Synchronization and Diversity in Business Cycles: A Network Approach Applied to the European Union

This paper analyses synchronization in business cycles across the European Union (EU) since 1989. We include both old and new European Union members and countries which are currently negotiating accession, as well as potential European Union members. Our methodological approach is based on the correlation matrix and the networks within, which allows us to summarize the individual interaction and co-movement, while also capturing the existing heterogeneity of connectivity within the European economic system. The results indicate that the synchronization of the old EU countries remained stable until the current financial crisis. Additionally, the synchronization of the new and potential members has approached to the old EU members although we observe the existence of different synchronization levels and dynamics in output growth in single countries as well as in groups of countries. Some countries have achieved an important degree of co-movement (such as the Baltic Republics, Hungary, Slovenia and Iceland), while others have experienced reduced synchronization, or even desynchronization (such as Romania, Bulgaria and even Greece and Ireland).Business cycle synchronization, European Union countries, EU candidates, complex systems, network topology.

Measuring Globalization: A hierarchical network approach

This paper investigates the business cycle co-movement across countries and regions since the middle of the last century as a measure for quantifying the ongoing globalization process of the world economy. Our methodological approach is based on analysis of a correlation matrix and the networks it contains. Such an approach summarizes the interaction and interdependence of all elements and it represents a more accurate measure of the global interdependence involved in the economic system. Our results show (1) that the dynamics of globalization has been more driven by synchronization in regional growth patterns than by the synchronization of the world economy as a whole in contrast with other empirical works and (2) that world crisis periods increase dramatically the global co movement in the world economy.Globalization, regionalism, correlation matrix, clustering, synchronization

Co-movements in commodity prices: a note based on network analysis

This paper analyses co-movements in a wide group of commodity prices during the time period 1992-2010. Our methodological approach is based on the correlation matrix and the networks inside. Through this approach we are able to summarize global interaction and interdependence, capturing the existing heterogeneity in the degrees of synchronization between commodity prices. Our results produce two main findings: (a) we do not observe a persistent increase in the degree of co-movement of the commodity prices in our time sample, however from mid-2008 to the end of 2009 co-movements almost doubled when compared with the average correlation; (b) we observe three groups of commodities which have exhibited similar price dynamics (metals, oil and grains and oilseeds) and which have increased their degree of co-movement during the sampled period. These results suggest that speculation and uncertainty are drivers of the sharp slump in commodity prices synchronization.commodity prices, co-movement, hierarchy and topology, networks, complex systems

The effect of rippling on the mechanical properties of graphene

Graphene is the stiffest material known so far but, due to its one-atom thickness, it is also very bendable. Consequently, free-standing graphene exhibit ripples that has major effects on its elastic properties. Here we will summarize three experiments where the influence of rippling is essential to address the results. Firstly, we observed that atomic vacancies lessen the negative thermal expansion coefficient of free-standing graphene. We also observed an increase of the Young's modulus with global applied strain and with the introduction of small density defects that we attributed to the decrease of rippling. Here, we will focus on a surprising feature observed in the data: the experiments consistently indicate that only the rippling with wavelengths between 5-10nm influences the mechanics of graphene. The rippling responsible of the negative TEC and anomalous elasticity is thought to be dynamic, i.e. flexural phonons. However, flexural phonons with these wavelengths should have minor effects on the mechanics of graphene, therefore other mechanisms must be considered to address our observations. We propose static ripples as one of the key elements to correctly understand the thermomechanics of graphene and suggest that rippling arises naturally due to a competition of symmetry breaking and anharmonic fluctuations

Quality of life and demographic growth in the Santa Fe Metropolitan Area

Las desiguales condiciones de vida en que se desenvuelve un conjunto poblacional urbano potencia problemas sociales y según sea la dinámica demográfica, requiere diferentes demandas y desafíos a las administraciones gubernamentales fundamentalmente de orden local a fin de reducir desigualdades. El Aglomerado Gran Santa Fe (AGSF) se caracteriza por desbalances en términos de calidad de vida y al mismo tiempo si bien presenta un crecimiento general bajo, éste no es homogéneo en toda la extensión del aglomerado. El presente artículo describe las etapas de elaboración de un índice de calidad de vida del AGSF mediante el cruce de datos aportados por variables socioeconómicas y ambientales que emanan de diversas fuentes de información y que fueron agrupadas en dimensiones ‘publicas’ y ‘privadas’ de los hogares, a fin de evaluar la incidencia específica de estos dos aspectos en la determinación de la calidad de vida. Otra cuestión destacada del trabajo radica en el análisis del vínculo entre crecimiento demográfico y calidad de vida, sin ánimo de establecer una relación directa causaefecto, a fin de cotejar tendencias generales de expansión o retracción de los grupos poblacionales con diferente calidad de vida, y su correspondiente implantación espacial. Los resultados demuestran aspectos positivos de la propuesta metodológica seguida, pudiendo ser de utilidad la estrategia de tratar por separado las ‘dimensiones’ de la calidad de vida para el estudio de ámbitos urbanos.The unequal living conditions in an urban population generate social problems, and according to demographic dynamics, requires different demands and challenges to government administrations, mainly municipal, to reduce imbalances. The Santa Fe Metropolitan Area (AGSF) is characterized by imbalances in terms of quality of life and at the same time while having a low overall growth, this is not uniform throughout the all the metropolitan area. This article describes the stages of elaboration of an index of quality of life for the AGSF by crossing data provided by socioeconomic and environmental variables that emanate from various sources of information and were grouped into 'public' dimensions and 'private' of homes, in order to assess the specific effect of these two aspects in determining the quality of life. Another issue of the work lies in the analysis of the link between population growth and quality of life, without seeking to establish a relation direct cause – effect, to compare general trends of expansion or contraction of population groups with different quality of life, and its corresponding spatial implementation. The results show positive aspects of the methodology used, and may be useful the strategy to deal separately with the "dimensions" of the quality of life in order to further knowledge of the behavior of these aspects and their interrelations, in the study of urban spaces.Fil: Gomez, Nestor Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; ArgentinaFil: Velázquez, Guillermo Ángel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Instituto de Geografía, Historia y Ciencias Sociales. Universidad Nacional del Centro de la Provincia de Buenos Aires. Instituto de Geografía, Historia y Ciencias Sociales; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires; Argentin

Actuator and sensor fault estimation based on a proportional-integral quasi-LPV observer with inexact scheduling parameters

© 2019. ElsevierThis paper presents a method for actuator and sensor fault estimation based on a proportional-integral observer (PIO) for a class of nonlinear system described by a polytopic quasi-linear parameter varying (qLPV) mathematical model. Contrarily to the traditional approach, which considers measurable or unmeasurable scheduling parameters, this work proposes a methodology that considers inexact scheduling parameters. This condition is present in many physical systems where the scheduling parameters can be affected by noise, offsets, calibration errors, and other factors that have a negative impact on the measurements. A H8 performance criterion is considered in the design in order to guarantee robustness against sensor noise, disturbance, and inexact scheduling parameters. Then, a set of linear matrix inequalities (LMIs) is derived by the use of a quadratic Lyapunov function. The solution of the LMI guarantees asymptotic stability of the PIO. Finally, the performance and applicability of the proposed method are illustrated through a numerical experiment in a nonlinear system.Peer ReviewedPostprint (author's final draft

Modeling time and valuation in structured argumentation frameworks

Temporal Argumentation Frameworks (TAF) represent a recent extension of Dung's abstract argumentation frameworks that consider the temporal availability of arguments. In a TAF, arguments are valid during specific time intervals, called availability intervals, while the attack relation of the framework remains static and permanent in time; thus, in general, when identifying the set of acceptable arguments, the outcome associated with a TAF will vary in time. We introduce an extension of TAF, called Extended Temporal Argumentation Framework (E-TAF), adding the capability of modeling the temporal availability of attacks among arguments, thus modeling special features of arguments varying over time and the possibility that attacks are only available in a given time interval. E-TAF will be enriched by considering Structured Abstract Argumentation, using Dynamic Argumentation Frameworks. The resulting framework, E-TAF∗, provides a suitable model for different time-dependent issues satisfying properties and equivalence results that permit to contrast the expressivity of E-TAF and E-TAF∗ with argumentation based on abstract frameworks. Thus, the main contribution here is to provide an enhanced framework for modeling special features of argumentation varying over time, which are relevant in many real-world situations. The proposal aims at advancing in the integration of time and valuation in the context of argumentation systems as well.Fil: Budan, Maximiliano Celmo David. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación; Argentina. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Exactas y Tecnologías. Departamento de Matemática; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; ArgentinaFil: Gomez Lucero, Mauro Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación; ArgentinaFil: Chesñevar, Carlos Iván. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional de Santiago del Estero. Facultad de Ciencias Exactas y Tecnologías. Departamento de Matemática; Argentina. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación; ArgentinaFil: Simari, Guillermo Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca; Argentina. Universidad Nacional del Sur. Departamento de Ciencias e Ingeniería de la Computación; Argentin

Inverting angiogenesis with interstitial flow and chemokine matrix-binding affinity

The molecular signaling pathways that orchestrate angiogenesis have been widely studied, but the role of biophysical cues has received less attention. Interstitial flow is unavoidable in vivo, and has been shown to dramatically change the neovascular patterns, but the mechanisms by which flow regulates angiogenesis remain poorly understood. Here, we study the complex interactions between interstitial flow and the affinity for matrix binding of different chemokine isoforms. Using a computational model, we find that changing the matrix affinity of the chemokine isoform can invert the effect of interstitial flow on angiogenesis—from preferential growth in the direction of the flow when the chemokine is initially matrix-bound to preferential flow against the flow when it is unbound. Although fluid forces signal endothelial cells directly, our data suggests a mechanism for the inversion based on biotransport arguments only, and offers a potential explanation for experimental results in which interstitial flow produced preferential vessel growth with and against the flow. Our results point to a particularly intricate effect of interstitial flow on angiogenesis in the tumor microenvironment, where the vessel network geometry and the interstitial flow patterns are complex.Peer ReviewedPostprint (published version

The youngest South American rhynchocephalian, a survivor of the K/Pg extinction

Rhynchocephalian lepidosaurs, though once widespread worldwide, are represented today only by the tuatara (Sphenodon) of New Zealand. After their apparent early Cretaceous extinction in Laurasia, they survived in southern continents. In South America, they are represented by different lineages of Late Cretaceous eupropalinal forms until their disappearance by the Cretaceous/Palaeogene (K/Pg) boundary. We describe here the only unambiguous Palaeogene rhynchocephalian from South America; this new taxon is a younger species of the otherwise Late Cretaceous genus Kawasphenodon. Phylogenetic analysis confirms the allocation of the genus to the clade Opisthodontia. The new form from the Palaeogene of Central Patagonia is much smaller than Kawasphenodon expectatus from the Late Cretaceous of Northern Patagonia. The new species shows that at least one group of rhynchocephalians not related to the extant Sphenodon survived in South America beyond the K/Pg extinction event. Furthermore, it adds to other trans-K/Pg ectotherm tetrapod taxa, suggesting that the end-Cretaceous extinction affected Patagonia more benignly than the Laurasian landmasses.Fil: Apesteguía, Sebastián. Universidad Maimónides. Area de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Gomez, Raul Orencio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Rougier, Guillermo W.. University Of Kentucky; Estados Unido