2,412 research outputs found
Non-Catastrophic Endogenous Growth with Pollution and Abatement
When there are pollution externalities the competitive equilibrium is not Pareto-optimal nor environmentally sustainable even if abatement activities are endogenously decided. In this paper we introduce the possibility of an ecological catastrophe like the one predicted by the global climate change, imposing the constraint of an upper-limit to the pollutants stock. We characterize the socially optimal solution and study conditions for the sustainability of the balanced growth path. We find a trade-off between environmental quality and growth. The rate of growth depends negatively on the weight of environmental care in the utility function and positively on the population growth rate. We show that the emissions reduction recommended in the Kioto protocol is an appropriate policy to avoid the ecological catastrophe and ensure global efficiency and positive long-run growth.Environment, Externalities, Optimal Growth, Ecological Catastrophe, Sustainability.
Closed-Form Solution for a Two-Sector Endogenous Growth Model with two Controls
In this paper we show a method for solving in closed form a particular family of four-dimension non-linear modified Hamiltonian dynamic systems, with two states and two co-states and two co-states, which arises from a two-sector endogenous growth model where the physical capital stock is combined with a renewable natural capital stock as essential inputs for productionNon-Linear Dynamic System, Analytical Solution, Endogenous Growth, Transitional Dynamics
Endogenous Growth, Capital Utilization and Depreciation
We study the one sector model of growth when a linear production technology is combined with adjustment costs and a technology for capital maintenance. Agents are allowed to under-use the installed capital and to vary the depreciation rate. This economy decides endogenously how much resources devotes to the accumulation of new capital and how much to maintenance and repair activities. We find as striking results that the long-run depreciation and capital utilization rates are positively related to the population growth rate, and that both depend negatively on the initial conditions. The long-run growth rate appears positively correlated with the depreciation rate.Maintenance; Depreciation; Capital Utilization; Endogenous Growth
Renewable Natural Resources and Endogenous Growth
We study a two-sector endogenous growth model where a single consumption good is obtained using a renewable resource in combination with physical capital. Both inputs are essential for production and technical substitutes. In this context we analyze the issues of sustainability, long-run and short-run growth as well as convergence, associated with the competitive equilibrium solution trajectories. We show that efficiency, long-run growth and sustainability are both compatible in a natural resource based production economy.Natural Capital, Endogenous Growth, Sustainability, Convergence
Ingesta de alcohol y práctica de actividad físico-deportiva en jóvenes
This study addresses the relationship between two lifestyle factors that have a particular impact on the health of young people, as are the usual practice of leisure-time physical activity and alcohol consumption. Alcohol consumption and leisure-time physical activity was assessed in a sample of 6362 high school students from Compulsory Secondary Education (ESO) and Post-compulsory Secondary Education (ESPO). We used a Pearson Chi-square test to estimate the significant differences between groups. The results show that the patterns of alcohol drinking and leisure-time physical activity of our sample are similar to the rest of the Spanish adolescents. Differences in the consumption of alcohol depending on the quantity and intensity of leisure-time physical activity.El presente estudio aborda la relacion entre dos factores del estilo de vida que tienen una especial incidencia en la salud de los jovenes, como son la practica habitual de ejercicio fisico y el consumo de alcohol. Se evaluaron en 6362 estudiantes de Ensenanza Secundaria Obligatoria (ESO) y Post-obligatoria (ESPO) el consumo de alcohol y la cantidad habitual de actividad fisica. Se realizo un analisis descriptivo e inferencial, con una prueba de estadistico �Ô2 (Chi-cuadrado de Pearson) para estimar las diferencias significativas existentes en los diferentes grupos. Los resultados muestran que los adolescentes estudiados tienen patrones de comportamiento similares al resto de la población española en lo que se refiere a la ingesta habitual de bebidas alcohólicas y práctica de actividad física cotidiana. Existen diferencias en el consumo habitual de alcohol en función de la cantidad e intensidad de actividad físico-deportiva realizada
A high mass progenitor for the Type Ic Supernova 2007gr inferred from its environment
We present an analysis of late-time Hubble Space Telescope Wide Field Camera 3 (WFC3) and Wide Field Planetary Camera 2 (WFPC2) observations of the site of the Type Ic supernova (SN) 2007gr in NGC 1058. The SN is barely recovered in the late-time WFPC2 observations, while a possible detection in the later WFC3 data is debatable. These observations were used to conduct a multiwavelength study of the surrounding stellar population. We fit spatial profiles to a nearby bright source that was previously proposed to be a host cluster. We find that, rather than being an extended cluster, it is consistent with a single point-like object. Fitting stellar models to the observed spectral energy distribution of this source, we conclude it is A1-A3 Yellow Supergiant, possibly corresponding to a star with MZAMS = 40 M⊙. SN 2007gr is situated in a massive star association, with diameter of ≈300 pc. We present a Bayesian scheme to determine the properties of the surrounding massive star population, in conjunction with the Padova isochrones. We find that the stellar population, as observed in either the WFC3 and WFPC2 observations, can be well fit by two age distributions with mean ages: ∼6.3 Myr and ∼50 Myr. The stellar population is clearly dominated by the younger age solution (by factors of 3.5 and 5.7 from the WFPC2 and WFC3 observations, respectively), which corresponds to the lifetime of a star with MZAMS ∼ 30 M⊙. This is strong evidence in favour of the hypothesis that SN 2007gr arose from a massive progenitor star, possibly capable of becoming a Wolf–Rayet star
A Need for a Paradigm Shift in the Spanish Banking Sector? The Evolution from Regional to Multinational Banks in Spain.
Since the approval of Spain¿s 2012 National Budget on March 30, 2012, some doubts and controversies have added up to many fears in the private sector regarding the measures and stimuli that the Spanish government was going to undertake. At the same time, this situation was in some measure aggravated by the financial backlog of many small and medium companies, which are and will continue, in the following years to be completely unable to comply with their financial requirements. In line with Boronat Ombuena¿s (2009a, 2009b, 2010, 2012) requirements in his new approach to finance and private sector liaisons, the purpose of this paper is to analyze the recent years of the credit sector in Spain as well as its direct and mid-term effects that its mergers and acquisitions (M&A) have contributed up to date, and will still produce in the near future. We will take a closer look at the evolution of the banking sector in Spain from 1995 to 2012 through a historically-based methodology, compiling and synthesizing the existing financial and risk market information and analyzing its evolution. We shall observe that in a single year, the total number of savings banks in Spain decreased from 45 to only 15 entities and that the risks the financial system took over these last few years were not equally distributed across the entities, resulting in an advanced foreclosure of the regional savings banks and in a market-share growth for the commercial banking entities. This process has resulted in creating larger entities and, in some cases, a vacuum of regional and local credit entities that in the mid-long term will eventually end up in a representative loss on credit availability. These circumstances call into question the need for a paradigm change and most importantly, new approaches to solve the new challenges that can result in the financial fluidity of the system and the eventual recovery of the economic structure
Generalized Parton Distributions of the Pion
Off-forward structure functions of the pion are investigated in twist-two and
twist-three approximation. A simple model is used for the pion, which allows to
introduce finite size effects, while preserving gauge invariance. Results for
the imaginary parts of the gamma^* pi -> gamma^* pi off-forward amplitude and
of the structure functions are presented. Generalized Callan-Gross relations
are obtained.Comment: 4 pages, 5 figures, LaTeX, uses espcrc2.sty (included), presented at
QCD03 Conference, Montpellier, France, July 200
Mobile Robot Object Recognition through the Synergy of Probabilistic Graphical Models and Semantic Knowledge
J.R. Ruiz-Sarmiento and C. Galindo and J. Gonzalez-Jimenez, Mobile Robot Object Recognition through the Synergy of Probabilistic Graphical Models and Semantic Knowledge, in European Conf. of Artificial Intelligence, CogRob workshop, 2014.Mobile robots intended to perform high-level tasks have to recognize objects in their workspace. In order to increase the success of the recognition process, recent works have studied the use of contextual information. Probabilistic Graphical Models (PGMs) and Semantic Knowledge (SK) are two well-known approaches for dealing with contextual information, although they exhibit some drawbacks: the PGMs complexity exponentially increases with the number of objects in the scene, while SK are unable to handle uncertainty. In this work we combine both approaches to address the object recognition problem. We propose the exploitation of SK to reduce the complexity of the probabilistic inference, while we rely on PGMs to enhance SK with a mechanism to manage uncertainty. The suitability of our method is validated through a set of experiments, in which a mobile robot endowed with a Kinect-like sensor captured 3D data from 25 real environments, achieving a promising result of ~94% of success.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. This work has been funded by the Spanish grant program FPU-MICINN 2010 and the Spanish project "TAROTH: New developments toward a robot at home"
Pareto and Boltzmann-Gibbs behaviors in a deterministic multi-agent system
A deterministic system of interacting agents is considered as a model for
economic dynamics. The dynamics of the system is described by a coupled map
lattice with near neighbor interactions. The evolution of each agent results
from the competition between two factors: the agent's own tendency to grow and
the environmental influence that moderates this growth. Depending on the values
of the parameters that control these factors, the system can display Pareto or
Boltzmann-Gibbs statistical behaviors in its asymptotic dynamical regime. The
regions where these behaviors appear are calculated on the space of parameters
of the system. Other statistical properties, such as the mean wealth, the
standard deviation, and the Gini coefficient characterizing the degree of
equity in the wealth distribution are also calculated on the space of
parameters of the system.Comment: 9 pages, 9 color .eps figures, submitted to Physica
- …