SRS-6, almost one year after Hurricane Wilma

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Explicación histórica, socialismo y democracia : La trayectoria de Juan Carlos Portantiero

Uno de los objetivos de este artículo es reconstruir la trayectoria intelectual de Juan Carlos Portantiero en torno a un conjunto limitado de sus intereses: el socialismo y la democracia, en su relación, no por separado, a la vez que ello se vincula con la articulación de una estrategia de explicación histórica y sociológica. La otra veta del artículo analiza las relaciones entre culturas políticas y ciencia social, en particular la cultura de izquierdas y el desarrollo de las ciencias sociales en América Latina. Ello se ha realizado sobre la base de una lectura de casi toda su producción intelectual, tratando de rastrear y mostrar algunas continuidades y cambios o desplazamientos en sus ideas y preocupaciones. Se muestra que Portantiero elabora una estrategia de explicación social sobre la base de Marx, Lenin, Gramsci, Mao hasta fines de los setenta, preocupado por la socialización del poder y, entonces, de la economía. Las dos últimas décadas se concentra en la construcción de las condiciones de consolidación de la democracia, pensada como un régimen que incluya reconocimiento de minorías y funcione para reducir los monopolios económicos y políticos.

SENSORIMOTOR WORKING MEMORY CAPACITY LIMITS

Two novel studies examining the capacity and characteristics of working memory for object weights, experienced through lifting, were completed. Both studies employed visually identical objects of varying weight and focused on memories linking object locations and weights. Whereas numerous studies have examined the capacity of visual working memory, the capacity of sensorimotor memory involved in motor control and object manipulation has not yet been explored. In addition to assessing working memory for object weights using an explicit perceptual test, we also assessed memory for weight using an implicit measure based on motor performance. The vertical lifting or LF and the horizontal GF applied during lifts, measured from force sensors embedded in the object handles, were used to assess participants’ ability to predict object weights. In Experiment 1, participants were presented with sets of 3, 4, 5, 7 or 9 objects. They lifted each object in the set and then repeated this procedure 10 times with the objects lifted either in a fixed or random order. Sensorimotor memory was examined by assessing, as a function of object set size, how lifting forces changed across successive lifts of a given object. The results indicated that force scaling for weight improved across the repetitions of lifts, and was better for smaller set sizes when compared to the larger set sizes, with the latter effect being clearest when objects were lifting in a random order. However, in general the observed force scaling was poorly scaled. In Experiment 2, working memory was examined in two ways: by determining participants’ ability to detect a change in the weight of one of 3 to 6 objects lifted twice, and by simultaneously measuring the fingertip forces applied when lifting the objects. The results showed that, even when presented with 6 objects, participants were extremely accurate in explicitly detecting which object changed weight. In addition, force scaling for object weight, which was generally quite weak, was similar across set sizes. Thus, a capacity limit less than 6 was not found for either the explicit or implicit measures collected.

The Use of Almost Linear Phase IIR filters In DFT Modulated Filter Banks for Communication Systems

This paper is on the use and performance of M-path polyphase Infinite Impulse Response (IIR) filters for channelisation, conventionally where Finite Impulse Response (FIR) filters are preferred. This paper specifically focuses on the Discrete Fourier Transform (DFT) modulated filter banks, which are known to be an efficient choice for channelisation in communication systems. In this paper, the low-pass prototype filter for the DFT filter bank has been implemented using an M-path polyphase IIR filter and we show that the spikes present at the stopband can be avoided by making use of the guardbands between narrowband channels. It will be shown that the channelisation performance will not be affected when polyphase IIR filters are employed instead of their counterparts derived from FIR prototype filters. Detailed complexity and performance analysis of the proposed use will be given in this article.

Reconceptualising International Intervention: Statebuilding, ‘Organic Processes’ and the Limits of Causal Knowledge

This article examines the transformation in the conceptual understanding of international intervention over the last two decades. It suggests that this conceptual shift can be usefully interrogated through its imbrication within broader epistemological shifts highlighting the limits of causal knowledge claims: heuristically framed in this article in terms of the shift from policy interventions within the problematic of causation to those concerned with the management of effects. In this shift, the means and mechanisms of international intervention have been transformed, no longer focused on the universal application of Western causal knowledge through policy interventions but rather on the effects of specific and unique local and organic processes at work in societies themselves. The focus on effects takes the conceptualisation of intervention out of the traditional terminological lexicon of International Relations theory and instead recasts problems in increasingly organicised ways, suggesting that artificial or hubristic attempts at socio-political intervention should be excluded or minimised.