3,881 research outputs found

    Moderating role of perceived behavioral control in the theory of planned behavior: A preregistered study

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    Investigators frequently rely on the theory of planned behavior (TPB) as a conceptual framework to explain and predict human behavior in a variety of behavioral domains. Much of this research has focused on predicting behavioral intentions from attitudes, subjective norms and perceived behavioral control, typically by examining the additive effects of these constructs. However, in the original formulation of the TPB, perceived behavioral control was postulated to moderate the influence of attitude and subjective norm on intention. This tenet of the TPB has been drawing increasing attention in recent years. In a preregistered program of research conducted in two European countries (Germany and UK) concerning two different behaviors (exercising and reducing energy consumption), we found empirical support for the postulated moderating effects. The results suggest that as scores on perceived behavioral control increase, the strength of the association between attitude and intention increases as well, whereas the strength of the association between subjective norm and intention decreases. Implications of these findings for theory and future research are discussed

    SPIDER X - Environmental effects in central and satellite early-type galaxies through the stellar fossil record

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    A detailed analysis of how environment affects the star formation history of early-type galaxies (ETGs) is undertaken via high signal to noise ratio stacked spectra obtained from a sample of 20,977 ETGs (morphologically selected) from the SDSS-based SPIDER survey. Two major parameters are considered for the study: the central velocity dispersion (sigma), which relates to local drivers of star formation, and the mass of the host halo, which relates to environment-related effects. In addition, we separate the sample between centrals (the most massive galaxy in a halo) and satellites. We derive trends of age, metallicity, and [alpha/Fe] enhancement, with sigma. We confirm that the major driver of stellar population properties in ETGs is velocity dispersion, with a second-order effect associated to the central/satellite nature of the galaxy. No environmental dependence is detected for satellite ETGs, except at low sigma - where satellites in groups or in the outskirts of clusters tend to be younger than those in the central regions of clusters. In contrast, the trends for centrals show a significant dependence on halo mass. Central ETGs in groups (i.e. with a halo mass >10^12.5 M_Sun) have younger ages, lower [alpha/Fe], and higher internal reddening, than "isolated" systems (i.e. centrals residing in low-mass, <10^12.5 M_Sun, halos). Our findings imply that central ETGs in groups formed their stellar component over longer time scales than "isolated" centrals, mainly because of gas-rich interactions with their companion galaxies.Comment: 22 pages, 19 figures, accepted for publication in MNRA

    Incendis periurbans i incendis rurals : els casos de l'àrea metropolitana de Barcelona i de la comarca del Bages

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    Els incendis forestals necessiten un tractament específic d'acord amb les característiques pròpies del territori i amb les interaccions socials que hi tenen lloc. L'article que es presenta pretén mostrar dos àmbits que, tot i la seva proximitat, tenen unes característiques ignitòries completament diferents: l'àrea metropolitana de Barcelona, completament urbanitzada, i la comarca del Bages, amb una estructura molt més rural. Aquestes diferències, observades a partir de la recopilació i l'anàlisi dels incendis ocorreguts en aquests dos àmbits durant el període 1987-1998, mostren una distribució diferent de les ignicions en zones urbanes, molt més concentrades, i en zones rurals, molt més disperses i, per tant, més difícils de detectar. Aquest fet justifica la major superfície cremada al Bages que a l'AMB durant el període d'estudi. És important, doncs, que les polítiques que s'hagin d'aplicar s'adeqüin a les situacions amb característiques específiques i diferenciades en cada cas.Los incendios forestales necesitan un tratamiento específico respondiendo a las características propias del territorio y a las interacciones sociales que tienen lugar en él. El artículo que se presenta pretende mostrar dos ámbitos que, a pesar de su proximidad, tienen unas características ignitorias completamente diferentes: el área metropolitana de Barcelona, completamente urbanizada, y la comarca del Bages, con una estructura mucho más rural. Estas diferencias, observadas a partir de la recopilación y el análisis de los incendios ocurridos en estos dos ámbitos durante el periodo 1987-1998, muestran una diferente distribución de las igniciones en zonas urbanas, mucho más concentradas, y en zonas rurales, mucho más dispersas y, por lo tanto, más difíciles de detectar. Este hecho justifica la mayor superficie quemada en el Bages que en el AMB durante el periodo de estudio. Es importante, pues, que las políticas que se tengan que aplicar, se adecuen a las situaciones con características específicas y diferenciadas en cada caso.Il faut traiter les incendies forestiers d'une manière spécifique, en tenant en compte les interactions sociales qui ont lieu sur le territoire et les caractéristiques du territoire lui-même. Cet article-ci cherche à montrer les milieux qui, malgré leur proximité, ont des caractéristiques d'ignition complètement différentes: d'une part, l'Aire Métropolitaine de Barcelone (AMB), toute urbanisé; de l'autre, la région du Bages, qui a une structure beaucoup plus rurale. À partir de l'analyse des incendies qui ont eu lieu dans ces deux milieux de 1987 à 1998, on a observé des différences qui montrent une distribution inégale des incendies au sein des zones urbaines, beaucoup plus concentrées, et des zones rurales, nettement plus dispersées, et, par conséquent, plus difficiles à détecter. Ce fait justifie que, pendant l'été, une plus grande superficie ait été brûlée dans le Bages que dans l'AMB. Ainsi, il est important que les politiques à appliquer s'adaptent aux situations de caractéristiques spécifiques et différenciées dans chaque cas.Forest fires require specific response depending on the physical features of the terrain and its social use. This paper shows two areas which, have completely different ignitor characteristics despite their spatial proximity. These are the Metropolitan Area of Barcelona, which is completely urban, and the county of Bages, much more rural. These differences have been observed from the collection and analysis of the data of the fires that took place in these two areas between 1987 and 1998. The data show a different distribution of fire outbreaks in more dense urban areas and in more spread out rural areas, where fires are more difficult to detect. This fact explains why a larger area was burnt in Bages during the lapse of time studied. It is important, thus, that the policies to be applied are customized with specific and differentiate characteristics for every case

    SPIDER - IV. Optical and NIR color gradients in Early-type galaxies: New Insights into Correlations with Galaxy Properties

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    We present an analysis of stellar population gradients in 4,546 Early-Type Galaxies with photometry in grizYHJKgrizYHJK along with optical spectroscopy. A new approach is described which utilizes color information to constrain age and metallicity gradients. Defining an effective color gradient, \nabla_{\star}, which incorporates all of the available color indices, we investigate how \nabla_{\star} varies with galaxy mass proxies, i.e. velocity dispersion, stellar (M_star) and dynamical (M_dyn) masses, as well as age, metallicity, and alpha/Fe. ETGs with M_dyn larger than 8.5 x 10^10, M_odot have increasing age gradients and decreasing metallicity gradients wrt mass, metallicity, and enhancement. We find that velocity dispersion and alpha/Fe are the main drivers of these correlations. ETGs with 2.5 x 10^10 M_odot =< M_dyn =< 8.5 x 10^10 M_odot, show no correlation of age, metallicity, and color gradients wrt mass, although color gradients still correlate with stellar population parameters, and these correlations are independent of each other. In both mass regimes, the striking anti-correlation between color gradient and alpha-enhancement is significant at \sim 4sigma, and results from the fact that metallicity gradient decreases with alpha/Fe. This anti-correlation may reflect the fact that star formation and metallicity enrichment are regulated by the interplay between the energy input from supernovae, and the temperature and pressure of the hot X-ray gas in ETGs. For all mass ranges, positive age gradients are associated with old galaxies (>5-7 Gyr). For galaxies younger than \sim 5 Gyr, mostly at low-mass, the age gradient tends to be anti-correlated with the Age parameter, with more positive gradients at younger ages.Comment: Accepted for Publication in the Astronomical Journa

    Anàlisi del comportament dels incendis : Claus per prevenir-los

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    Els incendis han devastat àmplies zones de Catalunya en els últims anys, amb greus conseqüències per al medi ambient i per a l'economia de les àrees afectades. Algunes dades per fer-nos una idea: l'any 2005 es van produir 892 incendis en tota la comunitat autònoma, i en el que portem d'any ja n'hi ha hagut 618, segons xifres del Departament de Medi Ambient de la Generalitat. L'estudi del seu comportament i l'anàlisi de les dades obtingudes resulten fonamentals per reduir-los. Això és el que ha fet un grup d'investigadors de la UAB.Los incendios han devastado amplias zonas de Cataluña en los últimosaños, con graves consecuencias para el medio ambiente y la economíade las áreas afectadas. Algunas cifras para hacernos una idea: el año2005 se produjeron 892 incendios en toda la comunidad autónoma y enlo que llevamos de año ya ha habido 618, según datos del Departamentde Medi Ambient de la Generalitat. El estudio de su comportamiento y elanálisis de los datos obtenidos resultan fundamentales para reducirlos.Y esto es lo que ha hecho un grupo de investigadores de la UAB
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