Exponential localization of singular vectors in spatiotemporal chaos

In a dynamical system the singular vector (SV) indicates which perturbation will exhibit maximal growth after a time interval $\tau$. We show that in systems with spatiotemporal chaos the SV exponentially localizes in space. Under a suitable transformation, the SV can be described in terms of the Kardar-Parisi-Zhang equation with periodic noise. A scaling argument allows us to deduce a universal power law $\tau^{-\gamma}$ for the localization of the SV. Moreover the same exponent $\gamma$ characterizes the finite-$\tau$ deviation of the Lyapunov exponent in excellent agreement with simulations. Our results may help improving existing forecasting techniques.Comment: 5 page

Impactos del Cambio Climático en la Generación de Energía Renovable y Evaluación de Escenarios de Generación Energética

Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Económicas y Empresariales, leída el 26-04-2022This Thesis was titled Climate Change Impacts on Renewable Energy Generation and Energy Generation Scenarios.Climate change is attributed, among other factors, to greenhouse gas emissions produced by the energy sector (including the transport). At the same time, climate change is expected to affect this sector by changing the availability of resources, altering its enabling conditions and transforming demand patterns. This thesis addresses climate change impacts on renewable generation and electricity demand by providing an overview of the most relevant transformations projected in literature and by developing methodologies and quantitative analysis to ascertain the specific infuence in three case studies.The first and second chapters are focus on estimating climate change impacts in wind and photovoltaic generation in specific plants. Both provide physical and economic projections of expected changes, along with conclusions for the development of energy policies. The last chapter delves into how climate change and the scenarios proposed to curb it, can affect the demand for electricity in a region, due to the expected changes in the generation infrastructure and changes on the demand side such as a high penetration of electric vehicles...Esta Tesis se tituló Impactos del Cambio Climático en la Generación de Energía Renovable y Escenarios de Generación de Energía. El cambio climático se atribuye, entre otras variables, a las emisiones de gases de efecto invernadero producidas por el sector energético (incluyendo el transporte). Al mismo tiempo, el cambio climático se espera que pueda afectar a este sector cambiando la disponibilidad de sus recursos, alterando sus condiciones habilitantes y transformando los patrones de la demanda. Esta Tesis aborda los impactos del cambio climático en la generación renovable y cambios en el comportamiento de la demanda de electricidad, proporcionando una introducción a las transformaciones más relevantes proyectadas por la literatura y desarrollando metodologías y análisis cuantitativos que determinan el impacto específico en tres casos de estudio. El primer y el segundo capítulo se centran en determinar los cambios esperados en la generación eólica y fotovoltaica en plantas específicas, con especial atención en el calentamiento global. Ambos proporcionan proyecciones físicas y económicas de los cambios esperados, junto con conclusiones para el desarrollo de políticas energéticas. El último capítulo profundiza en cómo el cambio climático y los escenarios propuestos para frenarlo, pueden afectar a la demanda de electricidad de una región, debido a los cambios esperados en las infraestructuras de generación y en cambios por el lado de la demanda como sería una elevada penetración de los vehículos eléctricos...Fac. de Ciencias Económicas y EmpresarialesTRUEunpu

The Environmental Attitudes and Behaviours of European Golf Tourists

Environmental attitudes and behaviours have received relatively little attention in golf tourism, compared to other tourism research areas. Golf tourism provides products and services based on nature, and they should focus on the environment. Golf has become increasingly important in the development of European tourism within the last decade. Moreover, golf is one of the primary motivations for European tourists in the sports tourism sector. This study is based on a sample of 431 golf tourists, from different nationalities, who visit Andalusia, Spain. This research examines the relationship between environmental attitudes and behavioural intentions for three subsamples of European nationalities: British, German, and Spanish. This relationship was corroborated in the three subsamples. However, the national citizenship of European golf tourists was not a moderator effect on the relationship between environmental attitudes and behavioural intentions

Logarithmic bred vectors in spatiotemporal chaos: structure and growth

Bred vectors are a type of finite perturbation used in prediction studies of atmospheric models that exhibit spatially extended chaos. We study the structure, spatial correlations, and the growth- rates of logarithmic bred vectors (which are constructed by using a given norm). We find that, after a suitable transformation, logarithmic bred vectors are roughly piecewise copies of the leading Lyapunov vector. This fact allows us to deduce a scaling law for the bred vector growth rate as a function of their amplitude. In addition, we relate growth rates with the spectrum of Lyapunov exponents corresponding to the most expanding directions. We illustrate our results with simulations of the Lorenz '96 model.Comment: 8 pages, 8 figure

Heterogeneous responses to effective tax enforcement : evidence from Spanish firms

Este documento investiga los efectos de supervisar los rastros de información generados por las actividades de las empresas con el objetivo de mejorar el cumplimiento de sus obligaciones tributarias. A partir de la variación cuasiexperimental proporcionada por la Unidad de Grandes Contribuyentes (UGC) existente en España, contrastamos empíricamente las predicciones teóricas relativas a las respuestas de las empresas ante un incremento del esfuerzo de supervisión tributario. Las empresas que facturan más de 6 millones de euros son revisadas por una UGC que dispone de más recursos para verifi car las transacciones reportadas por las empresas. Utilizando los estados contables de casi el universo de empresas españolas para el periodo 1999-2007, encontramos una concentración sustancial de empresas justo debajo del umbral de la UGC. En media, estimamos que las empresas que se concentran en el umbral reducen su ingresos reportados en 101.000 euros (1,7 % de su ingreso total) para evitar caer en el régimen de elevado control tributario. Ajustando por la existencia de costes de evasión soportados por las empresas, estimamos que la empresa marginal que decide situarse en el umbral reduce sus ingresos reportados en 593.000 euros (9,9 %). La respuesta es débil en sectores en los que la mayoría de las ventas se realizan al consumidor fi nal (venta al por menor, restauración) y fuerte en sectores que mayoritariamente venden bienes intermedios a otras empresas (distribución mayorista, manufactura). Este resultado indica que el esfuerzo de supervisión ejercido por la autoridad tributaria y la trazabilidad de la información reportada por las empresas son complementarios, y ambos necesarios para un control tributario efectivo. Finalmente, la evidencia presentada sugiere la declaración inadecuada de gastos asociados a la adquisición de materiales y de los costes laborales para evadir ..This paper investigates the effects of monitoring the information trails generated by firms’ activities in order to improve tax compliance. We use quasi-experimental variation provided by a Large Taxpayers Unit (LTU) in Spain to empirically test the theoretical predictions on firms’ responses to an increase in monitoring effort. Firms with more than €6 million in reported revenue are monitored by the LTU, which devotes more resources to verifying the transactions reported by those fi rms. Using fi nancial statements from practically the entire universe of Spanish firms for the period 1999-2007, we find substantial bunching of firms just below the LTU threshold. On average, we estimate that bunchers reduce their reported revenue by €101,000 (1.7% of total revenue) to avoid falling in the high enforcement regime. Adjusting for resource costs of evasion faced by firms, we estimate that the marginal bunching firm reduces its reported revenue by up to €593,000 (9.9%). The response is weak in sectors where most sales are made to final consumers (retail, restaurants) and strong in sectors where fi rms sell intermediate goods to other businesses (wholesale, manufacturing). This result suggests that the monitoring effort by the tax authorities and the traceability of the information reported by firms are complements, and both are necessary for effective tax enforcement. Finally, we provide suggestive evidence that firms under low monitoring effort also misreport their material and labour expenditures to evade taxes, even in the presence of third-party reportin

The elasticity of taxable income in Spain: 1999-2014

En este artículo se estudia cómo reacciona la renta gravable de los contribuyentes españoles ante cambios en los tipos marginales del IRPF, utilizando como principal fuente de identifi cación la variación proporcionada por tres grandes reformas del impuesto introducidas a lo largo del período 1999-2014. Las estimaciones más fi ables de la elasticidad de la renta gravable con respecto al tipo marginal neto del impuesto para este período se sitúan en el rango comprendido entre 0,45 y 0,64. Esta elasticidad es cerca de tres veces mayor para los contribuyentes autónomos que para los trabajadores, y es mayor para las rentas procedentes de las actividades económicas que para las rentas del trabajo y del capital. La elasticidad de la renta bruta es menor, entre 0,10 y 0,24, mientras que la elasticidad de algunas deducciones como las de planes de pensiones privados excede de 1. Las estimaciones obtenidas son similares cuando se utiliza una amplia variedad de métodos de estimación y restricciones muestrales, y también son robustas frente a los sesgos potenciales creados por la presencia de reversión a la media y heterogeneidad en las tendencias de renta entre contribuyentes.We study how taxable income responds to changes in marginal tax rates, using as a main source of identifying variation three large reforms to the Spanish personal income tax implemented in the period 1999-2014. The most reliable estimates of the elasticity of taxable income (ETI) with respect to the net-of-tax rate for this period are between 0.45 and 0.64. The ETI is about three times larger for selfemployed taxpayers than for employees, and larger for business income than for labor and capital income. The elasticity of broad income (EBI) is smaller, between 0.10 and 0.24, while the elasticity of some tax deductions such as the one for private pension contributions exceeds one. Our estimates are similar across a variety of estimation methods and sample restrictions, and also robust to potential biases created by mean reversion and heterogeneous income trends

Myocardial trabeculation in embryos of Scyliorhinus canicula (Elasmobranchii, Chondrichthyans)

Currently, three types of ventricular myoarchitecture are recognized in vertebrates, namely compact, spongy (trabeculated) and mixed myocardium. Mixed myocardium, which has been recently proposed as the primitive condition in gnathostomes, is composed of two myocardial layers: an inner trabeculated and an outer compact one. The trabeculation process has been studied in teleosts, showing exclusively spongy myocardium, and mammals and birds, characterized by a compact myocardial ventricular wall. In zebrafish, mouse and chicken embryos, the trabeculae develop as luminal myocardial ridges protruding into the lumen. In mammals and birds, further compactation of trabeculae leads to the formation of a compact layer. The potential mechanisms that may contribute to the formation of the ridges are under discussion and include myocardial proliferation, endocardial invagination, and bending of the entire myocardial layer. However, no description of the development of the mixed myocardium is available. To shed some light on this issue, we have studied the heart development of an elasmobranch species with mixed myocardium, the lesser spotted dogfish (Scyliorhinus canicula; Chondrichthyes), by means of histological and immunohistochemical techniques for light microscopy, semithin sections, scanning electron microscopy and transmission electron microscopy. Our results suggest that in the dogfish the intertrabecular spaces develop by connections between early intramyocardial spaces and the lumen of the ventricle through invaginations of the endocardial line. Chondrichthyans are the earliest diverged lineage of gnathostomes and, consequently, they have the most primitive cardiac design. Although chicken, mouse, and recently zebrafish have been considered powerful vertebrate models to study heart development, we propose that the trabeculation process in the dogfish is representative of the early steps of the ventricular morphogenesis in vertebrates.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.Study supported by grant CGL2017-85090-P and CGL2014-52356-P (Ministerio de Economía y Competitividad), FPU15/03209 (Ministerio de Educación, Cultura y Deporte), FEDER, and Universidad de Málaga

The bulbus arteriosus of the holocephalan heart

El resumen aparece en el Program & Abstracts of the 10th International Congress of Vertebrate Morphology, Barcelona 2013.Anatomical Record, Volume 296, Special Feature — 1: P-074.Previous work has shown that the outflow tract of the elasmobranch heart, namely the cardiac portion intercalated between the ventricle and the ventral aorta, does not consist of a single component, the conus arteriosus, as has classically been assumed, but two, the myocardial conus arteriosus and the non-myocardial bulbus arteriosus. From the evolutionary perspective, knowledge of the anatomy of the cardiac outflow tract of the holocephali is important, as they are the sister group of elasmobranchs. Our aim is to describe the cardiac outflow tract of four holocephalan species, two of them, Chimaera monstrosa and Hydrolagus affinis of the family Chimaeridae, and the other two, Harriotta raleighana and Rhinochimaera atlantica, of the family Rhinochimaeridae. The cardiac outflow tract of the four species consisted of a myocardial conus arteriosus, furnished with valves, and a bulbus arteriosus devoid of cardiac muscle. Both the bulbus and conus are tubular in shape. The length of the bulbus relative to the total length of the outflow tract is somewhat smaller in the rhinochimaerids (15%-19%) than in the chimaerids (19%-23%). The bulbus is covered by epicardium and is crossed by the main coronary artery trunks. Histologically, the bulbus is mainly composed of elastin and collagen, and, to a lesser extent, by smooth muscle. This suggests that in holocephalans, the bulbus actively helps to protect the gill vasculature from exposure to high-pressure pulses of blood. Our results prove that the bulbus arteriosus is common to chondrichthyans. In addition, they support the hypothesis that the cardiac outflow tract consisted of a conus arteriosus and a bulbus arteriosus from the beginning of the jawed vertebrate radiation, contributing to our understanding of the morphological changes that have occurred at the arterial pole of the heart in both actinopterygians and sarcopterygians.Proyecto CGL2010-16417/BOS; Fondos FEDE