Abstract
The consequences of regulatory T cell (Treg) inhibition of interleukine 2 secretion is examined by mathematical modelling. We demonstrate that cytokine dependent growth exhibits a quorum T cell population threshold that determines if immune responses develop on activation. Secretion inhibition manipulates the growth dynamics and effectively increases the quorum threshold, i.e. to develop immune responses a higher number of T cells need to be activated. Thus Treg induced secretion inhibition can provide a mechanism for tissue specific regulation of the balance between suppression (control) and immune responses, a balance that can be varied at the local tissue level through the regulation of the local active Treg population size. However, nonspecific inhibition is prone to escape of initially controlled autoimmune T cells through cross reactivity to pathogens and bystander proliferation on unrelated immune responses.

Abstract
The present study intended to assess flexibility of adolescents of both sexes, involving several body regions and articular groups; to compare males with females, to establish, by factor analyses, inter-tests correlations, in order to obtain explanations of the result in original variables and, to verify which principal components, by reduction of the number of correlated variables, are susceptible to better explain variability. The sample is constituted by 52 subjects (28 females and 24 males), aged between 15 and 18 years. Flexibility assessment battery was formed by eight tests: sit and reach (SA), v-sit and reach (V-SA), stand and reach (FTFP), trunk lift (ET), arm-trunk lift (ETB), side bending (FLT-D e FLTE), shoulder stretch (AMAC-D e AMAC-E) and, bend and reach (AAA). The main results showed, in general, a balance in both sexes as far as the ability to perform wide movements is concerned. There is a strong association: 1) among similar technical characteristic tests, which seems there is no need for cumulative use among these tests, and 2) among those tests that have direct effects on laterality, AMAC-D/AMAC-E (except males) and FLT-D/FLT-E. The AAA test did not correlate with any of the performed tests, particularly in males. Factor analyses of principal components (CP) showed the existence of three components in the female group, with eigenvalues higher than 1, explaining 83,2% of total variance, while in the male group four components were necessary to explain 88,8% of total variability. The tests that were more strongly correlated with each one of principal components were: 1) for males: SA, FTFP, V-SA (CP1), FLT-D, FLT-E (CP2), AMAC-D, AAA (CP3), and ETB, ET (CP4); 2) for females: AAA, FLT-E, AMAC-D, AMAC-E, FTFP (CP1), V-SA, SA, FTFP (CP2), and ETB, ET (CP3).

Abstract
In this paper we propose a methodology for automatically retrieving document collections from the web on specific topics and for organizing them and keeping them up-to-date over time, according to user specific persistent information needs. The documents collected are organized according to user specifications and are classified partly by the user and partly automatically. A presentation layer enables the exploration of large sets of documents and, simultaneously, monitors and records user interaction with these document collections. The quality of the system is permanently monitored; the system periodically measures and stores the values of its quality parameters. Using this quality log it is possible to maintain the quality of the resources by triggering procedures aimed at correcting or preventing quality degradation.

Abstract
Typically, search engines are low precision in response to a query, retrieving lots of useless web pages, and missing some other important ones. In this paper, we study the problem of the hierarchical clustering of web pages search results. In particular, we propose an architecture called FUSE [1], a meta-search engine that automatically builds clusters of related web pages embodying one meaning of the query. These clusters are then hierarchically organized and labeled with a phrase representing the key concept of the cluster and the corresponding web documents. The system which is a web-based interface (soon available at wise.di.ubi.pt), introduces some interesting new ideas, such as the pre-selection of the retrieved web pages, the capacity to statistically detect phrases within documents and the representation of documents based on their most relevant key concepts by using web content mining techniques. The final step of the system is supported by a graph-based overlapping clustering algorithm which groups the selected documents into a hierarchy of clusters.

Abstract
Reliability models rarely incorporate the uncertainty that is present in most of the reliability parameters, which is an important limitation for the managers of production system. This paper presents a fuzzy-probabilistic methodology that was developed to analyse production systems. The methodology employs probabilistic theory to represent the stochastic behaviour of the failure and repair processes and fuzzy sets to represent uncertainty in the parameters. This approach is based on a fuzzy reliability analysis from which is possible to obtain the fuzzy downtime function of a system in a given period of analysis. This function is a crucial element to obtain two performance measures: a financial measure (the fuzzy cost concerning failures of a production system) and a quality of service measure (the fuzzy frequency of failure on deliveries), as it will be illustrated in the final part of the paper through a practical example.

Abstract