Intervención internacional a través de los medios de comunicación en sociedades posguerra: Perspectivas a partir de las epistemologías del sur

Over the past two decades, international intervention in post-war settings has strictly followed liberal assumptions and practices. Efforts to build and shape the media in the aftermath of armed conflict are no exception. In setting the foundations for the rule of law, liberal democracy and free market, external actors have (re)defined what constitutes the mediascape – that is, the various spheres of communication within public discourse – and how to (re)construct it. Imprinted with modernity’s tenets and western assumptions about the public space, this approach has understood the mediascape narrowly as limited to traditional, established, liberal media, serving to validate particular actors and processes whilst obscuring, neglecting and shutting off global diversity. Law and technology, this paper argues, are the two main axes through which legitimation and exclusion are effected. A myopic focus on legal and technological aspects of the media reduces a rich space of local discourses, norms and practices to western-like media legislation, training and outlets, narrowing in turn the sites for addressing violence and building peace.Durante las últimas dos décadas, la intervención internacional en contextos posguerra ha seguido estrictamente los supuestos y prácticas liberales. Los esfuerzos para construir y dar forma a los medios de comunicación después de los conflictos armados no son una excepción. Al sentar las bases del estado de derecho, de la democracia liberal y del libre mercado, los actores externos han definido lo que constituye el paisaje mediático, es decir, las diversas esferas de la comunicación en el discurso público y cómo reconstruirlo. Imbuido con los principios de la modernidad y los supuestos occidentales sobre el espacio público, este enfoque ha entendido el panorama mediático estrechamente como limitado a los medios tradicionales, establecidos y liberales, sirviendo para validar actores y procesos particulares mientras oscurece, descuida y cierra la diversidad global. El derecho y la tecnología, sostiene este documento, son los dos ejes principales a través de los cuales se efectúan la legitimación y la exclusión. Un enfoque miope en los aspectos legales y tecnológicos de los medios de comunicación que reduce un rico espacio de discursos, normas y prácticas locales a la legislación, la formación y los medios de comunicación de los medios occidentales, reduciendo a su vez los sitios para abordar la violencia y construir la paz

Analytical Evaluation of Nonlinear Effects on OFDMA Signals

As with other multicarrier modulations, OFDMA signals (Orthogonal Frequency Division Multiple Access) have large envelope fluctuations making them very prone to nonlinear distortion effects. In this paper we study the impact of nonlinear devices on OFDMA signals. We present an analytical characterization of the signals at the output of a nonlinear device that can be used for obtaining the spectral characterization of the transmitted signals, as well as the computation of the nonlinear interference levels on the received signals. It is shown that the power allocated to each user has a key impact on the nonlinear distortion effects. For this reason, we should avoid having low-power and high-power users in adjacent subcarriers. It is also shown that nonlinear distortion levels are lower when just a small fraction of the subcarriers is used (i.e., when the system load is small)

On the Accuracy of the Gaussian Approximation for the Evaluation of Nonlinear Effects in OFDM Signals

The almost Gaussian nature of OFDM (Orthogonal Frequency Division Multiplexing) signals with high number of subcarriers N is widely employed to characterize nonlinearly distorted OFDM signals and to evaluate the corresponding performance. In this paper we study the accuracy of the Gaussian approach when evaluating nonlinear effects in OFDM signals with finite number of subcarriers, showing the strengths and limitations of this approach. It is shown that the decomposition in useful and self-interference components is valid even for a reduced number of subcarriers. The Gaussian approximation of the nonlinear self-interference at the subcarrier level is very accurate provided that N2 is high. However, the nonlinear distortion levels slightly lower than the ones obtained with the Gaussian approximation, with relative errors dropping with 1/N, leading to somewhat pessimistic SIR levels (Signal to Interference Ratio)

The solution of an open problem on semigroup inclusion classes

The semigroup inclusion class $\mathbf{I} = [xyxy = xy; xyz \in \{xywz, xuyz\}]$ is the union of two maximal subvarieties of $\mathbf{GRB} = [xyzxy=xy]$. Monzo ( arXiv:1411.4860 ) described the lattice of semigroup inclusion classes below $\mathbf{I}$ and asked if $\mathbf{I}$ is covered by $\mathbf{GRB}$. Our main result is a characterization of $\mathbf{I}$ which makes it easy to answer Monzo's question in the negative

A Comunicação Estratégica na Saúde: a relação de poder entre a assessoria de imprensa e o jornalismo

O uso da Comunicação Estratégica na saúde é um fenómeno recente, mas em crescimento. Procura-se partilhar informação, conseguir apoio para causas sectoriais, promover a reputação ou responder a pedidos de informação do espaço público, através do uso de técnicas e enunciados estratégicos. De entre esses instrumentos de relação com os públicos da saúde, destacamos a assessoria de imprensa, técnica de Relações Públicas – em si um campo profissional da Comunicação Estratégica – que procura promover a relação das organizações com os media. Ora, porque a assessoria de imprensa em saúde apresenta especificidades que a tornam um estudo de caso relevante no campo da comunicação aplicada (no âmbito da Comunicação Estratégica e no do Jornalismo), apresentaremos uma revisão teórica sobre a temática. Pretendemos pensar as relações entre a Comunicação Estratégica e o Jornalismo, nomeadamente na área da saúde.Este estudo insere-se num projeto de Doutoramento financiado pela FCT (SFRH/BD/86634/2012)info:eu-repo/semantics/publishedVersio

Turbo equalization with cancellation of nonlinear distortion effects for CP-Assisted and Zero-Padded MC-CDMA signals

We consider MC-CDMA schemes, with reduced envelope fluctuations. Both CP-assisted (cyclic prefix) and ZP (zero-padded) MC-CDMA schemes are addressed. We develop turbo FDE (frequency-domain equalization) schemes, combined with cancelation of nonlinear distortion effects. The proposed turbo receivers allow significant performance improvements at low and moderate SNR, even when the transmitted signals have reduced envelope fluctuations

Entre tempos e suspiros. Histórias de emigração em Vieira do Minho

(Excerto) A temática da emigração tem recebido considerável atenção, nas últimas décadas, por parte de investigadores das ciências sociais (Baganha, 1994; Gonçalves e Gonçalves, 1991; Leandro, 2004; Monteiro, 1994; Peixoto, 2004, 2007; Pires, 2003; Ribeiro, 1986; Rocha-Trindade, 1976, 1982, 1985, 1993; Wall, 1984, entre outros). Tal atenção explica-se pelo facto de a mobilidade e a deslocação das populações se terem constituído como assuntos de importância maior, quando se trata de planeamento da sociedade e da definição de políticas públicas. As migrações e as mobilidades mudam de forma ao longo do tempo, adquirindo constantemente outros contornos. Definem-se por outros pressupostos, confrontam-se com outros dilemas e constrangimentos. Não obstante, trata-se inegavelmente de um fenómeno que implica populações, políticas e processos de desenvolvimento, assim como contextos culturais, interesses e motivações individuais. Implica, também, questões de identidade individual e nacional

Joint turbo equalization and cancelation of nonlinear distortion effects in MC-CDMA signals

In this paper, we consider low-PMEPR (Peak-to-Mean Envelope Power Ratio) MC-CDMA (Multicarrier Coded Division Multiple Access) schemes. We develop frequencydomain turbo equalizers combined with an iterative estimation and cancellation of nonlinear distortion effects. Our receivers have relatively low complexity, since they allow FFT-based (Fast Fourier Transform) implementations. The proposed turbo receivers allow significant performance improvements at low and moderate SNR (Signal-to-Noise Ratio), even when a low-PMEPR MC-CDMA transmission is intended