566 research outputs found

    Water and Irrigation Management in Arid and Semiarid Zones

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    As we wrote in the summary of this special issue, the purpose of this Special Issue is to report, in more detail, research of water resources management in the frame of sustainable development [...

    Double-electron ionization driven by inhomogeneous fields

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    Authors may self-archive the author’s accepted manuscript of their articles on their own websites. Authors may also deposit this version of the article in any repository, provided it is only made publicly available 12 months after official publication or later. He/ she may not use the publisher's version (the final article), which is posted on SpringerLink and other Springer websites, for the purpose of self-archiving or deposit. Furthermore, the author may only post his/her version provided acknowledgement is given to the original source of publication and a link is inserted to the published article on Springer's website. The link must be provided by inserting the DOI number of the article in the following sentence: “The final publication is available at Springer via https://link.springer.com/article/10.1007/s00340-017-6672-4"Electron–electron correlation effects play a crucial role in our understanding of sequential (SDI) and non-sequential double ionization (NSDI) mechanisms. Here, we present a theoretical study of NSDI driven by plasmonic-enhanced spatial inhomogeneous fields. By numerically solving the time-dependent Schrödinger equation for a linear reduced model of He and a double-electron time-evolution probability analysis, we provide evidence for enhancement effects in NSDI showing that the double ionization yield at lower laser peak intensities is increased due to the spatial inhomogeneous character of plasmonic-enhanced field. The change in the emission direction of the double-ion as a function of the field inhomogeneity degree demonstrates that plasmonic-enhanced fields could configure a reliable instrument to control the ion emission. Furthermore, our quantum mechanical model, as well as classical trajectory Monte Carlo simulations, show that inhomogeneous fields are as well as a useful tool for splitting the binary and recoil processes in the rescattering scenario.This work was supported by the project ELI-Extreme Light Infrastructure-phase 2 (Project No. CZ.02.1.01/0.0/0.0/ 15_008/0000162) from European Regional Development Fund, Spanish MINECO (National Plan grants FIS2011-30465-C02-01, FOQUS No. FIS2013-46768-P, FISICATEAMO FIS2016-79508-P and Severo Ochoa Excellence Grant No. SEV-2015-0522), the Generalitat de Catalunya (SGR 874 and CERCA/Program) and Fundació Privada Cellex Barcelona. N.S. was supported by the Erasmus Mundus Doctorate Program Europhotonics (Grant No. 159224-1-2009-1-FR-ERA MUNDUS-EMJD). N.S., A.C., and M.L. acknowledge ERC AdG OSYRIS, EU FETPRO QUIC and National Science Centre, Poland—Symfonia Grant 2016/20/W/ST4/00314. A. S. L. acknowledges Max Planck Center for Attosecond Science (MPC-AS). J. A. P.-H. acknowledges to the Spanish Ministerio de Economía y Competitivi- dad (FURIAM Project No. FIS2013-47741-R and PALMA project FIS2016- 81056-R) and Laserlab-Europe (EU-H2020 654148). L.O. acknowledges valuable input from Andre Staudte. The authors thankfully acknowledge the computer resources at MareNostrum, technical expertise and assistance provided by the Barcelona Supercomputing Center and the Red Española de Supercomputación (RES)Peer ReviewedPostprint (author's final draft

    Are we there yet?: Advances in anytime-valid methods for hypothesis testing and prediction

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    Statistical considerations guide the design and implementation of the experiments that scientists perform. For instance, in a clinical trial about a the efficacy of a treatment, its effect in a certain minimum amount of patients has to be observed in order to make confident assertions about the efficacy of the treatment in the general population---observing one or two patients is, as an extreme example, not enough. Sound statistical methods are required to assess the quality of these general assertions. Currently, the most flexible methods allow experimentalists to analyze the data that they gather as it is collected, and to make decisions about gathering more data, stopping an experiment or starting new one based on their findings. In short, they allow experimentalists to ask "are we there yet?" as their experiments are ongoing. This is crucial in applications such as monitoring of clinical trials, online experimentation and quality control in engineering. The statistical methods that make this degree of flexibility possible are called, in the statistical community, anytime valid; they are the main focus of this dissertation. In this work, a number of mathematical results about optimal anytime-valid methods are shown. Group-invariant models, the analysis of time-to-event data, and prediction with expert advice are investigated.Number theory, Algebra and Geometr

    La práctica de riegos ancestrales andinos: el riego por Kanis

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    El riego es una técnica agrícola ancestral desarrollada por las culturas tradicionales andinas, en armonía con las características ambientales y productivas de la zona. La práctica de riego tuvo que ser adaptada a las grandes pendientes dando lugar a técnicas muy particulares que aún hoy día se practican. Los valles interandinos del Departamento de La Paz, Bolivia, es un lugar privilegiado para el estudio de sistemas de riego tradicionales. El trabajo experimental se llevó a cabo en la comunidad de Jatichulaya, localizada en el pueblo de Charazani, Bolivia, a una altitud de 3250 msnm con una precipitación anual media de 450 mm. El sistema de riego tradicional en ella practicado es el llamado riego por kanis. La palabra kanis es un vocablo quechua que hace alusión a la apertura de surcos para la conducción del agua. El sistema de riego no causa erosión del suelo ya que el manejo del agua se hace siguiendo las curvas de nivel. Sin embargo, las necesidades de mano de obra son muy elevadas. La persona a cargo de la distribución del agua y de su entrega a los regantes es el llamado Agente de Aguas.Irrigation is an ancient agricultural technique developed by the Andean traditional cultures in harmony with environmental and productive characteristics of the area. Irrigation practice had to be adapted to the steep slopes leading to very specific techniques that are practiced even today In Bolivia, the interandean valleys of La Paz’s Department are privileged places for the study of traditional irrigation systems. The experimental work was carried out in the peasant community of Jatichulaya, located in Charazani, at an altitude of 3,250 meters above sea level, with an average annual rainfall of about 450 mm. The traditional irrigation system practiced there is called the kanis’s method. The word kanis is a quechua word that refers to furrow irrigation opening for water conveyance. This irrigation system avoids soil erosion because it follows contour lines. Thereby, soil is protected but manpower required in the irrigation practice was excessive. The person in charge of water distribution and delivery to irrigators is called Agente de Aguas (Water’s officer)

    NDT for the detection and characterization of superficial treatments on stone material from archaeological sites of Merida (Spain)

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    Different treatments (consolidation and water-repellent) were applied on samples of marble and granite from the Front stage of the Roman Theatre of Merida (Spain). The main goal is to study the effects of these treatments on archaeological stone material, by analyzing the surface changes. X-Ray Fluorescence and Laser-Induced Breakdown Spectroscopy techniques, as well as Nuclear Magnetic Resonance have been used in order to study changes in the surface properties of the material, comparing treated and untreated specimens. The results confirm that silicon (Si) marker tracking allows the detection of applied treatments, increasing the peak signal in treated specimens. Furthermore, it is also possible to prove changes both within the pore system of the materialand in the distribution of surface water, resulting from the application of these product

    Environment Control with Low-Cost Microcontrollers and Microprocessors: Application for GreenWalls

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    Green wall irrigation procedures are a particularly important and hard task, given that the quality of the green wall depends on them. There is currently a wide variety of irrigation programmers available, with a range of functions and prices, thereby replacing manual activities and making it easier to maintain green walls. This paper proposes the use of low-cost automated irrigation programmers via a freeware called Arduino. The system is based on air and substrate measurements to ensure optimal plant growth and high water-use efficiency. At certain thresholds, the irrigation system is activated. This not only makes irrigation more convenient but also helps to reduce energy consumption, increases irrigation efficiency and saves time. The data is then sent via Transmission Control Protocol using Internet of Things technology, in this case ThingSpeak. The platform compiles the data and presents them in simple graphical format, thus enabling real-time monitoring from wherever there is Internet access. Together with Arduino, the project incorporates the Raspberry pi system that operates like a database via Hypertext Transfer Protocol Wi-Fi received by a Structured Query Language (MySQL) server using Hypertext Preprocessor. These data are used for the subsequent analysis of green wall performance

    Stand dynamics, spatial pattern and site quality in Austrocedrus chilensis forests in Patagonia, Argentina

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    Aim of study: The objective of this study was to analyze the stand structure and spatial pattern of two A. chilensis stands with contrasting soil conditions and different site qualities in order to explore if these differences lead to patterns similar to the ones observed under different precipitation conditions.Area of study: The study was carried out in two stands located near the city of El Bolsón (41° 56’S - 71° 33’ W), Rio Negro, Argentina.Material and Methods: We evaluated age difference between canopy strata (upper and lower) in two stands with different site qualities by means of a Mann-Whitney test. Dead individuals by diameter class were compared by means of a chi square test. Spatial distribution pattern was analyzed using the pair-correlation function and the mark-correlation function.Main results: Both sites exhibited a random spatial distribution of A. chilensis but different processes seem to underlie the patterns. In the low-quality site facilitation and continuous establishment led to a transient clumped spatial pattern. Mortality mediated by competition occurred mainly on small trees resulting in the current random pattern. On the other hand, spatial pattern in the high-quality site does not reflect a facilitation mediated recruitment. The upper strata established synchronously and subsequent regeneration was episodic.Research highlights: The results show that the differences in site quality may lead to different establishment spatial patterns, showing the importance of facilitation processes in sites with drier soil conditions and lower quality, although results may be site specific, due to the lack of replications.Keywords: Spatial analysis; regeneration; mortality; competition; facilitation.Abbreviations used:  LQ: low-quality site; HQ: high-quality site

    Local Anomalies, Local Equivariant Cohomology and the Variational Bicomplex

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    The locality conditions for the vanishing of local anomalies in field theory are shown to admit a geometrical interpretation in terms of local equivariant cohomology, thus providing a method to deal with the problem of locality in the geometrical approaches to the study of local anomalies based on the Atiyah-Singer index theorem. The local cohomology is shown to be related to the cohomology of jet bundles by means of the variational bicomplex theory. Using these results and the techniques for the computation of the cohomology of invariant variational bicomplexes in terms of relative Gel'fand-Fuks cohomology introduced in [6], we obtain necessary and sufficient conditions for the cancellation of local gravitational and mixed anomalies.Comment: 36 pages. The paper is divided in two part

    Distribution Uniformity in Intensive Horticultural Systems of Almería and Influence of the Production System and Water Quality

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    The high productivity and efficiency of the use of irrigation water that characterizes greenhouse horticultural crops can be affected by poor irrigation distribution uniformity. The objective of this work was to estimate the average irrigation distribution uniformity (DU) of the greenhouses in Almería, determining the influence of the irrigation water quality as well as the production system on this uniformity. A prospective study was carried out in which commercial farms were selected that used different water qualities (groundwater vs. reclaimed) with different production systems (organic vs. conventional/integrated). The average irrigation distribution uniformity in the greenhouses of Almería was 80%. The farms with organic production systems presented a drastic DU reduction with respect to conventional farms (48% vs. 88%). The DU of the irrigation water presented in commercial farms irrigated with reclaimed water presented a lower DU than those irrigated with groundwater (76% vs. 86%). The distribution of irrigation depth of water in the greenhouses showed slight variations (from 3.2 to 2.9 mm) depending on the emitter position, with the highest values being at the head of the sub-main pipe and dripper line and the lowest at the end of the sub-main pipe and dripper line. The depth of water values was very close to the theoretical average of 3 mm. Water quality affects the distribution pattern of the depth of water in greenhouses. Installations irrigated with reclaimed water showed greater oscillation of the water depth within the sub-unit, varying from 3.6 to 2.0 mm, although the average depth was located close to the theoretical depth (3 mm). The production system affected the distribution of the depth of water—in the organic system, the depth underwent greater variation depending on the position of the emitter in the sub-unit, ranging from 1.7 to 3.3 mm. In addition, within this production system, the median depth of water was close to 2.5 mm, lower than the theoretical depth (3 mm), which denoted a certain generalized filling that was accentuated at the end of the dripper line and sub-main pipe
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