Search results for "WM"

Immigration, factor endowments and the productive structure of Spanish regions, 1996-2005.

2012

The participation of immigrants in the Spanish labour market has increased from less than 3% in 1996 to more than 13% in 2005. The factor proportion model of production was used to examine the impact of such a large labour supply shock on the industrial structure of Spanish regions. The results confirm that, first, labour endowment differences across regions help to explain the regional patterns of industry specialization. Second, immigrants and natives act as complementary factors in most industries. Third, the importance of immigration is relatively small compared with production technique changes and idiosyncratic industry changes in explaining the overall changes in industrial structure. …

Fluctuacions quàntiques en cavitats òptiques no lineals

2011

Aquesta tesi doctoral tracta sobre alguns aspectes de la generació de llum comprimida en cavitats no lineals tipus Kerr. La llum comprimida és un dels tipus de "llum quàntica", un tipus de llum que posseeix propietats relatives a les fluctuacions en els valors esperats dels seus observables de les què no es pot donar compte si no és mitjançant l'ús de la teoria quàntica de la radiació. L'estat buit del camp electromagnètic posseeix fluctuacions d'acord amb el principi d'incertitud d'Heisenberg. En aquest context, denominem llum comprimida a un tipus de radiació que presenta en algun dels seus observables fluctuacions menors que les corresponents a l'estat buit. Aquest tipus especial de radi…

A Methodology to Detect the Deviations of the Project s Budget Compared to Market Prices

2015

[EN] The budget of a project reflects the cost of the investment needed to build an infrastructure, install a system or acquire new materials or supplies. A well-formulated budget in accordance with market prices, allows contractors to prepare offers according to their technical, economic and financial characteristics. On the other hand, it avoids current philosophies that aim to get the contract at any price. Philosophies subsequently used to point out problems and claims during the execution of the project (contradictory prices, delays, etc.) in order to recover some or the entire economic bid carried out during the tendering. In this paper a simple and fast methodology is developed to ch…

Effect of SMEs' International Experience on Foreign Intensity and Economic Performance: The Mediating Role of Internationally Exploitable Assets and …

2010

In this paper, we study the relationship between the international experience of small and medium-sized enterprises (SMEs) and their economic performance using intangible and financial asset stock, competitive strategy, and international intensity as mediating factors. The RBV provides the theoretical framework to develop a theoretical model postulating that international experience has an indirect effect on foreign growth and economic performance. This model was used to test a sample of 394 Spanish SMEs through the modelization of a structural equations system. Results show that superior economic performance is only achieved by SMEs that can turn the knowledge they gain from international …

Dynamic Finite Element analysis of fractionally damped structural systems in the time domain

2015

Visco-elastic material models with fractional characteristics have been used for several decades. This paper provides a simple methodology for Finite-Element-based dynamic analysis of structural systems with viscosity characterized by fractional derivatives of the strains. In particular, a re-formulation of the well-known Newmark method taking into account fractional derivatives discretized via the Grunwald–Letnikov summation allows the analysis of structural systems using standard Finite Element technology.

Would student's t-GARCH improve VaR estimates?

2005

Dead-time impact on the harmonic distortion and conversion efficiency in a three-phase five-level Cascaded H-Bridge inverter: mathematical formulatio…

2023

To avoid leg short-circuit in inverters, dead time must be introduced on leg gate signals. Dead time affects the inverter output voltage fundamental harmonic amplitude, voltage harmonic distortion and inverter efficiency by introducing additional voltage drops. In this regard, dead time effects have been widely investigated for traditional two-level three-phase voltage source inverters in the literature but not extensively for multilevel topology structures. This paper provides a detailed analysis of dead time impact on the harmonic distortion and efficiency of Cascaded H-Bridges Multilevel Inverters (CHBMIs). For this purpose, a general mathematical formulation to determine voltage drop du…

HETEROGENEITY IN RISK PREFERENCES LEADS TO STOCHASTIC VOLATILITY

2018

This paper studies the price processes of a claim on terminal endowment and of a claim on firm book value when the underlying variables follow a bivariate geometric Brownian motion. If the state-price process is multiplicatively separable into time and endowment functions, our main result shows that firm (endowment) price volatility is stochastic (state-dependent) if, and only if, the endowment function is not a power function. In a pure exchange economy populated by two agents with constant relative risk aversion (CRRA) preferences we confirm the separability, and we show furthermore that firm (endowment) price volatility is stochastic (state-dependent) if, and only if, both agents are he…

Aportaciones de la herpetofauna al conocimiento de la paleobiología y paleoclimatología del tramo temporal Pleistoceno Superior y Holoceno de la Comu…

2022

El periodo Cuaternario se caracteriza climáticamente por la alternancia de fases glaciales e interglaciales, y, asociadas a ellas, importantes fluctuaciones de la línea de costa. Dado que este marco temporal es altamente relevante en el campo de la evolución humana y, por ello, gran parte de su estudio se ha centrado en esta temática; también lo es para entender diversos aspectos de la historia natural de otros grupos de vertebrados, como es el caso de los reptiles y anfibios. Hasta ahora son escasos los estudios del componente herpetológico de las faunas de vertebrados en el este de la península ibérica durante el Pleistoceno Superior y Holoceno, habiéndose centrado fundamentalmente este e…

What Is the Role of Minimally Invasive Mitral Valve Surgery in High-Risk Patients? A Meta-Analysis of Observational Studies

2016

Background. Minimally invasive valve surgery is related to certain better postoperative outcomes. We aimed to assess the role of minimally invasive mitral valve surgery in high-risk patients. Methods. A systematic literature review identified eight studies of which seven fulfilled criteria for metaanalysis. Outcomes for a total of 1,254 patients (731 were conventional standard sternotomy and 523 were minimally invasive mitral valve surgery) were submitted to meta-analysis using random effects modeling. Heterogeneity and subgroup analysis with quality scoring were assessed. The primary end point was early mortality. Secondary end points were intraoperative and postoperative outcomes and long…