888 research outputs found
Long slit spectroscopy of a sample of isolated spirals with and without an AGN
We present the kinematical data obtained for a sample of active (Seyfert) and
non active isolated spiral galaxies, based on long slit spectra along several
position angles in the Halpha line region and, in some cases, in the Ca triplet
region as well. Gas velocity distributions are presented, together with a
simple circular rotation model that allows to determine the kinematical major
axes. Stellar velocity distributions are also shown. The main result is that
active and control galaxies seem to be equivalent in all kinematical aspects.
For both subsamples, the departure from pure circular rotation in some galaxies
can be explained by the presence of a bar and/or of a spiral arm. They also
present the same kind of peculiarities, in particular, S-shape structures are
quite common near the nuclear regions. They define very similar Tully-Fisher
relations. Emission line ratios are given for all the detected HII regions; the
analysis of the [NII]/Halpha metallicity indicator shows that active and
non-active galaxies have indistinguishable disk metallicities. These results
argue in favour of active and non-active isolated spiral galaxies having
essentially the same properties, in agreement with our previous results based
on the analysis of near infrared images. It appears now necessary to confirm
these results on a larger sample.Comment: 35 pages, 54 figures, Accepted for publication in Astronomy &
Astrophysics The full paper with its figures is available on the anonymous
account of ftp.iap.fr in /home/ftp/pub/from_users/durret/marquez.ps.gz (999
kb
An international empirical study of greenwashing and voluntary carbon disclosure
Voluntary corporate environmental disclosure has increased significantly in the last decade. However, the increase in environmental disclosure has also been accompanied by the social questioning of its veracity. Previous
studies have mainly focused on the determinant factors behind corporate decisions to disclose environmental
data, with only limited consideration of both carbon performance and the veracity of the information disclosed.
Based on an international sample of firms from 12 countries, this paper analyzes the impact of regulative
pressures related to climate change on the likelihood of companies engaging in greenwashing. The results show
that the number of regulations related to climate change negatively influences the propensity of firms to engage
in greenwashing. Furthermore, firms in countries with stringent climate-related regulations are less likely to
participate in greenwashing practices. This paper adds to the existing literature concerning greenwashing by
demonstrating that institutional theory can deliver further insights into the explanation of corporate greenwashing behavior. This is the first study to incorporate international climate-related regulations into the analysis
of corporate greenwashing. It also provides a new method for identifying greenwashing firms, based on their
carbon performance and disclosure.This study has been supported by the Universidad de Sevilla VI PPIT [IV.3, 2018]
Synthesis, structure and reactivity of Pd and Ir complexes based on new lutidine-derived NHC/phosphine mixed pincer ligands
Coordination studies of new lutidine-derived hybrid NHC/phosphine ligands (CNP) to Pd and Ir have been performed. Treatment of the square-planar [Pd(CNP)Cl](AgCl2) complex 2a with KHMDS produces the selective deprotonation at the CH2P arm of the pincer to yield the pyridine-dearomatised complex 3a. A series of cationic [Ir(CNP)(cod)]+ complexes 4 has been prepared by reaction of the imidazolium salts 1 with Ir(acac)(cod). These derivatives exhibit in the solid state, and in solution, a distorted trigonal bipyramidal structure in which the CNP ligands adopt an unusual C(axial)–N(equatorial)–P(equatorial) coordination mode. Reactions of complexes 4 with CO and H2 yield the carbonyl species 5a(Cl) and 6a(Cl), and the dihydrido derivatives 7, respectively. Furthermore, upon reaction of complex 4b(Br) with base, selective deprotonation at the methylene CH2P arms is observed. The, thus formed, deprotonated Ir complex 8b reacts with H2 in a ligand-assisted process leading to the trihydrido complex 9b, which can also be obtained by reaction of 7b(Cl) with H2 in the presence of KOtBu. Finally, the catalytic activity of Ir–CNP complexes in the hydrogenation of ketones has been briefly assessed.CTQ2013-45011-P, CTQ2016-80814-R and CTQ2014 -51912-RE
An example of how to explore the geometry from logo optics: generation of regular polygons
La Geometría diferencial de la Tortuga se presta muy convenientemente a la exploración del espacio desde un punto de vista distinto a la Geometría Euclídea. En el presente artículo se presenta un ejemplo de micromundo que puede servir para comprender ese punto de vista y el isomorfismo existente entre las dos Geometrías, a la vez que abre un potente camino de exploración para compartir con nuestros alumnos en el proceso de enseñanza-aprendizaje. Se parte del "teorema del viaje completo" y del "camino cerrado simple" para generar un micromundo de polígonos regulares, estudiar la circunferencia como caso límite y mostrar algunos ejemplos de aplicación, que ilustren la práctica en el micromundo diseñado.The Differential Geometry of the turtle is adapted to the exploration of space from a different point of view to that of Euclidea Geometry. In this article, we present an example of micromundo, which can be used to understand that point of view and the isomorphism between the two Geometries. At the same time it opens the right door to exploring how to share with our pupils in the teaching-learning process. We start from the "teorema del viaje completo" and the "camino cerrado simple" in order to generate a "micromundo" of regular polygons and study the circumference as a last resort and show some examples of how to apply these in designing "micromundo".peerReviewe
Evaluation of the Technicon Axon analyser
An evaluation of the Technicon Axon analyser was carried out following the guidelines of the ‘Sociedad Española de Química Clínica’ and the European Committee for Clinical Laboratory Standards
Depth of faulting and ancien theat flows in the Kuiper region of Mercury from lobate scarp topography
Mercurian lobate scarp sare interpreted to be the surface expressions of thrust faults formed by
planetary cooling and contraction, which deformed the crust downto the brittle–ductile transition
(BDT) dep that the time of faulting. In this work we have used a for ward modeling procedure in order to
analyze the relation be tweens carptopography and fault geometrie sand dep thsas sociated with a
group of prominent lobate scarps (Santa Maria Rupes and twoun named scarps) located inthe Kuiper
region of Mercury for which Earth-based radar altimetry is available. Also aback thrust associated with
one of the lobate scarps has been included in this study. We have obtained best fits for depthsof
faul ting between 30 and 39 km; the results are consistent with the previous results for o ther lobate
scarps on Mercury.
The so-derived fault depths have been used to calculate surface heat flows for the time of faulting,
taking into account crustal heat source sand a heterogeneous surface temperature due to the variable
in solation pattern. Deduced surface heat flow sare be tween 19 and 39m Wm-2 for the Kuiper region,
and between 22 and 43 mWm-2 for Discovery Rupes. Both BDT depth sand heat flows are consistent
with the predictions of thermal history models for the range of time relevant for scarp formation
Peer drinking and alcohol use: The role of risk perception, perceived vulnerability, and gender: a moderated moderation analyses
Objective: To examine the moderating role of alcohol-related risk perception and perceived vulnerability to alcohol consequences in the relationship between descriptive drinking norms and personal alcohol use, and to determine if this moderation was, in turn, moderated by gender Methods: 538 college students (78.0% women, mean age = 21.2) from three Spanish universities completed a paper-and-pencil questionnaire. Simple moderation and moderated moderation analyses were conducted Results: Risk perception and perceived vulnerability moderated the relationship between drinking norms and alcohol use. This relationship weakened as perceived vulnerability and risk perception increased. High levels of risk perception and perceived vulnerability nullified the effect of perceived peer drinking on drinking quantity among both men and women, but higher values were necessary to nullify these effects among men Conclusions: Risk perception and perceived vulnerability appear to be useful in identifying specific subgroups more vulnerable to the effects of drinking norms and might be effective strategies for weakening its impact on alcohol use, with such strategies being more beneficial for women than men. These variables could thus be incorporated into norm-based interventions as they may improve their effectiveness. Our findings highlight the importance of designing gender-specific interventions to reduce the potential negative impact of alcohol consumption.Fil: Vera, Belén del Valle. Universidad Nacional de Córdoba. Instituto de Investigaciones Psicológicas. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Psicológicas; Argentina. Universidad Nacional de Córdoba. Facultad de Psicología; ArgentinaFil: Carmona Márquez, José. Universidad de Huelva; EspañaFil: González Ponce, Bella M.. Universidad de Huelva; EspañaFil: Fernández Calderón, Fermín. Universidad de Huelva; Españ
Monitoring of the morphologic reconstruction of deposited ablation products in laser irradiation of silicon
Using electron microscopy, atomic force microscopy, X-ray microanalysis, and IR spectroscopy, it was established that, in the regime of continuous laser irradiation of silicon at P = 170 W in different gaseous atmospheres with an oxygen impurity, SiOx composite films with a complex morphology form. The main components of ablation products are clusters that form during flight of ablation products and as a result of separation of SiOx-clusters from the zone of the irradiation channel. The roughness and density of the films depend on the heating temperature of the target surface and the type of deposited clusters
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