1,721,160 research outputs found
The forests of Pinus pinasterAiton subsp.pinasterof the NW-Italian Tyrrhenian sector
No full textThe present work deals with natural and subnatural forests of Pinus pinaster Aiton subsp. pinaster of Liguria and Tuscany regions. After a short introduction on the taxonomy and biogeography of Pinus pinaster subsp. pinaster, three new associations are described: Erico scopariae-Pinetum pinastri, Erico arboreae-Pinetum pinastri and Buxo sempervirentis-Pinetum pinastri. These associations belong to the new alliance Genisto pilosae-Pinion pinastri (Quercetalia ilicis order, Quercetea ilicis class). It also describes the new shrub association Genisto pilosae-Buxetum sempervirentis, dynamically linked to the forest of pine called Buxo sempervirentis-Pinetum pinastri. Characteristic and differential species, ecology, distribution, dynamic and catenal relationships of the new Pinus pinaster subsp. pinaster associations and the new alliance are also described
La vegetazione a Juniperus thurifera L. sulle Alpi occidentali
No full textWe here present a phytosociological study of the Juniperus thurifera L. phytocoenoses, including the chamaephyte phytocoenoses that are dynamically linked to them, in the western Alps of Italy and France. This study was conducted with the aim of understanding in more detail the significance of the 9560 habitat "Endemic Mediterranean forests of Juniperus spp." in the Italian territory. The Juniperus thurifera vegetation in the two Italian study areas, of Moiola, in Stura Valley (at altitudes between 800 m and 1,000 m), and of Valdieri, in Gesso Valley (at altitudes between 950 m and 1,670 m), have been referred to the new association Juniperetum communis-thuriferae. The vegetation of the French study areas that has already been attributed to the association Juniperetum hemisphaerico-thuriferae, which is widely spread also along the Iberian peninsula, has been recognized as the new subassociation amelanchieretosum embergeri, which distinguishes the French formations of J. thurifera from those Iberian. Both of these juniper wood types are dynamically connected with Mediterraneo-montane chamaephyte formations that have been referred to the new association Hyperico coris-Lavanduletum angustifoliae, which is here seen as the new subassociation tipica lavanduletosum angustifoliae and the thymetosum vulgaris subass. nova of the mainly thermo-xerophilous aspects. At lower altitudes, in chain contact with woods of Quercus pubescens or of Ostrya carpinifolia, the J. thurifera formations are substituted by others of J. phoenicea ssp. phoenicea, attributed to the new association Cytiso sessilifoliae-Juniperetum phoeniceae, to which are also referred the formations indicated as low supraMediterranean (Barbero & Quezel, 1986) that are present in the French Alpes-de-Haute-Provence
The vegetal landscape of the Republic of San Marino
No full textHere we present a phytosociological study of the vegetal landscape of the territory of the Republic of San Marino, situated in the northern Apennines, where it covers 61 km2. The bioclimate belongs to the subMediterranean variant of the temperate macrobioclimate. The vegetal landscape is here examined in relation to the characteristics of the substratum upon which it develops. On the calcareous heights, positioned on a short ridge that culminates in the peaks of Monte Titano (750 m), the forest vegetation belongs to the association of Lamiastro-Ostryetum carpinifoliae on the coldest aspects, and to the association Stellario holosteae-Quercetum pubescentis on those that are warmer. We also present the substitution phytocoenoses that are in dynamic connection with the woods. In the rocky sector of the calcareous ridge, the vegetation follows the morphology and micromorphology of the substratum, forming vegetational mosaics that are particularly complex and present rare vegetal associations, among which there is the association Crepido titani-Brassicetum robertianae colonising limited vertical portions of the calcareous cliffs, and the association Teucrio flavi-Ephedretum majoris, which is found on the microterraces that alternate with the cliffs. On the calcareous-marl conglomerate substrata and the molasses of Monte Cerreto, in part occupied by a wood that is now degraded, which is thought to be potentially referable to the association Aceri obtusati-Quercetum cerris. There is a particular vegetation coverage of Erica arborea and Ulex europaeus ssp. europaeus (this last species finds the eastern limits of its area in the location of San Marino) that is referred to the new association Crataego monogynae-Ulicetum europaei of the Rhamno-Prunetea class. The greater part of the territory of this State is formed of clay hills that have been subjected to the phenomena of rapid erosion of the substratum that has led to the formation of badlands. The vegetation is differentiated into the pioneering vegetal communities already seen for the badlands of the nearby Marecchia Valley, with the associations: Hainardio cylindricae-Salsoletum sodae, Elytrigio athericae-Artemisietum cretaceae and Arundinetum plinianae. In the areas that are no longer cultivated, however, vegetation of the association Senecio erucifolii-nuletum viscosae has developed. The study of the description of the vegetal landscape of San Marino Republic is completed by the analysis of the fragmentary river formations and the nitrophilic and anthropogenic formations
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Iterative deconvolutions to compensate wavelet stretching on 4th order traveltime kinematic
Full text linkSource to receiver distances employed in seismic data acquisition have been steadily increasing and it is now common to work with data acquired with more than 10 km of offset. Sub-basalt exploration and seismic undershooting are just two applications where long-offset reflections are valuable. However, such reflections are often subjected to muting to avoid NMO stretch artifacts, thus causing a loss of valuable information. It is therefore of interest to find ways to avoid the distortions caused by the standard NMO correction and to retrieve these portions of the recorded wavefield for a better use in the processing. To this end we develop a non-stretch NMO correction based on a wavelet estimation and on a iterative procedure of partial NMO correction and deconvolution. To drive the corrections we make use of 4th order traveltime curves, that further extend the offset range of usable reflections. Then we estimate time and space variant wavelets, by means of SVD along the sought traveltimes, that become the desired output for the deconvolution trying to retrieve the original shapes of the partially stretched wavelets. We test our method on a synthetic gather presenting time and offset varying wavelets and noise. This example demonstrate that our new algorithm effectively limits the stretching associated with the NMO correction and enables the recovery of those portions of the stacked sections which are typically ruled out by the mute function in the standard NMO correction
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