548 research outputs found

    Holistic management approach as a tool for dehesa/montado restoration

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    PosterDehesa/montado can be defined as a multi-purpose agroforestry system with scattered oak trees. This ecosystem covers an estimated 3.1 million ha and is the most extended silvopastoral system and the largest High Nature Value Farming System in Europe. However, the sustainability of dehesas/montados has been questioned in recent years because of trends towards more intensive and simplified management, which in turn have led to changes in vegetation and soil properties and increased soil erosion rates. Holistic Management approach, based on time-controlled grazing systems, not only increases productivity but also implies ecosystem improvements: soil properties (soil structure, amount of organic matter, water efficiency, and availability soil nutrients) and pasture species cover and composition. McCoster (2000) has described a synergistic effect between a cell grazing (similar to HM) and trees regeneration in Australia. The main goal of this study is to evaluate the effect of the Holistic Management Grazing Approach on the soil properties, trees recovery, pasture cover, biodiversity and productivity opposite to nowadays continuous grazing management and different pasture innovations in Spanish and Portuguese dehesa/montado farms

    Investigation and optimisation of a multipass resonant photoacoustic cell at high absorption levels

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    A theoretical and experimental investigation of photoacoustic (PA) signals in a resonant multipass PA cell with high background absorption (up to 29m-1) is presented. An analogous electric transmission line model including discontinuity inductances at cross section changes was used to model the first longitudinal acoustic mode of the multipass PA cell equipped with two buffer volumes. This model was validated with experimentally obtained results and used to predict the behaviour of the PA cell for different multipass arrangements and different buffer volume diameters. The highest PA signal is obtained for high pass number and large buffer radius. Increasing the absorption coefficient of the medium enhances the PA signal until a maximum is reached, leading to a minimum for the PA signal sensitivity. For a given background absorption, the number of passes required to maximise the sensitivity depends on the absorption coefficient. The model allows the determination of the best-suited number of passes for a given absorption coefficient and cell geometr

    Modulation of Host Immunity by Human Respiratory Syncytial Virus Virulence Factors: A Synergic Inhibition of Both Innate and Adaptive Immunity

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    Indexación: Web of Science; Scopus.The Human Respiratory Syncytial Virus (hRSV) is a major cause of acute lower respiratory tract infections (ARTIs) and high rates of hospitalizations in children and in the elderly worldwide. Symptoms of hRSV infection include bronchiolitis and pneumonia. The lung pathology observed during hRSV infection is due in part to an exacerbated host immune response, characterized by immune cell infiltration to the lungs. HRSV is an enveloped virus, a member of the Pneumoviridae family, with a non-segmented genome and negative polarity-single RNA that contains 10 genes encoding for 11 proteins. These include the Fusion protein (F), the Glycoprotein (G), and the Small Hydrophobic (SH) protein, which are located on the virus surface. In addition, the Nucleoprotein (N), Phosphoprotein (P) large polymerase protein (L) part of the RNA-dependent RNA polymerase complex, the M2-1 protein as a transcription elongation factor, the M2-2 protein as a regulator of viral transcription and (M) protein all of which locate inside the virion. Apart from the structural proteins, the hRSV genome encodes for the non-structural 1 and 2 proteins (NS1 and NS2). HRSV has developed different strategies to evade the host immunity by means of the function of some of these proteins that work as virulence factors to improve the infection in the lung tissue. Also, hRSV NS-1 and NS-2 proteins have been shown to inhibit the activation of the type I interferon response. Furthermore, the hRSV nucleoprotein has been shown to inhibit the immunological synapsis between the dendritic cells and T cells during infection, resulting in an inefficient T cell activation. Here, we discuss the hRSV virulence factors and the host immunological features raised during infection with this virus.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00367/ful

    Euclidean Wormholes in String Theory

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    We show that toroidal compactification of type II string theory to six dimensions admits axionic euclidean wormhole solutions. These wormholes can be inserted into AdS3×S3×T4AdS_3 \times S^3 \times T^4 backgrounds, which have a well-defined CFT dual. AdS/CFT duality then suggests that the wormhole solutions cannot be interpreted using α\alpha parameters as originally suggested by Coleman.Comment: 18 pages. ver. 2: typos corrected, references adde
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