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

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

Correction: An epistatic interaction between the PAX8 and STK17B genes in papillary thyroid cancer susceptibility

El artículo original ha sido publicado: Landa I, Boullosa C, Inglada-Pe´rez L, Sastre-Perona A, Pastor S, et al. (2013) An Epistatic Interaction between the PAX8 and STK17B Genes in Papillary Thyroid Cancer Susceptibility. PLoS ONE 8(9): e74765. doi:10.1371/journal.pone.0074765

Integrative multi-omics analysis identifies a prognostic miRNA signature and a targetable miR-21-3p/TSC2/mTOR axis in metastatic pheochromocytoma/paraganglioma

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors that present variable outcomes. To date, no effective therapies or reliable prognostic markers are available for patients who develop metastatic PPGL (mPPGL). Our aim was to discover robust prognostic markers validated through models, and define specific therapeutic options according to tumor genomic features. : We analyzed three PPGL miRNome datasets (n=443), validated candidate markers and assessed them in serum samples (n=36) to find a metastatic miRNA signature. An integrative study of miRNome, transcriptome and proteome was performed to find miRNA targets, which were further characterized . : A signature of six miRNAs (miR-21-3p, miR-183-5p, miR-182-5p, miR-96-5p, miR-551b-3p, and miR-202-5p) was associated with metastatic risk and time to progression. A higher expression of five of these miRNAs was also detected in PPGL patients' liquid biopsies compared with controls. The combined expression of miR-21-3p/miR-183-5p showed the best power to predict metastasis (AUC=0.804, =4.67·10), and was found associated with pro-metastatic features, such as neuroendocrine-mesenchymal transition phenotype, and increased cell migration rate. A pan-cancer multi-omic integrative study correlated miR-21-3p levels with TSC2 expression, mTOR pathway activation, and a predictive signature for mTOR inhibitor-sensitivity in PPGLs and other cancers. Likewise, we demonstrated a repression and an enhanced rapamycin sensitivity upon miR-21-3p expression. : Our findings support the assessment of miR-21-3p/miR-183-5p, in tumors and liquid biopsies, as biomarkers for risk stratification to improve the PPGL patients' management. We propose miR-21-3p to select mPPGL patients who may benefit from mTOR inhibitors

The Variant rs1867277 in FOXE1 Gene Confers Thyroid Cancer Susceptibility through the Recruitment of USF1/USF2 Transcription Factors

In order to identify genetic factors related to thyroid cancer susceptibility, we adopted a candidate gene approach. We studied tag- and putative functional SNPs in genes involved in thyroid cell differentiation and proliferation, and in genes found to be differentially expressed in thyroid carcinoma. A total of 768 SNPs in 97 genes were genotyped in a Spanish series of 615 cases and 525 controls, the former comprising the largest collection of patients with this pathology from a single population studied to date. SNPs in an LD block spanning the entire FOXE1 gene showed the strongest evidence of association with papillary thyroid carcinoma susceptibility. This association was validated in a second stage of the study that included an independent Italian series of 482 patients and 532 controls. The strongest association results were observed for rs1867277 (OR[per-allele] = 1.49; 95%CI = 1.30–1.70; P = 5.9×10−9). Functional assays of rs1867277 (NM_004473.3:c.−283G>A) within the FOXE1 5′ UTR suggested that this variant affects FOXE1 transcription. DNA-binding assays demonstrated that, exclusively, the sequence containing the A allele recruited the USF1/USF2 transcription factors, while both alleles formed a complex in which DREAM/CREB/αCREM participated. Transfection studies showed an allele-dependent transcriptional regulation of FOXE1. We propose a FOXE1 regulation model dependent on the rs1867277 genotype, indicating that this SNP is a causal variant in thyroid cancer susceptibility. Our results constitute the first functional explanation for an association identified by a GWAS and thereby elucidate a mechanism of thyroid cancer susceptibility. They also attest to the efficacy of candidate gene approaches in the GWAS era

Integrative multi-omics analysis identifies a prognostic miRNA signature and a targetable miR-21-3p/TSC2/ mTOR axis in metastatic pheochromocytoma/ paraganglioma

Rationale: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors that present variable outcomes. To date, no effective therapies or reliable prognostic markers are available for patients who develop metastatic PPGL (mPPGL). Our aim was to discover robust prognostic markers validated through in vitro models, and define specific therapeutic options according to tumor genomic features. Methods: We analyzed three PPGL miRNome datasets (n=443), validated candidate markers and assessed them in serum samples (n=36) to find a metastatic miRNA signature. An integrative study of miRNome, transcriptome and proteome was performed to find miRNA targets, which were further characterized in vitro. Results: A signature of six miRNAs (miR-21-3p, miR-183-5p, miR-182-5p, miR-96-5p, miR-551b-3p, and miR-202-5p) was associated with metastatic risk and time to progression. A higher expression of five of these miRNAs was also detected in PPGL patients’ liquid biopsies compared with controls. The combined expression of miR-21-3p/miR-183-5p showed the best power to predict metastasis (AUC=0.804, P=4.67·10-18), and was found associated in vitro with pro-metastatic features, such as neuroendocrine-mesenchymal transition phenotype, and increased cell migration rate. A pan-cancer multi-omic integrative study correlated miR-21-3p levels with TSC2 expression, mTOR pathway activation, and a predictive signature for mTOR inhibitor-sensitivity in PPGLs and other cancers. Likewise, we demonstrated in vitro a TSC2 repression and an enhanced rapamycin sensitivity upon miR-21-3p expression. Conclusions: Our findings support the assessment of miR-21-3p/miR-183-5p, in tumors and liquid biopsies, as biomarkers for risk stratification to improve the PPGL patients’ management. We propose miR-21-3p to select mPPGL patients who may benefit from mTOR inhibitors

Cinco ensayos sobre complejidad en economía

RESUMEN: Frente a las hipótesis y postulados en que se apoya la teoría económica tradicional, incapaz por si misma de explicar satisfactoriamente determinados comportamientos de los sistemas económicos, surge el concepto de complejidad en la economía, con sus dos vertientes de no linealidad y dinámica caótica, como herramienta que contribuye a explicar la esencia de los hechos económicos anómalos. Esta investigación examina los principales fenómenos económicos, desde la perspectiva de la teoría del caos y los sistemas dinámicos. Para ello se han considerado el comportamiento de las series temporales subyacentes a cinco procesos económicos de especial relevancia en la economía mundial, con el objetivo de obtener información pormenorizada sobre el proceso generador del mismo. Aunque no se ha encontrado ninguna evidencia nítida de un comportamiento caótico, los resultados indican una clara presencia de no linealidad en la mayoría de los procesos.ABSTRACT: As the classic traditional economic theory, seems unable to explain satisfactorily certain behaviors of the economic systems, the concept of complexity in economy arises, including fields as non-linearity and chaotic dynamics, as tools that help to explain the essence of the anomalous economic facts. This research examines the major economic phenomena, from the perspective of the theory of chaos and dynamical systems. For this purpose a total of five economic process of particular relevance in the evolution of the economy are analyzed by means of studying their corresponding time series, in order to obtain detailed information about the process that has generated them. Although no clear evidence of a chaotic behavior has been found, the results indicate a strong evidence of nonlinearity in most of the processes

Estudio estadístico sobre violencia de género

In this paper, we apply both, statistical techniques and data analysis, to the current scenario about violence against women in Europe and specifically in Spain. In particular, we analyze its evolution, visibility, other kind of violence that are classified as gender violence and how other factors might influence, like age, studies level, work situation or prevention assigned budget in it.En este artículo se aplican técnicas de estadística aplicada y análisis de datos a la presentación de un panorama actualizado sobre la violencia de género en Europa y específicamente en España: en particular, se analiza su evolución, visibilización, otros tipos de violencia también clasificada como de género y la influencia de factores como edad, nivel de estudios, situación laboral o presupuesto destinado a su prevenció