1,494 research outputs found

    La evaluación en la enseñanza de la Lengua.

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    El trabajo se inscribe en el discurso reformista de los noventa. Partiendo del marco conceptual de la Reforma, se hace un análisis crítico de la evaluación, en un sentido general y con derivaciones para el área de Lengua y Literatura. La tesis central que se defiende en el trabajo es que la evaluación es una actividad esencialmente ética y al mismo tiempo, actividad crítica de aprendizaje. En la media que el ejercicio de la evaluación esté orientada por el sentido de la justicia, la evaluación será formativa, idea que aquí se defiende como principal responsabilidad docente frente a otros objetivos y otras funciones menos explícitas en su declaración, pero que condicionan y anulan aquellos propósitos tan nobles y fundamentalmente educativos. El trabajo se desarrolla desde una perspectiva interdisciplinar y crítica. Didáctica, 10,189-213. Servicio de Publicaciones UCM. Madrid, 1998 190 Juan Manuel Álvarez Méndez PA L4BRAS-CLA VE: Reformo, evaluación, Lengua y Literatura, justicia, evaluación formativa, formación del profesor, evaluación como actividad crítica, interdisciplinariedad, curriculum, enseñanza, aprendizaje, didáctica, competencia comunicativa, curriculum oculto, educación lingúistica, aprendizaje funciona!, investigación cualitativa, positivismo, estructuralismo, entrevista, diálogo, participación, negociación, aprendizaje colaborativo

    Agronomic, economic and ecological aspects of the papaya (Carica papaya) production in Tabasco, Mexico

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    The cultivation of papaya is important in the tropic because it provides source of income to the farmer within a short time. Statistical data were obtained from farmers located in the Chontalpa, Rios and Centro-Sierra regions; the size of the survey was 67 farmers. The study shows the results of the farmers’ problem in a drastic reduction of their productivity because of the virosis and low prices in commercialization. The farmers were classified into three levels of technology, “low”, “middle” and “high”. The first one covers 88% of the farmers in seasonal conditions in contrast with the high technology that concentrates 4.5% in irrigation conditions. According to the technology used, the fertilizer shows more yields. Economically, the high technology had an internal tax return of 0.43 in comparison with the low technology of 0.25, which means that the investment is recovered with different yields. However, the use of high technology makes the system more competitive. Key words

    A new approach to categorize continuous variables in prediction models: Proposal and validation

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    When developing prediction models for application in clinical practice, health practitioners usually categorise clinical variables that are continuous in nature. Although categorisation is not regarded as advisable from a statistical point of view, due to loss of information and power, it is a common practice in medical research. Consequently, providing researchers with a useful and valid categorisation method could be a relevant issue when developing prediction models. Without recommending categorisation of continuous predictors, our aim is to propose a valid way to do it whenever it is considered necessary by clinical researchers. This paper focuses on categorising a continuous predictor within a logistic regression model, in such a way that the best discriminative ability is obtained in terms of the highest area under the receiver operating characteristic curve (AUC). The proposed methodology is validated when the optimal cut points' location is known in theory or in practice. In addition, the proposed method is applied to a real data set of patients with an exacerbation of chronic obstructive pulmonary disease, in the context of the IRYSS-COPD study where a clinical prediction rule for severe evolution was being developed. The clinical variable PCO2 was categorised in a univariable and a multivariable setting.MINECO: MTM2010-14913, MTM2011-28285-C02-01 and MTM2013-40941-P. Basque Government: IT620-13, 2012111008. University of the Basque Country UPV/EHU: GIU10/21, UFI11/52. Agrupamento IN-BIOMED from DXPCTSUG-FEDER unha maneira de facer Europa (2012/273). Red IRYSS (Investigación en Resultados y Servicios Sanitarios)- of the Instituto de Salud Carlos III: G03/22

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    Olean (1, 7-dioxaspiro[5.5]undecane): A novel intraspecific chemical cue in coraebus undatus (f.) (coleoptera: Buprestidae)

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    The main aim of this work was to identify semiochemicals from the jewel beetle Coraebus undatus (F.) (Coleoptera: Buprestidae) that may aid in the improvement of current monitoring tools. First, HS-SPME collections revealed that individually sampled adults (>7 days old) of both sexes release the spiroacetal 1, 7-dioxaspiro[5.5]undecane (olean). Electroantennographic recordings from both sexes exposed to increasing amounts of olean followed a dose-dependent pattern, with females being more responsive than males to the highest amount of the compound (100 µg). In double-choice assays, adults older than seven days were significantly attracted to olean, whereas this attraction was not detected in insects aged less than seven days. Indeed, a repellent effect was observed in young females. Subsequent field trials employing sticky purple prism traps revealed that there were no differences among the number of insects caught in control and olean-baited traps at two different release rates (0.75 and 3.75 mg/day). Interestingly, all the trapped specimens were determined as mated females, regardless of the presence of olean. Overall, these findings provide a basis for unraveling the chemical ecology of the species, although further research is still needed to determine the specific role of this compound within the chemical communication of the species. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

    Relativistic description of 3He(e,e'p)2H

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    The Relativistic Distorted-Wave Impulse Approximation is used to describe the 3^3He(e,epe,e^\prime p)2^2H process. We describe the 3^3He nucleus within the adiabatic hyperspherical expansion method with realistic nucleon-nucleon interactions. The overlap between the 3^3He and the deuteron wave functions can be accurately computed from a three-body calculation. The nucleons are described by solutions of the Dirac equation with scalar and vector (S-V) potentials. The wave function of the outgoing proton is obtained by solving the Dirac equation with a S-V optical potential fitted to elastic proton scattering data on the residual nucleus. Within this theoretical framework, we compute the cross section of the reaction and other observables like the transverse-longitudinal asymmetry, and compare them with the available experimental data measured at JLab.Comment: 4 pages, 3 figures. Proceedings of the 21st European Few Body Conference held in Salamanca (Spain) in August-September 201

    Northern Shrimp (Pandalus borealis, Krøyer) from EU-Spain Bottom Trawl Survey 2018 in NAFO Div. 3LNO

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    The Spanish Institute of Oceanography carried out in 2018 two bottom trawl surveys in the NAFO Regulatory Area in Division 3NO and 3L during the months of June and August respectively. The results on Northern shrimp (Pandalus borealis) are presented and compared with those from previous surveys from the same series. As recent years in 2018the shrimp catch (0.528 kg.) and estimated biomass (2.413 t.) in Divisions 3NO remain between the lowest of the series, confirming the decrease of shrimp importance from 2004. The Northern shrimp catches in 3L Division have declined from 2009, the shrimp catch (1352 kg.) and biomass estimated in 2018 (7807 t.) remain between the lowest values in the historical series

    PEF treatments of high specific energy permit the reduction of maceration time during vinification of Caladoc and Grenache grapes

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    Phenolic compounds extracted from the solid parts of the grapes during the maceration-fermentation stage define many of the sensory attributes of red wine such as color, bitterness or astringency. The effect of moderate a PEF treatment (M-PEF) (5 kV·cm-1, 8.8 kJ·kg-1) and an intense PEF treatment (I-PEF) (5 kV·cm-1, 52.9 kJ·kg-1) on the reduction of maceration time during vinification of Caladoc and Grenache grapes was investigated. In both grape varieties, M-PEF treatment combined with 4 days of maceration was the most effective treatment in achieving high anthocyanin content, color intensity and total phenol index at the end of fermentation. The I-PEF treatment promoted a rapid release of anthocyanins and phenolic compounds, along with a fast increment in the color intensity of the must after 24 h of maceration. Although the color intensity and anthocyanin content decreased significantly throughout fermentation when grape pomace was removed after 24 h, these parameters were similar, after 3 months of bottling, in the case of Caladoc and slightly lower in Grenache than the control wine, for which maceration was extended for 10 days. Therefore, results obtained in this investigation are the first to demonstrate the potential of I-PEF for the reduction of maceration time to 24 h in red winemaking

    Method for promoting in-situ hydrochar porosity in hydrothermal carbonization of almond shells with air activation

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    In this work, a new procedure for in situ hydrochar activation during hydrocarbonization of biomass (almond shell) is proposed. This approach suggests the addition of a controlled oxidizing gas stream (i.e. synthetic air) during the process for different periods of time, in order to promote the hydrochar porosity. Characterization of prepared materials revealed a noticeable development of porosity with apparent surfaces areas up to 320 m2/g. A highlighting variety of functional acid groups especially sensitive to air supply time was confirmed by surface chemistry analysis. Promising preliminary results show the effectiveness of this alternative approach synthesis strategy in converting a low value lignocellulosic biomass into porous materials with potential applications such as adsorption, electrical energy and gas storage or catalysis
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