L'avifaune de l'habitat fortifié Chalcolitique de Leceia (Oeiras, Portugal)

As escavações conduzidas em Leceia por um de nós (J. L. C.), em continuidade desde 1983, permitiram a recolha de um copioso conjunto de artefactos e de ecofactos, cujo estudo se encontra em curso. Neste estudo apresentam-se os resultados concernantes à avifauna recolhida nas Camadas 4 (do Neolitico final), 3 (do Calcolítico inicial) e 2 (do Calcolítico pleno) no decurso das doze campanhas arqueológicas ali realizadas (até 1994). Identificaram-se onze táxones, sendo de salientar a ocorrência do ganso-patola (Sula bassana) em todas as camadas, do fulmar (Fulmarus glacialis) e do pigargo (Haliaeetus albicilla) na camada 3, que actualmente não frequentam, ao menos usualmente, a região. Do ponto de vista arqueozoológico, discute-se a ocorrência destes e dos restantes taxones identificados - águia (Aquila sp.); perdiz vermelha (Alectoris rufa); galo (?) (cf. Gallus gallus); grou comum (Grus grus); pombo das rochas (Colurnba livia/oenas); corvo (Corvus corax); Alaudidae; e Turdidae - como fontes alimentares ou de matéria-prima para o fabrico de diversos artefactos ósseos, documentados por diversas ocorrências

Strong cosmic censorship: The nonlinear story

A satisfactory formulation of the laws of physics entails that the future evolution of a physical system should be determined from appropriate initial conditions. The existence of Cauchy horizons in solutions of the Einstein field equations is therefore problematic, and expected to be an unstable artifact of General Relativity. This is asserted by the Strong Cosmic Censorship Conjecture, which was recently put into question by an analysis of the linearized equations in the exterior of charged black holes in an expanding universe. Here, we numerically evolve the nonlinear Einstein-Maxwell-scalar field equations with a positive cosmological constant, under spherical symmetry, and provide strong evidence that mass inflation indeed does not occur in the near extremal regime. This shows that nonlinear effects might not suffice to save the Strong Cosmic Censorship Conjecture.Comment: 9 pages, 8 figures. v2: Matches published versio

Bell beaker relationships along the Atlantic coast

Petrographical analysis and archaeological studies realised in southwestern Brittany indicates that most of the Bell Beakers found in this region were produced locally, while a small number of examples are characterised by volcanic rock inclusions and a decoration impressed with a small shell (Donax Vitttus,). The same techniques of decoration have been observes in Portugal, that is why a programme of analysis on some Portuguese Bell Beakers has commenced. The aim of this programme, which began last year, is to specify Bell Beaker circulation mechanisms and exdlange routes along the Atlantic coast and, finally, relationships between littoral, where Bell Beakers are concentrated, and the hinterland. The first results come from the fortified site of Leceia (Oeiras), excavated by J. L. Cardoso

Message in a bottle: energy extraction from bouncing geometries

Quantum gravity phenomenology suggests the interesting possibility that black holes are not eternal. Collapse could be halted by some unknown mechanism, or Hawking radiation might leave behind a regular spacetime. Here we investigate a simple bouncing geometry, with (outer and inner) apparent horizons but no event horizon. We show that the inner horizon blueshifts radiation, which can lead to a gigantic amplification of energy observable from far away regions. Thus, if such phenomena exists in our universe, they can power high-energy bursts at late stages in their lives, when the horizons disappear and spacetime bounces back to a flat geometry.Comment: 5 pages,3 figure

Automatic Vehicle Trajectory Extraction by Aerial Remote Sensing

Research in road users’ behaviour typically depends on detailed observational data availability, particularly if the interest is in driving behaviour modelling. Among this type of data, vehicle trajectories are an important source of information for traffic flow theory, driving behaviour modelling, innovation in traffic management and safety and environmental studies. Recent developments in sensing technologies and image processing algorithms reduced the resources (time and costs) required for detailed traffic data collection, promoting the feasibility of site-based and vehicle-based naturalistic driving observation. For testing the core models of a traffic microsimulation application for safety assessment, vehicle trajectories were collected by remote sensing on a typical Portuguese suburban motorway. Multiple short flights over a stretch of an urban motorway allowed for the collection of several partial vehicle trajectories. In this paper the technical details of each step of the methodology used is presented: image collection, image processing, vehicle identification and vehicle tracking. To collect the images, a high-resolution camera was mounted on an aircraft's gyroscopic platform. The camera was connected to a DGPS for extraction of the camera position and allowed the collection of high resolution images at a low frame rate of 2s. After generic image orthorrectification using the flight details and the terrain model, computer vision techniques were used for fine rectification: the scale-invariant feature transform algorithm was used for detection and description of image features, and the random sample consensus algorithm for feature matching. Vehicle detection was carried out by median-based background subtraction. After the computation of the detected foreground and the shadow detection using a spectral ratio technique, region segmentation was used to identify candidates for vehicle positions. Finally, vehicles were tracked using a k- shortest disjoints paths algorithm. This approach allows for the optimization of an entire set of trajectories against all possible position candidates using motion-based optimization. Besides the importance of a new trajectory dataset that allows the development of new behavioural models and the validation of existing ones, this paper also describes the application of state-of-the-art algorithms and methods that significantly minimize the resources needed for such data collection. Keywords: Vehicle trajectories extraction, Driver behaviour, Remote sensin

A decision-support system to Analyse Customer Satisfaction Applied to a Tourism Transport Service

Due to the perishable nature of tourist products, which impacts supply and demand, the possibility of analysing the relationship between customers’ satisfaction and service quality can contribute to increased revenues. Machine learning techniques allow the analysis of how these services can be improved or developed and how to reach new markets, and look for the emergence of ideas to innovate and improve interaction with the customer. This paper presents a decision-support system for analysing consumer satisfaction, based on consumer feedback from the customer’s experience when transported by a transfer company, in the present case working in the Algarve region, Portugal. The results show how tourists perceive the service and which factors influence their level of satisfaction and sentiment. One of the results revealed that the first impression associated with good news is what creates the most value in the experience, i.e., “first impressions matter”..info:eu-repo/semantics/publishedVersio