Determinación de la longitud de falla y velocidad de ruptura para terremotos de magnitud media

En el proceso de inversión de la función de directividad para la obtención de la longitud de falla y velocidad de ruptura, en el caso de terremotos de magnitud media, es muy dificil obtener ambos parámetros independientemente y deben hacerse hipótesis sobre uno de los dos  parámetros. Proponemos una solución a este problema mediante un proceso iterativo, que iniciamos con un valor hipotético de la velocidad de ruptura. El resultado final resulta ser independiente del valor de partida. Mediante este proceso hemos obtenido la longitud de falla y velocidad de ruptura de dos terremotos, el del  18-nov-1970, ocurrido en la Dorsal Oriental del Pacifico, y el del 4-jul-1966, ocurrido en la Dorsal Centro-Atlántica. Para el sismo del 18-nov-1970 los valores obtenidos en la b= (18+1) km v=(2.3+-0.1) km/s y para el sismo del  4-jul-1966 b=(19+-2) km, v=(2.1+-0.1)kmls. Las desviaciones tipicas de estos parámetros, del orden del 5-10%, son  inferiores a las obtenidas en trabajos previo

Episodios significativamente cálidos y fríos registrados en el Observatorio Fabra, Barcelona

Ponencia presentada en: II Congreso de la Asociación Española de Climatología “El tiempo del clima”, celebrado en Valencia del 7 al 9 de junio de 2001[ES]La serie de temperaturas máxima y mínima diaria del Observatorio Fabra (Barcelona) con datos desde 1917 a 1998, sin interrupciones, permite realizar un estudio detallado de los episodios cálidos y fríos, basado en la teoría del traspaso (crossing theory) de un determinado nivel umbral. Esta última nos conduce a obtener distribuciones estadísticas del número de episodios, de la fecha de inicio de cada uno y de sus magnitudes. Se comprueba que dichas distribuciones se cumplen únicamente para valores del nivel umbral suficientemente apartados de las temperaturas extremas medias diarias. Finalmente se completan estos estudios con otros que nos ayudan a comparar el comportamiento de los episodios cálidos con el de los episodios fríos.[EN]A long series of maximum and minimum daily temperatures recorded at Fabra Observatory (Barcelona) from 1917 to 1998, without lags, permits a detailed study of hot and cold spells, which is based on the crossing theory. This theory leads us to obtain statistical distributions quantifying probabilities concerning the number of lot and cold events per year, the starting date and the magnitude of a spell. It slould be stressed that the statistical distributions describe well the empirical determinations only for threshold levels significantly distant from mean extreme temperatures values. Finally, other studies are included in order to stablish a comparative analysis between hot and cold spells

Modelos estadísticos para el análisis de las anomalías pluviométricas en la ciudad de Barcelona

Ponencia presentada en: I Congreso de la Asociación Española de Climatología “La climatología española en los albores del siglo XXI”, celebrado en Barcelona del 1 al 3 de diciembre de 1999.[ES]Las anomalías mensuales de precipitación en la ciudad de Barcelona se han analizado, desde un punto de vista estadístico, mediante la distribución Gamma y el modelo de Poisson, pudiéndose evaluar las probabilidades relacionadas con la repetición de largos episodios de déficit o exceso de precipitación y sus periodos de retorno. Los datos utilizados consisten en totales mensuales de precipitación registrados sin interrupción a lo largo de 128 años.[EN]Rainfall anomaly patterns for the city of Barcelona are analysed from a statistical point of view. The database for the study consists of monthly amounts recorded along 128 years without interruption. Two hypothesis and the Gamma distribution lead to quantify, by means of a Poisson model, probabilities concerning repeated long episodes with rainfall shortage or excess, and their return periods

Single-molecule tracking in live cells reveals distinct target-search strategies of transcription factors in the nucleus

Gene regulation relies on transcription factors (TFs) exploring the nucleus searching their targets. So far, most studies have focused on how fast TFs diffuse, underestimating the role of nuclear architecture. We implemented a single-molecule tracking assay to determine TFs dynamics. We found that c-Myc is a global explorer of the nucleus. In contrast, the positive transcription elongation factor P-TEFb is a local explorer that oversamples its environment. Consequently, each c-Myc molecule is equally available for all nuclear sites while P-TEFb reaches its targets in a position-dependent manner. Our observations are consistent with a model in which the exploration geometry of TFs is restrained by their interactions with nuclear structures and not by exclusion. The geometry-controlled kinetics of TFs target-search illustrates the influence of nuclear architecture on gene regulation, and has strong implications on how proteins react in the nucleus and how their function can be regulated in space and time.Nikon France (Research contract)France. Agence nationale de la recherche (PCV DYNAFT 08-PCVI-0013)France. Agence nationale de la recherche (DynamIC ANR-12-BSV5-0018)Fondation pour la recherche médicaleNetherlands Organization for Scientific Research (Rubicon fellowship

Extracellular Spermine Triggers a Rapid Intracellular Phosphatidic Acid Response in Arabidopsis, Involving PLDδ Activation and Stimulating Ion Flux

Polyamines, such as putrescine (Put), spermidine (Spd), and spermine (Spm), are low-molecular-weight polycationic molecules found in all living organisms. Despite the fact that they have been implicated in various important developmental and adaptative processes, their mode of action is still largely unclear. Here, we report that Put, Spd, and Spm trigger a rapid increase in the signaling lipid, phosphatidic acid (PA) in Arabidopsis seedlings but also mature leaves. Using time-course and dose-response experiments, Spm was found to be the most effective; promoting PA responses at physiological (low μM) concentrations. In seedlings, the increase of PA occurred mainly in the root and partly involved the plasma membrane polyamine-uptake transporter (PUT), RMV1. Using a differential 32Pi-labeling strategy combined with transphosphatidylation assays and T-DNA insertion mutants, we found that phospholipase D (PLD), and in particular PLDδ was the main contributor of the increase in PA. Measuring non-invasive ion fluxes (MIFE) across the root plasma membrane of wild type and pldδ-mutant seedlings, revealed that the formation of PA is linked to a gradual- and transient efflux of K+. Potential mechanisms of how PLDδ and the increase of PA are involved in polyamine function is discussed

Single-molecule tracking in live cells reveals distinct target-search strategies of transcription factors in the nucleus

Gene regulation relies on transcription factors (TFs) exploring the nucleus searching their targets. So far, most studies have focused on how fast TFs diffuse, underestimating the role of nuclear architecture. We implemented a single-molecule tracking assay to determine TFs dynamics. We found that c-Myc is a global explorer of the nucleus. In contrast, the positive transcription elongation factor P-TEFb is a local explorer that oversamples its environment. Consequently, each c-Myc molecule is equally available for all nuclear sites while P-TEFb reaches its targets in a position-dependent manner. Our observations are consistent with a model in which the exploration geometry of TFs is restrained by their interactions with nuclear structures and not by exclusion. The geometry-controlled kinetics of TFs target-search illustrates the influence of nuclear architecture on gene regulation, and has strong implications on how proteins react in the nucleus and how their function can be regulated in space and time

Epilepsy in neurodegenerative diseases: related drugs and molecular pathways

Epilepsy is a chronic disease of the central nervous system characterized by an electrical imbalance in neurons. It is the second most prevalent neurological disease, with 50 million people affected around the world, and 30% of all epilepsies do not respond to available treatments. Currently, the main hypothesis about the molecular processes that trigger epileptic seizures and promote the neurotoxic effects that lead to cell death focuses on the exacerbation of the glutamate pathway and the massive influx of Ca2+ into neurons by different factors. However, other mechanisms have been proposed, and most of them have also been described in other neurodegenerative diseases, such as Alzheimers disease, Parkinsons disease, Huntingtons disease, or multiple sclerosis. Interestingly, and mainly because of these common molecular links and the lack of effective treatments for these diseases, some antiseizure drugs have been investigated to evaluate their therapeutic potential in these pathologies. Therefore, in this review, we thoroughly investigate the common molecular pathways between epilepsy and the major neurodegenerative diseases, examine the incidence of epilepsy in these populations, and explore the use of current and innovative antiseizure drugs in the treatment of refractory epilepsy and other neurodegenerative diseases.Acknowledges the support of the Spanish Ministry of Science, Innovation and Universities under the grant Juan de la Cierva (FJC2018-036012-I). Authors acknowledge the support of the Instituto de Salud Carlos III (ISCIII) Acción Estratégica en Salud, integrated into the Spanish National R+D+I Plan and financed by ISCIII Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER “Una manera de hacer Europa”) grant PI17/01474 awarded to M.B. Boada and grant PI19/00335 awarded to M.M.; M.E. acknowledges the support of the Spanish Ministry of Economy and Competitiveness under the project SAF2017- 84283-R, and CIBERNED under project CB06/05/0024. E.B.S. acknowledges the support of the Portuguese Science and Technology Foundation (FCT) for the strategic fund (UIDB/04469/2020). A.R. acknowledges the support of CIBERNED (Instituto de Salud Carlos III (ISCIII)), the EU/EFPIA Innovative Medicines Initiative Joint Undertaking, ADAPTED Grant Nº 115975, from EXIT project, EU Euronanomed3 Program JCT2017 Grant Nº AC17/00100, from PREADAPT project. Joint Program for Neurodegenerative Diseases (JPND) Grant No. AC19/00097, and from grants PI13/02434, PI16/01861 BA19/00020, and PI19/01301. Acción Estratégica en Salud, integrated in the Spanish National RCDCI Plan and financed by Instituto de Salud Carlos III (ISCIII)- Subdirección General de Evaluación and the Fondo Europeo de Desarrollo Regional (FEDER—“Una manera de Hacer Europa”), by Fundación bancaria “La Caixa” and Grífols SA (GR@ACE project)info:eu-repo/semantics/publishedVersio