789 resultados para Corominas, Josep Maria
Resumo:
Halecium petrosum and Halecium pusillum on the alga Halimeda tuna from Tossa de Mar, northeastern Spain, were studied. Asexual reproduction of H. petrosum, by stolonisation, occurred throughout the year except for July and August. Asexual reproduction of H. pusillum, by planktonic propagules, occurred throughout the year. Sexual reproduction was limited to the autumn in H. petrosum and spring in H. pusillum. The growth rates of colonies of both species were rapid but declined with increased size. Mean colony size over two consecutive two week periods increased approximately five-fold and three-fold for H. petrosum, and six-fold and four-fold for H. pusillum. Mortality was estimated to be high for both species, especially in summer. The maximum life span of colonies (ramets) of both species was estimated to be only eight weeks. Consequently most colonies do not reproduce sexually. The absence of reproduction of H. petrosum in summer, when the turnover of algal thalli was greatest, probably contributed to the summer decline in its abundance. In both species the genet (clone) survives for unknown, possibly very long, periods by asexual reproduction which facilites colonisation of other substrata.
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La gran cantidad de libros y papeles escritos alrededor de la guerra civil aspañola 1936-1939 han prestado relativamente poca atención al examen de la evolución económica de esapaña durante aquellos años y, más en particular, al desarrollo de la actividad económica y de los modos de producción industrial en Cataluña durante el mismo período, que, así pues, por un conjunto de circunstancias han quedado, en algunos aspectos, marginados de dichos estudios. [. . .]
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In recent years, contradictory reports about whether or not an unconformity exists at the base of the Upper Ordovician succession of the Pyrenees have been made. In the Cerdanya area (Central Pyrenees), good outcrop evidence for this unconformity is displayed at the base of the Rabassa conglomerates. In this area, the Upper Ordovician rocks overlie a tilted Cambro-Ordovician sequence, displaying an angular unconformity and indicating a break in the stratigraphic series. Moreover, the existence of such an unconformity is supported by the distribution of Variscan minor structures, suggesting that the Cambro-Ordovician and the Upper Ordovician strata initially had different orientations before the main Variscan folding.
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An example of the relationship that exist between the preferred crystaliografic orientation of quartz grains and the attitude of the mylonite foliation of quartz-feldspar mylonites is described. These rocks are the result of the inhomogeneous deformation under low-grade metamorphic conditions of a late Hercynian granodiorite, intruded into the gneisses of the slopes of the Canig massif (Eastern Pyrenees). The Costabona mylonites have a quartz c-axis fabric in pseudo-twogirdles symmetrical with respect to the mylonite foliation and perpendicular to the shearband systems which produce an extensional crenulation of the mylonite foliation.
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Els materials pre-hercinians i el granit de Costabona estan travessats per un conjunt de filons de quars de fins a 15 km de longitud, coneguts com a 'Esquerdes de Roja'. Aquests filons estan localment afectats per un sistema de bandes milonítiques i per un altre posterior de fractures. A partir de l'anilisi microtermometrica de les inclusions fluides primàries en quars, ha estat obtinguda una temperatura de formació de l'ordre de + 280 C per la major part del quars, i una temperatura de + 250 C per als monocristalls que omplen esquerdes i cavitats. Els filons s'haurien format a partir de solucions mineralitzants que contenien ~ a + C, a++, K+ i, en menor proporció, ~ g + + .fins una salinitat total de l'ordre del 20/@ en pes de la Na CI.
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The Upper Cretaceous volcanic succession of Hannah Point is the best exposure of the Antarctic Peninsula Volcanic Group on L ivingston Island. The aim of the present paper is to contribute to the characterisation of the stratigr a p hy and petrogr a p hy of this little studied succession, and briefly discuss some aspects of the eru p t ive style of its volcanism. The succession is about 470 m thick and is here subdivided into five lithostratigraphic units (A to E from base to top). Unit A, approximately 120 m thick, is mainly composed of polymict clast-supported volcaniclastic breccias and also includes a dacitic lava laye r. Interstratified in the breccias of this unit, there is a thin laminated devitrified layer which shows some degree of welding. Unit B, approx imately 70 m thick, is almost entirely composed of volcaniclastic breccias, and includes a volcaniclastic conglomerate laye r. Breccias in this unit can be subdivided into two distinct types; polymict clast-supported breccias, and monomict matrix-supported breccias rich in juvenile components and displaying incipient welding. Unit C, about 65 m thick, is mainly composed of basaltic lavas, which are interlayered with minor vo lcaniclastic breccias. Unit D, approximately 65 m thick, is lithologically similar to unit B, composed of an alternation of polymict clasts upported breccias and matrix-supported breccias, and includes a volcaniclastic conglomerate laye r. Unit E, about 150 m thick, is mainly formed of thick andesitic lava layers. Minor basaltic dykes and a few normal faults cut the succession, and the contact betwe e n units A and B can be interpreted both as an unconformity or a fault. The matrix-supported breccias included in the succession of Hannah Point have high contents of juvenile components and incipient welding, which suggest that part of the succession is the result of pyroclastic fragmentation and emplacement from pyroclastic flows. In contrast, the polymict clast-supported breccias suggest reworking of previous deposits and deposition from cool mass flows. The lavas indicate eff u s ive volcanic eruptions, and the absence of features indicative of subaqueous volcanism suggests that at least these portions of the succession were emplaced in a subaerial environment .
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En el presente trabajo se proponen cuatro cambios nomenclatures: Verbascum erosun Cav. (= V. laciniatum (Poiret) O. Kuntze); V. masguindali (Pau) comb, nov.; V. pseudocreticurn nom. nov. y V. fontqueri nom. nov. Se adjuntan dos nuevas ilustraciones, una clave dicotómica de las ocho especies ibéricas y baleáricas con cuatro estambres (Celsia L.) y una relación de los ejemplares de herbario estudiados. Verbascum masguindali se indica por primera vez en la Península Ibérica.
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Se aporta un catálogo florístico de 313 táxones seleccionados procedentes de algunas de las sierras septentrionales del Sistema Ibérico aragonés: Sierras de Villarroya, Vicort, Cucalón y Retuerta, Monte de Herrera, la Modorra de Bádenas y Baños de Segura. La visita a algunas de las localidades clásicas de ASSO, ha permitido confirmar numerosas citas de las que aparecen en su Synopsis stirpium indigenarum Aragoniae (1779), así como establecer algunas sinonimias. En el aspecto nomenclatural se propone una nueva combinación: Androsace elongata L. subsp. breistrofferi (Charpin & Greuter) J . Molero & JM. Montserrat, comb. nova. En el aspecto corológico, una lista, que no pretende ser exahustiva, sobre novedades para la Flora aragonesa y otras especies escasamente citadas que incluye: Paronychia rouyana, Suene scabriflora, Sisymbrium macroloma, Hutera hispida, Saxifraga losae var. camarae, Rosa arvensis, Aphanes cornucopioides, Lathyrus cirrhosus, Trifolium retusum, Trifolium gemellum, Seseli cantabricum, Daucus durieua, Anthemis alpestris fma. ligulata , Hieracium castellanum, Festuca capillifolia , Avenula pubescens, Carex tomentosa, etc.
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Se estudian los números cromosomáticos de 11 especies de plantas vasculares recolectadas en Marruecos. Entre ellas cuatro constituyen primeros recuentos.
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La guia consta d’un conjunt de documents en format pdf i d’una web (http://www.videoaccessible.udl.cat) que es complementen per donar pautes, recomanacions i exemples necessaris per poder mostrar informació en format vídeo digital accessible per a les persones amb diferents discapacitats
Resumo:
Aquest document dóna les pautes bàsiques per poder incorporar vídeos incrustats en una pàgina web codificada en HTML5, amb un reproductor accessible. Així mateix, es dóna una introducció a l’eina ccPlayer, reproductor de vídeos que està implementat com un objecte SWF Flash i que permet l’addició de subtítols. Veurem també una altra eina similar, el JWPlayer.
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Notas florísticas sobre plantas vasculares de los Ports de Beseit. Algunas son nuevas citas para esta zona: Ephedra nebrodensis, Equisetum palustre, Iberis saxatilis subsp. saxatihs; otras raras: Neotinea maculata, Ridolfia segetum, Ranunculus parviflorus. Arrbenatberum album es indicado por primera vez en Cataluña.
Resumo:
The alliance Agropyro-Rumicion in the eastern half of the IberianPyrenees. This alliance, related to eurosiberian landscapes, is represented in the studied area by three associations, all them inhabiting wet and ruderalized soils: Mentho-Juncetum (very frequent and chiefly formed by Juncus inflexus and Mentha longifolia), Festuco-Caricetum (more sporadic and grassland-shaped) and Rorippo-Agrostietum (only recorded from the upper part of the river Ter, dominated by the rare Rorippa sylvestris and more or less related to the alliance Bidention in some way).
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Descripció de l¿estructura, la composició florística i l'ecologia dels boscs mesòfils de les Muntanyes Catalanidiques septentrionals. És analitzada la Variabilitat d'aquest bosc a les diverses parts de la serralada. Són estudiats els sintàxons Doronico-Fraxinetum, representat per les subassociacions doronicetosum, melampyretosum, vincetosum, festucetosum, luzuletosum i aretosum.
Resumo:
The correlation between the species composition of pasture communities and soil properties in Plana de Vic has been studied using two multivariate methods, Correspondence Analysis (CA) for the vegetation data and Principal Component Analysis (PCA) for the soil data. To analyse the pastures, we took 144 vegetation relevés (comprising 201 species) that have been classified into 10 phytocoenological communities elsewhere. Most of these communities are almost entirely built up by perennials, ranging from xerophilous, clearly Mediterranean, to mesophilous, related to medium-European pastures, but a few occurring in shallow soils are dominated by therophytes. As for the soil properties, we analysed texture, pH, depth, bulk density, organic matter, C/N ratio and the carbonates content of 25 samples, correspondingto representative relevés of the communities studied.