1,503 research outputs found
Dinámica hidro-geomorfológica de la laguna del Charco del Toro (Complejo Palustre del Manto Eólico Litoral de El Abalario-Doñana). Parque Nacional de Doñana. Huelva
Quasars Clustering at z approx 3 on Scales less sim 10 h^{-1} Mpc
We test the hypothesis whether high redshift QSOs would preferentially appear
in small groups or pairs, and if they are associated with massive, young
clusters. We carried out a photometric search for \Ly emitters on scales
Mpc, in the fields of a sample of 47 known
QSOs. Wide and narrow band filter color-magnitude diagrams were generated for
each of the fields. A total of 13 non resolved objects with a
significant color excess were detected as QSO candidates at a redshift similar
to that of the target. All the candidates are significantly fainter than the
reference QSOs, with only 2 of them within 2 magnitudes of the central object.
Follow-up spectroscopic observations have shown that 5, i.e., about 40% of the
candidates, are QSOs at the same redshift of the target; 4 are QSOs at
different z (two of them probably being a lensed pair at z = 1.47); 2
candidates are unresolved HII galaxies at z0.3; one unclassified and one
candidate turned out to be a CCD flaw. These data indicate that at least 10% of
the QSOs at z3 do have companions.
We have also detected a number of resolved, rather bright \Ly Emitter
Candidates. Most probably a large fraction of them might be bright galaxies
with [OII] emission, at z 0.3. The fainter population of our
candidates corresponds to the current expectations. Thus, there are no strong
indication for the existence of an overdensity of \Ly galaxies brighter than m
25 around QSOs at 3.Comment: 29 pages, 8 figures, tar gzip LaTex file, accepted to appear in Ap
Integrability of Lie systems and some of its applications in physics
The geometric theory of Lie systems will be used to establish integrability
conditions for several systems of differential equations, in particular Riccati
equations and Ermakov systems. Many different integrability criteria in the
literature will be analyzed from this new perspective and some applications in
physics will be given.Comment: 16 page
Lie bialgebra contractions and quantum deformations of quasi-orthogonal algebras
Lie bialgebra contractions are introduced and classified. A non-degenerate
coboundary bialgebra structure is implemented into all pseudo-orthogonal
algebras starting from the one corresponding to . It allows
to introduce a set of Lie bialgebra contractions which leads to Lie bialgebras
of quasi-orthogonal algebras. This construction is explicitly given for the
cases . All Lie bialgebra contractions studied in this paper define
Hopf algebra contractions for the Drinfel'd-Jimbo deformations .
They are explicitly used to generate new non-semisimple quantum algebras as it
is the case for the Euclidean, Poincar\'e and Galilean algebras.Comment: 26 pages LATE
The Socio-Environmental Survey: a tool for an integrated study of protected areas. The case of Sierra Sur de Sevilla and Sierra de Cádiz
La declaración de Espacios Naturales Protegidos ha producido con frecuencia conflictos con las poblaciones locales en la gestión de la conservación de la naturaleza. En respuesta a esta realidad han surgido nuevos métodos y estrategias que buscan una mejor integración de la componente social en las áreas protegidas. Este artículo presenta los resultados de una Encuesta Socio-Ambiental (ESA) realizada durante la elaboración de una propuesta de Espacio Natural Protegido para la Red de Espacios Naturales Protegidos de Andalucía en la campiña agrícola del Subbético, entre las provincias de Sevilla y Cádiz (sur de España). A partir de los datos obtenidos se propone y discute la aplicación de la figura de Paisaje Protegido (tipo Categoría V de UICN) asociada a un modelo de gestión participativa abierta.The declaration of Protected Areas has frequently led to conflicts with local populations because of nature conservation management. In response to this reality new methods and strategies are emerging that are looking for a better integration of the social component in Protected Areas. This article shows the results of a Socio-Environmental Survey (SES) conducted during the elaboration of a Protected Area proposal for the Andalusian Protected Areas Network in the Subbetic agricultural “campiña”, between Seville and Cádiz provinces (Southern Spain). Based on the data obtained, the application of the Protected Landscape figure (type Category V of IUCN) associated to an open participatory management model is proposed and discussed
Recommended from our members
Deconstructing self-organisation in microentrepreneurship: a social embeddedness perspective
Research overemphasises the facilitative role of institutions in cluster formation. It overlooks the collective actions by microentrepreneurs when confronting issues of microentrepreneurship in a weak institutional environment. Drawing from a social embeddedness perspective in entrepreneurship, we analyse the mechanisms underlying their methods of self-organisation for collective action, particularly in cluster formation. Interviews involving 19 microentrepreneurs in rural China revealed that they self-organised to form self-serving clusters by engaging in small-scale entrepreneurial acts of reciprocal and cooperative behaviours, solidarity, camaraderie, and by adopting Chinese business ideologies. Such an understanding contributes to research on clusters, as it reveals ways in which microentrepreneurs in a weak institutional environment leverage localised economic, social, and cultural forces to collectively form self-serving clusters. This foregrounds the role of microentrepreneurs in establishing a socioeconomic equilibrium in such an environment and it holds social, academic, and policy implications
- …