3,884 research outputs found

    Rentabilidad y creación de valor para los accionistas de las empresas españolas y del IBEX 35. 1993-2005

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    En este documento se analiza la evolución del IBEX y de las 72 empresas españolas que cotizaron en bolsa (en el mercado continuo) desde diciembre de 1992 hasta diciembre de 2005. Los apartados del documento son: 1. El IBEX 35. Rentabilidad y creación de valor para los accionistas. 2. Nivel del IBEX 35 necesario para obtener la rentabilidad exigida por los accionistas. 3. Entradas y salidas del IBEX 35. 4. Creación de valor de 72 empresas españolas. 4.1. Aumento del valor para los accionistas. 4.2. Rentabilidad para los accionistas. 4.3. Creación de valor. 4.4. Mayor crecimiento de las empresas grandes hasta el año 2000. 5. Relación de la rentabilidad para los accionistas con el tamaño de las empresas. 6. Relación de la rentabilidad para los accionistas con la rentabilidad del año anterior. 7. Rentabilidad y volatilidad. 8. El ROE no es la rentabilidad para los accionistas. 9. Creación de valor y rentabilidad para los accionistas en 2004. 10. Crisis bursátiles históricas y plazos de recuperación.Rentabilidad; creación de valor; creación valor para accionistas; IBEX 35;

    Rad-hard vertical JFET switch for the HV-MUX system of the ATLAS upgrade Inner Tracker

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    This work presents a new silicon vertical JFET (V-JFET) device, based on the trenched 3D-detector technology developed at IMB-CNM, to be used as switches for the High-Voltage powering scheme of the ATLAS upgrade Inner Tracker. The optimization of the device characteristics is performed by 2D and 3D TCAD simulations. Special attention has been paid to the on-resistance and the switch-off and breakdown voltages to meet the specific requirements of the system. In addition, a set of parameter values has been extracted from the simulated curves to implement a SPICE model of the proposed V-JFET transistor. As these devices are expected to operate under very high radiation conditions during the whole experiment life-time, a study of the radiation damage effects and the expected degradation on the device performance is also presented at the end of the paper.Comment: KEYWORDS: Radiation-hard electronics; Voltage distributions; Large detector systems for particle and astroparticle physics. 9 Pages, 7 Figure

    Monitoring the influence of marine aquaculture on wild fish communities: benefits and limitations of fatty acid profiles

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    Fatty acids (FA) have been applied as indicators of the influence of coastal sea-cage fish farming on wild fish communities in several recent scientific publications. Due to the relatively high conservation of FA composition throughout the food web, they are useful for characterizing trophic relationships. The increasing utilization of vegetable or alternative animal oils in the production of aquafeeds results in cultivated fish exhibiting higher levels of terrestrial FAs in their tissues. As previously reported, wild fish ubiquitously aggregate around fish farms as a consequence of the introduction of new habitat and the easy availability of food—fish farms act as enhanced fish aggregation devices (FADs). The influence of food pellets on the composition of wild fish has been detected in recent studies on salmon, sea bass and sea bream aquaculture, with increased levels of linoleic acid (18:2n-6) and a low n-3/n-6 ratio as clear indicators of the consumption of food pellets from the farms. The potential ecological and physiological effects on wild fish are presently unknown. In the present article, guidelines are proposed for the investigation and use of terrestrial FAs to track the effects of coastal aquaculture on wild fish communities and local fisheries, as well as the benefits or limitations of this technique

    Sources of phenotypic variation of wood density and relationships with mean growth in two eucalyptus species in Argentina

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    Aims of the study: To describe the radial patterns of wood density, and to identify their main sources of variation, and the potential tradeoffs with mean tree growth, in two Eucalyptus species. Area of study: Mesopotamian (Corrientes and Entre Ríos provinces) and Pampean region (Buenos Aires province) of Argentina. Materials and methods: Eucalyptus grandis and Eucalyptus viminalis, growing in genetic trials installed in two sites per species were studied. X-ray wood microdensity profiles were developed from core samples. Each profile was proportionally divided in 10 sections. Mean, maximum, minimum and the standard deviation of wood density, for each section were computed. Mean annual growth was used to study the relationships with wood microdensity variables. A linear mixed-effects model computed the significance of different sources of phenotypic variation. Pearson´s correlation computed the relationships between variables. Main results: The pattern of radial variation in E. grandis showed a decrease in wood density from pith to bark, mainly due to the decrease in minimum wood density, while in E. viminalis, wood density increased towards the outer wood. In both species, the standard deviation of the wood density increased along the radial profile from pith to bark. Significant variation in wood density was explained by site, provenance and clone/family effects. In E. grandis mean, maximum and minimum wood density were negatively correlated with mean growth, whereas in E. viminalis correlations were positive but close to zero. Research highlights: Both the pattern of radial variation of wood density and the relationship between wood density and mean growth were different in the studied Eucalyptus species, and they varied within species depending on the site they were growing and genetic provenance.Fil: Alarcón, Pamela Cecilia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; Argentina.Fil: Alarcón, Pamela Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Fernández, María Elena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Fernández, María Elena. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Agencia de Extensión Rural Tandil; Argentina.Fil: Oberschelp, Gustavo Pedro Javier. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Concordia; Argentina.Fil: Pathauer, Pablo Santiago. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; Argentina.Fil: Martínez Meier, Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; Argentina.Fil: Martínez Meier, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

    Estado de saúde percebido em idosos: desigualdades regionais e sociodemográficas na Espanha

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    OBJECTIVE: To assess regional and sociodemographic differences in self-perceived health status among older adults. METHODS: A face-to-face quality of life survey was conducted in a representative sample of the Spanish population comprising 1,106 non-institutionalized elderly aged 60 or more in 2008. Logistic regression models were used to explain self-perceived health status according to the EuroQol Group Visual Analogue Scale (EQ-VAS). Independent variables included sociodemographic and health characteristics as well as the nomenclature of territorial units for statistics level 1 (NUTS1: group of autonomous regions) and level 2 (NUTS 2: autonomous regions). RESULTS: Younger and better off respondents were more likely to have a positive self-perceived health status. Having no chronic conditions, independence in performing daily living activities and lower level of depression were also associated with positive self-perceived health status. People living in the south of Spain showed a more negative self-perceived health status than those living in other regions. CONCLUSION: The study results point to health inequality among Spanish older adults of lower socioeconomic condition and living in the south of Spain. The analysis by geographic units allows for international cross-regional comparisons.OBJETIVO: Analisar as diferenças regionais e sociodemográficas no estado de saúde percebido por adultos mais velhos. MÉTODOS: Realizou-se um inquérito de qualidade de vida mediante entrevista pessoal com amostra representativa da população espanhola de 1.106 pessoas com 60 e mais anos não institucionalizadas, em 2008. Aplicaram-se modelos de regressão logística para explicar a saúde percebida segundo a escala visual analógica do EuroQol Group (EQ-VAS). As variáveis independentes incluíram características sociodemográficas e de saúde, assim como unidades territoriais estatísticas de nível 1 (grupo de comunidades autônomas) e nível 2 (comunidades autônomas). RESULTADOS: Os participantes dos grupos mais jovens e os que tinham uma melhor situação econômica mostraram maior probabilidade de ter uma percepção positiva da sua saúde. A ausência de problemas crônicos de saúde, a independência para realizar atividades da vida diária e menor nível de depressão também se associaram positivamente à saúde percebida como boa. Os idosos que viviam no sul mostraram uma percepção mais negativa da saúde do que as que vivem noutras regiões. CONCLUSÕES: Os resultados indicam uma desigualdade relativa no estado de saúde dos adultos mais velhos de níveis socioeconômicos inferiores e dos habitantes do sul do país. A análise por unidades territoriais estatísticas permite estabelecer comparações entre regiões em nível internacional.OBJETIVO: Analizar las diferencias regionales y sociodemográficas en el estado de salud percibido por ancianos. MÉTODOS: Se realizó una encuesta de calidad de vida mediante entrevista personal en una muestra representativa de la población española de 1.106 personas con 60 y más años no institucionalizadas en 2008. Se aplicaron modelos de regresión logística para explicar la salud percibida de acuerdo con la escala visual analógica del EuroQol Group (EQ-VAS). Las variables independientes incluyeron características sociodemográficas y de salud, así como unidades territoriales estadísticas de nivel 1 (NUTS1: grupos de comunidades autónomas), y nivel 2 (NUTS2: comunidades autónomas). RESULTADOS: Los participantes de ambos grupos, el de los más jóvenes y los que tenían una mejor situación económica, mostraron mayor probabilidad de tener una percepción positiva de la salud. La ausencia de problemas crónicos de salud, la independencia para desarrollar actividades de la vida diaria y un menor nivel de depresión también se asociaron positivamente a la salud percibida como buena. Los ancianos que vivían en el sur mostraron una percepción más negativa de su salud que aquellos que vivían en otras regiones. CONCLUSIONES: Los resultados muestran desigualdad relativa en el estado de salud de los ancianos de niveles socioeconómicos inferiores y en los habitantes del sur del país. El análisis estadístico por unidades territoriales permite establecer comparaciones entre regiones en nivel internacional

    Change and predictors of quality of life in institutionalized older adults with dementia

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    PURPOSE: This study aims to assess the change in and predictive factors of the quality of life (QoL) of institutionalized older adults with dementia over a 20-month period. METHODS: Information was used from a follow-up study conducted over an average period of 19.61 ± 1.93 months on a sample of 274 institutionalized older adults aged 60 or over, diagnosed with dementia. Two linear regression models were built to predict change in the EQ-5D index and the quality of life in Alzheimer's disease (QOL-AD) scale, taking as independent variables: sociodemographic characteristics and measures of functional ability (Barthel Index), depression in dementia (Cornell Scale), number of chronic health problems, cognitive level (MEC, the Spanish Mini-Mental State Examination) and severity of dementia (Clinical Dementia Rating) at baseline. RESULTS: The majority of the participants were women (81.75 %) with an average age of 84.70 ± 6.51 years, single (78.15 %), with severe dementia and moderate functional dependence. There was a significant decrease on the EQ-5D, EQ-VAS and QOL-AD between baseline and follow-up scores. The main predictors of QoL of the institutionalized older adults with dementia were the number of chronic problems and baseline scores of the QoL measures. CONCLUSIONS: A significant decrease in the QoL of institutionalized older adults was observed over a 20-month period. Results suggest that interventions aimed at reducing the number of chronic medical conditions may have a beneficial effect on older adults' QoL.This study was funded by the CIEN Foundation, Carlos III Institute of Health (Ref. PI 017/09). We would like to thank the help provided by V Blaya-Novakova in language editing. The Spanish Research Group on Quality of Life and Aging is formed by: M. J. Forjaz, ENS-ISCIII; P. Martinez-Martin, CNE-ISCIII; F. Rojo-Perez, CCHS-CSIC; G. Fernandez-Mayoralas, CCHS-CSIC; B. Frades, Fundación CIEN-ISCIII; B. Leon-Salas, Fundación CIEN-ISCIII; Marina Avila, Fundación CIEN-ISCIII; M. E. Prieto-Flores, UNED; S. Martin, EULEN; I. Martinez, EULEN; C. Rodriguez-Blazquez, CNE-ISCIII; A. Ayala, ENS-ISCIII

    Measurement properties of the Community Wellbeing Index in older adults

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    PURPOSE: The international wellbeing index (IWI) consists of two scales, the personal (PWI) and national (NWI) wellbeing indices. The community wellbeing index (CWI) is a new measure of the individual's level of satisfaction with the local place of residence. The main goal of this paper is to validate the CWI in a sample of older adults. METHODS: The IWI was satisfactorily applied to survey the global quality of life of a community sample of 1,106 people aged 60 years and over residing in Spain. The CWI psychometric properties were studied using Rasch analysis. Classic psychometric parameters were also analyzed. RESULTS: Tests of unidimensionality, and exploratory and confirmatory factor analyses, revealed the presence of three subscales: community services, community attachment, and physical and social environment. To achieve adequate model fit of the three subscales to the Rasch model, one item (distribution of wealth) of the initial 11 was removed and item response categories were rescored. The person separation index was 0.82-0.85, indicating a good reliability. All items were free from gender bias. The three subscales displayed satisfactory convergent validity with the PWI and NWI and were able to discriminate between groups with high and low satisfaction with local place of residence. CONCLUSION: The CWI, made up of three subscales, is a valid and reliable measure of subjective wellbeing related to the community as assessed by older adults. Further research with this promising measure should focus on cross-national comparisons.This research was supported by the Spanish Ministry of Science and Innovation (National R&D&I Plan: ref. SEJ2006-15122-C02-00). Prieto-Flores’ position is supported by the Juan de la Cierva program for postdoctoral research, of the Spanish Ministry of Science and Innovation. The Carlos III Institute of Health team is a member of the Consortium for Biomedical Research in Neurodegenerative Diseases (Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas—CIBERNED). The Spanish Research Group on Quality of Life and Aging is made up as follows: (1) at the Carlos III Institute of Health by M. Joao Forjaz, Pablo Martinez-Martin, Maria-Eugenia Prieto-Flores, Belen Frades-Payo, Carmen Rodriguez-Blazquez and Concepcion Delgado-Sanz; and, (2) at the Spanish National Research Council by Gloria Fernandez-Mayoralas, Fermina Rojo-Perez, Karim Ahmed-Mohamed and Raul Lardies-Bosque
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