A chaos analysis of the dry bulk shipping market

Finding low-dimensional chaos is a relevant issue as it could allow short-term reliable forecasting. However, the existence of chaos in shipping freight rates remains an open and out-standing matter as previous research used methodology that can produce misleading results. Using daily data, this paper aims to unveil the nonlinear dynamics of the Baltic Dry Index that has been proposed as a measure of the shipping rates for certain raw materials. We tested for the existence of nonlinearity and low-dimensional chaos. We have also examined the chaotic dynamics throughout three sub-sampling periods, which have been determined by the volatility pattern of the series. For this purpose, from a comprehensive view we apply several metric and topological techniques, including the most suitable methods for noisy time series analysis. The proposed methodology considers the characteristics of chaotic time series, such as nonlinearity, determinism, sensitivity to initial conditions, fractal dimension and recurrence. Although there is strong evidence of a nonlinear structure, a chaotic and, therefore, deterministic behavior cannot be assumed during the whole or the three periods considered. Our findings indicate that the generalized autoregressive conditional heteroscedastic (GARCH) model and exponential GARCH (EGARCH) model explain a significant part of the nonlinear structure that is found in the dry bulk shipping freight market

Evaluating nonlinearity and chaos in maritime traffic.

RESUMEN. En este estudio se aborda la existencia de patrones no lineales y el comportamiento caótico de la demanda de transporte marítimo de mercancía general en contenedores en los puertos españoles, utilizando datos de frecuencia mensual para el periodo 1992-2013. Para ello en primer lugar, se aplica la metodología Box-Jenkins para el análisis de series temporales como paso preparatorio con el objetivo de eliminar la ependencia lineal. Posteriormente con el fin de evaluar la no linealidad y el comportamiento determinista se utilizan el método BDS y el test de Lyapunov, respectivamente. Los resultados obtenidos son especialmente relevantes para la modelización y predicción del tráfico marítimo de contenedores y en definitiva, para el diseño y evaluación de políticas públicas relacionadas con la planificación de las inversiones portuarias. Se concluye que existe evidencia de la existencia de no linealidad en la dinámica subyacente de la serie de tráfico de contenedores aunque ésta no es compatible con un comportamiento caótico.ABSTRACT. This paper addresses the existence of nonlinear dynamics and chaotic behavior in the Spanish maritime transport services using monthly temporarily data for the period 1992- 2013. For this purpose in first instance the Box-Jenkins approach for time series analysis as a preparatory step in order to remove linear dependence. Afterwards nonlinearity and chaotic behavior are evaluated by means of the BDS and the Lyapunov test respectively. The results are especially relevant for modeling and prediction of maritime container traffic and for the design and evaluation of public policies related to the planning and management of port investments. Our findings suggest that there is evidence for the existence of nonlinearity in the underlying dynamics of the number of traffic containers that is not compatible with a chaotic behavior

Evaluating productivity and efficiency of Spanish airports after air transport liberalization

RESUMEN. Desde la década de los noventa, se han desarrollado diversos procesos -liberalización del transporte aéreo, globalización, irrupción de las compañías aéreas de bajo coste- que han tenido implicaciones relevantes sobre el sistema aeroportuario español. Este artículo estudia los cambios acaecidos en la productividad y eficiencia técnica de los aeropuertos españoles entre 1992 y 2012. Para ello se aplica la metodología denominada Análisis Envolvente de Datos (DEA) que permite la estimación de índices Malmquist de productividad y su posterior descomposición en indicadores de eficiencia técnica y cambio tecnológico. Los resultados obtenidos muestran que los aeropuertos españoles han experimentado durante el periodo analizado un moderado incremento de la productividad total de los factores que es imputable prácticamente en exclusiva al crecimiento de la eficiencia técnica.ABSTRACT. Since the 1990s, several significant events i.e. liberalization of air transport, globalization, economic crisis and low-cost carrier presence, have produced considerable effects on the Spanish airports. This paper studies the changes in both technical efficiency and total factor productivity of Spanish airports that have happened in 1992-2012. To this end, we have applied a Data Envelopment Analysis (DEA) methodology to estimate Malmquist indices of productivity change that have the advantage of being able to break down as a combination of the technological change and the technical efficiency. Results show that Spanish airports have experienced during the period analyzed an increment in the total factor productivity which is mainly due to technical efficiency change

Testing for nonlinearity and chaos in liquid bulk shipping

ABSTRACT: Modelling and forecasting port traffic are of major importance for the shipping industry. Existence of chaos implies that while long term forecasting is vain, reliable short-term forecasting would be possible. The objective of this research is to uncover the nonlinear dynamics and chaotic behavior of the liquid bulk cargo shipping, using monthly data from January 1992 to March 2013 for the Spanish seaports. For this purpose, in first instance we remove any linear dependence by means of the Box-Jenkins approach. Afterwards we analyzed the existence of nonlinearity and chaotic behavior by applying the BDS and the Lyapunov test respectively. Our findings suggest that although there has been found a dominant nonlinear structure underlying the dynamics of the liquid bulk traffic, determinism cannot be assumed and hence chaos cannot be inferred. These results are especially relevant for modeling and forecasting of maritime traffic, specifically for liquid bulk cargo, and for the design and evaluation of public policies related to the investment planning and management of port system

Economia Social, Crise Econômica e Reestruturação do Estado de Bem-Estar: Caso espanhol

Objective: This article aims to establish a historical and current link between the evolution of the welfare state, the social economy and economic crises. From this general objective, another more concrete objective can be deduced: to draw the links between the economic recession in 2008 and the consequences on the welfare state in Spain. Methodology: this research is carried out with secondary sources, through the literature review of theoretical aspects of the welfare state and the social economy. The consequences of the recession have been analyzed, examining different areas of action corresponding to the main areas that make up social policy, mainly housing, including various indicators —foreclosures, evictions or the GDP of the Autonomous Communities—.Objetivo: el presente artículo pretende establecer una vinculación histórica y actual entre la evolución del Estado de bienestar, la economía social y las crisis económicas. De este objetivo general se deduce otro objetivo más concreto: trazar los vínculos entre el estadillo de la recesión económica iniciada en 2008 y las consecuencias en el Estado de bienestar en España. Metodología: esta investigación se realiza con fuentes secundarias, mediante la revisión bibliográfica de aspectos teóricos del Estado del bienestar y la Economía Social. Se han analizado las consecuencias derivadas de la recesión, examinándose diferentes ámbitos de actuación correspondientes a las principales áreas que conforman la política social, fundamentalmente la vivienda, incluyéndose diversos indicadores —ejecuciones hipotecarias, desahucios o el PIB de las Comunidades Autónomas—. Para ello se ha trabajado a partir de una revisión bibliográfica de autores de referencia, revistas especializadas, sitios web y datos procedentes de fuentes gubernamentales (INE, Banco de España, entre otras). Resultados: el resultado advertido es que el Estado del bienestar ha experimentado transformaciones en sus interpretaciones y puntos de vista marcados por los heterogéneos contextos políticos económicos y sociales que ha vivido en los últimos años. En el presente, no es resultado de un único factor sino de un compendio de escenarios políticos, sociales y laborales que traspasan nuestras fronteras debido a la globalización. Conclusiones: se puede determinar que el futuro implica, necesariamente, una reestructuración del Estado del Bienestar dentro de las líneas generales de actuación que defiende la economía social.Objetivo: Este artigo tem como objetivo estabelecer um vínculo histórico e atual entre a evolução do estado social, a economia social e as crises econômicas. Deste objetivo geral, outro objetivo mais concreto pode ser deduzido: estabelecer os vínculos entre a recessão econômica em 2008 e as conseqüências para o estado social da Espanha. Metodologia: esta pesquisa é realizada com fontes secundárias, através da revisão da literatura sobre aspectos teóricos do estado de bem-estar e da economia social. As consequências da recessão foram analisadas, examinando diferentes áreas de ação correspondentes às principais áreas que compõem a política social, principalmente a habitação, incluindo vários indicadores - execuções duma hipoteca, despejos ou o PIB das Comunidades Autônomas -

Agent-based virtual organization architecture

The purpose of this paper is to present the applicability of THOMAS, an architecture specially designed to model agent-based virtual organizations, in the development of a multiagent system for managing and planning routes for clients in a mall. In order to build virtual organizations, THOMAS offers mechanisms to take into account their structure, behaviour, dynamic, norms and environment. Moreover, one of the primary characteristics of the THOMAS architecture is the use of agents with reasoning and planning capabilities. These agents can perform a dynamic reorganization when they detect changes in the environment. The proposed architecture is composed of a set of related modules that are appropriate for developing systems in highly volatile environments similar to the one presented in this study. This paper presents THOMAS as well as the results obtained after having applied the system to a case study

Multilayer OMIC data in medullary thyroid carcinoma identifies the STAT3 pathway as a potential therapeutic target in RETM918T tumors

Purpose: Medullary thyroid carcinoma (MTC) is a rare disease with few genetic drivers, and the etiology specific to each known susceptibility mutation remains unknown. Exploiting multilayer genomic data, we focused our interest on the role of aberrant DNA methylation in MTC development.Experimental Design: We performed genome-wide DNA methylation profiling assessing more than 27,000 CpGs in the largest MTC series reported to date, comprising 48 molecularly characterized tumors. mRNA and miRNA expression data were available for 33 and 31 tumors, respectively. Two human MTC cell lines and 101 paraffin-embedded MTCs were used for validation.Results: The most distinctive methylome was observed for RETM918T-related tumors. Integration of methylation data with mRNA and miRNA expression data identified genes negatively regulated by promoter methylation. These in silico findings were confirmed in vitro for PLCB2, DKK4, MMP20, and miR-10a, -30a, and -200c. The mutation-specific aberrant methylation of PLCB2, DKK4, and MMP20 was validated in 25 independent MTCs by bisulfite pyrosequencing. The methylome and transcriptome data underscored JAK/Stat pathway involvement in RETM918T MTCs. Immunostaining [immunohistochemistry (IHC)] for the active form of signaling effector STAT3 was performed in a series of 101 MTCs. As expected, positive IHC was associated with RETM918T-bearing tumors (P < 0.02). Pharmacologic inhibition of STAT3 activity increased the sensitivity to vandetanib of the RETM918T-positive MTC cell line, MZ-CRC-1.Conclusions: Multilayer OMIC data analysis uncovered methylation hallmarks in genetically defined MTCs and revealed JAK/Stat signaling effector STAT3 as a potential therapeutic target for the treatment of RETM918T MTCs.This work was supported by the Fondo de Investigaciones Sanitarias (FIS) project PI14/00240 and the Comunidad de Madrid (Grant S2011/BMD-2328 TIRONET) to MR. LI-P is supported by the Centro de Investigacion Biomédica en Red de Enfermedades Raras (CIBERER). VM was supported by a predoctoral fellowship from the "la Caixa"/CNIO international PhD programme. CM-C is supported by a postdoctoral fellowship from the Fundación AECC

Temporal bounded reasoning in a dynamic case based planning agent for industrial environments

This paper presents a planning model integrated within a TB-CBP-BDI real-time intelligent agent that provides special abilities for planning in a predictable time, which makes its use especially appropriate in systems where certain temporal constraints must be satisfied. The proposed TB-CBP-BDI real-time agent is the core of a multi-agent system that manages security issues in industrial environments, where time constraints are a key factor. The proposed planning model facilitates the automatic temporal bounded reorganization of tasks to provide the system with adaptation abilities to the changes that occur in the environment. The planning mechanism focuses on optimizing industrial and manufacturing processes, specifically the tasks performed by the available security entities in these environments. Additionally, several Ambient Intelligence technologies such as QR-CODES, GPS, Wi-Fi and HSDPA are used to develop the intelligent environment that was tested and analyzed in this study

Improving the Tracing System in PANGEA Using the TRAMMAS Model

This paper presents the integration of the tracing model TRAMMAS in an agent platform called PANGEA. This platform allows to developed multiagent systems modeled as Virtual Organizations. The concepts of roles, organizations and norms are fully supported by the platform assuring flexibility and scalability. Before TRAMMAS, this platform uses a Sniffer Agent to trace the information reducing its scalability as a centralized mechanism. TRAMMAS proposes the use of event tracing in multiagent systems, as an indirect interaction and coordination mechanism to improve the amount and quality of the information that agents can perceive in order to fulfill their goals more efficiently. Moreover, the event tracing system can help reducing the amount of unnecessary information

Etiología de las infecciones del tracto urinario y sensibilidad de los uropatógenos a los antimicrobianos

El tratamiento antibiótico de la infección urinaria en el adulto se realiza habitualmente de forma empírica, siendo excepcional la realización de urocultivo. La elección del antibiótico se sustenta en los resultados de las series de casos publicadas (urocultivos positivos), de las que se extrae el perfil etiológico más probable y la sensibilidad esperada. Presentamos los resultados de los estudios publicados en los últimos años, detallando las diferencias en función de la procedencia y características de los pacientes, y su tendencia temporal. En las infecciones urinarias de vías bajas sin factores de riesgo el tratamiento debe cubrir fundamentalmenteEscherichia coli. Sin embargo, en las infecciones urinarias complicadas o con factores de riesgo la información clínico-epidemiológica disponible no permite la elección empírica segura en ausencia de urocultivo. Asimismo, llama la atención el descenso de la sensibilidad deE. coli a diversos antibióticos, con grandes variaciones geográficas; el descenso de actividad de las fluoroquinolonas podría comprometer en un futuro su uso empírico