124 research outputs found

    El estado actual de la investigación sobre la congruencia persona-ambiente. Propuesta de aplicación de un diseño experimental

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    En el presente trabajo se hace una revisión del estado actual de la investigación sobre la congruencia persona-ambiente, analizando los principales problemas conceptuales y metodológicos que existen en esta línea de investigación, así como las críticas que recibe uno de los modelos más representativos del momento: el modelo de la elección vocacional de Holland. Según este autor, los individuos suelen elegir profesiones que son congruentes con sus características personales, y este ajuste tiene repercusiones positivas tanto para el rendimiento como para la satisfacción en el trabajo. Además, existen otros modelos que han sido propuestos desde diferentes perspectivas (el estrés laboral, socialización laboral, ajuste laboral...). Teniendo en cuenta los inconvenientes que presentan la mayoría de los estudios empíricos realizados, se plantea la posibilidad de abordar el tema desde el paradigma experimental sugiriendo un diseño que permite solventar, o al menos minimizar, dichos problemas.The aim of this paper is to review the present state of the person-environment congruence research. We analyze the main conceptual and methodological problems that this research have and the cristicisms that one of the most representative model receives: Holland’s vocational choices model. This author suggests that the individuals tend to choose occupations that are congruent with their personal characteristics, and that this fi t (or adjustment) has positive implications both for the performance and job satisfaction. On the other hand, models from other approaches have also been proposed (work stress, work socialization, laboral fi t (or adjustment...). Taking into account the inconvenients that most of these kind of studies have, the possibility of start on this subject from an experimental paradigm suggesting a design that may solve or reduce these problems is proposed

    Evaluation of the Inclusion of the Green Seaweed Ulva ohnoi as an Ingredient in Feeds for Gilthead Sea Bream (Sparus aurata) and European Sea Bass (Dicentrarchus labrax)

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    Simple Summary The use of seaweeds in aquafeeds is receiving increasing attention due to their potential nutritional and functional benefits. However, several green seaweeds such as Ulva presents nutritional limitations because of the undigestible polysaccharides, although these may exert a positive effect on the immunological status of the fish. The present study developed three different experiments aimed to re-evaluate the presence of protease inhibitors described for Ulva ohnoi, to assess its nutritional value as an ingredient and also to evaluate its potential protective effect on the oxidative metabolism of fish, being experiments developed in two different fish species (European sea bass Dicentrarchus labrax and gilthead sea bream, Sparus aurata). Results indicate the absence of negative effects of U. ohnoi on protein digestion of sea bream but a limited value as a feed ingredient. In contrast, its contents in bioactives seem to be correlated to the observed positive effects on the immune status and oxidative metabolism when fish are challenged by the consumption of highly oxidized dietary oil. This study evaluated the use of Ulva ohnoi as an ingredient in feeds for aquaculture in three different experiments. Experiment 1 was oriented to confirm the negative effect of U. ohnoi on fish digestion. Experiment 2 assessed the effect on growth, feed efficiency, and immune status of juvenile sea bass (Dicentrarchus labrax) fed on diets including U. ohnoi, previously treated or not with carbohydrases used to partially hydrolyze indigestible polysaccharides. Experiment 3 was aimed to evaluate the potential protective effect of U. ohnoi on the oxidative status of sea bream (Sparus aurata) challenged by the consumption of a feed formulated with the oil fraction completely oxidized. Results show a negligible effect of U. ohnoi meal on protein digestion when included in feeds at levels of 10% or less. Moreover, results of growth and feed use evidenced the possibility of using up to 5% inclusion of algal meal in feeds without adverse effects on the zootechnical parameters, while the enzyme pretreatment was ineffective to improve its nutritional use. Finally, the inclusion of U. onhoi in feeds determined both an immunostimulatory effect, evidenced by an increase in skin mucus lysozyme in the two mentioned fish species, and a positive influence on the oxidative metabolism of seabream when fed on a diet including rancid oil.This research was funded by the Excellence Campus of Marine Science (CEIMAR) within the "III Call for Innovative Projects in the field of Blue Economy"

    Milk production and adjustment of lactation curve in the Florida caprine breed

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    Milk yield and average lactation curves is studied in the Florida caprine breed. 968 valid lactations are analyzed corresponding to 317 females kept under a semi-extensive management system, fed by grazing and additional in the feeding rack, with an average feed intake of 1783 g/day of dry matter in autumn-winter, 2938 g/day in spring and 1974 g/day in summer. The milking was done in the morning, and the milk control monthly. Milk production was determined with the adaptation of Carré to the Fleischmann method. A 71.6 percent of the lactations have a duration that fluctuates between 188 and 341 days, being the average duration 301.5 ± 3 days. The lactations that initiate in winter-spring are of shorter than the ones of summer-autumn (288.4±3.6 days vs 315.5±5.2 days), the same as the first lactation in comparison to the rest (283.7±4.8 days vs 310.5±3.8 days). The type of kidding doesn"t affect significantly the duration of the lactation. The milk yield to 210, 240, 270 days and complete lactation is 475.3±4.3 kg, 538.9±5.0 kg, 598.5±6.3 kg and 611.4±7.8 kg, respectively. The females that kid in winter-spring produce more quantity of milk until 270 days of lactation, although their production is less at complete lactation due to its shorter duration. The primiparous goats produce a 19-20 percent less quantity of milk than the multiparous goats, while the ones that kid more than one kid produce a 38-40 percent more than the ones having a simple kid or abortions. The Inverse polynomial and Incomplete gamma functions present a similar adjustment (R2= 0.943; CME=0.5361 and 0.5365), although they show differences in the components of the lactation curve: the initial production is estimated in 0.82 kg/d and 2.56 kg/d; maximum production in 2.71 kg/d and 2.68 kg/d; the peak production at day 27 and 13, and the decrese in 4.58 g/d and 4.32 g/d, respectively.Se estudia la producción láctea y la curva de lactación en caprinos de raza Florida. Se analizan 968 lactaciones válidas correspondientes a 317 hembras manejadas en un régimen semiextensivo, alimentadas a pasto más suplementación en pesebre, con un nivel de ingesta medio de 1783 g/día de materia seca en otoño-invierno, 2938 g/día en primavera y 1974 g/día en verano. El ordeño se efectuaba por la mañana, y el control lechero se realizaba mensualmente. La producción de leche se determinó con la adaptación de Carré al método de Fleishmann. El 71,6 p.100 de las lactaciones tienen una duración comprendida entre 188 y 341 días, siendo la duración media de 301,5±3 días. Las lactaciones que se inician en invierno-primavera son más cortas que las de verano-otoño (288,4±3,6 días vs 315,5±5,2 días), al igual que la primera lactación frente a las restantes (283,7±4,8 días vs 310,5±3,8 días). El tipo de parto no afecta significativamente la duración de la lactación. La producción de leche tipificada a 210, 240 y 270 días y a lactación completa es de 475,3±4,3 kg, 538,9±5,0 kg, 598,5±6,3 kg y 611,4±7,8 kg, respectivamente. Las hembras que paren en invierno- primavera producen mayor cantidad de leche hasta 270 días de lactación, en tanto que su producción es menor a lactación completa por su menor duración. Las cabras primíparas producen un 19-20 p.100 menos cantidad de leche que las multíparas, mientras que las que paren más de un cabrito producen un 38-40 p.100 más que las de parto simple o abortos. Las funciones Polinomial inversa y Gamma incompleta presentan un ajuste similar (R2= 0,943; C.M.E= 0,5361 y 0,5365), aunque muestran diferencias en las componentes de la curva de lactación: la producción inicial se estima en 0,82 kg/d y 2,56 kg/d, la producción máxima en 2,71 kg/d y 2,68 kg/d, el pico de lactación al día 27 y 13, y el descenso en 4,58 g/d y 4,32 g/d, respectivamente

    Instructional Changes Adopted for an Engineering Course: Cluster Analysis on Academic Failure

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    As first-year students come from diverse backgrounds, basic skills should be accessible to everyone as soon as possible. Transferring such skills to these students is challenging, especially in highly technical courses. Ensuring that essential knowledge is acquired quickly promotes the student’s self-esteem and may positively influence failure rates. Metaphors can help do this. Metaphors are used to understand the unknown. This paper shows how we made a turn in student learning at the University of Almeria. Our hypothesis assumed that metaphors accelerate the acquisition of basic knowledge so that other skills built on that foundation are easily learned. With these goals in mind, we changed the way we teach by using metaphors and abstract concepts in a computer organisation course, a technical course in the first year of an information technology engineering degree. Cluster analysis of the data on collective student performance after this methodological change clearly identified two distinct groups. These two groups perfectly matched the before and after scenarios of the use of metaphors. The study was conducted during 11 academic years (2002/2003 to 2012/2013). The 475 observations made during this period illustrate the usefulness of this change in teaching and learning, shifting from a propositional teaching/learning model to a more dynamic model based on metaphors and abstractions. Data covering the whole period showed favourable evolution of student achievement and reduced failure rates, not only in this course, but also in many of the following more advanced courses.The paper is structured in five sections. The first gives an introduction, the second describes the methodology. The third section describes the sample and the study carried out. The fourth section presents the results and, finally, the fifth section discusses the main conclusions

    Genetic studies in sunflower broomrape

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    Much research has been conducted to identify sources of genetic resistance to sunflower broomrape (Orobanche cumana Wallr.) and to study their mode of inheritance. However, studies on the parasite have been scarce. This manuscript reviews three genetic studies in sunflower broomrape. First, the inheritance of the absence of pigmentation in a natural mutant of this species with yellow plant color phenotype was studied. In a first stage, lines from the unpigmented mutant and a normally pigmented population were developed by several generations of self-pollination. Plants of both lines were crossed and the F1, F2, and F3 generations were evaluated. The results indicated that plant pigmentation is controlled by a partially dominant allele at a single locus. Second, the unpigmented mutant was used to evaluate outcrossing potential of the species. Two experiments in which single unpigmented plants were surrounded by normally pigmented plants were conducted under pot and field conditions. The cross-fertilization rate was estimated as the percentage of F1 hybrids in the progenies of unpigmented plants, which averaged 21.5% in the pot and 28.8% in the field experiment. The results indicated that, under the conditions of this study, the species was not strictly self-pollinated. Finally, the inheritance of avirulence was studied in crosses of plants from lines of O. cumana races E and F, developed by several generations of self-pollination. The F1 and F3 generations were evaluated on the differential line P-1380 carrying the race-E resistance gene Or5. The results suggested that race E avirulence and race F virulence on P-1380 are allelic and controlled by a single locus, which confirmed the gene-for-gene theory for the O. cumana-sunflower interaction.The manuscript reviews research partially funded by Fundación Ramón Areces, Madrid. The contribution of Dr. Enrique Quesada Moraga, entomologist from the University of Córdoba, Spain, to taxonomic classification of pollinators is gratefully acknowledged. R. Pineda-Martos was the recipient of a PhD fellowship from the Spanish National Research Council (CSIC) (JAEPre_08_00370)Peer Reviewe

    VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory

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    VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages, 10 figures). Corresponding authors: A.Marinelli and D.Zaboro

    Efficacy and safety of preoperative preparation with Lugol''s iodine solution in euthyroid patients with Graves’ disease (LIGRADIS Trial): Study protocol for a multicenter randomized trial

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    Background: Currently, both the American Thyroid Association and the European Thyroid Association recommend preoperative preparation with Lugol''s Solution (LS) for patients undergoing thyroidectomy for Graves’ Disease (GD), but their recommendations are based on low-quality evidence. The LIGRADIS trial aims to provide evidence either to support or refute the systematic use of LS in euthyroid patients undergoing thyroidectomy for GD. Methods: A multicenter randomized controlled trial will be performed. Patients =18 years of age, diagnosed with GD, treated with antithyroid drugs, euthyroid and proposed for total thyroidectomy will be eligible for inclusion. Exclusion criteria will be prior thyroid or parathyroid surgery, hyperparathyroidism that requires associated parathyroidectomy, thyroid cancer that requires adding a lymph node dissection, iodine allergy, consumption of lithium or amiodarone, medically unfit patients (ASA-IV), breastfeeding women, preoperative vocal cord palsy and planned endoscopic, video-assisted or remote access surgery. Between January 2020 and January 2022, 270 patients will be randomized for either receiving or not preoperative preparation with LS. Researchers will be blinded to treatment assignment. The primary outcome will be the rate of postoperative complications: hypoparathyroidism, recurrent laryngeal nerve injury, hematoma, surgical site infection or death. Secondary outcomes will be intraoperative events (Thyroidectomy Difficulty Scale score, blood loss, recurrent laryngeal nerve neuromonitoring signal loss), operative time, postoperative length of stay, hospital readmissions, permanent complications and adverse events associated to LS. Conclusions: There is no conclusive evidence supporting the benefits of preoperative treatment with LS in this setting. This trial aims to provide new insights into future Clinical Practice Guidelines recommendations. Trial registration: ClinicalTrials.gov identifier: NCT03980132. © 202

    Effect of noise in CT image reconstruction using QR- Decomposition algorithm

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    [EN] The QR-Decomposition algorithm for CT 3D image reconstruction uses a linear system of equations to model the CT system response. Linear systems have a condition number that can be used to estimate the image noise. In this work the number of projections and the number of pixels in the detector have been studied to characterize the CT and the linear system of equations. The condition number of the system is estimated for the previous parameters used to generate the CT model with the aim of characterizing how these parameters affect the condition number and therefore bound the image noise level. It is shown that the condition number mainly depends on the size of pixels of the detector rather than the number of projections and this algorithm can be applied to low dose CT 3D image reconstruction without compromising image qualityThis work was supported by the Spanish Plan Nacional de Investigacion Científica, Desarrollo e Innovación Tecnológica (I+D+I) under Grant No. FIS2010-21216-CO2-01 and Valencian Local Government under Grants PROMETEOII/2013/010 and ISIC 2011/013Iborra, A.; Rodríguez-Álvarez, MJ.; Soriano, A.; Sánchez, F.; Bellido, P.; Conde, P.; Crespo, E.... (2013). Effect of noise in CT image reconstruction using QR- Decomposition algorithm. IEEE. 5-9. http://hdl.handle.net/10251/167122S5

    Dosimetric Calibration of Radiochromic Film For Laser-accelerated Proton Beams

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    [Otros] When an ultra-intense and ultra-short laser pulse interacts with solid matter a fraction of the laser pulse can be converted into kinetic energy of a beam of charged particles. Radiochromic film (RCF), widely used as radiation detector in the field of conventional radiotherapy, can be used as detector for laser-accelerated protons. If used in stack configuration it is a useful and versatile tool to obtain 2D spatial distribution and energetic information of proton beams. In order to obtain dosimetric information from RCF it must be properly calibrated. Irradiating film pieces under well known conditions allows us to establish a relation between the optical density (OD) of the radiochromic film, which is measured through a flat bed scanner operating in transmission mode, and the deposited energy in the active layer. A calibration curve over a large dynamic range (3 orders of magnitude) has been obtained for few MeV protons. Our calibration process has been performed at the Spanish National Accelerator Center at Sevilla. We have irradiated several areas of a single RCF with a constant 50 pA beam current and fixed 4 MeV energy from a 3 MV tandem accelerator. We have calculated the deposited energy in the films under the same conditions. We demonstrate that this technique can be used to measure the spectrum and total energy of a laser-accelerated mixed-energy proton beam. This detector has been calibrated for a near future application at the Center of Pulsed, Ultra-short, Ultra-intense Lasers (CLPU) at Salamanca (Spain). We present the calibration procedure and results, the design optimization, and a comparison with similar experiments.Project funded by the Spanish Ministry of Economy and Competitiveness and co-funded with FEDERs funds within the INNPACTO 2011 program. This work was supported by the Spanish Plan Nacional de Investigacion Cientifica, Desarrollo e InnovacionTecnologica (I+D+i) under Grant No. FIS2010-21216-CO2-01 and the Valencian Local Government under Grants PROMETEOII/2013/010 and ISIC 2011/013.Bellido, P.; Seimetz, M.; Soriano, A.; Huertas, C.; García Lopez, J.; Jimenez-Ramos, MC.; Fernandez, B.... (2013). Dosimetric Calibration of Radiochromic Film For Laser-accelerated Proton Beams. IEEE. 20-23. https://doi.org/10.1109/NSSMIC.2013.6829806S202
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