Hobsbawm, testigo apasionado de la Era de los extremos

Hobsbawm, historiador especializado en el siglo XIX, sólo tardíamente ha abordado de manera amplia la historia del siglo XX, especialmente en su obra Age of Extremes. The Short Twentieth Century 1914-1991. En ella, así como a su autobiografía (Interesting Times) y otros trabajos, analiza el devenir de este siglo, no a la manera de un historiador desapasionado, sino como "observador participante". En este artículo se repasan las interpretaciones de Hobsbawm y las críticas que han despertado, especialmente sus tesis sobre la centralidad, en la dinámica del siglo, de la revolución soviética de 1917 y sus consecuencias; o el enfrentamiento entre la coalición de fuerzas herederas de la Ilustración y las corrientes irracionalistas anti-ilustradas. También se recogen las polémicas sobre su supuesto eurocentrismo o el carácter -marxista o no- de las categorías analíticas que utiliza. En todo caso, su espléndido fresco histórico plagado de intuiciones brillantes está atravesado por una preocupación política (el fracaso del "sueño de Octubre") sin la cual no puede entenderse, y que desemboca en un diagnóstico negativo del presente y una evidente perplejidad ante el futuro.Hobsbawm, historiador especialitzat en el segle XIX, només tardanament ha abordat de manera àmplia la història del segle XX, especialment en la seva obra Age of Extremes. The Short Twentieth Century 1914-1991. En ella, així com a la seva autobiografia (Interesting Times) i altres treballs, analitza l'esdevenir d'aquest segle no a la manera d'un historiador desapassionat sinó com a "observador participant". En aquest article es repassen les interpretacions de Hobsbawm i les crítiques que han despertat, especialment les seves tesis sobre la centralitat, en la dinàmica del segle, de la revolució soviètica de 1917 i les seves conseqüències; o l'enfrontament entre la coalició de forces hereves de la Il·lustració i els corrents irracionalistes anti-il·lustrades. També es recullen les polèmiques sobre el seu suposat eurocentrisme o el caràcter -marxista o no- de les categories analítiques que utilitza. En tot cas, el seu esplèndid fresc històric plagat d'intuïcions brillants està travessat per una preocupació política (el fracàs del "somni d'Octubre") sense la qual no pot entendre's, i que desemboca en un diagnòstic negatiu del present i una evident perplexitat davant el futur. Hobsbawm, a historian specialised in the 19th century, dealt with the 20th Century late in his career, specially in his work Age of Extremes. 520 3_ $a The Short Twentieth Century 1914-1991. In it, as well as in his autobiography (Interesting Times) and other works, he analyses the development of that century not as a dispassionate historian, but as an "active observer". In this paper we will look into Hobsbawm's interpretations and the critiques they have given rise to, in particular his theses about the paramount importance of the Russian Revolution of 1917 and of its consequences for the dynamics of the century; or the clash between the coalition of forces that were heir to the Enlightenment and the Counter-Enlightenment irrationalist currents. The paper also focuses on the polemics about his supposed Eurocentrism or the nature of the analytical categories he uses, whether they are Marxist or not. In any case, his splendid historical fresco, full of brilliant intuitions, is influenced by a political concern (the failure of the dream of Red October) without which it cannot be understood, and it ends up with a negative diagnosis of the present and an evident perplexity about the future

Experimental characterisation of rate-dependent compression behaviour of fibre reinforced composites

Fibre reinforced polymers (FRP) materials are being increasingly used for aerospace and automotive structural applications. One of the critical loading conditions for such applications is impact, consequently, understanding of the composite behavior under such loads becomes critical for structural design. The analysis and design process for achieving impact-resistant composite structures requires rate-dependent constitutive models, which, in turn, requires material properties of the composite over a range of strain rates. It is, therefore, the objective of the research to investigate the strain rate-dependent behavior of fiber reinforced composites under compressive loads for a wide range of fiber orientations. Quasi-static (≈ 1e-3 s-1) and high loading (≈ 200 s-1) rates are considered for the experimental study. Accordingly, two different test setups are utilized, a screw-driven universal testing machine for quasi-static tests and a Split Hopkinson Pressure Bar (SHPB) system for dynamic tests. The stress-strain response of the composite is reported for the different fiber orientations and the strain rates, revealing the rate-dependent characteristics of the carbon fiber reinforced composite. From the test results, it is observed that, the dependency of the fracture strength on the loading rate is significant. The results are summarised in terms of the failure envelope in the transverse compression-in-plane shear σ22-σ12 plane for the two strain rates

An integrated inverse numerical–experimental approach to determine the dynamic Mode-I interlaminar fracture toughness of fibre composites

A combined numerical–experimental methodology is presented to determine the dynamic Mode-I fracture properties of Fibre-Reinforced Polymer (FRP) composites. The experimental aspect consists of a modified Wedge-Double cantilever Beam (WDCB) test using a Split Hopkinson Pressure Bar (SHPB) set-up followed by a numerical inverse modelling strategy using cohesive-zone approach. The proposed method is inherently robust due to the use of three independent comparison metrics namely, the strain–displacement response, the crack length history and the crack opening history to uniquely determine the delamination properties. More importantly, the complexity of dealing with the frictional effects between the wedge and the DCB specimen is effectively circumvented by utilising appropriate acquisition techniques. The proposed methodology is applied to extract the high-rate interlaminar fracture properties of a carbon fibre reinforced composite, IM7/8552 and it is further shown that a high level of confidence in the calibrated data can be established by adopting the proposed methodology

A Wedge-DCB Test Methodology to Characterise High Rate Mode-I Interlaminar Fracture Properties of Fibre Composites

A combined numerical-experimental methodology is presented to measure dynamic Mode-I fracture properties of fiber reinforced composites. A modified wedge-DCB test using a Split-Hopkinson Bar technique along with cohesive zone modelling is utilised for this purpose. Three different comparison metrics, namely, strain-displacement response, crack propagation history and crack opening history are employed in order to extract unique values for the cohesive fracture properties of the delaminating interface. More importantly, the complexity of dealing with the frictional effects between the wedge and the DCB specimen is effectively circumvented by utilising right acquisition techniques combined with an inverse numerical modelling procedure. The proposed methodology is applied to extract the high rate interlaminar fracture properties of carbon fiber reinforced epoxy composites and it is further shown that a high level of confidence in the calibrated data can be established by adopting the proposed methodology

Un final para un nuevo comienzo

Treball Final de Màster Universitari en Psicologia del Treball, de les Organitzacions i en Recursos Humans. Codi: SBE513. Curs acadèmic: 2015-2016Hace ya varios años, en la universidad, mientras estudiaba la carrera de psicología, descubrí que era en el ámbito laboral donde quería y donde creía que los conocimientos y habilidades, que durante aquellos cinco años la licenciatura me había aportado, podían no solo ser útiles, sino que era aquel, un camino que podía satisfacerme profesionalmente y en el que podía marcar la diferencia. Desde entonces muchas cosas han pasado, no siempre fáciles, tanto personal como profesionalmente, pero esa idea original siempre ha sido mi meta. Hace ya algo más de un año, la oportunidad de alcanzarla vino de la mano de este Máster, y hoy al final del mismo, la conclusión no puede ser más satisfactoria. No solo ha supuesto un avance a nivel de formación, sino que me ha aproximado a nuevas visiones y perspectivas. Este trabajo de fin de Máster tiene por objetivo principal, poner de manifiesto cuales son las competencias que a lo largo de este año he ido adquiriendo. El reto no ha sido fácil, pero veo el final de esta andadura como un nuevo comienzo en mi futuro profesional.Makes already several years, in the University, while studying the career of psychology, discovered that was in the field labor where wanted to and where believed that them knowledge and skills, that during those five years the degree me had contributed, could not only be useful, but was that, a road that could meet me professionally and in which could mark the difference. Since then many things have last, not always easy, both personal as professional, but that idea original always has been my goal. Ago already something more than one year, the opportunity of reach it came of the hand of this Master, and today at the end of the same, the conclusion not can be more satisfactory. Not only has alleged a progress at the level of training, but I has approximate to new visions and perspectives. This Master's work has as it’s main objective, to show which are the skills that I have gained this year. The challenge has not been easy, but I see the end of this journey as a new start in my career

On the Rate-dependent Plasticity Modelling of Unidirectional Fibre-reinforced Polymeric Matrix Composites

Three different approaches to plasticity are investigated to model the experimentally-observed non-linear behaviour of unidirectional fibre-reinforced polymeric matrix materials. The first and simplest approach consists on assuming independent one-dimensional rate-dependent plasticity on in-plane (12) and through-thickness longitudinal (13) shear components of the Cauchy stress tensor. The second, employs a 3D extension of the plane stress Hill'48 anisotropic plastic surface. The third and the last is formulated as a quadratic yield function inspired by Puck's fracture initiation criterion. It searches for a plastic localisation plane in which a certain combination of normal and shear stresses is maximum. Numerical simulations are conducted to analyse the off-axis compression behaviour of carbon fibre reinforced epoxy composite under varying loading rates. The afore-mentioned three different approaches are explored with an aim to predict the experimentally-observed non-linear response of such composites. The model parameters are determined using a deterministic inverse modelling strategy employing an iterative domain reduction optimisation technique. As far as the experiments are concerned, the quasi-static and medium rate tests were carried out in universal testing machines, while the experiments at high rate were conducted in a Split Hopkinson Pressure Bar system. The effectiveness in terms of accuracy and robustness of the three approaches are discussed

Differential chemosensitivity to antifolate drugs between RAS and BRAF melanoma cells.

BACKGROUND: The importance of the genetic background of cancer cells for the individual susceptibility to cancer treatments is increasingly apparent. In melanoma, the existence of a BRAF mutation is a main predictor for successful BRAF-targeted therapy. However, despite initial successes with these therapies, patients relapse within a year and have to move on to other therapies. Moreover, patients harbouring a wild type BRAF gene (including 25% with NRAS mutations) still require alternative treatment such as chemotherapy. Multiple genetic parameters have been associated with response to chemotherapy, but despite their high frequency in melanoma nothing is known about the impact of BRAF or NRAS mutations on the response to chemotherapeutic agents. METHODS: Using cell proliferation and DNA methylation assays, FACS analysis and quantitative-RT-PCR we have characterised the response of a panel of NRAS and BRAF mutant melanoma cell lines to various chemotherapy drugs, amongst them dacarbazine (DTIC) and temozolomide (TMZ) and DNA synthesis inhibitors. RESULTS: Although both, DTIC and TMZ act as alkylating agents through the same intermediate, NRAS and BRAF mutant cells responded differentially only to DTIC. Further analysis revealed that the growth-inhibitory effects mediated by DTIC were rather due to interference with nucleotide salvaging, and that NRAS mutant melanoma cells exhibit higher activity of the nucleotide synthesis enzymes IMPDH and TK1. Importantly, the enhanced ability of RAS mutant cells to use nucleotide salvaging resulted in resistance to DHFR inhibitors. CONCLUSION: In summary, our data suggest that the genetic background in melanoma cells influences the response to inhibitors blocking de novo DNA synthesis, and that defining the RAS mutation status could be used to stratify patients for the use of antifolate drugs