13,676 research outputs found

    Approach to climatophilous vegetation series of Serra da Estrela (Portugal)

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    This work contains the study results of climatophilous vegetation series from Serra da Estrela, the highest mountain on the Portuguese mainland. Located in central-northern Portugal in the Estrelensean Sector (Carpetan-Leonese Subprovince), the Serra da Estrela has several bioclimatic stages, mainly resulting from slope and altitude ranges: mesomediterranean, submediterranean mesotemperate, supramediterranean, submediterranean supratemperate, and submediterranean orotemperate. In each of these belts are observed changes in plant communities that determine variations in terms of the vegetation series. The methodology was based on Dynamic-Catenal Phytosociology. The results show the presence of five climatophilous series; their structural characteristics and dynamics are described in this paper: 1. Lycopodio clavati–Junipereto nani S.; 2. Saxifrago spathularis–Betuleto celtibericae S.; 3. Holco mollis–Querco pyrenaicae S.; 4. Arbuto–Querco pyrenaicae cytisetoso grandiflori S.; e 5. Viburno tini–Querco roboris S

    Effective Theories for 2+1 Dimensional Non-Abelian Topological Spin Liquids

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    In this work we propose an effective low-energy theory for a large class of 2+1 dimensional non-Abelian topological spin liquids whose edge states are conformal degrees of freedom with central charges corresponding to the coset structure su(2)k⊕su(2)k′/su(2)k+k′su(2)_k\oplus su(2)_{k'}/su(2)_{k+k'}. For particular values of k′k' it furnishes the series for unitary minimal and superconformal models. These gapped phases were recently suggested to be obtained from an array of one-dimensional coupled quantum wires. In doing so we provide an explicit relationship between two distinct approaches: quantum wires and Chern-Simons bulk theory. We firstly make a direct connection between the interacting quantum wires and the corresponding conformal field theory at the edges, which turns out to be given in terms of chiral gauged WZW models. Relying on the bulk-edge correspondence we are able to construct the underlying non-Abelian Chern-Simons effective field theory.Comment: 41 pages, 5 figures, typos corrected, references added, published versio

    Comparing the Productive Efficiency of Cooperatives and Private Enterprises: The Portuguese Wine Industry as a Case Study

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    This paper compares the efficiency of cooperatives and private enterprises in the Portuguese wine industry, employing data envelopment analysis (DEA). The use of DEA for the analysis of comparative efficiency within a sector is a key tool in evaluating organizational competitiveness. Competitiveness should be based on benchmarking the different types of organizations that comprise the viniculture sector. We conclude that Portuguese wine cooperatives, on average, are more efficient than their private counterparts. Economic implications arising from the study are discussed.cooperatives, private enterprises, technical efficiency, DEA, wine industry, Portugal, Agribusiness,

    New Proposals on Portuguese Vegetation (II)

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    As a consequence of the geobotanical studies that have been developed in west and southern areas of the Iberian Peninsula, four new phytosociological associations are proposed, integrated in the perennial mesophytic grasslands of Stipo giganteae-Agrostietea castellanae (Serratulo flavescentis-Celticetum giganteae, Armerio macrophyllae-Celticetum giganteae, Centaureo rothmaleranae-Celticetum giganteae, and Centaureo coutinhoi-Dactyletum lusitanici). For each proposed unit, besides its syntaxonomical fitting, we present its ecological diagnosis and the serial and catenal context, as well as its patrimonial value

    Suitable methods for landscape evaluation and valorization: the third dimension in landscape metrics

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    Landscape metrics have been widely developed over the last two decades. One of the major recent developments in landscape metrics analysis was the integration of the third dimension. Topography has an extremely important role in ecosystems function and structure, even though the common analysis in landscape ecology only considers a planimetric surface, which leads to some erroneous results particularly in mountain areas. In this study we tested landscape metrics behaviour in 13 sample areas of 10,000 m2 each in several topographical conditions of Central Alentejo, Portugal. The significance analysis of the results achieved in planimetric and three-dimensional environments is presented
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