Precautionary savings and the importance of business owners

In this paper, we show the pivotal role business owners play in estimating the importance of the precautionary saving motive. The fact that business owners hold higher-than-average wealth while facing higher income risk than other households leads to a correlation between wealth and labor income risk regardless of whether or not a precautionary motive is important. Using data from the Panel Study of Income Dynamics in the 1980s and the 1990s, we show that within separate samples of both business owners and non-business owners the size of precautionary savings with respect to labor income risk is modest and accounts for less than ten percent of total household wealth. However, pooling together these two groups leads to an artificially high estimate of the importance of precautionary savings. Data from the Survey of Consumer Finances further confirms that precautionary savings account for less than ten percent of total wealth for both business owners and non-business owners. Thus, while a precautionary saving motive exists and affects all households, it does not give rise to high amounts of wealth in the economy, particularly among those households who face the most volatile labor earnings. Klassifizierung: D9

Colección y reinterpretación: La pintura como edición de imágenes

Este trabajo constituye el resultado último de la interacción entre investigación y proceso constructivo mediante la pintura.Los objetivos específicos se resumen en tres ideas principales: reflexionar sobre aspectos que son de especial interés para con un mundo visual contaminado por los medios de comunicación, y su relación con la pintura, analizar y desarrollar los valores conferidos a la imagen y cómo es transferida al campo pictórico, considerar y explicar aquellos puntos determinantes en la obra de mis referentes, para construir una idea globalizada de mi trabajo.Universidad de Sevilla. Grado en Bellas Arte

New effective theories of gravitation and their phenomenological consequences

The objective of this Thesis is to explore Poincaré Gauge theories of gravity and expose some contributions to this field, which are detailed below. Moreover, a novel ultraviolet non-local extension of this theory shall be provided, and it will be shown that it can be ghost- and singularity-free at the linear level. First, we introduce some fundamentals of differential geometry, base of any gravitational theory. We then establish that the affine structure and the metric of the spacetime are not generally related, and that there is no physical reason to impose a certain affine connection to the gravitational theory. We review the importance of gauge symmetries in Physics and construct the quadratic Lagrangian of Poincaré Gauge gravity by requiring that the gravitational theorymust be invariant under local Poincaré transformations. We study the stability of the quadratic Poincaré Gauge Lagrangian, and prove that only the two scalar degrees of freedom (one scalar and one pseudo-scalar) can propagate without introducing pathologies. We provide extensive details on the scalar, pseudo-scalar, and bi-scalar theories. Moreover, we suggest how to extend the quadratic Poincaré Gauge Lagrangian so that more modes can propagate safely. We then proceed to explore some interesting phenomenology of Poincaré Gauge theories. Herein, we calculate how fermionic particles move in spacetimes endowed with a nonsymmetric connection at first order in the WKB approximation. Afterwards, we use this result in a particular black-hole solution of Poincaré Gauge gravity, showing that measurable differences between the trajectories of a fermion and a boson can be observed. Motivated by this fact, we studied the singularity theorems in theories with torsion, to see if this non-geodesical behaviour can lead to the avoidance of singularities. Nevertheless, we prove that this is not possible provided that the conditions for the appearance of black holes of any co-dimension are met. In order to see which kind Black Hole solutions we can expect in Poincaré Gauge theories, we study Birkhoff and no-hair theorems under physically relevant conditions. Finally, we propose an ultraviolet extension of Poincaré Gauge theories by introducing non-local (infinite derivatives) terms into the action, which can ameliorate the singular behaviour at large energies. We find solutions of this theory at the linear level, and prove that such solutions are ghost- and singularity-free. We also find new features that are not present in metric Infinite Derivative Gravity

Precautionary Savings and the Importance of Business Owners

In this paper, we show the pivotal role business owners play in estimating the importance of the precautionary saving motive. Since business owners hold larger amounts of wealth than other households for non-precautionary reasons and also face highly volatile income, they induce a correlation between wealth and income risk regardless of whether or not a precautionary saving motive exists. Using data from the Panel Study of Income Dynamics in the 1980s and the 1990s, we show that among both business owners and non-business owners, the size of precautionary savings with respect to labor income risk is modest and accounts for less than ten percent of total household wealth. However, pooling together the two groups leads to an artificially high estimate of the importance of precautionary savings. New data from the Survey of Consumer Finances further confirms that precautionary savings account for less than ten percent of total wealth for both business owners and non-business owners. Thus, while a precautionary saving motive exists and affects all households, it does not give rise to high amounts of wealth in the economy, particularly among those households who face the most volatile stream of income.

Protocolo para la evaluación del estado ecológico de la red fluvial de Aragón (NE de España) según sus comunidades de macroinvertebrados bentónicos

Rivers play a fundamental role in the biosphere, and to attain a sustainable development it is necessary to evaluate their ecological status, to know how and which human activities affect them, the Water Framework Directive (2000/60/CE) establishes the basic principles for a sustainable water use policy in the EU. With the aim of evaluate the ecological status of the fluvial network of Aragón for the Aragon Government, a protocol for sample taking and analysis was designed to cover two objectives. It had to produce enough precise results and also, it had to allow for space-time comparisons, in accordance with the Directive and international standardization rules. It is based on sampling with Surber net in laminar and turbulent flow, IBMWP index applications, evaluation of the differences in abundance of macroinvertebrates, evaluation of the presence of alien species, assignation of ecological state categories, and cartographic representation. Through this protocol, the ecological status of 140 reaches of the Aragon fluvial network was determined. Abundance corrections were not necessary and only one correction was due to the presence of alien species.Los ríos desempeñan un papel fundamental en la biosfera y para conseguir un desarrollo sostenible es necesario valorar su estado ecológico, comprobando qué actuaciones humanas les afectan y cómo; la Directiva Marco de Aguas (2000/60/CE) establece los principios básicos para una políıtica hídrica sostenible en la UE. Con el objeto de valorar el estado ecológico de la red fluvial aragonesa para el Gobierno de Aragón, se diseñó un protocolo de toma y análisis de muestras que cubriera dos objetivos. Debía producir unos resultados suficientemente precisos y, además, debía permitir las comparaciones espaciotemporales, siguiendo tanto la Directiva como las normas internacionales de estandarización. Está basado en el muestreo con red Surber tanto en flujo laminar como turbulento, aplicación del índice IBMWP, evaluación de las diferencias en la abundancia de macroinvertebrados, valoración de la presencia de especies alóctonas, asignación de categorías de estado ecológico y representación cartográfica. Mediante este protocolo se determinó el estado ecológico de 140 tramos de la red fluvial aragonesa, no siendo necesarias correcciones por abundancia y sólo una corrección por la presencia de especies alóctonas

Comparación del muestreo de macroinvertebrados bentónicos fluviales con muestreador surber y con red manual en ríos de Aragón (NE Península Ibérica)

A la hora de valorar el estado ecológico de los ríos y otras aguas superficiales, la Directiva Marco del Agua (Directiva 2000/60/CE) establece que los métodos utilizados deberán garantizar que la información suministrada sea de calidad y comparabilidad equivalentes; para las comunidades de macroinvertebrados bentónicos fluviales en zonas poco profundas, remite a las normas para la toma de muestras con muestreador Surber y con red manual. Con el fin de comparar estos dos métodos se tomaron 15 estaciones de muestreo distribuidas por la red fluvial de Aragón (NE España), abarcando los distintos tipos de ríos y de estado ecológico existentes en ella. Ambos métodos proporcionaron resultados similares al ser empleados en una misma comunidad, presentando elevados coeficientes de correlación y pendientes cercanas a 1, en cuanto al número de taxones capturados, número de grupos EPT (Ephemeroptera, Plecoptera y Trichoptera), número de taxones que entran a formar parte del índice IBMWP (anteriormente conocido como BMWP'), valor de este índice y del IASPT. Pese a esa elevada correlación, el muestreador Surber presentó una mayor eficiencia media en el número total de taxones capturados que la red manual, recolectando un número ligeramente mayor de taxones, entre ellos de taxones incluidos en el índice IBMWP (dando por tanto un valor del índice un poco más elevado). Se comentan otras ventajas de la utilización del muestreador Surber frente a la red manual, en especial la de permitir estimas cuantitativas.When monitoring the ecological state of rivers and other surface waters, the Water Framework Directive (Directive 2000/60/CE) establishes that the methods used should guarantee that the information given be of an equivalent scientific quality and comparability; for rivers and communities of benthic macroinvertebrates in shallow waters, it remits to the standards for the biological sampling with Surber and hand net. These sampling methods were compared in 15 sites located in the fluvial network of Aragon (NE Spain), including the different types of rivers and ecological states existent in it. Both methods provided similar results when employed with the same community, showing high correlation coefficients and slopes near 1, for number of taxa captured, number of EPT groups (Ephemeroptera, Plecoptera and Trichoptera), number of taxa included in the index IBMWP (formerly known as BMWP'), value of this index and of the IASPT. In spite of this high correlation, the Surber sampler presented a higher average efficiency in the total number of taxa captured than the hand net, capturing a slightly greater number of taxa, taxa included in the IBMWP among them (increasing the value of the index a little). Other advantages of Surber versus hand net are commented, especially that of allowing quantitative samplings

""A Pornish Shadow, Signifying Nothing": A contrastive analysis of Palahniuk's Snuff and Faulkner’s The Sound and the Fury."

RESUMEN El objetivo de este trabajo es el estudio comparativo de la novela modernista canónica de William Faulkner The Sound and the Fury y de la novela del escritor postmodernista norteamericano Chuck Palahniuk Snuff, considerando esta última como una versión pornográfica híper paródica de la primera. El trabajo se centra en el estudio de los personajes de ambas novelas dentro del marco teórico post estructuralista, más concretamente referido a los trabajos de Jacques Derrida, en tanto que los personajes son considerados como signos o símbolos lingüísticos, y a las obras de Judith Butler en referencia al tema de la performatividad del género. A través de este análisis se pretende demostrar cómo ambos autores logran, por medio de sus personajes, desmontar las estructuras ideológicas de la sociedad de su tiempo y abrir el camino a nuevas estructuras donde los habitantes de los márgenes sociales puedan converger en los centros de poder social. Palabras clave: Faulkner, Palahniuk, Derrida, Butler, Pornografía, Parodia, Deconstrucción, Subversión, Performatividad de Género Márgenes, Poder Social. ABSTRACT The aim of this dissertation is the comparative study of William Faulkner’s canonical modernist novel The Sound and the Fury and postmodernist American author Chuck Palahniuk’s Snuff, considering the latter as a pornographic hyper parodic version of the first. The work focuses on a study of the characters in both novels within the post- structuralist framework, specifically referred to the work of Jacques Derrida, insomuch as the characters are regarded as signs or linguistic symbols, and the work of Judith Butler referring to the issue of gender performativity. This analysis is to show how both authors manage, through their characters, to deconstruct the ideological structures of the society of their time and pave the way for new structures where the inhabitants of the social margins may converge in the centers of social power. Key words: Faulkner, Palahniuk, Derrida, Butler, Pornography, Parody, Deconstruction, Gender Performativity, Subversion, Margins, Social Power

Vector stability in quadratic metric-affine theories

In this work we study the stability of the four vector irreducible pieces of the torsion and the nonmetricity tensors in the general quadratic metric-affine Lagrangian in 4 dimensions. This highly constrains the theory reducing the parameter space of the quadratic curvature part from 16 to 5 parameters. We also study the sub-case of Weyl-Cartan gravity, proving that the stability of the vector sector completely fixes the dynamics of the full Lagrangian to just an Einstein-Proca theory or pure General Relativity.Comment: 21 pages, no figures, no table

Revisiting the Stability of Quadratic Poincar\'e Gauge Gravity

Poincar\'e gauge theories provide an approach to gravity based on the gauging of the Poincar\'e group, whose homogeneous part generates curvature while the translational sector gives rise to torsion. In this note we revisit the stability of the widely studied quadratic theories within this framework. We analyse the presence of ghosts without fixing any background by obtaining the relevant interactions in an exact post-Riemannian expansion. We find that the axial sector of the theory exhibits ghostly couplings to the graviton sector that render the theory unstable. Remarkably, imposing the absence of these pathological couplings results in a theory where either the axial sector or the torsion trace becomes a ghost. We conclude that imposing ghost-freedom generically leads to a non-dynamical torsion. We analyse however two special choices of parameters that allow a dynamical scalar in the torsion and obtain the corresponding effective action where the dynamics of the scalar is apparent. These special cases are shown to be equivalent to a generalised Brans-Dicke theory and a Holst Lagrangian with a dynamical Barbero-Immirzi pseudoscalar field respectively. The two sectors can co-exist giving a bi-scalar theory. Finally, we discuss how the ghost nature of the vector sector can be avoided by including additional dimension four operators.Comment: 25 pages, 1 figure. More insight on the bi-scalar theory has been added, including its possible extensions and the coupling with fermions. A clarifying footnote on the Holst term has been introduced. Extended discussion. It matches the version published in EPJ

Uncertainty in recent near-surface wind speed trends: a global reanalysis intercomparison

Reanalysis products have become a tool for wind energy users requiring information about the wind speed long-term variability. These users are sensitive to many aspects of the observational references they employ to estimate the wind resource, such as the mean wind, its seasonality and long-term trends. However, the assessment of the ability of atmospheric reanalyses to reproduce wind speed trends has not been undertaken yet. The wind speed trends have been estimated using the ERA-Interim reanalysis (ERA-I), the second version of the Modern Era Retrospective-Analysis for Research and Applications (MERRA-2) and the Japanese 55-year Reanalysis (JRA-55) for the period 1980–2015. These trends show a strong spatial and seasonal variability with an overall increase of the wind speed over the ocean and a tendency to a decline over land, although important disagreements between the different reanalyses have been found. In particular, the JRA-55 reanalysis produces more intense trends over land than ERA-I and MERRA-2. This can be linked to the negative bias affecting the JRA-55 near-surface wind speeds over land. In all the reanalyses high wind speeds tend to change faster than both low and average wind speeds. The agreement of the wind speed trends at 850 hPa with those found close to the surface suggests that the main driver of the wind speed trends are the changes in large-scale circulation.The authors acknowledge funding support from the COPERNICUS action CLIM4ENERGY-Climate for Energy (C3S 441 Lot 2), the New European Wind Atlas (NEWA) project funded by ERA-NET Plus, Topic FP7 ENERGY.2013.10.1.2, the RESILIENCE (CGL2013–41055-R) project, funded by the Spanish Ministerio de Economía y Competitividad (MINECO), and the FP7 EUPORIAS (GA 308291) and SPECS (GA 308378) projects. Thanks to Daniel Cabezón and Sergio Lozano for their valuable feedback. We acknowledge the s2dverification R-based package (http://cran.rproject. org/web/packages/s2dverification) developers. Finally, we would like to thank Pierre-Antoine Bretonniere, Júlia Giner, Nicolau Manubens and Javier Vegas for their technical support at different stages of this project.Peer ReviewedPostprint (published version