Economic analysis of the Spanish port sector reform during the 1990s

In the matter of port legislation, the nineties was a period of maximum interest in Spain. Two laws enacted in 1992 and 1997, respectively, aimed at increasing the autonomy of individual ports in the management and organization of its activities. Before 1992 two different models of management coexisted in the Spanish port system: autonomous decisionmaking ports and ports controlled in its decision-making by the Central Government. The question we address in this paper is how these legislative changes have affected the evolution of the levels of traffic of the Spanish port system from 1992, date of introduction of the first law, to 2003, date of approval of a third legislative change that remains out of this analysis for lack of sufficient data. We find an important impact of legislative changes on port traffic by way of an estimated econometric model over the 1966–2003 period. We control for the effect of other variables that might have influenced Spanish maritime traffic such as international maritime flows, taken as a proxy of globalization, or gross domestic product, under the hypothesis that maritime transport is a demand derived of economic activity. We provide evidence supporting that greater port autonomy had beneficial effects for the Spanish port system as a whol

Interferometría SAR en las islas Shetland del Sur: modelo numérico de elevaciones de la Isla Decepción

Satellite Synthetic Aperture Radar (SAR) interferometry is a technique that allows the generation of altimetric information. The technique is higly useful in remote areas and this paper shows an application of SAR interferometry in the South Shetland Islands (Antarctica). SAR images obtained by the ERS (European Remote Sensing) satellites of the European Space Agency (ESA) have been processed with an interferometric processor developed by the Departament de Geodinàmica i Geofísica of the Universitat de Barcelona in collaboration with the Institut Cartogràfic de Catalunya

A forced thermal ratchet in a memory heat bath

The present work studies a non-Markovian forced thermal ratchet model on an asymmetric periodic potential. The Brownian dynamics is described by a generalized Langevin equation with an Ornstein-Uhlenbeck-type friction memory kernel. We show that for the case of a time-dependent driving force, also in the form of an Ornstein-Uhlenbeck-like process, an exact expression of the probability current can be derived. We also obtain the behavior of the particle's average rate of flow as a function of the external amplitude force and of the bath temperature when the driving force behaves as a square wave modulation. All our results are compared with those obtained in the Markovian case and we find, fairly remarkably, that in some cases a friction memory kernel results in an enhancement of the curren

Optimal static and dynamic recycling of defective binary devices

The binary Defect Combination Problem consists in finding a fully working subset from a given ensemble of imperfect binary components. We determine the typical properties of the model using methods of statistical mechanics, in particular, the region in the parameter space where there is almost surely at least one fully-working subset. Dynamic recycling of a flux of imperfect binary components leads to zero wastage.Comment: 14 pages, 15 figure

Von Neumann's expanding model on random graphs

Within the framework of Von Neumann's expanding model, we study the maximum growth rate r achievable by an autocatalytic reaction network in which reactions involve a finite (fixed or fluctuating) number D of reagents. r is calculated numerically using a variant of the Minover algorithm, and analytically via the cavity method for disordered systems. As the ratio between the number of reactions and that of reagents increases the system passes from a contracting (r1). These results extend the scenario derived in the fully connected model (D\to\infinity), with the important difference that, generically, larger growth rates are achievable in the expanding phase for finite D and in more diluted networks. Moreover, the range of attainable values of r shrinks as the connectivity increases.Comment: 20 page

Promoting sustainable consumption in Higher Education Institutions through integrative co-creative processes involving relevant stakeholders

The United Nations proposes to ensure a sustainable future for all through the Sustainable Development Goals, assigning a new role to each individual in all sectors of society. Higher Education Institutions are outstanding agents of change, introducing and implementing sustainability in a holistic way, connecting people, and including social and institutional considerations, with students being a key component of change. This study presents a co-creation model to incorporate sustainability in Higher Education Institutions, integrating all members of the university community with a multidisciplinary approach, seeking to address global needs with development tools for new products and services to facilitate the transition of consumers towards responsible consumption. The model aims to analyze the daily consumption pattern of the community at the university, to identify the degree of commitment to sustainability of its members, and to co-create in search of solutions related to responsible consumption and production. This is achieved through five phases of a model, each with specific tasks and objectives based on co-creation processes and tools. As a result, the model enables stakeholders to understand the needs of their community by actively participating within the five phases for developing more democratic solutions and social involvement regarding sustainability issues that can be solved through a co-creative process. The model combines the benefits through ethnographic techniques to discover habits, tools to involve participation, and co-creation to manage complex problems. Future research will focus on the application of the proposed model to more generalist contexts of society, addressing potential challenges due to vertical collaboration and barriers pre-established by society for the adoption of a sustainable lifestyle

Avaluació de nous algorismes per a la creació de camins entre nodes de la xarxa TOR

En este proyecto se presenta un estudio y una implementación sobre estrategias de selección de nodos de la red TOR. Para esto en una primera parte teorica se da a conocer todo lo que comportan las redes anónimas y su implementación en diferentes entornos. A continuación se estudian los requerimientos y la viabilidad del proyecto. Finalmente exponemos el diseño y desarrollo de los distintos algoritmos propuestos juntamente con las pruebas realizadas y las conclusiones a las que se ha llegado.En aquest projecte es presenta un estudi i una implementació sobre estratègies de selecció de nodes de la xarxa TOR. Per això es mostra en una primera part teòrica on es dóna a conèixer tot el que comporten les xarxes anònimes i la seva implantació en diferents entorns. A continuació s'estudien els requeriments i viabilitat del projecte. Finalment exposem el disseny i desenvolupament dels diferents algorismes proposats juntament amb les proves realitzades i les conclusions a les que s'ha arribat.This project presents a study and an implementation on selection strategies TOR network nodes. For this reason, we present in a first theoretical part wich is made known all that behave anonymous networks and it's implementation in different environments. Here we study the requirements and viability of the project. Finally we discuss the design and development of individual proposed algorithms together with the testing results and conclusions we have reached

Trading interactions for topology in scale-free networks

Scale-free networks with topology-dependent interactions are studied. It is shown that the universality classes of critical behavior, which conventionally depend only on topology, can also be explored by tuning the interactions. A mapping, $\gamma' = (\gamma - \mu)/(1-\mu)$, describes how a shift of the standard exponent $\gamma$ of the degree distribution $P(q)$ can absorb the effect of degree-dependent pair interactions $J_{ij} \propto (q_iq_j)^{-\mu}$. Replica technique, cavity method and Monte Carlo simulation support the physical picture suggested by Landau theory for the critical exponents and by the Bethe-Peierls approximation for the critical temperature. The equivalence of topology and interaction holds for equilibrium and non-equilibrium systems, and is illustrated with interdisciplinary applications.Comment: 4 pages, 5 figure

Spin models on random graphs with controlled topologies beyond degree constraints

We study Ising spin models on finitely connected random interaction graphs which are drawn from an ensemble in which not only the degree distribution $p(k)$ can be chosen arbitrarily, but which allows for further fine-tuning of the topology via preferential attachment of edges on the basis of an arbitrary function Q(k,k') of the degrees of the vertices involved. We solve these models using finite connectivity equilibrium replica theory, within the replica symmetric ansatz. In our ensemble of graphs, phase diagrams of the spin system are found to depend no longer only on the chosen degree distribution, but also on the choice made for Q(k,k'). The increased ability to control interaction topology in solvable models beyond prescribing only the degree distribution of the interaction graph enables a more accurate modeling of real-world interacting particle systems by spin systems on suitably defined random graphs.Comment: 21 pages, 4 figures, submitted to J Phys