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Search Results: 1 - 10 of 169134 matches for " E. Calvo "
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Current state and problems of noble hardwoods plants: the Regions’ point of view
Calvo E
Forest@ , 2011, DOI: 10.3832/efor0666-008
Abstract: This paper illustrates the current state of noble hardwoods plants established in Italy since early ’90s, with the aim of describing the extension, distribution and quality of wood production obtained. Based on both results of this investigation and advices issued by administrative Regions, several considerations are discussed aimed to identify new directions for research and extension activities, as well as to support appropriate managing practices, in the light of the absence of an integrated system among the noble hardwoods productions, the agricultural sector and the timber market.
Composition-induced structural transitions in mixed rare-gas clusters
F. Calvo,E. Yurtsever
Physics , 2004, DOI: 10.1103/PhysRevB.70.045423
Abstract: The low-energy structures of mixed Ar--Xe and Kr--Xe Lennard-Jones clusters are investigated using a newly developed parallel Monte Carlo minimization algorithm with specific exchange moves between particles or trajectories. Tests on the 13- and 19- atom clusters show a significant improvement over the conventional basin-hopping method, the average search length being reduced by more than one order of magnitude. The method is applied to the more difficult case of the 38-atom cluster, for which the homogeneous clusters have a truncated octahedral shape. It is found that alloys of dissimilar elements (Ar--Xe) favor polytetrahedral geometries over octahedra due to the reduced strain penalty. Conversely, octahedra are even more stable in Kr--Xe alloys than in Kr_38 or Xe_38, and they show a core-surface phase separation behavior. These trends are indeed also observed and further analysed on the 55-atom cluster. Finally, we correlate the relative stability of cubic structures in these clusters to the glassforming character of the bulk mixtures.
Changes of Species Richness in Heathland Communities over 15 Years following Disturbances
L. Calvo,R. Tárrega,E. Luis
International Journal of Forestry Research , 2012, DOI: 10.1155/2012/547120
Abstract: The aim of this study was to define the species richness patterns over a period of 15 years during the vegetation recovery process after disturbances (burning, cutting and ploughing) in heathlands. Three communities were selected: two dominated by Erica australis and one dominated by Calluna vulgaris. The alpha and gamma diversity patterns were site specific and influenced by the ecological traits of dominant shrub species. The shrubland dominated by Erica australis, typical resprouters with a fast regeneration, showed the highest values of alpha and gamma diversity during the first 7 years of regeneration. The heathland dominated by Calluna vulgaris, an obligate seeder, had a contrasting pattern of alpha and gamma diversity, as the highest values appeared from year 7 until year 14. Thus, the speed of regeneration of the dominant shrub species could be the main factor affecting structural parameters in these communities. Species richness patterns did not vary in relation to the different types of perturbation. Cutting and burning would be the most suitable forestry management strategies to conserve Erica australis heathlands, but burning is more appropriate in Calluna vulgaris ones because cutting modified this community. 1. Introduction Maintaining plant diversity is a central goal in the management of biodiversity throughout the world [1, 2]. In some ecosystems like Mediterranean ones, biodiversity is of particular interest. Factors driving plant diversity in all ecosystems are of both theoretical and practical concern [3]. In Mediterranean ecosystems the anthropogenic activities like cultivation, intensive grazing, cutting, firewood exploitation, and wildfires have allowed a remarkable biodiversity to be maintained [4–9]. Heathlands and shrublands currently occupy extensive areas of the Mediterranean region covering a total surface of 110854?km2 [10]. These heathland communities are considered one of the types of forestry system, and according to the second Spanish National Forest Inventory (2IFN) [11] they represent 24% of the total surface area in Spain. In the same way, and according to the third National Forest Inventory (3IFN) [12], in the NW of the Iberian Peninsula (Leōn province) the surface covered by heathlands represents 45% of the total forestry surface [13]. In some parts of the Mediterranean Basin, heathlands had been considered marginal lands as they have low productivity and economic value [14]. For this reason, they have often been replaced by forests through extensive afforestation programmes, especially in Spain [15] and Portugal
Aneurismas del sector distal de la arteria cerebral anterior (arteria pericallosa)
Martinez,F.; Spagnuolo,E.; Calvo,A.;
Neurocirugía , 2005, DOI: 10.4321/S1130-14732005000400004
Abstract: the clinical, angiographic and surgical features of 13 (out of 18) patients harboring pericallosal aneurysms and operated on by the same group of neurosurgeons, are analyzed. the mortality rate of the whole series was 5.5% with good (gos ii) or excellent (gos i) recovery in the 91.7% of cases. according to the experience of the authors pericallosal aneurysms should not be considered to have a worse prognosis than aneurysms in other locations of the anterior circulation.
Amperometric enzyme electrodes
Calvo, E.J.;Danilowicz, C.;
Journal of the Brazilian Chemical Society , 1997, DOI: 10.1590/S0103-50531997000600002
Abstract: recent advances on amperometric enzyme electrodes are reviewed with particular emphasis on biosensors based on glucose oxidase and horseradish peroxidase. redox mediation by artificial soluble and polymer attached redox mediators is discussed in terms of recent theoretical developments and experimental verification. the dependence of the amperometric response on substrate and mediator concentration, enzyme concentration, electrode potential and film thickness are analyzed. possible applications in multienzyme schemes are also analyzed.
The effect of human factors (cutting, burning and uprooting) on experimental heatland plots
Calvo, L.,Tárrega, R,Luis, E.
Pirineos : Revista de Ecología de Monta?a , 1992,
Abstract: Regeneration response after prescribed burning, cutting and uprooting in experimental heatland plots dominated by Erica autralis subsp. aragonensis, was studied. The highest percentage cover of annual species was observed two years after the treatment. From that moment the therophytes tended to decrease and were replaced by perennial species natural to the community. The temporal heterogeneity calculated shows the greatest changes in the initial stages. Regeneration was by an autosuccession process, slower in the case of the uprooted plots due to the greatest impact. [fr] On étudie la réponse de la régénération après br lage, coupe et l'arrachage dans les parcelles expérimentales de bruyère avec dominance de E. australis subsp. aragonensis. On observe un plus grand pourcentage de couverture d'espèces annuelles après deux ans de traitements. à partir de ce moment, les therophytes diminuent, et sont remplacées par des espèces pérennes, propres de la communauté. Grace au calcul de l'hétérogénéité temporelle, on met en évidence les changements les plus importants lors des les premières étapes. La régénération se produit par un processus d'autosuccession, avec une récupération plus lente, car l'arrachage a été très drastique. [es] Se estudia la respuesta de regeneración tras quema, corta y arranque en parcelas experimentales de brezal, con dominio de E. australis subsp. aragonensis (L). Se observa el mayor porcentaje de cobertura de especies anuales a los dos a os de los tratamientos. A partir de ese momento, las terófitas tienden a disminuir, siendo sustituidas por especies perennes, propias de la comunidad. Mediante el cálculo de la heterogeneidad temporal se ponen de manifiesto los mayores cambios en las etapas iniciales. La regeneración se produce por un proceso de autosucesión, siendo el arranque más drástico por tanto muestra de una recuperación más lenta.
Respuesta al artículo "Curso IPR: método de identificación del paciente en riesgo" Reply to the article "IPR course: Method for the identification of patients at risk"
E. Calvo Herranz,F. Gordo Vidal
Medicina Intensiva , 2012,
Images in Intensive Medicine
F. Gordo Vidal,E. Calvo Herranz
Medicina Intensiva , 2007,
Falsa imagen de neumotórax en radiografía simple False image of pneumothorax in simple X-ray
F. Gordo-Vidal,E. Calvo Herranz
Medicina Intensiva , 2008,
Aneurismas del sector distal de la arteria cerebral anterior (arteria pericallosa) Aneurysms of the distal anterior cerebral artery
F. Martinez,E. Spagnuolo,A. Calvo
Neurocirugía , 2005,
Abstract: Se analizan las características clínicas, angiográficas y quirúrgicas de 13 pacientes portadores de aneurismas de la arteria pericallosa, operados por un mismo grupo de cirujanos, dentro de un total de 18 casos. Hubo una mortalidad del 5.5% (tomando en cuenta los 18 pacientes operados), con resultados buenos (GOS II) o excelentes (GOS I) en el 91.7%. Según la experiencia de los autores y de otros de referencia, los aneurismas de la arteria pericallosa no deberían considerarse de peor pronóstico que aquellas otras topografías dentro del sector anterior del polígono de Willis. The clinical, angiographic and surgical features of 13 (out of 18) patients harboring pericallosal aneurysms and operated on by the same group of neurosurgeons, are analyzed. The mortality rate of the whole series was 5.5% with good (GOS II) or excellent (GOS I) recovery in the 91.7% of cases. According to the experience of the authors pericallosal aneurysms should not be considered to have a worse prognosis than aneurysms in other locations of the anterior circulation.
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