Test item taxonomy based of functional criteria

There are many taxonomies that try to classify and apply some consistency to the very many item types currently in existence. They all have various limitations, however, such as ambiguous classification criteria, little discrimination between format types, and referring almost exclusively to pen-and-paper or screen-based items. This paper aims to overcome these limitations by proposing a new item format taxonomy based on functional criteria. Current classifications are reviewed, the criteria they are based on are examined and their limitations are identified. The proposed alternative classification identifies four essential components of items according to function: the structure of the included content, the device used for transmission of the question to the examinee, the device for receiving the response, and the instructions to the examinee about how to understand and respond to the item. The combination of different facets of these four components allows any format of item to be classified, both existing formats and those that may appear in the future. In addition to systematically and coherently classifying items, this new taxonomy may also be of great utility in the construction and research of new items. The proposed model is illustrated by examples showing how specific items are classified, using a checklist as a guide.Ministerio de Economía y Competitividad de España PSI2014-56114-PMinisterio de Economía y Competitividad de España PSI2017-85724-

Manejo de herbicidas sintéticos y extractos vegetales para controlar malezas en cultivos básicos: maíz, frijol y sorgo.

La demanda en la producción y consumo de granos básicos como el maíz, fríjol y sorgo va en aumento, debido al requerimiento en la alimentación humana y animal. En México estos cultivos, sobretodo el maíz y frijol, se producen principalmente en agrosistemas de subsistencia, y la producción para cubrir la demanda es insuficiente, ya que existen diversos factores que afectan su rendimiento. Un factor que disminuye significativamente la producción en todos los cultivos es la presencia de malezas. El objetivo de esta investigación fue evaluar la actividad fitotóxica de los extractos de dos malezas consideradas alelopáticas (Parthenium hysterophorus y Ambrosia artemisiifolia), sobre tres especies cultivadas: maíz, frijol, sorgo y dos especies de maleza presentes en ellos, en comparación con la efectividad de dos herbicidas sintéticos. El propósito es contribuir al manejo integrado de malezas y la búsqueda de nuevos agentes que puedan funcionar como herbicidas biológicos.Esta investigación se realizó en dos etapas: Etapa 1: Se realizó la extracción de metabolitos secundarios de dos malezas invasoras P. hysterophorus L. (hierba del pájaro) y A. artemisiifolia L. (artemisa), utilizando dos métodos de extracción: extracción convencional sólido-líquido y extracción asistida por ultrasonido, empleando como solventes etanol al 70% y agua bidestilada. El método y solvente con mayor extracción de polifenoles totales en las dos especies vegetales fue; el método convencional sólido-líquido con solvente etanólico, que se aplicó en concentraciones de -1.5,- 3.5- y -6.5% en bioensayos de germinación y aspersión foliar en cinco especies vegetales; Zea mays L., Phaseolus vulgaris L., Sorghum bicolor L. Moench, Xanthium strumarium L. y Helianthus annuus L. Se presentó una inhibición total en los bioensayos de germinación de las cinco especies y una afectación del crecimiento en la maleza Helianthus annuus L. con la aplicación de extracto de A. artemisiifolia L, al 6.5% de concentración. Etapa 2, se realizó el establecimiento de experimentos de maíz, frijol y sorgo grano en campo, utilizando el diseño de bloques completos al azar con 6 tratamientos y 4 repeticiones; los tratamientos fueron: T1: Testigo T2: Control manual T3: Extracto de P, hysterophorus L T4: Extracto de A. artemisiifolia L. T5: Aplicación de 2-4D amina (maíz y sorgo) y Fomesafén (frijol) y T6: Dicamba (maíz y sorgo) y Basagran (frijol). Se identificaron las malezas presentes en cada unidad experimental. Las malezas con más frecuencia y dominancia en maíz y sorgo fueron I. trichocarpa y A. cristata., en frijol las malezas presentes fueron A. cristata y H. annuus. El control de malezas de hoja ancha después de 21 días fue del 95% con aplicación de herbicidas sintéticos. En los extractos naturales T3 y T4, se observaron quemaduras y marchitamiento durante los primeros siete días después de su aplicación, posteriormente la maleza emitió nuevos brotes y continúo creciendo. En el cultivo de maíz se observó una reducción en rendimiento de grano del 68%, y en fríjol el decremento en rendimiento de grano fue del 59% en los tratamientos con presencia de maleza durante todo el ciclo del cultivo comparado con el control manual T2. El cultivo del sorgo no presentó diferencia significativa en el rendimiento de forraje verde. ABSTRACT Production and consumption of basic grains as the corn, bean and sorghum is increasing, because of the requirement in the alimentation human and animal. These corps are produce in Mexico mainly with subsistence farming, the supply for consumption per capita it is insufficient; there are several factors that affect yield. A main factor of decreases production of crop is presence of weeds. The objective of this research was evaluated the phytotoxic activity of extracts from two weeds considered allelopathic (Parthenium hysterophorus and Ambrosia artemisiifolia) on three cultivated species: maize, beans and Sorghum and two species of weeds present in them, compared with the effectiveness of two synthetic herbicides. The purpose is contributed to the integrated management of weeds and the search for new agents that can function as biological herbicides. This research as perform in two stages. Stage 1: Extraction of secondary metabolites of two weeds invasive P, hysterophorus L. y A. artemisiifolia L. using two methods of extraction; by incubation in hybridization oven and ultrasound assisted extraction with ethanol and distilled water as solvents. The method and solvent with more extraction of total polyphenols in the two plants was: Method of incubation with ethanolic solvent; which was applied to concentrations 1.5, 3.5 and 6.5% in bioassays of germination and foliar aspersion in five plant species; Zea mays, Phaseolus vulgaris, Sorghum bicolor, Xanthium strumarium y Helianthus annuus. The results were total inhibition in bioassays of germination in the five-plant species, and affectation of weed growth H. annuus, with application of extract of A. artemisiifolia L., 6.5% concentration. Stage 2: I perform establishment of experiments in countryside of corn, bean and sorghum, using the experimental design randomized blocks, with 6 treatments and 4 repetitions; Weeds were identified, doing 4 samplings of 0.25 m² by experimental unit, they applied five methods of weed control where T1: uncontrolled, T2: manual control, T3: extract of P. hysterophorus L., T4: extract of A. artemisiifolia L. (6.5% of concentration) T5: 2-4D amina and Fluziafop-p-butil (5ml Lˉ¹) and T6: Dicamba and Bentazon (2.5 ml L ˉ¹). The weed with more frequency and dominance in crops corn and sorghum were I. trichocarpa y A. cristata. In bean the weeds present were A. cristata, and H. annuus. The control of weeds wide leaves after 21 days was 95% with application of synthetic herbicide. The natural extracts T3 and T4, were observed burns and withering in the leaf weed, seven days after of the application, later the weed issued new outbreaks and continued to grow. In corn crop was observed a reduction in grain yield 63% and in bean the decrement in grain yield was 54% in the treatments with presence of weeds throughout the crop cycle, compared to the T2. Crop sorghum was not significantly in forage green yield

Genealogical data of Boer and Nubian goats in Mexico

The pedigree file of the Boer and Nubian goat breeds in Mexico was constructed using the national database provided by the Asociación Mexicana de Criadores de Ganado Caprino de Registro. Field technicians routinely updated the goat national database by recording information from flocks participating in the performance-recording system. Information on animal identification number, parents, birth date, sex, breed, and farm of origin were used to undertake pedigree analyses using the ENDOG program (version 4.8). This paper presents a pedigree data file, tables and figures of characteristics of pedigree data, pedigree analyses, pedigree integrity, effective population size and genetic conservation index. The data can be used to estimate other population parameters, to monitor the genetic diversity of the Boer and Nubian goat breeds in Mexico, and also to design balanced breeding programs, maintaining genetic variation at reasonable levels and maximizing genetic progress in these populations.202

New guidelines for developing multiple-choice items

The rigorous construction of items constitutes a field of great current interest for psychometric researchers and practitioners. In previous studies we had reviewed and analyzed the existing guidelines for the construction of multiple-choice items. From this review emerged a new proposal for guidelines that is now, in the present work, subjected to empirical assessment. This assessment was carried out by users of the guidelines and by experts in item construction. The results endorse the proposal for the new guidelines presented, confirming the advantages in relation to their simplicity and efficiency, as well as permitting identification of the difficulties involved in drawing up and organizing some of the guidelines. Taking into account these results, we propose a new, refined set of guidelines that constitutes a useful, simple and structured instrument for the construction of multiple-choice items

Directrices para el desarrollo de ítems de elección múltiple basadas en validez

Background: Many different guidelines have been presented for the construction of multiple choice items. Those guidelines have been based on the observation of errors when constructing items but not on any clear scientifi c criterion. Our main objective was to draw up guidelines for the development of multiple choice items based on validity criteria. Method: We used the properties of adjustment, precision, and differentiation, applying them to three basic phases of instrument construction: the defi nition of the objective and its context; their expression in the instrument and item stem; and the elaboration of response options. Results: We have combined these properties and phases to give nine general guidelines with a fi rm theoretical footing. Conclusions: Finally, we have written a checklist with twentyfour points to check how far the measurement instruments comply with the proposed guidelines.Antecedentes: se han propuesto diferentes directrices para la construcción de ítems de elección múltiple, basadas sobre todo en la observación de errores al construir los ítems pero no en algún criterio científi co claro. El objetivo central del presente trabajo es generar directrices para el desarrollo de ítems de elección múltiple basadas en criterios de validez. Método: se utilizan las propiedades de ajuste, precisión y diferenciación, aplicándolas a tres etapas fundamentales del desarrollo de instrumentos de evaluación: defi nición del objetivo y su contexto, su implementación en el instrumento y enunciado de los ítems, y elaboración de las opciones de respuesta. Resultados: la combinación entre tales propiedades y etapas da lugar a nueve directrices generales que, además de quedar fundamentadas, permiten resolver cualquier duda que surja a quienes desarrollan ítems de elección múltiple. Conclusiones: para facilitar esa labor, las directrices son complementadas con una lista de veinticuatro cuestiones con la que comprobar el grado en que los instrumentos de medida cumplen las directrices propuestas

A report on the wildlife remains recovered in Cut E (1983-1985) of the Peña Negra (Crevillente, Alicante)

Se ofrece un análisis de los restos óseos recuperados en el yacimiento del Bronce Final de La Peña Negra (Crevillente, Alicante). El material estudiado consiste en una muestra preseleccionada por el excavador, lo que explica la ausencia de especímenes inidentificables, la anormal abundancia de huesos completos y la inexistencia de restos por debajo de una talla crítica. Ello obliga a ser cautos a la hora de valorar la fuente de subsistencia de estas gentes: bóvidos u ovinos. Las hipótesis formuladas en este trabajo deberán ser contrastadas con los resultados del análisis de la totalidad de la fauna del mismo nivel.The faunal analysis carried out on a previously selected sample from the assemblage recovered in Peña Negra (Late Bronze Age, Prov. Alicante) highlights all the weaknesses of a partial recovery of remains. Absence of unidentified specimens, abnormal abundance of complete bones and absence of bones below a critical size are evident in the sample studied. All of them force us to be suspicious as to the interpretation of the fauna which seems, nevertheless, dominated by domestic species, though, at the moment, (for the reasons given) we are unable to decide whether bovine or ovine husbandry was most important for the people at the site. The series of hypothesis which have been advanced in the present work will have to be substantiated through further research on the remaining fraction of this faunal assemblage. Rejection or adoption of these can only come through empirical testing with more reliable data than the ones presented here

Guidelines for the construction of multiple choice test items

Los ítems de elección múltiple son utilizados en numerosos contextos de evaluación psicológica y educativa. Con demasiada frecuencia las críticas que se hacen a este tipo de ítems tienen más que ver con su construcción defectuosa que con los inconvenientes del formato en sí mismo, que resulta objetivo, fácil y económico de corregir, y muy versátil, adaptándose a todo tipo de contextos y contenidos. El presente artículo destaca la necesidad de contar con un conjunto de directrices eficientes que guíen la construcción de dichos ítems, sustituyendo el modo intuitivo y poco sistemático seguido con frecuencia. Se revisan las directrices existentes y se identifican los diversos problemas que dificultan su aprovechamiento, tales como el elevado número de directrices propuestas, redundancias entre ellas y ciertas imprecisiones. A partir de esa revisión se seleccionan las directrices de contenido relevante y se reorganizan en un conjunto más parsimonioso y estructurado constituido por doce directrices básicas, acompañadas de ejemplos e ilustraciones. Se espera que esta propuesta resulte de utilidad como guía para los profesionales e investigadores que deseen construir ítems de elección múltiple o analizar los ya existentesMultiple choice test items are currently used in several areas of psychological and educational assessment. All too often, criticism made of these items concentrates more on their defective construction than the difficulties with the format itself; despite this, the format is objective, easily and cheaply corrected, and its versatility makes it adaptable to many contexts and contents. This paper highlights the need for a set of effective guidelines to assist in the construction of these items, thereby replacing the intuitive and unsystematic approach generally used. Existing guidelines are revised, as are several questions that stop them working properly, such as the excessive number of guidelines, overlapping between them and inaccuracies. Following this revision, the guidelines with important content are selected and reorganized in a more practical and structured set consisting of twelve basic guidelines, accompanied by examples and illustrations. It is hoped that this proposal will be useful as a guide for teachers or researchers who have to build multiple choice items, or analyze already existing ones

Time harmonic and static crack problems in 3-D transversely isotropic bodies

Boundary Elements XXVI, ISBN 1-85312-708-6Three dimensional crack problems in transversely isotropic solids under static and time harmonic dynamic loading conditions are studied in this paper using a mixed BE approach. Hypersingular and strongly singular kernels appearing in the formulation are regularized prior to any discretization. Two different crack geometries are studied. Stress Intensity Factors are computed from the crack opening displacements at quarter-point quadratic elements. The results obtained in this paper show a good agreement with other results. The number of elements required is rather small.Ministerio de Ciencia y Tecnología DPI2000-1217-C02-01Ministerio de Ciencia y Tecnología DPI2001-2377-C02-0

Estudio numérico de grietas en sólidos 3-D transversalmente isótropos

XVI Congreso Nacional de Ingeniería Mecánica, celebrado en León en 2004En este artículo se presentan resultados de problemas de Mecánica de la Fractura dinámica armónica en materiales transversalmente isótropos. Estos resultados han sido obtenidos mediante la aplicación de la formulación mixta del Método de los Elementos de Contorno desarrollada por los autores. Dicha formulación permite que tan solo sea necesario discretizar la superficie de la grieta y el contorno externo del problema. La formulación se valida mediante la comparación de algunos resultados con los obtenidos por otros autores. Posteriormente se resuelven otros problemas de gran interés pero más complicados para los que no existe solución previa conocida por los autoresResults for severa! problems of time harmonic Fracture Mechanics in transversely isotropic solids are presented in this paper. A Mixed Boundary Element Formulation developed by the authors has been used in order to obtain these results. Only the crack surface and the externa! boundary need to be discretized. Results obtained for sorne simple problems are compared with those obtained by other authors. Then, other interesting and more complex problems, for which no previous results are known by the authors, are solved.Ministerio de Ciencia y Tecnología DPI2000-12l 7-C02-0lMinisterio de Ciencia y Tecnología DPI2001-2377-C02-0