Abstract
This paper reports numerical experiments done on a two-parameter family of vector fields which unfold an attracting heteroclinic cycle linking two saddle-foci. We investigated both local and global bifurcations due to symmetry breaking in order to detect either hyperbolic or chaotic dynamics. Although a complete understanding of the corresponding bifurcation diagram and the mechanisms underlying the dynamical changes is still out of reach, using a combination of theoretical tools and computer simulations we have uncovered some complex patterns. We have selected suitable initial conditions to analyze the bifurcation diagrams, and regarding these solutions we have located: (a) an open domain of parameters with regular dynamics; (b) infinitely many parabolic-type curves associated to homoclinic Shilnikov cycles which act as organizing centers; (c) a crisis region related to the destruction or creation of chaotic attractors; (d) a large Lebesgue measure set of parameters where chaotic regimes are dominant, though sinks and chaotic attractors may coexist, and in whose complement we observe shrimps.

Abstract
Phase precession is one of the most well known examples within the temporal coding hypothesis. Here we present a biophysical spiking model for phase precession in hippocampal CA1 which focuses on the interaction between place cells and local inhibitory interneurons. The model's functional block is composed of a place cell (PC) connected with a local inhibitory cell (IC) which is modulated by the population theta rhythm. Both cells receive excitatory inputs from the entorhinal cortex (EC). These inputs are both theta modulated and space modulated. The dynamics of the two neuron types are described by integrate-and-fire models with conductance synapses, and the EC inputs are described using non-homogeneous Poisson processes. Phase precession in our model is caused by increased drive to specific PC/IC pairs when the animal is in their place field. The excitation increases the IC's firing rate, and this modulates the PC's firing rate such that both cells precess relative to theta. Our model implies that phase coding in place cells may not be independent from rate coding. The absence of restrictive connectivity constraints in this model predicts the generation of phase precession in any network with similar architecture and subject to a clocking rhythm, independently of the involvement in spatial tasks.

Abstract
The coastline of Portugal is periodically surveyed by aircraft and the photographs acquired, usually at 1:8000 scale, are used for coastal protection studies. The air photo surveys are expensive and there would be great benefits if they could be replaced by processed images from Earth Observation Satellites. This paper presents the results of an ongoing project, which aims to evaluate the applicability of passive satellite images for coastal protection studies. Images from Landsat TM, SPOT HRVIR and ASTER were used. The initial visual inspection of these images was very encouraging. Two lines of work are currently being pursued - a quantitative and an image exploration approach. The first attempts to estimate the amount of sediments present in the various areas around the sea-breaking zone, by calibrating and atmospherically correcting the satellite images, and to use an established relationship between the amount of suspended sediments and the seawater reflectance. The second approach is to use unsupervised classification and data clustering algorithms to automatically identify different areas in the sea-breaking zone. The current status of each line of work is described and the plans for future work discussed.

Abstract
An agglomerative hierarchical clustering method, which uses both spectral and spatial information for the aggregation decision, is proposed here. The method is suitable for large multispectral images, provided that an unsupervised classification is previously applied. The method is tested on a synthetic image and on a satellite image of the coastal zone.

Abstract
We present a comparative analysis of PARK2 genetic variants based on genotype data from HapMap. We focused our study on the association between missense mutations and all other variations within the same gene to uncover patterns of hidden genetic variation. Alzheimer's disease (AD) and Parkinson's disease (PD) are the main neurodegenerative diseases and represent a growing health concern worldwide, with the increase in the elderly population. Mutations in several genes have been associated with either AD or PD, and the number of novel genetic variants characterized is expanding rapidly with the introduction of next generation sequencing technologies. Most of these variants, however, are of unknown consequences as their effect might be mediated through association with additional mutations. Our results show that significant correlation between genetic variants exists and their co-occurrence might contribute to previously unidentified risk increase.

Abstract
Nicotinamide phosphoribosyltransferase (NAMPT) and nicotinate phosphoribosyltransferase domain containing 1 (NAPRT1) are the main human NAD salvage enzymes. NAD regulates energy metabolism and cell signaling, and the enzymes that control NAD availability are linked to pathologies such as cancer and neurodegeneration. Here, we have screened normal and tumor samples from different tissues and populations of origin for mutations in human NAMPT and NAPRT1, and evaluated their potential pathogenicity. We have identified several novel polymorphisms and showed that NAPRT1 has a greater genetic diversity than NAMPT, where any alteration can have a greater functional impact. Some variants presented different frequencies between normal and tumor samples that were most likely related to their population of origin. The novel mutations described that affect protein structure or expression levels can be functionally relevant and should be considered in a disease context. Particularly, mutations that decrease NAPRT1 expression can predict the usefulness of Nicotinic Acid in tumor treatments with NAMPT inhibitors.