509 research outputs found

    Tuning Magnetic Avalanches in Mn12-ac

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    Using micron-sized Hall sensor arrays to obtain time-resolved measurements of the local magnetization, we report a systematic study in the molecular magnet Mn12_{12}-acetate of magnetic avalanches controllably triggered in different fixed external magnetic fields and for different values of the initial magnetization. The speeds of propagation of the spin-reversal fronts are in good overall agreement with the theory of magnetic deflagration of Garanin and Chudnovsky \cite{Garanin}.Comment: 8 pages, 7 figures; discussion expanded and revise

    Numerical study of VIV over a flexible riser

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    This study is based on the simulation of the fluid-structure interaction on risers. We aim to quantify the structural response of these long flexible pipes, used for the extraction of offshore petroleum when they are subjected to marine currents. Toe occurring phenomenon is known as VIV (Vortex induced VIbration). These problems are a relevant challenge for several offshore companies, which are associated with K-Epsilon in a Citeph project. Toe project's goal is to use the FSI simulation tool developed by K-Epsilon and initially used for the simulation offlexible membranes such as sails, to model these VIV phenomena. Toe problem of VIV in the case of a riser is a strongly coupled problem, meaning that the added mass is not negligible compared to the mass of the structure. This can be challenging for most fluid-structure interaction software. A strongly coupled algorithm is presented [6]. First, numerical results of fluid around cylinders are presented and compared to experimental results ([l], [10]) with several turbulence models, and time step sizes. Toen, Chaplin's benchmark is presented with experimental / numerical comparison [3]

    The fossil vertebrates from Somosaguas (Pozuelo, Madrid, Spain)

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    [ES] Dos yacimientos de vertebrados, situados en el Campus de Somosaguas de la Universidad Complutense (Pozuelo de Alarcón, Madrid), han proporcionado unos 600 restos identificables en estados de conservación muy variados, pertenecientes a unas veinte especies de tamaños muy diversos, desde mastodontes a musarañas. Su estudio permite fechar su edad en unos 14 m.a. y reconstruir un periodo árido en la cuenca de Madrid, ocupada durante el Mioceno medio por bosques y sabanas subtropicales con fuertes avenidas y sin ríos permanentes. En estos yacimientos se puede realizar una enseñanza práctica de la Paleontología de Vertebrados, para formación de estudiantes universitarios en el estudio y la gestión del Patrimonio Paleontológico.[EN] Two vertebrate fossil sites, situated in the Universidad Complutense Campus of Somosaguas, (Pozuelo de Alarcón, Madrid, Spain) have yielded about 600 identifiable rests in different preservation states, belonging to about twenty species of highly diverse sizes, from mastodons to shrews. Their study allows dating at about 14 m.y., and reconstructing an arid climate epoch in the Madrid basin during middle Miocene times, occupied by subtropical woodlands and savannahs with strong floods and without permanent rivers. These fossil sites allow practical teaching of Vertebrate Palaeontology, and preparing university students in the Palaeontological Heritage study and management.Hemos recibido financiación y personal respaldo del Rectorado de la Universidad Complutense de Madrid, de los Decanatos de la Facultad de Ciencias Políticas y Sociología y de la Facultad de Ciencias Geológicas, y del Departamento de Paleontología de esta Facultad. El Departamento de Paleobiología del Museo Nacional de Ciencias Naturales (CSIC) realiza su investigación en el marco del Convenio de Colaboración con la Comunidad de Madrid a través de la Dirección General de Patrimonio Histórico Artístico de la Consejería de Educación.Peer reviewe

    One year overview and follow-up in a post-COVID consultation of critically ill patients

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    The long-term clinical management and evolution of a cohort of critical COVID-19 survivors have not been described in detail. We report a prospective observational study of COVID-19 patients admitted to the ICU between March and August 2020. The follow-up in a post-COVID consultation comprised symptoms, pulmonary function tests, the 6-minute walking test (6MWT), and chest computed tomography (CT). Additionally, questionnaires to evaluate the prevalence of post-COVID-19 syndrome were administered at 1 year. A total of 181 patients were admitted to the ICU during the study period. They were middle-aged (median [IQR] of 61 [52;67]) and male (66.9%), with a median ICU stay of 9 (5–24.2) days. 20% died in the hospital, and 39 were not able to be included. A cohort of 105 patients initiated the follow-up. At 1 year, 32.2% persisted with respiratory alterations and needed to continue the follow-up. Ten percent still had moderate/severe lung diffusion (DLCO) involvement (<60%), and 53.7% had a fibrotic pattern on CT. Moreover, patients had a mean (SD) number of symptoms of 5.7 ± 4.6, and 61.3% met the criteria for post-COVID syndrome at 1 year. During the follow-up, 46 patients were discharged, and 16 were transferred to other consultations. Other conditions, such as emphysema (21.6%), COPD (8.2%), severe neurocognitive disorders (4.1%), and lung cancer (1%) were identified. A high use of health care resources is observed in the first year. In conclusion, one-third of critically ill COVID-19 patients need to continue follow-up beyond 1 year, due to abnormalities on DLCO, chest CT, or persistent symptoms.This study was supported in part by ISCIII (CIBERESUCICOVID, COV20/00110), co-funded by ERDF, “Una manera de hacer Europa,” donation program “Estar Preparados,” UNESPA, Madrid, Spain and Fundación Soria Melguizo (Madrid, Spain). DG-C had received financial support from Instituto de Salud Carlos III (Miguel Servet 2020: CP20/00041), co-funded by the European Social Fund (ESF)/“Investing in your future.” JB acknowledged receiving financial support from Instituto de Salud Carlos III (ISCIII; Miguel Servet 2019: CP19/00108), co-funded by the European Social Fund (ESF), “Investing in your future.”Peer ReviewedArticle signat per 29 autors/es: Jessica González (1,2,3,4), María Zuil (1,2,3,4), Iván D. Benítez (2,3,4), David de Gonzalo-Calvo (2,3,4), María Aguilar (1,2), Sally Santisteve (1,2,3,4), Rafaela Vaca (1,2), Olga Minguez (1,2), Faty Seck (1,2), Gerard Torres (1,2,3,4), Jordi de Batlle (2,3,4), Silvia Gómez (1,2,3,4), Silvia Barril (1,2,3,4), Anna Moncusí-Moix (2,3,4), Aida Monge (1,2,3,4), Clara Gort-Paniello (2,3,4), Ricard Ferrer (4,5), Adrián Ceccato (4), Laia Fernández (4,6), Ana Motos (4,6), Jordi Riera (4,5), Rosario Menéndez (4,7), Darío Garcia-Gasulla (8), Oscar Peñuelas (4,9), Gonzalo Labarca (10,11), Jesús Caballero (12), Carme Barberà (13), Antoni Torres (4,6) and Ferran Barbé (1,2,3,4) * on behalf of the CIBERESUCICOVID Project (COV20/00110, ISCIII) // (1) Department of Pulmonary, Hospital Universitari Arnau de Vilanova and Santa Maria, Lleida, Spain, (2) Translational Research in Respiratory Medicine Group, Lleida, Spain, (3) Lleida Biomedical Research Institute, Lleida, Spain, (4) Centro de Investigación Biomédica en Red (CIBER) of Respiratory Diseases, Institute of Health Carlos III, Madrid, Spain, (5) Intensive Care Department, Vall d’Hebron Hospital Universitari, Shock, Organ Dysfunction and Resuscitation (SODIR) Research Group, Vall d’Hebron Institut de Recerca, Barcelona, Spain, (6) Department of Pulmonary, Hospital Clinic, Universitat de Barcelona, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain, (7) Department of Pulmonary, University and Polytechnic Hospital La Fe, Valencia, Spain, (8) Barcelona Supercomputing Center, Barcelona, Spain, (9) Hospital Universitario de Getafe, Madrid, Spain, (10) Faculty of Medicine, University of Concepción, Concepción, Chile, (11) Department of Clinical Biochemistry and Immunology, Faculty of Pharmacy, Concepción, Chile, (12) Intensive Care Department, Hospital Universitari Arnau de Vilanova de Lleida, Lleida, Spain, (13) Intensive Care Department, Hospital Universitari Santa Maria de Lleida, Lleida, SpainPostprint (published version

    Deep Learning and Statistical Models for Time-Critical Pedestrian Behaviour Prediction

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    The time it takes for a classifier to make an accurate prediction can be crucial in many behaviour recognition problems. For example, an autonomous vehicle should detect hazardous pedestrian behaviour early enough for it to take appropriate measures. In this context, we compare the switching linear dynamical system (SLDS) and a three-layered bi-directional long short-term memory (LSTM) neural network, which are applied to infer pedestrian behaviour from motion tracks. We show that, though the neural network model achieves an accuracy of 80%, it requires long sequences to achieve this (100 samples or more). The SLDS, has a lower accuracy of 74%, but it achieves this result with short sequences (10 samples). To our knowledge, such a comparison on sequence length has not been considered in the literature before. The results provide a key intuition of the suitability of the models in time-critical problems

    Loss of glutathione redox homeostasis impairs proteostasis by inhibiting autophagy-dependent protein degradation

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    In the presence of aggregation-prone proteins, the cytosol and endoplasmic reticulum (ER) undergo a dramatic shift in their respective redox status, with the cytosol becoming more oxidized and the ER more reducing. However, whether and how changes in the cellular redox status may affect protein aggregation is unknown. Here, we show that C. elegans loss-of-function mutants for the glutathione reductase gsr-1 gene enhance the deleterious phenotypes of heterologous human, as well as endogenous worm aggregation-prone proteins. These effects are phenocopied by the GSH-depleting agent diethyl maleate. Additionally, gsr-1 mutants abolish the nuclear translocation of HLH-30/TFEB transcription factor, a key inducer of autophagy, and strongly impair the degradation of the autophagy substrate p62/SQST-1::GFP, revealing glutathione reductase may have a role in the clearance of protein aggregates by autophagy. Blocking autophagy in gsr-1 worms expressing aggregation-prone proteins results in strong synthetic developmental phenotypes and lethality, supporting the physiological importance of glutathione reductase in the regulation of misfolded protein clearance. Furthermore, impairing redox homeostasis in both yeast and mammalian cells induces toxicity phenotypes associated with protein aggregation. Together, our data reveal that glutathione redox homeostasis may be central to proteostasis maintenance through autophagy regulation.Ministerio de Economía y Competitividad BFU2016–78265-P, BFU2016– 79313-P, MDM-2016–0687, BFU2015–64408-PInstituto de Salud Carlos III PI11/ 00072, CPII16/00004, PI14/00949, PI17/0001

    Asymmetric g tensor in low-symmetry two-dimensional hole systems

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    The complex structure of the valence band in many semiconductors leads to multifaceted and unusual properties for spin-3/2 hole systems compared to common spin-1/2 electron systems. In particular, two-dimensional hole systems show a highly anisotropic Zeeman interaction. We have investigated this anisotropy in GaAs/AlAs quantum well structures both experimentally and theoretically. By performing time-resolved Kerr rotation measurements, we found a nondiagonal tensor g that manifests itself in unusual precessional motion, as well as distinct dependencies of hole-spin dynamics on the direction of the magnetic field B. We quantify the individual components of the tensor g for [113]-, [111]-, and [110]grown samples. We complement the experiments by a comprehensive theoretical study of Zeeman coupling in in-plane and out-of-plane fields B. To this end, we develop a detailed multiband theory for the tensor g. Using perturbation theory, we derive transparent analytical expressions for the components of the tensor g that we complement with accurate numerical calculations based on our theoretical framework. We obtain very good agreement between experiment and theory. Our study demonstrates that the tensor g is neither symmetric nor antisymmetric. Opposite off-diagonal components can differ in size by up to an order of magnitude. The tensor g encodes not only the Zeeman energy splitting but also the direction of the axis about which the spins precess in the external field B. In general, this axis is not aligned with B. Hence our study extends the general concept of optical orientation to the regime of nontrivial Zeeman coupling

    From transformation to chronification of migraine: Pathophysiological and clinical aspects

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    Chronic migraine is a neurological disorder characterized by 15 or more headache days per month of which at least 8 days show typical migraine features. The process that describes the development from episodic migraine into chronic migraine is commonly referred to as migraine transformation or chronification. Ample studies have attempted to identify factors associated with migraine transformation fr
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