A la recerca de l'occità: Tres dialectes del nord

Treball de recerca realitzat per un alumne d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit cientí­fic del Jovent l'any 2009. El tema d'aquest treball és la llengua occitana, alhora dividit en un estudi sociolingüístic (situació actual de l'occità) i en un de dialectològic (estudi fonètic i morfològic del nord-occità). Tot seguit d'una introducció en què es parla de la relació de l'autor del present estudi amb el món de l'occià al llarg de quatre anys, es presenta la situació de la llengua tenint sempre present el seu context: història, estats on és pròpia, situació d'aquesta en les diferents regions en què es parla, qüestió del nom, problemàtica de l'estandardització, etc.. Es tracta de la greu situació en què es troba als tres estats en què és parlada, tot intentant d'explicar-ne els motius. A més a més, es fa referència a les distintes tendències quant a la normativització: estandardització rígida o flexible a la mena de l'''euskara batua'' o basc unificat. D'altra banda, en consonància amb l'objectiu de la preservació i valoració de la riquesa dialectal de l'occità, es fa una presentació sobretot fonètica (tot i que també es fa un tastet de morfologia) dels tres dialectes nord-occitans (alvernès, llemosí i vivaroalpí), que són els menys coneguts i estudiats, la qual cosa ha permès de ratificar la unitat del nord-occità.

Analysis of Pleistocene paleodrainage evolution in the Po Basin (Italy) by multivariate statistical techniques

In order to obtain a high-resolution Pleistocene stratigraphy, eleven continuouslycored boreholes, 100 to 220m deep were drilled in the northern part of the PoPlain by Regione Lombardia in the last five years. Quantitative provenanceanalysis (QPA, Weltje and von Eynatten, 2004) of Pleistocene sands was carriedout by using multivariate statistical analysis (principal component analysis, PCA,and similarity analysis) on an integrated data set, including high-resolution bulkpetrography and heavy-mineral analyses on Pleistocene sands and of 250 majorand minor modern rivers draining the southern flank of the Alps from West toEast (Garzanti et al, 2004; 2006). Prior to the onset of major Alpine glaciations,metamorphic and quartzofeldspathic detritus from the Western and Central Alpswas carried from the axial belt to the Po basin longitudinally parallel to theSouthAlpine belt by a trunk river (Vezzoli and Garzanti, 2008). This scenariorapidly changed during the marine isotope stage 22 (0.87 Ma), with the onset ofthe first major Pleistocene glaciation in the Alps (Muttoni et al, 2003). PCA andsimilarity analysis from core samples show that the longitudinal trunk river at thistime was shifted southward by the rapid southward and westward progradation oftransverse alluvial river systems fed from the Central and Southern Alps.Sediments were transported southward by braided river systems as well as glacialsediments transported by Alpine valley glaciers invaded the alluvial plain.Kew words: Detrital modes; Modern sands; Provenance; Principal ComponentsAnalysis; Similarity, Canberra Distance; palaeodrainage

A Log-linear model of grain size influence on the geochemistry of sediments

Sediment composition is mainly controlled by the nature of the source rock(s), and chemical (weathering) and physical processes (mechanical crushing, abrasion, hydrodynamic sorting) during alteration and transport. Although the factors controlling these processes are conceptually well understood, detailed quantification of compositional changes induced by a single process are rare, as are examples where the effects of several processes can be distinguished. The present study was designed to characterize the role of mechanical crushing and sorting in the absence of chemical weathering. Twenty sediment samples were taken from Alpine glaciers that erode almost pure granitoid lithologies. For each sample, 11 grain-size fractions from granules to clay (ø grades &-1 to &9) were separated, and each fraction was analysed for its chemical composition.The presence of clear steps in the box-plots of all parts (in adequate ilr and clr scales) against ø is assumed to be explained by typical crystal size ranges for the relevant mineral phases. These scatter plots and the biplot suggest a splitting of the full grain size range into three groups: coarser than ø=4 (comparatively rich in SiO2, Na2O, K2O, Al2O3, and dominated by “felsic” minerals like quartz and feldspar), finer than ø=8 (comparatively rich in TiO2, MnO, MgO, Fe2O3, mostly related to “mafic” sheet silicates like biotite and chlorite), and intermediate grains sizes (4≤ø &8; comparatively rich in P2O5 and CaO, related to apatite, some feldspar).To further test the absence of chemical weathering, the observed compositions were regressed against three explanatory variables: a trend on grain size in ø scale, a step function for ø≥4, and another for ø≥8. The original hypothesis was that the trend could be identified with weathering effects, whereas each step function would highlight those minerals with biggest characteristic size at its lower end. Results suggest that this assumption is reasonable for the step function, but that besides weathering some other factors (different mechanical behavior of minerals) have also an important contribution to the trend.Key words: sediment, geochemistry, grain size, regression, step function

Interaccions arbre-arbust al límit superior del bosc i efectes de gradients bioclimàtics en la vegetació

Durant el periode d’elaboració d’aquesta tesi hem aprofundit en el coneixement dels factors que controlen les dinàmiques espacio-temporals del límit superior del bosc. Aquest ecotò se situa entre el límit superior del bosc i els prats alpins i és susceptible a canvis ambientals, fet que provoca que fluctuï altitudinalment i latitudinalment en funció d’aquests canvis. Els motius d’aquesta dinàmica s’ha estudiat sovint des d’un punt de vista climàtic, però mai fins ara s’havia estudiat des d’un punt de vista de les interaccions entre organismes. Per aquest fet hem estat evaluant l’efecte de les interaccions planta-planta en la regulació de la dinàmica supraforestal. L’estudi l’hem emmarcat en un context alpí (als Pirineus Catalans) i en un context subàrtic (Lapònia, Suècia), fet que ens ha permès fer un estudi comparatiu en dos ecotons contrastats però homòlegs ecològicament. Hem desenvolupat una sèrie d’experiments considerant diversos factors (augment de temperatura, quantitat de nutrients, presència d’arbust, posició en l’ecotò); en les dues zones d’estudi hem fet una plantació de plançons dels arbres formadors del límit del bosc en les diverses situacions derivades de la combinació d’aquests factors, i hem fet el seguiment fenològic dels plançons durant tres periodes de creixement. Els resultats dels experiments ens han permès veure que les interaccions entre organismes tenen una gran importància en la regulació de la dinàmica supraforestal, tant als Pirineus com a Lapònia. Les interaccions planta-planta i planta-herbívors determinen el reclutament de plançons i per tant l’estructuració de les comunitats supraforestals. Per altra banda, la posició en l’ecotò evidencia la presència d’un gradient bioclimàtic; les manipulacions ambientals de temperatura i nutrients originen una resposta generalment positiva en el desenvolupament dels plançons, indicant que canvis en aquestes variables pot suposar alteracions notables de l’estructura forestal del límit del bosc. Per altra banda en aquest projecte també hem aprofundit en temes relacionats amb l'efecte dels gradients altitudinals en la distribució de plantes vasculars als Pirineus Catalans.

Interaccions arbre-arbust al límit superior del bosc i efectes de gradients bioclimàtics en la vegetació

Durant el periode d’elaboració d’aquesta tesi hem aprofundit en el coneixement dels factors que controlen les dinàmiques espacio-temporals del límit superior del bosc. Aquest ecotò se situa entre el límit superior del bosc i els prats alpins i és susceptible a canvis ambientals, fet que provoca que fluctuï altitudinalment i latitudinalment en funció d’aquests canvis. Els motius d’aquesta dinàmica s’ha estudiat sovint des d’un punt de vista climàtic, però mai fins ara s’havia estudiat des d’un punt de vista de les interaccions entre organismes. Per aquest fet hem estat evaluant l’efecte de les interaccions planta-planta en la regulació de la dinàmica supraforestal. L’estudi l’hem emmarcat en un context alpí (als Pirineus Catalans) i en un context subàrtic (Lapònia, Suècia), fet que ens ha permès fer un estudi comparatiu en dos ecotons contrastats però homòlegs ecològicament. Hem desenvolupat una sèrie d’experiments considerant diversos factors (augment de temperatura, quantitat de nutrients, presència d’arbust, posició en l’ecotò); en les dues zones d’estudi hem fet una plantació de plançons dels arbres formadors del límit del bosc en les diverses situacions derivades de la combinació d’aquests factors, i hem fet el seguiment fenològic dels plançons durant tres periodes de creixement. Els resultats dels experiments ens han permès veure que les interaccions entre organismes tenen una gran importància en la regulació de la dinàmica supraforestal, tant als Pirineus com a Lapònia. Les interaccions planta-planta i planta-herbívors determinen el reclutament de plançons i per tant l’estructuració de les comunitats supraforestals. Per altra banda, la posició en l’ecotò evidencia la presència d’un gradient bioclimàtic; les manipulacions ambientals de temperatura i nutrients originen una resposta generalment positiva en el desenvolupament dels plançons, indicant que canvis en aquestes variables pot suposar alteracions notables de l’estructura forestal del límit del bosc. Per altra banda en aquest projecte també hem aprofundit en temes relacionats amb l'efecte dels gradients altitudinals en la distribució de plantes vasculars als Pirineus Catalans.

La zonación estructural del hercínico del Pirineo Central en el anticlinorio de la Pallaresa

The Pyrenees are an alpine chain with hercynian basement rocks that outcrop in a large area called the Axial Zone. These rocks have been involved in the alpine deformation events although their main structural features resulted from the Hercynian orogeny. A relevant characteristic of the Hercynian basement is a change in structural style in depth which has been commonly studied and interpreted in the Pallaresa Anticlinorium, in the Central Pyrenees. This anticlinorium is a complex hercynian structural unit whose southern part belongs to the suprastructure whereas the northern part corresponds mostly to a transition zone between the infrastructure and the suprastructure. Rocks of the suprastructure show a steeply dipping slaty cleavage as the dominant structure, which is overprinting folds and thrusts rarely going with pervasive deformation. The transition zone results from a slaty cleavage, very often close to the bedding, overprinted by one or two steep crenulation cleavages. A gradual boundary exists between both structural levels and it can be observed that the deformation developing slaty cleavage in the suprastructure grades to a crenulation foliation in the transition zone. The gradual character of that boundary, as seen in the northern end of the transition zone, suggests that the southern sharp boundary is not original. That boundary is interpreted as a northward dipping inverse fault, possibly with Alpine age. That fault causes a relative uplift of the rocks of the transition zone and gives this sharp boundary with the suprastructural levels. It provokes the asymmetry in the Pallaresa anticlinorium

Seismic detection and characterization of landslides and other mass movements

Seismic methods used in the study of snow avalanches may be employed to detect and characterize landslides and other mass movements, using standard spectrogram/sonogram analysis. For snow avalanches, the spectrogram for a station that is approached by a sliding mass exhibits a triangular time/frequency signature due to an increase over time in the higher-frequency constituents. Recognition of this characteristic footprint in a spectrogram suggests a useful metric for identifying other mass-movement events such as landslides. The 1 June 2005 slide at Laguna Beach, California is examined using data obtained from the Caltech/USGS Regional Seismic Network. This event exhibits the same general spectrogram features observed in studies of Alpine snow avalanches. We propose that these features are due to the systematic relative increase in high-frequency energy transmitted to a seismometer in the path of a mass slide owing to a reduction of distance from the source signal. This phenomenon is related to the path of the waves whose high frequencies are less attenuated as they traverse shorter source-receiver paths. Entrainment of material in the course of the slide may also contribute to the triangular time/frequency signature as a consequence of the increase in the energy involved in the process; in this case the contribution would be a source effect. By applying this commonly observed characteristic to routine monitoring algorithms, along with custom adjustments for local site effects, we seek to contribute to the improvement in automatic detection and monitoring methods of landslides and other mass movements.

La vegetació de la serra de Moixeró i el massís de la Tosa d'Alp (Pirineus orientals).

This work offers an approach to the vegetation of the Pyrenean area mentioned above according to three successive and related levels -vascularflora, plant communities and plant landscape. The study area stretches over 147.5 square km (projected surface), nearly 70% belonging to Cadí-Moixeró Natural Park. Altitudes rise from 720 m a.s.l. (Southern part) and 1100 m a.s.l. (Northern part) to 2536 m a.s.l. at the top ofla Tosa d'Alp. Limestone, the most common substrate, constitutes the highest mountain ranges in the area and also the roughest relief. Slate, carbonated slate, marl, sandstone and different kinds of conglomerate are also present. The bioclimate of lower parts is axeromeric sub-mediterranean type in the Gaussen scale, with a marked continental factor in the Northern sector (Cerdanya district). High parts have high mountain climates -cold axeric, subalpine and alpine types.

First genome size estimations for some eudicot families and genera

First genome size estimations for some eudicot families and genera.- Genome size diversity in angiosperms varies roughly 2400-fold, although approximately 45% of angiosperm families lack a single genome size estimation, and therefore, this range could be enlarged. To contribute completing family and genera representation, DNA C-Values are here provided for 19 species from 16 eudicot families, including first values for 6 families, 14 genera and 17 species. The sample of species studied is very diverse, including herbs, weeds, vines, shrubs and trees. Data are discussed regarding previous genome size estimates of closely related species or genera, if any, their chromosome number, growth form or invasive behaviour. The present research contributes approximately 1.5% new values for previously unreported angiosperm families, being the current coverage around 55% of angiosperm families, according to the Plant DNA C-Values Database.

Molecular dating of caprines using ancient DNA sequences of Myotragus balearicus, an extinct endemic Balearic mammal

Background: Myotragus balearicus was an endemic bovid from the Balearic Islands (Western Mediterranean) that became extinct around 6,000-4,000 years ago. The Myotragus evolutionary lineage became isolated in the islands most probably at the end of the Messinian crisis, when the desiccation of the Mediterranean ended, in a geological date established at 5.35 Mya. Thus, the sequences of Myotragus could be very valuable for calibrating the mammalian mitochondrial DNA clock and, in particular, the tree of the Caprinae subfamily, to which Myotragus belongs. Results: We have retrieved the complete mitochondrial cytochrome b gene (1,143 base pairs), plus fragments of the mitochondrial 12S gene and the nuclear 28S rDNA multi-copy gene from a well preserved Myotragus subfossil bone. The best resolved phylogenetic trees, obtained with the cytochrome b gene, placed Myotragus in a position basal to the Ovis group. Using the calibration provided by the isolation of Balearic Islands, we calculated that the initial radiation of caprines can be dated at 6.2 ± 0.4 Mya. In addition, alpine and southern chamois, considered until recently the same species, split around 1.6 ± 0.3 Mya, indicating that the two chamois species have been separated much longer than previously thought. Conclusion: Since there are almost no extant endemic mammals in Mediterranean islands, the sequence of the extinct Balearic endemic Myotragus has been crucial for allowing us to use the Messinian crisis calibration point for dating the caprines phylogenetic tree.

Consideraciones generales sobre la flora del valle de Ribes

Coup d'oeil sur la flore de la vallée de Ribes (Pyrénées catalanes). On fait des commentaires critiques des principales publications apportant des données floristiques sur la contrée: le «Catàlech de la Flora de la Valí de Nuria», d'E. VAYREDA I VILA , la «Flora de la Valí de Nuria i els seus encontorns», de Frère SfeiMNEN, la «Flora de Catalunya», de J. CADEVALL I DARS et la «Végétation alpine des Pyrénées orientales», de J. BRAUNBLANQUET. On donne una liste partielle des espèces l'existence desquelles dans la région malgré y avoir été indiqués par divers auteurs parait inadmissible ou, au moins, fort douteuse. On indique la répartition dans la contrée de quelques plantes appartenant à des éléments phytogéographiques différents et on divise la contrée en des petits territoires, caractérisé chacun d'eux par de divers groupes d'espèces.

Plant diversity across five vegetation belts in the Pyrenees (Catalonia, Spain)

In this paper we analyze the size and habitat partitioning of the vascular floras of five areas of the NE Iberian Peninsula, representing five distinct vegetation belts and three floristic regions: Mediterranean (basal belt), medio-European (submontane and montane belts) and Boreo-Alpine (subalpine and alpine belts). Each area covered over 1000 ha, and was fairly uniform in terms of potential vegetation, bedrock and bioclimate. They excluded large villages and field areas, the landscape being mainly natural or moderately anthropized.

Disentangling the formation of contrasting tree line physiognomies combining model selection and Bayesian parameterization for simulation models.

Alpine tree-line ecotones are characterized by marked changes at small spatial scales that may result in a variety of physiognomies. A set of alternative individual-based models was tested with data from four contrasting Pinus uncinata ecotones in the central Spanish Pyrenees to reveal the minimal subset of processes required for tree-line formation. A Bayesian approach combined with Markov chain Monte Carlo methods was employed to obtain the posterior distribution of model parameters, allowing the use of model selection procedures. The main features of real tree lines emerged only in models considering nonlinear responses in individual rates of growth or mortality with respect to the altitudinal gradient. Variation in tree-line physiognomy reflected mainly changes in the relative importance of these nonlinear responses, while other processes, such as dispersal limitation and facilitation, played a secondary role. Different nonlinear responses also determined the presence or absence of krummholz, in agreement with recent findings highlighting a different response of diffuse and abrupt or krummholz tree lines to climate change. The method presented here can be widely applied in individual-based simulation models and will turn model selection and evaluation in this type of models into a more transparent, effective, and efficient exercise.

Prospecciones liquenologicas en el alto Aragon occidental

This work includes the first results of some excursions to a number of representative localities of Spanish Pyrenees in the region of Jaca, mainly focused on the epiphytes of the fir and beech woods, of Scots pine and of Pinus uncinata, calcareous and siliceous alpine rocks, and also on urban tree lichens in Jaca. The result is an annotated list comprising 228 species, of which 47 are new to Spain and a hundred were not previously reported from the Spanish Pyrenees. Furthermore, it has been possible to recognize some typical examples of alpine associations and also of epiphytic associations rich in oceanic lichens, well known outside of Spain.

Sedimentology and Stratigraphy of the Pleistocene sediments in Lake Llauset (Southern Pyrenees, Spain)-a first approach

The high alpine valleys in the Southem Pyrenees are characterised by a many small lakes and ponds. They occur above 2000 m and are said to have been formed by glacial erosion. The sediments in these basins should, therefore, contain s t p tigraphic information since deglaciation, at least. An interesting and may be one of the most important of these basins is Lake Llauset in the Alta Ribagorca. The Llauset basin has recently been developped for hydsopower production. In conection with the construction of the retaining wall at the 'Riegel' the sedimentary filling of the lake basin could be investigated, and the first sedimentological and stratigraphicalresults are presented.