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671.
Jesús Vías José Rolland María Luisa Gómez Carmen Ocaña Ana Luque 《Journal of Geographical Systems》2018,20(3):275-294
This paper describes a system for recommending hiking routes to help manage hiking activities in a protected area. The system proposes various routes, based on five criteria that maximize some aspects of hikers’ requirements (by analyzing the viability and difficulty of the trails) and also those of protected areas managers (by proposals to relieve congestion in areas already used for hiking and to promote awareness of new ones, as a contribution to environmental education). The recommendation system uses network analysis, multi-criteria decision analysis and geographic information system by free software tools: PgRouting, PostgreSQL and PostGIS. This system has been tested in Sierra de las Nieves Nature Reserve (Andalusia, Spain). Of the 182 routes obtained by the system, 62 (34%) are considered viable for hikers in Sierra de las Nieves, taking into account the type of user most likely to visit this protected area. Most routes have a high difficulty level, which is coherent with the mountainous character of the protected area. 相似文献
672.
673.
Azevedo Leonardo Narciso João Nunes Rúben Soares Amílcar 《Mathematical Geosciences》2021,53(5):1073-1093
Mathematical Geosciences - Three-dimensional subsurface elastic models inverted from seismic reflection data are the basis of the geo-modeling workflow. These models are often used to predict the... 相似文献
674.
Celia Ojeda-Martínez Francisca Giménez Casalduero Just T. Bayle-Sempere Carmen Barbera Cebrián Carlos Valle Jose Luis Sanchez-Lizaso Aitor Forcada Pablo Sanchez-Jerez Pablo Martín-Sosa Jesús M. Falcón Fuensanta Salas Mariagrazia Graziano Renato Chemello Ben Stobart Pedro Cartagena Angel Pérez-Ruzafa Fréderic Vandeperre Elisabeth Rochel Serge Planes Alberto Brito 《Ocean & Coastal Management》2009,52(2):89-101
A general conceptual framework for the management of marine protected areas (MPAs) was developed. The driver-pressure-state-impacts-response (DPSIR) framework was used to determine the elements affecting MPAs. The developed evaluation framework helped to select an appropriate suite of indicators to support an ecosystem approach, an assessment of the MPAs functioning and policy decisions. Gaps derived from the management and policy responses in the MPAs were also outlined. It was concluded that the DPSIR framework can help to simplify the complexity of MPA management. This document is a tool for policy makers, scientists and general public on the relevance of indicators to monitor changes and MPAs management. 相似文献
675.
Mercedes García-Antón Fátima Franco-Múgica Carlos Morla-Juaristi Javier Maldonado-Ruiz 《Quaternary Science Reviews》2011,30(5-6):757-768
The aim of this paper is to reconstruct the variation in the vegetation during the Holocene on the Northern Meseta through pollen analysis in order to determine the roles played by Pinus and Quercus in the vegetation dynamics. A new pollen sequence, Camporredondo, in the centre of the Duero River basin, Northern Meseta, Spain, is presented. It covers the period from ca 11,250 to 1630 cal yr BP. The Camporredondo sequence suggests that a forested landscape existed from the start of the Holocene with values of approximately 90% of arboreal pollen mainly derived from pine forests in the surroundings. Shortly after 8600 cal yr BP pine forests continued to dominate but the landscape became more open while stands of deciduous and evergreen Quercus developed. Around 4500 years ago, coinciding with the start of a period of less rainfall, the lacustrine areas in these territories began to silt up, favouring hydrophytic taxa such as Salix or Cyperaceae. A comparison with other Holocene pollen sequences from the central-eastern part of the Northern Meseta confirms the presence of pine forests in the whole region since the early Holocene. We discuss the variations of the general vegetation pattern in terms of the local or regional conditions at each site. Throughout the Holocene, Pinus forests dominated at least in the eastern half of the Duero River basin. The typical Holocene substitution of conifers by broadleaf species as recorded in other parts of the Iberian Peninsula and Europe, never takes place in the study area. The results of the present study suggest that the current view of the potential vegetation in the Spanish Northern Meseta should be reviewed. 相似文献
676.
677.
Zoltán Makó Ferenc Szenkovits Júlia Salamon Robert Oláh-Gál 《Celestial Mechanics and Dynamical Astronomy》2010,108(4):357-370
This paper provides a study of the stable and unstable regions around the smaller primary in the framework of the spatial
elliptic restricted three-body problem. The definitions and methods used to determine stable and unstable regions are extended
to three dimensions. New results concerning the stable and unstable regions around Mercury are obtained in the Sun–Mercury
system. 相似文献
678.
679.
Michael A. Dopita Daniela Calzetti Jesús Maíz Apellániz William P. Blair Knox S. Long Max Mutchler Bradley C. Whitmore Howard E. Bond John MacKenty Bruce Balick Marcella Carollo Michael Disney Jay A. Frogel Robert O’Connell Donald Hall Jon A. Holtzman Randy A. Kimble Patrick McCarthy Francesco Paresce Abhijit Saha Alistair R. Walker Joe Silk Marco Sirianni John Trauger Rogier Windhorst Erick Young 《Astrophysics and Space Science》2010,330(1):123-131
We present narrow band, continuum subtracted Hα, [S ii], Hβ, [O iii] and [O ii] data taken with the Wide Field Camera 3 on the Hubble Space Telescope in the nearby dwarf starburst galaxy NGC 4214. From these images, we identify seventeen new planetary nebula candidates, and seven supernova remnant candidates. We use the observed emission line luminosity function of the planetary nebulae to establish a new velocity-independent distance to NGC 4214. We conclude that the PNLF technique gives a reddening independent distance to NGC 4214 of 3.19±0.36 Mpc, and that our current best-estimate of the distance to this galaxy ids 2.98±0.13 Mpc. 相似文献
680.
Sophie Arnaud-Haond Núria Marbà Elena Diaz-Almela Ester A. Serrão Carlos M. Duarte 《Estuaries and Coasts》2010,33(4):878-889
The diversity–stability relationship is the subject of a long-standing debate in ecology, but the genetic component of diversity
has seldom been explored. In this study, we analyzed the interplay between genetic diversity and demographic responses to
environmental pressures. This analysis included 30 meadows formed by the Mediterranean endemic seagrass, Posidonia oceanica, showing a wide range of population dynamics ranging from a near equilibrium state to steep decline due to strong environmental
pressures close to aquaculture installations. Our results show that sedimentation rates are much better predictors of mortality
than clonal or genetic components. An unexpected positive trend was observed between genotypic diversity and mortality, along
with a negative relationship between allelic richness and net population growth. Yet such trends disappeared when excluding
the most extreme cases of disturbance and mortality, suggesting the occurrence of a threshold below which no relationship
exists. These results contrast with the positive relationship between genotypic diversity and resistance or resilience observed
in previous manipulative experiments on seagrass. We discuss the reasons for this discrepancy, including the difficulties
in designing experiments reflecting the complexity of natural meadows. 相似文献