556 research outputs found

    Autophagy is activated and involved in cell death with participation of cathepsins during stress-induced microspore embryogenesis in barley

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    Microspores are reprogrammed towards embryogenesis by stress. Many microspores die after this stress, limiting the efficiency of microspore embryogenesis. Autophagy is a degradation pathway that plays critical roles in stress response and cell death. In animals, cathepsins have an integral role in autophagy by degrading autophagic material; less is known in plants. Plant cathepsins are papain-like C1A cysteine proteases involved in many physiological processes, including programmed cell death. We have analysed the involvement of autophagy in cell death, in relation to cathepsin activation, during stress-induced microspore embryogenesis in Hordeum vulgare. After stress, reactive oxygen species (ROS) and cell death increased and autophagy was activated, including HvATG5 and HvATG6 up-regulation and increase of ATG5, ATG8, and autophagosomes. Concomitantly, cathepsin L/F-, B-, and H-like activities were induced, cathepsin-like genes HvPap-1 and HvPap-6 were up-regulated, and HvPap-1, HvPap-6, and HvPap-19 proteins increased and localized in the cytoplasm, resembling autophagy structures. Inhibitors of autophagy and cysteine proteases reduced cell death and promoted embryogenesis. The findings reveal a role for autophagy in stress-induced cell death during microspore embryogenesis, and the participation of cathepsins. Similar patterns of activation, expression, and localization suggest a possible connection between cathepsins and autophagy. The results open up new possibilities to enhance microspore embryogenesis efficiency with autophagy and/or cysteine protease modulators.España, MINECO AGL2014-52028-R and AGL2017-82447-

    Advanced design features of Doherty power amplifiers

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    A Doherty power amplifier (DPA) is an effective structure born in 1936 which, after a scarce revival around year 2000), had been strengthened from 2005 because its capability to combine linear amplification with power efficiency. Despite the conceptual simplicity of its basic operation, a lot of practical drawbacks shrink the theoretical behavior, thus leading a significant number of research works to overcome them. The main objective in DPA research is to increase efficiency while maintaining linearity and filling the specified bandwidth. This paper presents a survey of the state of the art of DPA advanced design aspects. After a short review of the DPA operation principles, aspects regarding improvements for linearity, power efficiency and amplification bandwidth are introduced. Besides, some alternative structures and technologies, as well as practical design aspects and some trade-offs which the designer usually has to face are also presented.Peer ReviewedPostprint (published version

    Is the Deficit under Control?

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    According to the 2001 Spanish budgetary previsions, the government deficit is about to disappear. We analyse this matter within a generational accounting framework. Accounting for the recent expansive phase of the economic cycle, we find that current fiscal policy is also intertemporally balanced provided that the favourable present employment situation lasts. However, public finances remain under the pressure of the demographic cycle. Therefore, to achieve fiscal sustainability, the surpluses predicted for the next decades need to be accumulated, in order to finance deficits appearing during the baby-boomers? retirement. The improvement of employment has played an important role in this situation. We extend the standard generational accounting methodology incorporating tax and transfer age profiles by employment status. This permits us to analyse the possible intertemporal impact of several future employment developments. In particular, we assess the fiscal effects of an expected future increase in female labour force participation. We show that this trend does not necessarily improve the intertemporal government budget, as social insurance in Spain is not actuarially fair. Finally, we also assess the impact of a decline in unemployment to the natural rate of unemployment

    Spatiotemporal Precipitation Estimation from Rain Gauges and Meteorological Radar Using Geostatistics

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    [EN] Automatic interpolation of precipitation maps combining rain gauge and radar data has been done in the past but considering only the data collected at a given time interval. Since radar and rain gauge data are collected at short intervals, a natural extension of previous works is to account for temporal correlations and to include time into the interpolation process. In this work, rainfall is interpolated using data from the current time interval and the previous one. Interpolation is carried out using kriging with external drift, in which the radar rainfall estimate is the drift, and the mean precipitation is set to zero at the locations where the radar estimate is zero. The rainfall covariance is modeled as non-stationary in time, and the space system of reference moves with the storm. This movement serves to maximize the collocated correlation between consecutive time intervals. The proposed approach is analyzed for four episodes that took place in Catalonia (Spain). It is compared with three other approaches: (i) radar estimation, (ii) kriging with external drift using only the data from the same time interval, and (iii) kriging with external drift using data from two consecutive time intervals but not accounting for the displacement of the storm. The comparisons are performed using cross-validation. In all four episodes, the proposed approach outperforms the other three approaches. It is important to account for temporal correlation and use a Lagrangian system of coordinates that tracks the rainfall movement.This work has been done in the framework of the Spanish Project FFHazF (CGL2014-60700) and the EC H2020 project ANYWHERE (DRS-1-2015-700099). Thanks are due to the Meteorological Service of Catalonia for providing the radar and rain gauges data used here.Cassiraga, EF.; Gómez-Hernández, JJ.; Berenguer, M.; Sempere-Torres, D.; Rodrigo-Ilarri, J. (2021). Spatiotemporal Precipitation Estimation from Rain Gauges and Meteorological Radar Using Geostatistics. Mathematical Geosciences. 53(4):499-516. https://doi.org/10.1007/s11004-020-09882-1S499516534Aran M, Amaro J, Arús J, Bech J, Figuerola F, Gayà M, Vilaclara E (2009) Synoptic and mesoscale diagnosis of a tornado event in Castellcir, Catalonia, on 18th October 2006. Atmos Res 93:147–160Azimi-Zonooz A, Krajewski W, Bowles D, Seo D (1989) Spatial rainfall estimation by linear and non-linear co-kriging of radar-rainfall and raingage data. Stoch Hydrol Hydraul 3:51–67Bech J, Pascual R, Rigo T, Pineda N, López J, Arús J, Gayá M (2007) An observational study of the 7 September 2005 Barcelona Tornado outbreak. Nat Hazards Earth Syst Sci 7:129–139Bech J, Pineda N, Rigo T, Aran M, Amaro J, Gayà M, Arús J, Montanyà J, van der Velde O (2011) A mediterranean nocturnal heavy rainfall and tornadic event. Part I: overview, damage survey and radar analysis. 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    Improvement of Up-converters linearity for Ka-band operation

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    The application of a digital predistorter to the linearisation of a Ka-band mixer is presented herein. The general objective in the TX design is to get the best trade-off between linearity and costs. This require the most of the simplicity and possibly to take advantage from already existing device without perturbing its other functionalities. After a presentation of the problem and its constraints, we present the digital predistorter, which has been tested and debugged by means of IEEE-488 bus (GPIB) controllable instrumentation (EMA, electronic measuring automation) in order to finally consider its implementation on a fast newgeneration FPGA device. Results show an increment of the linear zone in the up-converter AM-AM curve, of about 15 dB

    Nanoarchitectures Based on Layered Titanosilicates Supported on Glass Fibers: Application to Hydrogen Storage

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    This work reports on the synthesis of nanosheets of layered titanosilicate JDF-L1 supported on commercial E-type glass fibers with the aim of developing novel nanoarchitectures useful as robust and easy to handle hydrogen adsorbents. The preparation of those materials is carried out by hydrothermal reaction from the corresponding gel precursor in the presence of the glass support. Because of the basic character of the synthesis media, silica from the silicate-based glass fibers can be involved in the reaction, cementing its associated titanosilicate and giving rise to strong linkages on the support with the result of very stable heterostructures. The nanoarchitectures built up by this approach promote the growth and disposition of the titanosilicate nanosheets as a house-of-cards radially distributed around the fiber axis. Such an open arrangement represents suitable geometry for potential uses in adsorption and catalytic applications where the active surface has to be available. The content of the titanosilicate crystalline phase in the system represents about 12 wt %, and this percentage of the adsorbent fraction can achieve, at 298 K and 20 MPa, 0.14 wt % hydrogen adsorption with respect to the total mass of the system. Following postsynthesis treatments, small amounts of Pd (<0.1 wt %) have been incorporated into the resulting nanoarchitectures in order to improve their hydrogen adsorption capacity. In this way, Pd-layered titanosilicate supported on glass fibers has been tested as a hydrogen adsorbent at diverse pressures and temperatures, giving rise to values around 0.46 wt % at 298 K and 20 MPa. A mechanism of hydrogen spillover involving the titanosilicate framework and the Pd nanoparticules has been proposed to explain the high increase in the hydrogen uptake capacity after the incorporation of Pd into the nanoarchitecture.We thank the CICYT (Spain, projects MAT2009-09960 and MAT2012-31759), Obra Social la Caixa, Aragon Government (GA-LC-019/2011), ESF, Generalitat Valenciana, and FEDER (PROMETEO/2009/047) for financial support. J.P.-C. is grateful for a Ph.D. grant (FPI, BES-2010-038410) from the Spanish Ministerio de Ciencia e Innovación

    Ethnopharmacological study of medicinal plants with activity on the Central nervous system in the Eastern Region of Cuba

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    In the eastern region of Cuba, there is a traditional use of medicinal plants for various pharmacological purposes, although an inventory of these plant species necessary for the future search for new phytomedicines does not exist in all cases. This is the case for those used to treat central nervous system (CNS) disorders. To evaluate the traditional knowledge in two regions of Eastern Cuba: Santiago de Cuba and Holguín, regarding the use of medicinal plants with sedative, hypnotic, and anxiolytic effects, an ethnopharmacological study was conducted in two health areas of the main municipalities of these two provinces. A total of 400 people were surveyed, performing the socio-demographic characterization of the evaluated population as well as the qualitative characterization and evaluation of quantitative ethnopharmacological indicators such as the use value index and the significant use level of the medicinal plants used. The surveyed population in both provinces was predominantly female and over 60 years old, with a high level of preparation and professional training. A total of 27 plants were reported in the interviews conducted among the 1637 citations obtained, with similar results between the two provinces. The highest number of citations in both regions corresponded to plants used as sedatives, followed by hypnotics, and finally anxiolytics. Among the most used parts of these plants, the use of leaves prepared in the form of infusions predominated. Of the 8 plant species with the highest acceptance by the population, the plants P. neochilus, J. pectoralis, L. inermis, and P. incarnata obtained the best values for the evaluated ethnopharmacological indicators

    Smooth and rough platinum deposits resulting from the electroreduction of hydrous oxide platinum overlayers : A mechanistic approach

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    The electroreduction of thick platinum oxides accumulated by the application of a fast square wave perturbing potential in 0.5 M H2SO4 was studied by using potentiodynamic and potentiostatic techniques complemented with scanning electron miscroscopy. The electroreduction process can be unambigously explained through an instantaneous nucleation and 3-D growth of right circular cones under charge transfer control where diffusion of reacting species to the growing centres is essential for further expansion. The growth mode of the Pt crystallites either smooth or rough depends on the electroreduction conditions. The rought/smooth modes of growth result from the influence of the electric field on the transport of particles in the reaction region and on the supersaturation concentration operating during the electrocrystallization process.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicada
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