Modelos de comportamiento seccional de hormigón armado ajustados a ensayos mediante algoritmos metaheurísticos

[SPA] En la tesis doctoral "Modelos de comportamiento seccional de hormigón armado ajustados a ensayos mediante algoritmos metaheurísticos" se proponen unas expresiones de comportamiento seccional capaces de proporcionar aspectos relativos a los estados de plastificación y último de secciones rectangulares de hormigón armado, como son el momento, la curvatura y el giro. Dichas expresiones se obtienen calibrando unas expresiones previamente propuestas en la literatura científica con ensayos experimentales correspondientes a vigas y pilares de sección rectangular. En el proceso de calibración se emplean técnicas de optimización basadas en algoritmos metaheurísticos.[ENG] Modelling concrete structures requires the implementation of numerical models capable of reproducing the nonlinearity of this problem adequately. In particular, the seismic behaviour of these structures requires the application of different types of models, such as models of sectional behaviour, hysteresis models and global models, being the interaction between them essential to simulate the problem in an integral way. Seismic analysis of structures is a really time-consuming process, so that the models involved need to be accurate and efficient from the point of view of computing time. Therefore, it is important to obtain simple expressions that adequately reproduce the yield and ultimate behaviour of reinforced concrete sections, which is necessary to define the properties of the plastic hinges generated in the structure when acting the seismic load. Obtaining these expressions involves proper calibration with experimental tests. In particular, if these expressions must be calibrated by an extensive database, specific numerical procedures are required, such as those based on optimization techniques, in order to achieve an optimum adjustment between the values offered by the expressions and the experimental results. In this thesis, a database composed by more than 1000 experimental tests has been analysed and a set of tests is selected such that meet with seismic and construction requirements listed in the main construction codes; several empirical expressions relating to yielding and ultimate state of rectangular reinforced concrete sections have been calibrated; and the expressions obtained are implemented in the nonlinear analysis of several reinforced concrete frames, comparing the results obtained with different methods.Universidad Politécnica de CartagenaPrograma de doctorado en Medio Ambiente y Minería Sostenibl

Circles within spirals, wheels within wheels; Body rotation facilitates critical insights into animal behavioural ecology

How animals behave is fundamental to enhancing their lifetime fitness, so defining how animals move in space and time relates to many ecological questions, including resource selection, activity budgets and animal movement networks. Historically, animal behaviour and movement has been defined by direct observation, however recent advancements in biotelemetry have revolutionised how we now assess behaviour, particularly allowing animals to be monitored when they cannot be seen. Studies now pair ‘convectional’ radio telemetries with motion sensors to facilitate more detailed investigations of animal space-use. Motion sensitive tags (containing e.g., accelerometers and magnetometers) provide precise data on body movements which characterise behaviour, and this has been exemplified in extensive studies using accelerometery data, which has been linked to space-use defined by GPS. Conversely, consideration of body rotation (particularly change in yaw) is virtually absent within the biologging literature, even though various scales of yaw rotation can reveal important patterns in behaviour and movement, with animal heading being a fundamental component characterising space-use. This thesis explores animal body angles, particularly about the yaw axis, for elucidating animal movement ecology. I used five model species (a reptile, a mammal and three birds) to demonstrate the value of assessing body rotation for investigating fine-scale movement-specific behaviours. As part of this, I advanced the ‘dead-reckoning’ method, where fine-scale animal movement between temporally poorly resolved GPS fixes can be deduced using heading vectors and speed. I addressed many issues with this protocol, highlighting errors and potential solutions but was able to show how this approach leads to insights into many difficult-to-study animal behaviours. These ranged from elucidating how and where lions cross supposedly impermeable man-made barriers to examining how penguins react to tidal currents and then navigate their way to their nests far from the sea in colonies enclosed within thick vegetation

Forest landscapes and global change. New frontiers in management, conservation and restoration. Proceedings of the IUFRO Landscape Ecology Working Group International Conference

This volume contains the contributions of numerous participants at the IUFRO Landscape Ecology Working Group International Conference, which took place in Bragança, Portugal, from 21 to 24 of September 2010. The conference was dedicated to the theme Forest Landscapes and Global Change - New Frontiers in Management, Conservation and Restoration. The 128 papers included in this book follow the structure and topics of the conference. Sections 1 to 8 include papers relative to presentations in 18 thematic oral and two poster sessions. Section 9 is devoted to a wide-range of landscape ecology fields covered in the 12 symposia of the conference. The Proceedings of the IUFRO Landscape Ecology Working Group International Conference register the growth of scientific interest in forest landscape patterns and processes, and the recognition of the role of landscape ecology in the advancement of science and management, particularly within the context of emerging physical, social and political drivers of change, which influence forest systems and the services they provide. We believe that these papers, together with the presentations and debate which took place during the IUFRO Landscape Ecology Working Group International Conference – Bragança 2010, will definitively contribute to the advancement of landscape ecology and science in general. For their additional effort and commitment, we thank all the participants in the conference for leaving this record of their work, thoughts and science