present observational picture of 2XMM J104608.7-594306 is consistent with a distant cooling INS with properties in agreement with the most up-to-date expectations of population synthesis models: it is fainter, hotter and more absorbed than the seven ROSAT sources and possibly located in the Carina Nebula, a region likely to harbour unidentified cooling neutron stars. The accretion scenario, although not entirely ruled out by observations, would require a very slow (similar to 10 km s(-1)) INS accreting at the Bondi-Hoyle rate.
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Given a continuous map f : K -> M from a 2-dimensional CW complex into a closed surface, the Nielsen root number N(f) and the minimal number of roots mu(f) of f satisfy N(f) <= mu(f). But, there is a number mu(C)(f) associated to each Nielsen root class of f, and an important problem is to know when mu(f) = mu(C)(f)N(f). In addition to investigate this problem, we determine a relationship between mu(f) and mu((f) over tilde), when (f) over tilde f is a lifting of f through a covering space, and we find a connection between this problems, with which we answer several questions related to them when the range of the maps is the projective plane.
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We study rf spectroscopy of a lithium gas with the goal to explore the possibilities for photoemission spectroscopy of a strongly interacting p-wave Fermi gas. Radio-frequency spectra of quasibound p-wave molecules and of free atoms in the vicinity of the p-wave Feshbach resonance located at 159.15G are presented. The spectra are free of detrimental final-state effects. The observed relative magnetic-field shifts of the molecular and atomic resonances confirm earlier measurements realized with direct rf association. Furthermore, evidence of molecule production by adiabatically ramping the magnetic field is observed. Finally, we propose the use of a one-dimensional optical lattice to study anisotropic superfluid gaps as most direct proof of p-wave superfluidity.
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Since the beginning of Physical Education entrance in the brazilin public schools, the game has been frequently used as content, and in the course of time that practice seems to be intensified. In spite of many approaches of different purposes to justify its pedagogic usefulness, the game has been used as an indiscriminate way due to the fascination that it provides to the students. The present study searches for a description and analysis of children`s (10-12 years old) attitudes behaviors in games, on Physical Education classes, inside a public school. The study was accomplished with the researcher also attending as a teacher (action research). For the accomplishment of the study 55 children were filmed in four different games, of different kinds (exposed, transformed, and spontaneous). The classes` description and analysis were focused in the attitude axis and it was defined four topics for the discussion: Conflicts, Respect of rules, Expressiveness, and Competitiveness. The relationship between the individual with the game and its culture were pointed as the main characteristics in the configuration of the ludicrous activity atmosphere. It was also possible to observe specific situations of this relationship, once the games were limited to the social games (Piaget category), in a school atmosphere where children have students roles. Due to the obtained results, the study proposes a reflexive practice in which the students notice their own attitudes and try to adapt the game to their needs and not he other way around. In this perspective, the teacher has an important mediator roll, once he will be responsible to point out the students` difficulties and promote discussions in favor to provide teamwork.
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Nine classes of integrable boundary conditions for the eight-state supersymmetric model of strongly correlated fermions are presented. The boundary systems are solved by using the coordinate Bethe ansatz method and the Bethe ansatz equations for all nine cases are given.
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A method for the accurate computation of the current densities produced in a wide-runged bi-planar radio-frequency coil is presented. The device has applications in magnetic resonance imaging. There is a set of opposing primary rungs, symmetrically placed on parallel planes and a similar arrangement of rungs on two parallel planes surrounding the primary serves as a shield. Current densities induced in these primary and shielding rungs are calculated to a high degree of accuracy using an integral-equation approach, combined with the inverse finite Hilbert transform. Once these densities are known, accurate electrical and magnetic fields are then computed without difficulty. Some test results are shown. The method is so rapid that it can be incorporated into optimization software. Some preliminary fields produced from optimized coils are presented.