Os media e a Europa : O sistema mediático da união, a sociedade civil e a identidade europeia

O alargamento da União Europeia de quinze a vinte e cinco Estados membros suscita numerosas interrogações sobre a coerência e a viabilidade de um tal projecto. Contudo, há quem considere que os media poderão assumir um papel importante nesta matéria, favorecendo a construção de uma sociedade civil e de uma identidade europeias vigorosas. A fragmentação da paisagem mediática europeia e a dimensão norte-americana dos media transnacionais provocam porém um certo cepticismo…

Actividade e comunicação: o sujeito perante os media

O presente artigo apresenta uma perspectiva material de compreensão da relação entre os sujeitos e os media centrada no conceito de actividade. A partir da discussão deste conceito no contexto de diferentes abordagens no campo dos estudos da comunicação, pretendemos centrarmo-nos na denominada “teoria da actividade” para introduzir uma concepção da actividade enquanto vector central da relação entre sujeito e media. Esta relação constrói-se de acordo com esta perspectiva, não como uma relação passiva baseada na exposição, mas sim como uma relação produtiva de uso dos media enquanto objectos no contexto de actividades colectivas e individuais de objectivação de uma relação produtiva de consumo suportada na mediação de artefactos.

Strategy Lab Experiences: Bathtub Dynamics

As the world changes ever faster, managers increasingly recognize the complexity and turbulence of the business systems in which they are embedded. The management problems are dynamic, while the dynamic complexity comes frequently from few variables with circle and delays interrelations that introduce nonlinearities.The present paper describes a research conducted in Portugal with two different groups - one, academic; the other, professional - where we explored the subjects’ understanding of some basic systems thinking concepts such as stock-flow relationship, feedback processes and time delays.

Assessment of a strategy for the control of respiratory diseases in children

A programme for the control of respiratory diseases in children was conceived for the State of S. Paulo, Brazil, in 1986. Its progress thereafter and the epidemiology of the diseases concerned are examined. Apart from an inquiry into the 64 existing State local health authorities, a sample of 18,255 cases of children assisted by the programme at different levels, including both in-patient and outpatient care, is analysed. Each case record included information about identification (child, doctor and health facility), reasons for calling, diagnoses made and outcome of treatment. Further data were also sought from hospitals and from State mortality records. The programme was found to be poorly implemented in the State but, where implemented, it showed itself capable of resolving problems (only 0.5% of the cases could not be handled) as also of changing ongoing trends (more than 50% reduction in hospital admission rates). Individual assessment of each item of the programme indicated its bottlenecks. Regarding the epidemiology of respiratory diseases, it is observed that the major burden to health services comes from children aged less than five, and that the most important diseases are wheezing illnesses and pneumonia. Morevoer, they were found to be significantly associated (p = 0.000) so that a child in the community presenting wheezing diseases is 5 times more likely to develop pneumonia than a child with any other respiratory diagnosis. Similarly, among the under five deaths it was found that the risk for pneumonia is 3 times greater for children who died presenting wheezing diseases than it is for children with any other sort of diagnosis. In conclusion, the programme is deemed to be efficient and effective but its efficacy is marred by administrative flaws. The successful control of respiratory problems in childhood is related to a proper appreciation of the importance of wheezing diseases.

Power converter topologies for wind energy conversion systems: Integrated modeling, control strategy and performance simulation

This paper presents new integrated model for variable-speed wind energy conversion systems, considering a more accurate dynamic of the wind turbine, rotor, generator, power converter and filter. Pulse width modulation by space vector modulation associated with sliding mode is used for controlling the power converters. Also, power factor control is introduced at the output of the power converters. Comprehensive performance simulation studies are carried out with matrix, two-level and multilevel power converter topologies in order to adequately assert the system performance. Conclusions are duly drawn.

Antropologia dos media: perspectivas e leituras

No presente artigo procurar-se-á fazer uma exposição de síntese sobre uma área emergente da Antropologia, denominada por Antropologia dos Media, estabelecendo de forma geral o seu percurso enquanto sub-disciplina académica e apresentando alguns dos trabalhos e autores que contribuíram decisivamente para o seu estabelecimento enquanto área de interesse e de produção no campo discursivo da Antropologia. Sendo esta uma área relativamente desconhecida em Portugal, pretende-se delinear um percurso de certa forma tradicional evocando os autores de maior visibilidade no contexto académico presente, percorrendo a história que estes e os seus antecessores construíram.

A televisão na era digital: qual o modelo mais adequado para o serviço público de televisão na plataforma internet?

Dissertação apresentada à Escola Superior de Comunicação Social como parte dos requisitos para obtenção de grau de mestre em Audiovisual e Multimédia.

Informação ou dramatização do risco: os media e os novos riscos

Também transversal a todos os casos analisados é o importante papel desempenhado pelos meios de comunicação social. Nas sociedades contemporâneas, os conflitos sociais apenas adquirem existência na esfera pública quando recebem cobertura mediática. No caso particular das questões de risco, tal é especialmente verdade. Os mass media, por via do chamado efeito do Agenda Setting, conferem existência a problemas que de outra forma estariam ausentes da esfera pública. Ao divulgarem um caso de risco, pressionam o poder político para tomar medidas ou justificar as opções tomadas, assim como a comunidade científica para sustentar o aconselhamento prestado.

Factores que inciden en el habito de fumar de escolares de educación basica y media del Chile

INTRODUCCIÓN: Considerando la indiscutible evidencia de los efectos adversos del tabaco, para la salud, millones de personas continúan fumando. La situación es de mayor gravedad, ya que muchos de estos fumadores y la mayoría de los nuevos fumadores, tanto en Chile, como en otros países, son adolescentes. Los objetivos de este estudio fueron determinar la prevalencia de tabaquismo en escolares chilenos y cuantificar el impacto relativo que ejercen factores socioeconómicos, socioculturales, familiares, de exposición a medios de comunicación de masas, demográficos, educacionales y psicosociales, sobre la prevalencia de tabaquismo. MATERIAL E MÉTODO: Se seleccionó una muestra aleatoria, representativa de 2.967 escolares de educación básica y media de la Región Metropolitana de Chile, proporcional de acuerdo al curso(IV, VI, y VIII año básico y I y IV año medio), sexo, tipo de colegio y área geográfica. La prevalencia de tabaquismo se determinó mediante un cuestionario autoadministrado. El nivel socioeconómico(NSE) se midió por medio del método de Graffar modificado, midiéndose además, las condiciones familiares, la exposición a medios de comunicación de masas y factores psicosociales. El rendimiento escolar se determinó mediante un test de castellano y matemáticas, al mismo tiempo que se registraron otras variables educacionales. El análisis estadístico incluyó análisis de varianza, test de la t de Student y test de Scheffe para comparación de medias, correlación, regresión múltiple stepwise, chi-cuadrado y la metodología del enfoque de riesgo de OPS/OMS, para el cálculo del riesgo relativo simple (RR). RESULTADOS: La prevalencia de tabaquismo (10,6%) aumentó significativamente con la edad, de 1,3% en los escolares menores de 13 años, a 15,4% y 36,9%, en los adolescentes entre 13-15 años y ³ 16 años, respectivamente (p< 0,001), a la vez que fue mayor en los escolares de sexo femenino. El grado de placer(r=0,499 p<0,001), el grado de rebeldía(r=0,124 p<0,0001), el grado de recreación familiar (r=-0,131 p<0,0001) y el porcentaje de asistencia al colegio(r=-0,118 p< 0,0001), fueron las variables independientes con el mayor poder explicatorio en la varianza del tabaquismo (r²= 0,2860), pero el grado de placer fue la variable con el mayor poder explicatorio en la varianza explicada (89,2%) y con el mayor RR (34,3). El impacto relativo de las variables independientes sobre el tabaquismo experimentó diferencias de acuerdo a la edad, sexo y NSE. CONCLUSIONES: Nuestros resultados han demonstrado que el grado de placer, el grado de rebeldía, el grado de recreación familiar y el porcentaje de asistencia al colegio, fueron las variables independientes que mayormente contribuyeron a explicar el tabaquismo. Estos hallazgos podrían ser de utilidad para las políticas educacionales y de salud focalizadas a la población escolar, con el objeto de prevenir este importante factor de riesgo para la salud de la población.

Extraction of hemoglobin with calixarenes and biocatalysis in organic media of the complex with pseudoactivity of peroxidase

The present work involves the use of p-tert-butylcalix[4,6,8]arene carboxylic acid derivatives ((t)Butyl[4,6,8]CH2COOH) for selective extraction of hemoglobin. All three calixarenes extracted hemoglobin into the organic phase, exhibiting extraction parameters higher than 0.90. Evaluation of the solvent accessible positively charged amino acid side chains of hemoglobin (PDB entry 1XZ2) revealed that there are 8 arginine, 44 lysine and 30 histidine residues on the protein surface which may be involved in the interactions with the calixarene molecules. The hemoglobin-(t)Butyl[6]CH2COOH complex had pseudoperoxidase activity which catalysed the oxidation of syringaldazine in the presence of hydrogen peroxide in organic medium containing chloroform. The effect of pH, protein and substrate concentrations on biocatalysis was investigated using the hemoglobin-(t)Butyl[6]CH2COOH complex. This complex exhibited the highest specific activity of 9.92 x 10(-2) U mg protein(-1) at an initial pH of 7.5 in organic medium. Apparent kinetic parameters (V'(max), K'(m), k'(cat) and k'(cat)/K'(m)) for the pseudoperoxidase activity were determined in organic media for different pH values from a Michaelis-Menten plot. Furthermore, the stability of the protein-calixarene complex was investigated for different initial pH values and half-life (t(1/2)) values were obtained in the range of 1.96 and 2.64 days. Hemoglobin-calixarene complex present in organic medium was recovered in fresh aqueous solutions at alkaline pH, with a recovery of pseudoperoxidase activity of over 100%. These results strongly suggest that the use of calixarene derivatives is an alternative technique for protein extraction and solubilisation in organic media for biocatalysis.

Thinking over b‐learning strategy: the MIPO model approach

This article describes the main research results in a new methodology, in which the stages and strategies of the technology integration process are identified and described. A set of principles and recommendations are therefore presented. The MIPO model described in this paper is a result of the effort made regarding the understanding of the main success features of good practices, in the web environment, integrated in the information systems/information technology context. The initial model has been created, based on experiences and literature review. After that, it was tested in the information and technology system units at higher school and also adapted as a result of four cycles of an actionresearch work combined with a case study research. The information, concepts and procedures presented here give support to teachers and instructors, instructional designers and planning teams – anyone who wants to develop effective b‐learning instructions.

Para uma reorganização do serviço público de media: responsabilidade social, independência institucional e autonomia editorial no quadro da relação problemática entre o Estado e o mercado

O debate em torno dos media de serviço público aborda com frequência, e por boas razões, o quão justificável é o envolvimento público no mercado dos meios de comunicação social e − para aqueles que o aceitem − a natureza do seu papel, do seu campo de operações e dos conteúdos e serviços disponibilizados. Estas questões definem o campo de batalha central, onde se joga o destino e o papel dos media de serviço público. Aos assuntos de governança é dispensada menor atenção. Se aceitarmos que os media públicos desempenham um papel importante nas esferas cultural e política das sociedades europeias, como deverá o fornecimento dos seus serviços ser organizado? Como se conseguirá encontrar o delicado equilíbrio entre controlo público, responsabilização e autonomia editorial? Estas questões, que constituirão o objecto deste capítulo, são muitas vezes consideradas um subtema burocrático por pessoas com interesses específicos e conhecimentos especializados, como é o caso de funcionários públicos nas autoridades de regulação, advogados em grupos privados de comunicação, académicos, ou gestores/administradores de media públicos. No entanto, a temática deve atrair agora maior atenção, uma vez que as questões de governação podem constituir o novo – e mais subtil – campo de batalha, no qual os grupos privados de comunicação procuram novas oportunidades, após verificarem que o seu ataque à própria existência dos seus congéneres públicos não se traduziu numa vitória clara.

A new control strategy with saturation effect compensation for an autonomous induction generator drivenby wide speed range turbines

This paper presents a variable speed autonomous squirrel cage generator excited by a current-controlled voltage source inverter to be used in stand-alone micro-hydro power plants. The paper proposes a system control strategy aiming to properly excite the machine as well as to achieve the load voltage control. A feed-forward control sets the appropriate generator flux by taking into account the actual speed and the desired load voltage. A load voltage control loop is used to adjust the generated active power in order to sustain the load voltage at a reference value. The control system is based on a rotor flux oriented vector control technique which takes into account the machine saturation effect. The proposed control strategy and the adopted system models were validated both by numerical simulation and by experimental results obtained from a laboratory prototype. Results covering the prototype start-up, as well as its steady-state and dynamical behavior are presented. (C) 2011 Elsevier Ltd. All rights reserved.

A strategy to extend reactive distillation column performance under catalyst deactivation

This work addresses the effects of catalyst deactivation and investigates methods to reduce their impact on the reactive distillation columns performance. The use of variable feed quality and reboil ratio are investigated using a rigorous dynamic model developed in gPROMS and applied to an illustrative example, i.e., the olefin metathesis system, wherein 2-pentene reacts to form 2-butene and 3-hexene. Three designs and different strategies on column energy supply to tackle catalyst deactivation are investigated and the results compared.

Fast optimum-predictive control and capacitor voltage balancing strategy for bipolar back-to-back NPC converters in high-voltage direct current transmission systems

Multilevel power converters have been introduced as the solution for high-power high-voltage switching applications where they have well-known advantages. Recently, full back-to-back connected multilevel neutral point diode clamped converters (NPC converter) have been used inhigh-voltage direct current (HVDC) transmission systems. Bipolar-connected back-to-back NPC converters have advantages in long-distance HVDCtransmission systems over the full back-to-back connection, but greater difficulty to balance the dc capacitor voltage divider on both sending and receiving end NPC converters. This study shows that power flow control and dc capacitor voltage balancing are feasible using fast optimum-predictive-based controllers in HVDC systems using bipolar back-to-back-connected five-level NPC multilevel converters. For both converter sides, the control strategytakes in account active and reactive power, which establishes ac grid currents in both ends, and guarantees the balancing of dc bus capacitor voltages inboth NPC converters. Additionally, the semiconductor switching frequency is minimised to reduce switching losses. The performance and robustness of the new fast predictive control strategy, and its capability to solve the DC capacitor voltage balancing problem of bipolar-connected back-to-back NPCconverters are evaluated.