17,409 research outputs found

    Education in values in engineering. Energy for human development and sustainability

    Get PDF
    nergy is central to achieving th e interrelated econo mic, social, and environmental aims of sustaina ble human development. This pa per relates some UPC efforts to introduce the sustainable energy concept in its engineering curricula. The UPC approach is based on the education in values, the critical analysis of the presen t paradigms, and an overview of the global South real ity under a human rights-basis.Peer ReviewedPostprint (published version

    Auto-consistent metallicity and star formation history of the nearest blue compact dwarf galaxy NGC 6789

    Full text link
    We present a detailed auto-consistent study of the nearest blue compact dwarf galaxy NGC 6789 by means of optical and UV archive photometry data and optical long-slit ISIS-WHT spectroscopy observations of the five brightest star-forming knots. The analysis of the spectra in all knots allowed the derivation of ionic chemical abundances of oxygen, nitrogen, sulphur, argon and neon using measures of both the high- and low-excitation electron temperatures, leading to the conclusion that NGC 6789 is chemically homogeneous with low values of the abundance of oxygen in the range 12+log(O/H) = 7.80-7.93, but presenting at the same time higher values of the nitrogen-to-oxygen ratio than expected for its metal regime. We used archival HST/WFPC2 F555W and F814W observations of NGC 6789 to perform a photometric study of the colour-magnitude diagram (CMD) of the resolved stellar populations and derive its star formation history (SFH), which is compatible with the presence of different young and old stellar populations whose metallicities do not necessarily increase with age. We fit the observed optical spectrum in all the five knots using the STARLIGHT code and a combination of single stellar populations following the SFH obtained from the CMD. We compare the resulting stellar masses and the relative fractions of the ionising populations with a non-constrained SFH case. The properties of the younger populations were obtained using CLOUDY photoionisation models, giving similar ages in all the knots in the range 3-6 Myr and the estimation of the dust absorption factor, which correlates with the observed GALEX FUV-NUV colour indices. The total photometric extinction and dust-absorption corrected H\alpha\ fluxes were finally used to derive the star formation rates.Comment: 18 pages, 6 figures, 10 tables; accepted by MNRA

    Quest of shape coexistence in Zr isotopes

    Get PDF
    Background: The mass region with A approximate to 100 and Z approximate to 40 is known to experience a sudden onset of deformation. The presence of the subshell closure Z = 40 makes it feasible to create particle-hole excitations at a moderate excitation energy and, therefore, likely intruder states could be present in the low-lying spectrum. In other words, shape coexistence is expected to be a key ingredient to understand this mass region. Purpose: The aim of this work is to describe excitation energies, transition rates, radii, and two-neutron separation energies for the even-even Zr94-110 nuclei and, moreover, to obtain information about wave functions and deformation. Method: The interacting boson model with configuration mixing will be the framework to study the even-even Zr nuclei, considering only two types of configurations: 0particle-0hole and 2particle-2hole excitations. On one hand, the parameters appearing in the Hamiltonian and in the E2 transition operator are fixed trough a least-squares fit to the whole available experimental information. On the other hand, once the parameters have been fixed, the calculations allow to obtain a complete set of observables for the whole even-even Zr chain of isotopes. Results: Spectra, transition rates, radii, rho(2)(E0), and two-neutron separation energies have been calculated and a good agreement with the experimental information has been obtained. Moreover, a detailed study of the wave function has been conducted and mean-field energy surfaces and deformation have been computed too. Conclusions: The importance of shape coexistence has been shown to correctly describe the A approximate to 100 mass area for even-even Zr nuclei. This work confirmed the rather spherical nature of the ground state of Zr94-98 and its deformed nature for Zr100-110 isotopes. The sudden onset of deformation in Zr-100 is owing to the rapid lowering of a deformed (intruder) configuration which is high-lying in lighter isotopes

    Checklist of marine Crustacea Decapoda (excluded Brachyura) from Iberian Peninsula

    Get PDF
    An actualized and annotated checklist of marine Crustacea Decapoda (excluded Brachyura) from Iberian Peninsula and by sectors (Northern Spain (Gulf of Biscay to Galicia) - West Portugal - Gulf of Cádiz (S Portugal- SW Spain: Cape San Vicente to Gibraltar Strait) - Alborán Sea - Eastern Mediterranean Spain (Baleares-Levante)) is provided. Systematic changes and synonymies, new records, introduced species by anthropogenic activities and characterization of the spatial distribution of species are commented. In total 292 decapods species (not including Brachyura), belonging to 134 genera and 42 families, are cited along Iberian waters. Of these, 114 were not found by Zariquiey Álvarez (1968). The richest families are Paguridae, Hippolytidae and Palemonidae (with 28, 21 and 17 species respectively). By sectors, the Gulf of Cadiz shows the highest richness (178 species), consequence of the confluence of Atlantic and Mediterranean waters and of a greater depth range in this area (when comparing with the adjacent Alborán Sea sector). The total marine decapod species along Iberian waters (including crabs, Marco-Herrera et al., 2015) is, at least, 431. Also, other 13 freshwaters species have been cited in Iberian Peninsula.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Análisis de la relación entre la estrategia de diversificación y el desempeño de la empresa: el rol del ciclo económico

    Get PDF
    [EN] The relationship between corporate strategies and firm performance has been one of the key debates in the discipline of Strategic Management. There are studies that analyse the moderating role that certain variables may play in that relationship. These variables tend to refer to aspects within the firm or, at the very least, within the competitive environment in which a firm operates. Nevertheless, the empirical evidence on the part the general environment plays from an economic perspective is much less common, and focuses on large corporations and on periods of economic growth. Accordingly, using a panel of 1,828 Spanish manufacturing firms of different sizes, an analysis is conducted of the differences in Return On Assets (ROA), Growth in Sales (GS) and Labor Productivity (LP) between specialised firms, those with related diversification, and those with unrelated diversification, between 2002 and 2011, in which there was a period of growth alternated with another one of economic recession. Although some superiority is noted of related diversification and specialisation over unrelated diversification, the differences between strategies are less significant in periods of economic recession, and vary according to the dimension of performance considered. These results reveal the need to consider the economic cycle as a contingent factor that affects the impact corporate strategies have on firm performance.[ES] La relación entre las estrategias corporativas y el desempeño empresarial ha sido uno de los debates centrales en la disciplina de la dirección estratégica. Diversos estudios analizan el rol moderador que juegan diversas variables en esta relación. Dichas variables tienden a referirse a aspectos internos de la empresa o, si acaso, a aspectos del entorno competitivo en el que la empresa opera. Sin embargo, es más escasa la evidencia empírica sobre el rol que desempeña el entorno general y suele enfocarse en grandes empresas y en períodos de crecimiento económico. En consecuencia, utilizando un panel de 1.828 empresas manufactureras españolas de diferentes tamaños, se realiza un análisis de las diferencias de rentabilidad sobre activos, crecimiento de ventas y productividad laboral entre empresas especializadas, con diversificación relacionada y con diversificación no relacionada, entre los años 2002 y 2011, en los cuales hubo un período de crecimiento alternado con otro de recesión económica. Aunque se destaca cierta superioridad de la diversificación relacionada y la especialización sobre la diversificación no relacionada, las diferencias entre estrategias son menos significativas en los períodos de recesión económica y varían de acuerdo a la dimensión de desempeño considerada. Estos resultados revelan la necesidad de considerar el ciclo económico como un factor contingente que afecta el impacto que las estrategias corporativas tienen sobre el desempeño de la empresa.This paper has been supported by Project ECO2015-67434-R of Spanish Ministry of Economy and Competitiveness (Spain) and for the Excellent Research Group “Strategor” of URJC-Bank of Santander

    A cross-country quarterly database of real house prices: a methodological note

    Get PDF
    We build from (mainly) publicly available national sources a database of (nominal and real) house prices—complemented with data on private disposable income (PDI)—for 19 advanced countries at a quarterly frequency, starting in the first quarter of 1975. We select a house price index for each country that is consistent with the U.S. FHFA quarterly nationwide house price index for existing single-family houses (formerly called OFHEO house price index), and extend the country series back to 1975 with available historical data whenever necessary. Each house price index is seasonallyadjusted over the entire sample period and then rebased to 2005 = 100.> ; The house price indexes are expressed in nominal terms, and also in real terms using the personal consumption expenditure (PCE) deflator of the corresponding country. PDIs are always quoted in per capita terms using working age population of the corresponding country and can be similarly expressed in real terms with the PCE deflator. We aggregate all 19 countries in our database, weighted by their purchasing power parity-adjusted GDP shares in 2005, to compute an average (nominal and real) house price series and an average (nominal and real) per capita PDI series.Macroeconomics - Econometric models ; Income ; Gross domestic product

    A historical look at the labor market during recessions

    Get PDF
    Turmoil in housing, credit and financial markets plunged the U.S. economy into a recession that has taken a heavy toll on the labor market. The weakness that began during the second half of 2007 gravely worsened during a period of extreme financial stress in 2008, and the labor market has yet to recover. To put the recession's labor-market impact into perspective, we compare the past two years to previous downturns, including the Great Depression. We also examine the data commonly used to assess labor market conditions. While unemployment rates and nonfarm payroll losses are widely reported, a firm grasp of what they measure is critical to understanding what they tell us about the current state of the labor market.Recessions ; Labor market ; Unemployment

    Increased real house price volatility signals break from Great Moderation

    Get PDF
    The shift toward more volatile real house price growth, unaccompanied by a shift in the volatility of real GDP growth, offers evidence that house price dynamics and real output growth may have diverged beginning around the 2001 recession.Gross domestic product
    corecore