40 research outputs found

    Modelo de cabalgamiento profundo para el Alto Atlas (Marruecos). Implicaciones sísmicas en la zona de colisión entre Eurasia y Africa

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    Previous crustal models of the High Atlas suppose the existence of a mid-crustal detachment where all the surface thrusts merged and below which the lower crust was continuous. However, both seismic refraction data and gravity modeling detected a jump in crustal thickness between the High Atlas and the northern plains. Here we show that this rapid and vertical jump in the depth of Moho discontinuity suggests that a thrust fault may penetrate the lower crust and offset the Moho (deep-rooted “thick skinned” model). The distribution of Neogene and Quaternary volcanisms along and at the northern part of the High Atlas lineament can be related to the beginning of a partial continental subduction of the West African plate to the north underneath Moroccan microplate. Allowing from the complex problem of the plate boundary in the western zone of the Mediterranean, we propose to interpret the South-Atlasic fault zone as the actual northwestern boundary of the stable part of the African plate rather than the Azores-Gibraltar fault currently used.Los modelos geodinámicos existentes sobre la estructura profunda del alto Atlas suponen la existencia de un despegue medio-cortical donde convergen los cabalgamientos superficiales y bajo el cual la corteza inferior es continua. Los datos de sísmica de refracción y gravimetría, sin embargo, indican la existencia de una discontinuidad en el grosor de la corteza (profundidad del Moho) bajo el Alto Atlas. En este artículo ponemos de manifiesto que este salto rápido en la profundidad del Moho puede ser causado por un cabalgamiento que penetra la corteza inferior, desplazando la base de la misma (“deeprooted thick skinned model”). La distribución del volcanismo Neógeno y Cuaternario a lo largo de y al norte de la alineación del Alto Atlas pueden estar relacionados con el comienzo de una subducción continental parcial de la placa Africana occidental hacia el norte, bajo la microplaca marroquí. La expresión en superficie de este cabalgamiento, la zona de falla sud-atlásica, refleja la influencia de una sutura continental heredada de orogenias anteriores (panafricana, hercínica y rifting Jurásico). Por tanto, proponemos que este frente heredado representa el límite meridional de la zona de colisión mediterránea y el margen noroccidental de la porción estable de la placa africana

    Role of PACAP and VIP Signalling in Regulation of Chondrogenesis and Osteogenesis

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    Pituitary adenylate cyclase activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) are multifunctional proteins that can regulate diverse physiological processes. These are also regarded as neurotrophic and anti-inflammatory substances in the CNS, and PACAP is reported to prevent harmful effects of oxidative stress. In the last decade more and more data accumulated on the similar function of PACAP in various tissues, but its cartilage- and bone-related presence and functions have not been widely investigated yet. In this summary we plan to verify the presence and function of PACAP and VIP signalling tool kit during cartilage differentiation and bone formation. We give evidence about the protective function of PACAP in cartilage regeneration with oxidative or mechanically stress and also with the modulation of PACAP signalling in vitro in osteogenic cells. Our observations imply the therapeutic perspective that PACAP might be applicable as a natural agent exerting protecting effect during joint inflammation and/or may promote cartilage regeneration during degenerative diseases of articular cartilage

    Prospect of vasoactive intestinal peptide therapy for COPD/PAH and asthma: a review

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    There is mounting evidence that pulmonary arterial hypertension (PAH), asthma and chronic obstructive pulmonary disease (COPD) share important pathological features, including inflammation, smooth muscle contraction and remodeling. No existing drug provides the combined potential advantages of reducing vascular- and bronchial-constriction, and anti-inflammation. Vasoactive intestinal peptide (VIP) is widely expressed throughout the cardiopulmonary system and exerts a variety of biological actions, including potent vascular and airway dilatory actions, potent anti-inflammatory actions, improving blood circulation to the heart and lung, and modulation of airway secretions. VIP has emerged as a promising drug candidate for the treatment of cardiopulmonary disorders such as PAH, asthma, and COPD. Clinical application of VIP has been limited in the past for a number of reasons, including its short plasma half-life and difficulty in administration routes. The development of long-acting VIP analogues, in combination with appropriate drug delivery systems, may provide clinically useful agents for the treatment of PAH, asthma, and COPD. This article reviews the physiological significance of VIP in cardiopulmonary system and the therapeutic potential of VIP-based agents in the treatment of pulmonary diseases

    Variational Iteration Method and Differential Transformation Method for Solving the SEIR Epidemic Model

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    The aim of the present study is to analyze and find a solution for the model of nonlinear ordinary differential equations (ODEs) describing the so-called coronavirus (COVID-19), a deadly and most parlous virus. The mathematical model based on four nonlinear ODEs is presented, and the corresponding numerical results are studied by applying the variational iteration method (VIM) and differential transformation method (DTM)

    Thermochemical treatment of olive mill solid waste and olive mill wastewater Pyrolysis kinetics

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    In olive-oil-producing countries, large amounts of waste material are generated as by-product for which there is no ready use and in some cases may have a negative value because of the cost of disposal. Most of these countries depend on fossil fuels for their energy uses, and olive mill wastes can be used to supplement such energy sources using thermochemical conversion processes such as pyrolysis. However, efficient operation of thermochemical conversion systems requires a thorough understanding of the influence of the composition and thermal properties of these by-products on their behaviour during the conversion process. In this study, the thermal behaviour of two olive mill wastes samples (olive mill solid waste: OMSW, and concentrated olive mill wastewater: COMWW) was examined at different heating rates ranging from 5 to 50 A degrees C min(-1) in inert atmosphere using the technique of thermogravimetric analysis. As the increment of heating rates, the variations of characteristic parameters from the TG-DTG curves were determined. The initial temperature of degradation is higher in OMSW, which present a high amount of cellulose in comparison with COMWW. Three methods were used for the determination of kinetic reaction parameters: Friedman, Ozawa-Flynn-Wall and Vyazovkin methods. The results showed that apparent activation energy obtained for the decomposition of hemicelluloses and cellulose derived from OMSW was given as 150-176 and 210.5-235.7 kJ mol(-1), while for COMWW, the values were 133-145 and 255-275 kJ mol(-1), respectively
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