1,124 research outputs found

    The Gallecs trial, a mid-term experiment on reduced tillage, fertilisation and green manure in Mediterranean dryland arable cropping systems

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    Conservation agriculture and organic farming are two alternative strategies aimed at improving soil fertility in arable cropping systems through reducing tillage intensity, maintaining year-round soil cover and increasing nutrient recycling, using farmyard and green manures. However, the reduction of tillage intensity can increase weed infestation and decrease nutrient availability. The mid-term "Gallecs" trial (Catalonia) was established in autumn 2011 at Gallecs, a periurban agricultural area near Barcelona. The effects of tillage (mouldboard versus chisel ploughing), fertilisation by farmyard manure (without versus with) and green manure (without versus with) on soil fertility indicators, weed abundance and grain crop yields were studied in a 4-years cereal-legume rotation for human consumption under organic farming conditions in the Mediterranean region (Catalonia, Spain)

    A Robotic Solution for the Restoration of Fresco Paintings

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    In this paper, a service robot solution is presented for the analysis, surveying and restoration of fresco paintings. The proposed design approach integrates robot design and restoration operation. It aims to merge them into a feasible solution that can be both practical and feasible for restorers. The simulation results are reported to show a successful design solution, which has been conceived with the constraints of a low-cost user-oriented design and the consideration of cultural heritage

    The REDMAAS 2012 SMPS+UFP intercomparison campaign

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    Resumen de la comunicación oral presentada en: 1st Iberian Meeting on Aerosol Science and Technology – RICTA 2013, celebrado del 1 al 3 de julio de 2013 en Évora, Portugal.This network is financed by the Ministry of Science and Innovation (CGL2011-15008-E & CGL2011-27020)

    The REDMAAS 2014 intercomparison campaign: CPC, SMPS, UFPM and neutralizers

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    Ponencia presentada en:2nd Iberian Meeting on Aerosol Science and Technology (RICTA 2014) celebrado en Tarragona del 7 al 9 de julio de 2014.The Spanish network on environmental DMAs (Red Española de DMAs Ambientales, REDMAAS), working since 2010, is currently formed by six groups involved in the measurement of atmospheric aerosol size distributions by means of Differential Mobility Analyzers (DMAs). One of its activities is an annual intercomparison of mobility size spectrometers (SMPS and UFPM). In this work we show the results obtained in the 2014 campaign: the verification of DMA calibrations with latex, the results of the CPC and SMPS + UFPM intercomparisons, and a comparison of the new TSI 3087 X-ray and the former TSI 3077 85Kr neutralizers. The concentrations measured by different types of CPC were within the range of 10% of the average value. CPCs working at higher flow rates measured slightly higher concentrations, probably related to the smaller losses in the lines. All the SMPS worked at the same sampling and sheath flow rates (1:10 lpm). Four of the SMPS gave very good results for particles larger than 20 nm. The UFPM measured particle number concentrations in the average +/-10% band measured by the SMPS. Instruments working with the X-ray neutralizer measured higher concentrations than with the 85Kr neutralizers. This could mean that particle losses are smaller inside this neutralizer.This work has been financed by the Ministry of Science and Innovation (CGL2011-15008-E, CGL2010-1777, CGL2011-27020 & CGL2011-26259)

    Atmospheric particle size distributions in the Spanish Network of Environmental DMAs (REDMAAS)

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    The present work is a first approach to the study of the spatio-temporal variability of the submicrometer atmospheric aerosol in Spain. The aerosol measurements have been obtained simultaneously at seven monitoring stations that compose the REDMAAS network during two measurement campaigns corresponding to summer and winter seasons. In both summer and winter periods those measurement stations with a direct influence of anthropogenic emissions recorded the highest concentrations of particle number. In the summer campaign, the average daily pattern of the aerosol size distribution in the traffic and background urban stations was conditioned by the traffic emissions and secondary aerosol formation through photochemical reactions (new particle formation events, NPF). However, the secondary aerosol had a higher contribution to the aerosol total number concentration in the rural background and high-altitude stations. In the winter campaign, in all sampling sites with the exception of Izaña station, the traffic and domestic activity emissions had a greater contribution than secondary aerosol formation on particle number total concentration. New particle formation events were identified at all sites during the summer period, and at sites without direct influence of anthropogenic emissions during the winter campaign. Some aerosol shrinkage processes were also observed at the Madrid and El Arenosillo stations.This work has been financed by the Ministry of Science and Innovation (CGL2011-15008-E, CGL2010-1777, CGL2011-27020, CGL2014-52877-R & CGL2014-55230-R), Xunta de Galicia (GRC2013-047 potentially cofounded by ERDF) and the European Union Seventh Framework Programme (FP7/2007–2013) ACTRIS under grant agreement no. 262254

    Discovery of a Metal-Poor Field Giant with a Globular Cluster Second-Generation Abundance Pattern

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    We report on the detection, from observations obtained with the Apache Point Observatory Galactic Evolution Experiment spectroscopic survey, of a metal-poor ([Fe/H] = −1.3 dex) field giant star with an extreme Mg–Al abundance ratio ([Mg/Fe] = −0.31 dex; [Al/Fe] = 1.49 dex). Such low Mg/Al ratios are seen only among the second-generation population of globular clusters (GCs) and are not present among Galactic disk field stars. The light-element abundances of this star, 2M16011638-1201525, suggest that it could have been born in a GC. We explore several origin scenarios, studying the orbit of the star in particular to check the probability of its being kinematically related to known GCs. We performed simple orbital integrations assuming the estimated distance of 2M16011638-1201525 and the available six-dimensional phase-space coordinates of 63 GCs, looking for close encounters in the past with a minimum distance approach within the tidal radius of each cluster. We found a very low probability that 2M16011638-1201525 was ejected from most GCs; however, we note that the best progenitor candidate to host this star is GC ω Centauri (NGC 5139). Our dynamical investigation demonstrates that 2M16011638-1201525 reaches a distance Zmax<3kpc| {Z}_{\max }| \lt 3\,\mathrm{kpc} from the Galactic plane and minimum and maximum approaches to the Galactic center of R min < 0.62 kpc and R max < 7.26 kpc in an eccentric (e ~ 0.53) and retrograde orbit. Since the extreme chemical anomaly of 2M16011638-1201525 has also been observed in halo field stars, this object could also be considered a halo contaminant, likely to have been ejected into the Milky Way disk from the halo. We conclude that 2M16011638-20152 is also kinematically consistent with the disk but chemically consistent with halo field stars

    Magnetic fields inferred by Solar Orbiter: A comparison between SO/PHI-HRT and SDO/HMI

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    The High Resolution Telescope (HRT) of the Polarimetric and Helioseismic Imager on board the Solar Orbiter spacecraft (SO/PHI) and the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) both infer the photospheric magnetic field from polarised light images. SO/PHI is the first magnetograph to move out of the Sun--Earth line and will provide unprecedented access to the Sun's poles. This provides excellent opportunities for new research wherein the magnetic field maps from both instruments are used simultaneously. We aim to compare the magnetic field maps from these two instruments and discuss any possible differences between them. We used data from both instruments obtained during Solar Orbiter's inferior conjunction on 7 March 2022. The HRT data were additionally treated for geometric distortion and degraded to the same resolution as HMI. The HMI data were re-projected to correct for the 33^{\circ} separation between the two observatories. SO/PHI-HRT and HMI produce remarkably similar line-of-sight magnetograms, with a slope coefficient of 0.970.97, an offset below 11 G, and a Pearson correlation coefficient of 0.970.97. However, SO/PHI-HRT infers weaker line-of-sight fields for the strongest fields. As for the vector magnetic field, SO/PHI-HRT was compared to both the 720720-second and 9090-second HMI vector magnetic field: SO/PHI-HRT has a closer alignment with the 9090-second HMI vector. In the weak signal regime (<600< 600 G), SO/PHI-HRT measures stronger and more horizontal fields than HMI, very likely due to the greater noise in the SO/PHI-HRT data. In the strong field regime (600\gtrsim 600 G), HRT infers lower field strengths but with similar inclinations (a slope of 0.920.92) and azimuths (a slope of 1.021.02). The slope values are from the comparison with the HMI 9090-second vector.Comment: 10 pages, 5 figures, accepted for publication in A&A; manuscript is a part of Astronomy & Astrophysics special issue: Solar Orbiter First Results (Nominal Mission Phase

    The Impact of Culturing the Organ Preservation Fluid on Solid Organ Transplantation: A Prospective Multicenter Cohort Study

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    Background. We analyzed the prevalence, etiology, and risk factors of culture-positive preservation fluid and their impact on the management of solid organ transplant recipients. Methods. From July 2015 to March 2017, 622 episodes of adult solid organ transplants at 7 university hospitals in Spain were prospectively included in the study. Results. The prevalence of culture-positive preservation fluid was 62.5% (389/622). Nevertheless, in only 25.2% (98/389) of the cases were the isolates considered ?high risk? for pathogenicity. After applying a multivariate regression analysis, advanced donor age was the main associated factor for having culture-positive preservation fluid for high-risk microorganisms. Preemptive antibiotic therapy was given to 19.8% (77/389) of the cases. The incidence rate of preservation fluid?related infection was 1.3% (5 recipients); none of these patients had received preemptive therapy. Solid organ transplant (SOT) recipients with high-risk culture-positive preservation fluid receiving preemptive antibiotic therapy presented both a lower cumulative incidence of infection and a lower rate of acute rejection and graft loss compared with those who did not have high-risk culture-positive preservation fluid. After adjusting for age, sex, type of transplant, and prior graft rejection, preemptive antibiotic therapy remained a significant protective factor for 90-day infection. Conclusions. The routine culture of preservation fluid may be considered a tool that provides information about the contamination of the transplanted organ. Preemptive therapy for SOT recipients with high-risk culture-positive preservation fluid may be useful to avoid preservation fluid?related infections and improve the outcomes of infection, graft loss, and graft rejection in transplant patients

    Stereoscopic disambiguation of vector magnetograms: first applications to SO/PHI-HRT data

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    Spectropolarimetric reconstructions of the photospheric vector magnetic field are intrinsically limited by the 180^\circ-ambiguity in the orientation of the transverse component. So far, the removal of such an ambiguity has required assumptions about the properties of the photospheric field, which makes disambiguation methods model-dependent. The basic idea is that the unambiguous line-of-sight component of the field measured from one vantage point will generally have a non-zero projection on the ambiguous transverse component measured by the second telescope, thereby determining the ``true'' orientation of the transverse field. Such an idea was developed and implemented in the Stereoscopic Disambiguation Method (SDM), which was recently tested using numerical simulations. In this work we present a first application of the SDM to data obtained by the High Resolution Telescope (HRT) onboard Solar Orbiter during the March 2022 campaign, when the angle with Earth was 27 degrees. The method is successfully applied to remove the ambiguity in the transverse component of the vector magnetogram solely using observations (from HRT and from the Helioseismic and Magnetic Imager), for the first time. The SDM is proven to provide observation-only disambiguated vector magnetograms that are spatially homogeneous and consistent. A discussion about the sources of error that may limit the accuracy of the method, and of the strategies to remove them in future applications, is also presented.Comment: 32 pages, 12 figures, accepted in A&A on 09/07/202

    Vertical and horizontal distribution of regional new particle formation events in Madrid

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    The vertical profile of new particle formation (NPF) events was studied by comparing the aerosol size number distributions measured aloft and at surface level in a suburban environment in Madrid, Spain, using airborne instruments. The horizontal distribution and regional impact of the NPF events was investigated with data from three urban, urban background, and suburban stations in the Madrid metropolitan area. Intensive regional NPF episodes followed by particle growth were simultaneously recorded at three stations in and around Madrid during a field campaign in July 2016. The urban stations presented larger formation rates compared to the suburban station. Condensation and coagulation sinks followed a similar evolution at all stations, with higher values at urban stations. However, the total number concentration of particles larger than 2.5 nm was lower at the urban station and peaked around noon, when black carbon (BC) levels are at a minimum. The vertical soundings demonstrated that ultrafine particles (UFPs) are formed exclusively inside the mixed layer. As convection becomes more effective and the mixed layer grows, UFPs are detected at higher levels. The morning soundings revealed the presence of a residual layer in the upper levels in which aged particles (nucleated and grown on previous days) prevail. The particles in this layer also grow in size, with growth rates significantly smaller than those inside the mixed layer. Under conditions with strong enough convection, the soundings revealed homogeneous number size distributions and growth rates at all altitudes, which follow the same evolution at the other stations considered in this study. This indicates that UFPs are detected quasi-homogenously in an area spanning at least 17 km horizontally. The NPF events extend over the full vertical extension of the mixed layer, which can reach as high as 3000 m in the area, according to previous studies. On some days a marked decline in particle size (shrinkage) was observed in the afternoon, associated with a change in air masses. Additionally, a few nocturnal nucleation-mode bursts were observed at the urban stations, for which further research is needed to elucidate their origin.Peer reviewe
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