Algunes recomanacions per a l'exposició oral del treball de final de grau

La realització del Treball Final de Grau pot comportar, en alguns casos, la possibilitat de defensa de la recerca davant un tribunal especialment nomenat per a aquest objectiu. Això vol dir que la valoració de l'estudi que ha donat lloc al document presentat es farà, no tant sols per la seva forma i pel seu contingut, sinó també tenint en compte la seva presentació oral i la capacitat de qui el defensa de respondre les qüestions que des del tribunal i hagin estat formulades. Modestament, vull oferir algunes pautes que poden ser útils a l'alumnat en aquest moment del Treball

Editorial

Presentació del volum 2/2 (2023)

Editorial

Presentació del volum 1/2 (2022).Presentación del volumen 1/2 (2022).Presentation of volume 1/2 (2022)

Evaluating the destabilization susceptibility of active rock glaciers in the French Alps

In this study, we propose a methodology to estimate the spatial distribution of destabilizing rock glaciers, with a focus on the French Alps. We mapped geomorphological features that can be typically found in cases of rock glacier destabilization (e.g. crevasses and scarps) using orthoimages taken from 2000 to 2013. A destabilization rating was assigned by taking into account the evolution of these mapped destabilization geomorphological features and by observing the surface deformation patterns of the rock glacier, also using the available orthoimages. This destabilization rating then served as input to model the occurrence of rock glacier destabilization in relation to terrain attributes and to spatially predict the susceptibility to destabilization at a regional scale. Significant evidence of destabilization could be observed in 46 rock glaciers, i.e. 10&thinsp;% of the total active rock glaciers in the region. Based on our susceptibility model of destabilization occurrence, it was found that this phenomenon is more likely to occur in elevations around the 0&thinsp;∘C isotherm (2700–2900&thinsp;m&thinsp;a.s.l.), on north-facing slopes, steep terrain (25 to 30∘) and flat to slightly convex topographies. Model performance was good (AUROC&thinsp;=&thinsp;0.76), and the susceptibility map also performed well at reproducing observable patterns of destabilization. About 3&thinsp;km2 of creeping permafrost, or 10&thinsp;% of the surface occupied by active rock glaciers, had a high susceptibility to destabilization. Considering we observed that only half of these areas of creep are currently showing destabilization evidence, we suspect there is a high potential for future rock glacier destabilization within the French Alps.</p

Morphological and molecular characterization of adults and larvae of Crassicauda spp. (Nematoda: Spirurida) from Mediterranean fin whales Balaenoptera physalus (Linnaeus, 1758)

Crassicauda boopis is known to infect the kidneys and vascular system of mysticetes included Balaenoptera physalus and has been recently reported in Mediterranean waters. Identification at the species level relies on the observation of morphological features of the adult parasites, but field conditions during necropsy and the massive reaction of the host's immune system often prevent optimal conservation of the extremities. Moreover, larval stages of Crassicauda have never been described and no sequences are available in public databases to help such identification. Adult and larvae of Crassicauda were isolated from four specimens of B. physalus and studied with morphological and molecular techniques. Specimens of C. anthonyi, C. grampicola and Crassicauda sp. isolated from Ziphius cavirostris, Grampus griseus, Stenella coeruleoalba and Tursiops truncatus respectively were studied as well. Sequences of nuclear markers 18S and ITS-2 and of mitochondrial gene cox1 were obtained and phylogenetic relationships within the genus Crassicauda were analysed. Analysis of the ITS2 grouped the dif- ferent species in accordance with morphological identification, as already evidenced in literature for other Spirurida. A higher intra-specific variability was observed for the cox1 gene, for which two species (C. grampicola and C. anthonyi) did not appear as monophyletic in the tree. Well-developed non-attached larval specimens in the intestinal lumen of a whale calf were molecularly identified as C. boopis, allowing new insights on the life cycle of this species. This work broadens the genetic database on cetaceans parasites, allowing species identi- fication even in challenging field conditions or in poor conservation of the samples; moreover, the first mor- phological description of C. boopis larvae is provided

Three decades of volume change of a small greenlandic glacier using ground penetrating radar, structure from motion, and aerial photogrammetry

Glaciers in the Arctic are losing mass at an increasing rate. Here we use surface topography derived from Structure from Motion (SfM) and ice volume from ground penetrating radar (GPR) to describe the 2014 state of Aqqutikitsoq glacier (2.85 km2) on Greenland's west coast. A photogrammetrically derived 1985 digital elevation model (DEM) was subtracted from a 2014 DEM obtained using land-based SfM to calculate geodetic glacier mass balance. Furthermore, a detailed 2014 ground penetrating radar survey was performed to assess ice volume. From 1985 to 2014, the glacier has lost 49.8 ± 9.4 106 m3 of ice, corresponding to roughly a quarter of its 1985 volume (148.6 ± 47.6 106 m3) and a thinning rate of 0.60 ± 0.11 m a-1. The computations are challenged by a relatively large fraction of the 1985 DEM (∼50% of the glacier surface) being deemed unreliable owing to low contrast (snow cover) in the 1985 aerial photography. To address this issue, surface elevation in low contrast areas was measured manually at point locations and interpolated using a universal kriging approach. We conclude that ground-based SfM is well suited to establish high-quality DEMs of smaller glaciers. Provided favorable topography, the approach constitutes a viable alternative where the use of drones is not possible. Our investigations constitute the first glacier on Greenland's west coast where ice volume was determined and volume change calculated. The glacier's thinning rate is comparable to, for example, the Swiss Alps and underlines that arctic glaciers are subject to fast changes