Further results on elementary Lie algebras and Lie A-algebras.

A finite-dimensional Lie algebra L over a field F of characteristic zero is called elementary if each of its subalgebras has trivial Frattini ideal; it is an A-algebra if every nilpotent subalgebra is abelian. This paper is a continuation of the study of these algebras initiated by the authors in a previous paper. If we denote by $\mathcal{A}$, $\mathcal{G}$, $\mathcal{E}$, $\mathcal{L}$, $\Phi$ the classes of A-algebras, almost algebraic algebras, E-algebras, elementary algebras and $\phi$-free algebras respectively, then it is shown that: \mathcal{L} \subset \Phi \subset \mathcal{G} \mathcal{L} \subset \mathcal{A} \subset \mathcal{E} \mathcal{G} \cap \mathcal{A} = \mathcal{L}. It is also shown that if L is a semisimple Lie algebra all of whose minimal parabolic subalgebras are $\phi$-free then L is an A-algebra, and hence elementary. This requires a number of quite delicate properties of parabolic subalgebras. Finally characterisations are given of $E$-algebras and of Lie algebras all of whose proper subalgebras are elementary

Strategies for building pathology reports in an urban rehabilitation process: Project of the Old City Centre of Coimbra

The increasing interest on architectural heritage associated to the recognised building value, at economic, social and cultural levels have stimulated, in the recent decades, the urban rehabilitation and renovation o several cities in Europe. Despite the strategy or method adopted in a city renovation process, its efficiency depends mainly on: type of buildings (structural systems, construction techniques and materials); intervention level (singular buildings, groups of buildings, urban zones, etc.); and, project objective (risk assessment, decision making to support future rehabilitation projects, definition of council maintenance policies, etc.). In what concerns large renovation programs of old city centres, choosing the most adequate approach for inspection, appraisal and diagnosis is a complex task that can determine the success or failure of the project purpose. This paper describes the preparation phase of the inspection of 700 buildings located in the old city centre of Coimbra (Portugal), where a global renovation process is planned for the forthcoming years. In the scope of the renovation and rehabilitation process, the city council contract a complete identification and inspection survey of the buildings, directed on three different domains: (a) architectural typologies, (b) constructive and pathological condition of buildings, and (c) socio-demographic characterisation, of this part of the city. It will be present the check-lists developed and some of the obtained results on point (b), related to roofing systems, and exterior façades. This diagnosis procedure shows that the inspection results quality is quite dependent on the items surveyed for each construction element (roof, façade, internal members, installation efficiency), as well as on the possibility of their correlation for a single building. The adopted method has been applied on 70% of the buildings inspected within the project perimeter. Further treatment of the inspection and appraisal data will allow the developing pathology reports and list repair actions, and estimating rehabilitation costs. It will also help to produce defect level diagrams and seismic building risk maps, but, most important, to improve and guide a renewal strategy and intervention methodology for old buildings

Structural vulnerability of Nepalese Pagoda temples

Nepal is located in one of the most severe earthquake prone areas of the world, lying between collisions of Indian to the Eurasian plate, moving continuously, resulting in frequent devastating earthquakes within this region. Moreover, different authors refer mention that the accumulated slip deficit (central seismic gap) is likely to produce large earthquakes in the future. Also, the analysis of the available information of previous earthquakes indicates the potential damage that can occurs in unreinforced traditional masonry structures in future earthquakes. Most of the Nepalese pagoda temples were erected following very simple rules and construction details to accomplish with seismic resistance requirement, or even without any consideration for seismic resistance, during the period of Malla dynasty (1200-1768). Presently, conservation and restoration of ancient monuments are one of the major concerns in order to preserve our built heritage, transferring it to the future generations. The present paper is devoted to outline particular structural fragility characteristics in the historic Nepalese pagoda temples which affect their seismic performance. Moreover, based on the parametric analysis identified structural weaknesses/fragilities of pagoda topology, the associated traditional building technology and constructional details

Zero-lag long-range synchronization of Hodgkin-Huxley neurons is enhanced by dynamical relaying : poster presentation

Background The synchrony hypothesis postulates that precise temporal synchronization of different pools of neurons conveys information that is not contained in their firing rates. The synchrony hypothesis had been supported by experimental findings demonstrating that millisecond precise synchrony of neuronal oscillations across well separated brain regions plays an essential role in visual perception and other higher cognitive tasks [1]. Albeit, more evidence is being accumulated in favour of its role as a binding mechanism of distributed neural responses, the physical and anatomical substrate for such a dynamic and precise synchrony, especially zero-lag even in the presence of non-negligible delays, remains unclear. Here we propose a simple network motif that naturally accounts for zero-lag synchronization for a wide range of temporal delays [3]. We demonstrate that zero-lag synchronization between two distant neurons or neural populations can be achieved by relaying the dynamics via a third mediating single neuron or population. Methods We simulated the dynamics of two Hodgkin-Huxley neurons that interact with each other via an intermediate third neuron. The synaptic coupling was mediated through alpha-functions. Individual temporal delays of the arrival of pre-synaptic potentials were modelled by a gamma distribution. The strength of the synchronization and the phase-difference between each individual pairs were derived by cross-correlation of the membrane potentials. Results In the regular spiking regime the two outer neurons consistently synchronize with zero phase lag irrespective of the initial conditions. This robust zero-lag synchronization naturally arises as a consequence of the relay and redistribution of the dynamics performed by the central neuron. This result is independent on whether the coupling is excitatory or inhibitory and can be maintained for arbitrarily long time delays (see Fig. 1). Conclusion We have presented a simple and extremely robust network motif able to account for the isochronous synchronization of distant neural elements in a natural way. As opposed to other possible mechanisms of neural synchronization, neither inhibitory coupling, gap junctions nor precise tuning of morphological parameters are required to obtain zero-lag synchronized neuronal oscillation

- CAMBIO DE RÉGIMEN Y SOSTENIBILIDAD A LARGO PLAZO DE LA POLÍTICA FISCAL: EL CASO DE ESPAÑA

In this paper, the Spanish fiscal policy sustainability is tested for the period 1964-1996. The theoretical framework used in this paper draws from Quintos (1995) where a distinction between weak and strong conditions for deficit sustainability is pointed out. From an empirical point of view, new cointegration techniques allowing for structural breaks in the long-run relationships as well as in the cointegration parameters are implemented in order to reach a deeper insight. En este trabajo se contrasta la sostenibilidad de la política fiscal en la economía española para el periodo 1964-1996 utilizando el planteamiento teórico propuesto en Quintos (1995). Desde el punto de vista empírico, la novedad del estudio radica en la utilización de nuevas técnicas de cointegración que recogen la posibilidad de cambios estructurales, tanto en las relaciones de largo plazo como en los parámetros de cointegración.sostenibilidad, política fiscal, cointegración, cambio de régimen sustainability, fiscal policy, cointegration, regimen shifts.

Identifying Volatility Risk Premium from Fixed Income Asian Options

We provide approximation formulas for at-the-money asian option prices to extract volatility risk premium from a joint dataset of bonds and option prices. The dynamic model generates stochastic volatility and a time-varying volatility risk premium, which explicitly depends on the average cross section of bond yields and on the time series behavior of option prices. When estimated using a joint dataset of Brazilian local bonds and asian options, the model generates bond risk premium strongly correlated (89%) with a widely accepted emerging markets benchmark index, and a negative volatility risk premium implying that investors might be using options as insurance in this market. Volatility premium explains a significant portion (32.5%) of bond premium, confirming that options are indeed important to identify risk premium in dynamic term structure models.

Seismic vulnerability assessment of the old city centre of Seixal, Portugal

The seismic vulnerability assessment of old traditional masonry building stocks, in a seismic risk mitigation perspective, is truly essential not only for buildings with recognized historical and patrimonial value, but also, in relation to regular buildings. In this sense, this paper approaches the issue of the seismic vulnerability assessment of masonry buildings through the application of a simplified methodology to building stock of the old city centre of Seixal, Portugal. This methodology is based on a vulnerability index, suitable in the evaluation of damage and in the creation of large scale loss scenarios (economical and human). Over 500 buildings were evaluated in accordance with the referred methodology and the results obtained were then integrated into a Geographical Information System tool. The integration of this kind of vulnerability and loss results into a GIS tool allows that city councils or regional authorities make their decisions based on a global view of the site under analysis, which led to more accurate and faster decisions either in terms of risk mitigation strategies or rehabilitation plans. This tool can also assumes great importance in the construction of safety and rescue plans

Vulnerability assessment of urban building stock: a hierarchic approach

In the last decades the evaluation of the seismic risk are of rising concern, considered essential in the activity and definition of strategy planning and urban management. The evaluation of the seismic vulnerability of the existent building stock in the perspective of the seismic risk mitigation should not be placed only in relation to the isolated buildings of relevant historical and cultural importance, but also, in relation to the agglomerate of buildings in urban centres. The chronological construction process frequently results in characteristic heterogeneity of masonry and wall connection quality. In addition, buildings do not constitute independent units given that they share the mid-walls with adjacent buildings and the façade walls are aligned. This way, as post-seismic observations proved, buildings do not have an independent structural behaviour, but they interact amongst themselves, mainly for horizontal actions and so the structural performance should be studied at the level of the aggregate and not only for each isolated building. In most cases, for masonry structures there is no need for sophisticated dynamic analyses for seismic resistance verification or vulnerability assessment. This is even more relevant when an assessment at the level of a city centre is pursued. In this work, the results of evaluation of the vulnerability will be presented in accordance to three proposed methodologies based on a vulnerability index that consequently allows the evaluation of damage and creation of loss scenarios (economical and human) not only at the level of the building and its façade walls but also at the level of the aggregates. It will be discussed and evaluated the application of the referred methodologies and its integration in an SIG platform

Integral Resonant Control for vibration damping and precise tip-positioning of a single-link flexible manipulator

Peer reviewedPostprin