1,045 research outputs found

    Assessing economic impacts of deficit irrigation as related to water productivity and water costs

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    Research Paper:SW-Soil and WaterThis study aims at assessing the feasibility of deficit irrigation of maize, wheat and sunflower through an analysis of the economic water productivity (EWP). It focuses on selected sprinkler-irrigated fields in Vigia Irrigation District, Southern Portugal. Various scenarios of water deficits and water availability were considered. Simulations were performed for average, high and very high climatic demand. The potential crop yields were estimated from regional climatic data and local information. Using field collected data on yield values, production costs, water costs, commodity prices and irrigation performance, indicators on EWP were calculated. Results show that a main bottleneck for adopting deficit irrigation is the presently low performance of the irrigation systems used in the considered fields, which leads to high water use and low EWP. Decreasing water use through deficit irrigation also decreases the EWP. Limited water deficits for maize are likely to be viable when the irrigation performance is improved if water prices do not increase much, and the commodity price does not return to former low levels. The sunflower crop, despite lower sensitivity to water deficits than maize, does not appear to be a viable solution to replace maize when water restrictions are high; however it becomes an attractive crop if recently high commodity prices are maintained. With improved irrigation performance, wheat deficit irrigation is viable including when full water costs are applied, if former low prices are not returned to. However, under drought conditions full water costs are excessive. Thus, adopting deficit irrigation requires not only an appropriate irrigation scheduling but higher irrigation performance, and that the application of a water prices policy would be flexible, thus favouring the improvement of the irrigation systems

    The upper Hauterivian Barremian (Lower Cretaceous) Arrifes section (Algarve Basin, Southern Portugal): a palynostratigraphic and palaeoenvironmental approach

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    ABSTRACT: Integrated sedimentological, palynological, and palynofacies analyses of the Arrifes section in the central Algarve Basin (southern Portugal) provided new information on the age and environments of this Lower Cretaceous sequence. The sedimentary succession at the Arrifes section consists of fossiliferous interbedded limestones, marly limestones, and marls, dated as latest Hauterivian to late Barremian age (Lower Cretaceous) based on key dinoflagellate taxa. During this interval, the Arrifes area records climatic shifts and, multiple sea-level fluctuations; overall deposition was in shallow subtidal to intertidal settings, with deposition of carbonate and marly sediments. During the latest Hauterivian to earliest Barremian interval, an evident sea-level fall culminated in the subaerial exposure of the local carbonate ramp with increased influx of clastic sediments. However, during the Barremian, both sedimentological and palynological analyses suggest an overall deepening of the water depth towards the top of the section. These overall increase in the water column are confirmed by oscillation of terrestrial/marine palynomorph groups and supported by dinosaur track levels at the top of the succession; the latter indicate that sedimentation occurred in intertidal to subtidal environments. Finally, an attempt was made to correlate the Arrifes section with other sections from the Algarve Basin, as well as with broader region. These new data suggest a setting in the Tethyan basin influenced during the latest Hauterivian to the end of the Barremian. These new data allow local correlations and new palynological ages and paleoenvironmental interpretations for the Lower Cretaceous succession of the Algarve Basin.info:eu-repo/semantics/publishedVersio

    The upper Hauterivian–Barremian (Lower Cretaceous) Arrifes section (Algarve Basin, Southern Portugal): A palynostratigraphic and palaeoenvironmental approach

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    Integrated sedimentological, palynological, and palynofacies analyses of the Arrifes section in the central Algarve Basin (southern Portugal) provided new information on the age and environments of this Lower Cretaceous sequence. The sedimentary succession at the Arrifes section consists of fossiliferous inter-bedded limestones, marly limestones, and marls, dated as latest Hauterivian to late Barremian age (Lower Cretaceous) based on key dinoflagellate taxa. During this interval, the Arrifes area records cli-matic shifts and, multiple sea-level fluctuations; overall deposition was in shallow subtidal to intertidal settings, with deposition of carbonate and marly sediments. During the latest Hauterivian to earliest Barremian interval, an evident sea-level fall culminated in the subaerial exposure of the local carbonate ramp with increased influx of clastic sediments. However, during the Barremian, both sedimentological and palynological analyses suggest an overall deepening of the water depth towards the top of the section. These overall increase in the water column are confirmed by oscillation of terrestrial/marine palynomorph groups and supported by dinosaur track levels at the top of the succession; the latter indicate that sedimentation occurred in intertidal to subtidal environments. Finally, an attempt was made to correlate the Arrifes section with other sections from the Algarve Basin, as well as with broader region. These new data suggest a setting in the Tethyan basin influenced during the latest Hauterivian to the end of the Barremian. These new data allow local correlations and new palynological ages and paleoenvironmental interpretations for the Lower Cretaceous succession of the Algarve Basin.(c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).info:eu-repo/semantics/publishedVersio

    Magnetic vortex-like excitations on a sphere

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    We study magnetic vortex-like solutions lying on the spherical surface. The simplest cylindrically symmetric vortex presents two cores (instead of one, like in open surfaces) with same charge, so repealing each other. However, the net vorticity is computed to vanish in accordance with Gauss theorem. We also address the problem of a flat plane in which a conical, a pseudospherical and a hemispherical segments were incorporated. In this case, if we allow the vortex to move without appreciable deformation in this support, then it is attracted by the conical apex and by the pseudosphere as well, while it is repealed by the hemisphere. This suggests that such surfaces could be viewed as pinning and depinning geometries for those excitations. Spherical harmonics coreless solutions are discussed within some details.Comment: 15 pages, 8 .eps figures, typed in tex. Version accepted in Physics Letters A (2007), please see DOI

    <i>Vibrio neptunius</i> sp. nov., <i>Vibrio brasiliensis</i> sp. nov. and <i>Vibrio xuii</i> sp. nov., isolated from the marine aquaculture environment (bivalves, fish, rotifers and shrimps)

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    The fluorescent amplified fragment length polymorphism (FAFLP) groups A5 (21 isolates), A8 (6 isolates) and A23 (3 isolates) distinguished in an earlier paper (Thompson et al., Syst Appl Microbiol 24, 520-538, 2001) were examined in more depth. These three groups were phylogenetically related to Vibrio tubiashii, but DNA-DNA hybridization experiments proved that the three AFLP groups are in fact novel species. Chemotaxonomic and phenotypic analyses further revealed several differences among the 30 isolates and known Vibrio species. It is proposed to accommodate these isolates in three novel species, namely Vibrio neptunius (type strain LMG 20536T; EMBL accession no. AJ316171; G + C content of the type strain 46·0 mol%), Vibrio brasiliensis (type strain LMG 20546T; EMBL accession no. AJ316172; G + C content of the type strain 45·9 mol%) and Vibrio xuii (type strain LMG 21346T; EMBL accession no. AJ316181; G + C content of the type strain 46·6 mol%). These species can be differentiated on the basis of phenotypic features, including fatty acid composition (particularly 14 : 0 iso, 14 : 0 iso 3-OH, 16 : 0 iso, 16 : 0, 17 : 0 and 17 : 1?8c), enzyme activities and utilization and fermentation of various carbon sources

    Numerical and experimental investigations of three-dimensional container filling with Newtonian viscous fluids

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    This work employs numerical and experimental approaches to investigate three-dimensional container filling with Newtonian viscous fluids. For this purpose, a computer code developed for simulating three-dimensional free surface flows has been used. The CFD Freeflow3D code was specifically designed to deal with unsteady three-dimensional flows possessing multiple moving free surfaces. An experimental apparatus that allows the visualization of the various phenomena that can occur during the filling of containers has been constructed and employed. Experiments on container filling were carried out by varying the fluid velocity at the injection nozzle. This paper presents a computational study on container filling with Newtonian viscous fluids and employs the experimental results to validate the software. The experimental observations were compared with the predictions from the Freeflow3D code and good agreement between the two sets of results is observed. Moreover, the code predictions showed that it is capable of capturing the most relevant phenomena observed in the experiments.The Brazilian authors would like to acknowledge the financial support given by the funding agencies: CNPq - Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (Grant Nos. 302631/2010-0, 301408/2009-2, 472514/2011-3), FAPESP - Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (Grant No. 2011/13930-0) and CAPES Grant Nos. BEX 2844/10-9 and 226/09 (CAPES-FCT). This work is part of the activities developed within the CEPID-CeMEAI FAPESP project Grant No. 2013/07375 - 0 and also benefits from the early collaboration within the framework of the University of Sao Paulo (Brazil) and University of Porto (Portugal) research agreements. The Portuguese authors gratefully acknowledge funding from Fundacao para a Ciencia e Tecnologia (FCT) under the project PEst-C/CTM/LA0025/2013 (Strategic Project - LA 25-2013-2014), project PTDC/MAT/121185/2010 and FEDER, via FCT

    High-Speed Cylindrical Collapse of Two Perfect Fluids

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    In this paper, the study of the gravitational collapse of cylindrically distributed two perfect fluid system has been carried out. It is assumed that the collapsing speeds of the two fluids are very large. We explore this condition by using the high-speed approximation scheme. There arise two cases, i.e., bounded and vanishing of the ratios of the pressures with densities of two fluids given by cs,dsc_s, d_s. It is shown that the high-speed approximation scheme breaks down by non-zero pressures p1,p2p_1, p_2 when cs,dsc_s, d_s are bounded below by some positive constants. The failure of the high-speed approximation scheme at some particular time of the gravitational collapse suggests the uncertainity on the evolution at and after this time. In the bounded case, the naked singularity formation seems to be impossible for the cylindrical two perfect fluids. For the vanishing case, if a linear equation of state is used, the high-speed collapse does not break down by the effects of the pressures and consequently a naked singularity forms. This work provides the generalisation of the results already given by Nakao and Morisawa [1] for the perfect fluid.Comment: 11 pages, 1 figure, accepted for publication in Gen. Rel. Gra

    Generation and validation of genetic markers for the selection of carioca dry bean genotypes with the slow-darkening seed coat trait

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    Slow darkening (SD) is a trait that helps to maintain a brighter seed coat appearance in certain market classes of dry beans. The aim of this study was to generate new fluorescence-based markers and validate previously identified microsatellite markers for linkage to the SD trait in lines of the carioca market class. Four segregating populations were generated by Embrapa, the Brazilian Agricultural Research Corporation, from crosses between the SD cultivar BRSMG Madrepe´rola and the regular-darkening cultivars BRS Estilo, BRS Cometa, BRS Nota´vel and BRS Sublime. These populations were screened with the simple-sequence markers Pvsd- 1158 and PVM02TC116 and with a TaqManTM marker designed for the single-nucleotide polymorphism (SNP) PvbHLHp12804. A KASP marker was also designed for the PvbHLHp12804 marker for testing on advanced carioca lines developed by the University of Saskatchewan. In the carioca lines developed by Embrapa, PVM02TC116 proved unsuitable for marker-assisted selection (MAS). Both the Pvsd-1158 and PvbHLHp12804 markers were found to be tightly linked to the gene responsible for the SD trait, with genetic distances calculated at 2.8 cM for Pvsd-1158 and 2.0 and 3.1 cM for PvbbHLHp12804, respectively. These markers presented more than 97% of selection efficiency. The genotypic scoring using the PvbHLHp12804 KASP marker was perfectly correlated with the phenotype in all lines of the University of Saskatchewan. The results of this study validates the use of Pvsd-1158 as a gel-based marker for SD in carioca beans. The new fluorescence-based SNP PvbHLHp12804 markers exhibited very tight linkage to SD in carioca and pinto bean lines. These markers will be ideal for MAS for the SD trait in these market classes
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