306 research outputs found
Comportamiento de 13 modelos de cinta de riego en condiciones de invernadero con agua regenerada
El objetivo de este trabajo ha sido seleccionar modelos de cinta de riego con una mejor adaptación a las condiciones de invernadero y riego con aguas regeneradas. Se ha evaluado el comportamiento de 13 modelos comerciales de cintas de riego seleccionados de entre los más utilizados en los cultivos hortícolas al aire libre, y aquellos que, las empresas instaladoras y fabricantes consideren que, por sus características, pueden tener un buen comportamiento con este tipo de aguas. En la evaluación de campo todos los emisores han presentado valores de uniformidad elevados al comienzo de la campaña de riego. Cinco de las cintas se clasifican como excelentes y el resto como buenas. Al finalizar las 114 horas de trabajo decae sustancialmente la uniformidad. El comportamiento tras la finalización de la primera campaña de riego se puede considerar equiparable al obtenido en un estudio previo con una selección de 20 emisores en ramal convencional y este tipo de aguas. Se puede concluir que las cintas de riego localizado pueden ser una alternativa a los ramales de riego convencionales cuando se riega con aguas residuales urbanas regeneradas, siempre que se elija un material de una mínima calidad y el ratio de sustitución garantice una uniformidad alta
Prediction and evaluation of biomass obtained from citrus trees pruning
[EN] The aim of this work was to evaluate the amount of residual biomass obtained from citrus tree plantations. This amount is influenced by the variety and aim of the pruning. The trials show that the amount of pruned biomass can be considered similar in the varieties Naveline and Washington Navel, giving an average 4.73 kg per tree and 2.68 tons per hectare. The Valencia Late produced about 48% more than the other evaluated varieties. The amount of residual biomass per tree obtained in formation pruning was about 49% lower than the trees in full production, giving 4.7 tons of dry biomass per hectare. Furthermore, the amount of pruned biomass from mandarin varieties studied show that they can be classified two groups. Varieties Clemenvilla and Owall form the first homogeneous group with bigger amount of residues with average 9.6 kg per tree and 6.9 tons per hectare, while the second homogeneous group included by the rest of varieties, with 3.8 kg per tree and 2.9 tons per hectare. Factors, such as age or growing space per tree increase the wood residues production to 66% and 53.3%, respectively, in mandarin trees. Regression equations have been modeled to predict the available biomass per tree and per hectare from dendrometic characteristics of the trees. The coefficients of determination have been acceptable. The drying process of pruned materials has been depicted. The density and gross power heat have been measured. The information offered by these equations is of vital importance to estimate the amount of biomass that is generated in a given area, and for implementing GIS maps. In addition, logistic algorithms can be applied.The techniques shown in this paper were developed by the project AGL2007-62328 funded by the Ministry of Education and Science of Spain, and FEDER fundsVelázquez Martí, B.; Fernández González, E.; López Cortés, I.; Callejón-Ferre, A. (2013). Prediction and evaluation of biomass obtained from citrus trees pruning. Journal of Food Agriculture and Environment. 11(3&4):1485-1494. http://hdl.handle.net/10251/6295814851494113&
Evaluation of Chromane Derivatives: Promising Privileged Scaffolds for Lead Discovery within Alzheimer’s Disease
The chromane ring system is widely distributed in nature and has proven to be a highly potent pharmacophore in medicinal chemistry, which includes the area of Alzheimer’s and Parkinson’s diseases. We report on the development of a gem-dimethylchroman-4-ol family that was shown to give good inhibition of equine serum butyrylcholinesterase (eqBuChE) (in the range 2.9 – 7.3 μM) and in the same range of currently used drugs. We also synthesized a small library of gem-dimethylchroman-4-amine compounds, via a simple reductive amination of the corresponding chromanone precursor, that were also selective for eqBuChE presenting inhibitions in the range 7.6 – 67 μM. Kinetic studies revealed that they were mixed inhibitors. Insights into their mechanism of action were obtained through molecular docking and STD-NMR experiments, and the most active examples showed excellent drug-likeness and pharmacological properties predicted using Swiss-ADME. We also prepared a set of propargyl gem-dimethylchromanamines, for monoamine oxidase (MAO) inhibition but they were only moderately active (the best being 28% inhibition at 1 µM on MAO-B). Overall, our compounds were found to be best suited as inhibitors for BuChE
High valence transition metal doped strontium ferrites for electrode materials in symmetrical SOFCs
AbstractIn this paper we report the successful incorporation of high valence transition metals, i.e. Cr, Mo, W, V, Nb, Ti, Zr into SrFeO3−δ perovskite materials, for potential applications as symmetric electrode materials for Solid Oxide Fuel Cells. It is observed that the doping leads to a change from an orthorhombic structure (with partial ordering of oxygen vacancies) to a cubic one (with the oxygen vacancies disordered). These electrodes are chemically compatibles with Ce0.9Gd0.1O1.95 (CGO) and La0.8Sr0.2Ga0.8Mg0.2O3−δ (LSGM) electrolytes at least up to 1100 °C. Thermal annealing experiments in 5% H2–Ar at 800 °C also show the stability of the doped samples in reducing conditions, suggesting that they may be suitable for both cathode and anode applications. In contrast, reduction of undoped SrFeO3−δ leads to the observation of extra peaks indicating the formation of the brownmillerite structure with the associated oxygen vacancy ordering. The performance of these electrodes was examined on dense electrolyte pellets of CGO and LSGM in air and 5% H2–Ar. In both atmospheres an improvement in the area specific resistances (ASR) values is observed for the doped samples with respect to the parent compound. Thus, the results show that high valence transition metals can be incorporated into SrFeO3−δ-based materials and can have a beneficial effect on the electrochemical performance, making them potentially suitable for use as cathode and anode materials in symmetrical SOFC
Tracking pan-continental trends in environmental contamination using sentinel raptors — what types of samples should we use?
Biomonitoring using birds of prey as sentinel species has been mooted as a way to evaluate the success of European Union directives that are designed to protect people and the environment across Europe from industrial contaminants and pesticides. No such pan-European evaluation currently exists. Coordination of such large scale monitoring would require harmonisation across multiple countries of the types of samples collected and analysed-matrices vary in the ease with which they can be collected and the information they provide. We report the first ever pan-European assessment of which raptor samples are collected across Europe and review their suitability for biomonitoring. Currently, some 182 monitoring programmes across 33 European countries collect a variety of raptor samples, and we discuss the relative merits of each for monitoring current priority and emerging compounds. Of the matrices collected, blood and liver are used most extensively for quantifying trends in recent and longer-term contaminant exposure, respectively. These matrices are potentially the most effective for pan-European biomonitoring but are not so widely and frequently collected as others. We found that failed eggs and feathers are the most widely collected samples. Because of this ubiquity, they may provide the best opportunities for widescale biomonitoring, although neither is suitable for all compounds. We advocate piloting pan-European monitoring of selected priority compounds using these matrices and developing read-across approaches to accommodate any effects that trophic pathway and species differences in accumulation may have on our ability to track environmental trends in contaminants
Spatial evolution of an AMD stream in the Iberian Pyrite Belt: process characterization and control factors on the hydrochemistry
This paper presents hydrochemical data of an AMD stream in the Iberian Pyrite Belt, obtained from its source, in the Poderosa Mine Portal, till its confluence at the Odiel River. The main objective is to establish potential interdependent relations between sulfate and metals’ loads and the following physical-chemical variables: pH, electric conductivity (EC), redox potential (EH), and dissolved oxygen (O2). All the parameters show a global increasing tendency since the tunnel’s exit to the confluence at Odiel River. The TDS and EC are two relevant exceptions. They behave similarly, showing a decreasing trend and a strong inflection that describes a minimum immediately after the discharging point. The spatial analysis combined with statistical tools put in evidence the typical AMD processes and the respective physical-chemical implications. Inputs with distinctive hydrochemical signatures impose relevant modifications in the Poderosa creek waters. This indicates low hydrochemical inertia and high vulnerability to external stimulus.Financial support for this research was provided by DGCICYT National Plan, project CGL2010-21268-C02-01 and the Andalusian Autonomous Government Excellence Projects, Project RNM-6570
I. MUFFIT: A multi-filter fitting code for stellar population diagnostics
Numerical methods and codes.-- et al.[Aims]: We present MUFFIT, a new generic code optimized to retrieve the main stellar population parameters of galaxies in photometric multi-filter surveys, and check its reliability and feasibility with real galaxy data from the ALHAMBRA survey. [Methods]: Making use of an error-weighted X2-test, we compare the multi-filter fluxes of galaxies with the synthetic photometry of mixtures of two single stellar populations at different redshifts and extinctions, to provide the most likely range of stellar population parameters (mainly ages and metallicities), extinctions, redshifts, and stellar masses. To improve the diagnostic reliability, MUFFIT identifies and removes from the analysis those bands that are significantly affected by emission lines. The final parameters and their uncertainties are derived by a Monte Carlo method, using the individual photometric uncertainties in each band. Finally, we discuss the accuracies, degeneracies, and reliability of MUFFIT using both simulated and real galaxies from ALHAMBRA, comparing with results from the literature. [Results]: MUFFIT is a precise and reliable code to derive stellar population parameters of galaxies in ALHAMBRA. Using the results from photometric-redshift codes as input, MUFFIT improves the photometric-redshift accuracy by ∼10-20%. MUFFIT also detects nebular emissions in galaxies, providing physical information about their strengths. The stellar masses derived from MUFFIT show excellent agreement with the COSMOS and SDSS values. In addition, the retrieved age-metallicity locus for a sample of z ≤ 0.22 early-type galaxies in ALHAMBRA at different stellar mass bins are in very good agreement with the ones from SDSS spectroscopic diagnostics. Moreover, a one-to-one comparison between the redshifts, ages, metallicities, and stellar masses derived spectroscopically for SDSS and by MUFFIT for ALHAMBRA reveals good qualitative agreements in all the parameters, hence reinforcing the strengths of multi-filter galaxy data and optimized analysis techniques, like MUFFIT, to conduct reliable stellar population studies.L.A.D.G. acknowledges support from the "Caja Rural de Teruel" for developing this research. A.J.C. is a Ramon y Cajal Fellow of the Spanish Ministry of Science and Innovation. This work has been supported by the "Programa Nacional de Astronomia y Astrofisica" of the Spanish Ministry of Economy and Competitiveness (MINECO) under grant AYA2012-30789, as well as by FEDER funds and the Government of Aragon, through the Research Group E103. L.A.D.G. also thanks the Mullard Space Science Laboratory (MSSL) and Royal Astronomical Society (RAS) for offering the opportunity to support and develop part of this research in collaboration with I.F. MINECO grants AYA2010-15081, AYA2010-15169, AYA2010-22111-C03-01, AYA2010-22111-C03-02, AYA2011-29517-C03-01, AYA2013-40611-P, AYA2013-42227-P, AYA2013-43188-P, AYA2013-48623-C2-1, AYA2013-48623-C2-2, and AYA2014-58861-C3-1 are also acknowledged, together with Generalitat Valenciana projects Prometeo 2009/064 and PROMETEOII/2014/060, and Junta de Andalucia grants TIC114, JA2828, and P10-FQM-6444. MP acknowledges financial support from the JAE-Doc programme of the Spanish National Research Council (CSIC), co-funded by the European Social Fund.Peer Reviewe
The ALHAMBRA survey: Bayesian photometric redshifts with 23 bands for 3 deg2
A. Molino et al.The Advance Large Homogeneous Area Medium-Band Redshift Astronomical (ALHAMBRA) survey has observed eight different regions of the sky, including sections of the Cosmic Evolution Survey (COSMOS), DEEP2, European Large-Area Infrared Space Observatory Survey (ELAIS), Great Observatories Origins Deep Survey North (GOODS-N), Sloan Digital Sky Survey (SDSS) and Groth fields using a new photometric system with 20 optical, contiguous ~300-Å filters plus the JHKs bands. The filter system is designed to optimize the effective photometric redshift depth of the survey, while having enough wavelength resolution for the identification of faint emission lines. The observations, carried out with the Calar Alto 3.5-m telescope using the wide-field optical camera Large Area Imager for Calar Alto (LAICA) and the near-infrared (NIR) instrument Omega-2000, represent a total of ~700 h of on-target science images. Here we present multicolour point-spread function (PSF) corrected photometry and photometric redshifts for ~438 000 galaxies, detected in synthetic F814W images. The catalogues are complete down to a magnitude I~24.5AB and cover an effective area of 2.79 deg2. Photometric zero-points were calibrated using stellar transformation equations and refined internally, using a new technique based on the highly robust photometric redshifts measured for emission-line galaxies. We calculate Bayesian photometric redshifts with the Bayesian Photometric Redshift (BPZ)2.0 code, obtaining a precision of δz/(1+zs)=1 per cent for I<22.5 and δz/(1+zs)=1.4 per cent for 22.5<I<24.5. The global n(z) distribution shows a mean redshift 〈z〉=0.56 for I<22.5 AB and 〈z〉=0.86 for I<24.5 AB. Given its depth and small cosmic variance, ALHAMBRA is a unique data set for galaxy evolution studies. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.We acknowledge financial support from the Spanish MICINN under the Consolider-Ingenio 2010 Program grant CSD2006-00070: First Science with the GTC. Part of this work was supported by Junta de Andalucía, through grant TIC-114 and the Excellence Project P08-TIC-3531, and by the Spanish Ministry for Science and Innovation through grants AYA2006-1456, AYA2010-15169, AYA2010-22111-C03-02, AYA2010-22111-C03-01 and Generalitat Valenciana project Prometeo 2009/064.Peer Reviewe
A Model for the Development of the Rhizobial and Arbuscular Mycorrhizal Symbioses in Legumes and Its Use to Understand the Roles of Ethylene in the Establishment of these two Symbioses
We propose a model depicting the development of nodulation and arbuscular mycorrhizae. Both processes are dissected into many steps, using Pisum sativum L. nodulation mutants as a guideline. For nodulation, we distinguish two main developmental programs, one epidermal and one cortical. Whereas Nod factors alone affect the cortical program, bacteria are required to trigger the epidermal events. We propose that the two programs of the rhizobial symbiosis evolved separately and that, over time, they came to function together. The distinction between these two programs does not exist for arbuscular mycorrhizae development despite events occurring in both root tissues. Mutations that affect both symbioses are restricted to the epidermal program. We propose here sites of action and potential roles for ethylene during the formation of the two symbioses with a specific hypothesis for nodule organogenesis. Assuming the epidermis does not make ethylene, the microsymbionts probably first encounter a regulatory level of ethylene at the epidermis–outermost cortical cell layer interface. Depending on the hormone concentrations there, infection will either progress or be blocked. In the former case, ethylene affects the cortex cytoskeleton, allowing reorganization that facilitates infection; in the latter case, ethylene acts on several enzymes that interfere with infection thread growth, causing it to abort. Throughout this review, the difficulty of generalizing the roles of ethylene is emphasized and numerous examples are given to demonstrate the diversity that exists in plants
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