Differentiation of human umbilical vein endothelial cells (HUVECS) into tubular structures resembling immature capillaries

Angiogenesis is the mechanism of new vessel formation from preexisting ones. It is a process of major relevance in tissue development and, more prominently, in pathological conditions. Kindler Syndrome, a rare disease affecting protein kindlin1, disrupts the dermo-epidermal junction resulting in skin blistering.! ! In order to interrogate the angiogenic effect of the Kindler Syndrome, bovine aortic endothelial cells and human umbilical vein endothelial cells were cultured in fibrin gel and MatrigelTM basement matrix. Qualitative analysis of the former indicated an enhanced angiogenic activity at basement membrane level induced by the Kindler genotype in human keratinocytes. This result was confirmed a posteriori by quantitative analysis with the Angiogenesis Analyzer plugin of ImageJ.! ! The quantitative results point to an increased release of mitogenic substances by keratinocytes lining the epidermis. This has the effect of enhancing angiogenesis in the dermal layer of the skin and is evidenced by the increased number of branches and branch length found under Kindler conditions, indicative of sprouting angiogenesis. Increased mesh area and number, along with a reduced mean mesh size found under Kindler conditions are indicative of an enhanced intussuspective angiogenic activity. The analysis of these five key parameters strongly suggest the proangiogenic influence of the Kindler genotype, expressed in epidermal keratinocytes, which affects vessel formation in the dermal layer of the skin.Ingeniería Biomédic

Towards efficient and reliable neural networks

Deep neural networks have achieved remarkable results in various applications, but when deployed to autonomous agents in the real world several challenges arise. Computational resources are limited and navigating through the real world requires low latency. Moreover, for many safety-critical applications like autonomous driving, deployed models must be reliable. In this thesis, we tackle these challenges with four main contributions: The first contribution addresses the constraints in computational resources via pruning at initialization. Unlike traditional pruning methods that prune fully trained networks, reducing the number of parameters before training improves memory and computational efficiency both at training and inference time. The proposed pruning mechanism can find trainable sub-networks at much higher sparsity constraints. The second contribution focuses on the reliability concerns raised by the existence of adversarial examples. We analyse single-step adversarial training methods and propose a simple modification to the Fast Gradient Signed Method that allows us to train robust neural networks more efficiently. Shifting the focus to reliability under natural domain shifts, the third contribution conducts a comprehensive study evaluating a large number of models in semantic segmentation. We find that while recent models enjoy increased robustness to distribution shifts, uncertainty estimation does not follow suit. We then identify methods from the literature to improve model reliability out of domain. The fourth contribution focuses on model reliability in the presence of unknown objects. Leveraging recent advancements in text-conditioned image generation, we present a pipeline to automatically add objects into images realistically. We show the resulting images can be used to test and fine-tune anomaly segmentation methods as well as to extend existing datasets to learn new classes

Suffering for the Suffering of the Other: A Levinasian Approach to Immigration

Rather than trying to justify pain and suffering in terms of a general theory of necessity in which individual pain becomes intelligible and senseful only in the narrative of the whole, as in Leibniz’ Theodicy, Emmanuel Levinas asserts that suffering is “useless.” Against theodicy, Levinas defends the insurmountable futility and absurdity of pain, a paradigmatic example of which is found in the concentration camps. We must therefore choose, Levinas asserts, either theodicy or ethics. This approach makes the subject very significant, since it encourages activity and responsibility in the face of a possible passivity and indifference towards others. This approach makes the subject very significant, since it encourages activity and responsibility instead of passivity and indifference towards others. In trying to understand how to restore meaning to suffering, Levinas offers a typology of the sources of suffering: sins of commission, sins of omission, and suffering the other’s suffering because of love. In order to illustrate the ethical dynamics of suffering, we analyze the contemporary situation of immigration, rejecting the case for open borders as failing to offer a restitution for the suffering caused. Keywords: Levinas. Theodicy. Ethics. Suffering. Vulnerability. Immigration. DOI: 10.7176/JPCR/49-05 Publication date:June 30th 202

Characteristics and dynamics of crescentic bar events at Castelldefels beach

Crescentic sand bars have been studied intensively in the last decades, resulting in good knowledge of some of their characteristics, but the processes behind their formation and destruction are not yet clear. This study aims to increase our understanding of the dynamics of crescentic bars at an open, dissipative Mediterranean beach (Castelldefels, 20 km southwest of Barcelona). Their dynamics have been analysed using a 4.25-year dataset of video images. The crescentic bar events have been identified using visual analysis, including the formation and destruction moments. The results show that crescentic bars hardly occurred when the sandbar was located close to the beach, whilst they developed often when the sandbar was further offshore. Wave conditions during crescentic bar formation were low- to intermediate-energy waves with both oblique and shore-normal angles of incidence. Sandbar straightening was preferably observed for oblique waves (of both intermediate and high energy). The alongshore wavelength and cross- shore amplitude of the crescentic bars have been also quantified, giving some 245 m and 10 m on average, respectively.Peer ReviewedPostprint (published version

Towards Formal Interaction-Based Models of Grid Computing Infrastructures

Grid computing (GC) systems are large-scale virtual machines, built upon a massive pool of resources (processing time, storage, software) that often span multiple distributed domains. Concurrent users interact with the grid by adding new tasks; the grid is expected to assign resources to tasks in a fair, trustworthy way. These distinctive features of GC systems make their specification and verification a challenging issue. Although prior works have proposed formal approaches to the specification of GC systems, a precise account of the interaction model which underlies resource sharing has not been yet proposed. In this paper, we describe ongoing work aimed at filling in this gap. Our approach relies on (higher-order) process calculi: these core languages for concurrency offer a compositional framework in which GC systems can be precisely described and potentially reasoned about.Comment: In Proceedings DCM 2013, arXiv:1403.768

Morphological changes, beach inundation and overwash caused by an extreme storm on a low-lying embayed beach bounded by a dune system (NW Mediterranean)

The geomorphological evolution of a low-lying, micro-tidal sandy beach in the western Mediterranean, Pals beach, was characterized using airborne Light Detection and Ranging (LiDAR) data. Data were collected in prior to and six months after the impact of an extreme storm with a return period of approx. 50 years, with the aim of characterizing the beach's response to the storm. The use of repeated high-resolution topographic data to quantify beach geomorphic changes has allowed assessment of the accuracy of different proxies for estimating beach volume changes. Results revealed that changes in the shoreline position cannot accurately reproduce beach volume changes on low-lying beaches where overwash processes are significant. Observations also suggested that volume estimations from beach profiles do not accurately represent subaerial volume changes at large profile distances on beaches with significant alongshore geomorphological variability. Accordingly, the segmentation of the beach into regularly spaced bins is proposed to assess alongshore variations in the beach volume with the accuracy of the topographic data. The morphological evolution of Pals beach during the study period showed a net shoreline retreat (- 4 m) and a significant sediment gain on the subaerial beach (+ 7.5 m3/m). The net gain of sediment is mostly due to the impact of the extreme storm, driving significant overwash processes that transport sediment landwards, increasing volume on the backshore and dunes. The increase of volume on the foreshore and the presence of cuspate morphologies along the shoreline also evidence post-storm beach recovery. Observed morphological changes exhibit a high variability along the beach related to variations in beach morphology. Changes in the morphology and migration of megacusps result in a high variability in the shoreline position and foreshore volume changes. On the other hand, larger morphological changes on the backshore and larger inundation distances occur when the beach and the dunes are lower, favouring the dominance of overwash. The observed storm-induced morphological changes differ from predicted beach storm impacts because of spatial and temporal variations in the beach morphology, suggesting that detailed morphological parameters and indicators used for predicting beach vulnerability to storms should be regularly updated in order to represent the pre-storm beach conditions. Finally, observed morphological changes in Pals Bay evidenced a different behaviour between natural and urban areas, with better post-storm beach recovery on natural areas where the beach is not artificially narrowed.Peer ReviewedPostprint (author's final draft

Efecto de la labor de despunte, realizada con distintas longitudes de estilo en las mazorcas, sobre el rendimiento de maiz semillero (Zea mays)

37 p.Se evaluó el efecto de la labor de despunte realizada con distintas longitudes de estilos en las mazorcas, sobre el rendimiento de maíz semillero (Zea mays). El experimento se insertó dentro de un cultivo de producción comercial de semillas híbridas; se ocupó como semilla básica dos líneas puras de maíz proporcionadas por la empresa ANASAC. Se utilizaron cuatro longitudes de estilo más un tratamiento testigo sin despuntar: T1 sin estilos expuesto, T2 inicio de emergencia de los estilos, T3 estilos con 2,5 cm. de longitud, T4 estilos con 5 cm. de longitud, y T0 testigo sin despuntar. Se utilizó un diseño completamente al azar, utilizando cuatro repeticiones por tratamiento; cada unidad experimental estuvo compuesta por cinco plantas. Los tratamientos a los estilos se realizaron en la etapa de floración del semillero. Para determinar el momento para realizar el despunte en cada tratamiento, se midió con una regla la longitud de los estilos desde que estos estaban expuestos, tomando la medida desde el ápice del estilo hasta el punto de emergencia del estilo con respecto a las hojas envolventes. La cosecha se efectuó el 15 de marzo del 2006, con una humedad de 38 %. Después de la cosecha, se procedió a secar las mazorcas durante 80 horas con aire forzado a 35º C hasta alcanzar 12,5 % de humedad en los granos. Luego se desgranó manualmente cada mazorca y se realizaron las siguientes mediciones: número total de hileras por mazorca, número total de granos por mazorca, peso de los granos por mazorca. Los resultados obtenidos permiten concluir que no hubo diferencias estadísticas entre los tratamientos sobre el número de hileras por mazorca. Realizar el despunte con longitudes de 2,5 cm. de estilos redujo en forma significativa tanto el número de granos por mazorca como el peso total de los granos por mazorca, respecto a los demás tratamientos

Sediment transport and dispersal in the nearshore of “flash-flood” rivers

River sediment dispersal on the near-shore of “flash-flood” rivers is investigated using a coupled wave-current-sediment transport model. Besòs and Llobregat rivers (short and mountainous rivers in NW Mediterranean Sea, near to Barcelona City) are used as examples to study the sediment transport under “flash-flood” regime. The modeling system COWAST which includes the coupling between the water circulation model ROMS and the wave model SWAN, is applied to assess the sediment dispersal mechanisms and deposition in the coastal area off the two river mouths. Preferential depositional areas such as mud-belts were identified from the simulations. The sediment dispersal pattern obtained by the model agrees with observational measurments. Complementary numerical simulations revealed sorting of sediment grain size in the cross-shelf direction.Peer ReviewedPostprint (published version

Diabetes Disrupts the Response of Retinal Endothelial Cells to the Angiomodulator Lysophosphatidic Acid

The objectives of this study were to investigate how diabetes mellitus (DM) influences responsiveness of retinal neovessels to lysophosphatidic acid (LPA) and to elucidate the underlying mechanism. To this end, we used an ex vivo assay in which neovessels sprouted from retinal explants (isolated from either control or DM mice) when cultured between two layers of collagen and in the presence of vascular endothelial growth factor-A. While DM had no effect on the formation of neovessels, it prevented LPA-induced regression. High-glucose (HG) treatment of retinal explants mimicked the DM phenotype. Similarly, primary retinal endothelial cells (RECs), which were subjected to HG treatment, organized into tubes that were resistant to LPA. HG caused LPA resistance within RECs by elevating ROS, which activated Src-family kinases that stimulated the extracellular signal–related kinase (Erk) pathway, which antagonized LPA-mediated signaling events that were required for regression. This ROS/Src/Erk pathway mechanism appeared to be the same route by which DM induced LPA resistance of retinal neovessels. We conclude that DM/HG reprograms signaling pathways in RECs to induce a state of LPA resistance