[pt] A função simbólica é o aspecto que distingue o mundo humano do mundo animal. A origem do pensar e de todo funcionamento psíquico está no processo de transformação das experiências sensoriais e emocionais, que dominam o início da vida, em símbolos. O símbolo é a unidade elementar que forma o tecido da fantasia e estabelece a relação com o mundo de significados compartilhados. Seus precursores encontram-se nas experiências intersubjetivas iniciais de sintonia afetiva, emergência do senso de eu e de outro e atenção compartilhada, que permitem a constituição das fronteiras psíquicas, fundamentais para o desenvolvimento da capacidade de simbolizar. / [en] The symbolic function is the aspect that makes the difference between the animal world and the human world. The origins of thinking and of psychic functioning are in the process of transforming the sensory and emotional experiences that dominate early life, into symbols. The symbol is the elementary unit that constructs the base of fantasy and permits the child´s entry into the social/ cultural world. Their precursors are in the early intersubjective experiences of affective engagement, the emergence of self-and- other´awareness and attention sharing that permit the construction of psychic frontiers, which are the foundations for the development of the symbolic capacity.

Caching is a widely used technique to improve the scalability of distributed systems. A central issue with caching is maintaining object replicas consistent with their master copies. Large distributed systems, such as the Web, typically deploy heuristic-based consistency mechanisms, which increase delay and place extra load on the servers, while not providing guarantees that cached copies served to clients are up-to-date. Server-driven invalidation has been proposed as an approach to strong cache consistency, but it requires servers to keep track of which objects are cached by which clients. We propose an alternative approach to strong cache consistency, called MONARCH, which does not require servers to maintain per-client state. Our approach builds on a few key observations. Large and popular sites, which attract the majority of the traffic, construct their pages from distinct components with various characteristics. Components may have different content types, change characteristics, and semantics. These components are merged together to produce a monolithic page, and the information about their uniqueness is lost. In our view, pages should serve as containers holding distinct objects with heterogeneous type and change characteristics while preserving the boundaries between these objects. Servers compile object characteristics and information about relationships between containers and embedded objects into explicit object management commands. Servers piggyback these commands onto existing request/response traffic so that client caches can use these commands to make object management decisions. The use of explicit content control commands is a deterministic, rather than heuristic, object management mechanism that gives content providers more control over their content. The deterministic object management with strong cache consistency offered by MONARCH allows content providers to make more of their content cacheable. Furthermore, MONARCH enables content providers to expose internal structure of their pages to clients. We evaluated MONARCH using simulations with content collected from real Web sites. The results show that MONARCH provides strong cache consistency for all objects, even for unpredictably changing ones, and incurs smaller byte and message overhead than heuristic policies. The results also show that as the request arrival rate or the number of clients increases, the amount of server state maintained by MONARCH remains the same while the amount of server state incurred by server invalidation mechanisms grows.